module Control.Morphism.Histo where
import Control.Functor.Algebra
import Control.Functor.Extras
import Control.Functor.Fix
import Control.Comonad
import Control.Comonad.Cofree
import Control.Morphism.Cata
histo :: (RunComonadCofree f w) => GAlgebra f w a -> FixF f -> a
histo = g_cata (distHisto id)
g_histo :: (RunComonadCofree h w, Functor f) => Dist f h -> GAlgebra f w a -> FixF f -> a
g_histo k = g_cata (distHisto k)
distHisto :: (RunComonadCofree h w, Functor f) => Dist f h -> Dist f w
distHisto k = anaCofree (fmap extract) (k . fmap outCofree)