summaryrefslogtreecommitdiff
path: root/src/iflow.sml
blob: 8bde7ea33f775a50772d613a0d5f75812dea4a62 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
(* Copyright (c) 2010, 2013, Adam Chlipala
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * - The names of contributors may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *)

structure Iflow :> IFLOW = struct

open Mono
open Sql

structure IS = IntBinarySet
structure IM = IntBinaryMap

structure SK = struct
type ord_key = string
val compare = String.compare
end

structure SS = BinarySetFn(SK)
structure SM = BinaryMapFn(SK)

val writers = ["htmlifyInt_w",
               "htmlifyFloat_w",
               "htmlifyString_w",
               "htmlifyBool_w",
               "htmlifyTime_w",
               "attrifyInt_w",
               "attrifyFloat_w",
               "attrifyString_w",
               "attrifyChar_w",
               "urlifyInt_w",
               "urlifyFloat_w",
               "urlifyString_w",
               "urlifyBool_w",
               "set_cookie"]

val writers = SS.addList (SS.empty, writers)

local
    open Print
    val string = PD.string
in

fun p_func f =
    string (case f of
                DtCon0 s => s
              | DtCon1 s => s
              | UnCon s => "un" ^ s
              | Other s => s)

fun p_exp e =
    case e of
        Const p => Prim.p_t p
      | Var n => string ("x" ^ Int.toString n)
      | Lvar n => string ("X" ^ Int.toString n)
      | Func (f, es) => box [p_func f,
                             string "(",
                             p_list p_exp es,
                             string ")"]
      | Recd xes => box [string "{",
                         p_list (fn (x, e) => box [string x,
                                                   space,
                                                   string "=",
                                                   space,
                                                   p_exp e]) xes,
                         string "}"]
      | Proj (e, x) => box [p_exp e,
                            string ("." ^ x)]

fun p_bop s es =
    case es of
        [e1, e2] => box [p_exp e1,
                         space,
                         string s,
                         space,
                         p_exp e2]
      | _ => raise Fail "Iflow.p_bop"

fun p_reln r es =
    case r of
        Known =>
        (case es of
             [e] => box [string "known(",
                         p_exp e,
                         string ")"]
           | _ => raise Fail "Iflow.p_reln: Known")
      | Sql s => box [string (s ^ "("),
                      p_list p_exp es,
                      string ")"]
      | PCon0 s => box [string (s ^ "("),
                        p_list p_exp es,
                        string ")"]
      | PCon1 s => box [string (s ^ "("),
                        p_list p_exp es,
                        string ")"]
      | Cmp Eq => p_bop "=" es
      | Cmp Ne => p_bop "<>" es
      | Cmp Lt => p_bop "<" es
      | Cmp Le => p_bop "<=" es
      | Cmp Gt => p_bop ">" es
      | Cmp Ge => p_bop ">=" es

fun p_prop p =
    case p of
        True => string "True"
      | False => string "False"
      | Unknown => string "??"
      | Lop (And, p1, p2) => box [string "(",
                                  p_prop p1,
                                  string ")",
                                  space,
                                  string "&&",
                                  space,
                                  string "(",
                                  p_prop p2,
                                  string ")"]
      | Lop (Or, p1, p2) => box [string "(",
                                 p_prop p1,
                                 string ")",
                                 space,
                                 string "||",
                                 space,
                                 string "(",
                                 p_prop p2,
                                 string ")"]
      | Reln (r, es) => p_reln r es
      | Cond (e, p) => box [string "(",
                            p_exp e,
                            space,
                            string "==",
                            space,
                            p_prop p,
                            string ")"]

end

fun isKnown e =
    case e of
        Const _ => true
      | Func (_, es) => List.all isKnown es
      | Recd xes => List.all (isKnown o #2) xes
      | Proj (e, _) => isKnown e
      | _ => false

fun simplify unif =
    let
        fun simplify e =
            case e of
                Const _ => e
              | Var _ => e
              | Lvar n =>
                (case IM.find (unif, n) of
                     NONE => e
                   | SOME e => simplify e)
              | Func (f, es) => Func (f, map simplify es)
              | Recd xes => Recd (map (fn (x, e) => (x, simplify e)) xes)
              | Proj (e, s) => Proj (simplify e, s)
    in
        simplify
    end

datatype atom =
         AReln of reln * exp list
       | ACond of exp * prop

fun p_atom a =
    p_prop (case a of
                AReln x => Reln x
              | ACond x => Cond x)

(* Congruence closure *)
structure Cc :> sig
    type database

    exception Contradiction

    val database : unit -> database
    val clear : database -> unit

    val assert : database * atom -> unit
    val check : database * atom -> bool

    val p_database : database Print.printer

    val builtFrom : database * {Base : exp list, Derived : exp} -> bool

    val p_repOf : database -> exp Print.printer
end = struct

local
    val count = ref 0
in
fun nodeId () =
    let
        val n = !count
    in
        count := n + 1;
        n
    end
end

exception Contradiction
exception Undetermined

structure CM = BinaryMapFn(struct
                           type ord_key = Prim.t
                           val compare = Prim.compare
                           end)

datatype node = Node of {Id : int,
                         Rep : node ref option ref,
                         Cons : node ref SM.map ref,
                         Variety : variety,
                         Known : bool ref,
                         Ge : Int64.int option ref}

     and variety =
         Dt0 of string
       | Dt1 of string * node ref
       | Prim of Prim.t
       | Recrd of node ref SM.map ref * bool
       | Nothing

type representative = node ref

type database = {Vars : representative IM.map ref,
                 Consts : representative CM.map ref,
                 Con0s : representative SM.map ref,
                 Records : (representative SM.map * representative) list ref,
                 Funcs : ((string * representative list) * representative) list ref}

fun database () = {Vars = ref IM.empty,
                   Consts = ref CM.empty,
                   Con0s = ref SM.empty,
                   Records = ref [],
                   Funcs = ref []}

fun clear (t : database) = (#Vars t := IM.empty;
                            #Consts t := CM.empty;
                            #Con0s t := SM.empty;
                            #Records t := [];
                            #Funcs t := [])

fun unNode n =
    case !n of
        Node r => r

open Print
val string = PD.string
val newline = PD.newline

fun p_rep n =
    case !(#Rep (unNode n)) of
        SOME n => p_rep n
      | NONE =>
        box [string (Int.toString (#Id (unNode n)) ^ ":"),
             space,
             case #Variety (unNode n) of
                 Nothing => string "?"
               | Dt0 s => string ("Dt0(" ^ s ^ ")")
               | Dt1 (s, n) => box[string ("Dt1(" ^ s ^ ","),
                                   space,
                                   p_rep n,
                                   string ")"]
               | Prim p => Prim.p_t p
               | Recrd (ref m, b) => box [string "{",
                                          p_list (fn (x, n) => box [string x,
                                                                    space,
                                                                    string "=",
                                                                    space,
                                                                    p_rep n]) (SM.listItemsi m),
                                          string "}",
                                          if b then
                                              box [space,
                                                   string "(complete)"]
                                          else
                                              box []],
             if !(#Known (unNode n)) then
                 string " (known)"
             else
                 box [],
             case !(#Ge (unNode n)) of
                 NONE => box []
               | SOME n => string (" (>= " ^ Int64.toString n ^ ")")]

fun p_database (db : database) =
    box [string "Vars:",
         newline,
         p_list_sep newline (fn (i, n) => box [string ("x" ^ Int.toString i),
                                               space,
                                               string "=",
                                               space,
                                               p_rep n]) (IM.listItemsi (!(#Vars db)))]

fun repOf (n : representative) : representative =
    case !(#Rep (unNode n)) of
        NONE => n
      | SOME r =>
        let
            val r = repOf r
        in
            #Rep (unNode n) := SOME r;
            r
        end

fun markKnown r =
    let
        val r = repOf r
    in
        (*Print.preface ("markKnown", p_rep r);*)
        if !(#Known (unNode r)) then
            ()(*TextIO.print "Already known\n"*)
        else
            (#Known (unNode r) := true;
             SM.app markKnown (!(#Cons (unNode r)));
             case #Variety (unNode r) of
                 Dt1 (_, r) => markKnown r
               | Recrd (xes, _) => SM.app markKnown (!xes)
               | _ => ())
    end

