scheme / xscheme.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
;;; xscheme.el --- Run MIT-Scheme under XEmacs
;; Keywords: languages, lisp

;; Copyright (C) 1986,87,89 Free Software Foundation, Inc.

;; Author: Unknown - Probably an MIT Teaching Staff member.
;; Maintainer: The XEmacs Development Team and its User Base.
;; Keywords: languages, processes
;; Version: 1.0-XEmacs

;; 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, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Synched up with: Not synched with FSF.

;;; Commentary:

;;; Requires C-Scheme release 5 or later
;;; Changes to Control-G handler require runtime version 13.85 or later

;;; You can obtain the Scheme language through:
;;; <URL:http://www.swiss.ai.mit.edu/scheme-home.html>
;;; This should work right out of the box, on most properly configured
;;; Linux systems.  It's the second easiest way to get started
;;; programming, next to XEmacs Lisp. :-)

;;; Code:
(require 'scheme)


(defgroup scheme nil
  "Scheme programming."
  :group 'languages)

(defcustom scheme-program-name "scheme"
  "*Program invoked by the `run-scheme' command."
  :type 'string
  :group 'scheme)

(defcustom scheme-band-name nil
  "*Band loaded by the `run-scheme' command."
  :type '(choice (const :tag "None" nil)
		 (string :tag "File" ""))
  :group 'scheme)

(defcustom scheme-program-arguments nil
  "*Arguments passed to the Scheme program by the `run-scheme' command."
  :type '(choice (const :tag "None" nil)
		 (string :tag "Args" ""))
  :group 'scheme)

(defcustom xscheme-allow-pipelined-evaluation t
  "If non-nil, an expression may be transmitted while another is evaluating.
Otherwise, attempting to evaluate an expression before the previous expression
has finished evaluating will signal an error."
  :type 'boolean
  :group 'scheme)

(defvar default-xscheme-runlight
  '(": " xscheme-runlight-string)
  "Default global (shared) xscheme-runlight modeline format.")

(defvar xscheme-startup-message
  "This is the Scheme process buffer.
Type \\[advertised-xscheme-send-previous-expression] to evaluate the expression before point.
Type \\[xscheme-send-control-g-interrupt] to abort evaluation.
Type \\[describe-mode] for more information.

"
  "String to insert into Scheme process buffer first time it is started.
Is processed with `substitute-command-keys' first.")

(defcustom xscheme-signal-death-message nil
  "If non-nil, causes a message to be generated when the Scheme process dies."
  :type 'boolean
  :group 'scheme)

(defvar xscheme-process-name "*scheme*"
  "*Process created by the `run-scheme' command.")

(defvar xscheme-buffer-name "*scheme*"
  "*Buffer created by the `run-scheme' command.")

(defun xscheme-evaluation-commands (keymap)
  (define-key keymap "\e\C-x" 'xscheme-send-definition)
  (define-key keymap "\C-x\C-e" 'advertised-xscheme-send-previous-expression)
  (define-key keymap "\eo" 'xscheme-send-buffer)
  (define-key keymap "\ez" 'xscheme-send-definition)
  (define-key keymap "\e\C-m" 'xscheme-send-previous-expression)
  (define-key keymap "\e\C-z" 'xscheme-send-region))

(defun xscheme-interrupt-commands (keymap)
  (define-key keymap "\C-c\C-s" 'xscheme-select-process-buffer)
  (define-key keymap "\C-c\C-b" 'xscheme-send-breakpoint-interrupt)
  (define-key keymap "\C-c\C-c" 'xscheme-send-control-g-interrupt)
  (define-key keymap "\C-c\C-u" 'xscheme-send-control-u-interrupt)
  (define-key keymap "\C-c\C-x" 'xscheme-send-control-x-interrupt))

(xscheme-evaluation-commands scheme-mode-map)
(xscheme-interrupt-commands scheme-mode-map)

;;;###autoload
(defun run-scheme (command-line)
  "Run an inferior Scheme process.
Output goes to the buffer `*scheme*'.
With argument, asks for a command line."
  (interactive
   (list (read-scheme-command-line current-prefix-arg)))
  (scheme-start command-line xscheme-process-name xscheme-buffer-name))

(defun reset-scheme ()
  "Reset the Scheme process."
  (interactive)
  (let ((process (get-process xscheme-process-name)))
    (cond ((or (not process)
	       (not (eq (process-status process) 'run))
	       (yes-or-no-p
"The Scheme process is running, are you SURE you want to reset it? "))
	   (message "Resetting Scheme process...")
	   (if process
	       (progn
		(kill-process process t)
		(delete-process process)))
	   (xscheme-start-process xscheme-process-command-line
				  xscheme-process-name
				  xscheme-buffer-name)
	   (message "Resetting Scheme process...done")))))

(defun scheme-start (command-line process-name buffer-name &optional avoid-set)
  (if (not avoid-set)
      (setq-default xscheme-process-command-line command-line))
  (switch-to-buffer
   (xscheme-start-process command-line process-name buffer-name))
  (make-local-variable 'xscheme-process-command-line)
  (setq xscheme-process-command-line command-line))

(defun read-scheme-command-line (arg)
  (let ((default
	  (or xscheme-process-command-line
	      (xscheme-default-command-line))))
    (if arg
	(read-string "Run Scheme: " default)
      default)))

(defun xscheme-default-command-line ()
  (concat scheme-program-name " -emacs"
	  (if scheme-program-arguments
	      (concat " " scheme-program-arguments)
	      "")
	  (if scheme-band-name
	      (concat " -band " scheme-band-name)
	      "")))

