emacs/lisp/font-lock.el

;; Electric Font Lock Mode
;; Copyright (C) 1992, 1993, 1994, 1995 Free Software Foundation, Inc.

;; Author: jwz, then rms and sm <simon@gnu.ai.mit.edu>
;; Maintainer: FSF
;; Keywords: languages, faces

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

;;; Commentary:

;; Font Lock mode is a minor mode that causes your comments to be displayed in
;; one face, strings in another, reserved words in another, and so on.
;;
;; Comments will be displayed in `font-lock-comment-face'.
;; Strings will be displayed in `font-lock-string-face'.
;; Regexps are used to display selected patterns in other faces.
;;
;; To make the text you type be fontified, use M-x font-lock-mode.
;; When this minor mode is on, the faces of the current line are
;; updated with every insertion or deletion.
;;
;; To turn Font Lock mode on automatically, add this to your .emacs file:
;;
;;  (add-hook 'emacs-lisp-mode-hook 'turn-on-font-lock)
;;
;; On a Sparc2, `font-lock-fontify-buffer' takes about 10 seconds for a 120k
;; file of C code using the default configuration, and about 25 seconds using
;; the more extensive configuration, though times also depend on file contents.
;; You can speed this up substantially by removing some of the patterns that
;; are highlighted by default.  Fontifying Lisp code is significantly faster,
;; because Lisp has a more regular syntax than C, so the expressions don't have
;; to be as hairy.
;;
;; If you add patterns for a new mode, say foo.el's `foo-mode', say in which
;; you don't want syntactic fontification to occur, you can make Font Lock mode
;; use your regexps when turning on Font Lock by adding to `foo-mode-hook':
;;
;;  (add-hook 'foo-mode-hook
;;   '(lambda () (make-local-variable 'font-lock-defaults)
;;               (setq font-lock-defaults '(foo-font-lock-keywords t))))
;;
;; Nasty regexps of the form "bar\\(\\|lo\\)\\|f\\(oo\\|u\\(\\|bar\\)\\)\\|lo"
;; are made thusly: (make-regexp '("foo" "fu" "fubar" "bar" "barlo" "lo")) for
;; efficiency.  See /pub/gnu/emacs/elisp-archive/functions/make-regexp.el.Z on
;; archive.cis.ohio-state.edu for this and other functions.

;;; Code:

(defvar font-lock-comment-face 'font-lock-comment-face
  "Face to use for comments.")

(defvar font-lock-string-face 'font-lock-string-face
  "Face to use for strings.")

(defvar font-lock-function-name-face 'font-lock-function-name-face
  "Face to use for function names.")

(defvar font-lock-variable-name-face 'font-lock-variable-name-face
  "Face to use for variable names.")

(defvar font-lock-keyword-face 'font-lock-keyword-face
  "Face to use for keywords.")

(defvar font-lock-type-face 'font-lock-type-face
  "Face to use for data types.")

(defvar font-lock-reference-face 'font-lock-reference-face
  "Face to use for references.")

(defvar font-lock-no-comments nil
  "Non-nil means Font Lock should not fontify comments or strings.")

(make-variable-buffer-local 'font-lock-keywords)
(defvar font-lock-keywords nil
  "*The keywords to highlight.
Elements should be of the form:

 MATCHER
 (MATCHER . MATCH)
 (MATCHER . FACENAME)
 (MATCHER . HIGHLIGHT)
 (MATCHER HIGHLIGHT ...)

where HIGHLIGHT should be of the form (MATCH FACENAME OVERRIDE LAXMATCH).
MATCHER can be either the regexp to search for, or the function name to call to
make the search (called with one argument, the limit of the search).  MATCH is
the subexpression of MATCHER to be highlighted.  FACENAME is an expression
whose value is the face name to use.  FACENAME's default attributes may be
defined in `font-lock-face-attributes'.

OVERRIDE and LAXMATCH are flags.  If OVERRIDE is t, existing fontification may
be overriden.  If `keep', only parts not already fontified are highlighted.
If LAXMATCH is non-nil, no error is signalled if there is no MATCH in MATCHER.

These regular expressions should not match text which spans lines.  While
\\[font-lock-fontify-buffer] handles multi-line patterns correctly, updating
when you edit the buffer does not, since it considers text one line at a time.

Be careful composing regexps for this list;
the wrong pattern can dramatically slow things down!")

(defvar font-lock-defaults nil
  "If set by a major mode, should be the defaults for Font Lock mode.
The value should look like the `cdr' of an item in `font-lock-defaults-alist'.")

(defvar font-lock-defaults-alist
  (let ((tex-mode-defaults '(tex-font-lock-keywords nil nil ((?$ . "\""))))
	(c-mode-defaults
	 '((c-font-lock-keywords c-font-lock-keywords-1 c-font-lock-keywords-2)
	   nil nil ((?_ . "w"))))
	(c++-mode-defaults
	 '((c++-font-lock-keywords c++-font-lock-keywords-1 
				   c++-font-lock-keywords-2)
	   nil nil ((?_ . "w"))))
	(lisp-mode-defaults
	 '((lisp-font-lock-keywords lisp-font-lock-keywords-1
				    lisp-font-lock-keywords-2)
	   nil nil ((?: . "w") (?- . "w") (?* . "w")))))
    (list
     (cons 'bibtex-mode		tex-mode-defaults)
     (cons 'c++-c-mode		c-mode-defaults)
     (cons 'c++-mode		c++-mode-defaults)
     (cons 'c-mode		c-mode-defaults)
     (cons 'emacs-lisp-mode	lisp-mode-defaults)
     (cons 'latex-mode		tex-mode-defaults)
     (cons 'lisp-mode		lisp-mode-defaults)
     (cons 'plain-tex-mode	tex-mode-defaults)
     (cons 'scheme-mode		lisp-mode-defaults)
     (cons 'slitex-mode		tex-mode-defaults)
     (cons 'tex-mode		tex-mode-defaults)))
  "*Alist of default major mode and Font Lock defaults.
Each item should be a list of the form:
 (MAJOR-MODE . (FONT-LOCK-KEYWORDS KEYWORDS-ONLY CASE-FOLD FONT-LOCK-SYNTAX))
where MAJOR-MODE is a symbol, and FONT-LOCK-KEYWORDS may be a symbol or a list
of symbols.  If KEYWORDS-ONLY is non-nil, syntactic fontification (strings and
comments) is not performed.  If CASE-FOLD is non-nil, the case of the keywords
is ignored when fontifying.  FONT-LOCK-SYNTAX should be a list of cons pairs of
the form (CHAR . STRING), it is used to set the local Font Lock syntax table
for keyword fontification.")

