{-# LANGUAGE AllowAmbiguousTypes #-}
{-# LANGUAGE DataKinds #-}
module Symantic.CurryN where

import Data.Function (($), (.))

import Symantic.ADT (Tuples)

-- * Class 'CurryN'
-- | Produce and consume 'Tuples'.
-- Not actually useful for the Generic side of this module,
-- but related through the use of 'Tuples'.
class CurryN args where
  -- Like 'curry' but for an arbitrary number of nested 2-tuples.
  curryN :: (Tuples args -> res) -> args-..->res
  -- Like 'uncurry' but for an arbitrary number of nested 2-tuples.
  uncurryN :: (args-..->res) -> Tuples args -> res
  -- Like 'fmap' on @('->')@ but for an arbitrary number of arguments.
  mapresultN :: (a->b) -> (args-..->a) -> args-..->b
instance CurryN '[a] where
  curryN :: (Tuples '[a] -> res) -> '[a] -..-> res
curryN = (Tuples '[a] -> res) -> '[a] -..-> res
forall a b. (a -> b) -> a -> b
($)
  uncurryN :: ('[a] -..-> res) -> Tuples '[a] -> res
uncurryN = ('[a] -..-> res) -> Tuples '[a] -> res
forall a b. (a -> b) -> a -> b
($)
  mapresultN :: (a -> b) -> ('[a] -..-> a) -> '[a] -..-> b
mapresultN = (a -> b) -> ('[a] -..-> a) -> '[a] -..-> b
forall b c a. (b -> c) -> (a -> b) -> a -> c
(.)
instance CurryN (b ': as) => CurryN (a ': b ': as) where
  curryN :: (Tuples (a : b : as) -> res) -> (a : b : as) -..-> res
curryN Tuples (a : b : as) -> res
f a
x = (Tuples (b : as) -> res) -> (b : as) -..-> res
forall (args :: [*]) res.
CurryN args =>
(Tuples args -> res) -> args -..-> res
curryN @(b ': as) (\Tuples (b : as)
xs -> Tuples (a : b : as) -> res
f (a
x, Tuples (b : as)
xs))
  uncurryN :: ((a : b : as) -..-> res) -> Tuples (a : b : as) -> res
uncurryN (a : b : as) -..-> res
f (x, xs) = ((b : as) -..-> res) -> Tuples (b : as) -> res
forall (args :: [*]) res.
CurryN args =>
(args -..-> res) -> Tuples args -> res
uncurryN @(b ': as) ((a : b : as) -..-> res
a -> b -> as -..-> res
f a
x) Tuples (b : as)
xs
  mapresultN :: (a -> b) -> ((a : b : as) -..-> a) -> (a : b : as) -..-> b
mapresultN a -> b
f (a : b : as) -..-> a
as2r = (a -> b) -> ((b : as) -..-> a) -> (b : as) -..-> b
forall (args :: [*]) a b.
CurryN args =>
(a -> b) -> (args -..-> a) -> args -..-> b
mapresultN @(b ': as) a -> b
f ((b -> as -..-> a) -> b -> as -..-> b)
-> (a -> b -> as -..-> a) -> a -> b -> as -..-> b
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (a : b : as) -..-> a
a -> b -> as -..-> a
as2r

-- ** Type family ('-..->')
type family (args :: [*]) -..-> (r :: *) :: * where
  '[]        -..-> r = r
  (a : args) -..-> r = a -> args -..-> r
-- ** Type family 'Args'
type family Args (f :: *) :: [*] where
  Args (a -> r) = a : Args r
  Args r = '[]
-- ** Type family 'Result'
type family Result (as :: *) :: * where
  Result (a -> r) = Result r
  Result r = r