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                             (".z"      . "gunzip")
  89                             (".info.Z" . "uncompress")
  90                             (".info.Y" . "unyabba")
  91                             (".info.z" . "gunzip"))
  92   "List of file name suffixes and associated decoding commands.
  93 Each entry should be (SUFFIX . STRING); the file is given to
  94 the command as standard input.  If STRING is nil, no decoding is done.")
  95
  96 (defun info-insert-file-contents (filename &optional visit)
  97   "Insert the contents of an info file in the current buffer.
  98 Do the right thing if the file has been compressed or zipped."
  99   (if (null (catch 'ok
 100               (mapcar
 101                (function
 102                 (lambda (x)
 103                   (let ((compressed (concat filename (car x))))
 104                     (if (file-exists-p compressed)
 105                         (progn
 106                           (insert-file-contents compressed visit)
 107                           (if (cdr x)
 108                               (let ((buffer-read-only nil))
 109                                 (shell-command-on-region
 110                                  (point-min) (point-max) (cdr x) t)))
 111                           (throw 'ok t))))))
 112                Info-suffix-list)
 113               nil))
 114       (error "Can't find %s or any compressed version of it!" filename)))
 115
 116 ;;;###autoload
 117 (defun info (&optional file)
 118   "Enter Info, the documentation browser.
 119 Optional argument FILE specifies the file to examine;
 120 the default is the top-level directory of Info.
 121
 122 In interactive use, a prefix argument directs this command
 123 to read a file name from the minibuffer."
 124   (interactive (if current-prefix-arg
 125                    (list (read-file-name "Info file name: " nil nil t))))
 126   (if file
 127       (Info-goto-node (concat "(" file ")"))
 128     (if (get-buffer "*info*")
 129         (switch-to-buffer "*info*")
 130       (Info-directory))))
 131
 132 ;; Go to an info node specified as separate filename and nodename.
 133 ;; no-going-back is non-nil if recovering from an error in this function;
 134 ;; it says do not attempt further (recursive) error recovery.
 135 (defun Info-find-node (filename nodename &optional no-going-back)
 136   ;; Convert filename to lower case if not found as specified.
 137   ;; Expand it.
 138   (if filename
 139       (let (temp temp-downcase found)
 140         (setq filename (substitute-in-file-name filename))
 141         (if (string= (downcase (file-name-nondirectory filename)) "dir")
 142             (setq found t)
 143           (let ((dirs (if (string-match "^\\./" filename)
 144                           ;; If specified name starts with `./'
 145                           ;; then just try current directory.
 146                           '("./")
 147                         Info-directory-list)))
 148             ;; Search the directory list for file FILENAME.
 149             (while (and dirs (not found))
 150               (setq temp (expand-file-name filename (car dirs)))
 151               (setq temp-downcase
 152                     (expand-file-name (downcase filename) (car dirs)))
 153               ;; Try several variants of specified name.
 154               (catch 'foundit
 155                 (mapcar
 156                  (function
 157                   (lambda (x)
 158                     (if (file-exists-p (concat temp (car x)))
 159                         (progn
 160                           (setq found temp)
 161                           (throw 'foundit nil)))
 162                     (if (file-exists-p (concat temp-downcase (car x)))
 163                         (progn
 164                           (setq found temp-downcase)
 165                           (throw 'foundit nil)))))
 166                  Info-suffix-list))
 167               (setq dirs (cdr dirs)))))
 168         (if found
 169             (setq filename found)
 170           (error "Info file %s does not exist" filename))))
 171   ;; Record the node we are leaving.
 172   (if (and Info-current-file (not no-going-back))
 173       (setq Info-history
 174             (cons (list Info-current-file Info-current-node (point))
 175                   Info-history)))
 176   ;; Go into info buffer.
 177   (switch-to-buffer "*info*")
 178   (buffer-disable-undo (current-buffer))
 179   (or (eq major-mode 'Info-mode)
 180       (Info-mode))
 181   (widen)
 182   (setq Info-current-node nil)
 183   (unwind-protect
 184       (progn
 185         ;; Switch files if necessary
 186         (or (null filename)
 187             (equal Info-current-file filename)
 188             (let ((buffer-read-only nil))
 189               (setq Info-current-file nil
 190                     Info-current-subfile nil
 191                     Info-index-alternatives nil
 192                     buffer-file-name nil)
 193               (erase-buffer)
 194               (if (eq filename t)
 195                   (Info-insert-dir)
 196                 (info-insert-file-contents filename t)
 197                 (setq default-directory (file-name-directory filename)))
 198               (set-buffer-modified-p nil)
 199               ;; See whether file has a tag table.  Record the location if yes.
 200               (set-marker Info-tag-table-marker nil)
 201               (goto-char (point-max))
 202               (forward-line -8)
 203               (or (equal nodename "*")
 204                   (not (search-forward "\^_\nEnd tag table\n" nil t))
 205                   (let (pos)
 206                     ;; We have a tag table.  Find its beginning.
 207                     ;; Is this an indirect file?
 208                     (search-backward "\nTag table:\n")
 209                     (setq pos (point))
 210                     (if (save-excursion
 211                           (forward-line 2)
 212                           (looking-at "(Indirect)\n"))
 213                         ;; It is indirect.  Copy it to another buffer
 214                         ;; and record that the tag table is in that buffer.
 215                         (save-excursion
 216                           (let ((buf (current-buffer)))
 217                             (set-buffer (get-buffer-create " *info tag table*"))
 218                             (buffer-disable-undo (current-buffer))
 219                             (setq case-fold-search t)
 220                             (erase-buffer)
 221                             (insert-buffer-substring buf)
 222                             (set-marker Info-tag-table-marker
 223                                         (match-end 0))))
 224                       (set-marker Info-tag-table-marker pos))))
 225               (setq Info-current-file
 226                     (if (eq filename t) "dir"
 227                       (file-name-sans-versions buffer-file-name)))))
 228         (if (equal nodename "*")
 229             (progn (setq Info-current-node nodename)
 230                    (Info-set-mode-line))
 231           ;; Search file for a suitable node.
 232           (let ((guesspos (point-min))
 233                 (regexp (concat "Node: *" (regexp-quote nodename) " *[,\t\n\177]")))
 234             ;; First get advice from tag table if file has one.
 235             ;; Also, if this is an indirect info file,
 236             ;; read the proper subfile into this buffer.
 237             (if (marker-position Info-tag-table-marker)
 238                 (save-excursion
 239                   (set-buffer (marker-buffer Info-tag-table-marker))
 240                   (goto-char Info-tag-table-marker)
 241                   (if (re-search-forward regexp nil t)
 242                       (progn
 243                         (setq guesspos (read (current-buffer)))
 244                         ;; If this is an indirect file,
 245                         ;; determine which file really holds this node
 246                         ;; and read it in.
