Reconstructed and backdated initial commit of todos.el.

* calendar/todos.el: New file.  This is a copy of todo-mode.el
from 2009-01-30T13:06:07Z!lekktu@gmail.com except for the following changes: replace all
occurrences of the namespace prefix "todo-" with "todos-", delete
the defvar todo-cats (the old name of todo-categories) and its use
in todos-add-category, delete all defaliases of old command names.

2 files changed, 970 insertions, 0 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index cdc021d192f..96d79e8c15f 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,11 @@
+2012-09-11  Stephen Berman  <stephen.berman@gmx.net>
+
+        * calendar/todos.el: New file.  This is a copy of todo-mode.el
+        from revision 94343 except for the following changes: replace all
+        occurrences of the namespace prefix "todo-" with "todos-", delete
+        the defvar todo-cats (the old name of todo-categories) and its use
+        in todos-add-category, delete all defaliases of old command names.
+
 2012-09-11  Bastien Guerry  <bzg@gnu.org>
 
         * subr.el (set-temporary-overlay-map): Add a docstring.
diff --git a/lisp/calendar/todos.el b/lisp/calendar/todos.el
new file mode 100644
index 00000000000..883f2081b3e
--- /dev/null
+++ b/lisp/calendar/todos.el
@@ -0,0 +1,962 @@
+;;; todos.el --- major mode for editing TODO list files
+
+;; Copyright (C) 1997, 1999, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
+;;   2008, 2009  Free Software Foundation, Inc.
+
+;; Author: Oliver Seidel <privat@os10000.net>
+;; Maintainer: Stephen Berman <stephen.berman@gmx.net>
+;; Created: 2 Aug 1997
+;; Keywords: calendar, todo
+
+;; 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 3 of the License, 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.  If not, see <http://www.gnu.org/licenses/>.
+
+;; ---------------------------------------------------------------------------
+
+;;; Commentary:
+
+;;  Mode Description
+;;
+;;      TODO is a major mode for EMACS which offers functionality to
+;;      treat most lines in one buffer as a list of items one has to
+;;      do.  There are facilities to add new items, which are
+;;      categorised, to edit or even delete items from the buffer.
+;;      The buffer contents are currently compatible with the diary,
+;;      so that the list of todos-items will show up in the FANCY diary
+;;      mode.
+;;
+;;      Notice: Besides the major mode, this file also exports the
+;;      function `todos-show' which will change to the one specific
+;;      TODO file that has been specified in the todos-file-do
+;;      variable.  If this file does not conform to the TODO mode
+;;      conventions, the todos-show function will add the appropriate
+;;      header and footer.  I don't anticipate this to cause much
+;;      grief, but be warned, in case you attempt to read a plain text
+;;      file.
+;;
+;;  Preface, Quickstart Installation
+;;
+;;      To get this to work, make emacs execute the line
+;;
+;;          (autoload 'todos "todos"
+;;                    "Major mode for editing TODO lists." t)
+;;          (autoload 'todos-show "todos"
+;;                    "Show TODO items." t)
+;;          (autoload 'todos-insert-item "todos"
+;;                    "Add TODO item." t)
+;;
+;;      You may now enter new items by typing "M-x todos-insert-item",
+;;      or enter your TODO list file by typing "M-x todos-show".
+;;
+;;      The TODO list file has a special format and some auxiliary
+;;      information, which will be added by the todos-show function if
+;;      it attempts to visit an un-initialised file.  Hence it is
+;;      recommended to use the todos-show function for the first time,
+;;      in order to initialise the file, but it is not necessary
+;;      afterwards.
+;;
+;;      As these commands are quite long to type, I would recommend
+;;      the addition of two bindings to your to your global keymap.  I
+;;      personally have the following in my initialisation file:
+;;
+;;          (global-set-key "\C-ct" 'todos-show)  ; switch to TODO buffer
+;;          (global-set-key "\C-ci" 'todos-insert-item) ; insert new item
+;;
+;;      Note, however, that this recommendation has prompted some
+;;      criticism, since the keys C-c LETTER are reserved for user
+;;      functions.  I believe my recommendation is acceptable, since
+;;      the Emacs Lisp Manual *Tips* section also details that the
+;;      mode itself should not bind any functions to those keys.  The
+;;      express aim of the above two bindings is to work outside the
+;;      mode, which doesn't need the show function and offers a
+;;      different binding for the insert function.  They serve as
+;;      shortcuts and are not even needed (since the TODO mode will be
+;;      entered by visiting the TODO file, and later by switching to
+;;      its buffer).
+;;
+;;      If you are an advanced user of this package, please consult
+;;      the whole source code for autoloads, because there are several
+;;      extensions that are not explicitly listed in the above quick
+;;      installation.
