[Savannah-hackers] Stow question

[Paul Company]

Can someone give me a description of what
the following subroutines do:
  CoalesceTrees and EmptyTree

And in subroutine Unstow, can someone explain
the variables:
  $pure, $subpure, $othercollection, and $subother

and the last line:
  if ((!$pure || !$targetdir) && @puresubdirs) {
    CoalesceTrees($targetdir, $stow, @puresubdirs);
  };

I try to unlink a package and end up in
EmptyTree where it runs DoUn