[Python-ideas] Adding rule about trailing comma.

[INADA Naoki]

On Tue, Mar 31, 2015 at 4:30 PM, Andrew Barnert <abarnert at yahoo.com> wrote:
> On Mar 30, 2015, at 23:35, INADA Naoki <songofacandy at gmail.com> wrote:
>>
>> What about adding rule about trailing comma?
>
> I don't understand the proposed rule from your example. Are you suggesting that a trailing comma be a syntax error unless it's following by a newline?

I'm sorry, I meant about adding rule to PEP 8. Not Python syntax.

> That would explain both "yesses" and the first "no", but then what's wrong with the second "no"? You can always add newlines in the middle of any parenthesized expression; are you suggesting that you shouldn't be allowed to add one at the very end, unless it's immediately following a comma? If so, why?
>
> Also, you seem to realize you're adding a gratuitous inconsistency with one-element tuples. Haven't they been through enough teasing without having to make them even more different?
>
> Most of all, whatever your actual rule is: Why? What's the intended benefit here?

I recently write Go program more than Python.
I feel good about line continuation rule in Go: Some characters
including comma means line continuation.

Benefit of this style is:

1) More consistent
2) No garbage diff just for just adding comma

>
>>
>> Yes:
>>
>> foo(aaa,
>>    bbb)
>>
>> or
>>
>> foo(aaa,
>>    bbb,
>> )
>>
>> No:
>>
>> foo(aaa,
>>    bbb,)  # except one-value tuple.
>>
>> or
>>
>> foo(aaa,
>>    bbb
>> )
>>
>>
>>
>> --
>> INADA Naoki  <songofacandy at gmail.com>
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-- 
INADA Naoki  <songofacandy at gmail.com>