* calendar/todos.el Add and revise further doc strings and

comments; major code rearrangement.
(todos-merged-files, todos-prompt-merged-files)
(todos-print-priorities, todos-tmp-buffer-name)
(todos-top-priorities-widgets, todos-update-merged-files)
(todos-merged-top-priorities, todos-merged-diary-items)
(todos-merged-regexp-items, todos-merged-custom-items)
(todos-raw-mode, todos-change-default-file)
(todos-toggle-diary-inclusion, todos-toggle-item-diary-nonmarking)
(todos-toggle-diary-nonmarking, todos-validate-category-name):
Remove.
(todos-category-string-matcher): Comment out.
(todos-categories): New defgroup.
(todos-initial-file, todos-filter-buffer)
(todos-top-priorities-buffer, todos-categories-category-label)
(todos-diary-items-buffer, todos-regexp-items-buffer)
(todos-custom-items-buffer, todos-filter-files)
(todos-highlight-item, todos-todo-mode-date-time-regexp):
New defcustoms.
(todos-diary-expired): New face.
(todos-print-buffer, todos-multiple-files)
(todos-multiple-files-widget, todos-key-bindings): New variables.
(todos-short-file-name, todos-reevaluate-default-file-defcustom)
(todos-special-buffer-name)
(todos-reevaluate-filter-files-defcustom)
(todos-reset-highlight-item, todos-reevaluate-defcustoms)
(todos-nondiary-marker-matcher, todos-diary-nonmarking-matcher)
(todos-diary-expired-matcher, todos-category-string-matcher-1)
(todos-category-string-matcher-2, todos-repair-categories-sexp)
(todos-validate-name, todos-multiple-files)
(todos-display-categories-1, todos-update-categories-display)
(todos-modes-set-3, todos-mode-external-set): New functions.
(todos-set-top-priorities-in-file)
(todos-set-top-priorities-in-category)
(todos-top-priorities-multifile, todos-diary-items-multifile)
(todos-regexp-items-multifile, todos-custom-items-multifile)
(todos-convert-legacy-files, todos-jump-to-item)
(todos-edit-multiline-item, todos-edit-item-date-from-calendar)
(todos-edit-item-diary-inclusion)
(todos-edit-category-diary-inclusion)
(todos-edit-item-diary-nonmarking)
(todos-edit-category-diary-nonmarking): New commands.
(todos, todos-faces): Update :version.
(todos-done-separator, todos-completion-ignore-case):
Change default value.
(todos-done-separator): Change :set function.
(todos-indent-to-here): Add :validate function to :type.
(todos-prefix-string, todos-mark, todos-button)
(todos-sorted-column, todos-archived-only, todos-search)
(todos-done, todos-done-sep): Provide full face definitions
instead of inheriting.
(todos-edit-buffer, todos-categories-buffer): Change from
defcustom to defvar.
(todos-category-beg, todos-category-done): Change from defvar to
defconst.
(todos-files): Check if todos-files-directory exists.
(todos-default-todos-file, todos-mode-line-control, todos-print):
Use todos-short-file-name.
(todos-font-lock-keywords): Use todos-nondiary-marker-matcher,
todos-diary-nonmarking-matcher, todos-category-string-matcher-1,
todos-category-string-matcher-2, todos-diary-expired-matcher.
(todos-category-select): Use todos-done-string-start, and
condition search on todos-show-with-done; don't make display
overlay for done items separator string if there already is one;
use todos-highlight-item, require hl-line and activate
hl-line-mode here in order to avoid a hang if done in todos-mode
or the mode hook.
(todos-update-categories-sexp): Use todos-categories-full if set,
otherwise todos-categories.
(todos-make-categories-list): Don't test for archive file when
processing a legacy todo-mode file.
(todos-check-format): Add check for todos-categories sexp.
(todos-diary-item-p): Use todos-nondiary-start instead of
todos-date-pattern.
(todos-marked-item-p): Rename from todos-item-marked-p.
(todos-read-file-name): Don't accept empty name; validate.
(todos-read-category): Validate new name before prompting whether
to add new category; force quit if user answers no.
(todos-filter-items): Improve implementation.
(todos-set-top-priorities): Rewrite as a noninteractive function
using minibuffer input instead of widgets.
(todos-insert-sort-button): Call todos-display-sorted with
argument nil to display categories in numerical order, instead of
calling todos-display-categories.
(powerset-recursive): Borrow and slightly reformulate the (GDFL'd)
Common Lisp powerset function at
http://rosettacode.org/wiki/Power_set#Common_Lisp.
(powerset-bitwise): Implement in Emacs Lisp the (GDFL'd) C
powerset function at http://rosettacode.org/wiki/Power_set#C.
(todos-powerset): Defalias to powerset-bitwise.
(todos-mode-map): Generate from todos-key-bindings instead of
listing each key definition.
(todos-categories-mode-map): Add two bindings.
(todos-filter-items-mode-map): Add some bindings, remove others.
(todos-mode): Derive from special-mode; use todos-modes-set-3; add
function setting todos-done-separator to
window-configuration-change-hook.
(todos-unload-hook): Remove function setting todos-done-separator
from window-configuration-change-hook.
(todos-archive-mode): Derive from todos-mode; use todos-modes-set-3.
(todos-edit-mode): Derive from text-mode; use todos-mode-external-set.
(todos-categories-mode): Derive from special-mode; use
todos-mode-external-set.
(todos-filter-items-mode): Derive from special-mode.
(todos-quit): Save archive file if it hasn't yet been saved.
(todos-display-categories): Delegate all functionality to
todos-display-categories-1 and todos-update-categories-display.
(todos-toggle-view-done-items): Improve implementation.
(todos-highlight-item): Require hl-line.
(todos-toggle-display-date-time): Remove argument and make it
apply only to whole file.
(todos-top-priorities, todos-diary-items, todos-regexp-items)
(todos-custom-items): Use todos-special-buffer-name.
(todos-add-file): Use todos-short-file-name and
todos-reevaluate-defcustoms; remove validation, since it's now
done in todos-read-file-name.
(todos-add-category): Also update todos-categories-full if non-nil.
(todos-delete-category): Delete file after confirmation if only
category is deleted.
(todos-move-category): Use todos-short-file-name and
todos-reevaluate-defcustoms.
(todos-insert-item): Fix getting date from the calendar and
insertion of time string.
(todos-set-date-from-calendar): Enter calendar buffer, suppressing
display of diary entries.
(todos-edit-multiline): Add optional argument to restrict editing
buffer to current item, otherwise make entire buffer (i.e. whole
file) editable.
(todos-edit-quit): When whole file is editable, check file format
validity before killing buffer, and if valid, recalculate
categories sexp to be safe.
(todos-edit-item-header): Allow choosing date from calendar.
(todos-item-done): Handle marked items.

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 9fe801d..1933b7c 100644 (file)
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,139 @@
+2012-09-20  Stephen Berman  <stephen.berman@gmx.net>
+
+       * calendar/todos.el Add and revise further doc strings and
+       comments; major code rearrangement.
+       (todos-merged-files, todos-prompt-merged-files)
+       (todos-print-priorities, todos-tmp-buffer-name)
+       (todos-top-priorities-widgets, todos-update-merged-files)
+       (todos-merged-top-priorities, todos-merged-diary-items)
+       (todos-merged-regexp-items, todos-merged-custom-items)
+       (todos-raw-mode, todos-change-default-file)
+       (todos-toggle-diary-inclusion, todos-toggle-item-diary-nonmarking)
+       (todos-toggle-diary-nonmarking, todos-validate-category-name):
+       Remove.
+       (todos-category-string-matcher): Comment out.
+       (todos-categories): New defgroup.
+       (todos-initial-file, todos-filter-buffer)
+       (todos-top-priorities-buffer, todos-categories-category-label)
+       (todos-diary-items-buffer, todos-regexp-items-buffer)
+       (todos-custom-items-buffer, todos-filter-files)
+       (todos-highlight-item, todos-todo-mode-date-time-regexp):
+       New defcustoms.
+       (todos-diary-expired): New face.
+       (todos-print-buffer, todos-multiple-files)
+       (todos-multiple-files-widget, todos-key-bindings): New variables.
+       (todos-short-file-name, todos-reevaluate-default-file-defcustom)
+       (todos-special-buffer-name)
+       (todos-reevaluate-filter-files-defcustom)
+       (todos-reset-highlight-item, todos-reevaluate-defcustoms)
+       (todos-nondiary-marker-matcher, todos-diary-nonmarking-matcher)
+       (todos-diary-expired-matcher, todos-category-string-matcher-1)
+       (todos-category-string-matcher-2, todos-repair-categories-sexp)
+       (todos-validate-name, todos-multiple-files)
+       (todos-display-categories-1, todos-update-categories-display)
+       (todos-modes-set-3, todos-mode-external-set): New functions.
+       (todos-set-top-priorities-in-file)
+       (todos-set-top-priorities-in-category)
+       (todos-top-priorities-multifile, todos-diary-items-multifile)
+       (todos-regexp-items-multifile, todos-custom-items-multifile)
+       (todos-convert-legacy-files, todos-jump-to-item)
+       (todos-edit-multiline-item, todos-edit-item-date-from-calendar)
+       (todos-edit-item-diary-inclusion)
+       (todos-edit-category-diary-inclusion)
+       (todos-edit-item-diary-nonmarking)
+       (todos-edit-category-diary-nonmarking): New commands.
+       (todos, todos-faces): Update :version.
+       (todos-done-separator, todos-completion-ignore-case):
+       Change default value.
+       (todos-done-separator): Change :set function.
+       (todos-indent-to-here): Add :validate function to :type.
+       (todos-prefix-string, todos-mark, todos-button)
+       (todos-sorted-column, todos-archived-only, todos-search)
+       (todos-done, todos-done-sep): Provide full face definitions
+       instead of inheriting.
+       (todos-edit-buffer, todos-categories-buffer): Change from
+       defcustom to defvar.
+       (todos-category-beg, todos-category-done): Change from defvar to
+       defconst.
+       (todos-files): Check if todos-files-directory exists.
+       (todos-default-todos-file, todos-mode-line-control, todos-print):
+       Use todos-short-file-name.
+       (todos-font-lock-keywords): Use todos-nondiary-marker-matcher,
+       todos-diary-nonmarking-matcher, todos-category-string-matcher-1,
+       todos-category-string-matcher-2, todos-diary-expired-matcher.
+       (todos-category-select): Use todos-done-string-start, and
+       condition search on todos-show-with-done; don't make display
+       overlay for done items separator string if there already is one;
+       use todos-highlight-item, require hl-line and activate
+       hl-line-mode here in order to avoid a hang if done in todos-mode
+       or the mode hook.
+       (todos-update-categories-sexp): Use todos-categories-full if set,
+       otherwise todos-categories.
+       (todos-make-categories-list): Don't test for archive file when
+       processing a legacy todo-mode file.
+       (todos-check-format): Add check for todos-categories sexp.
+       (todos-diary-item-p): Use todos-nondiary-start instead of
+       todos-date-pattern.
+       (todos-marked-item-p): Rename from todos-item-marked-p.
+       (todos-read-file-name): Don't accept empty name; validate.
+       (todos-read-category): Validate new name before prompting whether
+       to add new category; force quit if user answers no.
+       (todos-filter-items): Improve implementation.
+       (todos-set-top-priorities): Rewrite as a noninteractive function
+       using minibuffer input instead of widgets.
+       (todos-insert-sort-button): Call todos-display-sorted with
+       argument nil to display categories in numerical order, instead of
+       calling todos-display-categories.
+       (powerset-recursive): Borrow and slightly reformulate the (GDFL'd)
+       Common Lisp powerset function at
+       http://rosettacode.org/wiki/Power_set#Common_Lisp.
+       (powerset-bitwise): Implement in Emacs Lisp the (GDFL'd) C
+       powerset function at http://rosettacode.org/wiki/Power_set#C.
+       (todos-powerset): Defalias to powerset-bitwise.
+       (todos-mode-map): Generate from todos-key-bindings instead of
+       listing each key definition.
+       (todos-categories-mode-map): Add two bindings.
+       (todos-filter-items-mode-map): Add some bindings, remove others.
+       (todos-mode): Derive from special-mode; use todos-modes-set-3; add
+       function setting todos-done-separator to
+       window-configuration-change-hook.
+       (todos-unload-hook): Remove function setting todos-done-separator
+       from window-configuration-change-hook.
+       (todos-archive-mode): Derive from todos-mode; use todos-modes-set-3.
+       (todos-edit-mode): Derive from text-mode; use todos-mode-external-set.
+       (todos-categories-mode): Derive from special-mode; use
+       todos-mode-external-set.
+       (todos-filter-items-mode): Derive from special-mode.
+       (todos-quit): Save archive file if it hasn't yet been saved.
+       (todos-display-categories): Delegate all functionality to
+       todos-display-categories-1 and todos-update-categories-display.
+       (todos-toggle-view-done-items): Improve implementation.
+       (todos-highlight-item): Require hl-line.
+       (todos-toggle-display-date-time): Remove argument and make it
+       apply only to whole file.
+       (todos-top-priorities, todos-diary-items, todos-regexp-items)
+       (todos-custom-items): Use todos-special-buffer-name.
+       (todos-add-file): Use todos-short-file-name and
+       todos-reevaluate-defcustoms; remove validation, since it's now
+       done in todos-read-file-name.
+       (todos-add-category): Also update todos-categories-full if non-nil.
+       (todos-delete-category): Delete file after confirmation if only
+       category is deleted.
+       (todos-move-category): Use todos-short-file-name and
+       todos-reevaluate-defcustoms.
+       (todos-insert-item): Fix getting date from the calendar and
+       insertion of time string.
+       (todos-set-date-from-calendar): Enter calendar buffer, suppressing
+       display of diary entries.
+       (todos-edit-multiline): Add optional argument to restrict editing
+       buffer to current item, otherwise make entire buffer (i.e. whole
+       file) editable.
+       (todos-edit-quit): When whole file is editable, check file format
+       validity before killing buffer, and if valid, recalculate
+       categories sexp to be safe.
+       (todos-edit-item-header): Allow choosing date from calendar.
+       (todos-item-done): Handle marked items.
+
 2012-09-19  Stephen Berman  <stephen.berman@gmx.net>
 
        * calendar/todos.el (todos-item-start): Restore commented out code

diff --git a/lisp/calendar/todos.el b/lisp/calendar/todos.el
index 457e49c..b6b6280 100644 (file)
--- a/lisp/calendar/todos.el
+++ b/lisp/calendar/todos.el
@@ -1,6 +1,6 @@
 ;;; Todos.el --- facilities for making and maintaining Todo lists
 
-;; Copyright (C) 1997, 1999, 2001-2011  Free Software Foundation, Inc.
+;; Copyright (C) 1997, 1999, 2001-2012  Free Software Foundation, Inc.
 
 ;; Author: Oliver Seidel <privat@os10000.net>
 ;;         Stephen Berman <stephen.berman@gmx.net>
@@ -8,7 +8,7 @@
 ;; Created: 2 Aug 1997
 ;; Keywords: calendar, todo
 
-;; This file is part of GNU Emacs.
+;; This file is [not yet] 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
@@ -25,30 +25,11 @@
 
 ;;; Commentary:
 
-;; UI
-;; - display
-;;   - show todos in cat
-;;   - show done in cat
-;;   - show catlist
-;;   - show top priorities in all cats
-;;   - show archived
-;; - navigation
-;;   -
-;; - editing
-;;
-;; Internals
-;; - cat props: name, number, todos, done, archived
-;; - item props: priority, date-time, status?
-;; - file format
-;;   - cat begin
-;;   - todo items 0...n
-;;   - empty line
-;;   - done-separator
-;;   - done item 0...n
-
 ;;; Code:
 
 (require 'diary-lib)
+;; For remove-duplicates in todos-insertion-commands-args.
+(eval-when-compile (require 'cl))
 
 ;; ---------------------------------------------------------------------------
 ;;; User options
@@ -56,9 +37,86 @@
 (defgroup todos nil
   "Create and maintain categorized lists of todo items."
   :link '(emacs-commentary-link "todos")
-  :version "24.1"
+  :version "24.2"
   :group 'calendar)
 
+(defcustom todos-files-directory (locate-user-emacs-file "todos/")
+  "Directory where user's Todos files are saved."
+  :type 'directory
+  :group 'todos)
+
+(defun todos-files (&optional archives)
+  "Default value of `todos-files-function'.
+This returns the case-insensitive alphabetically sorted list of
+file truenames in `todos-files-directory' with the extension
+\".todo\".  With non-nil ARCHIVES return the list of archive file
+truenames (those with the extension \".toda\")."
+  (let ((files (if (file-exists-p todos-files-directory)
+                  (mapcar 'file-truename
+                   (directory-files todos-files-directory t
+                                    (if archives "\.toda$" "\.todo$") t)))))
+    (sort files (lambda (s1 s2) (let ((cis1 (upcase s1))
+                                     (cis2 (upcase s2)))
+                                 (string< cis1 cis2))))))
+
+(defcustom todos-files-function 'todos-files
+  "Function returning the value of the variable `todos-files'.
+This function should take an optional argument that, if non-nil,
+makes it return the value of the variable `todos-archives'."
+  :type 'function
+  :group 'todos)
+
+(defun todos-short-file-name (file)
+  "Return short form of Todos FILE.
+This lacks the extension and directory components."
+  (file-name-sans-extension (file-name-nondirectory file)))
+
+(defcustom todos-default-todos-file (car (funcall todos-files-function))
+  "Todos file visited by first session invocation of `todos-show'."
+  :type `(radio ,@(mapcar (lambda (f) (list 'const f))
+                         (mapcar 'todos-short-file-name
+                                 (funcall todos-files-function))))
+  :group 'todos)
+
+;; FIXME: is there a better alternative to this?
+(defun todos-reevaluate-default-file-defcustom ()
+  "Reevaluate defcustom of `todos-default-todos-file'.
+Called after adding or deleting a Todos file."
+  (eval (defcustom todos-default-todos-file (car (funcall todos-files-function))
+         "Todos file visited by first session invocation of `todos-show'."
+         :type `(radio ,@(mapcar (lambda (f) (list 'const f))
+                                 (mapcar 'todos-short-file-name
+                                         (funcall todos-files-function))))
+         :group 'todos)))
+
+(defcustom todos-show-current-file t
+  "Non-nil to make `todos-show' visit the current Todos file.
+Otherwise, `todos-show' always visits `todos-default-todos-file'."
+  :type 'boolean
+  :initialize 'custom-initialize-default
+  :set 'todos-toggle-show-current-file
+  :group 'todos)
+
+(defun todos-toggle-show-current-file (symbol value)
+  "The :set function for user option `todos-show-current-file'."
+  (custom-set-default symbol value)
+  (if value
+      (add-hook 'pre-command-hook 'todos-show-current-file nil t)
+    (remove-hook 'pre-command-hook 'todos-show-current-file t)))
+
+(defcustom todos-visit-files-commands (list 'find-file 'dired-find-file)
+  "List of commands to visit files for `todos-after-find-file'.
+Invoking these commands to visit a Todos or Todos Archive file
+calls `todos-show' or `todos-show-archive', so that the file is
+displayed correctly."
+  :type '(repeat function)
+  :group 'todos)
+
+(defcustom todos-initial-file "Todo"
+  "Default file name offered on adding first Todos file."
+  :type 'string
+  :group 'todos)
+
 (defcustom todos-initial-category "Todo"
   "Default category name offered on initializing a new Todos file."
   :type 'string
@@ -84,17 +142,46 @@ These reflect the priorities of the items in each category."
   :set 'todos-reset-prefix
   :group 'todos)
 
+(defun todos-reset-prefix (symbol value)
+  "The :set function for `todos-prefix' and `todos-number-prefix'."
+  (let ((oldvalue (symbol-value symbol))
+       (files (append todos-files todos-archives)))
+    (custom-set-default symbol value)
+    (when (not (equal value oldvalue))
+      (dolist (f files)
+       (with-current-buffer (find-file-noselect f)
+         (save-window-excursion
+           (todos-show)
+           (save-excursion
+             (widen)
+             (goto-char (point-min))
+             (while (not (eobp))
+               (remove-overlays (point) (point)); 'before-string prefix)
+               (forward-line)))
+           ;; Activate the new setting (save-restriction does not help).
+           (save-excursion (todos-category-select))))))))
+
 ;; FIXME: Update when window-width changes.  Add todos-reset-separator to
 ;; window-configuration-change-hook in todos-mode?  But this depends on the
 ;; value being window-width instead of a constant length.
-(defcustom todos-done-separator (make-string (window-width) ?-)
+(defcustom todos-done-separator (make-string (window-width) ?_)
   "String used to visual separate done from not done items.
 Displayed in a before-string overlay by `todos-toggle-view-done-items'."
   :type 'string
   :initialize 'custom-initialize-default
-  :set 'todos-reset-prefix
+  :set 'todos-reset-separator
   :group 'todos)
 
+;; (defun todos-reset-separator (symbol value)
+;;   "The :set function for `todos-done-separator'
+;; Also added to `window-configuration-change-hook' in Todos mode."
+;;   (let ((oldvalue (symbol-value symbol)))
+;;     (custom-set-default symbol value)
+;;     (when (not (equal value oldvalue))
+;;       (make-string (window-width) ?_)
+;;       ;; (save-excursion (todos-category-select))
+;;       )))
+
 (defcustom todos-done-string "DONE "
   "Identifying string appended to the front of done todos items."
   :type 'string
@@ -102,6 +189,29 @@ Displayed in a before-string overlay by `todos-toggle-view-done-items'."
   :set 'todos-reset-done-string
   :group 'todos)
 
+(defun todos-reset-done-string (symbol value)
+  "The :set function for user option `todos-done-string'."
+  (let ((oldvalue (symbol-value symbol))
+       (files (append todos-files todos-archives)))
+    (custom-set-default symbol value)
+    ;; Need to reset this to get font-locking right.
+    (setq todos-done-string-start
+         (concat "^\\[" (regexp-quote todos-done-string)))
+    (when (not (equal value oldvalue))
+      (dolist (f files)
+       (with-current-buffer (find-file-noselect f)
+         (let (buffer-read-only)
+           (widen)
+           (goto-char (point-min))
+           (while (not (eobp))
+             (if (re-search-forward
+                  (concat "^" (regexp-quote todos-nondiary-start)
+                          "\\(" (regexp-quote oldvalue) "\\)")
+                  nil t)
+                 (replace-match value t t nil 1)
+               (forward-line)))
+           (todos-category-select)))))))
+
 (defcustom todos-comment-string "COMMENT"
   "String inserted before optional comment appended to done item."
   :type 'string
@@ -109,6 +219,27 @@ Displayed in a before-string overlay by `todos-toggle-view-done-items'."
   :set 'todos-reset-comment-string
   :group 'todos)
 
+(defun todos-reset-comment-string (symbol value)
+  "The :set function for user option `todos-comment-string'."
+  (let ((oldvalue (symbol-value symbol))
+       (files (append todos-files todos-archives)))
+    (custom-set-default symbol value)
+    (when (not (equal value oldvalue))
+      (dolist (f files)
+       (with-current-buffer (find-file-noselect f)
+         (let (buffer-read-only)
+           (save-excursion
+             (widen)
+             (goto-char (point-min))
+             (while (not (eobp))
+               (if (re-search-forward
+                    (concat
+                            "\\[\\(" (regexp-quote oldvalue) "\\): [^]]*\\]")
+                    nil t)
+                   (replace-match value t t nil 1)
+                 (forward-line)))
+             (todos-category-select))))))))
+
 (defcustom todos-show-with-done nil
   "Non-nil to display done items in all categories."
   :type 'boolean
@@ -119,147 +250,98 @@ Displayed in a before-string overlay by `todos-toggle-view-done-items'."
 Argument CAT is the name of the current Todos category.
 This function is the value of the user variable
 `todos-mode-line-function'."
-  (let ((file (file-name-sans-extension
-              (file-name-nondirectory todos-current-todos-file))))
-  (format "%s category %d: %s" file todos-category-number cat)))
+  (let ((file (todos-short-file-name todos-current-todos-file)))
+    (format "%s category %d: %s" file todos-category-number cat)))
 
 (defcustom todos-mode-line-function 'todos-mode-line-control
   "Function that returns a mode line control for Todos buffers.
-The function is expected to take one argument that holds the name
-of the current Todos category.  The resulting control becomes the
-local value of `mode-line-buffer-identification' in each Todos
-buffer."
-  :type 'function
-  :group 'todos)
-
-(defcustom todos-files-directory (locate-user-emacs-file "todos/")
-  "Directory where user's Todos files are saved."
-  :type 'directory
-  :group 'todos)
-
-(defun todos-files (&optional archives)
-  "Default value of `todos-files-function'.
-This returns the case-insensitive alphabetically sorted list of
-file truenames in `todos-files-directory' with the extension
-\".todo\".  With non-nil ARCHIVES return the list of archive file
-truenames (those with the extension \".toda\")."
-  (let ((files (mapcar 'file-truename
-                      (directory-files todos-files-directory t
-                                       (if archives "\.toda$" "\.todo$") t))))
-    (sort files (lambda (s1 s2) (let ((cis1 (upcase s1))
-                                     (cis2 (upcase s2)))
-                                 (string< cis1 cis2))))))
-
-(defcustom todos-files-function 'todos-files
-  "Function returning the value of the variable `todos-files'.
-This function should take an optional argument that, if non-nil,
-makes it return the value of the variable `todos-archives'."
-  :type 'function
-  :group 'todos)
-
-(defcustom todos-filter-function nil
-  ""
+The function expects one argument holding the name of the current
+Todos category.  The resulting control becomes the local value of
+`mode-line-buffer-identification' in each Todos buffer."
   :type 'function
   :group 'todos)
 
-(defcustom todos-priorities-rules (list)
-  "List of rules for choosing top priorities of each Todos file.
-The rules should be set interactively by invoking
-`todos-set-top-priorities'.
-
-Each rule is a list whose first element is a member of
-`todos-files', whose second element is a number specifying the
-default number of top priority items for the categories in that
-file, and whose third element is an alist whose elements are
-conses of a category name in that file and the number of top
-priority items in that category that `todos-top-priorities' shows
-by default, which overrides the number for the file."
-  :type 'list
-  :group 'todos)
-
-(defcustom todos-merged-files nil
-  "List of files for `todos-merged-top-priorities'."
-  :type `(set ,@(mapcar (lambda (x) (list 'const x))
-                       (funcall todos-files-function)))
-  :group 'todos)
-
-(defcustom todos-prompt-merged-files nil
-  "Non-nil to prompt for merging files for `todos-filter-items'."
-  :type 'boolean
-  :group 'todos)
-
-(defcustom todos-show-current-file t
-  "Non-nil to make `todos-show' visit the current Todos file.
-Otherwise, `todos-show' always visits `todos-default-todos-file'."
-  :type 'boolean
-  :initialize 'custom-initialize-default
-  :set 'todos-toggle-show-current-file
-  :group 'todos)
-
-;; FIXME: omit second sentence from doc string?
-(defcustom todos-default-todos-file (car (funcall todos-files-function))
-  "Todos file visited by first session invocation of `todos-show'.
-Normally this should be set by invoking `todos-change-default-file'
-either directly or as a side effect of `todos-add-file'."
-  :type `(radio ,@(mapcar (lambda (x) (list 'const x))
-                         (funcall todos-files-function)))
-  :group 'todos)
-
-(defcustom todos-visit-files-commands (list 'find-file 'dired-find-file)
-  "List of commands to visit files for `todos-after-find-file'.
-Invoking these commands to visit a Todos or Todos Archive file
-calls `todos-show' or `todos-show-archive', so that the file is
-displayed correctly."
-  :type '(repeat function)
-  :group 'todos)
-
-(defcustom todos-categories-buffer "*Todos Categories*"
-  "Name of buffer displayed by `todos-display-categories'."
+(defun todos-special-buffer-name (buffer-type file-list)
+  "Rename Todos special buffer.
+The new name is concatenated from the string BUFFER-TYPE and the
+names of the files in FILE-LIST.  Used in the mode-list of
+buffers displaying top priorities, diary items, regexp items
+etc. for single and multiple files."
+  (let* ((flist (if (listp file-list) file-list (list file-list)))
+        (multi (> (length flist) 1))
+        (fnames (mapconcat (lambda (f) (todos-short-file-name f))
+                          flist ", ")))
+    (rename-buffer (format (concat "%s for file" (if multi "s" "")
+                                  " \"%s\"") buffer-type fnames))))
+
+(defcustom todos-filter-buffer "Todos filtered items"
+  "Initial name of buffer in Todos Filter mode."
   :type 'string
   :group 'todos)
 
-(defcustom todos-categories-category-label "Category"
-  "Category button label in `todos-categories-buffer'."
+(defcustom todos-top-priorities-buffer "Todos top priorities"
+  "Name of buffer displaying top priorities in Todos Filter mode."
   :type 'string
   :group 'todos)
 
-(defcustom todos-categories-todo-label "Todo"
-  "Todo button label in `todos-categories-buffer'."
+(defcustom todos-diary-items-buffer "Todos diary items"
+  "Name of buffer displaying diary items in Todos Filter mode."
   :type 'string
   :group 'todos)
 
-(defcustom todos-categories-diary-label "Diary"
-  "Diary button label in `todos-categories-buffer'."
+(defcustom todos-regexp-items-buffer "Todos regexp items"
+  "Name of buffer displaying regexp items in Todos Filter mode."
   :type 'string
   :group 'todos)
 
-(defcustom todos-categories-done-label "Done"
-  "Done button label in `todos-categories-buffer'."
+(defcustom todos-custom-items-buffer "Todos custom items"
+  "Name of buffer displaying custom items in Todos Filter mode."
   :type 'string
   :group 'todos)
 
-(defcustom todos-categories-archived-label "Archived"
-  "Archived button label in `todos-categories-buffer'."
-  :type 'string
+(defcustom todos-priorities-rules nil
+  "List of rules giving how many items `todos-top-priorities' shows.
+This variable should be set interactively by
+`\\[todos-set-top-priorities-in-file]' or
+`\\[todos-set-top-priorities-in-category]'.
+
+Each rule is a list of the form (FILE NUM ALIST), where FILE is a
+member of `todos-files', NUM is a number specifying the default
+number of top priority items for each category in that file, and
+ALIST, when non-nil, consists of conses of a category name in
+FILE and a number specifying the default number of top priority
+items in that category, which overrides NUM."
+  :type 'list
   :group 'todos)
 
-(defcustom todos-categories-totals-label "Totals"
-  "String to label total item counts in `todos-categories-buffer'."
-  :type 'string
+(defcustom todos-show-priorities 1
+  "Default number of top priorities shown by `todos-top-priorities'."
+  :type 'integer
   :group 'todos)
 
-(defcustom todos-categories-number-separator " | "
-  "String between number and category in `todos-categories-buffer'.
-This separates the number from the category name in the default
-categories display according to priority."
-  :type 'string
+(defcustom todos-filter-function nil
+  ""
+  :type 'function
   :group 'todos)
 
-(defcustom todos-categories-align 'center
-  "Alignment of category names in `todos-categories-buffer'."
-  :type '(radio (const left) (const center) (const right))
+(defcustom todos-filter-files nil
+  "List of default files for multifile item filtering."
+  :type `(set ,@(mapcar (lambda (f) (list 'const f))
+                       (mapcar 'todos-short-file-name
+                               (funcall todos-files-function))))
   :group 'todos)
 
+;; FIXME: is there a better alternative to this?
+(defun todos-reevaluate-filter-files-defcustom ()
+  "Reevaluate defcustom of `todos-filter-files'.
+Called after adding or deleting a Todos file."
+  (eval (defcustom todos-filter-files nil
+         "List of files for multifile item filtering."
+         :type `(set ,@(mapcar (lambda (f) (list 'const f))
+                               (mapcar 'todos-short-file-name
+                                       (funcall todos-files-function))))
+         :group 'todos)))
+
 (defcustom todos-ignore-archived-categories nil
   "Non-nil to ignore categories with only archived items.
 When non-nil such categories are omitted from `todos-categories'
@@ -273,21 +355,17 @@ archived categories."
   :set 'todos-reset-categories
   :group 'todos)
 
-;; FIXME
-(defcustom todos-edit-buffer "*Todos Edit*"
-  "Name of current buffer in Todos Edit mode."
-  :type 'string
-  :group 'todos)
-
-;; (defcustom todos-edit-buffer "*Todos Top Priorities*"
-;;   "TODO Edit buffer name."
-;;   :type 'string
-;;   :group 'todos)
-
-;; (defcustom todos-edit-buffer "*Todos Diary Entries*"
-;;   "TODO Edit buffer name."
-;;   :type 'string
-;;   :group 'todos)
+(defun todos-reset-categories (symbol value)
+  "The :set function for `todos-ignore-archived-categories'."
+  (custom-set-default symbol value)
+  (dolist (f (funcall todos-files-function))
+    (with-current-buffer (find-file-noselect f)
+      (if value
+         (setq todos-categories-full todos-categories
+               todos-categories (todos-truncate-categories-list))
+       (setq todos-categories todos-categories-full
+             todos-categories-full nil))
+      (todos-category-select))))
 
 (defcustom todos-use-only-highlighted-region t
   "Non-nil to enable inserting only highlighted region as new item."
@@ -317,29 +395,70 @@ the diary date."
   :initialize 'custom-initialize-default
   :set 'todos-reset-nondiary-marker)
 
+(defun todos-reset-nondiary-marker (symbol value)
+  "The :set function for user option `todos-nondiary-marker'."
+  (let ((oldvalue (symbol-value symbol))
+       (files (append todos-files todos-archives)))
+    (custom-set-default symbol value)
+    ;; Need to reset these to get font-locking right.
+    (setq todos-nondiary-start (nth 0 todos-nondiary-marker)
+         todos-nondiary-end (nth 1 todos-nondiary-marker)
+         todos-date-string-start
+         ;; See comment in defvar of `todos-date-string-start'.
+         (concat "^\\(" (regexp-quote todos-nondiary-start) "\\|"
+                 (regexp-quote diary-nonmarking-symbol) "\\)?"))
+    (when (not (equal value oldvalue))
+      (dolist (f files)
+       (with-current-buffer (find-file-noselect f)
+         (let (buffer-read-only)
+           (widen)
+           (goto-char (point-min))
+           (while (not (eobp))
+             (if (re-search-forward
+                  (concat "^\\(" todos-done-string-start "[^][]+] \\)?"
+                          "\\(?1:" (regexp-quote (car oldvalue))
+                          "\\)" todos-date-pattern "\\( "
+                          diary-time-regexp "\\)?\\(?2:"
+                          (regexp-quote (cadr oldvalue)) "\\)")
+                  nil t)
+                 (progn
+                   (replace-match (nth 0 value) t t nil 1)
+                   (replace-match (nth 1 value) t t nil 2))
+               (forward-line)))
+           (todos-category-select)))))))
+
 (defcustom todos-print-function 'ps-print-buffer-with-faces
   "Function called to print buffer content; see `todos-print'."
   :type 'symbol
   :group 'todos)
 
-;; FIXME: rename, change meaning of zero, refer to todos-priorities-rules
-(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
+(defcustom todos-completion-ignore-case nil
+  "Non-nil means case of user input in `todos-read-*' is ignored."
+  :type 'boolean
   :group 'todos)
 
-(defcustom todos-completion-ignore-case t ;; FIXME: nil for release?
-  "Non-nil means don't consider case significant in `todos-read-category'."
+(defcustom todos-highlight-item nil
+  "Non-nil means highlight items at point."
   :type 'boolean
+  :initialize 'custom-initialize-default
+  :set 'todos-reset-highlight-item
   :group 'todos)
 
+(defun todos-reset-highlight-item (symbol value)
+  "The :set function for `todos-highlight-item'."
+  (let ((oldvalue (symbol-value symbol))
+       (files (append todos-files todos-archives)))
+    (custom-set-default symbol value)
+    (when (not (equal value oldvalue))
+      (dolist (f files)
+       (let ((buf (get-file-buffer f)))
+         (when buf
+           (with-current-buffer buf
+             (require 'hl-line)
+             (if value
+                 (hl-line-mode 1)
+               (hl-line-mode -1)))))))))
+
 (defcustom todos-always-add-time-string nil
   "Non-nil adds current time to a new item's date header by default.
 When the Todos insertion commands have a non-nil \"maybe-notime\"
@@ -350,99 +469,341 @@ current time, if nil, they include it."
   :group 'todos)
 
 (defcustom todos-wrap-lines t
-  "Non-nil to wrap long lines by `todos-line-wrapping-function'." ;FIXME
+  "Non-nil to wrap long lines via `todos-line-wrapping-function'."
   :group 'todos
   :type 'boolean)
 
 (defcustom todos-line-wrapping-function 'todos-wrap-and-indent
-  "Function called when `todos-wrap-lines' is non-nil." ;FIXME
+  "Line wrapping function used with non-nil `todos-wrap-lines'."
   :group 'todos
   :type 'function)
 
-(defcustom todos-indent-to-here 6
-    "Number of spaces `todos-line-wrapping-function' indents to."
-  :type 'integer
+(defun todos-wrap-and-indent ()
+  "Use word wrapping on long lines and indent with a wrap prefix.
+The amount of indentation is given by user option
+`todos-indent-to-here'."
+  (set (make-local-variable 'word-wrap) t)
+  (set (make-local-variable 'wrap-prefix) (make-string todos-indent-to-here 32))
+  (unless (member '(continuation) fringe-indicator-alist)
+    (push '(continuation) fringe-indicator-alist)))
+
+;; FIXME: :set function (otherwise change takes effect only after revisiting)
+(defcustom todos-indent-to-here 6
+  "Number of spaces `todos-line-wrapping-function' indents to."
+  :type '(integer :validate
+                 (lambda (widget)
+                   (unless (> (widget-value widget) 0)
+                     (widget-put widget :error
+                                 "Invalid value: must be a positive integer")
+                     widget)))
+  :group 'todos)
+
+(defun todos-indent ()
+  "Indent from point to `todos-indent-to-here'."
+  (indent-to todos-indent-to-here todos-indent-to-here))
+
+(defcustom todos-todo-mode-date-time-regexp
+  (concat "\\(?1:[0-9]\\{4\\}\\)-\\(?2:[0-9]\\{2\\}\\)-"
+         "\\(?3:[0-9]\\{2\\}\\) \\(?4:[0-9]\\{2\\}:[0-9]\\{2\\}\\)")
+  "Regexp matching legacy todo-mode.el item date-time strings.
+In order for `todos-convert-legacy-files' to correctly convert this
+string to the current Todos format, the regexp must contain four
+explicitly numbered groups (see `(elisp) Regexp Backslash'),
+where group 1 matches a string for the year, group 2 a string for
+the month, group 3 a string for the day and group 4 a string for
+the time.  The default value converts date-time strings built
+using the default value of `todo-time-string-format' from
+todo-mode.el."
+  :type 'regexp
   :group 'todos)
 
+(defgroup todos-categories nil
+  "Faces for Todos Categories mode."
+  :version "24.2"
+  :group 'todos)
+
+(defcustom todos-categories-category-label "Category"
+  "Category button label in Todos Categories mode."
+  :type 'string
+  :group 'todos-categories)
+
+(defcustom todos-categories-todo-label "Todo"
+  "Todo button label in Todos Categories mode."
+  :type 'string
+  :group 'todos-categories)
+
+(defcustom todos-categories-diary-label "Diary"
+  "Diary button label in Todos Categories mode."
+  :type 'string
+  :group 'todos-categories)
+
+(defcustom todos-categories-done-label "Done"
+  "Done button label in Todos Categories mode."
+  :type 'string
+  :group 'todos-categories)
+
+(defcustom todos-categories-archived-label "Archived"
+  "Archived button label in Todos Categories mode."
+  :type 'string
+  :group 'todos-categories)
+
+(defcustom todos-categories-totals-label "Totals"
+  "String to label total item counts in Todos Categories mode."
+  :type 'string
+  :group 'todos-categories)
+
+(defcustom todos-categories-number-separator " | "
+  "String between number and category in Todos Categories mode.
+This separates the number from the category name in the default
+categories display according to priority."
+  :type 'string
+  :group 'todos-categories)
+
+(defcustom todos-categories-align 'center
+  "Alignment of category names in Todos Categories mode."
+  :type '(radio (const left) (const center) (const right))
+  :group 'todos-categories)
+
 ;; ---------------------------------------------------------------------------
 ;;; Faces
 
 (defgroup todos-faces nil
   "Faces for the Todos modes."
-  :version "24.1"
+  :version "24.2"
   :group 'todos)
 
 (defface todos-prefix-string
-  '((t :inherit font-lock-constant-face))
+  ;; '((t :inherit font-lock-constant-face))
+  '((((class grayscale) (background light))
+     (:foreground "LightGray" :weight bold :underline t))
+    (((class grayscale) (background dark))
+     (:foreground "Gray50" :weight bold :underline t))
+    (((class color) (min-colors 88) (background light)) (:foreground "dark cyan"))
+    (((class color) (min-colors 88) (background dark)) (:foreground "Aquamarine"))
+    (((class color) (min-colors 16) (background light)) (:foreground "CadetBlue"))
+    (((class color) (min-colors 16) (background dark)) (:foreground "Aquamarine"))
+    (((class color) (min-colors 8)) (:foreground "magenta"))
+    (t (:weight bold :underline t)))
   "Face for Todos prefix string."
   :group 'todos-faces)
 
 (defface todos-mark
-  '((t :inherit font-lock-warning-face))
+  ;; '((t :inherit font-lock-warning-face))
+  '((((class color)
+      (min-colors 88)
+      (background light))
+     (:weight bold :foreground "Red1"))
+    (((class color)
+      (min-colors 88)
+      (background dark))
+     (:weight bold :foreground "Pink"))
+    (((class color)
+      (min-colors 16)
+      (background light))
+     (:weight bold :foreground "Red1"))
+    (((class color)
+      (min-colors 16)
+      (background dark))
+     (:weight bold :foreground "Pink"))
+    (((class color)
+      (min-colors 8))
+     (:foreground "red"))
+    (t
+     (:weight bold :inverse-video t)))
   "Face for marks on Todos items."
   :group 'todos-faces)
 
 (defface todos-button
-  '((t :inherit widget-field))
+  ;; '((t :inherit widget-field))
+  '((((type tty))
+     (:foreground "black" :background "yellow3"))
+    (((class grayscale color)
+      (background light))
+     (:background "gray85"))
+    (((class grayscale color)
+      (background dark))
+     (:background "dim gray"))
+    (t
+     (:slant italic)))
   "Face for buttons in todos-display-categories."
   :group 'todos-faces)
 
 (defface todos-sorted-column
-  '((t :inherit fringe))
+  ;; '((t :inherit fringe))
+  '((((class color)
+      (background light))
+     (:foreground "grey95"))
+    (((class color)
+      (background dark))
+     (:foreground "grey10"))
+    (t
+     (:foreground "gray")))
   "Face for buttons in todos-display-categories."
   :group 'todos-faces)
 
 (defface todos-archived-only
-  '((t (:inherit (shadow))))
+  ;; '((t (:inherit (shadow))))
+  '((((class color)
+      (background light))
+     (:foreground "grey50"))
+    (((class color)
+      (background dark))
+     (:foreground "grey70"))
+    (t
+     (:foreground "gray")))
   "Face for archived-only categories in todos-display-categories."
   :group 'todos-faces)
 
 (defface todos-search
-  '((t :inherit match))
+  ;; '((t :inherit match))
+  '((((class color)
+      (min-colors 88)
+      (background light))
+     (:background "yellow1"))
+    (((class color)
+      (min-colors 88)
+      (background dark))
+     (:background "RoyalBlue3"))
+    (((class color)
+      (min-colors 8)
+      (background light))
+     (:foreground "black" :background "yellow"))
+    (((class color)
+      (min-colors 8)
+      (background dark))
+     (:foreground "white" :background "blue"))
+    (((type tty)
+      (class mono))
+     (:inverse-video t))
+    (t
+     (:background "gray")))
   "Face for matches found by todos-search."
   :group 'todos-faces)
 
+(defface todos-diary-expired
+  ;; '((t :inherit font-lock-warning-face))
+  '((((class color)
+      (min-colors 16))
+     (:weight bold :foreground "DarkOrange"))
+    (((class color))
+     (:weight bold :foreground "yellow"))
+    (t
+     (:weight bold)))
+  "Face for expired dates of diary items."
+  :group 'todos-faces)
+(defvar todos-diary-expired-face 'todos-diary-expired)
+
 (defface todos-date
   '((t :inherit diary))
-  "Face for Todos prefix string."
+  "Face for the date string of a Todos item."
   :group 'todos-faces)
 (defvar todos-date-face 'todos-date)
 
 (defface todos-time
   '((t :inherit diary-time))
-  "Face for Todos prefix string."
+  "Face for the time string of a Todos item."
   :group 'todos-faces)
 (defvar todos-time-face 'todos-time)
 
 (defface todos-done
-  '((t :inherit font-lock-comment-face))
+  ;; '((t :inherit font-lock-comment-face))
+  '((((class grayscale)
+      (background light))
+     (:slant italic :weight bold :foreground "DimGray"))
+    (((class grayscale)
+      (background dark))
+     (:slant italic :weight bold :foreground "LightGray"))
+    (((class color)
+      (min-colors 88)
+      (background light))
+     (:foreground "Firebrick"))
+    (((class color)
+      (min-colors 88)
+      (background dark))
+     (:foreground "chocolate1"))
+    (((class color)
+      (min-colors 16)
+      (background light))
+     (:foreground "red"))
+    (((class color)
+      (min-colors 16)
+      (background dark))
+     (:foreground "red1"))
+    (((class color)
+      (min-colors 8)
+      (background light))
+     (:foreground "red"))
+    (((class color)
+      (min-colors 8)
+      (background dark))
+     (:foreground "yellow"))
+    (t
+     (:slant italic :weight bold)))
   "Face for done Todos item header string."
   :group 'todos-faces)
 (defvar todos-done-face 'todos-done)
 
 (defface todos-comment
-  '((t :inherit font-lock-comment-face))
+  '((t :inherit todos-done))
   "Face for comments appended to done Todos items."
   :group 'todos-faces)
 (defvar todos-comment-face 'todos-comment)
 
 (defface todos-done-sep
-  '((t :inherit font-lock-type-face))
+  ;; '((t :inherit font-lock-type-face))
+  '((((class grayscale)
+      (background light))
+     (:weight bold :foreground "Gray90"))
+    (((class grayscale)
+      (background dark))
+     (:weight bold :foreground "DimGray"))
+    (((class color)
+      (min-colors 88)
+      (background light))
+     (:foreground "ForestGreen"))
+    (((class color)
+      (min-colors 88)
+      (background dark))
+     (:foreground "PaleGreen"))
+    (((class color)
+      (min-colors 16)
+      (background light))
+     (:foreground "ForestGreen"))
+    (((class color)
+      (min-colors 16)
+      (background dark))
+     (:foreground "PaleGreen"))
+    (((class color)
+      (min-colors 8))
+     (:foreground "green"))
+    (t
+     (:underline t :weight bold)))
   "Face for separator string bewteen done and not done Todos items."
   :group 'todos-faces)
 (defvar todos-done-sep-face 'todos-done-sep)
 
 (defvar todos-font-lock-keywords
   (list
+   ;; '(todos-nondiary-marker-matcher 1 todos-nondiary-face t)
+   ;; '(todos-nondiary-marker-matcher 2 todos-nondiary-face t)
+   '(todos-nondiary-marker-matcher 1 todos-done-sep-face t)
+   '(todos-nondiary-marker-matcher 2 todos-done-sep-face t)
+   ;; This is the face used by diary-lib.el.
+   '(todos-diary-nonmarking-matcher 1 font-lock-constant-face t)
    '(todos-date-string-matcher 1 todos-date-face t)
    '(todos-time-string-matcher 1 todos-time-face t)
    '(todos-done-string-matcher 0 todos-done-face t)
    '(todos-comment-string-matcher 1 todos-done-face t)
-   '(todos-category-string-matcher 1 todos-done-sep-face t))
-  "Font-locking for Todos mode.")
+   ;; '(todos-category-string-matcher 1 todos-done-sep-face t)
+   '(todos-category-string-matcher-1 1 todos-done-sep-face t t)
+   '(todos-category-string-matcher-2 1 todos-done-sep-face t t)
+   '(todos-diary-expired-matcher 1 todos-diary-expired-face t)
+   '(todos-diary-expired-matcher 2 todos-diary-expired-face t t)
+   )
+  "Font-locking for Todos modes.")
 
