1 ;;; help.el --- help commands for Emacs
3 ;; Copyright (C) 1985, 1986, 1993, 1994, 1998, 1999, 2000, 2001, 2002,
4 ;; 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
7 ;; Keywords: help, internal
9 ;; This file is part of GNU Emacs.
11 ;; GNU Emacs is free software; you can redistribute it and/or modify
12 ;; it under the terms of the GNU General Public License as published by
13 ;; the Free Software Foundation; either version 2, or (at your option)
16 ;; GNU Emacs is distributed in the hope that it will be useful,
17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 ;; GNU General Public License for more details.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with GNU Emacs; see the file COPYING. If not, write to the
23 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
24 ;; Boston, MA 02110-1301, USA.
28 ;; This code implements GNU Emacs' on-line help system, the one invoked by
29 ;; `M-x help-for-help'.
33 ;; Get the macro make-help-screen when this is compiled,
34 ;; or run interpreted, but not when the compiled code is loaded.
35 (eval-when-compile (require 'help-macro
))
37 ;; This makes `with-output-to-temp-buffer' buffers use `help-mode'.
38 (add-hook 'temp-buffer-setup-hook
'help-mode-setup
)
39 (add-hook 'temp-buffer-show-hook
'help-mode-finish
)
42 (let ((map (make-sparse-keymap)))
43 (define-key map
(char-to-string help-char
) 'help-for-help
)
44 (define-key map
[help] 'help-for-help)
45 (define-key map [f1] 'help-for-help)
46 (define-key map "." 'display-local-help)
47 (define-key map "?" 'help-for-help)
49 (define-key map "\C-c" 'describe-copying)
50 (define-key map "\C-d" 'describe-distribution)
51 (define-key map "\C-e" 'view-emacs-problems)
52 (define-key map "\C-f" 'view-emacs-FAQ)
53 (define-key map "\C-m" 'view-order-manuals)
54 (define-key map "\C-n" 'view-emacs-news)
55 (define-key map "\C-p" 'describe-project)
56 (define-key map "\C-t" 'view-todo)
57 (define-key map "\C-w" 'describe-no-warranty)
59 ;; This does not fit the pattern, but it is natural given the C-\ command.
60 (define-key map "\C-\\" 'describe-input-method)
62 (define-key map "C" 'describe-coding-system)
63 (define-key map "F" 'Info-goto-emacs-command-node)
64 (define-key map "I" 'describe-input-method)
65 (define-key map "K" 'Info-goto-emacs-key-command-node)
66 (define-key map "L" 'describe-language-environment)
67 (define-key map "S" 'info-lookup-symbol)
69 (define-key map "a" 'apropos-command)
70 (define-key map "b" 'describe-bindings)
71 (define-key map "c" 'describe-key-briefly)
72 (define-key map "d" 'apropos-documentation)
73 (define-key map "e" 'view-echo-area-messages)
74 (define-key map "f" 'describe-function)
75 (define-key map "h" 'view-hello-file)
77 (define-key map "i" 'info)
78 (define-key map "4i" 'info-other-window)
80 (define-key map "k" 'describe-key)
81 (define-key map "l" 'view-lossage)
82 (define-key map "m" 'describe-mode)
83 (define-key map "n" 'view-emacs-news)
84 (define-key map "p" 'finder-by-keyword)
85 (define-key map "r" 'info-emacs-manual)
86 (define-key map "s" 'describe-syntax)
87 (define-key map "t" 'help-with-tutorial)
88 (define-key map "w" 'where-is)
89 (define-key map "v" 'describe-variable)
90 (define-key map "q" 'help-quit)
92 "Keymap for characters following the Help key.")
94 (define-key global-map (char-to-string help-char) 'help-command)
95 (define-key global-map [help] 'help-command
)
96 (define-key global-map
[f1] 'help-command)
97 (fset 'help-command help-map)
99 (autoload 'finder-by-keyword "finder"
100 "Find packages matching a given keyword." t)
102 ;; insert-button makes the action nil if it is not store somewhere
103 (defvar help-button-cache nil)
107 "Just exit from the Help command's command loop."
111 (defvar help-return-method nil
112 "What to do to \"exit\" the help buffer.
114 (WINDOW . t) delete the selected window (and possibly its frame,
115 see `quit-window' and `View-quit'), go to WINDOW.
116 (WINDOW . quit-window) do quit-window, then select WINDOW.
117 (WINDOW BUF START POINT) display BUF at START, POINT, then select WINDOW.")
119 (defun print-help-return-message (&optional function)
120 "Display or return message saying how to restore windows after help command.