;;;; Multiple Scheme buffer management commands

(defun start-scheme (buffer-name &optional globally)
  "Choose a scheme interaction buffer, or create a new one."
  ;; (interactive "BScheme interaction buffer: \nP")
  (interactive
   (list (read-buffer "Scheme interaction buffer: "
		      xscheme-buffer-name
		      nil)
	 current-prefix-arg))
  (let ((buffer (get-buffer-create buffer-name)))
    (let ((process (get-buffer-process buffer)))
      (if process
	  (switch-to-buffer buffer)
	(if (or (not (buffer-file-name buffer))
		(yes-or-no-p (concat "Buffer "
				     (buffer-name buffer)
				     " contains file "
				     (buffer-file-name buffer)
				     "; start scheme in it? ")))
	    (progn
	      (scheme-start (read-scheme-command-line t)
			    buffer-name
			    buffer-name)
	      (if globally
		  (global-set-scheme-interaction-buffer buffer-name)))
	  (message "start-scheme aborted"))))))

(fset 'select-scheme 'start-scheme)

(defun global-set-scheme-interaction-buffer (buffer-name)
  "Set the default scheme interaction buffer."
  (interactive
   (list (read-buffer "Scheme interaction buffer: "
		      xscheme-buffer-name
		      t)))
  (let ((process-name (verify-xscheme-buffer buffer-name nil)))
    (setq-default xscheme-buffer-name buffer-name)
    (setq-default xscheme-process-name process-name)
    (setq-default xscheme-runlight-string
		  (save-excursion (set-buffer buffer-name)
				  xscheme-runlight-string))
    (setq-default xscheme-runlight
		  (if (eq (process-status process-name) 'run)
		      default-xscheme-runlight
		    ""))))

(defun local-set-scheme-interaction-buffer (buffer-name)
  "Set the scheme interaction buffer for the current buffer."
  (interactive
   (list (read-buffer "Scheme interaction buffer: "
		      xscheme-buffer-name
		      t)))
  (let ((process-name (verify-xscheme-buffer buffer-name t)))
    (make-local-variable 'xscheme-buffer-name)
    (setq xscheme-buffer-name buffer-name)
    (make-local-variable 'xscheme-process-name)
    (setq xscheme-process-name process-name)
    (make-local-variable 'xscheme-runlight)
    (setq xscheme-runlight (save-excursion (set-buffer buffer-name)
					   xscheme-runlight))))

(defun local-clear-scheme-interaction-buffer ()
  "Make the current buffer use the default scheme interaction buffer."
  (interactive)
  (if (xscheme-process-buffer-current-p)
      (error "Cannot change the interaction buffer of an interaction buffer"))
  (kill-local-variable 'xscheme-buffer-name)
  (kill-local-variable 'xscheme-process-name)
  (kill-local-variable 'xscheme-runlight))
  
(defun verify-xscheme-buffer (buffer-name localp)
  (if (and localp (xscheme-process-buffer-current-p))
      (error "Cannot change the interaction buffer of an interaction buffer"))
  (let* ((buffer (get-buffer buffer-name))
	 (process (and buffer (get-buffer-process buffer))))
    (cond ((not buffer)
	   (error "Buffer does not exist" buffer-name))
	  ((not process)
	   (error "Buffer is not a scheme interaction buffer" buffer-name))
	  (t
	   (save-excursion
	     (set-buffer buffer)
	     (if (not (xscheme-process-buffer-current-p))
		 (error "Buffer is not a scheme interaction buffer"
			buffer-name)))
	   (process-name process)))))

;;;; Interaction Mode

(defun scheme-interaction-mode (&optional preserve)
  "Major mode for interacting with the inferior Scheme process.
Like  scheme-mode  except that:

\\[advertised-xscheme-send-previous-expression] sends the expression before point to the Scheme process as input
\\[xscheme-yank-pop] yanks an expression previously sent to Scheme
\\[xscheme-yank-push] yanks an expression more recently sent to Scheme

All output from the Scheme process is written in the Scheme process
buffer, which is initially named \"*scheme*\".  The result of
evaluating a Scheme expression is also printed in the process buffer,
preceded by the string \";Value: \" to highlight it.  If the process
buffer is not visible at that time, the value will also be displayed
in the minibuffer.  If an error occurs, the process buffer will
automatically pop up to show you the error message.

While the Scheme process is running, the modelines of all buffers in
scheme-mode are modified to show the state of the process.  The
possible states and their meanings are:

input		waiting for input
run		evaluating
gc		garbage collecting

The process buffer's modeline contains additional information where
the buffer's name is normally displayed: the command interpreter level
and type.

Scheme maintains a stack of command interpreters.  Every time an error
or breakpoint occurs, the current command interpreter is pushed on the
command interpreter stack, and a new command interpreter is started.
One example of why this is done is so that an error that occurs while
you are debugging another error will not destroy the state of the
initial error, allowing you to return to it after the second error has
been fixed.

The command interpreter level indicates how many interpreters are in
the command interpreter stack.  It is initially set to one, and it is
incremented every time that stack is pushed, and decremented every
time it is popped.  The following commands are useful for manipulating
the command interpreter stack:

\\[xscheme-send-breakpoint-interrupt]	pushes the stack once
\\[xscheme-send-control-u-interrupt]	pops the stack once
\\[xscheme-send-control-g-interrupt]	pops everything off
\\[xscheme-send-control-x-interrupt]	aborts evaluation, doesn't affect stack

Some possible command interpreter types and their meanings are:

[Evaluator]	read-eval-print loop for evaluating expressions
[Debugger]	single character commands for debugging errors
[Where]		single character commands for examining environments

Starting with release 6.2 of Scheme, the latter two types of command
interpreters will change the major mode of the Scheme process buffer
to scheme-debugger-mode , in which the evaluation commands are
disabled, and the keys which normally self insert instead send
themselves to the Scheme process.  The command character ? will list
the available commands.

