if, continuation and indentation

[john]

On May 28, 10:37 am, "Colin J. Williams" <cjwilliam... at gmail.com>
wrote:
> On 28-May-10 05:54 AM, Jonathan Hartley wrote:
>
> > On May 27, 1:57 pm, Jean-Michel Pichavant<jeanmic... at sequans.com>
> > wrote:
> >> HH wrote:
> >>> I have a question about best practices when it comes to line wrapping/
> >>> continuation and indentation, specifically in the case of an if
> >>> statement.
>
> >>> When I write an if statement with many conditions, I prefer to use a
> >>> parenthesis around the whole block and get the implicit continuation,
> >>> rather than ending each line with an escape character.  Thus, using
> >>> the example from the style guide (http://www.python.org/dev/peps/
> >>> pep-0008/) I would write:
>
> >>>      if (width == 0 and
> >>>          height == 0 and
> >>>          color == 'red' and
> >>>          emphasis == 'strong' or
> >>>          highlight>  100):
> >>>          raise ValueError("sorry, you lose")
>
> >>> The problem should be obvious -- it's not easy to see where the
> >>> conditional ends and the statement begins since they have the same
> >>> indentation.  Part of the problem, I suppose, is that Emacs indents
> >>> 'height' and the other lines in the conditional to 4 spaces (because
> >>> of the parenthesis).  How do people deal with this situation?
>
> >>> Thanks,
> >>> Henrik
>
> >> One possible solution
>
> >>      if (
> >>              width == 0 and
> >>              height == 0 and
> >>              color == 'red' and
> >>              emphasis == 'strong' or
> >>              highlight>  100
> >>         ):
> >>          raise ValueError("sorry, you lose")
>
> >> JM
>
> > I've always liked this, or even:
>
> >    if (
> >        width == 0 and
> >        height == 0 and
> >        color == 'red' and
> >        emphasis == 'strong' or
> >        highlight>  100
> >    ):
> >        raise ValueError("sorry, you lose")
>
> > but my co-workers have uniformly gone bananas whenever I try it.
>
> I liked:
>
> On 27-May-10 08:48 AM, Xavier Ho wrote:
>  > On 27 May 2010 22:22, HH <henri... at gmail.com > <mailto:henri... at gmail.com>> wrote:
>
>  >
>  >         if (width == 0 and
>  >             height == 0 and
>  >             color == 'red' and
>  >             emphasis == 'strong' or
>  >             highlight > 100):
>  >             raise ValueError("sorry, you lose")
>  >
>  >
>  > I've gotta say - I've bumped into this problem before, and I'm sure many
>  > other have - this is a valid question. It just hasn't bothered me enough
>  > to ask...
>  >
>  > Correct me if I'm wrong, but I think the following is equivalent, and
>  > looks better. Although this won't fix all ugly cases in that problem..
>  >
>  > if (width, height, color, emphasis) == (0, 0, 'red', 'strong') or
>  > highlight > 100:
>  >      raise ValueError("sorry, you lose")
>  >
>  > Cheers,
>  > Xav
>
> but nobody commented.
>
> Colin W.

Colin:
Sure, you can do it that way.  IMO, though, the OP was  wrong, and so
is the PEP.  Source code is meant to communicate.  So it must transmit
the correct information to the computer; it also must inform your
coworkers.  That means that you have a responsibility to care what
they think, though you privately have your opinions.  Another reason
the PEP is faulty in this circumstance is that a misplaced backslash,
or a missing one, is easily found and fixed.  A misplaced parentheses,
or just one of a pair, will transform your source code into something
which may compile and then give faulty results:  a disaster.
So keep it simple, and make it legible.
Yours,
John