code.delx.au - gnu-emacs/blob - lisp/info.el

   1 ;;; info.el --- info package for Emacs.
   2
   3 ;; Copyright (C) 1985, 1986, 1992 Free Software Foundation, Inc.
   4
   5 ;; Maintainer: FSF
   6 ;; Keywords: help
   7
   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
  12 ;; the Free Software Foundation; either version 2, or (at your option)
  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
  24 ;;; Commentary:
  25
  26 ;;; Note that nowadays we expect info files to be made using makeinfo.
  27
  28 ;;; Code:
  29
  30 (defvar Info-history nil
  31   "List of info nodes user has visited.
  32 Each element of list is a list (FILENAME NODENAME BUFFERPOS).")
  33
  34 (defvar Info-enable-edit nil
  35   "*Non-nil means the \\<Info-mode-map>\\[Info-edit] command in Info can edit the current node.
  36 This is convenient if you want to write info files by hand.
  37 However, we recommend that you not do this.
  38 It is better to write a Texinfo file and generate the Info file from that,
  39 because that gives you a printed manual as well.")
  40
  41 (defvar Info-enable-active-nodes t
  42   "Non-nil allows Info to execute Lisp code associated with nodes.
  43 The Lisp code is executed when the node is selected.")
  44
  45 (defvar Info-default-directory-list nil
  46   "List of default directories to search for Info documentation files.
  47 This value is used as the default for `Info-directory-list'.  It is set
  48 in paths.el.")
  49
  50 (defvar Info-directory-list
  51   (let ((path (getenv "INFOPATH")))
  52     (if path
  53         (let ((list nil)
  54               idx)
  55           (while (> (length path) 0)
  56             (setq idx (or (string-match ":" path) (length path))
  57                   list (cons (substring path 0 idx) list)
  58                   path (substring path (min (1+ idx)
  59                                             (length path)))))
  60           (nreverse list))
  61       Info-default-directory-list))
  62   "List of directories to search for Info documentation files.
  63 nil means not yet initialized.  In this case, Info uses the environment
  64 variable INFOPATH to initialize it, or `Info-default-directory-list'
  65 if there is no INFOPATH variable in the environment.")
  66
  67 (defvar Info-current-file nil
  68   "Info file that Info is now looking at, or nil.")
  69
  70 (defvar Info-current-subfile nil
  71   "Info subfile that is actually in the *info* buffer now,
  72 or nil if current info file is not split into subfiles.")
  73
  74 (defvar Info-current-node nil
  75   "Name of node that Info is now looking at, or nil.")
  76
  77 (defvar Info-tag-table-marker (make-marker)
  78   "Marker pointing at beginning of current Info file's tag table.
  79 Marker points nowhere if file has no tag table.")
  80
  81 (defvar Info-index-alternatives nil
  82   "List of possible matches for last Info-index command.")
  83
  84 (defvar Info-suffix-list '( (""         . nil)
  85                             (".info"    . nil)
  86                             (".Z"       . "uncompress")
  87                             (".Y"       . "unyabba")
  88                             (".gz"      . "gunzip")
  89                             (".z"       . "gunzip")
  90                             (".info.Z"  . "uncompress")
  91                             (".info.Y"  . "unyabba")
  92                             (".info.gz" . "gunzip")
  93                             (".info.z"  . "gunzip"))
  94   "List of file name suffixes and associated decoding commands.
  95 Each entry should be (SUFFIX . STRING); the file is given to
  96 the command as standard input.  If STRING is nil, no decoding is done.")
  97
  98 (defun info-insert-file-contents (filename &optional visit)
  99   "Insert the contents of an info file in the current buffer.
 100 Do the right thing if the file has been compressed or zipped."
 101   (if (null (catch 'ok
 102               (mapcar
 103                (function
 104                 (lambda (x)
 105                   (let ((compressed (concat filename (car x))))
 106                     (if (file-exists-p compressed)
 107                         (progn
 108                           (insert-file-contents compressed visit)
 109                           (if (cdr x)
 110                               (let ((buffer-read-only nil))
 111                                 (shell-command-on-region
 112                                  (point-min) (point-max) (cdr x) t)))
 113                           (throw 'ok t))))))
 114                Info-suffix-list)
 115               nil))
 116       (error "Can't find %s or any compressed version of it!" filename)))
 117
 118 ;;;###autoload
 119 (defun info (&optional file)
 120   "Enter Info, the documentation browser.
 121 Optional argument FILE specifies the file to examine;
 122 the default is the top-level directory of Info.
 123
 124 In interactive use, a prefix argument directs this command
 125 to read a file name from the minibuffer."
 126   (interactive (if current-prefix-arg
 127                    (list (read-file-name "Info file name: " nil nil t))))
 128   (if file
 129       (Info-goto-node (concat "(" file ")"))
 130     (if (get-buffer "*info*")
 131         (switch-to-buffer "*info*")
 132       (Info-directory))))
 133
 134 ;; Go to an info node specified as separate filename and nodename.
 135 ;; no-going-back is non-nil if recovering from an error in this function;
 136 ;; it says do not attempt further (recursive) error recovery.
 137 (defun Info-find-node (filename nodename &optional no-going-back)
 138   ;; Convert filename to lower case if not found as specified.
 139   ;; Expand it.
 140   (if filename
 141       (let (temp temp-downcase found)
 142         (setq filename (substitute-in-file-name filename))
 143         (if (string= (downcase (file-name-nondirectory filename)) "dir")
 144             (setq found t)
 145           (let ((dirs (if (string-match "^\\./" filename)
 146                           ;; If specified name starts with `./'
 147                           ;; then just try current directory.
 148                           '("./")
 149                         Info-directory-list)))
 150             ;; Search the directory list for file FILENAME.
 151             (while (and dirs (not found))
 152               (setq temp (expand-file-name filename (car dirs)))
 153               (setq temp-downcase
 154                     (expand-file-name (downcase filename) (car dirs)))
 155               ;; Try several variants of specified name.
 156               (catch 'foundit
 157                 (mapcar
 158                  (function
 159                   (lambda (x)
 160                     (if (file-exists-p (concat temp (car x)))
 161                         (progn
 162                           (setq found temp)
 163                           (throw 'foundit nil)))
 164                     (if (file-exists-p (concat temp-downcase (car x)))
 165                         (progn
 166                           (setq found temp-downcase)
 167                           (throw 'foundit nil)))))
 168                  Info-suffix-list))
 169               (setq dirs (cdr dirs)))))
 170         (if found
 171             (setq filename found)
 172           (error "Info file %s does not exist" filename))))
 173   ;; Record the node we are leaving.
 174   (if (and Info-current-file (not no-going-back))
 175       (setq Info-history
 176             (cons (list Info-current-file Info-current-node (point))
 177                   Info-history)))
 178   ;; Go into info buffer.
 179   (switch-to-buffer "*info*")
 180   (buffer-disable-undo (current-buffer))
 181   (or (eq major-mode 'Info-mode)
 182       (Info-mode))
 183   (widen)
 184   (setq Info-current-node nil)
 185   (unwind-protect
 186       (progn
 187         ;; Switch files if necessary
 188         (or (null filename)
 189             (equal Info-current-file filename)
 190             (let ((buffer-read-only nil))
 191               (setq Info-current-file nil
 192                     Info-current-subfile nil
 193                     Info-index-alternatives nil
 194                     buffer-file-name nil)
 195               (erase-buffer)
 196               (if (eq filename t)
 197                   (Info-insert-dir)
 198                 (info-insert-file-contents filename t)
 199                 (setq default-directory (file-name-directory filename)))
 200               (set-buffer-modified-p nil)
 201               ;; See whether file has a tag table.  Record the location if yes.
