bug#29339: 27.0.50; CC-mode doesn't know about .mm and .M suffixes for Objective-C++

bug#29339: 27.0.50; CC-mode doesn't know about .mm and .M suffixes for Objective-C++

[Philipp]

GCC uses .mm or .M for Objective-C++,
cf. https://gcc.gnu.org/onlinedocs/gcc-7.2.0/gcc/Overall-Options.html.
However, neither `auto-mode-alist' nor `cc-other-file-alist' contain
these file extensions.


In GNU Emacs 27.0.50 (build 17, x86_64-pc-linux-gnu, GTK+ Version 3.10.8)
 of 2017-11-17 built on localhost
Repository revision: 345c7d9c7b84c0c03ef1d0f32e9e0f39029be44a
Windowing system distributor 'The X.Org Foundation', version 11.0.11803000
System Description:	Ubuntu 14.04.5 LTS

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Configured using:
 'configure --enable-gtk-deprecation-warnings --with-modules
 --without-pop --with-mailutils --enable-checking
 --enable-check-lisp-object-type --enable-gcc-warnings 'CFLAGS=-ggdb3
 -O0''

Configured features:
XPM JPEG TIFF GIF PNG SOUND GSETTINGS NOTIFY GNUTLS FREETYPE XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 MODULES

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
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  eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
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  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

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system-font-setting font-render-setting move-toolbar gtk x-toolkit x
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Memory information:
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bug#29339: 27.0.50; CC-mode doesn't know about .mm and .M suffixes for Objective-C++

[Alan Mackenzie]

In article <mailman.3878.1510925890.27995.bug-gnu-emacs@gnu.org> you wrote:

> GCC uses .mm or .M for Objective-C++,
> cf. https://gcc.gnu.org/onlinedocs/gcc-7.2.0/gcc/Overall-Options.html.
> However, neither `auto-mode-alist' nor `cc-other-file-alist' contain
> these file extensions.

I don't think there's an Objective-C++ mode out there in the wild.  So
what existing mode should be used for *.mm and *.M?  Is that mode a good
enough fit to be able, in good conscience, to use it for Obj-C++?

> In GNU Emacs 27.0.50 (build 17, x86_64-pc-linux-gnu, GTK+ Version 3.10.8)
>  of 2017-11-17 built on localhost
> Repository revision: 345c7d9c7b84c0c03ef1d0f32e9e0f39029be44a
> Windowing system distributor 'The X.Org Foundation', version 11.0.11803000
> System Description:     Ubuntu 14.04.5 LTS

[ .... ]

-- 
Alan Mackenzie (Nuremberg, Germany).

bug#29339: 27.0.50; CC-mode doesn't know about .mm and .M suffixes for Objective-C++

[Philipp Stephani]

[-- Attachment #1: Type: text/plain, Size: 741 bytes --]

Alan Mackenzie <acm@muc.de> schrieb am Fr., 17. Nov. 2017 um 20:00 Uhr:

> In article <mailman.3878.1510925890.27995.bug-gnu-emacs@gnu.org> you
> wrote:
>
> > GCC uses .mm or .M for Objective-C++,
> > cf. https://gcc.gnu.org/onlinedocs/gcc-7.2.0/gcc/Overall-Options.html.
> > However, neither `auto-mode-alist' nor `cc-other-file-alist' contain
> > these file extensions.
>
> I don't think there's an Objective-C++ mode out there in the wild.  So
> what existing mode should be used for *.mm and *.M?  Is that mode a good
> enough fit to be able, in good conscience, to use it for Obj-C++?
>

According to https://www.emacswiki.org/emacs/ObjectiveCMode#toc2 objc-mode
is the most appropriate mode for now, until a true objc++-mode is added.

[-- Attachment #2: Type: text/html, Size: 1336 bytes --]

bug#29339: 27.0.50; CC-mode doesn't know about .mm and .M suffixes for Objective-C++

[Alan Mackenzie]

Hello, Philipp.

On Thu, Dec 21, 2017 at 19:22:05 +0000, Philipp Stephani wrote:
> Alan Mackenzie <acm@muc.de> schrieb am Fr., 17. Nov. 2017 um 20:00 Uhr:

> > In article <mailman.3878.1510925890.27995.bug-gnu-emacs@gnu.org> you
> > wrote:

> > > GCC uses .mm or .M for Objective-C++,
> > > cf. https://gcc.gnu.org/onlinedocs/gcc-7.2.0/gcc/Overall-Options.html.
> > > However, neither `auto-mode-alist' nor `cc-other-file-alist' contain
> > > these file extensions.

> > I don't think there's an Objective-C++ mode out there in the wild.  So
> > what existing mode should be used for *.mm and *.M?  Is that mode a good
> > enough fit to be able, in good conscience, to use it for Obj-C++?


> According to https://www.emacswiki.org/emacs/ObjectiveCMode#toc2 objc-mode
> is the most appropriate mode for now, until a true objc++-mode is added.

