Syntax highlighting using Emacs

Question

I'm creating an elisp file based on http://ergoemacs.org/emacs/elisp_syntax_coloring.html from this site.

My updated code is shown below

;;; MOD5-mode.el --- sample major mode for editing MOD5 code.

;; Copyleft © 2016, by 

;; Author:  (@gmail.com)
;; Version: 0.0.1
;; Created: 07-Sep-2016
;; Keywords: languages
;; Homepage: n/a

;; This file is not part of GNU Emacs.

;;; License:

;; You can redistribute this program and/or modify it under the terms of the GNU General Public License version 2.

;;; Commentary:

;; This elisp file will enable the highlight of the MOD5 code when viewed in Emacs.

;; ********* probably a link will be helpful here - under construction ***********

;;; Code:

;; define several category of keywords
(setq MOD5-keywords '("SEQ_SKEL" "NEMG" "NSDN" "SSTEP" "STEP" "START" "SCU" "LAMP" "HORN" "PRINTER" "MODULE" "END MODULE" "CALL TEMPLATE" "IF" "FOR") )
(setq MOD5-types '("AI" "AO" "DI" "DO" "AISIM" "DISIM" "ACO" "AIM" "AOT" "DOT" "AP" "AC" "DC" "DT" "DM" "AK" "AG" "AR" "TA"))
(setq MOD5-constants '("PFS" "NFS" "IONE" "ZERO"))
(setq MOD5-events '("WARN" "REQ" "ALT"))
(setq MOD5-functions '("ALM_DI_DO05B" "IFD03B" "ALM_4S_AX04B" "ALM_DX05B" "ALM_RERING03B" "ALM_DI_DO05B" "IS04B"))
(setq MOD5-operators '("=" "AND" "OR" "XOR"))
(setq MOD5-acmdb '("\[(&A-Z0-9_)\]+" "\[(:A-Z0-9_)\]"))

;; generate regex string for each category of keywords
(setq MOD5-keywords-regexp (regexp-opt MOD5-keywords 'words))
(setq MOD5-type-regexp (regexp-opt MOD5-types 'words))
(setq MOD5-constant-regexp (regexp-opt MOD5-constants 'words))
(setq MOD5-event-regexp (regexp-opt MOD5-events 'words))
(setq MOD5-functions-regexp (regexp-opt MOD5-functions 'words))
(setq MOD5-operators-regexp (regexp-opt MOD5-operators 'words))
(setq MOD5-acmdb-regexp (regexp-opt MOD5-acmdb 'words))

;; create the list for font-lock.
;; each category of keyword is given a particular face
(setq MOD5-font-lock-keywords
      `(
        (,MOD5-type-regexp . font-lock-type-face)
        (,MOD5-constant-regexp . font-lock-constant-face)
        (,MOD5-event-regexp . font-lock-builtin-face)
        (,MOD5-functions-regexp . font-lock-function-name-face)
        (,MOD5-keywords-regexp . font-lock-keyword-face)
    (,MOD5-acmdb-regexp . font-lock-variable-name-face)
    (,MOD5-operators-regexp . font-lock-negation-char-face)
        ;; note: order above matters, because once colored, that part won't change.
        ;; in general, longer words first
        ))

;;;###autoload
(define-derived-mode MOD5-mode fundamental-mode
  "MOD5 mode"
  "Major mode for editing MOD5 Dowtran Code…"

  ;; code for syntax highlighting
  (setq font-lock-defaults '((MOD5-font-lock-keywords))))

;; clear memory. no longer needed
(setq MOD5-keywords nil)
(setq MOD5-types nil)
(setq MOD5-constants nil)
(setq MOD5-events nil)
(setq MOD5-functions nil)
(setq MOD5-acmdb nil)
(setq MOD5-operators nil)

;; clear memory. no longer needed
(setq MOD5-keywords-regexp nil)
(setq MOD5-types-regexp nil)
(setq MOD5-constants-regexp nil)
(setq MOD5-events-regexp nil)
(setq MOD5-functions-regexp nil)
(setq MOD5-acmdb-regexp nil)
(setq MOD5-operators-regexp nil)

;; add the mode to the `features' list
(provide 'MOD5-mode)

;; Local Variables:
;; coding: utf-8
;; End:

;;; MOD5-mode.el ends here

In the above code, I'm unable to get the following to work:

(setq MOD5-operators '("=" "AND" "OR" "XOR"))
(setq MOD5-acmdb '("\[(&A-Z0-9_)\]+" "\[(:A-Z0-9_)\]"))

What is wrong here? I have copy-pasted the existing code and created the above two lines and for some reason they do not highlight what is within quotes.

And also the regex "\[(&A-Z0-9_)\]+" "\[(:A-Z0-9_)\]" is intended to match text like

1. :ALM_SIP_PROB_123
2. (:ALM_SIP_PROB_123)
3. (&:ALM_SIP_PROB_123)
4. PIT14501

I'm using the following to generate the regex string:

(setq MOD5-operators-regexp (regexp-opt MOD5-operators 'words))
(setq MOD5-acmdb-regexp (regexp-opt MOD5-acmdb 'words))

I'm wondering if something could be wrong with this?

Update - Adding a sample program

From the above image you can see that the OR, AND have not been highlighted.
Also the numbers within parenthesis have not been highlighted

Update - Changed the elisp code - face name updated from font-lock-operator to font-lock-negation-char-face

(,MOD5-operators-regexp . font-lock-negation-char-face)

Answer 1

When I try your code, it highlights more than it does in your example, including the AND:s. Try to restart Emacs and see if anything you've done earlier caused this.

However, there are some remaining problems: You can't apply regexp-opt to regexp:s, it only work on plain strings, so the setup of MOD5-acmdb doesn't work. Unfortunately, it's not 100% clear what you are trying to match, but try write a plain regexp without using regexp-opt.

You can't highlight = if you pass words to regexp-opt, so I suggest that you match it separately from AND, OR and XOR. (The reason is that the resulting regexp contains \< and \> to match the start and end of a word, but = isn't a word character.)

Minor details:

• Your regexp will match words inside symbols, as the AND in THIS_AND_THAT. This is easily fixed by passing symbols instead of words to regexp-opt.
• You can use let to create temporary variables rather that setting them using setq and later setting them to nil.
• In elisp strings, you will need two backslashes to yeild one. In other words, you need "\\[" to create the regexp snippet \[. ("\[" is the same as "[".)
• If you would like to interactively debug your font-lock rules, you can use https://github.com/Lindydancer/font-lock-studio