use strict;
use warnings;
use feature 'say';

use Algorithm::Combinatorics qw( combinations_with_repetition );

package Algorithm::Combinatorics {

no warnings 'redefine';

sub main::combinations_with_repetition {
    my ($data, $k, $ref) = @_;
    __check_params($data, $k);

    return __contextualize(__null_iter()) if $k < 0;
    return __contextualize(__once_iter()) if $k == 0;

    my @indices = $ref ? @$ref : (0) x $k;
    my $iter = Algorithm::Combinatorics::Iterator->new(sub {
        __next_combination_with_repetition(\@indices, @$data-1) == -1 ? undef : [ @{$data}[@indices] ];
    }, [ @{$data}[@indices] ]);

    my $x = __contextualize($iter);  # Note: scalar context forced
    return [ $x, \@indices ]         # + interface changed
}
}
 
my @data = qw( a b c );
 
my ( $iter, $secret ) = 
    @{ combinations_with_repetition( \@data, 3 )};

say @{ $iter-> next } for 1..5;

my ( $iter_2 ) = 
    @{ combinations_with_repetition( \@data, 3, $secret )};

say '**********';

$iter_2-> next;     # skip 1
while ( my $p = $iter_2-> next ) { say @$p }

__END__

aaa
aab
aac
abb
abc
**********
acc
bbb
bbc
bcc
ccc