 247                         (if (not (eq (current-buffer) (get-buffer "*info*")))
 248                             (setq guesspos
 249                                   (Info-read-subfile guesspos))))
 250                     (error "No such node: \"%s\"" nodename))))
 251             (goto-char (max (point-min) (- guesspos 1000)))
 252             ;; Now search from our advised position (or from beg of buffer)
 253             ;; to find the actual node.
 254             (catch 'foo
 255               (while (search-forward "\n\^_" nil t)
 256                 (forward-line 1)
 257                 (let ((beg (point)))
 258                   (forward-line 1)
 259                   (if (re-search-backward regexp beg t)
 260                       (throw 'foo t))))
 261               (error "No such node: %s" nodename)))
 262           (Info-select-node)))
 263     ;; If we did not finish finding the specified node,
 264     ;; go back to the previous one.
 265     (or Info-current-node no-going-back
 266         (let ((hist (car Info-history)))
 267           (setq Info-history (cdr Info-history))
 268           (Info-find-node (nth 0 hist) (nth 1 hist) t)
 269           (goto-char (nth 2 hist)))))
 270   (goto-char (point-min)))
 271
 272 ;; Cache the contents of the (virtual) dir file, once we have merged
 273 ;; it for the first time, so we can save time subsequently.
 274 (defvar Info-dir-contents nil)
 275
 276 ;; Cache for the directory we decided to use for the default-directory
 277 ;; of the merged dir text.
 278 (defvar Info-dir-contents-directory nil)
 279
 280 ;; Construct the Info directory node by merging the files named `dir'
 281 ;; from various directories.  Set the *info* buffer's
 282 ;; default-directory to the first directory we actually get any text
 283 ;; from.
 284 (defun Info-insert-dir ()
 285   (if Info-dir-contents
 286       (insert Info-dir-contents)
 287     (let ((dirs Info-directory-list)
 288           buffers buffer others nodes dirs-done)
 289
 290       ;; Search the directory list for the directory file.
 291       (while dirs
 292         (or (member (file-truename (expand-file-name (car dirs))) dirs-done)
 293             (member (directory-file-name (file-truename (expand-file-name (car dirs))))
 294                     dirs-done)
 295             ;; Try several variants of specified name.
 296             ;; Try upcasing, appending `.info', or both.
 297             (let* (temp
 298                    (buffer
 299                     (cond
 300                      ((progn (setq temp (expand-file-name "DIR" (car dirs)))
 301                              (file-exists-p temp))
 302                       (find-file-noselect temp))
 303                      ((progn (setq temp (expand-file-name "dir" (car dirs)))
 304                              (file-exists-p temp))
 305                       (find-file-noselect temp))
 306                      ((progn (setq temp (expand-file-name "DIR.INFO" (car dirs)))
 307                              (file-exists-p temp))
 308                       (find-file-noselect temp))
 309                      ((progn (setq temp (expand-file-name "dir.info" (car dirs)))
 310                              (file-exists-p temp))
 311                       (find-file-noselect temp)))))
 312               (setq dirs-done
 313                     (cons (file-truename (expand-file-name (car dirs)))
 314                           (cons (directory-file-name
 315                                  (file-truename (expand-file-name (car dirs))))
 316                                 dirs-done)))
 317               (if buffer (setq buffers (cons buffer buffers)))))
 318         (setq dirs (cdr dirs)))
 319
 320       ;; Distinguish the dir file that comes with Emacs from all the
 321       ;; others.  Yes, that is really what this is supposed to do.
 322       ;; If it doesn't work, fix it.
 323       (setq buffer (car buffers)
 324             others (cdr buffers))
 325
 326       ;; Insert the entire original dir file as a start; use its
 327       ;; default directory as the default directory for the whole
 328       ;; concatenation.
 329       (insert-buffer buffer)
 330       (setq Info-dir-contents-directory (save-excursion
 331                                           (set-buffer buffer)
 332                                           default-directory))
 333
 334       ;; Look at each of the other buffers one by one.
 335       (while others
 336         (let ((other (car others)))
 337           ;; In each, find all the menus.
 338           (save-excursion
 339             (set-buffer other)
 340             (goto-char (point-min))
 341             ;; Find each menu, and add an elt to NODES for it.
 342             (while (re-search-forward "^\\* Menu:" nil t)
 343               (let (beg nodename end)
 344                 (forward-line 1)
 345                 (setq beg (point))
 346                 (search-backward "\n\x1f")
 347                 (search-forward "Node: ")
 348                 (setq nodename (Info-following-node-name))
 349                 (search-forward "\n\x1f" nil 'move)
 350                 (beginning-of-line)
 351                 (setq end (point))
 352                 (setq nodes (cons (list nodename other beg end) nodes))))))
 353         (setq others (cdr others)))
 354       ;; Add to the main menu a menu item for each other node.
 355       (re-search-forward "^\\* Menu:")
 356       (forward-line 1)
 357       (let ((menu-items '("top"))
 358             (nodes nodes)
 359             (case-fold-search t)
 360             (end (save-excursion (search-forward "\x1f" nil t) (point))))
 361         (while nodes
 362           (let ((nodename (car (car nodes))))
 363             (or (member (downcase nodename) menu-items)
 364                 (re-search-forward (concat "^\\* " (regexp-quote nodename) ":")
 365                                    end t)
 366                 (progn
 367                   (insert "* " nodename "\n")
 368                   (setq menu-items (cons nodename menu-items)))))
 369           (setq nodes (cdr nodes))))
 370       ;; Now take each node of each of the other buffers
 371       ;; and merge it into the main buffer.
 372       (while nodes
 373         (let ((nodename (car (car nodes))))
 374           (goto-char (point-min))
 375           ;; Find the like-named node in the main buffer.
 376           (if (re-search-forward (concat "\n\x1f.*\n.*Node: "
 377                                          (regexp-quote nodename)
 378                                          "[,\n\t]")
 379                                  nil t)
 380               (progn
 381                 (search-forward "\n\x1f" nil 'move)
 382                 (beginning-of-line))
 383             ;; If none exists, add one.
 384             (goto-char (point-max))
 385             (insert "\x1f\nFile: dir\tnode: " nodename "\n\n* Menu:\n\n"))
 386           ;; Merge the text from the other buffer's menu
 387           ;; into the menu in the like-named node in the main buffer.
 388           (apply 'insert-buffer-substring (cdr (car nodes)))
 389           (insert "\n"))
 390         (setq nodes (cdr nodes)))
 391       ;; Kill all the buffers we just made.
