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.github/workflows/build.yaml+26 Changelog.md+159 Doctest.hs−33 LICENSE+1−1 README.md+17 Setup.hs−6 cabal.project.haskell-nix+4 default.nix+7−5 docs/Makefile+19 docs/concepts/dbtype.rst+175 docs/concepts/expr.rst+74 docs/concepts/insert.rst+181 docs/concepts/queries.rst+274 docs/concepts/tables.rst+60 docs/conf.py+36 docs/cookbook.rst+169 docs/index.rst+53 docs/requirements.txt+4 docs/tutorial.rst+387 jobs.nix−5 nix/sources.json+36−36 nix/sources.nix+66−20 rel8.cabal+87−58 shell.nix+4−4 src/Rel8.hs+438−429 src/Rel8/Aggregate.hs+59−44 src/Rel8/Column.hs+31 src/Rel8/Column/ADT.hs+23 src/Rel8/Column/Either.hs+26 src/Rel8/Column/Lift.hs+23 src/Rel8/Column/List.hs+25 src/Rel8/Column/Maybe.hs+26 src/Rel8/Column/NonEmpty.hs+27 src/Rel8/Column/Null.hs+26 src/Rel8/Column/These.hs+29 src/Rel8/Expr.hs+65−24 src/Rel8/Expr.hs-boot+5−4 src/Rel8/Expr/Aggregate.hs+75−88 src/Rel8/Expr/Array.hs+19−14 src/Rel8/Expr/Bool.hs+8−42 src/Rel8/Expr/Default.hs+35 src/Rel8/Expr/Eq.hs+52−49 src/Rel8/Expr/Function.hs+8−38 src/Rel8/Expr/Null.hs+26−39 src/Rel8/Expr/Num.hs+71−41 src/Rel8/Expr/Opaleye.hs+29−15 src/Rel8/Expr/Ord.hs+64−57 src/Rel8/Expr/Order.hs+6 src/Rel8/Expr/Sequence.hs+22 src/Rel8/Expr/Serialize.hs+18−16 src/Rel8/Expr/Text.hs+66−11 src/Rel8/Expr/Time.hs+36−24 src/Rel8/Expr/Window.hs+121 src/Rel8/FCF.hs+26 src/Rel8/Generic/Construction.hs+352 src/Rel8/Generic/Construction/ADT.hs+478 src/Rel8/Generic/Construction/Record.hs+168 src/Rel8/Generic/Map.hs+49 src/Rel8/Generic/Record.hs+155 src/Rel8/Generic/Rel8able.hs+281 src/Rel8/Generic/Table.hs+103 src/Rel8/Generic/Table/ADT.hs+221 src/Rel8/Generic/Table/Record.hs+181 src/Rel8/Kind/Algebra.hs+38 src/Rel8/Kind/Context.hs+56 src/Rel8/Kind/Labels.hs−61 src/Rel8/Kind/Necessity.hs−38 src/Rel8/Opaque.hs−20 src/Rel8/Order.hs+7−1 src/Rel8/Query.hs+192−5 src/Rel8/Query.hs-boot+3−1 src/Rel8/Query/Aggregate.hs+37−3 src/Rel8/Query/Distinct.hs+12−9 src/Rel8/Query/Each.hs+7−4 src/Rel8/Query/Either.hs+35−30 src/Rel8/Query/Evaluate.hs+49 src/Rel8/Query/Exists.hs+22−13 src/Rel8/Query/Filter.hs+6 src/Rel8/Query/Indexed.hs+21 src/Rel8/Query/Limit.hs+4 src/Rel8/Query/List.hs+102−8 src/Rel8/Query/Maybe.hs+42−34 src/Rel8/Query/Null.hs+18−18 src/Rel8/Query/Opaleye.hs+41−5 src/Rel8/Query/Optimize.hs−200 src/Rel8/Query/Order.hs+1 src/Rel8/Query/Rebind.hs+27 src/Rel8/Query/SQL.hs+7−58 src/Rel8/Query/Set.hs+16−4 src/Rel8/Query/These.hs+63−54 src/Rel8/Query/Values.hs+5−2 src/Rel8/Query/Window.hs+26 src/Rel8/Schema/Column.hs−141 src/Rel8/Schema/Context.hs−144 src/Rel8/Schema/Context/Label.hs−67 src/Rel8/Schema/Context/Nullify.hs+110−131 src/Rel8/Schema/Context/Result.hs−198 src/Rel8/Schema/Field.hs+32−23 src/Rel8/Schema/Generic.hs−1021 src/Rel8/Schema/Generic/Test.hs−79 src/Rel8/Schema/HTable.hs+98−63 src/Rel8/Schema/HTable/Context.hs−26 src/Rel8/Schema/HTable/Either.hs+7−8 src/Rel8/Schema/HTable/Identity.hs+19−20 src/Rel8/Schema/HTable/Label.hs+33−94 src/Rel8/Schema/HTable/List.hs+2−2 src/Rel8/Schema/HTable/MapTable.hs+99 src/Rel8/Schema/HTable/Maybe.hs+6−7 src/Rel8/Schema/HTable/NonEmpty.hs+2−2 src/Rel8/Schema/HTable/Nullify.hs+68−97 src/Rel8/Schema/HTable/Pair.hs−20 src/Rel8/Schema/HTable/Product.hs+17 src/Rel8/Schema/HTable/Quartet.hs−29 src/Rel8/Schema/HTable/Quintet.hs−30 src/Rel8/Schema/HTable/These.hs+7−8 src/Rel8/Schema/HTable/Trio.hs−28 src/Rel8/Schema/HTable/Type.hs−56 src/Rel8/Schema/HTable/Vectorize.hs+72−143 src/Rel8/Schema/Kind.hs+24 src/Rel8/Schema/Name.hs+77 src/Rel8/Schema/Null.hs+110 src/Rel8/Schema/Nullability.hs−86 src/Rel8/Schema/Result.hs+54 src/Rel8/Schema/Spec.hs+18−55 src/Rel8/Schema/Spec/ConstrainContext.hs−23 src/Rel8/Schema/Spec/ConstrainDBType.hs−34 src/Rel8/Schema/Spec/ConstrainType.hs−31 src/Rel8/Schema/Structure.hs−53 src/Rel8/Schema/Table.hs+31 src/Rel8/Statement/Delete.hs+40−49 src/Rel8/Statement/Insert.hs+49−66 src/Rel8/Statement/OnConflict.hs+106 src/Rel8/Statement/Returning.hs+115−6 src/Rel8/Statement/SQL.hs+29 src/Rel8/Statement/Select.hs+122−36 src/Rel8/Statement/Set.hs+33 src/Rel8/Statement/Update.hs+44−61 src/Rel8/Statement/Using.hs+36 src/Rel8/Statement/View.hs+48−29 src/Rel8/Statement/Where.hs+31 src/Rel8/Table.hs+159−160 src/Rel8/Table/ADT.hs+173 src/Rel8/Table/Aggregate.hs+59−29 src/Rel8/Table/Alternative.hs+12−3 src/Rel8/Table/Bool.hs+21−8 src/Rel8/Table/Cols.hs+50 src/Rel8/Table/Either.hs+161−92 src/Rel8/Table/Eq.hs+71−35 src/Rel8/Table/HKD.hs+228 src/Rel8/Table/Insert.hs−39 src/Rel8/Table/Lifted.hs−62 src/Rel8/Table/List.hs+108−21 src/Rel8/Table/Maybe.hs+149−83 src/Rel8/Table/Name.hs+37−13 src/Rel8/Table/NonEmpty.hs+111−19 src/Rel8/Table/Null.hs+147 src/Rel8/Table/Nullify.hs+211 src/Rel8/Table/Opaleye.hs+97−76 src/Rel8/Table/Ord.hs+83−49 src/Rel8/Table/Order.hs+20−20 src/Rel8/Table/Projection.hs+73 src/Rel8/Table/Recontextualize.hs−162 src/Rel8/Table/Rel8able.hs+92 src/Rel8/Table/Serialize.hs+72−374 src/Rel8/Table/These.hs+234−110 src/Rel8/Table/Transpose.hs+46 src/Rel8/Table/Undefined.hs+7−7 src/Rel8/Table/Window.hs+43 src/Rel8/Tabulate.hs+549−141 src/Rel8/Type.hs+53−57 src/Rel8/Type/Array.hs+56−36 src/Rel8/Type/Array1D.hs−135 src/Rel8/Type/Composite.hs+135 src/Rel8/Type/Enum.hs+139 src/Rel8/Type/Eq.hs+8−39 src/Rel8/Type/Information.hs+11−34 src/Rel8/Type/JSONBEncoded.hs+5−2 src/Rel8/Type/JSONEncoded.hs+4−13 src/Rel8/Type/Monoid.hs+10−10 src/Rel8/Type/Num.hs+20−2 src/Rel8/Type/Ord.hs+18−19 src/Rel8/Type/ReadShow.hs+14−14 src/Rel8/Type/Semigroup.hs+13−13 src/Rel8/Type/String.hs+5 src/Rel8/Type/Sum.hs+7−3 src/Rel8/Type/Tag.hs+14−1 src/Rel8/Window.hs+97 tests/Main.hs+340−237 tests/Rel8/Generic/Rel8able/Test.hs+188
.github/workflows/build.yamlnew file+26
@@ -0,0 +1,26 @@
1+name: Build
2+on: [push, pull_request, release]
3+jobs:
4+ build:
5+ runs-on: ubuntu-latest
6+ steps:
7+ - uses: actions/checkout@v2.3.4
8+ with:
9+ persist-credentials: false
10+ submodules: true
11+
12+ - uses: cachix/install-nix-action@v14.1
13+ with:
14+ nix_path: nixpkgs=channel:nixos-unstable
15+ extra_nix_config: |
16+ trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ=
17+ substituters = https://cache.nixos.org/ https://cache.iog.io
18+
19+ - uses: cachix/cachix-action@v10
20+ with:
21+ name: rel8
22+ authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
23+
24+ - run: nix-build -A hsPkgs.rel8.components.library
25+ - run: nix-build -A hsPkgs.rel8.checks.tests
26+ - run: nix-build shell.nix
Changelog.mdnew file+159
@@ -0,0 +1,159 @@
1+# 1.4.0.0 (2002-08-17)
2+
3+## Breaking changes
4+
5+* The behavior of `greatest`/`least` has been corrected, and was previously flipped. ([#183](https://github.com/circuithub/rel8/pull/183))
6+
7+## New features
8+
9+* `NullTable`/`HNull` have been added. This is an alternative to `MaybeTable` that doesn't use a tag columns. It's less flexible (no `Functor` or `Applicative` instance) and is meaningless when used with a table that has no non-nullable columns (so nesting `NullTable` is redundant). But in situations where the underlying `Table` does have non-nullable columns, it can losslessly converted to and from `MaybeTable`. It is useful for embedding into a base table when you don't want to store the extra tag column in your schema. ([#173](https://github.com/circuithub/rel8/pull/173))
10+* Add `fromMaybeTable`. ([#179](https://github.com/circuithub/rel8/pull/179))
11+* Add `alignMaybeTable`. ([#196](https://github.com/circuithub/rel8/pull/196))
12+
13+## Improvements
14+
15+* Optimize implementation of `AltTable` for `Tabulation` ([#178](https://github.com/circuithub/rel8/pull/178))
16+
17+## Other
18+
19+* Documentation improvements for `HADT`. ([#177](https://github.com/circuithub/rel8/pull/177))
20+* Document example usage of `groupBy`. ([#184](https://github.com/circuithub/rel8/pull/184))
21+* Build with and require Opaleye >= 0.9.3.3. ([#190](https://github.com/circuithub/rel8/pull/190))
22+* Build with `hasql` 1.6. ([#195](https://github.com/circuithub/rel8/pull/195))
23+
24+# 1.3.1.0 (2022-01-20)
25+
26+## Other
27+
28+* Rel8 now requires Opaleye >= 0.9.1. ([#165](https://github.com/circuithub/rel8/pull/165))
29+
30+# 1.3.0.0 (2022-01-31)
31+
32+## Breaking changes
33+
34+* `div` and `mod` have been changed to match Haskell semantics. If you need the PostgreSQL `div()` and `mod()` functions, use `quot` and `rem`. While this is not an API change, we feel this is a breaking change in semantics and have bumped the major version number. ([#155](https://github.com/circuithub/rel8/pull/155))
35+
36+## New features
37+
38+* `divMod` and `quotRem` functions have been added, matching Haskell's `Prelude` functions. ([#155](https://github.com/circuithub/rel8/pull/155))
39+* `avg` and `mode` aggregation functions to find the mean value of an expression, or the most common row in a query, respectively. ([#152](https://github.com/circuithub/rel8/pull/152))
40+* The full `EqTable` and `OrdTable` classes have been exported, allowing for instances to be manually created. ([#157](https://github.com/circuithub/rel8/pull/157))
41+* Added `like` and `ilike` (for the `LIKE` and `ILIKE` operators). ([#146](https://github.com/circuithub/rel8/pull/146))
42+
43+## Other
44+
45+* Rel8 now requires Opaleye 0.9. ([#158](https://github.com/circuithub/rel8/pull/158))
46+* Rel8's test suite supports Hedgehog 1.1. ([#160](https://github.com/circuithub/rel8/pull/160))
47+* The documentation for binary operations has been corrected. ([#162](https://github.com/circuithub/rel8/pull/162))
48+
49+# 1.2.2.0 (2021-11-21)
50+
51+## Other
52+
53+* Support GHC 9.2 ([#145](https://github.com/circuithub/rel8/pull/145))
54+* Correct the documentation for `except` ([#147](https://github.com/circuithub/rel8/pull/147))
55+* Support `hasql` 1.5 ([#149](https://github.com/circuithub/rel8/pull/149))
56+
57+# 1.2.1.0 (2021-11-21)
58+
59+## New features
60+
61+* `castTable` has been added, which casts all columns selected from in `Query` according to the types of columns. This can occasionally be useful when using `many`/`some` on older PostgreSQL versions. ([#137](https://github.com/circuithub/rel8/pull/137))
62+
63+* Added `<:`, `<=:`, `>:`, `>=:`, `greatest` and `least`, which sort all columns in a table lexicographically. These operators are like the `<.` operators which operate on `Expr`s, but the `<:` operate on entire tables. ([#139](https://github.com/circuithub/rel8/pull/139))
64+
65+## Other
66+
67+* Support opaleye-0.8 ([#142](https://github.com/circuithub/rel8/pull/142))
68+
69+# 1.2.0.0 (2021-10-22)
70+
71+## New features
72+
73+* New `$*` and `$+` operators for projecting out of `ListTable` and `NonEmptyTable` respectively (analogous to the existing `$?` for `MaybeTable`). ([#125](https://github.com/circuithub/rel8/pull/125))
74+
75+## Bug fixes
76+
77+* Fix `UPSERT` support (and add tests), which was broken due to a typo inside Rel8 that made it impossible to construct `Projection`s which are needed by `UPSERT`. ([#134](https://github.com/circuithub/rel8/pull/134))
78+
79+* Remove `DBMin` and `DBMax` instances for `Bool`, which are invalid as far as Postgres is concerned. `and` and `or` can be used to achieve the same thing. ([#126](https://github.com/circuithub/rel8/pull/126))
80+
81+* Fix `aggregateMaybeTable`, `aggregateEitherTable` and `aggregateTheseTable`, which generated invalid SQL previously. ([#127](https://github.com/circuithub/rel8/pull/127))
82+
83+## Breaking changes
84+
85+* `rebind` now takes an additional argument for the "name" of the binding. ([#128](https://github.com/circuithub/rel8/pull/128))
86+
87+# 1.1.0.0 (2021-07-16)
88+
89+## New features
90+
91+* You can derive `Rel8able` for "vanilla" higher-kinded data types - data types that don't use the `Column` type family. For example, the following is now possible:
92+
93+ ```haskell
94+ data MyTable f = MyTable
95+ { myTableX :: f Int32
96+ , myTableY :: f Text
97+ } deriving (Generic, Rel8able)
98+ ```
99+
100+* The `Projectable` and `Biprojectable` type classes have been introduced. These classes model a type of functors and bifunctors (respectively) on tables, where the mapping function is only able to rearrange columns. For example, the following is now possible:
101+
102+ ```haskell
103+ x <- project myTableX <$> many ...
104+ ```
105+
106+* `Insert`'s `onConflict` field now has a new option - `DoUpdate`. This maps to PostgreSQL's `ON CONFLICT DO UPDATE` syntax, which provides upsert support. ([#85](https://github.com/circuithub/rel8/pull/85))
107+
108+* `Insert`, `Update` and `Delete` has all been expanded to work with `Query`s. In particular:
109+
110+ * `Delete` now supports a `USING` sub-query
111+ * `Update` now supports a `FROM` sub-query
112+ * `Insert` can delete the result of any arbitrary `Query` (providing the types match)
113+
114+* The new `Rel8.Tabulate` module has been added, which gives a `Map`-esque interface to writing and composing queries. ([#70](https://github.com/circuithub/rel8/pull/70))
115+
116+* The new `indexed` `Query -> Query` function was added. This function augments each row in a query with it's 0-based index. ([#117](https://github.com/circuithub/rel8/pull/117))
117+
118+## Breaking changes
119+
120+* `Insert`, `Delete` and `Update` have all changed. In particular, for `Insert` users should now replace `rows = xs` with `rows = values xs`. ([#85](https://github.com/circuithub/rel8/pull/85))
121+
122+* Rename `whereExists` and `whereNotExists` to `present` and `absent` respectively. ([#57](https://github.com/circuithub/rel8/pull/57))
123+
124+* Simplify `evaluate` to run directly inside the `Query` monad, rendering the `Evaluate` monad unnecessary. ([#56](https://github.com/circuithub/rel8/pull/56))
125+
126+* The `Labelable` type class has been removed as it's no longer necessary. This class was mostly internal, though was visible in some public API functions. ([#76](https://github.com/circuithub/rel8/pull/76))
127+
128+* `EitherTable`, `ListTable`, `MaybeTable`, `NonEmptyTable` and `TheseTable` now all have an extra parameter which tracks the context of the table. If you manually specified any types before, you need to provide this parameter - usually `Expr` will be the correct choice. ([#101](https://github.com/circuithub/rel8/pull/101))
129+
130+* We've done a lot of work to simplify the internals of Rel8, but some of these are breaking changes. However, most of these API changes shouldn't affect users as they are mostly types used in type inference, or affect classes where users don't need to define their own instances.
131+
132+ * The kind of a `Rel8able` is now `(Type -> Type) -> Type`. Previously it was `(X -> Type) -> Type`.
133+ * `Table` has a new associated type - `FromExprs`. This was previously an open type family.
134+ * `Table` has a new associated type - `Transpose` - and `Recontextualise` has been renamed to `Transposes`. This `Transposes` class now operates in terms of `Transpose`.
135+
136+* `select`, `insert`, `update` and `delete` now produce Hasql `Statement`s, rather than actually running the statement as IO. This allows Rel8 to be used with transaction/connection-managing monads like [`hasql-transaction`](https://hackage.haskell.org/package/hasql-transaction). ([#94](https://github.com/circuithub/rel8/pull/94))
137+
138+## Bug fixes
139+
140+* Fixes a bug where cartesian products of queries using `catListTable`, `catNonEmptyTable`, `catList` and `catNonEmpty` would incorrectly be zipped instead. ([#61](https://github.com/circuithub/rel8/pull/61))
141+
142+* Require Opaleye 0.7.3.0. This version has better support for lateral queries, which can improve query plans, especially in `optional`/`LEFT JOIN` ([#72](https://github.com/circuithub/rel8/pull/72))
143+
144+* Rel8 now compiles with GHC 9. ([#97](https://github.com/circuithub/rel8/pull/97))
145+
146+## Other changes
147+
148+* `exists` is now implemented in terms of the SQL `EXISTS` keyword. ([#69](https://github.com/circuithub/rel8/pull/69))
149+
150+* `alignBy` no longer requires `Table`s. ([#67](https://github.com/circuithub/rel8/pull/67))
151+
152+
153+# 1.0.0.1 (2021-06-21)
154+
155+This release contains various fixes for documentation.
156+
157+# 1.0.0.0 (2021-06-18)
158+
159+* Initial release.
Doctest.hsdeleted−33
@@ -1,33 +0,0 @@
1−{-# language BlockArguments #-}
2−{-# language OverloadedStrings #-}
3−
4−module Main where
5−
6−import Build_doctests ( flags, pkgs, module_sources )
7−import Control.Exception ( bracket, throwIO )
8−import Data.ByteString.Char8 ( unpack )
9−import Data.Foldable ( traverse_ )
10−import Database.PostgreSQL.Simple ( connectPostgreSQL, close, execute_ )
11−import Database.Postgres.Temp ( toConnectionString, with, withConfig, verboseConfig )
12−import System.Environment ( setEnv )
13−import System.Environment.Compat ( unsetEnv )
14−import Test.DocTest ( doctest )
15−
16−main :: IO ()
17−main = do
18− unsetEnv "GHC_ENVIRONMENT" -- see 'Notes'; you may not need this
19− either throwIO return =<< with \db -> do
20− setEnv "TEST_DATABASE_URL" (unpack (toConnectionString db))
21− bracket (connectPostgreSQL (toConnectionString db)) close \conn -> do
22− execute_ conn "create table author ( author_id serial primary key, name text not null, url text )"
23− execute_ conn "create table project ( author_id int not null references author (author_id), name text not null )"
24−
25− execute_ conn "insert into author ( name, url ) values ( 'Ollie', 'https://ocharles.org.uk' )"
26− execute_ conn "insert into author ( name, url ) values ( 'Bryan O''Sullivan', null )"
27− execute_ conn "insert into project ( author_id, name ) values ( 1, 'rel8' )"
28− execute_ conn "insert into project ( author_id, name ) values ( 2, 'aeson' )"
29−
30− doctest args
31−
32− where
33− args = flags ++ pkgs ++ module_sources
LICENSE+1−1
@@ -1,4 +1,4 @@
1−Copyright 2020 Oliver Charles
1+Copyright 2021 Oliver Charles
22
33All rights reserved.
44
README.mdnew file+17
@@ -0,0 +1,17 @@
1+# Welcome!
2+
3+Welcome to Rel8! Rel8 is a Haskell library for interacting with PostgreSQL databases, built on top of the fantastic Opaleye library.
4+
5+The main objectives of Rel8 are:
6+
7+* *Conciseness*: Users using Rel8 should not need to write boiler-plate code. By using expressive types, we can provide sufficient information for the compiler to infer code whenever possible.
8+
9+* *Inferrable*: Despite using a lot of type level magic, Rel8 aims to have excellent and predictable type inference.
10+
11+* *Familiar*: writing Rel8 queries should feel like normal Haskell programming.
12+
13+Rel8 was presented at ZuriHac 2021. If you want to have a brief overview of what Rel8 is, and a tour of the API - check out the video below:
14+
15+[![Rel8 presentation at ZuriHac 2021](https://img.youtube.com/vi/3uwrtjxiq6E/hqdefault.jpg)](http://www.youtube.com/watch?v=3uwrtjxiq6E)
16+
17+For more details, check out the [official documentation](https://rel8.readthedocs.io/en/latest/).
Setup.hsdeleted−6
@@ -1,6 +0,0 @@
1−module Main where
2−
3−import Distribution.Extra.Doctest (defaultMainWithDoctests)
4−
5−main :: IO ()
6−main = defaultMainWithDoctests "doctests"
cabal.project.haskell-nixnew file+4
@@ -0,0 +1,4 @@
1+-- Haskell.nix overrides. We don't put these in cabal.project, because Cabal
2+-- will interpret them as local packages, and try to build them when we cabal
3+-- build. The only reason we have to specify these is for Haskell.nix to know to
4+-- override these packages by fetching them rather than using Hackage.
default.nix+7−5
@@ -1,24 +1,26 @@
1−let
1+let
22 haskellNix = import (import ./nix/sources.nix)."haskell.nix" {};
33
4− nixpkgsSrc = haskellNix.sources.nixpkgs-2009;
4+ nixpkgsSrc = haskellNix.sources.nixpkgs-unstable;
55
66 nixpkgsArgs = haskellNix.nixpkgsArgs;
77
8− compiler-nix-name = "ghc8103";
8+ compiler-nix-name = "ghc924";
99
1010 pkgs = import nixpkgsSrc nixpkgsArgs;
1111
12−in
12+in
1313pkgs.haskell-nix.project {
1414 inherit compiler-nix-name;
1515
16+ cabalProjectLocal = builtins.readFile ./cabal.project.haskell-nix;
17+
1618 src = pkgs.haskell-nix.haskellLib.cleanGit {
1719 name = "rel8";
1820 src = ./.;
1921 };
2022
21− modules = [
23+ modules = [
2224 { packages.rel8 = {
2325 preCheck = ''
2426 export PATH="${pkgs.postgresql}/bin:${"$PATH"}"
docs/Makefilenew file+19
@@ -0,0 +1,19 @@
1+# Minimal makefile for Sphinx documentation
2+#
3+
4+# You can set these variables from the command line.
5+SPHINXOPTS =
6+SPHINXBUILD = sphinx-build
7+SOURCEDIR = .
8+BUILDDIR = _build
9+
10+# Put it first so that "make" without argument is like "make help".
11+help:
12+ @$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
13+
14+.PHONY: help Makefile
15+
16+# Catch-all target: route all unknown targets to Sphinx using the new
17+# "make mode" option. $(O) is meant as a shortcut for $(SPHINXOPTS).
18+%: Makefile
19+ @$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
docs/concepts/dbtype.rstnew file+175
@@ -0,0 +1,175 @@
1+``DBType``
2+==========
3+
4+The ``DBType`` type class provides a bridge between database expression values
5+and Haskell values. Rel8 comes with stock instances for most types that come
6+predefined with PostgreSQL, such as `int4` (which is represented as by
7+``Data.Int.Int32``) and timestamptz (which is ``UTCTime`` from ``Data.Time``).
8+This means that you need at least one ``DBType`` instance per database type,
9+though most of these primitive ``DBType``\s should already be available.
10+
11+Combining ``newtype`` and ``DBType``
12+------------------------------------
13+
14+You can define new instances of ``DBType`` by using Haskell "generalized
15+newtype deriving" strategy. This is useful when you have a common database
16+type, but need to interpret this type differently in different contexts. A very
17+common example here is with auto-incrementing ``id`` counters. In PostgreSQL,
18+it's common for a table to have a primary key that uses the ``serial`` type,
19+which means the key is an ``int8`` with a default value for ``INSERT``. In
20+Rel8, we could use ``Int64`` (as ``Int64`` is the ``DBType`` instance for
21+``int8``), but we can be even clearer if we make a ``newtype`` for each *type*
22+of id.
23+
24+If our database has users and orders, these tables might both have ids, but
25+they are clearly not meant to be treated as a common type. Instead, we can make
26+these types clearly different by writing::
27+
28+ newtype UserId = UserId { getUserId :: Int64 }
29+ deriving newtype DBType
30+
31+ newtype OrderId = OrderId { getOrderId :: Int64 }
32+ deriving newtype DBType
33+
34+Now we can use ``UserId`` and ``OrderId`` in our Rel8 queries and definitions,
35+and Haskell will make sure we don't accidentally use an ``OrderId`` when we're
36+looking up a user.
37+
38+If you would like to use this approach but can't use generalized newtype
39+deriving, the same can be achived by using ``mapTypeInformation``::
40+
41+ instance DBType UserId where
42+ typeInformation = mapTypeInformation UserId getUserId typeInformation
43+
44+Parsing with ``DBType``
45+-----------------------
46+
47+``DBType``\s can also *refine* database types with parsing, which allows you to
48+map more structured Haskell types to a PostgreSQL database. This allows you to
49+use the capabalities of Haskell's rich type system to make it harder to write
50+incorrect queries. For example, we might have a database where we need to store
51+the status of an order. In Haskell, we might write:
52+
53+.. code-block:: haskell
54+
55+ data OrderStatus = PaymentPending | Paid | Packed | Shipped
56+
57+In our PostgreSQL we have a few choices, but for now we'll assume that they are
58+stored as ``text`` values.
59+
60+In order to use this type in Rel8 queries, we need to write an instance of
61+``DBType`` for ``OrderStatus``. One approach is to use
62+``parseTypeInformation``, which allows you to refine an existing ``DBType``::
63+
64+ instance DBType OrderStatus where
65+ typeInformation = parseTypeInformation parser printer typeInformation
66+ where
67+ parser :: Text -> Either String OrderStatus
68+ parser "PaymentPending" = Right PaymentPending
69+ parser "Paid" = Right Paid
70+ parser "Packed" = Right Packed
71+ parser "Shipped" = Right Shipped
72+ parser other = Left $ "Unknown OrderStatus: " <> unpack other
73+
74+ printer :: OrderStatus -> Text
75+ printer PaymentPending = "PaymentPending"
76+ printer Paid = "Paid"
77+ printer Packed = "Packed"
78+ printer Shipped = "Shipped"
79+
80+Deriving ``DBType`` via ``ReadShow``
81+------------------------------------
82+
83+The ``DBType`` definition for ``OrderStatus`` above is a perfectly reasonable
84+definition, though it is quite verbose and tedious. Rel8 makes it easy to map
85+Haskell types that are encoded using ``Read``/``Show`` via the ``ReadShow``
86+wrapper. An equivalent ``DBType`` definition using ``ReadShow`` is::
87+
88+ data OrderStatus = PaymentPending | Paid | Packed | Shipped
89+ deriving stock (Read, Show)
90+ deriving DBType via ReadShow OrderStatus
91+
92+Storing structured data with ``JSONEncoded``
93+--------------------------------------------
94+
95+It can occasionally be useful to treat PostgreSQL more like a document store,
96+storing structured documents as JSON objects. Rel8 comes with support for
97+serializing values into structured representations through the ``JSONEncoded``
98+and ``JSONBEncoded`` deriving-via helpers.
99+
100+There usage is very similar to ``ReadShow`` - simply derive ``DBType via
101+JSONEncoded``, and Rel8 will use ``ToJSON`` and ``FromJSON`` instances (from
102+``aeson``) to serialize the given type.
103+
104+For example, a project might use event sourcing with a table of events. Each
105+row in this table is an event, but this event is stored as a JSON object. We
106+can use this type with Rel8 by writing::
107+
108+ data Event = UserCreated UserCreatedData | OrderCreated OrderCreatedData
109+ deriving stock Generic
110+ deriving anyclass (ToJSON, FromJSON)
111+ deriving DBType via JSONBEncoded Event
112+
113+Here we used ``JSONBEncoded``, which will serialize to PostgreSQL ``jsonb``
114+(binary JSON) type, which is generally the best choice.
115+
116+The ``DBType`` subtypes
117+-----------------------
118+
119+``DBEq``
120+^^^^^^^^
121+
122+The ``DBEq`` type class represents the subclass of database types that support
123+equality. By supporting equality, we mean that a type supports the ``=``
124+operator, and also has a suitable notion of equality for operations like
125+``GROUP BY`` and ``DISTINCT``. On the one hand, this class is like Haskell's
126+``Eq`` type class. The main difference is that this class has no methods.
127+
128+``DBOrd``
129+^^^^^^^^^
130+
131+The ``DBOrd`` type class represents the subclass of database types that support
132+the normal comparison operators - ``<``, ``<=``, ``>=`` and ``>``.
133+
134+``DBMax`` and ``DBMin``
135+^^^^^^^^^^^^^^^^^^^^^^^
136+
137+The type classes indicate that a database type supports the ``min()`` and
138+``max()`` aggregation functions.
139+
140+``DBSemigroup`` and ``DBMonoid``
141+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
142+
143+These type classes exist to give Rel8's API a similar feel to Haskell
144+programming. Many database types have a sensible monoid structure, with the
145+presence of a ``mempty``-like expression, and an associative operation to
146+combine ``Expr``\s.
147+
148+``DBNum``, ``DBIntegral`` and ``DBFractional``
149+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
150+
151+These type classes are used to present a familiar numeric type hierarchy for
152+Haskell programmers.
153+
154+``DBNum``
155+ This class indicates that a type supports the ``+``, ``-``, and ``*``
156+ operators, along with the ``abs()``, ``negate()`` and ``sign()`` functions.
157+ Database types that are instances of ``DBNum`` allow ``Num (Expr a)`` to be
158+ used (allowing you to combine expressions with Haskell's normal ``+``
159+ function).
160+
161+``DBIntegral``
162+ If a type is an instance of ``DBIntegral``, it means that the type stores
163+ integral (whole) numbers. The ``Rel8.Expr.Num`` module provides familiar
164+ ``Expr`` functions like ``fromIntegral`` to convert between types.
165+
166+``DBFractional``
167+ If a type is an instance of ``DBFraction``, it means that the type supports
168+ the ``/`` operator, and literals can be created via Haskell's ``Rational``
169+ type class. This type class provides the ``Fracitonal (Expr a)`` instance.
170+
171+``DBString``
172+^^^^^^^^^^^^
173+
174+This type class indicates that a database type supports the ``string_agg()``
175+aggregation function.
docs/concepts/expr.rstnew file+74
@@ -0,0 +1,74 @@
1+``Expr`` and ``Sql``
2+====================
3+
4+``Expr``
5+--------
6+
7+Now that we've seen how types are bridged between a database and Haskell via
8+``DBType``, we can start looking at how expressions are modelled. In Rel8, any
9+expression will be a value of the form ``Expr a``, where ``a`` is the type of
10+the expression. For example, the SQL expression ``user.id = 42`` is an ``Expr
11+Bool``, and the subexpressions ``user.id`` and ``42`` might be ``Expr
12+UserId``\s.
13+
14+``Expr``\s are usually created by combining other ``Expr``\s together, like
15+using numeric operations like `+` and `*`, or by quoting Haskell values into
16+queries with ``lit``. Continuing with the example of ``user.id = 42``, we can
17+write this in Rel8 as::
18+
19+ userId ==. lit (UserId 42)
20+
21+Here it's assumed that a ``userId :: Expr UserId`` expression is already in
22+scope, and we can compare that against another ``Expr UserId`` using the ``==.``
23+operator (which is like Haskell's normal ``==`` operator, but lifted to work on
24+``Expr``). The expression ``lit (UserId 42)`` quotes the Haskell term ``UserId
25+42`` literally as the SQL expression ``42``. This particular encoding is chosen
26+because ``UserId`` is simply a ``newtype`` around ``Int64``.
27+
28+``null``
29+--------
30+
31+So far we've only talked about ``DBType``, which represents database types
32+*excluding* ``null``. Rel8 chooses this encoding because ``null`` is rather
33+special in SQL, and doesn't really constitute a distinct type. For example,
34+there is no SQL notion of "stacking" nulls - which is to say a type like ``Maybe
35+(Maybe UserId))`` has no real analogous type in SQL.
36+
37+Of course, as ``null`` is pervasive in SQL queries, Rel8 does support ``null`` -
38+simply wrap up your type in ``Maybe``. ``Nothing`` will be translated as
39+``null``, and ``Just`` is used to represent non-null values.
40+
41+Rel8 comes with a set of functions to work with ``null`` values thash should
42+feel familiar to Haskell programmers:
43+
44+* ``null`` creates null values (you can also use ``lit Nothing``).
45+* ``nullify`` turns an ``Expr a`` into a ``Expr (Maybe a)`` (like ``Just``).
46+* ``nullable`` allows you to eliminate null values, like the ``maybe`` function.
47+* ``isNull`` and ``isNonNull`` work like ``isNothing`` and ``isJust``,
48+ respectively.
49+* ``mapNullable`` is like ``fmap`` for ``Maybe``, and allows you to map over
50+ non-null values.
51+* ``liftOpNullable`` is like ``liftA2`` for ``Maybe``, and allows you to combine
52+ expressions together, given a way to combine non-null expressions.
53+
54+``SQL`` and null-polymorphic expressions
55+----------------------------------------
56+
57+Through the API reference documentation for Rel8, you might encounter the
58+``Sql`` type class. For example, if we look at the type of ``litExpr``, we
59+have::
60+
61+ litExpr :: Sql DBType a => a -> Expr a
62+
63+Here ``Sql DBType a`` means that ``a`` can either be literally a type that has
64+an instance of ``DBType`` (like ``UserId`` or ``Bool``), *or* that same type
65+wrapped in ``Maybe`` (so ``Maybe UserId`` or ``Maybe Bool``). ``Maybe`` here
66+encodes the SQL concept of ``null``.
67+
68+Some functions work regardless of whether or not a value is null, and in these
69+cases you'll see ``Sql DBType a``. ``Sql`` can be used with any ``DBType``
70+subtype. For example, the type of ``div`` is::
71+
72+ div :: Sql DBIntegral a => Expr a -> Expr a -> Expr a
73+
74+Which means ``div`` works on any ``DBIntegral a``, including ``Maybe a``.
docs/concepts/insert.rstnew file+181
@@ -0,0 +1,181 @@
1+``INSERT``, ``UPDATE`` and ``DELETE``
2+=====================================
3+
4+While the majority of Rel8 is about building and executing ``SELECT``
5+statement, Rel8 also has support for ``INSERT``, ``UPDATE`` and ``DELETE``.
6+These statements are all executed using the ``insert``, ``update`` and
7+``delete`` functions, all of which take a record of parameters.
8+
9+.. note::
10+
11+ This part of Rel8's API uses the ``DuplicateRecordFields`` language
12+ extension. In code that needs to use this API, you should also enable this
13+ language extension, or you may get errors about ambiguous field names.
14+
15+``DELETE``
16+----------
17+
18+To perform a ``DELETE`` statement, construct a ``Delete`` value and execute it
19+using ``delete``. ``Delete`` takes:
20+
21+``from``
22+ The ``TableSchema`` for the table to delete rows from.
23+
24+``using``
25+ This is a simple ``Query`` that forms the ``USING`` clause of the ``DELETE``
26+ statement. This can be used to join against other tables, and the results
27+ can be referenced in the ``deleteWhere`` parameter. For simple ``DELETE``\s
28+ where you don't need to do this, you can set ``using = pure ()``.
29+
30+``deleteWhere``
31+ The ``WHERE`` clause of the ``DELETE`` statement. This is a function that
32+ takes two inputs: the result of the ``using`` query, and the current value
33+ of the row.
34+
35+``returning``
36+ What to return - see :ref:`returning`.
37+
38+``UPDATE``
39+----------
40+
41+To perform a ``UPDATE`` statement, construct a ``Update`` value and execute it
42+using ``update``. ``Update`` takes:
43+
44+``target``
45+ The ``TableSchema`` for the table to update rows in.
46+
47+``from``
48+ This is a simple ``Query`` that forms the ``FROM`` clause of the ``UPDATE``
49+ statement. This can be used to join against other tables, and the results
50+ can be referenced in the ``set`` and ``updateWhere`` parameters. For simple
51+ ``UPDATE``\s where you don't need to do this, you can set ``from = pure ()``.
52+
53+``set``
54+ A row to row transformation function, indicating how to update selected rows.
55+ This function takes rows of the same shape as ``target`` but in the ``Expr``
56+ context. One way to write this function is to use record update syntax::
57+
58+ set = \from row -> row { rowName = "new name" }
59+
60+``updateWhere``
61+ The ``WHERE`` clause of the ``UPDATE`` statement. This is a function that
62+ takes two inputs: the result of the ``from`` query, and the current value of
63+ the row.
64+
65+``returning``
66+ What to return - see :ref:`returning`.
67+
68+``INSERT``
69+----------
70+
71+To perform a ``INSERT`` statement, construct a ``Insert`` value and execute it
72+using ``insert``. ``Insert`` takes:
73+
74+``into``
75+ The ``TableSchema`` for the table to insert rows into.
76+
77+``rows``
78+ The rows to insert. These are the same as ``into``, but in the ``Expr``
79+ context. You can construct rows from their individual fields::
80+
81+ rows = values [ MyTable { myTableA = lit "A", myTableB = lit 42 }
82+
83+ or you can use ``lit`` on a table value in the ``Result`` context::
84+
85+ rows = values [ lit MyTable { myTableA = "A", myTableB = 42 }
86+
87+``onConflict``
88+ What should happen if an insert clashes with rows that already exist. This
89+ corresponds to PostgreSQL's ``ON CONFLICT`` clause. You can specify:
90+
91+ ``Abort``
92+ PostgreSQL should abort the ``INSERT`` with an exception
93+
94+ ``DoNothing``
95+ PostgreSQL should not insert the duplicate rows.
96+
97+ ``DoUpdate``
98+ PostgreSQL should instead try to update any existing rows that conflict
99+ with rows proposed for insertion.
100+
101+``returning``
102+ What to return - see :ref:`returning`.
103+
104+.. _returning:
105+
106+``RETURNING``
107+-------------
108+
109+PostgreSQL has the ability to return extra information after a ``DELETE``,
110+``INSERT`` or ``UPDATE`` statement by attaching a ``RETURNING`` clause. A common
111+use of this clause is to return any automatically generated sequence values for
112+primary key columns. Rel8 supports ``RETURNING`` clauses by filling in the
113+``returning`` field and specifying a ``Projection``. A ``Projection`` is a row
114+to row transformation, allowing you to project out a subset of fields.
115+
116+For example, if we are inserting orders, we might want the order ids returned::
117+
118+ insert Insert
119+ { into = orderSchema
120+ , rows = values [ order ]
121+ , onConflict = Abort
122+ , returning = Projection orderId
123+ }
124+
125+If we don't want to return anything, we can use ``pure ()``::
126+
127+ insert Insert
128+ { into = orderSchema
129+ , rows = values [ order ]
130+ , onConflict = Abort
131+ , returning = pure ()
132+ }
133+
134+Default values
135+--------------
136+
137+It is fairly common to define tables with default values. While Rel8 does not
138+have specific functionality for ``DEFAULT``, there are a few options:
139+
140+``unsafeDefault``
141+~~~~~~~~~~~~~~~~~~~~~~~~~~~
142+
143+Rel8 does not have any special support for ``DEFAULT``. If you need to use
144+default column values in inserts, you can use ``unsafeDefault`` to
145+construct the ``DEFAULT`` expression::
146+
147+ insert Insert
148+ { into = orderSchema
149+ , rows = values [ Order { orderId = unsafeDefault, ... } ]
150+ , onConflict = Abort
151+ , returning = Projection orderId
152+ }
153+
154+.. warning::
155+ As the name suggests, this is an unsafe operation. In particular, Rel8 is not
156+ able to prove that this column does have a default value, so it may be
157+ possible to introduce a runtime error. Furthermore, ``DEFAULT`` is fairly
158+ special in SQL, and cannot be combined like other expressions. For example,
159+ the innocuous expression::
160+
161+ unsafeDefault + 1
162+
163+ will lead to a runtime crash.
164+
165+Reimplement default values in Rel8
166+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
167+
168+If you only need to access default values in Rel8, another option is to specify
169+them in Rel8, rather than in your database schema.
170+
171+.. hint::
172+ A common default value for primary keys is to use `nextval` to obtain the
173+ next value from a sequence. This can be done in Rel8 by using the ``nextval``
174+ function::
175+
176+ insert Insert
177+ { into = orderSchema
178+ , rows = values [ Order { orderId = nextval "order_id_seq", ... } ]
179+ , onConflict = Abort
180+ , returning = Projection orderId
181+ }
docs/concepts/queries.rstnew file+274
@@ -0,0 +1,274 @@
1+Writing queries with ``Query``
2+==============================
3+
4+To fetch data from a database, Rel8 allows you to write ``SELECT`` queries using
5+the ``Query`` monad. While this monad might look a little different from
6+ordinary SQL, it is equal in expressivity, but due to Haskell's ``do`` notation
7+we get to benefit from all the means of abstraction available.
8+
9+Understanding the ``Query`` monad
10+---------------------------------
11+
12+Before we look at special functions for working with ``Query``, we'll first take
13+a moment to understand how the ``Query`` monad works. First, what does the type
14+``Query a`` *mean*? To be a ``Query a`` means to be a SQL ``SELECT`` query that
15+selects rows of type ``a``. Usually ``a`` will be an instance of ``Table Expr``,
16+such as ``Expr Text``, or maybe ``BlogPostComment Expr``.
17+
18+As ``Query`` is an instance of ``Monad`` means that we already have three
19+familiar APIs to work with: ``Functor``, ``Applicative``, and ``Monad``.
20+
21+``Functor Query``
22+^^^^^^^^^^^^^^^^^
23+
24+The ``Functor`` instance gives us access to ``fmap``, and its type is::
25+
26+ fmap :: (a -> b) -> Query a -> Query b
27+
28+``fmap`` uniformly transforms rows of one type into rows of another type. In
29+SQL, this is corresponds to a *projection*. For example, if we have a ``Query
30+(User Expr)``, we might do ``fmap userId`` to transform this into a ``Query
31+(Expr UserId)``.
32+
33+``Applicative Query``
34+^^^^^^^^^^^^^^^^^^^^^
35+
36+The ``Applicative`` instance for ``Query`` gives us::
37+
38+ pure :: a -> Query a
39+ (<*>) :: Query (a -> b) -> Query a -> Query b
40+
41+``pure`` constructs a ``Query`` that returns exactly one row - a row containing
42+the ``a`` that was given. This might seem fairly pointless, but it's an
43+important ``Query`` when compared with ``(<*>)``. The ``<*>`` combines two
44+``Query``\s by taking their *cartesian product*, followed by a projection that
45+combines each row into a new row.
46+
47+One example of using the ``Applicative`` operators is to combine two ``Query``\s
48+into a tuple::
49+
50+ pure (,) <*> queryA <*> queryB
51+
52+``Monad Query``
53+^^^^^^^^^^^^^^^
54+
55+The final type class to discuss is ``Monad Query``. ``Monad Query`` has two
56+methods::
57+
58+ return :: a -> Query a
59+ (>>=) :: Query a -> (a -> Query b) -> Query b
60+
61+``return`` is the same ``pure``, so we won't discuss this further. The much more
62+interesting operation is ``>>=`` - commonly referred to as "bind". This operator
63+allows you to *extend* a ``Query`` with a new query. In SQL this is also similar
64+to a cartesian product, but uses the ``LATERAL`` modifier to allow the second
65+query to refer to columns from the first.
66+
67+This extension operator allows you to expand each row in the first query into
68+zero, one, or many rows, according to the given function. For example, if we
69+have a database of orders, we might write::
70+
71+ getAllOrders >>= \order -> getUserById (orderUserId order)
72+
73+This ``Query`` will return, for each ``Order``, the ``User`` who placed that
74+order. In this case, this is a one-to-one relationship, so we get back exactly
75+as many rows as there are orders.
76+
77+Going in the other direction, we have::
78+
79+ getAllUsers >>= \user -> getOrdersForUser (userId user)
80+
81+This is a different query, as we start by fetching all ``User``\s, and for each
82+user find all ``Order``\s they have placed. This ``Query`` has a different
83+cardinality, as we're following a one-to-many relationship: any ``User`` may
84+have zero, one, or many orders.
85+
86+Haskell has special syntax for working with monads - ``do`` notation. ``do``
87+notation allows you to write these queries in a simpler form, where we don't
88+have to introduce functions. Expanding on the latter query, we could write::
89+
90+ do user <- getAllUsers
91+ order <- getOrdersForUser user
92+ return (user, order)
93+
94+Now we have a query that, for each ``User``, fetches all orders for that user.
95+The final ``return`` means that for each ``User`` and ``Order``, we'll return a
96+single row.
97+
98+Selecting rows from tables
99+--------------------------
100+
101+With the more theoretical side of ``Query`` considered, we can start looking at
102+the more pragmatic side, and how ``Query`` can express some common SQL idioms.
103+
104+First, one of the most common operations is to select all rows from a *base
105+table*. In SQL, this is a ``SELECT * FROM x`` query, and in Rel8 we use ``each``
106+with a ``TableSchema``.
107+
108+Limit and offset
109+----------------
110+
111+The SQL ``LIMIT`` and ``OFFSET`` keywords are available in Rel8 as ``limit``
112+and ``offset``. Note that, like SQL, the order of these operations matters.
113+Usually, the correct thing to do is to first apply an offset with ``offset``,
114+and then use ``limit`` to limit the number of rows returned::
115+
116+ limit n . offset m . orderBy anOrdering
117+
118+These operations are similar to Haskell's ``take`` and ``drop`` operations.
119+
120+Filtering queries
121+-----------------
122+
123+Rel8 offers a few different ways to filter the rows selected by a query.
124+Perhaps the most familiar operation is to apply a ``WHERE`` clause to a query.
125+In Rel8, this is done using ``where_``, which takes any ``Expr Bool``, and
126+returns rows where that ``Expr`` is true. For example, to select all public
127+blog posts, we could write::
128+
129+ blogPost <- each blogPostSchema
130+ where_ $ blogPostIsPublic blogPost
131+
132+An alternative way to write ``WHERE`` clauses is to use ``filter``. This
133+operator is similar to the ``guard`` function in ``Control.Monad``, but also
134+returns the tested row. This allows us to easily chain a filtering operation on
135+a query. The above query could thus be written as::
136+
137+ blogPost <- filter blogPostIsPublic =<< each blogPostSchema
138+
139+``where_`` and ``filter`` allow you to filter rows based on an expression, but
140+sometimes we want to filter based on another query. For this, Rel8 offers
141+``present`` and ``absent``. For example, if all blog posts have a
142+list of tags, we could use ``present`` to find all blog posts that have been
143+tagged as "Haskell"::
144+
145+ blogPost <- each blogPostSchema
146+ present do
147+ filter (("Haskell" ==.) . tagName) =<< tagFromBlogPost blogPost
148+
149+Notice that this example uses ``present`` with a query that itself uses
150+``filter``. For each blog post, ``present`` causes that row to be selected
151+only if the associated query finds a tag for that blog post with the ``tagName``
152+"Haskell".
153+
154+Like ``filter`` there is also a chaining variant of ``present`` - ``with``.
155+We could rewrite the above query using ``with`` as::
156+
157+ haskellBlogPost <-
158+ each blogPostSchema >>=
159+ with (filter (("Haskell" ==.) . tagName) <=< tagFromBlogPost)
160+
161+Inner joins
162+-----------
163+
164+Inner joins are SQL queries of the form ``SELECT .. FROM x JOIN y ON ..``. Rel8
165+doesn't offer a special function for these queries, as the same query can be
166+expressed by selecting from two tables (this is called taking the *cartesian
167+product* of two queries) and then filtering the result.
168+
169+If we wanted to join each blog post with the author of the blog post, we would
170+write the SQL::
171+
172+ SELECT * FROM blog_post JOIN author ON author.id = blog_post.id
173+
174+The alternative way to write this query with ``WHERE`` is::
175+
176+ SELECT * FROM blog_post, author WHERE author.id = blog_post.id
177+
178+and this query can be written in Rel8 as::
179+
180+ blogPost <- each blogPostSchema
181+ author <- each authorSchema
182+ where_ $ blogPostAuthorId blogPost ==. authorId author
183+
184+.. hint::
185+
186+ A good pattern to adopt is to abstract out these joins as functions. A
187+ suggested way to write the above would be to extract out an "author for blog
188+ post" function::
189+
190+ blogPost <- each blogPostSchema
191+ author <- authorForBlogPost blogPost
192+
193+ where::
194+
195+ authorForBlogPost :: BlogPost Expr -> Query (Author Expr)
196+ authorForBlogPost blogPost =
197+ filter ((blogPostAuthorId blogPost ==.) . authorId) =<<
198+ each authorSchema
199+
200+ While this is a little more code over all, in our experience this style
201+ dramatically increases the readability of queries using joins.
202+
203+Left (outer) joins with ``optional``
204+------------------------------------
205+
206+A left join is like an inner join, but allows for the possibility of the join to
207+"fail". You use left joins when you want to join optional information against a
208+row.
209+
210+In Rel8, a ``LEFT JOIN`` is introduced by converting an inner join with
211+``optional``. While this approach might seem a little foreign at first, it has a
212+strong similarity with the ``Control.Applicative.optional`` function, and allows
213+you to reuse previous code.
214+
215+To see an example of this, let's assume that we want to get the latest comment
216+for each blog post. Not all blog posts are popular though, so some blog posts
217+might have no comment at all. To write this in Rel8, we could write::
218+
219+ blogPost <- each blogPostSchema
220+
221+ latestComment <-
222+ optional $ limit 1 $
223+ orderBy (commentCreatedAt >$< desc) $
224+ commentsForBlogPost blogPost
225+
226+``optional`` will transform a ``Query a`` into a ``Query (MaybeTable a)``.
227+``MaybeTable`` is similar to the normal ``Maybe`` data type in Haskell, and
228+represents the choice between a ``justTable x`` and a ``nothingTable`` (like
229+``Just x`` and ``Nothing``, respectively). When you execute a query containing
230+``MaybeTable x`` with ``select``, Rel8 will return ``Maybe x``. ``MaybeTable``
231+comes with a library of routines, similar to the functions that can be used to
232+operate on ``Maybe``. For more details, see the API documentation.
233+
234+.. hint::
235+
236+ ``optional`` converts an inner join into a ``LEFT JOIN``, but you can also go
237+ the other way - and turn a ``LEFT JOIN`` back into an inner join! To do this,
238+ you can use ``catMaybeTable``, which will select only the rows when the left
239+ join was successful.
240+
241+Ordering results
242+----------------
243+
244+Rel8 supports ordering the results returned by a ``Query``, using SQL's ``ORDER
245+BY`` syntax. To specify an ordering, you use ``orderBy`` and supply an
246+appropriate ``Order`` value.
247+
248+An ``Order`` is built by combining the order of individual columns, each of
249+which can be either ascending or descending. To order a single column, you
250+combine ``asc`` or ``desc`` with ``Order``\s *contravariant* interface. For
251+example, if we have a table with a ``orderId`` column, we can order a ``Query
252+(Order Expr)`` by ``orderId`` with::
253+
254+ orderBy (orderId >$< asc)
255+
256+To order by multiple columns, combine the individual orders with ``Order``\s
257+``Monoid`` instance. We could extend the above example to order by the order
258+date first (with the most recent orders first) with::
259+
260+ orderBy (mconcat [orderDate >$< desc, orderId >$< asc])
261+
262+Aggregating queries
263+-------------------
264+
265+.. todo::
266+
267+ Write this
268+
269+Set operations
270+--------------
271+
272+.. todo::
273+
274+ Write this
docs/concepts/tables.rstnew file+60
@@ -0,0 +1,60 @@
1+Tables
2+======
3+
4+So far we've seen that ``DBType`` bridges Haskell types to database types, and
5+``Expr`` lets us write SQL expressions using these types. The next concept is to
6+understand how tables are mapped into Rel8.
7+
8+In Rel8, we understand a table to be a list of columns. Each column has some
9+associated metadata - a column has a type, but it also has information as to
10+whether it can store ``null``, the name of the column, and whether this column
11+has a default value. All of this metadata can be configured when you define
12+custom table types, but first we'll look at some built in tables.
13+
14+``Expr`` is a single-column table
15+---------------------------------
16+
17+Any time you have an ``Expr``, you also have a table. All ``Expr``\s are tables
18+that consist of exactly one column. This means that whenever a table is
19+expected, you can usually use an ``Expr`` as well.
20+
21+Tuples combine tables
22+---------------------
23+
24+You can use Haskell's normal tuple syntax to combine tables into larger tables.
25+Now that we know that an ``Expr`` is a table with one column, we can use tuples
26+to build larger tables. For example, if we have ``userId :: Expr UserId`` and a
27+``name :: Expr Text``, we can pair these together as ``(userId, name) :: (Expr
28+UserId, Expr Text)``.
29+
30+Rel8 supports tuples with two, three, four and five elements. Beyond that, we
31+suggest writing a custom table type (though you can also nest tuples).
32+
33+Custom table types
34+------------------
35+
36+The primary way to define a table in Rel8 is to use the higher-kinded data
37+pattern. Rel8 advocates this system because it means you can define your data
38+type once, but use it in the context of Haskell expressions (for example, to
39+serialize it as JSON to use as a REST API call response type), and also within
40+Rel8 queries. This allows developers to share their understanding of a type in
41+multiple domains, while also reducing the amount of code that has to be written
42+and maintained.
43+
44+To define a custom table using this pattern, you define a Haskell data type that
45+has a single parameter (conventionally called ``f``). Next, we suggest using
46+record syntax to define the fields of your data type, and for each field use the
47+``Column`` type family to define the type of the column. Once all fields have
48+been defined, you can bridge this type with Rel8 by deriving ``Generic`` and
49+``Rel8able`` instance.
50+
51+A typical table definition might look like this::
52+
53+ data User f = User
54+ { userId :: Column f UserId
55+ , userName :: Column f Text
56+ , userCreatedAt :: Column f UTCTime
57+ , userEmail :: Column f (Maybe EmailAddress)
58+ }
59+ deriving stock (Generic)
60+ deriving anyclass (Rel8able)
docs/conf.pynew file+36
@@ -0,0 +1,36 @@
1+import sys
2+import os
3+import sphinx_rtd_theme
4+
5+# Support for :base-ref:, etc.
6+sys.path.insert(0, os.path.abspath('.'))
7+
8+version = "1.0.0"
9+
10+extensions = ['sphinx.ext.extlinks', 'sphinx.ext.todo', 'sphinx_rtd_theme']
11+
12+templates_path = ['_templates']
13+source_suffix = '.rst'
14+source_encoding = 'utf-8-sig'
15+master_doc = 'index'
16+
17+project = u'Rel8'
18+copyright = u'2021 CircuitHub'
19+release = version
20+
21+highlight_language = 'haskell'
22+primary_domain = 'haskell'
23+
24+exclude_patterns = ['.build', "*.gen.rst"]
25+
26+html_theme = 'sphinx_rtd_theme'
27+html_theme_options = {
28+ 'logo_only': True,
29+ 'navigation_depth': 5,
30+}
31+html_context = {}
32+
33+# on_rtd is whether we are on readthedocs.org, this line of code grabbed from docs.readthedocs.org
34+on_rtd = os.environ.get('READTHEDOCS', None) == 'True'
35+
36+todo_include_todos = True
docs/cookbook.rstnew file+169
@@ -0,0 +1,169 @@
1+Cookbook
2+========
3+
4+This cookbook exists to help you easily form Rel8 queries. It's main purpose is
5+to help those familiar with SQL to translate their queries into Rel8
6+``Query``\s.
7+
8+``SELECT * FROM table``
9+-----------------------
10+
11+To select from a table, use ``each``.
12+
13+Inner joins
14+-----------
15+
16+To perform an inner join against two queries, use ``where_`` with a join
17+condition. For example, the following SQL:
18+
19+.. code-block:: sql
20+
21+ SELECT * FROM table_a JOIN table_b ON table_a.x = table_b.y
22+
23+can be written as::
24+
25+ myQuery = do
26+ a <- each tableA
27+ b <- each tableB
28+ where_ $ tableAX a ==. tableBY b
29+
30+Left (outer) joins
31+------------------
32+
33+A ``LEFT JOIN`` query is performed by using ``optional``.
34+
35+For example, the query:
36+
37+.. code-block:: sql
38+
39+ SELECT * FROM table_a LEFT JOIN table_b ON table_a.x = table_b.y
40+
41+can be written as::
42+
43+ myQuery = do
44+ a <- each tableA
45+
46+ maybeB <- optional do
47+ b <- each tableB
48+ where_ $ tableAX a ==. tableBY b
49+
50+ return (a, maybeB)
51+
52+Note that ``maybeB`` here will be a ``MaybeTable``, which is the Rel8
53+``Query``-equivalent of ``Maybe``. This allows you to observe if a left join
54+has succeeded or failed.
55+
56+Ordering results
57+----------------
58+
59+A ``Query`` by default has no ordering - just like in SQL. If you rows back in
60+a certain order, you can use ``orderBy`` with an ``Order``.
61+
62+For example, the query:
63+
64+.. code-block:: sql
65+
66+ SELECT * FROM my_table ORDER BY my_table.id ASC, my_table.x DESC NULLS FIRST
67+
68+can be written as::
69+
70+ myQuery =
71+ orderBy (mconcat [ myTableId >$< asc, myTableX >$< nullsFirst desc ]) $
72+ each myTableSchema
73+
74+Note that we use ``>$<`` (from ``Data.Functor.Contravariant``) to select table
75+columns, and we can use ``mconcat`` to combine orderings.
76+
77+If all columns of a table have an ordering, you can also use ``ascTable`` and
78+``descTable``. For example::
79+
80+ myQuery = orderBy ascTable $ each myTableSchema
81+
82+Aggregations
83+------------
84+
85+Aggregations in Rel8 work by using ``aggregate``, which takes a ``Query
86+(Aggregate a)`` and gives you back a ``Query a``.
87+
88+The following query:
89+
90+.. code-block:: sql
91+
92+ SELECT sum(foo), count(distinct bar) FROM table_a
93+
94+can be written as::
95+
96+ myQuery = aggregate do
97+ a <- each tableA
98+ return $ liftF2 (,) (sum (foo a)) (countDistinct (bar a))
99+
100+where ``liftF2`` comes from ``Data.Functor.Apply`` from the ``semigroupoids``
101+library.
102+
103+Combining aggregations
104+----------------------
105+
106+As ``Aggregate`` is an instance of ``Apply`` (which is very similar to
107+``Applicative``), individual aggregations can be combined. For example, one way
108+to take the average rating would be to write the query:
109+
110+.. code-block:: sql
111+
112+ SELECT sum(rating.score) / count(rating.score) FROM rating
113+
114+In Rel8, we can write this as::
115+
116+ myQuery = aggregate do
117+ rating <- each ratingSchema
118+ return $ liftF2 (/) (sum (score rating)) (count (score rating))
119+
120+You can also use ``RebindableSyntax`` and ``ApplicativeDo``::
121+
122+ {-# language ApplicativeDo, RebindableSyntax #-}
123+
124+ import Data.Functor.Apply ((<.>))
125+
126+ myQuery = aggregate do
127+ rating <- each ratingSchema
128+ return do
129+ scoreSum <- sum (score rating)
130+ numberOfRatings <- count (score rating)
131+ return (scoreSum / numberOfRatings)
132+ where (<*>) = (<.>)
133+
134+For large aggregations, this can often make queries easier to read.
135+
136+Tree-like queries
137+-----------------
138+
139+Rel8 has a fairly unique feature in that it's able to return not just lists of
140+rows, but can also return *tree*\s.
141+
142+To understand what this means, we'll consider a small example query for blog
143+posts. We want our query to return:
144+
145+1. The latest 5 blog posts that have at least one tag each.
146+2. For each blog post, all tags.
147+3. For each blog post, the latest 3 comments if they exist.
148+
149+In Rel8, we can write this query as::
150+
151+ latestBlogPosts = do
152+ post <- each postSchema
153+
154+ -- Returns a `NonEmptyTable a` which ends up as a `Data.List.NonEmpty a` after the query is run
155+ tags <- some $ do
156+ tag <- each tagSchema
157+ where_ (tagPostId tag ==. postId post)
158+ return (tagName tag)
159+
160+ -- Returns a `ListTable a` which ends up as a `[a]` after the query is run
161+ latestComments <-
162+ many $
163+ limit 3 $
164+ orderBy (commentCreatedAt >$< desc) do
165+ comment <- each commentSchema
166+ where_ (commentPostId comment ==. postId post)
167+
168+ return (post, tags, latestComments)
169+
docs/index.rstnew file+53
@@ -0,0 +1,53 @@
1+Welcome to Rel8!
2+================
3+
4+Welcome to Rel8! Rel8 is a Haskell library for interacting with PostgreSQL
5+databases, built on top of the fantastic `Opaleye
6+<https://hackage.haskell.org/package/opaleye>`_ library.
7+
8+The main objectives of Rel8 are:
9+
10+* *Conciseness*: Users using Rel8 should not need to write boiler-plate code.
11+ By using expressive types, we can provide sufficient information for the
12+ compiler to infer code whenever possible.
13+
14+* *Inferrable*: Despite using a lot of type level magic, Rel8 aims to have
15+ excellent and predictable type inference.
16+
17+* *Familiar*: writing Rel8 queries should feel like normal Haskell programming.
18+
19+.. toctree::
20+ :caption: Getting Started
21+ :maxdepth: 2
22+
23+ tutorial
24+
25+.. toctree::
26+ :caption: Rel8 concepts
27+ :maxdepth: 2
28+
29+ concepts/dbtype
30+ concepts/expr
31+ concepts/tables
32+ concepts/queries
33+ concepts/insert
34+
35+.. toctree::
36+ :caption: Tips and tricks
37+ :maxdepth: 1
38+
39+ cookbook
40+
41+
42+More Resources
43+==============
44+
45+* The `Haskell API documentation <https://hackage.haskell.org/package/rel8>`_
46+ describes how individual functions are types are to be used.
47+
48+* If you have a question about how to use Rel8, feel free to open a `GitHub
49+ discussion <https://github.com/circuithub/rel8/discussions>`_.
50+
51+* If you think you've found a bug, confusing behavior, or have a feature
52+ request, please raise an issue at `Rel8's issue tracker
53+ <https://github.com/circuithub/rel8>`_.
docs/requirements.txtnew file+4
@@ -0,0 +1,4 @@
1+docutils == 0.16.*
2+sphinx == 3.5.*
3+sphinx_rtd_theme
4+
docs/tutorial.rstnew file+387
@@ -0,0 +1,387 @@
1+.. highlight:: haskell
2+
3+Getting Started
4+===============
5+
6+In this section, we'll take a look at using Rel8 to work with a small database
7+for Haskell packages. We'll take a look at idiomatic usage of Rel8, mapping
8+tables to Haskell, and then look at writing some simple queries.
9+
10+Before we get started, we'll be using the following language extensions and
11+imports throughout this guide::
12+
13+ {-# language BlockArguments #-}
14+ {-# language DeriveAnyClass #-}
15+ {-# language DeriveGeneric #-}
16+ {-# language DerivingStrategies #-}
17+ {-# language DerivingVia #-}
18+ {-# language DuplicateRecordFields #-}
19+ {-# language GeneralizedNewtypeDeriving #-}
20+ {-# language OverloadedStrings #-}
21+ {-# language StandaloneDeriving #-}
22+ {-# language TypeApplications #-}
23+ {-# language TypeFamilies #-}
24+
25+ import Prelude
26+ import Rel8
27+
28+The Example Schema
29+------------------
30+
31+Before we start writing any Haskell, let's take a look at the schema we'll work
32+with. The `author` table has three columns:
33+
34++-----------------+-------------+----------+
35+| Column Name | Type | Nullable |
36++=================+=============+==========+
37+| ``author_id`` | ``integer`` | not null |
38++-----------------+-------------+----------+
39+| ``name`` | ``text`` | not null |
40++-----------------+-------------+----------+
41+| ``url`` | ``text`` | |
42++-----------------+-------------+----------+
43+
44+and the `project` table has two:
45+
46++-----------------+-------------+----------+
47+| Column Name | Type | Nullable |
48++=================+=============+==========+
49+| ``author_id`` | ``integer`` | not null |
50++-----------------+-------------+----------+
51+| ``name`` | ``text`` | not null |
52++-----------------+-------------+----------+
53+
54+A ``project`` always has an ``author``, but not all ``author``\s have projects.
55+Each ``author`` has a name and (maybe) an associated website, and each project
56+has a name.
57+
58+Mapping Schemas to Haskell
59+--------------------------
60+
61+Now that we've seen our schema, we can begin writing a mapping in Rel8. The
62+idiomatic way to map a table is to use a record that is parameterised what Rel8
63+calls an *interpretation functor*, and to define each field with ``Column``.
64+For this type to be usable with Rel8 we need it to be an instance of
65+``Rel8able``, which can be derived with a combination of ``DeriveAnyClass`` and
66+``DeriveGeneric`` language extensions.
67+
68+Following these steps for ``author``, we have::
69+
70+ data Author f = Author
71+ { authorId :: Column f Int64
72+ , name :: Column f Text
73+ , url :: Column f (Maybe Text)
74+ }
75+ deriving stock (Generic)
76+ deriving anyclass (Rel8able)
77+
78+This is a perfectly reasonable definition, but cautious readers might notice a
79+problem - in particular, with the type of the ``authorId`` field. While
80+``Int64`` is correct, it's not the best type. If we had other identifier types
81+in our project, it would be too easy to accidentally mix them up and create
82+nonsensical joins. As Haskell programmers, we often solve this problem by
83+creating ``newtype`` wrappers, and we can also use this technique with Rel8::
84+
85+ newtype AuthorId = AuthorId { toInt64 :: Int64 }
86+ deriving newtype (DBEq, DBType, Eq, Show)
87+
88+Now we can write our final schema mapping. First, the ``author`` table::
89+
90+ data Author f = Author
91+ { authorId :: Column f AuthorId
92+ , authorName :: Column f Text
93+ , authorUrl :: Column f (Maybe Text)
94+ }
95+ deriving stock (Generic)
96+ deriving anyclass (Rel8able)
97+
98+And similarly, the ``project`` table::
99+
100+ data Project f = Project
101+ { projectAuthorId :: Column f AuthorId
102+ , projectName :: Column f Text
103+ }
104+ deriving stock (Generic)
105+ deriving anyclass (Rel8able)
106+
107+To show query results in this documentation, we'll also need ``Show`` instances:
108+Unfortunately these definitions look a bit scary, but they are essentially just
109+``deriving (Show)``::
110+
111+ deriving stock instance f ~ Result => Show (Author f)
112+ deriving stock instance f ~ Result => Show (Project f)
113+
114+These data types describe the structural mapping of the tables, but we also
115+need to specify a ``TableSchema`` for each table. A ``TableSchema`` contains
116+the name of the table and the name of all columns in the table, which will
117+ultimately allow us to ``SELECT`` and ``INSERT`` rows for these tables.
118+
119+To define a ``TableSchema``, we just need to fill construct appropriate
120+``TableSchema`` values. When it comes to the ``tableColumns`` field, we
121+construct values of our data types above, and set each field to the name of the
122+column that it maps to.
123+
124+First, ``authorSchema`` describes the column names of the ``author`` table when
125+associated with the ``Author`` type::
126+
127+ authorSchema :: TableSchema (Author Name)
128+ authorSchema = TableSchema
129+ { name = "author"
130+ , schema = Nothing
131+ , columns = Author
132+ { authorId = "author_id"
133+ , authorName = "name"
134+ , authorUrl = "url"
135+ }
136+ }
137+
138+And likewise for ``project`` and ``Project``::
139+
140+ projectSchema :: TableSchema (Project Name)
141+ projectSchema = TableSchema
142+ { name = "project"
143+ , schema = Nothing
144+ , columns = Project
145+ { projectAuthorId = "author_id"
146+ , projectName = "name"
147+ }
148+ }
149+
150+There is also some generics machinery available if you want to grab the field
151+information from your ``Rel8able`` type::
152+
153+ projectSchema :: TableSchema (Project Name)
154+ projectSchema = TableSchema
155+ { name = "project"
156+ , schema = Nothing
157+ , columns = namesFromLabels @(Project Name)
158+ }
159+
160+This will create a ``TableSchema`` for ``Project`` where every column name
161+corresponds exactly to the name of the field. If you need more flexibility, you
162+can use ``namesFromLabelsWith``, which takes a transformation function.
163+
164+.. note::
165+
166+ You might be wondering why this information isn't in the definitions of
167+ ``Author`` and ``Project`` above. Rel8 decouples ``TableSchema`` from the data
168+ types themselves, as not all tables you define will necessarily have a schema.
169+ For example, Rel8 allows you to define helper types to simplify the types of
170+ queries - these tables only exist at query time, but there is no corresponding
171+ base table. We'll see more on this idea later!
172+
173+With these table definitions, we can now start writing some queries!
174+
175+Writing Queries
176+---------------
177+
178+Simple Queries
179+~~~~~~~~~~~~~~
180+
181+First, we'll take a look at ``SELECT`` statements - usually the bulk of most
182+database heavy applications.
183+
184+In Rel8, ``SELECT`` statements are built using the ``Query`` monad. You can
185+think of this monad like the ordinary ``[]`` (List) monad - but this isn't
186+required knowledge.
187+
188+To start, we'll look at one of the simplest queries possible - a basic ``SELECT
189+* FROM`` statement. To select all rows from a table, we use ``each``, and
190+supply a ``TableSchema``. So to select all ``project`` rows, we can write::
191+
192+ >>> :t each projectSchema
193+ each projectSchema :: Query (Project Expr)
194+
195+Notice that ``each`` gives us a ``Query`` that yields ``Project Expr`` rows. To
196+see what this means, let's have a look at a single field of a ``Project Expr``::
197+
198+ >>> let aProjectExpr = undefined :: Project Expr
199+ >>> :t projectAuthorId aProjectExpr
200+ projectAuthorId aProjectExpr :: Expr AuthorId
201+
202+Recall we defined ``projectAuthorId`` as ``Column f AuthorId``. Now we have
203+``f`` is ``Expr``, and ``Column Expr AuthorId`` reduces to ``Expr AuthorId``.
204+We'll see more about ``Expr`` soon, but you can think of ``Expr a`` as "SQL
205+expressions of type ``a``\".
206+
207+To execute this ``Query``, we pass it to ``select``. This function takes both a
208+database connection (which can be obtained using hasql's ``acquire`` function),
209+and the ``Query`` to run::
210+
211+ >>> Right conn <- acquire "user=postgres"
212+ >>> :t select conn (each projectSchema)
213+ select conn (each projectSchema) :: MonadIO m => m [Project Result]
214+
215+When we ``select`` things containing ``Expr``\s, Rel8 builds a new response
216+table with the ``Result`` interpretation. This means you'll get back plain
217+Haskell values. Studying ``projectAuthorId`` again, we have::
218+
219+ >>> let aProjectResult = undefined :: Project Result
220+ >>> :t projectAuthorId aProjectResult
221+ projectAuthorId aProjectResult :: AuthorId
222+
223+Here ``Column Result AuthorId`` reduces to just ``AuthorId``, with no
224+wrappping type at all.
225+
226+Putting this all together, we can run our first query::
227+
228+ >>> select conn (each projectSchema) >>= mapM_ print
229+ Project {projectAuthorId = 1, projectName = "rel8"}
230+ Project {projectAuthorId = 2, projectName = "aeson"}
231+ Project {projectAuthorId = 2, projectName = "text"}
232+
233+We now know that ``each`` is the equivalent of a ``SELECT *`` query, but
234+sometimes we're only interested in a subset of the columns of a table. To
235+restrict the returned columns, we can specify a projection by using ``Query``\s
236+``Functor`` instance::
237+
238+ >>> select conn $ projectName <$> each projectSchema
239+ ["rel8","aeson","text"]
240+
241+Joins
242+~~~~~
243+
244+Another common operation in relational databases is to take the ``JOIN`` of
245+multiple tables. Rel8 doesn't have a specific join operation, but we can
246+recover the functionality of a join by selecting all rows of two tables, and
247+then using ``where_`` to filter them.
248+
249+To see how this works, first let's look at taking the product of two tables.
250+We can do this by simply calling ``each`` twice, and then returning a tuple of
251+their results::
252+
253+ >>> :{
254+ mapM_ print =<< select conn do
255+ author <- each authorSchema
256+ project <- each projectSchema
257+ return (projectName project, authorName author)
258+ :}
259+ ("rel8","Ollie")
260+ ("rel8","Bryan O'Sullivan")
261+ ("rel8","Emily Pillmore")
262+ ("aeson","Ollie")
263+ ("aeson","Bryan O'Sullivan")
264+ ("aeson","Emily Pillmore")
265+ ("text","Ollie")
266+ ("text","Bryan O'Sullivan")
267+ ("text","Emily Pillmore")
268+
269+This isn't quite right, though, as we have ended up pairing up the wrong
270+projects and authors. To fix this, we can use ``where_`` to restrict the
271+returned rows. We could write::
272+
273+ select conn $ do
274+ author <- each authorSchema
275+ project <- each projectSchema
276+ where_ $ projectAuthorId project ==. authorId author
277+ return (project, author)
278+
279+but doing this every time you need a join can obscure the meaning of the
280+query you're writing. A good practice is to introduce specialised functions
281+for the particular joins in your database. In our case, this would be::
282+
283+ projectsForAuthor :: Author Expr -> Query (Project Expr)
284+ projectsForAuthor a = each projectSchema >>= filter \p ->
285+ projectAuthorId p ==. authorId a
286+
287+Our final query is then::
288+
289+ >>> :{
290+ mapM_ print =<< select conn do
291+ author <- each authorSchema
292+ project <- projectsForAuthor author
293+ return (projectName project, authorName author)
294+ :}
295+ ("rel8","Ollie")
296+ ("aeson","Bryan O'Sullivan")
297+ ("text","Bryan O'Sullivan")
298+
299+Left Joins
300+~~~~~~~~~~
301+
302+Rel8 is also capable of performing ``LEFT JOIN``\s. To perform ``LEFT JOIN``\s,
303+we follow the same approach as before, but use the ``optional`` query
304+transformer to allow for the possibility of the join to fail.
305+
306+In our test database, we can see that there's another author who we haven't
307+seen yet::
308+
309+ >>> select conn $ authorName <$> each authorSchema
310+ ["Ollie","Bryan O'Sullivan","Emily Pillmore"]
311+
312+Emily wasn't returned in our earlier query because - in our database - she
313+doesn't have any registered projects. We can account for this partiality in our
314+original query by wrapping the ``projectsForAuthor`` call with ``optional``::
315+
316+ >>> :{
317+ mapM_ print =<< select conn do
318+ author <- each authorSchema
319+ mproject <- optional $ projectsForAuthor author
320+ return (authorName author, projectName <$> mproject)
321+ :}
322+ ("Ollie",Just "rel8")
323+ ("Bryan O'Sullivan",Just "aeson")
324+ ("Bryan O'Sullivan",Just "text")
325+ ("Emily Pillmore",Nothing)
326+
327+
328+Aggregation
329+~~~~~~~~~~~
330+
331+Aggregations are operations like ``sum`` and ``count`` - operations that reduce
332+multiple rows to single values. To perform aggregations in Rel8, we can use the
333+``aggregate`` function, which takes a ``Query`` of aggregated expressions, runs
334+the aggregation, and returns aggregated rows.
335+
336+To start, let's look at a simple aggregation that tells us how many projects
337+exist:
338+
339+.. todo::
340+
341+ >>> error "TODO"
342+
343+Rel8 is also capable of aggregating multiple rows into a single row by
344+concatenating all rows as a list. This aggregation allows us to break free of
345+the row-orientated nature of SQL and write queries that return tree-like
346+structures. Earlier we saw an example of returning authors with their projects,
347+but the query didn't do a great job of describing the one-to-many relationship
348+between authors and their projects.
349+
350+Let's look again at a query that returns authors and their projects, and
351+focus on the /type/ of that query::
352+
353+ projectsForAuthor a = each projectSchema >>= filter \p ->
354+ projectAuthorId p ==. authorId a
355+
356+ let authorsAndProjects = do
357+ author <- each authorSchema
358+ project <- projectsForAuthor author
359+ return (author, project)
360+ where
361+
362+ >>> :t select conn authorsAndProjects
363+ select conn authorsAndProjects
364+ :: MonadIO m => m [(Author Result, Project Result)]
365+
366+
367+Our query gives us a single list of pairs of authors and projects. However,
368+with our domain knowledge of the schema, this isn't a great type - what we'd
369+rather have is a list of pairs of authors and /lists/ of projects. That is,
370+what we'd like is::
371+
372+ [(Author Result, [Project Result])]
373+
374+This would be a much better type! Rel8 can produce a query with this type by
375+simply wrapping the call to ``projectsForAuthor`` with either ``some`` or
376+``many``. Here we'll use ``many``, which allows for the possibility of an
377+author to have no projects::
378+
379+ >>> :{
380+ mapM_ print =<< select conn do
381+ author <- each authorSchema
382+ projectNames <- many $ projectName <$> projectsForAuthor author
383+ return (authorName author, projectNames)
384+ :}
385+ ("Ollie",["rel8"])
386+ ("Bryan O'Sullivan",["aeson","text"])
387+ ("Emily Pillmore",[])
jobs.nixdeleted−5
@@ -1,5 +0,0 @@
1−let rel8 = (import ./.).hsPkgs.rel8;
2−in {
3− rel8 = rel8.components.library;
4− tests = rel8.checks.tests;
5−}
nix/sources.json+36−36
@@ -1,38 +1,38 @@
11{
2− "haskell.nix": {
3− "branch": "circuithub",
4− "description": "Alternative Haskell Infrastructure for Nixpkgs",
5− "homepage": "https://input-output-hk.github.io/haskell.nix",
6− "owner": "circuithub",
7− "repo": "haskell.nix",
8− "rev": "2902f9b49484a87afb0e1a33b1d88a2c7b8ca0a0",
9− "sha256": "0a01g5b46z5yaf2mnl415hc4lciwiyqhj22qhgwgwd261w4068iy",
10− "type": "tarball",
11− "url": "https://github.com/circuithub/haskell.nix/archive/2902f9b49484a87afb0e1a33b1d88a2c7b8ca0a0.tar.gz",
12− "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
13− },
14− "niv": {
15− "branch": "master",
16− "description": "Easy dependency management for Nix projects",
17− "homepage": "https://github.com/nmattia/niv",
18− "owner": "nmattia",
19− "repo": "niv",
20− "rev": "ba57d5a29b4e0f2085917010380ef3ddc3cf380f",
21− "sha256": "1kpsvc53x821cmjg1khvp1nz7906gczq8mp83664cr15h94sh8i4",
22− "type": "tarball",
23− "url": "https://github.com/nmattia/niv/archive/ba57d5a29b4e0f2085917010380ef3ddc3cf380f.tar.gz",
24− "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
25− },
26− "nixpkgs": {
27− "branch": "nixos-20.09",
28− "description": "Nix Packages collection",
29− "homepage": null,
30− "owner": "nixos",
31− "repo": "nixpkgs",
32− "rev": "6e7f25001fe6874f7ae271891f709bbf50a22c45",
33− "sha256": "1x04j4351pqiqbpkq6g308mxcvb5aqnwv8l2vmlxkgvq5phzky7z",
34− "type": "tarball",
35− "url": "https://github.com/nixos/nixpkgs/archive/6e7f25001fe6874f7ae271891f709bbf50a22c45.tar.gz",
36− "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
37− }
2+ "haskell.nix": {
3+ "branch": "master",
4+ "description": "Alternative Haskell Infrastructure for Nixpkgs",
5+ "homepage": "https://input-output-hk.github.io/haskell.nix",
6+ "owner": "input-output-hk",
7+ "repo": "haskell.nix",
8+ "rev": "0837156c56cb5350dd9bd84eb424187e00aa1e8a",
9+ "sha256": "1djmv5a0vfj78csw2cad6nicrs8iqrp928b9b3v4h7lwwhhzliwl",
10+ "type": "tarball",
11+ "url": "https://github.com/input-output-hk/haskell.nix/archive/0837156c56cb5350dd9bd84eb424187e00aa1e8a.tar.gz",
12+ "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
13+ },
14+ "niv": {
15+ "branch": "master",
16+ "description": "Easy dependency management for Nix projects",
17+ "homepage": "https://github.com/nmattia/niv",
18+ "owner": "nmattia",
19+ "repo": "niv",
20+ "rev": "acdb1726783637852c01e0ad639ac9cbec28d8c8",
21+ "sha256": "1wszl8q70z6wfgkh2dvgmhhry6qp9nar421qq2ifd17hq2jj9ck3",
22+ "type": "tarball",
23+ "url": "https://github.com/nmattia/niv/archive/acdb1726783637852c01e0ad639ac9cbec28d8c8.tar.gz",
24+ "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
25+ },
26+ "nixpkgs": {
27+ "branch": "nixos-20.09",
28+ "description": "Nix Packages collection",
29+ "homepage": null,
30+ "owner": "nixos",
31+ "repo": "nixpkgs",
32+ "rev": "1c1f5649bb9c1b0d98637c8c365228f57126f361",
33+ "sha256": "0f2nvdijyxfgl5kwyb4465pppd5vkhqxddx6v40k2s0z9jfhj0xl",
34+ "type": "tarball",
35+ "url": "https://github.com/nixos/nixpkgs/archive/1c1f5649bb9c1b0d98637c8c365228f57126f361.tar.gz",
36+ "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
37+ }
3838}
nix/sources.nix+66−20
@@ -6,25 +6,53 @@ let
66 # The fetchers. fetch_<type> fetches specs of type <type>.
77 #
88
9− fetch_file = pkgs: spec:
10− if spec.builtin or true then
11− builtins_fetchurl { inherit (spec) url sha256; }
12− else
13− pkgs.fetchurl { inherit (spec) url sha256; };
9+ fetch_file = pkgs: name: spec:
10+ let
11+ name' = sanitizeName name + "-src";
12+ in
13+ if spec.builtin or true then
14+ builtins_fetchurl { inherit (spec) url sha256; name = name'; }
15+ else
16+ pkgs.fetchurl { inherit (spec) url sha256; name = name'; };
1417
1518 fetch_tarball = pkgs: name: spec:
1619 let
17− ok = str: ! builtins.isNull (builtins.match "[a-zA-Z0-9+-._?=]" str);
18− # sanitize the name, though nix will still fail if name starts with period
19− name' = stringAsChars (x: if ! ok x then "-" else x) "${name}-src";
20+ name' = sanitizeName name + "-src";
2021 in
2122 if spec.builtin or true then
2223 builtins_fetchTarball { name = name'; inherit (spec) url sha256; }
2324 else
2425 pkgs.fetchzip { name = name'; inherit (spec) url sha256; };
2526
26− fetch_git = spec:
27− builtins.fetchGit { url = spec.repo; inherit (spec) rev ref; };
27+ fetch_git = name: spec:
28+ let
29+ ref =
30+ if spec ? ref then spec.ref else
31+ if spec ? branch then "refs/heads/${spec.branch}" else
32+ if spec ? tag then "refs/tags/${spec.tag}" else
33+ abort "In git source '${name}': Please specify `ref`, `tag` or `branch`!";
34+ submodules = if spec ? submodules then spec.submodules else false;
35+ submoduleArg =
36+ let
37+ nixSupportsSubmodules = builtins.compareVersions builtins.nixVersion "2.4" >= 0;
38+ emptyArgWithWarning =
39+ if submodules == true
40+ then
41+ builtins.trace
42+ (
43+ "The niv input \"${name}\" uses submodules "
44+ + "but your nix's (${builtins.nixVersion}) builtins.fetchGit "
45+ + "does not support them"
46+ )
47+ {}
48+ else {};
49+ in
50+ if nixSupportsSubmodules
51+ then { inherit submodules; }
52+ else emptyArgWithWarning;
53+ in
54+ builtins.fetchGit
55+ ({ url = spec.repo; inherit (spec) rev; inherit ref; } // submoduleArg);
2856
2957 fetch_local = spec: spec.path;
3058
@@ -40,11 +68,21 @@ let
4068 # Various helpers
4169 #
4270
71+ # https://github.com/NixOS/nixpkgs/pull/83241/files#diff-c6f540a4f3bfa4b0e8b6bafd4cd54e8bR695
72+ sanitizeName = name:
73+ (
74+ concatMapStrings (s: if builtins.isList s then "-" else s)
75+ (
76+ builtins.split "[^[:alnum:]+._?=-]+"
77+ ((x: builtins.elemAt (builtins.match "\\.*(.*)" x) 0) name)
78+ )
79+ );
80+
4381 # The set of packages used when specs are fetched using non-builtins.
44− mkPkgs = sources:
82+ mkPkgs = sources: system:
4583 let
4684 sourcesNixpkgs =
47− import (builtins_fetchTarball { inherit (sources.nixpkgs) url sha256; }) {};
85+ import (builtins_fetchTarball { inherit (sources.nixpkgs) url sha256; }) { inherit system; };
4886 hasNixpkgsPath = builtins.any (x: x.prefix == "nixpkgs") builtins.nixPath;
4987 hasThisAsNixpkgsPath = <nixpkgs> == ./.;
5088 in
@@ -64,9 +102,9 @@ let
64102
65103 if ! builtins.hasAttr "type" spec then
66104 abort "ERROR: niv spec ${name} does not have a 'type' attribute"
67− else if spec.type == "file" then fetch_file pkgs spec
105+ else if spec.type == "file" then fetch_file pkgs name spec
68106 else if spec.type == "tarball" then fetch_tarball pkgs name spec
69− else if spec.type == "git" then fetch_git spec
107+ else if spec.type == "git" then fetch_git name spec
70108 else if spec.type == "local" then fetch_local spec
71109 else if spec.type == "builtin-tarball" then fetch_builtin-tarball name
72110 else if spec.type == "builtin-url" then fetch_builtin-url name
@@ -80,7 +118,10 @@ let
80118 saneName = stringAsChars (c: if isNull (builtins.match "[a-zA-Z0-9]" c) then "_" else c) name;
81119 ersatz = builtins.getEnv "NIV_OVERRIDE_${saneName}";
82120 in
83− if ersatz == "" then drv else ersatz;
121+ if ersatz == "" then drv else
122+ # this turns the string into an actual Nix path (for both absolute and
123+ # relative paths)
124+ if builtins.substring 0 1 ersatz == "/" then /. + ersatz else /. + builtins.getEnv "PWD" + "/${ersatz}";
84125
85126 # Ports of functions for older nix versions
86127
@@ -98,25 +139,29 @@ let
98139
99140 # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L269
100141 stringAsChars = f: s: concatStrings (map f (stringToCharacters s));
142+ concatMapStrings = f: list: concatStrings (map f list);
101143 concatStrings = builtins.concatStringsSep "";
102144
145+ # https://github.com/NixOS/nixpkgs/blob/8a9f58a375c401b96da862d969f66429def1d118/lib/attrsets.nix#L331
146+ optionalAttrs = cond: as: if cond then as else {};
147+
103148 # fetchTarball version that is compatible between all the versions of Nix
104− builtins_fetchTarball = { url, name, sha256 }@attrs:
149+ builtins_fetchTarball = { url, name ? null, sha256 }@attrs:
105150 let
106151 inherit (builtins) lessThan nixVersion fetchTarball;
107152 in
108153 if lessThan nixVersion "1.12" then
109− fetchTarball { inherit name url; }
154+ fetchTarball ({ inherit url; } // (optionalAttrs (!isNull name) { inherit name; }))
110155 else
111156 fetchTarball attrs;
112157
113158 # fetchurl version that is compatible between all the versions of Nix
114− builtins_fetchurl = { url, sha256 }@attrs:
159+ builtins_fetchurl = { url, name ? null, sha256 }@attrs:
115160 let
116161 inherit (builtins) lessThan nixVersion fetchurl;
117162 in
118163 if lessThan nixVersion "1.12" then
119− fetchurl { inherit url; }
164+ fetchurl ({ inherit url; } // (optionalAttrs (!isNull name) { inherit name; }))
120165 else
121166 fetchurl attrs;
122167
@@ -135,7 +180,8 @@ let
135180 mkConfig =
136181 { sourcesFile ? if builtins.pathExists ./sources.json then ./sources.json else null
137182 , sources ? if isNull sourcesFile then {} else builtins.fromJSON (builtins.readFile sourcesFile)
138− , pkgs ? mkPkgs sources
183+ , system ? builtins.currentSystem
184+ , pkgs ? mkPkgs sources system
139185 }: rec {
140186 # The sources, i.e. the attribute set of spec name to spec
141187 inherit sources;
rel8.cabal+87−58
@@ -1,30 +1,36 @@
11cabal-version: 2.0
22name: rel8
3−version: 0.1.0.0
3+version: 1.4.0.0
44synopsis: Hey! Hey! Can u rel8?
55license: BSD3
66license-file: LICENSE
77author: Oliver Charles
88maintainer: ollie@ocharles.org.uk
9−build-type: Custom
9+homepage: https://github.com/circuithub/rel8
10+bug-reports: https://github.com/circuithub/rel8/issues
11+build-type: Simple
12+extra-doc-files:
13+ README.md
14+ Changelog.md
1015
11−custom-setup
12− setup-depends:
13− base >= 4 && <5,
14− Cabal,
15− cabal-doctest >= 1 && <1.1
16+source-repository head
17+ type: git
18+ location: https://github.com/circuithub/rel8
1619
1720library
1821 build-depends:
1922 aeson
20− , base ^>=4.12 || ^>= 4.13 || ^>= 4.14
23+ , base ^>= 4.14 || ^>=4.15 || ^>=4.16
24+ , bifunctors
2125 , bytestring
2226 , case-insensitive
23− , casing
27+ , comonad
2428 , contravariant
25− , hasql
26− , opaleye ^>= 0.7.1.0
29+ , hasql ^>= 1.4.5.1 || ^>= 1.5.0.0 || ^>= 1.6.0.0
30+ , opaleye ^>= 0.9.6.1
31+ , pretty
2732 , profunctors
33+ , product-profunctors
2834 , scientific
2935 , semialign
3036 , semigroupoids
@@ -35,35 +41,63 @@ library
3541 default-language:
3642 Haskell2010
3743 ghc-options:
44+ -Werror=missing-methods -Werror=incomplete-patterns -Werror=missing-fields
3845 -Weverything -Wno-unsafe -Wno-safe -Wno-missing-safe-haskell-mode
3946 -Wno-missing-import-lists -Wno-prepositive-qualified-module
4047 -Wno-monomorphism-restriction
41− -Wno-missing-local-signatures
48+ -Wno-missing-local-signatures
49+ -Wno-missing-kind-signatures
4250 hs-source-dirs:
4351 src
4452 exposed-modules:
4553 Rel8
54+ Rel8.Expr.Num
55+ Rel8.Expr.Text
56+ Rel8.Expr.Time
57+ Rel8.Tabulate
4658
4759 other-modules:
4860 Rel8.Aggregate
4961
62+ Rel8.Column
63+ Rel8.Column.ADT
64+ Rel8.Column.Either
65+ Rel8.Column.Lift
66+ Rel8.Column.List
67+ Rel8.Column.Maybe
68+ Rel8.Column.NonEmpty
69+ Rel8.Column.Null
70+ Rel8.Column.These
71+
5072 Rel8.Expr
5173 Rel8.Expr.Aggregate
5274 Rel8.Expr.Array
5375 Rel8.Expr.Bool
76+ Rel8.Expr.Default
5477 Rel8.Expr.Eq
5578 Rel8.Expr.Function
5679 Rel8.Expr.Null
57− Rel8.Expr.Num
5880 Rel8.Expr.Opaleye
5981 Rel8.Expr.Ord
6082 Rel8.Expr.Order
83+ Rel8.Expr.Sequence
6184 Rel8.Expr.Serialize
62− Rel8.Expr.Text
63− Rel8.Expr.Time
85+ Rel8.Expr.Window
6486
65− Rel8.Kind.Labels
66− Rel8.Kind.Necessity
87+ Rel8.FCF
88+
89+ Rel8.Kind.Algebra
90+ Rel8.Kind.Context
91+
92+ Rel8.Generic.Construction
93+ Rel8.Generic.Construction.ADT
94+ Rel8.Generic.Construction.Record
95+ Rel8.Generic.Map
96+ Rel8.Generic.Record
97+ Rel8.Generic.Rel8able
98+ Rel8.Generic.Table
99+ Rel8.Generic.Table.ADT
100+ Rel8.Generic.Table.Record
67101
68102 Rel8.Order
69103
@@ -72,84 +106,88 @@ library
72106 Rel8.Query.Distinct
73107 Rel8.Query.Each
74108 Rel8.Query.Either
109+ Rel8.Query.Evaluate
75110 Rel8.Query.Exists
76111 Rel8.Query.Filter
112+ Rel8.Query.Indexed
77113 Rel8.Query.Limit
78114 Rel8.Query.List
79115 Rel8.Query.Maybe
80116 Rel8.Query.Null
81117 Rel8.Query.Opaleye
82− Rel8.Query.Optimize
83118 Rel8.Query.Order
119+ Rel8.Query.Rebind
84120 Rel8.Query.Set
85121 Rel8.Query.SQL
86122 Rel8.Query.These
87123 Rel8.Query.Values
124+ Rel8.Query.Window
88125
89− Rel8.Schema.Column
90− Rel8.Schema.Context
91− Rel8.Schema.Context.Label
92126 Rel8.Schema.Context.Nullify
93− Rel8.Schema.Context.Result
94127 Rel8.Schema.Dict
95128 Rel8.Schema.Field
96− Rel8.Schema.Generic
97− Rel8.Schema.Generic.Test
98129 Rel8.Schema.HTable
99− Rel8.Schema.HTable.Context
100130 Rel8.Schema.HTable.Either
101131 Rel8.Schema.HTable.Identity
102132 Rel8.Schema.HTable.Label
103133 Rel8.Schema.HTable.List
134+ Rel8.Schema.HTable.MapTable
104135 Rel8.Schema.HTable.Maybe
105136 Rel8.Schema.HTable.NonEmpty
106137 Rel8.Schema.HTable.Nullify
107− Rel8.Schema.HTable.Pair
108− Rel8.Schema.HTable.Quartet
109− Rel8.Schema.HTable.Quintet
138+ Rel8.Schema.HTable.Product
110139 Rel8.Schema.HTable.These
111− Rel8.Schema.HTable.Trio
112− Rel8.Schema.HTable.Type
113140 Rel8.Schema.HTable.Vectorize
114− Rel8.Schema.Nullability
141+ Rel8.Schema.Kind
142+ Rel8.Schema.Name
143+ Rel8.Schema.Null
144+ Rel8.Schema.Result
115145 Rel8.Schema.Spec
116− Rel8.Schema.Spec.ConstrainContext
117− Rel8.Schema.Spec.ConstrainDBType
118− Rel8.Schema.Spec.ConstrainType
119146 Rel8.Schema.Table
120147
121148 Rel8.Statement.Delete
122149 Rel8.Statement.Insert
150+ Rel8.Statement.OnConflict
123151 Rel8.Statement.Returning
124152 Rel8.Statement.Select
153+ Rel8.Statement.Set
154+ Rel8.Statement.SQL
125155 Rel8.Statement.Update
156+ Rel8.Statement.Using
126157 Rel8.Statement.View
158+ Rel8.Statement.Where
127159
128160 Rel8.Table
161+ Rel8.Table.ADT
129162 Rel8.Table.Aggregate
130163 Rel8.Table.Alternative
131164 Rel8.Table.Bool
165+ Rel8.Table.Cols
132166 Rel8.Table.Either
133167 Rel8.Table.Eq
134− Rel8.Table.Insert
135− Rel8.Table.Lifted
168+ Rel8.Table.HKD
136169 Rel8.Table.List
137170 Rel8.Table.Maybe
138171 Rel8.Table.Name
139172 Rel8.Table.NonEmpty
173+ Rel8.Table.Null
174+ Rel8.Table.Nullify
140175 Rel8.Table.Opaleye
141176 Rel8.Table.Ord
142177 Rel8.Table.Order
143− Rel8.Table.Recontextualize
178+ Rel8.Table.Projection
179+ Rel8.Table.Rel8able
144180 Rel8.Table.Serialize
145181 Rel8.Table.These
182+ Rel8.Table.Transpose
146183 Rel8.Table.Undefined
147−
148− Rel8.Tabulate
184+ Rel8.Table.Window
149185
150186 Rel8.Type
151− Rel8.Type.Array1D
187+ Rel8.Type.Array
188+ Rel8.Type.Composite
152189 Rel8.Type.Eq
190+ Rel8.Type.Enum
153191 Rel8.Type.Information
154192 Rel8.Type.JSONEncoded
155193 Rel8.Type.JSONBEncoded
@@ -162,8 +200,8 @@ library
162200 Rel8.Type.Sum
163201 Rel8.Type.Tag
164202
165− Rel8.Opaque
166− Rel8.Schema.Structure
203+ Rel8.Window
204+
167205
168206test-suite tests
169207 type: exitcode-stdio-1.0
@@ -173,9 +211,9 @@ test-suite tests
173211 , case-insensitive
174212 , containers
175213 , hasql
176− , hedgehog ^>=1.0.2
177− , lifted-base ^>=0.2.3.12
178− , monad-control ^>=1.0.2.3
214+ , hasql-transaction
215+ , hedgehog ^>= 1.0 || ^>= 1.1
216+ , mmorph
179217 , rel8
180218 , scientific
181219 , tasty
@@ -183,8 +221,12 @@ test-suite tests
183221 , text
184222 , time
185223 , tmp-postgres ^>=1.34.1.0
224+ , transformers
186225 , uuid
187226
227+ other-modules:
228+ Rel8.Generic.Rel8able.Test
229+
188230 main-is: Main.hs
189231 hs-source-dirs: tests
190232 default-language: Haskell2010
@@ -193,16 +235,3 @@ test-suite tests
193235 -Wno-missing-import-lists -Wno-prepositive-qualified-module
194236 -Wno-deprecations -Wno-monomorphism-restriction
195237 -Wno-missing-local-signatures -Wno-implicit-prelude
196−
197−test-suite doctests
198− type: exitcode-stdio-1.0
199− build-depends:
200− base
201− , base-compat
202− , bytestring
203− , doctest
204− , hasql
205− , tmp-postgres
206−
207− main-is: Doctest.hs
208− default-language: Haskell2010
shell.nix+4−4
@@ -1,11 +1,11 @@
11let
22 sources = import ./nix/sources.nix;
3− pkgs = import sources.nixpkgs {};
3+ pkgs = import sources.nixpkgs {overlays = [];};
44 hsPkgs = import ./default.nix;
55in
66 hsPkgs.shellFor {
7− withHoogle = true;
8− tools = { cabal = "3.2.0.0"; haskell-language-server = "latest"; };
7+ withHoogle = false;
8+ tools = { cabal = "latest"; };
99 exactDeps = false;
10− buildInputs = [ pkgs.postgresql ];
10+ buildInputs = [ pkgs.postgresql pkgs.pythonPackages.sphinx ];
1111 }
src/Rel8.hs+438−429
@@ -1,19 +1,7 @@
11{-# language DuplicateRecordFields #-}
22
33module Rel8
4− ( -- * Getting Started
5− -- $setup
6−
7− -- ** Writing Queries
8− -- $guideQueries
9−
10− -- ** Joins
11− -- $guideJoins
12−
13− -- ** Aggregation
14− -- $guideAggregation
15−
16− -- * Database types
4+ ( -- * Database types
175 -- ** @DBType@
186 DBType(..)
197
@@ -25,6 +13,10 @@ module Rel8
2513 -- **** @ReadShow@
2614 , ReadShow(..)
2715
16+ -- **** Generic
17+ , Composite(..), DBComposite(..), compose, decompose
18+ , Enum(..), DBEnum(..), Enumable
19+
2820 -- *** @TypeInformation@
2921 , TypeInformation(..)
3022 , mapTypeInformation
@@ -34,25 +26,44 @@ module Rel8
3426 , DBSemigroup(..)
3527 , DBMonoid(..)
3628 , DBNum
29+ , DBIntegral
3730 , DBFractional
31+ , DBFloating
3832
3933 -- * Tables and higher-kinded tables
40− , Table
34+ , Rel8able, KRel8able
35+ , Column
36+ , HADT
37+ , HEither
38+ , HMaybe
39+ , HList
40+ , HNonEmpty
41+ , HNull
42+ , HThese
43+ , Lift
44+
45+ , Table(..)
46+ , HTable
47+ , Transposes
4148 , AltTable((<|>:))
42− , EqTable, (==:), (/=:)
43− , OrdTable, ascTable, descTable
49+ , AlternativeTable( emptyTable )
50+ , EqTable(..), (==:), (/=:)
51+ , OrdTable(..), (<:), (<=:), (>:), (>=:), ascTable, descTable, greatest, least
4452 , lit
4553 , bool
4654 , case_
55+ , castTable
4756
4857 -- ** @MaybeTable@
49− , MaybeTable(..)
