On Thu, 29 Oct 2009, Gary Johnson wrote:
> Well, this depends on your language's literal representation of regexes.
> If they are just a string of white-noise (as per usual), then you can
> naturally write regexes to match that particular string of white-noise.
I'm not sure I'd say "naturally." There are plenty of languages that are
not regular and thus can't be matched by a regular expression. The
original question becomes: Does the set of regular expressions form a
regular language? The answer probably depends on just which regular
expression syntax you are talking about. I believe most practical regular
expression systems allow arbitrary nesting of matching parenthesis. If so
that's probably a show stopper. Normally such languages are not regular
(but are often context free).