A derived mode for OTT.

ott-mode.el

;; ott-mode.el -- A Derived mode for writing OTT files
;;
;;; DESCRIPTION
;;
;; A derived mode to highlight OTT input files.
;;
;;; INSTALLATION
;;
;; 1. Place ott-mode.el in your .emacs.d directory
;; 2. Ensure that .emacs.d is on your load path.
;; 3. Add the following to your emacs setup file:
;;    (require 'ott-mode)
;;    (add-to-list 'auto-mode-alist (quote ("\\.ott$" . ott-mode)))
;;    or augment your setup accordingly.
;; -------------------------------------------------------------------
;;; CODE
(defvar ott-keywords '(
    "metavar" "indexvar" "grammar" "embed" "subrules" "contextrules"
    "substitutions" "single" "multiple" "freevars" "defns" "defn"
    "by" "homs" "funs" "fun" "parsing" "begincoqsection"
    "endcoqsection" "coqvariable" "left" "right" "terminals"
    "formula" "judgement"
))
;; -------------------------------------------------- [ Assign Faces ]
(defvar ott-font-lock-defaults
  `((
    ( ,(regexp-opt ott-keywords     'words) . font-lock-keyword-face)    
    ( "(\\+.+\\+)\\|-->\\|{{\\|}}\\|;\\|<::\\|_::\\|::=\\|::\\|<=\\|<<.*\\|>>\\|</\\|//\\|/>\\|\|" . font-lock-constant-face)
)))
;; --------------------------------------------------- [ Clear memory ]
(setq ott-keywords     nil
)
;; -------------------------------------------------------------------
;; SIF Definition
;; -------------------------------------------------------------------
(define-derived-mode ott-mode fundamental-mode "OTT"
  "Major mode for editing OTT files."
  (defgroup ott-mode nil
    "Derived mode for OTT Files" :group 'languages)
  (defvar ott-mode-hook nil "Hook for ott-mode")
    (modify-syntax-entry ?%  "<" ott-mode-syntax-table)
    (modify-syntax-entry ?\n ">" ott-mode-syntax-table)

  ;; (mapcar (lambda (x)
  ;;           (modify-syntax-entry x "_" ott-mode-syntax-table))
  ;;         ;; Some of these are actually OK by default.
  ;;         "!#$%&*+./:<=>?@^|~")


  (make-local-variable 'ott-font-lock-defaults)
  (make-local-variable 'comment-start)
  (make-local-variable 'comment-end)
  (make-local-variable 'comment-start-skip)
  (make-local-variable 'comment-column)
  (make-local-variable 'comment-padding)
  (make-local-variable 'comment-multi-line)
  (make-local-variable 'comment-indent-function)

  (setq font-lock-defaults ott-font-lock-defaults
        comment-start           "% "
        comment-end             ""
        comment-start-skip      "+ %+ \n"
        comment-column          60
        comment-padding         0
        comment-multi-line      nil
        comment-indent-function 'java-comment-indent
        indent-tabs-mode        t
  )
 (run-hooks 'ott-mode-hook)
)

(provide 'ott-mode)

Multi-line comments and inserts i.e. between {{ }} are not properly handled. There is trouble getting the regex for comment-start-skip and comment-end-skip to recognise comments.