aboutsummaryrefslogtreecommitdiff
path: root/src/algebra/aggcat.spad.pamphlet
blob: 0515f143354b06d20f59c71da3ae51ce03226068 (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
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
\documentclass{article}
\usepackage{open-axiom}
\begin{document}
\title{src/algebra aggcat.spad}
\author{Michael Monagan, Manuel Bronstein, Richard Jenks, Stephen Watt}
\maketitle

\begin{abstract}
\end{abstract}

\tableofcontents
\eject

\section{category AGG Aggregate}

<<category AGG Aggregate>>=
import Type
import Boolean
import NonNegativeInteger
)abbrev category AGG Aggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ The notion of aggregate serves to model any data structure aggregate,
++ designating any collection of objects,
++ with heterogenous or homogeneous members,
++ with a finite or infinite number
++ of members, explicitly or implicitly represented.
++ An aggregate can in principle
++ represent everything from a string of characters to abstract sets such
++ as "the set of x satisfying relation {\em r(x)}"
Aggregate: Category == Type with
   eq?: (%,%) -> Boolean
     ++ eq?(u,v) tests if u and v are same objects.
   copy: % -> %
     ++ copy(u) returns a top-level (non-recursive) copy of u.
     ++ Note: for collections, \axiom{copy(u) == [x for x in u]}.
   empty: () -> %
     ++ empty()$D creates an aggregate of type D with 0 elements.
     ++ Note: The {\em $D} can be dropped if understood by context,
     ++ e.g. \axiom{u: D := empty()}.
   empty?: % -> Boolean
     ++ empty?(u) tests if u has 0 elements.
   sample: constant -> %    ++ sample yields a value of type %
 add
  eq?(a,b) == %peq(a,b)$Foreign(Builtin)
  sample() == empty()

@

\section{}

\section{category HOAGG HomogeneousAggregate}

<<category HOAGG HomogeneousAggregate>>=
import Boolean
import OutputForm
import SetCategory
import Aggregate
import CoercibleTo OutputForm
import Evalable
)abbrev category HOAGG HomogeneousAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991, May 1995
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A homogeneous aggregate is an aggregate of elements all of the
++ same type.
++ In the current system, all aggregates are homogeneous.
++ Two attributes characterize classes of aggregates.
++ Those with attribute \spadatt{shallowlyMutable} allow an element
++ to be modified or updated without changing its overall value.
HomogeneousAggregate(S:Type): Category == Aggregate with
   if S has CoercibleTo(OutputForm) then CoercibleTo(OutputForm)
   if S has BasicType then BasicType
   if S has SetCategory then SetCategory
   if S has SetCategory then
      if S has Evalable S then Evalable S
   map	   : (S->S,%) -> %
     ++ map(f,u) returns a copy of u with each element x replaced by f(x).
     ++ For collections, \axiom{map(f,u) = [f(x) for x in u]}.
   if % has shallowlyMutable then
     map!: (S->S,%) -> %
	++ map!(f,u) destructively replaces each element x of u by \axiom{f(x)}.
  add
   if S has Evalable S then
     eval(u:%,l:List Equation S):% == map(eval(#1,l),u)

@

\section{Aggregates of finite extent}

<<category FINAGG FiniteAggregate>>=
)abbrev category FINAGG FiniteAggregate
++ Author: Gabriel Dos Reis
++ Date Created: May 15, 2013
++ Date Last Modified: May 15, 2013
++ Description:
++   A finite aggregate is a homogeneous aggregate with a finite
++   number of elements.
FiniteAggregate(S: Type): Category == Exports where
  Exports == HomogeneousAggregate S with
      #: % -> NonNegativeInteger
        ++ \spad{#u} returns the number of items in u.
      any?: (S->Boolean,%) -> Boolean
        ++ \spad{any?(p,u)} tests if \spad{p(x)} is true for
        ++ any element \spad{x} of \spad{u}.
        ++ Note: for collections,
        ++ \axiom{any?(p,u) = reduce(or,map(f,u),false,true)}.
      every?: (S->Boolean,%) -> Boolean
        ++ \spad{every?(f,u)} tests if p(x) holds for all
        ++ elements \spad{x} of \spad{u}.
        ++ Note: for collections,
        ++ \axiom{every?(p,u) = reduce(and,map(f,u),true,false)}.
      count: (S->Boolean,%) -> NonNegativeInteger
        ++ \spad{count(p,u)} returns the number of elements \spad{x}
        ++  in \spad{u} such that \axiom{p(x)} holds. For collections,
        ++ \axiom{count(p,u) = reduce(+,[1 for x in u | p(x)],0)}.
      members: % -> List S
        ++ \spad{members(u)} returns a list of the consecutive elements of u.
        ++ For collections, \axiom{members([x,y,...,z]) = (x,y,...,z)}.
      reduce: ((S,S)->S,%) -> S
        ++ \spad{reduce(f,u)} reduces the binary operation \spad{f}
        ++ across \spad{u}. For example, if \spad{u} is \spad{[x,y,...,z]}
        ++ then \spad{reduce(f,u)} returns \spad{f(..f(f(x,y),...),z)}.
        ++ Note: if \spad{u} has one element \spad{x},
        ++ \spad{reduce(f,u)} returns \spad{x}. Error: if \spad{u} is empty.
      reduce: ((S,S)->S,%,S) -> S
        ++ \spad{reduce(f,u,x)} reduces the binary operation \spad{f}
        ++ across \spad{u}, where \spad{x} is the starting value, usually
        ++ the identity operation of \spad{f}. Same as
        ++ \spad{reduce(f,u)} if \spad{u} has 2 or more elements.
        ++ Returns \spad{f(x,y)} if \spad{u} has one element \spad{y},
        ++ \spad{x} if \spad{u} is empty.  For example,
        ++ \spad{reduce(+,u,0)} returns the sum of the elements of \spad{u}.
      if S has BasicType then
        count: (S,%) -> NonNegativeInteger
          ++ \spad{count(x,u)} returns the number of occurrences
          ++ of \spad{x} in \spad{u}.
          ++ For collections, \axiom{count(x,u) = reduce(+,[x=y for y in u],0)}.
        member?: (S,%) -> Boolean
          ++ \spad{member?(x,u)} tests if \spad{x} is a member of \spad{u}.
          ++ For collections,
          ++ \axiom{member?(x,u) = reduce(or,[x=y for y in u],false)}.
	reduce: ((S,S)->S,%,S,S) -> S
          ++ \spad{reduce(f,u,x,z)} reduces the binary operation \spad{f}
          ++ across \spad{u}, stopping when an "absorbing element"
          ++ \spad{z} is encountered.  As for \spad{reduce(f,u,x)},
          ++ \spad{x} is the identity operation of \spad{f}.
          ++ Same as \spad{reduce(f,u,x)} when \spad{u} contains no
          ++ element \spad{z}.  Thus the third argument \spad{x} is
          ++ returned when u is empty.
    add
      empty? x == #x = 0
      #x == # members x
      any?(f, x) == or/[f e for e in members x]
      every?(f, x) == and/[f e for e in members x]
      count(f:S -> Boolean, x:%) == +/[1 for e in members x | f e]
      if S has BasicType then
        count(s:S, x:%) == count(s = #1, x)
        member?(e, x)   == any?(e = #1,x)
        reduce(f,x,e,z) == reduce(f,members x,e,z)
        x = y == members x = members y
      if S has CoercibleTo OutputForm then
        coerce(x:%):OutputForm ==
          bracket
             commaSeparate [a::OutputForm for a in members x]$List(OutputForm)

@

\section{}

<<category SMAGG ShallowlyMutableAggregate>>=
)abbrev category SMAGG ShallowlyMutableAggregate
++ Author: Gabriel Dos Reis
++ Date Created: May 17, 2013
++ Date Last Created: May 17, 2013
++ Description:
++   This category describes the class of homogeneous aggregates
++   that support in place mutation that do not change their general
++   shapes.
ShallowlyMutableAggregate(S: Type): Category == Exports where
  Exports == HomogeneousAggregate S with
      shallowlyMutable -- FIXME: TEMPORARY.
      map!: (S->S,%) -> %
        ++ \spad{map!(f,u)} destructively replaces each element
        ++ \spad{x} of \spad{u} by \spad{f(x)}    

@



\section{category CLAGG Collection}

<<category CLAGG Collection>>=
import Boolean
import HomogeneousAggregate
)abbrev category CLAGG Collection
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A collection is a homogeneous aggregate which can built from
++ list of members. The operation used to build the aggregate is
++ generically named \spadfun{construct}. However, each collection
++ provides its own special function with the same name as the
++ data type, except with an initial lower case letter, e.g.
++ \spadfun{list} for \spadtype{List},
++ \spadfun{flexibleArray} for \spadtype{FlexibleArray}, and so on.
Collection(S:Type): Category == HomogeneousAggregate(S) with
   construct: List S -> %
     ++ \axiom{construct(x,y,...,z)} returns the collection of elements \axiom{x,y,...,z}
     ++ ordered as given. Equivalently written as \axiom{[x,y,...,z]$D}, where
     ++ D is the domain. D may be omitted for those of type List.
   find: (S->Boolean, %) -> Union(S, "failed")
     ++ find(p,u) returns the first x in u such that \axiom{p(x)} is true, and
     ++ "failed" otherwise.
   if % has FiniteAggregate S then
      remove: (S->Boolean,%) -> %
	++ remove(p,u) returns a copy of u removing all elements x such that
	++ \axiom{p(x)} is true.
	++ Note: \axiom{remove(p,u) == [x for x in u | not p(x)]}.
      select: (S->Boolean,%) -> %
	++ select(p,u) returns a copy of u containing only those elements such
	++ \axiom{p(x)} is true.
	++ Note: \axiom{select(p,u) == [x for x in u | p(x)]}.
      if S has BasicType then
	remove: (S,%) -> %
	  ++ remove(x,u) returns a copy of u with all
	  ++ elements \axiom{y = x} removed.
	  ++ Note: \axiom{remove(y,c) == [x for x in c | x ~= y]}.
	removeDuplicates: % -> %
	  ++ removeDuplicates(u) returns a copy of u with all duplicates removed.
   if S has ConvertibleTo InputForm then ConvertibleTo InputForm
 add
   if % has FiniteAggregate S then
     find(f:S -> Boolean, c:%) == find(f, members c)
     remove(f:S->Boolean, x:%) ==
       construct remove(f, members x)
     select(f:S->Boolean, x:%) ==
       construct select(f, members x)

     if S has BasicType then
       remove(s:S, x:%) == remove(#1 = s, x)
       removeDuplicates(x) == construct removeDuplicates members x

@

\section{category BGAGG BagAggregate}

<<category BGAGG BagAggregate>>=
import HomogeneousAggregate
import List
)abbrev category BGAGG BagAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A bag aggregate is an aggregate for which one can insert and extract objects,
++ and where the order in which objects are inserted determines the order
++ of extraction.
++ Examples of bags are stacks, queues, and dequeues.
BagAggregate(S:Type): Category == ShallowlyMutableAggregate S with
   bag: List S -> %
     ++ bag([x,y,...,z]) creates a bag with elements x,y,...,z.
   extract!: % -> S
     ++ extract!(u) destructively removes a (random) item from bag u.
   insert!: (S,%) -> %
     ++ insert!(x,u) inserts item x into bag u.
   inspect: % -> S
     ++ inspect(u) returns an (random) element from a bag.
 add
   bag(l) ==
     x:=empty()
     for s in l repeat x:=insert!(s,x)
     x

@

\section{category SKAGG StackAggregate}

<<category SKAGG StackAggregate>>=
import NonNegativeInteger
import BagAggregate
)abbrev category SKAGG StackAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A stack is a bag where the last item inserted is the first item extracted.
StackAggregate(S:Type): Category == Join(BagAggregate S,FiniteAggregate S) with
   push!: (S,%) -> S
     ++ push!(x,s) pushes x onto stack s, i.e. destructively changing s
     ++ so as to have a new first (top) element x.
     ++ Afterwards, pop!(s) produces x and pop!(s) produces the original s.
   pop!: % -> S
     ++ pop!(s) returns the top element x, destructively removing x from s.
     ++ Note: Use \axiom{top(s)} to obtain x without removing it from s.
     ++ Error: if s is empty.
   top: % -> S
     ++ top(s) returns the top element x from s; s remains unchanged.
     ++ Note: Use \axiom{pop!(s)} to obtain x and remove it from s.
   depth: % -> NonNegativeInteger
     ++ depth(s) returns the number of elements of stack s.
     ++ Note: \axiom{depth(s) = #s}.


