lisp/gnus/gnus-cite.el

   1 ;;; gnus-cite.el --- parse citations in articles for Gnus
   2
   3 ;; Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
   4 ;;   2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
   5
   6 ;; Author: Per Abhiddenware
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;;; Code:
  26
  27 (eval-when-compile (require 'cl))
  28 (eval-when-compile
  29   (when (featurep 'xemacs)
  30     (require 'easy-mmode))) ; for `define-minor-mode'
  31
  32 (require 'gnus)
  33 (require 'gnus-range)
  34 (require 'gnus-art)
  35 (require 'message)      ; for message-cite-prefix-regexp
  36
  37 ;;; Customization:
  38
  39 (defgroup gnus-cite nil
  40   "Citation."
  41   :prefix "gnus-cite-"
  42   :link '(custom-manual "(gnus)Article Highlighting")
  43   :group 'gnus-article)
  44
  45 (defcustom gnus-cited-opened-text-button-line-format "%(%{[-]%}%)\n"
  46   "Format of opened cited text buttons."
  47   :group 'gnus-cite
  48   :type 'string)
  49
  50 (defcustom gnus-cited-closed-text-button-line-format "%(%{[+]%}%)\n"
  51   "Format of closed cited text buttons."
  52   :group 'gnus-cite
  53   :type 'string)
  54
  55 (defcustom gnus-cited-lines-visible nil
  56   "The number of lines of hidden cited text to remain visible.
  57 Or a pair (cons) of numbers which are the number of lines at the top
  58 and bottom of the text, respectively, to remain visible."
  59   :group 'gnus-cite
  60   :type '(choice (const :tag "none" nil)
  61                  integer
  62                  (cons :tag "Top and Bottom" integer integer)))
  63
  64 (defcustom gnus-cite-parse-max-size 25000
  65   "Maximum article size (in bytes) where parsing citations is allowed.
  66 Set it to nil to parse all articles."
  67   :group 'gnus-cite
  68   :type '(choice (const :tag "all" nil)
  69                  integer))
  70
  71 (defcustom gnus-cite-max-prefix 20
  72   "Maximum possible length for a citation prefix."
  73   :group 'gnus-cite
  74   :type 'integer)
  75
  76 (defcustom gnus-supercite-regexp
  77   (concat "^\\(" message-cite-prefix-regexp "\\)? *"
  78           ">>>>> +\"\\([^\"\n]+\\)\" +==")
  79   "*Regexp matching normal Supercite attribution lines.
  80 The first grouping must match prefixes added by other packages."
  81   :group 'gnus-cite
  82   :type 'regexp)
  83
  84 (defcustom gnus-supercite-secondary-regexp "^.*\"\\([^\"\n]+\\)\" +=="
  85   "Regexp matching mangled Supercite attribution lines.
  86 The first regexp group should match the Supercite attribution."
  87   :group 'gnus-cite
  88   :type 'regexp)
  89
  90 (defcustom gnus-cite-minimum-match-count 2
  91   "Minimum number of identical prefixes before we believe it's a citation."
  92   :group 'gnus-cite
  93   :type 'integer)
  94
  95 ;; Some Microsoft products put in a citation that extends to the
  96 ;; remainder of the message:
  97 ;;
  98 ;;     -----Original Message-----
  99 ;;     From: ...
 100 ;;     To: ...
 101 ;;     Sent: ...   [date, in non-RFC-2822 format]
 102 ;;     Subject: ...
 103 ;;
 104 ;;     Cited message, with no prefixes
 105 ;;
 106 ;; The four headers are always the same.  But note they are prone to
 107 ;; folding without additional indentation.
 108 ;;
 109 ;; Others use "----- Original Message -----" instead, and properly quote
 110 ;; the body using "> ".  This style is handled without special cases.
 111
 112 (defcustom gnus-cite-attribution-prefix
 113   "In article\\|in <\\|On \\(Mon\\|Tue\\|Wed\\|Thu\\|Fri\\|Sat\\|Sun\\),\\|----- ?Original Message ?-----"
 114   "*Regexp matching the beginning of an attribution line."
 115   :group 'gnus-cite
 116   :type 'regexp)
 117
 118 (defcustom gnus-cite-attribution-suffix
 119   "\\(\\(wrote\\|writes\\|said\\|says\\|>\\)\\(:\\|\\.\\.\\.\\)\\|----- ?Original Message ?-----\\)[ \t]*$"
 120   "*Regexp matching the end of an attribution line.
 121 The text matching the first grouping will be used as a button."
 122   :group 'gnus-cite
 123   :type 'regexp)
 124
 125 (defcustom gnus-cite-unsightly-citation-regexp
 126   "^-----Original Message-----\nFrom: \\(.+\n\\)+\n"
 127   "Regexp matching Microsoft-type rest-of-message citations."
 128   :version "22.1"
 129   :group 'gnus-cite
 130   :type 'regexp)
 131
 132 (defcustom gnus-cite-ignore-quoted-from t
 133   "Non-nil means don't regard lines beginning with \">From \" as cited text.
 134 Those lines may have been quoted by MTAs in order not to mix up with
 135 the envelope From line."
 136   :version "22.1"
 137   :group 'gnus-cite
 138   :type 'boolean)
 139
 140 (defface gnus-cite-attribution '((t (:italic t)))
 141   "Face used for attribution lines."
 142   :group 'gnus-cite)
 143 ;; backward-compatibility alias
 144 (put 'gnus-cite-attribution-face 'face-alias 'gnus-cite-attribution)
 145 (put 'gnus-cite-attribution-face 'obsolete-face "22.1")
 146
 147 (defcustom gnus-cite-attribution-face 'gnus-cite-attribution
 148   "Face used for attribution lines.
 149 It is merged with the face for the cited text belonging to the attribution."
 150   :version "22.1"
 151   :group 'gnus-cite
 152   :type 'face)
 153
 154 (defface gnus-cite-1 '((((class color)
 155                          (background dark))
 156                         (:foreground "light blue"))
 157                        (((class color)
 158                          (background light))
 159                         (:foreground "MidnightBlue"))
 160                        (t
 161                         (:italic t)))
 162   "Citation face."
 163   :group 'gnus-cite)
 164 ;; backward-compatibility alias
 165 (put 'gnus-cite-face-1 'face-alias 'gnus-cite-1)
 166 (put 'gnus-cite-face-1 'obsolete-face "22.1")
 167
 168 (defface gnus-cite-2 '((((class color)
 169                          (background dark))
 170                         (:foreground "light cyan"))
 171                        (((class color)
 172                          (background light))
 173                         (:foreground "firebrick"))
 174                        (t
 175                         (:italic t)))
 176   "Citation face."