 392       (while buffers
 393         (kill-buffer (car buffers))
 394         (setq buffers (cdr buffers))))
 395     (setq Info-dir-contents (buffer-string)))
 396   (setq default-directory Info-dir-contents-directory))
 397
 398 (defun Info-read-subfile (nodepos)
 399   (set-buffer (marker-buffer Info-tag-table-marker))
 400   (goto-char (point-min))
 401   (search-forward "\n\^_")
 402   (let (lastfilepos
 403         lastfilename)
 404     (forward-line 2)
 405     (catch 'foo
 406       (while (not (looking-at "\^_"))
 407         (if (not (eolp))
 408             (let ((beg (point))
 409                   thisfilepos thisfilename)
 410               (search-forward ": ")
 411               (setq thisfilename  (buffer-substring beg (- (point) 2)))
 412               (setq thisfilepos (read (current-buffer)))
 413               ;; read in version 19 stops at the end of number.
 414               ;; Advance to the next line.
 415               (forward-line 1)
 416               (if (> thisfilepos nodepos)
 417                   (throw 'foo t))
 418               (setq lastfilename thisfilename)
 419               (setq lastfilepos thisfilepos))
 420           (forward-line 1))))
 421     (set-buffer (get-buffer "*info*"))
 422     (or (equal Info-current-subfile lastfilename)
 423         (let ((buffer-read-only nil))
 424           (setq buffer-file-name nil)
 425           (widen)
 426           (erase-buffer)
 427           (info-insert-file-contents lastfilename)
 428           (set-buffer-modified-p nil)
 429           (setq Info-current-subfile lastfilename)))
 430     (goto-char (point-min))
 431     (search-forward "\n\^_")
 432     (+ (- nodepos lastfilepos) (point))))
 433
 434 ;; Select the info node that point is in.
 435 (defun Info-select-node ()
 436   (save-excursion
 437    ;; Find beginning of node.
 438    (search-backward "\n\^_")
 439    (forward-line 2)
 440    ;; Get nodename spelled as it is in the node.
 441    (re-search-forward "Node:[ \t]*")
 442    (setq Info-current-node
 443          (buffer-substring (point)
 444                            (progn
 445                             (skip-chars-forward "^,\t\n")
 446                             (point))))
 447    (Info-set-mode-line)
 448    ;; Find the end of it, and narrow.
 449    (beginning-of-line)
 450    (let (active-expression)
 451      (narrow-to-region (point)
 452                        (if (re-search-forward "\n[\^_\f]" nil t)
 453                            (prog1
 454                             (1- (point))
 455                             (if (looking-at "[\n\^_\f]*execute: ")
 456                                 (progn
 457                                   (goto-char (match-end 0))
 458                                   (setq active-expression
 459                                         (read (current-buffer))))))
 460                          (point-max)))
 461      (if Info-enable-active-nodes (eval active-expression)))))
 462
 463 (defun Info-set-mode-line ()
 464   (setq mode-line-buffer-identification
 465         (concat
 466          "Info:  ("
 467          (if Info-current-file
 468              (file-name-nondirectory Info-current-file)
 469            "")
 470          ")"
 471          (or Info-current-node ""))))
 472 \f
 473 ;; Go to an info node specified with a filename-and-nodename string
 474 ;; of the sort that is found in pointers in nodes.
 475
 476 (defun Info-goto-node (nodename)
 477   "Go to info node named NAME.  Give just NODENAME or (FILENAME)NODENAME."
 478   (interactive "sGoto node: ")
 479   (let (filename)
 480     (string-match "\\s *\\((\\s *\\([^\t)]*\\)\\s *)\\s *\\|\\)\\(.*\\)"
 481                   nodename)
 482     (setq filename (if (= (match-beginning 1) (match-end 1))
 483                        ""
 484                      (substring nodename (match-beginning 2) (match-end 2)))
 485           nodename (substring nodename (match-beginning 3) (match-end 3)))
 486     (let ((trim (string-match "\\s *\\'" filename)))
 487       (if trim (setq filename (substring filename 0 trim))))
 488     (let ((trim (string-match "\\s *\\'" nodename)))
 489       (if trim (setq nodename (substring nodename 0 trim))))
 490     (Info-find-node (if (equal filename "") nil filename)
 491                     (if (equal nodename "") "Top" nodename))))
 492 \f
 493 (defun Info-restore-point (hl)
 494   "If this node has been visited, restore the point value when we left."
 495   (if hl
 496       (if (and (equal (nth 0 (car hl)) Info-current-file)
 497                (equal (nth 1 (car hl)) Info-current-node))
 498           (goto-char (nth 2 (car hl)))
 499         (Info-restore-point (cdr hl)))))
 500 \f
 501 (defvar Info-last-search nil
 502   "Default regexp for \\<Info-mode-map>\\[Info-search] command to search for.")
 503
 504 (defun Info-search (regexp)
 505   "Search for REGEXP, starting from point, and select node it's found in."
 506   (interactive "sSearch (regexp): ")
 507   (if (equal regexp "")
 508       (setq regexp Info-last-search)
 509     (setq Info-last-search regexp))
 510   (let ((found ()) current
 511         (onode Info-current-node)
 512         (ofile Info-current-file)
 513         (opoint (point))
 514         (osubfile Info-current-subfile))
 515     (save-excursion
 516       (save-restriction
 517         (widen)
 518         (if (null Info-current-subfile)
 519             (progn (re-search-forward regexp) (setq found (point)))
 520           (condition-case err
 521               (progn (re-search-forward regexp) (setq found (point)))
 522             (search-failed nil)))))
 523     (if (not found) ;can only happen in subfile case -- else would have erred
 524         (unwind-protect
 525             (let ((list ()))
 526               (set-buffer (marker-buffer Info-tag-table-marker))
 527               (goto-char (point-min))
 528               (search-forward "\n\^_\nIndirect:")
 529               (save-restriction
 530                 (narrow-to-region (point)
 531                                   (progn (search-forward "\n\^_")
 532                                          (1- (point))))
 533                 (goto-char (point-min))
 534                 (search-forward (concat "\n" osubfile ": "))
 535                 (beginning-of-line)
 536                 (while (not (eobp))
 537                   (re-search-forward "\\(^.*\\): [0-9]+$")
 538                   (goto-char (+ (match-end 1) 2))
 539                   (setq list (cons (cons (read (current-buffer))
 540                                          (buffer-substring (match-beginning 1)
 541                                                            (match-end 1)))
 542                                    list))
 543                   (goto-char (1+ (match-end 0))))
 544                 (setq list (nreverse list)
 545                       current (car (car list))
 546                       list (cdr list)))
 547               (while list
 548                 (message "Searching subfile %s..." (cdr (car list)))
 549                 (Info-read-subfile (car (car list)))
 550                 (setq list (cdr list))
 551                 (goto-char (point-min))
 552                 (if (re-search-forward regexp nil t)
 553                     (setq found (point) list ())))
 554               (if found
 555                   (message "")
 556                 (signal 'search-failed (list regexp))))
 557           (if (not found)
 558               (progn (Info-read-subfile opoint)
 559                      (goto-char opoint)
 560                      (Info-select-node)))))
 561     (widen)
 562     (goto-char found)
 563     (Info-select-node)
 564     (or (and (equal onode Info-current-node)
 565              (equal ofile Info-current-file))
 566         (setq Info-history (cons (list ofile onode opoint)
 567                                  Info-history)))))
 568 \f
 569 ;; Extract the value of the node-pointer named NAME.