@

\section{category QUAGG QueueAggregate}

<<category QUAGG QueueAggregate>>=
import NonNegativeInteger
import BagAggregate
)abbrev category QUAGG QueueAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A queue is a bag where the first item inserted is the first item extracted.
QueueAggregate(S:Type): Category == Join(BagAggregate S,FiniteAggregate S) with
   enqueue!: (S, %) -> S
     ++ enqueue!(x,q) inserts x into the queue q at the back end.
   dequeue!: % -> S
     ++ dequeue! s destructively extracts the first (top) element from queue q.
     ++ The element previously second in the queue becomes the first element.
     ++ Error: if q is empty.
   rotate!: % -> %
     ++ rotate! q rotates queue q so that the element at the front of
     ++ the queue goes to the back of the queue.
     ++ Note: rotate! q is equivalent to enqueue!(dequeue!(q)).
   length: % -> NonNegativeInteger
     ++ length(q) returns the number of elements in the queue.
     ++ Note: \axiom{length(q) = #q}.
   front: % -> S
     ++ front(q) returns the element at the front of the queue.
     ++ The queue q is unchanged by this operation.
     ++ Error: if q is empty.
   back: % -> S
     ++ back(q) returns the element at the back of the queue.
     ++ The queue q is unchanged by this operation.
     ++ Error: if q is empty.

@

\section{category DQAGG DequeueAggregate}

<<category DQAGG DequeueAggregate>>=
import StackAggregate
import QueueAggregate
)abbrev category DQAGG DequeueAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A dequeue is a doubly ended stack, that is, a bag where first items
++ inserted are the first items extracted, at either the front or the back end
++ of the data structure.
DequeueAggregate(S:Type):
 Category == Join(StackAggregate S,QueueAggregate S) with
   dequeue: () -> %
     ++ dequeue()$D creates an empty dequeue of type D.
   dequeue: List S -> %
     ++ dequeue([x,y,...,z]) creates a dequeue with first (top or front)
     ++ element x, second element y,...,and last (bottom or back) element z.
   height: % -> NonNegativeInteger
     ++ height(d) returns the number of elements in dequeue d.
     ++ Note: \axiom{height(d) = # d}.
   top!: % -> S
     ++ top!(d) returns the element at the top (front) of the dequeue.
   bottom!: % -> S
     ++ bottom!(d) returns the element at the bottom (back) of the dequeue.
   insertTop!: (S,%) -> S
     ++ insertTop!(x,d) destructively inserts x into the dequeue d, that is,
     ++ at the top (front) of the dequeue.
     ++ The element previously at the top of the dequeue becomes the
     ++ second in the dequeue, and so on.
   insertBottom!: (S,%) -> S
     ++ insertBottom!(x,d) destructively inserts x into the dequeue d
     ++ at the bottom (back) of the dequeue.
   extractTop!: % -> S
     ++ extractTop!(d) destructively extracts the top (front) element
     ++ from the dequeue d.
     ++ Error: if d is empty.
   extractBottom!: % -> S
     ++ extractBottom!(d) destructively extracts the bottom (back) element
     ++ from the dequeue d.
     ++ Error: if d is empty.
   reverse!: % -> %
     ++ reverse!(d) destructively replaces d by its reverse dequeue, i.e.
     ++ the top (front) element is now the bottom (back) element, and so on.

@

\section{category PRQAGG PriorityQueueAggregate}

<<category PRQAGG PriorityQueueAggregate>>=
import BagAggregate
)abbrev category PRQAGG PriorityQueueAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A priority queue is a bag of items from an ordered set where the item
++ extracted is always the maximum element.
PriorityQueueAggregate(S:OrderedSet): Category == Join(BagAggregate S,FiniteAggregate S) with
   max: % -> S
     ++ max(q) returns the maximum element of priority queue q.
   merge: (%,%) -> %
     ++ merge(q1,q2) returns combines priority queues q1 and q2 to return
     ++ a single priority queue q.
   merge!: (%,%) -> %
     ++ merge!(q,q1) destructively changes priority queue q to include the
     ++ values from priority queue q1.

@

\section{category DIOPS DictionaryOperations}
<<category DIOPS DictionaryOperations>>=
import Boolean
import Collection
import BagAggregate
)abbrev category DIOPS DictionaryOperations
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ This category is a collection of operations common to both
++ categories \spadtype{Dictionary} and \spadtype{MultiDictionary}
DictionaryOperations(S:SetCategory): Category ==
  Join(BagAggregate S, Collection(S)) with
   dictionary: () -> %
     ++ dictionary()$D creates an empty dictionary of type D.
   dictionary: List S -> %
     ++ dictionary([x,y,...,z]) creates a dictionary consisting of
     ++ entries \axiom{x,y,...,z}.
-- insert: (S,%) -> S		      ++ insert an entry
-- member?: (S,%) -> Boolean		      ++ search for an entry
-- remove!: (S,%,NonNegativeInteger) -> %
--   ++ remove!(x,d,n) destructively changes dictionary d by removing
--   ++ up to n entries y such that \axiom{y = x}.
-- remove!: (S->Boolean,%,NonNegativeInteger) -> %
--   ++ remove!(p,d,n) destructively changes dictionary d by removing
--   ++ up to n entries x such that \axiom{p(x)} is true.
   if % has FiniteAggregate S then
     remove!: (S,%) -> %
       ++ remove!(x,d) destructively changes dictionary d by removing
       ++ all entries y such that \axiom{y = x}.
     remove!: (S->Boolean,%) -> %
       ++ remove!(p,d) destructively changes dictionary d by removeing
       ++ all entries x such that \axiom{p(x)} is true.
     select!: (S->Boolean,%) -> %
       ++ select!(p,d) destructively changes dictionary d by removing
       ++ all entries x such that \axiom{p(x)} is not true.
 add
   construct l == dictionary l
   dictionary() == empty()
   if % has FiniteAggregate S then
     copy d == dictionary members d
     coerce(s:%):OutputForm ==
       prefix("dictionary"@String :: OutputForm,
				      [x::OutputForm for x in members s])

@

\section{category DIAGG Dictionary}

<<category DIAGG Dictionary>>=
import Boolean
import DictionaryOperations
)abbrev category DIAGG Dictionary
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A dictionary is an aggregate in which entries can be inserted,
++ searched for and removed. Duplicates are thrown away on insertion.
++ This category models the usual notion of dictionary which involves
++ large amounts of data where copying is impractical.
++ Principal operations are thus destructive (non-copying) ones.
Dictionary(S:SetCategory): Category ==
 DictionaryOperations S add
   dictionary l ==
     d := dictionary()
     for x in l repeat insert!(x, d)
     d

   if % has FiniteAggregate S then
    -- remove(f:S->Boolean,t:%)  == remove!(f, copy t)
    -- select(f, t)	   == select!(f, copy t)
     select!(f, t)	 == remove!(not f #1, t)

     --extract! d ==
     --	 empty? d => error "empty dictionary"
     --	 remove!(x := first members d, d, 1)
     --	 x

     s = t ==
       eq?(s,t) => true
       #s ~= #t => false
       and/[member?(x, t) for x in members s]

     remove!(f:S->Boolean, t:%) ==
       for m in members t repeat if f m then remove!(m, t)
       t

@

\section{category MDAGG MultiDictionary}

<<category MDAGG MultiDictionary>>=
import NonNegativeInteger
import DictionaryOperations
)abbrev category MDAGG MultiDictionary
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A multi-dictionary is a dictionary which may contain duplicates.
++ As for any dictionary, its size is assumed large so that
++ copying (non-destructive) operations are generally to be avoided.
MultiDictionary(S:SetCategory): Category == DictionaryOperations S with
-- count: (S,%) -> NonNegativeInteger		       ++ multiplicity count
   insert!: (S,%,NonNegativeInteger) -> %
     ++ insert!(x,d,n) destructively inserts n copies of x into dictionary d.
-- remove!: (S,%,NonNegativeInteger) -> %
--   ++ remove!(x,d,n) destructively removes (up to) n copies of x from
--   ++ dictionary d.
   removeDuplicates!: % -> %
     ++ removeDuplicates!(d) destructively removes any duplicate values
     ++ in dictionary d.
   duplicates: % -> List Record(entry:S,count:NonNegativeInteger)
     ++ duplicates(d) returns a list of values which have duplicates in d
--   ++ duplicates(d) returns a list of		     ++ duplicates iterator
-- to become duplicates: % -> Iterator(D,D)

@

\section{category SETAGG SetAggregate}

<<category SETAGG SetAggregate>>=
import SetCategory
import Collection
)abbrev category SETAGG SetAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: 14 Oct, 1993 by RSS
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A set category lists a collection of set-theoretic operations
++ useful for both finite sets and multisets.
++ Note however that finite sets are distinct from multisets.
++ Although the operations defined for set categories are
++ common to both, the relationship between the two cannot
++ be described by inclusion or inheritance.
SetAggregate(S:SetCategory):
  Category == Join(SetCategory, Collection(S)) with
   partiallyOrderedSet
   part?         : (%, %) -> Boolean
     ++ s < t returns true if all elements of set aggregate s are also
     ++ elements of set aggregate t.
   brace       : () -> %
     ++ brace()$D (otherwise written {}$D)
     ++ creates an empty set aggregate of type D.
     ++ This form is considered obsolete. Use \axiomFun{set} instead.
   brace       : List S -> %
     ++ brace([x,y,...,z]) 
     ++ creates a set aggregate containing items x,y,...,z.
     ++ This form is considered obsolete. Use \axiomFun{set} instead.
   set	       : () -> %
     ++ set()$D creates an empty set aggregate of type D.
   set	       : List S -> %
     ++ set([x,y,...,z]) creates a set aggregate containing items x,y,...,z.
   intersect: (%, %) -> %
     ++ intersect(u,v) returns the set aggregate w consisting of
     ++ elements common to both set aggregates u and v.
     ++ Note: equivalent to the notation (not currently supported)
     ++ {x for x in u | member?(x,v)}.
   difference  : (%, %) -> %
     ++ difference(u,v) returns the set aggregate w consisting of
     ++ elements in set aggregate u but not in set aggregate v.
     ++ If u and v have no elements in common, \axiom{difference(u,v)}
     ++ returns a copy of u.
     ++ Note: equivalent to the notation (not currently supported)
     ++ \axiom{{x for x in u | not member?(x,v)}}.
   difference  : (%, S) -> %
     ++ difference(u,x) returns the set aggregate u with element x removed.
     ++ If u does not contain x, a copy of u is returned.
     ++ Note: \axiom{difference(s, x) = difference(s, {x})}.
   symmetricDifference : (%, %) -> %
     ++ symmetricDifference(u,v) returns the set aggregate of elements x which
     ++ are members of set aggregate u or set aggregate v but not both.
     ++ If u and v have no elements in common, \axiom{symmetricDifference(u,v)}
     ++ returns a copy of u.
     ++ Note: \axiom{symmetricDifference(u,v) = union(difference(u,v),difference(v,u))}
   subset?     : (%, %) -> Boolean
     ++ subset?(u,v) tests if u is a subset of v.
     ++ Note: equivalent to
     ++ \axiom{reduce(and,{member?(x,v) for x in u},true,false)}.
   union       : (%, %) -> %
     ++ union(u,v) returns the set aggregate of elements which are members
     ++ of either set aggregate u or v.
   union       : (%, S) -> %
     ++ union(u,x) returns the set aggregate u with the element x added.
     ++ If u already contains x, \axiom{union(u,x)} returns a copy of u.
   union       : (S, %) -> %
     ++ union(x,u) returns the set aggregate u with the element x added.
     ++ If u already contains x, \axiom{union(x,u)} returns a copy of u.
 add
  symmetricDifference(x, y)    == union(difference(x, y), difference(y, x))
  union(s:%, x:S) == union(s, {x})
  union(x:S, s:%) == union(s, {x})
  difference(s:%, x:S) == difference(s, {x})

