#!/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%     --
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