summaryrefslogtreecommitdiff
path: root/lisp/gnus/gnus-cite.el
blob: 5a6d6f8f2433762d56dd406d010ce3c9876be9fa (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
;;; gnus-cite.el --- parse citations in articles for Gnus

;; Copyright (C) 1995-2014 Free Software Foundation, Inc.

;; Author: Per Abhiddenware

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

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

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;;; Code:

(eval-when-compile (require 'cl))
(eval-when-compile
  (when (featurep 'xemacs)
    (require 'easy-mmode))) ; for `define-minor-mode'

(require 'gnus)
(require 'gnus-range)
(require 'gnus-art)
(require 'message)	; for message-cite-prefix-regexp

;;; Customization:

(defgroup gnus-cite nil
  "Citation."
  :prefix "gnus-cite-"
  :link '(custom-manual "(gnus)Article Highlighting")
  :group 'gnus-article)

(defcustom gnus-cited-opened-text-button-line-format "%(%{[-]%}%)\n"
  "Format of opened cited text buttons."
  :group 'gnus-cite
  :type 'string)

(defcustom gnus-cited-closed-text-button-line-format "%(%{[+]%}%)\n"
  "Format of closed cited text buttons."
  :group 'gnus-cite
  :type 'string)

(defcustom gnus-cited-lines-visible nil
  "The number of lines of hidden cited text to remain visible.
Or a pair (cons) of numbers which are the number of lines at the top
and bottom of the text, respectively, to remain visible."
  :group 'gnus-cite
  :type '(choice (const :tag "none" nil)
		 integer
		 (cons :tag "Top and Bottom" integer integer)))

(defcustom gnus-cite-parse-max-size 25000
  "Maximum article size (in bytes) where parsing citations is allowed.
Set it to nil to parse all articles."
  :group 'gnus-cite
  :type '(choice (const :tag "all" nil)
		 integer))

(defcustom gnus-cite-max-prefix 20
  "Maximum possible length for a citation prefix."
  :group 'gnus-cite
  :type 'integer)

(defcustom gnus-supercite-regexp
  (concat "^\\(" message-cite-prefix-regexp "\\)? *"
	  ">>>>> +\"\\([^\"\n]+\\)\" +==")
  "*Regexp matching normal Supercite attribution lines.
The first grouping must match prefixes added by other packages."
  :group 'gnus-cite
  :type 'regexp)

(defcustom gnus-supercite-secondary-regexp "^.*\"\\([^\"\n]+\\)\" +=="
  "Regexp matching mangled Supercite attribution lines.
The first regexp group should match the Supercite attribution."
  :group 'gnus-cite
  :type 'regexp)

(defcustom gnus-cite-minimum-match-count 2
  "Minimum number of identical prefixes before we believe it's a citation."
  :group 'gnus-cite
  :type 'integer)

;; Some Microsoft products put in a citation that extends to the
;; remainder of the message:
;;
;;     -----Original Message-----
;;     From: ...
;;     To: ...
;;     Sent: ...   [date, in non-RFC-2822 format]
;;     Subject: ...
;;
;;     Cited message, with no prefixes
;;
;; The four headers are always the same.  But note they are prone to
;; folding without additional indentation.
;;
;; Others use "----- Original Message -----" instead, and properly quote
;; the body using "> ".  This style is handled without special cases.

(defcustom gnus-cite-attribution-prefix
  "In article\\|in <\\|On \\(Mon\\|Tue\\|Wed\\|Thu\\|Fri\\|Sat\\|Sun\\),\\|----- ?Original Message ?-----"
  "*Regexp matching the beginning of an attribution line."
  :group 'gnus-cite
  :type 'regexp)

(defcustom gnus-cite-attribution-suffix
  "\\(\\(wrote\\|writes\\|said\\|says\\|>\\)\\(:\\|\\.\\.\\.\\)\\|----- ?Original Message ?-----\\)[ \t]*$"
  "*Regexp matching the end of an attribution line.
The text matching the first grouping will be used as a button."
  :group 'gnus-cite
  :type 'regexp)

(defcustom gnus-cite-unsightly-citation-regexp
  "^-----Original Message-----\nFrom: \\(.+\n\\)+\n"
  "Regexp matching Microsoft-type rest-of-message citations."
  :version "22.1"
  :group 'gnus-cite
  :type 'regexp)

(defcustom gnus-cite-ignore-quoted-from t
  "Non-nil means don't regard lines beginning with \">From \" as cited text.
Those lines may have been quoted by MTAs in order not to mix up with
the envelope From line."
  :version "22.1"
  :group 'gnus-cite
  :type 'boolean)

(defface gnus-cite-attribution '((t (:italic t)))
  "Face used for attribution lines."
  :group 'gnus-cite)
;; backward-compatibility alias
(put 'gnus-cite-attribution-face 'face-alias 'gnus-cite-attribution)
(put 'gnus-cite-attribution-face 'obsolete-face "22.1")

(defcustom gnus-cite-attribution-face 'gnus-cite-attribution
  "Face used for attribution lines.
It is merged with the face for the cited text belonging to the attribution."
  :version "22.1"
  :group 'gnus-cite
  :type 'face)

(defface gnus-cite-1 '((((class color)
			 (background dark))
			(:foreground "light blue"))
		       (((class color)
			 (background light))
			(:foreground "MidnightBlue"))
		       (t
			(:italic t)))
  "Citation face."
  :group 'gnus-cite)
;; backward-compatibility alias
(put 'gnus-cite-face-1 'face-alias 'gnus-cite-1)
(put 'gnus-cite-face-1 'obsolete-face "22.1")

(defface gnus-cite-2 '((((class color)
			 (background dark))
			(:foreground "light cyan"))
		       (((class color)
			 (background light))
			(:foreground "firebrick"))
		       (t
			(:italic t)))
  "Citation face."
  :group 'gnus-cite)
;; backward-compatibility alias
(put 'gnus-cite-face-2 'face-alias 'gnus-cite-2)
(put 'gnus-cite-face-2 'obsolete-face "22.1")

