X-Git-Url: http://cgit.sxemacs.org/?a=blobdiff_plain;f=lisp%2Fgnus-topic.el;h=88fe35d8b0c230e10c09e8d68291fda0e7169caf;hb=d6b44b3c5ff2acbf182fc1223a610dbf9af98ba4;hp=a8c8e93d6ae9493ee71b2294b774cdca906ea525;hpb=964df6c80c3b57f2e378f847f0ed72692a1df629;p=gnus

diff --git a/lisp/gnus-topic.el b/lisp/gnus-topic.el
index a8c8e93d6..88fe35d8b 100644
--- a/lisp/gnus-topic.el
+++ b/lisp/gnus-topic.el
@@ -1,8 +1,9 @@
-;; gnus-topic.el --- a folding minor mode for Gnus group buffers
-;; Copyright (C) 1995,96 Free Software Foundation, Inc.
+;;; gnus-topic.el --- a folding minor mode for Gnus group buffers
+;; Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000
+;;        Free Software Foundation, Inc.
 
 ;; Author: Ilja Weis <kult@uni-paderborn.de>
-;;	Lars Magne Ingebrigtsen <larsi@ifi.uio.no>
+;;	Lars Magne Ingebrigtsen <larsi@gnus.org>
 ;; Keywords: news
 
 ;; This file is part of GNU Emacs.
@@ -26,16 +27,26 @@
 
 ;;; Code:
 
-(require 'gnus)
 (eval-when-compile (require 'cl))
 
+(require 'gnus)
+(require 'gnus-group)
+(require 'gnus-start)
+(require 'gnus-util)
+
+(defgroup gnus-topic nil
+  "Group topics."
+  :group 'gnus-group)
+
 (defvar gnus-topic-mode nil
   "Minor mode for Gnus group buffers.")
 
-(defvar gnus-topic-mode-hook nil
-  "Hook run in topic mode buffers.")
+(defcustom gnus-topic-mode-hook nil
+  "Hook run in topic mode buffers."
+  :type 'hook
+  :group 'gnus-topic)
 
-(defvar gnus-topic-line-format "%i[ %(%{%n%}%) -- %A ]%v\n"
+(defcustom gnus-topic-line-format "%i[ %(%{%n%}%) -- %A ]%v\n"
   "Format of topic lines.
 It works along the same lines as a normal formatting string,
 with some simple extensions.
@@ -46,22 +57,31 @@ with some simple extensions.
 %g  Number of groups in the topic.
 %a  Number of unread articles in the groups in the topic.
 %A  Number of unread articles in the groups in the topic and its subtopics.
-")
+"
+  :type 'string
+  :group 'gnus-topic)
 
-(defvar gnus-topic-unique t
-  "*If non-nil, each group will only belong to one topic.")
+(defcustom gnus-topic-indent-level 2
+  "*How much each subtopic should be indented."
+  :type 'integer
+  :group 'gnus-topic)
 
-(defvar gnus-topic-indent-level 2
-  "*How much each subtopic should be indented.")
+(defcustom gnus-topic-display-empty-topics t
+  "*If non-nil, display the topic lines even of topics that have no unread articles."
+  :type 'boolean
+  :group 'gnus-topic)
 
 ;; Internal variables.
 
 (defvar gnus-topic-active-topology nil)
 (defvar gnus-topic-active-alist nil)
+(defvar gnus-topic-unreads nil)
+
+(defvar gnus-topology-checked-p nil
+  "Whether the topology has been checked in this session.")
 
 (defvar gnus-topic-killed-topics nil)
 (defvar gnus-topic-inhibit-change-level nil)
-(defvar gnus-topic-tallied-groups nil)
 
 (defconst gnus-topic-line-format-alist
   `((?n name ?s)
@@ -74,166 +94,400 @@ with some simple extensions.
 
 (defvar gnus-topic-line-format-spec nil)
 
-;; Functions.
+;;; Utility functions
 
 (defun gnus-group-topic-name ()
   "The name of the topic on the current line."
-  (let ((group (get-text-property (gnus-point-at-bol) 'gnus-topic)))
-    (and group (symbol-name group))))
+  (let ((topic (get-text-property (gnus-point-at-bol) 'gnus-topic)))
+    (and topic (symbol-name topic))))
 
 (defun gnus-group-topic-level ()
   "The level of the topic on the current line."
   (get-text-property (gnus-point-at-bol) 'gnus-topic-level))
 
-(defun gnus-topic-init-alist ()
-  "Initialize the topic structures."
-  (setq gnus-topic-topology
-	(cons (list "Gnus" 'visible)
-	      (mapcar (lambda (topic)
-			(list (list (car topic) 'visible)))
-		      '(("misc")))))
-  (setq gnus-topic-alist
-	(list (cons "misc"
-		    (mapcar (lambda (info) (gnus-info-group info))
-			    (cdr gnus-newsrc-alist)))
-	      (list "Gnus")))
-  (gnus-topic-enter-dribble))
+(defun gnus-group-topic-unread ()
+  "The number of unread articles in topic on the current line."
+  (get-text-property (gnus-point-at-bol) 'gnus-topic-unread))
+
+(defun gnus-topic-unread (topic)
+  "Return the number of unread articles in TOPIC."
+  (or (cdr (assoc topic gnus-topic-unreads))
+      0))
+
+(defun gnus-group-topic-p ()
+  "Return non-nil if the current line is a topic."
+  (gnus-group-topic-name))
+
+(defun gnus-topic-visible-p ()
+  "Return non-nil if the current topic is visible."
+  (get-text-property (gnus-point-at-bol) 'gnus-topic-visible))
+
+(defun gnus-topic-articles-in-topic (entries)
+  (let ((total 0)
+	number)
+    (while entries
+      (when (numberp (setq number (car (pop entries))))
+	(incf total number)))
+    total))
+
+(defun gnus-group-topic (group)
+  "Return the topic GROUP is a member of."
+  (let ((alist gnus-topic-alist)
+	out)
+    (while alist
+      (when (member group (cdar alist))
+	(setq out (caar alist)
+	      alist nil))
+      (setq alist (cdr alist)))
+    out))
+
+(defun gnus-group-parent-topic (group)
+  "Return the topic GROUP is member of by looking at the group buffer."
+  (save-excursion
+    (set-buffer gnus-group-buffer)
+    (if (gnus-group-goto-group group)
+	(gnus-current-topic)
+      (gnus-group-topic group))))
+
+(defun gnus-topic-goto-topic (topic)
+  (when topic
+    (gnus-goto-char (text-property-any (point-min) (point-max)
+				       'gnus-topic (intern topic)))))
+
+(defun gnus-topic-jump-to-topic (topic)
+  "Go to TOPIC."
+  (interactive
+   (list (completing-read "Go to topic: "
+			  (mapcar 'list (gnus-topic-list))
+			  nil t)))
+  (dolist (topic (gnus-current-topics topic))
+    (gnus-topic-fold t))
+  (gnus-topic-goto-topic topic))
+  
+(defun gnus-current-topic ()
+  "Return the name of the current topic."
+  (let ((result
+	 (or (get-text-property (point) 'gnus-topic)
+	     (save-excursion
+	       (and (gnus-goto-char (previous-single-property-change
+				     (point) 'gnus-topic))
+		    (get-text-property (max (1- (point)) (point-min))
+				       'gnus-topic))))))
+    (when result
+      (symbol-name result))))
+
+(defun gnus-current-topics (&optional topic)
+  "Return a list of all current topics, lowest in hierarchy first.
+If TOPIC, start with that topic."
+  (let ((topic (or topic (gnus-current-topic)))
+	topics)
+    (while topic
+      (push topic topics)
+      (setq topic (gnus-topic-parent-topic topic)))
+    (nreverse topics)))
+
+(defun gnus-group-active-topic-p ()
+  "Say whether the current topic comes from the active topics."
+  (save-excursion
+    (beginning-of-line)
+    (get-text-property (point) 'gnus-active)))
+
+(defun gnus-topic-find-groups (topic &optional level all lowest)
+  "Return entries for all visible groups in TOPIC."
+  (let ((groups (cdr (assoc topic gnus-topic-alist)))
+        info clevel unread group params visible-groups entry active)
+    (setq lowest (or lowest 1))
+    (setq level (or level gnus-level-unsubscribed))
+    ;; We go through the newsrc to look for matches.
+    (while groups
+      (when (setq group (pop groups))
+	(setq entry (gnus-gethash group gnus-newsrc-hashtb)
+	      info (nth 2 entry)
+	      params (gnus-info-params info)
+	      active (gnus-active group)
+	      unread (or (car entry)
+			 (and (not (equal group "dummy.group"))
+			      active
+			      (- (1+ (cdr active)) (car active))))
+	      clevel (or (gnus-info-level info)
+			 (if (member group gnus-zombie-list)
+			     gnus-level-zombie gnus-level-killed))))
+      (and
+       info				; nil means that the group is dead.
+       (<= clevel level)
+       (>= clevel lowest)		; Is inside the level we want.
+       (or all
+	   (if (or (eq unread t)
+		   (eq unread nil))
+	       gnus-group-list-inactive-groups
+	     (> unread 0))
+	   (and gnus-list-groups-with-ticked-articles
+		(cdr (assq 'tick (gnus-info-marks info))))
+	   ;; Has right readedness.
+	   ;; Check for permanent visibility.
+	   (and gnus-permanently-visible-groups
+		(string-match gnus-permanently-visible-groups group))
+	   (memq 'visible params)
+	   (cdr (assq 'visible params)))
+       ;; Add this group to the list of visible groups.
+       (push (or entry group) visible-groups)))
+    (nreverse visible-groups)))
+
+(defun gnus-topic-previous-topic (topic)
+  "Return the previous topic on the same level as TOPIC."
+  (let ((top (cddr (gnus-topic-find-topology
+		    (gnus-topic-parent-topic topic)))))
+    (unless (equal topic (caaar top))
+      (while (and top (not (equal (caaadr top) topic)))
+	(setq top (cdr top)))
+      (caaar top))))
+
+(defun gnus-topic-parent-topic (topic &optional topology)
+  "Return the parent of TOPIC."
+  (unless topology
+    (setq topology gnus-topic-topology))
+  (let ((parent (car (pop topology)))
+	result found)
+    (while (and topology
+		(not (setq found (equal (caaar topology) topic)))
+		(not (setq result (gnus-topic-parent-topic
+				   topic (car topology)))))
+      (setq topology (cdr topology)))
+    (or result (and found parent))))
+
+(defun gnus-topic-next-topic (topic &optional previous)
+  "Return the next sibling of TOPIC."
+  (let ((parentt (cddr (gnus-topic-find-topology
+			(gnus-topic-parent-topic topic))))
+	prev)
+    (while (and parentt
+		(not (equal (caaar parentt) topic)))
+      (setq prev (caaar parentt)
+	    parentt (cdr parentt)))
+    (if previous
+	prev
+      (caaadr parentt))))
+
+(defun gnus-topic-forward-topic (num)
+  "Go to the next topic on the same level as the current one."
+  (let* ((topic (gnus-current-topic))
+	 (way (if (< num 0) 'gnus-topic-previous-topic
+		'gnus-topic-next-topic))
+	 (num (abs num)))
+    (while (and (not (zerop num))
+		(setq topic (funcall way topic)))
+      (when (gnus-topic-goto-topic topic)
+	(decf num)))
+    (unless (zerop num)
+      (goto-char (point-max)))
+    num))
 
