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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) | |
76766f2d | 47 | (define-key help-map "\C-p" 'describe-project) |
433ae6f6 RS |
48 | (define-key help-map "a" 'command-apropos) |
49 | ||
50 | (define-key help-map "b" 'describe-bindings) | |
51 | ||
52 | (define-key help-map "c" 'describe-key-briefly) | |
53 | (define-key help-map "k" 'describe-key) | |
54 | ||
55 | (define-key help-map "d" 'describe-function) | |
56 | (define-key help-map "f" 'describe-function) | |
57 | ||
58 | (define-key help-map "i" 'info) | |
e5d77022 JB |
59 | (define-key help-map "\C-f" 'Info-goto-emacs-command-node) |
60 | (define-key help-map "\C-k" 'Info-goto-emacs-key-command-node) | |
433ae6f6 RS |
61 | |
62 | (define-key help-map "l" 'view-lossage) | |
63 | ||
64 | (define-key help-map "m" 'describe-mode) | |
65 | ||
66 | (define-key help-map "\C-n" 'view-emacs-news) | |
67 | (define-key help-map "n" 'view-emacs-news) | |
68 | ||
06b98c51 | 69 | (define-key help-map "p" 'finder-by-keyword) |
abe85b1b | 70 | (autoload 'finder-by-keyword "finder") |
06b98c51 | 71 | |
433ae6f6 RS |
72 | (define-key help-map "s" 'describe-syntax) |
73 | ||
74 | (define-key help-map "t" 'help-with-tutorial) | |
75 | ||
76 | (define-key help-map "w" 'where-is) | |
77 | ||
78 | (define-key help-map "v" 'describe-variable) | |
79 | ||
80 | (defun help-with-tutorial () | |
81 | "Select the Emacs learn-by-doing tutorial." | |
82 | (interactive) | |
83 | (let ((file (expand-file-name "~/TUTORIAL"))) | |
84 | (delete-other-windows) | |
85 | (if (get-file-buffer file) | |
86 | (switch-to-buffer (get-file-buffer file)) | |
87 | (switch-to-buffer (create-file-buffer file)) | |
88 | (setq buffer-file-name file) | |
89 | (setq default-directory (expand-file-name "~/")) | |
79058860 | 90 | (setq buffer-auto-save-file-name nil) |
1e6dacf6 | 91 | (insert-file-contents (expand-file-name "TUTORIAL" data-directory)) |
433ae6f6 RS |
92 | (goto-char (point-min)) |
93 | (search-forward "\n<<") | |
94 | (beginning-of-line) | |
95 | (delete-region (point) (progn (end-of-line) (point))) | |
857a1de6 | 96 | (let ((n (- (window-height (selected-window)) |
433ae6f6 | 97 | (count-lines (point-min) (point)) |
857a1de6 KH |
98 | 6))) |
99 | (if (< n 20) | |
100 | (newline n) | |
101 | ;; Some people get confused by the large gap. | |
102 | (newline (/ n 2)) | |
103 | (insert "[Middle of page left blank for didactic purposes. " | |
104 | "Text continues below]") | |
105 | (newline (- n (/ n 2))))) | |
433ae6f6 RS |
106 | (goto-char (point-min)) |
107 | (set-buffer-modified-p nil)))) | |
108 | ||
109 | (defun describe-key-briefly (key) | |
110 | "Print the name of the function KEY invokes. KEY is a string." | |
111 | (interactive "kDescribe key briefly: ") | |
5f296b78 RS |
112 | ;; If this key seq ends with a down event, discard the |
113 | ;; following click or drag event. Otherwise that would | |
114 | ;; erase the message. | |
115 | (let ((type (aref key (1- (length key))))) | |
116 | (if (listp type) (setq type (car type))) | |
117 | (and (symbolp type) | |
118 | (memq 'down (event-modifiers type)) | |
fca4b775 | 119 | (read-event))) |
433ae6f6 RS |
120 | (let ((defn (key-binding key))) |
121 | (if (or (null defn) (integerp defn)) | |
122 | (message "%s is undefined" (key-description key)) | |
123 | (message "%s runs the command %s" | |
124 | (key-description key) | |
125 | (if (symbolp defn) defn (prin1-to-string defn)))))) | |
126 | ||
127 | (defun print-help-return-message (&optional function) | |
128 | "Display or return message saying how to restore windows after help command. | |
