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

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1{-# language DataKinds #-}

2{-# language DeriveAnyClass #-}

3{-# language DeriveGeneric #-}

4{-# language DerivingStrategies #-}

5{-# language StandaloneKindSignatures #-}

7module Rel8.Schema.HTable.Maybe

8 ( HMaybeTable(..)

9 )

10where

12-- base

13import GHC.Generics ( Generic )

14import Prelude

16-- rel8

17import Rel8.Schema.HTable ( HTable )

18import Rel8.Schema.HTable.Identity ( HIdentity(..) )

19import Rel8.Schema.HTable.Label ( HLabel )

20import Rel8.Schema.HTable.Nullify ( HNullify )

21import qualified Rel8.Schema.Kind as K

22import Rel8.Schema.Spec ( Spec( Spec ) )

23import Rel8.Type.Tag ( MaybeTag )

26type HMaybeTable :: K.HTable -> K.HTable

27data HMaybeTable table context = HMaybeTable

28 { htag :: HIdentity ('Spec '["isJust"] (Maybe MaybeTag)) context

29 , hjust :: HLabel "Just" (HNullify table) context

30 }

31 deriving stock Generic

32 deriving anyclass HTable