Re: [BUG] No fontification when font-lock-add-keywords is passed nil as the mode

[Richard Stallman]

Does this fix it?  Could people who are more familiar
with font-lock mode verify this is correct?  I have changed
the format of a "compiled" keywords list, which might have introduced
some bugs.

*** font-lock.el        29 May 2004 15:23:35 -0400      1.220
--- font-lock.el        20 Jun 2004 21:02:44 -0400      
***************
*** 340,346 ****
  
  (defvar font-lock-keywords nil
    "A list of the keywords to highlight.
! Each element should have one of these forms:
  
   MATCHER
   (MATCHER . MATCH)
--- 340,354 ----
  
  (defvar font-lock-keywords nil
    "A list of the keywords to highlight.
! There are two kinds of values: user-level, and compiled.
! 
! A user-level keywords list is what a major mode or the user would
! set up.  Normally the list would come from `font-lock-defaults'.
! through selection of a fontification level and evaluation of any
! contained expressions.  You can also alter it by calling
! `font-lock-add-keywords' or `font-lock-remove-keywords' with MODE = nil.
! 
! Each element in a user-level keywords list should have one of these forms:
  
   MATCHER
   (MATCHER . MATCH)
***************
*** 438,444 ****
  
  This variable is set by major modes via the variable `font-lock-defaults'.
  Be careful when composing regexps for this list; a poorly written pattern can
! dramatically slow things down!")
  
  (defvar font-lock-keywords-alist nil
    "*Alist of `font-lock-keywords' local to a `major-mode'.
--- 446,459 ----
  
  This variable is set by major modes via the variable `font-lock-defaults'.
  Be careful when composing regexps for this list; a poorly written pattern can
! dramatically slow things down!
! 
! A compiled keywords list starts with t.  It is produced internal
! by `font-lock-compile-keywords' from a user-level keywords list.
! Its second element is the user-level keywords list that was
! compiled.  The remaining elements have the same form as
! user-level keywords, but normally their values have been
! optimized.")
  
  (defvar font-lock-keywords-alist nil
    "*Alist of `font-lock-keywords' local to a `major-mode'.
***************
*** 659,674 ****
         (font-lock-update-removed-keyword-alist mode keywords append))
        (t
         ;; Otherwise set or add the keywords now.
         (font-lock-set-defaults)
!        (if (eq append 'set)
!            (setq font-lock-keywords keywords)
!          (font-lock-remove-keywords nil keywords) ;to avoid duplicates
!          (let ((old (if (eq (car-safe font-lock-keywords) t)
!                         (cdr font-lock-keywords)
!                       font-lock-keywords)))
!            (setq font-lock-keywords (if append
!                                         (append old keywords)
!                                       (append keywords old))))))))
  
  (defun font-lock-update-removed-keyword-alist (mode keywords append)
    ;; Update `font-lock-removed-keywords-alist' when adding new
--- 674,699 ----
         (font-lock-update-removed-keyword-alist mode keywords append))
        (t
         ;; Otherwise set or add the keywords now.
+        ;; This is a no-op if it has been done already in this buffer.
         (font-lock-set-defaults)
!        (let ((was-compiled (eq (car font-lock-keywords) t)))
!          ;; Bring back the user-level (uncompiled) keywords.
!          (if was-compiled
!              (setq font-lock-keywords (cadr font-lock-keywords)))
!          ;; Now modify or replace them.
!          (if (eq append 'set)
!              (setq font-lock-keywords keywords)
!            (font-lock-remove-keywords nil keywords) ;to avoid duplicates
!            (let ((old (if (eq (car-safe font-lock-keywords) t)
!                           (cdr font-lock-keywords)
!                         font-lock-keywords)))
!              (setq font-lock-keywords (if append
!                                           (append old keywords)
!                                         (append keywords old)))))
!          ;; If the keywords were compiled before, compile them again.
!          (if was-compiled
!              (set (make-local-variable 'font-lock-keywords)
!                   (font-lock-compile-keywords keywords t)))))))
  
  (defun font-lock-update-removed-keyword-alist (mode keywords append)
    ;; Update `font-lock-removed-keywords-alist' when adding new
***************
*** 762,774 ****
        (t
         ;; Otherwise remove it immediately.
         (font-lock-set-defaults)
!        (setq font-lock-keywords (copy-sequence font-lock-keywords))
!        (dolist (keyword keywords)
!          (setq font-lock-keywords
!                (delete keyword
!                        ;; The keywords might be compiled.
!                        (delete (font-lock-compile-keyword keyword)
!                                font-lock-keywords)))))))
  
  ;;; Font Lock Support mode.
  
