Fossil

Artifact [2aeace70]
Login

Artifact [2aeace70]

Artifact 2aeace70627de71587d04e4324a1989fe40ef4a6:


     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
  1993
  1994
  1995
  1996
  1997
  1998
  1999
  2000
  2001
  2002
  2003
  2004
  2005
  2006
  2007
  2008
  2009
  2010
  2011
  2012
  2013
  2014
  2015
  2016
  2017
  2018
  2019
  2020
  2021
  2022
  2023
  2024
  2025
  2026
  2027
  2028
  2029
  2030
  2031
  2032
  2033
  2034
  2035
  2036
  2037
  2038
  2039
  2040
  2041
  2042
  2043
  2044
  2045
  2046
  2047
  2048
  2049
  2050
  2051
  2052
  2053
  2054
  2055
  2056
  2057
  2058
  2059
  2060
  2061
  2062
  2063
  2064
  2065
  2066
  2067
  2068
  2069
  2070
  2071
  2072
  2073
  2074
  2075
  2076
  2077
  2078
  2079
  2080
  2081
  2082
  2083
  2084
  2085
  2086
  2087
  2088
  2089
  2090
  2091
  2092
  2093
  2094
  2095
  2096
  2097
  2098
  2099
  2100
  2101
  2102
  2103
  2104
  2105
  2106
  2107
  2108
  2109
  2110
  2111
  2112
  2113
  2114
  2115
  2116
  2117
  2118
  2119
  2120
  2121
  2122
  2123
  2124
  2125
  2126
  2127
  2128
  2129
  2130
  2131
  2132
  2133
  2134
  2135
  2136
  2137
  2138
  2139
  2140
  2141
  2142
  2143
  2144
  2145
  2146
  2147
  2148
  2149
  2150
  2151
  2152
  2153
  2154
  2155
  2156
  2157
  2158
  2159
  2160
  2161
  2162
  2163
  2164
  2165
  2166
  2167
  2168
  2169
  2170
  2171
  2172
  2173
  2174
  2175
  2176
  2177
  2178
  2179
  2180
  2181
  2182
  2183
  2184
  2185
  2186
  2187
  2188
  2189
  2190
  2191
  2192
  2193
  2194
  2195
  2196
  2197
  2198
  2199
  2200
  2201
  2202
  2203
  2204
  2205
  2206
  2207
  2208
  2209
  2210
  2211
  2212
  2213
  2214
  2215
  2216
  2217
  2218
  2219
  2220
  2221
  2222
  2223
  2224
  2225
  2226
  2227
  2228
  2229
  2230
  2231
  2232
  2233
  2234
  2235
  2236
  2237
  2238
  2239
  2240
  2241
  2242
  2243
  2244
  2245
  2246
  2247
  2248
  2249
  2250
  2251
  2252
  2253
  2254
  2255
  2256
  2257
  2258
  2259
  2260
  2261
  2262
  2263
  2264
  2265
  2266
  2267
  2268
  2269
  2270
  2271
  2272
  2273
  2274
  2275
  2276
  2277
  2278
  2279
  2280
  2281
  2282
  2283
  2284
  2285
  2286
  2287
  2288
  2289
  2290
  2291
  2292
  2293
  2294
  2295
  2296
  2297
  2298
  2299
  2300
  2301
  2302
  2303
  2304
  2305
  2306
  2307
  2308
  2309
  2310
  2311
  2312
  2313
  2314
  2315
  2316
  2317
  2318
  2319
  2320
  2321
  2322
  2323
  2324
  2325
  2326
  2327
  2328
  2329
  2330
  2331
  2332
  2333
  2334
  2335
  2336
  2337
  2338
  2339
  2340
  2341
  2342
  2343
  2344
  2345
  2346
  2347
  2348
  2349
  2350
  2351
  2352
  2353
  2354
  2355
  2356
  2357
  2358
  2359
  2360
  2361
  2362
  2363
  2364
  2365
  2366
  2367
  2368
  2369
  2370
  2371
  2372
  2373
  2374
  2375
  2376
  2377
  2378
  2379
  2380
  2381
  2382
  2383
  2384
  2385
  2386
  2387
  2388
  2389
  2390
  2391
  2392
  2393
  2394
  2395
  2396
  2397
  2398
  2399
  2400
  2401
  2402
  2403
  2404
  2405
  2406
  2407
  2408
  2409
  2410
  2411
  2412
  2413
  2414
  2415
  2416
  2417
  2418
  2419
  2420
  2421
  2422
  2423
  2424
  2425
  2426
  2427
  2428
  2429
  2430
  2431
  2432
  2433
  2434
  2435
  2436
  2437
  2438
  2439
  2440
  2441
  2442
  2443
  2444
  2445
  2446
  2447
  2448
  2449
  2450
  2451
  2452
  2453
  2454
  2455
  2456
  2457
  2458
  2459
  2460
  2461
  2462
  2463
  2464
  2465
  2466
  2467
  2468
  2469
  2470
  2471
  2472
  2473
  2474
  2475
  2476
  2477
  2478
  2479
  2480
  2481
  2482
  2483
  2484
  2485
  2486
  2487
  2488
  2489
  2490
  2491
  2492
  2493
  2494
  2495
  2496
  2497
  2498
  2499
  2500
  2501
  2502
  2503
  2504
  2505
  2506
  2507
  2508
  2509
  2510
  2511
  2512
  2513
  2514
  2515
  2516
  2517
  2518
  2519
  2520
  2521
  2522
  2523
  2524
  2525
  2526
  2527
  2528
  2529
  2530
  2531
  2532
  2533
  2534
  2535
  2536
  2537
  2538
  2539
  2540
  2541
  2542
  2543
  2544
  2545
  2546
  2547
  2548
  2549
  2550
  2551
  2552
  2553
  2554
  2555
  2556
  2557
  2558
  2559
  2560
  2561
  2562
  2563
  2564
  2565
  2566
  2567
  2568
  2569
  2570
  2571
  2572
  2573
  2574
  2575
  2576
  2577
  2578
  2579
  2580
  2581
  2582
  2583
  2584
  2585
  2586
  2587
  2588
  2589
  2590
  2591
  2592
  2593
  2594
  2595
  2596
  2597
  2598
  2599
  2600
  2601
  2602
  2603
  2604
  2605
  2606
  2607
  2608
  2609
  2610
  2611
  2612
  2613
  2614
  2615
  2616
  2617
  2618
  2619
  2620
  2621
  2622
  2623
  2624
  2625
  2626
  2627
  2628
  2629
  2630
  2631
  2632
  2633
  2634
  2635
  2636
  2637
  2638
  2639
  2640
  2641
  2642
  2643
  2644
  2645
  2646
  2647
  2648
  2649
  2650
  2651
  2652
  2653
  2654
  2655
  2656
  2657
  2658
  2659
  2660
  2661
  2662
  2663
  2664
  2665
  2666
  2667
  2668
  2669
  2670
  2671
  2672
  2673
  2674
  2675
  2676
  2677
  2678
  2679
  2680
  2681
  2682
  2683
  2684
  2685
  2686
  2687
  2688
  2689
  2690
  2691
  2692
  2693
  2694
  2695
  2696
  2697
  2698
  2699
  2700
  2701
  2702
  2703
  2704
  2705
  2706
  2707
  2708
  2709
  2710
  2711
  2712
  2713
  2714
  2715
  2716
  2717
  2718
  2719
  2720
  2721
  2722
  2723
  2724
  2725
  2726
  2727
  2728
  2729
  2730
  2731
  2732
  2733
  2734
  2735
  2736
  2737
  2738
  2739
  2740
  2741
  2742
  2743
  2744
  2745
  2746
  2747
  2748
  2749
  2750
  2751
  2752
  2753
  2754
  2755
  2756
  2757
  2758
  2759
  2760
  2761
  2762
  2763
  2764
  2765
  2766
  2767
  2768
  2769
  2770
  2771
  2772
  2773
  2774
  2775
  2776
  2777
  2778
  2779
  2780
  2781
  2782
  2783
  2784
  2785
  2786
  2787
  2788
  2789
  2790
  2791
  2792
  2793
  2794
  2795
  2796
  2797
  2798
  2799
  2800
  2801
  2802
  2803
  2804
  2805
  2806
  2807
  2808
  2809
  2810
  2811
  2812
  2813
  2814
  2815
  2816
  2817
  2818
  2819
  2820
  2821
  2822
  2823
  2824
  2825
  2826
  2827
  2828
  2829
  2830
  2831
  2832
  2833
  2834
  2835
  2836
  2837
  2838
  2839
  2840
  2841
  2842
  2843
  2844
  2845
  2846
  2847
  2848
  2849
  2850
  2851
  2852
  2853
  2854
  2855
  2856
  2857
  2858
  2859
  2860
  2861
  2862
  2863
  2864
  2865
  2866
  2867
  2868
  2869
  2870
  2871
  2872
  2873
  2874
  2875
  2876
  2877
  2878
  2879
  2880
  2881
  2882
  2883
  2884
  2885
  2886
  2887
  2888
  2889
  2890
  2891
  2892
  2893
  2894
  2895
  2896
  2897
  2898
  2899
  2900
  2901
  2902
  2903
  2904
  2905
  2906
  2907
  2908
  2909
  2910
  2911
  2912
  2913
  2914
  2915
  2916
  2917
  2918
  2919
  2920
  2921
  2922
  2923
  2924
  2925
  2926
  2927
  2928
  2929
  2930
  2931
  2932
  2933
  2934
  2935
  2936
  2937
  2938
  2939
  2940
  2941
  2942
  2943
  2944
  2945
  2946
  2947
  2948
  2949
  2950
  2951
  2952
  2953
  2954
  2955
  2956
  2957
  2958
  2959
  2960
  2961
  2962
  2963
  2964
  2965
  2966
  2967
  2968
  2969
  2970
  2971
  2972
  2973
  2974
  2975
  2976
  2977
  2978
  2979
  2980

/*
** The implementation of the TH core. This file contains the parser, and
** the implementation of the interface in th.h.
*/

#include "config.h"
#include "th.h"
#include <string.h>
#include <assert.h>

/*
** Values used for element values in the tcl_platform array.
*/

#if !defined(TH_ENGINE)
#  define TH_ENGINE          "TH1"
#endif

#if !defined(TH_PLATFORM)
#  if defined(_WIN32) || defined(WIN32)
#    define TH_PLATFORM      "windows"
#  else
#    define TH_PLATFORM      "unix"
#  endif
#endif

/*
** Forward declarations for structures defined below.
*/

typedef struct Th_Command        Th_Command;
typedef struct Th_Frame          Th_Frame;
typedef struct Th_Variable       Th_Variable;
typedef struct Th_InterpAndList  Th_InterpAndList;

/*
** Interpreter structure.
*/
struct Th_Interp {
  Th_Vtab *pVtab;     /* Copy of the argument passed to Th_CreateInterp() */
  char *zResult;      /* Current interpreter result (Th_Malloc()ed) */
  int nResult;        /* number of bytes in zResult */
  Th_Hash *paCmd;     /* Table of registered commands */
  Th_Frame *pFrame;   /* Current execution frame */
  int isListMode;     /* True if thSplitList() should operate in "list" mode */
};

/*
** Each TH command registered using Th_CreateCommand() is represented
** by an instance of the following structure stored in the Th_Interp.paCmd
** hash-table.
*/
struct Th_Command {
  int (*xProc)(Th_Interp *, void *, int, const char **, int *);
  void *pContext;
  void (*xDel)(Th_Interp *, void *);
};

/*
** Each stack frame (variable scope) is represented by an instance
** of this structure. Variable values set using the Th_SetVar command
** are stored in the Th_Frame.paVar hash table member of the associated
** stack frame object.
**
** When an interpreter is created, a single Th_Frame structure is also
** allocated - the global variable scope. Th_Interp.pFrame (the current
** interpreter frame) is initialised to point to this Th_Frame. It is
** not deleted for the lifetime of the interpreter (because the global
** frame never goes out of scope).
**
** New stack frames are created by the Th_InFrame() function. Before
** invoking its callback function, Th_InFrame() allocates a new Th_Frame
** structure with pCaller set to the current frame (Th_Interp.pFrame),
** and sets the current frame to the new frame object. After the callback
** has been invoked, the allocated Th_Frame is deleted and the value
** of the current frame pointer restored.
**
** By default, the Th_SetVar(), Th_UnsetVar() and Th_GetVar() functions
** access variable values in the current frame. If they need to access
** the global frame, they do so by traversing the pCaller pointer list.
** Likewise, the Th_LinkVar() function uses the pCaller pointers to
** link to variables located in the global or other stack frames.
*/
struct Th_Frame {
  Th_Hash *paVar;               /* Variables defined in this scope */
  Th_Frame *pCaller;            /* Calling frame */
};

/*
** This structure represents a value assigned to a th1 variable.
**
** The Th_Frame.paVar hash table maps from variable name (a th1 string)
** to a pointer to an instance of the following structure. More than
** one hash table entry may map to a single structure if variable
** links have been created using Th_LinkVar(). The number of references
** is stored in Th_Variable.nRef.
**
** For scalar variables, Th_Variable.zData is never 0. Th_Variable.nData
** stores the number of bytes in the value pointed to by zData.
**
** For an array variable, Th_Variable.zData is 0 and pHash points to
** a hash table mapping between array key name (a th1 string) and
** a pointer to the Th_Variable structure holding the scalar
** value.
*/
struct Th_Variable {
  int nRef;                   /* Number of references to this structure */
  int nData;                  /* Number of bytes at Th_Variable.zData */
  char *zData;                /* Data for scalar variables */
  Th_Hash *pHash;             /* Data for array variables */
};