121 This function assumes that `standard-output' is the help buffer.
122 It computes a message, and applies the optional argument FUNCTION to it.
123 If FUNCTION is nil, it applies `message', thus displaying the message.
124 In addition, this function sets up `help-return-method', which see, that
125 specifies what to do when the user exits the help buffer."
126 (and (not (get-buffer-window standard-output))
130 (special-display-p (buffer-name standard-output)))
131 (setq help-return-method (cons (selected-window) t))
132 ;; If the help output buffer is a special display buffer,
133 ;; don't say anything about how to get rid of it.
134 ;; First of all, the user will do that with the window
135 ;; manager, not with Emacs.
136 ;; Secondly, the buffer has not been displayed yet,
137 ;; so we don't know whether its frame will be selected.
139 (display-buffer-reuse-frames
140 (setq help-return-method (cons (selected-window)
143 ((not (one-window-p t))
144 (setq help-return-method
145 (cons (selected-window) 'quit-window))
146 "Type \\[display-buffer] RET to restore the other window.")
148 (setq help-return-method (cons (selected-window) t))
149 "Type \\[delete-other-windows] to remove help window.")
151 (setq help-return-method
152 (list (selected-window) (window-buffer)
153 (window-start) (window-point)))
154 "Type \\[switch-to-buffer] RET to remove help window."))))
155 (funcall (or function 'message)
158 (substitute-command-keys first-message))
159 (if first-message " ")
160 ;; If the help buffer will go in a separate frame,
161 ;; it's no use mentioning a command to scroll, so don't.
162 (if (or pop-up-windows
163 (special-display-p (buffer-name standard-output)))
165 (if (same-window-p (buffer-name standard-output))
166 ;; Say how to scroll this window.
167 (substitute-command-keys
168 "\\[scroll-up] to scroll the help.")
169 ;; Say how to scroll some other window.
170 (substitute-command-keys
171 "\\[scroll-other-window] to scroll the help."))))))))
173 ;; So keyboard macro definitions are documented correctly
174 (fset 'defining-kbd-macro (symbol-function 'start-kbd-macro))
176 (defalias 'help 'help-for-help-internal)
177 ;; find-function can find this.
178 (defalias 'help-for-help 'help-for-help-internal)
179 ;; It can't find this, but nobody will look.
180 (make-help-screen help-for-help-internal
181 "a b c C e f F i I k C-k l L m p r s t v w C-c C-d C-f C-n C-p C-t C-w . or ? :"
182 "You have typed %THIS-KEY%, the help character. Type a Help option:
183 \(Use SPC or DEL to scroll through this text. Type \\<help-map>\\[help-quit] to exit the Help command.)
185 a command-apropos. Type a list of words or a regexp; it shows a list of
186 commands whose names match. See also the apropos command.
187 b describe-bindings. Display a table of all key bindings.
188 c describe-key-briefly. Type a key sequence;
189 it displays the command name run by that key sequence.
190 C describe-coding-system. Type the name of the coding system to describe,
191 or just RET to describe the ones currently in use.
192 d apropos-documentation. Type a pattern (a list of words or a regexp), and
193 it shows a list of functions, variables, and other items whose
194 documentation matches that pattern. See also the apropos command.
195 e view-echo-area-messages. Go to the buffer that logs echo-area messages.
196 f describe-function. Type a function name and you see its documentation.
197 F Info-goto-emacs-command-node. Type a command name;
198 it goes to the on-line manual's section that describes the command.
199 h Display the HELLO file which illustrates various scripts.
200 i info. The Info documentation reader: read on-line manuals.
201 I describe-input-method. Describe a specific input method (if you type
202 its name) or the current input method (if you type just RET).
203 k describe-key. Type a key sequence;
204 it displays the full documentation for that key sequence.
205 K Info-goto-emacs-key-command-node. Type a key sequence;
206 it goes to the on-line manual's section that describes
207 the command bound to that key.
208 l view-lossage. Show last 100 characters you typed.
209 L describe-language-environment. This describes either a
210 specific language environment (if you type its name)
211 or the current language environment (if you type just RET).
212 m describe-mode. Display documentation of current minor modes,
213 and the current major mode, including their special commands.
214 n view-emacs-news. Display news of recent Emacs changes.
215 p finder-by-keyword. Find packages matching a given topic keyword.
216 r info-emacs-manual. Display the Emacs manual in Info mode.
217 s describe-syntax. Display contents of syntax table, plus explanations.
218 S info-lookup-symbol. Type a symbol; it goes to that symbol in the
219 on-line manual for the programming language used in this buffer.