50− , maybeTable, nothingTable, justTable
58+ , MaybeTable
59+ , maybeTable, ($?), nothingTable, justTable
5160 , isNothingTable, isJustTable
61+ , fromMaybeTable
5262 , optional
5363 , catMaybeTable
54− , bindMaybeTable
5564 , traverseMaybeTable
65+ , aggregateMaybeTable
66+ , nameMaybeTable
5667
5768 -- ** @EitherTable@
5869 , EitherTable
@@ -60,8 +71,9 @@ module Rel8
6071 , isLeftTable, isRightTable
6172 , keepLeftTable
6273 , keepRightTable
63− , bindEitherTable
6474 , bitraverseEitherTable
75+ , aggregateEitherTable
76+ , nameEitherTable
6577
6678 -- ** @TheseTable@
6779 , TheseTable
@@ -69,45 +81,110 @@ module Rel8
6981 , isThisTable, isThatTable, isThoseTable
7082 , hasHereTable, hasThereTable
7183 , justHereTable, justThereTable
84+ , alignMaybeTable
7285 , alignBy
7386 , keepHereTable, loseHereTable
7487 , keepThereTable, loseThereTable
7588 , keepThisTable, loseThisTable
7689 , keepThatTable, loseThatTable
7790 , keepThoseTable, loseThoseTable
78− , bindTheseTable
7991 , bitraverseTheseTable
92+ , aggregateTheseTable
93+ , nameTheseTable
8094
8195 -- ** @ListTable@
8296 , ListTable
97+ , listTable, ($*)
98+ , nameListTable
8399 , many
100+ , manyExpr
101+ , catListTable
102+ , catList
84103
85104 -- ** @NonEmptyTable@
86105 , NonEmptyTable
106+ , nonEmptyTable, ($+)
107+ , nameNonEmptyTable
87108 , some
109+ , someExpr
110+ , catNonEmptyTable
111+ , catNonEmpty
112+
113+ -- ** @NullTable@
114+ , NullTable
115+ , nullableTable, nullTable, nullifyTable
116+ , isNullTable, isNonNullTable
117+ , catNullTable
118+ , nameNullTable
119+ , toNullTable, toMaybeTable
120+
121+ -- ** Algebraic data types / sum types
122+ -- $adts
123+
124+ -- *** Naming of ADTs
125+ -- $naming
126+ , NameADT, nameADT
127+ , ADT, ADTable
128+
129+ -- *** Deconstruction of ADTs
130+ -- $deconstruction
131+ , DeconstructADT, deconstructADT
132+
133+ -- *** Construction of ADTs
134+ -- $construction
135+ , BuildADT, buildADT
136+ , ConstructADT, constructADT
137+
138+ -- *** Other ADT operations
139+ , AggregateADT, aggregateADT
140+
141+ -- *** Miscellaneous notes
142+ -- $misc-notes
143+
144+ -- ** @HKD@
145+ , HKD, HKDable
146+ , BuildHKD, buildHKD
147+ , ConstructHKD, constructHKD
148+ , DeconstructHKD, deconstructHKD
149+ , NameHKD, nameHKD
150+ , AggregateHKD, aggregateHKD
88151
89152 -- ** Table schemas
90153 , TableSchema(..)
154+ , Name
155+ , namesFromLabels
156+ , namesFromLabelsWith
91157
92158 -- * Expressions
93159 , Expr
160+ , Sql
94161 , litExpr
162+ , unsafeCastExpr
163+ , unsafeLiteral
95164
96165 -- ** @null@
166+ , NotNull
167+ , Nullable
168+ , Homonullable
169+ , null
97170 , nullify
98171 , nullable
99172 , isNull
100173 , isNonNull
101− , mapNullable
102− , catNullable
174+ , mapNull
175+ , liftOpNull
176+ , catNull
177+ , coalesce
103178
104179 -- ** Boolean operations
180+ , DBEq
105181 , true, false, not_
106182 , (&&.), and_
107183 , (||.), or_
108184 , (==.), (/=.), (==?), (/=?)
109185 , in_
110186 , boolExpr, caseExpr
187+ , like, ilike
111188
112189 -- ** Ordering
113190 , DBOrd
@@ -119,11 +196,19 @@ module Rel8
119196 , Function
120197 , function
121198 , nullaryFunction
199+ , binaryOperator
122200
123201 -- * Queries
124202 , Query
125203 , showQuery
126204
205+ -- ** Projection
206+ , Projection
207+ , Projectable( project )
208+ , Biprojectable( biproject )
209+ , Projecting
210+ , Field
211+
127212 -- ** Selecting rows
128213 , Selects
129214 , each
@@ -132,8 +217,8 @@ module Rel8
132217 -- ** Filtering
133218 , filter
134219 , where_
135− , whereExists
136− , whereNotExists
220+ , present
221+ , absent
137222 , distinct
138223 , distinctOn
139224 , distinctOnBy
@@ -163,13 +248,16 @@ module Rel8
163248
164249 -- ** Aggregation
165250 , Aggregate
251+ , Aggregates
166252 , aggregate
167− , listAgg
168− , nonEmptyAgg
253+ , countRows
169254 , groupBy
255+ , listAgg, listAggExpr
256+ , mode
257+ , nonEmptyAgg, nonEmptyAggExpr
170258 , DBMax, max
171259 , DBMin, min
172− , DBSum, sum
260+ , DBSum, sum, sumWhere, avg
173261 , DBString, stringAgg
174262 , count
175263 , countStar
@@ -186,462 +274,383 @@ module Rel8
186274 , nullsFirst
187275 , nullsLast
188276
277+ -- ** Window functions
278+ , Window
279+ , window
280+ , Partition
281+ , over
282+ , partitionBy
283+ , orderPartitionBy
284+ , cumulative
285+ , cumulative_
286+ , currentRow
287+ , rowNumber
288+ , rank
289+ , denseRank
290+ , percentRank
291+ , cumeDist
292+ , ntile
293+ , lag
294+ , lead
295+ , firstValue
296+ , lastValue
297+ , nthValue
298+ , indexed
299+
300+ -- ** Bindings
301+ , rebind
302+
189303 -- * IO
190304 , Serializable
305+ , ToExprs
306+ , Result
191307
192308 -- * Running statements
309+ -- $running
310+
193311 -- ** @SELECT@
194312 , select
195313
196314 -- ** @INSERT@
197315 , Insert(..)
198316 , OnConflict(..)
317+ , Upsert(..)
199318 , insert
200− , toInsert
201− , toInsertDefaults
319+ , unsafeDefault
320+ , showInsert
202321
203322 -- ** @DELETE@
204323 , Delete(..)
205324 , delete
325+ , showDelete
206326
207327 -- ** @UPDATE@
208− , update
209328 , Update(..)
329+ , update
330+ , showUpdate
210331
211332 -- ** @.. RETURNING@
212333 , Returning(..)
213334
214− -- * TODO
215− -- TODO
216− -- These need organizing, but are reachable from Rel8's documentation so we
217− -- do need to export and document them.
218− , Nullabilizes
219− , HTable
220− , Labelable
221− , Context
335+ -- ** @CREATE VIEW@
336+ , createView
337+ , createOrReplaceView
338+
339+ -- ** Sequences
340+ , nextval
341+ , evaluate
222342 ) where
223343
224344-- base
225345import Prelude ()
226346
227347-- rel8
228−import Rel8.Type
229−import Rel8.Type.Information
230−import Rel8.Type.Ord
231−import Rel8.Type.Semigroup
232−import Rel8.Type.Monoid
233−import Rel8.Type.Num
234−import Rel8.Table
348+import Rel8.Aggregate
349+import Rel8.Column
350+import Rel8.Column.ADT
351+import Rel8.Column.Either
352+import Rel8.Column.Lift
353+import Rel8.Column.List
354+import Rel8.Column.Maybe
355+import Rel8.Column.NonEmpty
356+import Rel8.Column.Null
357+import Rel8.Column.These
235358import Rel8.Expr
359+import Rel8.Expr.Aggregate
236360import Rel8.Expr.Bool
361+import Rel8.Expr.Default
237362import Rel8.Expr.Eq
238363import Rel8.Expr.Function
364+import Rel8.Expr.Null
365+import Rel8.Expr.Opaleye (unsafeCastExpr, unsafeLiteral)
366+import Rel8.Expr.Ord
367+import Rel8.Expr.Order
368+import Rel8.Expr.Serialize
369+import Rel8.Expr.Sequence
370+import Rel8.Expr.Text ( like, ilike )
371+import Rel8.Expr.Window hiding ( cumulative )
372+import Rel8.Generic.Rel8able ( KRel8able, Rel8able )
373+import Rel8.Order
239374import Rel8.Query
240−import Rel8.Query.SQL (showQuery)
375+import Rel8.Query.Aggregate
376+import Rel8.Query.Distinct
241377import Rel8.Query.Each
242−import Rel8.Query.Values
243−import Rel8.Query.Filter
378+import Rel8.Query.Either
379+import Rel8.Query.Evaluate
244380import Rel8.Query.Exists
245−import Rel8.Query.Distinct
381+import Rel8.Query.Filter
382+import Rel8.Query.Indexed
246383import Rel8.Query.Limit
247−import Rel8.Query.Set
248−import Rel8.Table.Maybe
249−import Rel8.Query.Maybe
250−import Rel8.Aggregate
251−import Rel8.Query.Aggregate
252384import Rel8.Query.List
253−import Rel8.Table.NonEmpty
254−import Rel8.Table.List
385+import Rel8.Query.Maybe
386+import Rel8.Query.Null
255387import Rel8.Query.Order
256−import Rel8.Order
257−import Rel8.Table.Serialize
258−import Rel8.Statement.Select
259−import Rel8.Statement.Insert
388+import Rel8.Query.Rebind
389+import Rel8.Query.SQL (showQuery)
390+import Rel8.Query.Set
391+import Rel8.Query.These
392+import Rel8.Query.Values
393+import Rel8.Query.Window
394+import Rel8.Schema.Field
395+import Rel8.Schema.HTable
396+import Rel8.Schema.Name
397+import Rel8.Schema.Null hiding ( nullable )
398+import Rel8.Schema.Result ( Result )
399+import Rel8.Schema.Table
260400import Rel8.Statement.Delete
401+import Rel8.Statement.Insert
402+import Rel8.Statement.OnConflict
261403import Rel8.Statement.Returning
404+import Rel8.Statement.Select
405+import Rel8.Statement.SQL
262406import Rel8.Statement.Update
407+import Rel8.Statement.View
408+import Rel8.Table
409+import Rel8.Table.ADT
263410import Rel8.Table.Aggregate
264−import Rel8.Expr.Aggregate
265−import Rel8.Type.String
266−import Rel8.Type.Sum
267−import Rel8.Expr.Null
268−import Rel8.Query.Null
269−import Rel8.Expr.Order
270−import Rel8.Schema.Nullability
271−import Rel8.Schema.HTable
272−import Rel8.Schema.Context.Label
273−import Rel8.Schema.Table
274−import Rel8.Table.These
275−import Rel8.Query.These
276−import Rel8.Table.Recontextualize
277−import Rel8.Expr.Ord
278411import Rel8.Table.Alternative
279−import Rel8.Table.Either
280412import Rel8.Table.Bool
281−import Rel8.Query.Either
413+import Rel8.Table.Either
282414import Rel8.Table.Eq
415+import Rel8.Table.HKD
416+import Rel8.Table.List
417+import Rel8.Table.Maybe
418+import Rel8.Table.Name
419+import Rel8.Table.NonEmpty
420+import Rel8.Table.Null
421+import Rel8.Table.Opaleye ( castTable )
283422import Rel8.Table.Ord
284423import Rel8.Table.Order
285−import Rel8.Expr.Serialize
286−import Rel8.Table.Insert
287−import Rel8.Type.JSONEncoded
424+import Rel8.Table.Projection
425+import Rel8.Table.Rel8able ()
426+import Rel8.Table.Serialize
427+import Rel8.Table.These
428+import Rel8.Table.Transpose
429+import Rel8.Table.Window
430+import Rel8.Type
431+import Rel8.Type.Composite
432+import Rel8.Type.Eq
433+import Rel8.Type.Enum
434+import Rel8.Type.Information
288435import Rel8.Type.JSONBEncoded
436+import Rel8.Type.JSONEncoded
437+import Rel8.Type.Monoid
438+import Rel8.Type.Num
439+import Rel8.Type.Ord
289440import Rel8.Type.ReadShow
441+import Rel8.Type.Semigroup
442+import Rel8.Type.String
443+import Rel8.Type.Sum
444+import Rel8.Window
290445
291446
292−-- $setup
293−--
294−-- In this section, we'll take a look at using Rel8 to work with a small
295−-- database for Haskell packages. We'll take a look at idiomatic usage of Rel8,
296−-- mapping tables to Haskell, and then look at writing some simple queries.
297−--
298−-- The documentation in this library uses the following language extensions:
299−--
300−-- >>> :set -XBlockArguments
301−-- >>> :set -XDeriveAnyClass
302−-- >>> :set -XDeriveGeneric
303−-- >>> :set -XDerivingStrategies
304−-- >>> :set -XDerivingVia
305−-- >>> :set -XDuplicateRecordFields
306−-- >>> :set -XGeneralizedNewtypeDeriving
307−-- >>> :set -XOverloadedStrings
308−-- >>> :set -XStandaloneDeriving
309−-- >>> :set -XTypeApplications
310−-- >>> :set -XTypeFamilies
311−--
312−-- Before we start writing any Haskell, let's take a look at the schema we'll
313−-- work with.
314−--
315−-- > author: project:
316−-- >
317−-- > Column │ Type │ Nullable Column │ Type │ Nullable
318−-- > ═══════════╪═════════╪══════════ ═══════════╪═════════╪══════════
319−-- > author_id │ integer │ not null author_id │ integer │ not null
320−-- > name │ text │ not null name │ text │ not null
321−-- > url │ text │
322−--
323−-- Our schema consists of two tables - @author@ and @project@. A @project@
324−-- always has an @author@, but not all @author@s have projects. Each @author@
325−-- has a name and (maybe) an associated website, and each project has a name.
326−--
327−-- Now that we've seen our schema, we can begin writing a mapping in Rel8. The
328−-- idiomatic way to map a table is to use a record that is parameterised what
329−-- Rel8 calls an /interpretation functor/, and to define each field with
330−-- 'Column'. For this type to be usable with Rel8 we need it to be an instance
331−-- of 'HigherKindedTable', which can be derived with a combination of
332−-- @DeriveAnyClass@ and @DeriveGeneric@.
333−--
334−-- Following these steps for @author@, we have:
335−--
336−-- > data Author f = Author
337−-- > { authorId :: Column f Int64
338−-- > , name :: Column f Text
339−-- > , url :: Column f (Maybe Text)
340−-- > } deriving (Generic, HigherKindedTable)
341−--
342−-- This is a perfectly reasonable definition, but cautious readers might notice
343−-- a problem - in particular, with the type of the @authorId@ field. While
344−-- @Int64@ is correct, it's not the best type. If we had other identifier types
345−-- in our project, it would be too easy to accidentally mix them up and create
346−-- nonsensical joins. As Haskell programmers, we often solve this problem by
347−-- creating @newtype@ wrappers, and we can also use this technique with Rel8:
348−--
349−-- >>> :{
350−-- newtype AuthorId = AuthorId { toInt64 :: Int64 }
351−-- deriving newtype (DBEq, DBType, Eq, Show)
352−-- :}
353−--
354−-- Now we can write our final schema mapping. First, the @author@ table:
355−--
356−-- >>> :{
357−-- data Author f = Author
358−-- { authorId :: Column f AuthorId
359−-- , authorName :: Column f Text
360−-- , authorUrl :: Column f (Maybe Text)
361−-- }
362−-- deriving stock Generic
363−-- deriving anyclass HigherKindedTable
364−-- :}
365−--
366−-- And similarly, the @project@ table:
367−--
368−-- >>> :{
369−-- data Project f = Project
370−-- { projectAuthorId :: Column f AuthorId
371−-- , projectName :: Column f Text
372−-- }
373−-- deriving stock Generic
374−-- deriving anyclass HigherKindedTable
375−-- :}
376−--
377−-- To show query results in this documentation, we'll also need @Show@
378−-- instances: Unfortunately these definitions look a bit scary, but they are
379−-- essentially just @deriving (Show)@:
380−--
381−-- >>> deriving stock instance f ~ Identity => Show (Author f)
382−-- >>> deriving stock instance f ~ Identity => Show (Project f)
383−--
384−-- These data types describe the structural mapping of the tables, but we also
385−-- need to specify a 'TableSchema' for each table. A @TableSchema@ contains the
386−-- name of the table and the name of all columns in the table, which will
387−-- ultimately allow us to @SELECT@ and @INSERT@ rows for these tables.
388−--
389−-- To define a @TableSchema@, we just need to fill construct appropriate
390−-- @TableSchema@ values. When it comes to the @tableColumns@ field, we
391−-- construct values of our data types above, and set each field to the name of
392−-- the column that it maps to:
393−--
394−-- First, @authorSchema@ describes the column names of the @author@ table when
395−-- associated with the @Author@ type:
396−--
397−-- >>> :{
398−-- authorSchema :: TableSchema (Author ColumnSchema)
399−-- authorSchema = TableSchema
400−-- { tableName = "author"
401−-- , tableSchema = Nothing
402−-- , tableColumns = Author
403−-- { authorId = "author_id"
404−-- , authorName = "name"
405−-- , authorUrl = "url"
406−-- }
407−-- }
408−-- :}
409−--
410−-- And likewise for @project@ and @Project@:
411−--
412−-- >>> :{
413−-- projectSchema :: TableSchema (Project ColumnSchema)
414−-- projectSchema = TableSchema
415−-- { tableName = "project"
416−-- , tableSchema = Nothing
417−-- , tableColumns = Project
418−-- { projectAuthorId = "author_id"
419−-- , projectName = "name"
420−-- }
421−-- }
422−-- :}
423−--
424−-- Aside: you might be wondering why this information isn't in the definitions
425−-- of @Author@ and @Project@ above. Rel8 decouples @TableSchema@ from the data
426−-- types themselves, as not all tables you define will necessarily have a
427−-- schema. For example, Rel8 allows you to define helper types to simplify the
428−-- types of queries - these tables only exist at query time, but there is no
429−-- corresponding base table. We'll see more on this idea later!
430−--
431−-- With these table definitions, we can now start writing some queries! To
432−-- actually run a query, we'll need a database connection. Rel8 uses the
433−-- @hasql@ library, and for this documentation we'll get the connection string
434−-- from the @$TEST_DATABASE_URL@ environment variable.
435−--
436−-- >>> connectionString <- System.Environment.getEnv "TEST_DATABASE_URL"
437−-- >>> Right c <- Hasql.Connection.acquire (Data.ByteString.Char8.pack connectionString)
438−-- >>> Control.Monad.void $ Hasql.Session.run (Hasql.Session.sql "BEGIN") c
439−
440−-- $guideQueries
441−--
442−-- First, we'll take a look at @SELECT@ statements - usually the bulk of most
443−-- database heavy applications.
444−--
445−-- In Rel8, @SELECT@ statements are built using the 'Query' monad. You can
446−-- think of this monad like the ordinary @[]@ (List) monad - but this isn't
447−-- required knowledge.
448−--
449−-- To start, we'll look at one of the simplest queries possible - a basic
450−-- @SELECT * FROM@ statement. To select all rows from a table, we use 'each',
451−-- and supply a 'TableSchema'. So to select all @project@ rows, we can write:
452−--
453−-- >>> :t each projectSchema
454−-- each projectSchema :: Query (Project Expr)
455−--
456−-- Notice that @each@ gives us a @Query@ that yields @Project Expr@ rows. To
457−-- see what this means, let's have a look at a single field of a
458−-- @Project Expr@:
459−--
460−-- >>> let aProjectExpr = undefined :: Project Expr
461−-- >>> :t projectAuthorId aProjectExpr
462−-- projectAuthorId aProjectExpr :: Expr AuthorId
463−--
464−-- Recall we defined @projectAuthorId@ as @Column f AuthorId@. Now we have @f@
465−-- is @Expr@, and @Column Expr AuthorId@ reduces to @Expr AuthorId@. We'll see
466−-- more about @Expr@ soon, but you can think of @Expr a@ as "SQL expressions of
467−-- type @a@".
468−--
469−-- To execute this @Query@, we pass it to 'select':
470−--
471−-- >>> :t select c (each projectSchema)
472−-- select c (each projectSchema) :: MonadIO m => m [Project Identity]
473−--
474−-- When we @select@ things containing @Expr@s, Rel8 builds a new response table
475−-- with the @Identity@ interpretation. This means you'll get back plain Haskell
476−-- values. Studying @projectAuthorId@ again, we have:
477−--
478−-- >>> let aProjectIdentity = undefined :: Project Identity
479−-- >>> :t projectAuthorId aProjectIdentity
480−-- projectAuthorId aProjectIdentity :: AuthorId
481−--
482−-- Here @Column Identity AuthorId@ reduces to just @AuthorId@, with no
483−-- wrappping type at all.
484−--
485−-- Putting this all together, we can run our first query:
486−--
487−-- >>> select c (each projectSchema) >>= mapM_ print
488−-- Project {projectAuthorId = 1, projectName = "rel8"}
489−-- Project {projectAuthorId = 2, projectName = "aeson"}
490−-- Project {projectAuthorId = 2, projectName = "text"}
491−--
492−-- Cool!
493−--
494−-- We now know that 'each' is the equivalent of a @SELECT *@ query, but
495−-- sometimes we're only interested in a subset of the columns of a table. To
496−-- restrict the returned columns, we can specify a projection by using 'Query's
497−-- @Functor@ instance:
498−--
499−-- >>> select c $ projectName <$> each projectSchema
500−-- ["rel8","aeson","text"]
501−
502−-- $guideJoins
503−--
504−-- Another common operation in relational databases is to take the @JOIN@ of
505−-- multiple tables. Rel8 doesn't have a specific join operation, but we can
506−-- recover the functionality of a join by selecting all rows of two tables, and
507−-- then using 'where_' to filter them.
508−--
509−-- To see how this works, first let's look at taking the product of two tables.
510−-- We can do this by simply calling 'each' twice, and then returning a tuple of
511−-- their results.
512−--
513−-- >>> :{
514−-- mapM_ print =<< select c do
515−-- author <- each authorSchema
516−-- project <- each projectSchema
517−-- return (projectName project, authorName author)
518−-- :}
519−-- ("rel8","Ollie")
520−-- ("rel8","Bryan O'Sullivan")
521−-- ("rel8","Emily Pillmore")
522−-- ("aeson","Ollie")
523−-- ("aeson","Bryan O'Sullivan")
524−-- ("aeson","Emily Pillmore")
525−-- ("text","Ollie")
526−-- ("text","Bryan O'Sullivan")
527−-- ("text","Emily Pillmore")
528−--
529−-- This isn't quite right, though, as we have ended up pairing up the wrong
530−-- projects and authors. To fix this, we can use 'where_' to restrict the
531−-- returned rows. We could write:
532−--
533−-- > select c $ do
534−-- > author <- each authorSchema
535−-- > project <- each projectSchema
536−-- > where_ $ projectAuthorId project ==. authorId author
537−-- > return (project, author)
538−--
539−-- but doing this every time you need a join can obscure the meaning of the
540−-- query you're writing. A good practice is to introduce specialised functions
541−-- for the particular joins in your database. In our case, this would be:
542−--
543−-- >>> :{
544−-- projectsForAuthor :: Author Expr -> Query (Project Expr)
545−-- projectsForAuthor a = each projectSchema >>= filter \p ->
546−-- projectAuthorId p ==. authorId a
547−-- :}
548−--
549−-- Our final query is then:
550−--
551−-- >>> :{
552−-- mapM_ print =<< select c do
553−-- author <- each authorSchema
554−-- project <- projectsForAuthor author
555−-- return (projectName project, authorName author)
556−-- :}
557−-- ("rel8","Ollie")
558−-- ("aeson","Bryan O'Sullivan")
559−-- ("text","Bryan O'Sullivan")
560−--
561−-- == @LEFT JOIN@s
562−--
563−-- Rel8 is also capable of performing @LEFT JOIN@s. To perform @LEFT JOIN@s, we
564−-- follow the same approach as before, but use the 'optional' query transformer
565−-- to allow for the possibility of the join to fail.
566−--
567−-- In our test database, we can see that there's another author who we haven't
568−-- seen yet:
569−--
570−-- >>> select c $ authorName <$> each authorSchema
571−-- ["Ollie","Bryan O'Sullivan","Emily Pillmore"]
572−--
573−-- Emily wasn't returned in our earlier query because - in our database - she
574−-- doesn't have any registered projects. We can account for this partiality in
575−-- our original query by wrapping the @projectsForAuthor@ call with 'optional':
576−--
577−-- >>> :{
578−-- mapM_ print =<< select c do
579−-- author <- each authorSchema
580−-- mproject <- optional $ projectsForAuthor author
581−-- return (authorName author, projectName <$> mproject)
582−-- :}
583−-- ("Ollie",Just "rel8")
584−-- ("Bryan O'Sullivan",Just "aeson")
585−-- ("Bryan O'Sullivan",Just "text")
586−-- ("Emily Pillmore",Nothing)
447+-- $running
448+-- To run queries and otherwise interact with a PostgreSQL database, Rel8
449+-- provides 'select', 'insert', 'update' and 'delete' functions. Note that
450+-- 'insert', 'update' and 'delete' will generally need the
451+-- `DuplicateRecordFields` language extension enabled.
587452
588−-- $guideAggregation
453+-- $adts
454+-- Algebraic data types can be modelled between Haskell and SQL.
589455--
590−-- Aggregations are operations like @sum@ and @count@ - operations that reduce
591−-- multiple rows to single values. To perform aggregations in Rel8, we can use
592−-- the 'aggregate' function, which takes a 'Query' of aggregated expressions,
593−-- runs the aggregation, and returns aggregated rows.
456+-- * Your SQL table needs a certain text field that tags which Haskell constructor is in use.
457+-- * You have to use a few combinators to specify the sum type's individual constructors.
458+-- * If you want to do case analysis at the @Expr@ (SQL) level, you can use 'maybe'/'either'-like eliminators.
594459--
595−-- To start, let's look at a simple aggregation that tells us how many projects
596−-- exist:
460+-- The documentation in this section will assume a set of database types like this:
597461--
598−-- >>> error "TODO"
599−--
600−-- Rel8 is also capable of aggregating multiple rows into a single row by
601−-- concatenating all rows as a list. This aggregation allows us to break free
602−-- of the row-orientated nature of SQL and write queries that return tree-like
603−-- structures. Earlier we saw an example of returning authors with their
604−-- projects, but the query didn't do a great job of describing the one-to-many
605−-- relationship between authors and their projects.
606−--
607−-- Let's look again at a query that returns authors and their projects, and
608−-- focus on the /type/ of that query.
609−--
610−-- >>> :{
611−-- projectsForAuthor a = each projectSchema >>= filter \p ->
612−-- projectAuthorId p ==. authorId a
613−-- :}
462+-- @
463+-- data Thing f = ThingEmployer (Employer f) | ThingPotato (Potato f) | Nullary
464+-- deriving stock Generic
614465--
615−-- >>> :{
616−-- let authorsAndProjects = do
617−-- author <- each authorSchema
618−-- project <- projectsForAuthor author
619−-- return (author, project)
620−-- where
621−-- :}
622−--
623−-- >>> :t select c authorsAndProjects
624−-- select c authorsAndProjects
625−-- :: MonadIO m => m [(Author Identity, Project Identity)]
626−--
627−-- Our query gives us a single list of pairs of authors and projects. However,
628−-- with our domain knowledge of the schema, this isn't a great type - what we'd
629−-- rather have is a list of pairs of authors and /lists/ of projects. That is,
630−-- what we'd like is:
631−--
632−-- > [(Author Identity, [Project Identity])]
633−--
634−-- This would be a much better type! Rel8 can produce a query with this type by
635−-- simply wrapping the call to @projectsForAuthor@ with either 'some' or
636−-- 'many'. Here we'll use 'many', which allows for the possibility of an author
637−-- to have no projects:
466+-- data Employer f = Employer { employerId :: f Int32, employerName :: f Text}
467+-- deriving stock Generic
468+-- deriving anyclass Rel8able
638469--
639−-- >>> :{
640−-- mapM_ print =<< select c do
641−-- author <- each authorSchema
642−-- projectNames <- many $ projectName <$> projectsForAuthor author
643−-- return (authorName author, projectNames)
470+-- data Potato f = Potato { size :: f Int32, grower :: f Text }
471+-- deriving stock Generic
472+-- deriving anyclass Rel8able
473+-- @
474+
475+-- $naming
476+--
477+-- First, in your 'TableSchema', name your type like this:
478+--
479+-- @
480+-- thingSchema :: TableSchema (ADT Thing Name)
481+-- thingSchema =
482+-- TableSchema
483+-- { schema = Nothing,
484+-- name = \"thing\",
485+-- columns =
486+-- nameADT @Thing
487+-- \"tag\"
488+-- Employer
489+-- { employerName = \"name\",
490+-- employerId = \"id\"
491+-- }
492+-- Potato {size = \"size\", grower = \"Mary\"}
493+-- }
494+-- @
495+--
496+-- Note that @nameADT \@Thing "tag"@ is variadic: it accepts one
497+-- argument per constructor, except the nullary ones (Nullary) because
498+-- there's nothing to do for them.
499+
500+-- $deconstruction
501+--
502+-- To deconstruct sum types at the SQL level, use 'deconstructADT',
503+-- which is also variadic, and has one argument for each
504+-- constructor. Similar to 'maybe'.
505+--
506+-- @
507+-- query :: Query (ADT Thing Expr)
508+-- query = do
509+-- thingExpr <- each thingSchema
510+-- where_ $
511+-- deconstructADT @Thing
512+-- (\employer -> employerName employer ==. lit \"Mary\")
513+-- (\potato -> grower potato ==. lit \"Mary\")
514+-- (lit False) -- Nullary case
515+-- thingExpr
516+-- pure thingExpr
517+-- @
518+--
519+-- SQL output:
520+--
521+-- @
522+-- SELECT
523+-- CAST("tag0_1" AS text) as "tag",
524+-- CAST("id1_1" AS int4) as "ThingEmployer/_1/employerId",
525+-- CAST("name2_1" AS text) as "ThingEmployer/_1/employerName",
526+-- CAST("size3_1" AS int4) as "ThingPotato/_1/size",
527+-- CAST("Mary4_1" AS text) as "ThingPotato/_1/grower"
528+-- FROM (SELECT
529+-- *
530+-- FROM (SELECT
531+-- "tag" as "tag0_1",
532+-- "id" as "id1_1",
533+-- "name" as "name2_1",
534+-- "size" as "size3_1",
535+-- "Mary" as "Mary4_1"
536+-- FROM "thing" as "T1") as "T1"
537+-- WHERE (CASE WHEN ("tag0_1") = (CAST(E'ThingPotato' AS text)) THEN ("Mary4_1") = (CAST(E'Mary' AS text))
538+-- WHEN ("tag0_1") = (CAST(E'Nullary' AS text)) THEN CAST(FALSE AS bool) ELSE ("name2_1") = (CAST(E'Mary' AS text)) END)) as "T1"
539+-- @
540+
541+-- $construction
542+--
543+-- To construct an ADT, you can use 'buildADT' or 'constructADT'. Consider the following type:
544+--
545+-- @
546+-- data Task f = Pending | Complete (CompletedTask f)
547+-- @
548+--
549+-- 'buildADT' is for constructing values of 'Task' in the 'Expr'
550+-- context. 'buildADT' needs two type-level arguments before its type
551+-- makes any sense. The first argument is the type of the "ADT", which
552+-- in our case is 'Task'. The second is the name of the constructor we
553+-- want to use. So that means we have the following possible
554+-- instantiations of 'buildADT' for 'Task':
555+--
556+-- @
557+-- > :t buildADT @Task @\"Pending\"
558+-- buildADT @Task @\"Pending\" :: ADT Task Expr
559+-- > :t buildADT @Task @\"Complete\"
560+-- buildADT @Task @\"Complete\" :: CompletedTask Expr -> ADT Task Expr
561+-- @
562+--
563+-- Note that as the "Pending" constructor has no fields, @buildADT
564+-- \@Task \@"Pending"@ is equivalent to @lit Pending@. But @buildADT
565+-- \@Task \@"Complete"@ is not the same as @lit . Complete@:
566+--
567+-- @
568+-- > :t lit . Complete
569+-- lit . Complete :: CompletedTask Result -> ADT Task Expr
570+-- @
571+--
572+--
573+-- Note that the former takes a @CompletedTask Expr@ while the latter
574+-- takes a @CompletedTask Result@. The former is more powerful because
575+-- you can construct @Task@s using dynamic values coming a database
576+-- query.
577+--
578+-- To show what this can look like in SQL, consider:
579+--
580+-- @
581+-- > :{
582+-- showQuery $ values
583+-- [ buildADT @Task @\"Pending\"
584+-- , buildADT @Task @\"Complete\" CompletedTask {date = Rel8.Expr.Time.now}
585+-- ]
644586-- :}
645−-- ("Ollie",["rel8"])
646−-- ("Bryan O'Sullivan",["aeson","text"])
647−-- ("Emily Pillmore",[])
587+-- @
588+--
589+-- This produces the following SQL:
590+--
591+-- @
592+-- SELECT
593+-- CAST(\"values0_1\" AS text) as \"tag\",
594+-- CAST(\"values1_1\" AS timestamptz) as \"Complete/_1/date\"
595+-- FROM (SELECT
596+-- *
597+-- FROM (SELECT \"column1\" as \"values0_1\",
598+-- \"column2\" as \"values1_1\"
599+-- FROM
600+-- (VALUES
601+-- (CAST(E'Pending' AS text),CAST(NULL AS timestamptz)),
602+-- (CAST(E'Complete' AS text),CAST(now() AS timestamptz))) as \"V\") as \"T1\") as \"T1\"
603+-- @
604+--
605+-- This is what you get if you run it in @psql@:
606+--
607+--
608+-- @
609+-- tag | Complete/_1/date
610+-- ----------+-------------------------------
611+-- Pending |
612+-- Complete | 2022-05-19 21:28:23.969065+00
613+-- (2 rows)
614+-- @
615+--
616+-- "constructADT" is less convenient but more general alternative to
617+-- "buildADT". It requires only one type-level argument for its type
618+-- to make sense:
619+--
620+-- @
621+-- > :t constructADT @Task
622+-- constructADT @Task
623+-- :: (forall r. r -> (CompletedTask Expr -> r) -> r) -> ADT Task Expr
624+-- @
625+--
626+-- This might still seem a bit opaque, but basically it gives you a
627+-- Church-encoded constructor for arbitrary algebraic data types. You
628+-- might use it as follows:
629+--
630+-- @
631+-- let
632+-- pending :: ADT Task Expr
633+-- pending = constructADT @Task $ \pending _complete -> pending
634+--
635+-- complete :: ADT Task Expr
636+-- complete = constructADT @Task $ \_pending complete -> complete CompletedTask {date = Rel8.Expr.Time.now}
637+-- @
638+--
639+-- These values are otherwise identical to the ones we saw above with
640+-- @buildADT@, it's just a different style of constructing them.
641+--
642+
643+-- $misc-notes
644+--
645+-- 1. Note that the order of the arguments for all of these functions
646+-- is determined by the order of the constructors in the data
647+-- definition. If it were @data Task = Complete (CompletedTask f) |
648+-- Pending@ then the order of all the invocations of @constructADT@
649+-- and @deconstructADT@ would need to change.
650+--
651+-- 2. Maybe this is obvious, but just to spell it out: once you're in
652+-- the @Result@ context, you can of course construct @Task@ values
653+-- normally and use standard Haskell pattern-matching. @constructADT@
654+-- and @deconstructADT@ are specifically only needed in the @Expr@
655+-- context, and they allow you to do the equivalent of pattern
656+-- matching in PostgreSQL.
src/Rel8/Aggregate.hs+59−44
@@ -1,68 +1,83 @@
1−{-# language DerivingVia #-}
2−{-# language GeneralizedNewtypeDeriving #-}
3−{-# language NamedFieldPuns #-}
1+{-# language DataKinds #-}
2+{-# language FlexibleContexts #-}
3+{-# language FlexibleInstances #-}
4+{-# language MultiParamTypeClasses #-}
5+{-# language RankNTypes #-}
46{-# language StandaloneKindSignatures #-}
7+{-# language TypeFamilies #-}
8+{-# language UndecidableInstances #-}
59
610module Rel8.Aggregate
7− ( Aggregate(..), foldInputs, mapInputs
8− , Aggregator(..), unsafeMakeAggregate
11+ ( Aggregate(..), zipOutputs
12+ , unsafeMakeAggregate
13+ , Aggregates
914 )
1015where
1116
1217-- base
13−import Data.Functor.Const ( Const( Const ), getConst )
14−import Data.Kind ( Type )
18+import Control.Applicative ( liftA2 )
19+import Data.Functor.Identity ( Identity( Identity ) )
20+import Data.Kind ( Constraint, Type )
1521import Prelude
1622
23+-- profunctors
24+import Data.Profunctor ( dimap )
25+
1726-- opaleye
18−import qualified Opaleye.Internal.Aggregate as Opaleye
27+import qualified Opaleye.Aggregate as Opaleye
1928import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
20−import qualified Opaleye.Internal.PackMap as Opaleye
29+import qualified Opaleye.Internal.Column as Opaleye
30+
31+-- rel8
32+import Rel8.Expr ( Expr )
33+import Rel8.Schema.HTable.Identity ( HIdentity(..) )
34+import qualified Rel8.Schema.Kind as K
35+import Rel8.Schema.Null ( Sql )
36+import Rel8.Table
37+ ( Table, Columns, Context, fromColumns, toColumns
38+ , FromExprs, fromResult, toResult
39+ , Transpose
40+ )
41+import Rel8.Table.Transpose ( Transposes )
42+import Rel8.Type ( DBType )
2143
22−-- semigroupoids
23−import Data.Functor.Apply ( Apply, WrappedApplicative(..) )
2444
45+-- | 'Aggregate' is a special context used by 'Rel8.aggregate'.
46+type Aggregate :: K.Context
47+newtype Aggregate a = Aggregate (Opaleye.Aggregator () (Expr a))
2548
26−type Aggregate :: Type -> Type
27−newtype Aggregate a = Aggregate (Opaleye.Aggregator () a)
28− deriving newtype Functor
29− deriving Apply via (WrappedApplicative (Opaleye.Aggregator ()))
3049
50+instance Sql DBType a => Table Aggregate (Aggregate a) where
51+ type Columns (Aggregate a) = HIdentity a
52+ type Context (Aggregate a) = Aggregate
53+ type FromExprs (Aggregate a) = a
54+ type Transpose to (Aggregate a) = to a
3155
32−foldInputs :: Monoid b
33− => (Maybe Aggregator -> Opaleye.PrimExpr -> b) -> Aggregate a -> b
34−foldInputs f (Aggregate (Opaleye.Aggregator (Opaleye.PackMap agg))) =
35− getConst $ flip agg () $ \(aggregator, a) ->
36− Const $ f (detuplize <$> aggregator) a
37− where
38− detuplize (operation, ordering, distinction) =
39− Aggregator {operation, ordering, distinction}
56+ toColumns = HIdentity
57+ fromColumns (HIdentity a) = a
58+ toResult = HIdentity . Identity
59+ fromResult (HIdentity (Identity a)) = a
4060
4161
42−mapInputs :: ()
43− => (Opaleye.PrimExpr -> Opaleye.PrimExpr) -> Aggregate a -> Aggregate a
44−mapInputs transform (Aggregate (Opaleye.Aggregator (Opaleye.PackMap agg))) =
45− Aggregate $ Opaleye.Aggregator $ Opaleye.PackMap $ agg . \f input ->
46− f (fmap transform input)
62+-- | @Aggregates a b@ means that the columns in @a@ are all 'Aggregate's
63+-- for the 'Expr' columns in @b@.
64+type Aggregates :: Type -> Type -> Constraint
65+class Transposes Aggregate Expr aggregates exprs => Aggregates aggregates exprs
66+instance Transposes Aggregate Expr aggregates exprs => Aggregates aggregates exprs
4767
4868
49−type Aggregator :: Type
50−data Aggregator = Aggregator
51− { operation :: Opaleye.AggrOp
52− , ordering :: [Opaleye.OrderExpr]
53− , distinction :: Opaleye.AggrDistinct
54− }
69+zipOutputs :: ()
70+ => (Expr a -> Expr b -> Expr c) -> Aggregate a -> Aggregate b -> Aggregate c
71+zipOutputs f (Aggregate a) (Aggregate b) = Aggregate (liftA2 f a b)
5572
5673
57−unsafeMakeAggregate :: ()
58− => (input -> Opaleye.PrimExpr)
59− -> (Opaleye.PrimExpr -> output)
60− -> Maybe Aggregator
61− -> input
74+unsafeMakeAggregate :: forall (input :: Type) (output :: Type) n n' a a'. ()
75+ => (Expr input -> Opaleye.PrimExpr)
76+ -> (Opaleye.PrimExpr -> Expr output)
77+ -> Opaleye.Aggregator (Opaleye.Field_ n a) (Opaleye.Field_ n' a')
78+ -> Expr input
6279 -> Aggregate output
6380unsafeMakeAggregate input output aggregator expr =
64− Aggregate $ Opaleye.Aggregator $ Opaleye.PackMap $ \f _ ->
65− output <$> f (tuplize <$> aggregator, input expr)
66− where
67− tuplize Aggregator {operation, ordering, distinction} =
68− (operation, ordering, distinction)
81+ Aggregate $ dimap in_ out aggregator
82+ where out = output . Opaleye.unColumn
83+ in_ = Opaleye.Column . input . const expr
src/Rel8/Column.hsnew file+31
@@ -0,0 +1,31 @@
1+{-# language DataKinds #-}
2+{-# language StandaloneKindSignatures #-}
3+{-# language TypeFamilies #-}
4+
5+module Rel8.Column
6+ ( Column
7+ , TColumn
8+ )
9+where
10+
11+-- base
12+import Data.Kind ( Type )
13+import Prelude ()
14+
15+-- rel8
16+import Rel8.FCF ( Eval, Exp )
17+import qualified Rel8.Schema.Kind as K
18+import Rel8.Schema.Result ( Result )
19+
20+
21+-- | This type family is used to specify columns in 'Rel8able's. In @Column f
22+-- a@, @f@ is the context of the column (which should be left polymorphic in
23+-- 'Rel8able' definitions), and @a@ is the type of the column.
24+type Column :: K.Context -> Type -> Type
25+type family Column context a where
26+ Column Result a = a
27+ Column context a = context a
28+
29+
30+data TColumn :: K.Context -> Type -> Exp Type
31+type instance Eval (TColumn f a) = Column f a
src/Rel8/Column/ADT.hsnew file+23
@@ -0,0 +1,23 @@
1+{-# language DataKinds #-}
2+{-# language StandaloneKindSignatures #-}
3+{-# language TypeFamilies #-}
4+
5+module Rel8.Column.ADT
6+ ( HADT
7+ )
8+where
9+
10+-- base
11+import Data.Kind ( Type )
12+import Prelude ()
13+
14+-- rel8
15+import qualified Rel8.Schema.Kind as K
16+import Rel8.Schema.Result ( Result )
17+import Rel8.Table.ADT ( ADT )
18+
19+
20+type HADT :: K.Context -> K.Rel8able -> Type
21+type family HADT context t where
22+ HADT Result t = t Result
23+ HADT context t = ADT t context
src/Rel8/Column/Either.hsnew file+26
@@ -0,0 +1,26 @@
1+{-# language DataKinds #-}
2+{-# language StandaloneKindSignatures #-}
3+{-# language TypeFamilyDependencies #-}
4+
5+module Rel8.Column.Either
6+ ( HEither
7+ )
8+where
9+
10+-- base
11+import Data.Kind ( Type )
12+import Prelude
13+
14+-- rel8
15+import qualified Rel8.Schema.Kind as K
16+import Rel8.Schema.Result ( Result )
17+import Rel8.Table.Either ( EitherTable )
18+
19+
20+-- | Nest an 'Either' value within a 'Rel8able'. @HEither f a b@ will produce a
21+-- 'EitherTable' @a b@ in the 'Expr' context, and a 'Either' @a b@ in the
22+-- 'Result' context.
23+type HEither :: K.Context -> Type -> Type -> Type
24+type family HEither context = either | either -> context where
25+ HEither Result = Either
26+ HEither context = EitherTable context
src/Rel8/Column/Lift.hsnew file+23
@@ -0,0 +1,23 @@
1+{-# language DataKinds #-}
2+{-# language StandaloneKindSignatures #-}
3+{-# language TypeFamilies #-}
4+
5+module Rel8.Column.Lift
6+ ( Lift
7+ )
8+where
9+
10+-- base
11+import Data.Kind ( Type )
12+import Prelude ()
13+
14+-- rel8
15+import qualified Rel8.Schema.Kind as K
16+import Rel8.Schema.Result ( Result )
17+import Rel8.Table.HKD ( HKD )
18+
19+
20+type Lift :: K.Context -> Type -> Type
21+type family Lift context a where
22+ Lift Result a = a
23+ Lift context a = HKD a context
src/Rel8/Column/List.hsnew file+25
@@ -0,0 +1,25 @@
1+{-# language DataKinds #-}
2+{-# language StandaloneKindSignatures #-}
3+{-# language TypeFamilyDependencies #-}
4+
5+module Rel8.Column.List
6+ ( HList
7+ )
8+where
9+
10+-- base
11+import Data.Kind ( Type )
12+import Prelude ()
13+
14+-- rel8
15+import qualified Rel8.Schema.Kind as K
16+import Rel8.Schema.Result ( Result )
17+import Rel8.Table.List ( ListTable )
18+
19+
20+-- | Nest a list within a 'Rel8able'. @HList f a@ will produce a 'ListTable'
21+-- @a@ in the 'Expr' context, and a @[a]@ in the 'Result' context.
22+type HList :: K.Context -> Type -> Type
23+type family HList context = list | list -> context where
24+ HList Result = []
25+ HList context = ListTable context
src/Rel8/Column/Maybe.hsnew file+26
@@ -0,0 +1,26 @@
1+{-# language DataKinds #-}
2+{-# language StandaloneKindSignatures #-}
3+{-# language TypeFamilyDependencies #-}
4+
5+module Rel8.Column.Maybe
6+ ( HMaybe
7+ )
8+where
9+
10+-- base
11+import Data.Kind ( Type )
12+import Prelude
13+
14+-- rel8
15+import qualified Rel8.Schema.Kind as K
16+import Rel8.Schema.Result ( Result )
17+import Rel8.Table.Maybe ( MaybeTable )
18+
19+
20+-- | Nest a 'Maybe' value within a 'Rel8able'. @HMaybe f a@ will produce a
21+-- 'MaybeTable' @a@ in the 'Expr' context, and a 'Maybe' @a@ in the 'Result'
22+-- context.
23+type HMaybe :: K.Context -> Type -> Type
24+type family HMaybe context = maybe | maybe -> context where
25+ HMaybe Result = Maybe
26+ HMaybe context = MaybeTable context
src/Rel8/Column/NonEmpty.hsnew file+27
@@ -0,0 +1,27 @@
1+{-# language DataKinds #-}
2+{-# language StandaloneKindSignatures #-}
3+{-# language TypeFamilyDependencies #-}
4+
5+module Rel8.Column.NonEmpty
6+ ( HNonEmpty
7+ )
8+where
9+
10+-- base
11+import Data.Kind ( Type )
12+import Data.List.NonEmpty ( NonEmpty )
13+import Prelude ()
14+
15+-- rel8
16+import qualified Rel8.Schema.Kind as K
17+import Rel8.Schema.Result ( Result )
18+import Rel8.Table.NonEmpty ( NonEmptyTable )
19+
20+
21+-- | Nest a 'NonEmpty' list within a 'Rel8able'. @HNonEmpty f a@ will produce a
22+-- 'NonEmptyTable' @a@ in the 'Expr' context, and a 'NonEmpty' @a@ in the
23+-- 'Result' context.
24+type HNonEmpty :: K.Context -> Type -> Type
25+type family HNonEmpty context = nonEmpty | nonEmpty -> context where
26+ HNonEmpty Result = NonEmpty
27+ HNonEmpty context = NonEmptyTable context
src/Rel8/Column/Null.hsnew file+26
@@ -0,0 +1,26 @@
1+{-# language DataKinds #-}
2+{-# language StandaloneKindSignatures #-}
3+{-# language TypeFamilyDependencies #-}
4+
5+module Rel8.Column.Null
6+ ( HNull
7+ )
8+where
9+
10+-- base
11+import Data.Kind ( Type )
12+import Prelude
13+
14+-- rel8
15+import qualified Rel8.Schema.Kind as K
16+import Rel8.Schema.Result ( Result )
17+import Rel8.Table.Null ( NullTable )
18+
19+
20+-- | Nest a 'Null' value within a 'Rel8able'. @HNull f a@ will produce a
21+-- 'NullTable' @a@ in the 'Expr' context, and a @'Maybe' a@ in the 'Result'
22+-- context.
23+type HNull :: K.Context -> Type -> Type
24+type family HNull context = maybe | maybe -> context where
25+ HNull Result = Maybe
26+ HNull context = NullTable context
src/Rel8/Column/These.hsnew file+29
@@ -0,0 +1,29 @@
1+{-# language DataKinds #-}
2+{-# language StandaloneKindSignatures #-}
3+{-# language TypeFamilyDependencies #-}
4+
5+module Rel8.Column.These
6+ ( HThese
7+ )
8+where
9+
10+-- base
11+import Data.Kind ( Type )
12+import Prelude ()
13+
14+-- rel8
15+import qualified Rel8.Schema.Kind as K
16+import Rel8.Schema.Result ( Result )
17+import Rel8.Table.These ( TheseTable )
18+
19+-- these
20+import Data.These ( These )
21+
22+
23+-- | Nest an 'These' value within a 'Rel8able'. @HThese f a b@ will produce a
24+-- 'TheseTable' @a b@ in the 'Expr' context, and a 'These' @a b@ in the
25+-- 'Result' context.
26+type HThese :: K.Context -> Type -> Type -> Type
27+type family HThese context = these | these -> context where
28+ HThese Result = These
29+ HThese context = TheseTable context
src/Rel8/Expr.hs+65−24
@@ -1,11 +1,12 @@
11{-# language DataKinds #-}
22{-# language DerivingStrategies #-}
33{-# language FlexibleContexts #-}
4−{-# language GADTs #-}
5−{-# language RoleAnnotations #-}
4+{-# language FlexibleInstances #-}
5+{-# language MultiParamTypeClasses #-}
66{-# language ScopedTypeVariables #-}
77{-# language StandaloneKindSignatures #-}
88{-# language TypeApplications #-}
9+{-# language TypeFamilies #-}
910{-# language UndecidableInstances #-}
1011
1112module Rel8.Expr
@@ -14,7 +15,7 @@ module Rel8.Expr
1415where
1516
1617-- base
17−import Data.Kind ( Type )
18+import Data.Functor.Identity ( Identity( Identity ) )
1819import Data.String ( IsString, fromString )
1920import Prelude hiding ( null )
2021
@@ -22,7 +23,8 @@ import Prelude hiding ( null )
2223import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
2324
2425-- rel8
25−import Rel8.Expr.Null ( liftOpNullable, nullify )
26+import Rel8.Expr.Function ( function, nullaryFunction )
27+import Rel8.Expr.Null ( liftOpNull, nullify )
2628import Rel8.Expr.Opaleye
2729 ( castExpr
2830 , fromPrimExpr
@@ -30,41 +32,47 @@ import Rel8.Expr.Opaleye
3032 , zipPrimExprsWith
3133 )
3234import Rel8.Expr.Serialize ( litExpr )
33−import Rel8.Schema.Nullability
34− ( Nullability( Nullable, NonNullable )
35− , Nullabilizes, nullabilization
35+import Rel8.Schema.HTable.Identity ( HIdentity( HIdentity ) )
36+import qualified Rel8.Schema.Kind as K
37+import Rel8.Schema.Null ( Nullity( Null, NotNull ), Sql, nullable )
38+import Rel8.Table
39+ ( Table, Columns, Context, fromColumns, toColumns
40+ , FromExprs, fromResult, toResult
41+ , Transpose
3642 )
3743import Rel8.Type ( DBType )
3844import Rel8.Type.Monoid ( DBMonoid, memptyExpr )
39−import Rel8.Type.Num ( DBFractional, DBNum )
45+import Rel8.Type.Num ( DBFloating, DBFractional, DBNum )
4046import Rel8.Type.Semigroup ( DBSemigroup, (<>.) )
4147
4248
43−type role Expr representational
44−type Expr :: Type -> Type
49+-- | Typed SQL expressions.
50+type Expr :: K.Context
4551newtype Expr a = Expr Opaleye.PrimExpr
4652 deriving stock Show
4753
4854
49−instance (DBSemigroup db, Nullabilizes db a) => Semigroup (Expr a) where
50− (<>) = case nullabilization @a of
51− Nullable -> liftOpNullable (<>.)
52− NonNullable -> (<>.)
55+instance Sql DBSemigroup a => Semigroup (Expr a) where
56+ (<>) = case nullable @a of
57+ Null -> liftOpNull (<>.)
58+ NotNull -> (<>.)
59+ {-# INLINABLE (<>) #-}
5360
5461
55−instance (DBMonoid db, Nullabilizes db a) => Monoid (Expr a) where
56− mempty = case nullabilization @a of
57− Nullable -> nullify memptyExpr
58− NonNullable -> memptyExpr
62+instance Sql DBMonoid a => Monoid (Expr a) where
63+ mempty = case nullable @a of
64+ Null -> nullify memptyExpr
65+ NotNull -> memptyExpr
66+ {-# INLINABLE mempty #-}
5967
6068
61−instance (IsString db, DBType db, Nullabilizes db a) => IsString (Expr a) where
62− fromString = litExpr . case nullabilization @a of
63− Nullable -> Just . fromString
64− NonNullable -> fromString
69+instance (Sql IsString a, Sql DBType a) => IsString (Expr a) where
70+ fromString = litExpr . case nullable @a of
71+ Null -> Just . fromString
72+ NotNull -> fromString
6573
6674
67−instance (DBNum db, Nullabilizes db a) => Num (Expr a) where
75+instance Sql DBNum a => Num (Expr a) where
6876 (+) = zipPrimExprsWith (Opaleye.BinExpr (Opaleye.:+))
6977 (*) = zipPrimExprsWith (Opaleye.BinExpr (Opaleye.:*))
7078 (-) = zipPrimExprsWith (Opaleye.BinExpr (Opaleye.:-))
@@ -77,8 +85,41 @@ instance (DBNum db, Nullabilizes db a) => Num (Expr a) where
7785 fromInteger = castExpr . fromPrimExpr . Opaleye.ConstExpr . Opaleye.IntegerLit
7886
7987
80−instance (DBFractional db, Nullabilizes db a) => Fractional (Expr a) where
88+instance Sql DBFractional a => Fractional (Expr a) where
8189 (/) = zipPrimExprsWith (Opaleye.BinExpr (Opaleye.:/))
8290
8391 fromRational =
8492 castExpr . Expr . Opaleye.ConstExpr . Opaleye.NumericLit . realToFrac
93+
94+
95+instance Sql DBFloating a => Floating (Expr a) where
96+ pi = nullaryFunction "PI"
97+ exp = function "exp"
98+ log = function "ln"
99+ sqrt = function "sqrt"
100+ (**) = zipPrimExprsWith (Opaleye.BinExpr (Opaleye.:^))
101+ logBase = function "log"
102+ sin = function "sin"
103+ cos = function "cos"
104+ tan = function "tan"
105+ asin = function "asin"
106+ acos = function "acos"
107+ atan = function "atan"
108+ sinh = function "sinh"
109+ cosh = function "cosh"
110+ tanh = function "tanh"
111+ asinh = function "asinh"
112+ acosh = function "acosh"
113+ atanh = function "atanh"
114+
115+
116+instance Sql DBType a => Table Expr (Expr a) where
117+ type Columns (Expr a) = HIdentity a
118+ type Context (Expr a) = Expr
119+ type FromExprs (Expr a) = a
120+ type Transpose to (Expr a) = to a
121+
122+ toColumns a = HIdentity a
123+ fromColumns (HIdentity a) = a
124+ toResult a = HIdentity (Identity a)
125+ fromResult (HIdentity (Identity a)) = a
src/Rel8/Expr.hs-boot+5−4
@@ -1,4 +1,4 @@
1−{-# language RoleAnnotations #-}
1+{-# language DataKinds #-}
22{-# language StandaloneKindSignatures #-}
33
44module Rel8.Expr
@@ -7,13 +7,14 @@ module Rel8.Expr
77where
88
99-- base
10−import Data.Kind ( Type )
1110import Prelude ()
1211
1312-- opaleye
1413import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
1514
15+-- rel8
16+import Rel8.Schema.Kind ( Context )
1617
17−type role Expr representational
18−type Expr :: Type -> Type
18+
19+type Expr :: Context
1920newtype Expr a = Expr Opaleye.PrimExpr
src/Rel8/Expr/Aggregate.hs+75−88
@@ -1,6 +1,6 @@
11{-# language DataKinds #-}
2+{-# language FlexibleContexts #-}
23{-# language ScopedTypeVariables #-}
3−{-# language TypeApplications #-}
44{-# language TypeFamilies #-}
55
66{-# options_ghc -fno-warn-redundant-constraints #-}
@@ -10,10 +10,11 @@ module Rel8.Expr.Aggregate
1010 , and, or
1111 , min, max
1212 , sum, sumWhere
13+ , avg
1314 , stringAgg
1415 , groupByExpr
1516 , listAggExpr, nonEmptyAggExpr
16− , sgroupByExpr
17+ , slistAggExpr, snonEmptyAggExpr
1718 )
1819where
1920
@@ -23,10 +24,12 @@ import Data.List.NonEmpty ( NonEmpty )
2324import Prelude hiding ( and, max, min, null, or, sum )
2425
2526-- opaleye
26−import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
27+import qualified Opaleye.Internal.Aggregate as Opaleye
28+import Opaleye.Internal.Column ( Field_( Column ) )
29+import qualified Opaleye.Aggregate as Opaleye
2730
2831-- rel8
29−import Rel8.Aggregate ( Aggregate, Aggregator(..), unsafeMakeAggregate )
32+import Rel8.Aggregate ( Aggregate, unsafeMakeAggregate )
3033import Rel8.Expr ( Expr )
3134import Rel8.Expr.Bool ( caseExpr )
3235import Rel8.Expr.Opaleye
@@ -37,127 +40,111 @@ import Rel8.Expr.Opaleye
3740 )
3841import Rel8.Expr.Null ( null )
3942import Rel8.Expr.Serialize ( litExpr )
40−import Rel8.Schema.Nullability ( Nullability, Nullabilizes, nullabilization )
41−import Rel8.Type.Array ( fromPrimArray )
43+import Rel8.Schema.Null ( Sql, Unnullify )
44+import Rel8.Type ( DBType, typeInformation )
45+import Rel8.Type.Array ( encodeArrayElement )
4246import Rel8.Type.Eq ( DBEq )
47+import Rel8.Type.Information ( TypeInformation )
4348import Rel8.Type.Num ( DBNum )
4449import Rel8.Type.Ord ( DBMax, DBMin )
4550import Rel8.Type.String ( DBString )
4651import Rel8.Type.Sum ( DBSum )
4752
4853
49−count :: Expr a -> Aggregate (Expr Int64)
50−count = unsafeMakeAggregate toPrimExpr fromPrimExpr $
51− Just Aggregator
52− { operation = Opaleye.AggrCount
53− , ordering = []
54− , distinction = Opaleye.AggrAll
55− }
54+-- | Count the occurances of a single column. Corresponds to @COUNT(a)@
55+count :: Expr a -> Aggregate Int64
56+count = unsafeMakeAggregate toPrimExpr fromPrimExpr Opaleye.count
5657
57−
58−countDistinct :: DBEq a => Expr a -> Aggregate (Expr Int64)
58+-- | Count the number of distinct occurances of a single column. Corresponds to
59+-- @COUNT(DISTINCT a)@
60+countDistinct :: Sql DBEq a => Expr a -> Aggregate Int64
5961countDistinct = unsafeMakeAggregate toPrimExpr fromPrimExpr $
60− Just Aggregator
61− { operation = Opaleye.AggrCount
62− , ordering = []
63− , distinction = Opaleye.AggrDistinct
64− }
62+ Opaleye.distinctAggregator Opaleye.count
6563
6664
67−countStar :: Aggregate (Expr Int64)
65+-- | Corresponds to @COUNT(*)@.
66+countStar :: Aggregate Int64
6867countStar = count (litExpr True)
6968
7069
71−countWhere :: Expr Bool -> Aggregate (Expr Int64)
70+-- | A count of the number of times a given expression is @true@.
71+countWhere :: Expr Bool -> Aggregate Int64
7272countWhere condition = count (caseExpr [(condition, litExpr (Just True))] null)
7373
7474
75−and :: Expr Bool -> Aggregate (Expr Bool)
76−and = unsafeMakeAggregate toPrimExpr fromPrimExpr $
77− Just Aggregator
78− { operation = Opaleye.AggrBoolAnd
79− , ordering = []
80− , distinction = Opaleye.AggrAll
81− }
75+-- | Corresponds to @bool_and@.
76+and :: Expr Bool -> Aggregate Bool
77+and = unsafeMakeAggregate toPrimExpr fromPrimExpr Opaleye.boolAnd
8278
8379
84−or :: Expr Bool -> Aggregate (Expr Bool)
85−or = unsafeMakeAggregate toPrimExpr fromPrimExpr $
86− Just Aggregator
87− { operation = Opaleye.AggrBoolOr
88− , ordering = []
89− , distinction = Opaleye.AggrAll
90− }
80+-- | Corresponds to @bool_or@.
81+or :: Expr Bool -> Aggregate Bool
82+or = unsafeMakeAggregate toPrimExpr fromPrimExpr Opaleye.boolOr
9183
9284
93−max :: (DBMax db, Nullabilizes db a) => Expr a -> Aggregate (Expr a)
94−max = unsafeMakeAggregate toPrimExpr fromPrimExpr $
95− Just Aggregator
96− { operation = Opaleye.AggrSum
97− , ordering = []
98− , distinction = Opaleye.AggrAll
99− }
85+-- | Produce an aggregation for @Expr a@ using the @max@ function.
86+max :: Sql DBMax a => Expr a -> Aggregate a
87+max = unsafeMakeAggregate toPrimExpr fromPrimExpr Opaleye.unsafeMax
10088
10189
102−min :: (DBMin db, Nullabilizes db a) => Expr a -> Aggregate (Expr a)
103−min = unsafeMakeAggregate toPrimExpr fromPrimExpr $
104− Just Aggregator
105− { operation = Opaleye.AggrSum
106− , ordering = []
107− , distinction = Opaleye.AggrAll
108− }
90+-- | Produce an aggregation for @Expr a@ using the @max@ function.
91+min :: Sql DBMin a => Expr a -> Aggregate a
92+min = unsafeMakeAggregate toPrimExpr fromPrimExpr Opaleye.unsafeMin
10993
94+-- | Corresponds to @sum@. Note that in SQL, @sum@ is type changing - for
95+-- example the @sum@ of @integer@ returns a @bigint@. Rel8 doesn't support
96+-- this, and will add explicit casts back to the original input type. This can
97+-- lead to overflows, and if you anticipate very large sums, you should upcast
98+-- your input.
99+sum :: Sql DBSum a => Expr a -> Aggregate a
100+sum = unsafeMakeAggregate toPrimExpr (castExpr . fromPrimExpr) Opaleye.unsafeSum
110101
111−sum :: (DBSum db, Nullabilizes db a) => Expr a -> Aggregate (Expr a)
112−sum = unsafeMakeAggregate toPrimExpr (castExpr . fromPrimExpr) $
113− Just Aggregator
114− { operation = Opaleye.AggrSum
115− , ordering = []
116− , distinction = Opaleye.AggrAll
117− }
118102
103+-- | Corresponds to @avg@. Note that in SQL, @avg@ is type changing - for
104+-- example, the @avg@ of @integer@ returns a @numeric@. Rel8 doesn't support
105+-- this, and will add explicit casts back to the original input type. If you
106+-- need a fractional result on an integral column, you should cast your input
107+-- to 'Double' or 'Data.Scientific.Scientific' before calling 'avg'.
108+avg :: Sql DBSum a => Expr a -> Aggregate a
109+avg = unsafeMakeAggregate toPrimExpr (castExpr . fromPrimExpr) Opaleye.unsafeAvg
119110
120−sumWhere :: (DBNum db, DBSum db, Nullabilizes db a)
121− => Expr Bool -> Expr a -> Aggregate (Expr a)
111+-- | Take the sum of all expressions that satisfy a predicate.
112+sumWhere :: (Sql DBNum a, Sql DBSum a)
113+ => Expr Bool -> Expr a -> Aggregate a
122114sumWhere condition a = sum (caseExpr [(condition, a)] 0)
123115
124116
125−stringAgg :: (DBString db, Nullabilizes db a)
126− => Expr db -> Expr a -> Aggregate (Expr a)
117+-- | Corresponds to @string_agg()@.
118+stringAgg :: Sql DBString a
119+ => Expr db -> Expr a -> Aggregate a
127120stringAgg delimiter =
128− unsafeMakeAggregate toPrimExpr (castExpr . fromPrimExpr) $
129− Just Aggregator
130− { operation = Opaleye.AggrStringAggr (toPrimExpr delimiter)
131− , ordering = []
132− , distinction = Opaleye.AggrAll
133− }
121+ unsafeMakeAggregate toPrimExpr (castExpr . fromPrimExpr) (Opaleye.stringAgg (Column (toPrimExpr delimiter)))
134122
135123
136−groupByExpr :: (DBEq db, Nullabilizes db a) => Expr a -> Aggregate (Expr a)
137−groupByExpr = sgroupByExpr nullabilization
124+-- | Aggregate a value by grouping by it.
125+groupByExpr :: Sql DBEq a => Expr a -> Aggregate a
126+groupByExpr = unsafeMakeAggregate toPrimExpr fromPrimExpr Opaleye.groupBy
138127
139128
140−listAggExpr :: Expr a -> Aggregate (Expr [a])
141−listAggExpr = unsafeMakeAggregate toPrimExpr from $ Just
142− Aggregator
143− { operation = Opaleye.AggrArr
144− , ordering = []
145− , distinction = Opaleye.AggrAll
146− }
147− where
148− from = fromPrimExpr . fromPrimArray
129+-- | Collect expressions values as a list.
130+listAggExpr :: Sql DBType a => Expr a -> Aggregate [a]
131+listAggExpr = slistAggExpr typeInformation
132+
149133
134+-- | Collect expressions values as a non-empty list.
135+nonEmptyAggExpr :: Sql DBType a => Expr a -> Aggregate (NonEmpty a)
136+nonEmptyAggExpr = snonEmptyAggExpr typeInformation
150137
151−nonEmptyAggExpr :: Expr a -> Aggregate (Expr (NonEmpty a))
152−nonEmptyAggExpr = unsafeMakeAggregate toPrimExpr from $ Just
153− Aggregator
154− { operation = Opaleye.AggrArr
155− , ordering = []
156− , distinction = Opaleye.AggrAll
157− }
138+
139+slistAggExpr :: ()
140+ => TypeInformation (Unnullify a) -> Expr a -> Aggregate [a]
141+slistAggExpr info = unsafeMakeAggregate to fromPrimExpr Opaleye.arrayAgg
158142 where
159− from = fromPrimExpr . fromPrimArray
143+ to = encodeArrayElement info . toPrimExpr
160144
161145
162−sgroupByExpr :: DBEq db => Nullability db a -> Expr a -> Aggregate (Expr a)
163−sgroupByExpr _ = unsafeMakeAggregate toPrimExpr fromPrimExpr Nothing
146+snonEmptyAggExpr :: ()
147+ => TypeInformation (Unnullify a) -> Expr a -> Aggregate (NonEmpty a)
148+snonEmptyAggExpr info = unsafeMakeAggregate to fromPrimExpr Opaleye.arrayAgg
149+ where
150+ to = encodeArrayElement info . toPrimExpr
src/Rel8/Expr/Array.hs+19−14
@@ -1,13 +1,12 @@
11{-# language DataKinds #-}
22{-# language FlexibleContexts #-}
3−{-# language ScopedTypeVariables #-}
4−{-# language TypeApplications #-}
53{-# language TypeFamilies #-}
64
75{-# options_ghc -fno-warn-redundant-constraints #-}
86
97module Rel8.Expr.Array
108 ( listOf, nonEmptyOf
9+ , slistOf, snonEmptyOf
1110 , sappend, sappend1, sempty
1211 )
1312where
@@ -26,28 +25,34 @@ import Rel8.Expr.Opaleye
2625 , zipPrimExprsWith
2726 )
2827import Rel8.Type ( DBType, typeInformation )
29−import Rel8.Type.Array ( array, zipPrimArraysWith )
28+import Rel8.Type.Array ( array )
3029import Rel8.Type.Information ( TypeInformation(..) )
31−import Rel8.Schema.Nullability ( Nullability, Nullabilizes )
30+import Rel8.Schema.Null ( Unnullify, Sql )
3231
3332
3433sappend :: Expr [a] -> Expr [a] -> Expr [a]
35−sappend = zipPrimExprsWith (zipPrimArraysWith (Opaleye.BinExpr (Opaleye.:||)))
34+sappend = zipPrimExprsWith (Opaleye.BinExpr (Opaleye.:||))
3635
3736
3837sappend1 :: Expr (NonEmpty a) -> Expr (NonEmpty a) -> Expr (NonEmpty a)
39−sappend1 = zipPrimExprsWith (zipPrimArraysWith (Opaleye.BinExpr (Opaleye.:||)))
38+sappend1 = zipPrimExprsWith (Opaleye.BinExpr (Opaleye.:||))
4039
4140
42−sempty :: Nullability t a -> TypeInformation t -> Expr [a]
43−sempty _ info = fromPrimExpr $ array info []
41+sempty :: TypeInformation (Unnullify a) -> Expr [a]
42+sempty info = fromPrimExpr $ array info []
4443
4544
46−listOf :: forall a t. (Nullabilizes t a, DBType t)
47− => [Expr a] -> Expr [a]
48−listOf = fromPrimExpr . array (typeInformation @t) . fmap toPrimExpr
45+slistOf :: TypeInformation (Unnullify a) -> [Expr a] -> Expr [a]
46+slistOf info = fromPrimExpr . array info . fmap toPrimExpr
4947
5048
51−nonEmptyOf :: forall a t. (Nullabilizes t a, DBType t)
52− => NonEmpty (Expr a) -> Expr (NonEmpty a)
53−nonEmptyOf = fromPrimExpr . array (typeInformation @t) . fmap toPrimExpr
49+snonEmptyOf :: TypeInformation (Unnullify a) -> NonEmpty (Expr a) -> Expr (NonEmpty a)
50+snonEmptyOf info = fromPrimExpr . array info . fmap toPrimExpr
51+
52+
53+listOf :: Sql DBType a => [Expr a] -> Expr [a]
54+listOf = slistOf typeInformation
55+
56+
57+nonEmptyOf :: Sql DBType a => NonEmpty (Expr a) -> Expr (NonEmpty a)
58+nonEmptyOf = snonEmptyOf typeInformation
src/Rel8/Expr/Bool.hs+8−42
@@ -1,3 +1,5 @@
1+{-# language GADTs #-}
2+
13module Rel8.Expr.Bool
24 ( false, true
35 , (&&.), (||.), not_
@@ -17,7 +19,7 @@ import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
1719
1820-- rel8
1921import {-# SOURCE #-} Rel8.Expr ( Expr( Expr ) )
20−import Rel8.Expr.Opaleye ( mapPrimExpr, zipPrimExprsWith )
22+import Rel8.Expr.Opaleye ( mapPrimExpr, toPrimExpr, zipPrimExprsWith )
2123import Rel8.Expr.Serialize ( litExpr )
2224
2325
@@ -32,68 +34,28 @@ true = litExpr True
3234
3335
3436-- | The SQL @AND@ operator.
35−--
36−-- >>> :{
37−-- mapM_ print =<< select c do
38−-- x <- values [lit True, lit False]
39−-- y <- values [lit True, lit False]
40−-- return (x, y, x &&. y)
41−-- :}
42−-- (True,True,True)
43−-- (True,False,False)
44−-- (False,True,False)
45−-- (False,False,False)
4637(&&.) :: Expr Bool -> Expr Bool -> Expr Bool
4738(&&.) = zipPrimExprsWith (Opaleye.BinExpr Opaleye.OpAnd)
4839infixr 3 &&.
4940
5041
5142-- | The SQL @OR@ operator.
52−--
53−-- >>> :{
54−-- mapM_ print =<< select c do
55−-- x <- values [lit True, lit False]
56−-- y <- values [lit True, lit False]
57−-- return (x, y, x ||. y)
58−-- :}
59−-- (True,True,True)
60−-- (True,False,True)
61−-- (False,True,True)
62−-- (False,False,False)
6343(||.) :: Expr Bool -> Expr Bool -> Expr Bool
6444(||.) = zipPrimExprsWith (Opaleye.BinExpr Opaleye.OpOr)
6545infixr 2 ||.
6646
6747
6848-- | The SQL @NOT@ operator.
69−--
70−-- >>> select c $ pure $ not_ $ lit True
71−-- [False]
72−--
73−-- >>> select c $ pure $ not_ $ lit False
74−-- [True]
7549not_ :: Expr Bool -> Expr Bool
7650not_ = mapPrimExpr (Opaleye.UnExpr Opaleye.OpNot)
7751
7852
7953-- | Fold @AND@ over a collection of expressions.
80−--
81−-- >>> select c $ pure $ and_ [ lit True ==. lit False, lit False, lit True ]
82−-- [False]
83−--
84−-- >>> select c $ pure $ and_ []
85−-- [True]
8654and_ :: Foldable f => f (Expr Bool) -> Expr Bool
8755and_ = foldl' (&&.) true
8856
8957
9058-- | Fold @OR@ over a collection of expressions.
91−--
92−-- >>> select c $ pure $ or_ [ lit True ==. lit False, lit False, lit True ]
93−-- [True]
94−--
95−-- >>> select c $ pure $ or_ []
96−-- [False]
9759or_ :: Foldable f => f (Expr Bool) -> Expr Bool
9860or_ = foldl' (||.) false
9961
@@ -115,9 +77,13 @@ caseExpr :: [(Expr Bool, Expr a)] -> Expr a -> Expr a
11577caseExpr branches (Expr fallback) =
11678 Expr $ Opaleye.CaseExpr (map go branches) fallback
11779 where
118− go (Expr condition, Expr value) = (condition, value)
80+ go (condition, value) = (toPrimExpr condition, toPrimExpr value)
11981
12082
83+-- | Convert a @Expr (Maybe Bool)@ to a @Expr Bool@ by treating @Nothing@ as
84+-- @False@. This can be useful when combined with 'Rel8.where_', which expects
85+-- a @Bool@, and produces expressions that optimize better than general case
86+-- analysis.
12187coalesce :: Expr (Maybe Bool) -> Expr Bool
12288coalesce (Expr a) = Expr a &&. Expr (Opaleye.FunExpr "COALESCE" [a, untrue])
12389 where
src/Rel8/Expr/Default.hsnew file+35
@@ -0,0 +1,35 @@
1+module Rel8.Expr.Default
2+ ( unsafeDefault
3+ )
4+where
5+
6+-- base
7+import Prelude ()
8+
9+-- opaleye
10+import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
11+
12+-- rel8
13+import Rel8.Expr ( Expr )
14+import Rel8.Expr.Opaleye ( fromPrimExpr )
15+
16+
17+-- | Corresponds to the SQL @DEFAULT@ expression.
18+--
19+-- This 'Expr' is unsafe for numerous reasons, and should be used with care:
20+--
21+-- 1. This 'Expr' only makes sense in an @INSERT@ or @UPDATE@ statement.
22+--
23+-- 2. Rel8 is not able to verify that a particular column actually has a
24+-- @DEFAULT@ value. Trying to use @unsafeDefault@ where there is no default
25+-- will cause a runtime crash
26+--
27+-- 3. @DEFAULT@ values can not be transformed. For example, the innocuous Rel8
28+-- code @unsafeDefault + 1@ will crash, despite type checking.
29+--
30+-- Given all these caveats, we suggest avoiding the use of default values where
31+-- possible, instead being explicit. A common scenario where default values are
32+-- used is with auto-incrementing identifier columns. In this case, we suggest
33+-- using 'Rel8.nextval' instead.
34+unsafeDefault :: Expr a
35+unsafeDefault = fromPrimExpr Opaleye.DefaultInsertExpr
src/Rel8/Expr/Eq.hs+52−49
@@ -1,12 +1,13 @@
1+{-# language FlexibleContexts #-}
12{-# language GADTs #-}
2−{-# language LambdaCase #-}
3+{-# language ScopedTypeVariables #-}
4+{-# language TypeApplications #-}
35{-# language ViewPatterns #-}
46
57{-# options_ghc -fno-warn-redundant-constraints #-}
68
79module Rel8.Expr.Eq
8− ( seq, sne
9− , (==.), (/=.)
10+ ( (==.), (/=.)
1011 , (==?), (/=?)
1112 , in_
1213 )
@@ -15,7 +16,7 @@ where
1516-- base
1617import Data.Foldable ( toList )
1718import Data.List.NonEmpty ( nonEmpty )
18−import Prelude hiding ( seq, sin )
19+import Prelude
1920
2021-- opaleye
2122import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
@@ -23,12 +24,9 @@ import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
2324-- rel8
2425import Rel8.Expr ( Expr )
2526import Rel8.Expr.Bool ( (&&.), (||.), false, or_, coalesce )
26−import Rel8.Expr.Null ( isNull, unsafeLiftOpNullable )
27+import Rel8.Expr.Null ( isNull, unsafeLiftOpNull )
2728import Rel8.Expr.Opaleye ( fromPrimExpr, toPrimExpr, zipPrimExprsWith )
28−import Rel8.Schema.Nullability
29− ( Nullability( NonNullable, Nullable )
30− , Nullabilizes, nullabilization
31− )
29+import Rel8.Schema.Null ( Nullity( NotNull, Null ), Sql, nullable )
3230import Rel8.Type.Eq ( DBEq )
3331
3432
@@ -40,59 +38,64 @@ ne :: DBEq a => Expr a -> Expr a -> Expr Bool
4038ne = zipPrimExprsWith (Opaleye.BinExpr (Opaleye.:<>))
4139
4240
43−seq :: DBEq db => Nullability db a -> Expr a -> Expr a -> Expr Bool
44−seq = \case
45− Nullable -> \ma mb -> isNull ma &&. isNull mb ||. ma ==? mb
46− NonNullable -> eq
47−
48−
49−sne :: DBEq db => Nullability db a -> Expr a -> Expr a -> Expr Bool
50−sne = \case
51− Nullable -> \ma mb -> isNull ma `ne` isNull mb ||. ma /=? mb
52− NonNullable -> ne
53−
54−
55−sin :: (DBEq db, Foldable f)
56− => Nullability db a -> f (Expr a) -> Expr a -> Expr Bool
57−sin nullability (toList -> as) a = case nullability of
58− Nullable -> or_ $ map (seq Nullable a) as
59− NonNullable -> case nonEmpty as of
60− Nothing -> false
61− Just xs ->
62− fromPrimExpr $
63− Opaleye.BinExpr Opaleye.OpIn
64− (toPrimExpr a)
65− (Opaleye.ListExpr (toPrimExpr <$> xs))
66−
67−
68−(==.) :: (DBEq db, Nullabilizes db a) => Expr a -> Expr a -> Expr Bool
69−(==.) = seq nullabilization
41+-- | Compare two expressions for equality.
42+--
43+-- This corresponds to the SQL @IS NOT DISTINCT FROM@ operator, and will equate
44+-- @null@ values as @true@. This differs from @=@ which would return @null@.
45+-- This operator matches Haskell's '==' operator. For an operator identical to
46+-- SQL @=@, see '==?'.
47+(==.) :: forall a. Sql DBEq a => Expr a -> Expr a -> Expr Bool
48+(==.) = case nullable @a of
49+ Null -> \ma mb -> isNull ma &&. isNull mb ||. ma ==? mb
50+ NotNull -> eq
7051infix 4 ==.
52+{-# INLINABLE (==.) #-}
7153
7254
73−(/=.) :: (DBEq db, Nullabilizes db a) => Expr a -> Expr a -> Expr Bool
74−(/=.) = sne nullabilization
55+-- | Test if two expressions are different (not equal).
56+--
57+-- This corresponds to the SQL @IS DISTINCT FROM@ operator, and will return
58+-- @false@ when comparing two @null@ values. This differs from ordinary @=@
59+-- which would return @null@. This operator is closer to Haskell's '=='
60+-- operator. For an operator identical to SQL @=@, see '/=?'.
61+(/=.) :: forall a. Sql DBEq a => Expr a -> Expr a -> Expr Bool
62+(/=.) = case nullable @a of
63+ Null -> \ma mb -> isNull ma `ne` isNull mb ||. ma /=? mb
64+ NotNull -> ne
7565infix 4 /=.
66+{-# INLINABLE (/=.) #-}
7667
7768
69+-- | Test if two expressions are equal. This operator is usually the best
70+-- choice when forming join conditions, as PostgreSQL has a much harder time
71+-- optimizing a join that has multiple 'True' conditions.
72+--
73+-- This corresponds to the SQL @=@ operator, though it will always return a
74+-- 'Bool'.
7875(==?) :: DBEq a => Expr (Maybe a) -> Expr (Maybe a) -> Expr Bool
79−a ==? b = coalesce $ unsafeLiftOpNullable eq a b
76+a ==? b = coalesce $ unsafeLiftOpNull eq a b
8077infix 4 ==?
8178
8279
80+-- | Test if two expressions are different.
81+--
82+-- This corresponds to the SQL @<>@ operator, though it will always return a
83+-- 'Bool'.
8384(/=?) :: DBEq a => Expr (Maybe a) -> Expr (Maybe a) -> Expr Bool
84−a /=? b = coalesce $ unsafeLiftOpNullable ne a b
85+a /=? b = coalesce $ unsafeLiftOpNull ne a b
8586infix 4 /=?
8687
8788
8889-- | Like the SQL @IN@ operator, but implemented by folding over a list with
8990-- '==.' and '||.'.
90−--
91−-- >>> select c $ return $ lit (5 :: Int32) `in_` [ lit x | x <- [1..5] ]
92−-- [True]
93−--
94−-- >>> select c $ return $ lit (42 :: Int32) `in_` [ lit x | x <- [1..5] ]
95−-- [False]
96−in_ :: (DBEq db, Nullabilizes db a, Foldable f)
97− => f (Expr a) -> Expr a -> Expr Bool
98−in_ = sin nullabilization
91+in_ :: forall a f. (Sql DBEq a, Foldable f)
92+ => Expr a -> f (Expr a) -> Expr Bool
93+in_ a (toList -> as) = case nullable @a of
94+ Null -> or_ $ map (a ==.) as
95+ NotNull -> case nonEmpty as of
96+ Nothing -> false
97+ Just xs ->
98+ fromPrimExpr $
99+ Opaleye.BinExpr Opaleye.OpIn
100+ (toPrimExpr a)
101+ (Opaleye.ListExpr (toPrimExpr <$> xs))
src/Rel8/Expr/Function.hs+8−38
@@ -20,22 +20,24 @@ import Prelude
2020import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
2121
2222-- rel8
23−import Rel8.Expr ( Expr( Expr ) )
23+import {-# SOURCE #-} Rel8.Expr ( Expr( Expr ) )
2424import Rel8.Expr.Opaleye
2525 ( castExpr
2626 , fromPrimExpr, toPrimExpr, zipPrimExprsWith
2727 )
28−import Rel8.Schema.Nullability ( Nullabilizes )
28+import Rel8.Schema.Null ( Sql )
2929import Rel8.Type ( DBType )
3030
3131
32+-- | This type class exists to allow 'function' to have arbitrary arity. It's
33+-- mostly an implementation detail, and typical uses of 'Function' shouldn't
34+-- need this to be specified.
3235type Function :: Type -> Type -> Constraint
3336class Function arg res where
3437 applyArgument :: ([Opaleye.PrimExpr] -> Opaleye.PrimExpr) -> arg -> res
3538
3639
37−instance (arg ~ Expr a, DBType db, Nullabilizes db b) => Function arg (Expr b)
38− where
40+instance (arg ~ Expr a, Sql DBType b) => Function arg (Expr b) where
3941 applyArgument f a = castExpr $ fromPrimExpr $ f [toPrimExpr a]
4042
4143
@@ -45,49 +47,17 @@ instance (arg ~ Expr a, Function args res) => Function arg (args -> res) where
4547
4648-- | Construct an n-ary function that produces an 'Expr' that when called runs
4749-- a SQL function.
48−--
49−-- For example, here's how we can wrap PostgreSQL's @factorial@ function:
50−--
51−-- >>> :{
52−-- factorial :: Expr Int64 -> Expr Data.Scientific.Scientific
53−-- factorial = function "factorial"
54−-- :}
55−--
56−-- >>> select c $ pure $ factorial 5
57−-- [120.0]
58−--
59−-- The same approach works for any number of arguments:
60−--
61−-- >>> :{
62−-- power :: Expr Float -> Expr Float -> Expr Double
63−-- power = function "power"
64−-- :}
65−--
66−-- >>> select c $ pure $ power 9 3
67−-- [729.0]
6850function :: Function args result => String -> args -> result
6951function = applyArgument . Opaleye.FunExpr
7052
7153
7254-- | Construct a function call for functions with no arguments.
73−--
74−-- For example, we can call the database function @pi()@ by using
75−-- @nullaryFunction@:
76−--
77−-- >>> :{
78−-- sqlPi :: Expr Double
79−-- sqlPi = nullaryFunction "pi"
80−-- :}
81−--
82−-- >>> select c $ pure $ sqlPi
83−-- [3.141592653589793]
84−nullaryFunction :: (DBType db, Nullabilizes db a) => String -> Expr a
55+nullaryFunction :: Sql DBType a => String -> Expr a
8556nullaryFunction name = castExpr $ Expr (Opaleye.FunExpr name [])
8657
8758
8859-- | Construct an expression by applying an infix binary operator to two
8960-- operands.
90−binaryOperator :: (DBType db, Nullabilizes db c)
91− => String -> Expr a -> Expr b -> Expr c
61+binaryOperator :: Sql DBType c => String -> Expr a -> Expr b -> Expr c
9262binaryOperator operator a b =
9363 castExpr $ zipPrimExprsWith (Opaleye.BinExpr (Opaleye.OpOther operator)) a b
src/Rel8/Expr/Null.hs+26−39
@@ -5,11 +5,11 @@
55{-# options -fno-warn-redundant-constraints #-}
66
77module Rel8.Expr.Null
8− ( null, snull, nullable, nullableOf
8+ ( null, snull, nullableExpr, nullableOf
99 , isNull, isNonNull
1010 , nullify, unsafeUnnullify
11− , mapNullable, liftOpNullable
12− , unsafeMapNullable, unsafeLiftOpNullable
11+ , mapNull, liftOpNull
12+ , unsafeMapNull, unsafeLiftOpNull
1313 )
1414where
1515
@@ -23,7 +23,7 @@ import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
2323import {-# SOURCE #-} Rel8.Expr ( Expr( Expr ) )
2424import Rel8.Expr.Bool ( (||.), boolExpr )
2525import Rel8.Expr.Opaleye ( scastExpr, mapPrimExpr )
26−import Rel8.Schema.Nullability ( Nullability( Nullable ), IsMaybe )
26+import Rel8.Schema.Null ( NotNull )
2727import Rel8.Type ( DBType, typeInformation )
2828import Rel8.Type.Information ( TypeInformation )
2929
@@ -31,7 +31,7 @@ import Rel8.Type.Information ( TypeInformation )
3131-- | Lift an expression that can't be @null@ to a type that might be @null@.
3232-- This is an identity operation in terms of any generated query, and just
3333-- modifies the query's type.
34−nullify :: IsMaybe a ~ 'False => Expr a -> Expr (Maybe a)
34+nullify :: NotNull a => Expr a -> Expr (Maybe a)
3535nullify (Expr a) = Expr a
3636
3737
@@ -40,76 +40,63 @@ unsafeUnnullify (Expr a) = Expr a
4040
4141
4242-- | Like 'maybe', but to eliminate @null@.
43−--
44−-- >>> select c $ pure $ null 0 id (nullExpr :: Expr (Maybe Int32))
45−-- [0]
46−--
47−-- >>> select c $ pure $ null 0 id (lit (Just 42) :: Expr (Maybe Int32))
48−-- [42]
49−nullable :: Expr b -> (Expr a -> Expr b) -> Expr (Maybe a) -> Expr b
50−nullable b f ma = boolExpr (f (unsafeUnnullify ma)) b (isNull ma)
43+nullableExpr :: Expr b -> (Expr a -> Expr b) -> Expr (Maybe a) -> Expr b
44+nullableExpr b f ma = boolExpr (f (unsafeUnnullify ma)) b (isNull ma)
5145
5246
53−nullableOf :: (IsMaybe a ~ 'False, DBType a)
54− => Maybe (Expr a) -> Expr (Maybe a)
47+nullableOf :: DBType a => Maybe (Expr a) -> Expr (Maybe a)
5548nullableOf = maybe null nullify
5649
5750
58−-- | Like 'isNothing', but for @null@.
59−--
60−-- >>> select c $ pure $ isNull (nullExpr :: Expr (Maybe Int32))
61−-- [True]
62−--
63−-- >>> select c $ pure $ isNull (lit (Just 42) :: Expr (Maybe Int32))
64−-- [False]
51+-- | Like 'Data.Maybe.isNothing', but for @null@.
6552isNull :: Expr (Maybe a) -> Expr Bool
6653isNull = mapPrimExpr (Opaleye.UnExpr Opaleye.OpIsNull)
6754
6855
69−-- | Like 'isJust', but for @null@.
56+-- | Like 'Data.Maybe.isJust', but for @null@.
7057isNonNull :: Expr (Maybe a) -> Expr Bool
7158isNonNull = mapPrimExpr (Opaleye.UnExpr Opaleye.OpIsNotNull)
7259
7360
7461-- | Lift an operation on non-@null@ values to an operation on possibly @null@
75−-- values. When given @null@, @mapNullable f@ returns @null@.
62+-- values. When given @null@, @mapNull f@ returns @null@.
7663--
7764-- This is like 'fmap' for 'Maybe'.
78−mapNullable :: (IsMaybe b ~ 'False, DBType b)
65+mapNull :: DBType b
7966 => (Expr a -> Expr b) -> Expr (Maybe a) -> Expr (Maybe b)
80−mapNullable f ma = boolExpr (unsafeMapNullable f ma) null (isNull ma)
67+mapNull f ma = boolExpr (unsafeMapNull f ma) null (isNull ma)
8168
8269
8370-- | Lift a binary operation on non-@null@ expressions to an equivalent binary
8471-- operator on possibly @null@ expressions. If either of the final arguments
85−-- are @null@, @liftOpNullable@ returns @null@.
72+-- are @null@, @liftOpNull@ returns @null@.
8673--
8774-- This is like 'liftA2' for 'Maybe'.
88−liftOpNullable :: (IsMaybe c ~ 'False, DBType c)
75+liftOpNull :: DBType c
8976 => (Expr a -> Expr b -> Expr c)
9077 -> Expr (Maybe a) -> Expr (Maybe b) -> Expr (Maybe c)
91−liftOpNullable f ma mb =
92− boolExpr (unsafeLiftOpNullable f ma mb) null
78+liftOpNull f ma mb =
79+ boolExpr (unsafeLiftOpNull f ma mb) null
9380 (isNull ma ||. isNull mb)
81+{-# INLINABLE liftOpNull #-}
9482
9583
96−snull :: Nullability a (Maybe a) -> TypeInformation a -> Expr (Maybe a)
97−snull nullability info =
98− scastExpr nullability info $ Expr $ Opaleye.ConstExpr Opaleye.NullLit
84+snull :: TypeInformation a -> Expr (Maybe a)
85+snull info = scastExpr info $ Expr $ Opaleye.ConstExpr Opaleye.NullLit
9986
10087
10188-- | Corresponds to SQL @null@.
102−null :: (IsMaybe a ~ 'False, DBType a) => Expr (Maybe a)
103−null = snull Nullable typeInformation
89+null :: DBType a => Expr (Maybe a)
90+null = snull typeInformation
10491
10592
106−unsafeMapNullable :: IsMaybe b ~ 'False
93+unsafeMapNull :: NotNull b
10794 => (Expr a -> Expr b) -> Expr (Maybe a) -> Expr (Maybe b)
108−unsafeMapNullable f ma = nullify (f (unsafeUnnullify ma))
95+unsafeMapNull f ma = nullify (f (unsafeUnnullify ma))
10996
11097
111−unsafeLiftOpNullable :: IsMaybe c ~ 'False
98+unsafeLiftOpNull :: NotNull c
11299 => (Expr a -> Expr b -> Expr c)
113100 -> Expr (Maybe a) -> Expr (Maybe b) -> Expr (Maybe c)
114−unsafeLiftOpNullable f ma mb =
101+unsafeLiftOpNull f ma mb =
115102 nullify (f (unsafeUnnullify ma) (unsafeUnnullify mb))
src/Rel8/Expr/Num.hs+71−41
@@ -1,80 +1,110 @@
1+{-# language FlexibleContexts #-}
12{-# language TypeFamilies #-}
23
34{-# options_ghc -fno-warn-redundant-constraints #-}
45
56module Rel8.Expr.Num
6− ( fromIntegral, realToFrac, div, mod, ceiling, floor, round, truncate
7+ ( fromIntegral
8+ , realToFrac
9+ , div, mod, divMod
10+ , quot, rem, quotRem
11+ , ceiling, floor, round, truncate
712 )
813where
914
1015-- base
11−import Prelude ()
16+import Prelude ( (+), (-), fst, negate, signum, snd )
1217
1318-- rel
1419import Rel8.Expr ( Expr( Expr ) )
20+import Rel8.Expr.Eq ( (==.) )
1521import Rel8.Expr.Function ( function )
1622import Rel8.Expr.Opaleye ( castExpr )
17−import Rel8.Schema.Nullability ( IsMaybe, Nullabilizes )
23+import Rel8.Schema.Null ( Homonullable, Sql )
24+import Rel8.Table.Bool ( bool )
1825import Rel8.Type.Num ( DBFractional, DBIntegral, DBNum )
1926
2027
21−fromIntegral ::
22− ( DBIntegral _a, Nullabilizes _a a
23− , DBNum _b, Nullabilizes _b b
24− , IsMaybe a ~ IsMaybe b
25− )
28+-- | Cast 'DBIntegral' types to 'DBNum' types. For example, this can be useful
29+-- if you need to turn an @Expr Int32@ into an @Expr Double@.
30+fromIntegral :: (Sql DBIntegral a, Sql DBNum b, Homonullable a b)
2631 => Expr a -> Expr b
2732fromIntegral (Expr a) = castExpr (Expr a)
2833
2934
30−realToFrac ::
31− ( DBNum _a, Nullabilizes _a a
32− , DBFractional _b, Nullabilizes _b b
33− , IsMaybe a ~ IsMaybe b
34− )
35+-- | Cast 'DBNum' types to 'DBFractional' types. For example, his can be useful
36+-- to convert @Expr Float@ to @Expr Double@.
37+realToFrac :: (Sql DBNum a, Sql DBFractional b, Homonullable a b)
3538 => Expr a -> Expr b
3639realToFrac (Expr a) = castExpr (Expr a)
3740
3841
39−ceiling ::
40− ( DBFractional _a, Nullabilizes _a a
41− , DBIntegral _b, Nullabilizes _b b
42− , IsMaybe a ~ IsMaybe b
43− )
42+-- | Round a 'DBFractional' to a 'DBIntegral' by rounding to the nearest larger
43+-- integer.
44+--
45+-- Corresponds to the @ceiling()@ function.
46+ceiling :: (Sql DBFractional a, Sql DBIntegral b, Homonullable a b)
4447 => Expr a -> Expr b
45−ceiling = function "CEILING"
48+ceiling = function "ceiling"
4649
4750
48−div :: (DBIntegral _a, Nullabilizes _a a) => Expr a -> Expr a -> Expr a
49−div = function "DIV"
51+-- | Emulates the behaviour of the Haskell function 'Prelude.div' in
52+-- PostgreSQL.
53+div :: Sql DBIntegral a => Expr a -> Expr a -> Expr a
54+div n d = fst (divMod n d)
5055
5156
52−mod :: (DBIntegral _a, Nullabilizes _a a) => Expr a -> Expr a -> Expr a
53−mod = function "MOD"
57+-- | Emulates the behaviour of the Haskell function 'Prelude.mod' in
58+-- PostgreSQL.
59+mod :: Sql DBIntegral a => Expr a -> Expr a -> Expr a
60+mod n d = snd (divMod n d)
5461
5562
56−floor ::
57− ( DBFractional _a, Nullabilizes _a a
58− , DBIntegral _b, Nullabilizes _b b
59− , IsMaybe a ~ IsMaybe b
60− )
63+-- | Simultaneous 'div' and 'mod'.
64+divMod :: Sql DBIntegral a => Expr a -> Expr a -> (Expr a, Expr a)
65+divMod n d = bool qr (q - 1, r + d) (signum r ==. negate (signum d))
66+ where
67+ qr@(q, r) = quotRem n d
68+
69+
70+-- | Perform integral division. Corresponds to the @div()@ function in
71+-- PostgreSQL, which behaves like Haskell's 'Prelude.quot' rather than
72+-- 'Prelude.div'.
73+quot :: Sql DBIntegral a => Expr a -> Expr a -> Expr a
74+quot = function "div"
75+
76+
77+-- | Corresponds to the @mod()@ function in PostgreSQL, which behaves like
78+-- Haskell's 'Prelude.rem' rather than 'Prelude.mod'.
79+rem :: Sql DBIntegral a => Expr a -> Expr a -> Expr a
80+rem = function "mod"
81+
82+
83+-- | Simultaneous 'quot' and 'rem'.
84+quotRem :: Sql DBIntegral a => Expr a -> Expr a -> (Expr a, Expr a)
85+quotRem n d = (quot n d, rem n d)
86+
87+
88+-- | Round a 'DFractional' to a 'DBIntegral' by rounding to the nearest smaller
89+-- integer.
90+--
91+-- Corresponds to the @floor()@ function.
92+floor :: (Sql DBFractional a, Sql DBIntegral b, Homonullable a b)
6193 => Expr a -> Expr b
62−floor = function "FLOOR"
94+floor = function "floor"
6395
6496
65−round ::
66− ( DBFractional _a, Nullabilizes _a a
67− , DBIntegral _b, Nullabilizes _b b
68− , IsMaybe a ~ IsMaybe b
69− )
97+-- | Round a 'DBFractional' to a 'DBIntegral' by rounding to the nearest
98+-- integer.
99+--
100+-- Corresponds to the @round()@ function.
101+round :: (Sql DBFractional a, Sql DBIntegral b, Homonullable a b)
70102 => Expr a -> Expr b
71−round = function "ROUND"
103+round = function "round"
72104
73105
74−truncate ::
75− ( DBFractional _a, Nullabilizes _a a
76− , DBIntegral _b, Nullabilizes _b b
77− , IsMaybe a ~ IsMaybe b
78− )
106+-- | Round a 'DBFractional' to a 'DBIntegral' by rounding to the nearest
107+-- integer towards zero.
108+truncate :: (Sql DBFractional a, Sql DBIntegral b, Homonullable a b)
79109 => Expr a -> Expr b
80−truncate = function "TRUNC"
110+truncate = function "trunc"
src/Rel8/Expr/Opaleye.hs+29−15
@@ -1,8 +1,6 @@
11{-# language FlexibleContexts #-}
2−{-# language LambdaCase #-}
32{-# language NamedFieldPuns #-}
43{-# language ScopedTypeVariables #-}
5−{-# language TypeApplications #-}
64{-# language TypeFamilies #-}
75
86{-# options_ghc -fno-warn-redundant-constraints #-}
@@ -12,7 +10,7 @@ module Rel8.Expr.Opaleye
1210 , scastExpr, sunsafeCastExpr
1311 , unsafeLiteral
1412 , fromPrimExpr, toPrimExpr, mapPrimExpr, zipPrimExprsWith, traversePrimExpr
15− , toColumn, fromColumn
13+ , toColumn, fromColumn, traverseFieldP
1614 )
1715where
1816
@@ -25,31 +23,41 @@ import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
2523
2624-- rel8
2725import {-# SOURCE #-} Rel8.Expr ( Expr( Expr ) )
28−import Rel8.Schema.Nullability ( Nullability, Nullabilizes, nullabilization )
26+import Rel8.Schema.Null ( Unnullify, Sql )
2927import Rel8.Type ( DBType, typeInformation )
3028import Rel8.Type.Information ( TypeInformation(..) )
3129
30+-- profunctors
31+import Data.Profunctor ( Profunctor, dimap )
3232
33−castExpr :: (DBType db, Nullabilizes db a) => Expr a -> Expr a
34−castExpr = scastExpr nullabilization typeInformation
3533
34+castExpr :: Sql DBType a => Expr a -> Expr a
35+castExpr = scastExpr typeInformation
3636
37−unsafeCastExpr :: (DBType db, Nullabilizes db b) => Expr a -> Expr b
38−unsafeCastExpr = sunsafeCastExpr nullabilization typeInformation
3937
38+-- | Cast an expression to a different type. Corresponds to a @CAST()@ function
39+-- call.
40+unsafeCastExpr :: Sql DBType b => Expr a -> Expr b
41+unsafeCastExpr = sunsafeCastExpr typeInformation
4042
41−scastExpr :: Nullability db a -> TypeInformation db -> Expr a -> Expr a
43+
44+scastExpr :: TypeInformation (Unnullify a) -> Expr a -> Expr a
4245scastExpr = sunsafeCastExpr
4346
4447
4548sunsafeCastExpr :: ()
46− => Nullability db b -> TypeInformation db -> Expr a -> Expr b
47−sunsafeCastExpr _ TypeInformation {typeName} =
49+ => TypeInformation (Unnullify b) -> Expr a -> Expr b
50+sunsafeCastExpr TypeInformation {typeName} =
4851 fromPrimExpr . Opaleye.CastExpr typeName . toPrimExpr
4952
5053
51−unsafeLiteral :: (DBType db, Nullabilizes db a) => String -> Expr a
52−unsafeLiteral = castExpr . Expr . Opaleye.ConstExpr . Opaleye.OtherLit
54+-- | Unsafely construct an expression from literal SQL.
55+--
56+-- This is an escape hatch, and can be used if Rel8 can not adequately express
57+-- the query you need. If you find yourself using this function, please let us
58+-- know, as it may indicate that something is missing from Rel8!
59+unsafeLiteral :: String -> Expr a
60+unsafeLiteral = Expr . Opaleye.ConstExpr . Opaleye.OtherLit
5361
5462
5563fromPrimExpr :: Opaleye.PrimExpr -> Expr a
@@ -75,9 +83,15 @@ traversePrimExpr :: Functor f
7583traversePrimExpr f = fmap fromPrimExpr . f . toPrimExpr
7684
7785
78−toColumn :: Opaleye.PrimExpr -> Opaleye.Column b
86+traverseFieldP :: Profunctor p
87+ => p (Opaleye.Field_ n x) (Opaleye.Field_ m y)
88+ -> p (Expr a) (Expr b)
89+traverseFieldP = dimap (toColumn . toPrimExpr) (fromPrimExpr . fromColumn)
90+
91+
92+toColumn :: Opaleye.PrimExpr -> Opaleye.Field_ n b
7993toColumn = Opaleye.Column
8094
8195
82−fromColumn :: Opaleye.Column b -> Opaleye.PrimExpr
96+fromColumn :: Opaleye.Field_ n b -> Opaleye.PrimExpr
8397fromColumn (Opaleye.Column a) = a
src/Rel8/Expr/Ord.hs+64−57
@@ -1,5 +1,5 @@
11{-# language DataKinds #-}
2−{-# language LambdaCase #-}
2+{-# language FlexibleContexts #-}
33{-# language GADTs #-}
44{-# language ScopedTypeVariables #-}
55{-# language TypeApplications #-}
@@ -7,8 +7,7 @@
77{-# options_ghc -fno-warn-redundant-constraints #-}
88
99module Rel8.Expr.Ord
10− ( slt, sle, sgt, sge
11− , (<.), (<=.), (>.), (>=.)
10+ ( (<.), (<=.), (>.), (>=.)
1211 , (<?), (<=?), (>?), (>=?)
1312 , leastExpr, greatestExpr
1413 )
@@ -23,12 +22,9 @@ import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
2322-- rel8
2423import Rel8.Expr ( Expr( Expr ) )
2524import Rel8.Expr.Bool ( (&&.), (||.), coalesce )
26−import Rel8.Expr.Null ( isNull, isNonNull, nullable, unsafeLiftOpNullable )
27−import Rel8.Expr.Opaleye ( zipPrimExprsWith )
28−import Rel8.Schema.Nullability
29− ( Nullability( NonNullable, Nullable )
30− , Nullabilizes, nullabilization
31− )
25+import Rel8.Expr.Null ( isNull, isNonNull, nullableExpr, unsafeLiftOpNull )
26+import Rel8.Expr.Opaleye ( toPrimExpr, zipPrimExprsWith )
27+import Rel8.Schema.Null ( Nullity( Null, NotNull ), Sql, nullable )
3228import Rel8.Type.Ord ( DBOrd )
3329
3430
@@ -48,83 +44,94 @@ ge :: DBOrd a => Expr a -> Expr a -> Expr Bool
4844ge = zipPrimExprsWith (Opaleye.BinExpr (Opaleye.:>=))
4945
5046
51−slt :: DBOrd db => Nullability db a -> Expr a -> Expr a -> Expr Bool
52−slt = \case
53− Nullable -> \ma mb -> isNull ma &&. isNonNull mb ||. ma <? mb
54− NonNullable -> lt
55−
56−
57−sle :: DBOrd db => Nullability db a -> Expr a -> Expr a -> Expr Bool
58−sle = \case
59− Nullable -> \ma mb -> isNull ma ||. ma <=? mb
60− NonNullable -> le
61−
62−
63−sgt :: DBOrd db => Nullability db a -> Expr a -> Expr a -> Expr Bool
64−sgt = \case
65− Nullable -> \ma mb -> isNonNull ma &&. isNull mb ||. ma >? mb
66− NonNullable -> gt
67−
68−
69−sge :: DBOrd db => Nullability db a -> Expr a -> Expr a -> Expr Bool
70−sge = \case
71− Nullable -> \ma mb -> isNull mb ||. ma >=? mb
72− NonNullable -> ge
73−
74−
75−(<.) :: (DBOrd db, Nullabilizes db a) => Expr a -> Expr a -> Expr Bool
76−(<.) = slt nullabilization
47+-- | Corresponds to the SQL @<@ operator. Note that this differs from SQL @<@
48+-- as @null@ will sort below any other value. For a version of @<@ that exactly
49+-- matches SQL, see '(<?)'.
