The dreaded M-R

[Jacques Carette]

Cale Gibbard wrote:
> Hmm... however, could we not assign to each instance a unique
> identifier which could be compared? Say a cryptographic hash of the
> source code for the instance? (Which of course would never be exposed
> to the user.) That should be enough to tell them apart.
By the way, this is the method used by Computer Algebra Systems.  
However, it is really unclear if the cost is worth it, in memory as well 
as in CPU time.  When you are doing a lot of "expression manipulation", 
this seems worth it, but for more general program execution, it seems 
not to be.

Personally I think that this ought to be resolved by static means -- and 
yes, by the linker, as it can't be done properly earlier.

Jacques