@

\section{category FSAGG FiniteSetAggregate}

<<category FSAGG FiniteSetAggregate>>=
import Dictionary
import SetAggregate
)abbrev category FSAGG FiniteSetAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: 14 Oct, 1993 by RSS
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A finite-set aggregate models the notion of a finite set, that is,
++ a collection of elements characterized by membership, but not
++ by order or multiplicity.
++ See \spadtype{Set} for an example.
FiniteSetAggregate(S:SetCategory): Category ==
  Join(Dictionary S, SetAggregate S,FiniteAggregate S) with
    cardinality: % -> NonNegativeInteger
      ++ cardinality(u) returns the number of elements of u.
      ++ Note: \axiom{cardinality(u) = #u}.
    if S has Finite then
      Finite
      complement: % -> %
	++ complement(u) returns the complement of the set u,
	++ i.e. the set of all values not in u.
      universe: () -> %
	++ universe()$D returns the universal set for finite set aggregate D.
    if S has OrderedSet then
      max: % -> S
	++ max(u) returns the largest element of aggregate u.
      min: % -> S
	++ min(u) returns the smallest element of aggregate u.

 add
   part?(s,t)	   == #s < #t and s = intersect(s,t)
   s = t	   == #s = #t and empty? difference(s,t)
   brace l	   == construct l
   set	 l	   == construct l
   cardinality s   == #s
   construct l	   == (s := set(); for x in l repeat insert!(x,s); s)
   count(x:S, s:%) == (member?(x, s) => 1; 0)
   subset?(s, t)   == #s < #t and (and/[member?(x, t) for x in members s])

   coerce(s:%):OutputForm ==
     brace [x::OutputForm for x in members s]$List(OutputForm)

   intersect(s, t) ==
     i := {}
     for x in members s | member?(x, t) repeat insert!(x, i)
     i

   difference(s:%, t:%) ==
     m := copy s
     for x in members t repeat remove!(x, m)
     m

   symmetricDifference(s, t) ==
     d := copy s
     for x in members t repeat
       if member?(x, s) then remove!(x, d) else insert!(x, d)
     d

   union(s:%, t:%) ==
      u := copy s
      for x in members t repeat insert!(x, u)
      u

   if S has Finite then
     universe()	  == {index(i::PositiveInteger) for i in 1..size()$S}
     complement s == difference(universe(), s )
     size()	  == 2 ** size()$S
     index i	 == {index(j::PositiveInteger)$S for j in 1..size()$S | bit?(i-1,j-1)}
     random()	  == index((random()$Integer rem (size()$% + 1))::PositiveInteger)

     lookup s ==
       n:PositiveInteger := 1
       for x in members s repeat n := n + 2 ** ((lookup(x) - 1)::NonNegativeInteger)
       n

   if S has OrderedSet then
     max s ==
       l := members s
       empty? l => error "Empty set"
       reduce("max", l)

     min s ==
       l := members s
       empty? l => error "Empty set"
       reduce("min", l)

@

\section{category MSETAGG MultisetAggregate}

<<category MSETAGG MultisetAggregate>>=
import MultiDictionary
import SetAggregate
)abbrev category MSETAGG MultisetAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A multi-set aggregate is a set which keeps track of the multiplicity
++ of its elements.
MultisetAggregate(S:SetCategory):
 Category == Join(MultiDictionary S, SetAggregate S)

@

\section{category OMSAGG OrderedMultisetAggregate}

<<category OMSAGG OrderedMultisetAggregate>>=
import MultisetAggregate
import PriorityQueueAggregate
import List
)abbrev category OMSAGG OrderedMultisetAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ An ordered-multiset aggregate is a multiset built over an ordered set S
++ so that the relative sizes of its entries can be assessed.
++ These aggregates serve as models for priority queues.
OrderedMultisetAggregate(S:OrderedSet): Category ==
   Join(MultisetAggregate S,PriorityQueueAggregate S) with
   -- max: % -> S		      ++ smallest entry in the set
   -- duplicates: % -> List Record(entry:S,count:NonNegativeInteger)
        ++ to become an in order iterator
      min: % -> S
	++ min(u) returns the smallest entry in the multiset aggregate u.

@

\section{category KDAGG KeyedDictionary}

<<category KDAGG KeyedDictionary>>=
import Dictionary
import List
)abbrev category KDAGG KeyedDictionary
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A keyed dictionary is a dictionary of key-entry pairs for which there is
++ a unique entry for each key.
KeyedDictionary(Key:SetCategory, Entry:SetCategory): Category ==
  Join(Dictionary Record(key:Key,entry:Entry),IndexedAggregate(Key,Entry)) with
   key?: (Key, %) -> Boolean
     ++ key?(k,t) tests if k is a key in table t.
   keys: % -> List Key
     ++ keys(t) returns the list the keys in table t.
   -- to become keys: % -> Key* and keys: % -> Iterator(Entry,Entry)
   remove!: (Key, %) -> Union(Entry,"failed")
     ++ remove!(k,t) searches the table t for the key k removing
     ++ (and return) the entry if there.
     ++ If t has no such key, \axiom{remove!(k,t)} returns "failed".
   search: (Key, %) -> Union(Entry,"failed")
     ++ search(k,t) searches the table t for the key k,
     ++ returning the entry stored in t for key k.
     ++ If t has no such key, \axiom{search(k,t)} returns "failed".
 add
   key?(k, t) == search(k, t) case Entry

   member?(p: Record(key: Key,entry: Entry), t: %): Boolean ==
     r := search(p.key, t)
     r case Entry and r::Entry = p.entry

   if % has FiniteAggregate Record(key:Key,entry:Entry) then
     keys t == [x.key for x in members t]

   elt(t, k) ==
      (r := search(k, t)) case Entry => r::Entry
      error "key not in table"

   elt(t, k, e) ==
      (r := search(k, t)) case Entry => r::Entry
      e

@

\section{category ELTAB Eltable}

<<category ELTAB Eltable>>=
import Type
import SetCategory
)abbrev category ELTAB Eltable
++ Author: Michael Monagan; revised by Manuel Bronstein
++ Date Created: August 87 through August 88
++ Date Last Updated: April 25, 2010
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ An eltable over domains \spad{S} and \spad{T} is a structure which
++ can be viewed as a function from \spad{S} to \spad{T}.
++ Examples of eltable structures range from data structures, e.g. those
++ of type \spadtype{List}, to algebraic structures, e.g. \spadtype{Polynomial}.
Eltable(S: Type, T: Type): Category == Type with
  elt : (%, S) -> T
     ++ \spad{elt(u,s)} (also written: \spad{u.s}) returns the value
     ++ of \spad{u} at \spad{s}.
     ++ Error: if \spad{u} is not defined at \spad{s}.

@

\section{category ELTAGG EltableAggregate}

<<category ELTAGG EltableAggregate>>=
import Type
import SetCategory
)abbrev category ELTAGG EltableAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ An eltable aggregate is one which can be viewed as a function.
++ For example, the list \axiom{[1,7,4]} can applied to 0,1, and 2 respectively
++ will return the integers 1,7, and 4; thus this list may be viewed
++ as mapping 0 to 1, 1 to 7 and 2 to 4. In general, an aggregate
++ can map members of a domain {\em Dom} to an image domain {\em Im}.
EltableAggregate(Dom:SetCategory, Im:Type): Category ==
  Eltable(Dom, Im) with
    elt : (%, Dom, Im) -> Im
       ++ elt(u, x, y) applies u to x if x is in the domain of u,
       ++ and returns y otherwise.
       ++ For example, if u is a polynomial in \axiom{x} over the rationals,
       ++ \axiom{elt(u,n,0)} may define the coefficient of \axiom{x}
       ++ to the power n, returning 0 when n is out of range.
    qelt: (%, Dom) -> Im
       ++ qelt(u, x) applies \axiom{u} to \axiom{x} without checking whether
       ++ \axiom{x} is in the domain of \axiom{u}.  If \axiom{x} is not in the
       ++ domain of \axiom{u} a memory-access violation may occur.  If a check
       ++ on whether \axiom{x} is in the domain of \axiom{u} is required, use
       ++ the function \axiom{elt}.
    if % has shallowlyMutable then
       setelt : (%, Dom, Im) -> Im
	   ++ setelt(u,x,y) sets the image of x to be y under u,
	   ++ assuming x is in the domain of u.
	   ++ Error: if x is not in the domain of u.
	   -- this function will soon be renamed as setelt!.
       qsetelt!: (%, Dom, Im) -> Im
	   ++ qsetelt!(u,x,y) sets the image of \axiom{x} to be \axiom{y} under
           ++ \axiom{u}, without checking that \axiom{x} is in the domain of
           ++ \axiom{u}.
           ++ If such a check is required use the function \axiom{setelt}.
 add
  qelt(a, x) == elt(a, x)
  if % has shallowlyMutable then
    qsetelt!(a, x, y) == (a.x := y)

@

\section{category IXAGG IndexedAggregate}

<<category IXAGG IndexedAggregate>>=
import Type
import SetCategory
import HomogeneousAggregate
import EltableAggregate
import List
)abbrev category IXAGG IndexedAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ An indexed aggregate is a many-to-one mapping of indices to entries.
++ For example, a one-dimensional-array is an indexed aggregate where
++ the index is an integer.  Also, a table is an indexed aggregate
++ where the indices and entries may have any type.
IndexedAggregate(Index: SetCategory, Entry: Type): Category ==
  Join(HomogeneousAggregate(Entry), EltableAggregate(Index, Entry)) with
   entries: % -> List Entry
      ++ entries(u) returns a list of all the entries of aggregate u
      ++ in no assumed order.
      -- to become entries: % -> Entry* and entries: % -> Iterator(Entry,Entry)
   index?: (Index,%) -> Boolean
      ++ index?(i,u) tests if i is an index of aggregate u.
   indices: % -> List Index
      ++ indices(u) returns a list of indices of aggregate u in no
      ++ particular order.
      -- to become indices: % -> Index* and indices: % -> Iterator(Index,Index).
-- map: ((Entry,Entry)->Entry,%,%,Entry) -> %
--    ++ exists c = map(f,a,b,x), i:Index where
--    ++    c.i = f(a(i,x),b(i,x)) | index?(i,a) or index?(i,b)
   if Entry has BasicType and % has FiniteAggregate Entry then
      entry?: (Entry,%) -> Boolean
	++ entry?(x,u) tests if x equals \axiom{u . i} for some index i.
   if Index has OrderedSet then
      maxIndex: % -> Index
	++ maxIndex(u) returns the maximum index i of aggregate u.
	++ Note: in general,
	++ \axiom{maxIndex(u) = reduce(max,[i for i in indices u])};
	++ if u is a list, \axiom{maxIndex(u) = #u}.
      minIndex: % -> Index
	++ minIndex(u) returns the minimum index i of aggregate u.
	++ Note: in general,
	++ \axiom{minIndex(a) = reduce(min,[i for i in indices a])};
	++ for lists, \axiom{minIndex(a) = 1}.
      first   : % -> Entry
	++ first(u) returns the first element x of u.
	++ Note: for collections, \axiom{first([x,y,...,z]) = x}.
	++ Error: if u is empty.

   if % has shallowlyMutable then
      fill!: (%,Entry) -> %
	++ fill!(u,x) replaces each entry in aggregate u by x.
	++ The modified u is returned as value.
      swap!: (%,Index,Index) -> Void
	++ swap!(u,i,j) interchanges elements i and j of aggregate u.
	++ No meaningful value is returned.
 add
  elt(a, i, x) == (index?(i, a) => qelt(a, i); x)

  if % has FiniteAggregate Entry then
    entries x == members x
    if Entry has BasicType then
      entry?(x, a) == member?(x, a)

  if Index has OrderedSet then
    maxIndex a == "max"/indices(a)
    minIndex a == "min"/indices(a)
    first a    == a minIndex a

  if % has shallowlyMutable then
    map(f, a) == map!(f, copy a)

    map!(f, a) ==
      for i in indices a repeat qsetelt!(a, i, f qelt(a, i))
      a

    fill!(a, x) ==
      for i in indices a repeat qsetelt!(a, i, x)
      a

    swap!(a, i, j) ==
      t := a.i
      qsetelt!(a, i, a.j)
      qsetelt!(a, j, t)

