lisp/info.el

   1 ;;; info.el --- info package for Emacs.
   2
   3 ;; Copyright (C) 1985, 1986, 1992, 1993, 1994 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-fontify t
  51   "*Non-nil enables highlighting and fonts in Info nodes.")
  52
  53 (defvar Info-fontify-maximum-menu-size 30000
  54   "*Maximum size of menu to fontify if `Info-fontify' is non-nil.")
  55
  56 (defvar Info-directory-list
  57   (let ((path (getenv "INFOPATH"))
  58         ;; This is for older Emacs versions
  59         ;; which might get this info.el from the Texinfo distribution.
  60         (path-separator (if (boundp 'path-separator) path-separator
  61                           (if (eq system-type 'ms-dos) ";" ":")))
  62         (sibling (if installation-directory
  63                      (expand-file-name "info/" installation-directory))))
  64     (if path
  65         (let ((list nil)
  66               idx)
  67           (while (> (length path) 0)
  68             (setq idx (or (string-match path-separator path) (length path))
  69                   list (cons (substring path 0 idx) list)
  70                   path (substring path (min (1+ idx)
  71                                             (length path)))))
  72           (nreverse list))
  73       (if (or (null sibling)
  74               (member sibling Info-default-directory-list)
  75               (not (file-exists-p sibling))
  76               ;; On DOS/NT, we use movable executables always,
  77               ;; and we must always find the Info dir at run time.
  78               (if (or (eq system-type 'ms-dos) (eq system-type 'windows-nt))
  79                   nil
  80                 ;; Use invocation-directory for Info only if we used it for
  81                 ;; exec-directory also.
  82                 (not (string= exec-directory
  83                               (expand-file-name "lib-src/"
  84                                                 installation-directory)))))
  85           Info-default-directory-list
  86         (reverse (cons sibling (cdr (reverse Info-default-directory-list)))))))
  87   "List of directories to search for Info documentation files.
  88 nil means not yet initialized.  In this case, Info uses the environment
  89 variable INFOPATH to initialize it, or `Info-default-directory-list'
  90 if there is no INFOPATH variable in the environment.
  91 The last element of `Info-default-directory-list' is the directory
  92 where Emacs installs the Info files that come with it.
  93
  94 If you run the Emacs executable from the `src' directory in the Emacs
  95 source tree, the `info' directory in the source tree is used as the last
  96 element, in place of the installation Info directory.  This is useful
  97 when you run a version of Emacs without installing it.")
  98
  99 (defvar Info-additional-directory-list nil
 100   "List of additional directories to search for Info documentation files.
 101 These directories are not searched for merging the `dir' file.")
 102
 103 (defvar Info-current-file nil
 104   "Info file that Info is now looking at, or nil.")
 105
 106 (defvar Info-current-subfile nil
 107   "Info subfile that is actually in the *info* buffer now,
 108 or nil if current info file is not split into subfiles.")
 109
 110 (defvar Info-current-node nil
 111   "Name of node that Info is now looking at, or nil.")
 112
 113 (defvar Info-tag-table-marker (make-marker)
 114   "Marker pointing at beginning of current Info file's tag table.
 115 Marker points nowhere if file has no tag table.")
 116
 117 (defvar Info-current-file-completions nil
 118   "Cached completion list for current Info file.")
 119
 120 (defvar Info-index-alternatives nil
 121   "List of possible matches for last Info-index command.")
 122
 123 (defvar Info-standalone nil
 124   "Non-nil if Emacs was started solely as an Info browser.")
 125
 126 (defvar Info-suffix-list '( (".info.Z"  . "uncompress")
 127                             (".info.Y"  . "unyabba")
 128                             (".info.gz" . "gunzip")
 129                             (".info.z"  . "gunzip")
 130                             (".info"    . nil)
 131                             (".Z"       . "uncompress")
 132                             (".Y"       . "unyabba")
 133                             (".gz"      . "gunzip")
 134                             (".z"       . "gunzip")
 135                             (""         . nil))
 136   "List of file name suffixes and associated decoding commands.
 137 Each entry should be (SUFFIX . STRING); the file is given to
 138 the command as standard input.  If STRING is nil, no decoding is done.
 139 Because the SUFFIXes are tried in order, the empty string should
 140 be last in the list.")
 141
 142 (defun info-insert-file-contents (filename &optional visit)
 143   "Insert the contents of an info file in the current buffer.
 144 Do the right thing if the file has been compressed or zipped."
 145   (let ((tail Info-suffix-list)
 146         fullname decoder)
 147     (if (file-exists-p filename)
 148         (progn
 149           (while (and tail
 150                       (not (string-match
 151                             (concat (regexp-quote (car (car tail))) "$")
 152                             filename)))
 153             (setq tail (cdr tail)))
 154           (setq fullname filename
 155                 decoder (cdr (car tail))))
 156       (while (and tail
 157                   (not (file-exists-p (concat filename (car (car tail))))))
 158         (setq tail (cdr tail)))
 159       (setq fullname (concat filename (car (car tail)))
 160             decoder (cdr (car tail)))
 161       (or tail
 162           (error "Can't find %s or any compressed version of it!" filename)))
 163     ;; check for conflict with jka-compr
 164     (if (and (featurep 'jka-compr)
 165              (jka-compr-installed-p)
 166              (jka-compr-get-compression-info fullname))
 167         (setq decoder nil))
 168     (insert-file-contents fullname visit)
 169     (if decoder
 170         (let ((buffer-read-only nil)
 171               (default-directory (or (file-name-directory fullname)
 172                                      default-directory)))
 173           (shell-command-on-region (point-min) (point-max) decoder t)))))
 174
 175 ;;;###autoload (add-hook 'same-window-buffer-names "*info*")
 176
 177 ;;;###autoload
 178 (defun info (&optional file)
 179   "Enter Info, the documentation browser.
 180 Optional argument FILE specifies the file to examine;
 181 the default is the top-level directory of Info.
 182
 183 In interactive use, a prefix argument directs this command
 184 to read a file name from the minibuffer."
 185   (interactive (if current-prefix-arg
 186                    (list (read-file-name "Info file name: " nil nil t))))
 187   (if file
 188       (Info-goto-node (concat "(" file ")"))
 189     (if (get-buffer "*info*")
 190         (pop-to-buffer "*info*")
 191       (Info-directory))))
 192
 193 ;;;###autoload
 194 (defun info-standalone ()
 195   "Run Emacs as a standalone Info reader.
 196 Usage:  emacs -f info-standalone [filename]
 197 In standalone mode, \\<Info-mode-map>\\[Info-exit] exits Emacs itself."
 198   (setq Info-standalone t)
 199   (if (and command-line-args-left
 200            (not (string-match "^-" (car command-line-args-left))))
 201       (condition-case err
 202           (progn
 203             (info (car command-line-args-left))
 204             (setq command-line-args-left (cdr command-line-args-left)))
 205         (error (send-string-to-terminal
 206                 (format "%s\n" (if (eq (car-safe err) 'error)
 207                                    (nth 1 err) err)))
 208                (save-buffers-kill-emacs)))
 209     (info)))
 210
 211 ;; Go to an info node specified as separate filename and nodename.
 212 ;; no-going-back is non-nil if recovering from an error in this function;
 213 ;; it says do not attempt further (recursive) error recovery.
 214 (defun Info-find-node (filename nodename &optional no-going-back)
 215   ;; Convert filename to lower case if not found as specified.
 216   ;; Expand it.
 217   (if filename
 218       (let (temp temp-downcase found)
 219         (setq filename (substitute-in-file-name filename))
 220         (if (string= (downcase (file-name-nondirectory filename)) "dir")
 221             (setq found t)
 222           (let ((dirs (if (string-match "^\\./" filename)
 223                           ;; If specified name starts with `./'
 224                           ;; then just try current directory.
 225                           '("./")
 226                         (if (file-name-absolute-p filename)
 227                             ;; No point in searching for an
 228                             ;; absolute file name
 229                             '(nil)
 230                           (if Info-additional-directory-list
 231                               (append Info-directory-list
 232                                       Info-additional-directory-list)
 233                             Info-directory-list)))))
 234             ;; Search the directory list for file FILENAME.
 235             (while (and dirs (not found))
 236               (setq temp (expand-file-name filename (car dirs)))
 237               (setq temp-downcase
 238                     (expand-file-name (downcase filename) (car dirs)))
 239               ;; Try several variants of specified name.
 240               (let ((suffix-list Info-suffix-list))
 241                 (while (and suffix-list (not found))
 242                   (cond ((file-exists-p
 243                           (concat temp (car (car suffix-list))))
 244                          (setq found temp))
 245                         ((file-exists-p
 246                           (concat temp-downcase (car (car suffix-list))))
 247                          (setq found temp-downcase)))
 248                   (setq suffix-list (cdr suffix-list))))
 249               (setq dirs (cdr dirs)))))
 250         (if found
 251             (setq filename found)
 252           (error "Info file %s does not exist" filename))))
 253   ;; Record the node we are leaving.
