[Python-ideas] Allow parentheses to be used with "with" block

[Neil Girdhar]

Oh, hmm, I thought it would just be converting:

with_stmt: 'with' with_item (',' with_item)*  ':' suite

to

with_stmt: 'with' ('(' with_item (',' with_item)* ')' | with_item (','
with_item)*)  ':' suite

but I guess that is ambiguous for a LL(1) parser.

Well, maybe it's harder than I thought.  Someone better with grammars than
me might know a nice way around this.

Best,

Neil


On Sun, Feb 15, 2015 at 8:28 PM, Neil Girdhar <mistersheik at gmail.com> wrote:

>
>
> On Sun, Feb 15, 2015 at 7:27 PM, Terry Reedy <tjreedy at udel.edu> wrote:
>
>> On 2/15/2015 4:52 PM, Neil Girdhar wrote:
>>
>>> It's great that multiple context managers can be sent to "with":
>>>
>>> with a as b, c as d, e as f:
>>>       suite
>>>
>>> If the context mangers have a lot of text it's very hard to comply with
>>> PEP8 without resorting to "\" continuations, which are proscribed by the
>>> Google style guide.
>>>
>>
>> Untrue.  " Backslashes may still be appropriate at times. For example,
>> long, multiple with -statements cannot use implicit continuation, so
>> backslashes are acceptable:
>>
>
> Where are you looking at that?  The one I see is here:
>
> https://google-styleguide.googlecode.com/svn/trunk/pyguide.html#Line_length
>
> Explicitly says:
>
> Exceptions:
>
>    - Long import statements.
>    - URLs in comments.
>
> Do not use backslash line continuation.
>
>
>>
>> with open('/path/to/some/file/you/want/to/read') as file_1, \
>>      open('/path/to/some/file/being/written', 'w') as file_2:
>>     file_2.write(file_1.read())"
>>
>>  Other statements like import and if support enclosing their arguments in
>>> parentheses to force aligned continuations.  Can we have the same for
>>> "with"?
>>>
>>
>> No. Considered and rejected because it would not be trivial.
>>
>>
> If your argument is the amount of work, I might be able to find the time
> to do the work  *if someone will promise to review it quickly*.  I think
> it's not more than an afternoon to modify cpython.
>
>
>> --
>> Terry Jan Reedy
>>
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