(defvar font-lock-keywords-case-fold-search nil
  "*Non-nil means the patterns in `font-lock-keywords' are case-insensitive.")

(defvar font-lock-syntax-table nil
  "Non-nil means use this syntax table for fontifying.
If this is nil, the major mode's syntax table is used.")

(defvar font-lock-verbose t
  "*Non-nil means `font-lock-fontify-buffer' should print status messages.")

;;;###autoload
(defvar font-lock-maximum-decoration nil
  "Non-nil means use the maximum decoration for fontifying.
If nil, use the default decoration (typically the minimum available).
If t, use the maximum decoration available.
If a number, use that level of decoration (or if not available the maximum).")

(defvar font-lock-maximum-size
  (if font-lock-maximum-decoration (* 150 1024) (* 300 1024))
  "*If non-nil, the maximum size for buffers.
Only buffers less than this can be fontified when Font Lock mode is turned on.
If nil, means size is irrelevant.")

;;;###autoload
(defvar font-lock-mode-hook nil
  "Function or functions to run on entry to Font Lock mode.")

;; Colour etc. support.

(defvar font-lock-display-type nil
  "A symbol indicating the display Emacs is running under.
The symbol should be one of `color', `grayscale' or `mono'.
If Emacs guesses this display attribute wrongly, either set this variable in
your `~/.emacs' or set the resource `Emacs.displayType' in your `~/.Xdefaults'.
See also `font-lock-background-mode' and `font-lock-face-attributes'.")

(defvar font-lock-background-mode nil
  "A symbol indicating the Emacs background brightness.
The symbol should be one of `light' or `dark'.
If Emacs guesses this frame attribute wrongly, either set this variable in
your `~/.emacs' or set the resource `Emacs.backgroundMode' in your
`~/.Xdefaults'.
See also `font-lock-display-type' and `font-lock-face-attributes'.")

(defvar font-lock-face-attributes nil
  "A list of default attributes to use for face attributes.
Each element of the list should be of the form

 (FACE FOREGROUND BACKGROUND BOLD-P ITALIC-P UNDERLINE-P)

where FACE should be one of the face symbols `font-lock-comment-face',
`font-lock-string-face', `font-lock-keyword-face', `font-lock-type-face',
`font-lock-function-name-face', `font-lock-variable-name-face', and
`font-lock-reference-face'.  A form for each of these face symbols should be
provided in the list, but other face symbols and attributes may be given and
used in highlighting.  See `font-lock-keywords'.

Subsequent element items should be the attributes for the corresponding
Font Lock mode faces.  Attributes FOREGROUND and BACKGROUND should be strings
\(default if nil), while BOLD-P, ITALIC-P, and UNDERLINE-P should specify the
corresponding face attributes (yes if non-nil).

Emacs uses default attributes based on display type and background brightness.
See variables `font-lock-display-type' and `font-lock-background-mode'.

Resources can be used to over-ride these face attributes.  For example, the
resource `Emacs.font-lock-comment-face.attributeUnderline' can be used to
specify the UNDERLINE-P attribute for face `font-lock-comment-face'.")

