summaryrefslogtreecommitdiff
path: root/Build/source/texk/web2c/luatexdir/luatex.web
blob: 9186d5a0e92fdca1c678edcd044fba6be663e5e4 (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
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
5142
5143
5144
5145
5146
5147
5148
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
5231
5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
5341
5342
5343
5344
5345
5346
5347
5348
5349
5350
5351
5352
5353
5354
5355
5356
5357
5358
5359
5360
5361
5362
5363
5364
5365
5366
5367
5368
5369
5370
5371
5372
5373
5374
5375
5376
5377
5378
5379
5380
5381
5382
5383
5384
5385
5386
5387
5388
5389
5390
5391
5392
5393
5394
5395
5396
5397
5398
5399
5400
5401
5402
5403
5404
5405
5406
5407
5408
5409
5410
5411
5412
5413
5414
5415
5416
5417
5418
5419
5420
5421
5422
5423
5424
5425
5426
5427
5428
5429
5430
5431
5432
5433
5434
5435
5436
5437
5438
5439
5440
5441
5442
5443
5444
5445
5446
5447
5448
5449
5450
5451
5452
5453
5454
5455
5456
5457
5458
5459
5460
5461
5462
5463
5464
5465
5466
5467
5468
5469
5470
5471
5472
5473
5474
5475
5476
5477
5478
5479
5480
5481
5482
5483
5484
5485
5486
5487
5488
5489
5490
5491
5492
5493
5494
5495
5496
5497
5498
5499
5500
5501
5502
5503
5504
5505
5506
5507
5508
5509
5510
5511
5512
5513
5514
5515
5516
5517
5518
5519
5520
5521
5522
5523
5524
5525
5526
5527
5528
5529
5530
5531
5532
5533
5534
5535
5536
5537
5538
5539
5540
5541
5542
5543
5544
5545
5546
5547
5548
5549
5550
5551
5552
5553
5554
5555
5556
5557
5558
5559
5560
5561
5562
5563
5564
5565
5566
5567
5568
5569
5570
5571
5572
5573
5574
5575
5576
5577
5578
5579
5580
5581
5582
5583
5584
5585
5586
5587
5588
5589
5590
5591
5592
5593
5594
5595
5596
5597
5598
5599
5600
5601
5602
5603
5604
5605
5606
5607
5608
5609
5610
5611
5612
5613
5614
5615
5616
5617
5618
5619
5620
5621
5622
5623
5624
5625
5626
5627
5628
5629
5630
5631
5632
5633
5634
5635
5636
5637
5638
5639
5640
5641
5642
5643
5644
5645
5646
5647
5648
5649
5650
5651
5652
5653
5654
5655
5656
5657
5658
5659
5660
5661
5662
5663
5664
5665
5666
5667
5668
5669
5670
5671
5672
5673
5674
5675
5676
5677
5678
5679
5680
5681
5682
5683
5684
5685
5686
5687
5688
5689
5690
5691
5692
5693
5694
5695
5696
5697
5698
5699
5700
5701
5702
5703
5704
5705
5706
5707
5708
5709
5710
5711
5712
5713
5714
5715
5716
5717
5718
5719
5720
5721
5722
5723
5724
5725
5726
5727
5728
5729
5730
5731
5732
5733
5734
5735
5736
5737
5738
5739
5740
5741
5742
5743
5744
5745
5746
5747
5748
5749
5750
5751
5752
5753
5754
5755
5756
5757
5758
5759
5760
5761
5762
5763
5764
5765
5766
5767
5768
5769
5770
5771
5772
5773
5774
5775
5776
5777
5778
5779
5780
5781
5782
5783
5784
5785
5786
5787
5788
5789
5790
5791
5792
5793
5794
5795
5796
5797
5798
5799
5800
5801
5802
5803
5804
5805
5806
5807
5808
5809
5810
5811
5812
5813
5814
5815
5816
5817
5818
5819
5820
5821
5822
5823
5824
5825
5826
5827
5828
5829
5830
5831
5832
5833
5834
5835
5836
5837
5838
5839
5840
5841
5842
5843
5844
5845
5846
5847
5848
5849
5850
5851
5852
5853
5854
5855
5856
5857
5858
5859
5860
5861
5862
5863
5864
5865
5866
5867
5868
5869
5870
5871
5872
5873
5874
5875
5876
5877
5878
5879
5880
5881
5882
5883
5884
5885
5886
5887
5888
5889
5890
5891
5892
5893
5894
5895
5896
5897
5898
5899
5900
5901
5902
5903
5904
5905
5906
5907
5908
5909
5910
5911
5912
5913
5914
5915
5916
5917
5918
5919
5920
5921
5922
5923
5924
5925
5926
5927
5928
5929
5930
5931
5932
5933
5934
5935
5936
5937
5938
5939
5940
5941
5942
5943
5944
5945
5946
5947
5948
5949
5950
5951
5952
5953
5954
5955
5956
5957
5958
5959
5960
5961
5962
5963
5964
5965
5966
5967
5968
5969
5970
5971
5972
5973
5974
5975
5976
5977
5978
5979
5980
5981
5982
5983
5984
5985
5986
5987
5988
5989
5990
5991
5992
5993
5994
5995
5996
5997
5998
5999
6000
6001
6002
6003
6004
6005
6006
6007
6008
6009
6010
6011
6012
6013
6014
6015
6016
6017
6018
6019
6020
6021
6022
6023
6024
6025
6026
6027
6028
6029
6030
6031
6032
6033
6034
6035
6036
6037
6038
6039
6040
6041
6042
6043
6044
6045
6046
6047
6048
6049
6050
6051
6052
6053
6054
6055
6056
6057
6058
6059
6060
6061
6062
6063
6064
6065
6066
6067
6068
6069
6070
6071
6072
6073
6074
6075
6076
6077
6078
6079
6080
6081
6082
6083
6084
6085
6086
6087
6088
6089
6090
6091
6092
6093
6094
6095
6096
6097
6098
6099
6100
6101
6102
6103
6104
6105
6106
6107
6108
6109
6110
6111
6112
6113
6114
6115
6116
6117
6118
6119
6120
6121
6122
6123
6124
6125
6126
6127
6128
6129
6130
6131
6132
6133
6134
6135
6136
6137
6138
6139
6140
6141
6142
6143
6144
6145
6146
6147
6148
6149
6150
6151
6152
6153
6154
6155
6156
6157
6158
6159
6160
6161
6162
6163
6164
6165
6166
6167
6168
6169
6170
6171
6172
6173
6174
6175
6176
6177
6178
6179
6180
6181
6182
6183
6184
6185
6186
6187
6188
6189
6190
6191
6192
6193
6194
6195
6196
6197
6198
6199
6200
6201
6202
6203
6204
6205
6206
6207
6208
6209
6210
6211
6212
6213
6214
6215
6216
6217
6218
6219
6220
6221
6222
6223
6224
6225
6226
6227
6228
6229
6230
6231
6232
6233
6234
6235
6236
6237
6238
6239
6240
6241
6242
6243
6244
6245
6246
6247
6248
6249
6250
6251
6252
6253
6254
6255
6256
6257
6258
6259
6260
6261
6262
6263
6264
6265
6266
6267
6268
6269
6270
6271
6272
6273
6274
6275
6276
6277
6278
6279
6280
6281
6282
6283
6284
6285
6286
6287
6288
6289
6290
6291
6292
6293
6294
6295
6296
6297
6298
6299
6300
6301
6302
6303
6304
6305
6306
6307
6308
6309
6310
6311
6312
6313
6314
6315
6316
6317
6318
6319
6320
6321
6322
6323
6324
6325
6326
6327
6328
6329
6330
6331
6332
6333
6334
6335
6336
6337
6338
6339
6340
6341
6342
6343
6344
6345
6346
6347
6348
6349
6350
6351
6352
6353
6354
6355
6356
6357
6358
6359
6360
6361
6362
6363
6364
6365
6366
6367
6368
6369
6370
6371
6372
6373
6374
6375
6376
6377
6378
6379
6380
6381
6382
6383
6384
6385
6386
6387
6388
6389
6390
6391
6392
6393
6394
6395
6396
6397
6398
6399
6400
6401
6402
6403
6404
6405
6406
6407
6408
6409
6410
6411
6412
6413
6414
6415
6416
6417
6418
6419
6420
6421
6422
6423
6424
6425
6426
6427
6428
6429
6430
6431
6432
6433
6434
6435
6436
6437
6438
6439
6440
6441
6442
6443
6444
6445
6446
6447
6448
6449
6450
6451
6452
6453
6454
6455
6456
6457
6458
6459
6460
6461
6462
6463
6464
6465
6466
6467
6468
6469
6470
6471
6472
6473
6474
6475
6476
6477
6478
6479
6480
6481
6482
6483
6484
6485
6486
6487
6488
6489
6490
6491
6492
6493
6494
6495
6496
6497
6498
6499
6500
6501
6502
6503
6504
6505
6506
6507
6508
6509
6510
6511
6512
6513
6514
6515
6516
6517
6518
6519
6520
6521
6522
6523
6524
6525
6526
6527
6528
6529
6530
6531
6532
6533
6534
6535
6536
6537
6538
6539
6540
6541
6542
6543
6544
6545
6546
6547
6548
6549
6550
6551
6552
6553
6554
6555
6556
6557
6558
6559
6560
6561
6562
6563
6564
6565
6566
6567
6568
6569
6570
6571
6572
6573
6574
6575
6576
6577
6578
6579
6580
6581
6582
6583
6584
6585
6586
6587
6588
6589
6590
6591
6592
6593
6594
6595
6596
6597
6598
6599
6600
6601
6602
6603
6604
6605
6606
6607
6608
6609
6610
6611
6612
6613
6614
6615
6616
6617
6618
6619
6620
6621
6622
6623
6624
6625
6626
6627
6628
6629
6630
6631
6632
6633
6634
6635
6636
6637
6638
6639
6640
6641
6642
6643
6644
6645
6646
6647
6648
6649
6650
6651
6652
6653
6654
6655
6656
6657
6658
6659
6660
6661
6662
6663
6664
6665
6666
6667
6668
6669
6670
6671
6672
6673
6674
6675
6676
6677
6678
6679
6680
6681
6682
6683
6684
6685
6686
6687
6688
6689
6690
6691
6692
6693
6694
6695
6696
6697
6698
6699
6700
6701
6702
6703
6704
6705
6706
6707
6708
6709
6710
6711
6712
6713
6714
6715
6716
6717
6718
6719
6720
6721
6722
6723
6724
6725
6726
6727
6728
6729
6730
6731
6732
6733
6734
6735
6736
6737
6738
6739
6740
6741
6742
6743
6744
6745
6746
6747
6748
6749
6750
6751
6752
6753
6754
6755
6756
6757
6758
6759
6760
6761
6762
6763
6764
6765
6766
6767
6768
6769
6770
6771
6772
6773
6774
6775
6776
6777
6778
6779
6780
6781
6782
6783
6784
6785
6786
6787
6788
6789
6790
6791
6792
6793
6794
6795
6796
6797
6798
6799
6800
6801
6802
6803
6804
6805
6806
6807
6808
6809
6810
6811
6812
6813
6814
6815
6816
6817
6818
6819
6820
6821
6822
6823
6824
6825
6826
6827
6828
6829
6830
6831
6832
6833
6834
6835
6836
6837
6838
6839
6840
6841
6842
6843
6844
6845
6846
6847
6848
6849
6850
6851
6852
6853
6854
6855
6856
6857
6858
6859
6860
6861
6862
6863
6864
6865
6866
6867
6868
6869
6870
6871
6872
6873
6874
6875
6876
6877
6878
6879
6880
6881
6882
6883
6884
6885
6886
6887
6888
6889
6890
6891
6892
6893
6894
6895
6896
6897
6898
6899
6900
6901
6902
6903
6904
6905
6906
6907
6908
6909
6910
6911
6912
6913
6914
6915
6916
6917
6918
6919
6920
6921
6922
6923
6924
6925
6926
6927
6928
6929
6930
6931
6932
6933
6934
6935
6936
6937
6938
6939
6940
6941
6942
6943
6944
6945
6946
6947
6948
6949
6950
6951
6952
6953
6954
6955
6956
6957
6958
6959
6960
6961
6962
6963
6964
6965
6966
6967
6968
6969
6970
6971
6972
6973
6974
6975
6976
6977
6978
6979
6980
6981
6982
6983
6984
6985
6986
6987
6988
6989
6990
6991
6992
6993
6994
6995
6996
6997
6998
6999
7000
7001
7002
7003
7004
7005
7006
7007
7008
7009
7010
7011
7012
7013
7014
7015
7016
7017
7018
7019
7020
7021
7022
7023
7024
7025
7026
7027
7028
7029
7030
7031
7032
7033
7034
7035
7036
7037
7038
7039
7040
7041
7042
7043
7044
7045
7046
7047
7048
7049
7050
7051
7052
7053
7054
7055
7056
7057
7058
7059
7060
7061
7062
7063
7064
7065
7066
7067
7068
7069
7070
7071
7072
7073
7074
7075
7076
7077
7078
7079
7080
7081
7082
7083
7084
7085
7086
7087
7088
7089
7090
7091
7092
7093
7094
7095
7096
7097
7098
7099
7100
7101
7102
7103
7104
7105
7106
7107
7108
7109
7110
7111
7112
7113
7114
7115
7116
7117
7118
7119
7120
7121
7122
7123
7124
7125
7126
7127
7128
7129
7130
7131
7132
7133
7134
7135
7136
7137
7138
7139
7140
7141
7142
7143
7144
7145
7146
7147
7148
7149
7150
7151
7152
7153
7154
7155
7156
7157
7158
7159
7160
7161
7162
7163
7164
7165
7166
7167
7168
7169
7170
7171
7172
7173
7174
7175
7176
7177
7178
7179
7180
7181
7182
7183
7184
7185
7186
7187
7188
7189
7190
7191
7192
7193
7194
7195
7196
7197
7198
7199
7200
7201
7202
7203
7204
7205
7206
7207
7208
7209
7210
7211
7212
7213
7214
7215
7216
7217
7218
7219
7220
7221
7222
7223
7224
7225
7226
7227
7228
7229
7230
7231
7232
7233
7234
7235
7236
7237
7238
7239
7240
7241
7242
7243
7244
7245
7246
7247
7248
7249
7250
7251
7252
7253
7254
7255
7256
7257
7258
7259
7260
7261
7262
7263
7264
7265
7266
7267
7268
7269
7270
7271
7272
7273
7274
7275
7276
7277
7278
7279
7280
7281
7282
7283
7284
7285
7286
7287
7288
7289
7290
7291
7292
7293
7294
7295
7296
7297
7298
7299
7300
7301
7302
7303
7304
7305
7306
7307
7308
7309
7310
7311
7312
7313
7314
7315
7316
7317
7318
7319
7320
7321
7322
7323
7324
7325
7326
7327
7328
7329
7330
7331
7332
7333
7334
7335
7336
7337
7338
7339
7340
7341
7342
7343
7344
7345
7346
7347
7348
7349
7350
7351
7352
7353
7354
7355
7356
7357
7358
7359
7360
7361
7362
7363
7364
7365
7366
7367
7368
7369
7370
7371
7372
7373
7374
7375
7376
7377
7378
7379
7380
7381
7382
7383
7384
7385
7386
7387
7388
7389
7390
7391
7392
7393
7394
7395
7396
7397
7398
7399
7400
7401
7402
7403
7404
7405
7406
7407
7408
7409
7410
7411
7412
7413
7414
7415
7416
7417
7418
7419
7420
7421
7422
7423
7424
7425
7426
7427
7428
7429
7430
7431
7432
7433
7434
7435
7436
7437
7438
7439
7440
7441
7442
7443
7444
7445
7446
7447
7448
7449
7450
7451
7452
7453
7454
7455
7456
7457
7458
7459
7460
7461
7462
7463
7464
7465
7466
7467
7468
7469
7470
7471
7472
7473
7474
7475
7476
7477
7478
7479
7480
7481
7482
7483
7484
7485
7486
7487
7488
7489
7490
7491
7492
7493
7494
7495
7496
7497
7498
7499
7500
7501
7502
7503
7504
7505
7506
7507
7508
7509
7510
7511
7512
7513
7514
7515
7516
7517
7518
7519
7520
7521
7522
7523
7524
7525
7526
7527
7528
7529
7530
7531
7532
7533
7534
7535
7536
7537
7538
7539
7540
7541
7542
7543
7544
7545
7546
7547
7548
7549
7550
7551
7552
7553
7554
7555
7556
7557
7558
7559
7560
7561
7562
7563
7564
7565
7566
7567
7568
7569
7570
7571
7572
7573
7574
7575
7576
7577
7578
7579
7580
7581
7582
7583
7584
7585
7586
7587
7588
7589
7590
7591
7592
7593
7594
7595
7596
7597
7598
7599
7600
7601
7602
7603
7604
7605
7606
7607
7608
7609
7610
7611
7612
7613
7614
7615
7616
7617
7618
7619
7620
7621
7622
7623
7624
7625
7626
7627
7628
7629
7630
7631
7632
7633
7634
7635
7636
7637
7638
7639
7640
7641
7642
7643
7644
7645
7646
7647
7648
7649
7650
7651
7652
7653
7654
7655
7656
7657
7658
7659
7660
7661
7662
7663
7664
7665
7666
7667
7668
7669
7670
7671
7672
7673
7674
7675
7676
7677
7678
7679
7680
7681
7682
7683
7684
7685
7686
7687
7688
7689
7690
7691
7692
7693
7694
7695
7696
7697
7698
7699
7700
7701
7702
7703
7704
7705
7706
7707
7708
7709
7710
7711
7712
7713
7714
7715
7716
7717
7718
7719
7720
7721
7722
7723
7724
7725
7726
7727
7728
7729
7730
7731
7732
7733
7734
7735
7736
7737
7738
7739
7740
7741
7742
7743
7744
7745
7746
7747
7748
7749
7750
7751
7752
7753
7754
7755
7756
7757
7758
7759
7760
7761
7762
7763
7764
7765
7766
7767
7768
7769
7770
7771
7772
7773
7774
7775
7776
7777
7778
7779
7780
7781
7782
7783
7784
7785
7786
7787
7788
7789
7790
7791
7792
7793
7794
7795
7796
7797
7798
7799
7800
7801
7802
7803
7804
7805
7806
7807
7808
7809
7810
7811
7812
7813
7814
7815
7816
7817
7818
7819
7820
7821
7822
7823
7824
7825
7826
7827
7828
7829
7830
7831
7832
7833
7834
7835
7836
7837
7838
7839
7840
7841
7842
7843
7844
7845
7846
7847
7848
7849
7850
7851
7852
7853
7854
7855
7856
7857
7858
7859
7860
7861
7862
7863
7864
7865
7866
7867
7868
7869
7870
7871
7872
7873
7874
7875
7876
7877
7878
7879
7880
7881
7882
7883
7884
7885
7886
7887
7888
7889
7890
7891
7892
7893
7894
7895
7896
7897
7898
7899
7900
7901
7902
7903
7904
7905
7906
7907
7908
7909
7910
7911
7912
7913
7914
7915
7916
7917
7918
7919
7920
7921
7922
7923
7924
7925
7926
7927
7928
7929
7930
7931
7932
7933
7934
7935
7936
7937
7938
7939
7940
7941
7942
7943
7944
7945
7946
7947
7948
7949
7950
7951
7952
7953
7954
7955
7956
7957
7958
7959
7960
7961
7962
7963
7964
7965
7966
7967
7968
7969
7970
7971
7972
7973
7974
7975
7976
7977
7978
7979
7980
7981
7982
7983
7984
7985
7986
7987
7988
7989
7990
7991
7992
7993
7994
7995
7996
7997
7998
7999
8000
8001
8002
8003
8004
8005
8006
8007
8008
8009
8010
8011
8012
8013
8014
8015
8016
8017
8018
8019
8020
8021
8022
8023
8024
8025
8026
8027
8028
8029
8030
8031
8032
8033
8034
8035
8036
8037
8038
8039
8040
8041
8042
8043
8044
8045
8046
8047
8048
8049
8050
8051
8052
8053
8054
8055
8056
8057
8058
8059
8060
8061
8062
8063
8064
8065
8066
8067
8068
8069
8070
8071
8072
8073
8074
8075
8076
8077
8078
8079
8080
8081
8082
8083
8084
8085
8086
8087
8088
8089
8090
8091
8092
8093
8094
8095
8096
8097
8098
8099
8100
8101
8102
8103
8104
8105
8106
8107
8108
8109
8110
8111
8112
8113
8114
8115
8116
8117
8118
8119
8120
8121
8122
8123
8124
8125
8126
8127
8128
8129
8130
8131
8132
8133
8134
8135
8136
8137
8138
8139
8140
8141
8142
8143
8144
8145
8146
8147
8148
8149
8150
8151
8152
8153
8154
8155
8156
8157
8158
8159
8160
8161
8162
8163
8164
8165
8166
8167
8168
8169
8170
8171
8172
8173
8174
8175
8176
8177
8178
8179
8180
8181
8182
8183
8184
8185
8186
8187
8188
8189
8190
8191
8192
8193
8194
8195
8196
8197
8198
8199
8200
8201
8202
8203
8204
8205
8206
8207
8208
8209
8210
8211
8212
8213
8214
8215
8216
8217
8218
8219
8220
8221
8222
8223
8224
8225
8226
8227
8228
8229
8230
8231
8232
8233
8234
8235
8236
8237
8238
8239
8240
8241
8242
8243
8244
8245
8246
8247
8248
8249
8250
8251
8252
8253
8254
8255
8256
8257
8258
8259
8260
8261
8262
8263
8264
8265
8266
8267
8268
8269
8270
8271
8272
8273
8274
8275
8276
8277
8278
8279
8280
8281
8282
8283
8284
8285
8286
8287
8288
8289
8290
8291
8292
8293
8294
8295
8296
8297
8298
8299
8300
8301
8302
8303
8304
8305
8306
8307
8308
8309
8310
8311
8312
8313
8314
8315
8316
8317
8318
8319
8320
8321
8322
8323
8324
8325
8326
8327
8328
8329
8330
8331
8332
8333
8334
8335
8336
8337
8338
8339
8340
8341
8342
8343
8344
8345
8346
8347
8348
8349
8350
8351
8352
8353
8354
8355
8356
8357
8358
8359
8360
8361
8362
8363
8364
8365
8366
8367
8368
8369
8370
8371
8372
8373
8374
8375
8376
8377
8378
8379
8380
8381
8382
8383
8384
8385
8386
8387
8388
8389
8390
8391
8392
8393
8394
8395
8396
8397
8398
8399
8400
8401
8402
8403
8404
8405
8406
8407
8408
8409
8410
8411
8412
8413
8414
8415
8416
8417
8418
8419
8420
8421
8422
8423
8424
8425
8426
8427
8428
8429
8430
8431
8432
8433
8434
8435
8436
8437
8438
8439
8440
8441
8442
8443
8444
8445
8446
8447
8448
8449
8450
8451
8452
8453
8454
8455
8456
8457
8458
8459
8460
8461
8462
8463
8464
8465
8466
8467
8468
8469
8470
8471
8472
8473
8474
8475
8476
8477
8478
8479
8480
8481
8482
8483
8484
8485
8486
8487
8488
8489
8490
8491
8492
8493
8494
8495
8496
8497
8498
8499
8500
8501
8502
8503
8504
8505
8506
8507
8508
8509
8510
8511
8512
8513
8514
8515
8516
8517
8518
8519
8520
8521
8522
8523
8524
8525
8526
8527
8528
8529
8530
8531
8532
8533
8534
8535
8536
8537
8538
8539
8540
8541
8542
8543
8544
8545
8546
8547
8548
8549
8550
8551
8552
8553
8554
8555
8556
8557
8558
8559
8560
8561
8562
8563
8564
8565
8566
8567
8568
8569
8570
8571
8572
8573
8574
8575
8576
8577
8578
8579
8580
8581
8582
8583
8584
8585
8586
8587
8588
8589
8590
8591
8592
8593
8594
8595
8596
8597
8598
8599
8600
8601
8602
8603
8604
8605
8606
8607
8608
8609
8610
8611
8612
8613
8614
8615
8616
8617
8618
8619
8620
8621
8622
8623
8624
8625
8626
8627
8628
8629
8630
8631
8632
8633
8634
8635
8636
8637
8638
8639
8640
8641
8642
8643
8644
8645
8646
8647
8648
8649
8650
8651
8652
8653
8654
8655
8656
8657
8658
8659
8660
8661
8662
8663
8664
8665
8666
8667
8668
8669
8670
8671
8672
8673
8674
8675
8676
8677
8678
8679
8680
8681
8682
8683
8684
8685
8686
8687
8688
8689
8690
8691
8692
8693
8694
8695
8696
8697
8698
8699
8700
8701
8702
8703
8704
8705
8706
8707
8708
8709
8710
8711
8712
8713
8714
8715
8716
8717
8718
8719
8720
8721
8722
8723
8724
8725
8726
8727
8728
8729
8730
8731
8732
8733
8734
8735
8736
8737
8738
8739
8740
8741
8742
8743
8744
8745
8746
8747
8748
8749
8750
8751
8752
8753
8754
8755
8756
8757
8758
8759
8760
8761
8762
8763
8764
8765
8766
8767
8768
8769
8770
8771
8772
8773
8774
8775
8776
8777
8778
8779
8780
8781
8782
8783
8784
8785
8786
8787
8788
8789
8790
8791
8792
8793
8794
8795
8796
8797
8798
8799
8800
8801
8802
8803
8804
8805
8806
8807
8808
8809
8810
8811
8812
8813
8814
8815
8816
8817
8818
8819
8820
8821
8822
8823
8824
8825
8826
8827
8828
8829
8830
8831
8832
8833
8834
8835
8836
8837
8838
8839
8840
8841
8842
8843
8844
8845
8846
8847
8848
8849
8850
8851
8852
8853
8854
8855
8856
8857
8858
8859
8860
8861
8862
8863
8864
8865
8866
8867
8868
8869
8870
8871
8872
8873
8874
8875
8876
8877
8878
8879
8880
8881
8882
8883
8884
8885
8886
8887
8888
8889
8890
8891
8892
8893
8894
8895
8896
8897
8898
8899
8900
8901
8902
8903
8904
8905
8906
8907
8908
8909
8910
8911
8912
8913
8914
8915
8916
8917
8918
8919
8920
8921
8922
8923
8924
8925
8926
8927
8928
8929
8930
8931
8932
8933
8934
8935
8936
8937
8938
8939
8940
8941
8942
8943
8944
8945
8946
8947
8948
8949
8950
8951
8952
8953
8954
8955
8956
8957
8958
8959
8960
8961
8962
8963
8964
8965
8966
8967
8968
8969
8970
8971
8972
8973
8974
8975
8976
8977
8978
8979
8980
8981
8982
8983
8984
8985
8986
8987
8988
8989
8990
8991
8992
8993
8994
8995
8996
8997
8998
8999
9000
9001
9002
9003
9004
9005
9006
9007
9008
9009
9010
9011
9012
9013
9014
9015
9016
9017
9018
9019
9020
9021
9022
9023
9024
9025
9026
9027
9028
9029
9030
9031
9032
9033
9034
9035
9036
9037
9038
9039
9040
9041
9042
9043
9044
9045
9046
9047
9048
9049
9050
9051
9052
9053
9054
9055
9056
9057
9058
9059
9060
9061
9062
9063
9064
9065
9066
9067
9068
9069
9070
9071
9072
9073
9074
9075
9076
9077
9078
9079
9080
9081
9082
9083
9084
9085
9086
9087
9088
9089
9090
9091
9092
9093
9094
9095
9096
9097
9098
9099
9100
9101
9102
9103
9104
9105
9106
9107
9108
9109
9110
9111
9112
9113
9114
9115
9116
9117
9118
9119
9120
9121
9122
9123
9124
9125
9126
9127
9128
9129
9130
9131
9132
9133
9134
9135
9136
9137
9138
9139
9140
9141
9142
9143
9144
9145
9146
9147
9148
9149
9150
9151
9152
9153
9154
9155
9156
9157
9158
9159
9160
9161
9162
9163
9164
9165
9166
9167
9168
9169
9170
9171
9172
9173
9174
9175
9176
9177
9178
9179
9180
9181
9182
9183
9184
9185
9186
9187
9188
9189
9190
9191
9192
9193
9194
9195
9196
9197
9198
9199
9200
9201
9202
9203
9204
9205
9206
9207
9208
9209
9210
9211
9212
9213
9214
9215
9216
9217
9218
9219
9220
9221
9222
9223
9224
9225
9226
9227
9228
9229
9230
9231
9232
9233
9234
9235
9236
9237
9238
9239
9240
9241
9242
9243
9244
9245
9246
9247
9248
9249
9250
9251
9252
9253
9254
9255
9256
9257
9258
9259
9260
9261
9262
9263
9264
9265
9266
9267
9268
9269
9270
9271
9272
9273
9274
9275
9276
9277
9278
9279
9280
9281
9282
9283
9284
9285
9286
9287
9288
9289
9290
9291
9292
9293
9294
9295
9296
9297
9298
9299
9300
9301
9302
9303
9304
9305
9306
9307
9308
9309
9310
9311
9312
9313
9314
9315
9316
9317
9318
9319
9320
9321
9322
9323
9324
9325
9326
9327
9328
9329
9330
9331
9332
9333
9334
9335
9336
9337
9338
9339
9340
9341
9342
9343
9344
9345
9346
9347
9348
9349
9350
9351
9352
9353
9354
9355
9356
9357
9358
9359
9360
9361
9362
9363
9364
9365
9366
9367
9368
9369
9370
9371
9372
9373
9374
9375
9376
9377
9378
9379
9380
9381
9382
9383
9384
9385
9386
9387
9388
9389
9390
9391
9392
9393
9394
9395
9396
9397
9398
9399
9400
9401
9402
9403
9404
9405
9406
9407
9408
9409
9410
9411
9412
9413
9414
9415
9416
9417
9418
9419
9420
9421
9422
9423
9424
9425
9426
9427
9428
9429
9430
9431
9432
9433
9434
9435
9436
9437
9438
9439
9440
9441
9442
9443
9444
9445
9446
9447
9448
9449
9450
9451
9452
9453
9454
9455
9456
9457
9458
9459
9460
9461
9462
9463
9464
9465
9466
9467
9468
9469
9470
9471
9472
9473
9474
9475
9476
9477
9478
9479
9480
9481
9482
9483
9484
9485
9486
9487
9488
9489
9490
9491
9492
9493
9494
9495
9496
9497
9498
9499
9500
9501
9502
9503
9504
9505
9506
9507
9508
9509
9510
9511
9512
9513
9514
9515
9516
9517
9518
9519
9520
9521
9522
9523
9524
9525
9526
9527
9528
9529
9530
9531
9532
9533
9534
9535
9536
9537
9538
9539
9540
9541
9542
9543
9544
9545
9546
9547
9548
9549
9550
9551
9552
9553
9554
9555
9556
9557
9558
9559
9560
9561
9562
9563
9564
9565
9566
9567
9568
9569
9570
9571
9572
9573
9574
9575
9576
9577
9578
9579
9580
9581
9582
9583
9584
9585
9586
9587
9588
9589
9590
9591
9592
9593
9594
9595
9596
9597
9598
9599
9600
9601
9602
9603
9604
9605
9606
9607
9608
9609
9610
9611
9612
9613
9614
9615
9616
9617
9618
9619
9620
9621
9622
9623
9624
9625
9626
9627
9628
9629
9630
9631
9632
9633
9634
9635
9636
9637
9638
9639
9640
9641
9642
9643
9644
9645
9646
9647
9648
9649
9650
9651
9652
9653
9654
9655
9656
9657
9658
9659
9660
9661
9662
9663
9664
9665
9666
9667
9668
9669
9670
9671
9672
9673
9674
9675
9676
9677
9678
9679
9680
9681
9682
9683
9684
9685
9686
9687
9688
9689
9690
9691
9692
9693
9694
9695
9696
9697
9698
9699
9700
9701
9702
9703
9704
9705
9706
9707
9708
9709
9710
9711
9712
9713
9714
9715
9716
9717
9718
9719
9720
9721
9722
9723
9724
9725
9726
9727
9728
9729
9730
9731
9732
9733
9734
9735
9736
9737
9738
9739
9740
9741
9742
9743
9744
9745
9746
9747
9748
9749
9750
9751
9752
9753
9754
9755
9756
9757
9758
9759
9760
9761
9762
9763
9764
9765
9766
9767
9768
9769
9770
9771
9772
9773
9774
9775
9776
9777
9778
9779
9780
9781
9782
9783
9784
9785
9786
9787
9788
9789
9790
9791
9792
9793
9794
9795
9796
9797
9798
9799
9800
9801
9802
9803
9804
9805
9806
9807
9808
9809
9810
9811
9812
9813
9814
9815
9816
9817
9818
9819
9820
9821
9822
9823
9824
9825
9826
9827
9828
9829
9830
9831
9832
9833
9834
9835
9836
9837
9838
9839
9840
9841
9842
9843
9844
9845
9846
9847
9848
9849
9850
9851
9852
9853
9854
9855
9856
9857
9858
9859
9860
9861
9862
9863
9864
9865
9866
9867
9868
9869
9870
9871
9872
9873
9874
9875
9876
9877
9878
9879
9880
9881
9882
9883
9884
9885
9886
9887
9888
9889
9890
9891
9892
9893
9894
9895
9896
9897
9898
9899
9900
9901
9902
9903
9904
9905
9906
9907
9908
9909
9910
9911
9912
9913
9914
9915
9916
9917
9918
9919
9920
9921
9922
9923
9924
9925
9926
9927
9928
9929
9930
9931
9932
9933
9934
9935
9936
9937
9938
9939
9940
9941
9942
9943
9944
9945
9946
9947
9948
9949
9950
9951
9952
9953
9954
9955
9956
9957
9958
9959
9960
9961
9962
9963
9964
9965
9966
9967
9968
9969
9970
9971
9972
9973
9974
9975
9976
9977
9978
9979
9980
9981
9982
9983
9984
9985
9986
9987
9988
9989
9990
9991
9992
9993
9994
9995
9996
9997
9998
9999
10000
10001
10002
10003
10004
10005
10006
10007
10008
10009
10010
10011
10012
10013
10014
10015
10016
10017
10018
10019
10020
10021
10022
10023
10024
10025
10026
10027
10028
10029
10030
10031
10032
10033
10034
10035
10036
10037
10038
10039
10040
10041
10042
10043
10044
10045
10046
10047
10048
10049
10050
10051
10052
10053
10054
10055
10056
10057
10058
10059
10060
10061
10062
10063
10064
10065
10066
10067
10068
10069
10070
10071
10072
10073
10074
10075
10076
10077
10078
10079
10080
10081
10082
10083
10084
10085
10086
10087
10088
10089
10090
10091
10092
10093
10094
10095
10096
10097
10098
10099
10100
10101
10102
10103
10104
10105
10106
10107
10108
10109
10110
10111
10112
10113
10114
10115
10116
10117
10118
10119
10120
10121
10122
10123
10124
10125
10126
10127
10128
10129
10130
10131
10132
10133
10134
10135
10136
10137
10138
10139
10140
10141
10142
10143
10144
10145
10146
10147
10148
10149
10150
10151
10152
10153
10154
10155
10156
10157
10158
10159
10160
10161
10162
10163
10164
10165
10166
10167
10168
10169
10170
10171
10172
10173
10174
10175
10176
10177
10178
10179
10180
10181
10182
10183
10184
10185
10186
10187
10188
10189
10190
10191
10192
10193
10194
10195
10196
10197
10198
10199
10200
10201
10202
10203
10204
10205
10206
10207
10208
10209
10210
10211
10212
10213
10214
10215
10216
10217
10218
10219
10220
10221
10222
10223
10224
10225
10226
10227
10228
10229
10230
10231
10232
10233
10234
10235
10236
10237
10238
10239
10240
10241
10242
10243
10244
10245
10246
10247
10248
10249
10250
10251
10252
10253
10254
10255
10256
10257
10258
10259
10260
10261
10262
10263
10264
10265
10266
10267
10268
10269
10270
10271
10272
10273
10274
10275
10276
10277
10278
10279
10280
10281
10282
10283
10284
10285
10286
10287
10288
10289
10290
10291
10292
10293
10294
10295
10296
10297
10298
10299
10300
10301
10302
10303
10304
10305
10306
10307
10308
10309
10310
10311
10312
10313
10314
10315
10316
10317
10318
10319
10320
10321
10322
10323
10324
10325
10326
10327
10328
10329
10330
10331
10332
10333
10334
10335
10336
10337
10338
10339
10340
10341
10342
10343
10344
10345
10346
10347
10348
10349
10350
10351
10352
10353
10354
10355
10356
10357
10358
10359
10360
10361
10362
10363
10364
10365
10366
10367
10368
10369
10370
10371
10372
10373
10374
10375
10376
10377
10378
10379
10380
10381
10382
10383
10384
10385
10386
10387
10388
10389
10390
10391
10392
10393
10394
10395
10396
10397
10398
10399
10400
10401
10402
10403
10404
10405
10406
10407
10408
10409
10410
10411
10412
10413
10414
10415
10416
10417
10418
10419
10420
10421
10422
10423
10424
10425
10426
10427
10428
10429
10430
10431
10432
10433
10434
10435
10436
10437
10438
10439
10440
10441
10442
10443
10444
10445
10446
10447
10448
10449
10450
10451
10452
10453
10454
10455
10456
10457
10458
10459
10460
10461
10462
10463
10464
10465
10466
10467
10468
10469
10470
10471
10472
10473
10474
10475
10476
10477
10478
10479
10480
10481
10482
10483
10484
10485
10486
10487
10488
10489
10490
10491
10492
10493
10494
10495
10496
10497
10498
10499
10500
10501
10502
10503
10504
10505
10506
10507
10508
10509
10510
10511
10512
10513
10514
10515
10516
10517
10518
10519
10520
10521
10522
10523
10524
10525
10526
10527
10528
10529
10530
10531
10532
10533
10534
10535
10536
10537
10538
10539
10540
10541
10542
10543
10544
10545
10546
10547
10548
10549
10550
10551
10552
10553
10554
10555
10556
10557
10558
10559
10560
10561
10562
10563
10564
10565
10566
10567
10568
10569
10570
10571
10572
10573
10574
10575
10576
10577
10578
10579
10580
10581
10582
10583
10584
10585
10586
10587
10588
10589
10590
10591
10592
10593
10594
10595
10596
10597
10598
10599
10600
10601
10602
10603
10604
10605
10606
10607
10608
10609
10610
10611
10612
10613
10614
10615
10616
10617
10618
10619
10620
10621
10622
10623
10624
10625
10626
10627
10628
10629
10630
10631
10632
10633
10634
10635
10636
10637
10638
10639
10640
10641
10642
10643
10644
10645
10646
10647
10648
10649
10650
10651
10652
10653
10654
10655
10656
10657
10658
10659
10660
10661
10662
10663
10664
10665
10666
10667
10668
10669
10670
10671
10672
10673
10674
10675
10676
10677
10678
10679
10680
10681
10682
10683
10684
10685
10686
10687
10688
10689
10690
10691
10692
10693
10694
10695
10696
10697
10698
10699
10700
10701
10702
10703
10704
10705
10706
10707
10708
10709
10710
10711
10712
10713
10714
10715
10716
10717
10718
10719
10720
10721
10722
10723
10724
10725
10726
10727
10728
10729
10730
10731
10732
10733
10734
10735
10736
10737
10738
10739
10740
10741
10742
10743
10744
10745
10746
10747
10748
10749
10750
10751
10752
10753
10754
10755
10756
10757
10758
10759
10760
10761
10762
10763
10764
10765
10766
10767
10768
10769
10770
10771
10772
10773
10774
10775
10776
10777
10778
10779
10780
10781
10782
10783
10784
10785
10786
10787
10788
10789
10790
10791
10792
10793
10794
10795
10796
10797
10798
10799
10800
10801
10802
10803
10804
10805
10806
10807
10808
10809
10810
10811
10812
10813
10814
10815
10816
10817
10818
10819
10820
10821
10822
10823
10824
10825
10826
10827
10828
10829
10830
10831
10832
10833
10834
10835
10836
10837
10838
10839
10840
10841
10842
10843
10844
10845
10846
10847
10848
10849
10850
10851
10852
10853
10854
10855
10856
10857
10858
10859
10860
10861
10862
10863
10864
10865
10866
10867
10868
10869
10870
10871
10872
10873
10874
10875
10876
10877
10878
10879
10880
10881
10882
10883
10884
10885
10886
10887
10888
10889
10890
10891
10892
10893
10894
10895
10896
10897
10898
10899
10900
10901
10902
10903
10904
10905
10906
10907
10908
10909
10910
10911
10912
10913
10914
10915
10916
10917
10918
10919
10920
10921
10922
10923
10924
10925
10926
10927
10928
10929
10930
10931
10932
10933
10934
10935
10936
10937
10938
10939
10940
10941
10942
10943
10944
10945
10946
10947
10948
10949
10950
10951
10952
10953
10954
10955
10956
10957
10958
10959
10960
10961
10962
10963
10964
10965
10966
10967
10968
10969
10970
10971
10972
10973
10974
10975
10976
10977
10978
10979
10980
10981
10982
10983
10984
10985
10986
10987
10988
10989
10990
10991
10992
10993
10994
10995
10996
10997
10998
10999
11000
11001
11002
11003
11004
11005
11006
11007
11008
11009
11010
11011
11012
11013
11014
11015
11016
11017
11018
11019
11020
11021
11022
11023
11024
11025
11026
11027
11028
11029
11030
11031
11032
11033
11034
11035
11036
11037
11038
11039
11040
11041
11042
11043
11044
11045
11046
11047
11048
11049
11050
11051
11052
11053
11054
11055
11056
11057
11058
11059
11060
11061
11062
11063
11064
11065
11066
11067
11068
11069
11070
11071
11072
11073
11074
11075
11076
11077
11078
11079
11080
11081
11082
11083
11084
11085
11086
11087
11088
11089
11090
11091
11092
11093
11094
11095
11096
11097
11098
11099
11100
11101
11102
11103
11104
11105
11106
11107
11108
11109
11110
11111
11112
11113
11114
11115
11116
11117
11118
11119
11120
11121
11122
11123
11124
11125
11126
11127
11128
11129
11130
11131
11132
11133
11134
11135
11136
11137
11138
11139
11140
11141
11142
11143
11144
11145
11146
11147
11148
11149
11150
11151
11152
11153
11154
11155
11156
11157
11158
11159
11160
11161
11162
11163
11164
11165
11166
11167
11168
11169
11170
11171
11172
11173
11174
11175
11176
11177
11178
11179
11180
11181
11182
11183
11184
11185
11186
11187
11188
11189
11190
11191
11192
11193
11194
11195
11196
11197
11198
11199
11200
11201
11202
11203
11204
11205
11206
11207
11208
11209
11210
11211
11212
11213
11214
11215
11216
11217
11218
11219
11220
11221
11222
11223
11224
11225
11226
11227
11228
11229
11230
11231
11232
11233
11234
11235
11236
11237
11238
11239
11240
11241
11242
11243
11244
11245
11246
11247
11248
11249
11250
11251
11252
11253
11254
11255
11256
11257
11258
11259
11260
11261
11262
11263
11264
11265
11266
11267
11268
11269
11270
11271
11272
11273
11274
11275
11276
11277
11278
11279
11280
11281
11282
11283
11284
11285
11286
11287
11288
11289
11290
11291
11292
11293
11294
11295
11296
11297
11298
11299
11300
11301
11302
11303
11304
11305
11306
11307
11308
11309
11310
11311
11312
11313
11314
11315
11316
11317
11318
11319
11320
11321
11322
11323
11324
11325
11326
11327
11328
11329
11330
11331
11332
11333
11334
11335
11336
11337
11338
11339
11340
11341
11342
11343
11344
11345
11346
11347
11348
11349
11350
11351
11352
11353
11354
11355
11356
11357
11358
11359
11360
11361
11362
11363
11364
11365
11366
11367
11368
11369
11370
11371
11372
11373
11374
11375
11376
11377
11378
11379
11380
11381
11382
11383
11384
11385
11386
11387
11388
11389
11390
11391
11392
11393
11394
11395
11396
11397
11398
11399
11400
11401
11402
11403
11404
11405
11406
11407
11408
11409
11410
11411
11412
11413
11414
11415
11416
11417
11418
11419
11420
11421
11422
11423
11424
11425
11426
11427
11428
11429
11430
11431
11432
11433
11434
11435
11436
11437
11438
11439
11440
11441
11442
11443
11444
11445
11446
11447
11448
11449
11450
11451
11452
11453
11454
11455
11456
11457
11458
11459
11460
11461
11462
11463
11464
11465
11466
11467
11468
11469
11470
11471
11472
11473
11474
11475
11476
11477
11478
11479
11480
11481
11482
11483
11484
11485
11486
11487
11488
11489
11490
11491
11492
11493
11494
11495
11496
11497
11498
11499
11500
11501
11502
11503
11504
11505
11506
11507
11508
11509
11510
11511
11512
11513
11514
11515
11516
11517
11518
11519
11520
11521
11522
11523
11524
11525
11526
11527
11528
11529
11530
11531
11532
11533
11534
11535
11536
11537
11538
11539
11540
11541
11542
11543
11544
11545
11546
11547
11548
11549
11550
11551
11552
11553
11554
11555
11556
11557
11558
11559
11560
11561
11562
11563
11564
11565
11566
11567
11568
11569
11570
11571
11572
11573
11574
11575
11576
11577
11578
11579
11580
11581
11582
11583
11584
11585
11586
11587
11588
11589
11590
11591
11592
11593
11594
11595
11596
11597
11598
11599
11600
11601
11602
11603
11604
11605
11606
11607
11608
11609
11610
11611
11612
11613
11614
11615
11616
11617
11618
11619
11620
11621
11622
11623
11624
11625
11626
11627
11628
11629
11630
11631
11632
11633
11634
11635
11636
11637
11638
11639
11640
11641
11642
11643
11644
11645
11646
11647
11648
11649
11650
11651
11652
11653
11654
11655
11656
11657
11658
11659
11660
11661
11662
11663
11664
11665
11666
11667
11668
11669
11670
11671
11672
11673
11674
11675
11676
11677
11678
11679
11680
11681
11682
11683
11684
11685
11686
11687
11688
11689
11690
11691
11692
11693
11694
11695
11696
11697
11698
11699
11700
11701
11702
11703
11704
11705
11706
11707
11708
11709
11710
11711
11712
11713
11714
11715
11716
11717
11718
11719
11720
11721
11722
11723
11724
11725
11726
11727
11728
11729
11730
11731
11732
11733
11734
11735
11736
11737
11738
11739
11740
11741
11742
11743
11744
11745
11746
11747
11748
11749
11750
11751
11752
11753
11754
11755
11756
11757
11758
11759
11760
11761
11762
11763
11764
11765
11766
11767
11768
11769
11770
11771
11772
11773
11774
11775
11776
11777
11778
11779
11780
11781
11782
11783
11784
11785
11786
11787
11788
11789
11790
11791
11792
11793
11794
11795
11796
11797
11798
11799
11800
11801
11802
11803
11804
11805
11806
11807
11808
11809
11810
11811
11812
11813
11814
11815
11816
11817
11818
11819
11820
11821
11822
11823
11824
11825
11826
11827
11828
11829
11830
11831
11832
11833
11834
11835
11836
11837
11838
11839
11840
11841
11842
11843
11844
11845
11846
11847
11848
11849
11850
11851
11852
11853
11854
11855
11856
11857
11858
11859
11860
11861
11862
11863
11864
11865
11866
11867
11868
11869
11870
11871
11872
11873
11874
11875
11876
11877
11878
11879
11880
11881
11882
11883
11884
11885
11886
11887
11888
11889
11890
11891
11892
11893
11894
11895
11896
11897
11898
11899
11900
11901
11902
11903
11904
11905
11906
11907
11908
11909
11910
11911
11912
11913
11914
11915
11916
11917
11918
11919
11920
11921
11922
11923
11924
11925
11926
11927
11928
11929
11930
11931
11932
11933
11934
11935
11936
11937
11938
11939
11940
11941
11942
11943
11944
11945
11946
11947
11948
11949
11950
11951
11952
11953
11954
11955
11956
11957
11958
11959
11960
11961
11962
11963
11964
11965
11966
11967
11968
11969
11970
11971
11972
11973
11974
11975
11976
11977
11978
11979
11980
11981
11982
11983
11984
11985
11986
11987
11988
11989
11990
11991
11992
11993
11994
11995
11996
11997
11998
11999
12000
12001
12002
12003
12004
12005
12006
12007
12008
12009
12010
12011
12012
12013
12014
12015
12016
12017
12018
12019
12020
12021
12022
12023
12024
12025
12026
12027
12028
12029
12030
12031
12032
12033
12034
12035
12036
12037
12038
12039
12040
12041
12042
12043
12044
12045
12046
12047
12048
12049
12050
12051
12052
12053
12054
12055
12056
12057
12058
12059
12060
12061
12062
12063
12064
12065
12066
12067
12068
12069
12070
12071
12072
12073
12074
12075
12076
12077
12078
12079
12080
12081
12082
12083
12084
12085
12086
12087
12088
12089
12090
12091
12092
12093
12094
12095
12096
12097
12098
12099
12100
12101
12102
12103
12104
12105
12106
12107
12108
12109
12110
12111
12112
12113
12114
12115
12116
12117
12118
12119
12120
12121
12122
12123
12124
12125
12126
12127
12128
12129
12130
12131
12132
12133
12134
12135
12136
12137
12138
12139
12140
12141
12142
12143
12144
12145
12146
12147
12148
12149
12150
12151
12152
12153
12154
12155
12156
12157
12158
12159
12160
12161
12162
12163
12164
12165
12166
12167
12168
12169
12170
12171
12172
12173
12174
12175
12176
12177
12178
12179
12180
12181
12182
12183
12184
12185
12186
12187
12188
12189
12190
12191
12192
12193
12194
12195
12196
12197
12198
12199
12200
12201
12202
12203
12204
12205
12206
12207
12208
12209
12210
12211
12212
12213
12214
12215
12216
12217
12218
12219
12220
12221
12222
12223
12224
12225
12226
12227
12228
12229
12230
12231
12232
12233
12234
12235
12236
12237
12238
12239
12240
12241
12242
12243
12244
12245
12246
12247
12248
12249
12250
12251
12252
12253
12254
12255
12256
12257
12258
12259
12260
12261
12262
12263
12264
12265
12266
12267
12268
12269
12270
12271
12272
12273
12274
12275
12276
12277
12278
12279
12280
12281
12282
12283
12284
12285
12286
12287
12288
12289
12290
12291
12292
12293
12294
12295
12296
12297
12298
12299
12300
12301
12302
12303
12304
12305
12306
12307
12308
12309
12310
12311
12312
12313
12314
12315
12316
12317
12318
12319
12320
12321
12322
12323
12324
12325
12326
12327
12328
12329
12330
12331
12332
12333
12334
12335
12336
12337
12338
12339
12340
12341
12342
12343
12344
12345
12346
12347
12348
12349
12350
12351
12352
12353
12354
12355
12356
12357
12358
12359
12360
12361
12362
12363
12364
12365
12366
12367
12368
12369
12370
12371
12372
12373
12374
12375
12376
12377
12378
12379
12380
12381
12382
12383
12384
12385
12386
12387
12388
12389
12390
12391
12392
12393
12394
12395
12396
12397
12398
12399
12400
12401
12402
12403
12404
12405
12406
12407
12408
12409
12410
12411
12412
12413
12414
12415
12416
12417
12418
12419
12420
12421
12422
12423
12424
12425
12426
12427
12428
12429
12430
12431
12432
12433
12434
12435
12436
12437
12438
12439
12440
12441
12442
12443
12444
12445
12446
12447
12448
12449
12450
12451
12452
12453
12454
12455
12456
12457
12458
12459
12460
12461
12462
12463
12464
12465
12466
12467
12468
12469
12470
12471
12472
12473
12474
12475
12476
12477
12478
12479
12480
12481
12482
12483
12484
12485
12486
12487
12488
12489
12490
12491
12492
12493
12494
12495
12496
12497
12498
12499
12500
12501
12502
12503
12504
12505
12506
12507
12508
12509
12510
12511
12512
12513
12514
12515
12516
12517
12518
12519
12520
12521
12522
12523
12524
12525
12526
12527
12528
12529
12530
12531
12532
12533
12534
12535
12536
12537
12538
12539
12540
12541
12542
12543
12544
12545
12546
12547
12548
12549
12550
12551
12552
12553
12554
12555
12556
12557
12558
12559
12560
12561
12562
12563
12564
12565
12566
12567
12568
12569
12570
12571
12572
12573
12574
12575
12576
12577
12578
12579
12580
12581
12582
12583
12584
12585
12586
12587
12588
12589
12590
12591
12592
12593
12594
12595
12596
12597
12598
12599
12600
12601
12602
12603
12604
12605
12606
12607
12608
12609
12610
12611
12612
12613
12614
12615
12616
12617
12618
12619
12620
12621
12622
12623
12624
12625
12626
12627
12628
12629
12630
12631
12632
12633
12634
12635
12636
12637
12638
12639
12640
12641
12642
12643
12644
12645
12646
12647
12648
12649
12650
12651
12652
12653
12654
12655
12656
12657
12658
12659
12660
12661
12662
12663
12664
12665
12666
12667
12668
12669
12670
12671
12672
12673
12674
12675
12676
12677
12678
12679
12680
12681
12682
12683
12684
12685
12686
12687
12688
12689
12690
12691
12692
12693
12694
12695
12696
12697
12698
12699
12700
12701
12702
12703
12704
12705
12706
12707
12708
12709
12710
12711
12712
12713
12714
12715
12716
12717
12718
12719
12720
12721
12722
12723
12724
12725
12726
12727
12728
12729
12730
12731
12732
12733
12734
12735
12736
12737
12738
12739
12740
12741
12742
12743
12744
12745
12746
12747
12748
12749
12750
12751
12752
12753
12754
12755
12756
12757
12758
12759
12760
12761
12762
12763
12764
12765
12766
12767
12768
12769
12770
12771
12772
12773
12774
12775
12776
12777
12778
12779
12780
12781
12782
12783
12784
12785
12786
12787
12788
12789
12790
12791
12792
12793
12794
12795
12796
12797
12798
12799
12800
12801
12802
12803
12804
12805
12806
12807
12808
12809
12810
12811
12812
12813
12814
12815
12816
12817
12818
12819
12820
12821
12822
12823
12824
12825
12826
12827
12828
12829
12830
12831
12832
12833
12834
12835
12836
12837
12838
12839
12840
12841
12842
12843
12844
12845
12846
12847
12848
12849
12850
12851
12852
12853
12854
12855
12856
12857
12858
12859
12860
12861
12862
12863
12864
12865
12866
12867
12868
12869
12870
12871
12872
12873
12874
12875
12876
12877
12878
12879
12880
12881
12882
12883
12884
12885
12886
12887
12888
12889
12890
12891
12892
12893
12894
12895
12896
12897
12898
12899
12900
12901
12902
12903
12904
12905
12906
12907
12908
12909
12910
12911
12912
12913
12914
12915
12916
12917
12918
12919
12920
12921
12922
12923
12924
12925
12926
12927
12928
12929
12930
12931
12932
12933
12934
12935
12936
12937
12938
12939
12940
12941
12942
12943
12944
12945
12946
12947
12948
12949
12950
12951
12952
12953
12954
12955
12956
12957
12958
12959
12960
12961
12962
12963
12964
12965
12966
12967
12968
12969
12970
12971
12972
12973
12974
12975
12976
12977
12978
12979
12980
12981
12982
12983
12984
12985
12986
12987
12988
12989
12990
12991
12992
12993
12994
12995
12996
12997
12998
12999
13000
13001
13002
13003
13004
13005
13006
13007
13008
13009
13010
13011
13012
13013
13014
13015
13016
13017
13018
13019
13020
13021
13022
13023
13024
13025
13026
13027
13028
13029
13030
13031
13032
13033
13034
13035
13036
13037
13038
13039
13040
13041
13042
13043
13044
13045
13046
13047
13048
13049
13050
13051
13052
13053
13054
13055
13056
13057
13058
13059
13060
13061
13062
13063
13064
13065
13066
13067
13068
13069
13070
13071
13072
13073
13074
13075
13076
13077
13078
13079
13080
13081
13082
13083
13084
13085
13086
13087
13088
13089
13090
13091
13092
13093
13094
13095
13096
13097
13098
13099
13100
13101
13102
13103
13104
13105
13106
13107
13108
13109
13110
13111
13112
13113
13114
13115
13116
13117
13118
13119
13120
13121
13122
13123
13124
13125
13126
13127
13128
13129
13130
13131
13132
13133
13134
13135
13136
13137
13138
13139
13140
13141
13142
13143
13144
13145
13146
13147
13148
13149
13150
13151
13152
13153
13154
13155
13156
13157
13158
13159
13160
13161
13162
13163
13164
13165
13166
13167
13168
13169
13170
13171
13172
13173
13174
13175
13176
13177
13178
13179
13180
13181
13182
13183
13184
13185
13186
13187
13188
13189
13190
13191
13192
13193
13194
13195
13196
13197
13198
13199
13200
13201
13202
13203
13204
13205
13206
13207
13208
13209
13210
13211
13212
13213
13214
13215
13216
13217
13218
13219
13220
13221
13222
13223
13224
13225
13226
13227
13228
13229
13230
13231
13232
13233
13234
13235
13236
13237
13238
13239
13240
13241
13242
13243
13244
13245
13246
13247
13248
13249
13250
13251
13252
13253
13254
13255
13256
13257
13258
13259
13260
13261
13262
13263
13264
13265
13266
13267
13268
13269
13270
13271
13272
13273
13274
13275
13276
13277
13278
13279
13280
13281
13282
13283
13284
13285
13286
13287
13288
13289
13290
13291
13292
13293
13294
13295
13296
13297
13298
13299
13300
13301
13302
13303
13304
13305
13306
13307
13308
13309
13310
13311
13312
13313
13314
13315
13316
13317
13318
13319
13320
13321
13322
13323
13324
13325
13326
13327
13328
13329
13330
13331
13332
13333
13334
13335
13336
13337
13338
13339
13340
13341
13342
13343
13344
13345
13346
13347
13348
13349
13350
13351
13352
13353
13354
13355
13356
13357
13358
13359
13360
13361
13362
13363
13364
13365
13366
13367
13368
13369
13370
13371
13372
13373
13374
13375
13376
13377
13378
13379
13380
13381
13382
13383
13384
13385
13386
13387
13388
13389
13390
13391
13392
13393
13394
13395
13396
13397
13398
13399
13400
13401
13402
13403
13404
13405
13406
13407
13408
13409
13410
13411
13412
13413
13414
13415
13416
13417
13418
13419
13420
13421
13422
13423
13424
13425
13426
13427
13428
13429
13430
13431
13432
13433
13434
13435
13436
13437
13438
13439
13440
13441
13442
13443
13444
13445
13446
13447
13448
13449
13450
13451
13452
13453
13454
13455
13456
13457
13458
13459
13460
13461
13462
13463
13464
13465
13466
13467
13468
13469
13470
13471
13472
13473
13474
13475
13476
13477
13478
13479
13480
13481
13482
13483
13484
13485
13486
13487
13488
13489
13490
13491
13492
13493
13494
13495
13496
13497
13498
13499
13500
13501
13502
13503
13504
13505
13506
13507
13508
13509
13510
13511
13512
13513
13514
13515
13516
13517
13518
13519
13520
13521
13522
13523
13524
13525
13526
13527
13528
13529
13530
13531
13532
13533
13534
13535
13536
13537
13538
13539
13540
13541
13542
13543
13544
13545
13546
13547
13548
13549
13550
13551
13552
13553
13554
13555
13556
13557
13558
13559
13560
13561
13562
13563
13564
13565
13566
13567
13568
13569
13570
13571
13572
13573
13574
13575
13576
13577
13578
13579
13580
13581
13582
13583
13584
13585
13586
13587
13588
13589
13590
13591
13592
13593
13594
13595
13596
13597
13598
13599
13600
13601
13602
13603
13604
13605
13606
13607
13608
13609
13610
13611
13612
13613
13614
13615
13616
13617
13618
13619
13620
13621
13622
13623
13624
13625
13626
13627
13628
13629
13630
13631
13632
13633
13634
13635
13636
13637
13638
13639
13640
13641
13642
13643
13644
13645
13646
13647
13648
13649
13650
13651
13652
13653
13654
13655
13656
13657
13658
13659
13660
13661
13662
13663
13664
13665
13666
13667
13668
13669
13670
13671
13672
13673
13674
13675
13676
13677
13678
13679
13680
13681
13682
13683
13684
13685
13686
13687
13688
13689
13690
13691
13692
13693
13694
13695
13696
13697
13698
13699
13700
13701
13702
13703
13704
13705
13706
13707
13708
13709
13710
13711
13712
13713
13714
13715
13716
13717
13718
13719
13720
13721
13722
13723
13724
13725
13726
13727
13728
13729
13730
13731
13732
13733
13734
13735
13736
13737
13738
13739
13740
13741
13742
13743
13744
13745
13746
13747
13748
13749
13750
13751
13752
13753
13754
13755
13756
13757
13758
13759
13760
13761
13762
13763
13764
13765
13766
13767
13768
13769
13770
13771
13772
13773
13774
13775
13776
13777
13778
13779
13780
13781
13782
13783
13784
13785
13786
13787
13788
13789
13790
13791
13792
13793
13794
13795
13796
13797
13798
13799
13800
13801
13802
13803
13804
13805
13806
13807
13808
13809
13810
13811
13812
13813
13814
13815
13816
13817
13818
13819
13820
13821
13822
13823
13824
13825
13826
13827
13828
13829
13830
13831
13832
13833
13834
13835
13836
13837
13838
13839
13840
13841
13842
13843
13844
13845
13846
13847
13848
13849
13850
13851
13852
13853
13854
13855
13856
13857
13858
13859
13860
13861
13862
13863
13864
13865
13866
13867
13868
13869
13870
13871
13872
13873
13874
13875
13876
13877
13878
13879
13880
13881
13882
13883
13884
13885
13886
13887
13888
13889
13890
13891
13892
13893
13894
13895
13896
13897
13898
13899
13900
13901
13902
13903
13904
13905
13906
13907
13908
13909
13910
13911
13912
13913
13914
13915
13916
13917
13918
13919
13920
13921
13922
13923
13924
13925
13926
13927
13928
13929
13930
13931
13932
13933
13934
13935
13936
13937
13938
13939
13940
13941
13942
13943
13944
13945
13946
13947
13948
13949
13950
13951
13952
13953
13954
13955
13956
13957
13958
13959
13960
13961
13962
13963
13964
13965
13966
13967
13968
13969
13970
13971
13972
13973
13974
13975
13976
13977
13978
13979
13980
13981
13982
13983
13984
13985
13986
13987
13988
13989
13990
13991
13992
13993
13994
13995
13996
13997
13998
13999
14000
14001
14002
14003
14004
14005
14006
14007
14008
14009
14010
14011
14012
14013
14014
14015
14016
14017
14018
14019
14020
14021
14022
14023
14024
14025
14026
14027
14028
14029
14030
14031
14032
14033
14034
14035
14036
14037
14038
14039
14040
14041
14042
14043
14044
14045
14046
14047
14048
14049
14050
14051
14052
14053
14054
14055
14056
14057
14058
14059
14060
14061
14062
14063
14064
14065
14066
14067
14068
14069
14070
14071
14072
14073
14074
14075
14076
14077
14078
14079
14080
14081
14082
14083
14084
14085
14086
14087
14088
14089
14090
14091
14092
14093
14094
14095
14096
14097
14098
14099
14100
14101
14102
14103
14104
14105
14106
14107
14108
14109
14110
14111
14112
14113
14114
14115
14116
14117
14118
14119
14120
14121
14122
14123
14124
14125
14126
14127
14128
14129
14130
14131
14132
14133
14134
14135
14136
14137
14138
14139
14140
14141
14142
14143
14144
14145
14146
14147
14148
14149
14150
14151
14152
14153
14154
14155
14156
14157
14158
14159
14160
14161
14162
14163
14164
14165
14166
14167
14168
14169
14170
14171
14172
14173
14174
14175
14176
14177
14178
14179
14180
14181
14182
14183
14184
14185
14186
14187
14188
14189
14190
14191
14192
14193
14194
14195
14196
14197
14198
14199
14200
14201
14202
14203
14204
14205
14206
14207
14208
14209
14210
14211
14212
14213
14214
14215
14216
14217
14218
14219
14220
14221
14222
14223
14224
14225
14226
14227
14228
14229
14230
14231
14232
14233
14234
14235
14236
14237
14238
14239
14240
14241
14242
14243
14244
14245
14246
14247
14248
14249
14250
14251
14252
14253
14254
14255
14256
14257
14258
14259
14260
14261
14262
14263
14264
14265
14266
14267
14268
14269
14270
14271
14272
14273
14274
14275
14276
14277
14278
14279
14280
14281
14282
14283
14284
14285
14286
14287
14288
14289
14290
14291
14292
14293
14294
14295
14296
14297
14298
14299
14300
14301
14302
14303
14304
14305
14306
14307
14308
14309
14310
14311
14312
14313
14314
14315
14316
14317
14318
14319
14320
14321
14322
14323
14324
14325
14326
14327
14328
14329
14330
14331
14332
14333
14334
14335
14336
14337
14338
14339
14340
14341
14342
14343
14344
14345
14346
14347
14348
14349
14350
14351
14352
14353
14354
14355
14356
14357
14358
14359
14360
14361
14362
14363
14364
14365
14366
14367
14368
14369
14370
14371
14372
14373
14374
14375
14376
14377
14378
14379
14380
14381
14382
14383
14384
14385
14386
14387
14388
14389
14390
14391
14392
14393
14394
14395
14396
14397
14398
14399
14400
14401
14402
14403
14404
14405
14406
14407
14408
14409
14410
14411
14412
14413
14414
14415
14416
14417
14418
14419
14420
14421
14422
14423
14424
14425
14426
14427
14428
14429
14430
14431
14432
14433
14434
14435
14436
14437
14438
14439
14440
14441
14442
14443
14444
14445
14446
14447
14448
14449
14450
14451
14452
14453
14454
14455
14456
14457
14458
14459
14460
14461
14462
14463
14464
14465
14466
14467
14468
14469
14470
14471
14472
14473
14474
14475
14476
14477
14478
14479
14480
14481
14482
14483
14484
14485
14486
14487
14488
14489
14490
14491
14492
14493
14494
14495
14496
14497
14498
14499
14500
14501
14502
14503
14504
14505
14506
14507
14508
14509
14510
14511
14512
14513
14514
14515
14516
14517
14518
14519
14520
14521
14522
14523
14524
14525
14526
14527
14528
14529
14530
14531
14532
14533
14534
14535
14536
14537
14538
14539
14540
14541
14542
14543
14544
14545
14546
14547
14548
14549
14550
14551
14552
14553
14554
14555
14556
14557
14558
14559
14560
14561
14562
14563
14564
14565
14566
14567
14568
14569
14570
14571
14572
14573
14574
14575
14576
14577
14578
14579
14580
14581
14582
14583
14584
14585
14586
14587
14588
14589
14590
14591
14592
14593
14594
14595
14596
14597
14598
14599
14600
14601
14602
14603
14604
14605
14606
14607
14608
14609
14610
14611
14612
14613
14614
14615
14616
14617
14618
14619
14620
14621
14622
14623
14624
14625
14626
14627
14628
14629
14630
14631
14632
14633
14634
14635
14636
14637
14638
14639
14640
14641
14642
14643
14644
14645
14646
14647
14648
14649
14650
14651
14652
14653
14654
14655
14656
14657
14658
14659
14660
14661
14662
14663
14664
14665
14666
14667
14668
14669
14670
14671
14672
14673
14674
14675
14676
14677
14678
14679
14680
14681
14682
14683
14684
14685
14686
14687
14688
14689
14690
14691
14692
14693
14694
14695
14696
14697
14698
14699
14700
14701
14702
14703
14704
14705
14706
14707
14708
14709
14710
14711
14712
14713
14714
14715
14716
14717
14718
14719
14720
14721
14722
14723
14724
14725
14726
14727
