[gnus] / lisp / gnus-sum.el

;;; gnus-sum.el --- summary mode commands for Gnus

;; Copyright (C) 1996-2012 Free Software Foundation, Inc.

;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
;; 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 3 of the License, 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.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;;; Code:

;; For Emacs <22.2 and XEmacs.
(eval-and-compile
  (unless (fboundp 'declare-function) (defmacro declare-function (&rest r))))
(eval-when-compile
  (require 'cl))
(eval-when-compile
  (when (featurep 'xemacs)
    (require 'easy-mmode))) ; for `define-minor-mode'

(defvar tool-bar-mode)
(defvar gnus-tmp-header)

(require 'gnus)
(require 'gnus-group)
(require 'gnus-spec)
(require 'gnus-range)
(require 'gnus-int)
(require 'gnus-undo)
(require 'gnus-util)
(require 'gmm-utils)
(require 'mm-decode)
(require 'nnoo)

(autoload 'gnus-summary-limit-include-cached "gnus-cache" nil t)
(autoload 'gnus-cache-write-active "gnus-cache")
(autoload 'gnus-mailing-list-insinuate "gnus-ml" nil t)
(autoload 'turn-on-gnus-mailing-list-mode "gnus-ml" nil t)
(autoload 'gnus-pick-line-number "gnus-salt" nil t)
(autoload 'mm-uu-dissect "mm-uu")
(autoload 'gnus-article-outlook-deuglify-article "deuglify"
  "Deuglify broken Outlook (Express) articles and redisplay."
  t)
(autoload 'gnus-article-outlook-unwrap-lines "deuglify" nil t)
(autoload 'gnus-article-outlook-repair-attribution "deuglify" nil t)
(autoload 'gnus-article-outlook-rearrange-citation "deuglify" nil t)
(autoload 'nnir-article-rsv "nnir" nil nil 'macro)
(autoload 'nnir-article-group "nnir" nil nil 'macro)

(defcustom gnus-kill-summary-on-exit t
  "*If non-nil, kill the summary buffer when you exit from it.
If nil, the summary will become a \"*Dead Summary*\" buffer, and
it will be killed sometime later."
  :group 'gnus-summary-exit
  :type 'boolean)

(defcustom gnus-summary-next-group-on-exit t
  "If non-nil, go to the next unread newsgroup on summary exit.
See `gnus-group-goto-unread'."
  :link '(custom-manual "(gnus)Group Maneuvering")
  :group 'gnus-summary-exit
  :version "23.1" ;; No Gnus
  :type 'boolean)

(defcustom gnus-summary-stop-at-end-of-message nil
  "If non-nil, don't select the next message when using `SPC'."
  :link '(custom-manual "(gnus)Group Maneuvering")
  :group 'gnus-summary-maneuvering
  :version "24.1"
  :type 'boolean)

(defcustom gnus-fetch-old-headers nil
  "*Non-nil means that Gnus will try to build threads by grabbing old headers.
If an unread article in the group refers to an older, already
read (or just marked as read) article, the old article will not
normally be displayed in the Summary buffer.  If this variable is
t, Gnus will attempt to grab the headers to the old articles, and
thereby build complete threads.  If it has the value `some', all
old headers will be fetched but only enough headers to connect
otherwise loose threads will be displayed.  This variable can
also be a number.  In that case, no more than that number of old
headers will be fetched.  If it has the value `invisible', all
old headers will be fetched, but none will be displayed.

The server has to support NOV for any of this to work.

This feature can seriously impact performance it ignores all
locally cached header entries.  Setting it to t for groups for a
server that doesn't expire articles (such as news.gmane.org),
leads to very slow summary generation."
  :group 'gnus-thread
  :type '(choice (const :tag "off" nil)
                 (const :tag "on" t)
                 (const some)
                 (const invisible)
                 number
                 (sexp :menu-tag "other" t)))

(defcustom gnus-refer-thread-limit 500
  "*The number of old headers to fetch when doing \\<gnus-summary-mode-map>\\[gnus-summary-refer-thread].
If t, fetch all the available old headers."
  :group 'gnus-thread
  :type '(choice number
                 (sexp :menu-tag "other" t)))

(defcustom gnus-refer-thread-use-nnir nil
  "*Use nnir to search an entire server when referring threads. A
nil value will only search for thread-related articles in the
current group."
  :group 'gnus-thread
  :type 'boolean)

(defcustom gnus-summary-make-false-root 'adopt
  "*nil means that Gnus won't gather loose threads.
If the root of a thread has expired or been read in a previous
session, the information necessary to build a complete thread has been
lost.  Instead of having many small sub-threads from this original thread
scattered all over the summary buffer, Gnus can gather them.

If non-nil, Gnus will try to gather all loose sub-threads from an
original thread into one large thread.

If this variable is non-nil, it should be one of `none', `adopt',
`dummy' or `empty'.

If this variable is `none', Gnus will not make a false root, but just
present the sub-threads after another.
If this variable is `dummy', Gnus will create a dummy root that will
have all the sub-threads as children.
If this variable is `adopt', Gnus will make one of the \"children\"
the parent and mark all the step-children as such.
If this variable is `empty', the \"children\" are printed with empty
subject fields.  (Or rather, they will be printed with a string
given by the `gnus-summary-same-subject' variable.)"
  :group 'gnus-thread
  :type '(choice (const :tag "off" nil)
                 (const none)
                 (const dummy)
                 (const adopt)
                 (const empty)))

(defcustom gnus-summary-make-false-root-always nil
  "Always make a false dummy root."
  :version "22.1"
  :group 'gnus-thread
  :type 'boolean)

(defcustom gnus-summary-gather-exclude-subject "^ *$\\|^(none)$"
  "*A regexp to match subjects to be excluded from loose thread gathering.
As loose thread gathering is done on subjects only, that means that
there can be many false gatherings performed.  By rooting out certain
common subjects, gathering might become saner."
  :group 'gnus-thread
  :type 'regexp)

(defcustom gnus-summary-gather-subject-limit nil
  "*Maximum length of subject comparisons when gathering loose threads.
Use nil to compare full subjects.  Setting this variable to a low
number will help gather threads that have been corrupted by
newsreaders chopping off subject lines, but it might also mean that
unrelated articles that have subject that happen to begin with the
same few characters will be incorrectly gathered.

If this variable is `fuzzy', Gnus will use a fuzzy algorithm when
comparing subjects."
  :group 'gnus-thread
  :type '(choice (const :tag "off" nil)
                 (const fuzzy)
                 (sexp :menu-tag "on" t)))

(defcustom gnus-simplify-subject-functions nil
  "List of functions taking a string argument that simplify subjects.
The functions are applied recursively.

Useful functions to put in this list include:
`gnus-simplify-subject-re', `gnus-simplify-subject-fuzzy',
`gnus-simplify-whitespace', and `gnus-simplify-all-whitespace'."
  :group 'gnus-thread
  :type '(repeat function))

(defcustom gnus-simplify-ignored-prefixes nil
  "*Remove matches for this regexp from subject lines when simplifying fuzzily."
  :group 'gnus-thread
  :type '(choice (const :tag "off" nil)
                 regexp))

(defcustom gnus-build-sparse-threads nil
  "*If non-nil, fill in the gaps in threads.
If `some', only fill in the gaps that are needed to tie loose threads
together.  If `more', fill in all leaf nodes that Gnus can find.  If
non-nil and non-`some', fill in all gaps that Gnus manages to guess."
  :group 'gnus-thread
  :type '(choice (const :tag "off" nil)
                 (const some)
                 (const more)
                 (sexp :menu-tag "all" t)))

(defcustom gnus-summary-thread-gathering-function
  'gnus-gather-threads-by-subject
  "*Function used for gathering loose threads.
There are two pre-defined functions: `gnus-gather-threads-by-subject',
which only takes Subjects into consideration; and
`gnus-gather-threads-by-references', which compared the References
headers of the articles to find matches."
  :group 'gnus-thread
  :type '(radio (function-item gnus-gather-threads-by-subject)
                (function-item gnus-gather-threads-by-references)
                (function :tag "other")))

(defcustom gnus-summary-same-subject ""
  "*String indicating that the current article has the same subject as the previous.
This variable will only be used if the value of
`gnus-summary-make-false-root' is `empty'."
  :group 'gnus-summary-format
  :type 'string)

(defcustom gnus-summary-goto-unread nil
  "*If t, many commands will go to the next unread article.
This applies to marking commands as well as other commands that
\"naturally\" select the next article, like, for instance, `SPC' at
the end of an article.

If nil, the marking commands do NOT go to the next unread article
\(they go to the next article instead).  If `never', commands that
usually go to the next unread article, will go to the next article,
whether it is read or not."
  :version "24.1"
  :group 'gnus-summary-marks
  :link '(custom-manual "(gnus)Setting Marks")
  :type '(choice (const :tag "off" nil)
                 (const never)
                 (sexp :menu-tag "on" t)))

(defcustom gnus-summary-default-score 0
  "*Default article score level.
All scores generated by the score files will be added to this score.
If this variable is nil, scoring will be disabled."
  :group 'gnus-score-default
  :type '(choice (const :tag "disable")
                 integer))

(defcustom gnus-summary-default-high-score 0
  "*Default threshold for a high scored article.
An article will be highlighted as high scored if its score is greater
than this score."
  :version "22.1"
  :group 'gnus-score-default
  :type 'integer)

(defcustom gnus-summary-default-low-score 0
  "*Default threshold for a low scored article.
An article will be highlighted as low scored if its score is smaller
than this score."
  :version "22.1"
  :group 'gnus-score-default
  :type 'integer)

(defcustom gnus-summary-zcore-fuzz 0
  "*Fuzziness factor for the zcore in the summary buffer.
Articles with scores closer than this to `gnus-summary-default-score'
will not be marked."
  :group 'gnus-summary-format
  :type 'integer)

(defcustom gnus-simplify-subject-fuzzy-regexp nil
  "*Strings to be removed when doing fuzzy matches.
This can either be a regular expression or list of regular expressions
that will be removed from subject strings if fuzzy subject
simplification is selected."
  :group 'gnus-thread
  :type '(repeat regexp))

(defcustom gnus-show-threads t
  "*If non-nil, display threads in summary mode."
  :group 'gnus-thread
  :type 'boolean)

(defcustom gnus-thread-hide-subtree nil
  "*If non-nil, hide all threads initially.
This can be a predicate specifier which says which threads to hide.
If threads are hidden, you have to run the command
`gnus-summary-show-thread' by hand or select an article."
  :group 'gnus-thread
  :type '(radio (sexp :format "Non-nil\n"
                      :match (lambda (widget value)
                               (not (or (consp value) (functionp value))))
                      :value t)
                (const nil)
                (sexp :tag "Predicate specifier")))

(defcustom gnus-thread-hide-killed t
  "*If non-nil, hide killed threads automatically."
  :group 'gnus-thread
  :type 'boolean)

(defcustom gnus-thread-ignore-subject t
  "*If non-nil, which is the default, ignore subjects and do all threading based on the Reference header.
If nil, articles that have different subjects from their parents will
start separate threads."
  :group 'gnus-thread
  :type 'boolean)

(defcustom gnus-thread-operation-ignore-subject t
  "*If non-nil, subjects will be ignored when doing thread commands.
This affects commands like `gnus-summary-kill-thread' and
`gnus-summary-lower-thread'.

If this variable is nil, articles in the same thread with different
subjects will not be included in the operation in question.  If this
variable is `fuzzy', only articles that have subjects that are fuzzily
equal will be included."
  :group 'gnus-thread
  :type '(choice (const :tag "off" nil)
                 (const fuzzy)
                 (sexp :tag "on" t)))

(defcustom gnus-thread-indent-level 4
  "*Number that says how much each sub-thread should be indented."
  :group 'gnus-thread
  :type 'integer)

(defcustom gnus-auto-extend-newsgroup t
  "*If non-nil, extend newsgroup forward and backward when requested."
  :group 'gnus-summary-choose
  :type 'boolean)

(defcustom gnus-auto-select-first t
  "If non-nil, select an article on group entry.
An article is selected automatically when entering a group
e.g. with \\<gnus-group-mode-map>\\[gnus-group-read-group], or via `gnus-summary-next-page' or
`gnus-summary-catchup-and-goto-next-group'.

Which article is selected is controlled by the variable
`gnus-auto-select-subject'.

If you want to prevent automatic selection of articles in some
newsgroups, set the variable to nil in `gnus-select-group-hook'."
  ;; Commands include...
  ;; \\<gnus-group-mode-map>\\[gnus-group-read-group]
  ;; \\<gnus-summary-mode-map>\\[gnus-summary-next-page]
  ;; \\<gnus-summary-mode-map>\\[gnus-summary-catchup-and-goto-next-group]
  :group 'gnus-group-select
  :type '(choice (const :tag "none" nil)
                 (sexp :menu-tag "first" t)))

(defcustom gnus-auto-select-subject 'unseen-or-unread
  "*Says what subject to place under point when entering a group.

This variable can either be the symbols `first' (place point on the
first subject), `unread' (place point on the subject line of the first
unread article), `best' (place point on the subject line of the
highest-scored article), `unseen' (place point on the subject line of
the first unseen article), `unseen-or-unread' (place point on the subject
line of the first unseen article or, if all articles have been seen, on the
subject line of the first unread article), or a function to be called to
place point on some subject line."
  :version "24.1"
  :group 'gnus-group-select
  :type '(choice (const best)
                 (const unread)
                 (const first)
                 (const unseen)
                 (const unseen-or-unread)
                 (function :tag "Function to call")))

(defcustom gnus-auto-select-next t
  "*If non-nil, offer to go to the next group from the end of the previous.
If the value is t and the next newsgroup is empty, Gnus will exit
summary mode and go back to group mode.  If the value is neither nil
nor t, Gnus will select the following unread newsgroup.  In
particular, if the value is the symbol `quietly', the next unread
newsgroup will be selected without any confirmation, and if it is
`almost-quietly', the next group will be selected without any
confirmation if you are located on the last article in the group.
Finally, if this variable is `slightly-quietly', the `\\<gnus-summary-mode-map>\\[gnus-summary-catchup-and-goto-next-group]' command
will go to the next group without confirmation."
  :group 'gnus-summary-maneuvering
  :type '(choice (const :tag "off" nil)
                 (const quietly)
                 (const almost-quietly)
                 (const slightly-quietly)
                 (sexp :menu-tag "on" t)))

(defcustom gnus-auto-select-same nil
  "*If non-nil, select the next article with the same subject.
If there are no more articles with the same subject, go to
the first unread article."
  :group 'gnus-summary-maneuvering
  :type 'boolean)

(defcustom gnus-auto-select-on-ephemeral-exit 'next-noselect
  "What article should be selected after exiting an ephemeral group.
Valid values include:

`next'
  Select the next article.
`next-unread'
  Select the next unread article.
`next-noselect'
  Move the cursor to the next article.  This is the default.
`next-unread-noselect'
  Move the cursor to the next unread article.

If it has any other value or there is no next (unread) article, the
article selected before entering to the ephemeral group will appear."
  :version "23.1" ;; No Gnus
  :group 'gnus-summary-maneuvering
  :type '(choice :format "%{%t%}:\n %[Value Menu%] %v"
                 (const next) (const next-unread)
                 (const next-noselect) (const next-unread-noselect)
                 (sexp :tag "other" :value nil)))

(defcustom gnus-auto-goto-ignores 'unfetched
  "*Says how to handle unfetched articles when maneuvering.

This variable can either be the symbols nil (maneuver to any
article), `undownloaded' (maneuvering while unplugged ignores articles
that have not been fetched), `always-undownloaded' (maneuvering always
ignores articles that have not been fetched), `unfetched' (maneuvering
ignores articles whose headers have not been fetched).

NOTE: The list of unfetched articles will always be nil when plugged
and, when unplugged, a subset of the undownloaded article list."
  :version "22.1"
  :group 'gnus-summary-maneuvering
  :type '(choice (const :tag "None" nil)
                 (const :tag "Undownloaded when unplugged" undownloaded)
                 (const :tag "Undownloaded" always-undownloaded)
                 (const :tag "Unfetched" unfetched)))

(defcustom gnus-summary-check-current nil
  "*If non-nil, consider the current article when moving.
The \"unread\" movement commands will stay on the same line if the
current article is unread."
  :group 'gnus-summary-maneuvering
  :type 'boolean)

(defcustom gnus-auto-center-summary 2
  "*If non-nil, always center the current summary buffer.
In particular, if `vertical' do only vertical recentering.  If non-nil
and non-`vertical', do both horizontal and vertical recentering."
  :group 'gnus-summary-maneuvering
  :type '(choice (const :tag "none" nil)
                 (const vertical)
                 (integer :tag "height")
                 (sexp :menu-tag "both" t)))

(defcustom gnus-auto-center-group t
  "If non-nil, always center the group buffer."
  :group 'gnus-summary-maneuvering
  :type 'boolean)

(defcustom gnus-show-all-headers nil
  "*If non-nil, don't hide any headers."
  :group 'gnus-article-hiding
  :group 'gnus-article-headers
  :type 'boolean)

(defcustom gnus-summary-ignore-duplicates nil
  "*If non-nil, ignore articles with identical Message-ID headers."
  :group 'gnus-summary
  :type 'boolean)

(defcustom gnus-single-article-buffer nil
  "*If non-nil, display all articles in the same buffer.
If nil, each group will get its own article buffer."
  :version "24.1"
  :group 'gnus-article-various
  :type 'boolean)

(defcustom gnus-widen-article-window nil
  "If non-nil, selecting the article buffer will display only the article buffer."
  :version "24.1"
  :group 'gnus-article-various
  :type 'boolean)

(defcustom gnus-break-pages t
  "*If non-nil, do page breaking on articles.
The page delimiter is specified by the `gnus-page-delimiter'
variable."
  :group 'gnus-article-various
  :type 'boolean)

(defcustom gnus-move-split-methods nil
  "*Variable used to suggest where articles are to be moved to.
It uses the same syntax as the `gnus-split-methods' variable.
However, whereas `gnus-split-methods' specifies file names as targets,
this variable specifies group names."
  :group 'gnus-summary-mail
  :type '(repeat (choice (list :value (fun) function)
                         (cons :value ("" "") regexp (repeat string))
                         (sexp :value nil))))

(defcustom gnus-move-group-prefix-function 'gnus-group-real-prefix
  "Function used to compute default prefix for article move/copy/etc prompts.
The function should take one argument, a group name, and return a
string with the suggested prefix."
  :group 'gnus-summary-mail
  :type 'function)

;; FIXME: Although the custom type is `character' for the following variables,
;; using multibyte characters (Latin-1, UTF-8) doesn't work.  -- rs

(defcustom gnus-unread-mark ?           ;Whitespace
  "*Mark used for unread articles."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-ticked-mark ?!
  "*Mark used for ticked articles."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-dormant-mark ??
  "*Mark used for dormant articles."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-del-mark ?r
  "*Mark used for del'd articles."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-read-mark ?R
  "*Mark used for read articles."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-expirable-mark ?E
  "*Mark used for expirable articles."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-killed-mark ?K
  "*Mark used for killed articles."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-spam-mark ?$
  "*Mark used for spam articles."
  :version "22.1"
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-kill-file-mark ?X
  "*Mark used for articles killed by kill files."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-low-score-mark ?Y
  "*Mark used for articles with a low score."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-catchup-mark ?C
  "*Mark used for articles that are caught up."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-replied-mark ?A
  "*Mark used for articles that have been replied to."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-forwarded-mark ?F
  "*Mark used for articles that have been forwarded."
  :version "22.1"
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-recent-mark ?N
  "*Mark used for articles that are recent."
  :version "22.1"
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-cached-mark ?*
  "*Mark used for articles that are in the cache."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-saved-mark ?S
  "*Mark used for articles that have been saved."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-unseen-mark ?.
  "*Mark used for articles that haven't been seen."
  :version "22.1"
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-no-mark ?               ;Whitespace
  "*Mark used for articles that have no other secondary mark."
  :version "22.1"
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-ancient-mark ?O
  "*Mark used for ancient articles."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-sparse-mark ?Q
  "*Mark used for sparsely reffed articles."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-canceled-mark ?G
  "*Mark used for canceled articles."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-duplicate-mark ?M
  "*Mark used for duplicate articles."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-undownloaded-mark ?-
  "*Mark used for articles that weren't downloaded."
  :version "22.1"
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-downloaded-mark ?+
  "*Mark used for articles that were downloaded."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-downloadable-mark ?%
  "*Mark used for articles that are to be downloaded."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-unsendable-mark ?=
  "*Mark used for articles that won't be sent."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-score-over-mark ?+
  "*Score mark used for articles with high scores."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-score-below-mark ?-
  "*Score mark used for articles with low scores."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-empty-thread-mark ?     ;Whitespace
  "*There is no thread under the article."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-not-empty-thread-mark ?=
  "*There is a thread under the article."
  :group 'gnus-summary-marks
  :type 'character)

(defcustom gnus-view-pseudo-asynchronously nil
  "*If non-nil, Gnus will view pseudo-articles asynchronously."
  :group 'gnus-extract-view
  :type 'boolean)

(defcustom gnus-auto-expirable-marks
  (list gnus-killed-mark gnus-del-mark gnus-catchup-mark
        gnus-low-score-mark gnus-ancient-mark gnus-read-mark
        gnus-duplicate-mark)
  "*The list of marks converted into expiration if a group is auto-expirable."
  :version "24.1"
  :group 'gnus-summary
  :type '(repeat character))

(defcustom gnus-inhibit-user-auto-expire t
  "*If non-nil, user marking commands will not mark an article as expirable, even if the group has auto-expire turned on."
  :version "21.1"
  :group 'gnus-summary
  :type 'boolean)

(defcustom gnus-mark-copied-or-moved-articles-as-expirable nil
  "If non-nil, mark articles copied or moved to auto-expire group as expirable.
If nil, the expirable marks will be unchanged except that the marks
will be removed when copying or moving articles to a group that has
not turned auto-expire on.  If non-nil, articles that have been read
will be marked as expirable when being copied or moved to a group in
which auto-expire is turned on."
  :version "23.2"
  :type 'boolean
  :group 'gnus-summary-marks)

(defcustom gnus-view-pseudos nil
  "*If `automatic', pseudo-articles will be viewed automatically.
If `not-confirm', pseudos will be viewed automatically, and the user
will not be asked to confirm the command."
  :group 'gnus-extract-view
  :type '(choice (const :tag "off" nil)
                 (const automatic)
                 (const not-confirm)))

(defcustom gnus-view-pseudos-separately t
  "*If non-nil, one pseudo-article will be created for each file to be viewed.
If nil, all files that use the same viewing command will be given as a
list of parameters to that command."
  :group 'gnus-extract-view
  :type 'boolean)

(defcustom gnus-insert-pseudo-articles t
  "*If non-nil, insert pseudo-articles when decoding articles."
  :group 'gnus-extract-view
  :type 'boolean)

(defcustom gnus-summary-dummy-line-format
  "   %(:                             :%) %S\n"
  "*The format specification for the dummy roots in the summary buffer.
It works along the same lines as a normal formatting string,
with some simple extensions.

%S  The subject

General format specifiers can also be used.
See `(gnus)Formatting Variables'."
  :link '(custom-manual "(gnus)Formatting Variables")
  :group 'gnus-threading
  :type 'string)

(defcustom gnus-summary-mode-line-format "Gnus: %g [%A] %Z"
  "*The format specification for the summary mode line.
It works along the same lines as a normal formatting string,
with some simple extensions:

%G  Group name
%p  Unprefixed group name
%A  Current article number
%z  Current article score
%V  Gnus version
%U  Number of unread articles in the group
%e  Number of unselected articles in the group
%Z  A string with unread/unselected article counts
%g  Shortish group name
%S  Subject of the current article
%u  User-defined spec
%s  Current score file name
%d  Number of dormant articles
%r  Number of articles that have been marked as read in this session
%E  Number of articles expunged by the score files"
  :group 'gnus-summary-format
  :type 'string)

(defcustom gnus-list-identifiers nil
  "Regexp that matches list identifiers to be removed from subject.
This can also be a list of regexps."
  :version "21.1"
  :group 'gnus-summary-format
  :group 'gnus-article-hiding
  :type '(choice (const :tag "none" nil)
                 (regexp :value ".*")
                 (repeat :value (".*") regexp)))

(defcustom gnus-summary-mark-below 0
  "*Mark all articles with a score below this variable as read.
This variable is local to each summary buffer and usually set by the
score file."
  :group 'gnus-score-default
  :type 'integer)

(defun gnus-widget-reversible-match (widget value)
  "Ignoring WIDGET, convert VALUE to internal form.
VALUE should have the form `FOO' or `(not FOO)', where FOO is an symbol."
  ;; (debug value)
  (or (symbolp value)
      (and (listp value)
           (eq (length value) 2)
           (eq (nth 0 value) 'not)
           (symbolp (nth 1 value)))))

(defun gnus-widget-reversible-to-internal (widget value)
  "Ignoring WIDGET, convert VALUE to internal form.
VALUE should have the form `FOO' or `(not FOO)', where FOO is an atom.
FOO is converted to (FOO nil) and (not FOO) is converted to (FOO t)."
  ;; (debug value)
  (if (atom value)
      (list value nil)
    (list (nth 1 value) t)))

(defun gnus-widget-reversible-to-external (widget value)
  "Ignoring WIDGET, convert VALUE to external form.
VALUE should have the form `(FOO nil)' or `(FOO t)', where FOO is an atom.
\(FOO  nil) is converted to FOO and (FOO t) is converted to (not FOO)."
  ;; (debug value)
  (if (nth 1 value)
      (list 'not (nth 0 value))
    (nth 0 value)))

(define-widget 'gnus-widget-reversible 'group
  "A `group' that convert values."
  :match 'gnus-widget-reversible-match
  :value-to-internal 'gnus-widget-reversible-to-internal
  :value-to-external 'gnus-widget-reversible-to-external)

(defcustom gnus-article-sort-functions '(gnus-article-sort-by-number)
  "*List of functions used for sorting articles in the summary buffer.

Each function takes two articles and returns non-nil if the first
article should be sorted before the other.  If you use more than one
function, the primary sort function should be the last.  You should
probably always include `gnus-article-sort-by-number' in the list of
sorting functions -- preferably first.  Also note that sorting by date
is often much slower than sorting by number, and the sorting order is
very similar.  (Sorting by date means sorting by the time the message
was sent, sorting by number means sorting by arrival time.)

Each item can also be a list `(not F)' where F is a function;
this reverses the sort order.

Ready-made functions include `gnus-article-sort-by-number',
`gnus-article-sort-by-author', `gnus-article-sort-by-subject',
`gnus-article-sort-by-date', `gnus-article-sort-by-random'
and `gnus-article-sort-by-score'.

When threading is turned on, the variable `gnus-thread-sort-functions'
controls how articles are sorted."
  :group 'gnus-summary-sort
  :type '(repeat (gnus-widget-reversible
                  (choice (function-item gnus-article-sort-by-number)
                          (function-item gnus-article-sort-by-author)
                          (function-item gnus-article-sort-by-subject)
                          (function-item gnus-article-sort-by-date)
                          (function-item gnus-article-sort-by-score)
                          (function-item gnus-article-sort-by-random)
                          (function :tag "other"))
                  (boolean :tag "Reverse order"))))


(defcustom gnus-thread-sort-functions '(gnus-thread-sort-by-number)
  "*List of functions used for sorting threads in the summary buffer.
By default, threads are sorted by article number.

Each function takes two threads and returns non-nil if the first
thread should be sorted before the other.  If you use more than one
function, the primary sort function should be the last.  You should
probably always include `gnus-thread-sort-by-number' in the list of
sorting functions -- preferably first.  Also note that sorting by date
is often much slower than sorting by number, and the sorting order is
very similar.  (Sorting by date means sorting by the time the message
was sent, sorting by number means sorting by arrival time.)

Each list item can also be a list `(not F)' where F is a
function; this specifies reversed sort order.

Ready-made functions include `gnus-thread-sort-by-number',
`gnus-thread-sort-by-author', `gnus-thread-sort-by-recipient'
`gnus-thread-sort-by-subject', `gnus-thread-sort-by-date',
`gnus-thread-sort-by-score', `gnus-thread-sort-by-most-recent-number',
`gnus-thread-sort-by-most-recent-date', `gnus-thread-sort-by-random',
and `gnus-thread-sort-by-total-score' (see
`gnus-thread-score-function').

When threading is turned off, the variable
`gnus-article-sort-functions' controls how articles are sorted."
  :group 'gnus-summary-sort
  :type '(repeat
          (gnus-widget-reversible
           (choice (function-item gnus-thread-sort-by-number)
                   (function-item gnus-thread-sort-by-author)
                   (function-item gnus-thread-sort-by-recipient)
                   (function-item gnus-thread-sort-by-subject)
                   (function-item gnus-thread-sort-by-date)
                   (function-item gnus-thread-sort-by-score)
                   (function-item gnus-thread-sort-by-most-recent-number)
                   (function-item gnus-thread-sort-by-most-recent-date)
                   (function-item gnus-thread-sort-by-random)
                   (function-item gnus-thread-sort-by-total-score)
                   (function :tag "other"))
           (boolean :tag "Reverse order"))))

(defcustom gnus-thread-score-function '+
  "*Function used for calculating the total score of a thread.

The function is called with the scores of the article and each
subthread and should then return the score of the thread.

Some functions you can use are `+', `max', or `min'."
  :group 'gnus-summary-sort
  :type 'function)

(defcustom gnus-summary-expunge-below nil
  "All articles that have a score less than this variable will be expunged.
This variable is local to the summary buffers."
  :group 'gnus-score-default
  :type '(choice (const :tag "off" nil)
                 integer))

(defcustom gnus-thread-expunge-below nil
  "All threads that have a total score less than this variable will be expunged.
See `gnus-thread-score-function' for en explanation of what a
\"thread score\" is.

