1;;; help.el --- help commands for Emacs 2 3;; Copyright (C) 1985, 1986, 1993, 1994, 1998, 1999, 2000, 2001, 2002, 4;; 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc. 5 6;; Maintainer: FSF 7;; Keywords: help, internal 8 9;; This file is part of GNU Emacs. 10 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) 14;; any later version. 15 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. 20 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. 25 26;;; Commentary: 27 28;; This code implements GNU Emacs' on-line help system, the one invoked by 29;; `M-x help-for-help'. 30 31;;; Code: 32 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)) 36 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) 40 41(defvar help-map 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) 48 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) 58 59 ;; This does not fit the pattern, but it is natural given the C-\ command. 60 (define-key map "\C-\\" 'describe-input-method) 61 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) 68 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) 76 77 (define-key map "i" 'info) 78 (define-key map "4i" 'info-other-window) 79 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) 91 map) 92 "Keymap for characters following the Help key.") 93 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) 98 99(autoload 'finder-by-keyword "finder" 100 "Find packages matching a given keyword." t) 101 102;; insert-button makes the action nil if it is not store somewhere 103(defvar help-button-cache nil) 104 105 106(defun help-quit () 107 "Just exit from the Help command's command loop." 108 (interactive) 109 nil) 110 111(defvar help-return-method nil 112 "What to do to \"exit\" the help buffer. 113This is a list 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.") 118 119(defun print-help-return-message (&optional function) 120 "Display or return message saying how to restore windows after help command. 121This function assumes that `standard-output' is the help buffer. 122It computes a message, and applies the optional argument FUNCTION to it. 123If FUNCTION is nil, it applies `message', thus displaying the message. 124In addition, this function sets up `help-return-method', which see, that 125specifies what to do when the user exits the help buffer." 126 (and (not (get-buffer-window standard-output)) 127 (let ((first-message 128 (cond ((or 129 pop-up-frames 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. 138 nil) 139 (display-buffer-reuse-frames 140 (setq help-return-method (cons (selected-window) 141 'quit-window)) 142 nil) 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.") 147 (pop-up-windows 148 (setq help-return-method (cons (selected-window) t)) 149 "Type \\[delete-other-windows] to remove help window.") 150 (t 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) 156 (concat 157 (if first-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))) 164 nil 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.")))))))) 172 173;; So keyboard macro definitions are documented correctly 174(fset 'defining-kbd-macro (symbol-function 'start-kbd-macro)) 175 176(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.) 184 185a 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. 187b describe-bindings. Display a table of all key bindings. 188c describe-key-briefly. Type a key sequence; 189 it displays the command name run by that key sequence. 190C describe-coding-system. Type the name of the coding system to describe, 191 or just RET to describe the ones currently in use. 192d 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. 195e view-echo-area-messages. Go to the buffer that logs echo-area messages. 196f describe-function. Type a function name and you see its documentation. 197F Info-goto-emacs-command-node. Type a command name; 198 it goes to the on-line manual's section that describes the command. 199h Display the HELLO file which illustrates various scripts. 200i info. The Info documentation reader: read on-line manuals. 