/*
** This structure is used to pass complete context information to the
** hash iteration callback functions that need a Th_Interp and a list
** to operate on, e.g. thListAppendHashKey().
*/
struct Th_InterpAndList {
  Th_Interp *interp;          /* Associated interpreter context */
  char **pzList;              /* IN/OUT: Ptr to ptr to list */
  int *pnList;                /* IN/OUT: Current length of *pzList */
};

/*
** Hash table API:
*/
#define TH_HASHSIZE 257
struct Th_Hash {
  Th_HashEntry *a[TH_HASHSIZE];
};

static int thEvalLocal(Th_Interp *, const char *, int);
static int thSplitList(Th_Interp*, const char*, int, char***, int **, int*);

static int thHexdigit(char c);
static int thEndOfLine(const char *, int);

static int  thPushFrame(Th_Interp*, Th_Frame*);
static void thPopFrame(Th_Interp*);

static int thFreeVariable(Th_HashEntry*, void*);
static int thFreeCommand(Th_HashEntry*, void*);

/*
** The following are used by both the expression and language parsers.
** Given that the start of the input string (z, n) is a language
** construct of the relevant type (a command enclosed in [], an escape
** sequence etc.), these functions determine the number of bytes
** of the input consumed by the construct. For example:
**
**   int nByte;
**   thNextCommand(interp, "[expr $a+1] $nIter", 18, &nByte);
**
** results in variable nByte being set to 11. Or,
**
**   thNextVarname(interp, "$a+1", 4, &nByte);
**
** results in nByte being set to 2.
*/
static int thNextCommand(Th_Interp*, const char *z, int n, int *pN);
static int thNextEscape (Th_Interp*, const char *z, int n, int *pN);
static int thNextVarname(Th_Interp*, const char *z, int n, int *pN);
static int thNextNumber (Th_Interp*, const char *z, int n, int *pN);
static int thNextInteger (Th_Interp*, const char *z, int n, int *pN);
static int thNextSpace  (Th_Interp*, const char *z, int n, int *pN);

/*
** Given that the input string (z, n) contains a language construct of
** the relevant type (a command enclosed in [], an escape sequence
** like "\xFF" or a variable reference like "${varname}", perform
** substitution on the string and store the resulting string in
** the interpreter result.
*/
static int thSubstCommand(Th_Interp*, const char *z, int n);
static int thSubstEscape (Th_Interp*, const char *z, int n);
static int thSubstVarname(Th_Interp*, const char *z, int n);

/*
** Given that there is a th1 word located at the start of the input
** string (z, n), determine the length in bytes of that word. If the
** isCmd argument is non-zero, then an unescaped ";" byte not
** located inside of a block or quoted string is considered to mark
** the end of the word.
*/
static int thNextWord(Th_Interp*, const char *z, int n, int *pN, int isCmd);

/*
** Perform substitution on the word contained in the input string (z, n).
** Store the resulting string in the interpreter result.
*/
static int thSubstWord(Th_Interp*, const char *z, int n);

/*
** The Buffer structure and the thBufferXXX() functions are used to make
** memory allocation easier when building up a result.
*/
struct Buffer {
  char *zBuf;
  int nBuf;
  int nBufAlloc;
};
typedef struct Buffer Buffer;
static int  thBufferWrite(Th_Interp *interp, Buffer *, const char *, int);
static void thBufferInit(Buffer *);
static void thBufferFree(Th_Interp *interp, Buffer *);

/*
** Append nAdd bytes of content copied from zAdd to the end of buffer
** pBuffer. If there is not enough space currently allocated, resize
** the allocation to make space.
*/
static int thBufferWrite(
  Th_Interp *interp,
  Buffer *pBuffer,
  const char *zAdd,
  int nAdd
){
  int nReq;

  if( nAdd<0 ){
    nAdd = th_strlen(zAdd);
  }
  nReq = pBuffer->nBuf+nAdd+1;

  if( nReq>pBuffer->nBufAlloc ){
    char *zNew;
    int nNew;

    nNew = nReq*2;
    zNew = (char *)Th_Malloc(interp, nNew);
    memcpy(zNew, pBuffer->zBuf, pBuffer->nBuf);
    Th_Free(interp, pBuffer->zBuf);
    pBuffer->nBufAlloc = nNew;
    pBuffer->zBuf = zNew;
  }

  memcpy(&pBuffer->zBuf[pBuffer->nBuf], zAdd, nAdd);
  pBuffer->nBuf += nAdd;
  pBuffer->zBuf[pBuffer->nBuf] = '\0';

  return TH_OK;
}
#define thBufferWrite(a,b,c,d) thBufferWrite(a,b,(const char *)c,d)

/*
** Initialize the Buffer structure pointed to by pBuffer.
*/
static void thBufferInit(Buffer *pBuffer){
  memset(pBuffer, 0, sizeof(Buffer));
}

/*
** Zero the buffer pointed to by pBuffer and free the associated memory
** allocation.
*/
static void thBufferFree(Th_Interp *interp, Buffer *pBuffer){
  Th_Free(interp, pBuffer->zBuf);
  thBufferInit(pBuffer);
}

/*
** Assuming parameter c contains a hexadecimal digit character,
** return the corresponding value of that digit. If c is not
** a hexadecimal digit character, -1 is returned.
*/
static int thHexdigit(char c){
  switch (c) {
    case '0': return 0;
    case '1': return 1;
    case '2': return 2;
    case '3': return 3;
    case '4': return 4;
    case '5': return 5;
    case '6': return 6;
    case '7': return 7;
    case '8': return 8;
    case '9': return 9;
    case 'a': case 'A': return 10;
    case 'b': case 'B': return 11;
    case 'c': case 'C': return 12;
    case 'd': case 'D': return 13;
    case 'e': case 'E': return 14;
    case 'f': case 'F': return 15;
  }
  return -1;
}

/*
** Argument pEntry points to an entry in a stack frame hash table
** (Th_Frame.paVar). Decrement the reference count of the Th_Variable
** structure that the entry points to. Free the Th_Variable if its
** reference count reaches 0.
**
** Argument pContext is a pointer to the interpreter structure.
**
** Returns non-zero if the Th_Variable was actually freed.
*/
static int thFreeVariable(Th_HashEntry *pEntry, void *pContext){
  Th_Variable *pValue = (Th_Variable *)pEntry->pData;
  pValue->nRef--;
  assert( pValue->nRef>=0 );
  if( pValue->nRef==0 ){
    Th_Interp *interp = (Th_Interp *)pContext;
    Th_Free(interp, pValue->zData);
    if( pValue->pHash ){
      Th_HashIterate(interp, pValue->pHash, thFreeVariable, pContext);
      Th_HashDelete(interp, pValue->pHash);
    }
    Th_Free(interp, pValue);
    pEntry->pData = 0;
    return 1;
  }
  return 0;
}

/*
** Argument pEntry points to an entry in the command hash table
** (Th_Interp.paCmd). Delete the Th_Command structure that the
** entry points to.
**
** Argument pContext is a pointer to the interpreter structure.
**
** Always returns non-zero.
*/
static int thFreeCommand(Th_HashEntry *pEntry, void *pContext){
  Th_Command *pCommand = (Th_Command *)pEntry->pData;
  if( pCommand->xDel ){
    pCommand->xDel((Th_Interp *)pContext, pCommand->pContext);
  }
  Th_Free((Th_Interp *)pContext, pEntry->pData);
  pEntry->pData = 0;
  return 1;
}

/*
** Argument pEntry points to an entry in a hash table.  The key is
** the list element to be added.
**
** Argument pContext is a pointer to the Th_InterpAndList structure.
**
** Always returns non-zero.
*/
static int thListAppendHashKey(Th_HashEntry *pEntry, void *pContext){
  Th_InterpAndList *pInterpAndList = (Th_InterpAndList *)pContext;
  Th_ListAppend(pInterpAndList->interp, pInterpAndList->pzList,
                pInterpAndList->pnList, pEntry->zKey, pEntry->nKey);
  return 1;
}

/*
** Push a new frame onto the stack.
*/
static int thPushFrame(Th_Interp *interp, Th_Frame *pFrame){
  pFrame->paVar = Th_HashNew(interp);
  pFrame->pCaller = interp->pFrame;
  interp->pFrame = pFrame;
  return TH_OK;
}

/*
** Pop a frame off the top of the stack.
*/
static void thPopFrame(Th_Interp *interp){
  Th_Frame *pFrame = interp->pFrame;
  Th_HashIterate(interp, pFrame->paVar, thFreeVariable, (void *)interp);
  Th_HashDelete(interp, pFrame->paVar);
  interp->pFrame = pFrame->pCaller;
}

/*
** The first part of the string (zInput,nInput) contains an escape
** sequence. Set *pnEscape to the number of bytes in the escape sequence.
** If there is a parse error, return TH_ERROR and set the interpreter
** result to an error message. Otherwise return TH_OK.
*/
static int thNextEscape(
  Th_Interp *interp,
  const char *zInput,
  int nInput,
  int *pnEscape
){
  int i = 2;

  assert(nInput>0);
  assert(zInput[0]=='\\');

  if( nInput<=1 ){
    return TH_ERROR;
  }

  switch( zInput[1] ){
    case 'x': i = 4;
  }

  if( i>nInput ){
    return TH_ERROR;
  }
  *pnEscape = i;
  return TH_OK;
}

/*
** The first part of the string (zInput,nInput) contains a variable
** reference. Set *pnVarname to the number of bytes in the variable
** reference. If there is a parse error, return TH_ERROR and set the
** interpreter result to an error message. Otherwise return TH_OK.
*/
int thNextVarname(
  Th_Interp *interp,
  const char *zInput,
  int nInput,
  int *pnVarname
){
  int i;

  assert(nInput>0);
  assert(zInput[0]=='$');

  if( nInput>0 && zInput[1]=='{' ){
    for(i=2; i<nInput && zInput[i]!='}'; i++);
    if( i==nInput ){
      return TH_ERROR;
    }
    i++;
  }else{
    i = 1;
    if( nInput>2 && zInput[1]==':' && zInput[2]==':' ){
      i += 2;
    }
    for(; i<nInput; i++){
      if( zInput[i]=='(' ){
        for(i++; i<nInput; i++){
          if( zInput[i]==')' ) break;
          if( zInput[i]=='\\' ) i++;
          if( zInput[i]=='{' || zInput[i]=='[' || zInput[i]=='"' ){
            int nWord;
            int rc = thNextWord(interp, &zInput[i], nInput-i, &nWord, 0);
            if( rc!=TH_OK ){
              return rc;
            }
            i += nWord;
          }
        }
        if( i>=nInput ){
          Th_ErrorMessage(interp, "Unmatched brackets:", zInput, nInput);
          return TH_ERROR;
        }
        i++;
        break;
      }
      if( !th_isalnum(zInput[i]) && zInput[i]!='_' ) break;
    }
  }

  *pnVarname = i;
  return TH_OK;
}

/*
** The first part of the string (zInput,nInput) contains a command
** enclosed in a "[]" block. Set *pnCommand to the number of bytes in
** the variable reference. If there is a parse error, return TH_ERROR
** and set the interpreter result to an error message. Otherwise return
** TH_OK.
*/
int thNextCommand(
  Th_Interp *interp,
  const char *zInput,
  int nInput,
  int *pnCommand
){
  int nBrace = 0;
  int nSquare = 0;
  int i;

  assert(nInput>0);
  assert( zInput[0]=='[' || zInput[0]=='{' );

  for(i=0; i<nInput && (i==0 || nBrace>0 || nSquare>0); i++){
    switch( zInput[i] ){
      case '\\': i++; break;
      case '{': nBrace++; break;
      case '}': nBrace--; break;
      case '[': nSquare++; break;
      case ']': nSquare--; break;
    }
  }
  if( nBrace || nSquare ){
    return TH_ERROR;
  }

  *pnCommand = i;

  return TH_OK;
}

/*
** Set *pnSpace to the number of whitespace bytes at the start of
** input string (zInput, nInput). Always return TH_OK.
*/
int thNextSpace(
  Th_Interp *interp,
  const char *zInput,
  int nInput,
  int *pnSpace
){
  int i;
  for(i=0; i<nInput && th_isspace(zInput[i]); i++);
  *pnSpace = i;
  return TH_OK;
}