 570 ;; If there is none, use ERRORNAME in the error message;
 571 ;; if ERRORNAME is nil, just return nil.
 572 (defun Info-extract-pointer (name &optional errorname)
 573   (save-excursion
 574    (goto-char (point-min))
 575    (forward-line 1)
 576    (if (re-search-backward (concat name ":") nil t)
 577        (progn
 578          (goto-char (match-end 0))
 579          (Info-following-node-name))
 580      (if (eq errorname t)
 581          nil
 582        (error (concat "Node has no " (capitalize (or errorname name))))))))
 583
 584 ;; Return the node name in the buffer following point.
 585 ;; ALLOWEDCHARS, if non-nil, goes within [...] to make a regexp
 586 ;; saying which chas may appear in the node name.
 587 (defun Info-following-node-name (&optional allowedchars)
 588   (skip-chars-forward " \t")
 589   (buffer-substring
 590    (point)
 591    (progn
 592      (while (looking-at (concat "[" (or allowedchars "^,\t\n") "]"))
 593        (skip-chars-forward (concat (or allowedchars "^,\t\n") "("))
 594        (if (looking-at "(")
 595            (skip-chars-forward "^)")))
 596      (skip-chars-backward " ")
 597      (point))))
 598
 599 (defun Info-next ()
 600   "Go to the next node of this node."
 601   (interactive)
 602   (Info-goto-node (Info-extract-pointer "next")))
 603
 604 (defun Info-prev ()
 605   "Go to the previous node of this node."
 606   (interactive)
 607   (Info-goto-node (Info-extract-pointer "prev[ious]*" "previous")))
 608
 609 (defun Info-up ()
 610   "Go to the superior node of this node."
 611   (interactive)
 612   (Info-goto-node (Info-extract-pointer "up"))
 613   (Info-restore-point Info-history))
 614
 615 (defun Info-last ()
 616   "Go back to the last node visited."
 617   (interactive)
 618   (or Info-history
 619       (error "This is the first Info node you looked at"))
 620   (let (filename nodename opoint)
 621     (setq filename (car (car Info-history)))
 622     (setq nodename (car (cdr (car Info-history))))
 623     (setq opoint (car (cdr (cdr (car Info-history)))))
 624     (setq Info-history (cdr Info-history))
 625     (Info-find-node filename nodename)
 626     (setq Info-history (cdr Info-history))
 627     (goto-char opoint)))
 628
 629 (defun Info-directory ()
 630   "Go to the Info directory node."
 631   (interactive)
 632   (Info-find-node "dir" "top"))
 633 \f
 634 (defun Info-follow-reference (footnotename)
 635   "Follow cross reference named NAME to the node it refers to.
 636 NAME may be an abbreviation of the reference name."
 637   (interactive
 638    (let ((completion-ignore-case t)
 639          completions default (start-point (point)) str i)
 640      (save-excursion
 641        (goto-char (point-min))
 642        (while (re-search-forward "\\*note[ \n\t]*\\([^:]*\\):" nil t)
 643          (setq str (buffer-substring
 644                     (match-beginning 1)
 645                     (1- (point))))
 646          ;; See if this one should be the default.
 647          (and (null default)
 648               (< (match-beginning 0) start-point)
 649               (<= start-point (point))
 650               (setq default t))
 651          (setq i 0)
 652          (while (setq i (string-match "[ \n\t]+" str i))
 653            (setq str (concat (substring str 0 i) " "
 654                              (substring str (match-end 0))))
 655            (setq i (1+ i)))
 656          ;; Record as a completion and perhaps as default.
 657          (if (eq default t) (setq default str))
 658          (setq completions
 659                (cons (cons str nil)
 660                      completions))))
 661      (if completions
 662          (list (completing-read (if default
 663                                     (concat "Follow reference named: ("
 664                                             default ") ")
 665                                   "Follow reference named: ")
 666                                 completions default t))
 667        (error "No cross-references in this node"))))
 668   (let (target beg i (str (concat "\\*note " footnotename)))
 669     (while (setq i (string-match " " str i))
 670       (setq str (concat (substring str 0 i) "[ \t\n]+" (substring str (1+ i))))
 671       (setq i (+ i 6)))
 672     (save-excursion
 673       (goto-char (point-min))
 674       (or (re-search-forward str nil t)
 675           (error "No cross-reference named %s" footnotename))
 676       (goto-char (+ (match-beginning 0) 5))
 677       (setq target
 678             (Info-extract-menu-node-name "Bad format cross reference" t)))
 679     (while (setq i (string-match "[ \t\n]+" target i))
 680       (setq target (concat (substring target 0 i) " "
 681                            (substring target (match-end 0))))
 682       (setq i (+ i 1)))
 683     (Info-goto-node target)))
 684
 685 (defun Info-extract-menu-node-name (&optional errmessage multi-line)
 686   (skip-chars-forward " \t\n")
 687   (let ((beg (point))
 688         str i)
 689     (skip-chars-forward "^:")
 690     (forward-char 1)
 691     (setq str
 692           (if (looking-at ":")
 693               (buffer-substring beg (1- (point)))
 694             (skip-chars-forward " \t\n")
 695             (Info-following-node-name (if multi-line "^.,\t" "^.,\t\n"))))
 696     (while (setq i (string-match "\n" str i))
 697       (aset str i ?\ ))
 698     str))
 699
 700 ;; No one calls this and Info-menu-item doesn't exist.
 701 ;;(defun Info-menu-item-sequence (list)
 702 ;;  (while list
 703 ;;    (Info-menu-item (car list))
 704 ;;    (setq list (cdr list))))
 705
 706 (defun Info-menu (menu-item)
 707   "Go to node for menu item named (or abbreviated) NAME.