 254   (if (and Info-current-file (not no-going-back))
 255       (setq Info-history
 256             (cons (list Info-current-file Info-current-node (point))
 257                   Info-history)))
 258   ;; Go into info buffer.
 259   (switch-to-buffer "*info*")
 260   (buffer-disable-undo (current-buffer))
 261   (or (eq major-mode 'Info-mode)
 262       (Info-mode))
 263   (widen)
 264   (setq Info-current-node nil)
 265   (unwind-protect
 266       (progn
 267         ;; Switch files if necessary
 268         (or (null filename)
 269             (equal Info-current-file filename)
 270             (let ((buffer-read-only nil))
 271               (setq Info-current-file nil
 272                     Info-current-subfile nil
 273                     Info-current-file-completions nil
 274                     Info-index-alternatives nil
 275                     buffer-file-name nil)
 276               (erase-buffer)
 277               (if (eq filename t)
 278                   (Info-insert-dir)
 279                 (info-insert-file-contents filename t)
 280                 (setq default-directory (file-name-directory filename)))
 281               (set-buffer-modified-p nil)
 282               ;; See whether file has a tag table.  Record the location if yes.
 283               (set-marker Info-tag-table-marker nil)
 284               (goto-char (point-max))
 285               (forward-line -8)
 286               ;; Use string-equal, not equal, to ignore text props.
 287               (or (string-equal nodename "*")
 288                   (not (search-forward "\^_\nEnd tag table\n" nil t))
 289                   (let (pos)
 290                     ;; We have a tag table.  Find its beginning.
 291                     ;; Is this an indirect file?
 292                     (search-backward "\nTag table:\n")
 293                     (setq pos (point))
 294                     (if (save-excursion
 295                           (forward-line 2)
 296                           (looking-at "(Indirect)\n"))
 297                         ;; It is indirect.  Copy it to another buffer
 298                         ;; and record that the tag table is in that buffer.
 299                         (save-excursion
 300                           (let ((buf (current-buffer)))
 301                             (set-buffer (get-buffer-create " *info tag table*"))
 302                             (buffer-disable-undo (current-buffer))
 303                             (setq case-fold-search t)
 304                             (erase-buffer)
 305                             (insert-buffer-substring buf)
 306                             (set-marker Info-tag-table-marker
 307                                         (match-end 0))))
 308                       (set-marker Info-tag-table-marker pos))))
 309               (setq Info-current-file
 310                     (if (eq filename t) "dir"
 311                       (file-name-sans-versions buffer-file-name)))))
 312         ;; Use string-equal, not equal, to ignore text props.
 313         (if (string-equal nodename "*")
 314             (progn (setq Info-current-node nodename)
 315                    (Info-set-mode-line))
 316           ;; Search file for a suitable node.
 317           (let ((guesspos (point-min))
 318                 (regexp (concat "Node: *" (regexp-quote nodename) " *[,\t\n\177]")))
 319             ;; First get advice from tag table if file has one.
 320             ;; Also, if this is an indirect info file,
 321             ;; read the proper subfile into this buffer.
 322             (if (marker-position Info-tag-table-marker)
 323                 (save-excursion
 324                   (set-buffer (marker-buffer Info-tag-table-marker))
 325                   (goto-char Info-tag-table-marker)
 326                   (if (re-search-forward regexp nil t)
 327                       (progn
 328                         (setq guesspos (read (current-buffer)))
 329                         ;; If this is an indirect file,
 330                         ;; determine which file really holds this node
 331                         ;; and read it in.
 332                         (if (not (eq (current-buffer) (get-buffer "*info*")))
 333                             (setq guesspos
 334                                   (Info-read-subfile guesspos))))
 335                     (error "No such node: \"%s\"" nodename))))
 336             (goto-char (max (point-min) (- guesspos 1000)))
 337             ;; Now search from our advised position (or from beg of buffer)
 338             ;; to find the actual node.
 339             (catch 'foo
 340               (while (search-forward "\n\^_" nil t)
 341                 (forward-line 1)
 342                 (let ((beg (point)))
 343                   (forward-line 1)
 344                   (if (re-search-backward regexp beg t)
 345                       (throw 'foo t))))
 346               (error "No such node: %s" nodename)))
 347           (Info-select-node)))
 348     ;; If we did not finish finding the specified node,
 349     ;; go back to the previous one.
 350     (or Info-current-node no-going-back (null Info-history)
 351         (let ((hist (car Info-history)))
 352           (setq Info-history (cdr Info-history))
 353           (Info-find-node (nth 0 hist) (nth 1 hist) t)
 354           (goto-char (nth 2 hist)))))
 355   (goto-char (point-min)))
 356
 357 ;; Cache the contents of the (virtual) dir file, once we have merged
 358 ;; it for the first time, so we can save time subsequently.
 359 (defvar Info-dir-contents nil)
 360
 361 ;; Cache for the directory we decided to use for the default-directory
 362 ;; of the merged dir text.
 363 (defvar Info-dir-contents-directory nil)
 364
 365 ;; Record the file attributes of all the files from which we
 366 ;; constructed Info-dir-contents.
 367 (defvar Info-dir-file-attributes nil)
 368
 369 ;; Construct the Info directory node by merging the files named `dir'
 370 ;; from various directories.  Set the *info* buffer's
 371 ;; default-directory to the first directory we actually get any text
 372 ;; from.
 373 (defun Info-insert-dir ()
 374   (if (and Info-dir-contents Info-dir-file-attributes
 375            ;; Verify that none of the files we used has changed
 376            ;; since we used it.
 377            (eval (cons 'and
 378                        (mapcar '(lambda (elt)
 379                                   (let ((curr (file-attributes (car elt))))
 380                                     ;; Don't compare the access time.
 381                                     (if curr (setcar (nthcdr 4 curr) 0))
 382                                     (setcar (nthcdr 4 (cdr elt)) 0)
 383                                     (equal (cdr elt) curr)))
 384                                Info-dir-file-attributes))))
 385       (insert Info-dir-contents)
 386     (let ((dirs Info-directory-list)
 387           buffers buffer others nodes dirs-done)
 388
 389       (setq Info-dir-file-attributes nil)
 390
 391       ;; Search the directory list for the directory file.
 392       (while dirs
 393         (let ((truename (file-truename (expand-file-name (car dirs)))))
 394           (or (member truename dirs-done)
 395               (member (directory-file-name truename) dirs-done)
 396               ;; Try several variants of specified name.
 397               ;; Try upcasing, appending `.info', or both.
 398               (let* (file
 399                      (attrs
 400                       (or
 401                        (progn (setq file (expand-file-name "dir" truename))
 402                               (file-attributes file))
 403                        (progn (setq file (expand-file-name "DIR" truename))
 404                               (file-attributes file))
 405                        (progn (setq file (expand-file-name "dir.info" truename))
 406                               (file-attributes file))
 407                        (progn (setq file (expand-file-name "DIR.INFO" truename))
 408                               (file-attributes file)))))
 409                 (setq dirs-done
 410                       (cons truename
 411                             (cons (directory-file-name truename)
 412                                   dirs-done)))
 413                 (if attrs
 414                     (save-excursion
 415                       (or buffers
 416                           (message "Composing main Info directory..."))
 417                       (set-buffer (generate-new-buffer "info dir"))
 418                       (insert-file-contents file)
 419                       (setq buffers (cons (current-buffer) buffers)
 420                             Info-dir-file-attributes
 421                             (cons (cons file attrs)
 422                                   Info-dir-file-attributes))))))
 423           (setq dirs (cdr dirs))))
 424
 425       (or buffers
 426           (error "Can't find the info directory node"))
 427       ;; Distinguish the dir file that comes with Emacs from all the
 428       ;; others.  Yes, that is really what this is supposed to do.
 429       ;; If it doesn't work, fix it.
 430       (setq buffer (car buffers)
 431             others (cdr buffers))
 432
 433       ;; Insert the entire original dir file as a start; use its
 434       ;; default directory as the default directory for the whole
 435       ;; concatenation.
 436       (insert-buffer buffer)
 437       (setq Info-dir-contents-directory (save-excursion
 438                                           (set-buffer buffer)
 439                                           default-directory))
 440
 441       ;; Look at each of the other buffers one by one.
 442       (while others
 443         (let ((other (car others)))
 444           ;; In each, find all the menus.
 445           (save-excursion
 446             (set-buffer other)
 447             (goto-char (point-min))
 448             ;; Find each menu, and add an elt to NODES for it.
 449             (while (re-search-forward "^\\* Menu:" nil t)
 450               (let (beg nodename end)
 451                 (forward-line 1)
 452                 (setq beg (point))
 453                 (search-backward "\n\^_")
 454                 (search-forward "Node: ")
 455                 (setq nodename (Info-following-node-name))
 456                 (search-forward "\n\^_" nil 'move)
 457                 (beginning-of-line)
 458                 (setq end (point))
 459                 (setq nodes (cons (list nodename other beg end) nodes))))))
 460         (setq others (cdr others)))
 461       ;; Add to the main menu a menu item for each other node.
