Title:		Creating an Ox-major mode in Emacs.
Author:		Michael Höhle <hoehle@dina.kvl.dk>
Date:		18 December 2000
Category:	Quick (and Dirty) Hacks.

An easy way to get highlighting and indentation of Ox files in Emacs
20.5 is to use C++-mode. The biggest prohibiting problem (in my eyes)
is the use of "'" in Ox to invert matrices. This totally messes up
hi-lighting etc. What needs to be done is to change the meaning of ?\'
in the syntax-table when working with Ox files. A quick (and dirty?)
way to achieve this is to add an ox-mode into the cc-mode files which
more or less steal everything from the c++ mode - except the
syntax-table. Hi-lighting for the Ox specific keywords is obtained by
adding support for the ox-mode to font-lock.el. To achieve the above
solution, proceed as follows.

Make a backup of the files
     $EMACS/lisp/progmodes/cc-langs.el and
     $EMACS/lisp/progmodes/cc-mode.el  
     $EMACS/lisp/font-lock.el

After this security announcement proceed by adding the following to
$EMACS/lisp/progmodes/cc-langs.el just before the line "(provide
'cc-langs)".

;
;  Support for Ox
;
; (added by Michael Höhle <hoehle@dina.kvl.dk>, 18 December 2000)
;;;###autoload
(defvar ox-mode-syntax-table nil
  "Syntax table used in ox-mode buffers.")
(if ox-mode-syntax-table
    ()
  (setq ox-mode-syntax-table (make-syntax-table))
  (c-populate-syntax-table ox-mode-syntax-table)
  ; Unfortunately in Ox \' means transposing a matrix
  ; If nothing done hi-lights are not proper, so we change its meaning to word
  (modify-syntax-entry ?\' "w" ox-mode-syntax-table)
  )

In $EMACS/lisp/progmodes/cc-mode.el just before the line ";; bug
reporting" add

;;;###autoload
(defun ox-mode ()
  "Major mode for editing Ox code.
Added to CC-mode by Michael Höhle <hoehle@dina.kvl.dk>, 18 December 2000

To see what version of CC Mode you are running, enter `\\[c-version]'.

The hook variable `ox-mode-hook' is run with no args, if that
variable is bound and has a non-nil value.  Also the hook
`c-mode-common-hook' is run first.

Key bindings:
\\{c++-mode-map}"
  (interactive)
  (c-initialize-cc-mode)
  (kill-all-local-variables)
  ; This is the only change - we use an ox-mode-syntax-table to
  ; correct for ' problem.
  (set-syntax-table ox-mode-syntax-table)
  (setq major-mode 'ox-mode
	mode-name "Ox"
	local-abbrev-table c++-mode-abbrev-table)
  (use-local-map c++-mode-map)
  (c-common-init)
  (setq comment-start "// "
	comment-end ""
	c-conditional-key c-C++-conditional-key
	c-comment-start-regexp c-C++-comment-start-regexp
	c-class-key c-C++-class-key
	c-extra-toplevel-key c-C++-extra-toplevel-key
	c-access-key c-C++-access-key
	c-recognize-knr-p nil
	imenu-generic-expression cc-imenu-c++-generic-expression
	imenu-case-fold-search nil
	)
  (run-hooks 'c-mode-common-hook)
  ; Better run the ox-hooks instead of c++-mode-hook
  (run-hooks 'ox-mode-hook)
  (c-update-modeline))

This is quick and dirty and reuses most of the c++-part. Only thing
left is to make font-lock.el aware of the ox-mode and have it hi-light
ox specific keywords. Replace font-lock.el file with the one found at
http://www.dina.kvl.dk/~hoehle/software/ox/font-lock.el.  

To make everything work it is necessary to byte-compile the three
edited files (cc-mode.el, cc-lang.el, font-lock.el), e.g. with Esc-x
byte-compile-file. Now all there is left is to edit your ~/.emacs file
to auto-load ox-mode on files with the ".ox" extension.

(require 'cc-mode) ; necessary to put it here in order to get extra modes.
(setq auto-mode-alist
      (append '(("\\.ox$"   . ox-mode)
                ) auto-mode-alist))

If you want to be able to run Ox within Emacs you might consider adding the 
following to your .emacs file. It makes C-c o execute the current buffer 
(requires oxl to be in your current path). [Suggested by Riccardo `Jack' 
Lucchetti <jack@deanovell.unian.it>]

(defun ox-compile ()
	  "Try and compile an ox file"
	  (interactive ())
	  (save-buffer) (shell-command (concat "oxl " (buffer-file-name) ) nil nil ))

(setq ox-mode-map nil)
(add-hook 'ox-mode-hook
	'(lambda ()
		(local-set-key
			"\C-co"
			'ox-compile)
	))

Restart emacs and enjoy (with the usual disclaimer: use is at own risk)!