Python dynamic attribute creation

[Alexander Kapps]

Alexander Kapps wrote:
> Bruno Desthuilliers wrote:
>> Alexander Kapps a écrit :
>> (snip)
>>> While I personally don't agree with this proposal (but I understand 
>>> why some people might want it), I can see a reason.
>>>
>>> When disallowing direct attribute creation, those typos that seem to 
>>> catch newcommers won't happen anymore. What I mean is this:
>>>
>>> class Foo(object):
>>>     def __init__(self):
>>>         self.somearg = 0
>>>
>>> f = Foo()
>>> f.soemarg = 42
>>>
>>> ---^ There, typo, but still working
>>>
>>> It's something like a custom __setattr__ that errors out when trying 
>>> to assign to an attribute that doesn't exists,
>>
>> Chicken and egg problem, really :  f.__dict__['somearg'] doesn't 
>> exists until "self.somearg = 0" is executed.
>>
>> The "problem" is that Python's methods are only thin wrapper around 
>> functions (cf http://wiki.python.org/moin/FromFunctionToMethod) so 
>> there's no difference between "self.somearg = 0" in Foo.__init__ and 
>> "f.somearg = 42".
>>
>> IOW, there's no way to implement this proposal without completely 
>> changing Python's object model.
> 
> I must be missing something. Can you please explain why the whole object 
> model would need to change?

UHHM! Forget it. This of course doesn't work with setattr too. My 
stupidness. :-(