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1a06eabd ER |
1 | ;;; help.el --- help commands for Emacs |
2 | ||
b1fe9304 | 3 | ;; Copyright (C) 1985, 1986, 1993 Free Software Foundation, Inc. |
3a801d0c | 4 | |
e5167999 | 5 | ;; Maintainer: FSF |
fd7fa35a | 6 | ;; Keywords: help, internal |
e5167999 | 7 | |
433ae6f6 RS |
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 | ||
d9ecc911 ER |
24 | ;;; Commentary: |
25 | ||
26 | ;; This code implements GNU Emac's on-line help system, the one invoked by | |
27 | ;;`M-x help-for-help'. | |
28 | ||
e5167999 ER |
29 | ;;; Code: |
30 | ||
8aa3a187 RS |
31 | ;; Get the macro make-help-screen when this is compiled, |
32 | ;; or run interpreted, but not when the compiled code is loaded. | |
b1fe9304 | 33 | (eval-when-compile (require 'help-macro)) |
41b8542b | 34 | |
433ae6f6 RS |
35 | (defvar help-map (make-sparse-keymap) |
36 | "Keymap for characters following the Help key.") | |
37 | ||
e17d2fd1 | 38 | (define-key global-map (char-to-string help-char) 'help-command) |
433ae6f6 RS |
39 | (fset 'help-command help-map) |
40 | ||
e17d2fd1 | 41 | (define-key help-map (char-to-string help-char) 'help-for-help) |
433ae6f6 RS |
42 | (define-key help-map "?" 'help-for-help) |
43 | ||
44 | (define-key help-map "\C-c" 'describe-copying) | |
45 | (define-key help-map "\C-d" 'describe-distribution) | |
46 | (define-key help-map "\C-w" 'describe-no-warranty) | |
47 | (define-key help-map "a" 'command-apropos) | |
48 | ||
49 | (define-key help-map "b" 'describe-bindings) | |
50 | ||
51 | (define-key help-map "c" 'describe-key-briefly) | |
52 | (define-key help-map "k" 'describe-key) | |
53 | ||
54 | (define-key help-map "d" 'describe-function) | |
55 | (define-key help-map "f" 'describe-function) | |
56 | ||
57 | (define-key help-map "i" 'info) | |
e5d77022 JB |
58 | (define-key help-map "\C-f" 'Info-goto-emacs-command-node) |
59 | (define-key help-map "\C-k" 'Info-goto-emacs-key-command-node) | |
433ae6f6 RS |
60 | |
61 | (define-key help-map "l" 'view-lossage) | |
62 | ||
63 | (define-key help-map "m" 'describe-mode) | |
64 | ||
65 | (define-key help-map "\C-n" 'view-emacs-news) | |
66 | (define-key help-map "n" 'view-emacs-news) | |
67 | ||
06b98c51 | 68 | (define-key help-map "p" 'finder-by-keyword) |
abe85b1b | 69 | (autoload 'finder-by-keyword "finder") |
06b98c51 | 70 | |
433ae6f6 RS |
71 | (define-key help-map "s" 'describe-syntax) |
72 | ||
73 | (define-key help-map "t" 'help-with-tutorial) | |
74 | ||
75 | (define-key help-map "w" 'where-is) | |
76 | ||
77 | (define-key help-map "v" 'describe-variable) | |
78 | ||
79 | (defun help-with-tutorial () | |
80 | "Select the Emacs learn-by-doing tutorial." | |
81 | (interactive) | |
82 | (let ((file (expand-file-name "~/TUTORIAL"))) | |
83 | (delete-other-windows) | |
84 | (if (get-file-buffer file) | |
85 | (switch-to-buffer (get-file-buffer file)) | |
86 | (switch-to-buffer (create-file-buffer file)) | |
87 | (setq buffer-file-name file) | |
88 | (setq default-directory (expand-file-name "~/")) | |
79058860 | 89 | (setq buffer-auto-save-file-name nil) |
1e6dacf6 | 90 | (insert-file-contents (expand-file-name "TUTORIAL" data-directory)) |
433ae6f6 RS |
91 | (goto-char (point-min)) |
92 | (search-forward "\n<<") | |
93 | (beginning-of-line) | |
94 | (delete-region (point) (progn (end-of-line) (point))) | |
95 | (newline (- (window-height (selected-window)) | |
96 | (count-lines (point-min) (point)) | |
97 | 6)) | |
98 | (goto-char (point-min)) | |
99 | (set-buffer-modified-p nil)))) | |
100 | ||
101 | (defun describe-key-briefly (key) | |
102 | "Print the name of the function KEY invokes. KEY is a string." | |
103 | (interactive "kDescribe key briefly: ") | |
