lisp/gnus/gnus-topic.el

   1 ;;; gnus-topic.el --- a folding minor mode for Gnus group buffers
   2
   3 ;; Copyright (C) 1995-2017 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 <http://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            (memq 'visible params)
 224            (cdr (assq 'visible params)))
 225        ;; Add this group to the list of visible groups.
 226        (push (or entry group) visible-groups)))
 227     (setq visible-groups (nreverse visible-groups))
 228     (when recursive
 229       (if (eq recursive t)
 230           (setq recursive (cdr (gnus-topic-find-topology topic))))
 231       (dolist (topic-topology (cdr recursive))
 232         (setq visible-groups
 233               (nconc visible-groups
 234                      (gnus-topic-find-groups
 235                       (caar topic-topology)
 236                       level all lowest topic-topology)))))
 237     visible-groups))
 238
 239 (defun gnus-topic-goto-previous-topic (n)
 240   "Go to the N'th previous topic."
 241   (interactive "p")
 242   (gnus-topic-goto-next-topic (- n)))
 243
 244 (defun gnus-topic-goto-next-topic (n)
 245   "Go to the N'th next topic."
 246   (interactive "p")
 247   (let ((backward (< n 0))
 248         (n (abs n))
 249         (topic (gnus-current-topic)))
 250     (while (and (> n 0)
 251                 (setq topic
 252                       (if backward
 253                           (gnus-topic-previous-topic topic)
 254                         (gnus-topic-next-topic topic))))
 255       (gnus-topic-goto-topic topic)
 256       (setq n (1- n)))
 257     (when (/= 0 n)
 258       (gnus-message 7 "No more topics"))
 259     n))
 260
 261 (defun gnus-topic-previous-topic (topic)
 262   "Return the previous topic on the same level as TOPIC."
 263   (let ((top (cddr (gnus-topic-find-topology
 264                     (gnus-topic-parent-topic topic)))))
 265     (unless (equal topic (caaar top))
 266       (while (and top (not (equal (caaadr top) topic)))
 267         (setq top (cdr top)))
 268       (caaar top))))
 269
 270 (defun gnus-topic-parent-topic (topic &optional topology)
 271   "Return the parent of TOPIC."
 272   (unless topology
 273     (setq topology gnus-topic-topology))
 274   (let ((parent (car (pop topology)))
 275         result found)
 276     (while (and topology
 277                 (not (setq found (equal (caaar topology) topic)))
 278                 (not (setq result (gnus-topic-parent-topic
 279                                    topic (car topology)))))
 280       (setq topology (cdr topology)))
 281     (or result (and found parent))))
 282
 283 (defun gnus-topic-next-topic (topic &optional previous)
 284   "Return the next sibling of TOPIC."
 285   (let ((parentt (cddr (gnus-topic-find-topology
 286                         (gnus-topic-parent-topic topic))))
 287         prev)
 288     (while (and parentt
 289                 (not (equal (caaar parentt) topic)))
 290       (setq prev (caaar parentt)
 291             parentt (cdr parentt)))
 292     (if previous
 293         prev
 294       (caaadr parentt))))
 295
 296 (defun gnus-topic-forward-topic (num)
 297   "Go to the next topic on the same level as the current one."
 298   (let* ((topic (gnus-current-topic))
 299          (way (if (< num 0) 'gnus-topic-previous-topic
 300                 'gnus-topic-next-topic))
 301          (num (abs num)))
 302     (while (and (not (zerop num))
 303                 (setq topic (funcall way topic)))
 304       (when (gnus-topic-goto-topic topic)
 305         (decf num)))
 306     (unless (zerop num)
 307       (goto-char (point-max)))
 308     num))
 309
 310 (defun gnus-topic-find-topology (topic &optional topology level remove)
 311   "Return the topology of TOPIC."
 312   (unless topology
 313     (setq topology gnus-topic-topology)
 314     (setq level 0))
 315   (let ((top topology)
 316         result)
 317     (if (equal (caar topology) topic)
 318         (progn
 319           (when remove
 320             (delq topology remove))
 321           (cons level topology))
 322       (setq topology (cdr topology))
 323       (while (and topology
 324                   (not (setq result (gnus-topic-find-topology
 325                                      topic (car topology) (1+ level)
 326                                      (and remove top)))))
 327         (setq topology (cdr topology)))
 328       result)))
 329
 330 (defvar gnus-tmp-topics nil)
 331 (defun gnus-topic-list (&optional topology)
 332   "Return a list of all topics in the topology."
 333   (unless topology
 334     (setq topology gnus-topic-topology
 335           gnus-tmp-topics nil))
 336   (push (caar topology) gnus-tmp-topics)
 337   (mapc 'gnus-topic-list (cdr topology))
 338   gnus-tmp-topics)
 339
 340 ;;; Topic parameter jazz
 341
 342 (defun gnus-topic-parameters (topic)
 343   "Return the parameters for TOPIC."
 344   (let ((top (gnus-topic-find-topology topic)))
 345     (when top
 346       (nth 3 (cadr top)))))
 347
 348 (defun gnus-topic-set-parameters (topic parameters)
 349   "Set the topic parameters of TOPIC to PARAMETERS."
 350   (let ((top (gnus-topic-find-topology topic)))
 351     (unless top
 352       (error "No such topic: %s" topic))
 353     ;; We may have to extend if there is no parameters here
 354     ;; to begin with.
 355     (unless (nthcdr 2 (cadr top))
 356       (nconc (cadr top) (list nil)))
 357     (unless (nthcdr 3 (cadr top))
 358       (nconc (cadr top) (list nil)))
 359     (setcar (nthcdr 3 (cadr top)) parameters)
 360     (gnus-dribble-enter
 361      (format "(gnus-topic-set-parameters %S '%S)" topic parameters))))
 362
 363 (defun gnus-group-topic-parameters (group)
 364   "Compute the group parameters for GROUP in topic mode.
 365 Possibly inherit parameters from topics above GROUP."
 366   (let ((params-list (copy-sequence (gnus-group-get-parameter group))))
 367     (save-excursion
 368       (gnus-topic-hierarchical-parameters
 369        ;; First we try to go to the group within the group buffer and find the
 370        ;; topic for the group that way. This hopefully copes well with groups
 371        ;; that are in more than one topic. Failing that (i.e. when the group
 372        ;; isn't visible in the group buffer) we find a topic for the group via
 373        ;; gnus-group-topic.
 374        (or (and (gnus-group-goto-group group)
 375                 (gnus-current-topic))
 376            (gnus-group-topic group))
 377        params-list))))
 378
 379 (defun gnus-topic-hierarchical-parameters (topic &optional group-params-list)
 380   "Compute the topic parameters for TOPIC.
 381 Possibly inherit parameters from topics above TOPIC.
 382 If optional argument GROUP-PARAMS-LIST is non-nil, use it as the basis for
 383 inheritance."
 384   (let ((params-list
 385          ;; We probably have lots of nil elements here, so we remove them.
 386          ;; Probably faster than doing this "properly".
 387          (delq nil (cons group-params-list
 388                          (mapcar 'gnus-topic-parameters
 389                                  (gnus-current-topics topic)))))
 390         param out params)
 391     ;; Now we have all the parameters, so we go through them
 392     ;; and do inheritance in the obvious way.
 393     (let (posting-style)
 394       (while (setq params (pop params-list))
 395         (while (setq param (pop params))
 396           (when (atom param)
 397             (setq param (cons param t)))
 398           (cond ((eq (car param) 'posting-style)
 399                  (let ((param (cdr param))
 400                        elt)
 401                    (while (setq elt (pop param))
 402                      (unless (assoc (car elt) posting-style)
 403                        (push elt posting-style)))))
 404                 (t
 405                  (unless (assq (car param) out)
 406                    (push param out))))))
 407       (and posting-style (push (cons 'posting-style posting-style) out)))
 408     ;; Return the resulting parameter list.
 409     out))
 410
 411 ;;; General utility functions
 412
 413 (defun gnus-topic-enter-dribble ()
 414   (gnus-dribble-enter
 415    (format "(setq gnus-topic-topology '%S)" gnus-topic-topology)))
 416
 417 ;;; Generating group buffers
 418
 419 (defun gnus-group-prepare-topics (level &optional predicate lowest
 420                                         regexp list-topic topic-level)
 421   "List all newsgroups with unread articles of level LEVEL or lower.
 422 Use the `gnus-group-topics' to sort the groups.
 423 If PREDICATE is a function, list groups that the function returns non-nil;
 424 if it is t, list groups that have no unread articles.
