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8e2b057d | 1 | ;;; button.el --- clickable buttons |
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2 | ;; |
3 | ;; Copyright (C) 2001 Free Software Foundation, Inc. | |
4 | ;; | |
5 | ;; Author: Miles Bader <miles@gnu.org> | |
6 | ;; Keywords: extensions | |
7 | ;; | |
8 | ;; This file is part of GNU Emacs. | |
9 | ;; | |
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) | |
13 | ;; any later version. | |
14 | ;; | |
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. | |
19 | ;; | |
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 the | |
22 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
23 | ;; Boston, MA 02111-1307, USA. | |
24 | ||
25 | ;;; Commentary: | |
26 | ;; | |
27 | ;; This package defines functions for inserting and manipulating | |
28 | ;; clickable buttons in Emacs buffers, such as might be used for help | |
29 | ;; hyperlinks, etc. | |
30 | ;; | |
31 | ;; In some ways it duplicates functionality also offered by the | |
32 | ;; `widget' package, but the button package has the advantage that it | |
33 | ;; is (1) much faster, (2) much smaller, and (3) much, much, simpler | |
34 | ;; (the code, that is, not the interface). | |
35 | ;; | |
36 | ;; Buttons can either use overlays, in which case the button is | |
37 | ;; represented by the overlay itself, or text-properties, in which case | |
38 | ;; the button is represented by a marker or buffer-position pointing | |
39 | ;; somewhere in the button. In the latter case, no markers into the | |
40 | ;; buffer are retained, which is important for speed if there are are | |
41 | ;; extremely large numbers of buttons. | |
42 | ;; | |
43 | ;; Using `define-button-type' to define default properties for buttons | |
44 | ;; is not necessary, but it is is encouraged, since doing so makes the | |
45 | ;; resulting code clearer and more efficient. | |
46 | ;; | |
47 | ||
48 | ;;; Code: | |
49 | ||
50 | \f | |
51 | ;; Globals | |
52 | ||
f2e24189 EZ |
53 | (defface button '((((type pc) (class color)) |
54 | (:foreground "lightblue")) | |
55 | (t :underline t)) | |
d28242e1 MR |
56 | "Default face used for buttons." |
57 | :group 'faces) | |
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58 | |
59 | ;;;###autoload | |
60 | (defvar button-map | |
61 | (let ((map (make-sparse-keymap))) | |
62 | (define-key map "\r" 'push-button) | |
63 | (define-key map [mouse-2] 'push-button) | |
64 | map) | |
65 | "Keymap used by buttons.") | |
66 | ||
67 | ;;;###autoload | |
68 | (defvar button-buffer-map | |
69 | (let ((map (make-sparse-keymap))) | |
70 | (define-key map [?\t] 'forward-button) | |
71 | (define-key map [backtab] 'backward-button) | |
72 | map) | |
73 | "Keymap useful for buffers containing buttons. | |
74 | Mode-specific keymaps may want to use this as their parent keymap.") | |
75 | ||
76 | ;; Default properties for buttons | |
77 | (put 'default-button 'face 'button) | |
78 | (put 'default-button 'mouse-face 'highlight) | |
79 | (put 'default-button 'keymap button-map) | |
80 | (put 'default-button 'type 'button) | |
62dc75c4 | 81 | (put 'default-button 'action 'ignore) |
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82 | (put 'default-button 'help-echo "mouse-2, RET: Push this button") |
83 | ;; Make overlay buttons go away if their underlying text is deleted. | |
84 | (put 'default-button 'evaporate t) | |
85 | ;; Prevent insertions adjacent to the text-property buttons from | |
86 | ;; inheriting its properties. | |
87 | (put 'default-button 'rear-nonsticky t) | |
88 | ;; Text property buttons don't have a `button' property of their own, so | |
89 | ;; they inherit this. | |
90 | (put 'default-button 'button t) | |
91 | ||
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92 | ;; A `category-symbol' property for the default button type |
93 | (put 'button 'button-category-symbol 'default-button) | |
94 | ||
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95 | \f |
96 | ;; Button types (which can be used to hold default properties for buttons) | |
97 | ||
ded42dd3 MB |
98 | ;; Because button-type properties are inherited by buttons using the |
99 | ;; special `category' property (implemented by both overlays and | |
100 | ;; text-properties), we need to store them on a symbol to which the | |
101 | ;; `category' properties can point. Instead of using the symbol that's | |