(defun font-lock-make-faces (&optional override)
  "Make faces from `font-lock-face-attributes'.
A default list is used if this is nil.
If optional OVERRIDE is non-nil, faces that already exist are reset.
See `font-lock-make-face' and `list-faces-display'."
  ;; We don't need to `setq' any of these variables, but the user can see what
  ;; is being used if we do.
  (if (null font-lock-display-type)
      (setq font-lock-display-type
	    (let ((display-resource (x-get-resource ".displayType"
						    "DisplayType")))
	      (cond (display-resource (intern (downcase display-resource)))
		    ((x-display-color-p) 'color)
		    ((x-display-grayscale-p) 'grayscale)
		    (t 'mono)))))
  (if (null font-lock-background-mode)
      (setq font-lock-background-mode
	    (let ((bg-resource (x-get-resource ".backgroundMode"
					       "BackgroundMode"))
		  (params (frame-parameters)))
	      (cond (bg-resource (intern (downcase bg-resource)))
		    ((< (apply '+ (x-color-values
				   (cdr (assq 'background-color params))))
			(/ (apply '+ (x-color-values "white")) 3))
		     'dark)
		    (t 'light)))))
  (if (null font-lock-face-attributes)
      (setq font-lock-face-attributes
	    (let ((light-bg (eq font-lock-background-mode 'light)))
	      (cond ((memq font-lock-display-type '(mono monochrome))
		     ;; Emacs 19.25's font-lock defaults:
		     ;;'((font-lock-comment-face nil nil nil t nil)
		     ;;  (font-lock-string-face nil nil nil nil t)
		     ;;  (font-lock-keyword-face nil nil t nil nil)
		     ;;  (font-lock-function-name-face nil nil t t nil)
		     ;;  (font-lock-type-face nil nil nil t nil))
		     (list '(font-lock-comment-face nil nil t t nil)
			   '(font-lock-string-face nil nil nil t nil)
			   '(font-lock-keyword-face nil nil t nil nil)
			   (list
			    'font-lock-function-name-face
			    (cdr (assq 'background-color (frame-parameters)))
			    (cdr (assq 'foreground-color (frame-parameters)))
			    t nil nil)
			   '(font-lock-variable-name-face nil nil t t nil)
			   '(font-lock-type-face nil nil t nil t)
			   '(font-lock-reference-face nil nil t nil t)))
		    ((memq font-lock-display-type '(grayscale greyscale
						    grayshade greyshade))
		     (list
		      (list 'font-lock-comment-face
			    nil (if light-bg "Gray80" "DimGray") t t nil)
		      (list 'font-lock-string-face
			    nil (if light-bg "Gray50" "LightGray") nil t nil)
		      (list 'font-lock-keyword-face
			    nil (if light-bg "Gray90" "DimGray") t nil nil)
		      (list 'font-lock-function-name-face
			    (cdr (assq 'background-color (frame-parameters)))
			    (cdr (assq 'foreground-color (frame-parameters)))
			    t nil nil)
		      (list 'font-lock-variable-name-face
			    nil (if light-bg "Gray90" "DimGray") t t nil)
		      (list 'font-lock-type-face
			    nil (if light-bg "Gray80" "DimGray") t nil t)
		      (list 'font-lock-reference-face
			    nil (if light-bg "LightGray" "Gray50") t nil t)))
		    (light-bg		; light colour background
		     '((font-lock-comment-face "Firebrick")
		       (font-lock-string-face "RosyBrown")
		       (font-lock-keyword-face "Purple")
		       (font-lock-function-name-face "Blue")
		       (font-lock-variable-name-face "DarkGoldenrod")
		       (font-lock-type-face "DarkOliveGreen")
		       (font-lock-reference-face "CadetBlue")))
		    (t			; dark colour background
		     '((font-lock-comment-face "OrangeRed")
		       (font-lock-string-face "LightSalmon")
		       (font-lock-keyword-face "LightSteelBlue")
		       (font-lock-function-name-face "LightSkyBlue")
		       (font-lock-variable-name-face "LightGoldenrod")
		       (font-lock-type-face "PaleGreen")
		       (font-lock-reference-face "Aquamarine")))))))
  ;; Now make the faces if we have to.
  (mapcar (function (lambda (face-attributes)
	     (let ((face (nth 0 face-attributes)))
               (if override
                   (font-lock-make-face face-attributes)
                 (if (not (and (boundp face) (facep (symbol-value face))))
                     (if (facep face)
                         (set face face)
                       (font-lock-make-face face-attributes)))))))
	  font-lock-face-attributes))

(defun font-lock-make-face (face-attributes)
  "Make a face from FACE-ATTRIBUTES.
FACE-ATTRIBUTES should be like an element `font-lock-face-attributes', so that
the face name is the first item in the list.  A variable with the same name as
the face is also set; its value is the face name."
  (let* ((face (nth 0 face-attributes))
	 (face-name (symbol-name face))
	 (set-p (function (lambda (face-name resource)
		 (x-get-resource (concat face-name ".attribute" resource)
				 (concat "Face.Attribute" resource)))))
	 (on-p (function (lambda (face-name resource)
		(let ((set (funcall set-p face-name resource)))
		  (and set (member (downcase set) '("on" "true"))))))))
    (make-face face)
    ;; Set attributes not set from X resources (and therefore `make-face').
    (or (funcall set-p face-name "Foreground")
	(condition-case nil
	    (set-face-foreground face (nth 1 face-attributes))
	  (error nil)))
    (or (funcall set-p face-name "Background")
	(condition-case nil
	    (set-face-background face (nth 2 face-attributes))
	  (error nil)))
    (if (funcall set-p face-name "Bold")
	(and (funcall on-p face-name "Bold") (make-face-bold face nil t))
      (and (nth 3 face-attributes) (make-face-bold face nil t)))
    (if (funcall set-p face-name "Italic")
	(and (funcall on-p face-name "Italic") (make-face-italic face nil t))
      (and (nth 4 face-attributes) (make-face-italic face nil t)))
    (or (funcall set-p face-name "Underline")
	(set-face-underline-p face (nth 5 face-attributes)))
    (set face face)))

;; Fontification.

;; These variables record, for each buffer, the parse state at a particular
;; position, always the start of a line.  Used to make font-lock-fontify-region
;; faster.
(defvar font-lock-cache-position nil)
(defvar font-lock-cache-state nil)
(make-variable-buffer-local 'font-lock-cache-position)
(make-variable-buffer-local 'font-lock-cache-state)

