"Alexander Belopolsky" <[EMAIL PROTECTED]> wrote: > On 6/29/06, "Martin v. Löwis" <[EMAIL PROTECTED]> wrote: > >... dict is more basic, set is just a special case of > > dict for performance reasons. Also, dict is used to define and implement > > the language itself, set is "just" a predefined type. > > > I guess it can be seen either way, just as a chicken and an egg. Does > python-3000 still plan to integrate sets and dicts so that a set is a > view of a dict? That would support the view that a set is more basic > (dict code will depend on set code but not the other way around).
I don't think that makes sense. I see a basic structure as one that can be used to implement other structures. A dict can emulate a set, but a set cannot emulate a dict. Thus, a set is a specialization of a dict with fewer features than the regular dict. > If set has better performance than dict (which I have not noticed so > far), it will be appropriate to use it in the language implementation > where it can replace a dict. The prime example is the "interned" > dict. The performance, I believe, is based on a Python 2.5 optimization that reduces memory consuption per entry from 12 to 8 bytes per entry. > > ... It is by design that you can use the dict API everywhere, since > > dict is part of the language itself. set wasn't designed with such a > > goal (the same is true for many other types, I would guess). > > That's probably the hart of my proposal. I would like to see sets > usable as a part of the language, or an application that embeds the > language everywhere where dicts can be used today. I disagree. You can get everything you need with a dict, and making sets a part of the language (besides being a builtin type), would necessarily add more overhead and maintenance to the language for little gain. If you need set-like functionality, and you need it to not be finalized, use a dict; it is available today, can do all the same things, and you don't need to wait at least 1.5 years until Python 2.6 is out. - Josiah _______________________________________________ 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