(defface gnus-cite-3 '((((class color)
			 (background dark))
			(:foreground "light yellow"))
		       (((class color)
			 (background light))
			(:foreground "dark green"))
		       (t
			(:italic t)))
  "Citation face."
  :group 'gnus-cite)
;; backward-compatibility alias
(put 'gnus-cite-face-3 'face-alias 'gnus-cite-3)
(put 'gnus-cite-face-3 'obsolete-face "22.1")

(defface gnus-cite-4 '((((class color)
			 (background dark))
			(:foreground "light pink"))
		       (((class color)
			 (background light))
			(:foreground "OrangeRed"))
		       (t
			(:italic t)))
  "Citation face."
  :group 'gnus-cite)
;; backward-compatibility alias
(put 'gnus-cite-face-4 'face-alias 'gnus-cite-4)
(put 'gnus-cite-face-4 'obsolete-face "22.1")

(defface gnus-cite-5 '((((class color)
			 (background dark))
			(:foreground "pale green"))
		       (((class color)
			 (background light))
			(:foreground "dark khaki"))
		       (t
			(:italic t)))
  "Citation face."
  :group 'gnus-cite)
;; backward-compatibility alias
(put 'gnus-cite-face-5 'face-alias 'gnus-cite-5)
(put 'gnus-cite-face-5 'obsolete-face "22.1")

(defface gnus-cite-6 '((((class color)
			 (background dark))
			(:foreground "beige"))
		       (((class color)
			 (background light))
			(:foreground "dark violet"))
		       (t
			(:italic t)))
  "Citation face."
  :group 'gnus-cite)
;; backward-compatibility alias
(put 'gnus-cite-face-6 'face-alias 'gnus-cite-6)
(put 'gnus-cite-face-6 'obsolete-face "22.1")

(defface gnus-cite-7 '((((class color)
			 (background dark))
			(:foreground "orange"))
		       (((class color)
			 (background light))
			(:foreground "SteelBlue4"))
		       (t
			(:italic t)))
  "Citation face."
  :group 'gnus-cite)
;; backward-compatibility alias
(put 'gnus-cite-face-7 'face-alias 'gnus-cite-7)
(put 'gnus-cite-face-7 'obsolete-face "22.1")

(defface gnus-cite-8 '((((class color)
			 (background dark))
			(:foreground "magenta"))
		       (((class color)
			 (background light))
			(:foreground "magenta"))
		       (t
			(:italic t)))
  "Citation face."
  :group 'gnus-cite)
;; backward-compatibility alias
(put 'gnus-cite-face-8 'face-alias 'gnus-cite-8)
(put 'gnus-cite-face-8 'obsolete-face "22.1")

(defface gnus-cite-9 '((((class color)
			 (background dark))
			(:foreground "violet"))
		       (((class color)
			 (background light))
			(:foreground "violet"))
		       (t
			(:italic t)))
  "Citation face."
  :group 'gnus-cite)
;; backward-compatibility alias
(put 'gnus-cite-face-9 'face-alias 'gnus-cite-9)
(put 'gnus-cite-face-9 'obsolete-face "22.1")

(defface gnus-cite-10 '((((class color)
			  (background dark))
			 (:foreground "plum1"))
			(((class color)
			  (background light))
			 (:foreground "medium purple"))
			(t
			 (:italic t)))
  "Citation face."
  :group 'gnus-cite)
;; backward-compatibility alias
(put 'gnus-cite-face-10 'face-alias 'gnus-cite-10)
(put 'gnus-cite-face-10 'obsolete-face "22.1")

(defface gnus-cite-11 '((((class color)
			  (background dark))
			 (:foreground "turquoise"))
			(((class color)
			  (background light))
			 (:foreground "turquoise"))
			(t
			 (:italic t)))
  "Citation face."
  :group 'gnus-cite)
;; backward-compatibility alias
(put 'gnus-cite-face-11 'face-alias 'gnus-cite-11)
(put 'gnus-cite-face-11 'obsolete-face "22.1")

(defcustom gnus-cite-face-list
  '(gnus-cite-1 gnus-cite-2 gnus-cite-3 gnus-cite-4 gnus-cite-5 gnus-cite-6
		gnus-cite-7 gnus-cite-8 gnus-cite-9 gnus-cite-10 gnus-cite-11)
  "*List of faces used for highlighting citations.

When there are citations from multiple articles in the same message,
Gnus will try to give each citation from each article its own face.
This should make it easier to see who wrote what."
  :group 'gnus-cite
  :type '(repeat face)
  :set (lambda (symbol value)
	 (prog1
	     (custom-set-default symbol value)
	   (if (boundp 'gnus-message-max-citation-depth)
	       (setq gnus-message-max-citation-depth (length value)))
	   (if (boundp 'gnus-message-citation-keywords)
	       (setq gnus-message-citation-keywords
		     `((gnus-message-search-citation-line
			,@(let ((list nil)
				(count 1))
			    (dolist (face value (nreverse list))
			      (push (list count (list 'quote face) 'prepend t)
				    list)
			      (setq count (1+ count)))))))))))

(defcustom gnus-cite-hide-percentage 50
  "Only hide excess citation if above this percentage of the body."
  :group 'gnus-cite
  :type 'number)

(defcustom gnus-cite-hide-absolute 10
  "Only hide excess citation if above this number of lines in the body."
  :group 'gnus-cite
  :type 'integer)

(defcustom gnus-cite-blank-line-after-header t
  "If non-nil, put a blank line between the citation header and the button."
  :group 'gnus-cite
  :type 'boolean)

;; This has to go here because its default value depends on
;; gnus-cite-face-list.
(defcustom gnus-article-boring-faces (cons 'gnus-signature gnus-cite-face-list)
  "List of faces that are not worth reading.
If an article has more pages below the one you are looking at, but
nothing on those pages is a word of at least three letters that is not
in a boring face, then the pages will be skipped."
  :type '(repeat face)
  :group 'gnus-article-hiding)

;;; Internal Variables:

(defvar gnus-cite-article nil)
(defvar gnus-cite-overlay-list nil)

(defvar gnus-cite-prefix-alist nil)
;; Alist of citation prefixes.
;; The cdr is a list of lines with that prefix.