+;;
+;;  Pre-Requisites
+;;
+;;      This package will require the following packages to be
+;;      available on the load-path:
+;;
+;;          time-stamp
+;;          easymenu
+;;
+;;  Operation
+;;
+;;      You will have the following facilities available:
+;;
+;;          M-x todos-show   will enter the todo list screen, here type
+;;
+;;          +  to go to next category
+;;          -  to go to previous category
+;;          d  to file the current entry, including a
+;;                                  comment and timestamp
+;;          e  to edit the current entry
+;;          E  to edit a multi-line entry
+;;          f  to file the current entry, including a
+;;                                  comment and timestamp
+;;          i  to insert a new entry, with prefix, omit category
+;;          I  to insert a new entry at current cursor position
+;;          j  jump to category
+;;          k  to kill the current entry
+;;          l  to lower the current entry's priority
+;;          n  for the next entry
+;;          p  for the previous entry
+;;          P  print
+;;          q  to save the list and exit the buffer
+;;          r  to raise the current entry's priority
+;;          s  to save the list
+;;          S  to save the list of top priorities
+;;          t  show top priority items for each category
+;;
+;;      When you add a new entry, you are asked for the text and then
+;;      for the category.  I for example have categories for things
+;;      that I want to do in the office (like mail my mum), that I
+;;      want to do in town (like buy cornflakes) and things I want to
+;;      do at home (move my suitcases).  The categories can be
+;;      selected with the cursor keys and if you type in the name of a
+;;      category which didn't exist before, an empty category of the
+;;      desired name will be added and filled with the new entry.
+;;
+;;  Configuration
+;;
+;;  Variable todos-prefix
+;;
+;;      I would like to recommend that you use the prefix "*/*" (by
+;;      leaving the variable 'todos-prefix' untouched) so that the
+;;      diary displays each entry every day.
+;;
+;;      To understand what I mean, please read the documentation that
+;;      goes with the calendar since that will tell you how you can
+;;      set up the fancy diary display and use the #include command to
+;;      include your todo list file as part of your diary.
+;;
+;;      If you have the diary package set up to usually display more
+;;      than one day's entries at once, consider using
+;;
+;;          "&%%(equal (calendar-current-date) date)"
+;;
+;;      as the value of `todos-prefix'.  Please note that this may slow
+;;      down the processing of your diary file some.
+;;
+;;      Carsten Dominik <dominik@strw.LeidenUniv.nl> suggested that
+;;
+;;          "&%%(todos-cp)"
+;;
+;;      might be nicer and to that effect a function has been declared
+;;      further down in the code.  You may wish to auto-load this.
+;;
+;;      Carsten also writes that that *changing* the prefix after the
+;;      todo list is already established is not as simple as changing
+;;      the variable - the todo files have to be changed by hand.
+;;
+;;  Variable todos-file-do
+;;
+;;      This variable is fairly self-explanatory.  You have to store
+;;      your TODO list somewhere.  This variable tells the package
+;;      where to go and find this file.
+;;
+;;  Variable todos-file-done
+;;
+;;      Even when you're done, you may wish to retain the entries.
+;;      Given that they're timestamped and you are offered to add a
+;;      comment, this can make a useful diary of past events.  It will
+;;      even blend in with the EMACS diary package.  So anyway, this
+;;      variable holds the name of the file for the filed todos-items.
+;;
+;;  Variable todos-file-top
+;;
+;;      File storing the top priorities of your TODO list when
+;;      todos-save-top-priorities is non-nil.  Nice to include in your
+;;      diary instead of the complete TODO list.
+;;
+;;  Variable todos-mode-hook
+;;
+;;      Just like other modes, too, this mode offers to call your
+;;      functions before it goes about its business.  This variable
+;;      will be inspected for any functions you may wish to have
+;;      called once the other TODO mode preparations have been
+;;      completed.
+;;
+;;  Variable todos-insert-threshold
+;;
+;;      Another nifty feature is the insertion accuracy.  If you have
+;;      8 items in your TODO list, then you may get asked 4 questions
+;;      by the binary insertion algorithm.  However, you may not
+;;      really have a need for such accurate priorities amongst your
+;;      TODO items.  If you now think about the binary insertion
+;;      halving the size of the window each time, then the threshold
+;;      is the window size at which it will stop.  If you set the
+;;      threshold to zero, the upper and lower bound will coincide at
+;;      the end of the loop and you will insert your item just before
+;;      that point.  If you set the threshold to, e.g. 8, it will stop
+;;      as soon as the window size drops below that amount and will
+;;      insert the item in the approximate center of that window.  I
+;;      got the idea for this feature after reading a very helpful
+;;      e-mail reply from Trey Jackson <trey@cs.berkeley.edu> who
+;;      corrected some of my awful coding and pointed me towards some
+;;      good reading.  Thanks Trey!