 425 If LOWEST is non-nil, list all newsgroups of level LOWEST or higher."
 426   (set-buffer gnus-group-buffer)
 427   (let ((inhibit-read-only t)
 428         (lowest (or lowest 1))
 429         (not-in-list
 430          (and gnus-group-listed-groups
 431               (copy-sequence gnus-group-listed-groups))))
 432
 433     (gnus-update-format-specifications nil 'topic)
 434
 435     (when (or (not gnus-topic-alist)
 436               (not gnus-topology-checked-p))
 437       (gnus-topic-check-topology))
 438
 439     (unless list-topic
 440       (erase-buffer))
 441
 442     ;; List dead groups?
 443     (when (or gnus-group-listed-groups
 444               (and (>= level gnus-level-zombie)
 445                    (<= lowest gnus-level-zombie)))
 446       (gnus-group-prepare-flat-list-dead
 447        (setq gnus-zombie-list (sort gnus-zombie-list 'string<))
 448        gnus-level-zombie ?Z
 449        regexp))
 450
 451     (when (or gnus-group-listed-groups
 452                (and (>= level gnus-level-killed)
 453                     (<= lowest gnus-level-killed)))
 454       (gnus-group-prepare-flat-list-dead
 455        (setq gnus-killed-list (sort gnus-killed-list 'string<))
 456        gnus-level-killed ?K regexp)
 457       (when not-in-list
 458         (unless gnus-killed-hashtb
 459           (gnus-make-hashtable-from-killed))
 460         (gnus-group-prepare-flat-list-dead
 461          (gnus-remove-if (lambda (group)
 462                            (or (gnus-group-entry group)
 463                                (gnus-gethash group gnus-killed-hashtb)))
 464                          not-in-list)
 465          gnus-level-killed ?K regexp)))
 466
 467     ;; Use topics.
 468     (prog1
 469         (when (or (< lowest gnus-level-zombie)
 470                   gnus-group-listed-groups)
 471           (if list-topic
 472               (let ((top (gnus-topic-find-topology list-topic)))
 473                 (gnus-topic-prepare-topic (cdr top) (car top)
 474                                           (or topic-level level) predicate
 475                                           nil lowest regexp))
 476             (gnus-topic-prepare-topic gnus-topic-topology 0
 477                                       (or topic-level level) predicate
 478                                       nil lowest regexp)))
 479       (gnus-group-set-mode-line)
 480       (setq gnus-group-list-mode (cons level predicate))
 481       (gnus-run-hooks 'gnus-group-prepare-hook))))
 482
 483 (defun gnus-topic-prepare-topic (topicl level &optional list-level
 484                                         predicate silent
 485                                         lowest regexp)
 486   "Insert TOPIC into the group buffer.
 487 If SILENT, don't insert anything.  Return the number of unread
 488 articles in the topic and its subtopics."
 489   (let* ((type (pop topicl))
 490          (entries (gnus-topic-find-groups
 491                    (car type)
 492                    (if gnus-group-listed-groups
 493                        gnus-level-killed
 494                      list-level)
 495                    (or predicate gnus-group-listed-groups
 496                        (cdr (assq 'visible
 497                                   (gnus-topic-hierarchical-parameters
 498                                    (car type)))))
 499                    (if gnus-group-listed-groups 0 lowest)))
 500          (visiblep (and (eq (nth 1 type) 'visible) (not silent)))
 501          (gnus-group-indentation
 502           (make-string (* gnus-topic-indent-level level) ? ))
 503          (beg (progn (beginning-of-line) (point)))
 504          (topicl (reverse topicl))
 505          (all-entries entries)
 506          (point-max (point-max))
 507          (unread 0)
 508          info entry end active tick)
 509     ;; Insert any sub-topics.
 510     (while topicl
 511       (incf unread
 512             (gnus-topic-prepare-topic
 513              (pop topicl) (1+ level) list-level predicate
 514              (not visiblep) lowest regexp)))
 515     (setq end (point))
 516     (goto-char beg)
 517     ;; Insert all the groups that belong in this topic.
 518     (while (setq entry (pop entries))
 519       (when (if (stringp entry)
 520                 (gnus-group-prepare-logic
 521                  entry
 522                  (and
 523                   (or (not gnus-group-listed-groups)
 524                       (if (< list-level gnus-level-zombie) nil
 525                         (let ((entry-level
 526                                (if (member entry gnus-zombie-list)
 527                                    gnus-level-zombie gnus-level-killed)))
 528                           (and (<= entry-level list-level)
 529                                (>= entry-level lowest)))))
 530                   (cond
 531                    ((stringp regexp)
 532                     (string-match regexp entry))
 533                    ((functionp regexp)
 534                     (funcall regexp entry))
 535                    ((null regexp) t)
 536                    (t nil))))
 537               (setq info (nth 2 entry))
 538               (gnus-group-prepare-logic
 539                (gnus-info-group info)
 540                (and (or (not gnus-group-listed-groups)
 541                         (let ((entry-level (gnus-info-level info)))
 542                           (and (<= entry-level list-level)
 543                                (>= entry-level lowest))))
 544                     (or (not (functionp predicate))
 545                         (funcall predicate info))
 546                     (or (not (stringp regexp))
 547                         (string-match regexp (gnus-info-group info))))))
 548         (when visiblep
 549           (if (stringp entry)
 550               ;; Dead groups.
 551               (gnus-group-insert-group-line
 552                entry (if (member entry gnus-zombie-list)
 553                          gnus-level-zombie gnus-level-killed)
 554                nil (- (1+ (cdr (setq active (gnus-active entry))))
 555                       (car active))
 556                nil)
 557             ;; Living groups.
 558             (when (setq info (nth 2 entry))
 559               (gnus-group-insert-group-line
 560                (gnus-info-group info)
 561                (gnus-info-level info) (gnus-info-marks info)
 562                (car entry) (gnus-info-method info)))))
 563         (when (and (listp entry)
 564                    (numberp (car entry)))
 565           (incf unread (car entry)))
 566         (when (listp entry)
 567           (setq tick t))))
 568     (goto-char beg)
 569     ;; Insert the topic line.
 570     (when (and (not silent)
 571                (or gnus-topic-display-empty-topics ;We want empty topics
 572                    (not (zerop unread)) ;Non-empty
 573                    tick                 ;Ticked articles
 574                    (/= point-max (point-max)))) ;Inactive groups
 575       (gnus-topic-insert-topic-line
 576        (car type) visiblep
 577        (not (eq (nth 2 type) 'hidden))
 578        level all-entries unread))
 579     (gnus-topic-update-unreads (car type) unread)
 580     (gnus-group--setup-tool-bar-update beg end)
 581     (goto-char end)
 582     unread))
 583
 584 (defun gnus-topic-remove-topic (&optional insert total-remove _hide in-level)
 585   "Remove the current topic."
 586   (let ((topic (gnus-group-topic-name))
 587         (level (gnus-group-topic-level))
 588         (beg (progn (beginning-of-line) (point)))
 589         buffer-read-only)
 590     (when topic
 591       (while (and (zerop (forward-line 1))
 592                   (> (or (gnus-group-topic-level) (1+ level)) level)))
 593       (delete-region beg (point))
 594       ;; Do the change in this rather odd manner because it has been
 595       ;; reported that some topics share parts of some lists, for some
 596       ;; reason.  I have been unable to determine why this is the
 597       ;; case, but this hack seems to take care of things.
 598       (let ((data (cadr (gnus-topic-find-topology topic))))
 599         (setcdr data
 600                 (list (if insert 'visible 'invisible)
 601                       (caddr data)
 602                       (cadddr data))))
 603       (if total-remove
 604           (setq gnus-topic-alist
 605                 (delq (assoc topic gnus-topic-alist) gnus-topic-alist))
 606         (gnus-topic-insert-topic topic in-level)))))
 607
 608 (defun gnus-topic-insert-topic (topic &optional level)
 609   "Insert TOPIC."
 610   (gnus-group-prepare-topics
 611    (car gnus-group-list-mode) (cdr gnus-group-list-mode)
 612    nil nil topic level))
 613
 614 (defun gnus-topic-fold (&optional insert topic)
 615   "Remove/insert the current topic."
 616   (let ((topic (or topic (gnus-group-topic-name))))
 617     (when topic
 618       (save-excursion
 619         (if (not (gnus-group-active-topic-p))
 620             (gnus-topic-remove-topic
 621              (or insert (not (gnus-topic-visible-p))))
 622           (let ((gnus-topic-topology gnus-topic-active-topology)
 623                 (gnus-topic-alist gnus-topic-active-alist)
 624                 (gnus-group-list-mode (cons 5 t)))
 625             (gnus-topic-remove-topic
 626              (or insert (not (gnus-topic-visible-p))) nil nil 9)
 627             (gnus-topic-enter-dribble)))))))
 628
 629 (defvar gnus-tmp-header)
 630
 631 (defun gnus-topic-insert-topic-line (name visiblep shownp level entries
 632                                           &optional unread)
 633   (let* ((visible (if visiblep "" "..."))
