Use defalias, not fset.

[gnus] / lisp / gnus-art.el

;;; gnus-art.el --- article mode commands for Gnus
;; Copyright (C) 1996, 1997, 1998, 1999, 2000 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 2, or (at your option)
;; any later version.

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

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

;;; Commentary:

;;; Code:

(eval-when-compile (require 'cl))

(require 'gnus)
(require 'gnus-sum)
(require 'gnus-spec)
(require 'gnus-int)
(require 'mm-bodies)
(require 'mail-parse)
(require 'mm-decode)
(require 'mm-view)
(require 'wid-edit)
(require 'mm-uu)

(defgroup gnus-article nil
  "Article display."
  :link '(custom-manual "(gnus)The Article Buffer")
  :group 'gnus)

(defgroup gnus-article-treat nil
  "Treating article parts."
  :link '(custom-manual "(gnus)Article Hiding")
  :group 'gnus-article)

(defgroup gnus-article-hiding nil
  "Hiding article parts."
  :link '(custom-manual "(gnus)Article Hiding")
  :group 'gnus-article)

(defgroup gnus-article-highlight nil
  "Article highlighting."
  :link '(custom-manual "(gnus)Article Highlighting")
  :group 'gnus-article
  :group 'gnus-visual)

(defgroup gnus-article-signature nil
  "Article signatures."
  :link '(custom-manual "(gnus)Article Signature")
  :group 'gnus-article)

(defgroup gnus-article-headers nil
  "Article headers."
  :link '(custom-manual "(gnus)Hiding Headers")
  :group 'gnus-article)

(defgroup gnus-article-washing nil
  "Special commands on articles."
  :link '(custom-manual "(gnus)Article Washing")
  :group 'gnus-article)

(defgroup gnus-article-emphasis nil
  "Fontisizing articles."
  :link '(custom-manual "(gnus)Article Fontisizing")
  :group 'gnus-article)

(defgroup gnus-article-saving nil
  "Saving articles."
  :link '(custom-manual "(gnus)Saving Articles")
  :group 'gnus-article)

(defgroup gnus-article-mime nil
  "Worshiping the MIME wonder."
  :link '(custom-manual "(gnus)Using MIME")
  :group 'gnus-article)

(defgroup gnus-article-buttons nil
  "Pushable buttons in the article buffer."
  :link '(custom-manual "(gnus)Article Buttons")
  :group 'gnus-article)

(defgroup gnus-article-various nil
  "Other article options."
  :link '(custom-manual "(gnus)Misc Article")
  :group 'gnus-article)

(defcustom gnus-ignored-headers
  '("^Path:" "^Expires:" "^Date-Received:" "^References:" "^Xref:" "^Lines:"
    "^Relay-Version:" "^Message-ID:" "^Approved:" "^Sender:" "^Received:"
    "^X-UIDL:" "^MIME-Version:" "^Return-Path:" "^In-Reply-To:"
    "^Content-Type:" "^Content-Transfer-Encoding:" "^X-WebTV-Signature:"
    "^X-MimeOLE:" "^X-MSMail-Priority:" "^X-Priority:" "^X-Loop:"
    "^X-Authentication-Warning:" "^X-MIME-Autoconverted:" "^X-Face:"
    "^X-Attribution:" "^X-Originating-IP:" "^Delivered-To:"
    "^NNTP-[-A-Za-z]+:" "^Distribution:" "^X-no-archive:" "^X-Trace:"
    "^X-Complaints-To:" "^X-NNTP-Posting-Host:" "^X-Orig.*:"
    "^Abuse-Reports-To:" "^Cache-Post-Path:" "^X-Article-Creation-Date:"
    "^X-Poster:" "^X-Mail2News-Path:" "^X-Server-Date:" "^X-Cache:"
    "^Originator:" "^X-Problems-To:" "^X-Auth-User:" "^X-Post-Time:"
    "^X-Admin:" "^X-UID:" "^Resent-[-A-Za-z]+:" "^X-Mailing-List:"
    "^Precedence:" "^Original-[-A-Za-z]+:" "^X-filename:" "^X-Orcpt:"
    "^Old-Received:" "^X-Pgp" "^X-Auth:" "^X-From-Line:"
    "^X-Gnus-Article-Number:" "^X-Majordomo:" "^X-Url:" "^X-Sender:"
    "^MBOX-Line" "^Priority:" "^X-Pgp" "^X400-[-A-Za-z]+:"
    "^Status:" "^X-Gnus-Mail-Source:" "^Cancel-Lock:"
    "^X-FTN" "^X-EXP32-SerialNo:" "^Encoding:" "^Importance:"
    "^Autoforwarded:" "^Original-Encoded-Information-Types:" "^X-Ya-Pop3:"
    "^X-Face-Version:" "^X-Vms-To:" "^X-ML-NAME:" "^X-ML-COUNT:"
    "^Mailing-List:" "^X-finfo:" "^X-md5sum:" "^X-md5sum-Origin:"
    "^X-Sun-Charset:" "^X-Accept-Language:" "^X-Envelope-Sender:"
    "^List-[A-Za-z]+:" "^X-Listprocessor-Version:"
    "^X-Received:" "^X-Distribute:" "^X-Sequence:" "^X-Juno-Line-Breaks:"
    "^X-Notes-Item:" "^X-MS-TNEF-Correlator:" "^x-uunet-gateway:"
    "^X-Received:" "^Content-length:" "X-precedence:")
  "*All headers that start with this regexp will be hidden.
This variable can also be a list of regexps of headers to be ignored.
If `gnus-visible-headers' is non-nil, this variable will be ignored."
  :type '(choice :custom-show nil
                 regexp
                 (repeat regexp))
  :group 'gnus-article-hiding)

(defcustom gnus-visible-headers
  "^From:\\|^Newsgroups:\\|^Subject:\\|^Date:\\|^Followup-To:\\|^Reply-To:\\|^Organization:\\|^Summary:\\|^Keywords:\\|^To:\\|^[BGF]?Cc:\\|^Posted-To:\\|^Mail-Copies-To:\\|^Apparently-To:\\|^Gnus-Warning:\\|^Resent-From:\\|^X-Sent:"
  "*All headers that do not match this regexp will be hidden.
This variable can also be a list of regexp of headers to remain visible.
If this variable is non-nil, `gnus-ignored-headers' will be ignored."
  :type '(repeat :value-to-internal (lambda (widget value)
                                      (custom-split-regexp-maybe value))
                 :match (lambda (widget value)
                          (or (stringp value)
                              (widget-editable-list-match widget value)))
                 regexp)
  :group 'gnus-article-hiding)

(defcustom gnus-sorted-header-list
  '("^From:" "^Subject:" "^Summary:" "^Keywords:" "^Newsgroups:"
    "^Followup-To:" "^To:" "^Cc:" "^Date:" "^Organization:")
  "*This variable is a list of regular expressions.
If it is non-nil, headers that match the regular expressions will
be placed first in the article buffer in the sequence specified by
this list."
  :type '(repeat regexp)
  :group 'gnus-article-hiding)

(defcustom gnus-boring-article-headers '(empty followup-to reply-to)
  "Headers that are only to be displayed if they have interesting data.
Possible values in this list are `empty', `newsgroups', `followup-to',
`reply-to', `date', `long-to', and `many-to'."
  :type '(set (const :tag "Headers with no content." empty)
              (const :tag "Newsgroups with only one group." newsgroups)
              (const :tag "Followup-to identical to newsgroups." followup-to)
              (const :tag "Reply-to identical to from." reply-to)
              (const :tag "Date less than four days old." date)
              (const :tag "Very long To and/or Cc header." long-to)
              (const :tag "Multiple To and/or Cc headers." many-to))
  :group 'gnus-article-hiding)

(defcustom gnus-signature-separator '("^-- $" "^-- *$")
  "Regexp matching signature separator.
This can also be a list of regexps.  In that case, it will be checked
from head to tail looking for a separator.  Searches will be done from
the end of the buffer."
  :type '(repeat string)
  :group 'gnus-article-signature)

(defcustom gnus-signature-limit nil
  "Provide a limit to what is considered a signature.
If it is a number, no signature may not be longer (in characters) than
that number.  If it is a floating point number, no signature may be
longer (in lines) than that number.  If it is a function, the function
will be called without any parameters, and if it returns nil, there is
no signature in the buffer.  If it is a string, it will be used as a
regexp.  If it matches, the text in question is not a signature."
  :type '(choice (integer :value 200)
                 (number :value 4.0)
                 (function :value fun)
                 (regexp :value ".*"))
  :group 'gnus-article-signature)

(defcustom gnus-hidden-properties '(invisible t intangible t)
  "Property list to use for hiding text."
  :type 'sexp
  :group 'gnus-article-hiding)

(defcustom gnus-article-x-face-command
  (if (and (fboundp 'image-type-available-p)
           (image-type-available-p 'xbm))
      'gnus-article-display-xface
    "{ echo '/* Width=48, Height=48 */'; uncompface; } | icontopbm | display -")
  "*String or function to be executed to display an X-Face header.
If it is a string, the command will be executed in a sub-shell
asynchronously.  The compressed face will be piped to this command."
  :type '(choice string
                 (function-item gnus-article-display-xface)
                 function)
  :group 'gnus-article-washing)

(defcustom gnus-article-x-face-too-ugly nil
  "Regexp matching posters whose face shouldn't be shown automatically."
  :type '(choice regexp (const nil))
  :group 'gnus-article-washing)

(defcustom gnus-emphasis-alist
  (let ((format
         "\\(\\s-\\|^\\|[-\"]\\|\\s(\\)\\(%s\\(\\w+\\(\\s-+\\w+\\)*[.,]?\\)%s\\)\\(\\s-\\|[-,;:\"]\\s-\\|[?!.]+\\s-\\|\\s)\\)")
        (types
         '(("_" "_" underline)
           ("/" "/" italic)
           ("\\*" "\\*" bold)
           ("_/" "/_" underline-italic)
           ("_\\*" "\\*_" underline-bold)
           ("\\*/" "/\\*" bold-italic)
           ("_\\*/" "/\\*_" underline-bold-italic))))
    `(("\\(\\s-\\|^\\)\\(_\\(\\(\\w\\|_[^_]\\)+\\)_\\)\\(\\s-\\|[?!.,;]\\)"
       2 3 gnus-emphasis-underline)
      ,@(mapcar
         (lambda (spec)
           (list
            (format format (car spec) (cadr spec))
            2 3 (intern (format "gnus-emphasis-%s" (nth 2 spec)))))
         types)))
  "*Alist that says how to fontify certain phrases.
Each item looks like this:

  (\"_\\\\(\\\\w+\\\\)_\" 0 1 'underline)

The first element is a regular expression to be matched.  The second
is a number that says what regular expression grouping used to find
the entire emphasized word.  The third is a number that says what
regexp grouping should be displayed and highlighted.  The fourth
is the face used for highlighting."
  :type '(repeat (list :value ("" 0 0 default)
                       regexp
                       (integer :tag "Match group")
                       (integer :tag "Emphasize group")
                       face))
  :group 'gnus-article-emphasis)

(defcustom gnus-emphasize-whitespace-regexp "^[ \t]+\\|[ \t]*\n"
  "A regexp to describe whitespace which should not be emphasized.
Typical values are \"^[ \\t]+\\\\|[ \\t]*\\n\" and \"[ \\t]+\\\\|[ \\t]*\\n\".
The former avoids underlining of leading and trailing whitespace,
and the latter avoids underlining any whitespace at all."
  :group 'gnus-article-emphasis
  :type 'regexp)

(defface gnus-emphasis-bold '((t (:bold t)))
  "Face used for displaying strong emphasized text (*word*)."
  :group 'gnus-article-emphasis)

(defface gnus-emphasis-italic '((t (:italic t)))
  "Face used for displaying italic emphasized text (/word/)."
  :group 'gnus-article-emphasis)

(defface gnus-emphasis-underline '((t (:underline t)))
  "Face used for displaying underlined emphasized text (_word_)."
  :group 'gnus-article-emphasis)

(defface gnus-emphasis-underline-bold '((t (:bold t :underline t)))
  "Face used for displaying underlined bold emphasized text (_*word*_)."
  :group 'gnus-article-emphasis)

(defface gnus-emphasis-underline-italic '((t (:italic t :underline t)))
  "Face used for displaying underlined italic emphasized text (_/word/_)."
  :group 'gnus-article-emphasis)

(defface gnus-emphasis-bold-italic '((t (:bold t :italic t)))
  "Face used for displaying bold italic emphasized text (/*word*/)."
  :group 'gnus-article-emphasis)

(defface gnus-emphasis-underline-bold-italic
  '((t (:bold t :italic t :underline t)))
  "Face used for displaying underlined bold italic emphasized text.
Esample: (_/*word*/_)."
  :group 'gnus-article-emphasis)

(defface gnus-emphasis-highlight-words
  '((t (:background "black" :foreground "yellow")))
  "Face used for displaying highlighted words."
  :group 'gnus-article-emphasis)

(defcustom gnus-article-time-format "%a, %b %d %Y %T %Z"
  "Format for display of Date headers in article bodies.
See `format-time-string' for the possible values.

The variable can also be function, which should return a complete Date
header.  The function is called with one argument, the time, which can
be fed to `format-time-string'."
  :type '(choice string symbol)
  :link '(custom-manual "(gnus)Article Date")
  :group 'gnus-article-washing)

(eval-and-compile
  (autoload 'mail-extract-address-components "mail-extr"))

(defcustom gnus-save-all-headers t
  "*If non-nil, don't remove any headers before saving."
  :group 'gnus-article-saving
  :type 'boolean)

(defcustom gnus-prompt-before-saving 'always
  "*This variable says how much prompting is to be done when saving articles.
If it is nil, no prompting will be done, and the articles will be
saved to the default files.  If this variable is `always', each and
every article that is saved will be preceded by a prompt, even when
saving large batches of articles.  If this variable is neither nil not
`always', there the user will be prompted once for a file name for
each invocation of the saving commands."
  :group 'gnus-article-saving
  :type '(choice (item always)
                 (item :tag "never" nil)
                 (sexp :tag "once" :format "%t\n" :value t)))

(defcustom gnus-saved-headers gnus-visible-headers
  "Headers to keep if `gnus-save-all-headers' is nil.
If `gnus-save-all-headers' is non-nil, this variable will be ignored.
If that variable is nil, however, all headers that match this regexp
will be kept while the rest will be deleted before saving."
  :group 'gnus-article-saving
  :type 'regexp)

(defcustom gnus-default-article-saver 'gnus-summary-save-in-rmail
  "A function to save articles in your favourite format.
The function must be interactively callable (in other words, it must
be an Emacs command).

Gnus provides the following functions:

* gnus-summary-save-in-rmail (Rmail format)
* gnus-summary-save-in-mail (Unix mail format)
* gnus-summary-save-in-folder (MH folder)
* gnus-summary-save-in-file (article format)
* gnus-summary-save-in-vm (use VM's folder format)
* gnus-summary-write-to-file (article format -- overwrite)."
  :group 'gnus-article-saving
  :type '(radio (function-item gnus-summary-save-in-rmail)
                (function-item gnus-summary-save-in-mail)
                (function-item gnus-summary-save-in-folder)
                (function-item gnus-summary-save-in-file)
                (function-item gnus-summary-save-in-vm)
                (function-item gnus-summary-write-to-file)))

(defcustom gnus-rmail-save-name 'gnus-plain-save-name
  "A function generating a file name to save articles in Rmail format.
The function is called with NEWSGROUP, HEADERS, and optional LAST-FILE."
  :group 'gnus-article-saving
  :type 'function)

(defcustom gnus-mail-save-name 'gnus-plain-save-name
  "A function generating a file name to save articles in Unix mail format.
The function is called with NEWSGROUP, HEADERS, and optional LAST-FILE."
  :group 'gnus-article-saving
  :type 'function)

(defcustom gnus-folder-save-name 'gnus-folder-save-name
  "A function generating a file name to save articles in MH folder.
The function is called with NEWSGROUP, HEADERS, and optional LAST-FOLDER."
  :group 'gnus-article-saving
  :type 'function)

(defcustom gnus-file-save-name 'gnus-numeric-save-name
  "A function generating a file name to save articles in article format.
The function is called with NEWSGROUP, HEADERS, and optional
LAST-FILE."
  :group 'gnus-article-saving
  :type 'function)

(defcustom gnus-split-methods
  '((gnus-article-archive-name)
    (gnus-article-nndoc-name))
  "*Variable used to suggest where articles are to be saved.
For instance, if you would like to save articles related to Gnus in
the file \"gnus-stuff\", and articles related to VM in \"vm-stuff\",
you could set this variable to something like:

 '((\"^Subject:.*gnus\\|^Newsgroups:.*gnus\" \"gnus-stuff\")
   (\"^Subject:.*vm\\|^Xref:.*vm\" \"vm-stuff\"))

This variable is an alist where the where the key is the match and the
value is a list of possible files to save in if the match is non-nil.

If the match is a string, it is used as a regexp match on the
article.  If the match is a symbol, that symbol will be funcalled
from the buffer of the article to be saved with the newsgroup as the
parameter.  If it is a list, it will be evaled in the same buffer.

If this form or function returns a string, this string will be used as
a possible file name; and if it returns a non-nil list, that list will
be used as possible file names."
  :group 'gnus-article-saving
  :type '(repeat (choice (list :value (fun) function)
                         (cons :value ("" "") regexp (repeat string))
                         (sexp :value nil))))

(defcustom gnus-page-delimiter "^\^L"
  "*Regexp describing what to use as article page delimiters.
The default value is \"^\^L\", which is a form linefeed at the
beginning of a line."
  :type 'regexp
  :group 'gnus-article-various)

(defcustom gnus-article-mode-line-format "Gnus: %g [%w] %S%m"
  "*The format specification for the article mode line.
See `gnus-summary-mode-line-format' for a closer description.

The following additional specs are available:

%w  The article washing status.
%m  The number of MIME parts in the article."
  :type 'string
  :group 'gnus-article-various)

(defcustom gnus-article-mode-hook nil
  "*A hook for Gnus article mode."
  :type 'hook
  :group 'gnus-article-various)

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

(defcustom gnus-article-prepare-hook nil
  "*A hook called after an article has been prepared in the article buffer."
  :type 'hook
  :group 'gnus-article-various)

(defcustom gnus-article-hide-pgp-hook nil
  "*A hook called after successfully hiding a PGP signature."
  :type 'hook
  :group 'gnus-article-various)

(defcustom gnus-article-button-face 'bold
  "Face used for highlighting buttons in the article buffer.

An article button is a piece of text that you can activate by pressing
`RET' or `mouse-2' above it."
  :type 'face
  :group 'gnus-article-buttons)

(defcustom gnus-article-mouse-face 'highlight
  "Face used for mouse highlighting in the article buffer.

Article buttons will be displayed in this face when the cursor is
above them."
  :type 'face
  :group 'gnus-article-buttons)

(defcustom gnus-signature-face 'gnus-signature-face
  "Face used for highlighting a signature in the article buffer.
Obsolete; use the face `gnus-signature-face' for customizations instead."
  :type 'face
  :group 'gnus-article-highlight
  :group 'gnus-article-signature)

(defface gnus-signature-face
  '((((type x))
     (:italic t)))
  "Face used for highlighting a signature in the article buffer."
  :group 'gnus-article-highlight
  :group 'gnus-article-signature)

(defface gnus-header-from-face
  '((((class color)
      (background dark))
     (:foreground "spring green"))
    (((class color)
      (background light))
     (:foreground "red3"))
    (t
     (:italic t)))
  "Face used for displaying from headers."
  :group 'gnus-article-headers
  :group 'gnus-article-highlight)

(defface gnus-header-subject-face
  '((((class color)
      (background dark))
     (:foreground "SeaGreen3"))
    (((class color)
      (background light))
     (:foreground "red4"))
    (t
     (:bold t :italic t)))
  "Face used for displaying subject headers."
  :group 'gnus-article-headers
  :group 'gnus-article-highlight)

(defface gnus-header-newsgroups-face
  '((((class color)
      (background dark))
     (:foreground "yellow" :italic t))
    (((class color)
      (background light))
     (:foreground "MidnightBlue" :italic t))
    (t
     (:italic t)))
  "Face used for displaying newsgroups headers."
  :group 'gnus-article-headers
  :group 'gnus-article-highlight)

(defface gnus-header-name-face
  '((((class color)
      (background dark))
     (:foreground "SeaGreen"))
    (((class color)
      (background light))
     (:foreground "maroon"))
    (t
     (:bold t)))
  "Face used for displaying header names."
  :group 'gnus-article-headers
  :group 'gnus-article-highlight)

(defface gnus-header-content-face
  '((((class color)
      (background dark))
     (:foreground "forest green" :italic t))
    (((class color)
      (background light))
     (:foreground "indianred4" :italic t))
    (t
     (:italic t)))  "Face used for displaying header content."
  :group 'gnus-article-headers
  :group 'gnus-article-highlight)

(defcustom gnus-header-face-alist
  '(("From" nil gnus-header-from-face)
    ("Subject" nil gnus-header-subject-face)
    ("Newsgroups:.*," nil gnus-header-newsgroups-face)
    ("" gnus-header-name-face gnus-header-content-face))
  "*Controls highlighting of article header.