14728
14729
14730
14731
14732
14733
14734
14735
14736
14737
14738
14739
14740
14741
14742
14743
14744
14745
14746
14747
14748
14749
14750
14751
14752
14753
14754
14755
14756
14757
14758
14759
14760
14761
14762
14763
14764
14765
14766
14767
14768
14769
14770
14771
14772
14773
14774
14775
14776
14777
14778
14779
14780
14781
14782
14783
14784
14785
14786
14787
14788
14789
14790
14791
14792
14793
14794
14795
14796
14797
14798
14799
14800
14801
14802
14803
14804
14805
14806
14807
14808
14809
14810
14811
14812
14813
14814
14815
14816
14817
14818
14819
14820
14821
14822
14823
14824
14825
14826
14827
14828
14829
14830
14831
14832
14833
14834
14835
14836
14837
14838
14839
14840
14841
14842
14843
14844
14845
14846
14847
14848
14849
14850
14851
14852
14853
14854
14855
14856
14857
14858
14859
14860
14861
14862
14863
14864
14865
14866
14867
14868
14869
14870
14871
14872
14873
14874
14875
14876
14877
14878
14879
14880
14881
14882
14883
14884
14885
14886
14887
14888
14889
14890
14891
14892
14893
14894
14895
14896
14897
14898
14899
14900
14901
14902
14903
14904
14905
14906
14907
14908
14909
14910
14911
14912
14913
14914
14915
14916
14917
14918
14919
14920
14921
14922
14923
14924
14925
14926
14927
14928
14929
14930
14931
14932
14933
14934
14935
14936
14937
14938
14939
14940
14941
14942
14943
14944
14945
14946
14947
14948
14949
14950
14951
14952
14953
14954
14955
14956
14957
14958
14959
14960
14961
14962
14963
14964
14965
14966
14967
14968
14969
14970
14971
14972
14973
14974
14975
14976
14977
14978
14979
14980
14981
14982
14983
14984
14985
14986
14987
14988
14989
14990
14991
14992
14993
14994
14995
14996
14997
14998
14999
15000
15001
15002
15003
15004
15005
15006
15007
15008
15009
15010
15011
15012
15013
15014
15015
15016
15017
15018
15019
15020
15021
15022
15023
15024
15025
15026
15027
15028
15029
15030
15031
15032
15033
15034
15035
15036
15037
15038
15039
15040
15041
15042
15043
15044
15045
15046
15047
15048
15049
15050
15051
15052
15053
15054
15055
15056
15057
15058
15059
15060
15061
15062
15063
15064
15065
15066
15067
15068
15069
15070
15071
15072
15073
15074
15075
15076
15077
15078
15079
15080
15081
15082
15083
15084
15085
15086
15087
15088
15089
15090
15091
15092
15093
15094
15095
15096
15097
15098
15099
15100
15101
15102
15103
15104
15105
15106
15107
15108
15109
15110
15111
15112
15113
15114
15115
15116
15117
15118
15119
15120
15121
15122
15123
15124
15125
15126
15127
15128
15129
15130
15131
15132
15133
15134
15135
15136
15137
15138
15139
15140
15141
15142
15143
15144
15145
15146
15147
15148
15149
15150
15151
15152
15153
15154
15155
15156
15157
15158
15159
15160
15161
15162
15163
15164
15165
15166
15167
15168
15169
15170
15171
15172
15173
15174
15175
15176
15177
15178
15179
15180
15181
15182
15183
15184
15185
15186
15187
15188
15189
15190
15191
15192
15193
15194
15195
15196
15197
15198
15199
15200
15201
15202
15203
15204
15205
15206
15207
15208
15209
15210
15211
15212
15213
15214
15215
15216
15217
15218
15219
15220
15221
15222
15223
15224
15225
15226
15227
15228
15229
15230
15231
15232
15233
15234
15235
15236
15237
15238
15239
15240
15241
15242
15243
15244
15245
15246
15247
15248
15249
15250
15251
15252
15253
15254
15255
15256
15257
15258
15259
15260
15261
15262
15263
15264
15265
15266
15267
15268
15269
15270
15271
15272
15273
15274
15275
15276
15277
15278
15279
15280
15281
15282
15283
15284
15285
15286
15287
15288
15289
15290
15291
15292
15293
15294
15295
15296
15297
15298
15299
15300
15301
15302
15303
15304
15305
15306
15307
15308
15309
15310
15311
15312
15313
15314
15315
15316
15317
15318
15319
15320
15321
15322
15323
15324
15325
15326
15327
15328
15329
15330
15331
15332
15333
15334
15335
15336
15337
15338
15339
15340
15341
15342
15343
15344
15345
15346
15347
15348
15349
15350
15351
15352
15353
15354
15355
15356
15357
15358
15359
15360
15361
15362
15363
15364
15365
15366
15367
15368
15369
15370
15371
15372
15373
15374
15375
15376
15377
15378
15379
15380
15381
15382
15383
15384
15385
15386
15387
15388
15389
15390
15391
15392
15393
15394
15395
15396
15397
15398
15399
15400
15401
15402
15403
15404
15405
15406
15407
15408
15409
15410
15411
15412
15413
15414
15415
15416
15417
15418
15419
15420
15421
15422
15423
15424
15425
15426
15427
15428
15429
15430
15431
15432
15433
15434
15435
15436
15437
15438
15439
15440
15441
15442
15443
15444
15445
15446
15447
15448
15449
15450
15451
15452
15453
15454
15455
15456
15457
15458
15459
15460
15461
15462
15463
15464
15465
15466
15467
15468
15469
15470
15471
15472
15473
15474
15475
15476
15477
15478
15479
15480
15481
15482
15483
15484
15485
15486
15487
15488
15489
15490
15491
15492
15493
15494
15495
15496
15497
15498
15499
15500
15501
15502
15503
15504
15505
15506
15507
15508
15509
15510
15511
15512
15513
15514
15515
15516
15517
15518
15519
15520
15521
15522
15523
15524
15525
15526
15527
15528
15529
15530
15531
15532
15533
15534
15535
15536
15537
15538
15539
15540
15541
15542
15543
15544
15545
15546
15547
15548
15549
15550
15551
15552
15553
15554
15555
15556
15557
15558
15559
15560
15561
15562
15563
15564
15565
15566
15567
15568
15569
15570
15571
15572
15573
15574
15575
15576
15577
15578
15579
15580
15581
15582
15583
15584
15585
15586
15587
15588
15589
15590
15591
15592
15593
15594
15595
15596
15597
15598
15599
15600
15601
15602
15603
15604
15605
15606
15607
15608
15609
15610
15611
15612
15613
15614
15615
15616
15617
15618
15619
15620
15621
15622
15623
15624
15625
15626
15627
15628
15629
15630
15631
15632
15633
15634
15635
15636
15637
15638
15639
15640
15641
15642
15643
15644
15645
15646
15647
15648
15649
15650
15651
15652
15653
15654
15655
15656
15657
15658
15659
15660
15661
15662
15663
15664
15665
15666
15667
15668
15669
15670
15671
15672
15673
15674
15675
15676
15677
15678
15679
15680
15681
15682
15683
15684
15685
15686
15687
15688
15689
15690
15691
15692
15693
15694
15695
15696
15697
15698
15699
15700
15701
15702
15703
15704
15705
15706
15707
15708
15709
15710
15711
15712
15713
15714
15715
15716
15717
15718
15719
15720
15721
15722
15723
15724
15725
15726
15727
15728
15729
15730
15731
15732
15733
15734
15735
15736
15737
15738
15739
15740
15741
15742
15743
15744
15745
15746
15747
15748
15749
15750
15751
15752
15753
15754
15755
15756
15757
15758
15759
15760
15761
15762
15763
15764
15765
15766
15767
15768
15769
15770
15771
15772
15773
15774
15775
15776
15777
15778
15779
15780
15781
15782
15783
15784
15785
15786
15787
15788
15789
15790
15791
15792
15793
15794
15795
15796
15797
15798
15799
15800
15801
15802
15803
15804
15805
15806
15807
15808
15809
15810
15811
15812
15813
15814
15815
15816
15817
15818
15819
15820
15821
15822
15823
15824
15825
15826
15827
15828
15829
15830
15831
15832
15833
15834
15835
15836
15837
15838
15839
15840
15841
15842
15843
15844
15845
15846
15847
15848
15849
15850
15851
15852
15853
15854
15855
15856
15857
15858
15859
15860
15861
15862
15863
15864
15865
15866
15867
15868
15869
15870
15871
15872
15873
15874
15875
15876
15877
15878
15879
15880
15881
15882
15883
15884
15885
15886
15887
15888
15889
15890
15891
15892
15893
15894
15895
15896
15897
15898
15899
15900
15901
15902
15903
15904
15905
15906
15907
15908
15909
15910
15911
15912
15913
15914
15915
15916
15917
15918
15919
15920
15921
15922
15923
15924
15925
15926
15927
15928
15929
15930
15931
15932
15933
15934
15935
15936
15937
15938
15939
15940
15941
15942
15943
15944
15945
15946
15947
15948
15949
15950
15951
15952
15953
15954
15955
15956
15957
15958
15959
15960
15961
15962
15963
15964
15965
15966
15967
15968
15969
15970
15971
15972
15973
15974
15975
15976
15977
15978
15979
15980
15981
15982
15983
15984
15985
15986
15987
15988
15989
15990
15991
15992
15993
15994
15995
15996
15997
15998
15999
16000
16001
16002
16003
16004
16005
16006
16007
16008
16009
16010
16011
16012
16013
16014
16015
16016
16017
16018
16019
16020
16021
16022
16023
16024
16025
16026
16027
16028
16029
16030
16031
16032
16033
16034
16035
16036
16037
16038
16039
16040
16041
16042
16043
16044
16045
16046
16047
16048
16049
16050
16051
16052
16053
16054
16055
16056
16057
16058
16059
16060
16061
16062
16063
16064
16065
16066
16067
16068
16069
16070
16071
16072
16073
16074
16075
16076
16077
16078
16079
16080
16081
16082
16083
16084
16085
16086
16087
16088
16089
16090
16091
16092
16093
16094
16095
16096
16097
16098
16099
16100
16101
16102
16103
16104
16105
16106
16107
16108
16109
16110
16111
16112
16113
16114
16115
16116
16117
16118
16119
16120
16121
16122
16123
16124
16125
16126
16127
16128
16129
16130
16131
16132
16133
16134
16135
16136
16137
16138
16139
16140
16141
16142
16143
16144
16145
16146
16147
16148
16149
16150
16151
16152
16153
16154
16155
16156
16157
16158
16159
16160
16161
16162
16163
16164
16165
16166
16167
16168
16169
16170
16171
16172
16173
16174
16175
16176
16177
16178
16179
16180
16181
16182
16183
16184
16185
16186
16187
16188
16189
16190
16191
16192
16193
16194
16195
16196
16197
16198
16199
16200
16201
16202
16203
16204
16205
16206
16207
16208
16209
16210
16211
16212
16213
16214
16215
16216
16217
16218
16219
16220
16221
16222
16223
16224
16225
16226
16227
16228
16229
16230
16231
16232
16233
16234
16235
16236
16237
16238
16239
16240
16241
16242
16243
16244
16245
16246
16247
16248
16249
16250
16251
16252
16253
16254
16255
16256
16257
16258
16259
16260
16261
16262
16263
16264
16265
16266
16267
16268
16269
16270
16271
16272
16273
16274
16275
16276
16277
16278
16279
16280
16281
16282
16283
16284
16285
16286
16287
16288
16289
16290
16291
16292
16293
16294
16295
16296
16297
16298
16299
16300
16301
16302
16303
16304
16305
16306
16307
16308
16309
16310
16311
16312
16313
16314
16315
16316
16317
16318
16319
16320
16321
16322
16323
16324
16325
16326
16327
16328
16329
16330
16331
16332
16333
16334
16335
16336
16337
16338
16339
16340
16341
16342
16343
16344
16345
16346
16347
16348
16349
16350
16351
16352
16353
16354
16355
16356
16357
16358
16359
16360
16361
16362
16363
16364
16365
16366
16367
16368
16369
16370
16371
16372
16373
16374
16375
16376
16377
16378
16379
16380
16381
16382
16383
16384
16385
16386
16387
16388
16389
16390
16391
16392
16393
16394
16395
16396
16397
16398
16399
16400
16401
16402
16403
16404
16405
16406
16407
16408
16409
16410
16411
16412
16413
16414
16415
16416
16417
16418
16419
16420
16421
16422
16423
16424
16425
16426
16427
16428
16429
16430
16431
16432
16433
16434
16435
16436
16437
16438
16439
16440
16441
16442
16443
16444
16445
16446
16447
16448
16449
16450
16451
16452
16453
16454
16455
16456
16457
16458
16459
16460
16461
16462
16463
16464
16465
16466
16467
16468
16469
16470
16471
16472
16473
16474
16475
16476
16477
16478
16479
16480
16481
16482
16483
16484
16485
16486
16487
16488
16489
16490
16491
16492
16493
16494
16495
16496
16497
16498
16499
16500
16501
16502
16503
16504
16505
16506
16507
16508
16509
16510
16511
16512
16513
16514
16515
16516
16517
16518
16519
16520
16521
16522
16523
16524
16525
16526
16527
16528
16529
16530
16531
16532
16533
16534
16535
16536
16537
16538
16539
16540
16541
16542
16543
16544
16545
16546
16547
16548
16549
16550
16551
16552
16553
16554
16555
16556
16557
16558
16559
16560
16561
16562
16563
16564
16565
16566
16567
16568
16569
16570
16571
16572
16573
16574
16575
16576
16577
16578
16579
16580
16581
16582
16583
16584
16585
16586
16587
16588
16589
16590
16591
16592
16593
16594
16595
16596
16597
16598
16599
16600
16601
16602
16603
16604
16605
16606
16607
16608
16609
16610
16611
16612
16613
16614
16615
16616
16617
16618
16619
16620
16621
16622
16623
16624
16625
16626
16627
16628
16629
16630
16631
16632
16633
16634
16635
16636
16637
16638
16639
16640
16641
16642
16643
16644
16645
16646
16647
16648
16649
16650
16651
16652
16653
16654
16655
16656
16657
16658
16659
16660
16661
16662
16663
16664
16665
16666
16667
16668
16669
16670
16671
16672
16673
16674
16675
16676
16677
16678
16679
16680
16681
16682
16683
16684
16685
16686
16687
16688
16689
16690
16691
16692
16693
16694
16695
16696
16697
16698
16699
16700
16701
16702
16703
16704
16705
16706
16707
16708
16709
16710
16711
16712
16713
16714
16715
16716
16717
16718
16719
16720
16721
16722
16723
16724
16725
16726
16727
16728
16729
16730
16731
16732
16733
16734
16735
16736
16737
16738
16739
16740
16741
16742
16743
16744
16745
16746
16747
16748
16749
16750
16751
16752
16753
16754
16755
16756
16757
16758
16759
16760
16761
16762
16763
16764
16765
16766
16767
16768
16769
16770
16771
16772
16773
16774
16775
16776
16777
16778
16779
16780
16781
16782
16783
16784
16785
16786
16787
16788
16789
16790
16791
16792
16793
16794
16795
16796
16797
16798
16799
16800
16801
16802
16803
16804
16805
16806
16807
16808
16809
16810
16811
16812
16813
16814
16815
16816
16817
16818
16819
16820
16821
16822
16823
16824
16825
16826
16827
16828
16829
16830
16831
16832
16833
16834
16835
16836
16837
16838
16839
16840
16841
16842
16843
16844
16845
16846
16847
16848
16849
16850
16851
16852
16853
16854
16855
16856
16857
16858
16859
16860
16861
16862
16863
16864
16865
16866
16867
16868
16869
16870
16871
16872
16873
16874
16875
16876
16877
16878
16879
16880
16881
16882
16883
16884
16885
16886
16887
16888
16889
16890
16891
16892
16893
16894
16895
16896
16897
16898
16899
16900
16901
16902
16903
16904
16905
16906
16907
16908
16909
16910
16911
16912
16913
16914
16915
16916
16917
16918
16919
16920
16921
16922
16923
16924
16925
16926
16927
16928
16929
16930
16931
16932
16933
16934
16935
16936
16937
16938
16939
16940
16941
16942
16943
16944
16945
16946
16947
16948
16949
16950
16951
16952
16953
16954
16955
16956
16957
16958
16959
16960
16961
16962
16963
16964
16965
16966
16967
16968
16969
16970
16971
16972
16973
16974
16975
16976
16977
16978
16979
16980
16981
16982
16983
16984
16985
16986
16987
16988
16989
16990
16991
16992
16993
16994
16995
16996
16997
16998
16999
17000
17001
17002
17003
17004
17005
17006
17007
17008
17009
17010
17011
17012
17013
17014
17015
17016
17017
17018
17019
17020
17021
17022
17023
17024
17025
17026
17027
17028
17029
17030
17031
17032
17033
17034
17035
17036
17037
17038
17039
17040
17041
17042
17043
17044
17045
17046
17047
17048
17049
17050
17051
17052
17053
17054
17055
17056
17057
17058
17059
17060
17061
17062
17063
17064
17065
17066
17067
17068
17069
17070
17071
17072
17073
17074
17075
17076
17077
17078
17079
17080
17081
17082
17083
17084
17085
17086
17087
17088
17089
17090
17091
17092
17093
17094
17095
17096
17097
17098
17099
17100
17101
17102
17103
17104
17105
17106
17107
17108
17109
17110
17111
17112
17113
17114
17115
17116
17117
17118
17119
17120
17121
17122
17123
17124
17125
17126
17127
17128
17129
17130
17131
17132
17133
17134
17135
17136
17137
17138
17139
17140
17141
17142
17143
17144
17145
17146
17147
17148
17149
17150
17151
17152
17153
17154
17155
17156
17157
17158
17159
17160
17161
17162
17163
17164
17165
17166
17167
17168
17169
17170
17171
17172
17173
17174
17175
17176
17177
17178
17179
17180
17181
17182
17183
17184
17185
17186
17187
17188
17189
17190
17191
17192
17193
17194
17195
17196
17197
17198
17199
17200
17201
17202
17203
17204
17205
17206
17207
17208
17209
17210
17211
17212
17213
17214
17215
17216
17217
17218
17219
17220
17221
17222
17223
17224
17225
17226
17227
17228
17229
17230
17231
17232
17233
17234
17235
17236
17237
17238
17239
17240
17241
17242
17243
17244
17245
17246
17247
17248
17249
17250
17251
17252
17253
17254
17255
17256
17257
17258
17259
17260
17261
17262
17263
17264
17265
17266
17267
17268
17269
17270
17271
17272
17273
17274
17275
17276
17277
17278
17279
17280
17281
17282
17283
17284
17285
17286
17287
17288
17289
17290
17291
17292
17293
17294
17295
17296
17297
17298
17299
17300
17301
17302
17303
17304
17305
17306
17307
17308
17309
17310
17311
17312
17313
17314
17315
17316
17317
17318
17319
17320
17321
17322
17323
17324
17325
17326
17327
17328
17329
17330
17331
17332
17333
17334
17335
17336
17337
17338
17339
17340
17341
17342
17343
17344
17345
17346
17347
17348
17349
17350
17351
17352
17353
17354
17355
17356
17357
17358
17359
17360
17361
17362
17363
17364
17365
17366
17367
17368
17369
17370
17371
17372
17373
17374
17375
17376
17377
17378
17379
17380
17381
17382
17383
17384
17385
17386
17387
17388
17389
17390
17391
17392
17393
17394
17395
17396
17397
17398
17399
17400
17401
17402
17403
17404
17405
17406
17407
17408
17409
17410
17411
17412
17413
17414
17415
17416
17417
17418
17419
17420
17421
17422
17423
17424
17425
17426
17427
17428
17429
17430
17431
17432
17433
17434
17435
17436
17437
17438
17439
17440
17441
17442
17443
17444
17445
17446
17447
17448
17449
17450
17451
17452
17453
17454
17455
17456
17457
17458
17459
17460
17461
17462
17463
17464
17465
17466
17467
17468
17469
17470
17471
17472
17473
17474
17475
17476
17477
17478
17479
17480
17481
17482
17483
17484
17485
17486
17487
17488
17489
17490
17491
17492
17493
17494
17495
17496
17497
17498
17499
17500
17501
17502
17503
17504
17505
17506
17507
17508
17509
17510
17511
17512
17513
17514
17515
17516
17517
17518
17519
17520
17521
17522
17523
17524
17525
17526
17527
17528
17529
17530
17531
17532
17533
17534
17535
17536
17537
17538
17539
17540
17541
17542
17543
17544
17545
17546
17547
17548
17549
17550
17551
17552
17553
17554
17555
17556
17557
17558
17559
17560
17561
17562
17563
17564
17565
17566
17567
17568
17569
17570
17571
17572
17573
17574
17575
17576
17577
17578
17579
17580
17581
17582
17583
17584
17585
17586
17587
17588
17589
17590
17591
17592
17593
17594
17595
17596
17597
17598
17599
17600
17601
17602
17603
17604
17605
17606
17607
17608
17609
17610
17611
17612
17613
17614
17615
17616
17617
17618
17619
17620
17621
17622
17623
17624
17625
17626
17627
17628
17629
17630
17631
17632
17633
17634
17635
17636
17637
17638
17639
17640
17641
17642
17643
17644
17645
17646
17647
17648
17649
17650
17651
17652
17653
17654
17655
17656
17657
17658
17659
17660
17661
17662
17663
17664
17665
17666
17667
17668
17669
17670
17671
17672
17673
17674
17675
17676
17677
17678
17679
17680
17681
17682
17683
17684
17685
17686
17687
17688
17689
17690
17691
17692
17693
17694
17695
17696
17697
17698
17699
17700
17701
17702
17703
17704
17705
17706
17707
17708
17709
17710
17711
17712
17713
17714
17715
17716
17717
17718
17719
17720
17721
17722
17723
17724
17725
17726
17727
17728
17729
17730
17731
17732
17733
17734
17735
17736
17737
17738
17739
17740
17741
17742
17743
17744
17745
17746
17747
17748
17749
17750
17751
17752
17753
17754
17755
17756
17757
17758
17759
17760
17761
17762
17763
17764
17765
17766
17767
17768
17769
17770
17771
17772
17773
17774
17775
17776
17777
17778
17779
17780
17781
17782
17783
17784
17785
17786
17787
17788
17789
17790
17791
17792
17793
17794
17795
17796
17797
17798
17799
17800
17801
17802
17803
17804
17805
17806
17807
17808
17809
17810
17811
17812
17813
17814
17815
17816
17817
17818
17819
17820
17821
17822
17823
17824
17825
17826
17827
17828
17829
17830
17831
17832
17833
17834
17835
17836
17837
17838
17839
17840
17841
17842
17843
17844
17845
17846
17847
17848
17849
17850
17851
17852
17853
17854
17855
17856
17857
17858
17859
17860
17861
17862
17863
17864
17865
17866
17867
17868
17869
17870
17871
17872
17873
17874
17875
17876
17877
17878
17879
17880
17881
17882
17883
17884
17885
17886
17887
17888
17889
17890
17891
17892
17893
17894
17895
17896
17897
17898
17899
17900
17901
17902
17903
17904
17905
17906
17907
17908
17909
17910
17911
17912
17913
17914
17915
17916
17917
17918
17919
17920
17921
17922
17923
17924
17925
17926
17927
17928
17929
17930
17931
17932
17933
17934
17935
17936
17937
17938
17939
17940
17941
17942
17943
17944
17945
17946
17947
17948
17949
17950
17951
17952
17953
17954
17955
17956
17957
17958
17959
17960
17961
17962
17963
17964
17965
17966
17967
17968
17969
17970
17971
17972
17973
17974
17975
17976
17977
17978
17979
17980
17981
17982
17983
17984
17985
17986
17987
17988
17989
17990
17991
17992
17993
17994
17995
17996
17997
17998
17999
18000
18001
18002
18003
18004
18005
18006
18007
18008
18009
18010
18011
18012
18013
18014
18015
18016
18017
18018
18019
18020
18021
18022
18023
18024
18025
18026
18027
18028
18029
18030
18031
18032
18033
18034
18035
18036
18037
18038
18039
18040
18041
18042
18043
18044
18045
18046
18047
18048
18049
18050
18051
18052
18053
18054
18055
18056
18057
18058
18059
18060
18061
18062
18063
18064
18065
18066
18067
18068
18069
18070
18071
18072
18073
18074
18075
18076
18077
18078
18079
18080
18081
18082
18083
18084
18085
18086
18087
18088
18089
18090
18091
18092
18093
18094
18095
18096
18097
18098
18099
18100
18101
18102
18103
18104
18105
18106
18107
18108
18109
18110
18111
18112
18113
18114
18115
18116
18117
18118
18119
18120
18121
18122
18123
18124
18125
18126
18127
18128
18129
18130
18131
18132
18133
18134
18135
18136
18137
18138
18139
18140
18141
18142
18143
18144
18145
18146
18147
18148
18149
18150
18151
18152
18153
18154
18155
18156
18157
18158
18159
18160
18161
18162
18163
18164
18165
18166
18167
18168
18169
18170
18171
18172
18173
18174
18175
18176
18177
18178
18179
18180
18181
18182
18183
18184
18185
18186
18187
18188
18189
18190
18191
18192
18193
18194
18195
18196
18197
18198
18199
18200
18201
18202
18203
18204
18205
18206
18207
18208
18209
18210
18211
18212
18213
18214
18215
18216
18217
18218
18219
18220
18221
18222
18223
18224
18225
18226
18227
18228
18229
18230
18231
18232
18233
18234
18235
18236
18237
18238
18239
18240
18241
18242
18243
18244
18245
18246
18247
18248
18249
18250
18251
18252
18253
18254
18255
18256
18257
18258
18259
18260
18261
18262
18263
18264
18265
18266
18267
18268
18269
18270
18271
18272
18273
18274
18275
18276
18277
18278
18279
18280
18281
18282
18283
18284
18285
18286
18287
18288
18289
18290
18291
18292
18293
18294
18295
18296
18297
18298
18299
18300
18301
18302
18303
18304
18305
18306
18307
18308
18309
18310
18311
18312
18313
18314
18315
18316
18317
18318
18319
18320
18321
18322
18323
18324
18325
18326
18327
18328
18329
18330
18331
18332
18333
18334
18335
18336
18337
18338
18339
18340
18341
18342
18343
18344
18345
18346
18347
18348
18349
18350
18351
18352
18353
18354
18355
18356
18357
18358
18359
18360
18361
18362
18363
18364
18365
18366
18367
18368
18369
18370
18371
18372
18373
18374
18375
18376
18377
18378
18379
18380
18381
18382
18383
18384
18385
18386
18387
18388
18389
18390
18391
18392
18393
18394
18395
18396
18397
18398
18399
18400
18401
18402
18403
18404
18405
18406
18407
18408
18409
18410
18411
18412
18413
18414
18415
18416
18417
18418
18419
18420
18421
18422
18423
18424
18425
18426
18427
18428
18429
18430
18431
18432
18433
18434
18435
18436
18437
18438
18439
18440
18441
18442
18443
18444
18445
18446
18447
18448
18449
18450
18451
18452
18453
18454
18455
18456
18457
18458
18459
18460
18461
18462
18463
18464
18465
18466
18467
18468
18469
18470
18471
18472
18473
18474
18475
18476
18477
18478
18479
18480
18481
18482
18483
18484
18485
18486
18487
18488
18489
18490
18491
18492
18493
18494
18495
18496
18497
18498
18499
18500
18501
18502
18503
18504
18505
18506
18507
18508
18509
18510
18511
18512
18513
18514
18515
18516
18517
18518
18519
18520
18521
18522
18523
18524
18525
18526
18527
18528
18529
18530
18531
18532
18533
18534
18535
18536
18537
18538
18539
18540
18541
18542
18543
18544
18545
18546
18547
18548
18549
18550
18551
18552
18553
18554
18555
18556
18557
18558
18559
18560
18561
18562
18563
18564
18565
18566
18567
18568
18569
18570
18571
18572
18573
18574
18575
18576
18577
18578
18579
18580
18581
18582
18583
18584
18585
18586
18587
18588
18589
18590
18591
18592
18593
18594
18595
18596
18597
18598
18599
18600
18601
18602
18603
18604
18605
18606
18607
18608
18609
18610
18611
18612
18613
18614
18615
18616
18617
18618
18619
18620
18621
18622
18623
18624
18625
18626
18627
18628
18629
18630
18631
18632
18633
18634
18635
18636
18637
18638
18639
18640
18641
18642
18643
18644
18645
18646
18647
18648
18649
18650
18651
18652
18653
18654
18655
18656
18657
18658
18659
18660
18661
18662
18663
18664
18665
18666
18667
18668
18669
18670
18671
18672
18673
18674
18675
18676
18677
18678
18679
18680
18681
18682
18683
18684
18685
18686
18687
18688
18689
18690
18691
18692
18693
18694
18695
18696
18697
18698
18699
18700
18701
18702
18703
18704
18705
18706
18707
18708
18709
18710
18711
18712
18713
18714
18715
18716
18717
18718
18719
18720
18721
18722
18723
18724
18725
18726
18727
18728
18729
18730
18731
18732
18733
18734
18735
18736
18737
18738
18739
18740
18741
18742
18743
18744
18745
18746
18747
18748
18749
18750
18751
18752
18753
18754
18755
18756
18757
18758
18759
18760
18761
18762
18763
18764
18765
18766
18767
18768
18769
18770
18771
18772
18773
18774
18775
18776
18777
18778
18779
18780
18781
18782
18783
18784
18785
18786
18787
18788
18789
18790
18791
18792
18793
18794
18795
18796
18797
18798
18799
18800
18801
18802
18803
18804
18805
18806
18807
18808
18809
18810
18811
18812
18813
18814
18815
18816
18817
18818
18819
18820
18821
18822
18823
18824
18825
18826
18827
18828
18829
18830
18831
18832
18833
18834
18835
18836
18837
18838
18839
18840
18841
18842
18843
18844
18845
18846
18847
18848
18849
18850
18851
18852
18853
18854
18855
18856
18857
18858
18859
18860
18861
18862
18863
18864
18865
18866
18867
18868
18869
18870
18871
18872
18873
18874
18875
18876
18877
18878
18879
18880
18881
18882
18883
18884
18885
18886
18887
18888
18889
18890
18891
18892
18893
18894
18895
18896
18897
18898
18899
18900
18901
18902
18903
18904
18905
18906
18907
18908
18909
18910
18911
18912
18913
18914
18915
18916
18917
18918
18919
18920
18921
18922
18923
18924
18925
18926
18927
18928
18929
18930
18931
18932
18933
18934
18935
18936
18937
18938
18939
18940
18941
18942
18943
18944
18945
18946
18947
18948
18949
18950
18951
18952
18953
18954
18955
18956
18957
18958
18959
18960
18961
18962
18963
18964
18965
18966
18967
18968
18969
18970
18971
18972
18973
18974
18975
18976
18977
18978
18979
18980
18981
18982
18983
18984
18985
18986
18987
18988
18989
18990
18991
18992
18993
18994
18995
18996
18997
18998
18999
19000
19001
19002
19003
19004
19005
19006
19007
19008
19009
19010
19011
19012
19013
19014
19015
19016
19017
19018
19019
19020
19021
19022
19023
19024
19025
19026
19027
19028
19029
19030
19031
19032
19033
19034
19035
19036
19037
19038
19039
19040
19041
19042
19043
19044
19045
19046
19047
19048
19049
19050
19051
19052
19053
19054
19055
19056
19057
19058
19059
19060
19061
19062
19063
19064
19065
19066
19067
19068
19069
19070
19071
19072
19073
19074
19075
19076
19077
19078
19079
19080
19081
19082
19083
19084
19085
19086
19087
19088
19089
19090
19091
19092
19093
19094
19095
19096
19097
19098
19099
19100
19101
19102
19103
19104
19105
19106
19107
19108
19109
19110
19111
19112
19113
19114
19115
19116
19117
19118
19119
19120
19121
19122
19123
19124
19125
19126
19127
19128
19129
19130
19131
19132
19133
19134
19135
19136
19137
19138
19139
19140
19141
19142
19143
19144
19145
19146
19147
19148
19149
19150
19151
19152
19153
19154
19155
19156
19157
19158
19159
19160
19161
19162
19163
19164
19165
19166
19167
19168
19169
19170
19171
19172
19173
19174
19175
19176
19177
19178
19179
19180
19181
19182
19183
19184
19185
19186
19187
19188
19189
19190
19191
19192
19193
19194
19195
19196
19197
19198
19199
19200
19201
19202
19203
19204
19205
19206
19207
19208
19209
19210
19211
19212
19213
19214
19215
19216
19217
19218
19219
19220
19221
19222
19223
19224
19225
19226
19227
19228
19229
19230
19231
19232
19233
19234
19235
19236
19237
19238
19239
19240
19241
19242
19243
19244
19245
19246
19247
19248
19249
19250
19251
19252
19253
19254
19255
19256
19257
19258
19259
19260
19261
19262
19263
19264
19265
19266
19267
19268
19269
19270
19271
19272
19273
19274
19275
19276
19277
19278
19279
19280
19281
19282
19283
19284
19285
19286
19287
19288
19289
19290
19291
19292
19293
19294
19295
19296
19297
19298
19299
19300
19301
19302
19303
19304
19305
19306
19307
19308
19309
19310
19311
19312
19313
19314
19315
19316
19317
19318
19319
19320
19321
19322
19323
19324
19325
19326
19327
19328
19329
19330
19331
19332
19333
19334
19335
19336
19337
19338
19339
19340
19341
19342
19343
19344
19345
19346
19347
19348
19349
19350
19351
19352
19353
19354
19355
19356
19357
19358
19359
19360
19361
19362
19363
19364
19365
19366
19367
19368
19369
19370
19371
19372
19373
19374
19375
19376
19377
19378
19379
19380
19381
19382
19383
19384
19385
19386
19387
19388
19389
19390
19391
19392
19393
19394
19395
19396
19397
19398
19399
19400
19401
19402
19403
19404
19405
19406
19407
19408
19409
19410
19411
19412
19413
19414
19415
19416
19417
19418
19419
19420
19421
19422
19423
19424
19425
19426
19427
19428
19429
19430
19431
19432
19433
19434
19435
19436
19437
19438
19439
19440
19441
19442
19443
19444
19445
19446
19447
19448
19449
19450
19451
19452
19453
19454
19455
19456
19457
19458
19459
19460
19461
19462
19463
19464
19465
19466
19467
19468
19469
19470
19471
19472
19473
19474
19475
19476
19477
19478
19479
19480
19481
19482
19483
19484
19485
19486
19487
19488
19489
19490
19491
19492
19493
19494
19495
19496
19497
19498
19499
19500
19501
19502
19503
19504
19505
19506
19507
19508
19509
19510
19511
19512
19513
19514
19515
19516
19517
19518
19519
19520
19521
19522
19523
19524
19525
19526
19527
19528
19529
19530
19531
19532
19533
19534
19535
19536
19537
19538
19539
19540
19541
19542
19543
19544
19545
19546
19547
19548
19549
19550
19551
19552
19553
19554
19555
19556
19557
19558
19559
19560
19561
19562
19563
19564
19565
19566
19567
19568
19569
19570
19571
19572
19573
19574
19575
19576
19577
19578
19579
19580
19581
19582
19583
19584
19585
19586
19587
19588
19589
19590
19591
19592
19593
19594
19595
19596
19597
19598
19599
19600
19601
19602
19603
19604
19605
19606
19607
19608
19609
19610
19611
19612
19613
19614
19615
19616
19617
19618
19619
19620
19621
19622
19623
19624
19625
19626
19627
19628
19629
19630
19631
19632
19633
19634
19635
19636
19637
19638
19639
19640
19641
19642
19643
19644
19645
19646
19647
19648
19649
19650
19651
19652
19653
19654
19655
19656
19657
19658
19659
19660
19661
19662
19663
19664
19665
19666
19667
19668
19669
19670
19671
19672
19673
19674
19675
19676
19677
19678
19679
19680
19681
19682
19683
19684
19685
19686
19687
19688
19689
19690
19691
19692
19693
19694
19695
19696
19697
19698
19699
19700
19701
19702
19703
19704
19705
19706
19707
19708
19709
19710
19711
19712
19713
19714
19715
19716
19717
19718
19719
19720
19721
19722
19723
19724
19725
19726
19727
19728
19729
19730
19731
19732
19733
19734
19735
19736
19737
19738
19739
19740
19741
19742
19743
19744
19745
19746
19747
19748
19749
19750
19751
19752
19753
19754
19755
19756
19757
19758
19759
19760
19761
19762
19763
19764
19765
19766
19767
19768
19769
19770
19771
19772
19773
19774
19775
19776
19777
19778
19779
19780
19781
19782
19783
19784
19785
19786
19787
19788
19789
19790
19791
19792
19793
19794
19795
19796
19797
19798
19799
19800
19801
19802
19803
19804
19805
19806
19807
19808
19809
19810
19811
19812
19813
19814
19815
19816
19817
19818
19819
19820
19821
19822
19823
19824
19825
19826
19827
19828
19829
19830
19831
19832
19833
19834
19835
19836
19837
19838
19839
19840
19841
19842
19843
19844
19845
19846
19847
19848
19849
19850
19851
19852
19853
19854
19855
19856
19857
19858
19859
19860
19861
19862
19863
19864
19865
19866
19867
19868
19869
19870
19871
19872
19873
19874
19875
19876
19877
19878
19879
19880
19881
19882
19883
19884
19885
19886
19887
19888
19889
19890
19891
19892
19893
19894
19895
19896
19897
19898
19899
19900
19901
19902
19903
19904
19905
19906
19907
19908
19909
19910
19911
19912
19913
19914
19915
19916
19917
19918
19919
19920
19921
19922
19923
19924
19925
19926
19927
19928
19929
19930
19931
19932
19933
19934
19935
19936
19937
19938
19939
19940
19941
19942
19943
19944
19945
19946
19947
19948
19949
19950
19951
19952
19953
19954
19955
19956
19957
19958
19959
19960
19961
19962
19963
19964
19965
19966
19967
19968
19969
19970
19971
19972
19973
19974
19975
19976
19977
19978
19979
19980
19981
19982
19983
19984
19985
19986
19987
19988
19989
19990
19991
19992
19993
19994
19995
19996
19997
19998
19999
20000
20001
20002
20003
20004
20005
20006
20007
20008
20009
20010
20011
20012
20013
20014
20015
20016
20017
20018
20019
20020
20021
20022
20023
20024
20025
20026
20027
20028
20029
20030
20031
20032
20033
20034
20035
20036
20037
20038
20039
20040
20041
20042
20043
20044
20045
20046
20047
20048
20049
20050
20051
20052
20053
20054
20055
20056
20057
20058
20059
20060
20061
20062
20063
20064
20065
20066
20067
20068
20069
20070
20071
20072
20073
20074
20075
20076
20077
20078
20079
20080
20081
20082
20083
20084
20085
20086
20087
20088
20089
20090
20091
20092
20093
20094
20095
20096
20097
20098
20099
20100
20101
20102
20103
20104
20105
20106
20107
20108
20109
20110
20111
20112
20113
20114
20115
20116
20117
20118
20119
20120
20121
20122
20123
20124
20125
20126
20127
20128
20129
20130
20131
20132
20133
20134
20135
20136
20137
20138
20139
20140
20141
20142
20143
20144
20145
20146
20147
20148
20149
20150
20151
20152
20153
20154
20155
20156
20157
20158
20159
20160
20161
20162
20163
20164
20165
20166
20167
20168
20169
20170
20171
20172
20173
20174
20175
20176
20177
20178
20179
20180
20181
20182
20183
20184
20185
20186
20187
20188
20189
20190
20191
20192
20193
20194
20195
20196
20197
20198
20199
20200
20201
20202
20203
20204
20205
20206
20207
20208
20209
20210
20211
20212
20213
20214
20215
20216
20217
20218
20219
20220
20221
20222
20223
20224
20225
20226
20227
20228
20229
20230
20231
20232
20233
20234
20235
20236
20237
20238
20239
20240
20241
20242
20243
20244
20245
20246
20247
20248
20249
20250
20251
20252
20253
20254
20255
20256
20257
20258
20259
20260
20261
20262
20263
20264
20265
20266
20267
20268
20269
20270
20271
20272
20273
20274
20275
20276
20277
20278
20279
20280
20281
20282
20283
20284
20285
20286
20287
20288
20289
20290
20291
20292
20293
20294
20295
20296
20297
20298
20299
20300
20301
20302
20303
20304
20305
20306
20307
20308
20309
20310
20311
20312
20313
20314
20315
20316
20317
20318
20319
20320
20321
20322
20323
20324
20325
20326
20327
20328
20329
20330
20331
20332
20333
20334
20335
20336
20337
20338
20339
20340
20341
20342
20343
20344
20345
20346
20347
20348
20349
20350
20351
20352
20353
20354
20355
20356
20357
20358
20359
20360
20361
20362
20363
20364
20365
20366
20367
20368
20369
20370
20371
20372
20373
20374
20375
20376
20377
20378
20379
20380
20381
20382
20383
20384
20385
20386
20387
20388
20389
20390
20391
20392
20393
20394
20395
20396
20397
20398
20399
20400
20401
20402
20403
20404
20405
20406
20407
20408
20409
20410
20411
20412
20413
20414
20415
20416
20417
20418
20419
20420
20421
20422
20423
20424
20425
20426
20427
20428
20429
20430
20431
20432
20433
20434
20435
20436
20437
20438
20439
20440
20441
20442
20443
20444
20445
20446
20447
20448
20449
20450
20451
20452
20453
20454
20455
20456
20457
20458
20459
20460
20461
20462
20463
20464
20465
20466
20467
20468
20469
20470
20471
20472
20473
20474
20475
20476
20477
20478
20479
20480
20481
20482
20483
20484
20485
20486
20487
20488
20489
20490
20491
20492
20493
20494
20495
20496
20497
20498
20499
20500
20501
20502
20503
20504
20505
20506
20507
20508
20509
20510
20511
20512
20513
20514
20515
20516
20517
20518
20519
20520
20521
20522
20523
20524
20525
20526
20527
20528
20529
20530
20531
20532
20533
20534
20535
20536
20537
20538
20539
20540
20541
20542
20543
20544
20545
20546
20547
20548
20549
20550
20551
20552
20553
20554
20555
20556
20557
20558
20559
20560
20561
20562
20563
20564
20565
20566
20567
20568
20569
20570
20571
20572
20573
20574
20575
20576
20577
20578
20579
20580
20581
20582
20583
20584
20585
20586
20587
20588
20589
20590
20591
20592
20593
20594
20595
20596
20597
20598
20599
20600
20601
20602
20603
20604
20605
20606
20607
20608
20609
20610
20611
20612
20613
20614
20615
20616
20617
20618
20619
20620
20621
20622
20623
20624
20625
20626
20627
20628
20629
20630
20631
20632
20633
20634
20635
20636
20637
20638
20639
20640
20641
20642
20643
20644
20645
20646
20647
20648
20649
20650
20651
20652
20653
20654
20655
20656
20657
20658
20659
20660
20661
20662
20663
20664
20665
20666
20667
20668
20669
20670
20671
20672
20673
20674
20675
20676
20677
20678
20679
20680
20681
20682
20683
20684
20685
20686
20687
20688
20689
20690
20691
20692
20693
20694
20695
20696
20697
20698
20699
20700
20701
20702
20703
20704
20705
20706
20707
20708
20709
20710
20711
20712
20713
20714
20715
20716
20717
20718
20719
20720
20721
20722
20723
20724
20725
20726
20727
20728
20729
20730
20731
20732
20733
20734
20735
20736
20737
20738
20739
20740
20741
20742
20743
20744
20745
20746
20747
20748
20749
20750
20751
20752
20753
20754
20755
20756
20757
20758
20759
20760
20761
20762
20763
20764
20765
20766
20767
20768
20769
20770
20771
20772
20773
20774
20775
20776
20777
20778
20779
20780
20781
20782
20783
20784
20785
20786
20787
20788
20789
20790
20791
20792
20793
20794
20795
20796
20797
20798
20799
20800
20801
20802
20803
20804
20805
20806
20807
20808
20809
20810
20811
20812
20813
20814
20815
20816
20817
20818
20819
20820
20821
20822
20823
20824
20825
20826
20827
20828
20829
20830
20831
20832
20833
20834
20835
20836
20837
20838
20839
20840
20841
20842
20843
20844
20845
20846
20847
20848
20849
20850
20851
20852
20853
20854
20855
20856
20857
20858
20859
20860
20861
20862
20863
20864
20865
20866
20867
20868
20869
20870
20871
20872
20873
20874
20875
20876
20877
20878
20879
20880
20881
20882
20883
20884
20885
20886
20887
20888
20889
20890
20891
20892
20893
20894
20895
20896
20897
20898
20899
20900
20901
20902
20903
20904
20905
20906
20907
20908
20909
20910
20911
20912
20913
20914
20915
20916
20917
20918
20919
20920
20921
20922
20923
20924
20925
20926
20927
20928
20929
20930
20931
20932
20933
20934
20935
20936
20937
20938
20939
20940
20941
20942
20943
20944
20945
20946
20947
20948
20949
20950
20951
20952
20953
20954
20955
20956
20957
20958
20959
20960
20961
20962
20963
20964
20965
20966
20967
20968
20969
20970
20971
20972
20973
20974
20975
20976
20977
20978
20979
20980
20981
20982
20983
20984
20985
20986
20987
20988
20989
20990
20991
20992
20993
20994
20995
20996
20997
20998
20999
21000
21001
21002
21003
21004
21005
21006
21007
21008
21009
21010
21011
21012
21013
21014
21015
21016
21017
21018
21019
21020
21021
21022
21023
21024
21025
21026
21027
21028
21029
21030
21031
21032
21033
21034
21035
21036
21037
21038
21039
21040
21041
21042
21043
21044
21045
21046
21047
21048
21049
21050
21051
21052
21053
21054
21055
21056
21057
21058
21059
21060
21061
21062
21063
21064
21065
21066
21067
21068
21069
21070
21071
21072
21073
21074
21075
21076
21077
21078
21079
21080
21081
21082
21083
21084
21085
21086
21087
21088
21089
21090
21091
21092
21093
21094
21095
21096
21097
21098
21099
21100
21101
21102
21103
21104
21105
21106
21107
21108
21109
21110
21111
21112
21113
21114
21115
21116
21117
21118
21119
21120
21121
21122
21123
21124
21125
21126
21127
21128
21129
21130
21131
21132
21133
21134
21135
21136
21137
21138
21139
21140
21141
21142
21143
21144
21145
21146
21147
21148
21149
21150
21151
21152
21153
21154
21155
21156
21157
21158
21159
21160
21161
21162
21163
21164
21165
21166
21167
21168
21169
21170
21171
21172
21173
21174
21175
21176
21177
21178
21179
21180
21181
21182
21183
21184
21185
21186
21187
21188
21189
21190
21191
21192
21193
21194
21195
21196
21197
21198
21199
21200
21201
21202
21203
21204
21205
21206
21207
21208
21209
21210
21211
21212
21213
21214
21215
21216
21217
21218
21219
21220
21221
21222
21223
21224
21225
21226
21227
21228
21229
21230
21231
21232
21233
21234
21235
21236
21237
21238
21239
21240
21241
21242
21243
21244
21245
21246
21247
21248
21249
21250
21251
21252
21253
21254
21255
21256
21257
21258
21259
21260
21261
21262
21263
21264
21265
21266
21267
21268
21269
21270
21271
21272
21273
21274
21275
21276
21277
21278
21279
21280
21281
21282
21283
21284
21285
21286
21287
21288
21289
21290
21291
21292
21293
21294
21295
21296
21297
21298
21299
21300
21301
21302
21303
21304
21305
21306
21307
21308
21309
21310
21311
21312
21313
21314
21315
21316
21317
21318
21319
21320
21321
21322
21323
21324
21325
21326
21327
21328
21329
21330
21331
21332
21333
21334
21335
21336
21337
21338
21339
21340
21341
21342
21343
21344
21345
21346
21347
21348
21349
21350
21351
21352
21353
21354
21355
21356
21357
21358
21359
21360
21361
21362
21363
21364
21365
21366
21367
21368
21369
21370
21371
21372
21373
21374
21375
21376
21377
21378
21379
21380
21381
21382
21383
21384
21385
21386
21387
21388
21389
21390
21391
21392
21393
21394
21395
21396
21397
21398
21399
21400
21401
21402
21403
21404
21405
21406
21407
21408
21409
21410
21411
21412
21413
21414
21415
21416
21417
21418
21419
21420
21421
21422
21423
21424
21425
21426
21427
21428
21429
21430
21431
21432
21433
21434
21435
21436
21437
21438
21439
21440
21441
21442
21443
21444
21445
21446
21447
21448
21449
21450
21451
21452
21453
21454
21455
21456
21457
21458
21459
21460
21461
21462
21463
21464
21465
21466
21467
21468
21469
21470
21471
21472
21473
21474
21475
21476
21477
21478
21479
21480
21481
21482
21483
21484
21485
21486
21487
21488
21489
21490
21491
21492
21493
21494
21495
21496
21497
21498
21499
21500
21501
21502
21503
21504
21505
21506
21507
21508
21509
21510
21511
21512
21513
21514
21515
21516
21517
21518
21519
21520
21521
21522
21523
21524
21525
21526
21527
21528
21529
21530
21531
21532
21533
21534
21535
21536
21537
21538
21539
21540
21541
21542
21543
21544
21545
21546
21547
21548
21549
21550
21551
21552
21553
21554
21555
21556
21557
21558
21559
21560
21561
21562
21563
21564
21565
21566
21567
21568
21569
21570
21571
21572
21573
21574
21575
21576
21577
21578
21579
21580
21581
21582
21583
21584
21585
21586
21587
21588
21589
21590
21591
21592
21593
21594
21595
21596
21597
21598
21599
21600
21601
21602
21603
21604
21605
21606
21607
21608
21609
21610
21611
21612
21613
21614
21615
21616
21617
21618
21619
21620
21621
21622
21623
21624
21625
21626
21627
21628
21629
21630
21631
21632
21633
21634
21635
21636
21637
21638
21639
21640
21641
21642
21643
21644
21645
21646
21647
21648
21649
21650
21651
21652
21653
21654
21655
21656
21657
21658
21659
21660
21661
21662
21663
21664
21665
21666
21667
21668
21669
21670
21671
21672
21673
21674
21675
21676
21677
21678
21679
21680
21681
21682
21683
21684
21685
21686
21687
21688
21689
21690
21691
21692
21693
21694
21695
21696
21697
21698
21699
21700
21701
21702
21703
21704
21705
21706
21707
21708
21709
21710
21711
21712
21713
21714
21715
21716
21717
21718
21719
21720
21721
21722
21723
21724
21725
21726
21727
21728
21729
21730
21731
21732
21733
21734
21735
21736
21737
21738
21739
21740
21741
21742
21743
21744
21745
21746
21747
21748
21749
21750
21751
21752
21753
21754
21755
21756
21757
21758
21759
21760
21761
21762
21763
21764
21765
21766
21767
21768
21769
21770
21771
21772
21773
21774
21775
21776
21777
21778
21779
21780
21781
21782
21783
21784
21785
21786
21787
21788
21789
21790
21791
21792
21793
21794
21795
21796
21797
21798
21799
21800
21801
21802
21803
21804
21805
21806
21807
21808
21809
21810
21811
21812
21813
21814
21815
21816
21817
21818
21819
21820
21821
21822
21823
21824
21825
21826
21827
21828
21829
21830
21831
21832
21833
21834
21835
21836
21837
21838
21839
21840
21841
21842
21843
21844
21845
21846
21847
21848
21849
21850
21851
21852
21853
21854
21855
21856
21857
21858
21859
21860
21861
21862
21863
21864
21865
21866
21867
21868
21869
21870
21871
21872
21873
21874
21875
21876
21877
21878
21879
21880
21881
21882
21883
21884
21885
21886
21887
21888
21889
21890
21891
21892
21893
21894
21895
21896
21897
21898
21899
21900
21901
21902
21903
21904
21905
21906
21907
21908
21909
21910
21911
21912
21913
21914
21915
21916
21917
21918
21919
21920
21921
21922
21923
21924
21925
21926
21927
21928
21929
21930
21931
21932
21933
21934
21935
21936
21937
21938
21939
21940
21941
21942
21943
21944
21945
21946
21947
21948
21949
21950
21951
21952
21953
21954
21955
21956
21957
21958
21959
21960
21961
21962
21963
21964
21965
21966
21967
21968
21969
21970
21971
21972
21973
21974
21975
21976
21977
21978
21979
21980
21981
21982
21983
21984
21985
21986
21987
21988
21989
21990
21991
21992
21993
21994
21995
21996
21997
21998
21999
22000
22001
22002
22003
22004
22005
22006
22007
22008
22009
22010
22011
22012
22013
22014
22015
22016
22017
22018
22019
22020
22021
22022
22023
22024
22025
22026
22027
22028
22029
22030
22031
22032
22033
22034
22035
22036
22037
22038
22039
22040
22041
22042
22043
22044
22045
22046
22047
22048
22049
22050
22051
22052
22053
22054
22055
22056
22057
22058
22059
22060
22061
22062
22063
22064
22065
22066
22067
22068
22069
22070
22071
22072
22073
22074
22075
22076
22077
22078
22079
22080
22081
22082
22083
22084
22085
22086
22087
22088
22089
22090
22091
22092
22093
22094
22095
22096
22097
22098
22099
22100
22101
22102
22103
22104
22105
22106
22107
22108
22109
22110
22111
22112
22113
22114
22115
22116
22117
22118
22119
22120
22121
22122
22123
22124
22125
22126
22127
22128
22129
22130
22131
22132
22133
22134
22135
22136
22137
22138
22139
22140
22141
22142
22143
22144
22145
22146
22147
22148
22149
22150
22151
22152
22153
22154
22155
22156
22157
22158
22159
22160
22161
22162
22163
22164
22165
22166
22167
22168
22169
22170
22171
22172
22173
22174
22175
22176
22177
22178
22179
22180
22181
22182
22183
22184
22185
22186
22187
22188
22189
22190
22191
22192
22193
22194
22195
22196
22197
22198
22199
22200
22201
22202
22203
22204
22205
22206
22207
22208
22209
22210
22211
22212
22213
22214
22215
22216
22217
22218
22219
22220
22221
22222
22223
22224
22225
22226
22227
22228
22229
22230
22231
22232
22233
22234
22235
22236
22237
22238
22239
22240
22241
22242
22243
22244
22245
22246
22247
22248
22249
22250
22251
22252
22253
22254
22255
22256
22257
22258
22259
22260
22261
22262
22263
22264
22265
22266
22267
22268
22269
22270
22271
22272
22273
22274
22275
22276
22277
22278
22279
22280
22281
22282
22283
22284
22285
22286
22287
22288
22289
22290
22291
22292
22293
22294
22295
22296
22297
22298
22299
22300
22301
22302
22303
22304
22305
22306
22307
22308
22309
22310
22311
22312
22313
22314
22315
22316
22317
22318
22319
22320
22321
22322
22323
22324
22325
22326
22327
22328
22329
22330
22331
22332
22333
22334
22335
22336
22337
22338
22339
22340
22341
22342
22343
22344
22345
22346
22347
22348
22349
22350
22351
22352
22353
22354
22355
22356
22357
22358
22359
22360
22361
22362
22363
22364
22365
22366
22367
22368
22369
22370
22371
22372
22373
22374
22375
22376
22377
22378
22379
22380
22381
22382
22383
22384
22385
22386
22387
22388
22389
22390
22391
22392
22393
22394
22395
22396
22397
22398
22399
22400
22401
22402
22403
22404
22405
22406
22407
22408
22409
22410
22411
22412
22413
22414
22415
22416
22417
22418
22419
22420
22421
22422
22423
22424
22425
22426
22427
22428
22429
22430
22431
22432
22433
22434
22435
22436
22437
22438
22439
22440
22441
22442
22443
22444
22445
22446
22447
22448
22449
22450
22451
22452
22453
22454
22455
22456
22457
22458
22459
22460
22461
22462
22463
22464
22465
22466
22467
22468
22469
22470
22471
22472
22473
22474
22475
22476
22477
22478
22479
22480
22481
22482
22483
22484
22485
22486
22487
22488
22489
22490
22491
22492
22493
22494
22495
22496
22497
22498
22499
22500
22501
22502
22503
22504
22505
22506
22507
22508
22509
22510
22511
22512
22513
22514
22515
22516
22517
22518
22519
22520
22521
22522
22523
22524
22525
22526
22527
22528
22529
22530
22531
22532
22533
22534
22535
22536
22537
22538
22539
22540
22541
22542
22543
22544
22545
22546
22547
22548
22549
22550
22551
22552
22553
22554
22555
22556
22557
22558
22559
22560
22561
22562
22563
22564
22565
22566
22567
22568
22569
22570
22571
22572
22573
22574
22575
22576
22577
22578
22579
22580
22581
22582
22583
22584
22585
22586
22587
22588
22589
22590
22591
22592
22593
22594
22595
22596
22597
22598
22599
22600
22601
22602
22603
22604
22605
22606
22607
22608
22609
22610
22611
22612
22613
22614
22615
22616
22617
22618
22619
22620
22621
22622
22623
22624
22625
22626
22627
22628
22629
22630
22631
22632
22633
22634
22635
22636
22637
22638
22639
22640
22641
22642
22643
22644
22645
22646
22647
22648
22649
22650
22651
22652
22653
22654
22655
22656
22657
22658
22659
22660
22661
22662
22663
22664
22665
22666
22667
22668
22669
22670
22671
22672
22673
22674
22675
22676
22677
22678
22679
22680
22681
22682
22683
22684
22685
22686
22687
22688
22689
22690
22691
22692
22693
22694
22695
22696
22697
22698
22699
22700
22701
22702
22703
22704
22705
22706
22707
22708
22709
22710
22711
22712
22713
22714
22715
22716
22717
22718
22719
22720
22721
22722
22723
22724
22725
22726
22727
22728
22729
22730
22731
22732
22733
22734
22735
22736
22737
22738
22739
22740
22741
22742
22743
22744
22745
22746
22747
22748
22749
22750
22751
22752
22753
22754
22755
22756
22757
22758
22759
22760
22761
22762
22763
22764
22765
22766
22767
22768
22769
22770
22771
22772
22773
22774
22775
22776
22777
22778
22779
22780
22781
22782
22783
22784
22785
22786
22787
22788
22789
22790
22791
22792
22793
22794
22795
22796
22797
22798
22799
22800
22801
22802
22803
22804
22805
22806
22807
22808
22809
22810
22811
22812
22813
22814
22815
22816
22817
22818
22819
22820
22821
22822
22823
22824
22825
22826
22827
22828
22829
22830
22831
22832
22833
22834
22835
22836
22837
22838
22839
22840
22841
22842
22843
22844
22845
22846
22847
22848
22849
22850
22851
22852
22853
22854
22855
22856
22857
22858
22859
22860
22861
22862
22863
22864
22865
22866
22867
22868
22869
22870
22871
22872
22873
22874
22875
22876
22877
22878
22879
22880
22881
22882
22883
22884
22885
22886
22887
22888
22889
22890
22891
22892
22893
22894
22895
22896
22897
22898
22899
22900
22901
22902
22903
22904
22905
22906
22907
22908
22909
22910
22911
22912
22913
22914
22915
22916
22917
22918
22919
22920
22921
22922
22923
22924
22925
22926
22927
22928
22929
22930
22931
22932
22933
22934
22935
22936
22937
22938
22939
22940
22941
22942
22943
22944
22945
22946
22947
22948
22949
22950
22951
22952
22953
22954
22955
22956
22957
22958
22959
22960
22961
22962
22963
22964
22965
22966
22967
22968
22969
22970
22971
22972
22973
22974
22975
22976
22977
22978
22979
22980
22981
22982
22983
22984
22985
22986
22987
22988
22989
22990
22991
22992
22993
22994
22995
22996
22997
22998
22999
23000
23001
23002
23003
23004
23005
23006
23007
23008
23009
23010
23011
23012
23013
23014
23015
23016
23017
23018
23019
23020
23021
23022
23023
23024
23025
23026
23027
23028
23029
23030
23031
23032
23033
23034
23035
23036
23037
23038
23039
23040
23041
23042
23043
23044
23045
23046
23047
23048
23049
23050
23051
23052
23053
23054
23055
23056
23057
23058
23059
23060
23061
23062
23063
23064
23065
23066
23067
23068
23069
23070
23071
23072
23073
23074
23075
23076
23077
23078
23079
23080
23081
23082
23083
23084
23085
23086
23087
23088
23089
23090
23091
23092
23093
23094
23095
23096
23097
23098
23099
23100
23101
23102
23103
23104
23105
23106
23107
23108
23109
23110
23111
23112
23113
23114
23115
23116
23117
23118
23119
23120
23121
23122
23123
23124
23125
23126
23127
23128
23129
23130
23131
23132
23133
23134
23135
23136
23137
23138
23139
23140
23141
23142
23143
23144
23145
23146
23147
23148
23149
23150
23151
23152
23153
23154
23155
23156
23157
23158
23159
23160
23161
23162
23163
23164
23165
23166
23167
23168
23169
23170
23171
23172
23173
23174
23175
23176
23177
23178
23179
23180
23181
23182
23183
23184
23185
23186
23187
23188
23189
23190
23191
23192
23193
23194
23195
23196
23197
23198
23199
23200
23201
23202
23203
23204
23205
23206
23207
23208
23209
23210
23211
23212
23213
23214
23215
23216
23217
23218
23219
23220
23221
23222
23223
23224
23225
23226
23227
23228
23229
23230
23231
23232
23233
23234
23235
23236
23237
23238
23239
23240
23241
23242
23243
23244
23245
23246
23247
23248
23249
23250
23251
23252
23253
23254
23255
23256
23257
23258
23259
23260
23261
23262
23263
23264
23265
23266
23267
23268
23269
23270
23271
23272
23273
23274
23275
23276
23277
23278
23279
23280
23281
23282
23283
23284
23285
23286
23287
23288
23289
23290
23291
23292
23293
23294
23295
23296
23297
23298
23299
23300
23301
23302
23303
23304
23305
23306
23307
23308
23309
23310
23311
23312
23313
23314
23315
23316
23317
23318
23319
23320
23321
23322
23323
23324
23325
23326
23327
23328
23329
23330
23331
23332
23333
23334
23335
23336
23337
23338
23339
23340
23341
23342
23343
23344
23345
23346
23347
23348
23349
23350
23351
23352
23353
23354
23355
23356
23357
23358
23359
23360
23361
23362
23363
23364
23365
23366
23367
23368
23369
23370
23371
23372
23373
23374
23375
23376
23377
23378
23379
23380
23381
23382
23383
23384
23385
23386
23387
23388
23389
23390
23391
23392
23393
23394
23395
23396
23397
23398
23399
23400
23401
23402