fun representative (db : database, e) =
    let
        fun rep e =
            case e of
                Const p => (case CM.find (!(#Consts db), p) of
                                SOME r => repOf r
                              | NONE =>
                                let
                                    val r = ref (Node {Id = nodeId (),
                                                       Rep = ref NONE,
                                                       Cons = ref SM.empty,
                                                       Variety = Prim p,
                                                       Known = ref true,
                                                       Ge = ref (case p of
                                                                     Prim.Int n => SOME n
                                                                   | _ => NONE)})
                                in
                                    #Consts db := CM.insert (!(#Consts db), p, r);
                                    r
                                end)
              | Var n => (case IM.find (!(#Vars db), n) of
                              SOME r => repOf r
                            | NONE =>
                              let
                                  val r = ref (Node {Id = nodeId (),
                                                     Rep = ref NONE,
                                                     Cons = ref SM.empty,
                                                     Variety = Nothing,
                                                     Known = ref false,
                                                     Ge = ref NONE})
                              in
                                  #Vars db := IM.insert (!(#Vars db), n, r);
                                  r
                              end)
              | Lvar _ => raise Undetermined
              | Func (DtCon0 f, []) => (case SM.find (!(#Con0s db), f) of
                                            SOME r => repOf r
                                          | NONE =>
                                            let
                                                val r = ref (Node {Id = nodeId (),
                                                                   Rep = ref NONE,
                                                                   Cons = ref SM.empty,
                                                                   Variety = Dt0 f,
                                                                   Known = ref true,
                                                                   Ge = ref NONE})
                                            in
                                                #Con0s db := SM.insert (!(#Con0s db), f, r);
                                                r
                                            end)
              | Func (DtCon0 _, _) => raise Fail "Iflow.rep: DtCon0"
              | Func (DtCon1 f, [e]) =>
                let
                    val r = rep e
                in
                    case SM.find (!(#Cons (unNode r)), f) of
                        SOME r => repOf r
                      | NONE =>
                        let
                            val r' = ref (Node {Id = nodeId (),
                                                Rep = ref NONE,
                                                Cons = ref SM.empty,
                                                Variety = Dt1 (f, r),
                                                Known = ref (!(#Known (unNode r))),
                                                Ge = ref NONE})
                        in
                            #Cons (unNode r) := SM.insert (!(#Cons (unNode r)), f, r');
                            r'
                        end
                end
              | Func (DtCon1 _, _) => raise Fail "Iflow.rep: DtCon1"
              | Func (UnCon f, [e]) =>
                let
                    val r = rep e
                in
                    case #Variety (unNode r) of
                        Dt1 (f', n) => if f' = f then
                                           repOf n
                                       else
                                           raise Contradiction
                      | Nothing =>
                        let
                            val cons = ref SM.empty
                            val r' = ref (Node {Id = nodeId (),
                                                Rep = ref NONE,
                                                Cons = cons,
                                                Variety = Nothing,
                                                Known = ref (!(#Known (unNode r))),
                                                Ge = ref NONE})

                            val r'' = ref (Node {Id = nodeId (),
                                                 Rep = ref NONE,
                                                 Cons = #Cons (unNode r),
                                                 Variety = Dt1 (f, r'),
                                                 Known = #Known (unNode r),
                                                 Ge = ref NONE})
                        in
                            cons := SM.insert (!cons, f, r'');
                            #Rep (unNode r) := SOME r'';
                            r'
                        end
                      | _ => raise Contradiction
                end
              | Func (UnCon _, _) => raise Fail "Iflow.rep: UnCon"
              | Func (Other f, es) =>
                let
                    val rs = map rep es
                in
                    case List.find (fn (x : string * representative list, _) => x = (f, rs)) (!(#Funcs db)) of
                        NONE =>
                        let
                            val r = ref (Node {Id = nodeId (),
                                               Rep = ref NONE,
                                               Cons = ref SM.empty,
                                               Variety = Nothing,
                                               Known = ref (f = "allow"),
                                               Ge = ref NONE})
                        in
                            #Funcs db := ((f, rs), r) :: (!(#Funcs db));
                            r
                        end
                      | SOME (_, r) => repOf r
                end
              | Recd xes =>
                let
                    val xes = map (fn (x, e) => (x, rep e)) xes
                    val len = length xes
                in
                    case List.find (fn (xes', _) =>
                                       SM.numItems xes' = len
                                       andalso List.all (fn (x, n) =>
                                                            case SM.find (xes', x) of
                                                                NONE => false
                                                             | SOME n' => n = repOf n') xes)
                         (!(#Records db)) of
                        SOME (_, r) => repOf r
                      | NONE =>
                        let
                            val xes = foldl SM.insert' SM.empty xes

                            val r' = ref (Node {Id = nodeId (),
                                                Rep = ref NONE,
                                                Cons = ref SM.empty,
                                                Variety = Recrd (ref xes, true),
                                                Known = ref false,
                                                Ge = ref NONE})
                        in
                            #Records db := (xes, r') :: (!(#Records db));
                            r'
                        end
                end
              | Proj (e, f) =>
                let
                    val r = rep e
                in
                    case #Variety (unNode r) of
                        Recrd (xes, _) =>
                        (case SM.find (!xes, f) of
                             SOME r => repOf r
                           | NONE => let
                                  val r = ref (Node {Id = nodeId (),
                                                     Rep = ref NONE,
                                                     Cons = ref SM.empty,
                                                     Variety = Nothing,
                                                     Known = ref (!(#Known (unNode r))),
                                                     Ge = ref NONE})
                              in
                                 xes := SM.insert (!xes, f, r);
                                 r
                              end)
                      | Nothing =>
                        let
                            val r' = ref (Node {Id = nodeId (),
                                                Rep = ref NONE,
                                                Cons = ref SM.empty,
                                                Variety = Nothing,
                                                Known = ref (!(#Known (unNode r))),
                                                Ge = ref NONE})

                            val r'' = ref (Node {Id = nodeId (),
                                                 Rep = ref NONE,
                                                 Cons = #Cons (unNode r),
                                                 Variety = Recrd (ref (SM.insert (SM.empty, f, r')), false),
                                                 Known = #Known (unNode r),
                                                 Ge = ref NONE})
                        in
                            #Rep (unNode r) := SOME r'';
                            r'
                        end
                      | _ => raise Contradiction
                end
    in
        rep e
    end

fun p_repOf db e = p_rep (representative (db, e))

fun assert (db, a) =
    let
        fun markEq (r1, r2) =
            let
                val r1 = repOf r1
                val r2 = repOf r2
            in
                if r1 = r2 then
                    ()
                else case (#Variety (unNode r1), #Variety (unNode r2)) of
                         (Prim p1, Prim p2) => if Prim.equal (p1, p2) then
                                                   ()
                                               else
                                                   raise Contradiction
                       | (Dt0 f1, Dt0 f2) => if f1 = f2 then
                                                 ()
                                             else
                                                 raise Contradiction
                       | (Dt1 (f1, r1), Dt1 (f2, r2)) => if f1 = f2 then
                                                             markEq (r1, r2)
                                                         else
                                                             raise Contradiction
                       | (Recrd (xes1, _), Recrd (xes2, _)) =>
                         let
                             fun unif (xes1, xes2) =
                                 SM.appi (fn (x, r1) =>
                                             case SM.find (!xes2, x) of
                                                 NONE => xes2 := SM.insert (!xes2, x, r1)
                                               | SOME r2 => markEq (r1, r2)) (!xes1)
                         in
                             unif (xes1, xes2);
                             unif (xes2, xes1)
                         end
                       | (Nothing, _) => mergeNodes (r1, r2)
                       | (_, Nothing) => mergeNodes (r2, r1)
                       | _ => raise Contradiction
            end

        and mergeNodes (r1, r2) =
            (#Rep (unNode r1) := SOME r2;
             if !(#Known (unNode r1)) then
                 markKnown r2
             else
                 ();
             if !(#Known (unNode r2)) then
                 markKnown r1
             else
                 ();
             #Cons (unNode r2) := SM.unionWith #1 (!(#Cons (unNode r2)), !(#Cons (unNode r1)));

             case !(#Ge (unNode r1)) of
                 NONE => ()
               | SOME n1 =>
                 case !(#Ge (unNode r2)) of
                     NONE => #Ge (unNode r2) := SOME n1
                   | SOME n2 => #Ge (unNode r2) := SOME (Int64.max (n1, n2));

             compactFuncs ())

        and compactFuncs () =
            let
                fun loop funcs =
                    case funcs of
                        [] => []
                      | (fr as ((f, rs), r)) :: rest =>
                        let
                            val rest = List.filter (fn ((f' : string, rs'), r') =>
                                                       if f' = f
                                                          andalso ListPair.allEq (fn (r1, r2) =>
                                                                                     repOf r1 = repOf r2)
                                                                                 (rs, rs') then
                                                           (markEq (r, r');
                                                            false)
                                                       else
                                                           true) rest
                        in
                            fr :: loop rest
                        end
            in
                #Funcs db := loop (!(#Funcs db))
            end
    in
        case a of
            ACond _ => ()
          | AReln x =>
            case x of
                (Known, [e]) =>
                ((*Print.prefaces "Before" [("e", p_exp e),
                                            ("db", p_database db)];*)
                 markKnown (representative (db, e))(*;
                                                        Print.prefaces "After" [("e", p_exp e),
                                                                                ("db", p_database db)]*))
              | (PCon0 f, [e]) =>
                let
                    val r = representative (db, e)
                in
                    case #Variety (unNode r) of
                        Dt0 f' => if f = f' then
                                      ()
                                  else
                                      raise Contradiction
                      | Nothing =>
                        (case SM.find (!(#Con0s db), f) of
                             SOME r' => markEq (r, r')
                           | NONE =>
                             let
                                 val r' = ref (Node {Id = nodeId (),
                                                     Rep = ref NONE,
                                                     Cons = ref SM.empty,
                                                     Variety = Dt0 f,
                                                     Known = ref false,
                                                     Ge = ref NONE})
                             in
                                 #Rep (unNode r) := SOME r';
                                 #Con0s db := SM.insert (!(#Con0s db), f, r')
                             end)
                      | _ => raise Contradiction
                end
              | (PCon1 f, [e]) =>
                let
                    val r = representative (db, e)
                in
                    case #Variety (unNode r) of
                        Dt1 (f', e') => if f = f' then
                                            ()
                                        else
                                            raise Contradiction
                      | Nothing =>
                        let
                            val cons = ref SM.empty

                            val r'' = ref (Node {Id = nodeId (),
                                                 Rep = ref NONE,
                                                 Cons = cons,
                                                 Variety = Nothing,
                                                 Known = ref (!(#Known (unNode r))),
                                                 Ge = ref NONE})

                            val r' = ref (Node {Id = nodeId (),
                                                Rep = ref NONE,
                                                Cons = ref SM.empty,
                                                Variety = Dt1 (f, r''),
                                                Known = #Known (unNode r),
                                                Ge = ref NONE})
                        in
                            cons := SM.insert (!cons, f, r');
                            #Rep (unNode r) := SOME r'
                        end
                      | _ => raise Contradiction
                end
              | (Cmp Eq, [e1, e2]) =>
                markEq (representative (db, e1), representative (db, e2))
              | (Cmp Ge, [e1, e2]) =>
                let
                    val r1 = representative (db, e1)
                    val r2 = representative (db, e2)
                in
                    case !(#Ge (unNode (repOf r2))) of
                        NONE => ()
                      | SOME n2 =>
                        case !(#Ge (unNode (repOf r1))) of
                            NONE => #Ge (unNode (repOf r1)) := SOME n2
                          | SOME n1 => #Ge (unNode (repOf r1)) := SOME (Int64.max (n1, n2))
                end
              | _ => ()
    end handle Undetermined => ()

fun check (db, a) =
    (case a of
         ACond _ => false
       | AReln x =>
         case x of
             (Known, [e]) =>
             let
                 fun isKnown r =
                     let
                         val r = repOf r
                     in
                         !(#Known (unNode r))
                         orelse case #Variety (unNode r) of
                                    Dt1 (_, r) => isKnown r
                                  | Recrd (xes, true) => List.all isKnown (SM.listItems (!xes))
                                  | _ => false
                     end

                 val r = representative (db, e)
             in
                 isKnown r
             end
           | (PCon0 f, [e]) =>
             (case #Variety (unNode (representative (db, e))) of
                  Dt0 f' => f' = f
                | _ => false)
           | (PCon1 f, [e]) =>
             (case #Variety (unNode (representative (db, e))) of
                  Dt1 (f', _) => f' = f
                | _ => false)
           | (Cmp Eq, [e1, e2]) =>
             let
                 val r1 = representative (db, e1)
                 val r2 = representative (db, e2)
             in
                 repOf r1 = repOf r2
             end
           | (Cmp Ge, [e1, e2]) =>
             let
                 val r1 = representative (db, e1)
                 val r2 = representative (db, e2)
             in
                 case (!(#Ge (unNode (repOf r1))), #Variety (unNode (repOf r2))) of
                     (SOME n1, Prim (Prim.Int n2)) => Int64.>= (n1, n2)
                   | _ => false
             end
           | _ => false)
    handle Undetermined => false

fun builtFrom (db, {Base = bs, Derived = d}) =
    let
        val bs = map (fn b => representative (db, b)) bs

        fun loop d =
            let
                val d = repOf d
            in
                !(#Known (unNode d))
                orelse List.exists (fn b => repOf b = d) bs
                orelse (case #Variety (unNode d) of
                            Dt0 _ => true
                          | Dt1 (_, d) => loop d
                          | Prim _ => true
                          | Recrd (xes, _) => List.all loop (SM.listItems (!xes))
                          | Nothing => false)
                orelse List.exists (fn r => List.exists (fn b => repOf b = repOf r) bs)
                                   (SM.listItems (!(#Cons (unNode d))))
            end

        fun decomp e =
            case e of
                Func (Other _, es) => List.all decomp es
              | _ => loop (representative (db, e))
    in
        decomp d
    end handle Undetermined => false

end

val tabs = ref (SM.empty : (string list * string list list) SM.map)

fun patCon pc =
    case pc of
        PConVar n => "C" ^ Int.toString n
      | PConFfi {mod = m, datatyp = d, con = c, ...} => m ^ "." ^ d ^ "." ^ c

type check = exp * ErrorMsg.span

structure St :> sig
    val reset : unit -> unit

    type stashed
    val stash : unit -> stashed
    val reinstate : stashed -> unit

    type stashedPath
    val stashPath : unit -> stashedPath
    val reinstatePath : stashedPath -> unit

    val nextVar : unit -> int

    val assert : atom list -> unit

    val addPath : check -> unit

    val allowSend : atom list * exp list -> unit
    val send : check -> unit

    val allowInsert : atom list -> unit
    val insert : ErrorMsg.span -> unit

    val allowDelete : atom list -> unit
    val delete : ErrorMsg.span -> unit

    val allowUpdate : atom list -> unit
    val update : ErrorMsg.span -> unit

    val havocReln : reln -> unit
    val havocCookie : string -> unit

    val check : atom -> bool

    val debug : unit -> unit
end = struct

val hnames = ref 1

type hyps = int * atom list * bool ref

val db = Cc.database ()
val path = ref ([] : ((int * atom list) * check) option ref list)
val hyps = ref (0, [] : atom list, ref false)
val nvar = ref 0

fun setHyps (n', hs) =
    let
        val (n, _, _) = !hyps
    in
        if n' = n then
            ()
        else
            (hyps := (n', hs, ref false);
             Cc.clear db;
             app (fn a => Cc.assert (db, a)) hs)
    end

fun useKeys () =
    let
        val changed = ref false

        fun findKeys (hyps, acc) =
            case hyps of
                [] => rev acc
              | (a as AReln (Sql tab, [r1])) :: hyps =>
                (case SM.find (!tabs, tab) of
                     NONE => findKeys (hyps, a :: acc)
                   | SOME (_, []) => findKeys (hyps, a :: acc)
                   | SOME (_, ks) =>
                     let
                         fun finder (hyps, acc) =
                             case hyps of
                                 [] => rev acc
                               | (a as AReln (Sql tab', [r2])) :: hyps =>
                                 if tab' = tab andalso
                                    List.exists (List.all (fn f =>
                                                              let
                                                                  val r =
                                                                      Cc.check (db,
                                                                                AReln (Cmp Eq, [Proj (r1, f),
                                                                                            Proj (r2, f)]))
                                                              in
                                                                  (*Print.prefaces "Fs"
                                                                                   [("tab",
                                                                                     Print.PD.string tab),
                                                                                    ("r1",
                                                                                     p_exp (Proj (r1, f))),
                                                                                    ("r2",
                                                                                     p_exp (Proj (r2, f))),
                                                                                    ("r",
                                                                                     Print.PD.string
                                                                                         (Bool.toString r))];*)
                                                                  r
                                                              end)) ks then
                                     (changed := true;
                                      Cc.assert (db, AReln (Cmp Eq, [r1, r2]));
                                      finder (hyps, acc))
                                 else
                                     finder (hyps, a :: acc)
                               | a :: hyps => finder (hyps, a :: acc)

