#!/usr/bin/perl -w

use strict;
use Benchmark qw(cmpthese);

my $pattern=join "|",qw(a ab abc abcde ef gh ghij qrst nqmz stuv);
my $qr=qr/$pattern/;
my @candidates=qw(abc zzz stuv asasdfasdfaf qqqqqqqqqqqqqqqq lkasjh adsd qqqqqqqqqqqqabc);

sub preComp {
    my $result=scalar grep /$pattern/o,@candidates;
    return $result;
}

sub preCompQR {
    my $result=scalar grep /$qr/o,@candidates;
    return $result;
}

sub noPrecomp {
    my $result=scalar grep /$pattern/,@candidates;
    return $result;
}

print "Working from pattern '$pattern', qr='$qr'\n";
print "preComp finds ",preComp(),"\n";
print "preCompQR finds ",preCompQR(),"\n";
print "noPrecomp finds ",noPrecomp(),"\n";

cmpthese(-3,
        {
            preComp   => \&preComp,
            preCompQR => \&preCompQR,
            noPrecomp => \&noPrecomp
         }
     );