lisp/gnus/gnus-topic.el

   1 ;;; gnus-topic.el --- a folding minor mode for Gnus group buffers
   2
   3 ;; Copyright (C) 1995-2018 Free Software Foundation, Inc.
   4
   5 ;; Author: Ilja Weis <kult@uni-paderborn.de>
   6 ;;      Lars Magne Ingebrigtsen <larsi@gnus.org>
   7 ;; Keywords: news
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;;; Code:
  27
  28 (eval-when-compile (require 'cl))
  29
  30 (require 'gnus)
  31 (require 'gnus-group)
  32 (require 'gnus-start)
  33 (require 'gnus-util)
  34
  35 (defgroup gnus-topic nil
  36   "Group topics."
  37   :group 'gnus-group)
  38
  39 (defvar gnus-topic-mode nil
  40   "Minor mode for Gnus group buffers.")
  41
  42 (defcustom gnus-topic-mode-hook nil
  43   "Hook run in topic mode buffers."
  44   :type 'hook
  45   :group 'gnus-topic)
  46
  47 (defcustom gnus-topic-line-format "%i[ %(%{%n%}%) -- %A ]%v\n"
  48   "Format of topic lines.
  49 It works along the same lines as a normal formatting string,
  50 with some simple extensions.
  51
  52 %i  Indentation based on topic level.
  53 %n  Topic name.
  54 %v  Nothing if the topic is visible, \"...\" otherwise.
  55 %g  Number of groups in the topic.
  56 %a  Number of unread articles in the groups in the topic.
  57 %A  Number of unread articles in the groups in the topic and its subtopics.
  58
  59 General format specifiers can also be used.
  60 See Info node `(gnus)Formatting Variables'."
  61   :link '(custom-manual "(gnus)Formatting Variables")
  62   :type 'string
  63   :group 'gnus-topic)
  64
  65 (defcustom gnus-topic-indent-level 2
  66   "How much each subtopic should be indented."
  67   :type 'integer
  68   :group 'gnus-topic)
  69
  70 (defcustom gnus-topic-display-empty-topics t
  71   "If non-nil, display the topic lines even of topics that have no unread articles."
  72   :type 'boolean
  73   :group 'gnus-topic)
  74
  75 ;; Internal variables.
  76
  77 (defvar gnus-topic-active-topology nil)
  78 (defvar gnus-topic-active-alist nil)
  79 (defvar gnus-topic-unreads nil)
  80
  81 (defvar gnus-topology-checked-p nil
  82   "Whether the topology has been checked in this session.")
  83
  84 (defvar gnus-topic-killed-topics nil)
  85 (defvar gnus-topic-inhibit-change-level nil)
  86
  87 (defconst gnus-topic-line-format-alist
  88   `((?n name ?s)
  89     (?v visible ?s)
  90     (?i indentation ?s)
  91     (?g number-of-groups ?d)
  92     (?a (gnus-topic-articles-in-topic entries) ?d)
  93     (?A total-number-of-articles ?d)
  94     (?l level ?d)))
  95
  96 (defvar gnus-topic-line-format-spec nil)
  97
  98 ;;; Utility functions
  99
 100 (defun gnus-group-topic-name ()
 101   "The name of the topic on the current line."
 102   (let ((topic (get-text-property (point-at-bol) 'gnus-topic)))
 103     (and topic (symbol-name topic))))
 104
 105 (defun gnus-group-topic-level ()
 106   "The level of the topic on the current line."
 107   (get-text-property (point-at-bol) 'gnus-topic-level))
 108
 109 (defun gnus-group-topic-unread ()
 110   "The number of unread articles in topic on the current line."
 111   (get-text-property (point-at-bol) 'gnus-topic-unread))
 112
 113 (defun gnus-topic-unread (topic)
 114   "Return the number of unread articles in TOPIC."
 115   (or (cdr (assoc topic gnus-topic-unreads))
 116       0))
 117
 118 (defun gnus-group-topic-p ()
 119   "Return non-nil if the current line is a topic."
 120   (gnus-group-topic-name))
 121
 122 (defun gnus-topic-visible-p ()
 123   "Return non-nil if the current topic is visible."
 124   (get-text-property (point-at-bol) 'gnus-topic-visible))
 125
 126 (defun gnus-topic-articles-in-topic (entries)
 127   (let ((total 0)
 128         number)
 129     (while entries
 130       (when (numberp (setq number (car (pop entries))))
 131         (incf total number)))
 132     total))
 133
 134 (defun gnus-group-topic (group)
 135   "Return the topic GROUP is a member of."
 136   (let ((alist gnus-topic-alist)
 137         out)
 138     (while alist
 139       (when (member group (cdar alist))
 140         (setq out (caar alist)
 141               alist nil))
 142       (setq alist (cdr alist)))
 143     out))
 144
 145 (defun gnus-topic-goto-topic (topic)
 146   (when topic
 147     (gnus-goto-char (text-property-any (point-min) (point-max)
 148                                        'gnus-topic (intern topic)))))
 149
 150 (defun gnus-topic-jump-to-topic (topic)
 151   "Go to TOPIC."
 152   (interactive
 153    (list (gnus-completing-read "Go to topic" (gnus-topic-list) t)))
 154   (let ((inhibit-read-only t))
 155     (dolist (topic (gnus-current-topics topic))
 156       (unless (gnus-topic-goto-topic topic)
 157         (gnus-topic-goto-missing-topic topic)
 158         (gnus-topic-display-missing-topic topic))))
 159   (gnus-topic-goto-topic topic))
 160
 161 (defun gnus-current-topic ()
 162   "Return the name of the current topic."
 163   (let ((result
 164          (or (get-text-property (point) 'gnus-topic)
 165              (save-excursion
 166                (and (gnus-goto-char (previous-single-property-change
 167                                      (point) 'gnus-topic))
 168                     (get-text-property (max (1- (point)) (point-min))
 169                                        'gnus-topic))))))
 170     (when result
 171       (symbol-name result))))
 172
 173 (defun gnus-current-topics (&optional topic)
 174   "Return a list of all current topics, lowest in hierarchy first.
 175 If TOPIC, start with that topic."
 176   (let ((topic (or topic (gnus-current-topic)))
 177         topics)
 178     (while topic
 179       (push topic topics)
 180       (setq topic (gnus-topic-parent-topic topic)))
 181     (nreverse topics)))
 182
 183 (defun gnus-group-active-topic-p ()
 184   "Say whether the current topic comes from the active topics."
 185   (get-text-property (point-at-bol) 'gnus-active))
 186
 187 (defun gnus-topic-find-groups (topic &optional level all lowest recursive)
 188   "Return entries for all visible groups in TOPIC.
 189 If RECURSIVE is t, return groups in its subtopics too."
 190   (let ((groups (cdr (assoc topic gnus-topic-alist)))
 191         info clevel unread group params visible-groups entry active)
 192     (setq lowest (or lowest 1))
 193     (setq level (or level gnus-level-unsubscribed))
 194     ;; We go through the newsrc to look for matches.
 195     (while groups
 196       (when (setq group (pop groups))
 197         (setq entry (gnus-group-entry group)
 198               info (nth 2 entry)
 199               params (gnus-info-params info)
 200               active (gnus-active group)
 201               unread (or (car entry)
 202                          (and (not (equal group "dummy.group"))
 203                               active
 204                               (- (1+ (cdr active)) (car active))))
 205               clevel (or (gnus-info-level info)
 206                          (if (member group gnus-zombie-list)
 207                              gnus-level-zombie gnus-level-killed))))
 208       (and
 209        info                             ; nil means that the group is dead.
 210        (<= clevel level)
 211        (>= clevel lowest)               ; Is inside the level we want.
 212        (or all
 213            (if (or (eq unread t)
 214                    (eq unread nil))
 215                gnus-group-list-inactive-groups
 216              (> unread 0))
 217            (and gnus-list-groups-with-ticked-articles
 218                 (cdr (assq 'tick (gnus-info-marks info))))
 219            ;; Has right readedness.
 220            ;; Check for permanent visibility.
 221            (and gnus-permanently-visible-groups
 222                 (string-match gnus-permanently-visible-groups group))
 223            ;; Marked groups are always visible.
 224            (member group gnus-group-marked)
 225            (memq 'visible params)
 226            (cdr (assq 'visible params)))
 227        ;; Add this group to the list of visible groups.
 228        (push (or entry group) visible-groups)))
 229     (setq visible-groups (nreverse visible-groups))
 230     (when recursive
 231       (if (eq recursive t)
 232           (setq recursive (cdr (gnus-topic-find-topology topic))))
 233       (dolist (topic-topology (cdr recursive))
 234         (setq visible-groups
 235               (nconc visible-groups
 236                      (gnus-topic-find-groups
 237                       (caar topic-topology)
 238                       level all lowest topic-topology)))))
 239     visible-groups))
 240
 241 (defun gnus-topic-goto-previous-topic (n)
 242   "Go to the N'th previous topic."
 243   (interactive "p")
 244   (gnus-topic-goto-next-topic (- n)))
 245
 246 (defun gnus-topic-goto-next-topic (n)
 247   "Go to the N'th next topic."
 248   (interactive "p")
 249   (let ((backward (< n 0))
 250         (n (abs n))
 251         (topic (gnus-current-topic)))
 252     (while (and (> n 0)
 253                 (setq topic
 254                       (if backward
 255                           (gnus-topic-previous-topic topic)
 256                         (gnus-topic-next-topic topic))))
 257       (gnus-topic-goto-topic topic)
 258       (setq n (1- n)))
 259     (when (/= 0 n)
 260       (gnus-message 7 "No more topics"))
 261     n))
 262
 263 (defun gnus-topic-previous-topic (topic)
 264   "Return the previous topic on the same level as TOPIC."
