* frame.el (special-display-popup-frame): Doc fix (Bug#8853).
[emacs.git] / lisp / ehelp.el
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1 ;;; ehelp.el --- bindings for electric-help mode
3 ;; Copyright (C) 1986, 1995, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
4 ;; 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
6 ;; Author: Richard Mlynarik
7 ;; (according to ack.texi and authors.el)
8 ;; Maintainer: FSF
9 ;; Keywords: help, extensions
11 ;; This file is part of GNU Emacs.
13 ;; GNU Emacs is free software: you can redistribute it and/or modify
14 ;; it under the terms of the GNU General Public License as published by
15 ;; the Free Software Foundation, either version 3 of the License, or
16 ;; (at your option) any later version.
18 ;; GNU Emacs is distributed in the hope that it will be useful,
19 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 ;; GNU General Public License for more details.
23 ;; You should have received a copy of the GNU General Public License
24 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
26 ;;; Commentary:
28 ;; This package provides a pre-packaged `Electric Help Mode' for
29 ;; browsing on-line help screens. There is one entry point,
30 ;; `with-electric-help'; all you have to give it is a no-argument
31 ;; function that generates the actual text of the help into the current
32 ;; buffer.
34 ;; To make this the default, you must do
35 ;; (require 'ehelp)
36 ;; (define-key global-map "\C-h" 'ehelp-command)
37 ;; (define-key global-map [help] 'ehelp-command)
38 ;; (define-key global-map [f1] 'ehelp-command)
40 ;;; Code:
42 (require 'electric)
44 (defvar electric-help-form-to-execute nil)
46 (defgroup electric-help ()
47 "Electric help facility."
48 :version "21.1"
49 :group 'help)
51 (defcustom electric-help-shrink-window t
52 "If set, adjust help window sizes to buffer sizes when displaying help."
53 :type 'boolean
54 :group 'electric-help)
56 (defcustom electric-help-mode-hook nil
57 "Hook run by `with-electric-help' after initializing the buffer."
58 :type 'hook
59 :group 'electric-help)
61 (put 'electric-help-undefined 'suppress-keymap t)
63 (defvar electric-help-map
64 (let ((map (make-keymap)))
65 ;; allow all non-self-inserting keys - search, scroll, etc, but
66 ;; let M-x and C-x exit ehelp mode and retain buffer:
67 (suppress-keymap map)
68 (define-key map "\C-u" 'electric-help-undefined)
69 (define-key map [?\C-0] 'electric-help-undefined)
70 (define-key map [?\C-1] 'electric-help-undefined)
71 (define-key map [?\C-2] 'electric-help-undefined)
72 (define-key map [?\C-3] 'electric-help-undefined)
73 (define-key map [?\C-4] 'electric-help-undefined)
74 (define-key map [?\C-5] 'electric-help-undefined)
75 (define-key map [?\C-6] 'electric-help-undefined)
76 (define-key map [?\C-7] 'electric-help-undefined)
77 (define-key map [?\C-8] 'electric-help-undefined)
78 (define-key map [?\C-9] 'electric-help-undefined)
79 (define-key map (char-to-string help-char) 'electric-help-help)
80 (define-key map "?" 'electric-help-help)
81 (define-key map " " 'scroll-up)
82 (define-key map "\^?" 'scroll-down)
83 (define-key map "." 'beginning-of-buffer)
84 (define-key map "<" 'beginning-of-buffer)
85 (define-key map ">" 'end-of-buffer)
86 ;(define-key map "\C-g" 'electric-help-exit)
87 (define-key map "Q" 'electric-help-exit)
88 (define-key map "q" 'electric-help-exit)
89 ;;a better key than this?
90 (define-key map "R" 'electric-help-retain)
91 (define-key map "r" 'electric-help-retain)
92 (define-key map "\ex" 'electric-help-execute-extended)
93 (define-key map "\C-x" 'electric-help-ctrl-x-prefix)
94 map)
95 "Keymap defining commands available in `electric-help-mode'.")
97 (defun electric-help-mode ()
98 "`with-electric-help' temporarily places its buffer in this mode.
99 \(On exit from `with-electric-help', the buffer is put in default `major-mode'.)"
100 (setq buffer-read-only t)
101 (setq mode-name "Help")
102 (setq major-mode 'help)
103 (setq mode-line-buffer-identification '(" Help: %b"))
104 (use-local-map electric-help-map)
105 (add-hook 'mouse-leave-buffer-hook 'electric-help-retain)
106 (view-mode -1)
107 ;; this is done below in with-electric-help
108 ;(run-hooks 'electric-help-mode-hook)
111 ;;;###autoload
112 (defun with-electric-help (thunk &optional buffer noerase minheight)
113 "Pop up an \"electric\" help buffer.
