This file is indexed.

/usr/lib/python2.7/dist-packages/swap/query.py is in python-swap 1.2.1-7.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   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
""" Query for cwm architecture

2003-09-07 split off from llyn.py
"""

QL_NS = "http://www.w3.org/2004/ql#"
from sparql2cwm import SPARQL_NS

from set_importer import Set, ImmutableSet, sorted

from RDFSink import Logic_NS, RDFSink, forSomeSym, forAllSym
from RDFSink import CONTEXT, PRED, SUBJ, OBJ, PARTS, ALL4
from RDFSink import N3_nil, N3_first, N3_rest, OWL_NS, N3_Empty, N3_List, List_NS
from RDFSink import RDF_NS_URI

from OrderedSequence import intersection, minus, indentString

import diag
from diag import chatty_flag, tracking, progress
from term import BuiltIn, LightBuiltIn, RDFBuiltIn, ArgumentNotLiteral, \
    HeavyBuiltIn, Function, ReverseFunction, MultipleFunction, \
    MultipleReverseFunction, UnknownType, Env, \
    Literal, Symbol, Fragment, FragmentNil,  Term, \
    CompoundTerm, List, EmptyList, NonEmptyList, ErrorFlag
from formula import StoredStatement, Formula
from why import Because, BecauseBuiltIn, BecauseOfRule, \
    BecauseOfExperience, becauseSubexpression, Reason, \
    BecauseSupports, BecauseMerge ,report, Premise, newTopLevelFormula, isTopLevel


BuiltinFeedError = (ArgumentNotLiteral, UnknownType)

import types
import sys
# from sets import Set  # only in python 2.3 and following
                        # set_importer does a cleaner job

INFINITY = 1000000000           # @@ larger than any number occurences


# State values as follows, high value=try first:
S_UNKNOWN =     99  # State unknown - to be [re]calculated by setup.
S_DONE =        80  # Exhausted all possible ways to saitsfy this. return now.
S_LIGHT_UNS_READY= 70  # Light, not searched yet, but can run
S_LIGHT_GO =    65  # Light, can run  Do this!
S_NOT_LIGHT =   60  # Not a light built-in, haven't searched yet.
S_LIGHT_EARLY=  50  # Light built-in, not ready to calculate, not searched yet.
S_NEED_DEEP=    45  # Can't search because of unbound compound term,
                    #   could do recursive unification
S_HEAVY_READY=  40  # Heavy built-in, search done,
                    #    but formula now has no vars left. Ready to run.
S_LIGHT_WAIT=   30  # Light built-in, not enough constants to calculate, search done.
S_HEAVY_WAIT=   20  # Heavy built-in, too many variables in args to calculate, search done.
S_REMOTE =      10  # Waiting for local query to be resolved as much as possible
#S_SATISFIED =   0  # Item has been staisfied, and is no longer a constraint, continue with others

stateName = { 
    S_UNKNOWN : "????",
    S_DONE :        "DONE",
    S_LIGHT_UNS_READY : "LtUsGo",
    S_LIGHT_GO : "LtGo",
    S_NOT_LIGHT : "NotLt",
    S_LIGHT_EARLY : "LtEarly",
    S_NEED_DEEP :  "Deep",
    S_HEAVY_READY :   "HvGo",
    S_LIGHT_WAIT : "LtWait",
    S_HEAVY_WAIT : "HvWait",
    S_REMOTE :   "Remote"}
#    S_SATISFIED:          "Satis" }





def think(knowledgeBase, ruleFormula=None, mode="", why=None):
    """Forward-chaining inference
    
    In the case in which rules are added back into the
    store. The store is used for read (normally canonical) and write
    (normally open) at the samne time.  It in fact has to be open.
    """
    if ruleFormula == None:
        ruleFormula = knowledgeBase
    assert knowledgeBase.canonical == None , "Must be open to add stuff:"+ `knowledgeBase `

    if diag.chatty_flag > 45: progress("think: rules from %s added to %s" %(
                                        knowledgeBase, ruleFormula))
    return InferenceTask(knowledgeBase, ruleFormula, mode=mode, why=why, repeat=1).run()

def applyRules(
                workingContext,    # Data we assume 
                ruleFormula = None,    # Where to find the rules
                targetContext = None):   # Where to put the conclusions
    """Once"""
    t = InferenceTask(workingContext, ruleFormula, targetContext)
    result = t.run()
    del(t)
    return result

def applyQueries(
                workingContext,    # Data we assume 
                ruleFormula = None,    # Where to find the rules
                targetContext = None):   # Where to put the conclusions
    """Once, nothing recusive, for a N3QL query"""
    t = InferenceTask(workingContext, ruleFormula, targetContext)
    t.gatherQueries(t.ruleFormula)
    result = t.runSmart()
    del(t)
    return result


def applySparqlQueries(
                workingContext,    # Data we assume 
                ruleFormula = None,    # Where to find the rules
                targetContext = None):   # Where to put the conclusions
    """Once, nothing recusive, for a N3QL query"""
    t = InferenceTask(workingContext, ruleFormula, targetContext, mode="q")
    t.gatherSparqlQueries(t.ruleFormula)
    result = t.runSmart()
    del(t)
    return result

class InferenceTask:
    """A task of applying rules or filters to information"""
    def __init__(self,
                workingContext,    # Data we assume 
                ruleFormula = None,    # Where to find the rules
                targetContext = None,   # Where to put the conclusions
                universals = Set(),        # Inherited from higher contexts
                mode="",                # modus operandi
                why=None,                       # Trace reason for all this
                repeat = 0):            # do it until finished
        """ Apply rules in one context to the same or another
    
        A rule here is defined by log:implies, which associates the template
        (aka premise, precondidtion, antecedent, body) to the conclusion
        (aka postcondition, head).
        """
        if diag.chatty_flag >20:
            progress("New Inference task, rules from %s" % ruleFormula)
        if targetContext is None: targetContext = workingContext # return new data to store
        if ruleFormula is None: self.ruleFormula = workingContext # apply own rules
        else: self.ruleFormula = ruleFormula
        self.ruleFor = {}
        self.hasMetaRule = 0

        self.workingContext, self.targetContext, self.mode, self.repeat = \
            workingContext, targetContext, mode, repeat
        self.store = self.workingContext.store

    def runSmart(self):
        """Run the rules by mapping rule interactions first"""
        rules= self.ruleFor.values()
        if self.targetContext is self.workingContext: #otherwise, there cannot be loops
            for r1 in rules:
                vars1 = r1.templateExistentials | r1.variablesUsed
                for r2 in rules:
                    vars2 = r2.templateExistentials | r2.variablesUsed
                    for s1 in r1.conclusion.statements:
                        s2 = None
                        p = None        
                        for s2 in r2.template.statements:
                            for p in PRED, SUBJ, OBJ:
                                if ((s1[p] not in vars1
                                        and not isinstance(s1[p], CompoundTerm))
                                    and (s2[p] not in vars2
                                        and not isinstance(s2[p], CompoundTerm))
                                    and (s1[p] is not s2[p])):
                                        break
                            else:
                                r1.affects[r2] = 1 # save transfer binding here?
                                if diag.chatty_flag > 20: progress(
                                    "%s can affect %s because %s can trigger %s" %
                                                (`r1`, `r2`, `s1`, `s2`))
                                break # can affect

                        else:  # that statement couldn't but
                            if diag.chatty_flag > 96:
                                progress("...couldn't beccause of ",s1,s2,p)
                            continue # try next one
                        break # can

        # Calculate transitive closure of "affects"
        for r1 in rules:
            r1.traceForward(r1)  # could lazy eval

        for r1 in rules:
            r1.indirectlyAffects.sort()
            r1.indirectlyAffectedBy.sort()
            
        # Print the affects matrix
        if diag.chatty_flag > 30:
            str = "%4s:" % "Aff"
            for r2 in rules:
                str+= "%4s" % `r2`
            progress(str)
            for r1 in rules:
                str= "%4s:" % `r1`
                for r2 in rules:
                    if r2.affects.get(r1, 0): str+= "%4s" % "X"
                    elif r1 in r2.indirectlyAffects: str +="%4s" % "-"
                    else: str+= "%4s" % " "
                progress(str)
            
        # Find cyclic subsystems
        # These are connected sets within which you can get from any node back to itself
        pool = rules[:]
        pool.sort()  # Sorted list, can use merge, intersection, etc
        cyclics = []
        while pool:
            r1 = pool[0]
            if r1 not in r1.indirectlyAffects:
                cyclic = [ r1 ]
                pool.remove(r1)
            else:
                if diag.chatty_flag > 90:
                    progress("%s indirectly affects %s and is affected by %s" %
                        (r1, r1.indirectlyAffects, r1.indirectlyAffectedBy))
                cyclic = intersection(r1.indirectlyAffects, r1.indirectlyAffectedBy)
                pool = minus(pool, cyclic)
            cyclics.append(CyclicSetOfRules(cyclic))
            if diag.chatty_flag > 90:
                progress("New cyclic: %s" % cyclics[-1])
            

        # Because the cyclic subsystems contain any loops, we know
        # there are no cycles between them. Therefore, there is a partial
        # ordering.  If we order them in that way, then we can resolve each
        # one just once without violating

        pool = cyclics[:]
        seq = []
        while pool:
            cy = pool[0] #  pick random one
            seq = partialOrdered(cy, pool) + seq

        if diag.chatty_flag > 10:
            progress("In order:" + `seq`)

        # TEMPORARY: test that
        n = len(seq)
        for i in range(n):
            for j in range(i-1):
                if compareCyclics(seq[i], seq[j]) < 0:
                    raise RuntimeError("Should not be:  %s < %s" %(seq[i], seq[j]))