(defun font-lock-fontify-region (start end &optional loudly)
  "Put proper face on each string and comment between START and END."
  (save-excursion
    (save-restriction
      (widen)
      (goto-char start)
      (beginning-of-line)
      (if loudly (message "Fontifying %s... (syntactically...)" (buffer-name)))
      (let ((inhibit-read-only t) (buffer-undo-list t) (buffer-file-name)
	    (modified (buffer-modified-p))
	    (old-syntax (syntax-table))
	    (synstart (if comment-start-skip
			  (concat "\\s\"\\|" comment-start-skip)
			"\\s\""))
	    (comstart (if comment-start-skip
			  (concat "\\s<\\|" comment-start-skip)
			"\\s<"))
	    (startline (point))
	    state prev prevstate)
	(unwind-protect
	    (progn
	      (if font-lock-syntax-table
		  (set-syntax-table font-lock-syntax-table))
	      ;; Find the state at the line-beginning before START.
	      (if (eq startline font-lock-cache-position)
		  (setq state font-lock-cache-state)
		;; Find outermost containing sexp.
		(beginning-of-defun)
		;; Find the state at STARTLINE.
		(while (< (point) startline)
		  (setq state (parse-partial-sexp (point) startline 0)))
		(setq font-lock-cache-state state
		      font-lock-cache-position (point)))
	      ;; Now find the state precisely at START.
	      (setq state (parse-partial-sexp (point) start nil nil state))
	      ;; If the region starts inside a string, show the extent of it.
	      (if (nth 3 state)
		  (let ((beg (point)))
		    (while (and (re-search-forward "\\s\"" end 'move)
				(nth 3 (parse-partial-sexp beg (point) nil nil
							   state))))
		    (put-text-property beg (point) 'face font-lock-string-face)
		    (setq state (parse-partial-sexp beg (point)
						    nil nil state))))
	      ;; Likewise for a comment.
	      (if (or (nth 4 state) (nth 7 state))
		  (let ((beg (point)))
		    (save-restriction
		      (narrow-to-region (point-min) end)
		      (condition-case nil
			  (progn
			    (re-search-backward comstart (point-min) 'move)
			    (forward-comment 1)
			    ;; forward-comment skips all whitespace,
			    ;; so go back to the real end of the comment.
			    (skip-chars-backward " \t"))
			(error (goto-char end))))
		    (put-text-property beg (point) 'face
				       font-lock-comment-face)
		    (setq state (parse-partial-sexp beg (point)
						    nil nil state))))
	      ;; Find each interesting place between here and END.
	      (while (and (< (point) end)
			  (setq prev (point) prevstate state)
			  (re-search-forward synstart end t)
			  (progn
			    ;; Clear out the fonts of what we skip over.
			    (remove-text-properties prev (point) '(face nil))
			    ;; Verify the state at that place
			    ;; so we don't get fooled by \" or \;.
			    (setq state (parse-partial-sexp prev (point)
							    nil nil state))))
		(let ((here (point)))
		  (if (or (nth 4 state) (nth 7 state))
		      ;; We found a real comment start.
		      (let ((beg (match-beginning 0)))
			(goto-char beg)
			(save-restriction
			  (narrow-to-region (point-min) end)
			  (condition-case nil
			      (progn
				(forward-comment 1)
				;; forward-comment skips all whitespace,
				;; so go back to the real end of the comment.
				(skip-chars-backward " \t"))
			    (error (goto-char end))))
			(put-text-property beg (point) 'face
					   font-lock-comment-face)
			(setq state (parse-partial-sexp here (point)
							nil nil state)))
		    (if (nth 3 state)
			(let ((beg (match-beginning 0)))
			  (while (and (re-search-forward "\\s\"" end 'move)
				      (nth 3 (parse-partial-sexp
					      here (point) nil nil state))))
			  (put-text-property beg (point) 'face
					     font-lock-string-face)
			  (setq state (parse-partial-sexp here (point)
							  nil nil state))))))
		;; Make sure PREV is non-nil after the loop
		;; only if it was set on the very last iteration.
		(setq prev nil)))
	  (set-syntax-table old-syntax)
	  (and prev
	       (remove-text-properties prev end '(face nil)))
	  (and (buffer-modified-p)
	       (not modified)
	       (set-buffer-modified-p nil)))))))
	  

(defun font-lock-unfontify-region (beg end)
  (let ((modified (buffer-modified-p))
	(buffer-undo-list t) (inhibit-read-only t) (buffer-file-name))
    (remove-text-properties beg end '(face nil))
    (and (buffer-modified-p)
	 (not modified)
	 (set-buffer-modified-p nil))))

;; Called when any modification is made to buffer text.
(defun font-lock-after-change-function (beg end old-len)
  (save-excursion
    (save-match-data
      ;; Discard the cache info if text before it has changed.
      (and font-lock-cache-position
	   (> font-lock-cache-position beg)
	   (setq font-lock-cache-position nil))
      ;; Rescan between start of line from `beg' and start of line after `end'.
      (goto-char beg)
      (beginning-of-line)
      (setq beg (point))
      (goto-char end)
      (forward-line 1)
      (setq end (point))
      ;; First scan for strings and comments.
      ;; Must scan from line start in case of
      ;; inserting space into `intfoo () {}', and after widened.
      (if font-lock-no-comments
	  (font-lock-unfontify-region beg end)
	(font-lock-fontify-region beg end))
      ;; Now scan for keywords.
      (font-lock-hack-keywords beg end))))

;; The following must be rethought, since keywords can override fontification.
;      ;; Now scan for keywords, but not if we are inside a comment now.
;      (or (and (not font-lock-no-comments)
;	       (let ((state (parse-partial-sexp beg end nil nil 
;						font-lock-cache-state)))
;		 (or (nth 4 state) (nth 7 state))))
;	  (font-lock-hack-keywords beg end))

;;; Fontifying arbitrary patterns

(defun font-lock-compile-keywords (&optional keywords)
  ;; Compile `font-lock-keywords' into the form (t KEYWORD ...) where KEYWORD
  ;; is the (MATCHER HIGHLIGHT ...) shown in the variable's doc string.
  (let ((keywords (or keywords font-lock-keywords)))
    (setq font-lock-keywords 
     (if (eq (car-safe keywords) t)
	 keywords
       (cons t
	(mapcar
	 (function (lambda (item)
	    (cond ((nlistp item)
		   (list item '(0 font-lock-keyword-face)))
		  ((numberp (cdr item))
		   (list (car item) (list (cdr item) 'font-lock-keyword-face)))
		  ((symbolp (cdr item))
		   (list (car item) (list 0 (cdr item))))
		  ((nlistp (nth 1 item))
		   (list (car item) (cdr item)))
		  (t
		   item))))
	 keywords))))))