+;;
+;;  Things to do
+;;
+;;      These originally were my ideas, but now also include all the
+;;      suggestions that I included before forgetting them:
+;;
+;;      o   Fancy fonts for todo/top-priority buffer
+;;      o   Remove todos-prefix option in todos-top-priorities
+;;      o   Rename category
+;;      o   Move entry from one category to another one
+;;      o   Entries which both have the generic */* prefix and a
+;;          "deadline" entry which are understood by diary, indicating
+;;          an event (unless marked by &)
+;;      o   The optional COUNT variable of todos-forward-item should be
+;;          applied to the other functions performing similar tasks
+;;      o   Modularization could be done for repeated elements of
+;;          the code, like the completing-read lines of code.
+;;      o   license / version function
+;;      o   export to diary file
+;;      o   todos-report-bug
+;;      o   GNATS support
+;;      o   elide multiline (as in bbdb, or, to a lesser degree, in
+;;          outline mode)
+;;      o   rewrite complete package to store data as lisp objects
+;;          and have display modes for display, for diary export,
+;;          etc.  (Richard Stallman pointed out this is a bad idea)
+;;      o   so base todos.el on generic-mode.el instead
+;;
+;;  History and Gossip
+;;
+;;      Many thanks to all the ones who have contributed to the
+;;      evolution of this package!  I hope I have listed all of you
+;;      somewhere in the documentation or at least in the RCS history!
+;;
+;;      Enjoy this package and express your gratitude by sending nice
+;;      things to my parents' address!
+;;
+;;      Oliver Seidel
+;;      (Lessingstr.  8, 65760 Eschborn, Federal Republic of Germany)
+
+;;; Code:
+
+(require 'time-stamp)
+
+
+;; User-configurable variables:
+
+(defgroup todos nil
+  "Maintain a list of todo items."
+  :link '(emacs-commentary-link "todos")
+  :version "21.1"
+  :group 'calendar)
+
+(defcustom todos-prefix     "*/*"
+  "TODO mode prefix for entries.
+
+This is useful in conjunction with `calendar' and `diary' if you use
+
+#include \"~/.todos-do\"
+
+in your diary file to include your todo list file as part of your
+diary.  With the default value \"*/*\" the diary displays each entry
+every day and it may also be marked on every day of the calendar.
+Using \"&%%(equal (calendar-current-date) date)\" instead will only
+show and mark todo entries for today, but may slow down processing of
+the diary file somewhat."
+  :type 'string
+  :group 'todos)
+(defcustom todos-file-do    (convert-standard-filename "~/.todos-do")
+  "TODO mode list file."
+  :type 'file
+  :group 'todos)
+(defcustom todos-file-done  (convert-standard-filename "~/.todos-done")
+  "TODO mode archive file."
+  :type 'file
+  :group 'todos)
+(defcustom todos-mode-hook  nil
+  "TODO mode hooks."
+  :type 'hook
+  :group 'todos)
+(defcustom todos-edit-mode-hook nil
+  "TODO Edit mode hooks."
+  :type 'hook
+  :group 'todos)
+(defcustom todos-insert-threshold 0
+  "TODO mode insertion accuracy.
+
+If you have 8 items in your TODO list, then you may get asked 4
+questions by the binary insertion algorithm.  However, you may not
+really have a need for such accurate priorities amongst your TODO
+items.  If you now think about the binary insertion halving the size
+of the window each time, then the threshold is the window size at
+which it will stop.  If you set the threshold to zero, the upper and
+lower bound will coincide at the end of the loop and you will insert
+your item just before that point.  If you set the threshold to,
+e.g. 8, it will stop as soon as the window size drops below that
+amount and will insert the item in the approximate center of that
+window."
+  :type 'integer
+  :group 'todos)
+(defvar todos-edit-buffer " *TODO Edit*"
+  "TODO Edit buffer name.")
+(defcustom todos-file-top (convert-standard-filename "~/.todos-top")
+  "TODO mode top priorities file.
+
+Not in TODO format, but diary compatible.
+Automatically generated when `todos-save-top-priorities' is non-nil."
+  :type 'string
+  :group 'todos)
+
+(defcustom todos-print-function 'ps-print-buffer-with-faces
+  "Function to print the current buffer."
+  :type 'symbol
+  :group 'todos)
+(defcustom todos-show-priorities 1
+  "Default number of priorities to show by \\[todos-top-priorities].
+0 means show all entries."
+  :type 'integer
+  :group 'todos)
+(defcustom todos-print-priorities 0
+  "Default number of priorities to print by \\[todos-print].
+0 means print all entries."
+  :type 'integer
+  :group 'todos)
+(defcustom todos-remove-separator t
+  "Non-nil to remove category separators in\
+\\[todos-top-priorities] and \\[todos-print]."
+  :type 'boolean
+  :group 'todos)
+(defcustom todos-save-top-priorities-too t
+  "Non-nil makes `todos-save' automatically save top-priorities in `todos-file-top'."
+  :type 'boolean
+  :group 'todos)
+
+;; Thanks for the ISO time stamp format go to Karl Eichwalder <ke@suse.de>
+;; My format string for the appt.el package is "%3b %2d, %y, %02I:%02M%p".
+;;
+(defcustom todos-time-string-format
+  "%:y-%02m-%02d %02H:%02M"
+  "TODO mode time string format for done entries.
+For details see the variable `time-stamp-format'."
+  :type 'string
+  :group 'todos)
+
+(defcustom todos-entry-prefix-function 'todos-entry-timestamp-initials
+  "Function producing text to insert at start of todo entry."
+  :type 'symbol
+  :group 'todos)
+(defcustom todos-initials (or (getenv "INITIALS") (user-login-name))
+  "Initials of todo item author."
+  :type 'string
+  :group 'todos)
+
+(defun todos-entry-timestamp-initials ()
+  "Prepend timestamp and your initials to the head of a TODO entry."
+  (let ((time-stamp-format todos-time-string-format))
+    (concat (time-stamp-string) " " todos-initials ": ")))
+
+;; ---------------------------------------------------------------------------
+
+;; Set up some helpful context ...
+
+(defvar todos-categories nil
+  "TODO categories.")
+
+(defvar todos-previous-line 0
+  "Previous line asked about.")
+
+(defvar todos-previous-answer 0
+  "Previous answer got.")
+
+(defvar todos-mode-map
+  (let ((map (make-keymap)))
+    (suppress-keymap map t)
+    (define-key map "+" 'todos-forward-category)
+    (define-key map "-" 'todos-backward-category)
+    (define-key map "d" 'todos-file-item) ;done/delete
+    (define-key map "e" 'todos-edit-item)
+    (define-key map "E" 'todos-edit-multiline)
+    (define-key map "f" 'todos-file-item)
+    (define-key map "i" 'todos-insert-item)
+    (define-key map "I" 'todos-insert-item-here)
+    (define-key map "j" 'todos-jump-to-category)
+    (define-key map "k" 'todos-delete-item)
+    (define-key map "l" 'todos-lower-item)
+    (define-key map "n" 'todos-forward-item)
+    (define-key map "p" 'todos-backward-item)
+    (define-key map "P" 'todos-print)
+    (define-key map "q" 'todos-quit)
+    (define-key map "r" 'todos-raise-item)
+    (define-key map "s" 'todos-save)
+    (define-key map "S" 'todos-save-top-priorities)
+    (define-key map "t" 'todos-top-priorities)
+    map)
+  "TODO mode keymap.")
+
+(defvar todos-category-number 0 "TODO category number.")
+
+(defvar todos-tmp-buffer-name " *todo tmp*")
+
+(defvar todos-category-sep (make-string 75 ?-)
+  "Category separator.")
+
+(defvar todos-category-beg " --- "
+  "Category start separator to be prepended onto category name.")
+
+(defvar todos-category-end "--- End"
+  "Separator after a category.")
+
+(defvar todos-header "-*- mode: todo; "
+  "Header of todo files.")
+
+;; ---------------------------------------------------------------------------
+
+(defun todos-category-select ()
+  "Make TODO mode display the current category correctly."
+  (let ((name (nth todos-category-number todos-categories)))
+    (setq mode-line-buffer-identification
+;;          (concat "Category: " name))
+          (concat "Category: " (format "%18s" name)))
+    (widen)
+    (goto-char (point-min))
+    (search-forward-regexp
+     (concat "^"
+             (regexp-quote (concat todos-prefix todos-category-beg name))
+             "$"))
+    (let ((begin (1+ (line-end-position))))
+      (search-forward-regexp (concat "^" todos-category-end))
+      (narrow-to-region begin (line-beginning-position))
+      (goto-char (point-min)))))
+
+(defun todos-forward-category ()
+  "Go forward to TODO list of next category."
+  (interactive)
+  (setq todos-category-number
+        (mod (1+ todos-category-number) (length todos-categories)))
+  (todos-category-select))
+
+(defun todos-backward-category ()
+  "Go back to TODO list of previous category."
+  (interactive)
+  (setq todos-category-number
+        (mod (1- todos-category-number) (length todos-categories)))
+  (todos-category-select))
+
+(defun todos-backward-item ()
+  "Select previous entry of TODO list."
+  (interactive)
+  (search-backward-regexp (concat "^" (regexp-quote todos-prefix)) nil t)
+  (message ""))
+
+(defun todos-forward-item (&optional count)
+  "Select COUNT-th next entry of TODO list."
+  (interactive "P")
+  (if (listp count) (setq count (car count)))
+  (end-of-line)
+  (search-forward-regexp (concat "^" (regexp-quote todos-prefix))
+                         nil 'goto-end count)
+  (beginning-of-line)
+  (message ""))
+
+(defun todos-save ()
+  "Save the TODO list."
+  (interactive)
+  (save-excursion
+    (save-restriction
+      (save-buffer)))
+  (if todos-save-top-priorities-too (todos-save-top-priorities)))
+
+(defun todos-quit ()
+  "Done with TODO list for now."
+  (interactive)
+  (widen)
+  (todos-save)
+  (message "")
+  (bury-buffer))
+
+(defun todos-edit-item ()
+  "Edit current TODO list entry."
+  (interactive)
+  (let ((item (todos-item-string)))
+    (if (todos-string-multiline-p item)
+        (todos-edit-multiline)
+      (let ((new (read-from-minibuffer "Edit: " item)))
+        (todos-remove-item)
+        (insert new "\n")
+        (todos-backward-item)
+        (message "")))))
+
+(defun todos-edit-multiline ()
+  "Set up a buffer for editing a multiline TODO list entry."
+  (interactive)
+  (let ((buffer-name (generate-new-buffer-name todos-edit-buffer)))
+    (switch-to-buffer
+     (make-indirect-buffer
+      (file-name-nondirectory todos-file-do) buffer-name))
+    (message "To exit, simply kill this buffer and return to list.")
+    (todos-edit-mode)
+    (narrow-to-region (todos-item-start) (todos-item-end))))
+
+;;;###autoload
+(defun todos-add-category (&optional cat)
+  "Add new category CAT to the TODO list."
+  (interactive)
+  (let ((buf (find-file-noselect todos-file-do t))
+        (prompt "Category: "))
+    (unless (zerop (buffer-size buf))
+      (and (null todos-categories)
+           (error "Error in %s: File is non-empty but contains no category" 
+                  todos-file-do)))
+    (unless cat (setq cat (read-from-minibuffer prompt)))
+    (with-current-buffer buf
+      ;; reject names that could induce bugs and confusion
+      (while (and (cond ((string= "" cat)
+                         (setq prompt "Enter a non-empty category name: "))
+                        ((string-match "\\`\\s-+\\'" cat)
+                         (setq prompt "Enter a category name that is not only white space: "))
+                        ((member cat todos-categories)
+                         (setq prompt "Enter a non-existing category name: ")))
+                  (setq cat (read-from-minibuffer prompt))))
+      ;; initialize a newly created Todo buffer for Todo mode
+      (unless (file-exists-p todos-file-do) (todos-mode))
+      (setq todos-categories (cons cat todos-categories))
+      (widen)
+      (goto-char (point-min))
+      (if (search-forward "-*- mode: todo; " 17 t)
+          (kill-line)
+        (insert "-*- mode: todo; \n")
+        (forward-char -1))
+      (insert (format "todos-categories: %S; -*-" todos-categories))
+      (forward-char 1)
+      (insert (format "%s%s%s\n%s\n%s %s\n"
+                      todos-prefix todos-category-beg cat
+                      todos-category-end
+                      todos-prefix todos-category-sep))
+      (if (interactive-p)
+          ;; properly display the newly added category
+          (progn (setq todos-category-number 0) (todos-show))
+        0))))
+
+;;;###autoload
+(defun todos-add-item-non-interactively (new-item category)
+  "Insert NEW-ITEM in TODO list as a new entry in CATEGORY."
+  (save-excursion
+    (todos-show))
+  (save-excursion
+    (if (string= "" category)
+        (setq category (nth todos-category-number todos-categories)))
+    (let ((cat-exists (member category todos-categories)))
+      (setq todos-category-number
+            (if cat-exists
+                (- (length todos-categories) (length cat-exists))
+              (todos-add-category category))))
+    (todos-show)
+    (setq todos-previous-line 0)
+    (let ((top 1)
+          (bottom (1+ (count-lines (point-min) (point-max)))))
+      (while (> (- bottom top) todos-insert-threshold)
+        (let* ((current (/ (+ top bottom) 2))
+               (answer (if (< current bottom)
+                           (todos-more-important-p current) nil)))
+          (if answer
+              (setq bottom current)
+            (setq top (1+ current)))))
+      (setq top (/ (+ top bottom) 2))
+      ;; goto-line doesn't have the desired behavior in a narrowed buffer.
+      (goto-char (point-min))
+      (forward-line (1- top)))
+    (insert new-item "\n")
+    (todos-backward-item)
+    (todos-save)
+    (message "")))
+
+;;;###autoload
+(defun todos-insert-item (arg)
+  "Insert new TODO list entry.
+With a prefix argument solicit the category, otherwise use the current
+category."
+  (interactive "P")
+  (save-excursion
+    (if (not (derived-mode-p 'todos-mode)) (todos-show))
+    (let* ((new-item (concat todos-prefix " "
+                             (read-from-minibuffer
+                              "New TODO entry: "
+                              (if todos-entry-prefix-function
+                                  (funcall todos-entry-prefix-function)))))
+           (current-category (nth todos-category-number todos-categories))
+           (category (if arg (todos-completing-read) current-category)))
+      (todos-add-item-non-interactively new-item category))))
+
+(defun todos-insert-item-here ()
+  "Insert a new TODO list entry directly above the entry at point.
+If point is on an empty line, insert the entry there."
+  (interactive)
+  (if (not (derived-mode-p 'todos-mode)) (todos-show))
+  (let ((new-item (concat todos-prefix " "
+                          (read-from-minibuffer
+                           "New TODO entry: "
+                           (if todos-entry-prefix-function
+                               (funcall todos-entry-prefix-function))))))
+    (unless (and (bolp) (eolp)) (goto-char (todos-item-start)))
+    (insert (concat new-item "\n"))
+    (backward-char)
+    ;; put point at start of new entry
+    (goto-char (todos-item-start))))
+
+(defun todos-more-important-p (line)
+  "Ask whether entry is more important than the one at LINE."
+  (unless (equal todos-previous-line line)
+    (setq todos-previous-line line)
+    (goto-char (point-min))
+    (forward-line (1- todos-previous-line))
+    (let ((item (todos-item-string-start)))
+      (setq todos-previous-answer
+            (y-or-n-p (concat "More important than '" item "'? ")))))
+  todos-previous-answer)
+
+(defun todos-delete-item ()
+  "Delete current TODO list entry."
+  (interactive)
+  (if (> (count-lines (point-min) (point-max)) 0)
+      (let* ((todos-entry (todos-item-string-start))
+             (todos-answer (y-or-n-p (concat "Permanently remove '"
+                                            todos-entry "'? "))))
+        (when todos-answer
+          (todos-remove-item)
+          (todos-backward-item))
+        (message ""))
+    (error "No TODO list entry to delete")))
+
+(defun todos-raise-item ()
+  "Raise priority of current entry."
+  (interactive)
+  (if (> (count-lines (point-min) (point)) 0)
+      (let ((item (todos-item-string)))
+        (todos-remove-item)
+        (todos-backward-item)
+        (save-excursion
+          (insert item "\n"))
+        (message ""))
+    (error "No TODO list entry to raise")))
+
+(defun todos-lower-item ()
+  "Lower priority of current entry."
+  (interactive)
+  (if (> (count-lines (point) (point-max)) 1)
+      ;; Assume there is a final newline
+      (let ((item (todos-item-string)))
+        (todos-remove-item)
+        (todos-forward-item)
+        (save-excursion
+          (insert item "\n"))
+        (message ""))
+    (error "No TODO list entry to lower")))
+
+(defun todos-file-item (&optional comment)
+  "File the current TODO list entry away, annotated with an optional COMMENT."
+  (interactive "sComment: ")
+  (or (> (count-lines (point-min) (point-max)) 0)
+      (error "No TODO list entry to file away"))
+  (let ((time-stamp-format todos-time-string-format))
+    (when (and comment (> (length comment) 0))
+      (goto-char (todos-item-end))
+      (insert
+       (if (save-excursion (beginning-of-line)
+                           (looking-at (regexp-quote todos-prefix)))
+           " "
+         "\n\t")
+       "(" comment ")"))
+    (goto-char (todos-item-end))
+    (insert " [" (nth todos-category-number todos-categories) "]")
+    (goto-char (todos-item-start))
+    (let ((temp-point (point)))
+      (if (looking-at (regexp-quote todos-prefix))
+          (replace-match (time-stamp-string))
+        ;; Standard prefix -> timestamp
+        ;; Else prefix non-standard item start with timestamp
+        (insert (time-stamp-string)))
+      (append-to-file temp-point (1+ (todos-item-end)) todos-file-done)
+      (delete-region temp-point (1+ (todos-item-end))))
+    (todos-backward-item)
+    (message "")))
+
+;; ---------------------------------------------------------------------------
+
+;; Utility functions:
+
+
+;;;###autoload
+(defun todos-top-priorities (&optional nof-priorities category-pr-page)
+  "List top priorities for each category.
+
+Number of entries for each category is given by NOF-PRIORITIES which
+defaults to \'todos-show-priorities\'.
+
+If CATEGORY-PR-PAGE is non-nil, a page separator \'^L\' is inserted
+between each category."
