src/Rel8/Schema/Spec.hs · rel8

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1{-# language DataKinds #-}

2{-# language FlexibleContexts #-}

3{-# language GADTs #-}

4{-# language StandaloneKindSignatures #-}

5{-# language UndecidableInstances #-}

7module Rel8.Schema.Spec

8 ( Spec( Spec )

9 , SSpec( SSpec, labels, info, nullity )

10 , KnownSpec( specSing )

11 )

12where

14-- base

15import Data.Kind ( Constraint, Type )

16import Prelude

18-- rel8

19import Rel8.Schema.Null ( Nullity, Sql, Unnullify, nullable )

20import Rel8.Type ( DBType, typeInformation )

21import Rel8.Type.Information ( TypeInformation )

24type Spec :: Type

25newtype Spec = Spec Type

28type SSpec :: Spec -> Type

29data SSpec spec where

30 SSpec ::

31 { labels :: [String]

32 , info :: TypeInformation (Unnullify a)

33 , nullity :: Nullity a

34 }

35 -> SSpec ('Spec a)

38type KnownSpec :: Spec -> Constraint

39class KnownSpec spec where

40 specSing :: SSpec spec

43instance Sql DBType a => KnownSpec ('Spec a) where

44 specSing = SSpec

45 { labels = []

46 , info = typeInformation

47 , nullity = nullable

48 }