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;;; info.el --- info package for Emacs.
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;; Copyright (C) 1985, 86, 92, 93, 94, 95, 96, 97, 98, 99, 2000 Free Software
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;; Foundation, Inc.
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;; Maintainer: FSF
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;; Keywords: help
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;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2, or (at your option)
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;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
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;;; Commentary:

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;; Note that nowadays we expect info files to be made using makeinfo.
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;;; Code:

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(eval-when-compile (require 'jka-compr))

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(defgroup info nil
  "Info subsystem"
  :group 'help
  :group 'docs)


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(defvar Info-history nil
  "List of info nodes user has visited.
Each element of list is a list (FILENAME NODENAME BUFFERPOS).")

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(defcustom Info-enable-edit nil
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  "*Non-nil means the \\<Info-mode-map>\\[Info-edit] command in Info can edit the current node.
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This is convenient if you want to write info files by hand.
However, we recommend that you not do this.
It is better to write a Texinfo file and generate the Info file from that,
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because that gives you a printed manual as well."
  :type 'boolean
  :group 'info)
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(defvar Info-enable-active-nodes nil
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  "Non-nil allows Info to execute Lisp code associated with nodes.
The Lisp code is executed when the node is selected.")
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(put 'Info-enable-active-nodes 'risky-local-variable t)
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(defcustom Info-fontify t
  "*Non-nil enables highlighting and fonts in Info nodes."
  :type 'boolean
  :group 'info)
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(defface info-node
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  '((((class color)) (:foreground "brown" :bold t :italic t))
    (t (:bold t :italic t)))
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  "Face for Info node names."
  :group 'info)

(defface info-menu-5
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  '((((class color)) (:foreground "red1"))
    (t (:underline t)))
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  "Face for the fifth and tenth `*' in an Info menu."
  :group 'info)

(defface info-xref
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  '((((class color)) (:foreground "magenta4" :bold t))
    (t (:bold t)))
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  "Face for Info cross-references."
  :group 'info)

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(defcustom Info-fontify-maximum-menu-size 100000
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  "*Maximum size of menu to fontify if `Info-fontify' is non-nil."
  :type 'integer
  :group 'info)
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(defvar Info-directory-list nil
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  "List of directories to search for Info documentation files.
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nil means not yet initialized.  In this case, Info uses the environment
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variable INFOPATH to initialize it, or `Info-default-directory-list'
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if there is no INFOPATH variable in the environment.
The last element of `Info-default-directory-list' is the directory
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where Emacs installs the Info files that come with it.
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If you run the Emacs executable from the `src' directory in the Emacs
source tree, the `info' directory in the source tree is used as the last
element, in place of the installation Info directory.  This is useful
when you run a version of Emacs without installing it.")
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(defcustom Info-additional-directory-list nil
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  "List of additional directories to search for Info documentation files.
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These directories are not searched for merging the `dir' file."
  :type '(repeat directory)
  :group 'info)
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(defvar Info-current-file nil
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  "Info file that Info is now looking at, or nil.
This is the name that was specified in Info, not the actual file name.
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It doesn't contain directory names or file name extensions added by Info.
Can also be t when using `Info-on-current-buffer'.")
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(defvar Info-current-subfile nil
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  "Info subfile that is actually in the *info* buffer now.
nil if current info file is not split into subfiles.")
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(defvar Info-current-node nil
  "Name of node that Info is now looking at, or nil.")

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(defvar Info-tag-table-marker nil
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  "Marker pointing at beginning of current Info file's tag table.
Marker points nowhere if file has no tag table.")

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(defvar Info-tag-table-buffer nil
  "Buffer used for indirect tag tables.")

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(defvar Info-current-file-completions nil
  "Cached completion list for current Info file.")

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(defvar Info-index-alternatives nil
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  "List of possible matches for last `Info-index' command.")
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(defvar Info-standalone nil
  "Non-nil if Emacs was started solely as an Info browser.")
133

