[Python-ideas] Non-boolean return from __contains__

[Alexander Belopolsky]

On Mon, Jul 26, 2010 at 12:09 PM, Ian Bicking <ianb at colorstudy.com> wrote:
..
> I know overriding "and" and "or" has been discussed some time ago, though
> I'm not sure what the exact reason is that it never went anywhere.

Indeed.  See PEP 335. http://www.python.org/dev/peps/pep-0335/.

> I remember it as one of those epic-and-boring comp.lang.python threads ;)  One
> obvious complication is that they are short-circuit operations.  That is, "a
> and b" must evaluate a, figure out if it is false, and if so then it returns
> a.  But "a or b" must evaluate a, figure out if it is TRUE, and if so then
> returns a.  So if there was anything like __and__ and __or__ it would have
> to simply disable any short-circuiting.

The PEP deals with short-circuiting AFAIK.