That only answers the first question, not the second.  If we put .M and
.mm into CC Mode or auto-mode-alist in Emacs, that implies some sort of
commitment to support the language (Objective-C++).  If Objective-C Mode
already almost supports it properly, that is one thing, but if the match
is less good, it could involve a lot of work.

From what I can gather, Objective-C++ is a bit of a mixture between
Objective-C and C++, much as its name implies.  Do these individual
facets fit together (from a CC Mode point of view) without clashing too
much?  According to Wikipedia, the language is not formerly defined in
any standard.  What, then, is the language?

Do you know of anybody working on an Objective-C++ Mode?

-- 
Alan Mackenzie (Nuremberg, Germany).

bug#29339: 27.0.50; CC-mode doesn't know about .mm and .M suffixes for Objective-C++

[Glenn Morris]

Alan Mackenzie wrote:

> That only answers the first question, not the second.  If we put .M and
> .mm into CC Mode or auto-mode-alist in Emacs, that implies some sort of
> commitment to support the language (Objective-C++).  If Objective-C Mode
> already almost supports it properly, that is one thing, but if the match
> is less good, it could involve a lot of work.

8 years ago, the comment was "switching to c++-mode or objc-mode does
not give satisfactory results". I don't know if anything has changed
since. Ref: https://debbugs.gnu.org/2732

bug#2732: 23.0.91; Please add support for Objective-C++

[Lars Ingebrigtsen]

Glenn Morris <rgm@gnu.org> writes:

>> That only answers the first question, not the second.  If we put .M and
>> .mm into CC Mode or auto-mode-alist in Emacs, that implies some sort of
>> commitment to support the language (Objective-C++).  If Objective-C Mode
>> already almost supports it properly, that is one thing, but if the match
>> is less good, it could involve a lot of work.
>
> 8 years ago, the comment was "switching to c++-mode or objc-mode does
> not give satisfactory results". I don't know if anything has changed
> since. Ref: https://debbugs.gnu.org/2732

So it doesn't seem like just mapping .mm to objc-mode would give
satisfactory results, and I'm closing this bug report.

(If somebody wants to add a real mode for Objective-C++, that can, of
course, be done.)

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#2732: 23.0.91; Please add support for Objective-C++

[Philipp]

> 
> (If somebody wants to add a real mode for Objective-C++, that can, of
> course, be done.)

Then why close this bug, which tracks exactly this feature request?

bug#2732: 23.0.91; Please add support for Objective-C++

[Alan Mackenzie]

Hello, Lars.

On Thu, Jun 03, 2021 at 12:07:18 +0200, Lars Ingebrigtsen wrote:
> Glenn Morris <rgm@gnu.org> writes:

> >> That only answers the first question, not the second.  If we put .M and
> >> .mm into CC Mode or auto-mode-alist in Emacs, that implies some sort of
> >> commitment to support the language (Objective-C++).  If Objective-C Mode
> >> already almost supports it properly, that is one thing, but if the match
> >> is less good, it could involve a lot of work.

> > 8 years ago, the comment was "switching to c++-mode or objc-mode does
> > not give satisfactory results". I don't know if anything has changed
> > since. Ref: https://debbugs.gnu.org/2732

> So it doesn't seem like just mapping .mm to objc-mode would give
> satisfactory results, and I'm closing this bug report.

> (If somebody wants to add a real mode for Objective-C++, that can, of
> course, be done.)

Personally, I don't want to spend the time (and the learning effort)
coding up an Objective-C++ Mode.  If anybody else wanted to do this
(most likely as a CC Mode derived mode), which might not be very much
work, I would be prepared to answer questions, and deliver support as
usual.

> -- 
> (domestic pets only, the antidote for overdose, milk.)
>    bloggy blog: http://lars.ingebrigtsen.no

-- 
Alan Mackenzie (Nuremberg, Germany).

bug#29339: bug#2732: 23.0.91; Please add support for Objective-C++

[Lars Ingebrigtsen]

Philipp <p.stephani2@gmail.com> writes:

>> (If somebody wants to add a real mode for Objective-C++, that can, of
>> course, be done.)
>
> Then why close this bug, which tracks exactly this feature request?

Because this request was about mapping .mm to objc-mode, which wouldn't
be appropriate, and a general request "can somebody write a brand new
mode for obscure language foo?" has little value in the bug tracker --
those types of requests seldom lead to anybody writing such a mode.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#29339: bug#2732: 23.0.91; Please add support for Objective-C++

[Lars Ingebrigtsen]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Because this request was about mapping .mm to objc-mode, which wouldn't
> be appropriate, and a general request "can somebody write a brand new
> mode for obscure language foo?" has little value in the bug tracker --
> those types of requests seldom lead to anybody writing such a mode.
                ^open

(The issue is still, of course, in the issue tracker, and anybody who
wishes to can refer to it if they should wish to write this new mode.
But it's not productive for the people doing triage of the open issues to
keep staring at the issue, year after year.)

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no