PEP308: Yet another syntax proposal

[Raymond Hettinger]

> "Aahz" <aahz at pythoncraft.com>
> > I still have yet to see a clear explanation of why short-circuit is
> > necessary and therefore iif() unreasonable.
>
> It is necessary when:
> 1. One of the alternatives has a side-effect; or
> 2. one or both alternatives are time consuming; or
> 3. the validity of the alternatives depends on the outcome
>     of the test.
>
> #  Example where all three reasons apply
> data = isinstance(source, str)  ??   source.readlines()  ||
source.split()

That should have been:
          isinstance(source, file)


Raymond Hettinger