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|
;;; paren.el --- highlight matching paren.
;; Copyright (C) 1993, 1996 Free Software Foundation, Inc.
;; Author: rms@gnu.ai.mit.edu
;; Maintainer: FSF
;; Keywords: languages, faces
;; This file is part of GNU Emacs.
;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; 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, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;;; Commentary:
;; Load this and it will display highlighting on whatever
;; paren matches the one before or after point.
;;; 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-mode nil)
(defvar show-paren-idle-timer nil)
(defvar show-paren-mismatch-face nil)
(defvar show-paren-delay (if (featurep 'lisp-float-type) 0.125 1)
"*Time in seconds to delay before showing the matching paren.")
(defvar show-paren-face 'region
"*Name of the face to use for showing the matching paren.")
;;;###autoload
(defun show-paren-mode (&optional arg)
"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
after `show-paren-delay' seconds of Emacs idle time."
(interactive "P")
(if window-system
(let ((on-p (if arg
(> (prefix-numeric-value arg) 0)
(not show-paren-mode))))
(setq blink-matching-paren-on-screen (not on-p))
(and show-paren-idle-timer (cancel-timer show-paren-idle-timer))
(if on-p
(setq show-paren-idle-timer (run-with-idle-timer show-paren-delay t
'show-paren-function))
(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)))
(setq show-paren-mode on-p))))
;; Find the place to show, if there is one,
;; and show it until input arrives.
(defun show-paren-function ()
;; Do nothing if no window system to display results with.
;; Do nothing if executing keyboard macro.
;; Do nothing if input is pending.
(if window-system
(let (pos dir mismatch (oldpos (point))
(face show-paren-face))
(cond ((eq (char-syntax (preceding-char)) ?\))
(setq dir -1))
((eq (char-syntax (following-char)) ?\()
(setq dir 1)))
(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.
;; Errors or nil mean there is a mismatch.
(condition-case ()
(setq pos (scan-sexps (point) dir))
(error (setq pos t
mismatch t)))
;; If found a "matching" paren, see if it is the right
;; kind of paren to match the one we started at.
(if (integerp pos)
(let ((beg (min pos oldpos)) (end (max pos oldpos)))
(and (/= (char-syntax (char-after beg)) ?\$)
(setq mismatch
(not (eq (char-after (1- end))
;; This can give nil.
(matching-paren (char-after beg))))))))
;; 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)
(progn
(add-to-list 'facemenu-unlisted-faces
'paren-mismatch)
(make-face 'paren-mismatch)
(or (face-nontrivial-p 'paren-mismatch t)
(progn
(set-face-background 'paren-mismatch
"purple")
(set-face-foreground 'paren-mismatch
"white")))
(setq show-paren-mismatch-face 'paren-mismatch)))
(if show-paren-mismatch-face
(setq face show-paren-mismatch-face)
(message "Paren mismatch"))))
)))
(cond (pos
(if (or (= dir -1)
(not (integerp pos)))
;; 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.
(let ((from (if (= dir 1)
(point)
(1- (point))))
(to (if (= dir 1)
(1+ (point))
(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 '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 found.
;; If it's an unmatched paren, turn off any such highlighting.
(or (and (not (integerp pos))
(delete-overlay show-paren-overlay))
(if show-paren-overlay
(move-overlay show-paren-overlay (- pos dir) pos
(current-buffer))
(setq show-paren-overlay
(make-overlay (- pos dir) pos))))
;; Always set the overlay face, since it varies.
(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))
(and show-paren-overlay-1 (overlay-buffer show-paren-overlay-1)
(delete-overlay show-paren-overlay-1)))))))
;;; For back compatibility we turn ourselves on if we're dumped or loaded.
(add-hook 'window-setup-hook '(lambda () (show-paren-mode t)))
(show-paren-mode t)
(provide 'paren)
;;; paren.el ends here
|