An alist of the form (HEADER NAME CONTENT).

HEADER is a regular expression which should match the name of an
header header and NAME and CONTENT are either face names or nil.

The name of each header field will be displayed using the face
specified by the first element in the list where HEADER match the
header name and NAME is non-nil.  Similarly, the content will be
displayed by the first non-nil matching CONTENT face."
  :group 'gnus-article-headers
  :group 'gnus-article-highlight
  :type '(repeat (list (regexp :tag "Header")
                       (choice :tag "Name"
                               (item :tag "skip" nil)
                               (face :value default))
                       (choice :tag "Content"
                               (item :tag "skip" nil)
                               (face :value default)))))

(defcustom gnus-article-decode-hook
  '(article-decode-charset article-decode-encoded-words)
  "*Hook run to decode charsets in articles."
  :group 'gnus-article-headers
  :type 'hook)

(defcustom gnus-display-mime-function 'gnus-display-mime
  "Function to display MIME articles."
  :group 'gnus-article-mime
  :type 'function)

(defvar gnus-decode-header-function 'mail-decode-encoded-word-region
  "Function used to decode headers.")

(defvar gnus-article-dumbquotes-map
  '(("\202" ",")
    ("\203" "f")
    ("\204" ",,")
    ("\205" "...")
    ("\213" "<")
    ("\214" "OE")
    ("\221" "`")
    ("\222" "'")
    ("\223" "``")
    ("\224" "\"")
    ("\225" "*")
    ("\226" "---")
    ("\227" "-")
    ("\231" "(TM)")
    ("\233" ">")
    ("\234" "oe")
    ("\264" "'"))
  "Table for MS-to-Latin1 translation.")

(defcustom gnus-ignored-mime-types nil
  "List of MIME types that should be ignored by Gnus."
  :group 'gnus-article-mime
  :type '(repeat regexp))

(defcustom gnus-unbuttonized-mime-types '(".*/.*")
  "List of MIME types that should not be given buttons when rendered inline."
  :group 'gnus-article-mime
  :type '(repeat regexp))

(defcustom gnus-article-mime-part-function nil
  "Function called with a MIME handle as the argument.
This is meant for people who want to do something automatic based
on parts -- for instance, adding Vcard info to a database."
  :group 'gnus-article-mime
  :type 'function)

(defcustom gnus-mime-multipart-functions nil
  "An alist of MIME types to functions to display them.")

(defcustom gnus-article-date-lapsed-new-header nil
  "Whether the X-Sent and Date headers can coexist.
When using `gnus-treat-date-lapsed', the \"X-Sent:\" header will
either replace the old \"Date:\" header (if this variable is nil), or
be added below it (otherwise)."
  :group 'gnus-article-headers
  :type 'boolean)

(defcustom gnus-article-mime-match-handle-function 'undisplayed-alternative
  "Function called with a MIME handle as the argument.
This is meant for people who want to view first matched part.
For `undisplayed-alternative' (default), the first undisplayed 
part or alternative part is used.  For `undisplayed', the first 
undisplayed part is used.  For a function, the first part which 
the function return `t' is used.  For `nil', the first part is
used."
  :group 'gnus-article-mime
  :type '(choice 
          (item :tag "first" :value nil)
          (item :tag "undisplayed" :value undisplayed)
          (item :tag "undisplayed or alternative" 
                :value undisplayed-alternative)
          (function)))

;;;
;;; The treatment variables
;;;

(defvar gnus-part-display-hook nil
  "Hook called on parts that are to receive treatment.")

(defvar gnus-article-treat-custom
  '(choice (const :tag "Off" nil)
           (const :tag "On" t)
           (const :tag "Header" head)
           (const :tag "Last" last)
           (integer :tag "Less")
           (repeat :tag "Groups" regexp)
           (sexp :tag "Predicate")))

(defvar gnus-article-treat-head-custom
  '(choice (const :tag "Off" nil)
           (const :tag "Header" head)))

(defvar gnus-article-treat-types '("text/plain")
  "Parts to treat.")

(defvar gnus-inhibit-treatment nil
  "Whether to inhibit treatment.")

(defcustom gnus-treat-highlight-signature '(or last (typep "text/x-vcard"))
  "Highlight the signature.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)
(put 'gnus-treat-highlight-signature 'highlight t)

(defcustom gnus-treat-buttonize 100000
  "Add buttons.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)
(put 'gnus-treat-buttonize 'highlight t)

(defcustom gnus-treat-buttonize-head 'head
  "Add buttons to the head.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-head-custom)
(put 'gnus-treat-buttonize-head 'highlight t)

(defcustom gnus-treat-emphasize 50000
  "Emphasize text.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)
(put 'gnus-treat-emphasize 'highlight t)

(defcustom gnus-treat-strip-cr nil
  "Remove carriage returns.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)

(defcustom gnus-treat-hide-headers 'head
  "Hide headers.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-head-custom)

(defcustom gnus-treat-hide-boring-headers nil
  "Hide boring headers.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-head-custom)

(defcustom gnus-treat-hide-signature nil
  "Hide the signature.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)

(defcustom gnus-treat-fill-article nil
  "Fill the article.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)

(defcustom gnus-treat-hide-citation nil
  "Hide cited text.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)

(defcustom gnus-treat-strip-list-identifiers 'head
  "Strip list identifiers from `gnus-list-identifiers`.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)

(defcustom gnus-treat-strip-pgp t
  "Strip PGP signatures.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)

(defcustom gnus-treat-strip-pem nil
  "Strip PEM signatures.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)

(defcustom gnus-treat-strip-banner t
  "Strip banners from articles.
The banner to be stripped is specified in the `banner' group parameter.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)

(defcustom gnus-treat-highlight-headers 'head
  "Highlight the headers.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-head-custom)
(put 'gnus-treat-highlight-headers 'highlight t)

(defcustom gnus-treat-highlight-citation t
  "Highlight cited text.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)
(put 'gnus-treat-highlight-citation 'highlight t)

(defcustom gnus-treat-date-ut nil
  "Display the Date in UT (GMT).
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-head-custom)

(defcustom gnus-treat-date-local nil
  "Display the Date in the local timezone.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-head-custom)

(defcustom gnus-treat-date-lapsed nil
  "Display the Date header in a way that says how much time has elapsed.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-head-custom)

(defcustom gnus-treat-date-original nil
  "Display the date in the original timezone.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-head-custom)

(defcustom gnus-treat-date-iso8601 nil
  "Display the date in the ISO8601 format.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-head-custom)

(defcustom gnus-treat-date-user-defined nil
  "Display the date in a user-defined format.
The format is defined by the `gnus-article-time-format' variable.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-head-custom)

(defcustom gnus-treat-strip-headers-in-body t
  "Strip the X-No-Archive header line from the beginning of the body.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)

(defcustom gnus-treat-strip-trailing-blank-lines nil
  "Strip trailing blank lines.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)

(defcustom gnus-treat-strip-leading-blank-lines nil
  "Strip leading blank lines.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)

(defcustom gnus-treat-strip-multiple-blank-lines nil
  "Strip multiple blank lines.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)

(defcustom gnus-treat-overstrike t
  "Treat overstrike highlighting.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)
(put 'gnus-treat-overstrike 'highlight t)

(defcustom gnus-treat-display-xface (if (and gnus-xemacs (featurep 'xface))
                                        'head nil)
  "Display X-Face headers.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-head-custom)
(put 'gnus-treat-display-xface 'highlight t)

(defcustom gnus-treat-display-smileys (if (and gnus-xemacs
                                               (featurep 'xpm))
                                          t nil)
  "Display smileys.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)
(put 'gnus-treat-display-smileys 'highlight t)

(defcustom gnus-treat-display-picons (if gnus-xemacs 'head nil)
  "Display picons.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-head-custom)
(put 'gnus-treat-display-picons 'highlight t)

(defcustom gnus-treat-capitalize-sentences nil
  "Capitalize sentence-starting words.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)

(defcustom gnus-treat-fill-long-lines nil
  "Fill long lines.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)

(defcustom gnus-treat-play-sounds nil
  "Play sounds.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)

(defcustom gnus-treat-translate nil
  "Translate articles from one language to another.
Valid values are nil, t, `head', `last', an integer or a predicate.
See the manual for details."
  :group 'gnus-article-treat
  :type gnus-article-treat-custom)

;;; Internal variables

(defvar article-goto-body-goes-to-point-min-p nil)
(defvar gnus-article-wash-types nil)
(defvar gnus-article-emphasis-alist nil)

(defvar gnus-article-mime-handle-alist-1 nil)
(defvar gnus-treatment-function-alist
  '((gnus-treat-strip-banner gnus-article-strip-banner)
    (gnus-treat-strip-headers-in-body gnus-article-strip-headers-in-body)
    (gnus-treat-highlight-signature gnus-article-highlight-signature)
    (gnus-treat-buttonize gnus-article-add-buttons)
    (gnus-treat-fill-article gnus-article-fill-cited-article)
    (gnus-treat-fill-long-lines gnus-article-fill-long-lines)
    (gnus-treat-strip-cr gnus-article-remove-cr)
    (gnus-treat-emphasize gnus-article-emphasize)
    (gnus-treat-display-xface gnus-article-display-x-face)
    (gnus-treat-hide-headers gnus-article-maybe-hide-headers)
    (gnus-treat-hide-boring-headers gnus-article-hide-boring-headers)
    (gnus-treat-hide-signature gnus-article-hide-signature)
    (gnus-treat-hide-citation gnus-article-hide-citation)
    (gnus-treat-strip-list-identifiers gnus-article-hide-list-identifiers)
    (gnus-treat-strip-pgp gnus-article-hide-pgp)
    (gnus-treat-strip-pem gnus-article-hide-pem)
    (gnus-treat-highlight-headers gnus-article-highlight-headers)
    (gnus-treat-highlight-citation gnus-article-highlight-citation)
    (gnus-treat-highlight-signature gnus-article-highlight-signature)
    (gnus-treat-date-ut gnus-article-date-ut)
    (gnus-treat-date-local gnus-article-date-local)
    (gnus-treat-date-lapsed gnus-article-date-lapsed)
    (gnus-treat-date-original gnus-article-date-original)
    (gnus-treat-date-user-defined gnus-article-date-user)
    (gnus-treat-date-iso8601 gnus-article-date-iso8601)
    (gnus-treat-strip-trailing-blank-lines
     gnus-article-remove-trailing-blank-lines)
    (gnus-treat-strip-leading-blank-lines
     gnus-article-strip-leading-blank-lines)
    (gnus-treat-strip-multiple-blank-lines
     gnus-article-strip-multiple-blank-lines)
    (gnus-treat-overstrike gnus-article-treat-overstrike)
    (gnus-treat-buttonize-head gnus-article-add-buttons-to-head)
    (gnus-treat-display-smileys gnus-smiley-display)
    (gnus-treat-capitalize-sentences gnus-article-capitalize-sentences)
    (gnus-treat-display-picons gnus-article-display-picons)
    (gnus-treat-play-sounds gnus-earcon-display)))

(defvar gnus-article-mime-handle-alist nil)
(defvar article-lapsed-timer nil)
(defvar gnus-article-current-summary nil)

(defvar gnus-article-mode-syntax-table
  (let ((table (copy-syntax-table text-mode-syntax-table)))
    (modify-syntax-entry ?- "w" table)
    (modify-syntax-entry ?> ")" table)
    (modify-syntax-entry ?< "(" table)
    table)
  "Syntax table used in article mode buffers.
Initialized from `text-mode-syntax-table.")

(defvar gnus-save-article-buffer nil)

(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-number-of-articles-to-be-saved nil)

(defvar gnus-inhibit-hiding nil)

(defsubst gnus-article-hide-text (b e props)
  "Set text PROPS on the B to E region, extending `intangible' 1 past B."
  (add-text-properties b e props)
  (when (memq 'intangible props)
    (put-text-property
     (max (1- b) (point-min))
     b 'intangible (cddr (memq 'intangible props)))))
(defsubst gnus-article-unhide-text (b e)
  "Remove hidden text properties from region between B and E."
  (remove-text-properties b e gnus-hidden-properties)
  (when (memq 'intangible gnus-hidden-properties)
    (put-text-property (max (1- b) (point-min))
                       b 'intangible nil)))

(defun gnus-article-hide-text-type (b e type)
  "Hide text of TYPE between B and E."
  (push type gnus-article-wash-types)
  (gnus-article-hide-text
   b e (cons 'article-type (cons type gnus-hidden-properties))))

(defun gnus-article-unhide-text-type (b e type)
  "Unhide text of TYPE between B and E."
  (setq gnus-article-wash-types
        (delq type gnus-article-wash-types))
  (remove-text-properties
   b e (cons 'article-type (cons type gnus-hidden-properties)))
  (when (memq 'intangible gnus-hidden-properties)
    (put-text-property (max (1- b) (point-min))
                       b 'intangible nil)))

(defun gnus-article-hide-text-of-type (type)
  "Hide text of TYPE in the current buffer."
  (save-excursion
    (let ((b (point-min))
          (e (point-max)))
      (while (setq b (text-property-any b e 'article-type type))
        (add-text-properties b (incf b) gnus-hidden-properties)))))

(defun gnus-article-delete-text-of-type (type)
  "Delete text of TYPE in the current buffer."
  (save-excursion
    (let ((b (point-min)))
      (while (setq b (text-property-any b (point-max) 'article-type type))
        (delete-region
         b (or (text-property-not-all b (point-max) 'article-type type)
               (point-max)))))))

(defun gnus-article-delete-invisible-text ()
  "Delete all invisible text in the current buffer."
  (save-excursion
    (let ((b (point-min)))
      (while (setq b (text-property-any b (point-max) 'invisible t))
        (delete-region
         b (or (text-property-not-all b (point-max) 'invisible t)
               (point-max)))))))

(defun gnus-article-text-type-exists-p (type)
  "Say whether any text of type TYPE exists in the buffer."
  (text-property-any (point-min) (point-max) 'article-type type))

(defsubst gnus-article-header-rank ()
  "Give the rank of the string HEADER as given by `gnus-sorted-header-list'."
  (let ((list gnus-sorted-header-list)
        (i 0))
    (while list
      (when (looking-at (car list))
        (setq list nil))
      (setq list (cdr list))
      (incf i))
    i))

(defun article-hide-headers (&optional arg delete)
  "Hide unwanted headers and possibly sort them as well."
  (interactive)
  ;; This function might be inhibited.
  (unless gnus-inhibit-hiding
    (save-excursion
      (save-restriction
        (let ((buffer-read-only nil)
              (case-fold-search t)
              (max (1+ (length gnus-sorted-header-list)))
              (ignored (when (not gnus-visible-headers)
                         (cond ((stringp gnus-ignored-headers)
                                gnus-ignored-headers)
                               ((listp gnus-ignored-headers)
                                (mapconcat 'identity gnus-ignored-headers
                                           "\\|")))))
              (visible
               (cond ((stringp gnus-visible-headers)
                      gnus-visible-headers)
                     ((and gnus-visible-headers
                           (listp gnus-visible-headers))
                      (mapconcat 'identity gnus-visible-headers "\\|"))))
              (inhibit-point-motion-hooks t)
              beg)
          ;; First we narrow to just the headers.
          (article-narrow-to-head)
          ;; Hide any "From " lines at the beginning of (mail) articles.
          (while (looking-at "From ")
            (forward-line 1))
          (unless (bobp)
            (delete-region (point-min) (point)))
          ;; Then treat the rest of the header lines.
          ;; Then we use the two regular expressions
          ;; `gnus-ignored-headers' and `gnus-visible-headers' to
          ;; select which header lines is to remain visible in the
          ;; article buffer.
          (while (re-search-forward "^[^ \t]*:" nil t)
            (beginning-of-line)
            ;; Mark the rank of the header.
            (put-text-property
             (point) (1+ (point)) 'message-rank
             (if (or (and visible (looking-at visible))
                     (and ignored
                          (not (looking-at ignored))))
                 (gnus-article-header-rank)
               (+ 2 max)))
            (forward-line 1))
          (message-sort-headers-1)
          (when (setq beg (text-property-any
                           (point-min) (point-max) 'message-rank (+ 2 max)))
            ;; We delete the unwanted headers.
            (push 'headers gnus-article-wash-types)
            (add-text-properties (point-min) (+ 5 (point-min))
                                 '(article-type headers dummy-invisible t))
            (delete-region beg (point-max))))))))

(defun article-hide-boring-headers (&optional arg)
  "Toggle hiding of headers that aren't very interesting.
If given a negative prefix, always show; if given a positive prefix,
always hide."
  (interactive (gnus-article-hidden-arg))
  (when (and (not (gnus-article-check-hidden-text 'boring-headers arg))
             (not gnus-show-all-headers))
    (save-excursion
      (save-restriction
        (let ((buffer-read-only nil)
              (list gnus-boring-article-headers)
              (inhibit-point-motion-hooks t)
              elem)
          (article-narrow-to-head)
          (while list
            (setq elem (pop list))
            (goto-char (point-min))
            (cond
             ;; Hide empty headers.
             ((eq elem 'empty)
              (while (re-search-forward "^[^: \t]+:[ \t]*\n[^ \t]" nil t)
                (forward-line -1)
                (gnus-article-hide-text-type
                 (progn (beginning-of-line) (point))
                 (progn
                   (end-of-line)
                   (if (re-search-forward "^[^ \t]" nil t)
                       (match-beginning 0)
                     (point-max)))
                 'boring-headers)))
             ;; Hide boring Newsgroups header.
             ((eq elem 'newsgroups)
              (when (equal (gnus-fetch-field "newsgroups")
                           (gnus-group-real-name
                            (if (boundp 'gnus-newsgroup-name)
                                gnus-newsgroup-name
                              "")))
                (gnus-article-hide-header "newsgroups")))
             ((eq elem 'followup-to)
              (when (equal (message-fetch-field "followup-to")
                           (message-fetch-field "newsgroups"))
                (gnus-article-hide-header "followup-to")))
             ((eq elem 'reply-to)
              (let ((from (message-fetch-field "from"))
                    (reply-to (message-fetch-field "reply-to")))
                (when (and
                       from reply-to
                       (ignore-errors
                         (equal
                          (nth 1 (mail-extract-address-components from))
                          (nth 1 (mail-extract-address-components reply-to)))))
                  (gnus-article-hide-header "reply-to"))))
             ((eq elem 'date)
              (let ((date (message-fetch-field "date")))
                (when (and date
                           (< (days-between (current-time-string) date)
                              4))
                  (gnus-article-hide-header "date"))))
             ((eq elem 'long-to)
              (let ((to (message-fetch-field "to"))
                    (cc (message-fetch-field "cc")))
                (when (> (length to) 1024)
                  (gnus-article-hide-header "to"))
                (when (> (length cc) 1024)
                  (gnus-article-hide-header "cc"))))
             ((eq elem 'many-to)
              (let ((to-count 0)
                    (cc-count 0))
                (goto-char (point-min))
                (while (re-search-forward "^to:" nil t)
                  (setq to-count (1+ to-count)))
                (when (> to-count 1)
                  (while (> to-count 0)
                    (goto-char (point-min))
                    (save-restriction
                      (re-search-forward "^to:" nil nil to-count)
                      (forward-line -1)
                      (narrow-to-region (point) (point-max))
                      (gnus-article-hide-header "to"))
                    (setq to-count (1- to-count))))
                (goto-char (point-min))
                (while (re-search-forward "^cc:" nil t)
                  (setq cc-count (1+ cc-count)))
                (when (> cc-count 1)
                  (while (> cc-count 0)
                    (goto-char (point-min))
                    (save-restriction
                      (re-search-forward "^cc:" nil nil cc-count)
                      (forward-line -1)
                      (narrow-to-region (point) (point-max))
                      (gnus-article-hide-header "cc"))
                    (setq cc-count (1- cc-count)))))))))))))

(defun gnus-article-hide-header (header)
  (save-excursion
    (goto-char (point-min))
    (when (re-search-forward (concat "^" header ":") nil t)
      (gnus-article-hide-text-type
       (progn (beginning-of-line) (point))
       (progn
         (end-of-line)
         (if (re-search-forward "^[^ \t]" nil t)
             (match-beginning 0)
           (point-max)))
       'boring-headers))))

(defvar gnus-article-normalized-header-length 40
  "Length of normalized headers.")

