[ImNotAKompjoetr]

because in haskell functions are curried,

  function_name :: param1 -> param2 -> return

is a function that if you only give it param1 it returns a function that takes an argument of param2Type and returns returnType. This way you can easily compose functions

[conceit]

parans make it more obvious:

f :: param1 -> (param2 -> return)

ret = (f p1) p2