 265   (let ((top (cddr (gnus-topic-find-topology
 266                     (gnus-topic-parent-topic topic)))))
 267     (unless (equal topic (caaar top))
 268       (while (and top (not (equal (caaadr top) topic)))
 269         (setq top (cdr top)))
 270       (caaar top))))
 271
 272 (defun gnus-topic-parent-topic (topic &optional topology)
 273   "Return the parent of TOPIC."
 274   (unless topology
 275     (setq topology gnus-topic-topology))
 276   (let ((parent (car (pop topology)))
 277         result found)
 278     (while (and topology
 279                 (not (setq found (equal (caaar topology) topic)))
 280                 (not (setq result (gnus-topic-parent-topic
 281                                    topic (car topology)))))
 282       (setq topology (cdr topology)))
 283     (or result (and found parent))))
 284
 285 (defun gnus-topic-next-topic (topic &optional previous)
 286   "Return the next sibling of TOPIC."
 287   (let ((parentt (cddr (gnus-topic-find-topology
 288                         (gnus-topic-parent-topic topic))))
 289         prev)
 290     (while (and parentt
 291                 (not (equal (caaar parentt) topic)))
 292       (setq prev (caaar parentt)
 293             parentt (cdr parentt)))
 294     (if previous
 295         prev
 296       (caaadr parentt))))
 297
 298 (defun gnus-topic-forward-topic (num)
 299   "Go to the next topic on the same level as the current one."
 300   (let* ((topic (gnus-current-topic))
 301          (way (if (< num 0) 'gnus-topic-previous-topic
 302                 'gnus-topic-next-topic))
 303          (num (abs num)))
 304     (while (and (not (zerop num))
 305                 (setq topic (funcall way topic)))
 306       (when (gnus-topic-goto-topic topic)
 307         (decf num)))
 308     (unless (zerop num)
 309       (goto-char (point-max)))
 310     num))
 311
 312 (defun gnus-topic-find-topology (topic &optional topology level remove)
 313   "Return the topology of TOPIC."
 314   (unless topology
 315     (setq topology gnus-topic-topology)
 316     (setq level 0))
 317   (let ((top topology)
 318         result)
 319     (if (equal (caar topology) topic)
 320         (progn
 321           (when remove
 322             (delq topology remove))
 323           (cons level topology))
 324       (setq topology (cdr topology))
 325       (while (and topology
 326                   (not (setq result (gnus-topic-find-topology
 327                                      topic (car topology) (1+ level)
 328                                      (and remove top)))))
 329         (setq topology (cdr topology)))
 330       result)))
 331
 332 (defvar gnus-tmp-topics nil)
 333 (defun gnus-topic-list (&optional topology)
 334   "Return a list of all topics in the topology."
 335   (unless topology
 336     (setq topology gnus-topic-topology
 337           gnus-tmp-topics nil))
 338   (push (caar topology) gnus-tmp-topics)
 339   (mapc 'gnus-topic-list (cdr topology))
 340   gnus-tmp-topics)
 341
 342 ;;; Topic parameter jazz
 343
 344 (defun gnus-topic-parameters (topic)
 345   "Return the parameters for TOPIC."
 346   (let ((top (gnus-topic-find-topology topic)))
 347     (when top
 348       (nth 3 (cadr top)))))
 349
 350 (defun gnus-topic-set-parameters (topic parameters)
 351   "Set the topic parameters of TOPIC to PARAMETERS."
 352   (let ((top (gnus-topic-find-topology topic)))
 353     (unless top
 354       (error "No such topic: %s" topic))
 355     ;; We may have to extend if there is no parameters here
 356     ;; to begin with.
 357     (unless (nthcdr 2 (cadr top))
 358       (nconc (cadr top) (list nil)))
 359     (unless (nthcdr 3 (cadr top))
 360       (nconc (cadr top) (list nil)))
 361     (setcar (nthcdr 3 (cadr top)) parameters)
 362     (gnus-dribble-enter
 363      (format "(gnus-topic-set-parameters %S '%S)" topic parameters))))
 364
 365 (defun gnus-group-topic-parameters (group)
 366   "Compute the group parameters for GROUP in topic mode.
 367 Possibly inherit parameters from topics above GROUP."
 368   (let ((params-list (copy-sequence (gnus-group-get-parameter group))))
 369     (save-excursion
 370       (gnus-topic-hierarchical-parameters
 371        ;; First we try to go to the group within the group buffer and find the
 372        ;; topic for the group that way. This hopefully copes well with groups
 373        ;; that are in more than one topic. Failing that (i.e. when the group
 374        ;; isn't visible in the group buffer) we find a topic for the group via
 375        ;; gnus-group-topic.
 376        (or (and (gnus-group-goto-group group)
 377                 (gnus-current-topic))
 378            (gnus-group-topic group))
 379        params-list))))
 380
 381 (defun gnus-topic-hierarchical-parameters (topic &optional group-params-list)
 382   "Compute the topic parameters for TOPIC.
 383 Possibly inherit parameters from topics above TOPIC.
 384 If optional argument GROUP-PARAMS-LIST is non-nil, use it as the basis for
 385 inheritance."
 386   (let ((params-list
 387          ;; We probably have lots of nil elements here, so we remove them.
 388          ;; Probably faster than doing this "properly".
 389          (delq nil (cons group-params-list
 390                          (mapcar 'gnus-topic-parameters
 391                                  (gnus-current-topics topic)))))
 392         param out params)
 393     ;; Now we have all the parameters, so we go through them
 394     ;; and do inheritance in the obvious way.
 395     (let (posting-style)
 396       (while (setq params (pop params-list))
 397         (while (setq param (pop params))
 398           (when (atom param)
 399             (setq param (cons param t)))
 400           (cond ((eq (car param) 'posting-style)
 401                  (let ((param (cdr param))
 402                        elt)
 403                    (while (setq elt (pop param))
 404                      (unless (assoc (car elt) posting-style)
 405                        (push elt posting-style)))))
 406                 (t
 407                  (unless (assq (car param) out)
 408                    (push param out))))))
 409       (and posting-style (push (cons 'posting-style posting-style) out)))
 410     ;; Return the resulting parameter list.
 411     out))
 412
 413 ;;; General utility functions
 414
 415 (defun gnus-topic-enter-dribble ()
 416   (gnus-dribble-enter
 417    (format "(setq gnus-topic-topology '%S)" gnus-topic-topology)))
 418
 419 ;;; Generating group buffers
 420
 421 (defun gnus-group-prepare-topics (level &optional predicate lowest
 422                                         regexp list-topic topic-level)
 423   "List all newsgroups with unread articles of level LEVEL or lower.
 424 Use the `gnus-group-topics' to sort the groups.
 425 If PREDICATE is a function, list groups that the function returns non-nil;
 426 if it is t, list groups that have no unread articles.
 427 If LOWEST is non-nil, list all newsgroups of level LOWEST or higher."
 428   (set-buffer gnus-group-buffer)
 429   (let ((inhibit-read-only t)
 430         (lowest (or lowest 1))
 431         (not-in-list
 432          (and gnus-group-listed-groups
 433               (copy-sequence gnus-group-listed-groups))))
 434
 435     (gnus-update-format-specifications nil 'topic)
 436
 437     (when (or (not gnus-topic-alist)
 438               (not gnus-topology-checked-p))
 439       (gnus-topic-check-topology))
 440
 441     (unless list-topic
 442       (erase-buffer))
 443
 444     ;; List dead groups?
 445     (when (or gnus-group-listed-groups
 446               (and (>= level gnus-level-zombie)
 447                    (<= lowest gnus-level-zombie)))
 448       (gnus-group-prepare-flat-list-dead
 449        (setq gnus-zombie-list (sort gnus-zombie-list 'string<))
 450        gnus-level-zombie ?Z
 451        regexp))
 452
 453     (when (or gnus-group-listed-groups
 454                (and (>= level gnus-level-killed)
 455                     (<= lowest gnus-level-killed)))
 456       (gnus-group-prepare-flat-list-dead
 457        (setq gnus-killed-list (sort gnus-killed-list 'string<))
 458        gnus-level-killed ?K regexp)
 459       (when not-in-list
 460         (unless gnus-killed-hashtb
 461           (gnus-make-hashtable-from-killed))
 462         (gnus-group-prepare-flat-list-dead
 463          (seq-remove (lambda (group)
 464                            (or (gnus-group-entry group)
 465                                (gnus-gethash group gnus-killed-hashtb)))
 466                          not-in-list)
 467          gnus-level-killed ?K regexp)))
 468
 469     ;; Use topics.
 470     (prog1
 471         (when (or (< lowest gnus-level-zombie)
 472                   gnus-group-listed-groups)
 473           (if list-topic
 474               (let ((top (gnus-topic-find-topology list-topic)))
 475                 (gnus-topic-prepare-topic (cdr top) (car top)
 476                                           (or topic-level level) predicate
 477                                           nil lowest regexp))
 478             (gnus-topic-prepare-topic gnus-topic-topology 0
 479                                       (or topic-level level) predicate
 480                                       nil lowest regexp)))
 481       (gnus-group-set-mode-line)
 482       (setq gnus-group-list-mode (cons level predicate))
 483       (gnus-run-hooks 'gnus-group-prepare-hook))))
 484
 485 (defun gnus-topic-prepare-topic (topicl level &optional list-level
 486                                         predicate silent
 487                                         lowest regexp)
 488   "Insert TOPIC into the group buffer.