 202               (set-marker Info-tag-table-marker nil)
 203               (goto-char (point-max))
 204               (forward-line -8)
 205               (or (equal nodename "*")
 206                   (not (search-forward "\^_\nEnd tag table\n" nil t))
 207                   (let (pos)
 208                     ;; We have a tag table.  Find its beginning.
 209                     ;; Is this an indirect file?
 210                     (search-backward "\nTag table:\n")
 211                     (setq pos (point))
 212                     (if (save-excursion
 213                           (forward-line 2)
 214                           (looking-at "(Indirect)\n"))
 215                         ;; It is indirect.  Copy it to another buffer
 216                         ;; and record that the tag table is in that buffer.
 217                         (save-excursion
 218                           (let ((buf (current-buffer)))
 219                             (set-buffer (get-buffer-create " *info tag table*"))
 220                             (buffer-disable-undo (current-buffer))
 221                             (setq case-fold-search t)
 222                             (erase-buffer)
 223                             (insert-buffer-substring buf)
 224                             (set-marker Info-tag-table-marker
 225                                         (match-end 0))))
 226                       (set-marker Info-tag-table-marker pos))))
 227               (setq Info-current-file
 228                     (if (eq filename t) "dir"
 229                       (file-name-sans-versions buffer-file-name)))))
 230         (if (equal nodename "*")
 231             (progn (setq Info-current-node nodename)
 232                    (Info-set-mode-line))
 233           ;; Search file for a suitable node.
 234           (let ((guesspos (point-min))
 235                 (regexp (concat "Node: *" (regexp-quote nodename) " *[,\t\n\177]")))
 236             ;; First get advice from tag table if file has one.
 237             ;; Also, if this is an indirect info file,
 238             ;; read the proper subfile into this buffer.
 239             (if (marker-position Info-tag-table-marker)
 240                 (save-excursion
 241                   (set-buffer (marker-buffer Info-tag-table-marker))
 242                   (goto-char Info-tag-table-marker)
 243                   (if (re-search-forward regexp nil t)
 244                       (progn
 245                         (setq guesspos (read (current-buffer)))
 246                         ;; If this is an indirect file,
 247                         ;; determine which file really holds this node
 248                         ;; and read it in.
 249                         (if (not (eq (current-buffer) (get-buffer "*info*")))
 250                             (setq guesspos
 251                                   (Info-read-subfile guesspos))))
 252                     (error "No such node: \"%s\"" nodename))))
 253             (goto-char (max (point-min) (- guesspos 1000)))
 254             ;; Now search from our advised position (or from beg of buffer)
 255             ;; to find the actual node.
 256             (catch 'foo
 257               (while (search-forward "\n\^_" nil t)
 258                 (forward-line 1)
 259                 (let ((beg (point)))
 260                   (forward-line 1)
 261                   (if (re-search-backward regexp beg t)
 262                       (throw 'foo t))))
 263               (error "No such node: %s" nodename)))
 264           (Info-select-node)))
 265     ;; If we did not finish finding the specified node,
 266     ;; go back to the previous one.
 267     (or Info-current-node no-going-back
 268         (let ((hist (car Info-history)))
 269           (setq Info-history (cdr Info-history))
 270           (Info-find-node (nth 0 hist) (nth 1 hist) t)
 271           (goto-char (nth 2 hist)))))
 272   (goto-char (point-min)))
 273
 274 ;; Cache the contents of the (virtual) dir file, once we have merged
 275 ;; it for the first time, so we can save time subsequently.
 276 (defvar Info-dir-contents nil)
 277
 278 ;; Cache for the directory we decided to use for the default-directory
 279 ;; of the merged dir text.
 280 (defvar Info-dir-contents-directory nil)
 281
 282 ;; Record the file attributes of all the files from which we
 283 ;; constructed Info-dir-contents.
 284 (defvar Info-dir-file-attributes nil)
 285
 286 ;; Construct the Info directory node by merging the files named `dir'
 287 ;; from various directories.  Set the *info* buffer's
 288 ;; default-directory to the first directory we actually get any text
 289 ;; from.
 290 (defun Info-insert-dir ()
 291   (if (and Info-dir-contents Info-dir-file-attributes
 292            ;; Verify that none of the files we used has changed
 293            ;; since we used it.
 294            (eval (cons 'and
 295                        (mapcar '(lambda (elt)
 296                                   (equal (cdr elt)
 297                                          (file-attributes (car elt))))
 298                                Info-dir-file-attributes))))
 299       (insert Info-dir-contents)
 300     (let ((dirs Info-directory-list)
 301           buffers buffer others nodes dirs-done)
 302
 303       ;; Search the directory list for the directory file.
 304       (while dirs
 305         (or (member (file-truename (expand-file-name (car dirs))) dirs-done)
 306             (member (directory-file-name (file-truename (expand-file-name (car dirs))))
 307                     dirs-done)
 308             ;; Try several variants of specified name.
 309             ;; Try upcasing, appending `.info', or both.
 310             (let* (temp
 311                    (buffer
 312                     (cond
 313                      ((progn (setq temp (expand-file-name "DIR" (car dirs)))
 314                              (file-exists-p temp))
 315                       (find-file-noselect temp))
 316                      ((progn (setq temp (expand-file-name "dir" (car dirs)))
 317                              (file-exists-p temp))
 318                       (find-file-noselect temp))
 319                      ((progn (setq temp (expand-file-name "DIR.INFO" (car dirs)))
 320                              (file-exists-p temp))
 321                       (find-file-noselect temp))
 322                      ((progn (setq temp (expand-file-name "dir.info" (car dirs)))
 323                              (file-exists-p temp))
 324                       (find-file-noselect temp)))))
 325               (setq dirs-done
 326                     (cons (file-truename (expand-file-name (car dirs)))
 327                           (cons (directory-file-name
 328                                  (file-truename (expand-file-name (car dirs))))
 329                                 dirs-done)))
 330               (if buffer (setq buffers (cons buffer buffers)
 331                                Info-dir-file-attributes
 332                                (cons (cons (buffer-file-name buffer)
 333                                            (file-attributes (buffer-file-name buffer)))
 334                                      Info-dir-file-attributes)))))
 335         (setq dirs (cdr dirs)))
 336
 337       ;; Distinguish the dir file that comes with Emacs from all the
 338       ;; others.  Yes, that is really what this is supposed to do.
 339       ;; If it doesn't work, fix it.
 340       (setq buffer (car buffers)
 341             others (cdr buffers))
 342
 343       ;; Insert the entire original dir file as a start; use its
 344       ;; default directory as the default directory for the whole
 345       ;; concatenation.
 346       (insert-buffer buffer)
 347       (setq Info-dir-contents-directory (save-excursion
 348                                           (set-buffer buffer)
 349                                           default-directory))
 350
 351       ;; Look at each of the other buffers one by one.
