Re: RE: Answer: What can regular expressions NOT do?

[Joey The Saint]

Well, I actually asked for something similar ages ago on comp.lang.perl.moderated (I wanted to match balanced braces in C++ code) and was treated to the following solution which works quite handily on arbitrary-depth nesting for parens.

$string = "((()()())";  # one unbalanced paren
($re = "\Q$string") =~ s/\\(\()|\\(\))/$1\\$1$2$2/g;
my @a = eval { $string =~ $re };
die "Mismatched brackets in '$string'\n" if $@;

-J.