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1a06eabd ER |
1 | ;;; help.el --- help commands for Emacs |
2 | ||
3a801d0c ER |
3 | ;; Copyright (C) 1985, 1986 Free Software Foundation, Inc. |
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 | ||
e5167999 ER |
24 | ;;; Code: |
25 | ||
41b8542b ER |
26 | (require 'help-screen) |
27 | ||
433ae6f6 RS |
28 | (defvar help-map (make-sparse-keymap) |
29 | "Keymap for characters following the Help key.") | |
30 | ||
e17d2fd1 | 31 | (define-key global-map (char-to-string help-char) 'help-command) |
433ae6f6 RS |
32 | (fset 'help-command help-map) |
33 | ||
e17d2fd1 | 34 | (define-key help-map (char-to-string help-char) 'help-for-help) |
433ae6f6 RS |
35 | (define-key help-map "?" 'help-for-help) |
36 | ||
37 | (define-key help-map "\C-c" 'describe-copying) | |
38 | (define-key help-map "\C-d" 'describe-distribution) | |
39 | (define-key help-map "\C-w" 'describe-no-warranty) | |
40 | (define-key help-map "a" 'command-apropos) | |
41 | ||
42 | (define-key help-map "b" 'describe-bindings) | |
43 | ||
44 | (define-key help-map "c" 'describe-key-briefly) | |
45 | (define-key help-map "k" 'describe-key) | |
46 | ||
47 | (define-key help-map "d" 'describe-function) | |
48 | (define-key help-map "f" 'describe-function) | |
49 | ||
50 | (define-key help-map "i" 'info) | |
e5d77022 JB |
51 | (define-key help-map "\C-f" 'Info-goto-emacs-command-node) |
52 | (define-key help-map "\C-k" 'Info-goto-emacs-key-command-node) | |
433ae6f6 RS |
53 | |
54 | (define-key help-map "l" 'view-lossage) | |
55 | ||
56 | (define-key help-map "m" 'describe-mode) | |
57 | ||
58 | (define-key help-map "\C-n" 'view-emacs-news) | |
59 | (define-key help-map "n" 'view-emacs-news) | |
60 | ||
06b98c51 ER |
61 | (define-key help-map "p" 'finder-by-keyword) |
62 | (autoload 'finder-by-keyword "finder.el") | |
63 | ||
433ae6f6 RS |
64 | (define-key help-map "s" 'describe-syntax) |
65 | ||
66 | (define-key help-map "t" 'help-with-tutorial) | |
67 | ||
68 | (define-key help-map "w" 'where-is) | |
69 | ||
70 | (define-key help-map "v" 'describe-variable) | |
71 | ||
72 | (defun help-with-tutorial () | |
73 | "Select the Emacs learn-by-doing tutorial." | |
74 | (interactive) | |
75 | (let ((file (expand-file-name "~/TUTORIAL"))) | |
76 | (delete-other-windows) | |
77 | (if (get-file-buffer file) | |
78 | (switch-to-buffer (get-file-buffer file)) | |
79 | (switch-to-buffer (create-file-buffer file)) | |
80 | (setq buffer-file-name file) | |
81 | (setq default-directory (expand-file-name "~/")) | |
79058860 | 82 | (setq buffer-auto-save-file-name nil) |
1e6dacf6 | 83 | (insert-file-contents (expand-file-name "TUTORIAL" data-directory)) |
433ae6f6 RS |
84 | (goto-char (point-min)) |
85 | (search-forward "\n<<") | |
86 | (beginning-of-line) | |
87 | (delete-region (point) (progn (end-of-line) (point))) | |
88 | (newline (- (window-height (selected-window)) | |
89 | (count-lines (point-min) (point)) | |
90 | 6)) | |
91 | (goto-char (point-min)) | |
92 | (set-buffer-modified-p nil)))) | |
93 | ||
94 | (defun describe-key-briefly (key) | |
95 | "Print the name of the function KEY invokes. KEY is a string." | |
96 | (interactive "kDescribe key briefly: ") | |
97 | (let ((defn (key-binding key))) | |
98 | (if (or (null defn) (integerp defn)) | |
99 | (message "%s is undefined" (key-description key)) | |
100 | (message "%s runs the command %s" | |
101 | (key-description key) | |
102 | (if (symbolp defn) defn (prin1-to-string defn)))))) | |
103 | ||
104 | (defun print-help-return-message (&optional function) | |
105 | "Display or return message saying how to restore windows after help command. | |
106 | Computes a message and applies the optional argument FUNCTION to it. | |
107 | If FUNCTION is nil, applies `message' to it, thus printing it." | |
108 | (and (not (get-buffer-window standard-output)) | |
109 | (funcall (or function 'message) | |
110 | (concat | |
111 | (substitute-command-keys | |
112 | (if (one-window-p t) | |
113 | (if pop-up-windows | |
114 | "Type \\[delete-other-windows] to remove help window." | |
115 | "Type \\[switch-to-buffer] RET to remove help window.") | |
116 | "Type \\[switch-to-buffer-other-window] RET to restore the other window.")) | |
117 | (substitute-command-keys | |
118 | " \\[scroll-other-window] to scroll the help."))))) | |
119 | ||
120 | (defun describe-key (key) | |
