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.github/workflows/build.yaml+26 Changelog.md+159 Doctest.hs−53 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+80−55 shell.nix+4−4 src/Rel8.hs+386−400 src/Rel8/Aggregate.hs+45−150 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+47−75 src/Rel8/Expr.hs-boot+5−4 src/Rel8/Expr/Aggregate.hs+58−87 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+29−60 src/Rel8/Expr/Function.hs+2−33 src/Rel8/Expr/Null.hs+26−39 src/Rel8/Expr/Num.hs+68−15 src/Rel8/Expr/Opaleye.hs+27−13 src/Rel8/Expr/Ord.hs+33−53 src/Rel8/Expr/Order.hs−12 src/Rel8/Expr/Sequence.hs+22 src/Rel8/Expr/Serialize.hs+16−15 src/Rel8/Expr/Text.hs+66−11 src/Rel8/Expr/Time.hs+27−26 src/Rel8/Expr/Window.hs+121 src/Rel8/FCF.hs+9−1 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+5−14 src/Rel8/Query.hs+181−8 src/Rel8/Query.hs-boot+3−1 src/Rel8/Query/Aggregate.hs+36−3 src/Rel8/Query/Distinct.hs+4−12 src/Rel8/Query/Each.hs+4−8 src/Rel8/Query/Either.hs+34−30 src/Rel8/Query/Evaluate.hs+49 src/Rel8/Query/Exists.hs+21−49 src/Rel8/Query/Filter.hs−11 src/Rel8/Query/Indexed.hs+21 src/Rel8/Query/Limit.hs−6 src/Rel8/Query/List.hs+93−14 src/Rel8/Query/Maybe.hs+33−101 src/Rel8/Query/Null.hs+18−18 src/Rel8/Query/Opaleye.hs+41−5 src/Rel8/Query/Optimize.hs−200 src/Rel8/Query/Rebind.hs+27 src/Rel8/Query/SQL.hs+6−59 src/Rel8/Query/Set.hs+8−26 src/Rel8/Query/These.hs+62−53 src/Rel8/Query/Values.hs+1−7 src/Rel8/Query/Window.hs+26 src/Rel8/Schema/Column.hs−170 src/Rel8/Schema/Context.hs−28 src/Rel8/Schema/Context/Identity.hs−198 src/Rel8/Schema/Context/Label.hs−52 src/Rel8/Schema/Context/Nullify.hs+111−43 src/Rel8/Schema/Field.hs+37−21 src/Rel8/Schema/Generic.hs−1049 src/Rel8/Schema/Generic/Test.hs−79 src/Rel8/Schema/HTable.hs+68−38 src/Rel8/Schema/HTable/Either.hs+5−6 src/Rel8/Schema/HTable/Identity.hs+16−17 src/Rel8/Schema/HTable/Label.hs+36−51 src/Rel8/Schema/HTable/MapTable.hs+35−15 src/Rel8/Schema/HTable/Maybe.hs+5−10 src/Rel8/Schema/HTable/Nullify.hs+55−45 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+5−6 src/Rel8/Schema/HTable/Trio.hs−28 src/Rel8/Schema/HTable/Type.hs−55 src/Rel8/Schema/HTable/Vectorize.hs+51−69 src/Rel8/Schema/Insert.hs−160 src/Rel8/Schema/Kind.hs+8−14 src/Rel8/Schema/Name.hs+32−67 src/Rel8/Schema/Null.hs+110 src/Rel8/Schema/Nullability.hs−106 src/Rel8/Schema/Result.hs+54 src/Rel8/Schema/Spec.hs+18−61 src/Rel8/Schema/Spec/ConstrainDBType.hs−34 src/Rel8/Schema/Spec/ConstrainType.hs−31 src/Rel8/Schema/Structure.hs−54 src/Rel8/Schema/Table.hs+21−14 src/Rel8/Statement/Delete.hs+35−66 src/Rel8/Statement/Insert.hs+60−70 src/Rel8/Statement/OnConflict.hs+106 src/Rel8/Statement/Returning.hs+114−10 src/Rel8/Statement/SQL.hs+29 src/Rel8/Statement/Select.hs+121−35 src/Rel8/Statement/Set.hs+33 src/Rel8/Statement/Update.hs+38−80 src/Rel8/Statement/Using.hs+36 src/Rel8/Statement/View.hs+47−28 src/Rel8/Statement/Where.hs+31 src/Rel8/Table.hs+149−147 src/Rel8/Table/ADT.hs+173 src/Rel8/Table/Aggregate.hs+41−29 src/Rel8/Table/Alternative.hs+2−2 src/Rel8/Table/Bool.hs+20−6 src/Rel8/Table/Cols.hs+50 src/Rel8/Table/Either.hs+161−91 src/Rel8/Table/Eq.hs+66−35 src/Rel8/Table/HKD.hs+228 src/Rel8/Table/Insert.hs−51 src/Rel8/Table/Lifted.hs−57 src/Rel8/Table/List.hs+107−21 src/Rel8/Table/Maybe.hs+132−90 src/Rel8/Table/Name.hs+37−22 src/Rel8/Table/NonEmpty.hs+110−19 src/Rel8/Table/Null.hs+147 src/Rel8/Table/Nullify.hs+211 src/Rel8/Table/Opaleye.hs+94−74 src/Rel8/Table/Ord.hs+71−49 src/Rel8/Table/Order.hs+16−20 src/Rel8/Table/Projection.hs+73 src/Rel8/Table/Recontextualize.hs−144 src/Rel8/Table/Rel8able.hs+92 src/Rel8/Table/Serialize.hs+70−373 src/Rel8/Table/These.hs+233−108 src/Rel8/Table/Transpose.hs+46 src/Rel8/Table/Undefined.hs+6−6 src/Rel8/Table/Window.hs+43 src/Rel8/Tabulate.hs+549−140 src/Rel8/Type.hs+26−51 src/Rel8/Type/Array.hs+56−36 src/Rel8/Type/Array1D.hs−136 src/Rel8/Type/Composite.hs+135 src/Rel8/Type/Enum.hs+139 src/Rel8/Type/Eq.hs+6−37 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+8−11 src/Rel8/Type/Num.hs+18−2 src/Rel8/Type/Ord.hs+8−13 src/Rel8/Type/ReadShow.hs+14−14 src/Rel8/Type/Semigroup.hs+10−13 src/Rel8/Type/String.hs+3 src/Rel8/Type/Sum.hs+6−3 src/Rel8/Type/Tag.hs+14−1 src/Rel8/Window.hs+97 tests/Main.hs+341−193 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−53
@@ -1,53 +0,0 @@
1−{-# language BlockArguments #-}
2−{-# language OverloadedStrings #-}
3−
4−module Main where
5−
6−-- base
7−import Control.Exception ( bracket, throwIO )
8−import Data.Foldable ( traverse_ )
9−import System.Environment ( lookupEnv, setEnv )
10−
11−-- base-compat
12−import System.Environment.Compat ( unsetEnv )
13−
14−-- bytestring
15−import Data.ByteString.Char8 ( unpack )
16−
17−-- doctest
18−import Test.DocTest ( doctest )
19−
20−-- hasql
21−import Hasql.Connection ( acquire, release )
22−import Hasql.Session ( run, sql )
23−
24−-- rel8
25−import Build_doctests ( flags, module_sources, pkgs )
26−
27−-- tmp-postgres
28−import Database.Postgres.Temp ( toConnectionString, verboseConfig, with, withConfig )
29−
30−
31−main :: IO ()
32−main = do
33− nixGhcLibdir <- lookupEnv "NIX_GHC_LIBDIR"
34− unsetEnv "GHC_ENVIRONMENT"
35− either throwIO return =<< with \db -> do
36− setEnv "TEST_DATABASE_URL" (unpack (toConnectionString db))
37− bracket (either (error . show) return =<< acquire (toConnectionString db)) release \conn -> do
38− flip run conn do
39− sql "create table author ( author_id serial primary key, name text not null, url text )"
40− sql "create table project ( author_id int not null references author (author_id), name text not null )"
41−
42− sql "insert into author ( name, url ) values ( 'Ollie', 'https://ocharles.org.uk' )"
43− sql "insert into author ( name, url ) values ( 'Bryan O''Sullivan', null )"
44− sql "insert into author ( name, url ) values ( 'Emily Pillmore', 'https://cohomolo.gy' )"
45− sql "insert into project ( author_id, name ) values ( 1, 'rel8' )"
46− sql "insert into project ( author_id, name ) values ( 2, 'aeson' )"
47− sql "insert into project ( author_id, name ) values ( 2, 'text' )"
48−
49− doctest (args nixGhcLibdir)
50−
51− where
52− args nixGhcLibdir =
53− flags ++ pkgs ++ foldMap (\x -> ["-package-db" <> x <> "/package.conf.d"]) nixGhcLibdir ++ 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+80−55
@@ -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
@@ -35,36 +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
4655 Rel8.Expr.Text
4756 Rel8.Expr.Time
57+ Rel8.Tabulate
58+
4859 other-modules:
4960 Rel8.Aggregate
5061
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+
5172 Rel8.Expr
5273 Rel8.Expr.Aggregate
5374 Rel8.Expr.Array
5475 Rel8.Expr.Bool
76+ Rel8.Expr.Default
5577 Rel8.Expr.Eq
5678 Rel8.Expr.Function
5779 Rel8.Expr.Null
58− Rel8.Expr.Num
5980 Rel8.Expr.Opaleye
6081 Rel8.Expr.Ord
6182 Rel8.Expr.Order
83+ Rel8.Expr.Sequence
6284 Rel8.Expr.Serialize
85+ Rel8.Expr.Window
6386
6487 Rel8.FCF
6588
66− Rel8.Kind.Labels
67− Rel8.Kind.Necessity
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
68101
69102 Rel8.Order
70103
@@ -73,29 +106,26 @@ library
73106 Rel8.Query.Distinct
74107 Rel8.Query.Each
75108 Rel8.Query.Either
109+ Rel8.Query.Evaluate
76110 Rel8.Query.Exists
77111 Rel8.Query.Filter
112+ Rel8.Query.Indexed
78113 Rel8.Query.Limit
79114 Rel8.Query.List
80115 Rel8.Query.Maybe
81116 Rel8.Query.Null
82117 Rel8.Query.Opaleye
83− Rel8.Query.Optimize
84118 Rel8.Query.Order
119+ Rel8.Query.Rebind
85120 Rel8.Query.Set
86121 Rel8.Query.SQL
87122 Rel8.Query.These
88123 Rel8.Query.Values
124+ Rel8.Query.Window
89125
90− Rel8.Schema.Column
91− Rel8.Schema.Context
92− Rel8.Schema.Context.Identity
93− Rel8.Schema.Context.Label
94126 Rel8.Schema.Context.Nullify
95127 Rel8.Schema.Dict
96128 Rel8.Schema.Field
97− Rel8.Schema.Generic
98− Rel8.Schema.Generic.Test
99129 Rel8.Schema.HTable
100130 Rel8.Schema.HTable.Either
101131 Rel8.Schema.HTable.Identity
@@ -105,55 +135,59 @@ library
105135 Rel8.Schema.HTable.Maybe
106136 Rel8.Schema.HTable.NonEmpty
107137 Rel8.Schema.HTable.Nullify
108− Rel8.Schema.HTable.Pair
109− Rel8.Schema.HTable.Quartet
110− Rel8.Schema.HTable.Quintet
138+ Rel8.Schema.HTable.Product
111139 Rel8.Schema.HTable.These
112− Rel8.Schema.HTable.Trio
113− Rel8.Schema.HTable.Type
114140 Rel8.Schema.HTable.Vectorize
115− Rel8.Schema.Insert
116141 Rel8.Schema.Kind
117142 Rel8.Schema.Name
118− Rel8.Schema.Nullability
143+ Rel8.Schema.Null
144+ Rel8.Schema.Result
119145 Rel8.Schema.Spec
120− Rel8.Schema.Spec.ConstrainDBType
121− Rel8.Schema.Spec.ConstrainType
122146 Rel8.Schema.Table
123147
124148 Rel8.Statement.Delete
125149 Rel8.Statement.Insert
150+ Rel8.Statement.OnConflict
126151 Rel8.Statement.Returning
127152 Rel8.Statement.Select
153+ Rel8.Statement.Set
154+ Rel8.Statement.SQL
128155 Rel8.Statement.Update
156+ Rel8.Statement.Using
129157 Rel8.Statement.View
158+ Rel8.Statement.Where
130159
131160 Rel8.Table
161+ Rel8.Table.ADT
132162 Rel8.Table.Aggregate
133163 Rel8.Table.Alternative
134164 Rel8.Table.Bool
165+ Rel8.Table.Cols
135166 Rel8.Table.Either
136167 Rel8.Table.Eq
137− Rel8.Table.Insert
138− Rel8.Table.Lifted
168+ Rel8.Table.HKD
139169 Rel8.Table.List
140170 Rel8.Table.Maybe
141171 Rel8.Table.Name
142172 Rel8.Table.NonEmpty
173+ Rel8.Table.Null
174+ Rel8.Table.Nullify
143175 Rel8.Table.Opaleye
144176 Rel8.Table.Ord
145177 Rel8.Table.Order
146− Rel8.Table.Recontextualize
178+ Rel8.Table.Projection
179+ Rel8.Table.Rel8able
147180 Rel8.Table.Serialize
148181 Rel8.Table.These
182+ Rel8.Table.Transpose
149183 Rel8.Table.Undefined
150−
151− Rel8.Tabulate
184+ Rel8.Table.Window
152185
153186 Rel8.Type
154187 Rel8.Type.Array
155− Rel8.Type.Array1D
188+ Rel8.Type.Composite
156189 Rel8.Type.Eq
190+ Rel8.Type.Enum
157191 Rel8.Type.Information
158192 Rel8.Type.JSONEncoded
159193 Rel8.Type.JSONBEncoded
@@ -166,8 +200,8 @@ library
166200 Rel8.Type.Sum
167201 Rel8.Type.Tag
168202
169− Rel8.Opaque
170− Rel8.Schema.Structure
203+ Rel8.Window
204+
171205
172206test-suite tests
173207 type: exitcode-stdio-1.0
@@ -177,9 +211,9 @@ test-suite tests
177211 , case-insensitive
178212 , containers
179213 , hasql
180− , hedgehog ^>=1.0.2
181− , lifted-base ^>=0.2.3.12
182− , monad-control ^>=1.0.2.3
214+ , hasql-transaction
215+ , hedgehog ^>= 1.0 || ^>= 1.1
216+ , mmorph
183217 , rel8
184218 , scientific
185219 , tasty
@@ -187,8 +221,12 @@ test-suite tests
187221 , text
188222 , time
189223 , tmp-postgres ^>=1.34.1.0
224+ , transformers
190225 , uuid
191226
227+ other-modules:
228+ Rel8.Generic.Rel8able.Test
229+
192230 main-is: Main.hs
193231 hs-source-dirs: tests
194232 default-language: Haskell2010
@@ -197,16 +235,3 @@ test-suite tests
197235 -Wno-missing-import-lists -Wno-prepositive-qualified-module
198236 -Wno-deprecations -Wno-monomorphism-restriction
199237 -Wno-missing-local-signatures -Wno-implicit-prelude
200−
201−test-suite doctests
202− type: exitcode-stdio-1.0
203− build-depends:
204− base
205− , base-compat
206− , bytestring
207− , doctest
208− , hasql
209− , tmp-postgres
210−
211− main-is: Doctest.hs
212− 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+386−400
@@ -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− -- $guideAggregation
15−
16− -- * Database types
4+ ( -- * Database types
175 -- ** @DBType@
186 DBType(..)
197
@@ -25,6 +13,10 @@ module Rel8
2513 -- **** @ReadShow@
2614 , ReadShow(..)
2715
16+ -- **** Generic
17+ , Composite(..), DBComposite(..), compose, decompose
18+ , Enum(..), DBEnum(..), Enumable
19+
2820 -- *** @TypeInformation@
2921 , TypeInformation(..)
3022 , mapTypeInformation
@@ -34,33 +26,44 @@ module Rel8
3426 , DBSemigroup(..)
3527 , DBMonoid(..)
3628 , DBNum
29+ , DBIntegral
3730 , DBFractional
31+ , DBFloating
3832
3933 -- * Tables and higher-kinded tables
40− , Rel8able
34+ , Rel8able, KRel8able
4135 , Column
42− , Default, Label
36+ , HADT
37+ , HEither
4338 , HMaybe
4439 , HList
4540 , HNonEmpty
41+ , HNull
4642 , HThese
43+ , Lift
4744
48− , Table
45+ , Table(..)
46+ , HTable
47+ , Transposes
4948 , AltTable((<|>:))
50− , EqTable, (==:), (/=:)
51− , OrdTable, ascTable, descTable
49+ , AlternativeTable( emptyTable )
50+ , EqTable(..), (==:), (/=:)
51+ , OrdTable(..), (<:), (<=:), (>:), (>=:), ascTable, descTable, greatest, least
5252 , lit
5353 , bool
5454 , case_
55+ , castTable
5556
5657 -- ** @MaybeTable@
5758 , MaybeTable
58− , maybeTable, nothingTable, justTable
59+ , maybeTable, ($?), nothingTable, justTable
5960 , isNothingTable, isJustTable
61+ , fromMaybeTable
6062 , optional
6163 , catMaybeTable
62− , bindMaybeTable
6364 , traverseMaybeTable
65+ , aggregateMaybeTable
66+ , nameMaybeTable
6467
6568 -- ** @EitherTable@
6669 , EitherTable
@@ -68,8 +71,9 @@ module Rel8
6871 , isLeftTable, isRightTable
6972 , keepLeftTable
7073 , keepRightTable
71− , bindEitherTable
7274 , bitraverseEitherTable
75+ , aggregateEitherTable
76+ , nameEitherTable
7377
7478 -- ** @TheseTable@
7579 , TheseTable
@@ -77,43 +81,99 @@ module Rel8
7781 , isThisTable, isThatTable, isThoseTable
7882 , hasHereTable, hasThereTable
7983 , justHereTable, justThereTable
84+ , alignMaybeTable
8085 , alignBy
8186 , keepHereTable, loseHereTable
8287 , keepThereTable, loseThereTable
8388 , keepThisTable, loseThisTable
8489 , keepThatTable, loseThatTable
8590 , keepThoseTable, loseThoseTable
86− , bindTheseTable
8791 , bitraverseTheseTable
92+ , aggregateTheseTable
93+ , nameTheseTable
8894
8995 -- ** @ListTable@
9096 , ListTable
97+ , listTable, ($*)
98+ , nameListTable
9199 , many
100+ , manyExpr
101+ , catListTable
102+ , catList
92103
93104 -- ** @NonEmptyTable@
94105 , NonEmptyTable
106+ , nonEmptyTable, ($+)
107+ , nameNonEmptyTable
95108 , 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
96151
97152 -- ** Table schemas
98153 , TableSchema(..)
99154 , Name
100155 , namesFromLabels
156+ , namesFromLabelsWith
101157
102158 -- * Expressions
103159 , Expr
104160 , Sql
105161 , litExpr
106162 , unsafeCastExpr
163+ , unsafeLiteral
107164
108165 -- ** @null@
166+ , NotNull
167+ , Nullable
168+ , Homonullable
109169 , null
110170 , nullify
111171 , nullable
112172 , isNull
113173 , isNonNull
114− , mapNullable
115− , liftOpNullable
116− , catNullable
174+ , mapNull
175+ , liftOpNull
176+ , catNull
117177 , coalesce
118178
119179 -- ** Boolean operations
@@ -124,6 +184,7 @@ module Rel8
124184 , (==.), (/=.), (==?), (/=?)
125185 , in_
126186 , boolExpr, caseExpr
187+ , like, ilike
127188
128189 -- ** Ordering
129190 , DBOrd
@@ -141,6 +202,13 @@ module Rel8
141202 , Query
142203 , showQuery
143204
205+ -- ** Projection
206+ , Projection
207+ , Projectable( project )
208+ , Biprojectable( biproject )
209+ , Projecting
210+ , Field
211+
144212 -- ** Selecting rows
145213 , Selects
146214 , each
@@ -149,8 +217,8 @@ module Rel8
149217 -- ** Filtering
150218 , filter
151219 , where_
152− , whereExists
153− , whereNotExists
220+ , present
221+ , absent
154222 , distinct
155223 , distinctOn
156224 , distinctOnBy
@@ -180,13 +248,16 @@ module Rel8
180248
181249 -- ** Aggregation
182250 , Aggregate
251+ , Aggregates
183252 , aggregate
184− , listAgg
185− , nonEmptyAgg
253+ , countRows
186254 , groupBy
255+ , listAgg, listAggExpr
256+ , mode
257+ , nonEmptyAgg, nonEmptyAggExpr
187258 , DBMax, max
188259 , DBMin, min
189− , DBSum, sum
260+ , DBSum, sum, sumWhere, avg
190261 , DBString, stringAgg
191262 , count
192263 , countStar
@@ -203,40 +274,71 @@ module Rel8
203274 , nullsFirst
204275 , nullsLast
205276
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+
206303 -- * IO
207304 , Serializable
305+ , ToExprs
306+ , Result
208307
209308 -- * Running statements
309+ -- $running
310+
210311 -- ** @SELECT@
211312 , select
212313
213314 -- ** @INSERT@
214315 , Insert(..)
215316 , OnConflict(..)
317+ , Upsert(..)
216318 , insert
217− , toInsert
218− , toInsertDefaults
319+ , unsafeDefault
320+ , showInsert
219321
220322 -- ** @DELETE@
221323 , Delete(..)
222324 , delete
325+ , showDelete
223326
224327 -- ** @UPDATE@
225− , update
226328 , Update(..)
329+ , update
330+ , showUpdate
227331
228332 -- ** @.. RETURNING@
229333 , Returning(..)
230334
231− -- * TODO
232− -- TODO
233− -- These need organizing, but are reachable from Rel8's documentation so we
234− -- do need to export and document them.
235− , Nullabilizes
236− , HTable
237− , Labelable
238− , Context
239− , IsMaybe
335+ -- ** @CREATE VIEW@
336+ , createView
337+ , createOrReplaceView
338+
339+ -- ** Sequences
340+ , nextval
341+ , evaluate
240342 ) where
241343
242344-- base
@@ -244,64 +346,94 @@ import Prelude ()
244346
245347-- rel8
246348import 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
247358import Rel8.Expr
248359import Rel8.Expr.Aggregate
249360import Rel8.Expr.Bool
361+import Rel8.Expr.Default
250362import Rel8.Expr.Eq
251363import Rel8.Expr.Function
252364import Rel8.Expr.Null
365+import Rel8.Expr.Opaleye (unsafeCastExpr, unsafeLiteral)
253366import Rel8.Expr.Ord
254367import Rel8.Expr.Order
255368import 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 )
256373import Rel8.Order
257374import Rel8.Query
258375import Rel8.Query.Aggregate
259376import Rel8.Query.Distinct
260377import Rel8.Query.Each
261378import Rel8.Query.Either
379+import Rel8.Query.Evaluate
262380import Rel8.Query.Exists
263381import Rel8.Query.Filter
382+import Rel8.Query.Indexed
264383import Rel8.Query.Limit
265384import Rel8.Query.List
266385import Rel8.Query.Maybe
267386import Rel8.Query.Null
268387import Rel8.Query.Order
388+import Rel8.Query.Rebind
269389import Rel8.Query.SQL (showQuery)
270390import Rel8.Query.Set
271391import Rel8.Query.These
272392import Rel8.Query.Values
273−import Rel8.Schema.Column
274−import Rel8.Schema.Context.Label
275−import Rel8.Schema.Generic
393+import Rel8.Query.Window
394+import Rel8.Schema.Field
276395import Rel8.Schema.HTable
277396import Rel8.Schema.Name
278−import Rel8.Schema.Nullability
397+import Rel8.Schema.Null hiding ( nullable )
398+import Rel8.Schema.Result ( Result )
279399import Rel8.Schema.Table
280400import Rel8.Statement.Delete
281401import Rel8.Statement.Insert
402+import Rel8.Statement.OnConflict
282403import Rel8.Statement.Returning
283404import Rel8.Statement.Select
405+import Rel8.Statement.SQL
284406import Rel8.Statement.Update
407+import Rel8.Statement.View
285408import Rel8.Table
409+import Rel8.Table.ADT
286410import Rel8.Table.Aggregate
287411import Rel8.Table.Alternative
288412import Rel8.Table.Bool
289413import Rel8.Table.Either
290414import Rel8.Table.Eq
291−import Rel8.Table.Insert
415+import Rel8.Table.HKD
292416import Rel8.Table.List
293417import Rel8.Table.Maybe
294418import Rel8.Table.Name
295419import Rel8.Table.NonEmpty
420+import Rel8.Table.Null
421+import Rel8.Table.Opaleye ( castTable )
296422import Rel8.Table.Ord
297423import Rel8.Table.Order
424+import Rel8.Table.Projection
425+import Rel8.Table.Rel8able ()
298426import Rel8.Table.Serialize
299427import Rel8.Table.These
428+import Rel8.Table.Transpose
429+import Rel8.Table.Window
300430import Rel8.Type
431+import Rel8.Type.Composite
301432import Rel8.Type.Eq
433+import Rel8.Type.Enum
302434import Rel8.Type.Information
303−import Rel8.Type.JSONEncoded
304435import Rel8.Type.JSONBEncoded
436+import Rel8.Type.JSONEncoded
305437import Rel8.Type.Monoid
306438import Rel8.Type.Num
307439import Rel8.Type.Ord
@@ -309,362 +441,216 @@ import Rel8.Type.ReadShow
309441import Rel8.Type.Semigroup
310442import Rel8.Type.String
311443import Rel8.Type.Sum
312−import Rel8.Expr.Opaleye (unsafeCastExpr)
313−
314−
315−-- $setup
316−--
317−-- In this section, we'll take a look at using Rel8 to work with a small
318−-- database for Haskell packages. We'll take a look at idiomatic usage of Rel8,
319−-- mapping tables to Haskell, and then look at writing some simple queries.
320−--
321−-- The documentation in this library uses the following language extensions:
322−--
323−-- >>> :set -XBlockArguments
324−-- >>> :set -XDeriveAnyClass
325−-- >>> :set -XDeriveGeneric
326−-- >>> :set -XDerivingStrategies
327−-- >>> :set -XDerivingVia
328−-- >>> :set -XDuplicateRecordFields
329−-- >>> :set -XGeneralizedNewtypeDeriving
330−-- >>> :set -XOverloadedStrings
331−-- >>> :set -XStandaloneDeriving
332−-- >>> :set -XTypeApplications
333−-- >>> :set -XTypeFamilies
334−--
335−-- Before we start writing any Haskell, let's take a look at the schema we'll
336−-- work with.
337−--
338−-- > author: project:
339−-- >
340−-- > Column │ Type │ Nullable Column │ Type │ Nullable
341−-- > ═══════════╪═════════╪══════════ ═══════════╪═════════╪══════════
342−-- > author_id │ integer │ not null author_id │ integer │ not null
343−-- > name │ text │ not null name │ text │ not null
344−-- > url │ text │
345−--
346−-- Our schema consists of two tables - @author@ and @project@. A @project@
347−-- always has an @author@, but not all @author@s have projects. Each @author@
348−-- has a name and (maybe) an associated website, and each project has a name.
349−--
350−-- Now that we've seen our schema, we can begin writing a mapping in Rel8. The
351−-- idiomatic way to map a table is to use a record that is parameterised what
352−-- Rel8 calls an /interpretation functor/, and to define each field with
353−-- 'Column'. For this type to be usable with Rel8 we need it to be an instance
354−-- of 'HigherKindedTable', which can be derived with a combination of
355−-- @DeriveAnyClass@ and @DeriveGeneric@.
356−--
357−-- Following these steps for @author@, we have:
358−--
359−-- > data Author f = Author
360−-- > { authorId :: Column f Int64
361−-- > , name :: Column f Text
362−-- > , url :: Column f (Maybe Text)
363−-- > } deriving (Generic, HigherKindedTable)
364−--
365−-- This is a perfectly reasonable definition, but cautious readers might notice
366−-- a problem - in particular, with the type of the @authorId@ field. While
367−-- @Int64@ is correct, it's not the best type. If we had other identifier types
368−-- in our project, it would be too easy to accidentally mix them up and create
369−-- nonsensical joins. As Haskell programmers, we often solve this problem by
370−-- creating @newtype@ wrappers, and we can also use this technique with Rel8:
371−--
372−-- >>> :{
373−-- newtype AuthorId = AuthorId { toInt64 :: Int64 }
374−-- deriving newtype (DBEq, DBType, Eq, Show)
375−-- :}
376−--
377−-- Now we can write our final schema mapping. First, the @author@ table:
378−--
379−-- >>> :{
380−-- data Author f = Author
381−-- { authorId :: Column f AuthorId
382−-- , authorName :: Column f Text
383−-- , authorUrl :: Column f (Maybe Text)
384−-- }
385−-- deriving stock Generic
386−-- deriving anyclass HigherKindedTable
387−-- :}
388−--
389−-- And similarly, the @project@ table:
390−--
391−-- >>> :{
392−-- data Project f = Project
393−-- { projectAuthorId :: Column f AuthorId
394−-- , projectName :: Column f Text
395−-- }
396−-- deriving stock Generic
397−-- deriving anyclass HigherKindedTable
398−-- :}
399−--
400−-- To show query results in this documentation, we'll also need @Show@
401−-- instances: Unfortunately these definitions look a bit scary, but they are
402−-- essentially just @deriving (Show)@:
403−--
404−-- >>> deriving stock instance f ~ Identity => Show (Author f)
405−-- >>> deriving stock instance f ~ Identity => Show (Project f)
406−--
407−-- These data types describe the structural mapping of the tables, but we also
408−-- need to specify a 'TableSchema' for each table. A @TableSchema@ contains the
409−-- name of the table and the name of all columns in the table, which will
410−-- ultimately allow us to @SELECT@ and @INSERT@ rows for these tables.
411−--
412−-- To define a @TableSchema@, we just need to fill construct appropriate
413−-- @TableSchema@ values. When it comes to the @tableColumns@ field, we
414−-- construct values of our data types above, and set each field to the name of
415−-- the column that it maps to:
416−--
417−-- First, @authorSchema@ describes the column names of the @author@ table when
418−-- associated with the @Author@ type:
419−--
420−-- >>> :{
421−-- authorSchema :: TableSchema (Author ColumnSchema)
422−-- authorSchema = TableSchema
423−-- { tableName = "author"
424−-- , tableSchema = Nothing
425−-- , tableColumns = Author
426−-- { authorId = "author_id"
427−-- , authorName = "name"
428−-- , authorUrl = "url"
429−-- }
430−-- }
431−-- :}
432−--
433−-- And likewise for @project@ and @Project@:
434−--
435−-- >>> :{
436−-- projectSchema :: TableSchema (Project ColumnSchema)
437−-- projectSchema = TableSchema
438−-- { tableName = "project"
439−-- , tableSchema = Nothing
440−-- , tableColumns = Project
441−-- { projectAuthorId = "author_id"
442−-- , projectName = "name"
443−-- }
444−-- }
445−-- :}
446−--
447−-- Aside: you might be wondering why this information isn't in the definitions
448−-- of @Author@ and @Project@ above. Rel8 decouples @TableSchema@ from the data
449−-- types themselves, as not all tables you define will necessarily have a
450−-- schema. For example, Rel8 allows you to define helper types to simplify the
451−-- types of queries - these tables only exist at query time, but there is no
452−-- corresponding base table. We'll see more on this idea later!
453−--
454−-- With these table definitions, we can now start writing some queries! To
455−-- actually run a query, we'll need a database connection. Rel8 uses the
456−-- @hasql@ library, and for this documentation we'll get the connection string
457−-- from the @$TEST_DATABASE_URL@ environment variable.
458−--
459−-- >>> connectionString <- System.Environment.getEnv "TEST_DATABASE_URL"
460−-- >>> Right c <- Hasql.Connection.acquire (Data.ByteString.Char8.pack connectionString)
461−-- >>> Control.Monad.void $ Hasql.Session.run (Hasql.Session.sql "BEGIN") c
462−
463−-- $guideQueries
464−--
465−-- First, we'll take a look at @SELECT@ statements - usually the bulk of most
466−-- database heavy applications.
467−--
468−-- In Rel8, @SELECT@ statements are built using the 'Query' monad. You can
469−-- think of this monad like the ordinary @[]@ (List) monad - but this isn't
470−-- required knowledge.
471−--
472−-- To start, we'll look at one of the simplest queries possible - a basic
473−-- @SELECT * FROM@ statement. To select all rows from a table, we use 'each',
474−-- and supply a 'TableSchema'. So to select all @project@ rows, we can write:
475−--
476−-- >>> :t each projectSchema
477−-- each projectSchema :: Query (Project Expr)
478−--
479−-- Notice that @each@ gives us a @Query@ that yields @Project Expr@ rows. To
480−-- see what this means, let's have a look at a single field of a
481−-- @Project Expr@:
482−--
483−-- >>> let aProjectExpr = undefined :: Project Expr
484−-- >>> :t projectAuthorId aProjectExpr
485−-- projectAuthorId aProjectExpr :: Expr AuthorId
486−--
487−-- Recall we defined @projectAuthorId@ as @Column f AuthorId@. Now we have @f@
488−-- is @Expr@, and @Column Expr AuthorId@ reduces to @Expr AuthorId@. We'll see
489−-- more about @Expr@ soon, but you can think of @Expr a@ as "SQL expressions of
490−-- type @a@".
491−--
492−-- To execute this @Query@, we pass it to 'select':
493−--
494−-- >>> :t select c (each projectSchema)
495−-- select c (each projectSchema) :: MonadIO m => m [Project Identity]
496−--
497−-- When we @select@ things containing @Expr@s, Rel8 builds a new response table
498−-- with the @Identity@ interpretation. This means you'll get back plain Haskell
499−-- values. Studying @projectAuthorId@ again, we have:
500−--
501−-- >>> let aProjectIdentity = undefined :: Project Identity
502−-- >>> :t projectAuthorId aProjectIdentity
503−-- projectAuthorId aProjectIdentity :: AuthorId
504−--
505−-- Here @Column Identity AuthorId@ reduces to just @AuthorId@, with no
506−-- wrappping type at all.
507−--
508−-- Putting this all together, we can run our first query:
509−--
510−-- >>> select c (each projectSchema) >>= mapM_ print
511−-- Project {projectAuthorId = 1, projectName = "rel8"}
512−-- Project {projectAuthorId = 2, projectName = "aeson"}
513−-- Project {projectAuthorId = 2, projectName = "text"}
514−--
515−-- Cool!
516−--
517−-- We now know that 'each' is the equivalent of a @SELECT *@ query, but
518−-- sometimes we're only interested in a subset of the columns of a table. To
519−-- restrict the returned columns, we can specify a projection by using 'Query's
520−-- @Functor@ instance:
521−--
522−-- >>> select c $ projectName <$> each projectSchema
523−-- ["rel8","aeson","text"]
524−
525−-- $guideJoins
526−--
527−-- Another common operation in relational databases is to take the @JOIN@ of
528−-- multiple tables. Rel8 doesn't have a specific join operation, but we can
529−-- recover the functionality of a join by selecting all rows of two tables, and
530−-- then using 'where_' to filter them.
531−--
532−-- To see how this works, first let's look at taking the product of two tables.
533−-- We can do this by simply calling 'each' twice, and then returning a tuple of
534−-- their results.
535−--
536−-- >>> :{
537−-- mapM_ print =<< select c do
538−-- author <- each authorSchema
539−-- project <- each projectSchema
540−-- return (projectName project, authorName author)
541−-- :}
542−-- ("rel8","Ollie")
543−-- ("rel8","Bryan O'Sullivan")
544−-- ("rel8","Emily Pillmore")
545−-- ("aeson","Ollie")
546−-- ("aeson","Bryan O'Sullivan")
547−-- ("aeson","Emily Pillmore")
548−-- ("text","Ollie")
549−-- ("text","Bryan O'Sullivan")
550−-- ("text","Emily Pillmore")
551−--
552−-- This isn't quite right, though, as we have ended up pairing up the wrong
553−-- projects and authors. To fix this, we can use 'where_' to restrict the
554−-- returned rows. We could write:
555−--
556−-- > select c $ do
557−-- > author <- each authorSchema
558−-- > project <- each projectSchema
559−-- > where_ $ projectAuthorId project ==. authorId author
560−-- > return (project, author)
561−--
562−-- but doing this every time you need a join can obscure the meaning of the
563−-- query you're writing. A good practice is to introduce specialised functions
564−-- for the particular joins in your database. In our case, this would be:
565−--
566−-- >>> :{
567−-- projectsForAuthor :: Author Expr -> Query (Project Expr)
568−-- projectsForAuthor a = each projectSchema >>= filter \p ->
569−-- projectAuthorId p ==. authorId a
570−-- :}
571−--
572−-- Our final query is then:
573−--
574−-- >>> :{
575−-- mapM_ print =<< select c do
576−-- author <- each authorSchema
577−-- project <- projectsForAuthor author
578−-- return (projectName project, authorName author)
579−-- :}
580−-- ("rel8","Ollie")
581−-- ("aeson","Bryan O'Sullivan")
582−-- ("text","Bryan O'Sullivan")
583−--
584−-- == @LEFT JOIN@s
585−--
586−-- Rel8 is also capable of performing @LEFT JOIN@s. To perform @LEFT JOIN@s, we
587−-- follow the same approach as before, but use the 'optional' query transformer
588−-- to allow for the possibility of the join to fail.
589−--
590−-- In our test database, we can see that there's another author who we haven't
591−-- seen yet:
592−--
593−-- >>> select c $ authorName <$> each authorSchema
594−-- ["Ollie","Bryan O'Sullivan","Emily Pillmore"]
595−--
596−-- Emily wasn't returned in our earlier query because - in our database - she
597−-- doesn't have any registered projects. We can account for this partiality in
598−-- our original query by wrapping the @projectsForAuthor@ call with 'optional':
599−--
600−-- >>> :{
601−-- mapM_ print =<< select c do
602−-- author <- each authorSchema
603−-- mproject <- optional $ projectsForAuthor author
604−-- return (authorName author, projectName <$> mproject)
605−-- :}
606−-- ("Ollie",Just "rel8")
607−-- ("Bryan O'Sullivan",Just "aeson")
608−-- ("Bryan O'Sullivan",Just "text")
609−-- ("Emily Pillmore",Nothing)
444+import Rel8.Window
610445
611−-- $guideAggregation
612−--
613−-- Aggregations are operations like @sum@ and @count@ - operations that reduce
614−-- multiple rows to single values. To perform aggregations in Rel8, we can use
615−-- the 'aggregate' function, which takes a 'Query' of aggregated expressions,
616−-- runs the aggregation, and returns aggregated rows.
617−--
618−-- To start, let's look at a simple aggregation that tells us how many projects
619−-- exist:
620−--
621−-- >>> error "TODO"
622−--
623−-- Rel8 is also capable of aggregating multiple rows into a single row by
624−-- concatenating all rows as a list. This aggregation allows us to break free
625−-- of the row-orientated nature of SQL and write queries that return tree-like
626−-- structures. Earlier we saw an example of returning authors with their
627−-- projects, but the query didn't do a great job of describing the one-to-many
628−-- relationship between authors and their projects.
629−--
630−-- Let's look again at a query that returns authors and their projects, and
631−-- focus on the /type/ of that query.
632−--
633−-- >>> :{
634−-- projectsForAuthor a = each projectSchema >>= filter \p ->
635−-- projectAuthorId p ==. authorId a
636−-- :}
637−--
638−-- >>> :{
639−-- let authorsAndProjects = do
640−-- author <- each authorSchema
641−-- project <- projectsForAuthor author
642−-- return (author, project)
643−-- where
644−-- :}
446+
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.
452+
453+-- $adts
454+-- Algebraic data types can be modelled between Haskell and SQL.
645455--
646−-- >>> :t select c authorsAndProjects
647−-- select c authorsAndProjects
648−-- :: MonadIO m => m [(Author Identity, Project Identity)]
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.
649459--
650−-- Our query gives us a single list of pairs of authors and projects. However,
651−-- with our domain knowledge of the schema, this isn't a great type - what we'd
652−-- rather have is a list of pairs of authors and /lists/ of projects. That is,
653−-- what we'd like is:
460+-- The documentation in this section will assume a set of database types like this:
654461--
655−-- > [(Author Identity, [Project Identity])]
462+-- @
463+-- data Thing f = ThingEmployer (Employer f) | ThingPotato (Potato f) | Nullary
464+-- deriving stock Generic
656465--
657−-- This would be a much better type! Rel8 can produce a query with this type by
658−-- simply wrapping the call to @projectsForAuthor@ with either 'some' or
659−-- 'many'. Here we'll use 'many', which allows for the possibility of an author
660−-- to have no projects:
466+-- data Employer f = Employer { employerId :: f Int32, employerName :: f Text}
467+-- deriving stock Generic
468+-- deriving anyclass Rel8able
661469--
662−-- >>> :{
663−-- mapM_ print =<< select c do
664−-- author <- each authorSchema
665−-- projectNames <- many $ projectName <$> projectsForAuthor author
666−-- 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+-- ]
667586-- :}
668−-- ("Ollie",["rel8"])
669−-- ("Bryan O'Sullivan",["aeson","text"])
670−-- ("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+45−150
@@ -1,188 +1,83 @@
11{-# language DataKinds #-}
2−{-# language DerivingVia #-}
32{-# language FlexibleContexts #-}
43{-# language FlexibleInstances #-}
5−{-# language GADTs #-}
6−{-# language GeneralizedNewtypeDeriving #-}
74{-# language MultiParamTypeClasses #-}
8−{-# language NamedFieldPuns #-}
5+{-# language RankNTypes #-}
96{-# language StandaloneKindSignatures #-}
107{-# language TypeFamilies #-}
118{-# language UndecidableInstances #-}
12−{-# language UndecidableSuperClasses #-}
139
1410module Rel8.Aggregate
15− ( Aggregate(..)
16− , Aggregator(..), unsafeMakeAggregate
11+ ( Aggregate(..), zipOutputs
12+ , unsafeMakeAggregate
1713 , Aggregates
18− , Col( Aggregation )
1914 )
2015where
2116
2217-- base
23−import Control.Applicative ( empty )
24−import Data.Foldable ( fold )
25−import Data.Functor.Const ( Const( Const ), getConst )
26−import Data.Functor.Identity ( Identity )
18+import Control.Applicative ( liftA2 )
19+import Data.Functor.Identity ( Identity( Identity ) )
2720import Data.Kind ( Constraint, Type )
28−import Data.Monoid ( First( First ), getFirst )
2921import Prelude
3022
23+-- profunctors
24+import Data.Profunctor ( dimap )
25+
3126-- opaleye
32−import qualified Opaleye.Internal.Aggregate as Opaleye
27+import qualified Opaleye.Aggregate as Opaleye
3328import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
34−import qualified Opaleye.Internal.PackMap as Opaleye
29+import qualified Opaleye.Internal.Column as Opaleye
3530
3631-- rel8
37−import Rel8.Expr ( Expr, Col(..) )
38−import Rel8.Expr.Opaleye ( fromPrimExpr, toPrimExpr )
39−import Rel8.Opaque ( Opaque, Opaque1 )
40−import Rel8.Schema.Context ( Interpretation(..) )
41−import Rel8.Schema.Context.Label ( Labelable(..) )
42−import Rel8.Schema.Context.Nullify
43− ( Nullifiable, encodeTag, decodeTag, nullifier, unnullifier
44− , runTag, unnull
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
4540 )
46−import Rel8.Schema.HTable ( hfield, htabulate, htabulateA, hspecs )
47−import Rel8.Schema.Name ( Name )
48−import Rel8.Schema.Nullability ( Sql )
49−import Rel8.Schema.Spec ( Spec( Spec ), SSpec(..) )
50−import Rel8.Table ( Table, Columns, Context, fromColumns, toColumns )
51−import Rel8.Table.Recontextualize ( Recontextualize )
41+import Rel8.Table.Transpose ( Transposes )
5242import Rel8.Type ( DBType )
5343
54−-- semigroupoids
55−import Data.Functor.Apply ( Apply, WrappedApplicative(..) )
56−
57−
58−-- | An @Aggregate a@ describes how to aggregate @Table@s of type @a@. You can
59−-- unpack an @Aggregate@ back to @a@ by running it with 'aggregate'. As
60−-- @Aggregate@ is almost an 'Applicative' functor - but there is no 'pure'
61−-- operation. This means 'Aggregate' is an instance of 'Apply', and you can
62−-- combine @Aggregate@s using the @<.>@ combinator.