50+(<.) :: forall a. Sql DBOrd a => Expr a -> Expr a -> Expr Bool
51+(<.) = case nullable @a of
52+ Null -> \ma mb -> isNull ma &&. isNonNull mb ||. ma <? mb
53+ NotNull -> lt
7754infix 4 <.
7855
7956
80−(<=.) :: (DBOrd db, Nullabilizes db a) => Expr a -> Expr a -> Expr Bool
81−(<=.) = sle nullabilization
57+-- | Corresponds to the SQL @<=@ operator. Note that this differs from SQL @<=@
58+-- as @null@ will sort below any other value. For a version of @<=@ that exactly
59+-- matches SQL, see '(<=?)'.
60+(<=.) :: forall a. Sql DBOrd a => Expr a -> Expr a -> Expr Bool
61+(<=.) = case nullable @a of
62+ Null -> \ma mb -> isNull ma ||. ma <=? mb
63+ NotNull -> le
8264infix 4 <=.
8365
8466
85−(>.) :: (DBOrd db, Nullabilizes db a) => Expr a -> Expr a -> Expr Bool
86−(>.) = sgt nullabilization
67+-- | Corresponds to the SQL @>@ operator. Note that this differs from SQL @>@
68+-- as @null@ will sort below any other value. For a version of @>@ that exactly
69+-- matches SQL, see '(>?)'.
70+(>.) :: forall a. Sql DBOrd a => Expr a -> Expr a -> Expr Bool
71+(>.) = case nullable @a of
72+ Null -> \ma mb -> isNonNull ma &&. isNull mb ||. ma >? mb
73+ NotNull -> gt
8774infix 4 >.
8875
8976
90−(>=.) :: (DBOrd db, Nullabilizes db a) => Expr a -> Expr a -> Expr Bool
91−(>=.) = sge nullabilization
77+-- | Corresponds to the SQL @>=@ operator. Note that this differs from SQL @>@
78+-- as @null@ will sort below any other value. For a version of @>=@ that
79+-- exactly matches SQL, see '(>=?)'.
80+(>=.) :: forall a. Sql DBOrd a => Expr a -> Expr a -> Expr Bool
81+(>=.) = case nullable @a of
82+ Null -> \ma mb -> isNull mb ||. ma >=? mb
83+ NotNull -> ge
9284infix 4 >=.
9385
9486
87+-- | Corresponds to the SQL @<@ operator. Returns @null@ if either arguments
88+-- are @null@.
9589(<?) :: DBOrd a => Expr (Maybe a) -> Expr (Maybe a) -> Expr Bool
96−a <? b = coalesce $ unsafeLiftOpNullable lt a b
90+a <? b = coalesce $ unsafeLiftOpNull lt a b
9791infix 4 <?
9892
9993
94+-- | Corresponds to the SQL @<=@ operator. Returns @null@ if either arguments
95+-- are @null@.
10096(<=?) :: DBOrd a => Expr (Maybe a) -> Expr (Maybe a) -> Expr Bool
101−a <=? b = coalesce $ unsafeLiftOpNullable le a b
97+a <=? b = coalesce $ unsafeLiftOpNull le a b
10298infix 4 <=?
10399
104100
101+-- | Corresponds to the SQL @>@ operator. Returns @null@ if either arguments
102+-- are @null@.
105103(>?) :: DBOrd a => Expr (Maybe a) -> Expr (Maybe a) -> Expr Bool
106−a >? b = coalesce $ unsafeLiftOpNullable gt a b
104+a >? b = coalesce $ unsafeLiftOpNull gt a b
107105infix 4 >?
108106
109107
108+-- | Corresponds to the SQL @>=@ operator. Returns @null@ if either arguments
109+-- are @null@.
110110(>=?) :: DBOrd a => Expr (Maybe a) -> Expr (Maybe a) -> Expr Bool
111−a >=? b = coalesce $ unsafeLiftOpNullable ge a b
111+a >=? b = coalesce $ unsafeLiftOpNull ge a b
112112infix 4 >=?
113113
114114
115−leastExpr :: forall a db. (DBOrd db, Nullabilizes db a)
116− => Expr a -> Expr a -> Expr a
117−leastExpr ma mb = case nullabilization @a of
118− Nullable -> nullable ma (\a -> nullable mb (least_ a) mb) ma
119− NonNullable -> least_ ma mb
115+-- | Given two expressions, return the expression that sorts less than the
116+-- other.
117+--
118+-- Corresponds to the SQL @least()@ function.
119+leastExpr :: forall a. Sql DBOrd a => Expr a -> Expr a -> Expr a
120+leastExpr ma mb = case nullable @a of
121+ Null -> nullableExpr ma (\a -> nullableExpr mb (least_ a) mb) ma
122+ NotNull -> least_ ma mb
120123 where
121− least_ (Expr a) (Expr b) = Expr (Opaleye.FunExpr "LEAST" [a, b])
124+ least_ a b = Expr (Opaleye.FunExpr "LEAST" [toPrimExpr a, toPrimExpr b])
122125
123126
124−greatestExpr :: forall a db. (DBOrd db, Nullabilizes db a)
125− => Expr a -> Expr a -> Expr a
126−greatestExpr ma mb = case nullabilization @a of
127− Nullable -> nullable mb (\a -> nullable ma (greatest_ a) mb) ma
128− NonNullable -> greatest_ ma mb
127+-- | Given two expressions, return the expression that sorts greater than the
128+-- other.
129+--
130+-- Corresponds to the SQL @greatest()@ function.
131+greatestExpr :: forall a. Sql DBOrd a => Expr a -> Expr a -> Expr a
132+greatestExpr ma mb = case nullable @a of
133+ Null -> nullableExpr mb (\a -> nullableExpr ma (greatest_ a) mb) ma
134+ NotNull -> greatest_ ma mb
129135 where
130− greatest_ (Expr a) (Expr b) = Expr (Opaleye.FunExpr "GREATEST" [a, b])
136+ greatest_ a b =
137+ Expr (Opaleye.FunExpr "GREATEST" [toPrimExpr a, toPrimExpr b])
src/Rel8/Expr/Order.hs+6
@@ -27,6 +27,7 @@ import Rel8.Order ( Order( Order ) )
2727import Rel8.Type.Ord ( DBOrd )
2828
2929
30+-- | Sort a column in ascending order.
3031asc :: DBOrd a => Order (Expr a)
3132asc = Order $ Opaleye.Order (\expr -> [(orderOp, toPrimExpr expr)])
3233 where
@@ -37,6 +38,7 @@ asc = Order $ Opaleye.Order (\expr -> [(orderOp, toPrimExpr expr)])
3738 }
3839
3940
41+-- | Sort a column in descending order.
4042desc :: DBOrd a => Order (Expr a)
4143desc = Order $ Opaleye.Order (\expr -> [(orderOp, toPrimExpr expr)])
4244 where
@@ -47,6 +49,8 @@ desc = Order $ Opaleye.Order (\expr -> [(orderOp, toPrimExpr expr)])
4749 }
4850
4951
52+-- | Transform an ordering so that @null@ values appear first. This corresponds
53+-- to @NULLS FIRST@ in SQL.
5054nullsFirst :: Order (Expr a) -> Order (Expr (Maybe a))
5155nullsFirst (Order (Opaleye.Order f)) =
5256 Order $ Opaleye.Order $ fmap (first g) . f . unsafeUnnullify
@@ -55,6 +59,8 @@ nullsFirst (Order (Opaleye.Order f)) =
5559 g orderOp = orderOp { Opaleye.orderNulls = Opaleye.NullsFirst }
5660
5761
62+-- | Transform an ordering so that @null@ values appear first. This corresponds
63+-- to @NULLS LAST@ in SQL.
5864nullsLast :: Order (Expr a) -> Order (Expr (Maybe a))
5965nullsLast (Order (Opaleye.Order f)) =
6066 Order $ Opaleye.Order $ fmap (first g) . f . unsafeUnnullify
src/Rel8/Expr/Sequence.hsnew file+22
@@ -0,0 +1,22 @@
1+module Rel8.Expr.Sequence
2+ ( nextval
3+ )
4+where
5+
6+-- base
7+import Data.Int ( Int64 )
8+import Prelude
9+
10+-- rel8
11+import Rel8.Expr ( Expr )
12+import Rel8.Expr.Function ( function )
13+import Rel8.Expr.Serialize ( litExpr )
14+import Rel8.Expr.Text ( quoteIdent )
15+
16+-- text
17+import Data.Text ( pack )
18+
19+
20+-- | See https://www.postgresql.org/docs/current/functions-sequence.html
21+nextval :: String -> Expr Int64
22+nextval = function "nextval" . quoteIdent . litExpr . pack
src/Rel8/Expr/Serialize.hs+18−16
@@ -1,3 +1,4 @@
1+{-# language FlexibleContexts #-}
12{-# language NamedFieldPuns #-}
23{-# language TypeFamilies #-}
34
@@ -20,28 +21,29 @@ import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
2021-- rel8
2122import {-# SOURCE #-} Rel8.Expr ( Expr( Expr ) )
2223import Rel8.Expr.Opaleye ( scastExpr )
23−import Rel8.Schema.Nullability
24− ( Nullability( Nullable, NonNullable )
25− , Nullabilizes, nullabilization
26− )
24+import Rel8.Schema.Null ( Unnullify, Nullity( Null, NotNull ), Sql, nullable )
2725import Rel8.Type ( DBType, typeInformation )
2826import Rel8.Type.Information ( TypeInformation(..) )
2927
3028
31−litExpr :: (DBType db, Nullabilizes db a) => a -> Expr a
32−litExpr = slitExpr nullabilization typeInformation
29+-- | Produce an expression from a literal.
30+--
31+-- Note that you can usually use 'Rel8.lit', but @litExpr@ can solve problems
32+-- of inference in polymorphic code.
33+litExpr :: Sql DBType a => a -> Expr a
34+litExpr = slitExpr nullable typeInformation
3335
3436
35−slitExpr :: Nullability db a -> TypeInformation db -> a -> Expr a
36−slitExpr nullable info@TypeInformation {encode} =
37− scastExpr nullable info . Expr . encoder
37+slitExpr :: Nullity a -> TypeInformation (Unnullify a) -> a -> Expr a
38+slitExpr nullity info@TypeInformation {encode} =
39+ scastExpr info . Expr . encoder
3840 where
39− encoder = case nullable of
40− Nullable -> maybe (Opaleye.ConstExpr Opaleye.NullLit) encode
41− NonNullable -> encode
41+ encoder = case nullity of
42+ Null -> maybe (Opaleye.ConstExpr Opaleye.NullLit) encode
43+ NotNull -> encode
4244
4345
44−sparseValue :: Nullability db a -> TypeInformation db -> Hasql.Row a
45−sparseValue nullability TypeInformation {decode, out} = case nullability of
46− Nullable -> Hasql.column $ Hasql.nullable $ out <$> decode
47− NonNullable -> Hasql.column $ Hasql.nonNullable $ out <$> decode
46+sparseValue :: Nullity a -> TypeInformation (Unnullify a) -> Hasql.Row a
47+sparseValue nullity TypeInformation {decode} = case nullity of
48+ Null -> Hasql.column $ Hasql.nullable decode
49+ NotNull -> Hasql.column $ Hasql.nonNullable decode
src/Rel8/Expr/Text.hs+66−11
@@ -16,7 +16,10 @@ module Rel8.Expr.Text
1616 , initcap, left, length, lengthEncoding, lpad, ltrim, md5
1717 , pgClientEncoding, quoteIdent, quoteLiteral, quoteNullable, regexpReplace
1818 , regexpSplitToArray, repeat, replace, reverse, right, rpad, rtrim
19− , splitPart, strpos, substr, toAscii, toHex, translate
19+ , splitPart, strpos, substr, translate
20+
21+ -- * @LIKE@ and @ILIKE@
22+ , like, ilike
2023 )
2124where
2225
@@ -24,7 +27,7 @@ where
2427import Data.Bool ( Bool )
2528import Data.Int ( Int32 )
2629import Data.Maybe ( Maybe( Nothing, Just ) )
27−import Prelude ()
30+import Prelude ( flip )
2831
2932-- bytestring
3033import Data.ByteString ( ByteString )
@@ -32,7 +35,6 @@ import Data.ByteString ( ByteString )
3235-- rel8
3336import Rel8.Expr ( Expr )
3437import Rel8.Expr.Function ( binaryOperator, function, nullaryFunction )
35−import Rel8.Type.Array1D ( Array1D )
3638
3739-- text
3840import Data.Text (Text)
@@ -50,24 +52,32 @@ infixr 6 ++.
5052
5153
5254-- | Matches regular expression, case sensitive
55+--
56+-- Corresponds to the @~.@ operator.
5357(~.) :: Expr Text -> Expr Text -> Expr Bool
5458(~.) = binaryOperator "~."
5559infix 2 ~.
5660
5761
5862-- | Matches regular expression, case insensitive
63+--
64+-- Corresponds to the @~*@ operator.
5965(~*) :: Expr Text -> Expr Text -> Expr Bool
6066(~*) = binaryOperator "~*"
6167infix 2 ~*
6268
6369
6470-- | Does not match regular expression, case sensitive
71+--
72+-- Corresponds to the @!~@ operator.
6573(!~) :: Expr Text -> Expr Text -> Expr Bool
6674(!~) = binaryOperator "!~"
6775infix 2 !~
6876
6977
7078-- | Does not match regular expression, case insensitive
79+--
80+-- Corresponds to the @!~*@ operator.
7181(!~*) :: Expr Text -> Expr Text -> Expr Bool
7282(!~*) = binaryOperator "!~*"
7383infix 2 !~*
@@ -78,164 +88,209 @@ infix 2 !~*
7888-- * Standard SQL functions
7989
8090
91+-- | Corresponds to the @bit_length@ function.
8192bitLength :: Expr Text -> Expr Int32
8293bitLength = function "bit_length"
8394
8495
96+-- | Corresponds to the @char_length@ function.
8597charLength :: Expr Text -> Expr Int32
8698charLength = function "char_length"
8799
88100
101+-- | Corresponds to the @lower@ function.
89102lower :: Expr Text -> Expr Text
90103lower = function "lower"
91104
92105
106+-- | Corresponds to the @octet_length@ function.
93107octetLength :: Expr Text -> Expr Int32
94108octetLength = function "octet_length"
95109
96110
111+-- | Corresponds to the @upper@ function.
97112upper :: Expr Text -> Expr Text
98113upper = function "upper"
99114
100115
101−-- * PostgreSQL functions
116+-- | Corresponds to the @ascii@ function.
102117ascii :: Expr Text -> Expr Int32
103118ascii = function "ascii"
104119
105120
121+-- | Corresponds to the @btrim@ function.
106122btrim :: Expr Text -> Maybe (Expr Text) -> Expr Text
107123btrim a (Just b) = function "btrim" a b
108124btrim a Nothing = function "btrim" a
109125
110126
127+-- | Corresponds to the @chr@ function.
111128chr :: Expr Int32 -> Expr Text
112129chr = function "chr"
113130
114131
132+-- | Corresponds to the @convert@ function.
115133convert :: Expr ByteString -> Expr Text -> Expr Text -> Expr ByteString
116134convert = function "convert"
117135
118136
137+-- | Corresponds to the @convert_from@ function.
119138convertFrom :: Expr ByteString -> Expr Text -> Expr Text
120139convertFrom = function "convert_from"
121140
122141
142+-- | Corresponds to the @convert_to@ function.
123143convertTo :: Expr Text -> Expr Text -> Expr ByteString
124144convertTo = function "convert_to"
125145
126146
147+-- | Corresponds to the @decode@ function.
127148decode :: Expr Text -> Expr Text -> Expr ByteString
128149decode = function "decode"
129150
130151
152+-- | Corresponds to the @encode@ function.
131153encode :: Expr ByteString -> Expr Text -> Expr Text
132154encode = function "encode"
133155
134156
157+-- | Corresponds to the @initcap@ function.
135158initcap :: Expr Text -> Expr Text
136159initcap = function "initcap"
137160
138161
162+-- | Corresponds to the @left@ function.
139163left :: Expr Text -> Expr Int32 -> Expr Text
140164left = function "left"
141165
142166
167+-- | Corresponds to the @length@ function.
143168length :: Expr Text -> Expr Int32
144169length = function "length"
145170
146171
172+-- | Corresponds to the @length@ function.
147173lengthEncoding :: Expr ByteString -> Expr Text -> Expr Int32
148174lengthEncoding = function "length"
149175
150176
177+-- | Corresponds to the @lpad@ function.
151178lpad :: Expr Text -> Expr Int32 -> Maybe (Expr Text) -> Expr Text
152179lpad a b (Just c) = function "lpad" a b c
153180lpad a b Nothing = function "lpad" a b
154181
155182
183+-- | Corresponds to the @ltrim@ function.
156184ltrim :: Expr Text -> Maybe (Expr Text) -> Expr Text
157185ltrim a (Just b) = function "ltrim" a b
158186ltrim a Nothing = function "ltrim" a
159187
160188
189+-- | Corresponds to the @md5@ function.
161190md5 :: Expr Text -> Expr Text
162191md5 = function "md5"
163192
164193
194+-- | Corresponds to the @pg_client_encoding()@ expression.
165195pgClientEncoding :: Expr Text
166196pgClientEncoding = nullaryFunction "pg_client_encoding"
167197
168198
199+-- | Corresponds to the @quote_ident@ function.
169200quoteIdent :: Expr Text -> Expr Text
170201quoteIdent = function "quote_ident"
171202
172203
204+-- | Corresponds to the @quote_literal@ function.
173205quoteLiteral :: Expr Text -> Expr Text
174206quoteLiteral = function "quote_literal"
175207
176208
209+-- | Corresponds to the @quote_nullable@ function.
177210quoteNullable :: Expr Text -> Expr Text
178211quoteNullable = function "quote_nullable"
179212
180213
214+-- | Corresponds to the @regexp_replace@ function.
181215regexpReplace :: ()
182216 => Expr Text -> Expr Text -> Expr Text -> Maybe (Expr Text) -> Expr Text
183217regexpReplace a b c (Just d) = function "regexp_replace" a b c d
184218regexpReplace a b c Nothing = function "regexp_replace" a b c
185219
186220
221+-- | Corresponds to the @regexp_split_to_array@ function.
187222regexpSplitToArray :: ()
188− => Expr Text -> Expr Text -> Maybe (Expr Text) -> Expr (Array1D Text)
223+ => Expr Text -> Expr Text -> Maybe (Expr Text) -> Expr [Text]
189224regexpSplitToArray a b (Just c) = function "regexp_split_to_array" a b c
190225regexpSplitToArray a b Nothing = function "regexp_split_to_array" a b
191226
192227
228+-- | Corresponds to the @repeat@ function.
193229repeat :: Expr Text -> Expr Int32 -> Expr Text
194230repeat = function "repeat"
195231
196232
233+-- | Corresponds to the @replace@ function.
197234replace :: Expr Text -> Expr Text -> Expr Text -> Expr Text
198235replace = function "replace"
199236
200237
238+-- | Corresponds to the @reverse@ function.
201239reverse :: Expr Text -> Expr Text
202240reverse = function "reverse"
203241
204242
243+-- | Corresponds to the @right@ function.
205244right :: Expr Text -> Expr Int32 -> Expr Text
206245right = function "right"
207246
208247
248+-- | Corresponds to the @rpad@ function.
209249rpad :: Expr Text -> Expr Int32 -> Maybe (Expr Text) -> Expr Text
210250rpad a b (Just c) = function "rpad" a b c
211251rpad a b Nothing = function "rpad" a b
212252
213253
254+-- | Corresponds to the @rtrim@ function.
214255rtrim :: Expr Text -> Maybe (Expr Text) -> Expr Text
215256rtrim a (Just b) = function "rtrim" a b
216257rtrim a Nothing = function "rtrim" a
217258
218259
260+-- | Corresponds to the @split_part@ function.
219261splitPart :: Expr Text -> Expr Text -> Expr Int32 -> Expr Text
220262splitPart = function "split_part"
221263
222264
265+-- | Corresponds to the @strpos@ function.
223266strpos :: Expr Text -> Expr Text -> Expr Int32
224267strpos = function "strpos"
225268
226269
270+-- | Corresponds to the @substr@ function.
227271substr :: Expr Text -> Expr Int32 -> Maybe (Expr Int32) -> Expr Text
228272substr a b (Just c) = function "substr" a b c
229273substr a b Nothing = function "substr" a b
230274
231275
232−toAscii :: Expr Text -> Expr Text -> Expr Text
233−toAscii = function "toAscii"
276+-- | Corresponds to the @translate@ function.
277+translate :: Expr Text -> Expr Text -> Expr Text -> Expr Text
278+translate = function "translate"
234279
235280
236−toHex :: Expr Int32 -> Expr Text
237−toHex = function "toHex"
281+-- | @like x y@ corresponds to the expression @y LIKE x@.
282+--
283+-- Note that the arguments to @like@ are swapped. This is to aid currying, so
284+-- you can write expressions like
285+-- @filter (like "Rel%" . packageName) =<< each haskellPackages@
286+like :: Expr Text -> Expr Text -> Expr Bool
287+like = flip (binaryOperator "LIKE")
238288
239289
240−translate :: Expr Text -> Expr Text -> Expr Text -> Expr Text
241−translate = function "translate"
290+-- | @ilike x y@ corresponds to the expression @y ILIKE x@.
291+--
292+-- Note that the arguments to @ilike@ are swapped. This is to aid currying, so
293+-- you can write expressions like
294+-- @filter (ilike "Rel%" . packageName) =<< each haskellPackages@
295+ilike :: Expr Text -> Expr Text -> Expr Bool
296+ilike = flip (binaryOperator "ILIKE")
src/Rel8/Expr/Time.hs+36−24
@@ -13,12 +13,13 @@ module Rel8.Expr.Time
1313 , diffTime
1414 , subtractTime
1515
16− -- Working with @DiffTime@
16+ -- * Working with @CalendarDiffTime@
1717 , scaleInterval
1818 , second, seconds
1919 , minute, minutes
2020 , hour, hours
2121 , day, days
22+ , week, weeks
2223 , month, months
2324 , year, years
2425 ) where
@@ -30,11 +31,12 @@ import Prelude
3031-- rel8
3132import Rel8.Expr ( Expr )
3233import Rel8.Expr.Function ( binaryOperator, nullaryFunction )
33−import Rel8.Expr.Opaleye ( unsafeCastExpr, unsafeLiteral )
34+import Rel8.Expr.Opaleye ( castExpr, unsafeCastExpr, unsafeLiteral )
3435
3536-- time
3637import Data.Time.Calendar ( Day )
37−import Data.Time.Clock ( DiffTime, UTCTime )
38+import Data.Time.Clock ( UTCTime )
39+import Data.Time.LocalTime ( CalendarDiffTime )
3840
3941
4042-- | Corresponds to @date(now())@.
@@ -73,83 +75,93 @@ now = nullaryFunction "now"
7375
7476
7577-- | Add a time interval to a point in time, yielding a new point in time.
76−addTime :: Expr DiffTime -> Expr UTCTime -> Expr UTCTime
78+addTime :: Expr CalendarDiffTime -> Expr UTCTime -> Expr UTCTime
7779addTime = flip (binaryOperator "+")
7880
7981
8082-- | Find the duration between two times.
81−diffTime :: Expr UTCTime -> Expr UTCTime -> Expr DiffTime
83+diffTime :: Expr UTCTime -> Expr UTCTime -> Expr CalendarDiffTime
8284diffTime = binaryOperator "-"
8385
8486
8587-- | Subtract a time interval from a point in time, yielding a new point in time.
86−subtractTime :: Expr DiffTime -> Expr UTCTime -> Expr UTCTime
88+subtractTime :: Expr CalendarDiffTime -> Expr UTCTime -> Expr UTCTime
8789subtractTime = flip (binaryOperator "-")
8890
8991
90−scaleInterval :: Expr Double -> Expr DiffTime -> Expr DiffTime
92+scaleInterval :: Expr Double -> Expr CalendarDiffTime -> Expr CalendarDiffTime
9193scaleInterval = binaryOperator "*"
9294
9395
9496-- | An interval of one second.
95−second :: Expr DiffTime
97+second :: Expr CalendarDiffTime
9698second = singleton "second"
9799
98100
99−-- | Create a literal interval from an integral number of seconds.
100−seconds :: Expr Double -> Expr DiffTime
101+-- | Create a literal interval from a number of seconds.
102+seconds :: Expr Double -> Expr CalendarDiffTime
101103seconds = (`scaleInterval` second)
102104
103105
104106-- | An interval of one minute.
105−minute :: Expr DiffTime
107+minute :: Expr CalendarDiffTime
106108minute = singleton "minute"
107109
108110
109−-- | Create a literal interval from an integral number of minutes.
110−minutes :: Expr Double -> Expr DiffTime
111+-- | Create a literal interval from a number of minutes.
112+minutes :: Expr Double -> Expr CalendarDiffTime
111113minutes = (`scaleInterval` minute)
112114
113115
114116-- | An interval of one hour.
115−hour :: Expr DiffTime
117+hour :: Expr CalendarDiffTime
116118hour = singleton "hour"
117119
118120
119−-- | Create a literal interval from an integral number of hours.
120−hours :: Expr Double -> Expr DiffTime
121+-- | Create a literal interval from a number of hours.
122+hours :: Expr Double -> Expr CalendarDiffTime
121123hours = (`scaleInterval` hour)
122124
123125
124126-- | An interval of one day.
125−day :: Expr DiffTime
127+day :: Expr CalendarDiffTime
126128day = singleton "day"
127129
128130
129131-- | Create a literal interval from a number of days.
130−days :: Expr Double -> Expr DiffTime
132+days :: Expr Double -> Expr CalendarDiffTime
131133days = (`scaleInterval` day)
132134
133135
136+-- | An interval of one week.
137+week :: Expr CalendarDiffTime
138+week = singleton "week"
139+
140+
141+-- | Create a literal interval from a number of weeks.
142+weeks :: Expr Double -> Expr CalendarDiffTime
143+weeks = (`scaleInterval` week)
144+
145+
134146-- | An interval of one month.
135−month :: Expr DiffTime
147+month :: Expr CalendarDiffTime
136148month = singleton "month"
137149
138150
139151-- | Create a literal interval from a number of months.
140−months :: Expr Double -> Expr DiffTime
152+months :: Expr Double -> Expr CalendarDiffTime
141153months = (`scaleInterval` month)
142154
143155
144156-- | An interval of one year.
145−year :: Expr DiffTime
157+year :: Expr CalendarDiffTime
146158year = singleton "year"
147159
148160
149161-- | Create a literal interval from a number of years.
150−years :: Expr Double -> Expr DiffTime
162+years :: Expr Double -> Expr CalendarDiffTime
151163years = (`scaleInterval` year)
152164
153165
154−singleton :: String -> Expr DiffTime
155−singleton unit = unsafeLiteral $ "'1 " ++ unit ++ "'"
166+singleton :: String -> Expr CalendarDiffTime
167+singleton unit = castExpr $ unsafeLiteral $ "'1 " ++ unit ++ "'"
src/Rel8/Expr/Window.hsnew file+121
@@ -0,0 +1,121 @@
1+module Rel8.Expr.Window
2+ ( cumulative
3+ , rowNumber
4+ , rank
5+ , denseRank
6+ , percentRank
7+ , cumeDist
8+ , ntile
9+ , lag
10+ , lead
11+ , firstValue
12+ , lastValue
13+ , nthValue
14+ )
15+where
16+
17+-- base
18+import Data.Int ( Int32, Int64 )
19+import Prelude
20+
21+-- opaleye
22+import qualified Opaleye.Internal.Aggregate as Opaleye
23+import qualified Opaleye.Internal.PackMap as Opaleye
24+import qualified Opaleye.Internal.Window as Opaleye
25+import qualified Opaleye.Window as Opaleye
26+
27+-- profunctors
28+import Data.Profunctor (dimap)
29+
30+-- rel8
31+import Rel8.Aggregate ( Aggregate( Aggregate ) )
32+import Rel8.Expr ( Expr )
33+import Rel8.Expr.Opaleye ( fromColumn, fromPrimExpr, toColumn, toPrimExpr )
34+import Rel8.Schema.Null ( Nullify )
35+import Rel8.Window ( Window( Window ) )
36+
37+
38+cumulative :: (a -> Aggregate b) -> Window a (Expr b)
39+cumulative f =
40+ fromWindowFunction $ Opaleye.aggregatorWindowFunction (fromAggregate f) id
41+
42+
43+-- | [@row_number()@](https://www.postgresql.org/docs/current/functions-window.html)
44+rowNumber :: Window a (Expr Int64)
45+rowNumber = fromWindowFunction $ fromPrimExpr . fromColumn <$> Opaleye.rowNumber
46+
47+
48+-- | [@rank()@](https://www.postgresql.org/docs/current/functions-window.html)
49+rank :: Window a (Expr Int64)
50+rank = fromWindowFunction $ fromPrimExpr . fromColumn <$> Opaleye.rank
51+
52+
53+-- | [@dense_rank()@](https://www.postgresql.org/docs/current/functions-window.html)
54+denseRank :: Window a (Expr Int64)
55+denseRank = fromWindowFunction $ fromPrimExpr . fromColumn <$> Opaleye.denseRank
56+
57+
58+-- | [@percent_rank()@](https://www.postgresql.org/docs/current/functions-window.html)
59+percentRank :: Window a (Expr Double)
60+percentRank = fromWindowFunction $ fromPrimExpr . fromColumn <$> Opaleye.percentRank
61+
62+
63+-- | [@cume_dist()@](https://www.postgresql.org/docs/current/functions-window.html)
64+cumeDist :: Window a (Expr Double)
65+cumeDist = fromWindowFunction $ fromPrimExpr . fromColumn <$> Opaleye.cumeDist
66+
67+
68+-- | [@ntile(num_buckets)@](https://www.postgresql.org/docs/current/functions-window.html)
69+ntile :: Expr Int32 -> Window a (Expr Int32)
70+ntile buckets = fromWindowFunction $ fromPrimExpr . fromColumn <$>
71+ Opaleye.ntile (toColumn (toPrimExpr buckets))
72+
73+
74+-- | [@lag(value, offset, default)@](https://www.postgresql.org/docs/current/functions-window.html)
75+lag :: Expr Int32 -> Expr a -> Window (Expr a) (Expr a)
76+lag offset def =
77+ fromWindowFunction $
78+ dimap (toColumn . toPrimExpr) (fromPrimExpr . fromColumn) $
79+ Opaleye.lag (toColumn (toPrimExpr offset)) (toColumn (toPrimExpr def))
80+
81+
82+-- | [@lead(value, offset, default)@](https://www.postgresql.org/docs/current/functions-window.html)
83+lead :: Expr Int32 -> Expr a -> Window (Expr a) (Expr a)
84+lead offset def =
85+ fromWindowFunction $
86+ dimap (toColumn . toPrimExpr) (fromPrimExpr . fromColumn) $
87+ Opaleye.lead (toColumn (toPrimExpr offset)) (toColumn (toPrimExpr def))
88+
89+
90+-- | [@first_value(value)@](https://www.postgresql.org/docs/current/functions-window.html)
91+firstValue :: Window (Expr a) (Expr a)
92+firstValue =
93+ fromWindowFunction $
94+ dimap (toColumn . toPrimExpr) (fromPrimExpr . fromColumn)
95+ Opaleye.firstValue
96+
97+
98+-- | [@last_value(value)@](https://www.postgresql.org/docs/current/functions-window.html)
99+lastValue :: Window (Expr a) (Expr a)
100+lastValue =
101+ fromWindowFunction $
102+ dimap (toColumn . toPrimExpr) (fromPrimExpr . fromColumn)
103+ Opaleye.lastValue
104+
105+
106+-- | [@nth_value(value, n)@](https://www.postgresql.org/docs/current/functions-window.html)
107+nthValue :: Expr Int32 -> Window (Expr a) (Expr (Nullify a))
108+nthValue n =
109+ fromWindowFunction $
110+ dimap (toColumn . toPrimExpr) (fromPrimExpr . fromColumn) $
111+ Opaleye.nthValue (toColumn (toPrimExpr n))
112+
113+
114+fromAggregate :: (a -> Aggregate b) -> Opaleye.Aggregator a (Expr b)
115+fromAggregate f = Opaleye.Aggregator $ Opaleye.PackMap $ \w a -> case f a of
116+ Aggregate (Opaleye.Aggregator (Opaleye.PackMap x)) -> x w ()
117+
118+
119+fromWindowFunction :: Opaleye.WindowFunction a b -> Window a b
120+fromWindowFunction (Opaleye.WindowFunction (Opaleye.PackMap w)) =
121+ Window $ Opaleye.Windows $ Opaleye.PackMap $ \f -> w $ \o -> f (o, mempty)
src/Rel8/FCF.hsnew file+26
@@ -0,0 +1,26 @@
1+{-# language DataKinds #-}
2+{-# language PolyKinds #-}
3+{-# language StandaloneKindSignatures #-}
4+{-# language TypeFamilies #-}
5+
6+module Rel8.FCF
7+ ( Exp, Eval
8+ , Id
9+ )
10+where
11+
12+-- base
13+import Data.Kind ( Type )
14+import Prelude ()
15+
16+
17+type Exp :: Type -> Type
18+type Exp e = e -> Type
19+
20+
21+type Eval :: Exp e -> e
22+type family Eval a
23+
24+
25+data Id :: a -> Exp a
26+type instance Eval (Id a) = a
src/Rel8/Generic/Construction.hsnew file+352
@@ -0,0 +1,352 @@
1+{-# language AllowAmbiguousTypes #-}
2+{-# language ConstraintKinds #-}
3+{-# language DataKinds #-}
4+{-# language FlexibleContexts #-}
5+{-# language NamedFieldPuns #-}
6+{-# language ScopedTypeVariables #-}
7+{-# language StandaloneKindSignatures #-}
8+{-# language TypeApplications #-}
9+{-# language TypeFamilies #-}
10+{-# language UndecidableInstances #-}
11+{-# language ViewPatterns #-}
12+
13+module Rel8.Generic.Construction
14+ ( GGBuildable
15+ , GGBuild, ggbuild
16+ , GGConstructable
17+ , GGConstruct, ggconstruct
18+ , GGDeconstruct, ggdeconstruct
19+ , GGName, ggname
20+ , GGAggregate, ggaggregate
21+ )
22+where
23+
24+-- base
25+import Data.Bifunctor ( first )
26+import Data.Kind ( Constraint, Type )
27+import Data.List.NonEmpty ( NonEmpty( (:|) ) )
28+import GHC.TypeLits ( Symbol )
29+import Prelude
30+
31+-- rel8
32+import Rel8.Aggregate ( Aggregate( Aggregate ) )
33+import Rel8.Expr ( Expr )
34+import Rel8.Expr.Aggregate ( groupByExpr )
35+import Rel8.Expr.Eq ( (==.) )
36+import Rel8.Expr.Null ( nullify, snull, unsafeUnnullify )
37+import Rel8.Expr.Serialize ( litExpr )
38+import Rel8.FCF ( Eval, Exp, Id )
39+import Rel8.Generic.Construction.ADT
40+ ( GConstructorADT, GMakeableADT, gmakeADT
41+ , GConstructableADT
42+ , GBuildADT, gbuildADT, gunbuildADT
43+ , GConstructADT, gconstructADT, gdeconstructADT
44+ , RepresentableConstructors, GConstructors, gcindex, gctabulate
45+ , RepresentableFields, gfindex, gftabulate
46+ )
47+import Rel8.Generic.Construction.Record
48+ ( GConstructor
49+ , GConstructable, GConstruct, gconstruct, gdeconstruct
50+ , Representable, gindex, gtabulate
51+ )
52+import Rel8.Generic.Table ( GGColumns )
53+import Rel8.Kind.Algebra
54+ ( SAlgebra( SProduct, SSum )
55+ , KnownAlgebra, algebraSing
56+ )
57+import qualified Rel8.Kind.Algebra as K
58+import Rel8.Schema.Context.Nullify ( sguard, snullify )
59+import Rel8.Schema.HTable ( HTable )
60+import Rel8.Schema.HTable.Identity ( HIdentity( HIdentity ) )
61+import qualified Rel8.Schema.Kind as K
62+import Rel8.Schema.Name ( Name( Name ) )
63+import Rel8.Schema.Null ( Nullity( Null, NotNull ) )
64+import Rel8.Schema.Spec ( Spec( Spec, nullity, info ) )
65+import Rel8.Table
66+ ( TTable, TColumns
67+ , Table, fromColumns, toColumns
68+ )
69+import Rel8.Table.Bool ( case_ )
70+import Rel8.Type.Tag ( Tag )
71+
72+
73+type GGBuildable :: K.Algebra -> Symbol -> (K.Context -> Exp (Type -> Type)) -> Constraint
74+type GGBuildable algebra name rep =
75+ ( KnownAlgebra algebra
76+ , Eval (GGColumns algebra TColumns (Eval (rep Aggregate))) ~ Eval (GGColumns algebra TColumns (Eval (rep Expr)))
77+ , Eval (GGColumns algebra TColumns (Eval (rep Expr))) ~ Eval (GGColumns algebra TColumns (Eval (rep Expr)))
78+ , Eval (GGColumns algebra TColumns (Eval (rep Name))) ~ Eval (GGColumns algebra TColumns (Eval (rep Expr)))
79+ , HTable (Eval (GGColumns algebra TColumns (Eval (rep Expr))))
80+ , GGBuildable' algebra name rep
81+ )
82+
83+
84+type GGBuildable' :: K.Algebra -> Symbol -> (K.Context -> Exp (Type -> Type)) -> Constraint
85+type family GGBuildable' algebra name rep where
86+ GGBuildable' 'K.Product name rep =
87+ ( name ~ GConstructor (Eval (rep Expr))
88+ , Representable Id (Eval (rep Expr))
89+ , GConstructable (TTable Expr) TColumns Id Expr (Eval (rep Expr))
90+ )
91+ GGBuildable' 'K.Sum name rep =
92+ ( Representable Id (GConstructorADT name (Eval (rep Expr)))
93+ , GMakeableADT (TTable Expr) TColumns Id Expr name (Eval (rep Expr))
94+ )
95+
96+
97+type GGBuild :: K.Algebra -> Symbol -> (K.Context -> Exp (Type -> Type)) -> Type -> Type
98+type family GGBuild algebra name rep r where
99+ GGBuild 'K.Product _name rep r =
100+ GConstruct Id (Eval (rep Expr)) r
101+ GGBuild 'K.Sum name rep r =
102+ GConstruct Id (GConstructorADT name (Eval (rep Expr))) r
103+
104+
105+ggbuild :: forall algebra name rep a. GGBuildable algebra name rep
106+ => (Eval (GGColumns algebra TColumns (Eval (rep Expr))) Expr -> a)
107+ -> GGBuild algebra name rep a
108+ggbuild gfromColumns = case algebraSing @algebra of
109+ SProduct ->
110+ gtabulate @Id @(Eval (rep Expr)) @a $
111+ gfromColumns .
112+ gconstruct
113+ @(TTable Expr)
114+ @TColumns
115+ @Id
116+ @Expr
117+ @(Eval (rep Expr))
118+ (const toColumns)
119+ SSum ->
120+ gtabulate @Id @(GConstructorADT name (Eval (rep Expr))) @a $
121+ gfromColumns .
122+ gmakeADT
123+ @(TTable Expr)
124+ @TColumns
125+ @Id
126+ @Expr
127+ @name
128+ @(Eval (rep Expr))
129+ (const toColumns)
130+ (\Spec {info} -> snull info)
131+ (\Spec {nullity} -> case nullity of
132+ Null -> id
133+ NotNull -> nullify)
134+ (HIdentity . litExpr)
135+
136+
137+type GGConstructable :: K.Algebra -> (K.Context -> Exp (Type -> Type)) -> Constraint
138+type GGConstructable algebra rep =
139+ ( KnownAlgebra algebra
140+ , Eval (GGColumns algebra TColumns (Eval (rep Aggregate))) ~ Eval (GGColumns algebra TColumns (Eval (rep Expr)))
141+ , Eval (GGColumns algebra TColumns (Eval (rep Expr))) ~ Eval (GGColumns algebra TColumns (Eval (rep Expr)))
142+ , Eval (GGColumns algebra TColumns (Eval (rep Name))) ~ Eval (GGColumns algebra TColumns (Eval (rep Expr)))
143+ , HTable (Eval (GGColumns algebra TColumns (Eval (rep Expr))))
144+ , GGConstructable' algebra rep
145+ )
146+
147+
148+type GGConstructable' :: K.Algebra -> (K.Context -> Exp (Type -> Type)) -> Constraint
149+type family GGConstructable' algebra rep where
150+ GGConstructable' 'K.Product rep =
151+ ( Representable Id (Eval (rep Aggregate))
152+ , Representable Id (Eval (rep Expr))
153+ , Representable Id (Eval (rep Name))
154+ , GConstructable (TTable Aggregate) TColumns Id Aggregate (Eval (rep Aggregate))
155+ , GConstructable (TTable Expr) TColumns Id Expr (Eval (rep Expr))
156+ , GConstructable (TTable Name) TColumns Id Name (Eval (rep Name))
157+ )
158+ GGConstructable' 'K.Sum rep =
159+ ( RepresentableConstructors Id (Eval (rep Expr))
160+ , RepresentableFields Id (Eval (rep Aggregate))
161+ , RepresentableFields Id (Eval (rep Expr))
162+ , RepresentableFields Id (Eval (rep Name))
163+ , Functor (GConstructors Id (Eval (rep Expr)))
164+ , GConstructableADT (TTable Aggregate) TColumns Id Aggregate (Eval (rep Aggregate))
165+ , GConstructableADT (TTable Expr) TColumns Id Expr (Eval (rep Expr))
166+ , GConstructableADT (TTable Name) TColumns Id Name (Eval (rep Name))
167+ )
168+
169+
170+type GGConstruct :: K.Algebra -> (K.Context -> Exp (Type -> Type)) -> Type -> Type
171+type family GGConstruct algebra rep r where
172+ GGConstruct 'K.Product rep r = GConstruct Id (Eval (rep Expr)) r -> r
173+ GGConstruct 'K.Sum rep r = GConstructADT Id (Eval (rep Expr)) r r
174+
175+
176+ggconstruct :: forall algebra rep a. GGConstructable algebra rep
177+ => (Eval (GGColumns algebra TColumns (Eval (rep Expr))) Expr -> a)
178+ -> GGConstruct algebra rep a -> a
179+ggconstruct gfromColumns f = case algebraSing @algebra of
180+ SProduct ->
181+ f $
182+ gtabulate @Id @(Eval (rep Expr)) @a $
183+ gfromColumns .
184+ gconstruct
185+ @(TTable Expr)
186+ @TColumns
187+ @Id
188+ @Expr
189+ @(Eval (rep Expr))
190+ (const toColumns)
191+ SSum ->
192+ gcindex @Id @(Eval (rep Expr)) @a f $
193+ fmap gfromColumns $
194+ gconstructADT
195+ @(TTable Expr)
196+ @TColumns
197+ @Id
198+ @Expr
199+ @(Eval (rep Expr))
200+ (const toColumns)
201+ (\Spec {info} -> snull info)
202+ (\Spec {nullity} -> case nullity of
203+ Null -> id
204+ NotNull -> nullify)
205+ (HIdentity . litExpr)
206+
207+
208+type GGDeconstruct :: K.Algebra -> (K.Context -> Exp (Type -> Type)) -> Type -> Type -> Type
209+type family GGDeconstruct algebra rep a r where
210+ GGDeconstruct 'K.Product rep a r =
211+ GConstruct Id (Eval (rep Expr)) r -> a -> r
212+ GGDeconstruct 'K.Sum rep a r =
213+ GConstructADT Id (Eval (rep Expr)) r (a -> r)
214+
215+
216+ggdeconstruct :: forall algebra rep a r. (GGConstructable algebra rep, Table Expr r)
217+ => (a -> Eval (GGColumns algebra TColumns (Eval (rep Expr))) Expr)
218+ -> GGDeconstruct algebra rep a r
219+ggdeconstruct gtoColumns = case algebraSing @algebra of
220+ SProduct -> \build ->
221+ gindex @Id @(Eval (rep Expr)) @r build .
222+ gdeconstruct
223+ @(TTable Expr)
224+ @TColumns
225+ @Id
226+ @Expr
227+ @(Eval (rep Expr))
228+ (const fromColumns) .
229+ gtoColumns
230+ SSum ->
231+ gctabulate @Id @(Eval (rep Expr)) @r @(a -> r) $ \constructors as ->
232+ let
233+ (HIdentity tag, cases) =
234+ gdeconstructADT
235+ @(TTable Expr)
236+ @TColumns
237+ @Id
238+ @Expr
239+ @(Eval (rep Expr))
240+ (const fromColumns)
241+ (\Spec {nullity} -> case nullity of
242+ Null -> id
243+ NotNull -> unsafeUnnullify)
244+ constructors $
245+ gtoColumns as
246+ in
247+ case cases of
248+ ((_, r) :| (map (first ((tag ==.) . litExpr)) -> cases')) ->
249+ case_ cases' r
250+
251+
252+type GGName :: K.Algebra -> (K.Context -> Exp (Type -> Type)) -> Type -> Type
253+type family GGName algebra rep a where
254+ GGName 'K.Product rep a = GConstruct Id (Eval (rep Name)) a
255+ GGName 'K.Sum rep a = Name Tag -> GBuildADT Id (Eval (rep Name)) a
256+
257+
258+ggname :: forall algebra rep a. GGConstructable algebra rep
259+ => (Eval (GGColumns algebra TColumns (Eval (rep Expr))) Name -> a)
260+ -> GGName algebra rep a
261+ggname gfromColumns = case algebraSing @algebra of
262+ SProduct ->
263+ gtabulate @Id @(Eval (rep Name)) @a $
264+ gfromColumns .
265+ gconstruct
266+ @(TTable Name)
267+ @TColumns
268+ @Id
269+ @Name
270+ @(Eval (rep Name))
271+ (const toColumns)
272+ SSum -> \tag ->
273+ gftabulate @Id @(Eval (rep Name)) @a $
274+ gfromColumns .
275+ gbuildADT
276+ @(TTable Name)
277+ @TColumns
278+ @Id
279+ @Name
280+ @(Eval (rep Name))
281+ (const toColumns)
282+ (\_ _ (Name a) -> Name a)
283+ (HIdentity tag)
284+
285+
286+type GGAggregate :: K.Algebra -> (K.Context -> Exp (Type -> Type)) -> Type -> Type
287+type family GGAggregate algebra rep r where
288+ GGAggregate 'K.Product rep r =
289+ GConstruct Id (Eval (rep Aggregate)) r ->
290+ GConstruct Id (Eval (rep Expr)) r
291+ GGAggregate 'K.Sum rep r =
292+ GBuildADT Id (Eval (rep Aggregate)) r ->
293+ GBuildADT Id (Eval (rep Expr)) r
294+
295+
296+ggaggregate :: forall algebra rep exprs agg. GGConstructable algebra rep
297+ => (Eval (GGColumns algebra TColumns (Eval (rep Expr))) Aggregate -> agg)
298+ -> (exprs -> Eval (GGColumns algebra TColumns (Eval (rep Expr))) Expr)
299+ -> GGAggregate algebra rep agg -> exprs -> agg
300+ggaggregate gfromColumns gtoColumns agg es = case algebraSing @algebra of
301+ SProduct -> flip f exprs $
302+ gfromColumns .
303+ gconstruct
304+ @(TTable Aggregate)
305+ @TColumns
306+ @Id
307+ @Aggregate
308+ @(Eval (rep Aggregate))
309+ (const toColumns)
310+ where
311+ f =
312+ gindex @Id @(Eval (rep Expr)) @agg .
313+ agg .
314+ gtabulate @Id @(Eval (rep Aggregate)) @agg
315+ exprs =
316+ gdeconstruct
317+ @(TTable Expr)
318+ @TColumns
319+ @Id
320+ @Expr
321+ @(Eval (rep Expr))
322+ (const fromColumns) $
323+ gtoColumns es
324+ SSum -> flip f exprs $
325+ gfromColumns .
326+ gbuildADT
327+ @(TTable Aggregate)
328+ @TColumns
329+ @Id
330+ @Aggregate
331+ @(Eval (rep Aggregate))
332+ (const toColumns)
333+ (\tag' Spec {nullity} (Aggregate a) ->
334+ Aggregate $ sguard (tag ==. litExpr tag') . snullify nullity <$> a)
335+ (HIdentity (groupByExpr tag))
336+ where
337+ f =
338+ gfindex @Id @(Eval (rep Expr)) @agg .
339+ agg .
340+ gftabulate @Id @(Eval (rep Aggregate)) @agg
341+ (HIdentity tag, exprs) =
342+ gunbuildADT
343+ @(TTable Expr)
344+ @TColumns
345+ @Id
346+ @Expr
347+ @(Eval (rep Expr))
348+ (const fromColumns)
349+ (\Spec {nullity} -> case nullity of
350+ Null -> id
351+ NotNull -> unsafeUnnullify) $
352+ gtoColumns es
src/Rel8/Generic/Construction/ADT.hsnew file+478
@@ -0,0 +1,478 @@
1+{-# language AllowAmbiguousTypes #-}
2+{-# language BlockArguments #-}
3+{-# language DataKinds #-}
4+{-# language FlexibleContexts #-}
5+{-# language FlexibleInstances #-}
6+{-# language MultiParamTypeClasses #-}
7+{-# language RankNTypes #-}
8+{-# language ScopedTypeVariables #-}
9+{-# language StandaloneKindSignatures #-}
10+{-# language TupleSections #-}
11+{-# language TypeApplications #-}
12+{-# language TypeFamilies #-}
13+{-# language TypeOperators #-}
14+{-# language UndecidableInstances #-}
15+
16+module Rel8.Generic.Construction.ADT
17+ ( GConstructableADT
18+ , GBuildADT, gbuildADT, gunbuildADT
19+ , GConstructADT, gconstructADT, gdeconstructADT
20+ , GFields, RepresentableFields, gftabulate, gfindex
21+ , GConstructors, RepresentableConstructors, gctabulate, gcindex
22+ , GConstructorADT, GMakeableADT, gmakeADT
23+ )
24+where
25+
26+-- base
27+import Data.Bifunctor ( first )
28+import Data.Functor.Identity ( runIdentity )
29+import Data.Kind ( Constraint, Type )
30+import Data.List.NonEmpty ( NonEmpty )
31+import Data.Proxy ( Proxy( Proxy ) )
32+import GHC.Generics
33+ ( (:+:), (:*:)( (:*:) ), M1, U1
34+ , C, D
35+ , Meta( MetaData, MetaCons )
36+ )
37+import GHC.TypeLits
38+ ( ErrorMessage( (:<>:), Text ), TypeError
39+ , Symbol, KnownSymbol, symbolVal
40+ )
41+import Prelude hiding ( null )
42+
43+-- rel8
44+import Rel8.FCF ( Exp )
45+import Rel8.Generic.Construction.Record
46+ ( GConstruct, GConstructable, gconstruct, gdeconstruct
47+ , GFields, Representable, gtabulate, gindex
48+ , FromColumns, ToColumns
49+ )
50+import Rel8.Generic.Table.ADT ( GColumnsADT, GColumnsADT' )
51+import Rel8.Generic.Table.Record ( GColumns )
52+import Rel8.Schema.HTable ( HTable )
53+import Rel8.Schema.HTable.Identity ( HIdentity )
54+import Rel8.Schema.HTable.Label ( HLabel, hlabel, hunlabel )
55+import Rel8.Schema.HTable.Nullify ( HNullify, hnulls, hnullify, hunnullify )
56+import Rel8.Schema.HTable.Product ( HProduct( HProduct ) )
57+import Rel8.Schema.Null ( Nullify )
58+import Rel8.Schema.Spec ( Spec )
59+import qualified Rel8.Schema.Kind as K
60+import Rel8.Type.Tag ( Tag( Tag ) )
61+
62+-- text
63+import Data.Text ( pack )
64+
65+
66+type Null :: K.Context -> Type
67+type Null context = forall a. Spec a -> context (Nullify a)
68+
69+
70+type Nullifier :: K.Context -> Type
71+type Nullifier context = forall a. Spec a -> context a -> context (Nullify a)
72+
73+
74+type Unnullifier :: K.Context -> Type
75+type Unnullifier context = forall a. Spec a -> context (Nullify a) -> context a
76+
77+
78+type NoConstructor :: Symbol -> Symbol -> ErrorMessage
79+type NoConstructor datatype constructor =
80+ ( 'Text "The type `" ':<>:
81+ 'Text datatype ':<>:
82+ 'Text "` has no constructor `" ':<>:
83+ 'Text constructor ':<>:
84+ 'Text "`."
85+ )
86+
87+
88+type GConstructorADT :: Symbol -> (Type -> Type) -> Type -> Type
89+type family GConstructorADT name rep where
90+ GConstructorADT name (M1 D ('MetaData datatype _ _ _) rep) =
91+ GConstructorADT' name rep (TypeError (NoConstructor datatype name))
92+
93+
94+type GConstructorADT' :: Symbol -> (Type -> Type) -> (Type -> Type) -> Type -> Type
95+type family GConstructorADT' name rep fallback where
96+ GConstructorADT' name (M1 D _ rep) fallback =
97+ GConstructorADT' name rep fallback
98+ GConstructorADT' name (a :+: b) fallback =
99+ GConstructorADT' name a (GConstructorADT' name b fallback)
100+ GConstructorADT' name (M1 C ('MetaCons name _ _) rep) _ = rep
101+ GConstructorADT' _ _ fallback = fallback
102+
103+
104+type GConstructADT
105+ :: (Type -> Exp Type)
106+ -> (Type -> Type) -> Type -> Type -> Type
107+type family GConstructADT f rep r x where
108+ GConstructADT f (M1 D _ rep) r x = GConstructADT f rep r x
109+ GConstructADT f (a :+: b) r x = GConstructADT f a r (GConstructADT f b r x)
110+ GConstructADT f (M1 C _ rep) r x = GConstruct f rep r -> x
111+
112+
113+type GConstructors :: (Type -> Exp Type) -> (Type -> Type) -> Type -> Type
114+type family GConstructors f rep where
115+ GConstructors f (M1 D _ rep) = GConstructors f rep
116+ GConstructors f (a :+: b) = GConstructors f a :*: GConstructors f b
117+ GConstructors f (M1 C _ rep) = (->) (GFields f rep)
118+
119+
120+type RepresentableConstructors :: (Type -> Exp Type) -> (Type -> Type) -> Constraint
121+class RepresentableConstructors f rep where
122+ gctabulate :: (GConstructors f rep r -> a) -> GConstructADT f rep r a
123+ gcindex :: GConstructADT f rep r a -> GConstructors f rep r -> a
124+
125+
126+instance RepresentableConstructors f rep => RepresentableConstructors f (M1 D meta rep) where
127+ gctabulate = gctabulate @f @rep
128+ gcindex = gcindex @f @rep
129+
130+
131+instance (RepresentableConstructors f a, RepresentableConstructors f b) =>
132+ RepresentableConstructors f (a :+: b)
133+ where
134+ gctabulate f =
135+ gctabulate @f @a \a -> gctabulate @f @b \b -> f (a :*: b)
136+ gcindex f (a :*: b) = gcindex @f @b (gcindex @f @a f a) b
137+
138+
139+instance Representable f rep => RepresentableConstructors f (M1 C meta rep) where
140+ gctabulate f = f . gindex @f @rep
141+ gcindex f = f . gtabulate @f @rep
142+
143+
144+type GBuildADT :: (Type -> Exp Type) -> (Type -> Type) -> Type -> Type
145+type family GBuildADT f rep r where
146+ GBuildADT f (M1 D _ rep) r = GBuildADT f rep r
147+ GBuildADT f (a :+: b) r = GBuildADT f a (GBuildADT f b r)
148+ GBuildADT f (M1 C _ rep) r = GConstruct f rep r
149+
150+
151+type GFieldsADT :: (Type -> Exp Type) -> (Type -> Type) -> Type
152+type family GFieldsADT f rep where
153+ GFieldsADT f (M1 D _ rep) = GFieldsADT f rep
154+ GFieldsADT f (a :+: b) = (GFieldsADT f a, GFieldsADT f b)
155+ GFieldsADT f (M1 C _ rep) = GFields f rep
156+
157+
158+type RepresentableFields :: (Type -> Exp Type) -> (Type -> Type) -> Constraint
159+class RepresentableFields f rep where
160+ gftabulate :: (GFieldsADT f rep -> a) -> GBuildADT f rep a
161+ gfindex :: GBuildADT f rep a -> GFieldsADT f rep -> a
162+
163+
164+instance RepresentableFields f rep => RepresentableFields f (M1 D meta rep) where
165+ gftabulate = gftabulate @f @rep
166+ gfindex = gfindex @f @rep
167+
168+
169+instance (RepresentableFields f a, RepresentableFields f b) => RepresentableFields f (a :+: b) where
170+ gftabulate f =
171+ gftabulate @f @a \a -> gftabulate @f @b \b -> f (a, b)
172+ gfindex f (a, b) = gfindex @f @b (gfindex @f @a f a) b
173+
174+
175+instance Representable f rep => RepresentableFields f (M1 C meta rep) where
176+ gftabulate = gtabulate @f @rep
177+ gfindex = gindex @f @rep
178+
179+
180+type GConstructableADT
181+ :: (Type -> Exp Constraint)
182+ -> (Type -> Exp K.HTable)
183+ -> (Type -> Exp Type)
184+ -> K.Context -> (Type -> Type) -> Constraint
185+class GConstructableADT _Table _Columns f context rep where
186+ gbuildADT :: ()
187+ => ToColumns _Table _Columns f context
188+ -> (Tag -> Nullifier context)
189+ -> HIdentity Tag context
190+ -> GFieldsADT f rep
191+ -> GColumnsADT _Columns rep context
192+
193+ gunbuildADT :: ()
194+ => FromColumns _Table _Columns f context
195+ -> Unnullifier context
196+ -> GColumnsADT _Columns rep context
197+ -> (HIdentity Tag context, GFieldsADT f rep)
198+
199+ gconstructADT :: ()
200+ => ToColumns _Table _Columns f context
201+ -> Null context
202+ -> Nullifier context
203+ -> (Tag -> HIdentity Tag context)
204+ -> GConstructors f rep (GColumnsADT _Columns rep context)
205+
206+ gdeconstructADT :: ()
207+ => FromColumns _Table _Columns f context
208+ -> Unnullifier context
209+ -> GConstructors f rep r
210+ -> GColumnsADT _Columns rep context
211+ -> (HIdentity Tag context, NonEmpty (Tag, r))
212+
213+
214+instance
215+ ( htable ~ HLabel "tag" (HIdentity Tag)
216+ , GConstructableADT' _Table _Columns f context htable rep
217+ )
218+ => GConstructableADT _Table _Columns f context (M1 D meta rep)
219+ where
220+ gbuildADT toColumns nullifier =
221+ gbuildADT' @_Table @_Columns @f @context @htable @rep toColumns nullifier .
222+ hlabel
223+
224+ gunbuildADT fromColumns unnullifier =
225+ first hunlabel .
226+ gunbuildADT' @_Table @_Columns @f @context @htable @rep fromColumns unnullifier
227+
228+ gconstructADT toColumns null nullifier mk =
229+ gconstructADT' @_Table @_Columns @f @context @htable @rep toColumns null nullifier
230+ (hlabel . mk)
231+
232+ gdeconstructADT fromColumns unnullifier cases =
233+ first hunlabel .
234+ gdeconstructADT' @_Table @_Columns @f @context @htable @rep fromColumns unnullifier cases
235+
236+
237+type GConstructableADT'
238+ :: (Type -> Exp Constraint)
239+ -> (Type -> Exp K.HTable)
240+ -> (Type -> Exp Type)
241+ -> K.Context -> K.HTable -> (Type -> Type) -> Constraint
242+class GConstructableADT' _Table _Columns f context htable rep where
243+ gbuildADT' :: ()
244+ => ToColumns _Table _Columns f context
245+ -> (Tag -> Nullifier context)
246+ -> htable context
247+ -> GFieldsADT f rep
248+ -> GColumnsADT' _Columns htable rep context
249+
250+ gunbuildADT' :: ()
251+ => FromColumns _Table _Columns f context
252+ -> Unnullifier context
253+ -> GColumnsADT' _Columns htable rep context
254+ -> (htable context, GFieldsADT f rep)
255+
256+ gconstructADT' :: ()
257+ => ToColumns _Table _Columns f context
258+ -> Null context
259+ -> Nullifier context
260+ -> (Tag -> htable context)
261+ -> GConstructors f rep (GColumnsADT' _Columns htable rep context)
262+
263+ gdeconstructADT' :: ()
264+ => FromColumns _Table _Columns f context
265+ -> Unnullifier context
266+ -> GConstructors f rep r
267+ -> GColumnsADT' _Columns htable rep context
268+ -> (htable context, NonEmpty (Tag, r))
269+
270+ gfill :: ()
271+ => Null context
272+ -> htable context
273+ -> GColumnsADT' _Columns htable rep context
274+
275+
276+instance
277+ ( htable' ~ GColumnsADT' _Columns htable a
278+ , Functor (GConstructors f a)
279+ , GConstructableADT' _Table _Columns f context htable a
280+ , GConstructableADT' _Table _Columns f context htable' b
281+ )
282+ => GConstructableADT' _Table _Columns f context htable (a :+: b)
283+ where
284+ gbuildADT' toColumns nullifier htable (a, b) =
285+ gbuildADT' @_Table @_Columns @f @context @htable' @b toColumns nullifier
286+ (gbuildADT' @_Table @_Columns @f @context @htable @a toColumns nullifier htable a)
287+ b
288+
289+ gunbuildADT' fromColumns unnullifier columns =
290+ case gunbuildADT' @_Table @_Columns @f @context @htable' @b fromColumns unnullifier columns of
291+ (htable', b) ->
292+ case gunbuildADT' @_Table @_Columns @f @context @htable @a fromColumns unnullifier htable' of
293+ (htable, a) -> (htable, (a, b))
294+
295+ gconstructADT' toColumns null nullifier mk =
296+ fmap (gfill @_Table @_Columns @f @context @htable' @b null) (gconstructADT' @_Table @_Columns @f @context @htable @a toColumns null nullifier mk) :*:
297+ gconstructADT' @_Table @_Columns @f @context @htable' @b toColumns null nullifier (gfill @_Table @_Columns @f @context @htable @a null . mk)
298+
299+ gdeconstructADT' fromColumns unnullifier (a :*: b) columns =
300+ case gdeconstructADT' @_Table @_Columns @f @context @htable' @b fromColumns unnullifier b columns of
301+ (htable', cases) ->
302+ case gdeconstructADT' @_Table @_Columns @f @context @htable @a fromColumns unnullifier a htable' of
303+ (htable, cases') -> (htable, cases' <> cases)
304+
305+ gfill null =
306+ gfill @_Table @_Columns @f @context @htable' @b null .
307+ gfill @_Table @_Columns @f @context @htable @a null
308+
309+
310+instance (meta ~ 'MetaCons label _fixity _isRecord, KnownSymbol label) =>
311+ GConstructableADT' _Table _Columns f context htable (M1 C meta U1)
312+ where
313+ gbuildADT' _ _ = const
314+ gunbuildADT' _ _ = (, ())
315+ gconstructADT' _ _ _ f _ = f tag
316+ where
317+ tag = Tag $ pack $ symbolVal (Proxy @label)
318+ gdeconstructADT' _ _ r htable = (htable, pure (tag, r ()))
319+ where
320+ tag = Tag $ pack $ symbolVal (Proxy @label)
321+ gfill _ = id
322+
323+
324+instance {-# OVERLAPPABLE #-}
325+ ( HTable (GColumns _Columns rep)
326+ , KnownSymbol label
327+ , meta ~ 'MetaCons label _fixity _isRecord
328+ , GConstructable _Table _Columns f context rep
329+ , GColumnsADT' _Columns htable (M1 C meta rep) ~
330+ HProduct htable (HLabel label (HNullify (GColumns _Columns rep)))
331+ )
332+ => GConstructableADT' _Table _Columns f context htable (M1 C meta rep)
333+ where
334+ gbuildADT' toColumns nullifier htable =
335+ HProduct htable .
336+ hlabel .
337+ hnullify (nullifier tag) .
338+ gconstruct @_Table @_Columns @f @context @rep toColumns
339+ where
340+ tag = Tag $ pack $ symbolVal (Proxy @label)
341+
342+ gunbuildADT' fromColumns unnullifier (HProduct htable a) =
343+ ( htable
344+ , gdeconstruct @_Table @_Columns @f @context @rep fromColumns $
345+ runIdentity $
346+ hunnullify (\spec -> pure . unnullifier spec) $
347+ hunlabel
348+ a
349+ )
350+
351+ gconstructADT' toColumns _ nullifier mk =
352+ HProduct htable .
353+ hlabel .
354+ hnullify nullifier .
355+ gconstruct @_Table @_Columns @f @context @rep toColumns
356+ where
357+ tag = Tag $ pack $ symbolVal (Proxy @label)
358+ htable = mk tag
359+
360+ gdeconstructADT' fromColumns unnullifier r (HProduct htable columns) =
361+ ( htable
362+ , pure (tag, r a)
363+ )
364+ where
365+ a = gdeconstruct @_Table @_Columns @f @context @rep fromColumns $
366+ runIdentity $
367+ hunnullify (\spec -> pure . unnullifier spec) $
368+ hunlabel
369+ columns
370+ tag = Tag $ pack $ symbolVal (Proxy @label)
371+
372+ gfill null htable = HProduct htable (hlabel (hnulls null))
373+
374+
375+type GMakeableADT
376+ :: (Type -> Exp Constraint)
377+ -> (Type -> Exp K.HTable)
378+ -> (Type -> Exp Type)
379+ -> K.Context -> Symbol -> (Type -> Type) -> Constraint
380+class GMakeableADT _Table _Columns f context name rep where
381+ gmakeADT :: ()
382+ => ToColumns _Table _Columns f context
383+ -> Null context
384+ -> Nullifier context
385+ -> (Tag -> HIdentity Tag context)
386+ -> GFields f (GConstructorADT name rep)
387+ -> GColumnsADT _Columns rep context
388+
389+
390+instance
391+ ( htable ~ HLabel "tag" (HIdentity Tag)
392+ , meta ~ 'MetaData datatype _module _package _newtype
393+ , fallback ~ TypeError (NoConstructor datatype name)
394+ , fields ~ GFields f (GConstructorADT' name rep fallback)
395+ , GMakeableADT' _Table _Columns f context htable name rep fields
396+ , KnownSymbol name
397+ )
398+ => GMakeableADT _Table _Columns f context name (M1 D meta rep)
399+ where
400+ gmakeADT toColumns null nullifier wrap =
401+ gmakeADT'
402+ @_Table @_Columns @f @context @htable @name @rep @fields
403+ toColumns null nullifier htable
404+ where
405+ tag = Tag $ pack $ symbolVal (Proxy @name)
406+ htable = hlabel (wrap tag)
407+
408+
409+type GMakeableADT'
410+ :: (Type -> Exp Constraint)
411+ -> (Type -> Exp K.HTable)
412+ -> (Type -> Exp Type)
413+ -> K.Context -> K.HTable -> Symbol -> (Type -> Type) -> Type -> Constraint
414+class GMakeableADT' _Table _Columns f context htable name rep fields where
415+ gmakeADT' :: ()
416+ => ToColumns _Table _Columns f context
417+ -> Null context
418+ -> Nullifier context
419+ -> htable context
420+ -> fields
421+ -> GColumnsADT' _Columns htable rep context
422+
423+
424+instance
425+ ( htable' ~ GColumnsADT' _Columns htable a
426+ , GMakeableADT' _Table _Columns f context htable name a fields
427+ , GMakeableADT' _Table _Columns f context htable' name b fields
428+ )
429+ => GMakeableADT' _Table _Columns f context htable name (a :+: b) fields
430+ where
431+ gmakeADT' toColumns null nullifier htable x =
432+ gmakeADT' @_Table @_Columns @f @context @htable' @name @b @fields
433+ toColumns null nullifier
434+ (gmakeADT'
435+ @_Table @_Columns @f @context @htable @name @a @fields toColumns
436+ null nullifier htable x)
437+ x
438+
439+
440+instance {-# OVERLAPPING #-}
441+ GMakeableADT' _Table _Columns f context htable name (M1 C ('MetaCons name _fixity _isRecord) U1) fields
442+ where
443+ gmakeADT' _ _ _ = const
444+
445+
446+instance {-# OVERLAPS #-}
447+ GMakeableADT' _Table _Columns f context htable name (M1 C ('MetaCons label _fixity _isRecord) U1) fields
448+ where
449+ gmakeADT' _ _ _ = const
450+
451+
452+instance {-# OVERLAPS #-}
453+ ( HTable (GColumns _Columns rep)
454+ , GConstructable _Table _Columns f context rep
455+ , fields ~ GFields f rep
456+ , GColumnsADT' _Columns htable (M1 C ('MetaCons name _fixity _isRecord) rep) ~
457+ HProduct htable (HLabel name (HNullify (GColumns _Columns rep)))
458+ )
459+ => GMakeableADT' _Table _Columns f context htable name (M1 C ('MetaCons name _fixity _isRecord) rep) fields
460+ where
461+ gmakeADT' toColumns _ nullifier htable =
462+ HProduct htable .
463+ hlabel .
464+ hnullify nullifier .
465+ gconstruct @_Table @_Columns @f @context @rep toColumns
466+
467+
468+instance {-# OVERLAPPABLE #-}
469+ ( HTable (GColumns _Columns rep)
470+ , GColumnsADT' _Columns htable (M1 C ('MetaCons label _fixity _isRecord) rep) ~
471+ HProduct htable (HLabel label (HNullify (GColumns _Columns rep)))
472+ )
473+ => GMakeableADT' _Table _Columns f context htable name (M1 C ('MetaCons label _fixity _isRecord) rep) fields
474+ where
475+ gmakeADT' _ null _ htable _ =
476+ HProduct htable $
477+ hlabel $
478+ hnulls null
src/Rel8/Generic/Construction/Record.hsnew file+168
@@ -0,0 +1,168 @@
1+{-# language AllowAmbiguousTypes #-}
2+{-# language BlockArguments #-}
3+{-# language DataKinds #-}
4+{-# language FlexibleInstances #-}
5+{-# language MultiParamTypeClasses #-}
6+{-# language RankNTypes #-}
7+{-# language ScopedTypeVariables #-}
8+{-# language StandaloneKindSignatures #-}
9+{-# language TypeApplications #-}
10+{-# language TypeFamilies #-}
11+{-# language TypeOperators #-}
12+{-# language UndecidableInstances #-}
13+
14+module Rel8.Generic.Construction.Record
15+ ( GConstructor, GConstruct, GConstructable, gconstruct, gdeconstruct
16+ , GFields, Representable, gtabulate, gindex
17+ , FromColumns, ToColumns
18+ )
19+where
20+
21+-- base
22+import Data.Kind ( Constraint, Type )
23+import Data.Proxy ( Proxy( Proxy ) )
24+import GHC.Generics
25+ ( (:*:), K1, M1, U1
26+ , D, C, S, Meta( MetaData, MetaCons, MetaSel )
27+ )
28+import GHC.TypeLits
29+ ( ErrorMessage( (:<>:), Text ), TypeError
30+ , Symbol
31+ )
32+import Prelude
33+
34+-- rel8
35+import Rel8.FCF ( Eval, Exp )
36+import Rel8.Generic.Table.Record ( GColumns )
37+import Rel8.Schema.HTable.Label ( hlabel, hunlabel )
38+import Rel8.Schema.HTable.Product ( HProduct( HProduct ) )
39+import qualified Rel8.Schema.Kind as K
40+
41+
42+type FromColumns
43+ :: (Type -> Exp Constraint)
44+ -> (Type -> Exp K.HTable)
45+ -> (Type -> Exp Type)
46+ -> K.Context
47+ -> Type
48+type FromColumns _Table _Columns f context = forall proxy x.
49+ Eval (_Table x) => proxy x -> Eval (_Columns x) context -> Eval (f x)
50+
51+
52+type ToColumns
53+ :: (Type -> Exp Constraint)
54+ -> (Type -> Exp K.HTable)
55+ -> (Type -> Exp Type)
56+ -> K.Context
57+ -> Type
58+type ToColumns _Table _Columns f context = forall proxy x.
59+ Eval (_Table x) => proxy x -> Eval (f x) -> Eval (_Columns x) context
60+
61+
62+type GConstructor :: (Type -> Type) -> Symbol
63+type family GConstructor rep where
64+ GConstructor (M1 D _ (M1 C ('MetaCons name _ _) _)) = name
65+ GConstructor (M1 D ('MetaData name _ _ _) _) = TypeError (
66+ 'Text "`" ':<>:
67+ 'Text name ':<>:
68+ 'Text "` does not appear to have exactly 1 constructor"
69+ )
70+
71+
72+type GConstruct :: (Type -> Exp Type) -> (Type -> Type) -> Type -> Type
73+type family GConstruct f rep r where
74+ GConstruct f (M1 _ _ rep) r = GConstruct f rep r
75+ GConstruct f (a :*: b) r = GConstruct f a (GConstruct f b r)
76+ GConstruct _ U1 r = r
77+ GConstruct f (K1 _ a) r = Eval (f a) -> r
78+
79+
80+type GFields :: (Type -> Exp Type) -> (Type -> Type) -> Type
81+type family GFields f rep where
82+ GFields f (M1 _ _ rep) = GFields f rep
83+ GFields f (a :*: b) = (GFields f a, GFields f b)
84+ GFields _ U1 = ()
85+ GFields f (K1 _ a) = Eval (f a)
86+
87+
88+type Representable :: (Type -> Exp Type) -> (Type -> Type) -> Constraint
89+class Representable f rep where
90+ gtabulate :: (GFields f rep -> a) -> GConstruct f rep a
91+ gindex :: GConstruct f rep a -> GFields f rep -> a
92+
93+
94+instance Representable f rep => Representable f (M1 i meta rep) where
95+ gtabulate = gtabulate @f @rep
96+ gindex = gindex @f @rep
97+
98+
99+instance (Representable f a, Representable f b) =>
100+ Representable f (a :*: b)
101+ where
102+ gtabulate f = gtabulate @f @a \a -> gtabulate @f @b \b -> f (a, b)
103+ gindex f (a, b) = gindex @f @b (gindex @f @a f a) b
104+
105+
106+instance Representable f U1 where
107+ gtabulate = ($ ())
108+ gindex = const
109+
110+
111+instance Representable f (K1 i a) where
112+ gtabulate = id
113+ gindex = id
114+
115+
116+type GConstructable
117+ :: (Type -> Exp Constraint)
118+ -> (Type -> Exp K.HTable)
119+ -> (Type -> Exp Type)
120+ -> K.Context -> (Type -> Type) -> Constraint
121+class GConstructable _Table _Columns f context rep where
122+ gconstruct :: ()
123+ => ToColumns _Table _Columns f context
124+ -> GFields f rep
125+ -> GColumns _Columns rep context
126+ gdeconstruct :: ()
127+ => FromColumns _Table _Columns f context
128+ -> GColumns _Columns rep context
129+ -> GFields f rep
130+
131+
132+instance (GConstructable _Table _Columns f context rep) =>
133+ GConstructable _Table _Columns f context (M1 D meta rep)
134+ where
135+ gconstruct = gconstruct @_Table @_Columns @f @context @rep
136+ gdeconstruct = gdeconstruct @_Table @_Columns @f @context @rep
137+
138+
139+instance (GConstructable _Table _Columns f context rep) =>
140+ GConstructable _Table _Columns f context (M1 C meta rep)
141+ where
142+ gconstruct = gconstruct @_Table @_Columns @f @context @rep
143+ gdeconstruct = gdeconstruct @_Table @_Columns @f @context @rep
144+
145+
146+instance
147+ ( GConstructable _Table _Columns f context a
148+ , GConstructable _Table _Columns f context b
149+ )
150+ => GConstructable _Table _Columns f context (a :*: b)
151+ where
152+ gconstruct toColumns (a, b) = HProduct
153+ (gconstruct @_Table @_Columns @f @context @a toColumns a)
154+ (gconstruct @_Table @_Columns @f @context @b toColumns b)
155+ gdeconstruct fromColumns (HProduct a b) =
156+ ( gdeconstruct @_Table @_Columns @f @context @a fromColumns a
157+ , gdeconstruct @_Table @_Columns @f @context @b fromColumns b
158+ )
159+
160+
161+instance
162+ ( Eval (_Table a)
163+ , meta ~ 'MetaSel ('Just label) _su _ss _ds
164+ )
165+ => GConstructable _Table _Columns f context (M1 S meta (K1 i a))
166+ where
167+ gconstruct toColumns = hlabel . toColumns (Proxy @a)
168+ gdeconstruct fromColumns = fromColumns (Proxy @a) . hunlabel
src/Rel8/Generic/Map.hsnew file+49
@@ -0,0 +1,49 @@
1+{-# language DataKinds #-}
2+{-# language StandaloneKindSignatures #-}
3+{-# language TypeFamilies #-}
4+{-# language TypeOperators #-}
5+{-# language UndecidableInstances #-}
6+
7+module Rel8.Generic.Map
8+ ( GMap
9+ , Map
10+ )
11+where
12+
13+-- base
14+import Data.Kind ( Type )
15+import GHC.Generics
16+ ( (:+:), (:*:), K1, M1, U1, V1
17+ )
18+import Prelude ()
19+
20+-- rel8
21+import Rel8.FCF ( Eval, Exp )
22+
23+
24+type GMap :: (Type -> Exp Type) -> (Type -> Type) -> Type -> Type
25+type family GMap f rep where
26+ GMap f (M1 i c rep) = M1 i c (GMap f rep)
27+ GMap _ V1 = V1
28+ GMap f (rep1 :+: rep2) = GMap f rep1 :+: GMap f rep2
29+ GMap _ U1 = U1
30+ GMap f (rep1 :*: rep2) = GMap f rep1 :*: GMap f rep2
31+ GMap f (K1 i a) = K1 i (Eval (f a))
32+
33+
34+-- | Map a @Type -> Type@ function over the @Type@-kinded type variables in
35+-- of a type constructor.
36+type Map :: (Type -> Exp Type) -> Type -> Type
37+type family Map f a where
38+ Map p (t a b c d e f g) =
39+ t (Eval (p a)) (Eval (p b)) (Eval (p c)) (Eval (p d)) (Eval (p e))
40+ (Eval (p f)) (Eval (p g))
41+ Map p (t a b c d e f) =
42+ t (Eval (p a)) (Eval (p b)) (Eval (p c)) (Eval (p d)) (Eval (p e))
43+ (Eval (p f))
44+ Map p (t a b c d e) =
45+ t (Eval (p a)) (Eval (p b)) (Eval (p c)) (Eval (p d)) (Eval (p e))
46+ Map p (t a b c d) = t (Eval (p a)) (Eval (p b)) (Eval (p c)) (Eval (p d))
47+ Map p (t a b c) = t (Eval (p a)) (Eval (p b)) (Eval (p c))
48+ Map p (t a b) = t (Eval (p a)) (Eval (p b))
49+ Map p (t a) = t (Eval (p a))
src/Rel8/Generic/Record.hsnew file+155
@@ -0,0 +1,155 @@
1+{-# language AllowAmbiguousTypes #-}
2+{-# language DataKinds #-}
3+{-# language FlexibleContexts #-}
4+{-# language FlexibleInstances #-}
5+{-# language MultiParamTypeClasses #-}
6+{-# language PolyKinds #-}
7+{-# language ScopedTypeVariables #-}
8+{-# language StandaloneKindSignatures #-}
9+{-# language TypeApplications #-}
10+{-# language TypeFamilies #-}
11+{-# language TypeOperators #-}
12+{-# language UndecidableInstances #-}
13+
14+module Rel8.Generic.Record
15+ ( Record(..)
16+ , GRecordable, GRecord, grecord, gunrecord
17+ )
18+where
19+
20+-- base
21+import Data.Kind ( Constraint, Type )
22+import GHC.Generics
23+ ( Generic, Rep, from, to
24+ , (:+:)( L1, R1 ), (:*:)( (:*:) ), M1( M1 )
25+ , Meta( MetaCons, MetaSel ), D, C, S
26+ )
27+import GHC.TypeLits ( type (+), AppendSymbol, Div, Mod, Nat, Symbol )
28+import Prelude hiding ( Show )
29+
30+
31+type GRecord :: (Type -> Type) -> Type -> Type
32+type family GRecord rep where
33+ GRecord (M1 D meta rep) = M1 D meta (GRecord rep)
34+ GRecord (l :+: r) = GRecord l :+: GRecord r
35+ GRecord (M1 C ('MetaCons name fixity 'False) rep) =
36+ M1 C ('MetaCons name fixity 'True) (Snd (Count 0 rep))
37+ GRecord rep = rep
38+
39+
40+type Count :: Nat -> (Type -> Type) -> (Nat, Type -> Type)
41+type family Count n rep where
42+ Count n (M1 S ('MetaSel _selector su ss ds) rep) =
43+ '(n + 1, M1 S ('MetaSel ('Just (Show (n + 1))) su ss ds) rep)
44+ Count n (a :*: b) = CountHelper1 (Count n a) b
45+ Count n rep = '(n, rep)
46+
47+
48+type CountHelper1 :: (Nat, Type -> Type) -> (Type -> Type) -> (Nat, Type -> Type)
49+type family CountHelper1 tuple b where
50+ CountHelper1 '(n, a) b = CountHelper2 a (Count n b)
51+
52+
53+type CountHelper2 :: (Type -> Type) -> (Nat, Type -> Type) -> (Nat, Type -> Type)
54+type family CountHelper2 a tuple where
55+ CountHelper2 a '(n, b) = '(n, a :*: b)
56+
57+
58+type Show :: Nat -> Symbol
59+type Show n =
60+ AppendSymbol "_" (AppendSymbol (Show' (Div n 10)) (ShowDigit (Mod n 10)))
61+
62+
63+type Show' :: Nat -> Symbol
64+type family Show' n where
65+ Show' 0 = ""
66+ Show' n = AppendSymbol (Show' (Div n 10)) (ShowDigit (Mod n 10))
67+
68+
69+type ShowDigit :: Nat -> Symbol
70+type family ShowDigit n where
71+ ShowDigit 0 = "0"
72+ ShowDigit 1 = "1"
73+ ShowDigit 2 = "2"
74+ ShowDigit 3 = "3"
75+ ShowDigit 4 = "4"
76+ ShowDigit 5 = "5"
77+ ShowDigit 6 = "6"
78+ ShowDigit 7 = "7"
79+ ShowDigit 8 = "8"
80+ ShowDigit 9 = "9"
81+
82+
83+type Snd :: (a, b) -> b
84+type family Snd tuple where
85+ Snd '(_a, b) = b
86+
87+
88+type GRecordable :: (Type -> Type) -> Constraint
89+class GRecordable rep where
90+ grecord :: rep x -> GRecord rep x
91+ gunrecord :: GRecord rep x -> rep x
92+
93+
94+instance GRecordable rep => GRecordable (M1 D meta rep) where
95+ grecord (M1 a) = M1 (grecord a)
96+ gunrecord (M1 a) = M1 (gunrecord a)
97+
98+
99+instance (GRecordable l, GRecordable r) => GRecordable (l :+: r) where
100+ grecord (L1 a) = L1 (grecord a)
101+ grecord (R1 a) = R1 (grecord a)
102+ gunrecord (L1 a) = L1 (gunrecord a)
103+ gunrecord (R1 a) = R1 (gunrecord a)
104+
105+
106+instance Countable 0 rep =>
107+ GRecordable (M1 C ('MetaCons name fixity 'False) rep)
108+ where
109+ grecord (M1 a) = M1 (count @0 a)
110+ gunrecord (M1 a) = M1 (uncount @0 a)
111+
112+
113+instance {-# OVERLAPPABLE #-} GRecord rep ~ rep => GRecordable rep where
114+ grecord = id
115+ gunrecord = id
116+
117+
118+type Countable :: Nat -> (Type -> Type) -> Constraint
119+class Countable n rep where
120+ count :: rep x -> Snd (Count n rep) x
121+ uncount :: Snd (Count n rep) x -> rep x
122+
123+
124+instance Countable n (M1 S ('MetaSel selector su ss ds) rep) where
125+ count (M1 a) = M1 a
126+ uncount (M1 a) = M1 a
127+
128+
129+instance
130+ ( Countable n a, Countable n' b
131+ , '(n', a') ~ Count n a
132+ , Snd (CountHelper2 a' (Count n' b)) ~ (a' :*: Snd (Count n' b))
133+ )
134+ => Countable n (a :*: b)
135+ where
136+ count (a :*: b) = count @n a :*: count @n' b
137+ uncount (a :*: b) = uncount @n a :*: uncount @n' b
138+
139+
140+instance {-# OVERLAPPABLE #-} Snd (Count n rep) ~ rep => Countable n rep where
141+ count = id
142+ uncount = id
143+
144+
145+type Record :: Type -> Type
146+newtype Record a = Record
147+ { unrecord :: a
148+ }
149+
150+
151+instance (Generic a, GRecordable (Rep a)) => Generic (Record a) where
152+ type Rep (Record a) = GRecord (Rep a)
153+
154+ from (Record a) = grecord (from a)
155+ to = Record . to . gunrecord
src/Rel8/Generic/Rel8able.hsnew file+281
@@ -0,0 +1,281 @@
1+{-# language AllowAmbiguousTypes #-}
2+{-# language ConstraintKinds #-}
3+{-# language DataKinds #-}
4+{-# language DefaultSignatures #-}
5+{-# language FlexibleContexts #-}
6+{-# language FlexibleInstances #-}
7+{-# language LambdaCase #-}
8+{-# language MultiParamTypeClasses #-}
9+{-# language PolyKinds #-}
10+{-# language QuantifiedConstraints #-}
11+{-# language ScopedTypeVariables #-}
12+{-# language StandaloneKindSignatures #-}
13+{-# language TypeApplications #-}
14+{-# language TypeFamilyDependencies #-}
15+{-# language TypeOperators #-}
16+{-# language UndecidableInstances #-}
17+
18+module Rel8.Generic.Rel8able
19+ ( KRel8able, Rel8able
20+ , Algebra
21+ , GRep
22+ , GColumns, gfromColumns, gtoColumns
23+ , GFromExprs, gfromResult, gtoResult
24+ , TSerialize, serialize, deserialize
25+ )
26+where
27+
28+-- base
29+import Data.Functor.Identity ( Identity )
30+import Data.Kind ( Constraint, Type )
31+import Data.Type.Bool ( type (&&) )
32+import GHC.Generics ( Generic, Rep, from, to )
33+import Prelude
34+
35+-- rel8
36+import Rel8.Aggregate ( Aggregate )
37+import Rel8.Expr ( Expr )
38+import Rel8.FCF ( Exp, Eval )
39+import Rel8.Generic.Record ( Record(..) )
40+import Rel8.Generic.Table ( GAlgebra )
41+import qualified Rel8.Generic.Table.Record as G
42+import qualified Rel8.Kind.Algebra as K ( Algebra(..) )
43+import Rel8.Kind.Context ( SContext(..) )
44+import Rel8.Schema.Field ( Field )
45+import Rel8.Schema.HTable ( HTable )
46+import qualified Rel8.Schema.Kind as K
47+import Rel8.Schema.Name ( Name )
48+import Rel8.Schema.Result ( Result )
49+import Rel8.Table
50+ ( Table, Columns, Context, fromColumns, toColumns
51+ , FromExprs, fromResult, toResult
52+ , Transpose
53+ , TTable, TColumns
54+ )
55+import Rel8.Table.Transpose ( Transposes )
56+
57+
58+-- | The kind of 'Rel8able' types
59+type KRel8able :: Type
60+type KRel8able = K.Rel8able
61+
62+
63+-- This is almost 'Data.Type.Equality.==', but we add an extra case.
64+type (==) :: k -> k -> Bool
65+type family a == b where
66+ -- This extra case is needed to solve the equation "a == a" (where a is a
67+ -- KRel8able), which occurs when we have polymorphic Rel8ables
68+ -- (e.g., newtype T t f = T { x :: t a })
69+ (a :: KRel8able) == (a :: KRel8able) = 'True
70+
71+ -- This extra case is needed to solve the equation "a == Identity a",
72+ -- which occurs when we have polymorphic Rel8ables
73+ -- (e.g., newtype T a f = T { x :: Column f a })
74+ a == Identity a = 'False
75+
76+ -- These cases are exactly the same as those in 'Data.Type.Equality.==.
77+ f a == g b = f == g && a == b
78+ a == a = 'True
79+ _ == _ = 'False
80+
81+
82+type Serialize :: Bool -> Type -> Type -> Constraint
83+class transposition ~ (a == Transpose Result expr) =>
84+ Serialize transposition expr a
85+ where
86+ serialize :: a -> Columns expr Result
87+ deserialize :: Columns expr Result -> a
88+
89+
90+instance
91+ ( (a == Transpose Result expr) ~ 'True
92+ , Transposes Expr Result expr a
93+ )
94+ => Serialize 'True expr a
95+ where
96+ serialize = toColumns
97+ deserialize = fromColumns
98+
99+
100+instance
101+ ( (a == Transpose Result expr) ~ 'False
102+ , Table (Context expr) expr
103+ , FromExprs expr ~ a
104+ )
105+ => Serialize 'False expr a
106+ where
107+ serialize = toResult @_ @expr
108+ deserialize = fromResult @_ @expr
109+
110+
111+data TSerialize :: Type -> Type -> Exp Constraint
112+type instance Eval (TSerialize expr a) =
113+ Serialize (a == Transpose Result expr) expr a
114+
115+
116+-- | This type class allows you to define custom 'Table's using higher-kinded
117+-- data types. Higher-kinded data types are data types of the pattern:
118+--
119+-- @
120+-- data MyType f =
121+-- MyType { field1 :: Column f T1 OR HK1 f
122+-- , field2 :: Column f T2 OR HK2 f
123+-- , ...
124+-- , fieldN :: Column f Tn OR HKn f
125+-- }
126+-- @
127+--
128+-- where @Tn@ is any Haskell type, and @HKn@ is any higher-kinded type.
129+--
130+-- That is, higher-kinded data are records where all fields in the record are
131+-- all either of the type @Column f T@ (for any @T@), or are themselves
132+-- higher-kinded data:
133+--
134+-- [Nested]
135+--
136+-- @
137+-- data Nested f =
138+-- Nested { nested1 :: MyType f
139+-- , nested2 :: MyType f
140+-- }
141+-- @
142+--
143+-- The @Rel8able@ type class is used to give us a special mapping operation
144+-- that lets us change the type parameter @f@.
145+--
146+-- [Supplying @Rel8able@ instances]
147+--
148+-- This type class should be derived generically for all table types in your
149+-- project. To do this, enable the @DeriveAnyClass@ and @DeriveGeneric@ language
150+-- extensions:
151+--
152+-- @
153+-- \{\-\# LANGUAGE DeriveAnyClass, DeriveGeneric #-\}
154+--
155+-- data MyType f = MyType { fieldA :: Column f T }
156+-- deriving ( GHC.Generics.Generic, Rel8able )
157+-- @
158+type Rel8able :: K.Rel8able -> Constraint
159+class HTable (GColumns t) => Rel8able t where
160+ type GColumns t :: K.HTable
161+ type GFromExprs t :: Type
162+
163+ gfromColumns :: SContext context -> GColumns t context -> t context
164+ gtoColumns :: SContext context -> t context -> GColumns t context
165+
166+ gfromResult :: GColumns t Result -> GFromExprs t
167+ gtoResult :: GFromExprs t -> GColumns t Result
168+
169+ type GColumns t = G.GColumns TColumns (GRep t Expr)
170+ type GFromExprs t = t Result
171+
172+ default gfromColumns :: forall context.
173+ ( SRel8able t Aggregate
174+ , SRel8able t Expr
175+ , forall table. SRel8able t (Field table)
176+ , SRel8able t Name
177+ , SSerialize t
178+ )
179+ => SContext context -> GColumns t context -> t context
180+ gfromColumns = \case
181+ SAggregate -> sfromColumns
182+ SExpr -> sfromColumns
183+ SField -> sfromColumns
184+ SName -> sfromColumns
185+ SResult -> sfromResult
186+
187+ default gtoColumns :: forall context.
188+ ( SRel8able t Aggregate
189+ , SRel8able t Expr
190+ , forall table. SRel8able t (Field table)
191+ , SRel8able t Name
192+ , SSerialize t
193+ )
194+ => SContext context -> t context -> GColumns t context
195+ gtoColumns = \case
196+ SAggregate -> stoColumns
197+ SExpr -> stoColumns
198+ SField -> stoColumns
199+ SName -> stoColumns
200+ SResult -> stoResult
201+
202+ default gfromResult :: (SSerialize t, GFromExprs t ~ t Result)
203+ => GColumns t Result -> GFromExprs t
204+ gfromResult = sfromResult
205+
206+ default gtoResult :: (SSerialize t, GFromExprs t ~ t Result)
207+ => GFromExprs t -> GColumns t Result
208+ gtoResult = stoResult
209+
210+
211+type Algebra :: K.Rel8able -> K.Algebra
212+type Algebra t = GAlgebra (GRep t Expr)
213+
214+
215+type GRep :: K.Rel8able -> K.Context -> Type -> Type
216+type GRep t context = Rep (Record (t context))
217+
218+
219+type SRel8able :: K.Rel8able -> K.Context -> Constraint
220+class
221+ ( Generic (Record (t context))
222+ , G.GTable (TTable context) TColumns (GRep t context)
223+ , G.GColumns TColumns (GRep t context) ~ GColumns t
224+ )
225+ => SRel8able t context
226+instance
227+ ( Generic (Record (t context))
228+ , G.GTable (TTable context) TColumns (GRep t context)
229+ , G.GColumns TColumns (GRep t context) ~ GColumns t
230+ )
231+ => SRel8able t context
232+
233+
234+type SSerialize :: K.Rel8able -> Constraint
235+type SSerialize t =
236+ ( Generic (Record (t Result))
237+ , G.GSerialize TSerialize TColumns (GRep t Expr) (GRep t Result)
238+ , G.GColumns TColumns (GRep t Expr) ~ GColumns t
239+ )
240+
241+
242+sfromColumns :: forall t context. SRel8able t context
243+ => GColumns t context -> t context
244+sfromColumns =
245+ unrecord .
246+ to .
247+ G.gfromColumns @(TTable context) @TColumns fromColumns
248+
249+
250+stoColumns :: forall t context. SRel8able t context
251+ => t context -> GColumns t context
252+stoColumns =
253+ G.gtoColumns @(TTable context) @TColumns toColumns .
254+ from .
255+ Record
256+
257+
258+sfromResult :: forall t. SSerialize t
259+ => GColumns t Result -> t Result
260+sfromResult =
261+ unrecord .
262+ to .
263+ G.gfromResult
264+ @TSerialize
265+ @TColumns
266+ @(GRep t Expr)
267+ @(GRep t Result)
268+ (\(_ :: proxy x) -> deserialize @_ @x)
269+
270+
271+stoResult :: forall t. SSerialize t
272+ => t Result -> GColumns t Result
273+stoResult =
274+ G.gtoResult
275+ @TSerialize
276+ @TColumns
277+ @(GRep t Expr)
278+ @(GRep t Result)
279+ (\(_ :: proxy x) -> serialize @_ @x) .
280+ from .
281+ Record
src/Rel8/Generic/Table.hsnew file+103
@@ -0,0 +1,103 @@
1+{-# language AllowAmbiguousTypes #-}
2+{-# language DataKinds #-}
3+{-# language FlexibleContexts #-}
4+{-# language FlexibleInstances #-}
5+{-# language MultiParamTypeClasses #-}
6+{-# language RankNTypes #-}
7+{-# language ScopedTypeVariables #-}
8+{-# language StandaloneKindSignatures #-}
9+{-# language TypeApplications #-}
10+{-# language TypeFamilies #-}
11+{-# language TypeOperators #-}
12+{-# language UndecidableInstances #-}
13+
14+module Rel8.Generic.Table
15+ ( GGSerialize, GGColumns, ggfromResult, ggtoResult
16+ , GAlgebra
17+ )
18+where
19+
20+-- base
21+import Data.Kind ( Constraint, Type )
22+import GHC.Generics ( (:+:), (:*:), K1, M1, U1, V1 )
23+import Prelude ()
24+
25+-- rel8
26+import Rel8.FCF ( Eval, Exp )
27+import Rel8.Generic.Table.ADT
28+ ( GSerializeADT, GColumnsADT, gtoResultADT, gfromResultADT
29+ )
30+import Rel8.Generic.Table.Record ( GSerialize, GColumns, gtoResult, gfromResult )
31+import Rel8.Kind.Algebra
32+ ( Algebra( Product, Sum )
33+ , SAlgebra( SProduct, SSum )
34+ , KnownAlgebra, algebraSing
35+ )
36+import qualified Rel8.Schema.Kind as K
37+import Rel8.Schema.Result ( Result )
38+
39+
40+data GGSerialize
41+ :: Algebra
42+ -> (Type -> Type -> Exp Constraint)
43+ -> (Type -> Exp K.HTable)
44+ -> (Type -> Type)
45+ -> (Type -> Type)
46+ -> Exp Constraint
47+
48+
49+type instance Eval (GGSerialize 'Product _Serialize _Columns exprs rep) =
50+ GSerialize _Serialize _Columns exprs rep
51+
52+
53+type instance Eval (GGSerialize 'Sum _Serialize _Columns exprs rep) =
54+ GSerializeADT _Serialize _Columns exprs rep
55+
56+
57+data GGColumns
58+ :: Algebra
59+ -> (Type -> Exp K.HTable)
60+ -> (Type -> Type)
61+ -> Exp K.HTable
62+
63+
64+type instance Eval (GGColumns 'Product _Columns rep) = GColumns _Columns rep
65+
66+
67+type instance Eval (GGColumns 'Sum _Columns rep) = GColumnsADT _Columns rep
68+
69+
70+type GAlgebra :: (Type -> Type) -> Algebra
71+type family GAlgebra rep where
72+ GAlgebra (M1 _ _ rep) = GAlgebra rep
73+ GAlgebra V1 = 'Sum
74+ GAlgebra (_ :+: _) = 'Sum
75+ GAlgebra U1 = 'Sum
76+ GAlgebra (_ :*: _) = 'Product
77+ GAlgebra (K1 _ _) = 'Product
78+
79+
80+ggfromResult :: forall algebra _Serialize _Columns exprs rep x.
81+ ( KnownAlgebra algebra
82+ , Eval (GGSerialize algebra _Serialize _Columns exprs rep)
83+ )
84+ => (forall expr a proxy. Eval (_Serialize expr a)
85+ => proxy expr -> Eval (_Columns expr) Result -> a)
86+ -> Eval (GGColumns algebra _Columns exprs) Result
87+ -> rep x
88+ggfromResult f x = case algebraSing @algebra of
89+ SProduct -> gfromResult @_Serialize @_Columns @exprs @rep f x
90+ SSum -> gfromResultADT @_Serialize @_Columns @exprs @rep f x
91+
92+
93+ggtoResult :: forall algebra _Serialize _Columns exprs rep x.
94+ ( KnownAlgebra algebra
95+ , Eval (GGSerialize algebra _Serialize _Columns exprs rep)
96+ )
97+ => (forall expr a proxy. Eval (_Serialize expr a)
98+ => proxy expr -> a -> Eval (_Columns expr) Result)
99+ -> rep x
100+ -> Eval (GGColumns algebra _Columns exprs) Result
101+ggtoResult f x = case algebraSing @algebra of
102+ SProduct -> gtoResult @_Serialize @_Columns @exprs @rep f x
103+ SSum -> gtoResultADT @_Serialize @_Columns @exprs @rep f x
src/Rel8/Generic/Table/ADT.hsnew file+221
@@ -0,0 +1,221 @@
1+{-# language AllowAmbiguousTypes #-}
2+{-# language DataKinds #-}
3+{-# language FlexibleContexts #-}
4+{-# language FlexibleInstances #-}
5+{-# language LambdaCase #-}
6+{-# language MultiParamTypeClasses #-}
7+{-# language RankNTypes #-}
8+{-# language ScopedTypeVariables #-}
9+{-# language StandaloneKindSignatures #-}
10+{-# language TypeApplications #-}
11+{-# language TypeFamilies #-}
12+{-# language TypeOperators #-}
13+{-# language UndecidableInstances #-}
14+
15+module Rel8.Generic.Table.ADT
16+ ( GSerializeADT, GColumnsADT, gfromResultADT, gtoResultADT
17+ , GSerializeADT', GColumnsADT'
18+ )
19+where
20+
21+-- base
22+import Data.Functor.Identity ( Identity( Identity ) )
23+import Data.Kind ( Constraint, Type )
24+import Data.Proxy ( Proxy( Proxy ) )
25+import GHC.Generics
26+ ( (:+:)( L1, R1 ), M1( M1 ), U1( U1 )
27+ , C, D
28+ , Meta( MetaCons )
29+ )
30+import GHC.TypeLits ( KnownSymbol, symbolVal )
31+import Prelude hiding ( null )
32+
33+-- rel8
34+import Rel8.FCF ( Eval, Exp )
35+import Rel8.Generic.Table.Record ( GSerialize, GColumns, gfromResult, gtoResult )
36+import Rel8.Schema.HTable ( HTable )
37+import Rel8.Schema.HTable.Identity ( HIdentity( HIdentity ) )
38+import Rel8.Schema.HTable.Label ( HLabel, hlabel, hunlabel )
39+import Rel8.Schema.HTable.Nullify ( HNullify, hnulls, hnullify, hunnullify )
40+import Rel8.Schema.HTable.Product ( HProduct( HProduct ) )
41+import qualified Rel8.Schema.Kind as K
42+import Rel8.Schema.Result ( Result, null, nullifier, unnullifier )
43+import Rel8.Type.Tag ( Tag( Tag ) )
44+
45+-- text
46+import Data.Text ( pack )
47+
48+
49+type GColumnsADT
50+ :: (Type -> Exp K.HTable)
51+ -> (Type -> Type) -> K.HTable
52+type family GColumnsADT _Columns rep where
53+ GColumnsADT _Columns (M1 D _ rep) =
54+ GColumnsADT' _Columns (HLabel "tag" (HIdentity Tag)) rep
55+
56+
57+type GColumnsADT'
58+ :: (Type -> Exp K.HTable)
59+ -> K.HTable -> (Type -> Type) -> K.HTable
60+type family GColumnsADT' _Columns htable rep where
61+ GColumnsADT' _Columns htable (a :+: b) =
62+ GColumnsADT' _Columns (GColumnsADT' _Columns htable a) b
63+ GColumnsADT' _Columns htable (M1 C ('MetaCons _ _ _) U1) = htable
64+ GColumnsADT' _Columns htable (M1 C ('MetaCons label _ _) rep) =
65+ HProduct htable (HLabel label (HNullify (GColumns _Columns rep)))
66+
67+
68+type GSerializeADT
69+ :: (Type -> Type -> Exp Constraint)
70+ -> (Type -> Exp K.HTable)
71+ -> (Type -> Type) -> (Type -> Type) -> Constraint
72+class GSerializeADT _Serialize _Columns exprs rep where
73+ gfromResultADT :: ()
74+ => (forall expr a proxy. Eval (_Serialize expr a)
75+ => proxy expr -> Eval (_Columns expr) Result -> a)
76+ -> GColumnsADT _Columns exprs Result
77+ -> rep x
78+
79+ gtoResultADT :: ()
80+ => (forall expr a proxy. Eval (_Serialize expr a)
81+ => proxy expr -> a -> Eval (_Columns expr) Result)
82+ -> rep x
83+ -> GColumnsADT _Columns exprs Result
84+
85+
86+instance
87+ ( htable ~ HLabel "tag" (HIdentity Tag)
88+ , GSerializeADT' _Serialize _Columns htable exprs rep
89+ )
90+ => GSerializeADT _Serialize _Columns (M1 D meta exprs) (M1 D meta rep)
91+ where
92+ gfromResultADT fromResult columns =
93+ case gfromResultADT' @_Serialize @_Columns @htable @exprs @rep fromResult tag columns of
94+ Just rep -> M1 rep
95+ _ -> error "ADT.fromColumns: mismatch between tag and data"
96+ where
97+ tag = (\(HIdentity (Identity a)) -> a) . hunlabel @"tag"
98+
99+ gtoResultADT toResult (M1 rep) =
100+ gtoResultADT' @_Serialize @_Columns @htable @exprs @rep toResult tag (Just rep)
101+ where
102+ tag = hlabel @"tag" . HIdentity . Identity
103+
104+
105+type GSerializeADT'
106+ :: (Type -> Type -> Exp Constraint)
107+ -> (Type -> Exp K.HTable)
108+ -> K.HTable -> (Type -> Type) -> (Type -> Type) -> Constraint
109+class GSerializeADT' _Serialize _Columns htable exprs rep where
110+ gfromResultADT' :: context ~ Result
111+ => (forall expr a proxy. Eval (_Serialize expr a)
112+ => proxy expr -> Eval (_Columns expr) context -> a)
113+ -> (htable Result -> Tag)
114+ -> GColumnsADT' _Columns htable exprs context
115+ -> Maybe (rep x)
116+
117+ gtoResultADT' :: context ~ Result
118+ => (forall expr a proxy. Eval (_Serialize expr a)
119+ => proxy expr -> a -> Eval (_Columns expr) context)
120+ -> (Tag -> htable Result)
121+ -> Maybe (rep x)
122+ -> GColumnsADT' _Columns htable exprs context
123+
124+ extract :: GColumnsADT' _Columns htable exprs context -> htable context
125+
126+
127+instance
128+ ( htable' ~ GColumnsADT' _Columns htable exprs1
129+ , GSerializeADT' _Serialize _Columns htable exprs1 a
130+ , GSerializeADT' _Serialize _Columns htable' exprs2 b
131+ )
132+ => GSerializeADT' _Serialize _Columns htable (exprs1 :+: exprs2) (a :+: b)
133+ where
134+ gfromResultADT' fromResult f columns =
135+ case ma of
136+ Just a -> Just (L1 a)
137+ Nothing -> R1 <$>
138+ gfromResultADT' @_Serialize @_Columns @_ @exprs2 @b
139+ fromResult
140+ (f . extract @_Serialize @_Columns @_ @exprs1 @a)
141+ columns
142+ where
143+ ma =
144+ gfromResultADT' @_Serialize @_Columns @_ @exprs1 @a
145+ fromResult
146+ f
147+ (extract @_Serialize @_Columns @_ @exprs2 @b columns)
148+
149+ gtoResultADT' toResult tag = \case
150+ Just (L1 a) ->
151+ gtoResultADT' @_Serialize @_Columns @_ @exprs2 @b
152+ toResult
153+ (\_ -> gtoResultADT' @_Serialize @_Columns @_ @exprs1 @a
154+ toResult
155+ tag
156+ (Just a))
157+ Nothing
158+ Just (R1 b) ->
159+ gtoResultADT' @_Serialize @_Columns @_ @exprs2 @b
160+ toResult
161+ (\tag' ->
162+ gtoResultADT' @_Serialize @_Columns @_ @exprs1 @a
163+ toResult
164+ (\_ -> tag tag')
165+ Nothing)
166+ (Just b)
167+ Nothing ->
168+ gtoResultADT' @_Serialize @_Columns @_ @exprs2 @b
169+ toResult
170+ (\_ -> gtoResultADT' @_Serialize @_Columns @_ @exprs1 @a toResult tag Nothing)
171+ Nothing
172+
173+ extract =
174+ extract @_Serialize @_Columns @_ @exprs1 @a .