 489 If SILENT, don't insert anything.  Return the number of unread
 490 articles in the topic and its subtopics."
 491   (let* ((type (pop topicl))
 492          (entries (gnus-topic-find-groups
 493                    (car type)
 494                    (if gnus-group-listed-groups
 495                        gnus-level-killed
 496                      list-level)
 497                    (or predicate gnus-group-listed-groups
 498                        (cdr (assq 'visible
 499                                   (gnus-topic-hierarchical-parameters
 500                                    (car type)))))
 501                    (if gnus-group-listed-groups 0 lowest)))
 502          (visiblep (and (eq (nth 1 type) 'visible) (not silent)))
 503          (gnus-group-indentation
 504           (make-string (* gnus-topic-indent-level level) ? ))
 505          (beg (progn (beginning-of-line) (point)))
 506          (topicl (reverse topicl))
 507          (all-entries entries)
 508          (point-max (point-max))
 509          (unread 0)
 510          info entry end active tick)
 511     ;; Insert any sub-topics.
 512     (while topicl
 513       (incf unread
 514             (gnus-topic-prepare-topic
 515              (pop topicl) (1+ level) list-level predicate
 516              (not visiblep) lowest regexp)))
 517     (setq end (point))
 518     (goto-char beg)
 519     ;; Insert all the groups that belong in this topic.
 520     (while (setq entry (pop entries))
 521       (when (if (stringp entry)
 522                 (gnus-group-prepare-logic
 523                  entry
 524                  (and
 525                   (or (not gnus-group-listed-groups)
 526                       (if (< list-level gnus-level-zombie) nil
 527                         (let ((entry-level
 528                                (if (member entry gnus-zombie-list)
 529                                    gnus-level-zombie gnus-level-killed)))
 530                           (and (<= entry-level list-level)
 531                                (>= entry-level lowest)))))
 532                   (cond
 533                    ((stringp regexp)
 534                     (string-match regexp entry))
 535                    ((functionp regexp)
 536                     (funcall regexp entry))
 537                    ((null regexp) t)
 538                    (t nil))))
 539               (setq info (nth 2 entry))
 540               (gnus-group-prepare-logic
 541                (gnus-info-group info)
 542                (and (or (not gnus-group-listed-groups)
 543                         (let ((entry-level (gnus-info-level info)))
 544                           (and (<= entry-level list-level)
 545                                (>= entry-level lowest))))
 546                     (or (not (functionp predicate))
 547                         (funcall predicate info))
 548                     (or (not (stringp regexp))
 549                         (string-match regexp (gnus-info-group info))))))
 550         (when visiblep
 551           (if (stringp entry)
 552               ;; Dead groups.
 553               (gnus-group-insert-group-line
 554                entry (if (member entry gnus-zombie-list)
 555                          gnus-level-zombie gnus-level-killed)
 556                nil (- (1+ (cdr (setq active (gnus-active entry))))
 557                       (car active))
 558                nil)
 559             ;; Living groups.
 560             (when (setq info (nth 2 entry))
 561               (gnus-group-insert-group-line
 562                (gnus-info-group info)
 563                (gnus-info-level info) (gnus-info-marks info)
 564                (car entry) (gnus-info-method info)))))
 565         (when (and (listp entry)
 566                    (numberp (car entry)))
 567           (incf unread (car entry)))
 568         (when (listp entry)
 569           (setq tick t))))
 570     (goto-char beg)
 571     ;; Insert the topic line.
 572     (when (and (not silent)
 573                (or gnus-topic-display-empty-topics ;We want empty topics
 574                    (not (zerop unread)) ;Non-empty
 575                    tick                 ;Ticked articles
 576                    (/= point-max (point-max)))) ;Inactive groups
 577       (gnus-topic-insert-topic-line
 578        (car type) visiblep
 579        (not (eq (nth 2 type) 'hidden))
 580        level all-entries unread))
 581     (gnus-topic-update-unreads (car type) unread)
 582     (gnus-group--setup-tool-bar-update beg end)
 583     (goto-char end)
 584     unread))
 585
 586 (defun gnus-topic-remove-topic (&optional insert total-remove _hide in-level)
 587   "Remove the current topic."
 588   (let ((topic (gnus-group-topic-name))
 589         (level (gnus-group-topic-level))
 590         (beg (progn (beginning-of-line) (point)))
 591         buffer-read-only)
 592     (when topic
 593       (while (and (zerop (forward-line 1))
 594                   (> (or (gnus-group-topic-level) (1+ level)) level)))
 595       (delete-region beg (point))
 596       ;; Do the change in this rather odd manner because it has been
 597       ;; reported that some topics share parts of some lists, for some
 598       ;; reason.  I have been unable to determine why this is the
 599       ;; case, but this hack seems to take care of things.
 600       (let ((data (cadr (gnus-topic-find-topology topic))))
 601         (setcdr data
 602                 (list (if insert 'visible 'invisible)
 603                       (caddr data)
 604                       (cadddr data))))
 605       (if total-remove
 606           (setq gnus-topic-alist
 607                 (delq (assoc topic gnus-topic-alist) gnus-topic-alist))
 608         (gnus-topic-insert-topic topic in-level)))))
 609
 610 (defun gnus-topic-insert-topic (topic &optional level)
 611   "Insert TOPIC."
 612   (gnus-group-prepare-topics
 613    (car gnus-group-list-mode) (cdr gnus-group-list-mode)
 614    nil nil topic level))
 615
 616 (defun gnus-topic-fold (&optional insert topic)
 617   "Remove/insert the current topic."
 618   (let ((topic (or topic (gnus-group-topic-name))))
 619     (when topic
 620       (save-excursion
 621         (if (not (gnus-group-active-topic-p))
 622             (gnus-topic-remove-topic
 623              (or insert (not (gnus-topic-visible-p))))
 624           (let ((gnus-topic-topology gnus-topic-active-topology)
 625                 (gnus-topic-alist gnus-topic-active-alist)
 626                 (gnus-group-list-mode (cons 5 t)))
 627             (gnus-topic-remove-topic
 628              (or insert (not (gnus-topic-visible-p))) nil nil 9)
 629             (gnus-topic-enter-dribble)))))))
 630
 631 (defvar gnus-tmp-header)
 632
 633 (defun gnus-topic-insert-topic-line (name visiblep shownp level entries
 634                                           &optional unread)
 635   (let* ((visible (if visiblep "" "..."))
 636          (indentation (make-string (* gnus-topic-indent-level level) ? ))
 637          (total-number-of-articles unread)
 638          (number-of-groups (length entries))
 639          (active-topic (eq gnus-topic-alist gnus-topic-active-alist))
 640          gnus-tmp-header)
 641     (gnus-topic-update-unreads name unread)
 642     (beginning-of-line)
 643     ;; Insert the text.
 644     (if shownp
 645         (add-text-properties
 646          (point)
 647          (prog1 (1+ (point))
 648            (eval gnus-topic-line-format-spec))
 649          (list 'gnus-topic (intern name)
 650                'gnus-topic-level level
 651                'gnus-topic-unread unread
 652                'gnus-active active-topic
 653                'gnus-topic-visible visiblep)))))
 654
 655 (defun gnus-topic-update-unreads (topic unreads)
 656   (setq gnus-topic-unreads (delq (assoc topic gnus-topic-unreads)
 657                                  gnus-topic-unreads))
 658   (push (cons topic unreads) gnus-topic-unreads))
 659
 660 (defun gnus-topic-update-topics-containing-group (group)
 661   "Update all topics that have GROUP as a member."
 662   (when (and (eq major-mode 'gnus-group-mode)
 663              gnus-topic-mode)
 664     (save-excursion
 665       (let ((alist gnus-topic-alist))
 666         ;; This is probably not entirely correct.  If a topic
 667         ;; isn't shown, then it's not updated.  But the updating
 668         ;; should be performed in any case, since the topic's
 669         ;; parent should be updated.  Pfft.
 670         (while alist
 671           (when (and (member group (cdar alist))
 672                      (gnus-topic-goto-topic (caar alist)))
 673             (gnus-topic-update-topic-line (caar alist)))
 674           (pop alist))))))
 675
 676 (defun gnus-topic-update-topic ()
 677   "Update all parent topics to the current group."
 678   (when (and (eq major-mode 'gnus-group-mode)
 679              gnus-topic-mode)
 680     (let ((group (gnus-group-group-name))
 681           (m (point-marker))
 682           (inhibit-read-only t))
 683       (when (and group
 684                  (gnus-get-info group)
 685                  (gnus-topic-goto-topic (gnus-current-topic)))
 686         (gnus-topic-update-topic-line (gnus-group-topic-name))
 687         (goto-char m)
 688         (set-marker m nil)
 689         (gnus-group-position-point)))))
 690
 691 (defun gnus-topic-goto-missing-group (group)
 692   "Place point where GROUP is supposed to be inserted."
 693   (let* ((topic (gnus-group-topic group))
 694          (groups (cdr (assoc topic gnus-topic-alist)))
 695          (g (cdr (member group groups)))
 696          (unfound t))
 697     ;; Try to jump to a visible group.
 698     (while (and g
 699                 (not (gnus-group-goto-group (car g) t)))
 700       (pop g))
 701     ;; It wasn't visible, so we try to see where to insert it.
 702     (when (not g)
 703       (setq g (cdr (member group (reverse groups))))
 704       (while (and g unfound)
 705         (when (gnus-group-goto-group (pop g) t)
 706           (forward-line 1)
 707           (setq unfound nil)))
 708       (when (and unfound
 709                  topic
 710                  (not (gnus-topic-goto-missing-topic topic)))
 711         (gnus-topic-display-missing-topic topic)))))
 712
 713 (defun gnus-topic-display-missing-topic (topic)
 714   "Insert topic lines recursively for missing topics."
