What does uncurry ($) do?

Question

I\'m doing some excersises where I have to add a function\'s type and explain what it does. I\'m stuck with this:

phy = uncurry ($)

The typ

Answer 1

uncurry :: (a -> b -> c) -> (a, b) -> c

($) :: (a -> b) -> a -> b

uncurry ($) :: (a -> b, a) -> b

If you inspect types of uncurry and $ and its description:

uncurry converts a curried function to a function on pairs.

All it does is it takes a function (a -> b -> c) and returns a function that takes the parameters as a tuple.

So phy does the same thing as $, but instead of f $ x or ($) f x you call it like phy (f, x).