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[gnus] / lisp / gnus-group.el

;;; gnus-group.el --- group mode commands for Gnus
;; Copyright (C) 1996 Free Software Foundation, Inc.

;; Author: Lars Magne Ingebrigtsen <larsi@ifi.uio.no>
;; Keywords: news

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;;; Code:

(require 'gnus-load)
(require 'gnus-start)
(require 'nnmail)
(require 'gnus-spec)
(require 'gnus-int)
(require 'gnus-range)
(require 'gnus-win)
(require 'gnus-undo)

(defvar gnus-group-archive-directory
  "/ftp@ftp.hpc.uh.edu:/pub/emacs/ding-list/"
  "*The address of the (ding) archives.")

(defvar gnus-group-recent-archive-directory
  "/ftp@ftp.hpc.uh.edu:/pub/emacs/ding-list-recent/"
  "*The address of the most recent (ding) articles.")

;; Suggested by Andrew Eskilsson <pi92ae@lelle.pt.hk-r.se>.
(defvar gnus-no-groups-message "No news is horrible news"
  "*Message displayed by Gnus when no groups are available.")

(defvar gnus-keep-same-level nil
  "*Non-nil means that the next newsgroup after the current will be on the same level.
When you type, for instance, `n' after reading the last article in the
current newsgroup, you will go to the next newsgroup.  If this variable
is nil, the next newsgroup will be the next from the group
buffer.
If this variable is non-nil, Gnus will either put you in the
next newsgroup with the same level, or, if no such newsgroup is
available, the next newsgroup with the lowest possible level higher
than the current level.
If this variable is `best', Gnus will make the next newsgroup the one
with the best level.")

(defvar gnus-group-goto-unread t
  "*If non-nil, movement commands will go to the next unread and subscribed group.")

(defvar gnus-goto-next-group-when-activating t
  "*If non-nil, the \\<gnus-group-mode-map>\\[gnus-group-get-new-news-this-group] command will advance point to the next group.")

(defvar gnus-permanently-visible-groups nil
  "*Regexp to match groups that should always be listed in the group buffer.
This means that they will still be listed when there are no unread
articles in the groups.")

(defvar gnus-list-groups-with-ticked-articles t
  "*If non-nil, list groups that have only ticked articles.
If nil, only list groups that have unread articles.")

(defvar gnus-group-default-list-level gnus-level-subscribed
  "*Default listing level.
Ignored if `gnus-group-use-permanent-levels' is non-nil.")

(defvar gnus-group-list-inactive-groups t
  "*If non-nil, inactive groups will be listed.")

(defvar gnus-group-sort-function 'gnus-group-sort-by-alphabet
  "*Function used for sorting the group buffer.
This function will be called with group info entries as the arguments
for the groups to be sorted.  Pre-made functions include
`gnus-group-sort-by-alphabet', `gnus-group-sort-by-unread',
`gnus-group-sort-by-level', `gnus-group-sort-by-score',
`gnus-group-sort-by-method', and `gnus-group-sort-by-rank'.

This variable can also be a list of sorting functions.  In that case,
the most significant sort function should be the last function in the
list.")

(defvar gnus-group-line-format "%M\%S\%p\%P\%5y: %(%g%)%l\n"
  "*Format of group lines.
It works along the same lines as a normal formatting string,
with some simple extensions.

%M    Only marked articles (character, \"*\" or \" \")
%S    Whether the group is subscribed (character, \"U\", \"K\", \"Z\" or \" \")
%L    Level of subscribedness (integer)
%N    Number of unread articles (integer)
%I    Number of dormant articles (integer)
%i    Number of ticked and dormant (integer)
%T    Number of ticked articles (integer)
%R    Number of read articles (integer)
%t    Estimated total number of articles (integer)
%y    Number of unread, unticked articles (integer)
%G    Group name (string)
%g    Qualified group name (string)
%D    Group description (string)
%s    Select method (string)
%o    Moderated group (char, \"m\")
%p    Process mark (char)
%O    Moderated group (string, \"(m)\" or \"\")
%P    Topic indentation (string)
%l    Whether there are GroupLens predictions for this group (string)
%n    Select from where (string)
%z    A string that look like `<%s:%n>' if a foreign select method is used
%u    User defined specifier.  The next character in the format string should
      be a letter.  Gnus will call the function gnus-user-format-function-X,
      where X is the letter following %u.  The function will be passed the
      current header as argument.  The function should return a string, which
      will be inserted into the buffer just like information from any other
      group specifier.

Text between %( and %) will be highlighted with `gnus-mouse-face' when
the mouse point move inside the area.  There can only be one such area.

Note that this format specification is not always respected.  For
reasons of efficiency, when listing killed groups, this specification
is ignored altogether.  If the spec is changed considerably, your
output may end up looking strange when listing both alive and killed
groups.

If you use %o or %O, reading the active file will be slower and quite
a bit of extra memory will be used. %D will also worsen performance.
Also note that if you change the format specification to include any
of these specs, you must probably re-start Gnus to see them go into
effect.")

(defvar gnus-group-mode-line-format "Gnus: %%b {%M\%:%S}"
  "*The format specification for the group mode line.
It works along the same lines as a normal formatting string,
with some simple extensions:

%S   The native news server.
%M   The native select method.
%:   \":\" if %S isn't \"\".")

(defvar gnus-group-mode-hook nil
  "*A hook for Gnus group mode.")

(defvar gnus-group-menu-hook nil
  "*Hook run after the creation of the group mode menu.")

(defvar gnus-group-catchup-group-hook nil
  "*A hook run when catching up a group from the group buffer.")

(defvar gnus-group-update-group-hook nil
  "*A hook called when updating group lines.")

(defvar gnus-group-prepare-function 'gnus-group-prepare-flat
  "*A function that is called to generate the group buffer.
The function is called with three arguments: The first is a number;
all group with a level less or equal to that number should be listed,
if the second is non-nil, empty groups should also be displayed.  If
the third is non-nil, it is a number.  No groups with a level lower
than this number should be displayed.

The only current function implemented is `gnus-group-prepare-flat'.")

(defvar gnus-group-prepare-hook nil
  "*A hook called after the group buffer has been generated.
If you want to modify the group buffer, you can use this hook.")

(defvar gnus-suspend-gnus-hook nil
  "*A hook called when suspending (not exiting) Gnus.")

(defvar gnus-exit-gnus-hook nil
  "*A hook called when exiting Gnus.")

(defvar gnus-after-exiting-gnus-hook nil
  "*A hook called after exiting Gnus.")

(defvar gnus-group-update-hook '(gnus-group-highlight-line)
  "*A hook called when a group line is changed.
The hook will not be called if `gnus-visual' is nil.

The default function `gnus-group-highlight-line' will
highlight the line according to the `gnus-group-highlight'
variable.")

;;; Internal variables

(defvar gnus-group-indentation-function nil)
(defvar gnus-goto-missing-group-function nil)
(defvar gnus-group-get-parameter-function 'gnus-group-get-parameter)
(defvar gnus-group-goto-next-group-function nil
  "Function to override finding the next group after listing groups.")

(defvar gnus-group-edit-buffer nil)

(defvar gnus-group-line-format-alist
  `((?M gnus-tmp-marked-mark ?c)
    (?S gnus-tmp-subscribed ?c)
    (?L gnus-tmp-level ?d)
    (?N (cond ((eq number t) "*" )
              ((numberp number) 
               (int-to-string
                (+ number
                   (gnus-range-length (cdr (assq 'dormant gnus-tmp-marked)))
                   (gnus-range-length (cdr (assq 'tick gnus-tmp-marked))))))
              (t number)) ?s)
    (?R gnus-tmp-number-of-read ?s)
    (?t gnus-tmp-number-total ?d)
    (?y gnus-tmp-number-of-unread ?s)
    (?I (gnus-range-length (cdr (assq 'dormant gnus-tmp-marked))) ?d)
    (?T (gnus-range-length (cdr (assq 'tick gnus-tmp-marked))) ?d)
    (?i (+ (gnus-range-length (cdr (assq 'dormant gnus-tmp-marked)))
           (gnus-range-length (cdr (assq 'tick gnus-tmp-marked)))) ?d)
    (?g gnus-tmp-group ?s)
    (?G gnus-tmp-qualified-group ?s)
    (?c (gnus-short-group-name gnus-tmp-group) ?s)
    (?D gnus-tmp-newsgroup-description ?s)
    (?o gnus-tmp-moderated ?c)
    (?O gnus-tmp-moderated-string ?s)
    (?p gnus-tmp-process-marked ?c)
    (?s gnus-tmp-news-server ?s)
    (?n gnus-tmp-news-method ?s)
    (?P gnus-group-indentation ?s)
    (?l gnus-tmp-grouplens ?s)
    (?z gnus-tmp-news-method-string ?s)
    (?u gnus-tmp-user-defined ?s)))

(defvar gnus-group-mode-line-format-alist
  `((?S gnus-tmp-news-server ?s)
    (?M gnus-tmp-news-method ?s)
    (?u gnus-tmp-user-defined ?s)
    (?: gnus-tmp-colon ?s)))

(defvar gnus-topic-topology nil
  "The complete topic hierarchy.")

(defvar gnus-topic-alist nil
  "The complete topic-group alist.")

(defvar gnus-group-marked nil)

(defvar gnus-group-list-mode nil)

;;;
;;; Gnus group mode
;;;

(put 'gnus-group-mode 'mode-class 'special)

(when t
  (gnus-define-keys gnus-group-mode-map
    " " gnus-group-read-group
    "=" gnus-group-select-group
    "\r" gnus-group-select-group
    "\M-\r" gnus-group-quick-select-group
    "j" gnus-group-jump-to-group
    "n" gnus-group-next-unread-group
    "p" gnus-group-prev-unread-group
    "\177" gnus-group-prev-unread-group
    [delete] gnus-group-prev-unread-group
    "N" gnus-group-next-group
    "P" gnus-group-prev-group
    "\M-n" gnus-group-next-unread-group-same-level
    "\M-p" gnus-group-prev-unread-group-same-level
    "," gnus-group-best-unread-group
    "." gnus-group-first-unread-group
    "u" gnus-group-unsubscribe-current-group
    "U" gnus-group-unsubscribe-group
    "c" gnus-group-catchup-current
    "C" gnus-group-catchup-current-all
    "\M-c" gnus-group-clear-data
    "l" gnus-group-list-groups
    "L" gnus-group-list-all-groups
    "m" gnus-group-mail
    "g" gnus-group-get-new-news
    "\M-g" gnus-group-get-new-news-this-group
    "R" gnus-group-restart
    "r" gnus-group-read-init-file
    "B" gnus-group-browse-foreign-server
    "b" gnus-group-check-bogus-groups
    "F" gnus-find-new-newsgroups
    "\C-c\C-d" gnus-group-describe-group
    "\M-d" gnus-group-describe-all-groups
    "\C-c\C-a" gnus-group-apropos
    "\C-c\M-\C-a" gnus-group-description-apropos
    "a" gnus-group-post-news
    "\ek" gnus-group-edit-local-kill
    "\eK" gnus-group-edit-global-kill
    "\C-k" gnus-group-kill-group
    "\C-y" gnus-group-yank-group
    "\C-w" gnus-group-kill-region
    "\C-x\C-t" gnus-group-transpose-groups
    "\C-c\C-l" gnus-group-list-killed
    "\C-c\C-x" gnus-group-expire-articles
    "\C-c\M-\C-x" gnus-group-expire-all-groups
    "V" gnus-version
    "s" gnus-group-save-newsrc
    "z" gnus-group-suspend
                                        ;    "Z" gnus-group-clear-dribble
    "q" gnus-group-exit
    "Q" gnus-group-quit
    "?" gnus-group-describe-briefly
    "\C-c\C-i" gnus-info-find-node
    "\M-e" gnus-group-edit-group-method
    "^" gnus-group-enter-server-mode
    gnus-mouse-2 gnus-mouse-pick-group
    "<" beginning-of-buffer
    ">" end-of-buffer
    "\C-c\C-b" gnus-bug
    "\C-c\C-s" gnus-group-sort-groups
    "t" gnus-topic-mode
    "\C-c\M-g" gnus-activate-all-groups
    "\M-&" gnus-group-universal-argument
    "#" gnus-group-mark-group
    "\M-#" gnus-group-unmark-group)

  (gnus-define-keys (gnus-group-mark-map "M" gnus-group-mode-map)
    "m" gnus-group-mark-group
    "u" gnus-group-unmark-group
    "w" gnus-group-mark-region
    "m" gnus-group-mark-buffer
    "r" gnus-group-mark-regexp
    "U" gnus-group-unmark-all-groups)

  (gnus-define-keys (gnus-group-group-map "G" gnus-group-mode-map)
    "d" gnus-group-make-directory-group
    "h" gnus-group-make-help-group
    "a" gnus-group-make-archive-group
    "k" gnus-group-make-kiboze-group
    "m" gnus-group-make-group
    "E" gnus-group-edit-group
    "e" gnus-group-edit-group-method
    "p" gnus-group-edit-group-parameters
    "v" gnus-group-add-to-virtual
    "V" gnus-group-make-empty-virtual
    "D" gnus-group-enter-directory
    "f" gnus-group-make-doc-group
    "r" gnus-group-rename-group
    "\177" gnus-group-delete-group
    [delete] gnus-group-delete-group)

  (gnus-define-keys (gnus-group-soup-map "s" gnus-group-group-map)
    "b" gnus-group-brew-soup
    "w" gnus-soup-save-areas
    "s" gnus-soup-send-replies
    "p" gnus-soup-pack-packet
    "r" nnsoup-pack-replies)

  (gnus-define-keys (gnus-group-sort-map "S" gnus-group-group-map)
    "s" gnus-group-sort-groups
    "a" gnus-group-sort-groups-by-alphabet
    "u" gnus-group-sort-groups-by-unread
    "l" gnus-group-sort-groups-by-level
    "v" gnus-group-sort-groups-by-score
    "r" gnus-group-sort-groups-by-rank
    "m" gnus-group-sort-groups-by-method)