 177   :group 'gnus-cite)
 178 ;; backward-compatibility alias
 179 (put 'gnus-cite-face-2 'face-alias 'gnus-cite-2)
 180 (put 'gnus-cite-face-2 'obsolete-face "22.1")
 181
 182 (defface gnus-cite-3 '((((class color)
 183                          (background dark))
 184                         (:foreground "light yellow"))
 185                        (((class color)
 186                          (background light))
 187                         (:foreground "dark green"))
 188                        (t
 189                         (:italic t)))
 190   "Citation face."
 191   :group 'gnus-cite)
 192 ;; backward-compatibility alias
 193 (put 'gnus-cite-face-3 'face-alias 'gnus-cite-3)
 194 (put 'gnus-cite-face-3 'obsolete-face "22.1")
 195
 196 (defface gnus-cite-4 '((((class color)
 197                          (background dark))
 198                         (:foreground "light pink"))
 199                        (((class color)
 200                          (background light))
 201                         (:foreground "OrangeRed"))
 202                        (t
 203                         (:italic t)))
 204   "Citation face."
 205   :group 'gnus-cite)
 206 ;; backward-compatibility alias
 207 (put 'gnus-cite-face-4 'face-alias 'gnus-cite-4)
 208 (put 'gnus-cite-face-4 'obsolete-face "22.1")
 209
 210 (defface gnus-cite-5 '((((class color)
 211                          (background dark))
 212                         (:foreground "pale green"))
 213                        (((class color)
 214                          (background light))
 215                         (:foreground "dark khaki"))
 216                        (t
 217                         (:italic t)))
 218   "Citation face."
 219   :group 'gnus-cite)
 220 ;; backward-compatibility alias
 221 (put 'gnus-cite-face-5 'face-alias 'gnus-cite-5)
 222 (put 'gnus-cite-face-5 'obsolete-face "22.1")
 223
 224 (defface gnus-cite-6 '((((class color)
 225                          (background dark))
 226                         (:foreground "beige"))
 227                        (((class color)
 228                          (background light))
 229                         (:foreground "dark violet"))
 230                        (t
 231                         (:italic t)))
 232   "Citation face."
 233   :group 'gnus-cite)
 234 ;; backward-compatibility alias
 235 (put 'gnus-cite-face-6 'face-alias 'gnus-cite-6)
 236 (put 'gnus-cite-face-6 'obsolete-face "22.1")
 237
 238 (defface gnus-cite-7 '((((class color)
 239                          (background dark))
 240                         (:foreground "orange"))
 241                        (((class color)
 242                          (background light))
 243                         (:foreground "SteelBlue4"))
 244                        (t
 245                         (:italic t)))
 246   "Citation face."
 247   :group 'gnus-cite)
 248 ;; backward-compatibility alias
 249 (put 'gnus-cite-face-7 'face-alias 'gnus-cite-7)
 250 (put 'gnus-cite-face-7 'obsolete-face "22.1")
 251
 252 (defface gnus-cite-8 '((((class color)
 253                          (background dark))
 254                         (:foreground "magenta"))
 255                        (((class color)
 256                          (background light))
 257                         (:foreground "magenta"))
 258                        (t
 259                         (:italic t)))
 260   "Citation face."
 261   :group 'gnus-cite)
 262 ;; backward-compatibility alias
 263 (put 'gnus-cite-face-8 'face-alias 'gnus-cite-8)
 264 (put 'gnus-cite-face-8 'obsolete-face "22.1")
 265
 266 (defface gnus-cite-9 '((((class color)
 267                          (background dark))
 268                         (:foreground "violet"))
 269                        (((class color)
 270                          (background light))
 271                         (:foreground "violet"))
 272                        (t
 273                         (:italic t)))
 274   "Citation face."
 275   :group 'gnus-cite)
 276 ;; backward-compatibility alias
 277 (put 'gnus-cite-face-9 'face-alias 'gnus-cite-9)
 278 (put 'gnus-cite-face-9 'obsolete-face "22.1")
 279
 280 (defface gnus-cite-10 '((((class color)
 281                           (background dark))
 282                          (:foreground "plum1"))
 283                         (((class color)
 284                           (background light))
 285                          (:foreground "medium purple"))
 286                         (t
 287                          (:italic t)))
 288   "Citation face."
 289   :group 'gnus-cite)
 290 ;; backward-compatibility alias
 291 (put 'gnus-cite-face-10 'face-alias 'gnus-cite-10)
 292 (put 'gnus-cite-face-10 'obsolete-face "22.1")
 293
 294 (defface gnus-cite-11 '((((class color)
 295                           (background dark))
 296                          (:foreground "turquoise"))
 297                         (((class color)
 298                           (background light))
 299                          (:foreground "turquoise"))
 300                         (t
 301                          (:italic t)))
 302   "Citation face."
 303   :group 'gnus-cite)
 304 ;; backward-compatibility alias
 305 (put 'gnus-cite-face-11 'face-alias 'gnus-cite-11)
 306 (put 'gnus-cite-face-11 'obsolete-face "22.1")
 307
 308 (defcustom gnus-cite-face-list
 309   '(gnus-cite-1 gnus-cite-2 gnus-cite-3 gnus-cite-4 gnus-cite-5 gnus-cite-6
 310                 gnus-cite-7 gnus-cite-8 gnus-cite-9 gnus-cite-10 gnus-cite-11)
 311   "*List of faces used for highlighting citations.
 312
 313 When there are citations from multiple articles in the same message,
 314 Gnus will try to give each citation from each article its own face.
 315 This should make it easier to see who wrote what."
 316   :group 'gnus-cite
 317   :type '(repeat face)
 318   :set (lambda (symbol value)
 319          (prog1
 320              (custom-set-default symbol value)
 321            (if (boundp 'gnus-message-max-citation-depth)
 322                (setq gnus-message-max-citation-depth (length value)))
 323            (if (boundp 'gnus-message-citation-keywords)
 324                (setq gnus-message-citation-keywords
 325                      `((gnus-message-search-citation-line
 326                         ,@(let ((list nil)
 327                                 (count 1))
 328                             (dolist (face value (nreverse list))
 329                               (push (list count (list 'quote face) 'prepend t)
 330                                     list)
 331                               (setq count (1+ count)))))))))))
 332
 333 (defcustom gnus-cite-hide-percentage 50
 334   "Only hide excess citation if above this percentage of the body."
 335   :group 'gnus-cite
 336   :type 'number)
 337
 338 (defcustom gnus-cite-hide-absolute 10
 339   "Only hide excess citation if above this number of lines in the body."
 340   :group 'gnus-cite
 341   :type 'integer)
 342
 343 (defcustom gnus-cite-blank-line-after-header t
 344   "If non-nil, put a blank line between the citation header and the button."
 345   :group 'gnus-cite
 346   :type 'boolean)
 347
 348 ;; This has to go here because its default value depends on
 349 ;; gnus-cite-face-list.
