nested subs

[Piers Cawley]

So, I was about to write the following test for Pugs:

  sub factorial (Int $n) {
    my sub factn (Int $acc, $i) {
      return $acc if $i > $n;
      factn( $acc * $i, $i+1);
    }
    factn(1, 1);
  }

When I thought to check the apocalypses and exegeses and, what do you know, I
couldn't find any evidence that nested named functions like this were legal. 

So, are they legal?

And yes, I know there are other ways of doing this, but I like the lack of
sigils on the function when you do it this way.