129 | Computes a message and applies the optional argument FUNCTION to it. | |
130 | If FUNCTION is nil, applies `message' to it, thus printing it." | |
131 | (and (not (get-buffer-window standard-output)) | |
132 | (funcall (or function 'message) | |
133 | (concat | |
134 | (substitute-command-keys | |
135 | (if (one-window-p t) | |
136 | (if pop-up-windows | |
137 | "Type \\[delete-other-windows] to remove help window." | |
138 | "Type \\[switch-to-buffer] RET to remove help window.") | |
139 | "Type \\[switch-to-buffer-other-window] RET to restore the other window.")) | |
140 | (substitute-command-keys | |
141 | " \\[scroll-other-window] to scroll the help."))))) | |
142 | ||
143 | (defun describe-key (key) | |
144 | "Display documentation of the function invoked by KEY. KEY is a string." | |
145 | (interactive "kDescribe key: ") | |
5f296b78 RS |
146 | ;; If this key seq ends with a down event, discard the |
147 | ;; following click or drag event. Otherwise that would | |
148 | ;; erase the message. | |
149 | (let ((type (aref key (1- (length key))))) | |
150 | (if (listp type) (setq type (car type))) | |
151 | (and (symbolp type) | |
152 | (memq 'down (event-modifiers type)) | |
153 | (read-event))) | |
433ae6f6 RS |
154 | (let ((defn (key-binding key))) |
155 | (if (or (null defn) (integerp defn)) | |
156 | (message "%s is undefined" (key-description key)) | |
157 | (with-output-to-temp-buffer "*Help*" | |
158 | (prin1 defn) | |
159 | (princ ":\n") | |
160 | (if (documentation defn) | |
161 | (princ (documentation defn)) | |
162 | (princ "not documented")) | |
163 | (print-help-return-message))))) | |
164 | ||
165 | (defun describe-mode (&optional minor) | |
166 | "Display documentation of current major mode. | |
167 | If optional MINOR is non-nil (or prefix argument is given if interactive), | |
168 | display documentation of active minor modes as well. | |
169 | For this to work correctly for a minor mode, the mode's indicator variable | |
61c6b658 | 170 | \(listed in `minor-mode-alist') must also be a function whose documentation |
433ae6f6 RS |
171 | describes the minor mode." |
172 | (interactive) | |
173 | (with-output-to-temp-buffer "*Help*" | |
174 | (princ mode-name) | |
175 | (princ " Mode:\n") | |
176 | (princ (documentation major-mode)) | |
177 | (let ((minor-modes minor-mode-alist) | |
178 | (locals (buffer-local-variables))) | |
179 | (while minor-modes | |
180 | (let* ((minor-mode (car (car minor-modes))) | |
181 | (indicator (car (cdr (car minor-modes)))) | |
182 | (local-binding (assq minor-mode locals))) | |
183 | ;; Document a minor mode if it is listed in minor-mode-alist, | |
184 | ;; bound locally in this buffer, non-nil, and has a function | |
185 | ;; definition. | |
186 | (if (and local-binding | |
187 | (cdr local-binding) | |
188 | (fboundp minor-mode)) | |
189 | (progn | |
190 | (princ (format "\n\n\n%s minor mode (indicator%s):\n" | |
191 | minor-mode indicator)) | |
192 | (princ (documentation minor-mode))))) | |
193 | (setq minor-modes (cdr minor-modes)))) | |
194 | (print-help-return-message))) | |
195 | ||
196 | ;; So keyboard macro definitions are documented correctly | |
197 | (fset 'defining-kbd-macro (symbol-function 'start-kbd-macro)) | |
198 | ||
199 | (defun describe-distribution () | |
200 | "Display info on how to obtain the latest version of GNU Emacs." | |
201 | (interactive) | |
202 | (find-file-read-only | |
1e6dacf6 | 203 | (expand-file-name "DISTRIB" data-directory))) |
433ae6f6 RS |
204 | |
205 | (defun describe-copying () | |
206 | "Display info on how you may redistribute copies of GNU Emacs." | |
207 | (interactive) | |
208 | (find-file-read-only | |