102 | ;; the name of each button-type, however, we use a separate symbol (with | |
103 | ;; `-button' appended, and uninterned) to store the properties. This is | |
104 | ;; to avoid name clashes. | |
105 | ||
106 | ;; [this is an internal function] | |
107 | (defsubst button-category-symbol (type) | |
108 | "Return the symbol used by button-type TYPE to store properties. | |
109 | Buttons inherit them by setting their `category' property to that symbol." | |
110 | (or (get type 'button-category-symbol) | |
111 | (error "Unknown button type `%s'" type))) | |
112 | ||
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113 | ;;;###autoload |
114 | (defun define-button-type (name &rest properties) | |
115 | "Define a `button type' called NAME. | |
116 | The remaining arguments form a sequence of PROPERTY VALUE pairs, | |
117 | specifying properties to use as defaults for buttons with this type | |
118 | \(a button's type may be set by giving it a `type' property when | |
ecdbe16a | 119 | creating the button, using the :type keyword argument). |
ded42dd3 | 120 | |
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121 | In addition, the keyword argument :supertype may be used to specify a |
122 | button-type from which NAME inherits its default property values | |
123 | \(however, the inheritance happens only when NAME is defined; subsequent | |
124 | changes to a supertype are not reflected in its subtypes)." | |
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125 | (let ((catsym (make-symbol (concat (symbol-name name) "-button"))) |
126 | (super-catsym | |
127 | (button-category-symbol | |
530893b2 | 128 | (or (plist-get properties 'supertype) |
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129 | (plist-get properties :supertype) |
130 | 'button)))) | |
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131 | ;; Provide a link so that it's easy to find the real symbol. |
132 | (put name 'button-category-symbol catsym) | |
133 | ;; Initialize NAME's properties using the global defaults. | |
ded42dd3 | 134 | (let ((default-props (symbol-plist super-catsym))) |
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135 | (while default-props |
136 | (put catsym (pop default-props) (pop default-props)))) | |
137 | ;; Add NAME as the `type' property, which will then be returned as | |
138 | ;; the type property of individual buttons. | |
139 | (put catsym 'type name) | |
140 | ;; Add the properties in PROPERTIES to the real symbol. | |
141 | (while properties | |
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142 | (let ((prop (pop properties))) |
143 | (when (eq prop :supertype) | |
144 | (setq prop 'supertype)) | |
145 | (put catsym prop (pop properties)))) | |
588c722f MB |
146 | ;; Make sure there's a `supertype' property |
147 | (unless (get catsym 'supertype) | |
148 | (put catsym 'supertype 'button)) | |
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149 | name)) |
150 | ||
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151 | (defun button-type-put (type prop val) |
152 | "Set the button-type TYPE's PROP property to VAL." | |
153 | (put (button-category-symbol type) prop val)) | |
154 | ||
155 | (defun button-type-get (type prop) | |
156 | "Get the property of button-type TYPE named PROP." | |
157 | (get (button-category-symbol type) prop)) | |
158 | ||
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159 | (defun button-type-subtype-p (type supertype) |
160 | "Return t if button-type TYPE is a subtype of SUPERTYPE." | |
161 | (or (eq type supertype) | |
162 | (and type | |
163 | (button-type-subtype-p (button-type-get type 'supertype) | |
164 | supertype)))) | |
165 | ||
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166 | \f |
167 | ;; Button properties and other attributes | |
168 | ||
169 | (defun button-start (button) | |
170 | "Return the position at which BUTTON starts." | |
171 | (if (overlayp button) | |
172 | (overlay-start button) | |
173 | ;; Must be a text-property button. | |
174 | (or (previous-single-property-change (1+ button) 'button) | |
175 | (point-min)))) | |
176 | ||
177 | (defun button-end (button) | |
178 | "Return the position at which BUTTON ends." | |
179 | (if (overlayp button) | |
180 | (overlay-end button) | |
181 | ;; Must be a text-property button. | |
182 | (or (next-single-property-change button 'button) | |
183 | (point-max)))) | |
184 | ||
185 | (defun button-get (button prop) | |