 352       (while others
 353         (let ((other (car others)))
 354           ;; In each, find all the menus.
 355           (save-excursion
 356             (set-buffer other)
 357             (goto-char (point-min))
 358             ;; Find each menu, and add an elt to NODES for it.
 359             (while (re-search-forward "^\\* Menu:" nil t)
 360               (let (beg nodename end)
 361                 (forward-line 1)
 362                 (setq beg (point))
 363                 (search-backward "\n\1f")
 364                 (search-forward "Node: ")
 365                 (setq nodename (Info-following-node-name))
 366                 (search-forward "\n\1f" nil 'move)
 367                 (beginning-of-line)
 368                 (setq end (point))
 369                 (setq nodes (cons (list nodename other beg end) nodes))))))
 370         (setq others (cdr others)))
 371       ;; Add to the main menu a menu item for each other node.
 372       (re-search-forward "^\\* Menu:")
 373       (forward-line 1)
 374       (let ((menu-items '("top"))
 375             (nodes nodes)
 376             (case-fold-search t)
 377             (end (save-excursion (search-forward "\1f" nil t) (point))))
 378         (while nodes
 379           (let ((nodename (car (car nodes))))
 380             (or (member (downcase nodename) menu-items)
 381                 (re-search-forward (concat "^\\* " (regexp-quote nodename) ":")
 382                                    end t)
 383                 (progn
 384                   (insert "* " nodename "\n")
 385                   (setq menu-items (cons nodename menu-items)))))
 386           (setq nodes (cdr nodes))))
 387       ;; Now take each node of each of the other buffers
 388       ;; and merge it into the main buffer.
 389       (while nodes
 390         (let ((nodename (car (car nodes))))
 391           (goto-char (point-min))
 392           ;; Find the like-named node in the main buffer.
 393           (if (re-search-forward (concat "\n\1f.*\n.*Node: "
 394                                          (regexp-quote nodename)
 395                                          "[,\n\t]")
 396                                  nil t)
 397               (progn
 398                 (search-forward "\n\1f" nil 'move)
 399                 (beginning-of-line))
 400             ;; If none exists, add one.
 401             (goto-char (point-max))
 402             (insert "\1f\nFile: dir\tnode: " nodename "\n\n* Menu:\n\n"))
 403           ;; Merge the text from the other buffer's menu
 404           ;; into the menu in the like-named node in the main buffer.
 405           (apply 'insert-buffer-substring (cdr (car nodes)))
 406           (insert "\n"))
 407         (setq nodes (cdr nodes)))
 408       ;; Kill all the buffers we just made.
 409       (while buffers
 410         (kill-buffer (car buffers))
 411         (setq buffers (cdr buffers))))
 412     (setq Info-dir-contents (buffer-string)))
 413   (setq default-directory Info-dir-contents-directory))
 414
 415 (defun Info-read-subfile (nodepos)
 416   (set-buffer (marker-buffer Info-tag-table-marker))
 417   (goto-char (point-min))
 418   (search-forward "\n\^_")
 419   (let (lastfilepos
 420         lastfilename)
 421     (forward-line 2)
 422     (catch 'foo
 423       (while (not (looking-at "\^_"))
 424         (if (not (eolp))
 425             (let ((beg (point))
 426                   thisfilepos thisfilename)
 427               (search-forward ": ")
 428               (setq thisfilename  (buffer-substring beg (- (point) 2)))
 429               (setq thisfilepos (read (current-buffer)))
 430               ;; read in version 19 stops at the end of number.
 431               ;; Advance to the next line.
 432               (forward-line 1)
 433               (if (> thisfilepos nodepos)
 434                   (throw 'foo t))
 435               (setq lastfilename thisfilename)
 436               (setq lastfilepos thisfilepos))
 437           (forward-line 1))))
 438     (set-buffer (get-buffer "*info*"))
 439     (or (equal Info-current-subfile lastfilename)
 440         (let ((buffer-read-only nil))
 441           (setq buffer-file-name nil)
 442           (widen)
 443           (erase-buffer)
 444           (info-insert-file-contents lastfilename)
 445           (set-buffer-modified-p nil)
 446           (setq Info-current-subfile lastfilename)))
 447     (goto-char (point-min))
 448     (search-forward "\n\^_")
 449     (+ (- nodepos lastfilepos) (point))))
 450
 451 ;; Select the info node that point is in.
 452 (defun Info-select-node ()
 453   (save-excursion
 454    ;; Find beginning of node.
 455    (search-backward "\n\^_")
 456    (forward-line 2)
 457    ;; Get nodename spelled as it is in the node.
 458    (re-search-forward "Node:[ \t]*")
 459    (setq Info-current-node
 460          (buffer-substring (point)
 461                            (progn
 462                             (skip-chars-forward "^,\t\n")
 463                             (point))))
 464    (Info-set-mode-line)
 465    ;; Find the end of it, and narrow.
 466    (beginning-of-line)
 467    (let (active-expression)
 468      (narrow-to-region (point)
 469                        (if (re-search-forward "\n[\^_\f]" nil t)
 470                            (prog1
 471                             (1- (point))
 472                             (if (looking-at "[\n\^_\f]*execute: ")
 473                                 (progn
 474                                   (goto-char (match-end 0))
 475                                   (setq active-expression
 476                                         (read (current-buffer))))))
 477                          (point-max)))
 478      (if Info-enable-active-nodes (eval active-expression)))))
 479
 480 (defun Info-set-mode-line ()
 481   (setq mode-line-buffer-identification
 482         (concat
 483          "Info:  ("
 484          (if Info-current-file
 485              (file-name-nondirectory Info-current-file)
 486            "")
 487          ")"
 488          (or Info-current-node ""))))
 489 \f
 490 ;; Go to an info node specified with a filename-and-nodename string
 491 ;; of the sort that is found in pointers in nodes.
 492
 493 (defun Info-goto-node (nodename)
 494   "Go to info node named NAME.  Give just NODENAME or (FILENAME)NODENAME."
 495   (interactive "sGoto node: ")
 496   (let (filename)
 497     (string-match "\\s *\\((\\s *\\([^\t)]*\\)\\s *)\\s *\\|\\)\\(.*\\)"
 498                   nodename)
 499     (setq filename (if (= (match-beginning 1) (match-end 1))
 500                        ""
 501                      (substring nodename (match-beginning 2) (match-end 2)))
 502           nodename (substring nodename (match-beginning 3) (match-end 3)))
 503     (let ((trim (string-match "\\s *\\'" filename)))
 504       (if trim (setq filename (substring filename 0 trim))))
 505     (let ((trim (string-match "\\s *\\'" nodename)))
 506       (if trim (setq nodename (substring nodename 0 trim))))
 507     (Info-find-node (if (equal filename "") nil filename)
 508                     (if (equal nodename "") "Top" nodename))))
 509 \f
 510 (defun Info-restore-point (hl)
 511   "If this node has been visited, restore the point value when we left."
 512   (if hl
 513       (if (and (equal (nth 0 (car hl)) Info-current-file)
 514                (equal (nth 1 (car hl)) Info-current-node))
 515           (goto-char (nth 2 (car hl)))
 516         (Info-restore-point (cdr hl)))))
 517 \f
 518 (defvar Info-last-search nil
 519   "Default regexp for \\<Info-mode-map>\\[Info-search] command to search for.")