(defun article-normalize-headers ()
  "Make all header lines 40 characters long."
  (interactive)
  (let ((buffer-read-only nil)
        column)
    (save-excursion
      (save-restriction
        (article-narrow-to-head)
        (while (not (eobp))
          (cond
           ((< (setq column (- (gnus-point-at-eol) (point)))
               gnus-article-normalized-header-length)
            (end-of-line)
            (insert (make-string
                     (- gnus-article-normalized-header-length column)
                     ? )))
           ((> column gnus-article-normalized-header-length)
            (gnus-put-text-property
             (progn
               (forward-char gnus-article-normalized-header-length)
               (point))
             (gnus-point-at-eol)
             'invisible t))
           (t
            ;; Do nothing.
            ))
          (forward-line 1))))))

(defun article-treat-dumbquotes ()
  "Translate M******** sm*rtq**t*s into proper text.
Note that this function guesses whether a character is a sm*rtq**t* or
not, so it should only be used interactively."
  (interactive)
  (article-translate-strings gnus-article-dumbquotes-map))

(defun article-translate-characters (from to)
  "Translate all characters in the body of the article according to FROM and TO.
FROM is a string of characters to translate from; to is a string of
characters to translate to."
  (save-excursion
    (when (article-goto-body)
      (let ((buffer-read-only nil)
            (x (make-string 225 ?x))
            (i -1))
        (while (< (incf i) (length x))
          (aset x i i))
        (setq i 0)
        (while (< i (length from))
          (aset x (aref from i) (aref to i))
          (incf i))
        (translate-region (point) (point-max) x)))))

(defun article-translate-strings (map)
  "Translate all string in the body of the article according to MAP.
MAP is an alist where the elements are on the form (\"from\" \"to\")."
  (save-excursion
    (when (article-goto-body)
      (let ((buffer-read-only nil)
            elem)
        (while (setq elem (pop map))
          (save-excursion
            (while (search-forward (car elem) nil t)
              (replace-match (cadr elem)))))))))

(defun article-treat-overstrike ()
  "Translate overstrikes into bold text."
  (interactive)
  (save-excursion
    (when (article-goto-body)
      (let ((buffer-read-only nil))
        (while (search-forward "\b" nil t)
          (let ((next (char-after))
                (previous (char-after (- (point) 2))))
            ;; We do the boldification/underlining by hiding the
            ;; overstrikes and putting the proper text property
            ;; on the letters.
            (cond
             ((eq next previous)
              (gnus-article-hide-text-type (- (point) 2) (point) 'overstrike)
              (put-text-property (point) (1+ (point)) 'face 'bold))
             ((eq next ?_)
              (gnus-article-hide-text-type
               (1- (point)) (1+ (point)) 'overstrike)
              (put-text-property
               (- (point) 2) (1- (point)) 'face 'underline))
             ((eq previous ?_)
              (gnus-article-hide-text-type (- (point) 2) (point) 'overstrike)
              (put-text-property
               (point) (1+ (point)) 'face 'underline)))))))))

(defun article-fill-long-lines ()
  "Fill lines that are wider than the window width."
  (interactive)
  (save-excursion
    (let ((buffer-read-only nil)
          (width (window-width (get-buffer-window (current-buffer)))))
      (save-restriction
        (article-goto-body)
        (let ((adaptive-fill-mode nil))
          (while (not (eobp))
            (end-of-line)
            (when (>= (current-column) (min fill-column width))
              (narrow-to-region (point) (gnus-point-at-bol))
              (fill-paragraph nil)
              (goto-char (point-max))
              (widen))
            (forward-line 1)))))))

(defun article-capitalize-sentences ()
  "Capitalize the first word in each sentence."
  (interactive)
  (save-excursion
    (let ((buffer-read-only nil)
          (paragraph-start "^[\n\^L]"))
      (article-goto-body)
      (while (not (eobp))
        (capitalize-word 1)
        (forward-sentence)))))

(defun article-remove-cr ()
  "Remove trailing CRs and then translate remaining CRs into LFs."
  (interactive)
  (save-excursion
    (let ((buffer-read-only nil))
      (goto-char (point-min))
      (while (re-search-forward "\r+$" nil t)
        (replace-match "" t t))
      (goto-char (point-min))
      (while (search-forward "\r" nil t)
        (replace-match "\n" t t)))))

(defun article-remove-trailing-blank-lines ()
  "Remove all trailing blank lines from the article."
  (interactive)
  (save-excursion
    (let ((buffer-read-only nil))
      (goto-char (point-max))
      (delete-region
       (point)
       (progn
         (while (and (not (bobp))
                     (looking-at "^[ \t]*$")
                     (not (gnus-annotation-in-region-p
                           (point) (gnus-point-at-eol))))
           (forward-line -1))
         (forward-line 1)
         (point))))))

(defun article-display-x-face (&optional force)
  "Look for an X-Face header and display it if present."
  (interactive (list 'force))
  (save-excursion
    ;; Delete the old process, if any.
    (when (process-status "article-x-face")
      (delete-process "article-x-face"))
    (let ((inhibit-point-motion-hooks t)
          (case-fold-search t)
          from last)
      (save-restriction
        (article-narrow-to-head)
        (goto-char (point-min))
        (setq from (message-fetch-field "from"))
        (goto-char (point-min))
        (while (and gnus-article-x-face-command
                    (not last)
                    (or force
                        ;; Check whether this face is censored.
                        (not gnus-article-x-face-too-ugly)
                        (and gnus-article-x-face-too-ugly from
                             (not (string-match gnus-article-x-face-too-ugly
                                                from))))
                    ;; Has to be present.
                    (re-search-forward "^X-Face: " nil t))
          ;; This used to try to do multiple faces (`while' instead of
          ;; `when' above), but (a) sending multiple EOFs to xv doesn't
          ;; work (b) it can crash some versions of Emacs (c) are
          ;; multiple faces really something to encourage?
          (when (stringp gnus-article-x-face-command)
            (setq last t))
          ;; We now have the area of the buffer where the X-Face is stored.
          (save-excursion
            (let ((beg (point))
                  (end (1- (re-search-forward "^\\($\\|[^ \t]\\)" nil t))))
              ;; We display the face.
              (if (symbolp gnus-article-x-face-command)
                  ;; The command is a lisp function, so we call it.
                  (if (gnus-functionp gnus-article-x-face-command)
                      (funcall gnus-article-x-face-command beg end)
                    (error "%s is not a function" gnus-article-x-face-command))
                ;; The command is a string, so we interpret the command
                ;; as a, well, command, and fork it off.
                (let ((process-connection-type nil))
                  (process-kill-without-query
                   (start-process
                    "article-x-face" nil shell-file-name shell-command-switch
                    gnus-article-x-face-command))
                  (process-send-region "article-x-face" beg end)
                  (process-send-eof "article-x-face"))))))))))

(defun article-decode-mime-words ()
  "Decode all MIME-encoded words in the article."
  (interactive)
  (save-excursion
    (set-buffer gnus-article-buffer)
    (let ((inhibit-point-motion-hooks t)
          buffer-read-only
          (mail-parse-charset gnus-newsgroup-charset)
          (mail-parse-ignored-charsets 
           (save-excursion (set-buffer gnus-summary-buffer)
                           gnus-newsgroup-ignored-charsets)))
      (mail-decode-encoded-word-region (point-min) (point-max)))))

(defun article-decode-charset (&optional prompt)
  "Decode charset-encoded text in the article.
If PROMPT (the prefix), prompt for a coding system to use."
  (interactive "P")
  (let ((inhibit-point-motion-hooks t) (case-fold-search t)
        buffer-read-only
        (mail-parse-charset gnus-newsgroup-charset)
        (mail-parse-ignored-charsets 
         (save-excursion (condition-case nil
                             (set-buffer gnus-summary-buffer)
                           (error))
                         gnus-newsgroup-ignored-charsets))
        ct cte ctl charset format)
  (save-excursion
    (save-restriction
      (article-narrow-to-head)
      (setq ct (message-fetch-field "Content-Type" t)
            cte (message-fetch-field "Content-Transfer-Encoding" t)
            ctl (and ct (ignore-errors
                          (mail-header-parse-content-type ct)))
            charset (cond
                     (prompt
                      (mm-read-coding-system "Charset to decode: "))
                     (ctl
                      (mail-content-type-get ctl 'charset)))
            format (and ctl (mail-content-type-get ctl 'format)))
      (when cte
        (setq cte (mail-header-strip cte)))
      (if (and ctl (not (string-match "/" (car ctl)))) 
          (setq ctl nil))
      (goto-char (point-max)))
    (forward-line 1)
    (save-restriction
      (narrow-to-region (point) (point-max))
      (when (and (or (not ctl)
                     (equal (car ctl) "text/plain"))
                 (not format)) ;; article with format will decode later.
        (mm-decode-body
         charset (and cte (intern (downcase
                                   (gnus-strip-whitespace cte))))
         (car ctl)))))))

(defun article-decode-encoded-words ()
  "Remove encoded-word encoding from headers."
  (let ((inhibit-point-motion-hooks t)
        (mail-parse-charset gnus-newsgroup-charset)
        (mail-parse-ignored-charsets 
         (save-excursion (condition-case nil
                             (set-buffer gnus-summary-buffer)
                           (error))
                         gnus-newsgroup-ignored-charsets))
        buffer-read-only)
    (save-restriction
      (article-narrow-to-head)
      (funcall gnus-decode-header-function (point-min) (point-max)))))

(defun article-de-quoted-unreadable (&optional force)
  "Translate a quoted-printable-encoded article.
If FORCE, decode the article whether it is marked as quoted-printable
or not."
  (interactive (list 'force))
  (save-excursion
    (let ((buffer-read-only nil)
          (type (gnus-fetch-field "content-transfer-encoding"))
          (charset gnus-newsgroup-charset))
      (when (or force
                (and type (string-match "quoted-printable" (downcase type))))
        (article-goto-body)
        (quoted-printable-decode-region (point) (point-max) charset)))))

(defun article-de-base64-unreadable (&optional force)
  "Translate a base64 article.
If FORCE, decode the article whether it is marked as base64 not."
  (interactive (list 'force))
  (save-excursion
    (let ((buffer-read-only nil)
          (type (gnus-fetch-field "content-transfer-encoding"))
          (charset gnus-newsgroup-charset))
      (when (or force
                (and type (string-match "quoted-printable" (downcase type))))
        (article-goto-body)
        (save-restriction
          (narrow-to-region (point) (point-max))
          (base64-decode-region (point-min) (point-max))
          (if (mm-coding-system-p charset)
              (mm-decode-coding-region (point-min) (point-max) charset)))))))

(eval-when-compile
  (require 'rfc1843))

(defun article-decode-HZ ()
  "Translate a HZ-encoded article."
  (interactive)
  (require 'rfc1843)
  (save-excursion
    (let ((buffer-read-only nil))
      (rfc1843-decode-region (point-min) (point-max)))))

(defun article-wash-html ()
  "Format an html article."
  (interactive)
  (save-excursion
    (let ((buffer-read-only nil)
          (charset gnus-newsgroup-charset))
      (article-goto-body)
      (save-window-excursion
        (save-restriction
          (narrow-to-region (point) (point-max))
          (mm-setup-w3)
          (let ((w3-strict-width (window-width))
                (url-standalone-mode t))
            (condition-case var
                (w3-region (point-min) (point-max))
              (error))))))))

(defun article-hide-list-identifiers ()
  "Remove list identifies from the Subject header.
The `gnus-list-identifiers' variable specifies what to do."
  (interactive)
  (save-excursion
    (save-restriction
      (let ((inhibit-point-motion-hooks t)
            buffer-read-only)
        (article-narrow-to-head)
        (let ((regexp (if (stringp gnus-list-identifiers) gnus-list-identifiers
                        (mapconcat 'identity gnus-list-identifiers " *\\|"))))
          (when regexp
            (goto-char (point-min))
            (when (re-search-forward
                   (concat "^Subject: +\\(\\(\\(Re: +\\)?\\(" regexp 
                           " *\\)\\)+\\(Re: +\\)?\\)")
                   nil t)
              (let ((s (or (match-string 3) (match-string 5))))
                (delete-region (match-beginning 1) (match-end 1))
                (when s
                  (goto-char (match-beginning 1))
                  (insert s))))))))))

(defun article-hide-pgp ()
  "Remove any PGP headers and signatures in the current article."
  (interactive)
  (save-excursion
    (save-restriction
      (let ((inhibit-point-motion-hooks t)
            buffer-read-only beg end)
        (article-goto-body)
        ;; Hide the "header".
        (when (re-search-forward "^-----BEGIN PGP SIGNED MESSAGE-----\n" nil t)
          (push 'pgp gnus-article-wash-types)
          (delete-region (match-beginning 0) (match-end 0))
          ;; Remove armor headers (rfc2440 6.2)
          (delete-region (point) (or (re-search-forward "^[ \t]*\n" nil t)
                                     (point)))
          (setq beg (point))
          ;; Hide the actual signature.
          (and (search-forward "\n-----BEGIN PGP SIGNATURE-----\n" nil t)
               (setq end (1+ (match-beginning 0)))
               (delete-region
                end
                (if (search-forward "\n-----END PGP SIGNATURE-----\n" nil t)
                    (match-end 0)
                  ;; Perhaps we shouldn't hide to the end of the buffer
                  ;; if there is no end to the signature?
                  (point-max))))
          ;; Hide "- " PGP quotation markers.
          (when (and beg end)
            (narrow-to-region beg end)
            (goto-char (point-min))
            (while (re-search-forward "^- " nil t)
              (delete-region
               (match-beginning 0) (match-end 0)))
            (widen))
          (gnus-run-hooks 'gnus-article-hide-pgp-hook))))))

(defun article-hide-pem (&optional arg)
  "Toggle hiding of any PEM headers and signatures in the current article.
If given a negative prefix, always show; if given a positive prefix,
always hide."
  (interactive (gnus-article-hidden-arg))
  (unless (gnus-article-check-hidden-text 'pem arg)
    (save-excursion
      (let (buffer-read-only end)
        (goto-char (point-min))
        ;; Hide the horrendously ugly "header".
        (when (and (search-forward
                    "\n-----BEGIN PRIVACY-ENHANCED MESSAGE-----\n"
                    nil t)
                   (setq end (1+ (match-beginning 0))))
          (push 'pem gnus-article-wash-types)
          (gnus-article-hide-text-type
           end
           (if (search-forward "\n\n" nil t)
               (match-end 0)
             (point-max))
           'pem)
          ;; Hide the trailer as well
          (when (search-forward "\n-----END PRIVACY-ENHANCED MESSAGE-----\n"
                                nil t)
            (gnus-article-hide-text-type
             (match-beginning 0) (match-end 0) 'pem)))))))

(defun article-strip-banner ()
  "Strip the banner specified by the `banner' group parameter."
  (interactive)
  (save-excursion
    (save-restriction
      (let ((inhibit-point-motion-hooks t)
            (banner (gnus-group-get-parameter gnus-newsgroup-name 'banner))
            (gnus-signature-limit nil)
            buffer-read-only beg end)
        (when banner
          (article-goto-body)
          (cond
           ((eq banner 'signature)
            (when (gnus-article-narrow-to-signature)
              (widen)
              (forward-line -1)
              (delete-region (point) (point-max))))
           ((stringp banner)
            (while (re-search-forward banner nil t)
              (delete-region (match-beginning 0) (match-end 0))))))))))

(defun article-babel ()
  "Translate article using an online translation service."
  (interactive)
  (require 'babel)
  (save-excursion
    (set-buffer gnus-article-buffer)
    (when (article-goto-body)
      (let* ((buffer-read-only nil)
             (start (point))
             (end (point-max))
             (orig (buffer-substring start end))
             (trans (babel-as-string orig)))
        (save-restriction
          (narrow-to-region start end)
          (delete-region start end)
          (insert trans))))))

(defun article-hide-signature (&optional arg)
  "Hide the signature in the current article.
If given a negative prefix, always show; if given a positive prefix,
always hide."
  (interactive (gnus-article-hidden-arg))
  (unless (gnus-article-check-hidden-text 'signature arg)
    (save-excursion
      (save-restriction
        (let ((buffer-read-only nil))
          (when (gnus-article-narrow-to-signature)
            (gnus-article-hide-text-type
             (point-min) (point-max) 'signature)))))))

(defun article-strip-headers-in-body ()
  "Strip offensive headers from bodies."
  (interactive)
  (save-excursion
    (article-goto-body)
    (let ((case-fold-search t))
      (when (looking-at "x-no-archive:")
        (gnus-delete-line)))))

(defun article-strip-leading-blank-lines ()
  "Remove all blank lines from the beginning of the article."
  (interactive)
  (save-excursion
    (let ((inhibit-point-motion-hooks t)
          buffer-read-only)
      (when (article-goto-body)
        (while (and (not (eobp))
                    (looking-at "[ \t]*$"))
          (gnus-delete-line))))))

(defun article-narrow-to-head ()
  "Narrow the buffer to the head of the message.
Point is left at the beginning of the narrowed-to region."
  (narrow-to-region
   (goto-char (point-min))
   (if (search-forward "\n\n" nil 1)
       (1- (point))
     (point-max)))
  (goto-char (point-min)))

(defun article-goto-body ()
  "Place point at the start of the body."
  (goto-char (point-min))
  (cond
   ;; This variable is only bound when dealing with separate
   ;; MIME body parts.
   (article-goto-body-goes-to-point-min-p
    t)
   ((search-forward "\n\n" nil t)
    t)
   (t
    (goto-char (point-max))
    nil)))

(defun article-strip-multiple-blank-lines ()
  "Replace consecutive blank lines with one empty line."
  (interactive)
  (save-excursion
    (let ((inhibit-point-motion-hooks t)
          buffer-read-only)
      ;; First make all blank lines empty.
      (article-goto-body)
      (while (re-search-forward "^[ \t]+$" nil t)
        (unless (gnus-annotation-in-region-p
                 (match-beginning 0) (match-end 0))
          (replace-match "" nil t)))
      ;; Then replace multiple empty lines with a single empty line.
      (article-goto-body)
      (while (re-search-forward "\n\n\n+" nil t)
        (unless (gnus-annotation-in-region-p
                 (match-beginning 0) (match-end 0))
          (replace-match "\n\n" t t))))))

(defun article-strip-leading-space ()
  "Remove all white space from the beginning of the lines in the article."
  (interactive)
  (save-excursion
    (let ((inhibit-point-motion-hooks t)
          buffer-read-only)
      (article-goto-body)
      (while (re-search-forward "^[ \t]+" nil t)
        (replace-match "" t t)))))

(defun article-strip-trailing-space ()
  "Remove all white space from the end of the lines in the article."
  (interactive)
  (save-excursion
    (let ((inhibit-point-motion-hooks t)
          buffer-read-only)
      (article-goto-body)
      (while (re-search-forward "[ \t]+$" nil t)
        (replace-match "" t t)))))

(defun article-strip-blank-lines ()
  "Strip leading, trailing and multiple blank lines."
  (interactive)
  (article-strip-leading-blank-lines)
  (article-remove-trailing-blank-lines)
  (article-strip-multiple-blank-lines))

(defun article-strip-all-blank-lines ()
  "Strip all blank lines."
  (interactive)
  (save-excursion
    (let ((inhibit-point-motion-hooks t)
          buffer-read-only)
      (article-goto-body)
      (while (re-search-forward "^[ \t]*\n" nil t)
        (replace-match "" t t)))))

(defun gnus-article-narrow-to-signature ()
  "Narrow to the signature; return t if a signature is found, else nil."
  (let ((inhibit-point-motion-hooks t))
    (when (gnus-article-search-signature)
      (forward-line 1)
      ;; Check whether we have some limits to what we consider
      ;; to be a signature.
      (let ((limits (if (listp gnus-signature-limit) gnus-signature-limit
                      (list gnus-signature-limit)))
            limit limited)
        (while (setq limit (pop limits))
          (if (or (and (integerp limit)
                       (< (- (point-max) (point)) limit))
                  (and (floatp limit)
                       (< (count-lines (point) (point-max)) limit))
                  (and (gnus-functionp limit)
                       (funcall limit))
                  (and (stringp limit)
                       (not (re-search-forward limit nil t))))
              ()                        ; This limit did not succeed.
            (setq limited t
                  limits nil)))
        (unless limited
          (narrow-to-region (point) (point-max))
          t)))))

(defun gnus-article-search-signature ()
  "Search the current buffer for the signature separator.
Put point at the beginning of the signature separator."
  (let ((cur (point)))
    (goto-char (point-max))
    (if (if (stringp gnus-signature-separator)
            (re-search-backward gnus-signature-separator nil t)
          (let ((seps gnus-signature-separator))
            (while (and seps
                        (not (re-search-backward (car seps) nil t)))
              (pop seps))
            seps))
        t
      (goto-char cur)
      nil)))

(defun gnus-article-hidden-arg ()
  "Return the current prefix arg as a number, or 0 if no prefix."
  (list (if current-prefix-arg
            (prefix-numeric-value current-prefix-arg)
          0)))

(defun gnus-article-check-hidden-text (type arg)
  "Return nil if hiding is necessary.
Arg can be nil or a number.  Nil and positive means hide, negative
means show, 0 means toggle."
  (save-excursion
    (save-restriction
      (let ((hide (gnus-article-hidden-text-p type)))
        (cond
         ((or (null arg)
              (> arg 0))
          nil)
         ((< arg 0)
          (gnus-article-show-hidden-text type))
         (t
          (if (eq hide 'hidden)
              (gnus-article-show-hidden-text type)
            nil)))))))

(defun gnus-article-hidden-text-p (type)
  "Say whether the current buffer contains hidden text of type TYPE."
  (let ((pos (text-property-any (point-min) (point-max) 'article-type type)))
    (while (and pos
                (not (get-text-property pos 'invisible))
                (not (get-text-property pos 'dummy-invisible)))
      (setq pos
            (text-property-any (1+ pos) (point-max) 'article-type type)))
    (if pos
        'hidden
      nil)))

(defun gnus-article-show-hidden-text (type &optional hide)
  "Show all hidden text of type TYPE.
If HIDE, hide the text instead."
  (save-excursion
    (let ((buffer-read-only nil)
          (inhibit-point-motion-hooks t)
          (end (point-min))
          beg)
      (while (setq beg (text-property-any end (point-max) 'article-type type))
        (goto-char beg)
        (setq end (or
                   (text-property-not-all beg (point-max) 'article-type type)
                   (point-max)))
        (if hide
            (gnus-article-hide-text beg end gnus-hidden-properties)
          (gnus-article-unhide-text beg end))
        (goto-char end))
      t)))

(defconst article-time-units
  `((year . ,(* 365.25 24 60 60))
    (week . ,(* 7 24 60 60))
    (day . ,(* 24 60 60))
    (hour . ,(* 60 60))
    (minute . 60)
    (second . 1))
  "Mapping from time units to seconds.")