For older releases of Scheme, the major mode will be
scheme-interaction-mode , and the command characters must be sent as
if they were expressions.

Commands:
Delete converts tabs to spaces as it moves back.
Blank lines separate paragraphs.  Semicolons start comments.
\\{scheme-interaction-mode-map}

Entry to this mode calls the value of scheme-interaction-mode-hook
with no args, if that value is non-nil.
 Likewise with the value of scheme-mode-hook.
 scheme-interaction-mode-hook is called after scheme-mode-hook."

  (interactive "P")
  (if (not preserve)
      (let ((previous-mode major-mode))
        (kill-all-local-variables)
        (make-local-variable 'xscheme-previous-mode)
        (make-local-variable 'xscheme-buffer-name)
        (make-local-variable 'xscheme-process-name)
        (make-local-variable 'xscheme-previous-process-state)
        (make-local-variable 'xscheme-runlight-string)
        (make-local-variable 'xscheme-runlight)
        (setq xscheme-previous-mode previous-mode)
        (let ((buffer (current-buffer)))
          (setq xscheme-buffer-name (buffer-name buffer))
          (let ((process (get-buffer-process buffer)))
            (if (not process)
                (setq xscheme-previous-process-state (cons nil nil))
                (progn
                  (setq xscheme-process-name (process-name process))
                  (setq xscheme-previous-process-state
                        (cons (process-filter process)
                              (process-sentinel process)))
		  (xscheme-process-filter-initialize t)
		  (xscheme-modeline-initialize xscheme-buffer-name)
		  (set-process-sentinel process 'xscheme-process-sentinel)
		  (set-process-filter process 'xscheme-process-filter)))))))
  (scheme-interaction-mode-initialize)
  (scheme-mode-variables)
  (run-hooks 'scheme-mode-hook 'scheme-interaction-mode-hook))

(defun exit-scheme-interaction-mode ()
  "Take buffer out of scheme interaction mode"
  (interactive)
  (if (not (eq major-mode 'scheme-interaction-mode))
      (error "Buffer not in scheme interaction mode"))
  (let ((previous-state xscheme-previous-process-state))
    (funcall xscheme-previous-mode)
    (let ((process (get-buffer-process (current-buffer))))
      (if process
	  (progn
	    (if (eq (process-filter process) 'xscheme-process-filter)
		(set-process-filter process (car previous-state)))
	    (if (eq (process-sentinel process) 'xscheme-process-sentinel)
		(set-process-sentinel process (cdr previous-state))))))))	

(defun scheme-interaction-mode-initialize ()
  (use-local-map scheme-interaction-mode-map)
  (setq major-mode 'scheme-interaction-mode)
  (setq mode-name "Scheme Interaction"))

(defun scheme-interaction-mode-commands (keymap)
  (define-key keymap "\C-c\C-m" 'xscheme-send-current-line)
  (define-key keymap "\C-c\C-p" 'xscheme-send-proceed)
  (define-key keymap "\C-c\C-y" 'xscheme-yank)
  (define-key keymap "\ep" 'xscheme-yank-pop)
  (define-key keymap "\en" 'xscheme-yank-push))

(defvar scheme-interaction-mode-map nil)
(if (not scheme-interaction-mode-map)
    (progn
      (setq scheme-interaction-mode-map (make-keymap))
      (scheme-mode-commands scheme-interaction-mode-map)
      (xscheme-interrupt-commands scheme-interaction-mode-map)
      (xscheme-evaluation-commands scheme-interaction-mode-map)
      (scheme-interaction-mode-commands scheme-interaction-mode-map)))

(defun xscheme-enter-interaction-mode ()
  (save-excursion
    (set-buffer (xscheme-process-buffer))
    (if (not (eq major-mode 'scheme-interaction-mode))
	(if (eq major-mode 'scheme-debugger-mode)
	    (scheme-interaction-mode-initialize)
	    (scheme-interaction-mode t)))))

(fset 'advertised-xscheme-send-previous-expression
      'xscheme-send-previous-expression)

;;;; Debugger Mode

(defun scheme-debugger-mode ()
  "Major mode for executing the Scheme debugger.
Like  scheme-mode  except that the evaluation commands
are disabled, and characters that would normally be self inserting are
sent to the Scheme process instead.  Typing ?  will show you which
characters perform useful functions.

Commands:
\\{scheme-debugger-mode-map}"
  (error "Illegal entry to scheme-debugger-mode"))

(defun scheme-debugger-mode-initialize ()
  (use-local-map scheme-debugger-mode-map)
  (setq major-mode 'scheme-debugger-mode)
  (setq mode-name "Scheme Debugger"))

(defun scheme-debugger-mode-commands (keymap)
  (let ((char ? ))
    (while (< char 127)
      (define-key keymap (char-to-string char) 'scheme-debugger-self-insert)
      (setq char (1+ char)))))

(defvar scheme-debugger-mode-map nil)
(if (not scheme-debugger-mode-map)
    (progn
      (setq scheme-debugger-mode-map (make-keymap))
      (scheme-mode-commands scheme-debugger-mode-map)
      (xscheme-interrupt-commands scheme-debugger-mode-map)
      (scheme-debugger-mode-commands scheme-debugger-mode-map)))

(defun scheme-debugger-self-insert ()
  "Transmit this character to the Scheme process."
  (interactive)
  (xscheme-send-char last-command-char))