175+ extract @_Serialize @_Columns @_ @exprs2 @b
176+
177+
178+instance (meta ~ 'MetaCons label _fixity _isRecord, KnownSymbol label) =>
179+ GSerializeADT' _Serialize _Columns _htable (M1 C meta U1) (M1 C meta U1)
180+ where
181+ gfromResultADT' _ tag columns
182+ | tag columns == tag' = Just (M1 U1)
183+ | otherwise = Nothing
184+ where
185+ tag' = Tag $ pack $ symbolVal (Proxy @label)
186+
187+ gtoResultADT' _ tag _ = tag tag'
188+ where
189+ tag' = Tag $ pack $ symbolVal (Proxy @label)
190+
191+ extract = id
192+
193+
194+instance {-# OVERLAPPABLE #-}
195+ ( HTable (GColumns _Columns exprs)
196+ , GSerialize _Serialize _Columns exprs rep
197+ , meta ~ 'MetaCons label _fixity _isRecord
198+ , KnownSymbol label
199+ , GColumnsADT' _Columns htable (M1 C ('MetaCons label _fixity _isRecord) exprs) ~
200+ HProduct htable (HLabel label (HNullify (GColumns _Columns exprs)))
201+ )
202+ => GSerializeADT' _Serialize _Columns htable (M1 C meta exprs) (M1 C meta rep)
203+ where
204+ gfromResultADT' fromResult tag (HProduct a b)
205+ | tag a == tag' =
206+ M1 . gfromResult @_Serialize @_Columns @exprs @rep fromResult <$>
207+ hunnullify unnullifier (hunlabel b)
208+ | otherwise = Nothing
209+ where
210+ tag' = Tag $ pack $ symbolVal (Proxy @label)
211+
212+ gtoResultADT' toResult tag = \case
213+ Nothing -> HProduct (tag tag') (hlabel (hnulls (const null)))
214+ Just (M1 rep) -> HProduct (tag tag') $
215+ hlabel $
216+ hnullify nullifier $
217+ gtoResult @_Serialize @_Columns @exprs @rep toResult rep
218+ where
219+ tag' = Tag $ pack $ symbolVal (Proxy @label)
220+
221+ extract (HProduct a _) = a
src/Rel8/Generic/Table/Record.hsnew file+181
@@ -0,0 +1,181 @@
1+{-# language AllowAmbiguousTypes #-}
2+{-# language DataKinds #-}
3+{-# language FlexibleContexts #-}
4+{-# language FlexibleInstances #-}
5+{-# language MultiParamTypeClasses #-}
6+{-# language PolyKinds #-}
7+{-# language RankNTypes #-}
8+{-# language ScopedTypeVariables #-}
9+{-# language StandaloneKindSignatures #-}
10+{-# language TypeApplications #-}
11+{-# language TypeFamilies #-}
12+{-# language TypeOperators #-}
13+{-# language UndecidableInstances #-}
14+
15+module Rel8.Generic.Table.Record
16+ ( GTable, GColumns, GContext, gfromColumns, gtoColumns, gtable
17+ , GSerialize, gfromResult, gtoResult
18+ )
19+where
20+
21+-- base
22+import Data.Kind ( Constraint, Type )
23+import Data.Proxy ( Proxy( Proxy ) )
24+import GHC.Generics
25+ ( (:*:)( (:*:) ), K1( K1 ), M1( M1 )
26+ , C, D, S
27+ , Meta( MetaSel )
28+ )
29+import Prelude hiding ( null )
30+
31+-- rel8
32+import Rel8.FCF ( Eval, Exp )
33+import Rel8.Schema.HTable.Label ( HLabel, hlabel, hunlabel )
34+import Rel8.Schema.HTable.Product ( HProduct(..) )
35+import qualified Rel8.Schema.Kind as K
36+
37+
38+type GColumns :: (Type -> Exp K.HTable) -> (Type -> Type) -> K.HTable
39+type family GColumns _Columns rep where
40+ GColumns _Columns (M1 D _ rep) = GColumns _Columns rep
41+ GColumns _Columns (M1 C _ rep) = GColumns _Columns rep
42+ GColumns _Columns (rep1 :*: rep2) =
43+ HProduct (GColumns _Columns rep1) (GColumns _Columns rep2)
44+ GColumns _Columns (M1 S ('MetaSel ('Just label) _ _ _) (K1 _ a)) =
45+ HLabel label (Eval (_Columns a))
46+
47+
48+type GContext :: (Type -> Exp K.Context) -> (Type -> Type) -> K.Context
49+type family GContext _Context rep where
50+ GContext _Context (M1 _ _ rep) = GContext _Context rep
51+ GContext _Context (rep1 :*: _rep2) = GContext _Context rep1
52+ GContext _Context (K1 _ a) = Eval (_Context a)
53+
54+
55+type GTable
56+ :: (Type -> Exp Constraint)
57+ -> (Type -> Exp K.HTable)
58+ -> (Type -> Type) -> Constraint
59+class GTable _Table _Columns rep
60+ where
61+ gfromColumns :: ()
62+ => (forall a. Eval (_Table a) => Eval (_Columns a) context -> a)
63+ -> GColumns _Columns rep context
64+ -> rep x
65+
66+ gtoColumns :: ()
67+ => (forall a. Eval (_Table a) => a -> Eval (_Columns a) context)
68+ -> rep x
69+ -> GColumns _Columns rep context
70+
71+ gtable :: ()
72+ => (forall a proxy. Eval (_Table a) => proxy a -> Eval (_Columns a) context)
73+ -> GColumns _Columns rep context
74+
75+
76+type GSerialize
77+ :: (Type -> Type -> Exp Constraint)
78+ -> (Type -> Exp K.HTable)
79+ -> (Type -> Type) -> (Type -> Type) -> Constraint
80+class GSerialize _Serialize _Columns exprs rep
81+ where
82+ gfromResult :: ()
83+ => (forall expr a proxy. Eval (_Serialize expr a)
84+ => proxy expr -> Eval (_Columns expr) context -> a)
85+ -> GColumns _Columns exprs context
86+ -> rep x
87+
88+ gtoResult :: ()
89+ => (forall expr a proxy. Eval (_Serialize expr a)
90+ => proxy expr -> a -> Eval (_Columns expr) context)
91+ -> rep x
92+ -> GColumns _Columns exprs context
93+
94+
95+instance GTable _Table _Columns rep => GTable _Table _Columns (M1 D c rep)
96+ where
97+ gfromColumns fromColumns =
98+ M1 . gfromColumns @_Table @_Columns @rep fromColumns
99+ gtoColumns toColumns (M1 a) =
100+ gtoColumns @_Table @_Columns @rep toColumns a
101+ gtable = gtable @_Table @_Columns @rep
102+
103+
104+instance GSerialize _Serialize _Columns exprs rep =>
105+ GSerialize _Serialize _Columns (M1 D c exprs) (M1 D c rep)
106+ where
107+ gfromResult fromResult =
108+ M1 . gfromResult @_Serialize @_Columns @exprs @rep fromResult
109+ gtoResult toResult (M1 a) =
110+ gtoResult @_Serialize @_Columns @exprs @rep toResult a
111+
112+
113+instance GTable _Table _Columns rep => GTable _Table _Columns (M1 C c rep)
114+ where
115+ gfromColumns fromColumns =
116+ M1 . gfromColumns @_Table @_Columns @rep fromColumns
117+ gtoColumns toColumns (M1 a) =
118+ gtoColumns @_Table @_Columns @rep toColumns a
119+ gtable = gtable @_Table @_Columns @rep
120+
121+
122+instance GSerialize _Serialize _Columns exprs rep =>
123+ GSerialize _Serialize _Columns (M1 C c exprs) (M1 C c rep)
124+ where
125+ gfromResult fromResult =
126+ M1 . gfromResult @_Serialize @_Columns @exprs @rep fromResult
127+ gtoResult toResult (M1 a) =
128+ gtoResult @_Serialize @_Columns @exprs @rep toResult a
129+
130+
131+instance (GTable _Table _Columns rep1, GTable _Table _Columns rep2) =>
132+ GTable _Table _Columns (rep1 :*: rep2)
133+ where
134+ gfromColumns fromColumns (HProduct a b) =
135+ gfromColumns @_Table @_Columns @rep1 fromColumns a :*:
136+ gfromColumns @_Table @_Columns @rep2 fromColumns b
137+ gtoColumns toColumns (a :*: b) = HProduct
138+ (gtoColumns @_Table @_Columns @rep1 toColumns a)
139+ (gtoColumns @_Table @_Columns @rep2 toColumns b)
140+ gtable table = HProduct
141+ (gtable @_Table @_Columns @rep1 table)
142+ (gtable @_Table @_Columns @rep2 table)
143+
144+
145+instance
146+ ( GSerialize _Serialize _Columns expr1 rep1
147+ , GSerialize _Serialize _Columns expr2 rep2
148+ )
149+ => GSerialize _Serialize _Columns (expr1 :*: expr2) (rep1 :*: rep2)
150+ where
151+ gfromResult fromResult (HProduct a b) =
152+ gfromResult @_Serialize @_Columns @expr1 @rep1 fromResult a :*:
153+ gfromResult @_Serialize @_Columns @expr2 @rep2 fromResult b
154+ gtoResult toResult (a :*: b) =
155+ HProduct
156+ (gtoResult @_Serialize @_Columns @expr1 @rep1 toResult a)
157+ (gtoResult @_Serialize @_Columns @expr2 @rep2 toResult b)
158+
159+
160+instance
161+ ( Eval (_Table a)
162+ , meta ~ 'MetaSel ('Just label) _su _ss _ds
163+ , k1 ~ K1 i a
164+ )
165+ => GTable _Table _Columns (M1 S meta k1)
166+ where
167+ gfromColumns fromColumns = M1 . K1 . fromColumns . hunlabel
168+ gtoColumns toColumns (M1 (K1 a)) = hlabel (toColumns a)
169+ gtable table = hlabel (table (Proxy @a))
170+
171+
172+instance
173+ ( Eval (_Serialize expr a)
174+ , meta ~ 'MetaSel ('Just label) _su _ss _ds
175+ , k1 ~ K1 i expr
176+ , k1' ~ K1 i a
177+ )
178+ => GSerialize _Serialize _Columns (M1 S meta k1) (M1 S meta k1')
179+ where
180+ gfromResult fromResult = M1 . K1 . fromResult (Proxy @expr) . hunlabel
181+ gtoResult toResult (M1 (K1 a)) = hlabel (toResult (Proxy @expr) a)
src/Rel8/Kind/Algebra.hsnew file+38
@@ -0,0 +1,38 @@
1+{-# language DataKinds #-}
2+{-# language FlexibleContexts #-}
3+{-# language GADTs #-}
4+{-# language StandaloneKindSignatures #-}
5+
6+module Rel8.Kind.Algebra
7+ ( Algebra( Product, Sum )
8+ , SAlgebra( SProduct, SSum )
9+ , KnownAlgebra( algebraSing )
10+ )
11+where
12+
13+-- base
14+import Data.Kind ( Constraint, Type )
15+import Prelude ()
16+
17+
18+type Algebra :: Type
19+data Algebra = Product | Sum
20+
21+
22+type SAlgebra :: Algebra -> Type
23+data SAlgebra algebra where
24+ SProduct :: SAlgebra 'Product
25+ SSum :: SAlgebra 'Sum
26+
27+
28+type KnownAlgebra :: Algebra -> Constraint
29+class KnownAlgebra algebra where
30+ algebraSing :: SAlgebra algebra
31+
32+
33+instance KnownAlgebra 'Product where
34+ algebraSing = SProduct
35+
36+
37+instance KnownAlgebra 'Sum where
38+ algebraSing = SSum
src/Rel8/Kind/Context.hsnew file+56
@@ -0,0 +1,56 @@
1+{-# language DataKinds #-}
2+{-# language GADTs #-}
3+{-# language StandaloneKindSignatures #-}
4+{-# language TypeSynonymInstances #-}
5+
6+module Rel8.Kind.Context
7+ ( Reifiable( contextSing )
8+ , SContext(..)
9+ )
10+where
11+
12+-- base
13+import Data.Kind ( Constraint, Type )
14+import Prelude ()
15+
16+-- rel8
17+import Rel8.Aggregate ( Aggregate )
18+import Rel8.Expr ( Expr )
19+import Rel8.Schema.Field ( Field )
20+import Rel8.Schema.Kind ( Context )
21+import Rel8.Schema.Name ( Name )
22+import Rel8.Schema.Result ( Result )
23+
24+
25+type SContext :: Context -> Type
26+data SContext context where
27+ SAggregate :: SContext Aggregate
28+ SExpr :: SContext Expr
29+ SField :: SContext (Field table)
30+ SName :: SContext Name
31+ SResult :: SContext Result
32+
33+
34+type Reifiable :: Context -> Constraint
35+class Reifiable context where
36+ contextSing :: SContext context
37+
38+
39+instance Reifiable Aggregate where
40+ contextSing = SAggregate
41+
42+
43+instance Reifiable Expr where
44+ contextSing = SExpr
45+
46+
47+instance Reifiable (Field table) where
48+ contextSing = SField
49+
50+
51+instance Reifiable Result where
52+ contextSing = SResult
53+
54+
55+instance Reifiable Name where
56+ contextSing = SName
src/Rel8/Kind/Labels.hsdeleted−61
@@ -1,61 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language FlexibleContexts #-}
3−{-# language FlexibleInstances #-}
4−{-# language GADTs #-}
5−{-# language LambdaCase #-}
6−{-# language StandaloneKindSignatures #-}
7−{-# language TypeOperators #-}
8−
9−module Rel8.Kind.Labels
10− ( Labels
11− , SLabels( SLabel, SLabels )
12− , KnownLabels( labelsSing )
13− , renderLabels
14− )
15−where
16−
17−-- base
18−import Data.Kind ( Constraint, Type )
19−import Data.List.NonEmpty ( NonEmpty( (:|) ), (<|) )
20−import Data.Proxy ( Proxy( Proxy ) )
21−import GHC.TypeLits ( KnownSymbol, Symbol, symbolVal )
22−import Prelude
23−
24−
25−type Labels :: Type
26−type Labels = [Symbol]
27−
28−
29−type SLabels :: Labels -> Type
30−data SLabels labels where
31− SLabel :: KnownSymbol label => Proxy label -> SLabels '[label]
32− SLabels :: KnownSymbol label => Proxy label -> SLabels labels -> SLabels (label ': labels)
33−
34−
35−type KnownLabels :: Labels -> Constraint
36−class KnownLabels labels where
37− labelsSing :: SLabels labels
38−
39−
40−instance KnownSymbol label => KnownLabels (label ': '[]) where
41− labelsSing = SLabel Proxy
42−
43−
44−instance (KnownSymbol label, KnownLabels (label_ ': labels)) =>
45− KnownLabels (label ': (label_ ': labels))
46− where
47− labelsSing = SLabels Proxy labelsSing
48−
49−
50−renderLabels :: SLabels labels -> NonEmpty String
51−renderLabels = cleanup . go
52− where
53− go :: SLabels labels -> NonEmpty String
54− go = \case
55− SLabel label -> pure (symbolVal label)
56− SLabels label labels -> symbolVal label <| go labels
57−
58− cleanup ("" :| []) = "anon" :| []
59− cleanup (a :| []) = a :| []
60− cleanup (a :| [""]) = a :| []
61− cleanup (a :| (b : c)) = a <| cleanup (b :| c)
src/Rel8/Kind/Necessity.hsdeleted−38
@@ -1,38 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language FlexibleContexts #-}
3−{-# language GADTs #-}
4−{-# language StandaloneKindSignatures #-}
5−
6−module Rel8.Kind.Necessity
7− ( Necessity( Optional, Required )
8− , SNecessity( SOptional, SRequired )
9− , KnownNecessity( necessitySing )
10− )
11−where
12−
13−-- base
14−import Data.Kind ( Constraint, Type )
15−import Prelude ()
16−
17−
18−type Necessity :: Type
19−data Necessity = Optional | Required
20−
21−
22−type SNecessity :: Necessity -> Type
23−data SNecessity necessity where
24− SOptional :: SNecessity 'Optional
25− SRequired :: SNecessity 'Required
26−
27−
28−type KnownNecessity :: Necessity -> Constraint
29−class KnownNecessity necessity where
30− necessitySing :: SNecessity necessity
31−
32−
33−instance KnownNecessity 'Optional where
34− necessitySing = SOptional
35−
36−
37−instance KnownNecessity 'Required where
38− necessitySing = SRequired
src/Rel8/Opaque.hsdeleted−20
@@ -1,20 +0,0 @@
1−{-# language PolyKinds #-}
2−{-# language StandaloneKindSignatures #-}
3−
4−module Rel8.Opaque
5− ( Opaque
6− , Opaque1
7− )
8−where
9−
10−-- base
11−import Data.Kind ( Type )
12−import Prelude ()
13−
14−
15−type Opaque :: Type
16−data Opaque
17−
18−
19−type Opaque1 :: k -> Type -> Type
20−data Opaque1 a x
src/Rel8/Order.hs+7−1
@@ -16,9 +16,15 @@ import Prelude
1616import Data.Functor.Contravariant.Divisible ( Decidable, Divisible )
1717
1818-- opaleye
19−import qualified Opaleye.Internal.Order as Opaleye
19+import qualified Opaleye.Order as Opaleye
2020
2121
22+-- | An ordering expression for @a@. Primitive orderings are defined with
23+-- 'Rel8.asc' and 'Rel8.desc', and you can combine @Order@ via its various
24+-- instances.
25+--
26+-- A common pattern is to use '<>' to combine multiple orderings in sequence,
27+-- and 'Data.Functor.Contravariant.>$<' to select individual columns.
2228type Order :: Type -> Type
2329newtype Order a = Order (Opaleye.Order a)
2430 deriving newtype (Contravariant, Divisible, Decidable, Semigroup, Monoid)
src/Rel8/Query.hs+192−5
@@ -1,6 +1,6 @@
1−{-# language DerivingStrategies #-}
2−{-# language GeneralizedNewtypeDeriving #-}
1+{-# language FlexibleContexts #-}
32{-# language StandaloneKindSignatures #-}
3+{-# language UndecidableInstances #-}
44
55module Rel8.Query
66 ( Query( Query )
@@ -8,29 +8,216 @@ module Rel8.Query
88where
99
1010-- base
11+import Control.Applicative ( liftA2 )
12+import Control.Monad ( liftM2 )
1113import Data.Kind ( Type )
14+import Data.Monoid ( Any( Any ) )
1215import Prelude
1316
1417-- opaleye
15−import qualified Opaleye.Select as Opaleye
18+import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
19+import qualified Opaleye.Internal.PackMap as Opaleye
20+import qualified Opaleye.Internal.PrimQuery as Opaleye hiding (lateral)
21+import qualified Opaleye.Internal.QueryArr as Opaleye
22+import qualified Opaleye.Internal.Tag as Opaleye
1623
1724-- rel8
25+import Rel8.Expr ( Expr )
1826import Rel8.Query.Set ( unionAll )
27+import Rel8.Query.Opaleye ( fromOpaleye )
1928import Rel8.Query.Values ( values )
29+import Rel8.Table ( Table, fromColumns, toColumns )
2030import Rel8.Table.Alternative
2131 ( AltTable, (<|>:)
2232 , AlternativeTable, emptyTable
2333 )
34+import Rel8.Table.Projection ( Projectable, apply, project )
2435
36+-- semigroupoids
37+import Data.Functor.Apply ( Apply, (<.>) )
38+import Data.Functor.Bind ( Bind, (>>-) )
2539
40+
41+-- | The @Query@ monad allows you to compose a @SELECT@ query. This monad has
42+-- semantics similar to the list (@[]@) monad.
2643type Query :: Type -> Type
27−newtype Query a = Query (Opaleye.Select a)
28− deriving newtype (Functor, Applicative, Monad)
44+newtype Query a =
45+ Query (
46+ -- This is based on Opaleye's Select monad, but with two addtions. We
47+ -- maintain a stack of PrimExprs from parent previous subselects. In
48+ -- practice, these are always the results of dummy calls to random().
49+ --
50+ -- We also return a Bool that indicates to the parent subselect whether
51+ -- or not that stack of PrimExprs were used at any point. If they weren't,
52+ -- then the call to random() is never added to the query.
53+ --
54+ -- This is all needed to implement evaluate. Consider the following code:
55+ --
56+ -- do
57+ -- x <- values [lit 'a', lit 'b', lit 'c']
58+ -- y <- evaluate $ nextval "user_id_seq"
59+ -- pure (x, y)
60+ --
61+ -- If we just used Opaleye's Select monad directly, the SQL would come out
62+ -- like this:
63+ --
64+ -- SELECT
65+ -- a, b
66+ -- FROM
67+ -- (VALUES ('a'), ('b'), ('c')) Q1(a),
68+ -- LATERAL (SELECT nextval('user_id_seq')) Q2(b);
69+ --
70+ -- From the Haskell code, you would intuitively expect to get back the
71+ -- results of three different calls to nextval(), but from Postgres' point
72+ -- of view, because the Q2 subquery doesn't reference anything from the Q1
73+ -- query, it thinks it only needs to call nextval() once. This is actually
74+ -- exactly the same problem you get with the deprecated ListT IO monad from
75+ -- the transformers package — *> behaves differently to >>=, so
76+ -- using ApplicativeDo can change the results of a program. ApplicativeDo
77+ -- is exactly the optimisation Postgres does on a "LATERAL" query that
78+ -- doesn't make any references to previous subselects.
79+ --
80+ -- Rel8's solution is generate the following SQL instead:
81+ --
82+ -- SELECT
83+ -- a, b
84+ -- FROM
85+ -- (SELECT
86+ -- random() AS dummy,
87+ -- *
88+ -- FROM
89+ -- (VALUES ('a'), ('b'), ('c')) Q1(a)) Q1,
90+ -- LATERAL (SELECT
91+ -- CASE
92+ -- WHEN dummy IS NOT NULL
93+ -- THEN nextval('user_id_seq')
94+ -- END) Q2(b);
95+ --
96+ -- We use random() here as the dummy value (and not some constant) because
97+ -- Postgres will again optimize if it sees that a value is constant
98+ -- (and thus only call nextval() once), but because random() is marked as
99+ -- VOLATILE, this inhibits Postgres from doing that optimisation.
100+ --
101+ -- Why not just reference the a column from the previous query directly
102+ -- instead of adding a dummy value? Basically, even if we extract out all
103+ -- the bindings introduced in a PrimQuery, we can't always be sure which
104+ -- ones refer to constant values, so if we end up laterally referencing a
105+ -- constant value, then all of this would be for nothing.
106+ --
107+ -- Why not just add the call to the previous subselect directly, like so:
108+ --
109+ -- SELECT
110+ -- a, b
111+ -- FROM
112+ -- (SELECT
113+ -- nextval('user_id_seq') AS eval,
114+ -- *
115+ -- FROM
116+ -- (VALUES ('a'), ('b'), ('c')) Q1(a)) Q1,
117+ -- LATERAL (SELECT eval) Q2(b);
118+ --
119+ -- That would work in this case. But consider the following Rel8 code:
120+ --
121+ -- do
122+ -- x <- values [lit 'a', lit 'b', lit 'c']
123+ -- y <- values [lit 'd', lit 'e', lit 'f']
124+ -- z <- evaluate $ nextval "user_id_seq"
125+ -- pure (x, y, z)
126+ --
127+ -- How many calls to nextval should there be? Our Haskell intuition says
128+ -- nine. But that's not what you would get if you used the above
129+ -- technique. The problem is, which VALUES query should the nextval be
130+ -- added to? You can choose one or the other to get three calls to
131+ -- nextval, but you still need to make a superfluous LATERAL references to
132+ -- the other if you want nine calls. So for the above Rel8 code we generate
133+ -- the following SQL:
134+ --
135+ -- SELECT
136+ -- a, b, c
137+ -- FROM
138+ -- (SELECT
139+ -- random() AS dummy,
140+ -- *
141+ -- FROM
142+ -- (VALUES ('a'), ('b'), ('c')) Q1(a)) Q1,
143+ -- (SELECT
144+ -- random() AS dummy,
145+ -- *
146+ -- FROM
147+ -- (VALUES ('d'), ('e'), ('f')) Q2(b)) Q2,
148+ -- LATERAL (SELECT
149+ -- CASE
150+ -- WHEN Q1.dummy IS NOT NULL AND Q2.dummy IS NOT NULL
151+ -- THEN nextval('user_id_seq')
152+ -- END) Q3(c);
153+ --
154+ -- This gives nine calls to nextval() as we would expect.
155+ [Opaleye.PrimExpr] -> Opaleye.Select (Any, a)
156+ )
157+
158+
159+instance Projectable Query where
160+ project f = fmap (fromColumns . apply f . toColumns)
161+
162+
163+instance Functor Query where
164+ fmap f (Query a) = Query (fmap (fmap (fmap f)) a)
165+
166+
167+instance Apply Query where
168+ (<.>) = (<*>)
169+
29170
171+instance Applicative Query where
172+ pure = fromOpaleye . pure
173+ liftA2 = liftM2
30174
175+
176+instance Bind Query where
177+ (>>-) = (>>=)
178+
179+
180+instance Monad Query where
181+ Query q >>= f = Query $ \dummies -> Opaleye.stateQueryArr $ \_ tag ->
182+ let
183+ qa = q dummies
184+ ((m, a), query, tag') = Opaleye.runStateQueryArr qa () tag
185+ Query q' = f a
186+ (dummies', query', tag'') =
187+ ( dummy : dummies
188+ , query <> Opaleye.aRebind bindings
189+ , Opaleye.next tag'
190+ )
191+ where
192+ (dummy, bindings) = Opaleye.run $ name random
193+ where
194+ random = Opaleye.FunExpr "random" []
195+ name = Opaleye.extractAttr "dummy" tag'
196+ qa' = Opaleye.lateral $ \_ -> q' dummies'
197+ ((m'@(Any needsDummies), b), query'', tag''') = Opaleye.runStateQueryArr qa' () tag''
198+ query'''
199+ | needsDummies = query' <> query''
200+ | otherwise = query <> query''
201+ m'' = m <> m'
202+ in
203+ ((m'', b), query''', tag''')
204+
205+
206+-- | '<|>:' = 'unionAll'.
31207instance AltTable Query where
32208 (<|>:) = unionAll
33209
34210
211+-- | 'emptyTable' = 'values' @[]@.
35212instance AlternativeTable Query where
36213 emptyTable = values []
214+
215+
216+-- | '<>' = 'unionAll'.
217+instance Table Expr a => Semigroup (Query a) where
218+ (<>) = (<|>:)
219+
220+
221+-- | 'mempty' = @'values' []@.
222+instance Table Expr a => Monoid (Query a) where
223+ mempty = emptyTable
src/Rel8/Query.hs-boot+3−1
@@ -7,11 +7,13 @@ where
77
88-- base
99import Data.Kind ( Type )
10+import Data.Monoid ( Any )
1011import Prelude ()
1112
1213-- opaleye
14+import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
1315import qualified Opaleye.Select as Opaleye
1416
1517
1618type Query :: Type -> Type
17−newtype Query a = Query (Opaleye.Select a)
19+newtype Query a = Query ([Opaleye.PrimExpr] -> Opaleye.Select (Any, a))
src/Rel8/Query/Aggregate.hs+37−3
@@ -1,22 +1,56 @@
11{-# language FlexibleContexts #-}
2+{-# language MonoLocalBinds #-}
3+{-# language ScopedTypeVariables #-}
4+{-# language TypeApplications #-}
25
36module Rel8.Query.Aggregate
47 ( aggregate
8+ , countRows
9+ , mode
510 )
611where
712
813-- base
9−import Prelude ()
14+import Data.Functor.Contravariant ( (>$<) )
15+import Data.Int ( Int64 )
16+import Prelude
1017
1118-- opaleye
1219import qualified Opaleye.Aggregate as Opaleye
1320
1421-- rel8
15−import Rel8.Aggregate ( Aggregate )
22+import Rel8.Aggregate ( Aggregates )
23+import Rel8.Expr ( Expr )
24+import Rel8.Expr.Aggregate ( countStar )
25+import Rel8.Expr.Order ( desc )
1626import Rel8.Query ( Query )
27+import Rel8.Query.Limit ( limit )
28+import Rel8.Query.Maybe ( optional )
1729import Rel8.Query.Opaleye ( mapOpaleye )
30+import Rel8.Query.Order ( orderBy )
31+import Rel8.Table ( toColumns )
32+import Rel8.Table.Aggregate ( hgroupBy )
33+import Rel8.Table.Cols ( Cols( Cols ), fromCols )
34+import Rel8.Table.Eq ( EqTable, eqTable )
1835import Rel8.Table.Opaleye ( aggregator )
36+import Rel8.Table.Maybe ( maybeTable )
1937
2038
21−aggregate :: Query (Aggregate exprs) -> Query exprs
39+-- | Apply an aggregation to all rows returned by a 'Query'.
40+aggregate :: Aggregates aggregates exprs => Query aggregates -> Query exprs
2241aggregate = mapOpaleye (Opaleye.aggregate aggregator)
42+
43+
44+-- | Count the number of rows returned by a query. Note that this is different
45+-- from @countStar@, as even if the given query yields no rows, @countRows@
46+-- will return @0@.
47+countRows :: Query a -> Query (Expr Int64)
48+countRows = fmap (maybeTable 0 id) . optional . aggregate . fmap (const countStar)
49+
50+
51+-- | Return the most common row in a query.
52+mode :: forall a. EqTable a => Query a -> Query a
53+mode rows = limit 1 $ fmap (fromCols . snd) $ orderBy (fst >$< desc) $ do
54+ aggregate $ do
55+ row <- toColumns <$> rows
56+ pure (countStar, Cols $ hgroupBy (eqTable @a) row)
src/Rel8/Query/Distinct.hs+12−9
@@ -1,5 +1,3 @@
1−{-# options_ghc -fno-warn-redundant-constraints #-}
2−
31module Rel8.Query.Distinct
42 ( distinct
53 , distinctOn
@@ -8,12 +6,11 @@ module Rel8.Query.Distinct
86where
97
108-- base
11−import Prelude
9+import Prelude ()
1210
1311-- opaleye
1412import qualified Opaleye.Distinct as Opaleye
15−import qualified Opaleye.Internal.Order as Opaleye
16−import qualified Opaleye.Internal.QueryArr as Opaleye
13+import qualified Opaleye.Order as Opaleye
1714
1815-- rel8
1916import Rel8.Order ( Order( Order ) )
@@ -23,15 +20,21 @@ import Rel8.Table.Eq ( EqTable )
2320import Rel8.Table.Opaleye ( distinctspec, unpackspec )
2421
2522
23+-- | Select all distinct rows from a query, removing duplicates. @distinct q@
24+-- is equivalent to the SQL statement @SELECT DISTINCT q@.
2625distinct :: EqTable a => Query a -> Query a
2726distinct = mapOpaleye (Opaleye.distinctExplicit distinctspec)
2827
2928
29+-- | Select all distinct rows from a query, where rows are equivalent according
30+-- to a projection. If multiple rows have the same projection, it is
31+-- unspecified which row will be returned. If this matters, use 'distinctOnBy'.
3032distinctOn :: EqTable b => (a -> b) -> Query a -> Query a
31−distinctOn proj =
32− mapOpaleye (\q -> Opaleye.productQueryArr (Opaleye.distinctOn unpackspec proj . Opaleye.runSimpleQueryArr q))
33+distinctOn proj = mapOpaleye (Opaleye.distinctOnExplicit unpackspec proj)
3334
3435
36+-- | Select all distinct rows from a query, where rows are equivalent according
37+-- to a projection. If there are multiple rows with the same projection, the
38+-- first row according to the specified 'Order' will be returned.
3539distinctOnBy :: EqTable b => (a -> b) -> Order a -> Query a -> Query a
36−distinctOnBy proj (Order order) =
37− mapOpaleye (\q -> Opaleye.productQueryArr (Opaleye.distinctOnBy unpackspec proj order . Opaleye.runSimpleQueryArr q))
40+distinctOnBy proj (Order order) = mapOpaleye (Opaleye.distinctOnByExplicit unpackspec proj order)
src/Rel8/Query/Each.hs+7−4
@@ -1,4 +1,5 @@
11{-# language FlexibleContexts #-}
2+{-# language MonoLocalBinds #-}
23
34module Rel8.Query.Each
45 ( each
@@ -14,16 +15,18 @@ import qualified Opaleye.Table as Opaleye
1415-- rel8
1516import Rel8.Query ( Query )
1617import Rel8.Query.Opaleye ( fromOpaleye )
18+import Rel8.Schema.Name ( Selects )
1719import Rel8.Schema.Table ( TableSchema )
18−import Rel8.Table ( fromColumns, toColumns )
20+import Rel8.Table.Cols ( fromCols, toCols )
1921import Rel8.Table.Opaleye ( table, unpackspec )
20−import Rel8.Table.Recontextualize ( Selects )
2122
2223
24+-- | Select each row from a table definition. This is equivalent to @FROM
25+-- table@.
2326each :: Selects names exprs => TableSchema names -> Query exprs
2427each =
25− fmap fromColumns .
28+ fmap fromCols .
2629 fromOpaleye .
2730 Opaleye.selectTableExplicit unpackspec .
2831 table .
29− fmap toColumns
32+ fmap toCols
src/Rel8/Query/Either.hs+35−30
@@ -3,7 +3,6 @@
33module Rel8.Query.Either
44 ( keepLeftTable
55 , keepRightTable
6− , bindEitherTable
76 , bitraverseEitherTable
87 )
98where
@@ -11,54 +10,60 @@ where
1110-- base
1211import Prelude
1312
13+-- comonad
14+import Control.Comonad ( extract )
15+
1416-- rel8
17+import Rel8.Expr ( Expr )
1518import Rel8.Expr.Eq ( (==.) )
1619import Rel8.Query ( Query )
1720import Rel8.Query.Filter ( where_ )
1821import Rel8.Query.Maybe ( optional )
19−import Rel8.Query.Set ( unionAll )
20−import Rel8.Schema.Context ( DB )
21−import Rel8.Table ( Table )
22−import Rel8.Table.Bool ( bool )
2322import Rel8.Table.Either
2423 ( EitherTable( EitherTable )
25− , leftTable, rightTable
2624 , isLeftTable, isRightTable
2725 )
2826import Rel8.Table.Maybe ( MaybeTable( MaybeTable ), isJustTable )
2927
3028
31−keepLeftTable :: EitherTable a b -> Query a
29+-- | Filter 'EitherTable's, keeping only 'leftTable's.
30+keepLeftTable :: EitherTable Expr a b -> Query a
3231keepLeftTable e@(EitherTable _ a _) = do
3332 where_ $ isLeftTable e
34− pure a
33+ pure (extract a)
3534
3635
37−keepRightTable :: EitherTable a b -> Query b
36+-- | Filter 'EitherTable's, keeping only 'rightTable's.
37+keepRightTable :: EitherTable Expr a b -> Query b
3838keepRightTable e@(EitherTable _ _ b) = do
3939 where_ $ isRightTable e
40− pure b
41−
42−
43−bindEitherTable :: (Table DB a, Monad m)
44− => (i -> m (EitherTable a b)) -> EitherTable a i -> m (EitherTable a b)
45−bindEitherTable query e@(EitherTable input a i) = do
46− EitherTable output a' b <- query i
47− pure $ EitherTable (input <> output) (bool a a' (isRightTable e)) b
40+ pure (extract b)
4841
4942
50−bitraverseEitherTable :: (Table DB c, Table DB d)
43+-- | @bitraverseEitherTable f g x@ will pass all @leftTable@s through @f@ and
44+-- all @rightTable@s through @g@. The results are then lifted back into
45+-- @leftTable@ and @rightTable@, respectively. This is similar to 'bitraverse'
46+-- for 'Either'.
47+--
48+-- For example,
49+--
50+-- >>> :{
51+-- select do
52+-- x <- values (map lit [ Left True, Right (42 :: Int32) ])
53+-- bitraverseEitherTable (\y -> values [y, not_ y]) (\y -> pure (y * 100)) x
54+-- :}
55+-- [ Left True
56+-- , Left False
57+-- , Right 4200
58+-- ]
59+bitraverseEitherTable :: ()
5160 => (a -> Query c)
5261 -> (b -> Query d)
53− -> EitherTable a b
54− -> Query (EitherTable c d)
55−bitraverseEitherTable f g e = traverseLeftTable `unionAll` traverseRightTable
56− where
57− traverseLeftTable = do
58− mc@(MaybeTable _ c) <- optional (f =<< keepLeftTable e)
59− where_ $ isJustTable mc ==. isLeftTable e
60− pure $ leftTable c
61− traverseRightTable = do
62− md@(MaybeTable _ d) <- optional (g =<< keepRightTable e)
63− where_ $ isJustTable md ==. isRightTable e
64− pure $ rightTable d
62+ -> EitherTable Expr a b
63+ -> Query (EitherTable Expr c d)
64+bitraverseEitherTable f g e@(EitherTable tag _ _) = do
65+ mc@(MaybeTable _ c) <- optional (f =<< keepLeftTable e)
66+ md@(MaybeTable _ d) <- optional (g =<< keepRightTable e)
67+ where_ $ isJustTable mc ==. isLeftTable e
68+ where_ $ isJustTable md ==. isRightTable e
69+ pure $ EitherTable tag c d
src/Rel8/Query/Evaluate.hsnew file+49
@@ -0,0 +1,49 @@
1+{-# language FlexibleContexts #-}
2+{-# language TupleSections #-}
3+
4+module Rel8.Query.Evaluate
5+ ( evaluate
6+ )
7+where
8+
9+-- base
10+import Control.Monad ( (>=>) )
11+import Data.Foldable ( foldl' )
12+import Data.List.NonEmpty ( NonEmpty( (:|) ), nonEmpty )
13+import Data.Monoid ( Any( Any ) )
14+import Prelude hiding ( undefined )
15+
16+-- opaleye
17+import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
18+
19+-- rel8
20+import Rel8.Expr ( Expr )
21+import Rel8.Expr.Bool ( (&&.) )
22+import Rel8.Expr.Opaleye ( fromPrimExpr )
23+import Rel8.Query ( Query( Query ) )
24+import Rel8.Query.Rebind ( rebind )
25+import Rel8.Table ( Table )
26+import Rel8.Table.Bool ( case_ )
27+import Rel8.Table.Undefined ( undefined )
28+
29+
30+-- | 'evaluate' takes expressions that could potentially have side effects and
31+-- \"runs\" them in the 'Query' monad. The returned expressions have no side
32+-- effects and can safely be reused.
33+evaluate :: Table Expr a => a -> Query a
34+evaluate = laterally >=> rebind "eval"
35+
36+
37+laterally :: Table Expr a => a -> Query a
38+laterally a = Query $ \bindings -> pure $ (Any True,) $
39+ case nonEmpty bindings of
40+ Nothing -> a
41+ Just bindings' -> case_ [(condition, a)] undefined
42+ where
43+ condition = foldl1' (&&.) (fmap go bindings')
44+ where
45+ go = fromPrimExpr . Opaleye.UnExpr Opaleye.OpIsNotNull
46+
47+
48+foldl1' :: (a -> a -> a) -> NonEmpty a -> a
49+foldl1' f (a :| as) = foldl' f a as
src/Rel8/Query/Exists.hs+22−13
@@ -2,8 +2,8 @@
22
33module Rel8.Query.Exists
44 ( exists, inQuery
5− , whereExists, with, withBy
6− , whereNotExists, without, withoutBy
5+ , present, with, withBy
6+ , absent, without, withoutBy
77 )
88where
99
@@ -11,47 +11,56 @@ where
1111import Prelude hiding ( filter )
1212
1313-- opaleye
14+import qualified Opaleye.Exists as Opaleye
1415import qualified Opaleye.Operators as Opaleye
1516
1617-- rel8
1718import Rel8.Expr ( Expr )
19+import Rel8.Expr.Opaleye ( fromColumn, fromPrimExpr )
1820import Rel8.Query ( Query )
1921import Rel8.Query.Filter ( filter )
20−import Rel8.Query.Maybe ( optional )
2122import Rel8.Query.Opaleye ( mapOpaleye )
2223import Rel8.Table.Eq ( EqTable, (==:) )
23−import Rel8.Table.Maybe ( isJustTable )
2424
2525
26+-- | Checks if a query returns at least one row.
2627exists :: Query a -> Query (Expr Bool)
27−exists = fmap isJustTable . optional . whereExists
28−-- FIXME: change this when b7aacc07c6392654cae439fc3b997620c3aa7a87 makes it
29−-- into a release of Opaleye
28+exists = fmap (fromPrimExpr . fromColumn) . mapOpaleye Opaleye.exists
3029
3130
3231inQuery :: EqTable a => a -> Query a -> Query (Expr Bool)
3332inQuery a = exists . (>>= filter (a ==:))
3433
3534
36−whereExists :: Query a -> Query ()
37−whereExists = mapOpaleye Opaleye.restrictExists
35+-- | Produce the empty query if the given query returns no rows. @present@
36+-- is equivalent to @WHERE EXISTS@ in SQL.
37+present :: Query a -> Query ()
38+present = mapOpaleye Opaleye.restrictExists
3839
3940
40−whereNotExists :: Query a -> Query ()
41−whereNotExists = mapOpaleye Opaleye.restrictNotExists
41+-- | Produce the empty query if the given query returns rows. @absent@
42+-- is equivalent to @WHERE NOT EXISTS@ in SQL.
43+absent :: Query a -> Query ()
44+absent = mapOpaleye Opaleye.restrictNotExists
4245
4346
47+-- | @with@ is similar to 'filter', but allows the predicate to be a full query.
48+--
49+-- @with f a = a <$ present (f a)@, but this form matches 'filter'.
4450with :: (a -> Query b) -> a -> Query a
45−with f a = a <$ whereExists (f a)
51+with f a = a <$ present (f a)
4652
4753
54+-- | Like @with@, but with a custom membership test.
4855withBy :: (a -> b -> Expr Bool) -> Query b -> a -> Query a
4956withBy predicate bs = with $ \a -> bs >>= filter (predicate a)
5057
5158
59+-- | Filter rows where @a -> Query b@ yields no rows.
5260without :: (a -> Query b) -> a -> Query a
53−without f a = a <$ whereNotExists (f a)
61+without f a = a <$ absent (f a)
5462
5563
64+-- | Like @without@, but with a custom membership test.
5665withoutBy :: (a -> b -> Expr Bool) -> Query b -> a -> Query a
5766withoutBy predicate bs = without $ \a -> bs >>= filter (predicate a)
src/Rel8/Query/Filter.hs+6
@@ -20,10 +20,16 @@ import Rel8.Query ( Query )
2020import Rel8.Query.Opaleye ( fromOpaleye )
2121
2222
23+-- | @filter f x@ will be a zero-row query when @f x@ is @False@, and will
24+-- return @x@ unchanged when @f x@ is @True@. This is similar to
25+-- 'Control.Monad.guard', but as the predicate is separate from the argument,
26+-- it is easy to use in a pipeline of 'Query' transformations.
2327filter :: (a -> Expr Bool) -> a -> Query a
2428filter f a = a <$ where_ (f a)
2529
2630
31+-- | Drop any rows that don't match a predicate. @where_ expr@ is equivalent
32+-- to the SQL @WHERE expr@.
2733where_ :: Expr Bool -> Query ()
2834where_ condition =
2935 fromOpaleye $ lmap (\_ -> toColumn $ toPrimExpr condition) Opaleye.restrict
src/Rel8/Query/Indexed.hsnew file+21
@@ -0,0 +1,21 @@
1+module Rel8.Query.Indexed
2+ ( indexed
3+ )
4+where
5+
6+-- base
7+import Control.Applicative ( liftA2 )
8+import Data.Int ( Int64 )
9+import Prelude
10+
11+-- rel8
12+import Rel8.Expr ( Expr )
13+import Rel8.Expr.Window ( rowNumber )
14+import Rel8.Query ( Query )
15+import Rel8.Query.Window ( window )
16+import Rel8.Table.Window ( currentRow )
17+
18+
19+-- | Pair each row of a query with its index within the query.
20+indexed :: Query a -> Query (Expr Int64, a)
21+indexed = window (liftA2 (,) (subtract 1 <$> rowNumber) currentRow)
src/Rel8/Query/Limit.hs+4
@@ -15,9 +15,13 @@ import Rel8.Query ( Query )
1515import Rel8.Query.Opaleye ( mapOpaleye )
1616
1717
18+-- | @limit n@ select at most @n@ rows from a query. @limit n@ is equivalent
19+-- to the SQL @LIMIT n@.
1820limit :: Word -> Query a -> Query a
1921limit = mapOpaleye . Opaleye.limit . fromIntegral
2022
2123
24+-- | @offset n@ drops the first @n@ rows from a query. @offset n@ is equivalent
25+-- to the SQL @OFFSET n@.
2226offset :: Word -> Query a -> Query a
2327offset = mapOpaleye . Opaleye.offset . fromIntegral
src/Rel8/Query/List.hs+102−8
@@ -1,28 +1,122 @@
11{-# language FlexibleContexts #-}
2+{-# language GADTs #-}
3+{-# language NamedFieldPuns #-}
24
35module Rel8.Query.List
46 ( many, some
7+ , manyExpr, someExpr
8+ , catListTable, catNonEmptyTable
9+ , catList, catNonEmpty
510 )
611where
712
813-- base
14+import Data.Functor.Identity ( runIdentity )
15+import Data.List.NonEmpty ( NonEmpty )
916import Prelude
1017
18+-- opaleye
19+import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
20+
1121-- rel8
22+import Rel8.Expr ( Expr )
23+import Rel8.Expr.Aggregate ( listAggExpr, nonEmptyAggExpr )
24+import Rel8.Expr.Opaleye ( mapPrimExpr )
1225import Rel8.Query ( Query )
1326import Rel8.Query.Aggregate ( aggregate )
1427import Rel8.Query.Maybe ( optional )
15−import Rel8.Schema.Context ( DB )
16−import Rel8.Table ( Table )
28+import Rel8.Query.Rebind ( rebind )
29+import Rel8.Schema.HTable.Vectorize ( hunvectorize )
30+import Rel8.Schema.Null ( Sql, Unnullify )
31+import Rel8.Schema.Spec ( Spec( Spec, info ) )
32+import Rel8.Table ( Table, fromColumns )
33+import Rel8.Table.Cols ( toCols )
1734import Rel8.Table.Aggregate ( listAgg, nonEmptyAgg )
18−import Rel8.Table.List ( ListTable )
35+import Rel8.Table.List ( ListTable( ListTable ) )
1936import Rel8.Table.Maybe ( maybeTable )
20−import Rel8.Table.NonEmpty ( NonEmptyTable )
37+import Rel8.Table.NonEmpty ( NonEmptyTable( NonEmptyTable ) )
38+import Rel8.Type ( DBType, typeInformation )
39+import Rel8.Type.Array ( extractArrayElement )
40+import Rel8.Type.Information ( TypeInformation )
41+
42+
43+-- | Aggregate a 'Query' into a 'ListTable'. If the supplied query returns 0
44+-- rows, this function will produce a 'Query' that returns one row containing
45+-- the empty @ListTable@. If the supplied @Query@ does return rows, @many@ will
46+-- return exactly one row, with a @ListTable@ collecting all returned rows.
47+--
48+-- @many@ is analogous to 'Control.Applicative.many' from
49+-- @Control.Applicative@.
50+many :: Table Expr a => Query a -> Query (ListTable Expr a)
51+many =
52+ fmap (maybeTable mempty (\(ListTable a) -> ListTable a)) .
53+ optional .
54+ aggregate .
55+ fmap (listAgg . toCols)
56+
57+
58+-- | Aggregate a 'Query' into a 'NonEmptyTable'. If the supplied query returns
59+-- 0 rows, this function will produce a 'Query' that is empty - that is, will
60+-- produce zero @NonEmptyTable@s. If the supplied @Query@ does return rows,
61+-- @some@ will return exactly one row, with a @NonEmptyTable@ collecting all
62+-- returned rows.
63+--
64+-- @some@ is analogous to 'Control.Applicative.some' from
65+-- @Control.Applicative@.
66+some :: Table Expr a => Query a -> Query (NonEmptyTable Expr a)
67+some =
68+ fmap (\(NonEmptyTable a) -> NonEmptyTable a) .
69+ aggregate .
70+ fmap (nonEmptyAgg . toCols)
71+
72+
73+-- | A version of 'many' specialised to single expressions.
74+manyExpr :: Sql DBType a => Query (Expr a) -> Query (Expr [a])
75+manyExpr = fmap (maybeTable mempty id) . optional . aggregate . fmap listAggExpr
76+
77+
78+-- | A version of 'many' specialised to single expressions.
79+someExpr :: Sql DBType a => Query (Expr a) -> Query (Expr (NonEmpty a))
80+someExpr = aggregate . fmap nonEmptyAggExpr
81+
82+
83+-- | Expand a 'ListTable' into a 'Query', where each row in the query is an
84+-- element of the given @ListTable@.
85+--
86+-- @catListTable@ is an inverse to 'many'.
87+catListTable :: Table Expr a => ListTable Expr a -> Query a
88+catListTable (ListTable as) =
89+ rebind "unnest" $ fromColumns $ runIdentity $
90+ hunvectorize (\Spec {info} -> pure . sunnest info) as
91+
92+
93+-- | Expand a 'NonEmptyTable' into a 'Query', where each row in the query is an
94+-- element of the given @NonEmptyTable@.
95+--
96+-- @catNonEmptyTable@ is an inverse to 'some'.
97+catNonEmptyTable :: Table Expr a => NonEmptyTable Expr a -> Query a
98+catNonEmptyTable (NonEmptyTable as) =
99+ rebind "unnest" $ fromColumns $ runIdentity $
100+ hunvectorize (\Spec {info} -> pure . sunnest info) as
101+
102+
103+-- | Expand an expression that contains a list into a 'Query', where each row
104+-- in the query is an element of the given list.
105+--
106+-- @catList@ is an inverse to 'manyExpr'.
107+catList :: Sql DBType a => Expr [a] -> Query (Expr a)
108+catList = rebind "unnest" . sunnest typeInformation
21109
22110
23−some :: Table DB a => Query a -> Query (NonEmptyTable a)
24−some = aggregate . fmap nonEmptyAgg
111+-- | Expand an expression that contains a non-empty list into a 'Query', where
112+-- each row in the query is an element of the given list.
113+--
114+-- @catNonEmpty@ is an inverse to 'someExpr'.
115+catNonEmpty :: Sql DBType a => Expr (NonEmpty a) -> Query (Expr a)
116+catNonEmpty = rebind "unnest" . sunnest typeInformation
25117
26118
27−many :: Table DB a => Query a -> Query (ListTable a)
28−many = fmap (maybeTable mempty id) . optional . aggregate . fmap listAgg
119+sunnest :: TypeInformation (Unnullify a) -> Expr (list a) -> Expr a
120+sunnest info = mapPrimExpr $
121+ extractArrayElement info .
122+ Opaleye.UnExpr (Opaleye.UnOpOther "UNNEST")
src/Rel8/Query/Maybe.hs+42−34
@@ -1,7 +1,10 @@
1+{-# language GADTs #-}
2+{-# language LambdaCase #-}
3+{-# language NamedFieldPuns #-}
4+
15module Rel8.Query.Maybe
26 ( optional
37 , catMaybeTable
4− , bindMaybeTable
58 , traverseMaybeTable
69 )
710where
@@ -9,52 +12,57 @@ where
912-- base
1013import Prelude
1114
15+-- comonad
16+import Control.Comonad ( extract )
17+
1218-- opaleye
13−import qualified Opaleye.Internal.PackMap as Opaleye
14−import qualified Opaleye.Internal.PrimQuery as Opaleye
15−import qualified Opaleye.Internal.QueryArr as Opaleye
16−import qualified Opaleye.Internal.Tag as Opaleye
17−import qualified Opaleye.Internal.Unpackspec as Opaleye
19+import qualified Opaleye.Internal.MaybeFields as Opaleye
1820
1921-- rel8
20−import Rel8.Expr.Bool ( true )
22+import Rel8.Expr ( Expr )
2123import Rel8.Expr.Eq ( (==.) )
22−import Rel8.Expr.Opaleye ( toPrimExpr )
24+import Rel8.Expr.Opaleye ( fromColumn, fromPrimExpr )
2325import Rel8.Query ( Query )
2426import Rel8.Query.Filter ( where_ )
2527import Rel8.Query.Opaleye ( mapOpaleye )
26−import Rel8.Table.Maybe ( MaybeTable( MaybeTable ), isJustTable )
27−import Rel8.Table.Opaleye ( unpackspec )
28+import Rel8.Table.Maybe ( MaybeTable(..), isJustTable )
2829
2930
30−optional :: Query a -> Query (MaybeTable a)
31−optional = mapOpaleye $ Opaleye.QueryArr . go
32− where
33− go query (i, left, tag) = (MaybeTable t' a, join, Opaleye.next tag')
34− where
35− (MaybeTable t a, right, tag') =
36− Opaleye.runSimpleQueryArr (pure <$> query) (i, tag)
37− (t', bindings) = Opaleye.run $
38− Opaleye.runUnpackspec unpackspec (Opaleye.extractAttr "maybe" tag') t
39− join = Opaleye.Join Opaleye.LeftJoin condition [] bindings left right
40− condition = toPrimExpr true
31+-- | Convert a query that might return zero rows to a query that always returns
32+-- at least one row.
33+--
34+-- To speak in more concrete terms, 'optional' is most useful to write @LEFT
35+-- JOIN@s.
36+optional :: Query a -> Query (MaybeTable Expr a)
37+optional = mapOpaleye $ Opaleye.optionalInternal $ \tag a -> MaybeTable
38+ { tag = fromPrimExpr $ fromColumn tag
39+ , just = pure a
40+ }
4141
4242
43−catMaybeTable :: MaybeTable a -> Query a
43+-- | Filter out 'MaybeTable's, returning only the tables that are not-null.
44+--
45+-- This operation can be used to "undo" the effect of 'optional', which
46+-- operationally is like turning a @LEFT JOIN@ back into a full @JOIN@. You
47+-- can think of this as analogous to 'Data.Maybe.catMaybes'.
48+catMaybeTable :: MaybeTable Expr a -> Query a
4449catMaybeTable ma@(MaybeTable _ a) = do
4550 where_ $ isJustTable ma
46− pure a
47−
48−
49−bindMaybeTable :: Monad m
50− => (a -> m (MaybeTable b)) -> MaybeTable a -> m (MaybeTable b)
51−bindMaybeTable query (MaybeTable input a) = do
52− MaybeTable output b <- query a
53− pure $ MaybeTable (input <> output) b
51+ pure (extract a)
5452
5553
56−traverseMaybeTable :: (a -> Query b) -> MaybeTable a -> Query (MaybeTable b)
54+-- | Extend an optional query with another query. This is useful if you want
55+-- to step through multiple @LEFT JOINs@.
56+--
57+-- Note that @traverseMaybeTable@ takes a @a -> Query b@ function, which means
58+-- you also have the ability to "expand" one row into multiple rows. If the
59+-- @a -> Query b@ function returns no rows, then the resulting query will also
60+-- have no rows. However, regardless of the given @a -> Query b@ function, if
61+-- the input is @nothingTable@, you will always get exactly one @nothingTable@
62+-- back.
63+traverseMaybeTable :: (a -> Query b) -> MaybeTable Expr a -> Query (MaybeTable Expr b)
5764traverseMaybeTable query ma@(MaybeTable input _) = do
58− MaybeTable output b <- optional (query =<< catMaybeTable ma)
59− where_ $ output ==. input
60− pure $ MaybeTable input b
65+ optional (query =<< catMaybeTable ma) >>= \case
66+ MaybeTable output b -> do
67+ where_ $ output ==. input
68+ pure $ MaybeTable input b
src/Rel8/Query/Null.hs+18−18
@@ -1,5 +1,8 @@
1+{-# language FlexibleContexts #-}
2+
13module Rel8.Query.Null
2− ( catNullable
4+ ( catNull
5+ , catNullTable
36 )
47where
58
@@ -9,6 +12,8 @@ import Prelude
912-- rel8
1013import Rel8.Expr ( Expr )
1114import Rel8.Expr.Null ( isNonNull, unsafeUnnullify )
15+import Rel8.Table ( Table )
16+import Rel8.Table.Null ( NullTable, isNonNullTable, unsafeUnnullifyTable )
1217import Rel8.Query ( Query )
1318import Rel8.Query.Filter ( where_ )
1419
@@ -17,22 +22,17 @@ import Rel8.Query.Filter ( where_ )
1722-- @null@s.
1823--
1924-- Corresponds to 'Data.Maybe.catMaybes'.
20−--
21−-- >>> select c $ pure (nullExpr :: Expr (Maybe Bool))
22−-- [Nothing]
23−--
24−-- >>> select c $ catNullable (nullExpr :: Expr (Maybe Bool))
25−-- []
26−--
27−-- >>> select c $ catNullable (lit (Just True))
28−-- [True]
29−--
30−-- Notice how in the last example a @Bool@ is returned (rather than @Maybe
31−-- Bool@):
32−--
33−-- >>> :t catNullable (lit (Just True))
34−-- catMaybe (lit (Just True)) :: Query (Expr Bool)
35−catNullable :: Expr (Maybe a) -> Query (Expr a)
36−catNullable a = do
25+catNull :: Expr (Maybe a) -> Query (Expr a)
26+catNull a = do
3727 where_ $ isNonNull a
3828 pure $ unsafeUnnullify a
29+
30+
31+-- | Filter a 'Query' that might return @nullTable@ to a 'Query' without any
32+-- @nullTable@s.
33+--
34+-- Corresponds to 'Data.Maybe.catMaybes'.
35+catNullTable :: Table Expr a => NullTable Expr a -> Query a
36+catNullTable a = do
37+ where_ $ isNonNullTable a
38+ pure $ unsafeUnnullifyTable a
src/Rel8/Query/Opaleye.hs+41−5
@@ -1,34 +1,70 @@
1+{-# language TupleSections #-}
2+
13module Rel8.Query.Opaleye
24 ( fromOpaleye
35 , toOpaleye
46 , mapOpaleye
57 , zipOpaleyeWith
8+ , unsafePeekQuery
69 )
710where
811
912-- base
13+import Control.Applicative ( liftA2 )
1014import Prelude
1115
1216-- opaleye
13−import qualified Opaleye.Select as Opaleye
17+import qualified Opaleye.Internal.QueryArr as Opaleye
18+import qualified Opaleye.Internal.Tag as Opaleye
1419
1520-- rel8
1621import {-# SOURCE #-} Rel8.Query ( Query( Query ) )
1722
1823
1924fromOpaleye :: Opaleye.Select a -> Query a
20−fromOpaleye = Query
25+fromOpaleye = Query . pure . fmap pure
2126
2227
2328toOpaleye :: Query a -> Opaleye.Select a
24−toOpaleye (Query a) = a
29+toOpaleye (Query a) = snd <$> a mempty
2530
2631
2732mapOpaleye :: (Opaleye.Select a -> Opaleye.Select b) -> Query a -> Query b
28−mapOpaleye f = fromOpaleye . f . toOpaleye
33+mapOpaleye f (Query a) = Query (fmap (mapping f) a)
2934
3035
3136zipOpaleyeWith :: ()
3237 => (Opaleye.Select a -> Opaleye.Select b -> Opaleye.Select c)
3338 -> Query a -> Query b -> Query c
34−zipOpaleyeWith f a b = fromOpaleye $ f (toOpaleye a) (toOpaleye b)
39+zipOpaleyeWith f (Query a) (Query b) = Query $ liftA2 (zipping f) a b
40+
41+
42+unsafePeekQuery :: Query a -> a
43+unsafePeekQuery (Query q) = case q mempty of
44+ f -> case Opaleye.runStateQueryArr f () Opaleye.start of
45+ ((_, a), _, _) -> a
46+
47+
48+mapping :: ()
49+ => (Opaleye.Select a -> Opaleye.Select b)
50+ -> Opaleye.Select (m, a) -> Opaleye.Select (m, b)
51+mapping f q = Opaleye.stateQueryArr $ \_ tag ->
52+ let
53+ ((m, _), _, _) = Opaleye.runStateQueryArr q () tag
54+ q' = (m,) <$> f (snd <$> q)
55+ in
56+ Opaleye.runStateQueryArr q' () tag
57+
58+
59+zipping :: Semigroup m
60+ => (Opaleye.Select a -> Opaleye.Select b -> Opaleye.Select c)
61+ -> Opaleye.Select (m, a) -> Opaleye.Select (m, b) -> Opaleye.Select (m, c)
62+zipping f q q' =
63+ Opaleye.stateQueryArr $ \_ tag ->
64+ let
65+ ((m, _), _, _) = Opaleye.runStateQueryArr q () tag
66+ ((m', _), _, _) = Opaleye.runStateQueryArr q' () tag
67+ m'' = m <> m'
68+ q'' = (m'',) <$> f (snd <$> q) (snd <$> q')
69+ in
70+ Opaleye.runStateQueryArr q'' () tag
src/Rel8/Query/Optimize.hsdeleted−200
@@ -1,200 +0,0 @@
1−{-# language ApplicativeDo #-}
2−{-# language LambdaCase #-}
3−
4−{-# options -fno-warn-name-shadowing #-}
5−
6−module Rel8.Query.Optimize
7− ( optimize
8− )
9−where
10−
11−-- base
12−import Control.Applicative
13−import Data.Functor.Identity
14−import Prelude
15−
16−-- opaleye
17−import Opaleye.Internal.HaskellDB.PrimQuery
18−import Opaleye.Internal.PrimQuery
19−
20−
21−optimize :: PrimQuery' a -> PrimQuery' a
22−optimize =
23− transformOf primQuery optimisePredicates
24−
25−
26−primQuery
27− :: Applicative f
28− => ( PrimQuery' a -> f ( PrimQuery' a ) ) -> PrimQuery' a -> f ( PrimQuery' a )
29−primQuery f = \case
30− Aggregate bindingsAndPrimExpr primQuery -> do
31− primQuery <- f primQuery
32−
33− return ( Aggregate bindingsAndPrimExpr primQuery )
34−
35− DistinctOnOrderBy maybePrimExprs orderExprs primQuery -> do
36− primQuery <- f primQuery
37−
38− return ( DistinctOnOrderBy maybePrimExprs orderExprs primQuery )
39−
40− Limit limitOp primQuery -> do
41− primQuery <- f primQuery
42−
43− return ( Limit limitOp primQuery )
44−
45− Join joinType primExpr bindingsA bindingsB primQueryA primQueryB -> do
46− primQueryA <- f primQueryA
47− primQueryB <- f primQueryB
48−
49− return ( Join joinType primExpr bindingsA bindingsB primQueryA primQueryB )
50−
51− Exists bool primQueryA primQueryB -> do
52− primQueryA <- f primQueryA
53− primQueryB <- f primQueryB
54−
55− return ( Exists bool primQueryA primQueryB )
56−
57− Binary binOp primQueries -> do
58− primQueries <- both f primQueries
59−
60− return ( Binary binOp primQueries )
61−
62− Label label primQuery -> do
63− primQuery <- f primQuery
64−
65− return ( Label label primQuery )
66−
67− other ->
68− pure other
69−
70−
71−optimisePredicates :: PrimQuery' a -> PrimQuery' a
72−optimisePredicates = \case
73− Join joinType predicate bindingsA bindingsB primQueryA primQueryB ->
74− Join joinType ( nullIsFalse predicate ) bindingsA bindingsB primQueryA primQueryB
75−
76− other ->
77− other
78−
79−
80−nullIsFalse :: PrimExpr -> PrimExpr
81−nullIsFalse =
82− rewriteOf primExprs simplifyCaseAnalysis
83−
84− where
85−
86− simplifyCaseAnalysis = \case
87− CaseExpr [ ( UnExpr OpIsNull _, ConstExpr ( BoolLit False ) ) ] notNullBranch ->
88− Just notNullBranch
89−
90− CaseExpr [ ( UnExpr OpIsNull x, UnExpr OpIsNull y ) ] notNullBranch ->
91− Just
92− ( BinExpr
93− (:||)
94− ( BinExpr (:&&) ( UnExpr OpIsNull x ) ( UnExpr OpIsNull y ) )
95− notNullBranch
96− )
97−
98− _ ->
99− Nothing
100−
101−
102−
103−-- | Traverse all immediate 'PrimExpr's
104−primExprs :: Applicative f => ( PrimExpr -> f PrimExpr ) -> PrimExpr -> f PrimExpr
105−primExprs f = \case
106− AttrExpr ( Symbol string tag ) ->
107− pure ( AttrExpr ( Symbol string tag ) )
108−
109− BaseTableAttrExpr attribute ->
110− pure ( BaseTableAttrExpr attribute )
111−
112− CompositeExpr primExpr attribute -> do
113− primExpr <- f primExpr
114−
115− return ( CompositeExpr primExpr attribute )
116−
117− BinExpr binOp a b -> do
118− a <- f a
119− b <- f b
120−
121− return ( BinExpr binOp a b )
122−
123− UnExpr unOp primExpr -> do
124− primExpr <- f primExpr
125−
126− return ( UnExpr unOp primExpr )
127−
128− AggrExpr aggrDistinct aggrOp primExpr orderExprs -> do
129− aggrOp <- aggrOpPrimExprs f aggrOp
130− primExpr <- f primExpr
131− orderExprs <- traverse ( orderExprPrimExprs f ) orderExprs
132−
133− return ( AggrExpr aggrDistinct aggrOp primExpr orderExprs )
134−
135− ConstExpr l ->
136− pure ( ConstExpr l )
137−
138− CaseExpr cases def -> do
139− cases <- traverse ( both f ) cases
140− def <- f def
141−
142− return ( CaseExpr cases def )
143−
144− other ->
145− pure other
146−
147−
148−
149−aggrOpPrimExprs :: Applicative f => ( PrimExpr -> f PrimExpr ) -> AggrOp -> f AggrOp
150−aggrOpPrimExprs f = \case
151− AggrStringAggr primExpr -> do
152− primExpr <- f primExpr
153−
154− return ( AggrStringAggr primExpr )
155−
156− other ->
157− pure other
158−
159−
160−orderExprPrimExprs :: Applicative f => ( PrimExpr -> f PrimExpr ) -> OrderExpr -> f OrderExpr
161−orderExprPrimExprs f ( OrderExpr orderOp primExpr ) = do
162− primExpr <- f primExpr
163−
164− return ( OrderExpr orderOp primExpr )
165−
166−
167−-- | Traverse both sides of a homogeneous tuple.
168−both :: Applicative f => ( t -> f b ) -> ( t, t ) -> f ( b, b )
169−both f ( a,b ) =
170− liftA2 (,) ( f a ) ( f b )
171−
172−
173−rewriteOf
174− :: ( ( a -> Identity a ) -> a -> Identity a )
175− -> ( a -> Maybe a ) -> a -> a
176−rewriteOf l f =
177− go where
178−
179− go = transformOf l ( \x -> maybe x go ( f x ) )
180−
181−
182−transformOf
183− :: ( ( a -> Identity a ) -> a -> Identity a )
184− -> ( a -> a )
185− -> a
186− -> a
187−{-# inline transformOf #-}
188−transformOf l f = go where
189−
190− go =
191− f . over l go
192−
193−
194−over
195− :: ( ( s -> Identity t ) -> a -> Identity b )
196− -> ( s -> t )
197− -> a
198− -> b
199−over l f =
200− runIdentity . l (Identity . f)
src/Rel8/Query/Order.hs+1
@@ -15,5 +15,6 @@ import Rel8.Query ( Query )
1515import Rel8.Query.Opaleye ( mapOpaleye )
1616
1717
18+-- | Order the rows returned by a query.
1819orderBy :: Order a -> Query a -> Query a
1920orderBy (Order o) = mapOpaleye (Opaleye.orderBy o)
src/Rel8/Query/Rebind.hsnew file+27
@@ -0,0 +1,27 @@
1+{-# language FlexibleContexts #-}
2+
3+module Rel8.Query.Rebind
4+ ( rebind
5+ )
6+where
7+
8+-- base
9+import Prelude
10+import Control.Arrow ((<<<))
11+
12+-- opaleye
13+import qualified Opaleye.Internal.Rebind as Opaleye
14+
15+-- rel8
16+import Rel8.Expr ( Expr )
17+import Rel8.Query ( Query )
18+import Rel8.Table ( Table )
19+import Rel8.Table.Opaleye ( unpackspec )
20+import Rel8.Query.Opaleye (fromOpaleye)
21+
22+
23+-- | 'rebind' takes a variable name, some expressions, and binds each of them
24+-- to a new variable in the SQL. The @a@ returned consists only of these
25+-- variables. It's essentially a @let@ binding for Postgres expressions.
26+rebind :: Table Expr a => String -> a -> Query a
27+rebind prefix a = fromOpaleye (Opaleye.rebindExplicitPrefix prefix unpackspec <<< pure a)
src/Rel8/Query/SQL.hs+7−58
@@ -1,72 +1,21 @@
11{-# language FlexibleContexts #-}
2−{-# language TypeFamilies #-}
3−{-# language ViewPatterns #-}
2+{-# language MonoLocalBinds #-}
43
54module Rel8.Query.SQL
65 ( showQuery
7− , sqlForQuery, sqlForQueryWithNames
86 )
97where
108
119-- base
12−import Data.Foldable ( fold )
13−import Data.Functor.Const ( Const( Const ), getConst )
14−import Data.Void ( Void )
1510import Prelude
1611
17−-- opaleye
18−import qualified Opaleye.Internal.HaskellDB.Sql as Opaleye
19−import qualified Opaleye.Internal.PrimQuery as Opaleye
20−import qualified Opaleye.Internal.Print as Opaleye
21−import qualified Opaleye.Internal.Optimize as Opaleye
22−import qualified Opaleye.Internal.QueryArr as Opaleye hiding ( Select )
23−import qualified Opaleye.Internal.Sql as Opaleye
24−
2512-- rel8
26−import Rel8.Expr.Opaleye ( toPrimExpr )
13+import Rel8.Expr ( Expr )
2714import Rel8.Query ( Query )
28−import Rel8.Query.Opaleye ( toOpaleye )
29−import qualified Rel8.Query.Optimize as Rel8 ( optimize )
30−import Rel8.Schema.Context ( DB( DB ), Name( Name ) )
31−import Rel8.Schema.HTable ( htabulateA, hfield )
32−import Rel8.Table ( Table, toColumns )
33−import Rel8.Table.Name ( namesFromLabels )
34−import Rel8.Table.Recontextualize ( Selects )
35−
36−
37−showQuery :: Table DB a => Query a -> String
38−showQuery = fold . sqlForQuery
39−
40−
41−sqlForQuery :: Table DB a
42− => Query a -> Maybe String
43−sqlForQuery = sqlForQueryWithNames namesFromLabels . fmap toColumns
44−
45−
46−sqlForQueryWithNames :: Selects names exprs
47− => names -> Query exprs -> Maybe String
48−sqlForQueryWithNames names query =
49− show . Opaleye.ppSql . selectFrom names exprs <$> optimize primQuery
50− where
51− (exprs, primQuery, _) =
52− Opaleye.runSimpleQueryArrStart (toOpaleye query) ()
53−
54−
55−optimize :: Opaleye.PrimQuery' a -> Maybe (Opaleye.PrimQuery' Void)
56−optimize = Opaleye.removeEmpty . Rel8.optimize . Opaleye.optimize
15+import Rel8.Statement.Select ( ppSelect )
16+import Rel8.Table ( Table )
5717
5818
59−selectFrom :: Selects names exprs
60− => names -> exprs -> Opaleye.PrimQuery' Void -> Opaleye.Select
61−selectFrom (toColumns -> names) (toColumns -> exprs) query =
62− Opaleye.SelectFrom $ Opaleye.newSelect
63− { Opaleye.attrs = Opaleye.SelectAttrs attributes
64− , Opaleye.tables = Opaleye.oneTable select
65− }
66− where
67− select = Opaleye.foldPrimQuery Opaleye.sqlQueryGenerator query
68− attributes = getConst $ htabulateA $ \field -> case hfield names field of
69− Name name -> case hfield exprs field of
70− DB (toPrimExpr -> expr) -> Const (pure (makeAttr name expr))
71− makeAttr label expr =
72− (Opaleye.sqlExpr expr, Just (Opaleye.SqlColumn label))
19+-- | Convert a 'Query' to a 'String' containing a @SELECT@ statement.
20+showQuery :: Table Expr a => Query a -> String
21+showQuery = show . ppSelect
src/Rel8/Query/Set.hs+16−4
@@ -14,33 +14,45 @@ import Prelude ()
1414import qualified Opaleye.Binary as Opaleye
1515
1616-- rel8
17+import Rel8.Expr ( Expr )
1718import {-# SOURCE #-} Rel8.Query ( Query )
1819import Rel8.Query.Opaleye ( zipOpaleyeWith )
1920import Rel8.Table ( Table )
2021import Rel8.Table.Eq ( EqTable )
2122import Rel8.Table.Opaleye ( binaryspec )
22−import Rel8.Schema.Context ( DB )
2323
2424
25+-- | Combine the results of two queries of the same type, collapsing
26+-- duplicates. @union a b@ is the same as the SQL statement @a UNION b@.
2527union :: EqTable a => Query a -> Query a -> Query a
2628union = zipOpaleyeWith (Opaleye.unionExplicit binaryspec)
2729
2830
29−unionAll :: Table DB a => Query a -> Query a -> Query a
31+-- | Combine the results of two queries of the same type, retaining duplicates.
32+-- @unionAll a b@ is the same as the SQL statement @a UNION ALL b@.
33+unionAll :: Table Expr a => Query a -> Query a -> Query a
3034unionAll = zipOpaleyeWith (Opaleye.unionAllExplicit binaryspec)
3135
3236
37+-- | Find the intersection of two queries, collapsing duplicates. @intersect a
38+-- b@ is the same as the SQL statement @a INTERSECT b@.
3339intersect :: EqTable a => Query a -> Query a -> Query a
3440intersect = zipOpaleyeWith (Opaleye.intersectExplicit binaryspec)
3541
3642
37−intersectAll :: Table DB a => Query a -> Query a -> Query a
43+-- | Find the intersection of two queries, retaining duplicates. @intersectAll
44+-- a b@ is the same as the SQL statement @a INTERSECT ALL b@.
45+intersectAll :: EqTable a => Query a -> Query a -> Query a
3846intersectAll = zipOpaleyeWith (Opaleye.intersectAllExplicit binaryspec)
3947
4048
49+-- | Find the difference of two queries, collapsing duplicates @except a b@ is
50+-- the same as the SQL statement @a EXCEPT b@.
4151except :: EqTable a => Query a -> Query a -> Query a
4252except = zipOpaleyeWith (Opaleye.exceptExplicit binaryspec)
4353
4454
45−exceptAll :: Table DB a => Query a -> Query a -> Query a
55+-- | Find the difference of two queries, retaining duplicates. @exceptAll a b@
56+-- is the same as the SQL statement @a EXCEPT ALL b@.
57+exceptAll :: EqTable a => Query a -> Query a -> Query a
4658exceptAll = zipOpaleyeWith (Opaleye.exceptAllExplicit binaryspec)
src/Rel8/Query/These.hs+63−54
@@ -1,4 +1,5 @@
11{-# language FlexibleContexts #-}
2+{-# language GADTs #-}
23
34module Rel8.Query.These
45 ( alignBy
@@ -7,100 +8,116 @@ module Rel8.Query.These
78 , keepThisTable, loseThisTable
89 , keepThatTable, loseThatTable
910 , keepThoseTable, loseThoseTable
10− , bindTheseTable
1111 , bitraverseTheseTable
1212 )
1313where
1414
1515-- base
16−import Data.Bifunctor ( bimap )
1716import Prelude
1817
18+-- comonad
19+import Control.Comonad ( extract )
20+
1921-- opaleye
20−import qualified Opaleye.Internal.Join as Opaleye
22+import qualified Opaleye.Internal.PackMap as Opaleye
2123import qualified Opaleye.Internal.PrimQuery as Opaleye
24+import qualified Opaleye.Internal.QueryArr as Opaleye
25+import qualified Opaleye.Internal.Tag as Opaleye
2226
2327-- rel8
2428import Rel8.Expr ( Expr )
25−import Rel8.Expr.Bool ( (&&.), boolExpr, not_ )
26−import Rel8.Expr.Opaleye ( toColumn, toPrimExpr )
29+import Rel8.Expr.Bool ( boolExpr, not_ )
30+import Rel8.Expr.Eq ( (==.) )
31+import Rel8.Expr.Opaleye ( toPrimExpr, traversePrimExpr )
2732import Rel8.Expr.Serialize ( litExpr )
2833import Rel8.Query ( Query )
2934import Rel8.Query.Filter ( where_ )
30−import Rel8.Query.Maybe ( traverseMaybeTable )
35+import Rel8.Query.Maybe ( optional )
3136import Rel8.Query.Opaleye ( zipOpaleyeWith )
32−import Rel8.Schema.Context ( DB )
33−import Rel8.Table ( Table )
3437import Rel8.Table.Either ( EitherTable( EitherTable ) )
3538import Rel8.Table.Maybe ( MaybeTable( MaybeTable ), isJustTable )
36−import Rel8.Table.Opaleye ( unpackspec )
3739import Rel8.Table.These
38− ( TheseTable( TheseTable )
40+ ( TheseTable( TheseTable, here, there )
41+ , hasHereTable, hasThereTable
3942 , isThisTable, isThatTable, isThoseTable
4043 )
4144import Rel8.Type.Tag ( EitherTag( IsLeft, IsRight ) )
4245
4346
44−alignBy :: (Table DB a, Table DB b)
47+-- | Corresponds to a @FULL OUTER JOIN@ between two queries.
48+alignBy :: ()
4549 => (a -> b -> Expr Bool)
46− -> Query a -> Query b -> Query (TheseTable a b)
47−alignBy condition as bs =
48− uncurry TheseTable <$> zipOpaleyeWith fullOuterJoin as bs
49− where
50− fullOuterJoin a b =
51− Opaleye.joinExplicit unpackspec unpackspec pure pure full a b on
52− where
53− full = Opaleye.FullJoin
54− on = toColumn . toPrimExpr . uncurry condition
55−
56−
57−keepHereTable :: TheseTable a b -> Query (a, MaybeTable b)
50+ -> Query a -> Query b -> Query (TheseTable Expr a b)
51+alignBy condition = zipOpaleyeWith $ \left right -> Opaleye.stateQueryArr $ \_ t -> case t of
52+ tag -> (tab, join', tag''')
53+ where
54+ (ma, left', tag') = Opaleye.runStateQueryArr (pure <$> left) () tag
55+ (mb, right', tag'') = Opaleye.runStateQueryArr (pure <$> right) () tag'
56+ MaybeTable hasHere a = ma
57+ MaybeTable hasThere b = mb
58+ (hasHere', lbindings) = Opaleye.run $ do
59+ traversePrimExpr (Opaleye.extractAttr "hasHere" tag'') hasHere
60+ (hasThere', rbindings) = Opaleye.run $ do
61+ traversePrimExpr (Opaleye.extractAttr "hasThere" tag'') hasThere
62+ tag''' = Opaleye.next tag''
63+ join = Opaleye.Join Opaleye.FullJoin on left'' right''
64+ where
65+ on = toPrimExpr $ condition (extract a) (extract b)
66+ left'' = (Opaleye.NonLateral, Opaleye.toPrimQuery (left' <> Opaleye.aRebind lbindings))
67+ right'' = (Opaleye.NonLateral, Opaleye.toPrimQuery (right' <> Opaleye.aRebind rbindings))
68+ ma' = MaybeTable hasHere' a
69+ mb' = MaybeTable hasThere' b
70+ tab = TheseTable {here = ma', there = mb'}
71+ join' = Opaleye.aProduct join
72+
73+
74+keepHereTable :: TheseTable Expr a b -> Query (a, MaybeTable Expr b)
5875keepHereTable = loseThatTable
5976
6077
61−loseHereTable :: TheseTable a b -> Query b
78+loseHereTable :: TheseTable Expr a b -> Query b
6279loseHereTable = keepThatTable
6380
6481
65−keepThereTable :: TheseTable a b -> Query (MaybeTable a, b)
82+keepThereTable :: TheseTable Expr a b -> Query (MaybeTable Expr a, b)
6683keepThereTable = loseThisTable
6784
6885
69−loseThereTable :: TheseTable a b -> Query a
86+loseThereTable :: TheseTable Expr a b -> Query a
7087loseThereTable = keepThisTable
7188
7289
73−keepThisTable :: TheseTable a b -> Query a
90+keepThisTable :: TheseTable Expr a b -> Query a
7491keepThisTable t@(TheseTable (MaybeTable _ a) _) = do
7592 where_ $ isThisTable t
76− pure a
93+ pure (extract a)
7794
7895
79−loseThisTable :: TheseTable a b -> Query (MaybeTable a, b)
96+loseThisTable :: TheseTable Expr a b -> Query (MaybeTable Expr a, b)
8097loseThisTable t@(TheseTable ma (MaybeTable _ b)) = do
8198 where_ $ not_ $ isThisTable t
82− pure (ma, b)
99+ pure (ma, extract b)
83100
84101
85−keepThatTable :: TheseTable a b -> Query b
102+keepThatTable :: TheseTable Expr a b -> Query b
86103keepThatTable t@(TheseTable _ (MaybeTable _ b)) = do
87104 where_ $ isThatTable t
88− pure b
105+ pure (extract b)
89106
90107
91−loseThatTable :: TheseTable a b -> Query (a, MaybeTable b)
108+loseThatTable :: TheseTable Expr a b -> Query (a, MaybeTable Expr b)
92109loseThatTable t@(TheseTable (MaybeTable _ a) mb) = do
93110 where_ $ not_ $ isThatTable t
94− pure (a, mb)
111+ pure (extract a, mb)
95112
96113
97−keepThoseTable :: TheseTable a b -> Query (a, b)
114+keepThoseTable :: TheseTable Expr a b -> Query (a, b)
98115keepThoseTable t@(TheseTable (MaybeTable _ a) (MaybeTable _ b)) = do
99116 where_ $ isThoseTable t
100− pure (a, b)
117+ pure (extract a, extract b)
101118
102119
103−loseThoseTable :: TheseTable a b -> Query (EitherTable a b)
120+loseThoseTable :: TheseTable Expr a b -> Query (EitherTable Expr a b)
104121loseThoseTable t@(TheseTable (MaybeTable _ a) (MaybeTable _ b)) = do
105122 where_ $ not_ $ isThoseTable t
106123 pure $ EitherTable tag a b
@@ -108,22 +125,14 @@ loseThoseTable t@(TheseTable (MaybeTable _ a) (MaybeTable _ b)) = do
108125 tag = boolExpr (litExpr IsLeft) (litExpr IsRight) (isThatTable t)
109126
110127
111−bindTheseTable :: (Table DB a, Semigroup a, Monad m)
112− => (i -> m (TheseTable a b)) -> TheseTable a i -> m (TheseTable a b)
113−bindTheseTable query (TheseTable here (MaybeTable input i)) = do
114− TheseTable here' (MaybeTable output b) <- query i
115− pure $ TheseTable (here <> here') (MaybeTable (input <> output) b)
116−
117−
118−bitraverseTheseTable :: (Table DB c, Table DB d)
128+bitraverseTheseTable :: ()
119129 => (a -> Query c)
120130 -> (b -> Query d)
121− -> TheseTable a b
122− -> Query (TheseTable c d)
123−bitraverseTheseTable f g (TheseTable here there) =
124− bimap fromJustTable fromJustTable <$>
125− alignBy (\l r -> isJustTable l &&. isJustTable r)
126− (traverseMaybeTable f here)
127− (traverseMaybeTable g there)
128− where
129− fromJustTable (MaybeTable _ a) = a
131+ -> TheseTable Expr a b
132+ -> Query (TheseTable Expr c d)
133+bitraverseTheseTable f g t = do
134+ mc <- optional (f . fst =<< keepHereTable t)
135+ md <- optional (g . snd =<< keepThereTable t)
136+ where_ $ isJustTable mc ==. hasHereTable t
137+ where_ $ isJustTable md ==. hasThereTable t
138+ pure $ TheseTable mc md
src/Rel8/Query/Values.hs+5−2
@@ -13,12 +13,15 @@ import Prelude
1313import qualified Opaleye.Values as Opaleye
1414
1515-- rel8
16+import Rel8.Expr ( Expr )
1617import {-# SOURCE #-} Rel8.Query ( Query )
1718import Rel8.Query.Opaleye ( fromOpaleye )
1819import Rel8.Table ( Table )
1920import Rel8.Table.Opaleye ( valuesspec )
20−import Rel8.Schema.Context ( DB )
2121
2222
23−values :: (Table DB a, Foldable f) => f a -> Query a
23+-- | Construct a query that returns the given input list of rows. This is like
24+-- folding a list of 'return' statements under 'Rel8.union', but uses the SQL
25+-- @VALUES@ expression for efficiency.
26+values :: (Table Expr a, Foldable f) => f a -> Query a
2427values = fromOpaleye . Opaleye.valuesExplicit valuesspec . toList
src/Rel8/Query/Window.hsnew file+26
@@ -0,0 +1,26 @@
1+module Rel8.Query.Window
2+ ( window
3+ )
4+where
5+
6+-- base
7+import Prelude ()
8+
9+-- opaleye
10+import qualified Opaleye.Window as Opaleye
11+
12+-- rel8
13+import Rel8.Query ( Query )
14+import Rel8.Query.Opaleye ( mapOpaleye )
15+import Rel8.Window ( Window( Window ) )
16+
17+
18+-- | 'window' runs a query composed of expressions containing
19+-- [window functions](https://www.postgresql.org/docs/current/tutorial-window.html).
20+-- 'window' is similar to 'Rel8.aggregate', with the main difference being
21+-- that in a window query, each input row corresponds to one output row,
22+-- whereas aggregation queries fold the entire input query down into a single
23+-- row. To put this into a Haskell context, 'Rel8.aggregate' is to 'foldl' as
24+-- 'window' is to 'scanl'.
25+window :: Window a b -> Query a -> Query b
26+window (Window a) = mapOpaleye (Opaleye.runWindows a)
src/Rel8/Schema/Column.hsdeleted−141
@@ -1,141 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language TypeFamilies #-}
3−{-# language StandaloneKindSignatures #-}
4−
5−module Rel8.Schema.Column
6− ( Column, Default, Label
7− , HEither
8− , HList
9− , HMaybe
10− , HNonEmpty
11− , HThese
12− )
13−where
14−
15−-- base
16−import Data.Kind ( Type )
17−import Data.List.NonEmpty ( NonEmpty )
18−import GHC.TypeLits ( Symbol )
19−import Prelude
20−
21−-- rel8
22−import Rel8.Kind.Labels ( Labels )
23−import Rel8.Kind.Necessity ( Necessity( Required, Optional ) )
24−import Rel8.Schema.Context ( Result, IsSpecialContext )
25−import Rel8.Schema.Field ( Field )
26−import Rel8.Schema.Nullability ( Unnullify )
27−import Rel8.Schema.Spec ( Context )
28−import Rel8.Schema.Structure
29− ( Structure
30− , Shape( Either, List, Maybe, NonEmpty, These )
31− , Shape1
32− , Shape2
33− )
34−import Rel8.Table.Either ( EitherTable )
35−import Rel8.Table.List ( ListTable )
36−import Rel8.Table.Maybe ( MaybeTable )
37−import Rel8.Table.NonEmpty ( NonEmptyTable )
38−import Rel8.Table.These ( TheseTable )
39−
40−-- these
41−import Data.These ( These )
42−
43−
44−type Label :: Symbol -> Type -> Type
45−data Label label a
46−
47−
48−type Default :: Type -> Type
49−data Default a
50−
51−
52−type GetLabel :: Type -> Labels
53−type family GetLabel a where
54− GetLabel (Label label _) = '[label]
55− GetLabel _ = '[]
56−
57−
58−type UnwrapLabel :: Type -> Type
59−type family UnwrapLabel a where
60− UnwrapLabel (Label _ a) = a
61− UnwrapLabel a = a
62−
63−
64−type GetNecessity :: Type -> Necessity
65−type family GetNecessity a where
66− GetNecessity (Default _) = 'Optional
67− GetNecessity _ = 'Required
68−
69−
70−type UnwrapDefault :: Type -> Type
71−type family UnwrapDefault a where
72− UnwrapDefault (Default a) = a
73− UnwrapDefault a = a
74−
75−
76−type Column :: Context -> Type -> Type
77−type Column context a =
78− Field context (GetLabel a)
79− (GetNecessity (UnwrapLabel a))
80− (Unnullify (UnwrapDefault (UnwrapLabel a)))
81− (UnwrapDefault (UnwrapLabel a))
82−
83−
84−type IHEither :: Bool -> Context -> Type -> Type -> Type
85−type family IHEither isSpecialContext context where
86− IHEither 'False _ = EitherTable
87− IHEither 'True Result = Either
88− IHEither 'True Structure = Shape2 'Either
89− IHEither 'True _ = EitherTable
90−
91−
92−type IHList :: Bool -> Context -> Type -> Type
93−type family IHList isSpecialContext context where
94− IHList 'False _ = ListTable
95− IHList 'True Result = []
96− IHList 'True Structure = Shape1 'List
97− IHList 'True _ = ListTable
98−
99−
100−type IHMaybe :: Bool -> Context -> Type -> Type
101−type family IHMaybe isSpecialContext context where
102− IHMaybe 'False _ = MaybeTable
103− IHMaybe 'True Result = Maybe
104− IHMaybe 'True Structure = Shape1 'Maybe
105− IHMaybe 'True _ = MaybeTable
106−
107−
108−type IHNonEmpty :: Bool -> Context -> Type -> Type
109−type family IHNonEmpty isSpecialContext context where
110− IHNonEmpty 'False _ = NonEmptyTable
111− IHNonEmpty 'True Result = NonEmpty
112− IHNonEmpty 'True Structure = Shape1 'NonEmpty
113− IHNonEmpty 'True _ = NonEmptyTable
114−
115−
116−type IHThese :: Bool -> Context -> Type -> Type -> Type
117−type family IHThese isSpecialContext context where
118− IHThese 'False _ = TheseTable
119− IHThese 'True Result = These
120− IHThese 'True Structure = Shape2 'These
121− IHThese 'True _ = TheseTable
122−
123−
124−type HEither :: Context -> Type -> Type -> Type
125−type HEither context = IHEither (IsSpecialContext context) context
126−
127−
128−type HList :: Context -> Type -> Type
129−type HList context = IHList (IsSpecialContext context) context
130−
131−
132−type HMaybe :: Context -> Type -> Type
133−type HMaybe context = IHMaybe (IsSpecialContext context) context
134−
135−
136−type HNonEmpty :: Context -> Type -> Type
137−type HNonEmpty context = IHNonEmpty (IsSpecialContext context) context
138−
139−
140−type HThese :: Context -> Type -> Type -> Type
141−type HThese context = IHThese (IsSpecialContext context) context
src/Rel8/Schema/Context.hsdeleted−144
@@ -1,144 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language DerivingStrategies #-}
3−{-# language FlexibleInstances #-}
4−{-# language GADTs #-}
5−{-# language GeneralizedNewtypeDeriving #-}
6−{-# language ScopedTypeVariables #-}
7−{-# language StandaloneDeriving #-}
8−{-# language StandaloneKindSignatures #-}
9−{-# language TypeApplications #-}
10−{-# language TypeFamilies #-}
11−{-# language UndecidableInstances #-}
12−
13−module Rel8.Schema.Context
14− ( Aggregation( Aggregation )
15− , DB( DB, unDB )
16− , Insertion( RequiredInsert, OptionalInsert )
17− , Name( Name )
18− , Result( Result )
19− , IsSpecialContext
20− )
21−where
22−
23−-- base
24−import Control.Applicative ( liftA2 )
25−import Data.String ( IsString )
26−import Prelude
27−
28−-- rel8
29−import Rel8.Aggregate ( Aggregate )
30−import Rel8.Expr ( Expr )
31−import Rel8.Kind.Necessity
32− ( Necessity( Optional, Required )
33− , SNecessity( SOptional, SRequired )
34− , KnownNecessity, necessitySing
35− )
36−import Rel8.Schema.Nullability ( Nullabilizes )
37−import Rel8.Schema.Spec ( Context, Spec( Spec ) )
38−import Rel8.Schema.Structure ( Structure )
39−import Rel8.Type.Monoid ( DBMonoid )
40−import Rel8.Type.Semigroup ( DBSemigroup )
41−
42−
43−type Aggregation :: Context
44−data Aggregation spec where
45− Aggregation :: ()
46− => Aggregate (Expr a)
47− -> Aggregation ('Spec labels necessity dbType a)
48−
49−
50−type DB :: Context
51−data DB spec where
52− DB :: ()
53− => { unDB :: Expr a }
54− -> DB ('Spec labels necessity dbType a)
55−deriving stock instance Show (DB spec)
56−
57−
58−instance
59− ( spec ~ 'Spec labels necessity dbType a
60− , DBSemigroup dbType
61− , Nullabilizes dbType a
62− ) =>
63− Semigroup (DB spec)
64− where
65− DB a <> DB b = DB (a <> b)
66−
67−
68−instance
69− ( spec ~ 'Spec labels necessity dbType a
70− , DBMonoid dbType
71− , Nullabilizes dbType a
72− ) =>
73− Monoid (DB spec)
74− where
75− mempty = DB mempty
76−
77−
78−type Insertion :: Context
79−data Insertion spec where
80− RequiredInsert :: ()
81− => Expr a
82− -> Insertion ('Spec labels 'Required dbType a)
83− OptionalInsert :: ()
84− => Maybe (Expr a)
85− -> Insertion ('Spec labels 'Optional dbType a)
86−deriving stock instance Show (Insertion spec)
87−
88−
89−instance
90− ( spec ~ 'Spec labels necessity dbType a
91− , DBSemigroup dbType
92− , Nullabilizes dbType a
93− ) =>
94− Semigroup (Insertion spec)
95− where
96− RequiredInsert a <> RequiredInsert b = RequiredInsert (a <> b)
97− OptionalInsert ma <> OptionalInsert mb = OptionalInsert (liftA2 (<>) ma mb)
98−
99−
100−instance
101− ( spec ~ 'Spec labels necessity dbType a
102− , KnownNecessity necessity
103− , DBMonoid dbType
104− , Nullabilizes dbType a
105− ) => Monoid (Insertion spec)
106− where
107− mempty = case necessitySing @necessity of
108− SRequired -> RequiredInsert mempty
109− SOptional -> OptionalInsert (Just mempty)
110−
111−
112−type Name :: Context
113−newtype Name spec = Name String
114− deriving stock Show
115− deriving newtype (IsString, Monoid, Semigroup)
116−
117−
118−type Result :: Context
119−data Result spec where
120− Result :: a -> Result ('Spec labels necessity dbType a)
121−deriving stock instance Show a =>
122− Show (Result ('Spec labels necessity dbType a))
123−
124−
125−instance (spec ~ 'Spec labels necessity dbType a, Semigroup a) =>
126− Semigroup (Result spec)
127− where
128− Result a <> Result b = Result (a <> b)
129−
130−
131−instance (spec ~ 'Spec labels necessity dbType a, Monoid a) =>
132− Monoid (Result spec)
133− where
134− mempty = Result mempty
135−
136−
137−type IsSpecialContext :: Context -> Bool
138−type family IsSpecialContext context where
139− IsSpecialContext Aggregation = 'True
140− IsSpecialContext DB = 'True
141− IsSpecialContext Insertion = 'True
142− IsSpecialContext Result = 'True
143− IsSpecialContext Structure = 'True
144− IsSpecialContext _ = 'False
src/Rel8/Schema/Context/Label.hsdeleted−67
@@ -1,67 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language LambdaCase #-}
3−{-# language FlexibleInstances #-}
4−{-# language MultiParamTypeClasses #-}
5−{-# language StandaloneKindSignatures #-}
6−{-# language TypeFamilies #-}
7−{-# language TypeOperators #-}
8−
9−module Rel8.Schema.Context.Label
10− ( Labelable( labeler, unlabeler )
11− )
12−where
13−
14−-- base
15−import Data.Kind ( Constraint )
16−import Prelude hiding ( null )
17−
18−-- rel8
19−import Rel8.Schema.Context
20− ( Aggregation( Aggregation )
21− , DB( DB )
22− , Insertion( RequiredInsert, OptionalInsert )
23− , Name( Name )
24− , Result( Result )
25− )
26−import Rel8.Schema.Spec ( Context, Spec( Spec ) )
27−
28−
29−type Labelable :: Context -> Constraint
30−class Labelable context where
31− labeler :: ()
32− => context ('Spec labels necessity db a)
33− -> context ('Spec (label ': labels) necessity db a)
34−
35− unlabeler :: ()
36− => context ('Spec (label ': labels) necessity db a)
37− -> context ('Spec labels necessity db a)
38−
39−
40−instance Labelable Aggregation where
41− labeler (Aggregation aggregate) = Aggregation aggregate
42− unlabeler (Aggregation aggregate) = Aggregation aggregate
43−
44−
45−instance Labelable DB where
46− labeler (DB a) = DB a
47− unlabeler (DB a) = DB a
48−
49−
50−instance Labelable Insertion where
51− labeler = \case
52− RequiredInsert a -> RequiredInsert a
53− OptionalInsert ma -> OptionalInsert ma
54−
55− unlabeler = \case
56− RequiredInsert a -> RequiredInsert a
57− OptionalInsert ma -> OptionalInsert ma
58−
59−
60−instance Labelable Name where
61− labeler (Name name) = Name name
62− unlabeler (Name name) = Name name
63−
64−
65−instance Labelable Result where
66− labeler (Result a) = Result a
67− unlabeler (Result a) = Result a
src/Rel8/Schema/Context/Nullify.hs+110−131
@@ -1,165 +1,144 @@
11{-# language DataKinds #-}
2−{-# language LambdaCase #-}
2+{-# language EmptyCase #-}
33{-# language FlexibleContexts #-}
4−{-# language FlexibleInstances #-}
5−{-# language MultiParamTypeClasses #-}
4+{-# language GADTs #-}
5+{-# language LambdaCase #-}
66{-# language NamedFieldPuns #-}
7−{-# language ScopedTypeVariables #-}
87{-# language StandaloneKindSignatures #-}
9−{-# language TypeApplications #-}
10−{-# language TypeFamilies #-}
118
129module Rel8.Schema.Context.Nullify
13− ( Nullifiable( encodeTag, decodeTag, nullifier, unnullifier )
14− , NullifiableEq
10+ ( Nullifiability(..), NonNullifiability(..), nullifiableOrNot, absurd
11+ , Nullifiable, nullifiability
12+ , guarder, nullifier, unnullifier
13+ , sguard, snullify
1514 )
1615where
1716
1817-- base
19−import Control.Applicative ( empty )
20−import Data.Foldable ( fold )
21−import Data.Kind ( Constraint )
22−import qualified Data.List.NonEmpty as NonEmpty
23−import Data.Monoid ( First( First ), getFirst )
18+import Data.Bool ( bool )
19+import Data.Functor.Identity ( Identity( Identity ) )
20+import Data.Kind ( Constraint, Type )
2421import Prelude hiding ( null )
2522
2623-- opaleye
2724import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
2825
2926-- rel8
30−import Rel8.Aggregate ( Aggregate, foldInputs, mapInputs )
31−import Rel8.Expr ( Expr( Expr ) )
32−import Rel8.Expr.Aggregate ( groupByExpr )
27+import Rel8.Aggregate ( Aggregate(..), zipOutputs )
28+import Rel8.Expr ( Expr )
3329import Rel8.Expr.Bool ( boolExpr )
3430import Rel8.Expr.Null ( nullify, unsafeUnnullify )
35−import Rel8.Expr.Opaleye ( fromPrimExpr, toPrimExpr )
36−import Rel8.Kind.Labels ( KnownLabels, labelsSing, renderLabels )
37−import Rel8.Kind.Necessity ( Necessity( Required ) )
38−import Rel8.Schema.Context
39− ( Aggregation( Aggregation )
40− , DB( DB )
41− , Insertion( RequiredInsert, OptionalInsert )
42− , Name( Name )
43− )
44−import Rel8.Schema.Nullability
45− ( Nullability( Nullable, NonNullable )
46− , Nullabilizes
47− )
48−import Rel8.Schema.Spec ( Context, Spec( Spec ), SSpec(..) )
49−import Rel8.Type.Eq ( DBEq )
50−import Rel8.Type.Monoid ( DBMonoid )
51−
52−
53−type Nullifiable :: Context -> Constraint
54−class Nullifiable context where
55− encodeTag :: (DBEq db, Nullabilizes db a, KnownLabels labels)
56− => Expr a
57− -> context ('Spec labels 'Required db a)
58−
59− decodeTag :: (DBMonoid db, Nullabilizes db a)
60− => context ('Spec labels 'Required db a)
61− -> Expr a
62−
63− nullifier :: ()
64− => Expr Bool
65− -> SSpec ('Spec labels necessity db a)
66− -> context ('Spec labels necessity db a)
67− -> context ('Spec labels necessity db (Maybe db))
68−
69− unnullifier :: ()
70− => Expr Bool
71− -> SSpec ('Spec labels necessity db a)
72− -> context ('Spec labels necessity db (Maybe db))
73− -> context ('Spec labels necessity db a)
74−
75−
76−instance Nullifiable Aggregation where
77− encodeTag = Aggregation . groupByExpr
78− decodeTag (Aggregation aggregate) = fold $ undoGroupBy aggregate
31+import Rel8.Expr.Opaleye ( fromPrimExpr )
32+import Rel8.Kind.Context ( SContext(..) )
33+import Rel8.Schema.Field ( Field )
34+import qualified Rel8.Schema.Kind as K
35+import Rel8.Schema.Name ( Name( Name ) )
36+import Rel8.Schema.Null ( Nullify, Nullity( Null, NotNull ) )
37+import Rel8.Schema.Result ( Result )
38+import Rel8.Schema.Spec ( Spec(..) )
7939
80− nullifier tag SSpec {nullability} (Aggregation aggregate) = Aggregation $
81− mapInputs (toPrimExpr . runTag nullability tag . fromPrimExpr) $
82− runTag nullability tag <$> aggregate
8340
84− unnullifier _ SSpec {nullability} (Aggregation aggregate) =
85− Aggregation $ unnull nullability <$> aggregate
41+type Nullifiability :: K.Context -> Type
42+data Nullifiability context where
43+ NAggregate :: Nullifiability Aggregate
44+ NExpr :: Nullifiability Expr
45+ NName :: Nullifiability Name
8646
87− {-# INLINABLE encodeTag #-}
88− {-# INLINABLE decodeTag #-}
89− {-# INLINABLE nullifier #-}
90− {-# INLINABLE unnullifier #-}
91−
92−
93−instance Nullifiable DB where
94− encodeTag = DB
95− decodeTag (DB a) = a
96− nullifier tag SSpec {nullability} (DB a) = DB $ runTag nullability tag a
97− unnullifier _ SSpec {nullability} (DB a) = DB $ unnull nullability a
98−
99− {-# INLINABLE encodeTag #-}
100− {-# INLINABLE decodeTag #-}
101− {-# INLINABLE nullifier #-}
102− {-# INLINABLE unnullifier #-}
10347
48+type Nullifiable :: K.Context -> Constraint
49+class Nullifiable context where
50+ nullifiability :: Nullifiability context
10451
105−instance Nullifiable Insertion where
106− encodeTag = RequiredInsert
107− decodeTag (RequiredInsert a) = a
10852
109− nullifier tag SSpec {nullability} = \case
110− RequiredInsert a -> RequiredInsert $ runTag nullability tag a
111− OptionalInsert ma -> OptionalInsert $ runTag nullability tag <$> ma
53+instance Nullifiable Aggregate where
54+ nullifiability = NAggregate
11255
113− unnullifier _ SSpec {nullability} = \case
114− RequiredInsert a -> RequiredInsert $ unnull nullability a
115− OptionalInsert ma -> OptionalInsert $ unnull nullability <$> ma
11656
117− {-# INLINABLE encodeTag #-}
118− {-# INLINABLE decodeTag #-}
119− {-# INLINABLE nullifier #-}
120− {-# INLINABLE unnullifier #-}
57+instance Nullifiable Expr where
58+ nullifiability = NExpr
12159
12260
12361instance Nullifiable Name where
124− encodeTag _ = nameFromLabel
125− decodeTag _ = mempty
126− nullifier _ _ (Name name) = Name name
127− unnullifier _ _ (Name name) = Name name
128−
129− {-# INLINABLE encodeTag #-}
130− {-# INLINABLE decodeTag #-}
131− {-# INLINABLE nullifier #-}
132− {-# INLINABLE unnullifier #-}
133−
134−
135−type NullifiableEq :: Context -> Context -> Constraint
136−class (a ~ b, Nullifiable b) => NullifiableEq a b
137−instance (a ~ b, Nullifiable b) => NullifiableEq a b
138−
139−
140−runTag :: Nullability db a -> Expr Bool -> Expr a -> Expr (Maybe db)
141−runTag nullability tag a = case nullability of
142− Nullable -> boolExpr null a tag
143− NonNullable -> boolExpr null (nullify a) tag
62+ nullifiability = NName
63+
64+
65+type NonNullifiability :: K.Context -> Type
66+data NonNullifiability context where
67+ NField :: NonNullifiability (Field table)
68+ NResult :: NonNullifiability Result
69+
70+
71+nullifiableOrNot :: ()
72+ => SContext context
73+ -> Either (NonNullifiability context) (Nullifiability context)
74+nullifiableOrNot = \case
75+ SAggregate -> Right NAggregate
76+ SExpr -> Right NExpr
77+ SField -> Left NField
78+ SName -> Right NName
79+ SResult -> Left NResult
80+
81+
82+absurd :: Nullifiability context -> NonNullifiability context -> a
83+absurd = \case
84+ NAggregate -> \case
85+ NExpr -> \case
86+ NName -> \case
87+
88+
89+guarder :: ()
90+ => SContext context
91+ -> context tag
92+ -> (tag -> Bool)
93+ -> (Expr tag -> Expr Bool)
94+ -> context (Maybe a)
95+ -> context (Maybe a)
96+guarder = \case
97+ SAggregate -> \tag _ isNonNull -> zipOutputs (sguard . isNonNull) tag
98+ SExpr -> \tag _ isNonNull -> sguard (isNonNull tag)
99+ SField -> \_ _ _ -> id
100+ SName -> \_ _ _ -> id
101+ SResult -> \(Identity tag) isNonNull _ (Identity a) ->
102+ Identity (bool Nothing a (isNonNull tag))
103+
104+
105+nullifier :: ()
106+ => Nullifiability context
107+ -> Spec a
108+ -> context a
109+ -> context (Nullify a)
110+nullifier = \case
111+ NAggregate -> \Spec {nullity} (Aggregate a) ->
112+ Aggregate $ snullify nullity <$> a
113+ NExpr -> \Spec {nullity} a -> snullify nullity a
114+ NName -> \_ (Name a) -> Name a
115+
116+
117+unnullifier :: ()
118+ => Nullifiability context
119+ -> Spec a
120+ -> context (Nullify a)
121+ -> context a
122+unnullifier = \case
123+ NAggregate -> \Spec {nullity} (Aggregate a) ->
124+ Aggregate $ sunnullify nullity <$> a
125+ NExpr -> \Spec {nullity} a -> sunnullify nullity a
126+ NName -> \_ (Name a) -> Name a
127+
128+
129+sguard :: Expr Bool -> Expr (Maybe a) -> Expr (Maybe a)
130+sguard condition a = boolExpr null a condition
144131 where
145− null = Expr (Opaleye.ConstExpr Opaleye.NullLit)
132+ null = fromPrimExpr $ Opaleye.ConstExpr Opaleye.NullLit
146133
147134
148−unnull :: Nullability db a -> Expr (Maybe db) -> Expr a
149−unnull nullability a = case nullability of
150− Nullable -> a
151− NonNullable -> unsafeUnnullify a
152−
153−
154−-- HACK
155−undoGroupBy :: Aggregate (Expr _a) -> Maybe (Expr a)
156−undoGroupBy = getFirst . foldInputs go
157− where
158− go Nothing a = pure (Expr a)
159− go _ _ = First empty
135+snullify :: Nullity a -> Expr a -> Expr (Nullify a)
136+snullify nullity a = case nullity of
137+ Null -> a
138+ NotNull -> nullify a
160139
161140
162−nameFromLabel :: forall labels necessity db a.