63−type Aggregate :: Type -> Type
64−newtype Aggregate a = Aggregate (Opaleye.Aggregator () a)
65− deriving newtype Functor
66− deriving Apply via (WrappedApplicative (Opaleye.Aggregator ()))
67−
6844
69−instance Interpretation Aggregate where
70− data Col Aggregate _spec where
71− Aggregation :: ()
72− => Aggregate (Expr a)
73− -> Col Aggregate ('Spec labels necessity db a)
45+-- | 'Aggregate' is a special context used by 'Rel8.aggregate'.
46+type Aggregate :: K.Context
47+newtype Aggregate a = Aggregate (Opaleye.Aggregator () (Expr a))
7448
7549
76−instance Table Expr a => Table Aggregate (Aggregate a) where
77− type Columns (Aggregate a) = Columns a
50+instance Sql DBType a => Table Aggregate (Aggregate a) where
51+ type Columns (Aggregate a) = HIdentity a
7852 type Context (Aggregate a) = Aggregate
53+ type FromExprs (Aggregate a) = a
54+ type Transpose to (Aggregate a) = to a
7955
80− toColumns a = htabulate $ \field -> case hfield hspecs field of
81− SSpec {} -> Aggregation $ unDB . (`hfield` field) . toColumns <$> a
82− fromColumns as = fmap fromColumns $ htabulateA $ \field ->
83− case hfield as field of
84− Aggregation a -> DB <$> a
85−
86−
87−instance Sql DBType a =>
88− Recontextualize Aggregate Aggregate (Aggregate (Expr a)) (Aggregate (Expr a))
89−
90−
91−instance Sql DBType a =>
92− Recontextualize Aggregate Expr (Aggregate (Expr a)) (Expr a)
93−
94−
95−instance Sql DBType a =>
96− Recontextualize Aggregate Identity (Aggregate (Expr a)) (Identity a)
97−
98−
99−instance Sql DBType a =>
100− Recontextualize Aggregate Name (Aggregate (Expr a)) (Name a)
101−
102−
103−instance Sql DBType a =>
104− Recontextualize Expr Aggregate (Expr a) (Aggregate (Expr a))
105−
56+ toColumns = HIdentity
57+ fromColumns (HIdentity a) = a
58+ toResult = HIdentity . Identity
59+ fromResult (HIdentity (Identity a)) = a
10660
107−instance Sql DBType a =>
108− Recontextualize Identity Aggregate (Identity a) (Aggregate (Expr a))
10961
110−
111−instance Sql DBType a =>
112− Recontextualize Name Aggregate (Name a) (Aggregate (Expr a))
113−
114−
115−instance Labelable Aggregate where
116− labeler (Aggregation aggregate) = Aggregation aggregate
117− unlabeler (Aggregation aggregate) = Aggregation aggregate
118−
119−
120−instance Nullifiable Aggregate where
121− encodeTag = Aggregation . groupByExpr
122− where
123− groupByExpr = unsafeMakeAggregate toPrimExpr fromPrimExpr Nothing
124− decodeTag (Aggregation aggregate) = fold $ undoGroupBy aggregate
125− where
126− undoGroupBy = getFirst . foldInputs go
127− where
128− go Nothing = pure . fromPrimExpr
129− go _ = const $ First empty
130−
131− nullifier tag SSpec {nullability} (Aggregation aggregate) = Aggregation $
132− mapInputs (toPrimExpr . runTag nullability tag . fromPrimExpr) $
133− runTag nullability tag <$> aggregate
134−
135− unnullifier _ SSpec {nullability} (Aggregation aggregate) =
136− Aggregation $ unnull nullability <$> aggregate
137−
138− {-# INLINABLE encodeTag #-}
139− {-# INLINABLE decodeTag #-}
140− {-# INLINABLE nullifier #-}
141− {-# INLINABLE unnullifier #-}
142−
143−
144−-- | @Aggregates a b@ means that the columns in @a@ are all 'Aggregate' 'Expr's
145−-- for the columns in @b@.
62+-- | @Aggregates a b@ means that the columns in @a@ are all 'Aggregate's
63+-- for the 'Expr' columns in @b@.
14664type Aggregates :: Type -> Type -> Constraint
147−class Recontextualize Aggregate Expr aggregates exprs => Aggregates aggregates exprs
148−instance Recontextualize Aggregate Expr aggregates exprs => Aggregates aggregates exprs
149−instance {-# OVERLAPPING #-} Aggregates (Opaque1 Aggregate Opaque) (Opaque1 Expr Opaque)
150−
151−
152−foldInputs :: Monoid b
153− => (Maybe Aggregator -> Opaleye.PrimExpr -> b) -> Aggregate a -> b
154−foldInputs f (Aggregate (Opaleye.Aggregator (Opaleye.PackMap agg))) =
155− getConst $ flip agg () $ \(aggregator, a) ->
156− Const $ f (detuplize <$> aggregator) a
157− where
158− detuplize (operation, ordering, distinction) =
159− Aggregator {operation, ordering, distinction}
160−
161−
162−mapInputs :: ()
163− => (Opaleye.PrimExpr -> Opaleye.PrimExpr) -> Aggregate a -> Aggregate a
164−mapInputs transform (Aggregate (Opaleye.Aggregator (Opaleye.PackMap agg))) =
165− Aggregate $ Opaleye.Aggregator $ Opaleye.PackMap $ agg . \f input ->
166− f (fmap transform input)
65+class Transposes Aggregate Expr aggregates exprs => Aggregates aggregates exprs
66+instance Transposes Aggregate Expr aggregates exprs => Aggregates aggregates exprs
16767
16868
169−type Aggregator :: Type
170−data Aggregator = Aggregator
171− { operation :: Opaleye.AggrOp
172− , ordering :: [Opaleye.OrderExpr]
173− , distinction :: Opaleye.AggrDistinct
174− }
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)
17572
17673
177−unsafeMakeAggregate :: ()
178− => (input -> Opaleye.PrimExpr)
179− -> (Opaleye.PrimExpr -> output)
180− -> Maybe Aggregator
181− -> 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
18279 -> Aggregate output
18380unsafeMakeAggregate input output aggregator expr =
184− Aggregate $ Opaleye.Aggregator $ Opaleye.PackMap $ \f _ ->
185− output <$> f (tuplize <$> aggregator, input expr)
186− where
187− tuplize Aggregator {operation, ordering, distinction} =
188− (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+47−75
@@ -2,27 +2,20 @@
22{-# language DerivingStrategies #-}
33{-# language FlexibleContexts #-}
44{-# language FlexibleInstances #-}
5−{-# language GADTs #-}
65{-# language MultiParamTypeClasses #-}
7−{-# language NamedFieldPuns #-}
8−{-# language RoleAnnotations #-}
96{-# language ScopedTypeVariables #-}
107{-# language StandaloneKindSignatures #-}
118{-# language TypeApplications #-}
129{-# language TypeFamilies #-}
1310{-# language UndecidableInstances #-}
14−{-# language UndecidableSuperClasses #-}
1511
1612module Rel8.Expr
1713 ( Expr(..)
18− , Col( DB, unDB )
19− , Encodes
2014 )
2115where
2216
2317-- base
24−import Data.Functor.Identity ( Identity )
25−import Data.Kind ( Constraint, Type )
18+import Data.Functor.Identity ( Identity( Identity ) )
2619import Data.String ( IsString, fromString )
2720import Prelude hiding ( null )
2821
@@ -30,7 +23,8 @@ import Prelude hiding ( null )
3023import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
3124
3225-- rel8
33−import Rel8.Expr.Null ( liftOpNullable, nullify )
26+import Rel8.Expr.Function ( function, nullaryFunction )
27+import Rel8.Expr.Null ( liftOpNull, nullify )
3428import Rel8.Expr.Opaleye
3529 ( castExpr
3630 , fromPrimExpr
@@ -38,52 +32,44 @@ import Rel8.Expr.Opaleye
3832 , zipPrimExprsWith
3933 )
4034import Rel8.Expr.Serialize ( litExpr )
41−import Rel8.Opaque ( Opaque, Opaque1 )
42−import Rel8.Schema.Context ( Interpretation, Col )
43−import Rel8.Schema.Context.Label ( Labelable, labeler, unlabeler )
44−import Rel8.Schema.Context.Nullify
45− ( Nullifiable, encodeTag, decodeTag, nullifier, unnullifier
46− , runTag, unnull
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
4742 )
48−import Rel8.Schema.HTable.Type ( HType( HType ) )
49−import Rel8.Schema.Nullability
50− ( Nullability( Nullable, NonNullable )
51− , Sql, nullabilization
52− )
53−import Rel8.Schema.Spec ( Spec( Spec ), SSpec(..) )
54−import Rel8.Table ( Table, Columns, Context, fromColumns, toColumns )
55−import Rel8.Table.Recontextualize ( Recontextualize )
5643import Rel8.Type ( DBType )
5744import Rel8.Type.Monoid ( DBMonoid, memptyExpr )
58−import Rel8.Type.Num ( DBFractional, DBNum )
45+import Rel8.Type.Num ( DBFloating, DBFractional, DBNum )
5946import Rel8.Type.Semigroup ( DBSemigroup, (<>.) )
6047
6148
6249-- | Typed SQL expressions.
63−type role Expr representational
64−type Expr :: Type -> Type
50+type Expr :: K.Context
6551newtype Expr a = Expr Opaleye.PrimExpr
6652 deriving stock Show
6753
6854
6955instance Sql DBSemigroup a => Semigroup (Expr a) where
70− (<>) = case nullabilization @a of
71− Nullable -> liftOpNullable (<>.)
72− NonNullable -> (<>.)
56+ (<>) = case nullable @a of
57+ Null -> liftOpNull (<>.)
58+ NotNull -> (<>.)
7359 {-# INLINABLE (<>) #-}
7460
7561
7662instance Sql DBMonoid a => Monoid (Expr a) where
77− mempty = case nullabilization @a of
78− Nullable -> nullify memptyExpr
79− NonNullable -> memptyExpr
63+ mempty = case nullable @a of
64+ Null -> nullify memptyExpr
65+ NotNull -> memptyExpr
8066 {-# INLINABLE mempty #-}
8167
8268
8369instance (Sql IsString a, Sql DBType a) => IsString (Expr a) where
84− fromString = litExpr . case nullabilization @a of
85− Nullable -> Just . fromString
86− NonNullable -> fromString
70+ fromString = litExpr . case nullable @a of
71+ Null -> Just . fromString
72+ NotNull -> fromString
8773
8874
8975instance Sql DBNum a => Num (Expr a) where
@@ -106,48 +92,34 @@ instance Sql DBFractional a => Fractional (Expr a) where
10692 castExpr . Expr . Opaleye.ConstExpr . Opaleye.NumericLit . realToFrac
10793
10894
109−instance Interpretation Expr where
110− data Col Expr _spec where
111− DB :: ()
112− => { unDB :: Expr a }
113− -> Col Expr ('Spec labels necessity db a)
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"
114114
115115
116116instance Sql DBType a => Table Expr (Expr a) where
117− type Columns (Expr a) = HType a
117+ type Columns (Expr a) = HIdentity a
118118 type Context (Expr a) = Expr
119+ type FromExprs (Expr a) = a
120+ type Transpose to (Expr a) = to a
119121
120− toColumns a = HType (DB a)
121− fromColumns (HType (DB a)) = a
122−
123−
124−instance Sql DBType a => Recontextualize Expr Expr (Expr a) (Expr a)
125−
126−
127−instance Sql DBType a => Recontextualize Expr Identity (Expr a) (Identity a)
128−
129−
130−instance Sql DBType a => Recontextualize Identity Expr (Identity a) (Expr a)
131−
132−
133−instance Labelable Expr where
134− labeler (DB a) = DB a
135− unlabeler (DB a) = DB a
136−
137−
138−instance Nullifiable Expr where
139− encodeTag = DB
140− decodeTag (DB a) = a
141− nullifier tag SSpec {nullability} (DB a) = DB $ runTag nullability tag a
142− unnullifier _ SSpec {nullability} (DB a) = DB $ unnull nullability a
143−
144− {-# INLINABLE encodeTag #-}
145− {-# INLINABLE decodeTag #-}
146− {-# INLINABLE nullifier #-}
147− {-# INLINABLE unnullifier #-}
148−
149−
150−type Encodes :: Type -> Type -> Constraint
151−class Recontextualize Identity Expr a exprs => Encodes a exprs
152−instance Recontextualize Identity Expr a exprs => Encodes a exprs
153−instance {-# OVERLAPPING #-} Encodes (Opaque1 Identity Opaque) (Opaque1 Expr Opaque)
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+58−87
@@ -1,7 +1,6 @@
11{-# language DataKinds #-}
22{-# language FlexibleContexts #-}
33{-# language ScopedTypeVariables #-}
4−{-# language TypeApplications #-}
54{-# language TypeFamilies #-}
65
76{-# options_ghc -fno-warn-redundant-constraints #-}
@@ -11,10 +10,11 @@ module Rel8.Expr.Aggregate
1110 , and, or
1211 , min, max
1312 , sum, sumWhere
13+ , avg
1414 , stringAgg
1515 , groupByExpr
1616 , listAggExpr, nonEmptyAggExpr
17− , sgroupByExpr
17+ , slistAggExpr, snonEmptyAggExpr
1818 )
1919where
2020
@@ -24,10 +24,12 @@ import Data.List.NonEmpty ( NonEmpty )
2424import Prelude hiding ( and, max, min, null, or, sum )
2525
2626-- opaleye
27−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
2830
2931-- rel8
30−import Rel8.Aggregate ( Aggregate, Aggregator(..), unsafeMakeAggregate )
32+import Rel8.Aggregate ( Aggregate, unsafeMakeAggregate )
3133import Rel8.Expr ( Expr )
3234import Rel8.Expr.Bool ( caseExpr )
3335import Rel8.Expr.Opaleye
@@ -38,9 +40,11 @@ import Rel8.Expr.Opaleye
3840 )
3941import Rel8.Expr.Null ( null )
4042import Rel8.Expr.Serialize ( litExpr )
41−import Rel8.Schema.Nullability ( Nullability, Sql, nullabilization )
42−import Rel8.Type.Array ( fromPrimArray )
43+import Rel8.Schema.Null ( Sql, Unnullify )
44+import Rel8.Type ( DBType, typeInformation )
45+import Rel8.Type.Array ( encodeArrayElement )
4346import Rel8.Type.Eq ( DBEq )
47+import Rel8.Type.Information ( TypeInformation )
4448import Rel8.Type.Num ( DBNum )
4549import Rel8.Type.Ord ( DBMax, DBMin )
4650import Rel8.Type.String ( DBString )
@@ -48,132 +52,99 @@ import Rel8.Type.Sum ( DBSum )
4852
4953
5054-- | Count the occurances of a single column. Corresponds to @COUNT(a)@
51−count :: Expr a -> Aggregate (Expr Int64)
52−count = unsafeMakeAggregate toPrimExpr fromPrimExpr $
53− Just Aggregator
54− { operation = Opaleye.AggrCount
55− , ordering = []
56− , distinction = Opaleye.AggrAll
57− }
58−
55+count :: Expr a -> Aggregate Int64
56+count = unsafeMakeAggregate toPrimExpr fromPrimExpr Opaleye.count
5957
6058-- | Count the number of distinct occurances of a single column. Corresponds to
6159-- @COUNT(DISTINCT a)@
62−countDistinct :: DBEq a => Expr a -> Aggregate (Expr Int64)
60+countDistinct :: Sql DBEq a => Expr a -> Aggregate Int64
6361countDistinct = unsafeMakeAggregate toPrimExpr fromPrimExpr $
64− Just Aggregator
65− { operation = Opaleye.AggrCount
66− , ordering = []
67− , distinction = Opaleye.AggrDistinct
68− }
62+ Opaleye.distinctAggregator Opaleye.count
6963
7064
7165-- | Corresponds to @COUNT(*)@.
72−countStar :: Aggregate (Expr Int64)
66+countStar :: Aggregate Int64
7367countStar = count (litExpr True)
7468
7569
7670-- | A count of the number of times a given expression is @true@.
77−countWhere :: Expr Bool -> Aggregate (Expr Int64)
71+countWhere :: Expr Bool -> Aggregate Int64
7872countWhere condition = count (caseExpr [(condition, litExpr (Just True))] null)
7973
8074
8175-- | Corresponds to @bool_and@.
82−and :: Expr Bool -> Aggregate (Expr Bool)
83−and = unsafeMakeAggregate toPrimExpr fromPrimExpr $
84− Just Aggregator
85− { operation = Opaleye.AggrBoolAnd
86− , ordering = []
87− , distinction = Opaleye.AggrAll
88− }
76+and :: Expr Bool -> Aggregate Bool
77+and = unsafeMakeAggregate toPrimExpr fromPrimExpr Opaleye.boolAnd
8978
9079
9180-- | Corresponds to @bool_or@.
92−or :: Expr Bool -> Aggregate (Expr Bool)
93−or = unsafeMakeAggregate toPrimExpr fromPrimExpr $
94− Just Aggregator
95− { operation = Opaleye.AggrBoolOr
96− , ordering = []
97− , distinction = Opaleye.AggrAll
98− }
81+or :: Expr Bool -> Aggregate Bool
82+or = unsafeMakeAggregate toPrimExpr fromPrimExpr Opaleye.boolOr
9983
10084
10185-- | Produce an aggregation for @Expr a@ using the @max@ function.
102−max :: Sql DBMax a => Expr a -> Aggregate (Expr a)
103−max = unsafeMakeAggregate toPrimExpr fromPrimExpr $
104− Just Aggregator
105− { operation = Opaleye.AggrSum
106− , ordering = []
107− , distinction = Opaleye.AggrAll
108− }
86+max :: Sql DBMax a => Expr a -> Aggregate a
87+max = unsafeMakeAggregate toPrimExpr fromPrimExpr Opaleye.unsafeMax
10988
11089
11190-- | Produce an aggregation for @Expr a@ using the @max@ function.
112−min :: Sql DBMin a => Expr a -> Aggregate (Expr a)
113−min = unsafeMakeAggregate toPrimExpr fromPrimExpr $
114− Just Aggregator
115− { operation = Opaleye.AggrSum
116− , ordering = []
117− , distinction = Opaleye.AggrAll
118− }
91+min :: Sql DBMin a => Expr a -> Aggregate a
92+min = unsafeMakeAggregate toPrimExpr fromPrimExpr Opaleye.unsafeMin
11993
12094-- | Corresponds to @sum@. Note that in SQL, @sum@ is type changing - for
12195-- example the @sum@ of @integer@ returns a @bigint@. Rel8 doesn't support
122−-- this, and will add explicit cast back to the original input type. This can
96+-- this, and will add explicit casts back to the original input type. This can
12397-- lead to overflows, and if you anticipate very large sums, you should upcast
12498-- your input.
125−sum :: Sql DBSum a => Expr a -> Aggregate (Expr a)
126−sum = unsafeMakeAggregate toPrimExpr (castExpr . fromPrimExpr) $
127− Just Aggregator
128− { operation = Opaleye.AggrSum
129− , ordering = []
130− , distinction = Opaleye.AggrAll
131− }
99+sum :: Sql DBSum a => Expr a -> Aggregate a
100+sum = unsafeMakeAggregate toPrimExpr (castExpr . fromPrimExpr) Opaleye.unsafeSum
101+
132102
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
133110
111+-- | Take the sum of all expressions that satisfy a predicate.
134112sumWhere :: (Sql DBNum a, Sql DBSum a)
135− => Expr Bool -> Expr a -> Aggregate (Expr a)
113+ => Expr Bool -> Expr a -> Aggregate a
136114sumWhere condition a = sum (caseExpr [(condition, a)] 0)
137115
138116
139117-- | Corresponds to @string_agg()@.
140118stringAgg :: Sql DBString a
141− => Expr db -> Expr a -> Aggregate (Expr a)
119+ => Expr db -> Expr a -> Aggregate a
142120stringAgg delimiter =
143− unsafeMakeAggregate toPrimExpr (castExpr . fromPrimExpr) $
144− Just Aggregator
145− { operation = Opaleye.AggrStringAggr (toPrimExpr delimiter)
146− , ordering = []
147− , distinction = Opaleye.AggrAll
148− }
121+ unsafeMakeAggregate toPrimExpr (castExpr . fromPrimExpr) (Opaleye.stringAgg (Column (toPrimExpr delimiter)))
149122
150123
151124-- | Aggregate a value by grouping by it.
152−groupByExpr :: Sql DBEq a => Expr a -> Aggregate (Expr a)
153−groupByExpr = sgroupByExpr nullabilization
125+groupByExpr :: Sql DBEq a => Expr a -> Aggregate a
126+groupByExpr = unsafeMakeAggregate toPrimExpr fromPrimExpr Opaleye.groupBy
154127
155128
156−listAggExpr :: Expr a -> Aggregate (Expr [a])
157−listAggExpr = unsafeMakeAggregate toPrimExpr from $ Just
158− Aggregator
159− { operation = Opaleye.AggrArr
160− , ordering = []
161− , distinction = Opaleye.AggrAll
162− }
163− where
164− from = fromPrimExpr . fromPrimArray
129+-- | Collect expressions values as a list.
130+listAggExpr :: Sql DBType a => Expr a -> Aggregate [a]
131+listAggExpr = slistAggExpr typeInformation
165132
166133
167−nonEmptyAggExpr :: Expr a -> Aggregate (Expr (NonEmpty a))
168−nonEmptyAggExpr = unsafeMakeAggregate toPrimExpr from $ Just
169− Aggregator
170− { operation = Opaleye.AggrArr
171− , ordering = []
172− , distinction = Opaleye.AggrAll
173− }
134+-- | Collect expressions values as a non-empty list.
135+nonEmptyAggExpr :: Sql DBType a => Expr a -> Aggregate (NonEmpty a)
136+nonEmptyAggExpr = snonEmptyAggExpr typeInformation
137+
138+
139+slistAggExpr :: ()
140+ => TypeInformation (Unnullify a) -> Expr a -> Aggregate [a]
141+slistAggExpr info = unsafeMakeAggregate to fromPrimExpr Opaleye.arrayAgg
174142 where
175− from = fromPrimExpr . fromPrimArray
143+ to = encodeArrayElement info . toPrimExpr
176144
177145
178−sgroupByExpr :: DBEq db => Nullability db a -> Expr a -> Aggregate (Expr a)
179−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 ( Unnullify, Nullability, Sql )
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. Sql DBType a => [Expr a] -> Expr [a]
47−listOf =
48− fromPrimExpr . array (typeInformation @(Unnullify a)) . 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. Sql DBType a => NonEmpty (Expr a) -> Expr (NonEmpty a)
52−nonEmptyOf =
53− fromPrimExpr . array (typeInformation @(Unnullify a)) . 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+29−60
@@ -1,13 +1,13 @@
11{-# language FlexibleContexts #-}
22{-# language GADTs #-}
3−{-# language LambdaCase #-}
3+{-# language ScopedTypeVariables #-}
4+{-# language TypeApplications #-}
45{-# language ViewPatterns #-}
56
67{-# options_ghc -fno-warn-redundant-constraints #-}
78
89module Rel8.Expr.Eq
9− ( seq, sne
10− , (==.), (/=.)
10+ ( (==.), (/=.)
1111 , (==?), (/=?)
1212 , in_
1313 )
@@ -16,7 +16,7 @@ where
1616-- base
1717import Data.Foldable ( toList )
1818import Data.List.NonEmpty ( nonEmpty )
19−import Prelude hiding ( seq, sin )
19+import Prelude
2020
2121-- opaleye
2222import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
@@ -24,12 +24,9 @@ import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
2424-- rel8
2525import Rel8.Expr ( Expr )
2626import Rel8.Expr.Bool ( (&&.), (||.), false, or_, coalesce )
27−import Rel8.Expr.Null ( isNull, unsafeLiftOpNullable )
27+import Rel8.Expr.Null ( isNull, unsafeLiftOpNull )
2828import Rel8.Expr.Opaleye ( fromPrimExpr, toPrimExpr, zipPrimExprsWith )
29−import Rel8.Schema.Nullability
30− ( Nullability( NonNullable, Nullable )
31− , Sql, nullabilization
32− )
29+import Rel8.Schema.Null ( Nullity( NotNull, Null ), Sql, nullable )
3330import Rel8.Type.Eq ( DBEq )
3431
3532
@@ -41,40 +38,18 @@ ne :: DBEq a => Expr a -> Expr a -> Expr Bool
4138ne = zipPrimExprsWith (Opaleye.BinExpr (Opaleye.:<>))
4239
4340
44−seq :: DBEq db => Nullability db a -> Expr a -> Expr a -> Expr Bool
45−seq = \case
46− Nullable -> \ma mb -> isNull ma &&. isNull mb ||. ma ==? mb
47− NonNullable -> eq
48−
49−
50−sne :: DBEq db => Nullability db a -> Expr a -> Expr a -> Expr Bool
51−sne = \case
52− Nullable -> \ma mb -> isNull ma `ne` isNull mb ||. ma /=? mb
53− NonNullable -> ne
54−
55−
56−sin :: (DBEq db, Foldable f)
57− => Nullability db a -> Expr a -> f (Expr a) -> Expr Bool
58−sin nullability a (toList -> as) = case nullability of
59− Nullable -> or_ $ map (seq Nullable a) as
60− NonNullable -> case nonEmpty as of
61− Nothing -> false
62− Just xs ->
63− fromPrimExpr $
64− Opaleye.BinExpr Opaleye.OpIn
65− (toPrimExpr a)
66− (Opaleye.ListExpr (toPrimExpr <$> xs))
67−
68−
6941-- | Compare two expressions for equality.
7042--
7143-- This corresponds to the SQL @IS NOT DISTINCT FROM@ operator, and will equate
7244-- @null@ values as @true@. This differs from @=@ which would return @null@.
7345-- This operator matches Haskell's '==' operator. For an operator identical to
7446-- SQL @=@, see '==?'.
75−(==.) :: Sql DBEq a => Expr a -> Expr a -> Expr Bool
76−(==.) = seq nullabilization
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
7751infix 4 ==.
52+{-# INLINABLE (==.) #-}
7853
7954
8055-- | Test if two expressions are different (not equal).
@@ -83,9 +58,12 @@ infix 4 ==.
8358-- @false@ when comparing two @null@ values. This differs from ordinary @=@
8459-- which would return @null@. This operator is closer to Haskell's '=='
8560-- operator. For an operator identical to SQL @=@, see '/=?'.
86−(/=.) :: Sql DBEq a => Expr a -> Expr a -> Expr Bool
87−(/=.) = sne nullabilization
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
8865infix 4 /=.
66+{-# INLINABLE (/=.) #-}
8967
9068
9169-- | Test if two expressions are equal. This operator is usually the best
@@ -94,14 +72,8 @@ infix 4 /=.
9472--
9573-- This corresponds to the SQL @=@ operator, though it will always return a
9674-- 'Bool'.
97−--
98−-- >>> select c $ pure $ lit Nothing ==? lit True
99−-- False
100−--
101−-- >>> select c $ pure $ lit Nothing ==? lit Nothing
102−-- False
10375(==?) :: DBEq a => Expr (Maybe a) -> Expr (Maybe a) -> Expr Bool
104−a ==? b = coalesce $ unsafeLiftOpNullable eq a b
76+a ==? b = coalesce $ unsafeLiftOpNull eq a b
10577infix 4 ==?
10678
10779
@@ -109,24 +81,21 @@ infix 4 ==?
10981--
11082-- This corresponds to the SQL @<>@ operator, though it will always return a
11183-- 'Bool'.
112−--
113−-- >>> select c $ pure $ lit Nothing /=? lit True
114−-- True
115−--
116−-- >>> select c $ pure $ lit Nothing /=? lit Nothing
117−-- False
11884(/=?) :: DBEq a => Expr (Maybe a) -> Expr (Maybe a) -> Expr Bool
119−a /=? b = coalesce $ unsafeLiftOpNullable ne a b
85+a /=? b = coalesce $ unsafeLiftOpNull ne a b
12086infix 4 /=?
12187
12288
12389-- | Like the SQL @IN@ operator, but implemented by folding over a list with
12490-- '==.' and '||.'.
125−--
126−-- >>> select c $ return $ lit (5 :: Int32) `in_` [ lit x | x <- [1..5] ]
127−-- [True]
128−--
129−-- >>> select c $ return $ lit (42 :: Int32) `in_` [ lit x | x <- [1..5] ]
130−-- [False]
131−in_ :: (Sql DBEq a, Foldable f) => Expr a -> f (Expr a) -> Expr Bool
132−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+2−33
@@ -20,12 +20,12 @@ 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 ( Sql )
28+import Rel8.Schema.Null ( Sql )
2929import Rel8.Type ( DBType )
3030
3131
@@ -47,42 +47,11 @@ instance (arg ~ Expr a, Function args res) => Function arg (args -> res) where
4747
4848-- | Construct an n-ary function that produces an 'Expr' that when called runs
4949-- a SQL function.
50−--
51−-- For example, here's how we can wrap PostgreSQL's @factorial@ function:
52−--
53−-- >>> :{
54−-- factorial :: Expr Int64 -> Expr Data.Scientific.Scientific
55−-- factorial = function "factorial"
56−-- :}
57−--
58−-- >>> select c $ pure $ factorial 5
59−-- [120.0]
60−--
61−-- The same approach works for any number of arguments:
62−--
63−-- >>> :{
64−-- power :: Expr Float -> Expr Float -> Expr Double
65−-- power = function "power"
66−-- :}
67−--
68−-- >>> select c $ pure $ power 9 3
69−-- [729.0]
7050function :: Function args result => String -> args -> result
7151function = applyArgument . Opaleye.FunExpr
7252
7353
7454-- | Construct a function call for functions with no arguments.
75−--
76−-- For example, we can call the database function @pi()@ by using
77−-- @nullaryFunction@:
78−--
79−-- >>> :{
80−-- sqlPi :: Expr Double
81−-- sqlPi = nullaryFunction "pi"
82−-- :}
83−--
84−-- >>> select c $ pure $ sqlPi
85−-- [3.141592653589793]
8655nullaryFunction :: Sql DBType a => String -> Expr a
8756nullaryFunction name = castExpr $ Expr (Opaleye.FunExpr name [])
8857
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+68−15
@@ -4,54 +4,107 @@
44{-# options_ghc -fno-warn-redundant-constraints #-}
55
66module Rel8.Expr.Num
7− ( 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
812 )
913where
1014
1115-- base
12−import Prelude ()
16+import Prelude ( (+), (-), fst, negate, signum, snd )
1317
1418-- rel
1519import Rel8.Expr ( Expr( Expr ) )
20+import Rel8.Expr.Eq ( (==.) )
1621import Rel8.Expr.Function ( function )
1722import Rel8.Expr.Opaleye ( castExpr )
18−import Rel8.Schema.Nullability ( IsMaybe, Sql )
23+import Rel8.Schema.Null ( Homonullable, Sql )
24+import Rel8.Table.Bool ( bool )
1925import Rel8.Type.Num ( DBFractional, DBIntegral, DBNum )
2026
2127
22−fromIntegral :: (Sql DBIntegral a, Sql DBNum b, IsMaybe a ~ IsMaybe b)
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)
2331 => Expr a -> Expr b
2432fromIntegral (Expr a) = castExpr (Expr a)
2533
2634
27−realToFrac :: (Sql DBNum a, Sql DBFractional b, IsMaybe a ~ IsMaybe b)
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)
2838 => Expr a -> Expr b
2939realToFrac (Expr a) = castExpr (Expr a)
3040
3141
32−ceiling :: (Sql DBFractional a, Sql DBIntegral b, IsMaybe a ~ IsMaybe b)
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)
3347 => Expr a -> Expr b
34−ceiling = function "CEILING"
48+ceiling = function "ceiling"
3549
3650
51+-- | Emulates the behaviour of the Haskell function 'Prelude.div' in
52+-- PostgreSQL.
3753div :: Sql DBIntegral a => Expr a -> Expr a -> Expr a
38−div = function "DIV"
54+div n d = fst (divMod n d)
3955
4056
57+-- | Emulates the behaviour of the Haskell function 'Prelude.mod' in
58+-- PostgreSQL.
4159mod :: Sql DBIntegral a => Expr a -> Expr a -> Expr a
42−mod = function "MOD"
60+mod n d = snd (divMod n d)
4361
4462
45−floor :: (Sql DBFractional a, Sql DBIntegral b, IsMaybe a ~ IsMaybe b)
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)
4693 => Expr a -> Expr b
47−floor = function "FLOOR"
94+floor = function "floor"
4895
4996
50−round :: (Sql DBFractional a, Sql DBIntegral b, IsMaybe a ~ IsMaybe b)
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)
51102 => Expr a -> Expr b
52−round = function "ROUND"
103+round = function "round"
53104
54105
55−truncate :: (Sql DBFractional a, Sql DBIntegral b, IsMaybe a ~ IsMaybe b)
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)
56109 => Expr a -> Expr b
57−truncate = function "TRUNC"
110+truncate = function "trunc"
src/Rel8/Expr/Opaleye.hs+27−13
@@ -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, Sql, 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 )
32+
3233
3334castExpr :: Sql DBType a => Expr a -> Expr a
34−castExpr = scastExpr nullabilization typeInformation
35+castExpr = scastExpr typeInformation
3536
3637
38+-- | Cast an expression to a different type. Corresponds to a @CAST()@ function
39+-- call.
3740unsafeCastExpr :: Sql DBType b => Expr a -> Expr b
38−unsafeCastExpr = sunsafeCastExpr nullabilization typeInformation
41+unsafeCastExpr = sunsafeCastExpr typeInformation
3942
4043
41−scastExpr :: Nullability db a -> TypeInformation db -> Expr a -> Expr a
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 :: Sql DBType 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+33−53
@@ -1,6 +1,5 @@
11{-# language DataKinds #-}
22{-# language FlexibleContexts #-}
3−{-# language LambdaCase #-}
43{-# language GADTs #-}
54{-# language ScopedTypeVariables #-}
65{-# language TypeApplications #-}
@@ -8,8 +7,7 @@
87{-# options_ghc -fno-warn-redundant-constraints #-}
98
109module Rel8.Expr.Ord
11− ( slt, sle, sgt, sge
12− , (<.), (<=.), (>.), (>=.)
10+ ( (<.), (<=.), (>.), (>=.)
1311 , (<?), (<=?), (>?), (>=?)
1412 , leastExpr, greatestExpr
1513 )
@@ -24,12 +22,9 @@ import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
2422-- rel8
2523import Rel8.Expr ( Expr( Expr ) )
2624import Rel8.Expr.Bool ( (&&.), (||.), coalesce )
27−import Rel8.Expr.Null ( isNull, isNonNull, nullable, unsafeLiftOpNullable )
28−import Rel8.Expr.Opaleye ( zipPrimExprsWith )
29−import Rel8.Schema.Nullability
30− ( Nullability( NonNullable, Nullable )
31− , Sql, nullabilization
32− )
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 )
3328import Rel8.Type.Ord ( DBOrd )
3429
3530
@@ -49,87 +44,71 @@ ge :: DBOrd a => Expr a -> Expr a -> Expr Bool
4944ge = zipPrimExprsWith (Opaleye.BinExpr (Opaleye.:>=))
5045
5146
52−slt :: DBOrd db => Nullability db a -> Expr a -> Expr a -> Expr Bool
53−slt = \case
54− Nullable -> \ma mb -> isNull ma &&. isNonNull mb ||. ma <? mb
55− NonNullable -> lt
56−
57−
58−sle :: DBOrd db => Nullability db a -> Expr a -> Expr a -> Expr Bool
59−sle = \case
60− Nullable -> \ma mb -> isNull ma ||. ma <=? mb
61− NonNullable -> le
62−
63−
64−sgt :: DBOrd db => Nullability db a -> Expr a -> Expr a -> Expr Bool
65−sgt = \case
66− Nullable -> \ma mb -> isNonNull ma &&. isNull mb ||. ma >? mb
67− NonNullable -> gt
68−
69−
70−sge :: DBOrd db => Nullability db a -> Expr a -> Expr a -> Expr Bool
71−sge = \case
72− Nullable -> \ma mb -> isNull mb ||. ma >=? mb
73− NonNullable -> ge
74−
75−
7647-- | Corresponds to the SQL @<@ operator. Note that this differs from SQL @<@
7748-- as @null@ will sort below any other value. For a version of @<@ that exactly
7849-- matches SQL, see '(<?)'.
79−(<.) :: Sql DBOrd a => Expr a -> Expr a -> Expr Bool
80−(<.) = slt nullabilization
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
8154infix 4 <.
8255
8356
8457-- | Corresponds to the SQL @<=@ operator. Note that this differs from SQL @<=@
8558-- as @null@ will sort below any other value. For a version of @<=@ that exactly
8659-- matches SQL, see '(<=?)'.
87−(<=.) :: Sql DBOrd a => Expr a -> Expr a -> Expr Bool
88−(<=.) = sle nullabilization
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
8964infix 4 <=.
9065
9166
9267-- | Corresponds to the SQL @>@ operator. Note that this differs from SQL @>@
9368-- as @null@ will sort below any other value. For a version of @>@ that exactly
9469-- matches SQL, see '(>?)'.
95−(>.) :: Sql DBOrd a => Expr a -> Expr a -> Expr Bool
96−(>.) = sgt nullabilization
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
9774infix 4 >.
9875
9976
10077-- | Corresponds to the SQL @>=@ operator. Note that this differs from SQL @>@
10178-- as @null@ will sort below any other value. For a version of @>=@ that
10279-- exactly matches SQL, see '(>=?)'.
103−(>=.) :: Sql DBOrd a => Expr a -> Expr a -> Expr Bool
104−(>=.) = sge nullabilization
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
10584infix 4 >=.
10685
10786
10887-- | Corresponds to the SQL @<@ operator. Returns @null@ if either arguments
10988-- are @null@.
11089(<?) :: DBOrd a => Expr (Maybe a) -> Expr (Maybe a) -> Expr Bool
111−a <? b = coalesce $ unsafeLiftOpNullable lt a b
90+a <? b = coalesce $ unsafeLiftOpNull lt a b
11291infix 4 <?
11392
11493
11594-- | Corresponds to the SQL @<=@ operator. Returns @null@ if either arguments
11695-- are @null@.
11796(<=?) :: DBOrd a => Expr (Maybe a) -> Expr (Maybe a) -> Expr Bool
118−a <=? b = coalesce $ unsafeLiftOpNullable le a b
97+a <=? b = coalesce $ unsafeLiftOpNull le a b
11998infix 4 <=?
12099
121100
122101-- | Corresponds to the SQL @>@ operator. Returns @null@ if either arguments
123102-- are @null@.
124103(>?) :: DBOrd a => Expr (Maybe a) -> Expr (Maybe a) -> Expr Bool
125−a >? b = coalesce $ unsafeLiftOpNullable gt a b
104+a >? b = coalesce $ unsafeLiftOpNull gt a b
126105infix 4 >?
127106
128107
129108-- | Corresponds to the SQL @>=@ operator. Returns @null@ if either arguments
130109-- are @null@.
131110(>=?) :: DBOrd a => Expr (Maybe a) -> Expr (Maybe a) -> Expr Bool
132−a >=? b = coalesce $ unsafeLiftOpNullable ge a b
111+a >=? b = coalesce $ unsafeLiftOpNull ge a b
133112infix 4 >=?
134113
135114
@@ -138,11 +117,11 @@ infix 4 >=?
138117--
139118-- Corresponds to the SQL @least()@ function.
140119leastExpr :: forall a. Sql DBOrd a => Expr a -> Expr a -> Expr a
141−leastExpr ma mb = case nullabilization @a of
142− Nullable -> nullable ma (\a -> nullable mb (least_ a) mb) ma
143− NonNullable -> least_ ma mb
120+leastExpr ma mb = case nullable @a of
121+ Null -> nullableExpr ma (\a -> nullableExpr mb (least_ a) mb) ma
122+ NotNull -> least_ ma mb
144123 where
145− least_ (Expr a) (Expr b) = Expr (Opaleye.FunExpr "LEAST" [a, b])
124+ least_ a b = Expr (Opaleye.FunExpr "LEAST" [toPrimExpr a, toPrimExpr b])
146125
147126
148127-- | Given two expressions, return the expression that sorts greater than the
@@ -150,8 +129,9 @@ leastExpr ma mb = case nullabilization @a of
150129--
151130-- Corresponds to the SQL @greatest()@ function.
152131greatestExpr :: forall a. Sql DBOrd a => Expr a -> Expr a -> Expr a
153−greatestExpr ma mb = case nullabilization @a of
154− Nullable -> nullable mb (\a -> nullable ma (greatest_ a) mb) ma
155− NonNullable -> greatest_ ma mb
132+greatestExpr ma mb = case nullable @a of
133+ Null -> nullableExpr mb (\a -> nullableExpr ma (greatest_ a) mb) ma
134+ NotNull -> greatest_ ma mb
156135 where
157− 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−12
@@ -28,9 +28,6 @@ import Rel8.Type.Ord ( DBOrd )
2828
2929
3030-- | Sort a column in ascending order.
31−--
32−-- >>> select c $ orderBy asc $ values [ lit x | x <- [1..5 :: Int32] ]
33−-- [1,2,3,4,5]
3431asc :: DBOrd a => Order (Expr a)
3532asc = Order $ Opaleye.Order (\expr -> [(orderOp, toPrimExpr expr)])
3633 where
@@ -42,9 +39,6 @@ asc = Order $ Opaleye.Order (\expr -> [(orderOp, toPrimExpr expr)])
4239
4340
4441-- | Sort a column in descending order.
45−--
46−-- >>> select c $ orderBy desc $ values [ lit x | x <- [1..5 :: Int32] ]
47−-- [5,4,3,2,1]
4842desc :: DBOrd a => Order (Expr a)
4943desc = Order $ Opaleye.Order (\expr -> [(orderOp, toPrimExpr expr)])
5044 where
@@ -57,9 +51,6 @@ desc = Order $ Opaleye.Order (\expr -> [(orderOp, toPrimExpr expr)])
5751
5852-- | Transform an ordering so that @null@ values appear first. This corresponds
5953-- to @NULLS FIRST@ in SQL.
60−--
61−-- >>> select c $ orderBy (nullsFirst desc) $ values $ [ nullExpr, nullExpr ] <> [ lit (Just x) | x <- [1..5 :: Int32] ]
62−-- [Nothing,Nothing,Just 5,Just 4,Just 3,Just 2,Just 1]
6354nullsFirst :: Order (Expr a) -> Order (Expr (Maybe a))
6455nullsFirst (Order (Opaleye.Order f)) =
6556 Order $ Opaleye.Order $ fmap (first g) . f . unsafeUnnullify
@@ -70,9 +61,6 @@ nullsFirst (Order (Opaleye.Order f)) =
7061
7162-- | Transform an ordering so that @null@ values appear first. This corresponds
7263-- to @NULLS LAST@ in SQL.
