1 ;;; paren.el --- highlight matching paren.
2 ;; Copyright (C) 1993 Free Software Foundation, Inc.
4 ;; Author: rms@gnu.ai.mit.edu
6 ;; Keywords: languages, faces
8 ;; This file is part of GNU Emacs.
10 ;; GNU Emacs is free software; you can redistribute it and/or modify
11 ;; it under the terms of the GNU General Public License as published by
12 ;; the Free Software Foundation; either version 2, or (at your option)
15 ;; GNU Emacs is distributed in the hope that it will be useful,
16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 ;; GNU General Public License for more details.
20 ;; You should have received a copy of the GNU General Public License
21 ;; along with GNU Emacs; see the file COPYING. If not, write to
22 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
26 ;; Load this and it will display highlighting on whatever
27 ;; paren matches the one before or after point.
31 ;; This is the overlay used to highlight the matching paren.
32 (defvar show-paren-overlay nil
)
33 ;; This is the overlay used to highlight the closeparen
34 ;; right before point.
35 (defvar show-paren-overlay-1 nil
)
37 (defvar show-paren-mismatch-face nil
)
39 (defvar show-paren-face
'region
40 "*Name of face to use for showing the matching paren.")
42 ;; Find the place to show, if there is one,
43 ;; and show it until input arrives.
44 (defun show-paren-command-hook ()
45 ;; Do nothing if no window system to display results with.
46 ;; Do nothing if input is pending.
47 (if (and window-system
(sit-for 0))
48 (let (pos dir mismatch
(oldpos (point))
49 (face show-paren-face
))
50 (cond ((eq (char-syntax (following-char)) ?\
()
52 ((eq (char-syntax (preceding-char)) ?\
))
57 ;; Determine the range within which to look for a match.
58 (if blink-matching-paren-distance
59 (narrow-to-region (max (point-min)
60 (- (point) blink-matching-paren-distance
))
62 (+ (point) blink-matching-paren-distance
))))
63 ;; Scan across one sexp within that range.
65 (setq pos
(scan-sexps (point) dir
))
67 ;; See if the "matching" paren is the right kind of paren
68 ;; to match the one we started at.
70 (let ((beg (min pos oldpos
)) (end (max pos oldpos
)))
71 (and (/= (char-syntax (char-after beg
)) ?\$
)
73 (/= (char-after (1- end
))
74 (logand (lsh (aref (syntax-table)
78 ;; If they don't properly match, use a different face,
79 ;; or print a message.
82 (and (null show-paren-mismatch-face
)
84 (or (setq show-paren-mismatch-face
85 (internal-find-face 'paren-mismatch
))
87 (make-face 'paren-mismatch
)
88 (setq show-paren-mismatch-face
90 (set-face-background 'paren-mismatch
92 (if show-paren-mismatch-face
93 (setq face show-paren-mismatch-face
)
94 (message "Paren mismatch"))))
98 ;; If matching backwards, highlight the closeparen
99 ;; before point as well as its matching open.
101 (if show-paren-overlay-1
102 (move-overlay show-paren-overlay-1
103 (+ (point) dir
) (point)
105 (setq show-paren-overlay-1
106 (make-overlay (- pos dir
) pos
)))
107 (overlay-put show-paren-overlay-1
'face face
))
108 ;; Otherwise, turn off any such highlighting.
109 (and show-paren-overlay-1
110 (overlay-buffer show-paren-overlay-1
)
111 (delete-overlay show-paren-overlay-1
)))
112 ;; Turn on highlighting for the matching paren.
113 (if show-paren-overlay
114 (move-overlay show-paren-overlay
(- pos dir
) pos
116 (setq show-paren-overlay
117 (make-overlay (- pos dir
) pos
)))
118 (overlay-put show-paren-overlay
'face face
))
120 ;; If not at a paren that has a match,
121 ;; turn off any previous paren highlighting.
122 (and show-paren-overlay
(overlay-buffer show-paren-overlay
)
123 (delete-overlay show-paren-overlay
))
124 (and show-paren-overlay-1
(overlay-buffer show-paren-overlay-1
)
125 (delete-overlay show-paren-overlay-1
)))))))
129 (setq blink-paren-function nil
)
130 (add-hook 'post-command-hook
'show-paren-command-hook
)))
131 ;;; This is in case paren.el is preloaded.
132 (add-hook 'window-setup-hook
136 (setq blink-paren-function nil
)
137 (add-hook 'post-command-hook
138 'show-paren-command-hook
))))))
141 ;;; paren.el ends here