Jecel -

>>If saving memory isn't a priority, there is always the Self way of
>>hashing. Dedicate some 12 to 16 bits in the header of each object
>>and fill it in from some counter or random number generator when
>>the object is created and never change it after that.
>>
>>Of course, given Squeak's compact headers I don't think this is
>>the way to go here.

FYI, this is EXACTLY what Squeak does.  Every object has 12 bits of hash, and we manage to squeeze them into the 1-word headers along with everything else!

	- Dan