Yours is a Frequently Asked Question. The answer to it can be found in the standard Perl documentation by using the command perldoc -q balanced, also known as:

Can I use Perl regular expressions to match balanced text?

   Although Perl regular expressions are more powerful than
   "mathematical" regular expressions because they feature
   conveniences like backreferences ("\1" and its ilk),  
   they still aren't powerful enough--with the possible 
   exception of bizarre and experimental features in the 
   development-track releases of Perl. You still need to 
   use non-regex techniques to parse balanced text, such as 
   the text enclosed between matching parentheses or 
   braces, for example.

   An elaborate subroutine (for 7-bit ASCII only) to pull 
   out balanced and possibly nested single chars, like "`" 
   and "'", "{"and "}", or "(" and ")" can be found in
            http://www.perl.com/CPAN/authors/id/TOMC/scripts/pull_quot
+es.gz

   The C::Scan module from CPAN contains such subs for   
   internaluse, but they are undocumented.

[download]

Further information can be found in perldoc -q How do I remove HTML which despite the name, is directly applicable to XML.

Regards,
Helgi Briem
helgi AT decode DOT is

In reply to Re: Balanced delimiter parsing by helgi
in thread Balanced delimiter parsing by moxliukas

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