23403
23404
23405
23406
23407
23408
23409
23410
23411
23412
23413
23414
23415
23416
23417
23418
23419
23420
23421
23422
23423
23424
23425
23426
23427
23428
23429
23430
23431
23432
23433
23434
23435
23436
23437
23438
23439
23440
23441
23442
23443
23444
23445
23446
23447
23448
23449
23450
23451
23452
23453
23454
23455
23456
23457
23458
23459
23460
23461
23462
23463
23464
23465
23466
23467
23468
23469
23470
23471
23472
23473
23474
23475
23476
23477
23478
23479
23480
23481
23482
23483
23484
23485
23486
23487
23488
23489
23490
23491
23492
23493
23494
23495
23496
23497
23498
23499
23500
23501
23502
23503
23504
23505
23506
23507
23508
23509
23510
23511
23512
23513
23514
23515
23516
23517
23518
23519
23520
23521
23522
23523
23524
23525
23526
23527
23528
23529
23530
23531
23532
23533
23534
23535
23536
23537
23538
23539
23540
23541
23542
23543
23544
23545
23546
23547
23548
23549
23550
23551
23552
23553
23554
23555
23556
23557
23558
23559
23560
23561
23562
23563
23564
23565
23566
23567
23568
23569
23570
23571
23572
23573
23574
23575
23576
23577
23578
23579
23580
23581
23582
23583
23584
23585
23586
23587
23588
23589
23590
23591
23592
23593
23594
23595
23596
23597
23598
23599
23600
23601
23602
23603
23604
23605
23606
23607
23608
23609
23610
23611
23612
23613
23614
23615
23616
23617
23618
23619
23620
23621
23622
23623
23624
23625
23626
23627
23628
23629
23630
23631
23632
23633
23634
23635
23636
23637
23638
23639
23640
23641
23642
23643
23644
23645
23646
23647
23648
23649
23650
23651
23652
23653
23654
23655
23656
23657
23658
23659
23660
23661
23662
23663
23664
23665
23666
23667
23668
23669
23670
23671
23672
23673
23674
23675
23676
23677
23678
23679
23680
23681
23682
23683
23684
23685
23686
23687
23688
23689
23690
23691
23692
23693
23694
23695
23696
23697
23698
23699
23700
23701
23702
23703
23704
23705
23706
23707
23708
23709
23710
23711
23712
23713
23714
23715
23716
23717
23718
23719
23720
23721
23722
23723
23724
23725
23726
23727
23728
23729
23730
23731
23732
23733
23734
23735
23736
23737
23738
23739
23740
23741
23742
23743
23744
23745
23746
23747
23748
23749
23750
23751
23752
23753
23754
23755
23756
23757
23758
23759
23760
23761
23762
23763
23764
23765
23766
23767
23768
23769
23770
23771
23772
23773
23774
23775
23776
23777
23778
23779
23780
23781
23782
23783
23784
23785
23786
23787
23788
23789
23790
23791
23792
23793
23794
23795
23796
23797
23798
23799
23800
23801
23802
23803
23804
23805
23806
23807
23808
23809
23810
23811
23812
23813
23814
23815
23816
23817
23818
23819
23820
23821
23822
23823
23824
23825
23826
23827
23828
23829
23830
23831
23832
23833
23834
23835
23836
23837
23838
23839
23840
23841
23842
23843
23844
23845
23846
23847
23848
23849
23850
23851
23852
23853
23854
23855
23856
23857
23858
23859
23860
23861
23862
23863
23864
23865
23866
23867
23868
23869
23870
23871
23872
23873
23874
23875
23876
23877
23878
23879
23880
23881
23882
23883
23884
23885
23886
23887
23888
23889
23890
23891
23892
23893
23894
23895
23896
23897
23898
23899
23900
23901
23902
23903
23904
23905
23906
23907
23908
23909
23910
23911
23912
23913
23914
23915
23916
23917
23918
23919
23920
23921
23922
23923
23924
23925
23926
23927
23928
23929
23930
23931
23932
23933
23934
23935
23936
23937
23938
23939
23940
23941
23942
23943
23944
23945
23946
23947
23948
23949
23950
23951
23952
23953
23954
23955
23956
23957
23958
23959
23960
23961
23962
23963
23964
23965
23966
23967
23968
23969
23970
23971
23972
23973
23974
23975
23976
23977
23978
23979
23980
23981
23982
23983
23984
23985
23986
23987
23988
23989
23990
23991
23992
23993
23994
23995
23996
23997
23998
23999
24000
24001
24002
24003
24004
24005
24006
24007
24008
24009
24010
24011
24012
24013
24014
24015
24016
24017
24018
24019
24020
24021
24022
24023
24024
24025
24026
24027
24028
24029
24030
24031
24032
24033
24034
24035
24036
24037
24038
24039
24040
24041
24042
24043
24044
24045
24046
24047
24048
24049
24050
24051
24052
24053
24054
24055
24056
24057
24058
24059
24060
24061
24062
24063
24064
24065
24066
24067
24068
24069
24070
24071
24072
24073
24074
24075
24076
24077
24078
24079
24080
24081
24082
24083
24084
24085
24086
24087
24088
24089
24090
24091
24092
24093
24094
24095
24096
24097
24098
24099
24100
24101
24102
24103
24104
24105
24106
24107
24108
24109
24110
24111
24112
24113
24114
24115
24116
24117
24118
24119
24120
24121
24122
24123
24124
24125
24126
24127
24128
24129
24130
24131
24132
24133
24134
24135
24136
24137
24138
24139
24140
24141
24142
24143
24144
24145
24146
24147
24148
24149
24150
24151
24152
24153
24154
24155
24156
24157
24158
24159
24160
24161
24162
24163
24164
24165
24166
24167
24168
24169
24170
24171
24172
24173
24174
24175
24176
24177
24178
24179
24180
24181
24182
24183
24184
24185
24186
24187
24188
24189
24190
24191
24192
24193
24194
24195
24196
24197
24198
24199
24200
24201
24202
24203
24204
24205
24206
24207
24208
24209
24210
24211
24212
24213
24214
24215
24216
24217
24218
24219
24220
24221
24222
24223
24224
24225
24226
24227
24228
24229
24230
24231
24232
24233
24234
24235
24236
24237
24238
24239
24240
24241
24242
24243
24244
24245
24246
24247
24248
24249
24250
24251
24252
24253
24254
24255
24256
24257
24258
24259
24260
24261
24262
24263
24264
24265
24266
24267
24268
24269
24270
24271
24272
24273
24274
24275
24276
24277
24278
24279
24280
24281
24282
24283
24284
24285
24286
24287
24288
24289
24290
24291
24292
24293
24294
24295
24296
24297
24298
24299
24300
24301
24302
24303
24304
24305
24306
24307
24308
24309
24310
24311
24312
24313
24314
24315
24316
24317
24318
24319
24320
24321
24322
24323
24324
24325
24326
24327
24328
24329
24330
24331
24332
24333
24334
24335
24336
24337
24338
24339
24340
24341
24342
24343
24344
24345
24346
24347
24348
24349
24350
24351
24352
24353
24354
24355
24356
24357
24358
24359
24360
24361
24362
24363
24364
24365
24366
24367
24368
24369
24370
24371
24372
24373
24374
24375
24376
24377
24378
24379
24380
24381
24382
24383
24384
24385
24386
24387
24388
24389
24390
24391
24392
24393
24394
24395
24396
24397
24398
24399
24400
24401
24402
24403
24404
24405
24406
24407
24408
24409
24410
24411
24412
24413
24414
24415
24416
24417
24418
24419
24420
24421
24422
24423
24424
24425
24426
24427
24428
24429
24430
24431
24432
24433
24434
24435
24436
24437
24438
24439
24440
24441
24442
24443
24444
24445
24446
24447
24448
24449
24450
24451
24452
24453
24454
24455
24456
24457
24458
24459
24460
24461
24462
24463
24464
24465
24466
24467
24468
24469
24470
24471
24472
24473
24474
24475
24476
24477
24478
24479
24480
24481
24482
24483
24484
24485
24486
24487
24488
24489
24490
24491
24492
24493
24494
24495
24496
24497
24498
24499
24500
24501
24502
24503
24504
24505
24506
24507
24508
24509
24510
24511
24512
24513
24514
24515
24516
24517
24518
24519
24520
24521
24522
24523
24524
24525
24526
24527
24528
24529
24530
24531
24532
24533
24534
24535
24536
24537
24538
24539
24540
24541
24542
24543
24544
24545
24546
24547
24548
24549
24550
24551
24552
24553
24554
24555
24556
24557
24558
24559
24560
24561
24562
24563
24564
24565
24566
24567
24568
24569
24570
24571
24572
24573
24574
24575
24576
24577
24578
24579
24580
24581
24582
24583
24584
24585
24586
24587
24588
24589
24590
24591
24592
24593
24594
24595
24596
24597
24598
24599
24600
24601
24602
24603
24604
24605
24606
24607
24608
24609
24610
24611
24612
24613
24614
24615
24616
24617
24618
24619
24620
24621
24622
24623
24624
24625
24626
24627
24628
24629
24630
24631
24632
24633
24634
24635
24636
24637
24638
24639
24640
24641
24642
24643
24644
24645
24646
24647
24648
24649
24650
24651
24652
24653
24654
24655
24656
24657
24658
24659
24660
24661
24662
24663
24664
24665
24666
24667
24668
24669
24670
24671
24672
24673
24674
24675
24676
24677
24678
24679
24680
24681
24682
24683
24684
24685
24686
24687
24688
24689
24690
24691
24692
24693
24694
24695
24696
24697
24698
24699
24700
24701
24702
24703
24704
24705
24706
24707
24708
24709
24710
24711
24712
24713
24714
24715
24716
24717
24718
24719
24720
24721
24722
24723
24724
24725
24726
24727
24728
24729
24730
24731
24732
24733
24734
24735
24736
24737
24738
24739
24740
24741
24742
24743
24744
24745
24746
24747
24748
24749
24750
24751
24752
24753
24754
24755
24756
24757
24758
24759
24760
24761
24762
24763
24764
24765
24766
24767
24768
24769
24770
24771
24772
24773
24774
24775
24776
24777
24778
24779
24780
24781
24782
24783
24784
24785
24786
24787
24788
24789
24790
24791
24792
24793
24794
24795
24796
24797
24798
24799
24800
24801
24802
24803
24804
24805
24806
24807
24808
24809
24810
24811
24812
24813
24814
24815
24816
24817
24818
24819
24820
24821
24822
24823
24824
24825
24826
24827
24828
24829
24830
24831
24832
24833
24834
24835
24836
24837
24838
24839
24840
24841
24842
24843
24844
24845
24846
24847
24848
24849
24850
24851
24852
24853
24854
24855
24856
24857
24858
24859
24860
24861
24862
24863
24864
24865
24866
24867
24868
24869
24870
24871
24872
24873
24874
24875
24876
24877
24878
24879
24880
24881
24882
24883
24884
24885
24886
24887
24888
24889
24890
24891
24892
24893
24894
24895
24896
24897
24898
24899
24900
24901
24902
24903
24904
24905
24906
24907
24908
24909
24910
24911
24912
24913
24914
24915
24916
24917
24918
24919
24920
24921
24922
24923
24924
24925
24926
24927
24928
24929
24930
24931
24932
24933
24934
24935
24936
24937
24938
24939
24940
24941
24942
24943
24944
24945
24946
24947
24948
24949
24950
24951
24952
24953
24954
24955
24956
24957
24958
24959
24960
24961
24962
24963
24964
24965
24966
24967
24968
24969
24970
24971
24972
24973
24974
24975
24976
24977
24978
24979
24980
24981
24982
24983
24984
24985
24986
24987
24988
24989
24990
24991
24992
24993
24994
24995
24996
24997
24998
24999
25000
25001
25002
25003
25004
25005
25006
25007
25008
25009
25010
25011
25012
25013
25014
25015
25016
25017
25018
25019
25020
25021
25022
25023
25024
25025
25026
25027
25028
25029
25030
25031
25032
25033
25034
25035
25036
25037
25038
25039
25040
25041
25042
25043
25044
25045
25046
25047
25048
25049
25050
25051
25052
25053
25054
25055
25056
25057
25058
25059
25060
25061
25062
25063
25064
25065
25066
25067
25068
25069
25070
25071
25072
25073
25074
25075
25076
25077
25078
25079
25080
25081
25082
25083
25084
25085
25086
25087
25088
25089
25090
25091
25092
25093
25094
25095
25096
25097
25098
25099
25100
25101
25102
25103
25104
25105
25106
25107
25108
25109
25110
25111
25112
25113
25114
25115
25116
25117
25118
25119
25120
25121
25122
25123
25124
25125
25126
25127
25128
25129
25130
25131
25132
25133
25134
25135
25136
25137
25138
25139
25140
25141
25142
25143
25144
25145
25146
25147
25148
25149
25150
25151
25152
25153
25154
25155
25156
25157
25158
25159
25160
25161
25162
25163
25164
25165
25166
25167
25168
25169
25170
25171
25172
25173
25174
25175
25176
25177
25178
25179
25180
25181
25182
25183
25184
25185
25186
25187
25188
25189
25190
25191
25192
25193
25194
25195
25196
25197
25198
25199
25200
25201
25202
25203
25204
25205
25206
25207
25208
25209
25210
25211
25212
25213
25214
25215
25216
25217
25218
25219
25220
25221
25222
25223
25224
25225
25226
25227
25228
25229
25230
25231
25232
25233
25234
25235
25236
25237
25238
25239
25240
25241
25242
25243
25244
25245
25246
25247
25248
25249
25250
25251
25252
25253
25254
25255
25256
25257
25258
25259
25260
25261
25262
25263
25264
25265
25266
25267
25268
25269
25270
25271
25272
25273
25274
25275
25276
25277
25278
25279
25280
25281
25282
25283
25284
25285
25286
25287
25288
25289
25290
25291
25292
25293
25294
25295
25296
25297
25298
25299
25300
25301
25302
25303
25304
25305
25306
25307
25308
25309
25310
25311
25312
25313
25314
25315
25316
25317
25318
25319
25320
25321
25322
25323
25324
25325
25326
25327
25328
25329
25330
25331
25332
25333
25334
25335
25336
25337
25338
25339
25340
25341
25342
25343
25344
25345
25346
25347
25348
25349
25350
25351
25352
25353
25354
25355
25356
25357
25358
25359
25360
25361
25362
25363
25364
25365
25366
25367
25368
25369
25370
25371
25372
25373
25374
25375
25376
25377
25378
25379
25380
25381
25382
25383
25384
25385
25386
25387
25388
25389
25390
25391
25392
25393
25394
25395
25396
25397
25398
25399
25400
25401
25402
25403
25404
25405
25406
25407
25408
25409
25410
25411
25412
25413
25414
25415
25416
25417
25418
25419
25420
25421
25422
25423
25424
25425
25426
25427
25428
25429
25430
25431
25432
25433
25434
25435
25436
25437
25438
25439
25440
25441
25442
25443
25444
25445
25446
25447
25448
25449
25450
25451
25452
25453
25454
25455
25456
25457
25458
25459
25460
25461
25462
25463
25464
25465
25466
25467
25468
25469
25470
25471
25472
25473
25474
25475
25476
25477
25478
25479
25480
25481
25482
25483
25484
25485
25486
25487
25488
25489
25490
25491
25492
25493
25494
25495
25496
25497
25498
25499
25500
25501
25502
25503
25504
25505
25506
25507
25508
25509
25510
25511
25512
25513
25514
25515
25516
25517
25518
25519
25520
25521
25522
25523
25524
25525
25526
25527
25528
25529
25530
25531
25532
25533
25534
25535
25536
25537
25538
25539
25540
25541
25542
25543
25544
25545
25546
25547
25548
25549
25550
25551
25552
25553
25554
25555
25556
25557
25558
25559
25560
25561
25562
25563
25564
25565
25566
25567
25568
25569
25570
25571
25572
25573
25574
25575
25576
25577
25578
25579
25580
25581
25582
25583
25584
25585
25586
25587
25588
25589
25590
25591
25592
25593
25594
25595
25596
25597
25598
25599
25600
25601
25602
25603
25604
25605
25606
25607
25608
25609
25610
25611
25612
25613
25614
25615
25616
25617
25618
25619
25620
25621
25622
25623
25624
25625
25626
25627
25628
25629
25630
25631
25632
25633
25634
25635
25636
25637
25638
25639
25640
25641
25642
25643
25644
25645
25646
25647
25648
25649
25650
25651
25652
25653
25654
25655
25656
25657
25658
25659
25660
25661
25662
25663
25664
25665
25666
25667
25668
25669
25670
25671
25672
25673
25674
25675
25676
25677
25678
25679
25680
25681
25682
25683
25684
25685
25686
25687
25688
25689
25690
25691
25692
25693
25694
25695
25696
25697
25698
25699
25700
25701
25702
25703
25704
25705
25706
25707
25708
25709
25710
25711
25712
25713
25714
25715
25716
25717
25718
25719
25720
25721
25722
25723
25724
25725
25726
25727
25728
25729
25730
25731
25732
25733
25734
25735
25736
25737
25738
25739
25740
25741
25742
25743
25744
25745
25746
25747
25748
25749
25750
25751
25752
25753
25754
25755
25756
25757
25758
25759
25760
25761
25762
25763
25764
25765
25766
25767
25768
25769
25770
25771
25772
25773
25774
25775
25776
25777
25778
25779
25780
25781
25782
25783
25784
25785
25786
25787
25788
25789
25790
25791
25792
25793
25794
25795
25796
25797
25798
25799
25800
25801
25802
25803
25804
25805
25806
25807
25808
25809
25810
25811
25812
25813
25814
25815
25816
25817
25818
25819
25820
25821
25822
25823
25824
25825
25826
25827
25828
25829
25830
25831
25832
25833
25834
25835
25836
25837
25838
25839
25840
25841
25842
25843
25844
25845
25846
25847
25848
25849
25850
25851
25852
25853
25854
25855
25856
25857
25858
25859
25860
25861
25862
25863
25864
25865
25866
25867
25868
25869
25870
25871
25872
25873
25874
25875
25876
25877
25878
25879
25880
25881
25882
25883
25884
25885
25886
25887
25888
25889
25890
25891
25892
25893
25894
25895
25896
25897
25898
25899
25900
25901
25902
25903
25904
25905
25906
25907
25908
25909
25910
25911
25912
25913
25914
25915
25916
25917
25918
25919
25920
25921
25922
25923
25924
25925
25926
25927
25928
25929
25930
25931
25932
25933
25934
25935
25936
25937
25938
25939
25940
25941
25942
25943
25944
25945
25946
25947
25948
25949
25950
25951
25952
25953
25954
25955
25956
25957
25958
25959
25960
25961
25962
25963
25964
25965
25966
25967
25968
25969
25970
25971
25972
25973
25974
25975
25976
25977
25978
25979
25980
25981
25982
25983
25984
25985
25986
25987
25988
25989
25990
25991
25992
25993
25994
25995
25996
25997
25998
25999
26000
26001
26002
26003
26004
26005
26006
26007
26008
26009
26010
26011
26012
26013
26014
26015
26016
26017
26018
26019
26020
26021
26022
26023
26024
26025
26026
26027
26028
26029
26030
26031
26032
26033
26034
26035
26036
26037
26038
26039
26040
26041
26042
26043
26044
26045
26046
26047
26048
26049
26050
26051
26052
26053
26054
26055
26056
26057
26058
26059
26060
26061
26062
26063
26064
26065
26066
26067
26068
26069
26070
26071
26072
26073
26074
26075
26076
26077
26078
26079
26080
26081
26082
26083
26084
26085
26086
26087
26088
26089
26090
26091
26092
26093
26094
26095
26096
26097
26098
26099
26100
26101
26102
26103
26104
26105
26106
26107
26108
26109
26110
26111
26112
26113
26114
26115
26116
26117
26118
26119
26120
26121
26122
26123
26124
26125
26126
26127
26128
26129
26130
26131
26132
26133
26134
26135
26136
26137
26138
26139
26140
26141
26142
26143
26144
26145
26146
26147
26148
26149
26150
26151
26152
26153
26154
26155
26156
26157
26158
26159
26160
26161
26162
26163
26164
26165
26166
26167
26168
26169
26170
26171
26172
26173
26174
26175
26176
26177
26178
26179
26180
26181
26182
26183
26184
26185
26186
26187
26188
26189
26190
26191
26192
26193
26194
26195
26196
26197
26198
26199
26200
26201
26202
26203
26204
26205
26206
26207
26208
26209
26210
26211
26212
26213
26214
26215
26216
26217
26218
26219
26220
26221
26222
26223
26224
26225
26226
26227
26228
26229
26230
26231
26232
26233
26234
26235
26236
26237
26238
26239
26240
26241
26242
26243
26244
26245
26246
26247
26248
26249
26250
26251
26252
26253
26254
26255
26256
26257
26258
26259
26260
26261
26262
26263
26264
26265
26266
26267
26268
26269
26270
26271
26272
26273
26274
26275
26276
26277
26278
26279
26280
26281
26282
26283
26284
26285
26286
26287
26288
26289
26290
26291
26292
26293
26294
26295
26296
26297
26298
26299
26300
26301
26302
26303
26304
26305
26306
26307
26308
26309
26310
26311
26312
26313
26314
26315
26316
26317
26318
26319
26320
26321
26322
26323
26324
26325
26326
26327
26328
26329
26330
26331
26332
26333
26334
26335
26336
26337
26338
26339
26340
26341
26342
26343
26344
26345
26346
26347
26348
26349
26350
26351
26352
26353
26354
26355
26356
26357
26358
26359
26360
26361
26362
26363
26364
26365
26366
26367
26368
26369
26370
26371
26372
26373
26374
26375
26376
26377
26378
26379
26380
26381
26382
26383
26384
26385
26386
26387
26388
26389
26390
26391
26392
26393
26394
26395
26396
26397
26398
26399
26400
26401
26402
26403
26404
26405
26406
26407
26408
26409
26410
26411
26412
26413
26414
26415
26416
26417
26418
26419
26420
26421
26422
26423
26424
26425
26426
26427
26428
26429
26430
26431
26432
26433
26434
26435
26436
26437
26438
26439
26440
26441
26442
26443
26444
26445
26446
26447
26448
26449
26450
26451
26452
26453
26454
26455
26456
26457
26458
26459
26460
26461
26462
26463
26464
26465
26466
26467
26468
26469
26470
26471
26472
26473
26474
26475
26476
26477
26478
26479
26480
26481
26482
26483
26484
26485
26486
26487
26488
26489
26490
26491
26492
26493
26494
26495
26496
26497
26498
26499
26500
26501
26502
26503
26504
26505
26506
26507
26508
26509
26510
26511
26512
26513
26514
26515
26516
26517
26518
26519
26520
26521
26522
26523
26524
26525
26526
26527
26528
26529
26530
26531
26532
26533
26534
26535
26536
26537
26538
26539
26540
26541
26542
26543
26544
26545
26546
26547
26548
26549
26550
26551
26552
26553
26554
26555
26556
26557
26558
26559
26560
26561
26562
26563
26564
26565
26566
26567
26568
26569
26570
26571
26572
26573
26574
26575
26576
26577
26578
26579
26580
26581
26582
26583
26584
26585
26586
26587
26588
26589
26590
26591
26592
26593
26594
26595
26596
26597
26598
26599
26600
26601
26602
26603
26604
26605
26606
26607
26608
26609
26610
26611
26612
26613
26614
26615
26616
26617
26618
26619
26620
26621
26622
26623
26624
26625
26626
26627
26628
26629
26630
26631
26632
26633
26634
26635
26636
26637
26638
26639
26640
26641
26642
26643
26644
26645
26646
26647
26648
26649
26650
26651
26652
26653
26654
26655
26656
26657
26658
26659
26660
26661
26662
26663
26664
26665
26666
26667
26668
26669
26670
26671
26672
26673
26674
26675
26676
26677
26678
26679
26680
26681
26682
26683
26684
26685
26686
26687
26688
26689
26690
26691
26692
26693
26694
26695
26696
26697
26698
26699
26700
26701
26702
26703
26704
26705
26706
26707
26708
26709
26710
26711
26712
26713
26714
26715
26716
26717
26718
26719
26720
26721
26722
26723
26724
26725
26726
26727
26728
26729
26730
26731
26732
26733
26734
26735
26736
26737
26738
26739
26740
26741
26742
26743
26744
26745
26746
26747
26748
26749
26750
26751
26752
26753
26754
26755
26756
26757
26758
26759
26760
26761
26762
26763
26764
26765
26766
26767
26768
26769
26770
26771
26772
26773
26774
26775
26776
26777
26778
26779
26780
26781
26782
26783
26784
26785
26786
26787
26788
26789
26790
26791
26792
26793
26794
26795
26796
26797
26798
26799
26800
26801
26802
26803
26804
26805
26806
26807
26808
26809
26810
26811
26812
26813
26814
26815
26816
26817
26818
26819
26820
26821
26822
26823
26824
26825
26826
26827
26828
26829
26830
26831
26832
26833
26834
26835
26836
26837
26838
26839
26840
26841
26842
26843
26844
26845
26846
26847
26848
26849
26850
26851
26852
26853
26854
26855
26856
26857
26858
26859
26860
26861
26862
26863
26864
26865
26866
26867
26868
26869
26870
26871
26872
26873
26874
26875
26876
26877
26878
26879
26880
26881
26882
26883
26884
26885
26886
26887
26888
26889
26890
26891
26892
26893
26894
26895
26896
26897
26898
26899
26900
26901
26902
26903
26904
26905
26906
26907
26908
26909
26910
26911
26912
26913
26914
26915
26916
26917
26918
26919
26920
26921
26922
26923
26924
26925
26926
26927
26928
26929
26930
26931
26932
26933
26934
26935
26936
26937
26938
26939
26940
26941
26942
26943
26944
26945
26946
26947
26948
26949
26950
26951
26952
26953
26954
26955
26956
26957
26958
26959
26960
26961
26962
26963
26964
26965
26966
26967
26968
26969
26970
26971
26972
26973
26974
26975
26976
26977
26978
26979
26980
26981
26982
26983
26984
26985
26986
26987
26988
26989
26990
26991
26992
26993
26994
26995
26996
26997
26998
26999
27000
27001
27002
27003
27004
27005
27006
27007
27008
27009
27010
27011
27012
27013
27014
27015
27016
27017
27018
27019
27020
27021
27022
27023
27024
27025
27026
27027
27028
27029
27030
27031
27032
27033
27034
27035
27036
27037
27038
27039
27040
27041
27042
27043
27044
27045
27046
27047
27048
27049
27050
27051
27052
27053
27054
27055
27056
27057
27058
27059
27060
27061
27062
27063
27064
27065
27066
27067
27068
27069
27070
27071
27072
27073
27074
27075
27076
27077
27078
27079
27080
27081
27082
27083
27084
27085
27086
27087
27088
27089
27090
27091
27092
27093
27094
27095
27096
27097
27098
27099
27100
27101
27102
27103
27104
27105
27106
27107
27108
27109
27110
27111
27112
27113
27114
27115
27116
27117
27118
27119
27120
27121
27122
27123
27124
27125
27126
27127
27128
27129
27130
27131
27132
27133
27134
27135
27136
27137
27138
27139
27140
27141
27142
27143
27144
27145
27146
27147
27148
27149
27150
27151
27152
27153
27154
27155
27156
27157
27158
27159
27160
27161
27162
27163
27164
27165
27166
27167
27168
27169
27170
27171
27172
27173
27174
27175
27176
27177
27178
27179
27180
27181
27182
27183
27184
27185
27186
27187
27188
27189
27190
27191
27192
27193
27194
27195
27196
27197
27198
27199
27200
27201
27202
27203
27204
27205
27206
27207
27208
27209
27210
27211
27212
27213
27214
27215
27216
27217
27218
27219
27220
27221
27222
27223
27224
27225
27226
27227
27228
27229
27230
27231
27232
27233
27234
27235
27236
27237
27238
27239
27240
27241
27242
27243
27244
27245
27246
27247
27248
27249
27250
27251
27252
27253
27254
27255
27256
27257
27258
27259
27260
27261
27262
27263
27264
27265
27266
27267
27268
27269
27270
27271
27272
27273
27274
27275
27276
27277
27278
27279
27280
27281
27282
27283
27284
27285
27286
27287
27288
27289
27290
27291
27292
27293
27294
27295
27296
27297
27298
27299
27300
27301
27302
27303
27304
27305
27306
27307
27308
27309
27310
27311
27312
27313
27314
27315
27316
27317
27318
27319
27320
27321
27322
27323
27324
27325
27326
27327
27328
27329
27330
27331
27332
27333
27334
27335
27336
27337
27338
27339
27340
27341
27342
27343
27344
27345
27346
27347
27348
27349
27350
27351
27352
27353
27354
27355
27356
27357
27358
27359
27360
27361
27362
27363
27364
27365
27366
27367
27368
27369
27370
27371
27372
27373
27374
27375
27376
27377
27378
27379
27380
27381
27382
27383
27384
27385
27386
27387
27388
27389
27390
27391
27392
27393
27394
27395
27396
27397
27398
27399
27400
27401
27402
27403
27404
27405
27406
27407
27408
27409
27410
27411
27412
27413
27414
27415
27416
27417
27418
27419
27420
27421
27422
27423
27424
27425
27426
27427
27428
27429
27430
27431
27432
27433
27434
27435
27436
27437
27438
27439
27440
27441
27442
27443
27444
27445
27446
27447
27448
27449
27450
27451
27452
27453
27454
27455
27456
27457
27458
27459
27460
27461
27462
27463
27464
27465
27466
27467
27468
27469
27470
27471
27472
27473
27474
27475
27476
27477
27478
27479
27480
27481
27482
27483
27484
27485
27486
27487
27488
27489
27490
27491
27492
27493
27494
27495
27496
27497
27498
27499
27500
27501
27502
27503
27504
27505
27506
27507
27508
27509
27510
27511
27512
27513
27514
27515
27516
27517
27518
27519
27520
27521
27522
27523
27524
27525
27526
27527
27528
27529
27530
27531
27532
27533
27534
27535
27536
27537
27538
27539
27540
27541
27542
27543
27544
27545
27546
27547
27548
27549
27550
27551
27552
27553
27554
27555
27556
27557
27558
27559
27560
27561
27562
27563
27564
27565
27566
27567
27568
27569
27570
27571
27572
27573
27574
27575
27576
27577
27578
27579
27580
27581
27582
27583
27584
27585
27586
27587
27588
27589
27590
27591
27592
27593
27594
27595
27596
27597
27598
27599
27600
27601
27602
27603
27604
27605
27606
27607
27608
27609
27610
27611
27612
27613
27614
27615
27616
27617
27618
27619
27620
27621
27622
27623
27624
27625
27626
27627
27628
27629
27630
27631
27632
27633
27634
27635
27636
27637
27638
27639
27640
27641
27642
27643
27644
27645
27646
27647
27648
27649
27650
27651
27652
27653
27654
27655
27656
27657
27658
27659
27660
27661
27662
27663
27664
27665
27666
27667
27668
27669
27670
27671
27672
27673
27674
27675
27676
27677
27678
27679
27680
27681
27682
27683
27684
27685
27686
27687
27688
27689
27690
27691
27692
27693
27694
27695
27696
27697
27698
27699
27700
27701
27702
27703
27704
27705
27706
27707
27708
27709
27710
27711
27712
27713
27714
27715
27716
27717
27718
27719
27720
27721
27722
27723
27724
27725
27726
27727
27728
27729
27730
27731
27732
27733
27734
27735
27736
27737
27738
27739
27740
27741
27742
27743
27744
27745
27746
27747
27748
27749
27750
27751
27752
27753
27754
27755
27756
27757
27758
27759
27760
27761
27762
27763
27764
27765
27766
27767
27768
27769
27770
27771
27772
27773
27774
27775
27776
27777
27778
27779
27780
27781
27782
27783
27784
27785
27786
27787
27788
27789
27790
27791
27792
27793
27794
27795
27796
27797
27798
27799
27800
27801
27802
27803
27804
27805
27806
27807
27808
27809
27810
27811
27812
27813
27814
27815
27816
27817
27818
27819
27820
27821
27822
27823
27824
27825
27826
27827
27828
27829
27830
27831
27832
27833
27834
27835
27836
27837
27838
27839
27840
27841
27842
27843
27844
27845
27846
27847
27848
27849
27850
27851
27852
27853
27854
27855
27856
27857
27858
27859
27860
27861
27862
27863
27864
27865
27866
27867
27868
27869
27870
27871
27872
27873
27874
27875
27876
27877
27878
27879
27880
27881
27882
27883
27884
27885
27886
27887
27888
27889
27890
27891
27892
27893
27894
27895
27896
27897
27898
27899
27900
27901
27902
27903
27904
27905
27906
27907
27908
27909
27910
27911
27912
27913
27914
27915
27916
27917
27918
27919
27920
27921
27922
27923
27924
27925
27926
27927
27928
27929
27930
27931
27932
27933
27934
27935
27936
27937
27938
27939
27940
27941
27942
27943
27944
27945
27946
27947
27948
27949
27950
27951
27952
27953
27954
27955
27956
27957
27958
27959
27960
27961
27962
27963
27964
27965
27966
27967
27968
27969
27970
27971
27972
27973
27974
27975
27976
27977
27978
27979
27980
27981
27982
27983
27984
27985
27986
27987
27988
27989
27990
27991
27992
27993
27994
27995
27996
27997
27998
27999
28000
28001
28002
28003
28004
28005
28006
28007
28008
28009
28010
28011
28012
28013
28014
28015
28016
28017
28018
28019
28020
28021
28022
28023
28024
28025
28026
28027
28028
28029
28030
28031
28032
28033
28034
28035
28036
28037
28038
28039
28040
28041
28042
28043
28044
28045
28046
28047
28048
28049
28050
28051
28052
28053
28054
28055
28056
28057
28058
28059
28060
28061
28062
28063
28064
28065
28066
28067
28068
28069
28070
28071
28072
28073
28074
28075
28076
28077
28078
28079
28080
28081
28082
28083
28084
28085
28086
28087
28088
28089
28090
28091
28092
28093
28094
28095
28096
28097
28098
28099
28100
28101
28102
28103
28104
28105
28106
28107
28108
28109
28110
28111
28112
28113
28114
28115
28116
28117
28118
28119
28120
28121
28122
28123
28124
28125
28126
28127
28128
28129
28130
28131
28132
28133
28134
28135
28136
28137
28138
28139
28140
28141
28142
28143
28144
28145
28146
28147
28148
28149
28150
28151
28152
28153
28154
28155
28156
28157
28158
28159
28160
28161
28162
28163
28164
28165
28166
28167
28168
28169
28170
28171
28172
28173
28174
28175
28176
28177
28178
28179
28180
28181
28182
28183
28184
28185
28186
28187
28188
28189
28190
28191
28192
28193
28194
28195
28196
28197
28198
28199
28200
28201
28202
28203
28204
28205
28206
28207
28208
28209
28210
28211
28212
28213
28214
28215
28216
28217
28218
28219
28220
28221
28222
28223
28224
28225
28226
28227
28228
28229
28230
28231
28232
28233
28234
28235
28236
28237
28238
28239
28240
28241
28242
28243
28244
28245
28246
28247
28248
28249
28250
28251
28252
28253
28254
28255
28256
28257
28258
28259
28260
28261
28262
28263
28264
28265
28266
28267
28268
28269
28270
28271
28272
28273
28274
28275
28276
28277
28278
28279
28280
28281
28282
28283
28284
28285
28286
28287
28288
28289
28290
28291
28292
28293
28294
28295
28296
28297
28298
28299
28300
28301
28302
28303
28304
28305
28306
28307
28308
28309
28310
28311
28312
28313
28314
28315
28316
28317
28318
28319
28320
28321
28322
28323
28324
28325
28326
28327
28328
28329
28330
28331
28332
28333
28334
28335
28336
28337
28338
28339
28340
28341
28342
28343
28344
28345
28346
28347
28348
28349
28350
28351
28352
28353
28354
28355
28356
28357
28358
28359
28360
28361
28362
28363
28364
28365
28366
28367
28368
28369
28370
28371
28372
28373
28374
28375
28376
28377
28378
28379
28380
28381
28382
28383
28384
28385
28386
28387
28388
28389
28390
28391
28392
28393
28394
28395
28396
28397
28398
28399
28400
28401
28402
28403
28404
28405
28406
28407
28408
28409
28410
28411
28412
28413
28414
28415
28416
28417
28418
28419
28420
28421
28422
28423
28424
28425
28426
28427
28428
28429
28430
28431
28432
28433
28434
28435
28436
28437
28438
28439
28440
28441
28442
28443
28444
28445
28446
28447
28448
28449
28450
28451
28452
28453
28454
28455
28456
28457
28458
28459
28460
28461
28462
28463
28464
28465
28466
28467
28468
28469
28470
28471
28472
28473
28474
28475
28476
28477
28478
28479
28480
28481
28482
28483
28484
28485
28486
28487
28488
28489
28490
28491
28492
28493
28494
28495
28496
28497
28498
28499
28500
28501
28502
28503
28504
28505
28506
28507
28508
28509
28510
28511
28512
28513
28514
28515
28516
28517
28518
28519
28520
28521
28522
28523
28524
28525
28526
28527
28528
28529
28530
28531
28532
28533
28534
28535
28536
28537
28538
28539
28540
28541
28542
28543
28544
28545
28546
28547
28548
28549
28550
28551
28552
28553
28554
28555
28556
28557
28558
28559
28560
28561
28562
28563
28564
28565
28566
28567
28568
28569
28570
28571
28572
28573
28574
28575
28576
28577
28578
28579
28580
28581
28582
28583
28584
28585
28586
28587
28588
28589
28590
28591
28592
28593
28594
28595
28596
28597
28598
28599
28600
28601
28602
28603
28604
28605
28606
28607
28608
28609
28610
28611
28612
28613
28614
28615
28616
28617
28618
28619
28620
28621
28622
28623
28624
28625
28626
28627
28628
28629
28630
28631
28632
28633
28634
28635
28636
28637
28638
28639
28640
28641
28642
28643
28644
28645
28646
28647
28648
28649
28650
28651
28652
28653
28654
28655
28656
28657
28658
28659
28660
28661
28662
28663
28664
28665
28666
28667
28668
28669
28670
28671
28672
28673
28674
28675
28676
28677
28678
28679
28680
28681
28682
28683
28684
28685
28686
28687
28688
28689
28690
28691
28692
28693
28694
28695
28696
28697
28698
28699
28700
28701
28702
28703
28704
28705
28706
28707
28708
28709
28710
28711
28712
28713
28714
28715
28716
28717
28718
28719
28720
28721
28722
28723
28724
28725
28726
28727
28728
28729
28730
28731
28732
28733
28734
28735
28736
28737
28738
28739
28740
28741
28742
28743
28744
28745
28746
28747
28748
28749
28750
28751
28752
28753
28754
28755
28756
28757
28758
28759
28760
28761
28762
28763
28764
28765
28766
28767
28768
28769
28770
28771
28772
28773
28774
28775
28776
28777
28778
28779
28780
28781
28782
28783
28784
28785
28786
28787
28788
28789
28790
28791
28792
28793
28794
28795
28796
28797
28798
28799
28800
28801
28802
28803
28804
28805
28806
28807
28808
28809
28810
28811
28812
28813
28814
28815
28816
28817
28818
28819
28820
28821
28822
28823
28824
28825
28826
28827
28828
28829
28830
28831
28832
28833
28834
28835
28836
28837
28838
28839
28840
28841
28842
28843
28844
28845
28846
28847
28848
28849
28850
28851
28852
28853
28854
28855
28856
28857
28858
28859
28860
28861
28862
28863
28864
28865
28866
28867
28868
28869
28870
28871
28872
28873
28874
28875
28876
28877
28878
28879
28880
28881
28882
28883
28884
28885
28886
28887
28888
28889
28890
28891
28892
28893
28894
28895
28896
28897
28898
28899
28900
28901
28902
28903
28904
28905
28906
28907
28908
28909
28910
28911
28912
28913
28914
28915
28916
28917
28918
28919
28920
28921
28922
28923
28924
28925
28926
28927
28928
28929
28930
28931
28932
28933
28934
28935
28936
28937
28938
28939
28940
28941
28942
28943
28944
28945
28946
28947
28948
28949
28950
28951
28952
28953
28954
28955
28956
28957
28958
28959
28960
28961
28962
28963
28964
28965
28966
28967
28968
28969
28970
28971
28972
28973
28974
28975
28976
28977
28978
28979
28980
28981
28982
28983
28984
28985
28986
28987
28988
28989
28990
28991
28992
28993
28994
28995
28996
28997
28998
28999
29000
29001
29002
29003
29004
29005
29006
29007
29008
29009
29010
29011
29012
29013
29014
29015
29016
29017
29018
29019
29020
29021
29022
29023
29024
29025
29026
29027
29028
29029
29030
29031
29032
29033
29034
29035
29036
29037
29038
29039
29040
29041
29042
29043
29044
29045
29046
29047
29048
29049
29050
29051
29052
29053
29054
29055
29056
29057
29058
29059
29060
29061
29062
29063
29064
29065
29066
29067
29068
29069
29070
29071
29072
29073
29074
29075
29076
29077
29078
29079
29080
29081
29082
29083
29084
29085
29086
29087
29088
29089
29090
29091
29092
29093
29094
29095
29096
29097
29098
29099
29100
29101
29102
29103
29104
29105
29106
29107
29108
29109
29110
29111
29112
29113
29114
29115
29116
29117
29118
29119
29120
29121
29122
29123
29124
29125
29126
29127
29128
29129
29130
29131
29132
29133
29134
29135
29136
29137
29138
29139
29140
29141
29142
29143
29144
29145
29146
29147
29148
29149
29150
29151
29152
29153
29154
29155
29156
29157
29158
29159
29160
29161
29162
29163
29164
29165
29166
29167
29168
29169
29170
29171
29172
29173
29174
29175
29176
29177
29178
29179
29180
29181
29182
29183
29184
29185
29186
29187
29188
29189
29190
29191
29192
29193
29194
29195
29196
29197
29198
29199
29200
29201
29202
29203
29204
29205
29206
29207
29208
29209
29210
29211
29212
29213
29214
29215
29216
29217
29218
29219
29220
29221
29222
29223
29224
29225
29226
29227
29228
29229
29230
29231
29232
29233
29234
29235
29236
29237
29238
29239
29240
29241
29242
29243
29244
29245
29246
29247
29248
29249
29250
29251
29252
29253
29254
29255
29256
29257
29258
29259
29260
29261
29262
29263
29264
29265
29266
29267
29268
29269
29270
29271
29272
29273
29274
29275
29276
29277
29278
29279
29280
29281
29282
29283
29284
29285
29286
29287
29288
29289
29290
29291
29292
29293
29294
29295
29296
29297
29298
29299
29300
29301
29302
29303
29304
29305
29306
29307
29308
29309
29310
29311
29312
29313
29314
29315
29316
29317
29318
29319
29320
29321
29322
29323
29324
29325
29326
29327
29328
29329
29330
29331
29332
29333
29334
29335
29336
29337
29338
29339
29340
29341
29342
29343
29344
29345
29346
29347
29348
29349
29350
29351
29352
29353
29354
29355
29356
29357
29358
29359
29360
29361
29362
29363
29364
29365
29366
29367
29368
29369
29370
29371
29372
29373
29374
29375
29376
29377
29378
29379
29380
29381
29382
29383
29384
29385
29386
29387
29388
29389
29390
29391
29392
29393
29394
29395
29396
29397
29398
29399
29400
29401
29402
29403
29404
29405
29406
29407
29408
29409
29410
29411
29412
29413
29414
29415
29416
29417
29418
29419
29420
29421
29422
29423
29424
29425
29426
29427
29428
29429
29430
29431
29432
29433
29434
29435
29436
29437
29438
29439
29440
29441
29442
29443
29444
29445
29446
29447
29448
29449
29450
29451
29452
29453
29454
29455
29456
29457
29458
29459
29460
29461
29462
29463
29464
29465
29466
29467
29468
29469
29470
29471
29472
29473
29474
29475
29476
29477
29478
29479
29480
29481
29482
29483
29484
29485
29486
29487
29488
29489
29490
29491
29492
29493
29494
29495
29496
29497
29498
29499
29500
29501
29502
29503
29504
29505
29506
29507
29508
29509
29510
29511
29512
29513
29514
29515
29516
29517
29518
29519
29520
29521
29522
29523
29524
29525
29526
29527
29528
29529
29530
29531
29532
29533
29534
29535
29536
29537
29538
29539
29540
29541
29542
29543
29544
29545
29546
29547
29548
29549
29550
29551
29552
29553
29554
29555
29556
29557
29558
29559
29560
29561
29562
29563
29564
29565
29566
29567
29568
29569
29570
29571
29572
29573
29574
29575
29576
29577
29578
29579
29580
29581
29582
29583
29584
29585
29586
29587
29588
29589
29590
29591
29592
29593
29594
29595
29596
29597
29598
29599
29600
29601
29602
29603
29604
29605
29606
29607
29608
29609
29610
29611
29612
29613
29614
29615
29616
29617
29618
29619
29620
29621
29622
29623
29624
29625
29626
29627
29628
29629
29630
29631
29632
29633
29634
29635
29636
29637
29638
29639
29640
29641
29642
29643
29644
29645
29646
29647
29648
29649
29650
29651
29652
29653
29654
29655
29656
29657
29658
29659
29660
29661
29662
29663
29664
29665
29666
29667
29668
29669
29670
29671
29672
29673
29674
29675
29676
29677
29678
29679
29680
29681
29682
29683
29684
29685
29686
29687
29688
29689
29690
29691
29692
29693
29694
29695
29696
29697
29698
29699
29700
29701
29702
29703
29704
29705
29706
29707
29708
29709
29710
29711
29712
29713
29714
29715
29716
29717
29718
29719
29720
29721
29722
29723
29724
29725
29726
29727
29728
29729
29730
29731
29732
29733
29734
29735
29736
29737
29738
29739
29740
29741
29742
29743
29744
29745
29746
29747
29748
29749
29750
29751
29752
29753
29754
29755
29756
29757
29758
29759
29760
29761
29762
29763
29764
29765
29766
29767
29768
29769
29770
29771
29772
29773
29774
29775
29776
29777
29778
29779
29780
29781
29782
29783
29784
29785
29786
29787
29788
29789
29790
29791
29792
29793
29794
29795
29796
29797
29798
29799
29800
29801
29802
29803
29804
29805
29806
29807
29808
29809
29810
29811
29812
29813
29814
29815
29816
29817
29818
29819
29820
29821
29822
29823
29824
29825
29826
29827
29828
29829
29830
29831
29832
29833
29834
29835
29836
29837
29838
29839
29840
29841
29842
29843
29844
29845
29846
29847
29848
29849
29850
29851
29852
29853
29854
29855
29856
29857
29858
29859
29860
29861
29862
29863
29864
29865
29866
29867
29868
29869
29870
29871
29872
29873
29874
29875
29876
29877
29878
29879
29880
29881
29882
29883
29884
29885
29886
29887
29888
29889
29890
29891
29892
29893
29894
29895
29896
29897
29898
29899
29900
29901
29902
29903
29904
29905
29906
29907
29908
29909
29910
29911
29912
29913
29914
29915
29916
29917
29918
29919
29920
29921
29922
29923
29924
29925
29926
29927
29928
29929
29930
29931
29932
29933
29934
29935
29936
29937
29938
29939
29940
29941
29942
29943
29944
29945
29946
29947
29948
29949
29950
29951
29952
29953
29954
29955
29956
29957
29958
29959
29960
29961
29962
29963
29964
29965
29966
29967
29968
29969
29970
29971
29972
29973
29974
29975
29976
29977
29978
29979
29980
29981
29982
29983
29984
29985
29986
29987
29988
29989
29990
29991
29992
29993
29994
29995
29996
29997
29998
29999
30000
30001
30002
30003
30004
30005
30006
30007
30008
30009
30010
30011
30012
30013
30014
30015
30016
30017
30018
30019
30020
30021
30022
30023
30024
30025
30026
30027
30028
30029
30030
30031
30032
30033
30034
30035
30036
30037
30038
30039
30040
30041
30042
30043
30044
30045
30046
30047
30048
30049
30050
30051
30052
30053
30054
30055
30056
30057
30058
30059
30060
30061
30062
30063
30064
30065
30066
30067
30068
30069
30070
30071
30072
30073
30074
30075
30076
30077
30078
30079
30080
30081
30082
30083
30084
30085
30086
30087
30088
30089
30090
30091
30092
30093
30094
30095
30096
30097
30098
30099
30100
30101
30102
30103
30104
30105
30106
30107
30108
30109
30110
30111
30112
30113
30114
30115
30116
30117
30118
30119
30120
30121
30122
30123
30124
30125
30126
30127
30128
30129
30130
30131
30132
30133
30134
30135
30136
30137
30138
30139
30140
30141
30142
30143
30144
30145
30146
30147
30148
30149
30150
30151
30152
30153
30154
30155
30156
30157
30158
30159
30160
30161
30162
30163
30164
30165
30166
30167
30168
30169
30170
30171
30172
30173
30174
30175
30176
30177
30178
30179
30180
30181
30182
30183
30184
30185
30186
30187
30188
30189
30190
30191
30192
30193
30194
30195
30196
30197
30198
30199
30200
30201
30202
30203
30204
30205
30206
30207
30208
30209
30210
30211
30212
30213
30214
30215
30216
30217
30218
30219
30220
30221
30222
30223
30224
30225
30226
30227
30228
30229
30230
30231
30232
30233
30234
30235
30236
30237
30238
30239
30240
30241
30242
30243
30244
30245
30246
30247
30248
30249
30250
30251
30252
30253
30254
30255
30256
30257
30258
30259
30260
30261
30262
30263
30264
30265
30266
30267
30268
30269
30270
30271
30272
30273
30274
30275
30276
30277
30278
30279
30280
30281
30282
30283
30284
30285
30286
30287
30288
30289
30290
30291
30292
30293
30294
30295
30296
30297
30298
30299
30300
30301
30302
30303
30304
30305
30306
30307
30308
30309
30310
30311
30312
30313
30314
30315
30316
30317
30318
30319
30320
30321
30322
30323
30324
30325
30326
30327
30328
30329
30330
30331
30332
30333
30334
30335
30336
30337
30338
30339
30340
30341
30342
30343
30344
30345
30346
30347
30348
30349
30350
30351
30352
30353
30354
30355
30356
30357
30358
30359
30360
30361
30362
30363
30364
30365
30366
30367
30368
30369
30370
30371
30372
30373
30374
30375
30376
30377
30378
30379
30380
30381
30382
30383
30384
30385
30386
30387
30388
30389
30390
30391
30392
30393
30394
30395
30396
30397
30398
30399
30400
30401
30402
30403
30404
30405
30406
30407
30408
30409
30410
30411
30412
30413
30414
30415
30416
30417
30418
30419
30420
30421
30422
30423
30424
30425
30426
30427
30428
30429
30430
30431
30432
30433
30434
30435
30436
30437
30438
30439
30440
30441
30442
30443
30444
30445
30446
30447
30448
30449
30450
30451
30452
30453
30454
30455
30456
30457
30458
30459
30460
30461
30462
30463
30464
30465
30466
30467
30468
30469
30470
30471
30472
30473
30474
30475
30476
30477
30478
30479
30480
30481
30482
30483
30484
30485
30486
30487
30488
30489
30490
30491
30492
30493
30494
30495
30496
30497
30498
30499
30500
30501
30502
30503
30504
30505
30506
30507
30508
30509
30510
30511
30512
30513
30514
30515
30516
30517
30518
30519
30520
30521
30522
30523
30524
30525
30526
30527
30528
30529
30530
30531
30532
30533
30534
30535
30536
30537
30538
30539
30540
30541
30542
30543
30544
30545
30546
30547
30548
30549
30550
30551
30552
30553
30554
30555
30556
30557
30558
30559
30560
30561
30562
30563
30564
30565
30566
30567
30568
30569
30570
30571
30572
30573
30574
30575
30576
30577
30578
30579
30580
30581
30582
30583
30584
30585
30586
30587
30588
30589
30590
30591
30592
30593
30594
30595
30596
30597
30598
30599
30600
30601
30602
30603
30604
30605
30606
30607
30608
30609
30610
30611
30612
30613
30614
30615
30616
30617
30618
30619
30620
30621
30622
30623
30624
30625
30626
30627
30628
30629
30630
30631
30632
30633
30634
30635
30636
30637
30638
30639
30640
30641
30642
30643
30644
30645
30646
30647
30648
30649
30650
30651
30652
30653
30654
30655
30656
30657
30658
30659
30660
30661
30662
30663
30664
30665
30666
30667
30668
30669
30670
30671
30672
30673
30674
30675
30676
30677
30678
30679
30680
30681
30682
30683
30684
30685
30686
30687
30688
30689
30690
30691
30692
30693
30694
30695
30696
30697
30698
30699
30700
30701
30702
30703
30704
30705
30706
30707
30708
30709
30710
30711
30712
30713
30714
30715
30716
30717
30718
30719
30720
30721
30722
30723
30724
30725
30726
30727
30728
30729
30730
30731
30732
30733
30734
30735
30736
30737
30738
30739
30740
30741
30742
30743
30744
30745
30746
30747
30748
30749
30750
30751
30752
30753
30754
30755
30756
30757
30758
30759
30760
30761
30762
30763
30764
30765
30766
30767
30768
30769
30770
30771
30772
30773
30774
30775
30776
30777
30778
30779
30780
30781
30782
30783
30784
30785
30786
30787
30788
30789
30790
30791
30792
30793
30794
30795
30796
30797
30798
30799
30800
30801
30802
30803
30804
30805
30806
30807
30808
30809
30810
30811
30812
30813
30814
30815
30816
30817
30818
30819
30820
30821
30822
30823
30824
30825
30826
30827
30828
30829
30830
30831
30832
30833
30834
30835
30836
30837
30838
30839
30840
30841
30842
30843
30844
30845
30846
30847
30848
30849
30850
30851
30852
30853
30854
30855
30856
30857
30858
30859
30860
30861
30862
30863
30864
30865
30866
30867
30868
30869
30870
30871
30872
30873
30874
30875
30876
30877
30878
30879
30880
30881
30882
30883
30884
30885
30886
30887
30888
30889
30890
30891
30892
30893
30894
30895
30896
30897
30898
30899
30900
30901
30902
30903
30904
30905
30906
30907
30908
30909
30910
30911
30912
30913
30914
30915
30916
30917
30918
30919
30920
30921
30922
30923
30924
30925
30926
30927
30928
30929
30930
30931
30932
30933
30934
30935
30936
30937
30938
30939
30940
30941
30942
30943
30944
30945
30946
30947
30948
30949
30950
30951
30952
30953
30954
30955
30956
30957
30958
30959
30960
30961
30962
30963
30964
30965
30966
30967
30968
30969
30970
30971
30972
30973
30974
30975
30976
30977
30978
30979
30980
30981
30982
30983
30984
30985
30986
30987
30988
30989
30990
30991
30992
30993
30994
30995
30996
30997
30998
30999
31000
31001
31002
31003
31004
31005
31006
31007
31008
31009
31010
31011
31012
31013
31014
31015
31016
31017
31018
31019
31020
31021
31022
31023
31024
31025
31026
31027
31028
31029
31030
31031
31032
31033
31034
31035
31036
31037
31038
31039
31040
31041
31042
31043
31044
31045
31046
31047
31048
31049
31050
31051
31052
31053
31054
31055
31056
31057
31058
31059
31060
31061
31062
31063
31064
31065
31066
31067
31068
31069
31070
31071
31072
31073
31074
31075
31076
31077
31078
31079
31080
31081
31082
31083
31084
31085
31086
31087
31088
31089
31090
31091
31092
31093
31094
31095
31096
31097
31098
31099
31100
31101
31102
31103
31104
31105
31106
31107
31108
31109
31110
31111
31112
31113
31114
31115
31116
31117
31118
31119
31120
31121
31122
31123
31124
31125
31126
31127
31128
31129
31130
31131
31132
31133
31134
31135
31136
31137
31138
31139
31140
31141
31142
31143
31144
31145
31146
31147
31148
31149
31150
31151
31152
31153
31154
31155
31156
31157
31158
31159
31160
31161
31162
31163
31164
31165
31166
31167
31168
31169
31170
31171
31172
31173
31174
31175
31176
31177
31178
31179
31180
31181
31182
31183
31184
31185
31186
31187
31188
31189
31190
31191
31192
31193
31194
31195
31196
31197
31198
31199
31200
31201
31202
31203
31204
31205
31206
31207
31208
31209
31210
31211
31212
31213
31214
31215
31216
31217
31218
31219
31220
31221
31222
31223
31224
31225
31226
31227
31228
31229
31230
31231
31232
31233
31234
31235
31236
31237
31238
31239
31240
31241
31242
31243
31244
31245
31246
31247
31248
31249
31250
31251
31252
31253
31254
31255
31256
31257
31258
31259
31260
31261
31262
31263
31264
31265
31266
31267
31268
31269
31270
31271
31272
31273
31274
31275
31276
31277
31278
31279
31280
31281
31282
31283
31284
31285
31286
31287
31288
31289
31290
31291
31292
31293
31294
31295
31296
31297
31298
31299
31300
31301
31302
31303
31304
31305
31306
31307
31308
31309
31310
31311
31312
31313
31314
31315
31316
31317
31318
31319
31320
31321
31322
31323
31324
31325
31326
31327
31328
31329
31330
31331
31332
31333
31334
31335
31336
31337
31338
31339
31340
31341
31342
31343
31344
31345
31346
31347
31348
31349
31350
31351
31352
31353
31354
31355
31356
31357
31358
31359
31360
31361
31362
31363
31364
31365
31366
31367
31368
31369
31370
31371
31372
31373
31374
31375
31376
31377
31378
31379
31380
31381
31382
31383
31384
31385
31386
31387
31388
31389
31390
31391
31392
31393
31394
31395
31396
31397
31398
31399
31400
31401
31402
31403
31404
31405
31406
31407
31408
31409
31410
31411
31412
31413
31414
31415
31416
31417
31418
31419
31420
31421
31422
31423
31424
31425
31426
31427
31428
31429
31430
31431
31432
31433
31434
31435
31436
31437
31438
31439
31440
31441
31442
31443
31444
31445
31446
31447
31448
31449
31450
31451
31452
31453
31454
31455
31456
31457
31458
31459
31460
31461
31462
31463
31464
31465
31466
31467
31468
31469
31470
31471
31472
31473
31474
31475
31476
31477
31478
31479
31480
31481
31482
31483
31484
31485
31486
31487
31488
31489
31490
31491
31492
31493
31494
31495
31496
31497
31498
31499
31500
31501
31502
31503
31504
31505
31506
31507
31508
31509
31510
31511
31512
31513
31514
31515
31516
31517
31518
31519
31520
31521
31522
31523
31524
31525
31526
31527
31528
31529
31530
31531
31532
31533
31534
31535
31536
31537
31538
31539
31540
31541
31542
31543
31544
31545
31546
31547
31548
31549
31550
31551
31552
31553
31554
31555
31556
31557
31558
31559
31560
31561
31562
31563
31564
31565
31566
31567
31568
31569
31570
31571
31572
31573
31574
31575
31576
31577
31578
31579
31580
31581
31582
31583
31584
31585
31586
31587
31588
31589
31590
31591
31592
31593
31594
31595
31596
31597
31598
31599
31600
31601
31602
31603
31604
31605
31606
31607
31608
31609
31610
31611
31612
31613
31614
31615
31616
31617
31618
31619
31620
31621
31622
31623
31624
31625
31626
31627
31628
31629
31630
31631
31632
31633
31634
31635
31636
31637
31638
31639
31640
31641
31642
31643
31644
31645
31646
31647
31648
31649
31650
31651
31652
31653
31654
31655
31656
31657
31658
31659
31660
31661
31662
31663
31664
31665
31666
31667
31668
31669
31670
31671
31672
31673
31674
31675
31676
31677
31678
31679
31680
31681
31682
31683
31684
31685
31686
31687
31688
31689
31690
31691
31692
31693
31694
31695
31696
31697
31698
31699
31700
31701
31702
31703
31704
31705
31706
31707
31708
31709
31710
31711
31712
31713
31714
31715
31716
31717
31718
31719
31720
31721
31722
31723
31724
31725
31726
31727
31728
31729
31730
31731
31732
31733
31734
31735
31736
31737
31738
31739
31740
31741
31742
31743
31744
31745
31746
31747
31748
31749
31750
31751
31752
31753
31754
31755
31756
31757
31758
31759
31760
31761
31762
31763
31764
31765
31766
31767
31768
31769
31770
31771
31772
31773
31774
31775
31776
31777
31778
31779
31780
31781
31782
31783
31784
31785
31786
31787
31788
31789
31790
31791
31792
31793
31794
31795
31796
31797
31798
31799
31800
31801
31802
31803
31804
31805
31806
31807
31808
31809
31810
31811
31812
31813
31814
31815
31816
31817
31818
31819
31820
31821
31822
31823
31824
31825
31826
31827
31828
31829
31830
31831
31832
31833
31834
31835
31836
31837
31838
31839
31840
31841
31842
31843
31844
31845
31846
31847
31848
31849
31850
31851
31852
31853
31854
31855
31856
31857
31858
31859
31860
31861
31862
31863
31864
31865
31866
31867
31868
31869
31870
31871
31872
31873
31874
31875
31876
31877
31878
31879
31880
31881
31882
31883
31884
31885
31886
31887
31888
31889
31890
31891
31892
31893
31894
31895
31896
31897
31898
31899
31900
31901
31902
31903
31904
31905
31906
31907
31908
31909
31910
31911
31912
31913
31914
31915
31916
31917
31918
31919
31920
31921
31922
31923
31924
31925
31926
31927
31928
31929
31930
31931
31932
31933
31934
31935
31936
31937
31938
31939
31940
31941
31942
31943
31944
31945
31946
31947
31948
%  luatex.web
%
%  Copyright 2006-2009 Taco Hoekwater <taco@@luatex.org>
%  Copyright 2006-2009 Hartmut Henkel <hartmut@@luatex.org>
%
%  This file is part of LuaTeX.
%
%  LuaTeX is free software; you can redistribute it and/or modify it under
%  the terms of the GNU General Public License as published by the Free
%  Software Foundation; either version 2 of the License, or (at your
%  option) any later version.
%
%  LuaTeX is distributed in the hope that it will be useful, but WITHOUT
%  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
%  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
%  License for more details.
%
%  You should have received a copy of the GNU General Public License along
%  with LuaTeX; if not, see <http://www.gnu.org/licenses/>.
%
% $Id$