-(defun gnus-group-prepare-topics (level &optional all lowest regexp list-topic topic-level)
-  "List all newsgroups with unread articles of level LEVEL or lower, and
-use the `gnus-group-topics' to sort the groups.
+(defun gnus-topic-find-topology (topic &optional topology level remove)
+  "Return the topology of TOPIC."
+  (unless topology
+    (setq topology gnus-topic-topology)
+    (setq level 0))
+  (let ((top topology)
+	result)
+    (if (equal (caar topology) topic)
+	(progn
+	  (when remove
+	    (delq topology remove))
+	  (cons level topology))
+      (setq topology (cdr topology))
+      (while (and topology
+		  (not (setq result (gnus-topic-find-topology
+				     topic (car topology) (1+ level)
+				     (and remove top)))))
+	(setq topology (cdr topology)))
+      result)))
+
+(defvar gnus-tmp-topics nil)
+(defun gnus-topic-list (&optional topology)
+  "Return a list of all topics in the topology."
+  (unless topology
+    (setq topology gnus-topic-topology
+	  gnus-tmp-topics nil))
+  (push (caar topology) gnus-tmp-topics)
+  (mapcar 'gnus-topic-list (cdr topology))
+  gnus-tmp-topics)
+
+;;; Topic parameter jazz
+
+(defun gnus-topic-parameters (topic)
+  "Return the parameters for TOPIC."
+  (let ((top (gnus-topic-find-topology topic)))
+    (when top
+      (nth 3 (cadr top)))))
+
+(defun gnus-topic-set-parameters (topic parameters)
+  "Set the topic parameters of TOPIC to PARAMETERS."
+  (let ((top (gnus-topic-find-topology topic)))
+    (unless top
+      (error "No such topic: %s" topic))
+    ;; We may have to extend if there is no parameters here
+    ;; to begin with.
+    (unless (nthcdr 2 (cadr top))
+      (nconc (cadr top) (list nil)))
+    (unless (nthcdr 3 (cadr top))
+      (nconc (cadr top) (list nil)))
+    (setcar (nthcdr 3 (cadr top)) parameters)
+    (gnus-dribble-enter
+     (format "(gnus-topic-set-parameters %S '%S)" topic parameters))))
+
+(defun gnus-group-topic-parameters (group)
+  "Compute the group parameters for GROUP taking into account inheritance from topics."
+  (let ((params-list (copy-sequence (gnus-group-get-parameter group))))
+    (save-excursion
+      (gnus-group-goto-group group)
+      (nconc params-list
+	     (gnus-topic-hierarchical-parameters (gnus-current-topic))))))
+
+(defun gnus-topic-hierarchical-parameters (topic)
+  "Return a topic list computed for TOPIC."
+  (let ((topics (gnus-current-topics topic))
+	params-list param out params)
+    (while topics
+      (push (gnus-topic-parameters (pop topics)) params-list))
+    ;; We probably have lots of nil elements here, so
+    ;; we remove them.  Probably faster than doing this "properly".
+    (setq params-list (delq nil params-list))
+    ;; Now we have all the parameters, so we go through them
+    ;; and do inheritance in the obvious way.
+    (while (setq params (pop params-list))
+      (while (setq param (pop params))
+	(when (atom param)
+	  (setq param (cons param t)))
+	;; Override any old versions of this param.
+	(gnus-pull (car param) out)
+	(push param out)))
+    ;; Return the resulting parameter list.
+    out))
+
+;;; General utility functions
+
+(defun gnus-topic-enter-dribble ()
+  (gnus-dribble-enter
+   (format "(setq gnus-topic-topology '%S)" gnus-topic-topology)))
+
+;;; Generating group buffers
+
+(defun gnus-group-prepare-topics (level &optional all lowest
+					regexp list-topic topic-level)
+  "List all newsgroups with unread articles of level LEVEL or lower.
+Use the `gnus-group-topics' to sort the groups.
 If ALL is non-nil, list groups that have no unread articles.
 If LOWEST is non-nil, list all newsgroups of level LOWEST or higher."
   (set-buffer gnus-group-buffer)
   (let ((buffer-read-only nil)
         (lowest (or lowest 1)))
 
-    (setq gnus-topic-tallied-groups nil)
-
-    (unless gnus-topic-alist
+    (when (or (not gnus-topic-alist)
+	      (not gnus-topology-checked-p))
       (gnus-topic-check-topology))
 
-    (unless list-topic 
+    (unless list-topic
       (erase-buffer))
-    
+
     ;; List dead groups?
-    (when (and (>= level gnus-level-zombie) (<= lowest gnus-level-zombie))
-      (gnus-group-prepare-flat-list-dead 
-       (setq gnus-zombie-list (sort gnus-zombie-list 'string<)) 
+    (when (and (>= level gnus-level-zombie)
+	       (<= lowest gnus-level-zombie))
+      (gnus-group-prepare-flat-list-dead
+       (setq gnus-zombie-list (sort gnus-zombie-list 'string<))
        gnus-level-zombie ?Z
        regexp))
-    
+
     (when (and (>= level gnus-level-killed) (<= lowest gnus-level-killed))
-      (gnus-group-prepare-flat-list-dead 
+      (gnus-group-prepare-flat-list-dead
        (setq gnus-killed-list (sort gnus-killed-list 'string<))
        gnus-level-killed ?K
        regexp))
 
     ;; Use topics.
-    (when (< lowest gnus-level-zombie)
-      (if list-topic
-	  (let ((top (gnus-topic-find-topology list-topic)))
-	    (gnus-topic-prepare-topic (cdr top) (car top)
-				      (or topic-level level) all))
-	(gnus-topic-prepare-topic gnus-topic-topology 0
-				  (or topic-level level) all))))
-
-  (gnus-group-set-mode-line)
-  (setq gnus-group-list-mode (cons level all))
-  (run-hooks 'gnus-group-prepare-hook))
-
-(defun gnus-topic-prepare-topic (topic level &optional list-level all silent)
+    (prog1
+	(when (< lowest gnus-level-zombie)
+	  (if list-topic
+	      (let ((top (gnus-topic-find-topology list-topic)))
+		(gnus-topic-prepare-topic (cdr top) (car top)
+					  (or topic-level level) all
+					  nil lowest))
+	    (gnus-topic-prepare-topic gnus-topic-topology 0
+				      (or topic-level level) all
+				      nil lowest)))
+
+      (gnus-group-set-mode-line)
+      (setq gnus-group-list-mode (cons level all))
+      (gnus-run-hooks 'gnus-group-prepare-hook))))
+
+(defun gnus-topic-prepare-topic (topicl level &optional list-level all silent
+					lowest)
   "Insert TOPIC into the group buffer.
 If SILENT, don't insert anything.  Return the number of unread
 articles in the topic and its subtopics."
-  (let* ((type (pop topic))
-	 (entries (gnus-topic-find-groups (car type) list-level all))
+  (let* ((type (pop topicl))
+	 (entries (gnus-topic-find-groups
+		   (car type) list-level
+		   (or all
+		       (cdr (assq 'visible
+				  (gnus-topic-hierarchical-parameters
+				   (car type)))))
+		   lowest))
 	 (visiblep (and (eq (nth 1 type) 'visible) (not silent)))
-	 (gnus-group-indentation 
+	 (gnus-group-indentation
 	  (make-string (* gnus-topic-indent-level level) ? ))
 	 (beg (progn (beginning-of-line) (point)))
-	 (topic (reverse topic))
+	 (topicl (reverse topicl))
 	 (all-entries entries)
+	 (point-max (point-max))
 	 (unread 0)
-	 info entry end active)
+	 (topic (car type))
+	 info entry end active tick)
     ;; Insert any sub-topics.
-    (while topic
+    (while topicl
       (incf unread
-	    (gnus-topic-prepare-topic 
-	     (pop topic) (1+ level) list-level all
-	     (not visiblep))))
+	    (gnus-topic-prepare-topic
+	     (pop topicl) (1+ level) list-level all
+	     (not visiblep) lowest)))
     (setq end (point))
     (goto-char beg)
     ;; Insert all the groups that belong in this topic.
     (while (setq entry (pop entries))
-      (when visiblep 
+      (when visiblep
 	(if (stringp entry)
 	    ;; Dead groups.
 	    (gnus-group-insert-group-line
-	     entry (if (member entry gnus-zombie-list) 8 9)
+	     entry (if (member entry gnus-zombie-list)
+		       gnus-level-zombie gnus-level-killed)
 	     nil (- (1+ (cdr (setq active (gnus-active entry))))
-		    (car active)) nil)
+		    (car active))
+	     nil)
 	  ;; Living groups.
 	  (when (setq info (nth 2 entry))
-	    (gnus-group-insert-group-line 
+	    (gnus-group-insert-group-line
 	     (gnus-info-group info)
-	     (gnus-info-level info) (gnus-info-marks info) 
+	     (gnus-info-level info) (gnus-info-marks info)
 	     (car entry) (gnus-info-method info)))))
       (when (and (listp entry)
-		 (numberp (car entry))
-		 (not (member (gnus-info-group (setq info (nth 2 entry)))
-			      gnus-topic-tallied-groups)))
-	(push (gnus-info-group info) gnus-topic-tallied-groups)
-	(incf unread (car entry))))
+		 (numberp (car entry)))
+	(incf unread (car entry)))
+      (when (listp entry)
+	(setq tick t)))
     (goto-char beg)
     ;; Insert the topic line.
-    (unless silent
+    (when (and (not silent)
+	       (or gnus-topic-display-empty-topics ;We want empty topics
+		   (not (zerop unread))	;Non-empty
+		   tick			;Ticked articles
+		   (/= point-max (point-max)))) ;Unactivated groups
       (gnus-extent-start-open (point))
-      (gnus-topic-insert-topic-line 
+      (gnus-topic-insert-topic-line
        (car type) visiblep
        (not (eq (nth 2 type) 'hidden))
        level all-entries unread))
+    (gnus-topic-update-unreads (car type) unread)
     (goto-char end)
     unread))
 