(defun article-date-ut (&optional type highlight header)
  "Convert DATE date to universal time in the current article.
If TYPE is `local', convert to local time; if it is `lapsed', output
how much time has lapsed since DATE.  For `lapsed', the value of
`gnus-article-date-lapsed-new-header' says whether the \"X-Sent:\" header
should replace the \"Date:\" one, or should be added below it."
  (interactive (list 'ut t))
  (let* ((header (or header
                     (message-fetch-field "date")
                     ""))
         (tdate-regexp "^Date:[ \t]\\|^X-Sent:[ \t]")
         (date-regexp
          (cond
           ((not gnus-article-date-lapsed-new-header)
            tdate-regexp)
           ((eq type 'lapsed)
            "^X-Sent:[ \t]")
           (t
            "^Date:[ \t]")))
         (date (if (vectorp header) (mail-header-date header)
                 header))
         (inhibit-point-motion-hooks t)
         pos
         bface eface)
    (save-excursion
      (save-restriction
        (article-narrow-to-head)
        (when (re-search-forward tdate-regexp nil t)
          (setq bface (get-text-property (gnus-point-at-bol) 'face)
                date (or (get-text-property (gnus-point-at-bol)
                                            'original-date)
                         date)
                eface (get-text-property (1- (gnus-point-at-eol)) 'face))
          (forward-line 1))
        (when (and date (not (string= date "")))
          (goto-char (point-min))
          (let ((buffer-read-only nil))
            ;; Delete any old Date headers.
            (while (re-search-forward date-regexp nil t)
              (if pos
                  (delete-region (progn (beginning-of-line) (point))
                                 (progn (forward-line 1) (point)))
                (delete-region (progn (beginning-of-line) (point))
                               (progn (end-of-line) (point)))
                (setq pos (point))))
            (when (and (not pos) (re-search-forward tdate-regexp nil t))
              (forward-line 1))
            (if pos (goto-char pos))
            (insert (article-make-date-line date (or type 'ut)))
            (when (not pos)
              (insert "\n")
              (forward-line -1))
            ;; Do highlighting.
            (beginning-of-line)
            (when (looking-at "\\([^:]+\\): *\\(.*\\)$")
              (put-text-property (match-beginning 1) (1+ (match-end 1))
                                 'original-date date)
              (put-text-property (match-beginning 1) (1+ (match-end 1))
                                 'face bface)
              (put-text-property (match-beginning 2) (match-end 2)
                                 'face eface))))))))

(defun article-make-date-line (date type)
  "Return a DATE line of TYPE."
  (let ((time (condition-case ()
                  (date-to-time date)
                (error '(0 0)))))
    (cond
     ;; Convert to the local timezone.  We have to slap a
     ;; `condition-case' round the calls to the timezone
     ;; functions since they aren't particularly resistant to
     ;; buggy dates.
     ((eq type 'local)
      (let ((tz (car (current-time-zone time))))
        (format "Date: %s %s%02d%02d" (current-time-string time)
                (if (> tz 0) "+" "-") (/ (abs tz) 3600) 
                (/ (% (abs tz) 3600) 60))))
     ;; Convert to Universal Time.
     ((eq type 'ut)
      (concat "Date: "
              (current-time-string
               (let* ((e (parse-time-string date))
                      (tm (apply 'encode-time e))
                      (ms (car tm))
                      (ls (- (cadr tm) (car (current-time-zone time)))))
                 (cond ((< ls 0) (list (1- ms) (+ ls 65536)))
                       ((> ls 65535) (list (1+ ms) (- ls 65536)))
                       (t (list ms ls)))))
              " UT"))
     ;; Get the original date from the article.
     ((eq type 'original)
      (concat "Date: " (if (string-match "\n+$" date)
                           (substring date 0 (match-beginning 0))
                         date)))
     ;; Let the user define the format.
     ((eq type 'user)
      (if (gnus-functionp gnus-article-time-format)
          (funcall gnus-article-time-format time)
        (concat
         "Date: "
         (format-time-string gnus-article-time-format time))))
     ;; ISO 8601.
     ((eq type 'iso8601)
      (let ((tz (car (current-time-zone time))))
        (concat
         "Date: "
         (format-time-string "%Y%m%dT%H%M%S" time)
         (format "%s%02d%02d"
                 (if (> tz 0) "+" "-") (/ (abs tz) 3600) 
                 (/ (% (abs tz) 3600) 60)))))
     ;; Do an X-Sent lapsed format.
     ((eq type 'lapsed)
      ;; If the date is seriously mangled, the timezone functions are
      ;; liable to bug out, so we ignore all errors.
      (let* ((now (current-time))
             (real-time (subtract-time now time))
             (real-sec (and real-time
                            (+ (* (float (car real-time)) 65536)
                               (cadr real-time))))
             (sec (and real-time (abs real-sec)))
             num prev)
        (cond
         ((null real-time)
          "X-Sent: Unknown")
         ((zerop sec)
          "X-Sent: Now")
         (t
          (concat
           "X-Sent: "
           ;; This is a bit convoluted, but basically we go
           ;; through the time units for years, weeks, etc,
           ;; and divide things to see whether that results
           ;; in positive answers.
           (mapconcat
            (lambda (unit)
              (if (zerop (setq num (ffloor (/ sec (cdr unit)))))
                  ;; The (remaining) seconds are too few to
                  ;; be divided into this time unit.
                  ""
                ;; It's big enough, so we output it.
                (setq sec (- sec (* num (cdr unit))))
                (prog1
                    (concat (if prev ", " "") (int-to-string
                                               (floor num))
                            " " (symbol-name (car unit))
                            (if (> num 1) "s" ""))
                  (setq prev t))))
            article-time-units "")
           ;; If dates are odd, then it might appear like the
           ;; article was sent in the future.
           (if (> real-sec 0)
               " ago"
             " in the future"))))))
     (t
      (error "Unknown conversion type: %s" type)))))

(defun article-date-local (&optional highlight)
  "Convert the current article date to the local timezone."
  (interactive (list t))
  (article-date-ut 'local highlight))

(defun article-date-original (&optional highlight)
  "Convert the current article date to what it was originally.
This is only useful if you have used some other date conversion
function and want to see what the date was before converting."
  (interactive (list t))
  (article-date-ut 'original highlight))

(defun article-date-lapsed (&optional highlight)
  "Convert the current article date to time lapsed since it was sent."
  (interactive (list t))
  (article-date-ut 'lapsed highlight))

(defun article-update-date-lapsed ()
  "Function to be run from a timer to update the lapsed time line."
  (let (deactivate-mark)
    (save-excursion
      (ignore-errors
        (walk-windows
         (lambda (w)
           (set-buffer (window-buffer w))
           (when (eq major-mode 'gnus-article-mode)
             (goto-char (point-min))
             (when (re-search-forward "^X-Sent:" nil t)
               (article-date-lapsed t))))
         nil 'visible)))))

(defun gnus-start-date-timer (&optional n)
  "Start a timer to update the X-Sent header in the article buffers.
The numerical prefix says how frequently (in seconds) the function
is to run."
  (interactive "p")
  (unless n
    (setq n 1))
  (gnus-stop-date-timer)
  (setq article-lapsed-timer
        (nnheader-run-at-time 1 n 'article-update-date-lapsed)))

(defun gnus-stop-date-timer ()
  "Stop the X-Sent timer."
  (interactive)
  (when article-lapsed-timer
    (nnheader-cancel-timer article-lapsed-timer)
    (setq article-lapsed-timer nil)))

(defun article-date-user (&optional highlight)
  "Convert the current article date to the user-defined format.
This format is defined by the `gnus-article-time-format' variable."
  (interactive (list t))
  (article-date-ut 'user highlight))

(defun article-date-iso8601 (&optional highlight)
  "Convert the current article date to ISO8601."
  (interactive (list t))
  (article-date-ut 'iso8601 highlight))

(defun article-show-all ()
  "Show all hidden text in the article buffer."
  (interactive)
  (save-excursion
    (let ((buffer-read-only nil))
      (gnus-article-unhide-text (point-min) (point-max)))))

(defun article-emphasize (&optional arg)
  "Emphasize text according to `gnus-emphasis-alist'."
  (interactive (gnus-article-hidden-arg))
  (unless (gnus-article-check-hidden-text 'emphasis arg)
    (save-excursion
      (let ((alist (or 
                    (condition-case nil
                        (with-current-buffer gnus-summary-buffer 
                          gnus-article-emphasis-alist) 
                      (error))
                    gnus-emphasis-alist))
            (buffer-read-only nil)
            (props (append '(article-type emphasis)
                           gnus-hidden-properties))
            regexp elem beg invisible visible face)
        (article-goto-body)
        (setq beg (point))
        (while (setq elem (pop alist))
          (goto-char beg)
          (setq regexp (car elem)
                invisible (nth 1 elem)
                visible (nth 2 elem)
                face (nth 3 elem))
          (while (re-search-forward regexp nil t)
            (when (and (match-beginning visible) (match-beginning invisible))
              (push 'emphasis gnus-article-wash-types)
              (gnus-article-hide-text
               (match-beginning invisible) (match-end invisible) props)
              (gnus-article-unhide-text-type
               (match-beginning visible) (match-end visible) 'emphasis)
              (gnus-put-text-property-excluding-newlines
               (match-beginning visible) (match-end visible) 'face face)
              (goto-char (match-end invisible)))))))))

(defun gnus-article-setup-highlight-words (&optional highlight-words)
  "Setup newsgroup emphasis alist."
  (unless gnus-article-emphasis-alist
    (let ((name (and gnus-newsgroup-name
                     (gnus-group-real-name gnus-newsgroup-name))))
      (make-local-variable 'gnus-article-emphasis-alist)
      (setq gnus-article-emphasis-alist 
            (nconc 
             (let ((alist gnus-group-highlight-words-alist) elem highlight)
               (while (setq elem (pop alist))
                 (when (and name (string-match (car elem) name))
                   (setq alist nil
                         highlight (copy-sequence (cdr elem)))))
               highlight)
             (copy-sequence highlight-words)
             (if gnus-newsgroup-name
                 (copy-sequence (gnus-group-find-parameter 
                                 gnus-newsgroup-name 'highlight-words t)))
             gnus-emphasis-alist)))))

(defvar gnus-summary-article-menu)
(defvar gnus-summary-post-menu)

;;; Saving functions.

(defun gnus-article-save (save-buffer file &optional num)
  "Save the currently selected article."
  (unless gnus-save-all-headers
    ;; Remove headers according to `gnus-saved-headers'.
    (let ((gnus-visible-headers
           (or gnus-saved-headers gnus-visible-headers))
          (gnus-article-buffer save-buffer))
      (save-excursion
        (set-buffer save-buffer)
        (article-hide-headers 1 t))))
  (save-window-excursion
    (if (not gnus-default-article-saver)
        (error "No default saver is defined")
      ;; !!! Magic!  The saving functions all save
      ;; `gnus-save-article-buffer' (or so they think), but we
      ;; bind that variable to our save-buffer.
      (set-buffer gnus-article-buffer)
      (let* ((gnus-save-article-buffer save-buffer)
             (filename
              (cond
               ((not gnus-prompt-before-saving) 'default)
               ((eq gnus-prompt-before-saving 'always) nil)
               (t file)))
             (gnus-number-of-articles-to-be-saved
              (when (eq gnus-prompt-before-saving t)
                num)))                  ; Magic
        (set-buffer gnus-article-current-summary)
        (funcall gnus-default-article-saver filename)))))

(defun gnus-read-save-file-name (prompt &optional filename
                                        function group headers variable)
  (let ((default-name
          (funcall function group headers (symbol-value variable)))
        result)
    (setq
     result
     (cond
      ((eq filename 'default)
       default-name)
      ((eq filename t)
       default-name)
      (filename filename)
      (t
       (let* ((split-name (gnus-get-split-value gnus-split-methods))
              (prompt
               (format prompt
                       (if (and gnus-number-of-articles-to-be-saved
                                (> gnus-number-of-articles-to-be-saved 1))
                           (format "these %d articles"
                                   gnus-number-of-articles-to-be-saved)
                         "this article")))
              (file
               ;; Let the split methods have their say.
               (cond
                ;; No split name was found.
                ((null split-name)
                 (read-file-name
                  (concat prompt " (default "
                          (file-name-nondirectory default-name) ") ")
                  (file-name-directory default-name)
                  default-name))
                ;; A single group name is returned.
                ((stringp split-name)
                 (setq default-name
                       (funcall function split-name headers
                                (symbol-value variable)))
                 (read-file-name
                  (concat prompt " (default "
                          (file-name-nondirectory default-name) ") ")
                  (file-name-directory default-name)
                  default-name))
                ;; A single split name was found
                ((= 1 (length split-name))
                 (let* ((name (expand-file-name
                               (car split-name) gnus-article-save-directory))
                        (dir (cond ((file-directory-p name)
                                    (file-name-as-directory name))
                                   ((file-exists-p name) name)
                                   (t gnus-article-save-directory))))
                   (read-file-name
                    (concat prompt " (default " name ") ")
                    dir name)))
                ;; A list of splits was found.
                (t
                 (setq split-name (nreverse split-name))
                 (let (result)
                   (let ((file-name-history
                          (nconc split-name file-name-history)))
                     (setq result
                           (expand-file-name
                            (read-file-name
                             (concat prompt " (`M-p' for defaults) ")
                             gnus-article-save-directory
                             (car split-name))
                            gnus-article-save-directory)))
                   (car (push result file-name-history)))))))
         ;; Create the directory.
         (gnus-make-directory (file-name-directory file))
         ;; If we have read a directory, we append the default file name.
         (when (file-directory-p file)
           (setq file (concat (file-name-as-directory file)
                              (file-name-nondirectory default-name))))
         ;; Possibly translate some characters.
         (nnheader-translate-file-chars file)))))
    (gnus-make-directory (file-name-directory result))
    (set variable result)))

(defun gnus-article-archive-name (group)
  "Return the first instance of an \"Archive-name\" in the current buffer."
  (let ((case-fold-search t))
    (when (re-search-forward "archive-name: *\\([^ \n\t]+\\)[ \t]*$" nil t)
      (nnheader-concat gnus-article-save-directory
                       (match-string 1)))))

(defun gnus-article-nndoc-name (group)
  "If GROUP is an nndoc group, return the name of the parent group."
  (when (eq (car (gnus-find-method-for-group group)) 'nndoc)
    (gnus-group-get-parameter group 'save-article-group)))

(defun gnus-summary-save-in-rmail (&optional filename)
  "Append this article to Rmail file.
Optional argument FILENAME specifies file name.
Directory to save to is default to `gnus-article-save-directory'."
  (setq filename (gnus-read-save-file-name
                  "Save %s in rmail file:" filename
                  gnus-rmail-save-name gnus-newsgroup-name
                  gnus-current-headers 'gnus-newsgroup-last-rmail))
  (gnus-eval-in-buffer-window gnus-save-article-buffer
    (save-excursion
      (save-restriction
        (widen)
        (gnus-output-to-rmail filename))))
  filename)

(defun gnus-summary-save-in-mail (&optional filename)
  "Append this article to Unix mail file.
Optional argument FILENAME specifies file name.
Directory to save to is default to `gnus-article-save-directory'."
  (setq filename (gnus-read-save-file-name
                  "Save %s in Unix mail file:" filename
                  gnus-mail-save-name gnus-newsgroup-name
                  gnus-current-headers 'gnus-newsgroup-last-mail))
  (gnus-eval-in-buffer-window gnus-save-article-buffer
    (save-excursion
      (save-restriction
        (widen)
        (if (and (file-readable-p filename)
                 (mail-file-babyl-p filename))
            (rmail-output-to-rmail-file filename t)
          (gnus-output-to-mail filename)))))
  filename)

(defun gnus-summary-save-in-file (&optional filename overwrite)
  "Append this article to file.
Optional argument FILENAME specifies file name.
Directory to save to is default to `gnus-article-save-directory'."
  (setq filename (gnus-read-save-file-name
                  "Save %s in file:" filename
                  gnus-file-save-name gnus-newsgroup-name
                  gnus-current-headers 'gnus-newsgroup-last-file))
  (gnus-eval-in-buffer-window gnus-save-article-buffer
    (save-excursion
      (save-restriction
        (widen)
        (when (and overwrite
                   (file-exists-p filename))
          (delete-file filename))
        (gnus-output-to-file filename))))
  filename)

(defun gnus-summary-write-to-file (&optional filename)
  "Write this article to a file.
Optional argument FILENAME specifies file name.
The directory to save in defaults to `gnus-article-save-directory'."
  (gnus-summary-save-in-file nil t))

(defun gnus-summary-save-body-in-file (&optional filename)
  "Append this article body to a file.
Optional argument FILENAME specifies file name.
The directory to save in defaults to `gnus-article-save-directory'."
  (setq filename (gnus-read-save-file-name
                  "Save %s body in file:" filename
                  gnus-file-save-name gnus-newsgroup-name
                  gnus-current-headers 'gnus-newsgroup-last-file))
  (gnus-eval-in-buffer-window gnus-save-article-buffer
    (save-excursion
      (save-restriction
        (widen)
        (when (article-goto-body)
          (narrow-to-region (point) (point-max)))
        (gnus-output-to-file filename))))
  filename)

(defun gnus-summary-save-in-pipe (&optional command)
  "Pipe this article to subprocess."
  (setq command
        (cond ((and (eq command 'default)
                    gnus-last-shell-command)
               gnus-last-shell-command)
              (command command)
              (t (read-string
                  (format
                   "Shell command on %s: "
                   (if (and gnus-number-of-articles-to-be-saved
                            (> gnus-number-of-articles-to-be-saved 1))
                       (format "these %d articles"
                               gnus-number-of-articles-to-be-saved)
                     "this article"))
                  gnus-last-shell-command))))
  (when (string-equal command "")
    (setq command gnus-last-shell-command))
  (gnus-eval-in-buffer-window gnus-article-buffer
    (save-restriction
      (widen)
      (shell-command-on-region (point-min) (point-max) command nil)))
  (setq gnus-last-shell-command command))

;;; Article file names when saving.

