[Python-ideas] Enhancing vars()

[Emanuel Barry]

> From Steven D'Aprano
> Sent: Tuesday, December 13, 2016 6:49 PM
> To: python-ideas at python.org
> Subject: Re: [Python-ideas] Enhancing vars()
> 
> But if the object has __slots__, with or without a __dict__, then vars
> should return a proxy which direct reads and writes to the correct slot
> or dict.
> 
> It might be helpful to have a slotsproxy object which provides a
> dict-like interface to an object with __slots__ but no __dict__, and
> build support for both __slots__ and a __dict__ on top of that.

That might be a bit tricky, for example, it's possible that a class has a
`foo` slot *and* a `foo` instance attribute (by virtue of subclasses). What
would you do in that case? Or what if there's a slot that doesn't have any
value (i.e. raises AttributeError on access, but exists on the class
nonetheless), but an instance attribute with the same name exists? And so
on.

> If the objects has *neither* __slots__ nor __dict__, vars can probably
> raise a TypeError.

Is that even possible in pure Python? The only object I know that can do
this is `object`, but some other C objects might do that too.

-Emanuel