        # Run the rules
        total = 0
        for cy in seq:
            total += cy.run()
        if diag.chatty_flag > 9:
            progress("Grand total %i facts found" % total)
        return total


    def run(self):
        """Perform task.
        Return number of  new facts"""
        self.gatherRules(self.ruleFormula)
        if self.hasMetaRule or not self.repeat:
            return self.runLaborious()
        return self.runSmart()

    def runLaborious(self):
        """Perform task.
        Return number of  new facts.
        Start again if new rule mayhave been generated."""
        grandtotal = 0
        iterations = 0
        self.ruleFor = {}
        needToCheckForRules = 1
        while 1:
            if needToCheckForRules:
                self.gatherRules(self.ruleFormula)
                needToCheckForRules = 0
            _total = 0
            iterations = iterations + 1
            for rule in self.ruleFor.values():
                found = rule.once()
                if (diag.chatty_flag >50):
                    progress( "Laborious: Found %i new stmts on for rule %s" %
                                                            (found, rule))
                _total = _total+found
                if found and (rule.meta or self.targetContext._closureMode):
                    needToCheckForRules = 1
            if diag.chatty_flag > 5: progress(
                "Total of %i new statements on iteration %i." %
                    (_total, iterations))
            if _total == 0: break
            grandtotal= grandtotal + _total
            if not self.repeat: break
        if diag.chatty_flag > 5: progress(
                "Grand total of %i new statements in %i iterations." %
                    (grandtotal, iterations))
        return grandtotal


    def gatherRules(self, ruleFormula):
        universals = Set() # @@ self.universals??
        for s in ruleFormula.statementsMatching(pred=self.store.implies):
            r = self.ruleFor.get(s, None)
            if r != None: continue
            con, pred, subj, obj  = s.quad
            if (isinstance(subj, Formula)
                and isinstance(obj, Formula)):
                v2 = universals | ruleFormula.universals() # Note new variables can be generated
                r = Rule(self, antecedent=subj, consequent=obj, statement=s,  variables=v2)
                self.ruleFor[s] = r
                if r.meta: self.hasMetaRule = 1
                if (diag.chatty_flag >30):
                    progress( "Found rule %r for statement %s " % (r, s))

        for F in ruleFormula.each(pred=self.store.implies, obj=self.store.Truth): #@@ take out when --closure=T ??
            self.gatherRules(F)  #See test/rules13.n3, test/schema-rules.n3 etc

    def gatherQueries(self, ruleFormula):
        "Find a set of rules in N3QL"
        universals = Set() # @@ self.universals??
        ql_select = self.store.newSymbol(QL_NS + "select")
        ql_where = self.store.newSymbol(QL_NS + "where")
        for s in ruleFormula.statementsMatching(pred=ql_select):
            r = self.ruleFor.get(s, None)
            if r != None: continue
            con, pred, query, selectClause  = s.quad
            whereClause= ruleFormula.the(subj=query, pred=ql_where)
            if whereClause == None: continue # ignore (warning?)
            
            if (isinstance(selectClause, Formula)
                and isinstance(whereClause, Formula)):
                v2 = universals | ruleFormula.universals() # Note new variables can be generated
                r = Rule(self, antecedent=whereClause, consequent=selectClause,
                                statement=s,  variables=v2)
                self.ruleFor[s] = r
                if r.meta: self.hasMetaRule = 1
                if (diag.chatty_flag >30):
                    progress( "Found rule %r for statement %s " % (r, s))

    def gatherSparqlQueries(self, ruleFormula):
        "Find the rules in SPARQL"
        store = self.store
        sparql = store.newSymbol(SPARQL_NS)
        
        for from_statement in ruleFormula.statementsMatching(pred=sparql['data']):
            working_context_stand_in = from_statement.object()
            ruleFormula = ruleFormula.substitution({working_context_stand_in: self.workingContext})
        query_root = ruleFormula.any(pred=store.type, obj=sparql['ConstructQuery'])
        if not query_root:
            # This is wrong
            query_root = ruleFormula.any(pred=store.type, obj=sparql['SelectQuery'])
        if not query_root:
            query_root = ruleFormula.any(pred=store.type, obj=sparql['AskQuery'])
        # query_root is a very boring bNode
        if query_root:
            #construct query
            for where_triple in ruleFormula.statementsMatching(subj=query_root, pred=sparql['where']):
                where_clause = where_triple.object()
                #where_clause is the tail of the rule
                implies_clause = ruleFormula.the(subj=where_clause, pred=store.implies)
                assert implies_clause is not None, ("where=%s, f=%s" % (where_clause.debugString(), ruleFormula.debugString()))
                #implies_clause is the head of the rule
                v2 = ruleFormula.universals().copy()
                r = Rule(self, antecedent=where_clause, consequent=implies_clause,
                         statement=where_triple, variables=v2)
                self.ruleFor[where_triple] = r
                if r.meta: self.hasMetaRule = 1
                if (diag.chatty_flag >30):
                    progress( "Found rule %r for statement %s " % (r, where_triple))


def partialOrdered(cy1, pool):
    """Return sequence conforming to the partially order in a set of cyclic subsystems
    
    Basially, we find the dependencies of a node and remove them from the pool.
    Then, any node in the pool can be done earlier, because has no depndency from those done.
    """
    seq = []
    for r1 in cy1:   # @@ did just chose first rule cy[0], but didn't get all
        for r2 in  r1.affects:
            if r2 not in cy1:  # An external dependency
                cy2 = r2.cycle
                if cy2 in pool:
                    seq = partialOrdered(cy2, pool) + seq
    pool.remove(cy1)
    if diag.chatty_flag > 90: progress("partial topo: %s" % `[cy1] + seq`)
    return [cy1] + seq

class CyclicSetOfRules:
    """A set of rules which are connected
    """
    def __init__(self, rules):
        self.rules = rules
        for r1 in rules:
            r1.cycle = self

    def __getitem__(self, i):
        return self.rules[i]

    def __repr__(self):
        return `self.rules`

    def run(self):
        "Run a cyclic subset of the rules"
        if diag.chatty_flag > 20:
            progress()
            progress("Running cyclic system %s" % (self))
        if len(self.rules) == 1:
            rule = self.rules[0]
            if not rule.affects.get(rule, 0):
#               rule.already = None # Suppress recording of previous answers
                # - no, needed to remove dup bnodes as in test/includes/quant-implies.n3 --think
                # When Rule.once is smarter about not iterating over things not mentioned elsewhere,
                # can remove this.
                return rule.once()
                
        agenda = self.rules[:]
        total = 0
        for r1 in self.rules:
            af = r1.affects.keys()
            af.sort()
            r1.affectsInCyclic = intersection(self.rules, af)
        while agenda:
            rule = agenda[0]
            agenda = agenda[1:]
            found = rule.once()
            if diag.chatty_flag > 20: progress("Rule %s gave %i. Affects:%s." %(
                        rule, found, rule.affectsInCyclic))
            if found:
                total = total + found
                for r2 in rule.affectsInCyclic:
                    if r2 not in agenda:
                        if diag.chatty_flag > 30: progress("...rescheduling", r2)
                        agenda.append(r2)
        if diag.chatty_flag > 20: progress("Cyclic subsystem exhausted")
        return total
        

def buildPattern(workingContext, template):
    """Make a list of unmatched statements including special
    builtins to check something is universally quantified"""
    unmatched = template.statements[:]
    for v in template.occurringIn(template.universals()):
        if diag.chatty_flag > 100: progress(
            "Template %s has universalVariableName %s, formula is %s" % (template, v, template.debugString()))
        unmatched.append(StoredStatement((workingContext,
                template.store.universalVariableName,
                workingContext,
                v
#               workingContext.store.newLiteral(v.uriref())
                                          )))
    return unmatched

def buildStrictPattern(workingContext, template):
    unmatched = buildPattern(workingContext, template)
    for v in template.occurringIn(template.existentials()):
        if diag.chatty_flag > 100: progress(
            "Tempate %s has existentialVariableName %s, formula is %s" % (template, v, template.debugString()))
        unmatched.append(StoredStatement((workingContext,
                template.store.existentialVariableName,
                workingContext,
                v
#               workingContext.store.newLiteral(v.uriref())
                                          )))
##    for v in template.variables():
##      if diag.chatty_flag > 100: progress(
##          "Tempate %s has enforceUniqueBinding %s, formula is %s" % (template, v, template.debugString()))
##      unmatched.append(StoredStatement((workingContext,
##              template.store.enforceUniqueBinding,
##                v,
##              workingContext.store.newLiteral(v.uriref())
##                                          )))
    return unmatched
    
nextRule = 0
class Rule:

    def __init__(self, task, antecedent, consequent, statement, variables):
        """Try a rule
        
        Beware lists are corrupted. Already list is updated if present.
        The idea is that, for a rule which may be tried many times, the constant 
        processing is done in this rather than in Query().
        
        The already dictionary is used to track bindings.
        This less useful when not repeating (as in --filter), but as in fact
        there may be several ways in which one cane get the same bindings,
        even without a repeat.
        """
        global nextRule
        self.task = task
        self.template = antecedent
        self.conclusion = consequent
        self.store = self.template.store
        self.statement = statement      #  original statement
        self.number = nextRule = nextRule+1
        self.meta = self.conclusion.contains(pred=self.conclusion.store.implies) #generate rules?
#       if task.repeat: self.already = []    # No neat to track dups if not 
#       else: self.already = None
        self.already = []
        self.affects = {}
        self.indirectlyAffects = []
        self.indirectlyAffectedBy = []
        self.affectsInCyclic = []
        self.cycle = None
        
        # When the template refers to itself, the thing we are
        # are looking for will refer to the context we are searching
        # Similarly, references to the working context have to be moved into the
        # target context when the conclusion is drawn.
    