163− KnownLabels labels => Name ('Spec labels necessity db a)
164−nameFromLabel = case labelsSing @labels of
165− labels -> Name (NonEmpty.last (renderLabels labels))
141+sunnullify :: Nullity a -> Expr (Nullify a) -> Expr a
142+sunnullify nullity a = case nullity of
143+ Null -> a
144+ NotNull -> unsafeUnnullify a
src/Rel8/Schema/Context/Result.hsdeleted−198
@@ -1,198 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language DisambiguateRecordFields #-}
3−{-# language NamedFieldPuns #-}
4−{-# language TypeFamilies #-}
5−
6−module Rel8.Schema.Context.Result
7− ( fromHEitherTable, toHEitherTable
8− , fromHListTable, toHListTable
9− , fromHMaybeTable, toHMaybeTable
10− , fromHNonEmptyTable, toHNonEmptyTable
11− , fromHTheseTable, toHTheseTable
12− )
13−where
14−
15−-- base
16−import Data.Functor ( ($>) )
17−import Data.List.NonEmpty ( NonEmpty )
18−import Prelude hiding ( null )
19−
20−-- rel8
21−import Rel8.Schema.Context ( Result( Result ) )
22−import Rel8.Schema.HTable ( HTable )
23−import Rel8.Schema.HTable.Context ( H )
24−import Rel8.Schema.HTable.Either ( HEitherTable(..) )
25−import Rel8.Schema.HTable.Identity ( HIdentity(..) )
26−import Rel8.Schema.HTable.Maybe ( HMaybeTable(..) )
27−import Rel8.Schema.HTable.List ( HListTable )
28−import Rel8.Schema.HTable.NonEmpty ( HNonEmptyTable )
29−import Rel8.Schema.HTable.Nullify ( hnulls, hnullify, hunnullify )
30−import Rel8.Schema.HTable.These ( HTheseTable(..) )
31−import Rel8.Schema.HTable.Vectorize ( hvectorize, hunvectorize )
32−import Rel8.Schema.Nullability
33− ( Nullability( Nullable, NonNullable )
34− )
35−import Rel8.Schema.Spec ( Spec( Spec ), SSpec(..) )
36−import Rel8.Type.Tag ( EitherTag( IsLeft, IsRight ), MaybeTag( IsJust ) )
37−
38−-- these
39−import Data.These ( These( This, That, These ) )
40−import Data.These.Combinators ( justHere, justThere )
41−
42−
43−toHEitherTable :: (HTable t, HTable u)
44− => Either (t (H Result)) (u (H Result))
45− -> HEitherTable t u (H Result)
46−toHEitherTable = either hleft hright
47− where
48− hleft table = HEitherTable
49− { htag = HIdentity (Result IsLeft)
50− , hleft = hnullify nullifier table
51− , hright = hnulls null
52− }
53− hright table = HEitherTable
54− { htag = HIdentity (Result IsRight)
55− , hleft = hnulls null
56− , hright = hnullify nullifier table
57− }
58−{-# INLINABLE toHEitherTable #-}
59−
60−
61−fromHEitherTable :: (HTable t, HTable u)
62− => HEitherTable t u (H Result)
63− -> Either (t (H Result)) (u (H Result))
64−fromHEitherTable HEitherTable {htag, hleft, hright} = case htag of
65− HIdentity (Result tag) -> case tag of
66− IsLeft -> maybe err Left $ hunnullify unnullifier hleft
67− IsRight -> maybe err Right $ hunnullify unnullifier hright
68− where
69− err = error "fromHEitherTable: mismatch between tag and data"
70−{-# INLINABLE fromHEitherTable #-}
71−
72−
73−toHListTable :: HTable t => [t (H Result)] -> HListTable t (H Result)
74−toHListTable = hvectorize vectorizer
75−{-# INLINABLE toHListTable #-}
76−
77−
78−fromHListTable :: HTable t => HListTable t (H Result) -> [t (H Result)]
79−fromHListTable = hunvectorize unvectorizer
80−{-# INLINABLE fromHListTable #-}
81−
82−
83−toHMaybeTable :: HTable t => Maybe (t (H Result)) -> HMaybeTable t (H Result)
84−toHMaybeTable = maybe hnothing hjust
85− where
86− hnothing = HMaybeTable
87− { htag = HIdentity (Result Nothing)
88− , hjust = hnulls null
89− }
90− hjust table = HMaybeTable
91− { htag = HIdentity (Result (Just IsJust))
92− , hjust = hnullify nullifier table
93− }
94−{-# INLINABLE toHMaybeTable #-}
95−
96−
97−fromHMaybeTable :: HTable t => HMaybeTable t (H Result) -> Maybe (t (H Result))
98−fromHMaybeTable HMaybeTable {htag, hjust} = case htag of
99− HIdentity (Result tag) -> tag $>
100− case hunnullify unnullifier hjust of
101− Nothing -> error "fromHMaybeTable: mismatch between tag and data"
102− Just just -> just
103−{-# INLINABLE fromHMaybeTable #-}
104−
105−
106−toHNonEmptyTable :: HTable t => NonEmpty (t (H Result)) -> HNonEmptyTable t (H Result)
107−toHNonEmptyTable = hvectorize vectorizer
108−{-# INLINABLE toHNonEmptyTable #-}
109−
110−
111−fromHNonEmptyTable :: HTable t => HNonEmptyTable t (H Result) -> NonEmpty (t (H Result))
112−fromHNonEmptyTable = hunvectorize unvectorizer
113−{-# INLINABLE fromHNonEmptyTable #-}
114−
115−
116−toHTheseTable :: (HTable t, HTable u)
117− => These (t (H Result)) (u (H Result))
118− -> HTheseTable t u (H Result)
119−toHTheseTable tables = HTheseTable
120− { hhereTag = relabel hhereTag
121− , hhere
122− , hthereTag = relabel hthereTag
123− , hthere
124− }
125− where
126− HMaybeTable
127− { htag = hhereTag
128− , hjust = hhere
129− } = toHMaybeTable (justHere tables)
130− HMaybeTable
131− { htag = hthereTag
132− , hjust = hthere
133− } = toHMaybeTable (justThere tables)
134−{-# INLINABLE toHTheseTable #-}
135−
136−
137−fromHTheseTable :: (HTable t, HTable u)
138− => HTheseTable t u (H Result)
139− -> These (t (H Result)) (u (H Result))
140−fromHTheseTable HTheseTable {hhereTag, hhere, hthereTag, hthere} =
141− case (fromHMaybeTable mhere, fromHMaybeTable mthere) of
142− (Just a, Nothing) -> This a
143− (Nothing, Just b) -> That b
144− (Just a, Just b) -> These a b
145− _ -> error "fromHTheseTable: mismatch between tags and data"
146− where
147− mhere = HMaybeTable
148− { htag = relabel hhereTag
149− , hjust = hhere
150− }
151− mthere = HMaybeTable
152− { htag = relabel hthereTag
153− , hjust = hthere
154− }
155−{-# INLINABLE fromHTheseTable #-}
156−
157−
158−null :: Result ('Spec labels necessity db (Maybe db))
159−null = Result Nothing
160−
161−
162−nullifier :: ()
163− => SSpec ('Spec labels necessity db a)
164− -> Result ('Spec labels necessity db a)
165− -> Result ('Spec labels necessity db (Maybe db))
166−nullifier SSpec {nullability} (Result a) = Result $ case nullability of
167− Nullable -> a
168− NonNullable -> Just a
169−
170−
171−unnullifier :: ()
172− => SSpec ('Spec labels necessity db a)
173− -> Result ('Spec labels necessity db (Maybe db))
174− -> Maybe (Result ('Spec labels necessity db a))
175−unnullifier SSpec {nullability} (Result a) =
176− case nullability of
177− Nullable -> pure $ Result a
178− NonNullable -> Result <$> a
179−
180−
181−vectorizer :: Functor f
182− => SSpec ('Spec labels necessity db a)
183− -> f (Result ('Spec labels necessity db a))
184− -> Result ('Spec labels necessity (f a) (f a))
185−vectorizer _ = Result . fmap (\(Result a) -> a)
186−
187−
188−unvectorizer :: Functor f
189− => SSpec ('Spec labels necessity db a)
190− -> Result ('Spec labels necessity (f a) (f a))
191− -> f (Result ('Spec labels necessity db a))
192−unvectorizer _ (Result results) = Result <$> results
193−
194−
195−relabel :: ()
196− => HIdentity ('Spec labels necessity db a) (H Result)
197− -> HIdentity ('Spec relabels necessity db a) (H Result)
198−relabel (HIdentity (Result a)) = HIdentity (Result a)
src/Rel8/Schema/Field.hs+32−23
@@ -1,41 +1,50 @@
11{-# language DataKinds #-}
2+{-# language FlexibleContexts #-}
3+{-# language MultiParamTypeClasses #-}
24{-# language StandaloneKindSignatures #-}
35{-# language TypeFamilies #-}
4−{-# language UndecidableInstances #-}
56
67module Rel8.Schema.Field
7− ( Field
8+ ( Field(..)
9+ , fields
810 )
911where
1012
1113-- base
14+import Data.Functor.Identity ( Identity( Identity ) )
1215import Data.Kind ( Type )
1316import Prelude
1417
1518-- rel8
16−import Rel8.Aggregate ( Aggregate )
17−import Rel8.Expr ( Expr )
18−import Rel8.Kind.Labels ( Labels )
19−import Rel8.Kind.Necessity ( Necessity( Required, Optional ) )
20−import Rel8.Schema.Context
21− ( Aggregation, DB, Insertion, Result
22− , IsSpecialContext
19+import Rel8.Schema.HTable ( HField, htabulate )
20+import Rel8.Schema.HTable.Identity ( HIdentity( HIdentity ) )
21+import Rel8.Schema.Kind as K
22+import Rel8.Schema.Null ( Sql )
23+import Rel8.Table
24+ ( Table, Columns, Context, fromColumns, toColumns
25+ , FromExprs, fromResult, toResult
26+ , Transpose
2327 )
24−import Rel8.Schema.Spec ( Context, Spec( Spec ) )
25−import Rel8.Schema.Structure ( Structure, Shape( Column ), Shape1 )
28+import Rel8.Table.Transpose ( Transposes )
29+import Rel8.Type ( DBType )
2630
2731
28−type IField :: Bool -> Context -> Labels -> Necessity -> Type -> Type -> Type
29−type family IField isSpecialContext labels context necessity db a where
30− IField 'False context labels necessity db a = context ('Spec labels necessity db a)
31− IField 'True Result _labels _necessity _db a = a
32− IField 'True DB _labels _necessity _db a = Expr a
33− IField 'True Insertion _labels 'Required _db a = Expr a
34− IField 'True Insertion _labels 'Optional _db a = Maybe (Expr a)
35− IField 'True Aggregation _labels _necessity _db a = Aggregate (Expr a)
36− IField 'True Structure labels necessity db a = Shape1 'Column ('Spec labels necessity db a)
32+-- | A special context used in the construction of 'Rel8.Projection's.
33+type Field :: Type -> K.Context
34+newtype Field table a = Field (HField (Columns table) a)
3735
3836
39−type Field :: Context -> Labels -> Necessity -> Type -> Type -> Type
40−type Field context labels necessity db a =
41− IField (IsSpecialContext context) context labels necessity db a
37+instance Sql DBType a => Table (Field table) (Field table a) where
38+ type Columns (Field table a) = HIdentity a
39+ type Context (Field table a) = Field table
40+ type FromExprs (Field table a) = a
41+ type Transpose to (Field table a) = to a
42+
43+ toColumns = HIdentity
44+ fromColumns (HIdentity a) = a
45+ toResult a = HIdentity (Identity a)
46+ fromResult (HIdentity (Identity a)) = a
47+
48+
49+fields :: Transposes context (Field table) table fields => fields
50+fields = fromColumns $ htabulate Field
src/Rel8/Schema/Generic.hsdeleted−1021
@@ -1,1021 +0,0 @@
1−{-# language AllowAmbiguousTypes #-}
2−{-# language DataKinds #-}
3−{-# language DisambiguateRecordFields #-}
4−{-# language DefaultSignatures #-}
5−{-# language FlexibleContexts #-}
6−{-# language FlexibleInstances #-}
7−{-# language GADTs #-}
8−{-# language MultiParamTypeClasses #-}
9−{-# language ScopedTypeVariables #-}
10−{-# language StandaloneKindSignatures #-}
11−{-# language TypeApplications #-}
12−{-# language TypeFamilies #-}
13−{-# language TypeOperators #-}
14−{-# language UndecidableInstances #-}
15−{-# language ViewPatterns #-}
16−
17−{-# options_ghc -fno-warn-orphans #-}
18−
19−module Rel8.Schema.Generic
20− ( Rel8able
21− )
22−where
23−
24−-- base
25−import Data.Bifunctor ( bimap )
26−import Data.Kind ( Constraint, Type )
27−import Data.List.NonEmpty ( NonEmpty )
28−import GHC.Generics
29− ( Generic, Rep, from, to
30− , (:*:)( (:*:) ), K1( K1 ), M1( M1 )
31− , D, C, S
32− , Meta( MetaSel )
33− )
34−import GHC.TypeLits ( Symbol )
35−import Prelude
36−
37−-- rel8
38−import Rel8.Kind.Necessity
39− ( SNecessity( SRequired, SOptional )
40− , KnownNecessity, necessitySing
41− )
42−import Rel8.Schema.Context
43− ( Aggregation( Aggregation )
44− , DB( DB )
45− , Insertion( RequiredInsert, OptionalInsert )
46− , Result( Result )
47− , IsSpecialContext
48− )
49−import Rel8.Schema.Context.Label ( Labelable, labeler, unlabeler )
50−import Rel8.Schema.Context.Nullify ( Nullifiable )
51−import Rel8.Schema.Context.Result
52− ( fromHEitherTable, toHEitherTable
53− , fromHListTable, toHListTable
54− , fromHMaybeTable, toHMaybeTable
55− , fromHNonEmptyTable, toHNonEmptyTable
56− , fromHTheseTable, toHTheseTable
57− )
58−import Rel8.Schema.Field ( Field )
59−import Rel8.Schema.HTable ( HTable )
60−import Rel8.Schema.HTable.Context ( H, HKTable )
61−import Rel8.Schema.HTable.Either ( HEitherTable )
62−import Rel8.Schema.HTable.Identity ( HIdentity(..) )
63−import Rel8.Schema.HTable.Label ( HLabel, hlabel, hunlabel )
64−import Rel8.Schema.HTable.List ( HListTable )
65−import Rel8.Schema.HTable.Maybe ( HMaybeTable )
66−import Rel8.Schema.HTable.NonEmpty ( HNonEmptyTable )
67−import Rel8.Schema.HTable.Pair ( HPair(..) )
68−import Rel8.Schema.HTable.Quartet ( HQuartet(..) )
69−import Rel8.Schema.HTable.Quintet ( HQuintet(..) )
70−import Rel8.Schema.HTable.These ( HTheseTable )
71−import Rel8.Schema.HTable.Trio ( HTrio(..) )
72−import Rel8.Schema.HTable.Vectorize ( hrelabel )
73−import Rel8.Schema.Spec ( Spec( Spec ), KTable )
74−import qualified Rel8.Schema.Spec as Kind ( Context )
75−import Rel8.Schema.Structure
76− ( IsStructure, Shape(..), Shape1, Shape2
77− , Structure
78− )
79−import Rel8.Table
80− ( Table, Columns, Context, fromColumns, toColumns
81− )
82−import Rel8.Table.Either ( EitherTable )
83−import Rel8.Table.Lifted
84− ( fromColumns1, toColumns1
85− , fromColumns2, toColumns2
86− )
87−import Rel8.Table.List ( ListTable )
88−import Rel8.Table.Maybe ( MaybeTable(..) )
89−import Rel8.Table.NonEmpty ( NonEmptyTable )
90−import Rel8.Table.These ( TheseTable )
91−
92−-- these
93−import Data.These ( These )
94−
95−
96−instance (Rel8able t, TableHelper (IsSpecialContext context) context) =>
97− Table context (t context)
98− where
99− type Columns (t context) = GRep t
100− type Context (t context) = context
101− fromColumns = gfromColumns
102− toColumns = gtoColumns
103−
104−
105−type TableHelper :: Bool -> Kind.Context -> Constraint
106−class IsSpecialContext context ~ isSpecialContext =>
107− TableHelper isSpecialContext context
108− where
109− gfromColumns :: Rel8able t => GRep t (H context) -> t context
110− gtoColumns :: Rel8able t => t context -> GRep t (H context)
111−
112−
113−instance TableHelper 'True Aggregation where
114− gfromColumns = fromAggregationColumns
115− gtoColumns = toAggregationColumns
116−
117−
118−instance TableHelper 'True DB where
119− gfromColumns = fromDBColumns
120− gtoColumns = toDBColumns
121−
122−
123−instance TableHelper 'True Insertion where
124− gfromColumns = fromInsertionColumns
125− gtoColumns = toInsertionColumns
126−
127−
128−instance TableHelper 'True Result where
129− gfromColumns = fromResultColumns
130− gtoColumns = toResultColumns
131−
132−
133−instance (IsSpecialContext context ~ 'False, Labelable context, Nullifiable context) =>
134− TableHelper 'False context
135− where
136− gfromColumns = fromUnspecialColumns
137− gtoColumns = toUnspecialColumns
138−
139−
140−type Rel8able :: KTable -> Constraint
141−class HTable (GRep t) => Rel8able t where
142− type GRep t :: HKTable
143−
144− fromAggregationColumns :: GRep t (H Aggregation) -> t Aggregation
145− toAggregationColumns :: t Aggregation -> GRep t (H Aggregation)
146−
147− fromDBColumns :: GRep t (H DB) -> t DB
148− toDBColumns :: t DB -> GRep t (H DB)
149−
150− fromInsertionColumns :: GRep t (H Insertion) -> t Insertion
151− toInsertionColumns :: t Insertion -> GRep t (H Insertion)
152−
153− fromResultColumns :: GRep t (H Result) -> t Result
154− toResultColumns :: t Result -> GRep t (H Result)
155−
156− fromUnspecialColumns ::
157− ( IsSpecialContext context ~ 'False
158− , Labelable context, Nullifiable context
159− )
160− => GRep t (H context) -> t context
161− toUnspecialColumns ::
162− ( IsSpecialContext context ~ 'False
163− , Labelable context, Nullifiable context
164− )
165− => t context -> GRep t (H context)
166−
167− type GRep t = GColumns (Rep (t Structure))
168−
169− default fromAggregationColumns ::
170− ( Generic (t Aggregation)
171− , GColumns (Rep (t Structure)) ~ GRep t
172− , GRel8able Aggregation (Rep (t Structure)) (Rep (t Aggregation))
173− ) => GRep t (H Aggregation) -> t Aggregation
174− fromAggregationColumns = to . fromGColumns @_ @(Rep (t Structure))
175−
176− default toAggregationColumns ::
177− ( Generic (t Aggregation)
178− , GColumns (Rep (t Structure)) ~ GRep t
179− , GRel8able Aggregation (Rep (t Structure)) (Rep (t Aggregation))
180− ) => t Aggregation -> GRep t (H Aggregation)
181− toAggregationColumns = toGColumns @_ @(Rep (t Structure)) . from
182−
183− default fromDBColumns ::
184− ( Generic (t DB)
185− , GColumns (Rep (t Structure)) ~ GRep t
186− , GRel8able DB (Rep (t Structure)) (Rep (t DB))
187− ) => GRep t (H DB) -> t DB
188− fromDBColumns = to . fromGColumns @_ @(Rep (t Structure))
189−
190− default toDBColumns ::
191− ( Generic (t DB)
192− , GColumns (Rep (t Structure)) ~ GRep t
193− , GRel8able DB (Rep (t Structure)) (Rep (t DB))
194− ) => t DB -> GRep t (H DB)
195− toDBColumns = toGColumns @_ @(Rep (t Structure)) . from
196−
197− default fromInsertionColumns ::
198− ( Generic (t Insertion)
199− , GColumns (Rep (t Structure)) ~ GRep t
200− , GRel8able Insertion (Rep (t Structure)) (Rep (t Insertion))
201− ) => GRep t (H Insertion) -> t Insertion
202− fromInsertionColumns = to . fromGColumns @_ @(Rep (t Structure))
203−
204− default toInsertionColumns ::
205− ( Generic (t Insertion)
206− , GColumns (Rep (t Structure)) ~ GRep t
207− , GRel8able Insertion (Rep (t Structure)) (Rep (t Insertion))
208− ) => t Insertion -> GRep t (H Insertion)
209− toInsertionColumns = toGColumns @_ @(Rep (t Structure)) . from
210−
211− default fromResultColumns ::
212− ( Generic (t Result)
213− , GColumns (Rep (t Structure)) ~ GRep t
214− , GRel8able Result (Rep (t Structure)) (Rep (t Result))
215− ) => GRep t (H Result) -> t Result
216− fromResultColumns = to . fromGColumns @_ @(Rep (t Structure))
217−
218− default toResultColumns ::
219− ( Generic (t Result)
220− , GColumns (Rep (t Structure)) ~ GRep t
221− , GRel8able Result (Rep (t Structure)) (Rep (t Result))
222− ) => t Result -> GRep t (H Result)
223− toResultColumns = toGColumns @_ @(Rep (t Structure)) . from
224−
225− default fromUnspecialColumns ::
226− ( Generic (t context)
227− , GColumns (Rep (t Structure)) ~ GRep t
228− , GRel8able context (Rep (t Structure)) (Rep (t context))
229− ) => GRep t (H context) -> t context
230− fromUnspecialColumns = to . fromGColumns @_ @(Rep (t Structure))
231−
232− default toUnspecialColumns ::
233− ( Generic (t context)
234− , GColumns (Rep (t Structure)) ~ GRep t
235− , GRel8able context (Rep (t Structure)) (Rep (t context))
236− ) => t context -> GRep t (H context)
237− toUnspecialColumns = toGColumns @_ @(Rep (t Structure)) . from
238−
239−
240−type GColumns :: (Type -> Type) -> HKTable
241−type family GColumns structure where
242− GColumns (M1 D _ structure) = GColumns structure
243− GColumns (M1 C _ structure) = GColumns structure
244− GColumns (a :*: b) = HPair (GColumns a) (GColumns b)
245− GColumns (M1 S ('MetaSel ('Just label) _ _ _) (K1 _ structure)) =
246− K1Columns label structure
247−
248−
249−type GRel8able :: Kind.Context -> (Type -> Type) -> (Type -> Type) -> Constraint
250−class GRel8able context structure rep where
251− fromGColumns :: GColumns structure (H context) -> rep x
252− toGColumns :: rep x -> GColumns structure (H context)
253−
254−
255−instance GRel8able context structure rep => GRel8able context (M1 D c structure) (M1 D c rep) where
256− fromGColumns = M1 . fromGColumns @context @structure @rep
257− toGColumns (M1 a) = toGColumns @context @structure @rep a
258−
259−
260−instance GRel8able context structure rep => GRel8able context (M1 C c structure) (M1 C c rep) where
261− fromGColumns = M1 . fromGColumns @context @structure @rep
262− toGColumns (M1 a) = toGColumns @context @structure @rep a
263−
264−
265−instance (GRel8able context structure1 rep1, GRel8able context structure2 rep2) =>
266− GRel8able context (structure1 :*: structure2) (rep1 :*: rep2)
267− where
268− fromGColumns (HPair a b) =
269− fromGColumns @context @structure1 @rep1 a :*:
270− fromGColumns @context @structure2 @rep2 b
271− toGColumns (a :*: b) =
272− HPair
273− (toGColumns @context @structure1 @rep1 a)
274− (toGColumns @context @structure2 @rep2 b)
275−
276−
277−instance
278− ( K1Table label isSpecialContext context isStructure structure a
279− , meta ~ 'MetaSel ('Just label) _su _ss _ds
280− , structureK1 ~ K1 i structure
281− , k1 ~ K1 i a
282− ) => GRel8able context (M1 S meta structureK1) (M1 S meta k1)
283− where
284− fromGColumns = M1 . K1 . fromK1Columns @label @_ @_ @_ @structure
285− toGColumns (M1 (K1 a)) = toK1Columns @label @_ @_ @_ @structure a
286−
287−
288−type K1Columns :: Symbol -> Type -> HKTable
289−type family K1Columns label structure where
290− K1Columns label (Shape1 'Column ('Spec '[] necessity nullability blueprint)) =
291− HIdentity ('Spec '[label] necessity nullability blueprint)
292− K1Columns _label (Shape1 'Column ('Spec (label ': labels) necessity nullability blueprint)) =
293− HIdentity ('Spec (label ': labels) necessity nullability blueprint)
294− K1Columns label (Shape2 'Either a b) =
295− HLabel label (HEitherTable (K1Columns "Left" a) (K1Columns "Right" b))
296− K1Columns label (Shape1 'List a) = HListTable (K1Columns label a)
297− K1Columns label (Shape1 'Maybe a) = HLabel label (HMaybeTable (K1Columns "Just" a))
298− K1Columns label (Shape1 'NonEmpty a) = HNonEmptyTable (K1Columns label a)
299− K1Columns label (Shape2 'These a b) =
300− HLabel label (HTheseTable (K1Columns "Here" a) (K1Columns "There" b))
301− K1Columns label (a, b) =
302− HLabel label
303− (HPair
304− (K1Columns "fst" a)
305− (K1Columns "snd" b))
306− K1Columns label (a, b, c) =
307− HLabel label
308− (HTrio
309− (K1Columns "fst" a)
310− (K1Columns "snd" b)
311− (K1Columns "trd" c))
312− K1Columns label (a, b, c, d) =
313− HLabel label
314− (HQuartet
315− (K1Columns "fst" a)
316− (K1Columns "snd" b)
317− (K1Columns "trd" c)
318− (K1Columns "frt" d))
319− K1Columns label (a, b, c, d, e) =
320− HLabel label
321− (HQuintet
322− (K1Columns "fst" a)
323− (K1Columns "snd" b)
324− (K1Columns "trd" c)
325− (K1Columns "frt" d)
326− (K1Columns "fft" e))
327− K1Columns label a = HLabel label (Columns a)
328−
329−
330−type K1Table :: Symbol -> Bool -> Kind.Context -> Bool -> Type -> Type -> Constraint
331−class
332− ( isSpecialContext ~ IsSpecialContext context
333− , isStructure ~ IsStructure structure
334− ) => K1Table label isSpecialContext context isStructure structure a
335− where
336− fromK1Columns :: K1Columns label structure (H context) -> a
337− toK1Columns :: a -> K1Columns label structure (H context)
338−
339−
340−instance
341− ( x ~ Field Aggregation '[] necessity db a
342− ) => K1Table label 'True Aggregation 'True (Shape1 'Column ('Spec '[] necessity db a)) x
343− where
344− fromK1Columns (HIdentity (Aggregation a)) = a
345− toK1Columns = HIdentity . Aggregation
346− {-# INLINABLE fromK1Columns #-}
347− {-# INLINABLE toK1Columns #-}
348−
349−
350−instance
351− ( x ~ Field Aggregation (label ': labels) necessity db a
352− ) => K1Table _label 'True Aggregation 'True (Shape1 'Column ('Spec (label ': labels) necessity db a)) x
353− where
354− fromK1Columns (HIdentity (Aggregation a)) = a
355− toK1Columns = HIdentity . Aggregation
356− {-# INLINABLE fromK1Columns #-}
357− {-# INLINABLE toK1Columns #-}
358−
359−
360−instance
361− ( x ~ Field DB '[] necessity db a
362− ) => K1Table label 'True DB 'True (Shape1 'Column ('Spec '[] necessity db a)) x
363− where
364− fromK1Columns (HIdentity (DB a)) = a
365− toK1Columns = HIdentity . DB
366− {-# INLINABLE fromK1Columns #-}
367− {-# INLINABLE toK1Columns #-}
368−
369−
370−instance
371− ( x ~ Field DB (label ': labels) necessity db a
372− ) => K1Table _label 'True DB 'True (Shape1 'Column ('Spec (label ': labels) necessity db a)) x
373− where
374− fromK1Columns (HIdentity (DB a)) = a
375− toK1Columns = HIdentity . DB
376− {-# INLINABLE fromK1Columns #-}
377− {-# INLINABLE toK1Columns #-}
378−
379−
380−instance
381− ( x ~ Field Insertion '[] necessity db a
382− , KnownNecessity necessity
383− ) => K1Table label 'True Insertion 'True (Shape1 'Column ('Spec '[] necessity db a)) x
384− where
385− fromK1Columns (HIdentity insert) = case insert of
386− RequiredInsert a -> a
387− OptionalInsert ma -> ma
388− toK1Columns a = HIdentity $ case necessitySing @necessity of
389− SRequired -> RequiredInsert a
390− SOptional -> OptionalInsert a
391− {-# INLINABLE fromK1Columns #-}
392− {-# INLINABLE toK1Columns #-}
393−
394−
395−instance
396− ( x ~ Field Insertion (label ': labels) necessity db a
397− , KnownNecessity necessity
398− ) => K1Table _label 'True Insertion 'True (Shape1 'Column ('Spec (label ': labels) necessity db a)) x
399− where
400− fromK1Columns (HIdentity insert) = case insert of
401− RequiredInsert a -> a
402− OptionalInsert ma -> ma
403− toK1Columns a = HIdentity $ case necessitySing @necessity of
404− SRequired -> RequiredInsert a
405− SOptional -> OptionalInsert a
406− {-# INLINABLE fromK1Columns #-}
407− {-# INLINABLE toK1Columns #-}
408−
409−
410−instance
411− ( x ~ Field Result '[] necessity db a
412− ) => K1Table label 'True Result 'True (Shape1 'Column ('Spec '[] necessity db a)) x
413− where
414− fromK1Columns (HIdentity (Result a)) = a
415− toK1Columns = HIdentity . Result
416− {-# INLINABLE fromK1Columns #-}
417− {-# INLINABLE toK1Columns #-}
418−
419−
420−instance
421− ( x ~ Field Result (label ': labels) necessity db a
422− ) => K1Table _label 'True Result 'True (Shape1 'Column ('Spec (label ': labels) necessity db a)) x
423− where
424− fromK1Columns (HIdentity (Result a)) = a
425− toK1Columns = HIdentity . Result
426− {-# INLINABLE fromK1Columns #-}
427− {-# INLINABLE toK1Columns #-}
428−
429−
430−instance
431− ( IsSpecialContext context ~ 'False
432− , x ~ context ('Spec (label ': labels) necessity db a)
433− ) => K1Table _label 'False context 'True (Shape1 'Column ('Spec (label ': labels) necessity db a)) x
434− where
435− fromK1Columns = unHIdentity
436− toK1Columns = HIdentity
437− {-# INLINABLE fromK1Columns #-}
438− {-# INLINABLE toK1Columns #-}
439−
440−
441−instance
442− ( IsSpecialContext context ~ 'False
443− , x ~ context ('Spec '[] necessity db a)
444− , Labelable context
445− ) => K1Table label 'False context 'True (Shape1 'Column ('Spec '[] necessity db a)) x
446− where
447− fromK1Columns = unlabeler . unHIdentity
448− toK1Columns = HIdentity . labeler
449− {-# INLINABLE fromK1Columns #-}
450− {-# INLINABLE toK1Columns #-}
451−
452−
453−instance
454− ( HTable (K1Columns "Left" structure1)
455− , HTable (K1Columns "Right" structure2)
456− , K1Table "Left" 'True Aggregation (IsStructure structure1) structure1 a
457− , K1Table "Right" 'True Aggregation (IsStructure structure2) structure2 b
458− , e ~ EitherTable a b
459− ) => K1Table label 'True Aggregation 'True (Shape2 'Either structure1 structure2) e
460− where
461− fromK1Columns =
462− fromColumns2
463− (fromK1Columns @"Left" @_ @_ @_ @structure1)
464− (fromK1Columns @"Right" @_ @_ @_ @structure2) .
465− hunlabel unlabeler
466− toK1Columns =
467− hlabel labeler .
468− toColumns2
469− (toK1Columns @"Left" @_ @_ @_ @structure1)
470− (toK1Columns @"Right" @_ @_ @_ @structure2)
471− {-# INLINABLE fromK1Columns #-}
472− {-# INLINABLE toK1Columns #-}
473−
474−
475−instance
476− ( HTable (K1Columns "Left" structure1)
477− , HTable (K1Columns "Right" structure2)
478− , K1Table "Left" 'True DB (IsStructure structure1) structure1 a
479− , K1Table "Right" 'True DB (IsStructure structure2) structure2 b
480− , e ~ EitherTable a b
481− ) => K1Table label 'True DB 'True (Shape2 'Either structure1 structure2) e
482− where
483− fromK1Columns =
484− fromColumns2
485− (fromK1Columns @"Left" @_ @_ @_ @structure1)
486− (fromK1Columns @"Right" @_ @_ @_ @structure2) .
487− hunlabel unlabeler
488− toK1Columns =
489− hlabel labeler .
490− toColumns2
491− (toK1Columns @"Left" @_ @_ @_ @structure1)
492− (toK1Columns @"Right" @_ @_ @_ @structure2)
493− {-# INLINABLE fromK1Columns #-}
494− {-# INLINABLE toK1Columns #-}
495−
496−
497−instance
498− ( HTable (K1Columns "Left" structure1)
499− , HTable (K1Columns "Right" structure2)
500− , K1Table "Left" 'True Insertion (IsStructure structure1) structure1 a
501− , K1Table "Right" 'True Insertion (IsStructure structure2) structure2 b
502− , e ~ EitherTable a b
503− ) => K1Table label 'True Insertion 'True (Shape2 'Either structure1 structure2) e
504− where
505− fromK1Columns =
506− fromColumns2
507− (fromK1Columns @"Left" @_ @_ @_ @structure1)
508− (fromK1Columns @"Right" @_ @_ @_ @structure2) .
509− hunlabel unlabeler
510− toK1Columns =
511− hlabel labeler .
512− toColumns2
513− (toK1Columns @"Left" @_ @_ @_ @structure1)
514− (toK1Columns @"Right" @_ @_ @_ @structure2)
515− {-# INLINABLE fromK1Columns #-}
516− {-# INLINABLE toK1Columns #-}
517−
518−
519−instance
520− ( HTable (K1Columns "Left" structure1)
521− , HTable (K1Columns "Right" structure2)
522− , K1Table "Left" 'True Result (IsStructure structure1) structure1 a
523− , K1Table "Right" 'True Result (IsStructure structure2) structure2 b
524− , e ~ Either a b
525− ) => K1Table label 'True Result 'True (Shape2 'Either structure1 structure2) e
526− where
527− fromK1Columns
528− = bimap
529− (fromK1Columns @"Left" @_ @_ @_ @structure1)
530− (fromK1Columns @"Right" @_ @_ @_ @structure2)
531− . fromHEitherTable
532− . hunlabel unlabeler
533− toK1Columns
534− = hlabel labeler
535− . toHEitherTable
536− . bimap
537− (toK1Columns @"Left" @_ @_ @_ @structure1)
538− (toK1Columns @"Right" @_ @_ @_ @structure2)
539− {-# INLINABLE fromK1Columns #-}
540− {-# INLINABLE toK1Columns #-}
541−
542−
543−instance
544− ( HTable (K1Columns "Left" structure1)
545− , HTable (K1Columns "Right" structure2)
546− , K1Table "Left" 'False context (IsStructure structure1) structure1 a
547− , K1Table "Right" 'False context (IsStructure structure2) structure2 b
548− , IsSpecialContext context ~ 'False
549− , Labelable context
550− , Nullifiable context
551− , e ~ EitherTable a b
552− ) => K1Table label 'False context 'True (Shape2 'Either structure1 structure2) e
553− where
554− fromK1Columns =
555− fromColumns2
556− (fromK1Columns @"Left" @_ @_ @_ @structure1)
557− (fromK1Columns @"Right" @_ @_ @_ @structure2) .
558− hunlabel unlabeler
559− toK1Columns =
560− hlabel labeler .
561− toColumns2
562− (toK1Columns @"Left" @_ @_ @_ @structure1)
563− (toK1Columns @"Right" @_ @_ @_ @structure2)
564− {-# INLINABLE fromK1Columns #-}
565− {-# INLINABLE toK1Columns #-}
566−
567−
568−instance
569− ( K1Table label 'True Aggregation (IsStructure structure) structure a
570− , Table Aggregation a
571− , K1Columns label structure ~ HLabel label (Columns a)
572− , as ~ ListTable a
573− ) => K1Table label 'True Aggregation 'True (Shape1 'List structure) as
574− where
575− fromK1Columns = fromColumns . hrelabel (hunlabel unlabeler)
576− toK1Columns = hrelabel (hlabel labeler) . toColumns
577− {-# INLINABLE fromK1Columns #-}
578− {-# INLINABLE toK1Columns #-}
579−
580−
581−instance
582− ( K1Table label 'True DB (IsStructure structure) structure a
583− , Table DB a
584− , K1Columns label structure ~ HLabel label (Columns a)
585− , as ~ ListTable a
586− ) => K1Table label 'True DB 'True (Shape1 'List structure) as
587− where
588− fromK1Columns = fromColumns . hrelabel (hunlabel unlabeler)
589− toK1Columns = hrelabel (hlabel labeler) . toColumns
590− {-# INLINABLE fromK1Columns #-}
591− {-# INLINABLE toK1Columns #-}
592−
593−
594−instance
595− ( K1Table label 'True Insertion (IsStructure structure) structure a
596− , Table Insertion a
597− , K1Columns label structure ~ HLabel label (Columns a)
598− , as ~ ListTable a
599− ) => K1Table label 'True Insertion 'True (Shape1 'List structure) as
600− where
601− fromK1Columns = fromColumns . hrelabel (hunlabel unlabeler)
602− toK1Columns = hrelabel (hlabel labeler) . toColumns
603− {-# INLINABLE fromK1Columns #-}
604− {-# INLINABLE toK1Columns #-}
605−
606−
607−instance
608− ( K1Table label 'True Result (IsStructure structure) structure a
609− , HTable (K1Columns label structure)
610− , as ~ [a]
611− ) => K1Table label 'True Result 'True (Shape1 'List structure) as
612− where
613− fromK1Columns = fmap (fromK1Columns @label @'True @Result @_ @structure) . fromHListTable
614− toK1Columns = toHListTable . fmap (toK1Columns @label @'True @Result @_ @structure)
615− {-# INLINABLE fromK1Columns #-}
616− {-# INLINABLE toK1Columns #-}
617−
618−
619−instance
620− ( K1Table label 'False context (IsStructure structure) structure a
621− , IsSpecialContext context ~ 'False
622− , Table context a
623− , K1Columns label structure ~ HLabel label (Columns a)
624− , Labelable context
625− , as ~ ListTable a
626− ) => K1Table label 'False context 'True (Shape1 'List structure) as
627− where
628− fromK1Columns = fromColumns . hrelabel (hunlabel unlabeler)
629− toK1Columns = hrelabel (hlabel labeler) . toColumns
630− {-# INLINABLE fromK1Columns #-}
631− {-# INLINABLE toK1Columns #-}
632−
633−
634−instance
635− ( HTable (K1Columns "Just" structure)
636− , K1Table "Just" 'True Aggregation (IsStructure structure) structure a
637− , ma ~ MaybeTable a
638− ) => K1Table label 'True Aggregation 'True (Shape1 'Maybe structure) ma
639− where
640− fromK1Columns =
641− fromColumns1 (fromK1Columns @"Just" @_ @_ @_ @structure) .
642− hunlabel unlabeler
643− toK1Columns =
644− hlabel labeler .
645− toColumns1 (toK1Columns @"Just" @_ @_ @_ @structure)
646− {-# INLINABLE fromK1Columns #-}
647− {-# INLINABLE toK1Columns #-}
648−
649−
650−instance
651− ( HTable (K1Columns "Just" structure)
652− , K1Table "Just" 'True DB (IsStructure structure) structure a
653− , ma ~ MaybeTable a
654− ) => K1Table label 'True DB 'True (Shape1 'Maybe structure) ma
655− where
656− fromK1Columns =
657− fromColumns1 (fromK1Columns @"Just" @_ @_ @_ @structure) .
658− hunlabel unlabeler
659− toK1Columns =
660− hlabel labeler .
661− toColumns1 (toK1Columns @"Just" @_ @_ @_ @structure)
662− {-# INLINABLE fromK1Columns #-}
663− {-# INLINABLE toK1Columns #-}
664−
665−
666−instance
667− ( HTable (K1Columns "Just" structure)
668− , K1Table "Just" 'True Insertion (IsStructure structure) structure a
669− , ma ~ MaybeTable a
670− ) => K1Table label 'True Insertion 'True (Shape1 'Maybe structure) ma
671− where
672− fromK1Columns =
673− fromColumns1 (fromK1Columns @"Just" @_ @_ @_ @structure) .
674− hunlabel unlabeler
675− toK1Columns =
676− hlabel labeler .
677− toColumns1 (toK1Columns @"Just" @_ @_ @_ @structure)
678− {-# INLINABLE fromK1Columns #-}
679− {-# INLINABLE toK1Columns #-}
680−
681−
682−instance
683− ( HTable (K1Columns "Just" structure)
684− , K1Table "Just" 'True Result (IsStructure structure) structure a
685− , ma ~ Maybe a
686− ) => K1Table label 'True Result 'True (Shape1 'Maybe structure) ma
687− where
688− fromK1Columns
689− = fmap (fromK1Columns @"Just" @_ @_ @_ @structure)
690− . fromHMaybeTable
691− . hunlabel unlabeler
692− toK1Columns
693− = hlabel labeler
694− . toHMaybeTable
695− . fmap (toK1Columns @"Just" @_ @_ @_ @structure)
696− {-# INLINABLE fromK1Columns #-}
697− {-# INLINABLE toK1Columns #-}
698−
699−
700−instance
701− ( HTable (K1Columns "Just" structure)
702− , K1Table "Just" 'False context (IsStructure structure) structure a
703− , IsSpecialContext context ~ 'False
704− , Labelable context
705− , Nullifiable context
706− , ma ~ MaybeTable a
707− ) => K1Table label 'False context 'True (Shape1 'Maybe structure) ma
708− where
709− fromK1Columns =
710− fromColumns1 (fromK1Columns @"Just" @_ @_ @_ @structure) .
711− hunlabel unlabeler
712− toK1Columns =
713− hlabel labeler .
714− toColumns1 (toK1Columns @"Just" @_ @_ @_ @structure)
715− {-# INLINABLE fromK1Columns #-}
716− {-# INLINABLE toK1Columns #-}
717−
718−
719−instance
720− ( K1Table label 'True Aggregation (IsStructure structure) structure a
721− , Table Aggregation a
722− , K1Columns label structure ~ HLabel label (Columns a)
723− , as ~ NonEmptyTable a
724− ) => K1Table label 'True Aggregation 'True (Shape1 'NonEmpty structure) as
725− where
726− fromK1Columns = fromColumns . hrelabel (hunlabel unlabeler)
727− toK1Columns = hrelabel (hlabel labeler) . toColumns
728− {-# INLINABLE fromK1Columns #-}
729− {-# INLINABLE toK1Columns #-}
730−
731−
732−instance
733− ( K1Table label 'True DB (IsStructure structure) structure a
734− , Table DB a
735− , K1Columns label structure ~ HLabel label (Columns a)
736− , as ~ NonEmptyTable a
737− ) => K1Table label 'True DB 'True (Shape1 'NonEmpty structure) as
738− where
739− fromK1Columns = fromColumns . hrelabel (hunlabel unlabeler)
740− toK1Columns = hrelabel (hlabel labeler) . toColumns
741− {-# INLINABLE fromK1Columns #-}
742− {-# INLINABLE toK1Columns #-}
743−
744−
745−instance
746− ( K1Table label 'True Insertion (IsStructure structure) structure a
747− , Table Insertion a
748− , K1Columns label structure ~ HLabel label (Columns a)
749− , as ~ NonEmptyTable a
750− ) => K1Table label 'True Insertion 'True (Shape1 'NonEmpty structure) as
751− where
752− fromK1Columns = fromColumns . hrelabel (hunlabel unlabeler)
753− toK1Columns = hrelabel (hlabel labeler) . toColumns
754− {-# INLINABLE fromK1Columns #-}
755− {-# INLINABLE toK1Columns #-}
756−
757−
758−instance
759− ( K1Table label 'True Result (IsStructure structure) structure a
760− , HTable (K1Columns label structure)
761− , as ~ NonEmpty a
762− ) => K1Table label 'True Result 'True (Shape1 'NonEmpty structure) as
763− where
764− fromK1Columns = fmap (fromK1Columns @label @'True @Result @_ @structure) . fromHNonEmptyTable
765− toK1Columns = toHNonEmptyTable . fmap (toK1Columns @label @'True @Result @_ @structure)
766− {-# INLINABLE fromK1Columns #-}
767− {-# INLINABLE toK1Columns #-}
768−
769−
770−instance
771− ( K1Table label 'False context (IsStructure structure) structure a
772− , IsSpecialContext context ~ 'False
773− , Table context a
774− , K1Columns label structure ~ HLabel label (Columns a)
775− , Labelable context
776− , as ~ NonEmptyTable a
777− ) => K1Table label 'False context 'True (Shape1 'NonEmpty structure) as
778− where
779− fromK1Columns = fromColumns . hrelabel (hunlabel unlabeler)
780− toK1Columns = hrelabel (hlabel labeler) . toColumns
781− {-# INLINABLE fromK1Columns #-}
782− {-# INLINABLE toK1Columns #-}
783−
784−
785−instance
786− ( HTable (K1Columns "Here" structure1)
787− , HTable (K1Columns "There" structure2)
788− , K1Table "Here" 'True Aggregation (IsStructure structure1) structure1 a
789− , K1Table "There" 'True Aggregation (IsStructure structure2) structure2 b
790− , e ~ TheseTable a b
791− ) => K1Table label 'True Aggregation 'True (Shape2 'These structure1 structure2) e
792− where
793− fromK1Columns =
794− fromColumns2
795− (fromK1Columns @"Here" @_ @_ @_ @structure1)
796− (fromK1Columns @"There" @_ @_ @_ @structure2) .
797− hunlabel unlabeler
798− toK1Columns =
799− hlabel labeler .
800− toColumns2
801− (toK1Columns @"Here" @_ @_ @_ @structure1)
802− (toK1Columns @"There" @_ @_ @_ @structure2)
803− {-# INLINABLE fromK1Columns #-}
804− {-# INLINABLE toK1Columns #-}
805−
806−
807−instance
808− ( HTable (K1Columns "Here" structure1)
809− , HTable (K1Columns "There" structure2)
810− , K1Table "Here" 'True DB (IsStructure structure1) structure1 a
811− , K1Table "There" 'True DB (IsStructure structure2) structure2 b
812− , e ~ TheseTable a b
813− ) => K1Table label 'True DB 'True (Shape2 'These structure1 structure2) e
814− where
815− fromK1Columns =
816− fromColumns2
817− (fromK1Columns @"Here" @_ @_ @_ @structure1)
818− (fromK1Columns @"There" @_ @_ @_ @structure2) .
819− hunlabel unlabeler
820− toK1Columns =
821− hlabel labeler .
822− toColumns2
823− (toK1Columns @"Here" @_ @_ @_ @structure1)
824− (toK1Columns @"There" @_ @_ @_ @structure2)
825− {-# INLINABLE fromK1Columns #-}
826− {-# INLINABLE toK1Columns #-}
827−
828−
829−instance
830− ( HTable (K1Columns "Here" structure1)
831− , HTable (K1Columns "There" structure2)
832− , K1Table "Here" 'True Insertion (IsStructure structure1) structure1 a
833− , K1Table "There" 'True Insertion (IsStructure structure2) structure2 b
834− , e ~ TheseTable a b
835− ) => K1Table label 'True Insertion 'True (Shape2 'These structure1 structure2) e
836− where
837− fromK1Columns =
838− fromColumns2
839− (fromK1Columns @"Here" @_ @_ @_ @structure1)
840− (fromK1Columns @"There" @_ @_ @_ @structure2) .
841− hunlabel unlabeler
842− toK1Columns =
843− hlabel labeler .
844− toColumns2
845− (toK1Columns @"Here" @_ @_ @_ @structure1)
846− (toK1Columns @"There" @_ @_ @_ @structure2)
847− {-# INLINABLE fromK1Columns #-}
848− {-# INLINABLE toK1Columns #-}
849−
850−
851−instance
852− ( HTable (K1Columns "Here" structure1)
853− , HTable (K1Columns "There" structure2)
854− , K1Table "Here" 'True Result (IsStructure structure1) structure1 a
855− , K1Table "There" 'True Result (IsStructure structure2) structure2 b
856− , e ~ These a b
857− ) => K1Table label 'True Result 'True (Shape2 'These structure1 structure2) e
858− where
859− fromK1Columns
860− = bimap
861− (fromK1Columns @"Here" @_ @_ @_ @structure1)
862− (fromK1Columns @"There" @_ @_ @_ @structure2)
863− . fromHTheseTable
864− . hunlabel unlabeler
865− toK1Columns
866− = hlabel labeler
867− . toHTheseTable
868− . bimap
869− (toK1Columns @"Here" @_ @_ @_ @structure1)
870− (toK1Columns @"There" @_ @_ @_ @structure2)
871− {-# INLINABLE fromK1Columns #-}
872− {-# INLINABLE toK1Columns #-}
873−
874−
875−instance
876− ( HTable (K1Columns "Here" structure1)
877− , HTable (K1Columns "There" structure2)
878− , K1Table "Here" 'False context (IsStructure structure1) structure1 a
879− , K1Table "There" 'False context (IsStructure structure2) structure2 b
880− , IsSpecialContext context ~ 'False
881− , Labelable context
882− , Nullifiable context
883− , e ~ TheseTable a b
884− ) => K1Table label 'False context 'True (Shape2 'These structure1 structure2) e
885− where
886− fromK1Columns =
887− fromColumns2
888− (fromK1Columns @"Here" @_ @_ @_ @structure1)
889− (fromK1Columns @"There" @_ @_ @_ @structure2) .
890− hunlabel unlabeler
891− toK1Columns =
892− hlabel labeler .
893− toColumns2
894− (toK1Columns @"Here" @_ @_ @_ @structure1)
895− (toK1Columns @"There" @_ @_ @_ @structure2)
896− {-# INLINABLE fromK1Columns #-}
897− {-# INLINABLE toK1Columns #-}
898−
899−
900−
901−instance
902− ( K1Table "fst" isSpecialContext context (IsStructure structure1) structure1 a1
903− , K1Table "snd" isSpecialContext context (IsStructure structure2) structure2 a2
904− , HTable (K1Columns "fst" structure1)
905− , HTable (K1Columns "snd" structure2)
906− , Labelable context
907− , a ~ (a1, a2)
908− ) => K1Table label isSpecialContext context 'True (structure1, structure2) a
909− where
910− fromK1Columns (hunlabel unlabeler -> (HPair a b)) =
911− ( fromK1Columns @"fst" @_ @_ @_ @structure1 a
912− , fromK1Columns @"snd" @_ @_ @_ @structure2 b
913− )
914− toK1Columns (a, b) = hlabel labeler $ HPair
915− { hfst = toK1Columns @"fst" @_ @_ @_ @structure1 a
916− , hsnd = toK1Columns @"snd" @_ @_ @_ @structure2 b
917− }
918− {-# INLINABLE fromK1Columns #-}
919− {-# INLINABLE toK1Columns #-}
920−
921−
922−instance
923− ( K1Table "fst" isSpecialContext context (IsStructure structure1) structure1 a1
924− , K1Table "snd" isSpecialContext context (IsStructure structure2) structure2 a2
925− , K1Table "trd" isSpecialContext context (IsStructure structure3) structure3 a3
926− , HTable (K1Columns "fst" structure1)
927− , HTable (K1Columns "snd" structure2)
928− , HTable (K1Columns "trd" structure3)
929− , Labelable context
930− , a ~ (a1, a2, a3)
931− ) => K1Table label isSpecialContext context 'True (structure1, structure2, structure3) a
932− where
933− fromK1Columns (hunlabel unlabeler -> (HTrio a b c)) =
934− ( fromK1Columns @"fst" @_ @_ @_ @structure1 a
935− , fromK1Columns @"snd" @_ @_ @_ @structure2 b
936− , fromK1Columns @"trd" @_ @_ @_ @structure3 c
937− )
938− toK1Columns (a, b, c) = hlabel labeler $ HTrio
939− { hfst = toK1Columns @"fst" @_ @_ @_ @structure1 a
940− , hsnd = toK1Columns @"snd" @_ @_ @_ @structure2 b
941− , htrd = toK1Columns @"trd" @_ @_ @_ @structure3 c
942− }
943− {-# INLINABLE fromK1Columns #-}
944− {-# INLINABLE toK1Columns #-}
945−
946−
947−instance
948− ( K1Table "fst" isSpecialContext context (IsStructure structure1) structure1 a1
949− , K1Table "snd" isSpecialContext context (IsStructure structure2) structure2 a2
950− , K1Table "trd" isSpecialContext context (IsStructure structure3) structure3 a3
951− , K1Table "frt" isSpecialContext context (IsStructure structure3) structure4 a4
952− , HTable (K1Columns "fst" structure1)
953− , HTable (K1Columns "snd" structure2)
954− , HTable (K1Columns "trd" structure3)
955− , HTable (K1Columns "frt" structure4)
956− , Labelable context
957− , a ~ (a1, a2, a3, a4)
958− ) => K1Table label isSpecialContext context 'True (structure1, structure2, structure3, structure4) a
959− where
960− fromK1Columns (hunlabel unlabeler -> (HQuartet a b c d)) =
961− ( fromK1Columns @"fst" @_ @_ @_ @structure1 a
962− , fromK1Columns @"snd" @_ @_ @_ @structure2 b
963− , fromK1Columns @"trd" @_ @_ @_ @structure3 c
964− , fromK1Columns @"frt" @_ @_ @_ @structure4 d
965− )
966− toK1Columns (a, b, c, d) = hlabel labeler $ HQuartet
967− { hfst = toK1Columns @"fst" @_ @_ @_ @structure1 a
968− , hsnd = toK1Columns @"snd" @_ @_ @_ @structure2 b
969− , htrd = toK1Columns @"trd" @_ @_ @_ @structure3 c
970− , hfrt = toK1Columns @"frt" @_ @_ @_ @structure4 d
971− }
972− {-# INLINABLE fromK1Columns #-}
973− {-# INLINABLE toK1Columns #-}
974−
975−
976−instance
977− ( K1Table "fst" isSpecialContext context (IsStructure structure1) structure1 a1
978− , K1Table "snd" isSpecialContext context (IsStructure structure2) structure2 a2
979− , K1Table "trd" isSpecialContext context (IsStructure structure3) structure3 a3
980− , K1Table "frt" isSpecialContext context (IsStructure structure3) structure4 a4
981− , K1Table "fft" isSpecialContext context (IsStructure structure3) structure5 a5
982− , HTable (K1Columns "fst" structure1)
983− , HTable (K1Columns "snd" structure2)
984− , HTable (K1Columns "trd" structure3)
985− , HTable (K1Columns "frt" structure4)
986− , HTable (K1Columns "fft" structure5)
987− , Labelable context
988− , a ~ (a1, a2, a3, a4, a5)
989− ) => K1Table label isSpecialContext context 'True (structure1, structure2, structure3, structure4, structure5) a
990− where
991− fromK1Columns (hunlabel unlabeler -> (HQuintet a b c d e)) =
992− ( fromK1Columns @"fst" @_ @_ @_ @structure1 a
993− , fromK1Columns @"snd" @_ @_ @_ @structure2 b
994− , fromK1Columns @"trd" @_ @_ @_ @structure3 c
995− , fromK1Columns @"frt" @_ @_ @_ @structure4 d
996− , fromK1Columns @"fft" @_ @_ @_ @structure5 e
997− )
998− toK1Columns (a, b, c, d, e) = hlabel labeler $ HQuintet
999− { hfst = toK1Columns @"fst" @_ @_ @_ @structure1 a
1000− , hsnd = toK1Columns @"snd" @_ @_ @_ @structure2 b
1001− , htrd = toK1Columns @"trd" @_ @_ @_ @structure3 c
1002− , hfrt = toK1Columns @"frt" @_ @_ @_ @structure4 d
1003− , hfft = toK1Columns @"fft" @_ @_ @_ @structure5 e
1004− }
1005− {-# INLINABLE fromK1Columns #-}
1006− {-# INLINABLE toK1Columns #-}
1007−
1008−
1009−instance
1010− ( IsSpecialContext context ~ isSpecialContext
1011− , IsStructure structure ~ 'False
1012− , K1Columns label structure ~ HLabel label (Columns structure)
1013− , Columns structure ~ Columns a
1014− , Labelable context
1015− , Table context a
1016− ) => K1Table label isSpecialContext context 'False structure a
1017− where
1018− fromK1Columns = fromColumns . hunlabel unlabeler
1019− toK1Columns = hlabel labeler . toColumns
1020− {-# INLINABLE fromK1Columns #-}
1021− {-# INLINABLE toK1Columns #-}
src/Rel8/Schema/Generic/Test.hsdeleted−79
@@ -1,79 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language DeriveAnyClass #-}
3−{-# language DeriveGeneric #-}
4−{-# language DerivingStrategies #-}
5−{-# language DuplicateRecordFields #-}
6−
7−{-# options_ghc -O0 #-}
8−
9−module Rel8.Schema.Generic.Test
10− ( module Rel8.Schema.Generic.Test
11− )
12−where
13−
14−-- base
15−import GHC.Generics ( Generic )
16−import Prelude
17−
18−-- rel8
19−import Rel8.Schema.Column
20−import Rel8.Schema.Generic
21−
22−-- text
23−import Data.Text ( Text )
24−
25−
26−data Table f = Table
27− { foo :: Column f (Label "blah" Bool)
28− , bar :: Column f (Maybe Bool)
29− }
30− deriving stock Generic
31− deriving anyclass Rel8able
32−
33−
34−data TablePair f = TablePair
35− { foo :: Column f (Default Bool)
36− , bars :: (Column f Text, Column f Text)
37− }
38− deriving stock Generic
39− deriving anyclass Rel8able
40−
41−
42−data TableMaybe f = TableMaybe
43− { foo :: Column f (Label "ABC" [Maybe Bool])
44− , bars :: HMaybe f (TablePair f, TablePair f)
45− }
46− deriving stock Generic
47− deriving anyclass Rel8able
48−
49−
50−data TableEither f = TableEither
51− { foo :: Column f Bool
52− , bars :: HEither f (HMaybe f (TablePair f, TablePair f)) (Column f (Label "XYZ" Char))
53− }
54− deriving stock Generic
55− deriving anyclass Rel8able
56−
57−
58−data TableThese f = TableThese
59− { foo :: Column f Bool
60− , bars :: HThese f (TableMaybe f) (TableEither f)
61− }
62− deriving stock Generic
63− deriving anyclass Rel8able
64−
65−
66−data TableList f = TableList
67− { foo :: Column f Bool
68− , bars :: HList f (TableThese f)
69− }
70− deriving stock Generic
71− deriving anyclass Rel8able
72−
73−
74−data TableNonEmpty f = TableNonEmpty
75− { foo :: Column f Bool
76− , bars :: HNonEmpty f (TableList f)
77− }
78− deriving stock Generic
79− deriving anyclass Rel8able
src/Rel8/Schema/HTable.hs+98−63
@@ -16,13 +16,12 @@
1616module Rel8.Schema.HTable
1717 ( HTable (HField, HConstrainTable)
1818 , hfield, htabulate, htraverse, hdicts, hspecs
19− , htabulateA
20−
21− , HPair(..)
19+ , hfoldMap, hmap, htabulateA, htraverseP, htraversePWithField
2220 )
2321where
2422
2523-- base
24+import Data.Functor.Const ( Const( Const ), getConst )
2625import Data.Kind ( Constraint, Type )
2726import Data.Functor.Compose ( Compose( Compose ), getCompose )
2827import Data.Proxy ( Proxy )
@@ -34,73 +33,84 @@ import GHC.Generics
3433 )
3534import Prelude
3635
36+-- profunctors
37+import Data.Profunctor ( rmap, Profunctor (lmap) )
38+
39+-- product-profunctors
40+import Data.Profunctor.Product ( ProductProfunctor ((****)) )
41+
3742-- rel8
3843import Rel8.Schema.Dict ( Dict )
39−import Rel8.Schema.Spec ( Spec, SSpec, Context )
40−import Rel8.Schema.HTable.Context ( HKTable, H )
41−import Rel8.Schema.HTable.Pair ( HPair( HPair ) )
44+import Rel8.Schema.Spec ( Spec )
45+import Rel8.Schema.HTable.Product ( HProduct( HProduct ) )
46+import qualified Rel8.Schema.Kind as K
4247
4348-- semigroupoids
4449import Data.Functor.Apply ( Apply, (<.>) )
4550
46−
47−type HTable :: HKTable -> Constraint
51+-- | A @HTable@ is a functor-indexed/higher-kinded data type that is
52+-- representable ('htabulate'/'hfield'), constrainable ('hdicts'), and
53+-- specified ('hspecs').
54+--
55+-- This is an internal concept for Rel8, and you should not need to define
56+-- instances yourself or specify this constraint.
57+type HTable :: K.HTable -> Constraint
4858class HTable t where
49− type HField t = (field :: Context) | field -> t
50− type HConstrainTable t (c :: Spec -> Constraint) :: Constraint
59+ type HField t = (field :: Type -> Type) | field -> t
60+ type HConstrainTable t (c :: Type -> Constraint) :: Constraint
5161
52− hfield :: t (H context) -> HField t spec -> context spec
53− htabulate :: (forall spec. HField t spec -> context spec) -> t (H context)
54− htraverse :: Apply m => (forall spec. f spec -> m (g spec)) -> t (H f) -> m (t (H g))
55− hdicts :: HConstrainTable t c => t (H (Dict c))
56− hspecs :: t (H SSpec)
62+ hfield :: t context -> HField t a -> context a
63+ htabulate :: (forall a. HField t a -> context a) -> t context
64+ htraverse :: Apply m => (forall a. f a -> m (g a)) -> t f -> m (t g)
65+ hdicts :: HConstrainTable t c => t (Dict c)
66+ hspecs :: t Spec
5767
5868 type HField t = GHField t
59− type HConstrainTable t c = HConstrainTable (GHColumns (Rep (t (H Proxy)))) c
69+ type HConstrainTable t c = HConstrainTable (GHColumns (Rep (t Proxy))) c
6070
6171 default hfield ::
62− ( Generic (t (H context))
72+ ( Generic (t context)
6373 , HField t ~ GHField t
64− , HField (GHColumns (Rep (t (H Proxy)))) ~ HField (GHColumns (Rep (t (H context))))
65− , GHTable context (Rep (t (H context)))
74+ , HField (GHColumns (Rep (t Proxy))) ~ HField (GHColumns (Rep (t context)))
75+ , GHTable context (Rep (t context))
6676 )
67− => t (H context) -> HField t spec -> context spec
77+ => t context -> HField t a -> context a
6878 hfield table (GHField field) = hfield (toGHColumns (from table)) field
6979
7080 default htabulate ::
71− ( Generic (t (H context))
81+ ( Generic (t context)
7282 , HField t ~ GHField t
73− , HField (GHColumns (Rep (t (H Proxy)))) ~ HField (GHColumns (Rep (t (H context))))
74− , GHTable context (Rep (t (H context)))
83+ , HField (GHColumns (Rep (t Proxy))) ~ HField (GHColumns (Rep (t context)))
84+ , GHTable context (Rep (t context))
7585 )
76− => (forall spec. HField t spec -> context spec) -> t (H context)
86+ => (forall a. HField t a -> context a) -> t context
7787 htabulate f = to $ fromGHColumns $ htabulate (f . GHField)
7888
7989 default htraverse
8090 :: forall f g m
8191 . ( Apply m
82− , Generic (t (H f)), GHTable f (Rep (t (H f)))
83− , Generic (t (H g)), GHTable g (Rep (t (H g)))
84− , GHColumns (Rep (t (H f))) ~ GHColumns (Rep (t (H g)))
92+ , Generic (t f), GHTable f (Rep (t f))
93+ , Generic (t g), GHTable g (Rep (t g))
94+ , GHColumns (Rep (t f)) ~ GHColumns (Rep (t g))
8595 )
86− => (forall spec. f spec -> m (g spec)) -> t (H f) -> m (t (H g))
96+ => (forall a. f a -> m (g a)) -> t f -> m (t g)
8797 htraverse f = fmap (to . fromGHColumns) . htraverse f . toGHColumns . from
8898
8999 default hdicts
90100 :: forall c
91− . ( Generic (t (H (Dict c)))
92− , GHTable (Dict c) (Rep (t (H (Dict c))))
93− , GHColumns (Rep (t (H Proxy))) ~ GHColumns (Rep (t (H (Dict c))))
94− , HConstrainTable (GHColumns (Rep (t (H Proxy)))) c
101+ . ( Generic (t (Dict c))
102+ , GHTable (Dict c) (Rep (t (Dict c)))
103+ , GHColumns (Rep (t Proxy)) ~ GHColumns (Rep (t (Dict c)))
104+ , HConstrainTable (GHColumns (Rep (t Proxy))) c
95105 )
96− => t (H (Dict c))
97− hdicts = to $ fromGHColumns (hdicts @(GHColumns (Rep (t (H Proxy)))) @c)
106+ => t (Dict c)
107+ hdicts = to $ fromGHColumns (hdicts @(GHColumns (Rep (t Proxy))) @c)
98108
99109 default hspecs ::
100− ( Generic (t (H SSpec))
101− , GHTable SSpec (Rep (t (H SSpec)))
110+ ( Generic (t Spec)
111+ , GHTable Spec (Rep (t Spec))
102112 )
103− => t (H SSpec)
113+ => t Spec
104114 hspecs = to $ fromGHColumns hspecs
105115
106116 {-# INLINABLE hfield #-}
@@ -110,22 +120,47 @@ class HTable t where
110120 {-# INLINABLE hspecs #-}
111121
112122
123+hfoldMap :: (HTable t, Semigroup s)
124+ => (forall a. context a -> s) -> t context -> s
125+hfoldMap f a = getConst $ htraverse (Const . f) a
126+
127+
128+hmap :: HTable t
129+ => (forall a. context a -> context' a) -> t context -> t context'
130+hmap f a = htabulate $ \field -> f (hfield a field)
131+
132+
113133htabulateA :: (HTable t, Apply m)
114− => (forall spec. HField t spec -> m (context spec))
115− -> m (t (H context))
134+ => (forall a. HField t a -> m (context a)) -> m (t context)
116135htabulateA f = htraverse getCompose $ htabulate $ Compose . f
117136{-# INLINABLE htabulateA #-}
118137
138+newtype ApplyP p a b = ApplyP { unApplyP :: p a b }
139+
140+instance Profunctor p => Functor (ApplyP p a) where
141+ fmap f = ApplyP . rmap f . unApplyP
142+
143+instance ProductProfunctor p => Apply (ApplyP p a) where
144+ ApplyP f <.> ApplyP x = ApplyP (rmap id f **** x)
145+
146+htraverseP :: (HTable t, ProductProfunctor p)
147+ => (forall a. p (f a) (g a)) -> p (t f) (t g)
148+htraverseP f = htraversePWithField (const f)
149+
150+htraversePWithField :: (HTable t, ProductProfunctor p)
151+ => (forall a. HField t a -> p (f a) (g a)) -> p (t f) (t g)
152+htraversePWithField f = unApplyP $ htabulateA $ \field -> ApplyP $
153+ lmap (flip hfield field) (f field)
119154
120−type GHField :: HKTable -> Context
121−newtype GHField t spec = GHField (HField (GHColumns (Rep (t (H Proxy)))) spec)
155+type GHField :: K.HTable -> Type -> Type
156+newtype GHField t a = GHField (HField (GHColumns (Rep (t Proxy))) a)
122157
123158
124−type GHTable :: Context -> (Type -> Type) -> Constraint
159+type GHTable :: K.Context -> (Type -> Type) -> Constraint
125160class HTable (GHColumns rep) => GHTable context rep | rep -> context where
126− type GHColumns rep :: HKTable
127− toGHColumns :: rep x -> GHColumns rep (H context)
128− fromGHColumns :: GHColumns rep (H context) -> rep x
161+ type GHColumns rep :: K.HTable
162+ toGHColumns :: rep x -> GHColumns rep context
163+ fromGHColumns :: GHColumns rep context -> rep x
129164
130165
131166instance GHTable context rep => GHTable context (M1 i c rep) where
@@ -134,37 +169,37 @@ instance GHTable context rep => GHTable context (M1 i c rep) where
134169 fromGHColumns = M1 . fromGHColumns
135170
136171
137−instance HTable table => GHTable context (K1 i (table (H context))) where
138− type GHColumns (K1 i (table (H context))) = table
172+instance HTable table => GHTable context (K1 i (table context)) where
173+ type GHColumns (K1 i (table context)) = table
139174 toGHColumns (K1 a) = a
140175 fromGHColumns = K1
141176
142177
143178instance (GHTable context a, GHTable context b) => GHTable context (a :*: b) where
144− type GHColumns (a :*: b) = HPair (GHColumns a) (GHColumns b)
145− toGHColumns (a :*: b) = HPair (toGHColumns a) (toGHColumns b)
146− fromGHColumns (HPair a b) = fromGHColumns a :*: fromGHColumns b
179+ type GHColumns (a :*: b) = HProduct (GHColumns a) (GHColumns b)
180+ toGHColumns (a :*: b) = HProduct (toGHColumns a) (toGHColumns b)
181+ fromGHColumns (HProduct a b) = fromGHColumns a :*: fromGHColumns b
147182
148183
149−-- | A HField type for indexing into HPair.
150−type HPairField :: HKTable -> HKTable -> Context
151−data HPairField x y spec
152− = HFst (HField x spec)
153− | HSnd (HField y spec)
184+-- | A HField type for indexing into HProduct.
185+type HProductField :: K.HTable -> K.HTable -> Type -> Type
186+data HProductField x y a
187+ = HFst (HField x a)
188+ | HSnd (HField y a)
154189
155190
156−instance (HTable x, HTable y) => HTable (HPair x y) where
157− type HConstrainTable (HPair x y) c = (HConstrainTable x c, HConstrainTable y c)
158− type HField (HPair x y) = HPairField x y
191+instance (HTable x, HTable y) => HTable (HProduct x y) where
192+ type HConstrainTable (HProduct x y) c = (HConstrainTable x c, HConstrainTable y c)
193+ type HField (HProduct x y) = HProductField x y
159194
160− hfield (HPair l r) = \case
195+ hfield (HProduct l r) = \case
161196 HFst i -> hfield l i
162197 HSnd i -> hfield r i
163198
164− htabulate f = HPair (htabulate (f . HFst)) (htabulate (f . HSnd))
165− htraverse f (HPair x y) = HPair <$> htraverse f x <.> htraverse f y
166− hdicts = HPair hdicts hdicts
167− hspecs = HPair hspecs hspecs
199+ htabulate f = HProduct (htabulate (f . HFst)) (htabulate (f . HSnd))
200+ htraverse f (HProduct x y) = HProduct <$> htraverse f x <.> htraverse f y
201+ hdicts = HProduct hdicts hdicts
202+ hspecs = HProduct hspecs hspecs
168203
169204 {-# INLINABLE hfield #-}
170205 {-# INLINABLE htabulate #-}
src/Rel8/Schema/HTable/Context.hsdeleted−26
@@ -1,26 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language StandaloneKindSignatures #-}
3−
4−module Rel8.Schema.HTable.Context
5− ( HContext, H, HKTable
6− )
7−where
8−
9−-- base
10−import Data.Kind ( Type )
11−import Prelude ()
12−
13−-- rel8
14−import Rel8.Schema.Spec ( Context )
15−
16−
17−type HContext :: Type
18−newtype HContext = H Context
19−
20−
21−type H :: Context -> HContext
22−type H = 'H
23−
24−
25−type HKTable :: Type
26−type HKTable = HContext -> Type
src/Rel8/Schema/HTable/Either.hs+7−8
@@ -14,20 +14,19 @@ import GHC.Generics ( Generic )
1414import Prelude ()
1515
1616-- rel8
17−import Rel8.Kind.Necessity ( Necessity( Required ) )
1817import Rel8.Schema.HTable ( HTable )
19−import Rel8.Schema.HTable.Context ( HKTable )
20−import Rel8.Schema.HTable.Identity ( HIdentity(..) )
18+import Rel8.Schema.HTable.Identity ( HIdentity )
19+import Rel8.Schema.HTable.Label ( HLabel )
2120import Rel8.Schema.HTable.Nullify ( HNullify )
22−import Rel8.Schema.Spec ( Spec( Spec ) )
21+import qualified Rel8.Schema.Kind as K
2322import Rel8.Type.Tag ( EitherTag )
2423
2524
26−type HEitherTable :: HKTable -> HKTable -> HKTable
25+type HEitherTable :: K.HTable -> K.HTable -> K.HTable
2726data HEitherTable left right context = HEitherTable
28− { htag :: HIdentity ('Spec '["isRight"] 'Required EitherTag EitherTag) context
29− , hleft :: HNullify left context
30− , hright :: HNullify right context
27+ { htag :: HLabel "isRight" (HIdentity EitherTag) context
28+ , hleft :: HLabel "Left" (HNullify left) context
29+ , hright :: HLabel "Right" (HNullify right) context
3130 }
3231 deriving stock Generic
3332 deriving anyclass HTable
src/Rel8/Schema/HTable/Identity.hs+19−20
@@ -1,14 +1,17 @@
11{-# language DataKinds #-}
2−{-# language GADTs #-}
2+{-# language FlexibleContexts #-}
33{-# language StandaloneKindSignatures #-}
44{-# language TypeFamilies #-}
5+{-# language UndecidableInstances #-}
56
67module Rel8.Schema.HTable.Identity
7− ( HIdentity(..)
8+ ( HIdentity( HIdentity, unHIdentity )
89 )
910where
1011
1112-- base
13+import Data.Kind ( Type )
14+import Data.Type.Equality ( (:~:)( Refl ) )
1215import Prelude
1316
1417-- rel8
@@ -17,28 +20,24 @@ import Rel8.Schema.HTable
1720 ( HTable, HConstrainTable, HField
1821 , hfield, htabulate, htraverse, hdicts, hspecs
1922 )
20−import Rel8.Schema.HTable.Context ( H, HKTable )
21−import Rel8.Schema.Spec ( Context, Spec, KnownSpec, specSing )
23+import qualified Rel8.Schema.Kind as K
24+import Rel8.Schema.Null ( Sql )
25+import Rel8.Schema.Spec ( specification )
26+import Rel8.Type ( DBType )
2227
2328
24−type HIdentity :: Spec -> HKTable
25−data HIdentity spec context where
26− HIdentity ::
27− { unHIdentity :: context spec
28− } -> HIdentity spec (H context)
29+type HIdentity :: Type -> K.HTable
30+newtype HIdentity a context = HIdentity
31+ { unHIdentity :: context a
32+ }
2933
3034
31−type HIdentityField :: Spec -> Context
32−data HIdentityField _spec spec where
33− HIdentityField :: HIdentityField spec spec
35+instance Sql DBType a => HTable (HIdentity a) where
36+ type HConstrainTable (HIdentity a) constraint = constraint a
37+ type HField (HIdentity a) = (:~:) a
3438
35−
36−instance KnownSpec spec => HTable (HIdentity spec) where
37− type HConstrainTable (HIdentity spec) c = c spec
38− type HField (HIdentity spec) = HIdentityField spec
39−
40− hfield (HIdentity a) HIdentityField = a
41− htabulate f = HIdentity $ f HIdentityField
39+ hfield (HIdentity a) Refl = a
40+ htabulate f = HIdentity $ f Refl
4241 htraverse f (HIdentity a) = HIdentity <$> f a
4342 hdicts = HIdentity Dict
44− hspecs = HIdentity specSing
43+ hspecs = HIdentity specification
src/Rel8/Schema/HTable/Label.hs+33−94
@@ -1,131 +1,70 @@
1−{-# language ConstraintKinds #-}
21{-# language DataKinds #-}
3−{-# language FlexibleInstances #-}
4−{-# language GADTs #-}
5−{-# language InstanceSigs #-}
6−{-# language MultiParamTypeClasses #-}
7−{-# language QuantifiedConstraints #-}
82{-# language RankNTypes #-}
93{-# language RecordWildCards #-}
104{-# language ScopedTypeVariables #-}
115{-# language StandaloneKindSignatures #-}
126{-# language TypeApplications #-}
137{-# language TypeFamilies #-}
14−{-# language TypeOperators #-}
15−{-# language UndecidableInstances #-}
168
179module Rel8.Schema.HTable.Label
18− ( HLabel( HLabel )
19− , hlabel, hunlabel
10+ ( HLabel, hlabel, hrelabel, hunlabel
11+ , hproject
2012 )
2113where
2214
2315-- base
24−import Data.Kind ( Constraint, Type )
16+import Data.Kind ( Type )
2517import Data.Proxy ( Proxy( Proxy ) )
26−import GHC.TypeLits ( KnownSymbol, Symbol )
18+import GHC.TypeLits ( KnownSymbol, Symbol, symbolVal )
2719import Prelude
2820
2921-- rel8
30−import Rel8.Kind.Labels ( SLabels( SLabels ) )
31−import Rel8.Schema.Dict ( Dict( Dict ) )
3222import Rel8.Schema.HTable
3323 ( HTable, HConstrainTable, HField
34− , hfield, htabulate, htraverse, hdicts, hspecs
24+ , htabulate, hfield, htraverse, hdicts, hspecs
3525 )
36−import Rel8.Schema.HTable.Context ( H, HKTable )
37−import Rel8.Schema.Spec ( Context, Spec( Spec ), SSpec(..) )
26+import qualified Rel8.Schema.Kind as K
27+import Rel8.Schema.Spec ( Spec(..) )
3828
3929
40−type HLabel :: Symbol -> HKTable -> HKTable
41−data HLabel label table context where
42− HLabel :: table (H (LabelSpec label context)) -> HLabel label table (H context)
30+type HLabel :: Symbol -> K.HTable -> K.HTable
31+newtype HLabel label table context = HLabel (table context)
4332
4433
45−type HLabelField :: Symbol -> HKTable -> Context
46−data HLabelField label table spec where
47− HLabelField
48− :: HField table ('Spec labels necessity db a)
49− -> HLabelField label table ('Spec (label ': labels) necessity db a)
34+type HLabelField :: Symbol -> K.HTable -> Type -> Type
35+newtype HLabelField label table a = HLabelField (HField table a)
5036
5137
5238instance (HTable table, KnownSymbol label) => HTable (HLabel label table) where
5339 type HField (HLabel label table) = HLabelField label table
54− type HConstrainTable (HLabel label table) c =
55− HConstrainTable table (LabelSpecC label c)
56−
57− hfield (HLabel table) (HLabelField field) =
58− getLabelSpec (hfield table field)
59−
60− htabulate f = HLabel $ htabulate $ \field -> case hfield hspecs field of
61− SSpec {} -> LabelSpec (f (HLabelField field))
62− htraverse f (HLabel t) = HLabel <$> htraverse (traverseLabelSpec f) t
63−
64− hdicts :: forall c. HConstrainTable table (LabelSpecC label c)
65− => HLabel label table (H (Dict c))
66− hdicts = HLabel $ htabulate $ \field -> case hfield hspecs field of
67− SSpec {} -> case hfield (hdicts @_ @(LabelSpecC label c)) field of
68− Dict -> LabelSpec Dict
69−
70− hspecs = HLabel $ htabulate $ \field -> case hfield hspecs field of
71− SSpec {..} -> LabelSpec SSpec {labels = SLabels Proxy labels, ..}
72−
73− {-# INLINABLE hfield #-}
74− {-# INLINABLE htabulate #-}
75− {-# INLINABLE htraverse #-}
76− {-# INLINABLE hdicts #-}
40+ type HConstrainTable (HLabel label table) constraint =
41+ HConstrainTable table constraint
42+
43+ hfield (HLabel a) (HLabelField field) = hfield a field
44+ htabulate f = HLabel (htabulate (f . HLabelField))
45+ htraverse f (HLabel a) = HLabel <$> htraverse f a
46+ hdicts = HLabel (hdicts @table)
47+ hspecs = HLabel $ htabulate $ \field -> case hfield (hspecs @table) field of
48+ Spec {..} -> Spec {labels = symbolVal (Proxy @label) : labels, ..}
7749 {-# INLINABLE hspecs #-}
7850
7951
80−type LabelingSpec :: Type -> Type
81−type LabelingSpec r = Symbol -> (Spec -> r) -> Spec -> r
82−
83−
84−type LabelSpec :: LabelingSpec Type
85−data LabelSpec label context spec where
86− LabelSpec
87− :: { getLabelSpec :: context ('Spec (label ': labels) necessity db a) }
88− -> LabelSpec label context ('Spec labels necessity db a)
89−
90−
91−type LabelSpecC :: LabelingSpec Constraint
92−class
93− ( forall labels necessity db a.
94− ( spec ~ 'Spec labels necessity db a =>
95− constraint ('Spec (label ': labels) necessity db a)
96− )
97− ) => LabelSpecC label constraint spec
98−instance
99− ( spec ~ 'Spec labels necessity db a
100− , constraint ('Spec (label ': labels) necessity db a)
101− ) => LabelSpecC label constraint spec
52+hlabel :: forall label t context. t context -> HLabel label t context
53+hlabel = HLabel
54+{-# INLINABLE hlabel #-}
10255
10356
104−traverseLabelSpec :: forall context context' label spec m. Functor m
105− => (forall x. context x -> m (context' x))
106− -> LabelSpec label context spec -> m (LabelSpec label context' spec)
107−traverseLabelSpec f (LabelSpec a) = LabelSpec <$> f a
57+hrelabel :: forall label' label t context. HLabel label t context -> HLabel label' t context
58+hrelabel = hlabel . hunlabel
59+{-# INLINABLE hrelabel #-}
10860
10961
110−hlabel :: HTable t
111− => (forall labels necessity db a. ()
112− => context ('Spec labels necessity db a)
113− -> context ('Spec (label ': labels) necessity db a))
114− -> t (H context)
115− -> HLabel label t (H context)
116−hlabel labeler a = HLabel $ htabulate $ \field ->
117− case hfield hspecs field of
118− SSpec {} -> LabelSpec (labeler (hfield a field))
119−{-# INLINABLE hlabel #-}
62+hunlabel :: forall label t context. HLabel label t context -> t context
63+hunlabel (HLabel a) = a
64+{-# INLINABLE hunlabel #-}
12065
12166
122−hunlabel :: HTable t
123− => (forall labels necessity db a. ()
124− => context ('Spec (label ': labels) necessity db a)
125− -> context ('Spec labels necessity db a))
126− -> HLabel label t (H context)
127− -> t (H context)
128−hunlabel unlabler (HLabel as) =
129− htabulate $ \field -> case hfield as field of
130− LabelSpec a -> unlabler a
131−{-# INLINABLE hunlabel #-}
67+hproject :: ()
68+ => (forall ctx. t ctx -> t' ctx)
69+ -> HLabel label t context -> HLabel label t' context
70+hproject f (HLabel a) = HLabel (f a)
src/Rel8/Schema/HTable/List.hs+2−2
@@ -10,9 +10,9 @@ where
1010import Prelude ()
1111
1212-- rel8
13−import Rel8.Schema.HTable.Context ( HKTable )
13+import qualified Rel8.Schema.Kind as K
1414import Rel8.Schema.HTable.Vectorize ( HVectorize )
1515
1616
17−type HListTable :: HKTable -> HKTable
17+type HListTable :: K.HTable -> K.HTable
1818type HListTable = HVectorize []
src/Rel8/Schema/HTable/MapTable.hsnew file+99
@@ -0,0 +1,99 @@
1+{-# language AllowAmbiguousTypes #-}
2+{-# language BlockArguments #-}
3+{-# language ConstraintKinds #-}
4+{-# language DataKinds #-}
5+{-# language FlexibleInstances #-}
6+{-# language GADTs #-}
7+{-# language InstanceSigs #-}
8+{-# language MultiParamTypeClasses #-}
9+{-# language RankNTypes #-}
10+{-# language ScopedTypeVariables #-}
11+{-# language StandaloneKindSignatures #-}
12+{-# language TypeApplications #-}
13+{-# language TypeFamilies #-}
14+{-# language UndecidableInstances #-}
15+{-# language UndecidableSuperClasses #-}
16+
17+module Rel8.Schema.HTable.MapTable
18+ ( HMapTable(..)
19+ , MapSpec(..)
20+ , Precompose(..)
21+ , HMapTableField(..)
22+ , hproject
23+ )
24+where
25+
26+-- base
27+import Data.Kind ( Constraint, Type )
28+import Prelude
29+
30+-- rel8
31+import Rel8.FCF ( Exp, Eval )
32+import Rel8.Schema.HTable
33+ ( HTable, HConstrainTable, HField
34+ , hfield, htabulate, htraverse, hdicts, hspecs
35+ )
36+import Rel8.Schema.Spec ( Spec )
37+import qualified Rel8.Schema.Kind as K
38+import Rel8.Schema.Dict ( Dict( Dict ) )
39+
40+
41+type HMapTable :: (Type -> Exp Type) -> K.HTable -> K.HTable
42+newtype HMapTable f t context = HMapTable
43+ { unHMapTable :: t (Precompose f context)
44+ }
45+
46+
47+type Precompose :: (Type -> Exp Type) -> K.Context -> K.Context
48+newtype Precompose f g x = Precompose
49+ { precomposed :: g (Eval (f x))
50+ }
51+
52+
53+type HMapTableField :: (Type -> Exp Type) -> K.HTable -> K.Context
54+data HMapTableField f t x where
55+ HMapTableField :: HField t a -> HMapTableField f t (Eval (f a))
56+
57+
58+instance (HTable t, MapSpec f) => HTable (HMapTable f t) where
59+ type HField (HMapTable f t) =
60+ HMapTableField f t
61+
62+ type HConstrainTable (HMapTable f t) c =
63+ HConstrainTable t (ComposeConstraint f c)
64+
65+ hfield (HMapTable x) (HMapTableField i) =
66+ precomposed (hfield x i)
67+
68+ htabulate f =
69+ HMapTable $ htabulate (Precompose . f . HMapTableField)
70+
71+ htraverse f (HMapTable x) =
72+ HMapTable <$> htraverse (fmap Precompose . f . precomposed) x
73+ {-# INLINABLE htraverse #-}
74+
75+ hdicts :: forall c. HConstrainTable (HMapTable f t) c => HMapTable f t (Dict c)
76+ hdicts =
77+ htabulate \(HMapTableField j) ->
78+ case hfield (hdicts @_ @(ComposeConstraint f c)) j of
79+ Dict -> Dict
80+
81+ hspecs =
82+ HMapTable $ htabulate $ Precompose . mapInfo @f . hfield hspecs
83+ {-# INLINABLE hspecs #-}
84+
85+
86+type MapSpec :: (Type -> Exp Type) -> Constraint
87+class MapSpec f where
88+ mapInfo :: Spec x -> Spec (Eval (f x))
89+
90+
91+type ComposeConstraint :: (Type -> Exp Type) -> (Type -> Constraint) -> Type -> Constraint
92+class c (Eval (f a)) => ComposeConstraint f c a
93+instance c (Eval (f a)) => ComposeConstraint f c a
94+
95+
96+hproject :: ()
97+ => (forall ctx. t ctx -> t' ctx)
98+ -> HMapTable f t context -> HMapTable f t' context
99+hproject f (HMapTable a) = HMapTable (f a)
src/Rel8/Schema/HTable/Maybe.hs+6−7
@@ -14,19 +14,18 @@ import GHC.Generics ( Generic )
1414import Prelude
1515
1616-- rel8
17−import Rel8.Kind.Necessity ( Necessity( Required ) )
1817import Rel8.Schema.HTable ( HTable )
19−import Rel8.Schema.HTable.Context ( HKTable )
20−import Rel8.Schema.HTable.Identity ( HIdentity(..) )
18+import Rel8.Schema.HTable.Identity ( HIdentity )
19+import Rel8.Schema.HTable.Label ( HLabel )
2120import Rel8.Schema.HTable.Nullify ( HNullify )
22−import Rel8.Schema.Spec ( Spec( Spec ) )
21+import qualified Rel8.Schema.Kind as K
2322import Rel8.Type.Tag ( MaybeTag )
2423
2524
26−type HMaybeTable :: HKTable -> HKTable
25+type HMaybeTable :: K.HTable -> K.HTable
2726data HMaybeTable table context = HMaybeTable
28− { htag :: HIdentity ('Spec '["isJust"] 'Required MaybeTag (Maybe MaybeTag)) context
29− , hjust :: HNullify table context
27+ { htag :: HLabel "isJust" (HIdentity (Maybe MaybeTag)) context
28+ , hjust :: HLabel "Just" (HNullify table) context
3029 }
3130 deriving stock Generic
3231 deriving anyclass HTable
src/Rel8/Schema/HTable/NonEmpty.hs+2−2
@@ -11,9 +11,9 @@ import Data.List.NonEmpty ( NonEmpty )
1111import Prelude ()
1212
1313-- rel8
14−import Rel8.Schema.HTable.Context ( HKTable )
1514import Rel8.Schema.HTable.Vectorize ( HVectorize )
15+import qualified Rel8.Schema.Kind as K
1616
1717
18−type HNonEmptyTable :: HKTable -> HKTable
18+type HNonEmptyTable :: K.HTable -> K.HTable
1919type HNonEmptyTable = HVectorize NonEmpty
src/Rel8/Schema/HTable/Nullify.hs+68−97
@@ -1,146 +1,117 @@
11{-# language ConstraintKinds #-}
22{-# language DataKinds #-}
3+{-# language DeriveAnyClass #-}
4+{-# language DerivingStrategies #-}
5+{-# language DeriveGeneric #-}
36{-# language FlexibleInstances #-}
47{-# language GADTs #-}
5−{-# language InstanceSigs #-}
8+{-# language LambdaCase #-}
69{-# language MultiParamTypeClasses #-}
10+{-# language NamedFieldPuns #-}
711{-# language QuantifiedConstraints #-}
812{-# language RankNTypes #-}
913{-# language RecordWildCards #-}
1014{-# language ScopedTypeVariables #-}
1115{-# language StandaloneKindSignatures #-}
12−{-# language TypeApplications #-}
1316{-# language TypeFamilies #-}
1417{-# language UndecidableInstances #-}
1518
1619module Rel8.Schema.HTable.Nullify
1720 ( HNullify( HNullify )
18− , hnulls, hnullify, hunnullify
21+ , Nullify
22+ , hguard
23+ , hnulls
24+ , hnullify
25+ , hunnullify
26+ , hproject
1927 )
2028where
2129
2230-- base
23−import Data.Kind ( Constraint, Type )
31+import Data.Kind ( Type )
32+import GHC.Generics ( Generic )
2433import Prelude hiding ( null )
2534
2635-- rel8
27−import Rel8.Schema.Dict ( Dict( Dict ) )
28−import Rel8.Schema.HTable
29− ( HTable, HConstrainTable, HField
30− , hfield, htabulate, htabulateA, htraverse, hdicts, hspecs
36+import Rel8.FCF ( Eval, Exp )
37+import Rel8.Schema.HTable ( HTable, hfield, htabulate, htabulateA, hspecs )
38+import Rel8.Schema.HTable.MapTable
39+ ( HMapTable, HMapTableField( HMapTableField )
40+ , MapSpec, mapInfo
3141 )
32−import Rel8.Schema.HTable.Context ( H, HKTable )
33−import Rel8.Schema.Nullability ( Nullability( Nullable, NonNullable ) )
34−import Rel8.Schema.Spec ( Context, Spec( Spec ), SSpec(..) )
42+import qualified Rel8.Schema.HTable.MapTable as HMapTable ( hproject )
43+import qualified Rel8.Schema.Kind as K
44+import Rel8.Schema.Null ( Nullity( Null, NotNull ) )
45+import qualified Rel8.Schema.Null as Type ( Nullify )
46+import Rel8.Schema.Spec ( Spec(..) )
3547
3648-- semigroupoids
3749import Data.Functor.Apply ( Apply )
3850
3951
40−type HNullify :: HKTable -> HKTable
41−data HNullify table context where
42− HNullify :: table (H (NullifySpec context)) -> HNullify table (H context)
52+type HNullify :: K.HTable -> K.HTable
53+newtype HNullify table context = HNullify (HMapTable Nullify table context)
54+ deriving stock Generic
55+ deriving anyclass HTable
4356
4457
45−type HNullifyField :: HKTable -> Context
46−data HNullifyField table spec where
47− HNullifyField
48− :: HField table ('Spec labels necessity dbType a)
49− -> HNullifyField table ('Spec labels necessity dbType (Maybe dbType))
58+-- | Transform a 'Type' by allowing it to be @null@.
59+data Nullify :: Type -> Exp Type
60+type instance Eval (Nullify a) = Type.Nullify a
5061
5162
52−instance HTable table => HTable (HNullify table) where
53− type HField (HNullify table) = HNullifyField table
54− type HConstrainTable (HNullify table) c =
55− HConstrainTable table (NullifySpecC c)
63+instance MapSpec Nullify where
64+ mapInfo = \case
65+ Spec {nullity, ..} -> Spec
66+ { nullity = case nullity of
67+ Null -> Null
68+ NotNull -> Null
69+ , ..
70+ }
5671
57− hfield (HNullify table) (HNullifyField field) =
58− getNullifySpec (hfield table field)
5972
60− htabulate f = HNullify $ htabulate $ \field -> case hfield hspecs field of
61− SSpec {} -> NullifySpec (f (HNullifyField field))
62−
63− htraverse f (HNullify t) = HNullify <$> htraverse (traverseNullifySpec f) t
64−
65− hdicts :: forall c. HConstrainTable table (NullifySpecC c)
66− => HNullify table (H (Dict c))
67− hdicts = HNullify $ htabulate $ \field -> case hfield hspecs field of
68− SSpec {} -> case hfield (hdicts @_ @(NullifySpecC c)) field of
69− Dict -> NullifySpec Dict
70−
71− hspecs = HNullify $ htabulate $ \field -> case hfield hspecs field of
72− SSpec {..} -> case nullability of
73− Nullable -> NullifySpec SSpec {nullability = Nullable, ..}
74− NonNullable -> NullifySpec SSpec {nullability = Nullable, ..}
75−
76− {-# INLINABLE hfield #-}
77− {-# INLINABLE htabulate #-}
78− {-# INLINABLE htraverse #-}
79− {-# INLINABLE hdicts #-}
80− {-# INLINABLE hspecs #-}
81−
82−
83−type NullifyingSpec :: Type -> Type
84−type NullifyingSpec r = (Spec -> r) -> Spec -> r
85−
86−
87−type NullifySpec :: NullifyingSpec Type
88−data NullifySpec context spec where
89− NullifySpec
90− :: { getNullifySpec :: context ('Spec labels necessity dbType (Maybe dbType)) }
91− -> NullifySpec context ('Spec labels necessity dbType a)
92−
93−
94−type NullifySpecC :: NullifyingSpec Constraint
95−class
96− ( forall labels necessity dbType a.
97− ( spec ~ 'Spec labels necessity dbType a =>
98− constraint ('Spec labels necessity dbType (Maybe dbType))
99− )
100− ) => NullifySpecC constraint spec
101−instance
102− ( spec ~ 'Spec labels necessity dbType a
103− , constraint ('Spec labels necessity dbType (Maybe dbType))
104− ) => NullifySpecC constraint spec
105−
106−
107−traverseNullifySpec :: forall context context' spec m. Functor m
108− => (forall x. context x -> m (context' x))
109− -> NullifySpec context spec -> m (NullifySpec context' spec)
110−traverseNullifySpec f (NullifySpec a) = NullifySpec <$> f a
73+hguard :: HTable t
74+ => (forall a. context (Maybe a) -> context (Maybe a))
75+ -> HNullify t context -> HNullify t context
76+hguard guarder (HNullify as) = HNullify $ htabulate $ \(HMapTableField field) ->
77+ case hfield hspecs field of
78+ Spec {nullity} -> case hfield as (HMapTableField field) of
79+ a -> case nullity of
80+ Null -> guarder a
81+ NotNull -> guarder a
11182
11283
11384hnulls :: HTable t
114− => (forall labels necessity dbType. ()
115− => context ('Spec labels necessity dbType (Maybe dbType)))
116− -> HNullify t (H context)
117−hnulls null = HNullify $ htabulate $ \field -> case hfield hspecs field of
118− SSpec {} -> NullifySpec null
85+ => (forall a. Spec a -> context (Type.Nullify a))
86+ -> HNullify t context
87+hnulls null = HNullify $ htabulate $ \(HMapTableField field) ->
88+ case hfield hspecs field of
89+ spec@Spec {} -> null spec
11990{-# INLINABLE hnulls #-}
12091
12192
12293hnullify :: HTable t
123− => (forall labels necessity dbType a. ()
124− => SSpec ('Spec labels necessity dbType a)
125− -> context ('Spec labels necessity dbType a)
126− -> context ('Spec labels necessity dbType (Maybe dbType)))
127− -> t (H context)
128− -> HNullify t (H context)
129−hnullify nullifier a = HNullify $ htabulate $ \field ->
94+ => (forall a. Spec a -> context a -> context (Type.Nullify a))
95+ -> t context
96+ -> HNullify t context
97+hnullify nullifier a = HNullify $ htabulate $ \(HMapTableField field) ->
13098 case hfield hspecs field of
131− spec@SSpec {} -> NullifySpec (nullifier spec (hfield a field))
99+ spec@Spec {} -> nullifier spec (hfield a field)
132100{-# INLINABLE hnullify #-}
133101
134102
135103hunnullify :: (HTable t, Apply m)
136− => (forall labels necessity dbType a. ()
137− => SSpec ('Spec labels necessity dbType a)
138− -> context ('Spec labels necessity dbType (Maybe dbType))
139− -> m (context ('Spec labels necessity dbType a)))
140− -> HNullify t (H context)
141− -> m (t (H context))
104+ => (forall a. Spec a -> context (Type.Nullify a) -> m (context a))
105+ -> HNullify t context
106+ -> m (t context)
142107hunnullify unnullifier (HNullify as) =
143108 htabulateA $ \field -> case hfield hspecs field of
144− spec@SSpec {} -> case hfield as field of
145− NullifySpec a -> unnullifier spec a
109+ spec@Spec {} -> case hfield as (HMapTableField field) of
110+ a -> unnullifier spec a
146111{-# INLINABLE hunnullify #-}
112+
113+
114+hproject :: ()
115+ => (forall ctx. t ctx -> t' ctx)
116+ -> HNullify t context -> HNullify t' context
117+hproject f (HNullify a) = HNullify (HMapTable.hproject f a)
src/Rel8/Schema/HTable/Pair.hsdeleted−20
@@ -1,20 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language StandaloneKindSignatures #-}
3−
4−module Rel8.Schema.HTable.Pair
5− ( HPair(..)