 ;; ---------------------------------------------------------------------------
-;;; Modes setup
+;;; Todos mode local variables and hook functions
 
 (defvar todos-files (funcall todos-files-function)
   "List of truenames of user's Todos files.")
@@ -450,34 +811,29 @@ current time, if nil, they include it."
 (defvar todos-archives (funcall todos-files-function t)
   "List of truenames of user's Todos archives.")
 
-(defvar todos-categories nil
-  "Alist of categories in the current Todos file.
-The elements are cons cells whose car is a category name and
-whose cdr is a vector of the category's item counts.  These are,
-in order, the numbers of todo items, todo items included in the
-Diary, done items and archived items.")
-
-(defvar todos-categories-full nil
-  "Variable holding non-truncated copy of `todos-categories'.
-Set when `todos-ignore-archived-categories' is set to non-nil, to
-restore full `todos-categories' list when
-`todos-ignore-archived-categories' is reset to nil.")
-
 (defvar todos-current-todos-file nil
   "Variable holding the name of the currently active Todos file.")
-;; Automatically set by `todos-switch-todos-file'.")
 
-;; FIXME: Add function to kill-buffer-hook that sets this to the latest
-;; existing Todos file or else todos-default-todos-file on killing the buffer
-;; of a Todos file
-(defvar todos-global-current-todos-file nil
-  "Variable holding name of current Todos file.
-Used by functions called from outside of Todos mode to visit the
-current Todos file rather than the default Todos file (i.e. when
-users option `todos-show-current-file' is non-nil).")
+(defun todos-show-current-file ()
+  "Visit current instead of default Todos file with `todos-show'.
+This function is added to `pre-command-hook' when user option
+`todos-show-current-file' is set to non-nil."
+  (setq todos-global-current-todos-file todos-current-todos-file))
+  ;; (and (eq major-mode 'todos-mode)
+       ;; (setq todos-global-current-todos-file (buffer-file-name))))
+
+(defun todos-after-find-file ()
+  "Show Todos files correctly when visited from outside of Todos mode."
+  (and (member this-command todos-visit-files-commands)
+       (= (- (point-max) (point-min)) (buffer-size))
+       (member major-mode '(todos-mode todos-archive-mode))
+       (todos-category-select)))
 
 (defun todos-reset-global-current-todos-file ()
-  ""
+  "Update the value of `todos-global-current-todos-file'.
+This becomes the latest existing Todos file or, if there is none,
+the value of `todos-default-todos-file'.
+This function is added to `kill-buffer-hook' in Todos mode."
   (let ((buflist (copy-sequence (buffer-list)))
        (cur todos-global-current-todos-file))
     (catch 'done
@@ -492,23 +848,77 @@ users option `todos-show-current-file' is non-nil).")
     (if (equal cur todos-global-current-todos-file)
        (setq todos-global-current-todos-file todos-default-todos-file))))    
 
+(defvar todos-categories nil
+  "Alist of categories in the current Todos file.
+The elements are cons cells whose car is a category name and
+whose cdr is a vector of the category's item counts.  These are,
+in order, the numbers of todo items, todo items included in the
+Diary, done items and archived items.")
+
+(defvar todos-categories-full nil
+  "Variable holding non-truncated copy of `todos-categories'.
+Set when `todos-ignore-archived-categories' is set to non-nil, to
+restore full `todos-categories' list when
+`todos-ignore-archived-categories' is reset to nil.")
+
+(defvar todos-categories-with-marks nil
+  "Alist of categories and number of marked items they contain.")
+
 (defvar todos-category-number 1
   "Variable holding the number of the current Todos category.
-This number is one more than the index of the category in
-`todos-categories'.")
+Todos categories are numbered starting from 1.")
 
 (defvar todos-first-visit t
   "Non-nil if first display of this file in the current session.
 See `todos-display-categories-first'.")
 
-;; FIXME: rename?
-(defvar todos-tmp-buffer-name " *todo tmp*")
+(defvar todos-show-done-only nil
+  "If non-nil display only done items in current category.
+Set by `todos-toggle-show-done-only' and used by
+`todos-category-select'.")
 
-(defvar todos-category-beg "--==-- "
-  "String marking beginning of category (inserted with its name).")
+;; ---------------------------------------------------------------------------
+;;; Global variables and helper functions
 
-(defvar todos-category-done "==--== DONE "
-  "String marking beginning of category's done items.")
+(defvar todos-global-current-todos-file nil
+  "Variable holding name of current Todos file.
+Used by functions called from outside of Todos mode to visit the
+current Todos file rather than the default Todos file (i.e. when
+users option `todos-show-current-file' is non-nil).")
+
+(defun todos-reevaluate-defcustoms ()
+  "Reevaluate defcustoms that show list of Todos files."
+  (custom-set-default 'todos-default-todos-file
+                     (symbol-value 'todos-default-todos-file))
+  (todos-reevaluate-default-file-defcustom)
+  (custom-set-default 'todos-filter-files (symbol-value 'todos-filter-files))
+  (todos-reevaluate-filter-files-defcustom))
+
+(defvar todos-edit-buffer "*Todos Edit*"
+  "Name of current buffer in Todos Edit mode.")
+
+(defvar todos-categories-buffer "*Todos Categories*"
+  "Name of buffer in Todos Categories mode.")
+
+(defvar todos-print-buffer "*Todos Print*"
+  "Name of buffer containing printable Todos text.")
+
+(defvar todos-date-pattern
+  (let ((dayname (diary-name-pattern calendar-day-name-array nil t)))
+    (concat "\\(?:" dayname "\\|"
+           (let ((dayname)
+                 ;; FIXME: how to choose between abbreviated and unabbreviated
+                 ;; month name?
+                 (monthname (format "\\(?:%s\\|\\*\\)"
+                                    (diary-name-pattern
+                                     calendar-month-name-array
+                                     calendar-month-abbrev-array t)))
+                 (month "\\(?:[0-9]+\\|\\*\\)")
+                 (day "\\(?:[0-9]+\\|\\*\\)")
+                 (year "-?\\(?:[0-9]+\\|\\*\\)"))
+             (mapconcat 'eval calendar-date-display-form ""))
+           "\\)"))
+  "Regular expression matching a Todos date header.")
 
 (defvar todos-nondiary-start (nth 0 todos-nondiary-marker)
   "String inserted before item date to block diary inclusion.")
@@ -516,3580 +926,3909 @@ See `todos-display-categories-first'.")
 (defvar todos-nondiary-end (nth 1 todos-nondiary-marker)
   "String inserted after item date matching `todos-nondiary-start'.")
 
-(defvar todos-show-done-only nil
-  "If non-nil display only done items in current category.
-Set by `todos-toggle-show-done-only' and used by
-`todos-category-select'.")
+;; By itself this matches anything, because of the `?'; however, it's only
+;; used in the context of `todos-date-pattern' (but Emacs Lisp lacks
+;; lookahead).
+(defvar todos-date-string-start
+  (concat "^\\(" (regexp-quote todos-nondiary-start) "\\|"
+         (regexp-quote diary-nonmarking-symbol) "\\)?")
+  "Regular expression matching part of item header before the date.")
 
-;;; Todos insertion commands, key bindings and keymap
+(defvar todos-done-string-start
+  (concat "^\\[" (regexp-quote todos-done-string))
+  "Regular expression matching start of done item.")
 
-;; http://rosettacode.org/wiki/Power_set#Common_Lisp (GFDL)
-(defun powerset (l)
-  (if (null l)
-      (list nil)
-    (let ((prev (powerset (cdr l))))
-      (append (mapcar #'(lambda (elt) (cons (car l) elt)) prev)
-             prev))))
+(defun todos-date-string-matcher (lim)
+  "Search for Todos date string within LIM for font-locking."
+  (re-search-forward
+   (concat todos-date-string-start "\\(?1:" todos-date-pattern "\\)") lim t))
 
-;; Return list of lists of non-nil atoms produced from ARGLIST.  The elements
-;; of ARGLIST may be atoms or lists.
-(defun todos-gen-arglists (arglist)
-  (let (arglists)
-    (while arglist
-      (let ((arg (pop arglist)))
-       (cond ((symbolp arg)
-              (setq arglists (if arglists
-                                 (mapcar (lambda (l) (push arg l)) arglists)
-                               (list (push arg arglists)))))
-             ((listp arg)
-              (setq arglists
-                    (mapcar (lambda (a)
-                              (if (= 1 (length arglists))
-                                  (apply (lambda (l) (push a l)) arglists)
-                                (mapcar (lambda (l) (push a l)) arglists)))
-                            arg))))))
-    (setq arglists (mapcar 'reverse (apply 'append (mapc 'car arglists))))))
+(defun todos-time-string-matcher (lim)
+  "Search for Todos time string within LIM for font-locking."
+  (re-search-forward (concat todos-date-string-start todos-date-pattern
+                            " \\(?1:" diary-time-regexp "\\)") lim t))
 
-(defvar todos-insertion-commands-args-genlist
-  '(diary nonmarking (calendar date dayname) time (here region))
-  "Generator list for argument lists of Todos insertion commands.")
+(defun todos-nondiary-marker-matcher (lim)
+  "Search for Todos nondiary markers within LIM for font-locking."
+  (re-search-forward (concat "^\\(?1:" (regexp-quote todos-nondiary-start) "\\)"
+                            todos-date-pattern "\\(?: " diary-time-regexp
+                            "\\)?\\(?2:" (regexp-quote todos-nondiary-end) "\\)")
+                    lim t))
 
-(eval-when-compile (require 'cl))      ; remove-duplicates
+(defun todos-diary-nonmarking-matcher (lim)
+  "Search for diary nonmarking symbol within LIM for font-locking."
+  (re-search-forward (concat "^\\(?1:" (regexp-quote diary-nonmarking-symbol)
+                            "\\)" todos-date-pattern) lim t))
+
+(defun todos-diary-expired-matcher (lim)
+  "Search for expired diary item date within LIM for font-locking."
+  (when (re-search-forward (concat "^\\(?:"
+                                  (regexp-quote diary-nonmarking-symbol)
+                                  "\\)?\\(?1:" todos-date-pattern "\\) \\(?2:"
+                                  diary-time-regexp "\\)?") lim t)
+    (let* ((date (match-string-no-properties 1))
+          (time (match-string-no-properties 2))
+          ;; days-between needs a non-empty time string.
+          (date-time (concat date " " (or time "00:00"))))
+      (or (and (not (string-match ".+day\\|\\*" date))
+              (< (days-between date-time (current-time-string)) 0))
+         (todos-diary-expired-matcher lim)))))
 
-(defvar todos-insertion-commands-args
-  (let ((argslist (todos-gen-arglists todos-insertion-commands-args-genlist))
-       res new)
-    (setq res (remove-duplicates
-              (apply 'append (mapcar 'powerset argslist)) :test 'equal))
-    (dolist (l res)
-      (unless (= 5 (length l))
-       (let ((v (make-vector 5 nil)) elt)
-         (while l
-           (setq elt (pop l))
-           (cond ((eq elt 'diary)
-                  (aset v 0 elt))
-                 ((eq elt 'nonmarking)
-                  (aset v 1 elt))
-                 ((or (eq elt 'calendar)
-                      (eq elt 'date)
-                      (eq elt 'dayname))
-                  (aset v 2 elt))
-                 ((eq elt 'time)
-                  (aset v 3 elt))
-                 ((or (eq elt 'here)
-                      (eq elt 'region))
-                  (aset v 4 elt))))
-         (setq l (append v nil))))
-      (setq new (append new (list l))))
-    new)
-  "List of all argument lists for Todos insertion commands.")
+(defun todos-done-string-matcher (lim)
+  "Search for Todos done header within LIM for font-locking."
+  (re-search-forward (concat todos-done-string-start
+                     "[^][]+]")
+                    lim t))
 
-(defun todos-insertion-command-name (arglist)
-  "Generate Todos insertion command name from ARGLIST."
-  (replace-regexp-in-string
-   "-\\_>" ""
-   (replace-regexp-in-string
-    "-+" "-"
-    (concat "todos-item-insert-"
-           (mapconcat (lambda (e) (if e (symbol-name e))) arglist "-")))))
+(defun todos-comment-string-matcher (lim)
+  "Search for Todos done comment within LIM for font-locking."
+  (re-search-forward (concat "\\[\\(?1:" todos-comment-string "\\):")
+                    lim t))
 
-(defvar todos-insertion-commands-names
-  (mapcar (lambda (l)
-          (todos-insertion-command-name l))
-         todos-insertion-commands-args)
-  "List of names of Todos insertion commands.")
+;; (defun todos-category-string-matcher (lim)
+;;   "Search for Todos category name within LIM for font-locking.
+;; This is for fontifying category names appearing in Todos filter
+;; mode."
+;;   (if (eq major-mode 'todos-filter-items-mode)
+;;       (re-search-forward
+;;        (concat "^\\(?:" todos-date-string-start "\\)?" todos-date-pattern
+;;                    "\\(?: " diary-time-regexp "\\)?\\(?:"
+;;                    (regexp-quote todos-nondiary-end) "\\)? \\(?1:\\[.+\\]\\)")
+;;        lim t)))
+
+(defun todos-category-string-matcher-1 (lim)
+  "Search for Todos category name within LIM for font-locking.
+This is for fontifying category names appearing in Todos filter
+mode following done items."
+  (if (eq major-mode 'todos-filter-items-mode)
+      (re-search-forward (concat todos-done-string-start todos-date-pattern
+                                "\\(?: " diary-time-regexp
+                                ;; Use non-greedy operator to prevent
+                                ;; capturing possible following non-diary
+                                ;; date string.
+                                "\\)?] \\(?1:\\[.+?\\]\\)")
+                        lim t)))
+
+(defun todos-category-string-matcher-2 (lim)
+  "Search for Todos category name within LIM for font-locking.
+This is for fontifying category names appearing in Todos filter
+mode following todo (not done) items."
+  (if (eq major-mode 'todos-filter-items-mode)
+      (re-search-forward (concat todos-date-string-start todos-date-pattern
+                                "\\(?: " diary-time-regexp "\\)?\\(?:"
+                                (regexp-quote todos-nondiary-end)
+                                "\\)? \\(?1:\\[.+\\]\\)")
+                        lim t)))
 
-(defmacro todos-define-insertion-command (&rest args)
-  (let ((name (intern (todos-insertion-command-name args)))
-       (arg0 (nth 0 args))
-       (arg1 (nth 1 args))
-       (arg2 (nth 2 args))
-       (arg3 (nth 3 args))
-       (arg4 (nth 4 args)))
-    `(defun ,name (&optional arg)
-       "Todos item insertion command."
-       (interactive)
-       (todos-insert-item arg ',arg0 ',arg1 ',arg2 ',arg3 ',arg4))))
+(defun todos-category-number (cat)
+  "Return the number of category CAT in this Todos file.
+The buffer-local variable `todos-category-number' holds this
+number as its value."
+  (let ((categories (mapcar 'car todos-categories)))
+    (setq todos-category-number
+         ;; Increment by one, so that the highest priority category in Todos
+         ;; Categories mode is numbered one rather than zero.
+         (1+ (- (length categories)
+                (length (member cat categories)))))))
 
-(defvar todos-insertion-commands
-  (mapcar (lambda (c)
-         (eval `(todos-define-insertion-command ,@c)))
-       todos-insertion-commands-args)
-  "List of Todos insertion commands.")
+(defun todos-current-category ()
+  "Return the name of the current category."
+  (car (nth (1- todos-category-number) todos-categories)))
 
-(defvar todos-insertion-commands-arg-key-list
-  '(("diary" "y" "yy")
-    ("nonmarking" "k" "kk")
-    ("calendar" "c" "cc")
-    ("date" "d" "dd")
-    ("dayname" "n" "nn")
-    ("time" "t" "tt")
-    ("here" "h" "h")
-    ("region" "r" "r"))
-  "")    
+(defconst todos-category-beg "--==-- "
+  "String marking beginning of category (inserted with its name).")
 
-(defun todos-insertion-key-bindings (map)
-  ""
-  (dolist (c todos-insertion-commands)
-    (let* ((key "")
-          (cname (symbol-name c)))
-      ;; (if (string-match "diary\\_>" cname) (setq key (concat key "yy")))
-      ;; (if (string-match "diary.+" cname) (setq key (concat key "y")))
-      ;; (if (string-match "nonmarking\\_>" cname) (setq key (concat key "kk")))
-      ;; (if (string-match "nonmarking.+" cname) (setq key (concat key "k")))
-      ;; (if (string-match "calendar\\_>" cname) (setq key (concat key "cc")))
-      ;; (if (string-match "calendar.+" cname) (setq key (concat key "c")))
-      ;; (if (string-match "date\\_>" cname) (setq key (concat key "dd")))
-      ;; (if (string-match "date.+" cname) (setq key (concat key "d")))
-      ;; (if (string-match "dayname\\_>" cname) (setq key (concat key "nn")))
-      ;; (if (string-match "dayname.+" cname) (setq key (concat key "n")))
-      ;; (if (string-match "time\\_>" cname) (setq key (concat key "tt")))
-      ;; (if (string-match "time.+" cname) (setq key (concat key "t")))
-      ;; (if (string-match "here" cname) (setq key (concat key "h")))
-      ;; (if (string-match "region" cname) (setq key (concat key "r")))
-      (mapc (lambda (l)
-             (let ((arg (nth 0 l))
-                   (key1 (nth 1 l))
-                   (key2 (nth 2 l)))
-               (if (string-match (concat (regexp-quote arg) "\\_>") cname)
-                   (setq key (concat key key2)))
-               (if (string-match (concat (regexp-quote arg) ".+") cname)
-                   (setq key (concat key key1)))))
-           todos-insertion-commands-arg-key-list)
-      (if (string-match (concat (regexp-quote "todos-item-insert") "\\_>") cname)
-         (setq key (concat key "i")))
-      (define-key map key c))))
-
-(defvar todos-insertion-map
-  (let ((map (make-keymap)))
-    (todos-insertion-key-bindings map)
-    map)
-  "Keymap for Todos mode insertion commands.")
-
-(defvar todos-mode-map
-  (let ((map (make-keymap)))
-    ;; Don't suppress digit keys, so they can supply prefix arguments.
-    (suppress-keymap map)
-    ;; display commands
-    (define-key map "Cd" 'todos-display-categories) ;FIXME: Cs todos-show-categories?
-    ;; (define-key map "" 'todos-display-categories-alphabetically)
-    (define-key map "H" 'todos-highlight-item)
-    (define-key map "N" 'todos-toggle-item-numbering)
-    (define-key map "D" 'todos-toggle-display-date-time)
-    (define-key map "*" 'todos-toggle-mark-item)
-    (define-key map "C*" 'todos-mark-category)
-    (define-key map "Cu" 'todos-unmark-category)
-    (define-key map "P" 'todos-print)
-    ;; (define-key map "" 'todos-print-to-file)
-    (define-key map "v" 'todos-toggle-view-done-items)
-    (define-key map "V" 'todos-toggle-show-done-only)
-    (define-key map "Av" 'todos-view-archived-items)
-    (define-key map "As" 'todos-show-archive)
-    (define-key map "Ac" 'todos-choose-archive)
-    (define-key map "Y" 'todos-diary-items)
-    ;; (define-key map "" 'todos-update-merged-files)
-    ;; (define-key map "" 'todos-set-top-priorities)
-    (define-key map "Ftt" 'todos-top-priorities)
-    (define-key map "Ftm" 'todos-merged-top-priorities)
-    (define-key map "Fdd" 'todos-diary-items)
-    (define-key map "Fdm" 'todos-merged-diary-items)
-    (define-key map "Frr" 'todos-regexp-items)
-    (define-key map "Frm" 'todos-merged-regexp-items)
-    (define-key map "Fcc" 'todos-custom-items)
-    (define-key map "Fcm" 'todos-merged-custom-items)
-    ;; (define-key map "" 'todos-save-top-priorities)
-    ;; navigation commands
-    (define-key map "f" 'todos-forward-category)
-    (define-key map "b" 'todos-backward-category)
-    (define-key map "j" 'todos-jump-to-category)
-    (define-key map "J" 'todos-jump-to-category-other-file)
-    (define-key map "n" 'todos-forward-item)
-    (define-key map "p" 'todos-backward-item)
-    (define-key map "S" 'todos-search)
-    (define-key map "X" 'todos-clear-matches)
-    ;; editing commands
-    (define-key map "Fa" 'todos-add-file)
-    ;; (define-key map "" 'todos-change-default-file)
-    (define-key map "Ca" 'todos-add-category)
-    (define-key map "Cr" 'todos-rename-category)
-    (define-key map "Cg" 'todos-merge-category)
-    ;; (define-key map "" 'todos-merge-categories)
-    (define-key map "Cm" 'todos-move-category)
-    (define-key map "Ck" 'todos-delete-category)
-    (define-key map "d" 'todos-item-done)
-    (define-key map "ee" 'todos-edit-item)
-    (define-key map "em" 'todos-edit-multiline)
-    (define-key map "eh" 'todos-edit-item-header)
-    (define-key map "ed" 'todos-edit-item-date)
-    (define-key map "ey" 'todos-edit-item-date-is-today)
-    (define-key map "et" 'todos-edit-item-time)
-    (define-key map "ec" 'todos-comment-done-item) ;FIXME: or just "c"?
-    (define-key map "i" todos-insertion-map)
-    (define-key map "k" 'todos-delete-item)
-    (define-key map "m" 'todos-move-item)
-    (define-key map "M" 'todos-move-item-to-file)
-    ;; FIXME: This prevents `-' from being used in a numerical prefix argument
-    ;; without typing C-u
-    (define-key map "-" 'todos-raise-item-priority)
-    (define-key map "r" 'todos-raise-item-priority)
-    (define-key map "+" 'todos-lower-item-priority)
-    (define-key map "l" 'todos-lower-item-priority)
-    (define-key map "#" 'todos-set-item-priority)
-    (define-key map "u" 'todos-item-undo)
-    (define-key map "Ad" 'todos-archive-done-item-or-items)  ;FIXME
-    (define-key map "AD" 'todos-archive-category-done-items) ;FIXME
-    ;; (define-key map "" 'todos-unarchive-items)
-    ;; (define-key map "" 'todos-unarchive-category)
-    (define-key map "y" 'todos-toggle-diary-inclusion)
-    ;; (define-key map "" 'todos-toggle-diary-inclusion)
-    ;; (define-key map "" 'todos-toggle-item-diary-nonmarking)
-    ;; (define-key map "" 'todos-toggle-diary-nonmarking)
-    (define-key map "s" 'todos-save)
-    (define-key map "q" 'todos-quit)
-    (define-key map [remap newline] 'newline-and-indent)
-    map)
-  "Todos mode keymap.")
-
-(easy-menu-define
-  todos-menu todos-mode-map "Todos Menu"
-  '("Todos"
-    ("Navigation"
-     ["Next Item"            todos-forward-item t]
-     ["Previous Item"        todos-backward-item t]
-     "---"
-     ["Next Category"        todos-forward-category t]
-     ["Previous Category"    todos-backward-category t]
-     ["Jump to Category"     todos-jump-to-category t]
-     ["Jump to Category in Other File" todos-jump-to-category-other-file t]
-     "---"
-     ["Search Todos File"    todos-search t]
-     ["Clear Highlighting on Search Matches" todos-category-done t])
-    ("Display"
-     ["List Current Categories" todos-display-categories t]
-     ;; ["List Categories Alphabetically" todos-display-categories-alphabetically t]
-     ["Turn Item Highlighting on/off" todos-highlight-item t]
-     ["Turn Item Numbering on/off" todos-toggle-item-numbering t]
-     ["Turn Item Time Stamp on/off" todos-toggle-display-date-time t]
-     ["View/Hide Done Items" todos-toggle-view-done-items t]
-     "---"
-     ["View Diary Items" todos-diary-items t]
-     ["View Top Priority Items" todos-top-priorities t]
-     ["View Merged Top Priority Items" todos-merged-top-priorities t]
-     "---"
-     ["View Archive" todos-view-archive t]
-     ["Print Category"     todos-print t]) ;FIXME
-    ("Editing"
-     ["Insert New Item"      todos-insert-item t]
-     ["Insert Item Here"     todos-insert-item-here t]
-     ("More Insertion Commands")
-     ["Edit Item"            todos-edit-item t]
-     ["Edit Multiline Item"  todos-edit-multiline t]
-     ["Edit Item Header"     todos-edit-item-header t]
-     ["Edit Item Date"       todos-edit-item-date t]
-     ["Edit Item Time"       todos-edit-item-time t]
-     "---"
-     ["Lower Item Priority"  todos-lower-item-priority t]
-     ["Raise Item Priority"  todos-raise-item-priority t]
-     ["Set Item Priority" todos-set-item-priority t]
-     ["Move (Recategorize) Item" todos-move-item t]
-     ["Delete Item"          todos-delete-item t]
-     ["Undo Done Item" todos-item-undo t]
-     ["Mark/Unmark Item for Diary" todos-toggle-item-diary-inclusion t]
-     ["Mark/Unmark Items for Diary" todos-toggle-diary-inclusion t]
-     ["Mark & Hide Done Item" todos-item-done t]
-     ["Archive Done Items" todos-archive-category-done-items t] ;FIXME
-     "---"
-     ["Add New Todos File" todos-add-file t]
-     ["Add New Category" todos-add-category t]
-     ["Delete Current Category" todos-delete-category t]
-     ["Rename Current Category" todos-rename-category t]
-     "---"
-     ["Save Todos File"      todos-save t]
-     ["Save Top Priorities"  todos-save-top-priorities t])
-    "---"
-    ["Quit"                 todos-quit t]
-    ))
-
-(defvar todos-archive-mode-map
-  (let ((map (make-sparse-keymap)))
-    (suppress-keymap map t)
-    ;; navigation commands
-    (define-key map "f" 'todos-forward-category)
-    (define-key map "b" 'todos-backward-category)
-    (define-key map "j" 'todos-jump-to-category)
-    (define-key map "n" 'todos-forward-item)
-    (define-key map "p" 'todos-backward-item)
-    ;; display commands
-    (define-key map "C" 'todos-display-categories)
-    (define-key map "H" 'todos-highlight-item)
-    (define-key map "N" 'todos-toggle-item-numbering)
-    ;; (define-key map "" 'todos-toggle-display-date-time)
-    (define-key map "P" 'todos-print)
-    (define-key map "q" 'todos-quit)
-    (define-key map "s" 'todos-save)
-    (define-key map "S" 'todos-search)
-    (define-key map "t" 'todos-show)   ;FIXME: should show same category
-    ;; (define-key map "u" 'todos-unarchive-item)
-    (define-key map "U" 'todos-unarchive-category)
-    map)
-  "Todos Archive mode keymap.")
+(defconst todos-category-done "==--== DONE "
+  "String marking beginning of category's done items.")
 
-(defvar todos-edit-mode-map
-  (let ((map (make-sparse-keymap)))
-    (define-key map "\C-x\C-q" 'todos-edit-quit)
-    (define-key map [remap newline] 'newline-and-indent)
-    map)
-  "Todos Edit mode keymap.")
+(defun todos-category-select ()
+  "Display the current category correctly."
+  (let ((name (todos-current-category))
+       cat-begin cat-end done-start done-sep-start done-end)
+    (widen)
+    (goto-char (point-min))
+    (re-search-forward
+     (concat "^" (regexp-quote (concat todos-category-beg name)) "$") nil t)
+    (setq cat-begin (1+ (line-end-position)))
+    (setq cat-end (if (re-search-forward
+                      (concat "^" (regexp-quote todos-category-beg)) nil t)
+                     (match-beginning 0)
+                   (point-max)))
+    (setq mode-line-buffer-identification
+         (funcall todos-mode-line-function name))
+    (narrow-to-region cat-begin cat-end)
+    (todos-prefix-overlays)
+    (goto-char (point-min))
+    (if (re-search-forward (concat "\n\\(" (regexp-quote todos-category-done)
+                                  "\\)") nil t)
+       (progn
+         (setq done-start (match-beginning 0))
+         (setq done-sep-start (match-beginning 1))
+         (setq done-end (match-end 0)))
+      (error "Category %s is missing todos-category-done string" name))
+    (if todos-show-done-only
+       (narrow-to-region (1+ done-end) (point-max))
+      (when (and todos-show-with-done
+                (re-search-forward todos-done-string-start nil t))
+       ;; Now we want to see the done items, so reset displayed end to end of
+       ;; done items.
+       (setq done-start cat-end)
+       ;; Make display overlay for done items separator string, unless there
+       ;; already is one.
+       (let* ((done-sep todos-done-separator)
+              (ovs (overlays-at done-sep-start))
+              ov-sep)
+         (unless (and ovs (string= (overlay-get (car ovs) 'display) done-sep))
+           (setq ov-sep (make-overlay done-sep-start done-end))
+           (overlay-put ov-sep 'display done-sep))))
+      (narrow-to-region (point-min) done-start)
+      ;; Loading this from todos-mode, or adding it to the mode hook, causes
+      ;; Emacs to hang in todos-item-start, at looking-at.
+      (when todos-highlight-item
+       (require 'hl-line)
+       (hl-line-mode 1)))))
 
-(defvar todos-categories-mode-map
-  (let ((map (make-sparse-keymap)))
-    (suppress-keymap map t)
-    ;; (define-key map "a" 'todos-display-categories-alphabetically)
-    (define-key map "c" 'todos-display-categories)
-    (define-key map "+" 'todos-lower-category)
-    (define-key map "-" 'todos-raise-category)
-    (define-key map "n" 'forward-button)
-    (define-key map "p" 'backward-button)
-    (define-key map [tab] 'forward-button)
-    (define-key map [backtab] 'backward-button)
-    (define-key map "q" 'todos-quit)
-    ;; (define-key map "A" 'todos-add-category)
-    ;; (define-key map "D" 'todos-delete-category)
-    ;; (define-key map "R" 'todos-rename-category)
-    map)
-  "Todos Categories mode keymap.")
+(defun todos-get-count (type &optional category)
+  "Return count of TYPE items in CATEGORY.
+If CATEGORY is nil, default to the current category."
+  (let* ((cat (or category (todos-current-category)))
+        (counts (cdr (assoc cat todos-categories)))
+        (idx (cond ((eq type 'todo) 0)
+                   ((eq type 'diary) 1)
+                   ((eq type 'done) 2)
+                   ((eq type 'archived) 3))))
+    (aref counts idx)))
 
-(defvar todos-filter-items-mode-map
-  (let ((map (make-keymap)))
-    (suppress-keymap map t)
-    ;; navigation commands
-    (define-key map "j" 'todos-jump-to-category)
-    (define-key map "n" 'todos-forward-item)
-    (define-key map "p" 'todos-backward-item)
-    ;; (define-key map "S" 'todos-search)
-    ;; display commands
-    (define-key map "C" 'todos-display-categories)
-    ;; (define-key map "" 'todos-display-categories-alphabetically)
-    (define-key map "H" 'todos-highlight-item)
-    (define-key map "N" 'todos-toggle-item-numbering)
-    ;; (define-key map "" 'todos-toggle-display-date-time)
-    (define-key map "P" 'todos-print)
-    (define-key map "q" 'todos-quit)
-    (define-key map "s" 'todos-save)
-    (define-key map "V" 'todos-view-archive)
-    (define-key map "v" 'todos-toggle-view-done-items)
-    (define-key map "Y" 'todos-diary-items)
-    ;; (define-key map "S" 'todos-save-top-priorities)
-    ;; editing commands
-    (define-key map "l" 'todos-lower-item-priority)
-    (define-key map "r" 'todos-raise-item-priority)
-    (define-key map "#" 'todos-set-item-priority)
-    map)
-  "Todos Top Priorities mode keymap.")
+(defun todos-set-count (type increment &optional category)
+  "Increment count of TYPE items in CATEGORY by INCREMENT.
+If CATEGORY is nil, default to the current category."
+  (let* ((cat (or category (todos-current-category)))
+        (counts (cdr (assoc cat todos-categories)))
+        (idx (cond ((eq type 'todo) 0)
+                   ((eq type 'diary) 1)
+                   ((eq type 'done) 2)
+                   ((eq type 'archived) 3))))
+    (aset counts idx (+ increment (aref counts idx)))))
 
-;; FIXME: remove when part of Emacs
-(add-to-list 'auto-mode-alist '("\\.todo\\'" . todos-mode))
-(add-to-list 'auto-mode-alist '("\\.toda\\'" . todos-archive-mode))
+(defun todos-set-categories ()
+  "Set `todos-categories' from the sexp at the top of the file."
+  ;; New archive files created by `todos-move-category' are empty, which would
+  ;; make the sexp test fail and raise an error, so in this case we skip it.
+  (unless (zerop (buffer-size))
+    (save-excursion
+      (save-restriction
+       (widen)
+       (goto-char (point-min))
+       ;; todos-truncate-categories-list needs non-nil todos-categories.
+       (setq todos-categories-full
+             (if (looking-at "\(\(\"")
+                 (read (buffer-substring-no-properties
+                        (line-beginning-position)
+                        (line-end-position)))
+               (error "Invalid or missing todos-categories sexp"))
+             todos-categories todos-categories-full)))
+    (if (and todos-ignore-archived-categories
+            (eq major-mode 'todos-mode))
+       (todos-truncate-categories-list)
+      todos-categories-full)))
 
-(defun todos-modes-set-1 ()
-  ""
-  (set (make-local-variable 'font-lock-defaults) '(todos-font-lock-keywords t))
-  (set (make-local-variable 'indent-line-function) 'todos-indent)
-  (when todos-wrap-lines (funcall todos-line-wrapping-function))
-)
+(defun todos-update-categories-sexp ()
+  "Update the `todos-categories' sexp at the top of the file."
+  (let (buffer-read-only)
+    (save-excursion
+      (save-restriction
+       (widen)
+       (goto-char (point-min))
+       (if (looking-at (concat "^" (regexp-quote todos-category-beg)))
+           (progn (newline) (goto-char (point-min)))
+         ;; With empty buffer (e.g. with new archive in
+         ;; `todos-move-category') `kill-line' signals end of buffer.
+         (kill-region (line-beginning-position) (line-end-position)))
+       ;; todos-categories-full is nil on adding first category.
+       (prin1 (or todos-categories-full todos-categories)
+              (current-buffer))))))
 
-(defun todos-modes-set-2 ()
-  ""
-  (add-to-invisibility-spec 'todos)
-  (setq buffer-read-only t)
-  (set (make-local-variable 'hl-line-range-function)
-       (lambda() (when (todos-item-end)
-                  (cons (todos-item-start) (todos-item-end)))))
-)
-
-;; Autoloading isn't needed if files are identified by auto-mode-alist
-;; ;; As calendar reads included Todos file before todos-mode is loaded.
-;; ;;;###autoload
-(define-derived-mode todos-mode nil "Todos" () ;FIXME: derive from special-mode?
-  "Major mode for displaying, navigating and editing Todo lists.
+(defun todos-make-categories-list (&optional force)
+  "Return an alist of Todos categories and their item counts.
+With non-nil argument FORCE parse the entire file to build the
+list; otherwise, get the value by reading the sexp at the top of
+the file."
+  (setq todos-categories nil)
+  (save-excursion
+    (save-restriction
+      (widen)
+      (goto-char (point-min))
+      (let (counts cat archive)
+       (when buffer-file-name   ; Don't check with `todos-convert-legacy-files'.
+         ;; FIXME: can todos-archives be too old here?
+         (unless (member buffer-file-name (funcall todos-files-function t))
+           (setq archive (concat (file-name-sans-extension
+                                  todos-current-todos-file) ".toda"))))
+       (while (not (eobp))
+         (cond ((looking-at (concat (regexp-quote todos-category-beg)
+                                    "\\(.*\\)\n"))
+                (setq cat (match-string-no-properties 1))
+                ;; Counts for each category: [todo diary done archive]
+                (setq counts (make-vector 4 0))
+                (setq todos-categories
+                      (append todos-categories (list (cons cat counts))))
+                ;; todos-archives may be too old here (e.g. during
+                ;; todos-move-category).
+                (when (member archive (funcall todos-files-function t))
+                  (let ((archive-count 0))
+                    (with-current-buffer (find-file-noselect archive)
+                      (widen)
+                      (goto-char (point-min))
+                      (when (re-search-forward
+                             (concat (regexp-quote todos-category-beg) cat)
+                             (point-max) t)
+                        (forward-line)
+                        (while (not (or (looking-at
+                                         (concat
+                                          (regexp-quote todos-category-beg)
+                                          "\\(.*\\)\n"))
+                                        (eobp)))
+                          (when (looking-at todos-done-string-start)
+                            (setq archive-count (1+ archive-count)))
+                          (forward-line))))
+                    (todos-set-count 'archived archive-count cat))))
+               ((looking-at todos-done-string-start)
+                (todos-set-count 'done 1 cat))
+               ((looking-at (concat "^\\("
+                                    (regexp-quote diary-nonmarking-symbol)
+                                    "\\)?" todos-date-pattern))
+                (todos-set-count 'diary 1 cat)
+                (todos-set-count 'todo 1 cat))
+               ((looking-at (concat todos-date-string-start todos-date-pattern))
+                (todos-set-count 'todo 1 cat))
+               ;; If first line is todos-categories list, use it and end loop
+               ;; -- unless FORCEd to scan whole file.
+               ((bobp)
+                (unless force
+                  (setq todos-categories (read (buffer-substring-no-properties
+                                                (line-beginning-position)
+                                                (line-end-position))))
+                  (goto-char (1- (point-max))))))
+         (forward-line)))))
+  todos-categories)
 
-\\{todos-mode-map}"
-  (easy-menu-add todos-menu)
-  (todos-modes-set-1)
-  (todos-modes-set-2)
-  (when (member (file-truename (buffer-file-name))
-               (funcall todos-files-function))
-    (set (make-local-variable 'todos-current-todos-file)
-        (file-truename (buffer-file-name))))
-  (set (make-local-variable 'todos-categories-full) nil)
-  ;; todos-set-categories sets todos-categories-full.
-  (set (make-local-variable 'todos-categories) (todos-set-categories))
-  (set (make-local-variable 'todos-first-visit) t)
-  (set (make-local-variable 'todos-category-number) 1) ;0)
-  (set (make-local-variable 'todos-show-done-only) nil)
-  (set (make-local-variable 'todos-categories-with-marks) nil)
-  (when todos-show-current-file
-    (add-hook 'pre-command-hook 'todos-show-current-file nil t))
-  (add-hook 'post-command-hook 'todos-after-find-file nil t)
-  (add-hook 'kill-buffer-hook 'todos-reset-global-current-todos-file nil t))
+(defun todos-truncate-categories-list ()
+  "Return a truncated alist of Todos categories plus item counts.
+Categories containing only archived items are omitted.  This list
+is used in Todos mode when `todos-ignore-archived-categories' is
+non-nil."
+  (let (cats)
+    (dolist (catcons todos-categories-full cats)
+      (let ((cat (car catcons)))
+       (setq cats
+             (append cats
+                     (unless (and (zerop (todos-get-count 'todo cat))
+                                  (zerop (todos-get-count 'done cat))
+                                  (not (zerop (todos-get-count 'archived cat))))
+                       (list catcons))))))))
 
-;; FIXME:
-(defun todos-unload-hook ()
-  ""
-  (remove-hook 'pre-command-hook 'todos-show-current-file t)
-  (remove-hook 'post-command-hook 'todos-after-find-file t)
-  (remove-hook 'kill-buffer-hook 'todos-reset-global-current-todos-file t))
+(defun todos-check-format ()
+  "Signal an error if the current Todos file is ill-formatted.
+Otherwise return t.  The error message gives the line number
+where the invalid formatting was found."
+  (save-excursion
+    (save-restriction
+      (widen)
+      (goto-char (point-min))
+      ;; Check for `todos-categories' sexp as the first line
+      (let ((cats (prin1-to-string (or todos-categories-full todos-categories))))
+       (unless (looking-at (regexp-quote cats))
+         (error "Invalid or missing todos-categories sexp")))
+      (forward-line)
+      (let ((legit (concat "\\(^" (regexp-quote todos-category-beg) "\\)"
+                          "\\|\\(" todos-date-string-start todos-date-pattern "\\)"
+                          "\\|\\(^[ \t]+[^ \t]*\\)"
+                          "\\|^$"
+                          "\\|\\(^" (regexp-quote todos-category-done) "\\)"
+                          "\\|\\(" todos-done-string-start "\\)")))
+       (while (not (eobp))
+         (unless (looking-at legit)
+           (error "Illegitimate Todos file format at line %d"
+                  (line-number-at-pos (point))))
+         (forward-line)))))
+  ;; (message "This Todos file is well-formatted.")
+  t)
 
-(define-derived-mode todos-archive-mode nil "Todos-Arch" ()
-  "Major mode for archived Todos categories.
+(defun todos-repair-categories-sexp ()
+  "Repair corrupt Todos categories sexp."
+  (interactive)
+  (let ((todos-categories-full (todos-make-categories-list t)))
+    (todos-update-categories-sexp)))
 
-\\{todos-archive-mode-map}"
-  (todos-modes-set-1)
-  (todos-modes-set-2)
-  (set (make-local-variable 'todos-show-done-only) t)
-  (set (make-local-variable 'todos-current-todos-file)
-       (file-truename (buffer-file-name)))
-  (set (make-local-variable 'todos-categories) (todos-set-categories))
-  (set (make-local-variable 'todos-category-number) 1) ; 0)
-  (add-hook 'post-command-hook 'todos-after-find-file nil t))
+(defvar todos-item-start (concat "\\(" todos-date-string-start "\\|"
+                                todos-done-string-start "\\)"
+                                todos-date-pattern)
+  "String identifying start of a Todos item.")
 