 462       (re-search-forward "^\\* Menu:")
 463       (forward-line 1)
 464       (let ((menu-items '("top"))
 465             (nodes nodes)
 466             (case-fold-search t)
 467             (end (save-excursion (search-forward "\^_" nil t) (point))))
 468         (while nodes
 469           (let ((nodename (car (car nodes))))
 470             (save-excursion
 471               (or (member (downcase nodename) menu-items)
 472                   (re-search-forward (concat "^\\* "
 473                                              (regexp-quote nodename)
 474                                              "::")
 475                                      end t)
 476                   (progn
 477                     (insert "* " nodename "::" "\n")
 478                     (setq menu-items (cons nodename menu-items))))))
 479           (setq nodes (cdr nodes))))
 480       ;; Now take each node of each of the other buffers
 481       ;; and merge it into the main buffer.
 482       (while nodes
 483         (let ((nodename (car (car nodes))))
 484           (goto-char (point-min))
 485           ;; Find the like-named node in the main buffer.
 486           (if (re-search-forward (concat "\n\^_.*\n.*Node: "
 487                                          (regexp-quote nodename)
 488                                          "[,\n\t]")
 489                                  nil t)
 490               (progn
 491                 (search-forward "\n\^_" nil 'move)
 492                 (beginning-of-line)
 493                 (insert "\n"))
 494             ;; If none exists, add one.
 495             (goto-char (point-max))
 496             (insert "\^_\nFile: dir\tNode: " nodename "\n\n* Menu:\n\n"))
 497           ;; Merge the text from the other buffer's menu
 498           ;; into the menu in the like-named node in the main buffer.
 499           (apply 'insert-buffer-substring (cdr (car nodes))))
 500         (setq nodes (cdr nodes)))
 501       ;; Kill all the buffers we just made.
 502       (while buffers
 503         (kill-buffer (car buffers))
 504         (setq buffers (cdr buffers)))
 505       (message "Composing main Info directory...done"))
 506     (setq Info-dir-contents (buffer-string)))
 507   (setq default-directory Info-dir-contents-directory))
 508
 509 (defun Info-read-subfile (nodepos)
 510   (set-buffer (marker-buffer Info-tag-table-marker))
 511   (goto-char (point-min))
 512   (search-forward "\n\^_")
 513   (let (lastfilepos
 514         lastfilename)
 515     (forward-line 2)
 516     (catch 'foo
 517       (while (not (looking-at "\^_"))
 518         (if (not (eolp))
 519             (let ((beg (point))
 520                   thisfilepos thisfilename)
 521               (search-forward ": ")
 522               (setq thisfilename  (buffer-substring beg (- (point) 2)))
 523               (setq thisfilepos (read (current-buffer)))
 524               ;; read in version 19 stops at the end of number.
 525               ;; Advance to the next line.
 526               (forward-line 1)
 527               (if (> thisfilepos nodepos)
 528                   (throw 'foo t))
 529               (setq lastfilename thisfilename)
 530               (setq lastfilepos thisfilepos))
 531           (forward-line 1))))
 532     (set-buffer (get-buffer "*info*"))
 533     (or (equal Info-current-subfile lastfilename)
 534         (let ((buffer-read-only nil))
 535           (setq buffer-file-name nil)
 536           (widen)
 537           (erase-buffer)
 538           (info-insert-file-contents lastfilename)
 539           (set-buffer-modified-p nil)
 540           (setq Info-current-subfile lastfilename)))
 541     (goto-char (point-min))
 542     (search-forward "\n\^_")
 543     (+ (- nodepos lastfilepos) (point))))
 544
 545 ;; Select the info node that point is in.
 546 (defun Info-select-node ()
 547   (save-excursion
 548    ;; Find beginning of node.
 549    (search-backward "\n\^_")
 550    (forward-line 2)
 551    ;; Get nodename spelled as it is in the node.
 552    (re-search-forward "Node:[ \t]*")
 553    (setq Info-current-node
 554          (buffer-substring (point)
 555                            (progn
 556                             (skip-chars-forward "^,\t\n")
 557                             (point))))
 558    (Info-set-mode-line)
 559    ;; Find the end of it, and narrow.
 560    (beginning-of-line)
 561    (let (active-expression)
 562      (narrow-to-region (point)
 563                        (if (re-search-forward "\n[\^_\f]" nil t)
 564                            (prog1
 565                             (1- (point))
 566                             (if (looking-at "[\n\^_\f]*execute: ")
 567                                 (progn
 568                                   (goto-char (match-end 0))
 569                                   (setq active-expression
 570                                         (read (current-buffer))))))
 571                          (point-max)))
 572      (if Info-enable-active-nodes (eval active-expression))
 573      (if Info-fontify (Info-fontify-node))
 574      (run-hooks 'Info-selection-hook))))
 575
 576 (defun Info-set-mode-line ()
 577   (setq mode-line-buffer-identification
 578         (concat
 579          "Info:  ("
 580          (if Info-current-file
 581              (file-name-nondirectory Info-current-file)
 582            "")
 583          ")"
 584          (or Info-current-node ""))))
 585 \f
 586 ;; Go to an info node specified with a filename-and-nodename string
 587 ;; of the sort that is found in pointers in nodes.
 588
 589 (defun Info-goto-node (nodename)
 590   "Go to info node named NAME.  Give just NODENAME or (FILENAME)NODENAME."
 591   (interactive (list (Info-read-node-name "Goto node: ")))
 592   (let (filename)
 593     (string-match "\\s *\\((\\s *\\([^\t)]*\\)\\s *)\\s *\\|\\)\\(.*\\)"
 594                   nodename)
 595     (setq filename (if (= (match-beginning 1) (match-end 1))
 596                        ""
 597                      (substring nodename (match-beginning 2) (match-end 2)))
 598           nodename (substring nodename (match-beginning 3) (match-end 3)))
 599     (let ((trim (string-match "\\s *\\'" filename)))
 600       (if trim (setq filename (substring filename 0 trim))))
 601     (let ((trim (string-match "\\s *\\'" nodename)))
 602       (if trim (setq nodename (substring nodename 0 trim))))
 603     (Info-find-node (if (equal filename "") nil filename)
 604                     (if (equal nodename "") "Top" nodename))))
 605
 606 (defun Info-read-node-name (prompt &optional default)
 607   (let* ((completion-ignore-case t)
 608          (nodename (completing-read prompt (Info-build-node-completions))))
 609     (if (equal nodename "")
 610         (or default
 611             (Info-read-node-name prompt))
 612       nodename)))
 613
 614 (defun Info-build-node-completions ()
 615   (or Info-current-file-completions
 616       (let ((compl nil))
 617         (save-excursion
 618           (save-restriction
 619             (if (marker-buffer Info-tag-table-marker)
 620                 (progn
 621                   (set-buffer (marker-buffer Info-tag-table-marker))
 622                   (widen)
 623                   (goto-char Info-tag-table-marker)
 624                   (while (re-search-forward "\nNode: \\(.*\\)\177" nil t)
 625                     (setq compl
 626                           (cons (list (buffer-substring (match-beginning 1)
 627                                                         (match-end 1)))
 628                                 compl))))
 629               (widen)
 630               (goto-char (point-min))
 631               (while (search-forward "\n\^_" nil t)
 632                 (forward-line 1)
 633                 (let ((beg (point)))
 634                   (forward-line 1)
 635                   (if (re-search-backward "Node: *\\([^,\n]*\\) *[,\n\t]"
 636                                           beg t)
 637                       (setq compl
 638                             (cons (list (buffer-substring (match-beginning 1)
 639                                                           (match-end 1)))
 640                                   compl))))))))
 641         (setq Info-current-file-completions compl))))
 642 \f
 643 (defun Info-restore-point (hl)
 644   "If this node has been visited, restore the point value when we left."
 645   (while hl
 646     (if (and (equal (nth 0 (car hl)) Info-current-file)
 647              ;; Use string-equal, not equal, to ignore text props.
 648              (string-equal (nth 1 (car hl)) Info-current-node))
 649         (progn
 650           (goto-char (nth 2 (car hl)))
 651           (setq hl nil))                ;terminate the while at next iter
 652       (setq hl (cdr hl)))))
 653 \f
 654 (defvar Info-last-search nil
 655   "Default regexp for \\<Info-mode-map>\\[Info-search] command to search for.")
 656
 657 (defun Info-search (regexp)
 658   "Search for REGEXP, starting from point, and select node it's found in."
