Hi.

>How about: (in Set)
>hash
>	^self inject: 0 into: [:answer :each | answer bitXor: each hash]

Big set, slow hash. I would rather:

hash
	^self size > 10 
		ifTrue: [self size]
		ifFalse: [self inject: 0 into: [blablabla]]

And/or replace 10 by any other appropiate constant. I wonder what is the 
distribution of the size of the sets?

sizes := Bag new
Set allInstances do: [:each | sizes add: each size]
sizes size 384
average := sizes inject: 0 into: [:total :each | total + each]
average := average / sizes size
average (315/128)
average asFloat 2.4609375

sizes occurrencesOf: 0 10
sizes occurrencesOf: 1 197
sizes occurrencesOf: 2 122
sizes occurrencesOf: 3 12
sizes occurrencesOf: 4 14
sizes occurrencesOf: 5 4
sizes occurrencesOf: 6 8
sizes occurrencesOf: 7 4
sizes occurrencesOf: 8 3

"Yes, I'm going to use my own selector!"
sizes asSet asSortedCollection SortedCollection (0 1 2 3 4 5 6 7 8 9 10 11 
12 15 19 43 155 )

sizes occurrencesOf: 9 3
sizes occurrencesOf: 10 1
sizes occurrencesOf: 11 1
sizes occurrencesOf: 12 1
sizes occurrencesOf: 15 1
sizes occurrencesOf: 19 1
sizes occurrencesOf: 43 1
sizes occurrencesOf: 155 1

Well, 10 turned out to be quite good... what I don't understand quite fine 
is why are there so many sets with so few elements... about half of the 
existing sets have only 1 object inside them. Most sets have either 1 or 2 objects.

Andres.