Python dynamic attribute creation

[Mark Lawrence]

On 28/06/2010 20:23, Alexander Kapps wrote:
> 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. :-(
>
>

Don't worry too much, looks like your nation's football is much better 
than your settattr knowledge.  I'm now setting up another charity to 
parallel the home in Dublin for blind Irish referees. [1]

Kindest regards.

Mark Lawrence

[1] google for Max Boyce Irish Referees