(defvar gnus-cite-attribution-alist nil)
;; Alist of attribution lines.
;; The car is a line number.
;; The cdr is the prefix for the citation started by that line.

(defvar gnus-cite-loose-prefix-alist nil)
;; Alist of citation prefixes that have no matching attribution.
;; The cdr is a list of lines with that prefix.

(defvar gnus-cite-loose-attribution-alist nil)
;; Alist of attribution lines that have no matching citation.
;; Each member has the form (WROTE IN PREFIX TAG), where
;; WROTE: is the attribution line number
;; IN: is the line number of the previous line if part of the same attribution,
;; PREFIX: Is the citation prefix of the attribution line(s), and
;; TAG: Is a Supercite tag, if any.

(defvar gnus-cited-opened-text-button-line-format-alist
  `((?b (marker-position beg) ?d)
    (?e (marker-position end) ?d)
    (?n (count-lines beg end) ?d)
    (?l (- end beg) ?d)))
(defvar gnus-cited-opened-text-button-line-format-spec nil)
(defvar gnus-cited-closed-text-button-line-format-alist
  gnus-cited-opened-text-button-line-format-alist)
(defvar gnus-cited-closed-text-button-line-format-spec nil)


;;; Commands:

(defun gnus-article-highlight-citation (&optional force same-buffer)
  "Highlight cited text.
Each citation in the article will be highlighted with a different face.
The faces are taken from `gnus-cite-face-list'.
Attribution lines are highlighted with the same face as the
corresponding citation merged with the face `gnus-cite-attribution'.

Text is considered cited if at least `gnus-cite-minimum-match-count'
lines matches `message-cite-prefix-regexp' with the same prefix.

Lines matching `gnus-cite-attribution-suffix' and perhaps
`gnus-cite-attribution-prefix' are considered attribution lines."
  (interactive (list 'force))
  (with-current-buffer (if same-buffer (current-buffer) gnus-article-buffer)
    (gnus-cite-parse-maybe force)
    (let ((buffer-read-only nil)
	  (alist gnus-cite-prefix-alist)
	  (faces gnus-cite-face-list)
	  (inhibit-point-motion-hooks t)
	  face entry prefix skip numbers number face-alist)
      ;; Loop through citation prefixes.
      (while alist
	(setq entry (car alist)
	      alist (cdr alist)
	      prefix (car entry)
	      numbers (cdr entry)
	      face (car faces)
	      faces (or (cdr faces) gnus-cite-face-list)
	      face-alist (cons (cons prefix face) face-alist))
	(while numbers
	  (setq number (car numbers)
		numbers (cdr numbers))
	  (and (not (assq number gnus-cite-attribution-alist))
	       (not (assq number gnus-cite-loose-attribution-alist))
	       (gnus-cite-add-face number prefix face))))
      ;; Loop through attribution lines.
      (setq alist gnus-cite-attribution-alist)
      (while alist
	(setq entry (car alist)
	      alist (cdr alist)
	      number (car entry)
	      prefix (cdr entry)
	      skip (gnus-cite-find-prefix number)
	      face (cdr (assoc prefix face-alist)))
	;; Add attribution button.
	(goto-char (point-min))
	(forward-line (1- number))
	(when (re-search-forward gnus-cite-attribution-suffix
				 (point-at-eol)
				 t)
	  (gnus-article-add-button (match-beginning 1) (match-end 1)
				   'gnus-cite-toggle prefix))
	;; Highlight attribution line.
	(gnus-cite-add-face number skip face)
	(gnus-cite-add-face number skip gnus-cite-attribution-face))
      ;; Loop through attribution lines.
      (setq alist gnus-cite-loose-attribution-alist)
      (while alist
	(setq entry (car alist)
	      alist (cdr alist)
	      number (car entry)
	      skip (gnus-cite-find-prefix number))
	(gnus-cite-add-face number skip gnus-cite-attribution-face)))))

(defun gnus-dissect-cited-text ()
  "Dissect the article buffer looking for cited text."
  (with-current-buffer gnus-article-buffer
    (gnus-cite-parse-maybe nil t)
    (let ((alist gnus-cite-prefix-alist)
	  prefix numbers number marks m)
      ;; Loop through citation prefixes.
      (while alist
	(setq numbers (pop alist)
	      prefix (pop numbers))
	(while numbers
	  (setq number (pop numbers))
	  (goto-char (point-min))
	  (forward-line number)
	  (push (cons (point-marker) "") marks)
	  (while (and numbers
		      (= (1- number) (car numbers)))
	    (setq number (pop numbers)))
	  (goto-char (point-min))
	  (forward-line (1- number))
	  (push (cons (point-marker) prefix) marks)))
      ;; Skip to the beginning of the body.
      (article-goto-body)
      (push (cons (point-marker) "") marks)
      ;; Find the end of the body.
      (goto-char (point-max))
      (gnus-article-search-signature)
      (push (cons (point-marker) "") marks)
      ;; Sort the marks.
      (setq marks (sort marks 'car-less-than-car))
      (let ((omarks marks))
	(setq marks nil)
	(while (cdr omarks)
	  (if (= (caar omarks) (caadr omarks))
	      (progn
		(unless (equal (cdar omarks) "")
		  (push (car omarks) marks))
		(unless (equal (cdadr omarks) "")
		  (push (cadr omarks) marks))
		(unless (and (equal (cdar omarks) "")
			     (equal (cdadr omarks) "")
			     (not (cddr omarks)))
		  (setq omarks (cdr omarks))))
	    (push (car omarks) marks))
	  (setq omarks (cdr omarks)))
	(when (car omarks)
	  (push (car omarks) marks))
	(setq marks (setq m (nreverse marks)))
	(while (cddr m)
	  (if (and (equal (cdadr m) "")
		   (equal (cdar m) (cdaddr m))
		   (goto-char (caadr m))
		   (looking-at "[ \t]*$")
		   (forward-line 1)
		   (= (point) (caaddr m)))
	      (setcdr m (cdddr m))
	    (setq m (cdr m))))
	marks))))

(defun gnus-article-fill-cited-long-lines ()
  (gnus-article-fill-cited-article nil t))

(defun gnus-article-fill-cited-article (&optional width long-lines)
  "Do word wrapping in the current article.
If WIDTH (the numerical prefix), use that text width when
filling.  If LONG-LINES, only fill sections that have lines
longer than the frame width."
  (interactive "P")
  (with-current-buffer gnus-article-buffer
    (let ((buffer-read-only nil)
	  (inhibit-point-motion-hooks t)
	  (marks (gnus-dissect-cited-text))
	  (adaptive-fill-mode nil)
	  (filladapt-mode nil)
	  (fill-column (if width (prefix-numeric-value width) fill-column)))
      (save-restriction
	(while (cdr marks)
	  (narrow-to-region (caar marks) (caadr marks))
	  (let ((adaptive-fill-regexp
		 (concat "^" (regexp-quote (cdar marks)) " *"))
		(fill-prefix
		 (if (string= (cdar marks) "") ""
		   (concat (cdar marks) " ")))
		(do-fill (not long-lines))
		use-hard-newlines)
	    (unless do-fill
	      (setq do-fill (gnus-article-foldable-buffer (cdar marks))))
	    ;; Note: the XEmacs version of `fill-region' inserts a newline
	    ;; unless the region ends with a newline.
	    (when do-fill
	      (if (not long-lines)
		  (fill-region (point-min) (point-max))
		(goto-char (point-min))
		(while (not (eobp))
		  (end-of-line)
		  (when (prog1
			    (> (current-column) (window-width))
			  (forward-line 1))
		    (save-restriction
		      (narrow-to-region (line-beginning-position 0) (point))
		      (fill-region (point-min) (point-max))))))))
	  (set-marker (caar marks) nil)
	  (setq marks (cdr marks)))
	(when marks
	  (set-marker (caar marks) nil))
	;; All this information is now incorrect.
	(setq gnus-cite-prefix-alist nil
	      gnus-cite-attribution-alist nil
	      gnus-cite-loose-prefix-alist nil
	      gnus-cite-loose-attribution-alist nil
	      gnus-cite-article nil)))))

(defun gnus-article-foldable-buffer (prefix)
  (let ((do-fill nil)
	columns)
    (goto-char (point-min))
    (while (not (eobp))
      (unless (> (length prefix) (- (point-max) (point)))
	(forward-char (length prefix)))
      (skip-chars-forward " \t")
      (unless (eolp)
	(let ((elem (assq (current-column) columns)))
	  (unless elem
	    (setq elem (cons (current-column) 0))
	    (push elem columns))
	  (setcdr elem (1+ (cdr elem)))))
      (end-of-line)
      (when (> (current-column) (window-width))
	(setq do-fill t))
      (forward-line 1))
    (and do-fill
	 ;; We know know that there are long lines here, but does this look
	 ;; like code?  Check for ragged edges on the left.
	 (< (length columns) 3))))

(defun gnus-article-hide-citation (&optional arg force)
  "Toggle hiding of all cited text except attribution lines.
See the documentation for `gnus-article-highlight-citation'.
If given a negative prefix, always show; if given a positive prefix,
always hide."
  (interactive (append (gnus-article-hidden-arg) (list 'force)))
  (gnus-set-format 'cited-opened-text-button t)
  (gnus-set-format 'cited-closed-text-button t)
  (with-current-buffer gnus-article-buffer
    (let ((buffer-read-only nil)
          marks
          (inhibit-point-motion-hooks t)
          (props (nconc (list 'article-type 'cite)
                        gnus-hidden-properties))
          (point (point-min))
          found beg end start)
      (while (setq point
                   (text-property-any point (point-max)
                                      'gnus-callback
                                      'gnus-article-toggle-cited-text))
        (setq found t)
        (goto-char point)
        (gnus-article-toggle-cited-text
         (get-text-property point 'gnus-data) arg)
        (forward-line 1)
        (setq point (point)))
      (unless found
        (setq marks (gnus-dissect-cited-text))
        (while marks
          (setq beg nil
                end nil)
          (while (and marks (string= (cdar marks) ""))
            (setq marks (cdr marks)))
          (when marks
            (setq beg (caar marks)))
          (while (and marks (not (string= (cdar marks) "")))
            (setq marks (cdr marks)))
          (when marks
	    (setq end (caar marks)))
          ;; Skip past lines we want to leave visible.
          (when (and beg end gnus-cited-lines-visible)
            (goto-char beg)
            (forward-line (if (consp gnus-cited-lines-visible)
                              (car gnus-cited-lines-visible)
                            gnus-cited-lines-visible))
            (if (>= (point) end)
                (setq beg nil)
              (setq beg (point-marker))
              (when (consp gnus-cited-lines-visible)
                (goto-char end)
                (forward-line (- (cdr gnus-cited-lines-visible)))
                (if (<= (point) beg)
                    (setq beg nil)
		  (setq end (point-marker))))))
          (when (and beg end)
            (gnus-add-wash-type 'cite)
            ;; We use markers for the end-points to facilitate later
            ;; wrapping and mangling of text.
            (setq beg (set-marker (make-marker) beg)
                  end (set-marker (make-marker) end))
            (gnus-add-text-properties-when 'article-type nil beg end props)
            (goto-char beg)
            (when (and gnus-cite-blank-line-after-header
                       (not (save-excursion (search-backward "\n\n" nil t))))
              (insert "\n"))
            (put-text-property
             (setq start (point-marker))
             (progn
	       (gnus-article-add-button
		(point)
		(progn (eval gnus-cited-closed-text-button-line-format-spec)
		       (point))
		`gnus-article-toggle-cited-text
		(list (cons beg end) start))
	       (point))
             'article-type 'annotation)
            (set-marker beg (point))))))))