 708 Completion is allowed, and the menu item point is on is the default."
 709   (interactive
 710    (let ((completions '())
 711          ;; If point is within a menu item, use that item as the default
 712          (default nil)
 713          (p (point))
 714          (last nil))
 715      (save-excursion
 716        (goto-char (point-min))
 717        (if (not (search-forward "\n* menu:" nil t))
 718            (error "No menu in this node"))
 719        (while (re-search-forward
 720                 "\n\\* \\([^:\t\n]*\\):" nil t)
 721          (if (and (null default)
 722                   (prog1 (if last (< last p) nil)
 723                     (setq last (match-beginning 0)))
 724                   (<= p last))
 725              (setq default (car (car completions))))
 726          (setq completions (cons (cons (buffer-substring
 727                                          (match-beginning 1)
 728                                          (match-end 1))
 729                                        (match-beginning 1))
 730                                  completions)))
 731        (if (and (null default) last
 732                 (< last p)
 733                 (<= p (progn (end-of-line) (point))))
 734            (setq default (car (car completions)))))
 735      (let ((item nil))
 736        (while (null item)
 737          (setq item (let ((completion-ignore-case t))
 738                       (completing-read (if default
 739                                            (format "Menu item (default %s): "
 740                                                    default)
 741                                            "Menu item: ")
 742                                        completions nil t)))
 743          ;; we rely on the fact that completing-read accepts an input
 744          ;; of "" even when the require-match argument is true and ""
 745          ;; is not a valid possibility
 746          (if (string= item "")
 747              (if default
 748                  (setq item default)
 749                  ;; ask again
 750                  (setq item nil))))
 751        (list item))))
 752   ;; there is a problem here in that if several menu items have the same
 753   ;; name you can only go to the node of the first with this command.
 754   (Info-goto-node (Info-extract-menu-item menu-item)))
 755
 756 (defun Info-extract-menu-item (menu-item)
 757   (setq menu-item (regexp-quote menu-item))
 758   (save-excursion
 759     (goto-char (point-min))
 760     (or (search-forward "\n* menu:" nil t)
 761         (error "No menu in this node"))
 762     (or (re-search-forward (concat "\n* " menu-item ":") nil t)
 763         (re-search-forward (concat "\n* " menu-item) nil t)
 764         (error "No such item in menu"))
 765     (beginning-of-line)
 766     (forward-char 2)
 767     (Info-extract-menu-node-name)))
 768
 769 ;; If COUNT is nil, use the last item in the menu.
 770 (defun Info-extract-menu-counting (count)
 771   (save-excursion
 772     (goto-char (point-min))
 773     (or (search-forward "\n* menu:" nil t)
 774         (error "No menu in this node"))
 775     (if count
 776         (or (search-forward "\n* " nil t count)
 777             (error "Too few items in menu"))
 778       (while (search-forward "\n* " nil t)
 779         nil))
 780     (Info-extract-menu-node-name)))
 781
 782 (defun Info-nth-menu-item ()
 783   "Go to the node of the Nth menu item.
 784 N is the digit argument used to invoke this command."
 785   (interactive)
 786   (Info-goto-node
 787    (Info-extract-menu-counting
 788     (- (aref (this-command-keys) (1- (length (this-command-keys)))) ?0))))
 789
 790 (defun Info-top-node ()
 791   "Go to the Top node of this file."
 792   (interactive)
 793   (Info-goto-node "Top"))
 794
 795 (defun Info-final-node ()
 796   "Go to the final node in this file."
 797   (interactive)
 798   (Info-goto-node "Top")
 799   (let (Info-history)
 800     ;; Go to the last node in the menu of Top.
 801     (Info-goto-node (Info-extract-menu-counting nil))
 802     ;; If the last node in the menu is not last in pointer structure,
 803     ;; move forward until we can't go any farther.
 804     (while (Info-forward-node t t) nil)
 805     ;; Then keep moving down to last subnode, unless we reach an index.
 806     (while (and (not (string-match "\\<index\\>" Info-current-node))
 807                 (save-excursion (search-forward "\n* Menu:" nil t)))
 808       (Info-goto-node (Info-extract-menu-counting nil)))))
 809
 810 (defun Info-forward-node (&optional not-down no-error)
 811   "Go forward one node, considering all nodes as forming one sequence."
 812   (interactive)
 813   (goto-char (point-min))
 814   (forward-line 1)
 815   ;; three possibilities, in order of priority:
 816   ;;     1. next node is in a menu in this node (but not in an index)
 817   ;;     2. next node is next at same level
 818   ;;     3. next node is up and next
 819   (cond ((and (not not-down)
 820               (save-excursion (search-forward "\n* menu:" nil t))
 821               (not (string-match "\\<index\\>" Info-current-node)))
 822          (Info-goto-node (Info-extract-menu-counting 1))
 823          t)
 824         ((save-excursion (search-backward "next:" nil t))
 825          (Info-next)
 826          t)
 827         ((and (save-excursion (search-backward "up:" nil t))
 828               (not (equal (downcase (Info-extract-pointer "up")) "top")))
 829          (let ((old-node Info-current-node))
 830            (Info-up)
 831            (let (Info-history success)
 832              (unwind-protect
 833                  (setq success (Info-forward-node t no-error))
 834                (or success (Info-goto-node old-node))))))
 835         (no-error nil)
 836         (t (error "No pointer forward from this node"))))
 837
 838 (defun Info-backward-node ()
 839   "Go backward one node, considering all nodes as forming one sequence."
 840   (interactive)
 841   (let ((prevnode (Info-extract-pointer "prev[ious]*" t))
 842         (upnode (Info-extract-pointer "up" t)))
 843     (cond ((and upnode (string-match "(" upnode))
 844            (error "First node in file"))
 845           ((and upnode (or (null prevnode)
 846                            (equal (downcase prevnode) (downcase upnode))))
 847            (Info-up))
 848           (prevnode
 849            ;; If we move back at the same level,
 850            ;; go down to find the last subnode*.
 851            (Info-prev)
 852            (let (Info-history)
 853              (while (and (not (string-match "\\<index\\>" Info-current-node))
 854                          (save-excursion (search-forward "\n* Menu:" nil t)))
 855                (Info-goto-node (Info-extract-menu-counting nil)))))
 856           (t
 857            (error "No pointer backward from this node")))))
 858
 859 (defun Info-exit ()
 860   "Exit Info by selecting some other buffer."
 861   (interactive)
 862   (switch-to-buffer (prog1 (other-buffer (current-buffer))
 863                            (bury-buffer (current-buffer)))))
 864
 865 (defun Info-next-menu-item ()
 866   (interactive)
 867   (save-excursion
 868     (forward-line -1)
 869     (search-forward "\n* menu:" nil t)
 870     (or (search-forward "\n* " nil t)
 871         (error "No more items in menu"))
 872     (Info-goto-node (Info-extract-menu-node-name))))
 873
 874 (defun Info-last-menu-item ()
 875   (interactive)
 876   (save-excursion
 877     (forward-line 1)
 878     (search-backward "\n* menu:" nil t)
 879     (or (search-backward "\n* " nil t)
 880         (error "No previous items in menu"))
 881     (Info-goto-node (Info-extract-menu-node-name))))
 882
 883 (defmacro no-error (&rest body)
 884   (list 'condition-case nil (cons 'progn (append body '(t))) '(error nil)))
 885
 886 (defun Info-next-preorder ()
 887   "Go to the next node, popping up a level if there is none."
