Font-Locking for Allout Mode

[Tassilo Horn <tassilo@member.fsf.org>]

Hello,

I'm a new user of allout-mode and I really like it. The only thing that
has to be improved is the readability of the headings. I would like to
use font locking to adjust the faces like the AUCTeX sectioning faces.

On EmacsWiki [1] I found some snippets for doing that, although the
first one seems to be outline-mode specific. So I adapted it for allout
mode and came up with this:

,----[ ~/.emacs ]
| (defvar th-allout-font-lock-keywords
|   '(;; Highlight headings according to the level.
|     (eval . (list (concat "^\\(" allout-regexp "\\).+")
|                 0 '(or (cdr (assq (allout-depth)
|                                   '((1 . font-lock-function-name-face)
|                                     (2 . font-lock-variable-name-face)
|                                     (3 . font-lock-keyword-face)
|                                     (4 . font-lock-builtin-face)
|                                     (5 . font-lock-comment-face)
|                                     (6 . font-lock-constant-face)
|                                     (7 . font-lock-type-face)
|                                     (8 . font-lock-string-face))))
|                        font-lock-warning-face)
|                 nil t)))
|   "Additional expressions to highlight in Allout mode.")
| 
| (defun th-font-lock-allout ()
|   (interactive)
|   (font-lock-add-keywords nil th-allout-font-lock-keywords))
| 
| (add-hook 'allout-mode-hook
|           'th-font-lock-allout)
`----

But it seems to have no effect. The regexp from above is

"^\\(\\(;;;_[ 	]*[\\.,\\*\\+--=>()\\[{}&!\\?#%\"X@\\$~_\\\\:;\\^;;;_]\\)\\|\\(;;;_\\|;;;_\\)+ ?[^;;;_]\\|\f\\).+"

It is for allout mode in a emacs lisp buffer. If I enter it in
`re-builder' it matches the allout topic headings just fine.

Can anyone see what's wrong with the code?

Thanks in advance,
Tassilo

Footnotes: 
[1] http://www.emacswiki.org/cgi-bin/wiki/AllOut
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