aboutsummaryrefslogtreecommitdiff
path: root/gdb/cli/cli-script.c
blob: 8ec5689ebcfdda09f592cd8172a39a69d3c4e921 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
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
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
/* GDB CLI command scripting.

   Copyright (C) 1986-2023 Free Software Foundation, Inc.

   This file is part of GDB.

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

   This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "value.h"
#include <ctype.h>

#include "ui-out.h"
#include "top.h"
#include "ui.h"
#include "breakpoint.h"
#include "tracepoint.h"
#include "cli/cli-cmds.h"
#include "cli/cli-decode.h"
#include "cli/cli-script.h"
#include "cli/cli-style.h"
#include "gdbcmd.h"

#include "extension.h"
#include "interps.h"
#include "compile/compile.h"
#include "gdbsupport/gdb_string_view.h"
#include "python/python.h"
#include "guile/guile.h"

#include <vector>

/* Prototypes for local functions.  */

static enum command_control_type
recurse_read_control_structure
    (read_next_line_ftype read_next_line_func,
     struct command_line *current_cmd,
     gdb::function_view<void (const char *)> validator);

static void do_define_command (const char *comname, int from_tty,
			       const counted_command_line *commands);

static void do_document_command (const char *comname, int from_tty,
				 const counted_command_line *commands);

static const char *read_next_line (std::string &buffer);

/* Level of control structure when reading.  */
static int control_level;

/* Level of control structure when executing.  */
static int command_nest_depth = 1;

/* This is to prevent certain commands being printed twice.  */
static int suppress_next_print_command_trace = 0;

/* Command element for the 'while' command.  */
static cmd_list_element *while_cmd_element = nullptr;

/* Command element for the 'if' command.  */
static cmd_list_element *if_cmd_element = nullptr;

/* Command element for the 'define' command.  */
static cmd_list_element *define_cmd_element = nullptr;

/* Command element for the 'document' command.  */
static cmd_list_element *document_cmd_element = nullptr;

/* Structure for arguments to user defined functions.  */

class user_args
{
public:
  /* Save the command line and store the locations of arguments passed
     to the user defined function.  */
  explicit user_args (const char *line);

  /* Insert the stored user defined arguments into the $arg arguments
     found in LINE.  */
  std::string insert_args (const char *line) const;

private:
  /* Disable copy/assignment.  (Since the elements of A point inside
     COMMAND, copying would need to reconstruct the A vector in the
     new copy.)  */
  user_args (const user_args &) =delete;
  user_args &operator= (const user_args &) =delete;

  /* It is necessary to store a copy of the command line to ensure
     that the arguments are not overwritten before they are used.  */
  std::string m_command_line;

  /* The arguments.  Each element points inside M_COMMAND_LINE.  */
  std::vector<gdb::string_view> m_args;
};

/* The stack of arguments passed to user defined functions.  We need a
   stack because user-defined functions can call other user-defined
   functions.  */
static std::vector<std::unique_ptr<user_args>> user_args_stack;

/* An RAII-base class used to push/pop args on the user args
   stack.  */
struct scoped_user_args_level
{
  /* Parse the command line and push the arguments in the user args
     stack.  */
  explicit scoped_user_args_level (const char *line)
  {
    user_args_stack.emplace_back (new user_args (line));
  }

  /* Pop the current user arguments from the stack.  */
  ~scoped_user_args_level ()
  {
    user_args_stack.pop_back ();
  }
};


/* Return non-zero if TYPE is a multi-line command (i.e., is terminated
   by "end").  */

static int
multi_line_command_p (enum command_control_type type)
{
  switch (type)
    {
    case if_control:
    case while_control:
    case while_stepping_control:
    case commands_control:
    case compile_control:
    case python_control:
    case guile_control:
    case define_control:
    case document_control:
      return 1;
    default:
      return 0;
    }
}

/* Allocate, initialize a new command line structure for one of the
   control commands (if/while).  */

static command_line_up
build_command_line (enum command_control_type type, const char *args)
{
  if (args == NULL || *args == '\0')
    {
      if (type == if_control)
	error (_("if command requires an argument."));
      else if (type == while_control)
	error (_("while command requires an argument."));
      else if (type == define_control)
	error (_("define command requires an argument."));
      else if (type == document_control)
	error (_("document command requires an argument."));
    }
  gdb_assert (args != NULL);

  return command_line_up (new command_line (type, xstrdup (args)));
}

/* Build and return a new command structure for the control commands
   such as "if" and "while".  */

counted_command_line
get_command_line (enum command_control_type type, const char *arg)
{
  /* Allocate and build a new command line structure.  */
  counted_command_line cmd (build_command_line (type, arg).release (),
			    command_lines_deleter ());

  /* Read in the body of this command.  */
  if (recurse_read_control_structure (read_next_line, cmd.get (), 0)
      == invalid_control)
    {
      warning (_("Error reading in canned sequence of commands."));
      return NULL;
    }

  return cmd;
}

/* Recursively print a command (including full control structures).  */

void
print_command_lines (struct ui_out *uiout, struct command_line *cmd,
		     unsigned int depth)
{
  struct command_line *list;

  list = cmd;
  while (list)
    {
      if (depth)
	uiout->spaces (2 * depth);

      /* A simple command, print it and continue.  */
      if (list->control_type == simple_control)
	{
	  uiout->field_string (NULL, list->line);
	  uiout->text ("\n");
	  list = list->next;
	  continue;
	}

      /* loop_continue to jump to the start of a while loop, print it
	 and continue. */
      if (list->control_type == continue_control)
	{
	  uiout->field_string (NULL, "loop_continue");
	  uiout->text ("\n");
	  list = list->next;
	  continue;
	}

      /* loop_break to break out of a while loop, print it and
	 continue.  */
      if (list->control_type == break_control)
	{
	  uiout->field_string (NULL, "loop_break");
	  uiout->text ("\n");
	  list = list->next;
	  continue;
	}