 634          (indentation (make-string (* gnus-topic-indent-level level) ? ))
 635          (total-number-of-articles unread)
 636          (number-of-groups (length entries))
 637          (active-topic (eq gnus-topic-alist gnus-topic-active-alist))
 638          gnus-tmp-header)
 639     (gnus-topic-update-unreads name unread)
 640     (beginning-of-line)
 641     ;; Insert the text.
 642     (if shownp
 643         (add-text-properties
 644          (point)
 645          (prog1 (1+ (point))
 646            (eval gnus-topic-line-format-spec))
 647          (list 'gnus-topic (intern name)
 648                'gnus-topic-level level
 649                'gnus-topic-unread unread
 650                'gnus-active active-topic
 651                'gnus-topic-visible visiblep)))))
 652
 653 (defun gnus-topic-update-unreads (topic unreads)
 654   (setq gnus-topic-unreads (delq (assoc topic gnus-topic-unreads)
 655                                  gnus-topic-unreads))
 656   (push (cons topic unreads) gnus-topic-unreads))
 657
 658 (defun gnus-topic-update-topics-containing-group (group)
 659   "Update all topics that have GROUP as a member."
 660   (when (and (eq major-mode 'gnus-group-mode)
 661              gnus-topic-mode)
 662     (save-excursion
 663       (let ((alist gnus-topic-alist))
 664         ;; This is probably not entirely correct.  If a topic
 665         ;; isn't shown, then it's not updated.  But the updating
 666         ;; should be performed in any case, since the topic's
 667         ;; parent should be updated.  Pfft.
 668         (while alist
 669           (when (and (member group (cdar alist))
 670                      (gnus-topic-goto-topic (caar alist)))
 671             (gnus-topic-update-topic-line (caar alist)))
 672           (pop alist))))))
 673
 674 (defun gnus-topic-update-topic ()
 675   "Update all parent topics to the current group."
 676   (when (and (eq major-mode 'gnus-group-mode)
 677              gnus-topic-mode)
 678     (let ((group (gnus-group-group-name))
 679           (m (point-marker))
 680           (inhibit-read-only t))
 681       (when (and group
 682                  (gnus-get-info group)
 683                  (gnus-topic-goto-topic (gnus-current-topic)))
 684         (gnus-topic-update-topic-line (gnus-group-topic-name))
 685         (goto-char m)
 686         (set-marker m nil)
 687         (gnus-group-position-point)))))
 688
 689 (defun gnus-topic-goto-missing-group (group)
 690   "Place point where GROUP is supposed to be inserted."
 691   (let* ((topic (gnus-group-topic group))
 692          (groups (cdr (assoc topic gnus-topic-alist)))
 693          (g (cdr (member group groups)))
 694          (unfound t))
 695     ;; Try to jump to a visible group.
 696     (while (and g
 697                 (not (gnus-group-goto-group (car g) t)))
 698       (pop g))
 699     ;; It wasn't visible, so we try to see where to insert it.
 700     (when (not g)
 701       (setq g (cdr (member group (reverse groups))))
 702       (while (and g unfound)
 703         (when (gnus-group-goto-group (pop g) t)
 704           (forward-line 1)
 705           (setq unfound nil)))
 706       (when (and unfound
 707                  topic
 708                  (not (gnus-topic-goto-missing-topic topic)))
 709         (gnus-topic-display-missing-topic topic)))))
 710
 711 (defun gnus-topic-display-missing-topic (topic)
 712   "Insert topic lines recursively for missing topics."
 713   (let ((parent (gnus-topic-find-topology
 714                  (gnus-topic-parent-topic topic))))
 715     (when (and parent
 716                (not (gnus-topic-goto-missing-topic (caadr parent))))
 717       (gnus-topic-display-missing-topic (caadr parent))))
 718   (gnus-topic-goto-missing-topic topic)
 719   ;; Skip past all groups in the topic we're in.
 720   (while (gnus-group-group-name)
 721     (forward-line 1))
 722   (let* ((top (gnus-topic-find-topology topic))
 723          (children (cddr top))
 724          (type (cadr top))
 725          (unread 0)
 726          (entries (gnus-topic-find-groups
 727                    (car type) (car gnus-group-list-mode)
 728                    (cdr gnus-group-list-mode)))
 729         entry)
 730     (while children
 731       (incf unread (gnus-topic-unread (caar (pop children)))))
 732     (while (setq entry (pop entries))
 733       (when (numberp (car entry))
 734         (incf unread (car entry))))
 735     (gnus-topic-insert-topic-line
 736      topic t t (car (gnus-topic-find-topology topic)) nil unread)))
 737
 738 (defun gnus-topic-goto-missing-topic (topic)
 739   (if (gnus-topic-goto-topic topic)
 740       (forward-line 1)
 741     ;; Topic not displayed.
 742     (let* ((top (gnus-topic-find-topology
 743                  (gnus-topic-parent-topic topic)))
 744            (tp (reverse (cddr top))))
 745       (if (not top)
 746           (gnus-topic-insert-topic-line
 747            topic t t (car (gnus-topic-find-topology topic)) nil 0)
 748         (while (not (equal (caaar tp) topic))
 749           (setq tp (cdr tp)))
 750         (pop tp)
 751         (while (and tp
 752                     (not (gnus-topic-goto-topic (caaar tp))))
 753           (pop tp))
 754         (if tp
 755             (gnus-topic-forward-topic 1)
 756           (gnus-topic-goto-missing-topic (caadr top)))))
 757     nil))
 758
 759 (defun gnus-topic-update-topic-line (topic-name &optional reads)
 760   (let* ((top (gnus-topic-find-topology topic-name))
 761          (type (cadr top))
 762          (children (cddr top))
 763          (entries (gnus-topic-find-groups
 764                    (car type) (car gnus-group-list-mode)
 765                    (cdr gnus-group-list-mode)))
 766          (parent (gnus-topic-parent-topic topic-name))
 767          (all-entries entries)
 768          (unread 0)
 769          old-unread entry new-unread)
 770     (when (gnus-topic-goto-topic (car type))
 771       ;; Tally all the groups that belong in this topic.
 772       (if reads
 773           (setq unread (- (gnus-group-topic-unread) reads))
 774         (while children
 775           (incf unread (gnus-topic-unread (caar (pop children)))))
 776         (while (setq entry (pop entries))
 777           (when (numberp (car entry))
 778             (incf unread (car entry)))))
 779       (setq old-unread (gnus-group-topic-unread))
 780       ;; Insert the topic line.
 781       (gnus-topic-insert-topic-line
 782        (car type) (gnus-topic-visible-p)
 783        (not (eq (nth 2 type) 'hidden))
 784        (gnus-group-topic-level) all-entries unread)
 785       (gnus-delete-line)
 786       (forward-line -1)
 787       (setq new-unread (gnus-group-topic-unread)))
 788     (when parent
 789       (forward-line -1)
 790       (gnus-topic-update-topic-line
 791        parent
 792        (- (or old-unread 0) (or new-unread 0))))
 793     unread))
 794
 795 (defun gnus-topic-group-indentation ()
 796   (make-string
 797    (* gnus-topic-indent-level
 798       (or (save-excursion
 799             (forward-line -1)
 800             (gnus-topic-goto-topic (gnus-current-topic))
 801             (gnus-group-topic-level))
 802           0))
 803    ? ))
 804
 805 ;;; Initialization
 806
 807 (gnus-add-shutdown 'gnus-topic-close 'gnus)
 808
 809 (defun gnus-topic-close ()
 810   (setq gnus-topic-active-topology nil
 811         gnus-topic-active-alist nil
 812         gnus-topic-killed-topics nil
 813         gnus-topology-checked-p nil))
 814
 815 (defun gnus-topic-check-topology ()
 816   ;; The first time we set the topology to whatever we have
 817   ;; gotten here, which can be rather random.
 818   (unless gnus-topic-alist
 819     (gnus-topic-init-alist))
 820
 821   (setq gnus-topology-checked-p t)
 822   ;; Go through the topic alist and make sure that all topics
 823   ;; are in the topic topology.
