How Regular Expressions work

Monday, December 3. 2007

How Regular Expressions work

This isn't an article about how to use regexes; you've probably seen plenty of those already. It's about how you would write a regex package from scratch, in a language like C that doesn't already have regexes.

I'll demonstrate a new module, Regex.pm, which implements regexes from nothing, in Perl. This will give you an idea of how regex matching is possible, although the details differ rather substantially from what Perl actually does.