 659   (interactive "sSearch (regexp): ")
 660   (if (equal regexp "")
 661       (setq regexp Info-last-search)
 662     (setq Info-last-search regexp))
 663   (let ((found ()) current
 664         (onode Info-current-node)
 665         (ofile Info-current-file)
 666         (opoint (point))
 667         (osubfile Info-current-subfile))
 668     (save-excursion
 669       (save-restriction
 670         (widen)
 671         (if (null Info-current-subfile)
 672             (progn (re-search-forward regexp) (setq found (point)))
 673           (condition-case err
 674               (progn (re-search-forward regexp) (setq found (point)))
 675             (search-failed nil)))))
 676     (if (not found) ;can only happen in subfile case -- else would have erred
 677         (unwind-protect
 678             (let ((list ()))
 679               (set-buffer (marker-buffer Info-tag-table-marker))
 680               (goto-char (point-min))
 681               (search-forward "\n\^_\nIndirect:")
 682               (save-restriction
 683                 (narrow-to-region (point)
 684                                   (progn (search-forward "\n\^_")
 685                                          (1- (point))))
 686                 (goto-char (point-min))
 687                 (search-forward (concat "\n" osubfile ": "))
 688                 (beginning-of-line)
 689                 (while (not (eobp))
 690                   (re-search-forward "\\(^.*\\): [0-9]+$")
 691                   (goto-char (+ (match-end 1) 2))
 692                   (setq list (cons (cons (read (current-buffer))
 693                                          (buffer-substring (match-beginning 1)
 694                                                            (match-end 1)))
 695                                    list))
 696                   (goto-char (1+ (match-end 0))))
 697                 (setq list (nreverse list)
 698                       current (car (car list))
 699                       list (cdr list)))
 700               (while list
 701                 (message "Searching subfile %s..." (cdr (car list)))
 702                 (Info-read-subfile (car (car list)))
 703                 (setq list (cdr list))
 704 ;;              (goto-char (point-min))
 705                 (if (re-search-forward regexp nil t)
 706                     (setq found (point) list ())))
 707               (if found
 708                   (message "")
 709                 (signal 'search-failed (list regexp))))
 710           (if (not found)
 711               (progn (Info-read-subfile opoint)
 712                      (goto-char opoint)
 713                      (Info-select-node)))))
 714     (widen)
 715     (goto-char found)
 716     (Info-select-node)
 717     ;; Use string-equal, not equal, to ignore text props.
 718     (or (and (string-equal onode Info-current-node)
 719              (equal ofile Info-current-file))
 720         (setq Info-history (cons (list ofile onode opoint)
 721                                  Info-history)))))
 722 \f
 723 ;; Extract the value of the node-pointer named NAME.
 724 ;; If there is none, use ERRORNAME in the error message;
 725 ;; if ERRORNAME is nil, just return nil.
 726 (defun Info-extract-pointer (name &optional errorname)
 727   (save-excursion
 728    (goto-char (point-min))
 729    (forward-line 1)
 730    (if (re-search-backward (concat name ":") nil t)
 731        (progn
 732          (goto-char (match-end 0))
 733          (Info-following-node-name))
 734      (if (eq errorname t)
 735          nil
 736        (error (concat "Node has no " (capitalize (or errorname name))))))))
 737
 738 ;; Return the node name in the buffer following point.
 739 ;; ALLOWEDCHARS, if non-nil, goes within [...] to make a regexp
 740 ;; saying which chas may appear in the node name.
 741 (defun Info-following-node-name (&optional allowedchars)
 742   (skip-chars-forward " \t")
 743   (buffer-substring
 744    (point)
 745    (progn
 746      (while (looking-at (concat "[" (or allowedchars "^,\t\n") "]"))
 747        (skip-chars-forward (concat (or allowedchars "^,\t\n") "("))
 748        (if (looking-at "(")
 749            (skip-chars-forward "^)")))
 750      (skip-chars-backward " ")
 751      (point))))
 752
 753 (defun Info-next ()
 754   "Go to the next node of this node."
 755   (interactive)
 756   (Info-goto-node (Info-extract-pointer "next")))
 757
 758 (defun Info-prev ()
 759   "Go to the previous node of this node."
 760   (interactive)
 761   (Info-goto-node (Info-extract-pointer "prev[ious]*" "previous")))
 762
 763 (defun Info-up ()
 764   "Go to the superior node of this node."
 765   (interactive)
 766   (Info-goto-node (Info-extract-pointer "up"))
 767   (Info-restore-point Info-history))
 768
 769 (defun Info-last ()
 770   "Go back to the last node visited."
 771   (interactive)
 772   (or Info-history
 773       (error "This is the first Info node you looked at"))
 774   (let (filename nodename opoint)
 775     (setq filename (car (car Info-history)))
 776     (setq nodename (car (cdr (car Info-history))))
 777     (setq opoint (car (cdr (cdr (car Info-history)))))
 778     (setq Info-history (cdr Info-history))
 779     (Info-find-node filename nodename)
 780     (setq Info-history (cdr Info-history))
 781     (goto-char opoint)))
 782
 783 (defun Info-directory ()
 784   "Go to the Info directory node."
 785   (interactive)
 786   (Info-find-node "dir" "top"))
 787 \f
 788 (defun Info-follow-reference (footnotename)
 789   "Follow cross reference named NAME to the node it refers to.
 790 NAME may be an abbreviation of the reference name."
 791   (interactive
 792    (let ((completion-ignore-case t)
 793          completions default alt-default (start-point (point)) str i bol eol)
 794      (save-excursion
 795        ;; Store end and beginning of line.
 796        (end-of-line)
 797        (setq eol (point))
 798        (beginning-of-line)
 799        (setq bol (point))
 800
 801        (goto-char (point-min))
 802        (while (re-search-forward "\\*note[ \n\t]*\\([^:]*\\):" nil t)
 803          (setq str (buffer-substring
 804                     (match-beginning 1)
 805                     (1- (point))))
 806          ;; See if this one should be the default.
 807          (and (null default)
 808               (<= (match-beginning 0) start-point)
 809               (<= start-point (point))
 810               (setq default t))
 811          ;; See if this one should be the alternate default.
 812          (and (null alt-default)
 813               (and (<= bol (match-beginning 0))
 814                    (<= (point) eol))
 815               (setq alt-default t))
 816          (setq i 0)
 817          (while (setq i (string-match "[ \n\t]+" str i))
 818            (setq str (concat (substring str 0 i) " "
 819                              (substring str (match-end 0))))
 820            (setq i (1+ i)))
 821          ;; Record as a completion and perhaps as default.
 822          (if (eq default t) (setq default str))
 823          (if (eq alt-default t) (setq alt-default str))
 824          (setq completions
 825                (cons (cons str nil)
 826                      completions))))
 827      ;; If no good default was found, try an alternate.
 828      (or default
 829          (setq default alt-default))
 830      ;; If only one cross-reference found, then make it default.
 831      (if (eq (length completions) 1)
 832          (setq default (car (car completions))))
 833      (if completions
 834          (let ((input (completing-read (if default
 835                                            (concat "Follow reference named: ("
 836                                                    default ") ")
 837                                          "Follow reference named: ")
 838                                        completions nil t)))
 839            (list (if (equal input "")
 840                      default input)))
 841        (error "No cross-references in this node"))))
 842   (let (target beg i (str (concat "\\*note " (regexp-quote footnotename))))
 843     (while (setq i (string-match " " str i))
 844       (setq str (concat (substring str 0 i) "[ \t\n]+" (substring str (1+ i))))
 845       (setq i (+ i 6)))
 846     (save-excursion
 847       (goto-char (point-min))
 848       (or (re-search-forward str nil t)
 849           (error "No cross-reference named %s" footnotename))
 850       (goto-char (+ (match-beginning 0) 5))
 851       (setq target
 852             (Info-extract-menu-node-name "Bad format cross reference" t)))
 853     (while (setq i (string-match "[ \t\n]+" target i))
 854       (setq target (concat (substring target 0 i) " "
 855                            (substring target (match-end 0))))
 856       (setq i (+ i 1)))
 857     (Info-goto-node target)))
 858
 859 (defun Info-extract-menu-node-name (&optional errmessage multi-line)
 860   (skip-chars-forward " \t\n")
 861   (let ((beg (point))
 862         str i)
 863     (skip-chars-forward "^:")
 864     (forward-char 1)
 865     (setq str
 866           (if (looking-at ":")
 867               (buffer-substring beg (1- (point)))
 868             (skip-chars-forward " \t\n")
 869             (Info-following-node-name (if multi-line "^.,\t" "^.,\t\n"))))
 870     (while (setq i (string-match "\n" str i))
 871       (aset str i ?\ ))
 872     ;; Collapse multiple spaces.
 873     (while (string-match "  +" str)
 874       (setq str (replace-match " " t t str)))
 875     str))
 876
 877 ;; No one calls this.
 878 ;;(defun Info-menu-item-sequence (list)
 879 ;;  (while list
 880 ;;    (Info-menu (car list))
 881 ;;    (setq list (cdr list))))
 882
 883 (defun Info-complete-menu-item (string predicate action)
 884   (let ((case-fold-search t))
 885     (cond ((eq action nil)
 886            (let (completions
 887                  (pattern (concat "\n\\* \\("
 888                                   (regexp-quote string)
 889                                   "[^:\t\n]*\\):")))
 890              (save-excursion
 891                (set-buffer Info-complete-menu-buffer)
 892                (goto-char (point-min))
 893                (while (re-search-forward pattern nil t)
 894                  (setq completions (cons (cons (format "%s"
 895                                                        (buffer-substring
 896                                                         (match-beginning 1)
 897                                                         (match-end 1)))
 898                                                (match-beginning 1))
 899                                          completions))))
 900              (try-completion string completions predicate)))
 901           ((eq action t)
 902            (let (completions
 903                  (pattern (concat "\n\\* \\("
 904                                   (regexp-quote string)
 905                                   "[^:\t\n]*\\):")))
 906              (save-excursion
 907                (set-buffer Info-complete-menu-buffer)
 908                (goto-char (point-min))
 909                (while (re-search-forward pattern nil t)
 910                  (setq completions (cons (cons (format "%s"
 911                                                        (buffer-substring
 912                                                         (match-beginning 1)
 913                                                         (match-end 1)))
 914                                                (match-beginning 1))
 915                                          completions))))
 916              (all-completions string completions predicate)))
 917           (t
 918            (save-excursion
 919              (set-buffer Info-complete-menu-buffer)
 920              (goto-char (point-min))
 921              (re-search-forward (concat "\n\\* "
 922                                         (regexp-quote string)
 923                                         ":")
 924                                 nil t))))))
 925
 926
 927 (defun Info-menu (menu-item)
 928   "Go to node for menu item named (or abbreviated) NAME.
