On Thu, Jul 11, 2013 at 2:58 PM, Vlatko Basic <vlatko.basic@gmail.com> wrote:

Hm, I thought it is a pattern match with constant, as in f ('a':xs) ==

I wonder what you'd make of this definition, then?

(*) `on` f = \x y -> f x * f y

According to the enlightenment above, I'd say (*) is a variable that holds some function/operator that is applied on (f x) and (f y), not the multiplication, right?

Correct. But if it's a variable there, why would you expect it to be a constant in a different pattern?