 520
 521 (defun Info-search (regexp)
 522   "Search for REGEXP, starting from point, and select node it's found in."
 523   (interactive "sSearch (regexp): ")
 524   (if (equal regexp "")
 525       (setq regexp Info-last-search)
 526     (setq Info-last-search regexp))
 527   (let ((found ()) current
 528         (onode Info-current-node)
 529         (ofile Info-current-file)
 530         (opoint (point))
 531         (osubfile Info-current-subfile))
 532     (save-excursion
 533       (save-restriction
 534         (widen)
 535         (if (null Info-current-subfile)
 536             (progn (re-search-forward regexp) (setq found (point)))
 537           (condition-case err
 538               (progn (re-search-forward regexp) (setq found (point)))
 539             (search-failed nil)))))
 540     (if (not found) ;can only happen in subfile case -- else would have erred
 541         (unwind-protect
 542             (let ((list ()))
 543               (set-buffer (marker-buffer Info-tag-table-marker))
 544               (goto-char (point-min))
 545               (search-forward "\n\^_\nIndirect:")
 546               (save-restriction
 547                 (narrow-to-region (point)
 548                                   (progn (search-forward "\n\^_")
 549                                          (1- (point))))
 550                 (goto-char (point-min))
 551                 (search-forward (concat "\n" osubfile ": "))
 552                 (beginning-of-line)
 553                 (while (not (eobp))
 554                   (re-search-forward "\\(^.*\\): [0-9]+$")
 555                   (goto-char (+ (match-end 1) 2))
 556                   (setq list (cons (cons (read (current-buffer))
 557                                          (buffer-substring (match-beginning 1)
 558                                                            (match-end 1)))
 559                                    list))
 560                   (goto-char (1+ (match-end 0))))
 561                 (setq list (nreverse list)
 562                       current (car (car list))
 563                       list (cdr list)))
 564               (while list
 565                 (message "Searching subfile %s..." (cdr (car list)))
 566                 (Info-read-subfile (car (car list)))
 567                 (setq list (cdr list))
 568                 (goto-char (point-min))
 569                 (if (re-search-forward regexp nil t)
 570                     (setq found (point) list ())))
 571               (if found
 572                   (message "")
 573                 (signal 'search-failed (list regexp))))
 574           (if (not found)
 575               (progn (Info-read-subfile opoint)
 576                      (goto-char opoint)
 577                      (Info-select-node)))))
 578     (widen)
 579     (goto-char found)
 580     (Info-select-node)
 581     (or (and (equal onode Info-current-node)
 582              (equal ofile Info-current-file))
 583         (setq Info-history (cons (list ofile onode opoint)
 584                                  Info-history)))))
 585 \f
 586 ;; Extract the value of the node-pointer named NAME.
 587 ;; If there is none, use ERRORNAME in the error message;
 588 ;; if ERRORNAME is nil, just return nil.
 589 (defun Info-extract-pointer (name &optional errorname)
 590   (save-excursion
 591    (goto-char (point-min))
 592    (forward-line 1)
 593    (if (re-search-backward (concat name ":") nil t)
 594        (progn
 595          (goto-char (match-end 0))
 596          (Info-following-node-name))
 597      (if (eq errorname t)
 598          nil
 599        (error (concat "Node has no " (capitalize (or errorname name))))))))
 600
 601 ;; Return the node name in the buffer following point.
 602 ;; ALLOWEDCHARS, if non-nil, goes within [...] to make a regexp
 603 ;; saying which chas may appear in the node name.
 604 (defun Info-following-node-name (&optional allowedchars)
 605   (skip-chars-forward " \t")
 606   (buffer-substring
 607    (point)
 608    (progn
 609      (while (looking-at (concat "[" (or allowedchars "^,\t\n") "]"))
 610        (skip-chars-forward (concat (or allowedchars "^,\t\n") "("))
 611        (if (looking-at "(")
 612            (skip-chars-forward "^)")))
 613      (skip-chars-backward " ")
 614      (point))))
 615
 616 (defun Info-next ()
 617   "Go to the next node of this node."
 618   (interactive)
 619   (Info-goto-node (Info-extract-pointer "next")))
 620
 621 (defun Info-prev ()
 622   "Go to the previous node of this node."
 623   (interactive)
 624   (Info-goto-node (Info-extract-pointer "prev[ious]*" "previous")))
 625
 626 (defun Info-up ()
 627   "Go to the superior node of this node."
 628   (interactive)
 629   (Info-goto-node (Info-extract-pointer "up"))
 630   (Info-restore-point Info-history))
 631
 632 (defun Info-last ()
 633   "Go back to the last node visited."
 634   (interactive)
 635   (or Info-history
 636       (error "This is the first Info node you looked at"))
 637   (let (filename nodename opoint)
 638     (setq filename (car (car Info-history)))
 639     (setq nodename (car (cdr (car Info-history))))
 640     (setq opoint (car (cdr (cdr (car Info-history)))))
 641     (setq Info-history (cdr Info-history))
 642     (Info-find-node filename nodename)
 643     (setq Info-history (cdr Info-history))
 644     (goto-char opoint)))
 645
 646 (defun Info-directory ()
 647   "Go to the Info directory node."
 648   (interactive)
 649   (Info-find-node "dir" "top"))
 650 \f
 651 (defun Info-follow-reference (footnotename)
 652   "Follow cross reference named NAME to the node it refers to.
 653 NAME may be an abbreviation of the reference name."
 654   (interactive
 655    (let ((completion-ignore-case t)
 656          completions default (start-point (point)) str i)
 657      (save-excursion
 658        (goto-char (point-min))
 659        (while (re-search-forward "\\*note[ \n\t]*\\([^:]*\\):" nil t)
 660          (setq str (buffer-substring
 661                     (match-beginning 1)
 662                     (1- (point))))
 663          ;; See if this one should be the default.
 664          (and (null default)
 665               (< (match-beginning 0) start-point)
 666               (<= start-point (point))
 667               (setq default t))
 668          (setq i 0)
 669          (while (setq i (string-match "[ \n\t]+" str i))
 670            (setq str (concat (substring str 0 i) " "
 671                              (substring str (match-end 0))))
 672            (setq i (1+ i)))
 673          ;; Record as a completion and perhaps as default.
 674          (if (eq default t) (setq default str))
 675          (setq completions
 676                (cons (cons str nil)
 677                      completions))))
 678      (if completions
 679          (let ((input (completing-read (if default
 680                                            (concat "Follow reference named: ("
 681                                                    default ") ")
 682                                          "Follow reference named: ")
 683                                        completions nil t)))
 684            (list (if (equal input "")
 685                      default input)))
 686        (error "No cross-references in this node"))))
 687   (let (target beg i (str (concat "\\*note " footnotename)))
 688     (while (setq i (string-match " " str i))
 689       (setq str (concat (substring str 0 i) "[ \t\n]+" (substring str (1+ i))))
 690       (setq i (+ i 6)))
 691     (save-excursion
 692       (goto-char (point-min))
 693       (or (re-search-forward str nil t)
 694           (error "No cross-reference named %s" footnotename))
 695       (goto-char (+ (match-beginning 0) 5))
 696       (setq target
 697             (Info-extract-menu-node-name "Bad format cross reference" t)))
 698     (while (setq i (string-match "[ \t\n]+" target i))
 699       (setq target (concat (substring target 0 i) " "
 700                            (substring target (match-end 0))))
 701       (setq i (+ i 1)))
 702     (Info-goto-node target)))
 703
 704 (defun Info-extract-menu-node-name (&optional errmessage multi-line)
 705   (skip-chars-forward " \t\n")
 706   (let ((beg (point))
 707         str i)
 708     (skip-chars-forward "^:")
 709     (forward-char 1)
 710     (setq str
 711           (if (looking-at ":")
 712               (buffer-substring beg (1- (point)))
 713             (skip-chars-forward " \t\n")
 714             (Info-following-node-name (if multi-line "^.,\t" "^.,\t\n"))))
 715     (while (setq i (string-match "\n" str i))
 716       (aset str i ?\ ))
 717     str))
 718
 719 ;; No one calls this and Info-menu-item doesn't exist.