% pdfTeX is copyright (C) 1996-2006 Han The Thanh, <thanh@@pdftex.org>.
% e-TeX is copyright (C) 1994,98 by Peter Breitenlohner.

% This program is directly derived from Donald E. Knuth's TeX;
% the change history which follows and the reward offered for finders of
% bugs refer specifically to TeX; they should not be taken as referring
% to e-TeX, although the change history is relevant in that it
% demonstrates the evolutionary path followed.  This program is not TeX;
% that name is reserved strictly for the program which is the creation
% and sole responsibility of Professor Knuth.

% Version 0 was released in September 1982 after it passed a variety of tests.
% Version 1 was released in November 1983 after thorough testing.
% Version 1.1 fixed ``disappearing font identifiers'' et alia (July 1984).
% Version 1.2 allowed `0' in response to an error, et alia (October 1984).
% Version 1.3 made memory allocation more flexible and local (November 1984).
% Version 1.4 fixed accents right after line breaks, et alia (April 1985).
% Version 1.5 fixed \the\toks after other expansion in \edefs (August 1985).
% Version 2.0 (almost identical to 1.5) corresponds to "Volume B" (April 1986).
% Version 2.1 corrected anomalies in discretionary breaks (January 1987).
% Version 2.2 corrected "(Please type...)" with null \endlinechar (April 1987).
% Version 2.3 avoided incomplete page in premature termination (August 1987).
% Version 2.4 fixed \noaligned rules in indented displays (August 1987).
% Version 2.5 saved cur_order when expanding tokens (September 1987).
% Version 2.6 added 10sp slop when shipping leaders (November 1987).
% Version 2.7 improved rounding of negative-width characters (November 1987).
% Version 2.8 fixed weird bug if no \patterns are used (December 1987).
% Version 2.9 made \csname\endcsname's "relax" local (December 1987).
% Version 2.91 fixed \outer\def\a0{}\a\a bug (April 1988).
% Version 2.92 fixed \patterns, also file names with complex macros (May 1988).
% Version 2.93 fixed negative halving in allocator when mem_min<0 (June 1988).
% Version 2.94 kept open_log_file from calling fatal_error (November 1988).
% Version 2.95 solved that problem a better way (December 1988).
% Version 2.96 corrected bug in "Infinite shrinkage" recovery (January 1989).
% Version 2.97 corrected blunder in creating 2.95 (February 1989).
% Version 2.98 omitted save_for_after at outer level (March 1989).
% Version 2.99 caught $$\begingroup\halign..$$ (June 1989).
% Version 2.991 caught .5\ifdim.6... (June 1989).
% Version 2.992 introduced major changes for 8-bit extensions (September 1989).
% Version 2.993 fixed a save_stack synchronization bug et alia (December 1989).
% Version 3.0 fixed unusual displays; was more \output robust (March 1990).
% Version 3.1 fixed nullfont, disabled \write{\the\prevgraf} (September 1990).
% Version 3.14 fixed unprintable font names and corrected typos (March 1991).
% Version 3.141 more of same; reconstituted ligatures better (March 1992).
% Version 3.1415 preserved nonexplicit kerns, tidied up (February 1993).
% Version 3.14159 allowed fontmemsize to change; bulletproofing (March 1995).
% Version 3.141592 fixed \xleaders, glueset, weird alignments (December 2002).
% Version 3.1415926 was a general cleanup with minor fixes (February 2008).