(defun gnus-capitalize-newsgroup (newsgroup)
  "Capitalize NEWSGROUP name."
  (when (not (zerop (length newsgroup)))
    (concat (char-to-string (upcase (aref newsgroup 0)))
            (substring newsgroup 1))))

(defun gnus-Numeric-save-name (newsgroup headers &optional last-file)
  "Generate file name from NEWSGROUP, HEADERS, and optional LAST-FILE.
If variable `gnus-use-long-file-name' is non-nil, it is ~/News/News.group/num.
Otherwise, it is like ~/News/news/group/num."
  (let ((default
          (expand-file-name
           (concat (if (gnus-use-long-file-name 'not-save)
                       (gnus-capitalize-newsgroup newsgroup)
                     (gnus-newsgroup-directory-form newsgroup))
                   "/" (int-to-string (mail-header-number headers)))
           gnus-article-save-directory)))
    (if (and last-file
             (string-equal (file-name-directory default)
                           (file-name-directory last-file))
             (string-match "^[0-9]+$" (file-name-nondirectory last-file)))
        default
      (or last-file default))))

(defun gnus-numeric-save-name (newsgroup headers &optional last-file)
  "Generate file name from NEWSGROUP, HEADERS, and optional LAST-FILE.
If variable `gnus-use-long-file-name' is non-nil, it is
~/News/news.group/num.  Otherwise, it is like ~/News/news/group/num."
  (let ((default
          (expand-file-name
           (concat (if (gnus-use-long-file-name 'not-save)
                       newsgroup
                     (gnus-newsgroup-directory-form newsgroup))
                   "/" (int-to-string (mail-header-number headers)))
           gnus-article-save-directory)))
    (if (and last-file
             (string-equal (file-name-directory default)
                           (file-name-directory last-file))
             (string-match "^[0-9]+$" (file-name-nondirectory last-file)))
        default
      (or last-file default))))

(defun gnus-Plain-save-name (newsgroup headers &optional last-file)
  "Generate file name from NEWSGROUP, HEADERS, and optional LAST-FILE.
If variable `gnus-use-long-file-name' is non-nil, it is
~/News/News.group.  Otherwise, it is like ~/News/news/group/news."
  (or last-file
      (expand-file-name
       (if (gnus-use-long-file-name 'not-save)
           (gnus-capitalize-newsgroup newsgroup)
         (concat (gnus-newsgroup-directory-form newsgroup) "/news"))
       gnus-article-save-directory)))

(defun gnus-plain-save-name (newsgroup headers &optional last-file)
  "Generate file name from NEWSGROUP, HEADERS, and optional LAST-FILE.
If variable `gnus-use-long-file-name' is non-nil, it is
~/News/news.group.  Otherwise, it is like ~/News/news/group/news."
  (or last-file
      (expand-file-name
       (if (gnus-use-long-file-name 'not-save)
           newsgroup
         (concat (gnus-newsgroup-directory-form newsgroup) "/news"))
       gnus-article-save-directory)))

(eval-and-compile
  (mapcar
   (lambda (func)
     (let (afunc gfunc)
       (if (consp func)
           (setq afunc (car func)
                 gfunc (cdr func))
         (setq afunc func
               gfunc (intern (format "gnus-%s" func))))
       (defalias gfunc
         (if (fboundp afunc)
           `(lambda (&optional interactive &rest args)
              ,(documentation afunc t)
              (interactive (list t))
              (save-excursion
                (set-buffer gnus-article-buffer)
                (if interactive
                    (call-interactively ',afunc)
                  (apply ',afunc args))))))))
   '(article-hide-headers
     article-hide-boring-headers
     article-treat-overstrike
     article-fill-long-lines
     article-capitalize-sentences
     article-remove-cr
     article-display-x-face
     article-de-quoted-unreadable
     article-de-base64-unreadable
     article-decode-HZ
     article-wash-html
     article-mime-decode-quoted-printable
     article-hide-list-identifiers
     article-hide-pgp
     article-strip-banner
     article-babel
     article-hide-pem
     article-hide-signature
     article-strip-headers-in-body
     article-remove-trailing-blank-lines
     article-strip-leading-blank-lines
     article-strip-multiple-blank-lines
     article-strip-leading-space
     article-strip-trailing-space
     article-strip-blank-lines
     article-strip-all-blank-lines
     article-date-local
     article-date-iso8601
     article-date-original
     article-date-ut
     article-decode-mime-words
     article-decode-charset
     article-decode-encoded-words
     article-date-user
     article-date-lapsed
     article-emphasize
     article-treat-dumbquotes
     article-normalize-headers
     (article-show-all . gnus-article-show-all-headers))))
\f
;;;
;;; Gnus article mode
;;;

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

(set-keymap-parent gnus-article-mode-map widget-keymap)

(gnus-define-keys gnus-article-mode-map
  " " gnus-article-goto-next-page
  "\177" gnus-article-goto-prev-page
  [delete] gnus-article-goto-prev-page
  [backspace] gnus-article-goto-prev-page
  "\C-c^" gnus-article-refer-article
  "h" gnus-article-show-summary
  "s" gnus-article-show-summary
  "\C-c\C-m" gnus-article-mail
  "?" gnus-article-describe-briefly
  "e" gnus-summary-edit-article
  "<" beginning-of-buffer
  ">" end-of-buffer
  "\C-c\C-i" gnus-info-find-node
  "\C-c\C-b" gnus-bug

  "\C-d" gnus-article-read-summary-keys
  "\M-*" gnus-article-read-summary-keys
  "\M-#" gnus-article-read-summary-keys
  "\M-^" gnus-article-read-summary-keys
  "\M-g" gnus-article-read-summary-keys)

(substitute-key-definition
 'undefined 'gnus-article-read-summary-keys gnus-article-mode-map)

(defun gnus-article-make-menu-bar ()
  (gnus-turn-off-edit-menu 'article)
  (unless (boundp 'gnus-article-article-menu)
    (easy-menu-define
     gnus-article-article-menu gnus-article-mode-map ""
     '("Article"
       ["Scroll forwards" gnus-article-goto-next-page t]
       ["Scroll backwards" gnus-article-goto-prev-page t]
       ["Show summary" gnus-article-show-summary t]
       ["Fetch Message-ID at point" gnus-article-refer-article t]
       ["Mail to address at point" gnus-article-mail t]
       ["Send a bug report" gnus-bug t]))

    (easy-menu-define
     gnus-article-treatment-menu gnus-article-mode-map ""
     '("Treatment"
       ["Hide headers" gnus-article-hide-headers t]
       ["Hide signature" gnus-article-hide-signature t]
       ["Hide citation" gnus-article-hide-citation t]
       ["Treat overstrike" gnus-article-treat-overstrike t]
       ["Remove carriage return" gnus-article-remove-cr t]
       ["Remove quoted-unreadable" gnus-article-de-quoted-unreadable t]
       ["Remove base64" gnus-article-de-base64-unreadable t]
       ["Treat html" gnus-article-wash-html t]
       ["Decode HZ" gnus-article-decode-HZ t]))

    ;; Note "Commands" menu is defined in gnus-sum.el for consistency

    (when (boundp 'gnus-summary-post-menu)
      (define-key gnus-article-mode-map [menu-bar post]
        (cons "Post" gnus-summary-post-menu)))

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

(defun gnus-article-mode ()
  "Major mode for displaying an article.

All normal editing commands are switched off.

The following commands are available in addition to all summary mode
commands:
\\<gnus-article-mode-map>
\\[gnus-article-next-page]\t Scroll the article one page forwards
\\[gnus-article-prev-page]\t Scroll the article one page backwards
\\[gnus-article-refer-article]\t Go to the article referred to by an article id near point
\\[gnus-article-show-summary]\t Display the summary buffer
\\[gnus-article-mail]\t Send a reply to the address near point
\\[gnus-article-describe-briefly]\t Describe the current mode briefly
\\[gnus-info-find-node]\t Go to the Gnus info node"
  (interactive)
  (when (gnus-visual-p 'article-menu 'menu)
    (gnus-article-make-menu-bar))
  (gnus-simplify-mode-line)
  (setq mode-name "Article")
  (setq major-mode 'gnus-article-mode)
  (make-local-variable 'minor-mode-alist)
  (use-local-map gnus-article-mode-map)
  (gnus-update-format-specifications nil 'article-mode)
  (set (make-local-variable 'page-delimiter) gnus-page-delimiter)
  (make-local-variable 'gnus-page-broken)
  (make-local-variable 'gnus-button-marker-list)
  (make-local-variable 'gnus-article-current-summary)
  (make-local-variable 'gnus-article-mime-handles)
  (make-local-variable 'gnus-article-decoded-p)
  (make-local-variable 'gnus-article-mime-handle-alist)
  (make-local-variable 'gnus-article-wash-types)
  (gnus-set-default-directory)
  (buffer-disable-undo)
  (setq buffer-read-only t)
  (set-syntax-table gnus-article-mode-syntax-table)
  (mm-enable-multibyte)
  (gnus-run-hooks 'gnus-article-mode-hook))

(defun gnus-article-setup-buffer ()
  "Initialize the article buffer."
  (let* ((name (if gnus-single-article-buffer "*Article*"
                 (concat "*Article " gnus-newsgroup-name "*")))
         (original
          (progn (string-match "\\*Article" name)
                 (concat " *Original Article"
                         (substring name (match-end 0))))))
    (setq gnus-article-buffer name)
    (setq gnus-original-article-buffer original)
    (setq gnus-article-mime-handle-alist nil)
    ;; This might be a variable local to the summary buffer.
    (unless gnus-single-article-buffer
      (save-excursion
        (set-buffer gnus-summary-buffer)
        (setq gnus-article-buffer name)
        (setq gnus-original-article-buffer original)
        (gnus-set-global-variables)))
    (gnus-article-setup-highlight-words)
    ;; Init original article buffer.
    (save-excursion
      (set-buffer (gnus-get-buffer-create gnus-original-article-buffer))
      (mm-enable-multibyte)
      (setq major-mode 'gnus-original-article-mode)
      (make-local-variable 'gnus-original-article))
    (if (get-buffer name)
        (save-excursion
          (set-buffer name)
          (when gnus-article-mime-handles
            (mm-destroy-parts gnus-article-mime-handles))
          (buffer-disable-undo)
          (setq buffer-read-only t)
          (unless (eq major-mode 'gnus-article-mode)
            (gnus-article-mode))
          (current-buffer))
      (save-excursion
        (set-buffer (gnus-get-buffer-create name))
        (gnus-article-mode)
        (make-local-variable 'gnus-summary-buffer)
        (gnus-summary-set-local-parameters gnus-newsgroup-name)
        (current-buffer)))))

;; Set article window start at LINE, where LINE is the number of lines
;; from the head of the article.
(defun gnus-article-set-window-start (&optional line)
  (set-window-start
   (get-buffer-window gnus-article-buffer t)
   (save-excursion
     (set-buffer gnus-article-buffer)
     (goto-char (point-min))
     (if (not line)
         (point-min)
       (gnus-message 6 "Moved to bookmark")
       (search-forward "\n\n" nil t)
       (forward-line line)
       (point)))))

(defun gnus-article-prepare (article &optional all-headers header)
  "Prepare ARTICLE in article mode buffer.
ARTICLE should either be an article number or a Message-ID.
If ARTICLE is an id, HEADER should be the article headers.
If ALL-HEADERS is non-nil, no headers are hidden."
  (save-excursion
    ;; Make sure we start in a summary buffer.
    (unless (eq major-mode 'gnus-summary-mode)
      (set-buffer gnus-summary-buffer))
    (setq gnus-summary-buffer (current-buffer))
    (let* ((gnus-article (if header (mail-header-number header) article))
           (summary-buffer (current-buffer))
           (gnus-tmp-internal-hook gnus-article-internal-prepare-hook)
           (group gnus-newsgroup-name)
           result)
      (save-excursion
        (gnus-article-setup-buffer)
        (set-buffer gnus-article-buffer)
        ;; Deactivate active regions.
        (when (and (boundp 'transient-mark-mode)
                   transient-mark-mode)
          (setq mark-active nil))
        (if (not (setq result (let ((buffer-read-only nil))
                                (gnus-request-article-this-buffer
                                 article group))))
            ;; There is no such article.
            (save-excursion
              (when (and (numberp article)
                         (not (memq article gnus-newsgroup-sparse)))
                (setq gnus-article-current
                      (cons gnus-newsgroup-name article))
                (set-buffer gnus-summary-buffer)
                (setq gnus-current-article article)
                (if (eq (gnus-article-mark article) gnus-undownloaded-mark)
                    (progn
                      (gnus-summary-set-agent-mark article)
                      (message "Message marked for downloading"))
                  (gnus-summary-mark-article article gnus-canceled-mark)
                  (unless (memq article gnus-newsgroup-sparse)
                    (gnus-error 1 "No such article (may have expired or been canceled)")))))
          (if (or (eq result 'pseudo)
                  (eq result 'nneething))
              (progn
                (save-excursion
                  (set-buffer summary-buffer)
                  (push article gnus-newsgroup-history)
                  (setq gnus-last-article gnus-current-article
                        gnus-current-article 0
                        gnus-current-headers nil
                        gnus-article-current nil)
                  (if (eq result 'nneething)
                      (gnus-configure-windows 'summary)
                    (gnus-configure-windows 'article))
                  (gnus-set-global-variables))
                (let ((gnus-article-mime-handle-alist-1
                       gnus-article-mime-handle-alist))
                  (gnus-set-mode-line 'article)))
            ;; The result from the `request' was an actual article -
            ;; or at least some text that is now displayed in the
            ;; article buffer.
            (when (and (numberp article)
                       (not (eq article gnus-current-article)))
              ;; Seems like a new article has been selected.
              ;; `gnus-current-article' must be an article number.
              (save-excursion
                (set-buffer summary-buffer)
                (push article gnus-newsgroup-history)
                (setq gnus-last-article gnus-current-article
                      gnus-current-article article
                      gnus-current-headers
                      (gnus-summary-article-header gnus-current-article)
                      gnus-article-current
                      (cons gnus-newsgroup-name gnus-current-article))
                (unless (vectorp gnus-current-headers)
                  (setq gnus-current-headers nil))
                (gnus-summary-goto-subject gnus-current-article)
                (when (gnus-summary-show-thread)
                  ;; If the summary buffer really was folded, the
                  ;; previous goto may not actually have gone to
                  ;; the right article, but the thread root instead.
                  ;; So we go again.
                  (gnus-summary-goto-subject gnus-current-article))
                (gnus-run-hooks 'gnus-mark-article-hook)
                (gnus-set-mode-line 'summary)
                (when (gnus-visual-p 'article-highlight 'highlight)
                  (gnus-run-hooks 'gnus-visual-mark-article-hook))
                ;; Set the global newsgroup variables here.
                (gnus-set-global-variables)
                (setq gnus-have-all-headers
                      (or all-headers gnus-show-all-headers))))
            (when (or (numberp article)
                      (stringp article))
              (gnus-article-prepare-display)
              ;; Do page break.
              (goto-char (point-min))
              (setq gnus-page-broken
                    (when gnus-break-pages
                      (gnus-narrow-to-page)
                      t)))
            (let ((gnus-article-mime-handle-alist-1
                   gnus-article-mime-handle-alist))
              (gnus-set-mode-line 'article))
            (article-goto-body)
            (set-window-point (get-buffer-window (current-buffer)) (point))
            (gnus-configure-windows 'article)
            t))))))

;;;###autoload
(defun gnus-article-prepare-display ()
  "Make the current buffer look like a nice article."
  ;; Hooks for getting information from the article.
  ;; This hook must be called before being narrowed.
  (let ((gnus-article-buffer (current-buffer))
        buffer-read-only)
    (unless (eq major-mode 'gnus-article-mode)
      (gnus-article-mode))
    (setq buffer-read-only nil
          gnus-article-wash-types nil)
    (gnus-run-hooks 'gnus-tmp-internal-hook)
    (when gnus-display-mime-function
      (funcall gnus-display-mime-function))
    (gnus-run-hooks 'gnus-article-prepare-hook)))

;;;
;;; Gnus MIME viewing functions
;;;

(defvar gnus-mime-button-line-format "%{%([%p. %d%T]%)%}%e\n"
  "The following specs can be used:
%t  The MIME type
%T  MIME type, along with additional info
%n  The `name' parameter
%d  The description, if any
%l  The length of the encoded part
%p  The part identifier number
%e  Dots if the part isn't displayed")

(defvar gnus-mime-button-line-format-alist
  '((?t gnus-tmp-type ?s)
    (?T gnus-tmp-type-long ?s)
    (?n gnus-tmp-name ?s)
    (?d gnus-tmp-description ?s)
    (?p gnus-tmp-id ?s)
    (?l gnus-tmp-length ?d)
    (?e gnus-tmp-dots ?s)))

(defvar gnus-mime-button-commands
  '((gnus-article-press-button "\r" "Toggle Display")
    (gnus-mime-view-part "v" "View Interactively...")
    (gnus-mime-view-part-as-type "t" "View As Type...")
    (gnus-mime-save-part "o" "Save...")
    (gnus-mime-copy-part "c" "View As Text, In Other Buffer")
    (gnus-mime-inline-part "i" "View As Text, In This Buffer")
    (gnus-mime-internalize-part "E" "View Internally")
    (gnus-mime-externalize-part "e" "View Externally")
    (gnus-mime-pipe-part "|" "Pipe To Command...")))

(defun gnus-article-mime-part-status ()
  (if gnus-article-mime-handle-alist-1
      (format " (%d parts)" (length gnus-article-mime-handle-alist-1))
    ""))

(defvar gnus-mime-button-map nil)
(unless gnus-mime-button-map
  (setq gnus-mime-button-map (make-sparse-keymap))
  (set-keymap-parent gnus-mime-button-map gnus-article-mode-map)
  (define-key gnus-mime-button-map gnus-mouse-2 'gnus-article-push-button)
  (define-key gnus-mime-button-map gnus-down-mouse-3 'gnus-mime-button-menu)
  (mapcar (lambda (c)
            (define-key gnus-mime-button-map (cadr c) (car c)))
          gnus-mime-button-commands))

(defun gnus-mime-button-menu (event)
  "Construct a context-sensitive menu of MIME commands."
  (interactive "e")
  (save-excursion
    (let ((pos (event-start event)))
      (set-buffer (window-buffer (posn-window pos)))
      (goto-char (posn-point pos))
      (gnus-article-check-buffer)
      (let ((response (x-popup-menu
                       t `("MIME Part"
                           ("" ,@(mapcar (lambda (c)
                                           (cons (caddr c) (car c)))
                                         gnus-mime-button-commands))))))
        (if response
            (call-interactively response))))))

(defun gnus-mime-view-all-parts (&optional handles)
  "View all the MIME parts."
  (interactive)
  (save-current-buffer
    (set-buffer gnus-article-buffer)
    (let ((handles (or handles gnus-article-mime-handles))
          (mail-parse-charset gnus-newsgroup-charset)
          (mail-parse-ignored-charsets 
           (save-excursion (set-buffer gnus-summary-buffer)
                           gnus-newsgroup-ignored-charsets)))
      (if (stringp (car handles))
          (gnus-mime-view-all-parts (cdr handles))
        (mapcar 'mm-display-part handles)))))

(defun gnus-mime-save-part ()
  "Save the MIME part under point."
  (interactive)
  (gnus-article-check-buffer)
  (let ((data (get-text-property (point) 'gnus-data)))
    (mm-save-part data)))

(defun gnus-mime-pipe-part ()
  "Pipe the MIME part under point to a process."
  (interactive)
  (gnus-article-check-buffer)
  (let ((data (get-text-property (point) 'gnus-data)))
    (mm-pipe-part data)))

(defun gnus-mime-view-part ()
  "Interactively choose a viewing method for the MIME part under point."
  (interactive)
  (gnus-article-check-buffer)
  (let ((data (get-text-property (point) 'gnus-data)))
    (mm-interactively-view-part data)))

(defun gnus-mime-view-part-as-type-internal ()
  (gnus-article-check-buffer)
  (let* ((name (mail-content-type-get
                (mm-handle-type (get-text-property (point) 'gnus-data))
                'name))
         (def-type (and name (mm-default-file-encoding name))))
    (and def-type (cons def-type 0))))

(defun gnus-mime-view-part-as-type (mime-type)
  "Choose a MIME media type, and view the part as such."
  (interactive
   (list (completing-read
          "View as MIME type: "
          (mapcar (lambda (i) (list i i)) (mailcap-mime-types))
          nil nil
          (gnus-mime-view-part-as-type-internal))))
  (gnus-article-check-buffer)
  (let ((handle (get-text-property (point) 'gnus-data)))
    (gnus-mm-display-part
     (mm-make-handle (mm-handle-buffer handle)
                     (cons mime-type (cdr (mm-handle-type handle)))
                     (mm-handle-encoding handle)
                     (mm-handle-undisplayer handle)
                     (mm-handle-disposition handle)
                     (mm-handle-description handle)
                     (mm-handle-cache handle)
                     (mm-handle-id handle)))))

(defun gnus-mime-copy-part (&optional handle)
  "Put the the MIME part under point into a new buffer."
  (interactive)
  (gnus-article-check-buffer)
  (let* ((handle (or handle (get-text-property (point) 'gnus-data)))
         (contents (mm-get-part handle))|
         (base (file-name-nondirectory
                (or
                 (mail-content-type-get (mm-handle-type handle) 'name)
                 (mail-content-type-get (mm-handle-type handle)
                                        'filename)
                 "*decoded*")))
         (buffer (generate-new-buffer base)))
    (switch-to-buffer buffer)
    (insert contents)
    ;; We do it this way to make `normal-mode' set the appropriate mode.
    (unwind-protect
        (progn
          (setq buffer-file-name (expand-file-name base))
          (normal-mode))
      (setq buffer-file-name nil))
    (goto-char (point-min))))

(defun gnus-mime-inline-part (&optional handle)
  "Insert the MIME part under point into the current buffer."
  (interactive)
  (gnus-article-check-buffer)
  (let* ((handle (or handle (get-text-property (point) 'gnus-data)))
         contents
         (b (point))
         buffer-read-only)
    (if (mm-handle-undisplayer handle)
        (mm-remove-part handle)
      (setq contents (mm-get-part handle))
      (forward-line 2)
      (mm-insert-inline handle contents)
      (goto-char b))))

(defun gnus-mime-externalize-part (&optional handle)
  "View the MIME part under point with an external viewer."
  (interactive)
  (gnus-article-check-buffer)
  (let* ((handle (or handle (get-text-property (point) 'gnus-data)))
         (mm-user-display-methods nil)
         (mm-inline-large-images nil)
         (mail-parse-charset gnus-newsgroup-charset)
         (mail-parse-ignored-charsets 
          (save-excursion (set-buffer gnus-summary-buffer)
                          gnus-newsgroup-ignored-charsets)))
    (if (mm-handle-undisplayer handle)
        (mm-remove-part handle)
      (mm-display-part handle))))