5f296b78 RS |
104 | ;; If this key seq ends with a down event, discard the |
105 | ;; following click or drag event. Otherwise that would | |
106 | ;; erase the message. | |
107 | (let ((type (aref key (1- (length key))))) | |
108 | (if (listp type) (setq type (car type))) | |
109 | (and (symbolp type) | |
110 | (memq 'down (event-modifiers type)) | |
111 | (setq foo (read-event)))) | |
433ae6f6 RS |
112 | (let ((defn (key-binding key))) |
113 | (if (or (null defn) (integerp defn)) | |
114 | (message "%s is undefined" (key-description key)) | |
115 | (message "%s runs the command %s" | |
116 | (key-description key) | |
117 | (if (symbolp defn) defn (prin1-to-string defn)))))) | |
118 | ||
119 | (defun print-help-return-message (&optional function) | |
120 | "Display or return message saying how to restore windows after help command. | |
121 | Computes a message and applies the optional argument FUNCTION to it. | |
122 | If FUNCTION is nil, applies `message' to it, thus printing it." | |
123 | (and (not (get-buffer-window standard-output)) | |
124 | (funcall (or function 'message) | |
125 | (concat | |
126 | (substitute-command-keys | |
127 | (if (one-window-p t) | |
128 | (if pop-up-windows | |
129 | "Type \\[delete-other-windows] to remove help window." | |
130 | "Type \\[switch-to-buffer] RET to remove help window.") | |
131 | "Type \\[switch-to-buffer-other-window] RET to restore the other window.")) | |
132 | (substitute-command-keys | |
133 | " \\[scroll-other-window] to scroll the help."))))) | |
134 | ||
135 | (defun describe-key (key) | |
136 | "Display documentation of the function invoked by KEY. KEY is a string." | |
137 | (interactive "kDescribe key: ") | |
5f296b78 RS |
138 | ;; If this key seq ends with a down event, discard the |
139 | ;; following click or drag event. Otherwise that would | |
140 | ;; erase the message. | |
141 | (let ((type (aref key (1- (length key))))) | |
142 | (if (listp type) (setq type (car type))) | |
143 | (and (symbolp type) | |
144 | (memq 'down (event-modifiers type)) | |
145 | (read-event))) | |
433ae6f6 RS |
146 | (let ((defn (key-binding key))) |
147 | (if (or (null defn) (integerp defn)) | |
148 | (message "%s is undefined" (key-description key)) | |
149 | (with-output-to-temp-buffer "*Help*" | |
150 | (prin1 defn) | |
151 | (princ ":\n") | |
152 | (if (documentation defn) | |
153 | (princ (documentation defn)) | |
154 | (princ "not documented")) | |
155 | (print-help-return-message))))) | |
156 | ||
157 | (defun describe-mode (&optional minor) | |
158 | "Display documentation of current major mode. | |
159 | If optional MINOR is non-nil (or prefix argument is given if interactive), | |
160 | display documentation of active minor modes as well. | |
161 | For this to work correctly for a minor mode, the mode's indicator variable | |
61c6b658 | 162 | \(listed in `minor-mode-alist') must also be a function whose documentation |
433ae6f6 RS |
163 | describes the minor mode." |
164 | (interactive) | |
165 | (with-output-to-temp-buffer "*Help*" | |
166 | (princ mode-name) | |
167 | (princ " Mode:\n") | |
168 | (princ (documentation major-mode)) | |
169 | (let ((minor-modes minor-mode-alist) | |
170 | (locals (buffer-local-variables))) | |
171 | (while minor-modes | |
172 | (let* ((minor-mode (car (car minor-modes))) | |
173 | (indicator (car (cdr (car minor-modes)))) | |
174 | (local-binding (assq minor-mode locals))) | |
175 | ;; Document a minor mode if it is listed in minor-mode-alist, | |
176 | ;; bound locally in this buffer, non-nil, and has a function | |
177 | ;; definition. | |
178 | (if (and local-binding | |
179 | (cdr local-binding) | |
180 | (fboundp minor-mode)) | |
181 | (progn | |