% Although considerable effort has been expended to make the LuaTeX program
% correct and reliable, no warranty is implied; the authors disclaim any
% obligation or liability for damages, including but not limited to
% special, indirect, or consequential damages arising out of or in
% connection with the use or performance of this software. This work has
% been a ``labor of love'' and the authors hope that users enjoy it.

% Here is TeX material that gets inserted after \input webmac
\def\hang{\hangindent 3em\noindent\ignorespaces}
\def\hangg#1 {\hang\hbox{#1 }}
\def\textindent#1{\hangindent2.5em\noindent\hbox to2.5em{\hss#1 }\ignorespaces}
\font\ninerm=cmr9
\let\mc=\ninerm % medium caps for names like SAIL
\def\PASCAL{Pascal}
\def\pdfTeX{pdf\TeX}
\def\pdfeTeX{pdf\eTeX}
\def\PDF{PDF}
\def\Aleph{Aleph}
\def\eTeX{e\TeX}
\def\LuaTeX{Lua\TeX}
\def\THANH{H\`an Th\^e\llap{\raise 0.5ex\hbox{\'{}}} Th\`anh}
\def\ph{\hbox{Pascal-H}}
\def\pct!{{\char`\%}} % percent sign in ordinary text
\def\grp{\.{\char'173...\char'175}}
\font\logo=logo10 % font used for the METAFONT logo
\def\MF{{\logo META}\-{\logo FONT}}
\def\<#1>{$\langle#1\rangle$}
\def\section{\mathhexbox278}

\def\(#1){} % this is used to make section names sort themselves better
\def\9#1{} % this is used for sort keys in the index via @@:sort key}{entry@@>

\outer\def\N#1. \[#2]#3.{\MN#1.\vfil\eject % begin starred section
  \def\rhead{PART #2:\uppercase{#3}} % define running headline
  \message{*\modno} % progress report
  \edef\next{\write\cont{\Z{\?#2]#3}{\modno}{\the\pageno}}}\next
  \ifon\startsection{\bf\ignorespaces#3.\quad}\ignorespaces}
\let\?=\relax % we want to be able to \write a \?

\def\title{LuaTeX}
\let\maybe=\iffalse % print only changed modules
\def\topofcontents{\hsize 5.5in
  \vglue 0pt plus 1fil minus 1.5in
  \def\?##1]{\hbox to 1in{\hfil##1.\ }}
  }
\def\botofcontents{\vskip 0pt plus 1fil minus 1.5in}
\pageno=3
\def\glob{13} % this should be the section number of "<Global...>"
\def\gglob{20, 26} % this should be the next two sections of "<Global...>"

@* \[1] Introduction.

This is LuaTeX, a continuation of $\pdfTeX$ and $\Aleph$.  LuaTeX is a
document compiler intended to simplify high-quality typesetting for
many of the world's languages.  It is an extension of D. E. Knuth's
\TeX, which was designed essentially for the typesetting of languages
using the Latin alphabet.

The $\Aleph$ subsystem loosens many of the restrictions imposed by~\TeX:
register numbers are no longer limited to 8~bits;  fonts may have more
than 256~characters;  more than 256~fonts may be used;  etc.

The \PASCAL\ program that follows is the definition of \TeX82, a standard
@:PASCAL}{\PASCAL@>
@!@:TeX82}{\TeX82@>
version of \TeX\ that is designed to be highly portable so that
identical output will be obtainable on a great variety of computers.

The main purpose of the following program is to explain the algorithms of \TeX\
as clearly as possible. As a result, the program will not necessarily be very
efficient when a particular \PASCAL\ compiler has translated it into a
particular machine language. However, the program has been written so that it
can be tuned to run efficiently in a wide variety of operating environments
by making comparatively few changes. Such flexibility is possible because
the documentation that follows is written in the \.{WEB} language, which is
at a higher level than \PASCAL; the preprocessing step that converts \.{WEB}
to \PASCAL\ is able to introduce most of the necessary refinements.
Semi-automatic translation to other languages is also feasible, because the
program below does not make extensive use of features that are peculiar to
\PASCAL.

A large piece of software like \TeX\ has inherent complexity that cannot
be reduced below a certain level of difficulty, although each individual
part is fairly simple by itself. The \.{WEB} language is intended to make
the algorithms as readable as possible, by reflecting the way the
individual program pieces fit together and by providing the
cross-references that connect different parts. Detailed comments about
what is going on, and about why things were done in certain ways, have
been liberally sprinkled throughout the program.  These comments explain
features of the implementation, but they rarely attempt to explain the
\TeX\ language itself, since the reader is supposed to be familiar with
{\sl The \TeX book}.
@.WEB@>
@:TeXbook}{\sl The \TeX book@>

@ The present implementation has a long ancestry, beginning in the summer
of~1977, when Michael~F. Plass and Frank~M. Liang designed and coded
a prototype
@^Plass, Michael Frederick@>
@^Liang, Franklin Mark@>
@^Knuth, Donald Ervin@>
based on some specifications that the author had made in May of that year.
This original proto\TeX\ included macro definitions and elementary
manipulations on boxes and glue, but it did not have line-breaking,
page-breaking, mathematical formulas, alignment routines, error recovery,
or the present semantic nest; furthermore,
it used character lists instead of token lists, so that a control sequence
like \.{\\halign} was represented by a list of seven characters. A
complete version of \TeX\ was designed and coded by the author in late
1977 and early 1978; that program, like its prototype, was written in the
{\mc SAIL} language, for which an excellent debugging system was
available. Preliminary plans to convert the {\mc SAIL} code into a form
somewhat like the present ``web'' were developed by Luis Trabb~Pardo and
@^Trabb Pardo, Luis Isidoro@>
the author at the beginning of 1979, and a complete implementation was
created by Ignacio~A. Zabala in 1979 and 1980. The \TeX82 program, which
@^Zabala Salelles, Ignacio Andr\'es@>
was written by the author during the latter part of 1981 and the early
part of 1982, also incorporates ideas from the 1979 implementation of
@^Guibas, Leonidas Ioannis@>
@^Sedgewick, Robert@>
@^Wyatt, Douglas Kirk@>
\TeX\ in {\mc MESA} that was written by Leonidas Guibas, Robert Sedgewick,
and Douglas Wyatt at the Xerox Palo Alto Research Center.  Several hundred
refinements were introduced into \TeX82 based on the experiences gained with
the original implementations, so that essentially every part of the system
has been substantially improved. After the appearance of ``Version 0'' in
September 1982, this program benefited greatly from the comments of
many other people, notably David~R. Fuchs and Howard~W. Trickey.
A final revision in September 1989 extended the input character set to
eight-bit codes and introduced the ability to hyphenate words from
different languages, based on some ideas of Michael~J. Ferguson.
@^Fuchs, David Raymond@>
@^Trickey, Howard Wellington@>
@^Ferguson, Michael John@>

No doubt there still is plenty of room for improvement, but the author
is firmly committed to keeping \TeX82 ``frozen'' from now on; stability
and reliability are to be its main virtues.

On the other hand, the \.{WEB} description can be extended without changing
the core of \TeX82 itself, and the program has been designed so that such
extensions are not extremely difficult to make.
The |banner| string defined here should be changed whenever \TeX\
undergoes any modifications, so that it will be clear which version of
\TeX\ might be the guilty party when a problem arises.
@^extensions to \TeX@>
@^system dependencies@>

This program contains code for various features extending \TeX,
therefore this program is called `\eTeX' and not
`\TeX'; the official name `\TeX' by itself is reserved
for software systems that are fully compatible with each other.
A special test suite called the ``\.{TRIP} test'' is available for
helping to determine whether a particular implementation deserves to be
known as `\TeX' [cf.~Stanford Computer Science report CS1027,
November 1984].

A similar test suite called the ``\.{e-TRIP} test'' is available for
helping to determine whether a particular implementation deserves to be
known as `\eTeX'.

@d eTeX_version_string=="2.2" {current \eTeX\ version}
@d Omega_version_string=="1.15" { \.{\\OmegaVersion} }
@d Aleph_version_string=="0.0" { \.{\\AlephVersion} }
@d eTeX_version=2 { \.{\\eTeXversion} }
@d Omega_version=1 { \.{\\Omegaversion} }
@d Aleph_version=0 { \.{\\Alephversion} }
@d eTeX_minor_version=1 { \.{\\eTeXminorversion} }
@d Omega_minor_version=15 { \.{\\Omegaminorversion} }
@d Aleph_minor_version=0 { \.{\\Alephminorversion} }
@d eTeX_revision==".2" { \.{\\eTeXrevision} }
@d Omega_revision==".15" { \.{\\Omegarevision} }
@d Aleph_revision==".0" { \.{\\Alephrevision} }
@#
@d pdftex_version==200 { \.{\\pdftexversion} }
@d pdftex_revision=="0" { \.{\\pdftexrevision} }
@d pdftex_version_string=='-2.00.0' {current \pdfTeX\ version}
@#
@d luatex_version==40 { \.{\\luatexversion} }
@d luatex_revision=="2" { \.{\\luatexrevision} }
@d luatex_version_string=='beta-0.40.2' {current \LuaTeX\ version}
@d luatex_date_info==-extra_version_info { the compile date is negated }
@d luatex_svnversion=='$Id$'
   {for long --version information, as proposed by Peter M\"unster}
@#
@d LuaTeX_banner=='This is LuaTeX, Version ',luatex_version_string,extra_version_info
   {printed when \LuaTeX\ starts}
@#
@d banner==LuaTeX_banner
@#
@d TEX==ETEX {change program name into |ETEX|}

@ Different \PASCAL s have slightly different conventions, and the present
@!@:PASCAL H}{\ph@>
program expresses \TeX\ in terms of the \PASCAL\ that was
available to the author in 1982. Constructions that apply to
this particular compiler, which we shall call \ph, should help the
reader see how to make an appropriate interface for other systems
if necessary. (\ph\ is Charles Hedrick's modification of a compiler
@^Hedrick, Charles Locke@>
for the DECsystem-10 that was originally developed at the University of
Hamburg; cf.\ {\sl SOFTWARE---Practice \AM\ Experience \bf6} (1976),
29--42. The \TeX\ program below is intended to be adaptable, without
extensive changes, to most other versions of \PASCAL, so it does not fully
use the admirable features of \ph. Indeed, a conscious effort has been
made here to avoid using several idiosyncratic features of standard
\PASCAL\ itself, so that most of the code can be translated mechanically
into other high-level languages. For example, the `\&{with}' and `\\{new}'
features are not used, nor are pointer types, set types, or enumerated
scalar types; there are no `\&{var}' parameters, except in the case of files
--- \eTeX, however, does use `\&{var}' parameters for the |reverse| function;
there are no tag fields on variant records; there are no assignments
|real:=integer|; no procedures are declared local to other procedures.)

The portions of this program that involve system-dependent code, where
changes might be necessary because of differences between \PASCAL\ compilers
and/or differences between
operating systems, can be identified by looking at the sections whose
numbers are listed under `system dependencies' in the index. Furthermore,
the index entries for `dirty \PASCAL' list all places where the restrictions
of \PASCAL\ have not been followed perfectly, for one reason or another.
@!@^system dependencies@>
@!@^dirty \PASCAL@>

Incidentally, \PASCAL's standard |round| function can be problematical,
because it disagrees with the IEEE floating-point standard.
Many implementors have
therefore chosen to substitute their own home-grown rounding procedure.

@ The program begins with a normal \PASCAL\ program heading, whose
components will be filled in later, using the conventions of \.{WEB}.
@.WEB@>
For example, the portion of the program called `\X\glob:Global
variables\X' below will be replaced by a sequence of variable declarations
that starts in $\section\glob$ of this documentation. In this way, we are able
to define each individual global variable when we are prepared to
understand what it means; we do not have to define all of the globals at
once.  Cross references in $\section\glob$, where it says ``See also
sections \gglob, \dots,'' also make it possible to look at the set of
all global variables, if desired.  Similar remarks apply to the other
portions of the program heading.

Actually the heading shown here is not quite normal: The |program| line
does not mention any |output| file, because \ph\ would ask the \TeX\ user
to specify a file name if |output| were specified here.
@:PASCAL H}{\ph@>
@^system dependencies@>

@d mtype==t@&y@&p@&e {this is a \.{WEB} coding trick:}
@f mtype==type {`\&{mtype}' will be equivalent to `\&{type}'}
@f type==true {but `|type|' will not be treated as a reserved word}

@p @t\4@>@<Compiler directives@>@/
program TEX; {all file names are defined dynamically}
label @<Labels in the outer block@>@/
const @<Constants in the outer block@>@/
mtype @<Types in the outer block@>@/
var @<Global variables@>@/
@#
procedure initialize; {this procedure gets things started properly}
  var @<Local variables for initialization@>@/
  begin @<Initialize whatever \TeX\ might access@>@;
  end;@#
@t\4@>@<Basic printing procedures@>@/
@t\4@>@<Error handling procedures@>@/

@ Here is a workaround for the unfortunate limitation of WEB2C that
doesn't know how to deal with symbolic case labels.

@d hlist_node_case==0
@d vlist_node_case==1
@d rule_node_case==2
@d ins_node_case==3
@d mark_node_case==4
@d adjust_node_case==5
@d disc_node_case==7
@d whatsit_node_case==8
@d math_node_case==9
@d glue_node_case==10
@d kern_node_case==11
@d penalty_node_case==12
@d unset_node_case==13
@d margin_kern_node_case==36

@<Initialize whatever \TeX\ might access@>=
pdfassert(hlist_node_case=hlist_node);
pdfassert(vlist_node_case=vlist_node);
pdfassert(rule_node_case=rule_node);
pdfassert(ins_node_case=ins_node);
pdfassert(mark_node_case=mark_node);
pdfassert(adjust_node_case=adjust_node);
pdfassert(disc_node_case=disc_node);
pdfassert(whatsit_node_case=whatsit_node);
pdfassert(math_node_case=math_node);
pdfassert(glue_node_case=glue_node);
pdfassert(kern_node_case=kern_node);
pdfassert(penalty_node_case=penalty_node);
pdfassert(unset_node_case=unset_node);
pdfassert(margin_kern_node_case=margin_kern_node);





@ The overall \TeX\ program begins with the heading just shown, after which
comes a bunch of procedure declarations and function declarations.
Finally we will get to the main program, which begins with the
comment `|start_here|'. If you want to skip down to the
main program now, you can look up `|start_here|' in the index.
But the author suggests that the best way to understand this program
is to follow pretty much the order of \TeX's components as they appear in the
\.{WEB} description you are now reading, since the present ordering is
intended to combine the advantages of the ``bottom up'' and ``top down''
approaches to the problem of understanding a somewhat complicated system.

@ Three labels must be declared in the main program, so we give them
symbolic names.

@d start_of_TEX=1 {go here when \TeX's variables are initialized}
@d end_of_TEX=9998 {go here to close files and terminate gracefully}
@d final_end=9999 {this label marks the ending of the program}

@<Labels in the out...@>=
start_of_TEX@t\hskip-2pt@>, end_of_TEX@t\hskip-2pt@>,@,final_end;
  {key control points}

@ Some of the code below is intended to be used only when diagnosing the
strange behavior that sometimes occurs when \TeX\ is being installed or
when system wizards are fooling around with \TeX\ without quite knowing
what they are doing. Such code will not normally be compiled; it is
delimited by the codewords `$|debug|\ldots|gubed|$', with apologies
to people who wish to preserve the purity of English.

Similarly, there is some conditional code delimited by
`$|stat|\ldots|tats|$' that is intended for use when statistics are to be
kept about \TeX's memory usage.  The |stat| $\ldots$ |tats| code also
implements diagnostic information for \.{\\tracingparagraphs} and
\.{\\tracingpages}.
@^debugging@>

@d debug==@{ {change this to `$\\{debug}\equiv\null$' when debugging}
@d gubed==@t@>@} {change this to `$\\{gubed}\equiv\null$' when debugging}
@f debug==begin
@f gubed==end
@#
@d stat==@{ {change this to `$\\{stat}\equiv\null$' when gathering
  usage statistics}
@d tats==@t@>@} {change this to `$\\{tats}\equiv\null$' when gathering
  usage statistics}
@f stat==begin
@f tats==end

@ This program has two important variations: (1) There is a long and slow
version called \.{INITEX}, which does the extra calculations needed to
@.INITEX@>
initialize \TeX's internal tables; and (2)~there is a shorter and faster
production version, which cuts the initialization to a bare minimum.
Parts of the program that are needed in (1) but not in (2) are delimited by
the codewords `$|init|\ldots|tini|$'.