73−--
74−-- >>> select c $ orderBy (nullsLast desc) $ values $ [ nullExpr, nullExpr ] <> [ lit (Just x) | x <- [1..5 :: Int32] ]
75−-- [Just 5,Just 4,Just 3,Just 2,Just 1,Nothing,Nothing]
7664nullsLast :: Order (Expr a) -> Order (Expr (Maybe a))
7765nullsLast (Order (Opaleye.Order f)) =
7866 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+16−15
@@ -21,28 +21,29 @@ import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
2121-- rel8
2222import {-# SOURCE #-} Rel8.Expr ( Expr( Expr ) )
2323import Rel8.Expr.Opaleye ( scastExpr )
24−import Rel8.Schema.Nullability
25− ( Nullability( Nullable, NonNullable )
26− , Sql, nullabilization
27− )
24+import Rel8.Schema.Null ( Unnullify, Nullity( Null, NotNull ), Sql, nullable )
2825import Rel8.Type ( DBType, typeInformation )
2926import Rel8.Type.Information ( TypeInformation(..) )
3027
3128
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.
3233litExpr :: Sql DBType a => a -> Expr a
33−litExpr = slitExpr nullabilization typeInformation
34+litExpr = slitExpr nullable typeInformation
3435
3536
36−slitExpr :: Nullability db a -> TypeInformation db -> a -> Expr a
37−slitExpr nullable info@TypeInformation {encode} =
38− 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
3940 where
40− encoder = case nullable of
41− Nullable -> maybe (Opaleye.ConstExpr Opaleye.NullLit) encode
42− NonNullable -> encode
41+ encoder = case nullity of
42+ Null -> maybe (Opaleye.ConstExpr Opaleye.NullLit) encode
43+ NotNull -> encode
4344
4445
45−sparseValue :: Nullability db a -> TypeInformation db -> Hasql.Row a
46−sparseValue nullability TypeInformation {decode, out} = case nullability of
47− Nullable -> Hasql.column $ Hasql.nullable $ out <$> decode
48− 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+27−26
@@ -13,7 +13,7 @@ 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
@@ -31,11 +31,12 @@ import Prelude
3131-- rel8
3232import Rel8.Expr ( Expr )
3333import Rel8.Expr.Function ( binaryOperator, nullaryFunction )
34−import Rel8.Expr.Opaleye ( unsafeCastExpr, unsafeLiteral )
34+import Rel8.Expr.Opaleye ( castExpr, unsafeCastExpr, unsafeLiteral )
3535
3636-- time
3737import Data.Time.Calendar ( Day )
38−import Data.Time.Clock ( DiffTime, UTCTime )
38+import Data.Time.Clock ( UTCTime )
39+import Data.Time.LocalTime ( CalendarDiffTime )
3940
4041
4142-- | Corresponds to @date(now())@.
@@ -74,93 +75,93 @@ now = nullaryFunction "now"
7475
7576
7677-- | Add a time interval to a point in time, yielding a new point in time.
77−addTime :: Expr DiffTime -> Expr UTCTime -> Expr UTCTime
78+addTime :: Expr CalendarDiffTime -> Expr UTCTime -> Expr UTCTime
7879addTime = flip (binaryOperator "+")
7980
8081
8182-- | Find the duration between two times.
82−diffTime :: Expr UTCTime -> Expr UTCTime -> Expr DiffTime
83+diffTime :: Expr UTCTime -> Expr UTCTime -> Expr CalendarDiffTime
8384diffTime = binaryOperator "-"
8485
8586
8687-- | Subtract a time interval from a point in time, yielding a new point in time.
87−subtractTime :: Expr DiffTime -> Expr UTCTime -> Expr UTCTime
88+subtractTime :: Expr CalendarDiffTime -> Expr UTCTime -> Expr UTCTime
8889subtractTime = flip (binaryOperator "-")
8990
9091
91−scaleInterval :: Expr Double -> Expr DiffTime -> Expr DiffTime
92+scaleInterval :: Expr Double -> Expr CalendarDiffTime -> Expr CalendarDiffTime
9293scaleInterval = binaryOperator "*"
9394
9495
9596-- | An interval of one second.
96−second :: Expr DiffTime
97+second :: Expr CalendarDiffTime
9798second = singleton "second"
9899
99100
100−-- | Create a literal interval from an integral number of seconds.
101−seconds :: Expr Double -> Expr DiffTime
101+-- | Create a literal interval from a number of seconds.
102+seconds :: Expr Double -> Expr CalendarDiffTime
102103seconds = (`scaleInterval` second)
103104
104105
105106-- | An interval of one minute.
106−minute :: Expr DiffTime
107+minute :: Expr CalendarDiffTime
107108minute = singleton "minute"
108109
109110
110−-- | Create a literal interval from an integral number of minutes.
111−minutes :: Expr Double -> Expr DiffTime
111+-- | Create a literal interval from a number of minutes.
112+minutes :: Expr Double -> Expr CalendarDiffTime
112113minutes = (`scaleInterval` minute)
113114
114115
115116-- | An interval of one hour.
116−hour :: Expr DiffTime
117+hour :: Expr CalendarDiffTime
117118hour = singleton "hour"
118119
119120
120−-- | Create a literal interval from an integral number of hours.
121−hours :: Expr Double -> Expr DiffTime
121+-- | Create a literal interval from a number of hours.
122+hours :: Expr Double -> Expr CalendarDiffTime
122123hours = (`scaleInterval` hour)
123124
124125
125126-- | An interval of one day.
126−day :: Expr DiffTime
127+day :: Expr CalendarDiffTime
127128day = singleton "day"
128129
129130
130131-- | Create a literal interval from a number of days.
131−days :: Expr Double -> Expr DiffTime
132+days :: Expr Double -> Expr CalendarDiffTime
132133days = (`scaleInterval` day)
133134
134135
135136-- | An interval of one week.
136−week :: Expr DiffTime
137+week :: Expr CalendarDiffTime
137138week = singleton "week"
138139
139140
140141-- | Create a literal interval from a number of weeks.
141−weeks :: Expr Double -> Expr DiffTime
142+weeks :: Expr Double -> Expr CalendarDiffTime
142143weeks = (`scaleInterval` week)
143144
144145
145146-- | An interval of one month.
146−month :: Expr DiffTime
147+month :: Expr CalendarDiffTime
147148month = singleton "month"
148149
149150
150151-- | Create a literal interval from a number of months.
151−months :: Expr Double -> Expr DiffTime
152+months :: Expr Double -> Expr CalendarDiffTime
152153months = (`scaleInterval` month)
153154
154155
155156-- | An interval of one year.
156−year :: Expr DiffTime
157+year :: Expr CalendarDiffTime
157158year = singleton "year"
158159
159160
160161-- | Create a literal interval from a number of years.
161−years :: Expr Double -> Expr DiffTime
162+years :: Expr Double -> Expr CalendarDiffTime
162163years = (`scaleInterval` year)
163164
164165
165−singleton :: String -> Expr DiffTime
166−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.hs+9−1
@@ -3,7 +3,11 @@
33{-# language StandaloneKindSignatures #-}
44{-# language TypeFamilies #-}
55
6−module Rel8.FCF ( Exp, Eval ) where
6+module Rel8.FCF
7+ ( Exp, Eval
8+ , Id
9+ )
10+where
711
812-- base
913import Data.Kind ( Type )
@@ -16,3 +20,7 @@ type Exp e = e -> Type
1620
1721type Eval :: Exp e -> e
1822type 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+5−14
@@ -16,24 +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 'asc'
23−-- and 'desc', and you can combine @Order@ via its various instances.
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.
2425--
2526-- A common pattern is to use '<>' to combine multiple orderings in sequence,
26−-- and '>$<' (from 'Contravariant') to select individual columns. For example,
27−-- to sort a @Query@ on two columns, we could do:
28−--
29−-- >>> import Data.Functor.Contravariant ((>$<))
30−-- >>> :{
31−-- select c $ orderBy (mconcat [fst >$< asc, snd >$< desc]) $ do
32−-- x <- values [ lit x | x <- [1..3 :: Int32 ] ]
33−-- y <- values [ lit x | x <- [1..3 :: Int32 ] ]
34−-- return (x, y)
35−-- :}
36−-- [(1,3),(1,2),(1,1),(2,3),(2,2),(2,1),(3,3),(3,2),(3,1)]
27+-- and 'Data.Functor.Contravariant.>$<' to select individual columns.
3728type Order :: Type -> Type
3829newtype Order a = Order (Opaleye.Order a)
3930 deriving newtype (Contravariant, Divisible, Decidable, Semigroup, Monoid)
src/Rel8/Query.hs+181−8
@@ -1,7 +1,6 @@
1−{-# language DerivingStrategies #-}
2−{-# language DerivingVia #-}
3−{-# language GeneralizedNewtypeDeriving #-}
1+{-# language FlexibleContexts #-}
42{-# language StandaloneKindSignatures #-}
3+{-# language UndecidableInstances #-}
54
65module Rel8.Query
76 ( Query( Query )
@@ -9,37 +8,201 @@ module Rel8.Query
98where
109
1110-- base
11+import Control.Applicative ( liftA2 )
12+import Control.Monad ( liftM2 )
1213import Data.Kind ( Type )
14+import Data.Monoid ( Any( Any ) )
1315import Prelude
1416
1517-- opaleye
16−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
1723
1824-- rel8
25+import Rel8.Expr ( Expr )
1926import Rel8.Query.Set ( unionAll )
27+import Rel8.Query.Opaleye ( fromOpaleye )
2028import Rel8.Query.Values ( values )
29+import Rel8.Table ( Table, fromColumns, toColumns )
2130import Rel8.Table.Alternative
2231 ( AltTable, (<|>:)
2332 , AlternativeTable, emptyTable
2433 )
34+import Rel8.Table.Projection ( Projectable, apply, project )
2535
2636-- semigroupoids
27−import Data.Functor.Apply ( Apply, WrappedApplicative(..) )
37+import Data.Functor.Apply ( Apply, (<.>) )
2838import Data.Functor.Bind ( Bind, (>>-) )
2939
3040
3141-- | The @Query@ monad allows you to compose a @SELECT@ query. This monad has
3242-- semantics similar to the list (@[]@) monad.
3343type Query :: Type -> Type
34−newtype Query a = Query (Opaleye.Select a)
35− deriving newtype (Functor, Applicative, Monad)
36− deriving Apply via (WrappedApplicative Opaleye.Select)
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+
170+
171+instance Applicative Query where
172+ pure = fromOpaleye . pure
173+ liftA2 = liftM2
37174
38175
39176instance Bind Query where
40177 (>>-) = (>>=)
41178
42179
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+
43206-- | '<|>:' = 'unionAll'.
44207instance AltTable Query where
45208 (<|>:) = unionAll
@@ -48,3 +211,13 @@ instance AltTable Query where
48211-- | 'emptyTable' = 'values' @[]@.
49212instance AlternativeTable Query where
50213 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+36−3
@@ -1,23 +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
2139-- | Apply an aggregation to all rows returned by a 'Query'.
22−aggregate :: Query (Aggregate exprs) -> Query exprs
40+aggregate :: Aggregates aggregates exprs => Query aggregates -> Query exprs
2341aggregate = 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+4−12
@@ -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 ) )
@@ -25,9 +22,6 @@ import Rel8.Table.Opaleye ( distinctspec, unpackspec )
2522
2623-- | Select all distinct rows from a query, removing duplicates. @distinct q@
2724-- is equivalent to the SQL statement @SELECT DISTINCT q@.
28−--
29−-- >>> select c $ distinct $ values [ lit True, lit True, lit False ]
30−-- [False,True]
3125distinct :: EqTable a => Query a -> Query a
3226distinct = mapOpaleye (Opaleye.distinctExplicit distinctspec)
3327
@@ -36,13 +30,11 @@ distinct = mapOpaleye (Opaleye.distinctExplicit distinctspec)
3630-- to a projection. If multiple rows have the same projection, it is
3731-- unspecified which row will be returned. If this matters, use 'distinctOnBy'.
3832distinctOn :: EqTable b => (a -> b) -> Query a -> Query a
39−distinctOn proj =
40− mapOpaleye (\q -> Opaleye.productQueryArr (Opaleye.distinctOn unpackspec proj . Opaleye.runSimpleQueryArr q))
33+distinctOn proj = mapOpaleye (Opaleye.distinctOnExplicit unpackspec proj)
4134
4235
4336-- | Select all distinct rows from a query, where rows are equivalent according
4437-- to a projection. If there are multiple rows with the same projection, the
4538-- first row according to the specified 'Order' will be returned.
4639distinctOnBy :: EqTable b => (a -> b) -> Order a -> Query a -> Query a
47−distinctOnBy proj (Order order) =
48− 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+4−8
@@ -1,4 +1,5 @@
11{-# language FlexibleContexts #-}
2+{-# language MonoLocalBinds #-}
23
34module Rel8.Query.Each
45 ( each
@@ -16,21 +17,16 @@ import Rel8.Query ( Query )
1617import Rel8.Query.Opaleye ( fromOpaleye )
1718import Rel8.Schema.Name ( Selects )
1819import Rel8.Schema.Table ( TableSchema )
19−import Rel8.Table ( fromColumns, toColumns )
20+import Rel8.Table.Cols ( fromCols, toCols )
2021import Rel8.Table.Opaleye ( table, unpackspec )
2122
2223
2324-- | Select each row from a table definition. This is equivalent to @FROM
2425-- table@.
25−--
26−-- >>> mapM_ print =<< select c (each projectSchema)
27−-- Project {projectAuthorId = 1, projectName = "rel8"}
28−-- Project {projectAuthorId = 2, projectName = "aeson"}
29−-- Project {projectAuthorId = 2, projectName = "text"}
3026each :: Selects names exprs => TableSchema names -> Query exprs
3127each =
32− fmap fromColumns .
28+ fmap fromCols .
3329 fromOpaleye .
3430 Opaleye.selectTableExplicit unpackspec .
3531 table .
36− fmap toColumns
32+ fmap toCols
src/Rel8/Query/Either.hs+34−30
@@ -3,63 +3,67 @@
33module Rel8.Query.Either
44 ( keepLeftTable
55 , keepRightTable
6− , bindEitherTable
76 , bitraverseEitherTable
87 )
98where
109
1110-- base
12−import Data.Functor ( (<&>) )
1311import Prelude
1412
13+-- comonad
14+import Control.Comonad ( extract )
15+
1516-- rel8
1617import Rel8.Expr ( Expr )
1718import Rel8.Expr.Eq ( (==.) )
1819import Rel8.Query ( Query )
1920import Rel8.Query.Filter ( where_ )
2021import Rel8.Query.Maybe ( optional )
21−import Rel8.Query.Set ( unionAll )
22−import Rel8.Table ( Table )
23−import Rel8.Table.Bool ( bool )
2422import Rel8.Table.Either
2523 ( EitherTable( EitherTable )
26− , leftTable, rightTable
2724 , isLeftTable, isRightTable
2825 )
2926import Rel8.Table.Maybe ( MaybeTable( MaybeTable ), isJustTable )
3027
3128
32−keepLeftTable :: EitherTable a b -> Query a
29+-- | Filter 'EitherTable's, keeping only 'leftTable's.
30+keepLeftTable :: EitherTable Expr a b -> Query a
3331keepLeftTable e@(EitherTable _ a _) = do
3432 where_ $ isLeftTable e
35− pure a
33+ pure (extract a)
3634
3735
38−keepRightTable :: EitherTable a b -> Query b
36+-- | Filter 'EitherTable's, keeping only 'rightTable's.
37+keepRightTable :: EitherTable Expr a b -> Query b
3938keepRightTable e@(EitherTable _ _ b) = do
4039 where_ $ isRightTable e
41− pure b
42−
43−
44−bindEitherTable :: (Table Expr a, Functor m)
45− => (i -> m (EitherTable a b)) -> EitherTable a i -> m (EitherTable a b)
46−bindEitherTable query e@(EitherTable input a i) = do
47− query i <&> \(EitherTable output a' b) ->
48− EitherTable (input <> output) (bool a a' (isRightTable e)) b
40+ pure (extract b)
4941
5042
51−bitraverseEitherTable :: (Table Expr c, Table Expr 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 :: ()
5260 => (a -> Query c)
5361 -> (b -> Query d)
54− -> EitherTable a b
55− -> Query (EitherTable c d)
56−bitraverseEitherTable f g e = traverseLeftTable `unionAll` traverseRightTable
57− where
58− traverseLeftTable = do
59− mc@(MaybeTable _ c) <- optional (f =<< keepLeftTable e)
60− where_ $ isJustTable mc ==. isLeftTable e
61− pure $ leftTable c
62− traverseRightTable = do
63− md@(MaybeTable _ d) <- optional (g =<< keepRightTable e)
64− where_ $ isJustTable md ==. isRightTable e
65− 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+21−49
@@ -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
@@ -11,84 +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
2626-- | Checks if a query returns at least one row.
27−--
28−-- >>> :{
29−-- mapM_ print =<< select c do
30−-- author <- each authorSchema
31−-- hasProjects <- exists do
32−-- project <- each projectSchema
33−-- where_ $ authorId author ==. projectAuthorId project
34−-- return (authorName author, hasProjects)
35−-- :}
36−-- ("Ollie",True)
37−-- ("Bryan O'Sullivan",True)
38−-- ("Emily Pillmore",False)
3927exists :: Query a -> Query (Expr Bool)
40−exists = fmap isJustTable . optional . whereExists
41−-- FIXME: change this when b7aacc07c6392654cae439fc3b997620c3aa7a87 makes it
42−-- into a release of Opaleye
28+exists = fmap (fromPrimExpr . fromColumn) . mapOpaleye Opaleye.exists
4329
4430
4531inQuery :: EqTable a => a -> Query a -> Query (Expr Bool)
4632inQuery a = exists . (>>= filter (a ==:))
4733
4834
49−-- | Produce the empty query if the given query returns no rows. @whereExists@
35+-- | Produce the empty query if the given query returns no rows. @present@
5036-- is equivalent to @WHERE EXISTS@ in SQL.
51−--
52−-- >>> :{
53−-- select c do
54−-- author <- each authorSchema
55−-- whereExists do
56−-- project <- each projectSchema
57−-- where_ $ projectAuthorId project ==. authorId author
58−-- return $ authorName author
59−-- :}
60−-- ["Ollie","Bryan O'Sullivan"]
61−whereExists :: Query a -> Query ()
62−whereExists = mapOpaleye Opaleye.restrictExists
63−
64−
65−-- | Produce the empty query if the given query returns rows. @whereNotExists@
37+present :: Query a -> Query ()
38+present = mapOpaleye Opaleye.restrictExists
39+
40+
41+-- | Produce the empty query if the given query returns rows. @absent@
6642-- is equivalent to @WHERE NOT EXISTS@ in SQL.
67−--
68−-- >>> :{
69−-- select c do
70−-- author <- each authorSchema
71−-- whereNotExists do
72−-- project <- each projectSchema
73−-- where_ $ projectAuthorId project ==. authorId author
74−-- return $ authorName author
75−-- :}
76−-- ["Emily Pillmore"]
77−whereNotExists :: Query a -> Query ()
78−whereNotExists = mapOpaleye Opaleye.restrictNotExists
43+absent :: Query a -> Query ()
44+absent = mapOpaleye Opaleye.restrictNotExists
7945
8046
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'.
8150with :: (a -> Query b) -> a -> Query a
82−with f a = a <$ whereExists (f a)
51+with f a = a <$ present (f a)
8352
8453
54+-- | Like @with@, but with a custom membership test.
8555withBy :: (a -> b -> Expr Bool) -> Query b -> a -> Query a
8656withBy predicate bs = with $ \a -> bs >>= filter (predicate a)
8757
8858
59+-- | Filter rows where @a -> Query b@ yields no rows.
8960without :: (a -> Query b) -> a -> Query a
90−without f a = a <$ whereNotExists (f a)
61+without f a = a <$ absent (f a)
9162
9263
64+-- | Like @without@, but with a custom membership test.
9365withoutBy :: (a -> b -> Expr Bool) -> Query b -> a -> Query a
9466withoutBy predicate bs = without $ \a -> bs >>= filter (predicate a)
src/Rel8/Query/Filter.hs−11
@@ -24,23 +24,12 @@ import Rel8.Query.Opaleye ( fromOpaleye )
2424-- return @x@ unchanged when @f x@ is @True@. This is similar to
2525-- 'Control.Monad.guard', but as the predicate is separate from the argument,
2626-- it is easy to use in a pipeline of 'Query' transformations.
27−--
28−-- >>> select c $ values [ lit x | x <- [ 1..5 :: Int32 ] ] >>= filter (>. 3)
29−-- [4,5]
3027filter :: (a -> Expr Bool) -> a -> Query a
3128filter f a = a <$ where_ (f a)
3229
3330
3431-- | Drop any rows that don't match a predicate. @where_ expr@ is equivalent
3532-- to the SQL @WHERE expr@.
36−--
37−-- >>> :{
38−-- select c $ do
39−-- x <- values [ lit x | x <- [ 1..5 :: Int32 ] ]
40−-- where_ $ x >. lit 2
41−-- return x
42−-- :}
43−-- [3,4,5]
4433where_ :: Expr Bool -> Query ()
4534where_ condition =
4635 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−6
@@ -17,17 +17,11 @@ import Rel8.Query.Opaleye ( mapOpaleye )
1717
1818-- | @limit n@ select at most @n@ rows from a query. @limit n@ is equivalent
1919-- to the SQL @LIMIT n@.
20−--
21−-- >>> select c $ limit 3 $ values [ lit x | x <- [ 1..5 :: Int32 ] ]
22−-- [1,2,3]
2320limit :: Word -> Query a -> Query a
2421limit = mapOpaleye . Opaleye.limit . fromIntegral
2522
2623
2724-- | @offset n@ drops the first @n@ rows from a query. @offset n@ is equivalent
2825-- to the SQL @OFFSET n@.
29−--
30−-- >>> select c $ offset 3 $ values [ lit x | x <- [ 1..5 :: Int32 ] ]
31−-- [4,5]
3226offset :: Word -> Query a -> Query a
3327offset = mapOpaleye . Opaleye.offset . fromIntegral
src/Rel8/Query/List.hs+93−14
@@ -1,23 +1,58 @@
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
1222import Rel8.Expr ( Expr )
23+import Rel8.Expr.Aggregate ( listAggExpr, nonEmptyAggExpr )
24+import Rel8.Expr.Opaleye ( mapPrimExpr )
1325import Rel8.Query ( Query )
1426import Rel8.Query.Aggregate ( aggregate )
1527import Rel8.Query.Maybe ( optional )
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)
2156
2257
2358-- | Aggregate a 'Query' into a 'NonEmptyTable'. If the supplied query returns
@@ -28,16 +63,60 @@ import Rel8.Table.NonEmpty ( NonEmptyTable )
2863--
2964-- @some@ is analogous to 'Control.Applicative.some' from
3065-- @Control.Applicative@.
31−some :: Table Expr a => Query a -> Query (NonEmptyTable a)
32−some = aggregate . fmap nonEmptyAgg
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)
3371
3472
35−-- | Aggregate a 'Query' into a 'ListTable'. If the supplied query returns 0
36−-- rows, this function will produce a 'Query' that returns one row containing
37−-- the empty @ListTable@. If the supplied @Query@ does return rows, @many@ will
38−-- return exactly one row, with a @ListTable@ collecting all returned rows.
39−--
40−-- @many@ is analogous to 'Control.Applicative.many' from
41−-- @Control.Applicative@.
42−many :: Table Expr a => Query a -> Query (ListTable a)
43−many = fmap (maybeTable mempty id) . optional . aggregate . fmap listAgg
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
109+
110+
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
117+
118+
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+33−101
@@ -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
@@ -9,35 +12,32 @@ 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
4343-- | Filter out 'MaybeTable's, returning only the tables that are not-null.
@@ -45,92 +45,24 @@ optional = mapOpaleye $ Opaleye.QueryArr . go
4545-- This operation can be used to "undo" the effect of 'optional', which
4646-- operationally is like turning a @LEFT JOIN@ back into a full @JOIN@. You
4747-- can think of this as analogous to 'Data.Maybe.catMaybes'.
48−--
49−-- To see this in action, first consider the following 'optional' query:
50−--
51−-- >>> :{
52−-- select c $ do
53−-- author <- each authorSchema
54−-- maybeRel8 <- optional $
55−-- each projectSchema
56−-- >>= filter (\p -> projectAuthorId p ==. authorId author)
57−-- >>= filter (\p -> projectName p ==. "rel8")
58−-- return (authorName author, projectName <$> maybeRel8)
59−-- :}
60−-- [("Ollie",Just "rel8"),("Bryan O'Sullivan",Nothing),("Emily Pillmore",Nothing)]
61−--
62−-- Here @optional@ is acting as a @LEFT JOIN@. We can turn this into a proper
63−-- join by using @catMaybeTable@ to filter out rows where the join failed:
64−--
65−-- >>> :{
66−-- select c $ do
67−-- author <- each authorSchema
68−-- maybeRel8 <- optional $
69−-- each projectSchema
70−-- >>= filter (\p -> projectAuthorId p ==. authorId author)
71−-- >>= filter (\p -> projectName p ==. "rel8")
72−-- rel8 <- catMaybeTable maybeRel8
73−-- return (authorName author, projectName rel8)
74−-- :}
75−-- [("Ollie","rel8")]
76−catMaybeTable :: MaybeTable a -> Query a
48+catMaybeTable :: MaybeTable Expr a -> Query a
7749catMaybeTable ma@(MaybeTable _ a) = do
7850 where_ $ isJustTable ma
79− pure a
80−
81−
82−-- | @bindMaybeTable f x@ is similar to the monadic bind (@>>=@) operation. It
83−-- allows you to "extend" an optional query with another query. If either the
84−-- input or output are 'noTable', then the result is 'noTable'.
85−--
86−-- This is similar to 'traverseMaybeTable', followed by a @join@ on the
87−-- resulting @MaybeTable@s.
88−--
89−-- >>> select c $ bindMaybeTable (optional . values . pure . not_) =<< optional (values [lit True])
90−-- [Just False]
91−--
92−-- >>> select c $ bindMaybeTable (\_ -> return (noTable :: MaybeTable (Expr Bool))) =<< optional (values [lit True])
93−-- [Nothing]
94−--
95−-- >>> select c $ bindMaybeTable (optional . values . pure . not_) =<< return (noTable :: MaybeTable (Expr Bool))
96−-- [Nothing]
97−bindMaybeTable :: Monad m
98− => (a -> m (MaybeTable b)) -> MaybeTable a -> m (MaybeTable b)
99−bindMaybeTable query (MaybeTable input a) = do
100− MaybeTable output b <- query a
101− pure $ MaybeTable (input <> output) b
51+ pure (extract a)
10252
10353
10454-- | Extend an optional query with another query. This is useful if you want
10555-- to step through multiple @LEFT JOINs@.
10656--
10757-- Note that @traverseMaybeTable@ takes a @a -> Query b@ function, which means
108−-- you also have the ability to "expand" one row into multiple rows.
109−--
110−-- >>> :{
111−-- duplicate :: Expr Bool -> Query (Expr Bool)
112−-- duplicate x = unionAll (return x) (return x)
113−-- :}
114−--
115−-- >>> select c $ traverseMaybeTable duplicate =<< optional (values [lit True])
116−-- [Just True,Just True]
117−--
118−-- Note that if the @a -> Query b@ function returns no rows, then the resulting
119−-- query will also have no rows:
120−--
121−-- >>> select c $ traverseMaybeTable (limit 0 . pure) =<< optional (values [lit True])
122−-- []
123−--
124−-- However, regardless of the given @a -> Query b@ function, if the input is
125−-- @noTable@, you will always get exactly one @noTable@ back:
126−--
127−-- >>> select c $ traverseMaybeTable duplicate (noTable :: MaybeTable (Expr Bool))
128−-- [Nothing]
129−--
130−-- >>> select c $ traverseMaybeTable (limit 0 . pure) (noTable :: MaybeTable (Expr Bool))
131−-- [Nothing]
132−traverseMaybeTable :: (a -> Query b) -> MaybeTable a -> Query (MaybeTable b)
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)
13364traverseMaybeTable query ma@(MaybeTable input _) = do
134− MaybeTable output b <- optional (query =<< catMaybeTable ma)
135− where_ $ output ==. input
136− 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/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+6−59
@@ -1,74 +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 ( Expr, Col(..) )
27−import Rel8.Expr.Opaleye ( toPrimExpr )
13+import Rel8.Expr ( Expr )
2814import Rel8.Query ( Query )
29−import Rel8.Query.Opaleye ( toOpaleye )
30−import qualified Rel8.Query.Optimize as Rel8 ( optimize )
31−import Rel8.Schema.Name ( Selects, Col(..) )
32−import Rel8.Schema.HTable ( htabulateA, hfield )
33−import Rel8.Table ( Table, toColumns )
34−import Rel8.Table.Name ( namesFromLabels )
15+import Rel8.Statement.Select ( ppSelect )
16+import Rel8.Table ( Table )
3517
3618
37−-- | Convert a query to a 'String' containing the query as a @SELECT@
38−-- statement.
19+-- | Convert a 'Query' to a 'String' containing a @SELECT@ statement.
3920showQuery :: Table Expr a => Query a -> String
40−showQuery = fold . sqlForQuery
41−
42−
43−sqlForQuery :: Table Expr a
44− => Query a -> Maybe String
45−sqlForQuery = sqlForQueryWithNames namesFromLabels . fmap toColumns
46−
47−
48−sqlForQueryWithNames :: Selects names exprs
49− => names -> Query exprs -> Maybe String
50−sqlForQueryWithNames names query =
51− show . Opaleye.ppSql . selectFrom names exprs <$> optimize primQuery
52− where
53− (exprs, primQuery, _) =
54− Opaleye.runSimpleQueryArrStart (toOpaleye query) ()
55−
56−
57−optimize :: Opaleye.PrimQuery' a -> Maybe (Opaleye.PrimQuery' Void)
58−optimize = Opaleye.removeEmpty . Rel8.optimize . Opaleye.optimize
59−
60−
61−selectFrom :: Selects names exprs
62− => names -> exprs -> Opaleye.PrimQuery' Void -> Opaleye.Select
63−selectFrom (toColumns -> names) (toColumns -> exprs) query =
64− Opaleye.SelectFrom $ Opaleye.newSelect
65− { Opaleye.attrs = Opaleye.SelectAttrs attributes
66− , Opaleye.tables = Opaleye.oneTable select
67− }
68− where
69− select = Opaleye.foldPrimQuery Opaleye.sqlQueryGenerator query
70− attributes = getConst $ htabulateA $ \field -> case hfield names field of
71− NameCol name -> case hfield exprs field of
72− DB (toPrimExpr -> expr) -> Const (pure (makeAttr name expr))
73− makeAttr label expr =
74− (Opaleye.sqlExpr expr, Just (Opaleye.SqlColumn label))
21+showQuery = show . ppSelect
src/Rel8/Query/Set.hs+8−26
@@ -23,54 +23,36 @@ import Rel8.Table.Opaleye ( binaryspec )
2323
2424
2525-- | Combine the results of two queries of the same type, collapsing
26−-- duplicates. @union a b@ is the same as the SQL statement @x UNION b@.
27−--
28−-- >>> select c $ values [lit True, lit True, lit False] `union` values [lit True]
29−-- [False,True]
26+-- duplicates. @union a b@ is the same as the SQL statement @a UNION b@.
3027union :: EqTable a => Query a -> Query a -> Query a
3128union = zipOpaleyeWith (Opaleye.unionExplicit binaryspec)
3229
3330
3431-- | Combine the results of two queries of the same type, retaining duplicates.
35−-- @unionAll a b@ is the same as the SQL statement @x UNION ALL b@.
36−--
37−-- >>> select c $ values [lit True, lit True, lit False] `unionAll` values [lit True]
38−-- [True,True,False,True]
32+-- @unionAll a b@ is the same as the SQL statement @a UNION ALL b@.
3933unionAll :: Table Expr a => Query a -> Query a -> Query a
4034unionAll = zipOpaleyeWith (Opaleye.unionAllExplicit binaryspec)
4135
4236
4337-- | Find the intersection of two queries, collapsing duplicates. @intersect a
44−-- b@ is the same as the SQL statement @x INTERSECT b@.
45−--
46−-- >>> select c $ values [lit True, lit True, lit False] `intersect` values [lit True]
47−-- [True]
38+-- b@ is the same as the SQL statement @a INTERSECT b@.
4839intersect :: EqTable a => Query a -> Query a -> Query a
4940intersect = zipOpaleyeWith (Opaleye.intersectExplicit binaryspec)
5041
5142
5243-- | Find the intersection of two queries, retaining duplicates. @intersectAll
53−-- a b@ is the same as the SQL statement @x INTERSECT ALL b@.
54−--
55−-- >>> select c $ values [lit True, lit True, lit False] `intersectAll` values [lit True, lit True]
56−-- [True,True]
57−intersectAll :: Table Expr a => Query a -> Query a -> Query a
44+-- a b@ is the same as the SQL statement @a INTERSECT ALL b@.
45+intersectAll :: EqTable a => Query a -> Query a -> Query a
5846intersectAll = zipOpaleyeWith (Opaleye.intersectAllExplicit binaryspec)
5947
6048
6149-- | Find the difference of two queries, collapsing duplicates @except a b@ is
62−-- the same as the SQL statement @x INTERSECT b@.
63−--
64−-- >>> select c $ values [lit True, lit False, lit False] `except` values [lit True]
65−-- [False]
50+-- the same as the SQL statement @a EXCEPT b@.
6651except :: EqTable a => Query a -> Query a -> Query a
6752except = zipOpaleyeWith (Opaleye.exceptExplicit binaryspec)
6853
6954
7055-- | Find the difference of two queries, retaining duplicates. @exceptAll a b@
71−-- is the same as the SQL statement @x EXCEPT ALL b@.
72−--
73−-- >>> select c $ values [lit True, lit False, lit False] `exceptAll` values [lit True]
74−-- [False,False]
75−exceptAll :: Table Expr a => Query a -> Query a -> Query a
56+-- is the same as the SQL statement @a EXCEPT ALL b@.
57+exceptAll :: EqTable a => Query a -> Query a -> Query a
7658exceptAll = zipOpaleyeWith (Opaleye.exceptAllExplicit binaryspec)
src/Rel8/Query/These.hs+62−53
@@ -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.Table ( Table )
3337import Rel8.Table.Either ( EitherTable( EitherTable ) )
3438import Rel8.Table.Maybe ( MaybeTable( MaybeTable ), isJustTable )
35−import Rel8.Table.Opaleye ( unpackspec )
3639import Rel8.Table.These
37− ( TheseTable( TheseTable )
40+ ( TheseTable( TheseTable, here, there )
41+ , hasHereTable, hasThereTable
3842 , isThisTable, isThatTable, isThoseTable
3943 )
4044import Rel8.Type.Tag ( EitherTag( IsLeft, IsRight ) )
4145
4246
4347-- | Corresponds to a @FULL OUTER JOIN@ between two queries.
44−alignBy :: (Table Expr a, Table Expr b)
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 Expr 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 Expr c, Table Expr 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+1−7
@@ -21,13 +21,7 @@ import Rel8.Table.Opaleye ( valuesspec )
2121
2222
2323-- | Construct a query that returns the given input list of rows. This is like
24−-- folding a list of 'return' statements under 'union', but uses the SQL
24+-- folding a list of 'return' statements under 'Rel8.union', but uses the SQL
2525-- @VALUES@ expression for efficiency.
26−--
27−-- Typically @values@ will be used with 'lit':
28−--
29−-- >>> mapM_ Data.Text.IO.putStrLn =<< select c (values [ lit "Hello", lit "World!" ])
30−-- Hello
31−-- World!
3226values :: (Table Expr a, Foldable f) => f a -> Query a
3327values = 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−170
@@ -1,170 +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.Functor.Identity ( Identity )
17−import Data.Kind ( Type )
18−import Data.List.NonEmpty ( NonEmpty )
19−import GHC.TypeLits ( Symbol )
20−import Prelude
21−
22−-- rel8
23−import Rel8.Aggregate ( Aggregate )
24−import Rel8.Expr ( Expr )
25−import Rel8.Kind.Labels ( Labels )
26−import Rel8.Kind.Necessity ( Necessity( Required, Optional ) )
27−import Rel8.Schema.Field ( Field )
28−import Rel8.Schema.Insert ( Insert )
29−import qualified Rel8.Schema.Kind as K
30−import Rel8.Schema.Name ( Name )
31−import Rel8.Schema.Nullability ( Unnullify )
32−import Rel8.Schema.Structure
33− ( Structure
34− , Shape( Either, List, Maybe, NonEmpty, These )
35− , Shape1
36− , Shape2
37− )
38−import Rel8.Table.Either ( EitherTable )
39−import Rel8.Table.List ( ListTable )
40−import Rel8.Table.Maybe ( MaybeTable )
41−import Rel8.Table.NonEmpty ( NonEmptyTable )
42−import Rel8.Table.These ( TheseTable )
43−
44−-- these
45−import Data.These ( These )
46−
47−
48−type Label :: Symbol -> Type -> Type
49−data Label label a
50−
51−
52−type Default :: Type -> Type
53−data Default a
54−
55−
56−type GetLabel :: Type -> Labels
57−type family GetLabel a where
58− GetLabel (Label label _) = '[label]
59− GetLabel _ = '[]
60−
61−
62−type UnwrapLabel :: Type -> Type
63−type family UnwrapLabel a where
64− UnwrapLabel (Label _ a) = a
65− UnwrapLabel a = a
66−
67−
68−type GetNecessity :: Type -> Necessity
69−type family GetNecessity a where
70− GetNecessity (Default _) = 'Optional
71− GetNecessity _ = 'Required
72−
73−
74−type UnwrapDefault :: Type -> Type
75−type family UnwrapDefault a where
76− UnwrapDefault (Default a) = a
77− UnwrapDefault a = a
78−
79−
80−-- | The @Column@ type family should be used to indicate which fields of your
81−-- data types are single columns in queries. This type family has special
82−-- support when a query is executed, allowing you to use a single data type for
83−-- both query data and rows decoded to Haskell.
84−--
85−-- To understand why this type family is special, let's consider a simple
86−-- higher-kinded data type of Haskell packages:
87−--
88−-- >>> :{
89−-- data Package f = Package
90−-- { packageName :: Column f Text
91−-- , packageAuthor :: Column f Text
92−-- }
93−-- :}
94−--
95−-- In queries, @f@ will be some type of 'Expr', and @Column Expr a@ reduces to
96−-- just @Expr a@:
97−--
98−-- >>> :t packageName (undefined :: Package Expr)
99−-- packageName (undefined :: Package Expr) :: Expr Text
100−--
101−-- When we 'select' queries of this type, @f@ will be instantiated as
102−-- @Identity@, at which point all wrapping entire disappears:
103−--
104−-- >>> :t packageName (undefined :: Package Identity)
105−-- packageName (undefined :: Package Identity) :: Text
106−--
107−-- In @rel8@ we try hard to always know what @f@ is, which means holes should
108−-- mention precise types, rather than the @Column@ type family. You should only
109−-- need to be aware of the type family when defining your table types.
