{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE ScopedTypeVariables, InstanceSigs #-}
{-# LANGUAGE DataKinds, KindSignatures, TypeOperators #-}
{-# LANGUAGE GADTs, TypeFamilies #-}
{-# LANGUAGE MultiParamTypeClasses, FlexibleContexts, FlexibleInstances,
	UndecidableInstances #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# OPTIONS_GHC -Wall -fno-warn-tabs -fplugin=Plugin.TypeCheck.Nat.Simple #-}

module Data.List.Range.RangeR (
	-- ** Type
	RangeR(..),
	-- ** PushR
	PushR, (.:++),
	-- ** AddR
	AddR, (+++),
	-- ** LoosenRMin and LoosenRMax
	-- *** loosenR
	loosenR,
	-- *** loosenRMin
	LoosenRMin, loosenRMin,
	-- *** loosenRMax
	LoosenRMax, loosenRMax,
	-- ** Unfoldl
	-- *** class
	Unfoldl,
	-- *** unfoldlRange
	-- **** without monad
	unfoldlRange, unfoldlRangeWithBase, unfoldlRangeWithBaseWithS,
	-- **** with monad
	unfoldlMRange, unfoldlMRangeWithBase,
	-- *** unfoldlRangeMaybe
	-- **** without monad
	unfoldlRangeMaybe, unfoldlRangeMaybeWithBase,
	-- **** with monad
	unfoldlMRangeMaybe, unfoldlMRangeMaybeWithBase,
	-- ** ZipR
	ZipR, zipR, zipWithR, zipWithMR ) where

import GHC.TypeNats (Nat, type (+), type (-), type (<=))
import GHC.Exts
import Control.Arrow (first, second, (***), (&&&))
import Control.Monad.Identity (Identity(..))
import Control.Monad.State (StateR(..))
import Data.Foldable
import Data.Bool (bool)
import Data.Maybe (isJust, fromMaybe)
-- import Data.String

---------------------------------------------------------------------------

-- * TYPE
--	+ RANGE RIGHT
--	+ INSTANCE FUNCTOR
--	+ INSTANCE FOLDABLE
-- * PUSH
-- * ADD
-- * LOOSEN
--	+ LOOSEN RIGHT
--	+ LOOSEN RIGHT MIN
--	+ LOOSEN RIGHT MAX
-- * UNFOLDL
--	+ CLASS
--	+ INSTANCE
--	+ UNFOLDL RANGE
--	+ UNFOLDL RANGE MAYBE
-- * ZIP
--	+ CLASS AND INSTANCE
--	+ FUNCTION

---------------------------------------------------------------------------
-- TYPE
---------------------------------------------------------------------------

-- RANGE RIGHT

data RangeR :: Nat -> Nat -> * -> * where
	NilR :: 0 <= m => RangeR 0 m a
	(:++) :: 1 <= m => RangeR 0 (m - 1) a -> a -> RangeR 0 m a
	(:+) :: (1 <= n, 1 <= m) =>
		RangeR (n - 1) (m - 1) a -> a -> RangeR n m a

{-^

@RangeR n m a@ is a list of type @a@ values whose element number is
at minimum @n@, and at maximum @m@.
You can push and pop an element from right.

>>> :set -XDataKinds
>>> sampleRangeR = NilR :++ 'h' :++ 'e' :+ 'l' :+ 'l' :+ 'o' :: RangeR 3 8 Char

-}

infixl 6 :+, :++

deriving instance Show a => Show (RangeR n m a)

-- INSTANCE FUNCTOR

instance Functor (RangeR 0 0) where _ `fmap` NilR = NilR

instance {-# OVERLAPPABLE #-}
	Functor (RangeR 0 (m - 1)) => Functor (RangeR 0 m) where
	fmap f = \case NilR -> NilR; xs :++ x -> (f <$> xs) :++ f x

instance {-# OVERLAPPABLE #-}
	(1 <= n, Functor (RangeR (n - 1) (m - 1))) => Functor (RangeR n m) where
	f `fmap` (xs :+ x) = (f <$> xs) :+ f x