  (gnus-define-keys (gnus-group-list-map "A" gnus-group-mode-map)
    "k" gnus-group-list-killed
    "z" gnus-group-list-zombies
    "s" gnus-group-list-groups
    "u" gnus-group-list-all-groups
    "A" gnus-group-list-active
    "a" gnus-group-apropos
    "d" gnus-group-description-apropos
    "m" gnus-group-list-matching
    "M" gnus-group-list-all-matching
    "l" gnus-group-list-level)

  (gnus-define-keys (gnus-group-score-map "W" gnus-group-mode-map)
    "f" gnus-score-flush-cache)

  (gnus-define-keys (gnus-group-help-map "H" gnus-group-mode-map)
    "f" gnus-group-fetch-faq)

  (gnus-define-keys (gnus-group-sub-map "S" gnus-group-mode-map)
    "l" gnus-group-set-current-level
    "t" gnus-group-unsubscribe-current-group
    "s" gnus-group-unsubscribe-group
    "k" gnus-group-kill-group
    "y" gnus-group-yank-group
    "w" gnus-group-kill-region
    "\C-k" gnus-group-kill-level
    "z" gnus-group-kill-all-zombies))


(defun gnus-group-make-menu-bar ()
  (gnus-turn-off-edit-menu 'group)
  (unless (boundp 'gnus-group-reading-menu)

    (easy-menu-define
     gnus-group-reading-menu gnus-group-mode-map ""
     '("Group"
       ["Read" gnus-group-read-group (gnus-group-group-name)]
       ["Select" gnus-group-select-group (gnus-group-group-name)]
       ["See old articles" (gnus-group-select-group 'all)
        :keys "C-u SPC" :active (gnus-group-group-name)]
       ["Catch up" gnus-group-catchup-current (gnus-group-group-name)]
       ["Catch up all articles" gnus-group-catchup-current-all
        (gnus-group-group-name)]
       ["Check for new articles" gnus-group-get-new-news-this-group
        (gnus-group-group-name)]
       ["Toggle subscription" gnus-group-unsubscribe-current-group
        (gnus-group-group-name)]
       ["Kill" gnus-group-kill-group (gnus-group-group-name)]
       ["Yank" gnus-group-yank-group gnus-list-of-killed-groups]
       ["Describe" gnus-group-describe-group (gnus-group-group-name)]
       ["Fetch FAQ" gnus-group-fetch-faq (gnus-group-group-name)]
       ["Edit kill file" gnus-group-edit-local-kill
        (gnus-group-group-name)]
       ;; Actually one should check, if any of the marked groups gives t for
       ;; (gnus-check-backend-function 'request-expire-articles ...)
       ["Expire articles" gnus-group-expire-articles
        (or (and (gnus-group-group-name)
                 (gnus-check-backend-function
                  'request-expire-articles
                  (gnus-group-group-name))) gnus-group-marked)]
       ["Set group level" gnus-group-set-current-level
        (gnus-group-group-name)]
       ["Select quick" gnus-group-quick-select-group (gnus-group-group-name)]
       ))
  
    (easy-menu-define
     gnus-group-group-menu gnus-group-mode-map ""
     '("Groups"
       ("Listing"
        ["List unread subscribed groups" gnus-group-list-groups t]
        ["List (un)subscribed groups" gnus-group-list-all-groups t]
        ["List killed groups" gnus-group-list-killed gnus-killed-list]
        ["List zombie groups" gnus-group-list-zombies gnus-zombie-list]
        ["List level..." gnus-group-list-level t]
        ["Describe all groups" gnus-group-describe-all-groups t]
        ["Group apropos..." gnus-group-apropos t]
        ["Group and description apropos..." gnus-group-description-apropos t]
        ["List groups matching..." gnus-group-list-matching t]
        ["List all groups matching..." gnus-group-list-all-matching t]
        ["List active file" gnus-group-list-active t])
       ("Sort"
        ["Default sort" gnus-group-sort-groups
         (or (not (boundp 'gnus-topic-mode)) (not gnus-topic-mode))]
        ["Sort by method" gnus-group-sort-groups-by-method
         (or (not (boundp 'gnus-topic-mode)) (not gnus-topic-mode))]
        ["Sort by rank" gnus-group-sort-groups-by-rank
         (or (not (boundp 'gnus-topic-mode)) (not gnus-topic-mode))]
        ["Sort by score" gnus-group-sort-groups-by-score
         (or (not (boundp 'gnus-topic-mode)) (not gnus-topic-mode))]
        ["Sort by level" gnus-group-sort-groups-by-level
         (or (not (boundp 'gnus-topic-mode)) (not gnus-topic-mode))]
        ["Sort by unread" gnus-group-sort-groups-by-unread
         (or (not (boundp 'gnus-topic-mode)) (not gnus-topic-mode))]
        ["Sort by name" gnus-group-sort-groups-by-alphabet
         (or (not (boundp 'gnus-topic-mode)) (not gnus-topic-mode))])
       ("Mark"
        ["Mark group" gnus-group-mark-group
         (and (gnus-group-group-name)
              (not (memq (gnus-group-group-name) gnus-group-marked)))]
        ["Unmark group" gnus-group-unmark-group
         (and (gnus-group-group-name)
              (memq (gnus-group-group-name) gnus-group-marked))]
        ["Unmark all" gnus-group-unmark-all-groups gnus-group-marked]
        ["Mark regexp..." gnus-group-mark-regexp t]
        ["Mark region" gnus-group-mark-region t]
        ["Mark buffer" gnus-group-mark-buffer t]
        ["Execute command" gnus-group-universal-argument
         (or gnus-group-marked (gnus-group-group-name))])
       ("Subscribe"
        ["Subscribe to a group" gnus-group-unsubscribe-group t]
        ["Kill all newsgroups in region" gnus-group-kill-region t]
        ["Kill all zombie groups" gnus-group-kill-all-zombies
         gnus-zombie-list]
        ["Kill all groups on level..." gnus-group-kill-level t])
       ("Foreign groups"
        ["Make a foreign group" gnus-group-make-group t]
        ["Add a directory group" gnus-group-make-directory-group t]
        ["Add the help group" gnus-group-make-help-group t]
        ["Add the archive group" gnus-group-make-archive-group t]
        ["Make a doc group" gnus-group-make-doc-group t]
        ["Make a kiboze group" gnus-group-make-kiboze-group t]
        ["Make a virtual group" gnus-group-make-empty-virtual t]
        ["Add a group to a virtual" gnus-group-add-to-virtual t]
        ["Rename group" gnus-group-rename-group
         (gnus-check-backend-function
          'request-rename-group (gnus-group-group-name))]
        ["Delete group" gnus-group-delete-group
         (gnus-check-backend-function
          'request-delete-group (gnus-group-group-name))])
       ("Editing groups"
        ["Parameters" gnus-group-edit-group-parameters
         (gnus-group-group-name)]
        ["Select method" gnus-group-edit-group-method
         (gnus-group-group-name)]
        ["Info" gnus-group-edit-group (gnus-group-group-name)])
       ("Score file"
        ["Flush cache" gnus-score-flush-cache
         (or gnus-score-cache gnus-short-name-score-file-cache)])
       ("Move"
        ["Next" gnus-group-next-group t]
        ["Previous" gnus-group-prev-group t]
        ["Next unread" gnus-group-next-unread-group t]
        ["Previous unread" gnus-group-prev-unread-group t]
        ["Next unread same level" gnus-group-next-unread-group-same-level t]
        ["Previous unread same level"
         gnus-group-previous-unread-group-same-level t]
        ["Jump to group" gnus-group-jump-to-group t]
        ["First unread group" gnus-group-first-unread-group t]
        ["Best unread group" gnus-group-best-unread-group t])
       ["Transpose" gnus-group-transpose-groups
        (gnus-group-group-name)]
       ["Read a directory as a group..." gnus-group-enter-directory t]
       ))

    (easy-menu-define
     gnus-group-misc-menu gnus-group-mode-map ""
     '("Misc"
       ["Send a bug report" gnus-bug t]
       ["Send a mail" gnus-group-mail t]
       ["Post an article..." gnus-group-post-news t]
       ["Customize score file" gnus-score-customize t]
       ["Check for new news" gnus-group-get-new-news t]     
       ["Activate all groups" gnus-activate-all-groups t]
       ["Delete bogus groups" gnus-group-check-bogus-groups t]
       ["Find new newsgroups" gnus-find-new-newsgroups t]
       ["Restart Gnus" gnus-group-restart t]
       ["Read init file" gnus-group-read-init-file t]
       ["Browse foreign server" gnus-group-browse-foreign-server t]
       ["Enter server buffer" gnus-group-enter-server-mode t]
       ["Expire all expirable articles" gnus-group-expire-all-groups t]
       ["Generate any kiboze groups" nnkiboze-generate-groups t]
       ["Gnus version" gnus-version t]
       ["Save .newsrc files" gnus-group-save-newsrc t]
       ["Suspend Gnus" gnus-group-suspend t]
       ["Clear dribble buffer" gnus-group-clear-dribble t]
       ["Edit global kill file" gnus-group-edit-global-kill t]
       ["Read manual" gnus-info-find-node t]
       ["Toggle topics" gnus-topic-mode t]
       ("SOUP"
        ["Pack replies" nnsoup-pack-replies (fboundp 'nnsoup-request-group)]
        ["Send replies" gnus-soup-send-replies
         (fboundp 'gnus-soup-pack-packet)]
        ["Pack packet" gnus-soup-pack-packet (fboundp 'gnus-soup-pack-packet)]
        ["Save areas" gnus-soup-save-areas (fboundp 'gnus-soup-pack-packet)]
        ["Brew SOUP" gnus-soup-brew-soup (fboundp 'gnus-soup-pack-packet)])
       ["Exit from Gnus" gnus-group-exit t]
       ["Exit without saving" gnus-group-quit t]
       ))

    (run-hooks 'gnus-group-menu-hook)
    ))

(defun gnus-group-mode ()
  "Major mode for reading news.

All normal editing commands are switched off.
\\<gnus-group-mode-map>
The group buffer lists (some of) the groups available.  For instance,
`\\[gnus-group-list-groups]' will list all subscribed groups with unread articles, while `\\[gnus-group-list-zombies]'
lists all zombie groups.

Groups that are displayed can be entered with `\\[gnus-group-read-group]'.  To subscribe
to a group not displayed, type `\\[gnus-group-unsubscribe-group]'.

For more in-depth information on this mode, read the manual (`\\[gnus-info-find-node]').

The following commands are available:

\\{gnus-group-mode-map}"
  (interactive)
  (when (and menu-bar-mode
             (gnus-visual-p 'group-menu 'menu))
    (gnus-group-make-menu-bar))
  (kill-all-local-variables)
  (gnus-simplify-mode-line)
  (setq major-mode 'gnus-group-mode)
  (setq mode-name "Group")
  (gnus-group-set-mode-line)
  (setq mode-line-process nil)
  (use-local-map gnus-group-mode-map)
  (buffer-disable-undo (current-buffer))
  (setq truncate-lines t)
  (setq buffer-read-only t)
  (gnus-update-format-specifications nil 'group 'group-mode)
  (gnus-update-group-mark-positions)
  (gnus-make-local-hook 'post-command-hook)
  (gnus-add-hook 'post-command-hook 'gnus-clear-inboxes-moved nil t)
  (when gnus-use-undo
    (gnus-undo-mode 1))
  (run-hooks 'gnus-group-mode-hook))

(defun gnus-update-group-mark-positions ()
  (save-excursion
    (let ((gnus-process-mark 128)
          (gnus-group-marked '("dummy.group"))
          (gnus-active-hashtb (make-vector 10 0)))
      (gnus-set-active "dummy.group" '(0 . 0))
      (gnus-set-work-buffer)
      (gnus-group-insert-group-line "dummy.group" 0 nil 0 nil)
      (goto-char (point-min))
      (setq gnus-group-mark-positions
            (list (cons 'process (and (search-forward "\200" nil t)
                                      (- (point) 2))))))))

(defun gnus-clear-inboxes-moved ()
  (setq nnmail-moved-inboxes nil))

(defun gnus-mouse-pick-group (e)
  "Enter the group under the mouse pointer."
  (interactive "e")
  (mouse-set-point e)
  (gnus-group-read-group nil))

;; Look at LEVEL and find out what the level is really supposed to be.
;; If LEVEL is non-nil, LEVEL will be returned, if not, what happens
;; will depend on whether `gnus-group-use-permanent-levels' is used.
(defun gnus-group-default-level (&optional level number-or-nil)
  (cond
   (gnus-group-use-permanent-levels
    (or (setq gnus-group-use-permanent-levels
              (or level (if (numberp gnus-group-use-permanent-levels)
                            gnus-group-use-permanent-levels
                          (or gnus-group-default-list-level
                              gnus-level-subscribed))))
        gnus-group-default-list-level gnus-level-subscribed))
   (number-or-nil
    level)
   (t
    (or level gnus-group-default-list-level gnus-level-subscribed))))

(defun gnus-group-setup-buffer ()
  (switch-to-buffer gnus-group-buffer)
  (unless (eq major-mode 'gnus-group-mode)
    (gnus-add-current-to-buffer-list)
    (gnus-group-mode)
    (when gnus-carpal
      (gnus-carpal-setup-buffer 'group))))

(defun gnus-group-list-groups (&optional level unread lowest)
  "List newsgroups with level LEVEL or lower that have unread articles.
Default is all subscribed groups.
If argument UNREAD is non-nil, groups with no unread articles are also
listed."
  (interactive (list (if current-prefix-arg
                         (prefix-numeric-value current-prefix-arg)
                       (or
                        (gnus-group-default-level nil t)
                        gnus-group-default-list-level
                        gnus-level-subscribed))))
  (or level
      (setq level (car gnus-group-list-mode)
            unread (cdr gnus-group-list-mode)))
  (setq level (gnus-group-default-level level))
  (gnus-group-setup-buffer)             ;May call from out of group buffer
  (gnus-update-format-specifications)
  (let ((case-fold-search nil)
        (props (text-properties-at (gnus-point-at-bol)))
        (group (gnus-group-group-name)))
    (set-buffer gnus-group-buffer)
    (funcall gnus-group-prepare-function level unread lowest)
    (if (zerop (buffer-size))
        (gnus-message 5 gnus-no-groups-message)
      (goto-char (point-max))
      (when (or (not gnus-group-goto-next-group-function)
                (not (funcall gnus-group-goto-next-group-function 
                              group props)))
        (if (not group)
            ;; Go to the first group with unread articles.
            (gnus-group-search-forward t)
          ;; Find the right group to put point on.  If the current group
          ;; has disappeared in the new listing, try to find the next
          ;; one.        If no next one can be found, just leave point at the
          ;; first newsgroup in the buffer.
          (if (not (gnus-goto-char
                    (text-property-any
                     (point-min) (point-max)
                     'gnus-group (gnus-intern-safe group gnus-active-hashtb))))
              (let ((newsrc (cdddr (gnus-gethash group gnus-newsrc-hashtb))))
                (while (and newsrc
                            (not (gnus-goto-char
                                  (text-property-any
                                   (point-min) (point-max) 'gnus-group
                                   (gnus-intern-safe
                                    (caar newsrc) gnus-active-hashtb)))))
                  (setq newsrc (cdr newsrc)))
                (or newsrc (progn (goto-char (point-max))
                                  (forward-line -1)))))))
      ;; Adjust cursor point.
      (gnus-group-position-point))))

(defun gnus-group-list-level (level &optional all)
  "List groups on LEVEL.
If ALL (the prefix), also list groups that have no unread articles."
  (interactive "nList groups on level: \nP")
  (gnus-group-list-groups level all level))

(defun gnus-group-prepare-flat (level &optional all lowest regexp)
  "List all newsgroups with unread articles of level LEVEL or lower.
If ALL is non-nil, list groups that have no unread articles.
If LOWEST is non-nil, list all newsgroups of level LOWEST or higher.
If REGEXP, only list groups matching REGEXP."
  (set-buffer gnus-group-buffer)
  (let ((buffer-read-only nil)
        (newsrc (cdr gnus-newsrc-alist))
        (lowest (or lowest 1))
        info clevel unread group params)
    (erase-buffer)
    (if (< lowest gnus-level-zombie)
        ;; List living groups.
        (while newsrc
          (setq info (car newsrc)
                group (gnus-info-group info)
                params (gnus-info-params info)
                newsrc (cdr newsrc)
                unread (car (gnus-gethash group gnus-newsrc-hashtb)))
          (and unread                   ; This group might be bogus
               (or (not regexp)
                   (string-match regexp group))
               (<= (setq clevel (gnus-info-level info)) level)
               (>= clevel lowest)
               (or all                  ; We list all groups?
                   (if (eq unread t)    ; Unactivated?
                       gnus-group-list-inactive-groups ; We list unactivated 
                     (> unread 0))      ; We list groups with unread articles
                   (and gnus-list-groups-with-ticked-articles
                        (cdr (assq 'tick (gnus-info-marks info))))
                                        ; And groups with tickeds
                   ;; Check for permanent visibility.
                   (and gnus-permanently-visible-groups
                        (string-match gnus-permanently-visible-groups
                                      group))
                   (memq 'visible params)
                   (cdr (assq 'visible params)))
               (gnus-group-insert-group-line
                group (gnus-info-level info)
                (gnus-info-marks info) unread (gnus-info-method info)))))

    ;; List dead groups.
    (and (>= level gnus-level-zombie) (<= lowest gnus-level-zombie)
         (gnus-group-prepare-flat-list-dead
          (setq gnus-zombie-list (sort gnus-zombie-list 'string<))
          gnus-level-zombie ?Z
          regexp))
    (and (>= level gnus-level-killed) (<= lowest gnus-level-killed)
         (gnus-group-prepare-flat-list-dead
          (setq gnus-killed-list (sort gnus-killed-list 'string<))
          gnus-level-killed ?K regexp))

    (gnus-group-set-mode-line)
    (setq gnus-group-list-mode (cons level all))
    (run-hooks 'gnus-group-prepare-hook)))

(defun gnus-group-prepare-flat-list-dead (groups level mark regexp)
  ;; List zombies and killed lists somewhat faster, which was
  ;; suggested by Jack Vinson <vinson@unagi.cis.upenn.edu>.  It does
  ;; this by ignoring the group format specification altogether.
  (let (group)
    (if regexp
        ;; This loop is used when listing groups that match some
        ;; regexp.
        (while groups
          (setq group (pop groups))
          (when (string-match regexp group)
            (gnus-add-text-properties
             (point) (prog1 (1+ (point))
                       (insert " " mark "     *: " group "\n"))
             (list 'gnus-group (gnus-intern-safe group gnus-active-hashtb)
                   'gnus-unread t
                   'gnus-level level))))
      ;; This loop is used when listing all groups.
      (while groups
        (gnus-add-text-properties
         (point) (prog1 (1+ (point))
                   (insert " " mark "     *: "
                           (setq group (pop groups)) "\n"))
         (list 'gnus-group (gnus-intern-safe group gnus-active-hashtb)
               'gnus-unread t
               'gnus-level level))))))

(defun gnus-group-update-group-line ()
  "Update the current line in the group buffer."
  (let* ((buffer-read-only nil)
         (group (gnus-group-group-name))
         (entry (and group (gnus-gethash group gnus-newsrc-hashtb)))
         gnus-group-indentation)
    (when group
      (and entry
           (not (gnus-ephemeral-group-p group))
           (gnus-dribble-enter
            (concat "(gnus-group-set-info '"
                    (prin1-to-string (nth 2 entry)) ")")))
      (setq gnus-group-indentation (gnus-group-group-indentation))
      (gnus-delete-line)
      (gnus-group-insert-group-line-info group)
      (forward-line -1)
      (gnus-group-position-point))))

(defun gnus-group-insert-group-line-info (group)
  "Insert GROUP on the current line."
  (let ((entry (gnus-gethash group gnus-newsrc-hashtb))
        active info)
    (if entry
        (progn
          ;; (Un)subscribed group.
          (setq info (nth 2 entry))
          (gnus-group-insert-group-line
           group (gnus-info-level info) (gnus-info-marks info)
           (or (car entry) t) (gnus-info-method info)))
      ;; This group is dead.
      (gnus-group-insert-group-line
       group
       (if (member group gnus-zombie-list) gnus-level-zombie gnus-level-killed)
       nil
       (if (setq active (gnus-active group))
           (- (1+ (cdr active)) (car active)) 0)
       nil))))

(defun gnus-group-insert-group-line (gnus-tmp-group gnus-tmp-level 
                                                    gnus-tmp-marked number
                                                    gnus-tmp-method)
  "Insert a group line in the group buffer."
  (let* ((gnus-tmp-active (gnus-active gnus-tmp-group))
         (gnus-tmp-number-total
          (if gnus-tmp-active
              (1+ (- (cdr gnus-tmp-active) (car gnus-tmp-active)))
            0))
         (gnus-tmp-number-of-unread
          (if (numberp number) (int-to-string (max 0 number))
            "*"))
         (gnus-tmp-number-of-read
          (if (numberp number)
              (int-to-string (max 0 (- gnus-tmp-number-total number)))
            "*"))
         (gnus-tmp-subscribed
          (cond ((<= gnus-tmp-level gnus-level-subscribed) ? )
                ((<= gnus-tmp-level gnus-level-unsubscribed) ?U)
                ((= gnus-tmp-level gnus-level-zombie) ?Z)
                (t ?K)))
         (gnus-tmp-qualified-group (gnus-group-real-name gnus-tmp-group))
         (gnus-tmp-newsgroup-description
          (if gnus-description-hashtb
              (or (gnus-gethash gnus-tmp-group gnus-description-hashtb) "")
            ""))
         (gnus-tmp-moderated
          (if (member gnus-tmp-group gnus-moderated-list) ?m ? ))
         (gnus-tmp-moderated-string
          (if (eq gnus-tmp-moderated ?m) "(m)" ""))
         (gnus-tmp-method
          (gnus-server-get-method gnus-tmp-group gnus-tmp-method))
         (gnus-tmp-news-server (or (cadr gnus-tmp-method) ""))
         (gnus-tmp-news-method (or (car gnus-tmp-method) ""))
         (gnus-tmp-news-method-string
          (if gnus-tmp-method
              (format "(%s:%s)" (car gnus-tmp-method)
                      (cadr gnus-tmp-method)) ""))
         (gnus-tmp-marked-mark
          (if (and (numberp number)
                   (zerop number)
                   (cdr (assq 'tick gnus-tmp-marked)))
              ?* ? ))
         (gnus-tmp-process-marked
          (if (member gnus-tmp-group gnus-group-marked)
              gnus-process-mark ? ))
         (gnus-tmp-grouplens
          (or (and gnus-use-grouplens
                   (bbb-grouplens-group-p gnus-tmp-group))
              ""))
         (buffer-read-only nil)
         header gnus-tmp-header)        ; passed as parameter to user-funcs.
    (beginning-of-line)
    (gnus-add-text-properties
     (point)
     (prog1 (1+ (point))
       ;; Insert the text.
       (eval gnus-group-line-format-spec))
     `(gnus-group ,(gnus-intern-safe gnus-tmp-group gnus-active-hashtb)
       gnus-unread ,(if (numberp number)
                        (string-to-int gnus-tmp-number-of-unread)
                      t)
       gnus-marked ,gnus-tmp-marked-mark
       gnus-indentation ,gnus-group-indentation
       gnus-level ,gnus-tmp-level))
    (when (inline (gnus-visual-p 'group-highlight 'highlight))
      (forward-line -1)
      (run-hooks 'gnus-group-update-hook)
      (forward-line))
    ;; Allow XEmacs to remove front-sticky text properties.
    (gnus-group-remove-excess-properties)))

(defun gnus-group-highlight-line ()
  "Highlight the current line according to `gnus-group-highlight'."
  (let* ((list gnus-group-highlight)
         (p (point))
         (end (progn (end-of-line) (point)))
         ;; now find out where the line starts and leave point there.
         (beg (progn (beginning-of-line) (point)))
         (group (gnus-group-group-name))
         (entry (gnus-group-entry group))
         (unread (if (numberp (car entry)) (car entry) 0))
         (info (nth 2 entry))
         (method (gnus-server-get-method group (gnus-info-method info)))
         (marked (gnus-info-marks info))
         (mailp (memq 'mail (assoc (symbol-name
                                    (car (or method gnus-select-method)))
                                   gnus-valid-select-methods)))
         (level (or (gnus-info-level info) 9))
         (score (or (gnus-info-score info) 0))
         (ticked (gnus-range-length (cdr (assq 'tick marked))))
         (inhibit-read-only t))
    ;; Eval the cars of the lists until we find a match.
    (while (and list
                (not (eval (caar list))))
      (setq list (cdr list)))
    (let ((face (cdar list)))
      (unless (eq face (get-text-property beg 'face))
        (gnus-put-text-property 
         beg end 'face 
         (setq face (if (boundp face) (symbol-value face) face)))
        (gnus-extent-start-open beg)))
    (goto-char p)))

(defun gnus-group-update-group (group &optional visible-only)
  "Update all lines where GROUP appear.
If VISIBLE-ONLY is non-nil, the group won't be displayed if it isn't
already."
  (save-excursion
    (set-buffer gnus-group-buffer)
    ;; The buffer may be narrowed.
    (save-restriction
      (widen)
      (let ((ident (gnus-intern-safe group gnus-active-hashtb))
            (loc (point-min))
            found buffer-read-only)
        ;; Enter the current status into the dribble buffer.
        (let ((entry (gnus-gethash group gnus-newsrc-hashtb)))
          (if (and entry (not (gnus-ephemeral-group-p group)))
              (gnus-dribble-enter
               (concat "(gnus-group-set-info '" (prin1-to-string (nth 2 entry))
                       ")"))))
        ;; Find all group instances.  If topics are in use, each group
        ;; may be listed in more than once.
        (while (setq loc (text-property-any
                          loc (point-max) 'gnus-group ident))
          (setq found t)
          (goto-char loc)
          (let ((gnus-group-indentation (gnus-group-group-indentation)))
            (gnus-delete-line)
            (gnus-group-insert-group-line-info group)
            (save-excursion
              (forward-line -1)
              (run-hooks 'gnus-group-update-group-hook)))
          (setq loc (1+ loc)))
        (unless (or found visible-only)
          ;; No such line in the buffer, find out where it's supposed to
          ;; go, and insert it there (or at the end of the buffer).
          (if gnus-goto-missing-group-function
              (funcall gnus-goto-missing-group-function group)
            (let ((entry (cddr (gnus-gethash group gnus-newsrc-hashtb))))
              (while (and entry (car entry)
                          (not
                           (gnus-goto-char
                            (text-property-any
                             (point-min) (point-max)
                             'gnus-group (gnus-intern-safe
                                          (caar entry) gnus-active-hashtb)))))
                (setq entry (cdr entry)))
              (or entry (goto-char (point-max)))))
          ;; Finally insert the line.
          (let ((gnus-group-indentation (gnus-group-group-indentation)))
            (gnus-group-insert-group-line-info group)
            (save-excursion
              (forward-line -1)
              (run-hooks 'gnus-group-update-group-hook))))
        (gnus-group-set-mode-line)))))

(defun gnus-group-set-mode-line ()
  "Update the mode line in the group buffer."
  (when (memq 'group gnus-updated-mode-lines)
    ;; Yes, we want to keep this mode line updated.
    (save-excursion
      (set-buffer gnus-group-buffer)
      (let* ((gformat (or gnus-group-mode-line-format-spec
                          (setq gnus-group-mode-line-format-spec
                                (gnus-parse-format
                                 gnus-group-mode-line-format
                                 gnus-group-mode-line-format-alist))))
             (gnus-tmp-news-server (cadr gnus-select-method))
             (gnus-tmp-news-method (car gnus-select-method))
             (gnus-tmp-colon (if (equal gnus-tmp-news-server "") "" ":"))
             (max-len 60)
             gnus-tmp-header            ;Dummy binding for user-defined formats
             ;; Get the resulting string.
             (modified 
              (and gnus-dribble-buffer
                   (buffer-name gnus-dribble-buffer)
                   (buffer-modified-p gnus-dribble-buffer)
                   (save-excursion
                     (set-buffer gnus-dribble-buffer)
                     (not (zerop (buffer-size))))))
             (mode-string (eval gformat)))
        ;; Say whether the dribble buffer has been modified.
        (setq mode-line-modified
              (if modified "---*- " "----- "))
        ;; If the line is too long, we chop it off.
        (when (> (length mode-string) max-len)
          (setq mode-string (substring mode-string 0 (- max-len 4))))
        (prog1
            (setq mode-line-buffer-identification 
                  (gnus-mode-line-buffer-identification
                   (list mode-string)))
          (set-buffer-modified-p modified))))))