 715   (let ((parent (gnus-topic-find-topology
 716                  (gnus-topic-parent-topic topic))))
 717     (when (and parent
 718                (not (gnus-topic-goto-missing-topic (caadr parent))))
 719       (gnus-topic-display-missing-topic (caadr parent))))
 720   (gnus-topic-goto-missing-topic topic)
 721   ;; Skip past all groups in the topic we're in.
 722   (while (gnus-group-group-name)
 723     (forward-line 1))
 724   (let* ((top (gnus-topic-find-topology topic))
 725          (children (cddr top))
 726          (type (cadr top))
 727          (unread 0)
 728          (entries (gnus-topic-find-groups
 729                    (car type) (car gnus-group-list-mode)
 730                    (cdr gnus-group-list-mode)))
 731         entry)
 732     (while children
 733       (incf unread (gnus-topic-unread (caar (pop children)))))
 734     (while (setq entry (pop entries))
 735       (when (numberp (car entry))
 736         (incf unread (car entry))))
 737     (gnus-topic-insert-topic-line
 738      topic t t (car (gnus-topic-find-topology topic)) nil unread)))
 739
 740 (defun gnus-topic-goto-missing-topic (topic)
 741   (if (gnus-topic-goto-topic topic)
 742       (forward-line 1)
 743     ;; Topic not displayed.
 744     (let* ((top (gnus-topic-find-topology
 745                  (gnus-topic-parent-topic topic)))
 746            (tp (reverse (cddr top))))
 747       (if (not top)
 748           (gnus-topic-insert-topic-line
 749            topic t t (car (gnus-topic-find-topology topic)) nil 0)
 750         (while (not (equal (caaar tp) topic))
 751           (setq tp (cdr tp)))
 752         (pop tp)
 753         (while (and tp
 754                     (not (gnus-topic-goto-topic (caaar tp))))
 755           (pop tp))
 756         (if tp
 757             (gnus-topic-forward-topic 1)
 758           (gnus-topic-goto-missing-topic (caadr top)))))
 759     nil))
 760
 761 (defun gnus-topic-update-topic-line (topic-name &optional reads)
 762   (let* ((top (gnus-topic-find-topology topic-name))
 763          (type (cadr top))
 764          (children (cddr top))
 765          (entries (gnus-topic-find-groups
 766                    (car type) (car gnus-group-list-mode)
 767                    (cdr gnus-group-list-mode)))
 768          (parent (gnus-topic-parent-topic topic-name))
 769          (all-entries entries)
 770          (unread 0)
 771          old-unread entry new-unread)
 772     (when (gnus-topic-goto-topic (car type))
 773       ;; Tally all the groups that belong in this topic.
 774       (if reads
 775           (setq unread (- (gnus-group-topic-unread) reads))
 776         (while children
 777           (incf unread (gnus-topic-unread (caar (pop children)))))
 778         (while (setq entry (pop entries))
 779           (when (numberp (car entry))
 780             (incf unread (car entry)))))
 781       (setq old-unread (gnus-group-topic-unread))
 782       ;; Insert the topic line.
 783       (gnus-topic-insert-topic-line
 784        (car type) (gnus-topic-visible-p)
 785        (not (eq (nth 2 type) 'hidden))
 786        (gnus-group-topic-level) all-entries unread)
 787       (gnus-delete-line)
 788       (forward-line -1)
 789       (setq new-unread (gnus-group-topic-unread)))
 790     (when parent
 791       (forward-line -1)
 792       (gnus-topic-update-topic-line
 793        parent
 794        (- (or old-unread 0) (or new-unread 0))))
 795     unread))
 796
 797 (defun gnus-topic-group-indentation ()
 798   (make-string
 799    (* gnus-topic-indent-level
 800       (or (save-excursion
 801             (forward-line -1)
 802             (gnus-topic-goto-topic (gnus-current-topic))
 803             (gnus-group-topic-level))
 804           0))
 805    ? ))
 806
 807 ;;; Initialization
 808
 809 (gnus-add-shutdown 'gnus-topic-close 'gnus)
 810
 811 (defun gnus-topic-close ()
 812   (setq gnus-topic-active-topology nil
 813         gnus-topic-active-alist nil
 814         gnus-topic-killed-topics nil
 815         gnus-topology-checked-p nil))
 816
 817 (defun gnus-topic-check-topology ()
 818   ;; The first time we set the topology to whatever we have
 819   ;; gotten here, which can be rather random.
 820   (unless gnus-topic-alist
 821     (gnus-topic-init-alist))
 822
 823   (setq gnus-topology-checked-p t)
 824   ;; Go through the topic alist and make sure that all topics
 825   ;; are in the topic topology.
 826   (let ((topics (gnus-topic-list))
 827         (alist gnus-topic-alist)
 828         changed)
 829     (while alist
 830       (unless (member (caar alist) topics)
 831         (nconc gnus-topic-topology
 832                (list (list (list (caar alist) 'visible))))
 833         (setq changed t))
 834       (setq alist (cdr alist)))
 835     (when changed
 836       (gnus-topic-enter-dribble))
 837     ;; Conversely, go through the topology and make sure that all
 838     ;; topologies have alists.
 839     (while topics
 840       (unless (assoc (car topics) gnus-topic-alist)
 841         (push (list (car topics)) gnus-topic-alist))
 842       (pop topics)))
 843   ;; Go through all living groups and make sure that
 844   ;; they belong to some topic.
 845   (let* ((tgroups (apply 'append (mapcar 'cdr gnus-topic-alist)))
 846          (entry (last (assoc (caar gnus-topic-topology) gnus-topic-alist)))
 847          (newsrc (cdr gnus-newsrc-alist))
 848          group)
 849     (while newsrc
 850       (unless (member (setq group (gnus-info-group (pop newsrc))) tgroups)
 851         (setcdr entry (list group))
 852         (setq entry (cdr entry)))))
 853   ;; Go through all topics and make sure they contain only living groups.
 854   (let ((alist gnus-topic-alist)
 855         topic)
 856     (while (setq topic (pop alist))
 857       (while (cdr topic)
 858         (if (and (cadr topic)
 859                  (gnus-group-entry (cadr topic)))
 860             (setq topic (cdr topic))
 861           (setcdr topic (cddr topic)))))))
 862
 863 (defun gnus-topic-init-alist ()
 864   "Initialize the topic structures."
 865   (setq gnus-topic-topology
 866         (cons (list "Gnus" 'visible)
 867               (mapcar (lambda (topic)
 868                         (list (list (car topic) 'visible)))
 869                       '(("misc")))))
 870   (setq gnus-topic-alist
 871         (list (cons "misc"
 872                     (mapcar (lambda (info) (gnus-info-group info))
 873                             (cdr gnus-newsrc-alist)))
 874               (list "Gnus")))
 875   (gnus-topic-enter-dribble))
 876
 877 ;;; Maintenance
 878
 879 (defun gnus-topic-clean-alist ()
 880   "Remove bogus groups from the topic alist."
 881   (let ((topic-alist gnus-topic-alist)
 882         result topic)
 883     (unless gnus-killed-hashtb
 884       (gnus-make-hashtable-from-killed))
 885     (while (setq topic (pop topic-alist))
 886       (let ((topic-name (pop topic))
 887             group filtered-topic)
 888         (while (setq group (pop topic))
 889           (when (and (or (gnus-active group)
 890                          (gnus-info-method (gnus-get-info group)))
 891                      (not (gnus-gethash group gnus-killed-hashtb)))
 892             (push group filtered-topic)))
 893         (push (cons topic-name (nreverse filtered-topic)) result)))
 894     (setq gnus-topic-alist (nreverse result))))
 895
 896 (defun gnus-topic-change-level (group level oldlevel &optional previous)
 897   "Run when changing levels to enter/remove groups from topics."
 898   (with-current-buffer gnus-group-buffer
 899     (let ((inhibit-read-only t))
 900       (unless gnus-topic-inhibit-change-level
 901         (gnus-group-goto-group (or (car (nth 2 previous)) group))
 902         (when (and gnus-topic-mode
 903                    gnus-topic-alist
 904                    (not gnus-topic-inhibit-change-level))
 905           ;; Remove the group from the topics.
 906           (if (and (< oldlevel gnus-level-zombie)
 907                    (>= level gnus-level-zombie))
 908               (let ((alist gnus-topic-alist))
 909                 (while (gnus-group-goto-group group)
 910                   (gnus-delete-line))
 911                 (while alist
 912                   (when (member group (car alist))
 913                     (setcdr (car alist) (delete group (cdar alist))))
 914                   (pop alist)))
 915             ;; If the group is subscribed we enter it into the topics.
 916             (when (and (< level gnus-level-zombie)
 917                        (>= oldlevel gnus-level-zombie))
 918               (let* ((prev (gnus-group-group-name))
 919                      (gnus-topic-inhibit-change-level t)
 920                      (gnus-group-indentation
 921                       (make-string
 922                        (* gnus-topic-indent-level
 923                           (or (save-excursion
 924                                 (gnus-topic-goto-topic (gnus-current-topic))
 925                                 (gnus-group-topic-level))
 926                               0))
 927                        ? ))
 928                      (yanked (list group))
 929                      alist talist end)
 930                 ;; Then we enter the yanked groups into the topics
 931                 ;; they belong to.