-;; FIXME: return to Todos or Archive mode
-(define-derived-mode todos-raw-mode nil "Todos Raw" ()
-  "Emergency repair mode for Todos files."
-  (when (member major-mode '(todos-mode todos-archive-mode))
-    (setq buffer-read-only nil)
-    (set (make-local-variable 'font-lock-defaults) '(todos-font-lock-keywords t))
-    (widen)
-    ;; FIXME: doesn't DTRT here
-    (todos-prefix-overlays)))
+(defun todos-item-start ()
+  "Move to start of current Todos item and return its position."
+  (unless (or
+          ;; Point is either on last item in this category or on the empty
+          ;; line between done and not done items.
+          (looking-at "^$")
+          ;; There are no done items in this category yet.
+          (looking-at (regexp-quote todos-category-beg)))
+    (goto-char (line-beginning-position))
+    (while (not (looking-at todos-item-start))
+      (forward-line -1))
+    (point)))
 
-(define-derived-mode todos-edit-mode nil "Todos-Ed" ()
-  "Major mode for editing multiline Todo items.
+(defun todos-item-end ()
+  "Move to end of current Todos item and return its position."
+  ;; Items cannot end with a blank line.
+  (unless (looking-at "^$")
+    (let ((done (todos-done-item-p)))
+      (todos-forward-item)
+      ;; Adjust if item is last unfinished one before displayed done items.
+      (when (and (not done) (todos-done-item-p))
+       (forward-line -1))
+      (backward-char))
+    (point)))
 
-\\{todos-edit-mode-map}"
-  (todos-modes-set-1))
+(defun todos-item-string ()
+  "Return bare text of current item as a string."
+  (let ((opoint (point))
+       (start (todos-item-start))
+       (end (todos-item-end)))
+    (goto-char opoint)
+    (and start end (buffer-substring-no-properties start end))))
 
-(define-derived-mode todos-categories-mode nil "Todos-Cats" ()
-  "Major mode for displaying and editing Todos categories.
+(defun todos-remove-item ()
+  "Internal function called in editing, deleting or moving items."
+  (let* ((beg (todos-item-start))
+        (end (progn (todos-item-end) (1+ (point))))
+        (ovs (overlays-in beg beg)))
+    ;; There can be both prefix/number and mark overlays.
+    (while ovs (delete-overlay (car ovs)) (pop ovs))
+    (delete-region beg end)))
 
-\\{todos-categories-mode-map}"
-  (set (make-local-variable 'todos-current-todos-file)
-       todos-global-current-todos-file)
-  (let ((cats (with-current-buffer (get-file-buffer todos-current-todos-file)
-               (if todos-ignore-archived-categories
-                   todos-categories-full
-                 (todos-set-categories)))))
-    (set (make-local-variable 'todos-categories) cats)))
+(defun todos-diary-item-p ()
+  "Return non-nil if item at point is marked for diary inclusion."
+  (save-excursion
+    (todos-item-start)
+    ;; (looking-at todos-date-pattern)))
+    (not (looking-at (regexp-quote todos-nondiary-start)))))
 
-(define-derived-mode todos-filter-items-mode nil "Todos-Top" ()
-  "Mode for displaying and reprioritizing top priority Todos.
+(defun todos-done-item-p ()
+  "Return non-nil if item at point is a done item."
+  (save-excursion
+    (todos-item-start)
+    (looking-at todos-done-string-start)))
 
-\\{todos-filter-items-mode-map}"
-  (todos-modes-set-1)
-  (todos-modes-set-2))
+(defvar todos-item-mark (propertize (if (equal todos-prefix "*") "@" "*")
+                                   'face 'todos-mark)
+  "String used to mark items.")
 
-;; FIXME: need this?
-(defun todos-save ()
-  "Save the current Todos file."
-  (interactive)
-  ;; (todos-update-categories-sexp)
-  (save-buffer)
-  ;; (if todos-save-top-priorities-too (todos-save-top-priorities))
-  )
+(defun todos-marked-item-p ()
+  "If this item is marked, return mark overlay."
+  (let ((ovs (overlays-in (line-beginning-position) (line-beginning-position)))
+       (mark todos-item-mark)
+       ov marked)
+    (catch 'stop
+      (while ovs
+       (setq ov (pop ovs))
+       (and (equal (overlay-get ov 'before-string) mark)
+            (throw 'stop (setq marked t)))))
+    (when marked ov)))
 
-(defun todos-quit ()
-  "Exit the current Todos-related buffer.
-Depending on the specific mode, this either kills and the buffer
-or buries it."
-  (interactive)
-  (cond ((eq major-mode 'todos-categories-mode)
-        (kill-buffer)
-        (setq todos-descending-counts nil)
-        (todos-show))
-       ((eq major-mode 'todos-filter-items-mode)
-        (kill-buffer)
-        (todos-show))
-       ((member major-mode (list 'todos-mode 'todos-archive-mode))
-        (todos-save)
-        (bury-buffer))))
+(defun todos-insert-with-overlays (item)
+  "Insert ITEM at point and update prefix/priority number overlays."
+  (todos-item-start)
+  (insert item "\n")
+  (todos-backward-item)
+  (todos-prefix-overlays))
 
-;; ---------------------------------------------------------------------------
-;;; Commands
+(defun todos-prefix-overlays ()
+  "Put before-string overlay in front of this category's items.
+The overlay's value is the string `todos-prefix' or with non-nil
+`todos-number-prefix' an integer in the sequence from 1 to the
+number of todo or done items in the category indicating the
+item's priority.  Todo and done items are numbered independently
+of each other."
+  (when (or todos-number-prefix
+           (not (string-match "^[[:space:]]*$" todos-prefix)))
+    (let ((prefix (propertize (concat todos-prefix " ")
+                             'face 'todos-prefix-string))
+         (num 0))
+      (save-excursion
+       (goto-char (point-min))
+       (while (not (eobp))
+         (when (or (todos-date-string-matcher (line-end-position))
+                   (todos-done-string-matcher (line-end-position)))
+           (goto-char (match-beginning 0))
+           (when todos-number-prefix
+             (setq num (1+ num))
+             ;; Reset number to 1 for first done item.
+             (when (and (looking-at todos-done-string-start)
+                        (looking-back (concat "^"
+                                              (regexp-quote todos-category-done)
+                                              "\n")))
+               (setq num 1))
+             (setq prefix (propertize (concat (number-to-string num) " ")
+                                      'face 'todos-prefix-string)))
+           (let ((ovs (overlays-in (point) (point)))
+                 marked ov-pref)
+             (if ovs
+                 (dolist (ov ovs)
+                   (let ((val (overlay-get ov 'before-string)))
+                     (if (equal val "*")
+                         (setq marked t)
+                       (setq ov-pref val)))))
+             (unless (equal ov-pref prefix)
+               ;; Why doesn't this work?
+               ;; (remove-overlays (point) (point) 'before-string)
+               (remove-overlays (point) (point))
+               (overlay-put (make-overlay (point) (point))
+                            'before-string prefix)
+               (and marked (overlay-put (make-overlay (point) (point))
+                                        'before-string todos-item-mark)))))
+         (forward-line))))))
 
-;;; Display
+(defun todos-read-file-name (prompt &optional archive mustmatch)
+  "Choose and return the name of a Todos file, prompting with PROMPT.
 
-;;;###autoload
-(defun todos-show (&optional solicit-file)
-  "Visit the current Todos file and display one of its categories.
+Show completions with TAB or SPC; the names are shown in short
+form but the absolute truename is returned.  With non-nil ARCHIVE
+return the absolute truename of a Todos archive file.  With non-nil
+MUSTMATCH the name of an existing file must be chosen;
+otherwise, a new file name is allowed."
+  (unless (file-exists-p todos-files-directory)
+    (make-directory todos-files-directory))
+  (let ((completion-ignore-case todos-completion-ignore-case)
+       (files (mapcar 'file-name-sans-extension
+                      (directory-files todos-files-directory nil
+                                       (if archive "\.toda$" "\.todo$"))))
+       (file ""))
+    (while (string= "" file)
+      (setq file (completing-read prompt files nil mustmatch))
+      (setq prompt "Enter a non-empty name (TAB for list of current files): "))
+    (setq file (concat todos-files-directory file
+                      (if archive ".toda" ".todo")))
+    (unless mustmatch
+      (when (not (member file todos-files))
+       (todos-validate-name file 'file)))
+    (file-truename file)))
 
-With non-nil prefix argument SOLICIT-FILE ask for file to visit.
-Otherwise, the first invocation of this command in a session
-visits `todos-default-todos-file' (creating it if it does not yet
-exist); subsequent invocations from outside of Todos mode revisit
-this file or, if user option `todos-show-current-file' is
-non-nil, whichever Todos file was visited last.
-
-The category displayed on initial invocation is the first member
-of `todos-categories' for the current Todos file, on subsequent
-invocations whichever category was displayed last.  If
-`todos-display-categories-first' is non-nil, then the first
-invocation of `todos-show' displays a clickable listing of the
-categories in the current Todos file."
-  (interactive "P")
-  (let ((file (cond (solicit-file
-                    (if (funcall todos-files-function)
-                        (todos-read-file-name "Select a Todos file to visit: "
-                                              nil t)
-                      (error "There are no Todos files")))
-                   ((eq major-mode 'todos-archive-mode)
-                    ;; FIXME: should it visit same category?
-                    (concat (file-name-sans-extension todos-current-todos-file)
-                            ".todo"))
-                   (t
-                    (or todos-current-todos-file
-                        (and todos-show-current-file
-                             todos-global-current-todos-file)
-                        todos-default-todos-file
-                        (todos-add-file))))))
-    (if (and todos-first-visit todos-display-categories-first)
-       (todos-display-categories)
-      (set-window-buffer (selected-window)
-                        (set-buffer (find-file-noselect file)))
-      ;; If no Todos file exists, initialize one.
-      (if (zerop (buffer-size))
-         ;; Call with empty category name to get initial prompt.
-         (setq todos-category-number (todos-add-category "")))
-      (save-excursion (todos-category-select)))
-    (setq todos-first-visit nil)))
-
-(defun todos-toggle-item-numbering ()
-  ""
-  (interactive)
-  (todos-reset-prefix 'todos-number-prefix (not todos-number-prefix)))
-
-(defun todos-toggle-view-done-items ()
-  "Show hidden or hide visible done items in current category."
-  (interactive)
-  (save-excursion
-    (goto-char (point-min))
-    (let ((todos-show-with-done
-          (if (re-search-forward todos-done-string-start nil t)
-              nil
-            t))
-         (cat (todos-current-category)))
-      (todos-category-select)
-      (when (zerop (todos-get-count 'done cat))
-       (message "There are no done items in this category.")))))
-
-;; FIXME: should there be `todos-toggle-view-todo-items'?
-(defun todos-toggle-show-done-only ()
-  "Make category display done or back to todo items." ;FIXME
-  (interactive)
-  (setq todos-show-done-only (not todos-show-done-only))
-  (todos-category-select))
-
-(defun todos-view-archived-items ()
-  "Display the archived items of the current category.
-The buffer showing these items is in Todos Archive mode."
-  (interactive)
-  (let ((cat (todos-current-category)))
-    (if (zerop (todos-get-count 'archived cat))
-       (message "There are no archived items from this category.")
-      (let* ((tfile-base (file-name-sans-extension todos-current-todos-file))
-            (afile (concat tfile-base ".toda")))
-       (set-window-buffer (selected-window) (set-buffer
-                                             (find-file-noselect afile)))
-       (todos-category-number cat)
-       (todos-jump-to-category cat)))))
-
-(defun todos-show-archive (&optional ask)
-  "Visit the archive of the current Todos file, if it exists.
-With non-nil argument ASK prompt to choose an archive to visit;
-see `todos-choose-archive'.  The buffer showing the archive is in
-Todos Archive mode.  The first visit in a session displays the
-first category in the archive, subsequent visits return to the
-last category displayed."
-  (interactive)
-  (let* ((tfile-base (file-name-sans-extension todos-current-todos-file))
-        (afile (if ask
-                   (todos-read-file-name "Choose a Todos archive: " t t)
-                 (concat tfile-base ".toda"))))
-    (if (not (file-exists-p afile))
-       (message "There is currently no Todos archive for this file.")
-      (set-window-buffer (selected-window) (set-buffer
-                                           (find-file-noselect afile)))
-      (todos-category-select))))
-
-(defun todos-choose-archive ()
-  "Choose an archive and visit it."
-  (interactive)
-  (todos-show-archive t))
+(defun todos-read-category (prompt &optional mustmatch)
+  "Choose and return a category name, prompting with PROMPT.
+Show completions with TAB or SPC.  With non-nil MUSTMATCH the
+name must be that of an existing category; otherwise, a new
+category name is allowed, after checking its validity."
+  ;; Allow SPC to insert spaces, for adding new category names.
+  (let ((map minibuffer-local-completion-map))
+    (define-key map " " nil)
+    ;; 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)))
+          (completion-ignore-case todos-completion-ignore-case)
+          (cat (completing-read prompt todos-categories nil
+                                mustmatch nil history
+                                ;; Default for existing categories is the
+                                ;; current category.
+                                (if todos-categories
+                                    (todos-current-category)
+                                  ;; Trigger prompt for initial category
+                                  ""))))
+      (unless mustmatch
+       (when (not (assoc cat categories))
+               (todos-validate-name cat 'category)       
+         (if (y-or-n-p (format (concat "There is no category \"%s\" in "
+                                       "this file; add it? ") cat))
+             (todos-add-category cat)
+           (keyboard-quit))))
+      ;; Restore the original value of todos-categories.
+      (setq todos-categories categories)
+      cat)))
 
-(defun todos-highlight-item ()
-  "Highlight the todo item the cursor is on."
-  (interactive)
-  (if hl-line-mode ; todos-highlight-item
-      (hl-line-mode 0)
-    (hl-line-mode 1)))
+(defun todos-validate-name (name type)
+  "Prompt for new NAME for TYPE until it is valid, then return it.
+TYPE can be either a file or a category"
+  (let (prompt file cat shortname)
+    (while
+       (and (cond ((string= "" name)
+                   (setq prompt
+                         (cond ((eq type 'file)
+                                ;; FIXME: just todos-files ?
+                                (if (funcall (todos-files))
+                                    "Enter a non-empty file name: "
+                                  ;; Empty string passed by todos-show to
+                                  ;; prompt for initial Todos file.
+                                  (concat "Initial file name ["
+                                          todos-initial-file "]: ")))
+                               ((eq type 'category)
+                                (if todos-categories
+                                    "Enter a non-empty category name: "
+                                  ;; Empty string passed by todos-show to
+                                  ;; prompt for initial category of a new
+                                  ;; Todos file.
+                                  (concat "Initial category name ["
+                                          todos-initial-category "]: "))))))
+                  ((string-match "\\`\\s-+\\'" name)
+                   (setq prompt
+                         "Enter a name that does not contain only white space: "))
+                  ((and (eq type 'file) (member name todos-files))
+                   (setq prompt "Enter a non-existing file name: "))
+                  ((and (eq type 'category) (assoc name todos-categories))
+                   (setq prompt "Enter a non-existing category name: ")))
+            (setq name (if (or (and (eq type 'file) todos-files)
+                              (and (eq type 'category) todos-categories))
+                          (read-from-minibuffer prompt)
+                         ;; Offer default initial name.
+                         (read-string prompt nil nil
+                                      (cond ((eq type 'file)
+                                             todos-initial-file)
+                                            ((eq type 'category)
+                                             todos-initial-category))))))))
+  name)
+
+;; Adapted from calendar-read-date and calendar-date-string.
+(defun todos-read-date ()
+  "Prompt for Gregorian date and return it in the current format.
+Also accepts `*' as an unspecified month, day, or year."
+  (let* ((year (calendar-read
+               ;; FIXME: maybe better like monthname with RET for current month
+                "Year (>0 or * for any year): "
+                (lambda (x) (or (eq x '*) (> x 0)))
+                (number-to-string (calendar-extract-year
+                                  (calendar-current-date)))))
+         (month-array (vconcat calendar-month-name-array (vector "*")))
+        (abbrevs (vconcat calendar-month-abbrev-array (vector "*")))
+         (completion-ignore-case todos-completion-ignore-case)
+        (monthname (completing-read
+                    "Month name (RET for current month, * for any month): "
+                    (mapcar 'list (append month-array nil))
+                    nil t nil nil
+                    (calendar-month-name (calendar-extract-month
+                                          (calendar-current-date)) t)))
+         (month (cdr (assoc-string
+                     monthname (calendar-make-alist month-array nil nil
+                                                    abbrevs))))
+         (last (if (= month 13)
+                  31                   ; FIXME: what about shorter months?
+                (let ((yr (if (eq year '*)
+                              1999     ; FIXME: no Feb. 29
+                            year)))
+                  (calendar-last-day-of-month month yr))))
+        day dayname)
+    (while (if (numberp day) (or (< day 0) (< last day)) (not (eq day '*)))
+      (setq day (read-from-minibuffer
+                (format "Day (1-%d or RET for today or * for any day): " last)
+                nil nil t nil
+                (number-to-string
+                 (calendar-extract-day (calendar-current-date))))))
+    (setq year (if (eq year '*) (symbol-name '*) (number-to-string year)))
+    (setq day (if (eq day '*) (symbol-name '*) (number-to-string day)))
+    ;; FIXME: make abbreviation customizable
+    (setq monthname
+         (or (and (= month 13) "*")
+             (calendar-month-name (calendar-extract-month (list month day year))
+                                  t)))
+    (mapconcat 'eval calendar-date-display-form "")))
 
-(defun todos-toggle-display-date-time (&optional all)
-  "Hide or show date/time of todo items in current category.
-With non-nil prefix argument ALL do this in the whole file."
-  (interactive "P")
-  (save-excursion
-    (save-restriction
-      (goto-char (point-min))
-      (let ((ovs (overlays-in (point) (1+ (point))))
-           ov hidden)
-       (while ovs
-         (setq ov (pop ovs))
-         (if (equal (overlay-get ov 'display) "")
-             (setq ovs nil hidden t)))
-       (when all (widen) (goto-char (point-min)))
-       (if hidden
-           (remove-overlays (point-min) (point-max) 'display "")
-         (while (not (eobp))
-           (when (re-search-forward
-                  (concat todos-date-string-start todos-date-pattern
-                          "\\( " diary-time-regexp "\\)?"
-                          (regexp-quote todos-nondiary-end) "? ")
-                  nil t)
-             (unless (save-match-data (todos-done-item-p))
-               (setq ov (make-overlay (match-beginning 0) (match-end 0) nil t))
-               (overlay-put ov 'display "")))
-           (todos-forward-item)))))))
+(defun todos-read-dayname ()
+  "Choose name of a day of the week with completion and return it."
+  (let ((completion-ignore-case todos-completion-ignore-case))
+    (completing-read "Enter a day name: "
+                    (append calendar-day-name-array nil)
+                    nil t)))
+  
+(defun todos-read-time ()
+  "Prompt for and return a valid clock time as a string.
 
-(defun todos-toggle-mark-item (&optional n all)
-  "Mark item at point if unmarked, or unmark it if marked.
+Valid time strings are those matching `diary-time-regexp'.
+Typing `<return>' at the prompt returns the current time, if the
+user option `todos-always-add-time-string' is non-nil, otherwise
+the empty string (i.e., no time string)."
+  (let (valid answer)
+    (while (not valid)
+      (setq answer (read-string "Enter a clock time: " nil nil
+                               (when todos-always-add-time-string
+                                 (substring (current-time-string) 11 16))))
+      (when (or (string= "" answer)
+               (string-match diary-time-regexp answer))
+       (setq valid t)))
+    answer))
 
-With a positive numerical prefix argument N, change the
-markedness of the next N items.  With non-nil argument ALL, mark
-all visible items in the category (depending on visibility, all
-todo and done items, or just todo or just done items).
+(defun todos-convert-legacy-date-time ()
+  "Return converted date-time string.
+Helper function for `todos-convert-legacy-files'."
+  (let* ((year (match-string 1))
+        (month (match-string 2))
+        (monthname (calendar-month-name (string-to-number month) t))
+        (day (match-string 3))
+        (time (match-string 4))
+        dayname)
+    (replace-match "")
+    (insert (mapconcat 'eval calendar-date-display-form "")
+           (when time (concat " " time)))))
 
-The mark is the character \"*\" inserted in front of the item's
-priority number or the `todos-prefix' string; if `todos-prefix'
-is \"*\", then the mark is \"@\"."
-  (interactive "p")
-  (if all (goto-char (point-min)))
-  (unless (> n 0) (setq n 1))
-  (let ((i 0))
-    (while (or (and all (not (eobp)))
-              (< i n))
-      (let* ((cat (todos-current-category))
-            (ov (todos-item-marked-p))
-            (marked (assoc cat todos-categories-with-marks)))
-       (if (and ov (not all))
-           (progn
-             (delete-overlay ov)
-             (if (= (cdr marked) 1)    ; Deleted last mark in this category.
-                 (setq todos-categories-with-marks
-                       (assq-delete-all cat todos-categories-with-marks))
-               (setcdr marked (1- (cdr marked)))))
-         (when (todos-item-start)
-           (unless (and all (todos-item-marked-p))
-             (setq ov (make-overlay (point) (point)))
-             (overlay-put ov 'before-string todos-item-mark)
-             (if marked
-                 (setcdr marked (1+ (cdr marked)))
-               (push (cons cat 1) todos-categories-with-marks))))))
-      (todos-forward-item)
-      (setq i (1+ i)))))
+;; ---------------------------------------------------------------------------
+;;; Item filtering
 
-(defun todos-mark-category ()
-  "Put the \"*\" mark on all items in this category.
-\(If `todos-prefix' is \"*\", then the mark is \"@\".)"
-  (interactive)
-  (todos-toggle-mark-item 0 t))
+(defvar todos-multiple-files nil
+  "List of files returned by `todos-multiple-files' widget.")
 
-(defun todos-unmark-category ()
-  "Remove the \"*\" mark from all items in this category.
-\(If `todos-prefix' is \"*\", then the mark is \"@\".)"
-  (interactive)
-  (remove-overlays (point-min) (point-max) 'before-string todos-item-mark)
-  (setq todos-categories-with-marks
-       (delq (assoc (todos-current-category) todos-categories-with-marks)
-             todos-categories-with-marks)))
+(defvar todos-multiple-files-widget nil
+  "Variable holding widget created by `todos-multiple-files'.")
 
-(defun todos-update-merged-files ()
-  "Interactively add files to or remove from `todos-merged-files'.
-You can also customize `todos-merged-files' directly."
-  (interactive)                                ;FIXME
-  (let ((files (funcall todos-files-function)))
-    (dolist (f files)
-      (if (member f todos-merged-files)
-         (and (y-or-n-p
-               (format "Remove \"%s\" from list of merged Todos files? "
-                       (file-name-sans-extension (file-name-nondirectory f))))
-              (setq todos-merged-files (delete f todos-merged-files)))
-       (and (y-or-n-p
-             (format "Add \"%s\" to list of merged Todos files? "
-                     (file-name-sans-extension (file-name-nondirectory f))))
-            (setq todos-merged-files
-                  (append todos-merged-files (list f)))))))
-  (customize-save-variable 'todos-merged-files todos-merged-files))
-
-(defvar todos-top-priorities-widgets nil
-  "Widget placeholder used by `todos-set-top-priorities'.
-This variable temporarily holds user changed values which are
-saved to `todos-priorities-rules'.")
-
-(defun todos-set-top-priorities ()
-  ""
-  (interactive)
-  (let ((buf (get-buffer-create "*Todos Top Priorities*"))
-       (files (funcall todos-files-function))
-       file frules cats fwidget cwidgets rules)
-    (with-current-buffer buf
-      (let ((inhibit-read-only t))
-       (erase-buffer))
-      (remove-overlays)
+(defun todos-multiple-files ()
+  "Pop to a buffer with a widget for choosing multiple filter files."
+  (require 'widget)
+  (eval-when-compile
+    (require 'wid-edit))
+    (with-current-buffer (get-buffer-create "*Todos Filter Files*")
+      (pop-to-buffer (current-buffer))
+      (erase-buffer)
       (kill-all-local-variables)
-      (setq todos-top-priorities-widgets nil)
-      (dolist (f files)
-       (with-temp-buffer
-         (insert-file-contents f)
-         (setq file (file-name-sans-extension (file-name-nondirectory f))
-               frules (assoc file todos-priorities-rules)
-               cats (mapcar 'car (todos-set-categories))))
-       (setq fwidget
-             (widget-create 'editable-field
-                            :size 2
-                            :value (or (and frules (cadr frules))
-                                       "")
-                            :tag file
-                            :format " %v : %t\n"))
-       (dolist (c cats)
-         (let ((tp-num (cdr (assoc c cats)))
-               cwidget)
-           (widget-insert "  ")
-           (setq cwidget (widget-create 'editable-field
-                                        :size 2
-                                        :value (or tp-num "")
-                                        :tag c
-                                        :format " %v : %t\n"))
-           (push cwidget cwidgets)))
-       (push (cons fwidget cwidgets) todos-top-priorities-widgets))
-      (widget-insert "\n\n")
+      (widget-insert "Select files for generating the top priorities list.\n\n")
+      (setq todos-multiple-files-widget
+           (widget-create
+            `(set ,@(mapcar (lambda (x) (list 'const x))
+                            (mapcar 'todos-short-file-name
+                                    (funcall todos-files-function))))))
+      (widget-insert "\n")
       (widget-create 'push-button
                     :notify (lambda (widget &rest ignore)
-                              (kill-buffer))
+                              (setq todos-multiple-files 'quit)
+                              (quit-window t)
+                              (exit-recursive-edit))
                     "Cancel")
-      (widget-insert " ")
+      (widget-insert "   ")
       (widget-create 'push-button
                     :notify (lambda (&rest ignore)
-                              (let ((widgets todos-top-priorities-widgets)
-                                    (rules todos-priorities-rules)
-                                    tp-cats)
-                                (setq rules nil)
-                                (dolist (w widgets)
-                                  (let* ((fwid (car w))
-                                         (cwids (cdr w))
-                                         (fname (widget-get fwid :tag))
-                                         (fval (widget-value fwid)))
-                                    (dolist (c cwids)
-                                      (let ((cat (widget-get c :tag))
-                                            (cval (widget-value c)))
-                                        (push (cons cat cval) tp-cats)))
-                                    (push (list fname fval tp-cats) rules)))
-                                (setq todos-priorities-rules rules)
-                                (customize-save-variable 'todos-priorities-rules
-                                                         todos-priorities-rules)))
+                              (setq todos-multiple-files
+                                    (mapcar (lambda (f)
+                                              (concat todos-files-directory
+                                                      f ".todo"))
+                                            (widget-value
+                                             todos-multiple-files-widget)))
+                              (quit-window t)
+                              (exit-recursive-edit))
                     "Apply")
       (use-local-map widget-keymap)
       (widget-setup))
-    (set-window-buffer (selected-window) (set-buffer buf))))
-
-(defun todos-filter-items (&optional filter merge)
-  "Display a filtered list of items from different categories.
-
-The special items are either the first NUM items (the top priority items) or the items marked as diary entries in each category of the current Todos file.
-
-Number of entries for each category is given by NUM, which
-defaults to `todos-show-priorities'.  With non-nil argument
-MERGE list top priorities of all Todos files in
-`todos-merged-files'.  If `todos-prompt-merged-files' is non-nil,
-prompt to update the list of merged files."
+  (message "Click \"Apply\" after selecting files.")
+  (recursive-edit))
+
+;; FIXME: should done and archived items be included?  Maybe just for regexp
+;; and custom filters?
+(defun todos-filter-items (filter &optional multifile)
+  "Build and display a list of items from different categories.
+
+The items are selected according to the value of FILTER, which
+can be `top' for top priority items, `diary' for diary items,
+`regexp' for items matching a regular expresion entered by the
+user, or `custom' for items chosen by user-defined function
+`todos-filter-function'.
+
+With non-nil argument MULTIFILE list top priorities of multiple
+Todos files, by default those in `todos-filter-files'."
   (let ((num (if (consp filter) (cdr filter) todos-show-priorities))
-       (buf (get-buffer-create todos-tmp-buffer-name))
+       (buf (get-buffer-create todos-filter-buffer))
        (files (list todos-current-todos-file))
        regexp fname bufstr cat beg end done)
-    (when merge
-      ;; FIXME: same or different treatment for top priorities and other
-      ;; filters?  And what about todos-prompt-merged-files?
-      (setq files (if (member filter '(diary regexp custom))
-                     (or (and todos-prompt-merged-files
-                              (todos-update-merged-files))
-                         todos-merged-files
-                         (todos-update-merged-files))
-                   ;; Set merged files for top priorities.
-                   (or (mapcar (lambda (f)
-                             (let ((file (car f))
-                                   (val (nth 1 f)))
-                               (and val (not (zerop val))
-                                    (push file files))))
-                           todos-priorities-rules)
-                       (if (y-or-n-p "Choose files for merging top priorities? ")
-                           (progn (todos-set-top-priorities) (error ""))
-                         (error "No files are set for merging top priorities"))))))
-    (with-current-buffer buf
-      (erase-buffer)
-      (kill-all-local-variables)
-      (todos-filter-items-mode))
-    (when (eq filter 'regexp)
-      (setq regexp (read-string "Enter a regular expression: ")))
-    (save-current-buffer
-      (dolist (f files)
-       (setq fname (file-name-sans-extension (file-name-nondirectory f)))
-       (with-temp-buffer
-         (insert-file-contents f)
-         (goto-char (point-min))
-         ;; Unless the number of items to show was supplied by prefix
-         ;; argument of caller, override `todos-show-priorities' with the
-         ;; nonzero file-wide value from `todos-priorities-rules'.
-         (unless (consp filter)
-           (let ((tp-val (nth 1 (assoc fname todos-priorities-rules))))
-             (unless (zerop (length tp-val))
-               (setq num (string-to-number tp-val)))))
-         (unless (looking-at (concat "^" (regexp-quote todos-category-beg)))
-           (kill-line 1))
-         (while (re-search-forward
-                 (concat "^" (regexp-quote todos-category-beg) "\\(.+\\)\n")
-                 nil t)
-           (setq cat (match-string 1))
-           ;; Unless the number of items to show was supplied by prefix
-           ;; argument of caller, override `todos-show-priorities' with the
-           ;; nonzero category-wide value from `todos-priorities-rules'.
-           (unless (consp filter)
-             (let* ((cats (nth 2 (assoc fname todos-priorities-rules)))
-                    (tp-val (cdr (assoc cat cats))))
-               (unless (zerop (length tp-val))
-                 (setq num (string-to-number tp-val)))))
-           (delete-region (match-beginning 0) (match-end 0))
-           (setq beg (point)) ; Start of first entry.
-           (setq end (if (re-search-forward
-                          (concat "^" (regexp-quote todos-category-beg)) nil t)
-                         (match-beginning 0)
-                       (point-max)))
-           (goto-char beg)
-           (setq done
-                 (if (re-search-forward
-                      (concat "\n" (regexp-quote todos-category-done)) end t)
-                     (match-beginning 0)
-                   end))
-           (delete-region done end)
-           (setq end done)
-           (narrow-to-region beg end)  ; Process current category.
+    (when multifile
+      (setq files (if (or (consp filter) (null todos-filter-files))
+                     (progn (todos-multiple-files) todos-multiple-files)
+                   todos-filter-files)
+           todos-multiple-files nil))
+    (if (eq files 'quit) (keyboard-quit))
+    (if (null files)
+       (error "No files have been chosen for filtering")
+      (with-current-buffer buf
+       (erase-buffer)
+       (kill-all-local-variables)
+       (todos-filter-items-mode))
+      (when (eq filter 'regexp)
+       (setq regexp (read-string "Enter a regular expression: ")))
+      (save-current-buffer
+       (dolist (f files)
+         ;; Before inserting file contents into temp buffer, save a modified
+         ;; buffer visiting it.
+         (let ((bf (find-buffer-visiting f)))
+           (when (buffer-modified-p bf)
+             (with-current-buffer bf (save-buffer))))
+         (setq fname (todos-short-file-name f))
+         (with-temp-buffer
+           (insert-file-contents f)
            (goto-char (point-min))
-           ;; Apply the filter.
-           (cond ((eq filter 'diary)
-                  (while (not (eobp))
-                    (if (looking-at (regexp-quote todos-nondiary-start))
-                        (todos-remove-item)
-                      (todos-forward-item))))
-                 ((eq filter 'regexp)
-                  (while (not (eobp))
-                    (if (string-match regexp (todos-item-string))
-                        (todos-forward-item)
-                      (todos-remove-item))))
-                 ((eq filter 'custom)
-                  (if todos-filter-function
-                      (funcall todos-filter-function)
-                    (error "No custom filter function has been defined")))
-                 (t ; Filter top priority items.
-                  (todos-forward-item num)))
-             (setq beg (point))
-             (unless (member filter '(diary regexp custom))
-               (delete-region beg end))
-             (goto-char (point-min))
-             ;; Add file (if using merged files) and category tags to item.
-             (while (not (eobp))
-               (when (re-search-forward
-                      (concat todos-date-string-start todos-date-pattern
-                              "\\( " diary-time-regexp "\\)?"
-                              (regexp-quote todos-nondiary-end) "?")
-                      nil t)
-                 (insert (concat " [" (if merge (concat fname ":")) cat "]")))
-               (forward-line))
-             (widen))
-         (setq bufstr (buffer-string))
-         (with-current-buffer buf
-           (let (buffer-read-only)
-             (insert bufstr))))))
-    (set-window-buffer (selected-window) (set-buffer buf))
-    (todos-prefix-overlays)
-    (goto-char (point-min))
-    ;; FIXME: this is necessary -- why?
-    (font-lock-fontify-buffer)))
-
-(defun todos-top-priorities (&optional num)
-  "List top priorities of each category in `todos-merged-files'.
-Number of entries for each category is given by NUM, which
-defaults to `todos-show-priorities'."
-  (interactive "p")
-  (let ((arg (if num (cons 'top num) 'top)))
-    (todos-filter-items arg)))
+           (let (fnum)
+             ;; Unless the number of items to show was supplied by prefix
+             ;; argument of caller, override `todos-show-priorities' with the
+             ;; file-wide value from `todos-priorities-rules'.
+             (unless (consp filter)
+               (setq fnum (nth 1 (assoc f todos-priorities-rules))))
+             (unless (looking-at (concat "^" (regexp-quote todos-category-beg)))
+               (kill-line 1))
+             (while (re-search-forward
+                     (concat "^" (regexp-quote todos-category-beg) "\\(.+\\)\n")
+                     nil t)
+               (setq cat (match-string 1))
+               (let (cnum)
+                 ;; Unless the number of items to show was supplied by prefix
+                 ;; argument of caller, override the file-wide value from
+                 ;; `todos-priorities-rules' if set, else
+                 ;; `todos-show-priorities' with non-nil category-wide value
+                 ;; from `todos-priorities-rules'.
+                 (unless (consp filter)
+                   (let ((cats (nth 2 (assoc f todos-priorities-rules))))
+                     (setq cnum (or (cdr (assoc cat cats))
+                                    fnum
+                                    ;; FIXME: need this?
+                                    todos-show-priorities))))
+                 (delete-region (match-beginning 0) (match-end 0))
+                 (setq beg (point)) ; Start of first item.
+                 (setq end (if (re-search-forward
+                                (concat "^" (regexp-quote todos-category-beg))
+                                nil t)
+                               (match-beginning 0)
+                             (point-max)))
+                 (goto-char beg)
+                 (setq done
+                       (if (re-search-forward
+                            (concat "\n" (regexp-quote todos-category-done))
+                            end t)
+                           (match-beginning 0)
+                         end))
+                 ;; Leave done items only with regexp filter.
+                 ;; FIXME: and custom filter?
+                 (unless (eq filter 'regexp)
+                   (delete-region done end)
+                   (setq end done))
+                 (narrow-to-region beg end)    ; Process current category.
+                 (goto-char (point-min))
+                 ;; Apply the filter.
+                 (cond ((eq filter 'diary)
+                        (while (not (eobp))
+                          (if (looking-at (regexp-quote todos-nondiary-start))
+                              (todos-remove-item)
+                            (todos-forward-item))))
+                       ((eq filter 'regexp)
+                        (while (not (eobp))
+                          (if (looking-at todos-item-start)
+                              (if (string-match regexp (todos-item-string))
+                                  (todos-forward-item)
+                                (todos-remove-item))
+                            ;; Kill lines that aren't part of a todo or done
+                            ;; item (empty or todos-category-done).
+                            (delete-region (line-beginning-position)
+                                           (1+ (line-end-position))))
+                          ;; If last todo item in file matches regexp and
+                          ;; there are no following done items,
+                          ;; todos-category-done string is left dangling,
+                          ;; because todos-forward-item jumps over it.
+                          (if (and (eobp) (looking-back
+                                           (concat (regexp-quote todos-done-string)
+                                                   "\n")))
+                              (delete-region (point) (progn
+                                                       (forward-line -2)
+                                                       (point))))))
+                       ((eq filter 'custom)
+                        (if todos-filter-function
+                            (funcall todos-filter-function)
+                          (error "No custom filter function has been defined")))
+                       (t ; Filter top priority items.
+                        (setq num (or cnum fnum num))
+                        (unless (zerop num)
+                          (todos-forward-item num))))
+                 (setq beg (point))
+                 (unless (member filter '(diary regexp custom))
+                   (delete-region beg end))
+                 (goto-char (point-min))
+                 ;; Add file (if using multiple files) and category tags to
+                 ;; item.
+                 (while (not (eobp))
+                   (when (re-search-forward
+                          (concat "\\(" todos-done-string-start
+                                  todos-date-pattern "\\( " diary-time-regexp
+                                  "\\)?]\\)\\|\\("
+                                  ;; todos-date-string-start doesn't work
+                                  ;; here because of `^'
+                                  "\\(" (regexp-quote todos-nondiary-start)
+                                  "\\|" (regexp-quote diary-nonmarking-symbol)
+                                  "\\)?" todos-date-pattern "\\( "
+                                  diary-time-regexp "\\)?"
+                                  (regexp-quote todos-nondiary-end) "?\\)")
+                          nil t)
+                     (insert (concat " [" (if multifile (concat fname ":"))
+                                     cat "]")))
+                   (forward-line))
+                 (widen)))
+               (setq bufstr (buffer-string))
+               (with-current-buffer buf
+                 (let (buffer-read-only)
+                   (insert bufstr)))))))
+      ;; FIXME: let-bind todos-mode-line-control according to FILTER?
+      (set-window-buffer (selected-window) (set-buffer buf))
+      (todos-prefix-overlays)
+      (goto-char (point-min))
+      ;; FIXME: this is necessary -- why?
+      (font-lock-fontify-buffer))))
+
+(defun todos-set-top-priorities (&optional arg)
+  "Set number of top priorities shown by `todos-top-priorities'.
+With non-nil ARG, set the number only for the current Todos
+category; otherwise, set the number for all categories in the
+current Todos file.
+
+Calling this function via either of the commands
+`todos-set-top-priorities-in-file' or
+`todos-set-top-priorities-in-category' is the recommended way to
+set the user customizable option `todos-priorities-rules'."
+  (let* ((cat (todos-current-category))
+        (file todos-current-todos-file)
+        (rules todos-priorities-rules)
+        (frule (assoc-string file rules))
+        (crule (assoc-string cat (nth 2 frule)))
+        (cur (or (if arg (cdr crule) (nth 1 frule))
+                 todos-show-priorities))
+        (prompt (concat "Current number of top priorities in this "
+                        (if arg "category" "file") ": %d; "
+                        "enter new number: "))
+        (new "-1")
+        nrule)
+    (while (or (not (string-match "[0-9]+" new)) ; Don't accept "" or "bla".
+              (< (string-to-number new) 0))
+      (let ((cur0 cur))
+       (setq new (read-string (format prompt cur0) nil nil cur0)
+             prompt "Enter a non-negative number: "
+             cur0 nil)))
+    (setq new (string-to-number new))
+    (setq nrule (if arg
+                   (append (nth 2 (delete crule frule)) (list (cons cat new)))
+                 (append (list file new) (list (nth 2 frule)))))
+    (setq rules (cons (if arg
+                         (list file cur nrule)
+                       nrule)
+                     (delete frule rules)))
+    (customize-save-variable 'todos-priorities-rules rules)))
 
-(defun todos-merged-top-priorities (&optional num)
-  "List top priorities of each category in `todos-merged-files'.
-Number of entries for each category is given by NUM, which
-defaults to `todos-show-priorities'."
-  (interactive "p")
-  (let ((arg (if num (cons 'top num) 'top)))
-    (todos-filter-items arg t)))
 
-(defun todos-diary-items ()
-  "Display todo items for diary inclusion in this Todos file."
-  (interactive)
-  (todos-filter-items 'diary))
+;; ---------------------------------------------------------------------------
+;;; Sorting and display routines for Todos Categories mode.
 
-(defun todos-merged-diary-items ()
-  "Display todo items for diary inclusion in one or more Todos file.
-The files are those listed in `todos-merged-files'."
-  (interactive)
-  (todos-filter-items 'diary t))
+(defun todos-longest-category-name-length (categories)
+  "Return the length of the longest name in list CATEGORIES."
+  (let ((longest 0))
+    (dolist (c categories longest)
+      (setq longest (max longest (length c))))))
 
-(defun todos-regexp-items ()
-  "Display todo items matching a user-entered regular expression.
-The items are those in the current Todos file."
-  (interactive)
-  (todos-filter-items 'regexp))
+(defun todos-padded-string (str)
+  "Return string STR padded with spaces.
+The placement of the padding is determined by the value of user
+option `todos-categories-align'."
+  (let* ((categories (mapcar 'car todos-categories))
+        (len (max (todos-longest-category-name-length categories)
+                  (length todos-categories-category-label)))
+        (strlen (length str))
+        (strlen-odd (eq (logand strlen 1) 1)) ; oddp from cl.el
+        (padding (max 0 (/ (- len strlen) 2)))
+        (padding-left (cond ((eq todos-categories-align 'left) 0)
+                            ((eq todos-categories-align 'center) padding)
+                            ((eq todos-categories-align 'right)
+                             (if strlen-odd (1+ (* padding 2)) (* padding 2)))))
+        (padding-right (cond ((eq todos-categories-align 'left)
+                              (if strlen-odd (1+ (* padding 2)) (* padding 2)))
+                             ((eq todos-categories-align 'center)
+                              (if strlen-odd (1+ padding) padding))
+                             ((eq todos-categories-align 'right) 0))))
+    (concat (make-string padding-left 32) str (make-string padding-right 32))))
 
-(defun todos-merged-regexp-items ()
-  "Display todo items matching a user-entered regular expression.
-The items are those in the files listed in `todos-merged-files'."
-  (interactive)
-  (todos-filter-items 'regexp t))
+(defvar todos-descending-counts nil
+  "List of keys for category counts sorted in descending order.")
 