-(defun gnus-topic-find-groups (topic &optional level all)
-  "Return entries for all visible groups in TOPIC."
-  (let ((groups (cdr (assoc topic gnus-topic-alist)))
-        info clevel unread group lowest params visible-groups entry active)
-    (setq lowest (or lowest 1))
-    (setq level (or level 7))
-    ;; We go through the newsrc to look for matches.
-    (while groups
-      (setq entry (gnus-gethash (setq group (pop groups)) gnus-newsrc-hashtb)
-	    info (nth 2 entry)
-	    params (gnus-info-params info)
-	    active (gnus-active group)
-            unread (or (car entry)
-		       (and (not (equal group "dummy.group"))
-			    active
-			    (- (1+ (cdr active)) (car active))))
-	    clevel (or (gnus-info-level info)
-		       (if (member group gnus-zombie-list) 8 9)))
-      (and 
-       unread				; nil means that the group is dead.
-       (<= clevel level) 
-       (>= clevel lowest)		; Is inside the level we want.
-       (or all
-	   (if (eq unread t)
-	       gnus-group-list-inactive-groups
-	     (> unread 0))
-	   (and gnus-list-groups-with-ticked-articles
-		(cdr (assq 'tick (gnus-info-marks info))))
-					; Has right readedness.
-	   ;; Check for permanent visibility.
-	   (and gnus-permanently-visible-groups
-		(string-match gnus-permanently-visible-groups group))
-	   (memq 'visible params)
-	   (cdr (assq 'visible params)))
-       ;; Add this group to the list of visible groups.
-       (push (or entry group) visible-groups)))
-    (nreverse visible-groups)))
-
 (defun gnus-topic-remove-topic (&optional insert total-remove hide in-level)
   "Remove the current topic."
   (let ((topic (gnus-group-topic-name))
@@ -244,23 +498,29 @@ articles in the topic and its subtopics."
       (while (and (zerop (forward-line 1))
 		  (> (or (gnus-group-topic-level) (1+ level)) level)))
       (delete-region beg (point))
-      (setcar (cdadr (gnus-topic-find-topology topic))
-	      (if insert 'visible 'invisible))
-      (when hide
-	(setcdr (cdadr (gnus-topic-find-topology topic))
-		(list hide)))
-      (unless total-remove
+      ;; Do the change in this rather odd manner because it has been
+      ;; reported that some topics share parts of some lists, for some
+      ;; reason.  I have been unable to determine why this is the
+      ;; case, but this hack seems to take care of things.
+      (let ((data (cadr (gnus-topic-find-topology topic))))
+	(setcdr data
+		(list (if insert 'visible 'invisible)
+		      hide
+		      (cadddr data))))
+      (if total-remove
+	  (setq gnus-topic-alist
+		(delq (assoc topic gnus-topic-alist) gnus-topic-alist))
 	(gnus-topic-insert-topic topic in-level)))))
 
 (defun gnus-topic-insert-topic (topic &optional level)
   "Insert TOPIC."
-  (gnus-group-prepare-topics 
+  (gnus-group-prepare-topics
    (car gnus-group-list-mode) (cdr gnus-group-list-mode)
    nil nil topic level))
-  
-(defun gnus-topic-fold (&optional insert)
+
+(defun gnus-topic-fold (&optional insert topic)
   "Remove/insert the current topic."
-  (let ((topic (gnus-group-topic-name))) 
+  (let ((topic (or topic (gnus-group-topic-name))))
     (when topic
       (save-excursion
 	(if (not (gnus-group-active-topic-p))
@@ -270,76 +530,170 @@ articles in the topic and its subtopics."
 		(gnus-topic-alist gnus-topic-active-alist)
 		(gnus-group-list-mode (cons 5 t)))
 	    (gnus-topic-remove-topic
-	     (or insert (not (gnus-topic-visible-p))) nil nil 9)))))))
+	     (or insert (not (gnus-topic-visible-p))) nil nil 9)
+	    (gnus-topic-enter-dribble)))))))
 
-(defun gnus-group-topic-p ()
-  "Return non-nil if the current line is a topic."
-  (gnus-group-topic-name))
-
-(defun gnus-topic-visible-p ()
-  "Return non-nil if the current topic is visible."
-  (get-text-property (gnus-point-at-bol) 'gnus-topic-visible))
-
-(defun gnus-topic-insert-topic-line (name visiblep shownp level entries 
+(defun gnus-topic-insert-topic-line (name visiblep shownp level entries
 					  &optional unread)
   (let* ((visible (if visiblep "" "..."))
 	 (indentation (make-string (* gnus-topic-indent-level level) ? ))
 	 (total-number-of-articles unread)
 	 (number-of-groups (length entries))
-	 (active-topic (eq gnus-topic-alist gnus-topic-active-alist)))
+	 (active-topic (eq gnus-topic-alist gnus-topic-active-alist))
+	 gnus-tmp-header)
+    (gnus-topic-update-unreads name unread)
     (beginning-of-line)
     ;; Insert the text.
-    (add-text-properties 
-     (point)
-     (prog1 (1+ (point)) 
-       (eval gnus-topic-line-format-spec)
-       (gnus-topic-remove-excess-properties))
-     (list 'gnus-topic (intern name)
-	   'gnus-topic-level level
-	   'gnus-active active-topic
-	   'gnus-topic-visible visiblep))))
+    (if shownp
+	(gnus-add-text-properties
+	 (point)
+	 (prog1 (1+ (point))
+	   (eval gnus-topic-line-format-spec))
+	 (list 'gnus-topic (intern name)
+	       'gnus-topic-level level
+	       'gnus-topic-unread unread
+	       'gnus-active active-topic
+	       'gnus-topic-visible visiblep)))))
+
+(defun gnus-topic-update-unreads (topic unreads)
+  (setq gnus-topic-unreads (delq (assoc topic gnus-topic-unreads)
+				 gnus-topic-unreads))
+  (push (cons topic unreads) gnus-topic-unreads))
+
+(defun gnus-topic-update-topics-containing-group (group)
+  "Update all topics that have GROUP as a member."
+  (when (and (eq major-mode 'gnus-group-mode)
+	     gnus-topic-mode)
+    (save-excursion
+      (let ((alist gnus-topic-alist))
+	;; This is probably not entirely correct.  If a topic
+	;; isn't shown, then it's not updated.  But the updating
+	;; should be performed in any case, since the topic's
+	;; parent should be updated.  Pfft.
+	(while alist
+	  (when (and (member group (cdar alist))
+		     (gnus-topic-goto-topic (caar alist)))
+	    (gnus-topic-update-topic-line (caar alist)))
+	  (pop alist))))))
 
-(defun gnus-topic-previous-topic (topic)
-  "Return the previous topic on the same level as TOPIC."
-  (let ((top (cddr (gnus-topic-find-topology
-			(gnus-topic-parent-topic topic)))))
-    (unless (equal topic (caaar top))
-      (while (and top (not (equal (caaadr top) topic)))
-	(setq top (cdr top)))
-      (caaar top))))
+(defun gnus-topic-update-topic ()
+  "Update all parent topics to the current group."
+  (when (and (eq major-mode 'gnus-group-mode)
+	     gnus-topic-mode)
+    (let ((group (gnus-group-group-name))
+          (m (point-marker))
+	  (buffer-read-only nil))
+      (when (and group
+		 (gnus-get-info group)
+		 (gnus-topic-goto-topic (gnus-current-topic)))
+	(gnus-topic-update-topic-line (gnus-group-topic-name))
+	(goto-char m)
+	(set-marker m nil)
+	(gnus-group-position-point)))))
 
