Re: [Haskell-beginners] safetail problem

Hello, I use Programming in Haskell from Graham Hutton. But I can't find anything in the first 4 chapters from that book why I must use (0,x) en what that means. Roelof ----------------------------------------

Date: Tue, 12 Jul 2011 15:21:46 -0400 Subject: Re: [Haskell-beginners] safetail problem From: amindfv@gmail.com To: rwobben@hotmail.com CC: beginners@haskell.org

_ isn't a value: it's a wildcard character for pattern matching.

Also, if x = [1,2,3], [0,x] is the wrong way to make a list. The right way is (0:x) (":" is "cons")

What resource are you learning from?

On 7/12/11, Roelof Wobben wrote:

...

Hello,

As a exercise I need to rewrite the tail function into a safetail function by using conditions.

So I made this : http://codepad.org/bKcCUdqy

But as you can see there is a error message.

Can anyone explain me how to solve this ?

Roelof

_______________________________________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/mailman/listinfo/beginners