@

\section{category TBAGG TableAggregate}

<<category TBAGG TableAggregate>>=
import SetCategory
import KeyedDictionary
import IndexedAggregate
import Boolean
import OutputForm
import List
)abbrev category TBAGG TableAggregate
++ Author: Michael Monagan, Stephen Watt; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: May 17, 2013.
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A table aggregate is a model of a table, i.e. a discrete many-to-one
++ mapping from keys to entries.
TableAggregate(Key:SetCategory, Entry:SetCategory): Category ==
  Join(KeyedDictionary(Key,Entry), FiniteAggregate Record(key:Key,entry:Entry))  with
   table: () -> %
     ++ table()$T creates an empty table of type T.
   table: List Record(key:Key,entry:Entry) -> %
     ++ table([x,y,...,z]) creates a table consisting of entries
     ++ \axiom{x,y,...,z}.
   -- to become table: Record(key:Key,entry:Entry)* -> %
   map: ((Entry, Entry) -> Entry, %, %) -> %
     ++ map(fn,t1,t2) creates a new table t from given tables t1 and t2 with
     ++ elements fn(x,y) where x and y are corresponding elements from t1
     ++ and t2 respectively.
 add
   table()	       == empty()
   table l	       == dictionary l
-- empty()	       == dictionary()

   insert!(p, t)      == (t(p.key) := p.entry; t)
   indices t	       == keys t

   coerce(t:%):OutputForm ==
     prefix("table"::OutputForm,
		    [k::OutputForm = (t.k)::OutputForm for k in keys t])

   map!(f: Entry->Entry, t: %) ==
      for k in keys t repeat t.k := f t.k
      t

   map(f:(Entry, Entry) -> Entry, s:%, t:%) ==
      z := table()
      for k in keys s | key?(k, t) repeat z.k := f(s.k, t.k)
      z

-- map(f, s, t, x) ==
--    z := table()
--    for k in keys s repeat z.k := f(s.k, t(k, x))
--    for k in keys t | not key?(k, s) repeat z.k := f(t.k, x)
--    z

   members(t:%):List Record(key:Key,entry:Entry) == [[k, t.k] for k in keys t]
   entries(t:%):List Entry == [t.k for k in keys t]

   s:% = t:% ==
     eq?(s,t) => true
     #s ~= #t => false
     for k in keys s repeat
       (e := search(k, t)) case "failed" or (e::Entry) ~= s.k => 
          return false
     true

   map(f: Record(key:Key,entry:Entry)->Record(key:Key,entry:Entry), t: %): % ==
     z := table()
     for k in keys t repeat
       ke: Record(key:Key,entry:Entry) := f [k, t.k]
       z ke.key := ke.entry
     z
   map!(f: Record(key:Key,entry:Entry)->Record(key:Key,entry:Entry), t: %): % ==
     lke: List Record(key:Key,entry:Entry) := nil()
     for k in keys t repeat
       lke := cons(f [k, remove!(k,t)::Entry], lke)
     for ke in lke repeat
       t ke.key := ke.entry
     t

   inspect(t: %): Record(key:Key,entry:Entry) ==
     ks := keys t
     empty? ks => error "Cannot extract from an empty aggregate"
     [first ks, t first ks]

   find(f: Record(key:Key,entry:Entry)->Boolean, t:%): Union(Record(key:Key,entry:Entry), "failed") ==
     for ke in members(t)@List(Record(key:Key,entry:Entry)) repeat if f ke then return ke
     "failed"

   index?(k: Key, t: %): Boolean ==
     search(k,t) case Entry

   remove!(x:Record(key:Key,entry:Entry), t:%) ==
     if member?(x, t) then remove!(x.key, t)
     t
   extract!(t: %): Record(key:Key,entry:Entry) ==
     k: Record(key:Key,entry:Entry) := inspect t
     remove!(k.key, t)
     k

@

\section{category RCAGG RecursiveAggregate}

<<category RCAGG RecursiveAggregate>>=
import Type
import SetCategory
import List
import Boolean
)abbrev category RCAGG RecursiveAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A recursive aggregate over a type S is a model for a
++ a directed graph containing values of type S.
++ Recursively, a recursive aggregate is a {\em node}
++ consisting of a \spadfun{value} from S and 0 or more \spadfun{children}
++ which are recursive aggregates.
++ A node with no children is called a \spadfun{leaf} node.
++ A recursive aggregate may be cyclic for which some operations as noted
++ may go into an infinite loop.
RecursiveAggregate(S:Type): Category == HomogeneousAggregate(S) with
   children: % -> List %
     ++ children(u) returns a list of the children of aggregate u.
   -- should be % -> %* and also needs children: % -> Iterator(S,S)
   nodes: % -> List %
     ++ nodes(u) returns a list of all of the nodes of aggregate u.
   -- to become % -> %* and also nodes: % -> Iterator(S,S)
   leaf?: % -> Boolean
     ++ leaf?(u) tests if u is a terminal node.
   value: % -> S
     ++ value(u) returns the value of the node u.
   elt: (%,"value") -> S
     ++ elt(u,"value") (also written: \axiom{a. value}) is
     ++ equivalent to \axiom{value(a)}.
   cyclic?: % -> Boolean
     ++ cyclic?(u) tests if u has a cycle.
   leaves: % -> List S
     ++ leaves(t) returns the list of values in obtained by visiting the
     ++ nodes of tree \axiom{t} in left-to-right order.
   distance: (%,%) -> Integer
     ++ distance(u,v) returns the path length (an integer) from node u to v.
   if S has BasicType then
      child?: (%,%) -> Boolean
	++ child?(u,v) tests if node u is a child of node v.
      node?: (%,%) -> Boolean
	++ node?(u,v) tests if node u is contained in node v
	++ (either as a child, a child of a child, etc.).
   if % has ShallowlyMutableAggregate S then
      setchildren!: (%,List %)->%
	++ setchildren!(u,v) replaces the current children of node u
	++ with the members of v in left-to-right order.
      setelt: (%,"value",S) -> S
	++ setelt(a,"value",x) (also written \axiom{a . value := x})
	++ is equivalent to \axiom{setvalue!(a,x)}
      setvalue!: (%,S) -> S
	++ setvalue!(u,x) sets the value of node u to x.
 add
   elt(x,"value") == value x
   if % has ShallowlyMutableAggregate S then
     setelt(x,"value",y) == setvalue!(x,y)
   if S has BasicType then
     child?(x,l) == member?(x,children(l))

@

\section{category BRAGG BinaryRecursiveAggregate}

<<category BRAGG BinaryRecursiveAggregate>>=
import Type
import RecursiveAggregate
)abbrev category BRAGG BinaryRecursiveAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A binary-recursive aggregate has 0, 1 or 2 children and
++ serves as a model for a binary tree or a doubly-linked aggregate structure
BinaryRecursiveAggregate(S:Type):Category == RecursiveAggregate S with
   -- needs preorder, inorder and postorder iterators
   left: % -> %
     ++ left(u) returns the left child.
   elt: (%,"left") -> %
     ++ elt(u,"left") (also written: \axiom{a . left}) is
     ++ equivalent to \axiom{left(a)}.
   right: % -> %
     ++ right(a) returns the right child.
   elt: (%,"right") -> %
     ++ elt(a,"right") (also written: \axiom{a . right})
     ++ is equivalent to \axiom{right(a)}.
   if % has ShallowlyMutableAggregate S then
      setelt: (%,"left",%) -> %
	++ setelt(a,"left",b) (also written \axiom{a . left := b}) is equivalent
	++ to \axiom{setleft!(a,b)}.
      setleft!: (%,%) -> %
	 ++ setleft!(a,b) sets the left child of \axiom{a} to be b.
      setelt: (%,"right",%) -> %
	 ++ setelt(a,"right",b) (also written \axiom{b . right := b})
	 ++ is equivalent to \axiom{setright!(a,b)}.
      setright!: (%,%) -> %
	 ++ setright!(a,x) sets the right child of t to be x.
 add
   cycleMax ==> 1000

   elt(x,"left")  == left x
   elt(x,"right") == right x
   leaf? x == empty? x or empty? left x and empty? right x
   leaves t ==
     empty? t => empty()$List(S)
     leaf? t => [value t]
     concat(leaves left t,leaves right t)
   nodes x ==
     l := empty()$List(%)
     empty? x => l
     concat(nodes left x,concat([x],nodes right x))
   children x ==
     l := empty()$List(%)
     empty? x => l
     empty? left x  => [right x]
     empty? right x => [left x]
     [left x, right x]
   if % has SetAggregate(S) and S has BasicType then
     node?(u,v) ==
       empty? v => false
       u = v => true
       for y in children v repeat node?(u,y) => return true
       false
     x = y ==
       empty?(x) => empty?(y)
       empty?(y) => false
       value x = value y and left x = left y and right x = right y
     if % has FiniteAggregate S then
       member?(x,u) ==
	 empty? u => false
	 x = value u => true
	 member?(x,left u) or member?(x,right u)

   if S has CoercibleTo(OutputForm) then
     coerce(t:%): OutputForm ==
       empty? t =>  bracket(empty()$OutputForm)
       v := value(t):: OutputForm
       empty? left t =>
	 empty? right t => v
	 r := (right t)::OutputForm
	 bracket ["."::OutputForm, v, r]
       l := (left t)::OutputForm
       r :=
	 empty? right t => "."::OutputForm
	 (right t)::OutputForm
       bracket [l, v, r]

   if % has FiniteAggregate S then
     aggCount: (%,NonNegativeInteger) -> NonNegativeInteger
     #x == aggCount(x,0)
     aggCount(x,k) ==
       empty? x => 0
       k := k + 1
       k = cycleMax and cyclic? x => error "cyclic tree"
       for y in children x repeat k := aggCount(y,k)
       k

   isCycle?:  (%, List %) -> Boolean
   eqMember?: (%, List %) -> Boolean
   cyclic? x	 == not empty? x and isCycle?(x,empty()$(List %))
   isCycle?(x,acc) ==
     empty? x => false
     eqMember?(x,acc) => true
     for y in children x | not empty? y repeat
       isCycle?(y,acc) => return true
     false
   eqMember?(y,l) ==
     for x in l repeat eq?(x,y) => return true
     false
   if % has ShallowlyMutableAggregate S then
     setelt(x,"left",b)  == setleft!(x,b)
     setelt(x,"right",b) == setright!(x,b)

@

\section{category DLAGG DoublyLinkedAggregate}

<<category DLAGG DoublyLinkedAggregate>>=
import Type
import RecursiveAggregate
)abbrev category DLAGG DoublyLinkedAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A doubly-linked aggregate serves as a model for a doubly-linked
++ list, that is, a list which can has links to both next and previous
++ nodes and thus can be efficiently traversed in both directions.
DoublyLinkedAggregate(S:Type): Category == RecursiveAggregate S with
   last: % -> S
     ++ last(l) returns the last element of a doubly-linked aggregate l.
     ++ Error: if l is empty.
   head: % -> %
     ++ head(l) returns the first element of a doubly-linked aggregate l.
     ++ Error: if l is empty.
   tail: % -> %
     ++ tail(l) returns the doubly-linked aggregate l starting at
     ++ its second element.
     ++ Error: if l is empty.
   previous: % -> %
     ++ previous(l) returns the doubly-link list beginning with its previous
     ++ element.
     ++ Error: if l has no previous element.
     ++ Note: \axiom{next(previous(l)) = l}.
   next: % -> %
     ++ next(l) returns the doubly-linked aggregate beginning with its next
     ++ element.
     ++ Error: if l has no next element.
     ++ Note: \axiom{next(l) = rest(l)} and \axiom{previous(next(l)) = l}.
   if % has ShallowlyMutableAggregate S then
      concat!: (%,%) -> %
	++ concat!(u,v) destructively concatenates doubly-linked aggregate v to the end of doubly-linked aggregate u.
      setprevious!: (%,%) -> %
	++ setprevious!(u,v) destructively sets the previous node of doubly-linked aggregate u to v, returning v.
      setnext!: (%,%) -> %
	++ setnext!(u,v) destructively sets the next node of doubly-linked aggregate u to v, returning v.