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 a command name; it displays which keystrokes
225 . display-local-help. Display any available local help at point
228 C-c Display Emacs copying permission (GNU General Public License).
229 C-d Display Emacs ordering information.
230 C-e Display info about Emacs problems.
231 C-f Display the Emacs FAQ.
232 C-m Display how to order printed Emacs manuals.
233 C-n Display news of recent Emacs changes.
234 C-p Display information about the GNU project.
235 C-t Display the Emacs TODO list.
236 C-w Display information on absence of warranty for GNU Emacs."
241 (defun function-called-at-point ()
242 "Return a function around point or else called by the list containing point.
243 If that doesn't give a function, return nil."
244 (or (with-syntax-table emacs-lisp-mode-syntax-table
245 (or (condition-case ()
247 (or (not (zerop (skip-syntax-backward "_w")))
248 (eq (char-syntax (following-char)) ?w)
249 (eq (char-syntax (following-char)) ?_)
251 (skip-chars-forward "'")
252 (let ((obj (read (current-buffer))))
253 (and (symbolp obj) (fboundp obj) obj)))
258 (narrow-to-region (max (point-min)
259 (- (point) 1000)) (point-max))
260 ;; Move up to surrounding paren, then after the open.
263 ;; If there is space here, this is probably something
264 ;; other than a real Lisp function call, so ignore it.
265 (if (looking-at "[ \t]")
266 (error "Probably not a Lisp function call"))
267 (let ((obj (read (current-buffer))))
268 (and (symbolp obj) (fboundp obj) obj))))
270 (let* ((str (find-tag-default))
271 (sym (if str (intern-soft str))))
272 (if (and sym (fboundp sym))
275 (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str))
276 (setq sym (intern-soft (match-string 1 str)))
277 (and (fboundp sym) sym)))))))
280 ;;; `User' help functions
282 (defun describe-distribution ()
283 "Display info on how to obtain the latest version of GNU Emacs."
285 (view-file (expand-file-name "DISTRIB" data-directory)))
287 (defun describe-copying ()
288 "Display info on how you may redistribute copies of GNU Emacs."
290 (view-file (expand-file-name "COPYING" data-directory))
291 (goto-char (point-min)))
293 (defun describe-project ()
294 "Display info on the GNU project."
296 (view-file (expand-file-name "THE-GNU-PROJECT" data-directory))
297 (goto-char (point-min)))
299 (defun describe-no-warranty ()
300 "Display info on all the kinds of warranty Emacs does NOT have."
303 (let (case-fold-search)
304 (search-forward "NO WARRANTY")
307 (defun describe-prefix-bindings ()
308 "Describe the bindings of the prefix used to reach this command.
309 The prefix described consists of all but the last event
310 of the key sequence that ran this command."
312 (let ((key (this-command-keys)))
315 (substring key 0 (1- (length key)))
316 (let ((prefix (make-vector (1- (length key)) nil))
318 (while (< i (length prefix))
319 (aset prefix i (aref key i))
322 ;; Make C-h after a prefix, when not specifically bound,
323 ;; run describe-prefix-bindings.
324 (setq prefix-help-command 'describe-prefix-bindings)
326 (defun view-emacs-news (&optional version)
327 "Display info on recent changes to Emacs.
328 With argument, display info only for the selected version."
331 (setq version emacs-major-version))
332 (when (consp version)
338 (insert-file-contents
339 (expand-file-name file data-directory))
340 (while (re-search-forward
341 (if (member file '("NEWS.18" "NEWS.1-17"))
342 "Changes in \\(?:Emacs\\|version\\)?[ \t]*\\([0-9]+\\(?:\\.[0-9]+\\)?\\)"
343 "^\* [^0-9\n]*\\([0-9]+\\.[0-9]+\\)") nil t)
344 (setq res (cons (match-string-no-properties 1) res)))))
346 (directory-files data-directory nil
347 "^NEWS\\.[0-9][-0-9]*$" nil)))
348 (sort (delete-dups res) (lambda (a b) (string< b a)))))
349 (current (car all-versions)))
350 (setq version (completing-read
351 (format "Read NEWS for the version (default %s): " current)
352 all-versions nil nil nil nil current))
353 (if (integerp (string-to-number version))
354 (setq version (string-to-number version))
355 (unless (or (member version all-versions)
356 (<= (string-to-number version) (string-to-number current)))
357 (error "No news about version %s" version)))))
358 (when (integerp version)
359 (cond ((<= version 12)
360 (setq version (format "1.%d" version)))
362 (setq version (format "%d" version)))
363 ((> version emacs-major-version)
364 (error "No news about emacs %d (yet)" version))))
365 (let* ((vn (if (stringp version)
366 (string-to-number version)
369 ((>= vn emacs-major-version) "NEWS")
370 ((< vn 18) "NEWS.1-17")
371 (t (format "NEWS.%d" vn))))
373 (view-file (expand-file-name file data-directory))
375 (goto-char (point-min))
376 (when (stringp version)
377 (when (re-search-forward
378 (concat (if (< vn 19)
379 "Changes in Emacs[ \t]*"
380 "^\* [^0-9\n]*") version "$")
386 (while (and (setq res
389 "Changes in \\(?:Emacs\\|version\\)?[ \t]*\\([0-9]+\\(?:\\.[0-9]+\\)?\\)"
390 "^\* [^0-9\n]*\\([0-9]+\\.[0-9]+\\)") nil t))
391 (equal (match-string-no-properties 1) version)))
392 (or res (goto-char (point-max)))
397 (defun view-todo (&optional arg)
398 "Display the Emacs TODO list."
