category-extras-0.44.2: src/Control/Functor/Pointed/Indexed.hs

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-- |
-- Module	: Control.Functor.Pointed.Indexed
-- Copyright 	: 2008 Edward Kmett
-- License	: BSD3
--
-- Maintainer	: Edward Kmett <ekmett@gmail.com>
-- Stability	: experimental
-- Portability	: portable
--
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module Control.Functor.Pointed.Indexed 
	( IxPointed(..)
	, IxCopointed(..)
	, module Control.Functor.Indexed
	, module Control.Functor.Pointed
	)where

import Control.Functor.Pointed
import Control.Functor.Indexed

class IxFunctor m => IxPointed m where
        ireturn :: a -> m i i a

class IxFunctor w => IxCopointed w where
	iextract :: w i i a -> a

instance Pointed m => IxPointed (LiftIx m) where
        ireturn = LiftIx . point

instance Copointed m => IxCopointed (LiftIx m) where
        iextract = extract . lowerIx

{-# RULES
"ireturn/iextract" ireturn . iextract = id
"iextract/ireturn" iextract . ireturn = id
 #-}