      /* A while command.  Recursively print its subcommands and
	 continue.  */
      if (list->control_type == while_control
	  || list->control_type == while_stepping_control)
	{
	  /* For while-stepping, the line includes the 'while-stepping'
	     token.  See comment in process_next_line for explanation.
	     Here, take care not print 'while-stepping' twice.  */
	  if (list->control_type == while_control)
	    uiout->field_fmt (NULL, "while %s", list->line);
	  else
	    uiout->field_string (NULL, list->line);
	  uiout->text ("\n");
	  print_command_lines (uiout, list->body_list_0.get (), depth + 1);
	  if (depth)
	    uiout->spaces (2 * depth);
	  uiout->field_string (NULL, "end");
	  uiout->text ("\n");
	  list = list->next;
	  continue;
	}

      /* An if command.  Recursively print both arms before
	 continuing.  */
      if (list->control_type == if_control)
	{
	  uiout->field_fmt (NULL, "if %s", list->line);
	  uiout->text ("\n");
	  /* The true arm.  */
	  print_command_lines (uiout, list->body_list_0.get (), depth + 1);

	  /* Show the false arm if it exists.  */
	  if (list->body_list_1 != nullptr)
	    {
	      if (depth)
		uiout->spaces (2 * depth);
	      uiout->field_string (NULL, "else");
	      uiout->text ("\n");
	      print_command_lines (uiout, list->body_list_1.get (), depth + 1);
	    }

	  if (depth)
	    uiout->spaces (2 * depth);
	  uiout->field_string (NULL, "end");
	  uiout->text ("\n");
	  list = list->next;
	  continue;
	}

      /* A commands command.  Print the breakpoint commands and
	 continue.  */
      if (list->control_type == commands_control)
	{
	  if (*(list->line))
	    uiout->field_fmt (NULL, "commands %s", list->line);
	  else
	    uiout->field_string (NULL, "commands");
	  uiout->text ("\n");
	  print_command_lines (uiout, list->body_list_0.get (), depth + 1);
	  if (depth)
	    uiout->spaces (2 * depth);
	  uiout->field_string (NULL, "end");
	  uiout->text ("\n");
	  list = list->next;
	  continue;
	}

      if (list->control_type == python_control)
	{
	  uiout->field_string (NULL, "python");
	  uiout->text ("\n");
	  /* Don't indent python code at all.  */
	  print_command_lines (uiout, list->body_list_0.get (), 0);
	  if (depth)
	    uiout->spaces (2 * depth);
	  uiout->field_string (NULL, "end");
	  uiout->text ("\n");
	  list = list->next;
	  continue;
	}

      if (list->control_type == compile_control)
	{
	  uiout->field_string (NULL, "compile expression");
	  uiout->text ("\n");
	  print_command_lines (uiout, list->body_list_0.get (), 0);
	  if (depth)
	    uiout->spaces (2 * depth);
	  uiout->field_string (NULL, "end");
	  uiout->text ("\n");
	  list = list->next;
	  continue;
	}

      if (list->control_type == guile_control)
	{
	  uiout->field_string (NULL, "guile");
	  uiout->text ("\n");
	  print_command_lines (uiout, list->body_list_0.get (), depth + 1);
	  if (depth)
	    uiout->spaces (2 * depth);
	  uiout->field_string (NULL, "end");
	  uiout->text ("\n");
	  list = list->next;
	  continue;
	}

      /* Ignore illegal command type and try next.  */
      list = list->next;
    }				/* while (list) */
}

/* Handle pre-post hooks.  */

class scoped_restore_hook_in
{
public:

  scoped_restore_hook_in (struct cmd_list_element *c)
    : m_cmd (c)
  {
  }

  ~scoped_restore_hook_in ()
  {
    m_cmd->hook_in = 0;
  }

  scoped_restore_hook_in (const scoped_restore_hook_in &) = delete;
  scoped_restore_hook_in &operator= (const scoped_restore_hook_in &) = delete;

private:

  struct cmd_list_element *m_cmd;
};

void
execute_cmd_pre_hook (struct cmd_list_element *c)
{
  if ((c->hook_pre) && (!c->hook_in))
    {
      scoped_restore_hook_in restore_hook (c);
      c->hook_in = 1; /* Prevent recursive hooking.  */
      execute_user_command (c->hook_pre, nullptr);
    }
}

void
execute_cmd_post_hook (struct cmd_list_element *c)
{
  if ((c->hook_post) && (!c->hook_in))
    {
      scoped_restore_hook_in restore_hook (c);
      c->hook_in = 1; /* Prevent recursive hooking.  */
      execute_user_command (c->hook_post, nullptr);
    }
}

/* See cli-script.h.  */

void
execute_control_commands (struct command_line *cmdlines, int from_tty)
{
  scoped_restore save_async = make_scoped_restore (&current_ui->async, 0);
  scoped_restore save_nesting
    = make_scoped_restore (&command_nest_depth, command_nest_depth + 1);

  while (cmdlines)
    {
      enum command_control_type ret = execute_control_command (cmdlines,
							       from_tty);
      if (ret != simple_control && ret != break_control)
	{
	  warning (_("Error executing canned sequence of commands."));
	  break;
	}
      cmdlines = cmdlines->next;
    }
}

/* See cli-script.h.  */

std::string
execute_control_commands_to_string (struct command_line *commands,
				    int from_tty)
{
  std::string result;

  execute_fn_to_string (result, [&] ()
    {
      execute_control_commands (commands, from_tty);
    }, false);

  return result;
}

void
execute_user_command (struct cmd_list_element *c, const char *args)
{
  counted_command_line cmdlines_copy;

  /* Ensure that the user commands can't be deleted while they are
     executing.  */
  cmdlines_copy = c->user_commands;
  if (cmdlines_copy == 0)
    /* Null command */
    return;
  struct command_line *cmdlines = cmdlines_copy.get ();

  scoped_user_args_level push_user_args (args);

  if (user_args_stack.size () > max_user_call_depth)
    error (_("Max user call depth exceeded -- command aborted."));

