Alex Ferguson <[EMAIL PROTECTED]> writes:
> Is pattern-matching short strings (one or two characters) likely to be
> _vastly_ less efficient than matching against a single level of
> constructor? (Order of magnitude, plus.) Trying to make sense of some
> profiling numbers, here...
Quite possibly - pattern matching on strings involves building a
dictionary for Eq [Char], unpacking the string (it's represented as
packed in the object code), and performing the comparison. This is
probably bad.
Try replacing
f "aa" = ...
with
f ('a':'a':[]) = ...
Cheers,
Simon
--
Simon Marlow [EMAIL PROTECTED]
University of Glasgow http://www.dcs.gla.ac.uk/~simonm/
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