[Python-Dev] sizeof(long) != sizeof(void*)

[Tim Peters]

[Samuele Pedroni]
> but that something like id() can be cheaply offered/exposed is very
> much a characteristic of the underlying GC implementation that is
> being exploited (objects don't move),

The docs for id() just promise a unique integer; it needn't be a memory
address.

> and the GC impl is an overall implementation detail.
>
> I have just gone through implementing a correct id() for Jython.
>
> For the serious usage id() would be better substituted by an identity
> mapping implementation

Sorry, I don't know what that means, and a unique integer seems to be what
most users of id() are looking for.

> which initially for CPython could simply be using id(). But the user would
use
> that and not rely on id().

As above, the identity-mapping business lost me.

> ...