On Fri, Sep 27, 2019 at 11:18 AM Serhiy Storchaka <storchaka@gmail.com> wrote:

I think it needs an explicit support in the type creation machinery (as
__slots__ itself has) to support descriptors and slots with the same name.

That would be tough, since __slots__ is currently implemented by creating a separate descriptor for each slot.

I do think that it would be nice to have a way to automatically create __slots__ from annotations. It would be even nicer if that could be done without copying the class object (as the current state of the art requires: https://github.com/ericvsmith/dataclasses/blob/master/dataclass_tools.py#L23).

Thinking aloud, perhaps this could be done by setting __slots__ to a magical value, e.g.

class Point:

    __slots__ = "__auto__"

    x: float

    y: float

This would be independent from the @dataclass decorator (though the decorator may have to be aware of the magic value).

If that's too wacky, we could also use a class keyword argument:

class Point(slots=True):

    x: float

    y: float

(Though arguably that's just as wacky. :-)