(defun xscheme-enter-debugger-mode (prompt-string)
  (save-excursion
    (set-buffer (xscheme-process-buffer))
    (if (not (eq major-mode 'scheme-debugger-mode))
	(progn
	  (if (not (eq major-mode 'scheme-interaction-mode))
	      (scheme-interaction-mode t))
	  (scheme-debugger-mode-initialize)))))

(defun xscheme-debugger-mode-p ()
  (let ((buffer (xscheme-process-buffer)))
    (and buffer
	 (save-excursion
	   (set-buffer buffer)
	   (eq major-mode 'scheme-debugger-mode)))))

;;;; Evaluation Commands

(defun xscheme-send-string (&rest strings)
  "Send the string arguments to the Scheme process.
The strings are concatenated and terminated by a newline."
  (cond ((not (xscheme-process-running-p))
	 (if (yes-or-no-p "The Scheme process has died.  Reset it? ")
	     (progn
	       (reset-scheme)
	       (xscheme-wait-for-process)
	       (xscheme-send-string-1 strings))))
	((xscheme-debugger-mode-p) (error "No sends allowed in debugger mode"))
	((and (not xscheme-allow-pipelined-evaluation)
	      xscheme-running-p)
	 (error "No sends allowed while Scheme running"))
	(t (xscheme-send-string-1 strings))))

(defun xscheme-send-string-1 (strings)
  (let ((string (apply 'concat strings)))
    (xscheme-send-string-2 string)
    (if (eq major-mode 'scheme-interaction-mode)
	(xscheme-insert-expression string))))

(defun xscheme-send-string-2 (string)
  (let ((process (get-process xscheme-process-name)))
    (process-send-string process (concat string "\n"))
    (if (xscheme-process-buffer-current-p)
	(set-marker (process-mark process) (point)))))

(defun xscheme-select-process-buffer ()
  "Select the Scheme process buffer and move to its output point."
  (interactive)
  (let ((process (or (get-process xscheme-process-name)
		     (error "No scheme process"))))
    (let ((buffer (or (process-buffer process) (error "No process buffer"))))
      (let ((window (get-buffer-window buffer)))
	(if window
	    (select-window window)
	    (switch-to-buffer buffer))
	(goto-char (process-mark process))))))

;;;; Scheme expressions ring

(defun xscheme-insert-expression (string)
  (setq xscheme-expressions-ring (cons string xscheme-expressions-ring))
  (if (> (length xscheme-expressions-ring) xscheme-expressions-ring-max)
      (setcdr (nthcdr (1- xscheme-expressions-ring-max) xscheme-expressions-ring) nil))
  (setq xscheme-expressions-ring-yank-pointer xscheme-expressions-ring))

(defun xscheme-rotate-yank-pointer (arg)
  "Rotate the yanking point in the kill ring."
  (interactive "p")
  (let ((length (length xscheme-expressions-ring)))
    (if (zerop length)
	(error "Scheme expression ring is empty")
      (setq xscheme-expressions-ring-yank-pointer
	    (let ((index (% (+ arg (- length (length xscheme-expressions-ring-yank-pointer)))
			    length)))
	    (nthcdr (if (< index 0)
			(+ index length)
		      index)
		    xscheme-expressions-ring))))))

(defun xscheme-yank (&optional arg)
  "Insert the most recent expression at point.
With just C-U as argument, same but put point in front (and mark at end).
With argument n, reinsert the nth most recently sent expression.
See also the commands \\[xscheme-yank-pop] and \\[xscheme-yank-push]."
  (interactive "*P")
  (xscheme-rotate-yank-pointer (if (listp arg) 0
				 (if (eq arg '-) -1
				   (1- arg))))
  (push-mark (point))
  (insert (car xscheme-expressions-ring-yank-pointer))
  (if (consp arg)
      (exchange-point-and-mark)))

;; Old name, to avoid errors in users' init files.

(fset 'xscheme-yank-previous-send
      'xscheme-yank)

(defun xscheme-yank-pop (arg)
  "Insert or replace a just-yanked expression with an older expression.
If the previous command was not a yank, it yanks.
Otherwise, the region contains a stretch of reinserted
expression.  yank-pop deletes that text and inserts in its
place a different expression.

With no argument, the next older expression is inserted.
With argument n, the n'th older expression is inserted.
If n is negative, this is a more recent expression.

The sequence of expressions wraps around, so that after the oldest one
comes the newest one."
  (interactive "*p")
  (setq this-command 'xscheme-yank)
  (if (not (eq last-command 'xscheme-yank))
      (progn
	(xscheme-yank)
	(setq arg (- arg 1))))
  (if (not (= arg 0))
      (let ((before (< (point) (mark t))))
	(delete-region (point) (mark t))
	(xscheme-rotate-yank-pointer arg)
	(set-mark (point))
	(insert (car xscheme-expressions-ring-yank-pointer))
	(if before (exchange-point-and-mark)))))

(defun xscheme-yank-push (arg)
  "Insert or replace a just-yanked expression with a more recent expression.
If the previous command was not a yank, it yanks.
Otherwise, the region contains a stretch of reinserted
expression.  yank-pop deletes that text and inserts in its
place a different expression.

With no argument, the next more recent expression is inserted.
With argument n, the n'th more recent expression is inserted.
If n is negative, a less recent expression is used.