121 | "Display documentation of the function invoked by KEY. KEY is a string." | |
122 | (interactive "kDescribe key: ") | |
123 | (let ((defn (key-binding key))) | |
124 | (if (or (null defn) (integerp defn)) | |
125 | (message "%s is undefined" (key-description key)) | |
126 | (with-output-to-temp-buffer "*Help*" | |
127 | (prin1 defn) | |
128 | (princ ":\n") | |
129 | (if (documentation defn) | |
130 | (princ (documentation defn)) | |
131 | (princ "not documented")) | |
132 | (print-help-return-message))))) | |
133 | ||
134 | (defun describe-mode (&optional minor) | |
135 | "Display documentation of current major mode. | |
136 | If optional MINOR is non-nil (or prefix argument is given if interactive), | |
137 | display documentation of active minor modes as well. | |
138 | For this to work correctly for a minor mode, the mode's indicator variable | |
139 | (listed in `minor-mode-alist') must also be a function whose documentation | |
140 | describes the minor mode." | |
141 | (interactive) | |
142 | (with-output-to-temp-buffer "*Help*" | |
143 | (princ mode-name) | |
144 | (princ " Mode:\n") | |
145 | (princ (documentation major-mode)) | |
146 | (let ((minor-modes minor-mode-alist) | |
147 | (locals (buffer-local-variables))) | |
148 | (while minor-modes | |
149 | (let* ((minor-mode (car (car minor-modes))) | |
150 | (indicator (car (cdr (car minor-modes)))) | |
151 | (local-binding (assq minor-mode locals))) | |
152 | ;; Document a minor mode if it is listed in minor-mode-alist, | |
153 | ;; bound locally in this buffer, non-nil, and has a function | |
154 | ;; definition. | |
155 | (if (and local-binding | |
156 | (cdr local-binding) | |
157 | (fboundp minor-mode)) | |
158 | (progn | |
159 | (princ (format "\n\n\n%s minor mode (indicator%s):\n" | |
160 | minor-mode indicator)) | |
161 | (princ (documentation minor-mode))))) | |
162 | (setq minor-modes (cdr minor-modes)))) | |
163 | (print-help-return-message))) | |
164 | ||
165 | ;; So keyboard macro definitions are documented correctly | |
166 | (fset 'defining-kbd-macro (symbol-function 'start-kbd-macro)) | |
167 | ||
168 | (defun describe-distribution () | |
169 | "Display info on how to obtain the latest version of GNU Emacs." | |
170 | (interactive) | |
171 | (find-file-read-only | |
1e6dacf6 | 172 | (expand-file-name "DISTRIB" data-directory))) |
433ae6f6 RS |
173 | |
174 | (defun describe-copying () | |
175 | "Display info on how you may redistribute copies of GNU Emacs." | |
176 | (interactive) | |
177 | (find-file-read-only | |
1e6dacf6 | 178 | (expand-file-name "COPYING" data-directory)) |
433ae6f6 RS |
179 | (goto-char (point-min))) |
180 | ||
181 | (defun describe-no-warranty () | |
182 | "Display info on all the kinds of warranty Emacs does NOT have." | |
183 | (interactive) | |
184 | (describe-copying) | |
185 | (let (case-fold-search) | |
186 | (search-forward "NO WARRANTY") | |
187 | (recenter 0))) | |
188 | ||
189 | (defun view-emacs-news () | |
190 | "Display info on recent changes to Emacs." | |
191 | (interactive) | |
1e6dacf6 | 192 | (find-file-read-only (expand-file-name "NEWS" data-directory))) |
433ae6f6 RS |
193 | |
194 | (defun view-lossage () | |
195 | "Display last 100 input keystrokes." | |
196 | (interactive) | |
197 | (with-output-to-temp-buffer "*Help*" | |
198 | (princ (key-description (recent-keys))) | |
199 | (save-excursion | |
200 | (set-buffer standard-output) | |
201 | (goto-char (point-min)) | |
202 | (while (progn (move-to-column 50) (not (eobp))) | |
203 | (search-forward " " nil t) | |
204 | (insert "\n"))) | |
205 | (print-help-return-message))) | |
206 | ||
41b8542b ER |
207 | (make-help-screen help-for-help |
208 | "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 | 209 | "You have typed \\[help-for-help], the help character. Type a Help option: |
433ae6f6 RS |
210 | |
211 | A command-apropos. Give a substring, and see a list of commands | |
212 | (functions interactively callable) that contain | |
213 | that substring. See also the apropos command. | |
214 | B describe-bindings. Display table of all key bindings. | |
215 | C describe-key-briefly. Type a command key sequence; | |
216 | it prints the function name that sequence runs. | |
217 | F describe-function. Type a function name and get documentation of it. | |
218 | I info. The info documentation reader. | |
