{-# OPTIONS_HADDOCK hide #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE InstanceSigs #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE UndecidableInstances #-}
module Data.Generics.Internal.GenericN
( Param (..)
, Rec (Rec, unRec)
, GenericN (..)
) where
import Data.Kind
import GHC.Generics
import GHC.TypeLits
import Data.Coerce
data family Param :: Nat -> j -> k
newtype instance Param n (a :: Type)
= StarParam { Param n a -> a
getStarParam :: a}
type family Indexed (t :: k) (i :: Nat) :: k where
Indexed (t a) i = Indexed t (i + 1) (Param i a)
Indexed t _ = t
newtype Rec (p :: Type) a x = Rec { Rec p a x -> K1 R a x
unRec :: K1 R a x }
class
( Coercible (Rep a) (RepN a)
, Generic a
) => GenericN (a :: Type) where
type family RepN (a :: Type) :: Type -> Type
type instance RepN a = Rep (Indexed a 0)
toN :: RepN a x -> a
fromN :: a -> RepN a x
instance
( Coercible (Rep a) (RepN a)
, Generic a
) => GenericN a where
toN :: forall x. RepN a x -> a
toN :: RepN a x -> a
toN = (Rep a x -> a) -> Rep (Indexed a 0) x -> a
coerce (Rep a x -> a
forall a x. Generic a => Rep a x -> a
to :: Rep a x -> a)
{-# INLINE toN #-}
fromN :: forall x. a -> RepN a x
fromN :: a -> RepN a x
fromN = (a -> Rep a x) -> a -> Rep (Indexed a 0) x
coerce (a -> Rep a x
forall a x. Generic a => a -> Rep a x
from :: a -> Rep a x)
{-# INLINE fromN #-}