(defun gnus-article-toggle-cited-text (args &optional arg)
  "Toggle hiding the text in REGION.
ARG can be nil or a number.  Positive means hide, negative
means show, nil means toggle."
  (let* ((region (car args))
	 (beg (car region))
	 (end (cdr region))
	 (start (cadr args))
	 (hidden
	  (text-property-any beg (1- end) 'article-type 'cite))
	 (inhibit-point-motion-hooks t)
	 buffer-read-only)
    (when (or (null arg)
	      (zerop arg)
	      (and (> arg 0) (not hidden))
	      (and (< arg 0) hidden))
      (if hidden
	  (progn
	    ;; Can't remove 'cite from g-a-wash-types here because
	    ;; multiple citations may be hidden -jas
	    (gnus-remove-text-properties-when
	     'article-type 'cite beg end
	     (cons 'article-type (cons 'cite
				       gnus-hidden-properties))))
	(gnus-add-wash-type 'cite)
	(gnus-add-text-properties-when
	 'article-type nil beg end
	 (cons 'article-type (cons 'cite
				   gnus-hidden-properties))))
      (let ((gnus-article-mime-handle-alist-1 gnus-article-mime-handle-alist))
	(gnus-set-mode-line 'article))
      (save-excursion
	(goto-char start)
	(gnus-delete-line)
	(put-text-property
	 (point)
	 (progn
	   (gnus-article-add-button
	    (point)
	    (progn (eval
		    (if hidden
			gnus-cited-opened-text-button-line-format-spec
		      gnus-cited-closed-text-button-line-format-spec))
		   (point))
	    `gnus-article-toggle-cited-text
	    args)
	   (point))
	 'article-type 'annotation)))))

(defun gnus-article-hide-citation-maybe (&optional arg force)
  "Toggle hiding of cited text that has an attribution line.
If given a negative prefix, always show; if given a positive prefix,
always hide.
This will do nothing unless at least `gnus-cite-hide-percentage'
percent and at least `gnus-cite-hide-absolute' lines of the body is
cited text with attributions.  When called interactively, these two
variables are ignored.
See also the documentation for `gnus-article-highlight-citation'."
  (interactive (append (gnus-article-hidden-arg) '(force)))
  (with-current-buffer gnus-article-buffer
    (gnus-delete-wash-type 'cite)
    (unless (gnus-article-check-hidden-text 'cite arg)
      (save-excursion
	(gnus-cite-parse-maybe force)
	(article-goto-body)
	(let ((start (point))
	      (atts gnus-cite-attribution-alist)
	      (buffer-read-only nil)
	      (inhibit-point-motion-hooks t)
	      (hidden 0)
	      total)
	  (goto-char (point-max))
	  (gnus-article-search-signature)
	  (setq total (count-lines start (point)))
	  (while atts
	    (setq hidden (+ hidden (length
				    (cdr (assoc (cdar atts)
						gnus-cite-prefix-alist))))
		  atts (cdr atts)))
	  (when (or force
		    (and (> (* 100 hidden) (* gnus-cite-hide-percentage total))
			 (> hidden gnus-cite-hide-absolute)))
	    (gnus-article-hide-citation)))))))

(defun gnus-article-hide-citation-in-followups ()
  "Hide cited text in non-root articles."
  (interactive)
  (with-current-buffer gnus-article-buffer
    (let ((article (cdr gnus-article-current)))
      (unless (with-current-buffer gnus-summary-buffer
		(gnus-article-displayed-root-p article))
	(gnus-article-hide-citation)))))

;;; Internal functions:

(defun gnus-cite-parse-maybe (&optional force no-overlay)
  "Always parse the buffer."
  (gnus-cite-localize)
  ;;Reset parser information.
  (setq gnus-cite-prefix-alist nil
	gnus-cite-attribution-alist nil
	gnus-cite-loose-prefix-alist nil
	gnus-cite-loose-attribution-alist nil)
  (unless no-overlay
    (gnus-cite-delete-overlays))
  ;; Parse if not too large.
  (if (and gnus-cite-parse-max-size
	   (> (buffer-size) gnus-cite-parse-max-size))
      ()
    (setq gnus-cite-article (cons (car gnus-article-current)
				  (cdr gnus-article-current)))
    (gnus-cite-parse-wrapper)))

(defun gnus-cite-delete-overlays ()
  (dolist (overlay gnus-cite-overlay-list)
    (ignore-errors
      (when (or (not (gnus-overlay-end overlay))
		(and (>= (gnus-overlay-end overlay) (point-min))
		     (<= (gnus-overlay-end overlay) (point-max))))
	(setq gnus-cite-overlay-list (delete overlay gnus-cite-overlay-list))
	(ignore-errors
	  (gnus-delete-overlay overlay))))))

(defun gnus-cite-parse-wrapper ()
  ;; Wrap chopped gnus-cite-parse.
  (article-goto-body)
  (let ((inhibit-point-motion-hooks t))
    (save-excursion
      (gnus-cite-parse-attributions))
    (save-excursion
      (gnus-cite-parse))
    (save-excursion
      (gnus-cite-connect-attributions))))

(defun gnus-cite-parse ()
  ;; Parse and connect citation prefixes and attribution lines.

