git.iko.soy/rel8
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rel8/src/Rel8/Column.hs
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1{-# language DataKinds #-}
2{-# language FlexibleContexts #-}
3{-# language LambdaCase #-}
4{-# language MultiParamTypeClasses #-}
5{-# language StandaloneKindSignatures #-}
6{-# language TypeFamilies #-}
8module Rel8.Column
9 ( Column, AColumn(..)
10 , TColumn
11 )
12where
14-- base
15import Data.Kind ( Type )
16import Prelude
18-- rel8
19import Rel8.Aggregate ( Aggregate, Col( A ) )
20import Rel8.Expr ( Expr, Col( E ) )
21import Rel8.FCF ( Eval, Exp )
22import Rel8.Kind.Context ( SContext(..), Reifiable( contextSing ) )
23import Rel8.Schema.HTable.Identity ( HIdentity( HIdentity ) )
24import qualified Rel8.Schema.Kind as K
25import Rel8.Schema.Name ( Name(..), Col( N ) )
26import Rel8.Schema.Null ( Sql )
27import Rel8.Schema.Reify ( Reify, Col(..) )
28import Rel8.Schema.Result ( Col( R ), Result )
29import Rel8.Schema.Spec ( Spec( Spec ) )
30import Rel8.Table
31 ( Table, Columns, Context, fromColumns, toColumns
32 , Unreify, reify, unreify
33 )
34import Rel8.Table.Recontextualize ( Recontextualize )
35import Rel8.Type ( DBType )
38type Column :: K.Context -> Type -> Type
39type family Column context a where
40 Column (Reify context) a = AColumn context a
41 Column Aggregate a = Aggregate a
42 Column Expr a = Expr a
43 Column Name a = Name a
44 Column Result a = a
47type AColumn :: K.Context -> Type -> Type
48newtype AColumn context a = AColumn (Column context a)
51instance (Reifiable context, Sql DBType a) =>
52 Table (Reify context) (AColumn context a)
53 where
54 type Context (AColumn context a) = Reify context
55 type Columns (AColumn context a) = HIdentity ('Spec '[] a)
56 type Unreify (AColumn context a) = Column context a
58 fromColumns (HIdentity (Reify a)) = sfromColumn contextSing a
59 toColumns = HIdentity . Reify . stoColumn contextSing
60 reify _ = AColumn
61 unreify _ (AColumn a) = a
64instance
65 ( Reifiable context, Reifiable context'
66 , Sql DBType a
67 ) =>
68 Recontextualize
69 (Reify context)
70 (Reify context')
71 (AColumn context a)
72 (AColumn context' a)
75sfromColumn :: ()
76 => SContext context
77 -> Col context ('Spec labels a)
78 -> AColumn context a
79sfromColumn = \case
80 SAggregate -> \(A a) -> AColumn a
81 SExpr -> \(E a) -> AColumn a
82 SName -> \(N a) -> AColumn a
83 SResult -> \(R a) -> AColumn a
84 SReify context -> \(Reify a) -> AColumn (sfromColumn context a)
87stoColumn :: ()
88 => SContext context
89 -> AColumn context a
90 -> Col context ('Spec labels a)
91stoColumn = \case
92 SAggregate -> \(AColumn a) -> A a
93 SExpr -> \(AColumn a) -> E a
94 SName -> \(AColumn a) -> N a
95 SResult -> \(AColumn a) -> R a
96 SReify context -> \(AColumn a) -> Reify (stoColumn context a)
99data TColumn :: K.Context -> Type -> Exp Type
100type instance Eval (TColumn f a) = Column f a