 824   (let ((topics (gnus-topic-list))
 825         (alist gnus-topic-alist)
 826         changed)
 827     (while alist
 828       (unless (member (caar alist) topics)
 829         (nconc gnus-topic-topology
 830                (list (list (list (caar alist) 'visible))))
 831         (setq changed t))
 832       (setq alist (cdr alist)))
 833     (when changed
 834       (gnus-topic-enter-dribble))
 835     ;; Conversely, go through the topology and make sure that all
 836     ;; topologies have alists.
 837     (while topics
 838       (unless (assoc (car topics) gnus-topic-alist)
 839         (push (list (car topics)) gnus-topic-alist))
 840       (pop topics)))
 841   ;; Go through all living groups and make sure that
 842   ;; they belong to some topic.
 843   (let* ((tgroups (apply 'append (mapcar 'cdr gnus-topic-alist)))
 844          (entry (last (assoc (caar gnus-topic-topology) gnus-topic-alist)))
 845          (newsrc (cdr gnus-newsrc-alist))
 846          group)
 847     (while newsrc
 848       (unless (member (setq group (gnus-info-group (pop newsrc))) tgroups)
 849         (setcdr entry (list group))
 850         (setq entry (cdr entry)))))
 851   ;; Go through all topics and make sure they contain only living groups.
 852   (let ((alist gnus-topic-alist)
 853         topic)
 854     (while (setq topic (pop alist))
 855       (while (cdr topic)
 856         (if (and (cadr topic)
 857                  (gnus-group-entry (cadr topic)))
 858             (setq topic (cdr topic))
 859           (setcdr topic (cddr topic)))))))
 860
 861 (defun gnus-topic-init-alist ()
 862   "Initialize the topic structures."
 863   (setq gnus-topic-topology
 864         (cons (list "Gnus" 'visible)
 865               (mapcar (lambda (topic)
 866                         (list (list (car topic) 'visible)))
 867                       '(("misc")))))
 868   (setq gnus-topic-alist
 869         (list (cons "misc"
 870                     (mapcar (lambda (info) (gnus-info-group info))
 871                             (cdr gnus-newsrc-alist)))
 872               (list "Gnus")))
 873   (gnus-topic-enter-dribble))
 874
 875 ;;; Maintenance
 876
 877 (defun gnus-topic-clean-alist ()
 878   "Remove bogus groups from the topic alist."
 879   (let ((topic-alist gnus-topic-alist)
 880         result topic)
 881     (unless gnus-killed-hashtb
 882       (gnus-make-hashtable-from-killed))
 883     (while (setq topic (pop topic-alist))
 884       (let ((topic-name (pop topic))
 885             group filtered-topic)
 886         (while (setq group (pop topic))
 887           (when (and (or (gnus-active group)
 888                          (gnus-info-method (gnus-get-info group)))
 889                      (not (gnus-gethash group gnus-killed-hashtb)))
 890             (push group filtered-topic)))
 891         (push (cons topic-name (nreverse filtered-topic)) result)))
 892     (setq gnus-topic-alist (nreverse result))))
 893
 894 (defun gnus-topic-change-level (group level oldlevel &optional previous)
 895   "Run when changing levels to enter/remove groups from topics."
 896   (with-current-buffer gnus-group-buffer
 897     (let ((inhibit-read-only t))
 898       (unless gnus-topic-inhibit-change-level
 899         (gnus-group-goto-group (or (car (nth 2 previous)) group))
 900         (when (and gnus-topic-mode
 901                    gnus-topic-alist
 902                    (not gnus-topic-inhibit-change-level))
 903           ;; Remove the group from the topics.
 904           (if (and (< oldlevel gnus-level-zombie)
 905                    (>= level gnus-level-zombie))
 906               (let ((alist gnus-topic-alist))
 907                 (while (gnus-group-goto-group group)
 908                   (gnus-delete-line))
 909                 (while alist
 910                   (when (member group (car alist))
 911                     (setcdr (car alist) (delete group (cdar alist))))
 912                   (pop alist)))
 913             ;; If the group is subscribed we enter it into the topics.
 914             (when (and (< level gnus-level-zombie)
 915                        (>= oldlevel gnus-level-zombie))
 916               (let* ((prev (gnus-group-group-name))
 917                      (gnus-topic-inhibit-change-level t)
 918                      (gnus-group-indentation
 919                       (make-string
 920                        (* gnus-topic-indent-level
 921                           (or (save-excursion
 922                                 (gnus-topic-goto-topic (gnus-current-topic))
 923                                 (gnus-group-topic-level))
 924                               0))
 925                        ? ))
 926                      (yanked (list group))
 927                      alist talist end)
 928                 ;; Then we enter the yanked groups into the topics
 929                 ;; they belong to.
 930                 (when (setq alist (assoc (save-excursion
 931                                            (forward-line -1)
 932                                            (or
 933                                             (gnus-current-topic)
 934                                             (caar gnus-topic-topology)))
 935                                          gnus-topic-alist))
 936                   (setq talist alist)
 937                   (when (stringp yanked)
 938                     (setq yanked (list yanked)))
 939                   (if (not prev)
 940                       (nconc alist yanked)
 941                     (if (not (cdr alist))
 942                         (setcdr alist (nconc yanked (cdr alist)))
 943                       (while (and (not end) (cdr alist))
 944                         (when (equal (cadr alist) prev)
 945                           (setcdr alist (nconc yanked (cdr alist)))
 946                           (setq end t))
 947                         (setq alist (cdr alist)))
 948                       (unless end
 949                         (nconc talist yanked))))))
 950               (gnus-topic-update-topic))))))))
 951
 952 (defun gnus-topic-goto-next-group (group props)
 953   "Go to group or the next group after group."
 954   (if (not group)
 955       (if (not (memq 'gnus-topic props))
 956           (goto-char (point-max))
 957         (let ((topic (symbol-name (cadr (memq 'gnus-topic props)))))
 958           (or (gnus-topic-goto-topic topic)
 959               (gnus-topic-goto-topic (gnus-topic-next-topic topic)))))
 960     (if (gnus-group-goto-group group)
 961         t
 962       ;; The group is no longer visible.
 963       (let* ((list (assoc (gnus-group-topic group) gnus-topic-alist))
 964              (topic-visible (save-excursion (gnus-topic-goto-topic (car list))))
 965              (after (and topic-visible (cdr (member group (cdr list))))))
 966         ;; First try to put point on a group after the current one.
 967         (while (and after
 968                     (not (gnus-group-goto-group (car after))))
 969           (setq after (cdr after)))
 970         ;; Then try to put point on a group before point.
 971         (unless after
 972           (setq after (cdr (member group (reverse (cdr list)))))
 973           (while (and after
 974                       (not (gnus-group-goto-group (car after))))
 975             (setq after (cdr after))))
 976         ;; Finally, just put point on the topic.
 977         (if (not (car list))
 978             (goto-char (point-min))
 979           (unless after
 980             (if topic-visible
 981                 (gnus-goto-char topic-visible)
 982               (gnus-topic-goto-topic (gnus-topic-next-topic (car list))))
 983             (setq after nil)))
 984         t))))
 985
 986 ;;; Topic-active functions
 987
 988 (defun gnus-topic-grok-active (&optional force)
 989   "Parse all active groups and create topic structures for them."
 990   ;; First we make sure that we have really read the active file.
 991   (when (or force
 992             (not gnus-topic-active-alist))
 993     (let (groups)
 994       ;; Get a list of all groups available.
 995       (mapatoms (lambda (g) (when (symbol-value g)
 996                               (push (symbol-name g) groups)))
 997                 gnus-active-hashtb)
 998       (setq groups (sort groups 'string<))
 999       ;; Init the variables.
1000       (setq gnus-topic-active-topology (list (list "" 'visible)))
1001       (setq gnus-topic-active-alist nil)
1002       ;; Descend the top-level hierarchy.
1003       (gnus-topic-grok-active-1 gnus-topic-active-topology groups)
1004       ;; Set the top-level topic names to something nice.
1005       (setcar (car gnus-topic-active-topology) "Gnus active")
1006       (setcar (car gnus-topic-active-alist) "Gnus active"))))
1007
1008 (defun gnus-topic-grok-active-1 (topology groups)
1009   (let* ((name (caar topology))
1010          (prefix (concat "^" (regexp-quote name)))
1011          tgroups ntopology group)
1012     (while (and groups
1013                 (string-match prefix (setq group (car groups))))
1014       (if (not (string-match "\\." group (match-end 0)))
1015           ;; There are no further hierarchies here, so we just
1016           ;; enter this group into the list belonging to this
1017           ;; topic.
