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1 | ;;; help.el --- help commands for Emacs |
2 | ||
e5167999 ER |
3 | ;; Maintainer: FSF |
4 | ;; Last-Modified: 30 Jun 1992 | |
5 | ||
433ae6f6 RS |
6 | ;; Copyright (C) 1985, 1986 Free Software Foundation, Inc. |
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 | |
e5167999 | 12 | ;; the Free Software Foundation; either version 2, or (at your option) |
433ae6f6 RS |
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 | ||
e5167999 ER |
24 | ;;; Code: |
25 | ||
433ae6f6 RS |
26 | (defvar help-map (make-sparse-keymap) |
27 | "Keymap for characters following the Help key.") | |
28 | ||
29 | (define-key global-map "\C-h" 'help-command) | |
30 | (fset 'help-command help-map) | |
31 | ||
32 | (define-key help-map "\C-h" 'help-for-help) | |
33 | (define-key help-map "?" 'help-for-help) | |
34 | ||
35 | (define-key help-map "\C-c" 'describe-copying) | |
36 | (define-key help-map "\C-d" 'describe-distribution) | |
37 | (define-key help-map "\C-w" 'describe-no-warranty) | |
38 | (define-key help-map "a" 'command-apropos) | |
39 | ||
40 | (define-key help-map "b" 'describe-bindings) | |
41 | ||
42 | (define-key help-map "c" 'describe-key-briefly) | |
43 | (define-key help-map "k" 'describe-key) | |
44 | ||
45 | (define-key help-map "d" 'describe-function) | |
46 | (define-key help-map "f" 'describe-function) | |
47 | ||
48 | (define-key help-map "i" 'info) | |
e5d77022 JB |
49 | (define-key help-map "\C-f" 'Info-goto-emacs-command-node) |
50 | (define-key help-map "\C-k" 'Info-goto-emacs-key-command-node) | |
433ae6f6 RS |
51 | |
52 | (define-key help-map "l" 'view-lossage) | |
53 | ||
54 | (define-key help-map "m" 'describe-mode) | |
55 | ||
56 | (define-key help-map "\C-n" 'view-emacs-news) | |
57 | (define-key help-map "n" 'view-emacs-news) | |
58 | ||
59 | (define-key help-map "s" 'describe-syntax) | |
60 | ||
61 | (define-key help-map "t" 'help-with-tutorial) | |
62 | ||
63 | (define-key help-map "w" 'where-is) | |
64 | ||
65 | (define-key help-map "v" 'describe-variable) | |
66 | ||
67 | (defun help-with-tutorial () | |
68 | "Select the Emacs learn-by-doing tutorial." | |
69 | (interactive) | |
70 | (let ((file (expand-file-name "~/TUTORIAL"))) | |
71 | (delete-other-windows) | |
72 | (if (get-file-buffer file) | |
73 | (switch-to-buffer (get-file-buffer file)) | |
74 | (switch-to-buffer (create-file-buffer file)) | |
75 | (setq buffer-file-name file) | |
76 | (setq default-directory (expand-file-name "~/")) | |
79058860 | 77 | (setq buffer-auto-save-file-name nil) |
1e6dacf6 | 78 | (insert-file-contents (expand-file-name "TUTORIAL" data-directory)) |
433ae6f6 RS |
79 | (goto-char (point-min)) |
80 | (search-forward "\n<<") | |
81 | (beginning-of-line) | |
82 | (delete-region (point) (progn (end-of-line) (point))) | |
83 | (newline (- (window-height (selected-window)) | |
84 | (count-lines (point-min) (point)) | |
85 | 6)) | |
86 | (goto-char (point-min)) | |
87 | (set-buffer-modified-p nil)))) | |
88 | ||
89 | (defun describe-key-briefly (key) | |
90 | "Print the name of the function KEY invokes. KEY is a string." | |
91 | (interactive "kDescribe key briefly: ") | |
92 | (let ((defn (key-binding key))) | |
93 | (if (or (null defn) (integerp defn)) | |
94 | (message "%s is undefined" (key-description key)) | |
95 | (message "%s runs the command %s" | |
96 | (key-description key) | |
97 | (if (symbolp defn) defn (prin1-to-string defn)))))) | |
98 | ||
99 | (defun print-help-return-message (&optional function) | |
100 | "Display or return message saying how to restore windows after help command. | |
101 | Computes a message and applies the optional argument FUNCTION to it. | |
102 | If FUNCTION is nil, applies `message' to it, thus printing it." | |
103 | (and (not (get-buffer-window standard-output)) | |
104 | (funcall (or function 'message) | |
105 | (concat | |
106 | (substitute-command-keys | |
107 | (if (one-window-p t) | |
108 | (if pop-up-windows | |
109 | "Type \\[delete-other-windows] to remove help window." | |