The sequence of expressions wraps around, so that after the oldest one
comes the newest one."
  (interactive "*p")
  (xscheme-yank-pop (- 0 arg)))

(defun xscheme-send-region (start end)
  "Send the current region to the Scheme process.
The region is sent terminated by a newline."
  (interactive "r")
  (if (xscheme-process-buffer-current-p)
      (progn (goto-char end)
	     (set-marker (process-mark (get-process xscheme-process-name))
			 end)))
  (xscheme-send-string (buffer-substring start end)))

(defun xscheme-send-definition ()
  "Send the current definition to the Scheme process.
If the current line begins with a non-whitespace character,
parse an expression from the beginning of the line and send that instead."
  (interactive)
  (let ((start nil) (end nil))
    (save-excursion
      (end-of-defun)
      (setq end (point))
      (if (re-search-backward "^\\s(" nil t)
	  (setq start (point))
	  (error "Can't find definition")))
    (xscheme-send-region start end)))

(defun xscheme-send-next-expression ()
  "Send the expression to the right of `point' to the Scheme process."
  (interactive)
  (let ((start (point)))
    (xscheme-send-region start (save-excursion (forward-sexp) (point)))))

(defun xscheme-send-previous-expression ()
  "Send the expression to the left of `point' to the Scheme process."
  (interactive)
  (let ((end (point)))
    (xscheme-send-region (save-excursion (backward-sexp) (point)) end)))

(defun xscheme-send-current-line ()
  "Send the current line to the Scheme process.
Useful for working with debugging Scheme under adb."
  (interactive)
  (let ((line
	 (save-excursion
	   (beginning-of-line)
	   (let ((start (point)))
	     (end-of-line)
	     (buffer-substring start (point))))))
    (end-of-line)
    (insert ?\n)
    (xscheme-send-string-2 line)))

(defun xscheme-send-buffer ()
  "Send the current buffer to the Scheme process."
  (interactive)
  (if (xscheme-process-buffer-current-p)
      (error "Not allowed to send this buffer's contents to Scheme"))
  (xscheme-send-region (point-min) (point-max)))

(defun xscheme-send-char (char)
  "Prompt for a character and send it to the Scheme process."
  (interactive "cCharacter to send: ")
  (process-send-string xscheme-process-name (char-to-string char)))

;;;; Interrupts

(defun xscheme-send-breakpoint-interrupt ()
  "Cause the Scheme process to enter a breakpoint."
  (interactive)
  (xscheme-send-interrupt ?b nil))

(defun xscheme-send-proceed ()
  "Cause the Scheme process to proceed from a breakpoint."
  (interactive)
  (process-send-string xscheme-process-name "(proceed)\n"))

(defun buffer-local-value-cell (buffer name)
  (let ((pair (assq name (buffer-local-variables (get-buffer buffer)))))
    (if (not pair)
	(error "buffer-local-value-cell: Not bound")
      pair)))

(defun xscheme-send-control-g-interrupt ()
  "Cause the Scheme processor to halt and flush input.
Control returns to the top level rep loop."
  (interactive)
  (let* ((inhibit-quit t)
	 (vcell (buffer-local-value-cell xscheme-buffer-name
					 'xscheme-control-g-disabled-p)))
    (cond ((not xscheme-control-g-synchronization-p)
	   (interrupt-process xscheme-process-name))
	  ((cdr vcell)
	   (message "Relax..."))
	  (t
	   (rplacd vcell t)
	   (message "Sending C-G interrupt to Scheme...")
	   (interrupt-process xscheme-process-name)
	   (process-send-string xscheme-process-name (char-to-string 0))))))

(defun xscheme-send-control-u-interrupt ()
  "Cause the Scheme process to halt, returning to previous rep loop."
  (interactive)
  (xscheme-send-interrupt ?u t))

(defun xscheme-send-control-x-interrupt ()
  "Cause the Scheme process to halt, returning to current rep loop."
  (interactive)
  (xscheme-send-interrupt ?x t))

;;; This doesn't really work right -- Scheme just gobbles the first
;;; character in the input.  There is no way for us to guarantee that
;;; the argument to this procedure is the first char unless we put
;;; some kind of marker in the input stream.

(defun xscheme-send-interrupt (char mark-p)
  "Send a ^A type interrupt to the Scheme process."
  (interactive "cInterrupt character to send: ")
  (quit-process xscheme-process-name)
  (process-send-string xscheme-process-name (char-to-string char))
  (if (and mark-p xscheme-control-g-synchronization-p)
      (process-send-string xscheme-process-name (char-to-string 0))))

;;;; Internal Variables

(defvar xscheme-process-command-line nil
  "Command used to start the most recent Scheme process.")

(defvar xscheme-expressions-ring-max 30
  "*Maximum length of Scheme expressions ring.")

(defvar xscheme-expressions-ring nil
  "List of expressions recently transmitted to the Scheme process.")

(defvar xscheme-expressions-ring-yank-pointer nil
  "The tail of the Scheme expressions ring whose car is the last thing yanked.")

(defvar xscheme-process-filter-state 'idle
  "State of scheme process escape reader state machine:
idle                   waiting for an escape sequence
reading-type           received an altmode but nothing else
reading-string         reading prompt string")

(defvar xscheme-running-p nil
  "This variable, if nil, indicates that the scheme process is
waiting for input.  Otherwise, it is busy evaluating something.")

(defconst xscheme-control-g-synchronization-p t
  "If non-nil, insert markers in the scheme input stream to indicate when
control-g interrupts were signalled.  Do not allow more control-g's to be
signalled until the scheme process acknowledges receipt.")

(defvar xscheme-control-g-disabled-p nil
  "This variable, if non-nil, indicates that a control-g is being processed
by the scheme process, so additional control-g's are to be ignored.")

(defvar xscheme-allow-output-p t
  "This variable, if nil, prevents output from the scheme process
from being inserted into the process-buffer.")

(defvar xscheme-prompt ""
  "The current scheme prompt string.")