 929 Completion is allowed, and the menu item point is on is the default."
 930   (interactive
 931    (let ((completions '())
 932          ;; If point is within a menu item, use that item as the default
 933          (default nil)
 934          (p (point))
 935          beg
 936          (last nil))
 937      (save-excursion
 938        (goto-char (point-min))
 939        (if (not (search-forward "\n* menu:" nil t))
 940            (error "No menu in this node"))
 941        (setq beg (point))
 942        (and (< (point) p)
 943             (save-excursion
 944               (goto-char p)
 945               (end-of-line)
 946               (re-search-backward "\n\\* \\([^:\t\n]*\\):" beg t)
 947               (setq default (format "%s" (buffer-substring
 948                                           (match-beginning 1)
 949                                           (match-end 1)))))))
 950      (let ((item nil))
 951        (while (null item)
 952          (setq item (let ((completion-ignore-case t)
 953                           (Info-complete-menu-buffer (current-buffer)))
 954                       (completing-read (if default
 955                                            (format "Menu item (default %s): "
 956                                                    default)
 957                                            "Menu item: ")
 958                                        'Info-complete-menu-item nil t)))
 959          ;; we rely on the fact that completing-read accepts an input
 960          ;; of "" even when the require-match argument is true and ""
 961          ;; is not a valid possibility
 962          (if (string= item "")
 963              (if default
 964                  (setq item default)
 965                  ;; ask again
 966                  (setq item nil))))
 967        (list item))))
 968   ;; there is a problem here in that if several menu items have the same
 969   ;; name you can only go to the node of the first with this command.
 970   (Info-goto-node (Info-extract-menu-item menu-item)))
 971
 972 (defun Info-extract-menu-item (menu-item)
 973   (setq menu-item (regexp-quote menu-item))
 974   (save-excursion
 975     (goto-char (point-min))
 976     (or (search-forward "\n* menu:" nil t)
 977         (error "No menu in this node"))
 978     (or (re-search-forward (concat "\n\\* " menu-item ":") nil t)
 979         (re-search-forward (concat "\n\\* " menu-item) nil t)
 980         (error "No such item in menu"))
 981     (beginning-of-line)
 982     (forward-char 2)
 983     (Info-extract-menu-node-name)))
 984
 985 ;; If COUNT is nil, use the last item in the menu.
 986 (defun Info-extract-menu-counting (count)
 987   (save-excursion
 988     (goto-char (point-min))
 989     (or (search-forward "\n* menu:" nil t)
 990         (error "No menu in this node"))
 991     (if count
 992         (or (search-forward "\n* " nil t count)
 993             (error "Too few items in menu"))
 994       (while (search-forward "\n* " nil t)
 995         nil))
 996     (Info-extract-menu-node-name)))
 997
 998 (defun Info-nth-menu-item ()
 999   "Go to the node of the Nth menu item.
1000 N is the digit argument used to invoke this command."
1001   (interactive)
1002   (Info-goto-node
1003    (Info-extract-menu-counting
1004     (- (aref (this-command-keys) (1- (length (this-command-keys)))) ?0))))
1005
1006 (defun Info-top-node ()
1007   "Go to the Top node of this file."
1008   (interactive)
1009   (Info-goto-node "Top"))
1010
1011 (defun Info-final-node ()
1012   "Go to the final node in this file."
1013   (interactive)
1014   (Info-goto-node "Top")
1015   (let (Info-history)
1016     ;; Go to the last node in the menu of Top.
1017     (Info-goto-node (Info-extract-menu-counting nil))
1018     ;; If the last node in the menu is not last in pointer structure,
1019     ;; move forward until we can't go any farther.
1020     (while (Info-forward-node t t) nil)
1021     ;; Then keep moving down to last subnode, unless we reach an index.
1022     (while (and (not (string-match "\\<index\\>" Info-current-node))
1023                 (save-excursion (search-forward "\n* Menu:" nil t)))
1024       (Info-goto-node (Info-extract-menu-counting nil)))))
1025
1026 (defun Info-forward-node (&optional not-down no-error)
1027   "Go forward one node, considering all nodes as forming one sequence."
1028   (interactive)
1029   (goto-char (point-min))
1030   (forward-line 1)
1031   ;; three possibilities, in order of priority:
1032   ;;     1. next node is in a menu in this node (but not in an index)
1033   ;;     2. next node is next at same level
1034   ;;     3. next node is up and next
1035   (cond ((and (not not-down)
1036               (save-excursion (search-forward "\n* menu:" nil t))
1037               (not (string-match "\\<index\\>" Info-current-node)))
1038          (Info-goto-node (Info-extract-menu-counting 1))
1039          t)
1040         ((save-excursion (search-backward "next:" nil t))
1041          (Info-next)
1042          t)
1043         ((and (save-excursion (search-backward "up:" nil t))
1044               ;; Use string-equal, not equal, to ignore text props.
1045               (not (string-equal (downcase (Info-extract-pointer "up"))
1046                                  "top")))
1047          (let ((old-node Info-current-node))
1048            (Info-up)
1049            (let (Info-history success)
1050              (unwind-protect
1051                  (setq success (Info-forward-node t no-error))
1052                (or success (Info-goto-node old-node))))))
1053         (no-error nil)
1054         (t (error "No pointer forward from this node"))))
1055
1056 (defun Info-backward-node ()
1057   "Go backward one node, considering all nodes as forming one sequence."
1058   (interactive)
1059   (let ((prevnode (Info-extract-pointer "prev[ious]*" t))
1060         (upnode (Info-extract-pointer "up" t)))
1061     (cond ((and upnode (string-match "(" upnode))
1062            (error "First node in file"))
1063           ((and upnode (or (null prevnode)
1064                            ;; Use string-equal, not equal,
1065                            ;; to ignore text properties.
1066                            (string-equal (downcase prevnode)
1067                                          (downcase upnode))))
1068            (Info-up))
1069           (prevnode
1070            ;; If we move back at the same level,
1071            ;; go down to find the last subnode*.
1072            (Info-prev)
1073            (let (Info-history)
1074              (while (and (not (string-match "\\<index\\>" Info-current-node))
1075                          (save-excursion (search-forward "\n* Menu:" nil t)))
1076                (Info-goto-node (Info-extract-menu-counting nil)))))
1077           (t
1078            (error "No pointer backward from this node")))))
1079
1080 (defun Info-exit ()
1081   "Exit Info by selecting some other buffer."
1082   (interactive)
1083   (if Info-standalone
1084       (save-buffers-kill-emacs)
1085     (switch-to-buffer (prog1 (other-buffer (current-buffer))
1086                         (bury-buffer (current-buffer))))))
1087
1088 (defun Info-next-menu-item ()
1089   (interactive)
1090   (save-excursion
1091     (forward-line -1)
1092     (search-forward "\n* menu:" nil t)
1093     (or (search-forward "\n* " nil t)
1094         (error "No more items in menu"))
1095     (Info-goto-node (Info-extract-menu-node-name))))
1096
1097 (defun Info-last-menu-item ()
1098   (interactive)
1099   (save-excursion
1100     (forward-line 1)
1101     (let ((beg (save-excursion
1102                  (and (search-backward "\n* menu:" nil t)
1103                       (point)))))
1104       (or (and beg (search-backward "\n* " beg t))
1105           (error "No previous items in menu")))
1106     (Info-goto-node (save-excursion
1107                       (goto-char (match-end 0))
1108                       (Info-extract-menu-node-name)))))
1109
1110 (defmacro Info-no-error (&rest body)
1111   (list 'condition-case nil (cons 'progn (append body '(t))) '(error nil)))
1112
1113 (defun Info-next-preorder ()
1114   "Go to the next subnode or the next node, or go up a level."
1115   (interactive)
1116   (cond ((Info-no-error (Info-next-menu-item)))
1117         ((Info-no-error (Info-next)))
1118         ((Info-no-error (Info-up))
1119          ;; Since we have already gone thru all the items in this menu,
1120          ;; go up to the end of this node.
1121          (goto-char (point-max)))
1122         (t
1123          (error "No more nodes"))))
1124
1125 (defun Info-last-preorder ()
1126   "Go to the last node, popping up a level if there is none."
