Adding keywords for font-lock experts

Adding keywords for font-lock experts

[Sébastien Vauban]

Hello,

This question has already been answered several times, but never in a fully
satisfactory way. So, I ask it now, once again, but in a much more detailed
way.

My goal is to highlight some words in (almost) all modes.

As an example, I would like to see the word `Warning' highlighted in the
following buffers:

    o   any text buffer or programming buffer,
    o   the Gnus article buffer (`gnus-article-mode'),
    o   the LaTeX log buffer (`fundamental-mode'?).

To do such a thing, I've found on the Web 3 slightly different solutions,
displayed below:

--8<---------------cut here---------------start------------->8---
(make-face 'special-words)
(set-face-attribute 'special-words nil :foreground "White" :background "Firebrick")

;; solution 1
(dolist (mode '(fundamental-mode gnus-article-mode org-mode shell-mode muse-mode))
  (font-lock-add-keywords mode
                          '(("\\<\\(BUGS\\|FIXME\\|TODO\\)"
                             0 'font-lock-warning-face t)
                            ("\\<\\(Firefox\\|Warning\\|WARNING\\)"
                             0 'special-words t))))


;; solution 2
(defun highlighting-install ()
  (interactive)
  (font-lock-mode -1)
  (font-lock-mode 1)
  (font-lock-add-keywords nil
   `(("\\(BUGS\\|FIXME\\|Firefox\\|TODO\\|Warning\\|WARNING\\)"
     (1 'font-lock-warning-face prepend)))))
(dolist (hook '(fundamental-mode-hook
                gnus-article-mode-hook
                org-mode-hook
                shell-mode-hook
                muse-mode-hook))
  (add-hook hook 'highlighting-install))


;; solution 3
(let ((pattern "\\<\\(BUGS\\|FIXME\\|Firefox\\|TODO\\|Warning\\|WARNING\\)"))
  (mapc
   (lambda (mode)
     (font-lock-add-keywords mode `((,pattern 1 'special-words prepend))))
      '(fundamental-mode gnus-article-mode org-mode shell-mode muse-mode)))
--8<---------------cut here---------------end--------------->8---

They almost behave the same from a user perspective, but is one of them
superior to the others from a technical perspective (better coding regarding
different versions of Emacs, portability, etc.)?

Though, I have 2 problems:

    o   solution 2 is different from solutions 1 and 3 for the Gnus article
        buffer:

            -   in solution 2, the word `Warning' is highlighted but the rest
                of the buffer isn't anymore (mail headers);

            -   with solutions 1 and 3, the article buffer is highlighted like
                always, but the word `Warning' is not.

    o   none of the solutions highlights the word `Warning' in the LaTeX log
        (`C-c C-c LaTeX' from AUCTeX), though I've included `fundamental-mode'
        in the above codes.

Can someone help me/us getting this working?  Thanks a lot in advance!

Best regards,
  Seb

-- 
Sébastien Vauban

Re: Adding keywords for font-lock experts

[Sébastien Vauban]

Hello,

> My goal is to highlight some words [like `Warning'] in (almost) all modes.
>
> To do such a thing, I've found on the Web [...] different solutions.
>
>   (font-lock-add-keywords nil
>    `(("\\(BUGS\\|FIXME\\|Firefox\\|TODO\\|Warning\\|WARNING\\)"
>      1 'font-lock-warning-face prepend))))
>
>   [...]
>
>   (font-lock-add-keywords mode
>     `((,pattern
>       1 'special-words prepend))))
>
> They almost behave the same from a user perspective, but is one of them
> superior to the others from a technical perspective (better coding regarding
> different versions of Emacs, portability, etc.)?

I've found good documentation
(http://www.gnu.org/software/emacs/elisp/html_node/Customizing-Keywords.html#Customizing-Keywords)
explaining the differences between the exposed solutions:

    o   one is to add fontification patterns for _one major mode only_;

    o   the other affects _all derived modes_ as well.

I've now rewritten the codes as follows:

--8<---------------cut here---------------start------------->8---
;; special words
(setq keywords-level-1-pattern "\\(BUGS\\|FIXME\\|TODO\\)")
(make-face 'keywords-level-1)
(set-face-attribute 'keywords-level-1 nil :foreground "red")

(setq keywords-level-2-pattern "\\(WARNING\\)")
(make-face 'keywords-level-2)
(set-face-attribute 'keywords-level-2 nil :foreground "purple")

;; set up highlighting of special words for proper selected major modes only
(dolist (mode '(fundamental-mode
                gnus-article-mode
                message-mode
                text-mode))  ; no interference with org-mode (which derives
                             ; from text-mode)
  (font-lock-add-keywords mode
    `((,keywords-level-1-pattern 1 'keywords-level-1 prepend)
      (,keywords-level-2-pattern 1 'keywords-level-2 prepend))))
--8<---------------cut here---------------end--------------->8---

Though:

    o   it still does not work with _LaTeX logs_ (generated on the fly in
        buffers that are *not* associated with a file), such as `*test output'
        -- whose major mode is `fundamental-mode';

    o   it still does not work with Gnus (for messages that I'm _reading_ as
        well as for messages that I'm _composing_).

Can some expert please help me on this? I'm now totally blocked at this
stage...

Best regards,
  Seb

-- 
Sébastien Vauban