/*
** The first byte of the string (zInput,nInput) is not white-space.
** Set *pnWord to the number of bytes in the th1 word that starts
** with this byte. If a complete word cannot be parsed or some other
** error occurs, return TH_ERROR and set the interpreter result to
** an error message. Otherwise return TH_OK.
**
** If the isCmd argument is non-zero, then an unescaped ";" byte not
** located inside of a block or quoted string is considered to mark
** the end of the word.
*/
static int thNextWord(
  Th_Interp *interp,
  const char *zInput,
  int nInput,
  int *pnWord,
  int isCmd
){
  int iEnd = 0;

  assert( !th_isspace(zInput[0]) );

  if( zInput[0]=='"' ){
    /* The word is terminated by the next unescaped '"' character. */
    iEnd++;
    while( iEnd<nInput && zInput[iEnd]!='"' ){
      if( zInput[iEnd]=='\\' ){
        iEnd++;
      }
      iEnd++;
    }
    iEnd++;
  }else{
    int nBrace = 0;
    int nSq = 0;
    while( iEnd<nInput && (nBrace>0 || nSq>0 ||
      (!th_isspace(zInput[iEnd]) && (!isCmd || zInput[iEnd]!=';'))
    )){
      switch( zInput[iEnd] ){
        case '\\': iEnd++; break;
        case '{': if( nSq==0 ) nBrace++; break;
        case '}': if( nSq==0 ) nBrace--; break;
        case '[': if( nBrace==0 ) nSq++; break;
        case ']': if( nBrace==0 ) nSq--; break;
      }
      iEnd++;
    }
    if( nBrace>0 || nSq>0 ){
      /* Parse error */
      Th_SetResult(interp, "parse error", -1);
      return TH_ERROR;
    }
  }

  if( iEnd>nInput ){
    /* Parse error */
    Th_SetResult(interp, "parse error", -1);
    return TH_ERROR;
  }
  *pnWord = iEnd;
  return TH_OK;
}

/*
** The input string (zWord, nWord) contains a th1 script enclosed in
** a [] block. Perform substitution on the input string and store the
** resulting string in the interpreter result.
*/
static int thSubstCommand(
  Th_Interp *interp,
  const char *zWord,
  int nWord
){
  assert(nWord>=2);
  assert(zWord[0]=='[' && zWord[nWord-1]==']');
  return thEvalLocal(interp, &zWord[1], nWord-2);
}

/*
** The input string (zWord, nWord) contains a th1 variable reference
** (a '$' byte followed by a variable name). Perform substitution on
** the input string and store the resulting string in the interpreter
** result.
*/
static int thSubstVarname(
  Th_Interp *interp,
  const char *zWord,
  int nWord
){
  assert(nWord>=1);
  assert(zWord[0]=='$');
  assert(nWord==1 || zWord[1]!='{' || zWord[nWord-1]=='}');
  if( nWord>1 && zWord[1]=='{' ){
    zWord++;
    nWord -= 2;
  }else if( zWord[nWord-1]==')' ){
    int i;
    for(i=1; i<nWord && zWord[i]!='('; i++);
    if( i<nWord ){
      Buffer varname;
      int nInner;
      const char *zInner;

      int rc = thSubstWord(interp, &zWord[i+1], nWord-i-2);
      if( rc!=TH_OK ) return rc;

      zInner = Th_GetResult(interp, &nInner);
      thBufferInit(&varname);
      thBufferWrite(interp, &varname, &zWord[1], i);
      thBufferWrite(interp, &varname, zInner, nInner);
      thBufferWrite(interp, &varname, ")", 1);
      rc = Th_GetVar(interp, varname.zBuf, varname.nBuf);
      thBufferFree(interp, &varname);
      return rc;
    }
  }
  return Th_GetVar(interp, &zWord[1], nWord-1);
}

/*
** The input string (zWord, nWord) contains a th1 escape sequence.
** Perform substitution on the input string and store the resulting
** string in the interpreter result.
*/
static int thSubstEscape(
  Th_Interp *interp,
  const char *zWord,
  int nWord
){
  char c;

  assert(nWord>=2);
  assert(zWord[0]=='\\');

  switch( zWord[1] ){
    case 'x': {
      assert(nWord==4);
      c = ((thHexdigit(zWord[2])<<4) + thHexdigit(zWord[3]));
      break;
    }
    case 'n': {
      c = '\n';
      break;
    }
    default: {
      assert(nWord==2);
      c = zWord[1];
      break;
    }
  }

  Th_SetResult(interp, &c, 1);
  return TH_OK;
}

/*
** The input string (zWord, nWord) contains a th1 word. Perform
** substitution on the input string and store the resulting
** string in the interpreter result.
*/
static int thSubstWord(
  Th_Interp *interp,
  const char *zWord,
  int nWord
){
  int rc = TH_OK;
  Buffer output;
  int i;

  thBufferInit(&output);

  if( nWord>1 && (zWord[0]=='{' && zWord[nWord-1]=='}') ){
    rc = thBufferWrite(interp, &output, &zWord[1], nWord-2);
  }else{

    /* If the word is surrounded by double-quotes strip these away. */
    if( nWord>1 && (zWord[0]=='"' && zWord[nWord-1]=='"') ){
      zWord++;
      nWord -= 2;
    }

    for(i=0; rc==TH_OK && i<nWord; i++){
      int nGet;

      int (*xGet)(Th_Interp *, const char*, int, int *) = 0;
      int (*xSubst)(Th_Interp *, const char*, int) = 0;

      switch( zWord[i] ){
        case '\\':
          xGet = thNextEscape; xSubst = thSubstEscape;
          break;
        case '[':
          if( !interp->isListMode ){
            xGet = thNextCommand; xSubst = thSubstCommand;
            break;
          }
        case '$':
          if( !interp->isListMode ){
            xGet = thNextVarname; xSubst = thSubstVarname;
            break;
          }
        default: {
          thBufferWrite(interp, &output, &zWord[i], 1);
          continue; /* Go to the next iteration of the for(...) loop */
        }
      }

      rc = xGet(interp, &zWord[i], nWord-i, &nGet);
      if( rc==TH_OK ){
        rc = xSubst(interp, &zWord[i], nGet);
      }
      if( rc==TH_OK ){
        const char *zRes;
        int nRes;
        zRes = Th_GetResult(interp, &nRes);
        rc = thBufferWrite(interp, &output, zRes, nRes);
        i += (nGet-1);
      }
    }
  }

  if( rc==TH_OK ){
    Th_SetResult(interp, output.zBuf, output.nBuf);
  }
  thBufferFree(interp, &output);
  return rc;
}

/*
** Return true if one of the following is true of the buffer pointed
** to by zInput, length nInput:
**
**   + It is empty, or
**   + It contains nothing but white-space, or
**   + It contains no non-white-space characters before the first
**     newline character.
**
** Otherwise return false.
*/
static int thEndOfLine(const char *zInput, int nInput){
  int i;
  for(i=0; i<nInput && zInput[i]!='\n' && th_isspace(zInput[i]); i++);
  return ((i==nInput || zInput[i]=='\n')?1:0);
}

/*
** This function splits the supplied th1 list (contained in buffer zList,
** size nList) into elements and performs word-substitution on each
** element. If the Th_Interp.isListMode variable is true, then only
** escape sequences are substituted (used by the Th_SplitList() function).
** If Th_Interp.isListMode is false, then variable and command substitution
** is also performed (used by Th_Eval()).
**
** If zList/nList does not contain a valid list, TH_ERROR is returned
** and an error message stored in interp.
**
** If TH_OK is returned and pazElem is not NULL, the caller should free the
** pointer written to (*pazElem) using Th_Free(). This releases memory
** allocated for both the (*pazElem) and (*panElem) arrays. Example:
**
**     char **argv;
**     int *argl;
**     int argc;
**
**     // After this call, argv and argl point to valid arrays. The
**     // number of elements in each is argc.
**     //
**     Th_SplitList(interp, zList, nList, &argv, &argl, &argc);
**
**     // Free all memory allocated by Th_SplitList(). The arrays pointed
**     // to by argv and argl are invalidated by this call.
**     //
**     Th_Free(interp, argv);
**
*/
static int thSplitList(
  Th_Interp *interp,      /* Interpreter context */
  const char *zList,      /* Pointer to buffer containing input list */
  int nList,              /* Size of buffer pointed to by zList */
  char ***pazElem,        /* OUT: Array of list elements */
  int **panElem,          /* OUT: Lengths of each list element */
  int *pnCount            /* OUT: Number of list elements */
){
  int rc = TH_OK;

  Buffer strbuf;
  Buffer lenbuf;
  int nCount = 0;

  const char *zInput = zList;
  int nInput = nList;

  thBufferInit(&strbuf);
  thBufferInit(&lenbuf);

  while( nInput>0 ){
    const char *zWord;
    int nWord;

    thNextSpace(interp, zInput, nInput, &nWord);
    zInput += nWord;
    nInput = nList-(zInput-zList);

    if( TH_OK!=(rc = thNextWord(interp, zInput, nInput, &nWord, 0))
     || TH_OK!=(rc = thSubstWord(interp, zInput, nWord))
    ){
      goto finish;
    }
    zInput = &zInput[nWord];
    nInput = nList-(zInput-zList);
    if( nWord>0 ){
      zWord = Th_GetResult(interp, &nWord);
      thBufferWrite(interp, &strbuf, zWord, nWord);
      thBufferWrite(interp, &strbuf, "\0", 1);
      thBufferWrite(interp, &lenbuf, &nWord, sizeof(int));
      nCount++;
    }
  }
  assert((lenbuf.nBuf/sizeof(int))==nCount);

  assert((pazElem && panElem) || (!pazElem && !panElem));
  if( pazElem && rc==TH_OK ){
    int i;
    char *zElem;
    int *anElem;
    char **azElem = Th_Malloc(interp,
      sizeof(char*) * nCount +       /* azElem */
      sizeof(int) * nCount +         /* anElem */
      strbuf.nBuf                    /* space for list element strings */
    );
    anElem = (int *)&azElem[nCount];
    zElem = (char *)&anElem[nCount];
    memcpy(anElem, lenbuf.zBuf, lenbuf.nBuf);
    memcpy(zElem, strbuf.zBuf, strbuf.nBuf);
    for(i=0; i<nCount;i++){
      azElem[i] = zElem;
      zElem += (anElem[i] + 1);
    }
    *pazElem = azElem;
    *panElem = anElem;
  }
  if( pnCount ){
    *pnCount = nCount;
  }

 finish:
  thBufferFree(interp, &strbuf);
  thBufferFree(interp, &lenbuf);
  return rc;
}

/*
** Evaluate the th1 script contained in the string (zProgram, nProgram)
** in the current stack frame.
*/
static int thEvalLocal(Th_Interp *interp, const char *zProgram, int nProgram){
  int rc = TH_OK;
  const char *zInput = zProgram;
  int nInput = nProgram;

  while( rc==TH_OK && nInput ){
    Th_HashEntry *pEntry;
    int nSpace;
    const char *zFirst;

    char **argv;
    int *argl;
    int argc;

    assert(nInput>=0);

    /* Skip a semi-colon */
    if( *zInput==';' ){
      zInput++;
      nInput--;
    }

    /* Skip past leading white-space. */
    thNextSpace(interp, zInput, nInput, &nSpace);
    zInput += nSpace;
    nInput -= nSpace;
    zFirst = zInput;

    /* Check for a comment. If found, skip to the end of the line. */
    if( zInput[0]=='#' ){
      while( !thEndOfLine(zInput, nInput) ){
        zInput++;
        nInput--;
      }
      continue;
    }

    /* Gobble up input a word at a time until the end of the command
    ** (a semi-colon or end of line).
    */
    while( rc==TH_OK && *zInput!=';' && !thEndOfLine(zInput, nInput) ){
      int nWord=0;
      thNextSpace(interp, zInput, nInput, &nSpace);
      rc = thNextWord(interp, &zInput[nSpace], nInput-nSpace, &nWord, 1);
      zInput += (nSpace+nWord);
      nInput -= (nSpace+nWord);
    }
    if( rc!=TH_OK ) continue;

    /* Split the command into an array of words. This call also does
    ** substitution of each individual word.
    */
    rc = thSplitList(interp, zFirst, zInput-zFirst, &argv, &argl, &argc);
    if( rc!=TH_OK ) continue;

    if( argc>0 ){

      /* Look up the command name in the command hash-table. */
      pEntry = Th_HashFind(interp, interp->paCmd, argv[0], argl[0], 0);
      if( !pEntry ){
        Th_ErrorMessage(interp, "no such command: ", argv[0], argl[0]);
        rc = TH_ERROR;
      }

      /* Call the command procedure. */
      if( rc==TH_OK ){
        Th_Command *p = (Th_Command *)(pEntry->pData);
        const char **azArg = (const char **)argv;
        rc = p->xProc(interp, p->pContext, argc, azArg, argl);
      }

      /* If an error occurred, add this command to the stack trace report. */
      if( rc==TH_ERROR ){
        char *zRes;
        int nRes;
        char *zStack = 0;
        int nStack = 0;

        zRes = Th_TakeResult(interp, &nRes);
        if( TH_OK==Th_GetVar(interp, (char *)"::th_stack_trace", -1) ){
          zStack = Th_TakeResult(interp, &nStack);
        }
        Th_ListAppend(interp, &zStack, &nStack, zFirst, zInput-zFirst);
        Th_SetVar(interp, (char *)"::th_stack_trace", -1, zStack, nStack);
        Th_SetResult(interp, zRes, nRes);
        Th_Free(interp, zRes);
        Th_Free(interp, zStack);
      }
    }