1e6dacf6 | 209 | (expand-file-name "COPYING" data-directory)) |
433ae6f6 RS |
210 | (goto-char (point-min))) |
211 | ||
76766f2d RS |
212 | (defun describe-project () |
213 | "Display info on the GNU project." | |
214 | (interactive) | |
215 | (find-file-read-only | |
216 | (expand-file-name "GNU" data-directory)) | |
217 | (goto-char (point-min))) | |
218 | ||
433ae6f6 RS |
219 | (defun describe-no-warranty () |
220 | "Display info on all the kinds of warranty Emacs does NOT have." | |
221 | (interactive) | |
222 | (describe-copying) | |
223 | (let (case-fold-search) | |
224 | (search-forward "NO WARRANTY") | |
225 | (recenter 0))) | |
226 | ||
61c6b658 | 227 | (defun describe-prefix-bindings () |
c7cba9cb RS |
228 | "Describe the bindings of the prefix used to reach this command. |
229 | The prefix described consists of all but the last event | |
230 | of the key sequence that ran this command." | |
61c6b658 RS |
231 | (interactive) |
232 | (let* ((key (this-command-keys)) | |
233 | (prefix (make-vector (1- (length key)) nil)) | |
234 | i) | |
235 | (setq i 0) | |
236 | (while (< i (length prefix)) | |
237 | (aset prefix i (aref key i)) | |
238 | (setq i (1+ i))) | |
239 | (describe-bindings prefix))) | |
c7cba9cb RS |
240 | ;; Make C-h after a prefix, when not specifically bound, |
241 | ;; run describe-prefix-bindings. | |
61c6b658 RS |
242 | (setq prefix-help-command 'describe-prefix-bindings) |
243 | ||
433ae6f6 RS |
244 | (defun view-emacs-news () |
245 | "Display info on recent changes to Emacs." | |
246 | (interactive) | |
1e6dacf6 | 247 | (find-file-read-only (expand-file-name "NEWS" data-directory))) |
433ae6f6 RS |
248 | |
249 | (defun view-lossage () | |
250 | "Display last 100 input keystrokes." | |
251 | (interactive) | |
252 | (with-output-to-temp-buffer "*Help*" | |
253 | (princ (key-description (recent-keys))) | |
254 | (save-excursion | |
255 | (set-buffer standard-output) | |
256 | (goto-char (point-min)) | |
257 | (while (progn (move-to-column 50) (not (eobp))) | |
258 | (search-forward " " nil t) | |
259 | (insert "\n"))) | |
260 | (print-help-return-message))) | |
261 | ||
41b8542b | 262 | (make-help-screen help-for-help |
224d56a3 | 263 | "a b c f C-f i k C-k l m n p s t v w C-c C-d C-n C-w, or ? for more help:" |
76766f2d | 264 | "You have typed \\[help-command], the help character. Type a Help option: |
a9d3e917 | 265 | \(Use \\<help-map>\\[scroll-up] or \\[scroll-down] to scroll through this text.) |
433ae6f6 | 266 | |
21ee8c42 RM |
267 | a command-apropos. Give a substring, and see a list of commands |
268 | (functions interactively callable) that contain | |
269 | that substring. See also the apropos command. | |
af6a9de9 RS |
270 | b describe-bindings. Display table of all key bindings. |
271 | c describe-key-briefly. Type a command key sequence; | |
21ee8c42 | 272 | it prints the function name that sequence runs. |
af6a9de9 | 273 | f describe-function. Type a function name and get documentation of it. |
21ee8c42 RM |
274 | C-f Info-goto-emacs-command-node. Type a function name; |
275 | it takes you to the Info node for that command. | |
af6a9de9 RS |
276 | i info. The info documentation reader. |
277 | k describe-key. Type a command key sequence; | |
21ee8c42 RM |
278 | it displays the full documentation. |
279 | C-k Info-goto-emacs-key-command-node. Type a command key sequence; | |
280 | it takes you to the Info node for the command bound to that key. | |
af6a9de9 RS |
281 | l view-lossage. Shows last 100 characters you typed. |
282 | m describe-mode. Print documentation of current major mode, | |
21ee8c42 | 283 | which describes the commands peculiar to it. |
af6a9de9 RS |
284 | n view-emacs-news. Shows emacs news file. |