(defsubst font-lock-apply-highlight (highlight)
  "Apply HIGHLIGHT following a match.  See `font-lock-keywords'."
  (let* ((match (nth 0 highlight))
	 (beg (match-beginning match)) (end (match-end match))
	 (override (nth 2 highlight)))
    (cond ((not beg)
	   ;; No match but we might not signal an error
	   (or (nth 3 highlight) (error "Highlight %S failed" highlight)))
	  ((and (not override) (text-property-not-all beg end 'face nil))
	   ;; Can't override and already fontified
	   nil)
	  ((not (eq override 'keep))
	   ;; Can override but need not keep existing fontification
	   (put-text-property beg end 'face (eval (nth 1 highlight))))
	  (t
	   ;; Can override but must keep existing fontification
	   (let ((pos (text-property-any beg end 'face nil)) next
		 (face (eval (nth 1 highlight))))
	     (while pos
	       (setq next (next-single-property-change pos 'face nil end))
	       (put-text-property pos next 'face face)
	       (setq pos (text-property-any next end 'face nil))))))))

(defun font-lock-hack-keywords (start end &optional loudly)
  "Fontify according to `font-lock-keywords' between START and END."
  (let ((case-fold-search font-lock-keywords-case-fold-search)
	(keywords (cdr (if (eq (car-safe font-lock-keywords) t)
			   font-lock-keywords
			 (font-lock-compile-keywords))))
	(count 0)
	(inhibit-read-only t) (buffer-undo-list t) (buffer-file-name)
	(modified (buffer-modified-p))
	(old-syntax (syntax-table))
	(bufname (buffer-name)))
    (unwind-protect
	(let (keyword matcher highlights)
	  (if loudly (message "Fontifying %s... (regexps...)" bufname))
	  (if font-lock-syntax-table (set-syntax-table font-lock-syntax-table))
	  (while keywords
	    (setq keyword (car keywords) keywords (cdr keywords)
		  matcher (car keyword) highlights (cdr keyword))
	    (goto-char start)
	    (while (if (stringp matcher)
                       (re-search-forward matcher end t)
                     (funcall matcher end))
	      (mapcar 'font-lock-apply-highlight highlights))
	    (if loudly (message "Fontifying %s... (regexps...%s)" bufname
				(make-string (setq count (1+ count)) ?.)))))
      (set-syntax-table old-syntax)
      (and (buffer-modified-p)
	   (not modified)
	   (set-buffer-modified-p nil)))))

;; The user level functions

(defvar font-lock-mode nil) ; for modeline

(defvar font-lock-fontified nil) ; whether we have hacked this buffer
(put 'font-lock-fontified 'permanent-local t)

;;;###autoload
(defun font-lock-mode (&optional arg)
  "Toggle Font Lock mode.
With arg, turn Font Lock mode on if and only if arg is positive.

When Font Lock mode is enabled, text is fontified as you type it:

 - Comments are displayed in `font-lock-comment-face';
 - Strings are displayed in `font-lock-string-face';
 - Certain other expressions are displayed in other faces according to the
   value of the variable `font-lock-keywords'.

You can enable Font Lock mode in any major mode automatically by turning on in
the major mode's hook.  For example, put in your ~/.emacs:

 (add-hook 'c-mode-hook 'turn-on-font-lock)

Or for any visited file with the following in your ~/.emacs:

 (add-hook 'find-file-hooks 'turn-on-font-lock)

The default Font Lock mode faces and their attributes are defined in the
variable `font-lock-face-attributes', and Font Lock mode default settings in
the variable `font-lock-defaults-alist'.

Where modes support different levels of fontification, you can use the variable
`font-lock-maximum-decoration' to specify which level you generally prefer.
When you turn Font Lock mode on/off the buffer is fontified/defontified, though
fontification occurs only if the buffer is less than `font-lock-maximum-size'.
To fontify a buffer without turning on Font Lock mode, and regardless of buffer
size, you can use \\[font-lock-fontify-buffer]."
  (interactive "P")
  (let ((on-p (if arg (> (prefix-numeric-value arg) 0) (not font-lock-mode))))
    (if (equal (buffer-name) " *Compiler Input*") ; hack for bytecomp...
	(setq on-p nil))
    (if (not on-p)
	(remove-hook 'after-change-functions 'font-lock-after-change-function)
      (make-local-variable 'after-change-functions)
      (add-hook 'after-change-functions 'font-lock-after-change-function))
    (set (make-local-variable 'font-lock-mode) on-p)
    (cond (on-p
	   (font-lock-set-defaults)
	   (make-local-variable 'before-revert-hook)
	   (make-local-variable 'after-revert-hook)
	   ;; If buffer is reverted, must clean up the state.
	   (add-hook 'before-revert-hook 'font-lock-revert-setup)
	   (add-hook 'after-revert-hook 'font-lock-revert-cleanup)
	   (run-hooks 'font-lock-mode-hook)
	   (cond (font-lock-fontified
		  nil)
		 ((or (null font-lock-maximum-size)
		      (> font-lock-maximum-size (buffer-size)))
		  (font-lock-fontify-buffer))
		 (font-lock-verbose
		  (message "Fontifying %s... buffer too big." (buffer-name)))))
	  (font-lock-fontified
	   (setq font-lock-fontified nil)
	   (remove-hook 'before-revert-hook 'font-lock-revert-setup)
	   (remove-hook 'after-revert-hook 'font-lock-revert-cleanup)
	   (font-lock-unfontify-region (point-min) (point-max))
	   (font-lock-thing-lock-cleanup))
	  (t
	   (remove-hook 'before-revert-hook 'font-lock-revert-setup)
	   (remove-hook 'after-revert-hook 'font-lock-revert-cleanup)
	   (font-lock-thing-lock-cleanup)))
    (force-mode-line-update)))