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(defvar Info-suffix-list
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  ;; The MS-DOS list should work both when long file names are
  ;; supported (Windows 9X), and when only 8+3 file names are available.
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  (if (eq system-type 'ms-dos)
      '( (".gz"      . "gunzip")
	 (".z"       . "gunzip")
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	 (".bz2"     . "bzip2 -dc")
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	 (".inz"     . "gunzip")
	 (".igz"     . "gunzip")
	 (".info.Z"  . "gunzip")
	 (".info.gz" . "gunzip")
	 ("-info.Z"  . "gunzip")
	 ("-info.gz" . "gunzip")
	 ("/index.gz". "gunzip")
	 ("/index.z" . "gunzip")
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	 (".inf"     . nil)
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	 (".info"    . nil)
	 ("-info"    . nil)
	 ("/index"   . nil)
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	 (""         . nil))
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    '( (".info.Z".    "uncompress")
       (".info.Y".    "unyabba")
       (".info.gz".   "gunzip")
       (".info.z".    "gunzip")
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       (".info.bz2" . "bzip2 -dc")
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       (".info".      nil)
       ("-info.Z".   "uncompress")
       ("-info.Y".   "unyabba")
       ("-info.gz".  "gunzip")
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       ("-info.bz2" . "bzip2 -dc")
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       ("-info.z".   "gunzip")
       ("-info".     nil)
       ("/index.Z".   "uncompress")
       ("/index.Y".   "unyabba")
       ("/index.gz".  "gunzip")
       ("/index.z".   "gunzip")
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       ("/index.bz2". "bzip2 -dc")
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       ("/index".     nil)
       (".Z".         "uncompress")
       (".Y".         "unyabba")
       (".gz".        "gunzip")
       (".z".         "gunzip")
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       (".bz2" .      "bzip2 -dc")
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       ("".           nil)))
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  "List of file name suffixes and associated decoding commands.
Each entry should be (SUFFIX . STRING); the file is given to
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the command as standard input.  If STRING is nil, no decoding is done.
Because the SUFFIXes are tried in order, the empty string should
be last in the list.")
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;; Concatenate SUFFIX onto FILENAME.  SUFFIX should start with a dot.
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;; First, on ms-dos, delete some of the extension in FILENAME
;; to make room.
(defun info-insert-file-contents-1 (filename suffix)
  (if (not (eq system-type 'ms-dos))
      (concat filename suffix)
    (let* ((sans-exts (file-name-sans-extension filename))
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	   ;; How long is the extension in FILENAME (not counting the dot).
	   (ext-len (max 0 (- (length filename) (length sans-exts) 1)))
	   ext-left)
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      ;; SUFFIX starts with a dot.  If FILENAME already has one,
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      ;; get rid of the one in SUFFIX (unless suffix is empty).
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      (or (and (<= ext-len 0)
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	       (not (eq (aref filename (1- (length filename))) ?.)))
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	  (= (length suffix) 0)
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	  (setq suffix (substring suffix 1)))
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      ;; How many chars of that extension should we keep?
      (setq ext-left (min ext-len (max 0 (- 3 (length suffix)))))
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      ;; Get rid of the rest of the extension, and add SUFFIX.
      (concat (substring filename 0 (- (length filename)
				       (- ext-len ext-left)))
	      suffix))))

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(defun info-file-exists-p (filename)
  (and (file-exists-p filename)
       (not (file-directory-p filename))))

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(defun info-insert-file-contents (filename &optional visit)
  "Insert the contents of an info file in the current buffer.
Do the right thing if the file has been compressed or zipped."
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  (let ((tail Info-suffix-list)
	fullname decoder)
    (if (file-exists-p filename)
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	;; FILENAME exists--see if that name contains a suffix.
	;; If so, set DECODE accordingly.
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	(progn
	  (while (and tail
		      (not (string-match
			    (concat (regexp-quote (car (car tail))) "$")
			    filename)))
	    (setq tail (cdr tail)))
	  (setq fullname filename
		decoder (cdr (car tail))))
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      ;; Try adding suffixes to FILENAME and see if we can find something.
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      (while (and tail
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		  (not (info-file-exists-p (info-insert-file-contents-1
					    filename (car (car tail))))))
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	(setq tail (cdr tail)))
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      ;; If we found a file with a suffix, set DECODER according to the suffix
      ;; and set FULLNAME to the file's actual name.
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      (setq fullname (info-insert-file-contents-1 filename (car (car tail)))
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	    decoder (cdr (car tail)))
      (or tail
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	  (error "Can't find %s or any compressed version of it" filename)))
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    ;; check for conflict with jka-compr
    (if (and (featurep 'jka-compr)
	     (jka-compr-installed-p)
	     (jka-compr-get-compression-info fullname))
	(setq decoder nil))
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    (if decoder
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	(progn
	  (insert-file-contents-literally fullname visit)
	  (let ((buffer-read-only nil)
		(coding-system-for-write 'no-conversion)
		(default-directory (or (file-name-directory fullname)
				       default-directory)))
	    (call-process-region (point-min) (point-max) decoder t t)))
      (insert-file-contents fullname visit))))
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(defun info-initialize ()
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  "Initialize `Info-directory-list', if that hasn't been done yet."
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  (unless Info-directory-list
    (let ((path (getenv "INFOPATH"))
	  (source (expand-file-name "info/" source-directory))
	  (sibling (if installation-directory
		       (expand-file-name "info/" installation-directory)))
	  alternative)
      (setq Info-directory-list
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	    (prune-directory-list
	     (if path
		 (split-string path (regexp-quote path-separator))
	       (if (and sibling (file-exists-p sibling))
		   ;; Uninstalled, Emacs builddir != srcdir.
		   (setq alternative sibling)
		 ;; Uninstalled, builddir == srcdir
		 (setq alternative source))
	       (if (or (member alternative Info-default-directory-list)
		       ;; On DOS/NT, we use movable executables always,
		       ;; and we must always find the Info dir at run time.
		       (if (memq system-type '(ms-dos windows-nt))
			   nil
			 ;; Use invocation-directory for Info
			 ;; only if we used it for exec-directory also.
			 (not (string= exec-directory
				       (expand-file-name "lib-src/"
							 installation-directory))))
		       (not (file-exists-p alternative)))
		   Info-default-directory-list
		 ;; `alternative' contains the Info files that came with this
		 ;; version, so we should look there first.  `Info-insert-dir'
		 ;; currently expects to find `alternative' first on the list.
		 (cons alternative
		       (reverse (cdr (reverse Info-default-directory-list)))))))))))
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;;;###autoload
(defun info-other-window (&optional file)
  "Like `info' but show the Info buffer in another window."
  (interactive (if current-prefix-arg
		   (list (read-file-name "Info file name: " nil nil t))))
  (let (same-window-buffer-names)
    (info file)))
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;;;###autoload (add-hook 'same-window-buffer-names "*info*")
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;;;###autoload
(defun info (&optional file)
  "Enter Info, the documentation browser.
Optional argument FILE specifies the file to examine;
the default is the top-level directory of Info.
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Called from a program, FILE may specify an Info node of the form
`(FILENAME)NODENAME'.
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In interactive use, a prefix argument directs this command
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to read a file name from the minibuffer.