(defun gnus-mime-internalize-part (&optional handle)
  "View the MIME part under point with an internal viewer.
In no internal viewer is available, use an external viewer."
  (interactive)
  (gnus-article-check-buffer)
  (let* ((handle (or handle (get-text-property (point) 'gnus-data)))
         (mm-inlined-types '(".*"))
         (mm-inline-large-images t)
         (mail-parse-charset gnus-newsgroup-charset)
         (mail-parse-ignored-charsets 
          (save-excursion (set-buffer gnus-summary-buffer)
                          gnus-newsgroup-ignored-charsets)))
    (if (mm-handle-undisplayer handle)
        (mm-remove-part handle)
      (mm-display-part handle))))

(defun gnus-article-part-wrapper (n function)
  (save-current-buffer
    (set-buffer gnus-article-buffer)
    (when (> n (length gnus-article-mime-handle-alist))
      (error "No such part"))
    (gnus-article-goto-part n)
    (let ((handle (cdr (assq n gnus-article-mime-handle-alist))))
      (funcall function handle))))

(defun gnus-article-pipe-part (n)
  "Pipe MIME part N, which is the numerical prefix."
  (interactive "p")
  (gnus-article-part-wrapper n 'mm-pipe-part))

(defun gnus-article-save-part (n)
  "Save MIME part N, which is the numerical prefix."
  (interactive "p")
  (gnus-article-part-wrapper n 'mm-save-part))

(defun gnus-article-interactively-view-part (n)
  "View MIME part N interactively, which is the numerical prefix."
  (interactive "p")
  (gnus-article-part-wrapper n 'mm-interactively-view-part))

(defun gnus-article-copy-part (n)
  "Copy MIME part N, which is the numerical prefix."
  (interactive "p")
  (gnus-article-part-wrapper n 'gnus-mime-copy-part))

(defun gnus-article-externalize-part (n)
  "View MIME part N externally, which is the numerical prefix."
  (interactive "p")
  (gnus-article-part-wrapper n 'gnus-mime-externalize-part))

(defun gnus-article-inline-part (n)
  "Inline MIME part N, which is the numerical prefix."
  (interactive "p")
  (gnus-article-part-wrapper n 'gnus-mime-inline-part))

(defun gnus-article-mime-match-handle-first (condition)
  (if condition
      (let ((alist gnus-article-mime-handle-alist) ihandle n)
        (while (setq ihandle (pop alist))
          (if (and (cond 
                    ((functionp condition)
                     (funcall condition (cdr ihandle)))
                    ((eq condition 'undisplayed) 
                     (not (or (mm-handle-undisplayer (cdr ihandle))
                              (equal (mm-handle-media-type (cdr ihandle))
                                     "multipart/alternative"))))
                    ((eq condition 'undisplayed-alternative)
                     (not (mm-handle-undisplayer (cdr ihandle))))
                    (t t))
                   (gnus-article-goto-part (car ihandle))
                   (or (not n) (< (car ihandle) n)))
              (setq n (car ihandle))))
        (or n 1))
    1))

(defun gnus-article-view-part (&optional n)
  "View MIME part N, which is the numerical prefix."
  (interactive "P")
  (save-current-buffer
    (set-buffer gnus-article-buffer)
    (or (numberp n) (setq n (gnus-article-mime-match-handle-first 
                             gnus-article-mime-match-handle-function)))
    (when (> n (length gnus-article-mime-handle-alist))
      (error "No such part"))
    (let ((handle (cdr (assq n gnus-article-mime-handle-alist))))
      (when (gnus-article-goto-part n)
        (if (equal (car handle) "multipart/alternative")
            (gnus-article-press-button)
          (when (eq (gnus-mm-display-part handle) 'internal)
            (gnus-set-window-start)))))))

(defun gnus-mm-display-part (handle)
  "Display HANDLE and fix MIME button."
  (let ((id (get-text-property (point) 'gnus-part))
        (point (point))
        buffer-read-only)
    (forward-line 1)
    (prog1
        (let ((window (selected-window))
              (mail-parse-charset gnus-newsgroup-charset)
              (mail-parse-ignored-charsets 
               (save-excursion (set-buffer gnus-summary-buffer)
                               gnus-newsgroup-ignored-charsets)))
          (save-excursion
            (unwind-protect
                (let ((win (get-buffer-window (current-buffer) t))
                      (beg (point)))
                  (when win
                    (select-window win))
                  (goto-char point)
                  (forward-line)
                  (if (mm-handle-displayed-p handle)
                      ;; This will remove the part.
                      (mm-display-part handle)
                    (save-restriction
                      (narrow-to-region (point) (1+ (point)))
                      (mm-display-part handle)
                      ;; We narrow to the part itself and
                      ;; then call the treatment functions.
                      (goto-char (point-min))
                      (forward-line 1)
                      (narrow-to-region (point) (point-max))
                      (gnus-treat-article
                       nil id
                       (1- (length gnus-article-mime-handles))
                       (mm-handle-media-type handle)))))
              (select-window window))))
      (goto-char point)
      (delete-region (gnus-point-at-bol) (progn (forward-line 1) (point)))
      (gnus-insert-mime-button
       handle id (list (mm-handle-displayed-p handle)))
      (goto-char point))))

(defun gnus-article-goto-part (n)
  "Go to MIME part N."
  (let ((point (text-property-any (point-min) (point-max) 'gnus-part n)))
    (when point
      (goto-char point))))

(defun gnus-insert-mime-button (handle gnus-tmp-id &optional displayed)
  (let ((gnus-tmp-name
         (or (mail-content-type-get (mm-handle-type handle)
                                    'name)
             (mail-content-type-get (mm-handle-disposition handle)
                                    'filename)
             ""))
        (gnus-tmp-type (mm-handle-media-type handle))
        (gnus-tmp-description
         (mail-decode-encoded-word-string (or (mm-handle-description handle)
                                              "")))
        (gnus-tmp-dots
         (if (if displayed (car displayed)
               (mm-handle-displayed-p handle))
             "" "..."))
        (gnus-tmp-length (with-current-buffer (mm-handle-buffer handle)
                           (buffer-size)))
        gnus-tmp-type-long b e)
    (when (string-match ".*/" gnus-tmp-name)
      (setq gnus-tmp-name (replace-match "" t t gnus-tmp-name)))
    (setq gnus-tmp-type-long (concat gnus-tmp-type
                                     (and (not (equal gnus-tmp-name ""))
                                          (concat "; " gnus-tmp-name))))
    (or (equal gnus-tmp-description "")
        (setq gnus-tmp-type-long (concat " --- " gnus-tmp-type-long)))
    (unless (bolp)
      (insert "\n"))
    (setq b (point))
    (gnus-eval-format
     gnus-mime-button-line-format gnus-mime-button-line-format-alist
     `(local-map ,gnus-mime-button-map
                 keymap ,gnus-mime-button-map
                 gnus-callback gnus-mm-display-part
                 gnus-part ,gnus-tmp-id
                 article-type annotation
                 gnus-data ,handle))
    (setq e (point))
    (widget-convert-button 'link b e
                           :mime-handle handle
                           :action 'gnus-widget-press-button
                           :button-keymap gnus-mime-button-map
                           :help-echo
                           (lambda (widget)
                             ;; Needed to properly clear the message
                             ;; due to a bug in wid-edit
                             (setq help-echo-owns-message t)
                             (format
                              "Click to %s the MIME part; %s for more options"
                              (if (mm-handle-displayed-p
                                   (widget-get widget :mime-handle))
                                  "hide" "show")
                              (if gnus-xemacs "button3" "mouse-3"))))))

(defun gnus-widget-press-button (elems el)
  (goto-char (widget-get elems :from))
  (gnus-article-press-button))

(defvar gnus-displaying-mime nil)

(defun gnus-display-mime (&optional ihandles)
  "Display the MIME parts."
  (save-excursion
    (save-selected-window
      (let ((window (get-buffer-window gnus-article-buffer))
            (point (point)))
        (when window
          (select-window window)
          ;; We have to do this since selecting the window
          ;; may change the point.  So we set the window point.
          (set-window-point window point)))
      (let* ((handles (or ihandles (mm-dissect-buffer) (mm-uu-dissect)))
             buffer-read-only handle name type b e display)
        (when (and (not ihandles)
                   (not gnus-displaying-mime))
          ;; Top-level call; we clean up.
          (when gnus-article-mime-handles
            (mm-destroy-parts gnus-article-mime-handles)
            (setq gnus-article-mime-handle-alist nil));; A trick.
          (setq gnus-article-mime-handles handles)
          ;; We allow users to glean info from the handles.
          (when gnus-article-mime-part-function
            (gnus-mime-part-function handles)))
        (if (and handles
                 (or (not (stringp (car handles)))
                     (cdr handles)))
            (progn
              (when (and (not ihandles)
                         (not gnus-displaying-mime))
                ;; Clean up for mime parts.
                (article-goto-body)
                (delete-region (point) (point-max)))
              (let ((gnus-displaying-mime t))
                (gnus-mime-display-part handles)))
          (save-restriction
            (article-goto-body)
            (narrow-to-region (point) (point-max))
            (gnus-treat-article nil 1 1)
            (widen)))
        (unless ihandles
          ;; Highlight the headers.
          (save-excursion
            (save-restriction
              (article-goto-body)
              (narrow-to-region (point-min) (point))
              (gnus-treat-article 'head))))))))

(defvar gnus-mime-display-multipart-as-mixed nil)

(defun gnus-mime-display-part (handle)
  (cond
   ;; Single part.
   ((not (stringp (car handle)))
    (gnus-mime-display-single handle))
   ;; User-defined multipart
   ((cdr (assoc (car handle) gnus-mime-multipart-functions))
    (funcall (cdr (assoc (car handle) gnus-mime-multipart-functions))
             handle))
   ;; multipart/alternative
   ((and (equal (car handle) "multipart/alternative")
         (not gnus-mime-display-multipart-as-mixed))
    (let ((id (1+ (length gnus-article-mime-handle-alist))))
      (push (cons id handle) gnus-article-mime-handle-alist)
      (gnus-mime-display-alternative (cdr handle) nil nil id)))
   ;; multipart/related
   ((and (equal (car handle) "multipart/related")
         (not gnus-mime-display-multipart-as-mixed))
    ;;;!!!We should find the start part, but we just default
    ;;;!!!to the first part.
    (gnus-mime-display-part (cadr handle)))
   ;; Other multiparts are handled like multipart/mixed.
   (t
    (gnus-mime-display-mixed (cdr handle)))))

(defun gnus-mime-part-function (handles)
  (if (stringp (car handles))
      (mapcar 'gnus-mime-part-function (cdr handles))
    (funcall gnus-article-mime-part-function handles)))

(defun gnus-mime-display-mixed (handles)
  (mapcar 'gnus-mime-display-part handles))

(defun gnus-mime-display-single (handle)
  (let ((type (mm-handle-media-type handle))
        (ignored gnus-ignored-mime-types)
        (not-attachment t)
        (move nil)
        display text)
    (catch 'ignored
      (progn
        (while ignored
          (when (string-match (pop ignored) type)
            (throw 'ignored nil)))
        (if (and (setq not-attachment
                       (and (not (mm-inline-override-p handle))
                            (or (not (mm-handle-disposition handle))
                                (equal (car (mm-handle-disposition handle))
                                       "inline")
                                (mm-attachment-override-p handle))))
                 (mm-automatic-display-p handle)
                 (or (mm-inlined-p handle)
                     (mm-automatic-external-display-p type)))
            (setq display t)
          (when (equal (mm-handle-media-supertype handle) "text")
            (setq text t)))
        (let ((id (1+ (length gnus-article-mime-handle-alist))))
          (push (cons id handle) gnus-article-mime-handle-alist)
          (when (or (not display)
                    (not (gnus-unbuttonized-mime-type-p type)))
            ;(gnus-article-insert-newline)
            (gnus-insert-mime-button
             handle id (list (or display (and not-attachment text))))
            (gnus-article-insert-newline)
            ;(gnus-article-insert-newline)
            (setq move t)))
        (let ((beg (point)))
          (cond
           (display
            (when move
              (forward-line -2)
              (setq beg (point)))
            (let ((mail-parse-charset gnus-newsgroup-charset)
                  (mail-parse-ignored-charsets 
                   (save-excursion (condition-case ()
                                       (set-buffer gnus-summary-buffer)
                                     (error))
                                   gnus-newsgroup-ignored-charsets)))
              (mm-display-part handle t))
            (goto-char (point-max)))
           ((and text not-attachment)
            (when move
              (forward-line -2)
              (setq beg (point)))
            (gnus-article-insert-newline)
            (mm-insert-inline handle (mm-get-part handle))
            (goto-char (point-max))))
          ;; Do highlighting.
          (save-excursion
            (save-restriction
              (narrow-to-region beg (point))
              (gnus-treat-article
               nil (length gnus-article-mime-handle-alist)
               (1- (length gnus-article-mime-handles))
               (mm-handle-media-type handle)))))))))

(defun gnus-unbuttonized-mime-type-p (type)
  "Say whether TYPE is to be unbuttonized."
  (unless gnus-inhibit-mime-unbuttonizing
    (catch 'found
      (let ((types gnus-unbuttonized-mime-types))
        (while types
          (when (string-match (pop types) type)
            (throw 'found t)))))))

(defun gnus-article-insert-newline ()
  "Insert a newline, but mark it as undeletable."
  (gnus-put-text-property
   (point) (progn (insert "\n") (point)) 'gnus-undeletable t))

(defun gnus-mime-display-alternative (handles &optional preferred ibegend id)
  (let* ((preferred (or preferred (mm-preferred-alternative handles)))
         (ihandles handles)
         (point (point))
         handle buffer-read-only from props begend not-pref)
    (save-window-excursion
      (save-restriction
        (when ibegend
          (narrow-to-region (car ibegend)
                            (or (cdr ibegend)
                                (progn
                                  (goto-char (car ibegend))
                                  (forward-line 2)
                                  (point))))
          (delete-region (point-min) (point-max))
          (mm-remove-parts handles))
        (setq begend (list (point-marker)))
        ;; Do the toggle.
        (unless (setq not-pref (cadr (member preferred ihandles)))
          (setq not-pref (car ihandles)))
        (when (or ibegend
                  (not (gnus-unbuttonized-mime-type-p
                        "multipart/alternative")))
          (gnus-add-text-properties
           (setq from (point))
           (progn
             (insert (format "%d.  " id))
             (point))
           `(gnus-callback
             (lambda (handles)
               (unless ,(not ibegend)
                 (setq gnus-article-mime-handle-alist
                       ',gnus-article-mime-handle-alist))
               (gnus-mime-display-alternative
                ',ihandles ',not-pref ',begend ,id))
             local-map ,gnus-mime-button-map
             ,gnus-mouse-face-prop ,gnus-article-mouse-face
             face ,gnus-article-button-face
             keymap ,gnus-mime-button-map
             gnus-part ,id
             gnus-data ,handle))
          (widget-convert-button 'link from (point)
                                 :action 'gnus-widget-press-button
                                 :button-keymap gnus-widget-button-keymap)
          ;; Do the handles
          (while (setq handle (pop handles))
            (gnus-add-text-properties
             (setq from (point))
             (progn
               (insert (format "(%c) %-18s"
                               (if (equal handle preferred) ?* ? )
                               (mm-handle-media-type handle)))
               (point))
             `(gnus-callback
               (lambda (handles)
                 (unless ,(not ibegend)
                   (setq gnus-article-mime-handle-alist
                         ',gnus-article-mime-handle-alist))
                 (gnus-mime-display-alternative
                  ',ihandles ',handle ',begend ,id))
               local-map ,gnus-mime-button-map
               ,gnus-mouse-face-prop ,gnus-article-mouse-face
               face ,gnus-article-button-face
               keymap ,gnus-mime-button-map
               gnus-part ,id
               gnus-data ,handle))
            (widget-convert-button 'link from (point)
                                   :action 'gnus-widget-press-button
                                   :button-keymap gnus-widget-button-keymap)
            (insert "  "))
          (insert "\n\n"))
        (when preferred
          (if (stringp (car preferred))
              (gnus-display-mime preferred)
            (let ((mail-parse-charset gnus-newsgroup-charset)
                  (mail-parse-ignored-charsets 
                   (save-excursion (set-buffer gnus-summary-buffer)
                                   gnus-newsgroup-ignored-charsets)))
              (mm-display-part preferred)
              ;; Do highlighting.
              (save-excursion
                (save-restriction
                  (narrow-to-region (car begend) (point-max))
                  (gnus-treat-article
                   nil (length gnus-article-mime-handle-alist)
                   (1- (length gnus-article-mime-handles))
                   (mm-handle-media-type handle))))))
          (goto-char (point-max))
          (setcdr begend (point-marker)))))
    (when ibegend
      (goto-char point))))

(defun gnus-article-wash-status ()
  "Return a string which display status of article washing."
  (save-excursion
    (set-buffer gnus-article-buffer)
    (let ((cite (memq 'cite gnus-article-wash-types))
          (headers (memq 'headers gnus-article-wash-types))
          (boring (memq 'boring-headers gnus-article-wash-types))
          (pgp (memq 'pgp gnus-article-wash-types))
          (pem (memq 'pem gnus-article-wash-types))
          (signature (memq 'signature gnus-article-wash-types))
          (overstrike (memq 'overstrike gnus-article-wash-types))
          (emphasis (memq 'emphasis gnus-article-wash-types)))
      (format "%c%c%c%c%c%c"
              (if cite ?c ? )
              (if (or headers boring) ?h ? )
              (if (or pgp pem) ?p ? )
              (if signature ?s ? )
              (if overstrike ?o ? )
              (if emphasis ?e ? )))))

(defalias 'gnus-article-hide-headers-if-wanted 'gnus-article-maybe-hide-headers)

(defun gnus-article-maybe-hide-headers ()
  "Hide unwanted headers if `gnus-have-all-headers' is nil.
Provided for backwards compatibility."
  (when (and (or (not (gnus-buffer-live-p gnus-summary-buffer))
                 (not (save-excursion (set-buffer gnus-summary-buffer)
                                      gnus-have-all-headers)))
             (not gnus-inhibit-hiding))
    (gnus-article-hide-headers)))

;;; Article savers.