 720 ;;(defun Info-menu-item-sequence (list)
 721 ;;  (while list
 722 ;;    (Info-menu-item (car list))
 723 ;;    (setq list (cdr list))))
 724
 725 (defun Info-menu (menu-item)
 726   "Go to node for menu item named (or abbreviated) NAME.
 727 Completion is allowed, and the menu item point is on is the default."
 728   (interactive
 729    (let ((completions '())
 730          ;; If point is within a menu item, use that item as the default
 731          (default nil)
 732          (p (point))
 733          (last nil))
 734      (save-excursion
 735        (goto-char (point-min))
 736        (if (not (search-forward "\n* menu:" nil t))
 737            (error "No menu in this node"))
 738        (while (re-search-forward
 739                 "\n\\* \\([^:\t\n]*\\):" nil t)
 740          (if (and (null default)
 741                   (prog1 (if last (< last p) nil)
 742                     (setq last (match-beginning 0)))
 743                   (<= p last))
 744              (setq default (car (car completions))))
 745          (setq completions (cons (cons (buffer-substring
 746                                          (match-beginning 1)
 747                                          (match-end 1))
 748                                        (match-beginning 1))
 749                                  completions)))
 750        (if (and (null default) last
 751                 (< last p)
 752                 (<= p (progn (end-of-line) (point))))
 753            (setq default (car (car completions)))))
 754      (let ((item nil))
 755        (while (null item)
 756          (setq item (let ((completion-ignore-case t))
 757                       (completing-read (if default
 758                                            (format "Menu item (default %s): "
 759                                                    default)
 760                                            "Menu item: ")
 761                                        completions nil t)))
 762          ;; we rely on the fact that completing-read accepts an input
 763          ;; of "" even when the require-match argument is true and ""
 764          ;; is not a valid possibility
 765          (if (string= item "")
 766              (if default
 767                  (setq item default)
 768                  ;; ask again
 769                  (setq item nil))))
 770        (list item))))
 771   ;; there is a problem here in that if several menu items have the same
 772   ;; name you can only go to the node of the first with this command.
 773   (Info-goto-node (Info-extract-menu-item menu-item)))
 774
 775 (defun Info-extract-menu-item (menu-item)
 776   (setq menu-item (regexp-quote menu-item))
 777   (save-excursion
 778     (goto-char (point-min))
 779     (or (search-forward "\n* menu:" nil t)
 780         (error "No menu in this node"))
 781     (or (re-search-forward (concat "\n* " menu-item ":") nil t)
 782         (re-search-forward (concat "\n* " menu-item) nil t)
 783         (error "No such item in menu"))
 784     (beginning-of-line)
 785     (forward-char 2)
 786     (Info-extract-menu-node-name)))
 787
 788 ;; If COUNT is nil, use the last item in the menu.
 789 (defun Info-extract-menu-counting (count)
 790   (save-excursion
 791     (goto-char (point-min))
 792     (or (search-forward "\n* menu:" nil t)
 793         (error "No menu in this node"))
 794     (if count
 795         (or (search-forward "\n* " nil t count)
 796             (error "Too few items in menu"))
 797       (while (search-forward "\n* " nil t)
 798         nil))
 799     (Info-extract-menu-node-name)))
 800
 801 (defun Info-nth-menu-item ()
 802   "Go to the node of the Nth menu item.
 803 N is the digit argument used to invoke this command."
 804   (interactive)
 805   (Info-goto-node
 806    (Info-extract-menu-counting
 807     (- (aref (this-command-keys) (1- (length (this-command-keys)))) ?0))))
 808
 809 (defun Info-top-node ()
 810   "Go to the Top node of this file."
 811   (interactive)
 812   (Info-goto-node "Top"))
 813
 814 (defun Info-final-node ()
 815   "Go to the final node in this file."
 816   (interactive)
 817   (Info-goto-node "Top")
 818   (let (Info-history)
 819     ;; Go to the last node in the menu of Top.
 820     (Info-goto-node (Info-extract-menu-counting nil))
 821     ;; If the last node in the menu is not last in pointer structure,
 822     ;; move forward until we can't go any farther.
 823     (while (Info-forward-node t t) nil)
 824     ;; Then keep moving down to last subnode, unless we reach an index.
 825     (while (and (not (string-match "\\<index\\>" Info-current-node))
 826                 (save-excursion (search-forward "\n* Menu:" nil t)))
 827       (Info-goto-node (Info-extract-menu-counting nil)))))
 828
 829 (defun Info-forward-node (&optional not-down no-error)
 830   "Go forward one node, considering all nodes as forming one sequence."
 831   (interactive)
 832   (goto-char (point-min))
 833   (forward-line 1)
 834   ;; three possibilities, in order of priority:
 835   ;;     1. next node is in a menu in this node (but not in an index)
 836   ;;     2. next node is next at same level
 837   ;;     3. next node is up and next
 838   (cond ((and (not not-down)
 839               (save-excursion (search-forward "\n* menu:" nil t))
 840               (not (string-match "\\<index\\>" Info-current-node)))
 841          (Info-goto-node (Info-extract-menu-counting 1))
 842          t)
 843         ((save-excursion (search-backward "next:" nil t))
 844          (Info-next)
 845          t)
 846         ((and (save-excursion (search-backward "up:" nil t))
 847               (not (equal (downcase (Info-extract-pointer "up")) "top")))
 848          (let ((old-node Info-current-node))
 849            (Info-up)
 850            (let (Info-history success)
 851              (unwind-protect
 852                  (setq success (Info-forward-node t no-error))
 853                (or success (Info-goto-node old-node))))))
 854         (no-error nil)
 855         (t (error "No pointer forward from this node"))))
 856
 857 (defun Info-backward-node ()
 858   "Go backward one node, considering all nodes as forming one sequence."
 859   (interactive)
 860   (let ((prevnode (Info-extract-pointer "prev[ious]*" t))
 861         (upnode (Info-extract-pointer "up" t)))
 862     (cond ((and upnode (string-match "(" upnode))
 863            (error "First node in file"))
 864           ((and upnode (or (null prevnode)
 865                            (equal (downcase prevnode) (downcase upnode))))
 866            (Info-up))
 867           (prevnode
 868            ;; If we move back at the same level,
 869            ;; go down to find the last subnode*.
