lisp/gnus/gnus-topic.el

   1 ;;; gnus-topic.el --- a folding minor mode for Gnus group buffers
   2
   3 ;; Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
   4 ;;   2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
   5
   6 ;; Author: Ilja Weis <kult@uni-paderborn.de>
   7 ;;      Lars Magne Ingebrigtsen <larsi@gnus.org>
   8 ;; Keywords: news
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software: you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation, either version 3 of the License, or
  15 ;; (at your option) any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26
  27 ;;; Code:
  28
  29 (eval-when-compile (require 'cl))
  30
  31 (require 'gnus)
  32 (require 'gnus-group)
  33 (require 'gnus-start)
  34 (require 'gnus-util)
  35
  36 (defgroup gnus-topic nil
  37   "Group topics."
  38   :group 'gnus-group)
  39
  40 (defvar gnus-topic-mode nil
  41   "Minor mode for Gnus group buffers.")
  42
  43 (defcustom gnus-topic-mode-hook nil
  44   "Hook run in topic mode buffers."
  45   :type 'hook
  46   :group 'gnus-topic)
  47
  48 (when (featurep 'xemacs)
  49   (add-hook 'gnus-topic-mode-hook 'gnus-xmas-topic-menu-add))
  50
  51 (defcustom gnus-topic-line-format "%i[ %(%{%n%}%) -- %A ]%v\n"
  52   "Format of topic lines.
  53 It works along the same lines as a normal formatting string,
  54 with some simple extensions.
  55
  56 %i  Indentation based on topic level.
  57 %n  Topic name.
  58 %v  Nothing if the topic is visible, \"...\" otherwise.
  59 %g  Number of groups in the topic.
  60 %a  Number of unread articles in the groups in the topic.
  61 %A  Number of unread articles in the groups in the topic and its subtopics.
  62
  63 General format specifiers can also be used.
  64 See Info node `(gnus)Formatting Variables'."
  65   :link '(custom-manual "(gnus)Formatting Variables")
  66   :type 'string
  67   :group 'gnus-topic)
  68
  69 (defcustom gnus-topic-indent-level 2
  70   "*How much each subtopic should be indented."
  71   :type 'integer
  72   :group 'gnus-topic)
  73
  74 (defcustom gnus-topic-display-empty-topics t
  75   "*If non-nil, display the topic lines even of topics that have no unread articles."
  76   :type 'boolean
  77   :group 'gnus-topic)
  78
  79 ;; Internal variables.
  80
  81 (defvar gnus-topic-active-topology nil)
  82 (defvar gnus-topic-active-alist nil)
  83 (defvar gnus-topic-unreads nil)
  84
  85 (defvar gnus-topology-checked-p nil
  86   "Whether the topology has been checked in this session.")
  87
  88 (defvar gnus-topic-killed-topics nil)
  89 (defvar gnus-topic-inhibit-change-level nil)
  90
  91 (defconst gnus-topic-line-format-alist
  92   `((?n name ?s)
  93     (?v visible ?s)
  94     (?i indentation ?s)
  95     (?g number-of-groups ?d)
  96     (?a (gnus-topic-articles-in-topic entries) ?d)
  97     (?A total-number-of-articles ?d)
  98     (?l level ?d)))
  99
 100 (defvar gnus-topic-line-format-spec nil)
 101
 102 ;;; Utility functions
 103
 104 (defun gnus-group-topic-name ()
 105   "The name of the topic on the current line."
 106   (let ((topic (get-text-property (point-at-bol) 'gnus-topic)))
 107     (and topic (symbol-name topic))))
 108
 109 (defun gnus-group-topic-level ()
 110   "The level of the topic on the current line."
 111   (get-text-property (point-at-bol) 'gnus-topic-level))
 112
 113 (defun gnus-group-topic-unread ()
 114   "The number of unread articles in topic on the current line."
 115   (get-text-property (point-at-bol) 'gnus-topic-unread))
 116
 117 (defun gnus-topic-unread (topic)
 118   "Return the number of unread articles in TOPIC."
 119   (or (cdr (assoc topic gnus-topic-unreads))
 120       0))
 121
 122 (defun gnus-group-topic-p ()
 123   "Return non-nil if the current line is a topic."
 124   (gnus-group-topic-name))
 125
 126 (defun gnus-topic-visible-p ()
 127   "Return non-nil if the current topic is visible."
 128   (get-text-property (point-at-bol) 'gnus-topic-visible))
 129
 130 (defun gnus-topic-articles-in-topic (entries)
 131   (let ((total 0)
 132         number)
 133     (while entries
 134       (when (numberp (setq number (car (pop entries))))
 135         (incf total number)))
 136     total))
 137
 138 (defun gnus-group-topic (group)
 139   "Return the topic GROUP is a member of."
 140   (let ((alist gnus-topic-alist)
 141         out)
 142     (while alist
 143       (when (member group (cdar alist))
 144         (setq out (caar alist)
 145               alist nil))
 146       (setq alist (cdr alist)))
 147     out))
 148
 149 (defun gnus-group-parent-topic (group)
 150   "Return the topic GROUP is member of by looking at the group buffer."
 151   (save-excursion
 152     (set-buffer gnus-group-buffer)
 153     (if (gnus-group-goto-group group)
 154         (gnus-current-topic)
 155       (gnus-group-topic group))))
 156
 157 (defun gnus-topic-goto-topic (topic)
 158   (when topic
 159     (gnus-goto-char (text-property-any (point-min) (point-max)
 160                                        'gnus-topic (intern topic)))))
 161
 162 (defun gnus-topic-jump-to-topic (topic)
 163   "Go to TOPIC."
 164   (interactive
 165    (list (completing-read "Go to topic: "
 166                           (mapcar 'list (gnus-topic-list))
 167                           nil t)))
 168   (let ((buffer-read-only nil))
 169     (dolist (topic (gnus-current-topics topic))
 170       (unless (gnus-topic-goto-topic topic)
 171         (gnus-topic-goto-missing-topic topic)
 172         (gnus-topic-display-missing-topic topic))))
 173   (gnus-topic-goto-topic topic))
 174
 175 (defun gnus-current-topic ()
 176   "Return the name of the current topic."
 177   (let ((result
 178          (or (get-text-property (point) 'gnus-topic)
 179              (save-excursion
 180                (and (gnus-goto-char (previous-single-property-change
 181                                      (point) 'gnus-topic))
 182                     (get-text-property (max (1- (point)) (point-min))
 183                                        'gnus-topic))))))
 184     (when result
 185       (symbol-name result))))
 186
 187 (defun gnus-current-topics (&optional topic)
 188   "Return a list of all current topics, lowest in hierarchy first.
 189 If TOPIC, start with that topic."
 190   (let ((topic (or topic (gnus-current-topic)))
 191         topics)
 192     (while topic
 193       (push topic topics)
 194       (setq topic (gnus-topic-parent-topic topic)))
 195     (nreverse topics)))
 196
 197 (defun gnus-group-active-topic-p ()
 198   "Say whether the current topic comes from the active topics."
 199   (get-text-property (point-at-bol) 'gnus-active))
 200
 201 (defun gnus-topic-find-groups (topic &optional level all lowest recursive)
 202   "Return entries for all visible groups in TOPIC.
 203 If RECURSIVE is t, return groups in its subtopics too."
 204   (let ((groups (cdr (assoc topic gnus-topic-alist)))
 205         info clevel unread group params visible-groups entry active)
 206     (setq lowest (or lowest 1))
 207     (setq level (or level gnus-level-unsubscribed))
 208     ;; We go through the newsrc to look for matches.
 209     (while groups
 210       (when (setq group (pop groups))
 211         (setq entry (gnus-group-entry group)
 212               info (nth 2 entry)
 213               params (gnus-info-params info)
 214               active (gnus-active group)
 215               unread (or (car entry)
 216                          (and (not (equal group "dummy.group"))
 217                               active
 218                               (- (1+ (cdr active)) (car active))))
 219               clevel (or (gnus-info-level info)
 220                          (if (member group gnus-zombie-list)
 221                              gnus-level-zombie gnus-level-killed))))
 222       (and
 223        info                             ; nil means that the group is dead.
 224        (<= clevel level)
 225        (>= clevel lowest)               ; Is inside the level we want.
 226        (or all
 227            (if (or (eq unread t)
 228                    (eq unread nil))
 229                gnus-group-list-inactive-groups
 230              (> unread 0))
 231            (and gnus-list-groups-with-ticked-articles
 232                 (cdr (assq 'tick (gnus-info-marks info))))
 233            ;; Has right readedness.
 234            ;; Check for permanent visibility.
 235            (and gnus-permanently-visible-groups
 236                 (string-match gnus-permanently-visible-groups group))
 237            (memq 'visible params)
 238            (cdr (assq 'visible params)))
 239        ;; Add this group to the list of visible groups.
 240        (push (or entry group) visible-groups)))
 241     (setq visible-groups (nreverse visible-groups))
 242     (when recursive
 243       (if (eq recursive t)
 244           (setq recursive (cdr (gnus-topic-find-topology topic))))
 245       (dolist (topic-topology (cdr recursive))
 246         (setq visible-groups
 247               (nconc visible-groups
 248                      (gnus-topic-find-groups
 249                       (caar topic-topology)
 250                       level all lowest topic-topology)))))
 251     visible-groups))
 252
 253 (defun gnus-topic-goto-previous-topic (n)
 254   "Go to the N'th previous topic."
 255   (interactive "p")
 256   (gnus-topic-goto-next-topic (- n)))
 257
 258 (defun gnus-topic-goto-next-topic (n)
 259   "Go to the N'th next topic."