1018           (push (pop groups) tgroups)
1019         ;; New sub-hierarchy, so we add it to the topology.
1020         (nconc topology (list (setq ntopology
1021                                     (list (list (substring
1022                                                  group 0 (match-end 0))
1023                                                 'invisible)))))
1024         ;; Descend the hierarchy.
1025         (setq groups (gnus-topic-grok-active-1 ntopology groups))))
1026     ;; We remove the trailing "." from the topic name.
1027     (setq name
1028           (if (string-match "\\.$" name)
1029               (substring name 0 (match-beginning 0))
1030             name))
1031     ;; Add this topic and its groups to the topic alist.
1032     (push (cons name (nreverse tgroups)) gnus-topic-active-alist)
1033     (setcar (car topology) name)
1034     ;; We return the rest of the groups that didn't belong
1035     ;; to this topic.
1036     groups))
1037
1038 ;;; Topic mode, commands and keymap.
1039
1040 (defvar gnus-topic-mode-map nil)
1041 (defvar gnus-group-topic-map nil)
1042
1043 (unless gnus-topic-mode-map
1044   (setq gnus-topic-mode-map (make-sparse-keymap))
1045
1046   ;; Override certain group mode keys.
1047   (gnus-define-keys gnus-topic-mode-map
1048     "=" gnus-topic-select-group
1049     "\r" gnus-topic-select-group
1050     " " gnus-topic-read-group
1051     "\C-c\C-x" gnus-topic-expire-articles
1052     "c" gnus-topic-catchup-articles
1053     "\C-k" gnus-topic-kill-group
1054     "\C-y" gnus-topic-yank-group
1055     "\M-g" gnus-topic-get-new-news-this-topic
1056     "AT" gnus-topic-list-active
1057     "Gp" gnus-topic-edit-parameters
1058     "#" gnus-topic-mark-topic
1059     "\M-#" gnus-topic-unmark-topic
1060     [tab] gnus-topic-indent
1061     [(meta tab)] gnus-topic-unindent
1062     "\C-i" gnus-topic-indent
1063     "\M-\C-i" gnus-topic-unindent
1064     [mouse-2] gnus-mouse-pick-topic)
1065
1066   ;; Define a new submap.
1067   (gnus-define-keys (gnus-group-topic-map "T" gnus-group-mode-map)
1068     "#" gnus-topic-mark-topic
1069     "\M-#" gnus-topic-unmark-topic
1070     "n" gnus-topic-create-topic
1071     "m" gnus-topic-move-group
1072     "D" gnus-topic-remove-group
1073     "c" gnus-topic-copy-group
1074     "h" gnus-topic-hide-topic
1075     "s" gnus-topic-show-topic
1076     "j" gnus-topic-jump-to-topic
1077     "M" gnus-topic-move-matching
1078     "C" gnus-topic-copy-matching
1079     "\M-p" gnus-topic-goto-previous-topic
1080     "\M-n" gnus-topic-goto-next-topic
1081     "\C-i" gnus-topic-indent
1082     [tab] gnus-topic-indent
1083     "r" gnus-topic-rename
1084     "\177" gnus-topic-delete
1085     [delete] gnus-topic-delete
1086     "H" gnus-topic-toggle-display-empty-topics)
1087
1088   (gnus-define-keys (gnus-topic-sort-map "S" gnus-group-topic-map)
1089     "s" gnus-topic-sort-groups
1090     "a" gnus-topic-sort-groups-by-alphabet
1091     "u" gnus-topic-sort-groups-by-unread
1092     "l" gnus-topic-sort-groups-by-level
1093     "e" gnus-topic-sort-groups-by-server
1094     "v" gnus-topic-sort-groups-by-score
1095     "r" gnus-topic-sort-groups-by-rank
1096     "m" gnus-topic-sort-groups-by-method))
1097
1098 (defun gnus-topic-make-menu-bar ()
1099   (unless (boundp 'gnus-topic-menu)
1100     (easy-menu-define
1101      gnus-topic-menu gnus-topic-mode-map ""
1102      '("Topics"
1103        ["Toggle topics" gnus-topic-mode t]
1104        ("Groups"
1105         ["Copy..." gnus-topic-copy-group t]
1106         ["Move..." gnus-topic-move-group t]
1107         ["Remove" gnus-topic-remove-group t]
1108         ["Copy matching..." gnus-topic-copy-matching t]
1109         ["Move matching..." gnus-topic-move-matching t])
1110        ("Topics"
1111         ["Goto..." gnus-topic-jump-to-topic t]
1112         ["Show" gnus-topic-show-topic t]
1113         ["Hide" gnus-topic-hide-topic t]
1114         ["Delete" gnus-topic-delete t]
1115         ["Rename..." gnus-topic-rename t]
1116         ["Create..." gnus-topic-create-topic t]
1117         ["Mark" gnus-topic-mark-topic t]
1118         ["Indent" gnus-topic-indent t]
1119         ["Sort" gnus-topic-sort-topics t]
1120         ["Previous topic" gnus-topic-goto-previous-topic t]
1121         ["Next topic" gnus-topic-goto-next-topic t]
1122         ["Toggle hide empty" gnus-topic-toggle-display-empty-topics t]
1123         ["Edit parameters" gnus-topic-edit-parameters t])
1124        ["List active" gnus-topic-list-active t]))))
1125
1126 (define-minor-mode gnus-topic-mode
1127   "Minor mode for topicsifying Gnus group buffers."
1128   :lighter " Topic" :keymap gnus-topic-mode-map
1129   (if (not (derived-mode-p 'gnus-group-mode))
1130       (setq gnus-topic-mode nil)
1131     ;; Infest Gnus with topics.
1132     (if (not gnus-topic-mode)
1133         (setq gnus-goto-missing-group-function nil)
1134       (when (gnus-visual-p 'topic-menu 'menu)
1135         (gnus-topic-make-menu-bar))
1136       (gnus-set-format 'topic t)
1137       (add-hook 'gnus-group-catchup-group-hook 'gnus-topic-update-topic)
1138       (set (make-local-variable 'gnus-group-prepare-function)
1139            'gnus-group-prepare-topics)
1140       (set (make-local-variable 'gnus-group-get-parameter-function)
1141            'gnus-group-topic-parameters)
1142       (set (make-local-variable 'gnus-group-goto-next-group-function)
1143            'gnus-topic-goto-next-group)
1144       (set (make-local-variable 'gnus-group-indentation-function)
1145            'gnus-topic-group-indentation)
1146       (set (make-local-variable 'gnus-group-update-group-function)
1147            'gnus-topic-update-topics-containing-group)
1148       (set (make-local-variable 'gnus-group-sort-alist-function)
1149            'gnus-group-sort-topic)
1150       (setq gnus-group-change-level-function 'gnus-topic-change-level)
1151       (setq gnus-goto-missing-group-function 'gnus-topic-goto-missing-group)
1152       (add-hook 'gnus-check-bogus-groups-hook 'gnus-topic-clean-alist
1153                 nil 'local)
1154       (setq gnus-topology-checked-p nil)
1155       ;; We check the topology.
1156       (when gnus-newsrc-alist
1157         (gnus-topic-check-topology)))
1158     ;; Remove topic infestation.
1159     (unless gnus-topic-mode
1160       (remove-hook 'gnus-summary-exit-hook 'gnus-topic-update-topic)
1161       (setq gnus-group-change-level-function nil)
1162       (remove-hook 'gnus-check-bogus-groups-hook 'gnus-topic-clean-alist)
1163       (setq gnus-group-prepare-function 'gnus-group-prepare-flat)
1164       (setq gnus-group-sort-alist-function 'gnus-group-sort-flat))
1165     (when (called-interactively-p 'any)
1166       (gnus-group-list-groups))))
1167
1168 (defun gnus-topic-select-group (&optional all)
1169   "Select this newsgroup.
1170 No article is selected automatically.
1171 If the group is opened, just switch the summary buffer.
1172 If ALL is non-nil, already read articles become readable.
1173
1174 If ALL is a positive number, fetch this number of the latest
1175 articles in the group.  If ALL is a negative number, fetch this
1176 number of the earliest articles in the group.
1177
1178 If performed over a topic line, toggle folding the topic."
1179   (interactive "P")
1180   (when (and (eobp) (not (gnus-group-group-name)))
1181     (forward-line -1))
1182   (if (gnus-group-topic-p)
1183       (let ((gnus-group-list-mode
1184              (if all (cons (if (numberp all) all 7) t) gnus-group-list-mode)))
1185         (gnus-topic-fold all)
1186         (gnus-dribble-touch))
1187     (gnus-group-select-group all)))
1188
1189 (defun gnus-mouse-pick-topic (e)
1190   "Select the group or topic under the mouse pointer."
