Current Perl documentation can be found at perldoc.perl.org.

Here is our local, out-dated (pre-5.6) version:

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. You still need to use non-regexp 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_quotes.gz .

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