 260   (interactive "p")
 261   (let ((backward (< n 0))
 262         (n (abs n))
 263         (topic (gnus-current-topic)))
 264     (while (and (> n 0)
 265                 (setq topic
 266                       (if backward
 267                           (gnus-topic-previous-topic topic)
 268                         (gnus-topic-next-topic topic))))
 269       (gnus-topic-goto-topic topic)
 270       (setq n (1- n)))
 271     (when (/= 0 n)
 272       (gnus-message 7 "No more topics"))
 273     n))
 274
 275 (defun gnus-topic-previous-topic (topic)
 276   "Return the previous topic on the same level as TOPIC."
 277   (let ((top (cddr (gnus-topic-find-topology
 278                     (gnus-topic-parent-topic topic)))))
 279     (unless (equal topic (caaar top))
 280       (while (and top (not (equal (caaadr top) topic)))
 281         (setq top (cdr top)))
 282       (caaar top))))
 283
 284 (defun gnus-topic-parent-topic (topic &optional topology)
 285   "Return the parent of TOPIC."
 286   (unless topology
 287     (setq topology gnus-topic-topology))
 288   (let ((parent (car (pop topology)))
 289         result found)
 290     (while (and topology
 291                 (not (setq found (equal (caaar topology) topic)))
 292                 (not (setq result (gnus-topic-parent-topic
 293                                    topic (car topology)))))
 294       (setq topology (cdr topology)))
 295     (or result (and found parent))))
 296
 297 (defun gnus-topic-next-topic (topic &optional previous)
 298   "Return the next sibling of TOPIC."
 299   (let ((parentt (cddr (gnus-topic-find-topology
 300                         (gnus-topic-parent-topic topic))))
 301         prev)
 302     (while (and parentt
 303                 (not (equal (caaar parentt) topic)))
 304       (setq prev (caaar parentt)
 305             parentt (cdr parentt)))
 306     (if previous
 307         prev
 308       (caaadr parentt))))
 309
 310 (defun gnus-topic-forward-topic (num)
 311   "Go to the next topic on the same level as the current one."
 312   (let* ((topic (gnus-current-topic))
 313          (way (if (< num 0) 'gnus-topic-previous-topic
 314                 'gnus-topic-next-topic))
 315          (num (abs num)))
 316     (while (and (not (zerop num))
 317                 (setq topic (funcall way topic)))
 318       (when (gnus-topic-goto-topic topic)
 319         (decf num)))
 320     (unless (zerop num)
 321       (goto-char (point-max)))
 322     num))
 323
 324 (defun gnus-topic-find-topology (topic &optional topology level remove)
 325   "Return the topology of TOPIC."
 326   (unless topology
 327     (setq topology gnus-topic-topology)
 328     (setq level 0))
 329   (let ((top topology)
 330         result)
 331     (if (equal (caar topology) topic)
 332         (progn
 333           (when remove
 334             (delq topology remove))
 335           (cons level topology))
 336       (setq topology (cdr topology))
 337       (while (and topology
 338                   (not (setq result (gnus-topic-find-topology
 339                                      topic (car topology) (1+ level)
 340                                      (and remove top)))))
 341         (setq topology (cdr topology)))
 342       result)))
 343
 344 (defvar gnus-tmp-topics nil)
 345 (defun gnus-topic-list (&optional topology)
 346   "Return a list of all topics in the topology."
 347   (unless topology
 348     (setq topology gnus-topic-topology
 349           gnus-tmp-topics nil))
 350   (push (caar topology) gnus-tmp-topics)
 351   (mapc 'gnus-topic-list (cdr topology))
 352   gnus-tmp-topics)
 353
 354 ;;; Topic parameter jazz
 355
 356 (defun gnus-topic-parameters (topic)
 357   "Return the parameters for TOPIC."
 358   (let ((top (gnus-topic-find-topology topic)))
 359     (when top
 360       (nth 3 (cadr top)))))
 361
 362 (defun gnus-topic-set-parameters (topic parameters)
 363   "Set the topic parameters of TOPIC to PARAMETERS."
 364   (let ((top (gnus-topic-find-topology topic)))
 365     (unless top
 366       (error "No such topic: %s" topic))
 367     ;; We may have to extend if there is no parameters here
 368     ;; to begin with.
 369     (unless (nthcdr 2 (cadr top))
 370       (nconc (cadr top) (list nil)))
 371     (unless (nthcdr 3 (cadr top))
 372       (nconc (cadr top) (list nil)))
 373     (setcar (nthcdr 3 (cadr top)) parameters)
 374     (gnus-dribble-enter
 375      (format "(gnus-topic-set-parameters %S '%S)" topic parameters))))
 376
 377 (defun gnus-group-topic-parameters (group)
 378   "Compute the group parameters for GROUP in topic mode.
 379 Possibly inherit parameters from topics above GROUP."
 380   (let ((params-list (copy-sequence (gnus-group-get-parameter group))))
 381     (save-excursion
 382       (gnus-topic-hierarchical-parameters
 383        ;; First we try to go to the group within the group buffer and find the
 384        ;; topic for the group that way. This hopefully copes well with groups
 385        ;; that are in more than one topic. Failing that (i.e. when the group
 386        ;; isn't visible in the group buffer) we find a topic for the group via
 387        ;; gnus-group-topic.
 388        (or (and (gnus-group-goto-group group)
 389                 (gnus-current-topic))
 390            (gnus-group-topic group))
 391        params-list))))
 392
 393 (defun gnus-topic-hierarchical-parameters (topic &optional group-params-list)
 394   "Compute the topic parameters for TOPIC.
 395 Possibly inherit parameters from topics above TOPIC.
 396 If optional argument GROUP-PARAMS-LIST is non-nil, use it as the basis for
 397 inheritance."
 398   (let ((params-list
 399          ;; We probably have lots of nil elements here, so we remove them.
 400          ;; Probably faster than doing this "properly".
 401          (delq nil (cons group-params-list
 402                          (mapcar 'gnus-topic-parameters
 403                                  (gnus-current-topics topic)))))
 404         param out params)
 405     ;; Now we have all the parameters, so we go through them
 406     ;; and do inheritance in the obvious way.
 407     (let (posting-style)
 408       (while (setq params (pop params-list))
 409         (while (setq param (pop params))
 410           (when (atom param)
 411             (setq param (cons param t)))
 412           (cond ((eq (car param) 'posting-style)
 413                  (let ((param (cdr param))
 414                        elt)
 415                    (while (setq elt (pop param))
 416                      (unless (assoc (car elt) posting-style)
 417                        (push elt posting-style)))))
 418                 (t
 419                  (unless (assq (car param) out)
 420                    (push param out))))))
 421       (and posting-style (push (cons 'posting-style posting-style) out)))
 422     ;; Return the resulting parameter list.
 423     out))
 424
 425 ;;; General utility functions
 426
 427 (defun gnus-topic-enter-dribble ()
 428   (gnus-dribble-enter
 429    (format "(setq gnus-topic-topology '%S)" gnus-topic-topology)))
 430
 431 ;;; Generating group buffers
 432
 433 (defun gnus-group-prepare-topics (level &optional predicate lowest
 434                                         regexp list-topic topic-level)
 435   "List all newsgroups with unread articles of level LEVEL or lower.
 436 Use the `gnus-group-topics' to sort the groups.
 437 If PREDICTE is a function, list groups that the function returns non-nil;
 438 if it is t, list groups that have no unread articles.
 439 If LOWEST is non-nil, list all newsgroups of level LOWEST or higher."
 440   (set-buffer gnus-group-buffer)
 441   (let ((buffer-read-only nil)
 442         (lowest (or lowest 1))
 443         (not-in-list
 444          (and gnus-group-listed-groups
 445               (copy-sequence gnus-group-listed-groups))))
 446
 447     (gnus-update-format-specifications nil 'topic)
 448
 449     (when (or (not gnus-topic-alist)
 450               (not gnus-topology-checked-p))
 451       (gnus-topic-check-topology))
 452
 453     (unless list-topic
 454       (erase-buffer))
 455
 456     ;; List dead groups?
 457     (when (or gnus-group-listed-groups
 458               (and (>= level gnus-level-zombie)
 459                    (<= lowest gnus-level-zombie)))
 460       (gnus-group-prepare-flat-list-dead
 461        (setq gnus-zombie-list (sort gnus-zombie-list 'string<))
 462        gnus-level-zombie ?Z
 463        regexp))
 464
 465     (when (or gnus-group-listed-groups
 466                (and (>= level gnus-level-killed)
 467                     (<= lowest gnus-level-killed)))
 468       (gnus-group-prepare-flat-list-dead
 469        (setq gnus-killed-list (sort gnus-killed-list 'string<))
 470        gnus-level-killed ?K regexp)
 471       (when not-in-list
 472         (unless gnus-killed-hashtb
 473           (gnus-make-hashtable-from-killed))
 474         (gnus-group-prepare-flat-list-dead
 475          (gnus-remove-if (lambda (group)
 476                            (or (gnus-group-entry group)
 477                                (gnus-gethash group gnus-killed-hashtb)))
 478                          not-in-list)
 479          gnus-level-killed ?K regexp)))
 480
 481     ;; Use topics.
 482     (prog1
 483         (when (or (< lowest gnus-level-zombie)
 484                   gnus-group-listed-groups)
 485           (if list-topic
 486               (let ((top (gnus-topic-find-topology list-topic)))
 487                 (gnus-topic-prepare-topic (cdr top) (car top)
 488                                           (or topic-level level) predicate
 489                                           nil lowest regexp))
 490             (gnus-topic-prepare-topic gnus-topic-topology 0
 491                                       (or topic-level level) predicate
 492                                       nil lowest regexp)))
 493       (gnus-group-set-mode-line)
 494       (setq gnus-group-list-mode (cons level predicate))
 495       (gnus-run-hooks 'gnus-group-prepare-hook))))
 496
 497 (defun gnus-topic-prepare-topic (topicl level &optional list-level
 498                                         predicate silent
 499                                         lowest regexp)
 500   "Insert TOPIC into the group buffer.