110−type Column :: K.Context -> Type -> Type
111−type Column context a =
112− Field context (GetLabel a)
113− (GetNecessity (UnwrapLabel a))
114− (Unnullify (UnwrapDefault (UnwrapLabel a)))
115− (UnwrapDefault (UnwrapLabel a))
116−
117−
118−type HEither :: K.Context -> Type -> Type -> Type
119−type family HEither context where
120− HEither Structure = Shape2 'Either
121− HEither Aggregate = EitherTable
122− HEither Expr = EitherTable
123− HEither Identity = Either
124− HEither Insert = EitherTable
125− HEither Name = EitherTable
126− HEither _ = Either
127−
128−
129−type HList :: K.Context -> Type -> Type
130−type family HList context where
131− HList Structure = Shape1 'List
132− HList Aggregate = ListTable
133− HList Expr = ListTable
134− HList Identity = []
135− HList Insert = ListTable
136− HList Name = ListTable
137− HList _ = []
138−
139−
140−type HMaybe :: K.Context -> Type -> Type
141−type family HMaybe context where
142− HMaybe Structure = Shape1 'Maybe
143− HMaybe Aggregate = MaybeTable
144− HMaybe Expr = MaybeTable
145− HMaybe Identity = Maybe
146− HMaybe Insert = MaybeTable
147− HMaybe Name = MaybeTable
148− HMaybe _ = Maybe
149−
150−
151−type HNonEmpty :: K.Context -> Type -> Type
152−type family HNonEmpty context where
153− HNonEmpty Structure = Shape1 'NonEmpty
154− HNonEmpty Aggregate = NonEmptyTable
155− HNonEmpty Expr = NonEmptyTable
156− HNonEmpty Identity = NonEmpty
157− HNonEmpty Insert = NonEmptyTable
158− HNonEmpty Name = NonEmptyTable
159− HNonEmpty _ = NonEmpty
160−
161−
162−type HThese :: K.Context -> Type -> Type -> Type
163−type family HThese context where
164− HThese Structure = Shape2 'These
165− HThese Aggregate = TheseTable
166− HThese Expr = TheseTable
167− HThese Identity = These
168− HThese Insert = TheseTable
169− HThese Name = TheseTable
170− HThese _ = These
src/Rel8/Schema/Context.hsdeleted−28
@@ -1,28 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language GADTs #-}
3−{-# language StandaloneKindSignatures #-}
4−{-# language TypeFamilies #-}
5−
6−module Rel8.Schema.Context
7− ( Interpretation(..), Col( Result )
8− )
9−where
10−
11−-- base
12−import Data.Functor.Identity ( Identity )
13−import Data.Kind ( Constraint )
14−import Prelude ()
15−
16−-- rel8
17−import Rel8.Schema.Kind ( Context, HContext )
18−import Rel8.Schema.Spec ( Spec( Spec ) )
19−
20−
21−type Interpretation :: Context -> Constraint
22−class Interpretation context where
23− data Col context :: HContext
24−
25−
26−instance Interpretation Identity where
27− data Col Identity _spec where
28− Result :: a -> Col Identity ('Spec labels necessity db a)
src/Rel8/Schema/Context/Identity.hsdeleted−198
@@ -1,198 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language DisambiguateRecordFields #-}
3−{-# language NamedFieldPuns #-}
4−{-# language TypeFamilies #-}
5−
6−module Rel8.Schema.Context.Identity
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.Functor.Identity ( Identity )
18−import Data.List.NonEmpty ( NonEmpty )
19−import Prelude hiding ( null )
20−
21−-- rel8
22−import Rel8.Schema.Context ( Col( Result ) )
23−import Rel8.Schema.HTable ( HTable )
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 (Col Identity)) (u (Col Identity))
45− -> HEitherTable t u (Col Identity)
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 (Col Identity)
63− -> Either (t (Col Identity)) (u (Col Identity))
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 (Col Identity)] -> HListTable t (Col Identity)
74−toHListTable = hvectorize vectorizer
75−{-# INLINABLE toHListTable #-}
76−
77−
78−fromHListTable :: HTable t => HListTable t (Col Identity) -> [t (Col Identity)]
79−fromHListTable = hunvectorize unvectorizer
80−{-# INLINABLE fromHListTable #-}
81−
82−
83−toHMaybeTable :: HTable t => Maybe (t (Col Identity)) -> HMaybeTable t (Col Identity)
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 (Col Identity) -> Maybe (t (Col Identity))
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 (Col Identity)) -> HNonEmptyTable t (Col Identity)
107−toHNonEmptyTable = hvectorize vectorizer
108−{-# INLINABLE toHNonEmptyTable #-}
109−
110−
111−fromHNonEmptyTable :: HTable t => HNonEmptyTable t (Col Identity) -> NonEmpty (t (Col Identity))
112−fromHNonEmptyTable = hunvectorize unvectorizer
113−{-# INLINABLE fromHNonEmptyTable #-}
114−
115−
116−toHTheseTable :: (HTable t, HTable u)
117− => These (t (Col Identity)) (u (Col Identity))
118− -> HTheseTable t u (Col Identity)
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 (Col Identity)
139− -> These (t (Col Identity)) (u (Col Identity))
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 :: Col Identity ('Spec labels necessity db (Maybe db))
159−null = Result Nothing
160−
161−
162−nullifier :: ()
163− => SSpec ('Spec labels necessity db a)
164− -> Col Identity ('Spec labels necessity db a)
165− -> Col Identity ('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− -> Col Identity ('Spec labels necessity db (Maybe db))
174− -> Maybe (Col Identity ('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 (Col Identity ('Spec labels necessity db a))
184− -> Col Identity ('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− -> Col Identity ('Spec labels necessity (f a) (f a))
191− -> f (Col Identity ('Spec labels necessity db a))
192−unvectorizer _ (Result results) = Result <$> results
193−
194−
195−relabel :: ()
196− => HIdentity ('Spec labels necessity db a) (Col Identity)
197− -> HIdentity ('Spec relabels necessity db a) (Col Identity)
198−relabel (HIdentity (Result a)) = HIdentity (Result a)
src/Rel8/Schema/Context/Label.hsdeleted−52
@@ -1,52 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language StandaloneKindSignatures #-}
3−{-# language TypeFamilies #-}
4−{-# language TypeOperators #-}
5−
6−module Rel8.Schema.Context.Label
7− ( Labelable( labeler, unlabeler )
8− , HLabelable( hlabeler, hunlabeler )
9− )
10−where
11−
12−-- base
13−import Data.Functor.Identity ( Identity )
14−import Data.Kind ( Constraint )
15−import Prelude hiding ( null )
16−
17−-- rel8
18−import Rel8.Schema.Context ( Interpretation, Col(..) )
19−import Rel8.Schema.Kind ( Context, HContext )
20−import Rel8.Schema.Spec ( Spec( Spec ) )
21−
22−
23−type Labelable :: Context -> Constraint
24−class Interpretation context => Labelable context where
25− labeler :: ()
26− => Col context ('Spec labels necessity db a)
27− -> Col context ('Spec (label ': labels) necessity db a)
28−
29− unlabeler :: ()
30− => Col context ('Spec (label ': labels) necessity db a)
31− -> Col context ('Spec labels necessity db a)
32−
33−
34−instance Labelable Identity where
35− labeler (Result a) = Result a
36− unlabeler (Result a) = Result a
37−
38−
39−type HLabelable :: HContext -> Constraint
40−class HLabelable context where
41− hlabeler :: ()
42− => context ('Spec labels necessity db a)
43− -> context ('Spec (label ': labels) necessity db a)
44−
45− hunlabeler :: ()
46− => context ('Spec (label ': labels) necessity db a)
47− -> context ('Spec labels necessity db a)
48−
49−
50−instance Labelable context => HLabelable (Col context) where
51− hlabeler = labeler
52− hunlabeler = unlabeler
src/Rel8/Schema/Context/Nullify.hs+111−43
@@ -1,76 +1,144 @@
11{-# language DataKinds #-}
2+{-# language EmptyCase #-}
23{-# language FlexibleContexts #-}
3−{-# language FlexibleInstances #-}
4−{-# language MultiParamTypeClasses #-}
4+{-# language GADTs #-}
5+{-# language LambdaCase #-}
6+{-# language NamedFieldPuns #-}
57{-# language StandaloneKindSignatures #-}
6−{-# language TypeFamilies #-}
78
89module Rel8.Schema.Context.Nullify
9− ( Nullifiable( encodeTag, decodeTag, nullifier, unnullifier )
10− , NullifiableEq
11− , unnull, runTag
10+ ( Nullifiability(..), NonNullifiability(..), nullifiableOrNot, absurd
11+ , Nullifiable, nullifiability
12+ , guarder, nullifier, unnullifier
13+ , sguard, snullify
1214 )
1315where
1416
1517-- base
16−import Data.Kind ( Constraint )
18+import Data.Bool ( bool )
19+import Data.Functor.Identity ( Identity( Identity ) )
20+import Data.Kind ( Constraint, Type )
1721import Prelude hiding ( null )
1822
1923-- opaleye
2024import qualified Opaleye.Internal.HaskellDB.PrimQuery as Opaleye
2125
2226-- rel8
23−import {-# SOURCE #-} Rel8.Expr ( Expr )
27+import Rel8.Aggregate ( Aggregate(..), zipOutputs )
28+import Rel8.Expr ( Expr )
2429import Rel8.Expr.Bool ( boolExpr )
2530import Rel8.Expr.Null ( nullify, unsafeUnnullify )
2631import Rel8.Expr.Opaleye ( fromPrimExpr )
27−import Rel8.Kind.Labels ( KnownLabels )
28−import Rel8.Kind.Necessity ( Necessity( Required ) )
29−import Rel8.Schema.Context ( Interpretation, Col(..) )
32+import Rel8.Kind.Context ( SContext(..) )
33+import Rel8.Schema.Field ( Field )
3034import qualified Rel8.Schema.Kind as K
31−import Rel8.Schema.Nullability ( Nullability( Nullable, NonNullable ), Sql )
32−import Rel8.Schema.Spec ( Spec( Spec ), SSpec )
33−import Rel8.Type.Eq ( DBEq )
34−import Rel8.Type.Monoid ( DBMonoid )
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(..) )
39+
40+
41+type Nullifiability :: K.Context -> Type
42+data Nullifiability context where
43+ NAggregate :: Nullifiability Aggregate
44+ NExpr :: Nullifiability Expr
45+ NName :: Nullifiability Name
3546
3647
3748type Nullifiable :: K.Context -> Constraint
38−class Interpretation context => Nullifiable context where
39− encodeTag :: (Sql DBEq a, KnownLabels labels)
40− => Expr a
41− -> Col context ('Spec labels 'Required db a)
49+class Nullifiable context where
50+ nullifiability :: Nullifiability context
51+
52+
53+instance Nullifiable Aggregate where
54+ nullifiability = NAggregate
55+
56+
57+instance Nullifiable Expr where
58+ nullifiability = NExpr
59+
60+
61+instance Nullifiable Name where
62+ nullifiability = NName
63+
4264
43− decodeTag :: Sql DBMonoid a
44− => Col context ('Spec labels 'Required db a)
45− -> Expr a
65+type NonNullifiability :: K.Context -> Type
66+data NonNullifiability context where
67+ NField :: NonNullifiability (Field table)
68+ NResult :: NonNullifiability Result
4669
47− nullifier :: ()
48− => Expr Bool
49− -> SSpec ('Spec labels necessity db a)
50− -> Col context ('Spec labels necessity db a)
51− -> Col context ('Spec labels necessity db (Maybe db))
5270
53− unnullifier :: ()
54− => Expr Bool
55− -> SSpec ('Spec labels necessity db a)
56− -> Col context ('Spec labels necessity db (Maybe db))
57− -> Col context ('Spec labels necessity db a)
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
5880
5981
60−type NullifiableEq :: K.Context -> K.Context -> Constraint
61−class (a ~ b, Nullifiable b) => NullifiableEq a b
62−instance (a ~ b, Nullifiable b) => NullifiableEq a b
82+absurd :: Nullifiability context -> NonNullifiability context -> a
83+absurd = \case
84+ NAggregate -> \case
85+ NExpr -> \case
86+ NName -> \case
6387
6488
65−runTag :: Nullability db a -> Expr Bool -> Expr a -> Expr (Maybe db)
66−runTag nullability tag a = case nullability of
67− Nullable -> boolExpr null a tag
68− NonNullable -> boolExpr null (nullify a) tag
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
69131 where
70132 null = fromPrimExpr $ Opaleye.ConstExpr Opaleye.NullLit
71133
72134
73−unnull :: Nullability db a -> Expr (Maybe db) -> Expr a
74−unnull nullability a = case nullability of
75− Nullable -> a
76− NonNullable -> unsafeUnnullify a
135+snullify :: Nullity a -> Expr a -> Expr (Nullify a)
136+snullify nullity a = case nullity of
137+ Null -> a
138+ NotNull -> nullify a
139+
140+
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/Field.hs+37−21
@@ -1,34 +1,50 @@
11{-# language DataKinds #-}
2+{-# language FlexibleContexts #-}
3+{-# language MultiParamTypeClasses #-}
24{-# language StandaloneKindSignatures #-}
35{-# language TypeFamilies #-}
46
57module Rel8.Schema.Field
6− ( Field
8+ ( Field(..)
9+ , fields
710 )
811where
912
1013-- base
11−import Data.Functor.Identity ( Identity )
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.Insert ( Insert )
21−import qualified Rel8.Schema.Kind as K
22−import Rel8.Schema.Spec ( Spec( Spec ) )
23−import Rel8.Schema.Structure ( Structure, Shape( Column ), Shape1 )
24−
25−
26−type Field :: K.Context -> Labels -> Necessity -> Type -> Type -> Type
27−type family Field labels context necessity db a where
28− Field Identity _labels _necessity _db a = a
29− Field Expr _labels _necessity _db a = Expr a
30− Field Insert _labels 'Required _db a = Expr a
31− Field Insert _labels 'Optional _db a = Maybe (Expr a)
32− Field Aggregate _labels _necessity _db a = Aggregate (Expr a)
33− Field Structure labels necessity db a = Shape1 'Column ('Spec labels necessity db a)
34− Field context _labels _necessity _db a = context a
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
27+ )
28+import Rel8.Table.Transpose ( Transposes )
29+import Rel8.Type ( DBType )
30+
31+
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)
35+
36+
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−1049
@@ -1,1049 +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.Functor.Identity ( Identity )
27−import Data.Kind ( Constraint, Type )
28−import Data.List.NonEmpty ( NonEmpty )
29−import GHC.Generics
30− ( Generic, Rep, from, to
31− , (:*:)( (:*:) ), K1( K1 ), M1( M1 )
32− , D, C, S
33− , Meta( MetaSel )
34− )
35−import GHC.TypeLits ( Symbol, KnownSymbol )
36−import Prelude
37−
38−-- rel8
39−import Rel8.Aggregate ( Aggregate, Col(..) )
40−import Rel8.Expr ( Expr, Col(..) )
41−import Rel8.Kind.Necessity
42− ( SNecessity( SRequired, SOptional )
43− , KnownNecessity, necessitySing
44− )
45−import Rel8.Schema.Context ( Col(..) )
46−import Rel8.Schema.Context.Identity
47− ( fromHEitherTable, toHEitherTable
48− , fromHListTable, toHListTable
49− , fromHMaybeTable, toHMaybeTable
50− , fromHNonEmptyTable, toHNonEmptyTable
51− , fromHTheseTable, toHTheseTable
52− )
53−import Rel8.Schema.Context.Label
54− ( Labelable, labeler, unlabeler
55− , hlabeler, hunlabeler
56− )
57−import Rel8.Schema.Field ( Field )
58−import Rel8.Schema.HTable ( HTable )
59−import Rel8.Schema.HTable.Either ( HEitherTable )
60−import Rel8.Schema.HTable.Identity ( HIdentity(..) )
61−import Rel8.Schema.HTable.Label ( HLabel, hlabel, hunlabel )
62−import Rel8.Schema.HTable.List ( HListTable )
63−import Rel8.Schema.HTable.Maybe ( HMaybeTable )
64−import Rel8.Schema.HTable.NonEmpty ( HNonEmptyTable )
65−import Rel8.Schema.HTable.Pair ( HPair(..) )
66−import Rel8.Schema.HTable.Quartet ( HQuartet(..) )
67−import Rel8.Schema.HTable.Quintet ( HQuintet(..) )
68−import Rel8.Schema.HTable.These ( HTheseTable )
69−import Rel8.Schema.HTable.Trio ( HTrio(..) )
70−import Rel8.Schema.HTable.Vectorize ( hrelabel )
71−import Rel8.Schema.Insert ( Insert, Col(..) )
72−import qualified Rel8.Schema.Kind as K
73−import Rel8.Schema.Name ( Name( Name ), Col(..) )
74−import Rel8.Schema.Spec ( Spec( Spec ), KTable )
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 context) => Table context (t context) where
97− type Columns (t context) = GRep t
98− type Context (t context) = context
99− fromColumns = gfromColumns
100− toColumns = gtoColumns
101−
102−
103−type TableHelper :: K.Context -> Constraint
104−class TableHelper context where
105− gfromColumns :: Rel8able t => GRep t (Col context) -> t context
106− gtoColumns :: Rel8able t => t context -> GRep t (Col context)
107−
108−
109−instance TableHelper Aggregate where
110− gfromColumns = fromAggregateColumns
111− gtoColumns = toAggregateColumns
112−
113−
114−instance TableHelper Expr where
115− gfromColumns = fromExprColumns
116− gtoColumns = toExprColumns
117−
118−
119−instance TableHelper Insert where
120− gfromColumns = fromInsertColumns
121− gtoColumns = toInsertColumns
122−
123−
124−instance TableHelper Identity where
125− gfromColumns = fromIdentityColumns
126− gtoColumns = toIdentityColumns
127−
128−
129−instance TableHelper Name where
130− gfromColumns = fromNameColumns
131− gtoColumns = toNameColumns
132−
133−
134−-- | This type class allows you to define custom 'Table's using higher-kinded
135−-- data types. Higher-kinded data types are data types of the pattern:
136−--
137−-- @
138−-- data MyType f =
139−-- MyType { field1 :: Column f T1 OR HK1 f
140−-- , field2 :: Column f T2 OR HK2 f
141−-- , ...
142−-- , fieldN :: Column f Tn OR HKn f
143−-- }
144−-- @
145−--
146−-- where @Tn@ is any Haskell type, and @HKn@ is any higher-kinded type.
147−--
148−-- That is, higher-kinded data are records where all fields in the record are
149−-- all either of the type @Column f T@ (for any @T@), or are themselves
150−-- higher-kinded data:
151−--
152−-- [Nested]
153−--
154−-- @
155−-- data Nested f =
156−-- Nested { nested1 :: MyType f
157−-- , nested2 :: MyType f
158−-- }
159−-- @
160−--
161−-- The @Rel8able@ type class is used to give us a special mapping operation
162−-- that lets us change the type parameter @f@.
163−--
164−-- [Supplying @Rel8able@ instances]
165−--
166−-- This type class should be derived generically for all table types in your
167−-- project. To do this, enable the @DeriveAnyType@ and @DeriveGeneric@ language
168−-- extensions:
169−--
170−-- @
171−-- \{\-\# LANGUAGE DeriveAnyClass, DeriveGeneric #-\}
172−--
173−-- data MyType f = MyType { fieldA :: Column f T }
174−-- deriving ( GHC.Generics.Generic, Rel8able )
175−-- @
176−type Rel8able :: KTable -> Constraint
177−class HTable (GRep t) => Rel8able t where
178− type GRep t :: K.HTable
179−
180− fromAggregateColumns :: GRep t (Col Aggregate) -> t Aggregate
181− toAggregateColumns :: t Aggregate -> GRep t (Col Aggregate)
182−
183− fromExprColumns :: GRep t (Col Expr) -> t Expr
184− toExprColumns :: t Expr -> GRep t (Col Expr)
185−
186− fromInsertColumns :: GRep t (Col Insert) -> t Insert
187− toInsertColumns :: t Insert -> GRep t (Col Insert)
188−
189− fromIdentityColumns :: GRep t (Col Identity) -> t Identity
190− toIdentityColumns :: t Identity -> GRep t (Col Identity)
191−
192− fromNameColumns :: GRep t (Col Name) -> t Name
193− toNameColumns :: t Name -> GRep t (Col Name)
194−
195− type GRep t = GColumns (Rep (t Structure))
196−
197− default fromAggregateColumns ::
198− ( Generic (t Aggregate)
199− , GColumns (Rep (t Structure)) ~ GRep t
200− , GRel8able Aggregate (Rep (t Structure)) (Rep (t Aggregate))
201− ) => GRep t (Col Aggregate) -> t Aggregate
202− fromAggregateColumns = to . fromGColumns @_ @(Rep (t Structure))
203−
204− default toAggregateColumns ::
205− ( Generic (t Aggregate)
206− , GColumns (Rep (t Structure)) ~ GRep t
207− , GRel8able Aggregate (Rep (t Structure)) (Rep (t Aggregate))
208− ) => t Aggregate -> GRep t (Col Aggregate)
209− toAggregateColumns = toGColumns @_ @(Rep (t Structure)) . from
210−
211− default fromExprColumns ::
212− ( Generic (t Expr)
213− , GColumns (Rep (t Structure)) ~ GRep t
214− , GRel8able Expr (Rep (t Structure)) (Rep (t Expr))
215− ) => GRep t (Col Expr) -> t Expr
216− fromExprColumns = to . fromGColumns @_ @(Rep (t Structure))
217−
218− default toExprColumns ::
219− ( Generic (t Expr)
220− , GColumns (Rep (t Structure)) ~ GRep t
221− , GRel8able Expr (Rep (t Structure)) (Rep (t Expr))
222− ) => t Expr -> GRep t (Col Expr)
223− toExprColumns = toGColumns @_ @(Rep (t Structure)) . from
224−
225− default fromInsertColumns ::
226− ( Generic (t Insert)
227− , GColumns (Rep (t Structure)) ~ GRep t
228− , GRel8able Insert (Rep (t Structure)) (Rep (t Insert))
229− ) => GRep t (Col Insert) -> t Insert
230− fromInsertColumns = to . fromGColumns @_ @(Rep (t Structure))
231−
232− default toInsertColumns ::
233− ( Generic (t Insert)
234− , GColumns (Rep (t Structure)) ~ GRep t
235− , GRel8able Insert (Rep (t Structure)) (Rep (t Insert))
236− ) => t Insert -> GRep t (Col Insert)
237− toInsertColumns = toGColumns @_ @(Rep (t Structure)) . from
238−
239− default fromIdentityColumns ::
240− ( Generic (t Identity)
241− , GColumns (Rep (t Structure)) ~ GRep t
242− , GRel8able Identity (Rep (t Structure)) (Rep (t Identity))
243− ) => GRep t (Col Identity) -> t Identity
244− fromIdentityColumns = to . fromGColumns @_ @(Rep (t Structure))
245−
246− default toIdentityColumns ::
247− ( Generic (t Identity)
248− , GColumns (Rep (t Structure)) ~ GRep t
249− , GRel8able Identity (Rep (t Structure)) (Rep (t Identity))
250− ) => t Identity -> GRep t (Col Identity)
251− toIdentityColumns = toGColumns @_ @(Rep (t Structure)) . from
252−
253− default fromNameColumns ::
254− ( Generic (t Name)
255− , GColumns (Rep (t Structure)) ~ GRep t
256− , GRel8able Name (Rep (t Structure)) (Rep (t Name))
257− ) => GRep t (Col Name) -> t Name
258− fromNameColumns = to . fromGColumns @_ @(Rep (t Structure))
259−
260− default toNameColumns ::
261− ( Generic (t Name)
262− , GColumns (Rep (t Structure)) ~ GRep t
263− , GRel8able Name (Rep (t Structure)) (Rep (t Name))
264− ) => t Name -> GRep t (Col Name)
265− toNameColumns = toGColumns @_ @(Rep (t Structure)) . from
266−
267−
268−type GColumns :: (Type -> Type) -> K.HTable
269−type family GColumns structure where
270− GColumns (M1 D _ structure) = GColumns structure
271− GColumns (M1 C _ structure) = GColumns structure
272− GColumns (a :*: b) = HPair (GColumns a) (GColumns b)
273− GColumns (M1 S ('MetaSel ('Just label) _ _ _) (K1 _ structure)) =
274− K1Columns label structure
275−
276−
277−type GRel8able :: K.Context -> (Type -> Type) -> (Type -> Type) -> Constraint
278−class GRel8able context structure rep where
279− fromGColumns :: GColumns structure (Col context) -> rep x
280− toGColumns :: rep x -> GColumns structure (Col context)
281−
282−
283−instance GRel8able context structure rep => GRel8able context (M1 D c structure) (M1 D c rep) where
284− fromGColumns = M1 . fromGColumns @context @structure @rep
285− toGColumns (M1 a) = toGColumns @context @structure @rep a
286−
287−
288−instance GRel8able context structure rep => GRel8able context (M1 C c structure) (M1 C c rep) where
289− fromGColumns = M1 . fromGColumns @context @structure @rep
290− toGColumns (M1 a) = toGColumns @context @structure @rep a
291−
292−
293−instance (GRel8able context structure1 rep1, GRel8able context structure2 rep2) =>
294− GRel8able context (structure1 :*: structure2) (rep1 :*: rep2)
295− where
296− fromGColumns (HPair a b) =
297− fromGColumns @context @structure1 @rep1 a :*:
298− fromGColumns @context @structure2 @rep2 b
299− toGColumns (a :*: b) =
300− HPair
301− (toGColumns @context @structure1 @rep1 a)
302− (toGColumns @context @structure2 @rep2 b)
303−
304−
305−instance
306− ( K1Table label context isStructure structure a
307− , meta ~ 'MetaSel ('Just label) _su _ss _ds
308− , structureK1 ~ K1 i structure
309− , k1 ~ K1 i a
310− ) => GRel8able context (M1 S meta structureK1) (M1 S meta k1)
311− where
312− fromGColumns = M1 . K1 . fromK1Columns @label @_ @_ @structure
313− toGColumns (M1 (K1 a)) = toK1Columns @label @_ @_ @structure a
314−
315−
316−type K1Columns :: Symbol -> Type -> K.HTable
317−type family K1Columns label structure where
318− K1Columns label (Shape1 'Column ('Spec '[] necessity nullability blueprint)) =
319− HIdentity ('Spec '[label] necessity nullability blueprint)
320− K1Columns _label (Shape1 'Column ('Spec (label ': labels) necessity nullability blueprint)) =
321− HIdentity ('Spec (label ': labels) necessity nullability blueprint)
322− K1Columns label (Shape2 'Either a b) =
323− HLabel label (HEitherTable (K1Columns "Left" a) (K1Columns "Right" b))
324− K1Columns label (Shape1 'List a) = HListTable (K1Columns label a)
325− K1Columns label (Shape1 'Maybe a) = HLabel label (HMaybeTable (K1Columns "Just" a))
326− K1Columns label (Shape1 'NonEmpty a) = HNonEmptyTable (K1Columns label a)
327− K1Columns label (Shape2 'These a b) =
328− HLabel label (HTheseTable (K1Columns "Here" a) (K1Columns "There" b))
329− K1Columns label (a, b) =
330− HLabel label
331− (HPair
332− (K1Columns "fst" a)
333− (K1Columns "snd" b))
334− K1Columns label (a, b, c) =
335− HLabel label
336− (HTrio
337− (K1Columns "fst" a)
338− (K1Columns "snd" b)
339− (K1Columns "trd" c))
340− K1Columns label (a, b, c, d) =
341− HLabel label
342− (HQuartet
343− (K1Columns "fst" a)
344− (K1Columns "snd" b)
345− (K1Columns "trd" c)
346− (K1Columns "frt" d))
347− K1Columns label (a, b, c, d, e) =
348− HLabel label
349− (HQuintet
350− (K1Columns "fst" a)
351− (K1Columns "snd" b)
352− (K1Columns "trd" c)
353− (K1Columns "frt" d)
354− (K1Columns "fft" e))
355− K1Columns label a = HLabel label (Columns a)
356−
357−
358−type K1Table :: Symbol -> K.Context -> Bool -> Type -> Type -> Constraint
359−class isStructure ~ IsStructure structure =>
360− K1Table label context isStructure structure a
361− where
362− fromK1Columns :: K1Columns label structure (Col context) -> a
363− toK1Columns :: a -> K1Columns label structure (Col context)
364−
365−
366−instance
367− ( x ~ Field Aggregate '[] necessity db a
368− ) => K1Table label Aggregate 'True (Shape1 'Column ('Spec '[] necessity db a)) x
369− where
370− fromK1Columns (HIdentity (Aggregation a)) = a
371− toK1Columns = HIdentity . Aggregation
372− {-# INLINABLE fromK1Columns #-}
373− {-# INLINABLE toK1Columns #-}
374−
375−
376−instance
377− ( x ~ Field Aggregate (label ': labels) necessity db a
378− ) => K1Table _label Aggregate 'True (Shape1 'Column ('Spec (label ': labels) necessity db a)) x
379− where
380− fromK1Columns (HIdentity (Aggregation a)) = a
381− toK1Columns = HIdentity . Aggregation
382− {-# INLINABLE fromK1Columns #-}
383− {-# INLINABLE toK1Columns #-}
384−
385−
386−instance
387− ( x ~ Field Expr '[] necessity db a
388− ) => K1Table label Expr 'True (Shape1 'Column ('Spec '[] necessity db a)) x
389− where
390− fromK1Columns (HIdentity (DB a)) = a
391− toK1Columns = HIdentity . DB
392− {-# INLINABLE fromK1Columns #-}
393− {-# INLINABLE toK1Columns #-}
394−
395−
396−instance
397− ( x ~ Field Expr (label ': labels) necessity db a
398− ) => K1Table _label Expr 'True (Shape1 'Column ('Spec (label ': labels) necessity db a)) x
399− where
400− fromK1Columns (HIdentity (DB a)) = a
401− toK1Columns = HIdentity . DB
402− {-# INLINABLE fromK1Columns #-}
403− {-# INLINABLE toK1Columns #-}
404−
405−
406−instance
407− ( x ~ Field Insert '[] necessity db a
408− , KnownNecessity necessity
409− ) => K1Table label Insert 'True (Shape1 'Column ('Spec '[] necessity db a)) x
410− where
411− fromK1Columns (HIdentity insert) = case insert of
412− RequiredInsert a -> a
413− OptionalInsert ma -> ma
414− toK1Columns a = HIdentity $ case necessitySing @necessity of
415− SRequired -> RequiredInsert a
416− SOptional -> OptionalInsert a
417− {-# INLINABLE fromK1Columns #-}
418− {-# INLINABLE toK1Columns #-}
419−
420−
421−instance
422− ( x ~ Field Insert (label ': labels) necessity db a
423− , KnownNecessity necessity
424− ) => K1Table _label Insert 'True (Shape1 'Column ('Spec (label ': labels) necessity db a)) x
425− where
426− fromK1Columns (HIdentity insert) = case insert of
427− RequiredInsert a -> a
428− OptionalInsert ma -> ma
429− toK1Columns a = HIdentity $ case necessitySing @necessity of
430− SRequired -> RequiredInsert a
431− SOptional -> OptionalInsert a
432− {-# INLINABLE fromK1Columns #-}
433− {-# INLINABLE toK1Columns #-}
434−
435−
436−instance
437− ( x ~ Field Identity '[] necessity db a
438− ) => K1Table label Identity 'True (Shape1 'Column ('Spec '[] necessity db a)) x
439− where
440− fromK1Columns (HIdentity (Result a)) = a
441− toK1Columns = HIdentity . Result
442− {-# INLINABLE fromK1Columns #-}
443− {-# INLINABLE toK1Columns #-}
444−
445−
446−instance
447− ( x ~ Field Identity (label ': labels) necessity db a
448− ) => K1Table _label Identity 'True (Shape1 'Column ('Spec (label ': labels) necessity db a)) x
449− where
450− fromK1Columns (HIdentity (Result a)) = a
451− toK1Columns = HIdentity . Result
452− {-# INLINABLE fromK1Columns #-}
453− {-# INLINABLE toK1Columns #-}
454−
455−
456−instance
457− ( x ~ Field Name '[] necessity db a
458− ) => K1Table _label Name 'True (Shape1 'Column ('Spec (label ': labels) necessity db a)) x
459− where
460− fromK1Columns (HIdentity (NameCol a)) = Name a
461− toK1Columns (Name a) = HIdentity (NameCol a)
462− {-# INLINABLE fromK1Columns #-}
463− {-# INLINABLE toK1Columns #-}
464−
465−
466−instance
467− ( x ~ Field Name (label ': labels) necessity db a
468− ) => K1Table label Name 'True (Shape1 'Column ('Spec '[] necessity db a)) x
469− where
470− fromK1Columns = Name . (\(NameCol a) -> a) . unlabeler . unHIdentity
471− toK1Columns = HIdentity . labeler . NameCol . (\(Name a) -> a)
472− {-# INLINABLE fromK1Columns #-}
473− {-# INLINABLE toK1Columns #-}
474−
475−
476−instance
477− ( HTable (K1Columns "Left" structure1)
478− , HTable (K1Columns "Right" structure2)
479− , K1Table "Left" Aggregate (IsStructure structure1) structure1 a
480− , K1Table "Right" Aggregate (IsStructure structure2) structure2 b
481− , e ~ EitherTable a b
482− , KnownSymbol label
483− ) => K1Table label Aggregate 'True (Shape2 'Either structure1 structure2) e
484− where
485− fromK1Columns =
486− fromColumns2
487− (fromK1Columns @"Left" @_ @_ @structure1)
488− (fromK1Columns @"Right" @_ @_ @structure2) .
489− hunlabel unlabeler
490− toK1Columns =
491− hlabel labeler .
492− toColumns2
493− (toK1Columns @"Left" @_ @_ @structure1)
494− (toK1Columns @"Right" @_ @_ @structure2)
495− {-# INLINABLE fromK1Columns #-}
496− {-# INLINABLE toK1Columns #-}
497−
498−
499−instance
500− ( HTable (K1Columns "Left" structure1)
501− , HTable (K1Columns "Right" structure2)
502− , K1Table "Left" Expr (IsStructure structure1) structure1 a
503− , K1Table "Right" Expr (IsStructure structure2) structure2 b
504− , e ~ EitherTable a b
505− , KnownSymbol label
506− ) => K1Table label Expr 'True (Shape2 'Either structure1 structure2) e
507− where
508− fromK1Columns =
509− fromColumns2
510− (fromK1Columns @"Left" @_ @_ @structure1)
511− (fromK1Columns @"Right" @_ @_ @structure2) .
512− hunlabel unlabeler
513− toK1Columns =
514− hlabel labeler .
515− toColumns2
516− (toK1Columns @"Left" @_ @_ @structure1)
517− (toK1Columns @"Right" @_ @_ @structure2)
518− {-# INLINABLE fromK1Columns #-}
519− {-# INLINABLE toK1Columns #-}
520−
521−
522−instance
523− ( HTable (K1Columns "Left" structure1)
524− , HTable (K1Columns "Right" structure2)
525− , K1Table "Left" Insert (IsStructure structure1) structure1 a
526− , K1Table "Right" Insert (IsStructure structure2) structure2 b
527− , e ~ EitherTable a b
528− , KnownSymbol label
529− ) => K1Table label Insert 'True (Shape2 'Either structure1 structure2) e
530− where
531− fromK1Columns =
532− fromColumns2
533− (fromK1Columns @"Left" @_ @_ @structure1)
534− (fromK1Columns @"Right" @_ @_ @structure2) .
535− hunlabel unlabeler
536− toK1Columns =
537− hlabel labeler .
538− toColumns2
539− (toK1Columns @"Left" @_ @_ @structure1)
540− (toK1Columns @"Right" @_ @_ @structure2)
541− {-# INLINABLE fromK1Columns #-}
542− {-# INLINABLE toK1Columns #-}
543−
544−
545−instance
546− ( HTable (K1Columns "Left" structure1)
547− , HTable (K1Columns "Right" structure2)
548− , K1Table "Left" Identity (IsStructure structure1) structure1 a
549− , K1Table "Right" Identity (IsStructure structure2) structure2 b
550− , e ~ Either a b
551− , KnownSymbol label
552− ) => K1Table label Identity 'True (Shape2 'Either structure1 structure2) e
553− where
554− fromK1Columns
555− = bimap
556− (fromK1Columns @"Left" @_ @_ @structure1)
557− (fromK1Columns @"Right" @_ @_ @structure2)
558− . fromHEitherTable
559− . hunlabel unlabeler
560− toK1Columns
561− = hlabel labeler
562− . toHEitherTable
563− . bimap
564− (toK1Columns @"Left" @_ @_ @structure1)
565− (toK1Columns @"Right" @_ @_ @structure2)
566− {-# INLINABLE fromK1Columns #-}
567− {-# INLINABLE toK1Columns #-}
568−
569−
570−instance
571− ( HTable (K1Columns "Left" structure1)
572− , HTable (K1Columns "Right" structure2)
573− , K1Table "Left" Name (IsStructure structure1) structure1 a
574− , K1Table "Right" Name (IsStructure structure2) structure2 b
575− , e ~ EitherTable a b
576− , KnownSymbol label
577− ) => K1Table label Name 'True (Shape2 'Either structure1 structure2) e
578− where
579− fromK1Columns =
580− fromColumns2
581− (fromK1Columns @"Left" @_ @_ @structure1)
582− (fromK1Columns @"Right" @_ @_ @structure2) .
583− hunlabel unlabeler
584− toK1Columns =
585− hlabel labeler .
586− toColumns2
587− (toK1Columns @"Left" @_ @_ @structure1)
588− (toK1Columns @"Right" @_ @_ @structure2)
589− {-# INLINABLE fromK1Columns #-}
590− {-# INLINABLE toK1Columns #-}
591−
592−
593−instance
594− ( Table Aggregate a
595− , K1Columns label structure ~ HLabel label (Columns a)
596− , as ~ ListTable a
597− , KnownSymbol label
598− ) => K1Table label Aggregate 'True (Shape1 'List structure) as
599− where
600− fromK1Columns = fromColumns . hrelabel (hunlabel hunlabeler)
601− toK1Columns = hrelabel (hlabel hlabeler) . toColumns
602− {-# INLINABLE fromK1Columns #-}
603− {-# INLINABLE toK1Columns #-}
604−
605−
606−instance
607− ( Table Expr a
608− , K1Columns label structure ~ HLabel label (Columns a)
609− , as ~ ListTable a
610− , KnownSymbol label
611− ) => K1Table label Expr 'True (Shape1 'List structure) as
612− where
613− fromK1Columns = fromColumns . hrelabel (hunlabel hunlabeler)
614− toK1Columns = hrelabel (hlabel hlabeler) . toColumns
615− {-# INLINABLE fromK1Columns #-}
616− {-# INLINABLE toK1Columns #-}
617−
618−
619−instance
620− ( Table Insert a
621− , K1Columns label structure ~ HLabel label (Columns a)
622− , as ~ ListTable a
623− , KnownSymbol label
624− ) => K1Table label Insert 'True (Shape1 'List structure) as
625− where
626− fromK1Columns = fromColumns . hrelabel (hunlabel hunlabeler)
627− toK1Columns = hrelabel (hlabel hlabeler) . toColumns
628− {-# INLINABLE fromK1Columns #-}
629− {-# INLINABLE toK1Columns #-}
630−
631−
632−instance
633− ( K1Table label Identity (IsStructure structure) structure a
634− , HTable (K1Columns label structure)
635− , as ~ [a]
636− ) => K1Table label Identity 'True (Shape1 'List structure) as
637− where
638− fromK1Columns = fmap (fromK1Columns @label @_ @_ @structure) . fromHListTable
639− toK1Columns = toHListTable . fmap (toK1Columns @label @_ @_ @structure)
640− {-# INLINABLE fromK1Columns #-}
641− {-# INLINABLE toK1Columns #-}
642−
643−
644−instance
645− ( Table Name a
646− , K1Columns label structure ~ HLabel label (Columns a)
647− , as ~ ListTable a
648− , KnownSymbol label
649− ) => K1Table label Name 'True (Shape1 'List structure) as
650− where
651− fromK1Columns = fromColumns . hrelabel (hunlabel hunlabeler)
652− toK1Columns = hrelabel (hlabel hlabeler) . toColumns
653− {-# INLINABLE fromK1Columns #-}
654− {-# INLINABLE toK1Columns #-}
655−
656−
657−instance
658− ( HTable (K1Columns "Just" structure)
659− , K1Table "Just" Aggregate (IsStructure structure) structure a
660− , ma ~ MaybeTable a
661− , KnownSymbol label
662− ) => K1Table label Aggregate 'True (Shape1 'Maybe structure) ma
663− where
664− fromK1Columns =
665− fromColumns1 (fromK1Columns @"Just" @_ @_ @structure) .
666− hunlabel unlabeler
667− toK1Columns =
668− hlabel labeler .
669− toColumns1 (toK1Columns @"Just" @_ @_ @structure)
670− {-# INLINABLE fromK1Columns #-}
671− {-# INLINABLE toK1Columns #-}
672−
673−
674−instance
675− ( HTable (K1Columns "Just" structure)
676− , K1Table "Just" Expr (IsStructure structure) structure a
677− , ma ~ MaybeTable a
678− , KnownSymbol label
679− ) => K1Table label Expr 'True (Shape1 'Maybe structure) ma
680− where
681− fromK1Columns =
682− fromColumns1 (fromK1Columns @"Just" @_ @_ @structure) .
683− hunlabel unlabeler
684− toK1Columns =
685− hlabel labeler .
686− toColumns1 (toK1Columns @"Just" @_ @_ @structure)
687− {-# INLINABLE fromK1Columns #-}
688− {-# INLINABLE toK1Columns #-}
689−
690−
691−instance
692− ( HTable (K1Columns "Just" structure)
693− , K1Table "Just" Insert (IsStructure structure) structure a
694− , ma ~ MaybeTable a
695− , KnownSymbol label
696− ) => K1Table label Insert 'True (Shape1 'Maybe structure) ma
697− where
698− fromK1Columns =
699− fromColumns1 (fromK1Columns @"Just" @_ @_ @structure) .
700− hunlabel unlabeler
701− toK1Columns =
702− hlabel labeler .
703− toColumns1 (toK1Columns @"Just" @_ @_ @structure)
704− {-# INLINABLE fromK1Columns #-}
705− {-# INLINABLE toK1Columns #-}
706−
707−
708−instance
709− ( HTable (K1Columns "Just" structure)
710− , K1Table "Just" Identity (IsStructure structure) structure a
711− , ma ~ Maybe a
712− , KnownSymbol label
713− ) => K1Table label Identity 'True (Shape1 'Maybe structure) ma
714− where
715− fromK1Columns
716− = fmap (fromK1Columns @"Just" @_ @_ @structure)
717− . fromHMaybeTable
718− . hunlabel unlabeler
719− toK1Columns
720− = hlabel labeler
721− . toHMaybeTable
722− . fmap (toK1Columns @"Just" @_ @_ @structure)
723− {-# INLINABLE fromK1Columns #-}
724− {-# INLINABLE toK1Columns #-}
725−
726−
727−instance
728− ( HTable (K1Columns "Just" structure)
729− , K1Table "Just" Name (IsStructure structure) structure a
730− , ma ~ MaybeTable a
731− , KnownSymbol label
732− ) => K1Table label Name 'True (Shape1 'Maybe structure) ma
733− where
734− fromK1Columns =
735− fromColumns1 (fromK1Columns @"Just" @_ @_ @structure) .
736− hunlabel unlabeler
737− toK1Columns =
738− hlabel labeler .
739− toColumns1 (toK1Columns @"Just" @_ @_ @structure)
740− {-# INLINABLE fromK1Columns #-}
741− {-# INLINABLE toK1Columns #-}
742−
743−
744−instance
745− ( Table Aggregate a
746− , K1Columns label structure ~ HLabel label (Columns a)
747− , as ~ NonEmptyTable a
748− , KnownSymbol label
749− ) => K1Table label Aggregate 'True (Shape1 'NonEmpty structure) as
750− where
751− fromK1Columns = fromColumns . hrelabel (hunlabel hunlabeler)
752− toK1Columns = hrelabel (hlabel hlabeler) . toColumns
753− {-# INLINABLE fromK1Columns #-}
754− {-# INLINABLE toK1Columns #-}
755−
756−
757−instance
758− ( Table Expr a
759− , K1Columns label structure ~ HLabel label (Columns a)
760− , as ~ NonEmptyTable a
761− , KnownSymbol label
762− ) => K1Table label Expr 'True (Shape1 'NonEmpty structure) as
763− where
764− fromK1Columns = fromColumns . hrelabel (hunlabel hunlabeler)
765− toK1Columns = hrelabel (hlabel hlabeler) . toColumns
766− {-# INLINABLE fromK1Columns #-}
767− {-# INLINABLE toK1Columns #-}
768−
769−
770−instance
771− ( Table Insert a
772− , K1Columns label structure ~ HLabel label (Columns a)
773− , as ~ NonEmptyTable a
774− , KnownSymbol label
775− ) => K1Table label Insert 'True (Shape1 'NonEmpty structure) as
776− where
777− fromK1Columns = fromColumns . hrelabel (hunlabel hunlabeler)
778− toK1Columns = hrelabel (hlabel hlabeler) . toColumns
779− {-# INLINABLE fromK1Columns #-}
780− {-# INLINABLE toK1Columns #-}
781−
782−
783−instance
784− ( K1Table label Identity (IsStructure structure) structure a
785− , HTable (K1Columns label structure)
786− , as ~ NonEmpty a
787− ) => K1Table label Identity 'True (Shape1 'NonEmpty structure) as
788− where
789− fromK1Columns = fmap (fromK1Columns @label @_ @_ @structure) . fromHNonEmptyTable
790− toK1Columns = toHNonEmptyTable . fmap (toK1Columns @label @_ @_ @structure)
791− {-# INLINABLE fromK1Columns #-}
792− {-# INLINABLE toK1Columns #-}
793−
794−
795−instance
796− ( Table Name a
797− , K1Columns label structure ~ HLabel label (Columns a)
798− , as ~ NonEmptyTable a
799− , KnownSymbol label
800− ) => K1Table label Name 'True (Shape1 'NonEmpty structure) as
801− where
802− fromK1Columns = fromColumns . hrelabel (hunlabel hunlabeler)
803− toK1Columns = hrelabel (hlabel hlabeler) . toColumns
804− {-# INLINABLE fromK1Columns #-}
805− {-# INLINABLE toK1Columns #-}
806−
807−
808−instance
809− ( HTable (K1Columns "Here" structure1)
810− , HTable (K1Columns "There" structure2)
811− , K1Table "Here" Aggregate (IsStructure structure1) structure1 a
812− , K1Table "There" Aggregate (IsStructure structure2) structure2 b
813− , e ~ TheseTable a b
814− , KnownSymbol label
815− ) => K1Table label Aggregate 'True (Shape2 'These structure1 structure2) e
816− where
817− fromK1Columns =
818− fromColumns2
819− (fromK1Columns @"Here" @_ @_ @structure1)
820− (fromK1Columns @"There" @_ @_ @structure2) .
821− hunlabel unlabeler
822− toK1Columns =
823− hlabel labeler .
824− toColumns2
825− (toK1Columns @"Here" @_ @_ @structure1)
826− (toK1Columns @"There" @_ @_ @structure2)
827− {-# INLINABLE fromK1Columns #-}
828− {-# INLINABLE toK1Columns #-}
829−
830−
831−instance
832− ( HTable (K1Columns "Here" structure1)
833− , HTable (K1Columns "There" structure2)
834− , K1Table "Here" Expr (IsStructure structure1) structure1 a
835− , K1Table "There" Expr (IsStructure structure2) structure2 b
836− , e ~ TheseTable a b
837− , KnownSymbol label
838− ) => K1Table label Expr 'True (Shape2 'These structure1 structure2) e
839− where
840− fromK1Columns =
841− fromColumns2
842− (fromK1Columns @"Here" @_ @_ @structure1)
843− (fromK1Columns @"There" @_ @_ @structure2) .
