-;;; paren.el --- highlight matching paren.
-;; Copyright (C) 1993 Free Software Foundation, Inc.
+;;; paren.el --- highlight matching paren
+
+;; Copyright (C) 1993, 1996, 2001, 2002, 2003, 2004,
+;; 2005 Free Software Foundation, Inc.
+
+;; Author: rms@gnu.org
+;; Maintainer: FSF
+;; Keywords: languages, faces
;; This file is part of GNU Emacs.
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
-;; along with GNU Emacs; see the file COPYING. If not, write to
-;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+;; along with GNU Emacs; see the file COPYING. If not, write to the
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
;;; Commentary:
-;; Load this and it will display highlighting on whatever
-;; paren matches the one before or after point.
+;; Put this into your ~/.emacs:
+
+;; (show-paren-mode t)
+
+;; It will display highlighting on whatever paren matches the one
+;; before or after point.
;;; Code:
+(defgroup paren-showing nil
+ "Showing (un)matching of parens and expressions."
+ :prefix "show-paren-"
+ :group 'paren-matching)
+
+;; 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)
+
+(defcustom show-paren-style 'parenthesis
+ "*Style used when showing a matching paren.
+Valid styles are `parenthesis' (meaning show the matching paren),
+`expression' (meaning show the entire expression enclosed by the paren) and
+`mixed' (meaning show the matching paren if it is visible, and the expression
+otherwise)."
+ :type '(choice (const parenthesis) (const expression) (const mixed))
+ :group 'paren-showing)
+
+(defcustom show-paren-delay
+ (if (featurep 'lisp-float-type) (/ (float 1) (float 8)) 1)
+ "*Time in seconds to delay before showing a matching paren."
+ :type '(number :tag "seconds")
+ :group 'paren-showing)
+
+(defcustom show-paren-priority 1000
+ "*Priority of paren highlighting overlays."
+ :type 'integer
+ :group 'paren-showing
+ :version "21.1")
+
+(defcustom show-paren-ring-bell-on-mismatch nil
+ "*If non-nil, beep if mismatched paren is detected."
+ :type 'boolean
+ :group 'paren-showing
+ :version "20.3")
+
+(defgroup paren-showing-faces nil
+ "Group for faces of Show Paren mode."
+ :group 'paren-showing
+ :group 'faces
+ :version "22.1")
+
+(defface show-paren-match
+ '((((class color) (background light))
+ :background "turquoise") ; looks OK on tty (becomes cyan)
+ (((class color) (background dark))
+ :background "steelblue3") ; looks OK on tty (becomes blue)
+ (((background dark))
+ :background "grey50")
+ (t
+ :background "gray"))
+ "Show Paren mode face used for a matching paren."
+ :group 'paren-showing-faces)
+;; backward-compatibility alias
+(put 'show-paren-match-face 'face-alias 'show-paren-match)
+
+(defface show-paren-mismatch
+ '((((class color)) (:foreground "white" :background "purple"))
+ (t (:inverse-video t)))
+ "Show Paren mode face used for a mismatching paren."
+ :group 'paren-showing-faces)
+;; backward-compatibility alias
+(put 'show-paren-mismatch-face 'face-alias 'show-paren-mismatch)
+
+(defvar show-paren-highlight-openparen t
+ "*Non-nil turns on openparen highlighting when matching forward.")
+
+(defvar show-paren-idle-timer nil)
+
+;;;###autoload
+(define-minor-mode show-paren-mode
+ "Toggle Show Paren mode.
+With prefix ARG, turn Show Paren mode on if and only if ARG is positive.
+Returns the new status of Show Paren mode (non-nil means on).
+
+When Show Paren mode is enabled, any matching parenthesis is highlighted
+in `show-paren-style' after `show-paren-delay' seconds of Emacs idle time."
+ :global t :group 'paren-showing
+ ;; Enable or disable the mechanism.
+ ;; First get rid of the old idle timer.
+ (if show-paren-idle-timer
+ (cancel-timer show-paren-idle-timer))
+ (setq show-paren-idle-timer nil)
+ ;; If show-paren-mode is enabled in some buffer now,
+ ;; set up a new timer.
+ (when (memq t (mapcar (lambda (buffer)
+ (with-current-buffer buffer
+ show-paren-mode))
+ (buffer-list)))
+ (setq show-paren-idle-timer (run-with-idle-timer
+ show-paren-delay t
+ 'show-paren-function)))
+ (unless show-paren-mode
+ (and show-paren-overlay
+ (eq (overlay-buffer show-paren-overlay) (current-buffer))
+ (delete-overlay show-paren-overlay))
+ (and show-paren-overlay-1
+ (eq (overlay-buffer show-paren-overlay-1) (current-buffer))
+ (delete-overlay show-paren-overlay-1))))
;; Find the place to show, if there is one,
;; and show it until input arrives.
