On Nov 4, 2004, at 8:04 PM, Mark Hubbart wrote:

> Regular expressions, by all standard definitions, aren't recursive.
> Perl's regexen have been extended to allow it, but it really isn't
> considered a standard regex feature.

Of course, you are correct.  However, recursive "Regular Expressions" 
are becoming fairly common place now.  Ruby's next regex engine will 
support them as well.

Regular Expression has evolved considerably from the original 
definition, with recursive capabilities being just another change in a 
long line of added usefulness.  Does that really means they cease to be 
Regular Expressions?  Longhorn will still be Windows, right?

I think of it more in terms of supersets or, for a programming slant, 
subclassing.  The spirit of Regular Expressions, patterns to 
locate/breakdown text, is intact, I believe.  They're just even more 
handy now.

Just my two cents.

James Edward Gray II

P.S.  Proving whether or not Perl 6 changes will still be "Regular 
Expression" is left as an exercise for the reader.  ;)