[Python-Dev] Add a frozendict builtin type

[André Malo]

* Guido van Rossum wrote:

> On Thu, Mar 1, 2012 at 9:44 AM, Victor Stinner <victor.stinner at gmail.com> 
wrote:
> > frozendict would help pysandbox but also any security Python module,
> > not security, but also (many) other use cases ;-)
>
> Well, let's focus on the other use cases, because to me the sandbox
> use case is too controversial (never mind how confident you are :-).
>
> I like thinking through the cache use case a bit more, since this is a
> common pattern. But I think it would be sufficient there to prevent
> accidental modification, so it should be sufficient to have a dict
> subclass that overrides the various mutating methods: __setitem__,
> __delitem__, pop(), popitem(), clear(), setdefault(), update().

For the caching part, simply making the dictproxy type public would already 
help a lot.

> What other use cases are there?

dicts as keys or as set members. I do run into this from time to time and 
always get tuple(sorted(items()) or something like that.

nd
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