@d init== {change this to `$\\{init}\equiv\.{@@\{}$' in the production version}
@d tini== {change this to `$\\{tini}\equiv\.{@@\}}$' in the production version}
@f init==begin
@f tini==end

@<Initialize whatever...@>=
@<Set initial values of key variables@>@/
@!init @<Initialize table entries (done by \.{INITEX} only)@>@;@+tini

@ If the first character of a \PASCAL\ comment is a dollar sign,
\ph\ treats the comment as a list of ``compiler directives'' that will
affect the translation of this program into machine language.  The
directives shown below specify full checking and inclusion of the \PASCAL\
debugger when \TeX\ is being debugged, but they cause range checking and other
redundant code to be eliminated when the production system is being generated.
Arithmetic overflow will be detected in all cases.
@:PASCAL H}{\ph@>
@^system dependencies@>
@^overflow in arithmetic@>

@<Compiler directives@>=
@{@&$C-,A+,D-@} {no range check, catch arithmetic overflow, no debug overhead}
@!debug @{@&$C+,D+@}@+ gubed {but turn everything on when debugging}

@ This \TeX\ implementation conforms to the rules of the {\sl Pascal User
@:PASCAL}{\PASCAL@>
@^system dependencies@>
Manual} published by Jensen and Wirth in 1975, except where system-dependent
@^Wirth, Niklaus@>
@^Jensen, Kathleen@>
code is necessary to make a useful system program, and except in another
respect where such conformity would unnecessarily obscure the meaning
and clutter up the code: We assume that |case| statements may include a
default case that applies if no matching label is found. Thus, we shall use
constructions like
$$\vbox{\halign{\ignorespaces#\hfil\cr
|case x of|\cr
1: $\langle\,$code for $x=1\,\rangle$;\cr
3: $\langle\,$code for $x=3\,\rangle$;\cr
|othercases| $\langle\,$code for |x<>1| and |x<>3|$\,\rangle$\cr
|endcases|\cr}}$$
since most \PASCAL\ compilers have plugged this hole in the language by
incorporating some sort of default mechanism. For example, the \ph\
compiler allows `|others|:' as a default label, and other \PASCAL s allow
syntaxes like `\&{else}' or `\&{otherwise}' or `\\{otherwise}:', etc. The
definitions of |othercases| and |endcases| should be changed to agree with
local conventions.  Note that no semicolon appears before |endcases| in
this program, so the definition of |endcases| should include a semicolon
if the compiler wants one. (Of course, if no default mechanism is
available, the |case| statements of \TeX\ will have to be laboriously
extended by listing all remaining cases. People who are stuck with such
\PASCAL s have, in fact, done this, successfully but not happily!)
@:PASCAL H}{\ph@>

@d othercases == others: {default for cases not listed explicitly}
@d endcases == @+end {follows the default case in an extended |case| statement}
@f othercases == else
@f endcases == end

@ The following parameters can be changed at compile time to extend or
reduce \TeX's capacity. They may have different values in \.{INITEX} and
in production versions of \TeX.
@.INITEX@>
@^system dependencies@>

@<Constants...@>=
@!buf_size=500; {maximum number of characters simultaneously present in
  current lines of open files and in control sequences between
  \.{\\csname} and \.{\\endcsname}; must not exceed |max_halfword|}
@!error_line=72; {width of context lines on terminal error messages}
@!half_error_line=42; {width of first lines of contexts in terminal
  error messages; should be between 30 and |error_line-15|}
@!max_print_line=79; {width of longest text lines output; should be at least 60}
@!stack_size=200; {maximum number of simultaneous input sources}
@!max_in_open=6; {maximum number of input files and error insertions that
  can be going on simultaneously}
@!param_size=60; {maximum number of simultaneous macro parameters}
@!nest_size=40; {maximum number of semantic levels simultaneously active}
@!max_strings=3000; {maximum number of strings; must not exceed |max_halfword|}
@!string_vacancies=8000; {the minimum number of characters that should be
  available for the user's control sequences and font names,
  after \TeX's own error messages are stored}
@!pool_size=32000; {maximum number of characters in strings, including all
  error messages and help texts, and the names of all fonts and
  control sequences; must exceed |string_vacancies| by the total
  length of \TeX's own strings, which is currently about 23000}
@!save_size=600; {space for saving values outside of current group; must be
  at most |max_halfword|}
@!dvi_buf_size=800; {size of the output buffer; must be a multiple of 8}
@!expand_depth=10000; {limits recursive calls of the |expand| procedure}
@!file_name_size=40; {file names shouldn't be longer than this}
@!pool_name='TeXformats:TEX.POOL                     ';
  {string of length |file_name_size|; tells where the string pool appears}
@.TeXformats@>
@!active_mem_size=50000; {number of words of |active_info| for active ocps}
@!ocp_maxint=@"10000000;


@ Like the preceding parameters, the following quantities can be changed
at compile time to extend or reduce \TeX's capacity. But if they are changed,
it is necessary to rerun the initialization program \.{INITEX}
@.INITEX@>
to generate new tables for the production \TeX\ program.
One can't simply make helter-skelter changes to the following constants,
since certain rather complex initialization
numbers are computed from them. They are defined here using
\.{WEB} macros, instead of being put into \PASCAL's |const| list, in order to
emphasize this distinction.

@d font_base=0 {smallest internal font number; must not be less
  than |min_quarterword|}
@d hash_size=65536 {maximum number of control sequences; it should be at most
  about |(fix_mem_max-fix_mem_min)/10|}
@d ocp_base=0 {smallest internal ocp number; must not be less
  than |min_quarterword|}
@d ocp_biggest=32767 {the real biggest ocp}
@d number_ocps=ocp_biggest-ocp_base+1
@d ocp_list_base=0 {smallest internal ocp list number; must not be less
  than |min_quarterword|}
@d ocp_list_biggest=32727 {the real biggest ocp list}
@d number_ocp_lists=ocp_list_biggest-ocp_list_base+1
@d max_active_ocp_lists=32768
@d biggest_reg=65535 {the largest allowed register number; must be |<=max_quarterword|}
@d number_regs=65536 {|biggest_reg+1|}
@d number_attrs=65536 {total numbeer of attributes}
@d biggest_mark=65535 {the largest allowed marks class; must be |<=max_quarterword|}
@d number_marks=65536 {|biggest_mark+1|}
{using |2^20+2^16| characters instead of |2^21| saves 286MB on the virtual memory size
 of the running executable}
@d biggest_char=1114111 {2097151} {the largest allowed character number; must be |<=max_halfword|}
@d too_big_char=1114112 {2097152} {|biggest_char+1|}
@d special_char=1114113 {2097153} {|biggest_char+2|}
@d number_chars=1114112 {2097152} {|biggest_char+1|}
@d string_offset=2097152
@d font_biggest=5535 {the real biggest font}
@d number_fonts=font_biggest-font_base+1
@d biggest_lang=32767
@d too_big_lang=32768
@d text_size=0 {size code for the largest size in a family}
@d script_size=1 {size code for the medium size in a family}
@d script_script_size=2 {size code for the smallest size in a family}


@ In case somebody has inadvertently made bad settings of the ``constants,''
\TeX\ checks them using a global variable called |bad|.

This is the first of many sections of \TeX\ where global variables are
defined.

@<Glob...@>=
@!bad:integer; {is some ``constant'' wrong?}
@!luainit:boolean; {are we using lua for initializations }
@!tracefilenames:boolean; { print file open-close  info? }

@ Later on we will say `\ignorespaces|if X>=max_halfword then bad:=14|',
or something similar. (We can't do that until |max_halfword| has been defined.)

@<Check the ``constant'' values for consistency@>=
bad:=0;
if not luainit then  tracefilenames:=true;
if (half_error_line<30)or(half_error_line>error_line-15) then bad:=1;
if max_print_line<60 then bad:=2;
if dvi_buf_size mod 8<>0 then bad:=3;
if hash_prime>hash_size then bad:=5;
if max_in_open>=128 then bad:=6;
{ |if null_list<256 then bad:=7;| } {we will want |null_list>255|}

@ Labels are given symbolic names by the following definitions, so that
occasional |goto| statements will be meaningful. We insert the label
`|exit|' just before the `\ignorespaces|end|\unskip' of a procedure in
which we have used the `|return|' statement defined below; the label
`|restart|' is occasionally used at the very beginning of a procedure; and
the label `|reswitch|' is occasionally used just prior to a |case|
statement in which some cases change the conditions and we wish to branch
to the newly applicable case.  Loops that are set up with the |loop|
construction defined below are commonly exited by going to `|done|' or to
`|found|' or to `|not_found|', and they are sometimes repeated by going to
`|continue|'.  If two or more parts of a subroutine start differently but
end up the same, the shared code may be gathered together at
`|common_ending|'.

Incidentally, this program never declares a label that isn't actually used,
because some fussy \PASCAL\ compilers will complain about redundant labels.

@d exit=10 {go here to leave a procedure}
@d restart=20 {go here to start a procedure again}
@d reswitch=21 {go here to start a case statement again}
@d continue=22 {go here to resume a loop}
@d done=30 {go here to exit a loop}
@d done1=31 {like |done|, when there is more than one loop}
@d done2=32 {for exiting the second loop in a long block}
@d done3=33 {for exiting the third loop in a very long block}
@d done4=34 {for exiting the fourth loop in an extremely long block}
@d done5=35 {for exiting the fifth loop in an immense block}
@d done6=36 {for exiting the sixth loop in a block}
@d found=40 {go here when you've found it}
@d found1=41 {like |found|, when there's more than one per routine}
@d found2=42 {like |found|, when there's more than two per routine}
@d not_found=45 {go here when you've found nothing}
@d not_found1=46 {like |not_found|, when there's more than one}
@d not_found2=47 {like |not_found|, when there's more than two}
@d not_found3=48 {like |not_found|, when there's more than three}
@d not_found4=49 {like |not_found|, when there's more than four}
@d common_ending=50 {go here when you want to merge with another branch}

@ Here are some macros for common programming idioms.

@d incr(#) == #:=#+1 {increase a variable by unity}
@d decr(#) == #:=#-1 {decrease a variable by unity}
@d negate(#) == #:=-# {change the sign of a variable}
@d loop == @+ while true do@+ {repeat over and over until a |goto| happens}
@f loop == xclause
  {\.{WEB}'s |xclause| acts like `\ignorespaces|while true do|\unskip'}
@d do_nothing == pdfassert(1) {empty statement}
@d return == goto exit {terminate a procedure call}
@f return == nil
@d empty=0 {symbolic name for a null constant}

@* \[2] The character set.
In order to make \TeX\ readily portable to a wide variety of
computers, all of its input text is converted to an internal
twenty-one-bit code that covers all of unicode, including ASCII, the
``American Standard Code for Information Interchange.''  This
conversion is done immediately when each character is read
in. Conversely, characters are converted from ASCII to the user's
external representation just before they are output to a text file.

Such an internal code is relevant to users of \TeX\ primarily because it
governs the positions of characters in the fonts. For example, the
character `\.A' has ASCII code $65=@'101$, and when \TeX\ typesets
this letter it specifies character number 65 in the current font.
If that font actually has `\.A' in a different position, \TeX\ doesn't
know what the real position is; the program that does the actual printing from
\TeX's device-independent files is responsible for converting from ASCII to
a particular font encoding.
@^ASCII code@>

\TeX's internal code also defines the value of constants
that begin with a reverse apostrophe; and it provides an index to the
\.{\\catcode}, \.{\\mathcode}, \.{\\uccode}, \.{\\lccode}, and \.{\\delcode}
tables.

@ Characters of text that have been converted to \TeX's internal form
are said to be of type |ASCII_code|, which is a subrange of the integers.

@<Types...@>=
@!ASCII_code=0..biggest_char; {eight-bit numbers}
@!BMP_code=0..65535; {sixteen-bit numbers}

@ The original \PASCAL\ compiler was designed in the late 60s, when six-bit
character sets were common, so it did not make provision for lowercase
letters. Nowadays, of course, we need to deal with both capital and small
letters in a convenient way, especially in a program for typesetting;
so the present specification of \TeX\ has been written under the assumption
that the \PASCAL\ compiler and run-time system permit the use of text files
with more than 64 distinguishable characters. More precisely, we assume that
the character set contains at least the letters and symbols associated
with ASCII codes @'40 through @'176; all of these characters are now
available on most computer terminals.

Since we are dealing with more characters than were present in the first
\PASCAL\ compilers, we have to decide what to call the associated data
type. Some \PASCAL s use the original name |char| for the
characters in text files, even though there now are more than 64 such
characters, while other \PASCAL s consider |char| to be a 64-element
subrange of a larger data type that has some other name.

In order to accommodate this difference, we shall use the name |text_char|
to stand for the data type of the characters that are converted to and
from |ASCII_code| when they are input and output. We shall also assume
that |text_char| consists of the elements |chr(first_text_char)| through
|chr(last_text_char)|, inclusive. The following definitions should be
adjusted if necessary.
@^system dependencies@>

@d text_char == char {the data type of characters in text files}
@d first_text_char=0 {ordinal number of the smallest element of |text_char|}
@d last_text_char=255 {ordinal number of the largest element of |text_char|}

@<Local variables for init...@>=
@!i:integer;

@ The \TeX\ processor converts between ASCII code and
the user's external character set by means of arrays |xord| and |xchr|
that are analogous to \PASCAL's |ord| and |chr| functions.

@<Glob...@>=
@!xchr: array [ASCII_code] of text_char;
  {specifies conversion of output characters}

@ Since we are assuming that our \PASCAL\ system is able to read and
write the visible characters of standard ASCII (although not
necessarily using the ASCII codes to represent them), the following
assignment statements initialize the standard part of the |xchr| array
properly, without needing any system-dependent changes. On the other
hand, it is possible to implement \TeX\ with less complete character
sets, and in such cases it will be necessary to change something here.
@^system dependencies@>

@<Set init...@>=
xchr[@'40]:=' ';
xchr[@'41]:='!';
xchr[@'42]:='"';
xchr[@'43]:='#';
xchr[@'44]:='$';
xchr[@'45]:='%';
xchr[@'46]:='&';
xchr[@'47]:='''';@/
xchr[@'50]:='(';
xchr[@'51]:=')';
xchr[@'52]:='*';
xchr[@'53]:='+';
xchr[@'54]:=',';
xchr[@'55]:='-';
xchr[@'56]:='.';
xchr[@'57]:='/';@/
xchr[@'60]:='0';
xchr[@'61]:='1';
xchr[@'62]:='2';
xchr[@'63]:='3';
xchr[@'64]:='4';
xchr[@'65]:='5';
xchr[@'66]:='6';
xchr[@'67]:='7';@/
xchr[@'70]:='8';
xchr[@'71]:='9';
xchr[@'72]:=':';
xchr[@'73]:=';';
xchr[@'74]:='<';
xchr[@'75]:='=';
xchr[@'76]:='>';
xchr[@'77]:='?';@/
xchr[@'100]:='@@';
xchr[@'101]:='A';
xchr[@'102]:='B';
xchr[@'103]:='C';
xchr[@'104]:='D';
xchr[@'105]:='E';
xchr[@'106]:='F';
xchr[@'107]:='G';@/
xchr[@'110]:='H';
xchr[@'111]:='I';
xchr[@'112]:='J';
xchr[@'113]:='K';
xchr[@'114]:='L';
xchr[@'115]:='M';
xchr[@'116]:='N';
xchr[@'117]:='O';@/
xchr[@'120]:='P';
xchr[@'121]:='Q';
xchr[@'122]:='R';
xchr[@'123]:='S';
xchr[@'124]:='T';
xchr[@'125]:='U';
xchr[@'126]:='V';
xchr[@'127]:='W';@/
xchr[@'130]:='X';
xchr[@'131]:='Y';
xchr[@'132]:='Z';
xchr[@'133]:='[';
xchr[@'134]:='\';
xchr[@'135]:=']';
xchr[@'136]:='^';
xchr[@'137]:='_';@/
xchr[@'140]:='`';
xchr[@'141]:='a';
xchr[@'142]:='b';
xchr[@'143]:='c';
xchr[@'144]:='d';
xchr[@'145]:='e';
xchr[@'146]:='f';
xchr[@'147]:='g';@/
xchr[@'150]:='h';
xchr[@'151]:='i';
xchr[@'152]:='j';
xchr[@'153]:='k';
xchr[@'154]:='l';
xchr[@'155]:='m';
xchr[@'156]:='n';
xchr[@'157]:='o';@/
xchr[@'160]:='p';
xchr[@'161]:='q';
xchr[@'162]:='r';
xchr[@'163]:='s';
xchr[@'164]:='t';
xchr[@'165]:='u';
xchr[@'166]:='v';
xchr[@'167]:='w';@/
xchr[@'170]:='x';
xchr[@'171]:='y';
xchr[@'172]:='z';
xchr[@'173]:='{';
xchr[@'174]:='|';
xchr[@'175]:='}';
xchr[@'176]:='~';@/

@ Some of the ASCII codes without visible characters have been given symbolic
names in this program because they are used with a special meaning.

@d null_code=@'0 {ASCII code that might disappear}
@d carriage_return=@'15 {ASCII code used at end of line}
@d invalid_code=@'177 {ASCII code that many systems prohibit in text files}

@ The ASCII code is ``standard'' only to a certain extent, since many
computer installations have found it advantageous to have ready access
to more than 94 printing characters. Appendix~C of {\sl The \TeX book\/}
gives a complete specification of the intended correspondence between
characters and \TeX's internal representation.
@:TeXbook}{\sl The \TeX book@>

If \TeX\ is being used
on a garden-variety \PASCAL\ for which only standard ASCII
codes will appear in the input and output files, it doesn't really matter
what codes are specified in |xchr[0..@'37]|, but the safest policy is to
blank everything out by using the code shown below.

However, other settings of |xchr| will make \TeX\ more friendly on
computers that have an extended character set, so that users can type things
like `\.^^Z' instead of `\.{\\ne}'. People with extended character sets can
assign codes arbitrarily, giving an |xchr| equivalent to whatever
characters the users of \TeX\ are allowed to have in their input files.
It is best to make the codes correspond to the intended interpretations as
shown in Appendix~C whenever possible; but this is not necessary. For
example, in countries with an alphabet of more than 26 letters, it is
usually best to map the additional letters into codes less than~@'40.
To get the most ``permissive'' character set, change |' '| on the
right of these assignment statements to |chr(i)|.
@^character set dependencies@>
@^system dependencies@>

@<Set init...@>=
for i:=0 to biggest_char do xchr[i]:=i;

@ The following system-independent code makes the |xord| array contain a
suitable inverse to the information in |xchr|. Note that if |xchr[i]=xchr[j]|
where |i<j<@'177|, the value of |xord[xchr[i]]| will turn out to be
|j| or more; hence, standard ASCII code numbers will be used instead of
codes below @'40 in case there is a coincidence.

@<Set init...@>=

@* \[3] Input and output.
The bane of portability is the fact that different operating systems treat
input and output quite differently, perhaps because computer scientists
have not given sufficient attention to this problem. People have felt somehow
that input and output are not part of ``real'' programming. Well, it is true
that some kinds of programming are more fun than others. With existing
input/output conventions being so diverse and so messy, the only sources of
joy in such parts of the code are the rare occasions when one can find a
way to make the program a little less bad than it might have been. We have
two choices, either to attack I/O now and get it over with, or to postpone
I/O until near the end. Neither prospect is very attractive, so let's
get it over with.

The basic operations we need to do are (1)~inputting and outputting of
text, to or from a file or the user's terminal; (2)~inputting and
outputting of eight-bit bytes, to or from a file; (3)~instructing the
operating system to initiate (``open'') or to terminate (``close'') input or
output from a specified file; (4)~testing whether the end of an input
file has been reached.

\TeX\ needs to deal with two kinds of files.
We shall use the term |alpha_file| for a file that contains textual data,
and the term |byte_file| for a file that contains eight-bit binary information.
These two types turn out to be the same on many computers, but
sometimes there is a significant distinction, so we shall be careful to
distinguish between them. Standard protocols for transferring
such files from computer to computer, via high-speed networks, are
now becoming available to more and more communities of users.

The program actually makes use also of a third kind of file, called a
|word_file|, when dumping and reloading base information for its own
initialization.  We shall define a word file later; but it will be possible
for us to specify simple operations on word files before they are defined.

@<Types...@>=
@!eight_bits=0..65535; {unsigned one-byte quantity}
@!real_eight_bits=0..255; {unsigned one-byte quantity}
@!alpha_file=packed file of text_char; {files that contain textual data}
@!byte_file=packed file of real_eight_bits; {files that contain binary data}

@ Most of what we need to do with respect to input and output can be handled
by the I/O facilities that are standard in \PASCAL, i.e., the routines
called |get|, |put|, |eof|, and so on. But
standard \PASCAL\ does not allow file variables to be associated with file
names that are determined at run time, so it cannot be used to implement
\TeX; some sort of extension to \PASCAL's ordinary |reset| and |rewrite|
is crucial for our purposes. We shall assume that |nameoffile| is a variable
of an appropriate type such that the \PASCAL\ run-time system being used to
implement \TeX\ can open a file whose external name is specified by
|nameoffile|.
@^system dependencies@>

@<Glob...@>=
@!nameoffile:packed array[1..file_name_size] of char;@;@/
  {on some systems this may be a \&{record} variable}
@!namelength:0..file_name_size;@/{this many characters are actually
  relevant in |nameoffile| (the rest are blank)}
@!name_file_pointer:alpha_file;

@ The \ph\ compiler with which the present version of \TeX\ was prepared has
extended the rules of \PASCAL\ in a very convenient way. To open file~|f|,
we can write
$$\vbox{\halign{#\hfil\qquad&#\hfil\cr
|reset(f,@t\\{name}@>,'/O')|&for input;\cr
|rewrite(f,@t\\{name}@>,'/O')|&for output.\cr}}$$
The `\\{name}' parameter, which is of type `{\bf packed array
$[\langle\\{any}\rangle]$ of \\{char}}', stands for the name of
the external file that is being opened for input or output.
Blank spaces that might appear in \\{name} are ignored.

The `\.{/O}' parameter tells the operating system not to issue its own
error messages if something goes wrong. If a file of the specified name
cannot be found, or if such a file cannot be opened for some other reason
(e.g., someone may already be trying to write the same file), we will have
|@!erstat(f)<>0| after an unsuccessful |reset| or |rewrite|.  This allows
\TeX\ to undertake appropriate corrective action.
@:PASCAL H}{\ph@>
@^system dependencies@>

\TeX's file-opening procedures return |false| if no file identified by
|nameoffile| could be opened.

@d reset_OK(#)==erstat(#)=0
@d rewrite_OK(#)==erstat(#)=0

@p function a_open_in(var f:alpha_file):boolean;
  {open a text file for input}
begin reset(f,nameoffile,'/O'); a_open_in:=reset_OK(f);
end;
@#
function a_open_out(var f:alpha_file):boolean;
  {open a text file for output}
begin rewrite(f,nameoffile,'/O'); a_open_out:=rewrite_OK(f);
end;
@#
function b_open_in(var f:byte_file):boolean;
  {open a binary file for input}
begin reset(f,nameoffile,'/O'); b_open_in:=reset_OK(f);
end;
@#
function b_open_out(var f:byte_file):boolean;
  {open a binary file for output}
begin rewrite(f,nameoffile,'/O'); b_open_out:=rewrite_OK(f);
end;
@#
function w_open_in(var f:word_file):boolean;
  {open a word file for input}
begin reset(f,nameoffile,'/O'); w_open_in:=reset_OK(f);
end;
@#
function w_open_out(var f:word_file):boolean;
  {open a word file for output}
begin rewrite(f,nameoffile,'/O'); w_open_out:=rewrite_OK(f);
end;

@ When input files are opened via a callback, they will also be read using
callbacks. for that purpose, the |open_read_file_callback| returns an
integer to uniquely identify a callback table. This id replaces the file
point |f| in this case, because the input does not have to be a file
in the traditional sense.

Signalling this fact is achieved by having two arrays of integers.

@<Glob...@>=
@!input_file_callback_id : ^integer;
@!read_file_callback_id : array[0..16] of integer;

@
@p function lua_a_open_in(var f:alpha_file; n:quarterword):boolean;
var k:integer; { a temporary value }
  fnam:str_number; { string returned by find callback }
  callback_id:integer;
  file_ok:boolean; { the status so far }
begin
  file_ok:=true;
  if n=0 then begin
    texinputtype := 1; {Tell |open_input| we are \.{\\input}.}
    input_file_callback_id[index] := 0;
    end
  else begin
    texinputtype:=0;
    read_file_callback_id[n] := 0;
    end;
  callback_id:=callback_defined(find_read_file_callback);
  if callback_id>0 then begin
    fnam:=0;
    file_ok:=run_callback(callback_id,'dS->s',n,stringcast(nameoffile+1),addressof(fnam));
    if (file_ok)and(fnam<>0)and(length(fnam)>0) then begin
      @<Fixup |nameoffile| after callback@>;
      end
    else
      file_ok:=false; {file not found}
    end;
  if file_ok then begin
    callback_id:=callback_defined(open_read_file_callback);
    if callback_id>0 then begin
      k := run_and_save_callback(callback_id,'S->',stringcast(nameoffile+1));
      if k>0 then begin
        lua_a_open_in := true;
        if n=0 then
          input_file_callback_id[index] := k
        else
          read_file_callback_id[n] := k;
        end
      else
        file_ok:=false; {read failed}
      end
    else begin {no read callback}
      if openinnameok(stringcast(nameoffile+1)) then begin
        lua_a_open_in := a_open_in(f,kpsetexformat);
        name_file_pointer := f;
        end
      else
        file_ok:=false; {open failed}
      end;
    end;
  if not file_ok then begin
    lua_a_open_in := false;
    name_file_pointer := 0;
    end;
end;
@#
function lua_a_open_out(var f:alpha_file; n:quarterword):boolean;
var test:boolean;
  k:integer;
  fnam:str_number;
  callback_id:integer;
begin
  name_file_pointer := 0;
  callback_id:=callback_defined(find_write_file_callback);
  if callback_id>0 then begin
    fnam:=0;
    test:=run_callback(callback_id,'dS->s',n,stringcast(nameoffile+1),addressof(fnam));
    if (test)and(fnam<>0)and(length(fnam)>0) then begin
      @<Fixup |nameoffile| after callback@>;
      lua_a_open_out := do_a_open_out(f);
          name_file_pointer := f;
      end
    else
      lua_a_open_out := false;
    end
  else begin
        if openoutnameok(stringcast(nameoffile+1)) then begin
      lua_a_open_out := a_open_out(f);
      name_file_pointer := f;
      end
    else
      lua_a_open_out := false;
   end;
end;
function lua_b_open_out(var f:alpha_file):boolean;
var test:boolean;
  k:integer;
  fnam:str_number;
  callback_id:integer;
begin
  name_file_pointer := 0;
  callback_id:=callback_defined(find_output_file_callback);
  if callback_id>0 then begin
    fnam:=0;
    test:=run_callback(callback_id,'S->s',stringcast(nameoffile+1),addressof(fnam));
    if (test)and(fnam<>0)and(length(fnam)>0) then begin
      @<Fixup |nameoffile| after callback@>;
      lua_b_open_out := do_b_open_out(f);
          name_file_pointer := f;
      end
    else
      lua_b_open_out := false;
    end
  else begin
        if openoutnameok(stringcast(nameoffile+1)) then begin
      lua_b_open_out := b_open_out(f);
      name_file_pointer := f;
      end
    else
      lua_b_open_out := false;
   end;
end;

@
@<Fixup |nameoffile| after callback@>=
libcfree (nameoffile);
nameoffile := xmallocarray (packed_ASCII_code, length(fnam)+2);
for k:=str_start_macro(fnam) to str_start_macro(fnam+1)-1 do
  nameoffile[k-str_start_macro(fnam)+1] := str_pool[k];
nameoffile[length(fnam)+1]:=0;
namelength := length(fnam);
flush_string

@ Files can be closed with the \ph\ routine `|close(f)|', which
@:PASCAL H}{\ph@>
@^system dependencies@>
should be used when all input or output with respect to |f| has been completed.
This makes |f| available to be opened again, if desired; and if |f| was used for
output, the |close| operation makes the corresponding external file appear
on the user's area, ready to be read.

These procedures should not generate error messages if a file is
being closed before it has been successfully opened.

@p procedure a_close(var f:alpha_file); {close a text file}
begin close(f);
end;
@#
procedure b_close(var f:byte_file); {close a binary file}
begin close(f);
end;
@#
procedure w_close(var f:word_file); {close a word file}
begin close(f);
end;


@

@p procedure lua_a_close_in(var f:alpha_file; n:quarterword); {close a text file}
var ret:boolean;
    callback_id:integer;
begin
if n=0 then
  callback_id:=input_file_callback_id[index]
else
  callback_id:=read_file_callback_id[n];
if callback_id>0 then begin
  ret:=run_saved_callback(callback_id,'close','->');
  destroy_saved_callback(callback_id);
  if n=0 then
    input_file_callback_id[index] := 0
  else
    read_file_callback_id[n] := 0;
  end
else
  a_close(f);
end;
@#
procedure lua_a_close_out(var f:alpha_file); {close a text file}
begin
  a_close(f);
end;


@ Binary input and output are done with \PASCAL's ordinary |get| and |put|
procedures, so we don't have to make any other special arrangements for
binary~I/O. Text output is also easy to do with standard \PASCAL\ routines.
The treatment of text input is more difficult, however, because
of the necessary translation to |ASCII_code| values.
\TeX's conventions should be efficient, and they should
blend nicely with the user's operating environment.

@ Input from text files is read one line at a time, using a routine called
|lua_input_ln|. This function is defined in terms of global variables called
|buffer|, |first|, and |last| that will be described in detail later; for
now, it suffices for us to know that |buffer| is an array of |ASCII_code|
values, and that |first| and |last| are indices into this array
representing the beginning and ending of a line of text.

@<Glob...@>=
@!buffer:array[0..buf_size] of packed_ASCII_code; {lines of characters being read}
@!first:0..buf_size; {the first unused position in |buffer|}
@!last:0..buf_size; {end of the line just input to |buffer|}
@!max_buf_stack:0..buf_size; {largest index used in |buffer|}

@ The |lua_input_ln| function brings the next line of input from the specified
file into available positions of the buffer array and returns the value
|true|, unless the file has already been entirely read, in which case it
returns |false| and sets |last:=first|.  In general, the |ASCII_code|
numbers that represent the next line of the file are input into
|buffer[first]|, |buffer[first+1]|, \dots, |buffer[last-1]|; and the
global variable |last| is set equal to |first| plus the length of the
line. Trailing blanks are removed from the line; thus, either |last=first|
(in which case the line was entirely blank) or |buffer[last-1]<>" "|.

An overflow error is given, however, if the normal actions of |lua_input_ln|
would make |last>=buf_size|; this is done so that other parts of \TeX\
can safely look at the contents of |buffer[last+1]| without overstepping
the bounds of the |buffer| array. Upon entry to |lua_input_ln|, the condition
|first<buf_size| will always hold, so that there is always room for an
``empty'' line.

The variable |max_buf_stack|, which is used to keep track of how large
the |buf_size| parameter must be to accommodate the present job, is
also kept up to date by |lua_input_ln|.

If the |bypass_eoln| parameter is |true|, |lua_input_ln| will do a |get|
before looking at the first character of the line; this skips over
an |eoln| that was in |f^|. The procedure does not do a |get| when it
reaches the end of the line; therefore it can be used to acquire input
from the user's terminal as well as from ordinary text files.

Standard \PASCAL\ says that a file should have |eoln| immediately
before |eof|, but \TeX\ needs only a weaker restriction: If |eof|
occurs in the middle of a line, the system function |eoln| should return
a |true| result (even though |f^| will be undefined).

Since the inner loop of |lua_input_ln| is part of \TeX's ``inner loop''---each
character of input comes in at this place---it is wise to reduce system
overhead by making use of special routines that read in an entire array
of characters at once, if such routines are available. The following
code uses standard \PASCAL\ to illustrate what needs to be done, but
finer tuning is often possible at well-developed \PASCAL\ sites.
@^inner loop@>

@p function input_ln(var f:alpha_file;@!bypass_eoln:boolean):boolean;
  {inputs the next line or returns |false|}
var last_nonblank:0..buf_size; {|last| with trailing blanks removed}
begin if bypass_eoln then if not eof(f) then get(f);
  {input the first character of the line into |f^|}
last:=first; {cf.\ Matthew 19\thinspace:\thinspace30}
if eof(f) then input_ln:=false
else  begin last_nonblank:=first;
  while not eoln(f) do
    begin if last>=max_buf_stack then
      begin max_buf_stack:=last+1;
      if max_buf_stack=buf_size then
        @<Report overflow of the input buffer, and abort@>;
      end;
    buffer[last]:=f^; get(f); incr(last);
    if buffer[last-1]<>" " then last_nonblank:=last;
    end;
  last:=last_nonblank; input_ln:=true;
  end;
end;

function lua_input_ln(var f:alpha_file;n:quarterword;@!bypass_eoln:boolean):boolean;
var lua_result:boolean;
        last_ptr:integer;
    callback_id:integer;
        bypass_p:boolean;
begin
if n=0 then
  callback_id:=input_file_callback_id[index]
else
  callback_id:=read_file_callback_id[n];
if callback_id>0 then begin
    last:=first;
        last_ptr := first;
    lua_result := run_saved_callback(callback_id,'reader','->l', addressof(last_ptr));
        if (lua_result=true)and(last_ptr<>0) then begin
          last := last_ptr;
          if last>max_buf_stack then max_buf_stack:=last;
          lua_input_ln := true;
      @<Fix up the input buffer using callbacks@>;
      end
    else
      lua_input_ln := false;
    end
  else begin
    bypass_p := bypass_eoln; {this is for -Wextra}
    lua_result := input_ln(f,bypass_p);
        if lua_result=true then begin
      lua_input_ln := true;
      @<Fix up the input buffer using callbacks@>;
      end
    else
      lua_input_ln := false;
    end
end;

@
@<Fix up the input buffer using callbacks@>=
if last>=first then begin
  callback_id := callback_defined(process_input_buffer_callback);
  if callback_id>0 then begin
    last_ptr := first;
    lua_result := run_callback(callback_id, 'l->l', (last-first), addressof(last_ptr));
    if (lua_result=true)and(last_ptr<>0) then begin
          last := last_ptr;
          if last>max_buf_stack then max_buf_stack:=last;
      end;
    end;
  end



@ The user's terminal acts essentially like other files of text, except
that it is used both for input and for output. When the terminal is
considered an input file, the file variable is called |term_in|, and when it
is considered an output file the file variable is |term_out|.
@^system dependencies@>

@<Glob...@>=
@!term_in:alpha_file; {the terminal as an input file}
@!term_out:alpha_file; {the terminal as an output file}

@ Here is how to open the terminal files
in \ph. The `\.{/I}' switch suppresses the first |get|.
@:PASCAL H}{\ph@>
@^system dependencies@>

@d t_open_in==reset(term_in,'TTY:','/O/I') {open the terminal for text input}
@d t_open_out==rewrite(term_out,'TTY:','/O') {open the terminal for text output}

@ Sometimes it is necessary to synchronize the input/output mixture that
happens on the user's terminal, and three system-dependent
procedures are used for this
purpose. The first of these, |update_terminal|, is called when we want
to make sure that everything we have output to the terminal so far has
actually left the computer's internal buffers and been sent.
The second, |clear_terminal|, is called when we wish to cancel any
input that the user may have typed ahead (since we are about to
issue an unexpected error message). The third, |wake_up_terminal|,
is supposed to revive the terminal if the user has disabled it by
some instruction to the operating system.  The following macros show how
these operations can be specified in \ph:
@:PASCAL H}{\ph@>
@^system dependencies@>

@d update_terminal == break(term_out) {empty the terminal output buffer}
@d clear_terminal == break_in(term_in,true) {clear the terminal input buffer}
@d wake_up_terminal == do_nothing {cancel the user's cancellation of output}

@ We need a special routine to read the first line of \TeX\ input from
the user's terminal. This line is different because it is read before we
have opened the transcript file; there is sort of a ``chicken and
egg'' problem here. If the user types `\.{\\input paper}' on the first
line, or if some macro invoked by that line does such an \.{\\input},
the transcript file will be named `\.{paper.log}'; but if no \.{\\input}
commands are performed during the first line of terminal input, the transcript
file will acquire its default name `\.{texput.log}'. (The transcript file
will not contain error messages generated by the first line before the
first \.{\\input} command.)
@.texput@>

The first line is even more special if we are lucky enough to have an operating
system that treats \TeX\ differently from a run-of-the-mill \PASCAL\ object
program. It's nice to let the user start running a \TeX\ job by typing
a command line like `\.{tex paper}'; in such a case, \TeX\ will operate
as if the first line of input were `\.{paper}', i.e., the first line will
consist of the remainder of the command line, after the part that invoked
\TeX.

The first line is special also because it may be read before \TeX\ has
input a format file. In such cases, normal error messages cannot yet
be given. The following code uses concepts that will be explained later.
(If the \PASCAL\ compiler does not support non-local |@!goto|\unskip, the
@^system dependencies@>
statement `|goto final_end|' should be replaced by something that
quietly terminates the program.)

@<Report overflow of the input buffer, and abort@>=
if format_ident=0 then
  begin writeln(term_out,'Buffer size exceeded!'); goto final_end;
@.Buffer size exceeded@>
  end
else
  check_buffer_overflow(buf_size+10) { need  a little bit more}

@ Different systems have different ways to get started. But regardless of
what conventions are adopted, the routine that initializes the terminal
should satisfy the following specifications:

\yskip\textindent{1)}It should open file |term_in| for input from the
  terminal. (The file |term_out| will already be open for output to the
  terminal.)

\textindent{2)}If the user has given a command line, this line should be
  considered the first line of terminal input. Otherwise the
  user should be prompted with `\.{**}', and the first line of input
  should be whatever is typed in response.

\textindent{3)}The first line of input, which might or might not be a
  command line, should appear in locations |first| to |last-1| of the
  |buffer| array.

\textindent{4)}The global variable |loc| should be set so that the
  character to be read next by \TeX\ is in |buffer[loc]|. This
  character should not be blank, and we should have |loc<last|.

\yskip\noindent(It may be necessary to prompt the user several times
before a non-blank line comes in. The prompt is `\.{**}' instead of the
later `\.*' because the meaning is slightly different: `\.{\\input}' need
not be typed immediately after~`\.{**}'.)

@d loc==cur_input.loc_field {location of first unread character in |buffer|}

@ The following program does the required initialization
without retrieving a possible command line.
It should be clear how to modify this routine to deal with command lines,
if the system permits them.
@^system dependencies@>

@p function init_terminal:boolean; {gets the terminal input started}
label exit;
begin t_open_in;
loop@+begin wake_up_terminal; write(term_out,'**'); update_terminal;
@.**@>
  if not input_ln(term_in,true)
then {this shouldn't happen}
    begin writeln(term_out);
    write(term_out,'! End of file on the terminal... why?');
@.End of file on the terminal@>
    init_terminal:=false; return;
    end;
  loc:=first;
  while (loc<last)and(buffer[loc]=" ") do incr(loc);
  if loc<last then
    begin init_terminal:=true;
    return; {return unless the line was all blank}
    end;
  writeln(term_out,'Please type the name of your input file.');
  end;
exit:end;

@* \[4] String handling.
Control sequence names and diagnostic messages are variable-length strings
of eight-bit characters. Since \PASCAL\ does not have a well-developed string
mechanism, \TeX\ does all of its string processing by homegrown methods.

Elaborate facilities for dynamic strings are not needed, so all of the
necessary operations can be handled with a simple data structure.
The array |str_pool| contains all of the (eight-bit) ASCII codes in all
of the strings, and the array |str_start| contains indices of the starting
points of each string. Strings are referred to by integer numbers, so that
string number |s| comprises the characters |str_pool[j]| for
|str_start_macro(s)<=j<str_start_macro(s+1)|. Additional integer variables
|pool_ptr| and |str_ptr| indicate the number of entries used so far
in |str_pool| and |str_start|, respectively; locations
|str_pool[pool_ptr]| and |str_start_macro(str_ptr)| are
ready for the next string to be allocated.

String numbers 0 to |biggest_char| are reserved for strings that correspond to single
UNICODE characters. This is in accordance with the conventions of \.{WEB},
@.WEB@>
which converts single-character strings into the ASCII code number of the
single character involved, while it converts other strings into integers
and builds a string pool file. Thus, when the string constant \.{"."} appears
in the program below, \.{WEB} converts it into the integer 46, which is the
ASCII code for a period, while \.{WEB} will convert a string like \.{"hello"}
into some integer greater than~|biggest_char|.

Some \PASCAL\ compilers won't pack integers into a single byte unless the
integers lie in the range |-128..127|. To accommodate such systems
we access the string pool only via macros that can easily be redefined.
@^system dependencies@>

@d si(#) == # {convert from |ASCII_code| to |packed_ASCII_code|}
@d so(#) == # {convert from |packed_ASCII_code| to |ASCII_code|}
@d str_start_macro(#) == str_start[(#) - string_offset]

@<Types...@>=
@!pool_pointer = integer; {for variables that point into |str_pool|}
@!str_number = integer; {for variables that point into |str_start|}
@!packed_ASCII_code = 0..255; {elements of |str_pool| array}

@ @<Glob...@>=
@!str_pool:packed array[pool_pointer] of packed_ASCII_code; {the characters}
@!str_start : array[str_number] of pool_pointer; {the starting pointers}
@!pool_ptr : pool_pointer; {first unused position in |str_pool|}
@!str_ptr : str_number; {number of the current string being created}
@!init_pool_ptr : pool_pointer; {the starting value of |pool_ptr|}
@!init_str_ptr : str_number; {the starting value of |str_ptr|}

@ Several of the elementary string operations are performed using \.{WEB}
macros instead of \PASCAL\ procedures, because many of the
operations are done quite frequently and we want to avoid the
overhead of procedure calls. For example, here is
a simple macro that computes the length of a string.
@.WEB@>

@d length(#)==(str_start_macro(#+1)-str_start_macro(#)) {the number of characters
  in string number \#}

@ The length of the current string is called |cur_length|:

@d cur_length == (pool_ptr - str_start_macro(str_ptr))

@ Strings are created by appending character codes to |str_pool|.
The |append_char| macro, defined here, does not check to see if the
value of |pool_ptr| has gotten too high; this test is supposed to be
made before |append_char| is used. There is also a |flush_char|
macro, which erases the last character appended.

To test if there is room to append |l| more characters to |str_pool|,
we shall write |str_room(l)|, which aborts \TeX\ and gives an
apologetic error message if there isn't enough room.

@d append_char(#) == {put |ASCII_code| \# at the end of |str_pool|}
begin str_pool[pool_ptr]:=si(#); incr(pool_ptr);
end
@d flush_char == decr(pool_ptr) {forget the last character in the pool}
@d str_room(#) == check_pool_overflow((pool_ptr+#)) {test or grow the pool}

@p procedure string_room(t:integer);
begin
        str_room(t);
end;
@#
procedure append_pool_char(c:ASCII_code);
begin
        append_char(c);
end;


@ Once a sequence of characters has been appended to |str_pool|, it
officially becomes a string when the function |make_string| is called.
This function returns the identification number of the new string as its
value.

@p function make_string : str_number; {current string enters the pool}
begin if str_ptr=(max_strings+string_offset) then
  overflow("number of strings",max_strings-init_str_ptr);
@:TeX capacity exceeded number of strings}{\quad number of strings@>
incr(str_ptr); str_start_macro(str_ptr):=pool_ptr;
make_string:=str_ptr-1;
end;

@ To destroy the most recently made string, we say |flush_string|.

The helper routines reads one utf sequence from the pool resp. the
buffer, and returns its character value.