  /* Set the instream to nullptr, indicating execution of a
     user-defined function.  */
  scoped_restore restore_instream
    = make_scoped_restore (&current_ui->instream, nullptr);

  execute_control_commands (cmdlines, 0);
}

/* This function is called every time GDB prints a prompt.  It ensures
   that errors and the like do not confuse the command tracing.  */

void
reset_command_nest_depth (void)
{
  command_nest_depth = 1;

  /* Just in case.  */
  suppress_next_print_command_trace = 0;
}

/* Print the command, prefixed with '+' to represent the call depth.
   This is slightly complicated because this function may be called
   from execute_command and execute_control_command.  Unfortunately
   execute_command also prints the top level control commands.
   In these cases execute_command will call execute_control_command
   via while_command or if_command.  Inner levels of 'if' and 'while'
   are dealt with directly.  Therefore we can use these functions
   to determine whether the command has been printed already or not.  */
ATTRIBUTE_PRINTF (1, 2)
void
print_command_trace (const char *fmt, ...)
{
  int i;

  if (suppress_next_print_command_trace)
    {
      suppress_next_print_command_trace = 0;
      return;
    }

  if (!source_verbose && !trace_commands)
    return;

  for (i=0; i < command_nest_depth; i++)
    gdb_printf ("+");

  va_list args;

  va_start (args, fmt);
  gdb_vprintf (fmt, args);
  va_end (args);
  gdb_puts ("\n");
}

/* Helper for execute_control_command.  */

static enum command_control_type
execute_control_command_1 (struct command_line *cmd, int from_tty)
{
  struct command_line *current;
  int loop;
  enum command_control_type ret;

  /* Start by assuming failure, if a problem is detected, the code
     below will simply "break" out of the switch.  */
  ret = invalid_control;

  switch (cmd->control_type)
    {
    case simple_control:
      {
	/* A simple command, execute it and return.  */
	std::string new_line = insert_user_defined_cmd_args (cmd->line);
	execute_command (new_line.c_str (), from_tty);
	ret = cmd->control_type;
	break;
      }

    case continue_control:
      print_command_trace ("loop_continue");

      /* Return for "continue", and "break" so we can either
	 continue the loop at the top, or break out.  */
      ret = cmd->control_type;
      break;

    case break_control:
      print_command_trace ("loop_break");

      /* Return for "continue", and "break" so we can either
	 continue the loop at the top, or break out.  */
      ret = cmd->control_type;
      break;

    case while_control:
      {
	print_command_trace ("while %s", cmd->line);

	/* Parse the loop control expression for the while statement.  */
	std::string new_line = insert_user_defined_cmd_args (cmd->line);
	expression_up expr = parse_expression (new_line.c_str ());

	ret = simple_control;
	loop = 1;

	/* Keep iterating so long as the expression is true.  */
	while (loop == 1)
	  {
	    bool cond_result;

	    QUIT;

	    /* Evaluate the expression.  */
	    {
	      scoped_value_mark mark;
	      value *val = expr->evaluate ();
	      cond_result = value_true (val);
	    }

	    /* If the value is false, then break out of the loop.  */
	    if (!cond_result)
	      break;

	    /* Execute the body of the while statement.  */
	    current = cmd->body_list_0.get ();
	    while (current)
	      {
		scoped_restore save_nesting
		  = make_scoped_restore (&command_nest_depth, command_nest_depth + 1);
		ret = execute_control_command_1 (current, from_tty);

		/* If we got an error, or a "break" command, then stop
		   looping.  */
		if (ret == invalid_control || ret == break_control)
		  {
		    loop = 0;
		    break;
		  }

		/* If we got a "continue" command, then restart the loop
		   at this point.  */
		if (ret == continue_control)
		  break;

		/* Get the next statement.  */
		current = current->next;
	      }
	  }

	/* Reset RET so that we don't recurse the break all the way down.  */
	if (ret == break_control)
	  ret = simple_control;

	break;
      }

    case if_control:
      {
	print_command_trace ("if %s", cmd->line);

	/* Parse the conditional for the if statement.  */
	std::string new_line = insert_user_defined_cmd_args (cmd->line);
	expression_up expr = parse_expression (new_line.c_str ());

	current = NULL;
	ret = simple_control;

	/* Evaluate the conditional.  */
	{
	  scoped_value_mark mark;
	  value *val = expr->evaluate ();

	  /* Choose which arm to take commands from based on the value
	     of the conditional expression.  */
	  if (value_true (val))
	    current = cmd->body_list_0.get ();
	  else if (cmd->body_list_1 != nullptr)
	    current = cmd->body_list_1.get ();
	}

	/* Execute commands in the given arm.  */
	while (current)
	  {
	    scoped_restore save_nesting
	      = make_scoped_restore (&command_nest_depth, command_nest_depth + 1);
	    ret = execute_control_command_1 (current, from_tty);

	    /* If we got an error, get out.  */
	    if (ret != simple_control)
	      break;

	    /* Get the next statement in the body.  */
	    current = current->next;
	  }

	break;
      }

    case commands_control:
      {
	/* Breakpoint commands list, record the commands in the
	   breakpoint's command list and return.  */
	std::string new_line = insert_user_defined_cmd_args (cmd->line);
	ret = commands_from_control_command (new_line.c_str (), cmd);
	break;
      }

    case compile_control:
      eval_compile_command (cmd, NULL, cmd->control_u.compile.scope,
			    cmd->control_u.compile.scope_data);
      ret = simple_control;
      break;

    case define_control:
      print_command_trace ("define %s", cmd->line);
      do_define_command (cmd->line, 0, &cmd->body_list_0);
      ret = simple_control;
      break;

    case document_control:
      print_command_trace ("document %s", cmd->line);
      do_document_command (cmd->line, 0, &cmd->body_list_0);
      ret = simple_control;
      break;

    case python_control:
    case guile_control:
      {
	eval_ext_lang_from_control_command (cmd);
	ret = simple_control;
	break;
      }

    default:
      warning (_("Invalid control type in canned commands structure."));
      break;
    }

  return ret;
}

enum command_control_type
execute_control_command (struct command_line *cmd, int from_tty)
{
  if (!current_uiout->is_mi_like_p ())
    return execute_control_command_1 (cmd, from_tty);

