[Python-ideas] allow line break at operators

[Devin Jeanpierre]

> Right now you do not need to indent continuation lines. So in order to disambiguate you would need to enforce indentation for continuations, but for backward compatibility that would only be required when not using parentheses or backslashes. Ick. Can blank lines or comment lines appear between a line and its continuation? That's allowed now as well.

Eek no. If I was suggesting anything, it would have been a third form
of continuation: collapsing subsequent extra-indented lines. This is
never ambiguous. (This could be done in such a way as to permit
comments, namely, by doing it to the tokenstream rather than to the
actual text)

Devin

On Thu, Aug 11, 2011 at 4:45 PM, Bruce Leban <bruce at leapyear.org> wrote:
>
> On Thu, Aug 11, 2011 at 12:24 PM, Devin Jeanpierre <jeanpierreda at gmail.com> wrote:
>>
>> Javascript also lets you break lines. For example, this does what you want:
>>
>>     return 1
>>         + 5
>>
>> Whereas this does not
>>
>>     return
>>         1 + 5
>>
>> Of course, Python would have no such problem, because you could make both cases unambiguous due to the indent.
>>
>> Devin
>>
> Note that this is already valid and is not a continuation line:
>
> return 1
> +5
>
> Right now you do not need to indent continuation lines. So in order to disambiguate you would need to enforce indentation for continuations, but for backward compatibility that would only be required when not using parentheses or backslashes. Ick. Can blank lines or comment lines appear between a line and its continuation? That's allowed now as well.
> Now allowing line breaks *after* operators would be unambiguous and would not require new indentation rules. When a line ends with an operator, it's clearly incomplete (so no fear the reader will think the statement has ended unlike the above case) and it's a syntax error today:
>
> return 1 +
>     5
> x = y > 0 and
>    y < 10
>
> This code is not valid today without parens or \ regardless of indentation. I'm +0 on this. I'd use it but does it really add enough convenience?
> --- Bruce
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