182 | (princ (format "\n\n\n%s minor mode (indicator%s):\n" | |
183 | minor-mode indicator)) | |
184 | (princ (documentation minor-mode))))) | |
185 | (setq minor-modes (cdr minor-modes)))) | |
186 | (print-help-return-message))) | |
187 | ||
188 | ;; So keyboard macro definitions are documented correctly | |
189 | (fset 'defining-kbd-macro (symbol-function 'start-kbd-macro)) | |
190 | ||
191 | (defun describe-distribution () | |
192 | "Display info on how to obtain the latest version of GNU Emacs." | |
193 | (interactive) | |
194 | (find-file-read-only | |
1e6dacf6 | 195 | (expand-file-name "DISTRIB" data-directory))) |
433ae6f6 RS |
196 | |
197 | (defun describe-copying () | |
198 | "Display info on how you may redistribute copies of GNU Emacs." | |
199 | (interactive) | |
200 | (find-file-read-only | |
1e6dacf6 | 201 | (expand-file-name "COPYING" data-directory)) |
433ae6f6 RS |
202 | (goto-char (point-min))) |
203 | ||
204 | (defun describe-no-warranty () | |
205 | "Display info on all the kinds of warranty Emacs does NOT have." | |
206 | (interactive) | |
207 | (describe-copying) | |
208 | (let (case-fold-search) | |
209 | (search-forward "NO WARRANTY") | |
210 | (recenter 0))) | |
211 | ||
61c6b658 | 212 | (defun describe-prefix-bindings () |
c7cba9cb RS |
213 | "Describe the bindings of the prefix used to reach this command. |
214 | The prefix described consists of all but the last event | |
215 | of the key sequence that ran this command." | |
61c6b658 RS |
216 | (interactive) |
217 | (let* ((key (this-command-keys)) | |
218 | (prefix (make-vector (1- (length key)) nil)) | |
219 | i) | |
220 | (setq i 0) | |
221 | (while (< i (length prefix)) | |
222 | (aset prefix i (aref key i)) | |
223 | (setq i (1+ i))) | |
224 | (describe-bindings prefix))) | |
c7cba9cb RS |
225 | ;; Make C-h after a prefix, when not specifically bound, |
226 | ;; run describe-prefix-bindings. | |
61c6b658 RS |
227 | (setq prefix-help-command 'describe-prefix-bindings) |
228 | ||
433ae6f6 RS |
229 | (defun view-emacs-news () |
230 | "Display info on recent changes to Emacs." | |
231 | (interactive) | |
1e6dacf6 | 232 | (find-file-read-only (expand-file-name "NEWS" data-directory))) |
433ae6f6 RS |
233 | |
234 | (defun view-lossage () | |
235 | "Display last 100 input keystrokes." | |
236 | (interactive) | |
237 | (with-output-to-temp-buffer "*Help*" | |
238 | (princ (key-description (recent-keys))) | |
239 | (save-excursion | |
240 | (set-buffer standard-output) | |
241 | (goto-char (point-min)) | |
242 | (while (progn (move-to-column 50) (not (eobp))) | |
243 | (search-forward " " nil t) | |
244 | (insert "\n"))) | |
245 | (print-help-return-message))) | |
246 | ||
41b8542b | 247 | (make-help-screen help-for-help |
af6a9de9 | 248 | "a b c f i k l m n p s t v w C-c C-d C-n C-w. Type \\[help-for-help] again for more help: " |
c3aef019 | 249 | "You have typed \\[help-for-help], the help character. Type a Help option: |
433ae6f6 | 250 | |
af6a9de9 | 251 | a command-apropos. Give a substring, and see a list of commands |
433ae6f6 RS |
252 | (functions interactively callable) that contain |
253 | that substring. See also the apropos command. | |
af6a9de9 RS |
254 | b describe-bindings. Display table of all key bindings. |
255 | c describe-key-briefly. Type a command key sequence; | |
433ae6f6 | 256 | it prints the function name that sequence runs. |
af6a9de9 RS |
257 | f describe-function. Type a function name and get documentation of it. |
258 | i info. The info documentation reader. | |
259 | k describe-key. Type a command key sequence; | |
433ae6f6 | 260 | it displays the full documentation. |
af6a9de9 RS |
261 | l view-lossage. Shows last 100 characters you typed. |
