On Wed, Jul 3, 2013 at 1:55 PM, Ron Adam <ron3200@gmail.com> wrote:

On 07/03/2013 12:34 PM, Guido van Rossum wrote:

On Wed, Jul 3, 2013 at 9:56 AM, Ron Adam <ron3200@gmail.com> wrote:

Sometimes adding a backslash within a container can make a continued line
between many single line items stand out better. (*)

(* There have been "silent" bugs where a comma was omitted in cases where
some lines are continued and some aren't.)

I don't understand what you are referring to here, but I don't think
we should invoke backslashes to solve the problem of significant
trailing commas.

I'll see if I can find some real examples of this.

It's a case where there is a long list, and every once in a while there is a long line that is implicitly continued. So an occasional missing comma is what is supposed to be there. Which makes seeing an actual missing comma is harder to do.

When there is a long list with only a few continuations, I don't see how a few backslashes would be harmful, they would explicitly show those line are meant to be continued and are not missing a comma.

I don't think this comes up that often, so it probably doesn't need any special treatment.

Maybe you're talking about this case:

instructions = [
    'foo',
    'bar',
    'very long line'            # comma intentionally missing
    ' which is continued here',
    'not so long line' # comma accidentally missing
    'accidentally continued',
    'etc.',
]

I brought this up a few weeks or months ago, hoping to convince people that implicit string concatenation is evil enough to ban. I didn't get very far.

But allowing backslashes here won't accomplish anything, because they are redundant. (In fact I get really mad when people use backslashes for continuation inside parens/brackets/braces. :-)