;;; n3mode.el --- RDF/N3 Syntax highlighting for xemacs 
;; by Gunnar Aastrand Grimnes, email: gromgull at the domain of gmail.com


;; this is really crappy and does comment-syntax + highlighting only
;; "english" identifiers only mind you, i.e. a-z ... 
;; in theory n3 is utf8 so you can have any identifiers you like, but 
;; I doubt this works very often. 

;; Improvements are of course welcome at above address!

;; Install: 
;; As usual: 
;; copy n3mode.el to ~/.xemacs
;; add the lines: 
;;    (load "~/.xemacs/n3mode.el")
;;    (setq auto-mode-alist (cons '("\\.n3$" . n3-mode) auto-mode-alist))
;;    (add-hook 'n3-mode-hook 'turn-on-font-lock)
;;
;; to ~/.xemacs/init.el to enable when openeing n3 files 
;; 


(defvar n3-mode-hook nil
  "Normal hook run when entering N3 mode.")


(defvar n3-font-lock-keywords
  (list
   ;; comments
   '( "#[^>].*$" . font-lock-comment-face) 
   ;; URIs
   '( "<[:/a-zA-Z_~0-9\\.\\#-]+>" . font-lock-preprocessor-face)
   ;; keywords
   '( "@prefix\\| a " . font-lock-keyword-face)
   ;; prefix:
   '( "[a-zA-Z][a-zA-Z0-9]*:" . font-lock-type-face)
   ;; variables 
   '( "\\?[a-zA-Z][a-zA-Z0-9]*" . font-lock-reference-face)
   ;; numbers 
   '( "[0-9]+\\(\\.[0-9]+\\)?" . font-lock-function-name-face)
   ;; symbols
   '( "{\\|}\\|\(\\|\)" . font-lock-function-name-face)
   ) "Additional expressions to highlight in Python mode." )

(put 'n3-mode 'font-lock-defaults '(n3-font-lock-keywords))


(defun n3-mode ()
  "Major mode for editing RDF/N3 Files."
  (interactive)
  (kill-all-local-variables)
  (make-local-variable 'font-lock-defaults)
  (setq major-mode 'n3-mode
	mode-name               "N3"	
	font-lock-defaults      '(n3-font-lock-keywords))
  ;; Comment stuff.
  (make-local-variable 'comment-start)
  (setq comment-start "#")
  (make-local-variable 'comment-end)
  (setq comment-end "")
  (make-local-variable 'comment-start-skip)
  (setq comment-start-skip "#+[ \t]*")

  (run-hooks 'n3-mode-hook)
)


(provide 'n3-mode)