;;;###autoload
(defun turn-on-font-lock ()
  "Unconditionally turn on Font Lock mode."
  (font-lock-mode 1))

;; Turn off other related packages if they're on.  I prefer a hook. --sm.
;; These explicit calls are easier to understand
;; because people know what they will do.
;; A hook is a mystery because it might do anything whatever. --rms.
(defun font-lock-thing-lock-cleanup ()
  (cond ((and (boundp 'fast-lock-mode) fast-lock-mode)
	 (fast-lock-mode -1))
	((and (boundp 'lazy-lock-mode) lazy-lock-mode)
	 (lazy-lock-mode -1))))

;; Do something special for these packages after fontifying.  I prefer a hook.
(defun font-lock-after-fontify-buffer ()
  (cond ((and (boundp 'fast-lock-mode) fast-lock-mode)
	 (fast-lock-after-fontify-buffer))
	((and (boundp 'lazy-lock-mode) lazy-lock-mode)
	 (lazy-lock-after-fontify-buffer))))

;; If the buffer is about to be reverted, it won't be fontified afterward.
(defun font-lock-revert-setup ()
  (setq font-lock-fontified nil))

;; If the buffer has just been reverted, normally that turns off
;; Font Lock mode.  So turn the mode back on if necessary.
(defun font-lock-revert-cleanup ()
  (font-lock-mode 1))

;;;###autoload
(defun font-lock-fontify-buffer ()
  "Fontify the current buffer the way `font-lock-mode' would."
  (interactive)
  (let ((was-on font-lock-mode)
	(verbose (and (or font-lock-verbose (interactive-p))
		      (not (zerop (buffer-size)))))
	(modified (buffer-modified-p)))
    (set (make-local-variable 'font-lock-fontified) nil)
    (if verbose (message "Fontifying %s..." (buffer-name)))
    ;; Turn it on to run hooks and get the right `font-lock-keywords' etc.
    (or was-on (font-lock-set-defaults))
    (condition-case nil
	(save-excursion
	  (if font-lock-no-comments
	      (font-lock-unfontify-region (point-min) (point-max))
	    (font-lock-fontify-region (point-min) (point-max) verbose))
	  (font-lock-hack-keywords (point-min) (point-max) verbose)
	  (setq font-lock-fontified t))
      ;; We don't restore the old fontification, so it's best to unfontify.
      (quit (font-lock-unfontify-region (point-min) (point-max))))
    (if verbose (message "Fontifying %s... %s." (buffer-name)
			 (if font-lock-fontified "done" "aborted")))
    (and (buffer-modified-p)
	 (not modified)
	 (set-buffer-modified-p nil))
    (font-lock-after-fontify-buffer)))

;;; Various information shared by several modes.
;;; Information specific to a single mode should go in its load library.

(defconst lisp-font-lock-keywords-1
  (list
   ;; highlight defining forms.  This doesn't work too nicely for
   ;; (defun (setf foo) ...) but it does work for (defvar foo) which
   ;; is more important.
   (list (concat "^(\\(def\\(const\\|ine-key\\(\\|-after\\)\\|var\\)\\)\\>"
		 "[ \t']*\\([^ \t\n\(\)]+\\)?")
	 '(1 font-lock-keyword-face) '(4 font-lock-variable-name-face nil t))
   (list (concat "^(\\(def[^ \t\n\(\)]+\\|eval-"
		 "\\(a\\(fter-load\\|nd-compile\\)\\|when-compile\\)\\)\\>"
		 "[ \t']*\\([^ \t\n\(\)]+\\)?")
	 '(1 font-lock-keyword-face) '(4 font-lock-function-name-face nil t))
   )
 "Subdued level highlighting Lisp modes.")

(defconst lisp-font-lock-keywords-2
  (append lisp-font-lock-keywords-1
   (let ((word-char "[-+a-zA-Z0-9_:*]"))
     (list
      ;;
      ;; Control structures.  ELisp and CLisp combined.
;    ("cond" "if" "while" "let\\*?" "prog[nv12*]?" "catch" "throw"
;     "save-restriction" "save-excursion" "save-window-excursion"
;     "save-selected-window" "save-match-data" "unwind-protect"
;     "condition-case" "track-mouse"
;     "when" "unless" "do" "flet" "labels" "return" "return-from")
      (cons
       (concat
	"(\\("
	"c\\(atch\\|ond\\(\\|ition-case\\)\\)\\|do\\|flet\\|if\\|"
	"l\\(abels\\|et\\*?\\)\\|prog[nv12*]?\\|return\\(\\|-from\\)\\|"
	"save-\\(excursion\\|match-data\\|restriction\\|"
	"selected-window\\|window-excursion\\)\\|t\\(hrow\\|rack-mouse\\)\\|"
	"un\\(less\\|wind-protect\\)\\|wh\\(en\\|ile\\)"
	"\\)\\>") 1)
      ;;
      ;; Function names in emacs-lisp docstrings (in the syntax that
      ;; `substitute-command-keys' understands).
      (list (concat "\\\\\\\\\\[\\(" word-char "+\\)]")
	    1 font-lock-reference-face t)
      ;;
      ;; Words inside `' which tend to be symbol names.
      (list (concat "`\\(" word-char word-char "+\\)'")
	    1 'font-lock-reference-face t)
      ;;
      ;; CLisp `:' keywords as references.
      (list (concat "\\<:" word-char "+\\>") 0 font-lock-reference-face t)
      ;;
      ;; ELisp and CLisp `&' keywords as types.
      '("\\&\\(optional\\|rest\\|whole\\)\\>" . font-lock-type-face)
      )))
  "Gaudy level highlighting for Lisp modes.")

