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c0274f38 ER |
1 | ;;; ehelp.el --- bindings for electric-help mode |
2 | ||
3a801d0c ER |
3 | ;; Copyright (C) 1986 Free Software Foundation, Inc. |
4 | ||
e5167999 | 5 | ;; Maintainer: FSF |
fd7fa35a | 6 | ;; Keywords: help, extensions |
e5167999 | 7 | |
a2535589 JA |
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 | |
e5167999 | 12 | ;; the Free Software Foundation; either version 2, or (at your option) |
a2535589 JA |
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 | |
22 | ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. | |
23 | ||
e41b2db1 ER |
24 | ;;; Commentary: |
25 | ||
26 | ;; This package provides a pre-packaged `Electric Help Mode' for | |
27 | ;; browsing on-line help screens. There is one entry point, | |
28 | ;; `with-electric-help'; All you have to give it is a no-argument | |
29 | ;; function that generates the actual text of the help into the urrent | |
30 | ;; buffer. | |
31 | ||
e5167999 ER |
32 | ;;; Code: |
33 | ||
a2535589 | 34 | (require 'electric) |
a2535589 | 35 | (defvar electric-help-map () |
d5b9d1d8 | 36 | "Keymap defining commands available in `electric-help-mode'.") |
a2535589 JA |
37 | |
38 | (put 'electric-help-undefined 'suppress-keymap t) | |
39 | (if electric-help-map | |
40 | () | |
41 | (let ((map (make-keymap))) | |
e8a57935 | 42 | (fillarray (car (cdr map)) 'electric-help-undefined) |
a2535589 JA |
43 | (define-key map (char-to-string meta-prefix-char) (copy-keymap map)) |
44 | (define-key map (char-to-string help-char) 'electric-help-help) | |
45 | (define-key map "?" 'electric-help-help) | |
46 | (define-key map " " 'scroll-up) | |
47 | (define-key map "\^?" 'scroll-down) | |
48 | (define-key map "." 'beginning-of-buffer) | |
49 | (define-key map "<" 'beginning-of-buffer) | |
50 | (define-key map ">" 'end-of-buffer) | |
51 | ;(define-key map "\C-g" 'electric-help-exit) | |
52 | (define-key map "q" 'electric-help-exit) | |
53 | (define-key map "Q" 'electric-help-exit) | |
54 | ;;a better key than this? | |
55 | (define-key map "r" 'electric-help-retain) | |
56 | ||
57 | (setq electric-help-map map))) | |
58 | ||
59 | (defun electric-help-mode () | |
d5b9d1d8 JB |
60 | "`with-electric-help' temporarily places its buffer in this mode. |
61 | \(On exit from `with-electric-help', the buffer is put in `default-major-mode'.)" | |
a2535589 JA |
62 | (setq buffer-read-only t) |
63 | (setq mode-name "Help") | |
64 | (setq major-mode 'help) | |
65 | (setq mode-line-buffer-identification '(" Help: %b")) | |
66 | (use-local-map electric-help-map) | |
67 | ;; this is done below in with-electric-help | |
68 | ;(run-hooks 'electric-help-mode-hook) | |
69 | ) | |
70 | ||
71 | (defun with-electric-help (thunk &optional buffer noerase) | |
d5b9d1d8 JB |
72 | "Arguments are THUNK &optional BUFFER NOERASE. BUFFER defaults to \"*Help*\" |
73 | THUNK is a function of no arguments which is called to initialize | |
74 | the contents of BUFFER. BUFFER will be erased before THUNK is called unless | |
75 | NOERASE is non-nil. THUNK will be called with `standard-output' bound to | |
76 | the buffer specified by BUFFER | |
a2535589 JA |
77 | |
78 | After THUNK has been called, this function \"electrically\" pops up a window | |
79 | in which BUFFER is displayed and allows the user to scroll through that buffer | |