400 (view-file (expand-file-name "TODO" data-directory)))
402 (defun view-echo-area-messages ()
403 "View the log of recent echo-area messages: the `*Messages*' buffer.
404 The number of messages retained in that buffer
405 is specified by the variable `message-log-max'."
407 (switch-to-buffer (get-buffer-create "*Messages*")))
409 (defun view-order-manuals ()
410 "Display the Emacs ORDERS file."
412 (view-file (expand-file-name "ORDERS" data-directory))
415 (defun view-emacs-FAQ ()
416 "Display the Emacs Frequently Asked Questions (FAQ) file."
418 ;; (find-file-read-only (expand-file-name "FAQ" data-directory))
421 (defun view-emacs-problems ()
422 "Display info on known problems with Emacs and possible workarounds."
424 (view-file (expand-file-name "PROBLEMS" data-directory)))
426 (defun view-lossage ()
427 "Display last 100 input keystrokes.
429 To record all your input on a file, use `open-dribble-file'."
431 (help-setup-xref (list #'view-lossage) (interactive-p))
432 (with-output-to-temp-buffer (help-buffer)
433 (princ (mapconcat (lambda (key)
434 (if (or (integerp key) (symbolp key) (listp key))
435 (single-key-description key)
436 (prin1-to-string key nil)))
439 (with-current-buffer standard-output
440 (goto-char (point-min))
441 (while (progn (move-to-column 50) (not (eobp)))
442 (when (search-forward " " nil t)
445 (print-help-return-message)))
450 (defun describe-bindings (&optional prefix buffer)
451 "Show a list of all defined keys, and their definitions.
452 We put that list in a buffer, and display the buffer.
454 The optional argument PREFIX, if non-nil, should be a key sequence;
455 then we display only bindings that start with that prefix.
456 The optional argument BUFFER specifies which buffer's bindings
457 to display (default, the current buffer). BUFFER can be a buffer
460 (or buffer (setq buffer (current-buffer)))
461 (help-setup-xref (list #'describe-bindings prefix buffer) (interactive-p))
462 (with-current-buffer buffer
463 (describe-bindings-internal nil prefix)))
465 ;; This function used to be in keymap.c.
466 (defun describe-bindings-internal (&optional menus prefix)
467 "Show a list of all defined keys, and their definitions.
468 We put that list in a buffer, and display the buffer.
470 The optional argument MENUS, if non-nil, says to mention menu bindings.
471 \(Ordinarily these are omitted from the output.)
472 The optional argument PREFIX, if non-nil, should be a key sequence;
473 then we display only bindings that start with that prefix."
475 (let ((buf (current-buffer)))
476 (with-output-to-temp-buffer "*Help*"
477 (with-current-buffer standard-output
478 (describe-buffer-bindings buf prefix menus)))))
480 (defun where-is (definition &optional insert)
481 "Print message listing key sequences that invoke the command DEFINITION.
482 Argument is a command definition, usually a symbol with a function definition.
483 If INSERT (the prefix arg) is non-nil, insert the message in the buffer."
485 (let ((fn (function-called-at-point))
486 (enable-recursive-minibuffers t)
488 (setq val (completing-read
490 (format "Where is command (default %s): " fn)
491 "Where is command: ")
492 obarray 'commandp t))
493 (list (if (equal val "") fn (intern val)) current-prefix-arg)))
494 (let ((func (indirect-function definition))
496 (standard-output (if insert (current-buffer) t)))
497 ;; In DEFS, find all symbols that are aliases for DEFINITION.
