bench.pl

use strict;
use warnings;
use Benchmark qw(:all);

my $alphabet = 'STKPWHRAO*#EUFRPBLGTS';
my $re = qr/^S?T?K?P?W?H?R?A?O?\*?#?E?U?F?R?P?B?L?G?T?S?\.?$/;

sub match_re {
    my $yesno = ($_[0] =~ $re) ;
    #print $_[0] . " " . ($yesno ? 'yes' : 'no') . "\n";
    return $yesno;
}
sub match_index {
    my $bad_word;
    my $last_pos = -1;
    foreach my $ch (split '', $_[0]) {
        $last_pos = index($alphabet, $ch, $last_pos + 1);
        if ($last_pos < 0) {
            $bad_word = 1;
            last;
        }
    }
    # print $_[0] . " " . ($bad_word ? 'no' : 'yes') . "\n";
    return $bad_word;
}

cmpthese 1_000_000, {
    're' => sub {
        match_re 'KAT';
        match_re 'FRAG';
        match_re 'TKPWAUL';
        match_re 'GAUL';
        match_re 'SAS';
        match_re 'SASS';
    },
    'index' => sub {
        match_index 'KAT';
        match_index 'FRAG';
        match_index 'TKPWAUL';
        match_index 'GAUL';
        match_index 'SAS';
        match_index 'SASS';
    }
};

          Rate    re index
re    102354/s    --   -5%
index 107296/s    5%    --