On Tue, 2002-09-03 at 23:57, Luke Palmer wrote:
> On Tue, 3 Sep 2002, Brent Dax wrote:
> > 
> > How can you be sure that <roundascii> is implemented as a character
> > class, as opposed to (say) an alternation?
> 
> What's the difference? :)
> 
> Neglecting internals, semantically what I<is> the difference?
> 

One *possible* semantic difference is a guaranteed matching order.
Nothing (historically) has ever really dictated that character classes
must match left-to-right, as alternation does.

That's mainly because character classes have always been of a uniform
width, in which case it is only going to match one thing and one thing
only.  Whether that will be an issue with variable-width characters in a
class is largely going to rely on the semantics that are dictated.

-- 
Bryan C. Warnock
bwarnock@(gtemail.net|raba.com)

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