    
#       if self.template.universals() != Set():
#           raise RuntimeError("""Cannot query for universally quantified things.
#           As of 2003/07/28 forAll x ...x cannot be on left hand side of rule.
#           This/these were: %s\n""" % self.template.universals())
    
        self.unmatched = buildPattern(task.workingContext, self.template)
        self.templateExistentials = self.template.existentials().copy()
        _substitute({self.template: task.workingContext}, self.unmatched)
    
        variablesMentioned = self.template.occurringIn(variables)
        self.variablesUsed = self.conclusion.occurringIn(variablesMentioned)
        for x in variablesMentioned:
            if x not in self.variablesUsed:
                self.templateExistentials.add(x)
        if diag.chatty_flag >20:
            progress("New Rule %s ============ looking for:" % `self` )
            for s in self.template.statements: progress("    ", `s`)
            progress("=>")
            for s in self.conclusion.statements: progress("    ", `s`)
            progress("Universals declared in outer " + seqToString(variables))
            progress(" mentioned in template       " + seqToString(variablesMentioned))
            progress(" also used in conclusion     " + seqToString(self.variablesUsed))
            progress("Existentials in template     " + seqToString(self.templateExistentials))
        return

    def once(self):
        if diag.chatty_flag >20:
            progress("Trying rule %s ===================" % self )
            progress( setToString(self.unmatched))
        task = self.task
        query = Query(self.store,
                        unmatched = self.unmatched[:],
                        template = self.template,
                        variables = self.variablesUsed.copy(),
                        existentials = self.templateExistentials.copy(),
                        workingContext = task.workingContext,
                        conclusion = self.conclusion,
                        targetContext = task.targetContext,
                        already = self.already,
                      ###
                        rule = self.statement,
                      ###
                        interpretBuiltins = 1,    # (...)
                        meta = task.workingContext,
                        mode = task.mode)
        Formula.resetRenames()
        total = query.resolve()
        Formula.resetRenames(False)
        if diag.chatty_flag > 20:
            progress("Rule try generated %i new statements" % total)
        return total
    
    def __repr__(self):
        if self in self.affects: return "R"+`self.number`+ "*"
        return "R"+`self.number`

    def compareByAffects(other):
        if other in self.indirectlyAffects: return -1  # Do me earlier
        if other in self.indirectlyAffectedBy: return 1
        return 0
        

    def traceForward(self, r1):
        for r2 in r1.affects:
            if r2 not in self.indirectlyAffects:
                self.indirectlyAffects.append(r2)
                r2.indirectlyAffectedBy.append(self)
                self.traceForward(r2)
#           else:
#               self.__setattr__("leadsToCycle", 1)
    
def testIncludes(f, g, _variables=Set(),  bindings={}, interpretBuiltins = 0):
    """Return whether or nor f contains a top-level formula equvalent to g.
    Just a test: no bindings returned."""
    if diag.chatty_flag >30: progress("testIncludes ============\nseeing if %s entails %s" % (f, g))
#    raise RuntimeError()
    if not(isinstance(f, Formula) and isinstance(g, Formula)): return 0

    assert f.canonical is f, f.debugString()
    assert g.canonical is g
    m = diag.chatty_flag
    diag.chatty_flag = 0
    if m > 60: progress("Before rename: ", f.debugString())
    f = f.renameVars()
    if m > 60: progress("After rename: ", f.debugString())
    diag.chatty_flag = m
    if diag.chatty_flag >100: progress("Formula we are searching in is\n%s" % g.debugString())
    unmatched = buildPattern(f, g)
    templateExistentials = g.existentials()
    more_variables = g.universals().copy()
    _substitute({g: f}, unmatched)
    
#    if g.universals() != Set():
#       raise RuntimeError("""Cannot query for universally quantified things.
#       As of 2003/07/28 forAll x ...x cannot be on left hand side of rule.
#       This/these were: %s\n""" % g.universals())

#    if bindings != {}: _substitute(bindings, unmatched)

    if diag.chatty_flag > 20:
        progress( "# testIncludes BUILTIN, %i terms in template %s, %i unmatched, %i template variables" % (
            len(g.statements),
            `g`[-8:], len(unmatched), len(templateExistentials)))
        if diag.chatty_flag > 80:
            for v in _variables:
                progress( "    Variable: " + `v`[-8:])

    result = Query(f.store,
                unmatched=unmatched,
                template = g,
                variables=Set(),
                interpretBuiltins = interpretBuiltins,
                existentials=_variables | templateExistentials | more_variables,
                justOne=1, mode="").resolve()

    if diag.chatty_flag >30: progress("=================== end testIncludes =" + `result`)
    return result


def n3Equivalent(g, f, env1, env2, vars=Set([]),
                 universals=Set(), existentials=Set([]),
                 n1Source=42, n2Source=42):    
    """Return whether or nor f contains a top-level formula equvalent to g.
    Just a test: no bindings returned."""
    if diag.chatty_flag >30: progress("Query.py n3Equivalent ============\nseeing if %s equals %s" % (f, g))
#    raise RuntimeError()
    if not(isinstance(f, Formula) and isinstance(g, Formula)): pass
    elif f is g:
        yield env1, env2
    elif len(f) > len(g):
        pass
    else:

        assert f.canonical is f, "%s, %s" % (f.debugString(), f.canonical.debugString())
        assert g.canonical is g, "%s, %s" % (g.debugString(), g.canonical.debugString())

        m = diag.chatty_flag
        diag.chatty_flag = 0
        if m > 60: progress("Before rename: ", f.debugString())
        f = f.renameVars()
        if m > 60: progress("After rename: ", f.debugString())
        diag.chatty_flag = m
        unmatched = buildStrictPattern(f, g)
        templateExistentials = g.existentials() | g.universals() | existentials
        more_variables = Set(vars)
        _substitute({g: f}, unmatched)
        
        if env1: _substitute(env1.asDict(), unmatched)

        if diag.chatty_flag > 20:
            progress( "# testEqual BUILTIN, %i terms in template %s, %i unmatched, %i template variables" % (
                len(g.statements),
                `g`[-8:], len(unmatched), len(templateExistentials)))
            if diag.chatty_flag > 80:
                for v in vars:
                    progress( "    Variable: " + `v`[-8:])

        result = Query(f.store,
                    unmatched=unmatched,
                    template = g,
                    variables=more_variables,
                    workingContext = f,
                    interpretBuiltins = False,
                    existentials= templateExistentials ,
                    justReturn=1, mode="").resolve()

        if diag.chatty_flag >30: progress("=================== end n3Equivalent =" + `result`)
        if not result: result = []
        for x in result:
            for k, (v, source) in x.items():
                env1 = env1.bind(k, (v, env2.id))
            yield env1, env2
##    return [(x, None) for x in result]



############################################################## Query engine
#
# Template matching in a graph
#
# Optimizations we have NOT done:
#   - storing the tree of bindings so that we don't have to duplicate them another time
#   - using that tree to check only whether new data would extend it (very cool - memory?)
#      (this links to dynamic data, live variables.)
#   - recognising in advance disjoint graph templates, doing cross product of separate searches
#
# Built-Ins:
#   The trick seems to be to figure out which built-ins are going to be faster to
# calculate, and so should be resolved before query terms involving a search, and
# which, like those involving recursive queries or net access, will be slower than a query term,
# and so should be left till last.
#   I feel that it should be possible to argue about built-ins just like anything else,
# so we do not exclude these things from the query system. We therefore may have both light and
# heavy built-ins which still have too many variables to calculate at this stage.
# When we do the variable substitution for new bindings, these can be reconsidered.


class Queue([].__class__):
    __slots__ = ['statements', 'bNodes']
    list = [].__class__

    def __init__(self, other=[], metaSource = None):
        self.list.__init__(self, other)
        if isinstance(metaSource, Queue):
            for k in self.__slots__:
                setattr(self, k, getattr(metaSource, k).copy())
        else:
            self.statements = Set()
            self.bNodes = Set()
            pass #fill in slots here

    def popBest(self):
        best = len(self) -1 # , say...
        i = best - 1
        while i >=0:
            if (self[i].state > self[best].state
                or (self[i].state == self[best].state
                    and self[i].short < self[best].short)): best=i
            i = i - 1                
        item = self[best]
        self.remove(item)
        return item

    def __repr__(self):
        return 'Queue(%s, bNodes=%s)' % (list.__repr__(self), self.bNodes)

#Queue = [].__class__

class Chain_Step(object):
    def __init__(self, vars, existentials, queue, env, parent=None, evidence=[]):
        self.vars = vars
        self.existentials = existentials
        self.lines = queue
        self.env = env
        assert parent is None
        self.parent = parent
        self.evidence = evidence

    def popBest(self):
        return self.lines.popBest()

    def copy(self):
        retVal = self.__class__(self.vars, self.existentials, self.lines, self.env, self.parent, self.evidence)
        return retVal

    def done(self):
        return not self.lines

    def __cmp__(self, other):
        return cmp(len(other.lines), len(self.lines))

    def __repr__(self):
        return "%s(lines=%r,\n\tenv=%r,\n\tparent=%r,\n\tevidence=%r)" % (self.__class__.__name__, self.lines, self.env, self.parent, self.evidence)


def returnWrapper(f):
    def g(*args, **keywords):
        retVal = f(*args, **keywords)
        progress('%s() returns %s' % (f.func_name, retVal))
        return retVal
    return g

class Query(Formula):
    """A query holds a hypothesis/antecedent/template which is being matched aginst (unified with)
    the knowledge base."""
    def __init__(self,
               store,
               unmatched=[],           # Tuple of interned quads we are trying to match CORRUPTED
               template = None,         # Actually, must have one
               variables=Set(),           # List of variables to match and return CORRUPTED
               existentials=Set(),        # List of variables to match to anything
                                    # Existentials or any kind of variable in subexpression
               workingContext = None,
               conclusion = None,
               targetContext = None,
               already = None,      # Dictionary of matches already found
               rule = None,                 # The rule statement
               interpretBuiltins = 0,        # List of contexts in which to use builtins
               justOne = 0,         # Flag: Stop when you find the first one
               justReturn = 0,      # Flag: Return bindings, don't conclude
               mode = "",           # Character flags modifying modus operandi
            meta = None):           # Context to check for useful info eg remote stuff

        
        if diag.chatty_flag > 50:
            progress( "Query: created with %i terms. (justone=%i, wc=%s)" % 
                    (len(unmatched), justOne, workingContext))
            if diag.chatty_flag > 80: progress( setToString(unmatched))
            if diag.chatty_flag > 90 and interpretBuiltins: progress(
                "iBuiltIns=1 ")

        Formula.__init__(self, store)
        self.statements = Queue()   #  Unmatched with more info
#       self.store = store      # Initialized by Formula
        self.variables = variables
        self._existentialVariables = existentials
        self.workingContext = workingContext
        self.conclusion = conclusion
        self.targetContext = targetContext
        self.justOne = justOne
        self.already = already
        self.rule = rule
        self.template = template  # For looking for lists
        self.meta = meta
        self.mode = mode
        self.lastCheckedNumberOfRedirections = 0
        self.bindingList = []
        self.justReturn = justReturn
        realMatchCount = 0
        if justReturn and not variables:
            self.justOne = True
        for quad in unmatched:
            item = QueryItem(self, quad)
            if not item.setup(allvars=variables|existentials, unmatched=unmatched,
                        interpretBuiltins=interpretBuiltins, mode=mode):
                if diag.chatty_flag > 80: progress(
                                    "match: abandoned, no way for "+`item`)
                self.noWay = 1
                return  # save time
            if not item.builtIn:
                realMatchCount += 1    
            self.statements.append(item)
        if justReturn and realMatchCount > len(workingContext):
            self.noWay = 1
            return
        return
        
    def resolve(self):
        if hasattr(self, "noWay"): return 0
        k = self.matchFormula(self.statements, self.variables, self._existentialVariables)
        if self.justReturn:
            return self.bindingList
        return k

    def checkRedirectsInAlready(self):
        """Kludge"""
        n = len(self.targetContext._redirections)
        if n  > self.lastCheckedNumberOfRedirections:
            self.lastCheckedNumberOfRedirections = n
            self.redirect(self.targetContext._redirections)
            
    def redirect(self, redirections):
        for bindings in self.already:
            for var, value in bindings.items():
                try:
                    x = redirections[value]
                except:
                    pass
                else:
                    if diag.chatty_flag>29: progress("Redirecting binding %r to %r" % (value, x))
                    bindings[var] = x

    def conclude(self, bindings, evidence = [], extraBNodes = Set(), allBindings=None):
        """When a match found in a query, add conclusions to target formula.