219 | K describe-key. Type a command key sequence; | |
220 | it displays the full documentation. | |
221 | L view-lossage. Shows last 100 characters you typed. | |
222 | M describe-mode. Print documentation of current major mode, | |
223 | which describes the commands peculiar to it. | |
224 | N view-emacs-news. Shows emacs news file. | |
06b98c51 | 225 | P finder-by-keyword. Find packages matching a given topic keyword. |
433ae6f6 RS |
226 | S describe-syntax. Display contents of syntax table, plus explanations |
227 | T help-with-tutorial. Select the Emacs learn-by-doing tutorial. | |
228 | V describe-variable. Type name of a variable; | |
229 | it displays the variable's documentation and value. | |
230 | W where-is. Type command name; it prints which keystrokes | |
231 | invoke that command. | |
232 | C-c print Emacs copying permission (General Public License). | |
233 | C-d print Emacs ordering information. | |
234 | C-n print news of recent Emacs changes. | |
235 | C-w print information on absence of warranty for GNU Emacs." | |
41b8542b | 236 | help-map) |
433ae6f6 RS |
237 | |
238 | ;; Return a function which is called by the list containing point. | |
239 | ;; If that gives no function, return a function whose name is around point. | |
240 | ;; If that doesn't give a function, return nil. | |
241 | (defun function-called-at-point () | |
242 | (or (condition-case () | |
243 | (save-excursion | |
244 | (save-restriction | |
245 | (narrow-to-region (max (point-min) (- (point) 1000)) (point-max)) | |
246 | (backward-up-list 1) | |
247 | (forward-char 1) | |
248 | (let (obj) | |
249 | (setq obj (read (current-buffer))) | |
250 | (and (symbolp obj) (fboundp obj) obj)))) | |
251 | (error nil)) | |
252 | (condition-case () | |
253 | (save-excursion | |
254 | (forward-sexp -1) | |
255 | (skip-chars-forward "'") | |
256 | (let ((obj (read (current-buffer)))) | |
257 | (and (symbolp obj) (fboundp obj) obj))) | |
258 | (error nil)))) | |
259 | ||
260 | (defun describe-function (function) | |
261 | "Display the full documentation of FUNCTION (a symbol)." | |
262 | (interactive | |
263 | (let ((fn (function-called-at-point)) | |
264 | (enable-recursive-minibuffers t) | |
265 | val) | |
266 | (setq val (completing-read (if fn | |
267 | (format "Describe function (default %s): " fn) | |
268 | "Describe function: ") | |
269 | obarray 'fboundp t)) | |
270 | (list (if (equal val "") | |
271 | fn (intern val))))) | |
272 | (with-output-to-temp-buffer "*Help*" | |
273 | (prin1 function) | |
274 | (princ ": ") | |
275 | (let* ((def (symbol-function function)) | |
276 | (beg (if (commandp def) "an interactive " "a "))) | |
277 | (princ (cond ((stringp def) "a keyboard macro.") | |
278 | ((subrp def) | |
279 | (concat beg "built-in function.")) | |
dbc4e1c1 | 280 | ((byte-code-function-p def) |
433ae6f6 RS |
281 | (concat beg "compiled Lisp function.")) |
282 | ((symbolp def) | |
283 | (format "alias for `%s'." def)) | |
284 | ((eq (car-safe def) 'lambda) | |
285 | (concat beg "Lisp function.")) | |
286 | ((eq (car-safe def) 'macro) | |
287 | "a Lisp macro.") | |
288 | ((eq (car-safe def) 'mocklisp) | |
289 | "a mocklisp function.") | |
290 | ((eq (car-safe def) 'autoload) | |
762435dd RS |
291 | (format "%s autoloaded Lisp %s." |
292 | (if (commandp def) "an interactive" "an") | |
433ae6f6 | 293 | (if (nth 4 def) "macro" "function") |
ab67260b RS |
294 | ;;; Including the file name made this line too long. |
295 | ;;; (nth 1 def) | |
296 | )) | |
433ae6f6 | 297 | (t ""))) |
4591cb90 RS |
298 | (terpri) |
299 | (if (documentation function) | |
300 | (princ (documentation function)) | |
301 | (princ "not documented")) | |
302 | (cond ((byte-code-function-p def) | |
303 | (save-excursion | |
304 | (set-buffer standard-output) | |
305 | (or (eq (char-after (1- (point-max))) ?\n) | |
306 | (terpri))) | |
307 | (terpri) | |
308 | (princ (car (append def nil)))) | |
309 | ((eq (car-safe def) 'lambda) | |
310 | (save-excursion | |
311 | (set-buffer standard-output) | |
312 | (or (eq (char-after (1- (point-max))) ?\n) | |
313 | (terpri))) | |
314 | (terpri) | |
315 | (princ (nth 1 def))))) | |
433ae6f6 RS |
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)))) | |
78e3ef3c RS |
368 | (if (apropos string t 'commandp) |
369 | (and message (message message))))) | |
433ae6f6 RS |
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 |