I don't even understand what you are trying to do :)
if you want to pattern match on the empty list
foo :: [a] -> [a]
foo [] = 0
foo (x:xs) = undefined
if you want to use the guard syntax
foo xs | null xs = 0
| otherwise = undefined
Ben
On 12 July 2011 10:02, Roelof Wobben
<rwobben@hotmail.com> wrote:
hello
Everyone thanks for the help.
I'm now trying to make this work on a empty list.
But my question is.
When the definition is :
[a] -> [a] [a]
Is it correct that I don't can use.
length xs = 0 | []
Roelof
----------------------------------------
> Subject: Re: [Haskell-beginners] function defenition. Do I understand it right?
> From: d@vidplace.com
> Date: Mon, 11 Jul 2011 18:56:42 -0400
> CC: beginners@haskell.org
> To: rwobben@hotmail.com
>
> On Jul 11, 2011, at 5:13 PM, Roelof Wobben wrote:
>
> > What I try to achieve is this:
> >
> >
> >
> > [1,2,3,4] will be [1,2] [3,4]
> >
> > [1,2,3,4,5] will be [1,2,3] [3,4,5]
>
> So, I think what you want is this http://codepad.org/kjpbtLfR
>
> Is that correct?
_______________________________________________
Beginners mailing list
Beginners@haskell.org
http://www.haskell.org/mailman/listinfo/beginners