498 (mapatoms (lambda (symbol)
499 (and (fboundp symbol)
500 (not (eq symbol definition))
501 (eq func (condition-case ()
502 (indirect-function symbol)
504 (push symbol defs))))
505 ;; Look at all the symbols--first DEFINITION,
507 (dolist (symbol (cons definition defs))
508 (let* ((remapped (command-remapping symbol))
509 (keys (where-is-internal
510 symbol overriding-local-map nil nil remapped))
511 (keys (mapconcat 'key-description keys ", "))
515 (if (> (length keys) 0)
517 (format "%s (%s) (remapped from %s)"
518 keys remapped symbol)
519 (format "%s (%s)" keys symbol))
520 (format "M-x %s RET" symbol))
521 (if (> (length keys) 0)
523 (format "%s is remapped to %s which is on %s"
524 symbol remapped keys)
525 (format "%s is on %s" symbol keys))
526 ;; If this is the command the user asked about,
527 ;; and it is not on any key, say so.
528 ;; For other symbols, its aliases, say nothing
529 ;; about them unless they are on keys.
530 (if (eq symbol definition)
531 (format "%s is not on any key" symbol)))))
533 (unless (eq symbol definition)
534 (princ ";\n its alias "))
538 (defun help-key-description (key untranslated)
539 (let ((string (key-description key)))
540 (if (or (not untranslated)
541 (and (eq (aref untranslated 0) ?\e) (not (eq (aref key 0) ?\e))))
543 (let ((otherstring (key-description untranslated)))
544 (if (equal string otherstring)
546 (format "%s (translated from %s)" string otherstring))))))
548 (defun describe-key-briefly (&optional key insert untranslated)
549 "Print the name of the function KEY invokes. KEY is a string.
550 If INSERT (the prefix arg) is non-nil, insert the message in the buffer.
551 If non-nil, UNTRANSLATED is a vector of the untranslated events.
552 It can also be a number in which case the untranslated events from
553 the last key hit are used.
555 If KEY is a menu item or a tool-bar button that is disabled, this command
556 temporarily enables it to allow getting help on disabled items and buttons."
558 (let ((enable-disabled-menus-and-buttons t)
559 (cursor-in-echo-area t)
563 ;; If yank-menu is empty, populate it temporarily, so that
564 ;; "Select and Paste" menu can generate a complete event.
565 (when (null (cdr yank-menu))
566 (setq saved-yank-menu (copy-sequence yank-menu))
567 (menu-bar-update-yank-menu "(any string)" nil))
568 (setq key (read-key-sequence "Describe key (or click or menu item): "))
569 ;; If KEY is a down-event, read and discard the
570 ;; corresponding up-event. Note that there are also
571 ;; down-events on scroll bars and mode lines: the actual
572 ;; event then is in the second element of the vector.
574 (or (and (eventp (aref key 0))
575 (memq 'down (event-modifiers (aref key 0))))
576 (and (> (length key) 1)
577 (eventp (aref key 1))
578 (memq 'down (event-modifiers (aref key 1)))))
582 (if current-prefix-arg (prefix-numeric-value current-prefix-arg))
584 ;; Put yank-menu back as it was, if we changed it.
585 (when saved-yank-menu
586 (setq yank-menu (copy-sequence saved-yank-menu))
587 (fset 'yank-menu (cons 'keymap yank-menu))))))
588 (if (numberp untranslated)
589 (setq untranslated (this-single-command-raw-keys)))
590 (let* ((event (if (and (symbolp (aref key 0))
592 (consp (aref key 1)))
595 (modifiers (event-modifiers event))
596 (standard-output (if insert (current-buffer) t))
597 (mouse-msg (if (or (memq 'click modifiers) (memq 'down modifiers)
598 (memq 'drag modifiers)) " at that spot" ""))
599 (defn (key-binding key t))
601 ;; Handle the case where we faked an entry in "Select and Paste" menu.
602 (if (and (eq defn nil)
603 (stringp (aref key (1- (length key))))
604 (eq (key-binding (substring key 0 -1)) 'yank-menu))
605 (setq defn 'menu-bar-select-yank))
606 ;; Don't bother user with strings from (e.g.) the select-paste menu.
607 (if (stringp (aref key (1- (length key))))
608 (aset key (1- (length key)) "(any string)"))
609 (if (and (> (length untranslated) 0)
610 (stringp (aref untranslated (1- (length untranslated)))))
611 (aset untranslated (1- (length untranslated)) "(any string)"))
612 ;; Now describe the key, perhaps as changed.