80 | in electric-help-mode. | |
d5b9d1d8 JB |
81 | When the user exits (with `electric-help-exit', or otherwise) the help |
82 | buffer's window disappears (i.e., we use `save-window-excursion') | |
83 | BUFFER is put into `default-major-mode' (or `fundamental-mode') when we exit" | |
a2535589 JA |
84 | (setq buffer (get-buffer-create (or buffer "*Help*"))) |
85 | (let ((one (one-window-p t)) | |
88c269cb | 86 | (config (current-window-configuration)) |
87 | (bury nil)) | |
88 | (unwind-protect | |
89 | (save-excursion | |
90 | (if one (goto-char (window-start (selected-window)))) | |
91 | (let ((pop-up-windows t)) | |
92 | (pop-to-buffer buffer)) | |
93 | (save-excursion | |
94 | (set-buffer buffer) | |
95 | (electric-help-mode) | |
96 | (setq buffer-read-only nil) | |
97 | (or noerase (erase-buffer))) | |
98 | (let ((standard-output buffer)) | |
99 | (if (not (funcall thunk)) | |
100 | (progn | |
101 | (set-buffer buffer) | |
102 | (set-buffer-modified-p nil) | |
103 | (goto-char (point-min)) | |
104 | (if one (shrink-window-if-larger-than-buffer (selected-window)))))) | |
105 | (set-buffer buffer) | |
106 | (run-hooks 'electric-help-mode-hook) | |
107 | (if (eq (car-safe (electric-help-command-loop)) | |
108 | 'retain) | |
109 | (setq config (current-window-configuration)) | |
110 | (setq bury t))) | |
111 | (message "") | |
112 | (set-buffer buffer) | |
113 | (setq buffer-read-only nil) | |
114 | (condition-case () | |
115 | (funcall (or default-major-mode 'fundamental-mode)) | |
116 | (error nil)) | |
117 | (set-window-configuration config) | |
118 | (if bury | |
119 | (progn | |
120 | ;;>> Perhaps this shouldn't be done. | |
121 | ;; so that when we say "Press space to bury" we mean it | |
122 | (replace-buffer-in-windows buffer) | |
123 | ;; must do this outside of save-window-excursion | |
124 | (bury-buffer buffer)))))) | |
a2535589 JA |
125 | |
126 | (defun electric-help-command-loop () | |
127 | (catch 'exit | |
128 | (if (pos-visible-in-window-p (point-max)) | |
129 | (progn (message "<<< Press Space to bury the help buffer >>>") | |
07f6d4ae | 130 | (if (eq (setq unread-command-events (list (read-event))) ?\ ) |
dbc4e1c1 | 131 | (progn (setq unread-command-events nil) |
a2535589 JA |
132 | (throw 'exit t))))) |
133 | (let (up down both neither | |
134 | (standard (and (eq (key-binding " ") | |
135 | 'scroll-up) | |
136 | (eq (key-binding "\^?") | |
137 | 'scroll-down) | |
138 | (eq (key-binding "Q") | |
139 | 'electric-help-exit) | |
140 | (eq (key-binding "q") | |
141 | 'electric-help-exit)))) | |
142 | (Electric-command-loop | |
143 | 'exit | |
144 | (function (lambda () | |
145 | (let ((min (pos-visible-in-window-p (point-min))) | |
146 | (max (pos-visible-in-window-p (point-max)))) | |
147 | (cond ((and min max) | |
148 | (cond (standard "Press Q to exit ") | |
149 | (neither) | |
150 | (t (setq neither (substitute-command-keys "Press \\[scroll-up] to exit "))))) | |
151 | (min | |
152 | (cond (standard "Press SPC to scroll, Q to exit ") | |
153 | (up) | |
154 | (t (setq up (substitute-command-keys "Press \\[scroll-up] to scroll; \\[electric-help-exit] to exit "))))) | |
155 | (max | |
156 | (cond (standard "Press DEL to scroll back, Q to exit ") | |
157 | (down) | |
158 | (t (setq down (substitute-command-keys "Press \\[scroll-down] to scroll back, \\[scroll-up] to exit "))))) | |
