use strict;
use warnings;

# 18-01-2010 
# cartesian product for 3 or more sets using Quantum::Superpositions


# works because BINARY in Q::S allows to make quantized functions like U and p.

sub p { return \@_; }

sub U  {
    my $i = $_[1];
    my @element; # an element of the cartesian product

    if(ref($i) eq 'ARRAY') {
        while(1){
            push @element,$i->[0];
            $i=$i->[1];
            last unless ref($i) eq 'ARRAY';
        }
    };

    @element=($_[0],@element,$i);

    print join(' ',@element)."\n"
    if ref($_[1]) eq 'ARRAY';
}

use Quantum::Superpositions 
BINARY         => ['main::U','main::p'];


#U(any(1..2),p(any(9..13),p(any(0..1),p(any(2..4),any(5..8)))));
U(any(1..2),p(any(2..4),any(5..10)));