@

\section{category URAGG UnaryRecursiveAggregate}

<<category URAGG UnaryRecursiveAggregate>>=
import Type
import RecursiveAggregate
import NonNegativeInteger
)abbrev category URAGG UnaryRecursiveAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A unary-recursive aggregate is a one where nodes may have either
++ 0 or 1 children.
++ This aggregate models, though not precisely, a linked
++ list possibly with a single cycle.
++ A node with one children models a non-empty list, with the
++ \spadfun{value} of the list designating the head, or \spadfun{first}, of the
++ list, and the child designating the tail, or \spadfun{rest}, of the list.
++ A node with no child then designates the empty list.
++ Since these aggregates are recursive aggregates, they may be cyclic.
UnaryRecursiveAggregate(S:Type): Category == RecursiveAggregate S with
   concat: (%,%) -> %
      ++ concat(u,v) returns an aggregate w consisting of the elements of u
      ++ followed by the elements of v.
      ++ Note: \axiom{v = rest(w,#a)}.
   concat: (S,%) -> %
      ++ concat(x,u) returns aggregate consisting of x followed by
      ++ the elements of u.
      ++ Note: if \axiom{v = concat(x,u)} then \axiom{x = first v}
      ++ and \axiom{u = rest v}.
   first: % -> S
      ++ first(u) returns the first element of u
      ++ (equivalently, the value at the current node).
   elt: (%,"first") -> S
      ++ elt(u,"first") (also written: \axiom{u . first}) is equivalent to first u.
   first: (%,NonNegativeInteger) -> %
      ++ first(u,n) returns a copy of the first n (\axiom{n >= 0}) elements of u.
   rest: % -> %
      ++ rest(u) returns an aggregate consisting of all but the first
      ++ element of u
      ++ (equivalently, the next node of u).
   elt: (%,"rest") -> %
      ++ elt(%,"rest") (also written: \axiom{u.rest}) is
      ++ equivalent to \axiom{rest u}.
   rest: (%,NonNegativeInteger) -> %
      ++ rest(u,n) returns the \axiom{n}th (n >= 0) node of u.
      ++ Note: \axiom{rest(u,0) = u}.
   last: % -> S
      ++ last(u) resturn the last element of u.
      ++ Note: for lists, \axiom{last(u) = u . (maxIndex u) = u . (# u - 1)}.
   elt: (%,"last") -> S
      ++ elt(u,"last") (also written: \axiom{u . last}) is equivalent to last u.
   last: (%,NonNegativeInteger) -> %
      ++ last(u,n) returns a copy of the last n (\axiom{n >= 0}) nodes of u.
      ++ Note: \axiom{last(u,n)} is a list of n elements.
   tail: % -> %
      ++ tail(u) returns the last node of u.
      ++ Note: if u is \axiom{shallowlyMutable},
      ++ \axiom{setrest(tail(u),v) = concat(u,v)}.
   second: % -> S
      ++ second(u) returns the second element of u.
      ++ Note: \axiom{second(u) = first(rest(u))}.
   third: % -> S
      ++ third(u) returns the third element of u.
      ++ Note: \axiom{third(u) = first(rest(rest(u)))}.
   cycleEntry: % -> %
      ++ cycleEntry(u) returns the head of a top-level cycle contained in
      ++ aggregate u, or \axiom{empty()} if none exists.
   cycleLength: % -> NonNegativeInteger
      ++ cycleLength(u) returns the length of a top-level cycle
      ++ contained  in aggregate u, or 0 is u has no such cycle.
   cycleTail: % -> %
      ++ cycleTail(u) returns the last node in the cycle, or
      ++ empty if none exists.
   if % has ShallowlyMutableAggregate S then
      concat!: (%,%) -> %
	++ concat!(u,v) destructively concatenates v to the end of u.
	++ Note: \axiom{concat!(u,v) = setlast!(u,v)}.
      concat!: (%,S) -> %
	++ concat!(u,x) destructively adds element x to the end of u.
	++ Note: \axiom{concat!(a,x) = setlast!(a,[x])}.
      cycleSplit!: % -> %
	++ cycleSplit!(u) splits the aggregate by dropping off the cycle.
	++ The value returned is the cycle entry, or nil if none exists.
	++ For example, if \axiom{w = concat(u,v)} is the cyclic list where v is
	++ the head of the cycle, \axiom{cycleSplit!(w)} will drop v off w thus
	++ destructively changing w to u, and returning v.
      setfirst!: (%,S) -> S
	++ setfirst!(u,x) destructively changes the first element of a to x.
      setelt: (%,"first",S) -> S
	++ setelt(u,"first",x) (also written: \axiom{u.first := x}) is
	++ equivalent to \axiom{setfirst!(u,x)}.
      setrest!: (%,%) -> %
	++ setrest!(u,v) destructively changes the rest of u to v.
      setelt: (%,"rest",%) -> %
	++ setelt(u,"rest",v) (also written: \axiom{u.rest := v}) is equivalent to
	++ \axiom{setrest!(u,v)}.
      setlast!: (%,S) -> S
	++ setlast!(u,x) destructively changes the last element of u to x.
      setelt: (%,"last",S) -> S
	++ setelt(u,"last",x) (also written: \axiom{u.last := b})
	++ is equivalent to \axiom{setlast!(u,v)}.
      split!: (%,Integer) -> %
	 ++ split!(u,n) splits u into two aggregates: \axiom{v = rest(u,n)}
	 ++ and \axiom{w = first(u,n)}, returning \axiom{v}.
	 ++ Note: afterwards \axiom{rest(u,n)} returns \axiom{empty()}.
 add
  cycleMax ==> 1000

  findCycle: % -> %

  elt(x, "first") == first x
  elt(x,  "last") == last x
  elt(x,  "rest") == rest x
  second x	  == first rest x
  third x	  == first rest rest x
  cyclic? x	  == not empty? x and not empty? findCycle x
  last x	  == first tail x

  nodes x ==
    l := empty()$List(%)
    while not empty? x repeat
      l := concat(x, l)
      x := rest x
    reverse! l

  children x ==
    l := empty()$List(%)
    empty? x => l
    concat(rest x,l)

  leaf? x == empty? x

  value x ==
    empty? x => error "value of empty object"
    first x

  if % has FiniteAggregate S then
    #x ==
      k: NonNegativeInteger := 0
      while not empty? x repeat
        k = cycleMax and cyclic? x => error "cyclic list"
        x := rest x
        k := k + 1
      k

  tail x ==
    empty? x => error "empty list"
    y := rest x
    for k in 0.. while not empty? y repeat
      k = cycleMax and cyclic? x => error "cyclic list"
      y := rest(x := y)
    x

  findCycle x ==
    y := rest x
    while not empty? y repeat
      if eq?(x, y) then return x
      x := rest x
      y := rest y
      if empty? y then return y
      if eq?(x, y) then return y
      y := rest y
    y

  cycleTail x ==
    empty?(y := x := cycleEntry x) => x
    z := rest x
    while not eq?(x,z) repeat (y := z; z := rest z)
    y

  cycleEntry x ==
    empty? x => x
    empty?(y := findCycle x) => y
    z := rest y
    l: NonNegativeInteger := 1
    while not eq?(y,z) repeat
      z := rest z
      l := l + 1
    y := x
    for k in 1..l repeat y := rest y
    while not eq?(x,y) repeat (x := rest x; y := rest y)
    x

  cycleLength x ==
    empty? x => 0
    empty?(x := findCycle x) => 0
    y := rest x
    k: NonNegativeInteger := 1
    while not eq?(x,y) repeat
      y := rest y
      k := k + 1
    k

  rest(x, n) ==
    for i in 1..n repeat
      empty? x => error "Index out of range"
      x := rest x
    x

  if % has FiniteAggregate S then
    last(x, n) ==
      n > (m := #x) => error "index out of range"
      copy rest(x, (m - n)::NonNegativeInteger)

  if S has BasicType then
    x = y ==
      eq?(x, y) => true
      for k in 0.. while not empty? x and not empty? y repeat
	k = cycleMax and cyclic? x => error "cyclic list"
	first x ~= first y => return false
	x := rest x
	y := rest y
      empty? x and empty? y

    node?(u, v) ==
      for k in 0.. while not empty? v repeat
	u = v => return true
	k = cycleMax and cyclic? v => error "cyclic list"
	v := rest v
      u=v

  if % has ShallowlyMutableAggregate S then
    setelt(x, "first", a) == setfirst!(x, a)
    setelt(x,  "last", a) == setlast!(x, a)
    setelt(x,  "rest", a) == setrest!(x, a)
    concat(x:%, y:%)	  == concat!(copy x, y)

    setlast!(x, s) ==
      empty? x => error "setlast: empty list"
      setfirst!(tail x, s)
      s

    setchildren!(u,lv) ==
      #lv=1 => setrest!(u, first lv)
      error "wrong number of children specified"

    setvalue!(u,s) == setfirst!(u,s)

    split!(p, n) ==
      n < 1 => error "index out of range"
      p := rest(p, (n - 1)::NonNegativeInteger)
      q := rest p
      setrest!(p, empty())
      q

    cycleSplit! x ==
      empty?(y := cycleEntry x) or eq?(x, y) => y
      z := rest x
      while not eq?(z, y) repeat (x := z; z := rest z)
      setrest!(x, empty())
      y

@

\section{category STAGG StreamAggregate}

<<category STAGG StreamAggregate>>=
import Type
import UnaryRecursiveAggregate
import LinearAggregate
import Boolean
)abbrev category STAGG StreamAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A stream aggregate is a linear aggregate which possibly has an infinite
++ number of elements. A basic domain constructor which builds stream
++ aggregates is \spadtype{Stream}. From streams, a number of infinite
++ structures such power series can be built. A stream aggregate may
++ also be infinite since it may be cyclic.
++ For example, see \spadtype{DecimalExpansion}.
StreamAggregate(S:Type): Category ==
   Join(UnaryRecursiveAggregate S, LinearAggregate S) with
      explicitlyFinite?: % -> Boolean
	++ explicitlyFinite?(s) tests if the stream has a finite
	++ number of elements, and false otherwise.
	++ Note: for many datatypes, \axiom{explicitlyFinite?(s) = not possiblyInfinite?(s)}.
      possiblyInfinite?: % -> Boolean
	++ possiblyInfinite?(s) tests if the stream s could possibly
	++ have an infinite number of elements.
	++ Note: for many datatypes, \axiom{possiblyInfinite?(s) = not explictlyFinite?(s)}.
      less?: (%,NonNegativeInteger) -> Boolean
        ++ less?(u,n) tests if u has less than n elements.
      more?: (%,NonNegativeInteger) -> Boolean
        ++ more?(u,n) tests if u has greater than n elements.
      size?: (%,NonNegativeInteger) -> Boolean
        ++ size?(u,n) tests if u has exactly n elements.
 add
   c2: (%, %) -> S

   explicitlyFinite? x == not cyclic? x
   possiblyInfinite? x == cyclic? x
   first(x, n)	       == construct [c2(x, x := rest x) for i in 1..n]

   c2(x, r) ==
     empty? x => error "Index out of range"
     first x

   elt(x:%, i:Integer) ==
     i := i - minIndex x
     negative? i or empty?(x := rest(x, i::NonNegativeInteger)) =>
       error "index out of range"
     first x

   elt(x:%, i:UniversalSegment(Integer)) ==
     l := lo(i) - minIndex x
     negative? l => error "index out of range"
     not hasHi i => copy(rest(x, l::NonNegativeInteger))
     (h := hi(i) - minIndex x) < l => empty()
     first(rest(x, l::NonNegativeInteger), (h - l + 1)::NonNegativeInteger)

   if % has ShallowlyMutableAggregate S then
     concat(x:%, y:%) == concat!(copy x, y)

     concat l ==
       empty? l => empty()
       concat!(copy first l, concat rest l)

     map!(f, l) ==
       y := l
       while not empty? l repeat
	 setfirst!(l, f first l)
	 l := rest l
       y

     fill!(x, s) ==
       y := x
       while not empty? y repeat (setfirst!(y, s); y := rest y)
       x

     setelt(x:%, i:Integer, s:S) ==
      i := i - minIndex x
      negative? i or empty?(x := rest(x,i::NonNegativeInteger)) =>
        error "index out of range"
      setfirst!(x, s)

     setelt(x:%, i:UniversalSegment(Integer), s:S) ==
      negative?(l := lo(i) - minIndex x) => error "index out of range"
      h := if hasHi i then hi(i) - minIndex x else maxIndex x
      h < l => s
      y := rest(x, l::NonNegativeInteger)
      z := rest(y, (h - l + 1)::NonNegativeInteger)
      while not eq?(y, z) repeat (setfirst!(y, s); y := rest y)
      s