  /* Make sure we use the console uiout.  It's possible that we are executing
     breakpoint commands while running the MI interpreter.  */
  interp *console = interp_lookup (current_ui, INTERP_CONSOLE);
  scoped_restore save_uiout
    = make_scoped_restore (&current_uiout, console->interp_ui_out ());

  return execute_control_command_1 (cmd, from_tty);
}

/* Like execute_control_command, but first set
   suppress_next_print_command_trace.  */

enum command_control_type
execute_control_command_untraced (struct command_line *cmd)
{
  suppress_next_print_command_trace = 1;
  return execute_control_command (cmd);
}


/* "while" command support.  Executes a body of statements while the
   loop condition is nonzero.  */

static void
while_command (const char *arg, int from_tty)
{
  control_level = 1;
  counted_command_line command = get_command_line (while_control, arg);

  if (command == NULL)
    return;

  scoped_restore save_async = make_scoped_restore (&current_ui->async, 0);

  execute_control_command_untraced (command.get ());
}

/* "if" command support.  Execute either the true or false arm depending
   on the value of the if conditional.  */

static void
if_command (const char *arg, int from_tty)
{
  control_level = 1;
  counted_command_line command = get_command_line (if_control, arg);

  if (command == NULL)
    return;

  scoped_restore save_async = make_scoped_restore (&current_ui->async, 0);

  execute_control_command_untraced (command.get ());
}

/* Bind the incoming arguments for a user defined command to $arg0,
   $arg1 ... $argN.  */

user_args::user_args (const char *command_line)
{
  const char *p;

  if (command_line == NULL)
    return;

  m_command_line = command_line;
  p = m_command_line.c_str ();

  while (*p)
    {
      const char *start_arg;
      int squote = 0;
      int dquote = 0;
      int bsquote = 0;

      /* Strip whitespace.  */
      while (*p == ' ' || *p == '\t')
	p++;

      /* P now points to an argument.  */
      start_arg = p;

      /* Get to the end of this argument.  */
      while (*p)
	{
	  if (((*p == ' ' || *p == '\t')) && !squote && !dquote && !bsquote)
	    break;
	  else
	    {
	      if (bsquote)
		bsquote = 0;
	      else if (*p == '\\')
		bsquote = 1;
	      else if (squote)
		{
		  if (*p == '\'')
		    squote = 0;
		}
	      else if (dquote)
		{
		  if (*p == '"')
		    dquote = 0;
		}
	      else
		{
		  if (*p == '\'')
		    squote = 1;
		  else if (*p == '"')
		    dquote = 1;
		}
	      p++;
	    }
	}

      m_args.emplace_back (start_arg, p - start_arg);
    }
}

/* Given character string P, return a point to the first argument
   ($arg), or NULL if P contains no arguments.  */

static const char *
locate_arg (const char *p)
{
  while ((p = strchr (p, '$')))
    {
      if (startswith (p, "$arg")
	  && (isdigit (p[4]) || p[4] == 'c'))
	return p;
      p++;
    }
  return NULL;
}

/* See cli-script.h.  */

std::string
insert_user_defined_cmd_args (const char *line)
{
  /* If we are not in a user-defined command, treat $argc, $arg0, et
     cetera as normal convenience variables.  */
  if (user_args_stack.empty ())
    return line;

  const std::unique_ptr<user_args> &args = user_args_stack.back ();
  return args->insert_args (line);
}

/* Insert the user defined arguments stored in user_args into the $arg
   arguments found in line.  */

std::string
user_args::insert_args (const char *line) const
{
  std::string new_line;
  const char *p;

  while ((p = locate_arg (line)))
    {
      new_line.append (line, p - line);

      if (p[4] == 'c')
	{
	  new_line += std::to_string (m_args.size ());
	  line = p + 5;
	}
      else
	{
	  char *tmp;
	  unsigned long i;

	  errno = 0;
	  i = strtoul (p + 4, &tmp, 10);
	  if ((i == 0 && tmp == p + 4) || errno != 0)
	    line = p + 4;
	  else if (i >= m_args.size ())
	    error (_("Missing argument %ld in user function."), i);
	  else
	    {
	      new_line.append (m_args[i].data (), m_args[i].length ());
	      line = tmp;
	    }
	}
    }
  /* Don't forget the tail.  */
  new_line.append (line);

  return new_line;
}


/* Read next line from stdin.  Passed to read_command_line_1 and
   recurse_read_control_structure whenever we need to read commands
   from stdin.  */

static const char *
read_next_line (std::string &buffer)
{
  struct ui *ui = current_ui;
  char *prompt_ptr, control_prompt[256];
  int i = 0;
  int from_tty = ui->instream == ui->stdin_stream;

  if (control_level >= 254)
    error (_("Control nesting too deep!"));

  /* Set a prompt based on the nesting of the control commands.  */
  if (from_tty
      || (ui->instream == 0 && deprecated_readline_hook != NULL))
    {
      for (i = 0; i < control_level; i++)
	control_prompt[i] = ' ';
      control_prompt[i] = '>';
      control_prompt[i + 1] = '\0';
      prompt_ptr = (char *) &control_prompt[0];
    }
  else
    prompt_ptr = NULL;

  return command_line_input (buffer, prompt_ptr, "commands");
}

/* Given an input line P, skip the command and return a pointer to the
   first argument.  */

static const char *
line_first_arg (const char *p)
{
  const char *first_arg = p + find_command_name_length (p);

  return skip_spaces (first_arg); 
}

/* Process one input line.  If the command is an "end", return such an
   indication to the caller.  If PARSE_COMMANDS is true, strip leading
   whitespace (trailing whitespace is always stripped) in the line,
   attempt to recognize GDB control commands, and also return an
   indication if the command is an "else" or a nop.

