[Haskell-cafe] WildCard question

Wolfgang Jeltsch wolfgang at jeltsch.net
Tue Apr 13 17:16:52 EDT 2004

Am Dienstag, 13. April 2004 16:07 schrieb Paul Cosby:
> Hi,
> I am very new to haskell and the program hugs and I am having problems
> using the wildcard operator _
> Every time I try to use it in an definition it says something like the
> symbol /017 is not recognised.

Are you sure that it says "/017"?  Maybe, it says "\017" or "\17".  If this is 
the case, it is because of a control character in your source file.

> I am sure my defintions are correct as I tested it with an example defintion
> from Alan Thompsons craft of functional programming book.

Could you post an example to this list?

> I am guessing that all the relevant modules have not been loaded properly.

I doubt that this is the reason.

> I have reinstalled hugs with full implementation and this has not helped. I
> am using a windows 98 PC.
> Any help suggestions? Or has anyone just got the wildcard definition which
> are could just paste into my scripts

Try, for example, the following:
    isZero :: Integer -> Bool
    isZero 0 = True
    isZero _ = False
It works with my installation of Hugs.

> Many thanks

Your welcome.


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