 501 If SILENT, don't insert anything.  Return the number of unread
 502 articles in the topic and its subtopics."
 503   (let* ((type (pop topicl))
 504          (entries (gnus-topic-find-groups
 505                    (car type)
 506                    (if gnus-group-listed-groups
 507                        gnus-level-killed
 508                      list-level)
 509                    (or predicate gnus-group-listed-groups
 510                        (cdr (assq 'visible
 511                                   (gnus-topic-hierarchical-parameters
 512                                    (car type)))))
 513                    (if gnus-group-listed-groups 0 lowest)))
 514          (visiblep (and (eq (nth 1 type) 'visible) (not silent)))
 515          (gnus-group-indentation
 516           (make-string (* gnus-topic-indent-level level) ? ))
 517          (beg (progn (beginning-of-line) (point)))
 518          (topicl (reverse topicl))
 519          (all-entries entries)
 520          (point-max (point-max))
 521          (unread 0)
 522          (topic (car type))
 523          info entry end active tick)
 524     ;; Insert any sub-topics.
 525     (while topicl
 526       (incf unread
 527             (gnus-topic-prepare-topic
 528              (pop topicl) (1+ level) list-level predicate
 529              (not visiblep) lowest regexp)))
 530     (setq end (point))
 531     (goto-char beg)
 532     ;; Insert all the groups that belong in this topic.
 533     (while (setq entry (pop entries))
 534       (when (if (stringp entry)
 535                 (gnus-group-prepare-logic
 536                  entry
 537                  (and
 538                   (or (not gnus-group-listed-groups)
 539                       (if (< list-level gnus-level-zombie) nil
 540                         (let ((entry-level
 541                                (if (member entry gnus-zombie-list)
 542                                    gnus-level-zombie gnus-level-killed)))
 543                           (and (<= entry-level list-level)
 544                                (>= entry-level lowest)))))
 545                   (cond
 546                    ((stringp regexp)
 547                     (string-match regexp entry))
 548                    ((functionp regexp)
 549                     (funcall regexp entry))
 550                    ((null regexp) t)
 551                    (t nil))))
 552               (setq info (nth 2 entry))
 553               (gnus-group-prepare-logic
 554                (gnus-info-group info)
 555                (and (or (not gnus-group-listed-groups)
 556                         (let ((entry-level (gnus-info-level info)))
 557                           (and (<= entry-level list-level)
 558                                (>= entry-level lowest))))
 559                     (or (not (functionp predicate))
 560                         (funcall predicate info))
 561                     (or (not (stringp regexp))
 562                         (string-match regexp (gnus-info-group info))))))
 563         (when visiblep
 564           (if (stringp entry)
 565               ;; Dead groups.
 566               (gnus-group-insert-group-line
 567                entry (if (member entry gnus-zombie-list)
 568                          gnus-level-zombie gnus-level-killed)
 569                nil (- (1+ (cdr (setq active (gnus-active entry))))
 570                       (car active))
 571                nil)
 572             ;; Living groups.
 573             (when (setq info (nth 2 entry))
 574               (gnus-group-insert-group-line
 575                (gnus-info-group info)
 576                (gnus-info-level info) (gnus-info-marks info)
 577                (car entry) (gnus-info-method info)))))
 578         (when (and (listp entry)
 579                    (numberp (car entry)))
 580           (incf unread (car entry)))
 581         (when (listp entry)
 582           (setq tick t))))
 583     (goto-char beg)
 584     ;; Insert the topic line.
 585     (when (and (not silent)
 586                (or gnus-topic-display-empty-topics ;We want empty topics
 587                    (not (zerop unread)) ;Non-empty
 588                    tick                 ;Ticked articles
 589                    (/= point-max (point-max)))) ;Unactivated groups
 590       (gnus-extent-start-open (point))
 591       (gnus-topic-insert-topic-line
 592        (car type) visiblep
 593        (not (eq (nth 2 type) 'hidden))
 594        level all-entries unread))
 595     (gnus-topic-update-unreads (car type) unread)
 596     (when gnus-group-update-tool-bar
 597       (gnus-put-text-property beg end 'point-entered
 598                               'gnus-tool-bar-update)
 599       (gnus-put-text-property beg end 'point-left
 600                               'gnus-tool-bar-update))
 601     (goto-char end)
 602     unread))
 603
 604 (defun gnus-topic-remove-topic (&optional insert total-remove hide in-level)
 605   "Remove the current topic."
 606   (let ((topic (gnus-group-topic-name))
 607         (level (gnus-group-topic-level))
 608         (beg (progn (beginning-of-line) (point)))
 609         buffer-read-only)
 610     (when topic
 611       (while (and (zerop (forward-line 1))
 612                   (> (or (gnus-group-topic-level) (1+ level)) level)))
 613       (delete-region beg (point))
 614       ;; Do the change in this rather odd manner because it has been
 615       ;; reported that some topics share parts of some lists, for some
 616       ;; reason.  I have been unable to determine why this is the
 617       ;; case, but this hack seems to take care of things.
 618       (let ((data (cadr (gnus-topic-find-topology topic))))
 619         (setcdr data
 620                 (list (if insert 'visible 'invisible)
 621                       (caddr data)
 622                       (cadddr data))))
 623       (if total-remove
 624           (setq gnus-topic-alist
 625                 (delq (assoc topic gnus-topic-alist) gnus-topic-alist))
 626         (gnus-topic-insert-topic topic in-level)))))
 627
 628 (defun gnus-topic-insert-topic (topic &optional level)
 629   "Insert TOPIC."
 630   (gnus-group-prepare-topics
 631    (car gnus-group-list-mode) (cdr gnus-group-list-mode)
 632    nil nil topic level))
 633
 634 (defun gnus-topic-fold (&optional insert topic)
 635   "Remove/insert the current topic."
 636   (let ((topic (or topic (gnus-group-topic-name))))
 637     (when topic
 638       (save-excursion
 639         (if (not (gnus-group-active-topic-p))
 640             (gnus-topic-remove-topic
 641              (or insert (not (gnus-topic-visible-p))))
 642           (let ((gnus-topic-topology gnus-topic-active-topology)
 643                 (gnus-topic-alist gnus-topic-active-alist)
 644                 (gnus-group-list-mode (cons 5 t)))
 645             (gnus-topic-remove-topic
 646              (or insert (not (gnus-topic-visible-p))) nil nil 9)
 647             (gnus-topic-enter-dribble)))))))
 648
 649 (defun gnus-topic-insert-topic-line (name visiblep shownp level entries
 650                                           &optional unread)
 651   (let* ((visible (if visiblep "" "..."))
 652          (indentation (make-string (* gnus-topic-indent-level level) ? ))
 653          (total-number-of-articles unread)
 654          (number-of-groups (length entries))
 655          (active-topic (eq gnus-topic-alist gnus-topic-active-alist))
 656          gnus-tmp-header)
 657     (gnus-topic-update-unreads name unread)
 658     (beginning-of-line)
 659     ;; Insert the text.
 660     (if shownp
 661         (gnus-add-text-properties
 662          (point)
 663          (prog1 (1+ (point))
 664            (eval gnus-topic-line-format-spec))
 665          (list 'gnus-topic (intern name)
 666                'gnus-topic-level level
 667                'gnus-topic-unread unread
 668                'gnus-active active-topic
 669                'gnus-topic-visible visiblep)))))
 670
 671 (defun gnus-topic-update-unreads (topic unreads)
 672   (setq gnus-topic-unreads (delq (assoc topic gnus-topic-unreads)
 673                                  gnus-topic-unreads))
 674   (push (cons topic unreads) gnus-topic-unreads))
 675
 676 (defun gnus-topic-update-topics-containing-group (group)
 677   "Update all topics that have GROUP as a member."
 678   (when (and (eq major-mode 'gnus-group-mode)
 679              gnus-topic-mode)
 680     (save-excursion
 681       (let ((alist gnus-topic-alist))
 682         ;; This is probably not entirely correct.  If a topic
 683         ;; isn't shown, then it's not updated.  But the updating
 684         ;; should be performed in any case, since the topic's
 685         ;; parent should be updated.  Pfft.
 686         (while alist
 687           (when (and (member group (cdar alist))
 688                      (gnus-topic-goto-topic (caar alist)))
 689             (gnus-topic-update-topic-line (caar alist)))
 690           (pop alist))))))
 691
 692 (defun gnus-topic-update-topic ()
 693   "Update all parent topics to the current group."
 694   (when (and (eq major-mode 'gnus-group-mode)
 695              gnus-topic-mode)
 696     (let ((group (gnus-group-group-name))
 697           (m (point-marker))
 698           (buffer-read-only nil))
 699       (when (and group
 700                  (gnus-get-info group)
 701                  (gnus-topic-goto-topic (gnus-current-topic)))
 702         (gnus-topic-update-topic-line (gnus-group-topic-name))
 703         (goto-char m)
 704         (set-marker m nil)
 705         (gnus-group-position-point)))))
 706
 707 (defun gnus-topic-goto-missing-group (group)
 708   "Place point where GROUP is supposed to be inserted."
 709   (let* ((topic (gnus-group-topic group))
 710          (groups (cdr (assoc topic gnus-topic-alist)))
 711          (g (cdr (member group groups)))
 712          (unfound t)
 713          entry)
 714     ;; Try to jump to a visible group.