The search path for Info files is in the variable `Info-directory-list'.
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The top-level Info directory is made by combining all the files named `dir'
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in all the directories in that path."
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  (interactive (if current-prefix-arg
		   (list (read-file-name "Info file name: " nil nil t))))
  (if file
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      (progn
	(pop-to-buffer "*info*")
	;; If argument already contains parentheses, don't add another set
	;; since the argument will then be parsed improperly.  This also
	;; has the added benefit of allowing node names to be included
	;; following the parenthesized filename.
	(if (and (stringp file) (string-match "(.*)" file))
	    (Info-goto-node file)
	  (Info-goto-node (concat "(" file ")"))))
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    (if (get-buffer "*info*")
	(pop-to-buffer "*info*")
      (Info-directory))))
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;;;###autoload
(defun info-standalone ()
  "Run Emacs as a standalone Info reader.
Usage:  emacs -f info-standalone [filename]
In standalone mode, \\<Info-mode-map>\\[Info-exit] exits Emacs itself."
  (setq Info-standalone t)
  (if (and command-line-args-left
	   (not (string-match "^-" (car command-line-args-left))))
      (condition-case err
	  (progn
	    (info (car command-line-args-left))
	    (setq command-line-args-left (cdr command-line-args-left)))
	(error (send-string-to-terminal
		(format "%s\n" (if (eq (car-safe err) 'error)
				   (nth 1 err) err)))
	       (save-buffers-kill-emacs)))
    (info)))
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;; See if the the accessible portion of the buffer begins with a node
;; delimiter, and the node header line which follows matches REGEXP.
;; Typically, this test will be followed by a loop that examines the
;; rest of the buffer with (search-forward "\n\^_"), and it's a pity
;; to have the overhead of this special test inside the loop.

;; This function changes match-data, but supposedly the caller might
;; want to use the results of re-search-backward.

;; The return value is the value of point at the beginning of matching
;; REGERXP, if the function succeeds, nil otherwise.
(defun Info-node-at-bob-matching (regexp)
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  (and (bobp)				; are we at beginning of buffer?
       (looking-at "\^_")		; does it begin with node delimiter?
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       (let (beg)
	 (forward-line 1)
	 (setq beg (point))
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	 (forward-line 1)		; does the line after delimiter match REGEXP?
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	 (re-search-backward regexp beg t))))

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(defun Info-find-node (filename nodename &optional no-going-back)
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  "Go to an info node specified as separate FILENAME and NODENAME.
NO-GOING-BACK is non-nil if recovering from an error in this function;
it says do not attempt further (recursive) error recovery."
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  (info-initialize)
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  ;; Convert filename to lower case if not found as specified.
  ;; Expand it.
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  (if (stringp filename)
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      (let (temp temp-downcase found)
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        (setq filename (substitute-in-file-name filename))
        (if (string= (downcase filename) "dir")
            (setq found t)
          (let ((dirs (if (string-match "^\\./" filename)
                          ;; If specified name starts with `./'
                          ;; then just try current directory.
                          '("./")
                        (if (file-name-absolute-p filename)
                            ;; No point in searching for an
                            ;; absolute file name
                            '(nil)
                          (if Info-additional-directory-list
                              (append Info-directory-list
                                      Info-additional-directory-list)
                            Info-directory-list)))))
            ;; Search the directory list for file FILENAME.
            (while (and dirs (not found))
              (setq temp (expand-file-name filename (car dirs)))
              (setq temp-downcase
                    (expand-file-name (downcase filename) (car dirs)))
              ;; Try several variants of specified name.
              (let ((suffix-list Info-suffix-list))
                (while (and suffix-list (not found))
                  (cond ((info-file-exists-p
                          (info-insert-file-contents-1
                           temp (car (car suffix-list))))
                         (setq found temp))
                        ((info-file-exists-p
                          (info-insert-file-contents-1
                           temp-downcase (car (car suffix-list))))
                         (setq found temp-downcase)))
                  (setq suffix-list (cdr suffix-list))))
              (setq dirs (cdr dirs)))))
        (if found
            (setq filename found)
          (error "Info file %s does not exist" filename))))
  ;; Record the node we are leaving.
  (if (and Info-current-file (not no-going-back))
      (setq Info-history
            (cons (list Info-current-file Info-current-node (point))
                  Info-history)))
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  ;; Go into info buffer.
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  (or (eq major-mode 'Info-mode) (pop-to-buffer "*info*"))
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  (Info-find-node-2 filename nodename no-going-back))

