In short, these need to be in a file. Take a look at YAHT (yet another haskell tutorial) which is under development and see if that answers any of your questions...if not, PLEASE let me know so I can update the tutorial so it does answer your questions. The tutorial is available off my web page http://www.isi.edu/~hdaume as a DVI, PS or PDF. - Hal -- Hal Daume III "Computer science is no more about computers | hdaume@isi.edu than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume On Fri, 26 Jul 2002, Pedro L. P. Dias wrote:
Dear Professor:
My name is Carlos Alexandre Grimaldi. I'm engineering student at Federal University of Rio de Janeiro, Brazil. I began my studies in Haskell, and I have some doubts which I report here. I'm very gratefully if you could help me. I'm following a book I downloaded from Internet: "A Gentle Introduction to Haskell, Version 98". Following this, I face some problems:
- "inc :: Integer -> Integer" don't work
- "inc n = n+1" don't work too;
- "data Bool = False | True" also...;
- "data Color = Red | Green | Blue | Indigo | Violet" also fails.
I thought that this commands and definitions must be inside a program, and don't at prompt "prelude>". So, I opened other book, also downloaded from Internet: "The Hugs 98 User Manual", and I tryed:
"module Fact where fact :: Integer -> Integer fact n = product [1..n]"
thinking that would be created a file "Fact", in which the definitions for "fact" would work. But this also yield an error... So, I ask you:
- is necessary the creation of a file where that definitions could work?
- is this file a ".hs"?
- how can I create a file like this? Which command or editor?
- or, if I wrong, why that examples don't work?
Thank you very much for your help. Best regards, Carlos A. Grimaldi.