Enable the hook only if window-system.

Clear blink-paren-function at the same time.
(show-paren-command-hook): If after a closeparen,
highlight that closeparen as well as matching open.
Use a different color for a mismatch, if color screen.

diff --git a/lisp/paren.el b/lisp/paren.el
index 221c6aaf5d4c279ddfa2f98d4e62ed40c32245c1..c96efcd1863a5a259c1fba49a0da4eb875672d88 100644 (file)
--- a/lisp/paren.el
+++ b/lisp/paren.el
@@ -28,69 +28,96 @@
 
 ;;; Code:
 
+;; This is the overlay used to highlight the matching paren.
 (defvar show-paren-overlay nil)
+;; This is the overlay used to highlight the closeparen
+;; right before point.
+(defvar show-paren-overlay-1 nil)
+
+(defvar show-paren-mismatch-face nil)
 
 ;; Find the place to show, if there is one,
 ;; and show it until input arrives.
 (defun show-paren-command-hook ()
   (if window-system
       (let (pos dir mismatch (oldpos (point))
-               (face (if (face-equal 'highlight 'region)
-                         'underline 'highlight)))
+               (face 'region))
        (cond ((eq (char-syntax (following-char)) ?\()
               (setq dir 1))
              ((eq (char-syntax (preceding-char)) ?\))
               (setq dir -1)))
-       (save-excursion
-         (save-restriction
-           ;; Determine the range within which to look for a match.
-           (if blink-matching-paren-distance
-               (narrow-to-region (max (point-min)
-                                      (- (point) blink-matching-paren-distance))
-                                 (min (point-max)
-                                      (+ (point) blink-matching-paren-distance))))
-           ;; Scan across one sexp within that range.
-           (condition-case ()
-               (setq pos (scan-sexps (point) dir))
-             (error nil))
-           ;; See if the "matching" paren is the right kind of paren
-           ;; to match the one we started at.
-           (if pos
-               (let ((beg (min pos oldpos)) (end (max pos oldpos)))
-                 (and (/= (char-syntax (char-after beg)) ?\$)
-                      (setq mismatch
-                            (/= (char-after (1- end))
-                                (logand (lsh (aref (syntax-table)
-                                                   (char-after beg))
-                                             -8)
-                                        255))))))
-           ;; If they don't properly match, don't show.
-           (if mismatch
-               (progn
-                 (message "Paren mismatch")
-    ;;;              (setq pos nil)
-                 ))))
+       (if dir
+           (save-excursion
+             (save-restriction
+               ;; Determine the range within which to look for a match.
+               (if blink-matching-paren-distance
+                   (narrow-to-region (max (point-min)
+                                          (- (point) blink-matching-paren-distance))
+                                     (min (point-max)
+                                          (+ (point) blink-matching-paren-distance))))
+               ;; Scan across one sexp within that range.
+               (condition-case ()
+                   (setq pos (scan-sexps (point) dir))
+                 (error nil))
+               ;; See if the "matching" paren is the right kind of paren
+               ;; to match the one we started at.
+               (if pos
+                   (let ((beg (min pos oldpos)) (end (max pos oldpos)))
+                     (and (/= (char-syntax (char-after beg)) ?\$)
+                          (setq mismatch
+                                (/= (char-after (1- end))
+                                    (logand (lsh (aref (syntax-table)
+                                                       (char-after beg))
+                                                 -8)
+                                            255))))))
+               ;; If they don't properly match, use a different face,
+               ;; or print a message.
+               (if mismatch
+                   (progn
+                     (and (null show-paren-mismatch-face)
+                          (x-display-color-p)
+                          (or (setq show-paren-mismatch-face
+                                    (internal-find-face 'paren-mismatch))
+                              (progn
+                                (setq show-paren-mismatch-face
+                                      (make-face 'paren-mismatch))
+                                (set-face-background 'paren-mismatch 'purple))))
+                     (if show-paren-mismatch-face
+                         (setq face show-paren-mismatch-face)
+                       (message "Paren mismatch"))))
+               )))
        (cond (pos
+              (if (= dir -1)
+                  ;; If matching backwards, highlight the closeparen
+                  ;; before point as well as its matching open.
+                  (progn
+                    (if show-paren-overlay-1
+                        (move-overlay show-paren-overlay-1 (+ (point) dir) (point))
+                      (setq show-paren-overlay-1
+                            (make-overlay (- pos dir) pos)))
+                    (overlay-put show-paren-overlay-1 'face face))
+                ;; Otherwise, turn off any such highlighting.
+                (and show-paren-overlay-1
+                     (overlay-buffer show-paren-overlay-1)
+                     (delete-overlay show-paren-overlay-1)))
+              ;; Turn on highlighting for the matching paren.
               (if show-paren-overlay
                   (move-overlay show-paren-overlay (- pos dir) pos)
                 (setq show-paren-overlay
                       (make-overlay (- pos dir) pos)))
-              (overlay-put show-paren-overlay 'face face)
-    ;;; This is code to blink the highlighting.
-    ;;; It is desirable to avoid this because
-    ;;; it would interfere with auto-save and gc when idle.
-;;;       (while (sit-for 1)
-;;;         (overlay-put show-paren-overlay
-;;;                      'face
-;;;                      (if (overlay-get show-paren-overlay
-;;;                                       'face)
-;;;                          nil face)))
-              )
+              (overlay-put show-paren-overlay 'face face))
              (t
+              ;; If not at a paren that has a match,
+              ;; turn off any previous paren highlighting.
               (and show-paren-overlay (overlay-buffer show-paren-overlay)
-                   (delete-overlay show-paren-overlay)))))))
+                   (delete-overlay show-paren-overlay))
+              (and show-paren-overlay-1 (overlay-buffer show-paren-overlay-1)
+                   (delete-overlay show-paren-overlay-1)))))))
 
-(add-hook 'post-command-hook 'show-paren-command-hook)
+(if window-system
+    (progn
+      (setq blink-paren-function nil)
+      (add-hook 'post-command-hook 'show-paren-command-hook)))
 
 (provide 'paren)