#!/usr/bin/perl
use strict;
use warnings;
use Benchmark qw( timethese cmpthese ) ;
no if $] >= 5.018, warnings => "experimental::smartmatch";

my @array = ("world", "today", "is nice");
my %hash = ( 0 => "Hello",
	     1 => "world",
	     2 => "today",
	     3 => "is" ,
	     4 => "nice" );

my @new_array;
my $results = timethese(1000000000, { 'map' => benchmarkMap(),
				      'grep' => benchmarkGrep(),
				      'foreach' => benchmarkForeach(),
				      'smartmatch' => benchmarkSmartMatch(), },
			'none');
cmpthese( $results ) ;

sub benchmarkSmartMatch {
    while (my ($key, $value) = each %hash) {
        push @new_array, $key if ($value ~~ @array);
    }
}

sub benchmarkGrep {
    while (my ($key, $value) = each %hash) {
        push @new_array, $key if (grep { /^$value$/ } @array);
    }
}

sub benchmarkForeach {
    while (my ($key, $value) = each %hash) {
	for (@array) {push @new_array, $key if ($value eq $_);}
    }
}

sub benchmarkMap {
    while (my ($key, $value) = each %hash) {
    map { if($value eq $_) { push @new_array, $key } } @array;
    }
}

__END__

Monks$ perl test.pl
                  Rate    foreach smartmatch       grep        map
foreach     76569678/s         --       -30%       -59%       -64%
smartmatch 109170306/s        43%         --       -42%       -49%
grep       187969925/s       145%        72%         --       -13%
map        215053763/s       181%        97%        14%         --