 350 (defcustom gnus-article-boring-faces (cons 'gnus-signature gnus-cite-face-list)
 351   "List of faces that are not worth reading.
 352 If an article has more pages below the one you are looking at, but
 353 nothing on those pages is a word of at least three letters that is not
 354 in a boring face, then the pages will be skipped."
 355   :type '(repeat face)
 356   :group 'gnus-article-hiding)
 357
 358 ;;; Internal Variables:
 359
 360 (defvar gnus-cite-article nil)
 361 (defvar gnus-cite-overlay-list nil)
 362
 363 (defvar gnus-cite-prefix-alist nil)
 364 ;; Alist of citation prefixes.
 365 ;; The cdr is a list of lines with that prefix.
 366
 367 (defvar gnus-cite-attribution-alist nil)
 368 ;; Alist of attribution lines.
 369 ;; The car is a line number.
 370 ;; The cdr is the prefix for the citation started by that line.
 371
 372 (defvar gnus-cite-loose-prefix-alist nil)
 373 ;; Alist of citation prefixes that have no matching attribution.
 374 ;; The cdr is a list of lines with that prefix.
 375
 376 (defvar gnus-cite-loose-attribution-alist nil)
 377 ;; Alist of attribution lines that have no matching citation.
 378 ;; Each member has the form (WROTE IN PREFIX TAG), where
 379 ;; WROTE: is the attribution line number
 380 ;; IN: is the line number of the previous line if part of the same attribution,
 381 ;; PREFIX: Is the citation prefix of the attribution line(s), and
 382 ;; TAG: Is a Supercite tag, if any.
 383
 384 (defvar gnus-cited-opened-text-button-line-format-alist
 385   `((?b (marker-position beg) ?d)
 386     (?e (marker-position end) ?d)
 387     (?n (count-lines beg end) ?d)
 388     (?l (- end beg) ?d)))
 389 (defvar gnus-cited-opened-text-button-line-format-spec nil)
 390 (defvar gnus-cited-closed-text-button-line-format-alist
 391   gnus-cited-opened-text-button-line-format-alist)
 392 (defvar gnus-cited-closed-text-button-line-format-spec nil)
 393
 394
 395 ;;; Commands:
 396
 397 (defun gnus-article-highlight-citation (&optional force same-buffer)
 398   "Highlight cited text.
 399 Each citation in the article will be highlighted with a different face.
 400 The faces are taken from `gnus-cite-face-list'.
 401 Attribution lines are highlighted with the same face as the
 402 corresponding citation merged with the face `gnus-cite-attribution'.
 403
 404 Text is considered cited if at least `gnus-cite-minimum-match-count'
 405 lines matches `message-cite-prefix-regexp' with the same prefix.
 406
 407 Lines matching `gnus-cite-attribution-suffix' and perhaps
 408 `gnus-cite-attribution-prefix' are considered attribution lines."
 409   (interactive (list 'force))
 410   (with-current-buffer (if same-buffer (current-buffer) gnus-article-buffer)
 411     (gnus-cite-parse-maybe force)
 412     (let ((buffer-read-only nil)
 413           (alist gnus-cite-prefix-alist)
 414           (faces gnus-cite-face-list)
 415           (inhibit-point-motion-hooks t)
 416           face entry prefix skip numbers number face-alist)
 417       ;; Loop through citation prefixes.
 418       (while alist
 419         (setq entry (car alist)
 420               alist (cdr alist)
 421               prefix (car entry)
 422               numbers (cdr entry)
 423               face (car faces)
 424               faces (or (cdr faces) gnus-cite-face-list)
 425               face-alist (cons (cons prefix face) face-alist))
 426         (while numbers
 427           (setq number (car numbers)
 428                 numbers (cdr numbers))
 429           (and (not (assq number gnus-cite-attribution-alist))
 430                (not (assq number gnus-cite-loose-attribution-alist))
 431                (gnus-cite-add-face number prefix face))))
 432       ;; Loop through attribution lines.
 433       (setq alist gnus-cite-attribution-alist)
 434       (while alist
 435         (setq entry (car alist)
 436               alist (cdr alist)
 437               number (car entry)
 438               prefix (cdr entry)
 439               skip (gnus-cite-find-prefix number)
 440               face (cdr (assoc prefix face-alist)))
 441         ;; Add attribution button.
 442         (goto-char (point-min))
 443         (forward-line (1- number))
 444         (when (re-search-forward gnus-cite-attribution-suffix
 445                                  (point-at-eol)
 446                                  t)
 447           (gnus-article-add-button (match-beginning 1) (match-end 1)
 448                                    'gnus-cite-toggle prefix))
 449         ;; Highlight attribution line.
 450         (gnus-cite-add-face number skip face)
 451         (gnus-cite-add-face number skip gnus-cite-attribution-face))
 452       ;; Loop through attribution lines.
 453       (setq alist gnus-cite-loose-attribution-alist)
 454       (while alist
 455         (setq entry (car alist)
 456               alist (cdr alist)
 457               number (car entry)
 458               skip (gnus-cite-find-prefix number))
 459         (gnus-cite-add-face number skip gnus-cite-attribution-face)))))
 460
 461 (defun gnus-dissect-cited-text ()
 462   "Dissect the article buffer looking for cited text."
 463   (with-current-buffer gnus-article-buffer
 464     (gnus-cite-parse-maybe nil t)
 465     (let ((alist gnus-cite-prefix-alist)
 466           prefix numbers number marks m)
 467       ;; Loop through citation prefixes.
 468       (while alist
 469         (setq numbers (pop alist)
 470               prefix (pop numbers))
 471         (while numbers
 472           (setq number (pop numbers))
 473           (goto-char (point-min))
 474           (forward-line number)
 475           (push (cons (point-marker) "") marks)
 476           (while (and numbers
 477                       (= (1- number) (car numbers)))
 478             (setq number (pop numbers)))
 479           (goto-char (point-min))
 480           (forward-line (1- number))
 481           (push (cons (point-marker) prefix) marks)))
 482       ;; Skip to the beginning of the body.
 483       (article-goto-body)
 484       (push (cons (point-marker) "") marks)
 485       ;; Find the end of the body.
 486       (goto-char (point-max))
 487       (gnus-article-search-signature)
 488       (push (cons (point-marker) "") marks)
 489       ;; Sort the marks.