                         val hyps = finder (hyps, [])
                     in
                         findKeys (hyps, a :: acc)
                     end)
              | a :: hyps => findKeys (hyps, a :: acc)

        fun loop hs =
            let
                val hs = findKeys (hs, [])
            in
                if !changed then
                    (changed := false;
                     loop hs)
                else
                    ()
            end

        val (_, hs, _) = !hyps
    in
        (*print "useKeys\n";*)
        loop hs
    end

fun complete () =
    let
        val (_, _, bf) = !hyps
    in
        if !bf then
            ()
        else
            (bf := true;
             useKeys ())
    end

type stashed = int * ((int * atom list) * check) option ref list * (int * atom list)
fun stash () = (!nvar, !path, (#1 (!hyps), #2 (!hyps)))
fun reinstate (nv, p, h) =
    (nvar := nv;
     path := p;
     setHyps h)

type stashedPath = ((int * atom list) * check) option ref list
fun stashPath () = !path
fun reinstatePath p = path := p

fun nextVar () =
    let
        val n = !nvar
    in
        nvar := n + 1;
        n
    end

fun assert ats =
    let
        val n = !hnames
        val (_, hs, _) = !hyps
    in
        hnames := n + 1;
        hyps := (n, ats @ hs, ref false);
        app (fn a => Cc.assert (db, a)) ats
    end

fun addPath c = path := ref (SOME ((#1 (!hyps), #2 (!hyps)), c)) :: !path

val sendable = ref ([] : (atom list * exp list) list)

fun checkGoals goals k =
    let
        fun checkGoals goals unifs =
            case goals of
                [] => k unifs
              | AReln (Sql tab, [Lvar lv]) :: goals =>
                let
                    val saved = stash ()
                    val (_, hyps, _) = !hyps

                    fun tryAll unifs hyps =
                        case hyps of
                            [] => false
                          | AReln (Sql tab', [e]) :: hyps =>
                            (tab' = tab andalso
                             checkGoals goals (IM.insert (unifs, lv, e)))
                            orelse tryAll unifs hyps
                          | _ :: hyps => tryAll unifs hyps
                in
                    tryAll unifs hyps
                end
              | (g as AReln (r, es)) :: goals =>
                (complete ();
                 (if Cc.check (db, AReln (r, map (simplify unifs) es)) then
                      true
                  else
                      ((*Print.preface ("Fail", p_atom (AReln (r, map (simplify unifs) es)));*)
                       false))
                 andalso checkGoals goals unifs)
              | ACond _ :: _ => false
    in
        checkGoals goals IM.empty
    end

fun buildable (e, loc) =
    let
        fun doPols pols acc =
            case pols of
                [] =>
                let
                    val b = Cc.builtFrom (db, {Base = acc, Derived = e})
                in
                    (*Print.prefaces "buildable" [("Base", Print.p_list p_exp acc),
                                                ("Derived", p_exp e),
                                                ("Hyps", Print.p_list p_atom (#2 (!hyps))),
                                                ("Good", Print.PD.string (Bool.toString b))];*)
                    b
                end
              | (goals, es) :: pols =>
                checkGoals goals (fn unifs => doPols pols (map (simplify unifs) es @ acc))
                orelse doPols pols acc
    in
        if doPols (!sendable) [] then
            ()
        else
            let
                val (_, hs, _) = !hyps
            in
                ErrorMsg.errorAt loc "The information flow policy may be violated here.";
                Print.prefaces "Situation" [("User learns", p_exp e),
                                            ("Hypotheses", Print.p_list p_atom hs),
                                            ("E-graph", Cc.p_database db)]
            end
    end

fun checkPaths () =
    let
        val (n, hs, _) = !hyps
        val hs = (n, hs)
    in
        app (fn r =>
                case !r of
                    NONE => ()
                  | SOME (hs, e) =>
                    (r := NONE;
                     setHyps hs;
                     buildable e)) (!path);
        setHyps hs
    end

fun allowSend v = ((*Print.prefaces "Allow" [("goals", Print.p_list p_atom (#1 v)),
                                           ("exps", Print.p_list p_exp (#2 v))];*)
                   sendable := v :: !sendable)

fun send (e, loc) = ((*Print.preface ("Send[" ^ Bool.toString uk ^ "]", p_exp e);*)
                     complete ();
                     checkPaths ();
                     if isKnown e then
                         ()
                     else
                         buildable (e, loc))

fun doable pols (loc : ErrorMsg.span) =
    let
        val pols = !pols
    in
        complete ();
        if List.exists (fn goals =>
                           if checkGoals goals (fn _ => true) then
                               ((*Print.prefaces "Match" [("goals", Print.p_list p_atom goals),
                                                        ("hyps", Print.p_list p_atom (#2 (!hyps)))];*)
                                true)
                           else
                               ((*Print.prefaces "No match" [("goals", Print.p_list p_atom goals)(*,
                                                           ("hyps", Print.p_list p_atom (#2 (!hyps)))*)];*)
                                false)) pols then
            ()
        else
            let
                val (_, hs, _) = !hyps
            in
                ErrorMsg.errorAt loc "The database update policy may be violated here.";
                Print.prefaces "Situation" [("Hypotheses", Print.p_list p_atom hs)(*,
                                            ("E-graph", Cc.p_database db)*)]
            end
    end

val insertable = ref ([] : atom list list)
fun allowInsert v = insertable := v :: !insertable
val insert = doable insertable

val updatable = ref ([] : atom list list)
fun allowUpdate v = updatable := v :: !updatable
val update = doable updatable

val deletable = ref ([] : atom list list)
fun allowDelete v = deletable := v :: !deletable
val delete = doable deletable

fun reset () = (Cc.clear db;
                path := [];
                hyps := (0, [], ref false);
                nvar := 0;
                sendable := [];
                insertable := [];
                updatable := [];
                deletable := [])

fun havocReln r =
    let
        val n = !hnames
        val (_, hs, _) = !hyps
    in
        hnames := n + 1;
        hyps := (n, List.filter (fn AReln (r', _) => r' <> r | _ => true) hs, ref false)
    end

fun havocCookie cname =
    let
        val cname = "cookie/" ^ cname
        val n = !hnames
        val (_, hs, _) = !hyps
    in
        hnames := n + 1;
        hyps := (n, List.filter (fn AReln (Cmp Eq, [_, Func (Other f, [])]) => f <> cname | _ => true) hs, ref false)
    end

fun check a = Cc.check (db, a)

fun debug () =
    let
        val (_, hs, _) = !hyps
    in
        Print.preface ("Hyps", Print.p_list p_atom hs)
    end

end


fun removeDups (ls : (string * string) list) =
    case ls of
        [] => []
      | x :: ls =>
        let
            val ls = removeDups ls
        in
            if List.exists (fn x' => x' = x) ls then
                ls
            else
                x :: ls
        end

fun deinj env e =
    case #1 e of
        ERel n => SOME (List.nth (env, n))
      | EField (e, f) =>
        (case deinj env e of
             NONE => NONE
           | SOME e => SOME (Proj (e, f)))
      | EApp ((EFfi mf, _), e) =>
        if Settings.isEffectful mf orelse Settings.isBenignEffectful mf then
            NONE
        else (case deinj env e of
                  NONE => NONE
                | SOME e => SOME (Func (Other (#1 mf ^ "." ^ #2 mf), [e])))
      | _ => NONE

fun expIn rv env rvOf =
    let
        fun expIn e =
            let
                fun default () = inl (rv ())
            in
                case e of
                    SqConst p => inl (Const p)
                  | SqTrue => inl (Func (DtCon0 "Basis.bool.True", []))
                  | SqFalse => inl (Func (DtCon0 "Basis.bool.False", []))
                  | Null => inl (Func (DtCon0 "None", []))
                  | SqNot e =>
                    inr (case expIn e of
                             inl e => Reln (Cmp Eq, [e, Func (DtCon0 "Basis.bool.False", [])])
                           | inr _ => Unknown)
                  | Field (v, f) => inl (Proj (rvOf v, f))
                  | Computed _ => default ()
                  | Binop (bo, e1, e2) =>
                    let
                        val e1 = expIn e1
                        val e2 = expIn e2
                    in
                        inr (case (bo, e1, e2) of
                                 (RCmp c, inl e1, inl e2) => Reln (Cmp c, [e1, e2])
                               | (RLop l, v1, v2) =>
                                 let
                                     fun pin v =
                                         case v of
                                             inl e => Reln (Cmp Eq, [e, Func (DtCon0 "Basis.bool.True", [])])
                                           | inr p => p
                                 in
                                     Lop (l, pin v1, pin v2)
                                 end
                               | _ => Unknown)
                    end
                  | SqKnown e =>
                    (case expIn e of
                         inl e => inr (Reln (Known, [e]))
                       | _ => inr Unknown)
                  | Inj e =>
                    inl (case deinj env e of
                             NONE => rv ()
                           | SOME e => e)
                  | SqFunc (f, e) =>
                    (case expIn e of
                         inl e => inl (Func (Other f, [e]))
                       | _ => default ())

                  | Unmodeled => inl (Func (Other "allow", [rv ()]))
            end
    in
        expIn
    end

fun decomp {Save = save, Restore = restore, Add = add} =
    let
        fun go p k =
            case p of
                True => (k () handle Cc.Contradiction => ())
              | False => ()
              | Unknown => ()
              | Lop (And, p1, p2) => go p1 (fn () => go p2 k)
              | Lop (Or, p1, p2) =>
                let
                    val saved = save ()
                in
                    go p1 k;
                    restore saved;
                    go p2 k
                end
              | Reln x => (add (AReln x); k ())
              | Cond x => (add (ACond x); k ())
    in
        go
    end

datatype queryMode =
         SomeCol of {New : (string * exp) option, Old : (string * exp) option, Outs : exp list} -> unit
       | AllCols of exp -> unit

type 'a doQuery = {
     Env : exp list,
     NextVar : unit -> exp,
     Add : atom -> unit,
     Save : unit -> 'a,
     Restore : 'a -> unit,
     Cont : queryMode
}

fun doQuery (arg : 'a doQuery) (e as (_, loc)) =
    let
        fun default () = (ErrorMsg.errorAt loc "Information flow checker can't parse SQL query";
                          Print.preface ("Query", MonoPrint.p_exp MonoEnv.empty e))
    in
        case parse query e of
            NONE => default ()
          | SOME q =>
            let
                fun doQuery q =
                    case q of
                        Query1 r =>
                        let
                            val new = ref NONE
                            val old = ref NONE

