src/Rel8/Schema/HTable/Identity.hs · rel8

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1{-# language DataKinds #-}

2{-# language GADTs #-}

3{-# language StandaloneKindSignatures #-}

4{-# language TypeFamilies #-}

6module Rel8.Schema.HTable.Identity

7 ( HIdentity(..)

8 )

9where

11-- base

12import Data.Kind ( Type )

13import Prelude

15-- rel8

16import Rel8.Schema.Dict ( Dict( Dict ) )

17import Rel8.Schema.HTable

18 ( HTable, HConstrainTable, HField

19 , hfield, htabulate, htraverse, hdicts, hspecs

20 )

21import qualified Rel8.Schema.Kind as K

22import Rel8.Schema.Spec ( Spec, KnownSpec, specSing )

25type HIdentity :: Spec -> K.HTable

26newtype HIdentity spec context = HIdentity

27 { unHIdentity :: context spec

28 }

31type HIdentityField :: Spec -> Spec -> Type

32data HIdentityField _spec spec where

33 HIdentityField :: HIdentityField spec spec

36instance KnownSpec spec => HTable (HIdentity spec) where

37 type HConstrainTable (HIdentity spec) c = c spec

38 type HField (HIdentity spec) = HIdentityField spec

40 hfield (HIdentity a) HIdentityField = a

41 htabulate f = HIdentity $ f HIdentityField

42 htraverse f (HIdentity a) = HIdentity <$> f a

43 hdicts = HIdentity Dict

44 hspecs = HIdentity specSing