262 | m describe-mode. Print documentation of current major mode, | |
433ae6f6 | 263 | which describes the commands peculiar to it. |
af6a9de9 RS |
264 | n view-emacs-news. Shows emacs news file. |
265 | p finder-by-keyword. Find packages matching a given topic keyword. | |
266 | s describe-syntax. Display contents of syntax table, plus explanations | |
267 | t help-with-tutorial. Select the Emacs learn-by-doing tutorial. | |
268 | v describe-variable. Type name of a variable; | |
433ae6f6 | 269 | it displays the variable's documentation and value. |
af6a9de9 | 270 | w where-is. Type command name; it prints which keystrokes |
433ae6f6 RS |
271 | invoke that command. |
272 | C-c print Emacs copying permission (General Public License). | |
273 | C-d print Emacs ordering information. | |
274 | C-n print news of recent Emacs changes. | |
275 | C-w print information on absence of warranty for GNU Emacs." | |
41b8542b | 276 | help-map) |
433ae6f6 RS |
277 | |
278 | ;; Return a function which is called by the list containing point. | |
279 | ;; If that gives no function, return a function whose name is around point. | |
280 | ;; If that doesn't give a function, return nil. | |
281 | (defun function-called-at-point () | |
282 | (or (condition-case () | |
283 | (save-excursion | |
284 | (save-restriction | |
285 | (narrow-to-region (max (point-min) (- (point) 1000)) (point-max)) | |
286 | (backward-up-list 1) | |
287 | (forward-char 1) | |
288 | (let (obj) | |
289 | (setq obj (read (current-buffer))) | |
290 | (and (symbolp obj) (fboundp obj) obj)))) | |
291 | (error nil)) | |
292 | (condition-case () | |
293 | (save-excursion | |
294 | (forward-sexp -1) | |
295 | (skip-chars-forward "'") | |
296 | (let ((obj (read (current-buffer)))) | |
297 | (and (symbolp obj) (fboundp obj) obj))) | |
298 | (error nil)))) | |
299 | ||
300 | (defun describe-function (function) | |
301 | "Display the full documentation of FUNCTION (a symbol)." | |
302 | (interactive | |
303 | (let ((fn (function-called-at-point)) | |
304 | (enable-recursive-minibuffers t) | |
305 | val) | |
306 | (setq val (completing-read (if fn | |
307 | (format "Describe function (default %s): " fn) | |
308 | "Describe function: ") | |
309 | obarray 'fboundp t)) | |
310 | (list (if (equal val "") | |
311 | fn (intern val))))) | |
312 | (with-output-to-temp-buffer "*Help*" | |
313 | (prin1 function) | |
314 | (princ ": ") | |
315 | (let* ((def (symbol-function function)) | |
316 | (beg (if (commandp def) "an interactive " "a "))) | |
7f26b180 RM |
317 | (princ (cond ((or (stringp def) |
318 | (vectorp def)) | |
319 | "a keyboard macro.") | |
433ae6f6 RS |
320 | ((subrp def) |
321 | (concat beg "built-in function.")) | |
dbc4e1c1 | 322 | ((byte-code-function-p def) |
433ae6f6 RS |
323 | (concat beg "compiled Lisp function.")) |
324 | ((symbolp def) | |
325 | (format "alias for `%s'." def)) | |
326 | ((eq (car-safe def) 'lambda) | |
327 | (concat beg "Lisp function.")) | |
328 | ((eq (car-safe def) 'macro) | |
329 | "a Lisp macro.") | |
330 | ((eq (car-safe def) 'mocklisp) | |
331 | "a mocklisp function.") | |
332 | ((eq (car-safe def) 'autoload) | |
762435dd RS |
333 | (format "%s autoloaded Lisp %s." |
334 | (if (commandp def) "an interactive" "an") | |
433ae6f6 | 335 | (if (nth 4 def) "macro" "function") |
ab67260b RS |
336 | ;;; Including the file name made this line too long. |
337 | ;;; (nth 1 def) | |
338 | )) | |
433ae6f6 | 339 | (t ""))) |
4591cb90 | 340 | (terpri) |
7f26b180 RM |
341 | (let ((arglist (cond ((byte-code-function-p def) |
342 | (car (append def nil))) | |
343 | ((eq (car-safe def) 'lambda) | |
344 | (nth 1 def)) | |
345 | (t t)))) | |
346 | (if (listp arglist) | |
347 | (progn | |
348 | (princ (cons function | |
