Corion pointed out that this approach does "action at a distance", which you probably can't entirely avoid unless you do symbol table hackery.

Actually that's what I (wanted in the first place and) wanted to point out myself in my previous reply -except that I forgot to- to the effect that if I was to adopt that technique, then I would put a well visible comment (and I'm the "self explaining code does not need comments" kinda guy!) besides our $worker_pkg; (or my...)