-- INSTANCE FOLDABLE

instance Foldable (RangeR 0 0) where foldr _ z NilR = z

instance {-# OVERLAPPABLE #-}
	Foldable (RangeR 0 (m - 1)) => Foldable (RangeR 0 m) where
	foldr (-<) z = \case NilR -> z; xs :++ x -> foldr (-<) (x -< z) xs

instance {-# OVERLAPPABLE #-} (1 <= n, Foldable (RangeR (n - 1) (m - 1))) =>
	Foldable (RangeR n m) where
	foldr (-<) z (xs :+ x) = foldr (-<) (x -< z) xs

instance Applicative (RangeR 0 0) where pure _ = NilR; _ <*> _ = NilR

instance {-# OVERLAPPABLE #-} (1 <= n, Functor (RangeR n n), Applicative (RangeR (n - 1) (n - 1)), Unfoldl 0 n n) => Applicative (RangeR n n) where
	pure = unfoldlRange (const True) (\x -> (x, x))
	fs :+ f <*> xs :+ x = (fs <*> xs) :+ f x

instance {-# OVERLAPPABLE #-} (Functor (RangeR 0 m), Applicative (RangeR 0 (m - 1)), Unfoldl 0 0 m) => Applicative (RangeR 0 m) where
	pure = unfoldlRange (const True) (\x -> (x, x))
	NilR <*> _ = NilR
	_ <*> NilR = NilR
	fs :++ f <*> xs :++ x = (fs <*> xs) :++ f x

instance {-# OVERLAPPABLE #-} (1 <= n, Functor (RangeR n m), Applicative (RangeR (n - 1) (m - 1)), Unfoldl 0 n m) => Applicative (RangeR n m) where
	pure = unfoldlRange (const True) (\x -> (x, x))
	fs :+ f <*> xs :+ x = (fs <*> xs) :+ f x

instance Applicative (RangeR 0 0) => Monad (RangeR 0 0) where NilR >>= _ = NilR


instance {-# OVERLAPPABLE #-} (1 <= n, Applicative (RangeR n n), Monad (RangeR (n - 1) (n - 1))) => Monad (RangeR n n) where
	xs :+ x >>= f = (xs >>= \z -> case f z of zs :+ _ -> zs) :+ y
		where _ :+ y = f x

-- INSTANCE ISSTRING

instance Unfoldl 0 n m => IsString (RangeR n m Char) where
	fromString s = fromMaybe (error $ "The string " ++ show s ++ " is not within range.")
		. unfoldlRangeMaybe (\case "" -> Nothing; c : cs -> Just (cs, c)) $ reverse s

instance (Foldable (RangeR n m), Unfoldl 0 n m) => IsList (RangeR n m a) where
	type Item (RangeR n m a) = a
	fromList lst = fromMaybe (error $ "The list is not within range.")
		. unfoldlRangeMaybe (\case [] -> Nothing; x : xs -> Just (xs, x)) $ reverse lst
	toList = Data.Foldable.toList

---------------------------------------------------------------------------
-- PUSH
---------------------------------------------------------------------------

infixl 5 .:++

class PushR n m where
	(.:++) :: RangeR n m a -> a -> RangeR n (m + 1) a

	{-^

	To push an optional element.

	>>> :set -XDataKinds
	>>> samplePushR = NilR :++ 'h' :+ 'e' :+ 'l' :+ 'l' :: RangeR 3 7 Char
	>>> samplePushR .:++ 'o'
	((((NilR :++ 'h') :++ 'e') :+ 'l') :+ 'l') :+ 'o'
	>>> :type samplePushR .:++ 'o'
	samplePushR .:++ 'o' :: RangeR 3 8 Char

	-}

instance PushR 0 m where
	(.:++) = \case NilR -> (NilR :++); xs@(_ :++ _) -> (xs :++)

instance {-# OVERLAPPABLE #-} (1 <= n, PushR (n - 1) (m - 1)) => PushR n m where
	xs :+ x .:++ y = (xs .:++ x) :+ y

---------------------------------------------------------------------------
-- ADD
---------------------------------------------------------------------------

infixl 5 +++

class AddR n m v w where
	(+++) :: RangeR n m a -> RangeR v w a -> RangeR (n + v) (m + w) a

	{-^

	To concatenate two lists whose types are @RangeR n m a@ and @RangeR v w a@.

