master e4b1445f43: CC Mode. Make AWK Mode work with electric-pair-mode

[Alan Mackenzie]

branch: master
commit e4b1445f4301a4a672442d29f93983d804a80982
Author: Alan Mackenzie <acm@muc.de>
Commit: Alan Mackenzie <acm@muc.de>

    CC Mode.  Make AWK Mode work with electric-pair-mode
    
    Also fix some minor anomalies with other CC Mode modes in 
electric-pair-mode.
    This fixes bug #53446.
    
    * lisp/progmodes/cc-mode.el (c-open-string-opener): New buffer local
    variable.
    (c-after-change-mark-abnormal-strings): Set c-open-string-opener when an
    unbalanced string is detected.
    (c-before-change): Initilize c-open-string-opener to nil, each buffer 
change.
    (c-electric-pair-inhibit-predicate): Use the value of c-open-string-opener 
to
    flag an unbalaced string rather than trying to calculate it again.
    
    * lisp/progmodes/cc-awk.el (c-awk-syntax-tablify-string): Set
    c-open-string-opener when an unbalanced string is detected.
---
 lisp/progmodes/cc-awk.el  | 25 +++++++++++++++----------
 lisp/progmodes/cc-mode.el | 27 +++++++++++++++------------
 2 files changed, 30 insertions(+), 22 deletions(-)

diff --git a/lisp/progmodes/cc-awk.el b/lisp/progmodes/cc-awk.el
index 57750a2b39..089fa9ffe4 100644
--- a/lisp/progmodes/cc-awk.el
+++ b/lisp/progmodes/cc-awk.el
@@ -56,6 +56,7 @@
 ;; Silence the byte compiler.
 (cc-bytecomp-defvar c-new-BEG)
 (cc-bytecomp-defvar c-new-END)
+(cc-bytecomp-defvar c-open-string-opener)
 (cc-bytecomp-defun c-restore-string-fences)
 (cc-bytecomp-defun c-clear-string-fences)
 
@@ -777,16 +778,20 @@
   ;; opener, t if it would be a division sign.
   ;;
   ;; This function does hidden buffer changes.
-  (search-forward-regexp c-awk-string-without-end-here-re nil t) ; a (possibly 
unterminated) string
-  (c-awk-set-string-regexp-syntax-table-properties
-   (match-beginning 0) (match-end 0))
-  (cond ((looking-at "\"")
-         (forward-char)
-         t)                             ; In AWK, ("15" / 5) gives 3 ;-)
-        ((looking-at "[\n\r]")          ; Unterminated string with EOL.
-         (forward-char)
-         nil)                           ; / on next line would start a regexp
-        (t nil)))                       ; Unterminated string at EOB
+  (let ((string-start (if (eq (char-after) ?_) (1+ (point)) (point))))
+    (search-forward-regexp c-awk-string-without-end-here-re nil t) ; a 
(possibly unterminated) string
+    (c-awk-set-string-regexp-syntax-table-properties
+     (match-beginning 0) (match-end 0))
+    (cond ((looking-at "\"")
+          (forward-char)
+          t)                           ; In AWK, ("15" / 5) gives 3 ;-)
+         ((looking-at "[\n\r]")        ; Unterminated string with EOL.
+          (setq c-open-string-opener string-start)
+          (forward-char)
+          nil)                         ; / on next line would start a regexp
+         (t                            ; Unterminated string at EOB
+          (setq c-open-string-opener string-start)
+          nil))))
 
 (defun c-awk-syntax-tablify-/ (anchor anchor-state-/div)
   ;; Point is at a /.  Determine whether this is a division sign or a regexp
diff --git a/lisp/progmodes/cc-mode.el b/lisp/progmodes/cc-mode.el
index 9309a546db..15dfdc4b0e 100644
--- a/lisp/progmodes/cc-mode.el
+++ b/lisp/progmodes/cc-mode.el
@@ -1421,6 +1421,13 @@ Note that the style variables are always made local to 
the buffer."
       (c-clear-syn-tab (point)))
      (t (c-benign-error "c-remove-string-fences: Wrong position")))))
 
+(defvar c-open-string-opener nil
+  "The position of the opening delimiter of an unterminated string or nil.
+This is valid only immediately after a buffer change, and refers
+only to an opener in the (logical) line containing the END
+position of `after-change-functions'.")
+(make-variable-buffer-local 'c-open-string-opener)
+
 (defun c-before-change-check-unbalanced-strings (beg end)
   ;; If BEG or END is inside an unbalanced string, remove the syntax-table
   ;; text property from respectively the start or end of the string.  Also
@@ -1685,13 +1692,14 @@ Note that the style variables are always made local to 
the buffer."
            (c-put-syn-tab (1- (point)) '(15))
            (c-put-syn-tab (match-end 0) '(15))
            (setq c-new-BEG (min c-new-BEG (point))
-                 c-new-END (max c-new-END (match-end 0))))
+                 c-new-END (max c-new-END (match-end 0)))
+           (setq c-open-string-opener (1- (point))))
           ((or (eq (match-end 0) (point-max))
                (eq (char-after (match-end 0)) ?\\)) ; \ at EOB
            (c-put-syn-tab (1- (point)) '(15))
            (setq c-new-BEG (min c-new-BEG (point))
                  c-new-END (max c-new-END (match-end 0))) ; Do we need 
c-new-END?
-           ))
+           (setq c-open-string-opener (1- (point)))))
          (goto-char (min (1+ (match-end 0)) (point-max))))
        (setq s nil)))))
 
@@ -2130,6 +2138,7 @@ with // and /*, not more generic line and block comments."
        ;; (c-new-BEG c-new-END) will be the region to fontify.
        (setq c-new-BEG beg  c-new-END end)
        (setq c-maybe-stale-found-type nil)
+       (setq c-open-string-opener nil)
        ;; A workaround for syntax-ppss's failure to notice syntax-table text
        ;; property changes.
        (when (fboundp 'syntax-ppss)
@@ -2698,11 +2707,9 @@ This function is called from `c-common-init', once per 
mode initialization."
 At the time of call, point is just after the newly inserted CHAR.
 
 When CHAR is \" and not within a comment, t will be returned if
-the quotes on the current line are already balanced (i.e. if the
-last \" is not marked with a string fence syntax-table text
-property).  For other cases, the default value of
-`electric-pair-inhibit-predicate' is called and its value
-returned.
+the quotes on the current line are already balanced.  For other
+cases, the default value of `electric-pair-inhibit-predicate' is
+called and its value returned.
 
 This function is the appropriate value of
 `electric-pair-inhibit-predicate' for CC Mode modes, which mark
@@ -2710,11 +2717,7 @@ invalid strings with such a syntax table text property 
on the
 opening \" and the next unescaped end of line."
   (if (and (eq char ?\")
           (not (memq (cadr (c-semi-pp-to-literal (1- (point)))) '(c c++))))
-      (let ((last-quote (save-match-data
-                         (save-excursion
-                           (goto-char (c-point 'eoll))
-                           (search-backward "\"")))))
-       (not (equal (c-get-char-property last-quote 'c-fl-syn-tab) '(15))))
+      (not c-open-string-opener)
     (funcall (default-value 'electric-pair-inhibit-predicate) char)))