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)