	>>> :set -XDataKinds
	>>> sampleRangeR1 = NilR :++ 'f' :+ 'o' :+ 'o' :: RangeR 2 5 Char
	>>> sampleRangeR2 = NilR :++ 'b' :++ 'a' :+ 'r' :: RangeR 1 6 Char
	>>> sampleRangeR1 +++ sampleRangeR2
	(((((NilR :++ 'f') :++ 'o') :++ 'o') :+ 'b') :+ 'a') :+ 'r'
	>>> :type sampleRangeR1 +++ sampleRangeR2
	sampleRangeR1 +++ sampleRangeR2 :: RangeR 3 11 Char

	-}

instance AddR n m 0 0 where xs +++ NilR = xs

instance {-# OVERLAPPABLE #-}
	(PushR n (m + w - 1), AddR n m 0 (w - 1), LoosenRMax n m (m + w)) =>
	AddR n m 0 w where
	(+++) :: forall a . RangeR n m a -> RangeR 0 w a -> RangeR n (m + w) a
	(+++) xs = \case
		NilR -> loosenRMax xs
		ys :++ y -> (xs +++ ys :: RangeR n (m + w - 1) a) .:++ y

instance {-# OVERLAPPABLE #-}
	(1 <= v, AddR n m (v - 1) (w - 1)) => AddR n m v w where
	xs +++ ys :+ y = (xs +++ ys) :+ y

---------------------------------------------------------------------------
-- LOOSEN
---------------------------------------------------------------------------

-- LOOSEN RIGHT

loosenR :: (LoosenRMin n m v, LoosenRMax v m w) => RangeR n m a -> RangeR v w a
loosenR = loosenRMax . loosenRMin

{-^

To loosen a range of element number.

>>> :set -XDataKinds
>>> sampleLoosenR = NilR :++ 'h' :+ 'e' :+ 'l' :+ 'l' :+ 'o' :: RangeR 4 6 Char
>>> loosenR sampleLoosenR :: RangeR 2 8 Char
((((NilR :++ 'h') :++ 'e') :++ 'l') :+ 'l') :+ 'o'

-}

-- LOOSEN RIGHT MIN

class LoosenRMin n m v where
	loosenRMin :: RangeR n m a -> RangeR v m a

	{-^

	To loosen a lower bound of element number.

	>>> :set -XDataKinds -fno-warn-tabs
	>>> :{
		sampleLoosenRMin :: RangeR 4 6 Char
		sampleLoosenRMin = NilR :++ 'h' :+ 'e' :+ 'l' :+ 'l' :+ 'o'
	:}

	>>> loosenRMin sampleLoosenRMin :: RangeR 2 6 Char
	((((NilR :++ 'h') :++ 'e') :++ 'l') :+ 'l') :+ 'o'

	-}

instance LoosenRMin 0 m 0 where
	loosenRMin = \case NilR -> NilR; xs@(_ :++ _) -> xs

instance {-# OVERLAPPABLE #-}
	(1 <= n, LoosenRMin (n - 1) (m - 1) 0) => LoosenRMin n m 0 where
	loosenRMin (xs :+ x) = loosenRMin xs :++ x

instance {-# OVERLAPPABLE #-}
	(1 <= n, LoosenRMin (n - 1) (m - 1) (v - 1)) => LoosenRMin n m v where
	loosenRMin (xs :+ x) = loosenRMin xs :+ x

-- LOOSEN RIGHT MAX

class LoosenRMax n m w where
	loosenRMax :: RangeR n m a -> RangeR n w a

	{-^

	To loosen an upper bound of element number.