(defvar lisp-font-lock-keywords lisp-font-lock-keywords-1
  "Default expressions to highlight in Lisp modes.")


(defconst c-font-lock-keywords-1 nil
  "Subdued level highlighting for C modes.")

(defconst c-font-lock-keywords-2 nil
  "Gaudy level highlighting for C modes.")

(defconst c++-font-lock-keywords-1 nil
  "Subdued level highlighting for C++ modes.")

(defconst c++-font-lock-keywords-2 nil
  "Gaudy level highlighting for C++ modes.")

(let ((c-keywords
;      ("break" "continue" "do" "else" "for" "if" "return" "switch" "while")
       "break\\|continue\\|do\\|else\\|for\\|if\\|return\\|switch\\|while")
      (c-type-types
;      ("auto" "extern" "register" "static" "typedef" "struct" "union" "enum"
;	"signed" "unsigned" "short" "long" "int" "char" "float" "double"
;	"void" "volatile" "const")
       (concat "auto\\|c\\(har\\|onst\\)\\|double\\|e\\(num\\|xtern\\)\\|"
	       "float\\|int\\|long\\|register\\|"
	       "s\\(hort\\|igned\\|t\\(atic\\|ruct\\)\\)\\|typedef\\|"
	       "un\\(ion\\|signed\\)\\|vo\\(id\\|latile\\)"))	; 6 ()s deep.
      (c++-keywords
;      ("break" "continue" "do" "else" "for" "if" "return" "switch" "while"
;	"asm" "catch" "delete" "new" "operator" "sizeof" "this" "throw" "try"
;       "protected" "private" "public")
       (concat "asm\\|break\\|c\\(atch\\|ontinue\\)\\|d\\(elete\\|o\\)\\|"
	       "else\\|for\\|if\\|new\\|operator\\|"
	       "p\\(r\\(ivate\\|otected\\)\\|ublic\\)\\|return\\|"
	       "s\\(izeof\\|witch\\)\\|t\\(h\\(is\\|row\\)\\|ry\\)\\|while"))
      (c++-type-types
;      ("auto" "extern" "register" "static" "typedef" "struct" "union" "enum"
;	"signed" "unsigned" "short" "long" "int" "char" "float" "double"
;	"void" "volatile" "const" "class" "inline" "friend" "bool"
;	"virtual" "complex" "template")
       (concat "auto\\|bool\\|c\\(har\\|lass\\|o\\(mplex\\|nst\\)\\)\\|"
	       "double\\|e\\(num\\|xtern\\)\\|f\\(loat\\|riend\\)\\|"
	       "in\\(line\\|t\\)\\|long\\|register\\|"
	       "s\\(hort\\|igned\\|t\\(atic\\|ruct\\)\\)\\|"
	       "t\\(emplate\\|ypedef\\)\\|un\\(ion\\|signed\\)\\|"
	       "v\\(irtual\\|o\\(id\\|latile\\)\\)"))		; 11 ()s deep.
      (ctoken "[a-zA-Z0-9_:~]+"))
 (setq c-font-lock-keywords-1
  (list
   ;;
   ;; Fontify filenames in #include <...> preprocessor directives.
   '("^#[ \t]*include[ \t]+\\(<[^>\"\n]+>\\)" 1 font-lock-string-face)
   ;;
   ;; Fontify function macro names.
   '("^#[ \t]*define[ \t]+\\(\\(\\sw+\\)(\\)" 2 font-lock-function-name-face)
   ;;
   ;; Fontify otherwise as symbol names, and the preprocessor directive names.
   '("^\\(#[ \t]*[a-z]+\\)\\>[ \t]*\\(\\sw+\\)?"
     (1 font-lock-reference-face) (2 font-lock-variable-name-face nil t))
   ;;
   ;; Fontify function name definitions (without type on line).
   (list (concat "^\\(" ctoken "\\)[ \t]*(") 1 'font-lock-function-name-face)
   ))

 (setq c-font-lock-keywords-2
  (append c-font-lock-keywords-1
   (list
    ;;
    ;; Fontify all storage classes and type specifiers (before declarations).
    (cons (concat "\\<\\(" c-type-types "\\)\\>") 'font-lock-type-face)
    ;;
    ;; Fontify variable/structure name declarations and definitions, or
    ;; function name declarations (plus definitions with type on same line).
    (list (concat "\\<\\(" c-type-types "\\)[ \t*]+"
		  "\\(" ctoken "[ \t*]+\\)*"
		  "\\(" ctoken "\\)[ \t]*\\((\\)?")
	  9
	  '(if (match-beginning 10)
	       font-lock-function-name-face
	     font-lock-variable-name-face))
    ;;
    ;; Fontify function/variable name declarations at the start of the line.
    ;; (Not everyone follows the GNU convention of function name at the start.)
    (list (concat "^" ctoken "[ \t*]+"
		  "\\(" ctoken "[ \t*]+\\)*"
		  "\\(" ctoken "\\)[ \t]*\\((\\)?")
	  2
	  '(if (match-beginning 3)
	       font-lock-function-name-face
	     font-lock-variable-name-face))
    ;;
    ;; Fontify variable names declared with structures, or typedef names.
    '("}[ \t*]*\\(\\sw+\\)[ \t]*[;,[]" 1 font-lock-variable-name-face)
    ;;
    ;; Fontify all builtin keywords (except case, default and goto; see below).
    (concat "\\<\\(" c-keywords "\\)\\>")
    ;;
    ;; Fontify case/goto keywords and targets, and goto tags (incl "default:").
    '("\\<\\(case\\|goto\\)\\>[ \t]*\\([^ \t\n:;]+\\)?"
      (1 font-lock-keyword-face) (2 font-lock-reference-face nil t))
    '("^[ \t]*\\(\\sw+\\)[ \t]*:" 1 font-lock-reference-face)
    )))