   Otherwise, only "end" is recognized.  */

static enum misc_command_type
process_next_line (const char *p, command_line_up *command,
		   int parse_commands,
		   gdb::function_view<void (const char *)> validator)

{
  const char *p_end;
  const char *p_start;
  int not_handled = 0;

  /* Not sure what to do here.  */
  if (p == NULL)
    return end_command;

  /* Strip trailing whitespace.  */
  p_end = p + strlen (p);
  while (p_end > p && (p_end[-1] == ' ' || p_end[-1] == '\t'))
    p_end--;

  p_start = p;
  /* Strip leading whitespace.  */
  while (p_start < p_end && (*p_start == ' ' || *p_start == '\t'))
    p_start++;

  /* 'end' is always recognized, regardless of parse_commands value.
     We also permit whitespace before end and after.  */
  if (p_end - p_start == 3 && startswith (p_start, "end"))
    return end_command;

  if (parse_commands)
    {
      /* Resolve command abbreviations (e.g. 'ws' for 'while-stepping').  */
      const char *cmd_name = p;
      struct cmd_list_element *cmd
	= lookup_cmd_1 (&cmd_name, cmdlist, NULL, NULL, 1);
      cmd_name = skip_spaces (cmd_name);
      bool inline_cmd = *cmd_name != '\0';

      /* If commands are parsed, we skip initial spaces.  Otherwise,
	 which is the case for Python commands and documentation
	 (see the 'document' command), spaces are preserved.  */
      p = p_start;

      /* Blanks and comments don't really do anything, but we need to
	 distinguish them from else, end and other commands which can
	 be executed.  */
      if (p_end == p || p[0] == '#')
	return nop_command;

      /* Is the else clause of an if control structure?  */
      if (p_end - p == 4 && startswith (p, "else"))
	return else_command;

      /* Check for while, if, break, continue, etc and build a new
	 command line structure for them.  */
      if (cmd == while_stepping_cmd_element)
	{
	  /* Because validate_actionline and encode_action lookup
	     command's line as command, we need the line to
	     include 'while-stepping'.

	     For 'ws' alias, the command will have 'ws', not expanded
	     to 'while-stepping'.  This is intentional -- we don't
	     really want frontend to send a command list with 'ws',
	     and next break-info returning command line with
	     'while-stepping'.  This should work, but might cause the
	     breakpoint to be marked as changed while it's actually
	     not.  */
	  *command = build_command_line (while_stepping_control, p);
	}
      else if (cmd == while_cmd_element)
	*command = build_command_line (while_control, line_first_arg (p));
      else if (cmd == if_cmd_element)
	*command = build_command_line (if_control, line_first_arg (p));
      else if (cmd == commands_cmd_element)
	*command = build_command_line (commands_control, line_first_arg (p));
      else if (cmd == define_cmd_element)
	*command = build_command_line (define_control, line_first_arg (p));
      else if (cmd == document_cmd_element)
	*command = build_command_line (document_control, line_first_arg (p));
      else if (cmd == python_cmd_element && !inline_cmd)
	{
	  /* Note that we ignore the inline "python command" form
	     here.  */
	  *command = build_command_line (python_control, "");
	}
      else if (cmd == compile_cmd_element && !inline_cmd)
	{
	  /* Note that we ignore the inline "compile command" form
	     here.  */
	  *command = build_command_line (compile_control, "");
	  (*command)->control_u.compile.scope = COMPILE_I_INVALID_SCOPE;
	}
      else if (cmd == guile_cmd_element && !inline_cmd)
	{
	  /* Note that we ignore the inline "guile command" form here.  */
	  *command = build_command_line (guile_control, "");
	}
      else if (p_end - p == 10 && startswith (p, "loop_break"))
	*command = command_line_up (new command_line (break_control));
      else if (p_end - p == 13 && startswith (p, "loop_continue"))
	*command = command_line_up (new command_line (continue_control));
      else
	not_handled = 1;
    }

  if (!parse_commands || not_handled)
    {
      /* A normal command.  */
      *command = command_line_up (new command_line (simple_control,
						    savestring (p, p_end - p)));
    }

  if (validator)
    validator ((*command)->line);

  /* Nothing special.  */
  return ok_command;
}

/* Recursively read in the control structures and create a
   command_line structure from them.  Use read_next_line_func to
   obtain lines of the command.  */

static enum command_control_type
recurse_read_control_structure (read_next_line_ftype read_next_line_func,
				struct command_line *current_cmd,
				gdb::function_view<void (const char *)> validator)
{
  enum misc_command_type val;
  enum command_control_type ret;
  struct command_line *child_tail;
  counted_command_line *current_body = &current_cmd->body_list_0;
  command_line_up next;

  child_tail = nullptr;

  /* Sanity checks.  */
  if (current_cmd->control_type == simple_control)
    error (_("Recursed on a simple control type."));

  /* Read lines from the input stream and build control structures.  */
  while (1)
    {
      dont_repeat ();

      std::string buffer;
      next = nullptr;
      val = process_next_line (read_next_line_func (buffer), &next,
			       current_cmd->control_type != python_control
			       && current_cmd->control_type != guile_control
			       && current_cmd->control_type != compile_control,
			       validator);

      /* Just skip blanks and comments.  */
      if (val == nop_command)
	continue;

      if (val == end_command)
	{
	  if (multi_line_command_p (current_cmd->control_type))
	    {
	      /* Success reading an entire canned sequence of commands.  */
	      ret = simple_control;
	      break;
	    }
	  else
	    {
	      ret = invalid_control;
	      break;
	    }
	}

