You could take a look at the WeakDictionary that ships in a standard
Squeak image, if there isn't already one lying around in Pharo. There
are several classes using weak references.

I will look at squeak stuff.
But my question more about about conceptual problem: I need week dictionary which values has reference to it key. Can it be really week?
I think it can be kind of "ephemeron problem" and such dictionary contents will never be garbaged. Is ephemerons supported by latest vm?

In pharo I see two classes: WeakKeyDictionary and WeakValueDictionary.
What you think I should use to implement my requirements: cache which can be cleaned by garbage collector due to weak keys or values?

2012/11/27 St�phane Ducasse <stephane.ducasse@inria.fr>
Ghost

I think it is just implementation of very skin proxy objects?
Is it related to weak dictionary cache?