-(defun show-paren-command-hook ()
- (let (pos dir mismatch (oldpos (point))
- (face (if (face-equal 'highlight 'region)
- 'underline 'highlight)))
- (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
- (setq pos nil))))
- (cond (pos
- (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)))
- )
- (t
- (and show-paren-overlay (overlay-buffer show-paren-overlay)
- (delete-overlay show-paren-overlay))))))
-
-(add-hook 'post-command-hook 'show-paren-command-hook)
+(defun show-paren-function ()
+ (if show-paren-mode
+ (let ((oldpos (point))
+ (dir (cond ((eq (syntax-class (syntax-after (1- (point)))) 5) -1)
+ ((eq (syntax-class (syntax-after (point))) 4) 1)))
+ pos mismatch face)
+ ;;
+ ;; Find the other end of the sexp.
+ (when dir
+ (save-excursion
+ (save-restriction
+ ;; Determine the range within which to look for a match.
+ (when 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.
+ ;; Errors or nil mean there is a mismatch.
+ (condition-case ()
+ (setq pos (scan-sexps (point) dir))
+ (error (setq pos t mismatch t)))
+ ;; Move back the other way and verify we get back to the
+ ;; starting point. If not, these two parens don't really match.
+ ;; Maybe the one at point is escaped and doesn't really count.
+ (when (integerp pos)
+ (unless (condition-case ()
+ (eq (point) (scan-sexps pos (- dir)))
+ (error nil))
+ (setq pos nil)))
+ ;; If found a "matching" paren, see if it is the right
+ ;; kind of paren to match the one we started at.
+ (when (integerp pos)
+ (let ((beg (min pos oldpos)) (end (max pos oldpos)))
+ (unless (eq (syntax-class (syntax-after beg)) 8)
+ (setq mismatch
+ (not (or (eq (char-before end)
+ ;; This can give nil.
+ (cdr (syntax-after beg)))
+ (eq (char-after beg)
+ ;; This can give nil.
+ (cdr (syntax-after (1- end))))
+ ;; The cdr might hold a new paren-class
+ ;; info rather than a matching-char info,
+ ;; in which case the two CDRs should match.
+ (eq (cdr (syntax-after (1- end)))
+ (cdr (syntax-after beg))))))))))))
+ ;;
+ ;; Highlight the other end of the sexp, or unhighlight if none.
+ (if (not pos)
+ (progn
+ ;; 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))
+ (and show-paren-overlay-1 (overlay-buffer show-paren-overlay-1)
+ (delete-overlay show-paren-overlay-1)))
+ ;;
+ ;; Use the correct face.
+ (if mismatch
+ (progn
+ (if show-paren-ring-bell-on-mismatch
+ (beep))
+ (setq face 'show-paren-mismatch))
+ (setq face 'show-paren-match))
+ ;;
+ ;; If matching backwards, highlight the closeparen
+ ;; before point as well as its matching open.
+ ;; If matching forward, and the openparen is unbalanced,
+ ;; highlight the paren at point to indicate misbalance.
+ ;; Otherwise, turn off any such highlighting.
+ (if (and (not show-paren-highlight-openparen) (= dir 1) (integerp pos))
+ (when (and show-paren-overlay-1
+ (overlay-buffer show-paren-overlay-1))
+ (delete-overlay show-paren-overlay-1))
+ (let ((from (if (= dir 1)
+ (point)
+ (forward-point -1)))
+ (to (if (= dir 1)
+ (forward-point 1)
+ (point))))
+ (if show-paren-overlay-1
+ (move-overlay show-paren-overlay-1 from to (current-buffer))
+ (setq show-paren-overlay-1 (make-overlay from to)))
+ ;; Always set the overlay face, since it varies.
+ (overlay-put show-paren-overlay-1 'priority show-paren-priority)
+ (overlay-put show-paren-overlay-1 'face face)))
+ ;;
+ ;; Turn on highlighting for the matching paren, if found.
+ ;; If it's an unmatched paren, turn off any such highlighting.
+ (unless (integerp pos)
+ (delete-overlay show-paren-overlay))
+ (let ((to (if (or (eq show-paren-style 'expression)
+ (and (eq show-paren-style 'mixed)
+ (not (pos-visible-in-window-p pos))))
+ (point)
+ pos))
+ (from (if (or (eq show-paren-style 'expression)
+ (and (eq show-paren-style 'mixed)
+ (not (pos-visible-in-window-p pos))))
+ pos
+ (save-excursion
+ (goto-char pos)
+ (forward-point (- dir))))))
+ (if show-paren-overlay
+ (move-overlay show-paren-overlay from to (current-buffer))
+ (setq show-paren-overlay (make-overlay from to))))
+ ;;
+ ;; Always set the overlay face, since it varies.
+ (overlay-put show-paren-overlay 'priority show-paren-priority)
+ (overlay-put show-paren-overlay 'face face)))
+ ;; show-paren-mode is nil in this buffer.
+ (and show-paren-overlay
+ (delete-overlay show-paren-overlay))
+ (and show-paren-overlay-1
+ (delete-overlay show-paren-overlay-1))))
+
+(provide 'paren)
+;; arch-tag: d0969b88-7ac0-4bd0-bd53-e73b892b86a9
+;;; paren.el ends here