Re: Multiple Permutation handling

[ggoebel]

"Takes a list or array of array references and returns a function that will return successive permutations of the referenced arrays. Avoids recursion so will work on abitrarily huge sets of data. Runtime scales linearly with the number of sets. Minimal memory usage." -- shotgunefx w/ ariels

use strict;
use warnings;
use integer;


my @data = (
    ['SKU'],
    [1..5],
    [qw(T S L H)],
    [qw(S M L XL 2X)],
    [qw(BLU GRN WHT BLK)]
);
my $iter = make_permutator(@data);
my ($idx, @idx_link);

while (my @els = $iter->() ){
  print @els, "\n";
}

sub make_permutator {
  @idx_link = (0, @_);
  return sub {
    $idx = $idx_link[0]++;
    my @ret;
    for my $i (1..$#idx_link) {
      push @ret, $idx_link[$i][$idx % @{$idx_link[$i]}];
      $idx /= @{$idx_link[$i]};
    }
    return $idx ? () : @ret;
  }
}

1;
__END__