114 THUNK is a function of no arguments which is called to initialize the
115 contents of BUFFER. BUFFER defaults to `*Help*'. BUFFER will be
116 erased before THUNK is called unless NOERASE is non-nil. THUNK will
117 be called while BUFFER is current and with `standard-output' bound to
118 the buffer specified by BUFFER.
120 If THUNK returns nil, we display BUFFER starting at the top, and shrink
121 the window to fit. If THUNK returns non-nil, we don't do those things.
123 After THUNK has been called, this function \"electrically\" pops up a
124 window in which BUFFER is displayed and allows the user to scroll
125 through that buffer in `electric-help-mode'. The window's height will
126 be at least MINHEIGHT if this value is non-nil.
128 If THUNK returns nil, we display BUFFER starting at the top, and
129 shrink the window to fit if `electric-help-shrink-window' is non-nil.
130 If THUNK returns non-nil, we don't do those things.
132 When the user exits (with `electric-help-exit', or otherwise), the help
133 buffer's window disappears (i.e., we use `save-window-excursion'), and
134 BUFFER is put into default `major-mode' (or `fundamental-mode')."
135 (setq buffer (get-buffer-create (or buffer "*Help*")))
136 (let ((one (one-window-p t))
137 (config (current-window-configuration))
138 (bury nil)
139 (electric-help-form-to-execute nil))
140 (unwind-protect
141 (save-excursion
142 (when one
143 (goto-char (window-start (selected-window))))
144 (let ((pop-up-windows t))
145 (pop-to-buffer buffer))
146 (with-current-buffer buffer
147 (when (and minheight (< (window-height) minheight))
148 (enlarge-window (- minheight (window-height))))
149 (electric-help-mode)
150 (setq buffer-read-only nil)
151 (unless noerase
152 (erase-buffer)))
153 (let ((standard-output buffer))
154 (unless (funcall thunk)
155 (set-buffer buffer)
156 (set-buffer-modified-p nil)
157 (goto-char (point-min))
158 (when (and one electric-help-shrink-window)
159 (shrink-window-if-larger-than-buffer))))
160 (set-buffer buffer)
161 (run-hooks 'electric-help-mode-hook)
162 (setq buffer-read-only t)
163 (if (eq (car-safe (electric-help-command-loop)) 'retain)
164 (setq config (current-window-configuration))
165 (setq bury t))
166 ;; Remove the hook.
167 (when (memq 'electric-help-retain mouse-leave-buffer-hook)
168 (remove-hook 'mouse-leave-buffer-hook 'electric-help-retain)))
169 (message "")
170 (set-buffer buffer)
171 (setq buffer-read-only nil)
173 ;; We should really get a usable *Help* buffer when retaining
174 ;; the electric one with `r'. The problem is that a simple
175 ;; call to help-mode won't cut it; at least RET is bound wrong
176 ;; afterwards. It's also not clear that `help-mode' is always
177 ;; the right thing, maybe we should add an optional parameter.
178 (condition-case ()
179 (funcall (or (default-value 'major-mode) 'fundamental-mode))
180 (error nil))
182 (set-window-configuration config)
183 (when bury
184 ;;>> Perhaps this shouldn't be done,
185 ;; so that when we say "Press space to bury" we mean it
186 (replace-buffer-in-windows buffer)
187 ;; must do this outside of save-window-excursion
188 (bury-buffer buffer))
189 (eval electric-help-form-to-execute))))
191 (defun electric-help-command-loop ()
192 (catch 'exit
193 (if (pos-visible-in-window-p (point-max))
194 (progn (message "%s" (substitute-command-keys "<<< Press Space to bury the help buffer, Press \\[electric-help-retain] to retain it >>>"))
195 (if (equal (setq unread-command-events (list (read-event)))
196 '(?\s))
197 (progn (setq unread-command-events nil)
198 (throw 'exit t)))))
199 (let (up down both neither
200 (standard (and (eq (key-binding " " nil t)
201 'scroll-up)
202 (eq (key-binding "\^?" nil t)
203 'scroll-down)
204 (eq (key-binding "q" nil t)
205 'electric-help-exit)
206 (eq (key-binding "r" nil t)
207 'electric-help-retain))))
208 (Electric-command-loop
209 'exit
210 (function (lambda ()
211 (sit-for 0) ;necessary if last command was end-of-buffer or
212 ;beginning-of-buffer - otherwise pos-visible-in-window-p
213 ;will yield a wrong result.