201I describe-input-method. Describe a specific input method (if you type 202 its name) or the current input method (if you type just RET). 203k describe-key. Type a key sequence; 204 it displays the full documentation for that key sequence. 205K 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. 208l view-lossage. Show last 100 characters you typed. 209L 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). 212m describe-mode. Display documentation of current minor modes, 213 and the current major mode, including their special commands. 214n view-emacs-news. Display news of recent Emacs changes. 215p finder-by-keyword. Find packages matching a given topic keyword. 216r info-emacs-manual. Display the Emacs manual in Info mode. 217s describe-syntax. Display contents of syntax table, plus explanations. 218S 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. 220t help-with-tutorial. Select the Emacs learn-by-doing tutorial. 221v describe-variable. Type name of a variable; 222 it displays the variable's documentation and value. 223w where-is. Type a command name; it displays which keystrokes 224 invoke that command. 225. display-local-help. Display any available local help at point 226 in the echo area. 227 228C-c Display Emacs copying permission (GNU General Public License). 229C-d Display Emacs ordering information. 230C-e Display info about Emacs problems. 231C-f Display the Emacs FAQ. 232C-m Display how to order printed Emacs manuals. 233C-n Display news of recent Emacs changes. 234C-p Display information about the GNU project. 235C-t Display the Emacs TODO list. 236C-w Display information on absence of warranty for GNU Emacs." 237 help-map) 238 239 240 241(defun function-called-at-point () 242 "Return a function around point or else called by the list containing point. 243If that doesn't give a function, return nil." 244 (or (with-syntax-table emacs-lisp-mode-syntax-table 245 (or (condition-case () 246 (save-excursion 247 (or (not (zerop (skip-syntax-backward "_w"))) 248 (eq (char-syntax (following-char)) ?w) 249 (eq (char-syntax (following-char)) ?_) 250 (forward-sexp -1)) 251 (skip-chars-forward "'") 252 (let ((obj (read (current-buffer)))) 253 (and (symbolp obj) (fboundp obj) obj))) 254 (error nil)) 255 (condition-case () 256 (save-excursion 257 (save-restriction 258 (narrow-to-region (max (point-min) 259 (- (point) 1000)) (point-max)) 260 ;; Move up to surrounding paren, then after the open. 261 (backward-up-list 1) 262 (forward-char 1) 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)))) 269 (error nil)))) 270 (let* ((str (find-tag-default)) 271 (sym (if str (intern-soft str)))) 272 (if (and sym (fboundp sym)) 273 sym 274 (save-match-data 275 (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str)) 276 (setq sym (intern-soft (match-string 1 str))) 277 (and (fboundp sym) sym))))))) 278 279 280;;; `User' help functions 281 282(defun describe-distribution () 283 "Display info on how to obtain the latest version of GNU Emacs." 284 (interactive) 285 (view-file (expand-file-name "DISTRIB" data-directory))) 286 287(defun describe-copying () 288 "Display info on how you may redistribute copies of GNU Emacs." 289 (interactive) 290 (view-file (expand-file-name "COPYING" data-directory)) 291 (goto-char (point-min))) 292 293(defun describe-project () 294 "Display info on the GNU project." 295 (interactive) 296 (view-file (expand-file-name "THE-GNU-PROJECT" data-directory)) 297 (goto-char (point-min))) 298 299(defun describe-no-warranty () 300 "Display info on all the kinds of warranty Emacs does NOT have." 301 (interactive) 302 (describe-copying) 303 (let (case-fold-search) 304 (search-forward "NO WARRANTY") 305 (recenter 0))) 306 307(defun describe-prefix-bindings () 308 "Describe the bindings of the prefix used to reach this command. 309The prefix described consists of all but the last event 310of the key sequence that ran this command." 