    Th_Free(interp, argv);
  }

  return rc;
}

/*
** Interpret an integer frame identifier passed to either Th_Eval() or
** Th_LinkVar(). If successful, return a pointer to the identified
** Th_Frame structure. If unsuccessful (no such frame), return 0 and
** leave an error message in the interpreter result.
**
** Argument iFrame is interpreted as follows:
**
**   * If iFrame is 0, this means the current frame.
**
**   * If iFrame is negative, then the nth frame up the stack, where
**     n is the absolute value of iFrame. A value of -1 means the
**     calling procedure.
**
**   * If iFrame is +ve, then the nth frame from the bottom of the
**     stack. An iFrame value of 1 means the toplevel (global) frame.
*/
static Th_Frame *getFrame(Th_Interp *interp, int iFrame){
  Th_Frame *p = interp->pFrame;
  int i;
  if( iFrame>0 ){
    for(i=0; p; i++){
      p = p->pCaller;
    }
    iFrame = (i*-1) + iFrame;
    p = interp->pFrame;
  }
  for(i=0; p && i<(iFrame*-1); i++){
    p = p->pCaller;
  }

  if( !p ){
    char *zFrame;
    int nFrame;
    Th_SetResultInt(interp, iFrame);
    zFrame = Th_TakeResult(interp, &nFrame);
    Th_ErrorMessage(interp, "no such frame:", zFrame, nFrame);
    Th_Free(interp, zFrame);
  }
  return p;
}


/*
** Evaluate th1 script (zProgram, nProgram) in the frame identified by
** argument iFrame. Leave either an error message or a result in the
** interpreter result and return a th1 error code (TH_OK, TH_ERROR,
** TH_RETURN, TH_CONTINUE or TH_BREAK).
*/
int Th_Eval(Th_Interp *interp, int iFrame, const char *zProgram, int nProgram){
  int rc = TH_OK;
  Th_Frame *pSavedFrame = interp->pFrame;

  /* Set Th_Interp.pFrame to the frame that this script is to be
  ** evaluated in. The current frame is saved in pSavedFrame and will
  ** be restored before this function returns.
  */
  interp->pFrame = getFrame(interp, iFrame);

  if( !interp->pFrame ){
    rc = TH_ERROR;
  }else{
    int nInput = nProgram;

    if( nInput<0 ){
      nInput = th_strlen(zProgram);
    }
    rc = thEvalLocal(interp, zProgram, nInput);
  }

  interp->pFrame = pSavedFrame;
  return rc;
}

/*
** Input string (zVarname, nVarname) contains a th1 variable name. It
** may be a simple scalar variable name or it may be a reference
** to an array member. The variable name may or may not begin with
** "::", indicating that the name refers to a global variable, not
** a local scope one.
**
** This function inspects and categorizes the supplied variable name.
**
** If the name is a global reference, *pisGlobal is set to true. Otherwise
** false. Output string (*pzOuter, *pnOuter) is set to the variable name
** if it is a scalar reference, or the name of the array if it is an
** array variable. If the variable is a scalar, *pzInner is set to 0.
** If it is an array variable, (*pzInner, *pnInner) is set to the
** array key name.
*/
static int thAnalyseVarname(
  const char *zVarname,
  int nVarname,
  const char **pzOuter,      /* OUT: Pointer to scalar/array name */
  int *pnOuter,              /* OUT: Number of bytes at *pzOuter */
  const char **pzInner,      /* OUT: Pointer to array key (or null) */
  int *pnInner,              /* OUT: Number of bytes at *pzInner */
  int *pisGlobal             /* OUT: Set to true if this is a global ref */
){
  const char *zOuter = zVarname;
  int nOuter;
  const char *zInner = 0;
  int nInner = 0;
  int isGlobal = 0;
  int i;

  if( nVarname<0 ){
    nVarname = th_strlen(zVarname);
  }
  nOuter = nVarname;

  /* If the variable name starts with "::", then do the lookup is in the
  ** uppermost (global) frame.
  */
  if( nVarname>2 && zVarname[0]==':' && zVarname[1]==':' ){
    zOuter += 2;
    nOuter -= 2;
    isGlobal = 1;
  }

  /* Check if this is an array reference. */
  if( zOuter[nOuter-1]==')' ){
    for(i=0; i<nOuter; i++){
      if( zOuter[i]=='(' ){
        zInner = &zOuter[i+1];
        nInner = nOuter-i-2;
        nOuter = i;
        break;
      }
    }
  }

  *pzOuter = zOuter;
  *pnOuter = nOuter;
  *pzInner = zInner;
  *pnInner = nInner;
  *pisGlobal = isGlobal;
  return TH_OK;
}

/*
** The Find structure is used to return extra information to callers of the
** thFindValue function.  The fields within it are populated by thFindValue
** as soon as the necessary information is available.  Callers should check
** each field of interest upon return.
*/

struct Find {
  Th_HashEntry *pValueEntry; /* Pointer to the scalar or array hash entry */
  Th_HashEntry *pElemEntry;  /* Pointer to array element hash entry, if any */
  const char *zElem;         /* Name of array element, if applicable */
  int nElem;                 /* Length of array element name, if applicable */
};
typedef struct Find Find;

/*
** Input string (zVar, nVar) contains a variable name. This function locates
** the Th_Variable structure associated with the named variable. The
** variable name may be a global or local scalar or array variable
**
** If the create argument is non-zero and the named variable does not exist
** it is created. Otherwise, an error is left in the interpreter result
** and NULL returned.
**
** If the arrayok argument is false and the named variable is an array,
** an error is left in the interpreter result and NULL returned. If
** arrayok is true an array name is Ok.
*/

static Th_Variable *thFindValue(
  Th_Interp *interp,
  const char *zVar,       /* Pointer to variable name */
  int nVar,               /* Number of bytes at nVar */
  int create,             /* If true, create the variable if not found */
  int arrayok,            /* If true, an array is Ok. Otherwise array==error */
  int noerror,            /* If false, set interpreter result to error */
  Find *pFind             /* If non-zero, place output here */
){
  const char *zOuter;
  int nOuter;
  const char *zInner;
  int nInner;
  int isGlobal;

  Th_HashEntry *pEntry;
  Th_Frame *pFrame = interp->pFrame;
  Th_Variable *pValue;

  thAnalyseVarname(zVar, nVar, &zOuter, &nOuter, &zInner, &nInner, &isGlobal);
  if( pFind ){
    memset(pFind, 0, sizeof(Find));
    pFind->zElem = zInner;
    pFind->nElem = nInner;
  }
  if( isGlobal ){
    while( pFrame->pCaller ) pFrame = pFrame->pCaller;
  }

  pEntry = Th_HashFind(interp, pFrame->paVar, zOuter, nOuter, create);
  assert(pEntry || create<=0);
  if( pFind ){
    pFind->pValueEntry = pEntry;
  }
  if( !pEntry ){
    goto no_such_var;
  }

  pValue = (Th_Variable *)pEntry->pData;
  if( !pValue ){
    assert(create);
    pValue = Th_Malloc(interp, sizeof(Th_Variable));
    pValue->nRef = 1;
    pEntry->pData = (void *)pValue;
  }

  if( zInner ){
    if( pValue->zData ){
      if( !noerror ){
        Th_ErrorMessage(interp, "variable is a scalar:", zOuter, nOuter);
      }
      return 0;
    }
    if( !pValue->pHash ){
      if( !create ){
        goto no_such_var;
      }
      pValue->pHash = Th_HashNew(interp);
    }
    pEntry = Th_HashFind(interp, pValue->pHash, zInner, nInner, create);
    assert(pEntry || create<=0);
    if( pFind ){
      pFind->pElemEntry = pEntry;
    }
    if( !pEntry ){
      goto no_such_var;
    }
    pValue = (Th_Variable *)pEntry->pData;
    if( !pValue ){
      assert(create);
      pValue = Th_Malloc(interp, sizeof(Th_Variable));
      pValue->nRef = 1;
      pEntry->pData = (void *)pValue;
    }
  }else{
    if( pValue->pHash && !arrayok ){
      if( !noerror ){
        Th_ErrorMessage(interp, "variable is an array:", zOuter, nOuter);
      }
      return 0;
    }
  }

  return pValue;

no_such_var:
  if( !noerror ){
    Th_ErrorMessage(interp, "no such variable:", zVar, nVar);
  }
  return 0;
}

/*
** String (zVar, nVar) must contain the name of a scalar variable or
** array member. Look up the variable, store its current value in
** the interpreter result and return TH_OK.
**
** If the named variable does not exist, return TH_ERROR and leave
** an error message in the interpreter result.
*/
int Th_GetVar(Th_Interp *interp, const char *zVar, int nVar){
  Th_Variable *pValue;

  pValue = thFindValue(interp, zVar, nVar, 0, 0, 0, 0);
  if( !pValue ){
    return TH_ERROR;
  }
  if( !pValue->zData ){
    Th_ErrorMessage(interp, "no such variable:", zVar, nVar);
    return TH_ERROR;
  }

  return Th_SetResult(interp, pValue->zData, pValue->nData);
}

/*
** Return true if variable (zVar, nVar) exists.
*/
int Th_ExistsVar(Th_Interp *interp, const char *zVar, int nVar){
  Th_Variable *pValue = thFindValue(interp, zVar, nVar, 0, 1, 1, 0);
  return pValue && (pValue->zData || pValue->pHash);
}

/*
** Return true if array variable (zVar, nVar) exists.
*/
int Th_ExistsArrayVar(Th_Interp *interp, const char *zVar, int nVar){
  Th_Variable *pValue = thFindValue(interp, zVar, nVar, 0, 1, 1, 0);
  return pValue && !pValue->zData && pValue->pHash;
}

/*
** String (zVar, nVar) must contain the name of a scalar variable or
** array member. If the variable does not exist it is created. The
** variable is set to the value supplied in string (zValue, nValue).
**
** If (zVar, nVar) refers to an existing array, TH_ERROR is returned
** and an error message left in the interpreter result.
*/
int Th_SetVar(
  Th_Interp *interp,
  const char *zVar,
  int nVar,
  const char *zValue,
  int nValue
){
  Th_Variable *pValue;

  pValue = thFindValue(interp, zVar, nVar, 1, 0, 0, 0);
  if( !pValue ){
    return TH_ERROR;
  }

  if( nValue<0 ){
    nValue = th_strlen(zValue);
  }
  if( pValue->zData ){
    Th_Free(interp, pValue->zData);
    pValue->zData = 0;
  }

  assert(zValue || nValue==0);
  pValue->zData = Th_Malloc(interp, nValue+1);
  pValue->zData[nValue] = '\0';
  memcpy(pValue->zData, zValue, nValue);
  pValue->nData = nValue;

  return TH_OK;
}

/*
** Create a variable link so that accessing variable (zLocal, nLocal) is
** the same as accessing variable (zLink, nLink) in stack frame iFrame.
*/
int Th_LinkVar(
  Th_Interp *interp,                 /* Interpreter */
  const char *zLocal, int nLocal,    /* Local varname */
  int iFrame,                        /* Stack frame of linked var */
  const char *zLink, int nLink       /* Linked varname */
){
  Th_Frame *pSavedFrame = interp->pFrame;
  Th_Frame *pFrame;
  Th_HashEntry *pEntry;
  Th_Variable *pValue;

  pFrame = getFrame(interp, iFrame);
  if( !pFrame ){
    return TH_ERROR;
  }
  pSavedFrame = interp->pFrame;
  interp->pFrame = pFrame;
  pValue = thFindValue(interp, zLink, nLink, 1, 1, 0, 0);
  interp->pFrame = pSavedFrame;

  pEntry = Th_HashFind(interp, interp->pFrame->paVar, zLocal, nLocal, 1);
  if( pEntry->pData ){
    Th_ErrorMessage(interp, "variable exists:", zLocal, nLocal);
    return TH_ERROR;
  }
  pEntry->pData = (void *)pValue;
  pValue->nRef++;

  return TH_OK;
}

/*
** Input string (zVar, nVar) must contain the name of a scalar variable,
** an array, or an array member. If the identified variable exists, it
** is deleted and TH_OK returned. Otherwise, an error message is left
** in the interpreter result and TH_ERROR is returned.
*/
int Th_UnsetVar(Th_Interp *interp, const char *zVar, int nVar){
  Find find;
  Th_Variable *pValue;
  Th_HashEntry *pEntry;
  int rc = TH_ERROR;

  pValue = thFindValue(interp, zVar, nVar, 0, 1, 0, &find);
  if( !pValue ){
    return rc;
  }

  if( pValue->zData || pValue->pHash ){
    rc = TH_OK;
  }else {
    Th_ErrorMessage(interp, "no such variable:", zVar, nVar);
  }

  /*
  ** The variable may be shared by more than one frame; therefore, make sure
  ** it is actually freed prior to freeing the parent structure.  The values
  ** for the variable must be freed now so the variable appears undefined in
  ** all frames.  The hash entry in the current frame must also be deleted
  ** now; otherwise, if the current stack frame is later popped, it will try
  ** to delete a variable which has already been freed.
  */
  if( find.zElem ){
    pEntry = find.pElemEntry;
  }else{
    pEntry = find.pValueEntry;
  }
  assert( pEntry );
  assert( pValue );
  if( thFreeVariable(pEntry, (void *)interp) ){
    if( find.zElem ){
      Th_Variable *pValue2 = find.pValueEntry->pData;
      Th_HashFind(interp, pValue2->pHash, find.zElem, find.nElem, -1);
    }else if( pEntry->pData ){
      Th_Free(interp, pEntry->pData);
      pEntry->pData = 0;
    }
  }else{
    if( pValue->zData ){
      Th_Free(interp, pValue->zData);
      pValue->zData = 0;
    }
    if( pValue->pHash ){
      Th_HashIterate(interp, pValue->pHash, thFreeVariable, (void *)interp);
      Th_HashDelete(interp, pValue->pHash);
      pValue->pHash = 0;
    }
    if( find.zElem ){
      Th_Variable *pValue2 = find.pValueEntry->pData;
      Th_HashFind(interp, pValue2->pHash, find.zElem, find.nElem, -1);
    }
  }
  if( !find.zElem ){
    Th_HashFind(interp, interp->pFrame->paVar, zVar, nVar, -1);
  }
  return rc;
}

/*
** Return an allocated buffer containing a copy of string (z, n). The
** caller is responsible for eventually calling Th_Free() to free
** the returned buffer.
*/
char *th_strdup(Th_Interp *interp, const char *z, int n){
  char *zRes;
  if( n<0 ){
    n = th_strlen(z);
  }
  zRes = Th_Malloc(interp, n+1);
  memcpy(zRes, z, n);
  zRes[n] = '\0';
  return zRes;
}

/*
** Argument zPre must be a nul-terminated string. Set the interpreter
** result to a string containing the contents of zPre, followed by
** a space (" ") character, followed by a copy of string (z, n).
**
** In other words, the equivalent of:
*
**     printf("%s %.*s", zPre, n, z);
**
** Example:
**
**     Th_ErrorMessage(interp, "no such variable:", zVarname, nVarname);
**
*/
int Th_ErrorMessage(Th_Interp *interp, const char *zPre, const char *z, int n){
  if( interp ){
    char *zRes = 0;
    int nRes = 0;

    Th_SetVar(interp, (char *)"::th_stack_trace", -1, 0, 0);

    Th_StringAppend(interp, &zRes, &nRes, zPre, -1);
    if( zRes[nRes-1]=='"' ){
      Th_StringAppend(interp, &zRes, &nRes, z, n);
      Th_StringAppend(interp, &zRes, &nRes, (const char *)"\"", 1);
    }else{
      Th_StringAppend(interp, &zRes, &nRes, (const char *)" ", 1);
      Th_StringAppend(interp, &zRes, &nRes, z, n);
    }

    Th_SetResult(interp, zRes, nRes);
    Th_Free(interp, zRes);
  }

  return TH_OK;
}

/*
** Set the current interpreter result by taking a copy of the buffer
** pointed to by z, size n bytes. TH_OK is always returned.
*/
int Th_SetResult(Th_Interp *pInterp, const char *z, int n){

  /* Free the current result */
  Th_Free(pInterp, pInterp->zResult);
  pInterp->zResult = 0;
  pInterp->nResult = 0;

  if( n<0 ){
    n = th_strlen(z);
  }

  if( z && n>0 ){
    char *zResult;
    zResult = Th_Malloc(pInterp, n+1);
    memcpy(zResult, z, n);
    zResult[n] = '\0';
    pInterp->zResult = zResult;
    pInterp->nResult = n;
  }

  return TH_OK;
}

/*
** Return a pointer to the buffer containing the current interpreter
** result. If pN is not NULL, set *pN to the size of the returned
** buffer.
*/
const char *Th_GetResult(Th_Interp *pInterp, int *pN){
  assert(pInterp->zResult || pInterp->nResult==0);
  if( pN ){
    *pN = pInterp->nResult;
  }
  return (pInterp->zResult ? pInterp->zResult : (const char *)"");
}

/*
** Return a pointer to the buffer containing the current interpreter
** result. If pN is not NULL, set *pN to the size of the returned
** buffer.
**
** This function is the same as Th_GetResult() except that the
** caller is responsible for eventually calling Th_Free() on the
** returned buffer. The internal interpreter result is cleared
** after this function is called.
*/
char *Th_TakeResult(Th_Interp *pInterp, int *pN){
  if( pN ){
    *pN = pInterp->nResult;
  }
  if( pInterp->zResult ){
    char *zResult = pInterp->zResult;
    pInterp->zResult = 0;
    pInterp->nResult = 0;
    return zResult;
  }else{
    return (char *)Th_Malloc(pInterp, 1);
  }
}


/*
** Wrappers around the supplied malloc() and free()
*/
void *Th_Malloc(Th_Interp *pInterp, int nByte){
  void *p = pInterp->pVtab->xMalloc(nByte);
  if( p ){
    memset(p, 0, nByte);
  }
  return p;
}
void Th_Free(Th_Interp *pInterp, void *z){
  if( z ){
    pInterp->pVtab->xFree(z);
  }
}

/*
** Install a new th1 command.
**
** If a command of the same name already exists, it is deleted automatically.
*/
int Th_CreateCommand(
  Th_Interp *interp,
  const char *zName,                 /* New command name */
  Th_CommandProc xProc,              /* Command callback proc */
  void *pContext,                    /* Value to pass as second arg to xProc */
  void (*xDel)(Th_Interp *, void *)  /* Command destructor callback */
){
  Th_HashEntry *pEntry;
  Th_Command *pCommand;

  pEntry = Th_HashFind(interp, interp->paCmd, (const char *)zName, -1, 1);
  if( pEntry->pData ){
    pCommand = pEntry->pData;
    if( pCommand->xDel ){
      pCommand->xDel(interp, pCommand->pContext);
    }
  }else{
    pCommand = Th_Malloc(interp, sizeof(Th_Command));
  }
  pCommand->xProc = xProc;
  pCommand->pContext = pContext;
  pCommand->xDel = xDel;
  pEntry->pData = (void *)pCommand;

  return TH_OK;
}

/*
** Rename the existing command (zName, nName) to (zNew, nNew). If nNew is 0,
** the command is deleted instead of renamed.
**
** If successful, TH_OK is returned. If command zName does not exist, or
** if command zNew already exists, an error message is left in the
** interpreter result and TH_ERROR is returned.
*/
int Th_RenameCommand(
  Th_Interp *interp,
  const char *zName,             /* Existing command name */
  int nName,                     /* Number of bytes at zName */
  const char *zNew,              /* New command name */
  int nNew                       /* Number of bytes at zNew */
){
  Th_HashEntry *pEntry;
  Th_HashEntry *pNewEntry;

  pEntry = Th_HashFind(interp, interp->paCmd, zName, nName, 0);
  if( !pEntry ){
    Th_ErrorMessage(interp, "no such command:", zName, nName);
    return TH_ERROR;
  }
  assert(pEntry->pData);

  if( nNew>0 ){
    pNewEntry = Th_HashFind(interp, interp->paCmd, zNew, nNew, 1);
    if( pNewEntry->pData ){
      Th_ErrorMessage(interp, "command exists:", zNew, nNew);
      return TH_ERROR;
    }
    pNewEntry->pData = pEntry->pData;
  }else{
    Th_Command *pCommand = (Th_Command *)(pEntry->pData);
    if( pCommand->xDel ){
      pCommand->xDel(interp, pCommand->pContext);
    }
    Th_Free(interp, pCommand);
  }

  Th_HashFind(interp, interp->paCmd, zName, nName, -1);
  return TH_OK;
}

/*
** Push a stack frame onto the interpreter stack, invoke the
** callback, and pop the frame back off again. See the implementation
** of [proc] (th_lang.c) for an example.
*/
int Th_InFrame(Th_Interp *interp,
  int (*xCall)(Th_Interp *, void *pContext1, void *pContext2),
  void *pContext1,
  void *pContext2
){
  Th_Frame frame;
  int rc;
  thPushFrame(interp, &frame);
  rc = xCall(interp, pContext1, pContext2);
  thPopFrame(interp);
  return rc;
}

/*
** Split a th1 list into its component elements. The list to split is
** passed via arguments (zList, nList). If successful, TH_OK is returned.
** If an error occurs (if (zList, nList) is not a valid list) an error
** message is left in the interpreter result and TH_ERROR returned.
**
** If successful, *pnCount is set to the number of elements in the list.
** panElem is set to point at an array of *pnCount integers - the lengths
** of the element values. *pazElem is set to point at an array of
** pointers to buffers containing the array element's data.
**
** To free the arrays allocated at *pazElem and *panElem, the caller
** should call Th_Free() on *pazElem only. Exactly one such call to
** Th_Free() must be made per call to Th_SplitList().
**
** Example:
**
**     int nElem;
**     int *anElem;
**     char **azElem;
**     int i;
**
**     Th_SplitList(interp, zList, nList, &azElem, &anElem, &nElem);
**     for(i=0; i<nElem; i++){
**       int nData = anElem[i];
**       char *zData = azElem[i];
**       ...
**     }
**
**     Th_Free(interp, azElem);
**
*/
int Th_SplitList(
  Th_Interp *interp,
  const char *zList,              /* Pointer to buffer containing list */
  int nList,                      /* Number of bytes at zList */
  char ***pazElem,                /* OUT: Array of pointers to element data */
  int **panElem,                  /* OUT: Array of element data lengths */
  int *pnCount                    /* OUT: Number of elements in list */
){
  int rc;
  interp->isListMode = 1;
  rc = thSplitList(interp, zList, nList, pazElem, panElem, pnCount);
  interp->isListMode = 0;
  if( rc ){
    Th_ErrorMessage(interp, "Expected list, got: \"", zList, nList);
  }
  return rc;
}

/*
** Append a new element to an existing th1 list. The element to append
** to the list is (zElem, nElem).
**
** A pointer to the existing list must be stored at *pzList when this
** function is called. The length must be stored in *pnList. The value
** of *pzList must either be NULL (in which case *pnList must be 0), or
** a pointer to memory obtained from Th_Malloc().
**
** This function calls Th_Free() to free the buffer at *pzList and sets
** *pzList to point to a new buffer containing the new list value. *pnList
** is similarly updated before returning. The return value is always TH_OK.
**
** Example:
**
**     char *zList = 0;
**     int nList = 0;
**     for (...) {
**       char *zElem = <some expression>;
**       Th_ListAppend(interp, &zList, &nList, zElem, -1);
**     }
**     Th_SetResult(interp, zList, nList);
**     Th_Free(interp, zList);
**
*/
int Th_ListAppend(
  Th_Interp *interp,           /* Interpreter context */
  char **pzList,               /* IN/OUT: Ptr to ptr to list */
  int *pnList,                 /* IN/OUT: Current length of *pzList */
  const char *zElem,           /* Data to append */
  int nElem                    /* Length of nElem */
){
  Buffer output;
  int i;

  int hasSpecialChar = 0;
  int hasEscapeChar = 0;
  int nBrace = 0;

  output.zBuf = *pzList;
  output.nBuf = *pnList;
  output.nBufAlloc = output.nBuf;

  if( nElem<0 ){
    nElem = th_strlen(zElem);
  }
  if( output.nBuf>0 ){
    thBufferWrite(interp, &output, " ", 1);
  }

  for(i=0; i<nElem; i++){
    char c = zElem[i];
    if( th_isspecial(c) ) hasSpecialChar = 1;
    if( c=='\\' ) hasEscapeChar = 1;
    if( c=='{' ) nBrace++;
    if( c=='}' ) nBrace--;
  }

  if( nElem==0 || (!hasEscapeChar && hasSpecialChar && nBrace==0) ){
    thBufferWrite(interp, &output, "{", 1);
    thBufferWrite(interp, &output, zElem, nElem);
    thBufferWrite(interp, &output, "}", 1);
  }else{
    for(i=0; i<nElem; i++){
      char c = zElem[i];
      if( th_isspecial(c) ) thBufferWrite(interp, &output, "\\", 1);
      thBufferWrite(interp, &output, &c, 1);
    }
  }

  *pzList = output.zBuf;
  *pnList = output.nBuf;

  return TH_OK;
}

/*
** Append a new element to an existing th1 string. This function uses
** the same interface as the Th_ListAppend() function.
*/
int Th_StringAppend(
  Th_Interp *interp,           /* Interpreter context */
  char **pzStr,                /* IN/OUT: Ptr to ptr to list */
  int *pnStr,                  /* IN/OUT: Current length of *pzStr */
  const char *zElem,           /* Data to append */
  int nElem                    /* Length of nElem */
){
  char *zNew;
  int nNew;

  if( nElem<0 ){
    nElem = th_strlen(zElem);
  }

  nNew = *pnStr + nElem;
  zNew = Th_Malloc(interp, nNew);
  memcpy(zNew, *pzStr, *pnStr);
  memcpy(&zNew[*pnStr], zElem, nElem);

  Th_Free(interp, *pzStr);
  *pzStr = zNew;
  *pnStr = nNew;

  return TH_OK;
}

/*
** Initialize an interpreter.
*/
static int thInitialize(Th_Interp *interp){
  assert(interp->pFrame);

  Th_SetVar(interp, (char *)"::tcl_platform(engine)", -1, TH_ENGINE, -1);
  Th_SetVar(interp, (char *)"::tcl_platform(platform)", -1, TH_PLATFORM, -1);

  return TH_OK;
}

/*
** Delete an interpreter.
*/
void Th_DeleteInterp(Th_Interp *interp){
  assert(interp->pFrame);
  assert(0==interp->pFrame->pCaller);

  /* Delete the contents of the global frame. */
  thPopFrame(interp);

  /* Delete any result currently stored in the interpreter. */
  Th_SetResult(interp, 0, 0);

  /* Delete all registered commands and the command hash-table itself. */
  Th_HashIterate(interp, interp->paCmd, thFreeCommand, (void *)interp);
  Th_HashDelete(interp, interp->paCmd);

  /* Delete the interpreter structure itself. */
  Th_Free(interp, (void *)interp);
}

/*
** Create a new interpreter.
*/
Th_Interp * Th_CreateInterp(Th_Vtab *pVtab){
  Th_Interp *p;

  /* Allocate and initialise the interpreter and the global frame */
  p = pVtab->xMalloc(sizeof(Th_Interp) + sizeof(Th_Frame));
  memset(p, 0, sizeof(Th_Interp));
  p->pVtab = pVtab;
  p->paCmd = Th_HashNew(p);
  thPushFrame(p, (Th_Frame *)&p[1]);
  thInitialize(p);

  return p;
}

/*
** These two types are used only by the expression module, where
** the expression module means the Th_Expr() and exprXXX() functions.
*/
typedef struct Operator Operator;
struct Operator {
  const char *zOp;
  int nOp;
  int eOp;
  int iPrecedence;
  int eArgType;
};
typedef struct Expr Expr;
struct Expr {
  Operator *pOp;
  Expr *pParent;
  Expr *pLeft;
  Expr *pRight;

  char *zValue;      /* Pointer to literal value */
  int nValue;        /* Length of literal value buffer */
};

/* Unary operators */
#define OP_UNARY_MINUS  2
#define OP_UNARY_PLUS   3
#define OP_BITWISE_NOT  4
#define OP_LOGICAL_NOT  5

/* Binary operators */
#define OP_MULTIPLY     6
#define OP_DIVIDE       7
#define OP_MODULUS      8
#define OP_ADD          9
#define OP_SUBTRACT    10
#define OP_LEFTSHIFT   11
#define OP_RIGHTSHIFT  12
#define OP_LT          13
#define OP_GT          14
#define OP_LE          15
#define OP_GE          16
#define OP_EQ          17
#define OP_NE          18
#define OP_SEQ         19
#define OP_SNE         20
#define OP_BITWISE_AND 21
#define OP_BITWISE_XOR 22
#define OP_BITWISE_OR  24
#define OP_LOGICAL_AND 25
#define OP_LOGICAL_OR  26

/* Other symbols */
#define OP_OPEN_BRACKET  27
#define OP_CLOSE_BRACKET 28

/* Argument types. Each operator in the expression syntax is defined
** as requiring either integer, number (real or integer) or string
** operands.
*/
#define ARG_INTEGER 1
#define ARG_NUMBER  2
#define ARG_STRING  3

static Operator aOperator[] = {

  {"(",  1, OP_OPEN_BRACKET,   -1, 0},
  {")",  1, OP_CLOSE_BRACKET, -1, 0},

  /* Note: all unary operators have (iPrecedence==1) */
  {"-",  1, OP_UNARY_MINUS,    1, ARG_NUMBER},
  {"+",  1, OP_UNARY_PLUS,     1, ARG_NUMBER},
  {"~",  1, OP_BITWISE_NOT,    1, ARG_INTEGER},
  {"!",  1, OP_LOGICAL_NOT,    1, ARG_INTEGER},

  /* Binary operators. It is important to the parsing in Th_Expr() that
   * the two-character symbols ("==") appear before the one-character
   * ones ("="). And that the priorities of all binary operators are
   * integers between 2 and 12.
   */
  {"<<", 2, OP_LEFTSHIFT,      4, ARG_INTEGER},
  {">>", 2, OP_RIGHTSHIFT,     4, ARG_INTEGER},
  {"<=", 2, OP_LE,             5, ARG_NUMBER},
  {">=", 2, OP_GE,             5, ARG_NUMBER},
  {"==", 2, OP_EQ,             6, ARG_NUMBER},
  {"!=", 2, OP_NE,             6, ARG_NUMBER},
  {"eq", 2, OP_SEQ,            7, ARG_STRING},
  {"ne", 2, OP_SNE,            7, ARG_STRING},
  {"&&", 2, OP_LOGICAL_AND,   11, ARG_INTEGER},
  {"||", 2, OP_LOGICAL_OR,    12, ARG_INTEGER},

  {"*",  1, OP_MULTIPLY,       2, ARG_NUMBER},
  {"/",  1, OP_DIVIDE,         2, ARG_NUMBER},
  {"%",  1, OP_MODULUS,        2, ARG_INTEGER},
  {"+",  1, OP_ADD,            3, ARG_NUMBER},
  {"-",  1, OP_SUBTRACT,       3, ARG_NUMBER},
  {"<",  1, OP_LT,             5, ARG_NUMBER},
  {">",  1, OP_GT,             5, ARG_NUMBER},
  {"&",  1, OP_BITWISE_AND,    8, ARG_INTEGER},
  {"^",  1, OP_BITWISE_XOR,    9, ARG_INTEGER},
  {"|",  1, OP_BITWISE_OR,    10, ARG_INTEGER},

  {0,0,0,0,0}
};

/*
** The first part of the string (zInput,nInput) contains an integer.
** Set *pnVarname to the number of bytes in the numeric string.
*/
static int thNextInteger(
  Th_Interp *interp,
  const char *zInput,
  int nInput,
  int *pnLiteral
){
  int i;
  int (*isdigit)(char) = th_isdigit;
  char c;

  if( nInput<2) return TH_ERROR;
  assert(zInput[0]=='0');
  c = zInput[1];
  if( c>='A' && c<='Z' ) c += 'a' - 'A';
  if( c=='x' ){
    isdigit = th_ishexdig;
  }else if( c!='o' && c!='b' ){
    return TH_ERROR;
  }
  for(i=2; i<nInput; i++){
    c = zInput[i];
    if( !isdigit(c) ){
      break;
    }
  }
  *pnLiteral = i;
  return TH_OK;
}

/*
** The first part of the string (zInput,nInput) contains a number.
** Set *pnVarname to the number of bytes in the numeric string.
*/
static int thNextNumber(
  Th_Interp *interp,
  const char *zInput,
  int nInput,
  int *pnLiteral
){
  int i = 0;
  int seenDot = 0;
  for(; i<nInput; i++){
    char c = zInput[i];
    if( (seenDot || c!='.') && !th_isdigit(c) ) break;
    if( c=='.' ) seenDot = 1;
  }
  *pnLiteral = i;
  return TH_OK;
}

/*
** Free an expression tree.
*/
static void exprFree(Th_Interp *interp, Expr *pExpr){
  if( pExpr ){
    exprFree(interp, pExpr->pLeft);
    exprFree(interp, pExpr->pRight);
    Th_Free(interp, pExpr->zValue);
    Th_Free(interp, pExpr);
  }
}

/*
** Evaluate an expression tree.
*/
static int exprEval(Th_Interp *interp, Expr *pExpr){
  int rc = TH_OK;

  if( pExpr->pOp==0 ){
    /* A literal */
    rc = thSubstWord(interp, pExpr->zValue, pExpr->nValue);
  }else{
    int eArgType = 0;           /* Actual type of arguments */

    /* Argument values */
    int iLeft = 0;
    int iRight = 0;
    double fLeft;
    double fRight;

    /* Left and right arguments as strings */
    char *zLeft = 0; int nLeft = 0;
    char *zRight = 0; int nRight = 0;

    /* Evaluate left and right arguments, if they exist. */
    if( pExpr->pLeft ){
      rc = exprEval(interp, pExpr->pLeft);
      if( rc==TH_OK ){
        zLeft = Th_TakeResult(interp, &nLeft);
      }
    }
    if( rc==TH_OK && pExpr->pRight ){
      rc = exprEval(interp, pExpr->pRight);
      if( rc==TH_OK ){
        zRight = Th_TakeResult(interp, &nRight);
      }
    }

    /* Convert arguments to their required forms. */
    if( rc==TH_OK ){
      eArgType = pExpr->pOp->eArgType;
      if( eArgType==ARG_NUMBER ){
        if( (zLeft==0 || TH_OK==Th_ToInt(0, zLeft, nLeft, &iLeft))
         && (zRight==0 || TH_OK==Th_ToInt(0, zRight, nRight, &iRight))
        ){
          eArgType = ARG_INTEGER;
        }else if(
          (zLeft && TH_OK!=Th_ToDouble(interp, zLeft, nLeft, &fLeft)) ||
          (zRight && TH_OK!=Th_ToDouble(interp, zRight, nRight, &fRight))
        ){
          /* A type error. */
          rc = TH_ERROR;
        }
      }else if( eArgType==ARG_INTEGER ){
        rc = Th_ToInt(interp, zLeft, nLeft, &iLeft);
        if( rc==TH_OK && zRight ){
          rc = Th_ToInt(interp, zRight, nRight, &iRight);
        }
      }
    }

    if( rc==TH_OK && eArgType==ARG_INTEGER ){
      int iRes = 0;
      switch( pExpr->pOp->eOp ) {
        case OP_MULTIPLY:     iRes = iLeft*iRight;  break;
        case OP_DIVIDE:
          if( !iRight ){
            Th_ErrorMessage(interp, "Divide by 0:", zLeft, nLeft);
            rc = TH_ERROR;
            goto finish;
          }
          iRes = iLeft/iRight;
          break;
        case OP_MODULUS:
          if( !iRight ){
            Th_ErrorMessage(interp, "Modulo by 0:", zLeft, nLeft);
            rc = TH_ERROR;
            goto finish;
          }
          iRes = iLeft%iRight;
          break;
        case OP_ADD:          iRes = iLeft+iRight;  break;
        case OP_SUBTRACT:     iRes = iLeft-iRight;  break;
        case OP_LEFTSHIFT:    iRes = iLeft<<iRight; break;
        case OP_RIGHTSHIFT:   iRes = iLeft>>iRight; break;
        case OP_LT:           iRes = iLeft<iRight;  break;
        case OP_GT:           iRes = iLeft>iRight;  break;
        case OP_LE:           iRes = iLeft<=iRight; break;
        case OP_GE:           iRes = iLeft>=iRight; break;
        case OP_EQ:           iRes = iLeft==iRight; break;
        case OP_NE:           iRes = iLeft!=iRight; break;
        case OP_BITWISE_AND:  iRes = iLeft&iRight;  break;
        case OP_BITWISE_XOR:  iRes = iLeft^iRight;  break;
        case OP_BITWISE_OR:   iRes = iLeft|iRight;  break;
        case OP_LOGICAL_AND:  iRes = iLeft&&iRight; break;
        case OP_LOGICAL_OR:   iRes = iLeft||iRight; break;
        case OP_UNARY_MINUS:  iRes = -iLeft;        break;
        case OP_UNARY_PLUS:   iRes = +iLeft;        break;
        case OP_BITWISE_NOT:  iRes = ~iLeft;        break;
        case OP_LOGICAL_NOT:  iRes = !iLeft;        break;
        default: assert(!"Internal error");
      }
      Th_SetResultInt(interp, iRes);
    }else if( rc==TH_OK && eArgType==ARG_NUMBER ){
      switch( pExpr->pOp->eOp ) {
        case OP_MULTIPLY: Th_SetResultDouble(interp, fLeft*fRight);    break;
        case OP_DIVIDE:
          if( fRight==0.0 ){
            Th_ErrorMessage(interp, "Divide by 0:", zLeft, nLeft);
            rc = TH_ERROR;
            goto finish;
          }
          Th_SetResultDouble(interp, fLeft/fRight);
          break;
        case OP_ADD:         Th_SetResultDouble(interp, fLeft+fRight); break;
        case OP_SUBTRACT:    Th_SetResultDouble(interp, fLeft-fRight); break;
        case OP_LT:          Th_SetResultInt(interp, fLeft<fRight);    break;
        case OP_GT:          Th_SetResultInt(interp, fLeft>fRight);    break;
        case OP_LE:          Th_SetResultInt(interp, fLeft<=fRight);   break;
        case OP_GE:          Th_SetResultInt(interp, fLeft>=fRight);   break;
        case OP_EQ:          Th_SetResultInt(interp, fLeft==fRight);   break;
        case OP_NE:          Th_SetResultInt(interp, fLeft!=fRight);   break;
        case OP_UNARY_MINUS: Th_SetResultDouble(interp, -fLeft);       break;
        case OP_UNARY_PLUS:  Th_SetResultDouble(interp, +fLeft);       break;
        default: assert(!"Internal error");
      }
    }else if( rc==TH_OK ){
      int iEqual = 0;
      assert( eArgType==ARG_STRING );
      if( nRight==nLeft && 0==memcmp(zRight, zLeft, nRight) ){
        iEqual = 1;
      }
      switch( pExpr->pOp->eOp ) {
        case OP_SEQ:       Th_SetResultInt(interp, iEqual); break;
        case OP_SNE:       Th_SetResultInt(interp, !iEqual); break;
        default: assert(!"Internal error");
      }
    }

   finish:

    Th_Free(interp, zLeft);
    Th_Free(interp, zRight);
  }

  return rc;
}

/*
** Create an expression tree from an array of tokens. If successful,
** the root of the tree is stored in apToken[0].
*/
int exprMakeTree(Th_Interp *interp, Expr **apToken, int nToken){
  int iLeft;
  int i;
  int jj;

  assert(nToken>0);
#define ISTERM(x) (apToken[x] && (!apToken[x]->pOp || apToken[x]->pLeft))

  for(jj=0; jj<nToken; jj++){
    if( apToken[jj]->pOp && apToken[jj]->pOp->eOp==OP_OPEN_BRACKET ){
      int nNest = 1;
      int iLeft = jj;

      for(jj++; jj<nToken; jj++){
        Operator *pOp = apToken[jj]->pOp;
        if( pOp && pOp->eOp==OP_OPEN_BRACKET ) nNest++;
        if( pOp && pOp->eOp==OP_CLOSE_BRACKET ) nNest--;
        if( nNest==0 ) break;
      }
      if( jj==nToken ){
        return TH_ERROR;
      }
      if( (jj-iLeft)>1 ){
        if( exprMakeTree(interp, &apToken[iLeft+1], jj-iLeft-1) ){
          return TH_ERROR;
        }
        exprFree(interp, apToken[jj]);
        exprFree(interp, apToken[iLeft]);
        apToken[jj] = 0;
        apToken[iLeft] = 0;
      }
    }
  }

  iLeft = 0;
  for(jj=nToken-1; jj>=0; jj--){
    if( apToken[jj] ){
      if( apToken[jj]->pOp && apToken[jj]->pOp->iPrecedence==1
       && iLeft>0 && ISTERM(iLeft) ){
        apToken[jj]->pLeft = apToken[iLeft];
        apToken[jj]->pLeft->pParent = apToken[jj];
        apToken[iLeft] = 0;
      }
      iLeft = jj;
    }
  }
  for(i=2; i<=12; i++){
    iLeft = -1;
    for(jj=0; jj<nToken; jj++){
      Expr *pToken = apToken[jj];
      if( apToken[jj] ){
        if( pToken->pOp && !pToken->pLeft && pToken->pOp->iPrecedence==i ){
          int iRight = jj+1;
          for(; !apToken[iRight] && iRight<nToken; iRight++);
          if( iRight==nToken || iLeft<0 || !ISTERM(iRight) || !ISTERM(iLeft) ){
            return TH_ERROR;
          }
          pToken->pLeft = apToken[iLeft];
          apToken[iLeft] = 0;
          pToken->pLeft->pParent = pToken;
          pToken->pRight = apToken[iRight];
          apToken[iRight] = 0;
          pToken->pRight->pParent = pToken;
        }
        iLeft = jj;
      }
    }
  }
  for(jj=1; jj<nToken; jj++){
    assert( !apToken[jj] || !apToken[0] );
    if( apToken[jj] ){
      apToken[0] = apToken[jj];
      apToken[jj] = 0;
    }
  }

  return TH_OK;
}

/*
** Parse a string containing a TH expression to a list of tokens.
*/
static int exprParse(
  Th_Interp *interp,        /* Interpreter to leave error message in */
  const char *zExpr,        /* Pointer to input string */
  int nExpr,                /* Number of bytes at zExpr */
  Expr ***papToken,         /* OUT: Array of tokens. */
  int *pnToken              /* OUT: Size of token array */
){
  int i;

  int rc = TH_OK;
  int nNest = 0;
  int nToken = 0;
  Expr **apToken = 0;

  for(i=0; rc==TH_OK && i<nExpr; ){
    char c = zExpr[i];
    if( th_isspace(c) ){                                /* White-space     */
      i++;
    }else{
      Expr *pNew = (Expr *)Th_Malloc(interp, sizeof(Expr));
      const char *z = &zExpr[i];

      switch (c) {
        case '0':
          if( thNextInteger(interp, z, nExpr-i, &pNew->nValue)==TH_OK ){
            break;
          }
          /* fall through */
        case '1': case '2': case '3': case '4': case '5':
        case '6': case '7': case '8': case '9':
          thNextNumber(interp, z, nExpr-i, &pNew->nValue);
          break;

        case '$':
          thNextVarname(interp, z, nExpr-i, &pNew->nValue);
          break;

        case '{': case '[': {
          thNextCommand(interp, z, nExpr-i, &pNew->nValue);
          break;
        }

        case '"': {
          int iEnd = i;
          while( ++iEnd<nExpr && zExpr[iEnd]!='"' ){
            if( zExpr[iEnd]=='\\' ) iEnd++;
          }
          if( iEnd<nExpr ){
            pNew->nValue = iEnd+1-i;
          }
          break;
        }

        default: {
          int j;
          const char *zOp;
          for(j=0; (zOp=aOperator[j].zOp); j++){
            int nOp = aOperator[j].nOp;
            int nRemain = nExpr - i;
            int isMatch = 0;
            if( nRemain>=nOp && 0==memcmp(zOp, &zExpr[i], nOp) ){
              isMatch = 1;
            }
            if( isMatch ){
              if( aOperator[j].eOp==OP_CLOSE_BRACKET ){
                nNest--;
              }else if( nRemain>nOp ){
                if( aOperator[j].eOp==OP_OPEN_BRACKET ){
                  nNest++;
                }
              }else{
                /*
                ** This is not really a match because this operator cannot
                ** legally appear at the end of the string.
                */
                isMatch = 0;
              }
            }
            if( nToken>0 && aOperator[j].iPrecedence==1 ){
              Expr *pPrev = apToken[nToken-1];
              if( !pPrev->pOp || pPrev->pOp->eOp==OP_CLOSE_BRACKET ){
                continue;
              }
            }
            if( isMatch ){
              pNew->pOp = &aOperator[j];
              i += nOp;
              break;
            }
          }
        }
      }

      if( pNew->pOp || pNew->nValue ){
        if( pNew->nValue ){
          /* A terminal. Copy the string value. */
          assert( !pNew->pOp );
          pNew->zValue = Th_Malloc(interp, pNew->nValue);
          memcpy(pNew->zValue, z, pNew->nValue);
          i += pNew->nValue;
        }
        if( (nToken%16)==0 ){
          /* Grow the apToken array. */
          Expr **apTokenOld = apToken;
          apToken = Th_Malloc(interp, sizeof(Expr *)*(nToken+16));
          memcpy(apToken, apTokenOld, sizeof(Expr *)*nToken);
        }

        /* Put the new token at the end of the apToken array */
        apToken[nToken] = pNew;
        nToken++;
      }else{
        Th_Free(interp, pNew);
        rc = TH_ERROR;
      }
    }
  }

  if( nNest!=0 ){
    rc = TH_ERROR;
  }

  *papToken = apToken;
  *pnToken = nToken;
  return rc;
}

/*
** Evaluate the string (zExpr, nExpr) as a Th expression. Store
** the result in the interpreter interp and return TH_OK if
** successful. If an error occurs, store an error message in
** the interpreter result and return an error code.
*/
int Th_Expr(Th_Interp *interp, const char *zExpr, int nExpr){
  int rc;                           /* Return Code */
  int i;                            /* Loop counter */

  int nToken = 0;
  Expr **apToken = 0;

  if( nExpr<0 ){
    nExpr = th_strlen(zExpr);
  }

  /* Parse the expression to a list of tokens. */
  rc = exprParse(interp, zExpr, nExpr, &apToken, &nToken);

  /* If the parsing was successful, create an expression tree from
  ** the parsed list of tokens. If successful, apToken[0] is set
  ** to point to the root of the expression tree.
  */
  if( rc==TH_OK ){
    rc = exprMakeTree(interp, apToken, nToken);
  }

  if( rc!=TH_OK ){
    Th_ErrorMessage(interp, "syntax error in expression: \"", zExpr, nExpr);
  }

  /* Evaluate the expression tree. */
  if( rc==TH_OK ){
    rc = exprEval(interp, apToken[0]);
  }

  /* Free memory allocated by exprParse(). */
  for(i=0; i<nToken; i++){
    exprFree(interp, apToken[i]);
  }
  Th_Free(interp, apToken);

  return rc;
}

/*
** Allocate and return a pointer to a new hash-table. The caller should
** (eventually) delete the hash-table by passing it to Th_HashDelete().
*/
Th_Hash *Th_HashNew(Th_Interp *interp){
  Th_Hash *p;
  p = Th_Malloc(interp, sizeof(Th_Hash));
  return p;
}

/*
** Iterate through all values currently stored in the hash table. Invoke
** the callback function xCallback for each entry. The second argument
** passed to xCallback is a copy of the fourth argument passed to this
** function.  The return value from the callback function xCallback is
** ignored.
*/
void Th_HashIterate(
  Th_Interp *interp,
  Th_Hash *pHash,
  int (*xCallback)(Th_HashEntry *pEntry, void *pContext),
  void *pContext
){
  int i;
  for(i=0; i<TH_HASHSIZE; i++){
    Th_HashEntry *pEntry;
    Th_HashEntry *pNext;
    for(pEntry=pHash->a[i]; pEntry; pEntry=pNext){
      pNext = pEntry->pNext;
      xCallback(pEntry, pContext);
    }
  }
}

/*
** Helper function for Th_HashDelete().  Always returns non-zero.
*/
static int xFreeHashEntry(Th_HashEntry *pEntry, void *pContext){
  Th_Free((Th_Interp *)pContext, (void *)pEntry);
  return 1;
}

/*
** Free a hash-table previously allocated by Th_HashNew().
*/
void Th_HashDelete(Th_Interp *interp, Th_Hash *pHash){
  if( pHash ){
    Th_HashIterate(interp, pHash, xFreeHashEntry, (void *)interp);
    Th_Free(interp, pHash);
  }
}

/*
** This function is used to insert or delete hash table items, or to
** query a hash table for an existing item.
**
** If parameter op is less than zero, then the hash-table element
** identified by (zKey, nKey) is removed from the hash-table if it
** exists. NULL is returned.
**
** Otherwise, if the hash-table contains an item with key (zKey, nKey),
** a pointer to the associated Th_HashEntry is returned. If parameter
** op is greater than zero, then a new entry is added if one cannot
** be found. If op is zero, then NULL is returned if the item is
** not already present in the hash-table.
*/
Th_HashEntry *Th_HashFind(
  Th_Interp *interp,
  Th_Hash *pHash,
  const char *zKey,
  int nKey,
  int op                      /* -ve = delete, 0 = find, +ve = insert */
){
  unsigned int iKey = 0;
  int i;
  Th_HashEntry *pRet;
  Th_HashEntry **ppRet;

  if( nKey<0 ){
    nKey = th_strlen(zKey);
  }

  for(i=0; i<nKey; i++){
    iKey = (iKey<<3) ^ iKey ^ zKey[i];
  }
  iKey = iKey % TH_HASHSIZE;

  for(ppRet=&pHash->a[iKey]; (pRet=*ppRet); ppRet=&pRet->pNext){
    assert( pRet && ppRet && *ppRet==pRet );
    if( pRet->nKey==nKey && 0==memcmp(pRet->zKey, zKey, nKey) ) break;
  }

  if( op<0 && pRet ){
    assert( ppRet && *ppRet==pRet );
    *ppRet = pRet->pNext;
    Th_Free(interp, pRet);
    pRet = 0;
  }

  if( op>0 && !pRet ){
    pRet = (Th_HashEntry *)Th_Malloc(interp, sizeof(Th_HashEntry) + nKey);
    pRet->zKey = (char *)&pRet[1];
    pRet->nKey = nKey;
    memcpy(pRet->zKey, zKey, nKey);
    pRet->pNext = pHash->a[iKey];
    pHash->a[iKey] = pRet;
  }

  return pRet;
}

/*
** This function is the same as the standard strlen() function, except
** that it returns 0 (instead of being undefined) if the argument is
** a null pointer.
*/
int th_strlen(const char *zStr){
  int n = 0;
  if( zStr ){
    while( zStr[n] ) n++;
  }
  return n;
}

/* Whitespace characters:
**
**     ' '    0x20
**     '\t'   0x09
**     '\n'   0x0A
**     '\v'   0x0B
**     '\f'   0x0C
**     '\r'   0x0D
**
** Whitespace characters have the 0x01 flag set. Decimal digits have the
** 0x2 flag set. Single byte printable characters have the 0x4 flag set.
** Alphabet characters have the 0x8 bit set. Hexadecimal digits have the
** 0x20 flag set.
**
** The special list characters have the 0x10 flag set
**
**    { } [ ] \ ; ' "
**
**    " 0x22
**
*/
static unsigned char aCharProp[256] = {
  0,  0,  0,  0,  0,  0,  0,  0,     0,  1,  1,  1,  1,  1,  0,  0,   /* 0x0. */
  0,  0,  1,  1,  0,  0,  0,  0,     0,  0,  0,  0,  0,  0,  0,  0,   /* 0x1. */
  5,  4, 20,  4,  4,  4,  4,  4,     4,  4,  4,  4,  4,  4,  4,  4,   /* 0x2. */
 38, 38, 38, 38, 38, 38, 38, 38,    38, 38,  4, 20,  4,  4,  4,  4,   /* 0x3. */
  4, 44, 44, 44, 44, 44, 44, 12,    12, 12, 12, 12, 12, 12, 12, 12,   /* 0x4. */
 12, 12, 12, 12, 12, 12, 12, 12,    12, 12, 12, 20, 20, 20,  4,  4,   /* 0x5. */
  4, 44, 44, 44, 44, 44, 44, 12,    12, 12, 12, 12, 12, 12, 12, 12,   /* 0x6. */
 12, 12, 12, 12, 12, 12, 12, 12,    12, 12, 12, 20,  4, 20,  4,  4,   /* 0x7. */