(defun gnus-group-group-name ()
  "Get the name of the newsgroup on the current line."
  (let ((group (get-text-property (gnus-point-at-bol) 'gnus-group)))
    (and group (symbol-name group))))

(defun gnus-group-group-level ()
  "Get the level of the newsgroup on the current line."
  (get-text-property (gnus-point-at-bol) 'gnus-level))

(defun gnus-group-group-indentation ()
  "Get the indentation of the newsgroup on the current line."
  (or (get-text-property (gnus-point-at-bol) 'gnus-indentation)
      (and gnus-group-indentation-function
           (funcall gnus-group-indentation-function))
      ""))

(defun gnus-group-group-unread ()
  "Get the number of unread articles of the newsgroup on the current line."
  (get-text-property (gnus-point-at-bol) 'gnus-unread))

(defun gnus-group-search-forward (&optional backward all level first-too)
  "Find the next newsgroup with unread articles.
If BACKWARD is non-nil, find the previous newsgroup instead.
If ALL is non-nil, just find any newsgroup.
If LEVEL is non-nil, find group with level LEVEL, or higher if no such
group exists.
If FIRST-TOO, the current line is also eligible as a target."
  (let ((way (if backward -1 1))
        (low gnus-level-killed)
        (beg (point))
        pos found lev)
    (if (and backward (progn (beginning-of-line)) (bobp))
        nil
      (or first-too (forward-line way))
      (while (and
              (not (eobp))
              (not (setq
                    found
                    (and (or all
                             (and
                              (let ((unread
                                     (get-text-property (point) 'gnus-unread)))
                                (and (numberp unread) (> unread 0)))
                              (setq lev (get-text-property (point)
                                                           'gnus-level))
                              (<= lev gnus-level-subscribed)))
                         (or (not level)
                             (and (setq lev (get-text-property (point)
                                                               'gnus-level))
                                  (or (= lev level)
                                      (and (< lev low)
                                           (< level lev)
                                           (progn
                                             (setq low lev)
                                             (setq pos (point))
                                             nil))))))))
              (zerop (forward-line way)))))
    (if found
        (progn (gnus-group-position-point) t)
      (goto-char (or pos beg))
      (and pos t))))

;;; Gnus group mode commands

;; Group marking.

(defun gnus-group-mark-group (n &optional unmark no-advance)
  "Mark the current group."
  (interactive "p")
  (let ((buffer-read-only nil)
        group)
    (while (and (> n 0)
                (not (eobp)))
      (when (setq group (gnus-group-group-name))
        ;; Go to the mark position.
        (beginning-of-line)
        (forward-char (or (cdr (assq 'process gnus-group-mark-positions)) 2))
        (subst-char-in-region
         (point) (1+ (point)) (following-char) 
         (if unmark
             (progn
               (setq gnus-group-marked (delete group gnus-group-marked))
               ? )
           (setq gnus-group-marked
                 (cons group (delete group gnus-group-marked)))
           gnus-process-mark)))
      (unless no-advance
        (gnus-group-next-group 1))
      (decf n))
    (gnus-summary-position-point)
    n))

(defun gnus-group-unmark-group (n)
  "Remove the mark from the current group."
  (interactive "p")
  (gnus-group-mark-group n 'unmark)
  (gnus-group-position-point))

(defun gnus-group-unmark-all-groups ()
  "Unmark all groups."
  (interactive)
  (let ((groups gnus-group-marked))
    (save-excursion
      (while groups
        (gnus-group-remove-mark (pop groups)))))
  (gnus-group-position-point))

(defun gnus-group-mark-region (unmark beg end)
  "Mark all groups between point and mark.
If UNMARK, remove the mark instead."
  (interactive "P\nr")
  (let ((num (count-lines beg end)))
    (save-excursion
      (goto-char beg)
      (- num (gnus-group-mark-group num unmark)))))

(defun gnus-group-mark-buffer (&optional unmark)
  "Mark all groups in the buffer.
If UNMARK, remove the mark instead."
  (interactive "P")
  (gnus-group-mark-region unmark (point-min) (point-max)))

(defun gnus-group-mark-regexp (regexp)
  "Mark all groups that match some regexp."
  (interactive "sMark (regexp): ")
  (let ((alist (cdr gnus-newsrc-alist))
        group)
    (while alist
      (when (string-match regexp (setq group (gnus-info-group (pop alist))))
        (gnus-group-set-mark group))))
  (gnus-group-position-point))

(defun gnus-group-remove-mark (group)
  "Remove the process mark from GROUP and move point there.
Return nil if the group isn't displayed."
  (if (gnus-group-goto-group group)
      (save-excursion
        (gnus-group-mark-group 1 'unmark t)
        t)
    (setq gnus-group-marked
          (delete group gnus-group-marked))
    nil))

(defun gnus-group-set-mark (group)
  "Set the process mark on GROUP."
  (if (gnus-group-goto-group group) 
      (save-excursion
        (gnus-group-mark-group 1 nil t))
    (setq gnus-group-marked (cons group (delete group gnus-group-marked)))))

(defun gnus-group-universal-argument (arg &optional groups func)
  "Perform any command on all groups accoring to the process/prefix convention."
  (interactive "P")
  (let ((groups (or groups (gnus-group-process-prefix arg)))
        group func)
    (if (eq (setq func (or func
                           (key-binding
                            (read-key-sequence
                             (substitute-command-keys
                              "\\<gnus-group-mode-map>\\[gnus-group-universal-argument]")))))
            'undefined)
        (gnus-error 1 "Undefined key")
      (while groups
        (gnus-group-remove-mark (setq group (pop groups)))
        (command-execute func))))
  (gnus-group-position-point))

(defun gnus-group-process-prefix (n)
  "Return a list of groups to work on.
Take into consideration N (the prefix) and the list of marked groups."
  (cond
   (n
    (setq n (prefix-numeric-value n))
    ;; There is a prefix, so we return a list of the N next
    ;; groups.
    (let ((way (if (< n 0) -1 1))
          (n (abs n))
          group groups)
      (save-excursion
        (while (and (> n 0)
                    (setq group (gnus-group-group-name)))
          (setq groups (cons group groups))
          (setq n (1- n))
          (gnus-group-next-group way)))
      (nreverse groups)))
   ((and (boundp 'transient-mark-mode)
         transient-mark-mode
         (boundp 'mark-active)
         mark-active)
    ;; Work on the region between point and mark.
    (let ((max (max (point) (mark)))
          groups)
      (save-excursion
        (goto-char (min (point) (mark)))
        (while
            (and
             (push (gnus-group-group-name) groups)
             (zerop (gnus-group-next-group 1))
             (< (point) max)))
        (nreverse groups))))
   (gnus-group-marked
    ;; No prefix, but a list of marked articles.
    (reverse gnus-group-marked))
   (t
    ;; Neither marked articles or a prefix, so we return the
    ;; current group.
    (let ((group (gnus-group-group-name)))
      (and group (list group))))))

;; Selecting groups.

(defun gnus-group-read-group (&optional all no-article group)
  "Read news in this newsgroup.
If the prefix argument ALL is non-nil, already read articles become
readable.  IF ALL is a number, fetch this number of articles.  If the
optional argument NO-ARTICLE is non-nil, no article will be
auto-selected upon group entry.  If GROUP is non-nil, fetch that
group."
  (interactive "P")
  (let ((group (or group (gnus-group-group-name)))
        number active marked entry)
    (or group (error "No group on current line"))
    (setq marked (nth 3 (nth 2 (setq entry (gnus-gethash
                                            group gnus-newsrc-hashtb)))))
    ;; This group might be a dead group.  In that case we have to get
    ;; the number of unread articles from `gnus-active-hashtb'.
    (setq number
          (cond ((numberp all) all)
                (entry (car entry))
                ((setq active (gnus-active group))
                 (- (1+ (cdr active)) (car active)))))
    (gnus-summary-read-group
     group (or all (and (numberp number)
                        (zerop (+ number (gnus-range-length 
                                          (cdr (assq 'tick marked)))
                                  (gnus-range-length
                                   (cdr (assq 'dormant marked)))))))
     no-article)))

(defun gnus-group-select-group (&optional all)
  "Select this newsgroup.
No article is selected automatically.
If ALL is non-nil, already read articles become readable.
If ALL is a number, fetch this number of articles."
  (interactive "P")
  (gnus-group-read-group all t))

(defun gnus-group-quick-select-group (&optional all)
  "Select the current group \"quickly\".
This means that no highlighting or scoring will be performed."
  (interactive "P")
  (let (gnus-visual
        gnus-score-find-score-files-function
        gnus-apply-kill-hook
        gnus-summary-expunge-below)
    (gnus-group-read-group all t)))

(defun gnus-group-visible-select-group (&optional all)
  "Select the current group without hiding any articles."
  (interactive "P")
  (let ((gnus-inhibit-limiting t))
    (gnus-group-read-group all t)))

;;;###autoload
(defun gnus-fetch-group (group)
  "Start Gnus if necessary and enter GROUP.
Returns whether the fetching was successful or not."
  (interactive "sGroup name: ")
  (or (get-buffer gnus-group-buffer)
      (gnus))
  (gnus-group-read-group nil nil group))

;; Enter a group that is not in the group buffer.  Non-nil is returned
;; if selection was successful.
(defun gnus-group-read-ephemeral-group
  (group method &optional activate quit-config request-only)
  "Read GROUP from METHOD as an ephemeral group.
If ACTIVATE, request the group first.
If QUIT-CONFIG, use that window configuration when
exiting from the ephemeral group.
If REQUEST-ONLY, don't actually read the group; just
request it.

Return the name of the group is selection was successful."
  (let ((group (if (gnus-group-foreign-p group) group
                 (gnus-group-prefixed-name group method))))
    (gnus-sethash
     group
     `(t nil (,group ,gnus-level-default-subscribed nil nil ,method
                     ((quit-config . ,(if quit-config quit-config
                                        (cons (current-buffer) 'summary))))))
     gnus-newsrc-hashtb)
    (set-buffer gnus-group-buffer)
    (unless (gnus-check-server method)
      (error "Unable to contact server: %s" (gnus-status-message method)))
    (when activate
      (unless (gnus-request-group group)
        (error "Couldn't request group")))
    (if request-only
        group
      (condition-case ()
          (when (gnus-group-read-group t t group)
            group)
        ;;(error nil)
        (quit nil)))))

(defun gnus-group-jump-to-group (group)
  "Jump to newsgroup GROUP."
  (interactive
   (list (completing-read
          "Group: " gnus-active-hashtb nil
          (gnus-read-active-file-p)
          nil
          'gnus-group-history)))

  (when (equal group "")
    (error "Empty group name"))

  (when (string-match "[\000-\032]" group)
    (error "Control characters in group: %s" group))

  (let ((b (text-property-any
            (point-min) (point-max)
            'gnus-group (gnus-intern-safe group gnus-active-hashtb))))
    (unless (gnus-ephemeral-group-p group)
      (if b
          ;; Either go to the line in the group buffer...
          (goto-char b)
        ;; ... or insert the line.
        (or
         t ;; Don't activate group.
         (gnus-active group)
         (gnus-activate-group group)
         (error "%s error: %s" group (gnus-status-message group)))

        (gnus-group-update-group group)
        (goto-char (text-property-any
                    (point-min) (point-max)
                    'gnus-group (gnus-intern-safe group gnus-active-hashtb)))))
    ;; Adjust cursor point.
    (gnus-group-position-point)))

(defun gnus-group-goto-group (group &optional far)
  "Goto to newsgroup GROUP.
If FAR, it is likely that the group is not on the current line."
  (when group
    (if far
        (gnus-goto-char
         (text-property-any 
          (point-min) (point-max)
          'gnus-group (gnus-intern-safe group gnus-active-hashtb)))
      (beginning-of-line)
      (cond
       ;; It's quite likely that we are on the right line, so
       ;; we check the current line first.
       ((eq (get-text-property (point) 'gnus-group)
            (gnus-intern-safe group gnus-active-hashtb))
        (point))
       ;; Previous and next line are also likely, so we check them as well.
       ((save-excursion
          (forward-line -1)
          (eq (get-text-property (point) 'gnus-group)
              (gnus-intern-safe group gnus-active-hashtb)))
        (forward-line -1)
        (point))
       ((save-excursion
          (forward-line 1)
          (eq (get-text-property (point) 'gnus-group)
              (gnus-intern-safe group gnus-active-hashtb)))
        (forward-line 1)
        (point))
       (t
        ;; Search through the entire buffer.
        (gnus-goto-char
         (text-property-any 
          (point-min) (point-max)
          'gnus-group (gnus-intern-safe group gnus-active-hashtb))))))))

(defun gnus-group-next-group (n &optional silent)
  "Go to next N'th newsgroup.
If N is negative, search backward instead.
Returns the difference between N and the number of skips actually
done."
  (interactive "p")
  (gnus-group-next-unread-group n t nil silent))

(defun gnus-group-next-unread-group (n &optional all level silent)
  "Go to next N'th unread newsgroup.
If N is negative, search backward instead.
If ALL is non-nil, choose any newsgroup, unread or not.
If LEVEL is non-nil, choose the next group with level LEVEL, or, if no
such group can be found, the next group with a level higher than
LEVEL.
Returns the difference between N and the number of skips actually
made."
  (interactive "p")
  (let ((backward (< n 0))
        (n (abs n)))
    (while (and (> n 0)
                (gnus-group-search-forward
                 backward (or (not gnus-group-goto-unread) all) level))
      (setq n (1- n)))
    (when (and (/= 0 n)
               (not silent))
      (gnus-message 7 "No more%s newsgroups%s" (if all "" " unread")
                    (if level " on this level or higher" "")))
    n))

(defun gnus-group-prev-group (n)
  "Go to previous N'th newsgroup.
Returns the difference between N and the number of skips actually
done."
  (interactive "p")
  (gnus-group-next-unread-group (- n) t))

