[Python-Dev] Re: pre-PEP [corrected]: Complete, Structured Regular Expression Group Matching (original) (raw)

Erik Heneryd erik at heneryd.com
Tue Aug 10 15:00:50 CEST 2004

Fredrik Lundh wrote:

a regular expression defines a set of strings, and the RE engine is designed to tell you if a string you have is a member of this set. the engine's not a parser,

Well, as you know (and point out now and then), regexes aren't regular expressions in the CS sense. And most people don't use em just to see if a string matches or not, but to see what parts matches waht.

you're probably better off using the scanner mechanism:

http://effbot.org/zone/xml-scanner.htm or the sre.Scanner class (see the source code). the scanner concept could need some documentation, and it would be nice to be able to switch patterns during parsing. (time for a scanner PEP, anyone?)

I'd love to see scanners as an official part of the stdlib. Isn't this just a matter of documentation?

Erik

More information about the Python-Dev mailing list