214 (let ((min (pos-visible-in-window-p (point-min)))
215 (max (pos-visible-in-window-p (1- (point-max)))))
216 (cond (isearch-mode 'noprompt)
217 ((and min max)
218 (cond (standard "Press q to exit, r to retain ")
219 (neither)
220 (t (setq neither (substitute-command-keys "Press \\[electric-help-exit] to exit, \\[electric-help-retain] to retain ")))))
221 (min
222 (cond (standard "Press SPC to scroll, q to exit, r to retain ")
223 (up)
224 (t (setq up (substitute-command-keys "Press \\[scroll-up] to scroll, \\[electric-help-exit] to exit, \\[electric-help-retain] to retain ")))))
225 (max
226 (cond (standard "Press DEL to scroll back, q to exit, r to retain ")
227 (down)
228 (t (setq down (substitute-command-keys "Press \\[scroll-down] to scroll back, \\[electric-help-exit] to exit, \\[electric-help-retain] to retain ")))))
230 (cond (standard "Press SPC to scroll, DEL to scroll back, q to exit, r to retain ")
231 (both)
232 (t (setq both (substitute-command-keys "Press \\[scroll-up] to scroll, \\[scroll-down] to scroll back, \\[electric-help-exit] to exit, \\[electric-help-retain] to retain ")))))))))
233 t))))
237 ;(defun electric-help-scroll-up (arg)
238 ; ">>>Doc"
239 ; (interactive "P")
240 ; (if (and (null arg) (pos-visible-in-window-p (point-max)))
241 ; (electric-help-exit)
242 ; (scroll-up arg)))
244 (defun electric-help-exit ()
245 "Exit `with-electric-help', restoring the previous window/buffer configuration.
246 \(The *Help* buffer will be buried.)"
247 (interactive)
248 ;; Make sure that we don't throw twice, even if two events cause
249 ;; calling this function:
250 (if (memq 'electric-help-retain mouse-leave-buffer-hook)
251 (progn
252 (remove-hook 'mouse-leave-buffer-hook 'electric-help-retain)
253 (throw 'exit t))))
255 (defun electric-help-retain ()
256 "Exit `with-electric-help', retaining the current window/buffer configuration.
257 \(The *Help* buffer will not be selected, but \\[switch-to-buffer-other-window] RET
258 will select it.)"
259 (interactive)
260 ;; Make sure that we don't throw twice, even if two events cause
261 ;; calling this function:
262 (if (memq 'electric-help-retain mouse-leave-buffer-hook)
263 (progn
264 (remove-hook 'mouse-leave-buffer-hook 'electric-help-retain)
265 (throw 'exit '(retain)))))
268 (defun electric-help-undefined ()
269 (interactive)
270 (error "%s is undefined -- Press %s to exit"
271 (mapconcat 'single-key-description (this-command-keys) " ")
272 (if (eq (key-binding "q" nil t) 'electric-help-exit)
274 (substitute-command-keys "\\[electric-help-exit]"))))
277 ;>>> this needs to be hairified (recursive help, anybody?)
278 (defun electric-help-help ()
279 (interactive)
280 (if (and (eq (key-binding "q" nil t) 'electric-help-exit)
281 (eq (key-binding " " nil t) 'scroll-up)
282 (eq (key-binding "\^?" nil t) 'scroll-down)
283 (eq (key-binding "r" nil t) 'electric-help-retain))
284 (message "SPC scrolls up, DEL scrolls down, q exits burying help buffer, r exits")
285 (message "%s" (substitute-command-keys "\\[scroll-up] scrolls up, \\[scroll-down] scrolls down, \\[electric-help-exit] exits burying help buffer, \\[electric-help-retain] exits")))
286 (sit-for 2))
289 ;;;###autoload
290 (defun electric-helpify (fun &optional name)
291 (let ((name (or name "*Help*")))
292 (if (save-window-excursion
293 ;; kludge-o-rama
294 (let* ((p (symbol-function 'help-print-return-message))
295 (b (get-buffer name))
296 (m (buffer-modified-p b)))
297 (and b (not (get-buffer-window b))
298 (setq b nil))
299 (unwind-protect
300 (progn
301 (message "%s..." (capitalize (symbol-name fun)))
302 ;; with-output-to-temp-buffer marks the buffer as unmodified.
303 ;; kludging excessively and relying on that as some sort
304 ;; of indication leads to the following abomination...
