Source

xemacs-21.4 / lisp / help.el

   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
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
;;; help.el --- help commands for XEmacs.

;; Copyright (C) 1985, 1986, 1992-4, 1997 Free Software Foundation, Inc.

;; Maintainer: FSF
;; Keywords: help, internal, dumped

;; This file is part of XEmacs.

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

;; XEmacs 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 XEmacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Synched up with: FSF 19.30.

;;; Commentary:

;; This file is dumped with XEmacs.

;; This code implements XEmacs's on-line help system, the one invoked by
;;`M-x help-for-help'.

;; 06/11/1997 -- Converted to use char-after instead of broken
;;  following-char. -slb

;;; Code:

;; Get the macro make-help-screen when this is compiled,
;; or run interpreted, but not when the compiled code is loaded.
(eval-when-compile (require 'help-macro))

(defgroup help nil
  "Support for on-line help systems."
  :group 'emacs)

(defgroup help-appearance nil
  "Appearance of help buffers."
  :group 'help)

(defvar help-map (let ((map (make-sparse-keymap)))
                   (set-keymap-name map 'help-map)
                   (set-keymap-prompt
                     map (purecopy (gettext "(Type ? for further options)")))
                   map)
  "Keymap for characters following the Help key.")

;; global-map definitions moved to keydefs.el
(fset 'help-command help-map)

(define-key help-map (vector help-char) 'help-for-help)
(define-key help-map "?" 'help-for-help)
(define-key help-map 'help 'help-for-help)
(define-key help-map '(f1) 'help-for-help)

(define-key help-map "\C-l" 'describe-copying) ; on \C-c in FSFmacs
(define-key help-map "\C-d" 'describe-distribution)
(define-key help-map "\C-w" 'describe-no-warranty)
(define-key help-map "a" 'hyper-apropos) ; 'command-apropos in FSFmacs
(define-key help-map "A" 'command-apropos)

(define-key help-map "b" 'describe-bindings)
(define-key help-map "B" 'describe-beta)
(define-key help-map "\C-p" 'describe-pointer)

(define-key help-map "C" 'customize)
(define-key help-map "c" 'describe-key-briefly)
(define-key help-map "k" 'describe-key)

(define-key help-map "d" 'describe-function)
(define-key help-map "e" 'describe-last-error)
(define-key help-map "f" 'describe-function)

(define-key help-map "F" 'xemacs-local-faq)

(define-key help-map "i" 'info)
(define-key help-map '(control i) 'Info-query)
;; FSFmacs has Info-goto-emacs-command-node on C-f, no binding
;; for Info-elisp-ref
(define-key help-map '(control c) 'Info-goto-emacs-command-node)
(define-key help-map '(control k) 'Info-goto-emacs-key-command-node)
(define-key help-map '(control f) 'Info-elisp-ref)

(define-key help-map "l" 'view-lossage)

(define-key help-map "m" 'describe-mode)

(define-key help-map "\C-n" 'view-emacs-news)
(define-key help-map "n" 'view-emacs-news)

(define-key help-map "p" 'finder-by-keyword)

;; Do this right with an autoload cookie in finder.el.
;;(autoload 'finder-by-keyword "finder"
;;  "Find packages matching a given keyword." t)

(define-key help-map "s" 'describe-syntax)

(define-key help-map "t" 'help-with-tutorial)

(define-key help-map "w" 'where-is)

(define-key help-map "v" 'describe-variable)

(if (fboundp 'view-last-error)
    (define-key help-map "e" 'view-last-error))


(define-key help-map "q" 'help-quit)

;#### This stuff was an attempt to have font locking and hyperlinks in the
;help buffer, but it doesn't really work.  Some of this stuff comes from
;FSF Emacs; but the FSF Emacs implementation is rather broken, as usual.
;What needs to happen is this:
;
; -- we probably need a "hyperlink mode" from which help-mode is derived.
; -- this means we probably need multiple inheritance of modes!
;    Thankfully this is not hard to implement; we already have the
;    ability for a keymap to have multiple parents.  However, we'd
;    have to define any multiply-inherited-from modes using a standard
;    `define-mode' construction instead of manually doing it, because
;    we don't want each guy calling `kill-all-local-variables' and
;    messing up the previous one.
; -- we need to scan the buffer ourselves (not from font-lock, because
;    the user might not have font-lock enabled) and highlight only
;    those words that are *documented* functions and variables (and
;    probably excluding words without dashes in them unless enclosed
;    in quotes, so that common words like "list" and "point" don't
;    become hyperlinks.
; -- we should *not* use font-lock keywords like below.  Instead we
;    should add the font-lock stuff ourselves during the scanning phase,
;    if font-lock is enabled in this buffer.

;(defun help-follow-reference (event extent user-data)
;  (let ((symbol (intern-soft (extent-string extent))))
;    (cond ((and symbol (fboundp symbol))
;	   (describe-function symbol))
;	  ((and symbol (boundp symbol))
;	   (describe-variable symbol))
;	  (t nil))))

;(defvar help-font-lock-keywords
;  (let ((name-char "[-+a-zA-Z0-9_*]") (sym-char "[-+a-zA-Z0-9_:*]"))
;    (list
;     ;;
;     ;; The symbol itself.
;     (list (concat "\\`\\(" name-char "+\\)\\(:\\)?")
;	   '(1 (if (match-beginning 2)
;		   'font-lock-function-name-face
;		 'font-lock-variable-name-face)
;	       nil t))
;     ;;
;     ;; Words inside `' which tend to be symbol names.
;     (list (concat "`\\(" sym-char sym-char "+\\)'")
;	   1 '(prog1
;		  'font-lock-reference-face
;		(add-list-mode-item (match-beginning 1)
;			       (match-end 1)
;			       nil
;			       'help-follow-reference))
;	   t)
;     ;;
;     ;; CLisp `:' keywords as references.
;     (list (concat "\\<:" sym-char "+\\>") 0 'font-lock-reference-face t)))
;  "Default expressions to highlight in Help mode.")

