Applicative combinators.

src/Functor.hs

@@ -29,6 +29,9 @@ infixl 4 $>
 ($>) :: Functor f => f a -> b -> f b
 ($>) = flip (<$)
 
+(<<$>>) :: (Functor f, Functor g) => (a -> b) -> f (g a) -> f (g b)
+(<<$>>) = fmap . fmap
+
 void :: Functor f => f a -> f ()
 void x = () <$ x
 #endif