:: (c -> d) -> (a -> b -> c) -> a -> b -> d package:pointless-fun -is:exact

Binary composition: pass two args to the right argument before composing.

(f .: g) x y = f (g x y)

or,

f .: g = curry (f . uncurry g)

This is the same as the common idiom (f .) . g but more easily extended to multiple uses, due to the fixity declaration.