 715     (while (and g
 716                 (not (gnus-group-goto-group (car g) t)))
 717       (pop g))
 718     ;; It wasn't visible, so we try to see where to insert it.
 719     (when (not g)
 720       (setq g (cdr (member group (reverse groups))))
 721       (while (and g unfound)
 722         (when (gnus-group-goto-group (pop g) t)
 723           (forward-line 1)
 724           (setq unfound nil)))
 725       (when (and unfound
 726                  topic
 727                  (not (gnus-topic-goto-missing-topic topic)))
 728         (gnus-topic-display-missing-topic topic)))))
 729
 730 (defun gnus-topic-display-missing-topic (topic)
 731   "Insert topic lines recursively for missing topics."
 732   (let ((parent (gnus-topic-find-topology
 733                  (gnus-topic-parent-topic topic))))
 734     (when (and parent
 735                (not (gnus-topic-goto-missing-topic (caadr parent))))
 736       (gnus-topic-display-missing-topic (caadr parent))))
 737   (gnus-topic-goto-missing-topic topic)
 738   ;; Skip past all groups in the topic we're in.
 739   (while (gnus-group-group-name)
 740     (forward-line 1))
 741   (let* ((top (gnus-topic-find-topology topic))
 742          (children (cddr top))
 743          (type (cadr top))
 744          (unread 0)
 745          (entries (gnus-topic-find-groups
 746                    (car type) (car gnus-group-list-mode)
 747                    (cdr gnus-group-list-mode)))
 748         entry)
 749     (while children
 750       (incf unread (gnus-topic-unread (caar (pop children)))))
 751     (while (setq entry (pop entries))
 752       (when (numberp (car entry))
 753         (incf unread (car entry))))
 754     (gnus-topic-insert-topic-line
 755      topic t t (car (gnus-topic-find-topology topic)) nil unread)))
 756
 757 (defun gnus-topic-goto-missing-topic (topic)
 758   (if (gnus-topic-goto-topic topic)
 759       (forward-line 1)
 760     ;; Topic not displayed.
 761     (let* ((top (gnus-topic-find-topology
 762                  (gnus-topic-parent-topic topic)))
 763            (tp (reverse (cddr top))))
 764       (if (not top)
 765           (gnus-topic-insert-topic-line
 766            topic t t (car (gnus-topic-find-topology topic)) nil 0)
 767         (while (not (equal (caaar tp) topic))
 768           (setq tp (cdr tp)))
 769         (pop tp)
 770         (while (and tp
 771                     (not (gnus-topic-goto-topic (caaar tp))))
 772           (pop tp))
 773         (if tp
 774             (gnus-topic-forward-topic 1)
 775           (gnus-topic-goto-missing-topic (caadr top)))))
 776     nil))
 777
 778 (defun gnus-topic-update-topic-line (topic-name &optional reads)
 779   (let* ((top (gnus-topic-find-topology topic-name))
 780          (type (cadr top))
 781          (children (cddr top))
 782          (entries (gnus-topic-find-groups
 783                    (car type) (car gnus-group-list-mode)
 784                    (cdr gnus-group-list-mode)))
 785          (parent (gnus-topic-parent-topic topic-name))
 786          (all-entries entries)
 787          (unread 0)
 788          old-unread entry new-unread)
 789     (when (gnus-topic-goto-topic (car type))
 790       ;; Tally all the groups that belong in this topic.
 791       (if reads
 792           (setq unread (- (gnus-group-topic-unread) reads))
 793         (while children
 794           (incf unread (gnus-topic-unread (caar (pop children)))))
 795         (while (setq entry (pop entries))
 796           (when (numberp (car entry))
 797             (incf unread (car entry)))))
 798       (setq old-unread (gnus-group-topic-unread))
 799       ;; Insert the topic line.
 800       (gnus-topic-insert-topic-line
 801        (car type) (gnus-topic-visible-p)
 802        (not (eq (nth 2 type) 'hidden))
 803        (gnus-group-topic-level) all-entries unread)
 804       (gnus-delete-line)
 805       (forward-line -1)
 806       (setq new-unread (gnus-group-topic-unread)))
 807     (when parent
 808       (forward-line -1)
 809       (gnus-topic-update-topic-line
 810        parent
 811        (- (or old-unread 0) (or new-unread 0))))
 812     unread))
 813
 814 (defun gnus-topic-group-indentation ()
 815   (make-string
 816    (* gnus-topic-indent-level
 817       (or (save-excursion
 818             (forward-line -1)
 819             (gnus-topic-goto-topic (gnus-current-topic))
 820             (gnus-group-topic-level))
 821           0))
 822    ? ))
 823
 824 ;;; Initialization
 825
 826 (gnus-add-shutdown 'gnus-topic-close 'gnus)
 827
 828 (defun gnus-topic-close ()
 829   (setq gnus-topic-active-topology nil
 830         gnus-topic-active-alist nil
 831         gnus-topic-killed-topics nil
 832         gnus-topology-checked-p nil))
 833
 834 (defun gnus-topic-check-topology ()
 835   ;; The first time we set the topology to whatever we have
 836   ;; gotten here, which can be rather random.
 837   (unless gnus-topic-alist
 838     (gnus-topic-init-alist))
 839
 840   (setq gnus-topology-checked-p t)
 841   ;; Go through the topic alist and make sure that all topics
 842   ;; are in the topic topology.
 843   (let ((topics (gnus-topic-list))
 844         (alist gnus-topic-alist)
 845         changed)
 846     (while alist
 847       (unless (member (caar alist) topics)
 848         (nconc gnus-topic-topology
 849                (list (list (list (caar alist) 'visible))))
 850         (setq changed t))
 851       (setq alist (cdr alist)))
 852     (when changed
 853       (gnus-topic-enter-dribble))
 854     ;; Conversely, go through the topology and make sure that all
 855     ;; topologies have alists.
 856     (while topics
 857       (unless (assoc (car topics) gnus-topic-alist)
 858         (push (list (car topics)) gnus-topic-alist))
 859       (pop topics)))
 860   ;; Go through all living groups and make sure that
 861   ;; they belong to some topic.
 862   (let* ((tgroups (apply 'append (mapcar 'cdr gnus-topic-alist)))
 863          (entry (last (assoc (caar gnus-topic-topology) gnus-topic-alist)))
 864          (newsrc (cdr gnus-newsrc-alist))
 865          group)
 866     (while newsrc
 867       (unless (member (setq group (gnus-info-group (pop newsrc))) tgroups)
 868         (setcdr entry (list group))
 869         (setq entry (cdr entry)))))
 870   ;; Go through all topics and make sure they contain only living groups.
 871   (let ((alist gnus-topic-alist)
 872         topic)
 873     (while (setq topic (pop alist))
 874       (while (cdr topic)
 875         (if (and (cadr topic)
 876                  (gnus-group-entry (cadr topic)))
 877             (setq topic (cdr topic))
 878           (setcdr topic (cddr topic)))))))
 879
 880 (defun gnus-topic-init-alist ()
 881   "Initialize the topic structures."
 882   (setq gnus-topic-topology
 883         (cons (list "Gnus" 'visible)
 884               (mapcar (lambda (topic)
 885                         (list (list (car topic) 'visible)))
 886                       '(("misc")))))
 887   (setq gnus-topic-alist
 888         (list (cons "misc"
 889                     (mapcar (lambda (info) (gnus-info-group info))
 890                             (cdr gnus-newsrc-alist)))
 891               (list "Gnus")))
 892   (gnus-topic-enter-dribble))
 893
 894 ;;; Maintenance
 895
 896 (defun gnus-topic-clean-alist ()
 897   "Remove bogus groups from the topic alist."
 898   (let ((topic-alist gnus-topic-alist)
 899         result topic)
 900     (unless gnus-killed-hashtb
 901       (gnus-make-hashtable-from-killed))
 902     (while (setq topic (pop topic-alist))
 903       (let ((topic-name (pop topic))
 904             group filtered-topic)
 905         (while (setq group (pop topic))
 906           (when (and (or (gnus-active group)
 907                          (gnus-info-method (gnus-get-info group)))
 908                      (not (gnus-gethash group gnus-killed-hashtb)))
 909             (push group filtered-topic)))
 910         (push (cons topic-name (nreverse filtered-topic)) result)))
 911     (setq gnus-topic-alist (nreverse result))))
 912
 913 (defun gnus-topic-change-level (group level oldlevel &optional previous)
 914   "Run when changing levels to enter/remove groups from topics."
 915   (save-excursion
 916     (set-buffer gnus-group-buffer)
 917     (let ((buffer-read-only nil))
 918       (unless gnus-topic-inhibit-change-level
 919         (gnus-group-goto-group (or (car (nth 2 previous)) group))
 920         (when (and gnus-topic-mode
 921                    gnus-topic-alist
 922                    (not gnus-topic-inhibit-change-level))
 923           ;; Remove the group from the topics.
 924           (if (and (< oldlevel gnus-level-zombie)
 925                    (>= level gnus-level-zombie))
 926               (let ((alist gnus-topic-alist))
 927                 (while (gnus-group-goto-group group)
 928                   (gnus-delete-line))
 929                 (while alist
 930                   (when (member group (car alist))
 931                     (setcdr (car alist) (delete group (cdar alist))))
 932                   (pop alist)))
 933             ;; If the group is subscribed we enter it into the topics.
