use strict;
use Benchmark qw(cmpthese);
use List::Util;

## a 'reasonable' worst-case scenario?  first of list of twenty .. 
my @display_files = qw(
    one two three four five six seven eight nine ten eleven twelve thirteen 
    fourteen fifteen sixteen seventeen eighteen nineteen twenty
);
sub param { 'one' }

cmpthese( -2, {
    grep_param  => sub { 
        unless( grep { $_ eq param('select') } @display_files ) { 1; } 
    },
    param_grep  => sub { 
        my $select = param('select');
        unless( grep { $_ eq $select } @display_files ) { 1; } 
    },
    found => sub {
        my $select = param('select');
        my $found;
        foreach (@display_files) {
            if ($_ eq $select) {
                $found = 1;
                last;
            }
        }
        unless ($found) { 1; }
    },
    first => sub {
        my $select = param('select');
        my $found = List::Util::first { $_ eq $select } @display_files;
        unless ($found) { 1; }
    }
});