311 (interactive) 312 (let ((key (this-command-keys))) 313 (describe-bindings 314 (if (stringp key) 315 (substring key 0 (1- (length key))) 316 (let ((prefix (make-vector (1- (length key)) nil)) 317 (i 0)) 318 (while (< i (length prefix)) 319 (aset prefix i (aref key i)) 320 (setq i (1+ i))) 321 prefix))))) 322;; Make C-h after a prefix, when not specifically bound, 323;; run describe-prefix-bindings. 324(setq prefix-help-command 'describe-prefix-bindings) 325 326(defun view-emacs-news (&optional version) 327 "Display info on recent changes to Emacs. 328With argument, display info only for the selected version." 329 (interactive "P") 330 (unless version 331 (setq version emacs-major-version)) 332 (when (consp version) 333 (let* ((all-versions 334 (let (res) 335 (mapcar 336 (lambda (file) 337 (with-temp-buffer 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))))) 345 (cons "NEWS" 346 (directory-files data-directory nil 347 "^NEWS\\.[0-9][-0-9]*$" nil))) 348 (sort (delete-dups res) (lambda (a b) (string< b a))))) 349 (current (car all-versions))) 350 (setq version (completing-read 351 (format "Read NEWS for the version (default %s): " current) 352 all-versions nil nil nil nil current)) 353 (if (integerp (string-to-number version)) 354 (setq version (string-to-number version)) 355 (unless (or (member version all-versions) 356 (<= (string-to-number version) (string-to-number current))) 357 (error "No news about version %s" version))))) 358 (when (integerp version) 359 (cond ((<= version 12) 360 (setq version (format "1.%d" version))) 361 ((<= version 18) 362 (setq version (format "%d" version))) 363 ((> version emacs-major-version) 364 (error "No news about Emacs %d (yet)" version)))) 365 (let* ((vn (if (stringp version) 366 (string-to-number version) 367 version)) 368 (file (cond 369 ((>= vn emacs-major-version) "NEWS") 370 ((< vn 18) "NEWS.1-17") 371 (t (format "NEWS.%d" vn)))) 372 res) 373 (view-file (expand-file-name file data-directory)) 374 (widen) 375 (goto-char (point-min)) 376 (when (stringp version) 377 (when (re-search-forward 378 (concat (if (< vn 19) 379 "Changes in Emacs[ \t]*" 380 "^\* [^0-9\n]*") version "$") 381 nil t) 382 (beginning-of-line) 383 (narrow-to-region 384 (point) 385 (save-excursion 386 (while (and (setq res 387 (re-search-forward 388 (if (< vn 19) 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))) 393 (beginning-of-line) 394 (point))))))) 395 396 397(defun view-todo (&optional arg) 398 "Display the Emacs TODO list." 399 (interactive "P") 400 (view-file (expand-file-name "TODO" data-directory))) 401 402(defun view-echo-area-messages () 403 "View the log of recent echo-area messages: the `*Messages*' buffer. 404The number of messages retained in that buffer 405is specified by the variable `message-log-max'." 406 (interactive) 407 (switch-to-buffer (get-buffer-create "*Messages*"))) 408 409(defun view-order-manuals () 410 "Display the Emacs ORDERS file." 411 (interactive) 412 (view-file (expand-file-name "ORDERS" data-directory)) 413 (goto-address)) 414 415(defun view-emacs-FAQ () 416 "Display the Emacs Frequently Asked Questions (FAQ) file." 417 (interactive) 418 ;; (find-file-read-only (expand-file-name "FAQ" data-directory)) 419 (info "(efaq)")) 420 421(defun view-emacs-problems () 422 "Display info on known problems with Emacs and possible workarounds." 423 (interactive) 424 (view-file (expand-file-name "PROBLEMS" data-directory))) 425 426(defun view-lossage () 427 "Display last 100 input keystrokes. 428 429To record all your input on a file, use `open-dribble-file'." 430 (interactive) 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))) 437 (recent-keys) 438 " ")) 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) 443 (delete-char -1)) 444 (insert "\n"))) 445 (print-help-return-message))) 446 447 448;; Key bindings 449 450(defun describe-bindings (&optional prefix buffer) 451 "Show a list of all defined keys, and their definitions. 452We put that list in a buffer, and display the buffer. 453 454The optional argument PREFIX, if non-nil, should be a key sequence; 455then we display only bindings that start with that prefix. 