-(defun gnus-topic-parent-topic (topic &optional topology)
-  "Return the parent of TOPIC."
-  (unless topology
-    (setq topology gnus-topic-topology))
-  (let ((parent (car (pop topology)))
-	result found)
-    (while (and topology
-		(not (setq found (equal (caaar topology) topic)))
-		(not (setq result (gnus-topic-parent-topic topic 
-							   (car topology)))))
-      (setq topology (cdr topology)))
-    (or result (and found parent))))
+(defun gnus-topic-goto-missing-group (group)
+  "Place point where GROUP is supposed to be inserted."
+  (let* ((topic (gnus-group-topic group))
+	 (groups (cdr (assoc topic gnus-topic-alist)))
+	 (g (cdr (member group groups)))
+	 (unfound t)
+	 entry)
+    ;; Try to jump to a visible group.
+    (while (and g (not (gnus-group-goto-group (car g) t)))
+      (pop g))
+    ;; It wasn't visible, so we try to see where to insert it.
+    (when (not g)
+      (setq g (cdr (member group (reverse groups))))
+      (while (and g unfound)
+	(when (gnus-group-goto-group (pop g) t)
+	  (forward-line 1)
+	  (setq unfound nil)))
+      (when (and unfound
+		 topic
+		 (not (gnus-topic-goto-missing-topic topic)))
+	(let* ((top (gnus-topic-find-topology topic))
+	       (children (cddr top))
+	       (type (cadr top))
+	       (unread 0)
+	       (entries (gnus-topic-find-groups
+			 (car type) (car gnus-group-list-mode)
+			 (cdr gnus-group-list-mode))))
+	  (while children
+	    (incf unread (gnus-topic-unread (caar (pop children)))))
+	  (while (setq entry (pop entries))
+	    (when (numberp (car entry))
+	      (incf unread (car entry))))
+	  (gnus-topic-insert-topic-line
+	   topic t t (car (gnus-topic-find-topology topic)) nil unread))))))
+
+(defun gnus-topic-goto-missing-topic (topic)
+  (if (gnus-topic-goto-topic topic)
+      (forward-line 1)
+    ;; Topic not displayed.
+    (let* ((top (gnus-topic-find-topology
+		 (gnus-topic-parent-topic topic)))
+	   (tp (reverse (cddr top))))
+      (if (not top)
+	  (gnus-topic-insert-topic-line
+	   topic t t (car (gnus-topic-find-topology topic)) nil 0)
+	(while (not (equal (caaar tp) topic))
+	  (setq tp (cdr tp)))
+	(pop tp)
+	(while (and tp
+		    (not (gnus-topic-goto-topic (caaar tp))))
+	  (pop tp))
+	(if tp
+	    (gnus-topic-forward-topic 1)
+	  (gnus-topic-goto-missing-topic (caadr top)))))
+    nil))
+
+(defun gnus-topic-update-topic-line (topic-name &optional reads)
+  (let* ((top (gnus-topic-find-topology topic-name))
+	 (type (cadr top))
+	 (children (cddr top))
+	 (entries (gnus-topic-find-groups
+		   (car type) (car gnus-group-list-mode)
+		   (cdr gnus-group-list-mode)))
+	 (parent (gnus-topic-parent-topic topic-name))
+	 (all-entries entries)
+	 (unread 0)
+	 old-unread entry new-unread)
+    (when (gnus-topic-goto-topic (car type))
+      ;; Tally all the groups that belong in this topic.
+      (if reads
+	  (setq unread (- (gnus-group-topic-unread) reads))
+	(while children
+	  (incf unread (gnus-topic-unread (caar (pop children)))))
+	(while (setq entry (pop entries))
+	  (when (numberp (car entry))
+	    (incf unread (car entry)))))
+      (setq old-unread (gnus-group-topic-unread))
+      ;; Insert the topic line.
+      (gnus-topic-insert-topic-line
+       (car type) (gnus-topic-visible-p)
+       (not (eq (nth 2 type) 'hidden))
+       (gnus-group-topic-level) all-entries unread)
+      (gnus-delete-line)
+      (forward-line -1)
+      (setq new-unread (gnus-group-topic-unread)))
+    (when parent
+      (forward-line -1)
+      (gnus-topic-update-topic-line
+       parent
+       (- (or old-unread 0) (or new-unread 0))))
+    unread))
 
-(defun gnus-topic-find-topology (topic &optional topology level remove)
-  "Return the topology of TOPIC."
-  (unless topology
-    (setq topology gnus-topic-topology)
-    (setq level 0))
-  (let ((top topology)
-	result)
-    (if (equal (caar topology) topic)
-	(progn
-	  (when remove
-	    (delq topology remove))
-	  (cons level topology))
-      (setq topology (cdr topology))
-      (while (and topology
-		  (not (setq result (gnus-topic-find-topology
-				     topic (car topology) (1+ level)
-				     (and remove top)))))
-	(setq topology (cdr topology)))
-      result)))
+(defun gnus-topic-group-indentation ()
+  (make-string
+   (* gnus-topic-indent-level
+      (or (save-excursion
+	    (forward-line -1)
+	    (gnus-topic-goto-topic (gnus-current-topic))
+	    (gnus-group-topic-level))
+	  0))
+   ? ))
+
+;;; Initialization
 
 (gnus-add-shutdown 'gnus-topic-close 'gnus)
 
@@ -347,14 +701,17 @@ articles in the topic and its subtopics."
   (setq gnus-topic-active-topology nil
 	gnus-topic-active-alist nil
 	gnus-topic-killed-topics nil
-	gnus-topic-tallied-groups nil))
+	gnus-topology-checked-p nil))
 
-(defun gnus-topic-check-topology ()  
+(defun gnus-topic-check-topology ()
   ;; The first time we set the topology to whatever we have
   ;; gotten here, which can be rather random.
   (unless gnus-topic-alist
     (gnus-topic-init-alist))
 
+  (setq gnus-topology-checked-p t)
+  ;; Go through the topic alist and make sure that all topics
+  ;; are in the topic topology.
   (let ((topics (gnus-topic-list))
 	(alist gnus-topic-alist)
 	changed)
@@ -365,131 +722,162 @@ articles in the topic and its subtopics."
 	(setq changed t))
       (setq alist (cdr alist)))
     (when changed
-      (gnus-topic-enter-dribble)))
+      (gnus-topic-enter-dribble))
+    ;; Conversely, go through the topology and make sure that all
+    ;; topologies have alists.
+    (while topics
+      (unless (assoc (car topics) gnus-topic-alist)
+	(push (list (car topics)) gnus-topic-alist))
+      (pop topics)))
+  ;; Go through all living groups and make sure that
+  ;; they belong to some topic.
   (let* ((tgroups (apply 'append (mapcar (lambda (entry) (cdr entry))
 					 gnus-topic-alist)))
-	 (entry (assoc (caar gnus-topic-topology) gnus-topic-alist))
-	 (newsrc gnus-newsrc-alist)
+	 (entry (last (assoc (caar gnus-topic-topology) gnus-topic-alist)))
+	 (newsrc (cdr gnus-newsrc-alist))
 	 group)
     (while newsrc
       (unless (member (setq group (gnus-info-group (pop newsrc))) tgroups)
-	(setcdr entry (cons group (cdr entry)))))))
-
-(defvar gnus-tmp-topics nil)
-(defun gnus-topic-list (&optional topology)
-  (unless topology
-    (setq topology gnus-topic-topology 
-	  gnus-tmp-topics nil))
-  (push (caar topology) gnus-tmp-topics)
-  (mapcar 'gnus-topic-list (cdr topology))
-  gnus-tmp-topics)
-
-(defun gnus-topic-enter-dribble ()
-  (gnus-dribble-enter
-   (format "(setq gnus-topic-topology '%S)" gnus-topic-topology)))
-
-(defun gnus-topic-articles-in-topic (entries)
-  (let ((total 0)
-	number)
-    (while entries
-      (when (numberp (setq number (car (pop entries))))
-	(incf total number)))
-    total))
-
-(defun gnus-group-parent-topic ()
-  "Return the topic the current group belongs in."
-  (let ((group (gnus-group-group-name)))
-    (if group
-	(gnus-group-topic group)
-      (gnus-group-topic-name))))
-
-(defun gnus-group-topic (group)
-  "Return the topic GROUP is a member of."
+	(setcdr entry (list group))
+	(setq entry (cdr entry)))))
+  ;; Go through all topics and make sure they contain only living groups.
   (let ((alist gnus-topic-alist)
-	out)
-    (while alist
-      (when (member group (cdar alist))
-	(setq out (caar alist)
-	      alist nil))
-      (setq alist (cdr alist)))
-    out))
+	topic)
+    (while (setq topic (pop alist))
+      (while (cdr topic)
+	(if (and (cadr topic)
+		 (gnus-gethash (cadr topic) gnus-newsrc-hashtb))
+	    (setq topic (cdr topic))
+	  (setcdr topic (cddr topic)))))))
 
-(defun gnus-topic-goto-topic (topic)
-  (when topic
-    (gnus-goto-char (text-property-any (point-min) (point-max)
-				       'gnus-topic (intern topic)))))
-  
-(defun gnus-topic-update-topic ()
-  "Update all parent topics to the current group."
-  (when (and (eq major-mode 'gnus-group-mode)
-	     gnus-topic-mode)
-    (let ((group (gnus-group-group-name)))
-      (when (and group (gnus-get-info group))
-	(gnus-topic-goto-topic (gnus-group-parent-topic))
-	(gnus-topic-update-topic-line)
-	(gnus-group-goto-group group)
-	(gnus-group-position-point)))))
+(defun gnus-topic-init-alist ()
+  "Initialize the topic structures."
+  (setq gnus-topic-topology
+	(cons (list "Gnus" 'visible)
+	      (mapcar (lambda (topic)
+			(list (list (car topic) 'visible)))
+		      '(("misc")))))
+  (setq gnus-topic-alist
+	(list (cons "misc"
+		    (mapcar (lambda (info) (gnus-info-group info))
+			    (cdr gnus-newsrc-alist)))
+	      (list "Gnus")))
+  (gnus-topic-enter-dribble))
 
