I am trying to wrap my mind around dynamic regular expressions, and am having problems. I am trying to see how to get a recursive expression using (??{}), so I am trying to write a simple case for matching an increasing sequence of numbers, i.e. 23456. I have tried

perl -e "my $c; $c = qr/ ( \d | (??{ $c++ }) )* /x; '2345654321' =~ $c; print $&;"

I get 2345654321. I wanted 23456.

Is there a problem with the scope of $c inside the expression? Is it that the * will just match all the \d it sees?

I have read perlre, Mastering Regular Expressions 2nd ed. Chapter 7, and searched the net on dynamic regexes, and cannot find sufficient explanations.

I am limited to Perl 5.8 and no, I would never use $& in anything but a one-liner.

In reply to Regex to match ascending sequence by ExReg

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