;(put 'help-mode 'font-lock-defaults '(help-font-lock-keywords))

(define-derived-mode help-mode view-major-mode "Help"
  "Major mode for viewing help text.
Entry to this mode runs the normal hook `help-mode-hook'.
Commands:
\\{help-mode-map}"
  )

(define-key help-mode-map "q" 'help-mode-quit)
(define-key help-mode-map "Q" 'help-mode-bury)
(define-key help-mode-map "f" 'find-function-at-point)
(define-key help-mode-map "d" 'describe-function-at-point)
(define-key help-mode-map "v" 'describe-variable-at-point)
(define-key help-mode-map "i" 'Info-elisp-ref)
(define-key help-mode-map "c" 'customize-variable)
(define-key help-mode-map [tab] 'help-next-symbol)
(define-key help-mode-map [(shift tab)] 'help-prev-symbol)
(define-key help-mode-map "n" 'help-next-section)
(define-key help-mode-map "p" 'help-prev-section)

(defun describe-function-at-point ()
  "Describe directly the function at point in the other window."
  (interactive)
  (let ((symb (function-at-point)))
    (when symb
      (describe-function symb))))

(defun describe-variable-at-point ()
  "Describe directly the variable at point in the other window."
  (interactive)
  (let ((symb (variable-at-point)))
    (when symb
      (describe-variable symb))))

(defun help-next-symbol ()
  "Move point to the next quoted symbol."
  (interactive)
  (search-forward "`" nil t))

(defun help-prev-symbol ()
  "Move point to the previous quoted symbol."
  (interactive)
  (search-backward "'" nil t))

(defun help-next-section ()
  "Move point to the next quoted symbol."
  (interactive)
  (search-forward-regexp "^\\w+:" nil t))

(defun help-prev-section ()
  "Move point to the previous quoted symbol."
  (interactive)
  (search-backward-regexp "^\\w+:" nil t))

(defun help-mode-bury ()
  "Bury the help buffer, possibly restoring the previous window configuration."
  (interactive)
  (help-mode-quit t))

(defun help-mode-quit (&optional bury)
  "Exit from help mode, possibly restoring the previous window configuration.
If the optional argument BURY is non-nil, the help buffer is buried,
otherwise it is killed."
  (interactive)
  (let ((buf (current-buffer)))
    (cond ((frame-property (selected-frame) 'help-window-config)
	   (set-window-configuration
	    (frame-property (selected-frame) 'help-window-config))
	   (set-frame-property  (selected-frame) 'help-window-config nil))
	  ((not (one-window-p))
	   (delete-window)))
    (if bury
	(bury-buffer buf)
      (kill-buffer buf))))

(defun help-quit ()
  (interactive)
  nil)

;; This is a grody hack of the same genotype as `advertised-undo'; if the
;; bindings of Backspace and C-h are the same, we want the menubar to claim
;; that `info' in invoked with `C-h i', not `BS i'.

(defun deprecated-help-command ()
  (interactive)
  (if (eq 'help-command (key-binding "\C-h"))
      (setq unread-command-event (character-to-event ?\C-h))
    (help-for-help)))

;;(define-key global-map 'backspace 'deprecated-help-command)

;; This function has been moved to help-nomule.el and mule-help.el.
;; TUTORIAL arg is XEmacs addition
;(defun help-with-tutorial (&optional tutorial)
;  "Select the XEmacs learn-by-doing tutorial.
;Optional arg TUTORIAL specifies the tutorial file; default is \"TUTORIAL\"."
;  (interactive)
;  (if (null tutorial)
;      (setq tutorial "TUTORIAL"))
;  (let ((file (expand-file-name (concat "~/" tutorial))))
;    (delete-other-windows)
;    (if (get-file-buffer file)
;	(switch-to-buffer (get-file-buffer file))
;      (switch-to-buffer (create-file-buffer file))
;      (setq buffer-file-name file)
;      (setq default-directory (expand-file-name "~/"))
;      (setq buffer-auto-save-file-name nil)
;      (insert-file-contents (expand-file-name tutorial data-directory))
;      (goto-char (point-min))
;      (search-forward "\n<<")
;      (delete-region (point-at-bol) (point-at-eol))
;      (let ((n (- (window-height (selected-window))
;		  (count-lines (point-min) (point))
;		  6)))
;	(if (< n 12)
;	    (newline n)
;	  ;; Some people get confused by the large gap.
;	  (newline (/ n 2))
;	  (insert "[Middle of page left blank for didactic purposes.  "
;		  "Text continues below]")
;	  (newline (- n (/ n 2)))))
;      (goto-char (point-min))
;      (set-buffer-modified-p nil))))

;; used by describe-key, describe-key-briefly, insert-key-binding, etc.

(defun key-or-menu-binding (key &optional menu-flag)
  "Return the command invoked by KEY.
Like `key-binding', but handles menu events and toolbar presses correctly.
KEY is any value returned by `next-command-event'.
MENU-FLAG is a symbol that should be set to T if KEY is a menu event,
 or NIL otherwise"
  (let (defn)
    (and menu-flag (set menu-flag nil))
    ;; If the key typed was really a menu selection, grab the form out
    ;; of the event object and intuit the function that would be called,
    ;; and describe that instead.
    (if (and (vectorp key) (= 1 (length key))
	     (or (misc-user-event-p (aref key 0))
		 (eq (car-safe (aref key 0)) 'menu-selection)))
	(let ((event (aref key 0)))
	  (setq defn (if (eventp event)
			 (list (event-function event) (event-object event))
		       (cdr event)))
	  (and menu-flag (set menu-flag t))
	  (when (eq (car defn) 'eval)
	    (setq defn (car (cdr defn))))
	  (when (eq (car-safe defn) 'call-interactively)
	    (setq defn (car (cdr defn))))
	  (when (and (consp defn) (null (cdr defn)))
	    (setq defn (car defn))))
      ;; else
      (setq defn (key-binding key)))
    ;; kludge: if a toolbar button was pressed on, try to find the
    ;; binding of the toolbar button.
    (if (and (eq defn 'press-toolbar-button)
	     (vectorp key)
	     (button-press-event-p (aref key (1- (length key)))))
	;; wait for the button release.  We're on shaky ground here ...
	(let ((event (next-command-event))
	      button)
	  (if (and (button-release-event-p event)
		   (event-over-toolbar-p event)
		   (eq 'release-and-activate-toolbar-button
		       (key-binding (vector event)))
		   (setq button (event-toolbar-button event)))
	      (toolbar-button-callback button)
	    ;; if anything went wrong, try returning the binding of
	    ;; the button-up event, of the original binding
	    (or (key-or-menu-binding (vector event))
		defn)))
      ;; no toolbar kludge
      defn)
    ))

(defun describe-key-briefly (key &optional insert)
  "Print the name of the function KEY invokes.  KEY is a string.
If INSERT (the prefix arg) is non-nil, insert the message in the buffer."
  (interactive "kDescribe key briefly: \nP")
  (let ((standard-output (if insert (current-buffer) t))
	defn menup)
    (setq defn (key-or-menu-binding key 'menup))
    (if (or (null defn) (integerp defn))
        (princ (format "%s is undefined" (key-description key)))
      ;; If it's a keyboard macro which trivially invokes another command,
      ;; document that instead.
      (if (or (stringp defn) (vectorp defn))
	  (setq defn (or (key-binding defn)
			 defn)))
      (let ((last-event (and (vectorp key)
			     (aref key (1- (length key))))))
	(princ (format (cond (insert
			      "%s (%s)")
			     ((or (button-press-event-p last-event)
				  (button-release-event-p last-event))
			      (gettext "%s at that spot runs the command %s"))
			     (t
			      (gettext "%s runs the command %s")))
		       ;; This used to say 'This menu item' but it
		       ;; could also be a scrollbar event.  We can't
		       ;; distinguish at the moment.
		       (if menup
			   (if insert "item" "This item")
			 (key-description key))
		       (if (symbolp defn) defn (prin1-to-string defn))))))))

;; #### this is a horrible piece of shit function that should
;; not exist.  In FSF 19.30 this function has gotten three times
;; as long and has tons and tons of dumb shit checking
;; special-display-buffer-names and such crap.  I absolutely
;; refuse to insert that Ebolification here.  I wanted to delete
;; this function entirely but Mly bitched.
;;
;; If your user-land code calls this function, rewrite it to
;; call with-displaying-help-buffer.