(defun gnus-group-prev-unread-group (n)
  "Go to previous N'th unread newsgroup.
Returns the difference between N and the number of skips actually
done."
  (interactive "p")
  (gnus-group-next-unread-group (- n)))

(defun gnus-group-next-unread-group-same-level (n)
  "Go to next N'th unread newsgroup on the same level.
If N is negative, search backward instead.
Returns the difference between N and the number of skips actually
done."
  (interactive "p")
  (gnus-group-next-unread-group n t (gnus-group-group-level))
  (gnus-group-position-point))

(defun gnus-group-prev-unread-group-same-level (n)
  "Go to next N'th unread newsgroup on the same level.
Returns the difference between N and the number of skips actually
done."
  (interactive "p")
  (gnus-group-next-unread-group (- n) t (gnus-group-group-level))
  (gnus-group-position-point))

(defun gnus-group-best-unread-group (&optional exclude-group)
  "Go to the group with the highest level.
If EXCLUDE-GROUP, do not go to that group."
  (interactive)
  (goto-char (point-min))
  (let ((best 100000)
        unread best-point)
    (while (not (eobp))
      (setq unread (get-text-property (point) 'gnus-unread))
      (if (and (numberp unread) (> unread 0))
          (progn
            (if (and (get-text-property (point) 'gnus-level)
                     (< (get-text-property (point) 'gnus-level) best)
                     (or (not exclude-group)
                         (not (equal exclude-group (gnus-group-group-name)))))
                (progn
                  (setq best (get-text-property (point) 'gnus-level))
                  (setq best-point (point))))))
      (forward-line 1))
    (if best-point (goto-char best-point))
    (gnus-summary-position-point)
    (and best-point (gnus-group-group-name))))

(defun gnus-group-first-unread-group ()
  "Go to the first group with unread articles."
  (interactive)
  (prog1
      (let ((opoint (point))
            unread)
        (goto-char (point-min))
        (if (or (eq (setq unread (gnus-group-group-unread)) t) ; Not active.
                (and (numberp unread)   ; Not a topic.
                     (not (zerop unread))) ; Has unread articles.
                (zerop (gnus-group-next-unread-group 1))) ; Next unread group.
            (point)                     ; Success.
          (goto-char opoint)
          nil))                         ; Not success.
    (gnus-group-position-point)))

(defun gnus-group-enter-server-mode ()
  "Jump to the server buffer."
  (interactive)
  (gnus-enter-server-buffer))

(defun gnus-group-make-group (name &optional method address)
  "Add a new newsgroup.
The user will be prompted for a NAME, for a select METHOD, and an
ADDRESS."
  (interactive
   (list
    (read-string "Group name: ")
    (gnus-read-method "From method: ")))

  (let* ((meth (when (and method
                          (not (gnus-server-equal method gnus-select-method)))
                 (if address (list (intern method) address)
                   method)))
         (nname (if method (gnus-group-prefixed-name name meth) name))
         backend info)
    (when (gnus-gethash nname gnus-newsrc-hashtb)
      (error "Group %s already exists" nname))
    ;; Subscribe to the new group.
    (gnus-group-change-level
     (setq info (list t nname gnus-level-default-subscribed nil nil meth))
     gnus-level-default-subscribed gnus-level-killed
     (and (gnus-group-group-name)
          (gnus-gethash (gnus-group-group-name)
                        gnus-newsrc-hashtb))
     t)
    ;; Make it active.
    (gnus-set-active nname (cons 1 0))
    (or (gnus-ephemeral-group-p name)
        (gnus-dribble-enter
         (concat "(gnus-group-set-info '" (prin1-to-string (cdr info)) ")")))
    ;; Insert the line.
    (gnus-group-insert-group-line-info nname)
    (forward-line -1)
    (gnus-group-position-point)

    ;; Load the backend and try to make the backend create
    ;; the group as well.
    (when (assoc (symbol-name (setq backend (car (gnus-server-get-method
                                                  nil meth))))
                 gnus-valid-select-methods)
      (require backend))
    (gnus-check-server meth)
    (and (gnus-check-backend-function 'request-create-group nname)
         (gnus-request-create-group nname))
    t))

(defun gnus-group-delete-group (group &optional force)
  "Delete the current group.  Only meaningful with mail groups.
If FORCE (the prefix) is non-nil, all the articles in the group will
be deleted.  This is \"deleted\" as in \"removed forever from the face
of the Earth\".  There is no undo.  The user will be prompted before
doing the deletion."
  (interactive
   (list (gnus-group-group-name)
         current-prefix-arg))
  (or group (error "No group to rename"))
  (or (gnus-check-backend-function 'request-delete-group group)
      (error "This backend does not support group deletion"))
  (prog1
      (if (not (gnus-yes-or-no-p
                (format
                 "Do you really want to delete %s%s? "
                 group (if force " and all its contents" ""))))
          () ; Whew!
        (gnus-message 6 "Deleting group %s..." group)
        (if (not (gnus-request-delete-group group force))
            (gnus-error 3 "Couldn't delete group %s" group)
          (gnus-message 6 "Deleting group %s...done" group)
          (gnus-group-goto-group group)
          (gnus-group-kill-group 1 t)
          (gnus-sethash group nil gnus-active-hashtb)
          t))
    (gnus-group-position-point)))

(defun gnus-group-rename-group (group new-name)
  "Rename group from GROUP to NEW-NAME.
When used interactively, GROUP is the group under point
and NEW-NAME will be prompted for."
  (interactive
   (list
    (gnus-group-group-name)
    (progn
      (unless (gnus-check-backend-function
               'request-rename-group (gnus-group-group-name))
        (error "This backend does not support renaming groups"))
      (read-string "New group name: " (gnus-group-group-name)))))

  (unless (gnus-check-backend-function 'request-rename-group group)
    (error "This backend does not support renaming groups"))
  (unless group 
    (error "No group to rename"))
  (when (string-match "^[ \t]*$" new-name)
    (error "Not a valid group name"))
  (when (equal group new-name)
    (error "Can't rename to the same name"))

  ;; We find the proper prefixed name.
  (setq new-name
        (if (equal (gnus-group-real-name new-name) new-name)
            ;; Native group.
            new-name
          ;; Foreign group.
          (gnus-group-prefixed-name
           (gnus-group-real-name new-name)
           (gnus-info-method (gnus-get-info group)))))

  (gnus-message 6 "Renaming group %s to %s..." group new-name)
  (prog1
      (if (not (gnus-request-rename-group group new-name))
          (gnus-error 3 "Couldn't rename group %s to %s" group new-name)
        ;; We rename the group internally by killing it...
        (gnus-group-goto-group group)
        (gnus-group-kill-group)
        ;; ... changing its name ...
        (setcar (cdar gnus-list-of-killed-groups) new-name)
        ;; ... and then yanking it.  Magic!
        (gnus-group-yank-group)
        (gnus-set-active new-name (gnus-active group))
        (gnus-message 6 "Renaming group %s to %s...done" group new-name)
        new-name)
    (gnus-group-position-point)))

(defun gnus-group-edit-group (group &optional part)
  "Edit the group on the current line."
  (interactive (list (gnus-group-group-name)))
  (let ((part (or part 'info))
        info)
    (unless group
      (error "No group on current line"))
    (unless (setq info (gnus-get-info group))
      (error "Killed group; can't be edited"))
    (gnus-edit-form
     ;; Find the proper form to edit.
     (cond ((eq part 'method)
            (or (gnus-info-method info) "native"))
           ((eq part 'params)
            (gnus-info-params info))
           (t info))
     ;; The proper documentation.
     (format
      "Editing the %s."
      (cond
       ((eq part 'method) "select method")
       ((eq part 'params) "group parameters")
       (t "group info")))
     `(lambda (form)
        (gnus-group-edit-group-done ',part ,group form)))))

(defun gnus-group-edit-group-method (group)
  "Edit the select method of GROUP."
  (interactive (list (gnus-group-group-name)))
  (gnus-group-edit-group group 'method))

(defun gnus-group-edit-group-parameters (group)
  "Edit the group parameters of GROUP."
  (interactive (list (gnus-group-group-name)))
  (gnus-group-edit-group group 'params))

(defun gnus-group-edit-group-done (part group form)
  "Update variables."
  (let* ((method (cond ((eq part 'info) (nth 4 form))
                       ((eq part 'method) form)
                       (t nil)))
         (info (cond ((eq part 'info) form)
                     ((eq part 'method) (gnus-get-info group))
                     (t nil)))
         (new-group (if info
                        (if (or (not method)
                                (gnus-server-equal
                                 gnus-select-method method))
                            (gnus-group-real-name (car info))
                          (gnus-group-prefixed-name
                           (gnus-group-real-name (car info)) method))
                      nil)))
    (when (and new-group
               (not (equal new-group group)))
      (when (gnus-group-goto-group group)
        (gnus-group-kill-group 1))
      (gnus-activate-group new-group))
    ;; Set the info.
    (if (not (and info new-group))
        (gnus-group-set-info form (or new-group group) part)
      (setq info (gnus-copy-sequence info))
      (setcar info new-group)
      (unless (gnus-server-equal method "native")
        (unless (nthcdr 3 info)
          (nconc info (list nil nil)))
        (unless (nthcdr 4 info)
          (nconc info (list nil)))
        (gnus-info-set-method info method))
      (gnus-group-set-info info))
    (gnus-group-update-group (or new-group group))
    (gnus-group-position-point)))

(defun gnus-group-make-help-group ()
  "Create the Gnus documentation group."
  (interactive)
  (let ((path load-path)
        (name (gnus-group-prefixed-name "gnus-help" '(nndoc "gnus-help")))
        file dir)
    (and (gnus-gethash name gnus-newsrc-hashtb)
         (error "Documentation group already exists"))
    (while path
      (setq dir (file-name-as-directory (expand-file-name (pop path)))
            file nil)
      (when (or (file-exists-p (setq file (concat dir "gnus-tut.txt")))
                (file-exists-p
                 (setq file (concat (file-name-directory
                                     (directory-file-name dir))
                                    "etc/gnus-tut.txt"))))
        (setq path nil)))
    (if (not file)
        (gnus-message 1 "Couldn't find doc group")
      (gnus-group-make-group
       (gnus-group-real-name name)
       (list 'nndoc "gnus-help"
             (list 'nndoc-address file)
             (list 'nndoc-article-type 'mbox)))))
  (gnus-group-position-point))

(defun gnus-group-make-doc-group (file type)
  "Create a group that uses a single file as the source."
  (interactive
   (list (read-file-name "File name: ")
         (and current-prefix-arg 'ask)))
  (when (eq type 'ask)
    (let ((err "")
          char found)
      (while (not found)
        (message
         "%sFile type (mbox, babyl, digest, forward, mmfd, guess) [mbdfag]: "
         err)
        (setq found (cond ((= (setq char (read-char)) ?m) 'mbox)
                          ((= char ?b) 'babyl)
                          ((= char ?d) 'digest)
                          ((= char ?f) 'forward)
                          ((= char ?a) 'mmfd)
                          (t (setq err (format "%c unknown. " char))
                             nil))))
      (setq type found)))
  (let* ((file (expand-file-name file))
         (name (gnus-generate-new-group-name
                (gnus-group-prefixed-name
                 (file-name-nondirectory file) '(nndoc "")))))
    (gnus-group-make-group
     (gnus-group-real-name name)
     (list 'nndoc file
           (list 'nndoc-address file)
           (list 'nndoc-article-type (or type 'guess))))))

(defun gnus-group-make-archive-group (&optional all)
  "Create the (ding) Gnus archive group of the most recent articles.
Given a prefix, create a full group."
  (interactive "P")
  (let ((group (gnus-group-prefixed-name
                (if all "ding.archives" "ding.recent") '(nndir ""))))
    (when (gnus-gethash group gnus-newsrc-hashtb)
      (error "Archive group already exists"))
    (gnus-group-make-group
     (gnus-group-real-name group)
     (list 'nndir (if all "hpc" "edu")
           (list 'nndir-directory
                 (if all gnus-group-archive-directory
                   gnus-group-recent-archive-directory))))
    (gnus-group-add-parameter group (cons 'to-address "ding@ifi.uio.no"))))

(defun gnus-group-make-directory-group (dir)
  "Create an nndir group.
The user will be prompted for a directory.  The contents of this
directory will be used as a newsgroup.  The directory should contain
mail messages or news articles in files that have numeric names."
  (interactive
   (list (read-file-name "Create group from directory: ")))
  (or (file-exists-p dir) (error "No such directory"))
  (or (file-directory-p dir) (error "Not a directory"))
  (let ((ext "")
        (i 0)
        group)
    (while (or (not group) (gnus-gethash group gnus-newsrc-hashtb))
      (setq group
            (gnus-group-prefixed-name
             (concat (file-name-as-directory (directory-file-name dir))
                     ext)
             '(nndir "")))
      (setq ext (format "<%d>" (setq i (1+ i)))))
    (gnus-group-make-group
     (gnus-group-real-name group)
     (list 'nndir (gnus-group-real-name group) (list 'nndir-directory dir)))))

(defun gnus-group-make-kiboze-group (group address scores)
  "Create an nnkiboze group.
The user will be prompted for a name, a regexp to match groups, and
score file entries for articles to include in the group."
  (interactive
   (list
    (read-string "nnkiboze group name: ")
    (read-string "Source groups (regexp): ")
    (let ((headers (mapcar (lambda (group) (list group))
                           '("subject" "from" "number" "date" "message-id"
                             "references" "chars" "lines" "xref"
                             "followup" "all" "body" "head")))
          scores header regexp regexps)
      (while (not (equal "" (setq header (completing-read
                                          "Match on header: " headers nil t))))
        (setq regexps nil)
        (while (not (equal "" (setq regexp (read-string
                                            (format "Match on %s (string): "
                                                    header)))))
          (setq regexps (cons (list regexp nil nil 'r) regexps)))
        (setq scores (cons (cons header regexps) scores)))
      scores)))
  (gnus-group-make-group group "nnkiboze" address)
  (nnheader-temp-write (gnus-score-file-name (concat "nnkiboze:" group))
    (let (emacs-lisp-mode-hook)
      (pp scores (current-buffer)))))

(defun gnus-group-add-to-virtual (n vgroup)
  "Add the current group to a virtual group."
  (interactive
   (list current-prefix-arg
         (completing-read "Add to virtual group: " gnus-newsrc-hashtb nil t
                          "nnvirtual:")))
  (or (eq (car (gnus-find-method-for-group vgroup)) 'nnvirtual)
      (error "%s is not an nnvirtual group" vgroup))
  (let* ((groups (gnus-group-process-prefix n))
         (method (gnus-info-method (gnus-get-info vgroup))))
    (setcar (cdr method)
            (concat
             (nth 1 method) "\\|"
             (mapconcat
              (lambda (s)
                (gnus-group-remove-mark s)
                (concat "\\(^" (regexp-quote s) "$\\)"))
              groups "\\|"))))
  (gnus-group-position-point))

(defun gnus-group-make-empty-virtual (group)
  "Create a new, fresh, empty virtual group."
  (interactive "sCreate new, empty virtual group: ")
  (let* ((method (list 'nnvirtual "^$"))
         (pgroup (gnus-group-prefixed-name group method)))
    ;; Check whether it exists already.
    (and (gnus-gethash pgroup gnus-newsrc-hashtb)
         (error "Group %s already exists." pgroup))
    ;; Subscribe the new group after the group on the current line.
    (gnus-subscribe-group pgroup (gnus-group-group-name) method)
    (gnus-group-update-group pgroup)
    (forward-line -1)
    (gnus-group-position-point)))

(defun gnus-group-enter-directory (dir)
  "Enter an ephemeral nneething group."
  (interactive "DDirectory to read: ")
  (let* ((method (list 'nneething dir))
         (leaf (gnus-group-prefixed-name
                (file-name-nondirectory (directory-file-name dir))
                method))
         (name (gnus-generate-new-group-name leaf)))
    (let ((nneething-read-only t))
      (or (gnus-group-read-ephemeral-group
           name method t
           (cons (current-buffer) (if (eq major-mode 'gnus-summary-mode)
                                      'summary 'group)))
          (error "Couldn't enter %s" dir)))))

;; Group sorting commands
;; Suggested by Joe Hildebrand <hildjj@idaho.fuentez.com>.

