On Mon, Sep 18, 2006 at 02:51:34AM -0700, Carajillu wrote:
Hi, I'm a student and I have to do a program with Haskell. This is the first time I use this languaje, and I'm having problems with the indentation. I want to check if this function is correct, but when I try to make the GHCi interpret it, I get "line 18:parse error (possibly incorrect indentation)"
The function is:
...
if x == e then return l2
I did not understand what you are trying to do, anyway the error message is due to the expression above, and not to indentation. The Haskell if constructions is: "if ... then ... else", and else cannot be missing. Moreover, "return" is not a way to return a value. It is a special function that works with the monad class. Actually it is one of the two methods of the monad class, and it inserts a value into a monad. As far as your code goes, I'd suggest you to read some tutorials, like "The Gentle Introduction", or "Hasekll for C Programmers". Have a look here: http://haskell.org/haskellwiki/Learning_Haskell and here http://haskell.org/haskellwiki/Books_and_tutorials Hope this helps. Andrea