110 | "Type \\[switch-to-buffer] RET to remove help window.") | |
111 | "Type \\[switch-to-buffer-other-window] RET to restore the other window.")) | |
112 | (substitute-command-keys | |
113 | " \\[scroll-other-window] to scroll the help."))))) | |
114 | ||
115 | (defun describe-key (key) | |
116 | "Display documentation of the function invoked by KEY. KEY is a string." | |
117 | (interactive "kDescribe key: ") | |
118 | (let ((defn (key-binding key))) | |
119 | (if (or (null defn) (integerp defn)) | |
120 | (message "%s is undefined" (key-description key)) | |
121 | (with-output-to-temp-buffer "*Help*" | |
122 | (prin1 defn) | |
123 | (princ ":\n") | |
124 | (if (documentation defn) | |
125 | (princ (documentation defn)) | |
126 | (princ "not documented")) | |
127 | (print-help-return-message))))) | |
128 | ||
129 | (defun describe-mode (&optional minor) | |
130 | "Display documentation of current major mode. | |
131 | If optional MINOR is non-nil (or prefix argument is given if interactive), | |
132 | display documentation of active minor modes as well. | |
133 | For this to work correctly for a minor mode, the mode's indicator variable | |
134 | (listed in `minor-mode-alist') must also be a function whose documentation | |
135 | describes the minor mode." | |
136 | (interactive) | |
137 | (with-output-to-temp-buffer "*Help*" | |
138 | (princ mode-name) | |
139 | (princ " Mode:\n") | |
140 | (princ (documentation major-mode)) | |
141 | (let ((minor-modes minor-mode-alist) | |
142 | (locals (buffer-local-variables))) | |
143 | (while minor-modes | |
144 | (let* ((minor-mode (car (car minor-modes))) | |
145 | (indicator (car (cdr (car minor-modes)))) | |
146 | (local-binding (assq minor-mode locals))) | |
147 | ;; Document a minor mode if it is listed in minor-mode-alist, | |
148 | ;; bound locally in this buffer, non-nil, and has a function | |
149 | ;; definition. | |
150 | (if (and local-binding | |
151 | (cdr local-binding) | |
152 | (fboundp minor-mode)) | |
153 | (progn | |
154 | (princ (format "\n\n\n%s minor mode (indicator%s):\n" | |
155 | minor-mode indicator)) | |
156 | (princ (documentation minor-mode))))) | |
157 | (setq minor-modes (cdr minor-modes)))) | |
158 | (print-help-return-message))) | |
159 | ||
160 | ;; So keyboard macro definitions are documented correctly | |
161 | (fset 'defining-kbd-macro (symbol-function 'start-kbd-macro)) | |
162 | ||
163 | (defun describe-distribution () | |
164 | "Display info on how to obtain the latest version of GNU Emacs." | |
165 | (interactive) | |
166 | (find-file-read-only | |
1e6dacf6 | 167 | (expand-file-name "DISTRIB" data-directory))) |
433ae6f6 RS |
168 | |
169 | (defun describe-copying () | |
170 | "Display info on how you may redistribute copies of GNU Emacs." | |
171 | (interactive) | |
172 | (find-file-read-only | |
1e6dacf6 | 173 | (expand-file-name "COPYING" data-directory)) |
433ae6f6 RS |
174 | (goto-char (point-min))) |
175 | ||
176 | (defun describe-no-warranty () | |
177 | "Display info on all the kinds of warranty Emacs does NOT have." | |
178 | (interactive) | |
179 | (describe-copying) | |
180 | (let (case-fold-search) | |
181 | (search-forward "NO WARRANTY") | |
182 | (recenter 0))) | |
183 | ||
184 | (defun view-emacs-news () | |
185 | "Display info on recent changes to Emacs." | |
186 | (interactive) | |
1e6dacf6 | 187 | (find-file-read-only (expand-file-name "NEWS" data-directory))) |
433ae6f6 RS |
188 | |
189 | (defun view-lossage () | |
190 | "Display last 100 input keystrokes." | |
191 | (interactive) | |
192 | (with-output-to-temp-buffer "*Help*" | |
193 | (princ (key-description (recent-keys))) | |
194 | (save-excursion | |
195 | (set-buffer standard-output) | |
196 | (goto-char (point-min)) | |
197 | (while (progn (move-to-column 50) (not (eobp))) | |
198 | (search-forward " " nil t) | |
199 | (insert "\n"))) | |
200 | (print-help-return-message))) | |
201 | ||
202 | (defun help-for-help () | |
203 | "You have typed C-h, the help character. Type a Help option: | |
204 | ||