     concat!(x:%, y:%) ==
       empty? x => y
       setrest!(tail x, y)
       x

@

\section{category LNAGG LinearAggregate}

<<category LNAGG LinearAggregate>>=
import Type
import Collection
import IndexedAggregate
import NonNegativeInteger
import Integer
)abbrev category LNAGG LinearAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A linear aggregate is an aggregate whose elements are indexed by integers.
++ Examples of linear aggregates are strings, lists, and
++ arrays.
++ Most of the exported operations for linear aggregates are non-destructive
++ but are not always efficient for a particular aggregate.
++ For example, \spadfun{concat} of two lists needs only to copy its first
++ argument, whereas \spadfun{concat} of two arrays needs to copy both arguments.
++ Most of the operations exported here apply to infinite objects (e.g. streams)
++ as well to finite ones.
++ For finite linear aggregates, see \spadtype{FiniteLinearAggregate}.
LinearAggregate(S:Type): Category ==
  Join(IndexedAggregate(Integer, S), Collection(S),_
    Eltable(UniversalSegment Integer, %)) with
   new	 : (NonNegativeInteger,S) -> %
     ++ new(n,x) returns \axiom{fill!(new n,x)}.
   concat: (%,S) -> %
     ++ concat(u,x) returns aggregate u with additional element x at the end.
     ++ Note: for lists, \axiom{concat(u,x) == concat(u,[x])}
   concat: (S,%) -> %
     ++ concat(x,u) returns aggregate u with additional element at the front.
     ++ Note: for lists: \axiom{concat(x,u) == concat([x],u)}.
   concat: (%,%) -> %
      ++ concat(u,v) returns an aggregate consisting of the elements of u
      ++ followed by the elements of v.
      ++ Note: if \axiom{w = concat(u,v)} then \axiom{w.i = u.i for i in indices u}
      ++ and \axiom{w.(j + maxIndex u) = v.j for j in indices v}.
   concat: List % -> %
      ++ concat(u), where u is a lists of aggregates \axiom{[a,b,...,c]}, returns
      ++ a single aggregate consisting of the elements of \axiom{a}
      ++ followed by those
      ++ of b followed ... by the elements of c.
      ++ Note: \axiom{concat(a,b,...,c) = concat(a,concat(b,...,c))}.
   map: ((S,S)->S,%,%) -> %
     ++ map(f,u,v) returns a new collection w with elements \axiom{z = f(x,y)}
     ++ for corresponding elements x and y from u and v.
     ++ Note: for linear aggregates, \axiom{w.i = f(u.i,v.i)}.
   delete: (%,Integer) -> %
      ++ delete(u,i) returns a copy of u with the \axiom{i}th element deleted.
      ++ Note: for lists, \axiom{delete(a,i) == concat(a(0..i - 1),a(i + 1,..))}.
   delete: (%,UniversalSegment(Integer)) -> %
      ++ delete(u,i..j) returns a copy of u with the \axiom{i}th through
      ++ \axiom{j}th element deleted.
      ++ Note: \axiom{delete(a,i..j) = concat(a(0..i-1),a(j+1..))}.
   insert: (S,%,Integer) -> %
      ++ insert(x,u,i) returns a copy of u having x as its \axiom{i}th element.
      ++ Note: \axiom{insert(x,a,k) = concat(concat(a(0..k-1),x),a(k..))}.
   insert: (%,%,Integer) -> %
      ++ insert(v,u,k) returns a copy of u having v inserted beginning at the
      ++ \axiom{i}th element.
      ++ Note: \axiom{insert(v,u,k) = concat( u(0..k-1), v, u(k..) )}.
   if % has shallowlyMutable then setelt: (%,UniversalSegment(Integer),S) -> S
      ++ setelt(u,i..j,x) (also written: \axiom{u(i..j) := x}) destructively
      ++ replaces each element in the segment \axiom{u(i..j)} by x.
      ++ The value x is returned.
      ++ Note: u is destructively change so
      ++ that \axiom{u.k := x for k in i..j};
      ++ its length remains unchanged.
 add
  indices a	 == [i for i in minIndex a .. maxIndex a]
  index?(i, a)	 == i >= minIndex a and i <= maxIndex a
  concat(a:%, x:S)	== concat(a, new(1, x))
  concat(x:S, y:%)	== concat(new(1, x), y)
  insert(x:S, a:%, i:Integer) == insert(new(1, x), a, i)
  if % has FiniteAggregate S then
    maxIndex l == #l - 1 + minIndex l

--if % has ShallowlyMutableAggregate S then new(n, s)  == fill!(new n, s)

@

\section{category FLAGG FiniteLinearAggregate}

<<category FLAGG FiniteLinearAggregate>>=
import Type
import SetCategory
import OrderedSet
import LinearAggregate
import Boolean
import Integer
)abbrev category FLAGG FiniteLinearAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A finite linear aggregate is a linear aggregate of finite length.
++ The finite property of the aggregate adds several exports to the
++ list of exports from \spadtype{LinearAggregate} such as
++ \spadfun{reverse}, \spadfun{sort}, and so on.
FiniteLinearAggregate(S:Type): Category == Join(LinearAggregate S,FiniteAggregate S) with
   merge: ((S,S)->Boolean,%,%) -> %
      ++ merge(p,a,b) returns an aggregate c which merges \axiom{a} and b.
      ++ The result is produced by examining each element x of \axiom{a} and y
      ++ of b successively. If \axiom{p(x,y)} is true, then x is inserted into
      ++ the result; otherwise y is inserted. If x is chosen, the next element
      ++ of \axiom{a} is examined, and so on. When all the elements of one
      ++ aggregate are examined, the remaining elements of the other
      ++ are appended.
      ++ For example, \axiom{merge(<,[1,3],[2,7,5])} returns \axiom{[1,2,3,7,5]}.
   reverse: % -> %
      ++ reverse(a) returns a copy of \axiom{a} with elements in reverse order.
   sort: ((S,S)->Boolean,%) -> %
      ++ sort(p,a) returns a copy of \axiom{a} sorted using total ordering predicate p.
   sorted?: ((S,S)->Boolean,%) -> Boolean
      ++ sorted?(p,a) tests if \axiom{a} is sorted according to predicate p.
   position: (S->Boolean, %) -> Integer
      ++ position(p,a) returns the index i of the first x in \axiom{a} such that
      ++ \axiom{p(x)} is true, and \axiom{minIndex(a) - 1} if there is no such x.
   if S has BasicType then
      position: (S, %)	-> Integer
	++ position(x,a) returns the index i of the first occurrence of x in a,
	++ and \axiom{minIndex(a) - 1} if there is no such x.
      position: (S,%,Integer) -> Integer
	++ position(x,a,n) returns the index i of the first occurrence of x in
	++ \axiom{a} where \axiom{i >= n}, and \axiom{minIndex(a) - 1} if no such x is found.
   if S has OrderedSet then
      OrderedSet
      merge: (%,%) -> %
	++ merge(u,v) merges u and v in ascending order.
	++ Note: \axiom{merge(u,v) = merge(<=,u,v)}.
      sort: % -> %
	++ sort(u) returns an u with elements in ascending order.
	++ Note: \axiom{sort(u) = sort(<=,u)}.
      sorted?: % -> Boolean
	++ sorted?(u) tests if the elements of u are in ascending order.
   if % has ShallowlyMutableAggregate S then
      copyInto!: (%,%,Integer) -> %
	++ copyInto!(u,v,i) returns aggregate u containing a copy of
	++ v inserted at element i.
      reverse!: % -> %
	++ reverse!(u) returns u with its elements in reverse order.
      sort!: ((S,S)->Boolean,%) -> %
	++ sort!(p,u) returns u with its elements ordered by p.
      if S has OrderedSet then sort!: % -> %
	++ sort!(u) returns u with its elements in ascending order.
 add
    if S has BasicType then
      position(x:S, t:%) == position(x, t, minIndex t)

    if S has OrderedSet then
--    sorted? l	  == sorted?(_<$S, l)
      sorted? l	  == sorted?(#1 < #2 or #1 = #2, l)
      merge(x, y) == merge(_<$S, x, y)
      sort l	  == sort(_<$S, l)

    if % has ShallowlyMutableAggregate S then
      reverse x	 == reverse! copy x
      sort(f, l) == sort!(f, copy l)

      if S has OrderedSet then
	sort! l == sort!(_<$S, l)

@

\section{category A1AGG OneDimensionalArrayAggregate}

<<category A1AGG OneDimensionalArrayAggregate>>=
import Type
import FiniteLinearAggregate
)abbrev category A1AGG OneDimensionalArrayAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ One-dimensional-array aggregates serves as models for one-dimensional arrays.
++ Categorically, these aggregates are finite linear aggregates
++ with the shallowly mutable property, that is, any component of
++ the array may be changed without affecting the
++ identity of the overall array.
++ Array data structures are typically represented by a fixed area in storage and
++ therefore cannot efficiently grow or shrink on demand as can list structures
++ (see however \spadtype{FlexibleArray} for a data structure which
++ is a cross between a list and an array).
++ Iteration over, and access to, elements of arrays is extremely fast
++ (and often can be optimized to open-code).
++ Insertion and deletion however is generally slow since an entirely new
++ data structure must be created for the result.
OneDimensionalArrayAggregate(S:Type): Category ==
    Join(FiniteLinearAggregate S,ShallowlyMutableAggregate S)
  add
    members x	    == [qelt(x, i) for i in minIndex x .. maxIndex x]
    sort!(f, a) == quickSort(f, a)$FiniteLinearAggregateSort(S, %)

    any?(f, a) ==
      for i in minIndex a .. maxIndex a repeat
	f qelt(a, i) => return true
      false

    every?(f, a) ==
      for i in minIndex a .. maxIndex a repeat
	not(f qelt(a, i)) => return false
      true

    position(f:S -> Boolean, a:%) ==
      for i in minIndex a .. maxIndex a repeat
	f qelt(a, i) => return i
      minIndex(a) - 1

    find(f, a) ==
      for i in minIndex a .. maxIndex a repeat
	f qelt(a, i) => return qelt(a, i)
      "failed"

    count(f:S->Boolean, a:%) ==
      n:NonNegativeInteger := 0
      for i in minIndex a .. maxIndex a repeat
	if f(qelt(a, i)) then n := n+1
      n

    map!(f, a) ==
      for i in minIndex a .. maxIndex a repeat
	qsetelt!(a, i, f qelt(a, i))
      a

    setelt(a:%, s:UniversalSegment(Integer), x:S) ==
      l := lo s; h := if hasHi s then hi s else maxIndex a
      l < minIndex a or h > maxIndex a => error "index out of range"
      for k in l..h repeat qsetelt!(a, k, x)
      x

    reduce(f, a) ==
      empty? a => error "cannot reduce an empty aggregate"
      r := qelt(a, m := minIndex a)
      for k in m+1 .. maxIndex a repeat r := f(r, qelt(a, k))
      r

    reduce(f, a, identity) ==
      for k in minIndex a .. maxIndex a repeat
	identity := f(identity, qelt(a, k))
      identity

    if S has BasicType then
       reduce(f, a, identity,absorber) ==
	 for k in minIndex a .. maxIndex a while identity ~= absorber
		repeat identity := f(identity, qelt(a, k))
	 identity

-- this is necessary since new has disappeared.
    stupidnew: (NonNegativeInteger, %, %) -> %
    stupidget: List % -> S
-- a and b are not both empty if n > 0
    stupidnew(n, a, b) ==
      zero? n => empty()
      new(n, (empty? a => qelt(b, minIndex b); qelt(a, minIndex a)))
-- at least one element of l must be non-empty
    stupidget l ==
      for a in l repeat
	not empty? a => return first a
      error "Should not happen"

    map(f, a, b) ==
      m := max(minIndex a, minIndex b)
      n := min(maxIndex a, maxIndex b)
      l := max(0, n - m + 1)::NonNegativeInteger
      c := stupidnew(l, a, b)
      for i in minIndex(c).. for j in m..n repeat
	qsetelt!(c, i, f(qelt(a, j), qelt(b, j)))
      c