-(defun gnus-topic-goto-missing-group (group) 
-  "Place point where GROUP is supposed to be inserted."
-  (let* ((topic (gnus-group-topic group))
-	 (groups (cdr (assoc topic gnus-topic-alist)))
-	 (g (cdr (member group groups)))
-	 (unfound t))
-    (while (and g unfound)
-      (when (gnus-group-goto-group (pop g))
-	(beginning-of-line)
-	(setq unfound nil)))
-    (when unfound
-      (setq g (cdr (member group (reverse groups))))
-      (while (and g unfound)
-	(when (gnus-group-goto-group (pop g))
-	  (forward-line 1)
-	  (setq unfound nil)))
-      (when unfound
-	(gnus-topic-goto-topic topic)
-	(forward-line 1)))))
+;;; Maintenance
+
+(defun gnus-topic-clean-alist ()
+  "Remove bogus groups from the topic alist."
+  (let ((topic-alist gnus-topic-alist)
+	result topic)
+    (unless gnus-killed-hashtb
+      (gnus-make-hashtable-from-killed))
+    (while (setq topic (pop topic-alist))
+      (let ((topic-name (pop topic))
+	    group filtered-topic)
+	(while (setq group (pop topic))
+	  (when (and (or (gnus-gethash group gnus-active-hashtb)
+			 (gnus-info-method (gnus-get-info group)))
+		     (not (gnus-gethash group gnus-killed-hashtb)))
+	    (push group filtered-topic)))
+	(push (cons topic-name (nreverse filtered-topic)) result)))
+    (setq gnus-topic-alist (nreverse result))))
+
+(defun gnus-topic-change-level (group level oldlevel &optional previous)
+  "Run when changing levels to enter/remove groups from topics."
+  (save-excursion
+    (set-buffer gnus-group-buffer)
+    (let ((buffer-read-only nil))
+      (unless gnus-topic-inhibit-change-level
+	(gnus-group-goto-group (or (car (nth 2 previous)) group))
+	(when (and gnus-topic-mode
+		   gnus-topic-alist
+		   (not gnus-topic-inhibit-change-level))
+	  ;; Remove the group from the topics.
+	  (if (and (< oldlevel gnus-level-zombie)
+		   (>= level gnus-level-zombie))
+	      (let ((alist gnus-topic-alist))
+		(while (gnus-group-goto-group group)
+		  (gnus-delete-line))
+		(while alist
+		  (when (member group (car alist))
+		    (setcdr (car alist) (delete group (cdar alist))))
+		  (pop alist)))
+	    ;; If the group is subscribed we enter it into the topics.
+	    (when (and (< level gnus-level-zombie)
+		       (>= oldlevel gnus-level-zombie))
+	      (let* ((prev (gnus-group-group-name))
+		     (gnus-topic-inhibit-change-level t)
+		     (gnus-group-indentation
+		      (make-string
+		       (* gnus-topic-indent-level
+			  (or (save-excursion
+				(gnus-topic-goto-topic (gnus-current-topic))
+				(gnus-group-topic-level))
+			      0))
+		       ? ))
+		     (yanked (list group))
+		     alist talist end)
+		;; Then we enter the yanked groups into the topics they belong
+		;; to.
+		(when (setq alist (assoc (save-excursion
+					   (forward-line -1)
+					   (or
+					    (gnus-current-topic)
+					    (caar gnus-topic-topology)))
+					 gnus-topic-alist))
+		  (setq talist alist)
+		  (when (stringp yanked)
+		    (setq yanked (list yanked)))
+		  (if (not prev)
+		      (nconc alist yanked)
+		    (if (not (cdr alist))
+			(setcdr alist (nconc yanked (cdr alist)))
+		      (while (and (not end) (cdr alist))
+			(when (equal (cadr alist) prev)
+			  (setcdr alist (nconc yanked (cdr alist)))
+			  (setq end t))
+			(setq alist (cdr alist)))
+		      (unless end
+			(nconc talist yanked))))))
+	      (gnus-topic-update-topic))))))))
 
-(defun gnus-topic-update-topic-line (&optional topic level)
-  (unless topic
-    (setq topic gnus-topic-topology)
-    (setq level 0))
-  (let* ((type (pop topic))
-	 (buffer-read-only nil)
-	 (entries (gnus-topic-find-groups 
-		   (car type) (car gnus-group-list-mode)
-		   (cdr gnus-group-list-mode)))
-	 (visiblep (eq (nth 1 type) 'visible))
-	 (all-entries entries)
-	 (unread 0)
-	 entry)
-    ;; Tally any sub-topics.
-    (while topic
-      (incf unread (gnus-topic-update-topic-line (pop topic) (1+ level))))
-    ;; Tally all the groups that belong in this topic.
-    (while (setq entry (pop entries))
-      (when (numberp (car entry))
-	(incf unread (car entry))))
-    ;; Insert the topic line.
-    (when (gnus-topic-goto-topic (car type))
-      (gnus-topic-insert-topic-line 
-       (car type) visiblep
-       (not (eq (nth 2 type) 'hidden))
-       level all-entries unread)
-      (gnus-delete-line))
-    unread))
+(defun gnus-topic-goto-next-group (group props)
+  "Go to group or the next group after group."
+  (if (not group)
+      (if (not (memq 'gnus-topic props))
+	  (goto-char (point-max))
+	(gnus-topic-goto-topic (symbol-name (cadr (memq 'gnus-topic props)))))
+    (if (gnus-group-goto-group group)
+	t
+      ;; The group is no longer visible.
+      (let* ((list (assoc (gnus-group-topic group) gnus-topic-alist))
+	     (after (cdr (member group (cdr list)))))
+	;; First try to put point on a group after the current one.
+	(while (and after
+		    (not (gnus-group-goto-group (car after))))
+	  (setq after (cdr after)))
+	;; Then try to put point on a group before point.
+	(unless after
+	  (setq after (cdr (member group (reverse (cdr list)))))
+	  (while (and after
+		      (not (gnus-group-goto-group (car after))))
+	    (setq after (cdr after))))
+	;; Finally, just put point on the topic.
+	(if (not (car list))
+	    (goto-char (point-min))
+	  (unless after
+	    (gnus-topic-goto-topic (car list))
+	    (setq after nil)))
+	t))))
 
-(defun gnus-topic-grok-active (&optional force read-active)
+;;; Topic-active functions
+
+(defun gnus-topic-grok-active (&optional force)
   "Parse all active groups and create topic structures for them."
-  ;; First we make sure that we have really read the active file. 
+  ;; First we make sure that we have really read the active file.
   (when (or force
 	    (not gnus-topic-active-alist))
-    (when (and read-active
-	       (or force
-		   (not (member gnus-select-method 
-				gnus-have-read-active-file))))
-      (let ((gnus-read-active-file t))
-	(gnus-read-active-file)))
     (let (groups)
       ;; Get a list of all groups available.
       (mapatoms (lambda (g) (when (symbol-value g)
@@ -497,7 +885,7 @@ articles in the topic and its subtopics."
 		gnus-active-hashtb)
       (setq groups (sort groups 'string<))
       ;; Init the variables.
-      (setq gnus-topic-active-topology '(("" visible)))
+      (setq gnus-topic-active-topology (list (list "" 'visible)))
       (setq gnus-topic-active-alist nil)
       ;; Descend the top-level hierarchy.
       (gnus-topic-grok-active-1 gnus-topic-active-topology groups)
@@ -517,8 +905,8 @@ articles in the topic and its subtopics."
 	  ;; topic.
 	  (push (pop groups) tgroups)
 	;; New sub-hierarchy, so we add it to the topology.
-	(nconc topology (list (setq ntopology 
-				    (list (list (substring 
+	(nconc topology (list (setq ntopology
+				    (list (list (substring
 						 group 0 (match-end 0))
 						'invisible)))))
 	;; Descend the hierarchy.
@@ -535,12 +923,6 @@ articles in the topic and its subtopics."
     ;; to this topic.
     groups))
 
-(defun gnus-group-active-topic-p ()
-  "Return whether the current active comes from the active topics."
-  (save-excursion
-    (beginning-of-line)
-    (get-text-property (point) 'gnus-active)))
-
 ;;; Topic mode, commands and keymap.
 
 (defvar gnus-topic-mode-map nil)
@@ -550,33 +932,52 @@ articles in the topic and its subtopics."
   (setq gnus-topic-mode-map (make-sparse-keymap))
 
   ;; Override certain group mode keys.
-  (gnus-define-keys
-   gnus-topic-mode-map
-   "=" gnus-topic-select-group
-   "\r" gnus-topic-select-group
-   " " gnus-topic-read-group
-   "\C-k" gnus-topic-kill-group
-   "\C-y" gnus-topic-yank-group
-   "\M-g" gnus-topic-get-new-news-this-topic
-   "\C-i" gnus-topic-indent
-   "AT" gnus-topic-list-active
-   gnus-mouse-2 gnus-mouse-pick-topic)
+  (gnus-define-keys gnus-topic-mode-map
+    "=" gnus-topic-select-group
+    "\r" gnus-topic-select-group
+    " " gnus-topic-read-group
+    "\C-c\C-x" gnus-topic-expire-articles
+    "\C-k" gnus-topic-kill-group
+    "\C-y" gnus-topic-yank-group
+    "\M-g" gnus-topic-get-new-news-this-topic
+    "AT" gnus-topic-list-active
+    "Gp" gnus-topic-edit-parameters
+    "#" gnus-topic-mark-topic
+    "\M-#" gnus-topic-unmark-topic
+    [tab] gnus-topic-indent
+    [(meta tab)] gnus-topic-unindent
+    "\C-i" gnus-topic-indent
+    "\M-\C-i" gnus-topic-unindent
+    gnus-mouse-2 gnus-mouse-pick-topic)
 
   ;; Define a new submap.
-  (gnus-define-keys
-   (gnus-group-topic-map "T" gnus-group-mode-map)
-   "#" gnus-topic-mark-topic
-   "\M-#" gnus-topic-unmark-topic
-   "n" gnus-topic-create-topic
-   "m" gnus-topic-move-group
-   "D" gnus-topic-remove-group
-   "c" gnus-topic-copy-group
-   "h" gnus-topic-hide-topic
-   "s" gnus-topic-show-topic
-   "M" gnus-topic-move-matching
-   "C" gnus-topic-copy-matching
-   "r" gnus-topic-rename
-   "\177" gnus-topic-delete))
+  (gnus-define-keys (gnus-group-topic-map "T" gnus-group-mode-map)
+    "#" gnus-topic-mark-topic
+    "\M-#" gnus-topic-unmark-topic
+    "n" gnus-topic-create-topic
+    "m" gnus-topic-move-group
+    "D" gnus-topic-remove-group
+    "c" gnus-topic-copy-group
+    "h" gnus-topic-hide-topic
+    "s" gnus-topic-show-topic
+    "j" gnus-topic-jump-to-topic
+    "M" gnus-topic-move-matching
+    "C" gnus-topic-copy-matching
+    "\C-i" gnus-topic-indent
+    [tab] gnus-topic-indent
+    "r" gnus-topic-rename
+    "\177" gnus-topic-delete
+    [delete] gnus-topic-delete
+    "H" gnus-topic-toggle-display-empty-topics)
+
+  (gnus-define-keys (gnus-topic-sort-map "S" gnus-group-topic-map)
+    "s" gnus-topic-sort-groups
+    "a" gnus-topic-sort-groups-by-alphabet
+    "u" gnus-topic-sort-groups-by-unread
+    "l" gnus-topic-sort-groups-by-level
+    "v" gnus-topic-sort-groups-by-score
+    "r" gnus-topic-sort-groups-by-rank
+    "m" gnus-topic-sort-groups-by-method))
 