 490       (setq marks (sort marks 'car-less-than-car))
 491       (let ((omarks marks))
 492         (setq marks nil)
 493         (while (cdr omarks)
 494           (if (= (caar omarks) (caadr omarks))
 495               (progn
 496                 (unless (equal (cdar omarks) "")
 497                   (push (car omarks) marks))
 498                 (unless (equal (cdadr omarks) "")
 499                   (push (cadr omarks) marks))
 500                 (unless (and (equal (cdar omarks) "")
 501                              (equal (cdadr omarks) "")
 502                              (not (cddr omarks)))
 503                   (setq omarks (cdr omarks))))
 504             (push (car omarks) marks))
 505           (setq omarks (cdr omarks)))
 506         (when (car omarks)
 507           (push (car omarks) marks))
 508         (setq marks (setq m (nreverse marks)))
 509         (while (cddr m)
 510           (if (and (equal (cdadr m) "")
 511                    (equal (cdar m) (cdaddr m))
 512                    (goto-char (caadr m))
 513                    (forward-line 1)
 514                    (= (point) (caaddr m)))
 515               (setcdr m (cdddr m))
 516             (setq m (cdr m))))
 517         marks))))
 518
 519 (defun gnus-article-fill-cited-long-lines ()
 520   (gnus-article-fill-cited-article nil t))
 521
 522 (defun gnus-article-fill-cited-article (&optional width long-lines)
 523   "Do word wrapping in the current article.
 524 If WIDTH (the numerical prefix), use that text width when
 525 filling.  If LONG-LINES, only fill sections that have lines
 526 longer than the frame width."
 527   (interactive "P")
 528   (with-current-buffer gnus-article-buffer
 529     (let ((buffer-read-only nil)
 530           (inhibit-point-motion-hooks t)
 531           (marks (gnus-dissect-cited-text))
 532           (adaptive-fill-mode nil)
 533           (filladapt-mode nil)
 534           (fill-column (if width (prefix-numeric-value width) fill-column)))
 535       (save-restriction
 536         (while (cdr marks)
 537           (narrow-to-region (caar marks) (caadr marks))
 538           (let ((adaptive-fill-regexp
 539                  (concat "^" (regexp-quote (cdar marks)) " *"))
 540                 (fill-prefix
 541                  (if (string= (cdar marks) "") ""
 542                    (concat (cdar marks) " ")))
 543                 (do-fill (not long-lines))
 544                 use-hard-newlines)
 545             (unless do-fill
 546               (setq do-fill (gnus-article-foldable-buffer (cdar marks))))
 547             ;; Note: the XEmacs version of `fill-region' inserts a newline
 548             ;; unless the region ends with a newline.
 549             (when do-fill
 550               (if (not long-lines)
 551                   (fill-region (point-min) (point-max))
 552                 (goto-char (point-min))
 553                 (while (not (eobp))
 554                   (end-of-line)
 555                   (when (prog1
 556                             (> (current-column) (window-width))
 557                           (forward-line 1))
 558                     (save-restriction
 559                       (narrow-to-region (line-beginning-position 0) (point))
 560                       (fill-region (point-min) (point-max))))))))
 561           (set-marker (caar marks) nil)
 562           (setq marks (cdr marks)))
 563         (when marks
 564           (set-marker (caar marks) nil))
 565         ;; All this information is now incorrect.
 566         (setq gnus-cite-prefix-alist nil
 567               gnus-cite-attribution-alist nil
 568               gnus-cite-loose-prefix-alist nil
 569               gnus-cite-loose-attribution-alist nil
 570               gnus-cite-article nil)))))
 571
 572 (defun gnus-article-foldable-buffer (prefix)
 573   (let ((do-fill nil)
 574         columns)
 575     (goto-char (point-min))
 576     (while (not (eobp))
 577       (unless (> (length prefix) (- (point-max) (point)))
 578         (forward-char (length prefix)))
 579       (skip-chars-forward " \t")
 580       (unless (eolp)
 581         (let ((elem (assq (current-column) columns)))
 582           (unless elem
 583             (setq elem (cons (current-column) 0))
 584             (push elem columns))
 585           (setcdr elem (1+ (cdr elem)))))
 586       (end-of-line)
 587       (when (> (current-column) (window-width))
 588         (setq do-fill t))
 589       (forward-line 1))
 590     (and do-fill
 591          ;; We know know that there are long lines here, but does this look
 592          ;; like code?  Check for ragged edges on the left.
 593          (< (length columns) 3))))
 594
 595 (defun gnus-article-hide-citation (&optional arg force)
 596   "Toggle hiding of all cited text except attribution lines.
 597 See the documentation for `gnus-article-highlight-citation'.
 598 If given a negative prefix, always show; if given a positive prefix,
 599 always hide."
 600   (interactive (append (gnus-article-hidden-arg) (list 'force)))
 601   (gnus-set-format 'cited-opened-text-button t)
 602   (gnus-set-format 'cited-closed-text-button t)
 603   (with-current-buffer gnus-article-buffer
 604     (let ((buffer-read-only nil)
 605           marks
 606           (inhibit-point-motion-hooks t)
 607           (props (nconc (list 'article-type 'cite)
 608                         gnus-hidden-properties))
 609           (point (point-min))
 610           found beg end start)
 611       (while (setq point
 612                    (text-property-any point (point-max)
 613                                       'gnus-callback
 614                                       'gnus-article-toggle-cited-text))
 615         (setq found t)
 616         (goto-char point)
 617         (gnus-article-toggle-cited-text
 618          (get-text-property point 'gnus-data) arg)
 619         (forward-line 1)
 620         (setq point (point)))
 621       (unless found
 622         (setq marks (gnus-dissect-cited-text))
 623         (while marks
 624           (setq beg nil
 625                 end nil)
 626           (while (and marks (string= (cdar marks) ""))
 627             (setq marks (cdr marks)))
 628           (when marks
 629             (setq beg (caar marks)))
 630           (while (and marks (not (string= (cdar marks) "")))
 631             (setq marks (cdr marks)))
 632           (when marks
 633             (setq end (caar marks)))
 634           ;; Skip past lines we want to leave visible.
 635           (when (and beg end gnus-cited-lines-visible)
 636             (goto-char beg)
 637             (forward-line (if (consp gnus-cited-lines-visible)
 638                               (car gnus-cited-lines-visible)
 639                             gnus-cited-lines-visible))
 640             (if (>= (point) end)
 641                 (setq beg nil)
 642               (setq beg (point-marker))
 643               (when (consp gnus-cited-lines-visible)
 644                 (goto-char end)
 645                 (forward-line (- (cdr gnus-cited-lines-visible)))
 646                 (if (<= (point) beg)
 647                     (setq beg nil)
 648                   (setq end (point-marker))))))
 649           (when (and beg end)
 650             (gnus-add-wash-type 'cite)
 651             ;; We use markers for the end-points to facilitate later
 652             ;; wrapping and mangling of text.