(defun gnus-output-to-file (file-name)
  "Append the current article to a file named FILE-NAME."
  (let ((artbuf (current-buffer)))
    (with-temp-buffer
      (insert-buffer-substring artbuf)
      ;; Append newline at end of the buffer as separator, and then
      ;; save it to file.
      (goto-char (point-max))
      (insert "\n")
      (mm-append-to-file (point-min) (point-max) file-name)
      t)))

(defun gnus-narrow-to-page (&optional arg)
  "Narrow the article buffer to a page.
If given a numerical ARG, move forward ARG pages."
  (interactive "P")
  (setq arg (if arg (prefix-numeric-value arg) 0))
  (save-excursion
    (set-buffer gnus-article-buffer)
    (goto-char (point-min))
    (widen)
    ;; Remove any old next/prev buttons.
    (when (gnus-visual-p 'page-marker)
      (let ((buffer-read-only nil))
        (gnus-remove-text-with-property 'gnus-prev)
        (gnus-remove-text-with-property 'gnus-next)))
    (when
        (cond ((< arg 0)
               (re-search-backward page-delimiter nil 'move (1+ (abs arg))))
              ((> arg 0)
               (re-search-forward page-delimiter nil 'move arg)))
      (goto-char (match-end 0)))
    (narrow-to-region
     (point)
     (if (re-search-forward page-delimiter nil 'move)
         (match-beginning 0)
       (point)))
    (when (and (gnus-visual-p 'page-marker)
               (not (= (point-min) 1)))
      (save-excursion
        (goto-char (point-min))
        (gnus-insert-prev-page-button)))
    (when (and (gnus-visual-p 'page-marker)
               (< (+ (point-max) 2) (buffer-size)))
      (save-excursion
        (goto-char (point-max))
        (gnus-insert-next-page-button)))))

;; Article mode commands

(defun gnus-article-goto-next-page ()
  "Show the next page of the article."
  (interactive)
  (when (gnus-article-next-page)
    (goto-char (point-min))
    (gnus-article-read-summary-keys nil (gnus-character-to-event ?n))))

(defun gnus-article-goto-prev-page ()
  "Show the next page of the article."
  (interactive)
  (if (bobp) (gnus-article-read-summary-keys nil (gnus-character-to-event ?p))
    (gnus-article-prev-page nil)))

(defun gnus-article-next-page (&optional lines)
  "Show the next page of the current article.
If end of article, return non-nil.  Otherwise return nil.
Argument LINES specifies lines to be scrolled up."
  (interactive "p")
  (move-to-window-line -1)
  (if (save-excursion
        (end-of-line)
        ;; Redisplay before the visibility test; else we don't DTRT
        ;; with Emacs 21 images, for instance.
        (sit-for 0)
        (and (pos-visible-in-window-p)  ;Not continuation line.
             (eobp)))
      ;; Nothing in this page.
      (if (or (not gnus-page-broken)
              (save-excursion
                (save-restriction
                  (widen) (forward-line 1) (eobp)))) ;Real end-of-buffer?
          t                             ;Nothing more.
        (gnus-narrow-to-page 1)         ;Go to next page.
        nil)
    ;; More in this page.
    (let ((scroll-in-place nil))
      (condition-case ()
          (scroll-up lines)
        (end-of-buffer
         ;; Long lines may cause an end-of-buffer error.
         (goto-char (point-max)))))
    (move-to-window-line 0)
    nil))

(defun gnus-article-prev-page (&optional lines)
  "Show previous page of current article.
Argument LINES specifies lines to be scrolled down."
  (interactive "p")
  (move-to-window-line 0)
  (if (and gnus-page-broken
           (bobp)
           (not (save-restriction (widen) (bobp)))) ;Real beginning-of-buffer?
      (progn
        (gnus-narrow-to-page -1)        ;Go to previous page.
        (goto-char (point-max))
        (recenter -1))
    (let ((scroll-in-place nil))
      (prog1
          (condition-case ()
              (scroll-down lines)
            (beginning-of-buffer
             (goto-char (point-min))))
        (move-to-window-line 0)))))

(defun gnus-article-refer-article ()
  "Read article specified by message-id around point."
  (interactive)
  (let ((point (point)))
    (search-forward ">" nil t)          ;Move point to end of "<....>".
    (if (re-search-backward "\\(<[^<> \t\n]+>\\)" nil t)
        (let ((message-id (match-string 1)))
          (goto-char point)
          (set-buffer gnus-summary-buffer)
          (gnus-summary-refer-article message-id))
      (goto-char (point))
      (error "No references around point"))))

(defun gnus-article-show-summary ()
  "Reconfigure windows to show summary buffer."
  (interactive)
  (if (not (gnus-buffer-live-p gnus-summary-buffer))
      (error "There is no summary buffer for this article buffer")
    (gnus-article-set-globals)
    (gnus-configure-windows 'article)
    (gnus-summary-goto-subject gnus-current-article)
    (gnus-summary-position-point)))

(defun gnus-article-describe-briefly ()
  "Describe article mode commands briefly."
  (interactive)
  (gnus-message 6 (substitute-command-keys "\\<gnus-article-mode-map>\\[gnus-article-goto-next-page]:Next page   \\[gnus-article-goto-prev-page]:Prev page  \\[gnus-article-show-summary]:Show summary  \\[gnus-info-find-node]:Run Info  \\[gnus-article-describe-briefly]:This help")))

(defun gnus-article-summary-command ()
  "Execute the last keystroke in the summary buffer."
  (interactive)
  (let ((obuf (current-buffer))
        (owin (current-window-configuration))
        func)
    (switch-to-buffer gnus-article-current-summary 'norecord)
    (setq func (lookup-key (current-local-map) (this-command-keys)))
    (call-interactively func)
    (set-buffer obuf)
    (set-window-configuration owin)
    (set-window-point (get-buffer-window (current-buffer)) (point))))

(defun gnus-article-summary-command-nosave ()
  "Execute the last keystroke in the summary buffer."
  (interactive)
  (let (func)
    (pop-to-buffer gnus-article-current-summary 'norecord)
    (setq func (lookup-key (current-local-map) (this-command-keys)))
    (call-interactively func)))

(defun gnus-article-check-buffer ()
  "Beep if not in an article buffer."
  (unless (equal major-mode 'gnus-article-mode)
    (error "Command invoked outside of a Gnus article buffer")))

(defun gnus-article-read-summary-keys (&optional arg key not-restore-window)
  "Read a summary buffer key sequence and execute it from the article buffer."
  (interactive "P")
  (gnus-article-check-buffer)
  (let ((nosaves
         '("q" "Q"  "c" "r" "R" "\C-c\C-f" "m"  "a" "f" "F"
           "Zc" "ZC" "ZE" "ZQ" "ZZ" "Zn" "ZR" "ZG" "ZN" "ZP"
           "=" "^" "\M-^" "|"))
        (nosave-but-article
         '("A\r"))
        (nosave-in-article
         '("\C-d"))
        (up-to-top
         '("n" "Gn" "p" "Gp"))
        keys new-sum-point)
    (save-excursion
      (set-buffer gnus-article-current-summary)
      (let (gnus-pick-mode)
        (push (or key last-command-event) unread-command-events)
        (setq keys (if gnus-xemacs
                       (events-to-keys (read-key-sequence nil))
                     (read-key-sequence nil)))))
                     
    (message "")

    (if (or (member keys nosaves)
            (member keys nosave-but-article)
            (member keys nosave-in-article))
        (let (func)
          (save-window-excursion
            (pop-to-buffer gnus-article-current-summary 'norecord)
            ;; We disable the pick minor mode commands.
            (let (gnus-pick-mode)
              (setq func (lookup-key (current-local-map) keys))))
          (if (or (not func)
                  (numberp func))
              (ding)
            (unless (member keys nosave-in-article)
              (set-buffer gnus-article-current-summary))
            (call-interactively func)
            (setq new-sum-point (point)))
          (when (member keys nosave-but-article)
            (pop-to-buffer gnus-article-buffer 'norecord)))
      ;; These commands should restore window configuration.
      (let ((obuf (current-buffer))
            (owin (current-window-configuration))
            (opoint (point))
            (summary gnus-article-current-summary)
            func in-buffer selected)
        (if not-restore-window
            (pop-to-buffer summary 'norecord)
          (switch-to-buffer summary 'norecord))
        (setq in-buffer (current-buffer))
        ;; We disable the pick minor mode commands.
        (if (setq func (let (gnus-pick-mode)
                         (lookup-key (current-local-map) keys)))
            (progn
              (call-interactively func)
              (setq new-sum-point (point)))
          (ding))
        (when (eq in-buffer (current-buffer))
          (setq selected (gnus-summary-select-article))
          (set-buffer obuf)
          (unless not-restore-window
            (set-window-configuration owin))
          (when (eq selected 'old)
            (article-goto-body)
            (set-window-start (get-buffer-window (current-buffer))
                              1)
            (set-window-point (get-buffer-window (current-buffer))
                              (point)))
          (let ((win (get-buffer-window gnus-article-current-summary)))
            (when win
              (set-window-point win new-sum-point))))))))

(defun gnus-article-hide (&optional arg force)
  "Hide all the gruft in the current article.
This means that PGP stuff, signatures, cited text and (some)
headers will be hidden.
If given a prefix, show the hidden text instead."
  (interactive (append (gnus-article-hidden-arg) (list 'force)))
  (gnus-article-hide-headers arg)
  (gnus-article-hide-list-identifiers arg)
  (gnus-article-hide-pgp arg)
  (gnus-article-hide-citation-maybe arg force)
  (gnus-article-hide-signature arg))

(defun gnus-article-maybe-highlight ()
  "Do some article highlighting if article highlighting is requested."
  (when (gnus-visual-p 'article-highlight 'highlight)
    (gnus-article-highlight-some)))

(defun gnus-check-group-server ()
  ;; Make sure the connection to the server is alive.
  (unless (gnus-server-opened
           (gnus-find-method-for-group gnus-newsgroup-name))
    (gnus-check-server (gnus-find-method-for-group gnus-newsgroup-name))
    (gnus-request-group gnus-newsgroup-name t)))

(defun gnus-request-article-this-buffer (article group)
  "Get an article and insert it into this buffer."
  (let (do-update-line sparse-header)
    (prog1
        (save-excursion
          (erase-buffer)
          (gnus-kill-all-overlays)
          (setq group (or group gnus-newsgroup-name))

          ;; Using `gnus-request-article' directly will insert the article into
          ;; `nntp-server-buffer' - so we'll save some time by not having to
          ;; copy it from the server buffer into the article buffer.

          ;; We only request an article by message-id when we do not have the
          ;; headers for it, so we'll have to get those.
          (when (stringp article)
            (gnus-read-header article))

          ;; If the article number is negative, that means that this article
          ;; doesn't belong in this newsgroup (possibly), so we find its
          ;; message-id and request it by id instead of number.
          (when (and (numberp article)
                     gnus-summary-buffer
                     (get-buffer gnus-summary-buffer)
                     (gnus-buffer-exists-p gnus-summary-buffer))
            (save-excursion
              (set-buffer gnus-summary-buffer)
              (let ((header (gnus-summary-article-header article)))
                (when (< article 0)
                  (cond
                   ((memq article gnus-newsgroup-sparse)
                    ;; This is a sparse gap article.
                    (setq do-update-line article)
                    (setq article (mail-header-id header))
                    (setq sparse-header (gnus-read-header article))
                    (setq gnus-newsgroup-sparse
                          (delq article gnus-newsgroup-sparse)))
                   ((vectorp header)
                    ;; It's a real article.
                    (setq article (mail-header-id header)))
                   (t
                    ;; It is an extracted pseudo-article.
                    (setq article 'pseudo)
                    (gnus-request-pseudo-article header))))

                (let ((method (gnus-find-method-for-group
                               gnus-newsgroup-name)))
                  (when (and (eq (car method) 'nneething)
                             (vectorp header))
                    (let ((dir (concat
                                (file-name-as-directory
                                 (or (cadr (assq 'nneething-address method))
                                     (nth 1 method)))
                                (mail-header-subject header))))
                      (when (file-directory-p dir)
                        (setq article 'nneething)
                        (gnus-group-enter-directory dir))))))))

          (cond
           ;; Refuse to select canceled articles.
           ((and (numberp article)
                 gnus-summary-buffer
                 (get-buffer gnus-summary-buffer)
                 (gnus-buffer-exists-p gnus-summary-buffer)
                 (eq (cdr (save-excursion
                            (set-buffer gnus-summary-buffer)
                            (assq article gnus-newsgroup-reads)))
                     gnus-canceled-mark))
            nil)
           ;; We first check `gnus-original-article-buffer'.
           ((and (get-buffer gnus-original-article-buffer)
                 (numberp article)
                 (save-excursion
                   (set-buffer gnus-original-article-buffer)
                   (and (equal (car gnus-original-article) group)
                        (eq (cdr gnus-original-article) article))))
            (insert-buffer-substring gnus-original-article-buffer)
            'article)
           ;; Check the backlog.
           ((and gnus-keep-backlog
                 (gnus-backlog-request-article group article (current-buffer)))
            'article)
           ;; Check asynchronous pre-fetch.
           ((gnus-async-request-fetched-article group article (current-buffer))
            (gnus-async-prefetch-next group article gnus-summary-buffer)
            (when (and (numberp article) gnus-keep-backlog)
              (gnus-backlog-enter-article group article (current-buffer)))
            'article)
           ;; Check the cache.
           ((and gnus-use-cache
                 (numberp article)
                 (gnus-cache-request-article article group))
            'article)
           ;; Get the article and put into the article buffer.
           ((or (stringp article)
                (numberp article))
            (let ((gnus-override-method gnus-override-method)
                  (methods (and (stringp article) 
                                gnus-refer-article-method))
                  result
                  (buffer-read-only nil))
              (setq methods
                    (if (listp methods)
                        methods
                      (list methods)))
              (when (and (null gnus-override-method)
                         methods)
                (setq gnus-override-method (pop methods)))
              (while (not result)
                (when (eq gnus-override-method 'current)
                  (setq gnus-override-method gnus-current-select-method))
                (erase-buffer)
                (gnus-kill-all-overlays)
                (let ((gnus-newsgroup-name group))
                  (gnus-check-group-server))
                (when (gnus-request-article article group (current-buffer))
                  (when (numberp article)
                    (gnus-async-prefetch-next group article 
                                              gnus-summary-buffer)
                    (when gnus-keep-backlog
                      (gnus-backlog-enter-article
                       group article (current-buffer))))
                  (setq result 'article))
                (if (not result)
                    (if methods
                        (setq gnus-override-method (pop methods))
                      (setq result 'done))))
              (and (eq result 'article) 'article)))
           ;; It was a pseudo.
           (t article)))

      ;; Associate this article with the current summary buffer.
      (setq gnus-article-current-summary gnus-summary-buffer)

      ;; Take the article from the original article buffer
      ;; and place it in the buffer it's supposed to be in.
      (when (and (get-buffer gnus-article-buffer)
                 (equal (buffer-name (current-buffer))
                        (buffer-name (get-buffer gnus-article-buffer))))
        (save-excursion
          (if (get-buffer gnus-original-article-buffer)
              (set-buffer gnus-original-article-buffer)
            (set-buffer (gnus-get-buffer-create gnus-original-article-buffer))
            (buffer-disable-undo)
            (setq major-mode 'gnus-original-article-mode)
            (setq buffer-read-only t))
          (let (buffer-read-only)
            (erase-buffer)
            (insert-buffer-substring gnus-article-buffer))
          (setq gnus-original-article (cons group article)))

        ;; Decode charsets.
        (run-hooks 'gnus-article-decode-hook)
        ;; Mark article as decoded or not.
        (setq gnus-article-decoded-p gnus-article-decode-hook))

      ;; Update sparse articles.
      (when (and do-update-line
                 (or (numberp article)
                     (stringp article)))
        (let ((buf (current-buffer)))
          (set-buffer gnus-summary-buffer)
          (gnus-summary-update-article do-update-line sparse-header)
          (gnus-summary-goto-subject do-update-line nil t)
          (set-window-point (get-buffer-window (current-buffer) t)
                            (point))
          (set-buffer buf))))))

;;;
;;; Article editing
;;;

(defcustom gnus-article-edit-mode-hook nil
  "Hook run in article edit mode buffers."
  :group 'gnus-article-various
  :type 'hook)

(defvar gnus-article-edit-done-function nil)

(defvar gnus-article-edit-mode-map nil)

;; Should we be using derived.el for this?
(unless gnus-article-edit-mode-map
  (setq gnus-article-edit-mode-map (make-sparse-keymap))
  (set-keymap-parent gnus-article-edit-mode-map text-mode-map)

  (gnus-define-keys gnus-article-edit-mode-map
    "\C-c\C-c" gnus-article-edit-done
    "\C-c\C-k" gnus-article-edit-exit)

  (gnus-define-keys (gnus-article-edit-wash-map
                     "\C-c\C-w" gnus-article-edit-mode-map)
    "f" gnus-article-edit-full-stops))

(defun gnus-article-edit-mode ()
  "Major mode for editing articles.
This is an extended text-mode.

\\{gnus-article-edit-mode-map}"
  (interactive)
  (setq major-mode 'gnus-article-edit-mode)
  (setq mode-name "Article Edit")
  (use-local-map gnus-article-edit-mode-map)
  (make-local-variable 'gnus-article-edit-done-function)
  (make-local-variable 'gnus-prev-winconf)
  (setq buffer-read-only nil)
  (buffer-enable-undo)
  (widen)
  (gnus-run-hooks 'text-mode-hook 'gnus-article-edit-mode-hook))

(defun gnus-article-edit (&optional force)
  "Edit the current article.
This will have permanent effect only in mail groups.
If FORCE is non-nil, allow editing of articles even in read-only
groups."
  (interactive "P")
  (when (and (not force)
             (gnus-group-read-only-p))
    (error "The current newsgroup does not support article editing"))
  (gnus-article-date-original)
  (gnus-article-edit-article
   'ignore
   `(lambda (no-highlight)
      'ignore
      (gnus-summary-edit-article-done
       ,(or (mail-header-references gnus-current-headers) "")
       ,(gnus-group-read-only-p) ,gnus-summary-buffer no-highlight))))

(defun gnus-article-edit-article (start-func exit-func)
  "Start editing the contents of the current article buffer."
  (let ((winconf (current-window-configuration)))
    (set-buffer gnus-article-buffer)
    (gnus-article-edit-mode)
    (funcall start-func)
    (gnus-configure-windows 'edit-article)
    (setq gnus-article-edit-done-function exit-func)
    (setq gnus-prev-winconf winconf)
    (gnus-message 6 "C-c C-c to end edits")))

(defun gnus-article-edit-done (&optional arg)
  "Update the article edits and exit."
  (interactive "P")
  (save-excursion
    (save-restriction
      (widen)
      (when (article-goto-body)
        (let ((lines (count-lines (point) (point-max)))
              (length (- (point-max) (point)))
              (case-fold-search t)
              (body (copy-marker (point))))
          (goto-char (point-min))
          (when (re-search-forward "^content-length:[ \t]\\([0-9]+\\)" body t)
            (delete-region (match-beginning 1) (match-end 1))
            (insert (number-to-string length)))
          (goto-char (point-min))
          (when (re-search-forward
                 "^x-content-length:[ \t]\\([0-9]+\\)" body t)
            (delete-region (match-beginning 1) (match-end 1))
            (insert (number-to-string length)))
          (goto-char (point-min))
          (when (re-search-forward "^lines:[ \t]\\([0-9]+\\)" body t)
            (delete-region (match-beginning 1) (match-end 1))
            (insert (number-to-string lines)))))))
  (let ((func gnus-article-edit-done-function)
        (buf (current-buffer))
        (start (window-start)))
    (gnus-article-edit-exit)
    (save-excursion
      (set-buffer buf)
      (let ((buffer-read-only nil))
        (funcall func arg))
      ;; The cache and backlog have to be flushed somewhat.
      (when gnus-keep-backlog
        (gnus-backlog-remove-article
         (car gnus-article-current) (cdr gnus-article-current)))
      ;; Flush original article as well.
      (save-excursion
        (when (get-buffer gnus-original-article-buffer)
          (set-buffer gnus-original-article-buffer)
          (setq gnus-original-article nil)))
      (when gnus-use-cache
        (gnus-cache-update-article
         (car gnus-article-current) (cdr gnus-article-current))))
    (set-buffer buf)
    (set-window-start (get-buffer-window buf) start)
    (set-window-point (get-buffer-window buf) (point))))

(defun gnus-article-edit-exit ()
  "Exit the article editing without updating."
  (interactive)
  ;; We remove all text props from the article buffer.
  (let ((buf (format "%s" (buffer-string)))
        (curbuf (current-buffer))
        (p (point))
        (window-start (window-start)))
    (erase-buffer)
    (insert buf)
    (let ((winconf gnus-prev-winconf))
      (gnus-article-mode)
      (set-window-configuration winconf)
      ;; Tippy-toe some to make sure that point remains where it was.
      (save-current-buffer
        (set-buffer curbuf)
        (set-window-start (get-buffer-window (current-buffer)) window-start)
        (goto-char p)))))

(defun gnus-article-edit-full-stops ()
  "Interactively repair spacing at end of sentences."
  (interactive)
  (save-excursion
    (goto-char (point-min))
    (search-forward-regexp "^$" nil t)
    (let ((case-fold-search nil))
      (query-replace-regexp "\\([.!?][])}]* \\)\\([[({A-Z]\\)" "\\1 \\2"))))

;;;
;;; Article highlights
;;;

;; Written by Per Abrahamsen <abraham@iesd.auc.dk>.

;;; Internal Variables:

(defcustom gnus-button-url-regexp "\\b\\(\\(www\\.\\|\\(s?https?\\|ftp\\|file\\|gopher\\|news\\|telnet\\|wais\\|mailto\\):\\)\\(//[-a-zA-Z0-9_.]+:[0-9]*\\)?\\([-a-zA-Z0-9_=!?#$@~`%&*+|\\/:;.,]\\|\\w\\)+\\([-a-zA-Z0-9_=#$@~`%&*+|\\/]\\|\\w\\)\\)"
  "Regular expression that matches URLs."
  :group 'gnus-article-buttons
  :type 'regexp)

(defcustom gnus-button-alist
  `(("<\\(url:[>\n\t ]*?\\)?news:[>\n\t ]*\\([^>\n\t ]*@[^>\n\t ]*\\)>"
     0 t gnus-button-message-id 2)
    ("\\bnews:\\([^>\n\t ]*@[^>)!;:,\n\t ]*\\)" 0 t gnus-button-message-id 1)
    ("\\(\\b<\\(url:[>\n\t ]*\\)?news:[>\n\t ]*\\(//\\)?\\([^>\n\t ]*\\)>\\)"
     1 t
     gnus-button-fetch-group 4)
    ("\\bnews:\\(//\\)?\\([^'\">\n\t ]+\\)" 0 t gnus-button-fetch-group 2)
    ("\\bin\\( +article\\| +message\\)? +\\(<\\([^\n @<>]+@[^\n @<>]+\\)>\\)" 2
     t gnus-button-message-id 3)
    ("\\(<URL: *\\)mailto: *\\([^> \n\t]+\\)>" 0 t gnus-url-mailto 2)
    ("mailto:\\([-a-zA-Z.@_+0-9%]+\\)" 0 t gnus-url-mailto 1)
    ("\\bmailto:\\([^ \n\t]+\\)" 0 t gnus-url-mailto 1)
    ;; This is how URLs _should_ be embedded in text...
    ("<URL: *\\([^<>]*\\)>" 0 t gnus-button-embedded-url 1)
    ;; Raw URLs.
    (,gnus-button-url-regexp 0 t browse-url 0))
  "*Alist of regexps matching buttons in article bodies.

Each entry has the form (REGEXP BUTTON FORM CALLBACK PAR...), where
REGEXP: is the string matching text around the button,
BUTTON: is the number of the regexp grouping actually matching the button,
FORM: is a lisp expression which must eval to true for the button to
be added,
CALLBACK: is the function to call when the user push this button, and each
PAR: is a number of a regexp grouping whose text will be passed to CALLBACK.