 932                 (when (setq alist (assoc (save-excursion
 933                                            (forward-line -1)
 934                                            (or
 935                                             (gnus-current-topic)
 936                                             (caar gnus-topic-topology)))
 937                                          gnus-topic-alist))
 938                   (setq talist alist)
 939                   (when (stringp yanked)
 940                     (setq yanked (list yanked)))
 941                   (if (not prev)
 942                       (nconc alist yanked)
 943                     (if (not (cdr alist))
 944                         (setcdr alist (nconc yanked (cdr alist)))
 945                       (while (and (not end) (cdr alist))
 946                         (when (equal (cadr alist) prev)
 947                           (setcdr alist (nconc yanked (cdr alist)))
 948                           (setq end t))
 949                         (setq alist (cdr alist)))
 950                       (unless end
 951                         (nconc talist yanked))))))
 952               (gnus-topic-update-topic))))))))
 953
 954 (defun gnus-topic-goto-next-group (group props)
 955   "Go to group or the next group after group."
 956   (if (not group)
 957       (if (not (memq 'gnus-topic props))
 958           (goto-char (point-max))
 959         (let ((topic (symbol-name (cadr (memq 'gnus-topic props)))))
 960           (or (gnus-topic-goto-topic topic)
 961               (gnus-topic-goto-topic (gnus-topic-next-topic topic)))))
 962     (if (gnus-group-goto-group group)
 963         t
 964       ;; The group is no longer visible.
 965       (let* ((list (assoc (gnus-group-topic group) gnus-topic-alist))
 966              (topic-visible (save-excursion (gnus-topic-goto-topic (car list))))
 967              (after (and topic-visible (cdr (member group (cdr list))))))
 968         ;; First try to put point on a group after the current one.
 969         (while (and after
 970                     (not (gnus-group-goto-group (car after))))
 971           (setq after (cdr after)))
 972         ;; Then try to put point on a group before point.
 973         (unless after
 974           (setq after (cdr (member group (reverse (cdr list)))))
 975           (while (and after
 976                       (not (gnus-group-goto-group (car after))))
 977             (setq after (cdr after))))
 978         ;; Finally, just put point on the topic.
 979         (if (not (car list))
 980             (goto-char (point-min))
 981           (unless after
 982             (if topic-visible
 983                 (gnus-goto-char topic-visible)
 984               (gnus-topic-goto-topic (gnus-topic-next-topic (car list))))
 985             (setq after nil)))
 986         t))))
 987
 988 ;;; Topic-active functions
 989
 990 (defun gnus-topic-grok-active (&optional force)
 991   "Parse all active groups and create topic structures for them."
 992   ;; First we make sure that we have really read the active file.
 993   (when (or force
 994             (not gnus-topic-active-alist))
 995     (let (groups)
 996       ;; Get a list of all groups available.
 997       (mapatoms (lambda (g) (when (symbol-value g)
 998                               (push (symbol-name g) groups)))
 999                 gnus-active-hashtb)
1000       (setq groups (sort groups 'string<))
1001       ;; Init the variables.
1002       (setq gnus-topic-active-topology (list (list "" 'visible)))
1003       (setq gnus-topic-active-alist nil)
1004       ;; Descend the top-level hierarchy.
1005       (gnus-topic-grok-active-1 gnus-topic-active-topology groups)
1006       ;; Set the top-level topic names to something nice.
1007       (setcar (car gnus-topic-active-topology) "Gnus active")
1008       (setcar (car gnus-topic-active-alist) "Gnus active"))))
1009
1010 (defun gnus-topic-grok-active-1 (topology groups)
1011   (let* ((name (caar topology))
1012          (prefix (concat "^" (regexp-quote name)))
1013          tgroups ntopology group)
1014     (while (and groups
1015                 (string-match prefix (setq group (car groups))))
1016       (if (not (string-match "\\." group (match-end 0)))
1017           ;; There are no further hierarchies here, so we just
1018           ;; enter this group into the list belonging to this
1019           ;; topic.
1020           (push (pop groups) tgroups)
1021         ;; New sub-hierarchy, so we add it to the topology.
1022         (nconc topology (list (setq ntopology
1023                                     (list (list (substring
1024                                                  group 0 (match-end 0))
1025                                                 'invisible)))))
1026         ;; Descend the hierarchy.
1027         (setq groups (gnus-topic-grok-active-1 ntopology groups))))
1028     ;; We remove the trailing "." from the topic name.
1029     (setq name
1030           (if (string-match "\\.$" name)
1031               (substring name 0 (match-beginning 0))
1032             name))
1033     ;; Add this topic and its groups to the topic alist.
1034     (push (cons name (nreverse tgroups)) gnus-topic-active-alist)
1035     (setcar (car topology) name)
1036     ;; We return the rest of the groups that didn't belong
1037     ;; to this topic.
1038     groups))
1039
1040 ;;; Topic mode, commands and keymap.
1041
1042 (defvar gnus-topic-mode-map nil)
1043 (defvar gnus-group-topic-map nil)
1044
1045 (unless gnus-topic-mode-map
1046   (setq gnus-topic-mode-map (make-sparse-keymap))
1047
1048   ;; Override certain group mode keys.
1049   (gnus-define-keys gnus-topic-mode-map
1050     "=" gnus-topic-select-group
1051     "\r" gnus-topic-select-group
1052     " " gnus-topic-read-group
1053     "\C-c\C-x" gnus-topic-expire-articles
1054     "c" gnus-topic-catchup-articles
1055     "\C-k" gnus-topic-kill-group
1056     "\C-y" gnus-topic-yank-group
1057     "\M-g" gnus-topic-get-new-news-this-topic
1058     "AT" gnus-topic-list-active
1059     "Gp" gnus-topic-edit-parameters
1060     "#" gnus-topic-mark-topic
1061     "\M-#" gnus-topic-unmark-topic
1062     [tab] gnus-topic-indent
1063     [(meta tab)] gnus-topic-unindent
1064     "\C-i" gnus-topic-indent
1065     "\M-\C-i" gnus-topic-unindent
1066     [mouse-2] gnus-mouse-pick-topic)
1067
1068   ;; Define a new submap.
1069   (gnus-define-keys (gnus-group-topic-map "T" gnus-group-mode-map)
1070     "#" gnus-topic-mark-topic
1071     "\M-#" gnus-topic-unmark-topic
1072     "n" gnus-topic-create-topic
1073     "m" gnus-topic-move-group
1074     "D" gnus-topic-remove-group
1075     "c" gnus-topic-copy-group
1076     "h" gnus-topic-hide-topic
1077     "s" gnus-topic-show-topic
1078     "j" gnus-topic-jump-to-topic
1079     "M" gnus-topic-move-matching
1080     "C" gnus-topic-copy-matching
1081     "\M-p" gnus-topic-goto-previous-topic
1082     "\M-n" gnus-topic-goto-next-topic
1083     "\C-i" gnus-topic-indent
1084     [tab] gnus-topic-indent
1085     "r" gnus-topic-rename
1086     "\177" gnus-topic-delete
1087     [delete] gnus-topic-delete
1088     "H" gnus-topic-toggle-display-empty-topics)
1089
1090   (gnus-define-keys (gnus-topic-sort-map "S" gnus-group-topic-map)
1091     "s" gnus-topic-sort-groups
1092     "a" gnus-topic-sort-groups-by-alphabet
1093     "u" gnus-topic-sort-groups-by-unread
1094     "l" gnus-topic-sort-groups-by-level
1095     "e" gnus-topic-sort-groups-by-server
1096     "v" gnus-topic-sort-groups-by-score
1097     "r" gnus-topic-sort-groups-by-rank
1098     "m" gnus-topic-sort-groups-by-method))
1099
1100 (defun gnus-topic-make-menu-bar ()
1101   (unless (boundp 'gnus-topic-menu)
1102     (easy-menu-define
1103      gnus-topic-menu gnus-topic-mode-map ""
1104      '("Topics"
1105        ["Toggle topics" gnus-topic-mode t]
1106        ("Groups"
1107         ["Copy..." gnus-topic-copy-group t]
1108         ["Move..." gnus-topic-move-group t]
1109         ["Remove" gnus-topic-remove-group t]
1110         ["Copy matching..." gnus-topic-copy-matching t]
1111         ["Move matching..." gnus-topic-move-matching t])
1112        ("Topics"
1113         ["Goto..." gnus-topic-jump-to-topic t]
1114         ["Show" gnus-topic-show-topic t]
1115         ["Hide" gnus-topic-hide-topic t]
1116         ["Delete" gnus-topic-delete t]
1117         ["Rename..." gnus-topic-rename t]
1118         ["Create..." gnus-topic-create-topic t]
1119         ["Mark" gnus-topic-mark-topic t]
1120         ["Indent" gnus-topic-indent t]
1121         ["Sort" gnus-topic-sort-topics t]
1122         ["Previous topic" gnus-topic-goto-previous-topic t]
1123         ["Next topic" gnus-topic-goto-next-topic t]
1124         ["Toggle hide empty" gnus-topic-toggle-display-empty-topics t]
1125         ["Edit parameters" gnus-topic-edit-parameters t])
1126        ["List active" gnus-topic-list-active t]))))
1127
1128 (define-minor-mode gnus-topic-mode
1129   "Minor mode for topicsifying Gnus group buffers."
1130   :lighter " Topic" :keymap gnus-topic-mode-map
1131   (if (not (derived-mode-p 'gnus-group-mode))
1132       (setq gnus-topic-mode nil)
1133     ;; Infest Gnus with topics.
