[Python-Dev] gc ideas -- sparse memory
Stephen J. Turnbull
stephen at xemacs.org
Sun Dec 5 09:17:37 CET 2010
"Martin v. Löwis" writes:
> > Why is useful to expose an identity hash? AFAICS it is *only* useful
> > in building an identity hash table. If so, why not just provide id()
> > or the is operator or both and be done with it?
>
> That's precisely James' point: Java provides the identity hash
> *instead* of the id() function (i.e. it does not have an equivalent
> of id()). Doing so gives greater liberties in implementing Java.
Yes, we understand that it makes the implementer's job easier. *Why
bother having an identity hash at all?* Having taken away id() and
provided maximum leisure to the implementer via
def identity_hash(object):
return 42
is there *any* benefit left for the user/developer? All I see is
costs: costs in implementation, costs in debugging. And AFAICS this
is a problem that can be solved once and reused by everybody who needs
id(); why does every developer need to write his own id() function?
More information about the Python-Dev
mailing list