6− )
7−where
8−
9−-- base
10−import Prelude ()
11−
12−-- rel8
13−import Rel8.Schema.HTable.Context ( HKTable )
14−
15−
16−type HPair :: HKTable -> HKTable -> HKTable
17−data HPair fst snd context = HPair
18− { hfst :: fst context
19− , hsnd :: snd context
20− }
src/Rel8/Schema/HTable/Product.hsnew file+17
@@ -0,0 +1,17 @@
1+{-# language DataKinds #-}
2+{-# language StandaloneKindSignatures #-}
3+
4+module Rel8.Schema.HTable.Product
5+ ( HProduct(..)
6+ )
7+where
8+
9+-- base
10+import Prelude ()
11+
12+-- rel8
13+import qualified Rel8.Schema.Kind as K
14+
15+
16+type HProduct :: K.HTable -> K.HTable -> K.HTable
17+data HProduct a b context = HProduct (a context) (b context)
src/Rel8/Schema/HTable/Quartet.hsdeleted−29
@@ -1,29 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language DeriveAnyClass #-}
3−{-# language DeriveGeneric #-}
4−{-# language DerivingStrategies #-}
5−{-# language StandaloneKindSignatures #-}
6−
7−module Rel8.Schema.HTable.Quartet
8− ( HQuartet(..)
9− )
10−where
11−
12−-- base
13−import GHC.Generics ( Generic )
14−import Prelude ()
15−
16−-- rel8
17−import Rel8.Schema.HTable ( HTable )
18−import Rel8.Schema.HTable.Context ( HKTable )
19−
20−
21−type HQuartet :: HKTable -> HKTable -> HKTable -> HKTable -> HKTable
22−data HQuartet w x y z context = HQuartet
23− { hfst :: w context
24− , hsnd :: x context
25− , htrd :: y context
26− , hfrt :: z context
27− }
28− deriving stock Generic
29− deriving anyclass HTable
src/Rel8/Schema/HTable/Quintet.hsdeleted−30
@@ -1,30 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language DeriveAnyClass #-}
3−{-# language DeriveGeneric #-}
4−{-# language DerivingStrategies #-}
5−{-# language StandaloneKindSignatures #-}
6−
7−module Rel8.Schema.HTable.Quintet
8− ( HQuintet(..)
9− )
10−where
11−
12−-- base
13−import GHC.Generics ( Generic )
14−import Prelude ()
15−
16−-- rel8
17−import Rel8.Schema.HTable ( HTable )
18−import Rel8.Schema.HTable.Context ( HKTable )
19−
20−
21−type HQuintet :: HKTable -> HKTable -> HKTable -> HKTable -> HKTable -> HKTable
22−data HQuintet v w x y z context = HQuintet
23− { hfst :: v context
24− , hsnd :: w context
25− , htrd :: x context
26− , hfrt :: y context
27− , hfft :: z context
28− }
29− deriving stock Generic
30− deriving anyclass HTable
src/Rel8/Schema/HTable/These.hs+7−8
@@ -14,21 +14,20 @@ import GHC.Generics ( Generic )
1414import Prelude
1515
1616-- rel8
17−import Rel8.Kind.Necessity ( Necessity( Required ) )
1817import Rel8.Schema.HTable ( HTable )
19−import Rel8.Schema.HTable.Context ( HKTable )
2018import Rel8.Schema.HTable.Identity ( HIdentity )
19+import Rel8.Schema.HTable.Label ( HLabel )
2120import Rel8.Schema.HTable.Nullify ( HNullify )
22−import Rel8.Schema.Spec ( Spec( Spec ) )
21+import qualified Rel8.Schema.Kind as K
2322import Rel8.Type.Tag ( MaybeTag )
2423
2524
26−type HTheseTable :: HKTable -> HKTable -> HKTable
25+type HTheseTable :: K.HTable -> K.HTable -> K.HTable
2726data HTheseTable here there context = HTheseTable
28− { hhereTag :: HIdentity ('Spec '["hasHere"] 'Required MaybeTag (Maybe MaybeTag)) context
29− , hhere :: HNullify here context
30− , hthereTag :: HIdentity ('Spec '["hasThere"] 'Required MaybeTag (Maybe MaybeTag)) context
31− , hthere :: HNullify there context
27+ { hhereTag :: HLabel "hereTag" (HIdentity (Maybe MaybeTag)) context
28+ , hhere :: HLabel "Here" (HNullify here) context
29+ , hthereTag :: HLabel "thereTag" (HIdentity (Maybe MaybeTag)) context
30+ , hthere :: HLabel "There" (HNullify there) context
3231 }
3332 deriving stock Generic
3433 deriving anyclass HTable
src/Rel8/Schema/HTable/Trio.hsdeleted−28
@@ -1,28 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language DeriveAnyClass #-}
3−{-# language DeriveGeneric #-}
4−{-# language DerivingStrategies #-}
5−{-# language StandaloneKindSignatures #-}
6−
7−module Rel8.Schema.HTable.Trio
8− ( HTrio(..)
9− )
10−where
11−
12−-- base
13−import GHC.Generics ( Generic )
14−import Prelude ()
15−
16−-- rel8
17−import Rel8.Schema.HTable ( HTable )
18−import Rel8.Schema.HTable.Context ( HKTable )
19−
20−
21−type HTrio :: HKTable -> HKTable -> HKTable -> HKTable
22−data HTrio x y z context = HTrio
23− { hfst :: x context
24− , hsnd :: y context
25− , htrd :: z context
26− }
27− deriving stock Generic
28− deriving anyclass HTable
src/Rel8/Schema/HTable/Type.hsdeleted−56
@@ -1,56 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language GADTs #-}
3−{-# language StandaloneKindSignatures #-}
4−{-# language TypeFamilies #-}
5−{-# language UndecidableInstances #-}
6−
7−module Rel8.Schema.HTable.Type
8− ( HType(..)
9− )
10−where
11−
12−-- base
13−import Data.Kind ( Type )
14−import Data.Proxy ( Proxy( Proxy ) )
15−import Prelude
16−
17−-- rel8
18−import Rel8.Kind.Labels ( SLabels( SLabel ) )
19−import Rel8.Kind.Necessity ( Necessity( Required ), SNecessity( SRequired ) )
20−import Rel8.Schema.Dict ( Dict( Dict ) )
21−import Rel8.Schema.HTable
22− ( HTable, HConstrainTable, HField
23− , hfield, htabulate, htraverse, hdicts, hspecs
24− )
25−import Rel8.Schema.HTable.Context ( H, HKTable )
26−import Rel8.Schema.Nullability ( Unnullify, Nullabilizes, nullabilization )
27−import Rel8.Schema.Spec ( Context, Spec( Spec ), SSpec(..) )
28−import Rel8.Type ( DBType, typeInformation )
29−
30−
31−type HType :: Type -> HKTable
32−data HType a context where
33− HType ::
34− { unHType :: context ('Spec '[""] 'Required (Unnullify a) a)
35− } -> HType a (H context)
36−
37−
38−type HTypeField :: Type -> Context
39−data HTypeField a spec where
40− HTypeField :: HTypeField a ('Spec '[""] 'Required (Unnullify a) a)
41−
42−
43−instance (DBType db, Nullabilizes db a) => HTable (HType a) where
44− type HConstrainTable (HType a) c = c ('Spec '[""] 'Required (Unnullify a) a)
45− type HField (HType a) = HTypeField a
46−
47− hfield (HType a) HTypeField = a
48− htabulate f = HType $ f HTypeField
49− htraverse f (HType a) = HType <$> f a
50− hdicts = HType Dict
51− hspecs = HType SSpec
52− { labels = SLabel Proxy
53− , necessity = SRequired
54− , info = typeInformation
55− , nullability = nullabilization
56− }
src/Rel8/Schema/HTable/Vectorize.hs+72−143
@@ -1,214 +1,143 @@
11{-# language AllowAmbiguousTypes #-}
22{-# language ConstraintKinds #-}
33{-# language DataKinds #-}
4+{-# language DeriveAnyClass #-}
5+{-# language DeriveGeneric #-}
6+{-# language DerivingStrategies #-}
47{-# language FlexibleContexts #-}
58{-# language FlexibleInstances #-}
69{-# language GADTs #-}
7−{-# language InstanceSigs #-}
10+{-# language LambdaCase #-}
811{-# language MultiParamTypeClasses #-}
9−{-# language NamedFieldPuns #-}
10−{-# language QuantifiedConstraints #-}
1112{-# language RankNTypes #-}
1213{-# language RecordWildCards #-}
1314{-# language ScopedTypeVariables #-}
1415{-# language StandaloneKindSignatures #-}
1516{-# language TypeApplications #-}
1617{-# language TypeFamilies #-}
17−{-# language TypeOperators #-}
1818{-# language UndecidableInstances #-}
1919
2020module Rel8.Schema.HTable.Vectorize
21− ( HVectorize( HVectorize )
21+ ( HVectorize
2222 , hvectorize, hunvectorize
2323 , happend, hempty
24− , hrelabel
24+ , hproject
25+ , hcolumn
2526 )
2627where
2728
2829-- base
2930import Data.Kind ( Constraint, Type )
3031import Data.List.NonEmpty ( NonEmpty )
31−import Data.Type.Equality ( (:~:)( Refl ) )
32+import GHC.Generics (Generic)
3233import Prelude
3334
3435-- rel8
35−import Rel8.Schema.Context.Label ( Labelable, labeler, unlabeler )
36+import Rel8.FCF ( Eval, Exp )
3637import Rel8.Schema.Dict ( Dict( Dict ) )
37−import Rel8.Schema.HTable
38− ( HTable, HConstrainTable, HField
39− , hfield, htabulate, htabulateA, htraverse, hdicts, hspecs
38+import qualified Rel8.Schema.Kind as K
39+import Rel8.Schema.HTable ( HTable, hfield, htabulate, htabulateA, hspecs )
40+import Rel8.Schema.HTable.Identity ( HIdentity( HIdentity ) )
41+import Rel8.Schema.HTable.MapTable
42+ ( HMapTable( HMapTable ), HMapTableField( HMapTableField )
43+ , MapSpec, mapInfo
44+ , Precompose( Precompose )
4045 )
41−import Rel8.Schema.HTable.Context ( H, HKTable )
42−import Rel8.Schema.Nullability ( IsMaybe, Nullability( NonNullable ) )
43−import Rel8.Schema.Spec ( Context, Spec( Spec ), SSpec(..) )
46+import qualified Rel8.Schema.HTable.MapTable as HMapTable ( hproject )
47+import Rel8.Schema.Null ( Unnullify, NotNull, Nullity( NotNull ) )
48+import Rel8.Schema.Spec ( Spec(..) )
4449import Rel8.Type.Array ( listTypeInformation, nonEmptyTypeInformation )
4550import Rel8.Type.Information ( TypeInformation )
4651
4752-- semialign
48−import Data.Zip ( Unzip, Repeat, Zippy(..) )
53+import Data.Zip ( Unzip, Zip, Zippy(..) )
4954
5055
56+type Vector :: (Type -> Type) -> Constraint
5157class Vector list where
52− listIsn'tMaybe :: proxy a -> IsMaybe (list a) :~: 'False
58+ listNotNull :: proxy a -> Dict NotNull (list a)
5359 vectorTypeInformation :: ()
54− => Nullability a ma
55− -> TypeInformation a
56− -> TypeInformation (list ma)
60+ => Nullity a
61+ -> TypeInformation (Unnullify a)
62+ -> TypeInformation (list a)
5763
5864
5965instance Vector [] where
60− listIsn'tMaybe _ = Refl
66+ listNotNull _ = Dict
6167 vectorTypeInformation = listTypeInformation
6268
6369
6470instance Vector NonEmpty where
65− listIsn'tMaybe _ = Refl
71+ listNotNull _ = Dict
6672 vectorTypeInformation = nonEmptyTypeInformation
6773
6874
69−type HVectorize :: (Type -> Type) -> HKTable -> HKTable
70−data HVectorize list table context where
71− HVectorize :: table (H (VectorizeSpec list context)) -> HVectorize list table (H context)
75+type HVectorize :: (Type -> Type) -> K.HTable -> K.HTable
76+newtype HVectorize list table context = HVectorize (HMapTable (Vectorize list) table context)
77+ deriving stock Generic
78+ deriving anyclass HTable
7279
7380
74−type HVectorizeField :: (Type -> Type) -> HKTable -> Context
75−data HVectorizeField list table spec where
76− HVectorizeField
77− :: HField table ('Spec labels necessity db a)
78− -> HVectorizeField list table
79− ('Spec labels necessity (list a) (list a)
80− )
81+data Vectorize :: (Type -> Type) -> Type -> Exp Type
8182
8283
83−instance (HTable table, Vector list) => HTable (HVectorize list table) where
84+type instance Eval (Vectorize list a) = list a
8485
85− type HField (HVectorize list table) = HVectorizeField list table
86− type HConstrainTable (HVectorize list table) c =
87− HConstrainTable table (VectorizeSpecC list c)
8886
89− hfield (HVectorize table) (HVectorizeField field) =
90− getVectorizeSpec (hfield table field)
91−
92− htabulate f = HVectorize $ htabulate $ \field -> case hfield hspecs field of
93− SSpec {} -> VectorizeSpec (f (HVectorizeField field))
94− htraverse f (HVectorize t) = HVectorize <$> htraverse (traverseVectorizeSpec f) t
95−
96− hdicts :: forall c. HConstrainTable table (VectorizeSpecC list c) =>
97− HVectorize list table (H (Dict c))
98− hdicts = HVectorize $ htabulate $ \field -> case hfield hspecs field of
99− SSpec {} -> case hfield (hdicts @_ @(VectorizeSpecC list c)) field of
100− Dict -> VectorizeSpec Dict
101−
102− hspecs = HVectorize $ htabulate $ \field -> case hfield hspecs field of
103− SSpec {..} -> case listIsn'tMaybe @list nullability of
104− Refl -> VectorizeSpec SSpec
105− { nullability = NonNullable
106− , info = vectorTypeInformation nullability info
87+instance Vector list => MapSpec (Vectorize list) where
88+ mapInfo = \case
89+ Spec {..} -> case listNotNull @list nullity of
90+ Dict -> Spec
91+ { nullity = NotNull
92+ , info = vectorTypeInformation nullity info
10793 , ..
10894 }
10995
110− {-# INLINABLE hfield #-}
111− {-# INLINABLE htabulate #-}
112− {-# INLINABLE htraverse #-}
113− {-# INLINABLE hdicts #-}
114− {-# INLINABLE hspecs #-}
115−
116−
117−type VectorizingSpec :: Type -> Type
118−type VectorizingSpec r = (Type -> Type) -> (Spec -> r) -> Spec -> r
119−
120−
121−type VectorizeSpec :: VectorizingSpec Type
122−data VectorizeSpec list context spec where
123− VectorizeSpec ::
124− { getVectorizeSpec :: context ('Spec labels necessity (list a) (list a))
125− } -> VectorizeSpec list context ('Spec labels necessity db a)
126−
127−
128−instance Labelable context => Labelable (VectorizeSpec list context) where
129− labeler (VectorizeSpec a) = VectorizeSpec (labeler a)
130− unlabeler (VectorizeSpec a) = VectorizeSpec (unlabeler a)
131−
13296
133−type VectorizeSpecC :: VectorizingSpec Constraint
134−class
135− ( forall labels necessity db a.
136− ( spec ~ 'Spec labels necessity db a
137− => constraint ('Spec labels necessity (list a) (list a))
138− )
139− )
140− => VectorizeSpecC list constraint spec
141−instance
142− ( spec ~ 'Spec labels necessity db a
143− , constraint ('Spec labels necessity (list a) (list a))
144− )
145− => VectorizeSpecC list constraint spec
146−
147−
148−traverseVectorizeSpec :: forall context context' list spec m. Functor m
149− => (forall x. context x -> m (context' x))
150− -> VectorizeSpec list context spec
151− -> m (VectorizeSpec list context' spec)
152−traverseVectorizeSpec f (VectorizeSpec a) = VectorizeSpec <$> f a
153−
154−
155−hvectorize :: (HTable t, Unzip f)
156− => (forall labels necessity db a. ()
157− => SSpec ('Spec labels necessity db a)
158− -> f (context ('Spec labels necessity db a))
159− -> context' ('Spec labels necessity (list a) (list a)))
160− -> f (t (H context))
161− -> HVectorize list t (H context')
162−hvectorize vectorizer as = HVectorize $ htabulate $ \field ->
97+hvectorize :: (HTable t, Unzip f, Vector list)
98+ => (forall a. Spec a -> f (context a) -> context' (list a))
99+ -> f (t context)
100+ -> HVectorize list t context'
101+hvectorize vectorizer as = HVectorize $ htabulate $ \(HMapTableField field) ->
163102 case hfield hspecs field of
164− spec@SSpec {} -> VectorizeSpec (vectorizer spec (fmap (`hfield` field) as))
103+ spec -> vectorizer spec (fmap (`hfield` field) as)
165104{-# INLINABLE hvectorize #-}
166105
167106
168−hunvectorize :: (HTable t, Repeat f)
169− => (forall labels necessity db a. ()
170− => SSpec ('Spec labels necessity db a)
171− -> context ('Spec labels necessity (list a) (list a))
172− -> f (context' ('Spec labels necessity db a)))
173− -> HVectorize list t (H context)
174− -> f (t (H context'))
107+hunvectorize :: (HTable t, Zip f, Vector list)
108+ => (forall a. Spec a -> context (list a) -> f (context' a))
109+ -> HVectorize list t context
110+ -> f (t context')
175111hunvectorize unvectorizer (HVectorize table) =
176112 getZippy $ htabulateA $ \field -> case hfield hspecs field of
177− spec -> case hfield table field of
178− VectorizeSpec a -> Zippy (unvectorizer spec a)
113+ spec -> case hfield table (HMapTableField field) of
114+ a -> Zippy (unvectorizer spec a)
179115{-# INLINABLE hunvectorize #-}
180116
181117
182−happend :: HTable t =>
183− ( forall labels necessity db a. ()
184− => Nullability db a
185− -> TypeInformation db
186− -> context ('Spec labels necessity (list a) (list a))
187− -> context ('Spec labels necessity (list a) (list a))
188− -> context ('Spec labels necessity (list a) (list a))
189− )
190− -> HVectorize list t (H context)
191− -> HVectorize list t (H context)
192− -> HVectorize list t (H context)
118+happend :: (HTable t, Vector list)
119+ => (forall a. Spec a -> context (list a) -> context (list a) -> context (list a))
120+ -> HVectorize list t context
121+ -> HVectorize list t context
122+ -> HVectorize list t context
193123happend append (HVectorize as) (HVectorize bs) = HVectorize $
194− htabulate $ \field -> case (hfield as field, hfield bs field) of
195− (VectorizeSpec a, VectorizeSpec b) -> case hfield hspecs field of
196− SSpec {nullability, info} -> VectorizeSpec $ append nullability info a b
124+ htabulate $ \field@(HMapTableField j) -> case (hfield as field, hfield bs field) of
125+ (a, b) -> case hfield hspecs j of
126+ spec -> append spec a b
197127
198128
199−hempty :: HTable t =>
200− ( forall labels necessity db a. ()
201− => Nullability db a
202− -> TypeInformation db
203− -> context ('Spec labels necessity [a] [a])
204− )
205− -> HVectorize [] t (H context)
206−hempty empty = HVectorize $ htabulate $ \field -> case hfield hspecs field of
207− SSpec {nullability, info} -> VectorizeSpec (empty nullability info)
129+hempty :: HTable t
130+ => (forall a. Spec a -> context [a])
131+ -> HVectorize [] t context
132+hempty empty = HVectorize $ htabulate $ \(HMapTableField field) ->
133+ empty (hfield hspecs field)
134+
135+
136+hproject :: ()
137+ => (forall ctx. t ctx -> t' ctx)
138+ -> HVectorize list t context -> HVectorize list t' context
139+hproject f (HVectorize a) = HVectorize (HMapTable.hproject f a)
208140
209141
210−hrelabel :: Labelable context
211− => (forall ctx. Labelable ctx => t (H ctx) -> u (H ctx))
212− -> HVectorize list t (H context)
213− -> HVectorize list u (H context)
214−hrelabel f (HVectorize table) = HVectorize (f table)
142+hcolumn :: HVectorize list (HIdentity a) context -> context (list a)
143+hcolumn (HVectorize (HMapTable (HIdentity (Precompose a)))) = a
src/Rel8/Schema/Kind.hsnew file+24
@@ -0,0 +1,24 @@
1+{-# language StandaloneKindSignatures #-}
2+
3+module Rel8.Schema.Kind
4+ ( Rel8able
5+ , Context
6+ , HTable
7+ )
8+where
9+
10+-- base
11+import Data.Kind ( Type )
12+import Prelude ()
13+
14+
15+type Context :: Type
16+type Context = Type -> Type
17+
18+
19+type HTable :: Type
20+type HTable = Context -> Type
21+
22+
23+type Rel8able :: Type
24+type Rel8able = Context -> Type
src/Rel8/Schema/Name.hsnew file+77
@@ -0,0 +1,77 @@
1+{-# language DataKinds #-}
2+{-# language DerivingStrategies #-}
3+{-# language FlexibleContexts #-}
4+{-# language FlexibleInstances #-}
5+{-# language GADTs #-}
6+{-# language GeneralizedNewtypeDeriving #-}
7+{-# language MultiParamTypeClasses #-}
8+{-# language RankNTypes #-}
9+{-# language StandaloneKindSignatures #-}
10+{-# language TypeFamilies #-}
11+{-# language UndecidableInstances #-}
12+
13+module Rel8.Schema.Name
14+ ( Name(..)
15+ , Selects
16+ , ppColumn
17+ )
18+where
19+
20+-- base
21+import Data.Functor.Identity ( Identity( Identity ) )
22+import Data.Kind ( Constraint, Type )
23+import Data.String ( IsString )
24+import Prelude
25+
26+-- opaleye
27+import qualified Opaleye.Internal.HaskellDB.Sql as Opaleye
28+import qualified Opaleye.Internal.HaskellDB.Sql.Print as Opaleye
29+
30+-- pretty
31+import Text.PrettyPrint ( Doc )
32+
33+-- rel8
34+import Rel8.Expr ( Expr )
35+import qualified Rel8.Schema.Kind as K
36+import Rel8.Schema.HTable.Identity ( HIdentity( HIdentity ) )
37+import Rel8.Schema.Null ( Sql )
38+import Rel8.Table
39+ ( Table, Columns, Context, fromColumns, toColumns
40+ , FromExprs, fromResult, toResult
41+ , Transpose
42+ )
43+import Rel8.Table.Transpose ( Transposes )
44+import Rel8.Type ( DBType )
45+
46+
47+-- | A @Name@ is the name of a column, as it would be defined in a table's
48+-- schema definition. You can construct names by using the @OverloadedStrings@
49+-- extension and writing string literals. This is typically done when providing
50+-- a 'TableSchema' value.
51+type Name :: K.Context
52+newtype Name a = Name String
53+ deriving stock Show
54+ deriving newtype IsString
55+
56+
57+instance Sql DBType a => Table Name (Name a) where
58+ type Columns (Name a) = HIdentity a
59+ type Context (Name a) = Name
60+ type FromExprs (Name a) = a
61+ type Transpose to (Name a) = to a
62+
63+ toColumns a = HIdentity a
64+ fromColumns (HIdentity a) = a
65+ toResult a = HIdentity (Identity a)
66+ fromResult (HIdentity (Identity a)) = a
67+
68+
69+-- | @Selects a b@ means that @a@ is a schema (i.e., a 'Table' of 'Name's) for
70+-- the 'Expr' columns in @b@.
71+type Selects :: Type -> Type -> Constraint
72+class Transposes Name Expr names exprs => Selects names exprs
73+instance Transposes Name Expr names exprs => Selects names exprs
74+
75+
76+ppColumn :: String -> Doc
77+ppColumn = Opaleye.ppSqlExpr . Opaleye.ColumnSqlExpr . Opaleye.SqlColumn
src/Rel8/Schema/Null.hsnew file+110
@@ -0,0 +1,110 @@
1+{-# language ConstraintKinds #-}
2+{-# language DataKinds #-}
3+{-# language FlexibleContexts #-}
4+{-# language FlexibleInstances #-}
5+{-# language GADTs #-}
6+{-# language MultiParamTypeClasses #-}
7+{-# language RankNTypes #-}
8+{-# language StandaloneKindSignatures #-}
9+{-# language TypeFamilies #-}
10+{-# language UndecidableInstances #-}
11+{-# language UndecidableSuperClasses #-}
12+
13+module Rel8.Schema.Null
14+ ( Nullify, Unnullify
15+ , NotNull
16+ , Homonullable
17+ , Nullity( Null, NotNull )
18+ , Nullable, nullable
19+ , Sql
20+ )
21+where
22+
23+-- base
24+import Data.Kind ( Constraint, Type )
25+import Prelude
26+
27+
28+type IsMaybe :: Type -> Bool
29+type family IsMaybe a where
30+ IsMaybe (Maybe _) = 'True
31+ IsMaybe _ = 'False
32+
33+
34+type Unnullify' :: Bool -> Type -> Type
35+type family Unnullify' isMaybe ma where
36+ Unnullify' 'False a = a
37+ Unnullify' 'True (Maybe a) = a
38+
39+
40+type Unnullify :: Type -> Type
41+type Unnullify a = Unnullify' (IsMaybe a) a
42+
43+
44+type Nullify' :: Bool -> Type -> Type
45+type family Nullify' isMaybe a where
46+ Nullify' 'False a = a
47+ Nullify' 'True a = Maybe a
48+
49+
50+type Nullify :: Type -> Type
51+type Nullify a = Maybe (Unnullify a)
52+
53+
54+-- | @nullify a@ means @a@ cannot take @null@ as a value.
55+type NotNull :: Type -> Constraint
56+class (Nullable a, IsMaybe a ~ 'False) => NotNull a
57+instance (Nullable a, IsMaybe a ~ 'False) => NotNull a
58+
59+
60+-- | @Homonullable a b@ means that both @a@ and @b@ can be @null@, or neither
61+-- @a@ or @b@ can be @null@.
62+type Homonullable :: Type -> Type -> Constraint
63+class IsMaybe a ~ IsMaybe b => Homonullable a b
64+instance IsMaybe a ~ IsMaybe b => Homonullable a b
65+
66+
67+type Nullity :: Type -> Type
68+data Nullity a where
69+ NotNull :: NotNull a => Nullity a
70+ Null :: NotNull a => Nullity (Maybe a)
71+
72+
73+type Nullable' :: Bool -> Type -> Constraint
74+class
75+ ( IsMaybe a ~ isMaybe
76+ , IsMaybe (Unnullify a) ~ 'False
77+ , Nullify' isMaybe (Unnullify a) ~ a
78+ ) => Nullable' isMaybe a
79+ where
80+ nullable' :: Nullity a
81+
82+
83+instance IsMaybe a ~ 'False => Nullable' 'False a where
84+ nullable' = NotNull
85+
86+
87+instance IsMaybe a ~ 'False => Nullable' 'True (Maybe a) where
88+ nullable' = Null
89+
90+
91+-- | @Nullable a@ means that @rel8@ is able to check if the type @a@ is a
92+-- type that can take @null@ values or not.
93+type Nullable :: Type -> Constraint
94+class Nullable' (IsMaybe a) a => Nullable a
95+instance Nullable' (IsMaybe a) a => Nullable a
96+
97+
98+nullable :: Nullable a => Nullity a
99+nullable = nullable'
100+
101+
102+-- | The @Sql@ type class describes both null and not null database values,
103+-- constrained by a specific class.
104+--
105+-- For example, if you see @Sql DBEq a@, this means any database type that
106+-- supports equality, and @a@ can either be exactly an @a@, or it could also be
107+-- @Maybe a@.
108+type Sql :: (Type -> Constraint) -> Type -> Constraint
109+class (constraint (Unnullify a), Nullable a) => Sql constraint a
110+instance (constraint (Unnullify a), Nullable a) => Sql constraint a
src/Rel8/Schema/Nullability.hsdeleted−86
@@ -1,86 +0,0 @@
1−{-# language ConstraintKinds #-}
2−{-# language DataKinds #-}
3−{-# language FlexibleContexts #-}
4−{-# language FlexibleInstances #-}
5−{-# language FunctionalDependencies #-}
6−{-# language GADTs #-}
7−{-# language MultiParamTypeClasses #-}
8−{-# language QuantifiedConstraints #-}
9−{-# language StandaloneKindSignatures #-}
10−{-# language TypeFamilies #-}
11−{-# language UndecidableInstances #-}
12−
13−module Rel8.Schema.Nullability
14− ( IsMaybe, Nullify, Unnullify
15− , Nullability( Nullable, NonNullable )
16− , Nullabilizes, nullabilization
17− )
18−where
19−
20−-- base
21−import Data.Kind ( Constraint, Type )
22−import Prelude
23−
24−-- rel8
25−import Rel8.Opaque ( Opaque )
26−
27−
28−type IsMaybe :: Type -> Bool
29−type family IsMaybe a where
30− IsMaybe (Maybe _) = 'True
31− IsMaybe _ = 'False
32−
33−
34−type Unnullify' :: Bool -> Type -> Type
35−type family Unnullify' isMaybe ma where
36− Unnullify' 'False a = a
37− Unnullify' 'True (Maybe a) = a
38−
39−
40−type Unnullify :: Type -> Type
41−type Unnullify a = Unnullify' (IsMaybe a) a
42−
43−
44−type Nullify' :: Bool -> Type -> Type
45−type family Nullify' isMaybe a where
46− Nullify' 'False a = a
47− Nullify' 'True a = Maybe a
48−
49−
50−type Nullify :: Type -> Type
51−type Nullify a = Maybe (Unnullify a)
52−
53−
54−type Nullability :: Type -> Type -> Type
55−data Nullability a ma where
56− NonNullable :: IsMaybe a ~ 'False => Nullability a a
57− Nullable :: IsMaybe a ~ 'False => Nullability a (Maybe a)
58−
59−
60−type Nullabilizes' :: Bool -> Type -> Type -> Constraint
61−class
62− ( IsMaybe ma ~ isMaybe
63− , IsMaybe a ~ 'False
64− , Unnullify ma ~ a
65− , Nullify' isMaybe a ~ ma
66− ) => Nullabilizes' isMaybe a ma | isMaybe ma -> a, isMaybe a -> ma
67− where
68− nullabilization' :: Nullability a ma
69−
70−
71−instance IsMaybe a ~ 'False => Nullabilizes' 'False a a where
72− nullabilization' = NonNullable
73−
74−
75−instance IsMaybe a ~ 'False => Nullabilizes' 'True a (Maybe a) where
76− nullabilization' = Nullable
77−
78−
79−type Nullabilizes :: Type -> Type -> Constraint
80−class Nullabilizes' (IsMaybe ma) a ma => Nullabilizes a ma
81−instance Nullabilizes' (IsMaybe ma) a ma => Nullabilizes a ma
82−instance {-# OVERLAPPING #-} Nullabilizes Opaque Opaque
83−
84−
85−nullabilization :: forall a db. Nullabilizes db a => Nullability db a
86−nullabilization = nullabilization'
src/Rel8/Schema/Result.hsnew file+54
@@ -0,0 +1,54 @@
1+{-# language DataKinds #-}
2+{-# language GADTs #-}
3+{-# language NamedFieldPuns #-}
4+{-# language StandaloneKindSignatures #-}
5+{-# language TypeFamilies #-}
6+
7+module Rel8.Schema.Result
8+ ( Result
9+ , null, nullifier, unnullifier
10+ , vectorizer, unvectorizer
11+ )
12+where
13+
14+-- base
15+import Data.Functor.Identity ( Identity( Identity), runIdentity )
16+import Prelude hiding ( null )
17+
18+-- rel8
19+import Rel8.Schema.Kind ( Context )
20+import Rel8.Schema.Null ( Nullify, Nullity( Null, NotNull ) )
21+import Rel8.Schema.Spec ( Spec(..) )
22+
23+
24+-- | The @Result@ context is the context used for decoded query results.
25+--
26+-- When a query is executed against a PostgreSQL database, Rel8 parses the
27+-- returned rows, decoding each row into the @Result@ context.
28+type Result :: Context
29+type Result = Identity
30+
31+
32+null :: Result (Maybe a)
33+null = Identity Nothing
34+
35+
36+nullifier :: Spec a -> Result a -> Result (Nullify a)
37+nullifier Spec {nullity} (Identity a) = Identity $ case nullity of
38+ Null -> a
39+ NotNull -> Just a
40+
41+
42+unnullifier :: Spec a -> Result (Nullify a) -> Maybe (Result a)
43+unnullifier Spec {nullity} (Identity a) =
44+ case nullity of
45+ Null -> pure $ Identity a
46+ NotNull -> Identity <$> a
47+
48+
49+vectorizer :: Functor f => Spec a -> f (Result a) -> Result (f a)
50+vectorizer _ = Identity . fmap runIdentity
51+
52+
53+unvectorizer :: Functor f => Spec a -> Result (f a) -> f (Result a)
54+unvectorizer _ (Identity results) = Identity <$> results
src/Rel8/Schema/Spec.hs+18−55
@@ -1,71 +1,34 @@
1−{-# language DataKinds #-}
21{-# language FlexibleContexts #-}
3−{-# language GADTs #-}
2+{-# language MonoLocalBinds #-}
43{-# language StandaloneKindSignatures #-}
5−{-# language UndecidableInstances #-}
64
75module Rel8.Schema.Spec
8− ( Spec( Spec )
9− , SSpec( SSpec, labels, necessity, info, nullability )
10− , KnownSpec( specSing )
11− , Context, KTable
6+ ( Spec( Spec, labels, info, nullity )
7+ , specification
128 )
139where
1410
1511-- base
16−import Data.Kind ( Constraint, Type )
17−import Prelude ()
12+import Data.Kind ( Type )
13+import Prelude
1814
1915-- rel8
20−import Rel8.Kind.Labels ( Labels, SLabels, KnownLabels, labelsSing )
21−import Rel8.Kind.Necessity
22− ( Necessity
23− , SNecessity
24− , KnownNecessity, necessitySing
25− )
26−import Rel8.Schema.Nullability ( Nullability, Nullabilizes, nullabilization )
16+import Rel8.Schema.Null ( Nullity, Sql, Unnullify, nullable )
2717import Rel8.Type ( DBType, typeInformation )
2818import Rel8.Type.Information ( TypeInformation )
2919
3020
31−type Spec :: Type
32−data Spec = Spec Labels Necessity Type Type
33−
34−
35−type SSpec :: Spec -> Type
36−data SSpec spec where
37− SSpec ::
38− { labels :: SLabels labels
39− , necessity :: SNecessity necessity
40− , info :: TypeInformation db
41− , nullability :: Nullability db a
42− }
43− -> SSpec ('Spec labels necessity db a)
44−
45−
46−type KnownSpec :: Spec -> Constraint
47−class KnownSpec spec where
48− specSing :: SSpec spec
49−
50−
51−instance
52− ( KnownLabels labels
53− , KnownNecessity necessity
54− , DBType db
55− , Nullabilizes db a
56− ) => KnownSpec ('Spec labels necessity db a)
57− where
58− specSing = SSpec
59− { labels = labelsSing
60− , necessity = necessitySing
61− , info = typeInformation
62− , nullability = nullabilization
63− }
64−
65−
66−type Context :: Type
67−type Context = Spec -> Type
21+type Spec :: Type -> Type
22+data Spec a = Spec
23+ { labels :: [String]
24+ , info :: TypeInformation (Unnullify a)
25+ , nullity :: Nullity a
26+ }
6827
6928
70−type KTable :: Type
71−type KTable = Context -> Type
29+specification :: Sql DBType a => Spec a
30+specification = Spec
31+ { labels = []
32+ , info = typeInformation
33+ , nullity = nullable
34+ }
src/Rel8/Schema/Spec/ConstrainContext.hsdeleted−23
@@ -1,23 +0,0 @@
1−{-# language ConstraintKinds #-}
2−{-# language DataKinds #-}
3−{-# language FlexibleInstances #-}
4−{-# language MultiParamTypeClasses #-}
5−{-# language StandaloneKindSignatures #-}
6−{-# language UndecidableSuperClasses #-}
7−
8−module Rel8.Schema.Spec.ConstrainContext
9− ( ConstrainContext
10− )
11−where
12−
13−-- base
14−import Data.Kind ( Constraint, Type )
15−import Prelude ()
16−
17−-- rel8
18−import Rel8.Schema.Spec ( Context, Spec )
19−
20−
21−type ConstrainContext :: (Type -> Constraint) -> Context -> Spec -> Constraint
22−class constraint (context spec) => ConstrainContext constraint context spec
23−instance constraint (context spec) => ConstrainContext constraint context spec
src/Rel8/Schema/Spec/ConstrainDBType.hsdeleted−34
@@ -1,34 +0,0 @@
1−{-# language ConstraintKinds #-}
2−{-# language DataKinds #-}
3−{-# language FlexibleInstances #-}
4−{-# language MultiParamTypeClasses #-}
5−{-# language QuantifiedConstraints #-}
6−{-# language StandaloneKindSignatures #-}
7−{-# language TypeFamilies #-}
8−{-# language UndecidableInstances #-}
9−
10−module Rel8.Schema.Spec.ConstrainDBType
11− ( ConstrainDBType
12− )
13−where
14−
15−-- base
16−import Data.Kind ( Constraint, Type )
17−import Prelude ()
18−
19−-- rel8
20−import Rel8.Schema.Spec ( Spec( Spec ) )
21−
22−
23−type ConstrainDBType :: (Type -> Constraint) -> Spec -> Constraint
24−class
25− ( forall labels necessity db a. ()
26− => (spec ~ 'Spec labels necessity db a)
27− => constraint db
28− )
29− => ConstrainDBType constraint spec
30−instance
31− ( spec ~ 'Spec labels necessity db a
32− , constraint db
33− )
34− => ConstrainDBType constraint spec
src/Rel8/Schema/Spec/ConstrainType.hsdeleted−31
@@ -1,31 +0,0 @@
1−{-# language ConstraintKinds #-}
2−{-# language DataKinds #-}
3−{-# language FlexibleInstances #-}
4−{-# language MultiParamTypeClasses #-}
5−{-# language QuantifiedConstraints #-}
6−{-# language StandaloneKindSignatures #-}
7−{-# language TypeFamilies #-}
8−{-# language UndecidableInstances #-}
9−
10−module Rel8.Schema.Spec.ConstrainType
11− ( ConstrainType
12− )
13−where
14−
15−-- base
16−import Data.Kind ( Constraint, Type )
17−import Prelude ()
18−
19−-- rel8
20−import Rel8.Schema.Spec ( Spec( Spec ) )
21−
22−
23−type ConstrainType :: (Type -> Constraint) -> Spec -> Constraint
24−class
25− ( forall labels necessity db a. ()
26− => (spec ~ 'Spec labels necessity db a)
27− => constraint a
28− ) =>
29− ConstrainType constraint spec
30−instance (spec ~ 'Spec labels necessity db a, constraint a) =>
31− ConstrainType constraint spec
src/Rel8/Schema/Structure.hsdeleted−53
@@ -1,53 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language StandaloneKindSignatures #-}
3−{-# language PolyKinds #-}
4−{-# language TypeFamilies #-}
5−
6−module Rel8.Schema.Structure
7− ( Structure
8− , Shape( Column, Either, List, Maybe, NonEmpty, These )
9− , Shape1
10− , Shape2
11− , IsStructure
12− )
13−where
14−
15−-- base
16−import Data.Kind ( Type )
17−import Prelude
18−
19−-- rel8
20−import Rel8.Schema.Spec ( Context, Spec )
21−
22−
23−type Structure :: Context
24−data Structure spec
25−
26−
27−type Shape :: Type
28−data Shape
29− = Column Spec
30− | Either Type Type
31− | List Type
32− | Maybe Type
33− | NonEmpty Type
34− | These Type Type
35−
36−
37−type Shape1 :: (a -> Shape) -> a -> Type
38−data Shape1 shape a
39−
40−
41−type Shape2 :: (a -> b -> Shape) -> a -> b -> Type
42−data Shape2 shape a b
43−
44−
45−type IsStructure :: Type -> Bool
46−type family IsStructure a where
47− IsStructure (Shape1 _ _) = 'True
48− IsStructure (Shape2 _ _ _) = 'True
49− IsStructure (_, _) = 'True
50− IsStructure (_, _, _) = 'True
51− IsStructure (_, _, _, _) = 'True
52− IsStructure (_, _, _, _, _) = 'True
53− IsStructure _ = 'False
src/Rel8/Schema/Table.hs+31
@@ -1,18 +1,49 @@
11{-# language DeriveFunctor #-}
22{-# language DerivingStrategies #-}
3+{-# language DisambiguateRecordFields #-}
4+{-# language NamedFieldPuns #-}
5+{-# language StandaloneKindSignatures #-}
36
47module Rel8.Schema.Table
58 ( TableSchema(..)
9+ , ppTable
610 )
711where
812
913-- base
14+import Data.Kind ( Type )
1015import Prelude
1116
17+-- opaleye
18+import qualified Opaleye.Internal.HaskellDB.Sql as Opaleye
19+import qualified Opaleye.Internal.HaskellDB.Sql.Print as Opaleye
1220
21+-- pretty
22+import Text.PrettyPrint ( Doc )
23+
24+
25+-- | The schema for a table. This is used to specify the name and schema that a
26+-- table belongs to (the @FROM@ part of a SQL query), along with the schema of
27+-- the columns within this table.
28+--
29+-- For each selectable table in your database, you should provide a
30+-- @TableSchema@ in order to interact with the table via Rel8.
31+type TableSchema :: Type -> Type
1332data TableSchema names = TableSchema
1433 { name :: String
34+ -- ^ The name of the table.
1535 , schema :: Maybe String
36+ -- ^ The schema that this table belongs to. If 'Nothing', whatever is on
37+ -- the connection's @search_path@ will be used.
1638 , columns :: names
39+ -- ^ The columns of the table. Typically you would use a a higher-kinded
40+ -- data type here, parameterized by the 'Rel8.ColumnSchema.ColumnSchema' functor.
1741 }
1842 deriving stock Functor
43+
44+
45+ppTable :: TableSchema a -> Doc
46+ppTable TableSchema {name, schema} = Opaleye.ppTable Opaleye.SqlTable
47+ { sqlTableSchemaName = schema
48+ , sqlTableName = name
49+ }
src/Rel8/Statement/Delete.hs+40−49
@@ -1,88 +1,79 @@
11{-# language DuplicateRecordFields #-}
22{-# language GADTs #-}
33{-# language NamedFieldPuns #-}
4−{-# language ScopedTypeVariables #-}
4+{-# language RankNTypes #-}
5+{-# language RecordWildCards #-}
56{-# language StandaloneKindSignatures #-}
6−{-# language TypeApplications #-}
7+{-# language StrictData #-}
78
89module Rel8.Statement.Delete
910 ( Delete(..)
1011 , delete
12+ , ppDelete
1113 )
1214where
1315
1416-- base
15−import Control.Exception ( throwIO )
16−import Control.Monad ( (>=>) )
1717import Data.Kind ( Type )
1818import Prelude
1919
2020-- hasql
21−import Hasql.Connection ( Connection )
22−import qualified Hasql.Decoders as Hasql
2321import qualified Hasql.Encoders as Hasql
24−import qualified Hasql.Session as Hasql
2522import qualified Hasql.Statement as Hasql
2623
27−-- opaleye
28−import qualified Opaleye.Internal.Manipulation as Opaleye
24+-- pretty
25+import Text.PrettyPrint ( Doc, (<+>), ($$), text )
2926
3027-- rel8
3128import Rel8.Expr ( Expr )
32−import Rel8.Expr.Opaleye ( toColumn, toPrimExpr )
33−import Rel8.Schema.Table ( TableSchema )
34−import Rel8.Statement.Returning ( Returning( NumberOfRowsAffected, Projection ) )
35−import Rel8.Table ( fromColumns, toColumns )
36−import Rel8.Table.Opaleye ( table, unpackspec )
37−import Rel8.Table.Recontextualize ( Selects )
38−import Rel8.Table.Serialize ( Serializable, parse )
29+import Rel8.Query ( Query )
30+import Rel8.Schema.Name ( Selects )
31+import Rel8.Schema.Table ( TableSchema, ppTable )
32+import Rel8.Statement.Returning ( Returning, decodeReturning, ppReturning )
33+import Rel8.Statement.Using ( ppUsing )
34+import Rel8.Statement.Where ( ppWhere )
3935
4036-- text
4137import qualified Data.Text as Text
4238import Data.Text.Encoding ( encodeUtf8 )
4339
4440
41+-- | The constituent parts of a @DELETE@ statement.
4542type Delete :: Type -> Type
4643data Delete a where
4744 Delete :: Selects names exprs =>
4845 { from :: TableSchema names
49− , deleteWhere :: exprs -> Expr Bool
46+ -- ^ Which table to delete from.
47+ , using :: Query using
48+ -- ^ @USING@ clause — this can be used to join against other tables,
49+ -- and its results can be referenced in the @WHERE@ clause
50+ , deleteWhere :: using -> exprs -> Expr Bool
51+ -- ^ Which rows should be selected for deletion.
5052 , returning :: Returning names a
53+ -- ^ What to return from the @DELETE@ statement.
5154 }
5255 -> Delete a
5356
5457
55−delete :: Delete a -> Connection -> IO a
56−delete Delete {from, deleteWhere, returning} =
57− case returning of
58− NumberOfRowsAffected -> Hasql.run session >=> either throwIO pure
59− where
60− session = Hasql.statement () statement
61− statement = Hasql.Statement bytes params decode prepare
62− bytes = encodeUtf8 $ Text.pack sql
63− params = Hasql.noParams
64− decode = Hasql.rowsAffected
65− prepare = False
66− sql = Opaleye.arrangeDeleteSql from' where'
67− where
68− from' = table $ toColumns <$> from
69− where' = toColumn . toPrimExpr . deleteWhere . fromColumns
58+ppDelete :: Delete a -> Doc
59+ppDelete Delete {..} = case ppUsing using of
60+ Nothing ->
61+ text "DELETE FROM" <+> ppTable from $$
62+ text "WHERE false"
63+ Just (usingDoc, i) ->
64+ text "DELETE FROM" <+> ppTable from $$
65+ usingDoc $$
66+ ppWhere from (deleteWhere i) $$
67+ ppReturning from returning
7068
71− Projection project -> Hasql.run session >=> either throwIO pure
72− where
73− session = Hasql.statement () statement
74− statement = Hasql.Statement bytes params decode prepare
75− bytes = encodeUtf8 $ Text.pack sql
76− params = Hasql.noParams
77− decode = decoder project
78− prepare = False
79− sql =
80− Opaleye.arrangeDeleteReturningSql unpackspec from' where' project'
81− where
82− from' = table $ toColumns <$> from
83− where' = toColumn . toPrimExpr . deleteWhere . fromColumns
84− project' = toColumns . project . fromColumns
69+
70+-- | Run a 'Delete' statement.
71+delete :: Delete a -> Hasql.Statement () a
72+delete d@Delete {returning} = Hasql.Statement bytes params decode prepare
8573 where
86− decoder :: forall exprs projection a. Serializable projection a
87− => (exprs -> projection) -> Hasql.Result [a]
88− decoder _ = Hasql.rowList (parse @projection @a)
74+ bytes = encodeUtf8 $ Text.pack sql
75+ params = Hasql.noParams
76+ decode = decodeReturning returning
77+ prepare = False
78+ sql = show doc
79+ doc = ppDelete d
src/Rel8/Statement/Insert.hs+49−66
@@ -2,105 +2,88 @@
22{-# language FlexibleContexts #-}
33{-# language GADTs #-}
44{-# language NamedFieldPuns #-}
5−{-# language ScopedTypeVariables #-}
5+{-# language RecordWildCards #-}
66{-# language StandaloneKindSignatures #-}
7−{-# language TypeApplications #-}
7+{-# language StrictData #-}
88
99module Rel8.Statement.Insert
1010 ( Insert(..)
11− , OnConflict(..)
1211 , insert
12+ , ppInsert
13+ , ppInto
1314 )
1415where
1516
1617-- base
17−import Control.Exception ( throwIO )
18−import Control.Monad ( (>=>) )
18+import Data.Foldable ( toList )
1919import Data.Kind ( Type )
20−import Data.List.NonEmpty ( NonEmpty( (:|) ) )
2120import Prelude
2221
2322-- hasql
24−import Hasql.Connection ( Connection )
25−import qualified Hasql.Decoders as Hasql
2623import qualified Hasql.Encoders as Hasql
27−import qualified Hasql.Session as Hasql
2824import qualified Hasql.Statement as Hasql
2925
26+-- opaleye
27+import qualified Opaleye.Internal.HaskellDB.Sql.Print as Opaleye
28+
29+-- pretty
30+import Text.PrettyPrint ( Doc, (<+>), ($$), parens, text )
31+
3032-- rel8
31−import qualified Opaleye.Internal.Manipulation as Opaleye
32−import qualified Opaleye.Manipulation as Opaleye
33−import Rel8.Schema.Table ( TableSchema )
34−import Rel8.Statement.Returning ( Returning( Projection, NumberOfRowsAffected ) )
35−import Rel8.Table ( fromColumns, toColumns )
36−import Rel8.Table.Opaleye ( table, unpackspec )
37−import Rel8.Table.Recontextualize ( Inserts, Selects )
38−import Rel8.Table.Serialize ( Serializable, parse )
33+import Rel8.Query ( Query )
34+import Rel8.Schema.Name ( Name, Selects, ppColumn )
35+import Rel8.Schema.Table ( TableSchema(..), ppTable )
36+import Rel8.Statement.OnConflict ( OnConflict, ppOnConflict )
37+import Rel8.Statement.Returning ( Returning, decodeReturning, ppReturning )
38+import Rel8.Statement.Select ( ppRows )
39+import Rel8.Table ( Table )
40+import Rel8.Table.Name ( showNames )
3941
4042-- text
4143import qualified Data.Text as Text ( pack )
4244import Data.Text.Encoding ( encodeUtf8 )
4345
4446
47+-- | The constituent parts of a SQL @INSERT@ statement.
4548type Insert :: Type -> Type
4649data Insert a where
47− Insert :: (Selects names exprs, Inserts exprs inserts) =>
50+ Insert :: Selects names exprs =>
4851 { into :: TableSchema names
49− , rows :: [inserts]
50− , onConflict :: OnConflict
52+ -- ^ Which table to insert into.
53+ , rows :: Query exprs
54+ -- ^ The rows to insert. This can be an arbitrary query — use
55+ -- 'Rel8.values' insert a static list of rows.
56+ , onConflict :: OnConflict names
57+ -- ^ What to do if the inserted rows conflict with data already in the
58+ -- table.
5159 , returning :: Returning names a
60+ -- ^ What information to return on completion.
5261 }
5362 -> Insert a
5463
5564
56−data OnConflict = Abort | DoNothing
65+ppInsert :: Insert a -> Doc
66+ppInsert Insert {..} =
67+ text "INSERT INTO" <+>
68+ ppInto into $$
69+ ppRows rows $$
70+ ppOnConflict into onConflict $$
71+ ppReturning into returning
5772
5873
59−insert :: Insert a -> Connection -> IO a
60−insert Insert {into, rows, onConflict, returning} =
61− case (rows, returning) of
62− ([], NumberOfRowsAffected) -> const $ pure 0
63− ([], Projection _) -> const $ pure []
74+ppInto :: Table Name a => TableSchema a -> Doc
75+ppInto table@TableSchema {columns} =
76+ ppTable table <+>
77+ parens (Opaleye.commaV ppColumn (toList (showNames columns)))
6478
65− (x:xs, NumberOfRowsAffected) -> Hasql.run session >=> either throwIO pure
66− where
67− session = Hasql.statement () statement
68− statement = Hasql.Statement bytes params decode prepare
69− bytes = encodeUtf8 $ Text.pack sql
70− params = Hasql.noParams
71− decode = Hasql.rowsAffected
72− prepare = False
73− sql = Opaleye.arrangeInsertManySql into' rows' onConflict'
74− where
75− into' = table $ toColumns <$> into
76− rows' = toColumns <$> x :| xs
77−
78− (x:xs, Projection project) -> Hasql.run session >=> either throwIO pure
79− where
80− session = Hasql.statement () statement
81− statement = Hasql.Statement bytes params decode prepare
82− bytes = encodeUtf8 $ Text.pack sql
83− params = Hasql.noParams
84− decode = decoder project
85− prepare = False
86− sql =
87− Opaleye.arrangeInsertManyReturningSql
88− unpackspec
89− into'
90− rows'
91− project'
92− onConflict'
93− where
94− into' = table $ toColumns <$> into
95− rows' = toColumns <$> x :| xs
96− project' = toColumns . project . fromColumns
9779
80+-- | Run an 'Insert' statement.
81+insert :: Insert a -> Hasql.Statement () a
82+insert i@Insert {returning} = Hasql.Statement bytes params decode prepare
9883 where
99− onConflict' =
100− case onConflict of
101− DoNothing -> Just Opaleye.DoNothing
102− Abort -> Nothing
103−
104− decoder :: forall exprs projection a. Serializable projection a
105− => (exprs -> projection) -> Hasql.Result [a]
106− decoder _ = Hasql.rowList (parse @projection @a)
84+ bytes = encodeUtf8 $ Text.pack sql
85+ params = Hasql.noParams
86+ decode = decodeReturning returning
87+ prepare = False
88+ sql = show doc
89+ doc = ppInsert i
src/Rel8/Statement/OnConflict.hsnew file+106
@@ -0,0 +1,106 @@
1+{-# language DuplicateRecordFields #-}
2+{-# language FlexibleContexts #-}
3+{-# language GADTs #-}
4+{-# language LambdaCase #-}
5+{-# language NamedFieldPuns #-}
6+{-# language RecordWildCards #-}
7+{-# language StandaloneKindSignatures #-}
8+{-# language StrictData #-}
9+
10+module Rel8.Statement.OnConflict
11+ ( OnConflict(..)
12+ , Upsert(..)
13+ , ppOnConflict
14+ )
15+where
16+
17+-- base
18+import Data.Foldable ( toList )
19+import Data.Kind ( Type )
20+import Prelude
21+
22+-- opaleye
23+import qualified Opaleye.Internal.HaskellDB.Sql.Print as Opaleye
24+
25+-- pretty
26+import Text.PrettyPrint ( Doc, (<+>), ($$), parens, text )
27+
28+-- rel8
29+import Rel8.Expr ( Expr )
30+import Rel8.Schema.Name ( Name, Selects, ppColumn )
31+import Rel8.Schema.Table ( TableSchema(..) )
32+import Rel8.Statement.Set ( ppSet )
33+import Rel8.Statement.Where ( ppWhere )
34+import Rel8.Table ( Table, toColumns )
35+import Rel8.Table.Cols ( Cols( Cols ) )
36+import Rel8.Table.Name ( showNames )
37+import Rel8.Table.Opaleye ( attributes )
38+import Rel8.Table.Projection ( Projecting, Projection, apply )
39+
40+
41+-- | 'OnConflict' represents the @ON CONFLICT@ clause of an @INSERT@
42+-- statement. This specifies what ought to happen when one or more of the
43+-- rows proposed for insertion conflict with an existing row in the table.
44+type OnConflict :: Type -> Type
45+data OnConflict names
46+ = Abort
47+ -- ^ Abort the transaction if there are conflicting rows (Postgres' default)
48+ | DoNothing
49+ -- ^ @ON CONFLICT DO NOTHING@
50+ | DoUpdate (Upsert names)
51+ -- ^ @ON CONFLICT DO UPDATE@
52+
53+
54+-- | The @ON CONFLICT (...) DO UPDATE@ clause of an @INSERT@ statement, also
55+-- known as \"upsert\".
56+--
57+-- When an existing row conflicts with a row proposed for insertion,
58+-- @ON CONFLICT DO UPDATE@ allows you to instead update this existing row. The
59+-- conflicting row proposed for insertion is then \"excluded\", but its values
60+-- can still be referenced from the @SET@ and @WHERE@ clauses of the @UPDATE@
61+-- statement.
62+--
63+-- Upsert in Postgres requires an explicit set of \"conflict targets\" — the
64+-- set of columns comprising the @UNIQUE@ index from conflicts with which we
65+-- would like to recover.
66+type Upsert :: Type -> Type
67+data Upsert names where
68+ Upsert :: (Selects names exprs, Projecting names index, excluded ~ exprs) =>
69+ { index :: Projection names index
70+ -- ^ The set of conflict targets, projected from the set of columns for
71+ -- the whole table
72+ , set :: excluded -> exprs -> exprs
73+ -- ^ How to update each selected row.
74+ , updateWhere :: excluded -> exprs -> Expr Bool
75+ -- ^ Which rows to select for update.
76+ }
77+ -> Upsert names
78+
79+
80+ppOnConflict :: TableSchema names -> OnConflict names -> Doc
81+ppOnConflict schema = \case
82+ Abort -> mempty
83+ DoNothing -> text "ON CONFLICT DO NOTHING"
84+ DoUpdate upsert -> ppUpsert schema upsert
85+
86+
87+ppUpsert :: TableSchema names -> Upsert names -> Doc
88+ppUpsert schema@TableSchema {columns} Upsert {..} =
89+ text "ON CONFLICT" <+>
90+ ppIndex schema index <+>
91+ text "DO UPDATE" $$
92+ ppSet schema (set excluded) $$
93+ ppWhere schema (updateWhere excluded)
94+ where
95+ excluded = attributes TableSchema
96+ { schema = Nothing
97+ , name = "excluded"
98+ , columns
99+ }
100+
101+
102+ppIndex :: (Table Name names, Projecting names index)
103+ => TableSchema names -> Projection names index -> Doc
104+ppIndex TableSchema {columns} index =
105+ parens $ Opaleye.commaV ppColumn $ toList $
106+ showNames $ Cols $ apply index $ toColumns columns
src/Rel8/Statement/Returning.hs+115−6
@@ -1,24 +1,133 @@
11{-# language GADTs #-}
2+{-# language LambdaCase #-}
3+{-# language NamedFieldPuns #-}
4+{-# language RankNTypes #-}
5+{-# language ScopedTypeVariables #-}
26{-# language StandaloneKindSignatures #-}
7+{-# language StrictData #-}
8+{-# language TypeApplications #-}
39
410module Rel8.Statement.Returning
5− ( Returning(..)
11+ ( Returning( NumberOfRowsAffected, Projection )
12+ , decodeReturning
13+ , ppReturning
614 )
715where
816
917-- base
18+import Control.Applicative ( liftA2 )
19+import Data.Foldable ( toList )
1020import Data.Int ( Int64 )
1121import Data.Kind ( Type )
12−import Prelude ()
22+import Data.List.NonEmpty ( NonEmpty )
23+import Prelude
24+
25+-- hasql
26+import qualified Hasql.Decoders as Hasql
27+
28+-- opaleye
29+import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
30+import qualified Opaleye.Internal.HaskellDB.Sql.Print as Opaleye
31+import qualified Opaleye.Internal.Sql as Opaleye
32+
33+-- pretty
34+import Text.PrettyPrint ( Doc, (<+>), text )
1335
1436-- rel8
15−import Rel8.Table.Recontextualize ( Selects )
16−import Rel8.Table.Serialize ( Serializable )
37+import Rel8.Schema.Name ( Selects )
38+import Rel8.Schema.Table ( TableSchema(..) )
39+import Rel8.Table.Opaleye ( castTable, exprs, view )
40+import Rel8.Table.Serialize ( Serializable, parse )
1741
42+-- semigropuoids
43+import Data.Functor.Apply ( Apply, (<.>) )
1844
45+
46+-- | 'Rel8.Insert', 'Rel8.Update' and 'Rel8.Delete' all support returning either
47+-- the number of rows affected, or the actual rows modified.
1948type Returning :: Type -> Type -> Type
2049data Returning names a where
50+ Pure :: a -> Returning names a
51+ Ap :: Returning names (a -> b) -> Returning names a -> Returning names b
52+
53+ -- | Return the number of rows affected.
2154 NumberOfRowsAffected :: Returning names Int64
22− Projection :: (Selects names exprs, Serializable projection a)
23− => (exprs -> projection)
55+
56+ -- | 'Projection' allows you to project out of the affected rows, which can
57+ -- be useful if you want to log exactly which rows were deleted, or to view
58+ -- a generated id (for example, if using a column with an autoincrementing
59+ -- counter via 'Rel8.nextval').
60+ Projection :: (Selects names exprs, Serializable returning a)
61+ => (exprs -> returning)
2462 -> Returning names [a]
63+
64+
65+instance Functor (Returning names) where
66+ fmap f = \case
67+ Pure a -> Pure (f a)
68+ Ap g a -> Ap (fmap (f .) g) a
69+ m -> Ap (Pure f) m
70+
71+
72+instance Apply (Returning names) where
73+ (<.>) = Ap
74+
75+
76+instance Applicative (Returning names) where
77+ pure = Pure
78+ (<*>) = Ap
79+
80+
81+projections :: ()
82+ => TableSchema names -> Returning names a -> Maybe (NonEmpty Opaleye.PrimExpr)
83+projections schema@TableSchema {columns} = \case
84+ Pure _ -> Nothing
85+ Ap f a -> projections schema f <> projections schema a
86+ NumberOfRowsAffected -> Nothing
87+ Projection f -> Just (exprs (castTable (f (view columns))))
88+
89+
90+runReturning :: ()
91+ => ((Int64 -> a) -> r)
92+ -> (forall x. Hasql.Row x -> ([x] -> a) -> r)
93+ -> Returning names a
94+ -> r
95+runReturning rowCount rowList = \case
96+ Pure a -> rowCount (const a)
97+ Ap fs as ->
98+ runReturning
99+ (\withCount ->
100+ runReturning
101+ (\withCount' -> rowCount (withCount <*> withCount'))
102+ (\decoder -> rowList decoder . liftA2 withCount length64)
103+ as)
104+ (\decoder withRows ->
105+ runReturning
106+ (\withCount -> rowList decoder $ withRows <*> withCount . length64)
107+ (\decoder' withRows' ->
108+ rowList (liftA2 (,) decoder decoder') $
109+ withRows <$> fmap fst <*> withRows' . fmap snd)
110+ as)
111+ fs
112+ NumberOfRowsAffected -> rowCount id
113+ Projection (_ :: exprs -> returning) -> rowList decoder' id
114+ where
115+ decoder' = parse @returning
116+ where
117+ length64 :: Foldable f => f x -> Int64
118+ length64 = fromIntegral . length
119+
120+
121+decodeReturning :: Returning names a -> Hasql.Result a
122+decodeReturning = runReturning
123+ (<$> Hasql.rowsAffected)
124+ (\decoder withRows -> withRows <$> Hasql.rowList decoder)
125+
126+
127+ppReturning :: TableSchema names -> Returning names a -> Doc
128+ppReturning schema returning = case projections schema returning of
129+ Nothing -> mempty
130+ Just columns ->
131+ text "RETURNING" <+> Opaleye.commaV Opaleye.ppSqlExpr (toList sqlExprs)
132+ where
133+ sqlExprs = Opaleye.sqlExpr <$> columns
src/Rel8/Statement/SQL.hsnew file+29
@@ -0,0 +1,29 @@
1+module Rel8.Statement.SQL
2+ ( showDelete
3+ , showInsert
4+ , showUpdate
5+ )
6+where
7+
8+-- base
9+import Prelude
10+
11+-- rel8
12+import Rel8.Statement.Delete ( Delete, ppDelete )
13+import Rel8.Statement.Insert ( Insert, ppInsert )
14+import Rel8.Statement.Update ( Update, ppUpdate )
15+
16+
17+-- | Convert a 'Delete' to a 'String' containing a @DELETE@ statement.
18+showDelete :: Delete a -> String
19+showDelete = show . ppDelete
20+
21+
22+-- | Convert an 'Insert' to a 'String' containing an @INSERT@ statement.
23+showInsert :: Insert a -> String
24+showInsert = show . ppInsert
25+
26+
27+-- | Convert an 'Update' to a 'String' containing an @UPDATE@ statement.
28+showUpdate :: Update a -> String
29+showUpdate = show . ppUpdate
src/Rel8/Statement/Select.hs+122−36
@@ -1,61 +1,147 @@
1+{-# language DeriveTraversable #-}
2+{-# language DerivingStrategies #-}
3+{-# language FlexibleContexts #-}
4+{-# language MonoLocalBinds #-}
15{-# language ScopedTypeVariables #-}
6+{-# language StandaloneKindSignatures #-}
27{-# language TypeApplications #-}
38
49module Rel8.Statement.Select
510 ( select
6− , selectWithNames
11+ , ppSelect
12+
13+ , Optimized(..)
14+ , ppPrimSelect
15+ , ppRows
716 )
817where
918
1019-- base
11−import Control.Exception ( throwIO )
12−import Control.Monad ( (>=>) )
13−import Prelude
20+import Data.Foldable ( toList )
21+import Data.Kind ( Type )
22+import Data.Void ( Void )
23+import Prelude hiding ( undefined )
1424
1525-- hasql
16−import Hasql.Connection ( Connection )
1726import qualified Hasql.Decoders as Hasql
1827import qualified Hasql.Encoders as Hasql
19−import qualified Hasql.Session as Hasql
2028import qualified Hasql.Statement as Hasql
2129
30+-- opaleye
31+import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
32+import qualified Opaleye.Internal.HaskellDB.Sql as Opaleye
33+import qualified Opaleye.Internal.HaskellDB.Sql.Print as Opaleye
34+import qualified Opaleye.Internal.PrimQuery as Opaleye
35+import qualified Opaleye.Internal.Print as Opaleye
36+import qualified Opaleye.Internal.Optimize as Opaleye
37+import qualified Opaleye.Internal.QueryArr as Opaleye hiding ( Select )
38+import qualified Opaleye.Internal.Sql as Opaleye hiding ( Values )
39+import qualified Opaleye.Internal.Tag as Opaleye
40+
41+-- pretty
42+import Text.PrettyPrint ( Doc )
43+
2244-- rel8
45+import Rel8.Expr ( Expr )
46+import Rel8.Expr.Bool ( false )
47+import Rel8.Expr.Opaleye ( toPrimExpr )
2348import Rel8.Query ( Query )
24−import Rel8.Query.SQL ( sqlForQuery, sqlForQueryWithNames )
25−import Rel8.Table.Recontextualize ( Selects )
49+import Rel8.Query.Opaleye ( toOpaleye )
50+import Rel8.Schema.Name ( Selects )
51+import Rel8.Table ( Table )
52+import Rel8.Table.Cols ( toCols )
53+import Rel8.Table.Name ( namesFromLabels )
54+import Rel8.Table.Opaleye ( castTable, exprsWithNames )
55+import qualified Rel8.Table.Opaleye as T
2656import Rel8.Table.Serialize ( Serializable, parse )
57+import Rel8.Table.Undefined ( undefined )
2758
2859-- text
2960import qualified Data.Text as Text
3061import Data.Text.Encoding ( encodeUtf8 )
3162
3263
64+-- | Run a @SELECT@ statement, returning all rows.
3365select :: forall exprs a. Serializable exprs a
34− => Query exprs -> Connection -> IO [a]
35−select query = case sqlForQuery query of
36− Nothing -> const $ pure []
37− Just sql -> Hasql.run session >=> either throwIO pure
38− where
39− session = Hasql.statement () statement
40− statement = Hasql.Statement bytes params decode prepare
41− bytes = encodeUtf8 (Text.pack sql)
42− params = Hasql.noParams
43− decode = Hasql.rowList (parse @exprs @a)
44− prepare = False
45−
46−
47−selectWithNames :: forall exprs a names.
48− ( Selects names exprs
49− , Serializable exprs a
50− )
51− => names -> Query exprs -> Connection -> IO [a]
52−selectWithNames names query = case sqlForQueryWithNames names query of
53− Nothing -> const $ pure []
54− Just sql -> Hasql.run session >=> either throwIO pure
55− where
56− session = Hasql.statement () statement
57− statement = Hasql.Statement bytes params decode prepare
58− bytes = encodeUtf8 (Text.pack sql)
59− params = Hasql.noParams
60− decode = Hasql.rowList (parse @exprs @a)
61− prepare = False
66+ => Query exprs -> Hasql.Statement () [a]
67+select query = Hasql.Statement bytes params decode prepare
68+ where
69+ bytes = encodeUtf8 (Text.pack sql)
70+ params = Hasql.noParams
71+ decode = Hasql.rowList (parse @exprs @a)
72+ prepare = False
73+ sql = show doc
74+ doc = ppSelect query
75+
76+
77+ppSelect :: Table Expr a => Query a -> Doc
78+ppSelect query =
79+ Opaleye.ppSql $ primSelectWith names (toCols exprs') primQuery'
80+ where
81+ names = namesFromLabels
82+ (exprs, primQuery, _) =
83+ Opaleye.runSimpleQueryArrStart (toOpaleye query) ()
84+ (exprs', primQuery') = case optimize primQuery of
85+ Empty -> (undefined, Opaleye.Product (pure (pure Opaleye.Unit)) never)
86+ Unit -> (exprs, Opaleye.Unit)
87+ Optimized pq -> (exprs, pq)
88+ never = pure (toPrimExpr false)
89+
90+
91+ppRows :: Table Expr a => Query a -> Doc
92+ppRows query = case optimize primQuery of
93+ -- Special case VALUES because we can't use DEFAULT inside a SELECT
94+ Optimized (Opaleye.Values symbols rows)
95+ | eqSymbols symbols (toList (T.exprs a)) ->
96+ Opaleye.ppValues_ (map Opaleye.sqlExpr <$> toList rows)
97+ _ -> ppSelect query
98+ where
99+ (a, primQuery, _) = Opaleye.runSimpleQueryArrStart (toOpaleye query) ()
100+
101+ eqSymbols (symbol : symbols) (Opaleye.AttrExpr symbol' : exprs)
102+ | eqSymbol symbol symbol' = eqSymbols symbols exprs
103+ | otherwise = False
104+ eqSymbols [] [] = True
105+ eqSymbols _ _ = False
106+
107+ eqSymbol
108+ (Opaleye.Symbol name (Opaleye.UnsafeTag tag))
109+ (Opaleye.Symbol name' (Opaleye.UnsafeTag tag'))
110+ = name == name' && tag == tag'
111+
112+
113+ppPrimSelect :: Query a -> (Optimized Doc, a)
114+ppPrimSelect query =
115+ (Opaleye.ppSql . primSelect <$> optimize primQuery, a)
116+ where
117+ (a, primQuery, _) = Opaleye.runSimpleQueryArrStart (toOpaleye query) ()
118+
119+
120+type Optimized :: Type -> Type
121+data Optimized a = Empty | Unit | Optimized a
122+ deriving stock (Functor, Foldable, Traversable, Show)
123+
124+
125+optimize :: Opaleye.PrimQuery' a -> Optimized (Opaleye.PrimQuery' Void)
126+optimize query = case Opaleye.removeEmpty (Opaleye.optimize query) of
127+ Nothing -> Empty
128+ Just Opaleye.Unit -> Unit
129+ Just query' -> Optimized query'
130+
131+
132+primSelect :: Opaleye.PrimQuery' Void -> Opaleye.Select
133+primSelect = Opaleye.foldPrimQuery Opaleye.sqlQueryGenerator
134+
135+
136+primSelectWith :: Selects names exprs
137+ => names -> exprs -> Opaleye.PrimQuery' Void -> Opaleye.Select
138+primSelectWith names exprs query =
139+ Opaleye.SelectFrom $ Opaleye.newSelect
140+ { Opaleye.attrs = Opaleye.SelectAttrs attrs
141+ , Opaleye.tables = Opaleye.oneTable (primSelect query)
142+ }
143+ where
144+ attrs = makeAttr <$> exprsWithNames names (castTable exprs)
145+ where
146+ makeAttr (label, expr) =
147+ (Opaleye.sqlExpr expr, Just (Opaleye.SqlColumn label))
src/Rel8/Statement/Set.hsnew file+33
@@ -0,0 +1,33 @@
1+{-# language MonoLocalBinds #-}
2+{-# language NamedFieldPuns #-}
3+
4+module Rel8.Statement.Set
5+ ( ppSet
6+ )
7+where
8+
9+-- base
10+import Data.Foldable ( toList )
11+import Prelude ()
12+
13+-- opaleye
14+import qualified Opaleye.Internal.HaskellDB.Sql.Print as Opaleye
15+import qualified Opaleye.Internal.Sql as Opaleye
16+
17+-- pretty
18+import Text.PrettyPrint ( Doc, (<+>), equals, text )
19+
20+-- rel8
21+import Rel8.Schema.Name ( Selects, ppColumn )
22+import Rel8.Schema.Table ( TableSchema(..) )
23+import Rel8.Table.Opaleye ( attributes, exprsWithNames )
24+
25+
26+ppSet :: Selects names exprs
27+ => TableSchema names -> (exprs -> exprs) -> Doc
28+ppSet schema@TableSchema {columns} f =
29+ text "SET" <+> Opaleye.commaV ppAssign (toList assigns)
30+ where
31+ assigns = exprsWithNames columns (f (attributes schema))
32+ ppAssign (column, expr) =
33+ ppColumn column <+> equals <+> Opaleye.ppSqlExpr (Opaleye.sqlExpr expr)
src/Rel8/Statement/Update.hs+44−61
@@ -1,100 +1,83 @@
1+{-# language DuplicateRecordFields #-}
12{-# language GADTs #-}
23{-# language NamedFieldPuns #-}
3−{-# language ScopedTypeVariables #-}
4+{-# language RecordWildCards #-}
45{-# language StandaloneKindSignatures #-}
5−{-# language TypeApplications #-}
6+{-# language StrictData #-}
67
78module Rel8.Statement.Update
89 ( Update(..)
910 , update
11+ , ppUpdate
1012 )
1113where
1214
1315-- base
14−import Control.Exception ( throwIO )
15−import Control.Monad ( (>=>) )
1616import Data.Kind ( Type )
1717import Prelude
1818
1919-- hasql
20−import Hasql.Connection ( Connection )
21−import qualified Hasql.Decoders as Hasql
2220import qualified Hasql.Encoders as Hasql
23−import qualified Hasql.Session as Hasql
2421import qualified Hasql.Statement as Hasql
2522
26−-- opaleye
27−import qualified Opaleye.Internal.Manipulation as Opaleye
28−
29−-- profunctors
30−import Data.Profunctor ( lmap )
23+-- pretty
24+import Text.PrettyPrint ( Doc, (<+>), ($$), text )
3125
3226-- rel8
3327import Rel8.Expr ( Expr )
34−import Rel8.Expr.Opaleye ( toColumn, toPrimExpr )
35−import Rel8.Schema.Table ( TableSchema )
36−import Rel8.Statement.Returning ( Returning( Projection, NumberOfRowsAffected ) )
37−import Rel8.Table ( fromColumns, toColumns )
38−import Rel8.Table.Insert ( toInsert )
39−import Rel8.Table.Opaleye ( table, unpackspec )
40−import Rel8.Table.Recontextualize ( Selects )
41−import Rel8.Table.Serialize ( Serializable, parse )
28+import Rel8.Query ( Query )
29+import Rel8.Schema.Name ( Selects )
30+import Rel8.Schema.Table ( TableSchema(..), ppTable )
31+import Rel8.Statement.Returning ( Returning, decodeReturning, ppReturning )
32+import Rel8.Statement.Set ( ppSet )
33+import Rel8.Statement.Using ( ppFrom )
34+import Rel8.Statement.Where ( ppWhere )
4235
4336-- text
4437import qualified Data.Text as Text
4538import Data.Text.Encoding ( encodeUtf8 )
4639
4740
41+-- | The constituent parts of an @UPDATE@ statement.
4842type Update :: Type -> Type
4943data Update a where
5044 Update :: Selects names exprs =>
5145 { target :: TableSchema names
52− , set :: exprs -> exprs
53− , updateWhere :: exprs -> Expr Bool
46+ -- ^ Which table to update.
47+ , from :: Query from
48+ -- ^ @FROM@ clause — this can be used to join against other tables,
49+ -- and its results can be referenced in the @SET@ and @WHERE@ clauses.
50+ , set :: from -> exprs -> exprs
51+ -- ^ How to update each selected row.
52+ , updateWhere :: from -> exprs -> Expr Bool
53+ -- ^ Which rows to select for update.
5454 , returning :: Returning names a
55+ -- ^ What to return from the @UPDATE@ statement.
5556 }
5657 -> Update a
5758
5859
59−update :: Update a -> Connection -> IO a
60−update Update {target, set, updateWhere, returning} =
61− case returning of
62− NumberOfRowsAffected -> Hasql.run session >=> either throwIO pure
63− where
64− session = Hasql.statement () statement
65− statement = Hasql.Statement bytes params decode prepare
66− bytes = encodeUtf8 $ Text.pack sql
67− params = Hasql.noParams
68− decode = Hasql.rowsAffected
69− prepare = False
70− sql = Opaleye.arrangeUpdateSql target' set' where'
71− where
72− target' = lmap toInsert $ table $ toColumns <$> target
73− set' = toColumns . set . fromColumns
74− where' = toColumn . toPrimExpr . updateWhere . fromColumns
60+ppUpdate :: Update a -> Doc
61+ppUpdate Update {..} = case ppFrom from of
62+ Nothing ->
63+ text "UPDATE" <+> ppTable target $$
64+ ppSet target id $$
65+ text "WHERE false"
66+ Just (fromDoc, i) ->
67+ text "UPDATE" <+> ppTable target $$
68+ ppSet target (set i) $$
69+ fromDoc $$
70+ ppWhere target (updateWhere i) $$
71+ ppReturning target returning
7572
76− Projection project -> Hasql.run session >=> either throwIO pure
77− where
78− session = Hasql.statement () statement
79− statement = Hasql.Statement bytes params decode prepare
80− bytes = encodeUtf8 $ Text.pack sql
81− params = Hasql.noParams
82− decode = decoder project
83− prepare = False
84− sql =
85− Opaleye.arrangeUpdateReturningSql
86− unpackspec
87− target'
88− set'
89− where'
90− project'
91− where
92− target' = lmap toInsert $ table $ toColumns <$> target
93− set' = toColumns . set . fromColumns
94− where' = toColumn . toPrimExpr . updateWhere . fromColumns
95− project' = toColumns . project . fromColumns
9673
74+-- | Run an @UPDATE@ statement.
75+update :: Update a -> Hasql.Statement () a
76+update u@Update {returning} = Hasql.Statement bytes params decode prepare
9777 where
98− decoder :: forall exprs projection a. Serializable projection a
99− => (exprs -> projection) -> Hasql.Result [a]
100− decoder _ = Hasql.rowList (parse @projection @a)
78+ bytes = encodeUtf8 $ Text.pack sql
79+ params = Hasql.noParams
80+ decode = decodeReturning returning
81+ prepare = False
82+ sql = show doc
83+ doc = ppUpdate u
src/Rel8/Statement/Using.hsnew file+36
@@ -0,0 +1,36 @@
1+module Rel8.Statement.Using
2+ ( ppFrom
3+ , ppUsing
4+ )
5+where
6+
7+-- base
8+import Prelude
9+
10+-- pretty
11+import Text.PrettyPrint ( Doc, (<+>), parens, text )
12+
13+-- rel8
14+import Rel8.Query ( Query )
15+import Rel8.Schema.Table ( TableSchema(..), ppTable )
16+import Rel8.Statement.Select ( Optimized(..), ppPrimSelect )
17+
18+
19+ppFrom :: Query a -> Maybe (Doc, a)
20+ppFrom = ppJoin "FROM"
21+
22+
23+ppUsing :: Query a -> Maybe (Doc, a)
24+ppUsing = ppJoin "USING"
25+
26+
27+ppJoin :: String -> Query a -> Maybe (Doc, a)
28+ppJoin clause join = do
29+ doc <- case ofrom of
30+ Empty -> Nothing
31+ Unit -> Just mempty
32+ Optimized doc -> Just $ text clause <+> parens doc <+> ppTable alias
33+ pure (doc, a)
34+ where
35+ alias = TableSchema {name = "T1", schema = Nothing, columns = ()}
36+ (ofrom, a) = ppPrimSelect join
src/Rel8/Statement/View.hs+48−29
@@ -1,59 +1,78 @@
11{-# language FlexibleContexts #-}
2+{-# language MonoLocalBinds #-}
23
34module Rel8.Statement.View
45 ( createView
6+ , createOrReplaceView
57 )
68where
79
810-- base
9−import Control.Exception ( throwIO )
10−import Control.Monad ( (>=>) )
11−import Data.Foldable ( fold )
12−import Data.Maybe ( fromMaybe )
1311import Prelude
1412
1513-- hasql
16−import Hasql.Connection ( Connection )
1714import qualified Hasql.Decoders as Hasql
1815import qualified Hasql.Encoders as Hasql
19−import qualified Hasql.Session as Hasql
2016import qualified Hasql.Statement as Hasql
2117
2218-- rel8
2319import Rel8.Query ( Query )
24−import Rel8.Query.SQL ( sqlForQueryWithNames )
25−import Rel8.Schema.Table ( TableSchema( TableSchema ) )
26−import Rel8.Table.Alternative ( emptyTable )
27−import Rel8.Table.Recontextualize ( Selects )
20+import Rel8.Schema.Name ( Selects )
21+import Rel8.Schema.Table ( TableSchema )
22+import Rel8.Statement.Insert ( ppInto )
23+import Rel8.Statement.Select ( ppSelect )
24+
25+-- pretty
26+import Text.PrettyPrint ( Doc, (<+>), ($$), text )
2827
2928-- text
3029import qualified Data.Text as Text
3130import Data.Text.Encoding ( encodeUtf8 )
3231
3332
33+data CreateView = Create | CreateOrReplace
34+
35+
36+-- | Given a 'TableSchema' and 'Query', @createView@ runs a @CREATE VIEW@
37+-- statement that will save the given query as a view. This can be useful if
38+-- you want to share Rel8 queries with other applications.
3439createView :: Selects names exprs
35− => TableSchema names -> Query exprs -> Connection -> IO ()
36−createView (TableSchema name mschema names) query =
37− Hasql.run session >=> either throwIO pure
40+ => TableSchema names -> Query exprs -> Hasql.Statement () ()
41+createView =
42+ createViewGeneric Create
43+
44+
45+-- | Given a 'TableSchema' and 'Query', @createOrReplaceView@ runs a
46+-- @CREATE OR REPLACE VIEW@ statement that will save the given query
47+-- as a view, replacing the current view definition if it exists and
48+-- adheres to the restrictions in place for replacing a view in
49+-- PostgreSQL.
50+createOrReplaceView :: Selects names exprs
51+ => TableSchema names -> Query exprs -> Hasql.Statement () ()
52+createOrReplaceView =
53+ createViewGeneric CreateOrReplace
54+
55+
56+createViewGeneric :: Selects names exprs
57+ => CreateView -> TableSchema names -> Query exprs -> Hasql.Statement () ()
58+createViewGeneric replace schema query =
59+ Hasql.Statement bytes params decode prepare
3860 where
39− session = Hasql.statement () statement
40− statement = Hasql.Statement bytes params decode prepare
4161 bytes = encodeUtf8 (Text.pack sql)
4262 params = Hasql.noParams
4363 decode = Hasql.noResult
4464 prepare = False
45− sql = "CREATE VIEW " <> title <> " WITH " <> select
46− where
47− title = case mschema of
48− Nothing -> quote name
49− Just schema -> quote schema <> "." <> quote name
50− select = fromMaybe fallback $ sqlForQueryWithNames names query
51− where
52− fallback = fold $ sqlForQueryWithNames names emptyTable
53−
54−
55−quote :: String -> String
56−quote string = "\"" <> concatMap go string <> "\""
65+ sql = show doc
66+ doc = ppCreateView schema query replace
67+
68+
69+ppCreateView :: Selects names exprs
70+ => TableSchema names -> Query exprs -> CreateView -> Doc
71+ppCreateView schema query replace =
72+ createOrReplace replace <+>
73+ ppInto schema $$
74+ text "AS" <+>
75+ ppSelect query
5776 where
58− go '"' = "\"\""
59− go c = [c]
77+ createOrReplace Create = text "CREATE VIEW"
78+ createOrReplace CreateOrReplace = text "CREATE OR REPLACE VIEW"
src/Rel8/Statement/Where.hsnew file+31
@@ -0,0 +1,31 @@
1+{-# language MonoLocalBinds #-}
2+
3+module Rel8.Statement.Where
4+ ( ppWhere
5+ )
6+where
7+
8+-- base
9+import Prelude
10+
11+-- opaleye
12+import qualified Opaleye.Internal.HaskellDB.Sql.Print as Opaleye
13+import qualified Opaleye.Internal.Sql as Opaleye
14+
15+-- pretty
16+import Text.PrettyPrint ( Doc, (<+>), text )
17+
18+-- rel8
19+import Rel8.Expr ( Expr )
20+import Rel8.Expr.Opaleye ( toPrimExpr )
21+import Rel8.Schema.Name ( Selects )
22+import Rel8.Schema.Table ( TableSchema )
23+import Rel8.Table.Opaleye ( attributes )
24+
25+
26+ppWhere :: Selects names exprs
27+ => TableSchema names -> (exprs -> Expr Bool) -> Doc
28+ppWhere schema where_ = text "WHERE" <+> ppExpr condition
29+ where
30+ ppExpr = Opaleye.ppSqlExpr . Opaleye.sqlExpr . toPrimExpr
31+ condition = where_ (attributes schema)
src/Rel8/Table.hs+159−160
@@ -1,221 +1,220 @@
1+{-# language AllowAmbiguousTypes #-}
12{-# language DataKinds #-}
2−{-# language DisambiguateRecordFields #-}
3+{-# language DefaultSignatures #-}
34{-# language FlexibleContexts #-}
45{-# language FlexibleInstances #-}
56{-# language FunctionalDependencies #-}
7+{-# language ScopedTypeVariables #-}
68{-# language StandaloneKindSignatures #-}
9+{-# language TypeApplications #-}
710{-# language TypeFamilies #-}
811{-# language UndecidableInstances #-}
912
1013module Rel8.Table
11− ( Table (Columns, Context)
12− , toColumns, fromColumns
14+ ( Table
15+ ( Columns, Context, fromColumns, toColumns
16+ , FromExprs, fromResult, toResult
17+ , Transpose
18+ )
1319 , Congruent
20+ , TTable, TColumns, TContext, TFromExprs, TTranspose
21+ , TSerialize
1422 )
1523where
1624
1725-- base
1826import Data.Functor.Identity ( Identity( Identity ) )
1927import Data.Kind ( Constraint, Type )
20−import Prelude
28+import GHC.Generics ( Generic, Rep, from, to )
29+import Prelude hiding ( null )
2130
2231-- rel8
23−import Rel8.Aggregate ( Aggregate )
24−import Rel8.Expr ( Expr )
25−import Rel8.Opaque ( Opaque, Opaque1 )
26−import Rel8.Schema.Context
27− ( Aggregation( Aggregation )
28− , DB( DB ), unDB
29− , Result( Result )
32+import Rel8.FCF ( Eval, Exp )
33+import Rel8.Generic.Map ( Map )
34+import Rel8.Generic.Table.Record
35+ ( GTable, GColumns, GContext, gfromColumns, gtoColumns
36+ , GSerialize, gfromResult, gtoResult
3037 )
31−import Rel8.Schema.Context.Label ( Labelable, labeler, unlabeler )
32−import Rel8.Schema.HTable ( HTable, hfield, hspecs, htabulate, htabulateA )
33−import Rel8.Schema.HTable.Context ( H, HKTable )
34−import Rel8.Schema.HTable.Identity ( HIdentity(..) )
35−import Rel8.Schema.HTable.Label ( HLabel, hlabel, hunlabel )
36−import Rel8.Schema.HTable.Pair ( HPair(..) )
37−import Rel8.Schema.HTable.Quartet ( HQuartet(..) )
38−import Rel8.Schema.HTable.Quintet ( HQuintet(..) )
39−import Rel8.Schema.HTable.Trio ( HTrio(..) )
40−import Rel8.Schema.HTable.Type ( HType( HType ) )
41−import Rel8.Schema.Nullability ( Nullabilizes )
42−import Rel8.Schema.Spec ( SSpec( SSpec ), KnownSpec )
43−import qualified Rel8.Schema.Spec as Kind ( Context )
38+import Rel8.Generic.Record ( Record(..) )
39+import Rel8.Schema.HTable ( HTable )
40+import Rel8.Schema.HTable.Identity ( HIdentity( HIdentity ) )
41+import qualified Rel8.Schema.Kind as K
42+import Rel8.Schema.Null ( Sql )
43+import Rel8.Schema.Result ( Result )
4444import Rel8.Type ( DBType )
4545
4646
47−type Table :: Kind.Context -> Type -> Constraint
48−class (HTable (Columns a), context ~ Context a) => Table context a | a -> context where
49− type Columns a :: HKTable
50− type Context a :: Kind.Context
47+-- | @Table@s are one of the foundational elements of Rel8, and describe data
48+-- types that have a finite number of columns. Each of these columns contains
49+-- data under a shared context, and contexts describe how to interpret the
50+-- metadata about a column to a particular Haskell type. In Rel8, we have
51+-- contexts for expressions (the 'Rel8.Expr' context), aggregations (the
52+-- 'Rel8.Aggregate' context), insert values (the 'Rel8.Insert' contex), among
53+-- others.
54+--
55+-- In typical usage of Rel8 you don't need to derive instances of 'Table'
56+-- yourself, as anything that's an instance of 'Rel8.Rel8able' is always a
57+-- 'Table'.
58+type Table :: K.Context -> Type -> Constraint
59+class
60+ ( HTable (Columns a)
61+ , context ~ Context a
62+ , a ~ Transpose context a
63+ )
64+ => Table context a | a -> context
65+ where
66+ -- | The 'HTable' functor that describes the schema of this table.
67+ type Columns a :: K.HTable
68+
69+ -- | The common context that all columns use as an interpretation.
70+ type Context a :: K.Context
5171
52− toColumns :: a -> Columns a (H (Context a))
53− fromColumns :: Columns a (H (Context a)) -> a
72+ -- | The @FromExprs@ type family maps a type in the @Expr@ context to the
73+ -- corresponding Haskell type.
74+ type FromExprs a :: Type
5475
76+ type Transpose (context' :: K.Context) a :: Type
5577
56−-- | Any 'HTable' is also a 'Table'.
57−instance HTable t => Table context (t (H context)) where
58− type Columns (t (H context)) = t
59− type Context (t (H context)) = context
6078
61− toColumns = id
62− fromColumns = id
79+ toColumns :: a -> Columns a context
80+ fromColumns :: Columns a context -> a
6381
82+ fromResult :: Columns a Result -> FromExprs a
83+ toResult :: FromExprs a -> Columns a Result
6484
65−-- | Any context is trivially a table.
66−instance KnownSpec spec => Table context (context spec) where
67− type Columns (context spec) = HIdentity spec
68− type Context (context spec) = context
85+ type Columns a = GColumns TColumns (Rep (Record a))
86+ type Context a = GContext TContext (Rep (Record a))
87+ type FromExprs a = Map TFromExprs a
88+ type Transpose context a = Map (TTranspose context) a
89+
90+ default toColumns ::
91+ ( Generic (Record a)
92+ , GTable (TTable context) TColumns (Rep (Record a))
93+ , Columns a ~ GColumns TColumns (Rep (Record a))
94+ )
95+ => a -> Columns a context
96+ toColumns =
97+ gtoColumns @(TTable context) @TColumns toColumns .
98+ from .
99+ Record
100+
101+ default fromColumns ::
102+ ( Generic (Record a)
103+ , GTable (TTable context) TColumns (Rep (Record a))
104+ , Columns a ~ GColumns TColumns (Rep (Record a))
105+ )
106+ => Columns a context -> a
107+ fromColumns =
108+ unrecord .
109+ to .
110+ gfromColumns @(TTable context) @TColumns fromColumns
111+
112+ default toResult ::
113+ ( Generic (Record (FromExprs a))
114+ , GSerialize TSerialize TColumns (Rep (Record a)) (Rep (Record (FromExprs a)))
115+ , Columns a ~ GColumns TColumns (Rep (Record a))
116+ )
117+ => FromExprs a -> Columns a Result
118+ toResult =
119+ gtoResult
120+ @TSerialize
121+ @TColumns
122+ @(Rep (Record a))
123+ @(Rep (Record (FromExprs a)))
124+ (\(_ :: proxy x) -> toResult @(Context x) @x) .
125+ from .
126+ Record
127+
128+ default fromResult ::
129+ ( Generic (Record (FromExprs a))
130+ , GSerialize TSerialize TColumns (Rep (Record a)) (Rep (Record (FromExprs a)))
131+ , Columns a ~ GColumns TColumns (Rep (Record a))
132+ )
133+ => Columns a Result -> FromExprs a
134+ fromResult =
135+ unrecord .
136+ to .
137+ gfromResult
138+ @TSerialize
139+ @TColumns
140+ @(Rep (Record a))
141+ @(Rep (Record (FromExprs a)))
142+ (\(_ :: proxy x) -> fromResult @(Context x) @x)
143+
144+
145+instance Sql DBType a => Table Result (Identity a) where
146+ type Columns (Identity a) = HIdentity a
147+ type Context (Identity a) = Result
148+ type FromExprs (Identity a) = a
149+ type Transpose to (Identity a) = to a
69150
70151 toColumns = HIdentity
71− fromColumns = unHIdentity
152+ fromColumns (HIdentity a) = a
153+ toResult a = HIdentity (Identity a)
154+ fromResult (HIdentity (Identity a)) = a
72155
73156
74−instance Table DB a => Table Aggregation (Aggregate a) where
75− type Columns (Aggregate a) = Columns a
76− type Context (Aggregate a) = Aggregation
157+data TTable :: K.Context -> Type -> Exp Constraint
158+type instance Eval (TTable context a) = Table context a
77159
78− toColumns a = htabulate $ \field -> case hfield hspecs field of
79− SSpec {} -> Aggregation $ unDB . (`hfield` field) . toColumns <$> a
80− fromColumns as = fmap fromColumns $ htabulateA $ \field ->
81− case hfield as field of
82− Aggregation a -> DB <$> a
83160
161+data TColumns :: Type -> Exp K.HTable
162+type instance Eval (TColumns a) = Columns a
84163
85−instance (DBType db, Nullabilizes db a) => Table DB (Expr a) where
86− type Columns (Expr a) = HType a
87− type Context (Expr a) = DB
88164
89− toColumns a = HType (DB a)
90− fromColumns (HType (DB a)) = a
165+data TContext :: Type -> Exp K.Context
166+type instance Eval (TContext a) = Context a
91167
92168
93−instance (DBType db, Nullabilizes db a) => Table Result (Identity a) where
94− type Columns (Identity a) = HType a
95− type Context (Identity a) = Result
169+data TFromExprs :: Type -> Exp Type
170+type instance Eval (TFromExprs a) = FromExprs a
96171
97− toColumns (Identity a) = HType (Result a)
98− fromColumns (HType (Result a)) = Identity a
99172
173+data TTranspose :: K.Context -> Type -> Exp Type
174+type instance Eval (TTranspose context a) = Transpose context a
100175
101−instance
102− ( Table context a, Table context b
103− , Labelable context
104− ) =>
105− Table context (a, b)
106− where
107− type Columns (a, b) =
108− HPair
109− (HLabel "fst" (Columns a))
110− (HLabel "snd" (Columns b))
111− type Context (a, b) = Context a
112−
113− toColumns (a, b) = HPair
114− { hfst = hlabel labeler $ toColumns a
115− , hsnd = hlabel labeler $ toColumns b
116− }
117− fromColumns (HPair a b) =
118− ( fromColumns $ hunlabel unlabeler a
119− , fromColumns $ hunlabel unlabeler b
120− )
176+
177+data TSerialize :: Type -> Type -> Exp Constraint
178+type instance Eval (TSerialize expr a) =
179+ ( Table (Context expr) expr
180+ , a ~ FromExprs expr
181+ )
182+
183+
184+instance (Table context a, Table context b) => Table context (a, b)
121185
122186
123187instance
124188 ( Table context a, Table context b, Table context c
125− , Labelable context
126− ) => Table context (a, b, c)
127− where
128− type Columns (a, b, c) =
129− HTrio
130− (HLabel "fst" (Columns a))
131− (HLabel "snd" (Columns b))
132− (HLabel "trd" (Columns c))
133− type Context (a, b, c) = Context a
134−
135− toColumns (a, b, c) = HTrio
136− { hfst = hlabel labeler $ toColumns a
137− , hsnd = hlabel labeler $ toColumns b
138− , htrd = hlabel labeler $ toColumns c
139− }
140− fromColumns (HTrio a b c) =
141− ( fromColumns $ hunlabel unlabeler a
142− , fromColumns $ hunlabel unlabeler b
143− , fromColumns $ hunlabel unlabeler c
144− )
189+ )
190+ => Table context (a, b, c)
145191
146192
147193instance
148194 ( Table context a, Table context b, Table context c, Table context d
149− , Labelable context
150− ) => Table context (a, b, c, d)
151− where
152− type Columns (a, b, c, d) =
153− HQuartet
154− (HLabel "fst" (Columns a))
155− (HLabel "snd" (Columns b))
156− (HLabel "trd" (Columns c))
157− (HLabel "frt" (Columns d))
158− type Context (a, b, c, d) = Context a
159−
160− toColumns (a, b, c, d) = HQuartet
161− { hfst = hlabel labeler $ toColumns a
162− , hsnd = hlabel labeler $ toColumns b
163− , htrd = hlabel labeler $ toColumns c
164− , hfrt = hlabel labeler $ toColumns d
165− }
166− fromColumns (HQuartet a b c d) =
167− ( fromColumns $ hunlabel unlabeler a
168− , fromColumns $ hunlabel unlabeler b
169− , fromColumns $ hunlabel unlabeler c
170− , fromColumns $ hunlabel unlabeler d
171− )
195+ )
196+ => Table context (a, b, c, d)
172197
173198
174199instance
175200 ( Table context a, Table context b, Table context c, Table context d
176201 , Table context e
177− , Labelable context
178− ) => Table context (a, b, c, d, e)
179− where
180− type Columns (a, b, c, d, e) =
181− HQuintet
182− (HLabel "fst" (Columns a))
183− (HLabel "snd" (Columns b))
184− (HLabel "trd" (Columns c))
185− (HLabel "frt" (Columns d))
186− (HLabel "fft" (Columns e))
187− type Context (a, b, c, d, e) = Context a
188−
189− toColumns (a, b, c, d, e) = HQuintet
190− { hfst = hlabel labeler $ toColumns a
191− , hsnd = hlabel labeler $ toColumns b
192− , htrd = hlabel labeler $ toColumns c
193− , hfrt = hlabel labeler $ toColumns d
194− , hfft = hlabel labeler $ toColumns e
195− }
196− fromColumns (HQuintet a b c d e) =
197− ( fromColumns $ hunlabel unlabeler a
198− , fromColumns $ hunlabel unlabeler b
199− , fromColumns $ hunlabel unlabeler c
200− , fromColumns $ hunlabel unlabeler d
201− , fromColumns $ hunlabel unlabeler e
202− )
203−
204−
205−instance Table DB Opaque where
206− type Columns Opaque = HType Opaque
207− type Context Opaque = DB
202+ )
203+ => Table context (a, b, c, d, e)
208204
209− fromColumns = error "opaque"
210− toColumns = error "opaque"
211205
206+instance
207+ ( Table context a, Table context b, Table context c, Table context d
208+ , Table context e, Table context f
209+ )
210+ => Table context (a, b, c, d, e, f)
212211
213−instance Table context (Opaque1 context a) where
214− type Columns (Opaque1 context a) = HType Opaque
215− type Context (Opaque1 context a) = context
216212
217− fromColumns = error "opaque"
218− toColumns = error "opaque"
213+instance
214+ ( Table context a, Table context b, Table context c, Table context d
215+ , Table context e, Table context f, Table context g
216+ )
217+ => Table context (a, b, c, d, e, f, g)
219218
220219
221220type Congruent :: Type -> Type -> Constraint
src/Rel8/Table/ADT.hsnew file+173
@@ -0,0 +1,173 @@
1+{-# language AllowAmbiguousTypes #-}
2+{-# language DataKinds #-}
3+{-# language FlexibleContexts #-}
4+{-# language FlexibleInstances #-}
5+{-# language MultiParamTypeClasses #-}
6+{-# language RankNTypes #-}
7+{-# language ScopedTypeVariables #-}
8+{-# language StandaloneKindSignatures #-}
9+{-# language TypeApplications #-}
10+{-# language TypeFamilyDependencies #-}
11+{-# language UndecidableInstances #-}
12+{-# language UndecidableSuperClasses #-}
13+
14+module Rel8.Table.ADT
15+ ( ADT( ADT )
16+ , ADTable
17+ , BuildableADT
18+ , BuildADT, buildADT
19+ , ConstructableADT
20+ , ConstructADT, constructADT
21+ , DeconstructADT, deconstructADT
22+ , NameADT, nameADT
23+ , AggregateADT, aggregateADT
24+ , ADTRep
25+ )
26+where
27+
28+-- base
29+import Data.Kind ( Constraint, Type )
30+import GHC.Generics ( Generic, from, to )
31+import GHC.TypeLits ( Symbol )
32+import Prelude
33+
34+-- rel8
35+import Rel8.Aggregate ( Aggregate )
36+import Rel8.Expr ( Expr )
37+import Rel8.FCF ( Eval, Exp )
38+import Rel8.Generic.Construction
39+ ( GGBuildable
40+ , GGBuild, ggbuild
41+ , GGConstructable
42+ , GGConstruct, ggconstruct
43+ , GGDeconstruct, ggdeconstruct
44+ , GGName, ggname
45+ , GGAggregate, ggaggregate
46+ )
47+import Rel8.Generic.Record ( Record( Record ), unrecord )
48+import Rel8.Generic.Rel8able
49+ ( Rel8able
50+ , GRep, GColumns, gfromColumns, gtoColumns
51+ , GFromExprs, gfromResult, gtoResult
52+ , TSerialize, deserialize, serialize
53+ )
54+import qualified Rel8.Generic.Table.ADT as G
55+import qualified Rel8.Kind.Algebra as K
56+import Rel8.Schema.HTable ( HTable )
57+import qualified Rel8.Schema.Kind as K
58+import Rel8.Schema.Name ( Name )
59+import Rel8.Schema.Result ( Result )
60+import Rel8.Table ( Table, TColumns )
61+
62+
63+type ADT :: K.Rel8able -> K.Rel8able
64+newtype ADT t context = ADT (GColumnsADT t context)
65+
66+
67+instance ADTable t => Rel8able (ADT t) where
68+ type GColumns (ADT t) = GColumnsADT t
69+ type GFromExprs (ADT t) = t Result
70+
71+ gfromColumns _ = ADT
72+ gtoColumns _ (ADT a) = a
73+
74+ gfromResult =
75+ unrecord .
76+ to .
