[Haskell-beginners] Applicative Composition
edgar klerks
edgar.klerks at gmail.com
Thu Sep 30 19:47:09 EDT 2010
Hi All,
I was wondering, why there isn't a composition operator for applicative
functors. Of course it is rather trivial to implement, but it is a useful
feature:
{-# LANGUAGE FlexibleInstances, UndecidableInstances #-}
module ApplicativeComposition where
import Control.Applicative
class (Applicative f) => ApplicativeComposition f where
(<.>) :: f (b -> c) -> f (a -> b) -> f (a -> c)
instance (Applicative f) => ApplicativeComposition f where
(<.>) f g = pure (.) <*> f <*> g
Can this be added to later versions of haskell?
Greets,
Edgar
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