-(defun todos-custom-items ()
-  "Display todo items filtered by `todos-filter-function'.
-The items are those in the current Todos file."
-  (interactive)
-  (todos-filter-items 'custom))
+(defun todos-sort (list &optional key)
+  "Return a copy of LIST, possibly sorted according to KEY."
+  (let* ((l (copy-sequence list))
+        (fn (if (eq key 'alpha)
+                  (lambda (x) (upcase x)) ; Alphabetize case insensitively.
+                (lambda (x) (todos-get-count key x))))
+        (descending (member key todos-descending-counts))
+        (cmp (if (eq key 'alpha)
+                 'string<
+               (if descending '< '>)))
+        (pred (lambda (s1 s2) (let ((t1 (funcall fn (car s1)))
+                                    (t2 (funcall fn (car s2))))
+                                (funcall cmp t1 t2)))))
+    (when key
+      (setq l (sort l pred))
+      (if descending
+         (setq todos-descending-counts
+               (delete key todos-descending-counts))
+       (push key todos-descending-counts)))
+    l))
 
-(defun todos-merged-custom-items ()
-  "Display todo items filtered by `todos-filter-function'.
-The items are those in the files listed in `todos-merged-files'."
-  (interactive)
-  (todos-filter-items 'custom t))
+(defun todos-display-sorted (type)
+  "Keep point on the TYPE count sorting button just clicked."
+  (let ((opoint (point)))
+    (todos-update-categories-display type)
+    (goto-char opoint)))
 
-;;; Navigation
+(defun todos-label-to-key (label)
+  "Return symbol for sort key associated with LABEL."
+  (let (key)
+    (cond ((string= label todos-categories-category-label)
+          (setq key 'alpha))
+         ((string= label todos-categories-todo-label)
+          (setq key 'todo))
+         ((string= label todos-categories-diary-label)
+          (setq key 'diary))
+         ((string= label todos-categories-done-label)
+          (setq key 'done))
+         ((string= label todos-categories-archived-label)
+          (setq key 'archived)))
+    key))
 
-(defun todos-forward-category (&optional back)
-  "Visit the numerically next category in this Todos file.
-With non-nil argument BACK, visit the numerically previous
-category."
-  (interactive)
-  (setq todos-category-number
-        (1+ (mod (- todos-category-number (if back 2 0))
-                (length todos-categories))))
-  (todos-category-select)
-  (goto-char (point-min)))
+(defun todos-insert-sort-button (label)
+  "Insert button for displaying categories sorted by item counts.
+LABEL determines which type of count is sorted."
+  (setq str (if (string= label todos-categories-category-label)
+               (todos-padded-string label)
+             label))
+  (setq beg (point))
+  (setq end (+ beg (length str)))
+  (insert-button str 'face nil
+                'action
+                `(lambda (button)
+                   (let ((key (todos-label-to-key ,label)))
+                     (if (and (member key todos-descending-counts)
+                              (eq key 'alpha))
+                         (progn
+                           ;; If display is alphabetical, switch back to
+                           ;; category order.
+                           (todos-display-sorted nil)
+                           (setq todos-descending-counts
+                                 (delete key todos-descending-counts)))
+                       (todos-display-sorted key)))))
+  (setq ovl (make-overlay beg end))
+  (overlay-put ovl 'face 'todos-button))
 
-(defun todos-backward-category ()
-  "Visit the numerically previous category in this Todos file."
-  (interactive)
-  (todos-forward-category t))
+(defun todos-total-item-counts ()
+  "Return a list of total item counts for the current file."
+  (mapcar (lambda (i) (apply '+ (mapcar (lambda (l) (aref l i))
+                                       (mapcar 'cdr todos-categories))))
+         (list 0 1 2 3)))
 
-;; FIXME: autoload?
-(defun todos-jump-to-category (&optional cat other-file)
-  "Jump to a category in this or another Todos file.
-Optional argument CAT provides the category name.  Otherwise,
-prompt for the category, with TAB completion on existing
-categories.  If a non-existing category name is entered, ask
-whether to add a new category with this name, if affirmed, do so,
-then jump to that category.  With non-nil argument OTHER-FILE,
-prompt for a Todos file, otherwise jump within the current Todos
-file."
-  (interactive)
-  (let ((file (or (and other-file
-                      (todos-read-file-name "Choose a Todos file: " nil t))
-                 ;; Jump to archived-only Categories from Todos Categories mode.
-                 (and cat
-                      todos-ignore-archived-categories
-                      (zerop (todos-get-count 'todo cat))
-                      (zerop (todos-get-count 'done cat))
-                      (not (zerop (todos-get-count 'archived cat)))
-                      (concat (file-name-sans-extension
-                               todos-current-todos-file) ".toda"))
-                 todos-current-todos-file
-                 ;; If invoked from outside of Todos mode before todos-show...
-                 todos-default-todos-file)))
-       (with-current-buffer (find-file-noselect file)
-         (and other-file (setq todos-current-todos-file file))
-         (let ((category (or (and (assoc cat todos-categories) cat)
-                             (todos-read-category "Jump to category: "))))
-           ;; ;; FIXME: why is this needed?
-           ;; (if (string= "" category)
-           ;;  (setq category (todos-current-category)))
-           ;; Clean up after selecting category in Todos Categories mode.
-           (if (string= (buffer-name) todos-categories-buffer)
-               (kill-buffer))
-           (if (or cat other-file)
-               (set-window-buffer (selected-window)
-                                  (set-buffer (get-file-buffer file))))
-           (unless todos-global-current-todos-file
-             (setq todos-global-current-todos-file todos-current-todos-file))
-           (todos-category-number category)
-           (if (> todos-category-number (length todos-categories))
-               (setq todos-category-number (todos-add-category category)))
-           (todos-category-select)
-           (goto-char (point-min))))))
+(defun todos-insert-category-line (cat &optional nonum)
+  "Insert button displaying category CAT's name and item counts.
+With non-nil argument NONUM show only these; otherwise, insert a
+number in front of the button indicating the category's priority.
+The number and the category name are separated by the string
+which is the value of the user option
+`todos-categories-number-separator'."
+  (let* ((archive (member todos-current-todos-file todos-archives))
+       (str (todos-padded-string cat))
+       (opoint (point)))
+    ;; num is declared in caller.
+    (setq num (1+ num))
+    (insert-button
+     (concat (if nonum
+                (make-string (+ 4 (length todos-categories-number-separator))
+                             32)
+              (format " %3d%s" num todos-categories-number-separator))
+            str
+            (mapconcat (lambda (elt)
+                         (concat
+                          (make-string (1+ (/ (length (car elt)) 2)) 32) ; label
+                          (format "%3d" (todos-get-count (cdr elt) cat)) ; count
+                          ;; Add an extra space if label length is odd
+                          ;; (using def of oddp from cl.el).
+                          (if (eq (logand (length (car elt)) 1) 1) " ")))
+                       (if archive
+                           (list (cons todos-categories-done-label 'done))
+                         (list (cons todos-categories-todo-label 'todo)
+                               (cons todos-categories-diary-label 'diary)
+                               (cons todos-categories-done-label 'done)
+                               (cons todos-categories-archived-label
+                                     'archived)))
+                         ""))
+     'face (if (and todos-ignore-archived-categories
+                   (zerop (todos-get-count 'todo cat))
+                   (zerop (todos-get-count 'done cat))
+                   (not (zerop (todos-get-count 'archived cat))))
+              'todos-archived-only
+            nil)
+     'action `(lambda (button) (let ((buf (current-buffer)))
+                                (todos-jump-to-category ,cat)
+                                (kill-buffer buf))))
+    ;; Highlight the sorted count column.
+    (let* ((beg (+ opoint 6 (length str)))
+          end ovl)
+      (cond ((eq nonum 'todo)
+            (setq beg (+ beg 1 (/ (length todos-categories-todo-label) 2))))
+           ((eq nonum 'diary)
+            (setq beg (+ beg 1 (length todos-categories-todo-label)
+                          2 (/ (length todos-categories-diary-label) 2))))
+           ((eq nonum 'done)
+            (setq beg (+ beg 1 (length todos-categories-todo-label)
+                          2 (length todos-categories-diary-label)
+                          2 (/ (length todos-categories-done-label) 2))))
+           ((eq nonum 'archived)
+            (setq beg (+ beg 1 (length todos-categories-todo-label)
+                          2 (length todos-categories-diary-label)
+                          2 (length todos-categories-done-label)
+                          2 (/ (length todos-categories-archived-label) 2)))))
+      (unless (= beg (+ opoint 6 (length str)))
+       (setq end (+ beg 4))
+       (setq ovl (make-overlay beg end))
+       (overlay-put ovl 'face 'todos-sorted-column)))
+    (newline)))
 
-(defun todos-jump-to-category-other-file ()
-  "Jump to a category in another Todos file.
-The category is chosen by prompt, with TAB completion."
-  (interactive)
-  (todos-jump-to-category nil t))
+(defun todos-display-categories-1 ()
+  "Prepare buffer for displaying table of categories and item counts."
+  (unless (eq major-mode 'todos-categories-mode)
+    (setq todos-global-current-todos-file (or todos-current-todos-file
+                                             todos-default-todos-file))
+    (set-window-buffer (selected-window)
+                      (set-buffer (get-buffer-create todos-categories-buffer)))
+    (kill-all-local-variables)
+    (todos-categories-mode)
+    (let (buffer-read-only) 
+      (erase-buffer)
+      ;; FIXME: add usage tips?
+      (insert (format "Category counts for Todos file \"%s\"."
+                     (todos-short-file-name todos-current-todos-file)))
+      (newline 2)
+      ;; Make space for the column of category numbers.
+      (insert (make-string (+ 4 (length todos-categories-number-separator)) 32))
+      ;; Add the category and item count buttons (if this is the list of
+      ;; categories in an archive, show only done item counts).
+      (todos-insert-sort-button todos-categories-category-label)
+      (if (member todos-current-todos-file todos-archives)
+         (insert (concat (make-string 6 32)
+                         (format "%s" todos-categories-archived-label)))
+       (insert (make-string 3 32))
+       (todos-insert-sort-button todos-categories-todo-label)
+       (insert (make-string 2 32))
+       (todos-insert-sort-button todos-categories-diary-label)
+       (insert (make-string 2 32))
+       (todos-insert-sort-button todos-categories-done-label)
+       (insert (make-string 2 32))
+       (todos-insert-sort-button todos-categories-archived-label))
+      (newline 2))))
+
+(defun todos-update-categories-display (sortkey)
+  ""
+  (let* ((cats0 (if (and todos-ignore-archived-categories
+                          (not (eq major-mode 'todos-categories-mode)))
+                     todos-categories-full
+                   todos-categories))
+          (cats (todos-sort cats0 sortkey))
+          (archive (member todos-current-todos-file todos-archives))
+          ;; `num' is used by todos-insert-category-line.
+          (num 0)
+          ;; Find start of Category button if we just entered Todos Categories
+          ;; mode.
+          (pt (if (eq (point) (point-max))
+                  (save-excursion
+                    (forward-line -2)
+                    (goto-char (next-single-char-property-change
+                                (point) 'face nil (line-end-position))))))
+          (buffer-read-only))
+      (forward-line 2)
+      (delete-region (point) (point-max))
+      ;; Fill in the table with buttonized lines, each showing a category and
+      ;; its item counts.
+      (mapc (lambda (cat) (todos-insert-category-line cat sortkey))
+           (mapcar 'car cats))
+      (newline)
+      ;; Add a line showing item count totals.
+      (insert (make-string (+ 4 (length todos-categories-number-separator)) 32)
+             (todos-padded-string todos-categories-totals-label)
+             (mapconcat
+              (lambda (elt)
+                (concat
+                 (make-string (1+ (/ (length (car elt)) 2)) 32)
+                 (format "%3d" (nth (cdr elt) (todos-total-item-counts)))
+                 ;; Add an extra space if label length is odd (using
+                 ;; definition of oddp from cl.el).
+                 (if (eq (logand (length (car elt)) 1) 1) " ")))
+              (if archive
+                  (list (cons todos-categories-done-label 2))
+                (list (cons todos-categories-todo-label 0)
+                      (cons todos-categories-diary-label 1)
+                      (cons todos-categories-done-label 2)
+                      (cons todos-categories-archived-label 3)))
+              ""))
+      ;; Put cursor on Category button initially.
+      (if pt (goto-char pt))
+      (setq buffer-read-only t)))
 
-;; FIXME ? disallow prefix arg value < 1 (re-search-* allows these)
-(defun todos-forward-item (&optional count)
-  "Move point down to start of item with next lower priority.
-With numerical prefix COUNT, move point COUNT items downward,"
-  (interactive "P")
-  (let* ((not-done (not (or (todos-done-item-p) (looking-at "^$"))))
-        (start (line-end-position)))
-    (goto-char start)
-    (if (re-search-forward todos-item-start nil t (or count 1))
-       (goto-char (match-beginning 0))
-      (goto-char (point-max)))
-    ;; If points advances by one from a todo to a done item, go back to the
-    ;; space above todos-done-separator, since that is a legitimate place to
-    ;; insert an item.  But skip this space if count > 1, since that should
-    ;; only stop on an item (FIXME: or not?)
-    (when (and not-done (todos-done-item-p))
-      (if (or (not count) (= count 1))
-         (re-search-backward "^$" start t)))))
+;; ---------------------------------------------------------------------------
+;;; Todos insertion commands, key bindings and keymap
 
-(defun todos-backward-item (&optional count)
-  "Move point up to start of item with next higher priority.
-With numerical prefix COUNT, move point COUNT items upward,"
-  (interactive "P")
-  (let* ((done (todos-done-item-p)))
-    ;; FIXME ? this moves to bob if on the first item (but so does previous-line)
-    (todos-item-start)
-    (unless (bobp)
-      (re-search-backward todos-item-start nil t (or count 1)))
-    ;; If points advances by one from a done to a todo item, go back to the
-    ;; space above todos-done-separator, since that is a legitimate place to
-    ;; insert an item.  But skip this space if count > 1, since that should
-    ;; only stop on an item (FIXME: or not?)
-    (when (and done (not (todos-done-item-p))
-              (or (not count) (= count 1)))
-      (re-search-forward (concat "^" (regexp-quote todos-category-done)) nil t)
-      (forward-line -1))))
+;; Can either of these be included in Emacs?  The originals are GFDL'd.
+;; Slightly reformulated from
+;; http://rosettacode.org/wiki/Power_set#Common_Lisp.
+(defun powerset-recursive (l)
+  (cond ((null l)
+        (list nil))
+       (t
+        (let ((prev (todos-powerset (cdr l))))
+          (append (mapcar (lambda (elt) (cons (car l) elt)) prev)
+                  prev)))))
+;; Elisp implementation of http://rosettacode.org/wiki/Power_set#C
+(defun powerset-bitwise (l)
+  (let ((binnum (lsh 1 (length l)))
+        pset elt)
+    (dotimes (i binnum)
+      (let ((bits i)
+           (ll l))
+       (while (not (zerop bits))
+         (let ((arg (pop ll)))
+           (unless (zerop (logand bits 1))
+             (setq elt (append elt (list arg))))
+           (setq bits (lsh bits -1))))
+       (setq pset (append pset (list elt)))
+       (setq elt nil)))
+    pset))
+
+;; (defalias 'todos-powerset 'powerset-recursive)
+(defalias 'todos-powerset 'powerset-bitwise)
 
-(defun todos-search ()
-  "Search for a regular expression in this Todos file.
-The search runs through the whole file and encompasses all and
-only todo and done items; it excludes category names.  Multiple
-matches are shown sequentially, highlighted in `todos-search'
-face."
-  (interactive)
-  (let ((regex (read-from-minibuffer "Enter a search string (regexp): "))
-       (opoint (point))
-       matches match cat in-done ov mlen msg)
-    (widen)
-    (goto-char (point-min))
-    (while (not (eobp))
-      (setq match (re-search-forward regex nil t))
-      (goto-char (line-beginning-position))
-      (unless (or (equal (point) 1)
-                 (looking-at (concat "^" (regexp-quote todos-category-beg))))
-       (if match (push match matches)))
-      (forward-line))
-    (setq matches (reverse matches))
-    (if matches
-       (catch 'stop
-         (while matches
-           (setq match (pop matches))
-           (goto-char match)
-           (todos-item-start)
-           (when (looking-at todos-done-string-start)
-             (setq in-done t))
-           (re-search-backward (concat "^" (regexp-quote todos-category-beg)
-                                       "\\(.*\\)\n") nil t)
-           (setq cat (match-string-no-properties 1))
-           (todos-category-number cat)
-           (todos-category-select)
-           (if in-done
-               (unless todos-show-with-done (todos-toggle-view-done-items)))
-           (goto-char match)
-           (setq ov (make-overlay (- (point) (length regex)) (point)))
-           (overlay-put ov 'face 'todos-search)
-           (when matches
-             (setq mlen (length matches))
-             (if (y-or-n-p
-                  (if (> mlen 1)
-                      (format "There are %d more matches; go to next match? "
-                              mlen)
-                    "There is one more match; go to it? "))
-                 (widen)
-               (throw 'stop (setq msg (if (> mlen 1)
-                                          (format "There are %d more matches."
-                                                  mlen)
-                                        "There is one more match."))))))
-         (setq msg "There are no more matches."))
-      (todos-category-select)
-      (goto-char opoint)
-      (message "No match for \"%s\"" regex))
-    (when msg
-      (if (y-or-n-p (concat msg "\nUnhighlight matches? "))
-         (todos-clear-matches)
-       (message "You can unhighlight the matches later by typing %s"
-                (key-description (car (where-is-internal
-                                       'todos-clear-matches))))))))
+;; Return list of lists of non-nil atoms produced from ARGLIST.  The elements
+;; of ARGLIST may be atoms or lists.
+(defun todos-gen-arglists (arglist)
+  (let (arglists)
+    (while arglist
+      (let ((arg (pop arglist)))
+       (cond ((symbolp arg)
+              (setq arglists (if arglists
+                                 (mapcar (lambda (l) (push arg l)) arglists)
+                               (list (push arg arglists)))))
+             ((listp arg)
+              (setq arglists
+                    (mapcar (lambda (a)
+                              (if (= 1 (length arglists))
+                                  (apply (lambda (l) (push a l)) arglists)
+                                (mapcar (lambda (l) (push a l)) arglists)))
+                            arg))))))
+    (setq arglists (mapcar 'reverse (apply 'append (mapc 'car arglists))))))
 
-(defun todos-clear-matches ()
-  "Remove highlighting on matches found by todos-search."
-  (interactive)
-  (remove-overlays 1 (1+ (buffer-size)) 'face 'todos-search))
+(defvar todos-insertion-commands-args-genlist
+  '(diary nonmarking (calendar date dayname) time (here region))
+  "Generator list for argument lists of Todos insertion commands.")
 
-;;; Editing
+(defvar todos-insertion-commands-args
+  (let ((argslist (todos-gen-arglists todos-insertion-commands-args-genlist))
+       res new)
+    (setq res (remove-duplicates
+              (apply 'append (mapcar 'todos-powerset argslist)) :test 'equal))
+    (dolist (l res)
+      (unless (= 5 (length l))
+       (let ((v (make-vector 5 nil)) elt)
+         (while l
+           (setq elt (pop l))
+           (cond ((eq elt 'diary)
+                  (aset v 0 elt))
+                 ((eq elt 'nonmarking)
+                  (aset v 1 elt))
+                 ((or (eq elt 'calendar)
+                      (eq elt 'date)
+                      (eq elt 'dayname))
+                  (aset v 2 elt))
+                 ((eq elt 'time)
+                  (aset v 3 elt))
+                 ((or (eq elt 'here)
+                      (eq elt 'region))
+                  (aset v 4 elt))))
+         (setq l (append v nil))))
+      (setq new (append new (list l))))
+    new)
+  "List of all argument lists for Todos insertion commands.")
 
-(defun todos-add-file ()
-  "Name and add a new Todos file.
-Interactively, prompt for a category and display it.
-Noninteractively, return the name of the new file."
-  (interactive)
-  (let ((default-file (if todos-default-todos-file
-                         (file-name-sans-extension
-                          (file-name-nondirectory todos-default-todos-file))))
-       file prompt shortname)
-    (while
-       (and
-        (cond
-         ((or (not file) (member file todos-files))
-          (setq prompt (concat "Enter name of new Todos file "
-                               "(TAB or SPC to see existing Todos files): ")))
-         ((string-equal file "")
-          (setq prompt "Enter a non-empty name: "))
-         ((string-match "\\`\\s-+\\'" file)
-          (setq prompt "Enter a name that is not only white space: ")))
-        (setq file (todos-read-file-name prompt))))
-    (setq shortname (file-name-sans-extension (file-name-nondirectory file)))
-    (with-current-buffer (get-buffer-create file)
-      (erase-buffer)
-      (write-region (point-min) (point-max) file nil 'nomessage nil t)
-      (kill-buffer file))
-    ;; FIXME: todos-change-default-file yields a Custom mismatch
-    ;; (if (or (not default-file)
-    ;;             (yes-or-no-p (concat (format "Make \"%s\" new default Todos file "
-    ;;                                          shortname)
-    ;;                                  (format "[current default is \"%s\"]? "
-    ;;                                          default-file))))
-    ;;         (todos-change-default-file file)
-    ;;   (message "\"%s\" remains the default Todos file." default-file))
-    (if (called-interactively-p)
-       (progn
-         (setq todos-current-todos-file file)
-         (todos-show))
-      file)))
+(defun todos-insertion-command-name (arglist)
+  "Generate Todos insertion command name from ARGLIST."
+  (replace-regexp-in-string
+   "-\\_>" ""
+   (replace-regexp-in-string
+    "-+" "-"
+    (concat "todos-item-insert-"
+           (mapconcat (lambda (e) (if e (symbol-name e))) arglist "-")))))
 
-;; FIXME: omit this and just use defcustom?  Says "changed outside of Custom
-;; (mismatch)"
-(defun todos-change-default-file (&optional file)
-  ""
-  (interactive)
-  (let ((new-default (or file
-                        (todos-read-file-name "Choose new default Todos file: "
-                                              nil t))))
-    (customize-save-variable 'todos-default-todos-file new-default)
-    (message "\"%s\" is new default Todos file."
-            (file-name-sans-extension (file-name-nondirectory new-default)))))
+(defvar todos-insertion-commands-names
+  (mapcar (lambda (l)
+          (todos-insertion-command-name l))
+         todos-insertion-commands-args)
+  "List of names of Todos insertion commands.")
 
-(defun todos-add-category (&optional cat)
-  "Add a new category to the current Todos file.
-Called interactively, prompt for category name, then visit the
-category in Todos mode.  Non-interactively, argument CAT provides
-the category name, which is also the return value."
-  (interactive)
-  (let* ((buffer-read-only)
-        ;; FIXME: check against todos-archive-done-item-or-items with empty file
-        (buf (find-file-noselect todos-current-todos-file t))
-        ;; (buf (get-file-buffer todos-current-todos-file))
-        (num (1+ (length todos-categories)))
-        (counts (make-vector 4 0)))    ; [todo diary done archived]
-    (unless (zerop (buffer-size buf))
-      (and (null todos-categories)
-          (error "Error in %s: File is non-empty but contains no category"
-                 todos-current-todos-file)))
-    (unless cat (setq cat (read-from-minibuffer "Enter new category name: ")))
-    (with-current-buffer buf
-      (setq cat (todos-validate-category-name cat))
-      (setq todos-categories (append todos-categories (list (cons cat counts))))
-      (widen)
-      (goto-char (point-max))
-      (save-excursion                  ; Save point for todos-category-select.
-       (insert todos-category-beg cat "\n\n" todos-category-done "\n"))
-      (todos-update-categories-sexp)
-      ;; If called by command, display the newly added category, else return
-      ;; the category number to the caller.
-      (if (called-interactively-p 'any)          ; FIXME?
-         (progn
-           (setq todos-category-number num)
-           (todos-category-select))
-       num))))
+(defmacro todos-define-insertion-command (&rest args)
+  (let ((name (intern (todos-insertion-command-name args)))
+       (arg0 (nth 0 args))
+       (arg1 (nth 1 args))
+       (arg2 (nth 2 args))
+       (arg3 (nth 3 args))
+       (arg4 (nth 4 args)))
+    `(defun ,name (&optional arg)
+       "Todos item insertion command."
+       (interactive)
+       (todos-insert-item arg ',arg0 ',arg1 ',arg2 ',arg3 ',arg4))))
 
-(defun todos-rename-category ()
-  "Rename current Todos category.
-If this file has an archive containing this category, rename the
-category there as well."
-  (interactive)
-  (let* ((cat (todos-current-category))
-        (new (read-from-minibuffer (format "Rename category \"%s\" to: " cat))))
-    (setq new (todos-validate-category-name new))
-    (let* ((ofile todos-current-todos-file)
-          (archive (concat (file-name-sans-extension ofile) ".toda"))
-          (buffers (append (list ofile)
-                           (unless (zerop (todos-get-count 'archived cat))
-                             (list archive)))))
-      (dolist (buf buffers)
-       (with-current-buffer (find-file-noselect buf)
-         (let (buffer-read-only)
-           (setq todos-categories (todos-set-categories))
-           (save-excursion
-             (save-restriction
-               (setcar (assoc cat todos-categories) new)
-               (widen)
-               (goto-char (point-min))
-               (todos-update-categories-sexp)
-               (re-search-forward (concat (regexp-quote todos-category-beg)
-                                          "\\(" (regexp-quote cat) "\\)\n")
-                                  nil t)
-               (replace-match new t t nil 1)))))))
-    (setq mode-line-buffer-identification
-         (funcall todos-mode-line-function new)))
-  (save-excursion (todos-category-select)))
+(defvar todos-insertion-commands
+  (mapcar (lambda (c)
+           (eval `(todos-define-insertion-command ,@c)))
+         todos-insertion-commands-args)
+  "List of Todos insertion commands.")
 
-(defun todos-delete-category (&optional arg)
-  "Delete current Todos category provided it is empty.
-With ARG non-nil delete the category unconditionally,
-i.e. including all existing todo and done items."
-  (interactive "P")
-  (let* ((cat (todos-current-category))
-        (todo (todos-get-count 'todo cat))
-        (done (todos-get-count 'done cat))
-        (archived (todos-get-count 'archived cat)))
-    (if (and (not arg)
-            (or (> todo 0) (> done 0)))
-       (message "To delete a non-empty category, type C-u D.")
-      (when (yes-or-no-p (concat "Permanently remove category \"" cat
-                                "\"" (and arg " and all its entries") "? "))
-       ;; FIXME ? optionally delete archived category as well?
-       (when (and archived
-                  (y-or-n-p (concat "This category has archived items; "
-                                    "the archived category will remain\n"
-                                    "after deleting the todo category.  "
-                                    "Do you still want to delete it\n"
-                                    "(see 'todos-ignore-archived-categories' "
-                                    "for another option)? ")))
-         (widen)
-         (let ((buffer-read-only)
-               (beg (re-search-backward
-                     (concat "^" (regexp-quote (concat todos-category-beg cat))
-                             "\n") nil t))
-               (end (if (re-search-forward
-                         (concat "\n\\(" (regexp-quote todos-category-beg)
-                                 ".*\n\\)") nil t)
-                        (match-beginning 1)
-                      (point-max))))
-           (remove-overlays beg end)
-           (delete-region beg end)
-           (setq todos-categories (delete (assoc cat todos-categories)
-                                          todos-categories))
-           (todos-update-categories-sexp)
-           (setq todos-category-number
-                 (1+ (mod todos-category-number (length todos-categories))))
-           (todos-category-select)
-           (goto-char (point-min))
-           (message "Deleted category %s" cat)))))))
+(defvar todos-insertion-commands-arg-key-list
+  '(("diary" "y" "yy")
+    ("nonmarking" "k" "kk")
+    ("calendar" "c" "cc")
+    ("date" "d" "dd")
+    ("dayname" "n" "nn")
+    ("time" "t" "tt")
+    ("here" "h" "h")
+    ("region" "r" "r"))
+  "")    
 
-(defun todos-raise-category (&optional lower)
-  "Raise priority of category point is on in Categories buffer.
-With non-nil argument LOWER, lower the category's priority."
-  (interactive)
-  (let (num)
-    (save-excursion
-      (forward-line 0)
-      (skip-chars-forward " ")
-      (setq num (number-at-point)))
-    (when (and num (if lower
-                      (< num (length todos-categories))
-                    (> num 1)))
-      (let* ((col (current-column))
-            (beg (progn (forward-line (if lower 0 -1)) (point)))
-            (num1 (progn (skip-chars-forward " ") (1- (number-at-point))))
-            (num2 (1+ num1))
-            (end (progn (forward-line 2) (point)))
-            (catvec (vconcat todos-categories))
-            (cat1-list (aref catvec num1))
-            (cat2-list (aref catvec num2))
-            (cat1 (car cat1-list))
-            (cat2 (car cat2-list))
-            buffer-read-only newcats)
-       (delete-region beg end)
-       (setq num1 (1+ num1))
-       (setq num2 (1- num2))
-       (setq num num2)
-       (todos-insert-category-line cat2)
-       (setq num num1)
-       (todos-insert-category-line cat1)
-       (aset catvec num2 (cons cat2 (cdr cat2-list)))
-       (aset catvec num1 (cons cat1 (cdr cat1-list)))
-       (setq todos-categories (append catvec nil))
-       (setq newcats todos-categories)
-       (with-current-buffer (get-file-buffer todos-current-todos-file)
-         (setq todos-categories newcats)
-         (todos-update-categories-sexp))
-       (forward-line (if lower -1 -2))
-       (forward-char col)))))
+(defun todos-insertion-key-bindings (map)
+  ""
+  (dolist (c todos-insertion-commands)
+    (let* ((key "")
+          (cname (symbol-name c)))
+      (mapc (lambda (l)
+             (let ((arg (nth 0 l))
+                   (key1 (nth 1 l))
+                   (key2 (nth 2 l)))
+               (if (string-match (concat (regexp-quote arg) "\\_>") cname)
+                   (setq key (concat key key2)))
+               (if (string-match (concat (regexp-quote arg) ".+") cname)
+                   (setq key (concat key key1)))))
+           todos-insertion-commands-arg-key-list)
+      (if (string-match (concat (regexp-quote "todos-item-insert") "\\_>") cname)
+         (setq key (concat key "i")))
+      (define-key map key c))))
 
-(defun todos-lower-category ()
-  "Lower priority of category point is on in Categories buffer."
-  (interactive)
-  (todos-raise-category t))
+(defvar todos-insertion-map
+  (let ((map (make-keymap)))
+    (todos-insertion-key-bindings map)
+    map)
+  "Keymap for Todos mode insertion commands.")
 
-(defun todos-move-category ()
-  "Move current category to a different Todos file.
-If current category has archived items, also move those to the
-archive of the file moved to, creating it if it does not exist."
-  (interactive)
-  (when (or (> (length todos-categories) 1)
-           (y-or-n-p (concat "This is the only category in this file; "
-                             "moving it will also delete the file.\n"
-                             "Do you want to proceed? ")))
-    (let* ((ofile todos-current-todos-file)
-          (cat (todos-current-category))
-          (nfile (todos-read-file-name "Choose a Todos file: " nil t))
-          (archive (concat (file-name-sans-extension ofile) ".toda"))
-          (buffers (append (list ofile)
-                           (unless (zerop (todos-get-count 'archived cat))
-                             (list archive))))
-          new)
-      (dolist (buf buffers)
-       (with-current-buffer (find-file-noselect buf)
-         (widen)
-         (goto-char (point-max))
-         (let* ((beg (re-search-backward
-                      (concat "^"
-                              (regexp-quote (concat todos-category-beg cat)))
-                      nil t))
-                (end (if (re-search-forward
-                          (concat "^" (regexp-quote todos-category-beg))
-                          nil t 2)
-                         (match-beginning 0)
-                       (point-max)))
-                (content (buffer-substring-no-properties beg end))
-                (counts (cdr (assoc cat todos-categories)))
-                buffer-read-only)
-           ;; Move the category to the new file.  Also update or create
-           ;; archive file if necessary.
-           (with-current-buffer
-               (find-file-noselect
-                ;; Regenerate todos-archives in case there
-                ;; is a newly created archive.
-                (if (member buf (funcall todos-files-function t))
-                    (concat (file-name-sans-extension nfile) ".toda")
-                  nfile))
-             (let* ((nfile-short (file-name-sans-extension
-                                  (file-name-nondirectory nfile)))
-                    (prompt (concat
-                             (format "Todos file \"%s\" already has "
-                                     nfile-short)
-                             (format "the category \"%s\";\n" cat)
-                             "enter a new category name: "))
-                    buffer-read-only)
-               (widen)
-               (goto-char (point-max))
-               (insert content)
-               ;; If the file moved to has a category with the same
-               ;; name, rename the moved category.
-               (when (assoc cat todos-categories)
-                 (unless (member (file-truename (buffer-file-name))
-                                 (funcall todos-files-function t))
-                   (setq new (read-from-minibuffer prompt))
-                   (setq new (todos-validate-category-name new))))
-               ;; Replace old with new name in Todos and archive files.
-               (when new
-                 (goto-char (point-max))
-                 (re-search-backward
-                  (concat "^" (regexp-quote todos-category-beg)
-                          "\\(" (regexp-quote cat) "\\)") nil t)
-                 (replace-match new nil nil nil 1)))
-             (setq todos-categories
-                   (append todos-categories (list (cons new counts))))
-             (todos-update-categories-sexp)
-             ;; If archive was just created, save it to avoid "File <xyz> no
-             ;; longer exists!" message on invoking
-             ;; `todos-view-archived-items'.  FIXME: maybe better to save
-             ;; unconditionally?
-             (unless (file-exists-p (buffer-file-name))
-               (save-buffer))
-             (todos-category-number (or new cat))
-             (todos-category-select))
-           ;; Delete the category from the old file, and if that was the
-           ;; last category, delete the file.  Also handle archive file
-           ;; if necessary.
-           (remove-overlays beg end)
-           (delete-region beg end)
-           (goto-char (point-min))
-           ;; Put point after todos-categories sexp.
-           (forward-line)
-           (if (eobp)          ; Aside from sexp, file is empty.
-               (progn
-                 ;; Skip confirming killing the archive buffer.
-                 (set-buffer-modified-p nil)
-                 (delete-file todos-current-todos-file)
-                 (kill-buffer))
-             (setq todos-categories (delete (assoc cat todos-categories)
-                                            todos-categories))
-             (todos-update-categories-sexp)
-             (todos-category-select)))))
-      (set-window-buffer (selected-window)
-                        (set-buffer (find-file-noselect nfile)))
-      (todos-category-number (or new cat))
-      (todos-category-select))))
+;; ??FIXME: use easy-mmode-define-keymap and easy-mmode-defmap
+(defvar todos-key-bindings
+  `(
+    ;;               display
+    ("Cd"           . todos-display-categories) ;FIXME: Cs todos-show-categories?
+    ;(""            . todos-display-categories-alphabetically)
+    ("H"            . todos-highlight-item)
+    ("N"            . todos-toggle-item-numbering)
+    ("D"            . todos-toggle-display-date-time)
+    ("*"            . todos-toggle-mark-item)
+    ("C*"           . todos-mark-category)
+    ("Cu"           . todos-unmark-category)
+    ("PP"           . todos-print)
+    ("PF"           . todos-print-to-file)
+    ("v"            . todos-toggle-view-done-items)
+    ("V"            . todos-toggle-show-done-only)
+    ("Av"           . todos-view-archived-items)
+    ("As"           . todos-show-archive)
+    ("Ac"           . todos-choose-archive)
+    ("Y"            . todos-diary-items)
+    ;;(""           . todos-update-filter-files)
+    ("Fe"           . todos-edit-multiline)
+    ("Fh"           . todos-highlight-item)
+    ("Fn"           . todos-toggle-item-numbering)
+    ("Fd"           . todos-toggle-display-date-time)
+    ("Ftt"          . todos-top-priorities)
+    ("Ftm"          . todos-top-priorities-multifile)
+    ("Fts"          . todos-set-top-priorities-in-file)
+    ("Cts"          . todos-set-top-priorities-in-category)
+    ("Fyy"          . todos-diary-items)
+    ("Fym"          . todos-diary-items-multifile)
+    ("Fxx"          . todos-regexp-items)
+    ("Fxm"          . todos-regexp-items-multifile)
+    ("Fcc"          . todos-custom-items)
+    ("Fcm"          . todos-custom-items-multifile)
+    ;;(""           . todos-save-top-priorities)
+    ;;               navigation                        
+    ("f"            . todos-forward-category)
+    ("b"            . todos-backward-category)
+    ("j"            . todos-jump-to-category)
+    ("J"            . todos-jump-to-category-other-file)
+    ("n"            . todos-forward-item)
+    ("p"            . todos-backward-item)
+    ("S"            . todos-search)
+    ("X"            . todos-clear-matches)
+    ;;               editing                           
+    ("Fa"           . todos-add-file)
+    ("Ca"           . todos-add-category)
+    ("Cr"           . todos-rename-category)
+    ("Cg"           . todos-merge-category)
+    ;;(""           . todos-merge-categories)
+    ("Cm"           . todos-move-category)
+    ("Ck"           . todos-delete-category)
+    ("d"            . todos-item-done)
+    ("ee"           . todos-edit-item)
+    ("em"           . todos-edit-multiline-item)
+    ("eh"           . todos-edit-item-header)
+    ("edd"          . todos-edit-item-date)
+    ("edc"          . todos-edit-item-date-from-calendar)
+    ("edt"          . todos-edit-item-date-is-today)
+    ("et"           . todos-edit-item-time)
+    ("eyy"          . todos-edit-item-diary-inclusion)
+    ;; (""          . todos-edit-category-diary-inclusion)
+    ("eyn"          . todos-edit-item-diary-nonmarking)
+    ;;(""           . todos-edit-category-diary-nonmarking)
+    ("ec"           . todos-comment-done-item) ;FIXME: or just "c"?
+    ("i"            . ,todos-insertion-map)
+    ("k"            . todos-delete-item)
+    ("m"            . todos-move-item)
+    ("M"            . todos-move-item-to-file)
+    ;; FIXME: This binding prevents `-' from being used in a numerical prefix
+    ;; argument without typing C-u
+    ;; ("-"         . todos-raise-item-priority)
+    ("r"            . todos-raise-item-priority)
+    ;; ("+"         . todos-lower-item-priority)
+    ("l"            . todos-lower-item-priority)
+    ("#"            . todos-set-item-priority)
+    ("u"            . todos-item-undo)
+    ("Ad"           . todos-archive-done-item-or-items)  ;FIXME
+    ("AD"           . todos-archive-category-done-items) ;FIXME
+    ("Au"           . todos-unarchive-items)
+    ("AU"           . todos-unarchive-category)
+    ("s"            . todos-save)
+    ("q"            . todos-quit)
+    ([remap newline] . newline-and-indent)
+   )
+  "Alist pairing keys defined in Todos modes and their bindings.")
+
+(defvar todos-mode-map
+  (let ((map (make-keymap)))
+    ;; Don't suppress digit keys, so they can supply prefix arguments.
+    (suppress-keymap map)
+    (dolist (ck todos-key-bindings)
+      (define-key map (car ck) (cdr ck)))
+    map)
+  "Todos mode keymap.")
 
-(defun todos-merge-category ()
-  "Merge this category with chosen category in this file. The
-current category's todo and done items are appended to the chosen
-category's todo and done items, respectively, which becomes the
-current category, and the category moved from is deleted."
-  (interactive)
-  (let ((buffer-read-only nil)
-       (cat (todos-current-category))
-       (goal (todos-read-category "Category to merge to: " t)))
-    (widen)
-    ;; FIXME: check if cat has archived items and merge those too
-    (let* ((cbeg (progn
-                  (re-search-backward
-                   (concat "^" (regexp-quote todos-category-beg)) nil t)
-                  (point)))
-          (tbeg (progn (forward-line) (point)))
-          (dbeg (progn
-                  (re-search-forward
-                   (concat "^" (regexp-quote todos-category-done)) nil t)
-                  (forward-line) (point)))
-          (tend (progn (forward-line -2) (point)))
-          (cend (progn
-                  (if (re-search-forward
-                       (concat "^" (regexp-quote todos-category-beg)) nil t)
-                      (match-beginning 0)
-                    (point-max))))
-          (todo (buffer-substring-no-properties tbeg tend))
-          (done (buffer-substring-no-properties dbeg cend))
-          here)
-      (goto-char (point-min))
-      (re-search-forward
-       (concat "^" (regexp-quote (concat todos-category-beg goal))) nil t)
-      (re-search-forward
-       (concat "^" (regexp-quote todos-category-done)) nil t)
-      (forward-line -1)
-      (setq here (point))
-      (insert todo)
-      (goto-char (if (re-search-forward
-                     (concat "^" (regexp-quote todos-category-beg)) nil t)
-                    (match-beginning 0)
-                  (point-max)))
-      (insert done)
-      (remove-overlays cbeg cend)
-      (delete-region cbeg cend)
-      (todos-set-count 'todo (todos-get-count 'todo cat) goal)
-      (todos-set-count 'done (todos-get-count 'done cat) goal)
-      (setq todos-categories (delete (assoc cat todos-categories)
-                                    todos-categories))
-      (todos-update-categories-sexp)
-      (todos-category-number goal)
-      (todos-category-select)
-      ;; Put point at the start of the merged todo items.
-      ;; FIXME: what if there are no merged todo items but only done items?
-      (goto-char here))))
-      
 ;; FIXME
-(defun todos-merge-categories ()
+(easy-menu-define
+  todos-menu todos-mode-map "Todos Menu"
+  '("Todos"
+    ("Navigation"
+     ["Next Item"            todos-forward-item t]
+     ["Previous Item"        todos-backward-item t]
+     "---"
+     ["Next Category"        todos-forward-category t]
+     ["Previous Category"    todos-backward-category t]
+     ["Jump to Category"     todos-jump-to-category t]
+     ["Jump to Category in Other File" todos-jump-to-category-other-file t]
+     "---"
+     ["Search Todos File"    todos-search t]
+     ["Clear Highlighting on Search Matches" todos-category-done t])
+    ("Display"
+     ["List Current Categories" todos-display-categories t]
+     ;; ["List Categories Alphabetically" todos-display-categories-alphabetically t]
+     ["Turn Item Highlighting on/off" todos-highlight-item t]
+     ["Turn Item Numbering on/off" todos-toggle-item-numbering t]
+     ["Turn Item Time Stamp on/off" todos-toggle-display-date-time t]
+     ["View/Hide Done Items" todos-toggle-view-done-items t]
+     "---"
+     ["View Diary Items" todos-diary-items t]
+     ["View Top Priority Items" todos-top-priorities t]
+     ["View Multifile Top Priority Items" todos-top-priorities-multifile t]
+     "---"
+     ["View Archive" todos-view-archive t]
+     ["Print Category"     todos-print t])
+    ("Editing"
+     ["Insert New Item"      todos-insert-item t]
+     ["Insert Item Here"     todos-insert-item-here t]
+     ("More Insertion Commands")
+     ["Edit Item"            todos-edit-item t]
+     ["Edit Multiline Item"  todos-edit-multiline t]
+     ["Edit Item Header"     todos-edit-item-header t]
+     ["Edit Item Date"       todos-edit-item-date t]
+     ["Edit Item Time"       todos-edit-item-time t]
+     "---"
+     ["Lower Item Priority"  todos-lower-item-priority t]
+     ["Raise Item Priority"  todos-raise-item-priority t]
+     ["Set Item Priority" todos-set-item-priority t]
+     ["Move (Recategorize) Item" todos-move-item t]
+     ["Delete Item"          todos-delete-item t]
+     ["Undo Done Item" todos-item-undo t]
+     ["Mark/Unmark Item for Diary" todos-toggle-item-diary-inclusion t]
+     ["Mark/Unmark Items for Diary" todos-edit-item-diary-inclusion t]
+     ["Mark & Hide Done Item" todos-item-done t]
+     ["Archive Done Items" todos-archive-category-done-items t]
+     "---"
+     ["Add New Todos File" todos-add-file t]
+     ["Add New Category" todos-add-category t]
+     ["Delete Current Category" todos-delete-category t]
+     ["Rename Current Category" todos-rename-category t]
+     "---"
+     ["Save Todos File"      todos-save t]
+     ["Save Top Priorities"  todos-save-top-priorities t])
+    "---"
+    ["Quit"                 todos-quit t]
+    ))
+
+(defvar todos-archive-mode-map
+  (let ((map (make-sparse-keymap)))
+    (suppress-keymap map t)
+    ;; navigation commands
+    (define-key map "f" 'todos-forward-category)
+    (define-key map "b" 'todos-backward-category)
+    (define-key map "j" 'todos-jump-to-category)
+    (define-key map "n" 'todos-forward-item)
+    (define-key map "p" 'todos-backward-item)
+    ;; display commands
+    (define-key map "C" 'todos-display-categories)
+    (define-key map "H" 'todos-highlight-item)
+    (define-key map "N" 'todos-toggle-item-numbering)
+    ;; (define-key map "" 'todos-toggle-display-date-time)
+    (define-key map "P" 'todos-print)
+    (define-key map "q" 'todos-quit)
+    (define-key map "s" 'todos-save)
+    (define-key map "S" 'todos-search)
+    (define-key map "t" 'todos-show)   ;FIXME: should show same category
+    (define-key map "u" 'todos-unarchive-item)
+    (define-key map "U" 'todos-unarchive-category)
+    map)
+  "Todos Archive mode keymap.")
+
+(defvar todos-edit-mode-map
+  (let ((map (make-sparse-keymap)))
+    (define-key map "\C-x\C-q" 'todos-edit-quit)
+    (define-key map [remap newline] 'newline-and-indent)
+    map)
+  "Todos Edit mode keymap.")
+
+(defvar todos-categories-mode-map
+  (let ((map (make-sparse-keymap)))
+    (suppress-keymap map t)
+    ;; (define-key map "a" 'todos-display-categories-alphabetically)
+    (define-key map "c" 'todos-display-categories)
+    (define-key map "l" 'todos-lower-category)
+    (define-key map "+" 'todos-lower-category)
+    (define-key map "r" 'todos-raise-category)
+    (define-key map "-" 'todos-raise-category)
+    (define-key map "n" 'forward-button)
+    (define-key map "p" 'backward-button)
+    (define-key map [tab] 'forward-button)
+    (define-key map [backtab] 'backward-button)
+    (define-key map "q" 'todos-quit)
+    ;; (define-key map "A" 'todos-add-category)
+    ;; (define-key map "D" 'todos-delete-category)
+    ;; (define-key map "R" 'todos-rename-category)
+    map)
+  "Todos Categories mode keymap.")
+
+(defvar todos-filter-items-mode-map
+  (let ((map (make-keymap)))
+    (suppress-keymap map t)
+    ;; navigation commands
+    (define-key map "j" 'todos-jump-to-item)
+    (define-key map [remap newline] 'todos-jump-to-item)
+    (define-key map "n" 'todos-forward-item)
+    (define-key map "p" 'todos-backward-item)
+    (define-key map "H" 'todos-highlight-item)
+    (define-key map "N" 'todos-toggle-item-numbering)
+    (define-key map "D" 'todos-toggle-display-date-time)
+    (define-key map "P" 'todos-print)
+    (define-key map "q" 'todos-quit)
+    (define-key map "s" 'todos-save)
+    ;; (define-key map "S" 'todos-save-top-priorities)
+    ;; editing commands
+    (define-key map "l" 'todos-lower-item-priority)
+    (define-key map "r" 'todos-raise-item-priority)
+    (define-key map "#" 'todos-set-item-priority)
+    map)
+  "Todos Top Priorities mode keymap.")
+
+;; FIXME: remove when part of Emacs
+(add-to-list 'auto-mode-alist '("\\.todo\\'" . todos-mode))
+(add-to-list 'auto-mode-alist '("\\.toda\\'" . todos-archive-mode))
+
+(defun todos-modes-set-1 ()
+  ""
+  (set (make-local-variable 'font-lock-defaults) '(todos-font-lock-keywords t))
+  (set (make-local-variable 'indent-line-function) 'todos-indent)
+  (when todos-wrap-lines (funcall todos-line-wrapping-function)))
+
+(defun todos-modes-set-2 ()
+  ""
+  (add-to-invisibility-spec 'todos)
+  (setq buffer-read-only t)
+  (set (make-local-variable 'hl-line-range-function)
+       (lambda() (when (todos-item-end)
+                  (cons (todos-item-start) (todos-item-end))))))
+
+(defun todos-modes-set-3 ()
+  (set (make-local-variable 'todos-categories-full) nil)
+  ;; todos-set-categories sets todos-categories-full.
+  (set (make-local-variable 'todos-categories) (todos-set-categories))
+  (set (make-local-variable 'todos-category-number) 1)
+  (set (make-local-variable 'todos-first-visit) t)
+  (add-hook 'post-command-hook 'todos-after-find-file nil t))
+
+(put 'todos-mode 'mode-class 'special)
+
+;; Autoloading isn't needed if files are identified by auto-mode-alist
+;; ;; As calendar reads included Todos file before todos-mode is loaded.
+;; ;;;###autoload
+(define-derived-mode todos-mode special-mode "Todos" ()
+  "Major mode for displaying, navigating and editing Todo lists.
+
+\\{todos-mode-map}"
+  (easy-menu-add todos-menu)
+  (todos-modes-set-1)
+  (todos-modes-set-2)
+  (todos-modes-set-3)
+  ;; Initialize todos-current-todos-file.
+  (when (member (file-truename (buffer-file-name))
+               (funcall todos-files-function))
+    (set (make-local-variable 'todos-current-todos-file)
+        (file-truename (buffer-file-name))))
+  (set (make-local-variable 'todos-first-visit) t)
+  (set (make-local-variable 'todos-show-done-only) nil)
+  (set (make-local-variable 'todos-categoreis-with-marks) nil)
+  (when todos-show-current-file
+    (add-hook 'pre-command-hook 'todos-show-current-file nil t))
+  ;; FIXME: works more or less, but should be tied to the defcustom
+  (add-hook 'window-configuration-change-hook
+           (lambda ()
+             (setq todos-done-separator (make-string (window-width) ?_)))
+           nil t)
+  (add-hook 'kill-buffer-hook 'todos-reset-global-current-todos-file nil t))
+
+;; FIXME: need this?
+(defun todos-unload-hook ()
+  ""
+  (remove-hook 'pre-command-hook 'todos-show-current-file t)
+  (remove-hook 'post-command-hook 'todos-after-find-file t)
+  (remove-hook 'window-configuration-change-hook
+              (lambda ()
+                (setq todos-done-separator
+                      (make-string (window-width) ?_))) t)
+  (remove-hook 'kill-buffer-hook 'todos-reset-global-current-todos-file t))
+
+(put 'todos-archive-mode 'mode-class 'special)
+
+(define-derived-mode todos-archive-mode todos-mode "Todos-Arch" ()
+  "Major mode for archived Todos categories.
+
+\\{todos-archive-mode-map}"
+  (todos-modes-set-1)
+  (todos-modes-set-2)
+  (todos-modes-set-3)
+  (set (make-local-variable 'todos-current-todos-file)
+       (file-truename (buffer-file-name)))
+  (set (make-local-variable 'todos-show-done-only) t))
+
+(defun todos-mode-external-set ()
   ""
-  (interactive)
-  (let* ((cats (mapcar 'car todos-categories))
-        (goal (todos-read-category "Category to merge to: " t))
-        (prompt (format "Merge to %s (type C-g to finish)? " goal))
-        (source (let ((inhibit-quit t) l)
-                 (while (not (eq last-input-event 7))
-                   (dolist (c cats)
-                     (when (y-or-n-p prompt)
-                       (push c l)
-                       (setq cats (delete c cats))))))))
-    (widen)
-  ))
+  (set (make-local-variable 'todos-current-todos-file)
+       todos-global-current-todos-file)
+  (let ((cats (with-current-buffer (get-file-buffer todos-current-todos-file)
+               (if todos-ignore-archived-categories
+                   todos-categories-full
+                 (todos-set-categories)))))
+    (set (make-local-variable 'todos-categories) cats)))
 
-;; FIXME: make insertion options customizable per category
-;;;###autoload
-;; (defun todos-insert-item (&optional arg use-point date-type time
-;;                                 diary nonmarking)
-(defun todos-insert-item (&optional arg diary nonmarking date-type time
-                                   region-or-here)
-  "Add a new Todo item to a category.
-See the note at the end of this document string about key
-bindings and convenience commands derived from this command.
+(define-derived-mode todos-edit-mode text-mode "Todos-Ed" ()
+  "Major mode for editing multiline Todo items.
 