 888   (interactive)
 889   (cond ((no-error (Info-next-menu-item))       )
 890         ((no-error (Info-up))                   (forward-line 1))
 891         (t                                      (error "No more nodes"))))
 892
 893 (defun Info-last-preorder ()
 894   "Go to the last node, popping up a level if there is none."
 895   (interactive)
 896   (cond ((no-error (Info-last-menu-item))       )
 897         ((no-error (Info-up))                   (forward-line -1))
 898         (t                                      (error "No previous nodes"))))
 899
 900 (defun Info-scroll-up ()
 901   "Read the next screen.  If end of buffer is visible, go to next entry."
 902   (interactive)
 903   (if (pos-visible-in-window-p (point-max))
 904       (Info-next-preorder)
 905       (scroll-up))
 906   )
 907
 908 (defun Info-scroll-down ()
 909   "Read the previous screen.  If start of buffer is visible, go to last entry."
 910   (interactive)
 911   (if (pos-visible-in-window-p (point-min))
 912       (Info-last-preorder)
 913       (scroll-down))
 914   )
 915
 916 (defun Info-index (topic)
 917   "Look up a string in the index for this file.
 918 The index is defined as the first node in the top-level menu whose
 919 name contains the word \"Index\", plus any immediately following
 920 nodes whose names also contain the word \"Index\".
 921 If there are no exact matches to the specified topic, this chooses
 922 the first match which is a case-insensitive substring of a topic.
 923 Use the `,' command to see the other matches.
 924 Give a blank topic name to go to the Index node itself."
 925   (interactive "sIndex topic: ")
 926   (let ((orignode Info-current-node)
 927         (rnode nil)
 928         (pattern (format "\n\\* \\([^\n:]*%s[^\n:]*\\):[ \t]*\\([^.\n]*\\)\\.[ t]*\\([0-9]*\\)"
 929                          (regexp-quote topic)))
 930         node)
 931     (Info-goto-node "Top")
 932     (or (search-forward "\n* menu:" nil t)
 933         (error "No index"))
 934     (or (re-search-forward "\n\\* \\(.*\\<Index\\>\\)" nil t)
 935         (error "No index"))
 936     (goto-char (match-beginning 1))
 937     (let ((Info-keeping-history nil))
 938       (Info-goto-node (Info-extract-menu-node-name)))
 939     (or (equal topic "")
 940         (let ((matches nil)
 941               (exact nil)
 942               (Info-keeping-history nil)
 943               found)
 944           (while
 945               (progn
 946                 (goto-char (point-min))
 947                 (while (re-search-forward pattern nil t)
 948                   (setq matches
 949                         (cons (list (buffer-substring (match-beginning 1)
 950                                                       (match-end 1))
 951                                     (buffer-substring (match-beginning 2)
 952                                                       (match-end 2))
 953                                     Info-current-node
 954                                     (string-to-int (concat "0"
 955                                                            (buffer-substring
 956                                                             (match-beginning 3)
 957                                                             (match-end 3)))))
 958                               matches)))
 959                 (and (setq node (Info-extract-pointer "next" t))
 960                      (string-match "\\<Index\\>" node)))
 961             (Info-goto-node node))
 962           (or matches
 963               (progn
 964                 (Info-last)
 965                 (error "No \"%s\" in index" topic)))
 966           ;; Here it is a feature that assoc is case-sensitive.
 967           (while (setq found (assoc topic matches))
 968             (setq exact (cons found exact)
 969                   matches (delq found matches)))
 970           (setq Info-index-alternatives (nconc exact (nreverse matches)))
 971           (Info-index-next 0)))))
 972
 973 (defun Info-index-next (num)
 974   "Go to the next matching index item from the last `i' command."
 975   (interactive "p")
 976   (or Info-index-alternatives
 977       (error "No previous `i' command in this file"))
 978   (while (< num 0)
 979     (setq num (+ num (length Info-index-alternatives))))
 980   (while (> num 0)
 981     (setq Info-index-alternatives
 982           (nconc (cdr Info-index-alternatives)
 983                  (list (car Info-index-alternatives)))
 984           num (1- num)))
 985   (Info-goto-node (nth 1 (car Info-index-alternatives)))
 986   (if (> (nth 3 (car Info-index-alternatives)) 0)
 987       (forward-line (nth 3 (car Info-index-alternatives)))
 988     (forward-line 3)  ; don't search in headers
 989     (let ((name (car (car Info-index-alternatives))))
 990       (if (or (re-search-forward (format
 991                                   "\\(Function\\|Command\\): %s\\( \\|$\\)"
 992                                   (regexp-quote name)) nil t)
 993               (search-forward (format "`%s'" name) nil t)
 994               (and (string-match "\\`.*\\( (.*)\\)\\'" name)
 995                    (search-forward
 996                     (format "`%s'" (substring name 0 (match-beginning 1)))
 997                     nil t))
 998               (search-forward name nil t))
 999           (beginning-of-line)
1000         (goto-char (point-min)))))
1001   (message "Found \"%s\" in %s.  %s"
1002            (car (car Info-index-alternatives))
1003            (nth 2 (car Info-index-alternatives))
1004            (if (cdr Info-index-alternatives)
1005                "(Press `,' for more)"
1006              "(Only match)")))
1007
1008 (defun Info-undefined ()
1009   "Make command be undefined in Info."
1010   (interactive)
1011   (ding))
1012
1013 (defun Info-help ()
1014   "Enter the Info tutorial."
1015   (interactive)
1016   (delete-other-windows)
1017   (Info-find-node "info"
1018                   (if (< (window-height) 23)
1019                       "Help-Small-Screen"
1020                     "Help")))
1021
1022 (defun Info-summary ()
1023   "Display a brief summary of all Info commands."
1024   (interactive)
1025   (save-window-excursion
1026     (switch-to-buffer "*Help*")
1027     (erase-buffer)
1028     (insert (documentation 'Info-mode))
1029     (goto-char (point-min))
1030     (let (ch flag)
1031       (while (progn (setq flag (not (pos-visible-in-window-p (point-max))))
1032                     (message (if flag "Type Space to see more"
1033                                "Type Space to return to Info"))
1034                     (if (not (eq ?\  (setq ch (read-event))))
1035                         (progn (setq unread-command-events (list ch)) nil)
1036                       flag))
1037         (scroll-up)))))
1038 \f
1039 (defun Info-get-token (pos start all &optional errorstring)
1040   "Return the token around POS,
1041 POS must be somewhere inside the token
1042 START is a regular expression which will match the
1043     beginning of the tokens delimited string
1044 ALL is a regular expression with a single
1045     parenthized subpattern which is the token to be
1046     returned. E.g. '{\(.*\)}' would return any string
1047     enclosed in braces around POS.
1048 SIG optional fourth argument, controls action on no match
1049     nil: return nil
1050     t: beep
1051     a string: signal an error, using that string."
