Leo Mello

Thank you Charles. The source code, available at the same link, is great. Now I understand why my code wasn´t running.

Regards

I also couldn't find the slides.

One of the links is this: http://www.comlab.ox.ac.uk/people/Richard.Bird/index.html

Another one is this: http://portal.acm.org/portal.cfm?coll=GUIDE&dl=GUIDE&CFID=63594272&CFTOKEN=61762843

Regards

Hello, I've tried the following code with Hugs:

type Parser a = String -> [(a,String)]

item :: Parser Char
item = \inp -> case inp of
               []     -> []
               (x:xs) -> [(x,xs)]
              
return' :: a -> Parser a
return' v = \inp -> [(v,inp)]

p' :: Parser (Char,Char)
p' = do x <- item
            z <- item
            y <- item
            return' (x,y)

It gives the following error: