;;;; texnfo-upd.el
;;;; A utility for updating nodes and menus in Texinfo files.

;;;; Robert J. Chassell, 23 September 1989; 15 May 1990

;;;; Copyright 1989, 1990 Free Software Foundation

;; 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
;; the Free Software Foundation; either version 1, or (at your option)
;; 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
;; along with GNU Emacs; see the file COPYING.  If not, write to
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

(provide 'texnfo-upd)


;;;; Summary

; (Much of the following commentary ought eventually be incorporated
; into the Texinfo Manual.)

; The node and menu updating functions automatically

;   * insert missing `@node' lines,
;   * insert the `Next', `Previous' and `Up' pointers of a node,
;   * insert or update the menu for a section, 
;   * create a master menu for a Texinfo source file.

; Passed an argument, the `texinfo-update-node' and
; `texinfo-make-menu' functions do their jobs in the region.

; These functions replace doing these jobs by hand.
; You may find them helpful.

; In brief, the functions for creating or updating nodes and menus, are:
; 
;     texinfo-update-node (&optional region-p)            
;     texinfo-every-node-update ()                        
;     texinfo-sequential-node-update (&optional region-p)
; 
;     texinfo-make-menu (&optional region-p)              
;     texinfo-all-menus-update ()                         
;     texinfo-master-menu ()
;
;     texinfo-insert-node-lines  (&optional title-p)
; 
;     texinfo-indent-menu-description (column &optional region-p)

; The `texinfo-column-for-description' variable specifies the column to
; which menu descriptions are indented. 

; Texinfo file structure
; ----------------------

; To use the updating commands, you must structure your Texinfo file
; hierarchically.  Each `@node' line, with the exception of the top
; node, must be accompanied by some kind of section line, such as an
; `@chapter' or `@section' line.  Each node-line/section-line
; combination must look like this:

;      @node    Lists and Tables, Cross References, Structuring, Top
;      @comment node-name,        next,             previous,    up
;      @chapter Making Lists and Tables

; or like this (without the `@comment' line):

;      @node    Lists and Tables, Cross References, Structuring, Top
;      @chapter Making Lists and Tables

; If the file has a `top' node, it must be called `top' or `Top' and
; be the first node in the file.


;;;; The updating functions in detail
;    --------------------------------

; The `texinfo-update-node' function without an argument inserts
; the correct next, previous and up pointers for the node in which
; point is located (i.e., for the node preceding point).

; With an argument, the `texinfo-update-node' function inserts the
; correct next, previous and up pointers for the nodes inside the
; region.

; It does not matter whether the  `@node' line has pre-existing
; `Next', `Previous', or `Up' pointers in it.  They are removed.

; The `texinfo-every-node-update' function runs `texinfo-update-node'
; on the whole buffer.

; The `texinfo-update-node' function inserts the immediately following
; and preceding node into the `Next' or `Previous' pointers regardless
; of their hierarchical level.  This is only useful for certain kinds
; of text, like a novel, which you go through sequentially.  

; The `texinfo-make-menu' function without an argument creates or
; updates a menu for the section encompassing the node that follows
; point.  With an argument, it makes or updates menus for the nodes
; within or part of the marked region.

; Whenever an existing menu is updated, the descriptions from
; that menu are incorporated into the new menu.  This is done by copying
; descriptions from the existing menu to the entries in the new menu
; that have the same node names.  If the node names are different, the
; descriptions are not copied to the new menu.

; Menu entries that refer to other Info files are removed since they
; are not a node within current buffer.  This is a deficiency.

; The `texinfo-all-menus-update' function runs `texinfo-make-menu'
; on the whole buffer.

; The `texinfo-master-menu' function creates an extended menu located
; after the top node.  (The file must have a top node.)  The function
; first updates all the regular menus in the buffer (incorporating the
; descriptions from pre-existing menus), and then constructs a master
; menu that includes every entry from every other menu.  (However, the
; function cannot update an already existing master menu; if one
; exists, it must be removed before calling the function.)

; The `texinfo-indent-menu-description' function indents every
; description in the menu following point, to the specified column.
; Non-nil argument (prefix, if interactive) means indent every
; description in every menu in the region.  This function does not
; indent second and subsequent lines of a multi-line description.

; The `texinfo-insert-node-lines' function inserts `@node' before the
; `@chapter', `@section', and such like lines of a region in a Texinfo
; file where the `@node' lines are missing.
; 
; With a non-nil argument (prefix, if interactive), the function not
; only inserts `@node' lines but also inserts the chapter or section
; titles as the names of the corresponding nodes; and inserts titles
; as node names in pre-existing `@node' lines that lack names.
; 
; Since node names should be more concise than section or chapter
; titles, node names so inserted will need to be edited manually.

 
;;;; Menu Making Functions

(defun texinfo-make-menu (&optional region-p)
  "Without any prefix argument, make or update a menu.
Make the menu for the section enclosing the node found following point.

Non-nil argument (prefix, if interactive) means make or update menus
for nodes within or part of the marked region.

Whenever a menu exists, and is being updated, the descriptions that
are associated with node names in the pre-existing menu are
incorporated into the new menu.  Otherwise, the nodes' section titles
are inserted as descriptions."
  
  (interactive "P")
  (if (not region-p)
      (let ((level (texinfo-hierarchic-level)))
        (texinfo-make-one-menu level)
        (message "Done...updated the menu.  You may save the buffer."))
    ;; else
    (message "Making or updating menus... ")
    (let ((beginning (region-beginning))
	  (region-end (region-end))
          (level (progn         ; find section type following point
                   (goto-char (region-beginning))
                   (texinfo-hierarchic-level))))
      (if (= region-end beginning)
          (error "Please mark a region!"))
      (save-excursion
        (save-restriction
          (widen)
          
          (while  (texinfo-find-lower-level-node level region-end)
            (setq level (texinfo-hierarchic-level)) ; new, lower level
            (texinfo-make-one-menu level))
          
          (while (and (< (point) region-end)
                      (texinfo-find-higher-level-node level region-end))
            (setq level (texinfo-hierarchic-level))
            (while (texinfo-find-lower-level-node level region-end)
              (setq level (texinfo-hierarchic-level)) ; new, lower level
              (texinfo-make-one-menu level))))))
    (message "Done...updated menus.  You may save the buffer.")))

(defun texinfo-make-one-menu (level)
  "Make a menu of all the appropriate nodes in this section.
`Appropriate nodes' are those associated with sections that are 
at the level specified by LEVEL.  Point is left at the end of menu."
  (let*
      ((case-fold-search t)
       (beginning (texinfo-update-menu-region-beginning level))
       (end (texinfo-update-menu-region-end level))
       (first (texinfo-menu-first-node beginning end))
       (node-name (progn
                    (goto-char beginning)
                    (texinfo-copy-node-name)))
       (new-menu-list (texinfo-make-menu-list beginning end level)))
    (if (texinfo-old-menu-p beginning first)
        (progn
          (texinfo-incorporate-descriptions new-menu-list)
          (texinfo-delete-old-menu beginning first)))
    (texinfo-insert-menu new-menu-list node-name)))

(defun texinfo-all-menus-update (&optional update-all-nodes-p)
  "Update every regular menu in a Texinfo file.
You must remove the detailed part of a pre-existing master menu before
running this command, lest it be partly duplicated.

If called with a non-nil argument, this function first updates all the
nodes in the buffer before updating the menus."
  (interactive "P")
  (save-excursion
    (mark-whole-buffer)
    (message "Checking for a master menu... ")
    (save-excursion
      (if (re-search-forward texinfo-master-menu-header nil t)
          (error
           "Please remove existing master menu, lest it be partly duplicated!")))

  (if update-all-nodes-p
      (progn
        (message "First updating all nodes... ")
        (sleep-for 2)
        (mark-whole-buffer)
        (texinfo-update-node t)))

    (message "Updating all menus... ")
    (sleep-for 2)
    (texinfo-make-menu t)
    (message "Done...updated all the menus.  You may save the buffer.")))

(defun texinfo-find-lower-level-node (level region-end)
  "Search forward from point for node at any level lower than LEVEL.
Search is limited to the end of the marked region, REGION-END, 
and to the end of the menu region for the level.

Return t if the node is found, else nil.  Leave point at the beginning
of the node if one is found; else do not move point."

  (if (and (< (point) region-end)
           (re-search-forward
            (concat
             "\\(^@node\\).*\n"         ; match node line
             "\\(\\(^@c\\).*\n\\)?"     ; match comment line, if any
             (eval (cdr (assoc level texinfo-update-menu-lower-regexps))))
            ;; the next higher level node marks the end of this
            ;; section, and no lower level node will be found beyond
            ;; this position even if region-end is farther off
            (texinfo-update-menu-region-end level) 
            t))
      (goto-char (match-beginning 1))))

(defun texinfo-find-higher-level-node (level region-end)
  "Search forward from point for node at any higher level than argument LEVEL.
Search is limited to the end of the marked region, REGION-END.

Return t if the node is found, else nil.  Leave point at the beginning
of the node if one is found; else do not move point."

  (if (and (< (point) region-end)
           (re-search-forward
            (concat
             "\\(^@node\\).*\n"         ; match node line
             "\\(\\(^@c\\).*\n\\)?"     ; match comment line, if any
             (eval                      ; (won't ever find a `top' node)
              (cdr (assoc level texinfo-update-menu-higher-regexps))))
            nil
            t))
      (goto-char (match-beginning 1))))


;;;; Making the list of new menu entries

(defun texinfo-make-menu-list (beginning end level)
  "Make a list of node names and their descriptions.
Point is left at the end of the menu region, but the menu is not inserted.

First argument is position from which to start making menu list; 
second argument is end of region in which to try to locate entries;
third argument is the level of the nodes that are the entries.

Node names and descriptions are dotted pairs of strings.  Each pair is
an element of the list.  If the description does not exist, the
element consists only of the node name."
  (goto-char beginning)
  (let (new-menu-list)
    (while (texinfo-menu-locate-entry-p level end)
      (setq new-menu-list 
            (cons (cons 
                   (texinfo-copy-node-name)
                   (texinfo-copy-section-title))
                  new-menu-list)))
    (reverse new-menu-list)))

(defun texinfo-menu-locate-entry-p (level search-end)
  "Find a node that will be part of menu for this section.
First argument is a string such as \"section\" specifying the general
hierarchical level of the menu; second argument is a postion
specifying the end of the search.

The function returns t if the node is found, else nil.  It searches
forward from point, and leaves point at the beginning of the node.

The function finds entries of the same type.  Thus `subsections' and
`unnumberedsubsecs' will appear in the same menu."
  (if (re-search-forward
       (concat
        "\\(^@node\\).*\n"            ; match node line
        "\\(\\(^@c\\).*\n\\)?"        ; match comment line, if any
        (eval
         (cdr (assoc level texinfo-update-menu-same-level-regexps))))
       search-end
       t)
      (goto-char (match-beginning 1))))

(defun texinfo-copy-node-name ()
  "Return the node name as a string.

Start with point at the beginning of the node line; copy the text
after the node command up to the first comma on the line, if any, and
return the text as a string.  Leaves point at the beginning of the
line.  If there is no node name, returns an empty string."
  
  (save-excursion
    (buffer-substring
     (progn (forward-word 1)              ; skip over node command
            (skip-chars-forward " \t")    ; and over spaces
            (point))
     (if (search-forward
          ","
          (save-excursion (end-of-line) (point)) t) ; bound search
         (1- (point))
       (end-of-line) (point)))))

(defun texinfo-copy-section-title ()
  "Return the title of the section as a string.
The title is used as a description line in the menu when one does not
already exist.

Move point to the beginning of the appropriate section line by going
to the start of the text matched by last regexp searched for, which
must have been done by `texinfo-menu-locate-entry-p'."

  ;; could use the same re-search as in `texinfo-menu-locate-entry-p'
  ;; instead of using `match-beginning'; such a variation would be
  ;; more general, but would waste information already collected

  (goto-char (match-beginning 4))       ; match section name 

  (buffer-substring
   (progn (forward-word 1)              ; skip over section type
          (skip-chars-forward " \t")    ; and over spaces
          (point))
   (progn (end-of-line) (point))))


;;;; Handling the old menu

(defun texinfo-old-menu-p (beginning first)
  "Move point to the beginning of the menu for this section, if any.
Otherwise move point to the end of the first node of this section.
Return t if a menu is found, nil otherwise.

First argument is the position of the beginning of the section in which
the menu will be located; second argument is the position of the first
node within the section.

If no menu is found, the function inserts two newlines just before the
end of the section, and leaves point there where a menu ought to be."
  (goto-char beginning)
  (if (not (re-search-forward "^@menu" first 'goto-end))
      (progn (insert "\n\n") (forward-line -2) nil)
    t))

(defun texinfo-incorporate-descriptions (new-menu-list)
  "Copy the old menu line descriptions that exist to the new menu.

Point must be at beginning of old menu.

If the node-name of the new menu entry cannot be found in the old
menu, use the new section title for the description, but if the
node-name of the new menu is found in the old menu, replace the
section title with the old description, whatever it may be.

For this function, the new menu is a list made up of lists of dotted
pairs in which the first element of the pair is the node name and the
second element the description. The new menu is changed destructively.
The old menu is the menu as it appears in the texinfo file."
  
  (let ((new-menu-list-pointer new-menu-list)
        (end-of-menu (texinfo-menu-end)))
    (while new-menu-list
      (save-excursion                   ; keep point at beginning of menu 
        (if (search-forward
             (concat "\* "              ; so only menu entries are found
                     (car (car new-menu-list)))
             end-of-menu
             t) 
            (setcdr (car new-menu-list) 
                    (texinfo-menu-copy-old-description end-of-menu))))
      (setq new-menu-list (cdr new-menu-list))) 
    (setq new-menu-list new-menu-list-pointer)))

(defun texinfo-menu-copy-old-description (end-of-menu)
  "Return description field of old menu line as string.
Point must be located just after the node name.  Point left before description.
Single argument, END-OF-MENU, is position limiting search."
  (skip-chars-forward "[:.,\t\n ]+")
  ;; don't copy a carriage return at line beginning with asterisk!
  ;; do copy a description that begins with an `@'!
  (if (and (looking-at "\\(\\w+\\|@\\)")    
           (not (looking-at "\\(^\\* \\|^@end menu\\)")))  
      (buffer-substring
       (point)
       (save-excursion
         (re-search-forward "\\(^\\* \\|^@end menu\\)" end-of-menu t)
         (forward-line -1)
         (end-of-line)                  ; go to end of last description line
         (point)))
    ""))

(defun texinfo-menu-end ()
  "Return position of end of menu. Does not change location of point.
Signal an error if not end of menu."
  (save-excursion
    (if (re-search-forward "^@end menu" nil t)
        (point)
      (error "Menu does not have an end."))))

(defun texinfo-delete-old-menu (beginning first)
  "Delete the old menu.  Point must be in or after menu.
First argument is position of the beginning of the section in which
the menu will be located; second argument is the position of the first
node within the section."
  ;; No third arg to search, so error if search fails.
  (re-search-backward "^@menu" beginning)
  (delete-region (point)
                 (save-excursion
                   (re-search-forward "^@end menu" first)
                   (point))))


;;;; Inserting new menu

;; try 32, but perhaps 24 is better
(defvar texinfo-column-for-description 32
  "*Column at which descriptions start in a Texinfo menu.")

(defun texinfo-insert-menu (menu-list node-name)
  "Insert formatted menu at point.
Indents the first line of the description, if any, to the value of
texinfo-column-for-description.

MENU-LIST has form:

    \(\(\"node-name1\" . \"description\"\) 
    \(\"node-name\" . \"description\"\) ... \)

However, there does not need to be a description field."
  
  (insert "@menu\n")
  (while menu-list
    (if (cdr (car menu-list))       ; menu-list has description entry
        (progn
          (insert 
           (format "* %s::" (car (car menu-list)))) ; node-name entry
          (indent-to texinfo-column-for-description 2)
          (insert 
           (format "%s\n" (cdr (car menu-list)))))  ; description entry
        ;; else menu-list lacks description entry
      (insert
       (format "* %s::\n" (car (car menu-list)))))  ; node-name entry
    (setq menu-list (cdr menu-list)))
  (insert "@end menu")
  (message
   "Updated \"%s\" level menu following node: %s ... "
   level node-name))


;;;; Handling description indentation

; Since the make-menu functions indent descriptions, these functions
; are useful primarily for indenting a single menu specially.

(defun texinfo-indent-menu-description (column &optional region-p)
  "Indent every description in menu following point to COLUMN.  
Non-nil argument (prefix, if interactive) means indent every
description in every menu in the region.  Does not indent second and
subsequent lines of a multi-line description."
  
  (interactive
   "nIndent menu descriptions to (column number): \nP")
  (save-excursion
    (save-restriction
      (widen)
      (if (not region-p)
          (progn
            (re-search-forward "^@menu")
            (texinfo-menu-indent-description column)
            (message
             "Indented descriptions in menu.  You may save the buffer."))
        ;;else
        (message "Indenting every menu description in region... ")
        (goto-char (region-beginning))
        (while (and (< (point) (region-end))
                    (texinfo-locate-menu-p))
          (forward-line 1)
          (texinfo-menu-indent-description column))
        (message "Indenting done.  You may save the buffer.")))))

(defun texinfo-menu-indent-description (to-column-number)
  "Indent the Texinfo file menu description to TO-COLUMN-NUMBER.
Start with point just after the word `menu' in the `@menu' line and
leave point on the line before the `@end menu' line.  Does not indent
second and subsequent lines of a multi-line description."
  (let* ((beginning-of-next-line (point)))
    (while (< beginning-of-next-line
              (save-excursion     ; beginning of end menu line
                (goto-char (texinfo-menu-end))
                (beginning-of-line)
                (point)))
      (if (search-forward "::" (texinfo-menu-end) t)
          (progn
            (let ((beginning-white-space (point)))
              (skip-chars-forward " \t")  ; skip over spaces
              (if (looking-at "\\(@\\|\\w\\)+") ; if there is text
                  (progn
                    ;; remove pre-existing indentation
                    (delete-region beginning-white-space (point))
                    (indent-to-column to-column-number))))))
      ;; position point at beginning of next line
      (forward-line 1)                  
      (setq beginning-of-next-line (point)))))


;;;; Making the master menu

(defun texinfo-master-menu (update-all-nodes-menus-p)
  "Make a master menu for a whole Texinfo file.
Non-nil argument (prefix, if interactive) means first update all
existing nodes and menus.  Remove pre-existing master menu, if there is one.

This function creates a master menu that follows the top node.  The
master menu includes every entry from all the other menus.  It
replaces any existing ordinary menu that follows the top node.

If called with a non-nil argument, this function first updates all the
menus in the buffer (incorporating descriptions from pre-existing
menus) before it constructs the master menu.

The function removes the detailed part of an already existing master
menu.  This action depends on the pre-exisitng master menu using the
standard `texinfo-master-menu-header'.

The master menu has the following format, which is adapted from the
recommendation in the Texinfo Manual:

   * The first part contains the major nodes in the Texinfo file: the
     nodes for the chapters, chapter-like sections, and the major
     appendices.  This includes the indices, so long as they are in
     chapter-like sections, such as unnumbered sections.

   * The second and subsequent parts contain a listing of the other,
     lower level menus, in order.  This way, an inquirer can go
     directly to a particular node if he or she is searching for
     specific information.

Each of the menus in the detailed node listing is introduced by the
title of the section containing the menu."

  (interactive "P")
  (widen)
  (goto-char (point-min))

  ;; Move point to location after `top'.
  (if (not (re-search-forward "^@node [ \t]*top" nil t))
      (error "This buffer needs a Top node!"))

  (let ((first-chapter                  
         (save-excursion (re-search-forward "^@node") (point))))
    (if (re-search-forward texinfo-master-menu-header first-chapter t)
        ;; Remove detailed master menu listing
        (progn
           (goto-char (match-beginning 0))
          (let ((end-of-detailed-menu-descriptions
                 (save-excursion     ; beginning of end menu line
                   (goto-char (texinfo-menu-end))
                   (beginning-of-line) (forward-char -1)
                   (point))))
            (delete-region (point) end-of-detailed-menu-descriptions)))))

  (if update-all-nodes-menus-p
      (progn
        (message "Making a master menu...first updating all nodes... ")
        (sleep-for 2)
        (mark-whole-buffer)
        (texinfo-update-node t)

        (message "Updating all menus... ")        
        (sleep-for 2)
        (mark-whole-buffer)
        (texinfo-make-menu t)))

  (message "Now making the master menu... ")
  (sleep-for 2)
  (goto-char (point-min))
  (texinfo-insert-master-menu-list
   (texinfo-master-menu-list))

  ;; Remove extra newlines that texinfo-insert-master-menu-list
  ;; may have inserted.

  (save-excursion
    (goto-char (point-min))
    
    (re-search-forward texinfo-master-menu-header)
    (goto-char (match-beginning 0))
    (insert "\n")
    (delete-blank-lines)
    
    (re-search-backward "^@menu")
    (forward-line -1)
    (delete-blank-lines)
    
    (re-search-forward "^@end menu")
    (forward-line 1)
    (delete-blank-lines))

  (message "Done...completed making master menu.  You may save the buffer."))

(defun texinfo-master-menu-list ()
  "Return a list of menu entries and header lines for the master menu.

Start with the menu for chapters and indices and then find each
following menu and the title of the node preceding that menu.

The master menu list has this form:

    \(\(\(... \"entry-1-2\"  \"entry-1\"\) \"title-1\"\)
      \(\(... \"entry-2-2\"  \"entry-2-1\"\) \"title-2\"\)
      ...\)

However, there does not need to be a title field."

  (let (master-menu-list)
    (while (texinfo-locate-menu-p)
      (setq master-menu-list 
            (cons (list
                   (texinfo-copy-menu)
                   (texinfo-copy-menu-title))
                  master-menu-list)))
    (reverse master-menu-list)))

(defun texinfo-insert-master-menu-list (master-menu-list)
  "Format and insert the master menu in the current buffer."
  (goto-char (point-min))
  (re-search-forward "^@menu")
  (beginning-of-line)
  (delete-region (point)        ; buffer must have ordinary top menu
                 (save-excursion
                   (re-search-forward "^@end menu")
                   (point)))

  (save-excursion                       ; leave point at beginning of menu
  ;; Handle top of menu
  (insert "\n@menu\n")
  ;; Insert chapter menu entries
  (setq this-very-menu-list (reverse (car (car master-menu-list))))
  ;;; Tell user what is going on.
  (message "Inserting chapter menu entry: %s ... " this-very-menu-list)
  (while this-very-menu-list
    (insert "* " (car this-very-menu-list) "\n")
    (setq this-very-menu-list (cdr this-very-menu-list)))
  
  (setq master-menu-list (cdr master-menu-list))

  (insert texinfo-master-menu-header)
  
  ;; Now, insert all the other menus

  ;; The menu master-menu-list has a form like this:
  ;; ((("beta"  "alpha") "title-A")
  ;;  (("delta" "gamma") "title-B"))

  (while master-menu-list

    (message
     "Inserting menu for %s .... " (car (cdr (car master-menu-list))))
    ;; insert title of menu section
    (insert "\n" (car (cdr (car master-menu-list))) "\n\n")

    ;; insert each menu entry
    (setq this-very-menu-list (reverse (car (car master-menu-list))))
    (while this-very-menu-list
      (insert "* " (car this-very-menu-list) "\n")
      (setq this-very-menu-list (cdr this-very-menu-list)))
    
    (setq master-menu-list (cdr master-menu-list)))
  
  ;; Finish menu
  (insert "@end menu\n\n")))

(defvar texinfo-master-menu-header
  "\n --- The Detailed Node Listing ---\n"
  "String inserted before lower level entries in Texinfo master menu.
It comes after the chapter-level menu entries.")

(defun texinfo-locate-menu-p ()
  "Find the next menu in the texinfo file.
If found, leave point after word `menu' on the `@menu' line, and return t.
If a menu is not found, do not move point and return nil."
  (re-search-forward "\\(^@menu\\)" nil t))

(defun texinfo-copy-menu-title  ()
  "Return the title of the section preceding the menu as a string.
If such a title cannot be found, return an empty string.  Do not move
point."
  (save-excursion
    (if (re-search-backward
         (concat
          "\\(^@node\\).*\n"            ; match node line
          "\\(\\(^@c\\).*\n\\)?"        ; match comment line, if any
          (eval
           (cdr
            (assoc (texinfo-hierarchic-level)
                   texinfo-update-menu-higher-regexps))))
         nil
         t)
        (texinfo-copy-section-title)
      " ")))

(defun texinfo-copy-menu ()
  "Return the entries of an existing menu as a list.
Start with point just after the word `menu' in the `@menu' line
and leave point on the line before the `@end menu' line."
  (let* (this-menu-list
         (end-of-menu (texinfo-menu-end)) ; position of end of `@end menu'
         (last-entry (save-excursion      ; position of beginning of
                                          ; last `* ' entry
                      (goto-char end-of-menu)
                      (re-search-backward "^\* ") ; handle multi-line desc.
                      (point))))
    (while (< (point) last-entry)
      (if (re-search-forward  "^\* " end-of-menu t)
          (progn
            (setq this-menu-list
                  (cons
                   (buffer-substring 
                    (point)
                    ;; copy multi-line descriptions
                    (save-excursion
                      (re-search-forward "\\(^\* \\|^@e\\)" nil t)
                      (- (point) 3)))
                   this-menu-list)))))
    this-menu-list))


;;;; Determining the hierarchical level in the texinfo file

(defun texinfo-specific-section-type () 
  "Return the specific type of next section, as a string.
For example, \"unnumberedsubsec\".  Return \"top\" for top node.

Searches forward for a section.  Hence, point must be before the
section whose type will be found.  Does not move point.  Signal an
error if the node is not the top node and a section is not found."
  (save-excursion
    (cond
     ((re-search-forward "^@node [ \t]*top" nil t)
      "top")
     ((re-search-forward texinfo-section-types-regexp nil t)
      (buffer-substring (progn (beginning-of-line) ; copy its name
                               (1+ (point)))
                        (progn (forward-word 1)
                               (point))))
     (t
      (error
       "texinfo-specific-section-type: Chapter or section not found.")))))

(defun texinfo-hierarchic-level ()
  "Return the general hierarchal level of the next node in a texinfo file.
Thus, a subheading or appendixsubsec is of type subsection."
  (cdr (assoc
        (texinfo-specific-section-type)
        texinfo-section-to-generic-alist)))


;;;; Locating the major positions

(defun texinfo-update-menu-region-beginning (level)  
  "Locate beginning of higher level section this section is within.
Return position of the beginning of the node line; do not move point.
Thus, if this level is subsection, searches backwards for section node.
Only argument is a string of the general type of section."
  
  (cond
   ((string-equal "top" level)
    (save-excursion
      (re-search-forward "^@node [ \t]*top" nil t) (point)))
   ((string-equal "chapter" level)
    (save-excursion
      (re-search-backward "^@node [ \t]*top" nil t) (point)))
   (t
    (save-excursion
      (re-search-backward
       (concat
        "\\(^@node\\).*\n"            ; match node line
        "\\(\\(^@c\\).*\n\\)?"        ; match comment line, if any
        (eval
         (cdr (assoc level texinfo-update-menu-higher-regexps))))
       nil
       'goto-beginning)
      (point)))))

(defun texinfo-update-menu-region-end (level)  
  "Locate end of higher level section this section is within.
Return position; do not move point.  Thus, if this level is a
subsection, find the node for the section this subsection is within.
If level is top or chapter, returns end of file.  Only argument is a
string of the general type of section."

  (save-excursion
    (if (re-search-forward
         (concat
          "\\(^@node\\).*\n"            ; match node line
          "\\(\\(^@c\\).*\n\\)?"        ; match comment line, if any
          (eval
           (cdr (assoc level texinfo-update-menu-higher-regexps))))
         nil
         'goto-end)
        (match-beginning 1)
      (point-max))))

(defun texinfo-menu-first-node (beginning end)
  "Locate first node of the section the menu will be placed in.  
Return position; do not move point.
The menu will be located just before this position.  

First argument is the position of the beginning of the section in
which the menu will be located; second argument is the position of the
end of that region; it limits the search."
  
  (save-excursion
    (goto-char beginning)
    (forward-line 1)
    (re-search-forward "^@node" end t)
    (beginning-of-line)
    (point)))


;;;; Alists and regular expressions for defining hierarchical levels

(defvar texinfo-section-to-generic-alist
  '(("top" . "top")

    ("chapter" . "chapter")
    ("unnumbered" . "chapter")
    ("majorheading" . "chapter")
    ("chapheading" . "chapter")
    ("appendix" . "chapter")
    
    ("section" . "section")
    ("unnumberedsec" . "section")
    ("heading" . "section")
    ("appendixsec" . "section")
    
    ("subsection" . "subsection")
    ("unnumberedsubsec" . "subsection")
    ("subheading" . "subsection")
    ("appendixsubsec" . "subsection")
    
    ("subsubsection" . "subsubsection")
    ("unnumberedsubsubsec" . "subsubsection")
    ("subsubheading" . "subsubsection")
    ("appendixsubsubsec" . "subsubsection"))
  "*An alist of specific and corresponding generic Texinfo section types.
The keys are strings specifying specific types of section; the values
are strings of their corresponding general types.")

(defvar texinfo-section-types-regexp
  "^@\\(chapter \\|sect\\|sub\\|unnum\\|major\\|heading \\|appendix\\)"
  "Regexp matching chapter, section, other headings (but not the top node).")

(defvar texinfo-chapter-level-regexp 
  "chapter\\|unnumbered \\|appendix \\|majorheading\\|chapheading"
  "Regular expression matching just the Texinfo chapter level headings.")

(defvar texinfo-section-level-regexp 
  "section\\|unnumberedsec\\|heading \\|appendixsec"
  "Regular expression matching just the Texinfo section level headings.")

(defvar texinfo-subsection-level-regexp 
  "subsection\\|unnumberedsubsec\\|subheading\\|appendixsubsec"
  "Regular expression matching just the Texinfo subsection level headings.")

(defvar texinfo-subsubsection-level-regexp
  "subsubsection\\|unnumberedsubsubsec\\|subsubheading\\|appendixsubsubsec"
  "Regular expression matching just the Texinfo subsubsection level headings.")

(defvar texinfo-update-menu-same-level-regexps
  '(("top" . "top[ \t]+")
    ("chapter" . 
     (concat "\\(^@\\)\\(" texinfo-chapter-level-regexp "\\)[ \t]*"))
    ("section" . 
     (concat "\\(^@\\)\\(" texinfo-section-level-regexp "\\)[ \t]*"))
    ("subsection" .  
     (concat "\\(^@\\)\\(" texinfo-subsection-level-regexp "\\)[ \t]+"))
    ("subsubsection" . 
     (concat "\\(^@\\)\\(" texinfo-subsubsection-level-regexp "\\)[ \t]+")))
  "*Regexps for searching for same level sections in a Texinfo file.
The keys are strings specifying the general hierarchical level in the
document; the values are regular expressions.")

(defvar texinfo-update-menu-higher-regexps
  '(("top" . "^@node [ \t]*DIR") 
    ("chapter" . "^@node [ \t]*top")
    ("section" .
     (concat 
      "\\(^@\\("
      texinfo-chapter-level-regexp
      "\\)[ \t]*\\)"))
    ("subsection" .
     (concat 
      "\\(^@\\("
      texinfo-section-level-regexp
      "\\|"
      texinfo-chapter-level-regexp
      "\\)[ \t]*\\)"))
    ("subsubsection" .
     (concat 
      "\\(^@\\("
      texinfo-subsection-level-regexp
      "\\|"
      texinfo-section-level-regexp
      "\\|"
      texinfo-chapter-level-regexp
      "\\)[ \t]*\\)")))
  "*Regexps for searching for higher level sections in a Texinfo file.
The keys are strings specifying the general hierarchical level in the
document; the values are regular expressions.")

(defvar texinfo-update-menu-lower-regexps
  '(("top" . 
     (concat 
      "\\(^@\\("
      texinfo-chapter-level-regexp
      "\\|"
      texinfo-section-level-regexp
      "\\|"
      texinfo-subsection-level-regexp
      "\\|"
      texinfo-subsubsection-level-regexp
      "\\)[ \t]*\\)"))
    ("chapter" . 
     (concat 
      "\\(^@\\("
      texinfo-section-level-regexp
      "\\|"
      texinfo-subsection-level-regexp
      "\\|"
      texinfo-subsubsection-level-regexp
      "\\)[ \t]*\\)"))
    ("section" .
     (concat 
      "\\(^@\\("
      texinfo-subsection-level-regexp
      "\\|"
      texinfo-subsubsection-level-regexp
      "\\)[ \t]+\\)"))
    ("subsection" .
     (concat 
      "\\(^@\\("
      texinfo-subsubsection-level-regexp
      "\\)[ \t]+\\)"))
    ("subsubsection" . "nothing lower"))
  "*Regexps for searching for lower level sections in a Texinfo file.
The keys are strings specifying the general hierarchical level in the
document; the values are regular expressions.")


;;;; Updating a Node

(defun texinfo-update-node (&optional region-p)
  "Without any prefix argument, update the node in which point is located.
Non-nil argument (prefix, if interactive) means update the nodes in the
marked region.

The functions for creating or updating nodes and menus, and their
keybindings, are:

    texinfo-update-node (&optional region-p)    \\[texinfo-update-node]
    texinfo-every-node-update ()                \\[texinfo-every-node-update]
    texinfo-sequential-node-update (&optional region-p)

    texinfo-make-menu (&optional region-p)      \\[texinfo-make-menu]
    texinfo-all-menus-update ()                 \\[texinfo-all-menus-update]
    texinfo-master-menu ()

    texinfo-indent-menu-description (column &optional region-p)

The `texinfo-column-for-description' variable specifies the column to
which menu descriptions are indented. Its default value is 24."
  
  (interactive "P")
  (if (not region-p)
      (let ((auto-fill-hook nil)) ; update a single node
        (if (not (re-search-backward "^@node" (point-min) t))
            (error "Node line not found before this position."))
        (texinfo-update-the-node)
        (message "Done...updated the node.  You may save the buffer."))
    ;; else
    (let ((auto-fill-hook nil)
          (beginning (region-beginning))
	  (end (region-end)))
      (if (= end beginning)
          (error "Please mark a region!"))
      (save-restriction
	(narrow-to-region beginning end)
	(goto-char beginning)
        (push-mark)
	(while (re-search-forward "^@node" (point-max) t)
          (beginning-of-line)            
          (texinfo-update-the-node))
        (message "Done...updated nodes in region.  You may save the buffer.")))))

(defun texinfo-every-node-update ()
  "Update every node in a Texinfo file."
  (interactive)
  (save-excursion
    (mark-whole-buffer)
    (texinfo-update-node t)
    (message "Done...updated every node.       You may save the buffer.")))

(defun texinfo-update-the-node ()
  "Update one node.  Point must be at the beginning of node line.  
Leave point at the end of the node line."
  (texinfo-check-for-node-name)
  (texinfo-delete-existing-pointers)
  (message "Updating node: %s ... " (texinfo-copy-node-name))
  (save-restriction
    (widen)
    (let*
        ((case-fold-search t)
         (level (texinfo-hierarchic-level))
         (beginning (texinfo-update-menu-region-beginning level))
         (end (texinfo-update-menu-region-end level)))
      (if (string-equal level "top")
          (texinfo-top-pointer-case)
        ;; else
        (texinfo-insert-pointer beginning end level 'next)
        (texinfo-insert-pointer beginning end level 'previous)
        (texinfo-insert-pointer beginning end level 'up)
        (texinfo-clean-up-node-line)))))

(defun texinfo-top-pointer-case ()
  "Insert pointers in the Top node.  This is a special case.

The `Next' pointer is a pointer to a chapter or section at a lower
hierarchical level in the file.  The `Previous' and `Up' pointers are
to `(dir)'.  Point must be at the beginning of the node line, and is
left at the end of the node line."

  (texinfo-clean-up-node-line)
  (insert ", " 
          (save-excursion
            ;; There may be an @chapter or other such command between
            ;; the top node line and the next node line, as a title
            ;; for an `ifinfo' section. This @chapter command must
            ;; must be skipped.  So the procedure is to search for
            ;; the next `@node' line, and then copy its name.
            (if (re-search-forward "^@node" nil t)
                (progn
                  (beginning-of-line)
                  (texinfo-copy-node-name))
              " "))
          ", (dir), (dir)"))

(defun texinfo-check-for-node-name ()
  "Determine whether the node has a node name.  Prompt for one if not.
Point must be at beginning of node line.  Does not move point."
  (save-excursion
    (forward-word 1)                    ; skip over node command
    (skip-chars-forward " \t")          ; and over spaces
    (if (not (looking-at "[^,\t\n ]+")) ; regexp based on what info looks for
                                        ; alternatively, use "[a-zA-Z]+"
        (let ((node-name (read-from-minibuffer "Node name: ")))
          (insert " " node-name)))))

(defun texinfo-delete-existing-pointers ()
  "Delete `Next', `Previous', and `Up' pointers.  
Starts from the current position of the cursor, and searches forward
on the line for a comma and if one is found, deletes the rest of the
line, including the comma.  Leaves point at beginning of line."
  (if (search-forward "," (save-excursion (end-of-line) (point)) t)
      (progn
        (goto-char (1- (point)))
        (kill-line nil)))
  (beginning-of-line))

(defun texinfo-find-pointer (beginning end level direction)
  "Move point to section associated with next, previous, or up pointer.
Return type of pointer (either 'normal or 'no-pointer).

The first and second arguments bound the search for a pointer to the
beginning and end, respectively, of the enclosing higher level
section.  The third argument is a string specifying the general kind
of section such as \"chapter\ or \"section\".  When looking for the
`Next' pointer, the section found will be at the same hierarchical
level in the Texinfo file; when looking for the `Previous' pointer,
the section found will be at the same or higher hierarchical level in
the Texinfo file; when looking for the `Up' pointer, the section found
will be at some level higher in the Texinfo file.  The fourth argument
(one of 'next, 'previous, or 'up) specifies whether to find the
`Next', `Previous', or `Up' pointer."

  (cond ((eq direction 'next)
         (forward-line 3)             ; skip over current node
         (if (re-search-forward
              (eval
               (cdr (assoc level texinfo-update-menu-same-level-regexps)))
              end
              t)
             'normal
           'no-pointer))
        ((eq direction 'previous)
         (if (re-search-backward
              (concat
               "\\("
               (eval
                (cdr (assoc level texinfo-update-menu-same-level-regexps)))
               "\\|"
               (eval
                (cdr (assoc level texinfo-update-menu-higher-regexps)))
               "\\)")
              beginning
              t)
             'normal
           'no-pointer))
        ((eq direction 'up)
         (if (re-search-backward
             (eval (cdr (assoc level texinfo-update-menu-higher-regexps)))
              beginning
              t)
             'normal
           'no-pointer))
        (t
         (error "texinfo-find-pointer: lack proper arguments"))))

(defun texinfo-pointer-name (kind)
  "Return the node name preceding the section command.
The argument is the kind of section, either normal or no-pointer."
  (let (name)
    (cond ((eq kind 'normal)
           (end-of-line)                ; this handles prev node top case
           (re-search-backward          ; when point is already 
            "^@node"                    ; at the beginning of @node line
            (save-excursion (forward-line -3))
            t)
           (setq name (texinfo-copy-node-name)))
	  ((eq kind 'no-pointer)
	   (setq name " ")))	; put a blank in the pointer slot
    name))

(defun texinfo-insert-pointer (beginning end level direction)
  "Insert the `Next', `Previous' or `Up' node name at point.
Move point forward.  

The first and second arguments bound the search for a pointer to the
beginning and end, respectively, of the enclosing higher level
section.  The third argument is the hierarchical level of the Texinfo
file, a string such as \"section\".  The fourth argument is direction
towards which the pointer is directed, one of `next, `previous, or
'up."

  (end-of-line)
  (insert
   ", "
   (save-excursion
     (texinfo-pointer-name
      (texinfo-find-pointer beginning end level direction)))))

(defun texinfo-clean-up-node-line ()
  "Remove extra commas, if any, at end of node line."
  (end-of-line)
  (skip-chars-backward ", ")
  (delete-region (point) (save-excursion (end-of-line) (point))))


;;;; Updating nodes sequentially
; These sequential update functions insert `Next' or `Previous'
; pointers that point to the following or preceding nodes even if they
; are at higher or lower hierarchical levels.  This means that if a
; section contains one or more subsections, the section's `Next'
; pointer will point to the subsection and not the following section.
; (The subsection to which `Next' points will most likely be the first
; item on the section's menu.)

(defun texinfo-sequential-node-update (&optional region-p)
  "Update one node (or many) in a Texinfo file with sequential pointers.

This function causes the `Next' or `Previous' pointer to point to the
immediately preceding or following node, even if it is at a higher or
lower hierarchical level in the document.  Continually pressing `n' or
`p' takes you straight through the file.

Without any prefix argument, update the node in which point is located.
Non-nil argument (prefix, if interactive) means update the nodes in the
marked region.

This command makes it awkward to navigate among sections and
subsections; it should be used only for those documents that are meant
to be read like a novel rather than a reference, and for which the
Info `g*' command is inadequate."
  
  (interactive "P")
  (if (not region-p)
      (let ((auto-fill-hook nil))   ; update a single node
        (if (not (re-search-backward "^@node" (point-min) t))
            (error "Node line not found before this position."))
        (texinfo-sequentially-update-the-node)
        (message 
         "Done...sequentially updated the node .  You may save the buffer."))
    ;; else
    (let ((auto-fill-hook nil)
          (beginning (region-beginning))
          (end (region-end)))
      (if (= end beginning)
          (error "Please mark a region!"))
      (save-restriction
        (narrow-to-region beginning end)
        (goto-char beginning)
        (push-mark)
        (while (re-search-forward "^@node" (point-max) t)
          (beginning-of-line)            
          (texinfo-sequentially-update-the-node))
        (message 
         "Done...updated the nodes in sequence.  You may save the buffer.")))))

(defun texinfo-sequentially-update-the-node ()
  "Update one node such that the pointers are sequential. 
A `Next' or `Previous' pointer points to any preceding or following node,
regardless of its hierarchical level."

        (texinfo-check-for-node-name)
        (texinfo-delete-existing-pointers)
        (message 
         "Sequentially updating node: %s ... " (texinfo-copy-node-name))
        (save-restriction
          (widen)
          (let*
              ((case-fold-search t)
               (level (texinfo-hierarchic-level)))
            (if (string-equal level "top")
                (texinfo-top-pointer-case)
              ;; else
              (texinfo-sequentially-insert-pointer level 'next)
              (texinfo-sequentially-insert-pointer level 'previous)
              (texinfo-sequentially-insert-pointer level 'up)
              (texinfo-clean-up-node-line)))))

(defun texinfo-sequentially-find-pointer (level direction)
  "Find next or previous pointer sequentially in Texinfo file, or up pointer.
Move point to section associated with the pointer.  Find point even if
it is in a different section.

Return type of pointer (either 'normal or 'no-pointer).

The first argument is a string specifying the general kind of section
such as \"chapter\ or \"section\".  The section found will be at the
same hierarchical level in the Texinfo file, or, in the case of the up
pointer, some level higher.  The second argument (one of 'next,
'previous, or 'up) specifies whether to find the `Next', `Previous',
or `Up' pointer."
  
  (cond ((eq direction 'next)
         (forward-line 3)             ; skip over current node
         (if (re-search-forward 
              texinfo-section-types-regexp
              (point-max)
              t)
             'normal
           'no-pointer))
        ((eq direction 'previous)
         (if (re-search-backward 
              texinfo-section-types-regexp
              (point-min)
              t)
             'normal
           'no-pointer))
        ((eq direction 'up)
         (if (re-search-backward
              (eval (cdr (assoc level texinfo-update-menu-higher-regexps)))
              beginning
              t)
             'normal
           'no-pointer))
        (t
         (error "texinfo-sequential-find-pointer: lack proper arguments"))))

(defun texinfo-sequentially-insert-pointer (level direction)
  "Insert the `Next', `Previous' or `Up' node name at point.
Move point forward.  

The first argument is the hierarchical level of the Texinfo file, a
string such as \"section\".  The second argument is direction, one of
`next, `previous, or 'up."

  (end-of-line)
  (insert
   ", "
   (save-excursion
     (texinfo-pointer-name
      (texinfo-sequentially-find-pointer level direction)))))


;;;; Inserting `@node' lines
; The `texinfo-insert-node-lines' function inserts `@node' lines as needed
; before the `@chapter', `@section', and such like lines of a region
; in a Texinfo file.

(defun texinfo-insert-node-lines (&optional title-p)
  "Insert missing `@node' lines in region of Texinfo file.
Non-nil argument (prefix, if interactive) means also to insert the
section titles as node names; and also to insert the section titles as
node names in pre-existing @node lines that lack names."
  (interactive "P")
  (save-excursion
    (let ((begin-region  (region-beginning))
          (end-region (region-end)))
      (goto-char begin-region)
      (while (< (point) end-region)
        (re-search-forward texinfo-section-types-regexp nil 'end)
        ;; copy title, since most often, we will need it
        (let ((title
               (progn
                 (beginning-of-line)
                 (forward-word 1)
                 (skip-chars-forward " \t")
                 (buffer-substring
                  (point)
                  (save-excursion (end-of-line) (point))))))
          ;; insert a node if necessary
          (if (re-search-backward
               "^@node"
               (save-excursion
                 (forward-line -3)
                 (point))
               t)
              ;;  @node present, and point at beginning of that line
              (forward-word 1)
            ;; else @node missing, insert one
            (progn
              (beginning-of-line)       ; beginning of `@section' line
              (insert "@node\n")
              (backward-char 1)))       ; leave point just after `@node'
          ;; insert a title if warranted
          (if title-p
              (progn
                (skip-chars-forward " \t")
                ;; use regexp based on what info looks for
                ;; (alternatively, use "[a-zA-Z]+")
                (if (not (looking-at "[^,\t\n ]+")) 
                    (progn
                      (beginning-of-line) 
                      (forward-word 1)
                      (insert " " title)
                      (message "Inserted title %s ... " title)))))
          ;; in any case, go forward beyond current section title
          (forward-line 3)))))
  (if title-p
      (message
       "Done inserting node lines and titles.  You may save the buffer.")
    (message "Done inserting node lines.  You may save the buffer.")))

;;;;;;;;;;;;;;;; end texnfo-upd.el ;;;;;;;;;;;;;;;;