 934             (when (and (< level gnus-level-zombie)
 935                        (>= oldlevel gnus-level-zombie))
 936               (let* ((prev (gnus-group-group-name))
 937                      (gnus-topic-inhibit-change-level t)
 938                      (gnus-group-indentation
 939                       (make-string
 940                        (* gnus-topic-indent-level
 941                           (or (save-excursion
 942                                 (gnus-topic-goto-topic (gnus-current-topic))
 943                                 (gnus-group-topic-level))
 944                               0))
 945                        ? ))
 946                      (yanked (list group))
 947                      alist talist end)
 948                 ;; Then we enter the yanked groups into the topics
 949                 ;; they belong to.
 950                 (when (setq alist (assoc (save-excursion
 951                                            (forward-line -1)
 952                                            (or
 953                                             (gnus-current-topic)
 954                                             (caar gnus-topic-topology)))
 955                                          gnus-topic-alist))
 956                   (setq talist alist)
 957                   (when (stringp yanked)
 958                     (setq yanked (list yanked)))
 959                   (if (not prev)
 960                       (nconc alist yanked)
 961                     (if (not (cdr alist))
 962                         (setcdr alist (nconc yanked (cdr alist)))
 963                       (while (and (not end) (cdr alist))
 964                         (when (equal (cadr alist) prev)
 965                           (setcdr alist (nconc yanked (cdr alist)))
 966                           (setq end t))
 967                         (setq alist (cdr alist)))
 968                       (unless end
 969                         (nconc talist yanked))))))
 970               (gnus-topic-update-topic))))))))
 971
 972 (defun gnus-topic-goto-next-group (group props)
 973   "Go to group or the next group after group."
 974   (if (not group)
 975       (if (not (memq 'gnus-topic props))
 976           (goto-char (point-max))
 977         (gnus-topic-goto-topic (symbol-name (cadr (memq 'gnus-topic props)))))
 978     (if (gnus-group-goto-group group)
 979         t
 980       ;; The group is no longer visible.
 981       (let* ((list (assoc (gnus-group-topic group) gnus-topic-alist))
 982              (after (cdr (member group (cdr list)))))
 983         ;; First try to put point on a group after the current one.
 984         (while (and after
 985                     (not (gnus-group-goto-group (car after))))
 986           (setq after (cdr after)))
 987         ;; Then try to put point on a group before point.
 988         (unless after
 989           (setq after (cdr (member group (reverse (cdr list)))))
 990           (while (and after
 991                       (not (gnus-group-goto-group (car after))))
 992             (setq after (cdr after))))
 993         ;; Finally, just put point on the topic.
 994         (if (not (car list))
 995             (goto-char (point-min))
 996           (unless after
 997             (gnus-topic-goto-topic (car list))
 998             (setq after nil)))
 999         t))))
1000
1001 ;;; Topic-active functions
1002
1003 (defun gnus-topic-grok-active (&optional force)
1004   "Parse all active groups and create topic structures for them."
1005   ;; First we make sure that we have really read the active file.
1006   (when (or force
1007             (not gnus-topic-active-alist))
1008     (let (groups)
1009       ;; Get a list of all groups available.
1010       (mapatoms (lambda (g) (when (symbol-value g)
1011                               (push (symbol-name g) groups)))
1012                 gnus-active-hashtb)
1013       (setq groups (sort groups 'string<))
1014       ;; Init the variables.
1015       (setq gnus-topic-active-topology (list (list "" 'visible)))
1016       (setq gnus-topic-active-alist nil)
1017       ;; Descend the top-level hierarchy.
1018       (gnus-topic-grok-active-1 gnus-topic-active-topology groups)
1019       ;; Set the top-level topic names to something nice.
1020       (setcar (car gnus-topic-active-topology) "Gnus active")
1021       (setcar (car gnus-topic-active-alist) "Gnus active"))))
1022
1023 (defun gnus-topic-grok-active-1 (topology groups)
1024   (let* ((name (caar topology))
1025          (prefix (concat "^" (regexp-quote name)))
1026          tgroups ntopology group)
1027     (while (and groups
1028                 (string-match prefix (setq group (car groups))))
1029       (if (not (string-match "\\." group (match-end 0)))
1030           ;; There are no further hierarchies here, so we just
1031           ;; enter this group into the list belonging to this
1032           ;; topic.
1033           (push (pop groups) tgroups)
1034         ;; New sub-hierarchy, so we add it to the topology.
1035         (nconc topology (list (setq ntopology
1036                                     (list (list (substring
1037                                                  group 0 (match-end 0))
1038                                                 'invisible)))))
1039         ;; Descend the hierarchy.
1040         (setq groups (gnus-topic-grok-active-1 ntopology groups))))
1041     ;; We remove the trailing "." from the topic name.
1042     (setq name
1043           (if (string-match "\\.$" name)
1044               (substring name 0 (match-beginning 0))
1045             name))
1046     ;; Add this topic and its groups to the topic alist.
1047     (push (cons name (nreverse tgroups)) gnus-topic-active-alist)
1048     (setcar (car topology) name)
1049     ;; We return the rest of the groups that didn't belong
1050     ;; to this topic.
1051     groups))
1052
1053 ;;; Topic mode, commands and keymap.
1054
1055 (defvar gnus-topic-mode-map nil)
1056 (defvar gnus-group-topic-map nil)
1057
1058 (unless gnus-topic-mode-map
1059   (setq gnus-topic-mode-map (make-sparse-keymap))
1060
1061   ;; Override certain group mode keys.
1062   (gnus-define-keys gnus-topic-mode-map
1063     "=" gnus-topic-select-group
1064     "\r" gnus-topic-select-group
1065     " " gnus-topic-read-group
1066     "\C-c\C-x" gnus-topic-expire-articles
1067     "c" gnus-topic-catchup-articles
1068     "\C-k" gnus-topic-kill-group
1069     "\C-y" gnus-topic-yank-group
1070     "\M-g" gnus-topic-get-new-news-this-topic
1071     "AT" gnus-topic-list-active
1072     "Gp" gnus-topic-edit-parameters
1073     "#" gnus-topic-mark-topic
1074     "\M-#" gnus-topic-unmark-topic
1075     [tab] gnus-topic-indent
1076     [(meta tab)] gnus-topic-unindent
1077     "\C-i" gnus-topic-indent
1078     "\M-\C-i" gnus-topic-unindent
1079     gnus-mouse-2 gnus-mouse-pick-topic)
1080
1081   ;; Define a new submap.
1082   (gnus-define-keys (gnus-group-topic-map "T" gnus-group-mode-map)
1083     "#" gnus-topic-mark-topic
1084     "\M-#" gnus-topic-unmark-topic
1085     "n" gnus-topic-create-topic
1086     "m" gnus-topic-move-group
1087     "D" gnus-topic-remove-group
1088     "c" gnus-topic-copy-group
1089     "h" gnus-topic-hide-topic
1090     "s" gnus-topic-show-topic
1091     "j" gnus-topic-jump-to-topic
1092     "M" gnus-topic-move-matching
1093     "C" gnus-topic-copy-matching
1094     "\M-p" gnus-topic-goto-previous-topic
1095     "\M-n" gnus-topic-goto-next-topic
1096     "\C-i" gnus-topic-indent
1097     [tab] gnus-topic-indent
1098     "r" gnus-topic-rename
1099     "\177" gnus-topic-delete
1100     [delete] gnus-topic-delete
1101     "H" gnus-topic-toggle-display-empty-topics)
1102
1103   (gnus-define-keys (gnus-topic-sort-map "S" gnus-group-topic-map)
1104     "s" gnus-topic-sort-groups
1105     "a" gnus-topic-sort-groups-by-alphabet
1106     "u" gnus-topic-sort-groups-by-unread
1107     "l" gnus-topic-sort-groups-by-level
1108     "e" gnus-topic-sort-groups-by-server
1109     "v" gnus-topic-sort-groups-by-score
1110     "r" gnus-topic-sort-groups-by-rank
1111     "m" gnus-topic-sort-groups-by-method))
1112
1113 (defun gnus-topic-make-menu-bar ()
1114   (unless (boundp 'gnus-topic-menu)
1115     (easy-menu-define
1116      gnus-topic-menu gnus-topic-mode-map ""
1117      '("Topics"
1118        ["Toggle topics" gnus-topic-mode t]
1119        ("Groups"
1120         ["Copy..." gnus-topic-copy-group t]
1121         ["Move..." gnus-topic-move-group t]
1122         ["Remove" gnus-topic-remove-group t]
1123         ["Copy matching..." gnus-topic-copy-matching t]
1124         ["Move matching..." gnus-topic-move-matching t])
1125        ("Topics"
1126         ["Goto..." gnus-topic-jump-to-topic t]
1127         ["Show" gnus-topic-show-topic t]
1128         ["Hide" gnus-topic-hide-topic t]
1129         ["Delete" gnus-topic-delete t]
1130         ["Rename..." gnus-topic-rename t]
1131         ["Create..." gnus-topic-create-topic t]
1132         ["Mark" gnus-topic-mark-topic t]
1133         ["Indent" gnus-topic-indent t]
1134         ["Sort" gnus-topic-sort-topics t]
1135         ["Previous topic" gnus-topic-goto-previous-topic t]
1136         ["Next topic" gnus-topic-goto-next-topic t]
1137         ["Toggle hide empty" gnus-topic-toggle-display-empty-topics t]
1138         ["Edit parameters" gnus-topic-edit-parameters t])
1139        ["List active" gnus-topic-list-active t]))))
1140
1141 (defun gnus-topic-mode (&optional arg redisplay)
1142   "Minor mode for topicsifying Gnus group buffers."
1143   (interactive (list current-prefix-arg t))
1144   (when (eq major-mode 'gnus-group-mode)
1145     (make-local-variable 'gnus-topic-mode)
1146     (setq gnus-topic-mode
1147           (if (null arg) (not gnus-topic-mode)
1148             (> (prefix-numeric-value arg) 0)))
1149     ;; Infest Gnus with topics.
