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Today's Topics:
1. Re: matching the output of a standard function to my
function definition (non-exhaustive pattern problem) (Brent Yorgey)
----------------------------------------------------------------------
Message: 1
Date: Mon, 27 Sep 2010 12:21:08 -0400
From: Brent Yorgey <[email protected]>
Subject: Re: [Haskell-beginners] matching the output of a standard
function to my function definition (non-exhaustive pattern
problem)
To: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii
On Mon, Sep 27, 2010 at 06:15:22PM +0200, Martin Tomko wrote:
> Dear Daniel
> that worked perfectly, thanks for the suggestion!
>
> One more question: how do you use null to check for empty lists?
> something like [] == null did not work ... just chekcing, I got my
> orignal code to work, thanks again!
> Martin
When in doubt, consult the types!
null :: [a] -> Bool
That is, null is a function for testing lists to see whether they are
empty. So rather than 'list == null' you write 'null list'.
-Brent
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