1052   (save-excursion
1053     (goto-char pos)
1054     (re-search-backward start (max (point-min) (- pos 200)) 'yes)
1055     (let (found)
1056       (while (and (re-search-forward all (min (point-max) (+ pos 200)) 'yes)
1057                   (not (setq found (and (<= (match-beginning 0) pos)
1058                                         (> (match-end 0) pos))))))
1059       (if (and found (<= (match-beginning 0) pos)
1060                (> (match-end 0) pos))
1061           (buffer-substring (match-beginning 1) (match-end 1))
1062         (cond ((null errorstring)
1063                nil)
1064               ((eq errorstring t)
1065                (beep)
1066                nil)
1067               (t
1068                (error "No %s around position %d" errorstring pos)))))))
1069
1070 (defun Info-follow-nearest-node (click)
1071   "\\<Info-mode-map>Follow a node reference near point.
1072 Like \\[Info-menu], \\[Info-follow-reference], \\[Info-next], \\[Info-prev] or \\[Info-up] command, depending on where you click.
1073 At end of the node's text, moves to the next node."
1074   (interactive "e")
1075   (let* ((start (event-start click))
1076          (window (car start))
1077          (pos (car (cdr start))))
1078     (select-window window)
1079     (goto-char pos))
1080   (let (node)
1081     (cond
1082      ((setq node (Info-get-token (point) "\\*note[ \n]" "\\*note[ \n]\\([^:]*\\):"))
1083       (Info-follow-reference node))
1084      ((setq node (Info-get-token (point) "\\* " "\\* \\([^:]*\\)::"))
1085       (Info-goto-node node))
1086      ((setq node (Info-get-token (point) "\\* " "\\* \\([^:]*\\):"))
1087       (Info-menu node))
1088      ((setq node (Info-get-token (point) "Up: " "Up: \\([^,\n\t]*\\)"))
1089       (Info-goto-node node))
1090      ((setq node (Info-get-token (point) "Next: " "Next: \\([^,\n\t]*\\)"))
1091       (Info-goto-node node))
1092      ((setq node (Info-get-token (point) "File: " "File: \\([^,\n\t]*\\)"))
1093       (Info-goto-node "Top"))
1094      ((setq node (Info-get-token (point) "Prev: " "Prev: \\([^,\n\t]*\\)"))
1095       (Info-goto-node node))
1096      ((save-excursion (forward-line 1) (eobp))
1097       (Info-next)))
1098     ))
1099 \f
1100 (defvar Info-mode-map nil
1101   "Keymap containing Info commands.")
1102 (if Info-mode-map
1103     nil
1104   (setq Info-mode-map (make-keymap))
1105   (suppress-keymap Info-mode-map)
1106   (define-key Info-mode-map "." 'beginning-of-buffer)
1107   (define-key Info-mode-map " " 'Info-scroll-up)
1108   (define-key Info-mode-map "\C-m" 'Info-next-preorder)
1109   (define-key Info-mode-map "1" 'Info-nth-menu-item)
1110   (define-key Info-mode-map "2" 'Info-nth-menu-item)
1111   (define-key Info-mode-map "3" 'Info-nth-menu-item)
1112   (define-key Info-mode-map "4" 'Info-nth-menu-item)
1113   (define-key Info-mode-map "5" 'Info-nth-menu-item)
1114   (define-key Info-mode-map "6" 'Info-nth-menu-item)
1115   (define-key Info-mode-map "7" 'Info-nth-menu-item)
1116   (define-key Info-mode-map "8" 'Info-nth-menu-item)
1117   (define-key Info-mode-map "9" 'Info-nth-menu-item)
1118   (define-key Info-mode-map "0" 'undefined)
1119   (define-key Info-mode-map "?" 'Info-summary)
1120   (define-key Info-mode-map "]" 'Info-forward-node)
1121   (define-key Info-mode-map "[" 'Info-backward-node)
1122   (define-key Info-mode-map "<" 'Info-top-node)
1123   (define-key Info-mode-map ">" 'Info-final-node)
1124   (define-key Info-mode-map "b" 'beginning-of-buffer)
1125   (define-key Info-mode-map "d" 'Info-directory)
1126   (define-key Info-mode-map "e" 'Info-edit)
1127   (define-key Info-mode-map "f" 'Info-follow-reference)
1128   (define-key Info-mode-map "g" 'Info-goto-node)
1129   (define-key Info-mode-map "h" 'Info-help)
1130   (define-key Info-mode-map "i" 'Info-index)
1131   (define-key Info-mode-map "l" 'Info-last)
1132   (define-key Info-mode-map "m" 'Info-menu)
1133   (define-key Info-mode-map "n" 'Info-next)
1134   (define-key Info-mode-map "p" 'Info-prev)
1135   (define-key Info-mode-map "q" 'Info-exit)
1136   (define-key Info-mode-map "s" 'Info-search)
1137   (define-key Info-mode-map "t" 'Info-top-node)
1138   (define-key Info-mode-map "u" 'Info-up)
1139   (define-key Info-mode-map "," 'Info-index-next)
1140   (define-key Info-mode-map "\177" 'Info-scroll-down)
1141   (define-key Info-mode-map [mouse-3] 'Info-follow-nearest-node)
1142   )
1143 \f
1144 ;; Info mode is suitable only for specially formatted data.
1145 (put 'info-mode 'mode-class 'special)
1146
1147 (defun Info-mode ()
1148   "\\<Info-mode-map>
1149 Info mode provides commands for browsing through the Info documentation tree.
1150 Documentation in Info is divided into \"nodes\", each of which discusses
1151 one topic and contains references to other nodes which discuss related
1152 topics.  Info has commands to follow the references and show you other nodes.
1153
1154 \\[Info-help]   Invoke the Info tutorial.
1155
1156 Selecting other nodes:
1157 \\[Info-next]   Move to the \"next\" node of this node.
1158 \\[Info-prev]   Move to the \"previous\" node of this node.
1159 \\[Info-up]     Move \"up\" from this node.
1160 \\[Info-menu]   Pick menu item specified by name (or abbreviation).
1161         Picking a menu item causes another node to be selected.
1162 \\[Info-directory]      Go to the Info directory node.
1163 \\[Info-follow-reference]       Follow a cross reference.  Reads name of reference.
1164 \\[Info-last]   Move to the last node you were at.
1165 \\[Info-index]  Look up a topic in this file's Index and move to that node.
1166 \\[Info-index-next]     (comma) Move to the next match from a previous `i' command.
1167
1168 Moving within a node:
1169 \\[scroll-up]   Normally, scroll forward a full screen.  If the end of the buffer is
1170 already visible, try to go to the next menu entry, or up if there is none.
1171 \\[scroll-down]  Normally, scroll backward.  If the beginning of the buffer is
1172 already visible, try to go to the previous menu entry, or up if there is none.