        Returns the number of statements added."""
        if self.justOne:
            self.bindingList = [{}]
            return 1   # If only a test needed
        if self.justReturn:
            if bindings not in self.bindingList:
#                progress('CONCLUDE bindings = %s' % bindings)
                self.bindingList.append(bindings)
            return 1

        if diag.chatty_flag >60:
                        progress( "Concluding tentatively...%r" % bindings)
        if self.already != None:
            self.checkRedirectsInAlready() # @@@ KLUDGE - use delegation and notification systme instead
            if bindings in self.already:
                if diag.chatty_flag > 30:
                    progress("@@ Duplicate result: %r is in %r" %  (bindings, self.already))
                return 0
            if diag.chatty_flag > 30: progress("Not duplicate: %r" % bindings)
            self.already.append(bindings)
        else: 
            if diag.chatty_flag >60:
                        progress( "No duplication check")
        
        if diag.tracking:
            if allBindings is None:
                allBindings = bindings
            for loc in xrange(len(evidence)):
                r = evidence[loc]
                
                if isinstance(r, BecauseSupportsWill):                    
                    evidence[loc] = BecauseSupports(*([smarterSubstitution(k, allBindings,
                        r.args[1], why=Because("I support it: "), exception=[r.args[2]]) for k in r.args] +
                        [[k for k in evidence if isinstance(k, (StoredStatement, Reason))]]))
                if isinstance(r, BecauseBuiltInWill):
                    evidence[loc] = BecauseBuiltIn(*[smarterSubstitution(k, allBindings,
                        r.args[0], why=Because("I include it: " + k.debugString() + `allBindings`)) for k in r.args[1:]])
            reason = BecauseOfRule(self.rule, bindings=allBindings, knownExistentials = extraBNodes,
                            evidence=evidence, kb=self.workingContext)
#           progress("We have a reason for %s of %s with bindings %s" % (self.rule, reason, alBindings))
        else:
            reason = None

        es, exout = (self.workingContext.existentials() | extraBNodes), Set() #self.workingContext.existentials() | 
        for var, (val, source) in bindings.items():
            if isinstance(val, Exception):
                if "q" in self.mode: # How nice are we?
                    raise ValueError(val)
                return 0
            intersection = val.occurringIn(es) #  Take time for large number of bnodes?
            if intersection:   
                exout.update(intersection)
                if diag.chatty_flag > 25: progress(
                "Match found to that which is only an existential: %s -> %s" %
                                                    (var, val))
                for val2 in intersection:
                    if val not in self.targetContext.existentials():
                        if self.conclusion.occurringIn([var]):
                            self.targetContext.declareExistential(val2)

        # Variable renaming

        b2 = bindings.asDict()
#        b2[self.conclusion] = self.targetContext  # What does this mean?
        ok = self.targetContext.universals() 
        # It is actually ok to share universal variables with other stuff
        poss = self.conclusion.universals().copy()
        for x in poss.copy():
            if x in ok: poss.remove(x)
        poss_sorted = list(poss)
        poss_sorted.sort(Term.compareAnyTerm)
        #progress(poss)

#        vars = self.conclusion.existentials() + poss  # Terms with arbitrary identifiers
#        clashes = self.occurringIn(targetContext, vars)    Too slow to do every time; play safe
        if diag.chatty_flag > 25:
            s=""
        for v in poss_sorted:
            v2 = self.targetContext.newUniversal()
            b2[v] =v2   # Regenerate names to avoid clash
            if diag.chatty_flag > 25: s = s + ",uni %s -> %s" %(v, v2)
        for v in sorted(list(self.conclusion.existentials()), Term.compareAnyTerm):
            if v not in exout:
                v2 = self.targetContext.newBlankNode()
                b2[v] =v2   # Regenerate names to avoid clash
                if diag.chatty_flag > 25: s = s + ",exi %s -> %s" %(v, v2)
            else:
                if diag.chatty_flag > 25: s = s + (", (%s is existential in kb)"%v)
        if diag.chatty_flag > 25:
            progress("Variables regenerated: universal " + `poss`
                + " existential: " +`self.conclusion.existentials()` + s)
        

        if diag.chatty_flag>19:
            progress("Concluding DEFINITELY" + bindingsToString(b2) )
        before = self.store.size
        _, delta = self.targetContext.loadFormulaWithSubstitution(
                    self.conclusion, b2, why=reason, cannon=True)
        if diag.chatty_flag>29 and delta:
            progress(" --- because of: %s => %s, with bindings %s" % (self.template.debugString(),
                                                                      self.conclusion.debugString(),
                                                                      b2))
        if diag.chatty_flag> 40:
            progress("Added %i, nominal size of store changed from %i to %i."%(delta, before, self.store.size))
        return delta #  self.store.size - before


##################################################################################

    def matchFormula(query, queue, variables, existentials, env=Env()):
        total = 0
        stack = [Chain_Step(variables, existentials, queue, env)]
        while stack:
            if diag.chatty_flag > 150:
                progress(stack)
            workingStep = stack.pop()
            if not workingStep.done():
                queue = workingStep.lines
                evidence = workingStep.evidence
                bindings = workingStep.env
                variables = workingStep.vars
                existentials = workingStep.existentials
                
                item = workingStep.popBest()

                con, pred, subj, obj = item.quad
                state = item.state
                if state == S_DONE:  # After bindNew, could be undoable.
                    nbs = []
                elif state == S_LIGHT_UNS_READY:          # Search then 
                    nbs = item.tryBuiltin(queue, bindings, evidence=evidence)
                    item.state = S_LIGHT_EARLY   # Unsearched, try builtin @@@@@@@@@ <== need new state here
                elif state == S_LIGHT_GO:
                    nbs = item.tryBuiltin(queue, bindings, evidence=evidence)
                    item.state = S_DONE   # Searched.
                elif (state == S_LIGHT_EARLY or state == S_NOT_LIGHT or
                                        state == S_NEED_DEEP): #  Not searched yet
                    nbs = item.tryDeepSearch(queue, bindings)
                elif state == S_HEAVY_READY:  # not light, may be heavy; or heavy ready to run
                    if pred is query.store.includes: # and not diag.tracking:  # don't optimize when tracking?
                        variables = variables.copy()
                        existentials = existentials.copy()
                        nbs = item.doIncludes(queue, existentials, variables, bindings)
                    elif pred is query.store.supports:
                        variables = variables.copy()
                        existentials = existentials.copy()
                        nbs = item.doSupports(queue, existentials, variables, bindings)
                    else:
                        item.state = S_HEAVY_WAIT  # Assume can't resolve
                        nbs = item.tryBuiltin(queue, bindings, evidence=evidence)
                    item.state = S_DONE
                elif state == S_REMOTE: # Remote query -- need to find all of them for the same service
                    items = [item]
                    for i in queue[:]:
                        if i.state == S_REMOTE and i.service is item.service: #@@ optimize which group is done first!
                            items.append(i)
                            queue.remove(i)
                    nbs = query.remoteQuery(items)
                    item.state = S_DONE  # do not put back on list
                elif state ==S_HEAVY_WAIT or state == S_LIGHT_WAIT:
                    if item.quad[PRED] is query.store.universalVariableName or \
                       item.quad[PRED] is query.store.existentialVariableName:
                        ### We will never bind this variable in the first place
                        item.state = S_DONE
                        nbs = []
                    else:
                        if diag.chatty_flag > 20 :
                            progress("@@@@ Warning: query can't find term which will work.")
                            progress( "   state is %s, queue length %i" % (state, len(queue)+1))
                            progress("@@ Current item: %s" % `item`)
                            progress(queueToString(queue))
                        continue  # Forget it
                else:
                    raise RuntimeError, "Unknown state " + `state`


                stack_extent = []
                for nb, reason in nbs:
                    assert isinstance(nb, dict), nb
                    q2 = Queue([], queue)
                    if query.justReturn:
                        ### What does the following do?
                        ### If we are doing a 1::1 match, record everything we have matched
                        if isinstance(reason, StoredStatement):
                            if reason not in q2.statements and \
                               reason[CONTEXT] is query.workingContext:
                                q2.statements.add(reason)
                            else:
                                continue
                    if isinstance(reason, StoredStatement):
                        if True or reason[CONTEXT] is not query.workingContext:
                            for m in nb.values():
                                if isinstance(m, tuple):
                                    m = m[0]
                                if m in reason[CONTEXT].existentials():
                                    q2.bNodes.add(m)
                                    if diag.chatty_flag > 80:
                                        ### These get picked up from log:includes
                                        ### {[:b :c]} log:includes {?X :b :c} ...
                                        progress('Adding bNode %s, now %s' % (m, q2.bNodes))
                    new_thing = False
                    try:
                        new_env = bindings.flatten(nb)
                    except ValueError:
                        pass
                    else:
                        new_thing = True
                    for i in queue:
                        newItem = i.clone()
                        newItem.bindNew(new_env) ## Is this right? I was hoping to avoid this
                        q2.append(newItem)  #@@@@@@@@@@  If exactly 1 binding, loop (tail recurse)
                    if new_thing:
                        if diag.chatty_flag > 70:
                            progress("query.py bindings nb new_entry:", bindings, nb, new_env)
                        new_step = Chain_Step(variables, existentials, q2, new_env, workingStep.parent, workingStep.evidence + [reason])
                        stack_extent.append(new_step)

                if item.state != S_DONE:
                    queue.append(item)
                    new_step = workingStep.copy()
                    stack_extent.append(new_step)
                stack.extend(stack_extent)

