________________________________
Date: Mon, 27 Jun 2011 16:14:28 +0100 Subject: Re: [Haskell-beginners] Do I understand this well From: colinpauladams@gmail.com To: rwobben@hotmail.com
No.
You are onfusing defining a function with using it.
addVectors (x1, y1) (x2, y2) = (x1 + x2, y1 + y2)
defines the function addVectors
(x, y) = addVectors (3.0, 4.5, -3.4, -5.6)
calls the function, and binds x and y to the components of the result (pattern matching).
Alternatively:
fst . addVectors (3.0, 4.5, -3.4, -5.6)
will return the x-compnent of the result (by composing functions)
Oke, I understand that I think But when I ghci I enter : (x, y) = addVectors (3.0, 4.5, -3.4, -5.6) after I made a file with the file defenition. I get this error : :1:7 parse error on input = So something is not right here. Roelof