On 4 сент, 21:49, Bruno Desthuilliers
<[EMAIL PROTECTED]> wrote:
> Ivan Illarionov a écrit :
>
>
>
> > On 4 сент, 22:59, Carl Banks <[EMAIL PROTECTED]> wrote:
> >> You can write code to guard against this if you want:
>
> >> class A:
> >> legal = set(["x"])
> >> def __setattr__(self,attr,val):
> >> if attr not in self.legal:
> >> raise AttributeError("A object has no attribute '%s'" %
> >> attr)
> >> self.__dict__[attr] = val
> >> def __init__(self,x):
> >> self.y = x
>
> >> I suspect most people who go into Python doing something like this
> >> soon abandon it when they see how rarely it actually catches anything.
>
> > '__slots__' is better:
>
> For which definition of "better" ? __slots__ are a mean to optimize
> memory usage, not to restrict dynamism. Being able to dynamically add
> arbitrary attributes is actually a feature, not a bug, and uselessly
> restricting users from doing so is not pythonic. IOW : don't do that.
Carl's example is restricting dynamism in the same way as __slots__.
I've just suggested a better implementation. It is not me who
suggested dynamism restriction as a way to guard against errors.
--
http://mail.python.org/mailman/listinfo/python-list