-With no (or nil) prefix argument ARG, add the item to the current
-category; with one prefix argument (C-u), prompt for a category
-from the current Todos file; with two prefix arguments (C-u C-u),
-first prompt for a Todos file, then a category in that file.  If
-a non-existing category is entered, ask whether to add it to the
-Todos file; if answered affirmatively, add the category and
-insert the item there.
+\\{todos-edit-mode-map}"{
+  (todos-modes-set-1)
+  (todos-mode-external-set))
 
-When argument DIARY is non-nil, this overrides the intent of the
-user option `todos-include-in-diary' for this item: if
-`todos-include-in-diary' is nil, include the item in the Fancy
-Diary display, and if it is non-nil, exclude the item from the
-Fancy Diary display.  When DIARY is nil, `todos-include-in-diary'
-has its intended effect.
+(put 'todos-categories-mode 'mode-class 'special)
 
-When the item is included in the Fancy Diary display and the
-argument NONMARKING is non-nil, this overrides the intent of the
-user option `todos-diary-nonmarking' for this item: if
-`todos-diary-nonmarking' is nil, append `diary-nonmarking-symbol'
-to the item, and if it is non-nil, omit `diary-nonmarking-symbol'.
+(define-derived-mode todos-categories-mode special-mode "Todos-Cats" ()
+  "Major mode for displaying and editing Todos categories.
 
-The argument DATE-TYPE determines the content of the item's
-mandatory date header string and how it is added:
-- If DATE-TYPE is the symbol `calendar', the Calendar pops up and
-  when the user puts the cursor on a date and hits RET, that
-  date, in the format set by `calendar-date-display-form',
-  becomes the date in the header.
-- If DATE-TYPE is the symbol `date', the header contains the date
-  in the format set by `calendar-date-display-form', with year,
-  month and day individually prompted for (month with tab
-  completion).
-- If DATE-TYPE is the symbol `dayname' the header contains a
-  weekday name instead of a date, prompted for with tab
-  completion.
-- If DATE-TYPE has any other value (including nil or none) the
-  header contains the current date (in the format set by
-  `calendar-date-display-form').
+\\{todos-categories-mode-map}"
+  (todos-mode-external-set))
 
-With non-nil argument TIME prompt for a time string; this must
-either be empty or else match `diary-time-regexp'.  If TIME is
-nil, add or omit the current time according to value of the user
-option `todos-always-add-time-string'.
+(put 'todos-filter-mode 'mode-class 'special)
 
-The argument REGION-OR-HERE determines the source and location of
-the new item:
-- If the REGION-OR-HERE is the symbol `here', prompt for the text
-  of the new item and insert it directly above the todo item at
-  point, or if point is on the empty line below the last todo
-  item, insert the new item there.  An error is signalled if
-  `todos-insert-item' is invoked with `here' outside of the
-  current category.
-- If REGION-OR-HERE is the symbol `region', use the region of the
-  current buffer as the text of the new item, depending on the
-  value of user option `todos-use-only-highlighted-region': if
-  this is non-nil, then use the region only when it is
-  highlighted; otherwise, use the region regardless of
-  highlighting.  An error is signalled if there is no region in
-  the current buffer.  Prompt for the item's priority in the
-  category (an integer between 1 and one more than the number of
-  items in the category), and insert the item accordingly.
-- If REGION-OR-HERE has any other value (in particular, nil or
-  none), prompt for the text and the item's priority, and insert
-  the item accordingly.
+(define-derived-mode todos-filter-items-mode special-mode "Todos-Fltr" ()
+  "Mode for displaying and reprioritizing top priority Todos.
 
-To facilitate using these arguments when inserting a new todo
-item, convenience commands have been defined for all admissible
-combinations (96 in all!) together with mnenomic key bindings
-based on on the name of the arguments and their order: _h_ere or
-_r_egion - _c_alendar or _d_ate or day_n_ame - _t_ime - diar_y_ -
-nonmar_k_ing.  An alternative interface for customizing key
-binding is also provided with the function
-`todos-insertion-bindings'."           ;FIXME
+\\{todos-filter-items-mode-map}"
+  (todos-modes-set-1)
+  (todos-modes-set-2))
+
+;; FIXME: need this?
+(defun todos-save ()
+  "Save the current Todos file."
+  (interactive)
+  (save-buffer)
+  ;; (if todos-save-top-priorities-too (todos-save-top-priorities))
+  )
+
+(defun todos-quit ()
+  "Exit the current Todos-related buffer.
+Depending on the specific mode, this either kills the buffer or
+buries it and restores state as needed."
+  (interactive)
+  (cond ((eq major-mode 'todos-categories-mode)
+        (kill-buffer)
+        (setq todos-descending-counts nil)
+        (todos-show))
+       ((eq major-mode 'todos-filter-items-mode)
+        (kill-buffer)
+        (todos-show))
+       ((member major-mode (list 'todos-mode 'todos-archive-mode))
+        ;; Have to write previously nonexistant archives to file.
+        (unless (file-exists-p (buffer-file-name)) (todos-save))
+        ;; FIXME: or should it save unconditionally?
+        ;; (todos-save)
+        (bury-buffer))))
+
+;; ---------------------------------------------------------------------------
+;;; Display Commands
+
+;;;###autoload
+(defun todos-show (&optional solicit-file)
+  "Visit the current Todos file and display one of its categories.
+
+With non-nil prefix argument SOLICIT-FILE ask for file to visit.
+Otherwise, the first invocation of this command in a session
+visits `todos-default-todos-file' (creating it if it does not yet
+exist); subsequent invocations from outside of Todos mode revisit
+this file or, if user option `todos-show-current-file' is
+non-nil, whichever Todos file was visited last.
+
+The category displayed on initial invocation is the first member
+of `todos-categories' for the current Todos file, on subsequent
+invocations whichever category was displayed last.  If
+`todos-display-categories-first' is non-nil, then the first
+invocation of `todos-show' displays a clickable listing of the
+categories in the current Todos file.
+
+In Todos mode just the category's unfinished todo items are shown
+by default.  The done items are hidden, but typing
+`\\[todos-toggle-view-done-items]' displays them below the todo
+items.  With non-nil user option `todos-show-with-done' both todo
+and done items are always shown on visiting a category."
   (interactive "P")
-  (let ((region (eq region-or-here 'region))
-       (here (eq region-or-here 'here)))
-    (when region
-      ;; FIXME: better to use use-region-p or region-active-p?
-      (unless (and (if todos-use-only-highlighted-region
-                      transient-mark-mode
-                    t)
-                  mark-active)
-       (error "The mark is not set now, so there is no region")))
-    (let* ((buf (current-buffer))
-          (new-item (if region
-                        ;; FIXME: or keep properties?
-                        (buffer-substring-no-properties
-                         (region-beginning) (region-end))
-                      (read-from-minibuffer "Todo item: ")))
-          (date-string (cond
-                        ((eq date-type 'date)
-                         (todos-read-date))
-                        ((eq date-type 'dayname)
-                         (todos-read-dayname))
-                        ((eq date-type 'calendar)
-                         (setq todos-date-from-calendar t)
-                         (let (calendar-view-diary-initially-flag)
-                           (calendar))
-                         (with-current-buffer "*Calendar*"
-                           (todos-set-date-from-calendar))
-                         todos-date-from-calendar)
-                        (t (calendar-date-string (calendar-current-date) t t))))
-          ;; FIXME: should TIME override `todos-always-add-time-string'?  But
-          ;; then add another option to use current time or prompt for time
-          ;; string?
-          (time-string (or (and time (todos-read-time))
-                           (and todos-always-add-time-string
-                                (substring (current-time-string) 11 16)))))
-      (setq todos-date-from-calendar nil)
-      (cond ((equal arg '(16))         ; FIXME: cf. set-mark-command
-            (todos-jump-to-category nil t)
-            (set-window-buffer
-             (selected-window)
-             (set-buffer (get-file-buffer todos-global-current-todos-file))))
-           ((equal arg '(4))           ; FIXME: just arg?
-            (todos-jump-to-category)
-            (set-window-buffer
-             (selected-window)
-             (set-buffer (get-file-buffer todos-global-current-todos-file))))
-           (t
-            (when (not (derived-mode-p 'todos-mode)) (todos-show))))
-      (let (buffer-read-only)
-       (setq new-item
-             ;; Add date, time and diary marking as required.
-             (concat (if (not (and diary (not todos-include-in-diary)))
-                         todos-nondiary-start
-                       (when (and nonmarking (not todos-diary-nonmarking))
-                         diary-nonmarking-symbol))
-                     date-string (when time-string
-                                   (concat " " time-string))
-                     (when (not (and diary (not todos-include-in-diary)))
-                       todos-nondiary-end)
-                     " " new-item))
-       ;; Indent newlines inserted by C-q C-j if nonspace char follows.
-       (setq new-item (replace-regexp-in-string
-                       "\\(\n\\)[^[:blank:]]"
-                       (concat "\n" (make-string todos-indent-to-here 32))
-                       new-item nil nil 1))
-       (if here
-           (cond ((not (eq major-mode 'todos-mode))
-                  (error "Cannot insert a todo item here outside of Todos mode"))
-                 ((not (eq buf (current-buffer)))
-                  (error "Cannot insert an item here after changing buffer"))
-                 ((or (todos-done-item-p)
-                      ;; Point on last blank line.
-                      (save-excursion (forward-line -1) (todos-done-item-p)))
-                  (error "Cannot insert a new item in the done item section"))
-                 (t
-                  (todos-insert-with-overlays new-item)))
-         (todos-set-item-priority new-item (todos-current-category) t))
-       (todos-set-count 'todo 1)
-       (if (or diary todos-include-in-diary) (todos-set-count 'diary 1))
-       (todos-update-categories-sexp)))))
+  (let ((file (cond (solicit-file
+                    (if (funcall todos-files-function)
+                        (todos-read-file-name "Choose a Todos file to visit: "
+                                              nil t)
+                      (error "There are no Todos files")))
+                   ((eq major-mode 'todos-archive-mode)
+                    ;; FIXME: should it visit same category?
+                    (concat (file-name-sans-extension todos-current-todos-file)
+                            ".todo"))
+                   (t
+                    (or todos-current-todos-file
+                        (and todos-show-current-file
+                             todos-global-current-todos-file)
+                        todos-default-todos-file
+                        (todos-add-file))))))
+    (if (and todos-first-visit todos-display-categories-first)
+       (todos-display-categories)
+      (set-window-buffer (selected-window)
+                        (set-buffer (find-file-noselect file)))
+      ;; If no Todos file exists, initialize one.
+      (if (zerop (buffer-size))
+         ;; Call with empty category name to get initial prompt.
+         (setq todos-category-number (todos-add-category "")))
+      (save-excursion (todos-category-select)))
+    (setq todos-first-visit nil)))
 
-;; FIXME: autoload when key-binding is defined in calendar.el
-(defun todos-insert-item-from-calendar ()
-  ""
+(defun todos-display-categories ()
+  "Display a table of the current file's categories and item counts.
+
+In the initial display the categories are numbered, indicating
+their current order for navigating by \\[todos-forward-category]
+and \\[todos-backward-category].  You can persistantly change the
+order of the category at point by typing \\[todos-raise-category]
+or \\[todos-lower-category].
+
+The labels above the category names and item counts are buttons,
+and clicking these changes the display: sorted by category name
+or by the respective item counts (alternately descending or
+ascending).  In these displays the categories are not numbered
+and \\[todos-raise-category] and \\[todos-lower-category] are
+disabled.  (Programmatically, the sorting is triggered by passing
+a non-nil SORTKEY argument.)
+
+In addition, the lines with the category names and item counts
+are buttonized, and pressing one of these button jumps to the
+category in Todos mode (or Todos Archive mode, for categories
+containing only archived items, provided user option
+`todos-ignore-archived-categories' is non-nil.  These categories
+are shown in `todos-archived-only' face."
   (interactive)
-  ;; FIXME: todos-current-todos-file is nil here, better to solicit Todos file?
-  ;; FIXME: t-g-c-t-f is nil if no Todos file has been visited 
-  (pop-to-buffer (file-name-nondirectory todos-global-current-todos-file))
-  (todos-show)
-  ;; FIXME: this now calls todos-set-date-from-calendar
-  (todos-insert-item t 'calendar))
+  (todos-display-categories-1)
+  (let (sortkey)
+    (todos-update-categories-display sortkey)))
 
-;; FIXME: calendar is loaded before todos
-;; (add-hook 'calendar-load-hook
-         ;; (lambda ()
-           (define-key calendar-mode-map "it" 'todos-insert-item-from-calendar);))
+;; ;; FIXME: make this toggle with todos-display-categories
+;; (defun todos-display-categories-alphabetically ()
+;;   ""
+;;   (interactive)
+;;   (todos-display-sorted 'alpha))
 
-(defvar todos-date-from-calendar nil)
-(defun todos-set-date-from-calendar ()
-  ""
-  (when todos-date-from-calendar
-    (local-set-key (kbd "RET") 'exit-recursive-edit)
-    (message "Put cursor on a date and type <return> to set it.")
-    ;; FIXME: is there a better way than recursive-edit?
-    ;; FIXME: use unwind-protect?  Check recursive-depth?
-    (recursive-edit)
-    (setq todos-date-from-calendar
-         (calendar-date-string (calendar-cursor-to-date t) t t))
-    (calendar-exit)))
+;; ;; FIXME: provide key bindings for these or delete them
+;; (defun todos-display-categories-sorted-by-todo ()
+;;   ""
+;;   (interactive)
+;;   (todos-display-sorted 'todo))
 
-(defun todos-delete-item ()
-  "Delete at least one item in this category.
+;; (defun todos-display-categories-sorted-by-diary ()
+;;   ""
+;;   (interactive)
+;;   (todos-display-sorted 'diary))
 
-If there are marked items, delete all of these; otherwise, delete
-the item at point."
+;; (defun todos-display-categories-sorted-by-done ()
+;;   ""
+;;   (interactive)
+;;   (todos-display-sorted 'done))
+
+;; (defun todos-display-categories-sorted-by-archived ()
+;;   ""
+;;   (interactive)
+;;   (todos-display-sorted 'archived))
+
+(defun todos-toggle-item-numbering ()
+  ""
   (interactive)
-  (let* ((cat (todos-current-category))
-        (marked (assoc cat todos-categories-with-marks))
-        (item (unless marked (todos-item-string)))
-        (ov (make-overlay (save-excursion (todos-item-start))
-                          (save-excursion (todos-item-end))))
-        ;; FIXME: make confirmation an option
-        (answer (if marked
-                    (y-or-n-p "Permanently delete all marked items? ")
-                  (when item
-                    (overlay-put ov 'face 'todos-search)
-                    (y-or-n-p (concat "Permanently delete this item? ")))))
-        (opoint (point))
-        buffer-read-only)
-    (when answer
-      (and marked (goto-char (point-min)))
-      (catch 'done
-       (while (not (eobp))
-         (if (or (and marked (todos-item-marked-p)) item)
-             (progn
-               (if (todos-done-item-p)
-                   (todos-set-count 'done -1)
-                 (todos-set-count 'todo -1 cat)
-                 (and (todos-diary-item-p) (todos-set-count 'diary -1)))
-               (delete-overlay ov)
-               (todos-remove-item)
-               ;; Don't leave point below last item.
-               (and item (bolp) (eolp) (< (point-min) (point-max))
-                    (todos-backward-item))
-               (when item 
-                 (throw 'done (setq item nil))))
-           (todos-forward-item))))
-      (when marked
-       (remove-overlays (point-min) (point-max) 'before-string todos-item-mark)
-       (setq todos-categories-with-marks
-             (assq-delete-all cat todos-categories-with-marks))
-       (goto-char opoint))
-      (todos-update-categories-sexp)
-      (todos-prefix-overlays))
-    (if ov (delete-overlay ov))))
+  (todos-reset-prefix 'todos-number-prefix (not todos-number-prefix)))
 
-(defun todos-edit-item ()
-  "Edit current Todo item in the minibuffer."
+(defun todos-toggle-view-done-items ()
+  "Show hidden or hide visible done items in current category."
   (interactive)
-  (when (todos-item-string)
-    (let* ((buffer-read-only)
-          (start (todos-item-start))
-          (item-beg (progn
-                      (re-search-forward
-                       (concat todos-date-string-start todos-date-pattern
-                               "\\( " diary-time-regexp "\\)?"
-                               (regexp-quote todos-nondiary-end) "?")
-                       (line-end-position) t)
-                      (1+ (- (point) start))))
-          (item (todos-item-string))
-          (multiline (> (length (split-string item "\n")) 1))
-          (opoint (point)))
-      (if multiline
-         (todos-edit-multiline)
-       (let ((new (read-string "Edit: " (cons item item-beg))))
-         (while (not (string-match
-                      (concat todos-date-string-start todos-date-pattern) new))
-           (setq new (read-from-minibuffer
-                      "Item must start with a date: " new)))
-         ;; Indent newlines inserted by C-q C-j if nonspace char follows.
-         (setq new (replace-regexp-in-string
-                    "\\(\n\\)[^[:blank:]]"
-                    (concat "\n" (make-string todos-indent-to-here 32)) new
-                    nil nil 1))
-         ;; If user moved point during editing, make sure it moves back.
-         (goto-char opoint)
-         (todos-remove-item)
-         (todos-insert-with-overlays new)
-         (move-to-column item-beg))))))
-  
-;; FIXME: run todos-check-format on exiting buffer (or check for date string
-;; and indentation)
-(defun todos-edit-multiline ()
-  "Edit current Todo item in Todos Edit mode.
-Use of newlines invokes `todos-indent' to insure compliance with
-the format of Diary entries."
+  (if (zerop (todos-get-count 'done (todos-current-category)))
+      (message "There are no done items in this category.")
+    (save-excursion
+      (goto-char (point-min))
+      (let ((todos-show-with-done (not (re-search-forward
+                                       todos-done-string-start nil t))))
+       (todos-category-select)))))
+
+(defun todos-toggle-show-done-only ()
+  "Switch between displaying only done or only todo items."
   (interactive)
-  (let ((buffer-name (generate-new-buffer-name todos-edit-buffer)))
-    (set-window-buffer
-     (selected-window)
-     (set-buffer (make-indirect-buffer
-                 (file-name-nondirectory todos-current-todos-file)
-                 buffer-name)))
-    (narrow-to-region (todos-item-start) (todos-item-end))
-    (todos-edit-mode)
-    (message "Type %s to return to Todos mode."
-            (key-description (car (where-is-internal 'todos-edit-quit))))))
+  (setq todos-show-done-only (not todos-show-done-only))
+  (todos-category-select))
 
-(defun todos-edit-quit ()
-  "Return from Todos Edit mode to Todos mode."
+(defun todos-view-archived-items ()
+  "Display the archived items of the current category.
+The buffer showing these items is in Todos Archive mode."
   (interactive)
-  (kill-buffer)
-  (todos-show))
+  (let ((cat (todos-current-category)))
+    (if (zerop (todos-get-count 'archived cat))
+       (message "There are no archived items from this category.")
+      (let* ((tfile-base (file-name-sans-extension todos-current-todos-file))
+            (afile (concat tfile-base ".toda")))
+       (set-window-buffer (selected-window) (set-buffer
+                                             (find-file-noselect afile)))
+       (todos-category-number cat)
+       (todos-jump-to-category cat)))))
 
-(defun todos-edit-item-header (&optional what)
-  "Edit date/time header of at least one item.
+(defun todos-show-archive (&optional ask)
+  "Visit the archive of the current Todos file, if it exists.
+With non-nil argument ASK prompt to choose an archive to visit;
+see `todos-choose-archive'.  The buffer showing the archive is in
+Todos Archive mode.  The first visit in a session displays the
+first category in the archive, subsequent visits return to the
+last category displayed."
+  (interactive)
+  (let* ((tfile-base (file-name-sans-extension todos-current-todos-file))
+        (afile (if ask
+                   (todos-read-file-name "Choose a Todos archive: " t t)
+                 (concat tfile-base ".toda"))))
+    (if (not (file-exists-p afile))
+       (message "There is currently no Todos archive for this file.")
+      (set-window-buffer (selected-window) (set-buffer
+                                           (find-file-noselect afile)))
+      (todos-category-select))))
 
-Interactively, ask whether to edit year, month and day or day of
-the week, as well as time.  If there are marked items, apply the
-changes to all of these; otherwise, edit just the item at point.
+(defun todos-choose-archive ()
+  "Choose an archive and visit it."
+  (interactive)
+  (todos-show-archive t))
 
-Non-interactively, argument WHAT specifies whether to edit only
-the date or only the time, or to set the date to today."
+(defun todos-highlight-item ()
+  "Toggle highlighting the todo item the cursor is on."
   (interactive)
-  (let* ((cat (todos-current-category))
-        (marked (assoc cat todos-categories-with-marks))
-        (first t)
-        ndate ntime nheader)
-    (save-excursion
-      (or (and marked (goto-char (point-min))) (todos-item-start))
-      (catch 'stop
-       (while (not (eobp))
-         (and marked
-              (while (not (todos-item-marked-p))
-                (todos-forward-item)
-                (and (eobp) (throw 'stop nil))))
-         (re-search-forward (concat todos-date-string-start "\\(?1:"
-                                    todos-date-pattern
-                                    "\\)\\(?2: " diary-time-regexp "\\)?")
-                            (line-end-position) t)
-         (let* ((odate (match-string-no-properties 1))
-                (otime (match-string-no-properties 2))
-                (buffer-read-only))
-           (if (eq what 'today)
-               (progn
-                 (setq ndate (calendar-date-string (calendar-current-date) t t))
-                 (replace-match ndate nil nil nil 1))
-             (unless (eq what 'timeonly)
-               (when first
-                 (setq ndate (if (save-match-data (string-match "[0-9]+" odate))
-                                 (if (y-or-n-p "Change date? ")
-                                     (todos-read-date)
-                                   (todos-read-dayname))
-                               (if (y-or-n-p "Change day? ")
-                                   (todos-read-dayname)
-                                 (todos-read-date)))))
-               (replace-match ndate nil nil nil 1))
-             (unless (eq what 'dateonly)
-               (when first
-                 (setq ntime (save-match-data (todos-read-time)))
-                 (when (< 0 (length ntime)) (setq ntime (concat " " ntime))))
-               (if otime
-                   (replace-match ntime nil nil nil 2)
-                 (goto-char (match-end 1))
-                 (insert ntime))))
-           (setq first nil))
-         (if marked
-             (todos-forward-item)
-           (goto-char (point-max))))))))
+  (require 'hl-line)
+  (if hl-line-mode
+      (hl-line-mode -1)
+    (hl-line-mode 1)))
+
+(defun todos-toggle-display-date-time () ;(&optional all)
+  "Hide or show date-time header of todo items.";; in current category.
+;; With non-nil prefix argument ALL do this in the whole file."
+  (interactive "P")
+  (save-excursion
+    (save-restriction
+      (goto-char (point-min))
+      (let ((ovs (overlays-in (point) (1+ (point))))
+           ov hidden)
+       (while ovs
+         (setq ov (pop ovs))
+         (if (equal (overlay-get ov 'display) "")
+             (setq ovs nil hidden t)))
+       ;; (when all
+       (widen)
+       (goto-char (point-min));)
+       (if hidden
+           (remove-overlays (point-min) (point-max) 'display "")
+         (while (not (eobp))
+           (when (re-search-forward
+                  (concat todos-date-string-start todos-date-pattern
+                          "\\( " diary-time-regexp "\\)?"
+                          (regexp-quote todos-nondiary-end) "? ")
+                  nil t)
+             (unless (save-match-data (todos-done-item-p))
+               (setq ov (make-overlay (match-beginning 0) (match-end 0) nil t))
+               (overlay-put ov 'display "")))
+           (todos-forward-item)))))))
+
+(defun todos-toggle-mark-item (&optional n all)
+  "Mark item at point if unmarked, or unmark it if marked.
+
+With a positive numerical prefix argument N, change the
+markedness of the next N items.  With non-nil argument ALL, mark
+all visible items in the category (depending on visibility, all
+todo and done items, or just todo or just done items).
+
+The mark is the character \"*\" inserted in front of the item's
+priority number or the `todos-prefix' string; if `todos-prefix'
+is \"*\", then the mark is \"@\"."
+  (interactive "p")
+  (if all (goto-char (point-min)))
+  (unless (> n 0) (setq n 1))
+  (let ((i 0))
+    (while (or (and all (not (eobp)))
+              (< i n))
+      (let* ((cat (todos-current-category))
+            (ov (todos-marked-item-p))
+            (marked (assoc cat todos-categories-with-marks)))
+       (if (and ov (not all))
+           (progn
+             (delete-overlay ov)
+             (if (= (cdr marked) 1)    ; Deleted last mark in this category.
+                 (setq todos-categories-with-marks
+                       (assq-delete-all cat todos-categories-with-marks))
+               (setcdr marked (1- (cdr marked)))))
+         (when (todos-item-start)
+           (unless (and all (todos-marked-item-p))
+             (setq ov (make-overlay (point) (point)))
+             (overlay-put ov 'before-string todos-item-mark)
+             (if marked
+                 (setcdr marked (1+ (cdr marked)))
+               (push (cons cat 1) todos-categories-with-marks))))))
+      (todos-forward-item)
+      (setq i (1+ i)))))
 
-(defun todos-edit-item-date ()
-  "Prompt For and apply changes to current item's date."
+(defun todos-mark-category ()
+  "Put the \"*\" mark on all items in this category.
+\(If `todos-prefix' is \"*\", then the mark is \"@\".)"
   (interactive)
-  (todos-edit-item-header 'dateonly))
+  (todos-toggle-mark-item 0 t))
 
-(defun todos-edit-item-date-is-today ()
-  "Set item date to today's date."
+(defun todos-unmark-category ()
+  "Remove the \"*\" mark from all items in this category.
+\(If `todos-prefix' is \"*\", then the mark is \"@\".)"
   (interactive)
-  (todos-edit-item-header 'today))
- 
-(defun todos-edit-item-time ()
-  "Prompt For and apply changes to current item's time."
+  (remove-overlays (point-min) (point-max) 'before-string todos-item-mark)
+  (setq todos-categories-with-marks
+       (delq (assoc (todos-current-category) todos-categories-with-marks)
+             todos-categories-with-marks)))
+
+(defun todos-set-top-priorities-in-file ()
+  "Set number of top priorities for this file.
+See `todos-set-top-priorities' for more details."
   (interactive)
-  (todos-edit-item-header 'timeonly))
+  (todos-set-top-priorities))
 
-(defun todos-raise-item-priority (&optional lower)
-  "Raise priority of current item by moving it up by one item.
-With non-nil argument LOWER lower item's priority."
+(defun todos-set-top-priorities-in-category ()
+  "Set number of top priorities for this category.
+See `todos-set-top-priorities' for more details."
   (interactive)
-  (unless (or (todos-done-item-p)
-             (looking-at "^$"))        ; We're between todo and done items.
-    (let (buffer-read-only)
-      (if (or (and lower
-                  (save-excursion
-                    ;; Can't lower final todo item.
-                    (todos-forward-item)
-                    (and (looking-at todos-item-start)
-                         (not (todos-done-item-p)))))
-             ;; Can't raise or lower only todo item.
-             (> (count-lines (point-min) (point)) 0))
-         (let ((item (todos-item-string))
-               (marked (todos-item-marked-p)))
-           ;; In Todos Top Priorities mode, an item's priority can be changed
-           ;; wrt items in another category, but not wrt items in the same
-           ;; category.
-           (when (eq major-mode 'todos-filter-items-mode)
-             (let* ((regexp (concat todos-date-string-start todos-date-pattern
-                                    "\\( " diary-time-regexp "\\)?"
-                                    (regexp-quote todos-nondiary-end)
-                                    "?\\(?1: \\[\\(.+:\\)?.+\\]\\)"))
-                    (cat1 (save-excursion
-                           (re-search-forward regexp nil t)
-                           (match-string 1)))
-                    (cat2 (save-excursion
-                            (if lower
-                                (todos-forward-item)
-                              (todos-backward-item))
-                            (re-search-forward regexp nil t)
-                            (match-string 1))))
-               (if (string= cat1 cat2)
-                   ;; FIXME: better message
-                   (error (concat "Cannot change item's priority in its "
-                                  "category; do this in Todos mode")))))
-           (todos-remove-item)
-           (if lower (todos-forward-item) (todos-backward-item))
-           (todos-insert-with-overlays item)
-           ;; If item was marked, retore the mark.
-           (and marked (overlay-put (make-overlay (point) (point))
-                                    'before-string todos-item-mark)))
-       (message ""))))) ;FIXME: no message ?
+  (todos-set-top-priorities t))
 
-(defun todos-lower-item-priority ()
-  "Lower priority of current item by moving it down by one item."
+(defun todos-top-priorities (&optional num)
+  "List top priorities of each category in `todos-filter-files'.
+Number of entries for each category is given by NUM, which
+defaults to `todos-show-priorities'."
+  (interactive "P")
+  (let ((arg (if num (cons 'top num) 'top))
+       (buf todos-top-priorities-buffer)
+       (file todos-current-todos-file))
+    (todos-filter-items arg)
+    (todos-special-buffer-name buf file)))
+
+(defun todos-top-priorities-multifile (&optional arg)
+  "List top priorities of each category in `todos-filter-files'.
+
+If the prefix argument ARG is a number, this is the maximum
+number of top priorities to list in each category.  If the prefix
+argument is `C-u', prompt for which files to filter and use
+`todos-show-priorities' as the number of top priorities to list
+in each category.  If the prefix argument is `C-uC-u', prompt
+both for which files to filter and for how many top priorities to
+list in each category."
+  (interactive "P")
+  (let* ((buf todos-top-priorities-buffer)
+        files
+        (pref (if (numberp arg)
+                  (cons 'top arg)
+                (setq files (if (or (consp arg)
+                                    (null todos-filter-files))
+                                (todos-multiple-files)
+                              todos-filter-files))
+                (if (equal arg '(16))
+                    (cons 'top (read-number
+                                "Enter number of top priorities to show: "
+                                todos-show-priorities))
+                  'top))))
+    (todos-filter-items pref t)
+    (todos-special-buffer-name buf files)))
+
+(defun todos-diary-items ()
+  "Display todo items for diary inclusion in this Todos file."
   (interactive)
-  (todos-raise-item-priority t))
+  (let ((buf todos-diary-items-buffer)
+       (file todos-current-todos-file))
+    (todos-filter-items 'diary)
+    (todos-special-buffer-name buf file)))
 
-;; FIXME: incorporate todos-(raise|lower)-item-priority ?
-(defun todos-set-item-priority (item cat &optional new)
-  "Set todo ITEM's priority in category CAT, moving item as needed.
-Interactively, the item and the category are the current ones,
-and the priority is a number between 1 and the number of items in
-the category.  Non-interactively with argument NEW, the lowest
-priority is one more than the number of items in CAT."
-  (interactive (list (todos-item-string) (todos-current-category)))
-  (unless (called-interactively-p t)
-    (todos-category-number cat)
-    (todos-category-select))
-  (let* ((todo (todos-get-count 'todo cat))
-        (maxnum (if new (1+ todo) todo))
-        (buffer-read-only)
-        priority candidate prompt)
-    (unless (zerop todo)
-      (while (not priority)
-       (setq candidate
-             (string-to-number (read-from-minibuffer
-                                (concat prompt
-                                        (format "Set item priority (1-%d): "
-                                                maxnum)))))
-       (setq prompt
-             (when (or (< candidate 1) (> candidate maxnum))
-               (format "Priority must be an integer between 1 and %d.\n"
-                       maxnum)))
-       (unless prompt (setq priority candidate)))
-      ;; Interactively, just relocate the item within its category.
-      (when (called-interactively-p) (todos-remove-item))
-      (goto-char (point-min))
-      (unless (= priority 1) (todos-forward-item (1- priority))))
-    (todos-insert-with-overlays item)))
+(defun todos-diary-items-multifile (&optional arg)
+  "Display todo items for diary inclusion in one or more Todos file.
+The files are those listed in `todos-filter-files'."
+  (interactive "P")
+  (let ((buf todos-diary-items-buffer)
+       (files (if (or arg (null todos-filter-files))
+                  (todos-multiple-files)
+                todos-filter-files)))
+    (todos-filter-items 'diary t)
+    (todos-special-buffer-name buf files)))
 
-;; FIXME: apply to marked items?
-(defun todos-move-item (&optional file)
-  "Move at least one todo item to another category.
+(defun todos-regexp-items ()
+  "Display todo items matching a user-entered regular expression.
+The items are those in the current Todos file."
+  (interactive)
+  (let ((buf todos-regexp-items-buffer)
+       (file todos-current-todos-file))
+    (todos-filter-items 'regexp)
+    (todos-special-buffer-name buf file)))
 
-If there are marked items, move all of these; otherwise, move
-the item at point.
+(defun todos-regexp-items-multifile (&optional arg)
+  "Display todo items matching a user-entered regular expression.
+The items are those in the files listed in `todos-filter-files'."
+  (interactive "P")
+  (let ((buf todos-regexp-items-buffer)
+       (files (if (or arg (null todos-filter-files))
+                  (todos-multiple-files)
+                todos-filter-files)))
+    (todos-filter-items 'regexp t)
+    (todos-special-buffer-name buf files)))
 
-With non-nil argument FILE, first prompt for another Todos file and
-then a category in that file to move the item or items to.
+(defun todos-custom-items ()
+  "Display todo items filtered by `todos-filter-function'.
+The items are those in the current Todos file."
+  (interactive)
+  (let ((buf todos-custom-items-buffer)
+       (file todos-current-todos-file))
+    (todos-filter-items 'custom)
+    (todos-special-buffer-name buf file)))
 
-If the chosen category is not one of the existing categories,
-then it is created and the item(s) become(s) the first
-entry/entries in that category."
+(defun todos-custom-items-multifile (&optional arg)
+  "Display todo items filtered by `todos-filter-function'.
+The items are those in the files listed in `todos-filter-files'."
+  (interactive "P")
+  (let ((buf todos-custom-items-buffer)
+       (files (if (or arg (null todos-filter-files))
+                  (todos-multiple-files)
+                todos-filter-files)))
+    (todos-filter-items 'custom t)
+    (todos-special-buffer-name buf files)))
+
+(defun todos-print (&optional to-file)
+  "Produce a printable version of the current Todos buffer.
+This converts overlays and soft line wrapping and, depending on
+the value of `todos-print-function', includes faces.  With
+non-nil argument TO-FILE write the printable version to a file;
+otherwise, send it to the default printer."
   (interactive)
-  (unless (or (todos-done-item-p)
-             (looking-at "^$"))        ; We're between todo and done items.
-    (let* ((buffer-read-only)
-          (file1 todos-current-todos-file)
-          (cat1 (todos-current-category))
-          (marked (assoc cat1 todos-categories-with-marks))
-          (num todos-category-number)
-          (item (todos-item-string))
-          (diary-item (todos-diary-item-p))
-          (omark (save-excursion (todos-item-start) (point-marker)))
-          (file2 (if file
-                     (todos-read-file-name "Choose a Todos file: " nil t)
-                   file1))
-          (count 0)
-          (count-diary 0)
-          cat2 nmark)
-      (set-buffer (find-file-noselect file2))
-      (setq cat2 (let* ((pl (if (and marked (> (cdr marked) 1)) "s" ""))
-                       (name (todos-read-category
-                              (concat "Move item" pl " to category: ")))
-                       (prompt (concat "Choose a different category than "
-                                       "the current one\n(type `"
-                                       (key-description
-                                        (car (where-is-internal
-                                              'todos-set-item-priority)))
-                                       "' to reprioritize item "
-                                       "within the same category): ")))
-                  (while (equal name cat1)
-                    (setq name (todos-read-category prompt)))
-                  name))
-      (set-buffer (get-file-buffer file1))
-      (if marked
-         (progn
-          (setq item nil)
-          (goto-char (point-min))
-          (while (not (eobp))
-            (when (todos-item-marked-p)
-              (setq item (concat item (todos-item-string) "\n"))
-              (setq count (1+ count))
-              (when (todos-diary-item-p)
-                (setq count-diary (1+ count-diary))))
-            (todos-forward-item))
-          ;; Chop off last newline.
-          (setq item (substring item 0 -1)))
-       (setq count 1)
-       (when (todos-diary-item-p) (setq count-diary 1)))
-      (set-window-buffer (selected-window)
-                        (set-buffer (find-file-noselect file2)))
-      (unless (assoc cat2 todos-categories) (todos-add-category cat2))
-      (todos-set-item-priority item cat2 t)
-      (setq nmark (point-marker))
-      (todos-set-count 'todo count)
-      (todos-set-count 'diary count-diary)
-      (todos-update-categories-sexp)
-      (with-current-buffer (get-file-buffer file1)
-       (save-excursion
-         (save-restriction
-           (widen)
-           (goto-char omark)
-           (if marked
-               (let (beg end)
-                 (setq item nil)
-                 (re-search-backward
-                  (concat "^" (regexp-quote todos-category-beg)) nil t)
-                 (forward-line)
-                 (setq beg (point))
-                 (re-search-forward
-                  (concat "^" (regexp-quote todos-category-done)) nil t)
-                 (setq end (match-beginning 0))
-                 (goto-char beg)
-                 (while (< (point) end)
-                   (if (todos-item-marked-p)
-                       (todos-remove-item)
-                     (todos-forward-item))))
-             (todos-remove-item))))
-       (todos-set-count 'todo (- count) cat1)
-       (todos-set-count 'diary (- count-diary) cat1)
-       (todos-update-categories-sexp))
-      (set-window-buffer (selected-window)
-                        (set-buffer (find-file-noselect file2)))
-      (setq todos-category-number (todos-category-number cat2))
-      (todos-category-select)
-      (goto-char nmark))))
+  (let ((buf todos-print-buffer)
+       (header (cond
+                ((eq major-mode 'todos-mode)
+                 (concat "Todos File: "
+                         (todos-short-file-name todos-current-todos-file)
+                         "\nCategory: " (todos-current-category)))
+                ((eq major-mode 'todos-filter-items-mode)
+                 "Todos Top Priorities")))
+       (prefix (propertize (concat todos-prefix " ")
+                           'face 'todos-prefix-string))
+       (num 0)
+       (fill-prefix (make-string todos-indent-to-here 32))
+       (content (buffer-string))
+       file)
+    (with-current-buffer (get-buffer-create buf)
+      (insert content)
+      (goto-char (point-min))
+      (while (not (eobp))
+       (let ((beg (point))
+             (end (save-excursion (todos-item-end))))
+         (when todos-number-prefix
+           (setq num (1+ num))
+           (setq prefix (propertize (concat (number-to-string num) " ")
+                                    'face 'todos-prefix-string)))
+         (insert prefix)
+         (fill-region beg end))
+       ;; Calling todos-forward-item infloops at todos-item-start due to
+       ;; non-overlay prefix, so search for item start instead.
+       (if (re-search-forward todos-item-start nil t)
+           (beginning-of-line)
+         (goto-char (point-max))))
+      (if (re-search-backward (concat "^" (regexp-quote todos-category-done))
+                             nil t)
+         (replace-match todos-done-separator))
+      (goto-char (point-min))
+      (insert header)
+      (newline 2)
+      (if to-file
+         (let ((file (read-file-name "Print to file: ")))
+           (funcall todos-print-function file))
+       (funcall todos-print-function)))
+    (kill-buffer buf)))
 
