| 1 | ;;; paren.el --- highlight matching paren. |
| 2 | |
| 3 | ;; Copyright (C) 1993, 1996 Free Software Foundation, Inc. |
| 4 | |
| 5 | ;; Author: rms@gnu.ai.mit.edu |
| 6 | ;; Maintainer: FSF |
| 7 | ;; Keywords: languages, faces |
| 8 | |
| 9 | ;; This file is part of GNU Emacs. |
| 10 | |
| 11 | ;; GNU Emacs is free software; you can redistribute it and/or modify |
| 12 | ;; it under the terms of the GNU General Public License as published by |
| 13 | ;; the Free Software Foundation; either version 2, or (at your option) |
| 14 | ;; any later version. |
| 15 | |
| 16 | ;; GNU Emacs is distributed in the hope that it will be useful, |
| 17 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 18 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 19 | ;; GNU General Public License for more details. |
| 20 | |
| 21 | ;; You should have received a copy of the GNU General Public License |
| 22 | ;; along with GNU Emacs; see the file COPYING. If not, write to the |
| 23 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| 24 | ;; Boston, MA 02111-1307, USA. |
| 25 | |
| 26 | ;;; Commentary: |
| 27 | |
| 28 | ;; Load this and it will display highlighting on whatever |
| 29 | ;; paren matches the one before or after point. |
| 30 | |
| 31 | ;;; Code: |
| 32 | |
| 33 | ;; This is the overlay used to highlight the matching paren. |
| 34 | (defvar show-paren-overlay nil) |
| 35 | ;; This is the overlay used to highlight the closeparen right before point. |
| 36 | (defvar show-paren-overlay-1 nil) |
| 37 | |
| 38 | (defvar show-paren-mode nil) |
| 39 | (defvar show-paren-idle-timer nil) |
| 40 | |
| 41 | (defvar show-paren-mismatch-face nil) |
| 42 | |
| 43 | (defvar show-paren-delay (if (featurep 'lisp-float-type) 0.125 1) |
| 44 | "*Time in seconds to delay before showing the matching paren.") |
| 45 | |
| 46 | (defvar show-paren-face 'region |
| 47 | "*Name of the face to use for showing the matching paren.") |
| 48 | |
| 49 | ;;;###autoload |
| 50 | (defun show-paren-mode (&optional arg) |
| 51 | "Toggle Show Paren mode. |
| 52 | With prefix ARG, turn Show Paren mode on if and only if ARG is positive. |
| 53 | Returns the new status of Show Paren mode (non-nil means on). |
| 54 | |
| 55 | When Show Paren mode is enabled, any matching parenthesis is highlighted |
| 56 | after `show-paren-delay' seconds of Emacs idle time." |
| 57 | (interactive "P") |
| 58 | (if window-system |
| 59 | (let ((on-p (if arg |
| 60 | (> (prefix-numeric-value arg) 0) |
| 61 | (not show-paren-mode)))) |
| 62 | (setq blink-matching-paren-on-screen (not on-p)) |
| 63 | (and show-paren-idle-timer (cancel-timer show-paren-idle-timer)) |
| 64 | (if on-p |
| 65 | (setq show-paren-idle-timer (run-with-idle-timer show-paren-delay t |
| 66 | 'show-paren-function)) |
| 67 | (and show-paren-overlay (overlay-buffer show-paren-overlay) |
| 68 | (delete-overlay show-paren-overlay)) |
| 69 | (and show-paren-overlay-1 (overlay-buffer show-paren-overlay-1) |
| 70 | (delete-overlay show-paren-overlay-1))) |
| 71 | (setq show-paren-mode on-p)))) |
| 72 | |
| 73 | ;; Find the place to show, if there is one, |
| 74 | ;; and show it until input arrives. |
| 75 | (defun show-paren-function () |
| 76 | ;; Do nothing if no window system to display results with. |
| 77 | ;; Do nothing if executing keyboard macro. |
| 78 | ;; Do nothing if input is pending. |
| 79 | (if window-system |
| 80 | (let (pos dir mismatch (oldpos (point)) |
| 81 | (face show-paren-face)) |