1134     (if (not gnus-topic-mode)
1135         (setq gnus-goto-missing-group-function nil)
1136       (when (gnus-visual-p 'topic-menu 'menu)
1137         (gnus-topic-make-menu-bar))
1138       (gnus-set-format 'topic t)
1139       (add-hook 'gnus-group-catchup-group-hook 'gnus-topic-update-topic)
1140       (set (make-local-variable 'gnus-group-prepare-function)
1141            'gnus-group-prepare-topics)
1142       (set (make-local-variable 'gnus-group-get-parameter-function)
1143            'gnus-group-topic-parameters)
1144       (set (make-local-variable 'gnus-group-goto-next-group-function)
1145            'gnus-topic-goto-next-group)
1146       (set (make-local-variable 'gnus-group-indentation-function)
1147            'gnus-topic-group-indentation)
1148       (set (make-local-variable 'gnus-group-update-group-function)
1149            'gnus-topic-update-topics-containing-group)
1150       (set (make-local-variable 'gnus-group-sort-alist-function)
1151            'gnus-group-sort-topic)
1152       (setq gnus-group-change-level-function 'gnus-topic-change-level)
1153       (setq gnus-goto-missing-group-function 'gnus-topic-goto-missing-group)
1154       (add-hook 'gnus-check-bogus-groups-hook 'gnus-topic-clean-alist
1155                 nil 'local)
1156       (setq gnus-topology-checked-p nil)
1157       ;; We check the topology.
1158       (when gnus-newsrc-alist
1159         (gnus-topic-check-topology)))
1160     ;; Remove topic infestation.
1161     (unless gnus-topic-mode
1162       (remove-hook 'gnus-summary-exit-hook 'gnus-topic-update-topic)
1163       (setq gnus-group-change-level-function nil)
1164       (remove-hook 'gnus-check-bogus-groups-hook 'gnus-topic-clean-alist)
1165       (setq gnus-group-prepare-function 'gnus-group-prepare-flat)
1166       (setq gnus-group-sort-alist-function 'gnus-group-sort-flat))
1167     (when (called-interactively-p 'any)
1168       (gnus-group-list-groups))))
1169
1170 (defun gnus-topic-select-group (&optional all)
1171   "Select this newsgroup.
1172 No article is selected automatically.
1173 If the group is opened, just switch the summary buffer.
1174 If ALL is non-nil, already read articles become readable.
1175
1176 If ALL is a positive number, fetch this number of the latest
1177 articles in the group.  If ALL is a negative number, fetch this
1178 number of the earliest articles in the group.
1179
1180 If performed over a topic line, toggle folding the topic."
1181   (interactive "P")
1182   (when (and (eobp) (not (gnus-group-group-name)))
1183     (forward-line -1))
1184   (if (gnus-group-topic-p)
1185       (let ((gnus-group-list-mode
1186              (if all (cons (if (numberp all) all 7) t) gnus-group-list-mode)))
1187         (gnus-topic-fold all)
1188         (gnus-dribble-touch))
1189     (gnus-group-select-group all)))
1190
1191 (defun gnus-mouse-pick-topic (e)
1192   "Select the group or topic under the mouse pointer."
1193   (interactive "e")
1194   (mouse-set-point e)
1195   (gnus-topic-read-group nil))
1196
1197 (defun gnus-topic-expire-articles (topic)
1198   "Expire articles in this topic or group."
1199   (interactive (list (gnus-group-topic-name)))
1200   (if (not topic)
1201       (call-interactively 'gnus-group-expire-articles)
1202     (save-excursion
1203       (gnus-message 5 "Expiring groups in %s..." topic)
1204       (let ((gnus-group-marked
1205              (mapcar (lambda (entry) (car (nth 2 entry)))
1206                      (gnus-topic-find-groups topic gnus-level-killed t
1207                                              nil t))))
1208         (gnus-group-expire-articles nil))
1209       (gnus-message 5 "Expiring groups in %s...done" topic))))
1210
1211 (defun gnus-topic-catchup-articles (topic)
1212   "Catchup this topic or group.
1213 Also see `gnus-group-catchup'."
1214   (interactive (list (gnus-group-topic-name)))
1215   (if (not topic)
1216       (call-interactively 'gnus-group-catchup-current)
1217     (save-excursion
1218       (let* ((groups
1219               (mapcar (lambda (entry) (car (nth 2 entry)))
1220                       (gnus-topic-find-groups topic gnus-level-killed t
1221                                               nil t)))
1222              (inhibit-read-only t)
1223              (gnus-group-marked groups))
1224         (gnus-group-catchup-current)
1225         (mapcar 'gnus-topic-update-topics-containing-group groups)))))
1226
1227 (defun gnus-topic-read-group (&optional all no-article group)
1228   "Read news in this newsgroup.
1229 If the prefix argument ALL is non-nil, already read articles become
1230 readable.
1231
1232 If ALL is a positive number, fetch this number of the latest
1233 articles in the group.  If ALL is a negative number, fetch this
1234 number of the earliest articles in the group.
1235
1236 If the optional argument NO-ARTICLE is non-nil, no article will
1237 be auto-selected upon group entry.  If GROUP is non-nil, fetch
1238 that group.
1239
1240 If performed over a topic line, toggle folding the topic."
1241   (interactive "P")
1242   (when (and (eobp) (not (gnus-group-group-name)))
1243     (forward-line -1))
1244   (if (gnus-group-topic-p)
1245       (let ((gnus-group-list-mode
1246              (if all (cons (if (numberp all) all 7) t) gnus-group-list-mode)))
1247         (gnus-topic-fold all))
1248     (gnus-group-read-group all no-article group)))
1249
1250 (defun gnus-topic-create-topic (topic parent &optional previous full-topic)
1251   "Create a new TOPIC under PARENT.
1252 When used interactively, PARENT will be the topic under point."
1253   (interactive
1254    (list
1255     (read-string "New topic: ")
1256     (gnus-current-topic)))
1257   ;; Check whether this topic already exists.
1258   (when (gnus-topic-find-topology topic)
1259     (error "Topic already exists"))
1260   (unless parent
1261     (setq parent (caar gnus-topic-topology)))
1262   (let ((top (cdr (gnus-topic-find-topology parent)))
1263         (full-topic (or full-topic (list (list topic 'visible nil nil)))))
1264     (unless top
1265       (error "No such parent topic: %s" parent))
1266     (if previous
1267         (progn
1268           (while (and (cdr top)
1269                       (not (equal (caaadr top) previous)))
1270             (setq top (cdr top)))
1271           (setcdr top (cons full-topic (cdr top))))
1272       (nconc top (list full-topic)))
1273     (unless (assoc topic gnus-topic-alist)
1274       (push (list topic) gnus-topic-alist)))
1275   (gnus-topic-enter-dribble)
1276   (gnus-group-list-groups)
1277   (gnus-topic-goto-topic topic))
1278
1279 ;; FIXME:
1280 ;;  1. When the marked groups are overlapped with the process
1281 ;;     region, the behavior of move or remove is not right.
1282 ;;  2. Can't process on several marked groups with a same name,
1283 ;;     because gnus-group-marked only keeps one copy.
1284
1285 (defvar gnus-topic-history nil)
1286
1287 (defun gnus-topic-move-group (n topic &optional copyp)
1288   "Move the next N groups to TOPIC.
1289 If COPYP, copy the groups instead."
1290   (interactive
1291    (list current-prefix-arg
1292          (gnus-completing-read "Move to topic" (mapcar 'car gnus-topic-alist) t
1293                                nil 'gnus-topic-history)))
1294   (let ((use-marked (and (not n) (not (and transient-mark-mode mark-active))
1295                          gnus-group-marked t))
1296         (groups (gnus-group-process-prefix n))
1297         (topicl (assoc topic gnus-topic-alist))
1298         (start-topic (gnus-group-topic-name))
1299         (start-group (progn (forward-line 1) (gnus-group-group-name)))
1300         entry)
1301     (if (and (not groups) (not copyp) start-topic)
1302         (gnus-topic-move start-topic topic)
1303       (dolist (g groups)
1304         (gnus-group-remove-mark g use-marked)
1305         (when (and
1306                (setq entry (assoc (gnus-current-topic) gnus-topic-alist))
1307                (not copyp))
1308           (setcdr entry (gnus-delete-first g (cdr entry))))
1309         (nconc topicl (list g)))
1310       (gnus-topic-enter-dribble)
1311       (if start-group
1312           (gnus-group-goto-group start-group)
1313         (gnus-topic-goto-topic start-topic))
1314       (gnus-group-list-groups))))
1315
1316 (defun gnus-topic-remove-group (&optional n)
1317   "Remove the current group from the topic."
1318   (interactive "P")
1319   (let ((use-marked (and (not n) (not (and transient-mark-mode mark-active))
1320                          gnus-group-marked t))
1321         (groups (gnus-group-process-prefix n)))
1322     (mapc
1323      (lambda (group)
1324        (gnus-group-remove-mark group use-marked)
1325        (let ((topicl (assoc (gnus-current-topic) gnus-topic-alist))
1326              (inhibit-read-only t))
1327          (when (and topicl group)
1328            (gnus-delete-line)
1329            (gnus-delete-first group topicl))
1330          (gnus-topic-update-topic)))
1331      groups)
1332     (gnus-topic-enter-dribble)
1333     (gnus-group-position-point)))
1334
1335 (defun gnus-topic-copy-group (n topic)
1336   "Copy the current group to a topic."
1337   (interactive
1338    (list current-prefix-arg
1339          (gnus-completing-read
1340           "Copy to topic" (mapcar 'car gnus-topic-alist) t)))
1341   (gnus-topic-move-group n topic t))
1342
1343 (defun gnus-topic-kill-group (&optional n discard)
1344   "Kill the next N groups."