159 | (t | |
160 | (cond (standard "Press SPC to scroll, DEL to scroll back, Q to exit ") | |
161 | (both) | |
162 | (t (setq both (substitute-command-keys "Press \\[scroll-up] to scroll, \\[scroll-down] to scroll back, \\[electric-help-exit] to exit "))))))))) | |
163 | t)))) | |
164 | ||
165 | ||
166 | \f | |
167 | ;(defun electric-help-scroll-up (arg) | |
168 | ; ">>>Doc" | |
169 | ; (interactive "P") | |
170 | ; (if (and (null arg) (pos-visible-in-window-p (point-max))) | |
171 | ; (electric-help-exit) | |
172 | ; (scroll-up arg))) | |
173 | ||
174 | (defun electric-help-exit () | |
175 | ">>>Doc" | |
176 | (interactive) | |
177 | (throw 'exit t)) | |
178 | ||
179 | (defun electric-help-retain () | |
d5b9d1d8 | 180 | "Exit `electric-help', retaining the current window/buffer configuration. |
a2535589 JA |
181 | \(The *Help* buffer will not be selected, but \\[switch-to-buffer-other-window] RET |
182 | will select it.)" | |
183 | (interactive) | |
184 | (throw 'exit '(retain))) | |
185 | ||
186 | ||
a2535589 JA |
187 | (defun electric-help-undefined () |
188 | (interactive) | |
189 | (error "%s is undefined -- Press %s to exit" | |
190 | (mapconcat 'single-key-description (this-command-keys) " ") | |
191 | (if (eq (key-binding "Q") 'electric-help-exit) | |
192 | "Q" | |
193 | (substitute-command-keys "\\[electric-help-exit]")))) | |
194 | ||
195 | ||
196 | ;>>> this needs to be hairified (recursive help, anybody?) | |
197 | (defun electric-help-help () | |
198 | (interactive) | |
199 | (if (and (eq (key-binding "Q") 'electric-help-exit) | |
200 | (eq (key-binding " ") 'scroll-up) | |
201 | (eq (key-binding "\^?") 'scroll-down)) | |
202 | (message "SPC scrolls forward, DEL scrolls back, Q exits and burys help buffer") | |
203 | ;; to give something for user to look at while slow substitute-cmd-keys | |
204 | ;; grinds away | |
205 | (message "Help...") | |
206 | (message "%s" (substitute-command-keys "\\[scroll-up] scrolls forward, \\[scroll-down] scrolls back, \\[electric-help-exit] exits."))) | |
207 | (sit-for 2)) | |
208 | ||
209 | \f | |
210 | (defun electric-helpify (fun) | |
211 | (let ((name "*Help*")) | |
212 | (if (save-window-excursion | |
213 | ;; kludge-o-rama | |
214 | (let* ((p (symbol-function 'print-help-return-message)) | |
215 | (b (get-buffer name)) | |
216 | (m (buffer-modified-p b))) | |
217 | (and b (not (get-buffer-window b)) | |
218 | (setq b nil)) | |
219 | (unwind-protect | |
220 | (progn | |
221 | (message "%s..." (capitalize (symbol-name fun))) | |
222 | ;; with-output-to-temp-buffer marks the buffer as unmodified. | |
223 | ;; kludging excessively and relying on that as some sort | |
224 | ;; of indication leads to the following abomination... | |
225 | ;;>> This would be doable without such icky kludges if either | |
226 | ;;>> (a) there were a function to read the interactive | |
227 | ;;>> args for a command and return a list of those args. | |
228 | ;;>> (To which one would then just apply the command) | |
229 | ;;>> (The only problem with this is that interactive-p | |
230 | ;;>> would break, but that is such a misfeature in | |
231 | ;;>> any case that I don't care) | |
232 | ;;>> It is easy to do this for emacs-lisp functions; | |
233 | ;;>> the only problem is getting the interactive spec | |