  ;; Parse current buffer searching for citation prefixes.
  (let ((line (1+ (count-lines (point-min) (point))))
	(case-fold-search t)
	(max (save-excursion
	       (goto-char (point-max))
	       (gnus-article-search-signature)
	       (point)))
	(prefix-regexp (concat "^\\(" message-cite-prefix-regexp "\\)"))
	alist entry start begin end numbers prefix guess-limit)
    ;; Get all potential prefixes in `alist'.
    (while (< (point) max)
      ;; Each line.
      (setq begin (point)
	    guess-limit (progn (skip-chars-forward "^> \t\r\n") (point))
	    end (point-at-bol 2)
	    start end)
      (goto-char begin)
      ;; Ignore standard Supercite attribution prefix.
      (when (and (< guess-limit (+ begin gnus-cite-max-prefix))
		 (looking-at gnus-supercite-regexp))
	(if (match-end 1)
	    (setq end (1+ (match-end 1)))
	  (setq end (1+ begin))))
      ;; Ignore very long prefixes.
      (when (> end (+ begin gnus-cite-max-prefix))
	(setq end (+ begin gnus-cite-max-prefix)))
      ;; Ignore quoted envelope From_.
      (when (and gnus-cite-ignore-quoted-from
		 (prog2
		     (setq case-fold-search nil)
		     (looking-at ">From ")
		   (setq case-fold-search t)))
	(setq end (1+ begin)))
      (while (re-search-forward prefix-regexp (1- end) t)
	;; Each prefix.
	(setq end (match-end 0)
	      prefix (buffer-substring begin end))
	(set-text-properties 0 (length prefix) nil prefix)
	(setq entry (assoc prefix alist))
	(if entry
	    (setcdr entry (cons line (cdr entry)))
	  (push (list prefix line) alist))
	(goto-char begin))
      (goto-char start)
      (setq line (1+ line)))
    ;; Horrible special case for some Microsoft mailers.
    (goto-char (point-min))
    (setq start t begin nil entry nil)
    (while start
      ;; Assume this search ends up at the beginning of a line.
      (if (re-search-forward gnus-cite-unsightly-citation-regexp max t)
	  (progn
	    (when (number-or-marker-p start)
	      (setq begin (count-lines (point-min) start)
		    end (count-lines (point-min) (match-beginning 0))))
	    (setq start (match-end 0)))
	(when (number-or-marker-p start)
	  (setq begin (count-lines (point-min) start)
		end (count-lines (point-min) max)))
	(setq start nil))
      (when begin
	(while (< begin end)
	  ;; Need to do 1+ because we're in the bol.
	  (push (setq begin (1+ begin)) entry))))
    (when entry
      (push (cons "" entry) alist))
    ;; We got all the potential prefixes.  Now create
    ;; `gnus-cite-prefix-alist' containing the oldest prefix for each
    ;; line that appears at least `gnus-cite-minimum-match-count'
    ;; times.  First sort them by length.  Longer is older.
    (setq alist (sort alist (lambda (a b)
			      (> (length (car a)) (length (car b))))))
    (while alist
      (setq entry (car alist)
	    prefix (car entry)
	    numbers (cdr entry)
	    alist (cdr alist))
      (cond ((null numbers)
	     ;; No lines with this prefix that wasn't also part of
	     ;; a longer prefix.
	     )
	    ((< (length numbers) gnus-cite-minimum-match-count)
	     ;; Too few lines with this prefix.  We keep it a bit
	     ;; longer in case it is an exact match for an attribution
	     ;; line, but we don't remove the line from other
	     ;; prefixes.
	     (push entry gnus-cite-prefix-alist))
	    (t
	     (push entry
		   gnus-cite-prefix-alist)
	     ;; Remove articles from other prefixes.
	     (let ((loop alist)
		   current)
	       (while loop
		 (setq current (car loop)
		       loop (cdr loop))
		 (setcdr current
			 (gnus-set-difference (cdr current) numbers)))))))))

(defun gnus-cite-parse-attributions ()
  (let (al-alist)
    ;; Parse attributions
    (while (re-search-forward gnus-cite-attribution-suffix (point-max) t)
      (let* ((start (match-beginning 0))
	     (end (match-end 0))
	     (wrote (count-lines (point-min) end))
	     (prefix (gnus-cite-find-prefix wrote))
	     ;; Check previous line for an attribution leader.
	     (tag (progn
		    (beginning-of-line 1)
		    (when (looking-at gnus-supercite-secondary-regexp)
		      (buffer-substring (match-beginning 1)
					(match-end 1)))))
	     (in (progn
		   (goto-char start)
		   (and (re-search-backward gnus-cite-attribution-prefix
					    (save-excursion
					      (beginning-of-line 0)
					      (point))
					    t)
			(not (re-search-forward gnus-cite-attribution-suffix
						start t))
			(count-lines (point-min) (1+ (point)))))))
	(when (eq wrote in)
	  (setq in nil))
	(goto-char end)
	;; don't add duplicates
	(let ((al (buffer-substring (save-excursion (beginning-of-line 0)
						    (1+ (point)))
				    end)))
	  (when (not (assoc al al-alist))
	    (push (list wrote in prefix tag)
		  gnus-cite-loose-attribution-alist)
	    (push (cons al t) al-alist)))))))

(defun gnus-cite-connect-attributions ()
  ;; Connect attributions to citations

  ;; No citations have been connected to attribution lines yet.
  (setq gnus-cite-loose-prefix-alist (append gnus-cite-prefix-alist nil))