(defun gnus-group-sort-groups (func &optional reverse)
  "Sort the group buffer according to FUNC.
If REVERSE, reverse the sorting order."
  (interactive (list gnus-group-sort-function
                     current-prefix-arg))
  (let ((func (cond 
               ((not (listp func)) func)
               ((null func) func)
               ((= 1 (length func)) (car func))
               (t `(lambda (t1 t2)
                     ,(gnus-make-sort-function 
                       (reverse func)))))))
    ;; We peel off the dummy group from the alist.
    (when func
      (when (equal (car (gnus-info-group gnus-newsrc-alist)) "dummy.group")
        (pop gnus-newsrc-alist))
      ;; Do the sorting.
      (setq gnus-newsrc-alist
            (sort gnus-newsrc-alist func))
      (when reverse
        (setq gnus-newsrc-alist (nreverse gnus-newsrc-alist)))
      ;; Regenerate the hash table.
      (gnus-make-hashtable-from-newsrc-alist)
      (gnus-group-list-groups))))

(defun gnus-group-sort-groups-by-alphabet (&optional reverse)
  "Sort the group buffer alphabetically by group name.
If REVERSE, sort in reverse order."
  (interactive "P")
  (gnus-group-sort-groups 'gnus-group-sort-by-alphabet reverse))

(defun gnus-group-sort-groups-by-unread (&optional reverse)
  "Sort the group buffer by number of unread articles.
If REVERSE, sort in reverse order."
  (interactive "P")
  (gnus-group-sort-groups 'gnus-group-sort-by-unread reverse))

(defun gnus-group-sort-groups-by-level (&optional reverse)
  "Sort the group buffer by group level.
If REVERSE, sort in reverse order."
  (interactive "P")
  (gnus-group-sort-groups 'gnus-group-sort-by-level reverse))

(defun gnus-group-sort-groups-by-score (&optional reverse)
  "Sort the group buffer by group score.
If REVERSE, sort in reverse order."
  (interactive "P")
  (gnus-group-sort-groups 'gnus-group-sort-by-score reverse))

(defun gnus-group-sort-groups-by-rank (&optional reverse)
  "Sort the group buffer by group rank.
If REVERSE, sort in reverse order."
  (interactive "P")
  (gnus-group-sort-groups 'gnus-group-sort-by-rank reverse))

(defun gnus-group-sort-groups-by-method (&optional reverse)
  "Sort the group buffer alphabetically by backend name.
If REVERSE, sort in reverse order."
  (interactive "P")
  (gnus-group-sort-groups 'gnus-group-sort-by-method reverse))

(defun gnus-group-sort-by-alphabet (info1 info2)
  "Sort alphabetically."
  (string< (gnus-info-group info1) (gnus-info-group info2)))

(defun gnus-group-sort-by-unread (info1 info2)
  "Sort by number of unread articles."
  (let ((n1 (car (gnus-gethash (gnus-info-group info1) gnus-newsrc-hashtb)))
        (n2 (car (gnus-gethash (gnus-info-group info2) gnus-newsrc-hashtb))))
    (< (or (and (numberp n1) n1) 0)
       (or (and (numberp n2) n2) 0))))

(defun gnus-group-sort-by-level (info1 info2)
  "Sort by level."
  (< (gnus-info-level info1) (gnus-info-level info2)))

(defun gnus-group-sort-by-method (info1 info2)
  "Sort alphabetically by backend name."
  (string< (symbol-name (car (gnus-find-method-for-group
                              (gnus-info-group info1) info1)))
           (symbol-name (car (gnus-find-method-for-group
                              (gnus-info-group info2) info2)))))

(defun gnus-group-sort-by-score (info1 info2)
  "Sort by group score."
  (< (gnus-info-score info1) (gnus-info-score info2)))

(defun gnus-group-sort-by-rank (info1 info2)
  "Sort by level and score."
  (let ((level1 (gnus-info-level info1))
        (level2 (gnus-info-level info2)))
    (or (< level1 level2)
        (and (= level1 level2)
             (> (gnus-info-score info1) (gnus-info-score info2))))))

;;; Clearing data

(defun gnus-group-clear-data (n)
  "Clear all marks and read ranges from the current group."
  (interactive "P")
  (let ((groups (gnus-group-process-prefix n))
        group info)
    (while (setq group (pop groups))
      (gnus-info-clear-data (setq info (gnus-get-info group)))
      (gnus-get-unread-articles-in-group info (gnus-active group) t)
      (when (gnus-group-goto-group group)
        (gnus-group-remove-mark group)
        (gnus-group-update-group-line)))))

(defun gnus-group-clear-data-on-native-groups ()
  "Clear all marks and read ranges from all native groups."
  (interactive)
  (when (gnus-yes-or-no-p "Really clear all data from almost all groups? ")
    (let ((alist (cdr gnus-newsrc-alist))
          info)
      (while (setq info (pop alist))
        (gnus-info-clear-data info))
      (gnus-get-unread-articles))))

(defun gnus-info-clear-data (info)
  "Clear all marks and read ranges from INFO."
  (let ((group (gnus-info-group info)))
    (gnus-undo-register
      `(progn
         (gnus-info-set-marks ,info ,(gnus-info-marks info))
         (gnus-info-set-read ,info ,(gnus-info-read info))
         (when (gnus-group-goto-group ,group)
           (gnus-group-update-group-line))))
    (gnus-info-set-read info nil)
    (when (gnus-info-marks info)
      (gnus-info-set-marks info nil))))

;; Group catching up.

(defun gnus-group-catchup-current (&optional n all)
  "Mark all articles not marked as unread in current newsgroup as read.
If prefix argument N is numeric, the ARG next newsgroups will be
caught up.  If ALL is non-nil, marked articles will also be marked as
read.  Cross references (Xref: header) of articles are ignored.
The difference between N and actual number of newsgroups that were
caught up is returned."
  (interactive "P")
  (unless (gnus-group-group-name)
    (error "No group on the current line"))
  (if (not (or (not gnus-interactive-catchup) ;Without confirmation?
               gnus-expert-user
               (gnus-y-or-n-p
                (if all
                    "Do you really want to mark all articles as read? "
                  "Mark all unread articles as read? "))))
      n
    (let ((groups (gnus-group-process-prefix n))
          (ret 0))
      (while groups
        ;; Virtual groups have to be given special treatment.
        (let ((method (gnus-find-method-for-group (car groups))))
          (if (eq 'nnvirtual (car method))
              (nnvirtual-catchup-group
               (gnus-group-real-name (car groups)) (nth 1 method) all)))
        (gnus-group-remove-mark (car groups))
        (if (>= (gnus-group-group-level) gnus-level-zombie)
            (gnus-message 2 "Dead groups can't be caught up")
          (if (prog1
                  (gnus-group-goto-group (car groups))
                (gnus-group-catchup (car groups) all))
              (gnus-group-update-group-line)
            (setq ret (1+ ret))))
        (setq groups (cdr groups)))
      (gnus-group-next-unread-group 1)
      ret)))

(defun gnus-group-catchup-current-all (&optional n)
  "Mark all articles in current newsgroup as read.
Cross references (Xref: header) of articles are ignored."
  (interactive "P")
  (gnus-group-catchup-current n 'all))

(defun gnus-group-catchup (group &optional all)
  "Mark all articles in GROUP as read.
If ALL is non-nil, all articles are marked as read.
The return value is the number of articles that were marked as read,
or nil if no action could be taken."
  (let* ((entry (gnus-gethash group gnus-newsrc-hashtb))
         (num (car entry)))
    ;; Do the updating only if the newsgroup isn't killed.
    (if (not (numberp (car entry)))
        (gnus-message 1 "Can't catch up; non-active group")
      ;; Do auto-expirable marks if that's required.
      (when (gnus-group-auto-expirable-p group)
        (gnus-add-marked-articles
         group 'expire (gnus-list-of-unread-articles group))
        (when all
          (let ((marks (nth 3 (nth 2 entry))))
            (gnus-add-marked-articles
             group 'expire (gnus-uncompress-range (cdr (assq 'tick marks))))
            (gnus-add-marked-articles
             group 'expire (gnus-uncompress-range (cdr (assq 'tick marks)))))))
      (when entry
        (gnus-update-read-articles group nil)
        ;; Also nix out the lists of marks and dormants.
        (when all
          (gnus-add-marked-articles group 'tick nil nil 'force)
          (gnus-add-marked-articles group 'dormant nil nil 'force))
        (run-hooks 'gnus-group-catchup-group-hook)
        num))))

(defun gnus-group-expire-articles (&optional n)
  "Expire all expirable articles in the current newsgroup."
  (interactive "P")
  (let ((groups (gnus-group-process-prefix n))
        group)
    (unless groups
      (error "No groups to expire"))
    (while (setq group (pop groups))
      (gnus-group-remove-mark group)
      (when (gnus-check-backend-function 'request-expire-articles group)
        (gnus-message 6 "Expiring articles in %s..." group)
        (let* ((info (gnus-get-info group))
               (expirable (if (gnus-group-total-expirable-p group)
                              (cons nil (gnus-list-of-read-articles group))
                            (assq 'expire (gnus-info-marks info))))
               (expiry-wait (gnus-group-find-parameter group 'expiry-wait)))
          (when expirable
            (setcdr
             expirable
             (gnus-compress-sequence
              (if expiry-wait
                  ;; We set the expiry variables to the groupp
                  ;; parameter. 
                  (let ((nnmail-expiry-wait-function nil)
                        (nnmail-expiry-wait expiry-wait))
                    (gnus-request-expire-articles
                     (gnus-uncompress-sequence (cdr expirable)) group))
                ;; Just expire using the normal expiry values.
                (gnus-request-expire-articles
                 (gnus-uncompress-sequence (cdr expirable)) group))))
            (gnus-close-group group))
          (gnus-message 6 "Expiring articles in %s...done" group)))
      (gnus-group-position-point))))

(defun gnus-group-expire-all-groups ()
  "Expire all expirable articles in all newsgroups."
  (interactive)
  (save-excursion
    (gnus-message 5 "Expiring...")
    (let ((gnus-group-marked (mapcar (lambda (info) (gnus-info-group info))
                                     (cdr gnus-newsrc-alist))))
      (gnus-group-expire-articles nil)))
  (gnus-group-position-point)
  (gnus-message 5 "Expiring...done"))

(defun gnus-group-set-current-level (n level)
  "Set the level of the next N groups to LEVEL."
  (interactive
   (list
    current-prefix-arg
    (string-to-int
     (let ((s (read-string
               (format "Level (default %s): "
                       (or (gnus-group-group-level) 
                           gnus-level-default-subscribed)))))
       (if (string-match "^\\s-*$" s)
           (int-to-string (or (gnus-group-group-level) 
                              gnus-level-default-subscribed))
         s)))))
  (or (and (>= level 1) (<= level gnus-level-killed))
      (error "Illegal level: %d" level))
  (let ((groups (gnus-group-process-prefix n))
        group)
    (while (setq group (pop groups))
      (gnus-group-remove-mark group)
      (gnus-message 6 "Changed level of %s from %d to %d"
                    group (or (gnus-group-group-level) gnus-level-killed)
                    level)
      (gnus-group-change-level
       group level (or (gnus-group-group-level) gnus-level-killed))
      (gnus-group-update-group-line)))
  (gnus-group-position-point))

(defun gnus-group-unsubscribe-current-group (&optional n)
  "Toggle subscription of the current group.
If given numerical prefix, toggle the N next groups."
  (interactive "P")
  (let ((groups (gnus-group-process-prefix n))
        group)
    (while groups
      (setq group (car groups)
            groups (cdr groups))
      (gnus-group-remove-mark group)
      (gnus-group-unsubscribe-group
       group (if (<= (gnus-group-group-level) gnus-level-subscribed)
                 gnus-level-default-unsubscribed
               gnus-level-default-subscribed) t)
      (gnus-group-update-group-line))
    (gnus-group-next-group 1)))

