Our regex engine is truly The Little Engine That Could! Nice idea, tye. Going back to the fundamentals often pays ;-) ...

Here is something similar I worked out for a statistics module that needed tie-adjusted ranks (a "tie" occurs in a list of numbers if two numbers have exactly the same value - something that most statistics algorithms don't really like because it violates their assumptions about continuous distributions).

sub ties {
    my @val =  sort @_;
    return () unless @val;
    my @delta = (1) x @val - 1;
    for (my $i = 1; $i < @val; $i++) {
        $delta[$i - 1] = $val[$i] - $val[$i - 1] ? 1 : 0;
    }
    my @ties = map {length} split /1+/, join '', @delta;
    shift @ties unless $ties[0];
    return map {++$_} @ties;
}
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Christian Lemburg
Brainbench MVP for Perl
http://www.brainbench.com