234 | ;;>> for subrs | |
235 | ;;>> (b) there were a function which returned a | |
236 | ;;>> modification-tick for a buffer. One could tell | |
237 | ;;>> whether a buffer had changed by whether the | |
238 | ;;>> modification-tick were different. | |
239 | ;;>> (Presumably there would have to be a way to either | |
240 | ;;>> restore the tick to some previous value, or to | |
241 | ;;>> suspend updating of the tick in order to allow | |
242 | ;;>> things like momentary-string-display) | |
243 | (and b | |
244 | (save-excursion | |
245 | (set-buffer b) | |
246 | (set-buffer-modified-p t))) | |
247 | (fset 'print-help-return-message 'ignore) | |
248 | (call-interactively fun) | |
249 | (and (get-buffer name) | |
250 | (get-buffer-window (get-buffer name)) | |
251 | (or (not b) | |
252 | (not (eq b (get-buffer name))) | |
253 | (not (buffer-modified-p b))))) | |
254 | (fset 'print-help-return-message p) | |
255 | (and b (buffer-name b) | |
256 | (save-excursion | |
257 | (set-buffer b) | |
258 | (set-buffer-modified-p m)))))) | |
259 | (with-electric-help 'ignore name t)))) | |
260 | ||
261 | \f | |
262 | (defun electric-describe-key () | |
263 | (interactive) | |
264 | (electric-helpify 'describe-key)) | |
265 | ||
266 | (defun electric-describe-mode () | |
267 | (interactive) | |
268 | (electric-helpify 'describe-mode)) | |
269 | ||
270 | (defun electric-view-lossage () | |
271 | (interactive) | |
272 | (electric-helpify 'view-lossage)) | |
273 | ||
274 | ;(defun electric-help-for-help () | |
275 | ; "See help-for-help" | |
276 | ; (interactive) | |
277 | ; ) | |
278 | ||
279 | (defun electric-describe-function () | |
280 | (interactive) | |
281 | (electric-helpify 'describe-function)) | |
282 | ||
283 | (defun electric-describe-variable () | |
284 | (interactive) | |
285 | (electric-helpify 'describe-variable)) | |
286 | ||
287 | (defun electric-describe-bindings () | |
288 | (interactive) | |
289 | (electric-helpify 'describe-bindings)) | |
290 | ||
291 | (defun electric-describe-syntax () | |
292 | (interactive) | |
293 | (electric-helpify 'describe-syntax)) | |
294 | ||
295 | (defun electric-command-apropos () | |
296 | (interactive) | |
297 | (electric-helpify 'command-apropos)) | |
298 | ||
299 | ;(define-key help-map "a" 'electric-command-apropos) | |
300 | ||
301 | ||
a2535589 JA |
302 | \f |
303 | ;;;; ehelp-map | |
304 | ||
305 | (defvar ehelp-map ()) | |
306 | (if ehelp-map | |
307 | nil | |
308 | (let ((map (copy-keymap help-map))) | |
309 | (substitute-key-definition 'describe-key 'electric-describe-key map) | |
310 | (substitute-key-definition 'describe-mode 'electric-describe-mode map) | |
311 | (substitute-key-definition 'view-lossage 'electric-view-lossage map) | |
312 | (substitute-key-definition 'describe-function 'electric-describe-function map) | |
313 | (substitute-key-definition 'describe-variable 'electric-describe-variable map) | |
314 | (substitute-key-definition 'describe-bindings 'electric-describe-bindings map) | |
315 | (substitute-key-definition 'describe-syntax 'electric-describe-syntax map) | |
316 | ||
317 | (setq ehelp-map map) | |
318 | (fset 'ehelp-command map))) | |
319 | ||
320 | ;; Do (define-key global-map "\C-h" 'ehelp-command) if you want to win | |
49116ac0 JB |
321 | |
322 | (provide 'ehelp) | |
323 | ||
c0274f38 | 324 | ;;; ehelp.el ends here |