>This is nothing better than current sets, because you allowing sets to
>contain nil, but at the same time disallow MetaNil instance to be
>included into a set as an element.
>My point is to make sets which can contain ANY object without discrimination.

Not exactly.  Yes, MetaNil is an object, since everything in Smalltalk is an
object.  But by definition MetaNil should not be used anywhere other than as
this place holder in Sets (or other collection objects that may need it).
MetaNils should never find there way outside of these collections.  If someone
is foolish enough to use them elsewhere, they get what they deserve.

Lou
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Louis LaBrunda
Keystone Software Corp.
SkypeMe callto://PhotonDemon
mailto:Lou at Keystone-Software.com http://www.Keystone-Software.com