	>>> :set -XDataKinds -fno-warn-tabs
	>>> :{
		sampleLoosenRMax :: RangeR 4 6 Char
		sampleLoosenRMax = NilR :++ 'h' :+ 'e' :+ 'l' :+ 'l' :+ 'o'
	:}

	>>> loosenRMax sampleLoosenRMax :: RangeR 4 8 Char
	((((NilR :++ 'h') :+ 'e') :+ 'l') :+ 'l') :+ 'o'

	-}

instance LoosenRMax 0 0 m where loosenRMax NilR = NilR

instance {-# OVERLAPPABLE #-}
	LoosenRMax 0 (m - 1) (w - 1) => LoosenRMax 0 m w where
	loosenRMax = \case NilR -> NilR; xs :++ x -> loosenRMax xs :++ x

instance {-# OVERLAPPABLE #-}
	(1 <= n, LoosenRMax (n - 1) (m - 1) (w - 1)) => LoosenRMax n m w where
	loosenRMax (xs :+ x) = loosenRMax xs :+ x

---------------------------------------------------------------------------
-- UNFOLDL
---------------------------------------------------------------------------

-- CLASS

class Unfoldl n v w where
	unfoldlMRangeWithBase :: Monad m =>
		m Bool -> m a -> RangeR n w a -> m (RangeR v w a)

	{-^

	It is like @unfoldlMRange@. But it has already prepared values.

	>>> :set -XDataKinds
	>>> :module + Data.IORef
	>>> r <- newIORef 1
	>>> count = readIORef r >>= \n -> n * 3 <$ writeIORef r (n + 1)
	>>> xs = NilR :++ 123 :+ 456 :: RangeR 1 5 Integer
	>>> :{
		unfoldlMRangeWithBase ((< 3) <$> readIORef r) count xs
			:: IO (RangeR 3 5 Integer)
	:}
	(((NilR :++ 6) :+ 3) :+ 123) :+ 456

	-}

	unfoldlMRangeMaybeWithBase :: Monad m =>
		m Bool -> m a -> RangeR n w a -> m (Maybe (RangeR v w a))

	{-^

	It is like @unfoldrMRangeMaybe@. But it has already prepared values.

	>>> :set -XDataKinds
	>>> :module + Data.IORef
	>>> r <- newIORef 1
	>>> check = (< 3) <$> readIORef r
	>>> count = readIORef r >>= \n -> n * 3 <$ writeIORef r (n + 1)
	>>> xs = NilR :++ 123 :+ 456 :: RangeR 1 5 Integer
	>>> :{
		unfoldlMRangeMaybeWithBase check count xs
			:: IO (Maybe (RangeR 3 5 Integer))
	:}
	Just ((((NilR :++ 6) :+ 3) :+ 123) :+ 456)

	-}

-- INSTANCE

instance Unfoldl 0 0 0 where
	unfoldlMRangeWithBase _ _ NilR = pure NilR
	unfoldlMRangeMaybeWithBase p _ NilR = bool (Just NilR) Nothing <$> p

instance {-# OVERLAPPABLE #-} Unfoldl 0 0 (w - 1) => Unfoldl 0 0 w where
	unfoldlMRangeWithBase p f = \case
		NilR -> (p >>=) . bool (pure NilR) $ f >>= \x ->
			(:++ x) <$> unfoldlMRangeWithBase p f NilR
		xs :++ x -> (:++ x) <$> unfoldlMRangeWithBase p f xs

	unfoldlMRangeMaybeWithBase p f = \case
		NilR -> (p >>=) . bool (pure $ Just NilR) $ f >>= \x ->
			((:++ x) <$>) <$> unfoldlMRangeMaybeWithBase p f NilR
		xs :++ x -> ((:++ x) <$>) <$> unfoldlMRangeMaybeWithBase p f xs

instance {-# OVERLAPPABLE #-} Unfoldl 0 (v - 1) (w - 1) => Unfoldl 0 v w where
	unfoldlMRangeWithBase p f = \case
		NilR -> f >>= \x -> (:+ x) <$> unfoldlMRangeWithBase p f NilR
		xs :++ x -> (:+ x) <$> unfoldlMRangeWithBase p f xs

