summaryrefslogtreecommitdiff
path: root/proc.c
blob: 02f33edee96d53bccde9880bfbbcc2f607cddc87 (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
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
/**********************************************************************

  proc.c - Proc, Binding, Env

  $Author$
  created at: Wed Jan 17 12:13:14 2007

  Copyright (C) 2004-2007 Koichi Sasada

**********************************************************************/

#include "eval_intern.h"
#include "gc.h"

struct METHOD {
    VALUE oclass;		/* class that holds the method */
    VALUE rclass;		/* class of the receiver */
    VALUE recv;
    ID id, oid;
    NODE *body;
};

VALUE rb_cUnboundMethod;
VALUE rb_cMethod;
VALUE rb_cBinding;
VALUE rb_cProc;

VALUE rb_iseq_parameters(const rb_iseq_t *iseq, int is_proc);

static VALUE bmcall(VALUE, VALUE);
static int method_arity(VALUE);
static VALUE rb_obj_is_method(VALUE m);
static rb_iseq_t *get_method_iseq(VALUE method);

/* Proc */

static void
proc_free(void *ptr)
{
    RUBY_FREE_ENTER("proc");
    if (ptr) {
	ruby_xfree(ptr);
    }
    RUBY_FREE_LEAVE("proc");
}

static void
proc_mark(void *ptr)
{
    rb_proc_t *proc;
    RUBY_MARK_ENTER("proc");
    if (ptr) {
	proc = ptr;
	RUBY_MARK_UNLESS_NULL(proc->envval);
	RUBY_MARK_UNLESS_NULL(proc->blockprocval);
	RUBY_MARK_UNLESS_NULL(proc->block.proc);
	RUBY_MARK_UNLESS_NULL(proc->block.self);
	if (proc->block.iseq && RUBY_VM_IFUNC_P(proc->block.iseq)) {
	    RUBY_MARK_UNLESS_NULL((VALUE)(proc->block.iseq));
	}
    }
    RUBY_MARK_LEAVE("proc");
}

VALUE
rb_proc_alloc(VALUE klass)
{
    VALUE obj;
    rb_proc_t *proc;
    obj = Data_Make_Struct(klass, rb_proc_t, proc_mark, proc_free, proc);
    MEMZERO(proc, rb_proc_t, 1);
    return obj;
}

VALUE
rb_obj_is_proc(VALUE proc)
{
    if (TYPE(proc) == T_DATA &&
	RDATA(proc)->dfree == (RUBY_DATA_FUNC) proc_free) {
	return Qtrue;
    }
    else {
	return Qfalse;
    }
}

static VALUE
proc_dup(VALUE self)
{
    VALUE procval = rb_proc_alloc(rb_cProc);
    rb_proc_t *src, *dst;
    GetProcPtr(self, src);
    GetProcPtr(procval, dst);

    dst->block = src->block;
    dst->block.proc = procval;
    dst->envval = src->envval;
    dst->safe_level = src->safe_level;
    dst->is_lambda = src->is_lambda;

    return procval;
}

static VALUE
proc_clone(VALUE self)
{
    VALUE procval = proc_dup(self);
    CLONESETUP(procval, self);
    return procval;
}

/*
 * call-seq:
 *   prc.lambda? => true or false
 *
 * Returns true for a Proc object which argument handling is rigid.
 * Such procs are typically generated by lambda.
 *
 * A Proc object generated by proc ignore extra arguments.
 *
 *   proc {|a,b| [a,b] }.call(1,2,3)    => [1,2]
 *
 * It provides nil for lacked arguments.
 *
 *   proc {|a,b| [a,b] }.call(1)        => [1,nil]
 *
 * It expand single-array argument.
 *
 *   proc {|a,b| [a,b] }.call([1,2])    => [1,2]
 *
 * A Proc object generated by lambda doesn't have such tricks.
 *
 *   lambda {|a,b| [a,b] }.call(1,2,3)  => ArgumentError
 *   lambda {|a,b| [a,b] }.call(1)      => ArgumentError
 *   lambda {|a,b| [a,b] }.call([1,2])  => ArgumentError
 *
 * Proc#lambda? is a predicate for the tricks.
 * It returns true if no tricks.
 *
 *   lambda {}.lambda?          => true
 *   proc {}.lambda?            => false
 *
 * Proc.new is same as proc.
 *
 *   Proc.new {}.lambda?        => false
 *
 * lambda, proc and Proc.new preserves the tricks of
 * a Proc object given by & argument.
 *
 *   lambda(&lambda {}).lambda?   => true
 *   proc(&lambda {}).lambda?     => true
 *   Proc.new(&lambda {}).lambda? => true
 *
 *   lambda(&proc {}).lambda?   => false
 *   proc(&proc {}).lambda?     => false
 *   Proc.new(&proc {}).lambda? => false
 *
 * A Proc object generated by & argument has the tricks
 *
 *   def n(&b) b.lambda? end
 *   n {}                       => false
 *
 * The & argument preserves the tricks if a Proc object is given
 * by & argument.
 *
 *   n(&lambda {})              => true
 *   n(&proc {})                => false
 *   n(&Proc.new {})            => false
 *
 * A Proc object converted from a method has no tricks.
 *
 *   def m() end
 *   method(:m).to_proc.lambda? => true
 *
 *   n(&method(:m))             => true
 *   n(&method(:m).to_proc)     => true
 *
 * define_method is treated same as method definition.
 * The defined method has no tricks.
 *
 *   class C
 *     define_method(:d) {}
 *   end
 *   C.new.e(1,2)       => ArgumentError
 *   C.new.method(:d).to_proc.lambda?   => true
 *
 * define_method always defines a method without the tricks,
 * even if a non-lambda Proc object is given.
 * This is the only exception which the tricks are not preserved.
 *
 *   class C
 *     define_method(:e, &proc {})
 *   end
 *   C.new.e(1,2)       => ArgumentError
 *   C.new.method(:e).to_proc.lambda?   => true
 *
 * This exception is for a wrapper of define_method.
 * It eases defining a method defining method which defines a usual method which has no tricks.
 *
 *   class << C
 *     def def2(name, &body)
 *       define_method(name, &body)
 *     end
 *   end
 *   class C
 *     def2(:f) {}
 *   end
 *   C.new.f(1,2)       => ArgumentError
 *
 * The wrapper, def2, defines a method which has no tricks.
 *
 */

static VALUE
proc_lambda_p(VALUE procval)
{
    rb_proc_t *proc;
    GetProcPtr(procval, proc);

    return proc->is_lambda ? Qtrue : Qfalse;
}

/* Binding */

static void
binding_free(void *ptr)
{
    rb_binding_t *bind;
    RUBY_FREE_ENTER("binding");
    if (ptr) {
	bind = ptr;
	ruby_xfree(ptr);
    }
    RUBY_FREE_LEAVE("binding");
}

static void
binding_mark(void *ptr)
{
    rb_binding_t *bind;
    RUBY_MARK_ENTER("binding");
    if (ptr) {
	bind = ptr;
	RUBY_MARK_UNLESS_NULL(bind->env);
    }
    RUBY_MARK_LEAVE("binding");
}

static VALUE
binding_alloc(VALUE klass)
{
    VALUE obj;
    rb_binding_t *bind;
    obj = Data_Make_Struct(klass, rb_binding_t, binding_mark, binding_free, bind);
    return obj;
}

static VALUE
binding_dup(VALUE self)
{
    VALUE bindval = binding_alloc(rb_cBinding);
    rb_binding_t *src, *dst;
    GetBindingPtr(self, src);
    GetBindingPtr(bindval, dst);
    dst->env = src->env;
    return bindval;
}

static VALUE
binding_clone(VALUE self)
{
    VALUE bindval = binding_dup(self);
    CLONESETUP(bindval, self);
    return bindval;
}

VALUE
rb_binding_new(void)
{
    rb_thread_t *th = GET_THREAD();
    rb_control_frame_t *cfp = rb_vm_get_ruby_level_next_cfp(th, th->cfp);
    VALUE bindval = binding_alloc(rb_cBinding);
    rb_binding_t *bind;

    if (cfp == 0) {
	rb_raise(rb_eRuntimeError, "Can't create Binding Object on top of Fiber.");
    }

    GetBindingPtr(bindval, bind);
    bind->env = rb_vm_make_env_object(th, cfp);
    return bindval;
}

/*
 *  call-seq:
 *     binding -> a_binding
 *
 *  Returns a +Binding+ object, describing the variable and
 *  method bindings at the point of call. This object can be used when
 *  calling +eval+ to execute the evaluated command in this
 *  environment. Also see the description of class +Binding+.
 *
 *     def getBinding(param)
 *       return binding
 *     end
 *     b = getBinding("hello")
 *     eval("param", b)   #=> "hello"
 */

static VALUE
rb_f_binding(VALUE self)
{
    return rb_binding_new();
}

/*
 *  call-seq:
 *     binding.eval(string [, filename [,lineno]])  => obj
 *
 *  Evaluates the Ruby expression(s) in <em>string</em>, in the
 *  <em>binding</em>'s context.  If the optional <em>filename</em> and
 *  <em>lineno</em> parameters are present, they will be used when
 *  reporting syntax errors.
 *
 *     def getBinding(param)
 *       return binding
 *     end
 *     b = getBinding("hello")
 *     b.eval("param")   #=> "hello"
 */

static VALUE
bind_eval(int argc, VALUE *argv, VALUE bindval)
{
    VALUE args[4];

    rb_scan_args(argc, argv, "12", &args[0], &args[2], &args[3]);
    args[1] = bindval;
    return rb_f_eval(argc+1, args, Qnil /* self will be searched in eval */);
}

static VALUE
proc_new(VALUE klass, int is_lambda)
{
    VALUE procval = Qnil;
    rb_thread_t *th = GET_THREAD();
    rb_control_frame_t *cfp = th->cfp;
    rb_block_t *block;

    if ((GC_GUARDED_PTR_REF(cfp->lfp[0])) != 0 &&
	!RUBY_VM_CLASS_SPECIAL_P(cfp->lfp[0])) {

	block = GC_GUARDED_PTR_REF(cfp->lfp[0]);
    }
    else {
	cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(cfp);

	if ((GC_GUARDED_PTR_REF(cfp->lfp[0])) != 0 &&
	    !RUBY_VM_CLASS_SPECIAL_P(cfp->lfp[0])) {

	    block = GC_GUARDED_PTR_REF(cfp->lfp[0]);

	    if (is_lambda) {
		rb_warn("tried to create Proc object without a block");
	    }
	}
	else {
	    rb_raise(rb_eArgError,
		     "tried to create Proc object without a block");
	}
    }

    procval = block->proc;

    if (procval) {
	if (RBASIC(procval)->klass == klass) {
	    return procval;
	}
	else {
	    VALUE newprocval = proc_dup(procval);
	    RBASIC(newprocval)->klass = klass;
	    return newprocval;
	}
    }

    procval = rb_vm_make_proc(th, block, klass);

    if (is_lambda) {
	rb_proc_t *proc;
	GetProcPtr(procval, proc);
	proc->is_lambda = Qtrue;
    }
    return procval;
}

/*
 *  call-seq:
 *     Proc.new {|...| block } => a_proc
 *     Proc.new                => a_proc
 *
 *  Creates a new <code>Proc</code> object, bound to the current
 *  context. <code>Proc::new</code> may be called without a block only
 *  within a method with an attached block, in which case that block is
 *  converted to the <code>Proc</code> object.
 *
 *     def proc_from
 *       Proc.new
 *     end
 *     proc = proc_from { "hello" }
 *     proc.call   #=> "hello"
 */

static VALUE
rb_proc_s_new(int argc, VALUE *argv, VALUE klass)
{
    VALUE block = proc_new(klass, Qfalse);

    rb_obj_call_init(block, argc, argv);
    return block;
}

/*
 * call-seq:
 *   proc   { |...| block }  => a_proc
 *
 * Equivalent to <code>Proc.new</code>.
 */

VALUE
rb_block_proc(void)
{
    return proc_new(rb_cProc, Qfalse);
}

VALUE
rb_block_lambda(void)
{
    return proc_new(rb_cProc, Qtrue);
}

VALUE
rb_f_lambda(void)
{
    rb_warn("rb_f_lambda() is deprecated; use rb_block_proc() instead");
    return rb_block_lambda();
}

/*
 * call-seq:
 *   lambda { |...| block }  => a_proc
 *
 * Equivalent to <code>Proc.new</code>, except the resulting Proc objects
 * check the number of parameters passed when called.
 */

static VALUE
proc_lambda(void)
{
    return rb_block_lambda();
}

/* CHECKME: are the argument checking semantics correct? */

/*
 *  call-seq:
 *     prc.call(params,...)   => obj
 *     prc[params,...]        => obj
 *     prc.(params,...)       => obj
 *
 *  Invokes the block, setting the block's parameters to the values in
 *  <i>params</i> using something close to method calling semantics.
 *  Generates a warning if multiple values are passed to a proc that
 *  expects just one (previously this silently converted the parameters
 *  to an array).  Note that prc.() invokes prc.call() with the parameters
 *  given.  It's a syntax sugar to hide "call".
 *
 *  For procs created using <code>Kernel.proc</code>, generates an
 *  error if the wrong number of parameters
 *  are passed to a proc with multiple parameters. For procs created using
 *  <code>Proc.new</code>, extra parameters are silently discarded.
 *
 *  Returns the value of the last expression evaluated in the block. See
 *  also <code>Proc#yield</code>.
 *
 *     a_proc = Proc.new {|a, *b| b.collect {|i| i*a }}
 *     a_proc.call(9, 1, 2, 3)   #=> [9, 18, 27]
 *     a_proc[9, 1, 2, 3]        #=> [9, 18, 27]
 *     a_proc = Proc.new {|a,b| a}
 *     a_proc.call(1,2,3)
 *
 *  <em>produces:</em>
 *
 *     prog.rb:5: wrong number of arguments (3 for 2) (ArgumentError)
 *     	from prog.rb:4:in `call'
 *     	from prog.rb:5
 */

/*
 *  call-seq:
 *     prc === obj   => obj
 *
 *  Invokes the block, with <i>obj</i> as the block's parameter.  It is
 *  to allow a proc object to be a target of when clause in the case statement.
 */

static VALUE
proc_call(int argc, VALUE *argv, VALUE procval)
{
    rb_proc_t *proc;
    rb_block_t *blockptr = 0;
    rb_iseq_t *iseq;
    GetProcPtr(procval, proc);

    iseq = proc->block.iseq;
    if (BUILTIN_TYPE(iseq) == T_NODE || iseq->arg_block != -1) {
	if (rb_block_given_p()) {
	    rb_proc_t *proc;
	    VALUE procval;
	    procval = rb_block_proc();
	    GetProcPtr(procval, proc);
	    blockptr = &proc->block;
	}
    }

    return rb_vm_invoke_proc(GET_THREAD(), proc, proc->block.self,
			     argc, argv, blockptr);
}

VALUE
rb_proc_call(VALUE self, VALUE args)
{
    rb_proc_t *proc;
    GetProcPtr(self, proc);
    return rb_vm_invoke_proc(GET_THREAD(), proc, proc->block.self,
			     RARRAY_LEN(args), RARRAY_PTR(args), 0);
}

VALUE
rb_proc_call_with_block(VALUE self, int argc, VALUE *argv, VALUE pass_procval)
{
    rb_proc_t *proc;
    rb_block_t *block = 0;
    GetProcPtr(self, proc);

    if (!NIL_P(pass_procval)) {
	rb_proc_t *pass_proc;
	GetProcPtr(pass_procval, pass_proc);
	block = &pass_proc->block;
    }

    return rb_vm_invoke_proc(GET_THREAD(), proc, proc->block.self,
			     argc, argv, block);
}

/*
 *  call-seq:
 *     prc.arity -> fixnum
 *
 *  Returns the number of arguments that would not be ignored. If the block
 *  is declared to take no arguments, returns 0. If the block is known
 *  to take exactly n arguments, returns n. If the block has optional
 *  arguments, return -n-1, where n is the number of mandatory
 *  arguments. A <code>proc</code> with no argument declarations
 *  is the same a block declaring <code>||</code> as its arguments.
 *
 *     Proc.new {}.arity          #=>  0
 *     Proc.new {||}.arity        #=>  0
 *     Proc.new {|a|}.arity       #=>  1
 *     Proc.new {|a,b|}.arity     #=>  2
 *     Proc.new {|a,b,c|}.arity   #=>  3
 *     Proc.new {|*a|}.arity      #=> -1
 *     Proc.new {|a,*b|}.arity    #=> -2
 *     Proc.new {|a,*b, c|}.arity    #=> -3
 */

static VALUE
proc_arity(VALUE self)
{
    rb_proc_t *proc;
    rb_iseq_t *iseq;
    GetProcPtr(self, proc);
    iseq = proc->block.iseq;
    if (iseq) {
	if (BUILTIN_TYPE(iseq) != T_NODE) {
	    if (iseq->arg_rest < 0) {
		return INT2FIX(iseq->argc);
	    }
	    else {
		return INT2FIX(-(iseq->argc + 1 + iseq->arg_post_len));
	    }
	}
	else {
	    NODE *node = (NODE *)iseq;
	    if (nd_type(node) == NODE_IFUNC && node->nd_cfnc == bmcall) {
		/* method(:foo).to_proc.arity */
		return INT2FIX(method_arity(node->nd_tval));
	    }
	}
    }
    return INT2FIX(-1);
}

int
rb_proc_arity(VALUE proc)
{
    return FIX2INT(proc_arity(proc));
}

static rb_iseq_t *
get_proc_iseq(VALUE self, int *is_proc)
{
    rb_proc_t *proc;
    rb_iseq_t *iseq;

    GetProcPtr(self, proc);
    iseq = proc->block.iseq;
    if (is_proc) *is_proc = !proc->is_lambda;
    if (!RUBY_VM_NORMAL_ISEQ_P(iseq)) {
	NODE *node = (NODE *)iseq;
	iseq = 0;
	if (nd_type(node) == NODE_IFUNC && node->nd_cfnc == bmcall) {
	    /* method(:foo).to_proc */
	    iseq = get_method_iseq(node->nd_tval);
	    if (is_proc) *is_proc = 0;
	}
    }
    return iseq;
}

static VALUE
iseq_location(rb_iseq_t *iseq)
{
    VALUE loc[2];

    if (!iseq) return Qnil;
    loc[0] = iseq->filename;
    if (iseq->insn_info_table) {
	loc[1] = INT2FIX(rb_iseq_first_lineno(iseq));
    }
    else {
	loc[1] = Qnil;
    }
    return rb_ary_new4(2, loc);
}

/*
 * call-seq:
 *    prc.source_location  => [String, Fixnum]
 *
 * returns the ruby source filename and line number containing this proc
 * or nil if this proc was not defined in ruby (i.e. native)
 */

VALUE
rb_proc_location(VALUE self)
{
    return iseq_location(get_proc_iseq(self, 0));
}

static VALUE
unnamed_parameters(int arity)
{
    VALUE a, param = rb_ary_new2((arity < 0) ? -arity : arity);
    int n = (arity < 0) ? ~arity : arity;
    ID req, rest;
    CONST_ID(req, "req");
    a = rb_ary_new3(1, ID2SYM(req));
    OBJ_FREEZE(a);
    for (; n; --n) {
	rb_ary_push(param, a);
    }
    if (arity < 0) {
	CONST_ID(rest, "rest");
	rb_ary_store(param, ~arity, rb_ary_new3(1, ID2SYM(rest)));
    }
    return param;
}

/*
 * call-seq:
 *    proc.parameters  => array
 *
 * returns the parameter information of this proc
 */

static VALUE
rb_proc_parameters(VALUE self)
{
    int is_proc;
    rb_iseq_t *iseq = get_proc_iseq(self, &is_proc);
    if (!iseq) {
	return unnamed_parameters(proc_arity(self));
    }
    return rb_iseq_parameters(iseq, is_proc);
}

/*
 * call-seq:
 *   prc == other_proc   =>  true or false
 *
 * Return <code>true</code> if <i>prc</i> is the same object as
 * <i>other_proc</i>, or if they are both procs with the same body.
 */

static VALUE
proc_eq(VALUE self, VALUE other)
{
    if (self == other) {
	return Qtrue;
    }
    else {
	if (TYPE(other)          == T_DATA &&
	    RDATA(other)->dmark  == proc_mark) {
	    rb_proc_t *p1, *p2;
	    GetProcPtr(self, p1);
	    GetProcPtr(other, p2);
	    if (p1->envval == p2->envval &&
		p1->block.iseq->iseq_size == p2->block.iseq->iseq_size &&
		p1->block.iseq->local_size == p2->block.iseq->local_size &&
		MEMCMP(p1->block.iseq->iseq, p2->block.iseq->iseq, VALUE,
		       p1->block.iseq->iseq_size) == 0) {
		return Qtrue;
	    }
	}
    }
    return Qfalse;
}

/*
 * call-seq:
 *   prc.hash   =>  integer
 *
 * Return hash value corresponding to proc body.
 */

static VALUE
proc_hash(VALUE self)
{
    int hash;
    rb_proc_t *proc;
    GetProcPtr(self, proc);
    hash = (long)proc->block.iseq;
    hash ^= (long)proc->envval;
    hash ^= (long)proc->block.lfp >> 16;
    return INT2FIX(hash);
}

/*
 * call-seq:
 *   prc.to_s   => string
 *
 * Shows the unique identifier for this proc, along with
 * an indication of where the proc was defined.
 */

static VALUE
proc_to_s(VALUE self)
{
    VALUE str = 0;
    rb_proc_t *proc;
    const char *cname = rb_obj_classname(self);
    rb_iseq_t *iseq;
    const char *is_lambda;

    GetProcPtr(self, proc);
    iseq = proc->block.iseq;
    is_lambda = proc->is_lambda ? " (lambda)" : "";

    if (RUBY_VM_NORMAL_ISEQ_P(iseq)) {
	int line_no = 0;

	if (iseq->insn_info_table) {
	    line_no = rb_iseq_first_lineno(iseq);
	}
	str = rb_sprintf("#<%s:%p@%s:%d%s>", cname, (void *)self,
			 RSTRING_PTR(iseq->filename),
			 line_no, is_lambda);
    }
    else {
	str = rb_sprintf("#<%s:%p%s>", cname, (void *)proc->block.iseq,
			 is_lambda);
    }

    if (OBJ_TAINTED(self)) {
	OBJ_TAINT(str);
    }
    return str;
}

/*
 *  call-seq:
 *     prc.to_proc -> prc
 *
 *  Part of the protocol for converting objects to <code>Proc</code>
 *  objects. Instances of class <code>Proc</code> simply return
 *  themselves.
 */

static VALUE
proc_to_proc(VALUE self)
{
    return self;
}

static void
bm_mark(struct METHOD *data)
{
    rb_gc_mark(data->rclass);
    rb_gc_mark(data->oclass);
    rb_gc_mark(data->recv);
    rb_gc_mark((VALUE)data->body);
}

NODE *
rb_method_body(VALUE method)
{
    struct METHOD *data;

    if (TYPE(method) == T_DATA &&
	RDATA(method)->dmark == (RUBY_DATA_FUNC) bm_mark) {
	Data_Get_Struct(method, struct METHOD, data);
	return data->body;
    }
    else {
	return 0;
    }
}

NODE *rb_get_method_body(VALUE klass, ID id, ID *idp);

static VALUE
mnew(VALUE klass, VALUE obj, ID id, VALUE mclass, int scope)
{
    VALUE method;
    NODE *body;
    struct METHOD *data;
    VALUE rclass = klass;
    ID oid = id;

  again:
    if ((body = rb_get_method_body(klass, id, 0)) == 0) {
	rb_print_undef(rclass, oid, 0);
    }
    if (scope && (body->nd_noex & NOEX_MASK) != NOEX_PUBLIC) {
	rb_print_undef(rclass, oid, (body->nd_noex & NOEX_MASK));
    }

    klass = body->nd_clss;
    body = body->nd_body;

    if (nd_type(body) == NODE_ZSUPER) {
	klass = RCLASS_SUPER(klass);
	goto again;
    }

    while (rclass != klass &&
	   (FL_TEST(rclass, FL_SINGLETON) || TYPE(rclass) == T_ICLASS)) {
	rclass = RCLASS_SUPER(rclass);
    }
    if (TYPE(klass) == T_ICLASS)
	klass = RBASIC(klass)->klass;
    method = Data_Make_Struct(mclass, struct METHOD, bm_mark, -1, data);
    data->oclass = klass;
    data->recv = obj;

    data->id = id;
    data->body = body;
    data->rclass = rclass;
    data->oid = oid;
    OBJ_INFECT(method, klass);

    return method;
}


/**********************************************************************
 *
 * Document-class : Method
 *
 *  Method objects are created by <code>Object#method</code>, and are
 *  associated with a particular object (not just with a class). They
 *  may be used to invoke the method within the object, and as a block
 *  associated with an iterator. They may also be unbound from one
 *  object (creating an <code>UnboundMethod</code>) and bound to
 *  another.
 *
 *     class Thing
 *       def square(n)
 *         n*n
 *       end
 *     end
 *     thing = Thing.new
 *     meth  = thing.method(:square)
 *
 *     meth.call(9)                 #=> 81
 *     [ 1, 2, 3 ].collect(&meth)   #=> [1, 4, 9]
 *
 */

/*
 * call-seq:
 *   meth == other_meth  => true or false
 *
 * Two method objects are equal if that are bound to the same
 * object and contain the same body.
 */


static VALUE
method_eq(VALUE method, VALUE other)
{
    struct METHOD *m1, *m2;

    if (TYPE(other) != T_DATA
	|| RDATA(other)->dmark != (RUBY_DATA_FUNC) bm_mark)
	return Qfalse;
    if (CLASS_OF(method) != CLASS_OF(other))
	return Qfalse;

    Data_Get_Struct(method, struct METHOD, m1);
    Data_Get_Struct(other, struct METHOD, m2);

    if (m1->oclass != m2->oclass || m1->rclass != m2->rclass ||
	m1->recv != m2->recv || m1->body != m2->body)
	return Qfalse;

    return Qtrue;
}

/*
 * call-seq:
 *    meth.hash   => integer
 *
 * Return a hash value corresponding to the method object.
 */

static VALUE
method_hash(VALUE method)
{
    struct METHOD *m;
    long hash;

    Data_Get_Struct(method, struct METHOD, m);
    hash = (long)m->oclass;
    hash ^= (long)m->rclass;
    hash ^= (long)m->recv;
    hash ^= (long)m->body;

    return INT2FIX(hash);
}

/*
 *  call-seq:
 *     meth.unbind    => unbound_method
 *
 *  Dissociates <i>meth</i> from it's current receiver. The resulting
 *  <code>UnboundMethod</code> can subsequently be bound to a new object
 *  of the same class (see <code>UnboundMethod</code>).
 */

static VALUE
method_unbind(VALUE obj)
{
    VALUE method;
    struct METHOD *orig, *data;

    Data_Get_Struct(obj, struct METHOD, orig);
    method =
	Data_Make_Struct(rb_cUnboundMethod, struct METHOD, bm_mark, -1, data);
    data->oclass = orig->oclass;
    data->recv = Qundef;
    data->id = orig->id;
    data->body = orig->body;
    data->rclass = orig->rclass;
    data->oid = orig->oid;
    OBJ_INFECT(method, obj);

    return method;
}

/*
 *  call-seq:
 *     meth.receiver    => object
 *
 *  Returns the bound receiver of the method object.
 */

static VALUE
method_receiver(VALUE obj)
{
    struct METHOD *data;

    Data_Get_Struct(obj, struct METHOD, data);
    return data->recv;
}

/*
 *  call-seq:
 *     meth.name    => symbol
 *
 *  Returns the name of the method.
 */

static VALUE
method_name(VALUE obj)
{
    struct METHOD *data;

    Data_Get_Struct(obj, struct METHOD, data);
    return ID2SYM(data->id);
}

/*
 *  call-seq:
 *     meth.owner    => class_or_module
 *
 *  Returns the class or module that defines the method.
 */

static VALUE
method_owner(VALUE obj)
{
    struct METHOD *data;

    Data_Get_Struct(obj, struct METHOD, data);
    return data->oclass;
}

/*
 *  call-seq:
 *     obj.method(sym)    => method
 *
 *  Looks up the named method as a receiver in <i>obj</i>, returning a
 *  <code>Method</code> object (or raising <code>NameError</code>). The
 *  <code>Method</code> object acts as a closure in <i>obj</i>'s object
 *  instance, so instance variables and the value of <code>self</code>
 *  remain available.
 *
 *     class Demo
 *       def initialize(n)
 *         @iv = n
 *       end
 *       def hello()
 *         "Hello, @iv = #{@iv}"
 *       end
 *     end
 *
 *     k = Demo.new(99)
 *     m = k.method(:hello)
 *     m.call   #=> "Hello, @iv = 99"
 *
 *     l = Demo.new('Fred')
 *     m = l.method("hello")
 *     m.call   #=> "Hello, @iv = Fred"
 */

VALUE
rb_obj_method(VALUE obj, VALUE vid)
{
    return mnew(CLASS_OF(obj), obj, rb_to_id(vid), rb_cMethod, Qfalse);
}

VALUE
rb_obj_public_method(VALUE obj, VALUE vid)
{
    return mnew(CLASS_OF(obj), obj, rb_to_id(vid), rb_cMethod, Qtrue);
}

/*
 *  call-seq:
 *     mod.instance_method(symbol)   => unbound_method
 *
 *  Returns an +UnboundMethod+ representing the given
 *  instance method in _mod_.
 *
 *     class Interpreter
 *       def do_a() print "there, "; end
 *       def do_d() print "Hello ";  end
 *       def do_e() print "!\n";     end
 *       def do_v() print "Dave";    end
 *       Dispatcher = {
 *        ?a => instance_method(:do_a),
 *        ?d => instance_method(:do_d),
 *        ?e => instance_method(:do_e),
 *        ?v => instance_method(:do_v)
 *       }
 *       def interpret(string)
 *         string.each_byte {|b| Dispatcher[b].bind(self).call }
 *       end
 *     end
 *
 *
 *     interpreter = Interpreter.new
 *     interpreter.interpret('dave')
 *
 *  <em>produces:</em>
 *
 *     Hello there, Dave!
 */

static VALUE
rb_mod_instance_method(VALUE mod, VALUE vid)
{
    return mnew(mod, Qundef, rb_to_id(vid), rb_cUnboundMethod, Qfalse);
}

static VALUE
rb_mod_public_instance_method(VALUE mod, VALUE vid)
{
    return mnew(mod, Qundef, rb_to_id(vid), rb_cUnboundMethod, Qtrue);
}

/*
 *  call-seq:
 *     define_method(symbol, method)     => new_method
 *     define_method(symbol) { block }   => proc
 *
 *  Defines an instance method in the receiver. The _method_
 *  parameter can be a +Proc+ or +Method+ object.
 *  If a block is specified, it is used as the method body. This block
 *  is evaluated using <code>instance_eval</code>, a point that is
 *  tricky to demonstrate because <code>define_method</code> is private.
 *  (This is why we resort to the +send+ hack in this example.)
 *
 *     class A
 *       def fred
 *         puts "In Fred"
 *       end
 *       def create_method(name, &block)
 *         self.class.send(:define_method, name, &block)
 *       end
 *       define_method(:wilma) { puts "Charge it!" }
 *     end
 *     class B < A
 *       define_method(:barney, instance_method(:fred))
 *     end
 *     a = B.new
 *     a.barney
 *     a.wilma
 *     a.create_method(:betty) { p self }
 *     a.betty
 *
 *  <em>produces:</em>
 *
 *     In Fred
 *     Charge it!
 *     #<B:0x401b39e8>
 */

static VALUE
rb_mod_define_method(int argc, VALUE *argv, VALUE mod)
{
    ID id;
    VALUE body;
    NODE *node;
    int noex = NOEX_PUBLIC;

    if (argc == 1) {
	id = rb_to_id(argv[0]);
	body = rb_block_lambda();
    }
    else if (argc == 2) {
	id = rb_to_id(argv[0]);
	body = argv[1];
	if (!rb_obj_is_method(body) && !rb_obj_is_proc(body)) {
	    rb_raise(rb_eTypeError,
		     "wrong argument type %s (expected Proc/Method)",
		     rb_obj_classname(body));
	}
    }
    else {
	rb_raise(rb_eArgError, "wrong number of arguments (%d for 1)", argc);
    }

    if (RDATA(body)->dmark == (RUBY_DATA_FUNC) bm_mark) {
	struct METHOD *method = (struct METHOD *)DATA_PTR(body);
	VALUE rclass = method->rclass;
	if (rclass != mod) {
	    if (FL_TEST(rclass, FL_SINGLETON)) {
		rb_raise(rb_eTypeError,
			 "can't bind singleton method to a different class");
	    }
	    if (!RTEST(rb_class_inherited_p(mod, rclass))) {
		rb_raise(rb_eTypeError,
			 "bind argument must be a subclass of %s",
			 rb_class2name(rclass));
	    }
	}
	node = method->body;
    }
    else if (rb_obj_is_proc(body)) {
	rb_proc_t *proc;
	body = proc_dup(body);
	GetProcPtr(body, proc);
	if (BUILTIN_TYPE(proc->block.iseq) != T_NODE) {
	    proc->block.iseq->defined_method_id = id;
	    proc->block.iseq->klass = mod;
	    proc->is_lambda = Qtrue;
	    proc->is_from_method = Qtrue;
	}
	node = NEW_BMETHOD(body);
    }
    else {
	/* type error */
	rb_raise(rb_eTypeError, "wrong argument type (expected Proc/Method)");
    }

    /* TODO: visibility */

    rb_add_method(mod, id, node, noex);
    return body;
}

static VALUE
rb_obj_define_method(int argc, VALUE *argv, VALUE obj)
{
    VALUE klass = rb_singleton_class(obj);

    return rb_mod_define_method(argc, argv, klass);
}


/*
 * MISSING: documentation
 */

static VALUE
method_clone(VALUE self)
{
    VALUE clone;
    struct METHOD *orig, *data;

    Data_Get_Struct(self, struct METHOD, orig);
    clone = Data_Make_Struct(CLASS_OF(self), struct METHOD, bm_mark, -1, data);
    CLONESETUP(clone, self);
    *data = *orig;

    return clone;
}

/*
 *  call-seq:
 *     meth.call(args, ...)    => obj
 *     meth[args, ...]         => obj
 *
 *  Invokes the <i>meth</i> with the specified arguments, returning the
 *  method's return value.
 *
 *     m = 12.method("+")
 *     m.call(3)    #=> 15
 *     m.call(20)   #=> 32
 */

VALUE
rb_method_call(int argc, VALUE *argv, VALUE method)
{
    VALUE result = Qnil;	/* OK */
    struct METHOD *data;
    int state;
    volatile int safe = -1;

    Data_Get_Struct(method, struct METHOD, data);
    if (data->recv == Qundef) {
	rb_raise(rb_eTypeError, "can't call unbound method; bind first");
    }
    PUSH_TAG();
    if (OBJ_TAINTED(method)) {
	safe = rb_safe_level();
	if (rb_safe_level() < 4) {
	    rb_set_safe_level_force(4);
	}
    }
    if ((state = EXEC_TAG()) == 0) {
	rb_thread_t *th = GET_THREAD();
	VALUE rb_vm_call(rb_thread_t * th, VALUE klass, VALUE recv, VALUE id, ID oid,
			 int argc, const VALUE *argv, const NODE *body, int nosuper);

	PASS_PASSED_BLOCK_TH(th);
	result = rb_vm_call(th, data->oclass, data->recv, data->id, data->oid,
			    argc, argv, data->body, 0);
    }
    POP_TAG();
    if (safe >= 0)
	rb_set_safe_level_force(safe);
    if (state)
	JUMP_TAG(state);
    return result;
}

/**********************************************************************
 *
 * Document-class: UnboundMethod
 *
 *  Ruby supports two forms of objectified methods. Class
 *  <code>Method</code> is used to represent methods that are associated
 *  with a particular object: these method objects are bound to that
 *  object. Bound method objects for an object can be created using
 *  <code>Object#method</code>.
 *
 *  Ruby also supports unbound methods; methods objects that are not
 *  associated with a particular object. These can be created either by
 *  calling <code>Module#instance_method</code> or by calling
 *  <code>unbind</code> on a bound method object. The result of both of
 *  these is an <code>UnboundMethod</code> object.
 *
 *  Unbound methods can only be called after they are bound to an
 *  object. That object must be be a kind_of? the method's original
 *  class.
 *
 *     class Square
 *       def area
 *         @side * @side
 *       end
 *       def initialize(side)
 *         @side = side
 *       end
 *     end
 *
 *     area_un = Square.instance_method(:area)
 *
 *     s = Square.new(12)
 *     area = area_un.bind(s)
 *     area.call   #=> 144
 *
 *  Unbound methods are a reference to the method at the time it was
 *  objectified: subsequent changes to the underlying class will not
 *  affect the unbound method.
 *
 *     class Test
 *       def test
 *         :original
 *       end
 *     end
 *     um = Test.instance_method(:test)
 *     class Test
 *       def test
 *         :modified
 *       end
 *     end
 *     t = Test.new
 *     t.test            #=> :modified
 *     um.bind(t).call   #=> :original
 *
 */

/*
 *  call-seq:
 *     umeth.bind(obj) -> method
 *
 *  Bind <i>umeth</i> to <i>obj</i>. If <code>Klass</code> was the class
 *  from which <i>umeth</i> was obtained,
 *  <code>obj.kind_of?(Klass)</code> must be true.
 *
 *     class A
 *       def test
 *         puts "In test, class = #{self.class}"
 *       end
 *     end
 *     class B < A
 *     end
 *     class C < B
 *     end
 *
 *
 *     um = B.instance_method(:test)
 *     bm = um.bind(C.new)
 *     bm.call
 *     bm = um.bind(B.new)
 *     bm.call
 *     bm = um.bind(A.new)
 *     bm.call
 *
 *  <em>produces:</em>
 *
 *     In test, class = C
 *     In test, class = B
 *     prog.rb:16:in `bind': bind argument must be an instance of B (TypeError)
 *     	from prog.rb:16
 */

static VALUE
umethod_bind(VALUE method, VALUE recv)
{
    struct METHOD *data, *bound;

    Data_Get_Struct(method, struct METHOD, data);
    if (data->rclass != CLASS_OF(recv)) {
	if (FL_TEST(data->rclass, FL_SINGLETON)) {
	    rb_raise(rb_eTypeError,
		     "singleton method called for a different object");
	}
	if (!rb_obj_is_kind_of(recv, data->rclass)) {
	    rb_raise(rb_eTypeError, "bind argument must be an instance of %s",
		     rb_class2name(data->rclass));
	}
    }

    method = Data_Make_Struct(rb_cMethod, struct METHOD, bm_mark, -1, bound);
    *bound = *data;
    bound->recv = recv;
    bound->rclass = CLASS_OF(recv);

    return method;
}

int
rb_node_arity(NODE* body)
{
    switch (nd_type(body)) {
      case NODE_CFUNC:
	if (body->nd_argc < 0)
	    return -1;
	return body->nd_argc;
      case NODE_ZSUPER:
	return -1;
      case NODE_ATTRSET:
	return 1;
      case NODE_IVAR:
	return 0;
      case NODE_BMETHOD:
	return rb_proc_arity(body->nd_cval);
      case RUBY_VM_METHOD_NODE:
	{
	    rb_iseq_t *iseq;
	    GetISeqPtr((VALUE)body->nd_body, iseq);
	    if (iseq->arg_rest == -1 && iseq->arg_opts == 0) {
		return iseq->argc;
	    }
	    else {
		return -(iseq->argc + 1 + iseq->arg_post_len);
	    }
	}
      default:
	rb_raise(rb_eArgError, "invalid node 0x%x", nd_type(body));
    }
}

/*
 *  call-seq:
 *     meth.arity    => fixnum
 *
 *  Returns an indication of the number of arguments accepted by a
 *  method. Returns a nonnegative integer for methods that take a fixed
 *  number of arguments. For Ruby methods that take a variable number of
 *  arguments, returns -n-1, where n is the number of required
 *  arguments. For methods written in C, returns -1 if the call takes a
 *  variable number of arguments.
 *
 *     class C
 *       def one;    end
 *       def two(a); end
 *       def three(*a);  end
 *       def four(a, b); end
 *       def five(a, b, *c);    end
 *       def six(a, b, *c, &d); end
 *     end
 *     c = C.new
 *     c.method(:one).arity     #=> 0
 *     c.method(:two).arity     #=> 1
 *     c.method(:three).arity   #=> -1
 *     c.method(:four).arity    #=> 2
 *     c.method(:five).arity    #=> -3
 *     c.method(:six).arity     #=> -3
 *
 *     "cat".method(:size).arity      #=> 0
 *     "cat".method(:replace).arity   #=> 1
 *     "cat".method(:squeeze).arity   #=> -1
 *     "cat".method(:count).arity     #=> -1
 */

static VALUE
method_arity_m(VALUE method)
{
    int n = method_arity(method);
    return INT2FIX(n);
}

static int
method_arity(VALUE method)
{
    struct METHOD *data;

    Data_Get_Struct(method, struct METHOD, data);
    return rb_node_arity(data->body);
}

int
rb_mod_method_arity(VALUE mod, ID id)
{
    NODE *node = rb_method_node(mod, id);
    return rb_node_arity(node);
}

int
rb_obj_method_arity(VALUE obj, ID id)
{
    return rb_mod_method_arity(CLASS_OF(obj), id);
}

static rb_iseq_t *
get_method_iseq(VALUE method)
{
    struct METHOD *data;
    NODE *body;
    rb_iseq_t *iseq;

    Data_Get_Struct(method, struct METHOD, data);
    body = data->body;
    switch (nd_type(body)) {
      case NODE_BMETHOD:
	return get_proc_iseq(body->nd_cval, 0);
      case RUBY_VM_METHOD_NODE:
	GetISeqPtr((VALUE)body->nd_body, iseq);
	if (RUBY_VM_NORMAL_ISEQ_P(iseq)) break;
      default:
	return 0;
    }
    return iseq;
}

/*
 * call-seq:
 *    meth.source_location  => [String, Fixnum]
 *
 * returns the ruby source filename and line number containing this method
 * or nil if this method was not defined in ruby (i.e. native)
 */

VALUE
rb_method_location(VALUE method)
{
    return iseq_location(get_method_iseq(method));
}

/*
 * call-seq:
 *    meth.parameters  => array
 *
 * returns the parameter information of this method
 */

static VALUE
rb_method_parameters(VALUE method)
{
    rb_iseq_t *iseq = get_method_iseq(method);
    if (!iseq) {
	return unnamed_parameters(method_arity(method));
    }
    return rb_iseq_parameters(iseq, 0);
}

/*
 *  call-seq:
 *   meth.to_s      =>  string
 *   meth.inspect   =>  string
 *
 *  Show the name of the underlying method.
 *
 *    "cat".method(:count).inspect   #=> "#<Method: String#count>"
 */

static VALUE
method_inspect(VALUE method)
{
    struct METHOD *data;
    VALUE str;
    const char *s;
    const char *sharp = "#";

    Data_Get_Struct(method, struct METHOD, data);
    str = rb_str_buf_new2("#<");
    s = rb_obj_classname(method);
    rb_str_buf_cat2(str, s);
    rb_str_buf_cat2(str, ": ");

    if (FL_TEST(data->oclass, FL_SINGLETON)) {
	VALUE v = rb_iv_get(data->oclass, "__attached__");

	if (data->recv == Qundef) {
	    rb_str_buf_append(str, rb_inspect(data->oclass));
	}
	else if (data->recv == v) {
	    rb_str_buf_append(str, rb_inspect(v));
	    sharp = ".";
	}
	else {
	    rb_str_buf_append(str, rb_inspect(data->recv));
	    rb_str_buf_cat2(str, "(");
	    rb_str_buf_append(str, rb_inspect(v));
	    rb_str_buf_cat2(str, ")");
	    sharp = ".";
	}
    }
    else {
	rb_str_buf_cat2(str, rb_class2name(data->rclass));
	if (data->rclass != data->oclass) {
	    rb_str_buf_cat2(str, "(");
	    rb_str_buf_cat2(str, rb_class2name(data->oclass));
	    rb_str_buf_cat2(str, ")");
	}
    }
    rb_str_buf_cat2(str, sharp);
    rb_str_append(str, rb_id2str(data->oid));
    rb_str_buf_cat2(str, ">");

    return str;
}

static VALUE
mproc(VALUE method)
{
    return rb_funcall(Qnil, rb_intern("proc"), 0);
}

static VALUE
mlambda(VALUE method)
{
    return rb_funcall(Qnil, rb_intern("lambda"), 0);
}

static VALUE
bmcall(VALUE args, VALUE method)
{
    volatile VALUE a;

    if (CLASS_OF(args) != rb_cArray) {
	args = rb_ary_new3(1, args);
    }

    a = args;
    return rb_method_call(RARRAY_LEN(a), RARRAY_PTR(a), method);
}

VALUE
rb_proc_new(
    VALUE (*func)(ANYARGS), /* VALUE yieldarg[, VALUE procarg] */
    VALUE val)
{
    VALUE procval = rb_iterate(mproc, 0, func, val);
    return procval;
}

/*
 *  call-seq:
 *     meth.to_proc    => prc
 *
 *  Returns a <code>Proc</code> object corresponding to this method.
 */

static VALUE
method_proc(VALUE method)
{
    VALUE procval;
    rb_proc_t *proc;
    /*
     * class Method
     *   def to_proc
     *     proc{|*args|
     *       self.call(*args)
     *     }
     *   end
     * end
     */
    procval = rb_iterate(mlambda, 0, bmcall, method);
    GetProcPtr(procval, proc);
    proc->is_from_method = 1;
    return procval;
}

static VALUE
rb_obj_is_method(VALUE m)
{
    if (TYPE(m) == T_DATA && RDATA(m)->dmark == (RUBY_DATA_FUNC) bm_mark) {
	return Qtrue;
    }
    return Qfalse;
}

/*
 * call_seq:
 *   local_jump_error.exit_value  => obj
 *
 * Returns the exit value associated with this +LocalJumpError+.
 */
static VALUE
localjump_xvalue(VALUE exc)
{
    return rb_iv_get(exc, "@exit_value");
}

/*
 * call-seq:
 *    local_jump_error.reason   => symbol
 *
 * The reason this block was terminated:
 * :break, :redo, :retry, :next, :return, or :noreason.
 */

static VALUE
localjump_reason(VALUE exc)
{
    return rb_iv_get(exc, "@reason");
}

/*
 *  call-seq:
 *     prc.binding    => binding
 *
 *  Returns the binding associated with <i>prc</i>. Note that
 *  <code>Kernel#eval</code> accepts either a <code>Proc</code> or a
 *  <code>Binding</code> object as its second parameter.
 *
 *     def fred(param)
 *       proc {}
 *     end
 *
 *     b = fred(99)
 *     eval("param", b.binding)   #=> 99
 */
static VALUE
proc_binding(VALUE self)
{
    rb_proc_t *proc;
    VALUE bindval = binding_alloc(rb_cBinding);
    rb_binding_t *bind;

    GetProcPtr(self, proc);
    GetBindingPtr(bindval, bind);

    if (TYPE(proc->block.iseq) == T_NODE) {
	rb_raise(rb_eArgError, "Can't create Binding from C level Proc");
    }

    bind->env = proc->envval;
    return bindval;
}

static VALUE curry(VALUE dummy, VALUE args, int argc, VALUE *argv, VALUE passed_proc);

static VALUE
make_curry_proc(VALUE proc, VALUE passed, VALUE arity)
{
    VALUE args = rb_ary_new3(3, proc, passed, arity);
    rb_ary_freeze(passed);
    rb_ary_freeze(args);
    return rb_proc_new(curry, args);
}

static VALUE
curry(VALUE dummy, VALUE args, int argc, VALUE *argv, VALUE passed_proc)
{
    VALUE proc, passed, arity;
    proc = RARRAY_PTR(args)[0];
    passed = RARRAY_PTR(args)[1];
    arity = RARRAY_PTR(args)[2];

    passed = rb_ary_plus(passed, rb_ary_new4(argc, argv));
    rb_ary_freeze(passed);

    if(RARRAY_LEN(passed) < FIX2INT(arity)) {
	if (!NIL_P(passed_proc)) {
	    rb_warn("given block not used");
	}
	arity = make_curry_proc(proc, passed, arity);
	return arity;
    }
    else {
	return rb_proc_call_with_block(proc, RARRAY_LEN(passed), RARRAY_PTR(passed), passed_proc);
    }
}

 /*
  *  call-seq:
  *     prc.curry         => a_proc
  *     prc.curry(arity)  => a_proc
  *
  *  Returns a curried proc. If the optional <i>arity</i> argument is given,
  *  it determines the number of arguments.
  *  A curried proc receives some arguments. If a sufficient number of
  *  arguments are supplied, it passes the supplied arguments to the original
  *  proc and returns the result. Otherwise, returns another curried proc that
  *  takes the rest of arguments.
  *
  *     b = proc {|x, y, z| (x||0) + (y||0) + (z||0) }
  *     p b.curry[1][2][3]           #=> 6
  *     p b.curry[1, 2][3, 4]        #=> 6
  *     p b.curry(5)[1][2][3][4][5]  #=> 6
  *     p b.curry(5)[1, 2][3, 4][5]  #=> 6
  *     p b.curry(1)[1]              #=> 1
  *
  *     b = proc {|x, y, z, *w| (x||0) + (y||0) + (z||0) + w.inject(0, &:+) }
  *     p b.curry[1][2][3]           #=> 6
  *     p b.curry[1, 2][3, 4]        #=> 10
  *     p b.curry(5)[1][2][3][4][5]  #=> 15
  *     p b.curry(5)[1, 2][3, 4][5]  #=> 15
  *     p b.curry(1)[1]              #=> 1
  *
  *     b = lambda {|x, y, z| (x||0) + (y||0) + (z||0) }
  *     p b.curry[1][2][3]           #=> 6
  *     p b.curry[1, 2][3, 4]        #=> wrong number of arguments (4 or 3)
  *     p b.curry(5)                 #=> wrong number of arguments (5 or 3)
  *     p b.curry(1)                 #=> wrong number of arguments (1 or 3)
  *
  *     b = lambda {|x, y, z, *w| (x||0) + (y||0) + (z||0) + w.inject(0, &:+) }
  *     p b.curry[1][2][3]           #=> 6
  *     p b.curry[1, 2][3, 4]        #=> 10
  *     p b.curry(5)[1][2][3][4][5]  #=> 15
  *     p b.curry(5)[1, 2][3, 4][5]  #=> 15
  *     p b.curry(1)                 #=> wrong number of arguments (1 or 3)
  *
  *     b = proc { :foo }
  *     p b.curry[]                  #=> :foo
  */
static VALUE
proc_curry(int argc, VALUE *argv, VALUE self)
{
    int sarity, marity = FIX2INT(proc_arity(self));
    VALUE arity, opt = Qfalse;

    if (marity < 0) {
	marity = -marity - 1;
	opt = Qtrue;
    }

    rb_scan_args(argc, argv, "01", &arity);
    if (NIL_P(arity)) {
	arity = INT2FIX(marity);
    }
    else {
	sarity = FIX2INT(arity);
	if (proc_lambda_p(self) && (sarity < marity || (sarity > marity && !opt))) {
	    rb_raise(rb_eArgError, "wrong number of arguments (%d for %d)", sarity, marity);
	}
    }

    return make_curry_proc(self, rb_ary_new(), arity);
}

/*
 *  <code>Proc</code> objects are blocks of code that have been bound to
 *  a set of local variables. Once bound, the code may be called in
 *  different contexts and still access those variables.
 *
 *     def gen_times(factor)
 *       return Proc.new {|n| n*factor }
 *     end
 *
 *     times3 = gen_times(3)
 *     times5 = gen_times(5)
 *
 *     times3.call(12)               #=> 36
 *     times5.call(5)                #=> 25
 *     times3.call(times5.call(4))   #=> 60
 *
 */

void
Init_Proc(void)
{
    /* Proc */
    rb_cProc = rb_define_class("Proc", rb_cObject);
    rb_undef_alloc_func(rb_cProc);
    rb_define_singleton_method(rb_cProc, "new", rb_proc_s_new, -1);
    rb_define_method(rb_cProc, "call", proc_call, -1);
    rb_define_method(rb_cProc, "[]", proc_call, -1);
    rb_define_method(rb_cProc, "===", proc_call, -1);
    rb_define_method(rb_cProc, "yield", proc_call, -1);
    rb_define_method(rb_cProc, "to_proc", proc_to_proc, 0);
    rb_define_method(rb_cProc, "arity", proc_arity, 0);
    rb_define_method(rb_cProc, "clone", proc_clone, 0);
    rb_define_method(rb_cProc, "dup", proc_dup, 0);
    rb_define_method(rb_cProc, "==", proc_eq, 1);
    rb_define_method(rb_cProc, "eql?", proc_eq, 1);
    rb_define_method(rb_cProc, "hash", proc_hash, 0);
    rb_define_method(rb_cProc, "to_s", proc_to_s, 0);
    rb_define_method(rb_cProc, "lambda?", proc_lambda_p, 0);
    rb_define_method(rb_cProc, "binding", proc_binding, 0);
    rb_define_method(rb_cProc, "curry", proc_curry, -1);
    rb_define_method(rb_cProc, "source_location", rb_proc_location, 0);
    rb_define_method(rb_cProc, "parameters", rb_proc_parameters, 0);

    /* Exceptions */
    rb_eLocalJumpError = rb_define_class("LocalJumpError", rb_eStandardError);
    rb_define_method(rb_eLocalJumpError, "exit_value", localjump_xvalue, 0);
    rb_define_method(rb_eLocalJumpError, "reason", localjump_reason, 0);

    rb_eSysStackError = rb_define_class("SystemStackError", rb_eException);
    sysstack_error = rb_exc_new3(rb_eSysStackError,
				 rb_obj_freeze(rb_str_new2("stack level too deep")));
    OBJ_TAINT(sysstack_error);
    OBJ_FREEZE(sysstack_error);

    /* utility functions */
    rb_define_global_function("proc", rb_block_proc, 0);
    rb_define_global_function("lambda", proc_lambda, 0);

    /* Method */
    rb_cMethod = rb_define_class("Method", rb_cObject);
    rb_undef_alloc_func(rb_cMethod);
    rb_undef_method(CLASS_OF(rb_cMethod), "new");
    rb_define_method(rb_cMethod, "==", method_eq, 1);
    rb_define_method(rb_cMethod, "eql?", method_eq, 1);
    rb_define_method(rb_cMethod, "hash", method_hash, 0);
    rb_define_method(rb_cMethod, "clone", method_clone, 0);
    rb_define_method(rb_cMethod, "call", rb_method_call, -1);
    rb_define_method(rb_cMethod, "[]", rb_method_call, -1);
    rb_define_method(rb_cMethod, "arity", method_arity_m, 0);
    rb_define_method(rb_cMethod, "inspect", method_inspect, 0);
    rb_define_method(rb_cMethod, "to_s", method_inspect, 0);
    rb_define_method(rb_cMethod, "to_proc", method_proc, 0);
    rb_define_method(rb_cMethod, "receiver", method_receiver, 0);
    rb_define_method(rb_cMethod, "name", method_name, 0);
    rb_define_method(rb_cMethod, "owner", method_owner, 0);
    rb_define_method(rb_cMethod, "unbind", method_unbind, 0);
    rb_define_method(rb_cMethod, "source_location", rb_method_location, 0);
    rb_define_method(rb_cMethod, "parameters", rb_method_parameters, 0);
    rb_define_method(rb_mKernel, "method", rb_obj_method, 1);
    rb_define_method(rb_mKernel, "public_method", rb_obj_public_method, 1);

    /* UnboundMethod */
    rb_cUnboundMethod = rb_define_class("UnboundMethod", rb_cObject);
    rb_undef_alloc_func(rb_cUnboundMethod);
    rb_undef_method(CLASS_OF(rb_cUnboundMethod), "new");
    rb_define_method(rb_cUnboundMethod, "==", method_eq, 1);
    rb_define_method(rb_cUnboundMethod, "eql?", method_eq, 1);
    rb_define_method(rb_cUnboundMethod, "hash", method_hash, 0);
    rb_define_method(rb_cUnboundMethod, "clone", method_clone, 0);
    rb_define_method(rb_cUnboundMethod, "arity", method_arity_m, 0);
    rb_define_method(rb_cUnboundMethod, "inspect", method_inspect, 0);
    rb_define_method(rb_cUnboundMethod, "to_s", method_inspect, 0);
    rb_define_method(rb_cUnboundMethod, "name", method_name, 0);
    rb_define_method(rb_cUnboundMethod, "owner", method_owner, 0);
    rb_define_method(rb_cUnboundMethod, "bind", umethod_bind, 1);
    rb_define_method(rb_cUnboundMethod, "source_location", rb_method_location, 0);
    rb_define_method(rb_cUnboundMethod, "parameters", rb_method_parameters, 0);

    /* Module#*_method */
    rb_define_method(rb_cModule, "instance_method", rb_mod_instance_method, 1);
    rb_define_method(rb_cModule, "public_instance_method", rb_mod_public_instance_method, 1);
    rb_define_private_method(rb_cModule, "define_method", rb_mod_define_method, -1);

    /* Kernel */
    rb_define_method(rb_mKernel, "define_singleton_method", rb_obj_define_method, -1);
}

/*
 *  Objects of class <code>Binding</code> encapsulate the execution
 *  context at some particular place in the code and retain this context
 *  for future use. The variables, methods, value of <code>self</code>,
 *  and possibly an iterator block that can be accessed in this context
 *  are all retained. Binding objects can be created using
 *  <code>Kernel#binding</code>, and are made available to the callback
 *  of <code>Kernel#set_trace_func</code>.
 *
 *  These binding objects can be passed as the second argument of the
 *  <code>Kernel#eval</code> method, establishing an environment for the
 *  evaluation.
 *
 *     class Demo
 *       def initialize(n)
 *         @secret = n
 *       end
 *       def getBinding
 *         return binding()
 *       end
 *     end
 *
 *     k1 = Demo.new(99)
 *     b1 = k1.getBinding
 *     k2 = Demo.new(-3)
 *     b2 = k2.getBinding
 *
 *     eval("@secret", b1)   #=> 99
 *     eval("@secret", b2)   #=> -3
 *     eval("@secret")       #=> nil
 *
 *  Binding objects have no class-specific methods.
 *
 */

void
Init_Binding(void)
{
    rb_cBinding = rb_define_class("Binding", rb_cObject);
    rb_undef_alloc_func(rb_cBinding);
    rb_undef_method(CLASS_OF(rb_cBinding), "new");
    rb_define_method(rb_cBinding, "clone", binding_clone, 0);
    rb_define_method(rb_cBinding, "dup", binding_dup, 0);
    rb_define_method(rb_cBinding, "eval", bind_eval, -1);
    rb_define_global_function("binding", rb_f_binding, 0);
}