 (defun gnus-topic-make-menu-bar ()
   (unless (boundp 'gnus-topic-menu)
@@ -591,13 +992,17 @@ articles in the topic and its subtopics."
 	["Copy matching" gnus-topic-copy-matching t]
 	["Move matching" gnus-topic-move-matching t])
        ("Topics"
+	["Goto" gnus-topic-jump-to-topic t]
 	["Show" gnus-topic-show-topic t]
 	["Hide" gnus-topic-hide-topic t]
 	["Delete" gnus-topic-delete t]
 	["Rename" gnus-topic-rename t]
 	["Create" gnus-topic-create-topic t]
 	["Mark" gnus-topic-mark-topic t]
-	["Indent" gnus-topic-indent t])
+	["Indent" gnus-topic-indent t]
+	["Sort" gnus-topic-sort-topics t]
+	["Toggle hide empty" gnus-topic-toggle-display-empty-topics t]
+	["Edit parameters" gnus-topic-edit-parameters t])
        ["List active" gnus-topic-list-active t]))))
 
 (defun gnus-topic-mode (&optional arg redisplay)
@@ -605,54 +1010,59 @@ articles in the topic and its subtopics."
   (interactive (list current-prefix-arg t))
   (when (eq major-mode 'gnus-group-mode)
     (make-local-variable 'gnus-topic-mode)
-    (setq gnus-topic-mode 
+    (setq gnus-topic-mode
 	  (if (null arg) (not gnus-topic-mode)
 	    (> (prefix-numeric-value arg) 0)))
     ;; Infest Gnus with topics.
-    (when gnus-topic-mode
-      (when (and menu-bar-mode
-		 (gnus-visual-p 'topic-menu 'menu))
+    (if (not gnus-topic-mode)
+ 	(setq gnus-goto-missing-group-function nil)
+      (when (gnus-visual-p 'topic-menu 'menu)
 	(gnus-topic-make-menu-bar))
-      (setq gnus-topic-line-format-spec 
-	    (gnus-parse-format gnus-topic-line-format 
-			       gnus-topic-line-format-alist t))
-      (unless (assq 'gnus-topic-mode minor-mode-alist)
-	(push '(gnus-topic-mode " Topic") minor-mode-alist))
-      (unless (assq 'gnus-topic-mode minor-mode-map-alist)
-	(push (cons 'gnus-topic-mode gnus-topic-mode-map)
-	      minor-mode-map-alist))
-      (add-hook 'gnus-summary-exit-hook 'gnus-topic-update-topic)
+      (gnus-set-format 'topic t)
+      (gnus-add-minor-mode 'gnus-topic-mode " Topic" gnus-topic-mode-map)
       (add-hook 'gnus-group-catchup-group-hook 'gnus-topic-update-topic)
-      (make-local-variable 'gnus-group-prepare-function)
-      (setq gnus-group-prepare-function 'gnus-group-prepare-topics)
-      (make-local-variable 'gnus-group-goto-next-group-function)
-      (setq gnus-group-goto-next-group-function 
-	    'gnus-topic-goto-next-group)
+      (set (make-local-variable 'gnus-group-prepare-function)
+	   'gnus-group-prepare-topics)
+      (set (make-local-variable 'gnus-group-get-parameter-function)
+	   'gnus-group-topic-parameters)
+      (set (make-local-variable 'gnus-group-goto-next-group-function)
+	   'gnus-topic-goto-next-group)
+      (set (make-local-variable 'gnus-group-indentation-function)
+	   'gnus-topic-group-indentation)
+      (set (make-local-variable 'gnus-group-update-group-function)
+	   'gnus-topic-update-topics-containing-group)
+      (set (make-local-variable 'gnus-group-sort-alist-function)
+	   'gnus-group-sort-topic)
       (setq gnus-group-change-level-function 'gnus-topic-change-level)
       (setq gnus-goto-missing-group-function 'gnus-topic-goto-missing-group)
-      (make-local-variable 'gnus-group-indentation-function)
-      (setq gnus-group-indentation-function
-	    'gnus-topic-group-indentation)
+      (make-local-hook 'gnus-check-bogus-groups-hook)
+      (add-hook 'gnus-check-bogus-groups-hook 'gnus-topic-clean-alist)
+      (setq gnus-topology-checked-p nil)
       ;; We check the topology.
-      (gnus-topic-check-topology)
-      (run-hooks 'gnus-topic-mode-hook))
+      (when gnus-newsrc-alist
+	(gnus-topic-check-topology))
+      (gnus-run-hooks 'gnus-topic-mode-hook))
     ;; Remove topic infestation.
     (unless gnus-topic-mode
       (remove-hook 'gnus-summary-exit-hook 'gnus-topic-update-topic)
-      (remove-hook 'gnus-group-change-level-function 
+      (remove-hook 'gnus-group-change-level-function
 		   'gnus-topic-change-level)
-      (setq gnus-group-prepare-function 'gnus-group-prepare-flat))
+      (remove-hook 'gnus-check-bogus-groups-hook 'gnus-topic-clean-alist)
+      (setq gnus-group-prepare-function 'gnus-group-prepare-flat)
+      (setq gnus-group-sort-alist-function 'gnus-group-sort-flat))
     (when redisplay
       (gnus-group-list-groups))))
-    
+
 (defun gnus-topic-select-group (&optional all)
   "Select this newsgroup.
 No article is selected automatically.
 If ALL is non-nil, already read articles become readable.
-If ALL is a number, fetch this number of articles."
+If ALL is a number, fetch this number of articles.
+
+If performed over a topic line, toggle folding the topic."
   (interactive "P")
   (if (gnus-group-topic-p)
-      (let ((gnus-group-list-mode 
+      (let ((gnus-group-list-mode
 	     (if all (cons (if (numberp all) all 7) t) gnus-group-list-mode)))
 	(gnus-topic-fold all))
     (gnus-group-select-group all)))
@@ -663,29 +1073,45 @@ If ALL is a number, fetch this number of articles."
   (mouse-set-point e)
   (gnus-topic-read-group nil))
 
+(defun gnus-topic-expire-articles (topic)
+  "Expire articles in this topic or group."
+  (interactive (list (gnus-group-topic-name)))
+  (if (not topic)
+      (call-interactively 'gnus-group-expire-articles)
+    (save-excursion
+      (gnus-message 5 "Expiring groups in %s..." topic)
+      (let ((gnus-group-marked
+	     (mapcar (lambda (entry) (car (nth 2 entry)))
+		     (gnus-topic-find-groups topic gnus-level-killed t))))
+	(gnus-group-expire-articles nil))
+      (gnus-message 5 "Expiring groups in %s...done" topic))))
+
 (defun gnus-topic-read-group (&optional all no-article group)
   "Read news in this newsgroup.
 If the prefix argument ALL is non-nil, already read articles become
 readable.  IF ALL is a number, fetch this number of articles.  If the
 optional argument NO-ARTICLE is non-nil, no article will be
 auto-selected upon group entry.  If GROUP is non-nil, fetch that
-group."
+group.
+
+If performed over a topic line, toggle folding the topic."
   (interactive "P")
   (if (gnus-group-topic-p)
-      (let ((gnus-group-list-mode 
+      (let ((gnus-group-list-mode
 	     (if all (cons (if (numberp all) all 7) t) gnus-group-list-mode)))
 	(gnus-topic-fold all))
     (gnus-group-read-group all no-article group)))
 
 (defun gnus-topic-create-topic (topic parent &optional previous full-topic)
-  (interactive 
+  "Create a new TOPIC under PARENT.
+When used interactively, PARENT will be the topic under point."
+  (interactive
    (list
-    (read-string "Create topic: ")
-    (completing-read "Parent topic: " gnus-topic-alist nil t
-		     (cons (gnus-group-parent-topic) 0))))
+    (read-string "New topic: ")
+    (gnus-current-topic)))
   ;; Check whether this topic already exists.
   (when (gnus-topic-find-topology topic)
-    (error "Topic aleady exists"))
+    (error "Topic already exists"))
   (unless parent
     (setq parent (caar gnus-topic-topology)))
   (let ((top (cdr (gnus-topic-find-topology parent)))
@@ -702,38 +1128,62 @@ group."
     (unless (assoc topic gnus-topic-alist)
       (push (list topic) gnus-topic-alist)))
   (gnus-topic-enter-dribble)
-  (gnus-group-list-groups))
+  (gnus-group-list-groups)
+  (gnus-topic-goto-topic topic))
+
+;; FIXME: 
+;;  1. When the marked groups are overlapped with the process 
+;;     region, the behavior of move or remove is not right.
+;;  2. Can't process on several marked groups with a same name, 
+;;     because gnus-group-marked only keeps one copy.
 
 (defun gnus-topic-move-group (n topic &optional copyp)
-  "Move the current group to a topic."
+  "Move the next N groups to TOPIC.
+If COPYP, copy the groups instead."
   (interactive
    (list current-prefix-arg
 	 (completing-read "Move to topic: " gnus-topic-alist nil t)))
-  (let ((groups (gnus-group-process-prefix n))
+  (let ((use-marked (and (not n) (not (gnus-region-active-p)) 
+			 gnus-group-marked t))
+	(groups (gnus-group-process-prefix n))
 	(topicl (assoc topic gnus-topic-alist))
+	(start-topic (gnus-group-topic-name))
+	(start-group (progn (forward-line 1) (gnus-group-group-name)))
 	entry)
-    (mapcar (lambda (g) 
-	      (gnus-group-remove-mark g)
-	      (when (and
-		     (setq entry (assoc (gnus-group-topic g) gnus-topic-alist))
-		     (not copyp))
-		(setcdr entry (delete g (cdr entry))))
-	      (when topicl
-		(nconc topicl (list g))))
-	    groups)
-    (gnus-group-position-point))
-  (gnus-topic-enter-dribble)
-  (gnus-group-list-groups))
+    (if (and (not groups) (not copyp) start-topic)
+	(gnus-topic-move start-topic topic)
+      (mapcar
+       (lambda (g)
+	 (gnus-group-remove-mark g use-marked)
+	 (when (and
+		(setq entry (assoc (gnus-current-topic) gnus-topic-alist))
+		(not copyp))
+	   (setcdr entry (gnus-delete-first g (cdr entry))))
+	 (nconc topicl (list g)))
+       groups)
+      (gnus-topic-enter-dribble)
+      (if start-group
+	  (gnus-group-goto-group start-group)
+	(gnus-topic-goto-topic start-topic))
+      (gnus-group-list-groups))))
 