844− hunlabel unlabeler
845− toK1Columns =
846− hlabel labeler .
847− toColumns2
848− (toK1Columns @"Here" @_ @_ @structure1)
849− (toK1Columns @"There" @_ @_ @structure2)
850− {-# INLINABLE fromK1Columns #-}
851− {-# INLINABLE toK1Columns #-}
852−
853−
854−instance
855− ( HTable (K1Columns "Here" structure1)
856− , HTable (K1Columns "There" structure2)
857− , K1Table "Here" Insert (IsStructure structure1) structure1 a
858− , K1Table "There" Insert (IsStructure structure2) structure2 b
859− , e ~ TheseTable a b
860− , KnownSymbol label
861− ) => K1Table label Insert 'True (Shape2 'These structure1 structure2) e
862− where
863− fromK1Columns =
864− fromColumns2
865− (fromK1Columns @"Here" @_ @_ @structure1)
866− (fromK1Columns @"There" @_ @_ @structure2) .
867− hunlabel unlabeler
868− toK1Columns =
869− hlabel labeler .
870− toColumns2
871− (toK1Columns @"Here" @_ @_ @structure1)
872− (toK1Columns @"There" @_ @_ @structure2)
873− {-# INLINABLE fromK1Columns #-}
874− {-# INLINABLE toK1Columns #-}
875−
876−
877−instance
878− ( HTable (K1Columns "Here" structure1)
879− , HTable (K1Columns "There" structure2)
880− , K1Table "Here" Identity (IsStructure structure1) structure1 a
881− , K1Table "There" Identity (IsStructure structure2) structure2 b
882− , e ~ These a b
883− , KnownSymbol label
884− ) => K1Table label Identity 'True (Shape2 'These structure1 structure2) e
885− where
886− fromK1Columns
887− = bimap
888− (fromK1Columns @"Here" @_ @_ @structure1)
889− (fromK1Columns @"There" @_ @_ @structure2)
890− . fromHTheseTable
891− . hunlabel unlabeler
892− toK1Columns
893− = hlabel labeler
894− . toHTheseTable
895− . bimap
896− (toK1Columns @"Here" @_ @_ @structure1)
897− (toK1Columns @"There" @_ @_ @structure2)
898− {-# INLINABLE fromK1Columns #-}
899− {-# INLINABLE toK1Columns #-}
900−
901−
902−instance
903− ( HTable (K1Columns "Here" structure1)
904− , HTable (K1Columns "There" structure2)
905− , K1Table "Here" Name (IsStructure structure1) structure1 a
906− , K1Table "There" Name (IsStructure structure2) structure2 b
907− , e ~ TheseTable a b
908− , KnownSymbol label
909− ) => K1Table label Name 'True (Shape2 'These structure1 structure2) e
910− where
911− fromK1Columns =
912− fromColumns2
913− (fromK1Columns @"Here" @_ @_ @structure1)
914− (fromK1Columns @"There" @_ @_ @structure2) .
915− hunlabel unlabeler
916− toK1Columns =
917− hlabel labeler .
918− toColumns2
919− (toK1Columns @"Here" @_ @_ @structure1)
920− (toK1Columns @"There" @_ @_ @structure2)
921− {-# INLINABLE fromK1Columns #-}
922− {-# INLINABLE toK1Columns #-}
923−
924−
925−instance
926− ( K1Table "fst" context (IsStructure structure1) structure1 a1
927− , K1Table "snd" context (IsStructure structure2) structure2 a2
928− , HTable (K1Columns "fst" structure1)
929− , HTable (K1Columns "snd" structure2)
930− , Labelable context
931− , a ~ (a1, a2)
932− , KnownSymbol label
933− ) => K1Table label context 'True (structure1, structure2) a
934− where
935− fromK1Columns (hunlabel unlabeler -> (HPair a b)) =
936− ( fromK1Columns @"fst" @_ @_ @structure1 a
937− , fromK1Columns @"snd" @_ @_ @structure2 b
938− )
939− toK1Columns (a, b) = hlabel labeler $ HPair
940− { hfst = toK1Columns @"fst" @_ @_ @structure1 a
941− , hsnd = toK1Columns @"snd" @_ @_ @structure2 b
942− }
943− {-# INLINABLE fromK1Columns #-}
944− {-# INLINABLE toK1Columns #-}
945−
946−
947−instance
948− ( K1Table "fst" context (IsStructure structure1) structure1 a1
949− , K1Table "snd" context (IsStructure structure2) structure2 a2
950− , K1Table "trd" context (IsStructure structure3) structure3 a3
951− , HTable (K1Columns "fst" structure1)
952− , HTable (K1Columns "snd" structure2)
953− , HTable (K1Columns "trd" structure3)
954− , Labelable context
955− , a ~ (a1, a2, a3)
956− , KnownSymbol label
957− ) => K1Table label context 'True (structure1, structure2, structure3) a
958− where
959− fromK1Columns (hunlabel unlabeler -> (HTrio a b c)) =
960− ( fromK1Columns @"fst" @_ @_ @structure1 a
961− , fromK1Columns @"snd" @_ @_ @structure2 b
962− , fromK1Columns @"trd" @_ @_ @structure3 c
963− )
964− toK1Columns (a, b, c) = hlabel labeler $ HTrio
965− { hfst = toK1Columns @"fst" @_ @_ @structure1 a
966− , hsnd = toK1Columns @"snd" @_ @_ @structure2 b
967− , htrd = toK1Columns @"trd" @_ @_ @structure3 c
968− }
969− {-# INLINABLE fromK1Columns #-}
970− {-# INLINABLE toK1Columns #-}
971−
972−
973−instance
974− ( K1Table "fst" context (IsStructure structure1) structure1 a1
975− , K1Table "snd" context (IsStructure structure2) structure2 a2
976− , K1Table "trd" context (IsStructure structure3) structure3 a3
977− , K1Table "frt" context (IsStructure structure3) structure4 a4
978− , HTable (K1Columns "fst" structure1)
979− , HTable (K1Columns "snd" structure2)
980− , HTable (K1Columns "trd" structure3)
981− , HTable (K1Columns "frt" structure4)
982− , Labelable context
983− , a ~ (a1, a2, a3, a4)
984− , KnownSymbol label
985− ) => K1Table label context 'True (structure1, structure2, structure3, structure4) a
986− where
987− fromK1Columns (hunlabel unlabeler -> (HQuartet a b c d)) =
988− ( fromK1Columns @"fst" @_ @_ @structure1 a
989− , fromK1Columns @"snd" @_ @_ @structure2 b
990− , fromK1Columns @"trd" @_ @_ @structure3 c
991− , fromK1Columns @"frt" @_ @_ @structure4 d
992− )
993− toK1Columns (a, b, c, d) = hlabel labeler $ HQuartet
994− { hfst = toK1Columns @"fst" @_ @_ @structure1 a
995− , hsnd = toK1Columns @"snd" @_ @_ @structure2 b
996− , htrd = toK1Columns @"trd" @_ @_ @structure3 c
997− , hfrt = toK1Columns @"frt" @_ @_ @structure4 d
998− }
999− {-# INLINABLE fromK1Columns #-}
1000− {-# INLINABLE toK1Columns #-}
1001−
1002−
1003−instance
1004− ( K1Table "fst" context (IsStructure structure1) structure1 a1
1005− , K1Table "snd" context (IsStructure structure2) structure2 a2
1006− , K1Table "trd" context (IsStructure structure3) structure3 a3
1007− , K1Table "frt" context (IsStructure structure3) structure4 a4
1008− , K1Table "fft" context (IsStructure structure3) structure5 a5
1009− , HTable (K1Columns "fst" structure1)
1010− , HTable (K1Columns "snd" structure2)
1011− , HTable (K1Columns "trd" structure3)
1012− , HTable (K1Columns "frt" structure4)
1013− , HTable (K1Columns "fft" structure5)
1014− , Labelable context
1015− , a ~ (a1, a2, a3, a4, a5)
1016− , KnownSymbol label
1017− ) => K1Table label context 'True (structure1, structure2, structure3, structure4, structure5) a
1018− where
1019− fromK1Columns (hunlabel unlabeler -> (HQuintet a b c d e)) =
1020− ( fromK1Columns @"fst" @_ @_ @structure1 a
1021− , fromK1Columns @"snd" @_ @_ @structure2 b
1022− , fromK1Columns @"trd" @_ @_ @structure3 c
1023− , fromK1Columns @"frt" @_ @_ @structure4 d
1024− , fromK1Columns @"fft" @_ @_ @structure5 e
1025− )
1026− toK1Columns (a, b, c, d, e) = hlabel labeler $ HQuintet
1027− { hfst = toK1Columns @"fst" @_ @_ @structure1 a
1028− , hsnd = toK1Columns @"snd" @_ @_ @structure2 b
1029− , htrd = toK1Columns @"trd" @_ @_ @structure3 c
1030− , hfrt = toK1Columns @"frt" @_ @_ @structure4 d
1031− , hfft = toK1Columns @"fft" @_ @_ @structure5 e
1032− }
1033− {-# INLINABLE fromK1Columns #-}
1034− {-# INLINABLE toK1Columns #-}
1035−
1036−
1037−instance
1038− ( IsStructure structure ~ 'False
1039− , K1Columns label structure ~ HLabel label (Columns structure)
1040− , Columns structure ~ Columns a
1041− , Labelable context
1042− , Table context a
1043− , KnownSymbol label
1044− ) => K1Table label context 'False structure a
1045− where
1046− fromK1Columns = fromColumns . hunlabel unlabeler
1047− toK1Columns = hlabel labeler . toColumns
1048− {-# INLINABLE fromK1Columns #-}
1049− {-# 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+68−38
@@ -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 )
@@ -34,16 +33,21 @@ 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 )
40−import Rel8.Schema.HTable.Pair ( HPair( HPair ) )
44+import Rel8.Schema.Spec ( Spec )
45+import Rel8.Schema.HTable.Product ( HProduct( HProduct ) )
4146import qualified Rel8.Schema.Kind as K
4247
4348-- semigroupoids
4449import Data.Functor.Apply ( Apply, (<.>) )
4550
46−
4751-- | A @HTable@ is a functor-indexed/higher-kinded data type that is
4852-- representable ('htabulate'/'hfield'), constrainable ('hdicts'), and
4953-- specified ('hspecs').
@@ -52,14 +56,14 @@ import Data.Functor.Apply ( Apply, (<.>) )
5256-- instances yourself or specify this constraint.
5357type HTable :: K.HTable -> Constraint
5458class HTable t where
55− type HField t = (field :: Spec -> Type) | field -> t
56− type HConstrainTable t (c :: Spec -> Constraint) :: Constraint
59+ type HField t = (field :: Type -> Type) | field -> t
60+ type HConstrainTable t (c :: Type -> Constraint) :: Constraint
5761
58− hfield :: t context -> HField t spec -> context spec
59− htabulate :: (forall spec. HField t spec -> context spec) -> t context
60− htraverse :: Apply m => (forall spec. f spec -> m (g spec)) -> t f -> m (t g)
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)
6165 hdicts :: HConstrainTable t c => t (Dict c)
62− hspecs :: t SSpec
66+ hspecs :: t Spec
6367
6468 type HField t = GHField t
6569 type HConstrainTable t c = HConstrainTable (GHColumns (Rep (t Proxy))) c
@@ -70,7 +74,7 @@ class HTable t where
7074 , HField (GHColumns (Rep (t Proxy))) ~ HField (GHColumns (Rep (t context)))
7175 , GHTable context (Rep (t context))
7276 )
73− => t context -> HField t spec -> context spec
77+ => t context -> HField t a -> context a
7478 hfield table (GHField field) = hfield (toGHColumns (from table)) field
7579
7680 default htabulate ::
@@ -79,7 +83,7 @@ class HTable t where
7983 , HField (GHColumns (Rep (t Proxy))) ~ HField (GHColumns (Rep (t context)))
8084 , GHTable context (Rep (t context))
8185 )
82− => (forall spec. HField t spec -> context spec) -> t context
86+ => (forall a. HField t a -> context a) -> t context
8387 htabulate f = to $ fromGHColumns $ htabulate (f . GHField)
8488
8589 default htraverse
@@ -89,7 +93,7 @@ class HTable t where
8993 , Generic (t g), GHTable g (Rep (t g))
9094 , GHColumns (Rep (t f)) ~ GHColumns (Rep (t g))
9195 )
92− => (forall spec. f spec -> m (g spec)) -> t f -> m (t g)
96+ => (forall a. f a -> m (g a)) -> t f -> m (t g)
9397 htraverse f = fmap (to . fromGHColumns) . htraverse f . toGHColumns . from
9498
9599 default hdicts
@@ -103,10 +107,10 @@ class HTable t where
103107 hdicts = to $ fromGHColumns (hdicts @(GHColumns (Rep (t Proxy))) @c)
104108
105109 default hspecs ::
106− ( Generic (t SSpec)
107− , GHTable SSpec (Rep (t SSpec))
110+ ( Generic (t Spec)
111+ , GHTable Spec (Rep (t Spec))
108112 )
109− => t SSpec
113+ => t Spec
110114 hspecs = to $ fromGHColumns hspecs
111115
112116 {-# INLINABLE hfield #-}
@@ -116,17 +120,43 @@ class HTable t where
116120 {-# INLINABLE hspecs #-}
117121
118122
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+
119133htabulateA :: (HTable t, Apply m)
120− => (forall spec. HField t spec -> m (context spec)) -> m (t context)
134+ => (forall a. HField t a -> m (context a)) -> m (t context)
121135htabulateA f = htraverse getCompose $ htabulate $ Compose . f
122136{-# INLINABLE htabulateA #-}
123137
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)
124154
125−type GHField :: K.HTable -> Spec -> Type
126−newtype GHField t spec = GHField (HField (GHColumns (Rep (t Proxy))) spec)
155+type GHField :: K.HTable -> Type -> Type
156+newtype GHField t a = GHField (HField (GHColumns (Rep (t Proxy))) a)
127157
128158
129−type GHTable :: K.HContext -> (Type -> Type) -> Constraint
159+type GHTable :: K.Context -> (Type -> Type) -> Constraint
130160class HTable (GHColumns rep) => GHTable context rep | rep -> context where
131161 type GHColumns rep :: K.HTable
132162 toGHColumns :: rep x -> GHColumns rep context
@@ -146,30 +176,30 @@ instance HTable table => GHTable context (K1 i (table context)) where
146176
147177
148178instance (GHTable context a, GHTable context b) => GHTable context (a :*: b) where
149− type GHColumns (a :*: b) = HPair (GHColumns a) (GHColumns b)
150− toGHColumns (a :*: b) = HPair (toGHColumns a) (toGHColumns b)
151− 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
152182
153183
154−-- | A HField type for indexing into HPair.
155−type HPairField :: K.HTable -> K.HTable -> Spec -> Type
156−data HPairField x y spec
157− = HFst (HField x spec)
158− | 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)
159189
160190
161−instance (HTable x, HTable y) => HTable (HPair x y) where
162− type HConstrainTable (HPair x y) c = (HConstrainTable x c, HConstrainTable y c)
163− 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
164194
165− hfield (HPair l r) = \case
195+ hfield (HProduct l r) = \case
166196 HFst i -> hfield l i
167197 HSnd i -> hfield r i
168198
169− htabulate f = HPair (htabulate (f . HFst)) (htabulate (f . HSnd))
170− htraverse f (HPair x y) = HPair <$> htraverse f x <.> htraverse f y
171− hdicts = HPair hdicts hdicts
172− hspecs = HPair hspecs hspecs
199+ htabulate f = HProduct (htabulate (f . HFst)) (htabulate (f . HSnd))
200+ htraverse f (HProduct x y) = HProduct <$> htraverse f x <.> htraverse f y
201+ hdicts = HProduct hdicts hdicts
202+ hspecs = HProduct hspecs hspecs
173203
174204 {-# INLINABLE hfield #-}
175205 {-# INLINABLE htabulate #-}
src/Rel8/Schema/HTable/Either.hs+5−6
@@ -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.Identity ( HIdentity(..) )
18+import Rel8.Schema.HTable.Identity ( HIdentity )
19+import Rel8.Schema.HTable.Label ( HLabel )
2020import Rel8.Schema.HTable.Nullify ( HNullify )
2121import qualified Rel8.Schema.Kind as K
22−import Rel8.Schema.Spec ( Spec( Spec ) )
2322import Rel8.Type.Tag ( EitherTag )
2423
2524
2625type 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+16−17
@@ -1,15 +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
1213import Data.Kind ( Type )
14+import Data.Type.Equality ( (:~:)( Refl ) )
1315import Prelude
1416
1517-- rel8
@@ -19,26 +21,23 @@ import Rel8.Schema.HTable
1921 , hfield, htabulate, htraverse, hdicts, hspecs
2022 )
2123import qualified Rel8.Schema.Kind as K
22−import Rel8.Schema.Spec ( Spec, KnownSpec, specSing )
24+import Rel8.Schema.Null ( Sql )
25+import Rel8.Schema.Spec ( specification )
26+import Rel8.Type ( DBType )
2327
2428
25−type HIdentity :: Spec -> K.HTable
26−newtype HIdentity spec context = HIdentity
27− { unHIdentity :: context spec
29+type HIdentity :: Type -> K.HTable
30+newtype HIdentity a context = HIdentity
31+ { unHIdentity :: context a
2832 }
2933
3034
31−type HIdentityField :: Spec -> Spec -> Type
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+36−51
@@ -1,85 +1,70 @@
1−{-# LANGUAGE DeriveAnyClass #-}
2−{-# LANGUAGE DeriveGeneric #-}
3−{-# LANGUAGE DerivingStrategies #-}
4−{-# LANGUAGE LambdaCase #-}
5−{-# language ConstraintKinds #-}
61{-# language DataKinds #-}
7−{-# language FlexibleInstances #-}
8−{-# language GADTs #-}
9−{-# language InstanceSigs #-}
10−{-# language MultiParamTypeClasses #-}
11−{-# language QuantifiedConstraints #-}
122{-# language RankNTypes #-}
133{-# language RecordWildCards #-}
144{-# language ScopedTypeVariables #-}
155{-# language StandaloneKindSignatures #-}
166{-# language TypeApplications #-}
177{-# language TypeFamilies #-}
18−{-# language TypeOperators #-}
19−{-# language UndecidableInstances #-}
208
219module Rel8.Schema.HTable.Label
22− ( HLabel
23− , hlabel, hunlabel
10+ ( HLabel, hlabel, hrelabel, hunlabel
11+ , hproject
2412 )
2513where
2614
2715-- base
16+import Data.Kind ( Type )
2817import Data.Proxy ( Proxy( Proxy ) )
29−import GHC.TypeLits ( KnownSymbol, Symbol )
18+import GHC.TypeLits ( KnownSymbol, Symbol, symbolVal )
3019import Prelude
3120
3221-- rel8
33−import Rel8.Kind.Labels ( SLabels( SLabels ) )
3422import Rel8.Schema.HTable
35− ( HTable
36− , hfield, htabulate, hspecs
23+ ( HTable, HConstrainTable, HField
24+ , htabulate, hfield, htraverse, hdicts, hspecs
3725 )
3826import qualified Rel8.Schema.Kind as K
39−import Rel8.Schema.Spec ( Spec( Spec ), SSpec(..) )
40−import Rel8.FCF
41−import Rel8.Schema.HTable.MapTable
42−import GHC.Generics (Generic)
27+import Rel8.Schema.Spec ( Spec(..) )
4328
4429
4530type HLabel :: Symbol -> K.HTable -> K.HTable
46−newtype HLabel label table context = HLabel (HMapTable (Label label) table context)
47− deriving stock Generic
48− deriving anyclass HTable
31+newtype HLabel label table context = HLabel (table context)
4932
5033
51−data Label :: Symbol -> Spec -> Exp Spec
34+type HLabelField :: Symbol -> K.HTable -> Type -> Type
35+newtype HLabelField label table a = HLabelField (HField table a)
5236
5337
54−type instance Eval (Label label ('Spec labels necessity db a)) = 'Spec (label : labels) necessity db a
38+instance (HTable table, KnownSymbol label) => HTable (HLabel label table) where
39+ type HField (HLabel label table) = HLabelField label table
40+ type HConstrainTable (HLabel label table) constraint =
41+ HConstrainTable table constraint
5542
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, ..}
49+ {-# INLINABLE hspecs #-}
5650
57−instance KnownSymbol l => MapSpec (Label l) where
58− mapInfo = \case
59− SSpec {..} -> SSpec {labels = SLabels Proxy labels, ..}
6051
61−
62−hlabel :: (HTable t, KnownSymbol label)
63− => (forall labels necessity db a. ()
64− => context ('Spec labels necessity db a)
65− -> context ('Spec (label ': labels) necessity db a))
66− -> t context
67− -> HLabel label t context
68−hlabel labeler a = HLabel $ htabulate $ \(HMapTableField field) ->
69− case hfield hspecs field of
70− SSpec {} -> labeler (hfield a field)
52+hlabel :: forall label t context. t context -> HLabel label t context
53+hlabel = HLabel
7154{-# INLINABLE hlabel #-}
7255
7356
74−hunlabel :: (HTable t, KnownSymbol label)
75− => (forall labels necessity db a. ()
76− => context ('Spec (label ': labels) necessity db a)
77− -> context ('Spec labels necessity db a))
78− -> HLabel label t context
79− -> t context
80−hunlabel unlabler (HLabel as) =
81− htabulate $ \field ->
82− case hfield hspecs field of
83− SSpec {} -> case hfield as (HMapTableField field) of
84− a -> unlabler a
57+hrelabel :: forall label' label t context. HLabel label t context -> HLabel label' t context
58+hrelabel = hlabel . hunlabel
59+{-# INLINABLE hrelabel #-}
60+
61+
62+hunlabel :: forall label t context. HLabel label t context -> t context
63+hunlabel (HLabel a) = a
8564{-# INLINABLE hunlabel #-}
65+
66+
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/MapTable.hs+35−15
@@ -6,7 +6,7 @@
66{-# language GADTs #-}
77{-# language InstanceSigs #-}
88{-# language MultiParamTypeClasses #-}
9−{-# language PolyKinds #-}
9+{-# language RankNTypes #-}
1010{-# language ScopedTypeVariables #-}
1111{-# language StandaloneKindSignatures #-}
1212{-# language TypeApplications #-}
@@ -14,31 +14,43 @@
1414{-# language UndecidableInstances #-}
1515{-# language UndecidableSuperClasses #-}
1616
17−module Rel8.Schema.HTable.MapTable ( HMapTable(..), MapSpec(..), Precompose(..), HMapTableField(..) ) where
17+module Rel8.Schema.HTable.MapTable
18+ ( HMapTable(..)
19+ , MapSpec(..)
20+ , Precompose(..)
21+ , HMapTableField(..)
22+ , hproject
23+ )
24+where
1825
1926-- base
2027import Data.Kind ( Constraint, Type )
21−import Prelude ( ($), (.), (<$>), fmap )
28+import Prelude
2229
2330-- rel8
24−import Rel8.FCF
31+import Rel8.FCF ( Exp, Eval )
2532import Rel8.Schema.HTable
26−import Rel8.Schema.Spec ( Spec, SSpec )
33+ ( HTable, HConstrainTable, HField
34+ , hfield, htabulate, htraverse, hdicts, hspecs
35+ )
36+import Rel8.Schema.Spec ( Spec )
2737import qualified Rel8.Schema.Kind as K
2838import Rel8.Schema.Dict ( Dict( Dict ) )
2939
3040
31−type HMapTable :: (a -> Exp b) -> ((a -> Type) -> Type) -> (b -> Type) -> Type
32−data HMapTable f t g where
33− HMapTable :: { unHMapTable :: t (Precompose f g) } -> HMapTable f t g
41+type HMapTable :: (Type -> Exp Type) -> K.HTable -> K.HTable
42+newtype HMapTable f t context = HMapTable
43+ { unHMapTable :: t (Precompose f context)
44+ }
3445
3546
36−type Precompose :: (a -> Exp b) -> (b -> Type) -> a -> Type
37−newtype Precompose f g x where
38− Precompose :: { precomposed :: g (Eval (f x)) } -> Precompose f g x
47+type Precompose :: (Type -> Exp Type) -> K.Context -> K.Context
48+newtype Precompose f g x = Precompose
49+ { precomposed :: g (Eval (f x))
50+ }
3951
4052
41−type HMapTableField :: (Spec -> Exp a) -> K.HTable -> a -> Type
53+type HMapTableField :: (Type -> Exp Type) -> K.HTable -> K.Context
4254data HMapTableField f t x where
4355 HMapTableField :: HField t a -> HMapTableField f t (Eval (f a))
4456
@@ -58,6 +70,7 @@ instance (HTable t, MapSpec f) => HTable (HMapTable f t) where
5870
5971 htraverse f (HMapTable x) =
6072 HMapTable <$> htraverse (fmap Precompose . f . precomposed) x
73+ {-# INLINABLE htraverse #-}
6174
6275 hdicts :: forall c. HConstrainTable (HMapTable f t) c => HMapTable f t (Dict c)
6376 hdicts =
@@ -67,13 +80,20 @@ instance (HTable t, MapSpec f) => HTable (HMapTable f t) where
6780
6881 hspecs =
6982 HMapTable $ htabulate $ Precompose . mapInfo @f . hfield hspecs
83+ {-# INLINABLE hspecs #-}
7084
7185
72−type MapSpec :: (Spec -> Exp Spec) -> Constraint
86+type MapSpec :: (Type -> Exp Type) -> Constraint
7387class MapSpec f where
74− mapInfo :: SSpec x -> SSpec (Eval (f x))
88+ mapInfo :: Spec x -> Spec (Eval (f x))
7589
7690
77−type ComposeConstraint :: (a -> Exp b) -> (b -> Constraint) -> a -> Constraint
91+type ComposeConstraint :: (Type -> Exp Type) -> (Type -> Constraint) -> Type -> Constraint
7892class c (Eval (f a)) => ComposeConstraint f c a
7993instance 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+5−10
@@ -1,7 +1,3 @@
1−{-# LANGUAGE NamedFieldPuns #-}
2−{-# LANGUAGE LambdaCase #-}
3−{-# LANGUAGE TypeFamilies #-}
4−{-# LANGUAGE KindSignatures #-}
51{-# language DataKinds #-}
62{-# language DeriveAnyClass #-}
73{-# language DeriveGeneric #-}
@@ -18,19 +14,18 @@ import GHC.Generics ( Generic )
1814import Prelude
1915
2016-- rel8
21−import Rel8.Kind.Necessity ( Necessity( Required ) )
2217import Rel8.Schema.HTable ( HTable )
23−import Rel8.Schema.HTable.Identity ( HIdentity(..) )
18+import Rel8.Schema.HTable.Identity ( HIdentity )
19+import Rel8.Schema.HTable.Label ( HLabel )
20+import Rel8.Schema.HTable.Nullify ( HNullify )
2421import qualified Rel8.Schema.Kind as K
25−import Rel8.Schema.Spec ( Spec( Spec ) )
2622import Rel8.Type.Tag ( MaybeTag )
27−import Rel8.Schema.HTable.Nullify ( HNullify )
2823
2924
3025type HMaybeTable :: K.HTable -> K.HTable
3126data HMaybeTable table context = HMaybeTable
32− { htag :: HIdentity ('Spec '["isJust"] 'Required MaybeTag (Maybe MaybeTag)) context
33− , hjust :: HNullify table context
27+ { htag :: HLabel "isJust" (HIdentity (Maybe MaybeTag)) context
28+ , hjust :: HLabel "Just" (HNullify table) context
3429 }
3530 deriving stock Generic
3631 deriving anyclass HTable
src/Rel8/Schema/HTable/Nullify.hs+55−45
@@ -1,47 +1,52 @@
1−{-# LANGUAGE DeriveAnyClass #-}
2−{-# LANGUAGE DerivingStrategies #-}
3−{-# LANGUAGE DeriveGeneric #-}
4−{-# LANGUAGE NamedFieldPuns #-}
5−{-# LANGUAGE LambdaCase #-}
61{-# language ConstraintKinds #-}
72{-# language DataKinds #-}
3+{-# language DeriveAnyClass #-}
4+{-# language DerivingStrategies #-}
5+{-# language DeriveGeneric #-}
86{-# language FlexibleInstances #-}
97{-# language GADTs #-}
10−{-# language InstanceSigs #-}
8+{-# language LambdaCase #-}
119{-# language MultiParamTypeClasses #-}
10+{-# language NamedFieldPuns #-}
1211{-# language QuantifiedConstraints #-}
1312{-# language RankNTypes #-}
1413{-# language RecordWildCards #-}
1514{-# language ScopedTypeVariables #-}
1615{-# language StandaloneKindSignatures #-}
17−{-# language TypeApplications #-}
1816{-# language TypeFamilies #-}
1917{-# language UndecidableInstances #-}
2018
2119module Rel8.Schema.HTable.Nullify
2220 ( HNullify( HNullify )
2321 , Nullify
24− , hnulls, hnullify, hunnullify
22+ , hguard
23+ , hnulls
24+ , hnullify
25+ , hunnullify
26+ , hproject
2527 )
2628where
2729
2830-- base
31+import Data.Kind ( Type )
32+import GHC.Generics ( Generic )
2933import Prelude hiding ( null )
3034
3135-- rel8
32−import Rel8.Schema.HTable
33− ( HTable
34− , hfield, htabulate, htabulateA, 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
3541 )
42+import qualified Rel8.Schema.HTable.MapTable as HMapTable ( hproject )
3643import qualified Rel8.Schema.Kind as K
37−import Rel8.Schema.Nullability ( Nullability( Nullable, NonNullable ) )
38−import Rel8.Schema.Spec ( Spec( Spec ), SSpec(..) )
44+import Rel8.Schema.Null ( Nullity( Null, NotNull ) )
45+import qualified Rel8.Schema.Null as Type ( Nullify )
46+import Rel8.Schema.Spec ( Spec(..) )
3947
4048-- semigroupoids
4149import Data.Functor.Apply ( Apply )
42−import Rel8.Schema.HTable.MapTable
43−import Rel8.FCF
44−import GHC.Generics (Generic)
4550
4651
4752type HNullify :: K.HTable -> K.HTable
@@ -50,58 +55,63 @@ newtype HNullify table context = HNullify (HMapTable Nullify table context)
5055 deriving anyclass HTable
5156
5257
53−
54−-- | Transform a 'Spec' by allowing it to be @null@.
55−data Nullify :: Spec -> Exp Spec
56−
57−
58−type instance Eval (Nullify ('Spec labels necessity dbType _)) =
59− '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
6061
6162
6263instance MapSpec Nullify where
6364 mapInfo = \case
64− SSpec{labels, necessity, info, nullability} -> SSpec
65− { labels
66− , necessity
67− , info
68− , nullability = case nullability of
69− Nullable -> Nullable
70− NonNullable -> Nullable
71− }
65+ Spec {nullity, ..} -> Spec
66+ { nullity = case nullity of
67+ Null -> Null
68+ NotNull -> Null
69+ , ..
70+ }
71+
72+
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
7282
7383
7484hnulls :: HTable t
75− => (forall labels necessity dbType. ()
76− => context ('Spec labels necessity dbType (Maybe dbType)))
85+ => (forall a. Spec a -> context (Type.Nullify a))
7786 -> HNullify t context
78−hnulls null = HNullify $ htabulate $ \(HMapTableField field) -> case hfield hspecs field of
79− SSpec {} -> null
87+hnulls null = HNullify $ htabulate $ \(HMapTableField field) ->
88+ case hfield hspecs field of
89+ spec@Spec {} -> null spec
8090{-# INLINABLE hnulls #-}
8191
8292
8393hnullify :: HTable t
84− => (forall labels necessity dbType a. ()
85− => SSpec ('Spec labels necessity dbType a)
86− -> context ('Spec labels necessity dbType a)
87− -> context ('Spec labels necessity dbType (Maybe dbType)))
94+ => (forall a. Spec a -> context a -> context (Type.Nullify a))
8895 -> t context
8996 -> HNullify t context
9097hnullify nullifier a = HNullify $ htabulate $ \(HMapTableField field) ->
9198 case hfield hspecs field of
92− spec@SSpec {} -> nullifier spec (hfield a field)
99+ spec@Spec {} -> nullifier spec (hfield a field)
93100{-# INLINABLE hnullify #-}
94101
95102
96103hunnullify :: (HTable t, Apply m)
97− => (forall labels necessity dbType a. ()
98− => SSpec ('Spec labels necessity dbType a)
99− -> context ('Spec labels necessity dbType (Maybe dbType))
100− -> m (context ('Spec labels necessity dbType a)))
104+ => (forall a. Spec a -> context (Type.Nullify a) -> m (context a))
101105 -> HNullify t context
102106 -> m (t context)
103107hunnullify unnullifier (HNullify as) =
104108 htabulateA $ \field -> case hfield hspecs field of
105− spec@SSpec {} -> case hfield as (HMapTableField field) of
109+ spec@Spec {} -> case hfield as (HMapTableField field) of
106110 a -> unnullifier spec a
107111{-# 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 qualified Rel8.Schema.Kind as K
14−
15−
16−type HPair :: K.HTable -> K.HTable -> K.HTable
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 qualified Rel8.Schema.Kind as K
19−
20−
21−type HQuartet :: K.HTable -> K.HTable -> K.HTable -> K.HTable -> K.HTable
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 qualified Rel8.Schema.Kind as K
19−
20−
21−type HQuintet :: K.HTable -> K.HTable -> K.HTable -> K.HTable -> K.HTable -> K.HTable
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+5−6
@@ -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 )
1918import Rel8.Schema.HTable.Identity ( HIdentity )
19+import Rel8.Schema.HTable.Label ( HLabel )
2020import Rel8.Schema.HTable.Nullify ( HNullify )
2121import qualified Rel8.Schema.Kind as K
22−import Rel8.Schema.Spec ( Spec( Spec ) )
2322import Rel8.Type.Tag ( MaybeTag )
2423
2524
2625type 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 qualified Rel8.Schema.Kind as K
19−
20−
21−type HTrio :: K.HTable -> K.HTable -> K.HTable -> K.HTable
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−55
@@ -1,55 +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 qualified Rel8.Schema.Kind as K
26−import Rel8.Schema.Nullability ( Unnullify, Sql, nullabilization )
27−import Rel8.Schema.Spec ( Spec( Spec ), SSpec(..) )
28−import Rel8.Type ( DBType, typeInformation )
29−
30−
31−type HType :: Type -> K.HTable
32−newtype HType a context = HType
33− { unHType :: context ('Spec '[""] 'Required (Unnullify a) a)
34− }
35−
36−
37−type HTypeField :: Type -> Spec -> Type
38−data HTypeField a spec where
39− HTypeField :: HTypeField a ('Spec '[""] 'Required (Unnullify a) a)
40−
41−
42−instance Sql DBType a => HTable (HType a) where
43− type HConstrainTable (HType a) c = c ('Spec '[""] 'Required (Unnullify a) a)
44− type HField (HType a) = HTypeField a
45−
46− hfield (HType a) HTypeField = a
47− htabulate f = HType $ f HTypeField
48− htraverse f (HType a) = HType <$> f a
49− hdicts = HType Dict
50− hspecs = HType SSpec
51− { labels = SLabel Proxy
52− , necessity = SRequired
53− , info = typeInformation
54− , nullability = nullabilization
55− }
src/Rel8/Schema/HTable/Vectorize.hs+51−69
@@ -1,74 +1,74 @@
1−{-# LANGUAGE DeriveAnyClass #-}
2−{-# LANGUAGE DeriveGeneric #-}
3−{-# LANGUAGE DerivingStrategies #-}
4−{-# LANGUAGE LambdaCase #-}
51{-# language AllowAmbiguousTypes #-}
62{-# language ConstraintKinds #-}
73{-# language DataKinds #-}
4+{-# language DeriveAnyClass #-}
5+{-# language DeriveGeneric #-}
6+{-# language DerivingStrategies #-}
87{-# language FlexibleContexts #-}
98{-# language FlexibleInstances #-}
109{-# language GADTs #-}
11−{-# language InstanceSigs #-}
10+{-# language LambdaCase #-}
1211{-# language MultiParamTypeClasses #-}
13−{-# language NamedFieldPuns #-}
14−{-# language QuantifiedConstraints #-}
1512{-# language RankNTypes #-}
1613{-# language RecordWildCards #-}
1714{-# language ScopedTypeVariables #-}
1815{-# language StandaloneKindSignatures #-}
1916{-# language TypeApplications #-}
2017{-# language TypeFamilies #-}
21−{-# language TypeOperators #-}
2218{-# language UndecidableInstances #-}
2319
2420module Rel8.Schema.HTable.Vectorize
2521 ( HVectorize
2622 , hvectorize, hunvectorize
2723 , happend, hempty
28− , hrelabel
24+ , hproject
25+ , hcolumn
2926 )
3027where
3128
3229-- base
33−import Data.Kind ( Type )
30+import Data.Kind ( Constraint, Type )
3431import Data.List.NonEmpty ( NonEmpty )
35−import Data.Type.Equality ( (:~:)( Refl ) )
32+import GHC.Generics (Generic)
3633import Prelude
3734
3835-- rel8
39−import Rel8.Schema.Context.Label ( HLabelable, hlabeler, hunlabeler )
36+import Rel8.FCF ( Eval, Exp )
37+import Rel8.Schema.Dict ( Dict( Dict ) )
4038import qualified Rel8.Schema.Kind as K
41−import Rel8.Schema.HTable
42− ( HTable
43− , hfield, htabulate, htabulateA, hspecs
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 )
4445 )
45−import Rel8.Schema.Nullability ( IsMaybe, Nullability( NonNullable ) )
46−import Rel8.Schema.Spec ( 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(..) )
4749import Rel8.Type.Array ( listTypeInformation, nonEmptyTypeInformation )
4850import Rel8.Type.Information ( TypeInformation )
4951
5052-- semialign
51−import Data.Zip ( Unzip, Repeat, Zippy(..) )
52−import Rel8.FCF
53−import Rel8.Schema.HTable.MapTable
54−import GHC.Generics (Generic)
53+import Data.Zip ( Unzip, Zip, Zippy(..) )
5554
5655
56+type Vector :: (Type -> Type) -> Constraint
5757class Vector list where
58− listIsn'tMaybe :: proxy a -> IsMaybe (list a) :~: 'False
58+ listNotNull :: proxy a -> Dict NotNull (list a)
5959 vectorTypeInformation :: ()
60− => Nullability a ma
61− -> TypeInformation a
62− -> TypeInformation (list ma)
60+ => Nullity a
61+ -> TypeInformation (Unnullify a)
62+ -> TypeInformation (list a)
6363
6464
6565instance Vector [] where
66− listIsn'tMaybe _ = Refl
66+ listNotNull _ = Dict
6767 vectorTypeInformation = listTypeInformation
6868
6969
7070instance Vector NonEmpty where
71− listIsn'tMaybe _ = Refl
71+ listNotNull _ = Dict
7272 vectorTypeInformation = nonEmptyTypeInformation
7373
7474
@@ -78,84 +78,66 @@ newtype HVectorize list table context = HVectorize (HMapTable (Vectorize list) t
7878 deriving anyclass HTable
7979
8080
81−data Vectorize :: (Type -> Type) -> Spec -> Exp Spec
81+data Vectorize :: (Type -> Type) -> Type -> Exp Type
8282
8383
84−type instance Eval (Vectorize list ('Spec labels necessity _ a)) = 'Spec labels necessity (list a) (list a)
84+type instance Eval (Vectorize list a) = list a
8585
8686
8787instance Vector list => MapSpec (Vectorize list) where
8888 mapInfo = \case
89− SSpec {..} -> case listIsn'tMaybe @list nullability of
90− Refl -> SSpec
91− { nullability = NonNullable
92− , info = vectorTypeInformation nullability info
89+ Spec {..} -> case listNotNull @list nullity of
90+ Dict -> Spec
91+ { nullity = NotNull
92+ , info = vectorTypeInformation nullity info
9393 , ..
9494 }
9595
9696
9797hvectorize :: (HTable t, Unzip f, Vector list)
98− => (forall labels necessity db a. ()
99− => SSpec ('Spec labels necessity db a)
100− -> f (context ('Spec labels necessity db a))
101− -> context' ('Spec labels necessity (list a) (list a)))
98+ => (forall a. Spec a -> f (context a) -> context' (list a))
10299 -> f (t context)
103100 -> HVectorize list t context'
104101hvectorize vectorizer as = HVectorize $ htabulate $ \(HMapTableField field) ->
105102 case hfield hspecs field of
106− spec@SSpec {} -> vectorizer spec (fmap (`hfield` field) as)
103+ spec -> vectorizer spec (fmap (`hfield` field) as)
107104{-# INLINABLE hvectorize #-}
108105
109106
110−hunvectorize :: (HTable t, Repeat f, Vector list)
111− => (forall labels necessity db a. ()
112− => SSpec ('Spec labels necessity db a)
113− -> context ('Spec labels necessity (list a) (list a))
114− -> f (context' ('Spec labels necessity db a)))
107+hunvectorize :: (HTable t, Zip f, Vector list)
108+ => (forall a. Spec a -> context (list a) -> f (context' a))
115109 -> HVectorize list t context
116110 -> f (t context')
117111hunvectorize unvectorizer (HVectorize table) =
118112 getZippy $ htabulateA $ \field -> case hfield hspecs field of
119− spec@SSpec{} -> case hfield table (HMapTableField field) of
113+ spec -> case hfield table (HMapTableField field) of
120114 a -> Zippy (unvectorizer spec a)
121115{-# INLINABLE hunvectorize #-}
122116
123117
124−happend :: (HTable t, Vector list) =>
125− ( forall labels necessity db a. ()
126− => Nullability db a
127− -> TypeInformation db
128− -> context ('Spec labels necessity (list a) (list a))
129− -> context ('Spec labels necessity (list a) (list a))
130− -> context ('Spec labels necessity (list a) (list a))
131− )
118+happend :: (HTable t, Vector list)
119+ => (forall a. Spec a -> context (list a) -> context (list a) -> context (list a))
132120 -> HVectorize list t context
133121 -> HVectorize list t context
134122 -> HVectorize list t context
135123happend append (HVectorize as) (HVectorize bs) = HVectorize $
136124 htabulate $ \field@(HMapTableField j) -> case (hfield as field, hfield bs field) of
137125 (a, b) -> case hfield hspecs j of
138− SSpec {nullability, info} -> append nullability info a b
126+ spec -> append spec a b
139127
140128
141−hempty :: HTable t =>
142− ( forall labels necessity db a. ()
143− => Nullability db a
144− -> TypeInformation db
145− -> context ('Spec labels necessity [a] [a])
146− )
129+hempty :: HTable t
130+ => (forall a. Spec a -> context [a])
147131 -> HVectorize [] t context
148−hempty empty = HVectorize $ htabulate $ \(HMapTableField field) -> case hfield hspecs field of
149− SSpec {nullability, info} -> empty nullability info
132+hempty empty = HVectorize $ htabulate $ \(HMapTableField field) ->
133+ empty (hfield hspecs field)
150134
151135
152−instance HLabelable g => HLabelable (Precompose (Vectorize list) g) where
153− hlabeler = Precompose . hlabeler . precomposed
154− hunlabeler = Precompose . hunlabeler . precomposed
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)
155140
156141
157−hrelabel :: HLabelable context
158− => (forall ctx. HLabelable ctx => t ctx -> u ctx)
159− -> HVectorize list t context
160− -> HVectorize list u context
161−hrelabel f (HVectorize (HMapTable table)) = HVectorize (HMapTable (f table))
142+hcolumn :: HVectorize list (HIdentity a) context -> context (list a)
143+hcolumn (HVectorize (HMapTable (HIdentity (Precompose a)))) = a
src/Rel8/Schema/Insert.hsdeleted−160
@@ -1,160 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language DuplicateRecordFields #-}
3−{-# language FlexibleContexts #-}
4−{-# language FlexibleInstances #-}
5−{-# language GADTs #-}
6−{-# language LambdaCase #-}
7−{-# language MultiParamTypeClasses #-}
8−{-# language NamedFieldPuns #-}
9−{-# language ScopedTypeVariables #-}
10−{-# language StandaloneKindSignatures #-}
11−{-# language TypeApplications #-}
12−{-# language TypeFamilies #-}
13−{-# language UndecidableInstances #-}
14−{-# language UndecidableSuperClasses #-}
15−
16−module Rel8.Schema.Insert
17− ( Insert(..)