186 | "Get the property of button BUTTON named PROP." | |
187 | (if (overlayp button) | |
188 | (overlay-get button prop) | |
189 | ;; Must be a text-property button. | |
190 | (get-text-property button prop))) | |
191 | ||
192 | (defun button-put (button prop val) | |
193 | "Set BUTTON's PROP property to VAL." | |
194 | ;; Treat some properties specially. | |
530893b2 | 195 | (cond ((memq prop '(type :type)) |
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196 | ;; We translate a `type' property a `category' property, since |
197 | ;; that's what's actually used by overlays/text-properties for | |
198 | ;; inheriting properties. | |
199 | (setq prop 'category) | |
200 | (setq val (button-category-symbol val))) | |
201 | ((eq prop 'category) | |
202 | ;; Disallow updating the `category' property directly. | |
203 | (error "Button `category' property may not be set directly"))) | |
204 | ;; Add the property. | |
205 | (if (overlayp button) | |
206 | (overlay-put button prop val) | |
207 | ;; Must be a text-property button. | |
208 | (put-text-property | |
209 | (or (previous-single-property-change (1+ button) 'button) | |
210 | (point-min)) | |
211 | (or (next-single-property-change button 'button) | |
212 | (point-max)) | |
213 | prop val))) | |
214 | ||
1e00f720 | 215 | (defsubst button-activate (button &optional use-mouse-action) |
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216 | "Call BUTTON's action property. |
217 | If USE-MOUSE-ACTION is non-nil, invoke the button's mouse-action | |
218 | instead of its normal action; if the button has no mouse-action, | |
219 | the normal action is used instead." | |
220 | (funcall (or (and use-mouse-action (button-get button 'mouse-action)) | |
221 | (button-get button 'action)) | |
222 | button)) | |
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223 | |
224 | (defun button-label (button) | |
225 | "Return BUTTON's text label." | |
226 | (buffer-substring-no-properties (button-start button) (button-end button))) | |
227 | ||
530893b2 | 228 | (defsubst button-type (button) |
ecdbe16a | 229 | "Return BUTTON's button-type." |
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230 | (button-get button 'type)) |
231 | ||
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232 | (defun button-has-type-p (button type) |
233 | "Return t if BUTTON has button-type TYPE, or one of TYPE's subtypes." | |
234 | (button-type-subtype-p (button-get button 'type) type)) | |
235 | ||
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236 | \f |
237 | ;; Creating overlay buttons | |
238 | ||
239 | ;;;###autoload | |
240 | (defun make-button (beg end &rest properties) | |
241 | "Make a button from BEG to END in the current buffer. | |
242 | The remaining arguments form a sequence of PROPERTY VALUE pairs, | |
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243 | specifying properties to add to the button. |
244 | In addition, the keyword argument :type may be used to specify a | |
245 | button-type from which to inherit other properties; see | |
246 | `define-button-type'. | |
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247 | |
248 | Also see `make-text-button', `insert-button'." | |
249 | (let ((overlay (make-overlay beg end nil t nil))) | |
250 | (while properties | |
251 | (button-put overlay (pop properties) (pop properties))) | |
252 | ;; Put a pointer to the button in the overlay, so it's easy to get | |
253 | ;; when we don't actually have a reference to the overlay. | |
254 | (overlay-put overlay 'button overlay) | |
255 | ;; If the user didn't specify a type, use the default. | |
256 | (unless (overlay-get overlay 'category) | |
257 | (overlay-put overlay 'category 'default-button)) | |
258 | ;; OVERLAY is the button, so return it | |
259 | overlay)) | |
260 | ||
261 | ;;;###autoload | |
262 | (defun insert-button (label &rest properties) | |
263 | "Insert a button with the label LABEL. | |
264 | The remaining arguments form a sequence of PROPERTY VALUE pairs, | |
ecdbe16a MB |
265 | specifying properties to add to the button. |
266 | In addition, the keyword argument :type may be used to specify a | |
267 | button-type from which to inherit other properties; see | |
268 | `define-button-type'. | |
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269 | |
270 | Also see `insert-text-button', `make-button'." | |
271 | (apply #'make-button | |
272 | (prog1 (point) (insert label)) | |
273 | (point) | |