456The optional argument BUFFER specifies which buffer's bindings 457to display (default, the current buffer). BUFFER can be a buffer 458or a buffer name." 459 (interactive) 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))) 464 465;; 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. 468We put that list in a buffer, and display the buffer. 469 470The optional argument MENUS, if non-nil, says to mention menu bindings. 471\(Ordinarily these are omitted from the output.) 472The optional argument PREFIX, if non-nil, should be a key sequence; 473then we display only bindings that start with that prefix." 474 (interactive) 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))))) 479 480(defun where-is (definition &optional insert) 481 "Print message listing key sequences that invoke the command DEFINITION. 482Argument is a command definition, usually a symbol with a function definition. 483If INSERT (the prefix arg) is non-nil, insert the message in the buffer." 484 (interactive 485 (let ((fn (function-called-at-point)) 486 (enable-recursive-minibuffers t) 487 val) 488 (setq val (completing-read 489 (if fn 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 (unless definition (error "No command")) 495 (let ((func (indirect-function definition)) 496 (defs nil) 497 (standard-output (if insert (current-buffer) t))) 498 ;; In DEFS, find all symbols that are aliases for DEFINITION. 499 (mapatoms (lambda (symbol) 500 (and (fboundp symbol) 501 (not (eq symbol definition)) 502 (eq func (condition-case () 503 (indirect-function symbol) 504 (error symbol))) 505 (push symbol defs)))) 506 ;; Look at all the symbols--first DEFINITION, 507 ;; then its aliases. 508 (dolist (symbol (cons definition defs)) 509 (let* ((remapped (command-remapping symbol)) 510 (keys (where-is-internal 511 symbol overriding-local-map nil nil remapped)) 512 (keys (mapconcat 'key-description keys ", ")) 513 string) 514 (setq string 515 (if insert 516 (if (> (length keys) 0) 517 (if remapped 518 (format "%s (%s) (remapped from %s)" 519 keys remapped symbol) 520 (format "%s (%s)" keys symbol)) 521 (format "M-x %s RET" symbol)) 522 (if (> (length keys) 0) 523 (if remapped 524 (format "%s is remapped to %s which is on %s" 525 symbol remapped keys) 526 (format "%s is on %s" symbol keys)) 527 ;; If this is the command the user asked about, 528 ;; and it is not on any key, say so. 529 ;; For other symbols, its aliases, say nothing 530 ;; about them unless they are on keys. 531 (if (eq symbol definition) 532 (format "%s is not on any key" symbol))))) 533 (when string 534 (unless (eq symbol definition) 535 (princ ";\n its alias ")) 536 (princ string))))) 537 nil) 538 539(defun help-key-description (key untranslated) 540 (let ((string (key-description key))) 541 (if (or (not untranslated) 542 (and (eq (aref untranslated 0) ?\e) (not (eq (aref key 0) ?\e)))) 543 string 544 (let ((otherstring (key-description untranslated))) 545 (if (equal string otherstring) 546 string 547 (format "%s (translated from %s)" string otherstring)))))) 548 549(defun describe-key-briefly (&optional key insert untranslated) 550 "Print the name of the function KEY invokes. KEY is a string. 551If INSERT (the prefix arg) is non-nil, insert the message in the buffer. 552If non-nil, UNTRANSLATED is a vector of the untranslated events. 553It can also be a number in which case the untranslated events from 554the last key hit are used. 555 556If KEY is a menu item or a tool-bar button that is disabled, this command 557temporarily enables it to allow getting help on disabled items and buttons." 558 (interactive 559 (let ((enable-disabled-menus-and-buttons t) 560 (cursor-in-echo-area t) 561 saved-yank-menu) 562 (unwind-protect 563 (let (key) 564 ;; If yank-menu is empty, populate it temporarily, so that 565 ;; "Select and Paste" menu can generate a complete event. 