src/Rel8/Generic/Map.hs · rel8

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1{-# language DataKinds #-}

2{-# language StandaloneKindSignatures #-}

3{-# language TypeFamilies #-}

4{-# language TypeOperators #-}

6module Rel8.Generic.Map

7 ( GMap

8 )

9where

11-- base

12import Data.Kind ( Type )

13import GHC.Generics

14 ( (:+:), (:*:), K1, M1, U1, V1

15 )

16import Prelude ()

18-- rel8

19import Rel8.FCF ( Eval, Exp )

22type GMap :: (Type -> Exp Type) -> (Type -> Type) -> Type -> Type

23type family GMap f rep where

24 GMap f (M1 i c rep) = M1 i c (GMap f rep)

25 GMap _ V1 = V1

26 GMap f (rep1 :+: rep2) = GMap f rep1 :+: GMap f rep2

27 GMap _ U1 = U1

28 GMap f (rep1 :*: rep2) = GMap f rep1 :*: GMap f rep2

29 GMap f (K1 i a) = K1 i (Eval (f a))