+
+  (interactive "P")
+  (or nof-priorities (setq nof-priorities todos-show-priorities))
+  (if (listp nof-priorities)            ;universal argument
+      (setq nof-priorities (car nof-priorities)))
+  (let ((todos-print-buffer-name todos-tmp-buffer-name)
+        ;;(todos-print-category-number 0)
+        (todos-category-break (if category-pr-page "" ""))
+        (cat-end
+         (concat
+          (if todos-remove-separator
+              (concat todos-category-end "\n"
+                      (regexp-quote todos-prefix) " " todos-category-sep "\n")
+            (concat todos-category-end "\n"))))
+        beg end)
+    (todos-show)
+    (save-excursion
+      (save-restriction
+        (widen)
+        (copy-to-buffer todos-print-buffer-name (point-min) (point-max))
+        (set-buffer todos-print-buffer-name)
+        (goto-char (point-min))
+        (when (re-search-forward (regexp-quote todos-header) nil t)
+          (beginning-of-line 1)
+          (delete-region (point) (line-end-position)))
+        (while (re-search-forward       ;Find category start
+                (regexp-quote (concat todos-prefix todos-category-beg))
+                nil t)
+          (setq beg (+ (line-end-position) 1)) ;Start of first entry.
+          (re-search-forward cat-end nil t)
+          (setq end (match-beginning 0))
+          (replace-match todos-category-break)
+          (narrow-to-region beg end)    ;In case we have too few entries.
+          (goto-char (point-min))
+          (if (zerop nof-priorities)      ;Traverse entries.
+              (goto-char end)            ;All entries
+            (todos-forward-item nof-priorities))
+          (setq beg (point))
+          (delete-region beg end)
+          (widen))
+        (and (looking-at "") (replace-match "")) ;Remove trailing form-feed.
+        (goto-char (point-min))         ;Due to display buffer
+        ))
+    ;; Could have used switch-to-buffer as it has a norecord argument,
+    ;; which is nice when we are called from e.g. todos-print.
+    ;; Else we could have used pop-to-buffer.
+    (display-buffer todos-print-buffer-name)
+    (message "Type C-x 1 to remove %s window.  M-C-v to scroll the help."
+             todos-print-buffer-name)))
+
+(defun todos-save-top-priorities (&optional nof-priorities)
+  "Save top priorities for each category in `todos-file-top'.
+
+Number of entries for each category is given by NOF-PRIORITIES which
+defaults to `todos-show-priorities'."
+  (interactive "P")
+  (save-window-excursion
+    (save-excursion
+      (save-restriction
+        (todos-top-priorities nof-priorities)
+        (set-buffer todos-tmp-buffer-name)
+        (write-file todos-file-top)
+        (kill-this-buffer)))))
+
+;;;###autoload
+(defun todos-print (&optional category-pr-page)
+  "Print todo summary using `todos-print-function'.
+If CATEGORY-PR-PAGE is non-nil, a page separator `^L' is inserted
+between each category.
+
+Number of entries for each category is given by `todos-print-priorities'."
+  (interactive "P")
+  (save-window-excursion
+    (save-excursion
+      (save-restriction
+        (todos-top-priorities todos-print-priorities
+                             category-pr-page)
+        (set-buffer todos-tmp-buffer-name)
+        (and (funcall todos-print-function)
+             (kill-this-buffer))
+        (message "Todo printing done.")))))
+
+(defun todos-jump-to-category ()
+  "Jump to a category.  Default is previous category."
+  (interactive)
+  (let ((category (todos-completing-read)))
+    (if (string= "" category)
+        (setq category (nth todos-category-number todos-categories)))
+    (setq todos-category-number
+          (if (member category todos-categories)
+              (- (length todos-categories)
+                 (length (member category todos-categories)))
+            (todos-add-category category)))
+    (todos-show)))
+
+(defun todos-line-string ()
+  "Return current line in buffer as a string."
+  (buffer-substring (line-beginning-position) (line-end-position)))
+
+(defun todos-item-string-start ()
+  "Return the start of this TODO list entry as a string."
+  ;; Suitable for putting in the minibuffer when asking the user
+  (let ((item (todos-item-string)))
+    (if (> (length item) 60)
+        (setq item (concat (substring item 0 56) "...")))
+    item))
+
+(defun todos-item-start ()
+  "Return point at start of current TODO list item."
+  (save-excursion
+    (beginning-of-line)
+    (if (not (looking-at (regexp-quote todos-prefix)))
+        (search-backward-regexp
+         (concat "^" (regexp-quote todos-prefix)) nil t))
+    (point)))
+
+(defun todos-item-end ()
+  "Return point at end of current TODO list item."
+  (save-excursion
+    (end-of-line)
+    (search-forward-regexp
+     (concat "^" (regexp-quote todos-prefix)) nil 'goto-end)
+    (1- (line-beginning-position))))
+
+(defun todos-remove-item ()
+  "Delete the current entry from the TODO list."