                            val rvs = map (fn Table (tab, v) =>
                                              let
                                                  val nv = #NextVar arg ()
                                              in
                                                  case v of
                                                      "New" => new := SOME (tab, nv)
                                                    | "Old" => old := SOME (tab, nv)
                                                    | _ => ();
                                                  (v, nv)
                                              end
                                            | _ => raise Fail "Iflow: not ready for joins or nesteds") (#From r)

                            fun rvOf v =
                                case List.find (fn (v', _) => v' = v) rvs of
                                    NONE => raise Fail "Iflow.queryProp: Bad table variable"
                                  | SOME (_, e) => e

                            val expIn = expIn (#NextVar arg) (#Env arg) rvOf

                            val saved = #Save arg ()
                            fun addFrom () = app (fn Table (t, v) => #Add arg (AReln (Sql t, [rvOf v]))
                                                   | _ => raise Fail "Iflow: not ready for joins or nesteds") (#From r)

                            fun usedFields e =
                                case e of
                                    SqConst _ => []
                                  | SqTrue => []
                                  | SqFalse => []
                                  | Null => []
                                  | SqNot e => usedFields e
                                  | Field (v, f) => [(false, Proj (rvOf v, f))]
                                  | Computed _ => []
                                  | Binop (_, e1, e2) => usedFields e1 @ usedFields e2
                                  | SqKnown _ => []
                                  | Inj e =>
                                    (case deinj (#Env arg) e of
                                         NONE => (ErrorMsg.errorAt loc "Expression injected into SQL is too complicated";
                                                  [])
                                       | SOME e => [(true, e)])
                                  | SqFunc (_, e) => usedFields e
                                  | Unmodeled => []

                            fun normal' () =
                                case #Cont arg of
                                    SomeCol k =>
                                    let
                                        val sis = map (fn si =>
                                                          case si of
                                                              SqField (v, f) => Proj (rvOf v, f)
                                                            | SqExp (e, f) =>
                                                              case expIn e of
                                                                  inr _ => #NextVar arg ()
                                                                | inl e => e) (#Select r)
                                    in
                                        k {New = !new, Old = !old, Outs = sis}
                                    end
                                  | AllCols k =>
                                    let
                                        val (ts, es) =
                                            foldl (fn (si, (ts, es)) =>
                                                      case si of
                                                          SqField (v, f) =>
                                                          let
                                                              val fs = getOpt (SM.find (ts, v), SM.empty)
                                                          in
                                                              (SM.insert (ts, v, SM.insert (fs, f, Proj (rvOf v, f))), es)
                                                          end
                                                        | SqExp (e, f) =>
                                                          let
                                                              val e =
                                                                  case expIn e of
                                                                      inr _ => #NextVar arg ()
                                                                    | inl e => e
                                                          in
                                                              (ts, SM.insert (es, f, e))
                                                          end)
                                                  (SM.empty, SM.empty) (#Select r)
                                    in
                                        k (Recd (map (fn (t, fs) => (t, Recd (SM.listItemsi fs)))
                                                     (SM.listItemsi ts)
                                                 @ SM.listItemsi es))
                                    end

                            fun doWhere final =
                                (addFrom ();
                                 case #Where r of
                                     NONE => final ()
                                   | SOME e =>
                                     let
                                         val p = case expIn e of
                                                     inl e => Reln (Cmp Eq, [e, Func (DtCon0 "Basis.bool.True", [])])
                                                   | inr p => p

                                         val saved = #Save arg ()
                                     in
                                         decomp {Save = #Save arg, Restore = #Restore arg, Add = #Add arg}
                                                p (fn () => final () handle Cc.Contradiction => ());
                                         #Restore arg saved
                                     end)
                                handle Cc.Contradiction => ()

                            fun normal () = doWhere normal'
                        in
                            (case #Select r of
                                 [SqExp (Binop (RCmp bo, Count, SqConst (Prim.Int 0)), f)] =>
                                 (case bo of
                                      Gt =>
                                      (case #Cont arg of
                                           SomeCol _ => ()
                                         | AllCols k =>
                                           let
                                               fun answer e = k (Recd [(f, e)])

                                               val saved = #Save arg ()
                                               val () = (answer (Func (DtCon0 "Basis.bool.False", [])))
                                                        handle Cc.Contradiction => ()
                                           in
                                               #Restore arg saved;
                                               (*print "True time!\n";*)
                                               doWhere (fn () => answer (Func (DtCon0 "Basis.bool.True", [])));
                                               #Restore arg saved
                                           end)
                                    | _ => normal ())
                               | _ => normal ())
                            before #Restore arg saved
                        end
                      | Union (q1, q2) =>
                        let
                            val saved = #Save arg ()
                        in
                            doQuery q1;
                            #Restore arg saved;
                            doQuery q2;
                            #Restore arg saved
                        end
            in
                doQuery q
            end
    end

fun evalPat env e (pt, _) =
    case pt of
        PWild => env
      | PVar _ => e :: env
      | PPrim _ => env
      | PCon (_, pc, NONE) => (St.assert [AReln (PCon0 (patCon pc), [e])]; env)
      | PCon (_, pc, SOME pt) =>
        let
            val env = evalPat env (Func (UnCon (patCon pc), [e])) pt
        in
            St.assert [AReln (PCon1 (patCon pc), [e])];
            env
        end
      | PRecord xpts =>
        foldl (fn ((x, pt, _), env) => evalPat env (Proj (e, x)) pt) env xpts
      | PNone _ => (St.assert [AReln (PCon0 "None", [e])]; env)
      | PSome (_, pt) =>
        let
            val env = evalPat env (Func (UnCon "Some", [e])) pt
        in
            St.assert [AReln (PCon1 "Some", [e])];
            env
        end

datatype arg_mode = Fixed | Decreasing | Arbitrary
type rfun = {args : arg_mode list, tables : SS.set, cookies : SS.set, body : Mono.exp}
val rfuns = ref (IM.empty : rfun IM.map)

fun evalExp env (e as (_, loc)) k =
    let
        (*val () = St.debug ()*)
        (*val () = Print.preface ("evalExp", MonoPrint.p_exp MonoEnv.empty e)*)

        fun default () = k (Var (St.nextVar ()))

        fun doFfi (m, s, es) =
            if m = "Basis" andalso SS.member (writers, s) then
                let
                    fun doArgs es =
                        case es of
                            [] =>
                            (if s = "set_cookie" then
                                 case es of
                                     [_, (cname, _), _, _, _] =>
                                     (case #1 cname of
                                          EPrim (Prim.String (_, cname)) =>
                                          St.havocCookie cname
                                        | _ => ())
                                   | _ => ()
                             else
                                 ();
                             k (Recd []))
                          | (e, _) :: es =>
                            evalExp env e (fn e => (St.send (e, loc); doArgs es))
                in
                    doArgs es
                end
            else if Settings.isEffectful (m, s) andalso not (Settings.isBenignEffectful (m, s)) then
                default ()
            else
                let
                    fun doArgs (es, acc) =
                        case es of
                            [] => k (Func (Other (m ^ "." ^ s), rev acc))
                          | (e, _) :: es =>
                            evalExp env e (fn e => doArgs (es, e :: acc))
                in
                    doArgs (es, [])
                end
    in
        case #1 e of
            EPrim p => k (Const p)
          | ERel n => k (List.nth (env, n))
          | ENamed _ => default ()
          | ECon (_, pc, NONE) => k (Func (DtCon0 (patCon pc), []))
          | ECon (_, pc, SOME e) => evalExp env e (fn e => k (Func (DtCon1 (patCon pc), [e])))
          | ENone _ => k (Func (DtCon0 "None", []))
          | ESome (_, e) => evalExp env e (fn e => k (Func (DtCon1 "Some", [e])))
          | EFfi _ => default ()

          | EFfiApp ("Basis", "rand", []) =>
            let
                val e = Var (St.nextVar ())
            in
                St.assert [AReln (Known, [e])];
                k e
            end
          | EFfiApp x => doFfi x
          | EApp ((EFfi (m, s), _), e) => doFfi (m, s, [(e, (TRecord [], loc))])

          | EApp (e1 as (EError _, _), _) => evalExp env e1 k

          | EApp (e1, e2) =>
            let
                fun adefault () = (ErrorMsg.errorAt loc "Excessively fancy function call";
                                   Print.preface ("Call", MonoPrint.p_exp MonoEnv.empty e);
                                   default ())

                fun doArgs (e, args) =
                    case #1 e of
                        EApp (e1, e2) => doArgs (e1, e2 :: args)
                      | ENamed n =>
                        (case IM.find (!rfuns, n) of
                             NONE => adefault ()
                           | SOME rf =>
                             if length (#args rf) <> length args then
                                 adefault ()
                             else
                                 let
                                     val () = (SS.app (St.havocReln o Sql) (#tables rf);
                                               SS.app St.havocCookie (#cookies rf))
                                     val saved = St.stash ()

