src/Rel8/Column/These.hs · rel8

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1{-# language DataKinds #-}

2{-# language StandaloneKindSignatures #-}

3{-# language TypeFamilyDependencies #-}

5module Rel8.Column.These

6 ( HThese

7 )

8where

10-- base

11import Data.Kind ( Type )

12import Prelude ()

14-- rel8

15import qualified Rel8.Schema.Kind as K

16import Rel8.Schema.Result ( Result )

17import Rel8.Table.These ( TheseTable )

19-- these

20import Data.These ( These )

23-- | Nest an 'These' value within a 'Rel8able'. @HThese f a b@ will produce a

24-- 'TheseTable' @a b@ in the 'Expr' context, and a 'These' @a b@ in the

25-- 'Result' context.

26type HThese :: K.Context -> Type -> Type -> Type

27type family HThese context = these | these -> context where

28 HThese Result = These

29 HThese context = TheseTable context