Hello Mauricio, Wednesday, September 10, 2008, 4:07:41 PM, you wrote: > Do you have any reference for that use of infixing > constructors by start their name with ':'? That's > interesting, and I didn't know about it. really? ;) sum (x:xs) = x + sum xs sum [] = 0 -- Best regards, Bulat mailto:Bulat.Ziganshin at gmail.com