-(defun todos-move-item-to-file ()
-  "Move the current todo item to a category in another Todos file."
+(defun todos-print-to-file ()
+  "Save printable version of this Todos buffer to a file."
   (interactive)
-  (todos-move-item t))
+  (todos-print t))
 
-;; FIXME: apply to marked items?
-(defun todos-item-done (&optional arg)
-  "Tag this item as done and move it to category's done section.
-With prefix argument ARG prompt for a comment and append it to the
-done item."
-  (interactive "P")
-  (unless (or (todos-done-item-p)
-             (looking-at "^$"))
-    (let* ((buffer-read-only)
-          (item (todos-item-string))
-          (diary-item (todos-diary-item-p))
-          (date-string (calendar-date-string (calendar-current-date) t t))
-          (time-string (if todos-always-add-time-string ;FIXME: delete condition
-                           (concat " " (substring (current-time-string) 11 16))
-                         ""))
-          ;; FIXME: todos-nondiary-* ?
-          (done-item (concat "[" todos-done-string date-string time-string "] "
-                             item))
-          (comment (and arg (read-string "Enter a comment: "))))
-      (todos-remove-item)
-      (unless (zerop (length comment))
-       (setq done-item (concat done-item " [" todos-comment-string ": "
-                               comment "]")))
-      (save-excursion
-       (widen)
-       (re-search-forward (concat "^" (regexp-quote todos-category-done)) nil t)
-       (forward-char)
-       (todos-insert-with-overlays done-item))
-      (todos-set-count 'todo -1)
-      (todos-set-count 'done 1)
-      (and diary-item (todos-set-count 'diary -1))
-      (todos-update-categories-sexp)
-      (save-excursion (todos-category-select)))))
+(defun todos-convert-legacy-files ()
+  "Convert legacy Todo files to the current Todos format.
+The files `todo-file-do' and `todo-file-done' are converted and
+saved (the latter as a Todos Archive file) with a new name in
+`todos-files-directory'.  See also the documentation string of
+`todos-todo-mode-date-time-regexp' for further details."
+  (interactive)
+  (if (fboundp 'todo-mode)
+      (require 'todo-mode)
+    (error "Void function `todo-mode'"))
+  ;; Convert `todo-file-do'.
+  (if (file-exists-p todo-file-do)
+      (let ((default "todo-do-conv")
+           file archive-sexp)
+       (with-temp-buffer
+         (insert-file-contents todo-file-do)
+         (let ((end (search-forward ")" (line-end-position) t))
+               (beg (search-backward "(" (line-beginning-position) t)))
+           (setq todo-categories
+                 (read (buffer-substring-no-properties beg end))))
+         (todo-mode)
+         (delete-region (line-beginning-position) (1+ (line-end-position)))
+         (while (not (eobp))
+           (cond
+            ((looking-at (regexp-quote (concat todo-prefix todo-category-beg)))
+             (replace-match todos-category-beg))
+            ((looking-at (regexp-quote todo-category-end))
+             (replace-match ""))
+            ((looking-at (regexp-quote (concat todo-prefix " "
+                                               todo-category-sep)))
+             (replace-match todos-category-done))
+            ((looking-at (concat (regexp-quote todo-prefix) " "
+                                 todos-todo-mode-date-time-regexp " "
+                                 (regexp-quote todo-initials) ":"))
+             (todos-convert-legacy-date-time)))
+           (forward-line))
+         (setq file (concat todos-files-directory
+                            (read-string
+                             (format "Save file as (default \"%s\"): " default)
+                             nil nil default)
+                            ".todo"))
+         (write-region (point-min) (point-max) file nil 'nomessage nil t))
+       (with-temp-buffer
+         (insert-file-contents file)
+         (let ((todos-categories (todos-make-categories-list t)))
+           (todos-update-categories-sexp))
+         (write-region (point-min) (point-max) file nil 'nomessage))
+       ;; Convert `todo-file-done'.
+       (when (file-exists-p todo-file-done)
+         (with-temp-buffer
+           (insert-file-contents todo-file-done)
+           (let ((beg (make-marker))
+                 (end (make-marker))
+                 cat cats comment item)
+             (while (not (eobp))
+               (when (looking-at todos-todo-mode-date-time-regexp)
+                 (set-marker beg (point))
+                 (todos-convert-legacy-date-time)
+                 (set-marker end (point))
+                 (goto-char beg)
+                 (insert "[" todos-done-string)
+                 (goto-char end)
+                 (insert "]")
+                 (forward-char)
+                 (when (looking-at todos-todo-mode-date-time-regexp)
+                   (todos-convert-legacy-date-time))
+                 (when (looking-at (concat " " (regexp-quote todo-initials) ":"))
+                   (replace-match "")))
+               (if (re-search-forward
+                    (concat "^" todos-todo-mode-date-time-regexp) nil t)
+                   (goto-char (match-beginning 0))
+                 (goto-char (point-max)))
+               (backward-char)
+               (when (looking-back "\\[\\([^][]+\\)\\]")
+                 (setq cat (match-string 1))
+                 (goto-char (match-beginning 0))
+                 (replace-match ""))
+               ;; If the item ends with a non-comment parenthesis not
+               ;; followed by a period, we lose (but we inherit that problem
+               ;; from todo-mode.el).
+               (when (looking-back "(\\(.*\\)) ")
+                 (setq comment (match-string 1))
+                 (replace-match "")
+                 (insert "[" todos-comment-string ": " comment "]"))
+               (set-marker end (point))
+               (if (member cat cats)
+                   ;; If item is already in its category, leave it there.
+                   (unless (save-excursion
+                             (re-search-backward
+                              (concat "^" (regexp-quote todos-category-beg)
+                                      "\\(.*\\)$") nil t)
+                             (string= (match-string 1) cat))
+                     ;; Else move it to its category.
+                     (setq item (buffer-substring-no-properties beg end))
+                     (delete-region beg (1+ end))
+                     (set-marker beg (point))
+                     (re-search-backward
+                      (concat "^" (regexp-quote (concat todos-category-beg cat)))
+                      nil t)
+                     (forward-line)
+                     (if (re-search-forward
+                          (concat "^" (regexp-quote todos-category-beg)
+                                  "\\(.*\\)$") nil t)
+                         (progn (goto-char (match-beginning 0))
+                                (newline)
+                                (forward-line -1))
+                       (goto-char (point-max)))
+                     (insert item "\n")
+                     (goto-char beg))
+                 (push cat cats)
+                 (goto-char beg)
+                 (insert todos-category-beg cat "\n\n" todos-category-done "\n"))
+               (forward-line))
+             (set-marker beg nil)
+             (set-marker end nil))
+           (setq file (concat (file-name-sans-extension file) ".toda"))
+           (write-region (point-min) (point-max) file nil 'nomessage nil t))
+         (with-temp-buffer
+           (insert-file-contents file)
+           (let ((todos-categories (todos-make-categories-list t)))
+             (todos-update-categories-sexp))
+           (write-region (point-min) (point-max) file nil 'nomessage)
+           (setq archive-sexp (read (buffer-substring-no-properties
+                                     (line-beginning-position)
+                                     (line-end-position)))))
+         (setq file (concat (file-name-sans-extension file) ".todo"))
+         ;; Update categories sexp of converted Todos file again, adding
+         ;; counts of archived items.
+         (with-temp-buffer
+           (insert-file-contents file)
+           (let ((sexp (read (buffer-substring-no-properties
+                              (line-beginning-position)
+                              (line-end-position)))))
+             (dolist (cat sexp)
+               (let ((archive-cat (assoc (car cat) archive-sexp)))
+                 (if archive-cat
+                     (aset (cdr cat) 3 (aref (cdr archive-cat) 2)))))
+             (delete-region (line-beginning-position) (line-end-position))
+             (prin1 sexp (current-buffer)))
+           (write-region (point-min) (point-max) file nil 'nomessage)))
+         (todos-reevaluate-defcustoms)
+       (message "Format conversion done."))
+    (error "No legacy Todo file exists")))
 
-(defun todos-comment-done-item ()
-  "Add a comment to this done item."
+;; ---------------------------------------------------------------------------
+;;; Navigation Commands
+
+(defun todos-forward-category (&optional back)
+  "Visit the numerically next category in this Todos file.
+If the current category is the highest numbered, visit the first
+category.  With non-nil argument BACK, visit the numerically
+previous category (the highest numbered one, if the current
+category is the first)."
   (interactive)
-  (when (todos-done-item-p)
-    (let ((comment (read-string "Enter a comment: "))
-         buffer-read-only)
-      (todos-item-end)
-      (insert " [" todos-comment-string ": " comment "]"))))
+  (setq todos-category-number
+        (1+ (mod (- todos-category-number (if back 2 0))
+                (length todos-categories))))
+  (todos-category-select)
+  (goto-char (point-min)))
 
-;; FIXME: implement this or done item editing?
-(defun todos-uncomment-done-item ()
-  ""
-  )
+(defun todos-backward-category ()
+  "Visit the numerically previous category in this Todos file.
+If the current category is the highest numbered, visit the first
+category."
+  (interactive)
+  (todos-forward-category t))
 
-;; FIXME: delete comment from restored item or just leave it up to user?
-(defun todos-item-undo ()
-  "Restore this done item to the todo section of this category."
+(defun todos-jump-to-category (&optional cat other-file)
+  "Jump to a category in this or another Todos file.
+
+Programmatically, optional argument CAT provides the category
+name.  When nil (as in interactive calls), prompt for the
+category, with TAB completion on existing categories.  If a
+non-existing category name is entered, ask whether to add a new
+category with this name; if affirmed, add it, then jump to that
+category.  With non-nil argument OTHER-FILE, prompt for a Todos
+file, otherwise jump within the current Todos file."
   (interactive)
-  (when (todos-done-item-p)
-    (let* ((buffer-read-only)
-          (done-item (todos-item-string))
-          (opoint (point))
-          (orig-mrk (progn (todos-item-start) (point-marker)))
-          ;; Find the end of the date string added upon making item done.
-          (start (search-forward "] "))
-          (item (buffer-substring start (todos-item-end)))
-          undone)
-      (todos-remove-item)
-      ;; If user cancels before setting new priority, then restore everything.
-      (unwind-protect
-         (progn
-           (todos-set-item-priority item (todos-current-category) t)
-           (setq undone t)
-           (todos-set-count 'todo 1)
-           (todos-set-count 'done -1)
-           (and (todos-diary-item-p) (todos-set-count 'diary 1))
-           (todos-update-categories-sexp))
-       (unless undone
-         (widen)
-         (goto-char orig-mrk)
-         (todos-insert-with-overlays done-item)
-         (let ((todos-show-with-done t))
+  (let ((file (or (and other-file
+                      (todos-read-file-name "Choose a Todos file: " nil t))
+                 ;; Jump to archived-only Categories from Todos Categories mode.
+                 (and cat
+                      todos-ignore-archived-categories
+                      (zerop (todos-get-count 'todo cat))
+                      (zerop (todos-get-count 'done cat))
+                      (not (zerop (todos-get-count 'archived cat)))
+                      (concat (file-name-sans-extension
+                               todos-current-todos-file) ".toda"))
+                 todos-current-todos-file
+                 ;; If invoked from outside of Todos mode before todos-show...
+                 todos-default-todos-file)))
+       (with-current-buffer (find-file-noselect file)
+         (and other-file (setq todos-current-todos-file file))
+         (let ((category (or (and (assoc cat todos-categories) cat)
+                             (todos-read-category "Jump to category: "))))
+           ;; Clean up after selecting category in Todos Categories mode.
+           (if (string= (buffer-name) todos-categories-buffer)
+               (kill-buffer))
+           (if (or cat other-file)
+               (set-window-buffer (selected-window)
+                                  (set-buffer (get-file-buffer file))))
+           (unless todos-global-current-todos-file
+             (setq todos-global-current-todos-file todos-current-todos-file))
+           (todos-category-number category)
+           (if (> todos-category-number (length todos-categories))
+               (setq todos-category-number (todos-add-category category)))
            (todos-category-select)
-           (goto-char opoint)))
-       (set-marker orig-mrk nil)))))
-
-(defun todos-archive-done-item-or-items (&optional all)
-  "Archive at least one done item in this category.
+           (goto-char (point-min))))))
 
-If there are marked done items (and no marked todo items),
-archive all of these; otherwise, with non-nil argument ALL,
-archive all done items in this category; otherwise, archive the
-done item at point.
+(defun todos-jump-to-category-other-file ()
+  "Jump to a category in another Todos file.
+The category is chosen by prompt, with TAB completion."
+  (interactive)
+  (todos-jump-to-category nil t))
 
-If the archive of this file does not exist, it is created.  If
-this category does not exist in the archive, it is created."
+(defun todos-jump-to-item ()
+  "Jump to the file and category of the filtered item at point."
   (interactive)
-  (when (not (member (buffer-file-name) (funcall todos-files-function t)))
-    (if (and all (zerop (todos-get-count 'done cat)))
-       (message "No done items in this category")
-      (catch 'end
-       (let* ((cat (todos-current-category))
-              (tbuf (current-buffer))
-              (marked (assoc cat todos-categories-with-marks))
-              (afile (concat (file-name-sans-extension
-                              todos-current-todos-file) ".toda"))
-              (archive (if (file-exists-p afile)
-                           (find-file-noselect afile t)
-                         (progn
-                           ;; todos-add-category requires an exisiting file...
-                           (with-current-buffer (get-buffer-create afile)
-                             (erase-buffer)
-                             (write-region (point-min) (point-max) afile
-                                           nil 'nomessage nil t)))
-                         ;; ...but the file still lacks a categories sexp, so
-                         ;; visiting the file would barf on todos-set-categories,
-                         ;; hence we just return the buffer.
-                         (get-buffer afile)))
-              (item (and (todos-done-item-p) (concat (todos-item-string) "\n")))
-              (count 0)
-              marked-items beg end all-done
-              buffer-read-only)
-         (cond
-          (marked
-           (save-excursion
-             (goto-char (point-min))
-             (while (not (eobp))
-               (if (todos-item-marked-p)
-                   (if (not (todos-done-item-p))
-                       (throw 'end (message "Only done items can be archived"))
-                     (concat marked-items (todos-item-string) "\n")
-                     (setq count (1+ count)))
-                 (todos-forward-item)))))
-          (all
-           (if (y-or-n-p "Archive all done items in this category? ")
-               (save-excursion
-                 (save-restriction
-                   (goto-char (point-min))
-                   (widen)
-                   (setq beg (progn
-                               (re-search-forward todos-done-string-start nil t)
-                               (match-beginning 0))
-                         end (if (re-search-forward
-                                  (concat "^" (regexp-quote todos-category-beg))
-                                  nil t)
-                                 (match-beginning 0)
-                               (point-max))
-                         all-done (buffer-substring beg end)
-                         count (todos-get-count 'done))))
-             (throw 'end nil))))
-         (when (or marked all item)
-           (with-current-buffer archive
-             (let ((current todos-global-current-todos-file)
-                   (buffer-read-only))
-               (widen)
-               (goto-char (point-min))
-               (if (progn
-                     (re-search-forward
-                      (concat "^" (regexp-quote (concat todos-category-beg cat)))
-                      nil t)
-                     (re-search-forward (regexp-quote todos-category-done) nil t))
-                   (forward-char)
-                 ;; todos-add-category uses t-c-t-f, so temporarily set it.
-                 (setq todos-current-todos-file afile)
-                 (todos-add-category cat)
-                 (goto-char (point-max)))
-               (insert (cond (marked marked-items)
-                             (all all-done)
-                             (item)))
-               (todos-set-count 'done (if (or marked all) count 1))
-               (todos-update-categories-sexp)
-               ;; Save to file now (using write-region in order not to visit
-               ;; afile) so we can visit it later with todos-view-archived-items
-               ;; or todos-show-archive.
-               (write-region nil nil afile)
-               (setq todos-current-todos-file current)))
-           (with-current-buffer tbuf
-             (cond ((or marked item)
-                    (and marked (goto-char (point-min)))
-                    (catch 'done
-                      (while (not (eobp))
-                        (if (or (and marked (todos-item-marked-p)) item)
-                            (progn
-                              (todos-remove-item)
-                              (todos-set-count 'done -1)
-                              (todos-set-count 'archived 1)
-                              ;; Don't leave point below last item.
-                              (and item (bolp) (eolp) (< (point-min) (point-max))
-                                   (todos-backward-item))
-                              (when item 
-                                (throw 'done (setq item nil))))
-                          (todos-forward-item)))))
-                   (all
-                    (remove-overlays beg end)
-                    (delete-region beg end)
-                    (todos-set-count 'done (- count))
-                    (todos-set-count 'archived count)))
-             (when marked
-               (remove-overlays (point-min) (point-max)
-                                'before-string todos-item-mark)
-               (setq todos-categories-with-marks
-                     (assq-delete-all cat todos-categories-with-marks))
-               (goto-char opoint))
-             (todos-update-categories-sexp)
-             (todos-prefix-overlays)
-             ;; FIXME: Heisenbug: item displays mark -- but not when edebugging
-             (remove-overlays (point-min) (point-max)
-                              'before-string todos-item-mark)))
-         (display-buffer (find-file-noselect afile) t)
-         ;; FIXME: how to avoid switch-to-buffer and still get tbuf above
-         ;; afile?  What about pop-to-buffer-same-window in recent trunk?
-         (switch-to-buffer tbuf))))))
+  (let ((str (todos-item-string))
+       (buf (current-buffer))
+       cat file beg)
+    (string-match (concat todos-date-string-start todos-date-pattern
+                         "\\(?: " diary-time-regexp "\\)?"
+                         (regexp-quote todos-nondiary-end) "?"
+                         "\\(?3: \\[\\(?2:.*:\\)?\\(?1:.*\\)\\]\\).*$") str)
+    (setq cat (match-string 1 str))
+    (setq file (match-string 2 str))
+    (setq str (replace-match "" nil nil str 3))
+    (setq file (if file
+                  (concat todos-files-directory (substring file 0 -1) ".todo")
+                todos-global-current-todos-file))
+    (find-file-noselect file)
+    (with-current-buffer (get-file-buffer file)
+      (widen)
+      (goto-char (point-min))
+      (re-search-forward
+       (concat "^" (regexp-quote (concat todos-category-beg cat))) nil t)
+      (search-forward str)
+      (setq beg (match-beginning 0)))
+    (kill-buffer buf)
+    (set-window-buffer (selected-window) (set-buffer (get-file-buffer file)))
+    (setq todos-current-todos-file file)
+    (setq todos-category-number (todos-category-number cat))
+    (todos-category-select)
+    (goto-char beg)))
+
+;; FIXME ? disallow prefix arg value < 1 (re-search-* allows these)
+(defun todos-forward-item (&optional count)
+  "Move point down to start of item with next lower priority.
+With numerical prefix COUNT, move point COUNT items downward,"
+  (interactive "P")
+  (let* ((not-done (not (or (todos-done-item-p) (looking-at "^$"))))
+        (start (line-end-position)))
+    (goto-char start)
+    (if (re-search-forward todos-item-start nil t (or count 1))
+       (goto-char (match-beginning 0))
+      (goto-char (point-max)))
+    ;; If points advances by one from a todo to a done item, go back to the
+    ;; space above todos-done-separator, since that is a legitimate place to
+    ;; insert an item.  But skip this space if count > 1, since that should
+    ;; only stop on an item (FIXME: or not?)
+    (when (and not-done (todos-done-item-p))
+      (if (or (not count) (= count 1))
+         (re-search-backward "^$" start t)))))
 
-(defun todos-archive-category-done-items ()
-  "Move all done items in this category to its archive."
+(defun todos-backward-item (&optional count)
+  "Move point up to start of item with next higher priority.
+With numerical prefix COUNT, move point COUNT items upward,"
+  (interactive "P")
+  (let* ((done (todos-done-item-p)))
+    ;; FIXME ? this moves to bob if on the first item (but so does previous-line)
+    (todos-item-start)
+    (unless (bobp)
+      (re-search-backward todos-item-start nil t (or count 1)))
+    ;; If points advances by one from a done to a todo item, go back to the
+    ;; space above todos-done-separator, since that is a legitimate place to
+    ;; insert an item.  But skip this space if count > 1, since that should
+    ;; only stop on an item (FIXME: or not?)
+    (when (and done (not (todos-done-item-p))
+              (or (not count) (= count 1)))
+      (re-search-forward (concat "^" (regexp-quote todos-category-done)) nil t)
+      (forward-line -1))))
+
+;; FIXME: (i) Extend search to other Todos files. (ii) Allow navigating among
+;; hits.
+(defun todos-search ()
+  "Search for a regular expression in this Todos file.
+The search runs through the whole file and encompasses all and
+only todo and done items; it excludes category names.  Multiple
+matches are shown sequentially, highlighted in `todos-search'
+face."
   (interactive)
-  (todos-archive-done-item-or-items t))
+  (let ((regex (read-from-minibuffer "Enter a search string (regexp): "))
+       (opoint (point))
+       matches match cat in-done ov mlen msg)
+    (widen)
+    (goto-char (point-min))
+    (while (not (eobp))
+      (setq match (re-search-forward regex nil t))
+      (goto-char (line-beginning-position))
+      (unless (or (equal (point) 1)
+                 (looking-at (concat "^" (regexp-quote todos-category-beg))))
+       (if match (push match matches)))
+      (forward-line))
+    (setq matches (reverse matches))
+    (if matches
+       (catch 'stop
+         (while matches
+           (setq match (pop matches))
+           (goto-char match)
+           (todos-item-start)
+           (when (looking-at todos-done-string-start)
+             (setq in-done t))
+           (re-search-backward (concat "^" (regexp-quote todos-category-beg)
+                                       "\\(.*\\)\n") nil t)
+           (setq cat (match-string-no-properties 1))
+           (todos-category-number cat)
+           (todos-category-select)
+           (if in-done
+               (unless todos-show-with-done (todos-toggle-view-done-items)))
+           (goto-char match)
+           (setq ov (make-overlay (- (point) (length regex)) (point)))
+           (overlay-put ov 'face 'todos-search)
+           (when matches
+             (setq mlen (length matches))
+             (if (y-or-n-p
+                  (if (> mlen 1)
+                      (format "There are %d more matches; go to next match? "
+                              mlen)
+                    "There is one more match; go to it? "))
+                 (widen)
+               (throw 'stop (setq msg (if (> mlen 1)
+                                          (format "There are %d more matches."
+                                                  mlen)
+                                        "There is one more match."))))))
+         (setq msg "There are no more matches."))
+      (todos-category-select)
+      (goto-char opoint)
+      (message "No match for \"%s\"" regex))
+    (when msg
+      (if (y-or-n-p (concat msg "\nUnhighlight matches? "))
+         (todos-clear-matches)
+       (message "You can unhighlight the matches later by typing %s"
+                (key-description (car (where-is-internal
+                                       'todos-clear-matches))))))))
 
-(defun todos-unarchive-items (&optional all)
-  "Unarchive at least one item in this archive category.
+(defun todos-clear-matches ()
+  "Remove highlighting on matches found by todos-search."
+  (interactive)
+  (remove-overlays 1 (1+ (buffer-size)) 'face 'todos-search))
 
-If there are marked items, unarchive all of these; otherwise,
-with non-nil argument ALL, unarchive all items in this category;
-otherwise, unarchive the item at point.
+;; ---------------------------------------------------------------------------
+;;; Editing Commands
 
-Unarchived items are restored as done items to the corresponding
-category in the Todos file, inserted at the end of done section.
-If all items in the archive category were restored, the category
-is deleted from the archive.  If this was the only category in the
-archive, the archive file is deleted."
+;; FIXME: autoload?
+;; FIXME: should there also be command todos-delete-file or is it enough to
+;; delete empty file on deleting last category with todos-delete-category?
+(defun todos-add-file ()
+  "Name and add a new Todos file.
+Interactively, prompt for a category and display it.
+Noninteractively, return the name of the new file."
   (interactive)
-  (when (member (buffer-file-name) (funcall todos-files-function t))
-    (catch 'end
-      (let* ((buffer-read-only nil)
-            (tbuf (find-file-noselect
-                   (concat (file-name-sans-extension todos-current-todos-file)
-                           ".todo") t))
-            (cat (todos-current-category))
-            (marked (assoc cat todos-categories-with-marks))
-            (item (concat (todos-item-string) "\n"))
-            (all-items (buffer-substring (point-min) (point-max)))
-            (all-count (todos-get-count 'done))
-            marked-items marked-count)
-       (save-excursion
-         (goto-char (point-min))
-         (while (not (eobp))
-           (when (todos-item-marked-p)
-             (concat marked-items (todos-item-string) "\n")
-             (setq marked-count (1+ marked-count)))
-           (todos-forward-item)))
-       ;; Restore items to end of category's done section and update counts.
-       (with-current-buffer tbuf
+  (let ((default-file (if todos-default-todos-file
+                         (todos-short-file-name todos-default-todos-file)))
+       (prompt (concat "Enter name of new Todos file "
+                       "(TAB or SPC to see current names): "))
+       file shortname)
+    (setq file (todos-read-file-name prompt));))
+    (setq shortname (todos-short-file-name file))
+    (with-current-buffer (get-buffer-create file)
+      (erase-buffer)
+      (write-region (point-min) (point-max) file nil 'nomessage nil t)
+      (kill-buffer file))
+    (todos-reevaluate-defcustoms)
+    (if (called-interactively-p)
+       (progn
+         (setq todos-current-todos-file file)
+         (todos-show))
+      file)))
+
+(defun todos-add-category (&optional cat)
+  "Add a new category to the current Todos file.
+Called interactively, prompt for category name, then visit the
+category in Todos mode.  Non-interactively, argument CAT provides
+the category name, which is also the return value."
+  (interactive)
+  (let* ((buffer-read-only)
+        ;; FIXME: check against todos-archive-done-item-or-items with empty file
+        (buf (find-file-noselect todos-current-todos-file t))
+        ;; (buf (get-file-buffer todos-current-todos-file))
+        (num (1+ (length todos-categories)))
+        (counts (make-vector 4 0)))    ; [todo diary done archived]
+    (unless (zerop (buffer-size buf))
+      (and (null todos-categories)
+          (error "Error in %s: File is non-empty but contains no category"
+                 todos-current-todos-file)))
+    (unless cat (setq cat (read-from-minibuffer "Enter new category name: ")))
+    (with-current-buffer buf
+      (setq cat (todos-validate-name cat 'category))
+      (setq todos-categories (append todos-categories (list (cons cat counts))))
+      (if todos-categories-full
+         (setq todos-categories-full (append todos-categories-full
+                                             (list (cons cat counts)))))
+      (widen)
+      (goto-char (point-max))
+      (save-excursion                  ; Save point for todos-category-select.
+       (insert todos-category-beg cat "\n\n" todos-category-done "\n"))
+      (todos-update-categories-sexp)
+      ;; If called by command, display the newly added category, else return
+      ;; the category number to the caller.
+      (if (called-interactively-p 'any)          ; FIXME?
+         (progn
+           (setq todos-category-number num)
+           (todos-category-select))
+       num))))
+
+(defun todos-rename-category ()
+  "Rename current Todos category.
+If this file has an archive containing this category, rename the
+category there as well."
+  (interactive)
+  (let* ((cat (todos-current-category))
+        (new (read-from-minibuffer (format "Rename category \"%s\" to: " cat))))
+    (setq new (todos-validate-name new 'category))
+    (let* ((ofile todos-current-todos-file)
+          (archive (concat (file-name-sans-extension ofile) ".toda"))
+          (buffers (append (list ofile)
+                           (unless (zerop (todos-get-count 'archived cat))
+                             (list archive)))))
+      (dolist (buf buffers)
+       (with-current-buffer (find-file-noselect buf)
          (let (buffer-read-only)
-           (widen)
-           (goto-char (point-min))
-           (re-search-forward (concat "^" (regexp-quote
-                                           (concat todos-category-beg cat)))
-                              nil t)
-           (if (re-search-forward (concat "^" (regexp-quote todos-category-beg))
+           (setq todos-categories (todos-set-categories))
+           (save-excursion
+             (save-restriction
+               (setcar (assoc cat todos-categories) new)
+               (widen)
+               (goto-char (point-min))
+               (todos-update-categories-sexp)
+               (re-search-forward (concat (regexp-quote todos-category-beg)
+                                          "\\(" (regexp-quote cat) "\\)\n")
                                   nil t)
-               (goto-char (match-beginning 0))
-             (goto-char (point-max)))
-           (cond (marked
-                  (insert marked-items)
-                  (todos-set-count 'done marked-count)
-                  (todos-set-count 'archived (- marked-count)))
-                 (all
-                  (if (y-or-n-p (concat "Restore this category's items "
-                                        "to Todos file as done items "
-                                        "and delete this category? "))
-                      (progn (insert all-items)
-                             (todos-set-count 'done all-count)
-                             (todos-set-count 'archived (- all-count)))
-                    (throw 'end nil)))
-                 (t
-                  (insert item)
-                  (todos-set-count 'done 1)
-                  (todos-set-count 'archived -1)))
-           (todos-update-categories-sexp)))
-       ;; Delete restored items from archive.
-       (cond ((or marked item)
-              (and marked (goto-char (point-min)))
-              (catch 'done
-                (while (not (eobp))
-                  (if (or (and marked (todos-item-marked-p)) item)
-                      (progn
-                        (todos-remove-item)
-                        (todos-set-count 'done -1)
-                        ;; Don't leave point below last item.
-                        (and item (bolp) (eolp) (< (point-min) (point-max))
-                             (todos-backward-item))
-                        (when item 
-                          (throw 'done (setq item nil))))
-                    (todos-forward-item)))))
-             (all
-              (remove-overlays (point-min) (point-max))
-              (delete-region (point-min) (point-max))
-              (todos-set-count 'done (- all-count))))
-       ;; If that was the last category in the archive, delete the whole file.
-       (if (= (length todos-categories) 1)
-           (progn
-             (delete-file todos-current-todos-file)
-             ;; Don't bother confirming killing the archive buffer.
-             (set-buffer-modified-p nil)
-             (kill-buffer))
-         ;; Otherwise, if the archive category is now empty, delete it.
-         (when (eq (point-min) (point-max))
+               (replace-match new t t nil 1)))))))
+    ;; FIXME: use force-mode-line-update instead?
+    (setq mode-line-buffer-identification
+         (funcall todos-mode-line-function new)))
+  (save-excursion (todos-category-select)))
+
+(defun todos-delete-category (&optional arg)
+  "Delete current Todos category provided it is empty.
+With ARG non-nil delete the category unconditionally,
+i.e. including all existing todo and done items."
+  (interactive "P")
+  (let* ((cat (todos-current-category))
+        (todo (todos-get-count 'todo cat))
+        (done (todos-get-count 'done cat))
+        (archived (todos-get-count 'archived cat)))
+    (when (or (> (length todos-categories) 1)
+             (y-or-n-p (concat "This is the only category in this file; "
+                               "deleting it will also delete the file.\n"
+                               "Do you want to proceed? ")))
+      (if (and (not arg)
+              (or (> todo 0) (> done 0)))
+         (message "To delete a non-empty category, type C-u %s."
+                  (key-description
+                   (car (where-is-internal 'todos-delete-category))))
+       (when (yes-or-no-p (concat "Permanently remove category \"" cat
+                                  "\"" (and arg " and all its entries") "? "))
+         (when (and archived
+                    (y-or-n-p (concat "This category has archived items; "
+                                      "the archived category will remain\n"
+                                      "after deleting the todo category.  "
+                                      "Do you still want to delete it\n"
+                                      "(see 'todos-ignore-archived-categories' "
+                                      "for another option)? ")))
            (widen)
-           (let ((beg (re-search-backward
-                       (concat "^" (regexp-quote todos-category-beg) cat)
-                       nil t))
+           (let ((buffer-read-only)
+                 (beg (re-search-backward
+                       (concat "^" (regexp-quote (concat todos-category-beg cat))
+                               "\n") nil t))
                  (end (if (re-search-forward
-                           (concat "^" (regexp-quote todos-category-beg))
-                           nil t 2)
-                          (match-beginning 0)
+                           (concat "\n\\(" (regexp-quote todos-category-beg)
+                                   ".*\n\\)") nil t)
+                          (match-beginning 1)
                         (point-max))))
              (remove-overlays beg end)
              (delete-region beg end)
-             (setq todos-categories (delete (assoc cat todos-categories)
-                                            todos-categories))
-             (todos-update-categories-sexp))))
-       ;; Visit category in Todos file and show restored done items.
-       (let ((tfile (buffer-file-name tbuf))
-             (todos-show-with-done t))
-         (set-window-buffer (selected-window)
-                            (set-buffer (find-file-noselect tfile)))
-         (todos-category-number cat)
-         (todos-show)
-         (message "Items unarchived."))))))
-
-(defun todos-unarchive-category ()
-  "Unarchive all items in this category.  See `todos-unarchive-items'."
-  (interactive)
-  (todos-unarchive-items t))
-
-(defun todos-toggle-diary-inclusion (&optional all)
-  "Toggle diary status of one or more todo items in this category.
-
-If a candidate item is marked with `todos-nondiary-marker',
-remove this marker; otherwise, insert it.
-
-With non-nil argument ALL toggle the diary status of all todo
-items in this category; otherwise, if there are marked todo
-items, toggle the diary status of all and only these, otherwise
-toggle the diary status of the item at point.  "
-  (interactive)
-  (let ((marked (assoc (todos-current-category)
-                      todos-categories-with-marks)))
-    (catch 'stop
-      (save-excursion
-       (save-restriction
-         (when (or marked all) (goto-char (point-min)))
-         (while (not (eobp))
-           (if (todos-done-item-p)
-               (throw 'stop (message "Done items cannot be changed"))
-             (unless (and marked (not (todos-item-marked-p)))
-               (save-excursion
-                 (let* ((buffer-read-only)
-                        (beg (todos-item-start))
-                        (lim (save-excursion (todos-item-end)))
-                        (end (save-excursion
-                              (or (todos-time-string-matcher lim)
-                                  (todos-date-string-matcher lim)))))
-                   (if (looking-at (regexp-quote todos-nondiary-start))
-                       (progn
-                         (replace-match "")
-                         (search-forward todos-nondiary-end (1+ end) t)
-                         (replace-match "")
-                         (todos-set-count 'diary 1))
-                     (when end
-                       (insert todos-nondiary-start)
-                       (goto-char (1+ end))
-                       (insert todos-nondiary-end)
-                       (todos-set-count 'diary -1))))))
-             (unless (or marked all) (throw 'stop nil))
-             (todos-forward-item))))))
-    (todos-update-categories-sexp)))
+             (if (= (length todos-categories) 1)
+                 ;; If deleted category was the only one, delete the file.
+                 (progn
+                   ;; FIXME: need this?
+                   (setq todos-categories nil)
+                   (todos-reevaluate-defcustoms)
+                   (delete-file todos-current-todos-file)
+                   (kill-buffer)
+                   (message "Deleted empty Todos file %s."
+                            todos-current-todos-file))
+               ;; FIXME: what about todos-categories-full ?
+               (setq todos-categories (delete (assoc cat todos-categories)
+                                              todos-categories))
+               (todos-update-categories-sexp)
+               (setq todos-category-number
+                     (1+ (mod todos-category-number (length todos-categories))))
+               (todos-category-select)
+               (goto-char (point-min))
+               (message "Deleted category %s." cat)))))))))
 
-(defun todos-toggle-item-diary-nonmarking ()
-  "Mark or unmark this todos diary item for calendar display.
-See `diary-nonmarking-symbol'."
+(defun todos-raise-category (&optional lower)
+  "Raise priority of category point is on in Todos Categories buffer.
+With non-nil argument LOWER, lower the category's priority."
   (interactive)
-  (let ((buffer-read-only))
+  (let (num)
     (save-excursion
-      (todos-item-start)
-      (unless (looking-at (regexp-quote todos-nondiary-start))
-       (if (looking-at (regexp-quote diary-nonmarking-symbol))
-           (replace-match "")
-         (insert diary-nonmarking-symbol))))))
-
-(defun todos-toggle-diary-nonmarking ()
-  "Mark or unmark this category's todos diary items for calendar.
-See `diary-nonmarking-symbol'."
-  (interactive)
-  (save-excursion
-    (goto-char (point-min))
-    (while (not (eobp))
-      (todos-toggle-item-diary-nonmarking)
-      (todos-forward-item))))
+      (forward-line 0)
+      (skip-chars-forward " ")
+      (setq num (number-at-point)))
+    (when (and num (if lower
+                      (< num (length todos-categories))
+                    (> num 1)))
+      (let* ((col (current-column))
+            (beg (progn (forward-line (if lower 0 -1)) (point)))
+            (num1 (progn (skip-chars-forward " ") (1- (number-at-point))))
+            (num2 (1+ num1))
+            (end (progn (forward-line 2) (point)))
+            (catvec (vconcat todos-categories))
+            (cat1-list (aref catvec num1))
+            (cat2-list (aref catvec num2))
+            (cat1 (car cat1-list))
+            (cat2 (car cat2-list))
+            buffer-read-only newcats)
+       (delete-region beg end)
+       (setq num1 (1+ num1))
+       (setq num2 (1- num2))
+       (setq num num2)
+       (todos-insert-category-line cat2)
+       (setq num num1)
+       (todos-insert-category-line cat1)
+       (aset catvec num2 (cons cat2 (cdr cat2-list)))
+       (aset catvec num1 (cons cat1 (cdr cat1-list)))
+       (setq todos-categories (append catvec nil))
+       (setq newcats todos-categories)
+       (with-current-buffer (get-file-buffer todos-current-todos-file)
+         (setq todos-categories newcats)
+         (todos-update-categories-sexp))
+       (forward-line (if lower -1 -2))
+       (forward-char col)))))
 
-(defun todos-print (&optional to-file)
-  "Produce a printable version of the current Todos buffer.
-This includes overlays, indentation, and, depending on the value
-of `todos-print-function', faces.  With non-nil argument TO-FILE
-write the printable version to a file; otherwise, send it to the
-default printer."
+(defun todos-lower-category ()
+  "Lower priority of category point is on in Todos Categories buffer."
   (interactive)
-  (let ((buf todos-tmp-buffer-name)    ;FIXME
-       (header (cond
-                ((eq major-mode 'todos-mode)
-                 (concat "Todos File: "
-                         (file-name-sans-extension
-                          (file-name-nondirectory todos-current-todos-file))
-                         "\nCategory: " (todos-current-category)))
-                ((eq major-mode 'todos-filter-items-mode)
-                 "Todos Top Priorities")))
-       (prefix (propertize (concat todos-prefix " ")
-                           'face 'todos-prefix-string))
-       (num 0)
-       (fill-prefix (make-string todos-indent-to-here 32))
-       (content (buffer-string))
-       file)
-    (with-current-buffer (get-buffer-create buf)
-      (insert content)
-      (goto-char (point-min))
-      (while (not (eobp))
-       (let ((beg (point))
-             (end (save-excursion (todos-item-end))))
-         (when todos-number-prefix
-           (setq num (1+ num))
-           (setq prefix (propertize (concat (number-to-string num) " ")
-                                    'face 'todos-prefix-string)))
-         (insert prefix)
-         (fill-region beg end))
-       ;; Calling todos-forward-item infloops at todos-item-start due to
-       ;; non-overlay prefix, so search for item start instead.
-       (if (re-search-forward todos-item-start nil t)
-           (beginning-of-line)
-         (goto-char (point-max))))
-      (if (re-search-backward (concat "^" (regexp-quote todos-category-done))
-                             nil t)
-         (replace-match todos-done-separator))
-      (goto-char (point-min))
-      (insert header)
-      (newline 2)
-      (if to-file
-         (let ((file (read-file-name "Print to file: ")))
-           (funcall todos-print-function file))
-       (funcall todos-print-function)))
-    (kill-buffer buf)))
+  (todos-raise-category t))
 
-(defun todos-print-to-file ()
-  "Save printable version of this Todos buffer to a file."
+(defun todos-move-category ()
+  "Move current category to a different Todos file.
+If current category has archived items, also move those to the
+archive of the file moved to, creating it if it does not exist."
   (interactive)
-  (todos-print t))
-
-;; ---------------------------------------------------------------------------
-
-;;; Internals
-
-(defvar todos-date-pattern             ;FIXME: start with "^" ?
-  (let ((dayname (diary-name-pattern calendar-day-name-array nil t)))
-    (concat "\\(?:" dayname "\\|"
-           (let ((dayname)
-                 (monthname (format "\\(?:%s\\|\\*\\)"
-                                    (diary-name-pattern
-                                     calendar-month-name-array
-                                     calendar-month-abbrev-array t)))
-                 (month "\\(?:[0-9]+\\|\\*\\)")
-                 (day "\\(?:[0-9]+\\|\\*\\)")
-                 (year "-?\\(?:[0-9]+\\|\\*\\)"))
-             (mapconcat 'eval calendar-date-display-form ""))
-           "\\)"))
-  "Regular expression matching a Todos date header.")
-
-(defvar todos-date-string-start
-  ;; FIXME: with ? matches anything
-  (concat "^\\(" (regexp-quote todos-nondiary-start) "\\|"
-         (regexp-quote diary-nonmarking-symbol) "\\)?")
-  "Regular expression matching part of item header before the date.")
-
-(defvar todos-done-string-start
-  (concat "^\\[" (regexp-quote todos-done-string))
-  "Regular expression matching start of done item.")
-
-(defun todos-date-string-matcher (lim)
-  "Search for Todos date strings within LIM for font-locking."
-  (re-search-forward
-   (concat todos-date-string-start "\\(?1:" todos-date-pattern "\\)") lim t))
-
-(defun todos-time-string-matcher (lim)
-  "Search for Todos time strings within LIM for font-locking."
-  (re-search-forward (concat todos-date-string-start todos-date-pattern
-                            " \\(?1:" diary-time-regexp "\\)") lim t))
-
-(defun todos-done-string-matcher (lim)
-  "Search for Todos done headers within LIM for font-locking."
-  (re-search-forward (concat todos-done-string-start
-                     "[^][]+]")
-                    lim t))
-
-(defun todos-comment-string-matcher (lim)
-  "Search for Todos done comment within LIM for font-locking."
-  (re-search-forward (concat "\\[\\(?1:" todos-comment-string "\\):")
-                    lim t))
-
-(defun todos-category-string-matcher (lim)
-  "Search for Todos category headers within LIM for font-locking."
-  (if (eq major-mode 'todos-filter-items-mode)
-      (re-search-forward
-       ;; (concat "^\\(?1:" (regexp-quote todos-category-beg) ".*\\)$")
-       (concat "\\(?:^\\[?" todos-date-pattern "\\(?: " diary-time-regexp
-              "\\)?\\]?\\) \\(?1:\\[.+\\]\\)") lim t)))
+  (when (or (> (length todos-categories) 1)
+           (y-or-n-p (concat "This is the only category in this file; "
+                             "moving it will also delete the file.\n"
+                             "Do you want to proceed? ")))
+    (let* ((ofile todos-current-todos-file)
+          (cat (todos-current-category))
+          (nfile (todos-read-file-name "Choose a Todos file: " nil t))
+          (archive (concat (file-name-sans-extension ofile) ".toda"))
+          (buffers (append (list ofile)
+                           (unless (zerop (todos-get-count 'archived cat))
+                             (list archive))))
+          new)
+      (dolist (buf buffers)
+       (with-current-buffer (find-file-noselect buf)
+         (widen)
+         (goto-char (point-max))
+         (let* ((beg (re-search-backward
+                      (concat "^"
+                              (regexp-quote (concat todos-category-beg cat)))
+                      nil t))
+                (end (if (re-search-forward
+                          (concat "^" (regexp-quote todos-category-beg))
+                          nil t 2)
+                         (match-beginning 0)
+                       (point-max)))
+                (content (buffer-substring-no-properties beg end))
+                (counts (cdr (assoc cat todos-categories)))
+                buffer-read-only)
+           ;; Move the category to the new file.  Also update or create
+           ;; archive file if necessary.
+           (with-current-buffer
+               (find-file-noselect
+                ;; Regenerate todos-archives in case there
+                ;; is a newly created archive.
+                (if (member buf (funcall todos-files-function t))
+                    (concat (file-name-sans-extension nfile) ".toda")
+                  nfile))
+             (let* ((nfile-short (todos-short-file-name nfile))
+                    (prompt (concat
+                             (format "Todos file \"%s\" already has "
+                                     nfile-short)
+                             (format "the category \"%s\";\n" cat)
+                             "enter a new category name: "))
+                    buffer-read-only)
+               (widen)
+               (goto-char (point-max))
+               (insert content)
+               ;; If the file moved to has a category with the same
+               ;; name, rename the moved category.
+               (when (assoc cat todos-categories)
+                 (unless (member (file-truename (buffer-file-name))
+                                 (funcall todos-files-function t))
+                   (setq new (read-from-minibuffer prompt))
+                   (setq new (todos-validate-name new 'category))))
+               ;; Replace old with new name in Todos and archive files.
+               (when new
+                 (goto-char (point-max))
+                 (re-search-backward
+                  (concat "^" (regexp-quote todos-category-beg)
+                          "\\(" (regexp-quote cat) "\\)") nil t)
+                 (replace-match new nil nil nil 1)))
+             (setq todos-categories
+                   (append todos-categories (list (cons new counts))))
+             (todos-update-categories-sexp)
+             ;; If archive was just created, save it to avoid "File <xyz> no
+             ;; longer exists!" message on invoking
+             ;; `todos-view-archived-items'.  FIXME: maybe better to save
+             ;; unconditionally?
+             (unless (file-exists-p (buffer-file-name))
+               (save-buffer))
+             (todos-category-number (or new cat))
+             (todos-category-select))
+           ;; Delete the category from the old file, and if that was the
+           ;; last category, delete the file.  Also handle archive file
+           ;; if necessary.
+           (remove-overlays beg end)
+           (delete-region beg end)
+           (goto-char (point-min))
+           ;; Put point after todos-categories sexp.
+           (forward-line)
+           (if (eobp)          ; Aside from sexp, file is empty.
+               (progn
+                 ;; Skip confirming killing the archive buffer.
+                 (set-buffer-modified-p nil)
+                 (delete-file todos-current-todos-file)
+                 (kill-buffer)
+                 (when (member todos-current-todos-file todos-files)
+                   (todos-reevaluate-defcustoms)))
+             (setq todos-categories (delete (assoc cat todos-categories)
+                                            todos-categories))
+             (todos-update-categories-sexp)
+             (todos-category-select)))))
+      (set-window-buffer (selected-window)
+                        (set-buffer (find-file-noselect nfile)))
+      (todos-category-number (or new cat))
+      (todos-category-select))))
 