This variable is local to the summary buffers."
  :group 'gnus-threading
  :group 'gnus-score-default
  :type '(choice (const :tag "off" nil)
                 integer))

(defcustom gnus-summary-mode-hook nil
  "*A hook for Gnus summary mode.
This hook is run before any variables are set in the summary buffer."
  :options '(turn-on-gnus-mailing-list-mode gnus-pick-mode)
  :group 'gnus-summary-various
  :type 'hook)

;; Extracted from gnus-xmas-redefine in order to preserve user settings
(when (featurep 'xemacs)
  (add-hook 'gnus-summary-mode-hook 'gnus-xmas-summary-menu-add)
  (add-hook 'gnus-summary-mode-hook 'gnus-xmas-setup-summary-toolbar)
  (add-hook 'gnus-summary-mode-hook
            'gnus-xmas-switch-horizontal-scrollbar-off))

(defcustom gnus-summary-menu-hook nil
  "*Hook run after the creation of the summary mode menu."
  :group 'gnus-summary-visual
  :type 'hook)

(defcustom gnus-summary-exit-hook nil
  "*A hook called on exit from the summary buffer.
It will be called with point in the group buffer."
  :group 'gnus-summary-exit
  :type 'hook)

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

(defcustom gnus-summary-prepared-hook nil
  "*A hook called as the last thing after the summary buffer has been generated."
  :group 'gnus-summary-various
  :type 'hook)

(defcustom gnus-summary-generate-hook nil
  "*A hook run just before generating the summary buffer.
This hook is commonly used to customize threading variables and the
like."
  :group 'gnus-summary-various
  :type 'hook)

(defcustom gnus-select-group-hook nil
  "*A hook called when a newsgroup is selected.

If you'd like to simplify subjects like the
`gnus-summary-next-same-subject' command does, you can use the
following hook:

 (add-hook gnus-select-group-hook
           (lambda ()
             (mapcar (lambda (header)
                       (mail-header-set-subject
                        header
                        (gnus-simplify-subject
                         (mail-header-subject header) 're-only)))
                     gnus-newsgroup-headers)))"
  :group 'gnus-group-select
  :type 'hook)

(defcustom gnus-select-article-hook nil
  "*A hook called when an article is selected."
  :group 'gnus-summary-choose
  :options '(gnus-agent-fetch-selected-article)
  :type 'hook)

(defcustom gnus-visual-mark-article-hook
  (list 'gnus-highlight-selected-summary)
  "*Hook run after selecting an article in the summary buffer.
It is meant to be used for highlighting the article in some way.  It
is not run if `gnus-visual' is nil."
  :group 'gnus-summary-visual
  :type 'hook)

(defcustom gnus-parse-headers-hook nil
  "*A hook called before parsing the headers."
  :group 'gnus-various
  :type 'hook)

(defcustom gnus-exit-group-hook nil
  "*A hook called when exiting summary mode.
This hook is not called from the non-updating exit commands like `Q'."
  :group 'gnus-various
  :type 'hook)

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

The default function `gnus-summary-highlight-line' will
highlight the line according to the `gnus-summary-highlight'
variable."
  :group 'gnus-summary-visual
  :type 'hook)

(defcustom gnus-mark-article-hook '(gnus-summary-mark-read-and-unread-as-read)
  "*A hook called when an article is selected for the first time.
The hook is intended to mark an article as read (or unread)
automatically when it is selected."
  :group 'gnus-summary-choose
  :type 'hook)

(defcustom gnus-group-no-more-groups-hook nil
  "*A hook run when returning to group mode having no more (unread) groups."
  :group 'gnus-group-select
  :type 'hook)

(defcustom gnus-ps-print-hook nil
  "*A hook run before ps-printing something from Gnus."
  :group 'gnus-summary
  :type 'hook)

(defcustom gnus-summary-article-move-hook nil
  "*A hook called after an article is moved, copied, respooled, or crossposted."
  :version "22.1"
  :group 'gnus-summary
  :type 'hook)

(defcustom gnus-summary-article-delete-hook nil
  "*A hook called after an article is deleted."
  :version "22.1"
  :group 'gnus-summary
  :type 'hook)

(defcustom gnus-summary-article-expire-hook nil
  "*A hook called after an article is expired."
  :version "22.1"
  :group 'gnus-summary
  :type 'hook)

(defcustom gnus-summary-display-arrow
  (and (fboundp 'display-graphic-p)
       (display-graphic-p))
  "*If non-nil, display an arrow highlighting the current article."
  :version "22.1"
  :group 'gnus-summary
  :type 'boolean)

(defcustom gnus-summary-selected-face 'gnus-summary-selected
  "Face used for highlighting the current article in the summary buffer."
  :group 'gnus-summary-visual
  :type 'face)

(defvar gnus-tmp-downloaded nil)

(defcustom gnus-summary-highlight
  '(((eq mark gnus-canceled-mark)
     . gnus-summary-cancelled)
    ((and uncached (> score default-high))
     . gnus-summary-high-undownloaded)
    ((and uncached (< score default-low))
     . gnus-summary-low-undownloaded)
    (uncached
     . gnus-summary-normal-undownloaded)
    ((and (> score default-high)
          (or (eq mark gnus-dormant-mark)
              (eq mark gnus-ticked-mark)))
     . gnus-summary-high-ticked)
    ((and (< score default-low)
          (or (eq mark gnus-dormant-mark)
              (eq mark gnus-ticked-mark)))
     . gnus-summary-low-ticked)
    ((or (eq mark gnus-dormant-mark)
         (eq mark gnus-ticked-mark))
     . gnus-summary-normal-ticked)
    ((and (> score default-high) (eq mark gnus-ancient-mark))
     . gnus-summary-high-ancient)
    ((and (< score default-low) (eq mark gnus-ancient-mark))
     . gnus-summary-low-ancient)
    ((eq mark gnus-ancient-mark)
     . gnus-summary-normal-ancient)
    ((and (> score default-high) (eq mark gnus-unread-mark))
     . gnus-summary-high-unread)
    ((and (< score default-low) (eq mark gnus-unread-mark))
     . gnus-summary-low-unread)
    ((eq mark gnus-unread-mark)
     . gnus-summary-normal-unread)
    ((> score default-high)
     . gnus-summary-high-read)
    ((< score default-low)
     . gnus-summary-low-read)
    (t
     . gnus-summary-normal-read))
  "*Controls the highlighting of summary buffer lines.

A list of (FORM . FACE) pairs.  When deciding how a particular
summary line should be displayed, each form is evaluated.  The content
of the face field after the first true form is used.  You can change
how those summary lines are displayed, by editing the face field.

You can use the following variables in the FORM field.

score:        The article's score.
default:      The default article score.
default-high: The default score for high scored articles.
default-low:  The default score for low scored articles.
below:        The score below which articles are automatically marked as read.
mark:         The article's mark.
uncached:     Non-nil if the article is uncached."
  :group 'gnus-summary-visual
  :type '(repeat (cons (sexp :tag "Form" nil)
                       face)))
(put 'gnus-summary-highlight 'risky-local-variable t)

(defcustom gnus-alter-header-function nil
  "Function called to allow alteration of article header structures.
The function is called with one parameter, the article header vector,
which it may alter in any way."
  :type '(choice (const :tag "None" nil)
                 function)
  :group 'gnus-summary)

(defvar gnus-decode-encoded-word-function 'mail-decode-encoded-word-string
  "Function used to decode a string with encoded words.")

(defvar gnus-decode-encoded-address-function
  'mail-decode-encoded-address-string
  "Function used to decode addresses with encoded words.")

(defcustom gnus-extra-headers '(To Cc Keywords Gcc Newsgroups)
  "*Extra headers to parse."
  :version "24.1"                       ; added Cc Keywords Gcc
  :group 'gnus-summary
  :type '(repeat symbol))

(defcustom gnus-ignored-from-addresses
  (and user-mail-address
       (not (string= user-mail-address ""))
       (regexp-quote user-mail-address))
  "*From headers that may be suppressed in favor of To headers.
This can be a regexp or a list of regexps."
  :version "21.1"
  :group 'gnus-summary
  :type '(choice regexp
                 (repeat :tag "Regexp List" regexp)))

(defsubst gnus-ignored-from-addresses ()
  (gmm-regexp-concat gnus-ignored-from-addresses))

(defcustom gnus-summary-to-prefix "-> "
  "*String prefixed to the To field in the summary line when
using `gnus-ignored-from-addresses'."
  :version "22.1"
  :group 'gnus-summary
  :type 'string)

(defcustom gnus-summary-newsgroup-prefix "=> "
  "*String prefixed to the Newsgroup field in the summary
line when using `gnus-ignored-from-addresses'."
  :version "22.1"
  :group 'gnus-summary
  :type 'string)

(defcustom gnus-newsgroup-ignored-charsets '(unknown-8bit x-unknown)
  "List of charsets that should be ignored.
When these charsets are used in the \"charset\" parameter, the
default charset will be used instead."
  :version "21.1"
  :type '(repeat symbol)
  :group 'gnus-charset)

(defcustom gnus-newsgroup-maximum-articles nil
  "The maximum number of articles a newsgroup.
If this is a number, old articles in a newsgroup exceeding this number
are silently ignored.  If it is nil, no article is ignored.  Note that
setting this variable to a number might prevent you from reading very
old articles."
  :group 'gnus-group-select
  :version "22.2"
  :type '(choice (const :tag "No limit" nil)
                 integer))

(gnus-define-group-parameter
 ignored-charsets
 :type list
 :function-document
 "Return the ignored charsets of GROUP."
 :variable gnus-group-ignored-charsets-alist
 :variable-default
 '(("alt\\.chinese\\.text" iso-8859-1))
 :variable-document
 "Alist of regexps (to match group names) and charsets that should be ignored.
When these charsets are used in the \"charset\" parameter, the
default charset will be used instead."
 :variable-group gnus-charset
 :variable-type '(repeat (cons (regexp :tag "Group")
                               (repeat symbol)))
 :parameter-type '(choice :tag "Ignored charsets"
                          :value nil
                          (repeat (symbol)))
 :parameter-document       "\
List of charsets that should be ignored.

When these charsets are used in the \"charset\" parameter, the
default charset will be used instead.")

(defcustom gnus-group-highlight-words-alist nil
  "Alist of group regexps and highlight regexps.
This variable uses the same syntax as `gnus-emphasis-alist'."
  :version "21.1"
  :type '(repeat (cons (regexp :tag "Group")
                       (repeat (list (regexp :tag "Highlight regexp")
                                     (number :tag "Group for entire word" 0)
                                     (number :tag "Group for displayed part" 0)
                                     (symbol :tag "Face"
                                             gnus-emphasis-highlight-words)))))
  :group 'gnus-summary-visual)

(defcustom gnus-summary-show-article-charset-alist
  nil
  "Alist of number and charset.
The article will be shown with the charset corresponding to the
numbered argument.
For example: ((1 . cn-gb-2312) (2 . big5))."
  :version "21.1"
  :type '(repeat (cons (number :tag "Argument" 1)
                       (symbol :tag "Charset")))
  :group 'gnus-charset)

(defcustom gnus-preserve-marks t
  "Whether marks are preserved when moving, copying and respooling messages."
  :version "21.1"
  :type 'boolean
  :group 'gnus-summary-marks)

(defcustom gnus-propagate-marks nil
  "If non-nil, Gnus will store and retrieve marks from the backends.
This means that marks will be stored both in .newsrc.eld and in
the backend, and will slow operation down somewhat."
  :type 'boolean
  :group 'gnus-summary-marks)

(defcustom gnus-alter-articles-to-read-function nil
  "Function to be called to alter the list of articles to be selected."
  :type '(choice (const nil) function)
  :group 'gnus-summary)

(defcustom gnus-orphan-score nil
  "*All orphans get this score added.  Set in the score file."
  :group 'gnus-score-default
  :type '(choice (const nil)
                 integer))

(defcustom gnus-summary-save-parts-default-mime "image/.*"
  "*A regexp to match MIME parts when saving multiple parts of a
message with `gnus-summary-save-parts' (\\<gnus-summary-mode-map>\\[gnus-summary-save-parts]).
This regexp will be used by default when prompting the user for which
type of files to save."
  :group 'gnus-summary
  :type 'regexp)

(defcustom gnus-read-all-available-headers nil
  "Whether Gnus should parse all headers made available to it.
This is mostly relevant for slow back ends where the user may
wish to widen the summary buffer to include all headers
that were fetched."
  :version "22.1"
  :group 'gnus-summary
  :type '(choice boolean regexp))

(defcustom gnus-summary-pipe-output-default-command nil
  "Command (and optional arguments) used to pipe article to subprocess.
This will be used as the default command if it is non-nil.  The value
will be updated if you modify it when executing the command
`gnus-summary-pipe-output' or the function `gnus-summary-save-in-pipe'."
  :version "23.1" ;; No Gnus
  :group 'gnus-summary
  :type '(radio (const :tag "None" nil) (string :tag "Command")))

(defcustom gnus-summary-muttprint-program "muttprint"
  "Command (and optional arguments) used to run Muttprint.
The value will be updated if you modify it when executing the command
`gnus-summary-muttprint'."
  :version "22.1"
  :group 'gnus-summary
  :type 'string)

(defcustom gnus-article-loose-mime t
  "If non-nil, don't require MIME-Version header.
Some brain-damaged MUA/MTA, e.g. Lotus Domino 5.0.6 clients, does not
supply the MIME-Version header or deliberately strip it from the mail.
If non-nil (the default), Gnus will treat some articles as MIME
even if the MIME-Version header is missing."
  :version "22.1"
  :type 'boolean
  :group 'gnus-article-mime)

(defcustom gnus-article-emulate-mime t
  "If non-nil, use MIME emulation for uuencode and the like.
This means that Gnus will search message bodies for text that look
like uuencoded bits, yEncoded bits, and so on, and present that using
the normal Gnus MIME machinery."
  :version "22.1"
  :type 'boolean
  :group 'gnus-article-mime)

;;; Internal variables

(defvar gnus-summary-display-cache nil)
(defvar gnus-article-mime-handles nil)
(defvar gnus-article-decoded-p nil)
(defvar gnus-article-charset nil)
(defvar gnus-article-ignored-charsets nil)
(defvar gnus-scores-exclude-files nil)
(defvar gnus-page-broken nil)

(defvar gnus-original-article nil)
(defvar gnus-article-internal-prepare-hook nil)
(defvar gnus-newsgroup-process-stack nil)

(defvar gnus-thread-indent-array nil)
(defvar gnus-thread-indent-array-level gnus-thread-indent-level)
(defvar gnus-sort-gathered-threads-function 'gnus-thread-sort-by-number
  "Function called to sort the articles within a thread after it has been gathered together.")

(defvar gnus-summary-save-parts-type-history nil)
(defvar gnus-summary-save-parts-last-directory mm-default-directory)

;; Avoid highlighting in kill files.
(defvar gnus-summary-inhibit-highlight nil)
(defvar gnus-newsgroup-selected-overlay nil)
(defvar gnus-inhibit-limiting nil)
(defvar gnus-newsgroup-adaptive-score-file nil)
(defvar gnus-current-score-file nil)
(defvar gnus-current-move-group nil)
(defvar gnus-current-copy-group nil)
(defvar gnus-current-crosspost-group nil)
(defvar gnus-newsgroup-display nil)

(defvar gnus-newsgroup-dependencies nil)
(defvar gnus-newsgroup-adaptive nil)
(defvar gnus-summary-display-article-function nil)
(defvar gnus-summary-highlight-line-function nil
  "Function called after highlighting a summary line.")

(defvar gnus-summary-line-format-alist
  `((?N ,(macroexpand '(mail-header-number gnus-tmp-header)) ?d)
    (?S ,(macroexpand '(mail-header-subject gnus-tmp-header)) ?s)
    (?s gnus-tmp-subject-or-nil ?s)
    (?n gnus-tmp-name ?s)
    (?A (car (cdr (funcall gnus-extract-address-components gnus-tmp-from)))
        ?s)
    (?a (or (car (funcall gnus-extract-address-components gnus-tmp-from))
            gnus-tmp-from) ?s)
    (?F gnus-tmp-from ?s)
    (?x ,(macroexpand '(mail-header-xref gnus-tmp-header)) ?s)
    (?D ,(macroexpand '(mail-header-date gnus-tmp-header)) ?s)
    (?d (gnus-dd-mmm (mail-header-date gnus-tmp-header)) ?s)
    (?o (gnus-date-iso8601 (mail-header-date gnus-tmp-header)) ?s)
    (?M ,(macroexpand '(mail-header-id gnus-tmp-header)) ?s)
    (?r ,(macroexpand '(mail-header-references gnus-tmp-header)) ?s)
    (?c (or (mail-header-chars gnus-tmp-header) 0) ?d)
    (?k (gnus-summary-line-message-size gnus-tmp-header) ?s)
    (?L gnus-tmp-lines ?s)
    (?Z (or (nnir-article-rsv (mail-header-number gnus-tmp-header))
            0) ?d)
    (?G (or (nnir-article-group (mail-header-number gnus-tmp-header))
            "") ?s)
    (?g (or (gnus-group-short-name
             (nnir-article-group (mail-header-number gnus-tmp-header)))
            "") ?s)
    (?O gnus-tmp-downloaded ?c)
    (?I gnus-tmp-indentation ?s)
    (?T (if (= gnus-tmp-level 0) "" (make-string (frame-width) ? )) ?s)
    (?R gnus-tmp-replied ?c)
    (?\[ gnus-tmp-opening-bracket ?c)
    (?\] gnus-tmp-closing-bracket ?c)
    (?\> (make-string gnus-tmp-level ? ) ?s)
    (?\< (make-string (max 0 (- 20 gnus-tmp-level)) ? ) ?s)
    (?i gnus-tmp-score ?d)
    (?z gnus-tmp-score-char ?c)
    (?V (gnus-thread-total-score (and (boundp 'thread) (car thread))) ?d)
    (?U gnus-tmp-unread ?c)
    (?f (gnus-summary-from-or-to-or-newsgroups gnus-tmp-header gnus-tmp-from)
        ?s)
    (?t (gnus-summary-number-of-articles-in-thread
         (and (boundp 'thread) (car thread)) gnus-tmp-level)
        ?d)
    (?e (gnus-summary-number-of-articles-in-thread
         (and (boundp 'thread) (car thread)) gnus-tmp-level t)
        ?c)
    (?u gnus-tmp-user-defined ?s)
    (?P (gnus-pick-line-number) ?d)
    (?B gnus-tmp-thread-tree-header-string ?s)
    (user-date (gnus-user-date
                ,(macroexpand '(mail-header-date gnus-tmp-header))) ?s))
  "An alist of format specifications that can appear in summary lines.
These are paired with what variables they correspond with, along with
the type of the variable (string, integer, character, etc).")

(defvar gnus-summary-dummy-line-format-alist
  `((?S gnus-tmp-subject ?s)
    (?N gnus-tmp-number ?d)
    (?u gnus-tmp-user-defined ?s)))

(defvar gnus-summary-mode-line-format-alist
  `((?G gnus-tmp-group-name ?s)
    (?g (gnus-short-group-name gnus-tmp-group-name) ?s)
    (?p (gnus-group-real-name gnus-tmp-group-name) ?s)
    (?A gnus-tmp-article-number ?d)
    (?Z gnus-tmp-unread-and-unselected ?s)
    (?V gnus-version ?s)
    (?U gnus-tmp-unread-and-unticked ?d)
    (?S gnus-tmp-subject ?s)
    (?e gnus-tmp-unselected ?d)
    (?u gnus-tmp-user-defined ?s)
    (?d (length gnus-newsgroup-dormant) ?d)
    (?t (length gnus-newsgroup-marked) ?d)
    (?h (length gnus-newsgroup-spam-marked) ?d)
    (?r (length gnus-newsgroup-reads) ?d)
    (?z (gnus-summary-article-score gnus-tmp-article-number) ?d)
    (?E gnus-newsgroup-expunged-tally ?d)
    (?s (gnus-current-score-file-nondirectory) ?s)))

;; This is here rather than in gnus-art for compilation reasons.
(defvar gnus-article-mode-line-format-alist
  (nconc '((?w (gnus-article-wash-status) ?s)
           (?m (gnus-article-mime-part-status) ?s))
         gnus-summary-mode-line-format-alist))

(defvar gnus-last-search-regexp nil
  "Default regexp for article search command.")

(defvar gnus-last-shell-command nil
  "Default shell command on article.")

(defvar gnus-newsgroup-agentized nil
  "Locally bound in each summary buffer to indicate whether the server has been agentized.")
(defvar gnus-newsgroup-begin nil)
(defvar gnus-newsgroup-end nil)
(defvar gnus-newsgroup-last-rmail nil)
(defvar gnus-newsgroup-last-mail nil)
(defvar gnus-newsgroup-last-folder nil)
(defvar gnus-newsgroup-last-file nil)
(defvar gnus-newsgroup-last-directory nil)
(defvar gnus-newsgroup-auto-expire nil)
(defvar gnus-newsgroup-active nil)
(defvar gnus-newsgroup-highest nil)

(defvar gnus-newsgroup-data nil)
(defvar gnus-newsgroup-data-reverse nil)
(defvar gnus-newsgroup-limit nil)
(defvar gnus-newsgroup-limits nil)
(defvar gnus-summary-use-undownloaded-faces nil)

(defvar gnus-newsgroup-unreads nil
  "Sorted list of unread articles in the current newsgroup.")

(defvar gnus-newsgroup-unselected nil
  "Sorted list of unselected unread articles in the current newsgroup.")

(defvar gnus-newsgroup-reads nil
  "Alist of read articles and article marks in the current newsgroup.")

(defvar gnus-newsgroup-expunged-tally nil)

(defvar gnus-newsgroup-marked nil
  "Sorted list of ticked articles in the current newsgroup (a subset of unread art).")

(defvar gnus-newsgroup-spam-marked nil
  "List of ranges of articles that have been marked as spam.")

(defvar gnus-newsgroup-killed nil
  "List of ranges of articles that have been through the scoring process.")

(defvar gnus-newsgroup-cached nil
  "Sorted list of articles that come from the article cache.")

(defvar gnus-newsgroup-saved nil
  "List of articles that have been saved.")

(defvar gnus-newsgroup-kill-headers nil)

(defvar gnus-newsgroup-replied nil
  "List of articles that have been replied to in the current newsgroup.")

(defvar gnus-newsgroup-forwarded nil
  "List of articles that have been forwarded in the current newsgroup.")

(defvar gnus-newsgroup-expirable nil
  "Sorted list of articles in the current newsgroup that can be expired.")

(defvar gnus-newsgroup-processable nil
  "List of articles in the current newsgroup that can be processed.")

(defvar gnus-newsgroup-downloadable nil
  "Sorted list of articles in the current newsgroup that can be processed.")

(defvar gnus-newsgroup-unfetched nil
  "Sorted list of articles in the current newsgroup whose headers have
not been fetched into the agent.

This list will always be a subset of gnus-newsgroup-undownloaded.")

(defvar gnus-newsgroup-undownloaded nil
  "List of articles in the current newsgroup that haven't been downloaded.")

(defvar gnus-newsgroup-unsendable nil
  "List of articles in the current newsgroup that won't be sent.")

(defvar gnus-newsgroup-bookmarks nil
  "List of articles in the current newsgroup that have bookmarks.")

(defvar gnus-newsgroup-dormant nil
  "Sorted list of dormant articles in the current newsgroup.")

(defvar gnus-newsgroup-unseen nil
  "List of unseen articles in the current newsgroup.")

(defvar gnus-newsgroup-seen nil
  "Range of seen articles in the current newsgroup.")

(defvar gnus-newsgroup-articles nil
  "List of articles in the current newsgroup.")

(defvar gnus-newsgroup-scored nil
  "List of scored articles in the current newsgroup.")

(defvar gnus-newsgroup-headers nil
  "List of article headers in the current newsgroup.")

(defvar gnus-newsgroup-threads nil)

(defvar gnus-newsgroup-prepared nil
  "Whether the current group has been prepared properly.")

(defvar gnus-newsgroup-ancient nil
  "List of `gnus-fetch-old-headers' articles in the current newsgroup.")

(defvar gnus-newsgroup-sparse nil)

(defvar gnus-current-article nil)
(defvar gnus-article-current nil)
(defvar gnus-current-headers nil)
(defvar gnus-have-all-headers nil)
(defvar gnus-last-article nil)
(defvar gnus-newsgroup-history nil)
(defvar gnus-newsgroup-charset nil)
(defvar gnus-newsgroup-ephemeral-charset nil)
(defvar gnus-newsgroup-ephemeral-ignored-charsets nil)

(defvar gnus-article-before-search nil)

(defvar gnus-summary-local-variables
  '(gnus-newsgroup-name

    ;; Marks lists
    gnus-newsgroup-unreads
    gnus-newsgroup-unselected
    gnus-newsgroup-marked
    gnus-newsgroup-spam-marked
    gnus-newsgroup-reads
    gnus-newsgroup-saved
    gnus-newsgroup-replied
    gnus-newsgroup-forwarded
    gnus-newsgroup-expirable
    gnus-newsgroup-killed
    gnus-newsgroup-unseen
    gnus-newsgroup-seen
    gnus-newsgroup-cached
    gnus-newsgroup-downloadable
    gnus-newsgroup-undownloaded
    gnus-newsgroup-unsendable

    gnus-newsgroup-begin gnus-newsgroup-end
    gnus-newsgroup-last-rmail gnus-newsgroup-last-mail
    gnus-newsgroup-last-folder gnus-newsgroup-last-file
    gnus-newsgroup-last-directory
    gnus-newsgroup-auto-expire
    gnus-newsgroup-processable
    gnus-newsgroup-unfetched
    gnus-newsgroup-articles
    gnus-newsgroup-bookmarks gnus-newsgroup-dormant
    gnus-newsgroup-headers gnus-newsgroup-threads
    gnus-newsgroup-prepared gnus-summary-highlight-line-function
    gnus-current-article gnus-current-headers gnus-have-all-headers
    gnus-last-article gnus-article-internal-prepare-hook
    (gnus-summary-article-delete-hook . global)
    (gnus-summary-article-move-hook . global)
    gnus-newsgroup-dependencies gnus-newsgroup-selected-overlay
    gnus-newsgroup-scored gnus-newsgroup-kill-headers
    gnus-thread-expunge-below
    gnus-score-alist gnus-current-score-file
    (gnus-summary-expunge-below . global)
    (gnus-summary-mark-below . global)
    (gnus-orphan-score . global)
    gnus-newsgroup-active gnus-scores-exclude-files
    gnus-newsgroup-highest
    gnus-newsgroup-history gnus-newsgroup-ancient
    gnus-newsgroup-sparse gnus-newsgroup-process-stack
    (gnus-newsgroup-adaptive . gnus-use-adaptive-scoring)
    gnus-newsgroup-adaptive-score-file (gnus-reffed-article-number . -1)
    (gnus-newsgroup-expunged-tally . 0)
    gnus-cache-removable-articles
    gnus-newsgroup-data gnus-newsgroup-data-reverse
    gnus-newsgroup-limit gnus-newsgroup-limits
    gnus-newsgroup-charset gnus-newsgroup-display
    gnus-summary-use-undownloaded-faces)
  "Variables that are buffer-local to the summary buffers.")

(defvar gnus-newsgroup-variables nil
  "A list of variables that have separate values in different newsgroups.
A list of newsgroup (summary buffer) local variables, or cons of
variables and their default expressions to be evalled (when the default
values are not nil), that should be made global while the summary buffer
is active.

Note: The default expressions will be evaluated (using function `eval')
before assignment to the local variable rather than just assigned to it.
If the default expression is the symbol `global', that symbol will not
be evaluated but the global value of the local variable will be used
instead.

These variables can be used to set variables in the group parameters
while still allowing them to affect operations done in other buffers.
For example:

\(setq gnus-newsgroup-variables
     '(message-use-followup-to
       (gnus-visible-headers .
         \"^From:\\\\|^Newsgroups:\\\\|^Subject:\\\\|^Date:\\\\|^To:\")))
")

(eval-when-compile
  ;; Bind features so that require will believe that gnus-sum has
  ;; already been loaded (avoids infinite recursion)
  (let ((features (cons 'gnus-sum features)))
    (require 'gnus-art)))

;; MIME stuff.

(defvar gnus-decode-encoded-word-methods
  '(mail-decode-encoded-word-string)
  "List of methods used to decode encoded words.

This variable is a list of FUNCTION or (REGEXP . FUNCTION).  If item
is FUNCTION, FUNCTION will be apply to all newsgroups.  If item is a
\(REGEXP . FUNCTION), FUNCTION will be applied only to the newsgroups
whose names match REGEXP.

For example:
\((\"chinese\" . gnus-decode-encoded-word-string-by-guess)
 mail-decode-encoded-word-string
 (\"chinese\" . rfc1843-decode-string))")

(defvar gnus-decode-encoded-word-methods-cache nil)

(defun gnus-multi-decode-encoded-word-string (string)
  "Apply the functions from `gnus-encoded-word-methods' that match."
  (unless (and gnus-decode-encoded-word-methods-cache
               (eq gnus-newsgroup-name
                   (car gnus-decode-encoded-word-methods-cache)))
    (setq gnus-decode-encoded-word-methods-cache (list gnus-newsgroup-name))
    (dolist (method gnus-decode-encoded-word-methods)
      (if (symbolp method)
          (nconc gnus-decode-encoded-word-methods-cache (list method))
        (if (and gnus-newsgroup-name
                 (string-match (car method) gnus-newsgroup-name))
            (nconc gnus-decode-encoded-word-methods-cache
                   (list (cdr method)))))))
  (dolist (method (cdr gnus-decode-encoded-word-methods-cache) string)
    (setq string (funcall method string))))

;; Subject simplification.