613 (setq key-desc (help-key-description key untranslated))
614 (if (or (null defn) (integerp defn) (equal defn 'undefined))
615 (princ (format "%s%s is undefined" key-desc mouse-msg))
616 (princ (format "%s%s runs the command %S" key-desc mouse-msg defn)))))
618 (defun describe-key (&optional key untranslated up-event)
619 "Display documentation of the function invoked by KEY.
620 KEY can be any kind of a key sequence; it can include keyboard events,
621 mouse events, and/or menu events. When calling from a program,
622 pass KEY as a string or a vector.
624 If non-nil, UNTRANSLATED is a vector of the corresponding untranslated events.
625 It can also be a number, in which case the untranslated events from
626 the last key sequence entered are used.
627 UP-EVENT is the up-event that was discarded by reading KEY, or nil.
629 If KEY is a menu item or a tool-bar button that is disabled, this command
630 temporarily enables it to allow getting help on disabled items and buttons."
632 (let ((enable-disabled-menus-and-buttons t)
633 (cursor-in-echo-area t)
637 ;; If yank-menu is empty, populate it temporarily, so that
638 ;; "Select and Paste" menu can generate a complete event.
639 (when (null (cdr yank-menu))
640 (setq saved-yank-menu (copy-sequence yank-menu))
641 (menu-bar-update-yank-menu "(any string)" nil))
642 (setq key (read-key-sequence "Describe key (or click or menu item): "))
645 (prefix-numeric-value current-prefix-arg)
646 ;; If KEY is a down-event, read the corresponding up-event
647 ;; and use it as the third argument.
649 (or (and (eventp (aref key 0))
650 (memq 'down (event-modifiers (aref key 0))))
651 (and (> (length key) 1)
652 (eventp (aref key 1))
653 (memq 'down (event-modifiers (aref key 1)))))
655 ;; Put yank-menu back as it was, if we changed it.
656 (when saved-yank-menu
657 (setq yank-menu (copy-sequence saved-yank-menu))
658 (fset 'yank-menu (cons 'keymap yank-menu))))))
659 (if (numberp untranslated)
660 (setq untranslated (this-single-command-raw-keys)))
661 (let* ((event (aref key (if (and (symbolp (aref key 0))
663 (consp (aref key 1)))
666 (modifiers (event-modifiers event))
667 (mouse-msg (if (or (memq 'click modifiers) (memq 'down modifiers)
668 (memq 'drag modifiers)) " at that spot" ""))
669 (defn (key-binding key t))
670 defn-up defn-up-tricky ev-type
671 mouse-1-remapped mouse-1-tricky)
673 ;; Handle the case where we faked an entry in "Select and Paste" menu.
674 (when (and (eq defn nil)
675 (stringp (aref key (1- (length key))))
676 (eq (key-binding (substring key 0 -1)) 'yank-menu))
677 (setq defn 'menu-bar-select-yank))
678 (if (or (null defn) (integerp defn) (equal defn 'undefined))
679 (message "%s%s is undefined"
680 (help-key-description key untranslated) mouse-msg)
681 (help-setup-xref (list #'describe-function defn) (interactive-p))
682 ;; Don't bother user with strings from (e.g.) the select-paste menu.
683 (when (stringp (aref key (1- (length key))))
684 (aset key (1- (length key)) "(any string)"))
685 (when (and untranslated
686 (stringp (aref untranslated (1- (length untranslated)))))
687 (aset untranslated (1- (length untranslated))
689 ;; Need to do this before erasing *Help* buffer in case event
690 ;; is a mouse click in an existing *Help* buffer.
