[Python-Dev] conditional expressions - add parens? (original) (raw)

Jim Jewett jimjjewett at gmail.com
Mon Mar 6 21:15:30 CET 2006

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 "absoluteimport" 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 "absoluteimport" 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

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