[Haskell-beginners] matching the output of a standard function
to my function definition (non-exhaustive pattern problem)
byorgey at seas.upenn.edu
Mon Sep 27 12:21:08 EDT 2010
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!
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'.
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