(defun gnus-group-unsubscribe-group (group &optional level silent)
  "Toggle subscription to GROUP.
Killed newsgroups are subscribed.  If SILENT, don't try to update the
group line."
  (interactive
   (list (completing-read
          "Group: " gnus-active-hashtb nil
          (gnus-read-active-file-p)
          nil 
          'gnus-group-history)))
  (let ((newsrc (gnus-gethash group gnus-newsrc-hashtb)))
    (cond
     ((string-match "^[ \t]$" group)
      (error "Empty group name"))
     (newsrc
      ;; Toggle subscription flag.
      (gnus-group-change-level
       newsrc (if level level (if (<= (nth 1 (nth 2 newsrc))
                                      gnus-level-subscribed)
                                  (1+ gnus-level-subscribed)
                                gnus-level-default-subscribed)))
      (unless silent
        (gnus-group-update-group group)))
     ((and (stringp group)
           (or (not (gnus-read-active-file-p))
               (gnus-active group)))
      ;; Add new newsgroup.
      (gnus-group-change-level
       group
       (if level level gnus-level-default-subscribed)
       (or (and (member group gnus-zombie-list)
                gnus-level-zombie)
           gnus-level-killed)
       (and (gnus-group-group-name)
            (gnus-gethash (gnus-group-group-name) gnus-newsrc-hashtb)))
      (unless silent
        (gnus-group-update-group group)))
     (t (error "No such newsgroup: %s" group)))
    (gnus-group-position-point)))

(defun gnus-group-transpose-groups (n)
  "Move the current newsgroup up N places.
If given a negative prefix, move down instead.  The difference between
N and the number of steps taken is returned."
  (interactive "p")
  (or (gnus-group-group-name)
      (error "No group on current line"))
  (gnus-group-kill-group 1)
  (prog1
      (forward-line (- n))
    (gnus-group-yank-group)
    (gnus-group-position-point)))

(defun gnus-group-kill-all-zombies ()
  "Kill all zombie newsgroups."
  (interactive)
  (setq gnus-killed-list (nconc gnus-zombie-list gnus-killed-list))
  (setq gnus-zombie-list nil)
  (gnus-group-list-groups))

(defun gnus-group-kill-region (begin end)
  "Kill newsgroups in current region (excluding current point).
The killed newsgroups can be yanked by using \\[gnus-group-yank-group]."
  (interactive "r")
  (let ((lines
         ;; Count lines.
         (save-excursion
           (count-lines
            (progn
              (goto-char begin)
              (beginning-of-line)
              (point))
            (progn
              (goto-char end)
              (beginning-of-line)
              (point))))))
    (goto-char begin)
    (beginning-of-line)                 ;Important when LINES < 1
    (gnus-group-kill-group lines)))

(defun gnus-group-kill-group (&optional n discard)
  "Kill the next N groups.
The killed newsgroups can be yanked by using \\[gnus-group-yank-group].
However, only groups that were alive can be yanked; already killed
groups or zombie groups can't be yanked.
The return value is the name of the group that was killed, or a list
of groups killed."
  (interactive "P")
  (let ((buffer-read-only nil)
        (groups (gnus-group-process-prefix n))
        group entry level out)
    (if (< (length groups) 10)
        ;; This is faster when there are few groups.
        (while groups
          (push (setq group (pop groups)) out)
          (gnus-group-remove-mark group)
          (setq level (gnus-group-group-level))
          (gnus-delete-line)
          (when (and (not discard)
                     (setq entry (gnus-gethash group gnus-newsrc-hashtb)))
            (gnus-undo-register
              `(progn
                (gnus-group-goto-group ,(gnus-group-group-name))
                (gnus-group-yank-group)))
            (push (cons (car entry) (nth 2 entry))
                  gnus-list-of-killed-groups))
          (gnus-group-change-level
           (if entry entry group) gnus-level-killed (if entry nil level)))
      ;; If there are lots and lots of groups to be killed, we use
      ;; this thing instead.
      (let (entry)
        (setq groups (nreverse groups))
        (while groups
          (gnus-group-remove-mark (setq group (pop groups)))
          (gnus-delete-line)
          (push group gnus-killed-list)
          (setq gnus-newsrc-alist
                (delq (assoc group gnus-newsrc-alist)
                      gnus-newsrc-alist))
          (when gnus-group-change-level-function
            (funcall gnus-group-change-level-function group 9 3))
          (cond
           ((setq entry (gnus-gethash group gnus-newsrc-hashtb))
            (push (cons (car entry) (nth 2 entry))
                  gnus-list-of-killed-groups)
            (setcdr (cdr entry) (cdddr entry)))
           ((member group gnus-zombie-list)
            (setq gnus-zombie-list (delete group gnus-zombie-list)))))
        (gnus-make-hashtable-from-newsrc-alist)))

    (gnus-group-position-point)
    (if (< (length out) 2) (car out) (nreverse out))))

(defun gnus-group-yank-group (&optional arg)
  "Yank the last newsgroups killed with \\[gnus-group-kill-group],
inserting it before the current newsgroup.  The numeric ARG specifies
how many newsgroups are to be yanked.  The name of the newsgroup yanked
is returned, or (if several groups are yanked) a list of yanked groups
is returned."
  (interactive "p")
  (setq arg (or arg 1))
  (let (info group prev out)
    (while (>= (decf arg) 0)
      (if (not (setq info (pop gnus-list-of-killed-groups)))
          (error "No more newsgroups to yank"))
      (push (setq group (nth 1 info)) out)
      ;; Find which newsgroup to insert this one before - search
      ;; backward until something suitable is found.  If there are no
      ;; other newsgroups in this buffer, just make this newsgroup the
      ;; first newsgroup.
      (setq prev (gnus-group-group-name))
      (gnus-group-change-level
       info (gnus-info-level (cdr info)) gnus-level-killed
       (and prev (gnus-gethash prev gnus-newsrc-hashtb))
       t)
      (gnus-group-insert-group-line-info group)
      (gnus-undo-register
        `(when (gnus-group-goto-group ,group)
          (gnus-group-kill-group 1))))
    (forward-line -1)
    (gnus-group-position-point)
    (if (< (length out) 2) (car out) (nreverse out))))

(defun gnus-group-kill-level (level)
  "Kill all groups that is on a certain LEVEL."
  (interactive "nKill all groups on level: ")
  (cond
   ((= level gnus-level-zombie)
    (setq gnus-killed-list
          (nconc gnus-zombie-list gnus-killed-list))
    (setq gnus-zombie-list nil))
   ((and (< level gnus-level-zombie)
         (> level 0)
         (or gnus-expert-user
             (gnus-yes-or-no-p
              (format
               "Do you really want to kill all groups on level %d? "
               level))))
    (let* ((prev gnus-newsrc-alist)
           (alist (cdr prev)))
      (while alist
        (if (= (gnus-info-level (car alist)) level)
            (progn
              (push (gnus-info-group (car alist)) gnus-killed-list)
              (setcdr prev (cdr alist)))
          (setq prev alist))
        (setq alist (cdr alist)))
      (gnus-make-hashtable-from-newsrc-alist)
      (gnus-group-list-groups)))
   (t
    (error "Can't kill; illegal level: %d" level))))

(defun gnus-group-list-all-groups (&optional arg)
  "List all newsgroups with level ARG or lower.
Default is gnus-level-unsubscribed, which lists all subscribed and most
unsubscribed groups."
  (interactive "P")
  (gnus-group-list-groups (or arg gnus-level-unsubscribed) t))

;; Redefine this to list ALL killed groups if prefix arg used.
;; Rewritten by engstrom@src.honeywell.com (Eric Engstrom).
(defun gnus-group-list-killed (&optional arg)
  "List all killed newsgroups in the group buffer.
If ARG is non-nil, list ALL killed groups known to Gnus.  This may
entail asking the server for the groups."
  (interactive "P")
  ;; Find all possible killed newsgroups if arg.
  (when arg
    (gnus-get-killed-groups))
  (if (not gnus-killed-list)
      (gnus-message 6 "No killed groups")
    (let (gnus-group-list-mode)
      (funcall gnus-group-prepare-function
               gnus-level-killed t gnus-level-killed))
    (goto-char (point-min)))
  (gnus-group-position-point))

(defun gnus-group-list-zombies ()
  "List all zombie newsgroups in the group buffer."
  (interactive)
  (if (not gnus-zombie-list)
      (gnus-message 6 "No zombie groups")
    (let (gnus-group-list-mode)
      (funcall gnus-group-prepare-function
               gnus-level-zombie t gnus-level-zombie))
    (goto-char (point-min)))
  (gnus-group-position-point))

(defun gnus-group-list-active ()
  "List all groups that are available from the server(s)."
  (interactive)
  ;; First we make sure that we have really read the active file.
  (unless (gnus-read-active-file-p)
    (let ((gnus-read-active-file t))
      (gnus-read-active-file)))
  ;; Find all groups and sort them.
  (let ((groups
         (sort
          (let (list)
            (mapatoms
             (lambda (sym)
               (and (boundp sym)
                    (symbol-value sym)
                    (setq list (cons (symbol-name sym) list))))
             gnus-active-hashtb)
            list)
          'string<))
        (buffer-read-only nil))
    (erase-buffer)
    (while groups
      (gnus-group-insert-group-line-info (pop groups)))
    (goto-char (point-min))))

(defun gnus-activate-all-groups (level)
  "Activate absolutely all groups."
  (interactive (list 7))
  (let ((gnus-activate-level level)
        (gnus-activate-foreign-newsgroups level))
    (gnus-group-get-new-news)))

(defun gnus-group-get-new-news (&optional arg)
  "Get newly arrived articles.
If ARG is a number, it specifies which levels you are interested in
re-scanning.  If ARG is non-nil and not a number, this will force
\"hard\" re-reading of the active files from all servers."
  (interactive "P")
  (save-excursion
    (set-buffer gnus-group-buffer)
    (run-hooks 'gnus-get-new-news-hook)
    ;; We might read in new NoCeM messages here.
    (when (and gnus-use-nocem 
               (null arg))
      (gnus-nocem-scan-groups))
    ;; If ARG is not a number, then we read the active file.
    (when (and arg (not (numberp arg)))
      (let ((gnus-read-active-file t))
        (gnus-read-active-file))
      (setq arg nil))

    (setq arg (gnus-group-default-level arg t))
    (if (and gnus-read-active-file (not arg))
        (progn
          (gnus-read-active-file)
          (gnus-get-unread-articles arg))
      (let ((gnus-read-active-file (if arg nil gnus-read-active-file)))
        (gnus-get-unread-articles arg)))
    (run-hooks 'gnus-after-getting-new-news-hook)
    (gnus-group-list-groups)))

(defun gnus-group-get-new-news-this-group (&optional n)
  "Check for newly arrived news in the current group (and the N-1 next groups).
The difference between N and the number of newsgroup checked is returned.
If N is negative, this group and the N-1 previous groups will be checked."
  (interactive "P")
  (let* ((groups (gnus-group-process-prefix n))
         (ret (if (numberp n) (- n (length groups)) 0))
         (beg (unless n (point)))
         group)
    (while (setq group (pop groups))
      (gnus-group-remove-mark group)
      (if (gnus-activate-group group 'scan)
          (progn
            (gnus-get-unread-articles-in-group
             (gnus-get-info group) (gnus-active group) t)
            (unless (gnus-virtual-group-p group)
              (gnus-close-group group))
            (gnus-group-update-group group))
        (if (eq (gnus-server-status (gnus-find-method-for-group group))
                'denied)
            (gnus-error "Server denied access")
          (gnus-error 3 "%s error: %s" group (gnus-status-message group)))))
    (when beg (goto-char beg))
    (when gnus-goto-next-group-when-activating
      (gnus-group-next-unread-group 1 t))
    (gnus-summary-position-point)
    ret))

(defun gnus-group-fetch-faq (group &optional faq-dir)
  "Fetch the FAQ for the current group."
  (interactive
   (list
    (and (gnus-group-group-name)
         (gnus-group-real-name (gnus-group-group-name)))
    (cond (current-prefix-arg
           (completing-read
            "Faq dir: " (and (listp gnus-group-faq-directory)
                             (mapcar (lambda (file) (list file))
                                     gnus-group-faq-directory)))))))
  (or faq-dir
      (setq faq-dir (if (listp gnus-group-faq-directory)
                        (car gnus-group-faq-directory)
                      gnus-group-faq-directory)))
  (or group (error "No group name given"))
  (let ((file (concat (file-name-as-directory faq-dir)
                      (gnus-group-real-name group))))
    (if (not (file-exists-p file))
        (error "No such file: %s" file)
      (find-file file))))

(defun gnus-group-describe-group (force &optional group)
  "Display a description of the current newsgroup."
  (interactive (list current-prefix-arg (gnus-group-group-name)))
  (let* ((method (gnus-find-method-for-group group))
         (mname (gnus-group-prefixed-name "" method))
         desc)
    (when (and force
               gnus-description-hashtb)
      (gnus-sethash mname nil gnus-description-hashtb))
    (or group (error "No group name given"))
    (and (or (and gnus-description-hashtb
                  ;; We check whether this group's method has been
                  ;; queried for a description file.
                  (gnus-gethash mname gnus-description-hashtb))
             (setq desc (gnus-group-get-description group))
             (gnus-read-descriptions-file method))
         (gnus-message 1
          (or desc (gnus-gethash group gnus-description-hashtb)
              "No description available")))))

;; Suggested by Per Abrahamsen <amanda@iesd.auc.dk>.
(defun gnus-group-describe-all-groups (&optional force)
  "Pop up a buffer with descriptions of all newsgroups."
  (interactive "P")
  (and force (setq gnus-description-hashtb nil))
  (if (not (or gnus-description-hashtb
               (gnus-read-all-descriptions-files)))
      (error "Couldn't request descriptions file"))
  (let ((buffer-read-only nil)
        b)
    (erase-buffer)
    (mapatoms
     (lambda (group)
       (setq b (point))
       (insert (format "      *: %-20s %s\n" (symbol-name group)
                       (symbol-value group)))
       (gnus-add-text-properties
        b (1+ b) (list 'gnus-group group
                       'gnus-unread t 'gnus-marked nil
                       'gnus-level (1+ gnus-level-subscribed))))
     gnus-description-hashtb)
    (goto-char (point-min))
    (gnus-group-position-point)))

;; Suggested by Daniel Quinlan <quinlan@best.com>.
(defun gnus-group-apropos (regexp &optional search-description)
  "List all newsgroups that have names that match a regexp."
  (interactive "sGnus apropos (regexp): ")
  (let ((prev "")
        (obuf (current-buffer))
        groups des)
    ;; Go through all newsgroups that are known to Gnus.
    (mapatoms
     (lambda (group)
       (and (symbol-name group)
            (string-match regexp (symbol-name group))
            (setq groups (cons (symbol-name group) groups))))
     gnus-active-hashtb)
    ;; Also go through all descriptions that are known to Gnus.
    (when search-description
      (mapatoms
       (lambda (group)
         (and (string-match regexp (symbol-value group))
              (gnus-active (symbol-name group))
              (setq groups (cons (symbol-name group) groups))))
       gnus-description-hashtb))
    (if (not groups)
        (gnus-message 3 "No groups matched \"%s\"." regexp)
      ;; Print out all the groups.
      (save-excursion
        (pop-to-buffer "*Gnus Help*")
        (buffer-disable-undo (current-buffer))
        (erase-buffer)
        (setq groups (sort groups 'string<))
        (while groups
          ;; Groups may be entered twice into the list of groups.
          (if (not (string= (car groups) prev))
              (progn
                (insert (setq prev (car groups)) "\n")
                (if (and gnus-description-hashtb
                         (setq des (gnus-gethash (car groups)
                                                 gnus-description-hashtb)))
                    (insert "  " des "\n"))))
          (setq groups (cdr groups)))
        (goto-char (point-min))))
    (pop-to-buffer obuf)))

(defun gnus-group-description-apropos (regexp)
  "List all newsgroups that have names or descriptions that match a regexp."
  (interactive "sGnus description apropos (regexp): ")
  (if (not (or gnus-description-hashtb
               (gnus-read-all-descriptions-files)))
      (error "Couldn't request descriptions file"))
  (gnus-group-apropos regexp t))

;; Suggested by Per Abrahamsen <amanda@iesd.auc.dk>.
(defun gnus-group-list-matching (level regexp &optional all lowest)
  "List all groups with unread articles that match REGEXP.
If the prefix LEVEL is non-nil, it should be a number that says which
level to cut off listing groups.
If ALL, also list groups with no unread articles.
If LOWEST, don't list groups with level lower than LOWEST.