CALLBACK can also be a variable, in that case the value of that
variable it the real callback function."
  :group 'gnus-article-buttons
  :type '(repeat (list regexp
                       (integer :tag "Button")
                       (sexp :tag "Form")
                       (function :tag "Callback")
                       (repeat :tag "Par"
                               :inline t
                               (integer :tag "Regexp group")))))

(defcustom gnus-header-button-alist
  `(("^\\(References\\|Message-I[Dd]\\):" "<[^>]+>"
     0 t gnus-button-message-id 0)
    ("^\\(From\\|Reply-To\\):" ": *\\(.+\\)$" 1 t gnus-button-reply 1)
    ("^\\(Cc\\|To\\):" "[^ \t\n<>,()\"]+@[^ \t\n<>,()\"]+"
     0 t gnus-button-mailto 0)
    ("^X-[Uu][Rr][Ll]:" ,gnus-button-url-regexp 0 t browse-url 0)
    ("^Subject:" ,gnus-button-url-regexp 0 t browse-url 0)
    ("^[^:]+:" ,gnus-button-url-regexp 0 t browse-url 0)
    ("^[^:]+:" "\\(<\\(url: \\)?news:\\([^>\n ]*\\)>\\)" 1 t
     gnus-button-message-id 3))
  "*Alist of headers and regexps to match buttons in article heads.

This alist is very similar to `gnus-button-alist', except that each
alist has an additional HEADER element first in each entry:

\(HEADER REGEXP BUTTON FORM CALLBACK PAR)

HEADER is a regexp to match a header.  For a fuller explanation, see
`gnus-button-alist'."
  :group 'gnus-article-buttons
  :group 'gnus-article-headers
  :type '(repeat (list (regexp :tag "Header")
                       regexp
                       (integer :tag "Button")
                       (sexp :tag "Form")
                       (function :tag "Callback")
                       (repeat :tag "Par"
                               :inline t
                               (integer :tag "Regexp group")))))

(defvar gnus-button-regexp nil)
(defvar gnus-button-marker-list nil)
;; Regexp matching any of the regexps from `gnus-button-alist'.

(defvar gnus-button-last nil)
;; The value of `gnus-button-alist' when `gnus-button-regexp' was build.

;;; Commands:

(defun gnus-article-push-button (event)
  "Check text under the mouse pointer for a callback function.
If the text under the mouse pointer has a `gnus-callback' property,
call it with the value of the `gnus-data' text property."
  (interactive "e")
  (set-buffer (window-buffer (posn-window (event-start event))))
  (let* ((pos (posn-point (event-start event)))
         (data (get-text-property pos 'gnus-data))
         (fun (get-text-property pos 'gnus-callback)))
    (goto-char pos)
    (when fun
      (funcall fun data))))

(defun gnus-article-press-button ()
  "Check text at point for a callback function.
If the text at point has a `gnus-callback' property,
call it with the value of the `gnus-data' text property."
  (interactive)
  (let* ((data (get-text-property (point) 'gnus-data))
         (fun (get-text-property (point) 'gnus-callback)))
    (when fun
      (funcall fun data))))

(defun gnus-article-highlight (&optional force)
  "Highlight current article.
This function calls `gnus-article-highlight-headers',
`gnus-article-highlight-citation',
`gnus-article-highlight-signature', and `gnus-article-add-buttons' to
do the highlighting.  See the documentation for those functions."
  (interactive (list 'force))
  (gnus-article-highlight-headers)
  (gnus-article-highlight-citation force)
  (gnus-article-highlight-signature)
  (gnus-article-add-buttons force)
  (gnus-article-add-buttons-to-head))

(defun gnus-article-highlight-some (&optional force)
  "Highlight current article.
This function calls `gnus-article-highlight-headers',
`gnus-article-highlight-signature', and `gnus-article-add-buttons' to
do the highlighting.  See the documentation for those functions."
  (interactive (list 'force))
  (gnus-article-highlight-headers)
  (gnus-article-highlight-signature)
  (gnus-article-add-buttons))

(defun gnus-article-highlight-headers ()
  "Highlight article headers as specified by `gnus-header-face-alist'."
  (interactive)
  (save-excursion
    (set-buffer gnus-article-buffer)
    (save-restriction
      (let ((alist gnus-header-face-alist)
            (buffer-read-only nil)
            (case-fold-search t)
            (inhibit-point-motion-hooks t)
            entry regexp header-face field-face from hpoints fpoints)
        (article-narrow-to-head)
        (while (setq entry (pop alist))
          (goto-char (point-min))
          (setq regexp (concat "^\\("
                               (if (string-equal "" (nth 0 entry))
                                   "[^\t ]"
                                 (nth 0 entry))
                               "\\)")
                header-face (nth 1 entry)
                field-face (nth 2 entry))
          (while (and (re-search-forward regexp nil t)
                      (not (eobp)))
            (beginning-of-line)
            (setq from (point))
            (unless (search-forward ":" nil t)
              (forward-char 1))
            (when (and header-face
                       (not (memq (point) hpoints)))
              (push (point) hpoints)
              (gnus-put-text-property from (point) 'face header-face))
            (when (and field-face
                       (not (memq (setq from (point)) fpoints)))
              (push from fpoints)
              (if (re-search-forward "^[^ \t]" nil t)
                  (forward-char -2)
                (goto-char (point-max)))
              (gnus-put-text-property from (point) 'face field-face))))))))

(defun gnus-article-highlight-signature ()
  "Highlight the signature in an article.
It does this by highlighting everything after
`gnus-signature-separator' using `gnus-signature-face'."
  (interactive)
  (save-excursion
    (set-buffer gnus-article-buffer)
    (let ((buffer-read-only nil)
          (inhibit-point-motion-hooks t))
      (save-restriction
        (when (and gnus-signature-face
                   (gnus-article-narrow-to-signature))
          (gnus-overlay-put (gnus-make-overlay (point-min) (point-max))
                            'face gnus-signature-face)
          (widen)
          (gnus-article-search-signature)
          (let ((start (match-beginning 0))
                (end (set-marker (make-marker) (1+ (match-end 0)))))
            (gnus-article-add-button start (1- end) 'gnus-signature-toggle
                                     end)))))))

(defun gnus-button-in-region-p (b e prop)
  "Say whether PROP exists in the region."
  (text-property-not-all b e prop nil))

(defun gnus-article-add-buttons (&optional force)
  "Find external references in the article and make buttons of them.
\"External references\" are things like Message-IDs and URLs, as
specified by `gnus-button-alist'."
  (interactive (list 'force))
  (save-excursion
    (set-buffer gnus-article-buffer)
    (let ((buffer-read-only nil)
          (inhibit-point-motion-hooks t)
          (case-fold-search t)
          (alist gnus-button-alist)
          beg entry regexp)
      ;; Remove all old markers.
      (let (marker entry new-list)
        (while (setq marker (pop gnus-button-marker-list))
          (if (or (< marker (point-min)) (>= marker (point-max)))
              (push marker new-list)
            (goto-char marker)
            (when (setq entry (gnus-button-entry))
              (put-text-property (match-beginning (nth 1 entry))
                                 (match-end (nth 1 entry))
                                 'gnus-callback nil))
            (set-marker marker nil)))
        (setq gnus-button-marker-list new-list))
      ;; We skip the headers.
      (article-goto-body)
      (setq beg (point))
      (while (setq entry (pop alist))
        (setq regexp (car entry))
        (goto-char beg)
        (while (re-search-forward regexp nil t)
          (let* ((start (and entry (match-beginning (nth 1 entry))))
                 (end (and entry (match-end (nth 1 entry))))
                 (from (match-beginning 0)))
            (when (and (or (eq t (nth 2 entry))
                           (eval (nth 2 entry)))
                       (not (gnus-button-in-region-p
                             start end 'gnus-callback)))
              ;; That optional form returned non-nil, so we add the
              ;; button.
              (gnus-article-add-button
               start end 'gnus-button-push
               (car (push (set-marker (make-marker) from)
                          gnus-button-marker-list))))))))))

;; Add buttons to the head of an article.
(defun gnus-article-add-buttons-to-head ()
  "Add buttons to the head of the article."
  (interactive)
  (save-excursion
    (set-buffer gnus-article-buffer)
    (save-restriction
      (let ((buffer-read-only nil)
            (inhibit-point-motion-hooks t)
            (case-fold-search t)
            (alist gnus-header-button-alist)
            entry beg end)
        (article-narrow-to-head)
        (while alist
          ;; Each alist entry.
          (setq entry (car alist)
                alist (cdr alist))
          (goto-char (point-min))
          (while (re-search-forward (car entry) nil t)
            ;; Each header matching the entry.
            (setq beg (match-beginning 0))
            (setq end (or (and (re-search-forward "^[^ \t]" nil t)
                               (match-beginning 0))
                          (point-max)))
            (goto-char beg)
            (while (re-search-forward (nth 1 entry) end t)
              ;; Each match within a header.
              (let* ((entry (cdr entry))
                     (start (match-beginning (nth 1 entry)))
                     (end (match-end (nth 1 entry)))
                     (form (nth 2 entry)))
                (goto-char (match-end 0))
                (when (eval form)
                  (gnus-article-add-button
                   start end (nth 3 entry)
                   (buffer-substring (match-beginning (nth 4 entry))
                                     (match-end (nth 4 entry)))))))
            (goto-char end)))))))

;;; External functions:

(defun gnus-article-add-button (from to fun &optional data)
  "Create a button between FROM and TO with callback FUN and data DATA."
  (when gnus-article-button-face
    (gnus-overlay-put (gnus-make-overlay from to)
                      'face gnus-article-button-face))
  (gnus-add-text-properties
   from to
   (nconc (and gnus-article-mouse-face
               (list gnus-mouse-face-prop gnus-article-mouse-face))
          (list 'gnus-callback fun)
          (and data (list 'gnus-data data))))
  (widget-convert-button 'link from to :action 'gnus-widget-press-button
                         :button-keymap gnus-widget-button-keymap))

;;; Internal functions:

(defun gnus-article-set-globals ()
  (save-excursion
    (set-buffer gnus-summary-buffer)
    (gnus-set-global-variables)))

(defun gnus-signature-toggle (end)
  (save-excursion
    (set-buffer gnus-article-buffer)
    (let ((buffer-read-only nil)
          (inhibit-point-motion-hooks t))
      (if (get-text-property end 'invisible)
          (gnus-article-unhide-text end (point-max))
        (gnus-article-hide-text end (point-max) gnus-hidden-properties)))))

(defun gnus-button-entry ()
  ;; Return the first entry in `gnus-button-alist' matching this place.
  (let ((alist gnus-button-alist)
        (entry nil))
    (while alist
      (setq entry (pop alist))
      (if (looking-at (car entry))
          (setq alist nil)
        (setq entry nil)))
    entry))

(defun gnus-button-push (marker)
  ;; Push button starting at MARKER.
  (save-excursion
    (goto-char marker)
    (let* ((entry (gnus-button-entry))
           (inhibit-point-motion-hooks t)
           (fun (nth 3 entry))
           (args (mapcar (lambda (group)
                           (let ((string (match-string group)))
                             (gnus-set-text-properties
                              0 (length string) nil string)
                             string))
                         (nthcdr 4 entry))))
      (cond
       ((fboundp fun)
        (apply fun args))
       ((and (boundp fun)
             (fboundp (symbol-value fun)))
        (apply (symbol-value fun) args))
       (t
        (gnus-message 1 "You must define `%S' to use this button"
                      (cons fun args)))))))

(defun gnus-button-message-id (message-id)
  "Fetch MESSAGE-ID."
  (save-excursion
    (set-buffer gnus-summary-buffer)
    (gnus-summary-refer-article message-id)))

(defun gnus-button-fetch-group (address)
  "Fetch GROUP specified by ADDRESS."
  (if (not (string-match "[:/]" address))
      ;; This is just a simple group url.
      (gnus-group-read-ephemeral-group address gnus-select-method)
    (if (not (string-match "^\\([^:/]+\\)\\(:\\([^/]+\\)/\\)?\\(.*\\)$"
                           address))
        (error "Can't parse %s" address)
      (gnus-group-read-ephemeral-group
       (match-string 4 address)
       `(nntp ,(match-string 1 address)
              (nntp-address ,(match-string 1 address))
              (nntp-port-number ,(if (match-end 3)
                                     (match-string 3 address)
                                   "nntp")))))))

(defun gnus-url-parse-query-string (query &optional downcase)
  (let (retval pairs cur key val)
    (setq pairs (split-string query "&"))
    (while pairs
      (setq cur (car pairs)
            pairs (cdr pairs))
      (if (not (string-match "=" cur))
          nil                           ; Grace
        (setq key (gnus-url-unhex-string (substring cur 0 (match-beginning 0)))
              val (gnus-url-unhex-string (substring cur (match-end 0) nil)))
        (if downcase
            (setq key (downcase key)))
        (setq cur (assoc key retval))
        (if cur
            (setcdr cur (cons val (cdr cur)))
          (setq retval (cons (list key val) retval)))))
    retval))

(defun gnus-url-unhex (x)
  (if (> x ?9)
      (if (>= x ?a)
          (+ 10 (- x ?a))
        (+ 10 (- x ?A)))
    (- x ?0)))

(defun gnus-url-unhex-string (str &optional allow-newlines)
  "Remove %XXX embedded spaces, etc in a url.
If optional second argument ALLOW-NEWLINES is non-nil, then allow the
decoding of carriage returns and line feeds in the string, which is normally
forbidden in URL encoding."
  (setq str (or str ""))
  (let ((tmp "")
        (case-fold-search t))
    (while (string-match "%[0-9a-f][0-9a-f]" str)
      (let* ((start (match-beginning 0))
             (ch1 (gnus-url-unhex (elt str (+ start 1))))
             (code (+ (* 16 ch1)
                      (gnus-url-unhex (elt str (+ start 2))))))
        (setq tmp (concat
                   tmp (substring str 0 start)
                   (cond
                    (allow-newlines
                     (char-to-string code))
                    ((or (= code ?\n) (= code ?\r))
                     " ")
                    (t (char-to-string code))))
              str (substring str (match-end 0)))))
    (setq tmp (concat tmp str))
    tmp))

(defun gnus-url-mailto (url)
  ;; Send mail to someone
  (when (string-match "mailto:/*\\(.*\\)" url)
    (setq url (substring url (match-beginning 1) nil)))
  (let (to args subject func)
    (if (string-match (regexp-quote "?") url)
        (setq to (gnus-url-unhex-string (substring url 0 (match-beginning 0)))
              args (gnus-url-parse-query-string
                    (substring url (match-end 0) nil) t))
      (setq to (gnus-url-unhex-string url)))
    (setq args (cons (list "to" to) args)
          subject (cdr-safe (assoc "subject" args)))
    (message-mail)
    (while args
      (setq func (intern-soft (concat "message-goto-" (downcase (caar args)))))
      (if (fboundp func)
          (funcall func)
        (message-position-on-field (caar args)))
      (insert (mapconcat 'identity (cdar args) ", "))
      (setq args (cdr args)))
    (if subject
        (message-goto-body)
      (message-goto-subject))))

(defun gnus-button-mailto (address)
  ;; Mail to ADDRESS.
  (set-buffer (gnus-copy-article-buffer))
  (message-reply address))

(defun gnus-button-reply (address)
  ;; Reply to ADDRESS.
  (message-reply address))

(defun gnus-button-embedded-url (address)
  "Browse ADDRESS."
  (browse-url (gnus-strip-whitespace address)))

;;; Next/prev buttons in the article buffer.

(defvar gnus-next-page-line-format "%{%(Next page...%)%}\n")
(defvar gnus-prev-page-line-format "%{%(Previous page...%)%}\n")

(defvar gnus-prev-page-map nil)
(unless gnus-prev-page-map
  (setq gnus-prev-page-map (make-sparse-keymap))
  (define-key gnus-prev-page-map gnus-mouse-2 'gnus-button-prev-page)
  (define-key gnus-prev-page-map "\r" 'gnus-button-prev-page))

(defun gnus-insert-prev-page-button ()
  (let ((buffer-read-only nil))
    (gnus-eval-format
     gnus-prev-page-line-format nil
     `(gnus-prev t local-map ,gnus-prev-page-map
                 gnus-callback gnus-article-button-prev-page
                 article-type annotation))))

(defvar gnus-next-page-map nil)
(unless gnus-next-page-map
  (setq gnus-next-page-map (make-keymap))
  (suppress-keymap gnus-prev-page-map)
  (define-key gnus-next-page-map gnus-mouse-2 'gnus-button-next-page)
  (define-key gnus-next-page-map "\r" 'gnus-button-next-page))

(defun gnus-button-next-page ()
  "Go to the next page."
  (interactive)
  (let ((win (selected-window)))
    (select-window (get-buffer-window gnus-article-buffer t))
    (gnus-article-next-page)
    (select-window win)))

(defun gnus-button-prev-page ()
  "Go to the prev page."
  (interactive)
  (let ((win (selected-window)))
    (select-window (get-buffer-window gnus-article-buffer t))
    (gnus-article-prev-page)
    (select-window win)))

(defun gnus-insert-next-page-button ()
  (let ((buffer-read-only nil))
    (gnus-eval-format gnus-next-page-line-format nil
                      `(gnus-next
                        t local-map ,gnus-next-page-map
                        gnus-callback gnus-article-button-next-page
                        article-type annotation))))

(defun gnus-article-button-next-page (arg)
  "Go to the next page."
  (interactive "P")
  (let ((win (selected-window)))
    (select-window (get-buffer-window gnus-article-buffer t))
    (gnus-article-next-page)
    (select-window win)))

(defun gnus-article-button-prev-page (arg)
  "Go to the prev page."
  (interactive "P")
  (let ((win (selected-window)))
    (select-window (get-buffer-window gnus-article-buffer t))
    (gnus-article-prev-page)
    (select-window win)))

(defvar gnus-decode-header-methods
  '(mail-decode-encoded-word-region)
  "List of methods used to decode headers.

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 only apply to thes newsgroups
whose names match REGEXP.

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

(defvar gnus-decode-header-methods-cache nil)

(defun gnus-multi-decode-header (start end)
  "Apply the functions from `gnus-encoded-word-methods' that match."
  (unless (and gnus-decode-header-methods-cache
               (eq gnus-newsgroup-name
                   (car gnus-decode-header-methods-cache)))
    (setq gnus-decode-header-methods-cache (list gnus-newsgroup-name))
    (mapcar (lambda (x)
              (if (symbolp x)
                  (nconc gnus-decode-header-methods-cache (list x))
                (if (and gnus-newsgroup-name
                         (string-match (car x) gnus-newsgroup-name))
                    (nconc gnus-decode-header-methods-cache
                           (list (cdr x))))))
          gnus-decode-header-methods))
  (let ((xlist gnus-decode-header-methods-cache))
    (pop xlist)
    (save-restriction
      (narrow-to-region start end)
      (while xlist
        (funcall (pop xlist) (point-min) (point-max))))))

;;;
;;; Treatment top-level handling.
;;;

(defun gnus-treat-article (condition &optional part-number total-parts type)
  (let ((length (- (point-max) (point-min)))
        (alist gnus-treatment-function-alist)
        (article-goto-body-goes-to-point-min-p t)
        (treated-type
         (or (not type)
             (catch 'found
               (let ((list gnus-article-treat-types))
                 (while list
                   (when (string-match (pop list) type)
                     (throw 'found t)))))))
        (highlightp (gnus-visual-p 'article-highlight 'highlight))
        val elem)
    (gnus-run-hooks 'gnus-part-display-hook)
    (while (setq elem (pop alist))
      (setq val
            (save-excursion
              (if (gnus-buffer-live-p gnus-summary-buffer)
                  (set-buffer gnus-summary-buffer))
              (symbol-value (car elem))))
      (when (and (or (consp val)
                     treated-type)
                 (gnus-treat-predicate val)
                 (or (not (get (car elem) 'highlight))
                     highlightp))
        (save-restriction
          (funcall (cadr elem)))))))

;; Dynamic variables.
(defvar part-number)
(defvar total-parts)
(defvar type)
(defvar condition)
(defvar length)
(defun gnus-treat-predicate (val)
  (cond
   ((null val)
    nil)
   ((and (listp val)
         (stringp (car val)))
    (apply 'gnus-or (mapcar `(lambda (s)
                               (string-match s ,(or gnus-newsgroup-name "")))
                            val)))
   ((listp val)
    (let ((pred (pop val)))
      (cond
       ((eq pred 'or)
        (apply 'gnus-or (mapcar 'gnus-treat-predicate val)))
       ((eq pred 'and)
        (apply 'gnus-and (mapcar 'gnus-treat-predicate val)))
       ((eq pred 'not)
        (not (gnus-treat-predicate (car val))))
       ((eq pred 'typep)
        (equal (car val) type))
       (t
        (error "%S is not a valid predicate" pred)))))
   (condition
    (eq condition val))
   ((eq val t)
    t)
   ((eq val 'head)
    nil)
   ((eq val 'last)
    (eq part-number total-parts))
   ((numberp val)
    (< length val))
   (t
    (error "%S is not a valid value" val))))

(gnus-ems-redefine)

(provide 'gnus-art)

(run-hooks 'gnus-art-load-hook)

;;; gnus-art.el ends here