274 | properties)) | |
275 | ||
276 | \f | |
277 | ;; Creating text-property buttons | |
278 | ||
279 | ;;;###autoload | |
280 | (defun make-text-button (beg end &rest properties) | |
281 | "Make a button from BEG to END in the current buffer. | |
282 | The remaining arguments form a sequence of PROPERTY VALUE pairs, | |
ecdbe16a MB |
283 | specifying properties to add to the button. |
284 | In addition, the keyword argument :type may be used to specify a | |
285 | button-type from which to inherit other properties; see | |
286 | `define-button-type'. | |
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287 | |
288 | This function is like `make-button', except that the button is actually | |
289 | part of the text instead of being a property of the buffer. Creating | |
290 | large numbers of buttons can also be somewhat faster using | |
291 | `make-text-button'. | |
292 | ||
293 | Also see `insert-text-button'." | |
294 | (let (prop val) | |
295 | (while properties | |
296 | (setq prop (pop properties)) | |
297 | (setq val (pop properties)) | |
298 | ;; Note that all the following code is basically equivalent to | |
299 | ;; `button-put', but we can do it much more efficiently since we | |
300 | ;; already have BEG and END. | |
530893b2 | 301 | (cond ((memq prop '(type :type)) |
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302 | ;; We translate a `type' property into a `category' |
303 | ;; property, since that's what's actually used by | |
304 | ;; text-properties for inheritance. | |
305 | (setq prop 'category) | |
306 | (setq val (button-category-symbol val))) | |
307 | ((eq prop 'category) | |
308 | ;; Disallow setting the `category' property directly. | |
309 | (error "Button `category' property may not be set directly"))) | |
310 | ;; Add the property. | |
311 | (put-text-property beg end prop val))) | |
312 | ;; Return something that can be used to get at the button. | |
313 | beg) | |
314 | ||
315 | ;;;###autoload | |
316 | (defun insert-text-button (label &rest properties) | |
317 | "Insert a button with the label LABEL. | |
318 | The remaining arguments form a sequence of PROPERTY VALUE pairs, | |
ecdbe16a MB |
319 | specifying properties to add to the button. |
320 | In addition, the keyword argument :type may be used to specify a | |
321 | button-type from which to inherit other properties; see | |
322 | `define-button-type'. | |
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323 | |
324 | This function is like `insert-button', except that the button is | |
325 | actually part of the text instead of being a property of the buffer. | |
326 | Creating large numbers of buttons can also be somewhat faster using | |
327 | `insert-text-button'. | |
328 | ||
329 | Also see `make-text-button'." | |
330 | (apply #'make-text-button | |
331 | (prog1 (point) (insert label)) | |
332 | (point) | |
333 | properties)) | |
334 | ||
335 | \f | |
336 | ;; Finding buttons in a buffer | |
337 | ||
338 | (defun button-at (pos) | |
339 | "Return the button at position POS in the current buffer, or nil." | |
340 | (let ((button (get-char-property pos 'button))) | |
341 | (if (or (overlayp button) (null button)) | |
342 | button | |
343 | ;; Must be a text-property button; return a marker pointing to it. | |
344 | (copy-marker pos t)))) | |
345 | ||
fee34a28 MB |
346 | (defun next-button (pos &optional count-current) |
347 | "Return the next button after position POS in the current buffer. | |
0c26f463 | 348 | If COUNT-CURRENT is non-nil, count any button at POS in the search, |
fee34a28 | 349 | instead of starting at the next button." |
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350 | (unless count-current |
351 | ;; Search for the next button boundary. | |
352 | (setq pos (next-single-char-property-change pos 'button))) | |
fee34a28 MB |
353 | (and (< pos (point-max)) |
354 | (or (button-at pos) | |
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355 | ;; We must have originally been on a button, and are now in |
356 | ;; the inter-button space. Recurse to find a button. | |
fee34a28 | 357 | (next-button pos)))) |
0c26f463 | 358 | |
fee34a28 | 359 | (defun previous-button (pos &optional count-current) |
0c26f463 | 360 | "Return the Nth button before position POS in the current buffer. |
0c26f463 | 361 | If COUNT-CURRENT is non-nil, count any button at POS in the search, |
fee34a28 MB |
362 | instead of starting at the next button." |
