You may could experiment with (??{ code }) 

#!/usr/bin/perl

my $test = "4321234";

if ($test =~ m/(\d)((??{ $1 + 1}))/) {
    print "matched $1 $2 \n";
}
__END__
matched 1 2

[download]

regards,
tomte

Hlade's Law:

If you have a difficult task, give it to a lazy person --
they will find an easier way to do it.

In reply to Re: regexp for searching incremental expressions by Tomte
in thread regexp for searching incremental expressions by mod_alex

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