 653             (setq beg (set-marker (make-marker) beg)
 654                   end (set-marker (make-marker) end))
 655             (gnus-add-text-properties-when 'article-type nil beg end props)
 656             (goto-char beg)
 657             (when (and gnus-cite-blank-line-after-header
 658                        (not (save-excursion (search-backward "\n\n" nil t))))
 659               (insert "\n"))
 660             (put-text-property
 661              (setq start (point-marker))
 662              (progn
 663                (gnus-article-add-button
 664                 (point)
 665                 (progn (eval gnus-cited-closed-text-button-line-format-spec)
 666                        (point))
 667                 `gnus-article-toggle-cited-text
 668                 (list (cons beg end) start))
 669                (point))
 670              'article-type 'annotation)
 671             (set-marker beg (point))))))))
 672
 673 (defun gnus-article-toggle-cited-text (args &optional arg)
 674   "Toggle hiding the text in REGION.
 675 ARG can be nil or a number.  Positive means hide, negative
 676 means show, nil means toggle."
 677   (let* ((region (car args))
 678          (beg (car region))
 679          (end (cdr region))
 680          (start (cadr args))
 681          (hidden
 682           (text-property-any beg (1- end) 'article-type 'cite))
 683          (inhibit-point-motion-hooks t)
 684          buffer-read-only)
 685     (when (or (null arg)
 686               (zerop arg)
 687               (and (> arg 0) (not hidden))
 688               (and (< arg 0) hidden))
 689       (if hidden
 690           (progn
 691             ;; Can't remove 'cite from g-a-wash-types here because
 692             ;; multiple citations may be hidden -jas
 693             (gnus-remove-text-properties-when
 694              'article-type 'cite beg end
 695              (cons 'article-type (cons 'cite
 696                                        gnus-hidden-properties))))
 697         (gnus-add-wash-type 'cite)
 698         (gnus-add-text-properties-when
 699          'article-type nil beg end
 700          (cons 'article-type (cons 'cite
 701                                    gnus-hidden-properties))))
 702       (let ((gnus-article-mime-handle-alist-1 gnus-article-mime-handle-alist))
 703         (gnus-set-mode-line 'article))
 704       (save-excursion
 705         (goto-char start)
 706         (gnus-delete-line)
 707         (put-text-property
 708          (point)
 709          (progn
 710            (gnus-article-add-button
 711             (point)
 712             (progn (eval
 713                     (if hidden
 714                         gnus-cited-opened-text-button-line-format-spec
 715                       gnus-cited-closed-text-button-line-format-spec))
 716                    (point))
 717             `gnus-article-toggle-cited-text
 718             args)
 719            (point))
 720          'article-type 'annotation)))))
 721
 722 (defun gnus-article-hide-citation-maybe (&optional arg force)
 723   "Toggle hiding of cited text that has an attribution line.
 724 If given a negative prefix, always show; if given a positive prefix,
 725 always hide.
 726 This will do nothing unless at least `gnus-cite-hide-percentage'
 727 percent and at least `gnus-cite-hide-absolute' lines of the body is
 728 cited text with attributions.  When called interactively, these two
 729 variables are ignored.
 730 See also the documentation for `gnus-article-highlight-citation'."
 731   (interactive (append (gnus-article-hidden-arg) '(force)))
 732   (with-current-buffer gnus-article-buffer
 733     (gnus-delete-wash-type 'cite)
 734     (unless (gnus-article-check-hidden-text 'cite arg)
 735       (save-excursion
 736         (gnus-cite-parse-maybe force)
 737         (article-goto-body)
 738         (let ((start (point))
 739               (atts gnus-cite-attribution-alist)
 740               (buffer-read-only nil)
 741               (inhibit-point-motion-hooks t)
 742               (hidden 0)
 743               total)
 744           (goto-char (point-max))
 745           (gnus-article-search-signature)
 746           (setq total (count-lines start (point)))
 747           (while atts
 748             (setq hidden (+ hidden (length (cdr (assoc (cdar atts)
 749                                                        gnus-cite-prefix-alist))))
 750                   atts (cdr atts)))
 751           (when (or force
 752                     (and (> (* 100 hidden) (* gnus-cite-hide-percentage total))
 753                          (> hidden gnus-cite-hide-absolute)))
 754             (gnus-add-wash-type 'cite)
 755             (setq atts gnus-cite-attribution-alist)
 756             (while atts
 757               (setq total (cdr (assoc (cdar atts) gnus-cite-prefix-alist))
 758                     atts (cdr atts))
 759               (while total
 760                 (setq hidden (car total)
 761                       total (cdr total))
 762                 (goto-char (point-min))
 763                 (forward-line (1- hidden))
 764                 (unless (assq hidden gnus-cite-attribution-alist)
 765                   (gnus-add-text-properties
 766                    (point) (progn (forward-line 1) (point))
 767                    (nconc (list 'article-type 'cite)
 768                           gnus-hidden-properties)))))))))
 769     (gnus-set-mode-line 'article)))
 770
 771 (defun gnus-article-hide-citation-in-followups ()
 772   "Hide cited text in non-root articles."
 773   (interactive)
 774   (with-current-buffer gnus-article-buffer
 775     (let ((article (cdr gnus-article-current)))
 776       (unless (with-current-buffer gnus-summary-buffer
 777                 (gnus-article-displayed-root-p article))
 778         (gnus-article-hide-citation)))))
 779
 780 ;;; Internal functions:
 781
 782 (defun gnus-cite-parse-maybe (&optional force no-overlay)
 783   "Always parse the buffer."
 784   (gnus-cite-localize)
 785   ;;Reset parser information.
 786   (setq gnus-cite-prefix-alist nil
 787         gnus-cite-attribution-alist nil
 788         gnus-cite-loose-prefix-alist nil
 789         gnus-cite-loose-attribution-alist nil)
 790   (unless no-overlay
 791     (gnus-cite-delete-overlays))
 792   ;; Parse if not too large.
 793   (if (and gnus-cite-parse-max-size
 794            (> (buffer-size) gnus-cite-parse-max-size))
 795       ()
 796     (setq gnus-cite-article (cons (car gnus-article-current)
 797                                   (cdr gnus-article-current)))
 798     (gnus-cite-parse-wrapper)))
 799
 800 (defun gnus-cite-delete-overlays ()
 801   (dolist (overlay gnus-cite-overlay-list)
 802     (ignore-errors
 803       (when (or (not (gnus-overlay-end overlay))
 804                 (and (>= (gnus-overlay-end overlay) (point-min))
 805                      (<= (gnus-overlay-end overlay) (point-max))))
 806         (setq gnus-cite-overlay-list (delete overlay gnus-cite-overlay-list))
 807         (ignore-errors
 808           (gnus-delete-overlay overlay))))))
 809
 810 (defun gnus-cite-parse-wrapper ()
 811   ;; Wrap chopped gnus-cite-parse.
 812   (article-goto-body)
 813   (let ((inhibit-point-motion-hooks t))
 814     (save-excursion
 815       (gnus-cite-parse-attributions))
 816     (save-excursion
 817       (gnus-cite-parse))
 818     (save-excursion
 819       (gnus-cite-connect-attributions))))
 820
 821 (defun gnus-cite-parse ()
 822   ;; Parse and connect citation prefixes and attribution lines.
