At 13:32 -0400 07/11/2003, Bob Arning wrote:
>That Object is the <flag> used by WeakSet to mark empty spaces. I 
>was a bit surprised to see nils as well. Hmm...

As I understand things, which may be not at all, the nils are put 
there by the GC when an element of a WeakArray is garbage collected. 
The flag objects are put there by the Set implementation to make 
empty spaces, so that they can be distinguished from the nils.

	Andrew