1191   (interactive "e")
1192   (mouse-set-point e)
1193   (gnus-topic-read-group nil))
1194
1195 (defun gnus-topic-expire-articles (topic)
1196   "Expire articles in this topic or group."
1197   (interactive (list (gnus-group-topic-name)))
1198   (if (not topic)
1199       (call-interactively 'gnus-group-expire-articles)
1200     (save-excursion
1201       (gnus-message 5 "Expiring groups in %s..." topic)
1202       (let ((gnus-group-marked
1203              (mapcar (lambda (entry) (car (nth 2 entry)))
1204                      (gnus-topic-find-groups topic gnus-level-killed t
1205                                              nil t))))
1206         (gnus-group-expire-articles nil))
1207       (gnus-message 5 "Expiring groups in %s...done" topic))))
1208
1209 (defun gnus-topic-catchup-articles (topic)
1210   "Catchup this topic or group.
1211 Also see `gnus-group-catchup'."
1212   (interactive (list (gnus-group-topic-name)))
1213   (if (not topic)
1214       (call-interactively 'gnus-group-catchup-current)
1215     (save-excursion
1216       (let* ((groups
1217               (mapcar (lambda (entry) (car (nth 2 entry)))
1218                       (gnus-topic-find-groups topic gnus-level-killed t
1219                                               nil t)))
1220              (inhibit-read-only t)
1221              (gnus-group-marked groups))
1222         (gnus-group-catchup-current)
1223         (mapcar 'gnus-topic-update-topics-containing-group groups)))))
1224
1225 (defun gnus-topic-read-group (&optional all no-article group)
1226   "Read news in this newsgroup.
1227 If the prefix argument ALL is non-nil, already read articles become
1228 readable.
1229
1230 If ALL is a positive number, fetch this number of the latest
1231 articles in the group.  If ALL is a negative number, fetch this
1232 number of the earliest articles in the group.
1233
1234 If the optional argument NO-ARTICLE is non-nil, no article will
1235 be auto-selected upon group entry.  If GROUP is non-nil, fetch
1236 that group.
1237
1238 If performed over a topic line, toggle folding the topic."
1239   (interactive "P")
1240   (when (and (eobp) (not (gnus-group-group-name)))
1241     (forward-line -1))
1242   (if (gnus-group-topic-p)
1243       (let ((gnus-group-list-mode
1244              (if all (cons (if (numberp all) all 7) t) gnus-group-list-mode)))
1245         (gnus-topic-fold all))
1246     (gnus-group-read-group all no-article group)))
1247
1248 (defun gnus-topic-create-topic (topic parent &optional previous full-topic)
1249   "Create a new TOPIC under PARENT.
1250 When used interactively, PARENT will be the topic under point."
1251   (interactive
1252    (list
1253     (read-string "New topic: ")
1254     (gnus-current-topic)))
1255   ;; Check whether this topic already exists.
1256   (when (gnus-topic-find-topology topic)
1257     (error "Topic already exists"))
1258   (unless parent
1259     (setq parent (caar gnus-topic-topology)))
1260   (let ((top (cdr (gnus-topic-find-topology parent)))
1261         (full-topic (or full-topic (list (list topic 'visible nil nil)))))
1262     (unless top
1263       (error "No such parent topic: %s" parent))
1264     (if previous
1265         (progn
1266           (while (and (cdr top)
1267                       (not (equal (caaadr top) previous)))
1268             (setq top (cdr top)))
1269           (setcdr top (cons full-topic (cdr top))))
1270       (nconc top (list full-topic)))
1271     (unless (assoc topic gnus-topic-alist)
1272       (push (list topic) gnus-topic-alist)))
1273   (gnus-topic-enter-dribble)
1274   (gnus-group-list-groups)
1275   (gnus-topic-goto-topic topic))
1276
1277 ;; FIXME:
1278 ;;  1. When the marked groups are overlapped with the process
1279 ;;     region, the behavior of move or remove is not right.
1280 ;;  2. Can't process on several marked groups with a same name,
1281 ;;     because gnus-group-marked only keeps one copy.
1282
1283 (defvar gnus-topic-history nil)
1284
1285 (defun gnus-topic-move-group (n topic &optional copyp)
1286   "Move the next N groups to TOPIC.
1287 If COPYP, copy the groups instead."
1288   (interactive
1289    (list current-prefix-arg
1290          (gnus-completing-read "Move to topic" (mapcar 'car gnus-topic-alist) t
1291                                nil 'gnus-topic-history)))
1292   (let ((use-marked (and (not n) (not (and transient-mark-mode mark-active))
1293                          gnus-group-marked t))
1294         (groups (gnus-group-process-prefix n))
1295         (topicl (assoc topic gnus-topic-alist))
1296         (start-topic (gnus-group-topic-name))
1297         (start-group (progn (forward-line 1) (gnus-group-group-name)))
1298         entry)
1299     (if (and (not groups) (not copyp) start-topic)
1300         (gnus-topic-move start-topic topic)
1301       (dolist (g groups)
1302         (gnus-group-remove-mark g use-marked)
1303         (when (and
1304                (setq entry (assoc (gnus-current-topic) gnus-topic-alist))
1305                (not copyp))
1306           (setcdr entry (gnus-delete-first g (cdr entry))))
1307         (nconc topicl (list g)))
1308       (gnus-topic-enter-dribble)
1309       (if start-group
1310           (gnus-group-goto-group start-group)
1311         (gnus-topic-goto-topic start-topic))
1312       (gnus-group-list-groups))))
1313
1314 (defun gnus-topic-remove-group (&optional n)
1315   "Remove the current group from the topic."
1316   (interactive "P")
1317   (let ((use-marked (and (not n) (not (and transient-mark-mode mark-active))
1318                          gnus-group-marked t))
1319         (groups (gnus-group-process-prefix n)))
1320     (mapc
1321      (lambda (group)
1322        (gnus-group-remove-mark group use-marked)
1323        (let ((topicl (assoc (gnus-current-topic) gnus-topic-alist))
1324              (inhibit-read-only t))
1325          (when (and topicl group)
1326            (gnus-delete-line)
1327            (gnus-delete-first group topicl))
1328          (gnus-topic-update-topic)))
1329      groups)
1330     (gnus-topic-enter-dribble)
1331     (gnus-group-position-point)))
1332
1333 (defun gnus-topic-copy-group (n topic)
1334   "Copy the current group to a topic."
1335   (interactive
1336    (list current-prefix-arg
1337          (gnus-completing-read
1338           "Copy to topic" (mapcar 'car gnus-topic-alist) t)))
1339   (gnus-topic-move-group n topic t))
1340
1341 (defun gnus-topic-kill-group (&optional n discard)
1342   "Kill the next N groups."
1343   (interactive "P")
1344   (if (gnus-group-topic-p)
1345       (let ((topic (gnus-group-topic-name)))
1346         (push (cons
1347                (gnus-topic-find-topology topic)
1348                (assoc topic gnus-topic-alist))
1349               gnus-topic-killed-topics)
1350         (gnus-topic-remove-topic nil t)
1351         (gnus-topic-find-topology topic nil nil gnus-topic-topology)
1352         (gnus-topic-enter-dribble))
1353     (gnus-group-kill-group n discard)
1354     (if (not (gnus-group-topic-p))
1355         (gnus-topic-update-topic)
1356       ;; Move up one line so that we update the right topic.
1357       (forward-line -1)
1358       (gnus-topic-update-topic)
1359       (forward-line 1))))
1360
1361 (defun gnus-topic-yank-group (&optional arg)
1362   "Yank the last topic."
1363   (interactive "p")
1364   (if gnus-topic-killed-topics
1365       (let* ((previous
1366               (or (gnus-group-topic-name)
1367                   (gnus-topic-next-topic (gnus-current-topic))))
1368              (data (pop gnus-topic-killed-topics))
1369              (alist (cdr data))
1370              (item (cdar data)))
1371         (push alist gnus-topic-alist)
1372         (gnus-topic-create-topic
1373          (caar item) (gnus-topic-parent-topic previous) previous
1374          item)
1375         (gnus-topic-enter-dribble)
1376         (gnus-topic-goto-topic (caar item)))
1377     (let* ((prev (gnus-group-group-name))
1378            (gnus-topic-inhibit-change-level t)
1379            (gnus-group-indentation
1380             (make-string
1381              (* gnus-topic-indent-level
1382                 (or (save-excursion
1383                       (gnus-topic-goto-topic (gnus-current-topic))
1384                       (gnus-group-topic-level))
1385                     0))
1386              ? ))
1387            yanked alist)
1388       ;; We first yank the groups the normal way...