(defun print-help-return-message (&optional function)
  "Display or return message saying how to restore windows after help command.
Computes a message and applies the optional argument FUNCTION to it.
If FUNCTION is nil, applies `message' to it, thus printing it."
  (and (not (get-buffer-window standard-output))
       (funcall
	(or function 'message)
	(concat
         (substitute-command-keys
          (if (one-window-p t)
              (if pop-up-windows
                  (gettext "Type \\[delete-other-windows] to remove help window.")
                (gettext "Type \\[switch-to-buffer] RET to remove help window."))
   (gettext "Type \\[switch-to-buffer-other-window] RET to restore the other window.")))
         (substitute-command-keys
          (gettext "  \\[scroll-other-window] to scroll the help."))))))

(defcustom help-selects-help-window t
  "*If nil, use the \"old Emacs\" behavior for Help buffers.
This just displays the buffer in another window, rather than selecting
the window."
  :type 'boolean
  :group 'help-appearance)

(defcustom help-max-help-buffers 10
  "*Maximum help buffers to allow before they start getting killed.
If this is a positive integer, before a help buffer is displayed
by `with-displaying-help-buffer', any excess help buffers which
are not being displayed are first killed.  Otherwise, if it is
zero or nil, only one help buffer, \"*Help*\" is ever used."
  :type '(choice integer (const :tag "None" nil))
  :group 'help-appearance)

(defvar help-buffer-list nil
  "List of help buffers used by `help-register-and-maybe-prune-excess'")

(defun help-register-and-maybe-prune-excess (newbuf)
  "Register use of a help buffer and possibly kill any excess ones."
  ;; remove new buffer from list
  (setq help-buffer-list (remove newbuf help-buffer-list))
  ;; maybe kill excess help buffers
  (if (and (integerp help-max-help-buffers)
           (> (length help-buffer-list) help-max-help-buffers))
      (let ((keep-list nil)
            (num-kill (- (length help-buffer-list)
                         help-max-help-buffers)))
        (while help-buffer-list
          (let ((buf (car help-buffer-list)))
            (if (and (or (equal buf newbuf) (get-buffer buf))
                     (string-match "^*Help" buf)
                     (save-excursion (set-buffer buf)
                                     (eq major-mode 'help-mode)))
                (if (and (>= num-kill (length help-buffer-list))
                         (not (get-buffer-window buf t t)))
                    (kill-buffer buf)
                  (setq keep-list (cons buf keep-list)))))
          (setq help-buffer-list (cdr help-buffer-list)))
        (setq help-buffer-list (nreverse keep-list))))
  ;; push new buffer
  (setq help-buffer-list (cons newbuf help-buffer-list)))

(defvar help-buffer-prefix-string "Help"
  "Initial string to use in constructing help buffer names.
You should never set this directory, only let-bind it.")

(defun help-buffer-name (name)
  "Return a name for a Help buffer using string NAME for context."
  (if (and (integerp help-max-help-buffers)
           (> help-max-help-buffers 0)
           (stringp name))
      (if help-buffer-prefix-string
	  (format "*%s: %s*" help-buffer-prefix-string name)
	(format "*%s*" name))
    (format "*%s*" help-buffer-prefix-string)))

;; Use this function for displaying help when C-h something is pressed
;; or in similar situations.  Do *not* use it when you are displaying
;; a help message and then prompting for input in the minibuffer --
;; this macro usually selects the help buffer, which is not what you
;; want in those situations.

;; #### Should really be a macro to eliminate the requirement of
;; caller to code a lambda form in THUNK -- mrb

;; #### BEFORE you rush to make this a macro, think about backward
;; compatibility.  The right way would be to create a macro with
;; another name (which is a shame, because w-d-h-b is a perfect name
;; for a macro) that uses with-displaying-help-buffer internally.

(defun with-displaying-help-buffer (thunk &optional name)
  "Form which makes a help buffer with given NAME and evaluates BODY there.
The actual name of the buffer is generated by the function `help-buffer-name'."
  (let* ((winconfig (current-window-configuration))
	 (was-one-window (one-window-p))
	 (buffer-name (help-buffer-name name))
	 (help-not-visible
	  (not (and (windows-of-buffer buffer-name) ;shortcut
		    (memq (selected-frame)
			  (mapcar 'window-frame
				  (windows-of-buffer buffer-name)))))))
    (help-register-and-maybe-prune-excess buffer-name)
    (prog1 (with-output-to-temp-buffer buffer-name
	     (prog1 (funcall thunk)
	       (save-excursion
		 (set-buffer standard-output)
		 (help-mode))))
      (let ((helpwin (get-buffer-window buffer-name)))
	(when helpwin
	  (with-current-buffer (window-buffer helpwin)
	    ;; If the *Help* buffer is already displayed on this
	    ;; frame, don't override the previous configuration
	    (when help-not-visible
	      (set-frame-property (selected-frame)
				  'help-window-config winconfig)))
	  (when help-selects-help-window
	    (select-window helpwin))
	  (cond ((eq helpwin (selected-window))
		 (display-message 'command
		   (substitute-command-keys "Type \\[help-mode-quit] to remove help window, \\[scroll-up] to scroll the help.")))
		(was-one-window
		 (display-message 'command
		   (substitute-command-keys "Type \\[delete-other-windows] to remove help window, \\[scroll-other-window] to scroll the help.")))
		(t
		 (display-message 'command
		   (substitute-command-keys "Type \\[switch-to-buffer-other-window] to restore the other window, \\[scroll-other-window] to scroll the help.")))))))))