285 | p finder-by-keyword. Find packages matching a given topic keyword. | |
286 | s describe-syntax. Display contents of syntax table, plus explanations | |
287 | t help-with-tutorial. Select the Emacs learn-by-doing tutorial. | |
288 | v describe-variable. Type name of a variable; | |
21ee8c42 | 289 | it displays the variable's documentation and value. |
af6a9de9 | 290 | w where-is. Type command name; it prints which keystrokes |
21ee8c42 | 291 | invoke that command. |
433ae6f6 RS |
292 | C-c print Emacs copying permission (General Public License). |
293 | C-d print Emacs ordering information. | |
294 | C-n print news of recent Emacs changes. | |
76766f2d | 295 | C-p print information about the GNU project. |
433ae6f6 | 296 | C-w print information on absence of warranty for GNU Emacs." |
41b8542b | 297 | help-map) |
433ae6f6 RS |
298 | |
299 | ;; Return a function which is called by the list containing point. | |
300 | ;; If that gives no function, return a function whose name is around point. | |
301 | ;; If that doesn't give a function, return nil. | |
302 | (defun function-called-at-point () | |
303 | (or (condition-case () | |
304 | (save-excursion | |
305 | (save-restriction | |
306 | (narrow-to-region (max (point-min) (- (point) 1000)) (point-max)) | |
307 | (backward-up-list 1) | |
308 | (forward-char 1) | |
309 | (let (obj) | |
310 | (setq obj (read (current-buffer))) | |
311 | (and (symbolp obj) (fboundp obj) obj)))) | |
312 | (error nil)) | |
313 | (condition-case () | |
314 | (save-excursion | |
315 | (forward-sexp -1) | |
316 | (skip-chars-forward "'") | |
317 | (let ((obj (read (current-buffer)))) | |
318 | (and (symbolp obj) (fboundp obj) obj))) | |
319 | (error nil)))) | |
320 | ||
321 | (defun describe-function (function) | |
322 | "Display the full documentation of FUNCTION (a symbol)." | |
323 | (interactive | |
324 | (let ((fn (function-called-at-point)) | |
325 | (enable-recursive-minibuffers t) | |
326 | val) | |
327 | (setq val (completing-read (if fn | |
328 | (format "Describe function (default %s): " fn) | |
329 | "Describe function: ") | |
330 | obarray 'fboundp t)) | |
331 | (list (if (equal val "") | |
332 | fn (intern val))))) | |
333 | (with-output-to-temp-buffer "*Help*" | |
334 | (prin1 function) | |
335 | (princ ": ") | |
336 | (let* ((def (symbol-function function)) | |
337 | (beg (if (commandp def) "an interactive " "a "))) | |
7f26b180 RM |
338 | (princ (cond ((or (stringp def) |
339 | (vectorp def)) | |
340 | "a keyboard macro.") | |
433ae6f6 RS |
341 | ((subrp def) |
342 | (concat beg "built-in function.")) | |
dbc4e1c1 | 343 | ((byte-code-function-p def) |
433ae6f6 RS |
344 | (concat beg "compiled Lisp function.")) |
345 | ((symbolp def) | |
346 | (format "alias for `%s'." def)) | |
347 | ((eq (car-safe def) 'lambda) | |
348 | (concat beg "Lisp function.")) | |
349 | ((eq (car-safe def) 'macro) | |
350 | "a Lisp macro.") | |
351 | ((eq (car-safe def) 'mocklisp) | |
352 | "a mocklisp function.") | |
353 | ((eq (car-safe def) 'autoload) | |
762435dd RS |
354 | (format "%s autoloaded Lisp %s." |
355 | (if (commandp def) "an interactive" "an") | |
433ae6f6 | 356 | (if (nth 4 def) "macro" "function") |
ab67260b RS |
357 | ;;; Including the file name made this line too long. |
358 | ;;; (nth 1 def) | |
359 | )) | |
433ae6f6 | 360 | (t ""))) |
4591cb90 | 361 | (terpri) |
7f26b180 RM |
362 | (let ((arglist (cond ((byte-code-function-p def) |
363 | (car (append def nil))) | |
364 | ((eq (car-safe def) 'lambda) | |
365 | (nth 1 def)) | |
366 | (t t)))) | |
367 | (if (listp arglist) | |
368 | (progn | |
369 | (princ (cons function | |
370 | (mapcar (lambda (arg) | |