363 | (unless count-current | |
364 | (setq pos (previous-single-char-property-change pos 'button))) | |
365 | (and (> pos (point-min)) | |
366 | (or (button-at (1- pos)) | |
367 | ;; We must have originally been on a button, and are now in | |
368 | ;; the inter-button space. Recurse to find a button. | |
369 | (previous-button pos)))) | |
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370 | |
371 | \f | |
372 | ;; User commands | |
373 | ||
d6bc0bdc | 374 | (defun push-button (&optional pos use-mouse-action) |
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375 | "Perform the action specified by a button at location POS. |
376 | POS may be either a buffer position or a mouse-event. | |
d6bc0bdc MB |
377 | If USE-MOUSE-ACTION is non-nil, invoke the button's mouse-action |
378 | instead of its normal action; if the button has no mouse-action, | |
379 | the normal action is used instead. | |
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380 | POS defaults to point, except when `push-button' is invoked |
381 | interactively as the result of a mouse-event, in which case, the | |
382 | mouse event is used. | |
383 | If there's no button at POS, do nothing and return nil, otherwise | |
384 | return t." | |
385 | (interactive | |
386 | (list (if (integerp last-command-event) (point) last-command-event))) | |
387 | (if (and (not (integerp pos)) (eventp pos)) | |
388 | ;; POS is a mouse event; switch to the proper window/buffer | |
389 | (let ((posn (event-start pos))) | |
390 | (with-current-buffer (window-buffer (posn-window posn)) | |
d6bc0bdc | 391 | (push-button (posn-point posn) t))) |
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392 | ;; POS is just normal position |
393 | (let ((button (button-at (or pos (point))))) | |
394 | (if (not button) | |
395 | nil | |
d6bc0bdc | 396 | (button-activate button use-mouse-action) |
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397 | t)))) |
398 | ||
399 | (defun forward-button (n &optional wrap display-message) | |
400 | "Move to the Nth next button, or Nth previous button if N is negative. | |
fee34a28 | 401 | If N is 0, move to the start of any button at point. |
0c26f463 MB |
402 | If WRAP is non-nil, moving past either end of the buffer continues from the |
403 | other end. | |
404 | If DISPLAY-MESSAGE is non-nil, the button's help-echo string is displayed. | |
fee34a28 | 405 | Any button with a non-nil `skip' property is skipped over. |
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406 | Returns the button found." |
407 | (interactive "p\nd\nd") | |
fee34a28 MB |
408 | (let (button) |
409 | (if (zerop n) | |
410 | ;; Move to start of current button | |
411 | (if (setq button (button-at (point))) | |
412 | (goto-char (button-start button))) | |
413 | ;; Move to Nth next button | |
414 | (let ((iterator (if (> n 0) #'next-button #'previous-button)) | |
415 | (wrap-start (if (> n 0) (point-min) (point-max)))) | |
416 | (setq n (abs n)) | |
417 | (setq button t) ; just to start the loop | |
418 | (while (and (> n 0) button) | |
419 | (setq button (funcall iterator (point))) | |
420 | (when (and (not button) wrap) | |
421 | (setq button (funcall iterator wrap-start t))) | |
422 | (when button | |
423 | (goto-char (button-start button)) | |
424 | (unless (button-get button 'skip) | |
425 | (setq n (1- n))))))) | |
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426 | (if (null button) |
427 | (error (if wrap "No buttons!" "No more buttons")) | |
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428 | (let ((msg (and display-message (button-get button 'help-echo)))) |
429 | (when msg | |
430 | (message "%s" msg))) | |
431 | button))) | |
432 | ||
433 | (defun backward-button (n &optional wrap display-message) | |
434 | "Move to the Nth previous button, or Nth next button if N is negative. | |
fee34a28 | 435 | If N is 0, move to the start of any button at point. |
0c26f463 MB |
436 | If WRAP is non-nil, moving past either end of the buffer continues from the |
437 | other end. | |
438 | If DISPLAY-MESSAGE is non-nil, the button's help-echo string is displayed. | |
fee34a28 | 439 | Any button with a non-nil `skip' property is skipped over. |
0c26f463 MB |
440 | Returns the button found." |
441 | (interactive "p\nd\nd") | |
442 | (forward-button (- n) wrap display-message)) | |
443 | ||
444 | ||
445 | (provide 'button) | |
446 | ||
447 | ;;; button.el ends here |