Thanks for all the replies! I tried adding the following test to see if I can get it working (as I said, I have now rewritten it to do the parsing by hand, but I would like to figure it out for next time):

 
$braces = qr/(?<braces>\{ ([^\{\}]++ | (?&braces))*+ \} )/x;
if ($h =~ s/class \s+ (?<class_name> \w+) \s* (\: (\s* \w*)? \s* (?<an
+cestor> \w+))? \s* $braces//x) {
   print "hi\n";
}
[download]

The match is never made however... The code I'm matching against is a C++ header file, and I'm looking for class definitions, formatted like this :

class MyClassName : public MyAncestorClass {
...
...
};
[download]

This expression works fine for smaller classes or for this same problem class if there are no braces inside the class definition. In this class however, I have the following declarations (C++ Builder code...) :

  __property TNotifyEvent OnMonaDocSaveToDB = {read=FOnMonaDocSaveToDB
+, write=FOnMonaDocSaveToDB};
[download]

If I remove that property declaration, it matches, if I leave it, it fails... Jonathan