RFC: Collection framework.

Udo Stenzel u.stenzel at web.de
Tue Feb 14 13:59:03 EST 2006


Jean-Philippe Bernardy wrote:
> http://hackage.haskell.org/trac/ghc/wiki/CollectionClassFramework

I'm missing the equivalent of pattern matching the head of a list.  The
closest equivalent would be another method in class Collection:

	front :: c -> Maybe (o,c)

Algorithms that pattern match on a list could be expressed in terms of
'front' instead of 'toList' and a match.  In a sense, 'front' is to
'insert' as 'unfoldr' is to 'foldr', so it should be there as well,
though possibly under a better name.


Udo.
-- 
What nonsense people talk about happy marriages!  A man can be happy
with any woman so long as he doesn't love her.
                -- Oscar Wilde
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