566 (when (null (cdr yank-menu)) 567 (setq saved-yank-menu (copy-sequence yank-menu)) 568 (menu-bar-update-yank-menu "(any string)" nil)) 569 (setq key (read-key-sequence "Describe key (or click or menu item): ")) 570 ;; If KEY is a down-event, read and discard the 571 ;; corresponding up-event. Note that there are also 572 ;; down-events on scroll bars and mode lines: the actual 573 ;; event then is in the second element of the vector. 574 (and (vectorp key) 575 (let ((last-idx (1- (length key)))) 576 (and (eventp (aref key last-idx)) 577 (memq 'down (event-modifiers (aref key last-idx))))) 578 (read-event)) 579 (list 580 key 581 (if current-prefix-arg (prefix-numeric-value current-prefix-arg)) 582 1)) 583 ;; Put yank-menu back as it was, if we changed it. 584 (when saved-yank-menu 585 (setq yank-menu (copy-sequence saved-yank-menu)) 586 (fset 'yank-menu (cons 'keymap yank-menu)))))) 587 (if (numberp untranslated) 588 (setq untranslated (this-single-command-raw-keys))) 589 (let* ((event (if (and (symbolp (aref key 0)) 590 (> (length key) 1) 591 (consp (aref key 1))) 592 (aref key 1) 593 (aref key 0))) 594 (modifiers (event-modifiers event)) 595 (standard-output (if insert (current-buffer) t)) 596 (mouse-msg (if (or (memq 'click modifiers) (memq 'down modifiers) 597 (memq 'drag modifiers)) " at that spot" "")) 598 (defn (key-binding key t)) 599 key-desc) 600 ;; Handle the case where we faked an entry in "Select and Paste" menu. 601 (if (and (eq defn nil) 602 (stringp (aref key (1- (length key)))) 603 (eq (key-binding (substring key 0 -1)) 'yank-menu)) 604 (setq defn 'menu-bar-select-yank)) 605 ;; Don't bother user with strings from (e.g.) the select-paste menu. 606 (if (stringp (aref key (1- (length key)))) 607 (aset key (1- (length key)) "(any string)")) 608 (if (and (> (length untranslated) 0) 609 (stringp (aref untranslated (1- (length untranslated))))) 610 (aset untranslated (1- (length untranslated)) "(any string)")) 611 ;; Now describe the key, perhaps as changed. 612 (setq key-desc (help-key-description key untranslated)) 613 (if (or (null defn) (integerp defn) (equal defn 'undefined)) 614 (princ (format "%s%s is undefined" key-desc mouse-msg)) 615 (princ (format "%s%s runs the command %S" key-desc mouse-msg defn))))) 616 617(defun describe-key (&optional key untranslated up-event) 618 "Display documentation of the function invoked by KEY. 619KEY can be any kind of a key sequence; it can include keyboard events, 620mouse events, and/or menu events. When calling from a program, 621pass KEY as a string or a vector. 622 623If non-nil, UNTRANSLATED is a vector of the corresponding untranslated events. 624It can also be a number, in which case the untranslated events from 625the last key sequence entered are used. 626UP-EVENT is the up-event that was discarded by reading KEY, or nil. 627 628If KEY is a menu item or a tool-bar button that is disabled, this command 629temporarily enables it to allow getting help on disabled items and buttons." 630 (interactive 631 (let ((enable-disabled-menus-and-buttons t) 632 (cursor-in-echo-area t) 633 saved-yank-menu) 634 (unwind-protect 635 (let (key) 636 ;; If yank-menu is empty, populate it temporarily, so that 637 ;; "Select and Paste" menu can generate a complete event. 638 (when (null (cdr yank-menu)) 639 (setq saved-yank-menu (copy-sequence yank-menu)) 640 (menu-bar-update-yank-menu "(any string)" nil)) 641 (setq key (read-key-sequence "Describe key (or click or menu item): ")) 642 (list 643 key 644 (prefix-numeric-value current-prefix-arg) 645 ;; If KEY is a down-event, read and include the 646 ;; corresponding up-event. Note that there are also 647 ;; down-events on scroll bars and mode lines: the actual 648 ;; event then is in the second element of the vector. 649 (and (vectorp key) 650 (let ((last-idx (1- (length key)))) 651 (and (eventp (aref key last-idx)) 652 (memq 'down (event-modifiers (aref key last-idx))))) 653 (or (and (eventp (aref key 0)) 654 (memq 'down (event-modifiers (aref key 0))) 655 ;; However, for the C-down-mouse-2 popup 656 ;; menu, there is no subsequent up-event. In 657 ;; this case, the up-event is the next 658 ;; element in the supplied vector. 