src/Rel8/FCF.hs · rel8

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rel8/src/Rel8/FCF.hs

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1{-# language DataKinds #-}

2{-# language PolyKinds #-}

3{-# language StandaloneKindSignatures #-}

4{-# language TypeFamilies #-}

6module Rel8.FCF

7 ( Exp, Eval

8 , Compose

9 )

10where

12-- base

13import Data.Kind ( Type )

14import Prelude ()

17type Exp :: Type -> Type

18type Exp e = e -> Type

21type Eval :: Exp e -> e

22type family Eval a

25data Compose :: (Type -> Type) -> (Type -> Exp Type) -> Type -> Exp Type

26type instance Eval (Compose f g a) = f (Eval (g a))