                    

            else:
                if workingStep.parent is not None:
                    raise RuntimeError("We are not chaining yet.\n How did I get here?")
                else:
                    total = query.conclude(workingStep.env.filter(workingStep.vars), allBindings=workingStep.env
                                          , evidence=workingStep.evidence, extraBNodes = workingStep.lines.bNodes) + total  # No terms left .. success!
                    #raise RuntimeError("I need to conclude here, workingStep=%s" % workingStep)
                    pass
        return total


    def matchFormula2(query,
               queue,               # Set of items we are trying to match CORRUPTED
               variables,           # List of variables to match and return CORRUPTED
               existentials,        # List of variables to match to anything
                                    # Existentials or any kind of variable in subexpression
               bindings = Env(),       # Bindings discovered so far
               newBindings = Env(),    # New bindings not yet incorporated
               evidence = []):      # List of statements supporting the bindings so far
        """ Iterate on the remaining query items
    bindings      collected matches already found
    newBindings  matches found and not yet applied - used in recursion
    
    You probably really need the state diagram to understand this
    http://www.w3.org/2000/10/swap/doc/states.svg
    even if it is a bit out of date.
        """
        total = 0
        assert isinstance(bindings, Env)
        assert isinstance(newBindings, Env), 'env is an %s, not an %s' % (newBindings.__class__, Env)
        if diag.chatty_flag > 59:
            progress( "QUERY2: called %i terms, %i bindings %s, (new: %s)" %
                      (len(queue), len(bindings), `bindings`,
                       `newBindings`))
            if diag.chatty_flag > 90: progress( queueToString(queue))

        newBindingItems = newBindings.items()
        while newBindingItems:   # Take care of business left over from recursive call
            pair = newBindingItems.pop(0)
            if isinstance(pair[1], tuple):
                pair = (pair[0], pair[1][0])
            else:
                raise RuntimeError
            if diag.chatty_flag>95: progress("    new binding:  %s -> %s" % (`pair[0]`, `pair[1]`))
            if pair[0] in variables:
                variables.remove(pair[0])
                bindings = bindings.newBinding(pair[0], (pair[1], None))
            else:      # Formulae aren't needed as existentials, unlike lists. hmm.
                ### bindings.update({pair[0]: pair[1]})  # remove me!!!!!
#               if diag.tracking: raise RuntimeError(pair[0], pair[1])
                #bindings.update({pair[0]: pair[1]})  # Record for proof only
                if pair[0] not in existentials:
                    if isinstance(pair[0], List):
                        # pair[0] should be a variable, can't be a list, surely
                        del newBindings[pair[0]]
                        #We can accidently bind a list using (1 2 3) rdf:rest (?x 3).
                        #This finds the true binding
                        reallyNewBindingsList = pair[0].unify(
                                    pair[1], bindings, Env(), variables | existentials)
                        ## I'm a bit parenoid. If we did not find a binding ...
                        if not reallyNewBindingsList or not hasattr(
                                        reallyNewBindingsList, '__iter__'):
                            return 0
                        reallyNewBindingsList = [x for x in reallyNewBindingsList]
                        try:
                            reallyNewBindings = reallyNewBindingsList[0][0] #We don't deal
                            # with multiple ways to bind
                        except:
                            print 'we lost'
                            print pair[0], pair[1]
                            a = pair[0].unify(
                                    pair[1], variables, existentials, bindings)
                            print a
                            print a[0]
                            print a[0][0]
                            raise
                        newBindingItems.extend(reallyNewBindings.items())
                        newBindings = newBindings.update2(reallyNewBindings)
                    else:
                        if diag.chatty_flag > 40:  # Reasonable
                            progress("Not in existentials or variables but now bound:", `pair[0]`)
                elif diag.tracking: bindings = bindings.newBinding(pair[0], (pair[1], None))
                if not isinstance(pair[0], CompoundTerm) and ( # Hack - else rules13.n3 fails @@
                    pair[0] in existentials):    # Hack ... could be bnding from nested expression
                    existentials.remove(pair[0]) # Can't match anything anymore, need exact match

        # Perform the substitution, noting where lists become boundLists.
        # We do this carefully, messing up the order only of things we have already processed.
        if newBindings != {}:
            for item in queue:
                if item.bindNew(newBindings) == 0: return 0


        while len(queue) > 0:

            if (diag.chatty_flag > 90):
                progress( "query iterating with %i terms, %i bindings: %s; %i new bindings: %s ." %
                          (len(queue),
                           len(bindings),bindingsToString(bindings),
                           len(newBindings),bindingsToString(newBindings)))
                progress ( queueToString(queue))


            # Take best.  (Design choice: search here or keep queue in order)
            # item = queue.pop()
            item = queue.popBest()
            
            if diag.chatty_flag>49:
                progress( "Looking at " + `item`)
                progress( "...with vars("+seqToString(variables)+")"
                         + " ExQuVars:("+seqToString(existentials)+")")
            con, pred, subj, obj = item.quad
            state = item.state
            if state == S_DONE:  # After bindNew, could be undoable.
                return total # Forget it -- must be impossible
            if state == S_LIGHT_UNS_READY:              # Search then 
                nbs = item.tryBuiltin(queue, bindings, evidence=evidence)
                item.state = S_LIGHT_EARLY   # Unsearched, try builtin @@@@@@@@@ <== need new state here
            elif state == S_LIGHT_GO:
                nbs = item.tryBuiltin(queue, bindings, evidence=evidence)
                item.state = S_DONE   # Searched.
            elif (state == S_LIGHT_EARLY or state == S_NOT_LIGHT or
                                    state == S_NEED_DEEP): #  Not searched yet
                nbs = item.tryDeepSearch(queue, Env())
            elif state == S_HEAVY_READY:  # not light, may be heavy; or heavy ready to run
                if pred is query.store.includes: # and not diag.tracking:  # don't optimize when tracking?
                    nbs = item.doIncludes(queue, existentials, variables, bindings)
                elif pred is query.store.supports:
                    nbs = item.doSupports(queue, existentials, variables, bindings)
                else:
                    item.state = S_HEAVY_WAIT  # Assume can't resolve
                    nbs = item.tryBuiltin(queue, bindings, evidence=evidence)
                item.state = S_DONE
            elif state == S_REMOTE: # Remote query -- need to find all of them for the same service
                items = [item]
                for i in queue[:]:
                    if i.state == S_REMOTE and i.service is item.service: #@@ optimize which group is done first!
                        items.append(i)
                        queue.remove(i)
                nbs = query.remoteQuery(items)
                item.state = S_DONE  # do not put back on list
            elif state ==S_HEAVY_WAIT or state == S_LIGHT_WAIT:
                if item.quad[PRED] is query.store.universalVariableName or \
                   item.quad[PRED] is query.store.existentialVariableName:
                    ### We will never bind this variable in the first place
                    item.state = S_DONE
                    nbs = []
                else:
                    if diag.chatty_flag > 20 :
                        progress("@@@@ Warning: query can't find term which will work.")
                        progress( "   state is %s, queue length %i" % (state, len(queue)+1))
                        progress("@@ Current item: %s" % `item`)
                        progress(queueToString(queue))
                    return total  # Forget it
            else:
                raise RuntimeError, "Unknown state " + `state`
                
            if diag.chatty_flag > 90: progress("nbs=" + `nbs`)
            
#     query.py  Removed as I added this and wasn't sure whether it works with justReturn change below -tbl
#           # Optimization when sucess but no bindings
#           if (len(nbs) == 1 and nbs[0][0] == {} and nbs[0][1] is None and # if nbs == [({}, None)] and
#                   state == S_DONE):
#               if diag.chatty_flag>90: progress("LOOP to next, state="+`state`)
#               continue # Loop around and do the next one. optimization.

            for nb, reason in nbs:
                assert isinstance(nb,types.DictType), nb
                q2 = Queue([], queue)
                if query.justReturn:
                    ### What does the following do?
                    ### If we are doing a 1::1 match, record everything we have matched
                    if isinstance(reason, StoredStatement):
                        if reason not in q2.statements and \
                           reason[CONTEXT] is query.workingContext:
                            q2.statements.add(reason)
                        else:
                            continue
                if isinstance(reason, StoredStatement):
                    if True or reason[CONTEXT] is not query.workingContext:
                        for m in nb.values():
                            if isinstance(m, tuple):
                                m = m[0]
                            if m in reason[CONTEXT].existentials():
                                q2.bNodes.add(m)
                                if diag.chatty_flag > 80:
                                    ### These get picked up from log:includes
                                    ### {[:b :c] log:includes {?X :b :c} ...
                                    progress('Adding bNode %s, now %s' % (m, q2.bNodes))
                for i in queue:
                    newItem = i.clone()
                    q2.append(newItem)  #@@@@@@@@@@  If exactly 1 binding, loop (tail recurse)
                found = query.matchFormula(q2, variables.copy(), existentials.copy(),
                        bindings.copy(), nb, evidence = evidence + [reason])

                if diag.chatty_flag > 91: progress(
                    "Nested query returns %i (nb= %r)" % (found, nb))
                total = total + found
                if query.justOne and total:
                    return total

# NO - more to do return total # The called recursive calls above will have generated the output @@@@ <====XXXX
            if diag.chatty_flag > 80: progress("Item state %i, returning total %i" % (item.state, total))
            if (item.state == S_DONE):
                return total

            queue.append(item)
            # And loop back to take the next item

        if diag.chatty_flag>50: progress("QUERY MATCH COMPLETE with bindings: " + `bindings`)
        if query.justReturn:
            try:
                len(queue.statements)
                len(query.workingContext)
            except:
                print type(queue.statements)
                print type(query.workingContext)
                raise
            if len(queue.statements) != len(query.workingContext):
                return total
        newTotal = query.conclude(bindings,  evidence=evidence, extraBNodes = queue.bNodes, allBindings=bindings) + total  # No terms left .. success!
        if total:
            progress('newTotal=%s, total=%s' % (newTotal, total))
            raise RuntimeError('How did I get here?')
        return newTotal

    def remoteQuery(query, items):
        """Perform remote query as client on remote store
        Currently  this only goes to an SQL store, but should later use SPARQL etc
        in remote HTTP/SOAP call."""
        