1389       (setq yanked (gnus-group-yank-group arg))
1390       ;; Then we enter the yanked groups into the topics they belong
1391       ;; to.
1392       (setq alist (assoc (save-excursion
1393                            (forward-line -1)
1394                            (gnus-current-topic))
1395                          gnus-topic-alist))
1396       (when (stringp yanked)
1397         (setq yanked (list yanked)))
1398       (if (not prev)
1399           (nconc alist yanked)
1400         (if (not (cdr alist))
1401             (setcdr alist (nconc yanked (cdr alist)))
1402           (while (cdr alist)
1403             (when (equal (cadr alist) prev)
1404               (setcdr alist (nconc yanked (cdr alist)))
1405               (setq alist nil))
1406             (setq alist (cdr alist))))))
1407     (gnus-topic-update-topic)))
1408
1409 (defun gnus-topic-hide-topic (&optional permanent)
1410   "Hide the current topic.
1411 If PERMANENT, make it stay hidden in subsequent sessions as well."
1412   (interactive "P")
1413   (when (gnus-current-topic)
1414     (gnus-topic-goto-topic (gnus-current-topic))
1415     (if permanent
1416         (setcar (cddr
1417                  (cadr
1418                   (gnus-topic-find-topology (gnus-current-topic))))
1419                 'hidden))
1420     (gnus-topic-remove-topic nil nil)))
1421
1422 (defun gnus-topic-show-topic (&optional permanent)
1423   "Show the hidden topic.
1424 If PERMANENT, make it stay shown in subsequent sessions as well."
1425   (interactive "P")
1426   (when (gnus-group-topic-p)
1427     (if (not permanent)
1428         (gnus-topic-remove-topic t nil)
1429       (let ((topic
1430              (gnus-topic-find-topology
1431               (gnus-completing-read "Show topic"
1432                                     (mapcar 'car gnus-topic-alist) t))))
1433         (setcar (cddr (cadr topic)) nil)
1434         (setcar (cdr (cadr topic)) 'visible)
1435         (gnus-group-list-groups)))))
1436
1437 (defun gnus-topic-mark-topic (topic &optional unmark non-recursive)
1438   "Mark all groups in the TOPIC with the process mark.
1439 If NON-RECURSIVE (which is the prefix) is t, don't mark its subtopics."
1440   (interactive (list (gnus-group-topic-name)
1441                      nil
1442                      (and current-prefix-arg t)))
1443   (if (not topic)
1444       (call-interactively 'gnus-group-mark-group)
1445     (save-excursion
1446       (let ((groups (gnus-topic-find-groups topic gnus-level-killed t nil
1447                                             (not non-recursive))))
1448         (while groups
1449           (funcall (if unmark 'gnus-group-remove-mark 'gnus-group-set-mark)
1450                    (gnus-info-group (nth 2 (pop groups)))))))))
1451
1452 (defun gnus-topic-unmark-topic (topic &optional _dummy non-recursive)
1453   "Remove the process mark from all groups in the TOPIC.
1454 If NON-RECURSIVE (which is the prefix) is t, don't unmark 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-unmark-group)
1460     (gnus-topic-mark-topic topic t non-recursive)))
1461
1462 (defun gnus-topic-get-new-news-this-topic (&optional n)
1463   "Check for new news in the current topic."
1464   (interactive "P")
1465   (if (not (gnus-group-topic-p))
1466       (gnus-group-get-new-news-this-group n)
1467     (let* ((topic (gnus-group-topic-name))
1468            (data (cadr (gnus-topic-find-topology topic))))
1469       (save-excursion
1470         (gnus-topic-mark-topic topic nil (and n t))
1471         (gnus-group-get-new-news-this-group))
1472       (gnus-topic-remove-topic (eq 'visible (cadr data))))))
1473
1474 (defun gnus-topic-move-matching (regexp topic &optional copyp)
1475   "Move all groups that match REGEXP to some topic."
1476   (interactive
1477    (let (topic)
1478      (nreverse
1479       (list
1480        (setq topic (gnus-completing-read "Move to topic"
1481                                          (mapcar 'car gnus-topic-alist) t))
1482        (read-string (format "Move to %s (regexp): " topic))))))
1483   (gnus-group-mark-regexp regexp)
1484   (gnus-topic-move-group nil topic copyp))
1485
1486 (defun gnus-topic-copy-matching (regexp topic &optional _copyp)
1487   "Copy all groups that match REGEXP to some topic."
1488   (interactive
1489    (let ((topic (gnus-completing-read "Copy to topic"
1490                                       (mapcar #'car gnus-topic-alist) t)))
1491      (nreverse
1492       (list topic
1493             (read-string (format "Copy to %s (regexp): " topic))))))
1494   (gnus-topic-move-matching regexp topic t))
1495
1496 (defun gnus-topic-delete (topic)
1497   "Delete a topic."
1498   (interactive (list (gnus-group-topic-name)))
1499   (unless topic
1500     (error "No topic to be deleted"))
1501   (let ((entry (assoc topic gnus-topic-alist))
1502         (inhibit-read-only t))
1503     (when (cdr entry)
1504       (error "Topic not empty"))
1505     ;; Delete if visible.
1506     (when (gnus-topic-goto-topic topic)
1507       (gnus-delete-line))
1508     ;; Remove from alist.
1509     (setq gnus-topic-alist (delq entry gnus-topic-alist))
1510     ;; Remove from topology.
1511     (gnus-topic-find-topology topic nil nil 'delete)
1512     (gnus-dribble-touch)))
1513
1514 (defun gnus-topic-rename (old-name new-name)
1515   "Rename a topic."
1516   (interactive
1517    (let ((topic (gnus-current-topic)))
1518      (list topic
1519            (read-string (format "Rename %s to: " topic) topic))))
1520   ;; Check whether the new name exists.
1521   (when (gnus-topic-find-topology new-name)
1522     (error "Topic `%s' already exists" new-name))
1523   ;; "nil" is an invalid name, for reasons I'd rather not go
1524   ;; into here.  Trust me.
1525   (when (equal new-name "nil")
1526     (error "Invalid name: %s" nil))
1527   ;; Do the renaming.
1528   (let ((top (gnus-topic-find-topology old-name))
1529         (entry (assoc old-name gnus-topic-alist)))
1530     (when top
1531       (setcar (cadr top) new-name))
1532     (when entry
1533       (setcar entry new-name))
1534     (forward-line -1)
1535     (gnus-dribble-touch)
1536     (gnus-group-list-groups)
1537     (forward-line 1)))
1538
1539 (defun gnus-topic-indent (&optional unindent)
1540   "Indent a topic -- make it a sub-topic of the previous topic.
1541 If UNINDENT, remove an indentation."
1542   (interactive "P")
1543   (if unindent
1544       (gnus-topic-unindent)
1545     (let* ((topic (gnus-current-topic))
1546            (parent (gnus-topic-previous-topic topic))
1547            (inhibit-read-only t))
1548       (unless parent
1549         (error "Nothing to indent %s into" topic))
1550       (when topic
1551         (gnus-topic-goto-topic topic)
1552         (gnus-topic-kill-group)
1553         (push (cdar gnus-topic-killed-topics) gnus-topic-alist)
1554         (gnus-topic-create-topic
1555          topic parent nil (cdar (car gnus-topic-killed-topics)))
1556         (pop gnus-topic-killed-topics)
1557         (or (gnus-topic-goto-topic topic)
1558             (gnus-topic-goto-topic parent))))))
1559
1560 (defun gnus-topic-unindent ()
1561   "Unindent a topic."
1562   (interactive)
1563   (let* ((topic (gnus-current-topic))
1564          (parent (gnus-topic-parent-topic topic))
1565          (grandparent (gnus-topic-parent-topic parent)))
1566     (unless grandparent
1567       (error "Can't unindent %s further" topic))
1568     (when topic
1569       (gnus-topic-goto-topic topic)
1570       (gnus-topic-kill-group)
1571       (push (cdar gnus-topic-killed-topics) gnus-topic-alist)
1572       (gnus-topic-create-topic
1573        topic grandparent (gnus-topic-next-topic parent)
1574        (cdar (car gnus-topic-killed-topics)))
1575       (pop gnus-topic-killed-topics)
1576       (gnus-topic-goto-topic topic))))
1577
1578 (defun gnus-topic-list-active (&optional force)
1579   "List all groups that Gnus knows about in a topicsified fashion.
