module Control.Functor.Composition where
import Control.Functor.Composition.Class
import Control.Functor.Exponential
import Control.Functor.Full
newtype CompF f g a = CompF { runCompF :: f (g a) }
instance Composition CompF where
compose = CompF
decompose = runCompF
#ifndef __HADDOCK__
type (f :.: g) a = CompF f g a
#endif
instance (Functor f, Functor g) => Functor (CompF f g) where
fmap f = compose . fmap (fmap f) . decompose
instance (ExpFunctor f, ExpFunctor g) => ExpFunctor (CompF f g) where
xmap f g = compose . xmap (xmap f g) (xmap g f) . decompose
instance (Full f, Full g) => Full (CompF f g) where
premap f = premap . premap $ decompose . f . compose
associateComp :: (Functor f, Composition c) => (c (c f g) h) a -> (c f (c g h)) a
associateComp = compose . fmap compose . decompose . decompose
coassociateComp :: (Functor f, Composition c) => (c f (c g h)) a -> (c (c f g) h) a
coassociateComp = compose . compose . fmap decompose . decompose