Your ARRRGH is correct. I believe your code will incorrectly pass the string "(()" because the second "(" qualifies for "." in the middle.

What you need is a dot that doesn't match any of your other items of interest. Perhaps (untested): 

$middle = "(?:(?!$left|$right|$escape$left|$escape$right).)";

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-- Randal L. Schwartz, Perl hacker

In reply to Re: Determining if you have balanced delimiters by merlyn
in thread Determining if you have balanced delimiters by Ovid

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