        if diag.chatty_flag > 90:
            progress("    Remote service %s" % (items))
        serviceURI = items[0].service.uri
        if serviceURI.startswith("http:"):
            from sparql.sparqlClient import SparqlQuery
            return SparqlQuery(query, items, serviceURI)
        elif not serviceURI.startswith("mysql:"):
            raise ValueError("Unknown URI scheme for remote query service: %s" % serviceURI)
            
        import dbork.SqlDB
        from dbork.SqlDB import ResultSet, SqlDBAlgae, ShowStatement

        # SqlDB stores results in a ResultSet.
        rs = ResultSet()
        # QueryPiece qp stores query tree.
        qp = rs.buildQuerySetsFromCwm(items, query.variables, query._existentialVariables)
        # Extract access info from the first item.
        if diag.chatty_flag > 90:
            progress("    Remote service %s" %items[0].service.uri)
        (user, password, host, database) = re.match(
                "^mysql://(?:([^@:]+)(?::([^@]+))?)@?([^/]+)/([^/]+)/$",
                items[0].service.uri).groups()
        # Look for one of a set of pre-compiled rdb schemas.
        HostDB2SchemeMapping = { "mysql://root@localhost/w3c" : "AclSqlObjects" }
        if (HostDB2SchemeMapping.has_key(items[0].service.uri)):
            cachedSchema = HostDB2SchemeMapping.get(items[0].service.uri)
        else:
            cachedSchema = None
        # The SqlDBAlgae object knows how to compile SQL query from query tree qp.
        a = SqlDBAlgae(query.store.symbol(items[0].service.uri), cachedSchema,
            user, password, host, database, query.meta, query.store.pointsAt,
            query.store)
        # Execute the query.
        messages = []
        nextResults, nextStatements = a._processRow([], [], qp, rs, messages, {})
        # rs.results = nextResults # Store results as initial state for next use of rs.
        if diag.chatty_flag > 90: progress(string.join(messages, "\n"))
        if diag.chatty_flag > 90: progress("query matrix \"\"\""+
                        rs.toString({'dataFilter' : None})+"\"\"\" .\n")

        nbs = []
        reason = Because("Remote query") # could be messages[0] which is the query
        # Transform nextResults to format cwm expects.
        for resultsRow in nextResults:
            boundRow = {}
            for i in range(len(query.variables)):
                v = query.variables[i]
                index = rs.getVarIndex(v)
                interned = resultsRow[index]
                boundRow[v] = interned  # bindings
            nbs.append((boundRow, reason))

        if diag.chatty_flag > 10: progress("====> bindings from remote query:"+`nbs`)
        return nbs   # No bindings for testing

class BetterNone(object):
    __slots__ = []
    def __new__(cls):
        try:
            return cls.__val__
        except:
            cls.__val__ = object.__new__(cls)
        return cls.__val__
    def __hash__(self):
        raise TypeError
    def __str__(self):
        raise NotImplementedError
    def __eq__(self, other):
        raise NotImplementedError
    __neq__ = __eq__
    __lt__ = __gt__ = __leq__ = __geq__ = __eq__
BNone = BetterNone()

             
class QueryItem(StoredStatement):  # Why inherit? Could be useful, and is logical...
    """One line in a query being resolved.
    
    To a large extent, each line can keep track of its own state.
    When a remote query is done, query lines to the same server have to be coordinated again.
    """
    def __init__(self, query, quad):
        quad = lookupQuad(quad[CONTEXT]._redirections, quad)
        #print quad[CONTEXT]._redirections
        self.quad = quad
        self.query = query
        self.searchPattern = None # Will be list of variables
        self.store = query.store
        self.state = S_UNKNOWN  # Invalid
        self.short = INFINITY
        self.neededToRun = None   # see setup()
        self.myIndex = None     # will be list of satistfying statements
        self.service = None   # Remote database server for this predicate?
        self.builtIn = False
        return

    def clone(self):
        """Take a copy when for iterating on a query"""
        x = QueryItem(self.query, self.quad)
        x.state = self.state
        x.short = self.short
        x.neededToRun = []
        x.searchPattern = self.searchPattern[:]
        for p in ALL4:   # Deep copy!  Prevent crosstalk
            x.neededToRun.append(self.neededToRun[p].copy())  
        x.myIndex = self.myIndex
        try:
            x.interpretBuiltins = self.interpretBuiltins
        except AttributeError:
            pass
        return x



    def setup(self, allvars, unmatched, interpretBuiltins=[], mode=""):        
        """Check how many variables in this term,
        and how long it would take to search

        Returns, true normally or false if there is no way this query will work.
        Only called on virgin query item.
        The mode is a set of character flags about how we think."""
        con, pred, subj, obj = self.quad
        self.interpretBuiltins = interpretBuiltins
        self.service = None

        if diag.chatty_flag > 800: progress("setup:" + `allvars`)
        if "r" in mode:
            schema = None
            if "s" in mode:
                schema = pred.dereference(mode, self.query.workingContext)
                if schema != None:
                    if "a" in mode:
                        if diag.chatty_flag > 95:
                            progress("Axiom processing for %s" % (pred))
                        ns = pred.resource
                        rules = schema.any(subj=ns, pred=self.store.docRules)
                        rulefile = rulefile.dereference("m", self.query.workingContext)
                    self.service = schema.any(pred=self.store.definitiveService, subj=pred)
            if self.service == None and self.query.meta != None:
                self.service = self.query.meta.any(pred=self.store.definitiveService, subj=pred)
                if self.service == None:
                    uri = pred.uriref()
                    if uri[:4] == "mysql:":
                        j = uri.rfind("/")
                        if j>0: self.service = meta.newSymbol(uri[:j])
            if diag.chatty_flag > 90 and self.service:
                progress("We have a Remote service %s for %s." %(self.service, pred))
            if not self.service:
                authDoc = None
                if schema != None:
                    authDoc = schema.any(pred=self.store.definitiveDocument, subj=pred)
                if authDoc == None and self.query.meta != None:
                    authDoc = self.query.meta.any(pred=self.store.definitiveDocument, subj=pred)
                if authDoc != None:
                    if diag.chatty_flag > 90:
                        progress("We have a definitive document %s for %s." %(authDoc, pred))
                    authFormula = authDoc.dereference(mode, self.query.workingContext)
                    if authFormula != None:
                        self.quad = (authFormula, pred, subj, obj)
                        con = authFormula

        self.neededToRun = [ Set(), Set(), Set(), Set() ]  # for each part of speech
        self.searchPattern = [con, pred, subj, obj]  # What do we search for?
        hasUnboundCoumpundTerm = 0
        for p in PRED, SUBJ, OBJ :
            x = self.quad[p]
            if x in allvars:   # Variable
                self.neededToRun[p] = Set([x])
                self.searchPattern[p] = None   # can bind this
            elif isinstance(x, Formula) or isinstance(x, List): # expr  @@ Set  @@@@@@@@@@ Check and CompundTerm>???
                ur = x.occurringIn(allvars)
                self.neededToRun[p] = ur
                if ur != Set() or isinstance(x, Formula) or (isinstance(x, List) and hasFormula(x)):
                    hasUnboundCoumpundTerm = 1     # Can't search directly
                    self.searchPattern[p] = None   # can bind this if we recurse
                    
            if diag.chatty_flag > 98: progress("        %s needs to run: %s"%(`x`, `self.neededToRun[p]`))
                
        self.updateMyIndex(con)
        if isinstance(pred, RDFBuiltIn) or (
            interpretBuiltins and isinstance(pred, BuiltIn)):
            self.builtIn = True
        if isinstance(pred, RDFBuiltIn) or (
            interpretBuiltins and isinstance(pred, LightBuiltIn)):
            if self.canRun(): self.state = S_LIGHT_UNS_READY  # Can't do it here
            else: self.state = S_LIGHT_EARLY # Light built-in, can't run yet, not searched
        elif self.short == 0:  # Skip search if no possibilities!
            self.searchDone()
        elif hasUnboundCoumpundTerm:
            self.state = S_NEED_DEEP   # Put off till later than non-deep ones
        else:
            self.state = S_NOT_LIGHT   # Not a light built in, not searched.
        if diag.chatty_flag > 80: progress("setup:" + `self`)
        if self.state == S_DONE: return False
        return True

    def doIncludes(item, queue, existentials, variables, bindings):
        """Implement log:includes by adding all the statements on the LHS
        to the query items.  The plan is that this should"""
        con, pred, subj, obj = item.quad
        state = item.state
        
        nbs = []  # Failure
        if (isinstance(subj, Formula)
            and isinstance(obj, Formula)):
            oldsubj = subj
            subj = subj.renameVars()
            more_unmatched = buildPattern(subj, obj)
            more_variables = obj.variables().copy()
            _substitute({obj: subj}, more_unmatched)
            _substitute(bindings, more_unmatched)
            existentials = existentials | more_variables
            allvars = variables | existentials
            for quad in more_unmatched:
                newItem = QueryItem(item.query, quad)
                queue.append(newItem)
                if not newItem.setup(allvars, interpretBuiltins = 0,
                        unmatched=more_unmatched, mode=item.query.mode):
                    return []
            if diag.chatty_flag > 40:
                    progress("log:Includes: Adding %i new terms and %s as new existentials."%
                              (len(more_unmatched),
                               seqToString(more_variables)))
            rea = BecauseBuiltInWill(subj, con, oldsubj, pred, obj)
##          nbs = [({oldsubj: subj}, rea)]
            nbs = [(Env(), rea)]
        else:
#            if isinstance(subj, Formula): subj = subj.n3String()
#            if isinstance(obj, Formula): obj = obj.n3String()
            #raise RuntimeError("Cannot do {%s} log:includes {%s} " % (subj, obj))
            progress("""Warning: Type error ignored on builtin:
                log:includes only on formulae """+`item`)
                 #@@ was RuntimeError exception
            item.state = S_DONE
        return nbs


    def doSupports(item, queue, existentials, variables, bindings):
        """Real implementation of log:supports. Have fun.