	unfoldlMRangeMaybeWithBase p f = \case
		NilR -> (p >>=) . bool (pure Nothing) $ f >>= \x ->
			((:+ x) <$>) <$> unfoldlMRangeMaybeWithBase p f NilR
		xs :++ x -> ((:+ x) <$>) <$> unfoldlMRangeMaybeWithBase p f xs

instance {-# OVERLAPPABLE #-}
	(1 <= n, Unfoldl (n - 1) (v - 1) (w - 1)) => Unfoldl n v w where
	unfoldlMRangeWithBase p f (xs :+ x) =
		(:+ x) <$> unfoldlMRangeWithBase p f xs

	unfoldlMRangeMaybeWithBase p f (xs :+ x) =
		((:+ x) <$>) <$> unfoldlMRangeMaybeWithBase p f xs

-- UNFOLDL RANGE

unfoldlRange :: Unfoldl 0 v w =>
	(s -> Bool) -> (s -> (s, a)) -> s -> RangeR v w a
unfoldlRange p f s = unfoldlRangeWithBase p f s NilR

{-^

To eveluate a function to construct a list.
The function recieve a state and return an element and a new state.
The first argument is a predication which is evaluated when an element number is
greater than a minimum and not greater than a maximum.

>>> :set -XDataKinds
>>> unfoldlRange (< 2) (\n -> (n + 1, n * 3)) 1 :: RangeR 3 5 Int
((NilR :+ 9) :+ 6) :+ 3

>>> unfoldlRange (< 5) (\n -> (n + 1, n * 3)) 1 :: RangeR 3 5 Int
(((NilR :++ 12) :+ 9) :+ 6) :+ 3

>>> unfoldlRange (< 10) (\n -> (n + 1, n * 3)) 1 :: RangeR 3 5 Int
((((NilR :++ 15) :++ 12) :+ 9) :+ 6) :+ 3

-}

unfoldlRangeWithBase :: Unfoldl n v w =>
	(s -> Bool) -> (s -> (s, a)) -> s -> RangeR n w a -> RangeR v w a
unfoldlRangeWithBase p f = (snd .) . unfoldlRangeWithBaseWithS p f

{-^

It is like @unfoldlRange@. But it has already prepared values.

>>> :set -XDataKinds
>>> xs = NilR :++ 123 :+ 456 :: RangeR 1 5 Integer
>>> unfoldlRangeWithBase (< 3) (\n -> (n + 1, n * 3)) 1 xs :: RangeR 3 5 Integer
(((NilR :++ 6) :+ 3) :+ 123) :+ 456

-}

unfoldlRangeWithBaseWithS :: Unfoldl n v w =>
	(s -> Bool) -> (s -> (s, a)) -> s -> RangeR n w a -> (s, RangeR v w a)
unfoldlRangeWithBaseWithS p f =
	flip $ runStateR . unfoldlMRangeWithBase (StateR $ id &&& p) (StateR f)

{-^

It is like @unfoldlRangeWithBase@.
But it return not only a list but also a state value.

>>> :set -XDataKinds -fno-warn-tabs
>>> xs = NilR :++ 123 :+ 456 :: RangeR 1 5 Integer
>>> :{
	unfoldlRangeWithBaseWithS (< 3) (\n -> (n + 1, n * 3)) 1 xs
		:: (Integer, RangeR 3 5 Integer)
:}
(3,(((NilR :++ 6) :+ 3) :+ 123) :+ 456)

-}

unfoldlMRange :: (Unfoldl 0 v w, Monad m) => m Bool -> m a -> m (RangeR v w a)
unfoldlMRange p f = unfoldlMRangeWithBase p f NilR

{-^

It is like @unfoldlRange@. But it use a monad instead of a function.