(defun Info-on-current-buffer (&optional nodename)
  "Use the `Info-mode' to browse the current info buffer.
If a prefix arg is provided, it queries for the NODENAME which
else defaults to `Top'."
  (interactive
   (list (if current-prefix-arg
	     (completing-read "Node name: " (Info-build-node-completions)
			      nil t "Top")
	   "Top")))
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  (info-initialize)
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  (Info-mode)
  (set (make-local-variable 'Info-current-file) t)
  (Info-find-node-2 nil nodename))

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(defun Info-find-in-tag-table-1 (marker regexp case-fold)
  "Find a node in a tag table.
MARKER specifies the buffer and position to start searching at.
REGEXP is a regular expression matching nodes or references.  Its first
group should match `Node:' or `Ref:'.
CASE-FOLD t means search for a case-insensitive match.
If a match was found, value is a list (FOUND-ANCHOR POS MODE), where
FOUND-ANCHOR is non-nil if a `Ref:' was matched, POS is the position
where the match was found, and MODE is `major-mode' of the buffer in
which the match was found."
  (let ((case-fold-search case-fold)
	found-mode guesspos found-anchor)
    (save-excursion
      (set-buffer (marker-buffer marker))
      (goto-char marker)
    
      ;; Search tag table
      (beginning-of-line)
      (when (re-search-forward regexp nil t)
	(list (string-equal "Ref:" (match-string 1))
	      (1+ (read (current-buffer)))
	      major-mode)))))

(defun Info-find-in-tag-table (marker regexp)
  "Find a node in a tag table.
MARKER specifies the buffer and position to start searching at.
REGEXP is a regular expression matching nodes or references.  Its first
group should match `Node:' or `Ref:'.
If a match was found, value is a list (FOUND-ANCHOR POS MODE), where
FOUND-ANCHOR is non-nil if a `Ref:' was matched, POS is the position
where the match was found, and MODE is `major-mode' of the buffer in
which the match was found.
This function tries to find a case-sensitive match first, then a
case-insensitive match is tried."
  (let ((result (Info-find-in-tag-table-1 marker regexp nil)))
    (when (null (car result))
      (setq result (Info-find-in-tag-table-1 marker regexp t)))
    result))

(defun Info-find-node-in-buffer-1 (regexp case-fold)
  "Find a node or anchor in the current buffer.
REGEXP is a regular expression matching nodes or references.  Its first
group should match `Node:' or `Ref:'.
CASE-FOLD t means search for a case-insensitive match.
Value is the position at which a match was found, or nil if not found."
  (let ((case-fold-search case-fold)
	found)
    (save-excursion
      (when (Info-node-at-bob-matching regexp)
	(setq found (point)))
      (while (and (not found)
		  (search-forward "\n\^_" nil t))
	(forward-line 1)
	(let ((beg (point)))
	  (forward-line 1)
	  (when (re-search-backward regexp beg t)
	    (beginning-of-line)
	    (setq found (point)))))
      found)))
		  
(defun Info-find-node-in-buffer (regexp)
  "Find a node or anchor in the current buffer.
REGEXP is a regular expression matching nodes or references.  Its first
group should match `Node:' or `Ref:'.
Value is the position at which a match was found, or nil if not found.
This function looks for a case-sensitive match first.  If none is found,
a case-insensitive match is tried."
  (or (Info-find-node-in-buffer-1 regexp nil)
      (Info-find-node-in-buffer-1 regexp t)))
  