| 82 | (cond ((eq (char-syntax (preceding-char)) ?\)) |
| 83 | (setq dir -1)) |
| 84 | ((eq (char-syntax (following-char)) ?\() |
| 85 | (setq dir 1))) |
| 86 | (if dir |
| 87 | (save-excursion |
| 88 | (save-restriction |
| 89 | ;; Determine the range within which to look for a match. |
| 90 | (if blink-matching-paren-distance |
| 91 | (narrow-to-region (max (point-min) |
| 92 | (- (point) blink-matching-paren-distance)) |
| 93 | (min (point-max) |
| 94 | (+ (point) blink-matching-paren-distance)))) |
| 95 | ;; Scan across one sexp within that range. |
| 96 | (condition-case () |
| 97 | (setq pos (scan-sexps (point) dir)) |
| 98 | (error nil)) |
| 99 | ;; See if the "matching" paren is the right kind of paren |
| 100 | ;; to match the one we started at. |
| 101 | (if pos |
| 102 | (let ((beg (min pos oldpos)) (end (max pos oldpos))) |
| 103 | (and (/= (char-syntax (char-after beg)) ?\$) |
| 104 | (setq mismatch |
| 105 | (not (eq (char-after (1- end)) |
| 106 | ;; This can give nil. |
| 107 | (matching-paren (char-after beg)))))))) |
| 108 | ;; If they don't properly match, use a different face, |
| 109 | ;; or print a message. |
| 110 | (if mismatch |
| 111 | (progn |
| 112 | (and (null show-paren-mismatch-face) |
| 113 | (x-display-color-p) |
| 114 | (progn |
| 115 | (add-to-list 'facemenu-unlisted-faces |
| 116 | 'paren-mismatch) |
| 117 | (make-face 'paren-mismatch) |
| 118 | (or (face-nontrivial-p 'paren-mismatch t) |
| 119 | (progn |
| 120 | (set-face-background 'paren-mismatch |
| 121 | "purple") |
| 122 | (set-face-foreground 'paren-mismatch |
| 123 | "white"))) |
| 124 | (setq show-paren-mismatch-face 'paren-mismatch))) |
| 125 | (if show-paren-mismatch-face |
| 126 | (setq face show-paren-mismatch-face) |
| 127 | (message "Paren mismatch")))) |
| 128 | ))) |
| 129 | (cond (pos |
| 130 | (if (= dir -1) |
| 131 | ;; If matching backwards, highlight the closeparen |
| 132 | ;; before point as well as its matching open. |
| 133 | (progn |
| 134 | (if show-paren-overlay-1 |
| 135 | (move-overlay show-paren-overlay-1 |
| 136 | (+ (point) dir) (point) |
| 137 | (current-buffer)) |
| 138 | (setq show-paren-overlay-1 |
| 139 | (make-overlay (+ (point) dir) (point)))) |
| 140 | ;; Always set the overlay face, since it varies. |
| 141 | (overlay-put show-paren-overlay-1 'face face)) |
| 142 | ;; Otherwise, turn off any such highlighting. |
| 143 | (and show-paren-overlay-1 |
| 144 | (overlay-buffer show-paren-overlay-1) |
| 145 | (delete-overlay show-paren-overlay-1))) |
| 146 | ;; Turn on highlighting for the matching paren. |
| 147 | (if show-paren-overlay |
| 148 | (move-overlay show-paren-overlay (- pos dir) pos |
| 149 | (current-buffer)) |
| 150 | (setq show-paren-overlay |
| 151 | (make-overlay (- pos dir) pos))) |
| 152 | ;; Always set the overlay face, since it varies. |
| 153 | (overlay-put show-paren-overlay 'face face)) |
| 154 | (t |
| 155 | ;; If not at a paren that has a match, |
| 156 | ;; turn off any previous paren highlighting. |
| 157 | (and show-paren-overlay (overlay-buffer show-paren-overlay) |
| 158 | (delete-overlay show-paren-overlay)) |
| 159 | (and show-paren-overlay-1 (overlay-buffer show-paren-overlay-1) |
| 160 | (delete-overlay show-paren-overlay-1))))))) |
| 161 | |
| 162 | ;;; For back compatibility we turn ourselves on if we're dumped or loaded. |
| 163 | (add-hook 'window-setup-hook '(lambda () (show-paren-mode t))) |
| 164 | (show-paren-mode t) |
| 165 | |
| 166 | (provide 'paren) |
| 167 | |
| 168 | ;;; paren.el ends here |