692 (setq ev-type (event-basic-type up-event))
693 (let ((sequence (vector up-event)))
694 (when (and (eq ev-type 'mouse-1)
695 mouse-1-click-follows-link
696 (not (eq mouse-1-click-follows-link 'double))
697 (setq mouse-1-remapped
698 (mouse-on-link-p (event-start up-event))))
699 (setq mouse-1-tricky (and (integerp mouse-1-click-follows-link)
700 (> mouse-1-click-follows-link 0)))
701 (cond ((stringp mouse-1-remapped)
702 (setq sequence mouse-1-remapped))
703 ((vectorp mouse-1-remapped)
704 (setcar up-event (elt mouse-1-remapped 0)))
705 (t (setcar up-event 'mouse-2))))
706 (setq defn-up (key-binding sequence nil nil (event-start up-event)))
708 (setq sequence (vector up-event))
709 (aset sequence 0 'mouse-1)
710 (setq defn-up-tricky (key-binding sequence nil nil (event-start up-event))))))
711 (with-output-to-temp-buffer (help-buffer)
712 (princ (help-key-description key untranslated))
714 %s runs the command %S
717 (describe-function-1 defn)
719 (unless (or (null defn-up)
721 (equal defn-up 'undefined))
724 ----------------- up-event %s----------------
726 <%S>%s%s runs the command %S
728 (if mouse-1-tricky "(short click) " "")
731 " is remapped to <mouse-2>\nwhich" "")
733 (describe-function-1 defn-up))
734 (unless (or (null defn-up-tricky)
735 (integerp defn-up-tricky)
736 (eq defn-up-tricky 'undefined))
739 ----------------- up-event (long click) ----------------
741 Pressing <%S>%s for longer than %d milli-seconds
745 mouse-1-click-follows-link
747 (describe-function-1 defn-up-tricky)))
748 (print-help-return-message)))))
750 (defun describe-mode (&optional buffer)
751 "Display documentation of current major mode and minor modes.
752 A brief summary of the minor modes comes first, followed by the
753 major mode description. This is followed by detailed
754 descriptions of the minor modes, each on a separate page.
756 For this to work correctly for a minor mode, the mode's indicator
757 variable \(listed in `minor-mode-alist') must also be a function
758 whose documentation describes the minor mode."
760 (unless buffer (setq buffer (current-buffer)))
761 (help-setup-xref (list #'describe-mode buffer)
763 ;; For the sake of help-do-xref and help-xref-go-back,
764 ;; don't switch buffers before calling `help-buffer'.
765 (with-output-to-temp-buffer (help-buffer)
766 (with-current-buffer buffer
768 ;; Older packages do not register in minor-mode-list but only in
770 (dolist (x minor-mode-alist)
772 (unless (memq x minor-mode-list)
773 (push x minor-mode-list)))
774 ;; Find enabled minor mode we will want to mention.
775 (dolist (mode minor-mode-list)
776 ;; Document a minor mode if it is listed in minor-mode-alist,
777 ;; non-nil, and has a function definition.
778 (let ((fmode (or (get mode :minor-mode-function) mode)))
779 (and (boundp mode) (symbol-value mode)
781 (let ((pretty-minor-mode
782 (if (string-match "\\(\\(-minor\\)?-mode\\)?\\'"
785 (substring (symbol-name fmode)
786 0 (match-beginning 0)))
788 (push (list fmode pretty-minor-mode
789 (format-mode-line (assq mode minor-mode-alist)))
793 (lambda (a b) (string-lessp (cadr a) (cadr b)))))
795 (princ "Enabled minor modes:\n")
796 (make-local-variable 'help-button-cache)
797 (with-current-buffer standard-output
798 (dolist (mode minor-modes)
799 (let ((mode-function (nth 0 mode))
800 (pretty-minor-mode (nth 1 mode))
801 (indicator (nth 2 mode)))
802 (add-text-properties 0 (length pretty-minor-mode)
803 '(face bold) pretty-minor-mode)
805 (goto-char (point-max))
807 (push (point-marker) help-button-cache)
808 ;; Document the minor modes fully.
809 (insert pretty-minor-mode)
810 (princ (format " minor mode (%s):\n"
811 (if (zerop (length indicator))
813 (format "indicator%s"
815 (princ (documentation mode-function)))
816 (insert-button pretty-minor-mode
817 'action (car help-button-cache)
819 'help-echo "mouse-2, RET: show full information")
825 (princ "\n(Information about these minor modes follows the major mode info.)\n\n"))
826 ;; Document the major mode.
827 (let ((mode mode-name))
828 (with-current-buffer standard-output
829 (let ((start (point)))
830 (insert (format-mode-line mode))
831 (add-text-properties start (point) '(face bold)))))
833 (princ (documentation major-mode)))
834 (print-help-return-message))))
837 (defun describe-minor-mode (minor-mode)
838 "Display documentation of a minor mode given as MINOR-MODE.
839 MINOR-MODE can be a minor mode symbol or a minor mode indicator string
840 appeared on the mode-line."