(defun describe-key (key)
  "Display documentation of the function invoked by KEY.
KEY is a string, or vector of events.
When called interactively, KEY may also be a menu selection."
  (interactive "kDescribe key: ")
  (let ((defn (key-or-menu-binding key))
	(key-string (key-description key)))
    (if (or (null defn) (integerp defn))
        (message "%s is undefined" key-string)
      (with-displaying-help-buffer
       (lambda ()
	 (princ key-string)
	 (princ " runs ")
	 (if (symbolp defn)
	     (princ (format "`%s'" defn))
	   (princ defn))
	 (princ "\n\n")
	 (cond ((or (stringp defn) (vectorp defn))
		(let ((cmd (key-binding defn)))
		  (if (not cmd)
		      (princ "a keyboard macro")
		    (progn
		      (princ "a keyboard macro which runs the command ")
		      (princ cmd)
		      (princ ":\n\n")
		      (if (documentation cmd) (princ (documentation cmd)))))))
	       ((and (consp defn) (not (eq 'lambda (car-safe defn))))
		(let ((describe-function-show-arglist nil))
		  (describe-function-1 (car defn))))
	       ((symbolp defn)
		(describe-function-1 defn))
	       ((documentation defn)
		(princ (documentation defn)))
	       (t
		(princ "not documented"))))
       (format "key `%s'" key-string)))))

(defun describe-mode ()
  "Display documentation of current major mode and minor modes.
For this to work correctly for a minor mode, the mode's indicator variable
\(listed in `minor-mode-alist') must also be a function whose documentation
describes the minor mode."
  (interactive)
  (with-displaying-help-buffer
   (lambda ()
     ;; XEmacs change: print the major-mode documentation before
     ;; the minor modes.
     (princ mode-name)
     (princ " mode:\n")
     (princ (documentation major-mode))
     (princ "\n\n----\n\n")
     (let ((minor-modes minor-mode-alist))
       (while minor-modes
	 (let* ((minor-mode (car (car minor-modes)))
		(indicator (car (cdr (car minor-modes)))))
	   ;; Document a minor mode if it is listed in minor-mode-alist,
	   ;; bound locally in this buffer, non-nil, and has a function
	   ;; definition.
	   (if (and (boundp minor-mode)
		    (symbol-value minor-mode)
		    (fboundp minor-mode))
	       (let ((pretty-minor-mode minor-mode))
		 (if (string-match "-mode\\'" (symbol-name minor-mode))
		     (setq pretty-minor-mode
			   (capitalize
			    (substring (symbol-name minor-mode)
				       0 (match-beginning 0)))))
		 (while (and (consp indicator) (extentp (car indicator)))
		   (setq indicator (cdr indicator)))
		 (while (and indicator (symbolp indicator))
		   (setq indicator (symbol-value indicator)))
		 (princ (format "%s minor mode (indicator%s):\n"
				pretty-minor-mode indicator))
		 (princ (documentation minor-mode))
		 (princ "\n\n----\n\n"))))
	 (setq minor-modes (cdr minor-modes)))))
   (format "%s mode" mode-name)))

;; So keyboard macro definitions are documented correctly
(fset 'defining-kbd-macro (symbol-function 'start-kbd-macro))

(defun describe-distribution ()
  "Display info on how to obtain the latest version of XEmacs."
  (interactive)
  (find-file-read-only
   (locate-data-file "DISTRIB")))

(defun describe-beta ()
  "Display info on how to deal with Beta versions of XEmacs."
  (interactive)
  (find-file-read-only
   (locate-data-file "BETA"))
  (goto-char (point-min)))

(defun describe-copying ()
  "Display info on how you may redistribute copies of XEmacs."
  (interactive)
  (find-file-read-only
   (locate-data-file "COPYING"))
  (goto-char (point-min)))

(defun describe-pointer ()
  "Show a list of all defined mouse buttons, and their definitions."
  (interactive)
  (describe-bindings nil t))

(defun describe-project ()
  "Display info on the GNU project."
  (interactive)
  (find-file-read-only
   (locate-data-file "GNU"))
  (goto-char (point-min)))

(defun describe-no-warranty ()
  "Display info on all the kinds of warranty XEmacs does NOT have."
  (interactive)
  (describe-copying)
  (let (case-fold-search)
    (search-forward "NO WARRANTY")
    (recenter 0)))

(defun describe-bindings (&optional prefix mouse-only-p)
  "Show a list of all defined keys, and their definitions.
The list is put in a buffer, which is displayed.
If the optional argument PREFIX is supplied, only commands which
start with that sequence of keys are described.
If the second argument (prefix arg, interactively) is non-null
then only the mouse bindings are displayed."
  (interactive (list nil current-prefix-arg))
  (with-displaying-help-buffer
   (lambda ()
     (describe-bindings-1 prefix mouse-only-p))
   (format "bindings for %s" major-mode)))

(defun describe-bindings-1 (&optional prefix mouse-only-p)
  (let ((heading (if mouse-only-p
            (gettext "button          binding\n------          -------\n")
            (gettext "key             binding\n---             -------\n")))
        (buffer (current-buffer))
        (minor minor-mode-map-alist)
        (local (current-local-map))
        (shadow '()))
    (set-buffer standard-output)
    (while minor
      (let ((sym (car (car minor)))
            (map (cdr (car minor))))
        (if (symbol-value-in-buffer sym buffer nil)
            (progn
              (insert (format "Minor Mode Bindings for `%s':\n"
                              sym)
                      heading)
              (describe-bindings-internal map nil shadow prefix mouse-only-p)
              (insert "\n")
              (setq shadow (cons map shadow))))
        (setq minor (cdr minor))))
    (if local
        (progn
          (insert "Local Bindings:\n" heading)
          (describe-bindings-internal local nil shadow prefix mouse-only-p)
          (insert "\n")
          (setq shadow (cons local shadow))))
    (insert "Global Bindings:\n" heading)
    (describe-bindings-internal (current-global-map)
                                nil shadow prefix mouse-only-p)
    (when (and prefix function-key-map (not mouse-only-p))
      (insert "\nFunction key map translations:\n" heading)
      (describe-bindings-internal function-key-map nil nil
				  prefix mouse-only-p))
    (set-buffer buffer)
    standard-output))

(defun describe-prefix-bindings ()
  "Describe the bindings of the prefix used to reach this command.
The prefix described consists of all but the last event
of the key sequence that ran this command."
  (interactive)
  (let* ((key (this-command-keys))
	 (prefix (make-vector (1- (length key)) nil))
	 i)
    (setq i 0)
    (while (< i (length prefix))
      (aset prefix i (aref key i))
      (setq i (1+ i)))
    (with-displaying-help-buffer
     (lambda ()
       (princ "Key bindings starting with ")
       (princ (key-description prefix))
       (princ ":\n\n")
       (describe-bindings-1 prefix nil))
     (format "%s prefix" (key-description prefix)))))

;; Make C-h after a prefix, when not specifically bound,
;; run describe-prefix-bindings.
(setq prefix-help-command 'describe-prefix-bindings)

(defun describe-installation ()
  "Display a buffer showing information about this XEmacs was compiled."
  (interactive)
  (if (and (boundp 'Installation-string)
	   (stringp Installation-string))
      (with-displaying-help-buffer
       (lambda ()
	 (princ Installation-string))
       "Installation")
    (error "No Installation information available.")))

