Tweak jit-lock-antiblink-grace's docs and code style

* lisp/jit-lock.el (jit-lock-antiblink-grace): Adjust docstring.
(jit-lock--antiblink-line-beginning-position)
(jit-lock--antiblink-string-or-comment): Rename from
jit-lock--antiblink-l-b-p, jit-lock--antiblink-i-s-o-c.
(jit-lock--antiblink-post-command): Use new variables.  Don't
message.

* etc/NEWS (jit-lock-antiblink-grace): Adjust entry.

diff --git a/etc/NEWS b/etc/NEWS
index de1c00fc6f75c6c6dd95696e709ebc2f6dcd1fde..bcec4664eda166baed6e8641f059bbc267894fad 100644 (file)
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -627,13 +627,10 @@ region.  When there's no active region, the command works on the
 current and the previous or the next line, as before.
 
 ---
-** New customizable variable 'jit-lock-antiblink-grace'
-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, jit fontification allows this idle
-"grace" period to elapse before deciding it is a multi-line string and
-fontifying the remainder of the buffer accordingly.
+** New customizable variable 'jit-lock-antiblink-grace'.
+When adding strings to source code, this helps avoid
+\"blinking\", an unwanted oscillation of certain regions between
+string and non-string fontification.
 
 
 \f

diff --git a/lisp/jit-lock.el b/lisp/jit-lock.el
index 733fcdd3ed00f59e4326ec8244b4de9cd9f8c85f..23afb53bf848778a0c4379e67870451601b9b966 100644 (file)
--- a/lisp/jit-lock.el
+++ b/lisp/jit-lock.el
@@ -124,13 +124,16 @@ The value of this variable is used when JIT Lock mode is turned on."
   :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."
+  "Idle time after which to refontify due to unterminated strings.
+If the user creates a temporarily unterminated string up to the
+end of the current line, that part of the line is fontified after
+`jit-lock-context-time', but an extended idle \"grace\" period of
+this many seconds is granted before deciding it is a multi-line
+string and fontifying the remainder of the buffer accordingly.
+When adding strings to source code, this helps avoid
+\"blinking\", an unwanted oscillation of certain regions between
+string and non-string fontification.  If nil, there is no grace
+period."
   :type '(number :tag "seconds")
   :group 'jit-lock)
 
@@ -171,10 +174,10 @@ If nil, contextual fontification is disabled.")
 
 (defvar jit-lock--antiblink-grace-timer nil
   "Idle timer for fontifying unterminated string or comment, or nil.")
-(defvar jit-lock--antiblink-l-b-p (make-marker)
-  "Last line beginning position (l-b-p) 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).")
+(defvar jit-lock--antiblink-line-beginning-position (make-marker)
+  "Last line beginning position after last command (a marker).")
+(defvar jit-lock--antiblink-string-or-comment nil
+  "Non-nil if in string or comment after last command (a boolean).")
 
 
 \f
@@ -698,25 +701,24 @@ will take place when text is fontified stealthily."
          (same-line
           (and jit-lock-antiblink-grace
                (not (= new-l-b-p l-b-p-2))
-               (eq (marker-buffer jit-lock--antiblink-l-b-p) (current-buffer))
-               (= new-l-b-p jit-lock--antiblink-l-b-p)))
-         (new-i-s-o-c
+               (eq (marker-buffer jit-lock--antiblink-line-beginning-position)
+                   (current-buffer))
+               (= new-l-b-p jit-lock--antiblink-line-beginning-position)))
+         (new-s-o-c
           (and same-line
                (nth 8 (save-excursion (syntax-ppss l-b-p-2))))))
     (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
-             (message "internal warning: `jit-lock--antiblink-grace-timer' not null"))
+                (null jit-lock--antiblink-string-or-comment) new-s-o-c)
            (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)))))
+                                        (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)
+                (null new-s-o-c) jit-lock--antiblink-string-or-comment)
            ;; 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
@@ -739,8 +741,8 @@ will take place when text is fontified stealthily."
              (cancel-timer jit-lock--antiblink-grace-timer)
              (setq jit-lock--antiblink-grace-timer nil))))
     ;; update variables
-    (setq jit-lock--antiblink-l-b-p   new-l-b-p
-          jit-lock--antiblink-i-s-o-c new-i-s-o-c)))
+    (setq jit-lock--antiblink-line-beginning-position   new-l-b-p
+          jit-lock--antiblink-string-or-comment new-s-o-c)))
 
 (provide 'jit-lock)