strange behavor....

[Steve Holden]

On 11/16/2010 9:12 AM, Arnaud Delobelle wrote:
> Hrvoje Niksic <hniksic at xemacs.org> writes:
> 
>> mdw at distorted.org.uk (Mark Wooding) writes:
>>
>>>> So even if the globals() dictionary is custom, its __setitem__ method is
>>>> *not* called.
>>>
>>> Fascinating.  Thank you.
>>
>> In case it's not obvious, that is because CPython assumes the type for
>> many of its internal or semi-internal structures, and calls the
>> appropriate functions, such as dict.__setitem__ (PyDict_SetItem in C)
>> directly.  So python doesn't break the encapsulation of dict itself, it
>> just takes the liberty to assume that globals() is a non-subclassed
>> dict, at least as far as __setitem__ is concerned.
> 
> But it doesn't make this assumption for locals().
> 
That's because it reserves the right to optimize local storage without
extending the mapping to allowing item setting.

regards
 Steve

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