841 (interactive (list (completing-read
844 (describe-minor-mode-completion-table-for-symbol)
845 (describe-minor-mode-completion-table-for-indicator)
847 (if (symbolp minor-mode)
848 (setq minor-mode (symbol-name minor-mode)))
849 (let ((symbols (describe-minor-mode-completion-table-for-symbol))
850 (indicators (describe-minor-mode-completion-table-for-indicator)))
852 ((member minor-mode symbols)
853 (describe-minor-mode-from-symbol (intern minor-mode)))
854 ((member minor-mode indicators)
855 (describe-minor-mode-from-indicator minor-mode))
857 (error "No such minor mode: %s" minor-mode)))))
860 (defun describe-minor-mode-completion-table-for-symbol ()
861 ;; In order to list up all minor modes, minor-mode-list
862 ;; is used here instead of minor-mode-alist.
863 (delq nil (mapcar 'symbol-name minor-mode-list)))
864 (defun describe-minor-mode-from-symbol (symbol)
865 "Display documentation of a minor mode given as a symbol, SYMBOL"
866 (interactive (list (intern (completing-read
867 "Minor mode symbol: "
868 (describe-minor-mode-completion-table-for-symbol)))))
870 (describe-function symbol)
871 (describe-variable symbol)))
874 (defun describe-minor-mode-completion-table-for-indicator ()
877 (let ((i (format-mode-line x)))
878 ;; remove first space if existed
887 (defun describe-minor-mode-from-indicator (indicator)
888 "Display documentation of a minor mode specified by INDICATOR.
889 If you call this function interactively, you can give indicator which
890 is currently activated with completion."
893 "Minor mode indicator: "
894 (describe-minor-mode-completion-table-for-indicator))))
895 (let ((minor-mode (lookup-minor-mode-from-indicator indicator)))
897 (describe-minor-mode-from-symbol minor-mode)
898 (error "Cannot find minor mode for `%s'" indicator))))
900 (defun lookup-minor-mode-from-indicator (indicator)
901 "Return a minor mode symbol from its indicator on the modeline."
902 ;; remove first space if existed
903 (if (and (< 0 (length indicator))
904 (eq (aref indicator 0) ?\ ))
905 (setq indicator (substring indicator 1)))
906 (let ((minor-modes minor-mode-alist)
909 (let* ((minor-mode (car (car minor-modes)))
910 (anindicator (format-mode-line
911 (car (cdr (car minor-modes))))))
912 ;; remove first space if existed
913 (if (and (stringp anindicator)
914 (> (length anindicator) 0)
915 (eq (aref anindicator 0) ?\ ))
916 (setq anindicator (substring anindicator 1)))
917 (if (equal indicator anindicator)
918 (setq result minor-mode
920 (setq minor-modes (cdr minor-modes)))))
924 ;;; Automatic resizing of temporary buffers.
926 (defcustom temp-buffer-max-height (lambda (buffer) (/ (- (frame-height) 2) 2))
927 "Maximum height of a window displaying a temporary buffer.
928 This is effective only when Temp Buffer Resize mode is enabled.
929 The value is the maximum height (in lines) which `resize-temp-buffer-window'
930 will give to a window displaying a temporary buffer.
931 It can also be a function to be called to choose the height for such a buffer.
932 It gets one argumemt, the buffer, and should return a positive integer."
933 :type '(choice integer function)
937 (define-minor-mode temp-buffer-resize-mode
938 "Toggle the mode which makes windows smaller for temporary buffers.
939 With prefix argument ARG, turn the resizing of windows displaying temporary
940 buffers on if ARG is positive or off otherwise.
941 This makes the window the right height for its contents, but never
942 more than `temp-buffer-max-height' nor less than `window-min-height'.
943 This applies to `help', `apropos' and `completion' buffers, and some others."
944 :global t :group 'help
945 (if temp-buffer-resize-mode
946 ;; `help-make-xrefs' may add a `back' button and thus increase the
947 ;; text size, so `resize-temp-buffer-window' must be run *after* it.
948 (add-hook 'temp-buffer-show-hook 'resize-temp-buffer-window 'append)
949 (remove-hook 'temp-buffer-show-hook 'resize-temp-buffer-window)))
951 (defun resize-temp-buffer-window ()
952 "Resize the current window to fit its contents.
953 Will not make it higher than `temp-buffer-max-height' nor smaller than
954 `window-min-height'. Do nothing if it is the only window on its frame, if it
955 is not as wide as the frame or if some of the window's contents are scrolled
957 (unless (or (one-window-p 'nomini)
958 (not (pos-visible-in-window-p (point-min)))
959 (/= (frame-width) (window-width)))
960 (fit-window-to-buffer
962 (if (functionp temp-buffer-max-height)
963 (funcall temp-buffer-max-height (current-buffer))
964 temp-buffer-max-height))))
969 ;; arch-tag: cf427352-27e9-49b7-9a6f-741ebab02423
970 ;;; help.el ends here