Am Freitag 26 Februar 2010 17:37:30 schrieb Magnus Therning:

> It doesn't look like a complete piece of code so these comments aren't
> backed up by running it through GHCi or anything.
>
> On Fri, Feb 26, 2010 at 16:29, Florian Duret <flo.morphe@gmail.com>
wrote:
> > Hello,
> >
> >
> > I try to set up a verification on the number of arguments given to my
> > program, but keep on getting "Parse error in pattern"
> > Here is what my code looks like:
> > main :: IO()
> > main = do
> >     -- On commence par ouvrir le fichier SAC en mode binaire
> >     argsList <- getArgs
> >     if (length (argsList) == 0)

It's most likely harmless for argument lists (although there are other
cases), but

Don't Use

if (length list == 0)

Never. Jamais. Niemals.

Use

if (null list)

length has to traverse the entire list, which may take a long time.