 823
 824   ;; Parse current buffer searching for citation prefixes.
 825   (let ((line (1+ (count-lines (point-min) (point))))
 826         (case-fold-search t)
 827         (max (save-excursion
 828                (goto-char (point-max))
 829                (gnus-article-search-signature)
 830                (point)))
 831         (prefix-regexp (concat "^\\(" message-cite-prefix-regexp "\\)"))
 832         alist entry start begin end numbers prefix guess-limit)
 833     ;; Get all potential prefixes in `alist'.
 834     (while (< (point) max)
 835       ;; Each line.
 836       (setq begin (point)
 837             guess-limit (progn (skip-chars-forward "^> \t\r\n") (point))
 838             end (point-at-bol 2)
 839             start end)
 840       (goto-char begin)
 841       ;; Ignore standard Supercite attribution prefix.
 842       (when (and (< guess-limit (+ begin gnus-cite-max-prefix))
 843                  (looking-at gnus-supercite-regexp))
 844         (if (match-end 1)
 845             (setq end (1+ (match-end 1)))
 846           (setq end (1+ begin))))
 847       ;; Ignore very long prefixes.
 848       (when (> end (+ begin gnus-cite-max-prefix))
 849         (setq end (+ begin gnus-cite-max-prefix)))
 850       ;; Ignore quoted envelope From_.
 851       (when (and gnus-cite-ignore-quoted-from
 852                  (prog2
 853                      (setq case-fold-search nil)
 854                      (looking-at ">From ")
 855                    (setq case-fold-search t)))
 856         (setq end (1+ begin)))
 857       (while (re-search-forward prefix-regexp (1- end) t)
 858         ;; Each prefix.
 859         (setq end (match-end 0)
 860               prefix (buffer-substring begin end))
 861         (set-text-properties 0 (length prefix) nil prefix)
 862         (setq entry (assoc prefix alist))
 863         (if entry
 864             (setcdr entry (cons line (cdr entry)))
 865           (push (list prefix line) alist))
 866         (goto-char begin))
 867       (goto-char start)
 868       (setq line (1+ line)))
 869     ;; Horrible special case for some Microsoft mailers.
 870     (goto-char (point-min))
 871     (setq start t begin nil entry nil)
 872     (while start
 873       ;; Assume this search ends up at the beginning of a line.
 874       (if (re-search-forward gnus-cite-unsightly-citation-regexp max t)
 875           (progn
 876             (when (number-or-marker-p start)
 877               (setq begin (count-lines (point-min) start)
 878                     end (count-lines (point-min) (match-beginning 0))))
 879             (setq start (match-end 0)))
 880         (when (number-or-marker-p start)
 881           (setq begin (count-lines (point-min) start)
 882                 end (count-lines (point-min) max)))
 883         (setq start nil))
 884       (when begin
 885         (while (< begin end)
 886           ;; Need to do 1+ because we're in the bol.
 887           (push (setq begin (1+ begin)) entry))))
 888     (when entry
 889       (push (cons "" entry) alist))
 890     ;; We got all the potential prefixes.  Now create
 891     ;; `gnus-cite-prefix-alist' containing the oldest prefix for each
 892     ;; line that appears at least `gnus-cite-minimum-match-count'
 893     ;; times.  First sort them by length.  Longer is older.
 894     (setq alist (sort alist (lambda (a b)
 895                               (> (length (car a)) (length (car b))))))
 896     (while alist
 897       (setq entry (car alist)
 898             prefix (car entry)
 899             numbers (cdr entry)
 900             alist (cdr alist))
 901       (cond ((null numbers)
 902              ;; No lines with this prefix that wasn't also part of
 903              ;; a longer prefix.
 904              )
 905             ((< (length numbers) gnus-cite-minimum-match-count)
 906              ;; Too few lines with this prefix.  We keep it a bit
 907              ;; longer in case it is an exact match for an attribution
 908              ;; line, but we don't remove the line from other
 909              ;; prefixes.
 910              (push entry gnus-cite-prefix-alist))
 911             (t
 912              (push entry
 913                    gnus-cite-prefix-alist)
 914              ;; Remove articles from other prefixes.
 915              (let ((loop alist)
 916                    current)
 917                (while loop
 918                  (setq current (car loop)
 919                        loop (cdr loop))
 920                  (setcdr current
 921                          (gnus-set-difference (cdr current) numbers)))))))))
 922
 923 (defun gnus-cite-parse-attributions ()
 924   (let (al-alist)
 925     ;; Parse attributions
 926     (while (re-search-forward gnus-cite-attribution-suffix (point-max) t)
 927       (let* ((start (match-beginning 0))
 928              (end (match-end 0))
 929              (wrote (count-lines (point-min) end))
 930              (prefix (gnus-cite-find-prefix wrote))
 931              ;; Check previous line for an attribution leader.
 932              (tag (progn
 933                     (beginning-of-line 1)
 934                     (when (looking-at gnus-supercite-secondary-regexp)
 935                       (buffer-substring (match-beginning 1)
 936                                         (match-end 1)))))
 937              (in (progn
 938                    (goto-char start)
 939                    (and (re-search-backward gnus-cite-attribution-prefix
 940                                             (save-excursion
 941                                               (beginning-of-line 0)
 942                                               (point))
 943                                             t)
 944                         (not (re-search-forward gnus-cite-attribution-suffix
 945                                                 start t))
 946                         (count-lines (point-min) (1+ (point)))))))
 947         (when (eq wrote in)
 948           (setq in nil))
 949         (goto-char end)
 950         ;; don't add duplicates
 951         (let ((al (buffer-substring (save-excursion (beginning-of-line 0)
 952                                                     (1+ (point)))
 953                                     end)))
 954           (when (not (assoc al al-alist))
 955             (push (list wrote in prefix tag)
 956                   gnus-cite-loose-attribution-alist)
 957             (push (cons al t) al-alist)))))))
 958
 959 (defun gnus-cite-connect-attributions ()
 960   ;; Connect attributions to citations
 961
 962   ;; No citations have been connected to attribution lines yet.
 963   (setq gnus-cite-loose-prefix-alist (append gnus-cite-prefix-alist nil))
 964
 965   ;; Parse current buffer searching for attribution lines.
 966   ;; Find exact supercite citations.
 967   (gnus-cite-match-attributions 'small nil
 968                                 (lambda (prefix tag)
 969                                   (when tag
 970                                     (concat "\\`"
 971                                             (regexp-quote prefix) "[ \t]*"
 972                                             (regexp-quote tag) ">"))))
 973   ;; Find loose supercite citations after attributions.
