On Tue, 28 Feb 2012 12:07:32 +0000 Mark Shannon <m...@hotpy.org> wrote: > Antoine Pitrou wrote: > > On Tue, 28 Feb 2012 12:45:54 +0100 > > Victor Stinner <victor.stin...@haypocalc.com> wrote: > >>> I think you need to elaborate on your use cases further, ... > >> A frozendict can be used as a member of a set or as a key in a dictionary. > >> > >> For example, frozendict is indirectly needed when you want to use an > >> object as a key of a dict, whereas one attribute of this object is a > >> dict. > > > > It isn't. You just have to define __hash__ correctly. > > > >> frozendict helps also in threading and multiprocessing. > > > > How so? > > Inter process/task communication requires copying. Inter/intra thread > communication uses reference semantics. To ensure these are the same, > the objects used in communication must be immutable.
You just need them to be practically constant. No need for an immutable type in the first place. Regards Antoine. _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
