Hello, Are there limitations to the regex matching capabilities in Perl? I came across a case today where a string wouldn't match, and I couldn't figure out why. I finally tried removing part of the source file and it matched! So it seems as though the size of the source file and/or the size of the match is limited somehow. The match would have been about 50 kb. The expression was the following : 
s/class \s+ (?<class_name> \w+) \s* 
(\: (\s* \w*)? \s* (?<ancestor> \w+))? \s* 
$braces
//x

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where $braces was defined as : 
 
$braces = qr/(?<braces>\{ ([^\{\}] | (?&braces))*? \} )/x;

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It matched correctly if I simplified it to the following: 
s/class \s+ (?<class_name> \w+) \s* 
(\: (\s* \w*)? \s* (?<ancestor> \w+))? \s* 
\{ (?<class_body>  [\s\S]+ ) \} \s*;
//xm

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That wasn't acceptable however, because by removing the recursion, I was no longer able to match the braces correctly and it therefore failed if there were two sets of braces following each other (it greedily matched right up to the last closing brace. So basically, my question is what the limitations are that caused this problem. I realize that I'm pushing things to the limit and that at this point, it's probably better, just from a performance point of view, to split things up into smaller expressions by doing a bit of basic parsing by hand first (that's what I ended up doing, and it works fine). I did waste a good 2 hours trying to figure out why the regex wasn't working though, so I'd kind of like to know for next time what the limitations are... Thanks in advance, Jonathan

In reply to Perl regex limitations by jonneve

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