(defun gnus-simplify-whitespace (str)
  "Remove excessive whitespace from STR."
  ;; Multiple spaces.
  (while (string-match "[ \t][ \t]+" str)
    (setq str (concat (substring str 0 (match-beginning 0))
                        " "
                        (substring str (match-end 0)))))
  ;; Leading spaces.
  (when (string-match "^[ \t]+" str)
    (setq str (substring str (match-end 0))))
  ;; Trailing spaces.
  (when (string-match "[ \t]+$" str)
    (setq str (substring str 0 (match-beginning 0))))
  str)

(defun gnus-simplify-all-whitespace (str)
  "Remove all whitespace from STR."
  (while (string-match "[ \t\n]+" str)
    (setq str (replace-match "" nil nil str)))
  str)

(defsubst gnus-simplify-subject-re (subject)
  "Remove \"Re:\" from subject lines."
  (if (string-match message-subject-re-regexp subject)
      (substring subject (match-end 0))
    subject))

(defun gnus-simplify-subject (subject &optional re-only)
  "Remove `Re:' and words in parentheses.
If RE-ONLY is non-nil, strip leading `Re:'s only."
  (let ((case-fold-search t))           ;Ignore case.
    ;; Remove `Re:', `Re^N:', `Re(n)', and `Re[n]:'.
    (when (string-match "\\`\\(re\\([[(^][0-9]+[])]?\\)?:[ \t]*\\)+" subject)
      (setq subject (substring subject (match-end 0))))
    ;; Remove uninteresting prefixes.
    (when (and (not re-only)
               gnus-simplify-ignored-prefixes
               (string-match gnus-simplify-ignored-prefixes subject))
      (setq subject (substring subject (match-end 0))))
    ;; Remove words in parentheses from end.
    (unless re-only
      (while (string-match "[ \t\n]*([^()]*)[ \t\n]*\\'" subject)
        (setq subject (substring subject 0 (match-beginning 0)))))
    ;; Return subject string.
    subject))

;; Remove any leading "re:"s, any trailing paren phrases, and simplify
;; all whitespace.
(defsubst gnus-simplify-buffer-fuzzy-step (regexp &optional newtext)
  (goto-char (point-min))
  (while (re-search-forward regexp nil t)
    (replace-match (or newtext ""))))

(defun gnus-simplify-buffer-fuzzy (regexp)
  "Simplify string in the buffer fuzzily.
The string in the accessible portion of the current buffer is simplified.
It is assumed to be a single-line subject.
Whitespace is generally cleaned up, and miscellaneous leading/trailing
matter is removed.  Additional things can be deleted by setting
`gnus-simplify-subject-fuzzy-regexp'."
  (let ((case-fold-search t)
        (modified-tick))
    (gnus-simplify-buffer-fuzzy-step "\t" " ")

    (while (not (eq modified-tick (buffer-modified-tick)))
      (setq modified-tick (buffer-modified-tick))
      (cond
       ((listp regexp)
        (mapc 'gnus-simplify-buffer-fuzzy-step regexp))
       (regexp
        (gnus-simplify-buffer-fuzzy-step regexp)))
      (gnus-simplify-buffer-fuzzy-step "^ *\\[[-+?*!][-+?*!]\\] *")
      (gnus-simplify-buffer-fuzzy-step
       "^ *\\(re\\|fw\\|fwd\\)[[{(^0-9]*[])}]?[:;] *")
      (gnus-simplify-buffer-fuzzy-step "^[[].*:\\( .*\\)[]]$" "\\1"))

    (gnus-simplify-buffer-fuzzy-step " *[[{(][^()\n]*[]})] *$")
    (gnus-simplify-buffer-fuzzy-step "  +" " ")
    (gnus-simplify-buffer-fuzzy-step " $")
    (gnus-simplify-buffer-fuzzy-step "^ +")))

(defun gnus-simplify-subject-fuzzy (subject)
  "Simplify a subject string fuzzily.
See `gnus-simplify-buffer-fuzzy' for details."
  (save-excursion
    (let ((regexp gnus-simplify-subject-fuzzy-regexp))
      (gnus-set-work-buffer)
      (let ((case-fold-search t))
        ;; Remove uninteresting prefixes.
        (when (and gnus-simplify-ignored-prefixes
                   (string-match gnus-simplify-ignored-prefixes subject))
          (setq subject (substring subject (match-end 0))))
        (insert subject)
        (inline (gnus-simplify-buffer-fuzzy regexp))
        (buffer-string)))))

(defsubst gnus-simplify-subject-fully (subject)
  "Simplify a subject string according to `gnus-summary-gather-subject-limit'."
  (cond
   (gnus-simplify-subject-functions
    (gnus-map-function gnus-simplify-subject-functions subject))
   ((null gnus-summary-gather-subject-limit)
    (gnus-simplify-subject-re subject))
   ((eq gnus-summary-gather-subject-limit 'fuzzy)
    (gnus-simplify-subject-fuzzy subject))
   ((numberp gnus-summary-gather-subject-limit)
    (truncate-string-to-width (gnus-simplify-subject-re subject)
                              gnus-summary-gather-subject-limit))
   (t
    subject)))

(defsubst gnus-subject-equal (s1 s2 &optional simple-first)
  "Check whether two subjects are equal.
If optional argument SIMPLE-FIRST is t, first argument is already
simplified."
  (cond
   ((null simple-first)
    (equal (gnus-simplify-subject-fully s1)
           (gnus-simplify-subject-fully s2)))
   (t
    (equal s1
           (gnus-simplify-subject-fully s2)))))

(defun gnus-summary-bubble-group ()
  "Increase the score of the current group.
This is a handy function to add to `gnus-summary-exit-hook' to
increase the score of each group you read."
  (gnus-group-add-score gnus-newsgroup-name))

\f
;;;
;;; Gnus summary mode
;;;

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

(defvar gnus-article-commands-menu)

;; Non-orthogonal keys

(gnus-define-keys gnus-summary-mode-map
  " " gnus-summary-next-page
  "\177" gnus-summary-prev-page
  [delete] gnus-summary-prev-page
  [backspace] gnus-summary-prev-page
  "\r" gnus-summary-scroll-up
  "\M-\r" gnus-summary-scroll-down
  "n" gnus-summary-next-unread-article
  "p" gnus-summary-prev-unread-article
  "N" gnus-summary-next-article
  "P" gnus-summary-prev-article
  "\M-\C-n" gnus-summary-next-same-subject
  "\M-\C-p" gnus-summary-prev-same-subject
  "\M-n" gnus-summary-next-unread-subject
  "\M-p" gnus-summary-prev-unread-subject
  "." gnus-summary-first-unread-article
  "," gnus-summary-best-unread-article
  "\M-s" gnus-summary-search-article-forward
  "\M-r" gnus-summary-search-article-backward
  "\M-S" gnus-summary-repeat-search-article-forward
  "\M-R" gnus-summary-repeat-search-article-backward
  "<" gnus-summary-beginning-of-article
  ">" gnus-summary-end-of-article
  "j" gnus-summary-goto-article
  "^" gnus-summary-refer-parent-article
  "\M-^" gnus-summary-refer-article
  "u" gnus-summary-tick-article-forward
  "!" gnus-summary-tick-article-forward
  "U" gnus-summary-tick-article-backward
  "d" gnus-summary-mark-as-read-forward
  "D" gnus-summary-mark-as-read-backward
  "E" gnus-summary-mark-as-expirable
  "\M-u" gnus-summary-clear-mark-forward
  "\M-U" gnus-summary-clear-mark-backward
  "k" gnus-summary-kill-same-subject-and-select
  "\C-k" gnus-summary-kill-same-subject
  "\M-\C-k" gnus-summary-kill-thread
  "\M-\C-l" gnus-summary-lower-thread
  "e" gnus-summary-edit-article
  "#" gnus-summary-mark-as-processable
  "\M-#" gnus-summary-unmark-as-processable
  "\M-\C-t" gnus-summary-toggle-threads
  "\M-\C-s" gnus-summary-show-thread
  "\M-\C-h" gnus-summary-hide-thread
  "\M-\C-f" gnus-summary-next-thread
  "\M-\C-b" gnus-summary-prev-thread
  [(meta down)] gnus-summary-next-thread
  [(meta up)] gnus-summary-prev-thread
  "\M-\C-u" gnus-summary-up-thread
  "\M-\C-d" gnus-summary-down-thread
  "&" gnus-summary-execute-command
  "c" gnus-summary-catchup-and-exit
  "\C-w" gnus-summary-mark-region-as-read
  "\C-t" gnus-summary-toggle-truncation
  "?" gnus-summary-mark-as-dormant
  "\C-c\M-\C-s" gnus-summary-limit-include-expunged
  "\C-c\C-s\C-n" gnus-summary-sort-by-number
  "\C-c\C-s\C-m\C-n" gnus-summary-sort-by-most-recent-number
  "\C-c\C-s\C-l" gnus-summary-sort-by-lines
  "\C-c\C-s\C-c" gnus-summary-sort-by-chars
  "\C-c\C-s\C-a" gnus-summary-sort-by-author
  "\C-c\C-s\C-t" gnus-summary-sort-by-recipient
  "\C-c\C-s\C-s" gnus-summary-sort-by-subject
  "\C-c\C-s\C-d" gnus-summary-sort-by-date
  "\C-c\C-s\C-m\C-d" gnus-summary-sort-by-most-recent-date
  "\C-c\C-s\C-i" gnus-summary-sort-by-score
  "\C-c\C-s\C-o" gnus-summary-sort-by-original
  "\C-c\C-s\C-r" gnus-summary-sort-by-random
  "=" gnus-summary-expand-window
  "\C-x\C-s" gnus-summary-reselect-current-group
  "\M-g" gnus-summary-rescan-group
  "\C-c\C-r" gnus-summary-caesar-message
  "f" gnus-summary-followup
  "F" gnus-summary-followup-with-original
  "C" gnus-summary-cancel-article
  "r" gnus-summary-reply
  "R" gnus-summary-reply-with-original
  "\C-c\C-f" gnus-summary-mail-forward
  "o" gnus-summary-save-article
  "\C-o" gnus-summary-save-article-mail
  "|" gnus-summary-pipe-output
  "\M-k" gnus-summary-edit-local-kill
  "\M-K" gnus-summary-edit-global-kill
  ;; "V" gnus-version
  "\C-c\C-d" gnus-summary-describe-group
  "q" gnus-summary-exit
  "Q" gnus-summary-exit-no-update
  "\C-c\C-i" gnus-info-find-node
  gnus-mouse-2 gnus-mouse-pick-article
  [follow-link] mouse-face
  "m" gnus-summary-mail-other-window
  "a" gnus-summary-post-news
  "x" gnus-summary-limit-to-unread
  "s" gnus-summary-isearch-article
  [tab] gnus-summary-widget-forward
  "t" gnus-summary-toggle-header
  "g" gnus-summary-show-article
  "l" gnus-summary-goto-last-article
  "\C-c\C-v\C-v" gnus-uu-decode-uu-view
  "\C-d" gnus-summary-enter-digest-group
  "\M-\C-d" gnus-summary-read-document
  "\M-\C-e" gnus-summary-edit-parameters
  "\M-\C-a" gnus-summary-customize-parameters
  "\C-c\C-b" gnus-bug
  "*" gnus-cache-enter-article
  "\M-*" gnus-cache-remove-article
  "\M-&" gnus-summary-universal-argument
  "\C-l" gnus-recenter
  "I" gnus-summary-increase-score
  "L" gnus-summary-lower-score
  "\M-i" gnus-symbolic-argument
  "h" gnus-summary-select-article-buffer

  "b" gnus-article-view-part
  "\M-t" gnus-summary-toggle-display-buttonized

  "V" gnus-summary-score-map
  "X" gnus-uu-extract-map
  "S" gnus-summary-send-map)

;; Sort of orthogonal keymap
(gnus-define-keys (gnus-summary-mark-map "M" gnus-summary-mode-map)
  "t" gnus-summary-tick-article-forward
  "!" gnus-summary-tick-article-forward
  "d" gnus-summary-mark-as-read-forward
  "r" gnus-summary-mark-as-read-forward
  "c" gnus-summary-clear-mark-forward
  " " gnus-summary-clear-mark-forward
  "e" gnus-summary-mark-as-expirable
  "x" gnus-summary-mark-as-expirable
  "?" gnus-summary-mark-as-dormant
  "b" gnus-summary-set-bookmark
  "B" gnus-summary-remove-bookmark
  "#" gnus-summary-mark-as-processable
  "\M-#" gnus-summary-unmark-as-processable
  "S" gnus-summary-limit-include-expunged
  "C" gnus-summary-catchup
  "H" gnus-summary-catchup-to-here
  "h" gnus-summary-catchup-from-here
  "\C-c" gnus-summary-catchup-all
  "k" gnus-summary-kill-same-subject-and-select
  "K" gnus-summary-kill-same-subject
  "P" gnus-uu-mark-map)

(gnus-define-keys (gnus-summary-mscore-map "V" gnus-summary-mark-map)
  "c" gnus-summary-clear-above
  "u" gnus-summary-tick-above
  "m" gnus-summary-mark-above
  "k" gnus-summary-kill-below)

(gnus-define-keys (gnus-summary-limit-map "/" gnus-summary-mode-map)
  "/" gnus-summary-limit-to-subject
  "n" gnus-summary-limit-to-articles
  "b" gnus-summary-limit-to-bodies
  "h" gnus-summary-limit-to-headers
  "w" gnus-summary-pop-limit
  "s" gnus-summary-limit-to-subject
  "a" gnus-summary-limit-to-author
  "u" gnus-summary-limit-to-unread
  "m" gnus-summary-limit-to-marks
  "M" gnus-summary-limit-exclude-marks
  "v" gnus-summary-limit-to-score
  "*" gnus-summary-limit-include-cached
  "D" gnus-summary-limit-include-dormant
  "T" gnus-summary-limit-include-thread
  "d" gnus-summary-limit-exclude-dormant
  "t" gnus-summary-limit-to-age
  "." gnus-summary-limit-to-unseen
  "x" gnus-summary-limit-to-extra
  "p" gnus-summary-limit-to-display-predicate
  "E" gnus-summary-limit-include-expunged
  "c" gnus-summary-limit-exclude-childless-dormant
  "C" gnus-summary-limit-mark-excluded-as-read
  "o" gnus-summary-insert-old-articles
  "N" gnus-summary-insert-new-articles
  "S" gnus-summary-limit-to-singletons
  "r" gnus-summary-limit-to-replied
  "R" gnus-summary-limit-to-recipient
  "A" gnus-summary-limit-to-address)

(gnus-define-keys (gnus-summary-goto-map "G" gnus-summary-mode-map)
  "n" gnus-summary-next-unread-article
  "p" gnus-summary-prev-unread-article
  "N" gnus-summary-next-article
  "P" gnus-summary-prev-article
  "\C-n" gnus-summary-next-same-subject
  "\C-p" gnus-summary-prev-same-subject
  "\M-n" gnus-summary-next-unread-subject
  "\M-p" gnus-summary-prev-unread-subject
  "f" gnus-summary-first-unread-article
  "b" gnus-summary-best-unread-article
  "j" gnus-summary-goto-article
  "g" gnus-summary-goto-subject
  "l" gnus-summary-goto-last-article
  "o" gnus-summary-pop-article)

(gnus-define-keys (gnus-summary-thread-map "T" gnus-summary-mode-map)
  "k" gnus-summary-kill-thread
  "E" gnus-summary-expire-thread
  "l" gnus-summary-lower-thread
  "i" gnus-summary-raise-thread
  "T" gnus-summary-toggle-threads
  "t" gnus-summary-rethread-current
  "^" gnus-summary-reparent-thread
  "\M-^" gnus-summary-reparent-children
  "s" gnus-summary-show-thread
  "S" gnus-summary-show-all-threads
  "h" gnus-summary-hide-thread
  "H" gnus-summary-hide-all-threads
  "n" gnus-summary-next-thread
  "p" gnus-summary-prev-thread
  "u" gnus-summary-up-thread
  "o" gnus-summary-top-thread
  "d" gnus-summary-down-thread
  "#" gnus-uu-mark-thread
  "\M-#" gnus-uu-unmark-thread)

(gnus-define-keys (gnus-summary-buffer-map "Y" gnus-summary-mode-map)
  "g" gnus-summary-prepare
  "c" gnus-summary-insert-cached-articles
  "d" gnus-summary-insert-dormant-articles
  "t" gnus-summary-insert-ticked-articles)

(gnus-define-keys (gnus-summary-exit-map "Z" gnus-summary-mode-map)
  "c" gnus-summary-catchup-and-exit
  "C" gnus-summary-catchup-all-and-exit
  "E" gnus-summary-exit-no-update
  "Q" gnus-summary-exit
  "Z" gnus-summary-exit
  "n" gnus-summary-catchup-and-goto-next-group
  "p" gnus-summary-catchup-and-goto-prev-group
  "R" gnus-summary-reselect-current-group
  "G" gnus-summary-rescan-group
  "N" gnus-summary-next-group
  "s" gnus-summary-save-newsrc
  "P" gnus-summary-prev-group)

(gnus-define-keys (gnus-summary-article-map "A" gnus-summary-mode-map)
  " " gnus-summary-next-page
  "n" gnus-summary-next-page
  "\177" gnus-summary-prev-page
  [delete] gnus-summary-prev-page
  "p" gnus-summary-prev-page
  "\r" gnus-summary-scroll-up
  "\M-\r" gnus-summary-scroll-down
  "<" gnus-summary-beginning-of-article
  ">" gnus-summary-end-of-article
  "b" gnus-summary-beginning-of-article
  "e" gnus-summary-end-of-article
  "^" gnus-summary-refer-parent-article
  "r" gnus-summary-refer-parent-article
  "C" gnus-summary-show-complete-article
  "D" gnus-summary-enter-digest-group
  "R" gnus-summary-refer-references
  "T" gnus-summary-refer-thread
  "W" gnus-warp-to-article
  "g" gnus-summary-show-article
  "s" gnus-summary-isearch-article
  [tab] gnus-summary-widget-forward
  "P" gnus-summary-print-article
  "S" gnus-sticky-article
  "M" gnus-mailing-list-insinuate
  "t" gnus-article-babel)

(gnus-define-keys (gnus-summary-wash-map "W" gnus-summary-mode-map)
  "b" gnus-article-add-buttons
  "B" gnus-article-add-buttons-to-head
  "o" gnus-article-treat-overstrike
  "e" gnus-article-emphasize
  "w" gnus-article-fill-cited-article
  "Q" gnus-article-fill-long-lines
  "L" gnus-article-toggle-truncate-lines
  "C" gnus-article-capitalize-sentences
  "c" gnus-article-remove-cr
  "q" gnus-article-de-quoted-unreadable
  "6" gnus-article-de-base64-unreadable
  "Z" gnus-article-decode-HZ
  "A" gnus-article-treat-ansi-sequences
  "h" gnus-article-wash-html
  "u" gnus-article-unsplit-urls
  "s" gnus-summary-force-verify-and-decrypt
  "f" gnus-article-display-x-face
  "l" gnus-summary-stop-page-breaking
  "r" gnus-summary-caesar-message
  "m" gnus-summary-morse-message
  "t" gnus-summary-toggle-header
  "g" gnus-treat-smiley
  "v" gnus-summary-verbose-headers
  "a" gnus-article-strip-headers-in-body ;; mnemonic: wash archive
  "p" gnus-article-verify-x-pgp-sig
  "d" gnus-article-treat-dumbquotes
  "U" gnus-article-treat-non-ascii
  "i" gnus-summary-idna-message)

(gnus-define-keys (gnus-summary-wash-deuglify-map "Y" gnus-summary-wash-map)
  ;; mnemonic: deuglif*Y*
  "u" gnus-article-outlook-unwrap-lines
  "a" gnus-article-outlook-repair-attribution
  "c" gnus-article-outlook-rearrange-citation
  "f" gnus-article-outlook-deuglify-article) ;; mnemonic: full deuglify

(gnus-define-keys (gnus-summary-wash-hide-map "W" gnus-summary-wash-map)
  "a" gnus-article-hide
  "h" gnus-article-hide-headers
  "b" gnus-article-hide-boring-headers
  "s" gnus-article-hide-signature
  "c" gnus-article-hide-citation
  "C" gnus-article-hide-citation-in-followups
  "l" gnus-article-hide-list-identifiers
  "B" gnus-article-strip-banner
  "P" gnus-article-hide-pem
  "\C-c" gnus-article-hide-citation-maybe)

(gnus-define-keys (gnus-summary-wash-highlight-map "H" gnus-summary-wash-map)
  "a" gnus-article-highlight
  "h" gnus-article-highlight-headers
  "c" gnus-article-highlight-citation
  "s" gnus-article-highlight-signature)

(gnus-define-keys (gnus-summary-wash-header-map "G" gnus-summary-wash-map)
  "f" gnus-article-treat-fold-headers
  "u" gnus-article-treat-unfold-headers
  "n" gnus-article-treat-fold-newsgroups)

(gnus-define-keys (gnus-summary-wash-display-map "D" gnus-summary-wash-map)
  "x" gnus-article-display-x-face
  "d" gnus-article-display-face
  "s" gnus-treat-smiley
  "D" gnus-article-remove-images
  "W" gnus-article-show-images
  "f" gnus-treat-from-picon
  "m" gnus-treat-mail-picon
  "n" gnus-treat-newsgroups-picon
  "g" gnus-treat-from-gravatar
  "h" gnus-treat-mail-gravatar)

(gnus-define-keys (gnus-summary-wash-mime-map "M" gnus-summary-wash-map)
  "w" gnus-article-decode-mime-words
  "c" gnus-article-decode-charset
  "v" gnus-mime-view-all-parts
  "b" gnus-article-view-part)

(gnus-define-keys (gnus-summary-wash-time-map "T" gnus-summary-wash-map)
  "z" gnus-article-date-ut
  "u" gnus-article-date-ut
  "l" gnus-article-date-local
  "p" gnus-article-date-english
  "e" gnus-article-date-lapsed
  "o" gnus-article-date-original
  "i" gnus-article-date-iso8601
  "s" gnus-article-date-user)

(gnus-define-keys (gnus-summary-wash-empty-map "E" gnus-summary-wash-map)
  "t" gnus-article-remove-trailing-blank-lines
  "l" gnus-article-strip-leading-blank-lines
  "m" gnus-article-strip-multiple-blank-lines
  "a" gnus-article-strip-blank-lines
  "A" gnus-article-strip-all-blank-lines
  "s" gnus-article-strip-leading-space
  "e" gnus-article-strip-trailing-space
  "w" gnus-article-remove-leading-whitespace)

(gnus-define-keys (gnus-summary-help-map "H" gnus-summary-mode-map)
  "v" gnus-version
  "d" gnus-summary-describe-group
  "h" gnus-summary-describe-briefly
  "i" gnus-info-find-node)

(gnus-define-keys (gnus-summary-backend-map "B" gnus-summary-mode-map)
  "e" gnus-summary-expire-articles
  "\M-\C-e" gnus-summary-expire-articles-now
  "\177" gnus-summary-delete-article
  [delete] gnus-summary-delete-article
  [backspace] gnus-summary-delete-article
  "m" gnus-summary-move-article
  "r" gnus-summary-respool-article
  "w" gnus-summary-edit-article
  "c" gnus-summary-copy-article
  "B" gnus-summary-crosspost-article
  "q" gnus-summary-respool-query
  "t" gnus-summary-respool-trace
  "i" gnus-summary-import-article
  "I" gnus-summary-create-article
  "p" gnus-summary-article-posted-p)

(gnus-define-keys (gnus-summary-save-map "O" gnus-summary-mode-map)
  "o" gnus-summary-save-article
  "m" gnus-summary-save-article-mail
  "F" gnus-summary-write-article-file
  "r" gnus-summary-save-article-rmail
  "f" gnus-summary-save-article-file
  "b" gnus-summary-save-article-body-file
  "B" gnus-summary-write-article-body-file
  "h" gnus-summary-save-article-folder
  "v" gnus-summary-save-article-vm
  "p" gnus-summary-pipe-output
  "P" gnus-summary-muttprint)

(gnus-define-keys (gnus-summary-mime-map "K" gnus-summary-mode-map)
  "b" gnus-summary-display-buttonized
  "m" gnus-summary-repair-multipart
  "v" gnus-article-view-part
  "o" gnus-article-save-part
  "O" gnus-article-save-part-and-strip
  "r" gnus-article-replace-part
  "d" gnus-article-delete-part
  "t" gnus-article-view-part-as-type
  "j" gnus-article-jump-to-part
  "c" gnus-article-copy-part
  "C" gnus-article-view-part-as-charset
  "e" gnus-article-view-part-externally
  "H" gnus-article-browse-html-article
  "E" gnus-article-encrypt-body
  "i" gnus-article-inline-part
  "|" gnus-article-pipe-part)

(gnus-define-keys (gnus-uu-mark-map "P" gnus-summary-mark-map)
  "p" gnus-summary-mark-as-processable
  "u" gnus-summary-unmark-as-processable
  "U" gnus-summary-unmark-all-processable
  "v" gnus-uu-mark-over
  "s" gnus-uu-mark-series
  "r" gnus-uu-mark-region
  "g" gnus-uu-unmark-region
  "R" gnus-uu-mark-by-regexp
  "G" gnus-uu-unmark-by-regexp
  "t" gnus-uu-mark-thread
  "T" gnus-uu-unmark-thread
  "a" gnus-uu-mark-all
  "b" gnus-uu-mark-buffer
  "S" gnus-uu-mark-sparse
  "k" gnus-summary-kill-process-mark
  "y" gnus-summary-yank-process-mark
  "w" gnus-summary-save-process-mark
  "i" gnus-uu-invert-processable)

(gnus-define-keys (gnus-uu-extract-map "X" gnus-summary-mode-map)
  ;;"x" gnus-uu-extract-any
  "m" gnus-summary-save-parts
  "u" gnus-uu-decode-uu
  "U" gnus-uu-decode-uu-and-save
  "s" gnus-uu-decode-unshar
  "S" gnus-uu-decode-unshar-and-save
  "o" gnus-uu-decode-save
  "O" gnus-uu-decode-save
  "b" gnus-uu-decode-binhex
  "B" gnus-uu-decode-binhex
  "Y" gnus-uu-decode-yenc
  "p" gnus-uu-decode-postscript
  "P" gnus-uu-decode-postscript-and-save)

(gnus-define-keys
    (gnus-uu-extract-view-map "v" gnus-uu-extract-map)
  "u" gnus-uu-decode-uu-view
  "U" gnus-uu-decode-uu-and-save-view
  "s" gnus-uu-decode-unshar-view
  "S" gnus-uu-decode-unshar-and-save-view
  "o" gnus-uu-decode-save-view
  "O" gnus-uu-decode-save-view
  "b" gnus-uu-decode-binhex-view
  "B" gnus-uu-decode-binhex-view
  "p" gnus-uu-decode-postscript-view
  "P" gnus-uu-decode-postscript-and-save-view)

(defvar gnus-article-post-menu nil)

(defconst gnus-summary-menu-maxlen 20)

(defun gnus-summary-menu-split (menu)
  ;; If we have lots of elements, divide them into groups of 20
  ;; and make a pane (or submenu) for each one.
  (if (> (length menu) (/ (* gnus-summary-menu-maxlen 3) 2))
      (let ((menu menu) sublists next
            (i 1))
        (while menu
          ;; Pull off the next gnus-summary-menu-maxlen elements
          ;; and make them the next element of sublist.
          (setq next (nthcdr gnus-summary-menu-maxlen menu))
          (if next
              (setcdr (nthcdr (1- gnus-summary-menu-maxlen) menu)
                      nil))
          (setq sublists (cons (cons (format "%s ... %s" (aref (car menu) 0)
                                             (aref (car (last menu)) 0)) menu)
                               sublists))
          (setq i (1+ i))
          (setq menu next))
        (nreverse sublists))
    ;; Few elements--put them all in one pane.
    menu))

(defun gnus-summary-make-menu-bar ()
  (gnus-turn-off-edit-menu 'summary)

  (unless (boundp 'gnus-summary-misc-menu)

    (easy-menu-define
      gnus-summary-kill-menu gnus-summary-mode-map ""
      (cons
       "Score"
       (nconc
        (list
         ["Customize" gnus-score-customize t])
        (gnus-make-score-map 'increase)
        (gnus-make-score-map 'lower)
        '(("Mark"
           ["Kill below" gnus-summary-kill-below t]
           ["Mark above" gnus-summary-mark-above t]
           ["Tick above" gnus-summary-tick-above t]
           ["Clear above" gnus-summary-clear-above t])
          ["Current score" gnus-summary-current-score t]
          ["Set score" gnus-summary-set-score t]
          ["Switch current score file..." gnus-score-change-score-file t]
          ["Set mark below..." gnus-score-set-mark-below t]
          ["Set expunge below..." gnus-score-set-expunge-below t]
          ["Edit current score file" gnus-score-edit-current-scores t]
          ["Edit score file..." gnus-score-edit-file t]
          ["Trace score" gnus-score-find-trace t]
          ["Find words" gnus-score-find-favourite-words t]
          ["Rescore buffer" gnus-summary-rescore t]
          ["Increase score..." gnus-summary-increase-score t]
          ["Lower score..." gnus-summary-lower-score t]))))