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(defun Info-find-node-2 (filename nodename &optional no-going-back)
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  (buffer-disable-undo (current-buffer))
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  (or (eq major-mode 'Info-mode)
      (Info-mode))
  (widen)
  (setq Info-current-node nil)
  (unwind-protect
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      (let ((case-fold-search t)
	    anchorpos)
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        ;; Switch files if necessary
        (or (null filename)
            (equal Info-current-file filename)
            (let ((buffer-read-only nil))
              (setq Info-current-file nil
                    Info-current-subfile nil
                    Info-current-file-completions nil
                    buffer-file-name nil)
              (erase-buffer)
              (if (eq filename t)
                  (Info-insert-dir)
                (info-insert-file-contents filename t)
                (setq default-directory (file-name-directory filename)))
              (set-buffer-modified-p nil)
              ;; See whether file has a tag table.  Record the location if yes.
              (goto-char (point-max))
              (forward-line -8)
              ;; Use string-equal, not equal, to ignore text props.
              (if (not (or (string-equal nodename "*")
                           (not
                            (search-forward "\^_\nEnd tag table\n" nil t))))
                  (let (pos)
                    ;; We have a tag table.  Find its beginning.
                    ;; Is this an indirect file?
                    (search-backward "\nTag table:\n")
                    (setq pos (point))
                    (if (save-excursion
                          (forward-line 2)
                          (looking-at "(Indirect)\n"))
                        ;; It is indirect.  Copy it to another buffer
                        ;; and record that the tag table is in that buffer.
                        (let ((buf (current-buffer))
                              (tagbuf
                               (or Info-tag-table-buffer
                                   (generate-new-buffer " *info tag table*"))))
                          (setq Info-tag-table-buffer tagbuf)
                          (save-excursion
                            (set-buffer tagbuf)
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                            (buffer-disable-undo (current-buffer))
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                            (setq case-fold-search t)
                            (erase-buffer)
                            (insert-buffer-substring buf))
                          (set-marker Info-tag-table-marker
                                      (match-end 0) tagbuf))
                      (set-marker Info-tag-table-marker pos)))
                (set-marker Info-tag-table-marker nil))
              (setq Info-current-file
                    (if (eq filename t) "dir" filename))))
        ;; Use string-equal, not equal, to ignore text props.
        (if (string-equal nodename "*")
            (progn (setq Info-current-node nodename)
                   (Info-set-mode-line))
          ;; Possibilities:
          ;;
          ;; 1. Anchor found in tag table
          ;; 2. Anchor *not* in tag table
          ;;
          ;; 3. Node found in tag table
          ;; 4. Node *not* found in tag table, but found in file
          ;; 5. Node *not* in tag table, and *not* in file
          ;;
          ;; *Or* the same, but in an indirect subfile.

          ;; Search file for a suitable node.
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	  (let ((guesspos (point-min))
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		(regexp (concat "\\(Node:\\|Ref:\\) *\\("
				(regexp-quote nodename)
				"\\) *[,\t\n\177]"))
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		(nodepos nil))
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	    (catch 'foo
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	      ;; First, search a tag table, if any
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	      (when (marker-position Info-tag-table-marker)
		(let* ((m Info-tag-table-marker)
		       (found (Info-find-in-tag-table m regexp)))
		  
		  (when found
		    ;; FOUND is (ANCHOR POS MODE).
		    (setq guesspos (nth 1 found))
		    
		    ;; If this is an indirect file, determine which
		    ;; file really holds this node and read it in.
		    (unless (eq (nth 2 found) 'Info-mode)
		      ;; Note that the current buffer must be the
		      ;; *info* buffer on entry to
		      ;; Info-read-subfile.  Thus the hackery above.
		      (setq guesspos (Info-read-subfile guesspos)))
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		    ;; Handle anchor
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		    (when (nth 0 found)
		      (goto-char (setq anchorpos guesspos))
		      (throw 'foo t)))))
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	      ;; Else we may have a node, which we search for:
	      (goto-char (max (point-min)
			      (- (byte-to-position guesspos) 1000)))
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	      ;; Now search from our advised position (or from beg of
	      ;; buffer) to find the actual node.  First, check
	      ;; whether the node is right where we are, in case the
	      ;; buffer begins with a node.
	      (let ((pos (Info-find-node-in-buffer regexp)))
		(when pos
		  (goto-char pos)
		  (throw 'foo t))
		(error "No such anchor in tag table or node in tag table or file: %s"
		       nodename)))
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	    (Info-select-node)
	    (goto-char (or anchorpos (point-min))))))
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    ;; If we did not finish finding the specified node,
    ;; go back to the previous one.
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    (or Info-current-node no-going-back (null Info-history)
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        (let ((hist (car Info-history)))
          (setq Info-history (cdr Info-history))
          (Info-find-node (nth 0 hist) (nth 1 hist) t)
          (goto-char (nth 2 hist))))))
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;; Cache the contents of the (virtual) dir file, once we have merged
;; it for the first time, so we can save time subsequently.
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(defvar Info-dir-contents nil)

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;; Cache for the directory we decided to use for the default-directory
;; of the merged dir text.
(defvar Info-dir-contents-directory nil)

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;; Record the file attributes of all the files from which we
;; constructed Info-dir-contents.
(defvar Info-dir-file-attributes nil)

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(defvar Info-dir-file-name nil)

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;; Construct the Info directory node by merging the files named `dir'
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;; from various directories.  Set the *info* buffer's
;; default-directory to the first directory we actually get any text
;; from.
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(defun Info-insert-dir ()
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  (if (and Info-dir-contents Info-dir-file-attributes
	   ;; Verify that none of the files we used has changed
	   ;; since we used it.
	   (eval (cons 'and
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		       (mapcar (lambda (elt)
				 (let ((curr (file-attributes
					      ;; Handle symlinks
					      (file-truename (car elt)))))

				   ;; Don't compare the access time.
				   (if curr (setcar (nthcdr 4 curr) 0))
				   (setcar (nthcdr 4 (cdr elt)) 0)
				   (equal (cdr elt) curr)))
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			       Info-dir-file-attributes))))
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      (progn
	(insert Info-dir-contents)
	(goto-char (point-min)))
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    (let ((dirs Info-directory-list)
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	  ;; Bind this in case the user sets it to nil.
	  (case-fold-search t)
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	  ;; This is set non-nil if we find a problem in some input files.
	  problems
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	  buffers buffer others nodes dirs-done)
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      (setq Info-dir-file-attributes nil)

