Dan Doel wrote:
If you do want to generalize (.), you have to decide whether you want to generalize it as composition of arrows, or as functor application. The former isn't a special case of the latter (with the current Functor, at least).
By annotating functors with the category they operate on, you can reconcile both seemingly different generalizations
class Category (~>) => Functor (~>) f where (.) :: (a ~> b) -> (f a -> f b) -- functor application instance Functor (->) [] where (.) = map -- arrow composition instance Category (~>) => Functor (~>) (d ~>) where (.) = (<<<) Regards, apfelmus _______________________________________________ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime