>	IdentityDictionary is what you want to use.  It will allow 
>Associations to be keys in just the way you want.
>	The changes you are suggesting to Association #= and #hash 
>are ill-advised.

Thanks for the info.  But at least in my case, I can't use an 
IdentityDictionary, because the Associations I was using for keys were 
built on the fly, and I needed equality comparison, not identity 
comparison.

I was actually using Association because it was an existing class with 
two inst vars (holding two values and equality comparison was all the 
behavior I required). I ended up wrapping my two values in an Array and 
using that as the key, instead.



     -- tim