EIEIO&cl-generic: Add obsolescence warnings and fix corner case
[emacs.git] / lisp / reveal.el
blobb71df964aec8b375aefbc3ee601f3f0941dfb5d8
1 ;;; reveal.el --- Automatically reveal hidden text at point -*- lexical-binding: t -*-
3 ;; Copyright (C) 2000-2015 Free Software Foundation, Inc.
5 ;; Author: Stefan Monnier <monnier@iro.umontreal.ca>
6 ;; Keywords: outlines
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 3 of the License, or
13 ;; (at your option) any later version.
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. If not, see <http://www.gnu.org/licenses/>.
23 ;;; Commentary:
25 ;; Reveal mode is a minor mode that makes sure that text around point
26 ;; is always visible. When point enters a region of hidden text,
27 ;; `reveal-mode' temporarily makes it visible.
29 ;; This is normally used in conjunction with `outline-minor-mode',
30 ;; `hs-minor-mode', `hide-ifdef-mode', ...
32 ;; It only works with packages that hide text using overlays.
33 ;; Packages can provide special support for it by placing
34 ;; a function in the `reveal-toggle-invisible' property on the symbol
35 ;; used as the value of the `invisible' overlay property.
36 ;; The function is called right after revealing (or re-hiding) the
37 ;; text with two arguments: the overlay and a boolean that's non-nil
38 ;; if we have just revealed the text. When revealing, that function
39 ;; may re-hide some of the text.
41 ;;; Todo:
43 ;; - find other hysteresis features.
44 ;; - don't hide after a scroll command
45 ;; - delay hiding by a couple seconds (i.e. hide in the background)
47 ;;; Code:
49 (defgroup reveal nil
50 "Reveal hidden text on the fly."
51 :group 'convenience)
53 (defcustom reveal-around-mark t
54 "Reveal text around the mark, if active."
55 :type 'boolean
56 :group 'reveal)
58 (defvar reveal-open-spots nil
59 "List of spots in the buffer which are open.
60 Each element has the form (WINDOW . OVERLAY).")
61 (make-variable-buffer-local 'reveal-open-spots)
63 (defvar reveal-last-tick nil)
64 (make-variable-buffer-local 'reveal-last-tick)
66 ;; Actual code
68 (defun reveal-post-command ()
69 ;; Refresh the spots that might have changed.
70 ;; `Refreshing' here means to try and re-hide the corresponding text.
71 ;; We don't refresh everything correctly:
72 ;; - we only refresh spots in the current window.
73 ;; FIXME: do we actually know that (current-buffer) = (window-buffer) ?
74 (with-local-quit
75 (with-demoted-errors "Reveal: %s"
76 (let ((old-ols
77 (delq nil
78 (mapcar
79 (lambda (x)
80 ;; We refresh any spot in the current window as well
81 ;; as any spots associated with a dead window or
82 ;; a window which does not show this buffer any more.
83 (cond
84 ((eq (car x) (selected-window)) (cdr x))
85 ((not (and (window-live-p (car x))
86 (eq (window-buffer (car x))
87 (current-buffer))))
88 ;; Adopt this since it's owned by a window that's
89 ;; either not live or at least not showing this
90 ;; buffer any more.
91 (setcar x (selected-window))
92 (cdr x))))
93 reveal-open-spots))))
94 (setq old-ols (reveal-open-new-overlays old-ols))
95 (reveal-close-old-overlays old-ols)))))
97 (defun reveal-open-new-overlays (old-ols)
98 (let ((repeat t))
99 (while repeat
100 (setq repeat nil)
101 (dolist (ol (nconc (when (and reveal-around-mark mark-active)
102 (overlays-at (mark)))
103 (overlays-at (point))))
104 (setq old-ols (delq ol old-ols))
105 (when (overlay-start ol) ;Check it's still live.
106 (let ((inv (overlay-get ol 'invisible)) open)
107 (when (and inv
108 ;; There's an `invisible' property. Make sure it's
109 ;; actually invisible, and ellipsized.
110 (and (consp buffer-invisibility-spec)
111 (cdr (assq inv buffer-invisibility-spec)))
112 (or (setq open
113 (or (overlay-get ol 'reveal-toggle-invisible)
114 (and (symbolp inv)
115 (get inv 'reveal-toggle-invisible))
116 (overlay-get ol 'isearch-open-invisible-temporary)))
117 (overlay-get ol 'isearch-open-invisible)
118 (and (consp buffer-invisibility-spec)
119 (cdr (assq inv buffer-invisibility-spec))))
120 (overlay-put ol 'reveal-invisible inv))
121 (push (cons (selected-window) ol) reveal-open-spots)
122 (if (null open)
123 (overlay-put ol 'invisible nil)
124 ;; Use the provided opening function and repeat (since the
125 ;; opening function might have hidden a subpart around point
126 ;; or moved/killed some of the overlays).