>>> :set -XDataKinds
>>> :module + Data.IORef
>>> r <- newIORef 1
>>> count = readIORef r >>= \n -> n * 3 <$ writeIORef r (n + 1)
>>> unfoldlMRange ((< 5) <$> readIORef r) count :: IO (RangeR 3 5 Integer)
(((NilR :++ 12) :+ 9) :+ 6) :+ 3

-}

-- UNFOLDL RANGE MAYBE

unfoldlRangeMaybe ::
	Unfoldl 0 v w => (s -> Maybe (s, a)) -> s -> Maybe (RangeR v w a)
unfoldlRangeMaybe f s = unfoldlRangeMaybeWithBase f s NilR

{-^

To evaluate a function to construct a list.
The function recieves a state and
return a nothing value or an element and a new state.
If the number of created elements is
less than a minimum number of list elements or
greater than a maximum number, then return @Nothing@.

>>> :set -XDataKinds
>>> count n0 n = if n < n0 then Just (n + 1, n * 3) else Nothing
>>> unfoldlRangeMaybe (count 2) 1 :: Maybe (RangeR 3 5 Int)
Nothing

>>> unfoldlRangeMaybe (count 5) 1 :: Maybe (RangeR 3 5 Int)
Just ((((NilR :++ 12) :+ 9) :+ 6) :+ 3)

>>> unfoldlRangeMaybe (count 10) 1 :: Maybe (RangeR 3 5 Int)
Nothing

-}

unfoldlRangeMaybeWithBase :: Unfoldl n v w =>
	(s -> Maybe (s, a)) -> s -> RangeR n w a -> Maybe (RangeR v w a)
unfoldlRangeMaybeWithBase f s xs =
	snd $ unfoldlRangeMaybeWithBaseGen (id &&& isJust)
		(maybe (error "never occur") (f `first`)) xs (f s)

{-^

It is like @unfoldlRangeMaybe@. But it has already prepared values.

>>> :set -XDataKinds
>>> count n = if n < 3 then Just (n + 1, n * 3) else Nothing
>>> xs = NilR :++ 123 :+ 456 :: RangeR 1 5 Int
>>> unfoldlRangeMaybeWithBase count 1 xs :: Maybe (RangeR 3 5 Int)
Just ((((NilR :++ 6) :+ 3) :+ 123) :+ 456)

-}

type St s a r = Maybe (s, a) -> (Maybe (s, a), r)

unfoldlRangeMaybeWithBaseGen :: Unfoldl n v w =>
	St s a Bool -> St s a a -> RangeR n w a -> St s a (Maybe (RangeR v w a))
unfoldlRangeMaybeWithBaseGen p f =
	runStateR . unfoldlMRangeMaybeWithBase (StateR p) (StateR f)

unfoldlMRangeMaybe :: (Unfoldl 0 v w, Monad m) =>
	m Bool -> m a -> m (Maybe (RangeR v w a))
unfoldlMRangeMaybe p f = unfoldlMRangeMaybeWithBase p f NilR

{-^

It is like @unfoldlRangeMaybe@. But it use a monad instead of a function.
The first argument monad returns a boolean value.
It creates values while this boolean value is @True@.
If this boolean value is @False@ before to create enough values or
@True@ after to create full values, then @unfoldlMRangeMaybe@ returns Nothing.

>>> :set -XDataKinds
>>> :module + Data.IORef
>>> r <- newIORef 1
>>> check n0 = (< n0) <$> readIORef r
>>> count = readIORef r >>= \n -> n * 3 <$ writeIORef r (n + 1)
>>> unfoldlMRangeMaybe (check 2) count :: IO (Maybe (RangeR 3 5 Integer))
Nothing

>>> writeIORef r 1
>>> unfoldlMRangeMaybe (check 5) count :: IO (Maybe (RangeR 3 5 Integer))
Just ((((NilR :++ 12) :+ 9) :+ 6) :+ 3)

>>> writeIORef r 1
>>> unfoldlMRangeMaybe (check 10) count :: IO (Maybe (RangeR 3 5 Integer))
Nothing

-}

---------------------------------------------------------------------------
-- ZIP
---------------------------------------------------------------------------

-- CLASS AND INSTANCE

class ZipR n m v w where
	zipWithMR :: Monad q =>
		(a -> b -> q c) -> RangeR n m a -> RangeR v w b ->
		q (RangeR (n - w) (m - v) a, RangeR v w c)

	{-^

	It is like @zipWithR@.
	But it uses a function which returns a monad instead of a simple value.

