In <[EMAIL PROTECTED]>, Timo wrote:
> Steve Jobless kirjoitti:
>
>> Let's say the class is defined as:
>>
>> class MyClass:
>> def __init__(self):
>> pass
>> def func(self):
>> return 123
>>
>> But from the outside of the class my interpreter let me do:
>>
>> x = MyClass()
>> x.instance_var_not_defined_in_the_class = 456
>>
>> or even:
>>
>> x.func = 789
>>
>> After "x.func = 789", the function is totally shot.
>>
>
> You can avoid the problem by using the __slots__ definition and
> new-style classes (inherit from object):
>
> class MyClass(object):
>
> __slots__ = ('bar',)
>
> def func(self):
> return 123
>
> x = MyClass()
> x.instance_var_not_defined_in_the_class = 456
> ==>
> AttributeError: 'MyClass' object has no attribute
> 'instance_var_not_defined_in_the_class'
>
> x.func = 789
> ==>
> AttributeError: 'MyClass' object attribute 'func' is read-only
>
> Only the bar-attribute can be set:
>
> x.bar = 'foo'
This avoids the problem but you get others in return. And it's an abuse
of `__slots__` which is meant as a way to save memory if you need really
many objects of that type and not as "protection".
Ciao,
Marc 'BlackJack' Rintsch
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