Why nested scope rules do not apply to inner Class?

[Calvin Spealman]

On Wed, Aug 13, 2008 at 11:32 AM, Cousson, Benoit <b-cousson at ti.com> wrote:
>> Defining it as a nested class saves you one line
>> of code, but IMHO makes the result just a bit more cluttered, while
>> reducing the elegance of reusing the metaclass.
>
> The whole point of nested class is to avoid polluting the namespace with classes that are only used locally. So the argument about the elegance of reusing is not very valid in that case.

There is no point of nested classes because nested classes _are not_
supported by python. They are simply an artifact of not actively
denying the syntax non-globally. I would fully support a change to the
language to actively forbid a class definition that is not
module-level.

> I agree that they are other ways using module to avoid namespace pollution, but in some case it is easier to use nested class instead and keep everything in the same file.

I don't consider it pollution. If you want it considered "private" to
the module, name it with an underscore.

> In my case, I'm trying to use a similar approach as XIST's one, meaning using Python class to model hierarchical data. So clearly nested class is a very nice and easy understandable way to do that.

I don't find that this is clear in anyway. I can't imagine why you'd
think a nested class is even useful here, rather than an instance with
some understandable attributes. I've seen a lot of places nested
classes are used and not one of them that should be been doing it.

But, on that note, there is a point where a discussion is obviously
not going to resolve with either side changing their minds. This is
obviously such a case.

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