-(defun todos-check-format ()
-  "Signal an error if the current Todos file is ill-formatted."
-  (save-excursion
-    (save-restriction
-      (widen)
+(defun todos-merge-category ()
+  "Merge current category into another category in this file.
+The current category's todo and done items are appended to the
+chosen category's todo and done items, respectively, which
+becomes the current category, and the category moved from is
+deleted."
+  (interactive)
+  (let ((buffer-read-only nil)
+       (cat (todos-current-category))
+       (goal (todos-read-category "Category to merge to: " t)))
+    (widen)
+    ;; FIXME: check if cat has archived items and merge those too
+    (let* ((cbeg (progn
+                  (re-search-backward
+                   (concat "^" (regexp-quote todos-category-beg)) nil t)
+                  (point)))
+          (tbeg (progn (forward-line) (point)))
+          (dbeg (progn
+                  (re-search-forward
+                   (concat "^" (regexp-quote todos-category-done)) nil t)
+                  (forward-line) (point)))
+          (tend (progn (forward-line -2) (point)))
+          (cend (progn
+                  (if (re-search-forward
+                       (concat "^" (regexp-quote todos-category-beg)) nil t)
+                      (match-beginning 0)
+                    (point-max))))
+          (todo (buffer-substring-no-properties tbeg tend))
+          (done (buffer-substring-no-properties dbeg cend))
+          here)
       (goto-char (point-min))
-      (let ((legit (concat "^\\(" (regexp-quote todos-category-beg) "\\)"
-                          "\\|\\(\\[?" todos-date-pattern "\\)"
-                          "\\|\\([ \t]+[^ \t]*\\)"
-                          "\\|$")))
-       (while (not (eobp))
-         (unless (looking-at legit)
-           (error "Illegitimate Todos file format at line %d"
-                  (line-number-at-pos (point))))
-         (forward-line)))))
-  (message "This Todos file is well-formatted."))
-
-(defun todos-after-find-file ()
-  "Show Todos files correctly when visited from outside of Todos mode."
-  (and (member this-command todos-visit-files-commands)
-       (= (- (point-max) (point-min)) (buffer-size))
-       (member major-mode '(todos-mode todos-archive-mode))
-       (todos-category-select)))
-
-(defun todos-wrap-and-indent ()
-  "Use word wrapping on long lines and indent with a wrap prefix.
-The amount of indentation is given by user option
-`todos-indent-to-here'."
-  (set (make-local-variable 'word-wrap) t)
-  (set (make-local-variable 'wrap-prefix) (make-string todos-indent-to-here 32))
-  (unless (member '(continuation) fringe-indicator-alist)
-    (push '(continuation) fringe-indicator-alist)))
-
-(defun todos-indent ()
-  "Indent from point to `todos-indent-to-here'."
-  (indent-to todos-indent-to-here todos-indent-to-here))
-
-(defun todos-prefix-overlays ()
-  "Put before-string overlay in front of this category's items.
-The overlay's value is the string `todos-prefix' or with non-nil
-`todos-number-prefix' an integer in the sequence from 1 to the
-number of todo or done items in the category indicating the
-item's priority.  Todo and done items are numbered independently
-of each other."
-  (when (or todos-number-prefix
-           (not (string-match "^[[:space:]]*$" todos-prefix)))
-    (let ((prefix (propertize (concat todos-prefix " ")
-                             'face 'todos-prefix-string))
-         (num 0))
-      (save-excursion
-       (goto-char (point-min))
-       (while (not (eobp))
-         (when (or (todos-date-string-matcher (line-end-position))
-                   (todos-done-string-matcher (line-end-position)))
-           (goto-char (match-beginning 0))
-           (when todos-number-prefix
-             (setq num (1+ num))
-             ;; Reset number for done items.
-             (when
-                 ;; FIXME: really need this?
-                 ;; If last not done item is multiline, then
-                 ;; todos-done-string-matcher skips empty line, so have
-                 ;; to look back.
-                 (and (looking-at todos-done-string-start)
-                      (looking-back (concat "^"
-                                            (regexp-quote todos-category-done)
-                                            "\n")))
-               (setq num 1))
-             (setq prefix (propertize (concat (number-to-string num) " ")
-                                      'face 'todos-prefix-string)))
-           (let ((ovs (overlays-in (point) (point)))
-                 marked ov-pref)
-             (if ovs
-                 (dolist (ov ovs)
-                   (let ((val (overlay-get ov 'before-string)))
-                     (if (equal val "*")
-                         (setq marked t)
-                       (setq ov-pref val)))))
-             (unless (equal ov-pref prefix)
-               (remove-overlays (point) (point)) ; 'before-string) doesn't work
-               (overlay-put (make-overlay (point) (point))
-                            'before-string prefix)
-               (and marked (overlay-put (make-overlay (point) (point))
-                                        'before-string todos-item-mark)))))
-         (forward-line))))))
+      (re-search-forward
+       (concat "^" (regexp-quote (concat todos-category-beg goal))) nil t)
+      (re-search-forward
+       (concat "^" (regexp-quote todos-category-done)) nil t)
+      (forward-line -1)
+      (setq here (point))
+      (insert todo)
+      (goto-char (if (re-search-forward
+                     (concat "^" (regexp-quote todos-category-beg)) nil t)
+                    (match-beginning 0)
+                  (point-max)))
+      (insert done)
+      (remove-overlays cbeg cend)
+      (delete-region cbeg cend)
+      (todos-set-count 'todo (todos-get-count 'todo cat) goal)
+      (todos-set-count 'done (todos-get-count 'done cat) goal)
+      (setq todos-categories (delete (assoc cat todos-categories)
+                                    todos-categories))
+      (todos-update-categories-sexp)
+      (todos-category-number goal)
+      (todos-category-select)
+      ;; Put point at the start of the merged todo items.
+      ;; FIXME: what if there are no merged todo items but only done items?
+      (goto-char here))))
+      
+;; FIXME
+(defun todos-merge-categories ()
+  ""
+  (interactive)
+  (let* ((cats (mapcar 'car todos-categories))
+        (goal (todos-read-category "Category to merge to: " t))
+        (prompt (format "Merge to %s (type C-g to finish)? " goal))
+        (source (let ((inhibit-quit t) l)
+                 (while (not (eq last-input-event 7))
+                   (dolist (c cats)
+                     (when (y-or-n-p prompt)
+                       (push c l)
+                       (setq cats (delete c cats))))))))
+    (widen)
+  ))
 
-(defun todos-reset-prefix (symbol value)
-  "The :set function for `todos-prefix' and `todos-number-prefix'."
-  (let ((oldvalue (symbol-value symbol))
-       (files (append todos-files todos-archives)))
-    (custom-set-default symbol value)
-    (when (not (equal value oldvalue))
-      (dolist (f files)
-       (with-current-buffer (find-file-noselect f)
-         (save-window-excursion
-           (todos-show)
-           (save-excursion
-             (widen)
-             (goto-char (point-min))
-             (while (not (eobp))
-               (remove-overlays (point) (point)); 'before-string prefix)
-               (forward-line)))
-           ;; Activate the new setting (save-restriction does not help).
-           (save-excursion (todos-category-select))))))))
+;; FIXME: make insertion options customizable per category?
+;;;###autoload
+(defun todos-insert-item (&optional arg diary nonmarking date-type time
+                                   region-or-here)
+  "Add a new Todo item to a category.
+\(See the note at the end of this document string about key
+bindings and convenience commands derived from this command.)
 
-(defun todos-reset-nondiary-marker (symbol value)
-  "The :set function for user option `todos-nondiary-marker'."
-  (let ((oldvalue (symbol-value symbol))
-       (files (append todos-files todos-archives)))
-    (custom-set-default symbol value)
-    ;; Need to reset these to get font-locking right.
-    (setq todos-nondiary-start (nth 0 todos-nondiary-marker)
-         todos-nondiary-end (nth 1 todos-nondiary-marker)
-         todos-date-string-start
-         ;; FIXME: with ? matches anything
-         (concat "^\\(" (regexp-quote todos-nondiary-start) "\\|"
-                 (regexp-quote diary-nonmarking-symbol) "\\)?"))
-    (when (not (equal value oldvalue))
-      (dolist (f files)
-       (with-current-buffer (find-file-noselect f)
-         (let (buffer-read-only)
-           (widen)
-           (goto-char (point-min))
-           (while (not (eobp))
-             (if (re-search-forward
-                  (concat "^\\(" todos-done-string-start "[^][]+] \\)?"
-                          "\\(?1:" (regexp-quote (car oldvalue))
-                          "\\)" todos-date-pattern "\\( "
-                          diary-time-regexp "\\)?\\(?2:"
-                          (regexp-quote (cadr oldvalue)) "\\)")
-                  nil t)
-                 (progn
-                   (replace-match (nth 0 value) t t nil 1)
-                   (replace-match (nth 1 value) t t nil 2))
-               (forward-line)))
-           (todos-category-select)))))))
+With no (or nil) prefix argument ARG, add the item to the current
+category; with one prefix argument (C-u), prompt for a category
+from the current Todos file; with two prefix arguments (C-u C-u),
+first prompt for a Todos file, then a category in that file.  If
+a non-existing category is entered, ask whether to add it to the
+Todos file; if answered affirmatively, add the category and
+insert the item there.
 
-(defun todos-reset-done-string (symbol value)
-  "The :set function for user option `todos-done-string'."
-  (let ((oldvalue (symbol-value symbol))
-       (files (append todos-files todos-archives)))
-    (custom-set-default symbol value)
-    ;; Need to reset this to get font-locking right.
-    (setq todos-done-string-start
-         (concat "^\\[" (regexp-quote todos-done-string)))
-    (when (not (equal value oldvalue))
-      (dolist (f files)
-       (with-current-buffer (find-file-noselect f)
-         (let (buffer-read-only)
-           (widen)
-           (goto-char (point-min))
-           (while (not (eobp))
-             (if (re-search-forward
-                  (concat "^" (regexp-quote todos-nondiary-start)
-                          "\\(" (regexp-quote oldvalue) "\\)")
-                  nil t)
-                 (replace-match value t t nil 1)
-               (forward-line)))
-           (todos-category-select)))))))
+When argument DIARY is non-nil, this overrides the intent of the
+user option `todos-include-in-diary' for this item: if
+`todos-include-in-diary' is nil, include the item in the Fancy
+Diary display, and if it is non-nil, exclude the item from the
+Fancy Diary display.  When DIARY is nil, `todos-include-in-diary'
+has its intended effect.
 
-(defun todos-reset-comment-string (symbol value)
-  "The :set function for user option `todos-comment-string'."
-  (let ((oldvalue (symbol-value symbol))
-       (files (append todos-files todos-archives)))
-    (custom-set-default symbol value)
-    (when (not (equal value oldvalue))
-      (dolist (f files)
-       (with-current-buffer (find-file-noselect f)
-         (let (buffer-read-only)
-           (save-excursion
-             (widen)
-             (goto-char (point-min))
-             (while (not (eobp))
-               (if (re-search-forward
-                    (concat
-                            "\\[\\(" (regexp-quote oldvalue) "\\): [^]]*\\]")
-                    nil t)
-                   (replace-match value t t nil 1)
-                 (forward-line)))
-             (todos-category-select))))))))
+When the item is included in the Fancy Diary display and the
+argument NONMARKING is non-nil, this overrides the intent of the
+user option `todos-diary-nonmarking' for this item: if
+`todos-diary-nonmarking' is nil, append `diary-nonmarking-symbol'
+to the item, and if it is non-nil, omit `diary-nonmarking-symbol'.
 
-(defun todos-reset-categories (symbol value)
-  "The :set function for `todos-ignore-archived-categories'."
-  (custom-set-default symbol value)
-  (dolist (f (funcall todos-files-function))
-    (with-current-buffer (find-file-noselect f)
-      (if value
-         (setq todos-categories-full todos-categories
-               todos-categories (todos-truncate-categories-list))
-       (setq todos-categories todos-categories-full
-             todos-categories-full nil))
-      (todos-category-select))))
+The argument DATE-TYPE determines the content of the item's
+mandatory date header string and how it is added:
+- If DATE-TYPE is the symbol `calendar', the Calendar pops up and
+  when the user puts the cursor on a date and hits RET, that
+  date, in the format set by `calendar-date-display-form',
+  becomes the date in the header.
+- If DATE-TYPE is the symbol `date', the header contains the date
+  in the format set by `calendar-date-display-form', with year,
+  month and day individually prompted for (month with tab
+  completion).
+- If DATE-TYPE is the symbol `dayname' the header contains a
+  weekday name instead of a date, prompted for with tab
+  completion.
+- If DATE-TYPE has any other value (including nil or none) the
+  header contains the current date (in the format set by
+  `calendar-date-display-form').
 
-(defun todos-toggle-show-current-file (symbol value)
-  "The :set function for user option `todos-show-current-file'."
-  (custom-set-default symbol value)
-  (if value
-      (add-hook 'pre-command-hook 'todos-show-current-file nil t)
-    (remove-hook 'pre-command-hook 'todos-show-current-file t)))
+With non-nil argument TIME prompt for a time string, which must
+match `diary-time-regexp'.  Typing `<return>' at the prompt
+returns the current time, if the user option
+`todos-always-add-time-string' is non-nil, otherwise the empty
+string (i.e., no time string).  If TIME is absent or nil, add or
+omit the current time string according as
+`todos-always-add-time-string' is non-nil or nil, respectively.
 
-(defun todos-show-current-file ()
-  "Visit current instead of default Todos file with `todos-show'.
-This function is added to `pre-command-hook' when user option
-`todos-show-current-file' is set to non-nil."
-  (setq todos-global-current-todos-file todos-current-todos-file))
-  ;; (and (eq major-mode 'todos-mode)
-       ;; (setq todos-global-current-todos-file (buffer-file-name))))
+The argument REGION-OR-HERE determines the source and location of
+the new item:
+- If the REGION-OR-HERE is the symbol `here', prompt for the text
+  of the new item and insert it directly above the todo item at
+  point (hence lowering the priority of the remaining items), or
+  if point is on the empty line below the last todo item, insert
+  the new item there.  An error is signalled if
+  `todos-insert-item' is invoked with `here' outside of the
+  current category.
+- If REGION-OR-HERE is the symbol `region', use the region of the
+  current buffer as the text of the new item, depending on the
+  value of user option `todos-use-only-highlighted-region': if
+  this is non-nil, then use the region only when it is
+  highlighted; otherwise, use the region regardless of
+  highlighting.  An error is signalled if there is no region in
+  the current buffer.  Prompt for the item's priority in the
+  category (an integer between 1 and one more than the number of
+  items in the category), and insert the item accordingly.
+- If REGION-OR-HERE has any other value (in particular, nil or
+  none), prompt for the text and the item's priority, and insert
+  the item accordingly.
 
-;; FIXME: rename to todos-set-category-number ?
-(defun todos-category-number (cat)
-  "Set and return buffer-local value of `todos-category-number'.
-This value is one more than the index of category CAT, starting
-with one instead of zero, so that the highest priority
-category (see `todos-display-categories') has the number one."
-  (let ((categories (mapcar 'car todos-categories)))
-    (setq todos-category-number
-         (1+ (- (length categories)
-                (length (member cat categories)))))))
+To facilitate using these arguments when inserting a new todo
+item, convenience commands have been defined for all admissible
+combinations (96 in all!) together with mnenomic key bindings
+based on on the name of the arguments and their order in the
+command's argument list: diar_y_ - nonmar_k_ing - _c_alendar or
+_d_ate or day_n_ame - _t_ime - _r_egion or _h_ere.  These key
+combinations are appended to the basic insertion key (i) and keys
+that allow a following key must be doubled when used finally.
+For example, `iyh' will insert a new item with today's date,
+marked according to the DIARY argument described above, and with
+priority according to the HERE argument; while `iyy' does the
+same except the priority is not given by HERE but by prompting."
+;;   An alternative interface for customizing key
+;; binding is also provided with the function
+;; `todos-insertion-bindings'."                ;FIXME
+  (interactive "P")
+  (let ((region (eq region-or-here 'region))
+       (here (eq region-or-here 'here)))
+    (when region
+      ;; FIXME: better to use use-region-p or region-active-p?
+      (unless (and (if todos-use-only-highlighted-region
+                      transient-mark-mode
+                    t)
+                  mark-active)
+       (error "The mark is not set now, so there is no region")))
+    (let* ((buf (current-buffer))
+          (new-item (if region
+                        ;; FIXME: or keep properties?
+                        (buffer-substring-no-properties
+                         (region-beginning) (region-end))
+                      (read-from-minibuffer "Todo item: ")))
+          (date-string (cond
+                        ((eq date-type 'date)
+                         (todos-read-date))
+                        ((eq date-type 'dayname)
+                         (todos-read-dayname))
+                        ((eq date-type 'calendar)
+                         (setq todos-date-from-calendar t)
+                         (todos-set-date-from-calendar))
+                        (t (calendar-date-string (calendar-current-date) t t))))
+          (time-string (or (and time (todos-read-time))
+                           (and todos-always-add-time-string
+                                (substring (current-time-string) 11 16)))))
+      (setq todos-date-from-calendar nil)
+      (cond ((equal arg '(16))         ; FIXME: cf. set-mark-command
+            (todos-jump-to-category nil t)
+            (set-window-buffer
+             (selected-window)
+             (set-buffer (get-file-buffer todos-global-current-todos-file))))
+           ((equal arg '(4))           ; FIXME: just arg?
+            (todos-jump-to-category)
+            (set-window-buffer
+             (selected-window)
+             (set-buffer (get-file-buffer todos-global-current-todos-file))))
+           (t
+            (when (not (derived-mode-p 'todos-mode)) (todos-show))))
+      (let (buffer-read-only)
+       (setq new-item
+             ;; Add date, time and diary marking as required.
+             (concat (if (not (and diary (not todos-include-in-diary)))
+                         todos-nondiary-start
+                       (when (and nonmarking (not todos-diary-nonmarking))
+                         diary-nonmarking-symbol))
+                     date-string (unless (and time-string
+                                              (string= time-string ""))
+                                   (concat " " time-string))
+                     (when (not (and diary (not todos-include-in-diary)))
+                       todos-nondiary-end)
+                     " " new-item))
+       ;; Indent newlines inserted by C-q C-j if nonspace char follows.
+       (setq new-item (replace-regexp-in-string
+                       "\\(\n\\)[^[:blank:]]"
+                       (concat "\n" (make-string todos-indent-to-here 32))
+                       new-item nil nil 1))
+       (if here
+           (cond ((not (eq major-mode 'todos-mode))
+                  (error "Cannot insert a todo item here outside of Todos mode"))
+                 ((not (eq buf (current-buffer)))
+                  (error "Cannot insert an item here after changing buffer"))
+                 ((or (todos-done-item-p)
+                      ;; Point on last blank line.
+                      (save-excursion (forward-line -1) (todos-done-item-p)))
+                  (error "Cannot insert a new item in the done item section"))
+                 (t
+                  (todos-insert-with-overlays new-item)))
+         (todos-set-item-priority new-item (todos-current-category) t))
+       (todos-set-count 'todo 1)
+       (if (or diary todos-include-in-diary) (todos-set-count 'diary 1))
+       (todos-update-categories-sexp)))))
 
-(defun todos-current-category ()
-  "Return the name of the current category."
-  (car (nth (1- todos-category-number) todos-categories)))
+(defvar todos-date-from-calendar nil
+  "Helper variable for setting item date from the Emacs Calendar.")
 
-(defun todos-category-select ()
-  "Display the current category correctly.
+(defun todos-set-date-from-calendar ()
+  "Return string of date chosen from Calendar."
+  (when todos-date-from-calendar
+    (let (calendar-view-diary-initially-flag)
+      (calendar))
+    ;; *Calendar* is now current buffer.
+    (local-set-key (kbd "RET") 'exit-recursive-edit)
+    (message "Put cursor on a date and type <return> to set it.")
+    ;; FIXME: is there a better way than recursive-edit?
+    ;; FIXME: use unwind-protect?  Check recursive-depth?
+    (recursive-edit)
+    (setq todos-date-from-calendar
+         (calendar-date-string (calendar-cursor-to-date t) t t))
+    (calendar-exit)
+    todos-date-from-calendar))
 
-With non-nil user option `todos-show-done-only' display only the
-category's done (but not archived) items; else (the default)
-display just the todo items, or with non-nil user option
-`todos-show-with-done' also display the category's done items
-below the todo items."
-  (let ((name (todos-current-category))
-       cat-begin cat-end done-start done-sep-start done-end)
-    (widen)
-    (goto-char (point-min))
-    (re-search-forward
-     (concat "^" (regexp-quote (concat todos-category-beg name)) "$") nil t)
-    (setq cat-begin (1+ (line-end-position)))
-    (setq cat-end (if (re-search-forward
-                      (concat "^" (regexp-quote todos-category-beg)) nil t)
-                     (match-beginning 0)
-                   (point-max)))
-    (setq mode-line-buffer-identification
-         (funcall todos-mode-line-function name))
-    (narrow-to-region cat-begin cat-end)
-    (todos-prefix-overlays)
-    (goto-char (point-min))
-    (if (re-search-forward (concat "\n\\(" (regexp-quote todos-category-done)
-                                  "\\)") nil t)
-       (progn
-         (setq done-start (match-beginning 0))
-         (setq done-sep-start (match-beginning 1))
-         (setq done-end (match-end 0)))
-      (error "Category %s is missing todos-category-done string" name))
-    (if todos-show-done-only
-       (narrow-to-region (1+ done-end) (point-max))
-      ;; Display or hide done items as per todos-show-with-done.
-      ;; FIXME: use todos-done-string-start ?
-      (when (re-search-forward (concat "\n\\(\\["
-                                      (regexp-quote todos-done-string)
-                                      "\\)") nil t)
-       (let (done-sep prefix ov-pref ov-done)
-         ;; FIXME: delete overlay when not viewing done items?
-         (when todos-show-with-done
-           (setq done-sep todos-done-separator)
-           (setq done-start cat-end)
-           (setq ov-pref (make-overlay done-sep-start done-end))
-           (overlay-put ov-pref 'display done-sep))))
-      (narrow-to-region (point-min) done-start))))
+;; FIXME: autoload when key-binding is defined in calendar.el
+(defun todos-insert-item-from-calendar ()
+  ""
+  (interactive)
+  ;; FIXME: todos-current-todos-file is nil here, better to solicit Todos file?
+  ;; FIXME: t-g-c-t-f is nil if no Todos file has been visited 
+  (pop-to-buffer (file-name-nondirectory todos-global-current-todos-file))
+  (todos-show)
+  ;; FIXME: this now calls todos-set-date-from-calendar
+  (todos-insert-item t 'calendar))
 
-(defun todos-insert-with-overlays (item)
-  "Insert ITEM and update prefix/priority number overlays."
-  (todos-item-start)
-  (insert item "\n")
-  (todos-backward-item)
-  (todos-prefix-overlays))
+;; FIXME: calendar is loaded before todos
+;; (add-hook 'calendar-load-hook
+         ;; (lambda ()
+           (define-key calendar-mode-map "it" 'todos-insert-item-from-calendar);))
 
-(defvar todos-item-start ;; (concat "^\\(\\[\\(" (regexp-quote todos-done-string)
-                        ;;      "\\)?\\)?" todos-date-pattern)
-  (concat "\\(" todos-date-string-start "\\|" todos-done-string-start
-         "\\)" todos-date-pattern)
-  "String identifying start of a Todos item.")
+(defun todos-delete-item ()
+  "Delete at least one item in this category.
 
-(defun todos-item-start ()
-  "Move to start of current Todos item and return its position."
-  (unless (or
-          ;; Point is either on last item in this category or on the empty
-          ;; line between done and not done items.
-          (looking-at "^$")
-          ;; There are no done items in this category yet.
-          (looking-at (regexp-quote todos-category-beg)))
-    (goto-char (line-beginning-position))
-    (while (not (looking-at todos-item-start))
-      (forward-line -1))
-    (point)))
+If there are marked items, delete all of these; otherwise, delete
+the item at point."
+  (interactive)
+  (let* ((cat (todos-current-category))
+        (marked (assoc cat todos-categories-with-marks))
+        (item (unless marked (todos-item-string)))
+        (ov (make-overlay (save-excursion (todos-item-start))
+                          (save-excursion (todos-item-end))))
+        ;; FIXME: make confirmation an option
+        (answer (if marked
+                    (y-or-n-p "Permanently delete all marked items? ")
+                  (when item
+                    (overlay-put ov 'face 'todos-search)
+                    (y-or-n-p (concat "Permanently delete this item? ")))))
+        (opoint (point))
+        buffer-read-only)
+    (when answer
+      (and marked (goto-char (point-min)))
+      (catch 'done
+       (while (not (eobp))
+         (if (or (and marked (todos-marked-item-p)) item)
+             (progn
+               (if (todos-done-item-p)
+                   (todos-set-count 'done -1)
+                 (todos-set-count 'todo -1 cat)
+                 (and (todos-diary-item-p) (todos-set-count 'diary -1)))
+               (delete-overlay ov)
+               (todos-remove-item)
+               ;; Don't leave point below last item.
+               (and item (bolp) (eolp) (< (point-min) (point-max))
+                    (todos-backward-item))
+               (when item 
+                 (throw 'done (setq item nil))))
+           (todos-forward-item))))
+      (when marked
+       (remove-overlays (point-min) (point-max) 'before-string todos-item-mark)
+       (setq todos-categories-with-marks
+             (assq-delete-all cat todos-categories-with-marks))
+       (goto-char opoint))
+      (todos-update-categories-sexp)
+      (todos-prefix-overlays))
+    (if ov (delete-overlay ov))))
+
+(defun todos-edit-item ()
+  "Edit the Todo item at point.
+If the item consists of only one logical line, edit it in the
+minibuffer; otherwise, edit it in Todos Edit mode."
+  (interactive)
+  (when (todos-item-string)
+    (let* ((buffer-read-only)
+          (start (todos-item-start))
+          (item-beg (progn
+                      (re-search-forward
+                       (concat todos-date-string-start todos-date-pattern
+                               "\\( " diary-time-regexp "\\)?"
+                               (regexp-quote todos-nondiary-end) "?")
+                       (line-end-position) t)
+                      (1+ (- (point) start))))
+          (item (todos-item-string))
+          (multiline (> (length (split-string item "\n")) 1))
+          (opoint (point)))
+      (if multiline
+         (todos-edit-multiline t)
+       (let ((new (read-string "Edit: " (cons item item-beg))))
+         (while (not (string-match
+                      (concat todos-date-string-start todos-date-pattern) new))
+           (setq new (read-from-minibuffer
+                      "Item must start with a date: " new)))
+         ;; Indent newlines inserted by C-q C-j if nonspace char follows.
+         (setq new (replace-regexp-in-string
+                    "\\(\n\\)[^[:blank:]]"
+                    (concat "\n" (make-string todos-indent-to-here 32)) new
+                    nil nil 1))
+         ;; If user moved point during editing, make sure it moves back.
+         (goto-char opoint)
+         (todos-remove-item)
+         (todos-insert-with-overlays new)
+         (move-to-column item-beg))))))
 
-(defun todos-item-end ()
-  "Move to end of current Todos item and return its position."
-  ;; Items cannot end with a blank line.
-  (unless (looking-at "^$")
-    (let ((done (todos-done-item-p)))
-      (todos-forward-item)
-      ;; Adjust if item is last unfinished one before displayed done items.
-      (when (and (not done) (todos-done-item-p))
-       (forward-line -1))
-      (backward-char))
-    (point)))
+(defun todos-edit-multiline-item ()
+  "Edit current Todo item in Todos Edit mode.
+Use of newlines invokes `todos-indent' to insure compliance with
+the format of Diary entries."
+  (interactive)
+  (todos-edit-multiline t))
 
-(defun todos-remove-item ()
-  "Internal function called in editing, deleting or moving items."
-  (let* ((beg (todos-item-start))
-        (end (progn (todos-item-end) (1+ (point))))
-        (ovs (overlays-in beg beg)))
-    ;; There can be both prefix/number and mark overlays.
-    (while ovs (delete-overlay (car ovs)) (pop ovs))
-    (delete-region beg end)))
+(defun todos-edit-multiline (&optional item)
+  ""
+  (interactive)
+  ;; FIXME: should there be only one live Todos Edit buffer?
+  ;; (let ((buffer-name todos-edit-buffer))
+  (let ((buffer-name (generate-new-buffer-name todos-edit-buffer)))
+    (set-window-buffer
+     (selected-window)
+     (set-buffer (make-indirect-buffer
+                 (file-name-nondirectory todos-current-todos-file)
+                 buffer-name)))
+    (if item
+       (narrow-to-region (todos-item-start) (todos-item-end))
+      (widen))
+    (todos-edit-mode)
+    ;; (message (concat "Type %s to check file format validity and "
+    ;;                      "return to Todos mode.\n")
+    ;;              (key-description (car (where-is-internal 'todos-edit-quit))))
+    (message "%s" (substitute-command-keys
+                  (concat "Type \\[todos-edit-quit] to check file format "
+                          "validity and return to Todos mode.\n")))))
 
-(defun todos-item-string ()
-  "Return bare text of current item as a string."
-  (let ((opoint (point))
-       (start (todos-item-start))
-       (end (todos-item-end)))
-    (goto-char opoint)
-    (and start end (buffer-substring-no-properties start end))))
+(defun todos-edit-quit ()
+  "Return from Todos Edit mode to Todos mode.
 
-(defun todos-diary-item-p ()
-  "Return non-nil if item at point is marked for diary inclusion."
-  (save-excursion
-    (todos-item-start)
-    (looking-at todos-date-pattern)))
+If the whole file was in Todos Edit mode, check before returning
+whether the file is still a valid Todos file and if so, also
+recalculate the Todos categories sexp, in case changes were made
+in the number or names of categories."
+  (interactive)
+  ;; FIXME: worth doing this only if file was actually changed?
+  (when (eq (buffer-size) (- (point-max) (point-min)))
+    (when (todos-check-format)
+      (todos-make-categories-list t)))
+  (kill-buffer)
+  ;; In case next buffer is not the one holding todos-current-todos-file.
+  (todos-show))
 
-(defun todos-done-item-p ()
-  "Return non-nil if item at point is a done item."
-  (save-excursion
-    (todos-item-start)
-    (looking-at todos-done-string-start)))
+(defun todos-edit-item-header (&optional what)
+  "Edit date/time header of at least one item.
 
-(defvar todos-item-mark (propertize (if (equal todos-prefix "*") "@" "*")
-                                   'face 'todos-mark)
-  "String used to mark items.")
+Interactively, ask whether to edit year, month and day or day of
+the week, as well as time.  If there are marked items, apply the
+changes to all of these; otherwise, edit just the item at point.  
 
-(defun todos-item-marked-p ()
-  "If this item is marked, return mark overlay."
-  (let ((ovs (overlays-in (line-beginning-position) (line-beginning-position)))
-       (mark todos-item-mark)
-       ov marked)
-    (catch 'stop
-      (while ovs
-       (setq ov (pop ovs))
-       (and (equal (overlay-get ov 'before-string) mark)
-            (throw 'stop (setq marked t)))))
-    (when marked ov)))
+Non-interactively, argument WHAT specifies whether to set the
+date from the Calendar or to today, or whether to edit only the
+date or day, or only the time."
+  (interactive)
+  (let* ((cat (todos-current-category))
+        (marked (assoc cat todos-categories-with-marks))
+        (first t)                      ; Match only first of marked items.
+        (todos-date-from-calendar t)
+        ndate ntime nheader)
+    (save-excursion
+      (or (and marked (goto-char (point-min))) (todos-item-start))
+      (catch 'stop
+       (while (not (eobp))
+         (and marked
+              (while (not (todos-marked-item-p))
+                (todos-forward-item)
+                (and (eobp) (throw 'stop nil))))
+         (re-search-forward (concat todos-date-string-start "\\(?1:"
+                                    todos-date-pattern
+                                    "\\)\\(?2: " diary-time-regexp "\\)?")
+                            (line-end-position) t)
+         (let* ((odate (match-string-no-properties 1))
+                (otime (match-string-no-properties 2))
+                (buffer-read-only))
+           (cond ((eq what 'today)
+                  (progn
+                    (setq ndate (calendar-date-string
+                                 (calendar-current-date) t t))
+                    (replace-match ndate nil nil nil 1)))
+                 ((eq what 'calendar)
+                  (setq ndate (save-match-data (todos-set-date-from-calendar)))
+                  (replace-match ndate nil nil nil 1))
+                 (t
+                  (unless (eq what 'timeonly)
+                    (when first
+                      (setq ndate (if (save-match-data
+                                        (string-match "[0-9]+" odate))
+                                      (if (y-or-n-p "Change date? ")
+                                          (todos-read-date)
+                                        (todos-read-dayname))
+                                    (if (y-or-n-p "Change day? ")
+                                        (todos-read-dayname)
+                                      (todos-read-date)))))
+                    (replace-match ndate nil nil nil 1))
+                  (unless (eq what 'dateonly)
+                    (when first
+                      (setq ntime (save-match-data (todos-read-time)))
+                      (when (< 0 (length ntime))
+                        (setq ntime (concat " " ntime))))
+                    (if otime
+                        (replace-match ntime nil nil nil 2)
+                      (goto-char (match-end 1))
+                      (insert ntime)))))
+           (setq todos-date-from-calendar nil)
+           (setq first nil))
+         (if marked
+             (todos-forward-item)
+           (goto-char (point-max))))))))
 
-(defvar todos-categories-with-marks nil
-  "Alist of categories and number of marked items they contain.")
+(defun todos-edit-item-date ()
+  "Prompt for and apply changes to current item's date."
+  (interactive)
+  (todos-edit-item-header 'dateonly))
 
-(defun todos-get-count (type &optional category)
-  "Return count of TYPE items in CATEGORY.
-If CATEGORY is nil, default to the current category."
-  (let* ((cat (or category (todos-current-category)))
-        (counts (cdr (assoc cat todos-categories)))
-        (idx (cond ((eq type 'todo) 0)
-                   ((eq type 'diary) 1)
-                   ((eq type 'done) 2)
-                   ((eq type 'archived) 3))))
-    (aref counts idx)))
+(defun todos-edit-item-date-from-calendar ()
+  "Prompt for changes to current item's date and apply from Calendar."
+  (interactive)
+  (todos-edit-item-header 'calendar))
 
-(defun todos-set-count (type increment &optional category)
-  "Increment count of TYPE items in CATEGORY by INCREMENT.
-If CATEGORY is nil, default to the current category."
-  (let* ((cat (or category (todos-current-category)))
-        (counts (cdr (assoc cat todos-categories)))
-        (idx (cond ((eq type 'todo) 0)
-                   ((eq type 'diary) 1)
-                   ((eq type 'done) 2)
-                   ((eq type 'archived) 3))))
-    (aset counts idx (+ increment (aref counts idx)))))
+(defun todos-edit-item-date-is-today ()
+  "Set item date to today's date."
+  (interactive)
+  (todos-edit-item-header 'today))
+ 
+(defun todos-edit-item-time ()
+  "Prompt For and apply changes to current item's time."
+  (interactive)
+  (todos-edit-item-header 'timeonly))
 
-;; (defun todos-item-counts (operation &optional cat1 cat2)
-;;   "Update item counts in category CAT1 changed by OPERATION.
-;; If CAT1 is nil, update counts from the current category.  With
-;; non-nil CAT2 include specified counts from that category in the
-;; calculation for CAT1.
-;; After updating the item counts, update the `todos-categories' sexp."
-;;   (let* ((cat (or cat1 (todos-current-category))))
-;;     (cond ((eq type 'insert)
-;;        (todos-set-count 'todo 1 cat))
-;;       ((eq type 'diary)
-;;        (todos-set-count 'diary 1 cat))
-;;       ((eq type 'nondiary)
-;;        (todos-set-count 'diary -1 cat))
-;;       ((eq type 'delete)
-;;        ;; FIXME: ok if last done item was deleted?
-;;        (if (save-excursion
-;;              (re-search-backward (concat "^" (regexp-quote
-;;                                               todos-category-done)) nil t))
-;;            (todos-set-count 'done -1 cat)
-;;          (todos-set-count 'todo -1 cat)))
-;;       ((eq type 'done)
-;;        (unless (member (buffer-file-name) (funcall todos-files-function t))
-;;          (todos-set-count 'todo -1 cat))
-;;        (todos-set-count 'done 1 cat))
-;;       ((eq type 'undo)
-;;        (todos-set-count 'todo 1 cat)
-;;        (todos-set-count 'done -1 cat))
-;;       ((eq type 'archive1)
-;;        (todos-set-count 'archived 1 cat)
-;;        (todos-set-count 'done -1 cat))
-;;       ((eq type 'archive)
-;;        (if (member (buffer-file-name) (funcall todos-files-function t))
-;;            ;; In Archive file augment done count with cat's previous
-;;            ;; done count,
-;;            (todos-set-count 'done (todos-get-count 'done cat) cat)
-;;          ;; In Todos file augment archive count with cat's previous
-;;          ;; done count, and make the latter zero.
-;;          (todos-set-count 'archived (todos-get-count 'done cat) cat)
-;;          (todos-set-count 'done (- (todos-get-count 'done cat)) cat)))
-;;       ((eq type 'merge)
-;;        ;; Augment todo and done counts of cat by those of cat2.
-;;        (todos-set-count 'todo (todos-get-count 'todo cat2) cat)
-;;        (todos-set-count 'done (todos-get-count 'done cat2) cat)))
-;;     (todos-update-categories-sexp)))
+(defun todos-edit-item-diary-inclusion ()
+  "Change diary status of one or more todo items in this category.
+That is, insert `todos-nondiary-marker' if the candidate items
+lack this marking; otherwise, remove it.
 
-(defun todos-set-categories ()
-  "Set `todos-categories' from the sexp at the top of the file."
-  ;; New archive files created by `todos-move-category' are empty, which would
-  ;; make the sexp test fail and raise an error, so in this case we skip it.
-  (unless (zerop (buffer-size))
-    (save-excursion
-      (save-restriction
-       (widen)
-       (goto-char (point-min))
-       ;; todos-truncate-categories-list needs non-nil todos-categories.
-       (setq todos-categories-full
-             (if (looking-at "\(\(\"")
-                 (read (buffer-substring-no-properties
-                        (line-beginning-position)
-                        (line-end-position)))
-               (error "Invalid or missing todos-categories sexp"))
-             todos-categories todos-categories-full)))
-    (if (and todos-ignore-archived-categories
-            (eq major-mode 'todos-mode))
-       (todos-truncate-categories-list)
-      todos-categories-full)))
+If there are marked todo items, change the diary status of all
+and only these, otherwise change the diary status of the item at
+point."
+  (interactive)
+  (let ((buffer-read-only)
+       (marked (assoc (todos-current-category)
+                      todos-categories-with-marks)))
+    (catch 'stop
+      (save-excursion
+       (when marked (goto-char (point-min)))
+       (while (not (eobp))
+         (if (todos-done-item-p)
+             (throw 'stop (message "Done items cannot be edited"))
+           (unless (and marked (not (todos-marked-item-p)))
+             (let* ((beg (todos-item-start))
+                    (lim (save-excursion (todos-item-end)))
+                    (end (save-excursion
+                           (or (todos-time-string-matcher lim)
+                               (todos-date-string-matcher lim)))))
+               (if (looking-at (regexp-quote todos-nondiary-start))
+                   (progn
+                     (replace-match "")
+                     (search-forward todos-nondiary-end (1+ end) t)
+                     (replace-match "")
+                     (todos-set-count 'diary 1))
+                 (when end
+                   (insert todos-nondiary-start)
+                   (goto-char (1+ end))
+                   (insert todos-nondiary-end)
+                   (todos-set-count 'diary -1)))))
+           (unless marked (throw 'stop nil))
+           (todos-forward-item)))))
+    (todos-update-categories-sexp)))
 
-;; FIXME: currently unused -- make this a command to rebuild a corrupted
-;; todos-cats sexp ?
-(defun todos-make-categories-list (&optional force)
-  "Return an alist of Todos categories and their item counts.
-With non-nil argument FORCE parse the entire file to build the
-list; otherwise, get the value by reading the sexp at the top of
-the file."
-  (setq todos-categories nil)
+(defun todos-edit-category-diary-inclusion (arg)
+  "Make all items in this category diary items.
+With prefix ARG, make all items in this category non-diary
+items."
+  (interactive "P")
   (save-excursion
-    (save-restriction
-      (widen)
-      (goto-char (point-min))
-      (let (counts cat archive)
-       ;; FIXME: can todos-archives be too old here?
-       (unless (member buffer-file-name (funcall todos-files-function t))
-         (setq archive (concat (file-name-sans-extension
-                                todos-current-todos-file) ".toda")))
+    (goto-char (point-min))
+    (let ((todo-count (todos-get-count 'todo))
+         (diary-count (todos-get-count 'diary))
+         (buffer-read-only))
+      (catch 'stop
        (while (not (eobp))
-         (cond ((looking-at (concat (regexp-quote todos-category-beg)
-                                    "\\(.*\\)\n"))
-                (setq cat (match-string-no-properties 1))
-                ;; Counts for each category: [todo diary done archive]
-                (setq counts (make-vector 4 0))
-                (setq todos-categories
-                      (append todos-categories (list (cons cat counts))))
-                ;; todos-archives may be too old here (e.g. during
-                ;; todos-move-category).
-                (when (member archive (funcall todos-files-function t))
-                  (with-current-buffer (find-file-noselect archive)
-                    (widen)
-                    (goto-char (point-min))
-                    (when (re-search-forward
-                           (concat (regexp-quote todos-category-beg) cat)
-                           (point-max) t)
-                      (forward-line)
-                      (while (not (or (looking-at
-                                       (concat
-                                        (regexp-quote todos-category-beg)
-                                        "\\(.*\\)\n"))
-                                      (eobp)))
-                        (when (looking-at todos-done-string-start)
-                          (todos-set-count 'archived 1 cat))
-                        (forward-line))))))
-               ((looking-at todos-done-string-start)
-                (todos-set-count 'done 1 cat))
-               ((looking-at (concat "^\\("
-                                    (regexp-quote diary-nonmarking-symbol)
-                                    "\\)?" todos-date-pattern))
-                (todos-set-count 'diary 1 cat)
-                (todos-set-count 'todo 1 cat))
-               ((looking-at (concat todos-date-string-start todos-date-pattern))
-                (todos-set-count 'todo 1 cat))
-               ;; If first line is todos-categories list, use it and end loop
-               ;; unless forced by non-nil parameter `force' to scan whole file.
-               ((bobp)
-                (unless force
-                  (setq todos-categories (read (buffer-substring-no-properties
-                                                (line-beginning-position)
-                                                (line-end-position))))
-                  (goto-char (1- (point-max))))))
-         (forward-line)))))
-  todos-categories)
+         (if (todos-done-item-p)       ; We've gone too far.
+             (throw 'stop nil)
+           (let* ((beg (todos-item-start))
+                  (lim (save-excursion (todos-item-end)))
+                  (end (save-excursion
+                         (or (todos-time-string-matcher lim)
+                             (todos-date-string-matcher lim)))))
+             (if arg
+                 (unless (looking-at (regexp-quote todos-nondiary-start))
+                   (insert todos-nondiary-start)
+                   (goto-char (1+ end))
+                   (insert todos-nondiary-end))
+               (when (looking-at (regexp-quote todos-nondiary-start))
+                 (replace-match "")
+                 (search-forward todos-nondiary-end (1+ end) t)
+                 (replace-match "")))))
+         (todos-forward-item))
+       (unless (if arg (zerop diary-count) (= diary-count todo-count))
+         (todos-set-count 'diary (if arg
+                                     (- diary-count)
+                                   (- todo-count diary-count))))
+       (todos-update-categories-sexp)))))
 
-(defun todos-truncate-categories-list ()
-  "Return a truncated alist of Todos categories plus item counts.
-Categories containing only archived items are omitted.  This list
-is used in Todos mode when `todos-ignore-archived-categories' is
-non-nil."
-  (let (cats)
-    (dolist (catcons todos-categories-full cats)
-      (let ((cat (car catcons)))
-       (setq cats
-             (append cats
-                     (unless (and (zerop (todos-get-count 'todo cat))
-                                  (zerop (todos-get-count 'done cat))
-                                  (not (zerop (todos-get-count 'archived cat))))
-                       (list catcons))))))))
+(defun todos-edit-item-diary-nonmarking ()
+  "Change non-marking of one or more diary items in this category.
+That is, insert `diary-nonmarking-symbol' if the candidate items
+lack this marking; otherwise, remove it.
 