(defun view-emacs-news ()
  "Display info on recent changes to XEmacs."
  (interactive)
  (find-file (locate-data-file "NEWS")))

(defun xemacs-www-page ()
  "Go to the XEmacs World Wide Web page."
  (interactive)
  (if (boundp 'browse-url-browser-function)
      (funcall browse-url-browser-function "http://www.xemacs.org/")
    (error "xemacs-www-page requires browse-url")))

(defun xemacs-www-faq ()
  "View the latest and greatest XEmacs FAQ using the World Wide Web."
  (interactive)
  (if (boundp 'browse-url-browser-function)
      (funcall browse-url-browser-function
	       "http://www.xemacs.org/faq/index.html")
    (error "xemacs-www-faq requires browse-url")))

(defun xemacs-local-faq ()
  "View the local copy of the XEmacs FAQ.
If you have access to the World Wide Web, you should use `xemacs-www-faq'
instead, to ensure that you get the most up-to-date information."
  (interactive)
  (save-window-excursion
    (info)
    (Info-find-node "xemacs-faq" "Top"))
  (switch-to-buffer "*info*"))

(defcustom view-lossage-key-count 100
  "*Number of keys `view-lossage' shows.
The maximum number of available keys is governed by `recent-keys-ring-size'."
  :type 'integer
  :group 'help)

(defcustom view-lossage-message-count 100
  "*Number of minibuffer messages `view-lossage' shows."
  :type 'integer
  :group 'help)

(defun print-recent-messages (n)
  "Print N most recent messages to standard-output, most recent first.
If N is nil, all messages will be printed."
  (save-excursion
    (let ((buffer (get-buffer-create " *Message-Log*"))
	  oldpoint extent)
      (goto-char (point-max buffer) buffer)
      (set-buffer standard-output)
      (while (and (not (bobp buffer))
		  (or (null n) (>= (decf n) 0)))
	(setq oldpoint (point buffer))
	(setq extent (extent-at oldpoint buffer
				'message-multiline nil 'before))
	;; If the message was multiline, move all the way to the
	;; beginning.
	(if extent
	    (goto-char (extent-start-position extent) buffer)
	  (forward-line -1 buffer))
	(insert-buffer-substring buffer (point buffer) oldpoint)))))

(defun view-lossage ()
  "Display recent input keystrokes and recent minibuffer messages.
The number of keys shown is controlled by `view-lossage-key-count'.
The number of messages shown is controlled by `view-lossage-message-count'."
  (interactive)
  (with-displaying-help-buffer
   (lambda ()
     (princ (key-description (recent-keys view-lossage-key-count)))
     (save-excursion
       (set-buffer standard-output)
       (goto-char (point-min))
       (insert "Recent keystrokes:\n\n")
       (while (progn (move-to-column 50) (not (eobp)))
	 (search-forward " " nil t)
	 (insert "\n")))
     ;; XEmacs addition: copy the messages from " *Message-Log*",
     ;; reversing their order and handling multiline messages
     ;; correctly.
     (princ "\n\n\nRecent minibuffer messages (most recent first):\n\n")
     (print-recent-messages view-lossage-message-count))
   "lossage"))

(define-function 'help 'help-for-help)

(make-help-screen help-for-help
  "A B C F I K L M N P S T V W C-c C-d C-f C-i C-k C-n C-w;  ? for more help:"
  "Type a Help option:
\(Use SPC or DEL to scroll through this text.  Type \\<help-map>\\[help-quit] to exit the Help command.)

\\[hyper-apropos]	Type a substring; it shows a hypertext list of
        functions and variables that contain that substring.
	See also the `apropos' command.
\\[command-apropos]	Type a substring; it shows a list of commands
        (interactively callable functions) that contain that substring.
\\[describe-bindings]	Table of all key bindings.
\\[describe-key-briefly]	Type a command key sequence;
        it displays the function name that sequence runs.
\\[customize]	Customize Emacs options.
\\[Info-goto-emacs-command-node]	Type a function name; it displays the Info node for that command.
\\[describe-function]	Type a function name; it shows its documentation.
\\[Info-elisp-ref]	Type a function name; it jumps to the full documentation
	in the XEmacs Lisp Programmer's Manual.
\\[xemacs-local-faq]	Local copy of the XEmacs FAQ.
\\[info]	Info documentation reader.
\\[Info-query]	Type an Info file name; it displays it in Info reader.
\\[describe-key]	Type a command key sequence;
        it displays the documentation for the command bound to that key.
\\[Info-goto-emacs-key-command-node]	Type a command key sequence;
        it displays the Info node for the command bound to that key.
\\[view-lossage]	Recent input keystrokes and minibuffer messages.
\\[describe-mode]	Documentation of current major and minor modes.
\\[view-emacs-news]	News of recent XEmacs changes.
\\[finder-by-keyword]	Type a topic keyword; it finds matching packages.
\\[describe-pointer]	Table of all mouse-button bindings.
\\[describe-syntax]	Contents of syntax table with explanations.
\\[help-with-tutorial]	XEmacs learn-by-doing tutorial.
\\[describe-variable]	Type a variable name; it displays its documentation and value.
\\[where-is]	Type a command name; it displays which keystrokes invoke that command.
\\[describe-distribution]	XEmacs ordering information.
\\[describe-no-warranty]	Information on absence of warranty for XEmacs.
\\[describe-copying]	XEmacs copying permission (General Public License)."
  help-map)

(defmacro with-syntax-table (syntab &rest body)
  "Evaluate BODY with the syntax-table SYNTAB"
  `(let ((stab (syntax-table)))
     (unwind-protect
	 (progn
	   (set-syntax-table (copy-syntax-table ,syntab))
	   ,@body)
       (set-syntax-table stab))))
(put 'with-syntax-table 'lisp-indent-function 1)
(put 'with-syntax-table 'edebug-form-spec '(form body))

(defun function-called-at-point ()
  "Return the function which is called by the list containing point.
If that gives no function, return the function whose name is around point.
If that doesn't give a function, return nil."
  (or (ignore-errors
	(save-excursion
	  (save-restriction
	    (narrow-to-region (max (point-min) (- (point) 1000))
			      (point-max))
	    (backward-up-list 1)
	    (forward-char 1)
	    (let (obj)
	      (setq obj (read (current-buffer)))
	      (and (symbolp obj) (fboundp obj) obj)))))
      (ignore-errors
	(with-syntax-table emacs-lisp-mode-syntax-table
	  (save-excursion
	    (or (not (zerop (skip-syntax-backward "_w")))
		(eq (char-syntax (char-after (point))) ?w)
		(eq (char-syntax (char-after (point))) ?_)
		(forward-sexp -1))
	    (skip-chars-forward "`'")
	    (let ((obj (read (current-buffer))))
	      (and (symbolp obj) (fboundp obj) obj)))))))