                                     fun doArgs (args, modes, env') =
                                         case (args, modes) of
                                             ([], []) => (evalExp env' (#body rf) (fn _ => ());
                                                          St.reinstate saved;
                                                          default ())

                                           | (arg :: args, mode :: modes) =>
                                             evalExp env arg (fn arg =>
                                                                 let
                                                                     val v = case mode of
                                                                                 Arbitrary => Var (St.nextVar ())
                                                                               | Fixed => arg
                                                                               | Decreasing =>
                                                                                 let
                                                                                     val v = Var (St.nextVar ())
                                                                                 in
                                                                                     if St.check (AReln (Known, [arg])) then
                                                                                         St.assert [(AReln (Known, [v]))]
                                                                                     else
                                                                                         ();
                                                                                     v
                                                                                 end
                                                                 in
                                                                     doArgs (args, modes, v :: env')
                                                                 end)
                                           | _ => raise Fail "Iflow.doArgs: Impossible"
                                 in
                                     doArgs (args, #args rf, [])
                                 end)
                          | _ => adefault ()
            in
                doArgs (e, [])
            end

          | EAbs _ => default ()
          | EUnop (s, e1) => evalExp env e1 (fn e1 => k (Func (Other s, [e1])))
          | EBinop (_, s, e1, e2) => evalExp env e1 (fn e1 => evalExp env e2 (fn e2 => k (Func (Other s, [e1, e2]))))
          | ERecord xets =>
            let
                fun doFields (xes, acc) =
                    case xes of
                        [] => k (Recd (rev acc))
                      | (x, e, _) :: xes =>
                        evalExp env e (fn e => doFields (xes, (x, e) :: acc))
            in
                doFields (xets, [])
            end
          | EField (e, s) => evalExp env e (fn e => k (Proj (e, s)))
          | ECase (e, pes, {result = res, ...}) =>
            evalExp env e (fn e =>
                              if List.all (fn (_, (EWrite (EPrim _, _), _)) => true
                                            | _ => false) pes then
                                  (St.send (e, loc);
                                   k (Recd []))
                              else
                                  (St.addPath (e, loc);
                                   app (fn (p, pe) =>
                                           let
                                               val saved = St.stash ()
                                           in
                                               let
                                                   val env = evalPat env e p
                                               in
                                                   evalExp env pe k;
                                                   St.reinstate saved
                                               end
                                               handle Cc.Contradiction => St.reinstate saved
                                           end) pes))
          | EStrcat (e1, e2) =>
            evalExp env e1 (fn e1 =>
                evalExp env e2 (fn e2 =>
                                   k (Func (Other "cat", [e1, e2]))))
          | EError (e, _) => evalExp env e (fn e => St.send (e, loc))
          | EReturnBlob {blob = NONE, ...} => raise Fail "Iflow doesn't support blob optimization"
          | EReturnBlob {blob = SOME b, mimeType = m, ...} =>
            evalExp env b (fn b =>
                              (St.send (b, loc);
                               evalExp env m
                               (fn m => St.send (m, loc))))
          | ERedirect (e, _) =>
            evalExp env e (fn e => St.send (e, loc))
          | EWrite e =>
            evalExp env e (fn e => (St.send (e, loc);
                                    k (Recd [])))
          | ESeq (e1, e2) =>
            let
                val path = St.stashPath ()
            in
                evalExp env e1 (fn _ => (St.reinstatePath path; evalExp env e2 k))
            end
          | ELet (_, _, e1, e2) =>
            evalExp env e1 (fn e1 => evalExp (e1 :: env) e2 k)
          | EClosure (n, es) =>
            let
                fun doArgs (es, acc) =
                    case es of
                        [] => k (Func (Other ("Cl" ^ Int.toString n), rev acc))
                      | e :: es =>
                        evalExp env e (fn e => doArgs (es, e :: acc))
            in
                doArgs (es, [])
            end

          | EQuery {query = q, body = b, initial = i, state = state, ...} =>
            evalExp env i (fn i =>
                              let
                                  val r = Var (St.nextVar ())
                                  val acc = Var (St.nextVar ())

                                  val (ts, cs) = MonoUtil.Exp.fold {typ = fn (_, st) => st,
                                                                   exp = fn (e, st as (cs, ts)) =>
                                                                            case e of
                                                                                EDml (e, _) =>
                                                                                (case parse dml e of
                                                                                     NONE => st
                                                                                   | SOME c =>
                                                                                     case c of
                                                                                         Insert _ => st
                                                                                       | Delete (tab, _) =>
                                                                                         (cs, SS.add (ts, tab))
                                                                                       | Update (tab, _, _) =>
                                                                                         (cs, SS.add (ts, tab)))
                                                                              | EFfiApp ("Basis", "set_cookie",
                                                                                         [_, ((EPrim (Prim.String (_, cname)), _), _),
                                                                                          _, _, _]) =>
                                                                                (SS.add (cs, cname), ts)
                                                                              | _ => st}
                                                                  (SS.empty, SS.empty) b
                              in
                                  case (#1 state, SS.isEmpty ts, SS.isEmpty cs) of
                                          (TRecord [], true, true) => ()
                                        | _ =>
                                          let
                                              val saved = St.stash ()
                                          in
                                              (k i)
                                              handle Cc.Contradiction => ();
                                              St.reinstate saved
                                          end;

                                  SS.app (St.havocReln o Sql) ts;
                                  SS.app St.havocCookie cs;

                                  doQuery {Env = env,
                                           NextVar = Var o St.nextVar,
                                           Add = fn a => St.assert [a],
                                           Save = St.stash,
                                           Restore = St.reinstate,
                                           Cont = AllCols (fn x =>
                                                              (St.assert [AReln (Cmp Eq, [r, x])];
                                                               evalExp (acc :: r :: env) b k))} q
                              end)
          | EDml (e, _) =>
            (case parse dml e of
                 NONE => (print ("Warning: Information flow checker can't parse DML command at "
                                 ^ ErrorMsg.spanToString loc ^ "\n");
                          default ())
               | SOME d =>
                 case d of
                     Insert (tab, es) =>
                     let
                         val new = St.nextVar ()

                         val expIn = expIn (Var o St.nextVar) env
                                           (fn _ => raise Fail "Iflow.evalExp: Bad field expression in INSERT [1]")

                         val es = map (fn (x, e) =>
                                          case expIn e of
                                              inl e => (x, e)
                                            | inr _ => raise Fail "Iflow.evalExp: Bad field expression in INSERT [2]")
                                  es

                         val saved = St.stash ()
                     in
                         St.assert [AReln (Sql (tab ^ "$New"), [Recd es])];
                         St.insert loc;
                         St.reinstate saved;
                         St.assert [AReln (Sql tab, [Recd es])];
                         k (Recd [])
                     end
                   | Delete (tab, e) =>
                     let
                         val old = St.nextVar ()

                         val expIn = expIn (Var o St.nextVar) env
                                           (fn "T" => Var old
                                             | _ => raise Fail "Iflow.evalExp: Bad field expression in DELETE")

                         val p = case expIn e of
                                     inl e => raise Fail "Iflow.evalExp: DELETE with non-boolean"
                                   | inr p => p

                         val saved = St.stash ()
                     in
                         St.assert [AReln (Sql (tab ^ "$Old"), [Var old]),
                                    AReln (Sql (tab), [Var old])];
                         decomp {Save = St.stash,
                                 Restore = St.reinstate,
                                 Add = fn a => St.assert [a]} p
                                (fn () => (St.delete loc;
                                           St.reinstate saved;
                                           St.havocReln (Sql tab);
                                           k (Recd []))
                                    handle Cc.Contradiction => ())
                     end
                   | Update (tab, fs, e) =>
                     let
                         val new = St.nextVar ()
                         val old = St.nextVar ()