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      ;; Search the directory list for the directory file.
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      (while dirs
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	(let ((truename (file-truename (expand-file-name (car dirs)))))
	  (or (member truename dirs-done)
	      (member (directory-file-name truename) dirs-done)
	      ;; Try several variants of specified name.
	      ;; Try upcasing, appending `.info', or both.
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	      (let* (file
		     (attrs
		      (or
		       (progn (setq file (expand-file-name "dir" truename))
			      (file-attributes file))
		       (progn (setq file (expand-file-name "DIR" truename))
			      (file-attributes file))
		       (progn (setq file (expand-file-name "dir.info" truename))
			      (file-attributes file))
		       (progn (setq file (expand-file-name "DIR.INFO" truename))
			      (file-attributes file)))))
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		(setq dirs-done
		      (cons truename
			    (cons (directory-file-name truename)
				  dirs-done)))
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		(if attrs
		    (save-excursion
		      (or buffers
			  (message "Composing main Info directory..."))
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		      (set-buffer (generate-new-buffer " info dir"))
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		      (condition-case nil
			  (progn
			    (insert-file-contents file)
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			    (make-local-variable 'Info-dir-file-name)
			    (setq Info-dir-file-name file)
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			    (setq buffers (cons (current-buffer) buffers)
				  Info-dir-file-attributes
				  (cons (cons file attrs)
					Info-dir-file-attributes)))
			(error (kill-buffer (current-buffer))))))))
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	  (or (cdr dirs) (setq Info-dir-contents-directory
			       (file-name-as-directory (car dirs))))
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	  (setq dirs (cdr dirs))))
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      (or buffers
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	  (error "Can't find the Info directory node"))
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      ;; Distinguish the dir file that comes with Emacs from all the
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      ;; others.  Yes, that is really what this is supposed to do.
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      ;; The definition of `Info-directory-list' puts it first on that
      ;; list and so last in `buffers' at this point.
      (setq buffer (car (last buffers))
	    others (delq buffer buffers))
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      ;; Insert the entire original dir file as a start; note that we've
      ;; already saved its default directory to use as the default
      ;; directory for the whole concatenation.
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      (insert-buffer buffer)
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      ;; Look at each of the other buffers one by one.
      (while others
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	(let ((other (car others))
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	      ;; Bind this in case the user sets it to nil.
	      (case-fold-search t)
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	      this-buffer-nodes)
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	  ;; In each, find all the menus.
	  (save-excursion
	    (set-buffer other)
	    (goto-char (point-min))
	    ;; Find each menu, and add an elt to NODES for it.
	    (while (re-search-forward "^\\* Menu:" nil t)
	      (let (beg nodename end)
		(forward-line 1)
		(setq beg (point))
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		(or (search-backward "\n\^_" nil 'move)
		    (looking-at "\^_")
		    (signal 'search-failed (list "\n\^_")))
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		(search-forward "Node: ")
		(setq nodename (Info-following-node-name))
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		(search-forward "\n\^_" nil 'move)
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		(beginning-of-line)
		(setq end (point))
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		(setq this-buffer-nodes
		      (cons (list nodename other beg end)
			    this-buffer-nodes))))
	    (if (assoc-ignore-case "top" this-buffer-nodes)
		(setq nodes (nconc this-buffer-nodes nodes))
	      (setq problems t)
	      (message "No `top' node in %s" Info-dir-file-name))))
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	(setq others (cdr others)))
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      ;; Add to the main menu a menu item for each other node.
      (let ((case-fold-search t)
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	    (re-search-forward "^\\* Menu:")))
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      (forward-line 1)
      (let ((menu-items '("top"))
	    (nodes nodes)
	    (case-fold-search t)
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	    (end (save-excursion (search-forward "\^_" nil t) (point))))
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	(while nodes
	  (let ((nodename (car (car nodes))))
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	    (save-excursion
	      (or (member (downcase nodename) menu-items)
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		  (re-search-forward (concat "^\\* +"
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					     (regexp-quote nodename)
					     "::")
				     end t)
		  (progn
		    (insert "* " nodename "::" "\n")
		    (setq menu-items (cons nodename menu-items))))))
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	  (setq nodes (cdr nodes))))
      ;; Now take each node of each of the other buffers
      ;; and merge it into the main buffer.
      (while nodes
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	(let ((case-fold-search t)
	      (nodename (car (car nodes))))
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	  (goto-char (point-min))
	  ;; Find the like-named node in the main buffer.
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	  (if (re-search-forward (concat "^\^_.*\n.*Node: "
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					 (regexp-quote nodename)
					 "[,\n\t]")
				 nil t)
	      (progn
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		(search-forward "\n\^_" nil 'move)
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		(beginning-of-line)
		(insert "\n"))
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	    ;; If none exists, add one.
	    (goto-char (point-max))
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	    (insert "\^_\nFile: dir\tNode: " nodename "\n\n* Menu:\n\n"))
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	  ;; Merge the text from the other buffer's menu
	  ;; into the menu in the like-named node in the main buffer.
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	  (apply 'insert-buffer-substring (cdr (car nodes))))
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	(setq nodes (cdr nodes)))
      ;; Kill all the buffers we just made.
      (while buffers
	(kill-buffer (car buffers))
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	(setq buffers (cdr buffers)))
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      (goto-char (point-min))
      (if problems
	  (message "Composing main Info directory...problems encountered, see `*Messages*'")
	(message "Composing main Info directory...done")))
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    (setq Info-dir-contents (buffer-string)))
  (setq default-directory Info-dir-contents-directory))
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;; Note that on entry to this function the current-buffer must be the
;; *info* buffer; not the info tags buffer.
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(defun Info-read-subfile (nodepos)
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  ;; NODEPOS is either a position (in the Info file as a whole,
  ;; not relative to a subfile) or the name of a subfile.
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  (let (lastfilepos
	lastfilename)
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    (if (numberp nodepos)
	(save-excursion
	  (set-buffer (marker-buffer Info-tag-table-marker))
	  (goto-char (point-min))
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	  (or (looking-at "\^_")
	      (search-forward "\n\^_"))
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	  (forward-line 2)
	  (catch 'foo
	    (while (not (looking-at "\^_"))
	      (if (not (eolp))
		  (let ((beg (point))
			thisfilepos thisfilename)
		    (search-forward ": ")
		    (setq thisfilename  (buffer-substring beg (- (point) 2)))
		    (setq thisfilepos (read (current-buffer)))
		    ;; read in version 19 stops at the end of number.
		    ;; Advance to the next line.
		    (forward-line 1)
		    (if (> thisfilepos nodepos)
			(throw 'foo t))
		    (setq lastfilename thisfilename)
		    (setq lastfilepos thisfilepos))
		(forward-line 1)))))
      (setq lastfilename nodepos)
      (setq lastfilepos 0))
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    ;; Assume previous buffer is in Info-mode.
    ;; (set-buffer (get-buffer "*info*"))
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    (or (equal Info-current-subfile lastfilename)
	(let ((buffer-read-only nil))
	  (setq buffer-file-name nil)
	  (widen)
	  (erase-buffer)
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	  (info-insert-file-contents lastfilename)
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	  (set-buffer-modified-p nil)
	  (setq Info-current-subfile lastfilename)))
    (goto-char (point-min))
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    (if (looking-at "\^_")
	(forward-char 1)
      (search-forward "\n\^_"))
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    (if (numberp nodepos)
	(+ (- nodepos lastfilepos) (point)))))
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(defun Info-select-node ()
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"Select the info node that point is in.
Bind this in case the user sets it to nil."
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  (let ((case-fold-search t))
    (save-excursion
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      ;; Find beginning of node.
      (if (search-backward "\n\^_" nil 'move)
	  (forward-line 2)
	(if (looking-at "\^_")
	    (forward-line 1)
	  (signal 'search-failed (list "\n\^_"))))
      ;; Get nodename spelled as it is in the node.
      (re-search-forward "Node:[ \t]*")
      (setq Info-current-node
	    (buffer-substring-no-properties (point)
					    (progn
					      (skip-chars-forward "^,\t\n")
					      (point))))
      (Info-set-mode-line)
      ;; Find the end of it, and narrow.
      (beginning-of-line)
      (let (active-expression)
	(narrow-to-region (point)
			  (if (re-search-forward "\n[\^_\f]" nil t)
			      (prog1
				  (1- (point))
				(if (looking-at "[\n\^_\f]*execute: ")
				    (progn
				      (goto-char (match-end 0))
				      (setq active-expression
					    (read (current-buffer))))))
			    (point-max)))
	(if Info-enable-active-nodes (eval active-expression))
	(if Info-fontify (Info-fontify-node))
	(run-hooks 'Info-selection-hook)))))
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(defun Info-set-mode-line ()
  (setq mode-line-buffer-identification
	(concat
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	 "  *Info* ("
	 (file-name-nondirectory (if (stringp Info-current-file)
				     Info-current-file
				   (or buffer-file-name "")))
	 ") "
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	 (or Info-current-node ""))))