-(defun gnus-topic-remove-group ()
+(defun gnus-topic-remove-group (&optional n)
   "Remove the current group from the topic."
-  (interactive)
-  (let ((topicl (assoc (gnus-group-parent-topic) gnus-topic-alist))
-	(group (gnus-group-group-name))
-	(buffer-read-only nil))
-    (when (and topicl group)
-      (gnus-delete-line)
-      (delq (gnus-group-group-name) topicl))
+  (interactive "P")
+  (let ((use-marked (and (not n) (not (gnus-region-active-p)) 
+			 gnus-group-marked t))
+	(groups (gnus-group-process-prefix n)))
+    (mapcar
+     (lambda (group)
+       (gnus-group-remove-mark group use-marked)
+       (let ((topicl (assoc (gnus-current-topic) gnus-topic-alist))
+	     (buffer-read-only nil))
+	 (when (and topicl group)
+	   (gnus-delete-line)
+	   (gnus-delete-first group topicl))
+	 (gnus-topic-update-topic)))
+     groups)
+    (gnus-topic-enter-dribble)
     (gnus-group-position-point)))
 
 (defun gnus-topic-copy-group (n topic)
@@ -743,117 +1193,55 @@ group."
 	 (completing-read "Copy to topic: " gnus-topic-alist nil t)))
   (gnus-topic-move-group n topic t))
 
-(defun gnus-topic-group-indentation ()
-  (make-string 
-   (* gnus-topic-indent-level
-      (or (save-excursion
-	    (gnus-topic-goto-topic (gnus-group-parent-topic))
-	    (gnus-group-topic-level)) 0)) ? ))
-
-(defun gnus-topic-change-level (group level oldlevel)
-  "Run when changing levels to enter/remove groups from topics."
-  (when (and gnus-topic-mode 
-	     gnus-topic-alist
-	     (not gnus-topic-inhibit-change-level))
-    ;; Remove the group from the topics.
-    (when (and (< oldlevel gnus-level-zombie)
-	       (>= level gnus-level-zombie))
-      (let (alist)
-	(when (setq alist (assoc (gnus-group-topic group) gnus-topic-alist))
-	  (setcdr alist (delete group (cdr alist))))))
-    ;; If the group is subscribed. then we enter it into the topics.
-    (when (and (< level gnus-level-zombie)
-	       (>= oldlevel gnus-level-zombie))
-      (let* ((prev (gnus-group-group-name))
-	     (gnus-topic-inhibit-change-level t)
-	     (gnus-group-indentation
-	      (make-string 
-	       (* gnus-topic-indent-level
-		  (or (save-excursion
-			(gnus-topic-goto-topic (gnus-group-parent-topic))
-			(gnus-group-topic-level)) 0)) ? ))
-	     (yanked (list group))
-	     alist)
-	;; Then we enter the yanked groups into the topics they belong
-	;; to. 
-	(setq alist (assoc (save-excursion
-			     (forward-line -1)
-			     (gnus-group-parent-topic))
-			   gnus-topic-alist))
-	(when (stringp yanked)
-	  (setq yanked (list yanked)))
-	(if (not prev)
-	    (nconc alist yanked)
-	  (if (not (cdr alist))
-	      (setcdr alist (nconc yanked (cdr alist)))
-	    (while (cdr alist)
-	      (when (equal (cadr alist) prev)
-		(setcdr alist (nconc yanked (cdr alist)))
-		(setq alist nil))
-	      (setq alist (cdr alist))))))
-      (gnus-topic-update-topic))))
-
-(defun gnus-topic-goto-next-group (group props)
-  "Go to group or the next group after group."
-  (if (null group)
-      (gnus-topic-goto-topic (symbol-name (cadr (memq 'gnus-topic props))))
-    (if (gnus-group-goto-group group)
-	t
-      ;; The group is no longer visible.
-      (let* ((list (assoc (gnus-group-topic group) gnus-topic-alist))
-	     (after (cdr (member group (cdr list)))))
-	;; First try to put point on a group after the current one.
-	(while (and after
-		    (not (gnus-group-goto-group (car after))))
-	  (setq after (cdr after)))
-	;; Then try to put point on a group before point.
-	(unless after
-	  (setq after (cdr (member group (reverse (cdr list)))))
-	  (while (and after 
-		      (not (gnus-group-goto-group (car after))))
-	    (setq after (cdr after))))
-	;; Finally, just put point on the topic.
-	(unless after
-	  (gnus-topic-goto-topic (car list))
-	  (setq after nil))
-	t))))
-
 (defun gnus-topic-kill-group (&optional n discard)
   "Kill the next N groups."
   (interactive "P")
   (if (gnus-group-topic-p)
       (let ((topic (gnus-group-topic-name)))
+	(push (cons
+	       (gnus-topic-find-topology topic)
+	       (assoc topic gnus-topic-alist))
+	      gnus-topic-killed-topics)
 	(gnus-topic-remove-topic nil t)
-	(push (gnus-topic-find-topology topic nil nil gnus-topic-topology)
-	      gnus-topic-killed-topics))
+	(gnus-topic-find-topology topic nil nil gnus-topic-topology)
+	(gnus-topic-enter-dribble))
     (gnus-group-kill-group n discard)
     (gnus-topic-update-topic)))
-  
+
 (defun gnus-topic-yank-group (&optional arg)
   "Yank the last topic."
   (interactive "p")
   (if gnus-topic-killed-topics
-      (let ((previous (gnus-group-parent-topic))
-	    (item (cdr (pop gnus-topic-killed-topics))))
+      (let* ((previous
+	      (or (gnus-group-topic-name)
+		  (gnus-topic-next-topic (gnus-current-topic))))
+	     (data (pop gnus-topic-killed-topics))
+	     (alist (cdr data))
+	     (item (cdar data)))
+	(push alist gnus-topic-alist)
 	(gnus-topic-create-topic
 	 (caar item) (gnus-topic-parent-topic previous) previous
-	 item))
+	 item)
+	(gnus-topic-enter-dribble)
+	(gnus-topic-goto-topic (caar item)))
     (let* ((prev (gnus-group-group-name))
 	   (gnus-topic-inhibit-change-level t)
 	   (gnus-group-indentation
-	    (make-string 
+	    (make-string
 	     (* gnus-topic-indent-level
 		(or (save-excursion
-		      (gnus-topic-goto-topic (gnus-group-parent-topic))
-		      (gnus-group-topic-level)) 0)) ? ))
+		      (gnus-topic-goto-topic (gnus-current-topic))
+		      (gnus-group-topic-level))
+		    0))
+	     ? ))
 	   yanked alist)
       ;; We first yank the groups the normal way...
       (setq yanked (gnus-group-yank-group arg))
       ;; Then we enter the yanked groups into the topics they belong
-      ;; to. 
+      ;; to.
       (setq alist (assoc (save-excursion
 			   (forward-line -1)
-			   (gnus-group-parent-topic))
+			   (gnus-current-topic))
 			 gnus-topic-alist))
       (when (stringp yanked)
 	(setq yanked (list yanked)))
@@ -869,31 +1257,35 @@ group."
     (gnus-topic-update-topic)))
 
 (defun gnus-topic-hide-topic ()
-  "Hide all subtopics under the current topic."
+  "Hide the current topic."
   (interactive)
-  (when (gnus-group-parent-topic)
-    (gnus-topic-goto-topic (gnus-group-parent-topic))
-    (gnus-topic-remove-topic nil nil 'hidden)))
+  (when (gnus-current-topic)
+    (gnus-topic-goto-topic (gnus-current-topic))
+    (gnus-topic-remove-topic nil nil)))
 
 (defun gnus-topic-show-topic ()
   "Show the hidden topic."
   (interactive)
   (when (gnus-group-topic-p)
-    (gnus-topic-remove-topic t nil 'shown)))
+    (gnus-topic-remove-topic t nil)))
 
 (defun gnus-topic-mark-topic (topic &optional unmark)
   "Mark all groups in the topic with the process mark."
-  (interactive (list (gnus-group-parent-topic)))
-  (save-excursion
-    (let ((groups (gnus-topic-find-groups topic 9 t)))
-      (while groups
-	(funcall (if unmark 'gnus-group-remove-mark 'gnus-group-set-mark)
-		 (gnus-info-group (nth 2 (pop groups))))))))
+  (interactive (list (gnus-group-topic-name)))
+  (if (not topic)
+      (call-interactively 'gnus-group-mark-group)
+    (save-excursion
+      (let ((groups (gnus-topic-find-groups topic gnus-level-killed t)))
+	(while groups
+	  (funcall (if unmark 'gnus-group-remove-mark 'gnus-group-set-mark)
+		   (gnus-info-group (nth 2 (pop groups)))))))))
 
 (defun gnus-topic-unmark-topic (topic &optional unmark)
   "Remove the process mark from all groups in the topic."
-  (interactive (list (gnus-group-parent-topic)))
-  (gnus-topic-mark-topic topic t))
+  (interactive (list (gnus-group-topic-name)))
+  (if (not topic)
+      (call-interactively 'gnus-group-unmark-group)
+    (gnus-topic-mark-topic topic t)))
 
 (defun gnus-topic-get-new-news-this-topic (&optional n)
   "Check for new news in the current topic."
@@ -939,23 +1331,33 @@ group."
     ;; Remove from alist.
     (setq gnus-topic-alist (delq entry gnus-topic-alist))
     ;; Remove from topology.
-    (gnus-topic-find-topology topic nil nil 'delete)))
+    (gnus-topic-find-topology topic nil nil 'delete)
+    (gnus-dribble-touch)))
 
 (defun gnus-topic-rename (old-name new-name)
   "Rename a topic."
   (interactive
-   (let (topic)
-     (list
-      (setq topic (completing-read "Rename topic: " gnus-topic-alist nil t
-				   (cons (gnus-group-parent-topic) 0)))
-      (read-string (format "Rename %s to: " topic)))))
+   (let ((topic (gnus-current-topic)))
+     (list topic
+	   (read-string (format "Rename %s to: " topic)))))
+  ;; Check whether the new name exists.
+  (when (gnus-topic-find-topology new-name)
+    (error "Topic '%s' already exists" new-name))
+  ;; "nil" is an invalid name, for reasons I'd rather not go
+  ;; into here.  Trust me.
+  (when (equal new-name "nil")
+    (error "Invalid name: %s" nil))
+  ;; Do the renaming.
   (let ((top (gnus-topic-find-topology old-name))
 	(entry (assoc old-name gnus-topic-alist)))
     (when top
       (setcar (cadr top) new-name))
-    (when entry 
+    (when entry
       (setcar entry new-name))
-    (gnus-group-list-groups)))
+    (forward-line -1)
+    (gnus-dribble-touch)
+    (gnus-group-list-groups)
+    (forward-line 1)))
 