371 | (if (memq arg '(&optional &rest)) | |
372 | arg | |
373 | (intern (upcase (symbol-name arg))))) | |
374 | arglist))) | |
375 | (terpri)))) | |
4591cb90 | 376 | (if (documentation function) |
cdd672cc RS |
377 | (progn (terpri) |
378 | (princ (documentation function))) | |
4591cb90 | 379 | (princ "not documented")) |
7f26b180 | 380 | ) |
433ae6f6 RS |
381 | (print-help-return-message) |
382 | ;; Return the text we displayed. | |
383 | (save-excursion (set-buffer standard-output) (buffer-string)))) | |
384 | ||
385 | (defun variable-at-point () | |
386 | (condition-case () | |
387 | (save-excursion | |
388 | (forward-sexp -1) | |
389 | (skip-chars-forward "'") | |
390 | (let ((obj (read (current-buffer)))) | |
391 | (and (symbolp obj) (boundp obj) obj))) | |
392 | (error nil))) | |
393 | ||
394 | (defun describe-variable (variable) | |
395 | "Display the full documentation of VARIABLE (a symbol). | |
396 | Returns the documentation as a string, also." | |
397 | (interactive | |
398 | (let ((v (variable-at-point)) | |
399 | (enable-recursive-minibuffers t) | |
400 | val) | |
401 | (setq val (completing-read (if v | |
402 | (format "Describe variable (default %s): " v) | |
403 | "Describe variable: ") | |
404 | obarray 'boundp t)) | |
405 | (list (if (equal val "") | |
406 | v (intern val))))) | |
407 | (with-output-to-temp-buffer "*Help*" | |
408 | (prin1 variable) | |
409 | (princ "'s value is ") | |
410 | (if (not (boundp variable)) | |
411 | (princ "void.") | |
412 | (prin1 (symbol-value variable))) | |
413 | (terpri) (terpri) | |
414 | (princ "Documentation:") | |
415 | (terpri) | |
416 | (let ((doc (documentation-property variable 'variable-documentation))) | |
417 | (if doc | |
418 | (princ (substitute-command-keys doc)) | |
419 | (princ "not documented as a variable."))) | |
420 | (print-help-return-message) | |
421 | ;; Return the text we displayed. | |
422 | (save-excursion (set-buffer standard-output) (buffer-string)))) | |
423 | ||
424 | (defun command-apropos (string) | |
425 | "Like apropos but lists only symbols that are names of commands | |
426 | \(interactively callable functions). Argument REGEXP is a regular expression | |
427 | that is matched against command symbol names. Returns list of symbols and | |
428 | documentation found." | |
429 | (interactive "sCommand apropos (regexp): ") | |
430 | (let ((message | |
431 | (let ((standard-output (get-buffer-create "*Help*"))) | |
432 | (print-help-return-message 'identity)))) | |
78e3ef3c RS |
433 | (if (apropos string t 'commandp) |
434 | (and message (message message))))) | |
433ae6f6 RS |
435 | |
436 | (defun locate-library (library &optional nosuffix) | |
437 | "Show the full path name of Emacs library LIBRARY. | |
438 | This command searches the directories in `load-path' like `M-x load-library' | |
439 | to find the file that `M-x load-library RET LIBRARY RET' would load. | |
440 | Optional second arg NOSUFFIX non-nil means don't add suffixes `.elc' or `.el' | |
441 | to the specified name LIBRARY (a la calling `load' instead of `load-library')." | |
442 | (interactive "sLocate library: ") | |
443 | (catch 'answer | |
444 | (mapcar | |
445 | '(lambda (dir) | |
446 | (mapcar | |
447 | '(lambda (suf) | |
448 | (let ((try (expand-file-name (concat library suf) dir))) | |
449 | (and (file-readable-p try) | |
450 | (null (file-directory-p try)) | |
451 | (progn | |
452 | (message "Library is file %s" try) | |
453 | (throw 'answer try))))) | |
454 | (if nosuffix '("") '(".elc" ".el" "")))) | |
455 | load-path) | |
456 | (message "No library %s in search path" library) | |
457 | nil)) | |
1a06eabd ER |
458 | |
459 | ;;; help.el ends here |