77+ G.gfromResultADT
78+ @TSerialize
79+ @TColumns
80+ @(Eval (ADTRep t Expr))
81+ @(Eval (ADTRep t Result))
82+ (\(_ :: proxy x) -> deserialize @_ @x)
83+
84+ gtoResult =
85+ G.gtoResultADT
86+ @TSerialize
87+ @TColumns
88+ @(Eval (ADTRep t Expr))
89+ @(Eval (ADTRep t Result))
90+ (\(_ :: proxy x) -> serialize @_ @x) .
91+ from .
92+ Record
93+
94+
95+type ADTable :: K.Rel8able -> Constraint
96+class
97+ ( Generic (Record (t Result))
98+ , HTable (GColumnsADT t)
99+ , G.GSerializeADT TSerialize TColumns (Eval (ADTRep t Expr)) (Eval (ADTRep t Result))
100+ )
101+ => ADTable t
102+instance
103+ ( Generic (Record (t Result))
104+ , HTable (GColumnsADT t)
105+ , G.GSerializeADT TSerialize TColumns (Eval (ADTRep t Expr)) (Eval (ADTRep t Result))
106+ )
107+ => ADTable t
108+
109+
110+type BuildableADT :: K.Rel8able -> Symbol -> Constraint
111+class GGBuildable 'K.Sum name (ADTRep t) => BuildableADT t name
112+instance GGBuildable 'K.Sum name (ADTRep t) => BuildableADT t name
113+
114+
115+type BuildADT :: K.Rel8able -> Symbol -> Type
116+type BuildADT t name = GGBuild 'K.Sum name (ADTRep t) (ADT t Expr)
117+
118+
119+buildADT :: forall t name. BuildableADT t name => BuildADT t name
120+buildADT =
121+ ggbuild @'K.Sum @name @(ADTRep t) @(ADT t Expr) ADT
122+
123+
124+type ConstructableADT :: K.Rel8able -> Constraint
125+class GGConstructable 'K.Sum (ADTRep t) => ConstructableADT t
126+instance GGConstructable 'K.Sum (ADTRep t) => ConstructableADT t
127+
128+
129+type ConstructADT :: K.Rel8able -> Type
130+type ConstructADT t = forall r. GGConstruct 'K.Sum (ADTRep t) r
131+
132+
133+constructADT :: forall t. ConstructableADT t => ConstructADT t -> ADT t Expr
134+constructADT f =
135+ ggconstruct @'K.Sum @(ADTRep t) @(ADT t Expr) ADT
136+ (f @(ADT t Expr))
137+
138+
139+type DeconstructADT :: K.Rel8able -> Type -> Type
140+type DeconstructADT t r = GGDeconstruct 'K.Sum (ADTRep t) (ADT t Expr) r
141+
142+
143+deconstructADT :: forall t r. (ConstructableADT t, Table Expr r)
144+ => DeconstructADT t r
145+deconstructADT =
146+ ggdeconstruct @'K.Sum @(ADTRep t) @(ADT t Expr) @r (\(ADT a) -> a)
147+
148+
149+type NameADT :: K.Rel8able -> Type
150+type NameADT t = GGName 'K.Sum (ADTRep t) (ADT t Name)
151+
152+
153+nameADT :: forall t. ConstructableADT t => NameADT t
154+nameADT = ggname @'K.Sum @(ADTRep t) @(ADT t Name) ADT
155+
156+
157+type AggregateADT :: K.Rel8able -> Type
158+type AggregateADT t = forall r. GGAggregate 'K.Sum (ADTRep t) r
159+
160+
161+aggregateADT :: forall t. ConstructableADT t
162+ => AggregateADT t -> ADT t Expr -> ADT t Aggregate
163+aggregateADT f =
164+ ggaggregate @'K.Sum @(ADTRep t) @(ADT t Expr) @(ADT t Aggregate) ADT (\(ADT a) -> a)
165+ (f @(ADT t Aggregate))
166+
167+
168+data ADTRep :: K.Rel8able -> K.Context -> Exp (Type -> Type)
169+type instance Eval (ADTRep t context) = GRep t context
170+
171+
172+type GColumnsADT :: K.Rel8able -> K.HTable
173+type GColumnsADT t = G.GColumnsADT TColumns (GRep t Expr)
src/Rel8/Table/Aggregate.hs+59−29
@@ -6,10 +6,8 @@
66{-# language ViewPatterns #-}
77
88module Rel8.Table.Aggregate
9− ( groupBy
10− , listAgg
11− , nonEmptyAgg
12− , runAggregation
9+ ( groupBy, hgroupBy
10+ , listAgg, nonEmptyAgg
1311 )
1412where
1513
@@ -18,45 +16,77 @@ import Data.Functor.Identity ( Identity( Identity ) )
1816import Prelude
1917
2018-- rel8
21−import Rel8.Aggregate ( Aggregate )
22−import Rel8.Expr.Aggregate ( listAggExpr, nonEmptyAggExpr, sgroupByExpr )
23−import Rel8.Schema.Context ( Aggregation( Aggregation ), DB( DB ) )
19+import Rel8.Aggregate ( Aggregate, Aggregates )
20+import Rel8.Expr ( Expr )
21+import Rel8.Expr.Aggregate
22+ ( groupByExpr
23+ , slistAggExpr
24+ , snonEmptyAggExpr
25+ )
2426import Rel8.Schema.Dict ( Dict( Dict ) )
25−import Rel8.Schema.HTable ( htabulate, hfield, hdicts, hspecs )
27+import Rel8.Schema.HTable ( HTable, hfield, htabulate )
2628import Rel8.Schema.HTable.Vectorize ( hvectorize )
27−import Rel8.Schema.Spec ( SSpec(..) )
28−import Rel8.Schema.Spec.ConstrainDBType ( ConstrainDBType )
29−import Rel8.Table ( Table, Columns, toColumns, fromColumns )
30−import Rel8.Table.Eq ( EqTable )
29+import Rel8.Schema.Null ( Sql )
30+import Rel8.Schema.Spec ( Spec( Spec, info ) )
31+import Rel8.Table ( toColumns, fromColumns )
32+import Rel8.Table.Eq ( EqTable, eqTable )
3133import Rel8.Table.List ( ListTable )
3234import Rel8.Table.NonEmpty ( NonEmptyTable )
33−import Rel8.Table.Recontextualize ( Aggregates )
3435import Rel8.Type.Eq ( DBEq )
3536
3637
37−groupBy :: forall exprs. EqTable exprs => exprs -> Aggregate exprs
38−groupBy (toColumns -> exprs) = fromColumns $ htabulate $ \field ->
39− case hfield dicts field of
40− Dict -> case hfield hspecs field of
41− SSpec {nullability} -> case hfield exprs field of
42− DB expr -> Aggregation $ sgroupByExpr nullability expr
43− where
44− dicts = hdicts @(Columns exprs) @(ConstrainDBType DBEq)
38+-- | Group equal tables together. This works by aggregating each column in the
39+-- given table with 'groupByExpr'.
40+--
41+-- For example, if we have a table of items, we could group the items by the
42+-- order they belong to:
43+--
44+-- @
45+-- itemsByOrder :: Query (OrderId Expr, ListTable Expr (Item Expr))
46+-- itemsByOrder = aggregate $ do
47+-- item <- each itemSchema
48+-- let orderId = groupBy (itemOrderId item)
49+-- let orderItems = listAgg item
50+-- pure (orderId, orderItems)
51+-- @
52+groupBy :: forall exprs aggregates. (EqTable exprs, Aggregates aggregates exprs)
53+ => exprs -> aggregates
54+groupBy = fromColumns . hgroupBy (eqTable @exprs) . toColumns
55+
56+
57+hgroupBy :: HTable t => t (Dict (Sql DBEq)) -> t Expr -> t Aggregate
58+hgroupBy eqs exprs = htabulate $ \field ->
59+ case hfield eqs field of
60+ Dict -> case hfield exprs field of
61+ expr -> groupByExpr expr
4562
4663
47−listAgg :: Table DB exprs => exprs -> Aggregate (ListTable exprs)
64+-- | Aggregate rows into a single row containing an array of all aggregated
65+-- rows. This can be used to associate multiple rows with a single row, without
66+-- changing the over cardinality of the query. This allows you to essentially
67+-- return a tree-like structure from queries.
68+--
69+-- For example, if we have a table of orders and each orders contains multiple
70+-- items, we could aggregate the table of orders, pairing each order with its
71+-- items:
72+--
73+-- @
74+-- ordersWithItems :: Query (Order Expr, ListTable Expr (Item Expr))
75+-- ordersWithItems = do
76+-- order <- each orderSchema
77+-- items <- aggregate $ listAgg <$> itemsFromOrder order
78+-- return (order, items)
79+-- @
80+listAgg :: Aggregates aggregates exprs => exprs -> ListTable Aggregate aggregates
4881listAgg (toColumns -> exprs) = fromColumns $
4982 hvectorize
50− (\_ (Identity (DB a)) -> Aggregation $ listAggExpr a)
83+ (\Spec {info} (Identity a) -> slistAggExpr info a)
5184 (pure exprs)
5285
5386
54−nonEmptyAgg :: Table DB exprs => exprs -> Aggregate (NonEmptyTable exprs)
87+-- | Like 'listAgg', but the result is guaranteed to be a non-empty list.
88+nonEmptyAgg :: Aggregates aggregates exprs => exprs -> NonEmptyTable Aggregate aggregates
5589nonEmptyAgg (toColumns -> exprs) = fromColumns $
5690 hvectorize
57− (\_ (Identity (DB a)) -> Aggregation $ nonEmptyAggExpr a)
91+ (\Spec {info} (Identity a) -> snonEmptyAggExpr info a)
5892 (pure exprs)
59−
60−
61−runAggregation :: Aggregates aggregates exprs => aggregates -> Aggregate exprs
62−runAggregation = fromColumns . toColumns
src/Rel8/Table/Alternative.hs+12−3
@@ -13,16 +13,25 @@ import Data.Kind ( Constraint, Type )
1313import Prelude ()
1414
1515-- rel8
16−import Rel8.Schema.Context ( DB )
16+import Rel8.Expr ( Expr )
1717import Rel8.Table ( Table )
1818
1919
20+-- | Like 'Alt' in Haskell. This class is purely a Rel8 concept, and allows you
21+-- to take a choice between two tables. See also 'AlternativeTable'.
22+--
23+-- For example, using '<|>:' on 'Rel8.MaybeTable' allows you to combine two
24+-- tables and to return the first one that is a "just" MaybeTable.
2025type AltTable :: (Type -> Type) -> Constraint
2126class AltTable f where
22− (<|>:) :: Table DB a => f a -> f a -> f a
27+ -- | An associative binary operation on 'Table's.
28+ (<|>:) :: Table Expr a => f a -> f a -> f a
2329 infixl 3 <|>:
2430
2531
32+-- | Like 'Alternative' in Haskell, some 'Table's form a monoid on applicative
33+-- functors.
2634type AlternativeTable :: (Type -> Type) -> Constraint
2735class AltTable f => AlternativeTable f where
28− emptyTable :: Table DB a => f a
36+ -- | The identity of '<|>:'.
37+ emptyTable :: Table Expr a => f a
src/Rel8/Table/Bool.hs+21−8
@@ -5,6 +5,7 @@
55module Rel8.Table.Bool
66 ( bool
77 , case_
8+ , nullable
89 )
910where
1011
@@ -14,22 +15,34 @@ import Prelude
1415-- rel8
1516import Rel8.Expr ( Expr )
1617import Rel8.Expr.Bool ( boolExpr, caseExpr )
17−import Rel8.Schema.Context ( DB( DB ), unDB )
18+import Rel8.Expr.Null ( isNull, unsafeUnnullify )
1819import Rel8.Schema.HTable ( htabulate, hfield )
1920import Rel8.Table ( Table, fromColumns, toColumns )
2021
2122
22−bool :: Table DB a => a -> a -> Expr Bool -> a
23+-- | An if-then-else expression on tables.
24+--
25+-- @bool x y p@ returns @x@ if @p@ is @False@, and returns @y@ if @p@ is
26+-- @True@.
27+bool :: Table Expr a => a -> a -> Expr Bool -> a
2328bool (toColumns -> false) (toColumns -> true) condition =
2429 fromColumns $ htabulate $ \field ->
2530 case (hfield false field, hfield true field) of
26− (DB falseExpr, DB trueExpr) ->
27− DB (boolExpr falseExpr trueExpr condition)
31+ (falseExpr, trueExpr) -> boolExpr falseExpr trueExpr condition
32+{-# INLINABLE bool #-}
2833
2934
30−case_ :: Table DB a => [(Expr Bool, a)] -> a -> a
35+-- | Produce a table expression from a list of alternatives. Returns the first
36+-- table where the @Expr Bool@ expression is @True@. If no alternatives are
37+-- true, the given default is returned.
38+case_ :: Table Expr a => [(Expr Bool, a)] -> a -> a
3139case_ (map (fmap toColumns) -> branches) (toColumns -> fallback) =
3240 fromColumns $ htabulate $ \field -> case hfield fallback field of
33− DB fallbackExpr ->
34− case map (fmap (unDB . (`hfield` field))) branches of
35− branchExprs -> DB (caseExpr branchExprs fallbackExpr)
41+ fallbackExpr ->
42+ case map (fmap (`hfield` field)) branches of
43+ branchExprs -> caseExpr branchExprs fallbackExpr
44+
45+
46+-- | Like 'maybe', but to eliminate @null@.
47+nullable :: Table Expr b => b -> (Expr a -> b) -> Expr (Maybe a) -> b
48+nullable b f ma = bool (f (unsafeUnnullify ma)) b (isNull ma)
src/Rel8/Table/Cols.hsnew file+50
@@ -0,0 +1,50 @@
1+{-# language DataKinds #-}
2+{-# language FlexibleInstances #-}
3+{-# language MultiParamTypeClasses #-}
4+{-# language StandaloneKindSignatures #-}
5+{-# language TypeFamilies #-}
6+{-# language UndecidableInstances #-}
7+
8+module Rel8.Table.Cols
9+ ( Cols( Cols )
10+ , fromCols
11+ , toCols
12+ )
13+where
14+
15+-- base
16+import Data.Kind ( Type )
17+import Prelude
18+
19+-- rel8
20+import qualified Rel8.Schema.Kind as K
21+import Rel8.Schema.HTable ( HTable )
22+import Rel8.Schema.Result ( Result )
23+import Rel8.Table ( Table(..) )
24+
25+
26+type Cols :: K.Context -> K.HTable -> Type
27+newtype Cols context columns = Cols (columns context)
28+
29+
30+instance (HTable columns, context ~ context') =>
31+ Table context' (Cols context columns)
32+ where
33+ type Columns (Cols context columns) = columns
34+ type Context (Cols context columns) = context
35+ type FromExprs (Cols context columns) = Cols Result columns
36+ type Transpose to (Cols context columns) = Cols to columns
37+
38+ toColumns (Cols a) = a
39+ fromColumns = Cols
40+
41+ toResult (Cols a) = a
42+ fromResult = Cols
43+
44+
45+fromCols :: Table context a => Cols context (Columns a) -> a
46+fromCols (Cols a) = fromColumns a
47+
48+
49+toCols :: Table context a => a -> Cols context (Columns a)
50+toCols = Cols . toColumns
src/Rel8/Table/Either.hs+161−92
@@ -3,46 +3,59 @@
33{-# language DerivingStrategies #-}
44{-# language FlexibleContexts #-}
55{-# language FlexibleInstances #-}
6+{-# language LambdaCase #-}
67{-# language MultiParamTypeClasses #-}
78{-# language NamedFieldPuns #-}
9+{-# language ScopedTypeVariables #-}
810{-# language StandaloneKindSignatures #-}
11+{-# language TypeApplications #-}
912{-# language TypeFamilies #-}
1013{-# language UndecidableInstances #-}
1114
15+{-# options_ghc -fno-warn-orphans #-}
16+
1217module Rel8.Table.Either
1318 ( EitherTable(..)
1419 , eitherTable, leftTable, rightTable
1520 , isLeftTable, isRightTable
21+ , aggregateEitherTable
22+ , nameEitherTable
1623 )
1724where
1825
1926-- base
2027import Data.Bifunctor ( Bifunctor, bimap )
21−import Data.Functor.Identity ( runIdentity )
28+import Data.Functor.Identity ( Identity( Identity ) )
2229import Data.Kind ( Type )
2330import Prelude hiding ( undefined )
2431
32+-- comonad
33+import Control.Comonad ( extract )
34+
2535-- rel8
36+import Rel8.Aggregate ( Aggregate )
2637import Rel8.Expr ( Expr )
38+import Rel8.Expr.Aggregate ( groupByExpr )
2739import Rel8.Expr.Serialize ( litExpr )
28−import Rel8.Schema.Context ( DB )
29−import Rel8.Schema.Context.Label ( Labelable, labeler, unlabeler )
30−import Rel8.Schema.Context.Nullify
31− ( Nullifiable, NullifiableEq
32− , encodeTag, decodeTag
33− , nullifier, unnullifier
34− )
40+import Rel8.Kind.Context ( Reifiable )
41+import Rel8.Schema.Context.Nullify ( Nullifiable )
42+import Rel8.Schema.Dict ( Dict( Dict ) )
3543import Rel8.Schema.HTable.Either ( HEitherTable(..) )
3644import Rel8.Schema.HTable.Identity ( HIdentity(..) )
37−import Rel8.Schema.HTable.Label ( HLabel, hlabel, hunlabel )
38−import Rel8.Schema.HTable.Nullify ( hnullify, hunnullify )
39−import Rel8.Table ( Table, Columns, Context, fromColumns, toColumns )
40−import Rel8.Table.Bool ( bool )
41−import Rel8.Table.Lifted
42− ( Table1, Columns1, ConstrainContext1, fromColumns1, toColumns1
43− , Table2, Columns2, ConstrainContext2, fromColumns2, toColumns2
45+import Rel8.Schema.HTable.Label ( hlabel, hunlabel )
46+import qualified Rel8.Schema.Kind as K
47+import Rel8.Schema.Name ( Name )
48+import Rel8.Table
49+ ( Table, Columns, Context, fromColumns, toColumns
50+ , FromExprs, fromResult, toResult
51+ , Transpose
4452 )
45−import Rel8.Table.Recontextualize ( Recontextualize )
53+import Rel8.Table.Bool ( bool )
54+import Rel8.Table.Eq ( EqTable, eqTable )
55+import Rel8.Table.Nullify ( Nullify, aggregateNullify, guard )
56+import Rel8.Table.Ord ( OrdTable, ordTable )
57+import Rel8.Table.Projection ( Biprojectable, Projectable, biproject, project )
58+import Rel8.Table.Serialize ( ToExprs )
4659import Rel8.Table.Undefined ( undefined )
4760import Rel8.Type.Tag ( EitherTag( IsLeft, IsRight ), isLeft, isRight )
4861
@@ -51,124 +64,180 @@ import Data.Functor.Apply ( Apply, (<.>) )
5164import Data.Functor.Bind ( Bind, (>>-) )
5265
5366
54−type EitherTable :: Type -> Type -> Type
55−data EitherTable a b = EitherTable
56− { tag :: Expr EitherTag
57− , left :: a
58− , right :: b
67+-- | An @EitherTable a b@ is a Rel8 table that contains either the table @a@ or
68+-- the table @b@. You can construct an @EitherTable@ using 'leftTable' and
69+-- 'rightTable', and eliminate/pattern match using 'eitherTable'.
70+--
71+-- An @EitherTable@ is operationally the same as Haskell's 'Either' type, but
72+-- adapted to work with Rel8.
73+type EitherTable :: K.Context -> Type -> Type -> Type
74+data EitherTable context a b = EitherTable
75+ { tag :: context EitherTag
76+ , left :: Nullify context a
77+ , right :: Nullify context b
5978 }
60− deriving stock (Show, Functor)
79+ deriving stock Functor
80+
81+
82+instance Biprojectable (EitherTable context) where
83+ biproject f g (EitherTable tag a b) =
84+ EitherTable tag (project f a) (project g b)
85+
6186
87+instance Nullifiable context => Bifunctor (EitherTable context) where
88+ bimap f g (EitherTable tag a b) = EitherTable tag (fmap f a) (fmap g b)
6289
63−instance Bifunctor EitherTable where
64− bimap f g (EitherTable tag a b) = EitherTable tag (f a) (g b)
6590
91+instance Projectable (EitherTable context a) where
92+ project f (EitherTable tag a b) = EitherTable tag a (project f b)
6693
67−instance Table DB a => Apply (EitherTable a) where
94+
95+instance (context ~ Expr, Table Expr a) => Apply (EitherTable context a) where
6896 EitherTable tag l1 f <.> EitherTable tag' l2 a =
69− EitherTable (tag <> tag') (bool l1 l2 (isLeft tag)) (f a)
97+ EitherTable (tag <> tag') (bool l1 l2 (isLeft tag)) (f <.> a)
7098
7199
72−instance Table DB a => Applicative (EitherTable a) where
100+instance (context ~ Expr, Table Expr a) => Applicative (EitherTable context a) where
73101 pure = rightTable
74102 (<*>) = (<.>)
75103
76104
77−instance Table DB a => Bind (EitherTable a) where
78− EitherTable tag l1 a >>- f = case f a of
105+instance (context ~ Expr, Table Expr a) => Bind (EitherTable context a) where
106+ EitherTable tag l1 a >>- f = case f (extract a) of
79107 EitherTable tag' l2 b ->
80108 EitherTable (tag <> tag') (bool l1 l2 (isRight tag)) b
81109
82110
83−instance Table DB a => Monad (EitherTable a) where
111+instance (context ~ Expr, Table Expr a) => Monad (EitherTable context a) where
84112 (>>=) = (>>-)
85113
86114
87−instance (Table DB a, Table DB b) => Semigroup (EitherTable a b) where
115+instance (context ~ Expr, Table Expr a, Table Expr b) =>
116+ Semigroup (EitherTable context a b)
117+ where
88118 a <> b = bool a b (isRightTable a)
89119
90120
91−instance Table2 EitherTable where
92− type Columns2 EitherTable = HEitherTable
93− type ConstrainContext2 EitherTable = Nullifiable
121+instance
122+ ( Table context a, Table context b
123+ , Reifiable context, context ~ context'
124+ )
125+ => Table context' (EitherTable context a b)
126+ where
127+ type Columns (EitherTable context a b) = HEitherTable (Columns a) (Columns b)
128+ type Context (EitherTable context a b) = Context a
129+ type FromExprs (EitherTable context a b) = Either (FromExprs a) (FromExprs b)
130+ type Transpose to (EitherTable context a b) =
131+ EitherTable to (Transpose to a) (Transpose to b)
132+
133+ toColumns EitherTable {tag, left, right} = HEitherTable
134+ { htag = hlabel $ HIdentity tag
135+ , hleft = hlabel $ guard tag (== IsLeft) isLeft $ toColumns left
136+ , hright = hlabel $ guard tag (== IsRight) isRight $ toColumns right
137+ }
94138
95− toColumns2 f g EitherTable {tag, left, right} = HEitherTable
96− { htag
97− , hleft = hnullify (nullifier (isLeft tag)) $ f left
98− , hright = hnullify (nullifier (isRight tag)) $ g right
139+ fromColumns HEitherTable {htag, hleft, hright} = EitherTable
140+ { tag = unHIdentity $ hunlabel htag
141+ , left = fromColumns $ hunlabel hleft
142+ , right = fromColumns $ hunlabel hright
99143 }
100− where
101− htag = HIdentity (encodeTag tag)
102−
103− fromColumns2 f g HEitherTable {htag = htag, hleft, hright} =
104− EitherTable
105− { tag
106− , left = f $ runIdentity $
107− hunnullify (\a -> pure . unnullifier (isLeft tag) a) hleft
108− , right = g $ runIdentity $
109− hunnullify (\a -> pure . unnullifier (isRight tag) a) hright
144+
145+ toResult = \case
146+ Left table -> HEitherTable
147+ { htag = hlabel (HIdentity (Identity IsLeft))
148+ , hleft = hlabel (toResult @_ @(Nullify context a) (Just table))
149+ , hright = hlabel (toResult @_ @(Nullify context b) Nothing)
150+ }
151+ Right table -> HEitherTable
152+ { htag = hlabel (HIdentity (Identity IsRight))
153+ , hleft = hlabel (toResult @_ @(Nullify context a) Nothing)
154+ , hright = hlabel (toResult @_ @(Nullify context b) (Just table))
110155 }
156+
157+ fromResult HEitherTable {htag, hleft, hright} = case hunlabel htag of
158+ HIdentity (Identity tag) -> case tag of
159+ IsLeft -> maybe err Left $ fromResult @_ @(Nullify context a) (hunlabel hleft)
160+ IsRight -> maybe err Right $ fromResult @_ @(Nullify context b) (hunlabel hright)
111161 where
112− tag = decodeTag $ unHIdentity htag
162+ err = error "Either.fromColumns: mismatch between tag and data"
113163
114− {-# INLINABLE fromColumns2 #-}
115− {-# INLINABLE toColumns2 #-}
116164
165+instance (EqTable a, EqTable b, context ~ Expr) =>
166+ EqTable (EitherTable context a b)
167+ where
168+ eqTable = HEitherTable
169+ { htag = hlabel (HIdentity Dict)
170+ , hleft = hlabel (eqTable @(Nullify context a))
171+ , hright = hlabel (eqTable @(Nullify context b))
172+ }
117173
118−instance Table context a => Table1 (EitherTable a) where
119− type Columns1 (EitherTable a) = HEitherTable (Columns a)
120− type ConstrainContext1 (EitherTable a) = NullifiableEq (Context a)
121174
122− toColumns1 = toColumns2 toColumns
123− fromColumns1 = fromColumns2 fromColumns
175+instance (OrdTable a, OrdTable b, context ~ Expr) =>
176+ OrdTable (EitherTable context a b)
177+ where
178+ ordTable = HEitherTable
179+ { htag = hlabel (HIdentity Dict)
180+ , hleft = hlabel (ordTable @(Nullify context a))
181+ , hright = hlabel (ordTable @(Nullify context b))
182+ }
124183
125184
126−instance
127− ( Table context a, Table context b
128− , Labelable context, Nullifiable context
129− ) =>
130− Table context (EitherTable a b)
131− where
132− type Columns (EitherTable a b) =
133− HEitherTable (HLabel "Left" (Columns a)) (HLabel "Right" (Columns b))
134− type Context (EitherTable a b) = Context a
185+instance (ToExprs exprs1 a, ToExprs exprs2 b, x ~ EitherTable Expr exprs1 exprs2) =>
186+ ToExprs x (Either a b)
135187
136− toColumns =
137− toColumns2
138− (hlabel labeler . toColumns)
139− (hlabel labeler . toColumns)
140− fromColumns =
141− fromColumns2
142− (fromColumns . hunlabel unlabeler)
143− (fromColumns . hunlabel unlabeler)
144188
189+-- | Test if an 'EitherTable' is a 'leftTable'.
190+isLeftTable :: EitherTable Expr a b -> Expr Bool
191+isLeftTable EitherTable {tag} = isLeft tag
145192
146−instance
147− ( Nullifiable from, Labelable from
148− , Nullifiable to, Labelable to
149− , Recontextualize from to a1 b1
150− , Recontextualize from to a2 b2
151− ) =>
152− Recontextualize from to (EitherTable a1 a2) (EitherTable b1 b2)
153193
194+-- | Test if an 'EitherTable' is a 'rightTable'.
195+isRightTable :: EitherTable Expr a b -> Expr Bool
196+isRightTable EitherTable {tag} = isRight tag
154197
155−isLeftTable :: EitherTable a b -> Expr Bool
156−isLeftTable = isLeft . tag
157198
199+-- | Pattern match/eliminate an 'EitherTable', by providing mappings from a
200+-- 'leftTable' and 'rightTable'.
201+eitherTable :: Table Expr c
202+ => (a -> c) -> (b -> c) -> EitherTable Expr a b -> c
203+eitherTable f g EitherTable {tag, left, right} =
204+ bool (f (extract left)) (g (extract right)) (isRight tag)
158205
159−isRightTable :: EitherTable a b -> Expr Bool
160−isRightTable = isRight . tag
161206
207+-- | Construct a left 'EitherTable'. Like 'Left'.
208+leftTable :: Table Expr b => a -> EitherTable Expr a b
209+leftTable a = EitherTable (litExpr IsLeft) (pure a) undefined
162210
163−eitherTable :: Table DB c
164− => (a -> c) -> (b -> c) -> EitherTable a b -> c
165−eitherTable f g EitherTable {tag, left, right} =
166− bool (f left) (g right) (isRight tag)
211+
212+-- | Construct a right 'EitherTable'. Like 'Right'.
213+rightTable :: Table Expr a => b -> EitherTable Expr a b
214+rightTable = EitherTable (litExpr IsRight) undefined . pure
167215
168216
169−leftTable :: Table DB b => a -> EitherTable a b
170−leftTable a = EitherTable (litExpr IsLeft) a undefined
217+-- | Lift a pair of aggregating functions to operate on an 'EitherTable'.
218+-- @leftTable@s and @rightTable@s are grouped separately.
219+aggregateEitherTable :: ()
220+ => (exprs -> aggregates)
221+ -> (exprs' -> aggregates')
222+ -> EitherTable Expr exprs exprs'
223+ -> EitherTable Aggregate aggregates aggregates'
224+aggregateEitherTable f g (EitherTable tag a b) = EitherTable
225+ { tag = groupByExpr tag
226+ , left = aggregateNullify f a
227+ , right = aggregateNullify g b
228+ }
171229
172230
173−rightTable :: Table DB a => b -> EitherTable a b
174−rightTable = EitherTable (litExpr IsRight) undefined
231+-- | Construct a 'EitherTable' in the 'Name' context. This can be useful if you
232+-- have a 'EitherTable' that you are storing in a table and need to construct a
233+-- 'TableSchema'.
234+nameEitherTable
235+ :: Name EitherTag
236+ -- ^ The name of the column to track whether a row is a 'leftTable' or
237+ -- 'rightTable'.
238+ -> a
239+ -- ^ Names of the columns in the @a@ table.
240+ -> b
241+ -- ^ Names of the columns in the @b@ table.
242+ -> EitherTable Name a b
243+nameEitherTable tag left right = EitherTable tag (pure left) (pure right)
src/Rel8/Table/Eq.hs+71−35
@@ -1,17 +1,20 @@
1+{-# language AllowAmbiguousTypes #-}
2+{-# language BlockArguments #-}
13{-# language DataKinds #-}
4+{-# language DefaultSignatures #-}
5+{-# language DisambiguateRecordFields #-}
26{-# language FlexibleContexts #-}
37{-# language FlexibleInstances #-}
4−{-# language NamedFieldPuns #-}
58{-# language ScopedTypeVariables #-}
69{-# language StandaloneKindSignatures #-}
710{-# language TypeApplications #-}
811{-# language TypeFamilies #-}
12+{-# language TypeOperators #-}
913{-# language UndecidableInstances #-}
10−{-# language UndecidableSuperClasses #-}
1114{-# language ViewPatterns #-}
1215
1316module Rel8.Table.Eq
14− ( EqTable, (==:), (/=:)
17+ ( EqTable( eqTable ), (==:), (/=:)
1518 )
1619where
1720
@@ -20,61 +23,94 @@ import Data.Foldable ( foldl' )
2023import Data.Functor.Const ( Const( Const ), getConst )
2124import Data.Kind ( Constraint, Type )
2225import Data.List.NonEmpty ( NonEmpty( (:|) ) )
23−import Prelude hiding ( seq )
26+import GHC.Generics ( Rep )
27+import Prelude
2428
2529-- rel8
2630import Rel8.Expr ( Expr )
2731import Rel8.Expr.Bool ( (||.), (&&.) )
28−import Rel8.Expr.Eq ( seq, sne )
29−import Rel8.Opaque ( Opaque )
30−import Rel8.Schema.Context ( DB( DB ) )
32+import Rel8.Expr.Eq ( (==.), (/=.) )
33+import Rel8.FCF ( Eval, Exp )
34+import Rel8.Generic.Record ( Record )
35+import Rel8.Generic.Table.Record ( GTable, GColumns, gtable )
3136import Rel8.Schema.Dict ( Dict( Dict ) )
32−import Rel8.Schema.HTable
33− ( HConstrainTable
34− , htabulateA, hfield
35− , hdicts, hspecs
36− )
37−import Rel8.Schema.Spec ( SSpec(..) )
38−import Rel8.Schema.Spec.ConstrainDBType ( ConstrainDBType )
39−import Rel8.Table ( Table, Columns, toColumns )
37+import Rel8.Schema.HTable ( htabulateA, hfield )
38+import Rel8.Schema.HTable.Identity ( HIdentity( HIdentity ) )
39+import Rel8.Schema.Null ( Sql )
40+import Rel8.Table ( Table, Columns, toColumns, TColumns )
4041import Rel8.Type.Eq ( DBEq )
4142
4243
44+-- | The class of 'Table's that can be compared for equality. Equality on
45+-- tables is defined by equality of all columns all columns, so this class
46+-- means "all columns in a 'Table' have an instance of 'DBEq'".
4347type EqTable :: Type -> Constraint
44−class
45− ( Table DB a
46− , HConstrainTable (Columns a) (ConstrainDBType DBEq)
47− ) => EqTable a
48+class Table Expr a => EqTable a where
49+ eqTable :: Columns a (Dict (Sql DBEq))
50+
51+ default eqTable ::
52+ ( GTable TEqTable TColumns (Rep (Record a))
53+ , Columns a ~ GColumns TColumns (Rep (Record a))
54+ )
55+ => Columns a (Dict (Sql DBEq))
56+ eqTable = gtable @TEqTable @TColumns @(Rep (Record a)) table
57+ where
58+ table (_ :: proxy x) = eqTable @x
59+
60+
61+data TEqTable :: Type -> Exp Constraint
62+type instance Eval (TEqTable a) = EqTable a
63+
64+
65+instance Sql DBEq a => EqTable (Expr a) where
66+ eqTable = HIdentity Dict
67+
68+
69+instance (EqTable a, EqTable b) => EqTable (a, b)
70+
71+
72+instance (EqTable a, EqTable b, EqTable c) => EqTable (a, b, c)
73+
74+
75+instance (EqTable a, EqTable b, EqTable c, EqTable d) => EqTable (a, b, c, d)
76+
77+
78+instance (EqTable a, EqTable b, EqTable c, EqTable d, EqTable e) =>
79+ EqTable (a, b, c, d, e)
80+
81+
82+instance (EqTable a, EqTable b, EqTable c, EqTable d, EqTable e, EqTable f) =>
83+ EqTable (a, b, c, d, e, f)
84+
85+
4886instance
49− ( Table DB a
50− , HConstrainTable (Columns a) (ConstrainDBType DBEq)
51− ) => EqTable a
52−instance {-# OVERLAPPING #-} EqTable Opaque
87+ ( EqTable a, EqTable b, EqTable c, EqTable d, EqTable e, EqTable f
88+ , EqTable g
89+ )
90+ => EqTable (a, b, c, d, e, f, g)
5391
5492
93+-- | Compare two 'Table's for equality. This corresponds to comparing all
94+-- columns inside each table for equality, and combining all comparisons with
95+-- @AND@.
5596(==:) :: forall a. EqTable a => a -> a -> Expr Bool
5697(toColumns -> as) ==: (toColumns -> bs) =
5798 foldl1' (&&.) $ getConst $ htabulateA $ \field ->
5899 case (hfield as field, hfield bs field) of
59− (DB a, DB b) -> case hfield dicts field of
60− Dict -> case hfield specs field of
61− SSpec {nullability} -> Const (pure (seq nullability a b))
62− where
63− dicts = hdicts @(Columns a) @(ConstrainDBType DBEq)
64− specs = hspecs @(Columns a)
100+ (a, b) -> case hfield (eqTable @a) field of
101+ Dict -> Const (pure (a ==. b))
65102infix 4 ==:
66103
67104
105+-- | Test if two 'Table's are different. This corresponds to comparing all
106+-- columns inside each table for inequality, and combining all comparisons with
107+-- @OR@.
68108(/=:) :: forall a. EqTable a => a -> a -> Expr Bool
69109(toColumns -> as) /=: (toColumns -> bs) =
70110 foldl1' (||.) $ getConst $ htabulateA $ \field ->
71111 case (hfield as field, hfield bs field) of
72− (DB a, DB b) -> case hfield dicts field of
73− Dict -> case hfield specs field of
74− SSpec {nullability} -> Const (pure (sne nullability a b))
75− where
76− dicts = hdicts @(Columns a) @(ConstrainDBType DBEq)
77− specs = hspecs @(Columns a)
112+ (a, b) -> case hfield (eqTable @a) field of
113+ Dict -> Const (pure (a /=. b))
78114infix 4 /=:
79115
80116
src/Rel8/Table/HKD.hsnew file+228
@@ -0,0 +1,228 @@
1+{-# language AllowAmbiguousTypes #-}
2+{-# language DataKinds #-}
3+{-# language FlexibleContexts #-}
4+{-# language FlexibleInstances #-}
5+{-# language MultiParamTypeClasses #-}
6+{-# language RankNTypes #-}
7+{-# language ScopedTypeVariables #-}
8+{-# language StandaloneKindSignatures #-}
9+{-# language TypeApplications #-}
10+{-# language TypeFamilies #-}
11+{-# language UndecidableInstances #-}
12+{-# language UndecidableSuperClasses #-}
13+
14+module Rel8.Table.HKD
15+ ( HKD( HKD )
16+ , HKDable
17+ , BuildableHKD
18+ , BuildHKD, buildHKD
19+ , ConstructableHKD
20+ , ConstructHKD, constructHKD
21+ , DeconstructHKD, deconstructHKD
22+ , NameHKD, nameHKD
23+ , AggregateHKD, aggregateHKD
24+ , HKDRep
25+ )
26+where
27+
28+-- base
29+import Data.Kind ( Constraint, Type )
30+import GHC.Generics ( Generic, Rep, from, to )
31+import GHC.TypeLits ( Symbol )
32+import Prelude
33+
34+-- rel8
35+import Rel8.Aggregate ( Aggregate )
36+import Rel8.Column ( TColumn )
37+import Rel8.Expr ( Expr )
38+import Rel8.FCF ( Eval, Exp )
39+import Rel8.Kind.Algebra ( KnownAlgebra )
40+import Rel8.Generic.Construction
41+ ( GGBuildable
42+ , GGBuild, ggbuild
43+ , GGConstructable
44+ , GGConstruct, ggconstruct
45+ , GGDeconstruct, ggdeconstruct
46+ , GGName, ggname
47+ , GGAggregate, ggaggregate
48+ )
49+import Rel8.Generic.Map ( GMap )
50+import Rel8.Generic.Record
51+ ( GRecord, GRecordable, grecord, gunrecord
52+ , Record( Record ), unrecord
53+ )
54+import Rel8.Generic.Rel8able
55+ ( Rel8able
56+ , GColumns, gfromColumns, gtoColumns
57+ , GFromExprs, gfromResult, gtoResult
58+ )
59+import Rel8.Generic.Table
60+ ( GGSerialize, GGColumns, GAlgebra, ggfromResult, ggtoResult
61+ )
62+import Rel8.Generic.Table.Record ( GTable, GContext )
63+import qualified Rel8.Generic.Table.Record as G
64+import qualified Rel8.Schema.Kind as K
65+import Rel8.Schema.HTable ( HTable )
66+import Rel8.Schema.Name ( Name )
67+import Rel8.Schema.Result ( Result )
68+import Rel8.Table
69+ ( Table, fromColumns, toColumns, fromResult, toResult
70+ , TTable, TColumns, TContext
71+ , TSerialize
72+ )
73+
74+
75+type GColumnsHKD :: Type -> K.HTable
76+type GColumnsHKD a =
77+ Eval (GGColumns (GAlgebra (Rep a)) TColumns (GRecord (GMap (TColumn Expr) (Rep a))))
78+
79+
80+type HKD :: Type -> K.Rel8able
81+newtype HKD a f = HKD (GColumnsHKD a f)
82+
83+
84+instance HKDable a => Rel8able (HKD a) where
85+ type GColumns (HKD a) = GColumnsHKD a
86+ type GFromExprs (HKD a) = a
87+
88+ gfromColumns _ = HKD
89+ gtoColumns _ (HKD a) = a
90+
91+ gfromResult =
92+ unrecord .
93+ to .
94+ ggfromResult
95+ @(GAlgebra (Rep a))
96+ @TSerialize
97+ @TColumns
98+ @(Eval (HKDRep a Expr))
99+ @(Eval (HKDRep a Result))
100+ (\(_ :: proxy x) -> fromResult @_ @x)
101+
102+ gtoResult =
103+ ggtoResult
104+ @(GAlgebra (Rep a))
105+ @TSerialize
106+ @TColumns
107+ @(Eval (HKDRep a Expr))
108+ @(Eval (HKDRep a Result))
109+ (\(_ :: proxy x) -> toResult @_ @x) .
110+ from .
111+ Record
112+
113+
114+instance
115+ ( GTable (TTable f) TColumns (GRecord (GMap (TColumn f) (Rep a)))
116+ , G.GColumns TColumns (GRecord (GMap (TColumn f) (Rep a))) ~ GColumnsHKD a
117+ , GContext TContext (GRecord (GMap (TColumn f) (Rep a))) ~ f
118+ , GRecordable (GMap (TColumn f) (Rep a))
119+ )
120+ => Generic (HKD a f)
121+ where
122+ type Rep (HKD a f) = GMap (TColumn f) (Rep a)
123+
124+ from =
125+ gunrecord @(GMap (TColumn f) (Rep a)) .
126+ G.gfromColumns
127+ @(TTable f)
128+ @TColumns
129+ fromColumns .
130+ (\(HKD a) -> a)
131+
132+ to =
133+ HKD .
134+ G.gtoColumns
135+ @(TTable f)
136+ @TColumns
137+ toColumns .
138+ grecord @(GMap (TColumn f) (Rep a))
139+
140+
141+type HKDable :: Type -> Constraint
142+class
143+ ( Generic (Record a)
144+ , HTable (GColumns (HKD a))
145+ , KnownAlgebra (GAlgebra (Rep a))
146+ , Eval (GGSerialize (GAlgebra (Rep a)) TSerialize TColumns (Eval (HKDRep a Expr)) (Eval (HKDRep a Result)))
147+ , GRecord (GMap (TColumn Result) (Rep a)) ~ Rep (Record a)
148+ )
149+ => HKDable a
150+instance
151+ ( Generic (Record a)
152+ , HTable (GColumns (HKD a))
153+ , KnownAlgebra (GAlgebra (Rep a))
154+ , Eval (GGSerialize (GAlgebra (Rep a)) TSerialize TColumns (Eval (HKDRep a Expr)) (Eval (HKDRep a Result)))
155+ , GRecord (GMap (TColumn Result) (Rep a)) ~ Rep (Record a)
156+ )
157+ => HKDable a
158+
159+
160+type Top_ :: Constraint
161+class Top_
162+instance Top_
163+
164+
165+data Top :: Type -> Exp Constraint
166+type instance Eval (Top _) = Top_
167+
168+
169+type BuildableHKD :: Type -> Symbol -> Constraint
170+class GGBuildable (GAlgebra (Rep a)) name (HKDRep a) => BuildableHKD a name
171+instance GGBuildable (GAlgebra (Rep a)) name (HKDRep a) => BuildableHKD a name
172+
173+
174+type BuildHKD :: Type -> Symbol -> Type
175+type BuildHKD a name = GGBuild (GAlgebra (Rep a)) name (HKDRep a) (HKD a Expr)
176+
177+
178+buildHKD :: forall a name. BuildableHKD a name => BuildHKD a name
179+buildHKD =
180+ ggbuild @(GAlgebra (Rep a)) @name @(HKDRep a) @(HKD a Expr) HKD
181+
182+
183+type ConstructableHKD :: Type -> Constraint
184+class GGConstructable (GAlgebra (Rep a)) (HKDRep a) => ConstructableHKD a
185+instance GGConstructable (GAlgebra (Rep a)) (HKDRep a) => ConstructableHKD a
186+
187+
188+type ConstructHKD :: Type -> Type
189+type ConstructHKD a = forall r. GGConstruct (GAlgebra (Rep a)) (HKDRep a) r
190+
191+
192+constructHKD :: forall a. ConstructableHKD a => ConstructHKD a -> HKD a Expr
193+constructHKD f =
194+ ggconstruct @(GAlgebra (Rep a)) @(HKDRep a) @(HKD a Expr) HKD
195+ (f @(HKD a Expr))
196+
197+
198+type DeconstructHKD :: Type -> Type -> Type
199+type DeconstructHKD a r = GGDeconstruct (GAlgebra (Rep a)) (HKDRep a) (HKD a Expr) r
200+
201+
202+deconstructHKD :: forall a r. (ConstructableHKD a, Table Expr r)
203+ => DeconstructHKD a r
204+deconstructHKD = ggdeconstruct @(GAlgebra (Rep a)) @(HKDRep a) @(HKD a Expr) @r (\(HKD a) -> a)
205+
206+
207+type NameHKD :: Type -> Type
208+type NameHKD a = GGName (GAlgebra (Rep a)) (HKDRep a) (HKD a Name)
209+
210+
211+nameHKD :: forall a. ConstructableHKD a => NameHKD a
212+nameHKD = ggname @(GAlgebra (Rep a)) @(HKDRep a) @(HKD a Name) HKD
213+
214+
215+type AggregateHKD :: Type -> Type
216+type AggregateHKD a = forall r. GGAggregate (GAlgebra (Rep a)) (HKDRep a) r
217+
218+
219+aggregateHKD :: forall a. ConstructableHKD a
220+ => AggregateHKD a -> HKD a Expr -> HKD a Aggregate
221+aggregateHKD f =
222+ ggaggregate @(GAlgebra (Rep a)) @(HKDRep a) @(HKD a Expr) @(HKD a Aggregate) HKD (\(HKD a) -> a)
223+ (f @(HKD a Aggregate))
224+
225+
226+data HKDRep :: Type -> K.Context -> Exp (Type -> Type)
227+type instance Eval (HKDRep a context) =
228+ GRecord (GMap (TColumn context) (Rep a))
src/Rel8/Table/Insert.hsdeleted−39
@@ -1,39 +0,0 @@
1−{-# language FlexibleContexts #-}
2−{-# language NamedFieldPuns #-}
3−{-# language TypeFamilies #-}
4−{-# language ViewPatterns #-}
5−
6−module Rel8.Table.Insert
7− ( toInsert
8− , toInsertDefaults
9− )
10−where
11−
12−-- base
13−import Prelude
14−
15−-- rel8
16−import Rel8.Kind.Necessity ( SNecessity( SOptional, SRequired ) )
17−import Rel8.Schema.Context ( DB(..), Insertion(..) )
18−import Rel8.Schema.HTable ( hfield, htabulate, hspecs )
19−import Rel8.Schema.Spec ( SSpec(..) )
20−import Rel8.Table ( fromColumns, toColumns )
21−import Rel8.Table.Recontextualize ( Inserts )
22−
23−
24−toInsert :: Inserts exprs inserts => exprs -> inserts
25−toInsert (toColumns -> exprs) = fromColumns $ htabulate $ \field ->
26− case hfield hspecs field of
27− SSpec {necessity} -> case hfield exprs field of
28− DB expr -> case necessity of
29− SRequired -> RequiredInsert expr
30− SOptional -> OptionalInsert (Just expr)
31−
32−
33−toInsertDefaults :: Inserts exprs inserts => exprs -> inserts
34−toInsertDefaults (toColumns -> exprs) = fromColumns $ htabulate $ \field ->
35− case hfield hspecs field of
36− SSpec {necessity} -> case hfield exprs field of
37− DB expr -> case necessity of
38− SRequired -> RequiredInsert expr
39− SOptional -> OptionalInsert Nothing
src/Rel8/Table/Lifted.hsdeleted−62
@@ -1,62 +0,0 @@
1−{-# language ConstrainedClassMethods #-}
2−{-# language DataKinds #-}
3−{-# language FlexibleContexts #-}
4−{-# language FlexibleInstances #-}
5−{-# language StandaloneKindSignatures #-}
6−{-# language TypeFamilies #-}
7−
8−module Rel8.Table.Lifted
9− ( Table1( Columns1, ConstrainContext1, toColumns1, fromColumns1 )
10− , Table2( Columns2, ConstrainContext2, toColumns2, fromColumns2 )
11− )
12−where
13−
14−-- base
15−import Data.Kind ( Constraint, Type )
16−import Prelude ()
17−
18−-- rel8
19−import Rel8.Schema.HTable ( HTable )
20−import Rel8.Schema.HTable.Context ( H, HKTable )
21−import Rel8.Schema.Spec ( Context )
22−
23−
24−type Table1 :: (Type -> Type) -> Constraint
25−class Table1 f where
26− type Columns1 f :: HKTable -> HKTable
27− type ConstrainContext1 f :: Context -> Constraint
28− type ConstrainContext1 _ = DefaultConstrainContext
29−
30− toColumns1 :: (ConstrainContext1 f context, HTable t)
31− => (a -> t (H context))
32− -> f a
33− -> Columns1 f t (H context)
34−
35− fromColumns1 :: (ConstrainContext1 f context, HTable t)
36− => (t (H context) -> a)
37− -> Columns1 f t (H context)
38− -> f a
39−
40−
41−type Table2 :: (Type -> Type -> Type) -> Constraint
42−class Table2 p where
43− type Columns2 p :: HKTable -> HKTable -> HKTable
44− type ConstrainContext2 p :: Context -> Constraint
45− type ConstrainContext2 _ = DefaultConstrainContext
46−
47− toColumns2 :: (ConstrainContext2 p context, HTable t, HTable u)
48− => (a -> t (H context))
49− -> (b -> u (H context))
50− -> p a b
51− -> Columns2 p t u (H context)
52−
53− fromColumns2 :: (ConstrainContext2 p context, HTable t, HTable u)
54− => (t (H context) -> a)
55− -> (u (H context) -> b)
56− -> Columns2 p t u (H context)
57− -> p a b
58−
59−
60−type DefaultConstrainContext :: Context -> Constraint
61−class DefaultConstrainContext context
62−instance DefaultConstrainContext context
src/Rel8/Table/List.hs+108−21
@@ -1,62 +1,149 @@
1+{-# language DataKinds #-}
12{-# language FlexibleContexts #-}
23{-# language FlexibleInstances #-}
34{-# language MultiParamTypeClasses #-}
5+{-# language NamedFieldPuns #-}
6+{-# language ScopedTypeVariables #-}
47{-# language StandaloneKindSignatures #-}
8+{-# language TypeApplications #-}
59{-# language TypeFamilies #-}
610{-# language UndecidableInstances #-}
711
812module Rel8.Table.List
913 ( ListTable(..)
14+ , ($*)
15+ , listTable
16+ , nameListTable
1017 )
1118where
1219
1320-- base
21+import Data.Functor.Identity ( Identity( Identity ) )
1422import Data.Kind ( Type )
1523import Prelude
1624
1725-- rel8
18−import Rel8.Expr.Array ( sappend, sempty )
19−import Rel8.Schema.Context ( DB( DB ) )
20−import Rel8.Schema.HTable.Context ( H )
26+import Rel8.Expr ( Expr )
27+import Rel8.Expr.Array ( sappend, sempty, slistOf )
28+import Rel8.Schema.Dict ( Dict( Dict ) )
2129import Rel8.Schema.HTable.List ( HListTable )
22−import Rel8.Schema.HTable.Vectorize ( happend, hempty )
23−import Rel8.Table ( Table, Context, Columns, fromColumns, toColumns )
30+import Rel8.Schema.HTable.Vectorize
31+ ( hvectorize, hunvectorize
32+ , happend, hempty
33+ , hproject, hcolumn
34+ )
35+import qualified Rel8.Schema.Kind as K
36+import Rel8.Schema.Name ( Name( Name ) )
37+import Rel8.Schema.Null ( Nullity( Null, NotNull ) )
38+import Rel8.Schema.Result ( vectorizer, unvectorizer )
39+import Rel8.Schema.Spec ( Spec(..) )
40+import Rel8.Table
41+ ( Table, Context, Columns, fromColumns, toColumns
42+ , FromExprs, fromResult, toResult
43+ , Transpose
44+ )
2445import Rel8.Table.Alternative
2546 ( AltTable, (<|>:)
2647 , AlternativeTable, emptyTable
2748 )
28−import Rel8.Table.Recontextualize ( Recontextualize )
49+import Rel8.Table.Eq ( EqTable, eqTable )
50+import Rel8.Table.Ord ( OrdTable, ordTable )
51+import Rel8.Table.Projection
52+ ( Projectable, Projecting, Projection, project, apply
53+ )
54+import Rel8.Table.Serialize ( ToExprs )
55+
2956
57+-- | A @ListTable@ value contains zero or more instances of @a@. You construct
58+-- @ListTable@s with 'Rel8.many' or 'Rel8.listAgg'.
59+type ListTable :: K.Context -> Type -> Type
60+newtype ListTable context a =
61+ ListTable (HListTable (Columns a) (Context a))
3062
31−type ListTable :: Type -> Type
32−newtype ListTable a = ListTable (HListTable (Columns a) (H (Context a)))
3363
64+instance Projectable (ListTable context) where
65+ project f (ListTable a) = ListTable (hproject (apply f) a)
3466
35−instance Table context a => Table context (ListTable a) where
36− type Columns (ListTable a) = HListTable (Columns a)
37− type Context (ListTable a) = Context a
67+
68+instance (Table context a, context ~ context') =>
69+ Table context' (ListTable context a)
70+ where
71+ type Columns (ListTable context a) = HListTable (Columns a)
72+ type Context (ListTable context a) = Context a
73+ type FromExprs (ListTable context a) = [FromExprs a]
74+ type Transpose to (ListTable context a) = ListTable to (Transpose to a)
3875
3976 fromColumns = ListTable
4077 toColumns (ListTable a) = a
78+ fromResult = fmap (fromResult @_ @a) . hunvectorize unvectorizer
79+ toResult = hvectorize vectorizer . fmap (toResult @_ @a)
80+
81+
82+instance (EqTable a, context ~ Expr) => EqTable (ListTable context a) where
83+ eqTable =
84+ hvectorize
85+ (\Spec {nullity} (Identity Dict) -> case nullity of
86+ Null -> Dict
87+ NotNull -> Dict)
88+ (Identity (eqTable @a))
89+
4190
91+instance (OrdTable a, context ~ Expr) => OrdTable (ListTable context a) where
92+ ordTable =
93+ hvectorize
94+ (\Spec {nullity} (Identity Dict) -> case nullity of
95+ Null -> Dict
96+ NotNull -> Dict)
97+ (Identity (ordTable @a))
4298
43−instance Recontextualize from to a b =>
44− Recontextualize from to (ListTable a) (ListTable b)
4599
100+instance (ToExprs exprs a, context ~ Expr) =>
101+ ToExprs (ListTable context exprs) [a]
46102
47−instance AltTable ListTable where
103+
104+instance context ~ Expr => AltTable (ListTable context) where
48105 (<|>:) = (<>)
49106
50107
51−instance AlternativeTable ListTable where
108+instance context ~ Expr => AlternativeTable (ListTable context) where
52109 emptyTable = mempty
53110
54111
55−instance Table DB a => Semigroup (ListTable a) where
56− ListTable as <> ListTable bs = ListTable $
57− happend (\_ _ (DB a) (DB b) -> DB (sappend a b)) as bs
112+instance (context ~ Expr, Table Expr a) => Semigroup (ListTable context a)
113+ where
114+ ListTable as <> ListTable bs = ListTable $ happend (const sappend) as bs
115+
116+
117+instance (context ~ Expr, Table Expr a) =>
118+ Monoid (ListTable context a)
119+ where
120+ mempty = ListTable $ hempty $ \Spec {info} -> sempty info
121+
122+
123+-- | Project a single expression out of a 'ListTable'.
124+($*) :: Projecting a (Expr b)
125+ => Projection a (Expr b) -> ListTable Expr a -> Expr [b]
126+f $* ListTable a = hcolumn $ hproject (apply f) a
127+infixl 4 $*
128+
129+
130+-- | Construct a @ListTable@ from a list of expressions.
131+listTable :: Table Expr a => [a] -> ListTable Expr a
132+listTable =
133+ ListTable .
134+ hvectorize (\Spec {info} -> slistOf info) .
135+ fmap toColumns
58136
59137
60−instance Table DB a => Monoid (ListTable a) where
61− mempty = ListTable $ hempty $ \nullability info ->
62− DB (sempty nullability info)
138+-- | Construct a 'ListTable' in the 'Name' context. This can be useful if you
139+-- have a 'ListTable' that you are storing in a table and need to construct a
140+-- 'TableSchema'.
141+nameListTable
142+ :: Table Name a
143+ => a -- ^ The names of the columns of elements of the list.
144+ -> ListTable Name a
145+nameListTable =
146+ ListTable .
147+ hvectorize (\_ (Identity (Name a)) -> Name a) .
148+ pure .
149+ toColumns
src/Rel8/Table/Maybe.hs+149−83
@@ -15,45 +15,53 @@ module Rel8.Table.Maybe
1515 ( MaybeTable(..)
1616 , maybeTable, nothingTable, justTable
1717 , isNothingTable, isJustTable
18+ , fromMaybeTable
1819 , ($?)
20+ , aggregateMaybeTable
21+ , nameMaybeTable
1922 )
2023where
2124
2225-- base
23−import Data.Functor.Identity ( runIdentity )
26+import Data.Functor ( ($>) )
27+import Data.Functor.Identity ( Identity( Identity ) )
2428import Data.Kind ( Type )
25−import Prelude hiding ( null, repeat, undefined, zipWith )
29+import Data.Maybe ( fromMaybe, isJust )
30+import Prelude hiding ( null, undefined )
31+
32+-- comonad
33+import Control.Comonad ( extract )
2634
2735-- rel8
36+import Rel8.Aggregate ( Aggregate )
2837import Rel8.Expr ( Expr )
38+import Rel8.Expr.Aggregate ( groupByExpr )
2939import Rel8.Expr.Bool ( boolExpr )
3040import Rel8.Expr.Null ( isNull, isNonNull, null, nullify )
31−import Rel8.Expr.Serialize ( litExpr )
32−import Rel8.Schema.Context ( DB )
33−import Rel8.Schema.Context.Label ( Labelable, labeler, unlabeler )
34−import Rel8.Schema.Context.Nullify
35− ( Nullifiable
36− , encodeTag, decodeTag
37− , nullifier, unnullifier
38− )
41+import Rel8.Kind.Context ( Reifiable )
42+import Rel8.Schema.Dict ( Dict( Dict ) )
43+import qualified Rel8.Schema.Kind as K
3944import Rel8.Schema.HTable.Identity ( HIdentity(..) )
40−import Rel8.Schema.HTable.Label ( HLabel, hlabel, hunlabel )
45+import Rel8.Schema.HTable.Label ( hlabel, hunlabel )
4146import Rel8.Schema.HTable.Maybe ( HMaybeTable(..) )
42−import Rel8.Schema.HTable.Nullify ( hnullify, hunnullify )
43−import Rel8.Schema.Nullability
44− ( Nullability( Nullable, NonNullable )
45− , Nullabilizes, nullabilization
47+import Rel8.Schema.Name ( Name )
48+import Rel8.Schema.Null ( Nullity( Null, NotNull ), Sql, nullable )
49+import qualified Rel8.Schema.Null as N
50+import Rel8.Table
51+ ( Table, Columns, Context, fromColumns, toColumns
52+ , FromExprs, fromResult, toResult
53+ , Transpose
4654 )
47−import Rel8.Table ( Table, Columns, Context, fromColumns, toColumns )
4855import Rel8.Table.Alternative
4956 ( AltTable, (<|>:)
5057 , AlternativeTable, emptyTable
5158 )
5259import Rel8.Table.Bool ( bool )
53−import Rel8.Table.Lifted
54− ( Table1, Columns1, ConstrainContext1, fromColumns1, toColumns1
55− )
56−import Rel8.Table.Recontextualize ( Recontextualize )
60+import Rel8.Table.Eq ( EqTable, eqTable )
61+import Rel8.Table.Ord ( OrdTable, ordTable )
62+import Rel8.Table.Projection ( Projectable, project )
63+import Rel8.Table.Nullify ( Nullify, aggregateNullify, guard )
64+import Rel8.Table.Serialize ( ToExprs )
5765import Rel8.Table.Undefined ( undefined )
5866import Rel8.Type ( DBType )
5967import Rel8.Type.Tag ( MaybeTag( IsJust ) )
@@ -63,118 +71,176 @@ import Data.Functor.Apply ( Apply, (<.>) )
6371import Data.Functor.Bind ( Bind, (>>-) )
6472
6573
66−type MaybeTable :: Type -> Type
67−data MaybeTable a = MaybeTable
68− { tag :: Expr (Maybe MaybeTag)
69− , just :: a
74+-- | @MaybeTable t@ is the table @t@, but as the result of an outer join. If
75+-- the outer join fails to match any rows, this is essentialy @Nothing@, and if
76+-- the outer join does match rows, this is like @Just@. Unfortunately, SQL
77+-- makes it impossible to distinguish whether or not an outer join matched any
78+-- rows based generally on the row contents - if you were to join a row
79+-- entirely of nulls, you can't distinguish if you matched an all null row, or
80+-- if the match failed. For this reason @MaybeTable@ contains an extra field -
81+-- a "nullTag" - to track whether or not the outer join produced any rows.
82+type MaybeTable :: K.Context -> Type -> Type
83+data MaybeTable context a = MaybeTable
84+ { tag :: context (Maybe MaybeTag)
85+ , just :: Nullify context a
7086 }
71− deriving stock (Show, Functor)
87+ deriving stock Functor
88+
89+
90+instance Projectable (MaybeTable context) where
91+ project f (MaybeTable tag a) = MaybeTable tag (project f a)
7292
7393
74−instance Apply MaybeTable where
75− MaybeTable tag f <.> MaybeTable tag' a = MaybeTable (tag <> tag') (f a)
94+instance context ~ Expr => Apply (MaybeTable context) where
95+ MaybeTable tag f <.> MaybeTable tag' a = MaybeTable (tag <> tag') (f <.> a)
7696
7797
78−instance Applicative MaybeTable where
98+-- | Has the same behavior as the @Applicative@ instance for @Maybe@. See also:
99+-- 'Rel8.traverseMaybeTable'.
100+instance context ~ Expr => Applicative (MaybeTable context) where
79101 (<*>) = (<.>)
80102 pure = justTable
81103
82104
83−instance Bind MaybeTable where
84− MaybeTable tag a >>- f = case f a of
105+instance context ~ Expr => Bind (MaybeTable context) where
106+ MaybeTable tag a >>- f = case f (extract a) of
85107 MaybeTable tag' b -> MaybeTable (tag <> tag') b
86108
87109
88−instance Monad MaybeTable where
110+-- | Has the same behavior as the @Monad@ instance for @Maybe@.
111+instance context ~ Expr => Monad (MaybeTable context) where
89112 (>>=) = (>>-)
90113
91114
92−instance AltTable MaybeTable where
93− ma@(MaybeTable tag a) <|>: MaybeTable tag' b = MaybeTable
94− { tag = boolExpr tag tag' condition
95− , just = bool a b condition
96− }
97− where
98− condition = isNothingTable ma
115+instance context ~ Expr => AltTable (MaybeTable context) where
116+ ma <|>: mb = bool ma mb (isNothingTable ma)
99117
100118
101−instance AlternativeTable MaybeTable where
119+instance context ~ Expr => AlternativeTable (MaybeTable context) where
102120 emptyTable = nothingTable
103121
104122
105−instance (Table DB a, Semigroup a) => Semigroup (MaybeTable a) where
123+instance (context ~ Expr, Table Expr a, Semigroup a) =>
124+ Semigroup (MaybeTable context a)
125+ where
106126 ma <> mb = maybeTable mb (\a -> maybeTable ma (justTable . (a <>)) mb) ma
107127
108128
109−instance (Table DB a, Semigroup a) => Monoid (MaybeTable a) where
129+instance (context ~ Expr, Table Expr a, Semigroup a) =>
130+ Monoid (MaybeTable context a)
131+ where
110132 mempty = nothingTable
111133
112134
113−instance Table1 MaybeTable where
114− type Columns1 MaybeTable = HMaybeTable
115− type ConstrainContext1 MaybeTable = Nullifiable
135+instance (Table context a, Reifiable context, context ~ context') =>
136+ Table context' (MaybeTable context a)
137+ where
138+ type Columns (MaybeTable context a) = HMaybeTable (Columns a)
139+ type Context (MaybeTable context a) = Context a
140+ type FromExprs (MaybeTable context a) = Maybe (FromExprs a)
141+ type Transpose to (MaybeTable context a) = MaybeTable to (Transpose to a)
142+
143+ toColumns MaybeTable {tag, just} = HMaybeTable
144+ { htag = hlabel $ HIdentity tag
145+ , hjust = hlabel $ guard tag isJust isNonNull $ toColumns just
146+ }
116147
117− toColumns1 f MaybeTable {tag, just} = HMaybeTable
118− { htag
119− , hjust = hnullify (nullifier (isNonNull tag)) $ f just
148+ fromColumns HMaybeTable {htag, hjust} = MaybeTable
149+ { tag = unHIdentity $ hunlabel htag
150+ , just = fromColumns $ hunlabel hjust
120151 }
121− where
122− htag = HIdentity (encodeTag tag)
123152
124− fromColumns1 f HMaybeTable {htag = HIdentity htag, hjust} = MaybeTable
125− { tag
126− , just = f $ runIdentity $
127− hunnullify (\a -> pure . unnullifier (isNonNull tag) a) hjust
153+ toResult ma = HMaybeTable
154+ { htag = hlabel (HIdentity (Identity (IsJust <$ ma)))
155+ , hjust = hlabel (toResult @_ @(Nullify context a) ma)
128156 }
157+
158+ fromResult HMaybeTable {htag, hjust} = case hunlabel htag of
159+ HIdentity (Identity tag) -> tag $>
160+ fromMaybe err (fromResult @_ @(Nullify context a) (hunlabel hjust))
129161 where
130− tag = decodeTag htag
162+ err = error "Maybe.fromColumns: mismatch between tag and data"
131163
132− {-# INLINABLE fromColumns1 #-}
133− {-# INLINABLE toColumns1 #-}
134164
165+instance (EqTable a, context ~ Expr) => EqTable (MaybeTable context a) where
166+ eqTable = HMaybeTable
167+ { htag = hlabel (HIdentity Dict)
168+ , hjust = hlabel (eqTable @(Nullify context a))
169+ }
135170
136−instance
137− ( Table context a
138− , Labelable context, Nullifiable context
139− ) => Table context (MaybeTable a)
140− where
141− type Columns (MaybeTable a) = HMaybeTable (HLabel "Just" (Columns a))
142− type Context (MaybeTable a) = Context a
143171
144− toColumns = toColumns1 (hlabel labeler . toColumns)
145− fromColumns = fromColumns1 (fromColumns . hunlabel unlabeler)
172+instance (OrdTable a, context ~ Expr) => OrdTable (MaybeTable context a) where
173+ ordTable = HMaybeTable
174+ { htag = hlabel (HIdentity Dict)
175+ , hjust = hlabel (ordTable @(Nullify context a))
176+ }
146177
147178
148−instance
149− ( Labelable from, Nullifiable from
150− , Labelable to, Nullifiable to
151− , Recontextualize from to a b
152− ) => Recontextualize from to (MaybeTable a) (MaybeTable b)
179+instance (ToExprs exprs a, context ~ Expr) =>
180+ ToExprs (MaybeTable context exprs) (Maybe a)
153181
154182
155−isNothingTable :: MaybeTable a -> Expr Bool
183+-- | Check if a @MaybeTable@ is absent of any row. Like 'Data.Maybe.isNothing'.
184+isNothingTable :: MaybeTable Expr a -> Expr Bool
156185isNothingTable (MaybeTable tag _) = isNull tag
157186
158187
159−isJustTable :: MaybeTable a -> Expr Bool
188+-- | Check if a @MaybeTable@ contains a row. Like 'Data.Maybe.isJust'.
189+isJustTable :: MaybeTable Expr a -> Expr Bool
160190isJustTable (MaybeTable tag _) = isNonNull tag
161191
162192
163−maybeTable :: Table DB b => b -> (a -> b) -> MaybeTable a -> b
164−maybeTable b f ma@(MaybeTable _ a) = bool (f a) b (isNothingTable ma)
193+-- | Perform case analysis on a 'MaybeTable'. Like 'maybe'.
194+maybeTable :: Table Expr b => b -> (a -> b) -> MaybeTable Expr a -> b
195+maybeTable b f ma@(MaybeTable _ a) = bool (f (extract a)) b (isNothingTable ma)
196+{-# INLINABLE maybeTable #-}
197+
198+
199+-- | The null table. Like 'Nothing'.
200+nothingTable :: Table Expr a => MaybeTable Expr a
201+nothingTable = MaybeTable null (pure undefined)
165202
166203
167−nothingTable :: Table DB a => MaybeTable a
168−nothingTable = MaybeTable null undefined
204+-- | Lift any table into 'MaybeTable'. Like 'Just'. Note you can also use
205+-- 'pure'.
206+justTable :: a -> MaybeTable Expr a
207+justTable = MaybeTable mempty . pure
169208
170209
171−justTable :: a -> MaybeTable a
172−justTable = MaybeTable (nullify (litExpr IsJust))
210+-- | 'Data.Maybe.fromMaybe' for 'MaybeTable's.
211+fromMaybeTable :: Table Expr a => a -> MaybeTable Expr a -> a
212+fromMaybeTable fallback = maybeTable fallback id
173213
174214
175−($?) :: forall a b db. (DBType db, Nullabilizes db b)
176− => (a -> Expr b) -> MaybeTable a -> Expr (Maybe db)
177−f $? ma@(MaybeTable _ a) = case nullabilization @b of
178− Nullable -> boolExpr (f a) null (isNothingTable ma)
179− NonNullable -> boolExpr (nullify (f a)) null (isNothingTable ma)
215+-- | Project a single expression out of a 'MaybeTable'. You can think of this
216+-- operator like the '$' operator, but it also has the ability to return
217+-- @null@.
218+($?) :: forall a b. Sql DBType b
219+ => (a -> Expr b) -> MaybeTable Expr a -> Expr (N.Nullify b)
220+f $? ma@(MaybeTable _ a) = case nullable @b of
221+ Null -> boolExpr (f (extract a)) null (isNothingTable ma)
222+ NotNull -> boolExpr (nullify (f (extract a))) null (isNothingTable ma)
180223infixl 4 $?
224+
225+
226+-- | Lift an aggregating function to operate on a 'MaybeTable'.
227+-- @nothingTable@s and @justTable@s are grouped separately.
228+aggregateMaybeTable :: ()
229+ => (exprs -> aggregates)
230+ -> MaybeTable Expr exprs
231+ -> MaybeTable Aggregate aggregates
232+aggregateMaybeTable f (MaybeTable tag a) =
233+ MaybeTable (groupByExpr tag) (aggregateNullify f a)
234+
235+
236+-- | Construct a 'MaybeTable' in the 'Name' context. This can be useful if you
237+-- have a 'MaybeTable' that you are storing in a table and need to construct a
238+-- 'TableSchema'.
239+nameMaybeTable
240+ :: Name (Maybe MaybeTag)
241+ -- ^ The name of the column to track whether a row is a 'justTable' or
242+ -- 'nothingTable'.
243+ -> a
244+ -- ^ Names of the columns in @a@.
245+ -> MaybeTable Name a
246+nameMaybeTable tag = MaybeTable tag . pure
src/Rel8/Table/Name.hs+37−13
@@ -1,8 +1,12 @@
1+{-# language DataKinds #-}
12{-# language FlexibleContexts #-}
3+{-# language FlexibleInstances #-}
4+{-# language MultiParamTypeClasses #-}
25{-# language NamedFieldPuns #-}
36{-# language ScopedTypeVariables #-}
47{-# language TypeApplications #-}
58{-# language TypeFamilies #-}
9+{-# language UndecidableInstances #-}
610{-# language ViewPatterns #-}
711
812module Rel8.Table.Name
@@ -16,40 +20,60 @@ where
1620-- base
1721import Data.Foldable ( fold )
1822import Data.Functor.Const ( Const( Const ), getConst )
19−import Data.List.NonEmpty ( NonEmpty, intersperse )
23+import Data.List.NonEmpty ( NonEmpty, intersperse, nonEmpty )
24+import Data.Maybe ( fromMaybe )
2025import Prelude
2126
22−-- casing
23−import Text.Casing ( quietSnake )
24−
2527-- rel8
26−import Rel8.Kind.Labels ( renderLabels )
27−import Rel8.Schema.Context ( Name( Name ) )
2828import Rel8.Schema.HTable ( htabulate, htabulateA, hfield, hspecs )
29−import Rel8.Schema.Spec ( SSpec(..) )
30−import Rel8.Table ( Table, Columns, Context, fromColumns, toColumns )
29+import Rel8.Schema.Name ( Name( Name ) )
30+import Rel8.Schema.Spec ( Spec(..) )
31+import Rel8.Table ( Table(..) )
3132
3233
34+-- | Construct a table in the 'Name' context containing the names of all
35+-- columns. Nested column names will be combined with @/@.
36+--
37+-- See also: 'namesFromLabelsWith'.
3338namesFromLabels :: Table Name a => a
3439namesFromLabels = namesFromLabelsWith go
3540 where
36− go = fold . intersperse "/" . fmap quietSnake
41+ go = fold . intersperse "/"
3742
3843
44+-- | Construct a table in the 'Name' context containing the names of all
45+-- columns. The supplied function can be used to transform column names.
46+--
47+-- This function can be used to generically derive the columns for a
48+-- 'TableSchema'. For example,
49+--
50+-- @
51+-- myTableSchema :: TableSchema (MyTable Name)
52+-- myTableSchema = TableSchema
53+-- { columns = namesFromLabelsWith last
54+-- }
55+-- @
56+--
57+-- will construct a 'TableSchema' where each columns names exactly corresponds
58+-- to the name of the Haskell field.
3959namesFromLabelsWith :: Table Name a
4060 => (NonEmpty String -> String) -> a
4161namesFromLabelsWith f = fromColumns $ htabulate $ \field ->
4262 case hfield hspecs field of
43− SSpec {labels} -> Name (f (renderLabels labels))
63+ Spec {labels} -> Name (f (renderLabels labels))
4464
4565
4666showLabels :: forall a. Table (Context a) a => a -> [NonEmpty String]
4767showLabels _ = getConst $
4868 htabulateA @(Columns a) $ \field -> case hfield hspecs field of
49− SSpec {labels} -> Const [renderLabels labels]
69+ Spec {labels} -> Const (pure (renderLabels labels))
5070
5171
52−showNames :: forall a. Table Name a => a -> [String]
72+showNames :: forall a. Table Name a => a -> NonEmpty String
5373showNames (toColumns -> names) = getConst $
5474 htabulateA @(Columns a) $ \field -> case hfield names field of
55− Name name -> Const [name]
75+ Name name -> Const (pure name)
76+
77+
78+renderLabels :: [String] -> NonEmpty String
79+renderLabels labels = fromMaybe (pure "anon") (nonEmpty labels )
src/Rel8/Table/NonEmpty.hs+111−19
@@ -1,51 +1,143 @@
1+{-# language DataKinds #-}
2+{-# language FlexibleContexts #-}
13{-# language FlexibleInstances #-}
24{-# language MultiParamTypeClasses #-}
5+{-# language NamedFieldPuns #-}
6+{-# language ScopedTypeVariables #-}
37{-# language StandaloneKindSignatures #-}
8+{-# language TypeApplications #-}
49{-# language TypeFamilies #-}
510{-# language UndecidableInstances #-}
611
712module Rel8.Table.NonEmpty
813 ( NonEmptyTable(..)
9− , HNonEmptyTable
14+ , ($+)
15+ , nonEmptyTable
16+ , nameNonEmptyTable
1017 )
1118where
1219
1320-- base
21+import Data.Functor.Identity ( Identity( Identity ) )
1422import Data.Kind ( Type )
15−import Prelude
23+import Data.List.NonEmpty ( NonEmpty )
24+import Prelude hiding ( id )
1625
1726-- rel8
18−import Rel8.Expr.Array ( sappend1 )
19−import Rel8.Schema.Context ( DB( DB ) )
20−import Rel8.Schema.HTable.Context ( H )
27+import Rel8.Expr ( Expr )
28+import Rel8.Expr.Array ( sappend1, snonEmptyOf )
29+import Rel8.Schema.Dict ( Dict( Dict ) )
2130import Rel8.Schema.HTable.NonEmpty ( HNonEmptyTable )
22−import Rel8.Schema.HTable.Vectorize ( happend )
23−import Rel8.Table ( Table, Context, Columns, fromColumns, toColumns )
31+import Rel8.Schema.HTable.Vectorize
32+ ( hvectorize, hunvectorize
33+ , happend
34+ , hproject, hcolumn
35+ )
36+import qualified Rel8.Schema.Kind as K
37+import Rel8.Schema.Name ( Name( Name ) )
38+import Rel8.Schema.Null ( Nullity( Null, NotNull ) )
39+import Rel8.Schema.Result ( vectorizer, unvectorizer )
40+import Rel8.Schema.Spec ( Spec(..) )
41+import Rel8.Table
42+ ( Table, Context, Columns, fromColumns, toColumns
43+ , FromExprs, fromResult, toResult
44+ , Transpose
45+ )
2446import Rel8.Table.Alternative ( AltTable, (<|>:) )
25−import Rel8.Table.Recontextualize ( Recontextualize )
47+import Rel8.Table.Eq ( EqTable, eqTable )
48+import Rel8.Table.Ord ( OrdTable, ordTable )
49+import Rel8.Table.Projection
50+ ( Projectable, Projecting, Projection, project, apply
51+ )
52+import Rel8.Table.Serialize ( ToExprs )
53+
2654
55+-- | A @NonEmptyTable@ value contains one or more instances of @a@. You
56+-- construct @NonEmptyTable@s with 'Rel8.some' or 'nonEmptyAgg'.
57+type NonEmptyTable :: K.Context -> Type -> Type
58+newtype NonEmptyTable context a =
59+ NonEmptyTable (HNonEmptyTable (Columns a) (Context a))
2760
28−type NonEmptyTable :: Type -> Type
29−newtype NonEmptyTable a =
30− NonEmptyTable (HNonEmptyTable (Columns a) (H (Context a)))
3161
62+instance Projectable (NonEmptyTable context) where
63+ project f (NonEmptyTable a) = NonEmptyTable (hproject (apply f) a)
3264
33−instance Table context a => Table context (NonEmptyTable a) where
34− type Columns (NonEmptyTable a) = HNonEmptyTable (Columns a)
35− type Context (NonEmptyTable a) = Context a
65+
66+instance (Table context a, context ~ context') =>
67+ Table context' (NonEmptyTable context a)
68+ where
69+ type Columns (NonEmptyTable context a) = HNonEmptyTable (Columns a)
70+ type Context (NonEmptyTable context a) = Context a
71+ type FromExprs (NonEmptyTable context a) = NonEmpty (FromExprs a)
72+ type Transpose to (NonEmptyTable context a) =
73+ NonEmptyTable to (Transpose to a)
3674
3775 fromColumns = NonEmptyTable
3876 toColumns (NonEmptyTable a) = a
77+ fromResult = fmap (fromResult @_ @a) . hunvectorize unvectorizer
78+ toResult = hvectorize vectorizer . fmap (toResult @_ @a)
79+
80+
81+instance (EqTable a, context ~ Expr) =>
82+ EqTable (NonEmptyTable context a)
83+ where
84+ eqTable =
85+ hvectorize
86+ (\Spec {nullity} (Identity Dict) -> case nullity of
87+ Null -> Dict
88+ NotNull -> Dict)
89+ (Identity (eqTable @a))
90+
3991
92+instance (OrdTable a, context ~ Expr) =>
93+ OrdTable (NonEmptyTable context a)
94+ where
95+ ordTable =
96+ hvectorize
97+ (\Spec {nullity} (Identity Dict) -> case nullity of
98+ Null -> Dict
99+ NotNull -> Dict)
100+ (Identity (ordTable @a))
40101
41−instance Recontextualize from to a b =>
42− Recontextualize from to (NonEmptyTable a) (NonEmptyTable b)
43102
103+instance (ToExprs exprs a, context ~ Expr) =>
104+ ToExprs (NonEmptyTable context exprs) (NonEmpty a)
44105
45−instance AltTable NonEmptyTable where
106+
107+instance context ~ Expr => AltTable (NonEmptyTable context) where
46108 (<|>:) = (<>)
47109
48110
49−instance Table DB a => Semigroup (NonEmptyTable a) where
111+instance (Table Expr a, context ~ Expr) => Semigroup (NonEmptyTable context a)
112+ where
50113 NonEmptyTable as <> NonEmptyTable bs = NonEmptyTable $
51− happend (\_ _ (DB a) (DB b) -> DB (sappend1 a b)) as bs
114+ happend (const sappend1) as bs
115+
116+
117+-- | Project a single expression out of a 'NonEmptyTable'.
118+($+) :: Projecting a (Expr b)
119+ => Projection a (Expr b) -> NonEmptyTable Expr a -> Expr (NonEmpty b)
120+f $+ NonEmptyTable a = hcolumn $ hproject (apply f) a
121+infixl 4 $+
122+
123+
124+-- | Construct a @NonEmptyTable@ from a non-empty list of expressions.
125+nonEmptyTable :: Table Expr a => NonEmpty a -> NonEmptyTable Expr a
126+nonEmptyTable =
127+ NonEmptyTable .
128+ hvectorize (\Spec {info} -> snonEmptyOf info) .
129+ fmap toColumns
130+
131+
132+-- | Construct a 'NonEmptyTable' in the 'Name' context. This can be useful if
133+-- you have a 'NonEmptyTable' that you are storing in a table and need to
134+-- construct a 'TableSchema'.
135+nameNonEmptyTable
136+ :: Table Name a
137+ => a -- ^ The names of the columns of elements of the list.
138+ -> NonEmptyTable Name a
139+nameNonEmptyTable =
140+ NonEmptyTable .
141+ hvectorize (\_ (Identity (Name a)) -> Name a) .
142+ pure .
143+ toColumns
src/Rel8/Table/Null.hsnew file+147
@@ -0,0 +1,147 @@
1+{-# language DataKinds #-}
2+{-# language FlexibleContexts #-}
3+{-# language FlexibleInstances #-}
4+{-# language MultiParamTypeClasses #-}
5+{-# language ScopedTypeVariables #-}
6+{-# language StandaloneKindSignatures #-}
7+{-# language TypeApplications #-}
8+{-# language TypeFamilies #-}
9+{-# language UndecidableInstances #-}
10+
11+module Rel8.Table.Null
12+ ( NullTable(..)
13+ , nullableTable, nullTable, nullifyTable, unsafeUnnullifyTable
14+ , isNullTable, isNonNullTable
15+ , nameNullTable
16+ , toMaybeTable, toNullTable
17+ )
18+where
19+
20+-- base
21+import Data.Kind ( Type )
22+import Prelude hiding ( null, undefined )
23+
24+-- comonad
25+import Control.Comonad ( extract )
26+
27+-- rel8
28+import Rel8.Expr ( Expr )
29+import Rel8.Expr.Bool ( not_ )
30+import Rel8.Kind.Context ( Reifiable )
31+import qualified Rel8.Schema.Kind as K
32+import Rel8.Schema.Name ( Name )
33+import Rel8.Table
34+ ( Table, Columns, Context, fromColumns, toColumns
35+ , FromExprs, fromResult, toResult
36+ , Transpose
37+ )
38+import Rel8.Table.Alternative
39+ ( AltTable, (<|>:)
40+ , AlternativeTable, emptyTable
41+ )
42+import Rel8.Table.Bool ( bool )
43+import Rel8.Table.Eq ( EqTable, eqTable )
44+import Rel8.Table.Maybe ( MaybeTable, justTable, maybeTable, nothingTable )
45+import Rel8.Table.Nullify ( Nullify, isNull )
46+import Rel8.Table.Ord ( OrdTable, ordTable )
47+import Rel8.Table.Projection ( Projectable, project )
48+import Rel8.Table.Serialize ( ToExprs )
49+import Rel8.Table.Undefined ( undefined )
50+
51+
52+-- | @NullTable t@ is the table @t@, but where all the columns in @t@ have the
53+-- possibility of being 'Rel8.null'. This is very similar to
54+-- 'Rel8.MaybeTable', except that it does not use an extra tag field, so it
55+-- cannot distinguish between @Nothing@ and @Just Nothing@ if nested. In other
56+-- words, if all of the columns of the @t@ passed to @NullTable@ are already
57+-- nullable, then @NullTable@ has no effect.
58+type NullTable :: K.Context -> Type -> Type
59+newtype NullTable context a = NullTable (Nullify context a)
60+
61+
62+instance Projectable (NullTable context) where
63+ project f (NullTable a) = NullTable (project f a)
64+
65+
66+instance context ~ Expr => AltTable (NullTable context) where
67+ ma <|>: mb = bool ma mb (isNullTable ma)
68+
69+
70+instance context ~ Expr => AlternativeTable (NullTable context) where
71+ emptyTable = nullTable
72+
73+
74+instance (Table context a, Reifiable context, context ~ context') =>
75+ Table context' (NullTable context a)
76+ where
77+ type Columns (NullTable context a) = Columns (Nullify context a)
78+ type Context (NullTable context a) = Context (Nullify context a)
79+ type FromExprs (NullTable context a) = FromExprs (Nullify context a)
80+ type Transpose to (NullTable context a) = NullTable to (Transpose to a)
81+
82+ toColumns (NullTable a) = toColumns a
83+ fromColumns = NullTable . fromColumns
84+
85+ toResult = toResult @_ @(Nullify context a)
86+ fromResult = fromResult @_ @(Nullify context a)
87+
88+
89+instance (EqTable a, context ~ Expr) => EqTable (NullTable context a) where
90+ eqTable = eqTable @(Nullify context a)
91+
92+
93+instance (OrdTable a, context ~ Expr) => OrdTable (NullTable context a) where
94+ ordTable = ordTable @(Nullify context a)
95+
96+
97+instance (ToExprs exprs a, context ~ Expr) =>
98+ ToExprs (NullTable context exprs) (Maybe a)
99+
100+
101+-- | Check if any of the non-nullable fields of @a@ are 'Rel8.null' under the
102+-- 'NullTable'. Returns 'Rel8.false' if @a@ has no non-nullable fields.
103+isNullTable :: Table Expr a => NullTable Expr a -> Expr Bool
104+isNullTable (NullTable a) = isNull a
105+
106+
107+-- | The inverse of 'isNullTable'.
108+isNonNullTable :: Table Expr a => NullTable Expr a -> Expr Bool
109+isNonNullTable = not_ . isNullTable
110+
111+
112+-- | Like 'Rel8.nullable'.
113+nullableTable :: (Table Expr a, Table Expr b)
114+ => b -> (a -> b) -> NullTable Expr a -> b
115+nullableTable b f ma@(NullTable a) = bool (f (extract a)) b (isNullTable ma)
116+
117+
118+-- | The null table. Like 'Rel8.null'.
119+nullTable :: Table Expr a => NullTable Expr a
120+nullTable = NullTable (pure undefined)
121+
122+
123+-- | Lift any table into 'NullTable'. Like 'Rel8.nullify'.
124+nullifyTable :: a -> NullTable Expr a
125+nullifyTable = NullTable . pure
126+
127+
128+unsafeUnnullifyTable :: NullTable Expr a -> a
129+unsafeUnnullifyTable (NullTable a) = extract a
130+
131+
132+-- | Construct a 'NullTable' in the 'Name' context. This can be useful if you
133+-- have a 'NullTable' that you are storing in a table and need to construct a
134+-- 'TableSchema'.
135+nameNullTable :: a -> NullTable Name a
136+nameNullTable = NullTable . pure
137+
138+
139+-- | Convert a 'NullTable' to a 'MaybeTable'.
140+toMaybeTable :: Table Expr a => NullTable Expr a -> MaybeTable Expr a
141+toMaybeTable = nullableTable nothingTable justTable
142+
143+
144+-- | Convert a 'MaybeTable' to a 'NullTable'. Note that if the underlying @a@
145+-- has no non-nullable fields, this is a lossy conversion.
146+toNullTable :: Table Expr a => MaybeTable Expr a -> NullTable Expr a
147+toNullTable = maybeTable nullTable nullifyTable
src/Rel8/Table/Nullify.hsnew file+211
@@ -0,0 +1,211 @@
1+{-# language DataKinds #-}
2+{-# language FlexibleContexts #-}
3+{-# language FlexibleInstances #-}
4+{-# language LambdaCase #-}
5+{-# language MultiParamTypeClasses #-}
6+{-# language NamedFieldPuns #-}
7+{-# language ScopedTypeVariables #-}
8+{-# language StandaloneKindSignatures #-}
9+{-# language TypeApplications #-}
10+{-# language TypeFamilies #-}
11+{-# language UndecidableInstances #-}
12+
13+module Rel8.Table.Nullify
14+ ( Nullify
15+ , aggregateNullify
16+ , guard
17+ , isNull
18+ )
19+where
20+
21+-- base
22+import Control.Applicative ( liftA2 )
23+import Data.Functor.Const ( Const( Const ), getConst )
24+import Data.Functor.Identity ( runIdentity )
25+import Data.Kind ( Type )
26+import Prelude
27+
28+-- comonad
29+import Control.Comonad ( Comonad, duplicate, extract, ComonadApply, (<@>) )
30+
31+-- rel8
32+import Rel8.Aggregate ( Aggregate )
33+import Rel8.Expr ( Expr )
34+import Rel8.Expr.Bool ( (||.), false )
35+import qualified Rel8.Expr.Null as Expr
36+import Rel8.Kind.Context ( Reifiable, contextSing )
37+import Rel8.Schema.Context.Nullify
38+ ( Nullifiability( NAggregate, NExpr )
39+ , NonNullifiability
40+ , Nullifiable, nullifiability
41+ , nullifiableOrNot, absurd
42+ , guarder
43+ , nullifier
44+ , unnullifier
45+ )
46+import Rel8.Schema.Dict ( Dict( Dict ) )
47+import Rel8.Schema.HTable ( HTable )
48+import Rel8.Schema.HTable.Nullify
49+ ( HNullify, hnulls, hnullify, hunnullify
50+ , hguard
51+ , hproject
52+ )
53+import qualified Rel8.Schema.Kind as K
54+import Rel8.Schema.Null ( Nullity( NotNull, Null ) )
55+import qualified Rel8.Schema.Result as R
56+import Rel8.Table
57+ ( Table, Columns, Context, toColumns, fromColumns
58+ , FromExprs, fromResult, toResult
59+ , Transpose
60+ )
61+import Rel8.Schema.Spec ( Spec( Spec, nullity ) )
62+import Rel8.Table.Eq ( EqTable, eqTable )
63+import Rel8.Table.Ord ( OrdTable, ordTable )
64+import Rel8.Table.Projection ( Projectable, apply, project )
65+
66+-- semigroupoids
67+import Data.Functor.Apply ( Apply, (<.>), liftF2 )
68+import Data.Functor.Bind ( Bind, (>>-) )
69+import Data.Functor.Extend ( Extend, duplicated )
70+
71+
72+type Nullify :: K.Context -> Type -> Type
73+data Nullify context a
74+ = Table (Nullifiability context) a
75+ | Fields (NonNullifiability context) (HNullify (Columns a) (Context a))
76+
77+
78+instance Projectable (Nullify context) where
79+ project f = \case
80+ Table nullifiable a -> Table nullifiable (fromColumns (apply f (toColumns a)))
81+ Fields nonNullifiable a -> Fields nonNullifiable (hproject (apply f) a)
82+
83+
84+instance Nullifiable context => Functor (Nullify context) where
85+ fmap f = \case
86+ Table nullifiable a -> Table nullifiable (f a)
87+ Fields notNullifiable _ -> absurd nullifiability notNullifiable
88+
89+
90+instance Nullifiable context => Foldable (Nullify context) where
91+ foldMap f = \case
92+ Table _ a -> f a
93+ Fields notNullifiable _ -> absurd nullifiability notNullifiable
94+
95+
96+instance Nullifiable context => Traversable (Nullify context) where
97+ traverse f = \case
98+ Table nullifiable a -> Table nullifiable <$> f a
99+ Fields notNullifiable _ -> absurd nullifiability notNullifiable
100+
101+
102+instance Nullifiable context => Apply (Nullify context) where
103+ liftF2 f = \case
104+ Table nullifiable a -> \case
105+ Table _ b -> Table nullifiable (f a b)
106+ Fields notNullifiable _ -> absurd nullifiable notNullifiable
107+ Fields notNullifiable _ -> absurd nullifiability notNullifiable
108+
109+
110+instance Nullifiable context => Applicative (Nullify context) where
111+ pure = Table nullifiability
112+ liftA2 = liftF2
113+
114+
115+instance Nullifiable context => Bind (Nullify context) where
116+ Table _ a >>- f = f a
117+ Fields notNullifiable _ >>- _ = absurd nullifiability notNullifiable
118+
119+
120+instance Nullifiable context => Monad (Nullify context) where
121+ (>>=) = (>>-)
122+
123+
124+instance Nullifiable context => Extend (Nullify context) where
125+ duplicated = \case
126+ Table nullifiable a -> Table nullifiable (Table nullifiable a)
127+ Fields notNullifiable _ -> absurd nullifiability notNullifiable
128+
129+
130+instance Nullifiable context => Comonad (Nullify context) where
131+ extract = \case
132+ Table _ a -> a
133+ Fields notNullifiable _ -> absurd nullifiability notNullifiable
134+ duplicate = duplicated
135+
136+
137+instance Nullifiable context => ComonadApply (Nullify context) where
138+ (<@>) = (<.>)
139+
140+
141+instance (Table context a, Reifiable context, context ~ context') =>
142+ Table context' (Nullify context a)
143+ where
144+ type Columns (Nullify context a) = HNullify (Columns a)
145+ type Context (Nullify context a) = Context a
146+ type FromExprs (Nullify context a) = Maybe (FromExprs a)
147+ type Transpose to (Nullify context a) = Nullify to (Transpose to a)
148+
149+ fromColumns = case nullifiableOrNot contextSing of
150+ Left notNullifiable -> Fields notNullifiable
151+ Right nullifiable ->
152+ Table nullifiable .
153+ fromColumns .
154+ runIdentity .
155+ hunnullify (\spec -> pure . unnullifier nullifiable spec)
156+
157+ toColumns = \case
158+ Table nullifiable a -> hnullify (nullifier nullifiable) (toColumns a)
159+ Fields _ a -> a
160+
161+ fromResult = fmap (fromResult @_ @a) . hunnullify R.unnullifier
162+
163+ toResult =
164+ maybe (hnulls (const R.null)) (hnullify R.nullifier) .
165+ fmap (toResult @_ @a)
166+
167+
168+instance (EqTable a, context ~ Expr) => EqTable (Nullify context a) where
169+ eqTable = hnullify (\_ Dict -> Dict) (eqTable @a)
170+
171+
172+instance (OrdTable a, context ~ Expr) => OrdTable (Nullify context a) where
173+ ordTable = hnullify (\_ Dict -> Dict) (ordTable @a)
174+
175+
176+aggregateNullify :: ()
177+ => (exprs -> aggregates)
178+ -> Nullify Expr exprs
179+ -> Nullify Aggregate aggregates
180+aggregateNullify f = \case
181+ Table _ a -> Table NAggregate (f a)
182+ Fields notNullifiable _ -> absurd NExpr notNullifiable
183+
184+
185+guard :: (Reifiable context, HTable t)
186+ => context tag
187+ -> (tag -> Bool)
188+ -> (Expr tag -> Expr Bool)
189+ -> HNullify t context
190+ -> HNullify t context
191+guard tag isNonNull isNonNullExpr =
192+ hguard (guarder contextSing tag isNonNull isNonNullExpr)
193+
194+
195+isNull :: forall a. Table Expr a => Nullify Expr a -> Expr Bool
196+isNull =
197+ maybe false getAny .
198+ getConst .
199+ hunnullify (\Spec {nullity} a -> Const $ case nullity of
200+ NotNull -> Just $ Any $ Expr.isNull a
201+ Null -> Nothing) .
202+ toColumns
203+
204+
205+newtype Any = Any
206+ { getAny :: Expr Bool
207+ }
208+
209+
210+instance Semigroup Any where
211+ Any a <> Any b = Any (a ||. b)
src/Rel8/Table/Opaleye.hs+97−76
@@ -1,129 +1,150 @@
1+{-# language BlockArguments #-}
2+{-# language DataKinds #-}
13{-# language DisambiguateRecordFields #-}
24{-# language FlexibleContexts #-}
35{-# language NamedFieldPuns #-}
6+{-# language RankNTypes #-}
47{-# language TypeFamilies #-}
58{-# language ViewPatterns #-}
69
10+{-# options_ghc -Wno-deprecations #-}
11+
712module Rel8.Table.Opaleye
813 ( aggregator
14+ , attributes
915 , binaryspec
1016 , distinctspec
17+ , exprs
18+ , exprsWithNames
1119 , table
1220 , tableFields
1321 , unpackspec
1422 , valuesspec
23+ , view
24+ , castTable
1525 )
1626where
1727
1828-- base
19−import Prelude hiding ( undefined )
29+import Data.Functor.Const ( Const( Const ), getConst )
30+import Data.List.NonEmpty ( NonEmpty )
31+import Prelude
2032
2133-- opaleye
34+import qualified Opaleye.Adaptors as Opaleye
35+import qualified Opaleye.Field as Opaleye ( Field_ )
2236import qualified Opaleye.Internal.Aggregate as Opaleye
23−import qualified Opaleye.Internal.Binary as Opaleye
24−import qualified Opaleye.Internal.Distinct as Opaleye
2537import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
26−import qualified Opaleye.Internal.PackMap as Opaleye
27−import qualified Opaleye.Internal.Unpackspec as Opaleye
2838import qualified Opaleye.Internal.Values as Opaleye
29−import qualified Opaleye.Internal.Table as Opaleye
39+import qualified Opaleye.Table as Opaleye
3040
3141-- profunctors
3242import Data.Profunctor ( dimap, lmap )
3343
3444-- rel8
35−import Rel8.Aggregate ( Aggregate( Aggregate ) )
45+import Rel8.Aggregate ( Aggregate( Aggregate ), Aggregates )
46+import Rel8.Expr ( Expr )
3647import Rel8.Expr.Opaleye
37− ( scastExpr
38− , fromPrimExpr, toPrimExpr
39− , traversePrimExpr
40− , fromColumn, toColumn
48+ ( fromPrimExpr, toPrimExpr
49+ , scastExpr, traverseFieldP
4150 )
42−import Rel8.Kind.Necessity ( SNecessity( SRequired, SOptional ) )
43−import Rel8.Schema.Context ( DB(..), Insertion(..), Name(..) )
44−import Rel8.Schema.HTable ( htabulateA, hfield, htraverse, hspecs )
45−import Rel8.Schema.Spec ( SSpec(..) )
46−import Rel8.Schema.Table ( TableSchema(..) )
51+import Rel8.Schema.HTable ( htabulateA, hfield, hspecs, htabulate,
52+ htraverseP, htraversePWithField )
53+import Rel8.Schema.Name ( Name( Name ), Selects, ppColumn )
54+import Rel8.Schema.Spec ( Spec(..) )
55+import Rel8.Schema.Table ( TableSchema(..), ppTable )
4756import Rel8.Table ( Table, fromColumns, toColumns )
48−import Rel8.Table.Recontextualize ( Selects, Inserts )
49−import Rel8.Table.Undefined ( undefined )
57+import Rel8.Type.Information ( typeName )
5058
5159-- semigroupoids
5260import Data.Functor.Apply ( WrappedApplicative(..) )
61+import Data.Profunctor.Product ( ProductProfunctor )
62+
63+
64+aggregator :: Aggregates aggregates exprs => Opaleye.Aggregator aggregates exprs
65+aggregator = dimap toColumns fromColumns $
66+ htraverseP $
67+ lmap (\(Aggregate a) -> (a, ())) Opaleye.aggregatorApply
68+
69+
70+attributes :: Selects names exprs => TableSchema names -> exprs
71+attributes schema@TableSchema {columns} = fromColumns $ htabulate $ \field ->
72+ case hfield (toColumns columns) field of
73+ Name column -> fromPrimExpr $ Opaleye.ConstExpr $
74+ Opaleye.OtherLit $
75+ show (ppTable schema) <> "." <> show (ppColumn column)
76+
77+
78+fromOpaleyespec :: (ProductProfunctor p, Table Expr a)
79+ => p (Opaleye.Field_ n x) (Opaleye.Field_ n x)
80+ -> p a a
81+fromOpaleyespec x =
82+ dimap toColumns fromColumns (htraverseP (traverseFieldP x))
5383
5484
55−aggregator :: Opaleye.Aggregator (Aggregate exprs) exprs
56−aggregator = Opaleye.Aggregator $ Opaleye.PackMap $
57− \f (Aggregate (Opaleye.Aggregator (Opaleye.PackMap inner))) -> inner f ()
85+binaryspec :: Table Expr a => Opaleye.Binaryspec a a
86+binaryspec = fromOpaleyespec Opaleye.binaryspecField
5887
5988
60−binaryspec :: Table DB a => Opaleye.Binaryspec a a
61−binaryspec = Opaleye.Binaryspec $ Opaleye.PackMap $ \f (as, bs) ->
62− fmap fromColumns $ unwrapApplicative $ htabulateA $ \field ->
63− WrapApplicative $
64− case (hfield (toColumns as) field, hfield (toColumns bs) field) of
65− (DB a, DB b) -> DB . fromPrimExpr <$> f (toPrimExpr a, toPrimExpr b)
89+distinctspec :: Table Expr a => Opaleye.Distinctspec a a
90+distinctspec = fromOpaleyespec Opaleye.distinctspecField
6691
6792
68−distinctspec :: Table DB a => Opaleye.Distinctspec a a
69−distinctspec =
70− Opaleye.Distinctspec $ Opaleye.Aggregator $ Opaleye.PackMap $ \f ->
71− fmap fromColumns .
72− unwrapApplicative .
73− htraverse
74− (\(DB a) ->
75− WrapApplicative $ DB . fromPrimExpr <$> f (Nothing, toPrimExpr a)) .
76− toColumns
93+exprs :: Table Expr a => a -> NonEmpty Opaleye.PrimExpr
94+exprs (toColumns -> as) = getConst $ htabulateA $ \field ->
95+ case hfield as field of
96+ expr -> Const (pure (toPrimExpr expr))
7797
7898
79−table ::(Selects names exprs, Inserts exprs inserts)
80− => TableSchema names -> Opaleye.Table inserts exprs
99+exprsWithNames :: Selects names exprs
100+ => names -> exprs -> NonEmpty (String, Opaleye.PrimExpr)
101+exprsWithNames names as = getConst $ htabulateA $ \field ->
102+ case (hfield (toColumns names) field, hfield (toColumns as) field) of
103+ (Name name, expr) -> Const (pure (name, toPrimExpr expr))
104+
105+
106+table :: Selects names exprs => TableSchema names -> Opaleye.Table exprs exprs
81107table (TableSchema name schema columns) =
82− Opaleye.Table qualified (tableFields columns)
83− where
84− qualified = case schema of
85− Nothing -> name
86− Just qualifier -> qualifier <> "." <> name
108+ case schema of
109+ Nothing -> Opaleye.table name (tableFields columns)
110+ Just schemaName -> Opaleye.tableWithSchema schemaName name (tableFields columns)
87111
88112
89−tableFields :: (Selects names exprs, Inserts exprs inserts)
90− => names -> Opaleye.TableFields inserts exprs
113+tableFields :: Selects names exprs
114+ => names -> Opaleye.TableFields exprs exprs
91115tableFields (toColumns -> names) = dimap toColumns fromColumns $
92116 unwrapApplicative $ htabulateA $ \field -> WrapApplicative $
93− case hfield hspecs field of
94− specs -> case hfield names field of
95− name -> lmap (`hfield` field) (go specs name)
117+ case hfield names field of
118+ name -> lmap (`hfield` field) (go name)
96119 where
97− go :: SSpec spec -> Name spec -> Opaleye.TableFields (Insertion spec) (DB spec)
98− go SSpec {necessity, info, nullability} (Name name) =
99− case necessity of
100− SRequired ->
101− lmap (\(RequiredInsert a) -> toColumn $ toPrimExpr a) $
102− DB . scastExpr nullability info . fromPrimExpr . fromColumn <$>
103− Opaleye.requiredTableField name
104− SOptional ->
105− lmap (\(OptionalInsert ma) -> toColumn . toPrimExpr <$> ma) $
106− DB . scastExpr nullability info . fromPrimExpr . fromColumn <$>
107− Opaleye.optionalTableField name
108−
109−
110−unpackspec :: Table DB a => Opaleye.Unpackspec a a
111−unpackspec = Opaleye.Unpackspec $ Opaleye.PackMap $ \f ->
112− fmap fromColumns .