      /* Not the end of a control structure.  */
      if (val == else_command)
	{
	  if (current_cmd->control_type == if_control
	      && current_body == &current_cmd->body_list_0)
	    {
	      current_body = &current_cmd->body_list_1;
	      child_tail = nullptr;
	      continue;
	    }
	  else
	    {
	      ret = invalid_control;
	      break;
	    }
	}

      /* Transfer ownership of NEXT to the command's body list.  */
      if (child_tail != nullptr)
	{
	  child_tail->next = next.release ();
	  child_tail = child_tail->next;
	}
      else
	{
	  child_tail = next.get ();
	  *current_body = counted_command_line (next.release (),
						command_lines_deleter ());
	}

      /* If the latest line is another control structure, then recurse
	 on it.  */
      if (multi_line_command_p (child_tail->control_type))
	{
	  control_level++;
	  ret = recurse_read_control_structure (read_next_line_func,
						child_tail,
						validator);
	  control_level--;

	  if (ret != simple_control)
	    break;
	}
    }

  dont_repeat ();

  return ret;
}

/* Read lines from the input stream and accumulate them in a chain of
   struct command_line's, which is then returned.  For input from a
   terminal, the special command "end" is used to mark the end of the
   input, and is not included in the returned chain of commands.

   If PARSE_COMMANDS is true, strip leading whitespace (trailing whitespace
   is always stripped) in the line and attempt to recognize GDB control
   commands.  Otherwise, only "end" is recognized.  */

#define END_MESSAGE "End with a line saying just \"end\"."

counted_command_line
read_command_lines (const char *prompt_arg, int from_tty, int parse_commands,
		    gdb::function_view<void (const char *)> validator)
{
  if (from_tty && current_ui->input_interactive_p ())
    {
      if (deprecated_readline_begin_hook)
	{
	  /* Note - intentional to merge messages with no newline.  */
	  (*deprecated_readline_begin_hook) ("%s  %s\n", prompt_arg,
					     END_MESSAGE);
	}
      else
	printf_unfiltered ("%s\n%s\n", prompt_arg, END_MESSAGE);
    }


  /* Reading commands assumes the CLI behavior, so temporarily
     override the current interpreter with CLI.  */
  counted_command_line head (nullptr, command_lines_deleter ());
  if (current_interp_named_p (INTERP_CONSOLE))
    head = read_command_lines_1 (read_next_line, parse_commands,
				 validator);
  else
    {
      scoped_restore_interp interp_restorer (INTERP_CONSOLE);

      head = read_command_lines_1 (read_next_line, parse_commands,
				   validator);
    }

  if (from_tty && current_ui->input_interactive_p ()
      && deprecated_readline_end_hook)
    {
      (*deprecated_readline_end_hook) ();
    }
  return (head);
}

/* Act the same way as read_command_lines, except that each new line is
   obtained using READ_NEXT_LINE_FUNC.  */

counted_command_line
read_command_lines_1 (read_next_line_ftype read_next_line_func,
		      int parse_commands,
		      gdb::function_view<void (const char *)> validator)
{
  struct command_line *tail;
  counted_command_line head (nullptr, command_lines_deleter ());
  enum command_control_type ret;
  enum misc_command_type val;
  command_line_up next;

  control_level = 0;
  tail = NULL;

  while (1)
    {
      dont_repeat ();

      std::string buffer;
      val = process_next_line (read_next_line_func (buffer), &next, parse_commands,
			       validator);

      /* Ignore blank lines or comments.  */
      if (val == nop_command)
	continue;

      if (val == end_command)
	{
	  ret = simple_control;
	  break;
	}

      if (val != ok_command)
	{
	  ret = invalid_control;
	  break;
	}

      if (multi_line_command_p (next->control_type))
	{
	  control_level++;
	  ret = recurse_read_control_structure (read_next_line_func, next.get (),
						validator);
	  control_level--;

	  if (ret == invalid_control)
	    break;
	}

      /* Transfer ownership of NEXT to the HEAD list.  */
      if (tail)
	{
	  tail->next = next.release ();
	  tail = tail->next;
	}
      else
	{
	  tail = next.get ();
	  head = counted_command_line (next.release (),
				       command_lines_deleter ());
	}
    }

  dont_repeat ();

  if (ret == invalid_control)
    return NULL;

  return head;
}

/* Free a chain of struct command_line's.  */

void
free_command_lines (struct command_line **lptr)
{
  struct command_line *l = *lptr;
  struct command_line *next;

  while (l)
    {
      next = l->next;
      delete l;
      l = next;
    }
  *lptr = NULL;
}

/* Validate that *COMNAME is a valid name for a command.  Return the
   containing command list, in case it starts with a prefix command.
   The prefix must already exist.  *COMNAME is advanced to point after
   any prefix, and a NUL character overwrites the space after the
   prefix.  */

static struct cmd_list_element **
validate_comname (const char **comname)
{
  struct cmd_list_element **list = &cmdlist;
  const char *p, *last_word;

  if (*comname == 0)
    error_no_arg (_("name of command to define"));

  /* Find the last word of the argument.  */
  p = *comname + strlen (*comname);
  while (p > *comname && isspace (p[-1]))
    p--;
  while (p > *comname && !isspace (p[-1]))
    p--;
  last_word = p;

  /* Find the corresponding command list.  */
  if (last_word != *comname)
    {
      struct cmd_list_element *c;

      /* Separate the prefix and the command.  */
      std::string prefix (*comname, last_word - 1);
      const char *tem = prefix.c_str ();

      c = lookup_cmd (&tem, cmdlist, "", NULL, 0, 1);
      if (!c->is_prefix ())
	error (_("\"%s\" is not a prefix command."), prefix.c_str ());

      list = c->subcommands;
      *comname = last_word;
    }

  p = *comname;
  while (*p)
    {
      if (!valid_cmd_char_p (*p))
	error (_("Junk in argument list: \"%s\""), p);
      p++;
    }

  return list;
}

/* This is just a placeholder in the command data structures.  */
static void
user_defined_command (const char *ignore, int from_tty)
{
}