18− , OnConflict(..)
19− , Col( RequiredInsert, OptionalInsert )
20− , Insertion(..)
21− , Inserts
22− )
23−where
24−
25−-- base
26−import Data.Functor.Identity ( Identity )
27−import Data.Kind ( Constraint, Type )
28−import Prelude
29−
30−-- rel8
31−import Rel8.Aggregate ( Aggregate )
32−import Rel8.Expr ( Expr )
33−import Rel8.Kind.Necessity ( Necessity(Optional, Required) )
34−import Rel8.Opaque ( Opaque, Opaque1 )
35−import Rel8.Schema.Context ( Interpretation(..) )
36−import Rel8.Schema.Context.Label ( Labelable(..) )
37−import Rel8.Schema.Context.Nullify
38− ( Nullifiable, encodeTag, decodeTag, nullifier, unnullifier
39− , runTag, unnull
40− )
41−import Rel8.Schema.HTable.Type ( HType(HType) )
42−import qualified Rel8.Schema.Kind as K
43−import Rel8.Schema.Name ( Name, Selects )
44−import Rel8.Schema.Nullability ( Sql )
45−import Rel8.Schema.Spec ( SSpec(SSpec, nullability), Spec(Spec) )
46−import Rel8.Schema.Table ( TableSchema )
47−import Rel8.Statement.Returning ( Returning )
48−import Rel8.Table ( Table(..) )
49−import Rel8.Table.Recontextualize ( Recontextualize )
50−import Rel8.Type ( DBType )
51−
52−
53−-- | @OnConflict@ allows you to add an @ON CONFLICT@ clause to an @INSERT@
54−-- statement.
55−data OnConflict
56− = Abort -- ^ @ON CONFLICT ABORT@
57− | DoNothing -- ^ @ON CONFLICT DO NOTHING@
58−
59−
60−-- | The constituent parts of a SQL @INSERT@ statement.
61−type Insert :: K.Context
62−data Insert a where
63− Insert :: (Selects names exprs, Inserts exprs inserts) =>
64− { into :: TableSchema names
65− -- ^ Which table to insert into.
66− , rows :: [inserts]
67− -- ^ The rows to insert.
68− , onConflict :: OnConflict
69− -- ^ What to do if the inserted rows conflict with data already in the
70− -- table.
71− , returning :: Returning names a
72− -- ^ What information to return on completion.
73− }
74− -> Insert a
75−
76−
77−instance Interpretation Insert where
78− data Col Insert _spec where
79− RequiredInsert :: Expr a -> Col Insert ('Spec labels 'Required db a)
80− OptionalInsert :: Maybe (Expr a) -> Col Insert ('Spec labels 'Optional db a)
81−
82−
83−type Insertion :: K.Context
84−newtype Insertion a = Insertion (Expr a)
85−
86−
87−instance Sql DBType a => Table Insert (Insertion a) where
88− type Columns (Insertion a) = HType a
89− type Context (Insertion a) = Insert
90−
91− toColumns (Insertion a) = HType (RequiredInsert a)
92− fromColumns (HType (RequiredInsert a)) = Insertion a
93−
94−
95−instance Sql DBType a =>
96− Recontextualize Aggregate Insert (Aggregate (Expr a)) (Insertion a)
97−
98−
99−instance Sql DBType a => Recontextualize Expr Insert (Expr a) (Insertion a)
100−
101−
102−instance Sql DBType a =>
103− Recontextualize Identity Insert (Identity a) (Insertion a)
104−
105−
106−instance Sql DBType a =>
107− Recontextualize Insert Aggregate (Insertion a) (Aggregate (Expr a))
108−
109−
110−instance Sql DBType a => Recontextualize Insert Expr (Insertion a) (Expr a)
111−
112−
113−instance Sql DBType a =>
114− Recontextualize Insert Identity (Insertion a) (Identity a)
115−
116−
117−instance Sql DBType a => Recontextualize Insert Insert (Insertion a) (Insertion a)
118−
119−
120−instance Sql DBType a => Recontextualize Insert Name (Insertion a) (Name a)
121−
122−
123−instance Sql DBType a => Recontextualize Name Insert (Name a) (Insertion a)
124−
125−
126−instance Labelable Insert where
127− labeler = \case
128− RequiredInsert a -> RequiredInsert a
129− OptionalInsert ma -> OptionalInsert ma
130−
131− unlabeler = \case
132− RequiredInsert a -> RequiredInsert a
133− OptionalInsert ma -> OptionalInsert ma
134−
135−
136−instance Nullifiable Insert where
137− encodeTag = RequiredInsert
138− decodeTag (RequiredInsert a) = a
139−
140− nullifier tag SSpec {nullability} = \case
141− RequiredInsert a -> RequiredInsert $ runTag nullability tag a
142− OptionalInsert ma -> OptionalInsert $ runTag nullability tag <$> ma
143−
144− unnullifier _ SSpec {nullability} = \case
145− RequiredInsert a -> RequiredInsert $ unnull nullability a
146− OptionalInsert ma -> OptionalInsert $ unnull nullability <$> ma
147−
148− {-# INLINABLE encodeTag #-}
149− {-# INLINABLE decodeTag #-}
150− {-# INLINABLE nullifier #-}
151− {-# INLINABLE unnullifier #-}
152−
153−
154−
155−-- | @Inserts a b@ means that the columns in @a@ are compatible for inserting
156−-- with the table @b@.
157−type Inserts :: Type -> Type -> Constraint
158−class Recontextualize Expr Insert exprs inserts => Inserts exprs inserts
159−instance Recontextualize Expr Insert exprs inserts => Inserts exprs inserts
160−instance {-# OVERLAPPING #-} Inserts (Opaque1 Expr Opaque) (Opaque1 Insert Opaque)
src/Rel8/Schema/Kind.hs+8−14
@@ -1,8 +1,9 @@
11{-# language StandaloneKindSignatures #-}
22
33module Rel8.Schema.Kind
4− ( Context, Table
5− , HContext, HTable
4+ ( Rel8able
5+ , Context
6+ , HTable
67 )
78where
89
@@ -10,21 +11,14 @@ where
1011import Data.Kind ( Type )
1112import Prelude ()
1213
13−-- rel8
14−import Rel8.Schema.Spec ( Spec )
1514
16−
17−type HContext :: Type
18−type HContext = Spec -> Type
15+type Context :: Type
16+type Context = Type -> Type
1917
2018
2119type HTable :: Type
22−type HTable = HContext -> Type
23−
24−
25−type Context :: Type
26−type Context = Type -> Type
20+type HTable = Context -> Type
2721
2822
29−type Table :: Type
30−type Table = Context -> Type
23+type Rel8able :: Type
24+type Rel8able = Context -> Type
src/Rel8/Schema/Name.hs+32−67
@@ -2,45 +2,45 @@
22{-# language DerivingStrategies #-}
33{-# language FlexibleContexts #-}
44{-# language FlexibleInstances #-}
5+{-# language GADTs #-}
56{-# language GeneralizedNewtypeDeriving #-}
67{-# language MultiParamTypeClasses #-}
78{-# language RankNTypes #-}
8−{-# language ScopedTypeVariables #-}
99{-# language StandaloneKindSignatures #-}
10−{-# language TypeApplications #-}
1110{-# language TypeFamilies #-}
1211{-# language UndecidableInstances #-}
13−{-# language UndecidableSuperClasses #-}
1412
1513module Rel8.Schema.Name
1614 ( Name(..)
17− , Col( NameCol )
1815 , Selects
16+ , ppColumn
1917 )
2018where
2119
2220-- base
23−import Data.Functor.Identity ( Identity )
24−import qualified Data.List.NonEmpty as NonEmpty
21+import Data.Functor.Identity ( Identity( Identity ) )
2522import Data.Kind ( Constraint, Type )
2623import Data.String ( IsString )
2724import Prelude
2825
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+
2933-- rel8
3034import Rel8.Expr ( Expr )
31−import Rel8.Kind.Labels ( KnownLabels, labelsSing, renderLabels )
32−import Rel8.Opaque ( Opaque, Opaque1 )
33−import Rel8.Schema.Context ( Interpretation, Col )
34−import Rel8.Schema.Context.Label ( Labelable, labeler, unlabeler )
35−import Rel8.Schema.Context.Nullify
36− ( Nullifiable, encodeTag, decodeTag, nullifier, unnullifier
37− )
38−import Rel8.Schema.HTable.Type ( HType( HType ) )
3935import qualified Rel8.Schema.Kind as K
40−import Rel8.Schema.Nullability ( Sql )
41−import Rel8.Schema.Spec ( Spec( Spec ) )
42−import Rel8.Table ( Table, Columns, Context, fromColumns, toColumns )
43−import Rel8.Table.Recontextualize ( Recontextualize )
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 )
4444import Rel8.Type ( DBType )
4545
4646
@@ -51,62 +51,27 @@ import Rel8.Type ( DBType )
5151type Name :: K.Context
5252newtype Name a = Name String
5353 deriving stock Show
54− deriving newtype (IsString, Monoid, Semigroup)
54+ deriving newtype IsString
5555
5656
5757instance Sql DBType a => Table Name (Name a) where
58− type Columns (Name a) = HType a
58+ type Columns (Name a) = HIdentity a
5959 type Context (Name a) = Name
60+ type FromExprs (Name a) = a
61+ type Transpose to (Name a) = to a
6062
61− toColumns (Name a) = HType (NameCol a)
62− fromColumns (HType (NameCol a)) = Name a
63−
64−
65−instance Sql DBType a => Recontextualize Expr Name (Expr a) (Name a)
66−
67−
68−instance Sql DBType a => Recontextualize Identity Name (Identity a) (Name a)
69−
70−
71−instance Sql DBType a => Recontextualize Name Expr (Name a) (Expr a)
72−
73−
74−instance Sql DBType a => Recontextualize Name Identity (Name a) (Identity a)
75−
76−
77−instance Sql DBType a => Recontextualize Name Name (Name a) (Name a)
78−
79−
80−instance Interpretation Name where
81− newtype Col Name _spec = NameCol String
82−
83−
84−instance Labelable Name where
85− labeler (NameCol a) = NameCol a
86− unlabeler (NameCol a) = NameCol a
87−
88−
89−instance Nullifiable Name where
90− encodeTag _ = nameFromLabel
91− decodeTag _ = mempty
92− nullifier _ _ (NameCol name) = NameCol name
93− unnullifier _ _ (NameCol name) = NameCol name
94−
95− {-# INLINABLE encodeTag #-}
96− {-# INLINABLE decodeTag #-}
97− {-# INLINABLE nullifier #-}
98− {-# INLINABLE unnullifier #-}
99−
100−
101−nameFromLabel :: forall labels necessity db a.
102− KnownLabels labels => Col Name ('Spec labels necessity db a)
103−nameFromLabel = case labelsSing @labels of
104− labels -> NameCol (NonEmpty.last (renderLabels labels))
63+ toColumns a = HIdentity a
64+ fromColumns (HIdentity a) = a
65+ toResult a = HIdentity (Identity a)
66+ fromResult (HIdentity (Identity a)) = a
10567
10668
10769-- | @Selects a b@ means that @a@ is a schema (i.e., a 'Table' of 'Name's) for
10870-- the 'Expr' columns in @b@.
10971type Selects :: Type -> Type -> Constraint
110−class Recontextualize Name Expr names exprs => Selects names exprs
111−instance Recontextualize Name Expr names exprs => Selects names exprs
112−instance {-# OVERLAPPING #-} Selects (Opaque1 Name Opaque) (Opaque1 Expr Opaque)
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−106
@@ -1,106 +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−{-# language UndecidableSuperClasses #-}
13−
14−module Rel8.Schema.Nullability
15− ( IsMaybe, Nullify, Unnullify
16− , Nullability( Nullable, NonNullable )
17− , Sql
18− , Nullabilizes, nullabilization
19− )
20−where
21−
22−-- base
23−import Data.Kind ( Constraint, Type )
24−import Prelude
25−
26−-- rel8
27−import Rel8.Opaque ( Opaque )
28−
29−
30−type IsMaybe :: Type -> Bool
31−type family IsMaybe a where
32− IsMaybe (Maybe _) = 'True
33− IsMaybe _ = 'False
34−
35−
36−type Unnullify' :: Bool -> Type -> Type
37−type family Unnullify' isMaybe ma where
38− Unnullify' 'False a = a
39− Unnullify' 'True (Maybe a) = a
40−
41−
42−type Unnullify :: Type -> Type
43−type Unnullify a = Unnullify' (IsMaybe a) a
44−
45−
46−type Nullify' :: Bool -> Type -> Type
47−type family Nullify' isMaybe a where
48− Nullify' 'False a = a
49− Nullify' 'True a = Maybe a
50−
51−
52−type Nullify :: Type -> Type
53−type Nullify a = Maybe (Unnullify a)
54−
55−
56−type Nullability :: Type -> Type -> Type
57−data Nullability a ma where
58− NonNullable :: IsMaybe a ~ 'False => Nullability a a
59− Nullable :: IsMaybe a ~ 'False => Nullability a (Maybe a)
60−
61−
62−type Nullabilizes' :: Bool -> Type -> Type -> Constraint
63−class
64− ( IsMaybe ma ~ isMaybe
65− , IsMaybe a ~ 'False
66− , Unnullify ma ~ a
67− , Nullify' isMaybe a ~ ma
68− ) => Nullabilizes' isMaybe a ma | isMaybe ma -> a, isMaybe a -> ma
69− where
70− nullabilization' :: Nullability a ma
71−
72−
73−instance IsMaybe a ~ 'False => Nullabilizes' 'False a a where
74− nullabilization' = NonNullable
75−
76−
77−instance IsMaybe a ~ 'False => Nullabilizes' 'True a (Maybe a) where
78− nullabilization' = Nullable
79−
80−
81−type Nullabilizes :: Type -> Type -> Constraint
82−class Nullabilizes' (IsMaybe ma) a ma => Nullabilizes a ma
83−instance Nullabilizes' (IsMaybe ma) a ma => Nullabilizes a ma
84−instance {-# OVERLAPPING #-} Nullabilizes Opaque Opaque
85−
86−
87−-- | The @Sql@ type class describes both null and not null database values,
88−-- constrained by a specific class.
89−--
90−-- For example, if you see @Sql DBEq a@, this means any database type that
91−-- supports equality, and @a@ can either be exactly an @a@, or it could also be
92−-- @Maybe a@.
93−type Sql :: (Type -> Constraint) -> Type -> Constraint
94−class
95− ( (forall c. (forall x. (constraint x => c x)) => Sql c a)
96− , Nullabilizes (Unnullify a) a
97− , constraint (Unnullify a)
98− )
99− => Sql constraint a
100−instance (constraint db, Nullabilizes db a) => Sql constraint a
101−instance {-# OVERLAPPING #-} (constraint Opaque, Sql constraint Opaque) => Sql constraint Opaque
102−-- instance {-# OVERLAPPING #-} Sql OpaqueC Opaque => Sql OpaqueC Opaque
103−
104−
105−nullabilization :: forall a db. Nullabilizes db a => Nullability db a
106−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+18−61
@@ -1,77 +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− , KContext, HKTable
12− , KTable
6+ ( Spec( Spec, labels, info, nullity )
7+ , specification
138 )
149where
1510
1611-- base
17−import Data.Kind ( Constraint, Type )
18−import Prelude ()
12+import Data.Kind ( Type )
13+import Prelude
1914
2015-- rel8
21−import Rel8.Kind.Labels ( Labels, SLabels, KnownLabels, labelsSing )
22−import Rel8.Kind.Necessity
23− ( Necessity
24− , SNecessity
25− , KnownNecessity, necessitySing
26− )
27−import Rel8.Schema.Nullability ( Unnullify, Nullability, Sql, nullabilization )
16+import Rel8.Schema.Null ( Nullity, Sql, Unnullify, nullable )
2817import Rel8.Type ( DBType, typeInformation )
2918import Rel8.Type.Information ( TypeInformation )
3019
3120
32−type Spec :: Type
33−data Spec = Spec Labels Necessity Type Type
34−
35−
36−type SSpec :: Spec -> Type
37−data SSpec spec where
38− SSpec ::
39− { labels :: SLabels labels
40− , necessity :: SNecessity necessity
41− , info :: TypeInformation db
42− , nullability :: Nullability db a
43− }
44− -> SSpec ('Spec labels necessity db a)
45−
46−
47−type KnownSpec :: Spec -> Constraint
48−class KnownSpec spec where
49− specSing :: SSpec spec
50−
51−
52−instance
53− ( KnownLabels labels
54− , KnownNecessity necessity
55− , Sql DBType a
56− , db ~ Unnullify a
57− )
58− => KnownSpec ('Spec labels necessity db a)
59− where
60− specSing = SSpec
61− { labels = labelsSing
62− , necessity = necessitySing
63− , info = typeInformation
64− , nullability = nullabilization
65− }
66−
67−
68−type KContext :: Type
69−type KContext = Spec -> Type
70−
71−
72−type HKTable :: Type
73−type HKTable = KContext -> Type
21+type Spec :: Type -> Type
22+data Spec a = Spec
23+ { labels :: [String]
24+ , info :: TypeInformation (Unnullify a)
25+ , nullity :: Nullity a
26+ }
7427
7528
76−type KTable :: Type
77−type KTable = (Type -> Type) -> Type
29+specification :: Sql DBType a => Spec a
30+specification = Spec
31+ { labels = []
32+ , info = typeInformation
33+ , nullity = nullable
34+ }
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−54
@@ -1,54 +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 qualified Rel8.Schema.Kind as K
21−import Rel8.Schema.Spec ( Spec )
22−
23−
24−type Structure :: K.Context
25−data Structure a
26−
27−
28−type Shape :: Type
29−data Shape
30− = Column Spec
31− | Either Type Type
32− | List Type
33− | Maybe Type
34− | NonEmpty Type
35− | These Type Type
36−
37−
38−type Shape1 :: (a -> Shape) -> a -> Type
39−data Shape1 shape a
40−
41−
42−type Shape2 :: (a -> b -> Shape) -> a -> b -> Type
43−data Shape2 shape a b
44−
45−
46−type IsStructure :: Type -> Bool
47−type family IsStructure a where
48− IsStructure (Shape1 _ _) = 'True
49− IsStructure (Shape2 _ _ _) = 'True
50− IsStructure (_, _) = 'True
51− IsStructure (_, _, _) = 'True
52− IsStructure (_, _, _, _) = 'True
53− IsStructure (_, _, _, _, _) = 'True
54− IsStructure _ = 'False
src/Rel8/Schema/Table.hs+21−14
@@ -1,34 +1,34 @@
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
20+
21+-- pretty
22+import Text.PrettyPrint ( Doc )
23+
1224
1325-- | The schema for a table. This is used to specify the name and schema that a
1426-- table belongs to (the @FROM@ part of a SQL query), along with the schema of
1527-- the columns within this table.
1628--
1729-- For each selectable table in your database, you should provide a
18−-- @TableSchema@ in order to interact with the table via Rel8. For a table
19−-- storing a list of projects (as defined in the introduction):
20−--
21−-- >>> :{
22−-- projectSchema :: TableSchema (Project ColumnSchema)
23−-- projectSchema = TableSchema
24−-- { tableName = "project"
25−-- , tableSchema = Nothing -- Assumes that the 'project' table is reachable from your connection's search_path
26−-- , tableColumns = Project
27−-- { projectAuthorId = "author_id"
28−-- , projectName = "name"
29−-- }
30−-- }
31−-- :}
30+-- @TableSchema@ in order to interact with the table via Rel8.
31+type TableSchema :: Type -> Type
3232data TableSchema names = TableSchema
3333 { name :: String
3434 -- ^ The name of the table.
@@ -40,3 +40,10 @@ data TableSchema names = TableSchema
4040 -- data type here, parameterized by the 'Rel8.ColumnSchema.ColumnSchema' functor.
4141 }
4242 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+35−66
@@ -1,40 +1,37 @@
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 )
1617import Data.Kind ( Type )
1718import Prelude
1819
1920-- hasql
20−import Hasql.Connection ( Connection )
21−import qualified Hasql.Decoders as Hasql
2221import qualified Hasql.Encoders as Hasql
23−import qualified Hasql.Session as Hasql
2422import qualified Hasql.Statement as Hasql
2523
26−-- opaleye
27−import qualified Opaleye.Internal.Manipulation as Opaleye
24+-- pretty
25+import Text.PrettyPrint ( Doc, (<+>), ($$), text )
2826
2927-- rel8
3028import Rel8.Expr ( Expr )
31−import Rel8.Expr.Opaleye ( toColumn, toPrimExpr )
29+import Rel8.Query ( Query )
3230import Rel8.Schema.Name ( Selects )
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.Serialize ( Serializable, parse )
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 )
3835
3936-- text
4037import qualified Data.Text as Text
@@ -47,7 +44,10 @@ data Delete a where
4744 Delete :: Selects names exprs =>
4845 { from :: TableSchema names
4946 -- ^ Which table to delete from.
50− , deleteWhere :: exprs -> Expr Bool
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
5151 -- ^ Which rows should be selected for deletion.
5252 , returning :: Returning names a
5353 -- ^ What to return from the @DELETE@ statement.
@@ -55,56 +55,25 @@ data Delete a where
5555 -> Delete a
5656
5757
58−-- | Run a @DELETE@ statement.
59−--
60−-- >>> mapM_ print =<< select c (each projectSchema)
61−-- Project {projectAuthorId = 1, projectName = "rel8"}
62−-- Project {projectAuthorId = 2, projectName = "aeson"}
63−-- Project {projectAuthorId = 2, projectName = "text"}
64−--
65−-- >>> :{
66−-- delete c Delete
67−-- { from = projectSchema
68−-- , deleteWhere = \p -> projectName p ==. lit "rel8"
69−-- , returning = Projection projectName
70−-- }
71−-- :}
72−-- ["rel8"]
73−--
74−-- >>> mapM_ print =<< select c (each projectSchema)
75−-- Project {projectAuthorId = 2, projectName = "aeson"}
76−-- Project {projectAuthorId = 2, projectName = "text"}
77−delete :: Connection -> Delete a -> IO a
78−delete c Delete {from, deleteWhere, returning} =
79− case returning of
80− NumberOfRowsAffected -> Hasql.run session c >>= either throwIO pure
81− where
82− session = Hasql.statement () statement
83− statement = Hasql.Statement bytes params decode prepare
84− bytes = encodeUtf8 $ Text.pack sql
85− params = Hasql.noParams
86− decode = Hasql.rowsAffected
87− prepare = False
88− sql = Opaleye.arrangeDeleteSql from' where'
89− where
90− from' = table $ toColumns <$> from
91− 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
9268
93− Projection project -> Hasql.run session c >>= either throwIO pure
94− where
95− session = Hasql.statement () statement
96− statement = Hasql.Statement bytes params decode prepare
97− bytes = encodeUtf8 $ Text.pack sql
98− params = Hasql.noParams
99− decode = decoder project
100− prepare = False
101− sql =
102− Opaleye.arrangeDeleteReturningSql unpackspec from' where' project'
103− where
104− from' = table $ toColumns <$> from
105− where' = toColumn . toPrimExpr . deleteWhere . fromColumns
106− 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
10773 where
108− decoder :: forall exprs projection a. Serializable projection a
109− => (exprs -> projection) -> Hasql.Result [a]
110− 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+60−70
@@ -1,99 +1,89 @@
1+{-# language DuplicateRecordFields #-}
2+{-# language FlexibleContexts #-}
13{-# language GADTs #-}
24{-# language NamedFieldPuns #-}
3−{-# language ScopedTypeVariables #-}
4−{-# language TypeApplications #-}
5+{-# language RecordWildCards #-}
6+{-# language StandaloneKindSignatures #-}
7+{-# language StrictData #-}
58
69module Rel8.Statement.Insert
710 ( Insert(..)
8− , OnConflict(..)
911 , insert
12+ , ppInsert
13+ , ppInto
1014 )
1115where
1216
1317-- base
14−import Control.Exception ( throwIO )
15−import Data.List.NonEmpty ( NonEmpty( (:|) ) )
18+import Data.Foldable ( toList )
19+import Data.Kind ( Type )
1620import Prelude
1721
1822-- hasql
19−import Hasql.Connection ( Connection )
20−import qualified Hasql.Decoders as Hasql
2123import qualified Hasql.Encoders as Hasql
22−import qualified Hasql.Session as Hasql
2324import qualified Hasql.Statement as Hasql
2425
2526-- opaleye
26−import qualified Opaleye.Internal.Manipulation as Opaleye
27−import qualified Opaleye.Manipulation as Opaleye
27+import qualified Opaleye.Internal.HaskellDB.Sql.Print as Opaleye
28+
29+-- pretty
30+import Text.PrettyPrint ( Doc, (<+>), ($$), parens, text )
2831
2932-- rel8
30−import Rel8.Schema.Insert ( Insert(..), OnConflict(..) )
31−import Rel8.Statement.Returning ( Returning( Projection, NumberOfRowsAffected ) )
32−import Rel8.Table ( fromColumns, toColumns )
33−import Rel8.Table.Opaleye ( table, unpackspec )
34−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 )
3541
3642-- text
3743import qualified Data.Text as Text ( pack )
3844import Data.Text.Encoding ( encodeUtf8 )
3945
4046
41−-- | Run an @INSERT@ statement
42−--
43−-- >>> :{
44−-- insert c Insert
45−-- { into = authorSchema
46−-- , rows = [ lit Author{ authorName = "Gabriel Gonzales", authorId = AuthorId 4, authorUrl = Just "https://haskellforall.com" } ]
47−-- , onConflict = Abort
48−-- , returning = NumberOfRowsAffected
49−-- }
50−-- :}
51−-- 1
52−insert :: Connection -> Insert a -> IO a
53−insert c Insert {into, rows, onConflict, returning} =
54− case (rows, returning) of
55− ([], NumberOfRowsAffected) -> pure 0
56− ([], Projection _) -> pure []
47+-- | The constituent parts of a SQL @INSERT@ statement.
48+type Insert :: Type -> Type
49+data Insert a where
50+ Insert :: Selects names exprs =>
51+ { into :: TableSchema names
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.
59+ , returning :: Returning names a
60+ -- ^ What information to return on completion.
61+ }
62+ -> Insert a
5763
58− (x:xs, NumberOfRowsAffected) -> Hasql.run session c >>= 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.arrangeInsertManySql into' rows' onConflict'
67− where
68− into' = table $ toColumns <$> into
69− rows' = toColumns <$> x :| xs
7064
71− (x:xs, Projection project) -> Hasql.run session c >>= 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.arrangeInsertManyReturningSql
81− unpackspec
82− into'
83− rows'
84− project'
85− onConflict'
86− where
87− into' = table $ toColumns <$> into
88− rows' = toColumns <$> x :| xs
89− project' = toColumns . project . fromColumns
65+ppInsert :: Insert a -> Doc
66+ppInsert Insert {..} =
67+ text "INSERT INTO" <+>
68+ ppInto into $$
69+ ppRows rows $$
70+ ppOnConflict into onConflict $$
71+ ppReturning into returning
9072
91− where
92− onConflict' =
93− case onConflict of
94− DoNothing -> Just Opaleye.DoNothing
95− Abort -> Nothing
9673
97− decoder :: forall exprs projection a. Serializable projection a
98− => (exprs -> projection) -> Hasql.Result [a]
99− decoder _ = Hasql.rowList (parse @projection @a)
74+ppInto :: Table Name a => TableSchema a -> Doc
75+ppInto table@TableSchema {columns} =
76+ ppTable table <+>
77+ parens (Opaleye.commaV ppColumn (toList (showNames columns)))
78+
79+
80+-- | Run an 'Insert' statement.
81+insert :: Insert a -> Hasql.Statement () a
82+insert i@Insert {returning} = Hasql.Statement bytes params decode prepare
83+ where
84+ bytes = encodeUtf8 $ Text.pack sql
85+ params = Hasql.noParams
86+ decode = decodeReturning returning
87+ prepare = False
88+ sql = show doc
89+ doc = ppInsert i
src/Rel8/Statement/OnConflict.hsnew file+106
@@ -0,0 +1,106 @@
1+{-# language DuplicateRecordFields #-}
2+{-# language FlexibleContexts #-}
3+{-# language GADTs #-}
4+{-# language LambdaCase #-}
5+{-# language NamedFieldPuns #-}
6+{-# language RecordWildCards #-}
7+{-# language StandaloneKindSignatures #-}
8+{-# language StrictData #-}
9+
10+module Rel8.Statement.OnConflict
11+ ( OnConflict(..)
12+ , Upsert(..)
13+ , ppOnConflict
14+ )
15+where
16+
17+-- base
18+import Data.Foldable ( toList )
19+import Data.Kind ( Type )
20+import Prelude
21+
22+-- opaleye
23+import qualified Opaleye.Internal.HaskellDB.Sql.Print as Opaleye
24+
25+-- pretty
26+import Text.PrettyPrint ( Doc, (<+>), ($$), 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+114−10
@@ -1,29 +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
1537import Rel8.Schema.Name ( Selects )
16−import Rel8.Table.Serialize ( Serializable )
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
19−-- | @INSERT@, @UPDATE@ and @DELETE@ all support returning either the number of
20−-- rows affected, or the actual rows modified. 'Projection' allows you to
21−-- project out of these returned rows, which can be useful if you want to log
22−-- exactly which rows were deleted, or to view a generated id (for example, if
23−-- using a column with an autoincrementing counter as a default value).
45+
46+-- | 'Rel8.Insert', 'Rel8.Update' and 'Rel8.Delete' all support returning either
47+-- the number of rows affected, or the actual rows modified.
2448type Returning :: Type -> Type -> Type
2549data 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.
2654 NumberOfRowsAffected :: Returning names Int64
27− Projection :: (Selects names exprs, Serializable projection a)
28− => (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)
2962 -> 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+121−35
@@ -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 Prelude
20+import Data.Foldable ( toList )
21+import Data.Kind ( Type )
22+import Data.Void ( Void )
23+import Prelude hiding ( undefined )
1324
1425-- hasql
15−import Hasql.Connection ( Connection )
1626import qualified Hasql.Decoders as Hasql
1727import qualified Hasql.Encoders as Hasql
18−import qualified Hasql.Session as Hasql
1928import qualified Hasql.Statement as Hasql
2029
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+
2144-- rel8
45+import Rel8.Expr ( Expr )
46+import Rel8.Expr.Bool ( false )
47+import Rel8.Expr.Opaleye ( toPrimExpr )
2248import Rel8.Query ( Query )
23−import Rel8.Query.SQL ( sqlForQuery, sqlForQueryWithNames )
49+import Rel8.Query.Opaleye ( toOpaleye )
2450import 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
2556import Rel8.Table.Serialize ( Serializable, parse )
57+import Rel8.Table.Undefined ( undefined )
2658
2759-- text
2860import qualified Data.Text as Text
2961import Data.Text.Encoding ( encodeUtf8 )
3062
3163
32−-- | Run a @SELECT@ query, returning all rows.
64+-- | Run a @SELECT@ statement, returning all rows.
3365select :: forall exprs a. Serializable exprs a
34− => Connection -> Query exprs -> IO [a]
35−select c query = case sqlForQuery query of
36− Nothing -> pure []
37− Just sql -> Hasql.run session c >>= 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− => Connection -> names -> Query exprs -> IO [a]
52−selectWithNames c names query = case sqlForQueryWithNames names query of
53− Nothing -> pure []
54− Just sql -> Hasql.run session c >>= 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+38−80
@@ -1,43 +1,37 @@
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 )
1516import Data.Kind ( Type )
1617import Prelude
1718
1819-- hasql
19−import Hasql.Connection ( Connection )
20−import qualified Hasql.Decoders as Hasql
2120import qualified Hasql.Encoders as Hasql
22−import qualified Hasql.Session as Hasql
2321import qualified Hasql.Statement as Hasql
2422
25−-- opaleye
26−import qualified Opaleye.Internal.Manipulation as Opaleye
27−
28−-- profunctors
29−import Data.Profunctor ( lmap )
23+-- pretty
24+import Text.PrettyPrint ( Doc, (<+>), ($$), text )
3025
3126-- rel8
3227import Rel8.Expr ( Expr )
33−import Rel8.Expr.Opaleye ( toColumn, toPrimExpr )
28+import Rel8.Query ( Query )
3429import Rel8.Schema.Name ( Selects )
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.Serialize ( Serializable, parse )
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 )
4135
4236-- text
4337import qualified Data.Text as Text
@@ -50,9 +44,12 @@ data Update a where
5044 Update :: Selects names exprs =>
5145 { target :: TableSchema names
5246 -- ^ Which table to update.
53− , set :: exprs -> exprs
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
5451 -- ^ How to update each selected row.
55− , updateWhere :: exprs -> Expr Bool
52+ , updateWhere :: from -> exprs -> Expr Bool
5653 -- ^ Which rows to select for update.
5754 , returning :: Returning names a
5855 -- ^ What to return from the @UPDATE@ statement.
@@ -60,66 +57,27 @@ data Update a where
6057 -> Update a
6158
6259
63−-- | Run an @UPDATE@ statement.
64−--
65−-- >>> mapM_ print =<< select c (each projectSchema)
66−-- Project {projectAuthorId = 1, projectName = "rel8"}
67−-- Project {projectAuthorId = 2, projectName = "aeson"}
68−-- Project {projectAuthorId = 2, projectName = "text"}
69−--
70−-- >>> :{
71−-- update c Update
72−-- { target = projectSchema
73−-- , set = \p -> p { projectName = "Rel8!" }
74−-- , updateWhere = \p -> projectName p ==. lit "rel8"
75−-- , returning = NumberOfRowsAffected
76−-- }
77−-- :}
78−-- 1
79−--
80−-- >>> mapM_ print =<< select c (each projectSchema)
81−-- Project {projectAuthorId = 2, projectName = "aeson"}
82−-- Project {projectAuthorId = 2, projectName = "text"}
83−-- Project {projectAuthorId = 1, projectName = "Rel8!"}
84−update :: Connection -> Update a -> IO a
85−update c Update {target, set, updateWhere, returning} =
86− case returning of
87− NumberOfRowsAffected -> Hasql.run session c >>= either throwIO pure
88− where
89− session = Hasql.statement () statement
90− statement = Hasql.Statement bytes params decode prepare
91− bytes = encodeUtf8 $ Text.pack sql
92− params = Hasql.noParams
93− decode = Hasql.rowsAffected
94− prepare = False
95− sql = Opaleye.arrangeUpdateSql target' set' where'
96− where
97− target' = lmap toInsert $ table $ toColumns <$> target
98− set' = toColumns . set . fromColumns
99− 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
10072
101− Projection project -> Hasql.run session c >>= either throwIO pure
102− where
103− session = Hasql.statement () statement
104− statement = Hasql.Statement bytes params decode prepare
105− bytes = encodeUtf8 $ Text.pack sql
106− params = Hasql.noParams
107− decode = decoder project
108− prepare = False
109− sql =
110− Opaleye.arrangeUpdateReturningSql
111− unpackspec
112− target'
113− set'
114− where'
115− project'
116− where
117− target' = lmap toInsert $ table $ toColumns <$> target
118− set' = toColumns . set . fromColumns
119− where' = toColumn . toPrimExpr . updateWhere . fromColumns
120− project' = toColumns . project . fromColumns
12173
74+-- | Run an @UPDATE@ statement.
75+update :: Update a -> Hasql.Statement () a
76+update u@Update {returning} = Hasql.Statement bytes params decode prepare
12277 where
123− decoder :: forall exprs projection a. Serializable projection a
124− => (exprs -> projection) -> Hasql.Result [a]
125− 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+47−28
@@ -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 )
2520import Rel8.Schema.Name ( Selects )
26−import Rel8.Schema.Table ( TableSchema( TableSchema ) )
27−import Rel8.Table.Alternative ( emptyTable )
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+149−147
@@ -1,40 +1,46 @@
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 {-# SOURCE #-} Rel8.Expr ( Expr )
24−import Rel8.Opaque ( Opaque, Opaque1 )
25−import Rel8.Schema.Context ( Col(..) )
26−import Rel8.Schema.Context.Label ( Labelable, labeler, unlabeler )
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
37+ )
38+import Rel8.Generic.Record ( Record(..) )
2739import Rel8.Schema.HTable ( HTable )
28−import Rel8.Schema.HTable.Identity ( HIdentity(..) )
29−import Rel8.Schema.HTable.Label ( HLabel, hlabel, hunlabel )
30−import Rel8.Schema.HTable.Pair ( HPair(..) )
31−import Rel8.Schema.HTable.Quartet ( HQuartet(..) )
32−import Rel8.Schema.HTable.Quintet ( HQuintet(..) )
33−import Rel8.Schema.HTable.Trio ( HTrio(..) )
34−import Rel8.Schema.HTable.Type ( HType( HType ) )
40+import Rel8.Schema.HTable.Identity ( HIdentity( HIdentity ) )
3541import qualified Rel8.Schema.Kind as K
36−import Rel8.Schema.Nullability ( Sql )
37−import Rel8.Schema.Spec ( KnownSpec )
42+import Rel8.Schema.Null ( Sql )
43+import Rel8.Schema.Result ( Result )
3844import Rel8.Type ( DBType )
3945
4046
@@ -42,177 +48,173 @@ import Rel8.Type ( DBType )
4248-- types that have a finite number of columns. Each of these columns contains
4349-- data under a shared context, and contexts describe how to interpret the
4450-- metadata about a column to a particular Haskell type. In Rel8, we have
45−-- contexts for expressions (the 'Expr' context), aggregations (the 'Aggregate'
46−-- context), insert values (the 'Insert' contex), among others.
51+-- contexts for expressions (the 'Rel8.Expr' context), aggregations (the
52+-- 'Rel8.Aggregate' context), insert values (the 'Rel8.Insert' contex), among
53+-- others.
4754--
4855-- In typical usage of Rel8 you don't need to derive instances of 'Table'
49−-- yourself, as anything that's an instance of 'Rel8able' is always a 'Table'.
56+-- yourself, as anything that's an instance of 'Rel8.Rel8able' is always a
57+-- 'Table'.
5058type Table :: K.Context -> Type -> Constraint
51−class (HTable (Columns a), context ~ Context a) => Table context a | a -> context where
59+class
60+ ( HTable (Columns a)
61+ , context ~ Context a
62+ , a ~ Transpose context a
63+ )
64+ => Table context a | a -> context
65+ where
5266 -- | The 'HTable' functor that describes the schema of this table.
5367 type Columns a :: K.HTable
5468
5569 -- | The common context that all columns use as an interpretation.
5670 type Context a :: K.Context
5771
58− toColumns :: a -> Columns a (Col (Context a))
59− fromColumns :: Columns a (Col (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
6075
76+ type Transpose (context' :: K.Context) a :: Type
6177
62−-- | Any 'HTable' is also a 'Table'.
63−instance HTable t => Table context (t (Col context)) where
64− type Columns (t (Col context)) = t
65− type Context (t (Col context)) = context
6678
67− toColumns = id
68− fromColumns = id
79+ toColumns :: a -> Columns a context
80+ fromColumns :: Columns a context -> a
6981
82+ fromResult :: Columns a Result -> FromExprs a
83+ toResult :: FromExprs a -> Columns a Result
7084
71−-- | Any context is trivially a table.
72−instance KnownSpec spec => Table context (Col context spec) where
73− type Columns (Col context spec) = HIdentity spec
74− type Context (Col 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
75150
76151 toColumns = HIdentity
77− fromColumns = unHIdentity
152+ fromColumns (HIdentity a) = a
153+ toResult a = HIdentity (Identity a)
154+ fromResult (HIdentity (Identity a)) = a
78155
79156
80−instance Sql DBType a => Table Identity (Identity a) where
81− type Columns (Identity a) = HType a
82− type Context (Identity a) = Identity
157+data TTable :: K.Context -> Type -> Exp Constraint
158+type instance Eval (TTable context a) = Table context a
83159
84− toColumns (Identity a) = HType (Result a)
85− fromColumns (HType (Result a)) = Identity a
86160
161+data TColumns :: Type -> Exp K.HTable
162+type instance Eval (TColumns a) = Columns a
87163
88−{-}
89−instance Sql DBType a => Table Insertion (Insertion a) where
90− type Columns (Insertion a) = HType a
91− type Context (Insertion a) = Insertion
92164
93− toColumns (Insertion a) = HType (RequiredInsert a)
94− fromColumns (HType (RequiredInsert a)) = Insertion a
95−-}
165+data TContext :: Type -> Exp K.Context
166+type instance Eval (TContext a) = Context a
96167
97168
98−instance
99− ( Table context a, Table context b
100− , Labelable context
101− ) =>
102− Table context (a, b)
103− where
104− type Columns (a, b) =
105− HPair
106− (HLabel "fst" (Columns a))
107− (HLabel "snd" (Columns b))
108− type Context (a, b) = Context a
109−
110− toColumns (a, b) = HPair
111− { hfst = hlabel labeler $ toColumns a
112− , hsnd = hlabel labeler $ toColumns b
113− }
114− fromColumns (HPair a b) =
115− ( fromColumns $ hunlabel unlabeler a
116− , fromColumns $ hunlabel unlabeler b
117− )
169+data TFromExprs :: Type -> Exp Type
170+type instance Eval (TFromExprs a) = FromExprs a
171+
172+
173+data TTranspose :: K.Context -> Type -> Exp Type
174+type instance Eval (TTranspose context a) = Transpose context a
175+
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)
118185
119186
120187instance
121188 ( Table context a, Table context b, Table context c
122− , Labelable context
123− ) => Table context (a, b, c)
124− where
125− type Columns (a, b, c) =
126− HTrio
127− (HLabel "fst" (Columns a))
128− (HLabel "snd" (Columns b))
129− (HLabel "trd" (Columns c))
130− type Context (a, b, c) = Context a
131−
132− toColumns (a, b, c) = HTrio
133− { hfst = hlabel labeler $ toColumns a
134− , hsnd = hlabel labeler $ toColumns b
135− , htrd = hlabel labeler $ toColumns c
136− }
137− fromColumns (HTrio a b c) =
138− ( fromColumns $ hunlabel unlabeler a
139− , fromColumns $ hunlabel unlabeler b
140− , fromColumns $ hunlabel unlabeler c
141− )
189+ )
190+ => Table context (a, b, c)
142191
143192
144193instance
145194 ( Table context a, Table context b, Table context c, Table context d
146− , Labelable context
147− ) => Table context (a, b, c, d)
148− where
149− type Columns (a, b, c, d) =
150− HQuartet
151− (HLabel "fst" (Columns a))
152− (HLabel "snd" (Columns b))
153− (HLabel "trd" (Columns c))
154− (HLabel "frt" (Columns d))
155− type Context (a, b, c, d) = Context a
156−
157− toColumns (a, b, c, d) = HQuartet
158− { hfst = hlabel labeler $ toColumns a
159− , hsnd = hlabel labeler $ toColumns b
160− , htrd = hlabel labeler $ toColumns c
161− , hfrt = hlabel labeler $ toColumns d
162− }
163− fromColumns (HQuartet a b c d) =
164− ( fromColumns $ hunlabel unlabeler a
165− , fromColumns $ hunlabel unlabeler b
166− , fromColumns $ hunlabel unlabeler c
167− , fromColumns $ hunlabel unlabeler d
168− )
195+ )
196+ => Table context (a, b, c, d)
169197
170198
171199instance
172200 ( Table context a, Table context b, Table context c, Table context d
173201 , Table context e
174− , Labelable context
175− ) => Table context (a, b, c, d, e)
176− where
177− type Columns (a, b, c, d, e) =
178− HQuintet
179− (HLabel "fst" (Columns a))
180− (HLabel "snd" (Columns b))
181− (HLabel "trd" (Columns c))
182− (HLabel "frt" (Columns d))
183− (HLabel "fft" (Columns e))
184− type Context (a, b, c, d, e) = Context a
185−
186− toColumns (a, b, c, d, e) = HQuintet
187− { hfst = hlabel labeler $ toColumns a
188− , hsnd = hlabel labeler $ toColumns b
189− , htrd = hlabel labeler $ toColumns c
190− , hfrt = hlabel labeler $ toColumns d
191− , hfft = hlabel labeler $ toColumns e
192− }
193− fromColumns (HQuintet a b c d e) =
194− ( fromColumns $ hunlabel unlabeler a
195− , fromColumns $ hunlabel unlabeler b
196− , fromColumns $ hunlabel unlabeler c
197− , fromColumns $ hunlabel unlabeler d
198− , fromColumns $ hunlabel unlabeler e
199− )
200−
201−
202−instance Table Expr Opaque where
203− type Columns Opaque = HType Opaque
204− type Context Opaque = Expr
202+ )
203+ => Table context (a, b, c, d, e)
205204
206− fromColumns = error "opaque"
207− toColumns = error "opaque"
208205
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)
209211
210−instance Table context (Opaque1 context a) where
211− type Columns (Opaque1 context a) = HType Opaque
212− type Context (Opaque1 context a) = context
213212
214− fromColumns = error "opaque"
215− 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)
216218
217219
218220type 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+41−29
@@ -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
@@ -18,16 +16,20 @@ import Data.Functor.Identity ( Identity( Identity ) )
1816import Prelude
1917
2018-- rel8
21−import Rel8.Aggregate ( Aggregate, Aggregates, Col(..) )
22−import Rel8.Expr ( Expr, Col(..) )
23−import Rel8.Expr.Aggregate ( listAggExpr, nonEmptyAggExpr, sgroupByExpr )
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 )
3335import Rel8.Type.Eq ( DBEq )
@@ -35,14 +37,28 @@ import Rel8.Type.Eq ( DBEq )
3537
3638-- | Group equal tables together. This works by aggregating each column in the
3739-- given table with 'groupByExpr'.