349 | (mapcar (lambda (arg) | |
350 | (if (memq arg '(&optional &rest)) | |
351 | arg | |
352 | (intern (upcase (symbol-name arg))))) | |
353 | arglist))) | |
354 | (terpri)))) | |
4591cb90 | 355 | (if (documentation function) |
cdd672cc RS |
356 | (progn (terpri) |
357 | (princ (documentation function))) | |
4591cb90 | 358 | (princ "not documented")) |
7f26b180 | 359 | ) |
433ae6f6 RS |
360 | (print-help-return-message) |
361 | ;; Return the text we displayed. | |
362 | (save-excursion (set-buffer standard-output) (buffer-string)))) | |
363 | ||
364 | (defun variable-at-point () | |
365 | (condition-case () | |
366 | (save-excursion | |
367 | (forward-sexp -1) | |
368 | (skip-chars-forward "'") | |
369 | (let ((obj (read (current-buffer)))) | |
370 | (and (symbolp obj) (boundp obj) obj))) | |
371 | (error nil))) | |
372 | ||
373 | (defun describe-variable (variable) | |
374 | "Display the full documentation of VARIABLE (a symbol). | |
375 | Returns the documentation as a string, also." | |
376 | (interactive | |
377 | (let ((v (variable-at-point)) | |
378 | (enable-recursive-minibuffers t) | |
379 | val) | |
380 | (setq val (completing-read (if v | |
381 | (format "Describe variable (default %s): " v) | |
382 | "Describe variable: ") | |
383 | obarray 'boundp t)) | |
384 | (list (if (equal val "") | |
385 | v (intern val))))) | |
386 | (with-output-to-temp-buffer "*Help*" | |
387 | (prin1 variable) | |
388 | (princ "'s value is ") | |
389 | (if (not (boundp variable)) | |
390 | (princ "void.") | |
391 | (prin1 (symbol-value variable))) | |
392 | (terpri) (terpri) | |
393 | (princ "Documentation:") | |
394 | (terpri) | |
395 | (let ((doc (documentation-property variable 'variable-documentation))) | |
396 | (if doc | |
397 | (princ (substitute-command-keys doc)) | |
398 | (princ "not documented as a variable."))) | |
399 | (print-help-return-message) | |
400 | ;; Return the text we displayed. | |
401 | (save-excursion (set-buffer standard-output) (buffer-string)))) | |
402 | ||
403 | (defun command-apropos (string) | |
404 | "Like apropos but lists only symbols that are names of commands | |
405 | \(interactively callable functions). Argument REGEXP is a regular expression | |
406 | that is matched against command symbol names. Returns list of symbols and | |
407 | documentation found." | |
408 | (interactive "sCommand apropos (regexp): ") | |
409 | (let ((message | |
410 | (let ((standard-output (get-buffer-create "*Help*"))) | |
411 | (print-help-return-message 'identity)))) | |
78e3ef3c RS |
412 | (if (apropos string t 'commandp) |
413 | (and message (message message))))) | |
433ae6f6 RS |
414 | |
415 | (defun locate-library (library &optional nosuffix) | |
416 | "Show the full path name of Emacs library LIBRARY. | |
417 | This command searches the directories in `load-path' like `M-x load-library' | |
418 | to find the file that `M-x load-library RET LIBRARY RET' would load. | |
419 | Optional second arg NOSUFFIX non-nil means don't add suffixes `.elc' or `.el' | |
420 | to the specified name LIBRARY (a la calling `load' instead of `load-library')." | |
421 | (interactive "sLocate library: ") | |
422 | (catch 'answer | |
423 | (mapcar | |
424 | '(lambda (dir) | |
425 | (mapcar | |
426 | '(lambda (suf) | |
427 | (let ((try (expand-file-name (concat library suf) dir))) | |
428 | (and (file-readable-p try) | |
429 | (null (file-directory-p try)) | |
430 | (progn | |
431 | (message "Library is file %s" try) | |
432 | (throw 'answer try))))) | |
433 | (if nosuffix '("") '(".elc" ".el" "")))) | |
434 | load-path) | |
435 | (message "No library %s in search path" library) | |
436 | nil)) | |
1a06eabd ER |
437 | |
438 | ;;; help.el ends here |