--  map(f, a, b, x) ==
--    m := min(minIndex a, minIndex b)
--    n := max(maxIndex a, maxIndex b)
--    l := (n - m + 1)::NonNegativeInteger
--    c := new l
--    for i in minIndex(c).. for j in m..n repeat
--	qsetelt!(c, i, f(a(j, x), b(j, x)))
--    c

    merge(f, a, b) ==
      r := stupidnew(#a + #b, a, b)
      i := minIndex a
      m := maxIndex a
      j := minIndex b
      n := maxIndex b
      k := minIndex(r)
      while i <= m and j <= n repeat
	if f(qelt(a, i), qelt(b, j)) then
	  qsetelt!(r, k, qelt(a, i))
	  i := i+1
	else
	  qsetelt!(r, k, qelt(b, j))
	  j := j+1
        k := k + 1
      while i <= m repeat
        qsetelt!(r, k, elt(a, i))
        k := k + 1
        i := i + 1
      while j <= n repeat
        qsetelt!(r, k, elt(b, j))
        k := k + 1
        j := j + 1
      r

    elt(a:%, s:UniversalSegment(Integer)) ==
      l := lo s
      h := if hasHi s then hi s else maxIndex a
      l < minIndex a or h > maxIndex a => error "index out of range"
      r := stupidnew(max(0, h - l + 1)::NonNegativeInteger, a, a)
      for k in minIndex r.. for i in l..h repeat
	qsetelt!(r, k, qelt(a, i))
      r

    insert(a:%, b:%, i:Integer) ==
      m := minIndex b
      n := maxIndex b
      i < m or i > n => error "index out of range"
      y := stupidnew(#a + #b, a, b)
      k := minIndex y
      for j in m..i-1 repeat
	qsetelt!(y, k, qelt(b, j))
        k := k + 1
      for j in minIndex a .. maxIndex a repeat
	qsetelt!(y, k, qelt(a, j))
        k := k + 1
      for j in i..n repeat
        qsetelt!(y, k, qelt(b, j))
        k := k + 1
      y

    copy x ==
      y := stupidnew(#x, x, x)
      for i in minIndex x .. maxIndex x for j in minIndex y .. repeat
	qsetelt!(y, j, qelt(x, i))
      y

    copyInto!(y, x, s) ==
      s < minIndex y or s + #x > maxIndex y + 1 =>
					      error "index out of range"
      for i in minIndex x .. maxIndex x for j in s.. repeat
	qsetelt!(y, j, qelt(x, i))
      y

    construct l ==
--    a := new(#l)
      empty? l => empty()
      a := new(#l, first l)
      for i in minIndex(a).. for x in l repeat qsetelt!(a, i, x)
      a

    delete(a:%, s:UniversalSegment(Integer)) ==
      l := lo s; h := if hasHi s then hi s else maxIndex a
      l < minIndex a or h > maxIndex a => error "index out of range"
      h < l => copy a
      r := stupidnew((#a - h + l - 1)::NonNegativeInteger, a, a)
      k := minIndex(r)
      for i in minIndex a..l-1 repeat
	qsetelt!(r, k, qelt(a, i))
        k := k + 1
      for i in h+1 .. maxIndex a repeat
	qsetelt!(r, k, qelt(a, i))
        k := k + 1
      r

    delete(x:%, i:Integer) ==
      i < minIndex x or i > maxIndex x => error "index out of range"
      y := stupidnew((#x - 1)::NonNegativeInteger, x, x)
      k := minIndex y
      for j in minIndex x..i-1 repeat
	qsetelt!(y, k, qelt(x, j))
        k := k + 1
      for j in i+1 .. maxIndex x repeat
	qsetelt!(y, k, qelt(x, j))
        k := k + 1
      y

    reverse! x ==
      m := minIndex x
      n := maxIndex x
      for i in 0..((n-m) quo 2) repeat swap!(x, m+i, n-i)
      x

    concat l ==
      empty? l => empty()
      n := +/[#a for a in l]
      i := minIndex(r := new(n, stupidget l))
      for a in l repeat
	copyInto!(r, a, i)
	i := i + #a
      r

    sorted?(f, a) ==
      for i in minIndex(a)..maxIndex(a)-1 repeat
	not f(qelt(a, i), qelt(a, i + 1)) => return false
      true

    concat(x:%, y:%) ==
      z := stupidnew(#x + #y, x, y)
      copyInto!(z, x, i := minIndex z)
      copyInto!(z, y, i + #x)
      z

    if S has CoercibleTo(OutputForm) then
      coerce(r:%):OutputForm ==
	bracket commaSeparate
	      [qelt(r, k)::OutputForm for k in minIndex r .. maxIndex r]

    if S has BasicType then
      x = y ==
	#x ~= #y => false
	for i in minIndex x .. maxIndex x repeat
	  not(qelt(x, i) = qelt(y, i)) => return false
	true

      position(x:S, t:%, s:Integer) ==
	n := maxIndex t
	s < minIndex t or s > n => error "index out of range"
	for k in s..n repeat
	  qelt(t, k) = x => return k
	minIndex(t) - 1

    if S has OrderedSet then
      a < b ==
	for i in minIndex a .. maxIndex a
	  for j in minIndex b .. maxIndex b repeat
	    qelt(a, i) ~= qelt(b, j) => return a.i < b.j
	#a < #b


@

\section{category ELAGG ExtensibleLinearAggregate}

<<category ELAGG ExtensibleLinearAggregate>>=
import Type
import LinearAggregate
import OrderedSet
import Integer
)abbrev category ELAGG ExtensibleLinearAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ An extensible aggregate is one which allows insertion and deletion of entries.
++ These aggregates are models of lists and streams which are represented
++ by linked structures so as to make insertion, deletion, and
++ concatenation efficient. However, access to elements of these
++ extensible aggregates is generally slow since access is made from the end.
++ See \spadtype{FlexibleArray} for an exception.
ExtensibleLinearAggregate(S:Type):Category == Join(LinearAggregate S,ShallowlyMutableAggregate S) with
   concat!: (%,S) -> %
     ++ concat!(u,x) destructively adds element x to the end of u.
   concat!: (%,%) -> %
     ++ concat!(u,v) destructively appends v to the end of u.
     ++ v is unchanged
   delete!: (%,Integer) -> %
     ++ delete!(u,i) destructively deletes the \axiom{i}th element of u.
   delete!: (%,UniversalSegment(Integer)) -> %
     ++ delete!(u,i..j) destructively deletes elements u.i through u.j.
   remove!: (S->Boolean,%) -> %
     ++ remove!(p,u) destructively removes all elements x of
     ++ u such that \axiom{p(x)} is true.
   insert!: (S,%,Integer) -> %
     ++ insert!(x,u,i) destructively inserts x into u at position i.
   insert!: (%,%,Integer) -> %
     ++ insert!(v,u,i) destructively inserts aggregate v into u at position i.
   merge!: ((S,S)->Boolean,%,%) -> %
     ++ merge!(p,u,v) destructively merges u and v using predicate p.
   select!: (S->Boolean,%) -> %
     ++ select!(p,u) destructively changes u by keeping only values x such that
     ++ \axiom{p(x)}.
   if S has BasicType then
     remove!: (S,%) -> %
       ++ remove!(x,u) destructively removes all values x from u.
     removeDuplicates!: % -> %
       ++ removeDuplicates!(u) destructively removes duplicates from u.
   if S has OrderedSet then merge!: (%,%) -> %
       ++ merge!(u,v) destructively merges u and v in ascending order.
 add
   delete(x:%, i:Integer)	   == delete!(copy x, i)
   delete(x:%, i:UniversalSegment(Integer))	   == delete!(copy x, i)
   remove(f:S -> Boolean, x:%)   == remove!(f, copy x)
   insert(s:S, x:%, i:Integer)   == insert!(s, copy x, i)
   insert(w:%, x:%, i:Integer)   == insert!(copy w, copy x, i)
   select(f, x)		   == select!(f, copy x)
   concat(x:%, y:%)	   == concat!(copy x, y)
   concat(x:%, y:S)	   == concat!(copy x, new(1, y))
   concat!(x:%, y:S)	   == concat!(x, new(1, y))
   if S has BasicType then
     remove(s:S, x:%)	     == remove!(s, copy x)
     remove!(s:S, x:%)	     == remove!(#1 = s, x)
     removeDuplicates(x:%)   == removeDuplicates!(copy x)

   if S has OrderedSet then
     merge!(x, y) == merge!(_<$S, x, y)

@

\section{category LSAGG ListAggregate}

<<category LSAGG ListAggregate>>=
import Type
import StreamAggregate
import FiniteLinearAggregate
import ExtensibleLinearAggregate
)abbrev category LSAGG ListAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A list aggregate is a model for a linked list data structure.
++ A linked list is a versatile
++ data structure. Insertion and deletion are efficient and
++ searching is a linear operation.
ListAggregate(S:Type): Category == Join(StreamAggregate S,
   FiniteLinearAggregate S, ExtensibleLinearAggregate S) with
      list: S -> %
	++ list(x) returns the list of one element x.
 add
   cycleMax ==> 1000

   mergeSort: ((S, S) -> Boolean, %, Integer) -> %

   sort!(f, l)	      == mergeSort(f, l, #l)
   list x		   == concat(x, empty())
   reduce(f, x)		   ==
     empty? x => error "reducing over an empty list needs the 3 argument form"
     reduce(f, rest x, first x)
   merge(f, p, q)	   == merge!(f, copy p, copy q)

   select!(f, x) ==
     while not empty? x and not f first x repeat x := rest x
     empty? x => x
     y := x
     z := rest y
     while not empty? z repeat
       if f first z then (y := z; z := rest z)
		    else (z := rest z; setrest!(y, z))
     x

   merge!(f, p, q) ==
     empty? p => q
     empty? q => p
     eq?(p, q) => error "cannot merge a list into itself"
     r: %
     t: %
     if f(first p, first q)
       then (r := t := p; p := rest p)
       else (r := t := q; q := rest q)
     while not empty? p and not empty? q repeat
       if f(first p, first q)
	 then (setrest!(t, p); t := p; p := rest p)
	 else (setrest!(t, q); t := q; q := rest q)
     setrest!(t, if empty? p then q else p)
     r

   insert!(s:S, x:%, i:Integer) ==
     i < (m := minIndex x) => error "index out of range"
     i = m => concat(s, x)
     y := rest(x, (i - 1 - m)::NonNegativeInteger)
     z := rest y
     setrest!(y, concat(s, z))
     x

   insert!(w:%, x:%, i:Integer) ==
     i < (m := minIndex x) => error "index out of range"
     i = m => concat!(w, x)
     y := rest(x, (i - 1 - m)::NonNegativeInteger)
     z := rest y
     setrest!(y, w)
     concat!(y, z)
     x

   remove!(f:S -> Boolean, x:%) ==
     while not empty? x and f first x repeat x := rest x
     empty? x => x
     p := x
     q := rest x
     while not empty? q repeat
       if f first q then q := setrest!(p, rest q)
		    else (p := q; q := rest q)
     x

   delete!(x:%, i:Integer) ==
     i < (m := minIndex x) => error "index out of range"
     i = m => rest x
     y := rest(x, (i - 1 - m)::NonNegativeInteger)
     setrest!(y, rest(y, 2))
     x

   delete!(x:%, i:UniversalSegment(Integer)) ==
     (l := lo i) < (m := minIndex x) => error "index out of range"
     h := if hasHi i then hi i else maxIndex x
     h < l => x
     l = m => rest(x, (h + 1 - m)::NonNegativeInteger)
     t := rest(x, (l - 1 - m)::NonNegativeInteger)
     setrest!(t, rest(t, (h - l + 2)::NonNegativeInteger))
     x

   find(f, x) ==
     while not empty? x and not f first x repeat x := rest x
     empty? x => "failed"
     first x

   position(f:S -> Boolean, x:%) ==
     k := minIndex(x)
     while not empty? x and not f first x repeat
       x := rest x
       k := k + 1
     empty? x => minIndex(x) - 1
     k

   mergeSort(f, p, n) ==
     if n = 2 and f(first rest p, first p) then p := reverse! p
     n < 3 => p
     l := (n quo 2)::NonNegativeInteger
     q := split!(p, l)
     p := mergeSort(f, p, l)
     q := mergeSort(f, q, n - l)
     merge!(f, p, q)

   sorted?(f, l) ==
     empty? l => true
     p := rest l
     while not empty? p repeat
       not f(first l, first p) => return false
       p := rest(l := p)
     true

   reduce(f, x, i) ==
     r := i
     while not empty? x repeat (r := f(r, first x); x := rest x)
     r

   if S has BasicType then
      reduce(f, x, i,a) ==
	r := i
	while not empty? x and r ~= a repeat
	  r := f(r, first x)
	  x := rest x
	r

   new(n, s) ==
     l := empty()
     for k in 1..n repeat l := concat(s, l)
     l

   map(f, x, y) ==
     z := empty()
     while not empty? x and not empty? y repeat
       z := concat(f(first x, first y), z)
       x := rest x
       y := rest y
     reverse! z

