[Python-Dev] Add a frozendict builtin type (original) (raw)

André Malo nd at perlig.de
Thu Mar 1 21:27:17 CET 2012

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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