1127   (interactive)
1128   (cond ((Info-no-error
1129           (Info-last-menu-item)
1130           ;; If we go down a menu item, go to the end of the node
1131           ;; so we can scroll back through it.
1132           (goto-char (point-max)))
1133          (recenter -1))
1134         ((Info-no-error (Info-prev))
1135          (goto-char (point-max))
1136          (recenter -1))
1137         ((Info-no-error (Info-up))
1138          (goto-char (point-min))
1139          (or (search-forward "\n* Menu:" nil t)
1140              (goto-char (point-max))))
1141         (t (error "No previous nodes"))))
1142
1143 (defun Info-scroll-up ()
1144   "Scroll one screenful forward in Info, considering all nodes as one sequence.
1145 Once you scroll far enough in a node that its menu appears on the screen,
1146 the next scroll moves into its first subnode.  When you scroll past
1147 the end of a node, that goes to the next node or back up to the parent node."
1148   (interactive)
1149   (if (or (< (window-start) (point-min))
1150           (> (window-start) (point-max)))
1151       (set-window-start (selected-window) (point)))
1152   (let ((virtual-end (save-excursion
1153                        (goto-char (point-min))
1154                        (if (search-forward "\n* Menu:" nil t)
1155                            (point)
1156                          (point-max)))))
1157     (if (or (< virtual-end (window-start))
1158             (pos-visible-in-window-p virtual-end))
1159         (Info-next-preorder)
1160       (scroll-up))))
1161
1162 (defun Info-scroll-down ()
1163   "Scroll one screenful back in Info, considering all nodes as one sequence.
1164 Within the menu of a node, this goes to its last subnode.
1165 When you scroll past the beginning of a node, that goes to the
1166 previous node or back up to the parent node."
1167   (interactive)
1168   (if (or (< (window-start) (point-min))
1169           (> (window-start) (point-max)))
1170       (set-window-start (selected-window) (point)))
1171   (let ((virtual-end (save-excursion
1172                        (goto-char (point-min))
1173                        (search-forward "\n* Menu:" nil t))))
1174     (if (or virtual-end (pos-visible-in-window-p (point-min)))
1175         (Info-last-preorder)
1176       (scroll-down))))
1177
1178 (defun Info-next-reference ()
1179   "Move cursor to the next cross-reference or menu item in the node."
1180   (interactive)
1181   (let ((pat "\\*note[ \n\t]*\\([^:]*\\):\\|^\\* .*:")
1182         (old-pt (point)))
1183     (or (eobp) (forward-char 1))
1184     (or (re-search-forward pat nil t)
1185         (progn
1186           (goto-char (point-min))
1187           (or (re-search-forward pat nil t)
1188               (progn
1189                 (goto-char old-pt)
1190                 (error "No cross references in this node")))))
1191     (goto-char (match-beginning 0))
1192     (if (looking-at "\\* Menu:")
1193         (Info-next-reference))))
1194
1195 (defun Info-prev-reference ()
1196   "Move cursor to the previous cross-reference or menu item in the node."
1197   (interactive)
1198   (let ((pat "\\*note[ \n\t]*\\([^:]*\\):\\|^\\* .*:")
1199         (old-pt (point)))
1200     (or (re-search-backward pat nil t)
1201         (progn
1202           (goto-char (point-max))
1203           (or (re-search-backward pat nil t)
1204               (progn
1205                 (goto-char old-pt)
1206                 (error "No cross references in this node")))))
1207     (goto-char (match-beginning 0))
1208     (if (looking-at "\\* Menu:")
1209         (Info-prev-reference))))
1210
1211 (defun Info-index (topic)
1212   "Look up a string in the index for this file.
1213 The index is defined as the first node in the top-level menu whose
1214 name contains the word \"Index\", plus any immediately following
1215 nodes whose names also contain the word \"Index\".
1216 If there are no exact matches to the specified topic, this chooses
1217 the first match which is a case-insensitive substring of a topic.
1218 Use the `,' command to see the other matches.
1219 Give a blank topic name to go to the Index node itself."
1220   (interactive "sIndex topic: ")
1221   (let ((orignode Info-current-node)
1222         (rnode nil)
1223         (pattern (format "\n\\* \\([^\n:]*%s[^\n:]*\\):[ \t]*\\([^.\n]*\\)\\.[ \t]*\\([0-9]*\\)"
1224                          (regexp-quote topic)))
1225         node)
1226     (Info-goto-node "Top")
1227     (or (search-forward "\n* menu:" nil t)
1228         (error "No index"))
1229     (or (re-search-forward "\n\\* \\(.*\\<Index\\>\\)" nil t)
1230         (error "No index"))
1231     (goto-char (match-beginning 1))
1232     ;; Here, and subsequently in this function,
1233     ;; we bind Info-history to nil for internal node-switches
1234     ;; so that we don't put junk in the history.
1235     ;; In the first Info-goto-node call, above, we do update the history
1236     ;; because that is what the user's previous node choice into it.
1237     (let ((Info-history nil))
1238       (Info-goto-node (Info-extract-menu-node-name)))
1239     (or (equal topic "")
1240         (let ((matches nil)
1241               (exact nil)
1242               (Info-history nil)
1243               found)
1244           (while
1245               (progn
1246                 (goto-char (point-min))
1247                 (while (re-search-forward pattern nil t)
1248                   (setq matches
1249                         (cons (list (buffer-substring (match-beginning 1)
1250                                                       (match-end 1))
1251                                     (buffer-substring (match-beginning 2)
1252                                                       (match-end 2))
1253                                     Info-current-node
1254                                     (string-to-int (concat "0"
1255                                                            (buffer-substring
1256                                                             (match-beginning 3)
1257                                                             (match-end 3)))))
1258                               matches)))
1259                 (and (setq node (Info-extract-pointer "next" t))
1260                      (string-match "\\<Index\\>" node)))
1261             (Info-goto-node node))
1262           (or matches
1263               (progn
1264                 (Info-last)
1265                 (error "No \"%s\" in index" topic)))
1266           ;; Here it is a feature that assoc is case-sensitive.
1267           (while (setq found (assoc topic matches))
1268             (setq exact (cons found exact)
1269                   matches (delq found matches)))
1270           (setq Info-index-alternatives (nconc exact (nreverse matches)))
1271           (Info-index-next 0)))))
1272
1273 (defun Info-index-next (num)
1274   "Go to the next matching index item from the last `i' command."
1275   (interactive "p")
1276   (or Info-index-alternatives
1277       (error "No previous `i' command in this file"))
1278   (while (< num 0)
1279     (setq num (+ num (length Info-index-alternatives))))
1280   (while (> num 0)
1281     (setq Info-index-alternatives
1282           (nconc (cdr Info-index-alternatives)
1283                  (list (car Info-index-alternatives)))
1284           num (1- num)))
1285   (Info-goto-node (nth 1 (car Info-index-alternatives)))
1286   (if (> (nth 3 (car Info-index-alternatives)) 0)
1287       (forward-line (nth 3 (car Info-index-alternatives)))
1288     (forward-line 3)  ; don't search in headers
1289     (let ((name (car (car Info-index-alternatives))))
1290       (if (or (re-search-forward (format
1291                                   "\\(Function\\|Command\\): %s\\( \\|$\\)"
1292                                   (regexp-quote name)) nil t)
1293               (search-forward (format "`%s'" name) nil t)
1294               (and (string-match "\\`.*\\( (.*)\\)\\'" name)
1295                    (search-forward
1296                     (format "`%s'" (substring name 0 (match-beginning 1)))
1297                     nil t))
1298               (search-forward name nil t))
1299           (beginning-of-line)
1300         (goto-char (point-min)))))
1301   (message "Found \"%s\" in %s.  %s"
1302            (car (car Info-index-alternatives))
1303            (nth 2 (car Info-index-alternatives))
1304            (if (cdr Info-index-alternatives)
1305                "(Press `,' for more)"
1306              "(Only match)")))
1307
1308 (defun Info-undefined ()
1309   "Make command be undefined in Info."
1310   (interactive)
1311   (ding))
1312
1313 (defun Info-help ()
1314   "Enter the Info tutorial."
1315   (interactive)
1316   (delete-other-windows)
1317   (Info-find-node "info"
1318                   (if (< (window-height) 23)
1319                       "Help-Small-Screen"
1320                     "Help")))
1321
1322 (defun Info-summary ()
1323   "Display a brief summary of all Info commands."
1324   (interactive)
1325   (save-window-excursion
1326     (switch-to-buffer "*Help*")
1327     (erase-buffer)
1328     (insert (documentation 'Info-mode))
1329     (help-mode)
1330     (goto-char (point-min))
1331     (let (ch flag)
1332       (while (progn (setq flag (not (pos-visible-in-window-p (point-max))))
1333                     (message (if flag "Type Space to see more"
1334                                "Type Space to return to Info"))
1335                     (if (not (eq ?\  (setq ch (read-event))))
1336                         (progn (setq unread-command-events (list ch)) nil)
1337                       flag))
1338         (scroll-up)))
1339     (bury-buffer "*Help*")))
1340 \f
1341 (defun Info-get-token (pos start all &optional errorstring)
1342   "Return the token around POS,
1343 POS must be somewhere inside the token
1344 START is a regular expression which will match the
1345     beginning of the tokens delimited string
1346 ALL is a regular expression with a single
1347     parenthized subpattern which is the token to be
1348     returned. E.g. '{\(.*\)}' would return any string
1349     enclosed in braces around POS.