    ;; Define both the Article menu in the summary buffer and the
    ;; equivalent Commands menu in the article buffer here for
    ;; consistency.
    (let ((innards
           `(("Hide"
              ["All" gnus-article-hide t]
              ["Headers" gnus-article-hide-headers t]
              ["Signature" gnus-article-hide-signature t]
              ["Citation" gnus-article-hide-citation t]
              ["List identifiers" gnus-article-hide-list-identifiers t]
              ["Banner" gnus-article-strip-banner t]
              ["Boring headers" gnus-article-hide-boring-headers t])
             ("Highlight"
              ["All" gnus-article-highlight t]
              ["Headers" gnus-article-highlight-headers t]
              ["Signature" gnus-article-highlight-signature t]
              ["Citation" gnus-article-highlight-citation t])
             ("MIME"
              ["Words" gnus-article-decode-mime-words t]
              ["Charset" gnus-article-decode-charset t]
              ["QP" gnus-article-de-quoted-unreadable t]
              ["Base64" gnus-article-de-base64-unreadable t]
              ["View MIME buttons" gnus-summary-display-buttonized t]
              ["View all" gnus-mime-view-all-parts t]
              ["Verify and Decrypt" gnus-summary-force-verify-and-decrypt t]
              ["Encrypt body" gnus-article-encrypt-body
               :active (not (gnus-group-read-only-p))
               ,@(if (featurep 'xemacs) nil
                   '(:help "Encrypt the message body on disk"))]
              ["Extract all parts..." gnus-summary-save-parts t]
              ("Multipart"
               ["Repair multipart" gnus-summary-repair-multipart t]
               ["Pipe part..." gnus-article-pipe-part t]
               ["Inline part" gnus-article-inline-part t]
               ["View part as type..." gnus-article-view-part-as-type t]
               ["Encrypt body" gnus-article-encrypt-body
                :active (not (gnus-group-read-only-p))
               ,@(if (featurep 'xemacs) nil
                   '(:help "Encrypt the message body on disk"))]
               ["View part externally" gnus-article-view-part-externally t]
               ["View HTML parts in browser" gnus-article-browse-html-article t]
               ["View part with charset..." gnus-article-view-part-as-charset t]
               ["Copy part" gnus-article-copy-part t]
               ["Save part..." gnus-article-save-part t]
               ["View part" gnus-article-view-part t]))
             ("Date"
              ["Local" gnus-article-date-local t]
              ["ISO8601" gnus-article-date-iso8601 t]
              ["UT" gnus-article-date-ut t]
              ["Original" gnus-article-date-original t]
              ["Lapsed" gnus-article-date-lapsed t]
              ["User-defined" gnus-article-date-user t])
             ("Display"
              ["Remove images" gnus-article-remove-images t]
              ["Toggle smiley" gnus-treat-smiley t]
              ["Show X-Face" gnus-article-display-x-face t]
              ["Show picons in From" gnus-treat-from-picon t]
              ["Show picons in mail headers" gnus-treat-mail-picon t]
              ["Show picons in news headers" gnus-treat-newsgroups-picon t]
              ["Show Gravatars in From" gnus-treat-from-gravatar t]
              ["Show Gravatars in mail headers" gnus-treat-mail-gravatar t]
              ("View as different encoding"
               ,@(gnus-summary-menu-split
                  (mapcar
                   (lambda (cs)
                     ;; Since easymenu under Emacs doesn't allow
                     ;; lambda forms for menu commands, we should
                     ;; provide intern'ed function symbols.
                     (let ((command (intern (format "\
gnus-summary-show-article-from-menu-as-charset-%s" cs))))
                       (fset command
                             `(lambda ()
                                (interactive)
                                (let ((gnus-summary-show-article-charset-alist
                                       '((1 . ,cs))))
                                  (gnus-summary-show-article 1))))
                       `[,(symbol-name cs) ,command t]))
                   (sort (if (fboundp 'coding-system-list)
                             (coding-system-list)
                           (mapcar 'car mm-mime-mule-charset-alist))
                         'string<)))))
             ("Washing"
              ("Remove Blanks"
               ["Leading" gnus-article-strip-leading-blank-lines t]
               ["Multiple" gnus-article-strip-multiple-blank-lines t]
               ["Trailing" gnus-article-remove-trailing-blank-lines t]
               ["All of the above" gnus-article-strip-blank-lines t]
               ["All" gnus-article-strip-all-blank-lines t]
               ["Leading space" gnus-article-strip-leading-space t]
               ["Trailing space" gnus-article-strip-trailing-space t]
               ["Leading space in headers"
                gnus-article-remove-leading-whitespace t])
              ["Overstrike" gnus-article-treat-overstrike t]
              ["Dumb quotes" gnus-article-treat-dumbquotes t]
              ["Non-ASCII" gnus-article-treat-non-ascii t]
              ["Emphasis" gnus-article-emphasize t]
              ["Word wrap" gnus-article-fill-cited-article t]
              ["Fill long lines" gnus-article-fill-long-lines t]
              ["Toggle truncate long lines" gnus-article-toggle-truncate-lines t]
              ["Capitalize sentences" gnus-article-capitalize-sentences t]
              ["Remove CR" gnus-article-remove-cr t]
              ["Quoted-Printable" gnus-article-de-quoted-unreadable t]
              ["Base64" gnus-article-de-base64-unreadable t]
              ["Rot 13" gnus-summary-caesar-message
               ,@(if (featurep 'xemacs) '(t)
                   '(:help "\"Caesar rotate\" article by 13"))]
              ["De-IDNA" gnus-summary-idna-message t]
              ["Morse decode" gnus-summary-morse-message t]
              ["Unix pipe..." gnus-summary-pipe-message t]
              ["Add buttons" gnus-article-add-buttons t]
              ["Add buttons to head" gnus-article-add-buttons-to-head t]
              ["Stop page breaking" gnus-summary-stop-page-breaking t]
              ["Verbose header" gnus-summary-verbose-headers t]
              ["Toggle header" gnus-summary-toggle-header t]
              ["Unfold headers" gnus-article-treat-unfold-headers t]
              ["Fold newsgroups" gnus-article-treat-fold-newsgroups t]
              ["Html" gnus-article-wash-html t]
              ["Unsplit URLs" gnus-article-unsplit-urls t]
              ["Verify X-PGP-Sig" gnus-article-verify-x-pgp-sig t]
              ["Decode HZ" gnus-article-decode-HZ t]
              ["ANSI sequences" gnus-article-treat-ansi-sequences t]
              ("(Outlook) Deuglify"
               ["Unwrap lines" gnus-article-outlook-unwrap-lines t]
               ["Repair attribution" gnus-article-outlook-repair-attribution t]
               ["Rearrange citation" gnus-article-outlook-rearrange-citation t]
               ["Full (Outlook) deuglify"
                gnus-article-outlook-deuglify-article t])
              )
             ("Output"
              ["Save in default format..." gnus-summary-save-article
               ,@(if (featurep 'xemacs) '(t)
                   '(:help "Save article using default method"))]
              ["Save in file..." gnus-summary-save-article-file
               ,@(if (featurep 'xemacs) '(t)
                   '(:help "Save article in file"))]
              ["Save in Unix mail format..." gnus-summary-save-article-mail t]
              ["Save in MH folder..." gnus-summary-save-article-folder t]
              ["Save in VM folder..." gnus-summary-save-article-vm t]
              ["Save in RMAIL mbox..." gnus-summary-save-article-rmail t]
              ["Save body in file..." gnus-summary-save-article-body-file t]
              ["Pipe through a filter..." gnus-summary-pipe-output t]
              ["Print with Muttprint..." gnus-summary-muttprint t]
              ["Print" gnus-summary-print-article
               ,@(if (featurep 'xemacs) '(t)
                   '(:help "Generate and print a PostScript image"))])
             ("Copy, move,... (Backend)"
              ,@(if (featurep 'xemacs) nil
                  '(:help "Copying, moving, expiring articles..."))
              ["Respool article..." gnus-summary-respool-article t]
              ["Move article..." gnus-summary-move-article
               (gnus-check-backend-function
                'request-move-article gnus-newsgroup-name)]
              ["Copy article..." gnus-summary-copy-article t]
              ["Crosspost article..." gnus-summary-crosspost-article
               (gnus-check-backend-function
                'request-replace-article gnus-newsgroup-name)]
              ["Import file..." gnus-summary-import-article
               (gnus-check-backend-function
                'request-accept-article gnus-newsgroup-name)]
              ["Create article..." gnus-summary-create-article
               (gnus-check-backend-function
                'request-accept-article gnus-newsgroup-name)]
              ["Check if posted" gnus-summary-article-posted-p t]
              ["Edit article" gnus-summary-edit-article
               (not (gnus-group-read-only-p))]
              ["Delete article" gnus-summary-delete-article
               (gnus-check-backend-function
                'request-expire-articles gnus-newsgroup-name)]
              ["Query respool" gnus-summary-respool-query t]
              ["Trace respool" gnus-summary-respool-trace t]
              ["Delete expirable articles" gnus-summary-expire-articles-now
               (gnus-check-backend-function
                'request-expire-articles gnus-newsgroup-name)])
             ("Extract"
              ["Uudecode" gnus-uu-decode-uu
               ,@(if (featurep 'xemacs) '(t)
                   '(:help "Decode uuencoded article(s)"))]
              ["Uudecode and save" gnus-uu-decode-uu-and-save t]
              ["Unshar" gnus-uu-decode-unshar t]
              ["Unshar and save" gnus-uu-decode-unshar-and-save t]
              ["Save" gnus-uu-decode-save t]
              ["Binhex" gnus-uu-decode-binhex t]
              ["PostScript" gnus-uu-decode-postscript t]
              ["All MIME parts" gnus-summary-save-parts t])
             ("Cache"
              ["Enter article" gnus-cache-enter-article t]
              ["Remove article" gnus-cache-remove-article t])
             ["Translate" gnus-article-babel t]
             ["Select article buffer" gnus-summary-select-article-buffer t]
             ["Make article buffer sticky" gnus-sticky-article t]
             ["Enter digest buffer" gnus-summary-enter-digest-group t]
             ["Isearch article..." gnus-summary-isearch-article t]
             ["Beginning of the article" gnus-summary-beginning-of-article t]
             ["End of the article" gnus-summary-end-of-article t]
             ["Fetch parent of article" gnus-summary-refer-parent-article t]
             ["Fetch referenced articles" gnus-summary-refer-references t]
             ["Fetch current thread" gnus-summary-refer-thread t]
             ["Fetch article with id..." gnus-summary-refer-article t]
             ["Setup Mailing List Params" gnus-mailing-list-insinuate t]
             ["Redisplay" gnus-summary-show-article t]
             ["Raw article" gnus-summary-show-raw-article :keys "C-u g"])))
      (easy-menu-define
        gnus-summary-article-menu gnus-summary-mode-map ""
        (cons "Article" innards))

      (if (not (keymapp gnus-summary-article-menu))
          (easy-menu-define
            gnus-article-commands-menu gnus-article-mode-map ""
            (cons "Commands" innards))
        ;; in Emacs, don't share menu.
        (setq gnus-article-commands-menu
              (copy-keymap gnus-summary-article-menu))
        (define-key gnus-article-mode-map [menu-bar commands]
          (cons "Commands" gnus-article-commands-menu))))

    (easy-menu-define
      gnus-summary-thread-menu gnus-summary-mode-map ""
      '("Threads"
        ["Find all messages in thread" gnus-summary-refer-thread t]
        ["Toggle threading" gnus-summary-toggle-threads t]
        ["Hide threads" gnus-summary-hide-all-threads t]
        ["Show threads" gnus-summary-show-all-threads t]
        ["Hide thread" gnus-summary-hide-thread t]
        ["Show thread" gnus-summary-show-thread t]
        ["Go to next thread" gnus-summary-next-thread t]
        ["Go to previous thread" gnus-summary-prev-thread t]
        ["Go down thread" gnus-summary-down-thread t]
        ["Go up thread" gnus-summary-up-thread t]
        ["Top of thread" gnus-summary-top-thread t]
        ["Mark thread as read" gnus-summary-kill-thread t]
        ["Mark thread as expired" gnus-summary-expire-thread t]
        ["Lower thread score" gnus-summary-lower-thread t]
        ["Raise thread score" gnus-summary-raise-thread t]
        ["Rethread current" gnus-summary-rethread-current t]))

    (easy-menu-define
      gnus-summary-post-menu gnus-summary-mode-map ""
      `("Post"
        ["Send a message (mail or news)" gnus-summary-post-news
         ,@(if (featurep 'xemacs) '(t)
             '(:help "Compose a new message (mail or news)"))]
        ["Followup" gnus-summary-followup
         ,@(if (featurep 'xemacs) '(t)
             '(:help "Post followup to this article"))]
        ["Followup and yank" gnus-summary-followup-with-original
         ,@(if (featurep 'xemacs) '(t)
             '(:help "Post followup to this article, quoting its contents"))]
        ["Supersede article" gnus-summary-supersede-article t]
        ["Cancel article" gnus-summary-cancel-article
         ,@(if (featurep 'xemacs) '(t)
             '(:help "Cancel an article you posted"))]
        ["Reply" gnus-summary-reply t]
        ["Reply and yank" gnus-summary-reply-with-original t]
        ["Wide reply" gnus-summary-wide-reply t]
        ["Wide reply and yank" gnus-summary-wide-reply-with-original
         ,@(if (featurep 'xemacs) '(t)
             '(:help "Mail a reply, quoting this article"))]
        ["Very wide reply" gnus-summary-very-wide-reply t]
        ["Very wide reply and yank" gnus-summary-very-wide-reply-with-original
         ,@(if (featurep 'xemacs) '(t)
             '(:help "Mail a very wide reply, quoting this article"))]
        ["Mail forward" gnus-summary-mail-forward t]
        ["Post forward" gnus-summary-post-forward t]
        ["Digest and mail" gnus-uu-digest-mail-forward t]
        ["Digest and post" gnus-uu-digest-post-forward t]
        ["Resend message" gnus-summary-resend-message t]
        ["Resend message edit" gnus-summary-resend-message-edit t]
        ["Send bounced mail" gnus-summary-resend-bounced-mail t]
        ["Send a mail" gnus-summary-mail-other-window t]
        ["Create a local message" gnus-summary-news-other-window t]
        ["Uuencode and post" gnus-uu-post-news
         ,@(if (featurep 'xemacs) '(t)
             '(:help "Post a uuencoded article"))]
        ["Followup via news" gnus-summary-followup-to-mail t]
        ["Followup via news and yank"
         gnus-summary-followup-to-mail-with-original t]
        ["Strip signature on reply"
         (lambda ()
           (interactive)
           (if (not (memq message-cite-function
                          '(message-cite-original-without-signature
                            message-cite-original)))
               ;; Stupid workaround for XEmacs not honoring :visible.
               (message "Can't toggle this value of `message-cite-function'")
             (setq message-cite-function
                   (if (eq message-cite-function
                           'message-cite-original-without-signature)
                       'message-cite-original
                     'message-cite-original-without-signature))))
         ;; XEmacs barfs on :visible.
         ,@(if (featurep 'xemacs) nil
             '(:visible (memq message-cite-function
                              '(message-cite-original-without-signature
                                message-cite-original))))
         :style toggle
         :selected (eq message-cite-function
                       'message-cite-original-without-signature)
         ,@(if (featurep 'xemacs) nil
             '(:help "Strip signature from cited article when replying."))]
        ;;("Draft"
        ;;["Send" gnus-summary-send-draft t]
        ;;["Send bounced" gnus-resend-bounced-mail t])
        ))

    (cond
     ((not (keymapp gnus-summary-post-menu))
      (setq gnus-article-post-menu gnus-summary-post-menu))
     ((not gnus-article-post-menu)
      ;; Don't share post menu.
      (setq gnus-article-post-menu
            (copy-keymap gnus-summary-post-menu))))
    (define-key gnus-article-mode-map [menu-bar post]
      (cons "Post" gnus-article-post-menu))

    (easy-menu-define
      gnus-summary-misc-menu gnus-summary-mode-map ""
      `("Gnus"
        ("Mark Read"
         ["Mark as read" gnus-summary-mark-as-read-forward t]
         ["Mark same subject and select"
          gnus-summary-kill-same-subject-and-select t]
         ["Mark same subject" gnus-summary-kill-same-subject t]
         ["Catchup" gnus-summary-catchup
          ,@(if (featurep 'xemacs) '(t)
              '(:help "Mark unread articles in this group as read"))]
         ["Catchup all" gnus-summary-catchup-all t]
         ["Catchup to here" gnus-summary-catchup-to-here t]
         ["Catchup from here" gnus-summary-catchup-from-here t]
         ["Catchup region" gnus-summary-mark-region-as-read
          (gnus-mark-active-p)]
         ["Mark excluded" gnus-summary-limit-mark-excluded-as-read t])
        ("Mark Various"
         ["Tick" gnus-summary-tick-article-forward t]
         ["Mark as dormant" gnus-summary-mark-as-dormant t]
         ["Remove marks" gnus-summary-clear-mark-forward t]
         ["Set expirable mark" gnus-summary-mark-as-expirable t]
         ["Set bookmark" gnus-summary-set-bookmark t]
         ["Remove bookmark" gnus-summary-remove-bookmark t])
        ("Limit to"
         ["Marks..." gnus-summary-limit-to-marks t]
         ["Subject..." gnus-summary-limit-to-subject t]
         ["Author..." gnus-summary-limit-to-author t]
         ["Recipient..." gnus-summary-limit-to-recipient t]
         ["Address..." gnus-summary-limit-to-address t]
         ["Age..." gnus-summary-limit-to-age t]
         ["Extra..." gnus-summary-limit-to-extra t]
         ["Score..." gnus-summary-limit-to-score t]
         ["Display Predicate" gnus-summary-limit-to-display-predicate t]
         ["Unread" gnus-summary-limit-to-unread t]
         ["Unseen" gnus-summary-limit-to-unseen t]
         ["Singletons" gnus-summary-limit-to-singletons t]
         ["Replied" gnus-summary-limit-to-replied t]
         ["Non-dormant" gnus-summary-limit-exclude-dormant t]
         ["Next or process marked articles" gnus-summary-limit-to-articles t]
         ["Pop limit" gnus-summary-pop-limit t]
         ["Show dormant" gnus-summary-limit-include-dormant t]
         ["Hide childless dormant"
          gnus-summary-limit-exclude-childless-dormant t]
         ;;["Hide thread" gnus-summary-limit-exclude-thread t]
         ["Hide marked" gnus-summary-limit-exclude-marks t]
         ["Show expunged" gnus-summary-limit-include-expunged t])
        ("Process Mark"
         ["Set mark" gnus-summary-mark-as-processable t]
         ["Remove mark" gnus-summary-unmark-as-processable t]
         ["Remove all marks" gnus-summary-unmark-all-processable t]
         ["Invert marks" gnus-uu-invert-processable t]
         ["Mark above" gnus-uu-mark-over t]
         ["Mark series" gnus-uu-mark-series t]
         ["Mark region" gnus-uu-mark-region (gnus-mark-active-p)]
         ["Unmark region" gnus-uu-unmark-region (gnus-mark-active-p)]
         ["Mark by regexp..." gnus-uu-mark-by-regexp t]
         ["Unmark by regexp..." gnus-uu-unmark-by-regexp t]
         ["Mark all" gnus-uu-mark-all t]
         ["Mark buffer" gnus-uu-mark-buffer t]
         ["Mark sparse" gnus-uu-mark-sparse t]
         ["Mark thread" gnus-uu-mark-thread t]
         ["Unmark thread" gnus-uu-unmark-thread t]
         ("Process Mark Sets"
          ["Kill" gnus-summary-kill-process-mark t]
          ["Yank" gnus-summary-yank-process-mark
           gnus-newsgroup-process-stack]
          ["Save" gnus-summary-save-process-mark t]
          ["Run command on marked..." gnus-summary-universal-argument t]))
        ("Registry Marks")
        ("Scroll article"
         ["Page forward" gnus-summary-next-page
          ,@(if (featurep 'xemacs) '(t)
              '(:help "Show next page of article"))]
         ["Page backward" gnus-summary-prev-page
          ,@(if (featurep 'xemacs) '(t)
              '(:help "Show previous page of article"))]
         ["Line forward" gnus-summary-scroll-up t])
        ("Move"
         ["Next unread article" gnus-summary-next-unread-article t]
         ["Previous unread article" gnus-summary-prev-unread-article t]
         ["Next article" gnus-summary-next-article t]
         ["Previous article" gnus-summary-prev-article t]
         ["Next unread subject" gnus-summary-next-unread-subject t]
         ["Previous unread subject" gnus-summary-prev-unread-subject t]
         ["Next article same subject" gnus-summary-next-same-subject t]
         ["Previous article same subject" gnus-summary-prev-same-subject t]
         ["First unread article" gnus-summary-first-unread-article t]
         ["Best unread article" gnus-summary-best-unread-article t]
         ["Go to subject number..." gnus-summary-goto-subject t]
         ["Go to article number..." gnus-summary-goto-article t]
         ["Go to the last article" gnus-summary-goto-last-article t]
         ["Pop article off history" gnus-summary-pop-article t])
        ("Sort"
         ["Sort by number" gnus-summary-sort-by-number t]
         ["Sort by most recent number" gnus-summary-sort-by-most-recent-number t]
         ["Sort by author" gnus-summary-sort-by-author t]
         ["Sort by recipient" gnus-summary-sort-by-recipient t]
         ["Sort by subject" gnus-summary-sort-by-subject t]
         ["Sort by date" gnus-summary-sort-by-date t]
         ["Sort by most recent date" gnus-summary-sort-by-most-recent-date t]
         ["Sort by score" gnus-summary-sort-by-score t]
         ["Sort by lines" gnus-summary-sort-by-lines t]
         ["Sort by characters" gnus-summary-sort-by-chars t]
         ["Randomize" gnus-summary-sort-by-random t]
         ["Original sort" gnus-summary-sort-by-original t])
        ("Help"
         ["Describe group" gnus-summary-describe-group t]
         ["Read manual" gnus-info-find-node t])
        ("Modes"
         ["Pick and read" gnus-pick-mode t]
         ["Binary" gnus-binary-mode t])
        ("Regeneration"
         ["Regenerate" gnus-summary-prepare t]
         ["Insert cached articles" gnus-summary-insert-cached-articles t]
         ["Insert dormant articles" gnus-summary-insert-dormant-articles t]
         ["Insert ticked articles" gnus-summary-insert-ticked-articles t]
         ["Toggle threading" gnus-summary-toggle-threads t])
        ["See old articles" gnus-summary-insert-old-articles t]
        ["See new articles" gnus-summary-insert-new-articles t]
        ["Filter articles..." gnus-summary-execute-command t]
        ["Run command on articles..." gnus-summary-universal-argument t]
        ["Search articles forward..." gnus-summary-search-article-forward t]
        ["Search articles backward..." gnus-summary-search-article-backward t]
        ["Toggle line truncation" gnus-summary-toggle-truncation t]
        ["Expand window" gnus-summary-expand-window t]
        ["Expire expirable articles" gnus-summary-expire-articles
         (gnus-check-backend-function
          'request-expire-articles gnus-newsgroup-name)]
        ["Edit local kill file" gnus-summary-edit-local-kill t]
        ["Edit main kill file" gnus-summary-edit-global-kill t]
        ["Edit group parameters" gnus-summary-edit-parameters t]
        ["Customize group parameters" gnus-summary-customize-parameters t]
        ["Send a bug report" gnus-bug t]
        ("Exit"
         ["Catchup and exit" gnus-summary-catchup-and-exit
          ,@(if (featurep 'xemacs) '(t)
              '(:help "Mark unread articles in this group as read, then exit"))]
         ["Catchup all and exit" gnus-summary-catchup-all-and-exit t]
         ["Catchup and goto next" gnus-summary-catchup-and-goto-next-group t]
         ["Catchup and goto prev" gnus-summary-catchup-and-goto-prev-group t]
         ["Exit group" gnus-summary-exit
          ,@(if (featurep 'xemacs) '(t)
              '(:help "Exit current group, return to group selection mode"))]
         ["Exit group without updating" gnus-summary-exit-no-update t]
         ["Exit and goto next group" gnus-summary-next-group t]
         ["Exit and goto prev group" gnus-summary-prev-group t]
         ["Reselect group" gnus-summary-reselect-current-group t]
         ["Rescan group" gnus-summary-rescan-group t]
         ["Update dribble" gnus-summary-save-newsrc t])))

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

(defvar gnus-summary-tool-bar-map nil)

;; Note: The :set function in the `gnus-summary-tool-bar*' variables will only
;; affect _new_ message buffers.  We might add a function that walks thru all
;; summary-mode buffers and force the update.
(defun gnus-summary-tool-bar-update (&optional symbol value)
  "Update summary mode toolbar.
Setter function for custom variables."
  (setq-default gnus-summary-tool-bar-map nil)
  (when symbol
    ;; When used as ":set" function:
    (set-default symbol value))
  (when (gnus-buffer-live-p gnus-summary-buffer)
    (with-current-buffer gnus-summary-buffer
      (gnus-summary-make-tool-bar))))

(defcustom gnus-summary-tool-bar (if (eq gmm-tool-bar-style 'gnome)
                                     'gnus-summary-tool-bar-gnome
                                   'gnus-summary-tool-bar-retro)
  "Specifies the Gnus summary tool bar.

It can be either a list or a symbol referring to a list.  See
`gmm-tool-bar-from-list' for the format of the list.  The
default key map is `gnus-summary-mode-map'.

Pre-defined symbols include `gnus-summary-tool-bar-gnome' and
`gnus-summary-tool-bar-retro'."
  :type '(choice (const :tag "GNOME style" gnus-summary-tool-bar-gnome)
                 (const :tag "Retro look"  gnus-summary-tool-bar-retro)
                 (repeat :tag "User defined list" gmm-tool-bar-item)
                 (symbol))
  :version "23.1" ;; No Gnus
  :initialize 'custom-initialize-default
  :set 'gnus-summary-tool-bar-update
  :group 'gnus-summary)

(defcustom gnus-summary-tool-bar-gnome
  '((gnus-summary-post-news "mail/compose" nil)
    (gnus-summary-insert-new-articles "mail/inbox" nil
                                      :visible (or (not gnus-agent)
                                                   gnus-plugged))
    (gnus-summary-reply-with-original "mail/reply")
    (gnus-summary-reply "mail/reply" nil :visible nil)
    (gnus-summary-followup-with-original "mail/reply-all")
    (gnus-summary-followup "mail/reply-all" nil :visible nil)
    (gnus-summary-mail-forward "mail/forward")
    (gnus-summary-save-article "mail/save")
    (gnus-summary-search-article-forward "search" nil :visible nil)
    (gnus-summary-print-article "print")
    (gnus-summary-tick-article-forward "flag-followup" nil :visible nil)
    ;; Some new commands that may need more suitable icons:
    (gnus-summary-save-newsrc "save" nil :visible nil)
    ;; (gnus-summary-show-article "stock_message-display" nil :visible nil)
    (gnus-summary-prev-article "left-arrow")
    (gnus-summary-next-article "right-arrow")
    (gnus-summary-next-page "next-page")
    ;; (gnus-summary-enter-digest-group "right_arrow" nil :visible nil)
    ;;
    ;; Maybe some sort-by-... could be added:
    ;; (gnus-summary-sort-by-author "sort-a-z" nil :visible nil)
    ;; (gnus-summary-sort-by-date "sort-1-9" nil :visible nil)
    (gnus-summary-mark-as-expirable
     "delete" nil
     :visible (gnus-check-backend-function 'request-expire-articles
                                           gnus-newsgroup-name))
    (gnus-summary-mark-as-spam
     "mail/spam" t
     :visible (and (fboundp 'spam-group-ham-contents-p)
                   (spam-group-ham-contents-p gnus-newsgroup-name))
     :help "Mark as spam")
    (gnus-summary-mark-as-read-forward
     "mail/not-spam" nil
     :visible (and (fboundp 'spam-group-spam-contents-p)
                   (spam-group-spam-contents-p gnus-newsgroup-name)))
    ;;
    (gnus-summary-exit "exit")
    (gmm-customize-mode "preferences" t :help "Edit mode preferences")
    (gnus-info-find-node "help"))
  "List of functions for the summary tool bar (GNOME style).

See `gmm-tool-bar-from-list' for the format of the list."
  :type '(repeat gmm-tool-bar-item)
  :version "23.1" ;; No Gnus
  :initialize 'custom-initialize-default
  :set 'gnus-summary-tool-bar-update
  :group 'gnus-summary)

(defcustom gnus-summary-tool-bar-retro
  '((gnus-summary-prev-unread-article "gnus/prev-ur")
    (gnus-summary-next-unread-article "gnus/next-ur")
    (gnus-summary-post-news "gnus/post")
    (gnus-summary-followup-with-original "gnus/fuwo")
    (gnus-summary-followup "gnus/followup")
    (gnus-summary-reply-with-original "gnus/reply-wo")
    (gnus-summary-reply "gnus/reply")
    (gnus-summary-caesar-message "gnus/rot13")
    (gnus-uu-decode-uu "gnus/uu-decode")
    (gnus-summary-save-article-file "gnus/save-aif")
    (gnus-summary-save-article "gnus/save-art")
    (gnus-uu-post-news "gnus/uu-post")
    (gnus-summary-catchup "gnus/catchup")
    (gnus-summary-catchup-and-exit "gnus/cu-exit")
    (gnus-summary-exit "gnus/exit-summ")
    ;; Some new command that may need more suitable icons:
    (gnus-summary-print-article "gnus/print" nil :visible nil)
    (gnus-summary-mark-as-expirable "gnus/close" nil :visible nil)
    (gnus-summary-save-newsrc "gnus/save" nil :visible nil)
    ;; (gnus-summary-enter-digest-group "gnus/right_arrow" nil :visible nil)
    (gnus-summary-search-article-forward "gnus/search" nil :visible nil)
    ;; (gnus-summary-insert-new-articles "gnus/paste" nil :visible nil)
    ;; (gnus-summary-toggle-threads "gnus/open" nil :visible nil)
    ;;
    (gnus-info-find-node "gnus/help" nil :visible nil))
  "List of functions for the summary tool bar (retro look).

