#!/usr/bin/env perl
 
 use warnings;
 use 5.014;
 
 use Algorithm::Loops qw/NestedLoops/;
 use Benchmark qw/:all/;
 
 my @SKU     = (1..5);
 my @shirt   = qw/T S L H/;
 my @size    = qw/S M L XL 2X/;
 my @col     = qw/BLU GRN WHT BLK/;
 
 say scalar algorithm_loops();
 say scalar nested_loops();
 say scalar do_glob();
 
 cmpthese(-10, {
     'Algorithm::Loops' => \&algorithm_loops,
     'Nested loops'     => \&nested_loops,
     'glob'             => \&do_glob,
     });
 
 sub algorithm_loops {
     return NestedLoops([ \@SKU, \@shirt, \@size, \@col ],
                 sub { 'SKU' . join '', @_ });
 }
 
 sub nested_loops {
     my @r;
     for my $sku (@SKU) {
         for my $shirt (@shirt) {
             for my $size (@size) {
                 for my $col (@col) {
                     push @r, 'SKU'.$sku.$shirt.$size.$col;
                 }
             }
         }
     }
     return @r;
 }
 
 sub do_glob {
     () = glob 'SKU{'.join(',',@SKU).'}{'.
                      join(',',@shirt).'}{'.
                      join(',',@size).'}{'.
                      join(',',@col).'}';
 }