1345   (interactive "P")
1346   (if (gnus-group-topic-p)
1347       (let ((topic (gnus-group-topic-name)))
1348         (push (cons
1349                (gnus-topic-find-topology topic)
1350                (assoc topic gnus-topic-alist))
1351               gnus-topic-killed-topics)
1352         (gnus-topic-remove-topic nil t)
1353         (gnus-topic-find-topology topic nil nil gnus-topic-topology)
1354         (gnus-topic-enter-dribble))
1355     (gnus-group-kill-group n discard)
1356     (if (not (gnus-group-topic-p))
1357         (gnus-topic-update-topic)
1358       ;; Move up one line so that we update the right topic.
1359       (forward-line -1)
1360       (gnus-topic-update-topic)
1361       (forward-line 1))))
1362
1363 (defun gnus-topic-yank-group (&optional arg)
1364   "Yank the last topic."
1365   (interactive "p")
1366   (if gnus-topic-killed-topics
1367       (let* ((previous
1368               (or (gnus-group-topic-name)
1369                   (gnus-topic-next-topic (gnus-current-topic))))
1370              (data (pop gnus-topic-killed-topics))
1371              (alist (cdr data))
1372              (item (cdar data)))
1373         (push alist gnus-topic-alist)
1374         (gnus-topic-create-topic
1375          (caar item) (gnus-topic-parent-topic previous) previous
1376          item)
1377         (gnus-topic-enter-dribble)
1378         (gnus-topic-goto-topic (caar item)))
1379     (let* ((prev (gnus-group-group-name))
1380            (gnus-topic-inhibit-change-level t)
1381            (gnus-group-indentation
1382             (make-string
1383              (* gnus-topic-indent-level
1384                 (or (save-excursion
1385                       (gnus-topic-goto-topic (gnus-current-topic))
1386                       (gnus-group-topic-level))
1387                     0))
1388              ? ))
1389            yanked alist)
1390       ;; We first yank the groups the normal way...
1391       (setq yanked (gnus-group-yank-group arg))
1392       ;; Then we enter the yanked groups into the topics they belong
1393       ;; to.
1394       (setq alist (assoc (save-excursion
1395                            (forward-line -1)
1396                            (gnus-current-topic))
1397                          gnus-topic-alist))
1398       (when (stringp yanked)
1399         (setq yanked (list yanked)))
1400       (if (not prev)
1401           (nconc alist yanked)
1402         (if (not (cdr alist))
1403             (setcdr alist (nconc yanked (cdr alist)))
1404           (while (cdr alist)
1405             (when (equal (cadr alist) prev)
1406               (setcdr alist (nconc yanked (cdr alist)))
1407               (setq alist nil))
1408             (setq alist (cdr alist))))))
1409     (gnus-topic-update-topic)))
1410
1411 (defun gnus-topic-hide-topic (&optional permanent)
1412   "Hide the current topic.
1413 If PERMANENT, make it stay hidden in subsequent sessions as well."
1414   (interactive "P")
1415   (when (gnus-current-topic)
1416     (gnus-topic-goto-topic (gnus-current-topic))
1417     (if permanent
1418         (setcar (cddr
1419                  (cadr
1420                   (gnus-topic-find-topology (gnus-current-topic))))
1421                 'hidden))
1422     (gnus-topic-remove-topic nil nil)))
1423
1424 (defun gnus-topic-show-topic (&optional permanent)
1425   "Show the hidden topic.
1426 If PERMANENT, make it stay shown in subsequent sessions as well."
1427   (interactive "P")
1428   (when (gnus-group-topic-p)
1429     (if (not permanent)
1430         (gnus-topic-remove-topic t nil)
1431       (let ((topic
1432              (gnus-topic-find-topology
1433               (gnus-completing-read "Show topic"
1434                                     (mapcar 'car gnus-topic-alist) t))))
1435         (setcar (cddr (cadr topic)) nil)
1436         (setcar (cdr (cadr topic)) 'visible)
1437         (gnus-group-list-groups)))))
1438
1439 (defun gnus-topic-mark-topic (topic &optional unmark non-recursive)
1440   "Mark all groups in the TOPIC with the process mark.
1441 If NON-RECURSIVE (which is the prefix) is t, don't mark its subtopics."
1442   (interactive (list (gnus-group-topic-name)
1443                      nil
1444                      (and current-prefix-arg t)))
1445   (if (not topic)
1446       (call-interactively 'gnus-group-mark-group)
1447     (save-excursion
1448       (let ((groups (gnus-topic-find-groups topic gnus-level-killed t nil
1449                                             (not non-recursive))))
1450         (while groups
1451           (funcall (if unmark 'gnus-group-remove-mark 'gnus-group-set-mark)
1452                    (gnus-info-group (nth 2 (pop groups)))))))))
1453
1454 (defun gnus-topic-unmark-topic (topic &optional _dummy non-recursive)
1455   "Remove the process mark from all groups in the TOPIC.
1456 If NON-RECURSIVE (which is the prefix) is t, don't unmark its subtopics."
1457   (interactive (list (gnus-group-topic-name)
1458                      nil
1459                      (and current-prefix-arg t)))
1460   (if (not topic)
1461       (call-interactively 'gnus-group-unmark-group)
1462     (gnus-topic-mark-topic topic t non-recursive)))
1463
1464 (defun gnus-topic-get-new-news-this-topic (&optional n)
1465   "Check for new news in the current topic."
1466   (interactive "P")
1467   (if (not (gnus-group-topic-p))
1468       (gnus-group-get-new-news-this-group n)
1469     (let* ((topic (gnus-group-topic-name))
1470            (data (cadr (gnus-topic-find-topology topic))))
1471       (save-excursion
1472         (gnus-topic-mark-topic topic nil (and n t))
1473         (gnus-group-get-new-news-this-group))
1474       (gnus-topic-remove-topic (eq 'visible (cadr data))))))
1475
1476 (defun gnus-topic-move-matching (regexp topic &optional copyp)
1477   "Move all groups that match REGEXP to some topic."
1478   (interactive
1479    (let (topic)
1480      (nreverse
1481       (list
1482        (setq topic (gnus-completing-read "Move to topic"
1483                                          (mapcar 'car gnus-topic-alist) t))
1484        (read-string (format "Move to %s (regexp): " topic))))))
1485   (gnus-group-mark-regexp regexp)
1486   (gnus-topic-move-group nil topic copyp))
1487
1488 (defun gnus-topic-copy-matching (regexp topic &optional _copyp)
1489   "Copy all groups that match REGEXP to some topic."
1490   (interactive
1491    (let ((topic (gnus-completing-read "Copy to topic"
1492                                       (mapcar #'car gnus-topic-alist) t)))
1493      (nreverse
1494       (list topic
1495             (read-string (format "Copy to %s (regexp): " topic))))))
1496   (gnus-topic-move-matching regexp topic t))
1497
1498 (defun gnus-topic-delete (topic)
1499   "Delete a topic."
1500   (interactive (list (gnus-group-topic-name)))
1501   (unless topic
1502     (error "No topic to be deleted"))
1503   (let ((entry (assoc topic gnus-topic-alist))
1504         (inhibit-read-only t))
1505     (when (cdr entry)
1506       (error "Topic not empty"))
1507     ;; Delete if visible.
1508     (when (gnus-topic-goto-topic topic)
1509       (gnus-delete-line))
1510     ;; Remove from alist.
1511     (setq gnus-topic-alist (delq entry gnus-topic-alist))
1512     ;; Remove from topology.
1513     (gnus-topic-find-topology topic nil nil 'delete)
1514     (gnus-dribble-touch)))
1515
1516 (defun gnus-topic-rename (old-name new-name)
1517   "Rename a topic."
1518   (interactive
1519    (let ((topic (gnus-current-topic)))
1520      (list topic
1521            (read-string (format "Rename %s to: " topic) topic))))
1522   ;; Check whether the new name exists.
1523   (when (gnus-topic-find-topology new-name)
1524     (error "Topic `%s' already exists" new-name))
1525   ;; "nil" is an invalid name, for reasons I'd rather not go
1526   ;; into here.  Trust me.
1527   (when (equal new-name "nil")
1528     (error "Invalid name: %s" nil))
1529   ;; Do the renaming.
1530   (let ((top (gnus-topic-find-topology old-name))
1531         (entry (assoc old-name gnus-topic-alist)))
1532     (when top
1533       (setcar (cadr top) new-name))
1534     (when entry
1535       (setcar entry new-name))
1536     (forward-line -1)
1537     (gnus-dribble-touch)
1538     (gnus-group-list-groups)
1539     (forward-line 1)))
1540
1541 (defun gnus-topic-indent (&optional unindent)
1542   "Indent a topic -- make it a sub-topic of the previous topic.
1543 If UNINDENT, remove an indentation."
1544   (interactive "P")
1545   (if unindent
1546       (gnus-topic-unindent)
1547     (let* ((topic (gnus-current-topic))
1548            (parent (gnus-topic-previous-topic topic))
1549            (inhibit-read-only t))
1550       (unless parent
1551         (error "Nothing to indent %s into" topic))
1552       (when topic
1553         (gnus-topic-goto-topic topic)
1554         (gnus-topic-kill-group)
1555         (push (cdar gnus-topic-killed-topics) gnus-topic-alist)
1556         (gnus-topic-create-topic
1557          topic parent nil (cdar (car gnus-topic-killed-topics)))
1558         (pop gnus-topic-killed-topics)
1559         (or (gnus-topic-goto-topic topic)
1560             (gnus-topic-goto-topic parent))))))
1561
1562 (defun gnus-topic-unindent ()
1563   "Unindent a topic."
