Hmm, I did go the long way to do it, didn't I? :)
Thanks for the idea.

sub foo {
   print "hi mom\n";
   my $ptr = \&foo;
   *foo=sub {
       print "that was unneccessary:";
       $ptr->();
   };
}

foo();
foo();
[download]

Hmm, more Perl voodoo. I like it.