 (setq c++-font-lock-keywords-1 c-font-lock-keywords-1)
 (setq c++-font-lock-keywords-2
  (append c++-font-lock-keywords-1
   (list
    ;; We don't just add to the C keywords for subtle differences and speed.
    ;; See the above comments for `c-font-lock-keywords-2'.
    (cons (concat "\\<\\(" c++-type-types "\\)\\>") 'font-lock-type-face)
    (list (concat "\\<\\(" c++-type-types "\\)[ \t*&]+"
		  "\\(" ctoken "[ \t*&]+\\)*"
		  "\\(" ctoken "\\)[ \t]*\\((\\)?")
	  14
	  '(if (match-beginning 15)
	       font-lock-function-name-face
	     font-lock-variable-name-face))
    (list (concat "^" ctoken "[ \t*]+"
		  "\\(" ctoken "[ \t*]+\\)*"
		  "\\(" ctoken "\\)[ \t]*\\((\\)?")
	  2
	  '(if (match-beginning 3)
	       font-lock-function-name-face
	     font-lock-variable-name-face))
    '("}[ \t*]*\\(\\sw+\\)[ \t]*[;,[]" 1 font-lock-variable-name-face)
    (concat "\\<\\(" c++-keywords "\\)\\>")
    '("\\<\\(case\\|goto\\)\\>[ \t]*\\([^ \t\n:;]+\\)?"
      (1 font-lock-keyword-face) (2 font-lock-reference-face nil t))
    '("^[ \t]*\\(\\sw+\\)[ \t]*:[^:]" 1 font-lock-reference-face))))
 )

(defvar c-font-lock-keywords c-font-lock-keywords-1
  "Default expressions to highlight in C mode.")

(defvar c++-font-lock-keywords c++-font-lock-keywords-1
  "Default expressions to highlight in C++ mode.")

(defvar tex-font-lock-keywords
  ;; Regexps updated with help from Ulrik Dickow <dickow@nbi.dk>.
  '(("\\\\\\(begin\\|end\\|newcommand\\){\\([a-zA-Z0-9\\*]+\\)}"
     2 font-lock-function-name-face)
    ("\\\\\\(cite\\|label\\|pageref\\|ref\\){\\([^} \t\n]+\\)}"
     2 font-lock-reference-face)
    ;; It seems a bit dubious to use `bold' and `italic' faces since we might
    ;; not be able to display those fonts.
    ("{\\\\bf\\([^}]+\\)}" 1 'bold keep)
    ("{\\\\\\(em\\|it\\|sl\\)\\([^}]+\\)}" 2 'italic keep)
    ("\\\\\\([a-zA-Z@]+\\|.\\)" . font-lock-keyword-face)
    ("^[ \t\n]*\\\\def[\\\\@]\\(\\w+\\)" 1 font-lock-function-name-face keep))
  "Additional expressions to highlight in TeX mode.")

(defun font-lock-choose-keywords (keywords level)
  ;; Return evaled LEVELth element of KEYWORDS.  A LEVEL of nil is equal to a
  ;; LEVEL of 0, a LEVEL of t is equal to (1- (length KEYWORDS)).
  (cond ((symbolp keywords)
	 keywords)
	((numberp level)
	 (or (nth level keywords) (car (reverse keywords))))
	((eq level t)
	 (car (reverse keywords)))
	(t
	 (car keywords))))

(defun font-lock-set-defaults ()
  "Set fontification defaults appropriately for this mode.
Sets `font-lock-keywords', `font-lock-no-comments', `font-lock-syntax-table'
and `font-lock-keywords-case-fold-search' using `font-lock-defaults' (or, if
nil, using `font-lock-defaults-alist') and `font-lock-maximum-decoration'."
  ;; Set face defaults.
  (font-lock-make-faces)
  ;; Set fontification defaults.
  (or font-lock-keywords
      (let ((defaults (or font-lock-defaults
			  (cdr (assq major-mode font-lock-defaults-alist)))))
	;; Keywords?
	(setq font-lock-keywords
	      (font-lock-compile-keywords
	       (eval (font-lock-choose-keywords (nth 0 defaults)
		      font-lock-maximum-decoration))))
	;; Syntactic?
	(if (nth 1 defaults)
	    (set (make-local-variable 'font-lock-no-comments) t))
	;; Case fold?
	(if (nth 2 defaults)
	    (set (make-local-variable 'font-lock-keywords-case-fold-search) t))
	;; Syntax table?
	(if (nth 3 defaults)
	    (let ((slist (nth 3 defaults)))
	      (set (make-local-variable 'font-lock-syntax-table)
		   (copy-syntax-table (syntax-table)))
	      (while slist
		(modify-syntax-entry (car (car slist)) (cdr (car slist))
				     font-lock-syntax-table)
		(setq slist (cdr slist))))))))

;; Install ourselves:

(or (assq 'font-lock-mode minor-mode-alist)
    (setq minor-mode-alist (cons '(font-lock-mode " Font") minor-mode-alist)))

;; Provide ourselves:

(provide 'font-lock)

;;; font-lock.el ends here