[Python-Dev] frozendict (was: Possible patch for functools partial...) (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Sun May 16 12:53:58 CEST 2010

On Sun, 16 May 2010 11:55:14 +1000 Yaniv Aknin <yaniv at aknin.name> wrote:

Is the whole notion of a frozendict worthy, given this limitation?

I don't think so. Of course we how have a more general problem:

if we choose to implement only equality testing for partials and leave hashing as is, then hashing isn't consistent with equality anymore -- which is unacceptable
if we choose to implement only equality testing for partials and make them unhashable, we are breaking programs which store partials in a set or a dict

So we are left with the following choice:

implement hashing consistently with equality testing, even though the keyword arguments can be changed later. I think this is acceptable from a practicality standpoint
abandon the whole idea of improving equality testing

Regards

Antoine.