-(defun todos-update-categories-sexp ()
-  "Update the `todos-categories' sexp at the top of the file."
-  (let (buffer-read-only)
-    (save-excursion
-      (save-restriction
-       (widen)
-       (goto-char (point-min))
-       (if (looking-at (concat "^" (regexp-quote todos-category-beg)))
-           (progn (newline) (goto-char (point-min)))
-         ;; With empty buffer (e.g. with new archive in
-         ;; `todos-move-category') `kill-line' signals end of buffer.
-         (kill-region (line-beginning-position) (line-end-position)))
-       ;; FIXME
-       ;; (prin1 todos-categories (current-buffer))))))
-       (prin1 todos-categories-full (current-buffer))))))
+If there are marked todo items, change the non-marking status of
+all and only these, otherwise change the non-marking status of
+the item at point."
+  (interactive)
+  (let ((buffer-read-only)
+       (marked (assoc (todos-current-category)
+                      todos-categories-with-marks)))
+    (catch 'stop
+      (save-excursion
+       (when marked (goto-char (point-min)))
+       (while (not (eobp))
+         (if (todos-done-item-p)
+             (throw 'stop (message "Done items cannot be edited"))
+           (unless (and marked (not (todos-marked-item-p)))
+             (todos-item-start)
+             (unless (looking-at (regexp-quote todos-nondiary-start))
+               (if (looking-at (regexp-quote diary-nonmarking-symbol))
+                   (replace-match "")
+                 (insert diary-nonmarking-symbol))))
+           (unless marked (throw 'stop nil))
+           (todos-forward-item)))))))
 
-(defun todos-read-file-name (prompt &optional archive mustmatch)
-  "Choose and return the name of a Todos file, prompting with PROMPT.
-Show completions with TAB or SPC; the names are shown in short
-form but the absolute truename is returned.  With non-nil ARCHIVE
-return the absolute truename of a Todos archive file.  With non-nil
-MUSTMATCH the name of an existing file must be chosen;
-otherwise, a new file name is allowed."        ;FIXME: is this possible?
-  (unless (file-exists-p todos-files-directory)
-    (make-directory todos-files-directory))
-  (let* ((completion-ignore-case t)
-        (files (mapcar 'file-name-sans-extension
-                       (directory-files todos-files-directory nil
-                                        (if archive "\.toda$" "\.todo$"))))
-        (file (concat todos-files-directory
-                      (completing-read prompt files nil mustmatch)
-                      (if archive ".toda" ".todo"))))
-    (file-truename file)))
+(defun todos-edit-category-diary-nonmarking (arg)
+  "Add `diary-nonmarking-symbol' to all diary items in this category.
+With prefix ARG, remove `diary-nonmarking-symbol' from all diary
+items in this category."
+  (interactive "P")
+  (save-excursion
+    (goto-char (point-min))
+    (let (buffer-read-only)
+      (catch 'stop
+      (while (not (eobp))
+       (if (todos-done-item-p)         ; We've gone too far.
+           (throw 'stop nil)
+         (unless (looking-at (regexp-quote todos-nondiary-start))
+           (if arg
+               (when (looking-at (regexp-quote diary-nonmarking-symbol))
+                 (replace-match ""))
+             (unless (looking-at (regexp-quote diary-nonmarking-symbol))
+               (insert diary-nonmarking-symbol))))
+       (todos-forward-item)))))))
 
-(defun todos-read-category (prompt &optional mustmatch)
-  "Choose and return a category name, prompting with PROMPT.
-Show completions with TAB or SPC.  With non-nil MUSTMATCH the
-name must be that of an existing category; otherwise, a new
-category name is allowed, after checking its validity."
-  ;; Allow SPC to insert spaces, for adding new category names.
-  (let ((map minibuffer-local-completion-map))
-    (define-key map " " nil)
-    ;; 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)))
-          (completion-ignore-case todos-completion-ignore-case)
-          (category (completing-read prompt todos-categories nil
-                                     mustmatch nil history
-                                     (if todos-categories
-                                         (todos-current-category)
-                                       ;; Trigger prompt for initial category
-                                       ""))))
-      ;; FIXME: let "" return todos-current-category
-      (unless mustmatch
-       (when (and (not (assoc category categories))
-                  (y-or-n-p (format (concat "There is no category \"%s\" in "
-                                            "this file; add it? ") category)))
-         (todos-validate-category-name category)
-         (todos-add-category category)))
-      ;; Restore the original value of todos-categories.
-      (setq todos-categories categories)
-      category)))
+(defun todos-raise-item-priority (&optional lower)
+  "Raise priority of current item by moving it up by one item.
+With non-nil argument LOWER lower item's priority."
+  (interactive)
+  (unless (or (todos-done-item-p)
+             ;; Point is between todo and done items.
+             (looking-at "^$"))
+    (let (buffer-read-only)
+      (if (or (and lower
+                  (save-excursion
+                    ;; Can't lower final todo item.
+                    (todos-forward-item)
+                    (and (looking-at todos-item-start)
+                         (not (todos-done-item-p)))))
+             ;; Can't raise or lower todo item when it's the only one.
+             (> (count-lines (point-min) (point)) 0))
+         (let ((item (todos-item-string))
+               (marked (todos-marked-item-p)))
+           ;; In Todos Top Priorities mode, an item's priority can be changed
+           ;; wrt items in another category, but not wrt items in the same
+           ;; category.
+           (when (eq major-mode 'todos-filter-items-mode)
+             (let* ((regexp (concat todos-date-string-start todos-date-pattern
+                                    "\\( " diary-time-regexp "\\)?"
+                                    (regexp-quote todos-nondiary-end)
+                                    "?\\(?1: \\[\\(.+:\\)?.+\\]\\)"))
+                    (cat1 (save-excursion
+                           (re-search-forward regexp nil t)
+                           (match-string 1)))
+                    (cat2 (save-excursion
+                            (if lower
+                                (todos-forward-item)
+                              (todos-backward-item))
+                            (re-search-forward regexp nil t)
+                            (match-string 1))))
+               (if (string= cat1 cat2)
+                   ;; FIXME: better message
+                   (error (concat "Cannot change item's priority in its "
+                                  "category; do this in Todos mode")))))
+           (todos-remove-item)
+           (if lower (todos-forward-item) (todos-backward-item))
+           (todos-insert-with-overlays item)
+           ;; If item was marked, retore the mark.
+           (and marked (overlay-put (make-overlay (point) (point))
+                                    'before-string todos-item-mark)))
+       (message ""))))) ;FIXME: no message ?
 
-(defun todos-validate-category-name (cat)
-  "Check new category name CAT and when valid return it."
-  (let (prompt)
-    (while
-       (and (cond ((string= "" cat)
-                   ;; (if todos-categories
-                   ;;  (setq prompt "Enter a non-empty category name: ")
-                     ;; Prompt for initial category of a new Todos file.
-                     (setq prompt (concat "Initial category name ["
-                                          todos-initial-category "]: ")));)
-                  ((string-match "\\`\\s-+\\'" cat)
-                   (setq prompt
-                         "Enter a category name that is not only white space: "))
-                  ;; FIXME: add completion
-                  ((assoc cat todos-categories)
-                   (setq prompt "Enter a non-existing category name: ")))
-            (setq cat (if todos-categories
-                          (read-from-minibuffer prompt)
-                        ;; Offer default initial category name.
-                        (prin1-to-string
-                         (read-from-minibuffer prompt nil nil t nil
-                                               (list todos-initial-category))))))))
-  cat)
-
-;; (defun todos-read-category (prompt)
-;;   "Prompt with PROMPT for an existing category name and return it.
-;; Show completions with TAB or SPC."
-;;   ;; 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)))
-;;      (completion-ignore-case todos-completion-ignore-case)
-;;      (category (completing-read prompt todos-categories nil
-;;                                 mustmatch nil history)))
-;;     (setq category (completing-read prompt todos-categories nil t))
-;;     ;; Restore the original value of todos-categories.
-;;     (setq todos-categories categories)
-;;     category))
-
-;; (defun todos-new-category-name (prompt)
-;;   "Prompt with PROMPT for a new category name and return it."
-;;   (let ((map minibuffer-local-completion-map)
-;;     prompt-n)
-;;     ;; Allow SPC to insert spaces, for adding new category names.
-;;     (define-key map " " nil)
-;;     (while
-;;     ;; Validate entered category name.
-;;     (and (cond ((string= "" cat)
-;;                 (setq prompt-n
-;;                       (if todos-categories
-;;                           "Enter a non-empty category name: "
-;;                         ;; Prompt for initial category of a new Todos file.
-;;                         (concat "Initial category name ["
-;;                                 todos-initial-category "]: "))))
-;;                ((string-match "\\`\\s-+\\'" cat)
-;;                 (setq prompt-n
-;;                       "Enter a category name that is not only white space: "))
-;;                ((assoc cat todos-categories)
-;;                 (setq prompt-n "Enter a non-existing category name: ")))
-;;          (setq cat (if todos-categories
-;;                        (read-from-minibuffer prompt)
-;;                      ;; Offer default initial category name.
-;;                      (prin1-to-string
-;;                       (read-from-minibuffer
-;;                        (or prompt prompt-n) nil nil t nil
-;;                        (list todos-initial-category))))))
-;;       (setq prompt nil)))
-;;   cat)
-
-;; ;; Adapted from calendar-read-date and calendar-date-string.
-(defun todos-read-date ()
-  "Prompt for Gregorian date and return it in the current format.
-Also accepts `*' as an unspecified month, day, or year."
-  (let* ((year (calendar-read
-               ;; FIXME: maybe better like monthname with RET for current month
-                "Year (>0 or * for any year): "
-                (lambda (x) (or (eq x '*) (> x 0)))
-                (number-to-string (calendar-extract-year
-                                  (calendar-current-date)))))
-         (month-array (vconcat calendar-month-name-array (vector "*")))
-        (abbrevs (vconcat calendar-month-abbrev-array (vector "*")))
-         (completion-ignore-case t)
-        (monthname (completing-read
-                    "Month name (RET for current month, * for any month): "
-                    (mapcar 'list (append month-array nil))
-                    nil t nil nil
-                    (calendar-month-name (calendar-extract-month
-                                          (calendar-current-date)) t)))
-         (month (cdr (assoc-string
-                     monthname (calendar-make-alist month-array nil nil
-                                                    abbrevs))))
-         (last (if (= month 13)
-                  31                   ; FIXME: what about shorter months?
-                (let ((yr (if (eq year '*)
-                              1999     ; FIXME: no Feb. 29
-                            year)))
-                  (calendar-last-day-of-month month yr))))
-        day dayname)
-    (while (if (numberp day) (or (< day 0) (< last day)) (not (eq day '*)))
-      (setq day (read-from-minibuffer
-                (format "Day (1-%d or RET for today or * for any day): " last)
-                nil nil t nil
-                (number-to-string
-                 (calendar-extract-day (calendar-current-date))))))
-    (setq year (if (eq year '*) (symbol-name '*) (number-to-string year)))
-    (setq day (if (eq day '*) (symbol-name '*) (number-to-string day)))
-    ;; FIXME: make abbreviation customizable
-    (setq monthname
-         (or (and (= month 13) "*")
-             (calendar-month-name (calendar-extract-month (list month day year))
-                                  t)))
-    (mapconcat 'eval calendar-date-display-form "")))
+(defun todos-lower-item-priority ()
+  "Lower priority of current item by moving it down by one item."
+  (interactive)
+  (todos-raise-item-priority t))
 
-(defun todos-read-dayname ()
-  "Choose name of a day of the week with completion and return it."
-  (let ((completion-ignore-case t))
-    (completing-read "Enter a day name: "
-                    (append calendar-day-name-array nil)
-                    nil t)))
-  
-(defun todos-read-time ()
-  "Prompt for and return a valid clock time as a string.
-Valid time strings are those matching `diary-time-regexp'."
-  (let (valid answer)
-    (while (not valid)
-      (setq answer (read-from-minibuffer
-                   "Enter a clock time (or return for none): "))
-      (when (or (string= "" answer)
-               (string-match diary-time-regexp answer))
-       (setq valid t)))
-    answer))
+;; FIXME: incorporate todos-(raise|lower)-item-priority ?
+;; FIXME: does this DTRT in todos-categories-mode?
+(defun todos-set-item-priority (item cat &optional new)
+  "Set todo ITEM's priority in category CAT, moving item as needed.
+Interactively, the item and the category are the current ones,
+and the priority is a number between 1 and the number of items in
+the category.  Non-interactively with argument NEW, the lowest
+priority is one more than the number of items in CAT."
+  (interactive (list (todos-item-string) (todos-current-category)))
+  (unless (called-interactively-p t)
+    (todos-category-number cat)
+    (todos-category-select))
+  (let* ((todo (todos-get-count 'todo cat))
+        (maxnum (if new (1+ todo) todo))
+        (buffer-read-only)
+        priority candidate prompt)
+    (unless (zerop todo)
+      (while (not priority)
+       (setq candidate
+             (string-to-number (read-from-minibuffer
+                                (concat prompt
+                                        (format "Set item priority (1-%d): "
+                                                maxnum)))))
+       (setq prompt
+             (when (or (< candidate 1) (> candidate maxnum))
+               (format "Priority must be an integer between 1 and %d.\n"
+                       maxnum)))
+       (unless prompt (setq priority candidate)))
+      ;; Interactively, just relocate the item within its category.
+      (when (called-interactively-p) (todos-remove-item))
+      (goto-char (point-min))
+      (unless (= priority 1) (todos-forward-item (1- priority))))
+    (todos-insert-with-overlays item)))
 
-;;; Sorting and display routines for todos-categories-mode.
+(defun todos-move-item (&optional file)
+  "Move at least one todo item to another category.
 
-(defun todos-display-categories (&optional sortkey)
-  "Display a table of the current file's categories and item counts.
+If there are marked items, move all of these; otherwise, move
+the item at point.
 
-In the initial display the categories are numbered, indicating
-their current order for navigating by \\[todos-forward-category]
-and \\[todos-backward-category].  You can persistantly change the
-order of the category at point by typing \\[todos-raise-category]
-or \\[todos-lower-category].
+With non-nil argument FILE, first prompt for another Todos file and
+then a category in that file to move the item or items to.
 
-The labels above the category names and item counts are buttons,
-and clicking these changes the display: sorted by category name
-or by the respective item counts (alternately descending or
-ascending).  In these displays the categories are not numbered
-and \\[todos-raise-category] and \\[todos-lower-category] are
-disabled.  (Programmatically, the sorting is triggered by passing
-a non-nil SORTKEY argument.)
+If the chosen category is not one of the existing categories,
+then it is created and the item(s) become(s) the first
+entry/entries in that category."
+  (interactive)
+  (unless (or (todos-done-item-p)
+             ;; Point is between todo and done items.
+             (looking-at "^$"))
+    (let* ((buffer-read-only)
+          (file1 todos-current-todos-file)
+          (cat1 (todos-current-category))
+          (marked (assoc cat1 todos-categories-with-marks))
+          (num todos-category-number)
+          (item (todos-item-string))
+          (diary-item (todos-diary-item-p))
+          (omark (save-excursion (todos-item-start) (point-marker)))
+          (file2 (if file
+                     (todos-read-file-name "Choose a Todos file: " nil t)
+                   file1))
+          (count 0)
+          (count-diary 0)
+          cat2 nmark)
+      (set-buffer (find-file-noselect file2))
+      (setq cat2 (let* ((pl (if (and marked (> (cdr marked) 1)) "s" ""))
+                       (name (todos-read-category
+                              (concat "Move item" pl " to category: ")))
+                       (prompt (concat "Choose a different category than "
+                                       "the current one\n(type `"
+                                       (key-description
+                                        (car (where-is-internal
+                                              'todos-set-item-priority)))
+                                       "' to reprioritize item "
+                                       "within the same category): ")))
+                  (while (equal name cat1)
+                    (setq name (todos-read-category prompt)))
+                  name))
+      (set-buffer (get-file-buffer file1))
+      (if marked
+         (progn
+          (setq item nil)
+          (goto-char (point-min))
+          (while (not (eobp))
+            (when (todos-marked-item-p)
+              (setq item (concat item (todos-item-string) "\n"))
+              (setq count (1+ count))
+              (when (todos-diary-item-p)
+                (setq count-diary (1+ count-diary))))
+            (todos-forward-item))
+          ;; Chop off last newline.
+          (setq item (substring item 0 -1)))
+       (setq count 1)
+       (when (todos-diary-item-p) (setq count-diary 1)))
+      (set-window-buffer (selected-window)
+                        (set-buffer (find-file-noselect file2)))
+      (unless (assoc cat2 todos-categories) (todos-add-category cat2))
+      (todos-set-item-priority item cat2 t)
+      (setq nmark (point-marker))
+      (todos-set-count 'todo count)
+      (todos-set-count 'diary count-diary)
+      (todos-update-categories-sexp)
+      (with-current-buffer (get-file-buffer file1)
+       (save-excursion
+         (save-restriction
+           (widen)
+           (goto-char omark)
+           (if marked
+               (let (beg end)
+                 (setq item nil)
+                 (re-search-backward
+                  (concat "^" (regexp-quote todos-category-beg)) nil t)
+                 (forward-line)
+                 (setq beg (point))
+                 (re-search-forward
+                  (concat "^" (regexp-quote todos-category-done)) nil t)
+                 (setq end (match-beginning 0))
+                 (goto-char beg)
+                 (while (< (point) end)
+                   (if (todos-marked-item-p)
+                       (todos-remove-item)
+                     (todos-forward-item))))
+             (todos-remove-item))))
+       (todos-set-count 'todo (- count) cat1)
+       (todos-set-count 'diary (- count-diary) cat1)
+       (todos-update-categories-sexp))
+      (set-window-buffer (selected-window)
+                        (set-buffer (find-file-noselect file2)))
+      (setq todos-category-number (todos-category-number cat2))
+      (todos-category-select)
+      (goto-char nmark))))
 
-In addition, the lines with the category names and item counts
-are buttonized, and pressing one of these button jumps to the
-category in Todos mode (or Todos Archive mode, for categories
-containing only archived items, provided user option
-`todos-ignore-archived-categories' is non-nil.  These categories
-are shown in `todos-archived-only' face."
+(defun todos-move-item-to-file ()
+  "Move the current todo item to a category in another Todos file."
   (interactive)
-  (unless (eq major-mode 'todos-categories-mode)
-    (setq todos-global-current-todos-file (or todos-current-todos-file
-                                             todos-default-todos-file)))
-  (let* ((cats0 (if (and todos-ignore-archived-categories
-                        (not (eq major-mode 'todos-categories-mode)))
-                   todos-categories-full
-                 todos-categories))
-        (cats (todos-sort cats0 sortkey))
-        (archive (member todos-current-todos-file todos-archives))
-        ;; `num' is used by todos-insert-category-line.
-        (num 0))
-    (set-window-buffer (selected-window)
-                      (set-buffer (get-buffer-create todos-categories-buffer)))
-    (let (buffer-read-only)
-      (erase-buffer)
-      (kill-all-local-variables)
-      (todos-categories-mode)
-      ;; FIXME: add usage tips?
-      (insert (format "Category counts for Todos file \"%s\"."
-                     (file-name-sans-extension
-                      (file-name-nondirectory todos-current-todos-file))))
-      (newline 2)
-      ;; Make space for the column of category numbers.
-      (insert (make-string (+ 4 (length todos-categories-number-separator)) 32))
-      ;; Add the category and item count buttons (if this is the list of
-      ;; categories in an archive, show only done item counts).
-      (save-excursion
-       (todos-insert-sort-button todos-categories-category-label)
-       (if (member todos-current-todos-file todos-archives)
-           (insert (concat (make-string 6 32)
-                           (format "%s" todos-categories-archived-label)))
-         (insert (make-string 3 32))
-         (todos-insert-sort-button todos-categories-todo-label)
-         (insert (make-string 2 32))
-         (todos-insert-sort-button todos-categories-diary-label)
-         (insert (make-string 2 32))
-         (todos-insert-sort-button todos-categories-done-label)
-         (insert (make-string 2 32))
-         (todos-insert-sort-button todos-categories-archived-label))
-       (newline 2)
-       ;; Fill in the table with buttonized lines, each showing a category and
-       ;; its item counts.
-       (mapc (lambda (cat) (todos-insert-category-line cat sortkey))
-             (mapcar 'car cats))
-       (newline)
-       ;; Add a line showing item count totals.
-       (insert (make-string (+ 4 (length todos-categories-number-separator)) 32)
-               (todos-padded-string todos-categories-totals-label)
-               (mapconcat
-                (lambda (elt)
-                  (concat
-                   (make-string (1+ (/ (length (car elt)) 2)) 32)
-                   (format "%3d" (nth (cdr elt) (todos-total-item-counts)))
-                   ;; Add an extra space if label length is odd (using
-                   ;; definition of oddp from cl.el).
-                   (if (eq (logand (length (car elt)) 1) 1) " ")))
-                (if archive
-                    (list (cons todos-categories-done-label 2))
-                  (list (cons todos-categories-todo-label 0)
-                        (cons todos-categories-diary-label 1)
-                        (cons todos-categories-done-label 2)
-                        (cons todos-categories-archived-label 3)))
-                ""))))
-    (setq buffer-read-only t)))
-
-;; ;; FIXME: make this toggle with todos-display-categories
-;; (defun todos-display-categories-alphabetically ()
-;;   ""
-;;   (interactive)
-;;   (todos-display-sorted 'alpha))
+  (todos-move-item t))
 
-;; ;; FIXME: provide key bindings for these or delete them
-;; (defun todos-display-categories-sorted-by-todo ()
-;;   ""
-;;   (interactive)
-;;   (todos-display-sorted 'todo))
+(defun todos-move-item-to-diary ()
+  "Move one or more items in current category to the diary file.
 
-;; (defun todos-display-categories-sorted-by-diary ()
-;;   ""
-;;   (interactive)
-;;   (todos-display-sorted 'diary))
+If there are marked items, move all of these; otherwise, move
+the item at point."
+  (interactive)
+  ;; FIXME
+  )
 
-;; (defun todos-display-categories-sorted-by-done ()
-;;   ""
-;;   (interactive)
-;;   (todos-display-sorted 'done))
+;; FIXME: make adding date customizable, and make this and time customization
+;; overridable via double prefix arg ??
+(defun todos-item-done (&optional arg)
+  "Tag at least one item in this category as done and hide it.
+
+With prefix argument ARG prompt for a comment and append it to
+the done item; this is only possible if there are no marked
+items.  If there are marked items, tag all of these with
+`todos-done-string' plus the current date and, if
+`todos-always-add-time-string' is non-nil, the current time;
+otherwise, just tag the item at point.  Items tagged as done are
+relocated to the category's (by default hidden) done section."
+  (interactive "P")
+  (let* ((cat (todos-current-category))
+        (marked (assoc cat todos-categories-with-marks)))
+    (unless (or (todos-done-item-p) 
+               (and (looking-at "^$") (not marked)))
+      (let* ((date-string (calendar-date-string (calendar-current-date) t t))
+            (time-string (if todos-always-add-time-string
+                             (concat " " (substring (current-time-string) 11 16))
+                           ""))
+            (done-prefix (concat "[" todos-done-string date-string time-string
+                                 "] "))
+            (comment (and arg (not marked) (read-string "Enter a comment: ")))
+            (item-count 0)
+            (diary-count 0)
+            item done-item
+            (buffer-read-only))
+       (and marked (goto-char (point-min)))
+       (catch 'done
+         (while (not (eobp))
+           (if (or (not marked) (and marked (todos-marked-item-p)))
+               (progn
+                 (setq item (todos-item-string))
+                 (setq done-item (cond (marked
+                                        (concat done-item done-prefix item "\n"))
+                                       (comment
+                                        (concat done-prefix item " ["
+                                                todos-comment-string
+                                                ": " comment "]"))
+                                       (t
+                                        (concat done-prefix item))))
+                 (setq item-count (1+ item-count))
+                 (when (todos-diary-item-p)
+                   (setq diary-count (1+ diary-count)))
+                 (todos-remove-item)
+                 (unless marked (throw 'done nil)))
+             (todos-forward-item))))
+       (when marked
+         ;; Chop off last newline of done item string.
+         (setq done-item (substring done-item 0 -1))
+         (remove-overlays (point-min) (point-max) 'before-string todos-item-mark)
+         (setq todos-categories-with-marks
+               (assq-delete-all cat todos-categories-with-marks)))
+       (save-excursion
+         (widen)
+         (re-search-forward
+          (concat "^" (regexp-quote todos-category-done)) nil t)
+         (forward-char)
+         (insert done-item "\n"))
+       (todos-set-count 'todo (- item-count))
+       (todos-set-count 'done item-count)
+       (todos-set-count 'diary (- diary-count))
+       (todos-update-categories-sexp)
+       (save-excursion (todos-category-select))))))
+
+;; FIXME: only if there's no comment, or edit an existing comment?
+(defun todos-comment-done-item ()
+  "Add a comment to this done item."
+  (interactive)
+  (when (todos-done-item-p)
+    (let ((comment (read-string "Enter a comment: "))
+         buffer-read-only)
+      (todos-item-end)
+      (insert " [" todos-comment-string ": " comment "]"))))
 
-;; (defun todos-display-categories-sorted-by-archived ()
-;;   ""
-;;   (interactive)
-;;   (todos-display-sorted 'archived))
+;; FIXME: implement this or done item editing?
+(defun todos-uncomment-done-item ()
+  ""
+  )
 
-(defun todos-longest-category-name-length (categories)
-  "Return the length of the longest name in list CATEGORIES."
-  (let ((longest 0))
-    (dolist (c categories longest)
-      (setq longest (max longest (length c))))))
+;; FIXME: delete comment from restored item or just leave it up to user?
+(defun todos-item-undo ()
+  "Restore this done item to the todo section of this category."
+  (interactive)
+  (when (todos-done-item-p)
+    (let* ((buffer-read-only)
+          (done-item (todos-item-string))
+          (opoint (point))
+          (orig-mrk (progn (todos-item-start) (point-marker)))
+          ;; Find the end of the date string added upon making item done.
+          (start (search-forward "] "))
+          (item (buffer-substring start (todos-item-end)))
+          undone)
+      (todos-remove-item)
+      ;; If user cancels before setting new priority, then restore everything.
+      (unwind-protect
+         (progn
+           (todos-set-item-priority item (todos-current-category) t)
+           (setq undone t)
+           (todos-set-count 'todo 1)
+           (todos-set-count 'done -1)
+           (and (todos-diary-item-p) (todos-set-count 'diary 1))
+           (todos-update-categories-sexp))
+       (unless undone
+         (widen)
+         (goto-char orig-mrk)
+         (todos-insert-with-overlays done-item)
+         (let ((todos-show-with-done t))
+           (todos-category-select)
+           (goto-char opoint)))
+       (set-marker orig-mrk nil)))))
 
-(defun todos-padded-string (str)
-  "Return string STR padded with spaces.
-The placement of the padding is determined by the value of user
-option `todos-categories-align'."
-  (let* ((categories (mapcar 'car todos-categories))
-        (len (max (todos-longest-category-name-length categories)
-                  (length todos-categories-category-label)))
-        (strlen (length str))
-        (strlen-odd (eq (logand strlen 1) 1)) ; oddp from cl.el
-        (padding (max 0 (/ (- len strlen) 2)))
-        (padding-left (cond ((eq todos-categories-align 'left) 0)
-                            ((eq todos-categories-align 'center) padding)
-                            ((eq todos-categories-align 'right)
-                             (if strlen-odd (1+ (* padding 2)) (* padding 2)))))
-        (padding-right (cond ((eq todos-categories-align 'left)
-                              (if strlen-odd (1+ (* padding 2)) (* padding 2)))
-                             ((eq todos-categories-align 'center)
-                              (if strlen-odd (1+ padding) padding))
-                             ((eq todos-categories-align 'right) 0))))
-    (concat (make-string padding-left 32) str (make-string padding-right 32))))
+(defun todos-archive-done-item-or-items (&optional all)
+  "Archive at least one done item in this category.
 
-(defvar todos-descending-counts nil
-  "List of keys for category counts sorted in descending order.")
+If there are marked done items (and no marked todo items),
+archive all of these; otherwise, with non-nil argument ALL,
+archive all done items in this category; otherwise, archive the
+done item at point.
 
-(defun todos-sort (list &optional key)
-  "Return a copy of LIST, possibly sorted according to KEY."
-  (let* ((l (copy-sequence list))
-        (fn (if (eq key 'alpha)
-                  (lambda (x) (upcase x)) ; Alphabetize case insensitively.
-                (lambda (x) (todos-get-count key x))))
-        (descending (member key todos-descending-counts))
-        (cmp (if (eq key 'alpha)
-                 'string<
-               (if descending '< '>)))
-        (pred (lambda (s1 s2) (let ((t1 (funcall fn (car s1)))
-                                    (t2 (funcall fn (car s2))))
-                                (funcall cmp t1 t2)))))
-    (when key
-      (setq l (sort l pred))
-      (if descending
-         (setq todos-descending-counts
-               (delete key todos-descending-counts))
-       (push key todos-descending-counts)))
-    l))
+If the archive of this file does not exist, it is created.  If
+this category does not exist in the archive, it is created."
+  (interactive)
+  (when (not (member (buffer-file-name) (funcall todos-files-function t)))
+    (if (and all (zerop (todos-get-count 'done)))
+       (message "No done items in this category")
+      (catch 'end
+       (let* ((cat (todos-current-category))
+              (tbuf (current-buffer))
+              (marked (assoc cat todos-categories-with-marks))
+              (afile (concat (file-name-sans-extension
+                              todos-current-todos-file) ".toda"))
+              (archive (if (file-exists-p afile)
+                           (find-file-noselect afile t)
+                         (progn
+                           ;; todos-add-category requires an exisiting file...
+                           (with-current-buffer (get-buffer-create afile)
+                             (erase-buffer)
+                             (write-region (point-min) (point-max) afile
+                                           nil 'nomessage nil t)))
+                         ;; ...but the file still lacks a categories sexp, so
+                         ;; visiting the file would barf on todos-set-categories,
+                         ;; hence we just return the buffer.
+                         (get-buffer afile)))
+              (item (and (todos-done-item-p) (concat (todos-item-string) "\n")))
+              (count 0)
+              marked-items beg end all-done
+              buffer-read-only)
+         (cond
+          (marked
+           (save-excursion
+             (goto-char (point-min))
+             (while (not (eobp))
+               (if (todos-marked-item-p)
+                   (if (not (todos-done-item-p))
+                       (throw 'end (message "Only done items can be archived"))
+                     (concat marked-items (todos-item-string) "\n")
+                     (setq count (1+ count)))
+                 (todos-forward-item)))))
+          (all
+           (if (y-or-n-p "Archive all done items in this category? ")
+               (save-excursion
+                 (save-restriction
+                   (goto-char (point-min))
+                   (widen)
+                   (setq beg (progn
+                               (re-search-forward todos-done-string-start nil t)
+                               (match-beginning 0))
+                         end (if (re-search-forward
+                                  (concat "^" (regexp-quote todos-category-beg))
+                                  nil t)
+                                 (match-beginning 0)
+                               (point-max))
+                         all-done (buffer-substring beg end)
+                         count (todos-get-count 'done))))
+             (throw 'end nil))))
+         (when (or marked all item)
+           (with-current-buffer archive
+             (let ((current todos-global-current-todos-file)
+                   (buffer-read-only))
+               (widen)
+               (goto-char (point-min))
+               (if (progn
+                     (re-search-forward
+                      (concat "^" (regexp-quote (concat todos-category-beg cat)))
+                      nil t)
+                     (re-search-forward (regexp-quote todos-category-done) nil t))
+                   (forward-char)
+                 ;; todos-add-category uses t-c-t-f, so temporarily set it.
+                 (setq todos-current-todos-file afile)
+                 (todos-add-category cat)
+                 (goto-char (point-max)))
+               (insert (cond (marked marked-items)
+                             (all all-done)
+                             (item)))
+               (todos-set-count 'done (if (or marked all) count 1))
+               (todos-update-categories-sexp)
+               ;; Save to file now (using write-region in order not to visit
+               ;; afile) so we can visit it later with todos-view-archived-items
+               ;; or todos-show-archive.
+               (write-region nil nil afile)
+               (setq todos-current-todos-file current)))
+           (with-current-buffer tbuf
+             (cond ((or marked item)
+                    (and marked (goto-char (point-min)))
+                    (catch 'done
+                      (while (not (eobp))
+                        (if (or (and marked (todos-marked-item-p)) item)
+                            (progn
+                              (todos-remove-item)
+                              (todos-set-count 'done -1)
+                              (todos-set-count 'archived 1)
+                              ;; Don't leave point below last item.
+                              (and item (bolp) (eolp) (< (point-min) (point-max))
+                                   (todos-backward-item))
+                              (when item 
+                                (throw 'done (setq item nil))))
+                          (todos-forward-item)))))
+                   (all
+                    (remove-overlays beg end)
+                    (delete-region beg end)
+                    (todos-set-count 'done (- count))
+                    (todos-set-count 'archived count)))
+             (when marked
+               (remove-overlays (point-min) (point-max)
+                                'before-string todos-item-mark)
+               (setq todos-categories-with-marks
+                     (assq-delete-all cat todos-categories-with-marks))
+               (goto-char opoint))
+             (todos-update-categories-sexp)
+             (todos-prefix-overlays)
+             ;; FIXME: Heisenbug: item displays mark -- but not when edebugging
+             (remove-overlays (point-min) (point-max)
+                              'before-string todos-item-mark)))
+         (display-buffer (find-file-noselect afile) t)
+         ;; FIXME: how to avoid switch-to-buffer and still get tbuf above
+         ;; afile?  What about pop-to-buffer-same-window in recent trunk?
+         (switch-to-buffer tbuf))))))
 
-(defun todos-display-sorted (type)
-  "Keep point on the TYPE count sorting button just clicked."
-  (let ((opoint (point)))
-    (todos-display-categories type)
-    (goto-char opoint)))
+(defun todos-archive-category-done-items ()
+  "Move all done items in this category to its archive."
+  (interactive)
+  (todos-archive-done-item-or-items t))
 
-(defun todos-label-to-key (label)
-  "Return symbol for sort key associated with LABEL."
-  (let (key)
-    (cond ((string= label todos-categories-category-label)
-          (setq key 'alpha))
-         ((string= label todos-categories-todo-label)
-          (setq key 'todo))
-         ((string= label todos-categories-diary-label)
-          (setq key 'diary))
-         ((string= label todos-categories-done-label)
-          (setq key 'done))
-         ((string= label todos-categories-archived-label)
-          (setq key 'archived)))
-    key))
+(defun todos-unarchive-items (&optional all)
+  "Unarchive at least one item in this archive category.
 
-(defun todos-insert-sort-button (label)
-  "Insert button for displaying categories sorted by item counts.
-LABEL determines which type of count is sorted."
-  (setq str (if (string= label todos-categories-category-label)
-               (todos-padded-string label)
-             label))
-  (setq beg (point))
-  (setq end (+ beg (length str)))
-  (insert-button str 'face nil
-                'action
-                `(lambda (button)
-                   (let ((key (todos-label-to-key ,label)))
-                     (if (and (member key todos-descending-counts)
-                              (eq key 'alpha))
-                         (progn
-                           (todos-display-categories)
-                           (setq todos-descending-counts
-                                 (delete key todos-descending-counts)))
-                       (todos-display-sorted key)))))
-  (setq ovl (make-overlay beg end))
-  (overlay-put ovl 'face 'todos-button))
+If there are marked items, unarchive all of these; otherwise,
+with non-nil argument ALL, unarchive all items in this category;
+otherwise, unarchive the item at point.
 
-(defun todos-total-item-counts ()
-  "Return a list of total item counts for the current file."
-  (mapcar (lambda (i) (apply '+ (mapcar (lambda (l) (aref l i))
-                                       (mapcar 'cdr todos-categories))))
-         (list 0 1 2 3)))
+Unarchived items are restored as done items to the corresponding
+category in the Todos file, inserted at the end of done section.
+If all items in the archive category were restored, the category
+is deleted from the archive.  If this was the only category in the
+archive, the archive file is deleted."
+  (interactive)
+  (when (member (buffer-file-name) (funcall todos-files-function t))
+    (catch 'end
+      (let* ((buffer-read-only nil)
+            (tbuf (find-file-noselect
+                   (concat (file-name-sans-extension todos-current-todos-file)
+                           ".todo") t))
+            (cat (todos-current-category))
+            (marked (assoc cat todos-categories-with-marks))
+            (item (concat (todos-item-string) "\n"))
+            (all-items (buffer-substring (point-min) (point-max)))
+            (all-count (todos-get-count 'done))
+            marked-items marked-count)
+       (save-excursion
+         (goto-char (point-min))
+         (while (not (eobp))
+           (when (todos-marked-item-p)
+             (concat marked-items (todos-item-string) "\n")
+             (setq marked-count (1+ marked-count)))
+           (todos-forward-item)))
+       ;; Restore items to end of category's done section and update counts.
+       (with-current-buffer tbuf
+         (let (buffer-read-only)
+           (widen)
+           (goto-char (point-min))
+           (re-search-forward (concat "^" (regexp-quote
+                                           (concat todos-category-beg cat)))
+                              nil t)
+           (if (re-search-forward (concat "^" (regexp-quote todos-category-beg))
+                                  nil t)
+               (goto-char (match-beginning 0))
+             (goto-char (point-max)))
+           (cond (marked
+                  (insert marked-items)
+                  (todos-set-count 'done marked-count)
+                  (todos-set-count 'archived (- marked-count)))
+                 (all
+                  (if (y-or-n-p (concat "Restore this category's items "
+                                        "to Todos file as done items "
+                                        "and delete this category? "))
+                      (progn (insert all-items)
+                             (todos-set-count 'done all-count)
+                             (todos-set-count 'archived (- all-count)))
+                    (throw 'end nil)))
+                 (t
+                  (insert item)
+                  (todos-set-count 'done 1)
+                  (todos-set-count 'archived -1)))
+           (todos-update-categories-sexp)))
+       ;; Delete restored items from archive.
+       (cond ((or marked item)
+              (and marked (goto-char (point-min)))
+              (catch 'done
+                (while (not (eobp))
+                  (if (or (and marked (todos-marked-item-p)) item)
+                      (progn
+                        (todos-remove-item)
+                        (todos-set-count 'done -1)
+                        ;; Don't leave point below last item.
+                        (and item (bolp) (eolp) (< (point-min) (point-max))
+                             (todos-backward-item))
+                        (when item 
+                          (throw 'done (setq item nil))))
+                    (todos-forward-item)))))
+             (all
+              (remove-overlays (point-min) (point-max))
+              (delete-region (point-min) (point-max))
+              (todos-set-count 'done (- all-count))))
+       ;; If that was the last category in the archive, delete the whole file.
+       (if (= (length todos-categories) 1)
+           (progn
+             (delete-file todos-current-todos-file)
+             ;; Don't bother confirming killing the archive buffer.
+             (set-buffer-modified-p nil)
+             (kill-buffer))
+         ;; Otherwise, if the archive category is now empty, delete it.
+         (when (eq (point-min) (point-max))
+           (widen)
+           (let ((beg (re-search-backward
+                       (concat "^" (regexp-quote todos-category-beg) cat)
+                       nil t))
+                 (end (if (re-search-forward
+                           (concat "^" (regexp-quote todos-category-beg))
+                           nil t 2)
+                          (match-beginning 0)
+                        (point-max))))
+             (remove-overlays beg end)
+             (delete-region beg end)
+             (setq todos-categories (delete (assoc cat todos-categories)
+                                            todos-categories))
+             (todos-update-categories-sexp))))
+       ;; Visit category in Todos file and show restored done items.
+       (let ((tfile (buffer-file-name tbuf))
+             (todos-show-with-done t))
+         (set-window-buffer (selected-window)
+                            (set-buffer (find-file-noselect tfile)))
+         (todos-category-number cat)
+         (todos-show)
+         (message "Items unarchived."))))))
 
-(defun todos-insert-category-line (cat &optional nonum)
-  "Insert button displaying category CAT's name and item counts.
-With non-nil argument NONUM show only these; otherwise, insert a
-number in front of the button indicating the category's priority.
-The number and the category name are separated by the string
-which is the value of the user option
-`todos-categories-number-separator'."
-  (let* ((archive (member todos-current-todos-file todos-archives))
-       (str (todos-padded-string cat))
-       (opoint (point)))
-    ;; num is declared in caller.
-    (setq num (1+ num))
-    (insert-button
-     (concat (if nonum
-                (make-string (+ 4 (length todos-categories-number-separator))
-                             32)
-              (format " %3d%s" num todos-categories-number-separator))
-            str
-            (mapconcat (lambda (elt)
-                         (concat
-                          (make-string (1+ (/ (length (car elt)) 2)) 32) ; label
-                          (format "%3d" (todos-get-count (cdr elt) cat)) ; count
-                          ;; Add an extra space if label length is odd
-                          ;; (using def of oddp from cl.el).
-                          (if (eq (logand (length (car elt)) 1) 1) " ")))
-                       (if archive
-                           (list (cons todos-categories-done-label 'done))
-                         (list (cons todos-categories-todo-label 'todo)
-                               (cons todos-categories-diary-label 'diary)
-                               (cons todos-categories-done-label 'done)
-                               (cons todos-categories-archived-label
-                                     'archived)))
-                         ""))
-     'face (if (and todos-ignore-archived-categories
-                   (zerop (todos-get-count 'todo cat))
-                   (zerop (todos-get-count 'done cat))
-                   (not (zerop (todos-get-count 'archived cat))))
-              'todos-archived-only
-            nil)
-     'action `(lambda (button) (let ((buf (current-buffer)))
-                                (todos-jump-to-category ,cat)
-                                (kill-buffer buf))))
-    ;; Highlight the sorted count column.
-    (let* ((beg (+ opoint 6 (length str)))
-          end ovl)
-      (cond ((eq nonum 'todo)
-            (setq beg (+ beg 1 (/ (length todos-categories-todo-label) 2))))
-           ((eq nonum 'diary)
-            (setq beg (+ beg 1 (length todos-categories-todo-label)
-                          2 (/ (length todos-categories-diary-label) 2))))
-           ((eq nonum 'done)
-            (setq beg (+ beg 1 (length todos-categories-todo-label)
-                          2 (length todos-categories-diary-label)
-                          2 (/ (length todos-categories-done-label) 2))))
-           ((eq nonum 'archived)
-            (setq beg (+ beg 1 (length todos-categories-todo-label)
-                          2 (length todos-categories-diary-label)
-                          2 (length todos-categories-done-label)
-                          2 (/ (length todos-categories-archived-label) 2)))))
-      (unless (= beg (+ opoint 6 (length str)))
-       (setq end (+ beg 4))
-       (setq ovl (make-overlay beg end))
-       (overlay-put ovl 'face 'todos-sorted-column)))
-    (newline)))
+(defun todos-unarchive-category ()
+  "Unarchive all items in this category.  See `todos-unarchive-items'."
+  (interactive)
+  (todos-unarchive-items t))
 
 (provide 'todos)
 
 ;;; todos.el ends here
 
+;; ---------------------------------------------------------------------------
 ;;; necessitated adaptations to diary-lib.el
 
 ;; (defun diary-goto-entry (button)