1564   (interactive)
1565   (let* ((topic (gnus-current-topic))
1566          (parent (gnus-topic-parent-topic topic))
1567          (grandparent (gnus-topic-parent-topic parent)))
1568     (unless grandparent
1569       (error "Can't unindent %s further" topic))
1570     (when topic
1571       (gnus-topic-goto-topic topic)
1572       (gnus-topic-kill-group)
1573       (push (cdar gnus-topic-killed-topics) gnus-topic-alist)
1574       (gnus-topic-create-topic
1575        topic grandparent (gnus-topic-next-topic parent)
1576        (cdar (car gnus-topic-killed-topics)))
1577       (pop gnus-topic-killed-topics)
1578       (gnus-topic-goto-topic topic))))
1579
1580 (defun gnus-topic-list-active (&optional force)
1581   "List all groups that Gnus knows about in a topicsified fashion.
1582 If FORCE, always re-read the active file."
1583   (interactive "P")
1584   (when force
1585     (gnus-get-killed-groups))
1586   (gnus-topic-grok-active force)
1587   (let ((gnus-topic-topology gnus-topic-active-topology)
1588         (gnus-topic-alist gnus-topic-active-alist)
1589         gnus-killed-list gnus-zombie-list)
1590     (gnus-group-list-groups gnus-level-killed nil 1)))
1591
1592 (defun gnus-topic-toggle-display-empty-topics ()
1593   "Show/hide topics that have no unread articles."
1594   (interactive)
1595   (setq gnus-topic-display-empty-topics
1596         (not gnus-topic-display-empty-topics))
1597   (gnus-group-list-groups)
1598   (message "%s empty topics"
1599            (if gnus-topic-display-empty-topics
1600                "Showing" "Hiding")))
1601
1602 ;;; Topic sorting functions
1603
1604 (defun gnus-topic-edit-parameters (group)
1605   "Edit the group parameters of GROUP.
1606 If performed on a topic, edit the topic parameters instead."
1607   (interactive (list (gnus-group-group-name)))
1608   (if group
1609       (gnus-group-edit-group-parameters group)
1610     (if (not (gnus-group-topic-p))
1611         (error "Nothing to edit on the current line")
1612       (let ((topic (gnus-group-topic-name)))
1613         (gnus-edit-form
1614          (gnus-topic-parameters topic)
1615          (format-message "Editing the topic parameters for `%s'."
1616                          (or group topic))
1617          `(lambda (form)
1618             (gnus-topic-set-parameters ,topic form)))))))
1619
1620 (defun gnus-group-sort-topic (func reverse)
1621   "Sort groups in the topics according to FUNC and REVERSE."
1622   (let ((alist gnus-topic-alist))
1623     (while alist
1624       ;; !!!Sometimes nil elements sneak into the alist,
1625       ;; for some reason or other.
1626       (setcar alist (delq nil (car alist)))
1627       (setcar alist (delete "dummy.group" (car alist)))
1628       (gnus-topic-sort-topic (pop alist) func reverse))))
1629
1630 (defun gnus-topic-sort-topic (topic func reverse)
1631   ;; Each topic only lists the name of the group, while
1632   ;; the sort predicates expect group infos as inputs.
1633   ;; So we first transform the group names into infos,
1634   ;; then sort, and then transform back into group names.
1635   (setcdr
1636    topic
1637    (mapcar
1638     (lambda (info) (gnus-info-group info))
1639     (sort
1640      (mapcar
1641       (lambda (group) (gnus-get-info group))
1642       (cdr topic))
1643      func)))
1644   ;; Do the reversal, if necessary.
1645   (when reverse
1646     (setcdr topic (nreverse (cdr topic)))))
1647
1648 (defun gnus-topic-sort-groups (func &optional reverse)
1649   "Sort the current topic according to FUNC.
1650 If REVERSE, reverse the sorting order."
1651   (interactive (list gnus-group-sort-function current-prefix-arg))
1652   (let ((topic (assoc (gnus-current-topic) gnus-topic-alist)))
1653     (gnus-topic-sort-topic
1654      topic (gnus-make-sort-function func) reverse)
1655     (gnus-group-list-groups)))
1656
1657 (defun gnus-topic-sort-groups-by-alphabet (&optional reverse)
1658   "Sort the current topic alphabetically by group name.
1659 If REVERSE, sort in reverse order."
1660   (interactive "P")
1661   (gnus-topic-sort-groups 'gnus-group-sort-by-alphabet reverse))
1662
1663 (defun gnus-topic-sort-groups-by-unread (&optional reverse)
1664   "Sort the current topic by number of unread articles.
1665 If REVERSE, sort in reverse order."
1666   (interactive "P")
1667   (gnus-topic-sort-groups 'gnus-group-sort-by-unread reverse))
1668
1669 (defun gnus-topic-sort-groups-by-level (&optional reverse)
1670   "Sort the current topic by group level.
1671 If REVERSE, sort in reverse order."
1672   (interactive "P")
1673   (gnus-topic-sort-groups 'gnus-group-sort-by-level reverse))
1674
1675 (defun gnus-topic-sort-groups-by-score (&optional reverse)
1676   "Sort the current topic by group score.
1677 If REVERSE, sort in reverse order."
1678   (interactive "P")
1679   (gnus-topic-sort-groups 'gnus-group-sort-by-score reverse))
1680
1681 (defun gnus-topic-sort-groups-by-rank (&optional reverse)
1682   "Sort the current topic by group rank.
1683 If REVERSE, sort in reverse order."
1684   (interactive "P")
1685   (gnus-topic-sort-groups 'gnus-group-sort-by-rank reverse))
1686
1687 (defun gnus-topic-sort-groups-by-method (&optional reverse)
1688   "Sort the current topic alphabetically by backend name.
1689 If REVERSE, sort in reverse order."
1690   (interactive "P")
1691   (gnus-topic-sort-groups 'gnus-group-sort-by-method reverse))
1692
1693 (defun gnus-topic-sort-groups-by-server (&optional reverse)
1694   "Sort the current topic alphabetically by server name.
1695 If REVERSE, sort in reverse order."
1696   (interactive "P")
1697   (gnus-topic-sort-groups 'gnus-group-sort-by-server reverse))
1698
1699 (defun gnus-topic-sort-topics-1 (top reverse)
1700   (if (cdr top)
1701       (let ((subtop
1702              (mapcar (gnus-byte-compile
1703                       `(lambda (top)
1704                          (gnus-topic-sort-topics-1 top ,reverse)))
1705                      (sort (cdr top)
1706                            (lambda (t1 t2)
1707                              (string-lessp (caar t1) (caar t2)))))))
1708         (setcdr top (if reverse (reverse subtop) subtop))))
1709   top)
1710
1711 (defun gnus-topic-sort-topics (&optional topic reverse)
1712   "Sort topics in TOPIC alphabetically by topic name.
1713 If REVERSE, reverse the sorting order."
1714   (interactive
1715    (list (gnus-completing-read "Sort topics in"
1716                                (mapcar 'car gnus-topic-alist) t
1717                                (gnus-current-topic))
1718          current-prefix-arg))
1719   (let ((topic-topology (or (and topic (cdr (gnus-topic-find-topology topic)))
1720                             gnus-topic-topology)))
1721     (gnus-topic-sort-topics-1 topic-topology reverse)
1722     (gnus-topic-enter-dribble)
1723     (gnus-group-list-groups)
1724     (gnus-topic-goto-topic topic)))
1725
1726 (defun gnus-topic-move (current to)
1727   "Move the CURRENT topic to TO."
1728   (interactive
1729    (list
1730     (gnus-group-topic-name)
1731     (gnus-completing-read "Move to topic" (mapcar 'car gnus-topic-alist) t)))
1732   (unless (and current to)
1733     (error "Can't find topic"))
1734   (let ((current-top (cdr (gnus-topic-find-topology current)))
1735         (to-top (cdr (gnus-topic-find-topology to))))
1736     (unless current-top
1737       (error "Can't find topic `%s'" current))
1738     (unless to-top
1739       (error "Can't find topic `%s'" to))
1740     (if (gnus-topic-find-topology to current-top 0);; Don't care the level
1741         (error "Can't move `%s' to its sub-level" current))
1742     (gnus-topic-find-topology current nil nil 'delete)
1743     (setcdr (last to-top) (list current-top))
1744     (gnus-topic-enter-dribble)
1745     (gnus-group-list-groups)
1746     (gnus-topic-goto-topic current)))
1747
1748 (defun gnus-subscribe-topics (newsgroup)
1749   (catch 'end
1750     (let (match gnus-group-change-level-function)
1751       (dolist (topic (gnus-topic-list))
1752         (when (and (setq match (cdr (assq 'subscribe
1753                                           (gnus-topic-parameters topic))))
1754                    (string-match match newsgroup))
1755           ;; Just subscribe the group.
1756           (gnus-subscribe-alphabetically newsgroup)
1757           ;; Add the group to the topic.
1758           (nconc (assoc topic gnus-topic-alist) (list newsgroup))
1759           ;; if this topic specifies a default level, use it
1760           (let ((subscribe-level (cdr (assq 'subscribe-level
1761                                             (gnus-topic-parameters topic)))))
1762             (when subscribe-level
1763                 (gnus-group-change-level newsgroup subscribe-level
1764                                          gnus-level-default-subscribed)))
1765           (throw 'end t)))
1766       nil)))
1767
1768 (provide 'gnus-topic)
1769
1770 ;;; gnus-topic.el ends here