(defun function-at-point ()
  "Return the function whose name is around point.
If that gives no function, return the function which is called by the
list containing point.  If that doesn't give a function, return nil."
  (or (ignore-errors
	(with-syntax-table emacs-lisp-mode-syntax-table
	  (save-excursion
	    (or (not (zerop (skip-syntax-backward "_w")))
		(eq (char-syntax (char-after (point))) ?w)
		(eq (char-syntax (char-after (point))) ?_)
		(forward-sexp -1))
	    (skip-chars-forward "`'")
	    (let ((obj (read (current-buffer))))
	      (and (symbolp obj) (fboundp obj) obj)))))
      (ignore-errors
	(save-excursion
	  (save-restriction
	    (narrow-to-region (max (point-min) (- (point) 1000))
			      (point-max))
	    (backward-up-list 1)
	    (forward-char 1)
	    (let (obj)
	      (setq obj (read (current-buffer)))
	      (and (symbolp obj) (fboundp obj) obj)))))))

;; Default to nil for the non-hackers?  Not until we find a way to
;; distinguish hackers from non-hackers automatically!
(defcustom describe-function-show-arglist t
  "*If non-nil, describe-function will show its arglist,
unless the function is autoloaded."
  :type 'boolean
  :group 'help-appearance)

(defun describe-symbol-find-file (symbol)
  (loop for (file . load-data) in load-history
    do (when (memq symbol load-data)
	 (return file))))

(define-obsolete-function-alias
  'describe-function-find-file
  'describe-symbol-find-file)

(defun describe-function (function)
  "Display the full documentation of FUNCTION (a symbol).
When run interactively, it defaults to any function found by
`function-at-point'."
  (interactive
    (let* ((fn (function-at-point))
           (val (let ((enable-recursive-minibuffers t))
                  (completing-read
                    (if fn
                        (format (gettext "Describe function (default %s): ")
				fn)
                        (gettext "Describe function: "))
                    obarray 'fboundp t nil 'function-history))))
      (list (if (equal val "") fn (intern val)))))
  (with-displaying-help-buffer
   (lambda ()
     (describe-function-1 function)
     ;; Return the text we displayed.
     (buffer-string nil nil standard-output))
    (format "function `%s'" function)))

(defun function-obsolete-p (function)
  "Return non-nil if FUNCTION is obsolete."
  (not (null (get function 'byte-obsolete-info))))

(defun function-obsoleteness-doc (function)
  "If FUNCTION is obsolete, return a string describing this."
  (let ((obsolete (get function 'byte-obsolete-info)))
    (if obsolete
	(format "Obsolete; %s"
		(if (stringp (car obsolete))
		    (car obsolete)
		  (format "use `%s' instead." (car obsolete)))))))

(defun function-compatible-p (function)
  "Return non-nil if FUNCTION is present for Emacs compatibility."
  (not (null (get function 'byte-compatible-info))))

(defun function-compatibility-doc (function)
  "If FUNCTION is Emacs compatible, return a string describing this."
  (let ((compatible (get function 'byte-compatible-info)))
    (if compatible
	(format "Emacs Compatible; %s"
		(if (stringp (car compatible))
		    (car compatible)
		  (format "use `%s' instead." (car compatible)))))))

;Here are all the possibilities below spelled out, for the benefit
;of the I18N3 snarfer.
;
;(gettext "a built-in function")
;(gettext "an interactive built-in function")
;(gettext "a built-in macro")
;(gettext "an interactive built-in macro")
;(gettext "a compiled Lisp function")
;(gettext "an interactive compiled Lisp function")
;(gettext "a compiled Lisp macro")
;(gettext "an interactive compiled Lisp macro")
;(gettext "a Lisp function")
;(gettext "an interactive Lisp function")
;(gettext "a Lisp macro")
;(gettext "an interactive Lisp macro")
;(gettext "a mocklisp function")
;(gettext "an interactive mocklisp function")
;(gettext "a mocklisp macro")
;(gettext "an interactive mocklisp macro")
;(gettext "an autoloaded Lisp function")
;(gettext "an interactive autoloaded Lisp function")
;(gettext "an autoloaded Lisp macro")
;(gettext "an interactive autoloaded Lisp macro")

;; taken out of `describe-function-1'
(defun function-arglist (function)
  "Return a string giving the argument list of FUNCTION.
For example:

	(function-arglist 'function-arglist)
	=> (function-arglist FUNCTION)

This function is used by `describe-function-1' to list function
arguments in the standard Lisp style."
  (let* ((fndef (indirect-function function))
	 (arglist
	 (cond ((compiled-function-p fndef)
		(compiled-function-arglist fndef))
	       ((eq (car-safe fndef) 'lambda)
		(nth 1 fndef))
	       ((subrp fndef)
		(let* ((doc (documentation function))
		       (args (and (string-match
				   "[\n\t ]*\narguments: ?(\\(.*\\))\n?\\'"
				   doc)
				  (match-string 1 doc))))
		  ;; If there are no arguments documented for the
		  ;; subr, rather don't print anything.
		  (cond ((null args) t)
			((equal args "") nil)
			(args))))
	       (t t))))
    (cond ((listp arglist)
	   (prin1-to-string
	    (cons function (mapcar (lambda (arg)
				     (if (memq arg '(&optional &rest))
					 arg
				       (intern (upcase (symbol-name arg)))))
				   arglist))
	    t))
	  ((stringp arglist)
	   (format "(%s %s)" function arglist)))))

(defun function-documentation (function &optional strip-arglist)
  "Return a string giving the documentation for FUNCTION, if any.
If the optional argument STRIP-ARGLIST is non-nil, remove the arglist
part of the documentation of internal subroutines."
  (let ((doc (condition-case nil
		 (or (documentation function)
		     (gettext "not documented"))
	       (void-function ""))))
    (if (and strip-arglist
	     (string-match "[\n\t ]*\narguments: ?(\\(.*\\))\n?\\'" doc))
	(setq doc (substring doc 0 (match-beginning 0))))
    doc))