659 (= (length key) 1)) 660 (and (> (length key) 1) 661 (eventp (aref key 1)) 662 (memq 'down (event-modifiers (aref key 1))))) 663 (read-event)))) 664 ;; Put yank-menu back as it was, if we changed it. 665 (when saved-yank-menu 666 (setq yank-menu (copy-sequence saved-yank-menu)) 667 (fset 'yank-menu (cons 'keymap yank-menu)))))) 668 (if (numberp untranslated) 669 (setq untranslated (this-single-command-raw-keys))) 670 (let* ((event (aref key (if (and (symbolp (aref key 0)) 671 (> (length key) 1) 672 (consp (aref key 1))) 673 1 674 0))) 675 (modifiers (event-modifiers event)) 676 (mouse-msg (if (or (memq 'click modifiers) (memq 'down modifiers) 677 (memq 'drag modifiers)) " at that spot" "")) 678 (defn (key-binding key t)) 679 defn-up defn-up-tricky ev-type 680 mouse-1-remapped mouse-1-tricky) 681 682 ;; Handle the case where we faked an entry in "Select and Paste" menu. 683 (when (and (eq defn nil) 684 (stringp (aref key (1- (length key)))) 685 (eq (key-binding (substring key 0 -1)) 'yank-menu)) 686 (setq defn 'menu-bar-select-yank)) 687 (if (or (null defn) (integerp defn) (equal defn 'undefined)) 688 (message "%s%s is undefined" 689 (help-key-description key untranslated) mouse-msg) 690 (help-setup-xref (list #'describe-function defn) (interactive-p)) 691 ;; Don't bother user with strings from (e.g.) the select-paste menu. 692 (when (stringp (aref key (1- (length key)))) 693 (aset key (1- (length key)) "(any string)")) 694 (when (and untranslated 695 (stringp (aref untranslated (1- (length untranslated))))) 696 (aset untranslated (1- (length untranslated)) 697 "(any string)")) 698 ;; Need to do this before erasing *Help* buffer in case event 699 ;; is a mouse click in an existing *Help* buffer. 700 (when up-event 701 (setq ev-type (event-basic-type up-event)) 702 (let ((sequence (vector up-event))) 703 (when (and (eq ev-type 'mouse-1) 704 mouse-1-click-follows-link 705 (not (eq mouse-1-click-follows-link 'double)) 706 (setq mouse-1-remapped 707 (mouse-on-link-p (event-start up-event)))) 708 (setq mouse-1-tricky (and (integerp mouse-1-click-follows-link) 709 (> mouse-1-click-follows-link 0))) 710 (cond ((stringp mouse-1-remapped) 711 (setq sequence mouse-1-remapped)) 712 ((vectorp mouse-1-remapped) 713 (setcar up-event (elt mouse-1-remapped 0))) 714 (t (setcar up-event 'mouse-2)))) 715 (setq defn-up (key-binding sequence nil nil (event-start up-event))) 716 (when mouse-1-tricky 717 (setq sequence (vector up-event)) 718 (aset sequence 0 'mouse-1) 719 (setq defn-up-tricky (key-binding sequence nil nil (event-start up-event)))))) 720 (with-output-to-temp-buffer (help-buffer) 721 (princ (help-key-description key untranslated)) 722 (princ (format "\ 723%s runs the command %S 724 which is " 725 mouse-msg defn)) 726 (describe-function-1 defn) 727 (when up-event 728 (unless (or (null defn-up) 729 (integerp defn-up) 730 (equal defn-up 'undefined)) 731 (princ (format " 732 733----------------- up-event %s---------------- 734 735<%S>%s%s runs the command %S 736 which is " 737 (if mouse-1-tricky "(short click) " "") 738 ev-type mouse-msg 739 (if mouse-1-remapped 740 " is remapped to <mouse-2>\nwhich" "") 741 defn-up)) 742 (describe-function-1 defn-up)) 743 (unless (or (null defn-up-tricky) 744 (integerp defn-up-tricky) 745 (eq defn-up-tricky 'undefined)) 746 (princ (format " 747 748----------------- up-event (long click) ---------------- 749 750Pressing <%S>%s for longer than %d milli-seconds 751runs the command %S 752 which is " 753 ev-type mouse-msg 754 mouse-1-click-follows-link 755 defn-up-tricky)) 756 (describe-function-1 defn-up-tricky))) 757 (print-help-return-message))))) 758 759(defun describe-mode (&optional buffer) 760 "Display documentation of current major mode and minor modes. 761A brief summary of the minor modes comes first, followed by the 762major mode description. This is followed by detailed 763descriptions of the minor modes, each on a separate page. 764 765For this to work correctly for a minor mode, the mode's indicator 766variable \(listed in `minor-mode-alist') must also be a function 767whose documentation describes the minor mode." 768 (interactive "@") 769 (unless buffer (setq buffer (current-buffer))) 770 (help-setup-xref (list #'describe-mode buffer) 771 (interactive-p)) 772 ;; For the sake of help-do-xref and help-xref-go-back, 773 ;; don't switch buffers before calling `help-buffer'. 