 870            (Info-prev)
 871            (let (Info-history)
 872              (while (and (not (string-match "\\<index\\>" Info-current-node))
 873                          (save-excursion (search-forward "\n* Menu:" nil t)))
 874                (Info-goto-node (Info-extract-menu-counting nil)))))
 875           (t
 876            (error "No pointer backward from this node")))))
 877
 878 (defun Info-exit ()
 879   "Exit Info by selecting some other buffer."
 880   (interactive)
 881   (switch-to-buffer (prog1 (other-buffer (current-buffer))
 882                            (bury-buffer (current-buffer)))))
 883
 884 (defun Info-next-menu-item ()
 885   (interactive)
 886   (save-excursion
 887     (forward-line -1)
 888     (search-forward "\n* menu:" nil t)
 889     (or (search-forward "\n* " nil t)
 890         (error "No more items in menu"))
 891     (Info-goto-node (Info-extract-menu-node-name))))
 892
 893 (defun Info-last-menu-item ()
 894   (interactive)
 895   (save-excursion
 896     (forward-line 1)
 897     (search-backward "\n* menu:" nil t)
 898     (or (search-backward "\n* " nil t)
 899         (error "No previous items in menu"))
 900     (Info-goto-node (Info-extract-menu-node-name))))
 901
 902 (defmacro no-error (&rest body)
 903   (list 'condition-case nil (cons 'progn (append body '(t))) '(error nil)))
 904
 905 (defun Info-next-preorder ()
 906   "Go to the next node, popping up a level if there is none."
 907   (interactive)
 908   (cond ((no-error (Info-next-menu-item))       )
 909         ((no-error (Info-up))                   (forward-line 1))
 910         (t                                      (error "No more nodes"))))
 911
 912 (defun Info-last-preorder ()
 913   "Go to the last node, popping up a level if there is none."
 914   (interactive)
 915   (cond ((no-error (Info-last-menu-item))       )
 916         ((no-error (Info-up))                   (forward-line -1))
 917         (t                                      (error "No previous nodes"))))
 918
 919 (defun Info-scroll-up ()
 920   "Read the next screen.  If end of buffer is visible, go to next entry."
 921   (interactive)
 922   (if (pos-visible-in-window-p (point-max))
 923       (Info-next-preorder)
 924       (scroll-up))
 925   )
 926
 927 (defun Info-scroll-down ()
 928   "Read the previous screen.  If start of buffer is visible, go to last entry."
 929   (interactive)
 930   (if (pos-visible-in-window-p (point-min))
 931       (Info-last-preorder)
 932       (scroll-down))
 933   )
 934
 935 (defun Info-index (topic)
 936   "Look up a string in the index for this file.
 937 The index is defined as the first node in the top-level menu whose
 938 name contains the word \"Index\", plus any immediately following
 939 nodes whose names also contain the word \"Index\".
 940 If there are no exact matches to the specified topic, this chooses
 941 the first match which is a case-insensitive substring of a topic.
 942 Use the `,' command to see the other matches.
 943 Give a blank topic name to go to the Index node itself."
 944   (interactive "sIndex topic: ")
 945   (let ((orignode Info-current-node)
 946         (rnode nil)
 947         (pattern (format "\n\\* \\([^\n:]*%s[^\n:]*\\):[ \t]*\\([^.\n]*\\)\\.[ t]*\\([0-9]*\\)"
 948                          (regexp-quote topic)))
 949         node)
 950     (Info-goto-node "Top")
 951     (or (search-forward "\n* menu:" nil t)
 952         (error "No index"))
 953     (or (re-search-forward "\n\\* \\(.*\\<Index\\>\\)" nil t)
 954         (error "No index"))
 955     (goto-char (match-beginning 1))
 956     (let ((Info-keeping-history nil))
 957       (Info-goto-node (Info-extract-menu-node-name)))
 958     (or (equal topic "")
 959         (let ((matches nil)
 960               (exact nil)
 961               (Info-keeping-history nil)
 962               found)
 963           (while
 964               (progn
 965                 (goto-char (point-min))
 966                 (while (re-search-forward pattern nil t)
 967                   (setq matches
 968                         (cons (list (buffer-substring (match-beginning 1)
 969                                                       (match-end 1))
 970                                     (buffer-substring (match-beginning 2)
 971                                                       (match-end 2))
 972                                     Info-current-node
 973                                     (string-to-int (concat "0"
 974                                                            (buffer-substring
 975                                                             (match-beginning 3)
 976                                                             (match-end 3)))))
 977                               matches)))
 978                 (and (setq node (Info-extract-pointer "next" t))
 979                      (string-match "\\<Index\\>" node)))
 980             (Info-goto-node node))
 981           (or matches
 982               (progn
 983                 (Info-last)
 984                 (error "No \"%s\" in index" topic)))
 985           ;; Here it is a feature that assoc is case-sensitive.
 986           (while (setq found (assoc topic matches))
 987             (setq exact (cons found exact)
 988                   matches (delq found matches)))
 989           (setq Info-index-alternatives (nconc exact (nreverse matches)))
 990           (Info-index-next 0)))))
 991
 992 (defun Info-index-next (num)
 993   "Go to the next matching index item from the last `i' command."
 994   (interactive "p")
 995   (or Info-index-alternatives
 996       (error "No previous `i' command in this file"))
 997   (while (< num 0)
 998     (setq num (+ num (length Info-index-alternatives))))
 999   (while (> num 0)
1000     (setq Info-index-alternatives
1001           (nconc (cdr Info-index-alternatives)
1002                  (list (car Info-index-alternatives)))
1003           num (1- num)))
1004   (Info-goto-node (nth 1 (car Info-index-alternatives)))
1005   (if (> (nth 3 (car Info-index-alternatives)) 0)
1006       (forward-line (nth 3 (car Info-index-alternatives)))
1007     (forward-line 3)  ; don't search in headers
1008     (let ((name (car (car Info-index-alternatives))))
1009       (if (or (re-search-forward (format
1010                                   "\\(Function\\|Command\\): %s\\( \\|$\\)"
1011                                   (regexp-quote name)) nil t)
1012               (search-forward (format "`%s'" name) nil t)
1013               (and (string-match "\\`.*\\( (.*)\\)\\'" name)
1014                    (search-forward
1015                     (format "`%s'" (substring name 0 (match-beginning 1)))
1016                     nil t))
1017               (search-forward name nil t))
1018           (beginning-of-line)
1019         (goto-char (point-min)))))
1020   (message "Found \"%s\" in %s.  %s"
1021            (car (car Info-index-alternatives))
1022            (nth 2 (car Info-index-alternatives))
1023            (if (cdr Info-index-alternatives)
1024                "(Press `,' for more)"
1025              "(Only match)")))
1026
1027 (defun Info-undefined ()
1028   "Make command be undefined in Info."
1029   (interactive)
1030   (ding))
1031
1032 (defun Info-help ()
1033   "Enter the Info tutorial."
1034   (interactive)
1035   (delete-other-windows)
1036   (Info-find-node "info"
1037                   (if (< (window-height) 23)
1038                       "Help-Small-Screen"
1039                     "Help")))
1040
1041 (defun Info-summary ()
1042   "Display a brief summary of all Info commands."
