1 ;;; reveal.el --- Automatically reveal hidden text at point
3 ;; Copyright (C) 2000, 2001, 2004, 2005 Free Software Foundation, Inc.
5 ;; Author: Stefan Monnier <monnier@cs.yale.edu>
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, Inc., 59 Temple Place - Suite 330,
23 ;; Boston, MA 02111-1307, USA.
27 ;; Reveal mode is a minor mode that makes sure that text around point
28 ;; is always visible. When point enters a region of hidden text,
29 ;; `reveal-mode' temporarily makes it visible.
31 ;; This is normally used in conjunction with `outline-minor-mode',
32 ;; `hs-minor-mode', `hide-ifdef-mode', ...
34 ;; It only works with packages that hide text using overlays.
35 ;; Packages can provide special support for it by placing
36 ;; a function in the `reveal-toggle-invisible' property on the symbol
37 ;; used as the value of the `invisible' overlay property.
38 ;; The function is called right after revealing (or re-hiding) the
39 ;; text with two arguments: the overlay and a boolean that's non-nil
40 ;; if we have just revealed the text. When revealing, that function
41 ;; may re-hide some of the text.
45 ;; - find other hysteresis features.
52 "Reveal hidden text on the fly."
55 (defcustom reveal-around-mark t
56 "Reveal text around the mark, if active."
59 (defvar reveal-open-spots nil)
60 (make-variable-buffer-local 'reveal-open-spots)
62 (defvar reveal-last-tick nil)
63 (make-variable-buffer-local 'reveal-last-tick)
67 (defun reveal-post-command ()
68 ;; Refresh the spots that might have changed.
69 ;; `Refreshing' here means to try and re-hide the corresponding text.
70 ;; We don't refresh everything correctly:
71 ;; - we only refresh spots in the current window.
72 ;; FIXME: do we actually know that (current-buffer) = (window-buffer) ?
75 (let* ((spots (cvs-partition
77 ;; We refresh any spot in the current window as well
78 ;; as any spots associated with a dead window or a window
79 ;; which does not show this buffer any more.
80 (or (eq (car x) (selected-window))
81 (not (window-live-p (car x)))
82 (not (eq (window-buffer (car x))
85 (old-ols (mapcar 'cdr (car spots)))
87 (setq reveal-open-spots (cdr spots))
91 (dolist (ol (nconc (when (and reveal-around-mark mark-active)
93 (overlays-at (point))))
94 (push (cons (selected-window) ol) reveal-open-spots)
95 (setq old-ols (delq ol old-ols))
96 (let ((inv (overlay-get ol 'invisible)) open)
98 ;; There's an `invisible' property. Make sure it's
99 ;; actually invisible.
100 (or (not (listp buffer-invisibility-spec))
101 (memq inv buffer-invisibility-spec)
102 (assq inv buffer-invisibility-spec))
104 (or (overlay-get ol 'reveal-toggle-invisible)
106 (get inv 'reveal-toggle-invisible))
107 (overlay-get ol 'isearch-open-invisible-temporary)))
108 (overlay-get ol 'isearch-open-invisible)
109 (and (consp buffer-invisibility-spec)
110 (cdr (assq inv buffer-invisibility-spec))))
111 (overlay-put ol 'reveal-invisible inv))
113 (overlay-put ol 'invisible nil)
114 ;; Use the provided opening function and repeat (since the
115 ;; opening function might have hidden a subpart around point).
118 (funcall open ol nil)
119 (error (message "!!Reveal-show (funcall %s %s nil): %s !!"
121 ;; Let's default to a meaningful behavior to avoid
122 ;; getting stuck in an infinite loop.
124 (overlay-put ol 'invisible nil))))))))
125 ;; Close old overlays.
126 (if (not (eq reveal-last-tick
127 (setq reveal-last-tick (buffer-modified-tick))))
128 ;; The buffer was modified since last command: let's refrain from
129 ;; closing any overlay because it tends to behave poorly when
130 ;; inserting text at the end of an overlay (basically the overlay
131 ;; should be rear-advance when it's open, but things like
132 ;; outline-minor-mode make it non-rear-advance because it's
133 ;; a better choice when it's closed).
135 (push (cons (selected-window) ol) reveal-open-spots))
136 ;; The last command was only a point motion or some such
137 ;; non-buffer-modifying command. Let's close whatever can be closed.
139 (when (and (eq (current-buffer) (overlay-buffer ol))
140 (not (rassq ol reveal-open-spots)))
141 (if (and (>= (point) (save-excursion
142 (goto-char (overlay-start ol))
143 (line-beginning-position 1)))
144 (<= (point) (save-excursion
145 (goto-char (overlay-end ol))
146 (line-beginning-position 2))))
147 ;; Still near the overlay: keep it open.
148 (push (cons (selected-window) ol) reveal-open-spots)
150 (let ((open (overlay-get ol 'reveal-toggle-invisible)) inv)
152 (and (setq inv (overlay-get ol 'reveal-invisible))
153 (setq open (or (get inv 'reveal-toggle-invisible)
154 (overlay-get ol 'isearch-open-invisible-temporary)))))
157 (error (message "!!Reveal-hide (funcall %s %s t): %s !!"
159 (overlay-put ol 'invisible inv))))))))
160 (error (message "Reveal: %s" err)))))
162 (defvar reveal-mode-map
163 (let ((map (make-sparse-keymap)))
164 ;; Override the default move-beginning-of-line and move-end-of-line
165 ;; which skips valuable invisible text.
166 (define-key map [remap move-beginning-of-line] 'beginning-of-line)
167 (define-key map [remap move-end-of-line] 'end-of-line)
171 (define-minor-mode reveal-mode
172 "Toggle Reveal mode on or off.
173 Reveal mode renders invisible text around point visible again.
175 Interactively, with no prefix argument, toggle the mode.
176 With universal prefix ARG (or if ARG is nil) turn mode on.
177 With zero or negative ARG turn mode off."
179 :lighter (global-reveal-mode nil " Reveal")
180 :keymap reveal-mode-map
183 (set (make-local-variable 'search-invisible) t)
184 (add-hook 'post-command-hook 'reveal-post-command nil t))
185 (kill-local-variable 'search-invisible)
186 (remove-hook 'post-command-hook 'reveal-post-command t)))
189 (define-minor-mode global-reveal-mode
190 "Toggle Reveal mode in all buffers on or off.
191 Reveal mode renders invisible text around point visible again.
193 Interactively, with no prefix argument, toggle the mode.
194 With universal prefix ARG (or if ARG is nil) turn mode on.
195 With zero or negative ARG turn mode off."
196 :global t :group 'reveal
197 (setq-default reveal-mode global-reveal-mode)
198 (if global-reveal-mode
200 (setq search-invisible t)
201 (add-hook 'post-command-hook 'reveal-post-command))
202 (setq search-invisible 'open) ;FIXME
203 (remove-hook 'post-command-hook 'reveal-post-command)))
207 ;; arch-tag: 96ba0242-2274-4ed7-8e10-26bc0707b4d8
208 ;;; reveal.el ends here