  ;; Parse current buffer searching for attribution lines.
  ;; Find exact supercite citations.
  (gnus-cite-match-attributions 'small nil
				(lambda (prefix tag)
				  (when tag
				    (concat "\\`"
					    (regexp-quote prefix) "[ \t]*"
					    (regexp-quote tag) ">"))))
  ;; Find loose supercite citations after attributions.
  (gnus-cite-match-attributions 'small t
				(lambda (prefix tag)
				  (when tag
				    (concat "\\<"
					    (regexp-quote tag)
					    "\\>"))))
  ;; Find loose supercite citations anywhere.
  (gnus-cite-match-attributions 'small nil
				(lambda (prefix tag)
				  (when tag
				    (concat "\\<"
					    (regexp-quote tag)
					    "\\>"))))
  ;; Find nested citations after attributions.
  (gnus-cite-match-attributions 'small-if-unique t
				(lambda (prefix tag)
				  (concat "\\`" (regexp-quote prefix) ".+")))
  ;; Find nested citations anywhere.
  (gnus-cite-match-attributions 'small nil
				(lambda (prefix tag)
				  (concat "\\`" (regexp-quote prefix) ".+")))
  ;; Remove loose prefixes with too few lines.
  (let ((alist gnus-cite-loose-prefix-alist)
	entry)
    (while alist
      (setq entry (car alist)
	    alist (cdr alist))
      (when (< (length (cdr entry)) gnus-cite-minimum-match-count)
	(setq gnus-cite-prefix-alist
	      (delq entry gnus-cite-prefix-alist)
	      gnus-cite-loose-prefix-alist
	      (delq entry gnus-cite-loose-prefix-alist)))))
  ;; Find flat attributions.
  (gnus-cite-match-attributions 'first t nil)
  ;; Find any attributions (are we getting desperate yet?).
  (gnus-cite-match-attributions 'first nil nil))

(defun gnus-cite-match-attributions (sort after fun)
  ;; Match all loose attributions and citations (SORT AFTER FUN) .
  ;;
  ;; If SORT is `small', the citation with the shortest prefix will be
  ;; used, if it is `first' the first prefix will be used, if it is
  ;; `small-if-unique' the shortest prefix will be used if the
  ;; attribution line does not share its own prefix with other
  ;; loose attribution lines, otherwise the first prefix will be used.
  ;;
  ;; If AFTER is non-nil, only citations after the attribution line
  ;; will be considered.
  ;;
  ;; If FUN is non-nil, it will be called with the arguments (WROTE
  ;; PREFIX TAG) and expected to return a regular expression.  Only
  ;; citations whose prefix matches the regular expression will be
  ;; considered.
  ;;
  ;; WROTE is the attribution line number.
  ;; PREFIX is the attribution line prefix.
  ;; TAG is the Supercite tag on the attribution line.
  (let ((atts gnus-cite-loose-attribution-alist)
	(case-fold-search t)
	att wrote in prefix tag regexp limit smallest best size)
    (while atts
      (setq att (car atts)
	    atts (cdr atts)
	    wrote (nth 0 att)
	    in (nth 1 att)
	    prefix (nth 2 att)
	    tag (nth 3 att)
	    regexp (if fun (funcall fun prefix tag) "")
	    size (cond ((eq sort 'small) t)
		       ((eq sort 'first) nil)
		       (t (< (length (gnus-cite-find-loose prefix)) 2)))
	    limit (if after wrote -1)
	    smallest 1000000
	    best nil)
      (let ((cites gnus-cite-loose-prefix-alist)
	    cite candidate numbers first compare)
	(while cites
	  (setq cite (car cites)
		cites (cdr cites)
		candidate (car cite)
		numbers (cdr cite)
		first (apply 'min numbers)
		compare (if size (length candidate) first))
	  (and (> first limit)
	       regexp
	       (string-match regexp candidate)
	       (< compare smallest)
	       (setq best cite
		     smallest compare))))
      (if (null best)
	  ()
	(setq gnus-cite-loose-attribution-alist
	      (delq att gnus-cite-loose-attribution-alist))
	(push (cons wrote (car best)) gnus-cite-attribution-alist)
	(when in
	  (push (cons in (car best)) gnus-cite-attribution-alist))
	(when (memq best gnus-cite-loose-prefix-alist)
	  (let ((loop gnus-cite-prefix-alist)
		(numbers (cdr best))
		current)
	    (setq gnus-cite-loose-prefix-alist
		  (delq best gnus-cite-loose-prefix-alist))
	    (while loop
	      (setq current (car loop)
		    loop (cdr loop))
	      (if (eq current best)
		  ()
		(setcdr current (gnus-set-difference (cdr current) numbers))
		(when (null (cdr current))
		  (setq gnus-cite-loose-prefix-alist
			(delq current gnus-cite-loose-prefix-alist)
			atts (delq current atts)))))))))))

(defun gnus-cite-find-loose (prefix)
  ;; Return a list of loose attribution lines prefixed by PREFIX.
  (let* ((atts gnus-cite-loose-attribution-alist)
	 att line lines)
    (while atts
      (setq att (car atts)
	    line (car att)
	    atts (cdr atts))
      (when (string-equal (gnus-cite-find-prefix line) prefix)
	(push line lines)))
    lines))

(defun gnus-cite-add-face (number prefix face)
  ;; At line NUMBER, ignore PREFIX and add FACE to the rest of the line.
  (when face
    (let ((inhibit-point-motion-hooks t)
	  from to overlay)
      (goto-char (point-min))
      (when (zerop (forward-line (1- number)))
	(forward-char (length prefix))
	(skip-chars-forward " \t")
	(setq from (point))
	(end-of-line 1)
	(skip-chars-backward " \t")
	(setq to (point))
	(when (< from to)
	  (push (setq overlay (gnus-make-overlay from to nil t))
		gnus-cite-overlay-list)
	  (gnus-overlay-put overlay 'evaporate t)
	  (gnus-overlay-put overlay 'face face))))))