See `gmm-tool-bar-from-list' for the format of the list."
  :type '(repeat gmm-tool-bar-item)
  :version "23.1" ;; No Gnus
  :initialize 'custom-initialize-default
  :set 'gnus-summary-tool-bar-update
  :group 'gnus-summary)

(defcustom gnus-summary-tool-bar-zap-list t
  "List of icon items from the global tool bar.
These items are not displayed in the Gnus summary mode tool bar.

See `gmm-tool-bar-from-list' for the format of the list."
  :type 'gmm-tool-bar-zap-list
  :version "23.1" ;; No Gnus
  :initialize 'custom-initialize-default
  :set 'gnus-summary-tool-bar-update
  :group 'gnus-summary)

(defvar image-load-path)
(defvar tool-bar-map)

(defun gnus-summary-make-tool-bar (&optional force)
  "Make a summary mode tool bar from `gnus-summary-tool-bar'.
When FORCE, rebuild the tool bar."
  (when (and (not (featurep 'xemacs))
             (boundp 'tool-bar-mode)
             tool-bar-mode
             (or (not gnus-summary-tool-bar-map) force))
    (let* ((load-path
            (gmm-image-load-path-for-library "gnus"
                                             "mail/save.xpm"
                                             nil t))
           (image-load-path (cons (car load-path)
                                  (when (boundp 'image-load-path)
                                    image-load-path)))
           (map (gmm-tool-bar-from-list gnus-summary-tool-bar
                                        gnus-summary-tool-bar-zap-list
                                        'gnus-summary-mode-map)))
      (when map
        ;; Need to set `gnus-summary-tool-bar-map' because `gnus-article-mode'
        ;; uses its value.
        (setq gnus-summary-tool-bar-map map))))
  (set (make-local-variable 'tool-bar-map) gnus-summary-tool-bar-map))

(defun gnus-score-set-default (var value)
  "A version of set that updates the GNU Emacs menu-bar."
  (set var value)
  ;; It is the message that forces the active status to be updated.
  (message ""))

(defun gnus-make-score-map (type)
  "Make a summary score map of type TYPE."
  (if t
      nil
    (let ((headers '(("author" "from" string)
                     ("subject" "subject" string)
                     ("article body" "body" string)
                     ("article head" "head" string)
                     ("xref" "xref" string)
                     ("extra header" "extra" string)
                     ("lines" "lines" number)
                     ("followups to author" "followup" string)))
          (types '((number ("less than" <)
                           ("greater than" >)
                           ("equal" =))
                   (string ("substring" s)
                           ("exact string" e)
                           ("fuzzy string" f)
                           ("regexp" r))))
          (perms '(("temporary" (current-time-string))
                   ("permanent" nil)
                   ("immediate" now)))
          header)
      (list
       (apply
        'nconc
        (list
         (if (eq type 'lower)
             "Lower score"
           "Increase score"))
        (let (outh)
          (while headers
            (setq header (car headers))
            (setq outh
                  (cons
                   (apply
                    'nconc
                    (list (car header))
                    (let ((ts (cdr (assoc (nth 2 header) types)))
                          outt)
                      (while ts
                        (setq outt
                              (cons
                               (apply
                                'nconc
                                (list (caar ts))
                                (let ((ps perms)
                                      outp)
                                  (while ps
                                    (setq outp
                                          (cons
                                           (vector
                                            (caar ps)
                                            (list
                                             'gnus-summary-score-entry
                                             (nth 1 header)
                                             (if (or (string= (nth 1 header)
                                                              "head")
                                                     (string= (nth 1 header)
                                                              "body"))
                                                 ""
                                               (list 'gnus-summary-header
                                                     (nth 1 header)))
                                             (list 'quote (nth 1 (car ts)))
                                             (list 'gnus-score-delta-default
                                                   nil)
                                             (nth 1 (car ps))
                                             t)
                                            t)
                                           outp))
                                    (setq ps (cdr ps)))
                                  (list (nreverse outp))))
                               outt))
                        (setq ts (cdr ts)))
                      (list (nreverse outt))))
                   outh))
            (setq headers (cdr headers)))
          (list (nreverse outh))))))))


(declare-function turn-on-gnus-mailing-list-mode "gnus-ml" ())
(defvar bookmark-make-record-function)
\f
(defvar bidi-paragraph-direction)

(defun gnus-summary-mode (&optional group)
  "Major mode for reading articles.

All normal editing commands are switched off.
\\<gnus-summary-mode-map>
Each line in this buffer represents one article.  To read an
article, you can, for instance, type `\\[gnus-summary-next-page]'.  To move forwards
and backwards while displaying articles, type `\\[gnus-summary-next-unread-article]' and `\\[gnus-summary-prev-unread-article]',
respectively.

You can also post articles and send mail from this buffer.  To
follow up an article, type `\\[gnus-summary-followup]'.  To mail a reply to the author
of an article, type `\\[gnus-summary-reply]'.

There are approx. one gazillion commands you can execute in this
buffer; read the info pages for more information (`\\[gnus-info-find-node]').

The following commands are available:

\\{gnus-summary-mode-map}"
  (interactive)
  (kill-all-local-variables)
  (let ((gnus-summary-local-variables gnus-newsgroup-variables))
    (gnus-summary-make-local-variables))
  (gnus-summary-make-local-variables)
  (setq gnus-newsgroup-name group)
  (when (gnus-visual-p 'summary-menu 'menu)
    (gnus-summary-make-menu-bar)
    (gnus-summary-make-tool-bar))
  (gnus-make-thread-indent-array)
  (gnus-simplify-mode-line)
  (setq major-mode 'gnus-summary-mode)
  (setq mode-name "Summary")
  (use-local-map gnus-summary-mode-map)
  (buffer-disable-undo)
  (setq buffer-read-only t              ;Disable modification
        show-trailing-whitespace nil)
  (setq truncate-lines t)
  ;; Force paragraph direction to be left-to-right.  Don't make it
  ;; bound globally in old Emacsen and XEmacsen.
  (set (make-local-variable 'bidi-paragraph-direction) 'left-to-right)
  (add-to-invisibility-spec '(gnus-sum . t))
  (gnus-summary-set-display-table)
  (gnus-set-default-directory)
  (make-local-variable 'gnus-summary-line-format)
  (make-local-variable 'gnus-summary-line-format-spec)
  (make-local-variable 'gnus-summary-dummy-line-format)
  (make-local-variable 'gnus-summary-dummy-line-format-spec)
  (make-local-variable 'gnus-summary-mark-positions)
  (gnus-make-local-hook 'pre-command-hook)
  (add-hook 'pre-command-hook 'gnus-set-global-variables nil t)
  (gnus-run-mode-hooks 'gnus-summary-mode-hook)
  (turn-on-gnus-mailing-list-mode)
  (mm-enable-multibyte)
  (set (make-local-variable 'bookmark-make-record-function)
       'gnus-summary-bookmark-make-record)
  (gnus-update-format-specifications nil 'summary 'summary-mode 'summary-dummy)
  (gnus-update-summary-mark-positions))

(defun gnus-summary-make-local-variables ()
  "Make all the local summary buffer variables."
  (let (global)
    (dolist (local gnus-summary-local-variables)
      (if (consp local)
          (progn
            (if (eq (cdr local) 'global)
                ;; Copy the global value of the variable.
                (setq global (symbol-value (car local)))
              ;; Use the value from the list.
              (setq global (eval (cdr local))))
            (set (make-local-variable (car local)) global))
        ;; Simple nil-valued local variable.
        (set (make-local-variable local) nil)))))

;; Summary data functions.

(defmacro gnus-data-number (data)
  `(car ,data))

(defmacro gnus-data-set-number (data number)
  `(setcar ,data ,number))

(defmacro gnus-data-mark (data)
  `(nth 1 ,data))

(defmacro gnus-data-set-mark (data mark)
  `(setcar (nthcdr 1 ,data) ,mark))

(defmacro gnus-data-pos (data)
  `(nth 2 ,data))

(defmacro gnus-data-set-pos (data pos)
  `(setcar (nthcdr 2 ,data) ,pos))

(defmacro gnus-data-header (data)
  `(nth 3 ,data))

(defmacro gnus-data-set-header (data header)
  `(setf (nth 3 ,data) ,header))

(defmacro gnus-data-level (data)
  `(nth 4 ,data))

(defmacro gnus-data-unread-p (data)
  `(= (nth 1 ,data) gnus-unread-mark))

(defmacro gnus-data-read-p (data)
  `(/= (nth 1 ,data) gnus-unread-mark))

(defmacro gnus-data-pseudo-p (data)
  `(consp (nth 3 ,data)))

(defmacro gnus-data-find (number)
  `(assq ,number gnus-newsgroup-data))

(defmacro gnus-data-find-list (number &optional data)
  `(let ((bdata ,(or data 'gnus-newsgroup-data)))
     (memq (assq ,number bdata)
           bdata)))

(defmacro gnus-data-make (number mark pos header level)
  `(list ,number ,mark ,pos ,header ,level))

(defun gnus-data-enter (after-article number mark pos header level offset)
  (let ((data (gnus-data-find-list after-article)))
    (unless data
      (error "No such article: %d" after-article))
    (setcdr data (cons (gnus-data-make number mark pos header level)
                       (cdr data)))
    (setq gnus-newsgroup-data-reverse nil)
    (gnus-data-update-list (cddr data) offset)))

(defun gnus-data-enter-list (after-article list &optional offset)
  (when list
    (let ((data (and after-article (gnus-data-find-list after-article)))
          (ilist list))
      (if (not (or data
                   after-article))
          (let ((odata gnus-newsgroup-data))
            (setq gnus-newsgroup-data (nconc list gnus-newsgroup-data))
            (when offset
              (gnus-data-update-list odata offset)))
        ;; Find the last element in the list to be spliced into the main
        ;; list.
        (setq list (last list))
        (if (not data)
            (progn
              (setcdr list gnus-newsgroup-data)
              (setq gnus-newsgroup-data ilist)
              (when offset
                (gnus-data-update-list (cdr list) offset)))
          (setcdr list (cdr data))
          (setcdr data ilist)
          (when offset
            (gnus-data-update-list (cdr list) offset))))
      (setq gnus-newsgroup-data-reverse nil))))

(defun gnus-data-remove (article &optional offset)
  (let ((data gnus-newsgroup-data))
    (if (= (gnus-data-number (car data)) article)
        (progn
          (setq gnus-newsgroup-data (cdr gnus-newsgroup-data)
                gnus-newsgroup-data-reverse nil)
          (when offset
            (gnus-data-update-list gnus-newsgroup-data offset)))
      (while (cdr data)
        (when (= (gnus-data-number (cadr data)) article)
          (setcdr data (cddr data))
          (when offset
            (gnus-data-update-list (cdr data) offset))
          (setq data nil
                gnus-newsgroup-data-reverse nil))
        (setq data (cdr data))))))

(defmacro gnus-data-list (backward)
  `(if ,backward
       (or gnus-newsgroup-data-reverse
           (setq gnus-newsgroup-data-reverse
                 (reverse gnus-newsgroup-data)))
     gnus-newsgroup-data))

(defun gnus-data-update-list (data offset)
  "Add OFFSET to the POS of all data entries in DATA."
  (setq gnus-newsgroup-data-reverse nil)
  (while data
    (setcar (nthcdr 2 (car data)) (+ offset (nth 2 (car data))))
    (setq data (cdr data))))

(defun gnus-summary-article-pseudo-p (article)
  "Say whether this article is a pseudo article or not."
  (not (vectorp (gnus-data-header (gnus-data-find article)))))

(defmacro gnus-summary-article-sparse-p (article)
  "Say whether this article is a sparse article or not."
  `(memq ,article gnus-newsgroup-sparse))

(defmacro gnus-summary-article-ancient-p (article)
  "Say whether this article is a sparse article or not."
  `(memq ,article gnus-newsgroup-ancient))

(defun gnus-article-parent-p (number)
  "Say whether this article is a parent or not."
  (let ((data (gnus-data-find-list number)))
    (and (cdr data)              ; There has to be an article after...
         (< (gnus-data-level (car data)) ; And it has to have a higher level.
            (gnus-data-level (nth 1 data))))))

(defun gnus-article-children (number)
  "Return a list of all children to NUMBER."
  (let* ((data (gnus-data-find-list number))
         (level (gnus-data-level (car data)))
         children)
    (setq data (cdr data))
    (while (and data
                (= (gnus-data-level (car data)) (1+ level)))
      (push (gnus-data-number (car data)) children)
      (setq data (cdr data)))
    children))

(defmacro gnus-summary-skip-intangible ()
  "If the current article is intangible, then jump to a different article."
  '(let ((to (get-text-property (point) 'gnus-intangible)))
     (and to (gnus-summary-goto-subject to))))

(defmacro gnus-summary-article-intangible-p ()
  "Say whether this article is intangible or not."
  '(get-text-property (point) 'gnus-intangible))

(defun gnus-article-read-p (article)
  "Say whether ARTICLE is read or not."
  (not (or (memq article gnus-newsgroup-marked)
           (memq article gnus-newsgroup-spam-marked)
           (memq article gnus-newsgroup-unreads)
           (memq article gnus-newsgroup-unselected)
           (memq article gnus-newsgroup-dormant))))

;; Some summary mode macros.

(defmacro gnus-summary-article-number ()
  "The article number of the article on the current line.
If there isn't an article number here, then we return the current
article number."
  '(progn
     (gnus-summary-skip-intangible)
     (or (get-text-property (point) 'gnus-number)
         (gnus-summary-last-subject))))

(defmacro gnus-summary-article-header (&optional number)
  "Return the header of article NUMBER."
  `(gnus-data-header (gnus-data-find
                      ,(or number '(gnus-summary-article-number)))))

(defmacro gnus-summary-thread-level (&optional number)
  "Return the level of thread that starts with article NUMBER."
  `(if (and (eq gnus-summary-make-false-root 'dummy)
            (get-text-property (point) 'gnus-intangible))
       0
     (gnus-data-level (gnus-data-find
                       ,(or number '(gnus-summary-article-number))))))

(defmacro gnus-summary-article-mark (&optional number)
  "Return the mark of article NUMBER."
  `(gnus-data-mark (gnus-data-find
                    ,(or number '(gnus-summary-article-number)))))

(defmacro gnus-summary-article-pos (&optional number)
  "Return the position of the line of article NUMBER."
  `(gnus-data-pos (gnus-data-find
                   ,(or number '(gnus-summary-article-number)))))

(defalias 'gnus-summary-subject-string 'gnus-summary-article-subject)
(defmacro gnus-summary-article-subject (&optional number)
  "Return current subject string or nil if nothing."
  `(let ((headers
          ,(if number
               `(gnus-data-header (assq ,number gnus-newsgroup-data))
             '(gnus-data-header (assq (gnus-summary-article-number)
                                      gnus-newsgroup-data)))))
     (and headers
          (vectorp headers)
          (mail-header-subject headers))))

(defmacro gnus-summary-article-score (&optional number)
  "Return current article score."
  `(or (cdr (assq ,(or number '(gnus-summary-article-number))
                  gnus-newsgroup-scored))
       gnus-summary-default-score 0))

(defun gnus-summary-article-children (&optional number)
  "Return a list of article numbers that are children of article NUMBER."
  (let* ((data (gnus-data-find-list (or number (gnus-summary-article-number))))
         (level (gnus-data-level (car data)))
         l children)
    (while (and (setq data (cdr data))
                (> (setq l (gnus-data-level (car data))) level))
      (and (= (1+ level) l)
           (push (gnus-data-number (car data))
                 children)))
    (nreverse children)))

(defun gnus-summary-article-parent (&optional number)
  "Return the article number of the parent of article NUMBER."
  (let* ((data (gnus-data-find-list (or number (gnus-summary-article-number))
                                    (gnus-data-list t)))
         (level (gnus-data-level (car data))))
    (if (zerop level)
        ()                              ; This is a root.
      ;; We search until we find an article with a level less than
      ;; this one.  That function has to be the parent.
      (while (and (setq data (cdr data))
                  (not (< (gnus-data-level (car data)) level))))
      (and data (gnus-data-number (car data))))))

(defun gnus-unread-mark-p (mark)
  "Say whether MARK is the unread mark."
  (= mark gnus-unread-mark))

(defun gnus-read-mark-p (mark)
  "Say whether MARK is one of the marks that mark as read.
This is all marks except unread, ticked, dormant, and expirable."
  (not (or (= mark gnus-unread-mark)
           (= mark gnus-ticked-mark)
           (= mark gnus-spam-mark)
           (= mark gnus-dormant-mark)
           (= mark gnus-expirable-mark))))

(defmacro gnus-article-mark (number)
  "Return the MARK of article NUMBER.
This macro should only be used when computing the mark the \"first\"
time; i.e., when generating the summary lines.  After that,
`gnus-summary-article-mark' should be used to examine the
marks of articles."
  `(cond
    ((memq ,number gnus-newsgroup-unsendable) gnus-unsendable-mark)
    ((memq ,number gnus-newsgroup-downloadable) gnus-downloadable-mark)
    ((memq ,number gnus-newsgroup-unreads) gnus-unread-mark)
    ((memq ,number gnus-newsgroup-marked) gnus-ticked-mark)
    ((memq ,number gnus-newsgroup-spam-marked) gnus-spam-mark)
    ((memq ,number gnus-newsgroup-dormant) gnus-dormant-mark)
    ((memq ,number gnus-newsgroup-expirable) gnus-expirable-mark)
    (t (or (cdr (assq ,number gnus-newsgroup-reads))
           gnus-ancient-mark))))

;; Saving hidden threads.

(defmacro gnus-save-hidden-threads (&rest forms)
  "Save hidden threads, eval FORMS, and restore the hidden threads."
  (let ((config (make-symbol "config")))
    `(let ((,config (gnus-hidden-threads-configuration)))
       (unwind-protect
           (save-excursion
             ,@forms)
         (gnus-restore-hidden-threads-configuration ,config)))))
(put 'gnus-save-hidden-threads 'lisp-indent-function 0)
(put 'gnus-save-hidden-threads 'edebug-form-spec '(body))

(defun gnus-data-compute-positions ()
  "Compute the positions of all articles."
  (setq gnus-newsgroup-data-reverse nil)
  (let ((data gnus-newsgroup-data))
    (save-excursion
      (gnus-save-hidden-threads
        (gnus-summary-show-all-threads)
        (goto-char (point-min))
        (while data
          (while (get-text-property (point) 'gnus-intangible)
            (forward-line 1))
          (gnus-data-set-pos (car data) (+ (point) 3))
          (setq data (cdr data))
          (forward-line 1))))))

(defun gnus-hidden-threads-configuration ()
  "Return the current hidden threads configuration."
  (save-excursion
    (let (config)
      (goto-char (point-min))
      (while (not (eobp))
        (when (eq (get-char-property (point-at-eol) 'invisible) 'gnus-sum)
          (push (save-excursion (forward-line 0) (point)) config))
        (forward-line 1))
      config)))

(defun gnus-restore-hidden-threads-configuration (config)
  "Restore hidden threads configuration from CONFIG."
  (save-excursion
    (let (point (inhibit-read-only t))
      (while (setq point (pop config))
        (goto-char point)
        (gnus-summary-hide-thread)))))

;; Various summary mode internalish functions.

(defun gnus-mouse-pick-article (e)
  (interactive "e")
  (mouse-set-point e)
  (gnus-summary-next-page nil t))

(defun gnus-summary-set-display-table ()
  "Change the display table.
Odd characters have a tendency to mess
up nicely formatted displays - we make all possible glyphs
display only a single character."

  ;; We start from the standard display table, if any.
  (let ((table (or (copy-sequence standard-display-table)
                   (make-display-table)))
        (i 32))
    ;; Nix out all the control chars...
    (while (>= (setq i (1- i)) 0)
      (gnus-put-display-table i [??] table))
   ;; ... but not newline and cr, of course.  (cr is necessary for the
    ;; selective display).
    (gnus-put-display-table ?\n nil table)
    (gnus-put-display-table ?\r nil table)
    ;; We keep TAB as well.
    (gnus-put-display-table ?\t nil table)
    ;; We nix out any glyphs 127 through 255, or 127 through 159 in
    ;; Emacs 23 (unicode), that are not set already.
    (let ((i (if (ignore-errors (= (make-char 'latin-iso8859-1 160) 160))
                 160
               256)))
      (while (>= (setq i (1- i)) 127)
        ;; Only modify if the entry is nil.
        (unless (gnus-get-display-table i table)
          (gnus-put-display-table i [??] table))))
    (setq buffer-display-table table)))

(defun gnus-summary-set-article-display-arrow (pos)
  "Update the overlay arrow to point to line at position POS."
  (when gnus-summary-display-arrow
    (make-local-variable 'overlay-arrow-position)
    (make-local-variable 'overlay-arrow-string)
    (save-excursion
      (goto-char pos)
      (beginning-of-line)
      (unless overlay-arrow-position
        (setq overlay-arrow-position (make-marker)))
      (setq overlay-arrow-string "=>"
            overlay-arrow-position (set-marker overlay-arrow-position
                                               (point)
                                               (current-buffer))))))

(defun gnus-summary-setup-buffer (group)
  "Initialize summary buffer.
If the setup was successful, non-nil is returned."
  (let ((buffer (gnus-summary-buffer-name group))
        (dead-name (concat "*Dead Summary "
                           (gnus-group-decoded-name group) "*")))
    ;; If a dead summary buffer exists, we kill it.
    (when (gnus-buffer-live-p dead-name)
      (gnus-kill-buffer dead-name))
    (if (get-buffer buffer)
        (progn
          (set-buffer buffer)
          (setq gnus-summary-buffer (current-buffer))
          (not gnus-newsgroup-prepared))
      ;; Fix by Sudish Joseph <joseph@cis.ohio-state.edu>
      (setq gnus-summary-buffer (set-buffer (gnus-get-buffer-create buffer)))
      (gnus-summary-mode group)
      (when (gnus-group-quit-config group)
        (set (make-local-variable 'gnus-single-article-buffer) nil))
      (make-local-variable 'gnus-article-buffer)
      (make-local-variable 'gnus-article-current)
      (make-local-variable 'gnus-original-article-buffer)
      (setq gnus-newsgroup-name group)
      ;; Set any local variables in the group parameters.
      (gnus-summary-set-local-parameters gnus-newsgroup-name)
      t)))

(defun gnus-set-global-variables ()
  "Set the global equivalents of the buffer-local variables.
They are set to the latest values they had.  These reflect the summary
buffer that was in action when the last article was fetched."
  (when (eq major-mode 'gnus-summary-mode)
    (setq gnus-summary-buffer (current-buffer))
    (let ((name gnus-newsgroup-name)
          (marked gnus-newsgroup-marked)
          (spam gnus-newsgroup-spam-marked)
          (unread gnus-newsgroup-unreads)
          (headers gnus-current-headers)
          (data gnus-newsgroup-data)
          (summary gnus-summary-buffer)
          (article-buffer gnus-article-buffer)
          (original gnus-original-article-buffer)
          (gac gnus-article-current)
          (reffed gnus-reffed-article-number)
          (score-file gnus-current-score-file)
          (default-charset gnus-newsgroup-charset)
          vlist)
      (let ((locals gnus-newsgroup-variables))
        (while locals
          (if (consp (car locals))
              (push (eval (caar locals)) vlist)
            (push (eval (car locals)) vlist))
          (setq locals (cdr locals)))
        (setq vlist (nreverse vlist)))
      (with-current-buffer gnus-group-buffer
        (setq gnus-newsgroup-name name
              gnus-newsgroup-marked marked
              gnus-newsgroup-spam-marked spam
              gnus-newsgroup-unreads unread
              gnus-current-headers headers
              gnus-newsgroup-data data
              gnus-article-current gac
              gnus-summary-buffer summary
              gnus-article-buffer article-buffer
              gnus-original-article-buffer original
              gnus-reffed-article-number reffed
              gnus-current-score-file score-file
              gnus-newsgroup-charset default-charset)
        (let ((locals gnus-newsgroup-variables))
          (while locals
            (if (consp (car locals))
                (set (caar locals) (pop vlist))
              (set (car locals) (pop vlist)))
            (setq locals (cdr locals))))
        ;; The article buffer also has local variables.
        (when (gnus-buffer-live-p gnus-article-buffer)
          (set-buffer gnus-article-buffer)
          (setq gnus-summary-buffer summary))))))

(defun gnus-summary-article-unread-p (article)
  "Say whether ARTICLE is unread or not."
  (memq article gnus-newsgroup-unreads))

(defun gnus-summary-first-article-p (&optional article)
  "Return whether ARTICLE is the first article in the buffer."
  (if (not (setq article (or article (gnus-summary-article-number))))
      nil
    (eq article (caar gnus-newsgroup-data))))

(defun gnus-summary-last-article-p (&optional article)
  "Return whether ARTICLE is the last article in the buffer."
  (if (not (setq article (or article (gnus-summary-article-number))))
      ;; All non-existent numbers are the last article.  :-)
      t
    (not (cdr (gnus-data-find-list article)))))

(defun gnus-make-thread-indent-array (&optional n)
  (when (or n
            (progn (setq n 200) nil)
            (null gnus-thread-indent-array)
            (/= gnus-thread-indent-level gnus-thread-indent-array-level))
    (setq gnus-thread-indent-array (make-vector (1+ n) "")
          gnus-thread-indent-array-level gnus-thread-indent-level)
    (while (>= n 0)
      (aset gnus-thread-indent-array n
            (make-string (* n gnus-thread-indent-level) ? ))
      (setq n (1- n)))))

(defun gnus-update-summary-mark-positions ()
  "Compute where the summary marks are to go."
  (save-excursion
    (when (gnus-buffer-exists-p gnus-summary-buffer)
      (set-buffer gnus-summary-buffer))
    (let ((spec gnus-summary-line-format-spec)
          pos)
      (save-excursion
        (gnus-set-work-buffer)
        (let ((gnus-tmp-unread ?Z)
              (gnus-replied-mark ?Z)
              (gnus-score-below-mark ?Z)
              (gnus-score-over-mark ?Z)
              (gnus-undownloaded-mark ?Z)
              (gnus-summary-line-format-spec spec)
              (gnus-newsgroup-downloadable '(0))
              (header [0 "" "" "05 Apr 2001 23:33:09 +0400" "" "" 0 0 "" nil])
              case-fold-search ignores)
          ;; Here, all marks are bound to Z.
          (gnus-summary-insert-line header
                                    0 nil t gnus-tmp-unread t nil "" nil 1)
          (goto-char (point-min))
          ;; Memorize the positions of the same characters as dummy marks.
          (while (re-search-forward "[A-D]" nil t)
            (push (point) ignores))
          (erase-buffer)
          ;; We use A-D as dummy marks in order to know column positions
          ;; where marks should be inserted.
          (setq gnus-tmp-unread ?A
                gnus-replied-mark ?B
                gnus-score-below-mark ?C
                gnus-score-over-mark ?C
                gnus-undownloaded-mark ?D)
          (gnus-summary-insert-line header
                                    0 nil t gnus-tmp-unread t nil "" nil 1)
          ;; Ignore characters which aren't dummy marks.
          (dolist (p ignores)
            (delete-region (goto-char (1- p)) p)
            (insert ?Z))
          (goto-char (point-min))
          (setq pos (list (cons 'unread
                                (and (search-forward "A" nil t)
                                     (- (point) (point-min) 1)))))
          (goto-char (point-min))
          (push (cons 'replied (and (search-forward "B" nil t)
                                    (- (point) (point-min) 1)))
                pos)
          (goto-char (point-min))
          (push (cons 'score (and (search-forward "C" nil t)
                                  (- (point) (point-min) 1)))
                pos)
          (goto-char (point-min))
          (push (cons 'download (and (search-forward "D" nil t)
                                     (- (point) (point-min) 1)))
                pos)))
      (setq gnus-summary-mark-positions pos))))

(defun gnus-summary-insert-dummy-line (gnus-tmp-subject gnus-tmp-number)
  "Insert a dummy root in the summary buffer."
  (beginning-of-line)
  (gnus-add-text-properties
   (point) (progn (eval gnus-summary-dummy-line-format-spec) (point))
   (list 'gnus-number gnus-tmp-number 'gnus-intangible gnus-tmp-number)))

(defun gnus-summary-extract-address-component (from)
  (or (car (funcall gnus-extract-address-components from))
      from))

(defun gnus-summary-from-or-to-or-newsgroups (header gnus-tmp-from)
  (let ((mail-parse-charset gnus-newsgroup-charset)
        (ignored-from-addresses (gnus-ignored-from-addresses))
        ; Is it really necessary to do this next part for each summary line?
        ; Luckily, doesn't seem to slow things down much.
        (mail-parse-ignored-charsets
         (with-current-buffer gnus-summary-buffer
           gnus-newsgroup-ignored-charsets)))
    (or
     (and ignored-from-addresses
          (string-match ignored-from-addresses gnus-tmp-from)
          (let ((extra-headers (mail-header-extra header))
                to
                newsgroups)
            (cond
             ((setq to (cdr (assq 'To extra-headers)))
              (concat gnus-summary-to-prefix
                      (inline
                        (gnus-summary-extract-address-component
                         (funcall gnus-decode-encoded-address-function to)))))
             ((setq newsgroups
                    (or
                     (cdr (assq 'Newsgroups extra-headers))
                     (and
                      (memq 'Newsgroups gnus-extra-headers)
                      (eq (car (gnus-find-method-for-group
                                gnus-newsgroup-name)) 'nntp)
                      (gnus-group-real-name gnus-newsgroup-name))))
              (concat gnus-summary-newsgroup-prefix newsgroups)))))
     (gnus-string-mark-left-to-right
      (inline
       (gnus-summary-extract-address-component gnus-tmp-from))))))

(defun gnus-summary-insert-line (gnus-tmp-header
                                 gnus-tmp-level gnus-tmp-current
                                 undownloaded gnus-tmp-unread gnus-tmp-replied
                                 gnus-tmp-expirable gnus-tmp-subject-or-nil
                                 &optional gnus-tmp-dummy gnus-tmp-score
                                 gnus-tmp-process)
  (if (>= gnus-tmp-level (length gnus-thread-indent-array))
      (gnus-make-thread-indent-array (max (* 2 (length gnus-thread-indent-array))
                                          gnus-tmp-level)))
  (let* ((gnus-tmp-indentation (aref gnus-thread-indent-array gnus-tmp-level))
         (gnus-tmp-lines (mail-header-lines gnus-tmp-header))
         (gnus-tmp-score (or gnus-tmp-score gnus-summary-default-score 0))
         (gnus-tmp-score-char
          (if (or (null gnus-summary-default-score)
                  (<= (abs (- gnus-tmp-score gnus-summary-default-score))
                      gnus-summary-zcore-fuzz))
              ?                         ;Whitespace
            (if (< gnus-tmp-score gnus-summary-default-score)
                gnus-score-below-mark gnus-score-over-mark)))
         (gnus-tmp-number (mail-header-number gnus-tmp-header))
         (gnus-tmp-replied
          (cond (gnus-tmp-process gnus-process-mark)
                ((memq gnus-tmp-current gnus-newsgroup-cached)
                 gnus-cached-mark)
                (gnus-tmp-replied gnus-replied-mark)
                ((memq gnus-tmp-current gnus-newsgroup-forwarded)
                 gnus-forwarded-mark)
                ((memq gnus-tmp-current gnus-newsgroup-saved)
                 gnus-saved-mark)
                ((memq gnus-tmp-number gnus-newsgroup-unseen)
                 gnus-unseen-mark)
                (t gnus-no-mark)))
         (gnus-tmp-downloaded
          (cond (undownloaded
                 gnus-undownloaded-mark)
                (gnus-newsgroup-agentized
                 gnus-downloaded-mark)
                (t
                 gnus-no-mark)))
         (gnus-tmp-from (mail-header-from gnus-tmp-header))
         (gnus-tmp-name
          (cond
           ((string-match "<[^>]+> *$" gnus-tmp-from)
            (let ((beg (match-beginning 0)))
              (or (and (string-match "^\".+\"" gnus-tmp-from)
                       (substring gnus-tmp-from 1 (1- (match-end 0))))
                  (substring gnus-tmp-from 0 beg))))
           ((string-match "(.+)" gnus-tmp-from)
            (substring gnus-tmp-from
                       (1+ (match-beginning 0)) (1- (match-end 0))))
           (t gnus-tmp-from)))
         (gnus-tmp-subject (mail-header-subject gnus-tmp-header))
         (gnus-tmp-opening-bracket (if gnus-tmp-dummy ?\< ?\[))
         (gnus-tmp-closing-bracket (if gnus-tmp-dummy ?\> ?\]))
         (inhibit-read-only t))
    (when (string= gnus-tmp-name "")
      (setq gnus-tmp-name gnus-tmp-from))
    (unless (numberp gnus-tmp-lines)
      (setq gnus-tmp-lines -1))
    (if (= gnus-tmp-lines -1)
        (setq gnus-tmp-lines "?")
      (setq gnus-tmp-lines (number-to-string gnus-tmp-lines)))
    (condition-case ()
        (gnus-put-text-property
         (point)
         (progn (eval gnus-summary-line-format-spec) (point))
         'gnus-number gnus-tmp-number)
      (error (gnus-message 5 "Error updating the summary line")))
    (when (gnus-visual-p 'summary-highlight 'highlight)
      (forward-line -1)
      (gnus-summary-highlight-line)
      (gnus-run-hooks 'gnus-summary-update-hook)
      (forward-line 1))))

(defun gnus-summary-update-line (&optional dont-update)
  "Update summary line after change."
  (when (and gnus-summary-default-score
             (not gnus-summary-inhibit-highlight))
    (let* ((gnus-summary-inhibit-highlight t) ; Prevent recursion.
           (article (gnus-summary-article-number))
           (score (gnus-summary-article-score article)))
      (unless dont-update
        (if (and gnus-summary-mark-below
                 (< (gnus-summary-article-score)
                    gnus-summary-mark-below))
            ;; This article has a low score, so we mark it as read.
            (when (memq article gnus-newsgroup-unreads)
              (gnus-summary-mark-article-as-read gnus-low-score-mark))
          (when (eq (gnus-summary-article-mark) gnus-low-score-mark)
            ;; This article was previously marked as read on account
            ;; of a low score, but now it has risen, so we mark it as
            ;; unread.
            (gnus-summary-mark-article-as-unread gnus-unread-mark)))
        (gnus-summary-update-mark
         (if (or (null gnus-summary-default-score)
                 (<= (abs (- score gnus-summary-default-score))
                     gnus-summary-zcore-fuzz))
             ?                          ;Whitespace
           (if (< score gnus-summary-default-score)
               gnus-score-below-mark gnus-score-over-mark))
         'score))
      ;; Do visual highlighting.
      (when (gnus-visual-p 'summary-highlight 'highlight)
        (gnus-summary-highlight-line)
        (gnus-run-hooks 'gnus-summary-update-hook)))))

(defvar gnus-tmp-new-adopts nil)

(defun gnus-summary-number-of-articles-in-thread (thread &optional level char)
  "Return the number of articles in THREAD.
This may be 0 in some cases -- if none of the articles in
the thread are to be displayed."
  (let* ((number
         ;; Fix by Luc Van Eycken <Luc.VanEycken@esat.kuleuven.ac.be>.
          (cond
           ((not (listp thread))
            1)
           ((and (consp thread) (cdr thread))
            (apply
             '+ 1 (mapcar
                   'gnus-summary-number-of-articles-in-thread (cdr thread))))
           ((null thread)
            1)
           ((memq (mail-header-number (car thread)) gnus-newsgroup-limit)
            1)
           (t 0))))
    (when (and level (zerop level) gnus-tmp-new-adopts)
      (incf number
            (apply '+ (mapcar
                       'gnus-summary-number-of-articles-in-thread
                       gnus-tmp-new-adopts))))
    (if char
        (if (> number 1) gnus-not-empty-thread-mark
          gnus-empty-thread-mark)
      number)))

(defsubst gnus-summary-line-message-size (head)
  "Return pretty-printed version of message size.
This function is intended to be used in
`gnus-summary-line-format-alist'."
  (let ((c (or (mail-header-chars head) -1)))
    (cond ((< c 0) "n/a")               ; chars not available
          ((< c (* 1000 10)) (format "%1.1fk" (/ c 1024.0)))
          ((< c (* 1000 100)) (format "%dk" (/ c 1024.0)))
          ((< c (* 1000 10000)) (format "%1.1fM" (/ c (* 1024.0 1024))))
          (t (format "%dM" (/ c (* 1024.0 1024)))))))

(defcustom gnus-user-date-format-alist
  '(((gnus-seconds-today) . "Today, %H:%M")
    ((+ 86400 (gnus-seconds-today)) . "Yesterday, %H:%M")
    (604800 . "%A %H:%M")               ; That's one week
    ((gnus-seconds-month) . "%A %d")
    ((gnus-seconds-year) . "%B %d")
    (t . "%b %d %Y"))                   ; This one is used when no other
                                        ; does match
  "Specifies date format depending on age of article.
This is an alist of items (AGE . FORMAT).  AGE can be a number (of
seconds) or a Lisp expression evaluating to a number.  When the age of
the article is less than this number, then use `format-time-string'
with the corresponding FORMAT for displaying the date of the article.
If AGE is not a number or a Lisp expression evaluating to a
non-number, then the corresponding FORMAT is used as a default value.

Note that the list is processed from the beginning, so it should be
sorted by ascending AGE.  Also note that items following the first
non-number AGE will be ignored.

You can use the functions `gnus-seconds-today', `gnus-seconds-month'
and `gnus-seconds-year' in the AGE spec.  They return the number of
seconds passed since the start of today, of this month, of this year,
respectively."
  :version "24.1"
  :group 'gnus-summary-format
  :type '(alist :key-type sexp :value-type string))

(defun gnus-user-date (messy-date)
  "Format the messy-date according to `gnus-user-date-format-alist'.
Returns \"  ?  \" if there's bad input or if another error occurs.
Input should look like this: \"Sun, 14 Oct 2001 13:34:39 +0200\"."
  (condition-case ()
      (let* ((messy-date (gnus-float-time (gnus-date-get-time messy-date)))
             (now (gnus-float-time))
             ;;If we don't find something suitable we'll use this one
             (my-format "%b %d '%y"))
        (let* ((difference (- now messy-date))
               (templist gnus-user-date-format-alist)
               (top (eval (caar templist))))
          (while (if (numberp top) (< top difference) (not top))
            (progn
              (setq templist (cdr templist))
              (setq top (eval (caar templist)))))
          (if (stringp (cdr (car templist)))
              (setq my-format (cdr (car templist)))))
        (format-time-string (eval my-format) (seconds-to-time messy-date)))
    (error "  ?   ")))

(defun gnus-summary-set-local-parameters (group)
  "Go through the local params of GROUP and set all variable specs in that list."
  (let ((vars '(quit-config active)))   ; Ignore things that aren't
                                        ; really variables.
    (dolist (elem (gnus-group-find-parameter group))
      (and (consp elem)                 ; Has to be a cons.
           (consp (cdr elem))           ; The cdr has to be a list.
           (symbolp (car elem))         ; Has to be a symbol in there.
           (not (memq (car elem) vars))
           (ignore-errors
             (push (car elem) vars)
             ;; Variables like `gnus-show-threads' that are globally
             ;; bound, if used as group parameters, need to get to be
             ;; buffer-local, whereas just parameters like `gcc-self',
             ;; `timestamp', etc. should not be bound as variables.
             (if (boundp (car elem))
                 (set (make-local-variable (car elem)) (eval (nth 1 elem)))
               (eval (nth 1 elem))))))))

(defun gnus-summary-read-group (group &optional show-all no-article
                                      kill-buffer no-display backward
                                      select-articles)
  "Start reading news in newsgroup GROUP.
If SHOW-ALL is non-nil, already read articles are also listed.
If NO-ARTICLE is non-nil, no article is selected initially.
If NO-DISPLAY, don't generate the summary buffer contents.
If KILL-BUFFER, it should be a buffer that's killed once the new
summary buffer has been generated.
If BACKWARD, move point to the previous group in the group buffer
If SELECT-ARTICLES, only select those articles from GROUP."
  (let (result)
    (while (and group
                (null (setq result
                            (let ((gnus-auto-select-next nil))
                              (or (gnus-summary-read-group-1
                                   group show-all no-article
                                   kill-buffer no-display
                                   select-articles)
                                  (setq show-all nil
                                        select-articles nil)))))
                (eq gnus-auto-select-next 'quietly))
      (set-buffer gnus-group-buffer)
      ;; The entry function called above goes to the next
      ;; group automatically, so we go two groups back
      ;; if we are searching for the previous group.
      (when backward
        (gnus-group-prev-unread-group 2))
      (if (not (equal group (gnus-group-group-name)))
          (setq group (gnus-group-group-name))
        (setq group nil)))
    result))

(defun gnus-summary-read-group-1 (group show-all no-article
                                        kill-buffer no-display
                                        &optional select-articles)
  ;; Killed foreign groups can't be entered.
  ;;  (when (and (not (gnus-group-native-p group))
  ;;         (not (gnus-gethash group gnus-newsrc-hashtb)))
  ;;    (error "Dead non-native groups can't be entered"))
  (gnus-message 7 "Retrieving newsgroup: %s..."
                (gnus-group-decoded-name group))
  (let* ((new-group (gnus-summary-setup-buffer group))
         (quit-config (gnus-group-quit-config group))
         (did-select (and new-group (gnus-select-newsgroup
                                     group show-all select-articles))))
    (cond
     ;; This summary buffer exists already, so we just select it.
     ((not new-group)
      (gnus-set-global-variables)
      (when kill-buffer
        (gnus-kill-or-deaden-summary kill-buffer))
      (gnus-configure-windows 'summary 'force)
      (gnus-set-mode-line 'summary)
      (gnus-summary-position-point)
      (message "")
      t)
     ;; We couldn't select this group.
     ((null did-select)
      (when (and (eq major-mode 'gnus-summary-mode)
                 (not (equal (current-buffer) kill-buffer)))
        (kill-buffer (current-buffer))
        (if (not quit-config)
            (progn
              ;; Update the info -- marks might need to be removed,
              ;; for instance.
              (gnus-summary-update-info)
              (set-buffer gnus-group-buffer)
              (gnus-group-jump-to-group group)
              (gnus-group-next-unread-group 1))
          (gnus-handle-ephemeral-exit quit-config)))
      (if (null (gnus-list-of-unread-articles group))
          (gnus-message 3 "Group %s contains no messages" group)
        (gnus-message 3 "Can't select group"))
      nil)
     ;; The user did a `C-g' while prompting for number of articles,
     ;; so we exit this group.
     ((eq did-select 'quit)
      (and (eq major-mode 'gnus-summary-mode)
           (not (equal (current-buffer) kill-buffer))
           (kill-buffer (current-buffer)))
      (when kill-buffer
        (gnus-kill-or-deaden-summary kill-buffer))
      (if (not quit-config)
          (progn
            (set-buffer gnus-group-buffer)
            (gnus-group-jump-to-group group)
            (gnus-configure-windows 'group 'force))
        (gnus-handle-ephemeral-exit quit-config))
      ;; Finally signal the quit.
      (signal 'quit nil))
     ;; The group was successfully selected.
     (t
      (gnus-set-global-variables)
      ;; Save the active value in effect when the group was entered.
      (setq gnus-newsgroup-active
            (gnus-copy-sequence
             (gnus-active gnus-newsgroup-name)))
      (setq gnus-newsgroup-highest (cdr gnus-newsgroup-active))
      ;; You can change the summary buffer in some way with this hook.
      (gnus-run-hooks 'gnus-select-group-hook)
      (when (memq 'summary (gnus-update-format-specifications
                            nil 'summary 'summary-mode 'summary-dummy))
        ;; The format specification for the summary line was updated,
        ;; so we need to update the mark positions as well.
        (gnus-update-summary-mark-positions))
      ;; Do score processing.
      (when gnus-use-scoring
        (gnus-possibly-score-headers))
      ;; Check whether to fill in the gaps in the threads.
      (when gnus-build-sparse-threads
        (gnus-build-sparse-threads))
      ;; Find the initial limit.
      (if show-all
          (let ((gnus-newsgroup-dormant nil))
            (gnus-summary-initial-limit show-all))
        (gnus-summary-initial-limit show-all))
      ;; Generate the summary buffer.
      (unless no-display
        (gnus-summary-prepare))
      (when gnus-use-trees
        (gnus-tree-open group)
        (setq gnus-summary-highlight-line-function
              'gnus-tree-highlight-article))
      ;; If the summary buffer is empty, but there are some low-scored
      ;; articles or some excluded dormants, we include these in the
      ;; buffer.
      (when (and (zerop (buffer-size))
                 (not no-display))
        (cond (gnus-newsgroup-dormant
               (gnus-summary-limit-include-dormant))
              ((and gnus-newsgroup-scored show-all)
               (gnus-summary-limit-include-expunged t))))
      ;; Function `gnus-apply-kill-file' must be called in this hook.
      (gnus-run-hooks 'gnus-apply-kill-hook)
      (if (and (zerop (buffer-size))
               (not no-display))
          (progn
            ;; This newsgroup is empty.
            (gnus-summary-catchup-and-exit nil t)
            (gnus-message 6 "No unread news")
            (when kill-buffer
              (gnus-kill-or-deaden-summary kill-buffer))
            ;; Return nil from this function.
            nil)
        ;; Hide conversation thread subtrees.  We cannot do this in
        ;; gnus-summary-prepare-hook since kill processing may not
        ;; work with hidden articles.
        (gnus-summary-maybe-hide-threads)
        (gnus-configure-windows 'summary)
        (when kill-buffer
          (gnus-kill-or-deaden-summary kill-buffer))
        (gnus-summary-auto-select-subject)
        ;; Show first unread article if requested.
        (if (and (not no-article)
                 (not no-display)
                 gnus-newsgroup-unreads
                 gnus-auto-select-first)
            (progn
              (let ((art (gnus-summary-article-number)))
                (unless (and (not gnus-plugged)
                             (or (memq art gnus-newsgroup-undownloaded)
                                 (memq art gnus-newsgroup-downloadable)))
                  (gnus-summary-goto-article art))))
          ;; Don't select any articles.
          (gnus-summary-position-point)
          (gnus-configure-windows 'summary 'force)
          (gnus-set-mode-line 'summary))
        (when (and gnus-auto-center-group
                   (get-buffer-window gnus-group-buffer t))
          ;; Gotta use windows, because recenter does weird stuff if
          ;; the current buffer ain't the displayed window.
          (let ((owin (selected-window)))
            (select-window (get-buffer-window gnus-group-buffer t))
            (when (gnus-group-goto-group group)
              (recenter))
            (select-window owin)))
        ;; Mark this buffer as "prepared".
        (setq gnus-newsgroup-prepared t)
        (gnus-run-hooks 'gnus-summary-prepared-hook)
        (unless (gnus-ephemeral-group-p group)
          (gnus-group-update-group group nil t))
        t)))))

(defun gnus-summary-auto-select-subject ()
  "Select the subject line on initial group entry."
  (goto-char (point-min))
  (cond
   ((eq gnus-auto-select-subject 'best)
    (gnus-summary-best-unread-subject))
   ((eq gnus-auto-select-subject 'unread)
    (gnus-summary-first-unread-subject))
   ((eq gnus-auto-select-subject 'unseen)
    (gnus-summary-first-unseen-subject))
   ((eq gnus-auto-select-subject 'unseen-or-unread)
    (gnus-summary-first-unseen-or-unread-subject))
   ((eq gnus-auto-select-subject 'first)
    ;; Do nothing.
    )
   ((functionp gnus-auto-select-subject)
    (funcall gnus-auto-select-subject))))

(defun gnus-summary-prepare ()
  "Generate the summary buffer."
  (interactive)
  (let ((inhibit-read-only t))
    (erase-buffer)
    (setq gnus-newsgroup-data nil
          gnus-newsgroup-data-reverse nil)
    (gnus-run-hooks 'gnus-summary-generate-hook)
    ;; Generate the buffer, either with threads or without.
    (when gnus-newsgroup-headers
      (gnus-summary-prepare-threads
       (if gnus-show-threads
           (gnus-sort-gathered-threads
            (funcall gnus-summary-thread-gathering-function
                     (gnus-sort-threads
                      (gnus-cut-threads (gnus-make-threads)))))
         ;; Unthreaded display.
         (gnus-sort-articles gnus-newsgroup-headers))))
    (setq gnus-newsgroup-data (nreverse gnus-newsgroup-data))
    ;; Call hooks for modifying summary buffer.
    (goto-char (point-min))
    (gnus-run-hooks 'gnus-summary-prepare-hook)))

(defsubst gnus-general-simplify-subject (subject)
  "Simplify subject by the same rules as `gnus-gather-threads-by-subject'."
  (setq subject
        (cond
         ;; Truncate the subject.
         (gnus-simplify-subject-functions
          (gnus-map-function gnus-simplify-subject-functions subject))
         ((numberp gnus-summary-gather-subject-limit)
          (setq subject (gnus-simplify-subject-re subject))
          (if (> (length subject) gnus-summary-gather-subject-limit)
              (substring subject 0 gnus-summary-gather-subject-limit)
            subject))
         ;; Fuzzily simplify it.
         ((eq 'fuzzy gnus-summary-gather-subject-limit)
          (gnus-simplify-subject-fuzzy subject))
         ;; Just remove the leading "Re:".
         (t
          (gnus-simplify-subject-re subject))))

  (if (and gnus-summary-gather-exclude-subject
           (string-match gnus-summary-gather-exclude-subject subject))
      nil                         ; This article shouldn't be gathered
    subject))

(defun gnus-summary-simplify-subject-query ()
  "Query where the respool algorithm would put this article."
  (interactive)
  (gnus-summary-select-article)
  (message "%s" (gnus-general-simplify-subject (gnus-summary-article-subject))))

(defun gnus-gather-threads-by-subject (threads)
  "Gather threads by looking at Subject headers."
  (if (not gnus-summary-make-false-root)
      threads
    (let ((hashtb (gnus-make-hashtable 1024))
          (prev threads)
          (result threads)
          subject hthread whole-subject)
      (while threads
        (setq subject (gnus-general-simplify-subject
                       (setq whole-subject (mail-header-subject
                                            (caar threads)))))
        (when subject
          (if (setq hthread (gnus-gethash subject hashtb))
              (progn
                ;; We enter a dummy root into the thread, if we
                ;; haven't done that already.
                (unless (stringp (caar hthread))
                  (setcar hthread (list whole-subject (car hthread))))
                ;; We add this new gathered thread to this gathered
                ;; thread.
                (setcdr (car hthread)
                        (nconc (cdar hthread) (list (car threads))))
                ;; Remove it from the list of threads.
                (setcdr prev (cdr threads))
                (setq threads prev))
            ;; Enter this thread into the hash table.
            (gnus-sethash subject
                          (if gnus-summary-make-false-root-always
                              (progn
                                ;; If you want a dummy root above all
                                ;; threads...
                                (setcar threads (list whole-subject
                                                      (car threads)))
                                threads)
                            threads)
                          hashtb)))
        (setq prev threads)
        (setq threads (cdr threads)))
      result)))

(defun gnus-gather-threads-by-references (threads)
  "Gather threads by looking at References headers."
  (let ((idhashtb (gnus-make-hashtable 1024))
        (thhashtb (gnus-make-hashtable 1024))
        (prev threads)
        (result threads)
        ids references id gthread gid entered ref)
    (while threads
      (when (setq references (mail-header-references (caar threads)))
        (setq id (mail-header-id (caar threads))
              ids (inline (gnus-split-references references))
              entered nil)
        (while (setq ref (pop ids))
          (setq ids (delete ref ids))
          (if (not (setq gid (gnus-gethash ref idhashtb)))
              (progn
                (gnus-sethash ref id idhashtb)
                (gnus-sethash id threads thhashtb))
            (setq gthread (gnus-gethash gid thhashtb))
            (unless entered
              ;; We enter a dummy root into the thread, if we
              ;; haven't done that already.
              (unless (stringp (caar gthread))
                (setcar gthread (list (mail-header-subject (caar gthread))
                                      (car gthread))))
              ;; We add this new gathered thread to this gathered
              ;; thread.
              (setcdr (car gthread)
                      (nconc (cdar gthread) (list (car threads)))))
            ;; Add it into the thread hash table.
            (gnus-sethash id gthread thhashtb)
            (setq entered t)
            ;; Remove it from the list of threads.
            (setcdr prev (cdr threads))
            (setq threads prev))))
      (setq prev threads)
      (setq threads (cdr threads)))
    result))

(defun gnus-sort-gathered-threads (threads)
  "Sort subthreads inside each gathered thread by `gnus-sort-gathered-threads-function'."
  (let ((result threads))
    (while threads
      (when (stringp (caar threads))
        (setcdr (car threads)
                (sort (cdar threads) gnus-sort-gathered-threads-function)))
      (setq threads (cdr threads)))
    result))

(defun gnus-thread-loop-p (root thread)
  "Say whether ROOT is in THREAD."
  (let ((stack (list thread))
        (infloop 0)
        th)
    (while (setq thread (pop stack))
      (setq th (cdr thread))
      (while (and th
                  (not (eq (caar th) root)))
        (pop th))
      (if th
          ;; We have found a loop.
          (let (ref-dep)
            (setcdr thread (delq (car th) (cdr thread)))
            (if (boundp (setq ref-dep (intern "none"
                                              gnus-newsgroup-dependencies)))
                (setcdr (symbol-value ref-dep)
                        (nconc (cdr (symbol-value ref-dep))
                               (list (car th))))
              (set ref-dep (list nil (car th))))
            (setq infloop 1
                  stack nil))
        ;; Push all the subthreads onto the stack.
        (push (cdr thread) stack)))
    infloop))

(defun gnus-make-threads ()
  "Go through the dependency hashtb and find the roots.  Return all threads."
  (let (threads)
    (while (catch 'infloop
             (mapatoms
              (lambda (refs)
                ;; Deal with self-referencing References loops.
                (when (and (car (symbol-value refs))
                           (not (zerop
                                 (apply
                                  '+
                                  (mapcar
                                   (lambda (thread)
                                     (gnus-thread-loop-p
                                      (car (symbol-value refs)) thread))
                                   (cdr (symbol-value refs)))))))
                  (setq threads nil)
                  (throw 'infloop t))
                (unless (car (symbol-value refs))
                  ;; These threads do not refer back to any other
                  ;; articles, so they're roots.
                  (setq threads (append (cdr (symbol-value refs)) threads))))
              gnus-newsgroup-dependencies)))
    threads))

;; Build the thread tree.
(defsubst gnus-dependencies-add-header (header dependencies force-new)
  "Enter HEADER into the DEPENDENCIES table if it is not already there.

If FORCE-NEW is not nil, enter HEADER into the DEPENDENCIES table even
if it was already present.

If `gnus-summary-ignore-duplicates' is nil then duplicate Message-IDs
will not be entered in the DEPENDENCIES table.  Otherwise duplicate
Message-IDs will be renamed to a unique Message-ID before being
entered.