                         val expIn = expIn (Var o St.nextVar) env
                                           (fn "T" => Var old
                                             | _ => raise Fail "Iflow.evalExp: Bad field expression in UPDATE")

                         val fs = map
                                      (fn (x, e) =>
                                          (x, case expIn e of
                                                  inl e => e
                                                | inr _ => raise Fail
                                                                     ("Iflow.evalExp: Selecting "
                                                                      ^ "boolean expression")))
                                      fs

                         val fs' = case SM.find (!tabs, tab) of
                                       NONE => raise Fail "Iflow.evalExp: Updating unknown table"
                                     | SOME (fs', _) => fs'

                         val fs = foldl (fn (f, fs) =>
                                            if List.exists (fn (f', _) => f' = f) fs then
                                                fs
                                            else
                                                (f, Proj (Var old, f)) :: fs) fs fs'

                         val p = case expIn e of
                                           inl e => raise Fail "Iflow.evalExp: UPDATE with non-boolean"
                                         | inr p => p
                         val saved = St.stash ()
                     in
                         St.assert [AReln (Sql (tab ^ "$New"), [Recd fs]),
                                    AReln (Sql (tab ^ "$Old"), [Var old]),
                                    AReln (Sql tab, [Var old])];
                         decomp {Save = St.stash,
                                 Restore = St.reinstate,
                                 Add = fn a => St.assert [a]} p
                                (fn () => (St.update loc;
                                           St.reinstate saved;
                                           St.havocReln (Sql tab);
                                           k (Recd []))
                                    handle Cc.Contradiction => ())
                     end)

          | ENextval (EPrim (Prim.String (_, seq)), _) =>
            let
                val nv = St.nextVar ()
            in
                St.assert [AReln (Sql (String.extract (seq, 3, NONE)), [Var nv])];
                k (Var nv)
            end
          | ENextval _ => default ()
          | ESetval _ => default ()

          | EUnurlify ((EFfiApp ("Basis", "get_cookie", [((EPrim (Prim.String (_, cname)), _), _)]), _), _, _) =>
            let
                val e = Var (St.nextVar ())
                val e' = Func (Other ("cookie/" ^ cname), [])
            in
                St.assert [AReln (Known, [e]), AReln (Cmp Eq, [e, e'])];
                k e
            end

          | EUnurlify _ => default ()
          | EJavaScript _ => default ()
          | ESignalReturn _ => default ()
          | ESignalBind _ => default ()
          | ESignalSource _ => default ()
          | EServerCall _ => default ()
          | ERecv _ => default ()
          | ESleep _ => default ()
          | ESpawn _ => default ()
    end

datatype var_source = Input of int | SubInput of int | Unknown

structure U = MonoUtil

fun mliftExpInExp by =
    U.Exp.mapB {typ = fn t => t,
                exp = fn bound => fn e =>
                                     case e of
                                         ERel xn =>
                                         if xn < bound then
                                             e
                                         else
                                             ERel (xn + by)
                                       | _ => e,
                bind = fn (bound, U.Exp.RelE _) => bound + 1
                        | (bound, _) => bound}

fun nameSubexps k (e : Mono.exp) =
    let
        fun numParams (e : Mono.exp) =
            case #1 e of
                EStrcat (e1, e2) => numParams e1 + numParams e2
              | EPrim (Prim.String _) => 0
              | _ => 1

        val nps = numParams e

        fun getParams (e : Mono.exp) x =
            case #1 e of
                EStrcat (e1, e2) =>
                let
                    val (ps1, e1') = getParams e1 x
                    val (ps2, e2') = getParams e2 (x - length ps1)
                in
                    (ps2 @ ps1, (EStrcat (e1', e2'), #2 e))
                end
              | EPrim (Prim.String _) => ([], e)
              | _ =>
                let
                    val (e', k) =
                        case #1 e of
                            EFfiApp (m, f, [(e', t)]) =>
                            if Settings.isEffectful (m, f) orelse Settings.isBenignEffectful (m, f) then
                                (e, fn x => x)
                            else
                                (e', fn e' => (EFfiApp (m, f, [(e', t)]), #2 e))
                          | ECase (e', ps as
                                          [((PCon (_, PConFfi {mod = "Basis", con = "True", ...}, NONE), _),
                                            (EPrim (Prim.String (_, "TRUE")), _)),
                                           ((PCon (_, PConFfi {mod = "Basis", con = "False", ...}, NONE), _),
                                            (EPrim (Prim.String (_, "FALSE")), _))], q) =>
                            (e', fn e' => (ECase (e', ps, q), #2 e))
                          | _ => (e, fn x => x)
                in
                    ([e'], k (ERel x, #2 e))
                end

        val (ps, e') = getParams e (nps - 1)

        val string = (TFfi ("Basis", "string"), #2 e)

        val (e', _) = foldl (fn (p, (e', liftBy)) =>
                                ((ELet ("p" ^ Int.toString liftBy,
                                        string,
                                        mliftExpInExp liftBy 0 p,
                                        e'), #2 e), liftBy - 1)) (k (nps, e'), nps - 1) ps
    in
        #1 e'
    end

val namer = MonoUtil.File.map {typ = fn t => t,
                               exp = fn e =>
                                        case e of
                                            EDml (e, fm) =>
                                            nameSubexps (fn (_, e') => (EDml (e', fm), #2 e)) e
                                          | EQuery {exps, tables, state, query, body, initial} =>
                                            nameSubexps (fn (liftBy, e') =>
                                                            (EQuery {exps = exps,
                                                                     tables = tables,
                                                                     state = state,
                                                                     query = e',
                                                                     body = mliftExpInExp liftBy 2 body,
                                                                     initial = mliftExpInExp liftBy 0 initial},
                                                             #2 query)) query
                                          | _ => e,
                                     decl = fn d => d}

fun check (file : file) =
    let
        val () = (St.reset ();
                  rfuns := IM.empty)

        (*val () = Print.preface ("FilePre", MonoPrint.p_file MonoEnv.empty file)*)
        val file = MonoReduce.reduce file
        val file = MonoOpt.optimize file
        val file = Fuse.fuse file
        val file = MonoOpt.optimize file
        val file = MonoShake.shake file
        val file = namer file
        (*val () = Print.preface ("File", MonoPrint.p_file MonoEnv.empty file)*)

        val exptd = foldl (fn ((d, _), exptd) =>
                              case d of
                                  DExport (_, _, n, _, _, _) => IS.add (exptd, n)
                                | _ => exptd) IS.empty (#1 file)

        fun decl (d, loc) =
            case d of
                DTable (tab, fs, pk, _) =>
                let
                    val ks =
                        case #1 pk of
                            EPrim (Prim.String (_, s)) =>
                            (case String.tokens (fn ch => ch = #"," orelse ch = #" ") s of
                                 [] => []
                               | pk => [pk])
                          | _ => []
                in
                    if size tab >= 3 then
                        tabs := SM.insert (!tabs, String.extract (tab, 3, NONE),
                                           (map #1 fs,
                                            map (map (fn s => str (Char.toUpper (String.sub (s, 3)))
                                                              ^ String.extract (s, 4, NONE))) ks))
                    else
                        raise Fail "Table name does not begin with uw_"
                end
              | DVal (x, n, _, e, _) =>
                let
                    (*val () = print ("\n=== " ^ x ^ " ===\n\n");*)

                    val isExptd = IS.member (exptd, n)

                    val saved = St.stash ()

                    fun deAbs (e, env, ps) =
                        case #1 e of
                            EAbs (_, _, _, e) =>
                            let
                                val nv = Var (St.nextVar ())
                            in
                                deAbs (e, nv :: env,
                                       if isExptd then
                                           AReln (Known, [nv]) :: ps
                                       else
                                           ps)
                            end
                          | _ => (e, env, ps)

                    val (e, env, ps) = deAbs (e, [], [])
                in
                    St.assert ps;
                    (evalExp env e (fn _ => ()) handle Cc.Contradiction => ());
                    St.reinstate saved
                end

              | DValRec [(x, n, _, e, _)] =>
                let
                    val tables = ref SS.empty
                    val cookies = ref SS.empty

                    fun deAbs (e, env, modes) =
                        case #1 e of
                            EAbs (_, _, _, e) => deAbs (e, Input (length env) :: env, ref Fixed :: modes)
                          | _ => (e, env, rev modes)

                    val (e, env, modes) = deAbs (e, [], [])

                    fun doExp env (e as (_, loc)) =
                        case #1 e of
                            EPrim _ => e
                          | ERel _ => e
                          | ENamed _ => e
                          | ECon (_, _, NONE) => e
                          | ECon (dk, pc, SOME e) => (ECon (dk, pc, SOME (doExp env e)), loc)
                          | ENone _ => e
                          | ESome (t, e) => (ESome (t, doExp env e), loc)
                          | EFfi _ => e
                          | EFfiApp (m, f, es) =>
                            (case (m, f, es) of
                                 ("Basis", "set_cookie", [_, ((EPrim (Prim.String (_, cname)), _), _), _, _, _]) =>
                                 cookies := SS.add (!cookies, cname)
                               | _ => ();
                             (EFfiApp (m, f, map (fn (e, t) => (doExp env e, t)) es), loc))