205 | A command-apropos. Give a substring, and see a list of commands | |
206 | (functions interactively callable) that contain | |
207 | that substring. See also the apropos command. | |
208 | B describe-bindings. Display table of all key bindings. | |
209 | C describe-key-briefly. Type a command key sequence; | |
210 | it prints the function name that sequence runs. | |
211 | F describe-function. Type a function name and get documentation of it. | |
212 | I info. The info documentation reader. | |
213 | K describe-key. Type a command key sequence; | |
214 | it displays the full documentation. | |
215 | L view-lossage. Shows last 100 characters you typed. | |
216 | M describe-mode. Print documentation of current major mode, | |
217 | which describes the commands peculiar to it. | |
218 | N view-emacs-news. Shows emacs news file. | |
219 | S describe-syntax. Display contents of syntax table, plus explanations | |
220 | T help-with-tutorial. Select the Emacs learn-by-doing tutorial. | |
221 | V describe-variable. Type name of a variable; | |
222 | it displays the variable's documentation and value. | |
223 | W where-is. Type command name; it prints which keystrokes | |
224 | invoke that command. | |
225 | C-c print Emacs copying permission (General Public License). | |
226 | C-d print Emacs ordering information. | |
227 | C-n print news of recent Emacs changes. | |
228 | C-w print information on absence of warranty for GNU Emacs." | |
229 | (interactive) | |
230 | (message | |
231 | "A B C F I K L M N S T V W C-c C-d C-n C-w. Type C-h again for more help: ") | |
232 | (let ((char (read-char))) | |
233 | (if (or (= char ?\C-h) (= char ??)) | |
234 | (save-window-excursion | |
235 | (switch-to-buffer "*Help*") | |
236 | (delete-other-windows) | |
237 | (erase-buffer) | |
238 | (insert (documentation 'help-for-help)) | |
239 | (goto-char (point-min)) | |
240 | (while (memq char '(?\C-h ?? ?\C-v ?\ ?\177 ?\M-v)) | |
241 | (if (memq char '(?\C-v ?\ )) | |
242 | (scroll-up)) | |
243 | (if (memq char '(?\177 ?\M-v)) | |
244 | (scroll-down)) | |
245 | (message "A B C F I K L M N S T V W C-c C-d C-n C-w%s: " | |
246 | (if (pos-visible-in-window-p (point-max)) | |
247 | "" " or Space to scroll")) | |
248 | (let ((cursor-in-echo-area t)) | |
249 | (setq char (read-char)))))) | |
250 | (let ((defn (cdr (assq (downcase char) (cdr help-map))))) | |
251 | (if defn (call-interactively defn) (ding))))) | |
252 | ||
253 | ||
254 | ;; Return a function which is called by the list containing point. | |
255 | ;; If that gives no function, return a function whose name is around point. | |
256 | ;; If that doesn't give a function, return nil. | |
257 | (defun function-called-at-point () | |
258 | (or (condition-case () | |
259 | (save-excursion | |
260 | (save-restriction | |
261 | (narrow-to-region (max (point-min) (- (point) 1000)) (point-max)) | |
262 | (backward-up-list 1) | |
263 | (forward-char 1) | |
264 | (let (obj) | |
265 | (setq obj (read (current-buffer))) | |
266 | (and (symbolp obj) (fboundp obj) obj)))) | |
267 | (error nil)) | |
268 | (condition-case () | |
269 | (save-excursion | |
270 | (forward-sexp -1) | |
271 | (skip-chars-forward "'") | |
272 | (let ((obj (read (current-buffer)))) | |
273 | (and (symbolp obj) (fboundp obj) obj))) | |
274 | (error nil)))) | |
275 | ||
276 | (defun describe-function (function) | |
277 | "Display the full documentation of FUNCTION (a symbol)." | |
278 | (interactive | |
279 | (let ((fn (function-called-at-point)) | |
280 | (enable-recursive-minibuffers t) | |
281 | val) | |
282 | (setq val (completing-read (if fn | |
283 | (format "Describe function (default %s): " fn) | |
284 | "Describe function: ") | |
285 | obarray 'fboundp t)) | |
286 | (list (if (equal val "") | |
287 | fn (intern val))))) | |
288 | (with-output-to-temp-buffer "*Help*" | |
289 | (prin1 function) | |
290 | (princ ": ") | |
291 | (let* ((def (symbol-function function)) | |
292 | (beg (if (commandp def) "an interactive " "a "))) | |
293 | (princ (cond ((stringp def) "a keyboard macro.") | |