113− unwrapApplicative .
114− htraverse (\(DB a) -> WrapApplicative $ DB <$> traversePrimExpr f a) .
115− toColumns
120+ go :: Name a -> Opaleye.TableFields (Expr a) (Expr a)
121+ go (Name name) =
122+ traverseFieldP $
123+ Opaleye.requiredTableField name
124+
125+
126+unpackspec :: Table Expr a => Opaleye.Unpackspec a a
127+unpackspec = fromOpaleyespec Opaleye.unpackspecField
116128{-# INLINABLE unpackspec #-}
117129
118130
119−valuesspec :: Table DB a => Opaleye.ValuesspecSafe a a
120−valuesspec = Opaleye.ValuesspecSafe (toPackMap undefined) unpackspec
131+valuesspec :: Table Expr a => Opaleye.Valuesspec a a
132+valuesspec = dimap toColumns fromColumns $
133+ htraversePWithField (traverseFieldP . Opaleye.valuesspecFieldType . typeName)
134+ where typeName = Rel8.Type.Information.typeName . info . hfield hspecs
135+
136+
137+view :: Selects names exprs => names -> exprs
138+view columns = fromColumns $ htabulate $ \field ->
139+ case hfield (toColumns columns) field of
140+ Name column -> fromPrimExpr $ Opaleye.BaseTableAttrExpr column
121141
122142
123−toPackMap :: Table DB a
124− => a -> Opaleye.PackMap Opaleye.PrimExpr Opaleye.PrimExpr () a
125−toPackMap as = Opaleye.PackMap $ \f () ->
126− fmap fromColumns $
127− unwrapApplicative .
128− htraverse (\(DB a) -> WrapApplicative $ DB <$> traversePrimExpr f a) $
129− toColumns as
143+-- | Transform a table by adding 'CAST' to all columns. This is most useful for
144+-- finalising a SELECT or RETURNING statement, guaranteed that the output
145+-- matches what is encoded in each columns TypeInformation.
146+castTable :: Table Expr a => a -> a
147+castTable (toColumns -> as) = fromColumns $ htabulate \field ->
148+ case hfield hspecs field of
149+ Spec {info} -> case hfield as field of
150+ expr -> scastExpr info expr
src/Rel8/Table/Ord.hs+83−49
@@ -1,120 +1,154 @@
1+{-# language AllowAmbiguousTypes #-}
12{-# language DataKinds #-}
3+{-# language DefaultSignatures #-}
4+{-# language DisambiguateRecordFields #-}
5+{-# language FlexibleContexts #-}
26{-# language FlexibleInstances #-}
3−{-# language NamedFieldPuns #-}
47{-# language ScopedTypeVariables #-}
58{-# language StandaloneKindSignatures #-}
69{-# language TypeApplications #-}
710{-# language TypeFamilies #-}
11+{-# language TypeOperators #-}
812{-# language UndecidableInstances #-}
9−{-# language UndecidableSuperClasses #-}
1013{-# language ViewPatterns #-}
1114
1215module Rel8.Table.Ord
13− ( OrdTable, (<:), (<=:), (>:), (>=:), least, greatest
16+ ( OrdTable( ordTable ), (<:), (<=:), (>:), (>=:), least, greatest
1417 )
1518where
1619
1720-- base
1821import Data.Functor.Const ( Const( Const ), getConst )
1922import Data.Kind ( Constraint, Type )
23+import GHC.Generics ( Rep )
2024import Prelude hiding ( seq )
2125
2226-- rel8
2327import Rel8.Expr ( Expr )
2428import Rel8.Expr.Bool ( (||.), (&&.), false, true )
25−import Rel8.Expr.Eq ( seq )
26−import Rel8.Expr.Ord ( slt, sgt)
27−import Rel8.Opaque ( Opaque )
28−import Rel8.Schema.Context ( DB( DB ) )
29+import Rel8.Expr.Eq ( (==.) )
30+import Rel8.Expr.Ord ( (<.), (>.) )
31+import Rel8.FCF ( Eval, Exp )
32+import Rel8.Generic.Record ( Record )
33+import Rel8.Generic.Table.Record ( GTable, GColumns, gtable )
2934import Rel8.Schema.Dict ( Dict( Dict ) )
30−import Rel8.Schema.HTable
31− ( HConstrainTable
32− , htabulateA, hfield
33− , hdicts, hspecs
34− )
35−import Rel8.Schema.Spec ( SSpec(..) )
36−import Rel8.Schema.Spec.ConstrainDBType ( ConstrainDBType )
37−import Rel8.Table ( Columns, toColumns )
35+import Rel8.Schema.HTable ( htabulateA, hfield )
36+import Rel8.Schema.HTable.Identity ( HIdentity( HIdentity ) )
37+import Rel8.Schema.Null (Sql)
38+import Rel8.Table ( Columns, toColumns, TColumns )
3839import Rel8.Table.Bool ( bool )
3940import Rel8.Table.Eq ( EqTable )
4041import Rel8.Type.Ord ( DBOrd )
4142
4243
44+-- | The class of 'Table's that can be ordered. Ordering on tables is defined
45+-- by their lexicographic ordering of all columns, so this class means "all
46+-- columns in a 'Table' have an instance of 'DBOrd'".
4347type OrdTable :: Type -> Constraint
44−class
45− ( EqTable a
46− , HConstrainTable (Columns a) (ConstrainDBType DBOrd)
47− ) => OrdTable a
48+class EqTable a => OrdTable a where
49+ ordTable :: Columns a (Dict (Sql DBOrd))
50+
51+ default ordTable ::
52+ ( GTable TOrdTable TColumns (Rep (Record a))
53+ , Columns a ~ GColumns TColumns (Rep (Record a))
54+ )
55+ => Columns a (Dict (Sql DBOrd))
56+ ordTable = gtable @TOrdTable @TColumns @(Rep (Record a)) table
57+ where
58+ table (_ :: proxy x) = ordTable @x
59+
60+
61+data TOrdTable :: Type -> Exp Constraint
62+type instance Eval (TOrdTable a) = OrdTable a
63+
64+
65+instance Sql DBOrd a => OrdTable (Expr a) where
66+ ordTable = HIdentity Dict
67+
68+
69+instance (OrdTable a, OrdTable b) => OrdTable (a, b)
70+
71+
72+instance (OrdTable a, OrdTable b, OrdTable c) => OrdTable (a, b, c)
73+
74+
75+instance (OrdTable a, OrdTable b, OrdTable c, OrdTable d) => OrdTable (a, b, c, d)
76+
77+
78+instance (OrdTable a, OrdTable b, OrdTable c, OrdTable d, OrdTable e) =>
79+ OrdTable (a, b, c, d, e)
80+
81+
4882instance
49− ( EqTable a
50− , HConstrainTable (Columns a) (ConstrainDBType DBOrd)
51− ) => OrdTable a
52−instance {-# OVERLAPPING #-} OrdTable Opaque
83+ ( OrdTable a, OrdTable b, OrdTable c, OrdTable d, OrdTable e, OrdTable f
84+ )
85+ => OrdTable (a, b, c, d, e, f)
86+
87+
88+instance
89+ ( OrdTable a, OrdTable b, OrdTable c, OrdTable d, OrdTable e, OrdTable f
90+ , OrdTable g
91+ )
92+ => OrdTable (a, b, c, d, e, f, g)
5393
5494
95+-- | Test if one 'Table' sorts before another. Corresponds to comparing all
96+-- columns with '<'.
5597(<:) :: forall a. OrdTable a => a -> a -> Expr Bool
5698(toColumns -> as) <: (toColumns -> bs) =
5799 foldr @[] go false $ getConst $ htabulateA $ \field ->
58100 case (hfield as field, hfield bs field) of
59− (DB a, DB b) -> case hfield dicts field of
60− Dict -> case hfield specs field of
61− SSpec {nullability} ->
62− Const [(slt nullability a b, seq nullability a b)]
101+ (a, b) -> case hfield (ordTable @a) field of
102+ Dict -> Const [(a <. b, a ==. b)]
63103 where
64− dicts = hdicts @(Columns a) @(ConstrainDBType DBOrd)
65− specs = hspecs @(Columns a)
66104 go (lt, eq) a = lt ||. (eq &&. a)
67105infix 4 <:
68106
69107
108+-- | Test if one 'Table' sorts before, or is equal to, another. Corresponds to
109+-- comparing all columns with '<='.
70110(<=:) :: forall a. OrdTable a => a -> a -> Expr Bool
71111(toColumns -> as) <=: (toColumns -> bs) =
72112 foldr @[] go true $ getConst $ htabulateA $ \field ->
73113 case (hfield as field, hfield bs field) of
74− (DB a, DB b) -> case hfield dicts field of
75− Dict -> case hfield specs field of
76− SSpec {nullability} ->
77− Const [(slt nullability a b, seq nullability a b)]
114+ (a, b) -> case hfield (ordTable @a) field of
115+ Dict -> Const [(a <. b, a ==. b)]
78116 where
79− dicts = hdicts @(Columns a) @(ConstrainDBType DBOrd)
80− specs = hspecs @(Columns a)
81117 go (lt, eq) a = lt ||. (eq &&. a)
82118infix 4 <=:
83119
84120
121+-- | Test if one 'Table' sorts after another. Corresponds to comparing all
122+-- columns with '>'.
85123(>:) :: forall a. OrdTable a => a -> a -> Expr Bool
86124(toColumns -> as) >: (toColumns -> bs) =
87125 foldr @[] go false $ getConst $ htabulateA $ \field ->
88126 case (hfield as field, hfield bs field) of
89− (DB a, DB b) -> case hfield dicts field of
90− Dict -> case hfield specs field of
91− SSpec {nullability} ->
92− Const [(slt nullability a b, seq nullability a b)]
127+ (a, b) -> case hfield (ordTable @a) field of
128+ Dict -> Const [(a >. b, a ==. b)]
93129 where
94− dicts = hdicts @(Columns a) @(ConstrainDBType DBOrd)
95− specs = hspecs @(Columns a)
96130 go (gt, eq) a = gt ||. (eq &&. a)
97131infix 4 >:
98132
99133
134+-- | Test if one 'Table' sorts after another. Corresponds to comparing all
135+-- columns with '>='.
100136(>=:) :: forall a. OrdTable a => a -> a -> Expr Bool
101137(toColumns -> as) >=: (toColumns -> bs) =
102138 foldr @[] go true $ getConst $ htabulateA $ \field ->
103139 case (hfield as field, hfield bs field) of
104− (DB a, DB b) -> case hfield dicts field of
105− Dict -> case hfield specs field of
106− SSpec {nullability} ->
107− Const [(sgt nullability a b, seq nullability a b)]
140+ (a, b) -> case hfield (ordTable @a) field of
141+ Dict -> Const [(a >. b, a ==. b)]
108142 where
109− dicts = hdicts @(Columns a) @(ConstrainDBType DBOrd)
110− specs = hspecs @(Columns a)
111143 go (gt, eq) a = gt ||. (eq &&. a)
112144infix 4 >=:
113145
114146
147+-- | Given two 'Table's, return the table that sorts before the other.
115148least :: OrdTable a => a -> a -> a
116−least a b = bool a b (a <: b)
149+least a b = bool b a (a <: b)
117150
118151
152+-- | Given two 'Table's, return the table that sorts after the other.
119153greatest :: OrdTable a => a -> a -> a
120−greatest a b = bool a b (a >: b)
154+greatest a b = bool b a (a >: b)
src/Rel8/Table/Order.hs+20−20
@@ -1,3 +1,4 @@
1+{-# language DataKinds #-}
12{-# language NamedFieldPuns #-}
23{-# language ScopedTypeVariables #-}
34{-# language TypeApplications #-}
@@ -17,34 +18,33 @@ import Prelude
1718-- rel8
1819import Rel8.Expr.Order ( asc, desc, nullsFirst, nullsLast )
1920import Rel8.Order ( Order )
20−import Rel8.Schema.Context ( unDB )
2121import Rel8.Schema.Dict ( Dict( Dict ) )
22−import Rel8.Schema.HTable (htabulateA, hfield, hdicts, hspecs)
23−import Rel8.Schema.Nullability ( Nullability( Nullable, NonNullable ) )
24−import Rel8.Schema.Spec ( SSpec(..) )
25−import Rel8.Schema.Spec.ConstrainDBType ( ConstrainDBType )
26−import Rel8.Table
27−import Rel8.Table.Ord
28−import Rel8.Type.Ord
22+import Rel8.Schema.HTable (htabulateA, hfield, hspecs)
23+import Rel8.Schema.Null ( Nullity( Null, NotNull ) )
24+import Rel8.Schema.Spec ( Spec( Spec, nullity ) )
25+import Rel8.Table ( Columns, toColumns )
26+import Rel8.Table.Ord ( OrdTable, ordTable )
2927
3028
29+-- | Construct an 'Order' for a 'Table' by sorting all columns into ascending
30+-- orders (any nullable columns will be sorted with @NULLS FIRST@).
3131ascTable :: forall a. OrdTable a => Order a
3232ascTable = contramap toColumns $ getConst $
3333 htabulateA @(Columns a) $ \field -> case hfield hspecs field of
34− SSpec {nullability} -> case hfield ords field of
35− Dict -> Const $ unDB . (`hfield` field) >$< case nullability of
36− Nullable -> nullsFirst asc
37− NonNullable -> asc
38− where
39− ords = hdicts @(Columns a) @(ConstrainDBType DBOrd)
34+ Spec {nullity} -> case hfield (ordTable @a) field of
35+ Dict -> Const $ (`hfield` field) >$<
36+ case nullity of
37+ Null -> nullsFirst asc
38+ NotNull -> asc
4039
4140
41+-- | Construct an 'Order' for a 'Table' by sorting all columns into descending
42+-- orders (any nullable columns will be sorted with @NULLS LAST@).
4243descTable :: forall a. OrdTable a => Order a
4344descTable = contramap toColumns $ getConst $
4445 htabulateA @(Columns a) $ \field -> case hfield hspecs field of
45− SSpec {nullability} -> case hfield ords field of
46− Dict -> Const $ unDB . (`hfield` field) >$< case nullability of
47− Nullable -> nullsLast desc
48− NonNullable -> desc
49− where
50− ords = hdicts @(Columns a) @(ConstrainDBType DBOrd)
46+ Spec {nullity} -> case hfield (ordTable @a) field of
47+ Dict -> Const $ (`hfield` field) >$<
48+ case nullity of
49+ Null -> nullsLast desc
50+ NotNull -> desc
src/Rel8/Table/Projection.hsnew file+73
@@ -0,0 +1,73 @@
1+{-# language FlexibleContexts #-}
2+{-# language FlexibleInstances #-}
3+{-# language MonoLocalBinds #-}
4+{-# language MultiParamTypeClasses #-}
5+{-# language StandaloneKindSignatures #-}
6+{-# language UndecidableInstances #-}
7+
8+module Rel8.Table.Projection
9+ ( Projection
10+ , Projectable( project )
11+ , Biprojectable( biproject )
12+ , Projecting
13+ , apply
14+ )
15+where
16+
17+-- base
18+import Data.Kind ( Constraint, Type )
19+import Prelude
20+
21+-- rel8
22+import Rel8.Schema.Field ( Field( Field ), fields )
23+import Rel8.Schema.HTable ( hfield, htabulate )
24+import Rel8.Table ( Columns, Context, Transpose, toColumns )
25+import Rel8.Table.Transpose ( Transposes )
26+
27+
28+-- | The constraint @'Projecting' a b@ ensures that @'Projection' a b@ is a
29+-- usable 'Projection'.
30+type Projecting :: Type -> Type -> Constraint
31+class
32+ ( Transposes (Context a) (Field a) a (Transpose (Field a) a)
33+ , Transposes (Context a) (Field a) b (Transpose (Field a) b)
34+ )
35+ => Projecting a b
36+instance
37+ ( Transposes (Context a) (Field a) a (Transpose (Field a) a)
38+ , Transposes (Context a) (Field a) b (Transpose (Field a) b)
39+ )
40+ => Projecting a b
41+
42+
43+-- | A @'Projection' a b@s is a special type of function @a -> b@ whereby the
44+-- resulting @b@ is guaranteed to be composed only from columns contained in
45+-- @a@.
46+type Projection :: Type -> Type -> Type
47+type Projection a b = Transpose (Field a) a -> Transpose (Field a) b
48+
49+
50+-- | @'Projectable' f@ means that @f@ is a kind of functor on 'Rel8.Table's
51+-- that allows the mapping of a 'Projection' over its underlying columns.
52+type Projectable :: (Type -> Type) -> Constraint
53+class Projectable f where
54+ -- | Map a 'Projection' over @f@.
55+ project :: Projecting a b
56+ => Projection a b -> f a -> f b
57+
58+
59+-- | @'Biprojectable' p@ means that @p@ is a kind of bifunctor on
60+-- 'Rel8.Table's that allows the mapping of a pair of 'Projection's over its
61+-- underlying columns.
62+type Biprojectable :: (Type -> Type -> Type) -> Constraint
63+class Biprojectable p where
64+ -- | Map a pair of 'Projection's over @p@.
65+ biproject :: (Projecting a b, Projecting c d)
66+ => Projection a b -> Projection c d -> p a c -> p b d
67+
68+
69+apply :: Projecting a b
70+ => Projection a b -> Columns a context -> Columns b context
71+apply f a = case toColumns (f fields) of
72+ bs -> htabulate $ \field -> case hfield bs field of
73+ Field field' -> hfield a field'
src/Rel8/Table/Recontextualize.hsdeleted−162
@@ -1,162 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language FlexibleContexts #-}
3−{-# language FlexibleInstances #-}
4−{-# language FunctionalDependencies #-}
5−{-# language StandaloneKindSignatures #-}
6−{-# language TypeFamilies #-}
7−{-# language UndecidableInstances #-}
8−{-# language UndecidableSuperClasses #-}
9−
10−module Rel8.Table.Recontextualize
11− ( Recontextualize
12− , Aggregates
13− , Encodes
14− , Selects
15− , Inserts
16− )
17−where
18−
19−-- base
20−import Data.Functor.Identity ( Identity )
21−import Data.Kind ( Constraint, Type )
22−import Prelude ()
23−
24−-- rel8
25−import Rel8.Aggregate ( Aggregate )
26−import Rel8.Expr ( Expr )
27−import Rel8.Opaque ( Opaque, Opaque1 )
28−import Rel8.Schema.Context ( Aggregation, DB, Insertion, Name, Result )
29−import Rel8.Schema.Context.Label ( Labelable )
30−import Rel8.Schema.HTable ( HTable )
31−import Rel8.Schema.HTable.Context ( H )
32−import Rel8.Schema.Nullability ( Nullabilizes )
33−import Rel8.Schema.Spec ( KnownSpec )
34−import qualified Rel8.Schema.Spec as Kind ( Context )
35−import Rel8.Table ( Table, Congruent )
36−import Rel8.Type ( DBType )
37−
38−
39−type Recontextualize :: Kind.Context -> Kind.Context -> Type -> Type -> Constraint
40−class
41− ( Table from a
42− , Table to b
43− , Congruent a b
44− , Recontextualize from from a a
45− , Recontextualize to to b b
46− , Recontextualize to from b a
47− ) => Recontextualize from to a b
48− | a -> from
49− , b -> to
50− , a to -> b
51− , b from -> a
52−
53−
54−instance (DBType db, Nullabilizes db a) =>
55− Recontextualize Aggregation Aggregation (Aggregate (Expr a)) (Aggregate (Expr a))
56−
57−
58−instance (DBType db, Nullabilizes db a) =>
59− Recontextualize Aggregation DB (Aggregate (Expr a)) (Expr a)
60−
61−
62−instance (DBType db, Nullabilizes db a) =>
63− Recontextualize Aggregation Result (Aggregate (Expr a)) (Identity a)
64−
65−
66−instance (DBType db, Nullabilizes db a) =>
67− Recontextualize DB Aggregation (Expr a) (Aggregate (Expr a))
68−
69−
70−instance (DBType db, Nullabilizes db a) =>
71− Recontextualize DB DB (Expr a) (Expr a)
72−
73−
74−instance (DBType db, Nullabilizes db a) =>
75− Recontextualize DB Result (Expr a) (Identity a)
76−
77−
78−instance (DBType db, Nullabilizes db a) =>
79− Recontextualize Result Aggregation (Identity a) (Aggregate (Expr a))
80−
81−
82−instance (DBType db, Nullabilizes db a) =>
83− Recontextualize Result DB (Identity a) (Expr a)
84−
85−
86−instance (DBType db, Nullabilizes db a) =>
87− Recontextualize Result Result (Identity a) (Identity a)
88−
89−
90−instance KnownSpec spec => Recontextualize from to (from spec) (to spec)
91−
92−
93−instance Recontextualize from to (Opaque1 from a) (Opaque1 to a)
94−
95−
96−instance HTable t => Recontextualize from to (t (H from)) (t (H to))
97−
98−
99−instance
100− ( Table from (t from)
101− , Table to (t to)
102− , Congruent (t from) (t to)
103− ) => Recontextualize from to (t from) (t to)
104−
105−
106−instance
107− ( Recontextualize from to a1 b1
108− , Recontextualize from to a2 b2
109− , Labelable from
110− , Labelable to
111− ) => Recontextualize from to (a1, a2) (b1, b2)
112−
113−
114−instance
115− ( Recontextualize from to a1 b1
116− , Recontextualize from to a2 b2
117− , Recontextualize from to a3 b3
118− , Labelable from, Labelable to
119− ) => Recontextualize from to (a1, a2, a3) (b1, b2, b3)
120−
121−
122−instance
123− ( Recontextualize from to a1 b1
124− , Recontextualize from to a2 b2
125− , Recontextualize from to a3 b3
126− , Recontextualize from to a4 b4
127− , Labelable from, Labelable to
128− ) => Recontextualize from to (a1, a2, a3, a4) (b1, b2, b3, b4)
129−
130−
131−instance
132− ( Recontextualize from to a1 b1
133− , Recontextualize from to a2 b2
134− , Recontextualize from to a3 b3
135− , Recontextualize from to a4 b4
136− , Recontextualize from to a5 b5
137− , Labelable from, Labelable to
138− ) => Recontextualize from to (a1, a2, a3, a4, a5) (b1, b2, b3, b4, b5)
139−
140−
141−type Aggregates :: Type -> Type -> Constraint
142−class Recontextualize Aggregation DB aggregates exprs => Aggregates aggregates exprs
143−instance Recontextualize Aggregation DB aggregates exprs => Aggregates aggregates exprs
144−instance {-# OVERLAPPING #-} Aggregates (Opaque1 Aggregation Opaque) (Opaque1 DB Opaque)
145−
146−
147−type Encodes :: Type -> Type -> Constraint
148−class Recontextualize Result DB a exprs => Encodes a exprs
149−instance Recontextualize Result DB a exprs => Encodes a exprs
150−instance {-# OVERLAPPING #-} Encodes (Opaque1 Result Opaque) (Opaque1 DB Opaque)
151−
152−
153−type Inserts :: Type -> Type -> Constraint
154−class Recontextualize DB Insertion exprs inserts => Inserts exprs inserts
155−instance Recontextualize DB Insertion exprs inserts => Inserts exprs inserts
156−instance {-# OVERLAPPING #-} Inserts (Opaque1 DB Opaque) (Opaque1 Insertion Opaque)
157−
158−
159−type Selects :: Type -> Type -> Constraint
160−class Recontextualize Name DB names exprs => Selects names exprs
161−instance Recontextualize Name DB names exprs => Selects names exprs
162−instance {-# OVERLAPPING #-} Selects (Opaque1 Name Opaque) (Opaque1 DB Opaque)
src/Rel8/Table/Rel8able.hsnew file+92
@@ -0,0 +1,92 @@
1+{-# language DataKinds #-}
2+{-# language FlexibleInstances #-}
3+{-# language MultiParamTypeClasses #-}
4+{-# language ScopedTypeVariables #-}
5+{-# language StandaloneKindSignatures #-}
6+{-# language TypeApplications #-}
7+{-# language TypeFamilies #-}
8+{-# language UndecidableInstances #-}
9+
10+{-# options_ghc -fno-warn-orphans #-}
11+
12+module Rel8.Table.Rel8able
13+ (
14+ )
15+where
16+
17+-- base
18+import Prelude ()
19+
20+-- rel8
21+import Rel8.Expr ( Expr )
22+import qualified Rel8.Kind.Algebra as K
23+import Rel8.Kind.Context ( Reifiable, contextSing )
24+import Rel8.Generic.Rel8able
25+ ( Rel8able, Algebra
26+ , GColumns, gfromColumns, gtoColumns
27+ , GFromExprs, gfromResult, gtoResult
28+ )
29+import qualified Rel8.Schema.Kind as K
30+import Rel8.Schema.HTable ( HConstrainTable, hdicts )
31+import Rel8.Schema.Null ( Sql )
32+import Rel8.Schema.Result ( Result )
33+import Rel8.Table
34+ ( Table, Columns, Context, fromColumns, toColumns
35+ , FromExprs, fromResult, toResult
36+ , Transpose
37+ )
38+import Rel8.Table.ADT ( ADT )
39+import Rel8.Table.Eq ( EqTable, eqTable )
40+import Rel8.Table.Ord ( OrdTable, ordTable )
41+import Rel8.Table.Serialize ( ToExprs )
42+import Rel8.Type.Eq ( DBEq )
43+import Rel8.Type.Ord ( DBOrd )
44+
45+
46+instance (Rel8able t, Reifiable context, context ~ context') =>
47+ Table context' (t context)
48+ where
49+ type Columns (t context) = GColumns t
50+ type Context (t context) = context
51+ type FromExprs (t context) = GFromExprs t
52+ type Transpose to (t context) = t to
53+
54+ fromColumns = gfromColumns contextSing
55+ toColumns = gtoColumns contextSing
56+ fromResult = gfromResult @t
57+ toResult = gtoResult @t
58+
59+
60+instance
61+ ( context ~ Expr
62+ , Rel8able t
63+ , HConstrainTable (Columns (t context)) (Sql DBEq)
64+ )
65+ => EqTable (t context)
66+ where
67+ eqTable = hdicts @(Columns (t context)) @(Sql DBEq)
68+
69+
70+instance
71+ ( context ~ Expr
72+ , Rel8able t
73+ , HConstrainTable (Columns (t context)) (Sql DBEq)
74+ , HConstrainTable (Columns (t context)) (Sql DBOrd)
75+ )
76+ => OrdTable (t context)
77+ where
78+ ordTable = hdicts @(Columns (t context)) @(Sql DBOrd)
79+
80+
81+instance
82+ ( Rel8able t', t' ~ Choose (Algebra t) t
83+ , x ~ t' Expr
84+ , result ~ Result
85+ )
86+ => ToExprs x (t result)
87+
88+
89+type Choose :: K.Algebra -> K.Rel8able -> K.Rel8able
90+type family Choose algebra t where
91+ Choose 'K.Sum t = ADT t
92+ Choose 'K.Product t = t
src/Rel8/Table/Serialize.hs+72−374
@@ -1,6 +1,4 @@
11{-# language AllowAmbiguousTypes #-}
2−{-# language DataKinds #-}
3−{-# language DisambiguateRecordFields #-}
42{-# language FlexibleContexts #-}
53{-# language FlexibleInstances #-}
64{-# language FunctionalDependencies #-}
@@ -9,16 +7,16 @@
97{-# language StandaloneKindSignatures #-}
108{-# language TypeApplications #-}
119{-# language TypeFamilies #-}
12−{-# language ViewPatterns #-}
1310{-# language UndecidableInstances #-}
1411
1512module Rel8.Table.Serialize
16− ( Serializable, lit, parse
13+ ( Serializable, lit, litHTable, parse
14+ , ToExprs
1715 )
1816where
1917
2018-- base
21−import Data.Bifunctor ( bimap )
19+import Data.Functor.Identity ( Identity( Identity ) )
2220import Data.Kind ( Constraint, Type )
2321import Data.List.NonEmpty ( NonEmpty )
2422import Prelude
@@ -29,422 +27,122 @@ import qualified Hasql.Decoders as Hasql
2927-- rel8
3028import Rel8.Expr ( Expr )
3129import Rel8.Expr.Serialize ( slitExpr, sparseValue )
32−import Rel8.Opaque ( Opaque )
33−import Rel8.Schema.Context ( DB(..), Result(..) )
34−import Rel8.Schema.Context.Label ( labeler, unlabeler )
35−import Rel8.Schema.Context.Result
36− ( fromHEitherTable, toHEitherTable
37− , fromHListTable, toHListTable
38− , fromHMaybeTable, toHMaybeTable
39− , fromHNonEmptyTable, toHNonEmptyTable
40− , fromHTheseTable, toHTheseTable
41− )
4230import Rel8.Schema.HTable ( HTable, htabulate, htabulateA, hfield, hspecs )
43−import Rel8.Schema.HTable.Label ( hlabel, hunlabel )
44−import Rel8.Schema.HTable.Quartet ( HQuartet(..) )
45−import Rel8.Schema.HTable.Quintet ( HQuintet(..) )
46−import Rel8.Schema.HTable.Pair ( HPair(..) )
47−import Rel8.Schema.HTable.Trio ( HTrio(..) )
48−import Rel8.Schema.HTable.Type ( HType(..) )
49−import Rel8.Schema.HTable.Context ( H )
50−import Rel8.Schema.Nullability ( IsMaybe, Nullabilizes )
51−import Rel8.Schema.Spec ( SSpec(..), KnownSpec )
52−import Rel8.Table ( Table, Columns, fromColumns, toColumns )
53−import Rel8.Table.Either ( EitherTable )
54−import Rel8.Table.List ( ListTable )
55−import Rel8.Table.Maybe ( MaybeTable )
56−import Rel8.Table.NonEmpty ( NonEmptyTable )
57−import Rel8.Table.Recontextualize ( Encodes )
58−import Rel8.Table.These ( TheseTable )
31+import Rel8.Schema.Null ( NotNull, Sql )
32+import Rel8.Schema.Result ( Result )
33+import Rel8.Schema.Spec ( Spec(..) )
34+import Rel8.Table ( Table, fromColumns, FromExprs, fromResult, toResult )
5935import Rel8.Type ( DBType )
6036
6137-- semigroupoids
6238import Data.Functor.Apply ( WrappedApplicative(..) )
6339
64−-- these
65−import Data.These ( These )
66−
67−
68−type IsPlainColumn :: Type -> Bool
69−type family IsPlainColumn a where
70− IsPlainColumn (Either _ _) = 'False
71− IsPlainColumn [_] = 'False
72− IsPlainColumn (Maybe _) = 'False
73− IsPlainColumn (NonEmpty _) = 'False
74− IsPlainColumn (These _ _) = 'False
75− IsPlainColumn (_, _) = 'False
76− IsPlainColumn (_, _, _) = 'False
77− IsPlainColumn (_, _, _, _) = 'False
78− IsPlainColumn (_, _, _, _, _) = 'False
79− IsPlainColumn (_ (H Result)) = 'False
80− IsPlainColumn (_ Result) = 'False
81− IsPlainColumn (Result _) = 'False
82− IsPlainColumn _ = 'True
83−
84−
85−type IsTabular :: Type -> Bool
86−type family IsTabular a where
87− IsTabular (Either _ _) = 'True
88− IsTabular [a] = IsListTabular a
89− IsTabular (Maybe a) = IsMaybeTabular a
90− IsTabular (NonEmpty a) = IsListTabular a
91− IsTabular (These _ _) = 'True
92− IsTabular (_, _) = 'True
93− IsTabular (_, _, _) = 'True
94− IsTabular (_, _, _, _) = 'True
95− IsTabular (_, _, _, _, _) = 'True
96− IsTabular (_ (H Result)) = 'True
97− IsTabular (_ Result) = 'True
98− IsTabular (Result _) = 'True
99− IsTabular _ = 'False
100−
101−
102−type IsTabular' :: Bool -> Type -> Bool
103−type family IsTabular' isTabular exprs where
104− IsTabular' _ (Expr _) = 'False
105− IsTabular' 'False _ = 'False
106− IsTabular' _ _ = 'True
107−
108−
109−type IsMaybeTabular :: Type -> Bool
110−type family IsMaybeTabular a where
111− IsMaybeTabular (Maybe _) = 'True
112− IsMaybeTabular a = IsTabular a
113−
114−
115−type IsListTabular :: Type -> Bool
116−type family IsListTabular a where
117− IsListTabular (Maybe a) = IsMaybeTabular a
118− IsListTabular a = IsTabular a
119−
12040
41+-- | @ToExprs exprs a@ is evidence that the types @exprs@ and @a@ describe
42+-- essentially the same type, but @exprs@ is in the 'Expr' context, and @a@ is
43+-- a normal Haskell type.
12144type ToExprs :: Type -> Type -> Constraint
122−class ExprsFor (IsPlainColumn a) (IsTabular' (IsTabular a) exprs) a exprs => ToExprs a exprs
123−instance ExprsFor (IsPlainColumn a) (IsTabular' (IsTabular a) exprs) a exprs => ToExprs a exprs
124−
125−
126−fromResults' :: forall exprs a. ToExprs a exprs => Columns exprs (H Result) -> a
127−fromResults' = fromResults @(IsPlainColumn a) @_ @_ @exprs
128−
129−
130−toResults' :: forall exprs a. ToExprs a exprs => a -> Columns exprs (H Result)
131−toResults' = toResults @(IsPlainColumn a) @_ @_ @exprs
132−
133−
134−type ExprsFor :: Bool -> Bool -> Type -> Type -> Constraint
135−class (Table DB exprs, isTabular ~ IsTabular a) =>
136− ExprsFor isPlainColumn isTabular a exprs where
137− fromResults :: Columns exprs (H Result) -> a
138− toResults :: a -> Columns exprs (H Result)
139−
140−
141−instance
142− ( DBType a
143− , IsMaybe a ~ 'False
144− , IsTabular a ~ 'False
145− , x ~ Expr a
146− )
147− => ExprsFor 'True 'False a x
148− where
149− fromResults (HType (Result a)) = a
150− toResults = HType . Result
151−
152−
153−instance
154− ( DBType db
155− , Nullabilizes db a
156− , IsListTabular a ~ 'False
157− , x ~ [a]
158− ) => ExprsFor 'False 'False [a] (Expr x)
159− where
160− fromResults (HType (Result a)) = a
161− toResults = HType . Result
162−
163−
164−instance
165− ( DBType a
166− , Nullabilizes a (Maybe a)
167− , isTabular ~ 'False
168− , IsMaybeTabular a ~ 'False
169− , x ~ Maybe a
170− ) => ExprsFor 'False 'False (Maybe a) (Expr x)
171− where
172− fromResults (HType (Result a)) = a
173− toResults = HType . Result
174−
175−
176−instance
177− ( DBType db
178− , Nullabilizes db a
179− , IsListTabular a ~ 'False
180− , x ~ NonEmpty a
181− ) => ExprsFor 'False 'False (NonEmpty a) (Expr x)
182− where
183− fromResults (HType (Result a)) = a
184− toResults = HType . Result
185−
186−
187−instance
188− ( ToExprs a exprs
189− , IsListTabular a ~ 'False
190− ) => ExprsFor 'False 'False [a] (ListTable exprs)
191− where
192− fromResults = fmap (fromResults' @exprs) . fromHListTable
193− toResults = toHListTable . fmap (toResults' @exprs)
194−
195−
196−instance
197− ( ToExprs a exprs
198− , IsMaybeTabular a ~ 'False
199− ) => ExprsFor 'False 'False (Maybe a) (MaybeTable exprs)
200− where
201− fromResults =
202− fmap (fromResults' @exprs . hunlabel unlabeler) .
203− fromHMaybeTable
204− toResults =
205− toHMaybeTable .
206− fmap (hlabel labeler . toResults' @exprs)
207−
208−
209−instance
210− ( ToExprs a exprs
211− , IsListTabular a ~ 'False
212− ) => ExprsFor 'False 'False (NonEmpty a) (NonEmptyTable exprs)
213− where
214− fromResults = fmap (fromResults' @exprs) . fromHNonEmptyTable
215− toResults = toHNonEmptyTable . fmap (toResults' @exprs)
216−
217−
218−instance
219− ( ToExprs a exprs1
220− , ToExprs b exprs2
221− , isTabular ~ 'True
222− , x ~ EitherTable exprs1 exprs2
223− ) => ExprsFor 'False isTabular (Either a b) x
224− where
225− fromResults =
226− bimap
227− (fromResults' @exprs1 . hunlabel unlabeler)
228− (fromResults' @exprs2 . hunlabel unlabeler) .
229− fromHEitherTable
230− toResults =
231− toHEitherTable .
232− bimap
233− (hlabel labeler . toResults' @exprs1)
234− (hlabel labeler . toResults' @exprs2)
45+class Table Expr exprs => ToExprs exprs a
23546
23647
237−instance
238− ( ToExprs a exprs
239− , IsListTabular a ~ 'True
240− , x ~ ListTable exprs
241− ) => ExprsFor 'False 'True [a] x
242− where
243− fromResults = fmap (fromResults' @exprs) . fromHListTable
244− toResults = toHListTable . fmap (toResults' @exprs)
48+instance {-# OVERLAPPABLE #-} (Sql DBType a, x ~ Expr a) => ToExprs x a
24549
24650
247−instance
248− ( ToExprs a exprs
249− , IsMaybeTabular a ~ 'True
250− , x ~ MaybeTable exprs
251− ) => ExprsFor 'False 'True (Maybe a) x
252− where
253− fromResults =
254− fmap (fromResults' @exprs . hunlabel unlabeler) .
255− fromHMaybeTable
256− toResults =
257− toHMaybeTable .
258− fmap (hlabel labeler . toResults' @exprs)
51+instance (Sql DBType a, x ~ [a]) => ToExprs (Expr x) [a]
25952
26053
261−instance
262− ( ToExprs a exprs
263− , IsListTabular a ~ 'True
264− , x ~ NonEmptyTable exprs
265− ) => ExprsFor 'False 'True (NonEmpty a) x
266− where
267− fromResults = fmap (fromResults' @exprs) . fromHNonEmptyTable
268− toResults = toHNonEmptyTable . fmap (toResults' @exprs)
54+instance (Sql DBType a, NotNull a, x ~ Maybe a) => ToExprs (Expr x) (Maybe a)
26955
27056
271−instance
272− ( ToExprs a exprs1
273− , ToExprs b exprs2
274− , isTabular ~ 'True
275− , x ~ TheseTable exprs1 exprs2
276− ) => ExprsFor 'False isTabular (These a b) x
277− where
278− fromResults =
279− bimap
280− (fromResults' @exprs1 . hunlabel unlabeler)
281− (fromResults' @exprs2 . hunlabel unlabeler) .
282− fromHTheseTable
283− toResults =
284− toHTheseTable .
285− bimap
286− (hlabel labeler . toResults' @exprs1)
287− (hlabel labeler . toResults' @exprs2)
57+instance (Sql DBType a, NotNull a, x ~ NonEmpty a) => ToExprs (Expr x) (NonEmpty a)
28858
28959
290−instance
291− ( ToExprs a exprs1
292− , ToExprs b exprs2
293− , isTabular ~ 'True
294− , x ~ (exprs1, exprs2)
295− ) => ExprsFor 'False isTabular (a, b) x
296− where
297− fromResults (HPair a b) =
298− ( fromResults' @exprs1 $ hunlabel unlabeler a
299− , fromResults' @exprs2 $ hunlabel unlabeler b
300− )
301− toResults (a, b) = HPair
302− { hfst = hlabel labeler $ toResults' @exprs1 a
303− , hsnd = hlabel labeler $ toResults' @exprs2 b
304− }
60+instance (ToExprs exprs1 a, ToExprs exprs2 b, x ~ (exprs1, exprs2)) =>
61+ ToExprs x (a, b)
30562
30663
30764instance
308− ( ToExprs a exprs1
309− , ToExprs b exprs2
310− , ToExprs c exprs3
311− , isTabular ~ 'True
65+ ( ToExprs exprs1 a
66+ , ToExprs exprs2 b
67+ , ToExprs exprs3 c
31268 , x ~ (exprs1, exprs2, exprs3)
313− ) => ExprsFor 'False isTabular (a, b, c) x
314− where
315− fromResults (HTrio a b c) =
316− ( fromResults' @exprs1 $ hunlabel unlabeler a
317− , fromResults' @exprs2 $ hunlabel unlabeler b
318− , fromResults' @exprs3 $ hunlabel unlabeler c
319− )
320− toResults (a, b, c) = HTrio
321− { hfst = hlabel labeler $ toResults' @exprs1 a
322− , hsnd = hlabel labeler $ toResults' @exprs2 b
323− , htrd = hlabel labeler $ toResults' @exprs3 c
324− }
69+ )
70+ => ToExprs x (a, b, c)
32571
32672
32773instance
328− ( ToExprs a exprs1
329− , ToExprs b exprs2
330− , ToExprs c exprs3
331− , ToExprs d exprs4
332− , isTabular ~ 'True
74+ ( ToExprs exprs1 a
75+ , ToExprs exprs2 b
76+ , ToExprs exprs3 c
77+ , ToExprs exprs4 d
33378 , x ~ (exprs1, exprs2, exprs3, exprs4)
334− ) => ExprsFor 'False isTabular (a, b, c, d) x
335− where
336− fromResults (HQuartet a b c d) =
337− ( fromResults' @exprs1 $ hunlabel unlabeler a
338− , fromResults' @exprs2 $ hunlabel unlabeler b
339− , fromResults' @exprs3 $ hunlabel unlabeler c
340− , fromResults' @exprs4 $ hunlabel unlabeler d
341− )
342− toResults (a, b, c, d) = HQuartet
343− { hfst = hlabel labeler $ toResults' @exprs1 a
344− , hsnd = hlabel labeler $ toResults' @exprs2 b
345− , htrd = hlabel labeler $ toResults' @exprs3 c
346− , hfrt = hlabel labeler $ toResults' @exprs4 d
347− }
79+ )
80+ => ToExprs x (a, b, c, d)
34881
34982
35083instance
351− ( ToExprs a exprs1
352− , ToExprs b exprs2
353− , ToExprs c exprs3
354− , ToExprs d exprs4
355− , ToExprs e exprs5
356− , isTabular ~ 'True
84+ ( ToExprs exprs1 a
85+ , ToExprs exprs2 b
86+ , ToExprs exprs3 c
87+ , ToExprs exprs4 d
88+ , ToExprs exprs5 e
35789 , x ~ (exprs1, exprs2, exprs3, exprs4, exprs5)
358− ) => ExprsFor 'False isTabular (a, b, c, d, e) x
359− where
360− fromResults (HQuintet a b c d e) =
361− ( fromResults' @exprs1 $ hunlabel unlabeler a
362− , fromResults' @exprs2 $ hunlabel unlabeler b
363− , fromResults' @exprs3 $ hunlabel unlabeler c
364− , fromResults' @exprs4 $ hunlabel unlabeler d
365− , fromResults' @exprs5 $ hunlabel unlabeler e
366− )
367− toResults (a, b, c, d, e) = HQuintet
368− { hfst = hlabel labeler $ toResults' @exprs1 a
369− , hsnd = hlabel labeler $ toResults' @exprs2 b
370− , htrd = hlabel labeler $ toResults' @exprs3 c
371− , hfrt = hlabel labeler $ toResults' @exprs4 d
372− , hfft = hlabel labeler $ toResults' @exprs5 e
373− }
90+ )
91+ => ToExprs x (a, b, c, d, e)
37492
37593
37694instance
377− ( HTable t
378− , isTabular ~ 'True
379− , result ~ H Result
380− , x ~ t (H DB)
381− ) => ExprsFor 'False isTabular (t result) x
382− where
383− fromResults = id
384− toResults = id
95+ ( ToExprs exprs1 a
96+ , ToExprs exprs2 b
97+ , ToExprs exprs3 c
98+ , ToExprs exprs4 d
99+ , ToExprs exprs5 e
100+ , ToExprs exprs6 f
101+ , x ~ (exprs1, exprs2, exprs3, exprs4, exprs5, exprs6)
102+ )
103+ => ToExprs x (a, b, c, d, e, f)
385104
386105
387106instance
388− ( Encodes (t Result) (t DB)
389− , isTabular ~ 'True
390− , result ~ Result
391− , x ~ t DB
392− ) => ExprsFor 'False isTabular (t result) x
393− where
394− fromResults = fromColumns
395− toResults = toColumns
107+ ( ToExprs exprs1 a
108+ , ToExprs exprs2 b
109+ , ToExprs exprs3 c
110+ , ToExprs exprs4 d
111+ , ToExprs exprs5 e
112+ , ToExprs exprs6 f
113+ , ToExprs exprs7 g
114+ , x ~ (exprs1, exprs2, exprs3, exprs4, exprs5, exprs6, exprs7)
115+ )
116+ => ToExprs x (a, b, c, d, e, f, g)
396117
397118
398−instance
399− ( KnownSpec spec
400− , isTabular ~ 'True
401− , x ~ DB spec
402− ) => ExprsFor 'False isTabular (Result spec) x
403− where
404− fromResults = fromColumns
405− toResults = toColumns
406−
407−
408−type FromExprs :: Type -> Type
409−type family FromExprs a where
410− FromExprs (Expr a) = a
411− FromExprs (DB spec) = Result spec
412− FromExprs (EitherTable a b) = Either (FromExprs a) (FromExprs b)
413− FromExprs (ListTable a) = [FromExprs a]
414− FromExprs (MaybeTable a) = Maybe (FromExprs a)
415− FromExprs (NonEmptyTable a) = NonEmpty (FromExprs a)
416− FromExprs (TheseTable a b) = These (FromExprs a) (FromExprs b)
417− FromExprs (a, b) = (FromExprs a, FromExprs b)
418− FromExprs (a, b, c) = (FromExprs a, FromExprs b, FromExprs c)
419− FromExprs (a, b, c, d) =
420− (FromExprs a, FromExprs b, FromExprs c, FromExprs d)
421− FromExprs (a, b, c, d, e) =
422− (FromExprs a, FromExprs b, FromExprs c, FromExprs d, FromExprs e)
423− FromExprs (t DB) = t Result
424− FromExprs (t (H DB)) = t (H Result)
425−
426−
427−class (ToExprs a exprs, a ~ FromExprs exprs) => Serializable exprs a | exprs -> a
428−instance (ToExprs a exprs, a ~ FromExprs exprs) => Serializable exprs a
429−instance Serializable (Expr Opaque) Opaque
119+-- | @Serializable@ witnesses the one-to-one correspondence between the type
120+-- @sql@, which contains SQL expressions, and the type @haskell@, which
121+-- contains the Haskell decoding of rows containing @sql@ SQL expressions.
122+type Serializable :: Type -> Type -> Constraint
123+class (ToExprs exprs a, a ~ FromExprs exprs) => Serializable exprs a | exprs -> a
124+instance (ToExprs exprs a, a ~ FromExprs exprs) => Serializable exprs a
125+instance {-# OVERLAPPING #-} Sql DBType a => Serializable (Expr a) a
430126
431127
128+-- | Use @lit@ to turn literal Haskell values into expressions. @lit@ is
129+-- capable of lifting single @Expr@s to full tables.
432130lit :: forall exprs a. Serializable exprs a => a -> exprs
433−lit = fromColumns . litTable . toResults' @exprs
131+lit = fromColumns . litHTable . toResult @_ @exprs
434132
435133
436134parse :: forall exprs a. Serializable exprs a => Hasql.Row a
437−parse = fromResults' @exprs <$> parseTable
135+parse = fromResult @_ @exprs <$> parseHTable
438136
439137
440−litTable :: Encodes a b => a -> b
441−litTable (toColumns -> as) = fromColumns $ htabulate $ \field ->
138+litHTable :: HTable t => t Result -> t Expr
139+litHTable as = htabulate $ \field ->
442140 case hfield hspecs field of
443− SSpec {nullability, info} -> case hfield as field of
444− Result value -> DB (slitExpr nullability info value)
141+ Spec {nullity, info} -> case hfield as field of
142+ Identity value -> slitExpr nullity info value
445143
446144
447−parseTable :: Table Result a => Hasql.Row a
448−parseTable = fmap fromColumns $ unwrapApplicative $ htabulateA $ \field ->
145+parseHTable :: HTable t => Hasql.Row (t Result)
146+parseHTable = unwrapApplicative $ htabulateA $ \field ->
449147 WrapApplicative $ case hfield hspecs field of
450− SSpec {nullability, info} -> Result <$> sparseValue nullability info
148+ Spec {nullity, info} -> Identity <$> sparseValue nullity info
src/Rel8/Table/These.hs+234−110
@@ -5,85 +5,122 @@
55{-# language FlexibleInstances #-}
66{-# language MultiParamTypeClasses #-}
77{-# language NamedFieldPuns #-}
8+{-# language ScopedTypeVariables #-}
89{-# language StandaloneKindSignatures #-}
910{-# language TupleSections #-}
11+{-# language TypeApplications #-}
1012{-# language TypeFamilies #-}
1113{-# language UndecidableInstances #-}
1214
15+{-# options_ghc -fno-warn-orphans #-}
16+
1317module Rel8.Table.These
1418 ( TheseTable(..)
1519 , theseTable, thisTable, thatTable, thoseTable
1620 , isThisTable, isThatTable, isThoseTable
1721 , hasHereTable, hasThereTable
1822 , justHereTable, justThereTable
23+ , alignMaybeTable
24+ , aggregateTheseTable
25+ , nameTheseTable
1926 )
2027where
2128
2229-- base
2330import Data.Bifunctor ( Bifunctor, bimap )
24−import Data.Functor.Identity ( runIdentity )
2531import Data.Kind ( Type )
26−import Prelude hiding ( undefined )
32+import Data.Maybe ( isJust )
33+import Prelude hiding ( null, undefined )
2734
2835-- rel8
36+import Rel8.Aggregate ( Aggregate )
2937import Rel8.Expr ( Expr )
30−import Rel8.Expr.Bool ( (&&.), not_ )
31−import Rel8.Expr.Null ( isNonNull )
32−import Rel8.Schema.Context ( DB )
33−import Rel8.Schema.Context.Label ( Labelable, labeler, unlabeler )
34−import Rel8.Schema.Context.Nullify
35− ( Nullifiable, NullifiableEq
36− , encodeTag, decodeTag
37− , nullifier, unnullifier
38− )
39−import Rel8.Schema.HTable.Label ( HLabel, hlabel, hunlabel )
38+import Rel8.Expr.Bool ( (&&.), (||.), boolExpr, not_ )
39+import Rel8.Expr.Null ( null, isNonNull )
40+import Rel8.Kind.Context ( Reifiable )
41+import Rel8.Schema.Context.Nullify ( Nullifiable )
42+import Rel8.Schema.Dict ( Dict( Dict ) )
43+import Rel8.Schema.HTable.Label ( hlabel, hrelabel, hunlabel )
4044import Rel8.Schema.HTable.Identity ( HIdentity(..) )
41−import Rel8.Schema.HTable.Nullify ( hnullify, hunnullify )
45+import Rel8.Schema.HTable.Maybe ( HMaybeTable(..) )
4246import Rel8.Schema.HTable.These ( HTheseTable(..) )
43−import Rel8.Table ( Table, Columns, Context, fromColumns, toColumns )
44−import Rel8.Table.Lifted
45− ( Table1, Columns1, ConstrainContext1, fromColumns1, toColumns1
46− , Table2, Columns2, ConstrainContext2, fromColumns2, toColumns2
47+import qualified Rel8.Schema.Kind as K
48+import Rel8.Schema.Name ( Name )
49+import Rel8.Table
50+ ( Table, Columns, Context, fromColumns, toColumns
51+ , FromExprs, fromResult, toResult
52+ , Transpose
4753 )
54+import Rel8.Table.Eq ( EqTable, eqTable )
4855import Rel8.Table.Maybe
4956 ( MaybeTable(..)
5057 , maybeTable, justTable, nothingTable
5158 , isJustTable
59+ , aggregateMaybeTable
60+ , nameMaybeTable
5261 )
53−import Rel8.Table.Recontextualize ( Recontextualize )
62+import Rel8.Table.Nullify ( Nullify, guard )
63+import Rel8.Table.Ord ( OrdTable, ordTable )
64+import Rel8.Table.Projection ( Biprojectable, Projectable, biproject, project )
65+import Rel8.Table.Serialize ( ToExprs )
5466import Rel8.Table.Undefined ( undefined )
67+import Rel8.Type.Tag ( MaybeTag )
5568
5669-- semigroupoids
5770import Data.Functor.Apply ( Apply, (<.>) )
5871import Data.Functor.Bind ( Bind, (>>-) )
5972
60−
61−type TheseTable :: Type -> Type -> Type
62−data TheseTable a b = TheseTable
63− { here :: MaybeTable a
64− , there :: MaybeTable b
73+-- these
74+import Data.These ( These( This, That, These ) )
75+import Data.These.Combinators ( justHere, justThere )
76+
77+
78+-- | @TheseTable a b@ is a Rel8 table that contains either the table @a@, the
79+-- table @b@, or both tables @a@ and @b@. You can construct @TheseTable@s using
80+-- 'thisTable', 'thatTable' and 'thoseTable'. @TheseTable@s can be
81+-- eliminated/pattern matched using 'theseTable'.
82+--
83+-- @TheseTable@ is operationally the same as Haskell's 'These' type, but
84+-- adapted to work with Rel8.
85+type TheseTable :: K.Context -> Type -> Type -> Type
86+data TheseTable context a b = TheseTable
87+ { here :: MaybeTable context a
88+ , there :: MaybeTable context b
6589 }
66− deriving stock (Show, Functor)
90+ deriving stock Functor
91+
92+
93+instance Biprojectable (TheseTable context) where
94+ biproject f g (TheseTable a b) = TheseTable (project f a) (project g b)
6795
6896
69−instance Bifunctor TheseTable where
97+instance Nullifiable context => Bifunctor (TheseTable context) where
7098 bimap f g (TheseTable a b) = TheseTable (fmap f a) (fmap g b)
7199
72100
73−instance (Table DB a, Semigroup a) => Apply (TheseTable a) where
101+instance Projectable (TheseTable context a) where
102+ project f (TheseTable a b) = TheseTable a (project f b)
103+
104+
105+instance (context ~ Expr, Table Expr a, Semigroup a) =>
106+ Apply (TheseTable context a)
107+ where
74108 fs <.> as = TheseTable
75109 { here = here fs <> here as
76110 , there = there fs <.> there as
77111 }
78112
79113
80−instance (Table DB a, Semigroup a) => Applicative (TheseTable a)
114+instance (context ~ Expr, Table Expr a, Semigroup a) =>
115+ Applicative (TheseTable context a)
81116 where
82117 pure = thatTable
83118 (<*>) = (<.>)
84119
85120
86−instance (Table DB a, Semigroup a) => Bind (TheseTable a) where
121+instance (context ~ Expr, Table Expr a, Semigroup a) =>
122+ Bind (TheseTable context a)
123+ where
87124 TheseTable here1 ma >>- f = case ma >>- f' of
88125 mtb -> TheseTable
89126 { here = maybeTable here1 ((here1 <>) . fst) mtb
@@ -94,12 +131,14 @@ instance (Table DB a, Semigroup a) => Bind (TheseTable a) where
94131 TheseTable here2 mb -> (here2,) <$> mb
95132
96133
97−instance (Table DB a, Semigroup a) => Monad (TheseTable a) where
134+instance (context ~ Expr, Table Expr a, Semigroup a) =>
135+ Monad (TheseTable context a)
136+ where
98137 (>>=) = (>>-)
99138
100139
101−instance (Table DB a, Table DB b, Semigroup a, Semigroup b) =>
102− Semigroup (TheseTable a b)
140+instance (context ~ Expr, Table Expr a, Table Expr b, Semigroup a, Semigroup b) =>
141+ Semigroup (TheseTable context a b)
103142 where
104143 a <> b = TheseTable
105144 { here = here a <> here b
@@ -107,127 +146,212 @@ instance (Table DB a, Table DB b, Semigroup a, Semigroup b) =>
107146 }
108147
109148
110−instance Table2 TheseTable where
111− type Columns2 TheseTable = HTheseTable
112− type ConstrainContext2 TheseTable = Nullifiable
113−
114− toColumns2 f g TheseTable {here, there} = HTheseTable
115− { hhereTag = HIdentity $ encodeTag (tag here)
116− , hhere = hnullify (nullifier (isNonNull (tag here))) $ f (just here)
117− , hthereTag = HIdentity $ encodeTag (tag there)
118− , hthere = hnullify (nullifier (isNonNull (tag there))) $ g (just there)
149+instance
150+ ( Table context a, Table context b
151+ , Reifiable context, context ~ context'
152+ )
153+ => Table context' (TheseTable context a b)
154+ where
155+ type Columns (TheseTable context a b) = HTheseTable (Columns a) (Columns b)
156+ type Context (TheseTable context a b) = Context a
157+ type FromExprs (TheseTable context a b) =
158+ These (FromExprs a) (FromExprs b)
159+ type Transpose to (TheseTable context a b) =
160+ TheseTable to (Transpose to a) (Transpose to b)
161+
162+ toColumns TheseTable {here, there} = HTheseTable
163+ { hhereTag = hlabel $ HIdentity $ tag here
164+ , hhere =
165+ hlabel $ guard (tag here) isJust isNonNull $ toColumns $ just here
166+ , hthereTag = hlabel $ HIdentity $ tag there
167+ , hthere =
168+ hlabel $ guard (tag there) isJust isNonNull $ toColumns $ just there
119169 }
120170
121− fromColumns2 f g HTheseTable {hhereTag, hhere, hthereTag, hthere} =
122− TheseTable
123− { here =
124− let
125− tag = decodeTag $ unHIdentity hhereTag
126− in
127− MaybeTable
128− { tag
129− , just = f $
130− runIdentity $
131− hunnullify (\a -> pure . unnullifier (isNonNull tag) a)
132− hhere
133− }
134− , there =
135− let
136− tag = decodeTag $ unHIdentity hthereTag
137− in
138− MaybeTable
139− { tag
140− , just = g $
141− runIdentity $
142− hunnullify (\a -> pure . unnullifier (isNonNull tag) a)
143− hthere
144− }
145− }
146−
147− {-# INLINABLE fromColumns2 #-}
148− {-# INLINABLE toColumns2 #-}
149−
150−
151−instance Table context a => Table1 (TheseTable a) where
152− type Columns1 (TheseTable a) = HTheseTable (Columns a)
153− type ConstrainContext1 (TheseTable a) = NullifiableEq (Context a)
171+ fromColumns HTheseTable {hhereTag, hhere, hthereTag, hthere} = TheseTable
172+ { here = MaybeTable
173+ { tag = unHIdentity $ hunlabel hhereTag
174+ , just = fromColumns $ hunlabel hhere
175+ }
176+ , there = MaybeTable
177+ { tag = unHIdentity $ hunlabel hthereTag
178+ , just = fromColumns $ hunlabel hthere
179+ }
180+ }
154181
155− toColumns1 = toColumns2 toColumns
156− fromColumns1 = fromColumns2 fromColumns
182+ toResult tables = HTheseTable
183+ { hhereTag = hrelabel hhereTag
184+ , hhere = hrelabel hhere
185+ , hthereTag = hrelabel hthereTag
186+ , hthere = hrelabel hthere
187+ }
188+ where
189+ HMaybeTable
190+ { htag = hhereTag
191+ , hjust = hhere
192+ } = toResult @_ @(MaybeTable context a) (justHere tables)
193+ HMaybeTable
194+ { htag = hthereTag
195+ , hjust = hthere
196+ } = toResult @_ @(MaybeTable context b) (justThere tables)
197+
198+ fromResult HTheseTable {hhereTag, hhere, hthereTag, hthere} =
199+ case (here, there) of
200+ (Just a, Nothing) -> This a
201+ (Nothing, Just b) -> That b
202+ (Just a, Just b) -> These a b
203+ _ -> error "These.fromColumns: mismatch between tags and data"
204+ where
205+ here = fromResult @_ @(MaybeTable context a) mhere
206+ there = fromResult @_ @(MaybeTable context b) mthere
207+ mhere = HMaybeTable
208+ { htag = hrelabel hhereTag
209+ , hjust = hrelabel hhere
210+ }
211+ mthere = HMaybeTable
212+ { htag = hrelabel hthereTag
213+ , hjust = hrelabel hthere
214+ }
215+
216+
217+instance (EqTable a, EqTable b, context ~ Expr) =>
218+ EqTable (TheseTable context a b)
219+ where
220+ eqTable = HTheseTable
221+ { hhereTag = hlabel (HIdentity Dict)
222+ , hhere = hlabel (eqTable @(Nullify context a))
223+ , hthereTag = hlabel (HIdentity Dict)
224+ , hthere = hlabel (eqTable @(Nullify context b))
225+ }
157226
158227
159−instance
160− ( Table context a, Table context b
161− , Labelable context, Nullifiable context
162− ) => Table context (TheseTable a b)
228+instance (OrdTable a, OrdTable b, context ~ Expr) =>
229+ OrdTable (TheseTable context a b)
163230 where
164− type Columns (TheseTable a b) =
165− HTheseTable (HLabel "Here" (Columns a)) (HLabel "There" (Columns b))
166− type Context (TheseTable a b) = Context a
231+ ordTable = HTheseTable
232+ { hhereTag = hlabel (HIdentity Dict)
233+ , hhere = hlabel (ordTable @(Nullify context a))
234+ , hthereTag = hlabel (HIdentity Dict)
235+ , hthere = hlabel (ordTable @(Nullify context b))
236+ }
167237
168− toColumns =
169− toColumns2
170− (hlabel labeler . toColumns)
171− (hlabel labeler . toColumns)
172− fromColumns =
173− fromColumns2
174− (fromColumns . hunlabel unlabeler)
175− (fromColumns . hunlabel unlabeler)
176238
239+instance (ToExprs exprs1 a, ToExprs exprs2 b, x ~ TheseTable Expr exprs1 exprs2) =>
240+ ToExprs x (These a b)
177241
178−instance
179− ( Labelable from, Nullifiable from
180− , Labelable to, Nullifiable to
181− , Recontextualize from to a1 b1
182− , Recontextualize from to a2 b2
183− ) =>
184− Recontextualize from to (TheseTable a1 a2) (TheseTable b1 b2)
185242
186−
187−isThisTable :: TheseTable a b -> Expr Bool
243+-- | Test if a 'TheseTable' was constructed with 'thisTable'.
244+--
245+-- Corresponds to 'Data.These.Combinators.isThis'.
246+isThisTable :: TheseTable Expr a b -> Expr Bool
188247isThisTable a = hasHereTable a &&. not_ (hasThereTable a)
189248
190249
191−isThatTable :: TheseTable a b -> Expr Bool
250+-- | Test if a 'TheseTable' was constructed with 'thatTable'.
251+--
252+-- Corresponds to 'Data.These.Combinators.isThat'.
253+isThatTable :: TheseTable Expr a b -> Expr Bool
192254isThatTable a = not_ (hasHereTable a) &&. hasThereTable a
193255
194256
195−isThoseTable :: TheseTable a b -> Expr Bool
257+-- | Test if a 'TheseTable' was constructed with 'thoseTable'.
258+--
259+-- Corresponds to 'Data.These.Combinators.isThese'.
260+isThoseTable :: TheseTable Expr a b -> Expr Bool
196261isThoseTable a = hasHereTable a &&. hasThereTable a
197262
198263
199−hasHereTable :: TheseTable a b -> Expr Bool
264+-- | Test if the @a@ side of @TheseTable a b@ is present.
265+--
266+-- Corresponds to 'Data.These.Combinators.hasHere'.
267+hasHereTable :: TheseTable Expr a b -> Expr Bool
200268hasHereTable TheseTable {here} = isJustTable here
201269
202270
203−hasThereTable :: TheseTable a b -> Expr Bool
271+-- | Test if the @b@ table of @TheseTable a b@ is present.
272+--
273+-- Corresponds to 'Data.These.Combinators.hasThere'.
274+hasThereTable :: TheseTable Expr a b -> Expr Bool
204275hasThereTable TheseTable {there} = isJustTable there
205276
206277
207−justHereTable :: TheseTable a b -> MaybeTable a
278+-- | Attempt to project out the @a@ table of a @TheseTable a b@.
279+--
280+-- Corresponds to 'Data.These.Combinators.justHere'.
281+justHereTable :: TheseTable context a b -> MaybeTable context a
208282justHereTable = here
209283
210284
211−justThereTable :: TheseTable a b -> MaybeTable b
285+-- | Attempt to project out the @b@ table of a @TheseTable a b@.
286+--
287+-- Corresponds to 'Data.These.Combinators.justThere'.
288+justThereTable :: TheseTable context a b -> MaybeTable context b
212289justThereTable = there
213290
214291
215−thisTable :: Table DB b => a -> TheseTable a b
292+-- | Construct a @TheseTable@ from two 'MaybeTable's.
293+alignMaybeTable :: ()
294+ => MaybeTable Expr a
295+ -> MaybeTable Expr b
296+ -> MaybeTable Expr (TheseTable Expr a b)
297+alignMaybeTable a b = MaybeTable tag (pure (TheseTable a b))
298+ where
299+ tag = boolExpr null mempty (isJustTable a ||. isJustTable b)
300+
301+
302+-- | Construct a @TheseTable@. Corresponds to 'This'.
303+thisTable :: Table Expr b => a -> TheseTable Expr a b
216304thisTable a = TheseTable (justTable a) nothingTable
217305
218306
219−thatTable :: Table DB a => b -> TheseTable a b
307+-- | Construct a @TheseTable@. Corresponds to 'That'.
308+thatTable :: Table Expr a => b -> TheseTable Expr a b
220309thatTable b = TheseTable nothingTable (justTable b)
221310
222311
223−thoseTable :: a -> b -> TheseTable a b
312+-- | Construct a @TheseTable@. Corresponds to 'These'.
313+thoseTable :: a -> b -> TheseTable Expr a b
224314thoseTable a b = TheseTable (justTable a) (justTable b)
225315
226316
227−theseTable :: Table DB c
228− => (a -> c) -> (b -> c) -> (a -> b -> c) -> TheseTable a b -> c
317+-- | Pattern match on a 'TheseTable'. Corresponds to 'these'.
318+theseTable :: Table Expr c
319+ => (a -> c) -> (b -> c) -> (a -> b -> c) -> TheseTable Expr a b -> c
229320theseTable f g h TheseTable {here, there} =
230321 maybeTable
231322 (maybeTable undefined f here)
232323 (\b -> maybeTable (g b) (`h` b) here)
233324 there
325+
326+
327+-- | Lift a pair of aggregating functions to operate on an 'TheseTable'.
328+-- @thisTable@s, @thatTable@s and @thoseTable@s are grouped separately.
329+aggregateTheseTable :: ()
330+ => (exprs -> aggregates)
331+ -> (exprs' -> aggregates')
332+ -> TheseTable Expr exprs exprs'
333+ -> TheseTable Aggregate aggregates aggregates'
334+aggregateTheseTable f g (TheseTable here there) = TheseTable
335+ { here = aggregateMaybeTable f here
336+ , there = aggregateMaybeTable g there
337+ }
338+
339+
340+-- | Construct a 'TheseTable' in the 'Name' context. This can be useful if you
341+-- have a 'TheseTable' that you are storing in a table and need to construct a
342+-- 'TableSchema'.
343+nameTheseTable :: ()
344+ => Name (Maybe MaybeTag)
345+ -- ^ The name of the column to track the presence of the @a@ table.
346+ -> Name (Maybe MaybeTag)
347+ -- ^ The name of the column to track the presence of the @b@ table.
348+ -> a
349+ -- ^ Names of the columns in the @a@ table.
350+ -> b
351+ -- ^ Names of the columns in the @b@ table.
352+ -> TheseTable Name a b
353+nameTheseTable here there a b =
354+ TheseTable
355+ { here = nameMaybeTable here a
356+ , there = nameMaybeTable there b
357+ }
src/Rel8/Table/Transpose.hsnew file+46
@@ -0,0 +1,46 @@
1+{-# language DataKinds #-}
2+{-# language FlexibleInstances #-}
3+{-# language FunctionalDependencies #-}
4+{-# language StandaloneKindSignatures #-}
5+{-# language TypeFamilies #-}
6+{-# language UndecidableInstances #-}
7+
8+module Rel8.Table.Transpose
9+ ( Transposes
10+ )
11+where
12+
13+-- base
14+import Data.Kind ( Constraint, Type )
15+import Prelude ()
16+
17+-- rel8
18+import qualified Rel8.Schema.Kind as K
19+import Rel8.Table ( Table, Transpose, Congruent )
20+
21+
22+-- | @'Transposes' from to a b@ means that @a@ and @b@ are 'Table's, in the
23+-- @from@ and @to@ contexts respectively, which share the same underlying
24+-- structure. In other words, @b@ is a version of @a@ transposed from the
25+-- @from@ context to the @to@ context (and vice versa).
26+type Transposes :: K.Context -> K.Context -> Type -> Type -> Constraint
27+class
28+ ( Table from a
29+ , Table to b
30+ , Congruent a b
31+ , b ~ Transpose to a
32+ , a ~ Transpose from b
33+ )
34+ => Transposes from to a b
35+ | a -> from
36+ , b -> to
37+ , a to -> b
38+ , b from -> a
39+instance
40+ ( Table from a
41+ , Table to b
42+ , Congruent a b
43+ , b ~ Transpose to a
44+ , a ~ Transpose from b
45+ )
46+ => Transposes from to a b
src/Rel8/Table/Undefined.hs+7−7
@@ -11,16 +11,16 @@ where
1111import Prelude hiding ( undefined )
1212
1313-- rel8
14+import Rel8.Expr ( Expr )
1415import Rel8.Expr.Null ( snull, unsafeUnnullify )
15−import Rel8.Schema.Context ( DB( DB ) )
1616import Rel8.Schema.HTable ( htabulate, hfield, hspecs )
17−import Rel8.Schema.Nullability ( Nullability( Nullable, NonNullable ) )
18−import Rel8.Schema.Spec ( SSpec(..) )
17+import Rel8.Schema.Null ( Nullity( Null, NotNull ) )
18+import Rel8.Schema.Spec ( Spec(..) )
1919import Rel8.Table ( Table, fromColumns )
2020
2121
22−undefined :: Table DB a => a
22+undefined :: Table Expr a => a
2323undefined = fromColumns $ htabulate $ \field -> case hfield hspecs field of
24− SSpec {nullability, info} -> case nullability of
25− Nullable -> DB (snull Nullable info)
26− NonNullable -> DB (unsafeUnnullify (snull Nullable info))
24+ Spec {nullity, info} -> case nullity of
25+ Null -> snull info
26+ NotNull -> unsafeUnnullify (snull info)
src/Rel8/Table/Window.hsnew file+43
@@ -0,0 +1,43 @@
1+{-# language MonoLocalBinds #-}
2+
3+module Rel8.Table.Window
4+ ( cumulative
5+ , cumulative_
6+ , currentRow
7+ )
8+where
9+
10+-- base
11+import Prelude
12+
13+-- opaleye
14+import qualified Opaleye.Window as Opaleye
15+
16+-- rel8
17+import Rel8.Aggregate ( Aggregates )
18+import qualified Rel8.Expr.Window as Expr
19+import Rel8.Schema.HTable ( hfield, htabulateA )
20+import Rel8.Table ( fromColumns, toColumns )
21+import Rel8.Window ( Window( Window ) )
22+
23+
24+-- | 'cumulative' allows the use of aggregation functions in 'Window'
25+-- expressions. In particular, @'cumulative' 'Rel8.sum'@
26+-- (when combined with 'Rel8.Window.orderPartitionBy') gives a running total,
27+-- also known as a \"cumulative sum\", hence the name @cumulative@.
28+cumulative :: Aggregates aggregates exprs => (a -> aggregates) -> Window a exprs
29+cumulative f =
30+ fmap fromColumns $
31+ htabulateA $ \field ->
32+ Expr.cumulative ((`hfield` field) . toColumns . f)
33+
34+
35+-- | A version of 'cumulative' for use with nullary aggregators like
36+-- 'Rel8.Expr.Aggregate.countStar'.
37+cumulative_ :: Aggregates aggregates exprs => aggregates -> Window a exprs
38+cumulative_ = cumulative . const
39+
40+
41+-- | Return every column of the current row of a window query.
42+currentRow :: Window a a
43+currentRow = Window $ Opaleye.over (Opaleye.noWindowFunction id) mempty mempty
src/Rel8/Tabulate.hs+549−141
@@ -1,232 +1,640 @@
1−{-# language DeriveFunctor #-}
2−{-# language DerivingStrategies #-}
31{-# language FlexibleContexts #-}
2+{-# language MonoLocalBinds #-}
3+{-# language ScopedTypeVariables #-}
4+{-# language StandaloneKindSignatures #-}
5+{-# language TypeApplications #-}
46{-# language TupleSections #-}
7+{-# language UndecidableInstances #-}
8+
9+-- | "Rel8.Tabulate" provides an alternative API ('Tabulation') for writing
10+-- queries that complements the main "Rel8" API ('Query').
511
612module Rel8.Tabulate
7− ( Tabulation
8− , runTabulation
9− , tabulate
10− , tabulateA
13+ (
14+ Tabulation
15+
16+ -- * Interfacing with 'Query's
1117 , fromQuery
18+ , toQuery
1219 , liftQuery
13− , prebind
14− , postbind
15− , indexed
16− , ifilter
20+ , through
1721 , lookup
22+
23+ -- * Aggregation and Ordering
24+ , aggregate
25+ , distinct
26+ , order
27+
28+ -- ** Magic 'Tabulation's
29+ -- $magic
30+ , count
31+ , optional
32+ , many
33+ , some
34+ , exists
35+ , present
36+ , absent
37+
38+ -- * Natural joins
1839 , align
1940 , alignWith
2041 , leftAlign
2142 , leftAlignWith
43+ , rightAlign
44+ , rightAlignWith
2245 , zip
2346 , zipWith
2447 , similarity
2548 , difference
26− , aggregateTabulation
27− , optionalTabulation
2849 )
2950where
3051
3152-- base
32−import Control.Applicative ( liftA2 )
33−import Control.Monad ( join, liftM2 )
34−import Data.Bifunctor ( bimap, first )
53+import Control.Applicative ( (<|>), empty, liftA2 )
54+import Control.Monad ( liftM2 )
55+import Data.Bifunctor ( Bifunctor, bimap, first, second )
3556import Data.Foldable ( traverse_ )
36−import Data.Maybe ( fromMaybe )
37−import Prelude hiding ( filter, lookup, undefined, zip, zipWith )
57+import Data.Function ( on )
58+import Data.Functor.Contravariant ( Contravariant, (>$<), contramap )
59+import Data.Int ( Int64 )
60+import Data.Kind ( Type )
61+import Data.Maybe ( fromJust, fromMaybe )
62+import Prelude hiding ( lookup, zip, zipWith )
63+
64+-- bifunctors
65+import Data.Bifunctor.Clown ( Clown( Clown ), runClown )
66+
67+-- comonad
68+import Control.Comonad ( extract )
69+
70+-- opaleye
71+import qualified Opaleye.Aggregate as Opaleye
72+import qualified Opaleye.Order as Opaleye ( orderBy, distinctOnExplicit )
73+
74+-- profunctors
75+import Data.Profunctor ( dimap, lmap )
76+
77+-- product-profunctors
78+import Data.Profunctor.Product
79+ ( ProductProfunctor, (***!)
80+ , SumProfunctor, (+++!)
81+ )
82+import qualified Data.Profunctor.Product as PP
3883
3984-- rel8
40−import Rel8.Aggregate ( Aggregate )
85+import Rel8.Aggregate ( Aggregates )
4186import Rel8.Expr ( Expr )
42−import Rel8.Expr.Bool ( not_, true )
87+import Rel8.Expr.Aggregate ( countStar )
88+import Rel8.Expr.Bool ( true )
89+import Rel8.Order ( Order( Order ) )
4390import Rel8.Query ( Query )
44−import Rel8.Query.Aggregate ( aggregate )
45−import Rel8.Query.Exists ( withBy, withoutBy )
46−import Rel8.Query.Filter ( filter, where_ )
47−import Rel8.Query.Maybe ( optional )
91+import qualified Rel8.Query.Exists as Q ( exists, present, absent )
92+import Rel8.Query.Filter ( where_ )
93+import Rel8.Query.List ( catNonEmptyTable )
94+import qualified Rel8.Query.Maybe as Q ( optional )
95+import Rel8.Query.Opaleye ( mapOpaleye, unsafePeekQuery )
96+import Rel8.Query.Rebind ( rebind )
4897import Rel8.Query.These ( alignBy )
49−import Rel8.Schema.Context ( DB )
50−import Rel8.Table ( Table )
51−import Rel8.Table.Aggregate ( groupBy )
52−import Rel8.Table.Eq ( EqTable, (==:) )
53−import Rel8.Table.Maybe ( MaybeTable )
54−import Rel8.Table.These ( TheseTable, theseTable )
55−import Rel8.Table.Undefined ( undefined )
98+import Rel8.Table ( Table, fromColumns, toColumns )
99+import Rel8.Table.Aggregate ( hgroupBy, listAgg, nonEmptyAgg )
100+import Rel8.Table.Alternative
101+ ( AltTable, (<|>:)
102+ , AlternativeTable, emptyTable
103+ )
104+import Rel8.Table.Cols ( fromCols, toCols )
105+import Rel8.Table.Eq ( EqTable, (==:), eqTable )
106+import Rel8.Table.List ( ListTable( ListTable ) )
107+import Rel8.Table.Maybe ( MaybeTable( MaybeTable ), maybeTable )
108+import Rel8.Table.NonEmpty ( NonEmptyTable( NonEmptyTable ) )
109+import Rel8.Table.Opaleye ( aggregator, unpackspec )
110+import Rel8.Table.Ord ( OrdTable )
111+import Rel8.Table.Order ( ascTable )
112+import Rel8.Table.Projection
113+ ( Biprojectable, biproject
114+ , Projectable, project
115+ , apply
116+ )
117+import Rel8.Table.These ( TheseTable( TheseTable ), theseTable )
56118
57119-- semigroupoids
58120import Data.Functor.Apply ( Apply, liftF2 )
59−import Data.Functor.Bind ( Bind )
60−import qualified Data.Functor.Bind
61−import Data.Semigroup.Traversable.Class ( bitraverse1 )
121+import Data.Functor.Bind ( Bind, (>>-) )
122+
123+
124+type Key :: Type -> Type
125+type Key = Maybe
126+
127+
128+cat :: Table Expr k => Key k -> Query k
129+cat = maybe emptyTable pure
130+
131+
132+key :: (ProductProfunctor p, SumProfunctor p)
133+ => p a b -> p (Key a) (Key b)
134+key a = dimap from to (PP.empty +++! a)
135+ where
136+ from = maybe (Left ()) Right
137+ to = either (const Nothing) Just
138+
139+
140+keyed :: (ProductProfunctor p, SumProfunctor p)
141+ => p k l -> p a b -> p (Key k, a) (Key l, b)
142+keyed k a = key k ***! a
143+
144+
145+type Predicate :: Type -> Type
146+newtype Predicate a = Predicate (Maybe (a -> Expr Bool))
147+
148+
149+instance Contravariant Predicate where
150+ contramap f (Predicate a) = Predicate (lmap f <$> a)
151+
152+
153+instance Semigroup (Predicate k) where
154+ Predicate ma <> Predicate mb = Predicate $ ma <|> mb
155+
156+
157+instance Monoid (Predicate k) where
158+ mempty = Predicate Nothing
159+
160+
161+match :: EqTable k => Key k -> Predicate k
162+match = Predicate . fmap (==:)
163+
164+
165+ensure :: Predicate k -> Key k -> Query ()
166+ensure (Predicate mp) = traverse_ (\k -> traverse_ (\p -> where_ (p k)) mp)
167+
168+
169+-- | A @'Tabulation' k a@ is like a @'Query' a@, except that each row also
170+-- has a key @k@ in addition to the value @a@. 'Tabulation's can be composed
171+-- monadically just like 'Query's, but the resulting join is more like a
172+-- @NATURAL JOIN@ (based on the common key column(s) @k@) than the
173+-- @CROSS JOIN@ given by 'Query'.
174+--
175+-- Another way to think of @'Tabulation' k a@ is as analogous to @Map k a@ in
176+-- the same way @'Query' a@ is analogous to @[a]@. However, there's nothing
177+-- stopping a 'Tabulation' from containing multiple rows with the same key, so
178+-- technically @Map k (NonEmpty a)@ is more accurate.
179+--
180+-- 'Tabulation's can be created from 'Query's with 'fromQuery' and 'liftQuery'
181+-- and converted back to 'Query's with 'lookup' and 'toQuery' (though note the
182+-- caveats that come with the latter).
183+type Tabulation :: Type -> Type -> Type
184+newtype Tabulation k a = Tabulation (Predicate k -> Query (Key k, a))
62185
63186
64−newtype Tabulation k a = Tabulation (k -> Query (Maybe k, a))
65− deriving stock Functor
187+instance Biprojectable Tabulation where
188+ biproject f g =
189+ bimap
190+ (fromColumns . apply f . toColumns)
191+ (fromColumns . apply g . toColumns)
66192
67193
194+instance Bifunctor Tabulation where
195+ bimap f g (Tabulation a) = Tabulation $ \p ->
196+ bimap (fmap f) g <$> a (f >$< p)
197+
198+
199+instance Functor (Tabulation k) where
200+ fmap = second
201+
202+
203+instance Projectable (Tabulation k) where
204+ project f = fmap (fromColumns . apply f . toColumns)
205+
206+
207+-- | If @'Tabulation' k a@ is @Map k (NonEmpty a)@, then @(<.>)@ is
208+-- @intersectionWith (liftA2 (<*>))@
68209instance EqTable k => Apply (Tabulation k) where
69210 liftF2 = liftA2
70211
71212
213+-- | @pure = 'liftQuery' . pure@
72214instance EqTable k => Applicative (Tabulation k) where
73215 pure = liftQuery . pure
74216 liftA2 = liftM2
75217
76218
77219instance EqTable k => Bind (Tabulation k) where
78− join = join
220+ Tabulation as >>- f = Tabulation $ \p -> do
221+ (k, a) <- as p
222+ case f a of
223+ Tabulation bs -> do
224+ let p' = match k
225+ (k', b) <- bs (p' <> p)
226+ ensure p' k'
227+ pure (k' <|> k, b)
79228
80229
81230instance EqTable k => Monad (Tabulation k) where
82− Tabulation as >>= f = Tabulation $ \i -> do
83− (mk, a) <- as i
84− case mk of
85− Nothing -> case f a of
86− Tabulation bs -> bs i
87− Just k -> case f a of
88− Tabulation bs -> do
89− (mk', b) <- bs k
90− case mk' of
91− Nothing -> pure (mk, b)
92− Just k' -> do
93− where_ $ k ==: k'
94− pure (mk', b)
95−
96−
97−runTabulation :: EqTable k => Tabulation k a -> Query (k, a)
98−runTabulation (Tabulation f) = do
99− (mk, a) <- f i
100− case mk of
101− Nothing -> do
102− -- Opaleye tries to be too clever optimising "WHERE FALSE" and generates
103− -- invalid SQL, so we use "WHERE NOT TRUE" instead
104− where_ $ not_ true
105− pure (i, a)
106− Just k -> pure (k, a)
107− where
108− i = undefined
231+ (>>=) = (>>-)
109232
110233
111−liftQuery :: Query a -> Tabulation k a
112−liftQuery query = Tabulation $ const $ fmap (Nothing,) query
234+-- | If @'Tabulation' k a@ is @Map k (NonEmpty a)@, then @(<|>:)@ is
235+-- @unionWith (<>)@.
236+instance EqTable k => AltTable (Tabulation k) where
237+ tas <|>: tbs = do
238+ eas <- peek tas
239+ ebs <- peek tbs
240+ case (eas, ebs) of
241+ (Left as, Left bs) -> liftQuery $ as <|>: bs
242+ (Right as, Right bs) -> fromQuery $ as <|>: bs
243+ _ -> catNonEmptyTable `through` ((<>) `on` some) tas tbs
113244
114245
115−tabulate :: (a -> k) -> a -> Tabulation k a
116−tabulate key a = fromQuery $ pure (key a, a)
246+instance EqTable k => AlternativeTable (Tabulation k) where
247+ emptyTable = Tabulation $ const $ fmap (empty,) emptyTable
117248
118249
119−tabulateA :: (a -> Query k) -> a -> Tabulation k a
120−tabulateA key a = fromQuery $ (,a) <$> key a
250+-- | If @'Tabulation' k a@ is @Map k (NonEmpty a)@, then @(<>)@ is
251+-- @unionWith (liftA2 (<>))@.
252+instance (EqTable k, Table Expr a, Semigroup a) => Semigroup (Tabulation k a)
253+ where
254+ (<>) = alignWith (theseTable id id (<>))
121255
122256
123−fromQuery :: Query (k, a) -> Tabulation k a
124−fromQuery = Tabulation . const . fmap (first Just)
257+instance (EqTable k, Table Expr a, Semigroup a) => Monoid (Tabulation k a)
258+ where
259+ mempty = emptyTable
125260
126261
127−indexed :: Tabulation k a -> Tabulation k (k, a)
128−indexed (Tabulation query) = Tabulation $ \i ->
129− (\(mk, a) -> (mk, (fromMaybe i mk, a))) <$> query i
262+-- | Any 'Query' of key-value pairs @(k, a)@ can be a @'Tabulation' k a@.
263+fromQuery :: Query (k, a) -> Tabulation k a
264+fromQuery = Tabulation . const . fmap (first pure)
265+
266+
267+-- | Convert a @'Tabulation' k a@ back into a 'Query' of key-value pairs.
268+--
269+-- Note that the result of a 'toQuery' is undefined (will always return zero
270+-- rows) on 'Tabulation's constructed with 'liftQuery' or 'pure'. So while
271+-- @toQuery . fromQuery@ is always @id@, @fromQuery . toQuery@ is not.
272+--
273+-- A safer, more predictable alternative to 'toQuery' is to use 'lookup' with
274+-- an explicit set of keys:
275+--
276+-- @
277+-- do
278+-- k <- keys
279+-- a <- lookup k tabulation
280+-- pure (k, a)
281+-- @
282+--
283+-- Having said that, in practice, most legitimate uses of 'Tabulation' will
284+-- have a well-defined 'toQuery'. It would be possible in theory to encode
285+-- the necessary invariants at the type level using an indexed monad, but we
286+-- would lose the ability to use @do@-notation, which is the main benefit
287+-- of having 'Tabulation' as a monad in the first place.
288+--
289+-- In particular, @'toQuery' t@ is well-defined for any 'Tabulation' @t@
290+-- defined as @t = fromQuery _@. @'toQuery' t@ is also well-defined for any
291+-- 'Tabulation' @t@ defined as @t = t' >>= _@ or @t = t' *> _@ where
292+-- @'toQuery' t'@ is well-defined. There are other valid permutations too.
293+-- Generally, anything that uses 'fromQuery' at some point, unless wrapped in
294+-- a top-level 'present' or 'absent', will have a well-defined 'toQuery'.
295+toQuery :: Table Expr k => Tabulation k a -> Query (k, a)
296+toQuery (Tabulation f) = do
297+ (mk, a) <- f mempty
298+ k <- cat mk
299+ pure (k, a)
300+
301+
302+-- | A @'Query' a@ can be treated as a @'Tabulation' k a@ where the given @a@
303+-- values exist at every possible key @k@.
304+liftQuery :: Query a -> Tabulation k a
305+liftQuery = Tabulation . const . fmap (empty,)
130306
131307
132−ifilter :: (k -> a -> Expr Bool) -> Tabulation k a -> Tabulation k a
133−ifilter f tabulation = snd <$> do
134− filter (uncurry f) `postbind` indexed tabulation
308+-- | Run a Kleisli arrow in the the 'Query' monad \"through\" a 'Tabulation'.
309+-- Useful for 'Rel8.filter'ing a 'Tabulation'.
310+--
311+-- @
312+-- 'Rel8.filter' ((>=. 30) . userAge) `'through'` usersById
313+-- @
314+through :: (a -> Query b) -> Tabulation k a -> Tabulation k b
315+through f (Tabulation as) = Tabulation $ \p -> do
316+ (k, a) <- as p
317+ b <- f a
318+ pure (k, b)
319+infixr 1 `through`
135320
136321
137−prebind :: (a -> Tabulation k b) -> Query a -> Tabulation k b
138−prebind f as = Tabulation $ \k -> do
139− a <- as
140− case f a of
141− Tabulation query -> query k
142−infixr 1 `prebind`
322+-- | @'lookup' k t@ returns the value(s) at the key @k@ in the tabulation @t@.
323+lookup :: EqTable k => k -> Tabulation k a -> Query a
324+lookup k (Tabulation f) = do
325+ (k', a) <- f p
326+ ensure p k'
327+ pure a
328+ where
329+ p = match (pure k)
143330
144331
145−postbind :: (a -> Query b) -> Tabulation k a -> Tabulation k b
146−postbind f (Tabulation as) = Tabulation $ \i -> do
147− (k, a) <- as i
148− case f a of
149− bs -> do
150− b <- bs
151− pure (k, b)
152−infixr 1 `postbind`
332+-- | 'aggregate' aggregates the values within each key of a
333+-- 'Tabulation'. There is an implicit @GROUP BY@ on all the key columns.
334+aggregate :: forall k aggregates exprs.
335+ ( EqTable k
336+ , Aggregates aggregates exprs
337+ )
338+ => Tabulation k aggregates -> Tabulation k exprs
339+aggregate (Tabulation f) = Tabulation $
340+ mapOpaleye (Opaleye.aggregate (keyed haggregator aggregator)) .
341+ fmap (first (fmap (hgroupBy (eqTable @k) . toColumns))) .
342+ f
343+ where
344+ haggregator = dimap fromColumns fromCols aggregator
153345
154346
155−lookup :: EqTable k => k -> Tabulation k a -> Query a
156−lookup key (Tabulation query) = do
157− (mk, a) <- query key
158− traverse_ (where_ . (key ==:)) mk
159− pure a
347+-- | 'distinct' ensures a 'Tabulation' has at most one value for
348+-- each key, i.e., it drops duplicates. In general it keeps only the
349+-- \"first\" value it encounters for each key, but note that \"first\" is
350+-- undefined unless you first call 'order'.
351+distinct :: EqTable k => Tabulation k a -> Tabulation k a
352+distinct (Tabulation f) = Tabulation $
353+ mapOpaleye (Opaleye.distinctOnExplicit (key unpackspec) fst) . f
160354
161355
162−align :: (EqTable k, Table DB a, Table DB b)
163− => Tabulation k a -> Tabulation k b -> Tabulation k (TheseTable a b)
356+-- | 'order' orders the /values/ of a 'Tabulation' within their
357+-- respective keys. This specifies a defined order for 'distinct'.
358+-- It also defines the order of the lists produced by 'many' and
359+-- 'some'.
360+order :: OrdTable k => Order a -> Tabulation k a -> Tabulation k a
361+order ordering (Tabulation f) =
362+ Tabulation $ mapOpaleye (Opaleye.orderBy ordering') . f
363+ where
364+ Order ordering' = runClown (keyed (Clown ascTable) (Clown ordering))
365+
366+
367+-- $magic
368+--
369+-- Some of the following combinators produce \"magic\" 'Tabulation's. Let's
370+-- use 'count' as an example to demonstrate this concept. Consider
371+-- the following:
372+--
373+-- @
374+-- count $ fromQuery $ values
375+-- [ (lit 'a', lit True)
376+-- , (lit 'a', lit False)
377+-- , (lit 'b', lit True)
378+-- ]
379+-- @
380+--
381+-- You might expect this to be equivalent to the following 'Tabulation':
382+--
383+-- @
384+-- fromQuery $ values
385+-- [ (lit 'a', 2)
386+-- , (lit 'b', 1)
387+-- ]
388+-- @
389+--
390+-- However, it isn't quite. While the resulting 'Tabulation' does effectively
391+-- contain the above entries, it also behaves as though it contained the value
392+-- @0@ at every other possible key.
393+--
394+-- This means you can do:
395+--
396+-- @
397+-- do
398+-- user <- usersById
399+-- orderCount <- count ordersByUserId
400+-- @
401+--
402+-- To see how many orders a user has (getting @0@ if they have no orders).
403+
404+
405+-- | 'count' returns a count of how many entries are in the given
406+-- 'Tabulation' at each key.
407+--
408+-- The resulting 'Tabulation' is \"magic\" in that the value @0@ exists at
409+-- every possible key that wasn't in the given 'Tabulation'.
410+count :: EqTable k => Tabulation k a -> Tabulation k (Expr Int64)
411+count =
412+ fmap (maybeTable 0 id) .
413+ optional .
414+ aggregate .
415+ fmap (const countStar)
416+
417+
418+-- | 'optional' produces a \"magic\" 'Tabulation' whereby each
419+-- entry in the given 'Tabulation' is wrapped in 'Rel8.justTable', and every
420+-- other possible key contains a single 'Rel8.nothingTable'.
421+--
422+-- This is used to implement 'leftAlignWith'.
423+optional :: Tabulation k a -> Tabulation k (MaybeTable Expr a)
424+optional (Tabulation f) = Tabulation $ \p -> case p of
425+ Predicate Nothing -> fmap pure <$> f p
426+ _ -> fmap (\m -> (empty, snd <$> m)) $ Q.optional $ do
427+ (k, a) <- f p
428+ ensure p k
429+ pure (k, a)
430+
431+
432+-- | 'many' aggregates each entry with a particular key into a
433+-- single entry with all of the values contained in a 'ListTable'.
434+--
435+-- 'order' can be used to give this 'ListTable' a defined order.
436+--
437+-- The resulting 'Tabulation' is \"magic\" in that the value
438+-- @'Rel8.listTable []'@ exists at every possible key that wasn't in the given
439+-- 'Tabulation'.
440+many :: (EqTable k, Table Expr a)
441+ => Tabulation k a -> Tabulation k (ListTable Expr a)
442+many =
443+ fmap (maybeTable mempty (\(ListTable a) -> ListTable a)) .
444+ optional .
445+ aggregate .
446+ fmap (listAgg . toCols)
447+
448+
449+-- | 'some' aggregates each entry with a particular key into a
450+-- single entry with all of the values contained in a 'NonEmptyTable'.
451+--
452+-- 'order' can be used to give this 'NonEmptyTable' a defined order.
453+some :: (EqTable k, Table Expr a)
454+ => Tabulation k a -> Tabulation k (NonEmptyTable Expr a)
455+some =
456+ fmap (\(NonEmptyTable a) -> NonEmptyTable a) .
457+ aggregate .
458+ fmap (nonEmptyAgg . toCols)
459+
460+
461+-- | 'exists' produces a \"magic\" 'Tabulation' which contains the
462+-- value 'Rel8.true' at each key in the given 'Tabulation', and the value
463+-- 'Rel8.false' at every other possible key.
464+exists :: Tabulation k a -> Tabulation k (Expr Bool)
465+exists (Tabulation f) = Tabulation $ \p -> case p of
466+ Predicate Nothing -> (true <$) <$> f p
467+ _ -> fmap (empty,) $ Q.exists $ do
468+ (k, _) <- f p
469+ ensure p k
470+
471+
472+-- | 'present' produces a 'Tabulation' where a single @()@ row
473+-- exists for every key that was present in the given 'Tabulation'.
474+--
475+-- This is used to implement 'similarity'.
476+present :: Tabulation k a -> Tabulation k ()
477+present (Tabulation f) = Tabulation $ \p -> do
478+ Q.present $ do
479+ (k, _) <- f p
480+ ensure p k
481+ pure (empty, ())
482+
483+
484+-- | 'absent' produces a 'Tabulation' where a single @()@ row exists
485+-- at every possible key that absent from the given 'Tabulation'.
486+--
487+-- This is used to implement 'difference'.
488+absent :: Tabulation k a -> Tabulation k ()
489+absent (Tabulation f) = Tabulation $ \p -> do
490+ Q.absent $ do
491+ (k, _) <- f p
492+ ensure p k
493+ pure (empty, ())
494+
495+
496+-- | Performs a @NATURAL FULL OUTER JOIN@ based on the common key columns.
497+--
498+-- Analogous to 'Data.Semialign.align'.
499+align :: EqTable k
500+ => Tabulation k a -> Tabulation k b -> Tabulation k (TheseTable Expr a b)
164501align = alignWith id
165502
166503
167−alignWith :: (EqTable k, Table DB a, Table DB b)
168− => (TheseTable a b -> c)
504+-- | Performs a @NATURAL FULL OUTER JOIN@ based on the common key columns.
505+--
506+-- Analogous to 'Data.Semialign.alignWith'.
507+alignWith :: EqTable k
508+ => (TheseTable Expr a b -> c)
169509 -> Tabulation k a -> Tabulation k b -> Tabulation k c
170−alignWith f kas kbs = do
171− as <- toQuery kas
172− bs <- toQuery kbs
173− fromQuery $ do
174− tkab <- alignBy (\(l, _) (m, _) -> l ==: m) as bs
175− let
176− k' = theseTable fst fst (const fst) tkab
177− tab = bimap snd snd tkab
178− pure (k', f tab)
179−
180−
510+alignWith f (Tabulation as) (Tabulation bs) = Tabulation $ \p -> do
511+ tkab <- liftF2 (alignBy condition) as bs p
512+ k <- traverse (rebind "key") $ recover $ bimap fst fst tkab
513+ let
514+ tab = bimap snd snd tkab
515+ pure (k, f tab)
516+ where
517+ condition (k, _) (k', _) = fromMaybe true (liftA2 (==:) k k')
518+ recover (TheseTable mma@(MaybeTable _ ma) mmb@(MaybeTable _ mb)) =
519+ case extract ma of
520+ Nothing -> extract mb
521+ Just a -> case extract mb of
522+ Nothing -> extract ma
523+ Just b -> case a <$ mma <|>: b <$ mmb of
524+ MaybeTable _ c -> pure (extract c)
525+
526+
527+-- | Performs a @NATURAL LEFT OUTER JOIN@ based on the common key columns.
528+--
529+-- Analogous to 'Data.Semialign.rpadZip'.
530+--
531+-- Note that you can achieve the same effect with 'optional' and the
532+-- 'Applicative' instance for 'Tabulation', i.e., this is just
533+-- @\left right -> liftA2 (,) left (optional right). You can also
534+-- use @do@-notation.
181535leftAlign :: EqTable k
182− => Tabulation k a -> Tabulation k b -> Tabulation k (a, MaybeTable b)
536+ => Tabulation k a -> Tabulation k b -> Tabulation k (a, MaybeTable Expr b)
183537leftAlign = leftAlignWith (,)
184538
185539
540+-- | Performs a @NATURAL LEFT OUTER JOIN@ based on the common key columns.
541+--
542+-- Analogous to 'Data.Semialign.rpadZipWith'.
543+--
544+-- Note that you can achieve the same effect with 'optional' and the
545+-- 'Applicative' instance for 'Tabulation', i.e., this is just
546+-- @\f left right -> liftA2 f left (optional right). You can also
547+-- use @do@-notation.
186548leftAlignWith :: EqTable k
187− => (a -> MaybeTable b -> c)
549+ => (a -> MaybeTable Expr b -> c)
188550 -> Tabulation k a -> Tabulation k b -> Tabulation k c
189−leftAlignWith f left right = liftA2 f left (optionalTabulation right)
551+leftAlignWith f left right = liftA2 f left (optional right)
552+
553+
554+-- | Performs a @NATURAL RIGHT OUTER JOIN@ based on the common key columns.
555+--
556+-- Analogous to 'Data.Semialign.lpadZip'.
557+--
558+-- Note that you can achieve the same effect with 'optional' and the
559+-- 'Applicative' instance for 'Tabulation', i.e., this is just
560+-- @\left right -> liftA2 (flip (,)) right (optional left). You can
561+-- also use @do@-notation.
562+rightAlign :: EqTable k
563+ => Tabulation k a -> Tabulation k b -> Tabulation k (MaybeTable Expr a, b)
564+rightAlign = rightAlignWith (,)
565+
566+
567+-- | Performs a @NATURAL RIGHT OUTER JOIN@ based on the common key columns.
568+--
569+-- Analogous to 'Data.Semialign.lpadZipWith'.
570+--
571+-- Note that you can achieve the same effect with 'optional' and the
572+-- 'Applicative' instance for 'Tabulation', i.e., this is just
573+-- @\f left right -> liftA2 (flip f) right (optional left). You can
574+-- also use @do@-notation.
575+rightAlignWith :: EqTable k
576+ => (MaybeTable Expr a -> b -> c)
577+ -> Tabulation k a -> Tabulation k b -> Tabulation k c
578+rightAlignWith f left right = liftA2 (flip f) right (optional left)
190579
191580
581+-- | Performs a @NATURAL INNER JOIN@ based on the common key columns.
582+--
583+-- Analagous to 'Data.Semialign.zip'.
584+--
585+-- Note that you can achieve the same effect with the 'Applicative' instance
586+-- of 'Tabulation', i.e., this is just @'liftA2 (,)'@. You can also use
587+-- @do@-notation.
192588zip :: EqTable k
193589 => Tabulation k a -> Tabulation k b -> Tabulation k (a, b)
194590zip = zipWith (,)
195591
196592
593+-- | Performs a @NATURAL INNER JOIN@ based on the common key columns.
594+--
595+-- Analagous to 'Data.Semialign.zipWith'.
596+--
597+-- Note that you can achieve the same effect with the 'Applicative' instance
598+-- of 'Tabulation', i.e., this is just @'liftA2'@. You can also use
599+-- @do@-notation.
197600zipWith :: EqTable k
198601 => (a -> b -> c) -> Tabulation k a -> Tabulation k b -> Tabulation k c
199602zipWith = liftA2
200603
201604
605+-- | Performs a [@NATURAL SEMI JOIN@](https://en.wikipedia.org/wiki/Relational_algebra#Semijoin_%28%E2%8B%89%29%28%E2%8B%8A%29)
606+-- based on the common key columns.
607+--
608+-- The result is a subset of the left tabulation where only entries which have
609+-- a corresponding entry in the right tabulation are kept.
610+--
611+-- Note that you can achieve a similar effect with 'present' and the
612+-- 'Applicative' instance of 'Tabulation', i.e., this is just
613+-- @\left right -> left <* present right@. You can also use
614+-- @do@-notation.
202615similarity :: EqTable k => Tabulation k a -> Tabulation k b -> Tabulation k a
203−similarity kas kbs = do
204− as <- toQuery kas
205− bs <- toQuery kbs
206− fromQuery $ as >>= withBy (\(k, _) (l, _) -> k ==: l) bs
207−
208−
616+similarity a b = a <* present b
617+
618+
619+-- | Performs a [@NATURAL ANTI JOIN@](https://en.wikipedia.org/wiki/Relational_algebra#Antijoin_%28%E2%96%B7%29)
620+-- based on the common key columns.
621+--
622+-- The result is a subset of the left tabulation where only entries which do
623+-- not have a corresponding entry in the right tabulation are kept.
624+--
625+-- Note that you can achieve a similar effect with 'absent' and the
626+-- 'Applicative' instance of 'Tabulation', i.e., this is just
627+-- @\left right -> left <* absent right@. You can also use
628+-- @do@-notation.
209629difference :: EqTable k => Tabulation k a -> Tabulation k b -> Tabulation k a
210−difference kas kbs = do
211− as <- toQuery kas
212− bs <- toQuery kbs
213− fromQuery $ as >>= withoutBy (\(k, _) (l, _) -> k ==: l) bs
214−
215−
216−aggregateTabulation :: EqTable k
217− => Tabulation k (Aggregate a) -> Tabulation k a
218−aggregateTabulation kas = do
219− as <- toQuery kas
220− fromQuery $ aggregate $ bitraverse1 groupBy id <$> as
221−
222−
223−optionalTabulation :: EqTable k
224− => Tabulation k a -> Tabulation k (MaybeTable a)
225−optionalTabulation as = Tabulation $ \k -> do
226− ma <- optional $ lookup k as
227− pure (Just k, ma)
630+difference a b = a <* absent b
228631
229632
230−toQuery :: Tabulation k a -> Tabulation k (Query (k, a))
231−toQuery (Tabulation as) = Tabulation $ \k ->
232− pure (Nothing, first (fromMaybe k) <$> as k)
633+-- | 'Tabulation's can be produced with either 'fromQuery' or 'liftQuery', and
634+-- in some cases we might want to treat these differently. 'peek' uses
635+-- 'unsafePeekQuery' to determine which type of 'Tabulation' we have.
636+peek :: Tabulation k a -> Tabulation k (Either (Query a) (Query (k, a)))
637+peek (Tabulation f) = Tabulation $ \p ->
638+ pure $ (empty,) $ case unsafePeekQuery (f p) of
639+ (Nothing, _) -> Left $ fmap snd (f p)
640+ (Just _, _) -> Right $ fmap (first fromJust) (f p)
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