bug#60034: comment character for org and python includes a space

bug#60034: comment character for org and python includes a space

[Heime via Bug reports for GNU Emacs, the Swiss army knife of text editors]

How is it that the comment character for org and python include a space "# ", when
for all other languages it is only a single character?

bug#60034: comment character for org and python includes a space

[Stefan Kangas]

tags 60034 + moreinfo
thanks

Heime via "Bug reports for GNU Emacs, the Swiss army knife of text
editors" <bug-gnu-emacs@gnu.org> writes:

> How is it that the comment character for org and python include a space "# ", when
> for all other languages it is only a single character?

Could you explain which variable(s) you are looking at?

Are you reporting a bug in the behavior of python-mode and org-mode?  If
so, what is it?

bug#60034: comment character for org and python includes a space

[Heime via Bug reports for GNU Emacs, the Swiss army knife of text editors]

------- Original Message -------
On Tuesday, December 13th, 2022 at 6:36 PM, Stefan Kangas <stefankangas@gmail.com> wrote:


> tags 60034 + moreinfo
> thanks
> 
> Heime via "Bug reports for GNU Emacs, the Swiss army knife of text
> editors" bug-gnu-emacs@gnu.org writes:
> 
> > How is it that the comment character for org and python include a space "# ", when
> > for all other languages it is only a single character?
> 
> 
> Could you explain which variable(s) you are looking at?
> 
> Are you reporting a bug in the behavior of python-mode and org-mode? If
> so, what is it?

It is about "comment-start".  I am constructing a "regexp" for use with hi-lock mode to highlight certain comments.

For elisp I am matching ";; [Text] More"

The regex is adapted for the particular programming mode.  Another difficulty has been that in "c-mode", "comment-start" returns "/*" with no possibility to get the alternative "//". 

(defun tegor ()
  "TODO."
  (interactive)

  (let ( (fm (format "%s%s" comment-start comment-start)) )

    (message "fm: %s" fm)
    (message "kmcategor: %s"
       (format "%s%s%s" "^\s*" fm "\s\\(\\[.+\\]\\).*$"))))

bug#60034: comment character for org and python includes a space

[Stefan Kangas]

Heime <heimeborgia@protonmail.com> writes:

>> Heime via "Bug reports for GNU Emacs, the Swiss army knife of text
>> editors" bug-gnu-emacs@gnu.org writes:
>>
>> > How is it that the comment character for org and python include a
>> > space "# ", when for all other languages it is only a single
>> > character?
>>
>> Could you explain which variable(s) you are looking at?
>>
>> Are you reporting a bug in the behavior of python-mode and org-mode?
>> If so, what is it?
>
> It is about "comment-start".  I am constructing a "regexp" for use
> with hi-lock mode to highlight certain comments.
>
> For elisp I am matching ";; [Text] More"
>
> The regex is adapted for the particular programming mode.

It seems like we do it both ways in our sources, so I'm not sure if it
matters, or what is the correct way.  It's not documented in the
`comment-start' docstring either.

Perhaps it's better to just leave it out unless it is a part of the
language grammar, but I don't know if it would have any adverse effects.

Stefan, what do you think?

> Another difficulty has been that in "c-mode", "comment-start" returns
> "/*" with no possibility to get the alternative "//".

Please report this as a separate bug report, and include the use case
you're looking at with all the details.

> (defun tegor ()
>   "TODO."  (interactive)
>   (let ( (fm (format "%s%s" comment-start comment-start)) )
>     (message "fm: %s" fm) (message "kmcategor: %s"
>        (format "%s%s%s" "^\s*" fm "\s\\(\\[.+\\]\\).*$"))))

bug#60034: comment character for org and python includes a space

[Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors]

>>> > How is it that the comment character for org and python include a
>>> > space "# ", when for all other languages it is only a single
>>> > character?

FWIW, both options are valid and they lead to different results
when you do `M-;` (as well as as when `-comment-add` is 0).

E.g. ELisp uses ";" rather than "; " so that you can do `M-; ; hello` to
add a comment of the form `;; hello` at the end of the current line.

In modes where using repetitions of the comment char is unusual
(typically because indentation rules don't pay attention to the number
of consecutive comment chars), it's more common to add a space at the
end of `comment-start`.


        Stefan

bug#60034: comment character for org and python includes a space

[Stefan Kangas]

tags 60034 + notabug wontfix
close 60034
thanks

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>>>> > How is it that the comment character for org and python include a
>>>> > space "# ", when for all other languages it is only a single
>>>> > character?
>
> FWIW, both options are valid and they lead to different results
> when you do `M-;` (as well as as when `-comment-add` is 0).
>
> E.g. ELisp uses ";" rather than "; " so that you can do `M-; ; hello` to
> add a comment of the form `;; hello` at the end of the current line.
>
> In modes where using repetitions of the comment char is unusual
> (typically because indentation rules don't pay attention to the number
> of consecutive comment chars), it's more common to add a space at the
> end of `comment-start`.

Thanks, so I don't think there's anything to fix here.  If someone needs
the space-free version, they can use something like:

    (string-remove-suffix " " comment-start)

So I'm closing this as a wontfix.  Sorry.