	>>> :set -XDataKinds
	>>> ns = NilR :++ 1 :+ 2 :+ 3 :+ 4 :+ 5 :+ 6 :: RangeR 5 7 Int
	>>> cs = NilR :++ 'a' :+ 'b' :+ 'c' :: RangeR 2 4 Char
	>>> zipWithMR (\n -> putStrLn . replicate n) ns cs
	cccccc
	bbbbb
	aaaa
	(((NilR :++ 1) :++ 2) :+ 3,((NilR :++ ()) :+ ()) :+ ())

	-}

instance ZipR n m 0 0 where zipWithMR _ xs NilR = pure (xs, NilR)

instance {-# OVERLAPPABLE #-} (
	1 <= n, LoosenRMin n m (n - w), LoosenRMax (n - w) (m - 1) m,
	ZipR (n - 1) (m - 1) 0 (w - 1) ) => ZipR n m 0 w where
	zipWithMR _ xs NilR = pure (loosenRMin xs, NilR)
	zipWithMR (%) (xs :+ x) (ys :++ y) =
		x % y >>= \z -> (loosenRMax *** (:++ z)) <$> zipWithMR (%) xs ys

instance {-# OVERLAPPABLE #-} (
	1 <= n, 1 <= v, v <= m, w <= n,
	ZipR (n - 1) (m - 1) (v - 1) (w - 1) ) => ZipR n m v w where
	zipWithMR (%) (xs :+ x) (ys :+ y) =
		x % y >>= \z -> ((:+ z) `second`) <$> zipWithMR (%) xs ys

-- FUNCTION

zipR :: ZipR n m v w => RangeR n m a -> RangeR v w b ->
	(RangeR (n - w) (m - v) a, RangeR v w (a, b))
zipR = zipWithR (,)

{-^

To recieve two lists and return a tuple list and rest of the first list.
The second list must be shorter or equal than the first list.

>>> :set -XDataKinds
>>> sampleZipR1 = NilR :++ 1 :+ 2 :+ 3 :+ 4 :+ 5 :+ 6 :: RangeR 5 7 Integer
>>> sampleZipR2 = NilR :++ 3 :+ 2 :+ 1 :: RangeR 2 4 Integer
>>> zipR sampleZipR1 sampleZipR2
(((NilR :++ 1) :++ 2) :+ 3,((NilR :++ (4,3)) :+ (5,2)) :+ (6,1))
>>> :type zipR sampleZipR1 sampleZipR2
zipR sampleZipR1 sampleZipR2
  :: (RangeR 1 5 Integer, RangeR 2 4 (Integer, Integer))

-}

zipWithR :: ZipR n m v w => (a -> b -> c) -> RangeR n m a -> RangeR v w b ->
	(RangeR (n - w) (m - v) a, RangeR v w c)
zipWithR op = (runIdentity .) . zipWithMR ((Identity .) . op)

{-^

It is like @zipR@.
But it evaluates a function to make values instead of puts together in tuples.

>>> :set -XDataKinds
>>> sampleZipWithR1 = NilR :++ 1 :+ 2 :+ 3 :+ 4 :+ 5 :+ 6 :: RangeR 5 7 Integer
>>> sampleZipWithR2 = NilR :++ 7 :+ 6 :+ 5 :: RangeR 2 4 Integer
>>> zipWithR (+) sampleZipWithR1 sampleZipWithR2
(((NilR :++ 1) :++ 2) :+ 3,((NilR :++ 11) :+ 11) :+ 11)
>>> :type zipWithR (+) sampleZipWithR1 sampleZipWithR2
zipWithR (+) sampleZipWithR1 sampleZipWithR2
  :: (RangeR 1 5 Integer, RangeR 2 4 Integer)

-}