1173 \\[beginning-of-buffer] Go to beginning of node.
1174
1175 Advanced commands:
1176 \\[Info-exit]   Quit Info: reselect previously selected buffer.
1177 \\[Info-edit]   Edit contents of selected node.
1178 1       Pick first item in node's menu.
1179 2, 3, 4, 5   Pick second ... fifth item in node's menu.
1180 \\[Info-goto-node]      Move to node specified by name.
1181         You may include a filename as well, as (FILENAME)NODENAME.
1182 \\[Info-search] Search through this Info file for specified regexp,
1183         and select the node in which the next occurrence is found.
1184 \\[Info-next-preorder]  Next-preorder; that is, try to go to the next menu item,
1185         and if that fails try to move up, and if that fails, tell user
1186         he/she is done reading."
1187   (kill-all-local-variables)
1188   (setq major-mode 'Info-mode)
1189   (setq mode-name "Info")
1190   (use-local-map Info-mode-map)
1191   (set-syntax-table text-mode-syntax-table)
1192   (setq local-abbrev-table text-mode-abbrev-table)
1193   (setq case-fold-search t)
1194   (setq buffer-read-only t)
1195   (make-local-variable 'Info-current-file)
1196   (make-local-variable 'Info-current-subfile)
1197   (make-local-variable 'Info-current-node)
1198   (make-local-variable 'Info-tag-table-marker)
1199   (make-local-variable 'Info-history)
1200   (make-local-variable 'Info-index-alternatives)
1201   (Info-set-mode-line)
1202   (run-hooks 'Info-mode-hook))
1203
1204 (defvar Info-edit-map nil
1205   "Local keymap used within `e' command of Info.")
1206 (if Info-edit-map
1207     nil
1208   (setq Info-edit-map (nconc (make-sparse-keymap) text-mode-map))
1209   (define-key Info-edit-map "\C-c\C-c" 'Info-cease-edit))
1210
1211 ;; Info-edit mode is suitable only for specially formatted data.
1212 (put 'info-edit-mode 'mode-class 'special)
1213
1214 (defun Info-edit-mode ()
1215   "Major mode for editing the contents of an Info node.
1216 Like text mode with the addition of `Info-cease-edit'
1217 which returns to Info mode for browsing.
1218 \\{Info-edit-map}"
1219   )
1220
1221 (defun Info-edit ()
1222   "Edit the contents of this Info node.
1223 Allowed only if variable `Info-enable-edit' is non-nil."
1224   (interactive)
1225   (or Info-enable-edit
1226       (error "Editing info nodes is not enabled"))
1227   (use-local-map Info-edit-map)
1228   (setq major-mode 'Info-edit-mode)
1229   (setq mode-name "Info Edit")
1230   (kill-local-variable 'mode-line-buffer-identification)
1231   (setq buffer-read-only nil)
1232   ;; Make mode line update.
1233   (set-buffer-modified-p (buffer-modified-p))
1234   (message (substitute-command-keys
1235              "Editing: Type \\<Info-mode-map>\\[Info-cease-edit] to return to info")))
1236
1237 (defun Info-cease-edit ()
1238   "Finish editing Info node; switch back to Info proper."
1239   (interactive)
1240   ;; Do this first, so nothing has changed if user C-g's at query.
1241   (and (buffer-modified-p)
1242        (y-or-n-p "Save the file? ")
1243        (save-buffer))
1244   (use-local-map Info-mode-map)
1245   (setq major-mode 'Info-mode)
1246   (setq mode-name "Info")
1247   (Info-set-mode-line)
1248   (setq buffer-read-only t)
1249   ;; Make mode line update.
1250   (set-buffer-modified-p (buffer-modified-p))
1251   (and (marker-position Info-tag-table-marker)
1252        (buffer-modified-p)
1253        (message "Tags may have changed.  Use Info-tagify if necessary")))
1254 \f
1255 (defun Info-find-emacs-command-nodes (command)
1256   "Return a list of locations documenting COMMAND in the Emacs Info manual.
1257 The locations are of the format used in Info-history, i.e.
1258 \(FILENAME NODENAME BUFFERPOS\)."
1259   (require 'info)
1260   (let ((where '())
1261         (cmd-desc (concat "^\\* " (regexp-quote (symbol-name command))
1262                           ":\\s *\\(.*\\)\\.$")))
1263     (save-excursion
1264       (Info-find-node "emacs" "Command Index")
1265       ;; Take the index node off the Info history.
1266       (setq Info-history (cdr Info-history))
1267       (goto-char (point-max))
1268       (while (re-search-backward cmd-desc nil t)
1269           (setq where (cons (list Info-current-file
1270                                   (buffer-substring
1271                                    (match-beginning 1)
1272                                    (match-end 1))
1273                                   0)
1274                             where)))
1275       where)))
1276
1277 ;;;###autoload
1278 (defun Info-goto-emacs-command-node (command)
1279   "Go to the Info node in the Emacs manual for command COMMAND."
1280   (interactive "CFind documentation for command: ")
1281   (or (commandp command)
1282       (signal 'wrong-type-argument (list 'commandp command)))
1283   (let ((where (Info-find-emacs-command-nodes command)))
1284     (if where
1285         (let ((num-matches (length where)))
1286           ;; Get Info running, and pop to it in another window.
1287           (save-window-excursion
1288             (info))
1289           (pop-to-buffer "*info*")
1290           (Info-find-node (car (car where))
1291                           (car (cdr (car where))))
1292           (if (> num-matches 1)
1293               (progn
1294                 ;; Info-find-node already pushed (car where) onto
1295                 ;; Info-history.  Put the other nodes that were found on
1296                 ;; the history.
1297                 (setq Info-history (nconc (cdr where) Info-history))
1298                 (message (substitute-command-keys
1299                           "Found %d other entr%.  Use \\[Info-last] to see %s."
1300                         (1- num-matches)
1301                         (if (> num-matches 2) "ies" "y")
1302                         (if (> num-matches 2) "them" "it"))))))
1303       (error "Couldn't find documentation for %s." command))))
1304
1305 ;;;###autoload
1306 (defun Info-goto-emacs-key-command-node (key)
1307   "Go to the Info node in the Emacs manual the command bound to KEY, a string.
1308 Interactively, if the binding is execute-extended-command, a command is read."
1309   (interactive "kFind documentation for key:")
1310   (let ((command (key-binding key)))
1311     (cond ((null command)
1312            (message "%s is undefined" (key-description key)))
1313           ((and (interactive-p)
1314                 (eq command 'execute-extended-command))
1315            (Info-goto-emacs-command-node
1316             (read-command "Find documentation for command: ")))
1317           (t
1318            (Info-goto-emacs-command-node command)))))
1319
1320 (provide 'info)
1321
1322 ;;; info.el ends here