38−groupBy :: forall exprs. EqTable exprs => exprs -> Aggregate exprs
39−groupBy (toColumns -> exprs) = fromColumns $ htabulate $ \field ->
40− case hfield dicts field of
41− Dict -> case hfield hspecs field of
42− SSpec {nullability} -> case hfield exprs field of
43− DB expr -> Aggregation $ sgroupByExpr nullability expr
44− where
45− dicts = hdicts @(Columns exprs) @(ConstrainDBType DBEq)
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
4662
4763
4864-- | Aggregate rows into a single row containing an array of all aggregated
@@ -55,26 +71,22 @@ groupBy (toColumns -> exprs) = fromColumns $ htabulate $ \field ->
5571-- items:
5672--
5773-- @
58−-- ordersWithItems :: Query (Order Expr, ListTable (Item Expr))
74+-- ordersWithItems :: Query (Order Expr, ListTable Expr (Item Expr))
5975-- ordersWithItems = do
6076-- order <- each orderSchema
6177-- items <- aggregate $ listAgg <$> itemsFromOrder order
6278-- return (order, items)
6379-- @
64−listAgg :: Table Expr exprs => exprs -> Aggregate (ListTable exprs)
80+listAgg :: Aggregates aggregates exprs => exprs -> ListTable Aggregate aggregates
6581listAgg (toColumns -> exprs) = fromColumns $
6682 hvectorize
67− (\_ (Identity (DB a)) -> Aggregation $ listAggExpr a)
83+ (\Spec {info} (Identity a) -> slistAggExpr info a)
6884 (pure exprs)
6985
7086
7187-- | Like 'listAgg', but the result is guaranteed to be a non-empty list.
72−nonEmptyAgg :: Table Expr exprs => exprs -> Aggregate (NonEmptyTable exprs)
88+nonEmptyAgg :: Aggregates aggregates exprs => exprs -> NonEmptyTable Aggregate aggregates
7389nonEmptyAgg (toColumns -> exprs) = fromColumns $
7490 hvectorize
75− (\_ (Identity (DB a)) -> Aggregation $ nonEmptyAggExpr a)
91+ (\Spec {info} (Identity a) -> snonEmptyAggExpr info a)
7692 (pure exprs)
77−
78−
79−runAggregation :: Aggregates aggregates exprs => aggregates -> Aggregate exprs
80−runAggregation = fromColumns . toColumns
src/Rel8/Table/Alternative.hs+2−2
@@ -20,8 +20,8 @@ import Rel8.Table ( Table )
2020-- | Like 'Alt' in Haskell. This class is purely a Rel8 concept, and allows you
2121-- to take a choice between two tables. See also 'AlternativeTable'.
2222--
23−-- For example, using '<|>:' on 'MaybeTable' allows you to combine two tables
24−-- and to return the first one that is a "just" MaybeTable.
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.
2525type AltTable :: (Type -> Type) -> Constraint
2626class AltTable f where
2727 -- | An associative binary operation on 'Table's.
src/Rel8/Table/Bool.hs+20−6
@@ -5,6 +5,7 @@
55module Rel8.Table.Bool
66 ( bool
77 , case_
8+ , nullable
89 )
910where
1011
@@ -12,23 +13,36 @@ where
1213import Prelude
1314
1415-- rel8
15−import Rel8.Expr ( Expr, Col(..) )
16+import Rel8.Expr ( Expr )
1617import Rel8.Expr.Bool ( boolExpr, caseExpr )
18+import Rel8.Expr.Null ( isNull, unsafeUnnullify )
1719import Rel8.Schema.HTable ( htabulate, hfield )
1820import Rel8.Table ( Table, fromColumns, toColumns )
1921
2022
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@.
2127bool :: Table Expr a => a -> a -> Expr Bool -> a
2228bool (toColumns -> false) (toColumns -> true) condition =
2329 fromColumns $ htabulate $ \field ->
2430 case (hfield false field, hfield true field) of
25− (DB falseExpr, DB trueExpr) ->
26− DB (boolExpr falseExpr trueExpr condition)
31+ (falseExpr, trueExpr) -> boolExpr falseExpr trueExpr condition
32+{-# INLINABLE bool #-}
2733
2834
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.
2938case_ :: Table Expr a => [(Expr Bool, a)] -> a -> a
3039case_ (map (fmap toColumns) -> branches) (toColumns -> fallback) =
3140 fromColumns $ htabulate $ \field -> case hfield fallback field of
32− DB fallbackExpr ->
33− case map (fmap (unDB . (`hfield` field))) branches of
34− 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+161−91
@@ -3,45 +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.Label ( Labelable, labeler, unlabeler )
29−import Rel8.Schema.Context.Nullify
30− ( Nullifiable, NullifiableEq
31− , encodeTag, decodeTag
32− , nullifier, unnullifier
33− )
40+import Rel8.Kind.Context ( Reifiable )
41+import Rel8.Schema.Context.Nullify ( Nullifiable )
42+import Rel8.Schema.Dict ( Dict( Dict ) )
3443import Rel8.Schema.HTable.Either ( HEitherTable(..) )
3544import Rel8.Schema.HTable.Identity ( HIdentity(..) )
36−import Rel8.Schema.HTable.Label ( HLabel, hlabel, hunlabel )
37−import Rel8.Schema.HTable.Nullify ( hnullify, hunnullify )
38−import Rel8.Table ( Table, Columns, Context, fromColumns, toColumns )
39−import Rel8.Table.Bool ( bool )
40−import Rel8.Table.Lifted
41− ( Table1, Columns1, ConstrainContext1, fromColumns1, toColumns1
42− , 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
4352 )
44−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 )
4559import Rel8.Table.Undefined ( undefined )
4660import Rel8.Type.Tag ( EitherTag( IsLeft, IsRight ), isLeft, isRight )
4761
@@ -50,124 +64,180 @@ import Data.Functor.Apply ( Apply, (<.>) )
5064import Data.Functor.Bind ( Bind, (>>-) )
5165
5266
53−type EitherTable :: Type -> Type -> Type
54−data EitherTable a b = EitherTable
55− { tag :: Expr EitherTag
56− , left :: a
57− , 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
5878 }
59− 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+
86+
87+instance Nullifiable context => Bifunctor (EitherTable context) where
88+ bimap f g (EitherTable tag a b) = EitherTable tag (fmap f a) (fmap g b)
6089
6190
62−instance Bifunctor EitherTable where
63− bimap f g (EitherTable tag a b) = EitherTable tag (f a) (g b)
91+instance Projectable (EitherTable context a) where
92+ project f (EitherTable tag a b) = EitherTable tag a (project f b)
6493
6594
66−instance Table Expr a => Apply (EitherTable a) where
95+instance (context ~ Expr, Table Expr a) => Apply (EitherTable context a) where
6796 EitherTable tag l1 f <.> EitherTable tag' l2 a =
68− EitherTable (tag <> tag') (bool l1 l2 (isLeft tag)) (f a)
97+ EitherTable (tag <> tag') (bool l1 l2 (isLeft tag)) (f <.> a)
6998
7099
71−instance Table Expr a => Applicative (EitherTable a) where
100+instance (context ~ Expr, Table Expr a) => Applicative (EitherTable context a) where
72101 pure = rightTable
73102 (<*>) = (<.>)
74103
75104
76−instance Table Expr a => Bind (EitherTable a) where
77− 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
78107 EitherTable tag' l2 b ->
79108 EitherTable (tag <> tag') (bool l1 l2 (isRight tag)) b
80109
81110
82−instance Table Expr a => Monad (EitherTable a) where
111+instance (context ~ Expr, Table Expr a) => Monad (EitherTable context a) where
83112 (>>=) = (>>-)
84113
85114
86−instance (Table Expr a, Table Expr b) => Semigroup (EitherTable a b) where
115+instance (context ~ Expr, Table Expr a, Table Expr b) =>
116+ Semigroup (EitherTable context a b)
117+ where
87118 a <> b = bool a b (isRightTable a)
88119
89120
90−instance Table2 EitherTable where
91− type Columns2 EitherTable = HEitherTable
92− 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+ }
93138
94− toColumns2 f g EitherTable {tag, left, right} = HEitherTable
95− { htag
96− , hleft = hnullify (nullifier (isLeft tag)) $ f left
97− , 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
98143 }
99− where
100− htag = HIdentity (encodeTag tag)
101−
102− fromColumns2 f g HEitherTable {htag = htag, hleft, hright} =
103− EitherTable
104− { tag
105− , left = f $ runIdentity $
106− hunnullify (\a -> pure . unnullifier (isLeft tag) a) hleft
107− , right = g $ runIdentity $
108− hunnullify (\a -> pure . unnullifier (isRight tag) a) hright
109− }
110− where
111− tag = decodeTag $ unHIdentity htag
112144
113− {-# INLINABLE fromColumns2 #-}
114− {-# INLINABLE toColumns2 #-}
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))
155+ }
115156
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)
161+ where
162+ err = error "Either.fromColumns: mismatch between tag and data"
116163
117−instance Table context a => Table1 (EitherTable a) where
118− type Columns1 (EitherTable a) = HEitherTable (Columns a)
119− type ConstrainContext1 (EitherTable a) = NullifiableEq (Context a)
120164
121− toColumns1 = toColumns2 toColumns
122− fromColumns1 = fromColumns2 fromColumns
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+ }
123173
124174
125−instance
126− ( Table context a, Table context b
127− , Labelable context, Nullifiable context
128− ) =>
129− Table context (EitherTable a b)
175+instance (OrdTable a, OrdTable b, context ~ Expr) =>
176+ OrdTable (EitherTable context a b)
130177 where
131− type Columns (EitherTable a b) =
132− HEitherTable (HLabel "Left" (Columns a)) (HLabel "Right" (Columns b))
133− type Context (EitherTable a b) = Context a
134−
135− toColumns =
136− toColumns2
137− (hlabel labeler . toColumns)
138− (hlabel labeler . toColumns)
139− fromColumns =
140− fromColumns2
141− (fromColumns . hunlabel unlabeler)
142− (fromColumns . hunlabel unlabeler)
178+ ordTable = HEitherTable
179+ { htag = hlabel (HIdentity Dict)
180+ , hleft = hlabel (ordTable @(Nullify context a))
181+ , hright = hlabel (ordTable @(Nullify context b))
182+ }
143183
144184
145−instance
146− ( Nullifiable from, Labelable from
147− , Nullifiable to, Labelable to
148− , Recontextualize from to a1 b1
149− , Recontextualize from to a2 b2
150− ) =>
151− Recontextualize from to (EitherTable a1 a2) (EitherTable b1 b2)
185+instance (ToExprs exprs1 a, ToExprs exprs2 b, x ~ EitherTable Expr exprs1 exprs2) =>
186+ ToExprs x (Either a b)
152187
153188
154−isLeftTable :: EitherTable a b -> Expr Bool
155−isLeftTable = isLeft . tag
189+-- | Test if an 'EitherTable' is a 'leftTable'.
190+isLeftTable :: EitherTable Expr a b -> Expr Bool
191+isLeftTable EitherTable {tag} = isLeft tag
156192
157193
158−isRightTable :: EitherTable a b -> Expr Bool
159−isRightTable = isRight . tag
194+-- | Test if an 'EitherTable' is a 'rightTable'.
195+isRightTable :: EitherTable Expr a b -> Expr Bool
196+isRightTable EitherTable {tag} = isRight tag
160197
161198
199+-- | Pattern match/eliminate an 'EitherTable', by providing mappings from a
200+-- 'leftTable' and 'rightTable'.
162201eitherTable :: Table Expr c
163− => (a -> c) -> (b -> c) -> EitherTable a b -> c
202+ => (a -> c) -> (b -> c) -> EitherTable Expr a b -> c
164203eitherTable f g EitherTable {tag, left, right} =
165− bool (f left) (g right) (isRight tag)
204+ bool (f (extract left)) (g (extract right)) (isRight tag)
205+
166206
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
167210
168−leftTable :: Table Expr b => a -> EitherTable a b
169−leftTable a = EitherTable (litExpr IsLeft) a undefined
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
215+
216+
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+ }
170229
171230
172−rightTable :: Table Expr a => b -> EitherTable a b
173−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+66−35
@@ -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
@@ -20,35 +23,71 @@ 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
26−import Rel8.Expr ( Expr, Col(..) )
30+import Rel8.Expr ( Expr )
2731import Rel8.Expr.Bool ( (||.), (&&.) )
28−import Rel8.Expr.Eq ( seq, sne )
29−import Rel8.Opaque ( Opaque )
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 )
3036import Rel8.Schema.Dict ( Dict( Dict ) )
31−import Rel8.Schema.HTable
32− ( HConstrainTable
33− , htabulateA, hfield
34− , hdicts, hspecs
35− )
36−import Rel8.Schema.Spec ( SSpec(..) )
37−import Rel8.Schema.Spec.ConstrainDBType ( ConstrainDBType )
38−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 )
3941import Rel8.Type.Eq ( DBEq )
4042
4143
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'".
4247type EqTable :: Type -> Constraint
43−class
44− ( Table Expr a
45− , HConstrainTable (Columns a) (ConstrainDBType DBEq)
46− ) => 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+
4786instance
48− ( Table Expr a
49− , HConstrainTable (Columns a) (ConstrainDBType DBEq)
50− ) => EqTable a
51−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)
5291
5392
5493-- | Compare two 'Table's for equality. This corresponds to comparing all
@@ -58,12 +97,8 @@ instance {-# OVERLAPPING #-} EqTable Opaque
5897(toColumns -> as) ==: (toColumns -> bs) =
5998 foldl1' (&&.) $ getConst $ htabulateA $ \field ->
6099 case (hfield as field, hfield bs field) of
61− (DB a, DB b) -> case hfield dicts field of
62− Dict -> case hfield specs field of
63− SSpec {nullability} -> Const (pure (seq nullability a b))
64− where
65− dicts = hdicts @(Columns a) @(ConstrainDBType DBEq)
66− specs = hspecs @(Columns a)
100+ (a, b) -> case hfield (eqTable @a) field of
101+ Dict -> Const (pure (a ==. b))
67102infix 4 ==:
68103
69104
@@ -74,12 +109,8 @@ infix 4 ==:
74109(toColumns -> as) /=: (toColumns -> bs) =
75110 foldl1' (||.) $ getConst $ htabulateA $ \field ->
76111 case (hfield as field, hfield bs field) of
77− (DB a, DB b) -> case hfield dicts field of
78− Dict -> case hfield specs field of
79− SSpec {nullability} -> Const (pure (sne nullability a b))
80− where
81− dicts = hdicts @(Columns a) @(ConstrainDBType DBEq)
82− specs = hspecs @(Columns a)
112+ (a, b) -> case hfield (eqTable @a) field of
113+ Dict -> Const (pure (a /=. b))
83114infix 4 /=:
84115
85116
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−51
@@ -1,51 +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.Expr ( Col(..) )
17−import Rel8.Kind.Necessity ( SNecessity( SOptional, SRequired ) )
18−import Rel8.Schema.HTable ( hfield, htabulate, hspecs )
19−import Rel8.Schema.Insert ( Inserts, Col(..) )
20−import Rel8.Schema.Spec ( SSpec(..) )
21−import Rel8.Table ( fromColumns, toColumns )
22−
23−
24−-- | @toInsert@ converts a 'Table' of 'Expr's into a 'Table' that can be used
25−-- with 'insert'. This will override any columns that have default values to
26−-- use exactly what is given. If you want to use default values, you can either
27−-- override the result of @toInsert@, or use 'toInsertDefaults'.
28−toInsert :: Inserts exprs inserts => exprs -> inserts
29−toInsert (toColumns -> exprs) = fromColumns $ htabulate $ \field ->
30− case hfield hspecs field of
31− SSpec {necessity} -> case hfield exprs field of
32− DB expr -> case necessity of
33− SRequired -> RequiredInsert expr
34− SOptional -> OptionalInsert (Just expr)
35−
36−
37−-- | @toInsertDefaults@ converts a 'Table' of 'Expr's into a 'Table' that can
38−-- be used with 'insert'. Any columns that have a default value will override
39−-- whatever is in the input expression.
40−--
41−-- One example where this is useful is for any table that has a special @id@
42−-- column, which has a default value to draw a new value from a sequence. If we
43−-- use 'toInsertDefaults', we can provide a dummy value that will be replaced
44−-- with a call to @DEFAULT@.
45−toInsertDefaults :: Inserts exprs inserts => exprs -> inserts
46−toInsertDefaults (toColumns -> exprs) = fromColumns $ htabulate $ \field ->
47− case hfield hspecs field of
48− SSpec {necessity} -> case hfield exprs field of
49− DB expr -> case necessity of
50− SRequired -> RequiredInsert expr
51− SOptional -> OptionalInsert Nothing
src/Rel8/Table/Lifted.hsdeleted−57
@@ -1,57 +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.Context ( Interpretation, Col )
20−import Rel8.Schema.HTable ( HTable )
21−import qualified Rel8.Schema.Kind as K
22−
23−
24−type Table1 :: (Type -> Type) -> Constraint
25−class Table1 f where
26− type Columns1 f :: K.HTable -> K.HTable
27− type ConstrainContext1 f :: K.Context -> Constraint
28− type ConstrainContext1 _ = Interpretation
29−
30− toColumns1 :: (ConstrainContext1 f context, HTable t)
31− => (a -> t (Col context))
32− -> f a
33− -> Columns1 f t (Col context)
34−
35− fromColumns1 :: (ConstrainContext1 f context, HTable t)
36− => (t (Col context) -> a)
37− -> Columns1 f t (Col context)
38− -> f a
39−
40−
41−type Table2 :: (Type -> Type -> Type) -> Constraint
42−class Table2 p where
43− type Columns2 p :: K.HTable -> K.HTable -> K.HTable
44− type ConstrainContext2 p :: K.Context -> Constraint
45− type ConstrainContext2 _ = Interpretation
46−
47− toColumns2 :: (ConstrainContext2 p context, HTable t, HTable u)
48− => (a -> t (Col context))
49− -> (b -> u (Col context))
50− -> p a b
51− -> Columns2 p t u (Col context)
52−
53− fromColumns2 :: (ConstrainContext2 p context, HTable t, HTable u)
54− => (t (Col context) -> a)
55− -> (u (Col context) -> b)
56− -> Columns2 p t u (Col context)
57− -> p a b
src/Rel8/Table/List.hs+107−21
@@ -1,63 +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 ( Expr, Col(..) )
19−import Rel8.Expr.Array ( sappend, sempty )
26+import Rel8.Expr ( Expr )
27+import Rel8.Expr.Array ( sappend, sempty, slistOf )
28+import Rel8.Schema.Dict ( Dict( Dict ) )
2029import Rel8.Schema.HTable.List ( HListTable )
21−import Rel8.Schema.HTable.Vectorize ( happend, hempty )
22−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+ )
2345import Rel8.Table.Alternative
2446 ( AltTable, (<|>:)
2547 , AlternativeTable, emptyTable
2648 )
27−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 )
2855
2956
3057-- | A @ListTable@ value contains zero or more instances of @a@. You construct
31−-- @ListTable@s with 'many' or 'listAgg'.
32−type ListTable :: Type -> Type
33−newtype ListTable a = ListTable (HListTable (Columns a) (Col (Context a)))
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))
62+
3463
64+instance Projectable (ListTable context) where
65+ project f (ListTable a) = ListTable (hproject (apply f) a)
3566
36−instance Table context a => Table context (ListTable a) where
37− type Columns (ListTable a) = HListTable (Columns a)
38− 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)
3975
4076 fromColumns = ListTable
4177 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+
4290
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))
4398
44−instance Recontextualize from to a b =>
45− Recontextualize from to (ListTable a) (ListTable b)
4699
100+instance (ToExprs exprs a, context ~ Expr) =>
101+ ToExprs (ListTable context exprs) [a]
47102
48−instance AltTable ListTable where
103+
104+instance context ~ Expr => AltTable (ListTable context) where
49105 (<|>:) = (<>)
50106
51107
52−instance AlternativeTable ListTable where
108+instance context ~ Expr => AlternativeTable (ListTable context) where
53109 emptyTable = mempty
54110
55111
56−instance Table Expr a => Semigroup (ListTable a) where
57− ListTable as <> ListTable bs = ListTable $
58− 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
59136
60137
61−instance Table Expr a => Monoid (ListTable a) where
62− mempty = ListTable $ hempty $ \nullability info ->
63− 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+132−90
@@ -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.Label ( Labelable, labeler, unlabeler )
33−import Rel8.Schema.Context.Nullify
34− ( Nullifiable
35− , encodeTag, decodeTag
36− , nullifier, unnullifier
37− )
41+import Rel8.Kind.Context ( Reifiable )
42+import Rel8.Schema.Dict ( Dict( Dict ) )
43+import qualified Rel8.Schema.Kind as K
3844import Rel8.Schema.HTable.Identity ( HIdentity(..) )
39−import Rel8.Schema.HTable.Label ( HLabel, hlabel, hunlabel )
45+import Rel8.Schema.HTable.Label ( hlabel, hunlabel )
4046import Rel8.Schema.HTable.Maybe ( HMaybeTable(..) )
41−import Rel8.Schema.HTable.Nullify ( hnullify, hunnullify )
42−import Rel8.Schema.Nullability
43− ( Nullify
44− , Nullability( Nullable, NonNullable )
45− , Sql, 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 ) )
@@ -71,134 +79,168 @@ import Data.Functor.Bind ( Bind, (>>-) )
7179-- entirely of nulls, you can't distinguish if you matched an all null row, or
7280-- if the match failed. For this reason @MaybeTable@ contains an extra field -
7381-- a "nullTag" - to track whether or not the outer join produced any rows.
74−type MaybeTable :: Type -> Type
75−data MaybeTable a = MaybeTable
76− { tag :: Expr (Maybe MaybeTag)
77− , just :: a
82+type MaybeTable :: K.Context -> Type -> Type
83+data MaybeTable context a = MaybeTable
84+ { tag :: context (Maybe MaybeTag)
85+ , just :: Nullify context a
7886 }
79− 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)
8092
8193
82−instance Apply MaybeTable where
83− 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)
8496
8597
8698-- | Has the same behavior as the @Applicative@ instance for @Maybe@. See also:
87−-- 'traverseMaybeTable'.
88−instance Applicative MaybeTable where
99+-- 'Rel8.traverseMaybeTable'.
100+instance context ~ Expr => Applicative (MaybeTable context) where
89101 (<*>) = (<.>)
90102 pure = justTable
91103
92104
93−instance Bind MaybeTable where
94− 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
95107 MaybeTable tag' b -> MaybeTable (tag <> tag') b
96108
97109
98−-- | Has the same behavior as the @Monad@ instance for @Maybe@. See also:
99−-- 'bindMaybeTable'.
100−instance Monad MaybeTable where
110+-- | Has the same behavior as the @Monad@ instance for @Maybe@.
111+instance context ~ Expr => Monad (MaybeTable context) where
101112 (>>=) = (>>-)
102113
103114
104−instance AltTable MaybeTable where
105− ma@(MaybeTable tag a) <|>: MaybeTable tag' b = MaybeTable
106− { tag = boolExpr tag tag' condition
107− , just = bool a b condition
108− }
109− where
110− condition = isNothingTable ma
115+instance context ~ Expr => AltTable (MaybeTable context) where
116+ ma <|>: mb = bool ma mb (isNothingTable ma)
111117
112118
113−instance AlternativeTable MaybeTable where
119+instance context ~ Expr => AlternativeTable (MaybeTable context) where
114120 emptyTable = nothingTable
115121
116122
117−instance (Table Expr a, Semigroup a) => Semigroup (MaybeTable a) where
123+instance (context ~ Expr, Table Expr a, Semigroup a) =>
124+ Semigroup (MaybeTable context a)
125+ where
118126 ma <> mb = maybeTable mb (\a -> maybeTable ma (justTable . (a <>)) mb) ma
119127
120128
121−instance (Table Expr a, Semigroup a) => Monoid (MaybeTable a) where
129+instance (context ~ Expr, Table Expr a, Semigroup a) =>
130+ Monoid (MaybeTable context a)
131+ where
122132 mempty = nothingTable
123133
124134
125−instance Table1 MaybeTable where
126− type Columns1 MaybeTable = HMaybeTable
127− 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+ }
128147
129− toColumns1 f MaybeTable {tag, just} = HMaybeTable
130− { htag
131− , hjust = hnullify (nullifier (isNonNull tag)) $ f just
148+ fromColumns HMaybeTable {htag, hjust} = MaybeTable
149+ { tag = unHIdentity $ hunlabel htag
150+ , just = fromColumns $ hunlabel hjust
132151 }
133− where
134− htag = HIdentity (encodeTag tag)
135152
136− fromColumns1 f HMaybeTable {htag = HIdentity htag, hjust} = MaybeTable
137− { tag
138− , just = f $ runIdentity $
139− 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)
140156 }
157+
158+ fromResult HMaybeTable {htag, hjust} = case hunlabel htag of
159+ HIdentity (Identity tag) -> tag $>
160+ fromMaybe err (fromResult @_ @(Nullify context a) (hunlabel hjust))
141161 where
142− tag = decodeTag htag
162+ err = error "Maybe.fromColumns: mismatch between tag and data"
143163
144− {-# INLINABLE fromColumns1 #-}
145− {-# INLINABLE toColumns1 #-}
146164
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+ }
147170
148−instance
149− ( Table context a
150− , Labelable context, Nullifiable context
151− ) => Table context (MaybeTable a)
152− where
153− type Columns (MaybeTable a) = HMaybeTable (HLabel "Just" (Columns a))
154− type Context (MaybeTable a) = Context a
155171
156− toColumns = toColumns1 (hlabel labeler . toColumns)
157− 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+ }
158177
159178
160−instance
161− ( Labelable from, Nullifiable from
162− , Labelable to, Nullifiable to
163− , Recontextualize from to a b
164− ) => Recontextualize from to (MaybeTable a) (MaybeTable b)
179+instance (ToExprs exprs a, context ~ Expr) =>
180+ ToExprs (MaybeTable context exprs) (Maybe a)
165181
166182
167−-- | Check if a @MaybeTable@ is absent of any row.. Like 'isNothing'.
168−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
169185isNothingTable (MaybeTable tag _) = isNull tag
170186
171187
172−-- | Check if a @MaybeTable@ contains a row. Like 'isJust'.
173−isJustTable :: MaybeTable a -> Expr Bool
188+-- | Check if a @MaybeTable@ contains a row. Like 'Data.Maybe.isJust'.
189+isJustTable :: MaybeTable Expr a -> Expr Bool
174190isJustTable (MaybeTable tag _) = isNonNull tag
175191
176192
177193-- | Perform case analysis on a 'MaybeTable'. Like 'maybe'.
178−maybeTable :: Table Expr b => b -> (a -> b) -> MaybeTable a -> b
179−maybeTable b f ma@(MaybeTable _ a) = bool (f a) b (isNothingTable ma)
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 #-}
180197
181198
182199-- | The null table. Like 'Nothing'.
183−nothingTable :: Table Expr a => MaybeTable a
184−nothingTable = MaybeTable null undefined
200+nothingTable :: Table Expr a => MaybeTable Expr a
201+nothingTable = MaybeTable null (pure undefined)
185202
186203
187204-- | Lift any table into 'MaybeTable'. Like 'Just'. Note you can also use
188205-- 'pure'.
189−justTable :: a -> MaybeTable a
190−justTable = MaybeTable (nullify (litExpr IsJust))
206+justTable :: a -> MaybeTable Expr a
207+justTable = MaybeTable mempty . pure
208+
209+
210+-- | 'Data.Maybe.fromMaybe' for 'MaybeTable's.
211+fromMaybeTable :: Table Expr a => a -> MaybeTable Expr a -> a
212+fromMaybeTable fallback = maybeTable fallback id
191213
192214
193215-- | Project a single expression out of a 'MaybeTable'. You can think of this
194216-- operator like the '$' operator, but it also has the ability to return
195217-- @null@.
196−--
197−-- >>> select c $ fmap (fst $?) (optional (values [lit (True, False)]))
198−-- [Just True]
199218($?) :: forall a b. Sql DBType b
200− => (a -> Expr b) -> MaybeTable a -> Expr (Nullify b)
201−f $? ma@(MaybeTable _ a) = case nullabilization @b of
202− Nullable -> boolExpr (f a) null (isNothingTable ma)
203− NonNullable -> boolExpr (nullify (f a)) null (isNothingTable ma)
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)
204223infixl 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+37−22
@@ -1,14 +1,17 @@
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
913 ( namesFromLabels
1014 , namesFromLabelsWith
11− , showExprs
1215 , showLabels
1316 , showNames
1417 )
@@ -17,48 +20,60 @@ where
1720-- base
1821import Data.Foldable ( fold )
1922import Data.Functor.Const ( Const( Const ), getConst )
20−import Data.List.NonEmpty ( NonEmpty, intersperse )
23+import Data.List.NonEmpty ( NonEmpty, intersperse, nonEmpty )
24+import Data.Maybe ( fromMaybe )
2125import Prelude
2226
23−-- casing
24−import Text.Casing ( quietSnake )
25−
2627-- rel8
27−import Rel8.Expr ( Expr, Col(..) )
28−import Rel8.Kind.Labels ( renderLabels )
2928import Rel8.Schema.HTable ( htabulate, htabulateA, hfield, hspecs )
30−import Rel8.Schema.Name ( Name, Col(..) )
31−import Rel8.Schema.Spec ( SSpec(..) )
32−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(..) )
3332
3433
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'.
3538namesFromLabels :: Table Name a => a
3639namesFromLabels = namesFromLabelsWith go
3740 where
38− go = fold . intersperse "/" . fmap quietSnake
41+ go = fold . intersperse "/"
3942
4043
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.
4159namesFromLabelsWith :: Table Name a
4260 => (NonEmpty String -> String) -> a
4361namesFromLabelsWith f = fromColumns $ htabulate $ \field ->
4462 case hfield hspecs field of
45− SSpec {labels} -> NameCol (f (renderLabels labels))
46−
47−
48−showExprs :: Table Expr a => a -> [(String, String)]
49−showExprs as = case (namesFromLabels, toColumns as) of
50− (names, exprs) -> getConst $ htabulateA $ \field ->
51− case (hfield names field, hfield exprs field) of
52− (NameCol name, DB expr) -> Const [(name, show expr)]
63+ Spec {labels} -> Name (f (renderLabels labels))
5364
5465
5566showLabels :: forall a. Table (Context a) a => a -> [NonEmpty String]
5667showLabels _ = getConst $
5768 htabulateA @(Columns a) $ \field -> case hfield hspecs field of
58− SSpec {labels} -> Const [renderLabels labels]
69+ Spec {labels} -> Const (pure (renderLabels labels))
5970
6071
61−showNames :: forall a. Table Name a => a -> [String]
72+showNames :: forall a. Table Name a => a -> NonEmpty String
6273showNames (toColumns -> names) = getConst $
6374 htabulateA @(Columns a) $ \field -> case hfield names field of
64− NameCol 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+110−19
@@ -1,52 +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 ( Expr, Col(..) )
19−import Rel8.Expr.Array ( sappend1 )
27+import Rel8.Expr ( Expr )
28+import Rel8.Expr.Array ( sappend1, snonEmptyOf )
29+import Rel8.Schema.Dict ( Dict( Dict ) )
2030import Rel8.Schema.HTable.NonEmpty ( HNonEmptyTable )
21−import Rel8.Schema.HTable.Vectorize ( happend )
22−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+ )
2346import Rel8.Table.Alternative ( AltTable, (<|>:) )
24−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 )
2553
2654
2755-- | A @NonEmptyTable@ value contains one or more instances of @a@. You
28−-- construct @NonEmptyTable@s with 'some' or 'nonEmptyAgg'.
29−type NonEmptyTable :: Type -> Type
30−newtype NonEmptyTable a =
31− NonEmptyTable (HNonEmptyTable (Columns a) (Col (Context a)))
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))
60+
3261
62+instance Projectable (NonEmptyTable context) where
63+ project f (NonEmptyTable a) = NonEmptyTable (hproject (apply f) a)
3364
34−instance Table context a => Table context (NonEmptyTable a) where
35− type Columns (NonEmptyTable a) = HNonEmptyTable (Columns a)
36− 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)
3774
3875 fromColumns = NonEmptyTable
3976 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+
4091
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))
41101
42−instance Recontextualize from to a b =>
43− Recontextualize from to (NonEmptyTable a) (NonEmptyTable b)
44102
103+instance (ToExprs exprs a, context ~ Expr) =>
104+ ToExprs (NonEmptyTable context exprs) (NonEmpty a)
45105
46−instance AltTable NonEmptyTable where
106+
107+instance context ~ Expr => AltTable (NonEmptyTable context) where
47108 (<|>:) = (<>)
48109
49110
50−instance Table Expr a => Semigroup (NonEmptyTable a) where
111+instance (Table Expr a, context ~ Expr) => Semigroup (NonEmptyTable context a)
112+ where
51113 NonEmptyTable as <> NonEmptyTable bs = NonEmptyTable $
52− 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+94−74
@@ -1,130 +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 ) )
36−import Rel8.Expr ( Expr, Col(..) )
45+import Rel8.Aggregate ( Aggregate( Aggregate ), Aggregates )
46+import Rel8.Expr ( Expr )
3747import Rel8.Expr.Opaleye
38− ( scastExpr
39− , fromPrimExpr, toPrimExpr
40− , traversePrimExpr
41− , fromColumn, toColumn
48+ ( fromPrimExpr, toPrimExpr
49+ , scastExpr, traverseFieldP
4250 )
43−import Rel8.Kind.Necessity ( SNecessity( SRequired, SOptional ) )
44−import Rel8.Schema.HTable ( htabulateA, hfield, htraverse, hspecs )
45−import Rel8.Schema.Insert ( Insert, Inserts, Col(..) )
46−import Rel8.Schema.Name ( Name, Selects, Col(..) )
47−import Rel8.Schema.Spec ( SSpec(..) )
48−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 )
4956import Rel8.Table ( Table, fromColumns, toColumns )
50−import Rel8.Table.Undefined ( undefined )
57+import Rel8.Type.Information ( typeName )
5158
5259-- semigroupoids
5360import 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+
5469
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)
5576
56−aggregator :: Opaleye.Aggregator (Aggregate exprs) exprs
57−aggregator = Opaleye.Aggregator $ Opaleye.PackMap $
58− \f (Aggregate (Opaleye.Aggregator (Opaleye.PackMap inner))) -> inner f ()
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))
5983
6084
6185binaryspec :: Table Expr a => Opaleye.Binaryspec a a
62−binaryspec = Opaleye.Binaryspec $ Opaleye.PackMap $ \f (as, bs) ->
63− fmap fromColumns $ unwrapApplicative $ htabulateA $ \field ->
64− WrapApplicative $
65− case (hfield (toColumns as) field, hfield (toColumns bs) field) of
66− (DB a, DB b) -> DB . fromPrimExpr <$> f (toPrimExpr a, toPrimExpr b)
86+binaryspec = fromOpaleyespec Opaleye.binaryspecField
6787
6888
6989distinctspec :: Table Expr a => Opaleye.Distinctspec a a
70−distinctspec =
71− Opaleye.Distinctspec $ Opaleye.Aggregator $ Opaleye.PackMap $ \f ->
72− fmap fromColumns .
73− unwrapApplicative .
74− htraverse
75− (\(DB a) ->
76− WrapApplicative $ DB . fromPrimExpr <$> f (Nothing, toPrimExpr a)) .
77− toColumns
78−
79−
80−table ::(Selects names exprs, Inserts exprs inserts)
81− => TableSchema names -> Opaleye.Table inserts exprs
90+distinctspec = fromOpaleyespec Opaleye.distinctspecField
91+
92+
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))
97+
98+
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
82107table (TableSchema name schema columns) =
83− Opaleye.Table qualified (tableFields columns)
84− where
85− qualified = case schema of
86− Nothing -> name
87− Just qualifier -> qualifier <> "." <> name
108+ case schema of
109+ Nothing -> Opaleye.table name (tableFields columns)
110+ Just schemaName -> Opaleye.tableWithSchema schemaName name (tableFields columns)
88111
89112
90−tableFields :: (Selects names exprs, Inserts exprs inserts)
91− => names -> Opaleye.TableFields inserts exprs
113+tableFields :: Selects names exprs
114+ => names -> Opaleye.TableFields exprs exprs
92115tableFields (toColumns -> names) = dimap toColumns fromColumns $
93116 unwrapApplicative $ htabulateA $ \field -> WrapApplicative $
94− case hfield hspecs field of
95− specs -> case hfield names field of
96− name -> lmap (`hfield` field) (go specs name)
117+ case hfield names field of
118+ name -> lmap (`hfield` field) (go name)
97119 where
98− go :: SSpec spec -> Col Name spec -> Opaleye.TableFields (Col Insert spec) (Col Expr spec)
99− go SSpec {necessity, info, nullability} (NameCol name) =
100− case necessity of
101− SRequired ->
102− lmap (\(RequiredInsert a) -> toColumn $ toPrimExpr a) $
103− DB . scastExpr nullability info . fromPrimExpr . fromColumn <$>
104− Opaleye.requiredTableField name
105− SOptional ->
106− lmap (\(OptionalInsert ma) -> toColumn . toPrimExpr <$> ma) $
107− DB . scastExpr nullability info . fromPrimExpr . fromColumn <$>
108− Opaleye.optionalTableField name
120+ go :: Name a -> Opaleye.TableFields (Expr a) (Expr a)
121+ go (Name name) =
122+ traverseFieldP $
123+ Opaleye.requiredTableField name
109124
110125
111126unpackspec :: Table Expr a => Opaleye.Unpackspec a a
112−unpackspec = Opaleye.Unpackspec $ Opaleye.PackMap $ \f ->
113− fmap fromColumns .
114− unwrapApplicative .
115− htraverse (\(DB a) -> WrapApplicative $ DB <$> traversePrimExpr f a) .
116− toColumns
127+unpackspec = fromOpaleyespec Opaleye.unpackspecField
117128{-# INLINABLE unpackspec #-}
118129
119130
120−valuesspec :: Table Expr a => Opaleye.ValuesspecSafe a a
121−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
122141
123142
124−toPackMap :: Table Expr a
125− => a -> Opaleye.PackMap Opaleye.PrimExpr Opaleye.PrimExpr () a
126−toPackMap as = Opaleye.PackMap $ \f () ->
127− fmap fromColumns $
128− unwrapApplicative .
129− htraverse (\(DB a) -> WrapApplicative $ DB <$> traversePrimExpr f a) $
130− 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+71−49
@@ -1,39 +1,41 @@
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
23−import Rel8.Expr ( Expr, Col(..) )
27+import 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 )
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 )
2834import Rel8.Schema.Dict ( Dict( Dict ) )
29−import Rel8.Schema.HTable
30− ( HConstrainTable
31− , htabulateA, hfield
32− , hdicts, hspecs
33− )
34−import Rel8.Schema.Spec ( SSpec(..) )
35−import Rel8.Schema.Spec.ConstrainDBType ( ConstrainDBType )
36−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 )
3739import Rel8.Table.Bool ( bool )
3840import Rel8.Table.Eq ( EqTable )
3941import Rel8.Type.Ord ( DBOrd )
@@ -43,15 +45,51 @@ import Rel8.Type.Ord ( DBOrd )
4345-- by their lexicographic ordering of all columns, so this class means "all
4446-- columns in a 'Table' have an instance of 'DBOrd'".