This command may read the active file."
  (interactive "P\nsList newsgroups matching: ")
  ;; First make sure active file has been read.
  (when (and level
             (> (prefix-numeric-value level) gnus-level-killed))
    (gnus-get-killed-groups))
  (gnus-group-prepare-flat (or level gnus-level-subscribed)
                           all (or lowest 1) regexp)
  (goto-char (point-min))
  (gnus-group-position-point))

(defun gnus-group-list-all-matching (level regexp &optional lowest)
  "List all groups that match REGEXP.
If the prefix LEVEL is non-nil, it should be a number that says which
level to cut off listing groups.
If LOWEST, don't list groups with level lower than LOWEST."
  (interactive "P\nsList newsgroups matching: ")
  (gnus-group-list-matching (or level gnus-level-killed) regexp t lowest))

;; Suggested by Jack Vinson <vinson@unagi.cis.upenn.edu>.
(defun gnus-group-save-newsrc (&optional force)
  "Save the Gnus startup files.
If FORCE, force saving whether it is necessary or not."
  (interactive "P")
  (gnus-save-newsrc-file force))

(defun gnus-group-restart (&optional arg)
  "Force Gnus to read the .newsrc file."
  (interactive "P")
  (when (gnus-yes-or-no-p
         (format "Are you sure you want to read %s? "
                 gnus-current-startup-file))
    (gnus-save-newsrc-file)
    (gnus-setup-news 'force)
    (gnus-group-list-groups arg)))

(defun gnus-group-read-init-file ()
  "Read the Gnus elisp init file."
  (interactive)
  (gnus-read-init-file))

(defun gnus-group-check-bogus-groups (&optional silent)
  "Check bogus newsgroups.
If given a prefix, don't ask for confirmation before removing a bogus
group."
  (interactive "P")
  (gnus-check-bogus-newsgroups (and (not silent) (not gnus-expert-user)))
  (gnus-group-list-groups))

(defun gnus-group-edit-global-kill (&optional article group)
  "Edit the global kill file.
If GROUP, edit that local kill file instead."
  (interactive "P")
  (setq gnus-current-kill-article article)
  (gnus-kill-file-edit-file group)
  (gnus-message
   6
   (substitute-command-keys
    (format "Editing a %s kill file (Type \\[gnus-kill-file-exit] to exit)"
            (if group "local" "global")))))

(defun gnus-group-edit-local-kill (article group)
  "Edit a local kill file."
  (interactive (list nil (gnus-group-group-name)))
  (gnus-group-edit-global-kill article group))

(defun gnus-group-force-update ()
  "Update `.newsrc' file."
  (interactive)
  (gnus-save-newsrc-file))

(defun gnus-group-suspend ()
  "Suspend the current Gnus session.
In fact, cleanup buffers except for group mode buffer.
The hook gnus-suspend-gnus-hook is called before actually suspending."
  (interactive)
  (run-hooks 'gnus-suspend-gnus-hook)
  ;; Kill Gnus buffers except for group mode buffer.
  (let* ((group-buf (get-buffer gnus-group-buffer))
         ;; Do this on a separate list in case the user does a ^G before we finish
         (gnus-buffer-list
          (delete group-buf (delete gnus-dribble-buffer
                                    (append gnus-buffer-list nil)))))
    (while gnus-buffer-list
      (gnus-kill-buffer (pop gnus-buffer-list)))
    (gnus-kill-gnus-frames)
    (when group-buf
      (setq gnus-buffer-list (list group-buf))
      (bury-buffer group-buf)
      (delete-windows-on group-buf t))))

(defun gnus-group-clear-dribble ()
  "Clear all information from the dribble buffer."
  (interactive)
  (gnus-dribble-clear)
  (gnus-message 7 "Cleared dribble buffer"))

(defun gnus-group-exit ()
  "Quit reading news after updating .newsrc.eld and .newsrc.
The hook `gnus-exit-gnus-hook' is called before actually exiting."
  (interactive)
  (when 
      (or noninteractive                ;For gnus-batch-kill
          (not gnus-interactive-exit)   ;Without confirmation
          gnus-expert-user
          (gnus-y-or-n-p "Are you sure you want to quit reading news? "))
    (run-hooks 'gnus-exit-gnus-hook)
    ;; Offer to save data from non-quitted summary buffers.
    (gnus-offer-save-summaries)
    ;; Save the newsrc file(s).
    (gnus-save-newsrc-file)
    ;; Kill-em-all.
    (gnus-close-backends)
    ;; Reset everything.
    (gnus-clear-system)
    ;; Allow the user to do things after cleaning up.
    (run-hooks 'gnus-after-exiting-gnus-hook)))

(defun gnus-group-quit ()
  "Quit reading news without updating .newsrc.eld or .newsrc.
The hook `gnus-exit-gnus-hook' is called before actually exiting."
  (interactive)
  (when (or noninteractive              ;For gnus-batch-kill
            (zerop (buffer-size))
            (not (gnus-server-opened gnus-select-method))
            gnus-expert-user
            (not gnus-current-startup-file)
            (gnus-yes-or-no-p
             (format "Quit reading news without saving %s? "
                     (file-name-nondirectory gnus-current-startup-file))))
    (run-hooks 'gnus-exit-gnus-hook)
    (gnus-configure-windows 'group t)
    (gnus-dribble-save)
    (gnus-close-backends)
    (gnus-clear-system)
    (gnus-kill-buffer gnus-group-buffer)
    ;; Allow the user to do things after cleaning up.
    (run-hooks 'gnus-after-exiting-gnus-hook)))

(defun gnus-group-describe-briefly ()
  "Give a one line description of the group mode commands."
  (interactive)
  (gnus-message 7 (substitute-command-keys "\\<gnus-group-mode-map>\\[gnus-group-read-group]:Select  \\[gnus-group-next-unread-group]:Forward  \\[gnus-group-prev-unread-group]:Backward  \\[gnus-group-exit]:Exit  \\[gnus-info-find-node]:Run Info  \\[gnus-group-describe-briefly]:This help")))

(defun gnus-group-browse-foreign-server (method)
  "Browse a foreign news server.
If called interactively, this function will ask for a select method
 (nntp, nnspool, etc.) and a server address (eg. nntp.some.where).
If not, METHOD should be a list where the first element is the method
and the second element is the address."
  (interactive
   (list (let ((how (completing-read
                     "Which backend: "
                     (append gnus-valid-select-methods gnus-server-alist)
                     nil t (cons "nntp" 0) 'gnus-method-history)))
           ;; We either got a backend name or a virtual server name.
           ;; If the first, we also need an address.
           (if (assoc how gnus-valid-select-methods)
               (list (intern how)
                     ;; Suggested by mapjph@bath.ac.uk.
                     (completing-read
                      "Address: "
                      (mapcar (lambda (server) (list server))
                              gnus-secondary-servers)))
             ;; We got a server name, so we find the method.
             (gnus-server-to-method how)))))
  (gnus-browse-foreign-server method))

(defun gnus-group-set-info (info &optional method-only-group part)
  (let* ((entry (gnus-gethash
                 (or method-only-group (gnus-info-group info))
                 gnus-newsrc-hashtb))
         (part-info info)
         (info (if method-only-group (nth 2 entry) info))
         method)
    (when method-only-group
      (unless entry
        (error "Trying to change non-existent group %s" method-only-group))
      ;; We have received parts of the actual group info - either the
      ;; select method or the group parameters.  We first check
      ;; whether we have to extend the info, and if so, do that.
      (let ((len (length info))
            (total (if (eq part 'method) 5 6)))
        (when (< len total)
          (setcdr (nthcdr (1- len) info)
                  (make-list (- total len) nil)))
        ;; Then we enter the new info.
        (setcar (nthcdr (1- total) info) part-info)))
    (unless entry
      ;; This is a new group, so we just create it.
      (save-excursion
        (set-buffer gnus-group-buffer)
        (setq method (gnus-info-method info))
        (when (gnus-server-equal method "native")
          (setq method nil))
        (save-excursion
          (set-buffer gnus-group-buffer)
          (if method
              ;; It's a foreign group...
              (gnus-group-make-group
               (gnus-group-real-name (gnus-info-group info))
               (if (stringp method) method
                 (prin1-to-string (car method)))
               (and (consp method)
                    (nth 1 (gnus-info-method info))))
            ;; It's a native group.
            (gnus-group-make-group (gnus-info-group info))))
        (gnus-message 6 "Note: New group created")
        (setq entry
              (gnus-gethash (gnus-group-prefixed-name
                             (gnus-group-real-name (gnus-info-group info))
                             (or (gnus-info-method info) gnus-select-method))
                            gnus-newsrc-hashtb))))
    ;; Whether it was a new group or not, we now have the entry, so we
    ;; can do the update.
    (if entry
        (progn
          (setcar (nthcdr 2 entry) info)
          (when (and (not (eq (car entry) t))
                     (gnus-active (gnus-info-group info)))
            (setcar entry (length (gnus-list-of-unread-articles (car info))))))
      (error "No such group: %s" (gnus-info-group info)))))

(defun gnus-group-set-method-info (group select-method)
  (gnus-group-set-info select-method group 'method))

(defun gnus-group-set-params-info (group params)
  (gnus-group-set-info params group 'params))

(defun gnus-add-marked-articles (group type articles &optional info force)
  ;; Add ARTICLES of TYPE to the info of GROUP.
  ;; If INFO is non-nil, use that info.  If FORCE is non-nil, don't
  ;; add, but replace marked articles of TYPE with ARTICLES.
  (let ((info (or info (gnus-get-info group)))
        (uncompressed '(score bookmark killed))
        marked m)
    (or (not info)
        (and (not (setq marked (nthcdr 3 info)))
             (or (null articles)
                 (setcdr (nthcdr 2 info)
                         (list (list (cons type (gnus-compress-sequence
                                                 articles t)))))))
        (and (not (setq m (assq type (car marked))))
             (or (null articles)
                 (setcar marked
                         (cons (cons type (gnus-compress-sequence articles t) )
                               (car marked)))))
        (if force
            (if (null articles)
                (setcar (nthcdr 3 info)
                        (delq (assq type (car marked)) (car marked)))
              (setcdr m (gnus-compress-sequence articles t)))
          (setcdr m (gnus-compress-sequence
                     (sort (nconc (gnus-uncompress-range (cdr m))
                                  (copy-sequence articles)) '<) t))))))

(defun gnus-update-read-articles (group unread)
  "Update the list of read articles in GROUP."
  (let* ((active (or gnus-newsgroup-active (gnus-active group)))
         (entry (gnus-gethash group gnus-newsrc-hashtb))
         (info (nth 2 entry))
         (prev 1)
         (unread (sort (copy-sequence unread) '<))
         read)
    (if (or (not info) (not active))
        ;; There is no info on this group if it was, in fact,
        ;; killed.  Gnus stores no information on killed groups, so
        ;; there's nothing to be done.
        ;; One could store the information somewhere temporarily,
        ;; perhaps...  Hmmm...
        ()
      ;; Remove any negative articles numbers.
      (while (and unread (< (car unread) 0))
        (setq unread (cdr unread)))
      ;; Remove any expired article numbers
      (while (and unread (< (car unread) (car active)))
        (setq unread (cdr unread)))
      ;; Compute the ranges of read articles by looking at the list of
      ;; unread articles.
      (while unread
        (if (/= (car unread) prev)
            (setq read (cons (if (= prev (1- (car unread))) prev
                               (cons prev (1- (car unread)))) read)))
        (setq prev (1+ (car unread)))
        (setq unread (cdr unread)))
      (when (<= prev (cdr active))
        (setq read (cons (cons prev (cdr active)) read)))
      (gnus-undo-register
        `(progn
           (gnus-info-set-marks ,info ,(gnus-info-marks info))
           (gnus-info-set-read ,info ,(gnus-info-read info))
           (gnus-get-unread-articles-in-group ,info (gnus-active ,group))))
      ;; Enter this list into the group info.
      (gnus-info-set-read
       info (if (> (length read) 1) (nreverse read) read))
      ;; Set the number of unread articles in gnus-newsrc-hashtb.
      (gnus-get-unread-articles-in-group info (gnus-active group))
      t)))

(provide 'gnus-group)

;;; gnus-group.el ends here