1350 SIG optional fourth argument, controls action on no match
1351     nil: return nil
1352     t: beep
1353     a string: signal an error, using that string."
1354   (save-excursion
1355     (goto-char pos)
1356     (re-search-backward start (max (point-min) (- pos 200)) 'yes)
1357     (let (found)
1358       (while (and (re-search-forward all (min (point-max) (+ pos 200)) 'yes)
1359                   (not (setq found (and (<= (match-beginning 0) pos)
1360                                         (> (match-end 0) pos))))))
1361       (if (and found (<= (match-beginning 0) pos)
1362                (> (match-end 0) pos))
1363           (buffer-substring (match-beginning 1) (match-end 1))
1364         (cond ((null errorstring)
1365                nil)
1366               ((eq errorstring t)
1367                (beep)
1368                nil)
1369               (t
1370                (error "No %s around position %d" errorstring pos)))))))
1371
1372 (defun Info-mouse-follow-nearest-node (click)
1373   "\\<Info-mode-map>Follow a node reference near point.
1374 Like \\[Info-menu], \\[Info-follow-reference], \\[Info-next], \\[Info-prev] or \\[Info-up] command, depending on where you click.
1375 At end of the node's text, moves to the next node, or up if none."
1376   (interactive "e")
1377   (let* ((start (event-start click))
1378          (window (car start))
1379          (pos (car (cdr start))))
1380     (select-window window)
1381     (goto-char pos))
1382   (and (not (Info-try-follow-nearest-node))
1383        (save-excursion (forward-line 1) (eobp))
1384        (Info-next-preorder)))
1385
1386 (defun Info-follow-nearest-node ()
1387   "\\<Info-mode-map>Follow a node reference near point.
1388 Like \\[Info-menu], \\[Info-follow-reference], \\[Info-next], \\[Info-prev] or \\[Info-up] command, depending on where point is.
1389 If no reference to follow, moves to the next node, or up if none."
1390   (interactive)
1391   (or (Info-try-follow-nearest-node)
1392       (Info-next-preorder)))
1393
1394 ;; Common subroutine.
1395 (defun Info-try-follow-nearest-node ()
1396   "Follow a node reference near point.  Return non-nil if successful."
1397   (let (node)
1398     (cond
1399      ((setq node (Info-get-token (point) "\\*note[ \n]"
1400                                  "\\*note[ \n]\\([^:]*\\):"))
1401       (Info-follow-reference node))
1402      ((setq node (Info-get-token (point) "\\* " "\\* \\([^:]*\\)::"))
1403       (Info-goto-node node))
1404      ((setq node (Info-get-token (point) "\\* " "\\* \\([^:]*\\):"))
1405       (Info-menu node))
1406      ((setq node (Info-get-token (point) "Up: " "Up: \\([^,\n\t]*\\)"))
1407       (Info-goto-node node))
1408      ((setq node (Info-get-token (point) "Next: " "Next: \\([^,\n\t]*\\)"))
1409       (Info-goto-node node))
1410      ((setq node (Info-get-token (point) "File: " "File: \\([^,\n\t]*\\)"))
1411       (Info-goto-node "Top"))
1412      ((setq node (Info-get-token (point) "Prev: " "Prev: \\([^,\n\t]*\\)"))
1413       (Info-goto-node node)))
1414     node))
1415 \f
1416 (defvar Info-mode-map nil
1417   "Keymap containing Info commands.")
1418 (if Info-mode-map
1419     nil
1420   (setq Info-mode-map (make-keymap))
1421   (suppress-keymap Info-mode-map)
1422   (define-key Info-mode-map "." 'beginning-of-buffer)
1423   (define-key Info-mode-map " " 'Info-scroll-up)
1424   (define-key Info-mode-map "\C-m" 'Info-follow-nearest-node)
1425   (define-key Info-mode-map "\t" 'Info-next-reference)
1426   (define-key Info-mode-map "\e\t" 'Info-prev-reference)
1427   (define-key Info-mode-map "1" 'Info-nth-menu-item)
1428   (define-key Info-mode-map "2" 'Info-nth-menu-item)
1429   (define-key Info-mode-map "3" 'Info-nth-menu-item)
1430   (define-key Info-mode-map "4" 'Info-nth-menu-item)
1431   (define-key Info-mode-map "5" 'Info-nth-menu-item)
1432   (define-key Info-mode-map "6" 'Info-nth-menu-item)
1433   (define-key Info-mode-map "7" 'Info-nth-menu-item)
1434   (define-key Info-mode-map "8" 'Info-nth-menu-item)
1435   (define-key Info-mode-map "9" 'Info-nth-menu-item)
1436   (define-key Info-mode-map "0" 'undefined)
1437   (define-key Info-mode-map "?" 'Info-summary)
1438   (define-key Info-mode-map "]" 'Info-forward-node)
1439   (define-key Info-mode-map "[" 'Info-backward-node)
1440   (define-key Info-mode-map "<" 'Info-top-node)
1441   (define-key Info-mode-map ">" 'Info-final-node)
1442   (define-key Info-mode-map "b" 'beginning-of-buffer)
1443   (define-key Info-mode-map "d" 'Info-directory)
1444   (define-key Info-mode-map "e" 'Info-edit)
1445   (define-key Info-mode-map "f" 'Info-follow-reference)
1446   (define-key Info-mode-map "g" 'Info-goto-node)
1447   (define-key Info-mode-map "h" 'Info-help)
1448   (define-key Info-mode-map "i" 'Info-index)
1449   (define-key Info-mode-map "l" 'Info-last)
1450   (define-key Info-mode-map "m" 'Info-menu)
1451   (define-key Info-mode-map "n" 'Info-next)
1452   (define-key Info-mode-map "p" 'Info-prev)
1453   (define-key Info-mode-map "q" 'Info-exit)
1454   (define-key Info-mode-map "s" 'Info-search)
1455   ;; For consistency with Rmail.
1456   (define-key Info-mode-map "\M-s" 'Info-search)
1457   (define-key Info-mode-map "t" 'Info-top-node)
1458   (define-key Info-mode-map "u" 'Info-up)
1459   (define-key Info-mode-map "," 'Info-index-next)
1460   (define-key Info-mode-map "\177" 'Info-scroll-down)
1461   (define-key Info-mode-map [mouse-2] 'Info-mouse-follow-nearest-node)
1462   )
1463 \f
1464 ;; Info mode is suitable only for specially formatted data.
1465 (put 'info-mode 'mode-class 'special)
1466
1467 (defun Info-mode ()
1468   "\\<Info-mode-map>
1469 Info mode provides commands for browsing through the Info documentation tree.
1470 Documentation in Info is divided into \"nodes\", each of which discusses
1471 one topic and contains references to other nodes which discuss related
1472 topics.  Info has commands to follow the references and show you other nodes.
1473
1474 \\[Info-help]   Invoke the Info tutorial.
1475
1476 Selecting other nodes:
1477 \\[Info-mouse-follow-nearest-node]
1478         Follow a node reference you click on.
1479           This works with menu items, cross references, and
1480           the \"next\", \"previous\" and \"up\", depending on where you click.
1481 \\[Info-next]   Move to the \"next\" node of this node.
1482 \\[Info-prev]   Move to the \"previous\" node of this node.
1483 \\[Info-up]     Move \"up\" from this node.
1484 \\[Info-menu]   Pick menu item specified by name (or abbreviation).
1485         Picking a menu item causes another node to be selected.
1486 \\[Info-directory]      Go to the Info directory node.
1487 \\[Info-follow-reference]       Follow a cross reference.  Reads name of reference.
1488 \\[Info-last]   Move to the last node you were at.
1489 \\[Info-index]  Look up a topic in this file's Index and move to that node.
1490 \\[Info-index-next]     (comma) Move to the next match from a previous `i' command.
1491
1492 Moving within a node:
1493 \\[Info-scroll-up]      Normally, scroll forward a full screen.  If the end of the buffer is
1494 already visible, try to go to the next menu entry, or up if there is none.
1495 \\[Info-scroll-down]  Normally, scroll backward.  If the beginning of the buffer is
1496 already visible, try to go to the previous menu entry, or up if there is none.
1497 \\[beginning-of-buffer] Go to beginning of node.
1498
1499 Advanced commands:
1500 \\[Info-exit]   Quit Info: reselect previously selected buffer.
1501 \\[Info-edit]   Edit contents of selected node.
1502 1       Pick first item in node's menu.
1503 2, 3, 4, 5   Pick second ... fifth item in node's menu.
1504 \\[Info-goto-node]      Move to node specified by name.
1505         You may include a filename as well, as (FILENAME)NODENAME.
1506 \\[universal-argument] \\[info] Move to new Info file with completion.