(defvar xscheme-string-accumulator ""
  "Accumulator for the string being received from the scheme process.")

(defvar xscheme-string-receiver nil
  "Procedure to send the string argument from the scheme process.")

(defvar xscheme-start-hook nil
  "If non-nil, a procedure to call when the Scheme process is started.
When called, the current buffer will be the Scheme process-buffer.")

(defvar xscheme-runlight "")
(defvar xscheme-runlight-string nil)
(defvar xscheme-mode-string nil)
(setq-default scheme-mode-line-process
	      '("" xscheme-runlight))

(mapcar 'make-variable-buffer-local
	'(xscheme-expressions-ring
	  xscheme-expressions-ring-yank-pointer
	  xscheme-process-filter-state
	  xscheme-running-p
	  xscheme-control-g-disabled-p
	  xscheme-allow-output-p
	  xscheme-prompt
	  xscheme-string-accumulator
	  xscheme-mode-string
	  scheme-mode-line-process))

;;;; Basic Process Control

(defun xscheme-start-process (command-line the-process the-buffer)
  (let ((buffer (get-buffer-create the-buffer)))
    (let ((process (get-buffer-process buffer)))
      (save-excursion
	(set-buffer buffer)
	(if (and process (memq (process-status process) '(run stop)))
	    (set-marker (process-mark process) (point-max))
	    (progn (if process (delete-process process))
		   (goto-char (point-max))
		   (scheme-interaction-mode nil)
		   (setq xscheme-process-name the-process)
		   (if (bobp)
		       (insert-before-markers
			(substitute-command-keys xscheme-startup-message)))
		   (setq process
			 (let ((process-connection-type nil))
			   (apply 'start-process
				  (cons the-process
					(cons buffer
					      (xscheme-parse-command-line
					       command-line))))))
		   (if (not (equal (process-name process) the-process))
		       (setq xscheme-process-name (process-name process)))
		   (if (not (equal (buffer-name buffer) the-buffer))
		       (setq xscheme-buffer-name (buffer-name buffer)))
		   (message "Starting process %s in buffer %s"
			    xscheme-process-name
			    xscheme-buffer-name)
		   (set-marker (process-mark process) (point-max))
		   (xscheme-process-filter-initialize t)
		   (xscheme-modeline-initialize xscheme-buffer-name)
		   (set-process-sentinel process 'xscheme-process-sentinel)
		   (set-process-filter process 'xscheme-process-filter)
		   (run-hooks 'xscheme-start-hook)))))
    buffer))

(defun xscheme-parse-command-line (string)
  (setq string (substitute-in-file-name string))
  (let ((start 0)
	(result '()))
    (while start
      (let ((index (string-match "[ \t]" string start)))
	(setq start
	      (cond ((not index)
		     (setq result
			   (cons (substring string start)
				 result))
		     nil)
		    ((= index start)
		     (string-match "[^ \t]" string start))
		    (t
		     (setq result
			   (cons (substring string start index)
				 result))
		     (1+ index))))))
    (nreverse result)))

(defun xscheme-wait-for-process ()
  (sleep-for 2)
  (while xscheme-running-p
    (sleep-for 1)))

(defun xscheme-process-running-p ()
  "True iff there is a Scheme process whose status is `run'."
  (let ((process (get-process xscheme-process-name)))
    (and process
	 (eq (process-status process) 'run))))

(defun xscheme-process-buffer ()
  (let ((process (get-process xscheme-process-name)))
    (and process (process-buffer process))))

(defun xscheme-process-buffer-window ()
  (let ((buffer (xscheme-process-buffer)))
    (and buffer (get-buffer-window buffer))))

(defun xscheme-process-buffer-current-p ()
  "True iff the current buffer is the Scheme process buffer."
  (eq (xscheme-process-buffer) (current-buffer)))

;;;; Process Filter

(defun xscheme-process-sentinel (proc reason)
  (let* ((buffer (process-buffer proc))
	 (name (buffer-name buffer)))
    (save-excursion
      (set-buffer buffer)
      (xscheme-process-filter-initialize (eq reason 'run))
      (if (not (eq reason 'run))
	(progn
	  (setq scheme-mode-line-process "")
	  (setq xscheme-mode-string "no process")
	  (if (equal name (default-value 'xscheme-buffer-name))
	      (setq-default xscheme-runlight ""))))
      (if (and (not (memq reason '(run stop)))
	       xscheme-signal-death-message)
	  (progn (beep)
		 (message
"The Scheme process has died!  Do M-x reset-scheme to restart it"))))))

(defun xscheme-process-filter-initialize (running-p)
  (setq xscheme-process-filter-state 'idle)
  (setq xscheme-running-p running-p)
  (setq xscheme-control-g-disabled-p nil)
  (setq xscheme-allow-output-p t)
  (setq xscheme-prompt "")
  (if running-p
      (let ((name (buffer-name (current-buffer))))
	(setq scheme-mode-line-process '(": " xscheme-runlight-string))
	(xscheme-modeline-initialize name)
	(if (equal name (default-value 'xscheme-buffer-name))
	    (setq-default xscheme-runlight default-xscheme-runlight))))
  (if (or (eq xscheme-runlight default-xscheme-runlight)
	  (equal xscheme-runlight ""))
      (setq xscheme-runlight (list ": " 'xscheme-buffer-name ": " "?")))
  (rplaca (nthcdr 3 xscheme-runlight)
	  (if running-p "?" "no process")))

