[Python-Dev] Non-string keys in namespace dicts

Neil Toronto ntoronto at cs.byu.edu
Tue Dec 4 07:12:48 CET 2007

I apologize - I had forgotten what you were telling me by the time I 
replied. Here's a better answer.

> Phillip J. Eby wrote:
>> At 03:26 PM 12/3/2007 -0700, Neil Toronto wrote:
>> Actually, you're missing the part where such evil code *can't* muck 
>> things up for class dictionaries.  Type dicts aren't reachable via 
>> ordinary Python code; you *have* to modify them via setattr.  (The 
>> __dict__ of types returns a read-only proxy object, so the most evil 
>> rich compare you can imagine still can't touch it.)

C code can and does alter tp_dict directly already. If caching were 
implemented within type's setattr, all these places would have to be 
changed to use setattr only. That doesn't seem so bad at first. It's a 
change in convention, certainly: a new informal rule that says "no 
monkeying with a PyTypeObject's tp_dict, period". Lack of observance 
could be difficult to debug, as a PyDict_SetItem would appear to have 
worked just fine to C code but not show up to Python code.


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