 974   (gnus-cite-match-attributions 'small t
 975                                 (lambda (prefix tag)
 976                                   (when tag
 977                                     (concat "\\<"
 978                                             (regexp-quote tag)
 979                                             "\\>"))))
 980   ;; Find loose supercite citations anywhere.
 981   (gnus-cite-match-attributions 'small nil
 982                                 (lambda (prefix tag)
 983                                   (when tag
 984                                     (concat "\\<"
 985                                             (regexp-quote tag)
 986                                             "\\>"))))
 987   ;; Find nested citations after attributions.
 988   (gnus-cite-match-attributions 'small-if-unique t
 989                                 (lambda (prefix tag)
 990                                   (concat "\\`" (regexp-quote prefix) ".+")))
 991   ;; Find nested citations anywhere.
 992   (gnus-cite-match-attributions 'small nil
 993                                 (lambda (prefix tag)
 994                                   (concat "\\`" (regexp-quote prefix) ".+")))
 995   ;; Remove loose prefixes with too few lines.
 996   (let ((alist gnus-cite-loose-prefix-alist)
 997         entry)
 998     (while alist
 999       (setq entry (car alist)
1000             alist (cdr alist))
1001       (when (< (length (cdr entry)) gnus-cite-minimum-match-count)
1002         (setq gnus-cite-prefix-alist
1003               (delq entry gnus-cite-prefix-alist)
1004               gnus-cite-loose-prefix-alist
1005               (delq entry gnus-cite-loose-prefix-alist)))))
1006   ;; Find flat attributions.
1007   (gnus-cite-match-attributions 'first t nil)
1008   ;; Find any attributions (are we getting desperate yet?).
1009   (gnus-cite-match-attributions 'first nil nil))
1010
1011 (defun gnus-cite-match-attributions (sort after fun)
1012   ;; Match all loose attributions and citations (SORT AFTER FUN) .
1013   ;;
1014   ;; If SORT is `small', the citation with the shortest prefix will be
1015   ;; used, if it is `first' the first prefix will be used, if it is
1016   ;; `small-if-unique' the shortest prefix will be used if the
1017   ;; attribution line does not share its own prefix with other
1018   ;; loose attribution lines, otherwise the first prefix will be used.
1019   ;;
1020   ;; If AFTER is non-nil, only citations after the attribution line
1021   ;; will be considered.
1022   ;;
1023   ;; If FUN is non-nil, it will be called with the arguments (WROTE
1024   ;; PREFIX TAG) and expected to return a regular expression.  Only
1025   ;; citations whose prefix matches the regular expression will be
1026   ;; considered.
1027   ;;
1028   ;; WROTE is the attribution line number.
1029   ;; PREFIX is the attribution line prefix.
1030   ;; TAG is the Supercite tag on the attribution line.
1031   (let ((atts gnus-cite-loose-attribution-alist)
1032         (case-fold-search t)
1033         att wrote in prefix tag regexp limit smallest best size)
1034     (while atts
1035       (setq att (car atts)
1036             atts (cdr atts)
1037             wrote (nth 0 att)
1038             in (nth 1 att)
1039             prefix (nth 2 att)
1040             tag (nth 3 att)
1041             regexp (if fun (funcall fun prefix tag) "")
1042             size (cond ((eq sort 'small) t)
1043                        ((eq sort 'first) nil)
1044                        (t (< (length (gnus-cite-find-loose prefix)) 2)))
1045             limit (if after wrote -1)
1046             smallest 1000000
1047             best nil)
1048       (let ((cites gnus-cite-loose-prefix-alist)
1049             cite candidate numbers first compare)
1050         (while cites
1051           (setq cite (car cites)
1052                 cites (cdr cites)
1053                 candidate (car cite)
1054                 numbers (cdr cite)
1055                 first (apply 'min numbers)
1056                 compare (if size (length candidate) first))
1057           (and (> first limit)
1058                regexp
1059                (string-match regexp candidate)
1060                (< compare smallest)
1061                (setq best cite
1062                      smallest compare))))
1063       (if (null best)
1064           ()
1065         (setq gnus-cite-loose-attribution-alist
1066               (delq att gnus-cite-loose-attribution-alist))
1067         (push (cons wrote (car best)) gnus-cite-attribution-alist)
1068         (when in
1069           (push (cons in (car best)) gnus-cite-attribution-alist))
1070         (when (memq best gnus-cite-loose-prefix-alist)
1071           (let ((loop gnus-cite-prefix-alist)
1072                 (numbers (cdr best))
1073                 current)
1074             (setq gnus-cite-loose-prefix-alist
1075                   (delq best gnus-cite-loose-prefix-alist))
1076             (while loop
1077               (setq current (car loop)
1078                     loop (cdr loop))
1079               (if (eq current best)
1080                   ()
1081                 (setcdr current (gnus-set-difference (cdr current) numbers))
1082                 (when (null (cdr current))
1083                   (setq gnus-cite-loose-prefix-alist
1084                         (delq current gnus-cite-loose-prefix-alist)
1085                         atts (delq current atts)))))))))))
1086
1087 (defun gnus-cite-find-loose (prefix)
1088   ;; Return a list of loose attribution lines prefixed by PREFIX.
1089   (let* ((atts gnus-cite-loose-attribution-alist)
1090          att line lines)
1091     (while atts
1092       (setq att (car atts)
1093             line (car att)
1094             atts (cdr atts))
1095       (when (string-equal (gnus-cite-find-prefix line) prefix)
1096         (push line lines)))
1097     lines))
1098
1099 (defun gnus-cite-add-face (number prefix face)
1100   ;; At line NUMBER, ignore PREFIX and add FACE to the rest of the line.
1101   (when face
1102     (let ((inhibit-point-motion-hooks t)
1103           from to overlay)
1104       (goto-char (point-min))
1105       (when (zerop (forward-line (1- number)))
1106         (forward-char (length prefix))
1107         (skip-chars-forward " \t")
1108         (setq from (point))
1109         (end-of-line 1)
1110         (skip-chars-backward " \t")
1111         (setq to (point))
1112         (when (< from to)
1113           (push (setq overlay (gnus-make-overlay from to))
1114                 gnus-cite-overlay-list)
1115           (gnus-overlay-put overlay 'evaporate t)
1116           (gnus-overlay-put overlay 'face face))))))
1117
1118 (defun gnus-cite-toggle (prefix)
1119   (with-current-buffer gnus-article-buffer
1120     (gnus-cite-parse-maybe nil t)
1121     (let ((buffer-read-only nil)
1122           (numbers (cdr (assoc prefix gnus-cite-prefix-alist)))
1123           (inhibit-point-motion-hooks t)
1124           number)
1125       (while numbers
1126         (setq number (car numbers)
1127               numbers (cdr numbers))
1128         (goto-char (point-min))
1129         (forward-line (1- number))
1130         (cond ((get-text-property (point) 'invisible)
1131                ;; Can't remove 'cite from g-a-wash-types here because
1132                ;; multiple citations may be hidden -jas
1133                (remove-text-properties (point) (progn (forward-line 1) (point))
1134                                        gnus-hidden-properties))
1135               ((assq number gnus-cite-attribution-alist))
1136               (t
1137                (gnus-add-wash-type 'cite)
1138                (gnus-add-text-properties
1139                 (point) (progn (forward-line 1) (point))
1140                 (nconc (list 'article-type 'cite)
1141                        gnus-hidden-properties))))
1142         (let ((gnus-article-mime-handle-alist-1
1143                gnus-article-mime-handle-alist))
1144           (gnus-set-mode-line 'article))))))
1145
1146 (defun gnus-cite-find-prefix (line)
1147   ;; Return citation prefix for LINE.
