Highlighting correctly in an emacs major mode

Question

I am developing an emacs major mode for a language (aka mydsl). However, using the techniques on xahlee\'s site doesn\'t seem to be working for some reason (possibly ol

Answer 1

You have a couple of syntactic problems in your code, but you got it nearly correct. Here's my edited version which appears to do the right thing for a buffer in mydsl-mode:

; No changes to the simple vars
(defvar mydsl-events
  '("reservedword1"  
    "reservedword2"))

(defvar mydsl-keywords
  '("other-keyword" "another-keyword"))

;; I'd probably put in a default that you want, as opposed to nil
(defvar mydsl-tab-width nil "Width of a tab for MYDSL mode")

;; Two small edits.
;; First is to put an extra set of parens () around the list
;; which is the format that font-lock-defaults wants
;; Second, you used ' (quote) at the outermost level where you wanted ` (backquote)
;; you were very close
(defvar mydsl-font-lock-defaults
  `((
     ;; stuff between "
     ("\"\\.\\*\\?" . font-lock-string-face)
     ;; ; : , ; { } =>  @ $ = are all special elements
     (":\\|,\\|;\\|{\\|}\\|=>\\|@\\|$\\|=" . font-lock-keyword-face)
     ( ,(regexp-opt mydsl-keywords 'words) . font-lock-builtin-face)
     ( ,(regexp-opt mydsl-events 'words) . font-lock-constant-face)
     )))

(define-derived-mode mydsl-mode fundamental-mode "MYDSL script"
  "MYDSL mode is a major mode for editing MYDSL  files"

  ;; fundamental-mode kills all local variables, no need to do it again
  (setq mode-name "MYDSL script")

  ;; you again used quote when you had '((mydsl-hilite))
  ;; I just updated the variable to have the proper nesting (as noted above)
  ;; and use the value directly here
  (setq font-lock-defaults mydsl-font-lock-defaults)

  ;; when there's an override, use it
  ;; otherwise it gets the default value
  (when mydsl-tab-width
    (setq tab-width mydsl-tab-width))

  ;; for comments
  ;; overriding these vars gets you what (I think) you want
  ;; they're made buffer local when you set them
  (setq comment-start "#")
  (setq comment-end "")

  (modify-syntax-entry ?# "< b" mydsl-mode-syntax-table)
  (modify-syntax-entry ?\n "> b" mydsl-mode-syntax-table)
  ;;A gnu-correct program will have some sort of hook call here.
  )

(provide 'mydsl-mode)