        """
        con, pred, subj, obj = item.quad
        state = item.state
        store = con.store
        #statementObject = iter(con.statementsMatching(subj=subj, pred=pred, obj=obj)).next()

        nbs = []  # Failure
        if (isinstance(subj, Formula)
            and isinstance(obj, Formula)):
            assert subj.canonical != None
            F = store.any((store._experience, store.cufi, subj, None))  # Cached value?
            if F != None:
                if diag.chatty_flag > 10: progress("Bultin: " + `subj`+ " cached log:conclusion " + `F`)
            else:
                oldSubj = subj
                newSubj = subj.renameVars()

                F = subj.newFormula()
                newTopLevelFormula(F)
                if diag.tracking:
                    reason = Premise("Assumption of builtin", item)
                    #reason = BecauseMerge(F, subj)
    #           F.collector = reason
    #           proof.append(reason)
                else: reason = None
                if diag.chatty_flag > 10: progress("Bultin: " + `subj`+ " log:conclusion " + `F`)
                F.loadFormulaWithSubstitution(subj, why=reason, cannon=True) # leave open
                think(F)
                F4 = F.close()
                if F4 is not F:
                    raise RuntimeError
                    ### oh no! we've hit something old!
                    if F is subj:
                        ### absolute worst --- cannot be allowed!
                        F.add(F.newBlankNode(), F.newBlankNode(), F.newBlankNode())
                        F4 = F.close()
                F = F4
                assert subj.canonical != None
                
                store.storeQuad((store._experience, store.cufi, oldSubj, F),
                        why=BecauseOfExperience("conclusion"))  # Cache for later

            more_unmatched = buildPattern(F, obj)
            more_variables = obj.variables().copy()
            _substitute({obj: F}, more_unmatched)
            _substitute(bindings, more_unmatched)
            existentials = existentials | more_variables
            allvars = variables | existentials
            for quad in more_unmatched:
                newItem = QueryItem(item.query, quad)
                queue.append(newItem)
                if not newItem.setup(allvars, interpretBuiltins = 0,
                        unmatched=more_unmatched, mode=item.query.mode):
                    return []
            if diag.chatty_flag > 40:
                    progress("log:Includes: Adding %i new terms and %s as new existentials."%
                              (len(more_unmatched),
                               seqToString(more_variables)))
            rea = BecauseSupportsWill(con, subj, F, pred, obj)
##          nbs = [({oldsubj: subj}, rea)]
            nbs = [(Env(), rea)]
        else:
            if isinstance(subj, Formula): subj = subj.n3String()
            if isinstance(obj, Formula): obj = obj.n3String()
            #raise RuntimeError("Cannot do {%s} log:includes {%s} " % (subj, obj))
            progress("""Warning: Type error ignored on builtin:
                log:include only on formulae """+`item`)
                 #@@ was RuntimeError exception
            item.state = S_DONE
        return nbs



    def tryBuiltin(self, queue, bindings, evidence):                    
        """Check for  built-in functions to see whether it will resolve.
        Return codes:  0 - give up; 
                [] - success, no new bindings, (action has been called)
                [...] list of binding lists, each a pair of bindings and reason."""
        con, pred, subj, obj = self.quad
        proof = []  # place for built-in to hang a justification
        rea = None  # Reason for believing this item is true
        if "q" in self.query.mode:
            caughtErrors = (TypeError, ValueError, AttributeError, AssertionError, ArgumentNotLiteral, UnknownType)
        else:
            caughtErrors = ()
        try:
            if self.neededToRun[SUBJ] == Set():
                if self.neededToRun[OBJ] == Set():   # bound expression - we can evaluate it
                    try:
#                        if pred.eval(subj, obj,  queue, bindings.copy(), proof, self.query):
                        if pred.eval(subj, obj,  BNone, BNone, proof, BNone):
                            if diag.chatty_flag > 80: progress(
                                "Builtin buinary relation operator succeeds")
                            if diag.tracking:
                                rea = BecauseBuiltIn(con, subj, pred, obj)
                                return [(Env(), rea)]  # Involves extra recursion just to track reason
                            return [(Env(), None)]   # No new bindings but success in logical operator
                        else: return []   # We absoluteley know this won't match with this in it

                    except caughtErrors:
                        progress(
                        "Warning: Built-in %s %s %s failed because:\n   %s: %s"
                         % (`subj`, `pred`, `obj`, sys.exc_info()[0].__name__ , 
                             sys.exc_info()[1].__str__()  ))
                        if "h" in self.query.mode:
                            raise
                        return []
                    except BuiltinFeedError:
                        return []
                else: 
                    if isinstance(pred, Function):
                        if diag.chatty_flag > 97:
                            progress("Builtin function call %s(%s)"%(pred, subj))
                        try:
#                            result = pred.evalObj(subj, queue, bindings.copy(), proof, self.query)
                            result = pred.evalObj(subj, BNone, BNone, proof, BNone)
                        except caughtErrors:
                            errVal = (
                            "Warning: Built-in %s!%s failed because:\n   %s: %s"
                             % (`pred`, `subj`, sys.exc_info()[0].__name__ , 
                                 sys.exc_info()[1].__str__()  ))
                            progress(errVal)
                            if "h" in self.query.mode:
                                raise
                            if isinstance(pred, MultipleFunction):
                                result = [ErrorFlag(errVal)]
                            else:
                                result = ErrorFlag(errVal)
                        except BuiltinFeedError:
                            return []
                        if result != None:
                            self.state = S_DONE
                            rea=None
                            if isinstance(result, Formula):
                                if self.quad[OBJ] in self.query.variables:
                                    result.reopen()
                                    result = result.canonicalize(cannon=True)
                                    assert result.canonical is result
                            if diag.tracking:                                
                                if isinstance(result, Formula):
                                    result2 = result.renameVars()
                                    assert result.canonical is result, result.debugString()
                                else:
                                    result2 = result
                            if isinstance(pred, MultipleFunction):
                                return [(Env({obj:(x, None)}),
                                         diag.tracking and BecauseBuiltIn(con, subj, pred, x)
                                         ) for x in result]
                            else:
                                return [(nb1, diag.tracking and BecauseBuiltIn(con, subj, pred, result))
                                        for nb1, env3 in obj.unify(result, Env(), Env(), self.neededToRun[OBJ])]
##                                return [(Env({obj: (result, None)}),
##                                         diag.tracking and BecauseBuiltIn(con, subj, pred, result))]
                        else:
                            return []
            else:
                if (self.neededToRun[OBJ] == Set()):
                    if isinstance(pred, ReverseFunction):
                        if diag.chatty_flag > 97: progress("Builtin Rev function call %s(%s)"%(pred, obj))
                        try:
#                            result = pred.evalSubj(obj, queue, bindings.copy(), proof, self.query)
                            result = pred.evalSubj(obj, BNone, BNone, proof, BNone)
                        except caughtErrors:
                            errVal = (
                            "Warning: Built-in %s^%s failed because:\n   %s: %s"
                             % (`pred`, `obj`, sys.exc_info()[0].__name__ , 
                                 sys.exc_info()[1].__str__()  ))
                            progress(errVal)
                            if "h" in self.query.mode:
                                raise
                            if isinstance(pred, MultipleReverseFunction):
                                result = [ErrorFlag(errVal)]
                            else:
                                result = ErrorFlag(errVal)

                        except BuiltinFeedError:
                            return []
                        if result != None:
                            self.state = S_DONE
                            if isinstance(pred, MultipleReverseFunction):
                                return [(Env({subj:(x,None)}),
                                         diag.tracking and \
                                         BecauseBuiltIn(con, x, pred, obj)) \
                                        for x in result]
                            else:
                                return [(nb1, diag.tracking and BecauseBuiltIn(con, subj, pred, result))
                                        for nb1, env3 in subj.unify(result, Env(), Env(), self.neededToRun[SUBJ])]
##                                return [(Env({subj: (result,None)}),
##                                         diag.tracking and \
##                                         BecauseBuiltIn(con, result, pred, obj)
##                                         )]
                        else:
                            return []
                else:
                    if isinstance(pred, FiniteProperty):
                        result = pred.ennumerate()
                        if result != 0:
                            self.state = S_DONE
                            return result  # Generates its own list of (list of bindings, reason)s
                        else:
                            return []
            if diag.chatty_flag > 30:
                progress("Builtin could not give result"+`self`)
            return []   # no solution
            # @@@ remove dependency on 'heavy' above and remove heavy as param
        except (IOError, SyntaxError):
            raise BuiltInFailed(sys.exc_info(), self, pred ),None
        
    def tryDeepSearch(self, queue, oldBindings=Env()):
        """Search the store, unifying nested compound structures
        
        Returns lists of list of bindings, attempting if necessary to unify
        any nested compound terms. Added 20030810, not sure whether it is worth the
        execution time in practice. It could be left to a special magic built-in like "matches"
        or something if it is only occasionnaly used.
        