@d flush_string==begin decr(str_ptr); pool_ptr:=str_start_macro(str_ptr);
  end
@d test_sequence_byte(#)==if (#<@"80) or (#>=@"C0) then begin
  print_err("Text line contains an invalid utf-8 sequence");
@.Text line contains...@>
  help2("A funny symbol that I can't read has just been input.")@/
    ("Just continue, I'll change it to 0xFFFD.");@/
  deletions_allowed:=false; error; deletions_allowed:=true;
{the assigment before return is needed because web2c generates incorrect code}
  a:=@"FFFD; buffer_to_unichar:=a; return; end


@p function buffer_to_unichar(@!k:integer):integer;
label exit;
var a:@!integer; {a utf char}
b:@!integer; { a utf nibble}
begin
    b := buffer[k];
    if b<@"80 then
      a := b
    else if b>=@"F0 then begin
          a := (b-@"F0) * 64;
          b := buffer[k+1];
          test_sequence_byte(b);
          a := (a + (b-128)) * 64;
          b := buffer[k+2];
          test_sequence_byte(b);
          a := (a + (b-128)) * 64;
          b := buffer[k+3];
          test_sequence_byte(b);
          a := a + (b-128);
      end
    else if b>=@"E0 then begin
          a := (b-@"E0) * 64;
          b := buffer[k+1];
          test_sequence_byte(b);
          a := (a + (b-128)) * 64;
          b := buffer[k+2];
          test_sequence_byte(b);
          a := a + (b-128);
      end
    else if b>=@"C0 then begin
          a := (b-@"C0) * 64;
          b := buffer[k+1];
          test_sequence_byte(b);
          a := a + (b-128);
      end
    else begin { NI: this is an encoding error }
          print_err("Buffer contains an invalid utf-8 sequence");
@.Text line contains...@>
          help2("A funny symbol somehow ended up in the input buffer.")@/
           ("Just continue, I'll change it to 0xFFFD.");@/
      deletions_allowed:=false; error; deletions_allowed:=true;
      a:=@"FFFD;
      end;
exit:
  buffer_to_unichar := a;
end ;



@ The following subroutine compares string |s| with another string of the
same length that appears in |buffer| starting at position |k|;
the result is |true| if and only if the strings are equal.
Empirical tests indicate that |str_eq_buf| is used in such a way that
it tends to return |true| about 80 percent of the time.

@p function str_eq_buf(@!s:str_number;@!k:integer):boolean;
  {test equality of strings}
label not_found; {loop exit}
var j: pool_pointer; {running index}
a: ASCII_code; {a unicode character }
@!result: boolean; {result of comparison}
begin result:=false;
if s<string_offset then begin
  a := buffer_to_unichar(k);
  if a<>s then goto not_found;
  end
else begin
j:=str_start_macro(s);
while j<str_start_macro(s+1) do
  begin if so(str_pool[j])<>buffer[k] then
    begin goto not_found;
    end;
  incr(j); incr(k);
  end;
end;
result:=true;
not_found: str_eq_buf:=result;
end;

@ Here is a similar routine, but it compares two strings in the string pool,
and it does not assume that they have the same length.

@p function str_eq_str(@!s,@!t:str_number):boolean;
  {test equality of strings}
label found,not_found; {loop exit}
var j,@!k: pool_pointer; {running indices}
a: ASCII_code; {a utf char}
@!result: boolean; {result of comparison}
begin result:=false;
a:= 0;
if s<string_offset then begin
  if t>=string_offset then begin
    if s<=@"7F then
     if length(t)=1 then
       if str_pool[str_start_macro(t)]=s then
          goto found;
        a := pool_to_unichar(str_start_macro(t));
    if a<>s then goto not_found;
    end
  else
    if t<>s then goto not_found;
  end
else if t<string_offset then begin
 if t<=@"7F then
   if length(s)=1 then
     if str_pool[str_start_macro(s)]=t then
       goto found;
  a := pool_to_unichar(str_start_macro(s));
  if a<>t then goto not_found;
  end
else begin
  if length(s)<>length(t) then goto not_found;
  j:=str_start_macro(s); k:=str_start_macro(t);
  while j<str_start_macro(s+1) do
    begin if str_pool[j]<>str_pool[k] then goto not_found;
    incr(j); incr(k);
    end;
  end;
found: result:=true;
not_found: str_eq_str:=result;
end;

@ The initial values of |str_pool|, |str_start|, |pool_ptr|,
and |str_ptr| are computed by the \.{INITEX} program, based in part
on the information that \.{WEB} has output while processing \TeX.
@.INITEX@>
@^string pool@>

The first |string_offset| strings are single-characters strings matching
Unicode. There is no point in generating all of these. But |str_ptr| has
initialized properly, otherwise |print_char| cannot see the difference
between characters and strings.

@p @!init function get_strings_started:boolean; {initializes the string pool,
  but returns |false| if something goes wrong}
label done,exit;
var @!g:str_number; {garbage}
begin pool_ptr:=0; str_ptr:=string_offset; str_start[0]:=0;
@<Read the other strings from the \.{TEX.POOL} file and return |true|,
  or give an error message and return |false|@>;
exit:end;
tini

@ @d app_lc_hex(#)==l:=#;
  if l<10 then append_char(l+"0")@+else append_char(l-10+"a")

@ The first 128 strings will contain 95 standard ASCII characters, and the
other 33 characters will be printed in three-symbol form like `\.{\^\^A}'
unless a system-dependent change is made here. Installations that have
an extended character set, where for example |xchr[@'32]=@t\.{\'^^Z\'}@>|,
would like string @'32 to be the single character @'32 instead of the
three characters @'136, @'136, @'132 (\.{\^\^Z}). On the other hand,
even people with an extended character set will want to represent string
@'15 by \.{\^\^M}, since @'15 is |carriage_return|; the idea is to
produce visible strings instead of tabs or line-feeds or carriage-returns
or bell-rings or characters that are treated anomalously in text files.

Unprintable characters of codes 128--255 are, similarly, rendered
\.{\^\^80}--\.{\^\^ff}.

Unprintable characters of codes 256--|65535| are, similarly, rendered
\.{\^\^\^\^0100}--\.{\^\^\^\^ffff}.

The boolean expression defined here should be |true| unless \TeX\
internal code number~|k| corresponds to a non-troublesome visible
symbol in the local character set.  An appropriate formula for the
extended character set recommended in {\sl The \TeX book\/} would, for
example, be `|k in [0,@'10..@'12,@'14,@'15,@'33,@'177..@'377]|'.
If character |k| cannot be printed, and |k<@'200|, then character |k+@'100| or
|k-@'100| must be printable; moreover, ASCII codes |[@'41..@'46,
@'60..@'71, @'136, @'141..@'146, @'160..@'171]| must be printable.
Thus, at least 81 printable characters are needed.
@:TeXbook}{\sl The \TeX book@>
@^character set dependencies@>
@^system dependencies@>

@ @<Read the other strings...@>=
  g := loadpoolstrings((pool_size-string_vacancies));
  if g=0 then begin
     wake_up_terminal; writeln(term_out,'! You have to increase POOLSIZE.');
     get_strings_started:=false;
     return;
  end;
  get_strings_started:=true;

@* \[5] On-line and off-line printing.
Messages that are sent to a user's terminal and to the transcript-log file
are produced by several `|print|' procedures. These procedures will
direct their output to a variety of places, based on the setting of
the global variable |selector|, which has the following possible
values:

\yskip
\hang |term_and_log|, the normal setting, prints on the terminal and on the
  transcript file.

\hang |log_only|, prints only on the transcript file.

\hang |term_only|, prints only on the terminal.

\hang |no_print|, doesn't print at all. This is used only in rare cases
  before the transcript file is open.

\hang |pseudo|, puts output into a cyclic buffer that is used
  by the |show_context| routine; when we get to that routine we shall discuss
  the reasoning behind this curious mode.

\hang |new_string|, appends the output to the current string in the
  string pool.

\hang 0 to 15, prints on one of the sixteen files for \.{\\write} output.

\yskip
\noindent The symbolic names `|term_and_log|', etc., have been assigned
numeric codes that satisfy the convenient relations |no_print+1=term_only|,
|no_print+2=log_only|, |term_only+2=log_only+1=term_and_log|.

Three additional global variables, |tally| and |term_offset| and
|file_offset|, record the number of characters that have been printed
since they were most recently cleared to zero. We use |tally| to record
the length of (possibly very long) stretches of printing; |term_offset|
and |file_offset|, on the other hand, keep track of how many characters
have appeared so far on the current line that has been output to the
terminal or to the transcript file, respectively.

@d no_print=16 {|selector| setting that makes data disappear}
@d term_only=17 {printing is destined for the terminal only}
@d log_only=18 {printing is destined for the transcript file only}
@d term_and_log=19 {normal |selector| setting}
@d pseudo=20 {special |selector| setting for |show_context|}
@d new_string=21 {printing is deflected to the string pool}
@d max_selector=21 {highest selector setting}

@<Glob...@>=
@!log_file : alpha_file; {transcript of \TeX\ session}
@!term_out_mode:halfword;
@!term_out_translation:halfword;
@!selector : 0..max_selector; {where to print a message}
@!dig : array[0..22] of 0..15; {digits in a number being output}
@!tally : integer; {the number of characters recently printed}
@!term_offset : 0..max_print_line;
  {the number of characters on the current terminal line}
@!file_offset : 0..max_print_line;
  {the number of characters on the current file line}
@!trick_buf:array[0..error_line] of packed_ASCII_code; {circular buffer for
  pseudoprinting}
@!trick_count: integer; {threshold for pseudoprinting, explained later}
@!first_count: integer; {another variable for pseudoprinting}
@!inhibit_par_tokens:boolean; { for minor adjustments to |show_token_list| }

@ @<Initialize the output routines@>=
selector:=term_only; tally:=0; term_offset:=0; file_offset:=0;
inhibit_par_tokens:=false;

@ Macro abbreviations for output to the terminal and to the log file are
defined here for convenience. Some systems need special conventions
for terminal output, and it is possible to adhere to those conventions
by changing |wterm|, |wterm_ln|, and |wterm_cr| in this section.
@^system dependencies@>

@d wterm(#)==write(term_out,#)
@d wterm_ln(#)==writeln(term_out,#)
@d wterm_cr==writeln(term_out)
@d wlog(#)==write(log_file,#)
@d wlog_ln(#)==writeln(log_file,#)
@d wlog_cr==writeln(log_file)

@ To end a line of text output, we call |print_ln|.

@<Basic print...@>=
procedure print_ln; {prints an end-of-line}
begin case selector of
term_and_log: begin wterm_cr; wlog_cr;
  term_offset:=0; file_offset:=0;
  end;
log_only: begin wlog_cr; file_offset:=0;
  end;
term_only: begin wterm_cr; term_offset:=0;
  end;
no_print,pseudo,new_string: do_nothing;
othercases writeln(write_file[selector])
endcases;@/
end; {|tally| is not affected}

@ The |print_char| procedure sends one character to the desired destination,
using the |xchr| array to map it into an external character compatible with
|lua_input_ln|. All printing comes through |print_ln| or |print_char|.

@d wterm_char(#)==begin if (#>=@"20)or(#=@"0A)or(#=@"0D)or(#=@"09) then wterm(xchr[#])
                  else begin if term_offset+2>=max_print_line then begin
                     wterm_cr; term_offset:=0;
                     end;
                     incr(term_offset); wterm('^'); incr(term_offset); wterm('^');
                     wterm(xchr[#+64]);
                 end; end
@d fix_term_offset(#)==
      if ((#>=@"C0) and (#<=@"DF) and (term_offset+2>=max_print_line)) or
         ((#>=@"E0) and (#<=@"EF) and (term_offset+3>=max_print_line)) or
         ((#>=@"F0) and (term_offset+4>=max_print_line)) then begin
        wterm_cr; term_offset:=0;
       end
@d fix_log_offset(#)==
      if ((#>=@"C0) and (#<=@"DF) and (file_offset+2>=max_print_line)) or
         ((#>=@"E0) and (#<=@"EF) and (file_offset+3>=max_print_line)) or
         ((#>=@"F0) and (file_offset+4>=max_print_line)) then begin
        wlog_cr; file_offset:=0;
       end

@<Basic print...@>=
procedure print_char(@!s:ASCII_code); {prints a single character}
label exit;
begin if @<Character |s| is the current new-line character@> then
 if selector<pseudo then
  begin print_ln; return;
  end;
case selector of
term_and_log: begin
  fix_term_offset(s); fix_log_offset(s);
  wterm_char(s); wlog(xchr[s]);
  incr(term_offset); incr(file_offset);
  if term_offset=max_print_line then
    begin wterm_cr; term_offset:=0;
    end;
  if file_offset=max_print_line then
    begin wlog_cr; file_offset:=0;
    end;
  end;
log_only: begin
  fix_log_offset(s);
  wlog(xchr[s]); incr(file_offset);
  if file_offset=max_print_line then print_ln;
  end;
term_only: begin
  fix_term_offset(s);
  wterm_char(s); incr(term_offset);
  if term_offset=max_print_line then print_ln;
  end;
no_print: do_nothing;
pseudo: if tally<trick_count then trick_buf[tally mod error_line]:=s;
new_string: begin if pool_ptr<pool_size then append_char(s);
  end; {we drop characters if the string space is full}
othercases write(write_file[selector],xchr[s])
endcases;@/
incr(tally);
exit:end;

@ An entire string is output by calling |print|. Note that if we are outputting
the single standard ASCII character \.c, we could call |print("c")|, since
|"c"=99| is the number of a single-character string, as explained above. But
|print_char("c")| is quicker, so \TeX\ goes directly to the |print_char|
routine when it knows that this is safe. (The present implementation
assumes that it is always safe to print a visible ASCII character.)
@^system dependencies@>

The first 256 entries above the 17th unicode plane are used for a
special trick: when \TeX\ has to print items in that range, it will
instead print the character that results from substracting @"110000
from that value. This allows byte-oriented output to things like
\.{\\specials} and \.{\\pdfliterals}. Todo: Perhaps it would be useful
to do the same substraction while typesetting.

@d print_lc_hex(#)==l:=#;
   if l<10 then print_char(l+"0") else print_char(l-10+"a");

@<Basic print...@>=
function pool_to_unichar(@!t:pool_pointer):ASCII_code;
var a,result:@!ASCII_code; {a utf char}
b:@!quarterword; { a utf nibble}
begin
    b := str_pool[t];
    if b<=@"7F then
      a := b
    else if b>=@"F0 then begin
          a := (b-@"F0) * 64;
          b := str_pool[t+1];
          a := (a + (b-128)) * 64;
          b := str_pool[t+2];
          a := (a + (b-128)) * 64;
          b := str_pool[t+3];
          a := a + (b-128);
      end
    else if b>=@"E0 then begin
          a := (b-@"E0) * 64;
          b := str_pool[t+1];
          a := (a + (b-128)) * 64;
          b := str_pool[t+2];
          a := a + (b-128);
      end
    else if b>=@"C0 then begin
          a := (b-@"C0) * 64;
          b := str_pool[t+1];
          a := a + (b-128);
      end
    else begin  { NI: this is an encoding error }
          wlog_ln('! Pool contains an invalid utf-8 sequence');
          wterm_ln('! Pool contains an invalid utf-8 sequence');
@.Text line contains...@>
          help2("A funny symbol somehow ended up in the string pool.")@/
           ("Just continue, I'll change it to 0xFFFD.");@/
      deletions_allowed:=false; error; deletions_allowed:=true;
      a:=@"FFFD;
      end;
result := a;
pool_to_unichar := result;
end ;

procedure print(@!s:integer); {prints string |s|}
label exit;
var j:pool_pointer; {current character code position}
@!v:integer; { a unicode char }
begin if s>=str_ptr then s:="???" {this can't happen}
@.???@>
else if s<string_offset then begin
  if s<0 then s:="???" {can't happen}
  else begin
    {TH not sure about this, disabled for now!}
    if (false)and(selector>pseudo) then
      begin print_char(s); return; {internal strings are not expanded}
      end;
    if (@<Character |s| is the current new-line character@>) then
      if selector<pseudo then
        begin print_ln; return;
        end;
    if s<=@"7F then
      print_char(s)
    else if s<=@"7FF then begin
      print_char(@"C0 + (s div @"40));
      print_char(@"80 + (s mod @"40));
      end
    else if s<=@"FFFF then begin
      print_char(@"E0 + (s div @"1000));
      print_char(@"80 + ((s mod @"1000) div @"40));
      print_char(@"80 + ((s mod @"1000) mod @"40));
      end
    else begin
      if s>=@"110000 then
            print_char(s-@"110000)
      else begin
        print_char(@"F0 + (s div @"40000));
        print_char(@"80 + ((s mod @"40000) div @"1000));
        print_char(@"80 + (((s mod @"40000) mod @"1000) div @"40));
        print_char(@"80 + (((s mod @"40000) mod @"1000) mod @"40));
        end;
      end;
    return;
    end;
  end;
j:=str_start_macro(s);
while j<str_start_macro(s+1) do
  begin { 0x110000 in utf=8: 0xF4 0x90 0x80 0x80 }
    if (str_pool[j]=@"F4)and(j<str_start_macro(s+4))and(str_pool[j+1]=@"90) then begin
          v := (((7*64+63)*64)+ (str_pool[j+2]-128))*64 +(str_pool[j+3]-128);
          print_char(v-@"110000); j := j+4;
      end
    else begin
      print_char(str_pool[j]); incr(j);
    end;
  end;
exit:end;

procedure print_nl(@!s:str_number); {prints string |s| at beginning of line}
begin if ((term_offset>0)and(odd(selector)))or@|
  ((file_offset>0)and(selector>=log_only)) then print_ln;
print(s);
end;

procedure print_nlp; {move to beginning of a line}
begin if ((term_offset>0)and(odd(selector)))or@|
  ((file_offset>0)and(selector>=log_only)) then print_ln;
end;

@ Control sequence names, file names, and strings constructed with
\.{\\string} might contain |ASCII_code| values that can't
be printed using |print_char|. Therefore we use |slow_print| for them:

@<Basic print...@>=
procedure slow_print(@!s:integer); {prints string |s|}
var j:pool_pointer; {current character code position}
begin if (s>=str_ptr) or (s<string_offset) then print(s)
else begin j:=str_start_macro(s);
  while j<str_start_macro(s+1) do
    begin print(so(str_pool[j])); incr(j);
    end;
  end;
end;

@ Here is the very first thing that \TeX\ prints: a headline that identifies
the version number and format package. The |term_offset| variable is temporarily
incorrect, but the discrepancy is not serious since we assume that the banner
and format identifier together will occupy at most |max_print_line|
character positions.

@<Initialize the output...@>=
print_banner;

@ The procedure |print_nl| is like |print|, but it makes sure that the
string appears at the beginning of a new line. (moved)

@<Basic print...@>=

@ The procedure |print_esc| prints a string that is preceded by
the user's escape character (which is usually a backslash).

@<Basic print...@>=
procedure print_esc(@!s:str_number); {prints escape character, then |s|}
var c:integer; {the escape character code}
begin  @<Set variable |c| to the current escape character@>;
if c>=0 then if c<string_offset then print(c);
slow_print(s);
end;

@ An array of digits in the range |0..15| is printed by |print_the_digs|.

@<Basic print...@>=
procedure print_the_digs(@!k:eight_bits);
  {prints |dig[k-1]|$\,\ldots\,$|dig[0]|}
begin while k>0 do
  begin decr(k);
  if dig[k]<10 then print_char("0"+dig[k])
  else print_char("A"-10+dig[k]);
  end;
end;

@ The following procedure, which prints out the decimal representation of a
given integer |n|, has been written carefully so that it works properly
if |n=0| or if |(-n)| would cause overflow. It does not apply |mod| or |div|
to negative arguments, since such operations are not implemented consistently
by all \PASCAL\ compilers.

@<Basic print...@>=
procedure print_int(@!n:longinteger); {prints an integer in decimal form}
var k:0..23; {index to current digit; we assume that $|n|<10^{23}$}
@!m:longinteger; {used to negate |n| in possibly dangerous cases}
begin k:=0;
if n<0 then
  begin print_char("-");
  if n>-100000000 then negate(n)
  else  begin m:=-1-n; n:=m div 10; m:=(m mod 10)+1; k:=1;
    if m<10 then dig[0]:=m
    else  begin dig[0]:=0; incr(n);
      end;
    end;
  end;
repeat dig[k]:=n mod 10; n:=n div 10; incr(k);
until n=0;
print_the_digs(k);
end;

@ Here is a trivial procedure to print two digits; it is usually called with
a parameter in the range |0<=n<=99|.

@p procedure print_two(@!n:integer); {prints two least significant digits}
begin n:=abs(n) mod 100; print_char("0"+(n div 10));
print_char("0"+(n mod 10));
end;

@ Hexadecimal printing of nonnegative integers is accomplished by |print_hex|.

@p procedure print_hex(@!n:integer);
  {prints a positive integer in hexadecimal form}
var k:0..22; {index to current digit; we assume that $0\L n<16^{22}$}
begin k:=0; print_char("""");
repeat dig[k]:=n mod 16; n:=n div 16; incr(k);
until n=0;
print_the_digs(k);
end;

@ Old versions of \TeX\ needed a procedure called |print_ASCII| whose function
is now subsumed by |print|. We retain the old name here as a possible aid to
future software arch\ae ologists.

@d print_ASCII == print
@d print_font_name(#)==begin print(tex_font_name(#)); flush_string; end

@ Roman numerals are produced by the |print_roman_int| routine.  Readers
who like puzzles might enjoy trying to figure out how this tricky code
works; therefore no explanation will be given. Notice that 1990 yields
\.{mcmxc}, not \.{mxm}.

@p procedure print_roman_int(@!n:integer);
label exit;
var j,@!k: pool_pointer; {mysterious indices into |str_pool|}
@!u,@!v: nonnegative_integer; {mysterious numbers}
begin j:=str_start_macro("m2d5c2l5x2v5i"); v:=1000;
loop@+  begin while n>=v do
    begin print_char(so(str_pool[j])); n:=n-v;
    end;
  if n<=0 then return; {nonpositive input produces no output}
  k:=j+2; u:=v div (so(str_pool[k-1])-"0");
  if str_pool[k-1]=si("2") then
    begin k:=k+2; u:=u div (so(str_pool[k-1])-"0");
    end;
  if n+u>=v then
    begin print_char(so(str_pool[k])); n:=n+u;
    end
  else  begin j:=j+2; v:=v div (so(str_pool[j-1])-"0");
    end;
  end;
exit:end;

@ The |print| subroutine will not print a string that is still being
created. The following procedure will.

@p procedure print_current_string; {prints a yet-unmade string}
var j:pool_pointer; {points to current character code}
begin j:=str_start_macro(str_ptr);
while j<pool_ptr do
  begin print_char(so(str_pool[j])); incr(j);
  end;
end;

@ Here is a procedure that asks the user to type a line of input,
assuming that the |selector| setting is either |term_only| or |term_and_log|.
The input is placed into locations |first| through |last-1| of the
|buffer| array, and echoed on the transcript file if appropriate.

This procedure is never called when |interaction<scroll_mode|.

@<Basic print...@>=
procedure prompt_input(s:str_number);
begin wake_up_terminal; print(s); term_input;
end;

@
@p procedure term_input; {gets a line from the terminal}
var k:0..buf_size; {index into |buffer|}
begin update_terminal; {now the user sees the prompt for sure}
if not input_ln(term_in,true)
then fatal_error("End of file on the terminal!");
@.End of file on the terminal@>
term_offset:=0; {the user's line ended with \<\rm return>}
decr(selector); {prepare to echo the input}
if last<>first then for k:=first to last-1 do print(buffer[k]);
print_ln; incr(selector); {restore previous status}
end;

@* \[6] Reporting errors.
When something anomalous is detected, \TeX\ typically does something like this:
$$\vbox{\halign{#\hfil\cr
|print_err("Something anomalous has been detected");|\cr
|help3("This is the first line of my offer to help.")|\cr
|("This is the second line. I'm trying to")|\cr
|("explain the best way for you to proceed.");|\cr
|error;|\cr}}$$
A two-line help message would be given using |help2|, etc.; these informal
helps should use simple vocabulary that complements the words used in the
official error message that was printed. (Outside the U.S.A., the help
messages should preferably be translated into the local vernacular. Each
line of help is at most 60 characters long, in the present implementation,
so that |max_print_line| will not be exceeded.)

The |print_err| procedure supplies a `\.!' before the official message,
and makes sure that the terminal is awake if a stop is going to occur.
The |error| procedure supplies a `\..' after the official message, then it
shows the location of the error; and if |interaction=error_stop_mode|,
it also enters into a dialog with the user, during which time the help
message may be printed.
@^system dependencies@>

@ The global variable |interaction| has four settings, representing increasing
amounts of user interaction:

@d batch_mode=0 {omits all stops and omits terminal output}
@d nonstop_mode=1 {omits all stops}
@d scroll_mode=2 {omits error stops}
@d error_stop_mode=3 {stops at every opportunity to interact}
@d print_err(#)==begin if interaction=error_stop_mode then wake_up_terminal;
  print_nl("! "); print(#);
  last_error:=#; end
@d print_warn(#)==begin if interaction=error_stop_mode then wake_up_terminal;
  if prepend_nl then begin print_nl(""); print_ln end;
  print_nl(#);
  end

@<Glob...@>=
@!interaction:batch_mode..error_stop_mode; {current level of interaction}
@!last_error:str_number;

@ @<Set init...@>=interaction:=error_stop_mode;

@ \TeX\ is careful not to call |error| when the print |selector| setting
might be unusual. The only possible values of |selector| at the time of
error messages are

\yskip\hang|no_print| (when |interaction=batch_mode|
  and |log_file| not yet open);

\hang|term_only| (when |interaction>batch_mode| and |log_file| not yet open);

\hang|log_only| (when |interaction=batch_mode| and |log_file| is open);

\hang|term_and_log| (when |interaction>batch_mode| and |log_file| is open).

@<Initialize the print |selector| based on |interaction|@>=
if interaction=batch_mode then selector:=no_print@+else selector:=term_only

@ A global variable |deletions_allowed| is set |false| if the |get_next|
routine is active when |error| is called; this ensures that |get_next|
and related routines like |get_token| will never be called recursively.
A similar interlock is provided by |set_box_allowed|.
@^recursion@>

The global variable |history| records the worst level of error that
has been detected. It has four possible values: |spotless|, |warning_issued|,
|error_message_issued|, and |fatal_error_stop|.

Another global variable, |error_count|, is increased by one when an
|error| occurs without an interactive dialog, and it is reset to zero at
the end of every paragraph.  If |error_count| reaches 100, \TeX\ decides
that there is no point in continuing further.

@d spotless=0 {|history| value when nothing has been amiss yet}
@d warning_issued=1 {|history| value when |begin_diagnostic| has been called}
@d error_message_issued=2 {|history| value when |error| has been called}
@d fatal_error_stop=3 {|history| value when termination was premature}

@<Glob...@>=
@!deletions_allowed:boolean; {is it safe for |error| to call |get_token|?}
@!set_box_allowed:boolean; {is it safe to do a \.{\\setbox} assignment?}
@!history:spotless..fatal_error_stop; {has the source input been clean so far?}
@!error_count:-1..100; {the number of scrolled errors since the
  last paragraph ended}

@ The value of |history| is initially |fatal_error_stop|, but it will
be changed to |spotless| if \TeX\ survives the initialization process.

@<Set init...@>=
deletions_allowed:=true; set_box_allowed:=true;
error_count:=0; {|history| is initialized elsewhere}

@ Since errors can be detected almost anywhere in \TeX, we want to declare the
error procedures near the beginning of the program. But the error procedures
in turn use some other procedures, which need to be declared |forward|
before we get to |error| itself.

It is possible for |error| to be called recursively if some error arises
when |get_token| is being used to delete a token, and/or if some fatal error
occurs while \TeX\ is trying to fix a non-fatal one. But such recursion
@^recursion@>
is never more than two levels deep.

@<Error handling...@>=
procedure@?normalize_selector; forward;@t\2@>@/
procedure@?get_token; forward;@t\2@>@/
procedure@?term_input; forward;@t\2@>@/
procedure@?show_context; forward;@t\2@>@/
procedure@?begin_file_reading; forward;@t\2@>@/
procedure@?open_log_file; forward;@t\2@>@/
procedure@?close_files_and_terminate; forward;@t\2@>@/
procedure@?clear_for_error_prompt; forward;@t\2@>@/
procedure@?give_err_help; forward;@t\2@>@/
@t\4\hskip-\fontdimen2\font@>@;@+@!debug@+procedure@?debug_help;
  forward;@;@+gubed

@ Individual lines of help are recorded in the array |help_line|, which
contains entries in positions |0..(help_ptr-1)|. They should be printed
in reverse order, i.e., with |help_line[0]| appearing last.

@d hlp1(#)==help_line[0]:=#;@+end
@d hlp2(#)==help_line[1]:=#; hlp1
@d hlp3(#)==help_line[2]:=#; hlp2
@d hlp4(#)==help_line[3]:=#; hlp3
@d hlp5(#)==help_line[4]:=#; hlp4
@d hlp6(#)==help_line[5]:=#; hlp5
@d help0==help_ptr:=0 {sometimes there might be no help}
@d help1==@+begin help_ptr:=1; hlp1 {use this with one help line}
@d help2==@+begin help_ptr:=2; hlp2 {use this with two help lines}
@d help3==@+begin help_ptr:=3; hlp3 {use this with three help lines}
@d help4==@+begin help_ptr:=4; hlp4 {use this with four help lines}
@d help5==@+begin help_ptr:=5; hlp5 {use this with five help lines}
@d help6==@+begin help_ptr:=6; hlp6 {use this with six help lines}

@p
procedure dohelp5 (@!a,b,c,d,e:str_number);
begin
  help5(a)(b)(c)(d)(e);
end;
@#
procedure dohelp4 (@!a,b,c,d:str_number);
begin
  help4(a)(b)(c)(d);
end;
@#
procedure dohelp3 (@!a,b,c:str_number);
begin
  help3(a)(b)(c);
end;
@#
procedure dohelp2 (@!a,b:str_number);
begin
  help2(a)(b);
end;
@#
procedure dohelp1 (@!a:str_number);
begin
  help1(a);
end;
@#
procedure dohelp0;
begin
  help0;
end;
@#
procedure do_print_err (s:str_number);
begin
  print_err(s);
end;

@ @<Glob...@>=
@!help_line:array[0..5] of str_number; {helps for the next |error|}
@!help_ptr:0..6; {the number of help lines present}
@!use_err_help:boolean; {should the |err_help| list be shown?}

@ @<Set init...@>=
help_ptr:=0; use_err_help:=false;

@ The |jump_out| procedure just cuts across all active procedure levels and
goes to |end_of_TEX|. This is the only nontrivial |@!goto| statement in the
whole program. It is used when there is no recovery from a particular error.

Some \PASCAL\ compilers do not implement non-local |goto| statements.
@^system dependencies@>
In such cases the body of |jump_out| should simply be
`|close_files_and_terminate|;\thinspace' followed by a call on some system
procedure that quietly terminates the program.

@<Error hand...@>=
procedure jump_out;
begin goto end_of_TEX;
end;

@ Here now is the general |error| routine.

@<Error hand...@>=
procedure error; {completes the job of error reporting}
label continue,exit;
var c:ASCII_code; {what the user types}
callback_id:integer;
@!s1,@!s2,@!s3,@!s4:integer;
  {used to save global variables when deleting tokens}
@!t:boolean;
begin if history<error_message_issued then history:=error_message_issued;
print_char(".");
callback_id := callback_defined(show_error_hook_callback) ;
if callback_id>0 then t := run_callback(callback_id,'->');
show_context;
if interaction=error_stop_mode then @<Get user's advice and |return|@>;
incr(error_count);
if error_count=100 then
  begin print_nl("(That makes 100 errors; please try again.)");
@.That makes 100 errors...@>
  history:=fatal_error_stop; jump_out;
  end;
@<Put help message on the transcript file@>;
exit:end;

@ @<Get user's advice...@>=
loop@+begin continue: clear_for_error_prompt; prompt_input("? ");
@.?\relax@>
  if last=first then return;
  c:=buffer[first];
  if c>="a" then c:=c+"A"-"a"; {convert to uppercase}
  @<Interpret code |c| and |return| if done@>;
  end

@ It is desirable to provide an `\.E' option here that gives the user
an easy way to return from \TeX\ to the system editor, with the offending
line ready to be edited. But such an extension requires some system
wizardry, so the present implementation simply types out the name of the
file that should be
edited and the relevant line number.
@^system dependencies@>

There is a secret `\.D' option available when the debugging routines haven't
been commented~out.
@^debugging@>

@<Interpret code |c| and |return| if done@>=
case c of
"0","1","2","3","4","5","6","7","8","9": if deletions_allowed then
  @<Delete \(c)|c-"0"| tokens and |goto continue|@>;
@t\4\4@>@;@+@!debug "D": begin debug_help; goto continue;@+end;@+gubed@/
"E": if base_ptr>0 then
  begin print_nl("You want to edit file ");
@.You want to edit file x@>
  slow_print(input_stack[base_ptr].name_field);
  print(" at line "); print_int(line);
  interaction:=scroll_mode; jump_out;
  end;
"H": @<Print the help information and |goto continue|@>;
"I":@<Introduce new material from the terminal and |return|@>;
"Q","R","S":@<Change the interaction level and |return|@>;
"X":begin interaction:=scroll_mode; jump_out;
  end;
othercases do_nothing
endcases;@/
@<Print the menu of available options@>

@ @<Print the menu...@>=
begin print("Type <return> to proceed, S to scroll future error messages,");@/
@.Type <return> to proceed...@>
print_nl("R to run without stopping, Q to run quietly,");@/
print_nl("I to insert something, ");
if base_ptr>0 then print("E to edit your file,");
if deletions_allowed then
  print_nl("1 or ... or 9 to ignore the next 1 to 9 tokens of input,");
print_nl("H for help, X to quit.");
end

@ Here the author of \TeX\ apologizes for making use of the numerical
relation between |"Q"|, |"R"|, |"S"|, and the desired interaction settings
|batch_mode|, |nonstop_mode|, |scroll_mode|.
@^Knuth, Donald Ervin@>

@<Change the interaction...@>=
begin error_count:=0; interaction:=batch_mode+c-"Q";
print("OK, entering ");
case c of
"Q":begin print_esc("batchmode"); decr(selector);
  end;
"R":print_esc("nonstopmode");
"S":print_esc("scrollmode");
end; {there are no other cases}
print("..."); print_ln; update_terminal; return;
end

@ When the following code is executed, |buffer[(first+1)..(last-1)]| may
contain the material inserted by the user; otherwise another prompt will
be given. In order to understand this part of the program fully, you need
to be familiar with \TeX's input stacks.

@<Introduce new material...@>=
begin begin_file_reading; {enter a new syntactic level for terminal input}
{now |state=mid_line|, so an initial blank space will count as a blank}
if last>first+1 then
  begin loc:=first+1; buffer[first]:=" ";
  end
else  begin prompt_input("insert>"); loc:=first;
@.insert>@>
  end;
first:=last;
cur_input.limit_field:=last-1; {no |end_line_char| ends this line}
return;
end

@ We allow deletion of up to 99 tokens at a time.

@<Delete \(c)|c-"0"| tokens...@>=
begin s1:=cur_tok; s2:=cur_cmd; s3:=cur_chr; s4:=align_state;
align_state:=1000000; OK_to_interrupt:=false;
if (last>first+1) and (buffer[first+1]>="0")and(buffer[first+1]<="9") then
  c:=c*10+buffer[first+1]-"0"*11
else c:=c-"0";
while c>0 do
  begin get_token; {one-level recursive call of |error| is possible}
  decr(c);
  end;
cur_tok:=s1; cur_cmd:=s2; cur_chr:=s3; align_state:=s4; OK_to_interrupt:=true;
help2("I have just deleted some text, as you asked.")@/
("You can now delete more, or insert, or whatever.");
show_context; goto continue;
end

@ @<Print the help info...@>=
begin if use_err_help then
  begin give_err_help; use_err_help:=false;
  end
else  begin if help_ptr=0 then
    help2("Sorry, I don't know how to help in this situation.")@/
    @t\kern1em@>("Maybe you should try asking a human?");
  repeat decr(help_ptr); print(help_line[help_ptr]); print_ln;
  until help_ptr=0;
  end;
help4("Sorry, I already gave what help I could...")@/
  ("Maybe you should try asking a human?")@/
  ("An error might have occurred before I noticed any problems.")@/
  ("``If all else fails, read the instructions.''");@/
goto continue;
end

@ @<Put help message on the transcript file@>=
if interaction>batch_mode then decr(selector); {avoid terminal output}
if use_err_help then
  begin print_ln; give_err_help;
  end
else while help_ptr>0 do
  begin decr(help_ptr); print_nl(help_line[help_ptr]);
  end;
print_ln;
if interaction>batch_mode then incr(selector); {re-enable terminal output}
print_ln

@ A dozen or so error messages end with a parenthesized integer, so we
save a teeny bit of program space by declaring the following procedure:

@p procedure int_error(@!n:integer);
begin print(" ("); print_int(n); print_char(")"); error;
end;

@ In anomalous cases, the print selector might be in an unknown state;
the following subroutine is called to fix things just enough to keep
running a bit longer.

@p procedure normalize_selector;
begin if log_opened then selector:=term_and_log
else selector:=term_only;
if job_name=0 then open_log_file;
if interaction=batch_mode then decr(selector);
end;

@ The following procedure prints \TeX's last words before dying.

@d succumb==begin if interaction=error_stop_mode then
    interaction:=scroll_mode; {no more interaction}
  if log_opened then error;
  @!debug if interaction>batch_mode then debug_help;@+gubed@;@/
  history:=fatal_error_stop; jump_out; {irrecoverable error}
  end

@<Error hand...@>=
procedure fatal_error(@!s:str_number); {prints |s|, and that's it}
begin normalize_selector;@/
print_err("Emergency stop"); help1(s); succumb;
@.Emergency stop@>
end;

@ Here is the most dreaded error message.

@<Error hand...@>=
procedure lua_norm_error(@!s:str_number); {lua found a problem}
var saved_new_line_char: integer;
begin
saved_new_line_char:=new_line_char;
new_line_char:=10;
print_err("LuaTeX error "); print(s);
help2("The lua interpreter ran into a problem, so the")@/
  ("remainder of this lua chunk will be ignored.");
error;
new_line_char:=saved_new_line_char;
end;

procedure lua_fatal_error(@!s:str_number); {lua found a problem}
begin new_line_char:=10; normalize_selector;
print_err("LuaTeX fatal error "); print(s);
succumb;
end;

procedure overflow(@!s:str_number;@!n:integer); {stop due to finiteness}
begin normalize_selector;
print_err("TeX capacity exceeded, sorry [");
@.TeX capacity exceeded ...@>
print(s); print_char("="); print_int(n); print_char("]");
help2("If you really absolutely need more capacity,")@/
  ("you can ask a wizard to enlarge me.");
succumb;
end;

procedure overflow_ocp_buf_size;
begin
overflow("ocp_buf_size",ocp_buf_size);
end;

procedure overflow_ocp_stack_size;
begin
overflow("ocp_stack_size",ocp_stack_size);
end;


@ The program might sometime run completely amok, at which point there is
no choice but to stop. If no previous error has been detected, that's bad
news; a message is printed that is really intended for the \TeX\
maintenance person instead of the user (unless the user has been
particularly diabolical).  The index entries for `this can't happen' may
help to pinpoint the problem.
@^dry rot@>

@<Error hand...@>=
procedure confusion(@!s:str_number);
  {consistency check violated; |s| tells where}
begin normalize_selector;
if history<error_message_issued then
  begin print_err("This can't happen ("); print(s); print_char(")");
@.This can't happen@>
  help1("I'm broken. Please show this to someone who can fix can fix");
  end
else  begin print_err("I can't go on meeting you like this");
@.I can't go on...@>
  help2("One of your faux pas seems to have wounded me deeply...")@/
    ("in fact, I'm barely conscious. Please fix it and try again.");
  end;
succumb;
end;

@ Users occasionally want to interrupt \TeX\ while it's running.
If the \PASCAL\ runtime system allows this, one can implement
a routine that sets the global variable |interrupt| to some nonzero value
when such an interrupt is signalled. Otherwise there is probably at least
a way to make |interrupt| nonzero using the \PASCAL\ debugger.
@^system dependencies@>
@^debugging@>

@<Global...@>=
@!interrupt:integer; {should \TeX\ pause for instructions?}
@!OK_to_interrupt:boolean; {should interrupts be observed?}
@!static_int_base:integer; {C version of |int_base|}
@!static_glue_base:integer; {C version of |glue_base|}
@!static_dimen_base:integer; {C version of |dimen_base|}
@!static_local_base:integer; {C version of |local_base|}

@ @p procedure check_interrupt;
begin
if interrupt<>0 then pause_for_instructions;
end;


@ @<Set init...@>=
interrupt:=0; OK_to_interrupt:=true;

@ When an interrupt has been detected, the program goes into its
highest interaction level and lets the user have nearly the full flexibility of
the |error| routine.  \TeX\ checks for interrupts only at times when it is
safe to do this.

@p procedure pause_for_instructions;
begin if OK_to_interrupt then
  begin interaction:=error_stop_mode;
  if (selector=log_only)or(selector=no_print) then
    incr(selector);
  print_err("Interruption");
@.Interruption@>
  help3("You rang?")@/
  ("Try to insert some instructions for me (e.g.,`I\showlists'),")@/
  ("unless you just want to quit by typing `X'.");
  deletions_allowed:=false; error; deletions_allowed:=true;
  interrupt:=0;
  end;
end;

@* \[7] Arithmetic with scaled dimensions.
The principal computations performed by \TeX\ are done entirely in terms of
integers less than $2^{31}$ in magnitude; and divisions are done only when both
dividend and divisor are nonnegative. Thus, the arithmetic specified in this
program can be carried out in exactly the same way on a wide variety of
computers, including some small ones. Why? Because the arithmetic
calculations need to be spelled out precisely in order to guarantee that
\TeX\ will produce identical output on different machines. If some
quantities were rounded differently in different implementations, we would
find that line breaks and even page breaks might occur in different places.
Hence the arithmetic of \TeX\ has been designed with care, and systems that
claim to be implementations of \TeX82 should follow precisely the
@:TeX82}{\TeX82@>
calculations as they appear in the present program.

(Actually there are three places where \TeX\ uses |div| with a possibly negative
numerator. These are harmless; see |div| in the index. Also if the user
sets the \.{\\time} or the \.{\\year} to a negative value, some diagnostic
information will involve negative-numerator division. The same remarks
apply for |mod| as well as for |div|.)

@ Here is a routine that calculates half of an integer, using an
unambiguous convention with respect to signed odd numbers.

@p function half(@!x:integer):integer;
begin if odd(x) then half:=(x+1) div 2
else half:=x @!div 2;
end;

@ Fixed-point arithmetic is done on {\sl scaled integers\/} that are multiples
of $2^{-16}$. In other words, a binary point is assumed to be sixteen bit
positions from the right end of a binary computer word.