Returns HEADER if it was entered in the DEPENDENCIES.  Returns nil otherwise."
  (let* ((id (mail-header-id header))
         (id-dep (and id (intern id dependencies)))
         parent-id ref ref-dep ref-header replaced)
    ;; Enter this `header' in the `dependencies' table.
    (cond
     ((not id-dep)
      (setq header nil))
     ;; The first two cases do the normal part: enter a new `header'
     ;; in the `dependencies' table.
     ((not (boundp id-dep))
      (set id-dep (list header)))
     ((null (car (symbol-value id-dep)))
      (setcar (symbol-value id-dep) header))

     ;; From here the `header' was already present in the
     ;; `dependencies' table.
     (force-new
      ;; Overrides an existing entry;
      ;; just set the header part of the entry.
      (setcar (symbol-value id-dep) header)
      (setq replaced t))

     ;; Renames the existing `header' to a unique Message-ID.
     ((not gnus-summary-ignore-duplicates)
      ;; An article with this Message-ID has already been seen.
      ;; We rename the Message-ID.
      (set (setq id-dep (intern (setq id (nnmail-message-id)) dependencies))
           (list header))
      (mail-header-set-id header id))

     ;; The last case ignores an existing entry, except it adds any
     ;; additional Xrefs (in case the two articles came from different
     ;; servers.
     ;; Also sets `header' to `nil' meaning that the `dependencies'
     ;; table was *not* modified.
     (t
      (mail-header-set-xref
       (car (symbol-value id-dep))
       (concat (or (mail-header-xref (car (symbol-value id-dep)))
                   "")
               (or (mail-header-xref header) "")))
      (setq header nil)))

    (when (and header (not replaced))
      ;; First check that we are not creating a References loop.
      (setq parent-id (gnus-parent-id (mail-header-references header)))
      (setq ref parent-id)
      (while (and ref
                  (setq ref-dep (intern-soft ref dependencies))
                  (boundp ref-dep)
                  (setq ref-header (car (symbol-value ref-dep))))
        (if (string= id ref)
            ;; Yuk!  This is a reference loop.  Make the article be a
            ;; root article.
            (progn
              (mail-header-set-references (car (symbol-value id-dep)) "none")
              (setq ref nil)
              (setq parent-id nil))
          (setq ref (gnus-parent-id (mail-header-references ref-header)))))
      (setq ref-dep (intern (or parent-id "none") dependencies))
      (if (boundp ref-dep)
          (setcdr (symbol-value ref-dep)
                  (nconc (cdr (symbol-value ref-dep))
                         (list (symbol-value id-dep))))
        (set ref-dep (list nil (symbol-value id-dep)))))
    header))

(defun gnus-extract-message-id-from-in-reply-to (string)
  (if (string-match "<[^>]+>" string)
      (substring string (match-beginning 0) (match-end 0))
    nil))

(defun gnus-build-sparse-threads ()
  (let ((headers gnus-newsgroup-headers)
        (mail-parse-charset gnus-newsgroup-charset)
        (gnus-summary-ignore-duplicates t)
        header references generation relations
        subject child end new-child date)
    ;; First we create an alist of generations/relations, where
    ;; generations is how much we trust the relation, and the relation
    ;; is parent/child.
    (gnus-message 7 "Making sparse threads...")
    (save-excursion
      (nnheader-set-temp-buffer " *gnus sparse threads*")
      (while (setq header (pop headers))
        (when (and (setq references (mail-header-references header))
                   (not (string= references "")))
          (insert references)
          (setq child (mail-header-id header)
                subject (mail-header-subject header)
                date (mail-header-date header)
                generation 0)
          (while (search-backward ">" nil t)
            (setq end (1+ (point)))
            (when (search-backward "<" nil t)
              (setq new-child (buffer-substring (point) end))
              (push (list (incf generation)
                          child (setq child new-child)
                          subject date)
                    relations)))
          (when child
            (push (list (1+ generation) child nil subject) relations))
          (erase-buffer)))
      (kill-buffer (current-buffer)))
    ;; Sort over trustworthiness.
    (dolist (relation (sort relations 'car-less-than-car))
      (when (gnus-dependencies-add-header
             (make-full-mail-header
              gnus-reffed-article-number
              (nth 3 relation) "" (or (nth 4 relation) "")
              (nth 1 relation)
              (or (nth 2 relation) "") 0 0 "")
             gnus-newsgroup-dependencies nil)
        (push gnus-reffed-article-number gnus-newsgroup-limit)
        (push gnus-reffed-article-number gnus-newsgroup-sparse)
        (push (cons gnus-reffed-article-number gnus-sparse-mark)
              gnus-newsgroup-reads)
        (decf gnus-reffed-article-number)))
    (gnus-message 7 "Making sparse threads...done")))

(defun gnus-build-old-threads ()
  ;; Look at all the articles that refer back to old articles, and
  ;; fetch the headers for the articles that aren't there.  This will
  ;; build complete threads - if the roots haven't been expired by the
  ;; server, that is.
  (let ((mail-parse-charset gnus-newsgroup-charset)
        id heads)
    (mapatoms
     (lambda (refs)
       (when (not (car (symbol-value refs)))
         (setq heads (cdr (symbol-value refs)))
         (while heads
           (if (memq (mail-header-number (caar heads))
                     gnus-newsgroup-dormant)
               (setq heads (cdr heads))
             (setq id (symbol-name refs))
             (while (and (setq id (gnus-build-get-header id))
                         (not (car (gnus-id-to-thread id)))))
             (setq heads nil)))))
     gnus-newsgroup-dependencies)))

(defsubst gnus-remove-odd-characters (string)
  "Translate STRING into something that doesn't contain weird characters."
  (mm-subst-char-in-string
   ?\r ?\-
   (mm-subst-char-in-string ?\n ?\- string t) t))

;; This function has to be called with point after the article number
;; on the beginning of the line.
(defsubst gnus-nov-parse-line (number dependencies &optional force-new)
  (let ((eol (point-at-eol))
        (buffer (current-buffer))
        header references in-reply-to)

    ;; overview: [num subject from date id refs chars lines misc]
    (unwind-protect
        (let (x)
          (narrow-to-region (point) eol)
          (unless (eobp)
            (forward-char))

          (setq header
                (make-full-mail-header
                 number                 ; number
                 (condition-case ()     ; subject
                     (gnus-remove-odd-characters
                      (funcall gnus-decode-encoded-word-function
                               (setq x (nnheader-nov-field))))
                   (error x))
                 (condition-case ()     ; from
                     (gnus-remove-odd-characters
                      (funcall gnus-decode-encoded-address-function
                               (setq x (nnheader-nov-field))))
                   (error x))
                 (nnheader-nov-field)   ; date
                 (nnheader-nov-read-message-id number)  ; id
                 (setq references (nnheader-nov-field)) ; refs
                 (nnheader-nov-read-integer) ; chars
                 (nnheader-nov-read-integer) ; lines
                 (unless (eobp)
                   (if (looking-at "Xref: ")
                       (goto-char (match-end 0)))
                   (nnheader-nov-field)) ; Xref
                 (nnheader-nov-parse-extra)))) ; extra

      (widen))

    (when (and (string= references "")
               (setq in-reply-to (mail-header-extra header))
               (setq in-reply-to (cdr (assq 'In-Reply-To in-reply-to))))
      (mail-header-set-references
       header (gnus-extract-message-id-from-in-reply-to in-reply-to)))

    (when gnus-alter-header-function
      (funcall gnus-alter-header-function header))
    (gnus-dependencies-add-header header dependencies force-new)))

(defun gnus-build-get-header (id)
  "Look through the buffer of NOV lines and find the header to ID.
Enter this line into the dependencies hash table, and return
the id of the parent article (if any)."
  (let ((deps gnus-newsgroup-dependencies)
        found header)
    (prog1
        (with-current-buffer nntp-server-buffer
          (let ((case-fold-search nil))
            (goto-char (point-min))
            (while (and (not found)
                        (search-forward id nil t))
              (beginning-of-line)
              (setq found (looking-at
                           (format "^[^\t]*\t[^\t]*\t[^\t]*\t[^\t]*\t%s"
                                   (regexp-quote id))))
              (or found (beginning-of-line 2)))
            (when found
              (beginning-of-line)
              (and
               (setq header (gnus-nov-parse-line
                             (read (current-buffer)) deps))
               (gnus-parent-id (mail-header-references header))))))
      (when header
        (let ((number (mail-header-number header)))
          (push number gnus-newsgroup-limit)
          (push header gnus-newsgroup-headers)
          (if (memq number gnus-newsgroup-unselected)
              (progn
                (setq gnus-newsgroup-unreads
                      (gnus-add-to-sorted-list gnus-newsgroup-unreads
                                               number))
                (setq gnus-newsgroup-unselected
                      (delq number gnus-newsgroup-unselected)))
            (push number gnus-newsgroup-ancient)))))))

(defun gnus-build-all-threads ()
  "Read all the headers."
  (let ((gnus-summary-ignore-duplicates t)
        (mail-parse-charset gnus-newsgroup-charset)
        (dependencies gnus-newsgroup-dependencies)
        header article)
    (with-current-buffer nntp-server-buffer
      (let ((case-fold-search nil))
        (goto-char (point-min))
        (while (not (eobp))
          (ignore-errors
            (setq article (read (current-buffer))
                  header (gnus-nov-parse-line article dependencies t)))
          (when header
            (with-current-buffer gnus-summary-buffer
              (push header gnus-newsgroup-headers)
              (if (memq (setq article (mail-header-number header))
                        gnus-newsgroup-unselected)
                  (progn
                    (setq gnus-newsgroup-unreads
                          (gnus-add-to-sorted-list
                           gnus-newsgroup-unreads article))
                    (setq gnus-newsgroup-unselected
                          (delq article gnus-newsgroup-unselected)))
                (push article gnus-newsgroup-ancient)))
            (forward-line 1)))))))

(defun gnus-summary-update-article-line (article header)
  "Update the line for ARTICLE using HEADER."
  (let* ((id (mail-header-id header))
         (thread (gnus-id-to-thread id)))
    (unless thread
      (error "Article in no thread"))
    ;; Update the thread.
    (setcar thread header)
    (gnus-summary-goto-subject article)
    (let* ((datal (gnus-data-find-list article))
           (data (car datal))
           (inhibit-read-only t)
           (level (gnus-summary-thread-level)))
      (gnus-delete-line)
      (let ((inserted (- (point)
                         (progn
                           (gnus-summary-insert-line
                            header level nil
                            (memq article gnus-newsgroup-undownloaded)
                            (gnus-article-mark article)
                            (memq article gnus-newsgroup-replied)
                            (memq article gnus-newsgroup-expirable)
                            ;; Only insert the Subject string when it's different
                            ;; from the previous Subject string.
                            (if (and
                                 gnus-show-threads
                                 (gnus-subject-equal
                                  (condition-case ()
                                      (mail-header-subject
                                       (gnus-data-header
                                        (cadr
                                         (gnus-data-find-list
                                          article
                                          (gnus-data-list t)))))
                                    ;; Error on the side of excessive subjects.
                                    (error ""))
                                  (mail-header-subject header)))
                                ""
                              (mail-header-subject header))
                            nil (cdr (assq article gnus-newsgroup-scored))
                            (memq article gnus-newsgroup-processable))
                           (point)))))
        (when (cdr datal)
          (gnus-data-update-list
           (cdr datal)
           (- (gnus-data-pos data) (gnus-data-pos (cadr datal)) inserted)))))))

(defun gnus-summary-update-article (article &optional iheader)
  "Update ARTICLE in the summary buffer."
  (set-buffer gnus-summary-buffer)
  (let* ((header (gnus-summary-article-header article))
         (id (mail-header-id header))
         (data (gnus-data-find article))
         (thread (gnus-id-to-thread id))
         (references (mail-header-references header))
         (parent
          (gnus-id-to-thread
           (or (gnus-parent-id
                (when (and references
                           (not (equal "" references)))
                  references))
               "none")))
         (inhibit-read-only t)
         (old (car thread)))
    (when thread
      (unless iheader
        (setcar thread nil)
        (when parent
          (delq thread parent)))
      (if (gnus-summary-insert-subject id header)
          ;; Set the (possibly) new article number in the data structure.
          (gnus-data-set-number data (gnus-id-to-article id))
        (setcar thread old)
        nil))))

(defun gnus-rebuild-thread (id &optional line)
  "Rebuild the thread containing ID.
If LINE, insert the rebuilt thread starting on line LINE."
  (let ((inhibit-read-only t)
        old-pos current thread data)
    (if (not gnus-show-threads)
        (setq thread (list (car (gnus-id-to-thread id))))
      ;; Get the thread this article is part of.
      (setq thread (gnus-remove-thread id)))
    (setq old-pos (point-at-bol))
    (setq current (save-excursion
                    (and (re-search-backward "[\r\n]" nil t)
                         (gnus-summary-article-number))))
    ;; If this is a gathered thread, we have to go some re-gathering.
    (when (stringp (car thread))
      (let ((subject (car thread))
            roots thr)
        (setq thread (cdr thread))
        (while thread
          (unless (memq (setq thr (gnus-id-to-thread
                                   (gnus-root-id
                                    (mail-header-id (caar thread)))))
                        roots)
            (push thr roots))
          (setq thread (cdr thread)))
        ;; We now have all (unique) roots.
        (if (= (length roots) 1)
            ;; All the loose roots are now one solid root.
            (setq thread (car roots))
          (setq thread (cons subject (gnus-sort-threads roots))))))
    (let (threads)
      ;; We then insert this thread into the summary buffer.
      (when line
        (goto-char (point-min))
        (forward-line (1- line)))
      (let (gnus-newsgroup-data gnus-newsgroup-threads)
        (if gnus-show-threads
            (gnus-summary-prepare-threads (gnus-cut-threads (list thread)))
          (gnus-summary-prepare-unthreaded thread))
        (setq data (nreverse gnus-newsgroup-data))
        (setq threads gnus-newsgroup-threads))
      ;; We splice the new data into the data structure.
      ;;!!! This is kinda bogus.  We assume that in LINE is non-nil,
      ;;!!! then we want to insert at the beginning of the buffer.
      ;;!!! That happens to be true with Gnus now, but that may
      ;;!!! change in the future.  Perhaps.
      (gnus-data-enter-list
       (if line nil current) data (- (point) old-pos))
      (setq gnus-newsgroup-threads
            (nconc threads gnus-newsgroup-threads))
      (gnus-data-compute-positions))))

(defun gnus-number-to-header (number)
  "Return the header for article NUMBER."
  (let ((headers gnus-newsgroup-headers))
    (while (and headers
                (not (= number (mail-header-number (car headers)))))
      (pop headers))
    (when headers
      (car headers))))

(defun gnus-parent-headers (in-headers &optional generation)
  "Return the headers of the GENERATIONth parent of HEADERS."
  (unless generation
    (setq generation 1))
  (let ((parent t)
        (headers in-headers)
        references)
    (while (and parent
                (not (zerop generation))
                (setq references (mail-header-references headers)))
      (setq headers (if (and references
                             (setq parent (gnus-parent-id references)))
                        (car (gnus-id-to-thread parent))
                      nil))
      (decf generation))
    (and (not (eq headers in-headers))
         headers)))

(defun gnus-id-to-thread (id)
  "Return the (sub-)thread where ID appears."
  (gnus-gethash id gnus-newsgroup-dependencies))

(defun gnus-id-to-article (id)
  "Return the article number of ID."
  (let ((thread (gnus-id-to-thread id)))
    (when (and thread
               (car thread))
      (mail-header-number (car thread)))))

(defun gnus-id-to-header (id)
  "Return the article headers of ID."
  (car (gnus-id-to-thread id)))

(defun gnus-article-displayed-root-p (article)
  "Say whether ARTICLE is a root(ish) article."
  (let ((level (gnus-summary-thread-level article))
        (refs (mail-header-references  (gnus-summary-article-header article)))
        particle)
    (cond
     ((null level) nil)
     ((zerop level) t)
     ((null refs) t)
     ((null (gnus-parent-id refs)) t)
     ((and (= 1 level)
           (null (setq particle (gnus-id-to-article
                                 (gnus-parent-id refs))))
           (null (gnus-summary-thread-level particle)))))))

(defun gnus-root-id (id)
  "Return the id of the root of the thread where ID appears."
  (let (last-id prev)
    (while (and id (setq prev (car (gnus-id-to-thread id))))
      (setq last-id id
            id (gnus-parent-id (mail-header-references prev))))
    last-id))

(defun gnus-articles-in-thread (thread)
  "Return the list of articles in THREAD."
  (cons (mail-header-number (car thread))
        (apply 'nconc (mapcar 'gnus-articles-in-thread (cdr thread)))))

(defun gnus-remove-thread (id &optional dont-remove)
  "Remove the thread that has ID in it."
  (let (headers thread last-id)
    ;; First go up in this thread until we find the root.
    (setq last-id (gnus-root-id id)
          headers (message-flatten-list (gnus-id-to-thread last-id)))
    ;; We have now found the real root of this thread.  It might have
    ;; been gathered into some loose thread, so we have to search
    ;; through the threads to find the thread we wanted.
    (let ((threads gnus-newsgroup-threads)
          sub)
      (while threads
        (setq sub (car threads))
        (if (stringp (car sub))
            ;; This is a gathered thread, so we look at the roots
            ;; below it to find whether this article is in this
            ;; gathered root.
            (progn
              (setq sub (cdr sub))
              (while sub
                (when (member (caar sub) headers)
                  (setq thread (car threads)
                        threads nil
                        sub nil))
                (setq sub (cdr sub))))
          ;; It's an ordinary thread, so we check it.
          (when (eq (car sub) (car headers))
            (setq thread sub
                  threads nil)))
        (setq threads (cdr threads)))
      ;; If this article is in no thread, then it's a root.
      (if thread
          (unless dont-remove
            (setq gnus-newsgroup-threads (delq thread gnus-newsgroup-threads)))
        (setq thread (gnus-id-to-thread last-id)))
      (when thread
        (prog1
            thread                      ; We return this thread.
          (unless dont-remove
            (if (stringp (car thread))
                (progn
                  ;; If we use dummy roots, then we have to remove the
                  ;; dummy root as well.
                  (when (eq gnus-summary-make-false-root 'dummy)
                    ;; We go to the dummy root by going to
                    ;; the first sub-"thread", and then one line up.
                    (gnus-summary-goto-article
                     (mail-header-number (caadr thread)))
                    (forward-line -1)
                    (gnus-delete-line)
                    (gnus-data-compute-positions))
                  (setq thread (cdr thread))
                  (while thread
                    (gnus-remove-thread-1 (car thread))
                    (setq thread (cdr thread))))
              (gnus-remove-thread-1 thread))))))))

(defun gnus-remove-thread-1 (thread)
  "Remove the thread THREAD recursively."
  (let ((number (mail-header-number (pop thread)))
        d)
    (setq thread (reverse thread))
    (while thread
      (gnus-remove-thread-1 (pop thread)))
    (when (setq d (gnus-data-find number))
      (goto-char (gnus-data-pos d))
      (gnus-summary-show-thread)
      (gnus-data-remove
       number
       (- (point-at-bol)
          (prog1
              (1+ (point-at-eol))
            (gnus-delete-line)))))))

(defun gnus-sort-threads-recursive (threads func)
  (sort (mapcar (lambda (thread)
                  (cons (car thread)
                        (and (cdr thread)
                             (gnus-sort-threads-recursive (cdr thread) func))))
                threads) func))

(defun gnus-sort-threads-loop (threads func)
  (let* ((superthread (cons nil threads))
         (stack (list (cons superthread threads)))
         remaining-threads thread)
    (while stack
      (setq remaining-threads (cdr (car stack)))
      (if remaining-threads
          (progn (setq thread (car remaining-threads))
                 (setcdr (car stack) (cdr remaining-threads))
                 (if (cdr thread)
                     (push (cons thread (cdr thread)) stack)))
        (setq thread (caar stack))
        (setcdr thread (sort (cdr thread) func))
        (pop stack)))
    (cdr superthread)))

(defun gnus-sort-threads (threads)
  "Sort THREADS."
  (if (not gnus-thread-sort-functions)
      threads
    (gnus-message 8 "Sorting threads...")
    (prog1
        (condition-case nil
            (let ((max-lisp-eval-depth (max max-lisp-eval-depth 5000)))
              (gnus-sort-threads-recursive
               threads (gnus-make-sort-function gnus-thread-sort-functions)))
          ;; Even after binding max-lisp-eval-depth, the recursive
          ;; sorter might fail for very long threads.  In that case,
          ;; try using a (less well-tested) non-recursive sorter.
          (error (gnus-message 9 "Sorting threads with loop...")
                 (gnus-sort-threads-loop
                  threads (gnus-make-sort-function
                           gnus-thread-sort-functions))))
      (gnus-message 8 "Sorting threads...done"))))

(defun gnus-sort-articles (articles)
  "Sort ARTICLES."
  (when gnus-article-sort-functions
    (gnus-message 7 "Sorting articles...")
    (prog1
        (setq gnus-newsgroup-headers
              (sort articles (gnus-make-sort-function
                              gnus-article-sort-functions)))
      (gnus-message 7 "Sorting articles...done"))))

;; Written by Hallvard B Furuseth <h.b.furuseth@usit.uio.no>.
(defmacro gnus-thread-header (thread)
  "Return header of first article in THREAD.
Note that THREAD must never, ever be anything else than a variable -
using some other form will lead to serious barfage."
  (or (symbolp thread) (signal 'wrong-type-argument '(symbolp thread)))
  ;; (8% speedup to gnus-summary-prepare, just for fun :-)
  (list 'byte-code "\10\211:\203\17\0\211@;\203\16\0A@@\207"
        (vector thread) 2))

(defsubst gnus-article-sort-by-number (h1 h2)
  "Sort articles by article number."
  (< (mail-header-number h1)
     (mail-header-number h2)))

(defun gnus-thread-sort-by-number (h1 h2)
  "Sort threads by root article number."
  (gnus-article-sort-by-number
   (gnus-thread-header h1) (gnus-thread-header h2)))

(defsubst gnus-article-sort-by-random (h1 h2)
  "Sort articles randomly."
  (zerop (random 2)))

(defun gnus-thread-sort-by-random (h1 h2)
  "Sort threads randomly."
  (gnus-article-sort-by-random
   (gnus-thread-header h1) (gnus-thread-header h2)))

(defsubst gnus-article-sort-by-lines (h1 h2)
  "Sort articles by article Lines header."
  (< (mail-header-lines h1)
     (mail-header-lines h2)))

(defun gnus-thread-sort-by-lines (h1 h2)
  "Sort threads by root article Lines header."
  (gnus-article-sort-by-lines
   (gnus-thread-header h1) (gnus-thread-header h2)))

(defsubst gnus-article-sort-by-chars (h1 h2)
  "Sort articles by octet length."
  (< (mail-header-chars h1)
     (mail-header-chars h2)))

(defun gnus-thread-sort-by-chars (h1 h2)
  "Sort threads by root article octet length."
  (gnus-article-sort-by-chars
   (gnus-thread-header h1) (gnus-thread-header h2)))

(defsubst gnus-article-sort-by-author (h1 h2)
  "Sort articles by root author."
  (gnus-string<
   (let ((extract (funcall
                   gnus-extract-address-components
                   (mail-header-from h1))))
     (or (car extract) (cadr extract) ""))
   (let ((extract (funcall
                   gnus-extract-address-components
                   (mail-header-from h2))))
     (or (car extract) (cadr extract) ""))))

(defun gnus-thread-sort-by-author (h1 h2)
  "Sort threads by root author."
  (gnus-article-sort-by-author
   (gnus-thread-header h1)  (gnus-thread-header h2)))

(defsubst gnus-article-sort-by-recipient (h1 h2)
  "Sort articles by recipient."
  (gnus-string<
   (let ((extract (funcall
                   gnus-extract-address-components
                   (or (cdr (assq 'To (mail-header-extra h1))) ""))))
     (or (car extract) (cadr extract)))
   (let ((extract (funcall
                   gnus-extract-address-components
                   (or (cdr (assq 'To (mail-header-extra h2))) ""))))
     (or (car extract) (cadr extract)))))

(defun gnus-thread-sort-by-recipient (h1 h2)
  "Sort threads by root recipient."
  (gnus-article-sort-by-recipient
   (gnus-thread-header h1) (gnus-thread-header h2)))

(defsubst gnus-article-sort-by-subject (h1 h2)
  "Sort articles by root subject."
  (gnus-string<
   (downcase (gnus-simplify-subject-re (mail-header-subject h1)))
   (downcase (gnus-simplify-subject-re (mail-header-subject h2)))))

(defun gnus-thread-sort-by-subject (h1 h2)
  "Sort threads by root subject."
  (gnus-article-sort-by-subject
   (gnus-thread-header h1) (gnus-thread-header h2)))

(defsubst gnus-article-sort-by-date (h1 h2)
  "Sort articles by root article date."
  (time-less-p
   (gnus-date-get-time (mail-header-date h1))
   (gnus-date-get-time (mail-header-date h2))))

(defun gnus-thread-sort-by-date (h1 h2)
  "Sort threads by root article date."
  (gnus-article-sort-by-date
   (gnus-thread-header h1) (gnus-thread-header h2)))

(defsubst gnus-article-sort-by-score (h1 h2)
  "Sort articles by root article score.
Unscored articles will be counted as having a score of zero."
  (> (or (cdr (assq (mail-header-number h1)
                    gnus-newsgroup-scored))
         gnus-summary-default-score 0)
     (or (cdr (assq (mail-header-number h2)
                    gnus-newsgroup-scored))
         gnus-summary-default-score 0)))

(defun gnus-thread-sort-by-score (h1 h2)
  "Sort threads by root article score."
  (gnus-article-sort-by-score
   (gnus-thread-header h1) (gnus-thread-header h2)))

(defun gnus-thread-sort-by-total-score (h1 h2)
  "Sort threads by the sum of all scores in the thread.
Unscored articles will be counted as having a score of zero."
  (> (gnus-thread-total-score h1) (gnus-thread-total-score h2)))

(defun gnus-thread-total-score (thread)
  ;; This function find the total score of THREAD.
  (cond
   ((null thread)
    0)
   ((consp thread)
    (if (stringp (car thread))
        (apply gnus-thread-score-function 0
               (mapcar 'gnus-thread-total-score-1 (cdr thread)))
      (gnus-thread-total-score-1 thread)))
   (t
    (gnus-thread-total-score-1 (list thread)))))

(defun gnus-article-sort-by-most-recent-number (h1 h2)
  "Sort articles by number."
  (gnus-article-sort-by-number h1 h2))

(defun gnus-thread-sort-by-most-recent-number (h1 h2)
  "Sort threads such that the thread with the most recently arrived article comes first."
  (> (gnus-thread-highest-number h1) (gnus-thread-highest-number h2)))

(defun gnus-thread-highest-number (thread)
  "Return the highest article number in THREAD."
  (apply 'max (mapcar (lambda (header)
                        (mail-header-number header))
                      (message-flatten-list thread))))

(defun gnus-article-sort-by-most-recent-date (h1 h2)
  "Sort articles by number."
  (gnus-article-sort-by-date h1 h2))

(defun gnus-thread-sort-by-most-recent-date (h1 h2)
  "Sort threads such that the thread with the most recently dated article comes first."
  (> (gnus-thread-latest-date h1) (gnus-thread-latest-date h2)))

; Since this is called not only to sort the top-level threads, but
; also in recursive sorts to order the articles within a thread, each
; article will be processed many times.  Thus it speeds things up
; quite a bit to use gnus-date-get-time, which caches the time value.
(defun gnus-thread-latest-date (thread)
  "Return the highest article date in THREAD."
  (apply 'max
         (mapcar (lambda (header) (gnus-float-time
                                   (gnus-date-get-time
                                    (mail-header-date header))))
                 (message-flatten-list thread))))

(defun gnus-thread-total-score-1 (root)
  ;; This function find the total score of the thread below ROOT.
  (setq root (car root))
  (apply gnus-thread-score-function
         (or (append
              (mapcar 'gnus-thread-total-score
                      (cdr (gnus-id-to-thread (mail-header-id root))))
              (when (> (mail-header-number root) 0)
                (list (or (cdr (assq (mail-header-number root)
                                     gnus-newsgroup-scored))
                          gnus-summary-default-score 0))))
             (list gnus-summary-default-score)
             '(0))))

;; Added by Per Abrahamsen <amanda@iesd.auc.dk>.
(defvar gnus-tmp-prev-subject nil)
(defvar gnus-tmp-false-parent nil)
(defvar gnus-tmp-root-expunged nil)
(defvar gnus-tmp-dummy-line nil)

(defun gnus-extra-header (type &optional header)
  "Return the extra header of TYPE."
  (or (cdr (assq type (mail-header-extra (or header gnus-tmp-header))))
      ""))

(defvar gnus-tmp-thread-tree-header-string "")

(defcustom gnus-sum-thread-tree-root "> "
  "With %B spec, used for the root of a thread.
If nil, use subject instead."
  :version "22.1"
  :type '(radio (const :format "%v  " nil) string)
  :group 'gnus-thread)

(defcustom gnus-sum-thread-tree-false-root "> "
  "With %B spec, used for a false root of a thread.
If nil, use subject instead."
  :version "22.1"
  :type '(radio (const :format "%v  " nil) string)
  :group 'gnus-thread)

(defcustom gnus-sum-thread-tree-single-indent ""
  "With %B spec, used for a thread with just one message.
If nil, use subject instead."
  :version "22.1"
  :type '(radio (const :format "%v  " nil) string)
  :group 'gnus-thread)

(defcustom gnus-sum-thread-tree-vertical "| "
  "With %B spec, used for drawing a vertical line."
  :version "22.1"
  :type 'string
  :group 'gnus-thread)

(defcustom gnus-sum-thread-tree-indent "  "
  "With %B spec, used for indenting."
  :version "22.1"
  :type 'string
  :group 'gnus-thread)

(defcustom gnus-sum-thread-tree-leaf-with-other "+-> "
  "With %B spec, used for a leaf with brothers."
  :version "22.1"
  :type 'string
  :group 'gnus-thread)

(defcustom gnus-sum-thread-tree-single-leaf "\\-> "
  "With %B spec, used for a leaf without brothers."
  :version "22.1"
  :type 'string
  :group 'gnus-thread)

(defcustom gnus-summary-display-while-building nil
  "If non-nil, show and update the summary buffer as it's being built.
If the value is t, update the buffer after every line is inserted.  If
the value is an integer (N), update the display every N lines."
  :version "22.1"
  :group 'gnus-thread
  :type '(choice (const :tag "off" nil)
                 number
                 (const :tag "frequently" t)))

(defun gnus-summary-prepare-threads (threads)
  "Prepare summary buffer from THREADS and indentation LEVEL.
THREADS is either a list of `(PARENT [(CHILD1 [(GRANDCHILD ...]...) ...])'
or a straight list of headers."
  (gnus-message 7 "Generating summary...")

  (setq gnus-newsgroup-threads threads)
  (beginning-of-line)

  (let ((gnus-tmp-level 0)
        (default-score (or gnus-summary-default-score 0))
        (gnus-visual-p (gnus-visual-p 'summary-highlight 'highlight))
        (building-line-count gnus-summary-display-while-building)
        (building-count (integerp gnus-summary-display-while-building))
        thread number subject stack state gnus-tmp-gathered beg-match
        new-roots gnus-tmp-new-adopts thread-end simp-subject
        gnus-tmp-header gnus-tmp-unread gnus-tmp-downloaded
        gnus-tmp-replied gnus-tmp-subject-or-nil
        gnus-tmp-dummy gnus-tmp-indentation gnus-tmp-lines gnus-tmp-score
        gnus-tmp-score-char gnus-tmp-from gnus-tmp-name
        gnus-tmp-number gnus-tmp-opening-bracket gnus-tmp-closing-bracket
        tree-stack)

    (setq gnus-tmp-prev-subject nil
          gnus-tmp-thread-tree-header-string "")

    (if (vectorp (car threads))
        ;; If this is a straight (sic) list of headers, then a
        ;; threaded summary display isn't required, so we just create
        ;; an unthreaded one.
        (gnus-summary-prepare-unthreaded threads)

      ;; Do the threaded display.

