[Python-ideas] Parenthesized Compound With Statement

[Guido van Rossum]

Clearly some people have interpreted this dogmatically as "never use
backslashes", so I think we should explicitly update the PEP with more
moderate language and an example.

On Wednesday, July 3, 2013, Barry Warsaw wrote:

> On Jul 02, 2013, at 06:37 PM, Matthew Lefavor wrote:
>
> >As you all know, Python supports a compound "with" statement to avoid the
> >necessity of nesting these statements.
> >
> >Unfortunately, I find that using this feature often leads to exceeding the
> >79-character recommendation set forward by PEP 8.
>
> Yeah, I noticed and brought this up a while ago.  I thought I filed a bug
> but
> can't find it.  It would have been closed Won't Fix anyway.
>
> As others have pointed out, you can usually rewrite such long
> with-statements
> to conform to the PEP 8 line lengths by e.g. saving the paths in a shorter
> named local variable), using Python 3.3's ExitStack, which is awesome btw,
> or
> just using backslashes.  Remember PEP 8 isn't a weapon to be wielded by a
> stern Auntie Tim Peters.
>
> As for relaxing PEP 8, well, I'm not sure what more you'd want it to say.
>  It
> currently reads:
>
>     The preferred way of wrapping long lines is by using Python's implied
>     line continuation inside parentheses, brackets and braces.  Long lines
>     can be broken over multiple lines by wrapping expressions in
>     parentheses. These should be used in preference to using a backslash
>     for line continuation.
>
> which seems about right to me.  It is preferred to use implied continuation
> over backslashes, but doesn't say "don't use backslashes".  They're not
> evil,
> just not preferred, so use them where appropriate and with good judgment.
>
> Cheers,
> -Barry
>


-- 
--Guido van Rossum (on iPad)
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