Hi Roelof, On 10/11/14 10:10, Roelof Wobben wrote:
No problem .
Im strugelling to make acc work.
I try to say that if the input list has only 1 item the outcome is the head of that list. But doing
acc = Just (head a) or doing acc = Just (head acc) gives both that acc or a is not in scope The `a` in the type signature `acc :: a -> Maybe a -> Maybe a` is not a variable name, it is a type.
also doing acc x = Just (head x) gives a error messages that the types are not matching. :t Just (head x) Maybe a
:t acc x Maybe a -> Maybe a So, the compiler is right!
Roelof
-- Leza Morais Lutonda, Lemol-C Electronic and Telecommunication Engineer Software Development and Architecture Enthusiast http://lemol.github.io 50 Aniversario de la Cujae. Inaugurada por Fidel el 2 de diciembre de 1964 http://cujae.edu.cu