      (if gnus-summary-display-while-building
          (switch-to-buffer (buffer-name)))
      (while (or threads stack gnus-tmp-new-adopts new-roots)

        (if (and (= gnus-tmp-level 0)
                 (or (not stack)
                     (= (caar stack) 0))
                 (not gnus-tmp-false-parent)
                 (or gnus-tmp-new-adopts new-roots))
            (if gnus-tmp-new-adopts
                (setq gnus-tmp-level (if gnus-tmp-root-expunged 0 1)
                      thread (list (car gnus-tmp-new-adopts))
                      gnus-tmp-header (caar thread)
                      gnus-tmp-new-adopts (cdr gnus-tmp-new-adopts))
              (when new-roots
                (setq thread (list (car new-roots))
                      gnus-tmp-header (caar thread)
                      new-roots (cdr new-roots))))

          (if threads
              ;; If there are some threads, we do them before the
              ;; threads on the stack.
              (setq thread threads
                    gnus-tmp-header (caar thread))
            ;; There were no current threads, so we pop something off
            ;; the stack.
            (setq state (car stack)
                  gnus-tmp-level (car state)
                  tree-stack (cadr state)
                  thread (caddr state)
                  stack (cdr stack)
                  gnus-tmp-header (caar thread))))

        (setq gnus-tmp-false-parent nil)
        (setq gnus-tmp-root-expunged nil)
        (setq thread-end nil)

        (if (stringp gnus-tmp-header)
            ;; The header is a dummy root.
            (cond
             ((eq gnus-summary-make-false-root 'adopt)
              ;; We let the first article adopt the rest.
              (setq gnus-tmp-new-adopts (nconc gnus-tmp-new-adopts
                                               (cddar thread)))
              (setq gnus-tmp-gathered
                    (nconc (mapcar
                            (lambda (h) (mail-header-number (car h)))
                            (cddar thread))
                           gnus-tmp-gathered))
              (setq thread (cons (list (caar thread)
                                       (cadar thread))
                                 (cdr thread)))
              (setq gnus-tmp-level -1
                    gnus-tmp-false-parent t))
             ((eq gnus-summary-make-false-root 'empty)
              ;; We print adopted articles with empty subject fields.
              (setq gnus-tmp-gathered
                    (nconc (mapcar
                            (lambda (h) (mail-header-number (car h)))
                            (cddar thread))
                           gnus-tmp-gathered))
              (setq gnus-tmp-level -1))
             ((eq gnus-summary-make-false-root 'dummy)
              ;; We remember that we probably want to output a dummy
              ;; root.
              (setq gnus-tmp-dummy-line gnus-tmp-header)
              (setq gnus-tmp-prev-subject gnus-tmp-header))
             (t
              ;; We do not make a root for the gathered
              ;; sub-threads at all.
              (setq gnus-tmp-level -1)))

          (setq number (mail-header-number gnus-tmp-header)
                subject (mail-header-subject gnus-tmp-header)
                simp-subject (gnus-simplify-subject-fully subject))

          (cond
           ;; If the thread has changed subject, we might want to make
           ;; this subthread into a root.
           ((and (null gnus-thread-ignore-subject)
                 (not (zerop gnus-tmp-level))
                 gnus-tmp-prev-subject
                 (not (string= gnus-tmp-prev-subject simp-subject)))
            (setq new-roots (nconc new-roots (list (car thread)))
                  thread-end t
                  gnus-tmp-header nil))
           ;; If the article lies outside the current limit,
           ;; then we do not display it.
           ((not (memq number gnus-newsgroup-limit))
            (setq gnus-tmp-gathered
                  (nconc (mapcar
                          (lambda (h) (mail-header-number (car h)))
                          (cdar thread))
                         gnus-tmp-gathered))
            (setq gnus-tmp-new-adopts (if (cdar thread)
                                          (append gnus-tmp-new-adopts
                                                  (cdar thread))
                                        gnus-tmp-new-adopts)
                  thread-end t
                  gnus-tmp-header nil)
            (when (zerop gnus-tmp-level)
              (setq gnus-tmp-root-expunged t)))
           ;; Perhaps this article is to be marked as read?
           ((and gnus-summary-mark-below
                 (< (or (cdr (assq number gnus-newsgroup-scored))
                        default-score)
                    gnus-summary-mark-below)
                 ;; Don't touch sparse articles.
                 (not (gnus-summary-article-sparse-p number))
                 (not (gnus-summary-article-ancient-p number)))
            (setq gnus-newsgroup-unreads
                  (delq number gnus-newsgroup-unreads))
            (if gnus-newsgroup-auto-expire
                (setq gnus-newsgroup-expirable
                      (gnus-add-to-sorted-list
                       gnus-newsgroup-expirable number))
              (push (cons number gnus-low-score-mark)
                    gnus-newsgroup-reads))))

          (when gnus-tmp-header
            ;; We may have an old dummy line to output before this
            ;; article.
            (when (and gnus-tmp-dummy-line
                       (gnus-subject-equal
                        gnus-tmp-dummy-line
                        (mail-header-subject gnus-tmp-header)))
              (gnus-summary-insert-dummy-line
               gnus-tmp-dummy-line (mail-header-number gnus-tmp-header))
              (setq gnus-tmp-dummy-line nil))

            ;; Compute the mark.
            (setq gnus-tmp-unread (gnus-article-mark number))

            (push (gnus-data-make number gnus-tmp-unread (1+ (point))
                                  gnus-tmp-header gnus-tmp-level)
                  gnus-newsgroup-data)

            ;; Actually insert the line.
            (setq
             gnus-tmp-subject-or-nil
             (cond
              ((and gnus-thread-ignore-subject
                    gnus-tmp-prev-subject
                    (not (string= gnus-tmp-prev-subject simp-subject)))
               subject)
              ((zerop gnus-tmp-level)
               (if (and (eq gnus-summary-make-false-root 'empty)
                        (memq number gnus-tmp-gathered)
                        gnus-tmp-prev-subject
                        (string= gnus-tmp-prev-subject simp-subject))
                   gnus-summary-same-subject
                 subject))
              (t gnus-summary-same-subject)))
            (if (and (eq gnus-summary-make-false-root 'adopt)
                     (= gnus-tmp-level 1)
                     (memq number gnus-tmp-gathered))
                (setq gnus-tmp-opening-bracket ?\<
                      gnus-tmp-closing-bracket ?\>)
              (setq gnus-tmp-opening-bracket ?\[
                    gnus-tmp-closing-bracket ?\]))
            (if (>= gnus-tmp-level (length gnus-thread-indent-array))
                (gnus-make-thread-indent-array
                 (max (* 2 (length gnus-thread-indent-array))
                      gnus-tmp-level)))
            (setq
             gnus-tmp-indentation
             (aref gnus-thread-indent-array gnus-tmp-level)
             gnus-tmp-lines (mail-header-lines gnus-tmp-header)
             gnus-tmp-score (or (cdr (assq number gnus-newsgroup-scored))
                                gnus-summary-default-score 0)
             gnus-tmp-score-char
             (if (or (null gnus-summary-default-score)
                     (<= (abs (- gnus-tmp-score gnus-summary-default-score))
                         gnus-summary-zcore-fuzz))
                 ?                      ;Whitespace
               (if (< gnus-tmp-score gnus-summary-default-score)
                   gnus-score-below-mark gnus-score-over-mark))
             gnus-tmp-replied
             (cond ((memq number gnus-newsgroup-processable)
                    gnus-process-mark)
                   ((memq number gnus-newsgroup-cached)
                    gnus-cached-mark)
                   ((memq number gnus-newsgroup-replied)
                    gnus-replied-mark)
                   ((memq number gnus-newsgroup-forwarded)
                    gnus-forwarded-mark)
                   ((memq number gnus-newsgroup-saved)
                    gnus-saved-mark)
                   ((memq number gnus-newsgroup-unseen)
                    gnus-unseen-mark)
                   (t gnus-no-mark))
             gnus-tmp-downloaded
             (cond ((memq number gnus-newsgroup-undownloaded)
                    gnus-undownloaded-mark)
                   (gnus-newsgroup-agentized
                    gnus-downloaded-mark)
                   (t
                    gnus-no-mark))
             gnus-tmp-from (mail-header-from gnus-tmp-header)
             gnus-tmp-name
             (cond
              ((string-match "<[^>]+> *$" gnus-tmp-from)
               (setq beg-match (match-beginning 0))
               (or (and (string-match "^\".+\"" gnus-tmp-from)
                        (substring gnus-tmp-from 1 (1- (match-end 0))))
                   (substring gnus-tmp-from 0 beg-match)))
              ((string-match "(.+)" gnus-tmp-from)
               (substring gnus-tmp-from
                          (1+ (match-beginning 0)) (1- (match-end 0))))
              (t gnus-tmp-from))

             ;; Do the %B string
             gnus-tmp-thread-tree-header-string
             (cond
              ((not gnus-show-threads) "")
              ((zerop gnus-tmp-level)
               (cond ((cdar thread)
                      (or gnus-sum-thread-tree-root subject))
                     (gnus-tmp-new-adopts
                      (or gnus-sum-thread-tree-false-root subject))
                     (t
                      (or gnus-sum-thread-tree-single-indent subject))))
              (t
               (concat (apply 'concat
                              (mapcar (lambda (item)
                                        (if (= item 1)
                                            gnus-sum-thread-tree-vertical
                                          gnus-sum-thread-tree-indent))
                                      (cdr (reverse tree-stack))))
                       (if (nth 1 thread)
                           gnus-sum-thread-tree-leaf-with-other
                         gnus-sum-thread-tree-single-leaf)))))
            (when (string= gnus-tmp-name "")
              (setq gnus-tmp-name gnus-tmp-from))
            (unless (numberp gnus-tmp-lines)
              (setq gnus-tmp-lines -1))
            (if (= gnus-tmp-lines -1)
                (setq gnus-tmp-lines "?")
              (setq gnus-tmp-lines (number-to-string gnus-tmp-lines)))
            (gnus-put-text-property
             (point)
             (progn (eval gnus-summary-line-format-spec) (point))
             'gnus-number number)
            (when gnus-visual-p
              (forward-line -1)
              (gnus-summary-highlight-line)
              (when gnus-summary-update-hook
                (gnus-run-hooks 'gnus-summary-update-hook))
              (forward-line 1))

            (setq gnus-tmp-prev-subject simp-subject)))

        (when (nth 1 thread)
          (push (list (max 0 gnus-tmp-level)
                      (copy-sequence tree-stack)
                      (nthcdr 1 thread))
                stack))
        (push (if (nth 1 thread) 1 0) tree-stack)
        (incf gnus-tmp-level)
        (setq threads (if thread-end nil (cdar thread)))
        (if gnus-summary-display-while-building
            (if building-count
                (progn
                  ;; use a set frequency
                  (setq building-line-count (1- building-line-count))
                  (when (= building-line-count 0)
                    (sit-for 0)
                    (setq building-line-count
                          gnus-summary-display-while-building)))
              ;; always
              (sit-for 0)))
        (unless threads
          (setq gnus-tmp-level 0)))))
  (gnus-message 7 "Generating summary...done"))

(defun gnus-summary-prepare-unthreaded (headers)
  "Generate an unthreaded summary buffer based on HEADERS."
  (let (header number mark)

    (beginning-of-line)

    (while headers
      ;; We may have to root out some bad articles...
      (when (memq (setq number (mail-header-number
                                (setq header (pop headers))))
                  gnus-newsgroup-limit)
        ;; Mark article as read when it has a low score.
        (when (and gnus-summary-mark-below
                   (< (or (cdr (assq number gnus-newsgroup-scored))
                          gnus-summary-default-score 0)
                      gnus-summary-mark-below)
                   (not (gnus-summary-article-ancient-p number)))
          (setq gnus-newsgroup-unreads
                (delq number gnus-newsgroup-unreads))
          (if gnus-newsgroup-auto-expire
              (push number gnus-newsgroup-expirable)
            (push (cons number gnus-low-score-mark)
                  gnus-newsgroup-reads)))

        (setq mark (gnus-article-mark number))
        (push (gnus-data-make number mark (1+ (point)) header 0)
              gnus-newsgroup-data)
        (gnus-summary-insert-line
         header 0 number
         (memq number gnus-newsgroup-undownloaded)
         mark (memq number gnus-newsgroup-replied)
         (memq number gnus-newsgroup-expirable)
         (mail-header-subject header) nil
         (cdr (assq number gnus-newsgroup-scored))
         (memq number gnus-newsgroup-processable))))))

(defun gnus-group-get-list-identifiers (group)
  "Get list identifier regexp for GROUP."
  (or (gnus-parameter-list-identifier group)
      (if (consp gnus-list-identifiers)
          (mapconcat 'identity gnus-list-identifiers " *\\|")
        gnus-list-identifiers)))

(defun gnus-summary-remove-list-identifiers ()
  "Remove list identifiers in `gnus-list-identifiers' from articles in the current group."
  (let ((regexp (gnus-group-get-list-identifiers gnus-newsgroup-name))
        changed subject)
    (when regexp
      (setq regexp (concat "^\\(?:R[Ee]: +\\)*\\(" regexp " *\\)"))
      (dolist (header gnus-newsgroup-headers)
        (setq subject (mail-header-subject header)
              changed nil)
        (while (string-match regexp subject)
          (setq subject
                (concat (substring subject 0 (match-beginning 1))
                        (substring subject (match-end 0)))
                changed t))
        (when changed
          (when (string-match "^\\(\\(?:R[Ee]: +\\)+\\)R[Ee]: +" subject)
            (setq subject
                  (concat (substring subject 0 (match-beginning 1))
                          (substring subject (match-end 1)))))
          (mail-header-set-subject header subject))))))

(defun gnus-fetch-headers (articles &optional limit force-new dependencies)
  "Fetch headers of ARTICLES."
  (let ((name (gnus-group-decoded-name gnus-newsgroup-name)))
    (gnus-message 7 "Fetching headers for %s..." name)
    (prog1
        (if (eq 'nov
                (setq gnus-headers-retrieved-by
                      (gnus-retrieve-headers
                       articles gnus-newsgroup-name
                       (or limit
                           ;; We might want to fetch old headers, but
                           ;; not if there is only 1 article.
                           (and (or (and
                                     (not (eq gnus-fetch-old-headers 'some))
                                     (not (numberp gnus-fetch-old-headers)))
                                    (> (length articles) 1))
                                gnus-fetch-old-headers)))))
            (gnus-get-newsgroup-headers-xover
             articles force-new dependencies gnus-newsgroup-name t)
          (gnus-get-newsgroup-headers dependencies force-new))
      (gnus-message 7 "Fetching headers for %s...done" name))))

(defun gnus-select-newsgroup (group &optional read-all select-articles)
  "Select newsgroup GROUP.
If READ-ALL is non-nil, all articles in the group are selected.
If SELECT-ARTICLES, only select those articles from GROUP."
  (let* ((entry (gnus-group-entry group))
         ;;!!! Dirty hack; should be removed.
         (gnus-summary-ignore-duplicates
          (if (eq (car (gnus-find-method-for-group group)) 'nnvirtual)
              t
            gnus-summary-ignore-duplicates))
         (info (nth 2 entry))
         charset articles fetched-articles cached)

    (unless (gnus-check-server
             (set (make-local-variable 'gnus-current-select-method)
                  (gnus-find-method-for-group group)))
      (error "Couldn't open server"))
    (setq charset (gnus-group-name-charset gnus-current-select-method group))

    (or (and entry (not (eq (car entry) t))) ; Either it's active...
        (gnus-activate-group group)     ; Or we can activate it...
        (progn                          ; Or we bug out.
          (when (equal major-mode 'gnus-summary-mode)
            (gnus-kill-buffer (current-buffer)))
          (error
           "Couldn't activate group %s: %s"
           (mm-decode-coding-string group charset)
           (mm-decode-coding-string (gnus-status-message group) charset))))

    (unless (gnus-request-group group t)
      (when (equal major-mode 'gnus-summary-mode)
        (gnus-kill-buffer (current-buffer)))
      (error "Couldn't request group %s: %s"
             (mm-decode-coding-string group charset)
             (mm-decode-coding-string (gnus-status-message group) charset)))

    (when (and gnus-agent
               (gnus-active group))
      (gnus-agent-possibly-alter-active group (gnus-active group) info)

      (setq gnus-summary-use-undownloaded-faces
            (gnus-agent-find-parameter
             group
             'agent-enable-undownloaded-faces)))

    (setq gnus-newsgroup-name group
          gnus-newsgroup-unselected nil
          gnus-newsgroup-unreads (gnus-list-of-unread-articles group))

    (let ((display (gnus-group-find-parameter group 'display)))
      (setq gnus-newsgroup-display
            (cond
             ((not (zerop (or (car-safe read-all) 0)))
              ;; The user entered the group with C-u SPC/RET, let's show
              ;; all articles.
              'gnus-not-ignore)
             ((eq display 'all)
              'gnus-not-ignore)
             ((arrayp display)
              (gnus-summary-display-make-predicate (mapcar 'identity display)))
             ((numberp display)
              ;; The following is probably the "correct" solution, but
              ;; it makes Gnus fetch all headers and then limit the
              ;; articles (which is slow), so instead we hack the
              ;; select-articles parameter instead. -- Simon Josefsson
              ;; <jas@kth.se>
              ;;
              ;; (gnus-byte-compile
              ;;  `(lambda () (> number ,(- (cdr (gnus-active group))
              ;;                         display)))))
              (setq select-articles
                    (gnus-uncompress-range
                     (cons (let ((tmp (- (cdr (gnus-active group)) display)))
                             (if (> tmp 0)
                                 tmp
                               1))
                           (cdr (gnus-active group)))))
              nil)
             (t
              nil))))

    (gnus-summary-setup-default-charset)

    ;; Kludge to avoid having cached articles nixed out in virtual groups.
    (when (gnus-virtual-group-p group)
      (setq cached gnus-newsgroup-cached))

    (setq gnus-newsgroup-unreads
          (gnus-sorted-ndifference
           (gnus-sorted-ndifference gnus-newsgroup-unreads
                                    gnus-newsgroup-marked)
           gnus-newsgroup-dormant))

    (setq gnus-newsgroup-processable nil)

    (gnus-update-read-articles group gnus-newsgroup-unreads t)

    ;; Adjust and set lists of article marks.
    (when info
      (gnus-adjust-marked-articles info))
    (if (setq articles select-articles)
        (setq gnus-newsgroup-unselected
              (gnus-sorted-difference gnus-newsgroup-unreads articles))
      (setq articles (gnus-articles-to-read group read-all)))

    (cond
     ((null articles)
      ;;(gnus-message 3 "Couldn't select newsgroup -- no articles to display")
      'quit)
     ((eq articles 0) nil)
     (t
      ;; Init the dependencies hash table.
      (setq gnus-newsgroup-dependencies
            (gnus-make-hashtable (length articles)))
      (gnus-set-global-variables)
      ;; Retrieve the headers and read them in.

      (setq gnus-newsgroup-headers (gnus-fetch-headers articles))

      ;; Kludge to avoid having cached articles nixed out in virtual groups.
      (when cached
        (setq gnus-newsgroup-cached cached))

      ;; Suppress duplicates?
      (when gnus-suppress-duplicates
        (gnus-dup-suppress-articles))

      ;; Set the initial limit.
      (setq gnus-newsgroup-limit (copy-sequence articles))
      ;; Remove canceled articles from the list of unread articles.
      (setq fetched-articles
            (mapcar (lambda (headers) (mail-header-number headers))
                    gnus-newsgroup-headers))
      (setq gnus-newsgroup-articles fetched-articles)
      (setq gnus-newsgroup-unreads
            (gnus-sorted-nintersection
             gnus-newsgroup-unreads fetched-articles))
      (gnus-compute-unseen-list)

      ;; Removed marked articles that do not exist.
      (gnus-update-missing-marks
       (gnus-sorted-difference articles fetched-articles))
      ;; We might want to build some more threads first.
      (when (and gnus-fetch-old-headers
                 (eq gnus-headers-retrieved-by 'nov))
        (if (eq gnus-fetch-old-headers 'invisible)
            (gnus-build-all-threads)
          (gnus-build-old-threads)))
      ;; Let the Gnus agent mark articles as read.
      (when gnus-agent
        (gnus-agent-get-undownloaded-list))
      ;; Remove list identifiers from subject
      (gnus-summary-remove-list-identifiers)
      ;; Check whether auto-expire is to be done in this group.
      (setq gnus-newsgroup-auto-expire
            (and (gnus-group-auto-expirable-p group)
                 (not (gnus-group-read-only-p group))))
      ;; Set up the article buffer now, if necessary.
      (unless (and gnus-single-article-buffer
                   (equal gnus-article-buffer "*Article*"))
        (gnus-article-setup-buffer))
      ;; First and last article in this newsgroup.
      (when gnus-newsgroup-headers
        (setq gnus-newsgroup-begin
              (mail-header-number (car gnus-newsgroup-headers))
              gnus-newsgroup-end
              (mail-header-number
               (gnus-last-element gnus-newsgroup-headers))))
      ;; GROUP is successfully selected.
      (or gnus-newsgroup-headers t)))))

(defun gnus-compute-unseen-list ()
  ;; The `seen' marks are treated specially.
  (if (not gnus-newsgroup-seen)
      (setq gnus-newsgroup-unseen gnus-newsgroup-articles)
    (setq gnus-newsgroup-unseen
          (gnus-inverse-list-range-intersection
           gnus-newsgroup-articles gnus-newsgroup-seen))))

(declare-function gnus-get-predicate "gnus-agent" (predicate))

(defun gnus-summary-display-make-predicate (display)
  (require 'gnus-agent)
  (when (= (length display) 1)
    (setq display (car display)))
  (unless gnus-summary-display-cache
    (dolist (elem (append '((unread . unread)
                            (read . read)
                            (unseen . unseen))
                          gnus-article-mark-lists))
      (push (cons (cdr elem)
                  (gnus-byte-compile    ;Why bother?
                   `(lambda () (gnus-article-marked-p ',(cdr elem)))))
            gnus-summary-display-cache)))
  (let ((gnus-category-predicate-alist gnus-summary-display-cache)
        (gnus-category-predicate-cache gnus-summary-display-cache))
    (gnus-get-predicate display)))

;; Uses the dynamically bound `gnus-number' variable.
(defvar gnus-number)
(defun gnus-article-marked-p (type &optional article)
  (let ((article (or article gnus-number)))
    (cond
     ((eq type 'tick)
      (memq article gnus-newsgroup-marked))
     ((eq type 'spam)
      (memq article gnus-newsgroup-spam-marked))
     ((eq type 'unsend)
      (memq article gnus-newsgroup-unsendable))
     ((eq type 'undownload)
      (memq article gnus-newsgroup-undownloaded))
     ((eq type 'download)
      (memq article gnus-newsgroup-downloadable))
     ((eq type 'unread)
      (memq article gnus-newsgroup-unreads))
     ((eq type 'read)
      (memq article gnus-newsgroup-reads))
     ((eq type 'dormant)
      (memq article gnus-newsgroup-dormant) )
     ((eq type 'expire)
      (memq article gnus-newsgroup-expirable))
     ((eq type 'reply)
      (memq article gnus-newsgroup-replied))
     ((eq type 'killed)
      (memq article gnus-newsgroup-killed))
     ((eq type 'bookmark)
      (assq article gnus-newsgroup-bookmarks))
     ((eq type 'score)
      (assq article gnus-newsgroup-scored))
     ((eq type 'save)
      (memq article gnus-newsgroup-saved))
     ((eq type 'cache)
      (memq article gnus-newsgroup-cached))
     ((eq type 'forward)
      (memq article gnus-newsgroup-forwarded))
     ((eq type 'seen)
      (not (memq article gnus-newsgroup-unseen)))
     (t t))))

(defun gnus-articles-to-read (group &optional read-all)
  "Find out what articles the user wants to read."
  (let* ((only-read-p t)
         (articles
          ;; Select all articles if `read-all' is non-nil, or if there
          ;; are no unread articles.
          (if (or read-all
                  (and (zerop (length gnus-newsgroup-marked))
                       (zerop (length gnus-newsgroup-unreads)))
                  ;; Fetch all if the predicate is non-nil.
                  gnus-newsgroup-display)
              ;; We want to select the headers for all the articles in
              ;; the group, so we select either all the active
              ;; articles in the group, or (if that's nil), the
              ;; articles in the cache.
              (or
               (if gnus-newsgroup-maximum-articles
                   (let ((active (gnus-active group)))
                     (gnus-uncompress-range
                      (cons (max (car active)
                                 (- (cdr active)
                                    gnus-newsgroup-maximum-articles
                                    -1))
                            (cdr active))))
                 (gnus-uncompress-range (gnus-active group)))
               (gnus-cache-articles-in-group group))
            ;; Select only the "normal" subset of articles.
            (setq only-read-p nil)
            (gnus-sorted-nunion
             (gnus-sorted-union gnus-newsgroup-dormant gnus-newsgroup-marked)
             gnus-newsgroup-unreads)))
         (scored-list (gnus-killed-articles gnus-newsgroup-killed articles))
         (scored (length scored-list))
         (number (length articles))
         (marked (+ (length gnus-newsgroup-marked)
                    (length gnus-newsgroup-dormant)))
         (select
          (cond
           ((numberp read-all)
            read-all)
           ((numberp gnus-newsgroup-display)
            gnus-newsgroup-display)
           (t
            (condition-case ()
                (cond
                 ((and (or (<= scored marked) (= scored number))
                       (numberp gnus-large-newsgroup)
                       (> number gnus-large-newsgroup))
                  (let* ((cursor-in-echo-area nil)
                         (initial (gnus-parameter-large-newsgroup-initial
                                   gnus-newsgroup-name))
                         (default (if only-read-p
                                      (or initial gnus-large-newsgroup)
                                    number))
                         (input
                          (read-string
                           (if only-read-p
                               (format
                                "How many articles from %s (available %d, default %d): "
                                (gnus-group-decoded-name
                                 (gnus-group-real-name gnus-newsgroup-name))
                                number default)
                             (format
                              "How many articles from %s (%d default): "
                              (gnus-group-decoded-name
                               (gnus-group-real-name gnus-newsgroup-name))
                              default))
                           nil
                           nil
                           (number-to-string default))))
                    (if (string-match "^[ \t]*$" input) number input)))
                 ((and (> scored marked) (< scored number)
                       (> (- scored number) 20))
                  (let ((input
                         (read-string
                          (format "%s %s (%d scored, %d total): "
                                  "How many articles from"
                                  (gnus-group-decoded-name
                                   (gnus-group-real-name gnus-newsgroup-name))
                                  scored number))))
                    (if (string-match "^[ \t]*$" input)
                        number input)))
                 (t number))
              (quit
               (message "Quit getting the articles to read")
               nil))))))
    (setq select (if (stringp select) (string-to-number select) select))
    (if (or (null select) (zerop select))
        select
      (if (and (not (zerop scored)) (<= (abs select) scored))
          (progn
            (setq articles (sort scored-list '<))
            (setq number (length articles)))
        (setq articles (copy-sequence articles)))

      (when (< (abs select) number)
        (if (< select 0)
            ;; Select the N oldest articles.
            (setcdr (nthcdr (1- (abs select)) articles) nil)
          ;; Select the N most recent articles.
          (setq articles (nthcdr (- number select) articles))))
      (setq gnus-newsgroup-unselected
            (gnus-sorted-difference gnus-newsgroup-unreads articles))
      (when gnus-alter-articles-to-read-function
        (setq articles
              (sort
               (funcall gnus-alter-articles-to-read-function
                        gnus-newsgroup-name articles)
               '<)))
      articles)))

(defun gnus-killed-articles (killed articles)
  (let (out)
    (while articles
      (when (inline (gnus-member-of-range (car articles) killed))
        (push (car articles) out))
      (setq articles (cdr articles)))
    out))

(defun gnus-uncompress-marks (marks)
  "Uncompress the mark ranges in MARKS."
  (let ((uncompressed '(score bookmark))
        out)
    (while marks
      (if (memq (caar marks) uncompressed)
          (push (car marks) out)
        (push (cons (caar marks) (gnus-uncompress-range (cdar marks))) out))
      (setq marks (cdr marks)))
    out))

(defun gnus-article-mark-to-type (mark)
  "Return the type of MARK."
  (or (cadr (assq mark gnus-article-special-mark-lists))
      'list))

(defun gnus-article-unpropagatable-p (mark)
  "Return whether MARK should be propagated to back end."
  (memq mark gnus-article-unpropagated-mark-lists))

(defun gnus-adjust-marked-articles (info)
  "Set all article lists and remove all marks that are no longer valid."
  (let* ((marked-lists (gnus-info-marks info))
         (active (gnus-active (gnus-info-group info)))
         (min (car active))
         (max (cdr active))
         (types gnus-article-mark-lists)
         marks var articles article mark mark-type
         bgn end)
    ;; Hack to avoid adjusting marks for imap.
    (when (eq (car (gnus-find-method-for-group (gnus-info-group info)))
              'nnimap)
      (setq min 1))

    (dolist (marks marked-lists)
      (setq mark (car marks)
            mark-type (gnus-article-mark-to-type mark)
            var (intern (format "gnus-newsgroup-%s" (car (rassq mark types)))))

      ;; We set the variable according to the type of the marks list,
      ;; and then adjust the marks to a subset of the active articles.
      (cond
       ;; Adjust "simple" lists - compressed yet unsorted
       ((eq mark-type 'list)
        ;; Simultaneously uncompress and clip to active range
        ;; See gnus-uncompress-range for a description of possible marks
        (let (l lh)
          (if (not (cadr marks))
              (set var nil)
            (setq articles (if (numberp (cddr marks))
                               (list (cdr marks))
                             (cdr marks))
                  lh (cons nil nil)
                  l lh)

            (while (setq article (pop articles))
              (cond ((consp article)
                     (setq bgn (max (car article) min)
                           end (min (cdr article) max))
                     (while (<= bgn end)
                       (setq l (setcdr l (cons bgn nil))
                             bgn (1+ bgn))))
                    ((and (<= min article)
                          (>= max article))
                     (setq l (setcdr l (cons article nil))))))
            (set var (cdr lh)))))
       ;; Adjust assocs.
       ((eq mark-type 'tuple)
        (set var (setq articles (cdr marks)))
        (when (not (listp (cdr (symbol-value var))))
          (set var (list (symbol-value var))))
        (when (not (listp (cdr articles)))
          (setq articles (list article