1150     (if (not gnus-topic-mode)
1151         (setq gnus-goto-missing-group-function nil)
1152       (when (gnus-visual-p 'topic-menu 'menu)
1153         (gnus-topic-make-menu-bar))
1154       (gnus-set-format 'topic t)
1155       (add-minor-mode 'gnus-topic-mode " Topic" gnus-topic-mode-map)
1156       (add-hook 'gnus-group-catchup-group-hook 'gnus-topic-update-topic)
1157       (set (make-local-variable 'gnus-group-prepare-function)
1158            'gnus-group-prepare-topics)
1159       (set (make-local-variable 'gnus-group-get-parameter-function)
1160            'gnus-group-topic-parameters)
1161       (set (make-local-variable 'gnus-group-goto-next-group-function)
1162            'gnus-topic-goto-next-group)
1163       (set (make-local-variable 'gnus-group-indentation-function)
1164            'gnus-topic-group-indentation)
1165       (set (make-local-variable 'gnus-group-update-group-function)
1166            'gnus-topic-update-topics-containing-group)
1167       (set (make-local-variable 'gnus-group-sort-alist-function)
1168            'gnus-group-sort-topic)
1169       (setq gnus-group-change-level-function 'gnus-topic-change-level)
1170       (setq gnus-goto-missing-group-function 'gnus-topic-goto-missing-group)
1171       (gnus-make-local-hook 'gnus-check-bogus-groups-hook)
1172       (add-hook 'gnus-check-bogus-groups-hook 'gnus-topic-clean-alist
1173                 nil 'local)
1174       (setq gnus-topology-checked-p nil)
1175       ;; We check the topology.
1176       (when gnus-newsrc-alist
1177         (gnus-topic-check-topology))
1178       (gnus-run-hooks 'gnus-topic-mode-hook))
1179     ;; Remove topic infestation.
1180     (unless gnus-topic-mode
1181       (remove-hook 'gnus-summary-exit-hook 'gnus-topic-update-topic)
1182       (setq gnus-group-change-level-function nil)
1183       (remove-hook 'gnus-check-bogus-groups-hook 'gnus-topic-clean-alist)
1184       (setq gnus-group-prepare-function 'gnus-group-prepare-flat)
1185       (setq gnus-group-sort-alist-function 'gnus-group-sort-flat))
1186     (when redisplay
1187       (gnus-group-list-groups))))
1188
1189 (defun gnus-topic-select-group (&optional all)
1190   "Select this newsgroup.
1191 No article is selected automatically.
1192 If the group is opened, just switch the summary buffer.
1193 If ALL is non-nil, already read articles become readable.
1194
1195 If ALL is a positive number, fetch this number of the latest
1196 articles in the group.  If ALL is a negative number, fetch this
1197 number of the earliest articles in the group.
1198
1199 If performed over a topic line, toggle folding the topic."
1200   (interactive "P")
1201   (when (and (eobp) (not (gnus-group-group-name)))
1202     (forward-line -1))
1203   (if (gnus-group-topic-p)
1204       (let ((gnus-group-list-mode
1205              (if all (cons (if (numberp all) all 7) t) gnus-group-list-mode)))
1206         (gnus-topic-fold all)
1207         (gnus-dribble-touch))
1208     (gnus-group-select-group all)))
1209
1210 (defun gnus-mouse-pick-topic (e)
1211   "Select the group or topic under the mouse pointer."
1212   (interactive "e")
1213   (mouse-set-point e)
1214   (gnus-topic-read-group nil))
1215
1216 (defun gnus-topic-expire-articles (topic)
1217   "Expire articles in this topic or group."
1218   (interactive (list (gnus-group-topic-name)))
1219   (if (not topic)
1220       (call-interactively 'gnus-group-expire-articles)
1221     (save-excursion
1222       (gnus-message 5 "Expiring groups in %s..." topic)
1223       (let ((gnus-group-marked
1224              (mapcar (lambda (entry) (car (nth 2 entry)))
1225                      (gnus-topic-find-groups topic gnus-level-killed t
1226                                              nil t))))
1227         (gnus-group-expire-articles nil))
1228       (gnus-message 5 "Expiring groups in %s...done" topic))))
1229
1230 (defun gnus-topic-catchup-articles (topic)
1231   "Catchup this topic or group.
1232 Also see `gnus-group-catchup'."
1233   (interactive (list (gnus-group-topic-name)))
1234   (if (not topic)
1235       (call-interactively 'gnus-group-catchup-current)
1236     (save-excursion
1237       (let* ((groups
1238              (mapcar (lambda (entry) (car (nth 2 entry)))
1239                      (gnus-topic-find-groups topic gnus-level-killed t
1240                                              nil t)))
1241              (buffer-read-only nil)
1242              (gnus-group-marked groups))
1243         (gnus-group-catchup-current)
1244         (mapcar 'gnus-topic-update-topics-containing-group groups)))))
1245
1246 (defun gnus-topic-read-group (&optional all no-article group)
1247   "Read news in this newsgroup.
1248 If the prefix argument ALL is non-nil, already read articles become
1249 readable.
1250
1251 If ALL is a positive number, fetch this number of the latest
1252 articles in the group.  If ALL is a negative number, fetch this
1253 number of the earliest articles in the group.
1254
1255 If the optional argument NO-ARTICLE is non-nil, no article will
1256 be auto-selected upon group entry.  If GROUP is non-nil, fetch
1257 that group.
1258
1259 If performed over a topic line, toggle folding the topic."
1260   (interactive "P")
1261   (if (gnus-group-topic-p)
1262       (let ((gnus-group-list-mode
1263              (if all (cons (if (numberp all) all 7) t) gnus-group-list-mode)))
1264         (gnus-topic-fold all))
1265     (gnus-group-read-group all no-article group)))
1266
1267 (defun gnus-topic-create-topic (topic parent &optional previous full-topic)
1268   "Create a new TOPIC under PARENT.
1269 When used interactively, PARENT will be the topic under point."
1270   (interactive
1271    (list
1272     (read-string "New topic: ")
1273     (gnus-current-topic)))
1274   ;; Check whether this topic already exists.
1275   (when (gnus-topic-find-topology topic)
1276     (error "Topic already exists"))
1277   (unless parent
1278     (setq parent (caar gnus-topic-topology)))
1279   (let ((top (cdr (gnus-topic-find-topology parent)))
1280         (full-topic (or full-topic (list (list topic 'visible nil nil)))))
1281     (unless top
1282       (error "No such parent topic: %s" parent))
1283     (if previous
1284         (progn
1285           (while (and (cdr top)
1286                       (not (equal (caaadr top) previous)))
1287             (setq top (cdr top)))
1288           (setcdr top (cons full-topic (cdr top))))
1289       (nconc top (list full-topic)))
1290     (unless (assoc topic gnus-topic-alist)
1291       (push (list topic) gnus-topic-alist)))
1292   (gnus-topic-enter-dribble)
1293   (gnus-group-list-groups)
1294   (gnus-topic-goto-topic topic))
1295
1296 ;; FIXME:
1297 ;;  1. When the marked groups are overlapped with the process
1298 ;;     region, the behavior of move or remove is not right.
1299 ;;  2. Can't process on several marked groups with a same name,
1300 ;;     because gnus-group-marked only keeps one copy.
1301
1302 (defun gnus-topic-move-group (n topic &optional copyp)
1303   "Move the next N groups to TOPIC.
1304 If COPYP, copy the groups instead."
1305   (interactive
1306    (list current-prefix-arg
1307          (gnus-completing-read "Move to topic" gnus-topic-alist nil t
1308                                'gnus-topic-history)))
1309   (let ((use-marked (and (not n) (not (gnus-region-active-p))
1310                          gnus-group-marked t))
1311         (groups (gnus-group-process-prefix n))
1312         (topicl (assoc topic gnus-topic-alist))
1313         (start-topic (gnus-group-topic-name))
1314         (start-group (progn (forward-line 1) (gnus-group-group-name)))
1315         entry)
1316     (if (and (not groups) (not copyp) start-topic)
1317         (gnus-topic-move start-topic topic)
1318       (dolist (g groups)
1319         (gnus-group-remove-mark g use-marked)
1320         (when (and
1321                (setq entry (assoc (gnus-current-topic) gnus-topic-alist))
1322                (not copyp))
1323           (setcdr entry (gnus-delete-first g (cdr entry))))
1324         (nconc topicl (list g)))
1325       (gnus-topic-enter-dribble)
1326       (if start-group
1327           (gnus-group-goto-group start-group)
1328         (gnus-topic-goto-topic start-topic))
1329       (gnus-group-list-groups))))
1330
1331 (defun gnus-topic-remove-group (&optional n)
1332   "Remove the current group from the topic."
1333   (interactive "P")
1334   (let ((use-marked (and (not n) (not (gnus-region-active-p))
1335                          gnus-group-marked t))
1336         (groups (gnus-group-process-prefix n)))
1337     (mapc
1338      (lambda (group)
1339        (gnus-group-remove-mark group use-marked)
1340        (let ((topicl (assoc (gnus-current-topic) gnus-topic-alist))
1341              (buffer-read-only nil))
1342          (when (and topicl group)
1343            (gnus-delete-line)
1344            (gnus-delete-first group topicl))
1345          (gnus-topic-update-topic)))
1346      groups)
1347     (gnus-topic-enter-dribble)
1348     (gnus-group-position-point)))
1349
1350 (defun gnus-topic-copy-group (n topic)
1351   "Copy the current group to a topic."