305 ;;>> This would be doable without such icky kludges if either
306 ;;>> (a) there were a function to read the interactive
307 ;;>> args for a command and return a list of those args.
308 ;;>> (To which one would then just apply the command)
309 ;;>> (The only problem with this is that interactive-p
310 ;;>> would break, but that is such a misfeature in
311 ;;>> any case that I don't care)
312 ;;>> It is easy to do this for emacs-lisp functions;
313 ;;>> the only problem is getting the interactive spec
314 ;;>> for subrs
315 ;;>> (b) there were a function which returned a
316 ;;>> modification-tick for a buffer. One could tell
317 ;;>> whether a buffer had changed by whether the
318 ;;>> modification-tick were different.
319 ;;>> (Presumably there would have to be a way to either
320 ;;>> restore the tick to some previous value, or to
321 ;;>> suspend updating of the tick in order to allow
322 ;;>> things like momentary-string-display)
323 (and b
324 (with-current-buffer b
325 (set-buffer-modified-p t)))
326 (fset 'help-print-return-message 'ignore)
327 (call-interactively fun)
328 (and (get-buffer name)
329 (get-buffer-window (get-buffer name))
330 (or (not b)
331 (not (eq b (get-buffer name)))
332 (not (buffer-modified-p b)))))
333 (fset 'help-print-return-message p)
334 (and b (buffer-name b)
335 (with-current-buffer b
336 (set-buffer-modified-p m))))))
337 (with-electric-help 'ignore name t))))
341 ;; This is to be bound to M-x in ehelp mode. Retains ehelp buffer and then
342 ;; continues with execute-extended-command.
343 (defun electric-help-execute-extended (prefixarg)
344 (interactive "p")
345 (setq electric-help-form-to-execute '(execute-extended-command nil))
346 (electric-help-retain))
348 ;; This is to be buond to C-x in ehelp mode. Retains ehelp buffer and then
349 ;; continues with ctrl-x prefix.
350 (defun electric-help-ctrl-x-prefix (prefixarg)
351 (interactive "p")
352 (setq electric-help-form-to-execute '(progn (message nil) (setq unread-command-char ?\C-x)))
353 (electric-help-retain))
356 (defun electric-describe-key ()
357 (interactive)
358 (electric-helpify 'describe-key))
360 (defun electric-describe-mode ()
361 (interactive)
362 (electric-helpify 'describe-mode))
364 (defun electric-view-lossage ()
365 (interactive)
366 (electric-helpify 'view-lossage))
368 ;(defun electric-help-for-help ()
369 ; "See help-for-help"
370 ; (interactive)
373 (defun electric-describe-function ()
374 (interactive)
375 (electric-helpify 'describe-function))
377 (defun electric-describe-variable ()
378 (interactive)
379 (electric-helpify 'describe-variable))
381 (defun electric-describe-bindings ()
382 (interactive)
383 (electric-helpify 'describe-bindings))
385 (defun electric-describe-syntax ()
386 (interactive)
387 (electric-helpify 'describe-syntax))
389 (defun electric-command-apropos ()
390 (interactive)
391 (electric-helpify 'command-apropos "*Apropos*"))
393 ;(define-key help-map "a" 'electric-command-apropos)
395 (defun electric-apropos ()
396 (interactive)
397 (electric-helpify 'apropos))
400 ;;;; ehelp-map
402 (defvar ehelp-map
403 (let ((map (copy-keymap help-map)))
404 (substitute-key-definition 'apropos 'electric-apropos map)
405 (substitute-key-definition 'command-apropos 'electric-command-apropos map)
406 (substitute-key-definition 'describe-key 'electric-describe-key map)
407 (substitute-key-definition 'describe-mode 'electric-describe-mode map)
408 (substitute-key-definition 'view-lossage 'electric-view-lossage map)
409 (substitute-key-definition 'describe-function 'electric-describe-function map)
410 (substitute-key-definition 'describe-variable 'electric-describe-variable map)
411 (substitute-key-definition 'describe-bindings 'electric-describe-bindings map)
412 (substitute-key-definition 'describe-syntax 'electric-describe-syntax map)
413 map))
415 ;;;###(autoload 'ehelp-command "ehelp" "Prefix command for ehelp." t 'keymap)
416 (defalias 'ehelp-command ehelp-map)
417 (put 'ehelp-command 'documentation "Prefix command for ehelp.")
419 (provide 'ehelp)
421 ;; arch-tag: e0e3037f-42c0-433e-ba18-322c5d951f46
422 ;;; ehelp.el ends here