;; Go to an info node specified with a filename-and-nodename string
;; of the sort that is found in pointers in nodes.

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(defun Info-goto-node (nodename &optional fork)
  "Go to info node named NAME.  Give just NODENAME or (FILENAME)NODENAME.
If FORK is non-nil, show the node in a new info buffer.
If FORK is a string, it is the name to use for the new buffer."
  (interactive (list (Info-read-node-name "Goto node: ") current-prefix-arg))
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  (info-initialize)
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  (if fork
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      (set-buffer
       (clone-buffer (concat "*info-" (if (stringp fork) fork nodename) "*") t)))
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  (let (filename)
    (string-match "\\s *\\((\\s *\\([^\t)]*\\)\\s *)\\s *\\|\\)\\(.*\\)"
		  nodename)
    (setq filename (if (= (match-beginning 1) (match-end 1))
		       ""
		     (substring nodename (match-beginning 2) (match-end 2)))
	  nodename (substring nodename (match-beginning 3) (match-end 3)))
    (let ((trim (string-match "\\s *\\'" filename)))
      (if trim (setq filename (substring filename 0 trim))))
    (let ((trim (string-match "\\s *\\'" nodename)))
      (if trim (setq nodename (substring nodename 0 trim))))
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    (if transient-mark-mode (deactivate-mark))
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    (Info-find-node (if (equal filename "") nil filename)
		    (if (equal nodename "") "Top" nodename))))
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(defvar Info-read-node-completion-table)