1352   (interactive
1353    (list current-prefix-arg
1354          (completing-read "Copy to topic: " gnus-topic-alist nil t)))
1355   (gnus-topic-move-group n topic t))
1356
1357 (defun gnus-topic-kill-group (&optional n discard)
1358   "Kill the next N groups."
1359   (interactive "P")
1360   (if (gnus-group-topic-p)
1361       (let ((topic (gnus-group-topic-name)))
1362         (push (cons
1363                (gnus-topic-find-topology topic)
1364                (assoc topic gnus-topic-alist))
1365               gnus-topic-killed-topics)
1366         (gnus-topic-remove-topic nil t)
1367         (gnus-topic-find-topology topic nil nil gnus-topic-topology)
1368         (gnus-topic-enter-dribble))
1369     (gnus-group-kill-group n discard)
1370     (if (not (gnus-group-topic-p))
1371         (gnus-topic-update-topic)
1372       ;; Move up one line so that we update the right topic.
1373       (forward-line -1)
1374       (gnus-topic-update-topic)
1375       (forward-line 1))))
1376
1377 (defun gnus-topic-yank-group (&optional arg)
1378   "Yank the last topic."
1379   (interactive "p")
1380   (if gnus-topic-killed-topics
1381       (let* ((previous
1382               (or (gnus-group-topic-name)
1383                   (gnus-topic-next-topic (gnus-current-topic))))
1384              (data (pop gnus-topic-killed-topics))
1385              (alist (cdr data))
1386              (item (cdar data)))
1387         (push alist gnus-topic-alist)
1388         (gnus-topic-create-topic
1389          (caar item) (gnus-topic-parent-topic previous) previous
1390          item)
1391         (gnus-topic-enter-dribble)
1392         (gnus-topic-goto-topic (caar item)))
1393     (let* ((prev (gnus-group-group-name))
1394            (gnus-topic-inhibit-change-level t)
1395            (gnus-group-indentation
1396             (make-string
1397              (* gnus-topic-indent-level
1398                 (or (save-excursion
1399                       (gnus-topic-goto-topic (gnus-current-topic))
1400                       (gnus-group-topic-level))
1401                     0))
1402              ? ))
1403            yanked alist)
1404       ;; We first yank the groups the normal way...
1405       (setq yanked (gnus-group-yank-group arg))
1406       ;; Then we enter the yanked groups into the topics they belong
1407       ;; to.
1408       (setq alist (assoc (save-excursion
1409                            (forward-line -1)
1410                            (gnus-current-topic))
1411                          gnus-topic-alist))
1412       (when (stringp yanked)
1413         (setq yanked (list yanked)))
1414       (if (not prev)
1415           (nconc alist yanked)
1416         (if (not (cdr alist))
1417             (setcdr alist (nconc yanked (cdr alist)))
1418           (while (cdr alist)
1419             (when (equal (cadr alist) prev)
1420               (setcdr alist (nconc yanked (cdr alist)))
1421               (setq alist nil))
1422             (setq alist (cdr alist))))))
1423     (gnus-topic-update-topic)))
1424
1425 (defun gnus-topic-hide-topic (&optional permanent)
1426   "Hide the current topic.
1427 If PERMANENT, make it stay hidden in subsequent sessions as well."
1428   (interactive "P")
1429   (when (gnus-current-topic)
1430     (gnus-topic-goto-topic (gnus-current-topic))
1431     (if permanent
1432         (setcar (cddr
1433                  (cadr
1434                   (gnus-topic-find-topology (gnus-current-topic))))
1435                 'hidden))
1436     (gnus-topic-remove-topic nil nil)))
1437
1438 (defun gnus-topic-show-topic (&optional permanent)
1439   "Show the hidden topic.
1440 If PERMANENT, make it stay shown in subsequent sessions as well."
1441   (interactive "P")
1442   (when (gnus-group-topic-p)
1443     (if (not permanent)
1444         (gnus-topic-remove-topic t nil)
1445       (let ((topic
1446              (gnus-topic-find-topology
1447               (completing-read "Show topic: " gnus-topic-alist nil t))))
1448         (setcar (cddr (cadr topic)) nil)
1449         (setcar (cdr (cadr topic)) 'visible)
1450         (gnus-group-list-groups)))))
1451
1452 (defun gnus-topic-mark-topic (topic &optional unmark non-recursive)
1453   "Mark all groups in the TOPIC with the process mark.
1454 If NON-RECURSIVE (which is the prefix) is t, don't mark its subtopics."
1455   (interactive (list (gnus-group-topic-name)
1456                      nil
1457                      (and current-prefix-arg t)))
1458   (if (not topic)
1459       (call-interactively 'gnus-group-mark-group)
1460     (save-excursion
1461       (let ((groups (gnus-topic-find-groups topic gnus-level-killed t nil
1462                                             (not non-recursive))))
1463         (while groups
1464           (funcall (if unmark 'gnus-group-remove-mark 'gnus-group-set-mark)
1465                    (gnus-info-group (nth 2 (pop groups)))))))))
1466
1467 (defun gnus-topic-unmark-topic (topic &optional dummy non-recursive)
1468   "Remove the process mark from all groups in the TOPIC.
1469 If NON-RECURSIVE (which is the prefix) is t, don't unmark its subtopics."
1470   (interactive (list (gnus-group-topic-name)
1471                      nil
1472                      (and current-prefix-arg t)))
1473   (if (not topic)
1474       (call-interactively 'gnus-group-unmark-group)
1475     (gnus-topic-mark-topic topic t non-recursive)))
1476
1477 (defun gnus-topic-get-new-news-this-topic (&optional n)
1478   "Check for new news in the current topic."
1479   (interactive "P")
1480   (if (not (gnus-group-topic-p))
1481       (gnus-group-get-new-news-this-group n)
1482     (let* ((topic (gnus-group-topic-name))
1483            (data (cadr (gnus-topic-find-topology topic))))
1484       (save-excursion
1485         (gnus-topic-mark-topic topic nil (and n t))
1486         (gnus-group-get-new-news-this-group))
1487       (gnus-topic-remove-topic (eq 'visible (cadr data))))))
1488
1489 (defun gnus-topic-move-matching (regexp topic &optional copyp)
1490   "Move all groups that match REGEXP to some topic."
1491   (interactive
1492    (let (topic)
1493      (nreverse
1494       (list
1495        (setq topic (completing-read "Move to topic: " gnus-topic-alist nil t))
1496        (read-string (format "Move to %s (regexp): " topic))))))
1497   (gnus-group-mark-regexp regexp)
1498   (gnus-topic-move-group nil topic copyp))
1499
1500 (defun gnus-topic-copy-matching (regexp topic &optional copyp)
1501   "Copy all groups that match REGEXP to some topic."
1502   (interactive
1503    (let (topic)
1504      (nreverse
1505       (list
1506        (setq topic (completing-read "Copy to topic: " gnus-topic-alist nil t))
1507        (read-string (format "Copy to %s (regexp): " topic))))))
1508   (gnus-topic-move-matching regexp topic t))
1509
1510 (defun gnus-topic-delete (topic)
1511   "Delete a topic."
1512   (interactive (list (gnus-group-topic-name)))
1513   (unless topic
1514     (error "No topic to be deleted"))
1515   (let ((entry (assoc topic gnus-topic-alist))
1516         (buffer-read-only nil))
1517     (when (cdr entry)
1518       (error "Topic not empty"))
1519     ;; Delete if visible.
1520     (when (gnus-topic-goto-topic topic)
1521       (gnus-delete-line))
1522     ;; Remove from alist.
1523     (setq gnus-topic-alist (delq entry gnus-topic-alist))
1524     ;; Remove from topology.
1525     (gnus-topic-find-topology topic nil nil 'delete)
1526     (gnus-dribble-touch)))
1527
1528 (defun gnus-topic-rename (old-name new-name)
1529   "Rename a topic."
1530   (interactive
1531    (let ((topic (gnus-current-topic)))
1532      (list topic
1533            (read-string (format "Rename %s to: " topic) topic))))
1534   ;; Check whether the new name exists.
1535   (when (gnus-topic-find-topology new-name)
1536     (error "Topic '%s' already exists" new-name))
1537   ;; "nil" is an invalid name, for reasons I'd rather not go
1538   ;; into here.  Trust me.
1539   (when (equal new-name "nil")
1540     (error "Invalid name: %s" nil))
1541   ;; Do the renaming.
1542   (let ((top (gnus-topic-find-topology old-name))
1543         (entry (assoc old-name gnus-topic-alist)))
1544     (when top
1545       (setcar (cadr top) new-name))
1546     (when entry
1547       (setcar entry new-name))
1548     (forward-line -1)
1549     (gnus-dribble-touch)
1550     (gnus-group-list-groups)
1551     (forward-line 1)))
1552
1553 (defun gnus-topic-indent (&optional unindent)
1554   "Indent a topic -- make it a sub-topic of the previous topic.
1555 If UNINDENT, remove an indentation."
1556   (interactive "P")
1557   (if unindent
1558       (gnus-topic-unindent)
1559     (let* ((topic (gnus-current-topic))
1560            (parent (gnus-topic-previous-topic topic))
1561            (buffer-read-only nil))
1562       (unless parent
1563         (error "Nothing to indent %s into" topic))
1564       (when topic
1565         (gnus-topic-goto-topic topic)
1566         (gnus-topic-kill-group)
1567         (push (cdar gnus-topic-killed-topics) gnus-topic-alist)
1568         (gnus-topic-create-topic
1569          topic parent nil (cdar (car gnus-topic-killed-topics)))
1570         (pop gnus-topic-killed-topics)
1571         (or (gnus-topic-goto-topic topic)
1572             (gnus-topic-goto-topic parent))))))
1573
1574 (defun gnus-topic-unindent ()
1575   "Unindent a topic."
