[Python-Dev] NotImplemented reaching top-level

[Neil Schemenauer]

Armin Rigo <arigo at tunes.org> wrote:
> Of course, speaking of a rewrite, PyPy does the "right thing" in
> these two areas.  Won't happen to CPython, though.  There are too
> much backward-compatibility issues with the PyTypeObject
> structure; I think we're doomed with patching the bugs as they
> show up.

This is definitely something that should be cleaned up for Python
3k.

> Looking up in the language reference, I see no mention of NotImplemented
> in the page about __add__, __radd__, etc.  I guess it's a documentation
> bug as well, isn't it?  The current code base tries to implement the
> following behavior: Returning NotImplemented from any of the binary
> special methods (__xxx__, __rxxx__, __ixxx__) makes Python proceed as if
> the method was not defined in the first place.
>
> If we agree on this, I could propose a doc fix, a test, and appropriate
> bug fixes.

I believe that's correct.

  Neil