(defun xscheme-process-filter (proc string)
  (save-excursion
    (set-buffer (process-buffer proc))
    (let ((xscheme-filter-input string))
      (while xscheme-filter-input
	(cond ((eq xscheme-process-filter-state 'idle)
	       (let ((start (string-match "\e" xscheme-filter-input)))
		 (if start
		     (progn
		       (xscheme-process-filter-output
			(substring xscheme-filter-input 0 start))
		       (setq xscheme-filter-input
			     (substring xscheme-filter-input (1+ start)))
		       (setq xscheme-process-filter-state 'reading-type))
		   (let ((string xscheme-filter-input))
		     (setq xscheme-filter-input nil)
		     (xscheme-process-filter-output string)))))
	      ((eq xscheme-process-filter-state 'reading-type)
	       (if (zerop (length xscheme-filter-input))
		   (setq xscheme-filter-input nil)
		 (let ((char (aref xscheme-filter-input 0)))
		   (setq xscheme-filter-input
			 (substring xscheme-filter-input 1))
		   (let ((entry (assoc char xscheme-process-filter-alist)))
		     (if entry
			 (funcall (nth 2 entry) (nth 1 entry))
		       (progn
			 (xscheme-process-filter-output ?\e char)
			 (setq xscheme-process-filter-state 'idle)))))))
	      ((eq xscheme-process-filter-state 'reading-string)
	       (let ((start (string-match "\e" xscheme-filter-input)))
		 (if start
		     (let ((string
			    (concat xscheme-string-accumulator
				    (substring xscheme-filter-input 0 start))))
		       (setq xscheme-filter-input
			     (substring xscheme-filter-input (1+ start)))
		       (setq xscheme-process-filter-state 'idle)
		       (funcall xscheme-string-receiver string))
		   (progn
		     (setq xscheme-string-accumulator
			   (concat xscheme-string-accumulator
				   xscheme-filter-input))
		     (setq xscheme-filter-input nil)))))
	      (t
	       (error "Scheme process filter -- bad state")))))))

;;;; Process Filter Output

(defun xscheme-process-filter-output (&rest args)
  (if xscheme-allow-output-p
      (let ((string (apply 'concat args)))
	(save-excursion
	  (xscheme-goto-output-point)
	  (while (string-match "\\(\007\\|\f\\)" string)
	    (let ((start (match-beginning 0))
		  (end (match-end 0)))
	      (insert-before-markers (substring string 0 start))
	      (if (= ?\f (aref string start))
		  (progn
		    (if (not (bolp))
			(insert-before-markers ?\n))
		    (insert-before-markers ?\f))
		  (beep))
	      (setq string (substring string (1+ start)))))
	  (insert-before-markers string)))))

(defun xscheme-guarantee-newlines (n)
  (if xscheme-allow-output-p
      (save-excursion
	(xscheme-goto-output-point)
	(let ((stop nil))
	  (while (and (not stop)
		      (bolp))
	    (setq n (1- n))
	    (if (bobp)
		(setq stop t)
		(backward-char))))
	(xscheme-goto-output-point)
	(while (> n 0)
	  (insert-before-markers ?\n)
	  (setq n (1- n))))))

(defun xscheme-goto-output-point ()
  (let ((process (get-process xscheme-process-name)))
    (set-buffer (process-buffer process))
    (goto-char (process-mark process))))

(defun xscheme-modeline-initialize (name)
  (setq xscheme-runlight-string "")
  (if (equal name (default-value 'xscheme-buffer-name))
      (setq-default xscheme-runlight-string ""))
  (setq xscheme-mode-string "")
  (setq mode-line-buffer-identification
	(list (concat name ": ")
	      'xscheme-mode-string)))

(defun xscheme-set-runlight (runlight)
  (setq xscheme-runlight-string runlight)
  (if (equal (buffer-name (current-buffer))
	     (default-value 'xscheme-buffer-name))
      (setq-default xscheme-runlight-string runlight))
  (rplaca (nthcdr 3 xscheme-runlight) runlight)
  (xscheme-modeline-redisplay))

(defun xscheme-modeline-redisplay ()
  (save-excursion (set-buffer (other-buffer)))
  (set-buffer-modified-p (buffer-modified-p))
  (sit-for 0))

;;;; Process Filter Operations

(defvar xscheme-process-filter-alist
  '((?D xscheme-enter-debugger-mode
	xscheme-process-filter:string-action)
    (?E xscheme-eval
	xscheme-process-filter:string-action)
    (?P xscheme-set-prompt-variable
	xscheme-process-filter:string-action)
    (?R xscheme-enter-interaction-mode
	xscheme-process-filter:simple-action)
    (?b xscheme-start-gc
	xscheme-process-filter:simple-action)
    (?e xscheme-finish-gc
	xscheme-process-filter:simple-action)
    (?f xscheme-exit-input-wait
	xscheme-process-filter:simple-action)
    (?g xscheme-enable-control-g
	xscheme-process-filter:simple-action)
    (?i xscheme-prompt-for-expression
	xscheme-process-filter:string-action)
    (?m xscheme-message
	xscheme-process-filter:string-action)
    (?n xscheme-prompt-for-confirmation
	xscheme-process-filter:string-action)
    (?o xscheme-output-goto
	xscheme-process-filter:simple-action)
    (?p xscheme-set-prompt
	xscheme-process-filter:string-action)
    (?s xscheme-enter-input-wait
	xscheme-process-filter:simple-action)
    (?v xscheme-write-value
	xscheme-process-filter:string-action)
    (?w xscheme-cd
	xscheme-process-filter:string-action)
    (?z xscheme-display-process-buffer
	xscheme-process-filter:simple-action)
    (?c xscheme-unsolicited-read-char
	xscheme-process-filter:simple-action))
  "Table used to decide how to handle process filter commands.
Value is a list of entries, each entry is a list of three items.