--- 787,807 ----
        (t
         ;; Otherwise remove it immediately.
         (font-lock-set-defaults)
!        (let ((was-compiled (eq (car font-lock-keywords) t)))
!          ;; Bring back the user-level (uncompiled) keywords.
!          (if was-compiled
!              (setq font-lock-keywords (cadr font-lock-keywords)))
! 
!          ;; Edit them.
!          (setq font-lock-keywords (copy-sequence font-lock-keywords))
!          (dolist (keyword keywords)
!            (setq font-lock-keywords
!                  (delete keyword font-lock-keywords)))
! 
!          ;; If the keywords were compiled before, compile them again.
!          (if was-compiled
!              (set (make-local-variable 'font-lock-keywords)
!                   (font-lock-compile-keywords keywords t)))))))
  
  ;;; Font Lock Support mode.
  
***************
*** 1349,1355 ****
      (setq font-lock-keywords
          (font-lock-compile-keywords font-lock-keywords t)))
    (let ((case-fold-search font-lock-keywords-case-fold-search)
!       (keywords (cdr font-lock-keywords))
        (bufname (buffer-name)) (count 0)
        keyword matcher highlights)
      ;;
--- 1382,1388 ----
      (setq font-lock-keywords
          (font-lock-compile-keywords font-lock-keywords t)))
    (let ((case-fold-search font-lock-keywords-case-fold-search)
!       (keywords (cddr font-lock-keywords))
        (bufname (buffer-name)) (count 0)
        keyword matcher highlights)
      ;;
***************
*** 1394,1407 ****
  ;; Various functions.
  
  (defun font-lock-compile-keywords (keywords &optional regexp)
!   "Compile KEYWORDS into the form (t KEYWORD ...).
! Here KEYWORD is of the form (MATCHER HIGHLIGHT ...) as shown in the
  `font-lock-keywords' doc string.
  If REGEXP is non-nil, it means these keywords are used for
  `font-lock-keywords' rather than for `font-lock-syntactic-keywords'."
    (if (eq (car-safe keywords) t)
        keywords
!     (setq keywords (cons t (mapcar 'font-lock-compile-keyword keywords)))
      (if (and regexp
             (eq (or syntax-begin-function
                     font-lock-beginning-of-syntax-function)
--- 1427,1442 ----
  ;; Various functions.
  
  (defun font-lock-compile-keywords (keywords &optional regexp)
!   "Compile KEYWORDS into the form (t KEYWORDS COMPILED...)
! Here each COMPILED is of the form (MATCHER HIGHLIGHT ...) as shown in the
  `font-lock-keywords' doc string.
  If REGEXP is non-nil, it means these keywords are used for
  `font-lock-keywords' rather than for `font-lock-syntactic-keywords'."
    (if (eq (car-safe keywords) t)
        keywords
!     (setq keywords
!         (cons t (cons keywords
!                       (mapcar 'font-lock-compile-keyword keywords))))
      (if (and regexp
             (eq (or syntax-begin-function
                     font-lock-beginning-of-syntax-function)
***************
*** 1512,1528 ****
        ;; Variable alist?
        (dolist (x (nthcdr 5 defaults))
        (set (make-local-variable (car x)) (cdr x)))
!       ;; Setup `font-lock-keywords' last because its value might depend
        ;; on other settings (e.g. font-lock-compile-keywords uses
        ;; font-lock-beginning-of-syntax-function).
        (set (make-local-variable 'font-lock-keywords)
!          (font-lock-compile-keywords (font-lock-eval-keywords keywords) t))
        ;; Local fontification?
        (while local
        (font-lock-add-keywords nil (car (car local)) (cdr (car local)))
        (setq local (cdr local)))
        (when removed-keywords
!       (font-lock-remove-keywords nil removed-keywords)))))
  
  ;;; Colour etc. support.
  
--- 1547,1567 ----
        ;; Variable alist?
        (dolist (x (nthcdr 5 defaults))
        (set (make-local-variable (car x)) (cdr x)))
!       ;; Set up `font-lock-keywords' last because its value might depend
        ;; on other settings (e.g. font-lock-compile-keywords uses
        ;; font-lock-beginning-of-syntax-function).
        (set (make-local-variable 'font-lock-keywords)
!          (font-lock-eval-keywords keywords))
        ;; Local fontification?
        (while local
        (font-lock-add-keywords nil (car (car local)) (cdr (car local)))
        (setq local (cdr local)))
        (when removed-keywords
!       (font-lock-remove-keywords nil removed-keywords))
!       ;; Now compile the keywords.
!       (unless (eq (car font-lock-keywords) t)
!       (set (make-local-variable 'font-lock-keywords)
!            (font-lock-compile-keywords keywords t))))))
  
  ;;; Colour etc. support.