1043   (interactive)
1044   (save-window-excursion
1045     (switch-to-buffer "*Help*")
1046     (erase-buffer)
1047     (insert (documentation 'Info-mode))
1048     (goto-char (point-min))
1049     (let (ch flag)
1050       (while (progn (setq flag (not (pos-visible-in-window-p (point-max))))
1051                     (message (if flag "Type Space to see more"
1052                                "Type Space to return to Info"))
1053                     (if (not (eq ?\  (setq ch (read-event))))
1054                         (progn (setq unread-command-events (list ch)) nil)
1055                       flag))
1056         (scroll-up)))))
1057 \f
1058 (defun Info-get-token (pos start all &optional errorstring)
1059   "Return the token around POS,
1060 POS must be somewhere inside the token
1061 START is a regular expression which will match the
1062     beginning of the tokens delimited string
1063 ALL is a regular expression with a single
1064     parenthized subpattern which is the token to be
1065     returned. E.g. '{\(.*\)}' would return any string
1066     enclosed in braces around POS.
1067 SIG optional fourth argument, controls action on no match
1068     nil: return nil
1069     t: beep
1070     a string: signal an error, using that string."
1071   (save-excursion
1072     (goto-char pos)
1073     (re-search-backward start (max (point-min) (- pos 200)) 'yes)
1074     (let (found)
1075       (while (and (re-search-forward all (min (point-max) (+ pos 200)) 'yes)
1076                   (not (setq found (and (<= (match-beginning 0) pos)
1077                                         (> (match-end 0) pos))))))
1078       (if (and found (<= (match-beginning 0) pos)
1079                (> (match-end 0) pos))
1080           (buffer-substring (match-beginning 1) (match-end 1))
1081         (cond ((null errorstring)
1082                nil)
1083               ((eq errorstring t)
1084                (beep)
1085                nil)
1086               (t
1087                (error "No %s around position %d" errorstring pos)))))))
1088
1089 (defun Info-follow-nearest-node (click)
1090   "\\<Info-mode-map>Follow a node reference near point.
1091 Like \\[Info-menu], \\[Info-follow-reference], \\[Info-next], \\[Info-prev] or \\[Info-up] command, depending on where you click.
1092 At end of the node's text, moves to the next node."
1093   (interactive "e")
1094   (let* ((start (event-start click))
1095          (window (car start))
1096          (pos (car (cdr start))))
1097     (select-window window)
1098     (goto-char pos))
1099   (let (node)
1100     (cond
1101      ((setq node (Info-get-token (point) "\\*note[ \n]" "\\*note[ \n]\\([^:]*\\):"))
1102       (Info-follow-reference node))
1103      ((setq node (Info-get-token (point) "\\* " "\\* \\([^:]*\\)::"))
1104       (Info-goto-node node))
1105      ((setq node (Info-get-token (point) "\\* " "\\* \\([^:]*\\):"))
1106       (Info-menu node))
1107      ((setq node (Info-get-token (point) "Up: " "Up: \\([^,\n\t]*\\)"))
1108       (Info-goto-node node))
1109      ((setq node (Info-get-token (point) "Next: " "Next: \\([^,\n\t]*\\)"))
1110       (Info-goto-node node))
1111      ((setq node (Info-get-token (point) "File: " "File: \\([^,\n\t]*\\)"))
1112       (Info-goto-node "Top"))
1113      ((setq node (Info-get-token (point) "Prev: " "Prev: \\([^,\n\t]*\\)"))
1114       (Info-goto-node node))
1115      ((save-excursion (forward-line 1) (eobp))
1116       (Info-next)))
1117     ))
1118 \f
1119 (defvar Info-mode-map nil
1120   "Keymap containing Info commands.")
1121 (if Info-mode-map
1122     nil
1123   (setq Info-mode-map (make-keymap))
1124   (suppress-keymap Info-mode-map)
1125   (define-key Info-mode-map "." 'beginning-of-buffer)
1126   (define-key Info-mode-map " " 'Info-scroll-up)
1127   (define-key Info-mode-map "\C-m" 'Info-next-preorder)
1128   (define-key Info-mode-map "1" 'Info-nth-menu-item)
1129   (define-key Info-mode-map "2" 'Info-nth-menu-item)
1130   (define-key Info-mode-map "3" 'Info-nth-menu-item)
1131   (define-key Info-mode-map "4" 'Info-nth-menu-item)
1132   (define-key Info-mode-map "5" 'Info-nth-menu-item)
1133   (define-key Info-mode-map "6" 'Info-nth-menu-item)
1134   (define-key Info-mode-map "7" 'Info-nth-menu-item)
1135   (define-key Info-mode-map "8" 'Info-nth-menu-item)
1136   (define-key Info-mode-map "9" 'Info-nth-menu-item)
1137   (define-key Info-mode-map "0" 'undefined)
1138   (define-key Info-mode-map "?" 'Info-summary)
1139   (define-key Info-mode-map "]" 'Info-forward-node)
1140   (define-key Info-mode-map "[" 'Info-backward-node)
1141   (define-key Info-mode-map "<" 'Info-top-node)
1142   (define-key Info-mode-map ">" 'Info-final-node)
1143   (define-key Info-mode-map "b" 'beginning-of-buffer)
1144   (define-key Info-mode-map "d" 'Info-directory)
1145   (define-key Info-mode-map "e" 'Info-edit)
1146   (define-key Info-mode-map "f" 'Info-follow-reference)
1147   (define-key Info-mode-map "g" 'Info-goto-node)
1148   (define-key Info-mode-map "h" 'Info-help)
1149   (define-key Info-mode-map "i" 'Info-index)
1150   (define-key Info-mode-map "l" 'Info-last)
1151   (define-key Info-mode-map "m" 'Info-menu)
1152   (define-key Info-mode-map "n" 'Info-next)
1153   (define-key Info-mode-map "p" 'Info-prev)
1154   (define-key Info-mode-map "q" 'Info-exit)
1155   (define-key Info-mode-map "s" 'Info-search)
1156   (define-key Info-mode-map "t" 'Info-top-node)
1157   (define-key Info-mode-map "u" 'Info-up)
1158   (define-key Info-mode-map "," 'Info-index-next)
1159   (define-key Info-mode-map "\177" 'Info-scroll-down)
1160   (define-key Info-mode-map [mouse-2] 'Info-follow-nearest-node)
1161   )
1162 \f
1163 ;; Info mode is suitable only for specially formatted data.
1164 (put 'info-mode 'mode-class 'special)
1165
1166 (defun Info-mode ()
1167   "\\<Info-mode-map>
1168 Info mode provides commands for browsing through the Info documentation tree.
1169 Documentation in Info is divided into \"nodes\", each of which discusses
1170 one topic and contains references to other nodes which discuss related
1171 topics.  Info has commands to follow the references and show you other nodes.
1172
1173 \\[Info-help]   Invoke the Info tutorial.
1174
1175 Selecting other nodes:
1176 \\[Info-next]   Move to the \"next\" node of this node.
1177 \\[Info-prev]   Move to the \"previous\" node of this node.
1178 \\[Info-up]     Move \"up\" from this node.
1179 \\[Info-menu]   Pick menu item specified by name (or abbreviation).
1180         Picking a menu item causes another node to be selected.
1181 \\[Info-directory]      Go to the Info directory node.
1182 \\[Info-follow-reference]       Follow a cross reference.  Reads name of reference.
1183 \\[Info-last]   Move to the last node you were at.