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;; This function is used as the "completion table" while reading a node name.
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;; It does completion using the alist in Info-read-node-completion-table
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;; unless STRING starts with an open-paren.
(defun Info-read-node-name-1 (string predicate code)
  (let ((no-completion (and (> (length string) 0) (eq (aref string 0) ?\())))
    (cond ((eq code nil)
	   (if no-completion
	       string
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	     (try-completion string Info-read-node-completion-table predicate)))
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	  ((eq code t)
	   (if no-completion
	       nil
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	     (all-completions string Info-read-node-completion-table predicate)))
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	  ((eq code 'lambda)
	   (if no-completion
	       t
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	     (assoc string Info-read-node-completion-table))))))
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(defun Info-read-node-name (prompt &optional default)
  (let* ((completion-ignore-case t)
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	 (Info-read-node-completion-table (Info-build-node-completions))
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	 (nodename (completing-read prompt 'Info-read-node-name-1 nil t)))
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    (if (equal nodename "")
	(or default
	    (Info-read-node-name prompt))
      nodename)))

(defun Info-build-node-completions ()
  (or Info-current-file-completions
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      (let ((compl nil)
	    ;; Bind this in case the user sets it to nil.
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	    (case-fold-search t)
	    (node-regexp "Node: *\\([^,\n]*\\) *[,\n\t]"))
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	(save-excursion
	  (save-restriction
	    (if (marker-buffer Info-tag-table-marker)
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		(let ((marker Info-tag-table-marker))
		  (set-buffer (marker-buffer marker))
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		  (widen)
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		  (goto-char marker)
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		  (while (re-search-forward "\n\\(Node\\|Ref\\): \\(.*\\)\177" nil t)
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		    (setq compl
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			  (cons (list (match-string-no-properties 2))
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				compl))))
	      (widen)
	      (goto-char (point-min))
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	      ;; If the buffer begins with a node header, process that first.
	      (if (Info-node-at-bob-matching node-regexp)
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		  (setq compl (list (match-string-no-properties 1))))
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	      ;; Now for the rest of the nodes.
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	      (while (search-forward "\n\^_" nil t)
		(forward-line 1)
		(let ((beg (point)))
		  (forward-line 1)
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		  (if (re-search-backward node-regexp beg t)
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		      (setq compl
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			    (cons (list (match-string-no-properties 1))
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				  compl))))))))
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	(setq compl (cons '("*") compl))
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	(setq Info-current-file-completions compl))))
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(defun Info-restore-point (hl)
  "If this node has been visited, restore the point value when we left."
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  (while hl
    (if (and (equal (nth 0 (car hl)) Info-current-file)
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	     ;; Use string-equal, not equal, to ignore text props.
	     (string-equal (nth 1 (car hl)) Info-current-node))
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	(progn
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	  (goto-char (nth 2 (car hl)))
	  (setq hl nil))		;terminate the while at next iter
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      (setq hl (cdr hl)))))
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(defvar Info-search-history nil
  "The history list for `Info-search'.")
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(defun Info-search (regexp)
  "Search for REGEXP, starting from point, and select node it's found in."
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  (interactive (list (read-string "Regexp search: "
 				  nil 'Info-search-history)))
  (when transient-mark-mode
    (deactivate-mark))
  (when (equal regexp "")
    (setq regexp (car Info-search-history)))
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  (when regexp
    (let ((found ()) current
	  (onode Info-current-node)
	  (ofile Info-current-file)
	  (opoint (point))
	  (ostart (window-start))
	  (osubfile Info-current-subfile))
      (save-excursion
	(save-restriction
	  (widen)
	  (if (null Info-current-subfile)
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	      (progn (re-search-forward regexp) (setq found (point)))
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	    (condition-case err
		(progn (re-search-forward regexp) (setq found (point)))
	      (search-failed nil)))))
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      (if (not found)			;can only happen in subfile case -- else would have erred
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	  (unwind-protect
	      (let ((list ()))
		(save-excursion
		  (set-buffer (marker-buffer Info-tag-table-marker))
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		  (goto-char (point-min))
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		  (search-forward "\n\^_\nIndirect:")
		  (save-restriction
		    (narrow-to-region (point)
				      (progn (search-forward "\n\^_")
					     (1- (point))))
		    (goto-char (point-min))
		    (search-forward (concat "\n" osubfile ": "))
		    (beginning-of-line)
		    (while (not (eobp))
		      (re-search-forward "\\(^.*\\): [0-9]+$")
		      (goto-char (+ (match-end 1) 2))
		      (setq list (cons (cons (read (current-buffer))
1056
					     (match-string-no-properties 1))