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

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1{-# language DataKinds #-}

2{-# language DeriveAnyClass #-}

3{-# language DeriveGeneric #-}

4{-# language DerivingStrategies #-}

5{-# language FlexibleInstances #-}

6{-# language StandaloneKindSignatures #-}

7{-# language UndecidableInstances #-}

8{-# language UndecidableSuperClasses #-}

10module Rel8.Schema.HTable.Either

11 ( HEitherTable(..)

12 , HEitherNullifiable

13 )

14where

16-- base

17import Data.Kind ( Constraint )

18import GHC.Generics ( Generic )

19import Prelude ()

21-- rel8

22import Rel8.Kind.Necessity ( Necessity( Required ) )

23import Rel8.Schema.Context.Nullify ( HNullifiable, HConstrainTag )

24import Rel8.Schema.HTable ( HTable )

25import Rel8.Schema.HTable.Identity ( HIdentity(..) )

26import Rel8.Schema.HTable.Nullify ( HNullify )

27import qualified Rel8.Schema.Kind as K

28import Rel8.Schema.Spec ( Spec( Spec ) )

29import Rel8.Type.Tag ( EitherTag )

32type HEitherTable :: K.HTable -> K.HTable -> K.HTable

33data HEitherTable left right context = HEitherTable

34 { htag :: HIdentity ('Spec '["isRight"] 'Required EitherTag) context

35 , hleft :: HNullify left context

36 , hright :: HNullify right context

37 }

38 deriving stock Generic

39 deriving anyclass HTable

42type HEitherNullifiable :: K.HContext -> Constraint

43class (HNullifiable context, HConstrainTag context EitherTag) => HEitherNullifiable context

44instance (HNullifiable context, HConstrainTag context EitherTag) => HEitherNullifiable context