[Python-Dev] Add a frozendict builtin type

Thu Mar 1 21:27:17 CET 2012

* Serhiy Storchaka wrote:
> 01.03.12 16:47, André Malo написав(ла):
> > On Thursday 01 March 2012 15:17:35 Serhiy Storchaka wrote:
> >> This is the first rational use of frozendict that I see. However, a
> >> deep copy is still necessary to create the frozendict. For this case,
> >> I believe, would be better to "freeze" dict inplace and then
> >> copy-on-write it.
> >
> > In my case it's actually a half one. The data mostly comes from
> > memcache ;) I'm populating the object and then I'm done with it. People
> > wanting to modify it, need to copy it, yes. OTOH usually a shallow copy
> > is enough (here).
>> What if people modify dicts in deep?

that's the "here" part. They can't [1]. These objects are typically ROLists 
of RODicts. Maybe nested deeper, but all RO* or other immutable types.
I cheated, by deepcopying always in the cache, but defining __deepcopy__ for 
those RO* objects as "return self".
nd
[1] Well, an attacker could, because it's still based on regular dicts and 
lists. But thatswhy it's not a security feature, but a safety net (here).
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