4547type OrdTable :: Type -> Constraint
46−class
47− ( EqTable a
48− , HConstrainTable (Columns a) (ConstrainDBType DBOrd)
49− ) => 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+
5082instance
51− ( EqTable a
52− , HConstrainTable (Columns a) (ConstrainDBType DBOrd)
53− ) => OrdTable a
54−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)
5593
5694
5795-- | Test if one 'Table' sorts before another. Corresponds to comparing all
@@ -60,13 +98,9 @@ instance {-# OVERLAPPING #-} OrdTable Opaque
6098(toColumns -> as) <: (toColumns -> bs) =
6199 foldr @[] go false $ getConst $ htabulateA $ \field ->
62100 case (hfield as field, hfield bs field) of
63− (DB a, DB b) -> case hfield dicts field of
64− Dict -> case hfield specs field of
65− SSpec {nullability} ->
66− 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)]
67103 where
68− dicts = hdicts @(Columns a) @(ConstrainDBType DBOrd)
69− specs = hspecs @(Columns a)
70104 go (lt, eq) a = lt ||. (eq &&. a)
71105infix 4 <:
72106
@@ -77,13 +111,9 @@ infix 4 <:
77111(toColumns -> as) <=: (toColumns -> bs) =
78112 foldr @[] go true $ getConst $ htabulateA $ \field ->
79113 case (hfield as field, hfield bs field) of
80− (DB a, DB b) -> case hfield dicts field of
81− Dict -> case hfield specs field of
82− SSpec {nullability} ->
83− 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)]
84116 where
85− dicts = hdicts @(Columns a) @(ConstrainDBType DBOrd)
86− specs = hspecs @(Columns a)
87117 go (lt, eq) a = lt ||. (eq &&. a)
88118infix 4 <=:
89119
@@ -94,13 +124,9 @@ infix 4 <=:
94124(toColumns -> as) >: (toColumns -> bs) =
95125 foldr @[] go false $ getConst $ htabulateA $ \field ->
96126 case (hfield as field, hfield bs field) of
97− (DB a, DB b) -> case hfield dicts field of
98− Dict -> case hfield specs field of
99− SSpec {nullability} ->
100− 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)]
101129 where
102− dicts = hdicts @(Columns a) @(ConstrainDBType DBOrd)
103− specs = hspecs @(Columns a)
104130 go (gt, eq) a = gt ||. (eq &&. a)
105131infix 4 >:
106132
@@ -111,22 +137,18 @@ infix 4 >:
111137(toColumns -> as) >=: (toColumns -> bs) =
112138 foldr @[] go true $ getConst $ htabulateA $ \field ->
113139 case (hfield as field, hfield bs field) of
114− (DB a, DB b) -> case hfield dicts field of
115− Dict -> case hfield specs field of
116− SSpec {nullability} ->
117− 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)]
118142 where
119− dicts = hdicts @(Columns a) @(ConstrainDBType DBOrd)
120− specs = hspecs @(Columns a)
121143 go (gt, eq) a = gt ||. (eq &&. a)
122144infix 4 >=:
123145
124146
125147-- | Given two 'Table's, return the table that sorts before the other.
126148least :: OrdTable a => a -> a -> a
127−least a b = bool a b (a <: b)
149+least a b = bool b a (a <: b)
128150
129151
130152-- | Given two 'Table's, return the table that sorts after the other.
131153greatest :: OrdTable a => a -> a -> a
132−greatest a b = bool a b (a >: b)
154+greatest a b = bool b a (a >: b)
src/Rel8/Table/Order.hs+16−20
@@ -1,3 +1,4 @@
1+{-# language DataKinds #-}
12{-# language NamedFieldPuns #-}
23{-# language ScopedTypeVariables #-}
34{-# language TypeApplications #-}
@@ -15,17 +16,14 @@ import Data.Functor.Contravariant ( (>$<), contramap )
1516import Prelude
1617
1718-- rel8
18−import Rel8.Expr ( unDB )
1919import Rel8.Expr.Order ( asc, desc, nullsFirst, nullsLast )
2020import Rel8.Order ( Order )
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
3129-- | Construct an 'Order' for a 'Table' by sorting all columns into ascending
@@ -33,12 +31,11 @@ import Rel8.Type.Ord
3331ascTable :: forall a. OrdTable a => Order a
3432ascTable = contramap toColumns $ getConst $
3533 htabulateA @(Columns a) $ \field -> case hfield hspecs field of
36− SSpec {nullability} -> case hfield ords field of
37− Dict -> Const $ unDB . (`hfield` field) >$< case nullability of
38− Nullable -> nullsFirst asc
39− NonNullable -> asc
40− where
41− 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
4239
4340
4441-- | Construct an 'Order' for a 'Table' by sorting all columns into descending
@@ -46,9 +43,8 @@ ascTable = contramap toColumns $ getConst $
4643descTable :: forall a. OrdTable a => Order a
4744descTable = contramap toColumns $ getConst $
4845 htabulateA @(Columns a) $ \field -> case hfield hspecs field of
49− SSpec {nullability} -> case hfield ords field of
50− Dict -> Const $ unDB . (`hfield` field) >$< case nullability of
51− Nullable -> nullsLast desc
52− NonNullable -> desc
53− where
54− 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−144
@@ -1,144 +0,0 @@
1−{-# language DataKinds #-}
2−{-# language FlexibleInstances #-}
3−{-# language FunctionalDependencies #-}
4−{-# language StandaloneKindSignatures #-}
5−{-# language TypeFamilies #-}
6−{-# language UndecidableInstances #-}
7−{-# language UndecidableSuperClasses #-}
8−
9−module Rel8.Table.Recontextualize
10− ( Recontextualize
11− )
12−where
13−
14−-- base
15−import Data.Functor.Identity ( Identity )
16−import Data.Kind ( Constraint, Type )
17−import Prelude ()
18−
19−-- rel8
20−import Rel8.Opaque ( Opaque1 )
21−import Rel8.Schema.Context ( Col )
22−import Rel8.Schema.Context.Label ( Labelable )
23−import Rel8.Schema.HTable ( HTable )
24−import qualified Rel8.Schema.Kind as K
25−import Rel8.Schema.Nullability ( Sql )
26−import Rel8.Schema.Spec ( KnownSpec )
27−import Rel8.Table ( Table, Congruent )
28−import Rel8.Type ( DBType )
29−
30−
31−type Recontextualize :: K.Context -> K.Context -> Type -> Type -> Constraint
32−class
33− ( Table from a
34− , Table to b
35− , Congruent a b
36− , Recontextualize from from a a
37− , Recontextualize to to b b
38− , Recontextualize to from b a
39− ) => Recontextualize from to a b
40− | a -> from
41− , b -> to
42− , a to -> b
43− , b from -> a
44−
45−
46−instance KnownSpec spec =>
47− Recontextualize from to (Col from spec) (Col to spec)
48−
49−
50−{-
51−instance Sql DBType a =>
52− Recontextualize Aggregate Insertion (Aggregate (Expr a)) (Insertion a)
53−
54−
55−instance Sql DBType a => Recontextualize Expr Insertion (Expr a) (Insertion a)
56−-}
57−
58−
59−instance Sql DBType a => Recontextualize Identity Identity (Identity a) (Identity a)
60−
61−
62−{-
63−instance Sql DBType a =>
64− Recontextualize Identity Insertion (Identity a) (Insertion a)
65−
66−
67−instance Sql DBType a =>
68− Recontextualize Insertion Aggregate (Insertion a) (Aggregate (Expr a))
69−
70−
71−instance Sql DBType a => Recontextualize Insertion Expr (Insertion a) (Expr a)
72−
73−
74−instance Sql DBType a =>
75− Recontextualize Insertion Identity (Insertion a) (Identity a)
76−
77−
78−instance Sql DBType a => Recontextualize Insertion Insertion (Insertion a) (Insertion a)
79−
80−
81−instance Sql DBType a => Recontextualize Insertion Name (Insertion a) (Name a)
82−
83−
84−instance Sql DBType a => Recontextualize Name Insertion (Name a) (Insertion a)
85−-}
86−
87−
88−instance Recontextualize from to (Opaque1 from a) (Opaque1 to a)
89−
90−
91−instance HTable t => Recontextualize from to (t (Col from)) (t (Col to))
92−
93−
94−instance
95− ( Table from (t from)
96− , Table to (t to)
97− , Congruent (t from) (t to)
98− ) => Recontextualize from to (t from) (t to)
99−
100−
101−instance
102− ( Recontextualize from to a1 b1
103− , Recontextualize from to a2 b2
104− , Labelable from
105− , Labelable to
106− ) => Recontextualize from to (a1, a2) (b1, b2)
107−
108−
109−instance
110− ( Recontextualize from to a1 b1
111− , Recontextualize from to a2 b2
112− , Recontextualize from to a3 b3
113− , Labelable from, Labelable to
114− ) => Recontextualize from to (a1, a2, a3) (b1, b2, b3)
115−
116−
117−instance
118− ( Recontextualize from to a1 b1
119− , Recontextualize from to a2 b2
120− , Recontextualize from to a3 b3
121− , Recontextualize from to a4 b4
122− , Labelable from, Labelable to
123− ) => Recontextualize from to (a1, a2, a3, a4) (b1, b2, b3, b4)
124−
125−
126−instance
127− ( Recontextualize from to a1 b1
128− , Recontextualize from to a2 b2
129− , Recontextualize from to a3 b3
130− , Recontextualize from to a4 b4
131− , Recontextualize from to a5 b5
132− , Labelable from, Labelable to
133− ) => Recontextualize from to (a1, a2, a3, a4, a5) (b1, b2, b3, b4, b5)
134−
135−
136−{-
137−
138−-- | @Inserts a b@ means that the columns in @a@ are compatible for inserting
139−-- with the table @b@.
140−type Inserts :: Type -> Type -> Constraint
141−class Recontextualize Expr Insertion exprs inserts => Inserts exprs inserts
142−instance Recontextualize Expr Insertion exprs inserts => Inserts exprs inserts
143−instance {-# OVERLAPPING #-} Inserts (Opaque1 Expr Opaque) (Opaque1 Insertion Opaque)
144−-}
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+70−373
@@ -1,6 +1,4 @@
11{-# language AllowAmbiguousTypes #-}
2−{-# language DataKinds #-}
3−{-# language DisambiguateRecordFields #-}
42{-# language FlexibleContexts #-}
53{-# language FlexibleInstances #-}
64{-# language FunctionalDependencies #-}
@@ -9,17 +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 )
22−import Data.Functor.Identity ( Identity )
19+import Data.Functor.Identity ( Identity( Identity ) )
2320import Data.Kind ( Constraint, Type )
2421import Data.List.NonEmpty ( NonEmpty )
2522import Prelude
@@ -28,424 +25,124 @@ import Prelude
2825import qualified Hasql.Decoders as Hasql
2926
3027-- rel8
31−import Rel8.Expr ( Expr, Encodes, Col(..) )
28+import Rel8.Expr ( Expr )
3229import Rel8.Expr.Serialize ( slitExpr, sparseValue )
33−import Rel8.Opaque ( Opaque )
34−import Rel8.Schema.Context ( Col(..) )
35−import Rel8.Schema.Context.Identity
36− ( fromHEitherTable, toHEitherTable
37− , fromHListTable, toHListTable
38− , fromHMaybeTable, toHMaybeTable
39− , fromHNonEmptyTable, toHNonEmptyTable
40− , fromHTheseTable, toHTheseTable
41− )
42−import Rel8.Schema.Context.Label ( labeler, unlabeler )
4330import Rel8.Schema.HTable ( HTable, htabulate, htabulateA, hfield, hspecs )
44−import Rel8.Schema.HTable.Label ( hlabel, hunlabel )
45−import Rel8.Schema.HTable.Quartet ( HQuartet(..) )
46−import Rel8.Schema.HTable.Quintet ( HQuintet(..) )
47−import Rel8.Schema.HTable.Pair ( HPair(..) )
48−import Rel8.Schema.HTable.Trio ( HTrio(..) )
49−import Rel8.Schema.HTable.Type ( HType(..) )
50−import Rel8.Schema.Nullability ( IsMaybe, Sql )
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.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 )
5835import Rel8.Type ( DBType )
5936
6037-- semigroupoids
6138import Data.Functor.Apply ( WrappedApplicative(..) )
6239
63−-- these
64−import Data.These ( These )
65−
66−
67−type IsPlainColumn :: Type -> Bool
68−type family IsPlainColumn a where
69− IsPlainColumn (Either _ _) = 'False
70− IsPlainColumn [_] = 'False
71− IsPlainColumn (Maybe _) = 'False
72− IsPlainColumn (NonEmpty _) = 'False
73− IsPlainColumn (These _ _) = 'False
74− IsPlainColumn (_, _) = 'False
75− IsPlainColumn (_, _, _) = 'False
76− IsPlainColumn (_, _, _, _) = 'False
77− IsPlainColumn (_, _, _, _, _) = 'False
78− IsPlainColumn (_ Identity) = 'False
79− IsPlainColumn (_ (Col Identity _)) = 'False
80− IsPlainColumn (Identity _) = 'False
81− IsPlainColumn _ = 'True
82−
83−
84−type IsTabular :: Type -> Bool
85−type family IsTabular a where
86− IsTabular (Either _ _) = 'True
87− IsTabular [a] = IsListTabular a
88− IsTabular (Maybe a) = IsMaybeTabular a
89− IsTabular (NonEmpty a) = IsListTabular a
90− IsTabular (These _ _) = 'True
91− IsTabular (_, _) = 'True
92− IsTabular (_, _, _) = 'True
93− IsTabular (_, _, _, _) = 'True
94− IsTabular (_, _, _, _, _) = 'True
95− IsTabular (_ Identity) = 'True
96− IsTabular (_ (Col Identity)) = 'True
97− IsTabular (Col Identity _) = 'True
98− IsTabular _ = 'False
99−
100−
101−type IsTabular' :: Bool -> Type -> Bool
102−type family IsTabular' isTabular exprs where
103− IsTabular' _ (Expr _) = 'False
104− IsTabular' 'False _ = 'False
105− IsTabular' _ _ = 'True
106−
107−
108−type IsMaybeTabular :: Type -> Bool
109−type family IsMaybeTabular a where
110− IsMaybeTabular (Maybe _) = 'True
111− IsMaybeTabular a = IsTabular a
112−
113−
114−type IsListTabular :: Type -> Bool
115−type family IsListTabular a where
116− IsListTabular (Maybe a) = IsMaybeTabular a
117− IsListTabular a = IsTabular a
118−
11940
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.
12044type ToExprs :: Type -> Type -> Constraint
121−class ExprsFor (IsPlainColumn a) (IsTabular' (IsTabular a) exprs) a exprs => ToExprs a exprs
122−instance ExprsFor (IsPlainColumn a) (IsTabular' (IsTabular a) exprs) a exprs => ToExprs a exprs
123−
124−
125−fromIdentity' :: forall exprs a. ToExprs a exprs => Columns exprs (Col Identity) -> a
126−fromIdentity' = fromIdentity @(IsPlainColumn a) @_ @_ @exprs
127−
128−
129−toIdentity' :: forall exprs a. ToExprs a exprs => a -> Columns exprs (Col Identity)
130−toIdentity' = toIdentity @(IsPlainColumn a) @_ @_ @exprs
131−
132−
133−type ExprsFor :: Bool -> Bool -> Type -> Type -> Constraint
134−class (Table Expr exprs, isTabular ~ IsTabular a) =>
135− ExprsFor isPlainColumn isTabular a exprs where
136− fromIdentity :: Columns exprs (Col Identity) -> a
137− toIdentity :: a -> Columns exprs (Col Identity)
138−
139−
140−instance
141− ( DBType a
142− , IsMaybe a ~ 'False
143− , IsTabular a ~ 'False
144− , x ~ Expr a
145− )
146− => ExprsFor 'True 'False a x
147− where
148− fromIdentity (HType (Result a)) = a
149− toIdentity = HType . Result
150−
151−
152−instance
153− ( Sql DBType a
154− , IsListTabular a ~ 'False
155− , x ~ [a]
156− ) => ExprsFor 'False 'False [a] (Expr x)
157− where
158− fromIdentity (HType (Result a)) = a
159− toIdentity = HType . Result
160−
161−
162−instance
163− ( Sql DBType a
164− , isTabular ~ 'False
165− , IsMaybe a ~ 'False
166− , IsMaybeTabular a ~ 'False
167− , x ~ Maybe a
168− ) => ExprsFor 'False 'False (Maybe a) (Expr x)
169− where
170− fromIdentity (HType (Result a)) = a
171− toIdentity = HType . Result
172−
173−
174−instance
175− ( Sql DBType a
176− , IsListTabular a ~ 'False
177− , x ~ NonEmpty a
178− ) => ExprsFor 'False 'False (NonEmpty a) (Expr x)
179− where
180− fromIdentity (HType (Result a)) = a
181− toIdentity = HType . Result
182−
183−
184−instance
185− ( ToExprs a exprs
186− , IsListTabular a ~ 'False
187− ) => ExprsFor 'False 'False [a] (ListTable exprs)
188− where
189− fromIdentity = fmap (fromIdentity' @exprs) . fromHListTable
190− toIdentity = toHListTable . fmap (toIdentity' @exprs)
191−
192−
193−instance
194− ( ToExprs a exprs
195− , IsMaybeTabular a ~ 'False
196− ) => ExprsFor 'False 'False (Maybe a) (MaybeTable exprs)
197− where
198− fromIdentity =
199− fmap (fromIdentity' @exprs . hunlabel unlabeler) .
200− fromHMaybeTable
201− toIdentity =
202− toHMaybeTable .
203− fmap (hlabel labeler . toIdentity' @exprs)
204−
205−
206−instance
207− ( ToExprs a exprs
208− , IsListTabular a ~ 'False
209− ) => ExprsFor 'False 'False (NonEmpty a) (NonEmptyTable exprs)
210− where
211− fromIdentity = fmap (fromIdentity' @exprs) . fromHNonEmptyTable
212− toIdentity = toHNonEmptyTable . fmap (toIdentity' @exprs)
45+class Table Expr exprs => ToExprs exprs a
21346
21447
215−instance
216− ( ToExprs a exprs1
217− , ToExprs b exprs2
218− , isTabular ~ 'True
219− , x ~ EitherTable exprs1 exprs2
220− ) => ExprsFor 'False isTabular (Either a b) x
221− where
222− fromIdentity =
223− bimap
224− (fromIdentity' @exprs1 . hunlabel unlabeler)
225− (fromIdentity' @exprs2 . hunlabel unlabeler) .
226− fromHEitherTable
227− toIdentity =
228− toHEitherTable .
229− bimap
230− (hlabel labeler . toIdentity' @exprs1)
231− (hlabel labeler . toIdentity' @exprs2)
48+instance {-# OVERLAPPABLE #-} (Sql DBType a, x ~ Expr a) => ToExprs x a
23249
23350
234−instance
235− ( ToExprs a exprs
236− , IsListTabular a ~ 'True
237− , x ~ ListTable exprs
238− ) => ExprsFor 'False 'True [a] x
239− where
240− fromIdentity = fmap (fromIdentity' @exprs) . fromHListTable
241− toIdentity = toHListTable . fmap (toIdentity' @exprs)
51+instance (Sql DBType a, x ~ [a]) => ToExprs (Expr x) [a]
24252
24353
244−instance
245− ( ToExprs a exprs
246− , IsMaybeTabular a ~ 'True
247− , x ~ MaybeTable exprs
248− ) => ExprsFor 'False 'True (Maybe a) x
249− where
250− fromIdentity =
251− fmap (fromIdentity' @exprs . hunlabel unlabeler) .
252− fromHMaybeTable
253− toIdentity =
254− toHMaybeTable .
255− fmap (hlabel labeler . toIdentity' @exprs)
54+instance (Sql DBType a, NotNull a, x ~ Maybe a) => ToExprs (Expr x) (Maybe a)
25655
25756
258−instance
259− ( ToExprs a exprs
260− , IsListTabular a ~ 'True
261− , x ~ NonEmptyTable exprs
262− ) => ExprsFor 'False 'True (NonEmpty a) x
263− where
264− fromIdentity = fmap (fromIdentity' @exprs) . fromHNonEmptyTable
265− toIdentity = toHNonEmptyTable . fmap (toIdentity' @exprs)
57+instance (Sql DBType a, NotNull a, x ~ NonEmpty a) => ToExprs (Expr x) (NonEmpty a)
26658
26759
268−instance
269− ( ToExprs a exprs1
270− , ToExprs b exprs2
271− , isTabular ~ 'True
272− , x ~ TheseTable exprs1 exprs2
273− ) => ExprsFor 'False isTabular (These a b) x
274− where
275− fromIdentity =
276− bimap
277− (fromIdentity' @exprs1 . hunlabel unlabeler)
278− (fromIdentity' @exprs2 . hunlabel unlabeler) .
279− fromHTheseTable
280− toIdentity =
281− toHTheseTable .
282− bimap
283− (hlabel labeler . toIdentity' @exprs1)
284− (hlabel labeler . toIdentity' @exprs2)
60+instance (ToExprs exprs1 a, ToExprs exprs2 b, x ~ (exprs1, exprs2)) =>
61+ ToExprs x (a, b)
28562
28663
28764instance
288− ( ToExprs a exprs1
289− , ToExprs b exprs2
290− , isTabular ~ 'True
291− , x ~ (exprs1, exprs2)
292− ) => ExprsFor 'False isTabular (a, b) x
293− where
294− fromIdentity (HPair a b) =
295− ( fromIdentity' @exprs1 $ hunlabel unlabeler a
296− , fromIdentity' @exprs2 $ hunlabel unlabeler b
297− )
298− toIdentity (a, b) = HPair
299− { hfst = hlabel labeler $ toIdentity' @exprs1 a
300− , hsnd = hlabel labeler $ toIdentity' @exprs2 b
301− }
302−
303−
304−instance
305− ( ToExprs a exprs1
306− , ToExprs b exprs2
307− , ToExprs c exprs3
308− , isTabular ~ 'True
65+ ( ToExprs exprs1 a
66+ , ToExprs exprs2 b
67+ , ToExprs exprs3 c
30968 , x ~ (exprs1, exprs2, exprs3)
310− ) => ExprsFor 'False isTabular (a, b, c) x
311− where
312− fromIdentity (HTrio a b c) =
313− ( fromIdentity' @exprs1 $ hunlabel unlabeler a
314− , fromIdentity' @exprs2 $ hunlabel unlabeler b
315− , fromIdentity' @exprs3 $ hunlabel unlabeler c
316− )
317− toIdentity (a, b, c) = HTrio
318− { hfst = hlabel labeler $ toIdentity' @exprs1 a
319− , hsnd = hlabel labeler $ toIdentity' @exprs2 b
320− , htrd = hlabel labeler $ toIdentity' @exprs3 c
321− }
69+ )
70+ => ToExprs x (a, b, c)
32271
32372
32473instance
325− ( ToExprs a exprs1
326− , ToExprs b exprs2
327− , ToExprs c exprs3
328− , ToExprs d exprs4
329− , isTabular ~ 'True
74+ ( ToExprs exprs1 a
75+ , ToExprs exprs2 b
76+ , ToExprs exprs3 c
77+ , ToExprs exprs4 d
33078 , x ~ (exprs1, exprs2, exprs3, exprs4)
331− ) => ExprsFor 'False isTabular (a, b, c, d) x
332− where
333− fromIdentity (HQuartet a b c d) =
334− ( fromIdentity' @exprs1 $ hunlabel unlabeler a
335− , fromIdentity' @exprs2 $ hunlabel unlabeler b
336− , fromIdentity' @exprs3 $ hunlabel unlabeler c
337− , fromIdentity' @exprs4 $ hunlabel unlabeler d
338− )
339− toIdentity (a, b, c, d) = HQuartet
340− { hfst = hlabel labeler $ toIdentity' @exprs1 a
341− , hsnd = hlabel labeler $ toIdentity' @exprs2 b
342− , htrd = hlabel labeler $ toIdentity' @exprs3 c
343− , hfrt = hlabel labeler $ toIdentity' @exprs4 d
344− }
79+ )
80+ => ToExprs x (a, b, c, d)
34581
34682
34783instance
348− ( ToExprs a exprs1
349− , ToExprs b exprs2
350− , ToExprs c exprs3
351− , ToExprs d exprs4
352− , ToExprs e exprs5
353− , isTabular ~ 'True
84+ ( ToExprs exprs1 a
85+ , ToExprs exprs2 b
86+ , ToExprs exprs3 c
87+ , ToExprs exprs4 d
88+ , ToExprs exprs5 e
35489 , x ~ (exprs1, exprs2, exprs3, exprs4, exprs5)
355− ) => ExprsFor 'False isTabular (a, b, c, d, e) x
356− where
357− fromIdentity (HQuintet a b c d e) =
358− ( fromIdentity' @exprs1 $ hunlabel unlabeler a
359− , fromIdentity' @exprs2 $ hunlabel unlabeler b
360− , fromIdentity' @exprs3 $ hunlabel unlabeler c
361− , fromIdentity' @exprs4 $ hunlabel unlabeler d
362− , fromIdentity' @exprs5 $ hunlabel unlabeler e
363− )
364− toIdentity (a, b, c, d, e) = HQuintet
365− { hfst = hlabel labeler $ toIdentity' @exprs1 a
366− , hsnd = hlabel labeler $ toIdentity' @exprs2 b
367− , htrd = hlabel labeler $ toIdentity' @exprs3 c
368− , hfrt = hlabel labeler $ toIdentity' @exprs4 d
369− , hfft = hlabel labeler $ toIdentity' @exprs5 e
370− }
371−
372−
373−instance
374− ( HTable t
375− , isTabular ~ 'True
376− , result ~ Col Identity
377− , x ~ t (Col Expr)
378− ) => ExprsFor 'False isTabular (t result) x
379− where
380− fromIdentity = id
381− toIdentity = id
90+ )
91+ => ToExprs x (a, b, c, d, e)
38292
38393
38494instance
385− ( Encodes (t Identity) (t Expr)
386− , isTabular ~ 'True
387− , result ~ Identity
388− , x ~ t Expr
389− ) => ExprsFor 'False isTabular (t result) x
390− where
391− fromIdentity = fromColumns
392− toIdentity = toColumns
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)
393104
394105
395106instance
396− ( KnownSpec spec
397− , isTabular ~ 'True
398− , isSpecial ~ 'True
399− , x ~ Col Expr spec
400− ) => ExprsFor 'False isTabular (Col Identity spec) x
401− where
402− fromIdentity = fromColumns
403− toIdentity = toColumns
404−
405−
406−type FromExprs :: Type -> Type
407−type family FromExprs a where
408− FromExprs (Expr a) = a
409− FromExprs (Col Expr spec) = Col Identity spec
410− FromExprs (EitherTable a b) = Either (FromExprs a) (FromExprs b)
411− FromExprs (ListTable a) = [FromExprs a]
412− FromExprs (MaybeTable a) = Maybe (FromExprs a)
413− FromExprs (NonEmptyTable a) = NonEmpty (FromExprs a)
414− FromExprs (TheseTable a b) = These (FromExprs a) (FromExprs b)
415− FromExprs (a, b) = (FromExprs a, FromExprs b)
416− FromExprs (a, b, c) = (FromExprs a, FromExprs b, FromExprs c)
417− FromExprs (a, b, c, d) =
418− (FromExprs a, FromExprs b, FromExprs c, FromExprs d)
419− FromExprs (a, b, c, d, e) =
420− (FromExprs a, FromExprs b, FromExprs c, FromExprs d, FromExprs e)
421− FromExprs (t Expr) = t Identity
422− FromExprs (t (Col Expr)) = t (Col Identity)
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)
423117
424118
425119-- | @Serializable@ witnesses the one-to-one correspondence between the type
426120-- @sql@, which contains SQL expressions, and the type @haskell@, which
427121-- contains the Haskell decoding of rows containing @sql@ SQL expressions.
428−class (ToExprs a exprs, a ~ FromExprs exprs) => Serializable exprs a | exprs -> a
429−instance (ToExprs a exprs, a ~ FromExprs exprs) => Serializable exprs a
430−instance Serializable (Expr Opaque) Opaque
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
431126
432127
128+-- | Use @lit@ to turn literal Haskell values into expressions. @lit@ is
129+-- capable of lifting single @Expr@s to full tables.
433130lit :: forall exprs a. Serializable exprs a => a -> exprs
434−lit = fromColumns . litTable . toIdentity' @exprs
131+lit = fromColumns . litHTable . toResult @_ @exprs
435132
436133
437134parse :: forall exprs a. Serializable exprs a => Hasql.Row a
438−parse = fromIdentity' @exprs <$> parseTable
135+parse = fromResult @_ @exprs <$> parseHTable
439136
440137
441−litTable :: Encodes a b => a -> b
442−litTable (toColumns -> as) = fromColumns $ htabulate $ \field ->
138+litHTable :: HTable t => t Result -> t Expr
139+litHTable as = htabulate $ \field ->
443140 case hfield hspecs field of
444− SSpec {nullability, info} -> case hfield as field of
445− Result value -> DB (slitExpr nullability info value)
141+ Spec {nullity, info} -> case hfield as field of
142+ Identity value -> slitExpr nullity info value
446143
447144
448−parseTable :: Table Identity a => Hasql.Row a
449−parseTable = fmap fromColumns $ unwrapApplicative $ htabulateA $ \field ->
145+parseHTable :: HTable t => Hasql.Row (t Result)
146+parseHTable = unwrapApplicative $ htabulateA $ \field ->
450147 WrapApplicative $ case hfield hspecs field of
451− SSpec {nullability, info} -> Result <$> sparseValue nullability info
148+ Spec {nullity, info} -> Identity <$> sparseValue nullity info
src/Rel8/Table/These.hs+233−108
@@ -5,84 +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.Label ( Labelable, labeler, unlabeler )
33−import Rel8.Schema.Context.Nullify
34− ( Nullifiable, NullifiableEq
35− , encodeTag, decodeTag
36− , nullifier, unnullifier
37− )
38−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 )
3944import Rel8.Schema.HTable.Identity ( HIdentity(..) )
40−import Rel8.Schema.HTable.Nullify ( hnullify, hunnullify )
45+import Rel8.Schema.HTable.Maybe ( HMaybeTable(..) )
4146import Rel8.Schema.HTable.These ( HTheseTable(..) )
42−import Rel8.Table ( Table, Columns, Context, fromColumns, toColumns )
43−import Rel8.Table.Lifted
44− ( Table1, Columns1, ConstrainContext1, fromColumns1, toColumns1
45− , 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
4653 )
54+import Rel8.Table.Eq ( EqTable, eqTable )
4755import Rel8.Table.Maybe
4856 ( MaybeTable(..)
4957 , maybeTable, justTable, nothingTable
5058 , isJustTable
59+ , aggregateMaybeTable
60+ , nameMaybeTable
5161 )
52−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 )
5366import Rel8.Table.Undefined ( undefined )
67+import Rel8.Type.Tag ( MaybeTag )
5468
5569-- semigroupoids
5670import Data.Functor.Apply ( Apply, (<.>) )
5771import Data.Functor.Bind ( Bind, (>>-) )
5872
59−
60−type TheseTable :: Type -> Type -> Type
61−data TheseTable a b = TheseTable
62− { here :: MaybeTable a
63− , 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
6489 }
65− 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)
6695
6796
68−instance Bifunctor TheseTable where
97+instance Nullifiable context => Bifunctor (TheseTable context) where
6998 bimap f g (TheseTable a b) = TheseTable (fmap f a) (fmap g b)
7099
71100
72−instance (Table Expr 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
73108 fs <.> as = TheseTable
74109 { here = here fs <> here as
75110 , there = there fs <.> there as
76111 }
77112
78113
79−instance (Table Expr a, Semigroup a) => Applicative (TheseTable a)
114+instance (context ~ Expr, Table Expr a, Semigroup a) =>
115+ Applicative (TheseTable context a)
80116 where
81117 pure = thatTable
82118 (<*>) = (<.>)
83119
84120
85−instance (Table Expr a, Semigroup a) => Bind (TheseTable a) where
121+instance (context ~ Expr, Table Expr a, Semigroup a) =>
122+ Bind (TheseTable context a)
123+ where
86124 TheseTable here1 ma >>- f = case ma >>- f' of
87125 mtb -> TheseTable
88126 { here = maybeTable here1 ((here1 <>) . fst) mtb
@@ -93,12 +131,14 @@ instance (Table Expr a, Semigroup a) => Bind (TheseTable a) where
93131 TheseTable here2 mb -> (here2,) <$> mb
94132
95133
96−instance (Table Expr a, Semigroup a) => Monad (TheseTable a) where
134+instance (context ~ Expr, Table Expr a, Semigroup a) =>
135+ Monad (TheseTable context a)
136+ where
97137 (>>=) = (>>-)
98138
99139
100−instance (Table Expr a, Table Expr b, Semigroup a, Semigroup b) =>
101− Semigroup (TheseTable a b)
140+instance (context ~ Expr, Table Expr a, Table Expr b, Semigroup a, Semigroup b) =>
141+ Semigroup (TheseTable context a b)
102142 where
103143 a <> b = TheseTable
104144 { here = here a <> here b
@@ -106,127 +146,212 @@ instance (Table Expr a, Table Expr b, Semigroup a, Semigroup b) =>
106146 }
107147
108148
109−instance Table2 TheseTable where
110− type Columns2 TheseTable = HTheseTable
111− type ConstrainContext2 TheseTable = Nullifiable
112−
113− toColumns2 f g TheseTable {here, there} = HTheseTable
114− { hhereTag = HIdentity $ encodeTag (tag here)
115− , hhere = hnullify (nullifier (isNonNull (tag here))) $ f (just here)
116− , hthereTag = HIdentity $ encodeTag (tag there)
117− , 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
118169 }
119170
120− fromColumns2 f g HTheseTable {hhereTag, hhere, hthereTag, hthere} =
121− TheseTable
122− { here =
123− let
124− tag = decodeTag $ unHIdentity hhereTag
125− in
126− MaybeTable
127− { tag
128− , just = f $
129− runIdentity $
130− hunnullify (\a -> pure . unnullifier (isNonNull tag) a)
131− hhere
132− }
133− , there =
134− let
135− tag = decodeTag $ unHIdentity hthereTag
136− in
137− MaybeTable
138− { tag
139− , just = g $
140− runIdentity $
141− hunnullify (\a -> pure . unnullifier (isNonNull tag) a)
142− hthere
143− }
144− }
145−
146− {-# INLINABLE fromColumns2 #-}
147− {-# INLINABLE toColumns2 #-}
148−
149−
150−instance Table context a => Table1 (TheseTable a) where
151− type Columns1 (TheseTable a) = HTheseTable (Columns a)
152− 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+ }
153181
154− toColumns1 = toColumns2 toColumns
155− 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+ }
156226
157227
158−instance
159− ( Table context a, Table context b
160− , Labelable context, Nullifiable context
161− ) => Table context (TheseTable a b)
228+instance (OrdTable a, OrdTable b, context ~ Expr) =>
229+ OrdTable (TheseTable context a b)
162230 where
163− type Columns (TheseTable a b) =
164− HTheseTable (HLabel "Here" (Columns a)) (HLabel "There" (Columns b))
165− 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+ }
166237
167− toColumns =
168− toColumns2
169− (hlabel labeler . toColumns)
170− (hlabel labeler . toColumns)
171− fromColumns =
172− fromColumns2
173− (fromColumns . hunlabel unlabeler)
174− (fromColumns . hunlabel unlabeler)
175238
239+instance (ToExprs exprs1 a, ToExprs exprs2 b, x ~ TheseTable Expr exprs1 exprs2) =>
240+ ToExprs x (These a b)
176241
177−instance
178− ( Labelable from, Nullifiable from
179− , Labelable to, Nullifiable to
180− , Recontextualize from to a1 b1
181− , Recontextualize from to a2 b2
182− ) =>
183− Recontextualize from to (TheseTable a1 a2) (TheseTable b1 b2)
184242
185−
186−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
187247isThisTable a = hasHereTable a &&. not_ (hasThereTable a)
188248
189249
190−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
191254isThatTable a = not_ (hasHereTable a) &&. hasThereTable a
192255
193256
194−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
195261isThoseTable a = hasHereTable a &&. hasThereTable a
196262
197263
198−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
199268hasHereTable TheseTable {here} = isJustTable here
200269
201270
202−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
203275hasThereTable TheseTable {there} = isJustTable there
204276
205277
206−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
207282justHereTable = here
208283
209284
210−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
211289justThereTable = there
212290
213291
214−thisTable :: Table Expr 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
215304thisTable a = TheseTable (justTable a) nothingTable
216305
217306
218−thatTable :: Table Expr a => b -> TheseTable a b
307+-- | Construct a @TheseTable@. Corresponds to 'That'.
308+thatTable :: Table Expr a => b -> TheseTable Expr a b
219309thatTable b = TheseTable nothingTable (justTable b)
220310
221311
222−thoseTable :: a -> b -> TheseTable a b
312+-- | Construct a @TheseTable@. Corresponds to 'These'.
313+thoseTable :: a -> b -> TheseTable Expr a b
223314thoseTable a b = TheseTable (justTable a) (justTable b)
224315
225316
317+-- | Pattern match on a 'TheseTable'. Corresponds to 'these'.
226318theseTable :: Table Expr c
227− => (a -> c) -> (b -> c) -> (a -> b -> c) -> TheseTable a b -> c
319+ => (a -> c) -> (b -> c) -> (a -> b -> c) -> TheseTable Expr a b -> c
228320theseTable f g h TheseTable {here, there} =
229321 maybeTable
230322 (maybeTable undefined f here)
231323 (\b -> maybeTable (g b) (`h` b) here)
232324 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+6−6
@@ -11,16 +11,16 @@ where
1111import Prelude hiding ( undefined )
1212
1313-- rel8
14−import Rel8.Expr ( Expr, Col(..) )
14+import Rel8.Expr ( Expr )
1515import Rel8.Expr.Null ( snull, unsafeUnnullify )
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
2222undefined :: 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+549−140
@@ -1,231 +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.Table ( Table )
50−import Rel8.Table.Aggregate ( groupBy )
51−import Rel8.Table.Eq ( EqTable, (==:) )
52−import Rel8.Table.Maybe ( MaybeTable )
53−import Rel8.Table.These ( TheseTable, theseTable )
54−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 )
55118
56119-- semigroupoids
57120import Data.Functor.Apply ( Apply, liftF2 )
58−import Data.Functor.Bind ( Bind )
59−import qualified Data.Functor.Bind
60−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))
61185
62186
63−newtype Tabulation k a = Tabulation (k -> Query (Maybe k, a))
64− deriving stock Functor
187+instance Biprojectable Tabulation where
188+ biproject f g =
189+ bimap
190+ (fromColumns . apply f . toColumns)
191+ (fromColumns . apply g . toColumns)
65192
66193
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 (<*>))@
67209instance EqTable k => Apply (Tabulation k) where
68210 liftF2 = liftA2
69211
70212
213+-- | @pure = 'liftQuery' . pure@
71214instance EqTable k => Applicative (Tabulation k) where
72215 pure = liftQuery . pure
73216 liftA2 = liftM2
74217
75218
76219instance EqTable k => Bind (Tabulation k) where
77− 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)
78228
79229
80230instance EqTable k => Monad (Tabulation k) where
81− Tabulation as >>= f = Tabulation $ \i -> do
82− (mk, a) <- as i
83− case mk of
84− Nothing -> case f a of
85− Tabulation bs -> bs i
86− Just k -> case f a of
87− Tabulation bs -> do
88− (mk', b) <- bs k
89− case mk' of
90− Nothing -> pure (mk, b)
91− Just k' -> do
92− where_ $ k ==: k'
93− pure (mk', b)
94−
95−
96−runTabulation :: EqTable k => Tabulation k a -> Query (k, a)
97−runTabulation (Tabulation f) = do
98− (mk, a) <- f i
99− case mk of
100− Nothing -> do
101− -- Opaleye tries to be too clever optimising "WHERE FALSE" and generates
102− -- invalid SQL, so we use "WHERE NOT TRUE" instead
103− where_ $ not_ true
104− pure (i, a)
105− Just k -> pure (k, a)
106− where
107− i = undefined
231+ (>>=) = (>>-)
108232
109233
110−liftQuery :: Query a -> Tabulation k a
111−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
112244
113245
114−tabulate :: (a -> k) -> a -> Tabulation k a
115−tabulate key a = fromQuery $ pure (key a, a)
246+instance EqTable k => AlternativeTable (Tabulation k) where
247+ emptyTable = Tabulation $ const $ fmap (empty,) emptyTable
116248
117249
118−tabulateA :: (a -> Query k) -> a -> Tabulation k a
119−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 (<>))
120255
121256
122−fromQuery :: Query (k, a) -> Tabulation k a
123−fromQuery = Tabulation . const . fmap (first Just)
257+instance (EqTable k, Table Expr a, Semigroup a) => Monoid (Tabulation k a)
258+ where
259+ mempty = emptyTable
124260
125261
126−indexed :: Tabulation k a -> Tabulation k (k, a)
127−indexed (Tabulation query) = Tabulation $ \i ->
128− (\(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,)
129306
130307
131−ifilter :: (k -> a -> Expr Bool) -> Tabulation k a -> Tabulation k a
132−ifilter f tabulation = snd <$> do
133− 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`
134320
135321
136−prebind :: (a -> Tabulation k b) -> Query a -> Tabulation k b
137−prebind f as = Tabulation $ \k -> do
138− a <- as
139− case f a of
140− Tabulation query -> query k
141−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)
142330
143331
144−postbind :: (a -> Query b) -> Tabulation k a -> Tabulation k b
145−postbind f (Tabulation as) = Tabulation $ \i -> do
146− (k, a) <- as i
147− case f a of
148− bs -> do
149− b <- bs
150− pure (k, b)
151−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
152345
153346
154−lookup :: EqTable k => k -> Tabulation k a -> Query a
155−lookup key (Tabulation query) = do
156− (mk, a) <- query key
157− traverse_ (where_ . (key ==:)) mk
158− 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
159354
160355
161−align :: (EqTable k, Table Expr a, Table Expr b)
162− => 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)
163501align = alignWith id
164502
165503
166−alignWith :: (EqTable k, Table Expr a, Table Expr b)
167− => (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)
168509 -> Tabulation k a -> Tabulation k b -> Tabulation k c
169−alignWith f kas kbs = do
170− as <- toQuery kas
171− bs <- toQuery kbs
172− fromQuery $ do
173− tkab <- alignBy (\(l, _) (m, _) -> l ==: m) as bs
174− let
175− k' = theseTable fst fst (const fst) tkab
176− tab = bimap snd snd tkab
177− pure (k', f tab)
178−
179−
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.
180535leftAlign :: EqTable k
181− => Tabulation k a -> Tabulation k b -> Tabulation k (a, MaybeTable b)
536+ => Tabulation k a -> Tabulation k b -> Tabulation k (a, MaybeTable Expr b)
182537leftAlign = leftAlignWith (,)
183538
184539
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.
185548leftAlignWith :: EqTable k
186− => (a -> MaybeTable b -> c)
549+ => (a -> MaybeTable Expr b -> c)
187550 -> Tabulation k a -> Tabulation k b -> Tabulation k c
188−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)
189579
190580
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.
191588zip :: EqTable k
192589 => Tabulation k a -> Tabulation k b -> Tabulation k (a, b)
193590zip = zipWith (,)
194591
195592
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.
196600zipWith :: EqTable k
197601 => (a -> b -> c) -> Tabulation k a -> Tabulation k b -> Tabulation k c
198602zipWith = liftA2
199603
200604
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.
201615similarity :: EqTable k => Tabulation k a -> Tabulation k b -> Tabulation k a
202−similarity kas kbs = do
203− as <- toQuery kas
204− bs <- toQuery kbs
205− fromQuery $ as >>= withBy (\(k, _) (l, _) -> k ==: l) bs
206−
207−
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.
208629difference :: EqTable k => Tabulation k a -> Tabulation k b -> Tabulation k a
209−difference kas kbs = do
210− as <- toQuery kas
211− bs <- toQuery kbs
212− fromQuery $ as >>= withoutBy (\(k, _) (l, _) -> k ==: l) bs
213−
214−
215−aggregateTabulation :: EqTable k
216− => Tabulation k (Aggregate a) -> Tabulation k a
217−aggregateTabulation kas = do
218− as <- toQuery kas
219− fromQuery $ aggregate $ bitraverse1 groupBy id <$> as
220−
221−
222−optionalTabulation :: EqTable k
223− => Tabulation k a -> Tabulation k (MaybeTable a)
224−optionalTabulation as = Tabulation $ \k -> do
225− ma <- optional $ lookup k as
226− pure (Just k, ma)
630+difference a b = a <* absent b
227631
228632
229−toQuery :: Tabulation k a -> Tabulation k (Query (k, a))
230−toQuery (Tabulation as) = Tabulation $ \k ->
231− 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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src/Rel8/Type/Array1D.hsdeleted−136

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tests/Main.hs+341−193

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