Probably best discussed on python-ideas... On Fri, Mar 18, 2011 at 4:04 PM, MRAB <pyt...@mrabarnett.plus.com> wrote: > Some of those who are relative new to regexes sometimes ask how to write a > regex which checks that a number is in a range or is a valid date. Although > this may be possible, it certainly isn't easy. > > From what I've read, Perl has a way of including code in a regex, but I > don't think that's a good idea > > However, it occurs to me that there may be a case for being able to call a > supplied function to perform such checking. > > Borrowing some syntax from Perl, it could look like this: > > def range_check(m): > return 1 <= int(m.group()) <= 10 > > numbers = regex.findall(r"\b\d+\b(*CALL)", text, call=range_check) > > The regex module would match as normal until the "(*CALL)", at which point > it would call the function. If the function returns True, the matching > continues (and succeeds); if the function returns False, the matching > backtracks (and fails). > > The function would be passed a match object. > > An extension, again borrowing the syntax from Perl, could include a tag like > this: > > numbers = regex.findall(r"\b\d+\b(*CALL:RANGE)", text, call=range_check) > > The tag would be passed to the function so that it could support multiple > checks. > > Alternatively, a tag could always be passed; if no tag is provided then None > would be passed instead. > > There's also the additional possibility of providing a dict of functions > instead and using the tag to select the function which should be called. > > I'd be interested in your opinions. > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > http://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > http://mail.python.org/mailman/options/python-dev/guido%40python.org >
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