[Python-Dev] conditional expressions - add parens?

[Jim Jewett]

On 3/6/06, Thomas Wouters <thomas at python.org> wrote:
> On 3/6/06, Jim Jewett <jimjjewett at gmail.com> wrote:

> >     level = 0 if "absolute_import" in self.futures else -1

> > Mentally, I can't help parsing that as "level = 0" plus
> > comments that turn out to be code that triggers
> > backtracking.

> > I think that adding parentheses would help ...

> >     level = (0 if "absolute_import" in self.futures else -1)

> I'm not sure, are you suggesting the grammar/parser
> enforces it that way, or that it should be in PEP-8?

I would prefer that the grammar enforce it, but putting
it in PEP 8 would be a half-way measure.

I can't imagine an expression small enough that the
parentheses really hurt.

    var = t if c else f
    var = (t if c else f)

In PEP 8, I would even go so far as to recommend
parentheses around the three sub-expressions if
they contain any internal whitespace, but I don't
think the grammar should enforce that.

> (I still can't help but go 'yecchh' whenever I see the
> code. It looks like Perl's 'expr if expr' form, but it
> behaves quite different. Right now, removing if/else
> expressions still looks like the best solution, to me :->

Yah, that sounds uncontroversial.  :D

-jJ