settings. See the variable `font-lock-defaults', which takes precedence.")
(make-obsolete-variable 'font-lock-defaults-alist 'font-lock-defaults)
+(defvar font-lock-extend-region-function nil
+ "A function that determines the region to fontify after a change.
+
+This buffer-local variable is either nil, or is a function that determines the
+region to fontify. It is usually set by the major mode. The currently active
+font-lock after-change function calls this function after each buffer change.
+
+The function is given three parameters, the standard BEG, END, and OLD-LEN
+from after-change-functions. It should return either a cons of the beginning
+and end buffer positions \(in that order) of the region to fontify, or nil
+\(which directs the caller to fontify a default region). This function need
+not preserve point or the match-data, but must preserve the current
+restriction. The region it returns may start or end in the middle of a
+line.")
+(make-variable-buffer-local 'font-lock-extend-region-function)
+
+(defun font-lock-extend-region (beg end old-len)
+ "Determine the region to fontify after a buffer change.
+
+BEG END and OLD-LEN are the standard parameters from after-change-functions.
+The return value is either nil \(which directs the caller to chose the region
+itself), or a cons of the beginning and end \(in that order) of the region.
+The region returned may start or end in the middle of a line."
+ (if font-lock-extend-region-function
+ (save-match-data
+ (save-excursion
+ (funcall font-lock-extend-region-function beg end old-len)))))
+
(defvar font-lock-function 'font-lock-default-function
"A function which is called when `font-lock-mode' is toggled.
It will be passed one argument, which is the current value of
(when font-lock-syntax-table
(set-syntax-table font-lock-syntax-table))
(goto-char beg)
- (setq beg (line-beginning-position (- 1 font-lock-lines-before)))
+ (setq beg (line-beginning-position))
;; check to see if we should expand the beg/end area for
;; proper multiline matches
(when (and (> beg (point-min))
;; Called when any modification is made to buffer text.
(defun font-lock-after-change-function (beg end old-len)
(let ((inhibit-point-motion-hooks t)
- (inhibit-quit t))
+ (inhibit-quit t)
+ (region (font-lock-extend-region beg end old-len)))
(save-excursion
(save-match-data
- ;; Rescan between start of lines enclosing the region.
- (font-lock-fontify-region
- (progn (goto-char beg) (forward-line 0) (point))
- (progn (goto-char end) (forward-line 1) (point)))))))
+ (if region
+ ;; Fontify the region the major mode has specified.
+ (setq beg (car region) end (cdr region))
+ ;; Fontify the whole lines which enclose the region.
+ (setq beg (progn (goto-char beg)
+ (forward-line (- font-lock-lines-before)))
+ end (progn (goto-char end) (forward-line 1) (point))))
+ (font-lock-fontify-region beg end)))))
(defun font-lock-fontify-block (&optional arg)
"Fontify some lines the way `font-lock-fontify-buffer' would.
in case the syntax of those lines has changed. Refontification
will take place when text is fontified stealthily."
(when (and jit-lock-mode (not memory-full))
- (save-excursion
- (with-buffer-prepared-for-jit-lock
- ;; It's important that the `fontified' property be set from the
- ;; beginning of the line, else font-lock will properly change the
- ;; text's face, but the display will have been done already and will
- ;; be inconsistent with the buffer's content.
- (goto-char start)
- (setq start (line-beginning-position))
-
- ;; If we're in text that matches a multi-line font-lock pattern,
- ;; make sure the whole text will be redisplayed.
- ;; I'm not sure this is ever necessary and/or sufficient. -stef
- (when (get-text-property start 'font-lock-multiline)
- (setq start (or (previous-single-property-change
- start 'font-lock-multiline)
- (point-min))))
-
- ;; Make sure we change at least one char (in case of deletions).
- (setq end (min (max end (1+ start)) (point-max)))
- ;; Request refontification.
- (put-text-property start end 'fontified nil))
- ;; Mark the change for deferred contextual refontification.
- (when jit-lock-context-unfontify-pos
- (setq jit-lock-context-unfontify-pos
- ;; Here we use `start' because nothing guarantees that the
- ;; text between start and end will be otherwise refontified:
- ;; usually it will be refontified by virtue of being
- ;; displayed, but if it's outside of any displayed area in the
- ;; buffer, only jit-lock-context-* will re-fontify it.
- (min jit-lock-context-unfontify-pos start))))))
+ (let ((region (font-lock-extend-region start end old-len)))
+ (save-excursion
+ (with-buffer-prepared-for-jit-lock
+ ;; It's important that the `fontified' property be set from the
+ ;; beginning of the line, else font-lock will properly change the
+ ;; text's face, but the display will have been done already and will
+ ;; be inconsistent with the buffer's content.
+ ;;
+ ;; FIXME!!! (Alan Mackenzie, 2006-03-14): If start isn't at a BOL,
+ ;; expanding the region to BOL might mis-fontify, should the BOL not
+ ;; be at a "safe" position.
+ (setq start (if region
+ (car region)
+ (goto-char start)
+ (line-beginning-position (- 1 font-lock-lines-before))))
+
+ ;; If we're in text that matches a multi-line font-lock pattern,
+ ;; make sure the whole text will be redisplayed.
+ ;; I'm not sure this is ever necessary and/or sufficient. -stef
+ (when (get-text-property start 'font-lock-multiline)
+ (setq start (or (previous-single-property-change
+ start 'font-lock-multiline)
+ (point-min))))
+
+ (if region (setq end (cdr region)))
+ ;; Make sure we change at least one char (in case of deletions).
+ (setq end (min (max end (1+ start)) (point-max)))
+ ;; Request refontification.
+ (put-text-property start end 'fontified nil))
+ ;; Mark the change for deferred contextual refontification.
+ (when jit-lock-context-unfontify-pos
+ (setq jit-lock-context-unfontify-pos
+ ;; Here we use `start' because nothing guarantees that the
+ ;; text between start and end will be otherwise refontified:
+ ;; usually it will be refontified by virtue of being
+ ;; displayed, but if it's outside of any displayed area in the
+ ;; buffer, only jit-lock-context-* will re-fontify it.
+ (min jit-lock-context-unfontify-pos start)))))))
(provide 'jit-lock)
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