use strict;
use warnings;
use Algorithm::Combinatorics qw(combinations variations_with_repetition);

my @data = ('A', 'B', 'C', 'D', 'E', 'F');
my $cardinality = 2;


for my $cardinality (1..3) {

    print "\n\nCardinality: $cardinality\n";

    my $dataref = getPairsOfCombinations(\@data, $cardinality);

    if ($dataref == 0) {
        die "Bad return\n";
    }

    for (my $i = 0; $i < scalar(@$dataref); $i++) {

        print "( " .  join( ',', map {  "( " . join(',', @{$_}) . " )"  }   @{ $dataref->[$i] }  ) .  " )\n";

    }
}

exit(0);


sub getPairsOfCombinations {
    my ($data, $cardinality) = @_;

    my @combinations = combinations(\@data, $cardinality);
    my @variations = variations_with_repetition([0..$#combinations], 2);

    return [ map { [ map { $combinations[$_] } @{$_} ] } @variations ];
}