/* Define a user-defined command.  If COMMANDS is NULL, then this is a
   top-level call and the commands will be read using
   read_command_lines.  Otherwise, it is a "define" command in an
   existing command and the commands are provided.  In the
   non-top-level case, various prompts and warnings are disabled.  */

static void
do_define_command (const char *comname, int from_tty,
		   const counted_command_line *commands)
{
  enum cmd_hook_type
    {
      CMD_NO_HOOK = 0,
      CMD_PRE_HOOK,
      CMD_POST_HOOK
    };
  struct cmd_list_element *c, *newc, *hookc = 0, **list;
  const char *comfull;
  int  hook_type      = CMD_NO_HOOK;
  int  hook_name_size = 0;
   
#define	HOOK_STRING	"hook-"
#define	HOOK_LEN 5
#define HOOK_POST_STRING "hookpost-"
#define HOOK_POST_LEN    9

  comfull = comname;
  list = validate_comname (&comname);

  c = lookup_cmd_exact (comname, *list);

  if (c && commands == nullptr)
    {
      int q;

      if (c->theclass == class_user || c->theclass == class_alias)
	{
	  /* if C is a prefix command that was previously defined,
	     tell the user its subcommands will be kept, and ask
	     if ok to redefine the command.  */
	  if (c->is_prefix ())
	    q = (c->user_commands.get () == nullptr
		 || query (_("Keeping subcommands of prefix command \"%s\".\n"
			     "Redefine command \"%s\"? "), c->name, c->name));
	  else
	    q = query (_("Redefine command \"%s\"? "), c->name);
	}
      else
	q = query (_("Really redefine built-in command \"%s\"? "), c->name);
      if (!q)
	error (_("Command \"%s\" not redefined."), c->name);
    }

  /* If this new command is a hook, then mark the command which it
     is hooking.  Note that we allow hooking `help' commands, so that
     we can hook the `stop' pseudo-command.  */

  if (!strncmp (comname, HOOK_STRING, HOOK_LEN))
    {
       hook_type      = CMD_PRE_HOOK;
       hook_name_size = HOOK_LEN;
    }
  else if (!strncmp (comname, HOOK_POST_STRING, HOOK_POST_LEN))
    {
      hook_type      = CMD_POST_HOOK;
      hook_name_size = HOOK_POST_LEN;
    }

  if (hook_type != CMD_NO_HOOK)
    {
      /* Look up cmd it hooks.  */
      hookc = lookup_cmd_exact (comname + hook_name_size, *list,
				/* ignore_help_classes = */ false);
      if (!hookc && commands == nullptr)
	{
	  warning (_("Your new `%s' command does not "
		     "hook any existing command."),
		   comfull);
	  if (!query (_("Proceed? ")))
	    error (_("Not confirmed."));
	}
    }

  comname = xstrdup (comname);

  counted_command_line cmds;
  if (commands == nullptr)
    {
      std::string prompt
	= string_printf ("Type commands for definition of \"%s\".", comfull);
      cmds = read_command_lines (prompt.c_str (), from_tty, 1, 0);
    }
  else
    cmds = *commands;

  {
    struct cmd_list_element **c_subcommands
      = c == nullptr ? nullptr : c->subcommands;

    newc = add_cmd (comname, class_user, user_defined_command,
		    (c != nullptr && c->theclass == class_user)
		    ? c->doc : xstrdup ("User-defined."), list);
    newc->user_commands = std::move (cmds);

    /* If we define or re-define a command that was previously defined
       as a prefix, keep the prefix information.  */
    if (c_subcommands != nullptr)
      {
	newc->subcommands = c_subcommands;
	/* allow_unknown: see explanation in equivalent logic in
	   define_prefix_command ().  */
	newc->allow_unknown = newc->user_commands.get () != nullptr;
    }
  }

  /* If this new command is a hook, then mark both commands as being
     tied.  */
  if (hookc)
    {
      switch (hook_type)
	{
	case CMD_PRE_HOOK:
	  hookc->hook_pre  = newc;  /* Target gets hooked.  */
	  newc->hookee_pre = hookc; /* We are marked as hooking target cmd.  */
	  break;
	case CMD_POST_HOOK:
	  hookc->hook_post  = newc;  /* Target gets hooked.  */
	  newc->hookee_post = hookc; /* We are marked as hooking
					target cmd.  */
	  break;
	default:
	  /* Should never come here as hookc would be 0.  */
	  internal_error (_("bad switch"));
	}
    }
}

static void
define_command (const char *comname, int from_tty)
{
  do_define_command (comname, from_tty, nullptr);
}

/* Document a user-defined command or user defined alias.  If COMMANDS is NULL,
   then this is a top-level call and the document will be read using
   read_command_lines.  Otherwise, it is a "document" command in an existing
   command and the commands are provided.  */
static void
do_document_command (const char *comname, int from_tty,
		     const counted_command_line *commands)
{
  struct cmd_list_element *alias, *prefix_cmd, *c;
  const char *comfull;

  comfull = comname;
  validate_comname (&comname);

  lookup_cmd_composition (comfull, &alias, &prefix_cmd, &c);
  if (c == nullptr)
    error (_("Undefined command: \"%s\"."), comfull);

  if (c->theclass != class_user
      && (alias == nullptr || alias->theclass != class_alias))
    {
      if (alias == nullptr)
	error (_("Command \"%s\" is built-in."), comfull);
      else
	error (_("Alias \"%s\" is built-in."), comfull);
    }

  /* If we found an alias of class_alias, the user is documenting this
     user-defined alias.  */
  if (alias != nullptr)
    c = alias;

  counted_command_line doclines;

  if (commands == nullptr)
    {
      std::string prompt
	= string_printf ("Type documentation for \"%s\".", comfull);
      doclines = read_command_lines (prompt.c_str (), from_tty, 0, 0);
    }
  else
    doclines = *commands;

  if (c->doc_allocated)
    xfree ((char *) c->doc);