        Used in state S_NEED_DEEP
        """
        nbs = [] # Assume failure
        if self.short == INFINITY:
            if diag.chatty_flag > 36:
                progress( "Can't deep search for %s" % `self`)
        else:
            if diag.chatty_flag > 36:
                progress( "Searching (S=%i) %i for %s" %(self.state, self.short, `self`))
            try:
                for s in self.myIndex:
                    pass
            except:
                print self.myIndex, self
                raise
            for s in self.myIndex :  # for everything matching what we know,
                if self.query.justReturn and s in queue.statements:
                    continue
                env_queue = [(oldBindings, Env())]
                ### Why not just unify here?
                if diag.chatty_flag > 106: progress("...checking %r" % s)
                for p in PRED, SUBJ, OBJ:
                    if self.searchPattern[p] == None: # Need to check
                        eq = env_queue
                        env_queue = []
                        for nb, env2 in eq:
                            x = self.quad[p]
                            if self.neededToRun[p] == Set([x]):   # a term with no variables
                                if nb.canBind(x, s.quad[p]):
                                    nb = nb.bind(x, (s.quad[p], env2))
                                    env_queue.append((nb, env2))
                            else:  # Deep case   
                                if diag.chatty_flag > 70:
                                    progress( "Deep: Unify %s with %s vars=%s; ee=%s" %
                                    (x, s.quad[p], `self.query.variables`[4:-1],
                                    `self.query._existentialVariables`[4:-1]))
                                for nb1, env3 in x.unify(s.quad[p], nb, env2, self.neededToRun[p]):
                                    env_queue.append((nb1, env3))
##                                nbs1 = x.unify(s.quad[p], self.neededToRun[p] & self.query.variables,
##                                    self.neededToRun[p] & self.query._existentialVariables, {})  # Bindings have all been bound
                                
                for nb, _ in env_queue: 
                    nbs.append((nb, s))  # Add the new bindings into the set

        self.searchDone()  # State transitions
        return nbs   # End try deep search

    def searchDone(self):
        """Search has been done: figure out next state."""
        con, pred, subj, obj = self.quad
        if self.state == S_LIGHT_EARLY:   # Light, can't run yet.
            self.state = S_LIGHT_WAIT    # Search done, can't run
        elif self.state == S_LIGHT_UNS_READY: # Still have to run this light one
            return
        elif self.service:
            self.state = S_REMOTE    #  Search done, need to synchronize with other items
        elif not isinstance(pred, HeavyBuiltIn) or not self.interpretBuiltins:
            self.state = S_DONE  # Done with this one: Do new bindings & stop
        elif self.canRun():
            self.state = S_HEAVY_READY
        else:
            self.state = S_HEAVY_WAIT
        if diag.chatty_flag > 90:
            progress("...searchDone, now ",self)
        return
    
    def canRun(self):
        "Is this built-in ready to run?"

        if (self.neededToRun[SUBJ] == Set()):
            if (self.neededToRun[OBJ] == Set()): return 1
            else:
                pred = self.quad[PRED]
                return (isinstance(pred, Function)
                          or pred is self.store.includes
                          or pred is self.store.supports)  # Can use variables
        else:
            if (self.neededToRun[OBJ] == Set()):
                return isinstance(self.quad[PRED], ReverseFunction)


    def bindNew(self, newBindings):
        """Take into account new bindings from query processing to date

        The search may get easier, and builtins may become ready to run.
        Lists may either be matched against store by searching,
        and/or may turn out to be bound and therefore ready to run.
        
        Return:
            0           No way can this item ever complete.
            None        Binding done, see item.state 
        """
        con, pred, subj, obj = self.quad
        if diag.chatty_flag > 90:
            progress(" binding ", `self` + " with "+ `newBindings`)
        q=[con, pred, subj, obj]
        for p in ALL4:
            changed = 0
            for var, val in newBindings.items():
                if var in self.neededToRun[p]:
                    self.neededToRun[p].remove(var)
                    changed = 1
                if q[p] is var and self.searchPattern[p]==None:
                    self.searchPattern[p] = val # const now
                    changed = 1
                    self.neededToRun[p].clear() # Now it is definitely all bound
            if changed:
                q[p] = q[p].substitution(newBindings.asDict(), why=becauseSubexpression)   # possibly expensive
                if self.searchPattern[p] != None: self.searchPattern[p] = q[p]
                
        self.quad = q[0], q[1], q[2], q[3]  # yuk

        if self.state in [S_NOT_LIGHT, S_LIGHT_EARLY, S_NEED_DEEP, S_LIGHT_UNS_READY]: # Not searched yet
            hasUnboundCoumpundTerm = 0
            for p in PRED, SUBJ, OBJ :
                x = self.quad[p]
                if hasFormula(x): # expr  @@ Set  @@@@@@@@@@ Check and CompundTerm>???
#                    ur = x.freeVariables()
                    ur = x.occurringIn(self.neededToRun[p])
                    self.neededToRun[p] = ur
                    hasUnboundCoumpundTerm = 1     # Can't search directly
                    self.searchPattern[p] = None   # can bind this if we recurse

        
##            for p in PRED, SUBJ, OBJ:
##                x = self.quad[p]
##                if isinstance(x, Formula):
##                    if self.neededToRun[p]!= Set():
##                        self.short = INFINITY  # Forget it
##                        break
            else:
                self.updateMyIndex(con)

            if self.short == 0:
                self.searchDone()
        else:
            self.short = 7700+self.state  # Should not be used
            self.myIndex = None
        if isinstance(self.quad[PRED], BuiltIn):
            if self.canRun():
                if self.state == S_LIGHT_EARLY: self.state = S_LIGHT_UNS_READY
                elif self.state == S_LIGHT_WAIT: self.state = S_LIGHT_GO
                elif self.state == S_HEAVY_WAIT: self.state = S_HEAVY_READY
        if diag.chatty_flag > 90:
            progress("...bound becomes ", `self`)
        if self.state == S_DONE: return []
        return [({}, None)] # continue

    def updateMyIndex(self, formula):
        self.short, self.myIndex = formula.searchable(
                                            self.searchPattern[SUBJ],
                                           self.searchPattern[PRED],
                                           self.searchPattern[OBJ])
        if isinstance(self.quad[SUBJ], Formula) and self.short:
            self.short = self.short * 3 + len(self.quad[SUBJ]) * 100
        if isinstance(self.quad[OBJ], Formula) and self.short:
            self.short = self.short * 3 + len(self.quad[OBJ]) * 100
        for p in SUBJ, OBJ :
            if isinstance(self.quad[p], Formula) and not self.neededToRun[p]:
                newIndex = []
                for triple in self.myIndex:
                    if isinstance(triple[p], Formula) and len(triple[p]) == len(self.quad[p]):
                        newIndex.append(triple)
                self.myIndex = newIndex
        
##        self.myIndex = []
##        for triple in myIndex:
##            for loc in SUBJ, PRED, OBJ:
##                node = triple[loc]
##                if node in formula.variables() and self.searchPattern[loc] is not None:
##                    break
##            else:
##                self.myIndex.append(triple)

    def __repr__(self):
        """Diagnostic string only"""
        s = "%3i) short=%i, %s" % (
                self.state, self.short,
                quadToString(self.quad, self.neededToRun, self.searchPattern))
        if self.service: s += (", servce=%s " % self.service)
        return s


##############
# Compare two cyclic subsystem sto see which should be done first

def compareCyclics(self,other):
    """Note the set indirectly affected is the same for any
    member of a cyclic subsystem"""
    if other[0] in self[0].indirectlyAffects:
        return -1  # Do me earlier
    if other[0] in self[0].indirectlyAffectedBy:
        return 1
    return 0
        


#############  Substitution functions    


def _substitute(bindings, list):
    """Subsitustes IN-LINE into a list of quads"""
    for i in range(len(list)):
        q = list[i]
        list[i] = lookupQuad(bindings, q)
                            
def lookupQuad(bindings, q):
        "Return a subsituted quad"
        context, pred, subj, obj = q
        return (bindings.get(context, context),
                bindings.get(pred, pred),
                bindings.get(subj, subj),
                bindings.get(obj, obj))


def lookupQuadRecursive(bindings, q, why=None):
        context, pred, subj, obj = q
        if diag.chatty_flag > 99: progress("\tlookupQuadRecursive:", q)
        return (
            context.substitution(bindings),
            pred.substitution(bindings),
            subj.substitution(bindings),
            obj.substitution(bindings) )

#   DIAGNOSTIC STRING OUTPUT
#
def queueToString(queue):
    str = ""
    for item in queue:
        str = str  +  `item` + "\n"
    return str


def setToString(set):
    str = ""
    for q in set:
        str = str+ "        " + quadToString(q) + "\n"
    return str

def quadToString(q, neededToRun=[[],[],[],[]], pattern=[1,1,1,1]):
    qm=[" "," "," "," "]
    for p in ALL4:
        n = neededToRun[p]
        if n == []: qm[p]=""
        else: qm[p] = "(" + `n`[5:-2] + ")"  # Set([...]) ->  (...)
        if pattern[p]==None: qm[p]=qm[p]+"?"
    return "%s%s ::  %8s%s %8s%s %8s%s." %(`q[CONTEXT]`, qm[CONTEXT],
                                            `q[SUBJ]`,qm[SUBJ],
                                            `q[PRED]`,qm[PRED],
                                            `q[OBJ]`,qm[OBJ])

def seqToString(set):
#    return `set`
    set = list(set)
    str = ""
    for x in set[:-1]:
        str = str + `x` + ","
    for x in set[-1:]:
        str = str+ `x`
    return str

def bindingsToString(bindings):
#    return `bindings`

    str = ""
    for x, y in bindings.items():
        str = str + (" %s->%s " % ( `x`, `y`))
    return str

class BecauseBuiltInWill(object):
    def __init__(self, *args):
        self.args = args

class BecauseSupportsWill(object):
    def __init__(self, *args):
        self.args = args

class BuiltInFailed(Exception):
    def __init__(self, info, item, pred):
        progress("BuiltIn %s FAILED" % pred, `info`)
        self._item = item
        self._info = info
        self._pred = pred
        
    def __str__(self):
        reason = indentString(self._info[1].__str__())
#        return "reason=" + reason
        return ("Error during built-in operation\n%s\nbecause:\n%s" % (
            `self._item`,
#            `self._info`))
            `reason`))

def hasFormula(l):
    if not isinstance(l, (List, Formula)):
        return False
    if isinstance(l, Formula):
        return True
    for x in l:
        if hasFormula(x):
            return True
    return False

from term import AnonymousNode, CompoundTerm

def smarterSubstitution(f, bindings, source, why=None, exception=[]):
    bindings = bindings.asDict()
    if f in exception:
        return f
    if isinstance(f, Formula):
        f2 = f.newFormula()
        newBindings, _ = f2.loadFormulaWithSubstitution(f, bindings, why=Because("I said so #2", why))
        if f is not source:
            newExistentials = f2.occurringIn(source.existentials().intersection(Set(bindings.values())))
            for n in newExistentials:
                f2.declareExistential(n)
##            for k in bindings.values():
##                if k not in newExistentials and isinstance(k, AnonymousNode) and not isinstance(k,CompoundTerm) and f2.occurringIn(Set([k])) and len(f2) < 20:
##                    raise RuntimeError('How did I get here? newBindings=%s, bindings=%s, k=%s, f=%s, source=%s' % (newBindings, bindings, k, f2.debugString(), source.debugString()))
        rr = f2.close()
        return rr
    rr = f.substitution(bindings, why=Because("I said so #3", why))
    return rr

# ends