774 (with-output-to-temp-buffer (help-buffer) 775 (with-current-buffer buffer 776 (let (minor-modes) 777 ;; Older packages do not register in minor-mode-list but only in 778 ;; minor-mode-alist. 779 (dolist (x minor-mode-alist) 780 (setq x (car x)) 781 (unless (memq x minor-mode-list) 782 (push x minor-mode-list))) 783 ;; Find enabled minor mode we will want to mention. 784 (dolist (mode minor-mode-list) 785 ;; Document a minor mode if it is listed in minor-mode-alist, 786 ;; non-nil, and has a function definition. 787 (let ((fmode (or (get mode :minor-mode-function) mode))) 788 (and (boundp mode) (symbol-value mode) 789 (fboundp fmode) 790 (let ((pretty-minor-mode 791 (if (string-match "\\(\\(-minor\\)?-mode\\)?\\'" 792 (symbol-name fmode)) 793 (capitalize 794 (substring (symbol-name fmode) 795 0 (match-beginning 0))) 796 fmode))) 797 (push (list fmode pretty-minor-mode 798 (format-mode-line (assq mode minor-mode-alist))) 799 minor-modes))))) 800 (setq minor-modes 801 (sort minor-modes 802 (lambda (a b) (string-lessp (cadr a) (cadr b))))) 803 (when minor-modes 804 (princ "Enabled minor modes:\n") 805 (make-local-variable 'help-button-cache) 806 (with-current-buffer standard-output 807 (dolist (mode minor-modes) 808 (let ((mode-function (nth 0 mode)) 809 (pretty-minor-mode (nth 1 mode)) 810 (indicator (nth 2 mode))) 811 (add-text-properties 0 (length pretty-minor-mode) 812 '(face bold) pretty-minor-mode) 813 (save-excursion 814 (goto-char (point-max)) 815 (princ "\n\f\n") 816 (push (point-marker) help-button-cache) 817 ;; Document the minor modes fully. 818 (insert pretty-minor-mode) 819 (princ (format " minor mode (%s):\n" 820 (if (zerop (length indicator)) 821 "no indicator" 822 (format "indicator%s" 823 indicator)))) 824 (princ (documentation mode-function))) 825 (insert-button pretty-minor-mode 826 'action (car help-button-cache) 827 'follow-link t 828 'help-echo "mouse-2, RET: show full information") 829 (newline))) 830 (forward-line -1) 831 (fill-paragraph nil) 832 (forward-line 1)) 833 834 (princ "\n(Information about these minor modes follows the major mode info.)\n\n")) 835 ;; Document the major mode. 836 (let ((mode mode-name)) 837 (with-current-buffer standard-output 838 (let ((start (point))) 839 (insert (format-mode-line mode)) 840 (add-text-properties start (point) '(face bold))))) 841 (princ " mode:\n") 842 (princ (documentation major-mode))) 843 (print-help-return-message)))) 844 845 846(defun describe-minor-mode (minor-mode) 847 "Display documentation of a minor mode given as MINOR-MODE. 848MINOR-MODE can be a minor mode symbol or a minor mode indicator string 849appeared on the mode-line." 850 (interactive (list (completing-read 851 "Minor mode: " 852 (nconc 853 (describe-minor-mode-completion-table-for-symbol) 854 (describe-minor-mode-completion-table-for-indicator) 855 )))) 856 (if (symbolp minor-mode) 857 (setq minor-mode (symbol-name minor-mode))) 858 (let ((symbols (describe-minor-mode-completion-table-for-symbol)) 859 (indicators (describe-minor-mode-completion-table-for-indicator))) 860 (cond 861 ((member minor-mode symbols) 862 (describe-minor-mode-from-symbol (intern minor-mode))) 863 ((member minor-mode indicators) 864 (describe-minor-mode-from-indicator minor-mode)) 865 (t 866 (error "No such minor mode: %s" minor-mode))))) 867 868;; symbol 869(defun describe-minor-mode-completion-table-for-symbol () 870 ;; In order to list up all minor modes, minor-mode-list 871 ;; is used here instead of minor-mode-alist. 