                          | EApp (e1, e2) =>
                            let
                                fun default () = (EApp (doExp env e1, doExp env e2), loc)

                                fun explore (e, args) =
                                    case #1 e of
                                        EApp (e1, e2) => explore (e1, e2 :: args)
                                      | ENamed n' =>
                                        if n' = n then
                                            let
                                                fun doArgs (pos, args, modes) =
                                                    case (args, modes) of
                                                        ((e1, _) :: args, m1 :: modes) =>
                                                        (case e1 of
                                                             ERel n =>
                                                             (case List.nth (env, n) of
                                                                  Input pos' =>
                                                                  if pos' = pos then
                                                                      ()
                                                                  else
                                                                      m1 := Arbitrary
                                                                | SubInput pos' =>
                                                                  if pos' = pos then
                                                                      if !m1 = Arbitrary then
                                                                          ()
                                                                      else
                                                                          m1 := Decreasing
                                                                  else
                                                                      m1 := Arbitrary
                                                                | Unknown => m1 := Arbitrary)
                                                           | _ => m1 := Arbitrary;
                                                         doArgs (pos + 1, args, modes))
                                                      | (_ :: _, []) => ()
                                                      | ([], ms) => app (fn m => m := Arbitrary) ms
                                            in
                                                doArgs (0, args, modes);
                                                (EFfi ("Basis", "?"), loc)
                                            end
                                        else
                                            default ()
                                      | _ => default ()
                            in
                                explore (e, [])
                            end
                          | EAbs (x, t1, t2, e) => (EAbs (x, t1, t2, doExp (Unknown :: env) e), loc)
                          | EUnop (uo, e1) => (EUnop (uo, doExp env e1), loc)
                          | EBinop (bi, bo, e1, e2) => (EBinop (bi, bo, doExp env e1, doExp env e2), loc)
                          | ERecord xets => (ERecord (map (fn (x, e, t) => (x, doExp env e, t)) xets), loc)
                          | EField (e1, f) => (EField (doExp env e1, f), loc)
                          | ECase (e, pes, ts) =>
                            let
                                val source =
                                    case #1 e of
                                        ERel n =>
                                        (case List.nth (env, n) of
                                             Input n => SOME n
                                           | SubInput n => SOME n
                                           | Unknown => NONE)
                                      | _ => NONE

                                fun doV v =
                                    let
                                        fun doPat (p, env) =
                                            case #1 p of
                                                PWild => env
                                              | PVar _ => v :: env
                                              | PPrim _ => env
                                              | PCon (_, _, NONE) => env
                                              | PCon (_, _, SOME p) => doPat (p, env)
                                              | PRecord xpts => foldl (fn ((_, p, _), env) => doPat (p, env)) env xpts
                                              | PNone _ => env
                                              | PSome (_, p) => doPat (p, env)
                                    in
                                        (ECase (e, map (fn (p, e) => (p, doExp (doPat (p, env)) e)) pes, ts), loc)
                                    end
                            in
                                case source of
                                    NONE => doV Unknown
                                  | SOME inp => doV (SubInput inp)
                            end
                          | EStrcat (e1, e2) => (EStrcat (doExp env e1, doExp env e2), loc)
                          | EError (e1, t) => (EError (doExp env e1, t), loc)
                          | EReturnBlob {blob = NONE, mimeType = m, t} =>
                            (EReturnBlob {blob = NONE, mimeType = doExp env m, t = t}, loc)
                          | EReturnBlob {blob = SOME b, mimeType = m, t} =>
                            (EReturnBlob {blob = SOME (doExp env b), mimeType = doExp env m, t = t}, loc)
                          | ERedirect (e1, t) => (ERedirect (doExp env e1, t), loc)
                          | EWrite e1 => (EWrite (doExp env e1), loc)
                          | ESeq (e1, e2) => (ESeq (doExp env e1, doExp env e2), loc)
                          | ELet (x, t, e1, e2) => (ELet (x, t, doExp env e1, doExp (Unknown :: env) e2), loc)
                          | EClosure (n, es) => (EClosure (n, map (doExp env) es), loc)
                          | EQuery {exps, tables, state, query, body, initial} =>
                            (EQuery {exps = exps, tables = tables, state = state,
                                     query = doExp env query,
                                     body = doExp (Unknown :: Unknown :: env) body,
                                     initial = doExp env initial}, loc)
                          | EDml (e1, mode) =>
                            (case parse dml e1 of
                                 NONE => ()
                               | SOME c =>
                                 case c of
                                     Insert _ => ()
                                   | Delete (tab, _) =>
                                     tables := SS.add (!tables, tab)
                                   | Update (tab, _, _) =>
                                     tables := SS.add (!tables, tab);
                             (EDml (doExp env e1, mode), loc))
                          | ENextval e1 => (ENextval (doExp env e1), loc)
                          | ESetval (e1, e2) => (ESetval (doExp env e1, doExp env e2), loc)
                          | EUnurlify (e1, t, b) => (EUnurlify (doExp env e1, t, b), loc)
                          | EJavaScript (m, e) => (EJavaScript (m, doExp env e), loc)
                          | ESignalReturn _ => e
                          | ESignalBind _ => e
                          | ESignalSource _ => e
                          | EServerCall _ => e
                          | ERecv _ => e
                          | ESleep _ => e
                          | ESpawn _ => e

                    val e = doExp env e
                in
                    rfuns := IM.insert (!rfuns, n, {tables = !tables, cookies = !cookies,
                                                    args = map (fn r => !r) modes, body = e})
                end

              | DValRec _ => ErrorMsg.errorAt loc "Iflow can't check mutually-recursive functions yet."

              | DPolicy pol =>
                let
                    val rvN = ref 0
                    fun rv () =
                        let
                            val n = !rvN
                        in
                            rvN := n + 1;
                            Lvar n
                        end

                    val atoms = ref ([] : atom list)
                    fun doQ k = doQuery {Env = [],
                                         NextVar = rv,
                                         Add = fn a => atoms := a :: !atoms,
                                         Save = fn () => !atoms,
                                         Restore = fn ls => atoms := ls,
                                         Cont = SomeCol (fn r => k (rev (!atoms), r))}

                    fun untab (tab, nams) = List.filter (fn AReln (Sql tab', [Lvar lv]) =>
                                                            tab' <> tab
                                                            orelse List.all (fn Lvar lv' => lv' <> lv
                                                                              | _ => false) nams
                                                          | _ => true)
                in
                    case pol of
                        PolClient e =>
                        doQ (fn (ats, {Outs = es, ...}) => St.allowSend (ats, es)) e
                      | PolInsert e =>
                        doQ (fn (ats, {New = SOME (tab, new), ...}) =>
                                St.allowInsert (AReln (Sql (tab ^ "$New"), [new]) :: untab (tab, [new]) ats)
                              | _ => raise Fail "Iflow: No New in mayInsert policy") e
                      | PolDelete e =>
                        doQ (fn (ats, {Old = SOME (tab, old), ...}) =>
                                St.allowDelete (AReln (Sql (tab ^ "$Old"), [old]) :: untab (tab, [old]) ats)
                              | _ => raise Fail "Iflow: No Old in mayDelete policy") e
                      | PolUpdate e =>
                        doQ (fn (ats, {New = SOME (tab, new), Old = SOME (_, old), ...}) =>
                                St.allowUpdate (AReln (Sql (tab ^ "$Old"), [old])
                                                :: AReln (Sql (tab ^ "$New"), [new])
                                                :: untab (tab, [new, old]) ats)
                              | _ => raise Fail "Iflow: No New or Old in mayUpdate policy") e
                      | PolSequence e =>
                        (case #1 e of
                             EPrim (Prim.String (_, seq)) =>
                             let
                                 val p = AReln (Sql (String.extract (seq, 3, NONE)), [Lvar 0])
                                 val outs = [Lvar 0]
                             in
                                 St.allowSend ([p], outs)
                             end
                           | _ => ())
                end

              | _ => ()
    in
        app decl (#1 file)
    end

val check = fn file =>
               let
                   val oldInline = Settings.getMonoInline ()
                   val oldFull = !MonoReduce.fullMode
               in
                   (Settings.setMonoInline (case Int.maxInt of
                                                NONE => 1000000
                                              | SOME n => n);
                    MonoReduce.fullMode := true;
                    check file;
                    Settings.setMonoInline oldInline)
                   handle ex => (Settings.setMonoInline oldInline;
                                 MonoReduce.fullMode := oldFull;
                                 raise ex)
               end

end