(defun describe-function-1 (function &optional nodoc)
  "This function does the work for `describe-function'."
  (princ (format "`%s' is " function))
  (let* ((def function)
	 aliases file-name autoload-file kbd-macro-p fndef macrop)
    (while (and (symbolp def) (fboundp def))
      (when (not (eq def function))
	(setq aliases
	      (if aliases
		  ;; I18N3 Need gettext due to concat
		  (concat aliases
			  (format
			   "\n     which is an alias for `%s', "
			   (symbol-name def)))
		(format "an alias for `%s', " (symbol-name def)))))
      (setq def (symbol-function def)))
    (if (and (fboundp 'compiled-function-annotation)
	     (compiled-function-p def))
	(setq file-name (compiled-function-annotation def)))
    (if (eq 'macro (car-safe def))
	(setq fndef (cdr def)
	      file-name (and (compiled-function-p (cdr def))
			     (fboundp 'compiled-function-annotation)
			     (compiled-function-annotation (cdr def)))
	      macrop t)
      (setq fndef def))
    (if aliases (princ aliases))
    (let ((int #'(lambda (string an-p macro-p)
		   (princ (format
			   (gettext (concat
				     (cond ((commandp def)
					    "an interactive ")
					   (an-p "an ")
					   (t "a "))
				     "%s"
				     (if macro-p " macro" " function")))
			   string)))))
      (cond ((or (stringp def) (vectorp def))
             (princ "a keyboard macro.")
	     (setq kbd-macro-p t))
            ((subrp fndef)
             (funcall int "built-in" nil macrop))
            ((compiled-function-p fndef)
             (funcall int "compiled Lisp" nil macrop))
            ((eq (car-safe fndef) 'lambda)
             (funcall int "Lisp" nil macrop))
            ((eq (car-safe fndef) 'mocklisp)
             (funcall int "mocklisp" nil macrop))
            ((eq (car-safe def) 'autoload)
	     (setq autoload-file (elt def 1))
	     (funcall int "autoloaded Lisp" t (elt def 4)))
	    ((and (symbolp def) (not (fboundp def)))
	     (princ "a symbol with a void (unbound) function definition."))
            (t
             nil)))
    (princ "\n")
    (if autoload-file
	(princ (format "  -- autoloads from \"%s\"\n" autoload-file)))
    (or file-name
	(setq file-name (describe-symbol-find-file function)))
    (if file-name
	(princ (format "  -- loaded from \"%s\"\n" file-name)))
;;     (terpri)
    (if describe-function-show-arglist
	(let ((arglist (function-arglist function)))
	  (when arglist
	    (princ arglist)
	    (terpri))))
    (terpri)
    (cond (kbd-macro-p
	   (princ "These characters are executed:\n\n\t")
	   (princ (key-description def))
	   (cond ((setq def (key-binding def))
		  (princ (format "\n\nwhich executes the command `%s'.\n\n"
				 def))
		  (describe-function-1 def))))
	  (nodoc nil)
	  (t
	   ;; tell the user about obsoleteness.
	   ;; If the function is obsolete and is aliased, don't
	   ;; even bother to report the documentation, as a further
	   ;; encouragement to use the new function.
	   (let ((obsolete (function-obsoleteness-doc function))
		 (compatible (function-compatibility-doc function)))
	     (when obsolete
	       (princ obsolete)
	       (terpri)
	       (terpri))
	     (when compatible
	       (princ compatible)
	       (terpri)
	       (terpri))
	     (unless (and obsolete aliases)
	       (let ((doc (function-documentation function t)))
		 (princ "Documentation:\n")
		 (princ doc)
		 (unless (or (equal doc "")
			     (eq ?\n (aref doc (1- (length doc)))))
		   (terpri)))))))))


;;; [Obnoxious, whining people who complain very LOUDLY on Usenet
;;; are binding this to keys.]
(defun describe-function-arglist (function)
  (interactive (list (or (function-at-point)
			 (error "no function call at point"))))
  (message nil)
  (message (function-arglist function)))


(defun variable-at-point ()
  (ignore-errors
    (with-syntax-table emacs-lisp-mode-syntax-table
      (save-excursion
	(or (not (zerop (skip-syntax-backward "_w")))
	    (eq (char-syntax (char-after (point))) ?w)
	    (eq (char-syntax (char-after (point))) ?_)
	    (forward-sexp -1))
	(skip-chars-forward "'")
	(let ((obj (read (current-buffer))))
	  (and (symbolp obj) (boundp obj) obj))))))

(defun variable-obsolete-p (variable)
  "Return non-nil if VARIABLE is obsolete."
  (not (null (get variable 'byte-obsolete-variable))))

(defun variable-obsoleteness-doc (variable)
  "If VARIABLE is obsolete, return a string describing this."
  (let ((obsolete (get variable 'byte-obsolete-variable)))
    (if obsolete
	(format "Obsolete; %s"
		(if (stringp obsolete)
		    obsolete
		  (format "use `%s' instead." obsolete))))))

(defun variable-compatible-p (variable)
  "Return non-nil if VARIABLE is Emacs compatible."
  (not (null (get variable 'byte-compatible-variable))))

(defun variable-compatibility-doc (variable)
  "If VARIABLE is Emacs compatible, return a string describing this."
  (let ((compatible (get variable 'byte-compatible-variable)))
    (if compatible
	(format "Emacs Compatible; %s"
		(if (stringp compatible)
		    compatible
		  (format "use `%s' instead." compatible))))))

(defun built-in-variable-doc (variable)
  "Return a string describing whether VARIABLE is built-in."
  (let ((type (built-in-variable-type variable)))
    (case type
      (integer "a built-in integer variable")
      (const-integer "a built-in constant integer variable")
      (boolean "a built-in boolean variable")
      (const-boolean "a built-in constant boolean variable")
      (object "a simple built-in variable")
      (const-object "a simple built-in constant variable")
      (const-specifier "a built-in constant specifier variable")
      (current-buffer "a built-in buffer-local variable")
      (const-current-buffer "a built-in constant buffer-local variable")
      (default-buffer "a built-in default buffer-local variable")
      (selected-console "a built-in console-local variable")
      (const-selected-console "a built-in constant console-local variable")
      (default-console "a built-in default console-local variable")
      (t
       (if type "an unknown type of built-in variable?"
	 "a variable declared in Lisp")))))