872 (delq nil (mapcar 'symbol-name minor-mode-list))) 873(defun describe-minor-mode-from-symbol (symbol) 874 "Display documentation of a minor mode given as a symbol, SYMBOL" 875 (interactive (list (intern (completing-read 876 "Minor mode symbol: " 877 (describe-minor-mode-completion-table-for-symbol))))) 878 (if (fboundp symbol) 879 (describe-function symbol) 880 (describe-variable symbol))) 881 882;; indicator 883(defun describe-minor-mode-completion-table-for-indicator () 884 (delq nil 885 (mapcar (lambda (x) 886 (let ((i (format-mode-line x))) 887 ;; remove first space if existed 888 (cond 889 ((= 0 (length i)) 890 nil) 891 ((eq (aref i 0) ?\s) 892 (substring i 1)) 893 (t 894 i)))) 895 minor-mode-alist))) 896(defun describe-minor-mode-from-indicator (indicator) 897 "Display documentation of a minor mode specified by INDICATOR. 898If you call this function interactively, you can give indicator which 899is currently activated with completion." 900 (interactive (list 901 (completing-read 902 "Minor mode indicator: " 903 (describe-minor-mode-completion-table-for-indicator)))) 904 (let ((minor-mode (lookup-minor-mode-from-indicator indicator))) 905 (if minor-mode 906 (describe-minor-mode-from-symbol minor-mode) 907 (error "Cannot find minor mode for `%s'" indicator)))) 908 909(defun lookup-minor-mode-from-indicator (indicator) 910 "Return a minor mode symbol from its indicator on the modeline." 911 ;; remove first space if existed 912 (if (and (< 0 (length indicator)) 913 (eq (aref indicator 0) ?\s)) 914 (setq indicator (substring indicator 1))) 915 (let ((minor-modes minor-mode-alist) 916 result) 917 (while minor-modes 918 (let* ((minor-mode (car (car minor-modes))) 919 (anindicator (format-mode-line 920 (car (cdr (car minor-modes)))))) 921 ;; remove first space if existed 922 (if (and (stringp anindicator) 923 (> (length anindicator) 0) 924 (eq (aref anindicator 0) ?\s)) 925 (setq anindicator (substring anindicator 1))) 926 (if (equal indicator anindicator) 927 (setq result minor-mode 928 minor-modes nil) 929 (setq minor-modes (cdr minor-modes))))) 930 result)) 931 932 933;;; Automatic resizing of temporary buffers. 934 935(defcustom temp-buffer-max-height (lambda (buffer) (/ (- (frame-height) 2) 2)) 936 "Maximum height of a window displaying a temporary buffer. 937This is effective only when Temp Buffer Resize mode is enabled. 938The value is the maximum height (in lines) which `resize-temp-buffer-window' 939will give to a window displaying a temporary buffer. 940It can also be a function to be called to choose the height for such a buffer. 941It gets one argumemt, the buffer, and should return a positive integer." 942 :type '(choice integer function) 943 :group 'help 944 :version "20.4") 945 946(define-minor-mode temp-buffer-resize-mode 947 "Toggle the mode which makes windows smaller for temporary buffers. 948With prefix argument ARG, turn the resizing of windows displaying temporary 949buffers on if ARG is positive or off otherwise. 950This makes the window the right height for its contents, but never 951more than `temp-buffer-max-height' nor less than `window-min-height'. 952This applies to `help', `apropos' and `completion' buffers, and some others." 953 :global t :group 'help 954 (if temp-buffer-resize-mode 955 ;; `help-make-xrefs' may add a `back' button and thus increase the 956 ;; text size, so `resize-temp-buffer-window' must be run *after* it. 957 (add-hook 'temp-buffer-show-hook 'resize-temp-buffer-window 'append) 958 (remove-hook 'temp-buffer-show-hook 'resize-temp-buffer-window))) 959 960(defun resize-temp-buffer-window () 961 "Resize the current window to fit its contents. 962Will not make it higher than `temp-buffer-max-height' nor smaller than 963`window-min-height'. Do nothing if it is the only window on its frame, if it 964is not as wide as the frame or if some of the window's contents are scrolled 965out of view." 966 (unless (or (one-window-p 'nomini) 967 (not (pos-visible-in-window-p (point-min))) 968 (/= (frame-width) (window-width))) 969 (fit-window-to-buffer 970 (selected-window) 971 (if (functionp temp-buffer-max-height) 972 (funcall temp-buffer-max-height (current-buffer)) 973 temp-buffer-max-height)))) 974 975 976(provide 'help) 977 978;; arch-tag: cf427352-27e9-49b7-9a6f-741ebab02423 979;;; help.el ends here 980