+  (delete-region (todos-item-start) (1+ (todos-item-end))))
+
+(defun todos-item-string ()
+  "Return current TODO list entry as a string."
+  (buffer-substring (todos-item-start) (todos-item-end)))
+
+(defun todos-string-count-lines (string)
+  "Return the number of lines STRING spans."
+  (length (split-string string "\n")))
+
+(defun todos-string-multiline-p (string)
+  "Return non-nil if STRING spans several lines."
+  (> (todos-string-count-lines string) 1))
+
+(defun todos-completing-read ()
+  "Return a category name, with completion, for use in Todo mode."
+  ;; make a copy of todos-categories in case history-delete-duplicates is
+  ;; non-nil, which makes completing-read alter todos-categories
+  (let* ((categories (copy-sequence todos-categories))
+         (history (cons 'todos-categories (1+ todos-category-number)))
+         (default (nth todos-category-number todos-categories))
+         (category (completing-read
+                    (concat "Category [" default "]: ")
+                    todos-categories nil nil nil history default)))
+    ;; restore the original value of todos-categories
+    (setq todos-categories categories)
+    category))
+
+;; ---------------------------------------------------------------------------
+
+(easy-menu-define todos-menu todos-mode-map "Todo Menu"
+                  '("Todo"
+                    ["Next category"        todos-forward-category t]
+                    ["Previous category"    todos-backward-category t]
+                    ["Jump to category"     todos-jump-to-category t]
+                    ["Show top priority items" todos-top-priorities t]
+                    ["Print categories"     todos-print t]
+                    "---"
+                    ["Edit item"            todos-edit-item t]
+                    ["File item"            todos-file-item t]
+                    ["Insert new item"      todos-insert-item t]
+                    ["Insert item here"     todos-insert-item-here t]
+                    ["Kill item"            todos-delete-item t]
+                    "---"
+                    ["Lower item priority"  todos-lower-item t]
+                    ["Raise item priority"  todos-raise-item t]
+                    "---"
+                    ["Next item"            todos-forward-item t]
+                    ["Previous item"        todos-backward-item t]
+                    "---"
+                    ["Save"                 todos-save t]
+                    ["Save Top Priorities"  todos-save-top-priorities t]
+                    "---"
+                    ["Quit"                 todos-quit t]
+                    ))
+
+;; As calendar reads .todos-do before todos-mode is loaded.
+;;;###autoload
+(defun todos-mode ()
+  "Major mode for editing TODO lists.
+
+\\{todos-mode-map}"
+  (interactive)
+  (kill-all-local-variables)
+  (setq major-mode 'todos-mode)
+  (setq mode-name "TODO")
+  (use-local-map todos-mode-map)
+  (easy-menu-add todos-menu)
+  (run-mode-hooks 'todos-mode-hook))
+
+(defvar date)
+(defvar entry)
+
+;; t-c should be used from diary code, which requires calendar.
+(declare-function calendar-current-date "calendar" nil)
+
+;; Read about this function in the setup instructions above!
+;;;###autoload
+(defun todos-cp ()
+  "Make a diary entry appear only in the current date's diary."
+  (if (equal (calendar-current-date) date)
+      entry))
+
+(define-derived-mode todos-edit-mode text-mode "TODO Edit"
+  "Major mode for editing items in the TODO list.
+
+\\{todos-edit-mode-map}")
+
+;;;###autoload
+(defun todos-show ()
+  "Show TODO list."
+  (interactive)
+  ;; Call todos-initial-setup only if there is neither a Todo file nor
+  ;; a corresponding unsaved buffer.
+  (if (or (file-exists-p todos-file-do)
+          (let* ((buf (get-buffer (file-name-nondirectory todos-file-do)))
+                 (bufname (buffer-file-name buf)))
+            (equal (expand-file-name todos-file-do) bufname)))
+      (find-file todos-file-do)
+    (todos-initial-setup))
+  (if (null todos-categories)
+      (if (null todos-cats)
+          (error "Error in %s: No categories in list `todos-categories'"
+                 todos-file-do)
+        (goto-char (point-min))
+        (and (search-forward "todos-cats:" nil t)
+             (replace-match "todos-categories:"))
+        (make-local-variable 'todos-categories)
+        (setq todos-categories todos-cats)))
+  (beginning-of-line)
+  (todos-category-select))
+
+(defun todos-initial-setup ()
+  "Set up things to work properly in TODO mode."
+  (find-file todos-file-do)
+  (erase-buffer)
+  (todos-mode)
+  (todos-add-category "Todos"))
+
+(provide 'todos)
+
+;; arch-tag: 6fd91be5-776e-4464-a109-da4ea0e4e497
+;;; todos.el ends here