1576   (interactive)
1577   (let* ((topic (gnus-current-topic))
1578          (parent (gnus-topic-parent-topic topic))
1579          (grandparent (gnus-topic-parent-topic parent)))
1580     (unless grandparent
1581       (error "Nothing to indent %s into" topic))
1582     (when topic
1583       (gnus-topic-goto-topic topic)
1584       (gnus-topic-kill-group)
1585       (push (cdar gnus-topic-killed-topics) gnus-topic-alist)
1586       (gnus-topic-create-topic
1587        topic grandparent (gnus-topic-next-topic parent)
1588        (cdar (car gnus-topic-killed-topics)))
1589       (pop gnus-topic-killed-topics)
1590       (gnus-topic-goto-topic topic))))
1591
1592 (defun gnus-topic-list-active (&optional force)
1593   "List all groups that Gnus knows about in a topicsified fashion.
1594 If FORCE, always re-read the active file."
1595   (interactive "P")
1596   (when force
1597     (gnus-get-killed-groups))
1598   (gnus-topic-grok-active force)
1599   (let ((gnus-topic-topology gnus-topic-active-topology)
1600         (gnus-topic-alist gnus-topic-active-alist)
1601         gnus-killed-list gnus-zombie-list)
1602     (gnus-group-list-groups gnus-level-killed nil 1)))
1603
1604 (defun gnus-topic-toggle-display-empty-topics ()
1605   "Show/hide topics that have no unread articles."
1606   (interactive)
1607   (setq gnus-topic-display-empty-topics
1608         (not gnus-topic-display-empty-topics))
1609   (gnus-group-list-groups)
1610   (message "%s empty topics"
1611            (if gnus-topic-display-empty-topics
1612                "Showing" "Hiding")))
1613
1614 ;;; Topic sorting functions
1615
1616 (defun gnus-topic-edit-parameters (group)
1617   "Edit the group parameters of GROUP.
1618 If performed on a topic, edit the topic parameters instead."
1619   (interactive (list (gnus-group-group-name)))
1620   (if group
1621       (gnus-group-edit-group-parameters group)
1622     (if (not (gnus-group-topic-p))
1623         (error "Nothing to edit on the current line")
1624       (let ((topic (gnus-group-topic-name)))
1625         (gnus-edit-form
1626          (gnus-topic-parameters topic)
1627          (format "Editing the topic parameters for `%s'."
1628                  (or group topic))
1629          `(lambda (form)
1630             (gnus-topic-set-parameters ,topic form)))))))
1631
1632 (defun gnus-group-sort-topic (func reverse)
1633   "Sort groups in the topics according to FUNC and REVERSE."
1634   (let ((alist gnus-topic-alist))
1635     (while alist
1636       ;; !!!Sometimes nil elements sneak into the alist,
1637       ;; for some reason or other.
1638       (setcar alist (delq nil (car alist)))
1639       (setcar alist (delete "dummy.group" (car alist)))
1640       (gnus-topic-sort-topic (pop alist) func reverse))))
1641
1642 (defun gnus-topic-sort-topic (topic func reverse)
1643   ;; Each topic only lists the name of the group, while
1644   ;; the sort predicates expect group infos as inputs.
1645   ;; So we first transform the group names into infos,
1646   ;; then sort, and then transform back into group names.
1647   (setcdr
1648    topic
1649    (mapcar
1650     (lambda (info) (gnus-info-group info))
1651     (sort
1652      (mapcar
1653       (lambda (group) (gnus-get-info group))
1654       (cdr topic))
1655      func)))
1656   ;; Do the reversal, if necessary.
1657   (when reverse
1658     (setcdr topic (nreverse (cdr topic)))))
1659
1660 (defun gnus-topic-sort-groups (func &optional reverse)
1661   "Sort the current topic according to FUNC.
1662 If REVERSE, reverse the sorting order."
1663   (interactive (list gnus-group-sort-function current-prefix-arg))
1664   (let ((topic (assoc (gnus-current-topic) gnus-topic-alist)))
1665     (gnus-topic-sort-topic
1666      topic (gnus-make-sort-function func) reverse)
1667     (gnus-group-list-groups)))
1668
1669 (defun gnus-topic-sort-groups-by-alphabet (&optional reverse)
1670   "Sort the current topic alphabetically by group name.
1671 If REVERSE, sort in reverse order."
1672   (interactive "P")
1673   (gnus-topic-sort-groups 'gnus-group-sort-by-alphabet reverse))
1674
1675 (defun gnus-topic-sort-groups-by-unread (&optional reverse)
1676   "Sort the current topic by number of unread articles.
1677 If REVERSE, sort in reverse order."
1678   (interactive "P")
1679   (gnus-topic-sort-groups 'gnus-group-sort-by-unread reverse))
1680
1681 (defun gnus-topic-sort-groups-by-level (&optional reverse)
1682   "Sort the current topic by group level.
1683 If REVERSE, sort in reverse order."
1684   (interactive "P")
1685   (gnus-topic-sort-groups 'gnus-group-sort-by-level reverse))
1686
1687 (defun gnus-topic-sort-groups-by-score (&optional reverse)
1688   "Sort the current topic by group score.
1689 If REVERSE, sort in reverse order."
1690   (interactive "P")
1691   (gnus-topic-sort-groups 'gnus-group-sort-by-score reverse))
1692
1693 (defun gnus-topic-sort-groups-by-rank (&optional reverse)
1694   "Sort the current topic by group rank.
1695 If REVERSE, sort in reverse order."
1696   (interactive "P")
1697   (gnus-topic-sort-groups 'gnus-group-sort-by-rank reverse))
1698
1699 (defun gnus-topic-sort-groups-by-method (&optional reverse)
1700   "Sort the current topic alphabetically by backend name.
1701 If REVERSE, sort in reverse order."
1702   (interactive "P")
1703   (gnus-topic-sort-groups 'gnus-group-sort-by-method reverse))
1704
1705 (defun gnus-topic-sort-groups-by-server (&optional reverse)
1706   "Sort the current topic alphabetically by server name.
1707 If REVERSE, sort in reverse order."
1708   (interactive "P")
1709   (gnus-topic-sort-groups 'gnus-group-sort-by-server reverse))
1710
1711 (defun gnus-topic-sort-topics-1 (top reverse)
1712   (if (cdr top)
1713       (let ((subtop
1714              (mapcar (gnus-byte-compile
1715                       `(lambda (top)
1716                          (gnus-topic-sort-topics-1 top ,reverse)))
1717                      (sort (cdr top)
1718                            (lambda (t1 t2)
1719                              (string-lessp (caar t1) (caar t2)))))))
1720         (setcdr top (if reverse (reverse subtop) subtop))))
1721   top)
1722
1723 (defun gnus-topic-sort-topics (&optional topic reverse)
1724   "Sort topics in TOPIC alphabetically by topic name.
1725 If REVERSE, reverse the sorting order."
1726   (interactive
1727    (list (completing-read "Sort topics in : " gnus-topic-alist nil t
1728                           (gnus-current-topic))
1729          current-prefix-arg))
1730   (let ((topic-topology (or (and topic (cdr (gnus-topic-find-topology topic)))
1731                             gnus-topic-topology)))
1732     (gnus-topic-sort-topics-1 topic-topology reverse)
1733     (gnus-topic-enter-dribble)
1734     (gnus-group-list-groups)
1735     (gnus-topic-goto-topic topic)))
1736
1737 (defun gnus-topic-move (current to)
1738   "Move the CURRENT topic to TO."
1739   (interactive
1740    (list
1741     (gnus-group-topic-name)
1742     (completing-read "Move to topic: " gnus-topic-alist nil t)))
1743   (unless (and current to)
1744     (error "Can't find topic"))
1745   (let ((current-top (cdr (gnus-topic-find-topology current)))
1746         (to-top (cdr (gnus-topic-find-topology to))))
1747     (unless current-top
1748       (error "Can't find topic `%s'" current))
1749     (unless to-top
1750       (error "Can't find topic `%s'" to))
1751     (if (gnus-topic-find-topology to current-top 0);; Don't care the level
1752         (error "Can't move `%s' to its sub-level" current))
1753     (gnus-topic-find-topology current nil nil 'delete)
1754     (setcdr (last to-top) (list current-top))
1755     (gnus-topic-enter-dribble)
1756     (gnus-group-list-groups)
1757     (gnus-topic-goto-topic current)))
1758
1759 (defun gnus-subscribe-topics (newsgroup)
1760   (catch 'end
1761     (let (match gnus-group-change-level-function)
1762       (dolist (topic (gnus-topic-list))
1763         (when (and (setq match (cdr (assq 'subscribe
1764                                           (gnus-topic-parameters topic))))
1765                    (string-match match newsgroup))
1766           ;; Just subscribe the group.
1767           (gnus-subscribe-alphabetically newsgroup)
1768           ;; Add the group to the topic.
1769           (nconc (assoc topic gnus-topic-alist) (list newsgroup))
1770           ;; if this topic specifies a default level, use it
1771           (let ((subscribe-level (cdr (assq 'subscribe-level
1772                                             (gnus-topic-parameters topic)))))
1773             (when subscribe-level
1774                 (gnus-group-change-level newsgroup subscribe-level
1775                                          gnus-level-default-subscribed)))
1776           (throw 'end t)))
1777       nil)))
1778
1779 (provide 'gnus-topic)
1780
1781 ;; arch-tag: bf176856-f30c-40f0-ae77-e41529a1134c
1782 ;;; gnus-topic.el ends here