294 | ((subrp def) | |
295 | (concat beg "built-in function.")) | |
296 | ((compiled-function-p def) | |
297 | (concat beg "compiled Lisp function.")) | |
298 | ((symbolp def) | |
299 | (format "alias for `%s'." def)) | |
300 | ((eq (car-safe def) 'lambda) | |
301 | (concat beg "Lisp function.")) | |
302 | ((eq (car-safe def) 'macro) | |
303 | "a Lisp macro.") | |
304 | ((eq (car-safe def) 'mocklisp) | |
305 | "a mocklisp function.") | |
306 | ((eq (car-safe def) 'autoload) | |
307 | (format "%sLisp %s to autoload from `%s'." | |
308 | beg | |
309 | (if (nth 4 def) "macro" "function") | |
310 | (nth 1 def))) | |
311 | (t ""))) | |
312 | (terpri)) | |
313 | (if (documentation function) | |
314 | (princ (documentation function)) | |
315 | (princ "not documented")) | |
316 | (print-help-return-message) | |
317 | ;; Return the text we displayed. | |
318 | (save-excursion (set-buffer standard-output) (buffer-string)))) | |
319 | ||
320 | (defun variable-at-point () | |
321 | (condition-case () | |
322 | (save-excursion | |
323 | (forward-sexp -1) | |
324 | (skip-chars-forward "'") | |
325 | (let ((obj (read (current-buffer)))) | |
326 | (and (symbolp obj) (boundp obj) obj))) | |
327 | (error nil))) | |
328 | ||
329 | (defun describe-variable (variable) | |
330 | "Display the full documentation of VARIABLE (a symbol). | |
331 | Returns the documentation as a string, also." | |
332 | (interactive | |
333 | (let ((v (variable-at-point)) | |
334 | (enable-recursive-minibuffers t) | |
335 | val) | |
336 | (setq val (completing-read (if v | |
337 | (format "Describe variable (default %s): " v) | |
338 | "Describe variable: ") | |
339 | obarray 'boundp t)) | |
340 | (list (if (equal val "") | |
341 | v (intern val))))) | |
342 | (with-output-to-temp-buffer "*Help*" | |
343 | (prin1 variable) | |
344 | (princ "'s value is ") | |
345 | (if (not (boundp variable)) | |
346 | (princ "void.") | |
347 | (prin1 (symbol-value variable))) | |
348 | (terpri) (terpri) | |
349 | (princ "Documentation:") | |
350 | (terpri) | |
351 | (let ((doc (documentation-property variable 'variable-documentation))) | |
352 | (if doc | |
353 | (princ (substitute-command-keys doc)) | |
354 | (princ "not documented as a variable."))) | |
355 | (print-help-return-message) | |
356 | ;; Return the text we displayed. | |
357 | (save-excursion (set-buffer standard-output) (buffer-string)))) | |
358 | ||
359 | (defun command-apropos (string) | |
360 | "Like apropos but lists only symbols that are names of commands | |
361 | \(interactively callable functions). Argument REGEXP is a regular expression | |
362 | that is matched against command symbol names. Returns list of symbols and | |
363 | documentation found." | |
364 | (interactive "sCommand apropos (regexp): ") | |
365 | (let ((message | |
366 | (let ((standard-output (get-buffer-create "*Help*"))) | |
367 | (print-help-return-message 'identity)))) | |
368 | (apropos string 'commandp) | |
369 | (and message (message message)))) | |
370 | ||
371 | (defun locate-library (library &optional nosuffix) | |
372 | "Show the full path name of Emacs library LIBRARY. | |
373 | This command searches the directories in `load-path' like `M-x load-library' | |
374 | to find the file that `M-x load-library RET LIBRARY RET' would load. | |
375 | Optional second arg NOSUFFIX non-nil means don't add suffixes `.elc' or `.el' | |
376 | to the specified name LIBRARY (a la calling `load' instead of `load-library')." | |
377 | (interactive "sLocate library: ") | |
378 | (catch 'answer | |
379 | (mapcar | |
380 | '(lambda (dir) | |
381 | (mapcar | |
382 | '(lambda (suf) | |
383 | (let ((try (expand-file-name (concat library suf) dir))) | |
384 | (and (file-readable-p try) | |
385 | (null (file-directory-p try)) | |
386 | (progn | |
387 | (message "Library is file %s" try) | |
388 | (throw 'answer try))))) | |
389 | (if nosuffix '("") '(".elc" ".el" "")))) | |
390 | load-path) | |
391 | (message "No library %s in search path" library) | |
392 | nil)) | |
1a06eabd ER |
393 | |
394 | ;;; help.el ends here |