1580 If FORCE, always re-read the active file."
1581   (interactive "P")
1582   (when force
1583     (gnus-get-killed-groups))
1584   (gnus-topic-grok-active force)
1585   (let ((gnus-topic-topology gnus-topic-active-topology)
1586         (gnus-topic-alist gnus-topic-active-alist)
1587         gnus-killed-list gnus-zombie-list)
1588     (gnus-group-list-groups gnus-level-killed nil 1)))
1589
1590 (defun gnus-topic-toggle-display-empty-topics ()
1591   "Show/hide topics that have no unread articles."
1592   (interactive)
1593   (setq gnus-topic-display-empty-topics
1594         (not gnus-topic-display-empty-topics))
1595   (gnus-group-list-groups)
1596   (message "%s empty topics"
1597            (if gnus-topic-display-empty-topics
1598                "Showing" "Hiding")))
1599
1600 ;;; Topic sorting functions
1601
1602 (defun gnus-topic-edit-parameters (group)
1603   "Edit the group parameters of GROUP.
1604 If performed on a topic, edit the topic parameters instead."
1605   (interactive (list (gnus-group-group-name)))
1606   (if group
1607       (gnus-group-edit-group-parameters group)
1608     (if (not (gnus-group-topic-p))
1609         (error "Nothing to edit on the current line")
1610       (let ((topic (gnus-group-topic-name)))
1611         (gnus-edit-form
1612          (gnus-topic-parameters topic)
1613          (format-message "Editing the topic parameters for `%s'."
1614                          (or group topic))
1615          `(lambda (form)
1616             (gnus-topic-set-parameters ,topic form)))))))
1617
1618 (defun gnus-group-sort-topic (func reverse)
1619   "Sort groups in the topics according to FUNC and REVERSE."
1620   (let ((alist gnus-topic-alist))
1621     (while alist
1622       ;; !!!Sometimes nil elements sneak into the alist,
1623       ;; for some reason or other.
1624       (setcar alist (delq nil (car alist)))
1625       (setcar alist (delete "dummy.group" (car alist)))
1626       (gnus-topic-sort-topic (pop alist) func reverse))))
1627
1628 (defun gnus-topic-sort-topic (topic func reverse)
1629   ;; Each topic only lists the name of the group, while
1630   ;; the sort predicates expect group infos as inputs.
1631   ;; So we first transform the group names into infos,
1632   ;; then sort, and then transform back into group names.
1633   (setcdr
1634    topic
1635    (mapcar
1636     (lambda (info) (gnus-info-group info))
1637     (sort
1638      (mapcar
1639       (lambda (group) (gnus-get-info group))
1640       (cdr topic))
1641      func)))
1642   ;; Do the reversal, if necessary.
1643   (when reverse
1644     (setcdr topic (nreverse (cdr topic)))))
1645
1646 (defun gnus-topic-sort-groups (func &optional reverse)
1647   "Sort the current topic according to FUNC.
1648 If REVERSE, reverse the sorting order."
1649   (interactive (list gnus-group-sort-function current-prefix-arg))
1650   (let ((topic (assoc (gnus-current-topic) gnus-topic-alist)))
1651     (gnus-topic-sort-topic
1652      topic (gnus-make-sort-function func) reverse)
1653     (gnus-group-list-groups)))
1654
1655 (defun gnus-topic-sort-groups-by-alphabet (&optional reverse)
1656   "Sort the current topic alphabetically by group name.
1657 If REVERSE, sort in reverse order."
1658   (interactive "P")
1659   (gnus-topic-sort-groups 'gnus-group-sort-by-alphabet reverse))
1660
1661 (defun gnus-topic-sort-groups-by-unread (&optional reverse)
1662   "Sort the current topic by number of unread articles.
1663 If REVERSE, sort in reverse order."
1664   (interactive "P")
1665   (gnus-topic-sort-groups 'gnus-group-sort-by-unread reverse))
1666
1667 (defun gnus-topic-sort-groups-by-level (&optional reverse)
1668   "Sort the current topic by group level.
1669 If REVERSE, sort in reverse order."
1670   (interactive "P")
1671   (gnus-topic-sort-groups 'gnus-group-sort-by-level reverse))
1672
1673 (defun gnus-topic-sort-groups-by-score (&optional reverse)
1674   "Sort the current topic by group score.
1675 If REVERSE, sort in reverse order."
1676   (interactive "P")
1677   (gnus-topic-sort-groups 'gnus-group-sort-by-score reverse))
1678
1679 (defun gnus-topic-sort-groups-by-rank (&optional reverse)
1680   "Sort the current topic by group rank.
1681 If REVERSE, sort in reverse order."
1682   (interactive "P")
1683   (gnus-topic-sort-groups 'gnus-group-sort-by-rank reverse))
1684
1685 (defun gnus-topic-sort-groups-by-method (&optional reverse)
1686   "Sort the current topic alphabetically by backend name.
1687 If REVERSE, sort in reverse order."
1688   (interactive "P")
1689   (gnus-topic-sort-groups 'gnus-group-sort-by-method reverse))
1690
1691 (defun gnus-topic-sort-groups-by-server (&optional reverse)
1692   "Sort the current topic alphabetically by server name.
1693 If REVERSE, sort in reverse order."
1694   (interactive "P")
1695   (gnus-topic-sort-groups 'gnus-group-sort-by-server reverse))
1696
1697 (defun gnus-topic-sort-topics-1 (top reverse)
1698   (if (cdr top)
1699       (let ((subtop
1700              (mapcar (gnus-byte-compile
1701                       `(lambda (top)
1702                          (gnus-topic-sort-topics-1 top ,reverse)))
1703                      (sort (cdr top)
1704                            (lambda (t1 t2)
1705                              (string-lessp (caar t1) (caar t2)))))))
1706         (setcdr top (if reverse (reverse subtop) subtop))))
1707   top)
1708
1709 (defun gnus-topic-sort-topics (&optional topic reverse)
1710   "Sort topics in TOPIC alphabetically by topic name.
1711 If REVERSE, reverse the sorting order."
1712   (interactive
1713    (list (gnus-completing-read "Sort topics in"
1714                                (mapcar 'car gnus-topic-alist) t
1715                                (gnus-current-topic))
1716          current-prefix-arg))
1717   (let ((topic-topology (or (and topic (cdr (gnus-topic-find-topology topic)))
1718                             gnus-topic-topology)))
1719     (gnus-topic-sort-topics-1 topic-topology reverse)
1720     (gnus-topic-enter-dribble)
1721     (gnus-group-list-groups)
1722     (gnus-topic-goto-topic topic)))
1723
1724 (defun gnus-topic-move (current to)
1725   "Move the CURRENT topic to TO."
1726   (interactive
1727    (list
1728     (gnus-group-topic-name)
1729     (gnus-completing-read "Move to topic" (mapcar 'car gnus-topic-alist) t)))
1730   (unless (and current to)
1731     (error "Can't find topic"))
1732   (let ((current-top (cdr (gnus-topic-find-topology current)))
1733         (to-top (cdr (gnus-topic-find-topology to))))
1734     (unless current-top
1735       (error "Can't find topic `%s'" current))
1736     (unless to-top
1737       (error "Can't find topic `%s'" to))
1738     (if (gnus-topic-find-topology to current-top 0);; Don't care the level
1739         (error "Can't move `%s' to its sub-level" current))
1740     (gnus-topic-find-topology current nil nil 'delete)
1741     (setcdr (last to-top) (list current-top))
1742     (gnus-topic-enter-dribble)
1743     (gnus-group-list-groups)
1744     (gnus-topic-goto-topic current)))
1745
1746 (defun gnus-subscribe-topics (newsgroup)
1747   (catch 'end
1748     (let (match gnus-group-change-level-function)
1749       (dolist (topic (gnus-topic-list))
1750         (when (and (setq match (cdr (assq 'subscribe
1751                                           (gnus-topic-parameters topic))))
1752                    (string-match match newsgroup))
1753           ;; Just subscribe the group.
1754           (gnus-subscribe-alphabetically newsgroup)
1755           ;; Add the group to the topic.
1756           (nconc (assoc topic gnus-topic-alist) (list newsgroup))
1757           ;; if this topic specifies a default level, use it
1758           (let ((subscribe-level (cdr (assq 'subscribe-level
1759                                             (gnus-topic-parameters topic)))))
1760             (when subscribe-level
1761                 (gnus-group-change-level newsgroup subscribe-level
1762                                          gnus-level-default-subscribed)))
1763           (throw 'end t)))
1764       nil)))
1765
1766 (provide 'gnus-topic)
1767
1768 ;;; gnus-topic.el ends here