Here is a module I use for solving little problems (it's in my Dr Dobbs toolkit) and I need a better name. Someday I might throw it in with my Combination module and Permutation module (both of which I also use for Dr Dobbs type problems), and then I'll need to figure out a namespace. For now, I just need to name this little guy.
package MixMatch;
use strict;
 
=comments
 
Takes an lref of lrefs like
 
[
  [a],
  [x, y, z]
  [1, 2]
]
 
and returns in order
  [a, x, 1]
  [a, x, 2]
  [a, y, 1]
  [a, y, 2]
  [a, z, 1]
  [a, z, 2]
 
=cut
 
sub new {
    my $self = bless {}, shift;
    my %args = (-array=>undef, # lref of lrefs
                @_);
 
    $self->{arr} = $args{-array};
    my $sizes = [];
    my $total = 1;
    foreach my $lref (@{$self->{arr}}) {
        push @$sizes, scalar(@$lref);
        $total *= $sizes->[-1];
    }
    $self->{rows} = scalar(@{$self->{arr}});
    $self->{sizes} = $sizes;
    $self->{count} = $total;
    return $self;
}
 
sub next {
    my $self = shift;
    my $c = $self->{count}--;
    return undef  unless $c;
    my $ret = [];
    for (my $i = 0; $i < $self->{rows}; $i++) {
        push @$ret, $self->{arr}->[$i]->[$c % $self->{sizes}->[$i]];
    }                             
    return $ret;
}

1;

[download]
I won't post my Permutation.pm here, it is 4x slower than Algorithm::Permute (which is a nice piece of XS), I just use mine because I like the order of permutations is produces. And yes, this module could be implemented in terms of Permute's, but it is so short that new()ing a few other objects seems like overkill

Suggestions?

-jackdied

In reply to Name Me! MixMatch? by jackdied

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