-- map(f, x, y, d) ==
--   z := empty()
--   while not empty? x and not empty? y repeat
--     z := concat(f(first x, first y), z)
--     x := rest x
--     y := rest y
--   z := reverseInPlace z
--   if not empty? x then
--	z := concat!(z, map(f(#1, d), x))
--   if not empty? y then
--	z := concat!(z, map(f(d, #1), y))
--   z

   reverse! x ==
     empty? x => x
     empty?(y := rest x) => x
     setrest!(x, empty())
     while not empty? y repeat
       z := rest y
       setrest!(y, x)
       x := y
       y := z
     x

   copy x ==
     y := empty()
     for k in 0.. while not empty? x repeat
       k = cycleMax and cyclic? x => error "cyclic list"
       y := concat(first x, y)
       x := rest x
     reverse! y

   copyInto!(y, x, s) ==
     s < (m := minIndex y) => error "index out of range"
     z := rest(y, (s - m)::NonNegativeInteger)
     while not empty? z and not empty? x repeat
       setfirst!(z, first x)
       x := rest x
       z := rest z
     y

   if S has BasicType then
     position(w, x, s) ==
       s < (m := minIndex x) => error "index out of range"
       x := rest(x, (s - m)::NonNegativeInteger)
       k := s
       while not empty? x and w ~= first x repeat
	 x := rest x
         k := k + 1
       empty? x => minIndex x - 1
       k

     removeDuplicates! l ==
       p := l
       while not empty? p repeat
	 p := setrest!(p, remove!(#1 = first p, rest p))
       l

   if S has OrderedSet then
     x < y ==
	while not empty? x and not empty? y repeat
	  first x ~= first y => return(first x < first y)
	  x := rest x
	  y := rest y
	empty? x => not empty? y
	false

@

\section{category ALAGG AssociationListAggregate}

<<category ALAGG AssociationListAggregate>>=
import SetCategory
import TableAggregate
import ListAggregate
)abbrev category ALAGG AssociationListAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ An association list is a list of key entry pairs which may be viewed
++ as a table.	It is a poor mans version of a table:
++ searching for a key is a linear operation.
AssociationListAggregate(Key:SetCategory,Entry:SetCategory): Category ==
   Join(TableAggregate(Key, Entry), ListAggregate Record(key:Key,entry:Entry)) with
      assoc: (Key, %) -> Maybe Record(key:Key,entry:Entry)
	++ assoc(k,u) returns the element x in association list u stored
	++ with key k, or \spad{nothing} if u has no key k.

@

\section{category SRAGG StringAggregate}

<<category SRAGG StringAggregate>>=
import OneDimensionalArrayAggregate Character
import UniversalSegment
import Boolean
import Character
import CharacterClass
import Integer
)abbrev category SRAGG StringAggregate
++ Author: Stephen Watt and Michael Monagan. revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ A string aggregate is a category for strings, that is,
++ one dimensional arrays of characters.
StringAggregate: Category == OneDimensionalArrayAggregate Character with
    lowerCase	    : % -> %
      ++ lowerCase(s) returns the string with all characters in lower case.
    lowerCase!: % -> %
      ++ lowerCase!(s) destructively replaces the alphabetic characters
      ++ in s by lower case.
    upperCase	    : % -> %
      ++ upperCase(s) returns the string with all characters in upper case.
    upperCase!: % -> %
      ++ upperCase!(s) destructively replaces the alphabetic characters
      ++ in s by upper case characters.
    prefix?	    : (%, %) -> Boolean
      ++ prefix?(s,t) tests if the string s is the initial substring of t.
      ++ Note: \axiom{prefix?(s,t) == reduce(and,[s.i = t.i for i in 0..maxIndex s])}.
    suffix?	    : (%, %) -> Boolean
      ++ suffix?(s,t) tests if the string s is the final substring of t.
      ++ Note: \axiom{suffix?(s,t) == reduce(and,[s.i = t.(n - m + i) for i in 0..maxIndex s])}
      ++ where m and n denote the maxIndex of s and t respectively.
    substring?: (%, %, Integer) -> Boolean
      ++ substring?(s,t,i) tests if s is a substring of t beginning at
      ++ index i.
      ++ Note: \axiom{substring?(s,t,0) = prefix?(s,t)}.
    match: (%, %, Character) -> NonNegativeInteger
      ++ match(p,s,wc) tests if pattern \axiom{p} matches subject \axiom{s}
      ++ where \axiom{wc} is a wild card character. If no match occurs,
      ++ the index \axiom{0} is returned; otheriwse, the value returned
      ++ is the first index of the first character in the subject matching
      ++ the subject (excluding that matched by an initial wild-card).
      ++ For example, \axiom{match("*to*","yorktown","*")} returns \axiom{5}
      ++ indicating a successful match starting at index \axiom{5} of
      ++ \axiom{"yorktown"}.
    match?: (%, %, Character) -> Boolean
      ++ match?(s,t,c) tests if s matches t except perhaps for
      ++ multiple and consecutive occurrences of character c.
      ++ Typically c is the blank character.
    replace	    : (%, UniversalSegment(Integer), %) -> %
      ++ replace(s,i..j,t) replaces the substring \axiom{s(i..j)} of s by string t.
    position	    : (%, %, Integer) -> Integer
      ++ position(s,t,i) returns the position j of the substring s in string t,
      ++ where \axiom{j >= i} is required.
    position	    : (CharacterClass, %, Integer) -> Integer
      ++ position(cc,t,i) returns the position \axiom{j >= i} in t of
      ++ the first character belonging to cc.
    coerce	    : Character -> %
      ++ coerce(c) returns c as a string s with the character c.

    split: (%, Character) -> List %
      ++ split(s,c) returns a list of substrings delimited by character c.
    split: (%, CharacterClass) -> List %
      ++ split(s,cc) returns a list of substrings delimited by characters in cc.

    trim: (%, Character) -> %
      ++ trim(s,c) returns s with all characters c deleted from right
      ++ and left ends.
      ++ For example, \axiom{trim(" abc ", char " ")} returns \axiom{"abc"}.
    trim: (%, CharacterClass) -> %
      ++ trim(s,cc) returns s with all characters in cc deleted from right
      ++ and left ends.
      ++ For example, \axiom{trim("(abc)", charClass "()")} returns \axiom{"abc"}.
    leftTrim: (%, Character) -> %
      ++ leftTrim(s,c) returns s with all leading characters c deleted.
      ++ For example, \axiom{leftTrim("  abc  ", char " ")} returns \axiom{"abc  "}.
    leftTrim: (%, CharacterClass) -> %
      ++ leftTrim(s,cc) returns s with all leading characters in cc deleted.
      ++ For example, \axiom{leftTrim("(abc)", charClass "()")} returns \axiom{"abc)"}.
    rightTrim: (%, Character) -> %
      ++ rightTrim(s,c) returns s with all trailing occurrences of c deleted.
      ++ For example, \axiom{rightTrim("  abc  ", char " ")} returns \axiom{"  abc"}.
    rightTrim: (%, CharacterClass) -> %
      ++ rightTrim(s,cc) returns s with all trailing occurences of
      ++ characters in cc deleted.
      ++ For example, \axiom{rightTrim("(abc)", charClass "()")} returns \axiom{"(abc"}.
    elt: (%, %) -> %
      ++ elt(s,t) returns the concatenation of s and t. It is provided to
      ++ allow juxtaposition of strings to work as concatenation.
      ++ For example, \axiom{"smoo" "shed"} returns \axiom{"smooshed"}.
 add
   trim(s: %, c:  Character)	  == leftTrim(rightTrim(s, c),	c)
   trim(s: %, cc: CharacterClass) == leftTrim(rightTrim(s, cc), cc)

   lowerCase s		 == lowerCase! copy s
   upperCase s		 == upperCase! copy s
   prefix?(s, t)	 == substring?(s, t, minIndex t)
   coerce(c:Character):% == new(1, c)
   elt(s:%, t:%): %	 == concat(s,t)$%

@

\section{category BTAGG BitAggregate}

<<category BTAGG BitAggregate>>=
import OrderedSet
import Logic
import OneDimensionalArrayAggregate Boolean
)abbrev category BTAGG BitAggregate
++ Author: Michael Monagan; revised by Manuel Bronstein and Richard Jenks
++ Date Created: August 87 through August 88
++ Date Last Updated: April 1991
++ Basic Operations:
++ Related Constructors:
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ The bit aggregate category models aggregates representing large
++ quantities of Boolean data.
BitAggregate(): Category ==
  Join(OrderedSet, BooleanLogic, Logic, OneDimensionalArrayAggregate Boolean) with
    nand : (%, %) -> %
      ++ nand(a,b) returns the logical {\em nand} of bit aggregates \axiom{a}
      ++ and \axiom{b}.
    nor	 : (%, %) -> %
      ++ nor(a,b) returns the logical {\em nor} of bit aggregates \axiom{a} and 
      ++ \axiom{b}.
    xor	 : (%, %) -> %
      ++ xor(a,b) returns the logical {\em exclusive-or} of bit aggregates
      ++ \axiom{a} and \axiom{b}.

 add
   not v      == map(_not, v)
   ~ v        == map(_~, v)
   v /\ u     == map(_/_\, v, u)
   v \/ u     == map(_\_/, v, u)
   nand(v, u) == map(nand, v, u)
   nor(v, u)  == map(nor, v, u)

@

\section{License}

<<license>>=
--Copyright (c) 1991-2002, The Numerical ALgorithms Group Ltd.
--All rights reserved.
--Copyright (C) 2007-2010, Gabriel Dos Reis.
--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.
--
--    - Neither the name of The Numerical ALgorithms Group Ltd. nor the
--      names of its contributors may 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.
@
<<*>>=
<<license>>

<<category AGG Aggregate>>
<<category HOAGG HomogeneousAggregate>>
<<category SMAGG ShallowlyMutableAggregate>>
<<category FINAGG FiniteAggregate>>
<<category CLAGG Collection>>
<<category BGAGG BagAggregate>>
<<category SKAGG StackAggregate>>
<<category QUAGG QueueAggregate>>
<<category DQAGG DequeueAggregate>>
<<category PRQAGG PriorityQueueAggregate>>
<<category DIOPS DictionaryOperations>>
<<category DIAGG Dictionary>>
<<category MDAGG MultiDictionary>>
<<category SETAGG SetAggregate>>
<<category FSAGG FiniteSetAggregate>>
<<category MSETAGG MultisetAggregate>>
<<category OMSAGG OrderedMultisetAggregate>>
<<category KDAGG KeyedDictionary>>
<<category ELTAB Eltable>>
<<category ELTAGG EltableAggregate>>
<<category IXAGG IndexedAggregate>>
<<category TBAGG TableAggregate>>
<<category RCAGG RecursiveAggregate>>
<<category BRAGG BinaryRecursiveAggregate>>
<<category DLAGG DoublyLinkedAggregate>>
<<category URAGG UnaryRecursiveAggregate>>
<<category STAGG StreamAggregate>>
<<category LNAGG LinearAggregate>>
<<category FLAGG FiniteLinearAggregate>>
<<category A1AGG OneDimensionalArrayAggregate>>
<<category ELAGG ExtensibleLinearAggregate>>
<<category LSAGG ListAggregate>>
<<category ALAGG AssociationListAggregate>>
<<category SRAGG StringAggregate>>
<<category BTAGG BitAggregate>>

@
\eject
\begin{thebibliography}{99}
\bibitem{1} nothing
\end{thebibliography}
\end{document}