Greetings stvn,

This is awesome. Thanks! I need to reprogram my brain so I'll think to use closures more readily. Maybe I need to re-read HOP. You make a great point about this being a destructive function. I think it's easy to fix, though:

$last_key = delete $_->{ $key_name };
push @{ $build_box }, $_;
[download]

...becomes...

push @{ $build_box }, $_;
$last_key = delete $build_box->[-1]{$key_name};
[download]

UPDATE: I'm a crazy idiot. This doesn't do what I claim it should do. Bad programmer. No cookie. All I'm doing is moving the reference. I need to deep copy instead.