(defun gnus-cite-toggle (prefix)
  (with-current-buffer gnus-article-buffer
    (gnus-cite-parse-maybe nil t)
    (let ((buffer-read-only nil)
	  (numbers (cdr (assoc prefix gnus-cite-prefix-alist)))
	  (inhibit-point-motion-hooks t)
	  number)
      (while numbers
	(setq number (car numbers)
	      numbers (cdr numbers))
	(goto-char (point-min))
	(forward-line (1- number))
	(cond ((get-text-property (point) 'invisible)
	       ;; Can't remove 'cite from g-a-wash-types here because
	       ;; multiple citations may be hidden -jas
	       (remove-text-properties (point) (progn (forward-line 1) (point))
				       gnus-hidden-properties))
	      ((assq number gnus-cite-attribution-alist))
	      (t
	       (gnus-add-wash-type 'cite)
	       (gnus-add-text-properties
		(point) (progn (forward-line 1) (point))
		(nconc (list 'article-type 'cite)
		       gnus-hidden-properties))))
	(let ((gnus-article-mime-handle-alist-1
	       gnus-article-mime-handle-alist))
	  (gnus-set-mode-line 'article))))))

(defun gnus-cite-find-prefix (line)
  ;; Return citation prefix for LINE.
  (let ((alist gnus-cite-prefix-alist)
	(prefix "")
	entry)
    (while alist
      (setq entry (car alist)
	    alist (cdr alist))
      (when (memq line (cdr entry))
	(setq prefix (car entry))))
    prefix))

(defun gnus-cite-localize ()
  "Make the citation variables local to the article buffer."
  (let ((vars '(gnus-cite-article
		gnus-cite-overlay-list gnus-cite-prefix-alist
		gnus-cite-attribution-alist gnus-cite-loose-prefix-alist
		gnus-cite-loose-attribution-alist)))
    (while vars
      (make-local-variable (pop vars)))))

;; Highlighting of different citation levels in message-mode.
;; - message-cite-prefix will be overridden if this is enabled.

(defvar gnus-message-max-citation-depth
  (length gnus-cite-face-list)
  "Maximum supported level of citation.")

(defvar gnus-message-cite-prefix-regexp
  (concat "^\\(?:" message-cite-prefix-regexp "\\)"))

(defun gnus-message-search-citation-line (limit)
  "Search for a cited line and set match data accordingly.
Returns nil if there is no such line before LIMIT, t otherwise."
  (when (re-search-forward gnus-message-cite-prefix-regexp limit t)
    (let ((cdepth (min (length (apply 'concat
				      (split-string
				       (match-string-no-properties 0)
				       "[ \t [:alnum:]]+")))
		       gnus-message-max-citation-depth))
	  (mlist (make-list (* (1+ gnus-message-max-citation-depth) 2) nil))
	  (start (point-at-bol))
	  (end (point-at-eol)))
      (setcar mlist start)
      (setcar (cdr mlist) end)
      (setcar (nthcdr (* cdepth 2) mlist) start)
      (setcar (nthcdr (1+ (* cdepth 2)) mlist) end)
      (set-match-data mlist))
    t))

(defvar gnus-message-citation-keywords
  ;; eval-when-compile ;; This breaks in XEmacs
  `((gnus-message-search-citation-line
     ,@(let ((list nil)
	     (count 1))
	 ;; (require 'gnus-cite)
	 (dolist (face gnus-cite-face-list (nreverse list))
	   (push (list count (list 'quote face) 'prepend t) list)
	   (setq count (1+ count)))))) ;;
  "Keywords for highlighting different levels of message citations.")

(defvar font-lock-defaults-computed)
(defvar font-lock-keywords)
(defvar font-lock-set-defaults)

(eval-and-compile
  (unless (featurep 'xemacs)
    (autoload 'font-lock-set-defaults "font-lock")))

(define-minor-mode gnus-message-citation-mode
  "Minor mode providing more font-lock support for nested citations.
When enabled, it automatically turns on `font-lock-mode'."
  nil ;; init-value
  "" ;; lighter
  nil ;; keymap
  (when (eq major-mode 'message-mode)   ;FIXME: Use derived-mode-p.
    ;; FIXME: Use font-lock-add-keywords!
    (let ((defaults (car (if (featurep 'xemacs)
			     (get 'message-mode 'font-lock-defaults)
			   font-lock-defaults)))
	  default keywords)
      (while defaults
	(setq default (if (consp defaults)
			  (pop defaults)
			(prog1
			    defaults
			  (setq defaults nil))))
	(if gnus-message-citation-mode
	    ;; `gnus-message-citation-keywords' should be the last
	    ;; elements of the keywords because the others are unlikely
	    ;; to have the OVERRIDE flags -- XEmacs applies a keyword
	    ;; having no OVERRIDE flag to matched text even if it has
	    ;; already other faces, while Emacs doesn't.
	    (set (make-local-variable default)
		 (append (default-value default)
			 gnus-message-citation-keywords))
	  (kill-local-variable default))))
    ;; Force `font-lock-set-defaults' to update `font-lock-keywords'.
    (if (featurep 'xemacs)
	(progn
	  (require 'font-lock)
	  (setq font-lock-defaults-computed nil
		font-lock-keywords nil))
      (setq font-lock-set-defaults nil))
    (font-lock-set-defaults)
    (cond (font-lock-mode
           (if (fboundp 'font-lock-flush)
               (font-lock-flush)
             (font-lock-fontify-buffer)))
	  (gnus-message-citation-mode
	   (font-lock-mode 1)))))

(defun turn-on-gnus-message-citation-mode ()
  "Turn on `gnus-message-citation-mode'."
  (gnus-message-citation-mode 1))
(defun turn-off-gnus-message-citation-mode ()
  "Turn off `gnus-message-citation-mode'."
  (gnus-message-citation-mode -1))

(gnus-ems-redefine)

(provide 'gnus-cite)

;; Local Variables:
;; coding: utf-8
;; End:

;;; gnus-cite.el ends here