1184 \\[Info-index]  Look up a topic in this file's Index and move to that node.
1185 \\[Info-index-next]     (comma) Move to the next match from a previous `i' command.
1186
1187 Moving within a node:
1188 \\[scroll-up]   Normally, scroll forward a full screen.  If the end of the buffer is
1189 already visible, try to go to the next menu entry, or up if there is none.
1190 \\[scroll-down]  Normally, scroll backward.  If the beginning of the buffer is
1191 already visible, try to go to the previous menu entry, or up if there is none.
1192 \\[beginning-of-buffer] Go to beginning of node.
1193
1194 Advanced commands:
1195 \\[Info-exit]   Quit Info: reselect previously selected buffer.
1196 \\[Info-edit]   Edit contents of selected node.
1197 1       Pick first item in node's menu.
1198 2, 3, 4, 5   Pick second ... fifth item in node's menu.
1199 \\[Info-goto-node]      Move to node specified by name.
1200         You may include a filename as well, as (FILENAME)NODENAME.
1201 \\[Info-search] Search through this Info file for specified regexp,
1202         and select the node in which the next occurrence is found.
1203 \\[Info-next-preorder]  Next-preorder; that is, try to go to the next menu item,
1204         and if that fails try to move up, and if that fails, tell user
1205         he/she is done reading."
1206   (kill-all-local-variables)
1207   (setq major-mode 'Info-mode)
1208   (setq mode-name "Info")
1209   (use-local-map Info-mode-map)
1210   (set-syntax-table text-mode-syntax-table)
1211   (setq local-abbrev-table text-mode-abbrev-table)
1212   (setq case-fold-search t)
1213   (setq buffer-read-only t)
1214   (make-local-variable 'Info-current-file)
1215   (make-local-variable 'Info-current-subfile)
1216   (make-local-variable 'Info-current-node)
1217   (make-local-variable 'Info-tag-table-marker)
1218   (make-local-variable 'Info-history)
1219   (make-local-variable 'Info-index-alternatives)
1220   (Info-set-mode-line)
1221   (run-hooks 'Info-mode-hook))
1222
1223 (defvar Info-edit-map nil
1224   "Local keymap used within `e' command of Info.")
1225 (if Info-edit-map
1226     nil
1227   (setq Info-edit-map (nconc (make-sparse-keymap) text-mode-map))
1228   (define-key Info-edit-map "\C-c\C-c" 'Info-cease-edit))
1229
1230 ;; Info-edit mode is suitable only for specially formatted data.
1231 (put 'info-edit-mode 'mode-class 'special)
1232
1233 (defun Info-edit-mode ()
1234   "Major mode for editing the contents of an Info node.
1235 Like text mode with the addition of `Info-cease-edit'
1236 which returns to Info mode for browsing.
1237 \\{Info-edit-map}"
1238   )
1239
1240 (defun Info-edit ()
1241   "Edit the contents of this Info node.
1242 Allowed only if variable `Info-enable-edit' is non-nil."
1243   (interactive)
1244   (or Info-enable-edit
1245       (error "Editing info nodes is not enabled"))
1246   (use-local-map Info-edit-map)
1247   (setq major-mode 'Info-edit-mode)
1248   (setq mode-name "Info Edit")
1249   (kill-local-variable 'mode-line-buffer-identification)
1250   (setq buffer-read-only nil)
1251   ;; Make mode line update.
1252   (set-buffer-modified-p (buffer-modified-p))
1253   (message (substitute-command-keys
1254              "Editing: Type \\<Info-mode-map>\\[Info-cease-edit] to return to info")))
1255
1256 (defun Info-cease-edit ()
1257   "Finish editing Info node; switch back to Info proper."
1258   (interactive)
1259   ;; Do this first, so nothing has changed if user C-g's at query.
1260   (and (buffer-modified-p)
1261        (y-or-n-p "Save the file? ")
1262        (save-buffer))
1263   (use-local-map Info-mode-map)
1264   (setq major-mode 'Info-mode)
1265   (setq mode-name "Info")
1266   (Info-set-mode-line)
1267   (setq buffer-read-only t)
1268   ;; Make mode line update.
1269   (set-buffer-modified-p (buffer-modified-p))
1270   (and (marker-position Info-tag-table-marker)
1271        (buffer-modified-p)
1272        (message "Tags may have changed.  Use Info-tagify if necessary")))
1273 \f
1274 (defun Info-find-emacs-command-nodes (command)
1275   "Return a list of locations documenting COMMAND in the Emacs Info manual.
1276 The locations are of the format used in Info-history, i.e.
1277 \(FILENAME NODENAME BUFFERPOS\)."
1278   (require 'info)
1279   (let ((where '())
1280         (cmd-desc (concat "^\\* " (regexp-quote (symbol-name command))
1281                           ":\\s *\\(.*\\)\\.$")))
1282     (save-excursion
1283       (Info-find-node "emacs" "Command Index")
1284       ;; Take the index node off the Info history.
1285       (setq Info-history (cdr Info-history))
1286       (goto-char (point-max))
1287       (while (re-search-backward cmd-desc nil t)
1288           (setq where (cons (list Info-current-file
1289                                   (buffer-substring
1290                                    (match-beginning 1)
1291                                    (match-end 1))
1292                                   0)
1293                             where)))
1294       where)))
1295
1296 ;;;###autoload
1297 (defun Info-goto-emacs-command-node (command)
1298   "Go to the Info node in the Emacs manual for command COMMAND."
1299   (interactive "CFind documentation for command: ")
1300   (or (commandp command)
1301       (signal 'wrong-type-argument (list 'commandp command)))
1302   (let ((where (Info-find-emacs-command-nodes command)))
1303     (if where
1304         (let ((num-matches (length where)))
1305           ;; Get Info running, and pop to it in another window.
1306           (save-window-excursion
1307             (info))
1308           (pop-to-buffer "*info*")
1309           (Info-find-node (car (car where))
1310                           (car (cdr (car where))))
1311           (if (> num-matches 1)
1312               (progn
1313                 ;; Info-find-node already pushed (car where) onto
1314                 ;; Info-history.  Put the other nodes that were found on
1315                 ;; the history.
1316                 (setq Info-history (nconc (cdr where) Info-history))
1317                 (message (substitute-command-keys
1318                           "Found %d other entr%.  Use \\[Info-last] to see %s."
1319                         (1- num-matches)
1320                         (if (> num-matches 2) "ies" "y")
1321                         (if (> num-matches 2) "them" "it"))))))
1322       (error "Couldn't find documentation for %s." command))))
1323
1324 ;;;###autoload
1325 (defun Info-goto-emacs-key-command-node (key)
1326   "Go to the Info node in the Emacs manual the command bound to KEY, a string.
1327 Interactively, if the binding is execute-extended-command, a command is read."
1328   (interactive "kFind documentation for key:")
1329   (let ((command (key-binding key)))
1330     (cond ((null command)
1331            (message "%s is undefined" (key-description key)))
1332           ((and (interactive-p)
1333                 (eq command 'execute-extended-command))
1334            (Info-goto-emacs-command-node
1335             (read-command "Find documentation for command: ")))
1336           (t
1337            (Info-goto-emacs-command-node command)))))
1338
1339 (provide 'info)
1340
1341 ;;; info.el ends here