 (defun gnus-topic-indent (&optional unindent)
   "Indent a topic -- make it a sub-topic of the previous topic.
@@ -963,20 +1365,25 @@ If UNINDENT, remove an indentation."
   (interactive "P")
   (if unindent
       (gnus-topic-unindent)
-    (let* ((topic (gnus-group-parent-topic))
-	   (parent (gnus-topic-previous-topic topic)))
+    (let* ((topic (gnus-current-topic))
+	   (parent (gnus-topic-previous-topic topic))
+	   (buffer-read-only nil))
       (unless parent
 	(error "Nothing to indent %s into" topic))
       (when topic
 	(gnus-topic-goto-topic topic)
 	(gnus-topic-kill-group)
-	(gnus-topic-create-topic topic parent)
-	(gnus-topic-goto-topic topic)))))
+	(push (cdar gnus-topic-killed-topics) gnus-topic-alist)
+	(gnus-topic-create-topic
+	 topic parent nil (cdaar gnus-topic-killed-topics))
+	(pop gnus-topic-killed-topics)
+	(or (gnus-topic-goto-topic topic)
+	    (gnus-topic-goto-topic parent))))))
 
 (defun gnus-topic-unindent ()
   "Unindent a topic."
   (interactive)
-  (let* ((topic (gnus-group-parent-topic))
+  (let* ((topic (gnus-current-topic))
 	 (parent (gnus-topic-parent-topic topic))
 	 (grandparent (gnus-topic-parent-topic parent)))
     (unless grandparent
@@ -984,19 +1391,188 @@ If UNINDENT, remove an indentation."
     (when topic
       (gnus-topic-goto-topic topic)
       (gnus-topic-kill-group)
-      (gnus-topic-create-topic topic grandparent)
+      (push (cdar gnus-topic-killed-topics) gnus-topic-alist)
+      (gnus-topic-create-topic
+       topic grandparent (gnus-topic-next-topic parent)
+       (cdaar gnus-topic-killed-topics))
+      (pop gnus-topic-killed-topics)
       (gnus-topic-goto-topic topic))))
 
 (defun gnus-topic-list-active (&optional force)
   "List all groups that Gnus knows about in a topicsified fashion.
 If FORCE, always re-read the active file."
   (interactive "P")
-  (gnus-topic-grok-active force force)
+  (when force
+    (gnus-get-killed-groups))
+  (gnus-topic-grok-active force)
   (let ((gnus-topic-topology gnus-topic-active-topology)
 	(gnus-topic-alist gnus-topic-active-alist)
 	gnus-killed-list gnus-zombie-list)
-    (gnus-group-list-groups 9 nil 1)))
+    (gnus-group-list-groups gnus-level-killed nil 1)))
 
+(defun gnus-topic-toggle-display-empty-topics ()
+  "Show/hide topics that have no unread articles."
+  (interactive)
+  (setq gnus-topic-display-empty-topics
+	(not gnus-topic-display-empty-topics))
+  (gnus-group-list-groups)
+  (message "%s empty topics"
+	   (if gnus-topic-display-empty-topics
+	       "Showing" "Hiding")))
+
+;;; Topic sorting functions
+
+(defun gnus-topic-edit-parameters (group)
+  "Edit the group parameters of GROUP.
+If performed on a topic, edit the topic parameters instead."
+  (interactive (list (gnus-group-group-name)))
+  (if group
+      (gnus-group-edit-group-parameters group)
+    (if (not (gnus-group-topic-p))
+	(error "Nothing to edit on the current line")
+      (let ((topic (gnus-group-topic-name)))
+	(gnus-edit-form
+	 (gnus-topic-parameters topic)
+	 (format "Editing the topic parameters for `%s'."
+		 (or group topic))
+	 `(lambda (form)
+	    (gnus-topic-set-parameters ,topic form)))))))
+
+(defun gnus-group-sort-topic (func reverse)
+  "Sort groups in the topics according to FUNC and REVERSE."
+  (let ((alist gnus-topic-alist))
+    (while alist
+      ;; !!!Sometimes nil elements sneak into the alist,
+      ;; for some reason or other.
+      (setcar alist (delq nil (car alist)))
+      (setcar alist (delete "dummy.group" (car alist)))
+      (gnus-topic-sort-topic (pop alist) func reverse))))
+
+(defun gnus-topic-sort-topic (topic func reverse)
+  ;; Each topic only lists the name of the group, while
+  ;; the sort predicates expect group infos as inputs.
+  ;; So we first transform the group names into infos,
+  ;; then sort, and then transform back into group names.
+  (setcdr
+   topic
+   (mapcar
+    (lambda (info) (gnus-info-group info))
+    (sort
+     (mapcar
+      (lambda (group) (gnus-get-info group))
+      (cdr topic))
+     func)))
+  ;; Do the reversal, if necessary.
+  (when reverse
+    (setcdr topic (nreverse (cdr topic)))))
+
+(defun gnus-topic-sort-groups (func &optional reverse)
+  "Sort the current topic according to FUNC.
+If REVERSE, reverse the sorting order."
+  (interactive (list gnus-group-sort-function current-prefix-arg))
+  (let ((topic (assoc (gnus-current-topic) gnus-topic-alist)))
+    (gnus-topic-sort-topic
+     topic (gnus-make-sort-function func) reverse)
+    (gnus-group-list-groups)))
+
+(defun gnus-topic-sort-groups-by-alphabet (&optional reverse)
+  "Sort the current topic alphabetically by group name.
+If REVERSE, sort in reverse order."
+  (interactive "P")
+  (gnus-topic-sort-groups 'gnus-group-sort-by-alphabet reverse))
+
+(defun gnus-topic-sort-groups-by-unread (&optional reverse)
+  "Sort the current topic by number of unread articles.
+If REVERSE, sort in reverse order."
+  (interactive "P")
+  (gnus-topic-sort-groups 'gnus-group-sort-by-unread reverse))
+
+(defun gnus-topic-sort-groups-by-level (&optional reverse)
+  "Sort the current topic by group level.
+If REVERSE, sort in reverse order."
+  (interactive "P")
+  (gnus-topic-sort-groups 'gnus-group-sort-by-level reverse))
+
+(defun gnus-topic-sort-groups-by-score (&optional reverse)
+  "Sort the current topic by group score.
+If REVERSE, sort in reverse order."
+  (interactive "P")
+  (gnus-topic-sort-groups 'gnus-group-sort-by-score reverse))
+
+(defun gnus-topic-sort-groups-by-rank (&optional reverse)
+  "Sort the current topic by group rank.
+If REVERSE, sort in reverse order."
+  (interactive "P")
+  (gnus-topic-sort-groups 'gnus-group-sort-by-rank reverse))
+
+(defun gnus-topic-sort-groups-by-method (&optional reverse)
+  "Sort the current topic alphabetically by backend name.
+If REVERSE, sort in reverse order."
+  (interactive "P")
+  (gnus-topic-sort-groups 'gnus-group-sort-by-method reverse))
+
+(defun gnus-topic-sort-topics-1 (top reverse)
+  (if (cdr top)
+      (let ((subtop
+	     (mapcar `(lambda (top)
+			(gnus-topic-sort-topics-1 top ,reverse))
+		     (sort (cdr top)
+			   '(lambda (t1 t2) 
+			      (string-lessp (caar t1) (caar t2)))))))
+	(setcdr top (if reverse (reverse subtop) subtop))))
+  top)
+
+(defun gnus-topic-sort-topics (&optional topic reverse)
+  "Sort topics in TOPIC alphabeticaly by topic name.
+If REVERSE, reverse the sorting order."
+  (interactive 
+   (list (completing-read "Sort topics in : " gnus-topic-alist nil t 
+			  (gnus-current-topic))
+	 current-prefix-arg))
+  (let ((topic-topology (or (and topic (cdr (gnus-topic-find-topology topic)))
+			    gnus-topic-topology)))
+    (gnus-topic-sort-topics-1 topic-topology reverse)
+    (gnus-topic-enter-dribble)
+    (gnus-group-list-groups)
+    (gnus-topic-goto-topic topic)))
+
+(defun gnus-topic-move (current to)
+  "Move the CURRENT topic to TO."
+  (interactive 
+   (list 
+    (gnus-group-topic-name)
+    (completing-read "Move to topic: " gnus-topic-alist nil t)))
+  (unless (and current to)
+    (error "Can't find topic"))
+  (let ((current-top (cdr (gnus-topic-find-topology current)))
+	(to-top (cdr (gnus-topic-find-topology to))))
+    (unless current-top
+      (error "Can't find topic `%s'" current))
+    (unless to-top
+      (error "Can't find topic `%s'" to))
+    (if (gnus-topic-find-topology to current-top 0);; Don't care the level
+	(error "Can't move `%s' to its sub-level" current))
+    (gnus-topic-find-topology current nil nil 'delete)
+    (while (cdr to-top)
+      (setq to-top (cdr to-top)))
+    (setcdr to-top (list current-top))
+    (gnus-topic-enter-dribble)
+    (gnus-group-list-groups)
+    (gnus-topic-goto-topic current)))
+
+(defun gnus-subscribe-topics (newsgroup)
+  (catch 'end
+    (let (match gnus-group-change-level-function)
+      (dolist (topic (gnus-topic-list))
+	(when (and (setq match (cdr (assq 'subscribe
+					  (gnus-topic-parameters topic))))
+		   (string-match match newsgroup))
+	  ;; Just subscribe the group.
+	  (gnus-subscribe-alphabetically newsgroup)
+	  ;; Add the group to the topic.
+	  (nconc (assoc topic gnus-topic-alist) (list newsgroup))
+	  (throw 'end t))))))
+	  
 (provide 'gnus-topic)
 
 ;;; gnus-topic.el ends here