#!/usr/bin/perl -w
use strict;
use Algorithm::Loops qw(NestedLoops);
use Benchmark qw(cmpthese);

#!/usr/bin/perl -w
use strict;
use Algorithm::Loops qw(NestedLoops);
use Benchmark qw(cmpthese);

my @symbols=(
['abc','def','ghi'],
['abc','def','ghi'],
['abc','def','ghi'],
['abc','def','ghi'],
['abc','def','ghi'],
['abc','def','ghi'],
);

sub sorted {
	my $symbols = shift;
	
	my @all;
	my $iter = NestedLoops(\@symbols);
	my @list;
	while (@list = $iter->()) {
		my @sortedList = sort @list;
		my $listString = join ('',@sortedList);
		push @all, $listString;
		}
	
	my @uniq = keys %{{ map { $_ => 1 } @all }};
	my @sortedUniq = sort (@uniq);
	}
	
sub hash {
	my $symbols = shift;

    my $iter = NestedLoops($symbols);
    my %seen;

    while (my @list = $iter->()) {
        my $listString = join ('',sort @list);
        $seen{$listString}++
    }

    my @sortedUniq = sort (keys %seen);
	}

sub combo {
	my $symbols = shift;

	my $combos = NestedLoops([
	  $symbols[0],
	  map {
	    my $_hold = $_;
	    sub {
	      [grep {$_ ge $_[$#_]} @{$symbols[$_hold]}]
	    }
	  } 1..$#symbols
	]);
	
	my @result;
	my @sortedUniq;
	push @sortedUniq, "@result" while @result = $combos->();
	}
	
cmpthese(1000, {
    sorted => sub { sorted(\@symbols) },
    hash  => sub { hash(\@symbols)},
    combo => sub { combo(\@symbols)},
});   

##########BENCHMARK########## 

         Rate sorted   hash  combo
sorted 59.6/s     --   -26%   -94%
hash   80.8/s    36%     --   -91%
combo   926/s  1455%  1045%     --