:type '(number :tag "seconds")
:group 'jit-lock)
+(defcustom jit-lock-antiblink-grace 2
+ "Like `jit-lock-context-time' but for unterminated multiline strings.
+Setting this to a positive number of seconds helps avoid the
+fontification \"blinking\" behaviour observed when adding
+temporarily unterminated strings to source code. If the user has
+recently created an unterminated string at EOL, allow for an idle
+\"grace\" period to elapse before deciding it is a multi-line
+string and fontifying the remainder of the buffer accordingly."
+ :type '(number :tag "seconds")
+ :group 'jit-lock)
+
(defcustom jit-lock-defer-time nil ;; 0.25
"Idle time after which deferred fontification should take place.
If nil, fontification is not deferred.
"List of buffers with pending deferred fontification.")
(defvar jit-lock-stealth-buffers nil
"List of buffers that are being fontified stealthily.")
+
+(defvar jit-lock--antiblink-grace-timer nil
+ "Idle timer for fontifying unterminated string or comment, or nil")
+(defvar jit-lock--antiblink-l-l-b (make-marker)
+ "Last line beginning (l-l-b) position after last command (a marker).")
+(defvar jit-lock--antiblink-i-s-o-c nil
+ "In string or comment (i-s-o-c) after last command (a boolean).")
+
+
\f
;;; JIT lock mode
(unless jit-lock-context-timer
(setq jit-lock-context-timer
(run-with-idle-timer jit-lock-context-time t
- 'jit-lock-context-fontify)))
+ (lambda ()
+ (unless jit-lock--antiblink-grace-timer
+ (jit-lock-context-fontify))))))
+ (add-hook 'post-command-hook 'jit-lock--antiblink-post-command nil t)
(setq jit-lock-context-unfontify-pos
(or jit-lock-context-unfontify-pos (point-max))))
;; buffer, only jit-lock-context-* will re-fontify it.
(min jit-lock-context-unfontify-pos jit-lock-start))))))
+(defun jit-lock--antiblink-post-command ()
+ (let* ((new-l-l-b (set-marker (make-marker) (line-beginning-position)))
+ (new-i-s-o-c
+ (nth 8 (save-excursion (syntax-ppss (line-end-position)))))
+ (same-line
+ (and jit-lock-antiblink-grace
+ (eq (marker-buffer jit-lock--antiblink-l-l-b) (current-buffer))
+ (= new-l-l-b jit-lock--antiblink-l-l-b))))
+ (cond (;; opened a new multiline string...
+ (and same-line
+
+ (null jit-lock--antiblink-i-s-o-c) new-i-s-o-c)
+ ;; assert that the grace timer is null and schedule it
+ (when jit-lock--antiblink-grace-timer
+ (display-warning
+ 'font-lock :level
+ "`jit-lock--antiblink-grace-timer' not null" :warning))
+ (setq jit-lock--antiblink-grace-timer
+ (run-with-idle-timer jit-lock-antiblink-grace nil
+ (lambda ()
+ (jit-lock-context-fontify)
+ (setq jit-lock--antiblink-grace-timer nil)))))
+ (;; closed an unterminated multiline string.
+ (and same-line
+ (null new-i-s-o-c) jit-lock--antiblink-i-s-o-c)
+ ;; Kill the grace timer, might already have run and died.
+ ;; Don't refontify immediately: it adds an unreasonable
+ ;; delay to a well-behaved operation. Leave it for the
+ ;; `jit-lock-context-timer' as usual.
+ (when jit-lock--antiblink-grace-timer
+ (cancel-timer jit-lock--antiblink-grace-timer)
+ (setq jit-lock--antiblink-grace-timer nil))
+
+ )
+ (same-line
+ ;; in same line, but no state change, leave everything as it was
+ )
+ (t
+ ;; left the line somehow or customized feature away, etc
+ ;; kill timer if running, resume normal operation.
+ (when jit-lock--antiblink-grace-timer
+ ;; Do refontify immediately, adding a small delay. This
+ ;; is per Lars' request, and it makes sense because we
+ ;; should remark somehow that we are leaving the unstable
+ ;; state.
+ (jit-lock-context-fontify)
+ (cancel-timer jit-lock--antiblink-grace-timer)
+ (setq jit-lock--antiblink-grace-timer nil))))
+ ;; update variables
+ (setq jit-lock--antiblink-l-l-b new-l-l-b
+ jit-lock--antiblink-i-s-o-c new-i-s-o-c)))
+
(provide 'jit-lock)
;;; jit-lock.el ends here