font lock problem in C mode

font lock problem in C mode

[Stephen Eglen]

Put the following C comment into a file, called e.g. "s.c"

/**
 * Simple comment.
 */

and then do:

$emacs -q s2.c

The comment is fontified as a "string", rather than a "comment".  If I
delete the 2nd asterisk on the first line, the font switches correctly
to be fontified as a comment.


Stephen



In GNU Emacs 22.1.1 (i686-pc-linux-gnu, X toolkit)
 of 2007-06-03 on notch.damtp.cam.ac.uk
Windowing system distributor `The XFree86 Project, Inc', version 11.0.40300000
configured using `configure  '--prefix=/home/raid/bio/sje30/NOBACKUP/local''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: C
  locale-coding-system: nil
  default-enable-multibyte-characters: t

Major mode: C/l

Minor modes in effect:
  tooltip-mode: t
  tool-bar-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  auto-compression-mode: t
  line-number-mode: t
  abbrev-mode: t

Recent input:
<right> C-e <left> C-d C-x u C-x C-s M-x r e p o r 
t SPC e m SPC b SPC <return>

Recent messages:
("emacs" "-q" "s2.c")
For information about the GNU Project and its goals, type C-h C-p.
Loading cc-mode...done
For information about the GNU Project and its goals, type C-h C-p.
Undo!
(No changes need to be saved)
Loading emacsbug...done

Re: font lock problem in C mode

[martin rudalics]

 > Put the following C comment into a file, called e.g. "s.c"
 >
 > /**
 >  * Simple comment.
 >  */
 >
 > and then do:
 >
 > $emacs -q s2.c
 >
 > The comment is fontified as a "string", rather than a "comment".

It is fontified as a "doc-string" (if you customize `font-lock-doc-face'
you will see the difference).

 > If I
 > delete the 2nd asterisk on the first line, the font switches correctly
 > to be fontified as a comment.

It is a "feature".  Alan Mackenzie will explain this carefully and in
full detail ... Alan, good evening, it's me again ;-)

Re: font lock problem in C mode

[Jason Rumney]

martin rudalics wrote:
> It is fontified as a "doc-string" (if you customize `font-lock-doc-face'
> you will see the difference).

Is there a good reason why it only works with javadoc style comments,
and not other commonly used documentation comment indicators?

ie doxygen also recognizes Qt style, C# style and a hybrid style:

 /*!
  * documentation
  */

/// documentation

//! documentation

Re: font lock problem in C mode

[Alan Mackenzie]

Hi, Stephen, Hi, Martin!

Stephen, your address wouldn't be "Department of Applied Mathematics and
Theoretical Physics", by any chance?

On Fri, Jun 15, 2007 at 10:27:02PM +0200, martin rudalics wrote:
>  > Put the following C comment into a file, called e.g. "s.c"
>  >
>  > /**
>  >  * Simple comment.
>  >  */
>  >
>  > and then do:
>  >
>  > $emacs -q s2.c
>  >
>  > The comment is fontified as a "string", rather than a "comment".

> It is fontified as a "doc-string" (if you customize `font-lock-doc-face'
> you will see the difference).

>  > If I delete the 2nd asterisk on the first line, the font switches
>  > correctly to be fontified as a comment.

> It is a "feature".  Alan Mackenzie will explain this carefully and in
> full detail ... Alan, good evening, it's me again ;-)

OK, OK, OK!

The feature is in CC Mode what a doc-string is in Emacs Lisp.  It's
documented in the (new) CC Mode manual on page "Doc Comments".  The
default in C Mode is "gtkdoc", the documentation convention used by
Gnomes.

If you don't like it (and I realise here that having an unwanted feature
thrust upon one is far worse than the lack of wanted one), disable it by
setting c-doc-comment-style to nil.  This is a CC Mode "style variable",
with all the facilities and hassle that come with these.  Basically, set
it to nil AS EARLY AS POSSIBLE in your .emacs (or use the customize-..
facilities), as described on the manual page "Config Basics".

-- 
Alan Mackenzie (Ittersbach, Germany).

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