  0,  0,  0,  0,  0,  0,  0,  0,     0,  0,  0,  0,  0,  0,  0,  0,   /* 0x8. */
  0,  0,  0,  0,  0,  0,  0,  0,     0,  0,  0,  0,  0,  0,  0,  0,   /* 0x9. */
  0,  0,  0,  0,  0,  0,  0,  0,     0,  0,  0,  0,  0,  0,  0,  0,   /* 0xA. */
  0,  0,  0,  0,  0,  0,  0,  0,     0,  0,  0,  0,  0,  0,  0,  0,   /* 0xB. */
  0,  0,  0,  0,  0,  0,  0,  0,     0,  0,  0,  0,  0,  0,  0,  0,   /* 0xC. */
  0,  0,  0,  0,  0,  0,  0,  0,     0,  0,  0,  0,  0,  0,  0,  0,   /* 0xD. */
  0,  0,  0,  0,  0,  0,  0,  0,     0,  0,  0,  0,  0,  0,  0,  0,   /* 0xE. */
  0,  0,  0,  0,  0,  0,  0,  0,     0,  0,  0,  0,  0,  0,  0,  0    /* 0xF. */
};

/*
** Clone of the standard isspace() and isdigit function/macros.
*/
int th_isspace(char c){
  return (aCharProp[(unsigned char)c] & 0x01);
}
int th_isdigit(char c){
  return (aCharProp[(unsigned char)c] & 0x02);
}
int th_isspecial(char c){
  return (aCharProp[(unsigned char)c] & 0x11);
}
int th_isalnum(char c){
  return (aCharProp[(unsigned char)c] & 0x0A);
}
int th_isalpha(char c){
  return (aCharProp[(unsigned char)c] & 0x08);
}
int th_ishexdig(char c){
  return (aCharProp[(unsigned char)c] & 0x20);
}
int th_isoctdig(char c){
  return ((c|7) == '7');
}
int th_isbindig(char c){
  return ((c|1) == '1');
}

#ifndef LONGDOUBLE_TYPE
# define LONGDOUBLE_TYPE long double
#endif


/*
** Return TRUE if z is a pure numeric string.  Return FALSE if the
** string contains any character which is not part of a number. If
** the string is numeric and contains the '.' character, set *realnum
** to TRUE (otherwise FALSE).
**
** An empty string is considered non-numeric.
*/
static int sqlite3IsNumber(const char *z, int *realnum){
  int incr = 1;
  if( *z=='-' || *z=='+' ) z += incr;
  if( !th_isdigit(*(u8*)z) ){
    return 0;
  }
  z += incr;
  if( realnum ) *realnum = 0;
  while( th_isdigit(*(u8*)z) ){ z += incr; }
  if( *z=='.' ){
    z += incr;
    if( !th_isdigit(*(u8*)z) ) return 0;
    while( th_isdigit(*(u8*)z) ){ z += incr; }
    if( realnum ) *realnum = 1;
  }
  if( *z=='e' || *z=='E' ){
    z += incr;
    if( *z=='+' || *z=='-' ) z += incr;
    if( !th_isdigit(*(u8*)z) ) return 0;
    while( th_isdigit(*(u8*)z) ){ z += incr; }
    if( realnum ) *realnum = 1;
  }
  return *z==0;
}

/*
** The string z[] is an ascii representation of a real number.
** Convert this string to a double.
**
** This routine assumes that z[] really is a valid number.  If it
** is not, the result is undefined.
**
** This routine is used instead of the library atof() function because
** the library atof() might want to use "," as the decimal point instead
** of "." depending on how locale is set.  But that would cause problems
** for SQL.  So this routine always uses "." regardless of locale.
*/
static int sqlite3AtoF(const char *z, double *pResult){
  int sign = 1;
  const char *zBegin = z;
  LONGDOUBLE_TYPE v1 = 0.0;
  while( th_isspace(*(u8*)z) ) z++;
  if( *z=='-' ){
    sign = -1;
    z++;
  }else if( *z=='+' ){
    z++;
  }
  while( th_isdigit(*(u8*)z) ){
    v1 = v1*10.0 + (*z - '0');
    z++;
  }
  if( *z=='.' ){
    LONGDOUBLE_TYPE divisor = 1.0;
    z++;
    while( th_isdigit(*(u8*)z) ){
      v1 = v1*10.0 + (*z - '0');
      divisor *= 10.0;
      z++;
    }
    v1 /= divisor;
  }
  if( *z=='e' || *z=='E' ){
    int esign = 1;
    int eval = 0;
    LONGDOUBLE_TYPE scale = 1.0;
    z++;
    if( *z=='-' ){
      esign = -1;
      z++;
    }else if( *z=='+' ){
      z++;
    }
    while( th_isdigit(*(u8*)z) ){
      eval = eval*10 + *z - '0';
      z++;
    }
    while( eval>=64 ){ scale *= 1.0e+64; eval -= 64; }
    while( eval>=16 ){ scale *= 1.0e+16; eval -= 16; }
    while( eval>=4 ){ scale *= 1.0e+4; eval -= 4; }
    while( eval>=1 ){ scale *= 1.0e+1; eval -= 1; }
    if( esign<0 ){
      v1 /= scale;
    }else{
      v1 *= scale;
    }
  }
  *pResult = sign<0 ? -v1 : v1;
  return z - zBegin;
}

/*
** Try to convert the string passed as arguments (z, n) to an integer.
** If successful, store the result in *piOut and return TH_OK.
**
** If the string cannot be converted to an integer, return TH_ERROR.
** If the interp argument is not NULL, leave an error message in the
** interpreter result too.
*/
int Th_ToInt(Th_Interp *interp, const char *z, int n, int *piOut){
  int i = 0;
  int iOut = 0;
  int base = 10;
  int (*isdigit)(char) = th_isdigit;

  if( n<0 ){
    n = th_strlen(z);
  }

  if( n>1 && (z[0]=='-' || z[0]=='+') ){
    i = 1;
  }
  if( (n-i)>2 && z[i]=='0' ){
    if( z[i+1]=='x' || z[i+1]=='X' ){
      i += 2;
      base = 16;
      isdigit = th_ishexdig;
    }else if( z[i+1]=='o' || z[i+1]=='O' ){
      i += 2;
      base = 8;
      isdigit = th_isoctdig;
    }else if( z[i+1]=='b' || z[i+1]=='B' ){
      i += 2;
      base = 2;
      isdigit = th_isbindig;
    }
  }
  for(; i<n; i++){
    char c = z[i];
    if( !isdigit(c) ){
      Th_ErrorMessage(interp, "expected integer, got: \"", z, n);
      return TH_ERROR;
    }
    if( c>='a' ){
      c -= 'a'-10;
    }else if( c>='A' ){
      c -= 'A'-10;
    }else{
      c -= '0';
    }
    iOut = iOut * base + c;
  }

  if( n>0 && z[0]=='-' ){
    iOut *= -1;
  }

  *piOut = iOut;
  return TH_OK;
}

/*
** Try to convert the string passed as arguments (z, n) to a double.
** If successful, store the result in *pfOut and return TH_OK.
**
** If the string cannot be converted to a double, return TH_ERROR.
** If the interp argument is not NULL, leave an error message in the
** interpreter result too.
*/
int Th_ToDouble(
  Th_Interp *interp,
  const char *z,
  int n,
  double *pfOut
){
  if( !sqlite3IsNumber((const char *)z, 0) ){
    Th_ErrorMessage(interp, "expected number, got: \"", z, n);
    return TH_ERROR;
  }

  sqlite3AtoF((const char *)z, pfOut);
  return TH_OK;
}

/*
** Set the result of the interpreter to the th1 representation of
** the integer iVal and return TH_OK.
*/
int Th_SetResultInt(Th_Interp *interp, int iVal){
  int isNegative = 0;
  char zBuf[32];
  char *z = &zBuf[32];

  if( iVal<0 ){
    isNegative = 1;
    iVal = iVal * -1;
  }
  *(--z) = '\0';
  *(--z) = (char)(48+((unsigned)iVal%10));
  while( (iVal = ((unsigned)iVal/10))>0 ){
    *(--z) = (char)(48+((unsigned)iVal%10));
    assert(z>zBuf);
  }
  if( isNegative ){
    *(--z) = '-';
  }

  return Th_SetResult(interp, z, -1);
}

/*
** Set the result of the interpreter to the th1 representation of
** the double fVal and return TH_OK.
*/
int Th_SetResultDouble(Th_Interp *interp, double fVal){
  int i;                /* Iterator variable */
  double v = fVal;      /* Input value */
  char zBuf[128];       /* Output buffer */
  char *z = zBuf;       /* Output cursor */
  int iDot = 0;         /* Digit after which to place decimal point */
  int iExp = 0;         /* Exponent (NN in eNN) */
  const char *zExp;     /* String representation of iExp */

  /* Precision: */
  #define INSIGNIFICANT 0.000000000001
  #define ROUNDER       0.0000000000005
  double insignificant = INSIGNIFICANT;

  /* If the real value is negative, write a '-' character to the
   * output and transform v to the corresponding positive number.
   */
  if( v<0.0 ){
    *z++ = '-';
    v *= -1.0;
  }

  /* Normalize v to a value between 1.0 and 10.0. Integer
   * variable iExp is set to the exponent. i.e the original
   * value is (v * 10^iExp) (or the negative thereof).
   */
  if( v>0.0 ){
    while( (v+ROUNDER)>=10.0 ) { iExp++; v *= 0.1; }
    while( (v+ROUNDER)<1.0 )   { iExp--; v *= 10.0; }
  }
  v += ROUNDER;

  /* For a small (<12) positive exponent, move the decimal point
   * instead of using the "eXX" notation.
   */
  if( iExp>0 && iExp<12 ){
    iDot = iExp;
    iExp = 0;
  }

  /* For a small (>-4) negative exponent, write leading zeroes
   * instead of using the "eXX" notation.
   */
  if( iExp<0 && iExp>-4 ){
    *z++ = '0';
    *z++ = '.';
    for(i=0; i>(iExp+1); i--){
      *z++ = '0';
    }
    iDot = -1;
    iExp = 0;
  }

  /* Output the digits in real value v. The value of iDot determines
   * where (if at all) the decimal point is placed.
   */
  for(i=0; i<=(iDot+1) || v>=insignificant; i++){
    *z++ = (char)(48 + (int)v);
    v = (v - ((double)(int)v)) * 10.0;
    insignificant *= 10.0;
    if( iDot==i ){
      *z++ = '.';
    }
  }

  /* If the exponent is not zero, add the "eXX" notation to the
   * end of the string.
   */
  if( iExp!=0 ){
    *z++ = 'e';
    Th_SetResultInt(interp, iExp);
    zExp = Th_GetResult(interp, 0);
    for(i=0; zExp[i]; i++){
      *z++ = zExp[i];
    }
  }

  *z = '\0';
  return Th_SetResult(interp, zBuf, -1);
}

/*
** Appends all currently registered command names to the specified list
** and returns TH_OK upon success.  Any other return value indicates an
** error.
*/
int Th_ListAppendCommands(
  Th_Interp *interp,      /* Interpreter context */
  char **pzList,          /* OUT: List of command names */
  int *pnList             /* OUT: Number of command names */
){
  Th_InterpAndList *p = (Th_InterpAndList *)Th_Malloc(
    interp, sizeof(Th_InterpAndList)
  );
  p->interp = interp;
  p->pzList = pzList;
  p->pnList = pnList;
  Th_HashIterate(interp, interp->paCmd, thListAppendHashKey, p);
  Th_Free(interp, p);
  return TH_OK;
}

/*
** Appends all variable names for the current frame to the specified list
** and returns TH_OK upon success.  Any other return value indicates an
** error.  If the current frame cannot be obtained, TH_ERROR is returned.
*/
int Th_ListAppendVariables(
  Th_Interp *interp,      /* Interpreter context */
  char **pzList,          /* OUT: List of variable names */
  int *pnList             /* OUT: Number of variable names */
){
  Th_Frame *pFrame = getFrame(interp, 0);
  if( pFrame ){
    Th_InterpAndList *p = (Th_InterpAndList *)Th_Malloc(
      interp, sizeof(Th_InterpAndList)
    );
    p->interp = interp;
    p->pzList = pzList;
    p->pnList = pnList;
    Th_HashIterate(interp, pFrame->paVar, thListAppendHashKey, p);
    Th_Free(interp, p);
    return TH_OK;
  }else{
    return TH_ERROR;
  }
}

/*
** Appends all array element names for the specified array variable to the
** specified list and returns TH_OK upon success.  Any other return value
** indicates an error.
*/
int Th_ListAppendArray(
  Th_Interp *interp,      /* Interpreter context */
  const char *zVar,       /* Pointer to variable name */
  int nVar,               /* Number of bytes at nVar */
  char **pzList,          /* OUT: List of array element names */
  int *pnList             /* OUT: Number of array element names */
){
  Th_Variable *pValue = thFindValue(interp, zVar, nVar, 0, 1, 1, 0);
  if( pValue && !pValue->zData && pValue->pHash ){
    Th_InterpAndList *p = (Th_InterpAndList *)Th_Malloc(
      interp, sizeof(Th_InterpAndList)
    );
    p->interp = interp;
    p->pzList = pzList;
    p->pnList = pnList;
    Th_HashIterate(interp, pValue->pHash, thListAppendHashKey, p);
    Th_Free(interp, p);
  }else{
    *pzList = 0;
    *pnList = 0;
  }
  return TH_OK;
}