1148   (let ((alist gnus-cite-prefix-alist)
1149         (prefix "")
1150         entry)
1151     (while alist
1152       (setq entry (car alist)
1153             alist (cdr alist))
1154       (when (memq line (cdr entry))
1155         (setq prefix (car entry))))
1156     prefix))
1157
1158 (defun gnus-cite-localize ()
1159   "Make the citation variables local to the article buffer."
1160   (let ((vars '(gnus-cite-article
1161                 gnus-cite-overlay-list gnus-cite-prefix-alist
1162                 gnus-cite-attribution-alist gnus-cite-loose-prefix-alist
1163                 gnus-cite-loose-attribution-alist)))
1164     (while vars
1165       (make-local-variable (pop vars)))))
1166
1167 (defun gnus-cited-line-p ()
1168   "Say whether the current line is a cited line."
1169   (save-excursion
1170     (beginning-of-line)
1171     (let ((found nil))
1172       (dolist (prefix (mapcar 'car gnus-cite-prefix-alist))
1173         (when (string= (buffer-substring (point) (+ (length prefix) (point)))
1174                        prefix)
1175           (setq found t)))
1176       found)))
1177
1178
1179 ;; Highlighting of different citation levels in message-mode.
1180 ;; - message-cite-prefix will be overridden if this is enabled.
1181
1182 (defvar gnus-message-max-citation-depth
1183   (length gnus-cite-face-list)
1184   "Maximum supported level of citation.")
1185
1186 (defvar gnus-message-cite-prefix-regexp
1187   (concat "^\\(?:" message-cite-prefix-regexp "\\)"))
1188
1189 (defun gnus-message-search-citation-line (limit)
1190   "Search for a cited line and set match data accordingly.
1191 Returns nil if there is no such line before LIMIT, t otherwise."
1192   (when (re-search-forward gnus-message-cite-prefix-regexp limit t)
1193     (let ((cdepth (min (length (apply 'concat
1194                                       (split-string
1195                                        (match-string-no-properties 0)
1196                                        "[ \t [:alnum:]]+")))
1197                        gnus-message-max-citation-depth))
1198           (mlist (make-list (* (1+ gnus-message-max-citation-depth) 2) nil))
1199           (start (point-at-bol))
1200           (end (point-at-eol)))
1201       (setcar mlist start)
1202       (setcar (cdr mlist) end)
1203       (setcar (nthcdr (* cdepth 2) mlist) start)
1204       (setcar (nthcdr (1+ (* cdepth 2)) mlist) end)
1205       (set-match-data mlist))
1206     t))
1207
1208 (defvar gnus-message-citation-keywords
1209   ;; eval-when-compile ;; This breaks in XEmacs
1210   `((gnus-message-search-citation-line
1211      ,@(let ((list nil)
1212              (count 1))
1213          ;; (require 'gnus-cite)
1214          (dolist (face gnus-cite-face-list (nreverse list))
1215            (push (list count (list 'quote face) 'prepend t) list)
1216            (setq count (1+ count)))))) ;;
1217   "Keywords for highlighting different levels of message citations.")
1218
1219 (defvar font-lock-defaults-computed)
1220 (defvar font-lock-keywords)
1221 (defvar font-lock-set-defaults)
1222
1223 (eval-and-compile
1224   (unless (featurep 'xemacs)
1225     (autoload 'font-lock-set-defaults "font-lock")))
1226
1227 (define-minor-mode gnus-message-citation-mode
1228   "Toggle `gnus-message-citation-mode' in current buffer.
1229 This buffer local minor mode provides additional font-lock support for
1230 nested citations.
1231 With prefix ARG, turn `gnus-message-citation-mode' on if and only if ARG
1232 is positive.
1233 Automatically turn `font-lock-mode' on when `gnus-message-citation-mode'
1234 is turned on."
1235   nil ;; init-value
1236   "" ;; lighter
1237   nil ;; keymap
1238   (when (eq major-mode 'message-mode)
1239     (let ((defaults (car (if (featurep 'xemacs)
1240                              (get 'message-mode 'font-lock-defaults)
1241                            font-lock-defaults)))
1242           default keywords)
1243       (while defaults
1244         (setq default (if (consp defaults)
1245                           (pop defaults)
1246                         (prog1
1247                             defaults
1248                           (setq defaults nil))))
1249         (if gnus-message-citation-mode
1250             ;; `gnus-message-citation-keywords' should be the last
1251             ;; elements of the keywords because the others are unlikely
1252             ;; to have the OVERRIDE flags -- XEmacs applies a keyword
1253             ;; having no OVERRIDE flag to matched text even if it has
1254             ;; already other faces, while Emacs doesn't.
1255             (set (make-local-variable default)
1256                  (append (default-value default)
1257                          gnus-message-citation-keywords))
1258           (kill-local-variable default))))
1259     ;; Force `font-lock-set-defaults' to update `font-lock-keywords'.
1260     (if (featurep 'xemacs)
1261         (progn
1262           (require 'font-lock)
1263           (setq font-lock-defaults-computed nil
1264                 font-lock-keywords nil))
1265       (setq font-lock-set-defaults nil))
1266     (font-lock-set-defaults)
1267     (cond ((symbol-value 'font-lock-mode)
1268            (font-lock-fontify-buffer))
1269           (gnus-message-citation-mode
1270            (font-lock-mode 1)))))
1271
1272 (defun turn-on-gnus-message-citation-mode ()
1273   "Turn on `gnus-message-citation-mode'."
1274   (gnus-message-citation-mode 1))
1275 (defun turn-off-gnus-message-citation-mode ()
1276   "Turn off `gnus-message-citation-mode'."
1277   (gnus-message-citation-mode -1))
1278
1279 (gnus-ems-redefine)
1280
1281 (provide 'gnus-cite)
1282
1283 ;; Local Variables:
1284 ;; coding: iso-8859-1
1285 ;; End:
1286
1287 ;;; gnus-cite.el ends here