#!/usr/bin/perl
use warnings;
use strict;

# Pm node 1211055

my $n = 3;
my @b = qw( a b );

my $iter = variations_rep_iter(\@b, $n);

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


sub variations_rep_iter {
    my ($bases, $n) = @_;
    
    my @indices = (0) x $n;
    my $first = 1;

    my $iter = sub {
        if ($first) {
            $first = 0;
            return [ @$bases[ @indices ] ];
        }
        
        my $r = $#indices;
        while ($r >= 0) {
            if (++$indices[$r] > $#$bases) {
                $indices[$r--] = 0;
            } else {
                last
            }
        }
        return if $r < 0;

        return [ @$bases[ @indices ] ];
    };  
    return $iter;
}