  {
    struct command_line *cl1;
    int len = 0;
    char *doc;

    for (cl1 = doclines.get (); cl1; cl1 = cl1->next)
      len += strlen (cl1->line) + 1;

    doc = (char *) xmalloc (len + 1);
    *doc = 0;

    for (cl1 = doclines.get (); cl1; cl1 = cl1->next)
      {
	strcat (doc, cl1->line);
	if (cl1->next)
	  strcat (doc, "\n");
      }

    c->doc = doc;
    c->doc_allocated = 1;
  }
}

static void
document_command (const char *comname, int from_tty)
{
  do_document_command (comname, from_tty, nullptr);
}

/* Implementation of the "define-prefix" command.  */

static void
define_prefix_command (const char *comname, int from_tty)
{
  struct cmd_list_element *c, **list;
  const char *comfull;

  comfull = comname;
  list = validate_comname (&comname);

  c = lookup_cmd_exact (comname, *list);

  if (c != nullptr && c->theclass != class_user)
    error (_("Command \"%s\" is built-in."), comfull);

  if (c != nullptr && c->is_prefix ())
    {
      /* c is already a user defined prefix command.  */
      return;
    }

  /* If the command does not exist at all, create it.  */
  if (c == nullptr)
    {
      comname = xstrdup (comname);
      c = add_cmd (comname, class_user, user_defined_command,
		   xstrdup ("User-defined."), list);
    }

  /* Allocate the c->subcommands, which marks the command as a prefix
     command.  */
  c->subcommands = new struct cmd_list_element*;
  *(c->subcommands) = nullptr;
  /* If the prefix command C is not a command, then it must be followed
     by known subcommands.  Otherwise, if C is also a normal command,
     it can be followed by C args that must not cause a 'subcommand'
     not recognised error, and thus we must allow unknown.  */
  c->allow_unknown = c->user_commands.get () != nullptr;
}


/* Used to implement source_command.  */

void
script_from_file (FILE *stream, const char *file)
{
  if (stream == NULL)
    internal_error (_("called with NULL file pointer!"));

  scoped_restore restore_line_number
    = make_scoped_restore (&source_line_number, 0);
  scoped_restore restore_file
    = make_scoped_restore<std::string, const std::string &> (&source_file_name,
							     file);

  scoped_restore save_async = make_scoped_restore (&current_ui->async, 0);

  try
    {
      read_command_file (stream);
    }
  catch (const gdb_exception_error &e)
    {
      /* Re-throw the error, but with the file name information
	 prepended.  */
      throw_error (e.error,
		   _("%s:%d: Error in sourced command file:\n%s"),
		   source_file_name.c_str (), source_line_number,
		   e.what ());
    }
}

/* Print the definition of user command C to STREAM.  Or, if C is a
   prefix command, show the definitions of all user commands under C
   (recursively).  PREFIX and NAME combined are the name of the
   current command.  */
void
show_user_1 (struct cmd_list_element *c, const char *prefix, const char *name,
	     struct ui_file *stream)
{
  if (cli_user_command_p (c))
    {
      struct command_line *cmdlines = c->user_commands.get ();

      gdb_printf (stream, "User %scommand \"",
		  c->is_prefix () ? "prefix" : "");
      fprintf_styled (stream, title_style.style (), "%s%s",
		      prefix, name);
      gdb_printf (stream, "\":\n");
      if (cmdlines)
	{
	  print_command_lines (current_uiout, cmdlines, 1);
	  gdb_puts ("\n", stream);
	}
    }

  if (c->is_prefix ())
    {
      const std::string prefixname = c->prefixname ();

      for (c = *c->subcommands; c != NULL; c = c->next)
	if (c->theclass == class_user || c->is_prefix ())
	  show_user_1 (c, prefixname.c_str (), c->name, gdb_stdout);
    }

}

void _initialize_cli_script ();
void
_initialize_cli_script ()
{
  struct cmd_list_element *c;

  /* "document", "define" and "define-prefix" use command_completer,
     as this helps the user to either type the command name and/or
     its prefixes.  */
  document_cmd_element = add_com ("document", class_support, document_command,
				  _("\
Document a user-defined command or user-defined alias.\n\
Give command or alias name as argument.  Give documentation on following lines.\n\
End with a line of just \"end\"."));
  set_cmd_completer (document_cmd_element, command_completer);
  define_cmd_element = add_com ("define", class_support, define_command, _("\
Define a new command name.  Command name is argument.\n\
Definition appears on following lines, one command per line.\n\
End with a line of just \"end\".\n\
Use the \"document\" command to give documentation for the new command.\n\
Commands defined in this way may accept an unlimited number of arguments\n\
accessed via $arg0 .. $argN.  $argc tells how many arguments have\n\
been passed."));
  set_cmd_completer (define_cmd_element, command_completer);
  c = add_com ("define-prefix", class_support, define_prefix_command,
	   _("\
Define or mark a command as a user-defined prefix command.\n\
User defined prefix commands can be used as prefix commands for\n\
other user defined commands.\n\
If the command already exists, it is changed to a prefix command."));
  set_cmd_completer (c, command_completer);

  while_cmd_element = add_com ("while", class_support, while_command, _("\
Execute nested commands WHILE the conditional expression is non zero.\n\
The conditional expression must follow the word `while' and must in turn be\n\
followed by a new line.  The nested commands must be entered one per line,\n\
and should be terminated by the word `end'."));

  if_cmd_element = add_com ("if", class_support, if_command, _("\
Execute nested commands once IF the conditional expression is non zero.\n\
The conditional expression must follow the word `if' and must in turn be\n\
followed by a new line.  The nested commands must be entered one per line,\n\
and should be terminated by the word 'else' or `end'.  If an else clause\n\
is used, the same rules apply to its nested commands as to the first ones."));
}