1507 \\[Info-search] Search through this Info file for specified regexp,
1508         and select the node in which the next occurrence is found.
1509 \\[Info-next-reference] Move cursor to next cross-reference or menu item.
1510 \\[Info-prev-reference] Move cursor to previous cross-reference or menu item."
1511   (kill-all-local-variables)
1512   (setq major-mode 'Info-mode)
1513   (setq mode-name "Info")
1514   (use-local-map Info-mode-map)
1515   (set-syntax-table text-mode-syntax-table)
1516   (setq local-abbrev-table text-mode-abbrev-table)
1517   (setq case-fold-search t)
1518   (setq buffer-read-only t)
1519   (make-local-variable 'Info-current-file)
1520   (make-local-variable 'Info-current-subfile)
1521   (make-local-variable 'Info-current-node)
1522   (make-local-variable 'Info-tag-table-marker)
1523   (make-local-variable 'Info-history)
1524   (make-local-variable 'Info-index-alternatives)
1525   (if (memq (framep (selected-frame)) '(x pc))
1526       (progn
1527         (make-face 'info-node)
1528         (make-face 'info-menu-5)
1529         (make-face 'info-xref)
1530         (or (face-differs-from-default-p 'info-node)
1531             (if (face-differs-from-default-p 'bold-italic)
1532                 (copy-face 'bold-italic 'info-node)
1533               (copy-face 'bold 'info-node)))
1534         (or (face-differs-from-default-p 'info-menu-5)
1535             (set-face-underline-p 'info-menu-5 t))
1536         (or (face-differs-from-default-p 'info-xref)
1537             (copy-face 'bold 'info-xref)))
1538     (setq Info-fontify nil))
1539   (Info-set-mode-line)
1540   (run-hooks 'Info-mode-hook))
1541
1542 (defvar Info-edit-map nil
1543   "Local keymap used within `e' command of Info.")
1544 (if Info-edit-map
1545     nil
1546   (setq Info-edit-map (nconc (make-sparse-keymap) text-mode-map))
1547   (define-key Info-edit-map "\C-c\C-c" 'Info-cease-edit))
1548
1549 ;; Info-edit mode is suitable only for specially formatted data.
1550 (put 'info-edit-mode 'mode-class 'special)
1551
1552 (defun Info-edit-mode ()
1553   "Major mode for editing the contents of an Info node.
1554 Like text mode with the addition of `Info-cease-edit'
1555 which returns to Info mode for browsing.
1556 \\{Info-edit-map}"
1557   (use-local-map Info-edit-map)
1558   (setq major-mode 'Info-edit-mode)
1559   (setq mode-name "Info Edit")
1560   (kill-local-variable 'mode-line-buffer-identification)
1561   (setq buffer-read-only nil)
1562   (force-mode-line-update)
1563   (buffer-enable-undo (current-buffer))
1564   (run-hooks 'Info-edit-mode-hook))
1565
1566 (defun Info-edit ()
1567   "Edit the contents of this Info node.
1568 Allowed only if variable `Info-enable-edit' is non-nil."
1569   (interactive)
1570   (or Info-enable-edit
1571       (error "Editing info nodes is not enabled"))
1572   (Info-edit-mode)
1573   (message (substitute-command-keys
1574             "Editing: Type \\<Info-edit-map>\\[Info-cease-edit] to return to info")))
1575
1576 (defun Info-cease-edit ()
1577   "Finish editing Info node; switch back to Info proper."
1578   (interactive)
1579   ;; Do this first, so nothing has changed if user C-g's at query.
1580   (and (buffer-modified-p)
1581        (y-or-n-p "Save the file? ")
1582        (save-buffer))
1583   (use-local-map Info-mode-map)
1584   (setq major-mode 'Info-mode)
1585   (setq mode-name "Info")
1586   (Info-set-mode-line)
1587   (setq buffer-read-only t)
1588   (force-mode-line-update)
1589   (and (marker-position Info-tag-table-marker)
1590        (buffer-modified-p)
1591        (message "Tags may have changed.  Use Info-tagify if necessary")))
1592 \f
1593 (defun Info-find-emacs-command-nodes (command)
1594   "Return a list of locations documenting COMMAND in the Emacs Info manual.
1595 The locations are of the format used in Info-history, i.e.
1596 \(FILENAME NODENAME BUFFERPOS\)."
1597   (require 'info)
1598   (let ((where '())
1599         (cmd-desc (concat "^\\* " (regexp-quote (symbol-name command))
1600                           ":\\s *\\(.*\\)\\.$")))
1601     (save-excursion
1602       (Info-find-node "emacs" "Command Index")
1603       ;; Take the index node off the Info history.
1604       (setq Info-history (cdr Info-history))
1605       (goto-char (point-max))
1606       (while (re-search-backward cmd-desc nil t)
1607           (setq where (cons (list Info-current-file
1608                                   (buffer-substring
1609                                    (match-beginning 1)
1610                                    (match-end 1))
1611                                   0)
1612                             where)))
1613       where)))
1614
1615 ;;;###autoload
1616 (defun Info-goto-emacs-command-node (command)
1617   "Go to the Info node in the Emacs manual for command COMMAND.
1618 The command is found by looking up in Emacs manual's Command Index."
1619   (interactive "CFind documentation for command: ")
1620   (or (commandp command)
1621       (signal 'wrong-type-argument (list 'commandp command)))
1622   (let ((where (Info-find-emacs-command-nodes command)))
1623     (if where
1624         (let ((num-matches (length where)))
1625           ;; Get Info running, and pop to it in another window.
1626           (save-window-excursion
1627             (info))
1628           (pop-to-buffer "*info*")
1629           (Info-find-node (car (car where))
1630                           (car (cdr (car where))))
1631           (if (> num-matches 1)
1632               (progn
1633                 ;; Info-find-node already pushed (car where) onto
1634                 ;; Info-history.  Put the other nodes that were found on
1635                 ;; the history.
1636                 (setq Info-history (nconc (cdr where) Info-history))
1637                 (message (substitute-command-keys
1638                           "Found %d other entr%s.  Use \\[Info-last] to see %s.")
1639                          (1- num-matches)
1640                          (if (> num-matches 2) "ies" "y")
1641                          (if (> num-matches 2) "them" "it")))))
1642       (error "Couldn't find documentation for %s." command))))
1643
1644 ;;;###autoload
1645 (defun Info-goto-emacs-key-command-node (key)
1646   "Go to the Info node in the Emacs manual the command bound to KEY, a string.
1647 Interactively, if the binding is execute-extended-command, a command is read.
1648 The command is found by looking up in Emacs manual's Command Index."
1649   (interactive "kFind documentation for key:")
1650   (let ((command (key-binding key)))
1651     (cond ((null command)
1652            (message "%s is undefined" (key-description key)))
1653           ((and (interactive-p)
1654                 (eq command 'execute-extended-command))
1655            (Info-goto-emacs-command-node
1656             (read-command "Find documentation for command: ")))
1657           (t
1658            (Info-goto-emacs-command-node command)))))
1659 \f
1660 (defun Info-fontify-node ()
1661   (save-excursion
1662     (let ((buffer-read-only nil))
1663       (goto-char (point-min))
1664       (if (looking-at "^File: [^,: \t]+,?[ \t]+")
1665           (progn
1666             (goto-char (match-end 0))
1667             (while
1668                 (looking-at "[ \t]*[^:, \t\n]+:[ \t]+\\([^:,\t\n]+\\),?")
1669               (goto-char (match-end 0))
1670               (put-text-property (match-beginning 1) (match-end 1)
1671                                  'face 'info-xref)
1672               (put-text-property (match-beginning 1) (match-end 1)
1673                                  'mouse-face 'highlight))))
1674       (goto-char (point-min))
1675       (while (re-search-forward "\\*Note[ \n\t]+\\([^:]*\\):" nil t)
1676         (if (= (char-after (1- (match-beginning 0))) ?\") ; hack
1677             nil
1678           (put-text-property (match-beginning 1) (match-end 1)
1679                              'face 'info-xref)
1680           (put-text-property (match-beginning 1) (match-end 1)
1681                              'mouse-face 'highlight)))
1682       (goto-char (point-min))
1683       (if (and (search-forward "\n* Menu:" nil t)
1684                (not (string-match "\\<Index\\>" Info-current-node))
1685                ;; Don't take time to annotate huge menus
1686                (< (- (point-max) (point)) Info-fontify-maximum-menu-size))
1687           (let ((n 0))
1688             (while (re-search-forward "^\\* \\([^:\t\n]*\\):" nil t)
1689               (setq n (1+ n))
1690               (if (memq n '(5 9))   ; visual aids to help with 1-9 keys
1691                   (put-text-property (match-beginning 0)
1692                                      (1+ (match-beginning 0))
1693                                      'face 'info-menu-5))
1694               (put-text-property (match-beginning 1) (match-end 1)
1695                                  'face 'info-node)
1696               (put-text-property (match-beginning 1) (match-end 1)
1697                                  'mouse-face 'highlight))))
1698       (set-buffer-modified-p nil))))
1699
1700 (provide 'info)
1701
1702 ;;; info.el ends here