(defun describe-variable (variable)
  "Display the full documentation of VARIABLE (a symbol)."
  (interactive
   (let* ((v (variable-at-point))
          (val (let ((enable-recursive-minibuffers t))
                 (completing-read
                   (if v
                       (format "Describe variable (default %s): " v)
                       (gettext "Describe variable: "))
                   obarray 'boundp t nil 'variable-history))))
     (list (if (equal val "") v (intern val)))))
  (with-displaying-help-buffer
   (lambda ()
     (let ((origvar variable)
	   aliases)
       (let ((print-escape-newlines t))
	 (princ (format "`%s' is " (symbol-name variable)))
	 (while (variable-alias variable)
	   (let ((newvar (variable-alias variable)))
	     (if aliases
		 ;; I18N3 Need gettext due to concat
		 (setq aliases
		       (concat aliases
			       (format "\n     which is an alias for `%s',"
				       (symbol-name newvar))))
	       (setq aliases
		     (format "an alias for `%s',"
			     (symbol-name newvar))))
	     (setq variable newvar)))
	 (if aliases
	     (princ (format "%s" aliases)))
	 (princ (built-in-variable-doc variable))
	 (princ ".\n")
	 (let ((file-name (describe-symbol-find-file variable)))
	   (if file-name
	       (princ (format "  -- loaded from \"%s\"\n" file-name))))
	 (princ "\nValue: ")
	 (if (not (boundp variable))
	     (princ "void\n")
	   (prin1 (symbol-value variable))
	   (terpri))
	 (terpri)
	 (cond ((local-variable-p variable (current-buffer))
		(let* ((void (cons nil nil))
		       (def (condition-case nil
				(default-value variable)
			      (error void))))
		  (princ "This value is specific to the current buffer.\n")
		  (if (local-variable-p variable nil)
		      (princ "(Its value is local to each buffer.)\n"))
		  (terpri)
		  (if (if (eq def void)
			  (boundp variable)
			(not (eq (symbol-value variable) def)))
		      ;; #### I18N3 doesn't localize properly!
		      (progn (princ "Default-value: ")
			     (if (eq def void)
				 (princ "void\n")
			       (prin1 def)
			       (terpri))
			     (terpri)))))
	       ((local-variable-p variable (current-buffer) t)
		(princ "Setting it would make its value buffer-local.\n\n"))))
       (princ "Documentation:")
       (terpri)
       (let ((doc (documentation-property variable 'variable-documentation))
	     (obsolete (variable-obsoleteness-doc origvar))
	     (compatible (variable-compatibility-doc origvar)))
	 (when obsolete
	   (princ obsolete)
	   (terpri)
	   (terpri))
	 (when compatible
	   (princ compatible)
	   (terpri)
	   (terpri))
	 ;; don't bother to print anything if variable is obsolete and aliased.
	 (when (or (not obsolete) (not aliases))
	   (if doc
	       ;; note: documentation-property calls substitute-command-keys.
	       (princ doc)
	     (princ "not documented as a variable."))))
       (terpri)))
   (format "variable `%s'" variable)))

(defun sorted-key-descriptions (keys &optional separator)
  "Sort and separate the key descriptions for KEYS.
The sorting is done by length (shortest bindings first), and the bindings
are separated with SEPARATOR (\", \" by default)."
  (mapconcat 'key-description
	     (sort keys #'(lambda (x y)
			    (< (length x) (length y))))
	     (or separator ", ")))

(defun where-is (definition &optional insert)
  "Print message listing key sequences that invoke specified command.
Argument is a command definition, usually a symbol with a function definition.
When run interactively, it defaults to any function found by
`function-at-point'.
If INSERT (the prefix arg) is non-nil, insert the message in the buffer."
  (interactive
   (let ((fn (function-at-point))
	 (enable-recursive-minibuffers t)
	 val)
     (setq val (read-command
		(if fn (format "Where is command (default %s): " fn)
		  "Where is command: ")))
     (list (if (equal (symbol-name val) "")
	       fn val)
	   current-prefix-arg)))
  (let ((keys (where-is-internal definition)))
    (if keys
	(if insert
	    (princ (format "%s (%s)" (sorted-key-descriptions keys)
			   definition) (current-buffer))
	  (message "%s is on %s" definition (sorted-key-descriptions keys)))
      (if insert
	  (princ (format (if (commandp definition) "M-x %s RET"
			   "M-: (%s ...)") definition) (current-buffer))
	(message "%s is not on any keys" definition))))
  nil)

;; `locate-library' moved to "packages.el"


;; Functions ported from C into Lisp in XEmacs

(defun describe-syntax ()
  "Describe the syntax specifications in the syntax table.
The descriptions are inserted in a buffer, which is then displayed."
  (interactive)
  (with-displaying-help-buffer
   (lambda ()
     ;; defined in syntax.el
     (describe-syntax-table (syntax-table) standard-output))
   (format "syntax-table for %s" major-mode)))

(defun list-processes ()
  "Display a list of all processes.
\(Any processes listed as Exited or Signaled are actually eliminated
after the listing is made.)"
  (interactive)
  (with-output-to-temp-buffer "*Process List*"
    (set-buffer standard-output)
    (buffer-disable-undo standard-output)
    (make-local-variable 'truncate-lines)
    (setq truncate-lines t)
    ;;      00000000001111111111222222222233333333334444444444
    ;;      01234567890123456789012345678901234567890123456789
    ;; rewritten for I18N3.  This one should stay rewritten
    ;; so that the dashes will line up properly.
    (princ "Proc         Status   Buffer         Tty         Command\n----         ------   ------         ---         -------\n")
    (let ((tail (process-list)))
      (while tail
	(let* ((p (car tail))
	       (pid (process-id p))
	       (s (process-status p)))
	  (setq tail (cdr tail))
	  (princ (format "%-13s" (process-name p)))
	  (princ s)
	  (if (and (eq s 'exit) (/= (process-exit-status p) 0))
	      (princ (format " %d" (process-exit-status p))))
	  (if (memq s '(signal exit closed))
	      ;; Do delete-exited-processes' work
	      (delete-process p))
	  (indent-to 22 1)		;####
	  (let ((b (process-buffer p)))
	    (cond ((not b)
		   (princ "(none)"))
		  ((not (buffer-name b))
		   (princ "(killed)"))
		  (t
		   (princ (buffer-name b)))))
	  (indent-to 37 1)		;####
	  (let ((tn (process-tty-name p)))
	    (cond ((not tn)
		   (princ "(none)"))
		  (t
		   (princ (format "%s" tn)))))
	  (indent-to 49 1)		;####
	  (if (not (integerp pid))
	      (progn
		(princ "network stream connection ")
		(princ (car pid))
		(princ "@")
		(princ (cdr pid)))
	    (let ((cmd (process-command p)))
	      (while cmd
		(princ (car cmd))
		(setq cmd (cdr cmd))
		(if cmd (princ " ")))))
	  (terpri))))))

;; Stop gap for 21.0 untill we do help-char etc properly.
(defun help-keymap-with-help-key (keymap form)
  "Return a copy of KEYMAP with an help-key binding according to help-char
 invoking FORM like help-form.  An existing binding is not overridden.
 If FORM is nil then no binding is made."
  (let ((map (copy-keymap keymap))
	(key (if (characterp help-char)
		 (vector (character-to-event help-char))
	       help-char)))
    (when (and form key (not (lookup-key map key)))
      (define-key map key
	`(lambda () (interactive) (help-print-help-form ,form))))
    map))

(defun help-print-help-form (form)
  (let ((string (eval form)))
    (if (stringp string)
	(with-displaying-help-buffer
	 (insert string)))))


;;; help.el ends here
Tip: Filter by directory path e.g. /media app.js to search for public/media/app.js.
Tip: Use camelCasing e.g. ProjME to search for ProjectModifiedEvent.java.
Tip: Filter by extension type e.g. /repo .js to search for all .js files in the /repo directory.
Tip: Separate your search with spaces e.g. /ssh pom.xml to search for src/ssh/pom.xml.
Tip: Use ↑ and ↓ arrow keys to navigate and return to view the file.
Tip: You can also navigate files with Ctrl+j (next) and Ctrl+k (previous) and view the file with Ctrl+o.
Tip: You can also navigate files with Alt+j (next) and Alt+k (previous) and view the file with Alt+o.