127 (setq repeat t)
128 (condition-case err
129 (funcall open ol nil)
130 (error (message "!!Reveal-show (funcall %s %s nil): %s !!"
131 open ol err)
132 ;; Let's default to a meaningful behavior to avoid
133 ;; getting stuck in an infinite loop.
134 (setq repeat nil)
135 (overlay-put ol 'invisible nil))))))))))
136 old-ols)
138 (defun reveal-close-old-overlays (old-ols)
139 (if (or track-mouse ;Don't close in the middle of a click.
140 (not (eq reveal-last-tick
141 (setq reveal-last-tick (buffer-modified-tick)))))
142 ;; The buffer was modified since last command: let's refrain from
143 ;; closing any overlay because it tends to behave poorly when
144 ;; inserting text at the end of an overlay (basically the overlay
145 ;; should be rear-advance when it's open, but things like
146 ;; outline-minor-mode make it non-rear-advance because it's
147 ;; a better choice when it's closed).
149 ;; The last command was only a point motion or some such
150 ;; non-buffer-modifying command. Let's close whatever can be closed.
151 (dolist (ol old-ols)
152 (if (and (overlay-start ol) ;Check it's still live.
153 (>= (point) (save-excursion
154 (goto-char (overlay-start ol))
155 (line-beginning-position 1)))
156 (<= (point) (save-excursion
157 (goto-char (overlay-end ol))
158 (line-beginning-position 2)))
159 ;; If the application has moved the overlay to some other
160 ;; buffer, we'd better reset the buffer to its
161 ;; original state.
162 (eq (current-buffer) (overlay-buffer ol)))
163 ;; Still near the overlay: keep it open.
165 ;; Really close it.
166 (let* ((inv (overlay-get ol 'reveal-invisible))
167 (open (or (overlay-get ol 'reveal-toggle-invisible)
168 (get inv 'reveal-toggle-invisible)
169 (overlay-get ol 'isearch-open-invisible-temporary))))
170 (if (and (overlay-start ol) ;Check it's still live.
171 open)
172 (condition-case err
173 (funcall open ol t)
174 (error (message "!!Reveal-hide (funcall %s %s t): %s !!"
175 open ol err)))
176 (overlay-put ol 'invisible inv))
177 ;; Remove the overlay from the list of open spots.
178 (overlay-put ol 'reveal-invisible nil)
179 (setq reveal-open-spots
180 (delq (rassoc ol reveal-open-spots)
181 reveal-open-spots)))))))
183 (defvar reveal-mode-map
184 (let ((map (make-sparse-keymap)))
185 ;; Override the default move-beginning-of-line and move-end-of-line
186 ;; which skips valuable invisible text.
187 (define-key map [remap move-beginning-of-line] 'beginning-of-line)
188 (define-key map [remap move-end-of-line] 'end-of-line)
189 map))
191 ;;;###autoload
192 (define-minor-mode reveal-mode
193 "Toggle uncloaking of invisible text near point (Reveal mode).
194 With a prefix argument ARG, enable Reveal mode if ARG is
195 positive, and disable it otherwise. If called from Lisp, enable
196 Reveal mode if ARG is omitted or nil.
198 Reveal mode is a buffer-local minor mode. When enabled, it
199 reveals invisible text around point."
200 :group 'reveal
201 :lighter (global-reveal-mode nil " Reveal")
202 :keymap reveal-mode-map
203 (if reveal-mode
204 (progn
205 (set (make-local-variable 'search-invisible) t)
206 (add-hook 'post-command-hook 'reveal-post-command nil t))
207 (kill-local-variable 'search-invisible)
208 (remove-hook 'post-command-hook 'reveal-post-command t)))
210 ;;;###autoload
211 (define-minor-mode global-reveal-mode
212 "Toggle Reveal mode in all buffers (Global Reveal mode).
213 Reveal mode renders invisible text around point visible again.
215 With a prefix argument ARG, enable Global Reveal mode if ARG is
216 positive, and disable it otherwise. If called from Lisp, enable
217 the mode if ARG is omitted or nil."
218 :global t :group 'reveal
219 (setq-default reveal-mode global-reveal-mode)
220 (if global-reveal-mode
221 (progn
222 (setq search-invisible t)
223 (add-hook 'post-command-hook 'reveal-post-command))
224 (setq search-invisible 'open) ;FIXME
225 (remove-hook 'post-command-hook 'reveal-post-command)))
227 (provide 'reveal)
229 ;;; reveal.el ends here