The first item is the character that the process filter dispatches on.
The second item is the action to be taken, a function.
The third item is the handler for the entry, a function.

When the process filter sees a command whose character matches a
particular entry, it calls the handler with two arguments: the action
and the string containing the rest of the process filter's input
stream.  It is the responsibility of the handler to invoke the action
with the appropriate arguments, and to reenter the process filter with
the remaining input.")

(defun xscheme-process-filter:simple-action (action)
  (setq xscheme-process-filter-state 'idle)
  (funcall action))

(defun xscheme-process-filter:string-action (action)
  (setq xscheme-string-receiver action)
  (setq xscheme-string-accumulator "")
  (setq xscheme-process-filter-state 'reading-string))

(defconst xscheme-runlight:running "run"
  "The character displayed when the Scheme process is running.")

(defconst xscheme-runlight:input "input"
  "The character displayed when the Scheme process is waiting for input.")

(defconst xscheme-runlight:gc "gc"
  "The character displayed when the Scheme process is garbage collecting.")

(defun xscheme-start-gc ()
  (xscheme-set-runlight xscheme-runlight:gc))

(defun xscheme-finish-gc ()
  (xscheme-set-runlight
   (if xscheme-running-p xscheme-runlight:running xscheme-runlight:input)))

(defun xscheme-enter-input-wait ()
  (xscheme-set-runlight xscheme-runlight:input)
  (setq xscheme-control-g-disabled-p nil)
  (setq xscheme-running-p nil))

(defun xscheme-exit-input-wait ()
  (xscheme-set-runlight xscheme-runlight:running)
  (setq xscheme-running-p t))

(defun xscheme-enable-control-g ()
  (setq xscheme-control-g-disabled-p nil))

(defun xscheme-display-process-buffer ()
  (let ((window (or (xscheme-process-buffer-window)
		    (display-buffer (xscheme-process-buffer)))))
    (save-window-excursion
      (select-window window)
      (xscheme-goto-output-point)
      (if (xscheme-debugger-mode-p)
	  (xscheme-enter-interaction-mode)))))

(defun xscheme-unsolicited-read-char ()
  nil)

(defun xscheme-eval (string)
  (eval (car (read-from-string string))))

(defun xscheme-message (string)
  (if (not (zerop (length string)))
      (xscheme-write-message-1 string (format ";%s" string))))

(defun xscheme-write-value (string)
  (if (zerop (length string))
      (xscheme-write-message-1 "(no value)" ";No value")
      (xscheme-write-message-1 string (format ";Value: %s" string))))

(defun xscheme-write-message-1 (message-string output-string)
  (let* ((process (get-process xscheme-process-name))
	 (window (get-buffer-window (process-buffer process))))
    (if (or (not window)
	    (not (pos-visible-in-window-p (process-mark process)
					  window)))
	(message "%s" message-string)))
  (xscheme-guarantee-newlines 1)
  (xscheme-process-filter-output output-string))

(defun xscheme-set-prompt-variable (string)
  (setq xscheme-prompt string))

(defun xscheme-set-prompt (string)
  (setq xscheme-prompt string)
  (xscheme-guarantee-newlines 2)
  (setq xscheme-mode-string (xscheme-coerce-prompt string))
  (xscheme-modeline-redisplay))

(defun xscheme-output-goto ()
  (xscheme-goto-output-point)
  (xscheme-guarantee-newlines 2))

(defun xscheme-coerce-prompt (string)
  (if (string-match "^[0-9]+ \\[[^]]+\\] " string)
      (let ((end (match-end 0)))
	(let ((prompt (substring string end)))
	  (xscheme-process-filter-output prompt)
	  (if (and (> (length prompt) 0)
		   (not (= (aref prompt (- (length prompt) 1)) ? )))
	      (xscheme-process-filter-output " "))
	  (substring string 0 (- end 1))))
      string))

(defun xscheme-cd (directory-string)
  (save-excursion
    (set-buffer (xscheme-process-buffer))
    (cd directory-string)))

(defun xscheme-prompt-for-confirmation (prompt-string)
  (xscheme-send-char (if (y-or-n-p prompt-string) ?y ?n)))

(defun xscheme-prompt-for-expression (prompt-string)
  (xscheme-send-string-2
   (read-from-minibuffer prompt-string nil xscheme-prompt-for-expression-map)))

(defvar xscheme-prompt-for-expression-map nil)
(if (not xscheme-prompt-for-expression-map)
    (progn
      (setq xscheme-prompt-for-expression-map
	    (copy-keymap minibuffer-local-map))
      (substitute-key-definition 'exit-minibuffer
				 'xscheme-prompt-for-expression-exit
				 xscheme-prompt-for-expression-map)))

(defun xscheme-prompt-for-expression-exit ()
  (interactive)
  (if (eq (xscheme-region-expression-p (point-min) (point-max)) 'one)
      (exit-minibuffer)
      (error "input must be a single, complete expression")))

(defun xscheme-region-expression-p (start end)
  (save-excursion
    (let ((old-syntax-table (syntax-table)))
      (unwind-protect
	  (progn
	    (set-syntax-table scheme-mode-syntax-table)
	    (let ((state (parse-partial-sexp start end)))
	      (and (zerop (car state))	;depth = 0
		   (nth 2 state)	;last-sexp exists, i.e. >= 1 sexps
		   (let ((state (parse-partial-sexp start (nth 2 state))))
		     (if (nth 2 state) 'many 'one)))))
	(set-syntax-table old-syntax-table)))))

(provide 'xscheme)
;;; xscheme.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.