@d unity == @'200000 {$2^{16}$, represents 1.00000}
@d two == @'400000 {$2^{17}$, represents 2.00000}

@<Types...@>=
@!scaled = integer; {this type is used for scaled integers}
@!nonnegative_integer=0..@'17777777777; {$0\L x<2^{31}$}
@!small_number=0..63; {this type is self-explanatory}

@ The following function is used to create a scaled integer from a given decimal
fraction $(.d_0d_1\ldots d_{k-1})$, where |0<=k<=17|. The digit $d_i$ is
given in |dig[i]|, and the calculation produces a correctly rounded result.

@p function round_decimals(@!k:small_number) : scaled;
  {converts a decimal fraction}
var a:integer; {the accumulator}
begin a:=0;
while k>0 do
  begin decr(k); a:=(a+dig[k]*two) div 10;
  end;
round_decimals:=(a+1) div 2;
end;

@ Conversely, here is a procedure analogous to |print_int|. If the output
of this procedure is subsequently read by \TeX\ and converted by the
|round_decimals| routine above, it turns out that the original value will
be reproduced exactly; the ``simplest'' such decimal number is output,
but there is always at least one digit following the decimal point.

The invariant relation in the \&{repeat} loop is that a sequence of
decimal digits yet to be printed will yield the original number if and only if
they form a fraction~$f$ in the range $s-\delta\L10\cdot2^{16}f<s$.
We can stop if and only if $f=0$ satisfies this condition; the loop will
terminate before $s$ can possibly become zero.

@p procedure print_scaled(@!s:scaled); {prints scaled real, rounded to five
  digits}
var delta:scaled; {amount of allowable inaccuracy}
begin if s<0 then
  begin print_char("-"); negate(s); {print the sign, if negative}
  end;
print_int(s div unity); {print the integer part}
print_char(".");
s:=10*(s mod unity)+5; delta:=10;
repeat if delta>unity then s:=s+@'100000-50000; {round the last digit}
print_char("0"+(s div unity)); s:=10*(s mod unity); delta:=delta*10;
until s<=delta;
end;

@ Physical sizes that a \TeX\ user specifies for portions of documents are
represented internally as scaled points. Thus, if we define an `sp' (scaled
@^sp@>
point) as a unit equal to $2^{-16}$ printer's points, every dimension
inside of \TeX\ is an integer number of sp. There are exactly
4,736,286.72 sp per inch.  Users are not allowed to specify dimensions
larger than $2^{30}-1$ sp, which is a distance of about 18.892 feet (5.7583
meters); two such quantities can be added without overflow on a 32-bit
computer.

The present implementation of \TeX\ does not check for overflow when
@^overflow in arithmetic@>
dimensions are added or subtracted. This could be done by inserting a
few dozen tests of the form `\ignorespaces|if x>=@'10000000000 then
@t\\{report\_overflow}@>|', but the chance of overflow is so remote that
such tests do not seem worthwhile.

\TeX\ needs to do only a few arithmetic operations on scaled quantities,
other than addition and subtraction, and the following subroutines do most of
the work. A single computation might use several subroutine calls, and it is
desirable to avoid producing multiple error messages in case of arithmetic
overflow; so the routines set the global variable |arith_error| to |true|
instead of reporting errors directly to the user. Another global variable,
|remainder|, holds the remainder after a division.

@<Glob...@>=
@!arith_error:boolean; {has arithmetic overflow occurred recently?}
@!remainder:scaled; {amount subtracted to get an exact division}

@ The first arithmetical subroutine we need computes $nx+y$, where |x|
and~|y| are |scaled| and |n| is an integer. We will also use it to
multiply integers.

@d nx_plus_y(#)==mult_and_add(#,@'7777777777)
@d mult_integers(#)==mult_and_add(#,0,@'17777777777)

@p function mult_and_add(@!n:integer;@!x,@!y,@!max_answer:scaled):scaled;
begin if n<0 then
  begin negate(x); negate(n);
  end;
if n=0 then mult_and_add:=y
else if ((x<=(max_answer-y) div n)and(-x<=(max_answer+y) div n)) then
  mult_and_add:=n*x+y
else  begin arith_error:=true; mult_and_add:=0;
  end;
end;

@ We also need to divide scaled dimensions by integers.

@p function x_over_n(@!x:scaled;@!n:integer):scaled;
var negative:boolean; {should |remainder| be negated?}
begin negative:=false;
if n=0 then
  begin arith_error:=true; x_over_n:=0; remainder:=x;
  end
else  begin if n<0 then
    begin negate(x); negate(n); negative:=true;
    end;
  if x>=0 then
    begin x_over_n:=x div n; remainder:=x mod n;
    end
  else  begin x_over_n:=-((-x) div n); remainder:=-((-x) mod n);
    end;
  end;
if negative then negate(remainder);
end;

@ Then comes the multiplication of a scaled number by a fraction |n/d|,
where |n| and |d| are nonnegative integers |<=@t$2^{16}$@>| and |d| is
positive. It would be too dangerous to multiply by~|n| and then divide
by~|d|, in separate operations, since overflow might well occur; and it
would be too inaccurate to divide by |d| and then multiply by |n|. Hence
this subroutine simulates 1.5-precision arithmetic.

@p function xn_over_d(@!x:scaled; @!n,@!d:integer):scaled;
var positive:boolean; {was |x>=0|?}
@!t,@!u,@!v:nonnegative_integer; {intermediate quantities}
begin if x>=0 then positive:=true
else  begin negate(x); positive:=false;
  end;
t:=(x mod @'100000)*n;
u:=(x div @'100000)*n+(t div @'100000);
v:=(u mod d)*@'100000 + (t mod @'100000);
if u div d>=@'100000 then arith_error:=true
else u:=@'100000*(u div d) + (v div d);
if positive then
  begin xn_over_d:=u; remainder:=v mod d;
  end
else  begin xn_over_d:=-u; remainder:=-(v mod d);
  end;
end;

@ The next subroutine is used to compute the ``badness'' of glue, when a
total~|t| is supposed to be made from amounts that sum to~|s|.  According
to {\sl The \TeX book}, the badness of this situation is $100(t/s)^3$;
however, badness is simply a heuristic, so we need not squeeze out the
last drop of accuracy when computing it. All we really want is an
approximation that has similar properties.
@:TeXbook}{\sl The \TeX book@>

The actual method used to compute the badness is easier to read from the
program than to describe in words. It produces an integer value that is a
reasonably close approximation to $100(t/s)^3$, and all implementations
of \TeX\ should use precisely this method. Any badness of $2^{13}$ or more is
treated as infinitely bad, and represented by 10000.

It is not difficult to prove that $$\hbox{|badness(t+1,s)>=badness(t,s)
>=badness(t,s+1)|}.$$ The badness function defined here is capable of
computing at most 1095 distinct values, but that is plenty.

@d inf_bad = 10000 {infinitely bad value}

@p function badness(@!t,@!s:scaled):halfword; {compute badness, given |t>=0|}
var r:integer; {approximation to $\alpha t/s$, where $\alpha^3\approx
  100\cdot2^{18}$}
begin if t=0 then badness:=0
else if s<=0 then badness:=inf_bad
else  begin if t<=7230584 then  r:=(t*297) div s {$297^3=99.94\times2^{18}$}
  else if s>=1663497 then r:=t div (s div 297)
  else r:=t;
  if r>1290 then badness:=inf_bad {$1290^3<2^{31}<1291^3$}
  else badness:=(r*r*r+@'400000) div @'1000000;
  end; {that was $r^3/2^{18}$, rounded to the nearest integer}
end;

@ When \TeX\ ``packages'' a list into a box, it needs to calculate the
proportionality ratio by which the glue inside the box should stretch
or shrink. This calculation does not affect \TeX's decision making,
so the precise details of rounding, etc., in the glue calculation are not
of critical importance for the consistency of results on different computers.

We shall use the type |glue_ratio| for such proportionality ratios.
A glue ratio should take the same amount of memory as an
|integer| (usually 32 bits) if it is to blend smoothly with \TeX's
other data structures. Thus |glue_ratio| should be equivalent to
|short_real| in some implementations of \PASCAL. Alternatively,
it is possible to deal with glue ratios using nothing but fixed-point
arithmetic; see {\sl TUGboat \bf3},1 (March 1982), 10--27. (But the
routines cited there must be modified to allow negative glue ratios.)
@^system dependencies@>

@d set_glue_ratio_zero(#) == #:=0.0 {store the representation of zero ratio}
@d set_glue_ratio_one(#) == #:=1.0 {store the representation of unit ratio}
@d float(#) == # {convert from |glue_ratio| to type |real|}
@d unfloat(#) == # {convert from |real| to type |glue_ratio|}
@d float_constant(#) == #.0 {convert |integer| constant to |real|}

@<Types...@>=
@!glue_ratio=real; {one-word representation of a glue expansion factor}

@* \[7b] Random numbers.

\font\tenlogo=logo10 % font used for the METAFONT logo
\def\MP{{\tenlogo META}\-{\tenlogo POST}}

This section is (almost) straight from MetaPost. I had to change
the types (use |integer| instead of |fraction|), but that should
not have any influence on the actual calculations (the original
comments refer to quantities like |fraction_four| ($2^{30}$), and
that is the same as the numeric representation of |max_dimen|).

I've copied the low-level variables and routines that are needed, but
only those (e.g. |m_log|), not the accompanying ones like |m_exp|. Most
of the following low-level numeric routines are only needed within the
calculation of |norm_rand|. I've been forced to rename |make_fraction|
to |make_frac| because TeX already has a routine by that name with
a wholly different function (it creates a |fraction_noad| for math
typesetting) -- Taco

And now let's complete our collection of numeric utility routines
by considering random number generation.
\MP\ generates pseudo-random numbers with the additive scheme recommended
in Section 3.6 of {\sl The Art of Computer Programming}; however, the
results are random fractions between 0 and |fraction_one-1|, inclusive.

There's an auxiliary array |randoms| that contains 55 pseudo-random
fractions. Using the recurrence $x_n=(x_{n-55}-x_{n-31})\bmod 2^{28}$,
we generate batches of 55 new $x_n$'s at a time by calling |new_randoms|.
The global variable |j_random| tells which element has most recently
been consumed.

@<Glob...@>=
@!randoms:array[0..54] of integer; {the last 55 random values generated}
@!j_random:0..54; {the number of unused |randoms|}
@!random_seed:scaled; {the default random seed}

@ A small bit of metafont is needed.

@d fraction_half==@'1000000000 {$2^{27}$, represents 0.50000000}
@d fraction_one==@'2000000000 {$2^{28}$, represents 1.00000000}
@d fraction_four==@'10000000000 {$2^{30}$, represents 4.00000000}
@d el_gordo == @'17777777777 {$2^{31}-1$, the largest value that \MP\ likes}
@d halfp(#)==(#) div 2
@d double(#) == #:=#+# {multiply a variable by two}

@ The |make_frac| routine produces the |fraction| equivalent of
|p/q|, given integers |p| and~|q|; it computes the integer
$f=\lfloor2^{28}p/q+{1\over2}\rfloor$, when $p$ and $q$ are
positive. If |p| and |q| are both of the same scaled type |t|,
the ``type relation'' |make_frac(t,t)=fraction| is valid;
and it's also possible to use the subroutine ``backwards,'' using
the relation |make_frac(t,fraction)=t| between scaled types.

If the result would have magnitude $2^{31}$ or more, |make_frac|
sets |arith_error:=true|. Most of \MP's internal computations have
been designed to avoid this sort of error.

If this subroutine were programmed in assembly language on a typical
machine, we could simply compute |(@t$2^{28}$@>*p)div q|, since a
double-precision product can often be input to a fixed-point division
instruction. But when we are restricted to \PASCAL\ arithmetic it
is necessary either to resort to multiple-precision maneuvering
or to use a simple but slow iteration. The multiple-precision technique
would be about three times faster than the code adopted here, but it
would be comparatively long and tricky, involving about sixteen
additional multiplications and divisions.

This operation is part of \MP's ``inner loop''; indeed, it will
consume nearly 10\pct! of the running time (exclusive of input and output)
if the code below is left unchanged. A machine-dependent recoding
will therefore make \MP\ run faster. The present implementation
is highly portable, but slow; it avoids multiplication and division
except in the initial stage. System wizards should be careful to
replace it with a routine that is guaranteed to produce identical
results in all cases.
@^system dependencies@>

As noted below, a few more routines should also be replaced by machine-dependent
code, for efficiency. But when a procedure is not part of the ``inner loop,''
such changes aren't advisable; simplicity and robustness are
preferable to trickery, unless the cost is too high.
@^inner loop@>

@p function make_frac(@!p,@!q:integer):integer;
var @!f:integer; {the fraction bits, with a leading 1 bit}
@!n:integer; {the integer part of $\vert p/q\vert$}
@!negative:boolean; {should the result be negated?}
@!be_careful:integer; {disables certain compiler optimizations}
begin if p>=0 then negative:=false
else  begin negate(p); negative:=true;
  end;
if q<=0 then
  begin debug if q=0 then confusion("/");@;@+gubed@;@/
@:this can't happen /}{\quad \./@>
  negate(q); negative:=not negative;
  end;
n:=p div q; p:=p mod q;
if n>=8 then
  begin arith_error:=true;
  if negative then make_frac:=-el_gordo@+else make_frac:=el_gordo;
  end
else  begin n:=(n-1)*fraction_one;
  @<Compute $f=\lfloor 2^{28}(1+p/q)+{1\over2}\rfloor$@>;
  if negative then make_frac:=-(f+n)@+else make_frac:=f+n;
  end;
end;

@ The |repeat| loop here preserves the following invariant relations
between |f|, |p|, and~|q|:
(i)~|0<=p<q|; (ii)~$fq+p=2^k(q+p_0)$, where $k$ is an integer and
$p_0$ is the original value of~$p$.

Notice that the computation specifies
|(p-q)+p| instead of |(p+p)-q|, because the latter could overflow.
Let us hope that optimizing compilers do not miss this point; a
special variable |be_careful| is used to emphasize the necessary
order of computation. Optimizing compilers should keep |be_careful|
in a register, not store it in memory.
@^inner loop@>

@<Compute $f=\lfloor 2^{28}(1+p/q)+{1\over2}\rfloor$@>=
f:=1;
repeat be_careful:=p-q; p:=be_careful+p;
if p>=0 then f:=f+f+1
else  begin double(f); p:=p+q;
  end;
until f>=fraction_one;
be_careful:=p-q;
if be_careful+p>=0 then incr(f)

@

@p function take_frac(@!q:integer;@!f:integer):integer;
var @!p:integer; {the fraction so far}
@!negative:boolean; {should the result be negated?}
@!n:integer; {additional multiple of $q$}
@!be_careful:integer; {disables certain compiler optimizations}
begin @<Reduce to the case that |f>=0| and |q>0|@>;
if f<fraction_one then n:=0
else  begin n:=f div fraction_one; f:=f mod fraction_one;
  if q<=el_gordo div n then n:=n*q
  else  begin arith_error:=true; n:=el_gordo;
    end;
  end;
f:=f+fraction_one;
@<Compute $p=\lfloor qf/2^{28}+{1\over2}\rfloor-q$@>;
be_careful:=n-el_gordo;
if be_careful+p>0 then
  begin arith_error:=true; n:=el_gordo-p;
  end;
if negative then take_frac:=-(n+p)
else take_frac:=n+p;
end;

@ @<Reduce to the case that |f>=0| and |q>0|@>=
if f>=0 then negative:=false
else  begin negate(f); negative:=true;
  end;
if q<0 then
  begin negate(q); negative:=not negative;
  end;

@ The invariant relations in this case are (i)~$\lfloor(qf+p)/2^k\rfloor
=\lfloor qf_0/2^{28}+{1\over2}\rfloor$, where $k$ is an integer and
$f_0$ is the original value of~$f$; (ii)~$2^k\L f<2^{k+1}$.
@^inner loop@>

@<Compute $p=\lfloor qf/2^{28}+{1\over2}\rfloor-q$@>=
p:=fraction_half; {that's $2^{27}$; the invariants hold now with $k=28$}
if q<fraction_four then
  repeat if odd(f) then p:=halfp(p+q)@+else p:=halfp(p);
  f:=halfp(f);
  until f=1
else  repeat if odd(f) then p:=p+halfp(q-p)@+else p:=halfp(p);
  f:=halfp(f);
  until f=1

@ The subroutines for logarithm and exponential involve two tables.
The first is simple: |two_to_the[k]| equals $2^k$. The second involves
a bit more calculation, which the author claims to have done correctly:
|spec_log[k]| is $2^{27}$ times $\ln\bigl(1/(1-2^{-k})\bigr)=
2^{-k}+{1\over2}2^{-2k}+{1\over3}2^{-3k}+\cdots\,$, rounded to the
nearest integer.

@<Glob...@>=
@!two_to_the:array[0..30] of integer; {powers of two}
@!spec_log:array[1..28] of integer; {special logarithms}


@ @<Set init...@>=
two_to_the[0]:=1;
for k:=1 to 30 do two_to_the[k]:=2*two_to_the[k-1];
spec_log[1]:=93032640;
spec_log[2]:=38612034;
spec_log[3]:=17922280;
spec_log[4]:=8662214;
spec_log[5]:=4261238;
spec_log[6]:=2113709;
spec_log[7]:=1052693;
spec_log[8]:=525315;
spec_log[9]:=262400;
spec_log[10]:=131136;
spec_log[11]:=65552;
spec_log[12]:=32772;
spec_log[13]:=16385;
for k:=14 to 27 do spec_log[k]:=two_to_the[27-k];
spec_log[28]:=1;

@

@p function m_log(@!x:integer):integer;
var @!y,@!z:integer; {auxiliary registers}
@!k:integer; {iteration counter}
begin if x<=0 then @<Handle non-positive logarithm@>
else  begin y:=1302456956+4-100; {$14\times2^{27}\ln2\approx1302456956.421063$}
  z:=27595+6553600; {and $2^{16}\times .421063\approx 27595$}
  while x<fraction_four do
    begin double(x); y:=y-93032639; z:=z-48782;
    end; {$2^{27}\ln2\approx 93032639.74436163$
      and $2^{16}\times.74436163\approx 48782$}
  y:=y+(z div unity); k:=2;
  while x>fraction_four+4 do
    @<Increase |k| until |x| can be multiplied by a
      factor of $2^{-k}$, and adjust $y$ accordingly@>;
  m_log:=y div 8;
  end;
end;

@ @<Increase |k| until |x| can...@>=
begin z:=((x-1) div two_to_the[k])+1; {$z=\lceil x/2^k\rceil$}
while x<fraction_four+z do
  begin z:=halfp(z+1); k:=k+1;
  end;
y:=y+spec_log[k]; x:=x-z;
end

@ @<Handle non-positive logarithm@>=
begin print_err("Logarithm of ");
@.Logarithm...replaced by 0@>
print_scaled(x); print(" has been replaced by 0");
help2("Since I don't take logs of non-positive numbers,")@/
  ("I'm zeroing this one. Proceed, with fingers crossed.");
error; m_log:=0;
end

@ The following somewhat different subroutine tests rigorously if $ab$ is
greater than, equal to, or less than~$cd$,
given integers $(a,b,c,d)$. In most cases a quick decision is reached.
The result is $+1$, 0, or~$-1$ in the three respective cases.

@d return_sign(#)==begin ab_vs_cd:=#; return;
  end

@p function ab_vs_cd(@!a,b,c,d:integer):integer;
label exit;
var @!q,@!r:integer; {temporary registers}
begin @<Reduce to the case that |a,c>=0|, |b,d>0|@>;
loop@+  begin q := a div d; r := c div b;
  if q<>r then begin
    if q>r then return_sign(1)@+else return_sign(-1);
    end;
  q := a mod d; r := c mod b;
  if r=0 then begin
    if q=0 then return_sign(0)@+else return_sign(1);
    end;
  if q=0 then return_sign(-1);
  a:=b; b:=q; c:=d; d:=r;
  end; {now |a>d>0| and |c>b>0|}
exit:end;

@ @<Reduce to the case that |a...@>=
if a<0 then
  begin negate(a); negate(b);
  end;
if c<0 then
  begin negate(c); negate(d);
  end;
if d<=0 then
  begin if b>=0 then begin
    if ((a=0)or(b=0))and((c=0)or(d=0)) then return_sign(0)
    else return_sign(1);
    end;
  if d=0 then begin
    if a=0 then return_sign(0)@+else return_sign(-1);
    end;
  q:=a; a:=c; c:=q; q:=-b; b:=-d; d:=q;
  end
else if b<=0 then
  begin if b<0 then if a>0 then return_sign(-1);
  if c=0 then return_sign(0) else return_sign(-1);
  end

@ To consume a random integer, the program below will say `|next_random|'
and then it will fetch |randoms[j_random]|.

@d next_random==if j_random=0 then new_randoms
  else decr(j_random)

@p procedure new_randoms;
var @!k:0..54; {index into |randoms|}
@!x:integer; {accumulator}
begin for k:=0 to 23 do
  begin x:=randoms[k]-randoms[k+31];
  if x<0 then x:=x+fraction_one;
  randoms[k]:=x;
  end;
for k:=24 to 54 do
  begin x:=randoms[k]-randoms[k-24];
  if x<0 then x:=x+fraction_one;
  randoms[k]:=x;
  end;
j_random:=54;
end;

@ To initialize the |randoms| table, we call the following routine.

@p procedure init_randoms(@!seed:integer);
var @!j,@!jj,@!k:integer; {more or less random integers}
@!i:0..54; {index into |randoms|}
begin j:=abs(seed);
while j>=fraction_one do j:=halfp(j);
k:=1;
for i:=0 to 54 do
  begin jj:=k; k:=j-k; j:=jj;
  if k<0 then k:=k+fraction_one;
  randoms[(i*21)mod 55]:=j;
  end;
new_randoms; new_randoms; new_randoms; {``warm up'' the array}
end;

@ To produce a uniform random number in the range |0<=u<x| or |0>=u>x|
or |0=u=x|, given a |scaled| value~|x|, we proceed as shown here.

Note that the call of |take_frac| will produce the values 0 and~|x|
with about half the probability that it will produce any other particular
values between 0 and~|x|, because it rounds its answers.

@p function unif_rand(@!x:integer):integer;
var @!y:integer; {trial value}
begin next_random; y:=take_frac(abs(x),randoms[j_random]);
if y=abs(x) then unif_rand:=0
else if x>0 then unif_rand:=y
else unif_rand:=-y;
end;

@ Finally, a normal deviate with mean zero and unit standard deviation
can readily be obtained with the ratio method (Algorithm 3.4.1R in
{\sl The Art of Computer Programming\/}).

@p function norm_rand:integer;
var @!x,@!u,@!l:integer; {what the book would call $2^{16}X$, $2^{28}U$,
  and $-2^{24}\ln U$}
begin repeat
  repeat next_random;
  x:=take_frac(112429,randoms[j_random]-fraction_half);
    {$2^{16}\sqrt{8/e}\approx 112428.82793$}
  next_random; u:=randoms[j_random];
  until abs(x)<u;
x:=make_frac(x,u);
l:=139548960-m_log(u); {$2^{24}\cdot12\ln2\approx139548959.6165$}
until ab_vs_cd(1024,l,x,x)>=0;
norm_rand:=x;
end;

@* \[8] Packed data.
In order to make efficient use of storage space, \TeX\ bases its major data
structures on a |memory_word|, which contains either a (signed) integer,
possibly scaled, or a (signed) |glue_ratio|, or a small number of
fields that are one half or one quarter of the size used for storing
integers.

If |x| is a variable of type |memory_word|, it contains up to four
fields that can be referred to as follows:
$$\vbox{\halign{\hfil#&#\hfil&#\hfil\cr
|x|&.|int|&(an |integer|)\cr
|x|&.|sc|\qquad&(a |scaled| integer)\cr
|x|&.|gr|&(a |glue_ratio|)\cr
|x.hh.lh|, |x.hh|&.|rh|&(two halfword fields)\cr
|x.hh.b0|, |x.hh.b1|, |x.hh|&.|rh|&(two quarterword fields, one halfword
  field)\cr
|x.qqqq.b0|, |x.qqqq.b1|, |x.qqqq|&.|b2|, |x.qqqq.b3|\hskip-100pt
  &\qquad\qquad\qquad(four quarterword fields)\cr}}$$
This is somewhat cumbersome to write, and not very readable either, but
macros will be used to make the notation shorter and more transparent.
The \PASCAL\ code below gives a formal definition of |memory_word| and
its subsidiary types, using packed variant records. \TeX\ makes no
assumptions about the relative positions of the fields within a word.

We are assuming 32-bit integers, a halfword must contain at least
32 bits, and a quarterword must contain at least 16 bits.
@^system dependencies@>

N.B.: Valuable memory space will be dreadfully wasted unless \TeX\ is compiled
by a \PASCAL\ that packs all of the |memory_word| variants into
the space of a single integer. This means, for example, that |glue_ratio|
words should be |short_real| instead of |real| on some computers. Some
\PASCAL\ compilers will pack an integer whose subrange is `|0..255|' into
an eight-bit field, but others insist on allocating space for an additional
sign bit; on such systems you can get 256 values into a quarterword only
if the subrange is `|-128..127|'.

The present implementation tries to accommodate as many variations as possible,
so it makes few assumptions. If integers having the subrange
`|min_quarterword..max_quarterword|' can be packed into a quarterword,
and if integers having the subrange `|min_halfword..max_halfword|'
can be packed into a halfword, everything should work satisfactorily.

It is usually most efficient to have |min_quarterword=min_halfword=0|,
so one should try to achieve this unless it causes a severe problem.
The values defined here are recommended for most 32-bit computers.

We cannot use the full range of 32 bits in a halfword, because we have
to allow negative values for potential backend tricks like web2c's
dynamic allocation, and parshapes pointers have to be able to store at
least twice the value |max_halfword| (see below). Therefore,
|max_halfword| is $2^{30}-1$

@d min_quarterword=0 {smallest allowable value in a |quarterword|}
@d max_quarterword=65535 {largest allowable value in a |quarterword|}
@d min_halfword==-@"3FFFFFFF {smallest allowable value in a |halfword|}
@d max_halfword==@"3FFFFFFF {largest allowable value in a |halfword|}

@ Here are the inequalities that the quarterword and halfword values
must satisfy (or rather, the inequalities that they mustn't satisfy):

@<Check the ``constant''...@>=
if (min_quarterword>0)or(max_quarterword<@"7FFF) then bad:=11;
if (min_halfword>0)or(max_halfword<@"3FFFFFFF) then bad:=12;
if (min_quarterword<min_halfword)or@|
  (max_quarterword>max_halfword) then bad:=13;
if font_base<min_quarterword then bad:=15;
if (save_size>max_halfword)or(max_strings>max_halfword) then bad:=17;
if buf_size>max_halfword then bad:=18;
if max_quarterword-min_quarterword<@"FFFF then bad:=19;

@ The operation of adding or subtracting |min_quarterword| occurs quite
frequently in \TeX, so it is convenient to abbreviate this operation
by using the macros |qi| and |qo| for input and output to and from
quarterword format.

The inner loop of \TeX\ will run faster with respect to compilers
that don't optimize expressions like `|x+0|' and `|x-0|', if these
macros are simplified in the obvious way when |min_quarterword=0|.
@^inner loop@>@^system dependencies@>

@d qi(#)==#+min_quarterword
  {to put an |eight_bits| item into a quarterword}
@d qo(#)==#-min_quarterword
  {to take an |eight_bits| item out of a quarterword}
@d hi(#)==#+min_halfword
  {to put a sixteen-bit item into a halfword}
@d ho(#)==#-min_halfword
  {to take a sixteen-bit item from a halfword}

@ The reader should study the following definitions closely:
@^system dependencies@>

@d sc==int {|scaled| data is equivalent to |integer|}

@<Types...@>=
@!quarterword = min_quarterword..max_quarterword; {1/4 of a word}
@!halfword=min_halfword..max_halfword; {1/2 of a word}
@!two_choices = 1..2; {used when there are two variants in a record}
@!four_choices = 1..4; {used when there are four variants in a record}
@!two_halves = packed record@;@/
  @!rh:halfword;
  case two_choices of
  1: (@!lh:halfword);
  2: (@!b0:quarterword; @!b1:quarterword);
  end;
@!four_quarters = packed record@;@/
  @!b0:quarterword;
  @!b1:quarterword;
  @!b2:quarterword;
  @!b3:quarterword;
  end;
@!memory_word = record@;@/
  case four_choices of
  1: (@!int:integer);
  2: (@!gr:glue_ratio);
  3: (@!hh:two_halves);
  4: (@!qqqq:four_quarters);
  end;
@!word_file = file of memory_word;

@ When debugging, we may want to print a |memory_word| without knowing
what type it is; so we print it in all modes.
@^dirty \PASCAL@>@^debugging@>

@p @!debug procedure print_word(@!w:memory_word);
  {prints |w| in all ways}
begin print_int(w.int); print_char(" ");@/
print_scaled(w.sc); print_char(" ");@/
print_scaled(round(unity*float(w.gr))); print_ln;@/
@^real multiplication@>
print_int(w.hh.lh); print_char("="); print_int(w.hh.b0); print_char(":");
print_int(w.hh.b1); print_char(";"); print_int(w.hh.rh); print_char(" ");@/
print_int(w.qqqq.b0); print_char(":"); print_int(w.qqqq.b1); print_char(":");
print_int(w.qqqq.b2); print_char(":"); print_int(w.qqqq.b3);
end;
gubed

@* \[9] Dynamic memory allocation.
The \TeX\ system does nearly all of its own memory allocation, so that it
can readily be transported into environments that do not have automatic
facilities for strings, garbage collection, etc., and so that it can be in
control of what error messages the user receives. The dynamic storage
requirements of \TeX\ are handled by providing two large arrays called
|fixmem| and |varmem| in which consecutive blocks of words are used as
nodes by the \TeX\ routines.

Pointer variables are indices into this array, or into another array
called |eqtb| that will be explained later. A pointer variable might
also be a special flag that lies outside the bounds of |mem|, so we
allow pointers to assume any |halfword| value. The minimum halfword
value represents a null pointer. \TeX\ does not assume that |mem[null]| exists.

@d pointer==halfword {a flag or a location in |mem| or |eqtb|}
@d null==0 {the null pointer}

@<Glob...@>=
@!temp_ptr:pointer; {a pointer variable for occasional emergency use}

@ @<Types...@>=
@!smemory_word = packed record@;@/
  @!hhrh:halfword;
  @!hhlh:halfword;
  end;


@ The |mem| array is divided into two items that are allocated separately;
they grow until finding their ``natural'' size in a particular job.
Locations in |varmem| are used for storing variable-length records
consisting of two or more words each. This region
is maintained using an algorithm similar to the one described in exercise
2.5--19 of {\sl The Art of Computer Programming}. However, no size field
appears in the allocated nodes; the program is responsible for knowing the
relevant size when a node is freed. Locations in |fixmem| are used for storing
one-word records; a conventional \.{AVAIL} stack is used for allocation
in this array.

Empirical tests show that the present implementation of \TeX\ tends to
spend about 9\pct! of its running time allocating nodes, and about 6\pct!
deallocating them after their use.

@d fix_mem_init==10000

@<Glob...@>=
@!fixmem : ^smemory_word; {the big dynamic storage area}
@!fix_mem_min : pointer; {the smallest location of one-word memory in use}
@!fix_mem_max : pointer; {the largest location of one-word memory in use}

@ In order to study the memory requirements of particular applications, it
is possible to prepare a version of \TeX\ that keeps track of current and
maximum memory usage. When code between the delimiters |@!stat| $\ldots$
|tats| is not ``commented out,'' \TeX\ will run a bit slower but it will
report these statistics when |tracing_stats| is sufficiently large.

@<Glob...@>=
@!var_used, @!dyn_used : integer; {how much memory is in use}

@ Let's consider the one-word memory region first, since it's the
simplest. The pointer variable |fix_mem_end| holds the highest-numbered location
of |mem| that has ever been used. The free locations of |mem| that
occur between |hi_mem_min| and |fix_mem_end|, inclusive, are of type
|two_halves|, and we write |info(p)| and |link(p)| for the |lh|
and |rh| fields of |mem[p]| when it is of this type. The single-word
free locations form a linked list
$$|avail|,\;\hbox{|link(avail)|},\;\hbox{|link(link(avail))|},\;\ldots$$
terminated by |null|.

@d mem(#) == fixmem[#]
@d link(#) == mem(#).hhrh {the |link| field of a memory word}
@d info(#) == mem(#).hhlh {the |info| field of a memory word}

@<Glob...@>=
@!avail : pointer; {head of the list of available one-word nodes}
@!fix_mem_end : pointer; {the last one-word node used in |mem|}

@ If memory is exhausted, it might mean that the user has forgotten
a right brace. We will define some procedures later that try to help
pinpoint the trouble.

@p @<Declare the procedure called |show_token_list|@>@/
@<Declare the procedure called |runaway|@>

@ The function |get_avail| returns a pointer to a new one-word node whose
|link| field is null. However, \TeX\ will halt if there is no more room left.
@^inner loop@>

If the available-space list is empty, i.e., if |avail=null|,
we try first to increase |fix_mem_end|. If that cannot be done, i.e., if
|fix_mem_end=fix_mem_max|, we try to reallocate array |fixmem|.
If, that doesn't work, we have to quit.

@p function get_avail : pointer; {single-word node allocation}
var p:pointer; {the new node being got}
t:integer;
begin p:=avail; {get top location in the |avail| stack}
if p<>null then avail:=link(avail) {and pop it off}
else if fix_mem_end<fix_mem_max then {or go into virgin territory}
  begin incr(fix_mem_end); p:=fix_mem_end;
  end
else  begin
  t:=(fix_mem_max/5);
  fixmem := fixmemcast(realloc(fixmem,sizeof(smemory_word)*(fix_mem_max+t+1)));
  if fixmem=NULL then
    begin runaway; {if memory is exhausted, display possible runaway text}
    overflow("token memory size",fix_mem_max);
      {quit; all one-word nodes are busy}
@:TeX capacity exceeded main memory size}{\quad main memory size@>
    end;
  memset (voidcast(fixmem+fix_mem_max+1),0,t*sizeof(smemory_word));
  fix_mem_max:=fix_mem_max+t; incr(fix_mem_end); p:=fix_mem_end;
  end;
link(p):=null; {provide an oft-desired initialization of the new node}
@!stat incr(dyn_used);@+tats@;{maintain statistics}
get_avail:=p;
end;

@ Conversely, a one-word node is recycled by calling |free_avail|.
This routine is part of \TeX's ``inner loop,'' so we want it to be fast.
@^inner loop@>

@d free_avail(#)== {single-word node liberation}
  begin link(#):=avail; avail:=#;
  @!stat decr(dyn_used);@+tats@/
  end

@ There's also a |fast_get_avail| routine, which saves the procedure-call
overhead at the expense of extra programming. This routine is used in
the places that would otherwise account for the most calls of |get_avail|.
@^inner loop@>

@d fast_get_avail(#)==@t@>@;@/
  begin #:=avail; {avoid |get_avail| if possible, to save time}
  if #=null then #:=get_avail
  else  begin avail:=link(#); link(#):=null;
    @!stat incr(dyn_used);@+tats@/
    end;
  end

@ The procedure |flush_list(p)| frees an entire linked list of
one-word nodes that starts at position |p|.
@^inner loop@>

@p procedure flush_list(@!p:pointer); {makes list of single-word nodes available}
var @!q,@!r:pointer; {list traversers}
begin if p<>null then
  begin r:=p;
  repeat q:=r; r:=link(r); @!stat decr(dyn_used);@+tats@/
  until r=null; {now |q| is the last node on the list}
  link(q):=avail; avail:=p;
  end;
end;

@ The available-space list that keeps track of the variable-size portion
of |mem| is a nonempty, doubly-linked circular list of empty nodes,
pointed to by the roving pointer |rover|.

@d vmem(#) == varmem[#]
@d vlink(#) == vmem(#).hh.rh {the |link| field of a memory word}
@d vinfo(#) == vmem(#).hh.lh {the |info| field of a memory word}
@d alink(#) == vlink(#+1) {backlink in doubly-linked list of empty nodes}

@* \[10] Data structures for boxes and their friends.
From the computer's standpoint, \TeX's chief mission is to create
horizontal and vertical lists. We shall now investigate how the elements
of these lists are represented internally as nodes in the dynamic memory.

A horizontal or vertical list is linked together by |link| fields in
the first word of each node. Individual nodes represent boxes, glue,
penalties, or special things like discretionary hyphens; because of this
variety, some nodes are longer than others, and we must distinguish different
kinds of nodes. We do this by putting a `|type|' field in the first word,
together with the link and an optional `|subtype|'.

@d type(#)    == vmem(#).hh.b0  {identifies what kind of node this is}
@d subtype(#) == vmem(#).hh.b1 {secondary identification in some cases}

@ TH: This module section is superceded.

A |@!char_node|, which represents a single character, is the most important
kind of node because it accounts for the vast majority of all boxes.
Special precautions are therefore taken to ensure that a |char_node| does
not take up much memory space. Every such node is one word long, and in fact
it is identifiable by this property, since other kinds of nodes have at least
two words, and they appear in |mem| locations less than |hi_mem_min|.
This makes it possible to omit the |type| field in a |char_node|, leaving
us room for two bytes that identify a |font| and a |character| within
that font.

Note that the format of a |char_node| allows for up to 256 different
fonts and up to 256 characters per font; but most implementations will
probably limit the total number of fonts to fewer than 75 per job,
and most fonts will stick to characters whose codes are
less than 128 (since higher codes
are more difficult to access on most keyboards).

Extensions of \TeX\ intended for oriental languages will need even more
than $256\times256$ possible characters, when we consider different sizes
@^oriental characters@>@^Chinese characters@>@^Japanese characters@>
and styles of type.  It is suggested that Chinese and Japanese fonts be
handled by representing such characters in two consecutive |char_node|
entries: The first of these has |font=font_base|, and its |link| points
to the second;
the second identifies the font and the character dimensions.
The saving feature about oriental characters is that most of them have
the same box dimensions. The |character| field of the first |char_node|
is a ``\\{charext}'' that distinguishes between graphic symbols whose
dimensions are identical for typesetting purposes. (See the \MF\ manual.)
Such an extension of \TeX\ would not be difficult; further details are
left to the reader.

In order to make sure that the |character| code fits in a quarterword,
\TeX\ adds the quantity |min_quarterword| to the actual code.

Character nodes appear only in horizontal lists, never in vertical lists.

@ Attribute lists need two extra globals to increase processing efficiency.
|max_used_attr| limits the test loop that checks for set attributes, and
|attr_list_cache| contains a pointer to an already created attribute list.  It is
set to the special value |cache_disabled| when the current value can no longer be
trusted: after an assignment to an attribute register, and after a group has
ended.

@d cache_disabled==max_halfword

@<Glob...@>=
max_used_attr:integer; { maximum assigned attribute id }
attr_list_cache:pointer;

@ @<Set init...@>=
max_used_attr:=-1; attr_list_cache:=cache_disabled;

@ Attribute lists are maintained in C, but they need access to the current
attributes in eqtb.

@p function get_attribute(i:halfword):halfword;
begin
  get_attribute := attribute(i);
end;


@ An |hlist_node| stands for a box that was made from a horizontal list.
Each |hlist_node| is seven words long, and contains the following fields
(in addition to the mandatory |type| and |link|, which we shall not
mention explicitly when discussing the other node types): The |height| and
|width| and |depth| are scaled integers denoting the dimensions of the
box.  There is also a |shift_amount| field, a scaled integer indicating
how much this box should be lowered (if it appears in a horizontal list),
or how much it should be moved to the right (if it appears in a vertical
list). There is a |list_ptr| field, which points to the beginning of the
list from which this box was fabricated; if |list_ptr| is |null|, the box
is empty. Finally, there are three fields that represent the setting of
the glue:  |glue_set(p)| is a word of type |glue_ratio| that represents
the proportionality constant for glue setting; |glue_sign(p)| is
|stretching| or |shrinking| or |normal| depending on whether or not the
glue should stretch or shrink or remain rigid; and |glue_order(p)|
specifies the order of infinity to which glue setting applies (|normal|,
|sfi|, |fil|, |fill|, or |filll|). The |subtype| field is not used.

@d width_offset=2 {position of |width| field in a box node}
@d depth_offset=3 {position of |depth| field in a box node}
@d height_offset=4 {position of |height| field in a box node}
@d width(#) == vmem(#+width_offset).sc {width of the box, in sp}
@d depth(#) == vmem(#+depth_offset).sc {depth of the box, in sp}
@d height(#) == vmem(#+height_offset).sc {height of the box, in sp}
@d shift_amount(#) == vlink(#+5) {repositioning distance, in sp}
@d box_dir(#) == vinfo(#+5) {position of |box_dir| in a box node}
@d list_offset=6 {position of |list_ptr| field in a box node}
@d list_ptr(#) == vlink(#+list_offset) {beginning of the list inside the box}
@d glue_order(#) == subtype(#+list_offset) {applicable order of infinity}
@d glue_sign(#) == type(#+list_offset) {stretching or shrinking}
@d normal=0 {the most common case when several cases are named}
@d stretching = 1 {glue setting applies to the stretch components}
@d shrinking = 2 {glue setting applies to the shrink components}
@d glue_set(#) == vmem(#+7).gr {a word of type |glue_ratio| for glue setting}

@ The |new_null_box| function returns a pointer to an |hlist_node| in
which all subfields have the values corresponding to `\.{\\hbox\{\}}'.
The |subtype| field is set to |min_quarterword|, since that's the desired
|span_count| value if this |hlist_node| is changed to an |unset_node|.

@p function new_null_box:pointer; {creates a new box node}
var p:pointer; {the new node}
begin p:=new_node(hlist_node,min_quarterword);
box_dir(p):=text_direction;
new_null_box:=p;
end;

@ A |vlist_node| is like an |hlist_node| in all respects except that it
contains a vertical list.

@ A |rule_node| stands for a solid black rectangle; it has |width|,
|depth|, and |height| fields just as in an |hlist_node|. However, if
any of these dimensions is $-2^{30}$, the actual value will be determined
by running the rule up to the boundary of the innermost enclosing box.
This is called a ``running dimension.'' The |width| is never running in
an hlist; the |height| and |depth| are never running in a~vlist.

@d null_flag==-@'10000000000 {$-2^{30}$, signifies a missing item}
@d is_running(#) == (#=null_flag) {tests for a running dimension}
@d rule_dir(#)==vlink(#+5)

@ A new rule node is delivered by the |new_rule| function. It
makes all the dimensions ``running,'' so you have to change the
ones that are not allowed to run.

@p
function new_rule:pointer;
var p:pointer; {the new node}
begin p:=new_node(rule_node,0); {the |subtype| is not used}
new_rule:=p;
end;


@ Insertions are represented by |ins_node| records, where the |subtype|
indicates the corresponding box number. For example, `\.{\\insert 250}'
leads to an |ins_node| whose |subtype| is |250+min_quarterword|.
The |height| field of an |ins_node| is slightly misnamed; it actually holds
the natural height plus depth of the vertical list being inserted.
The |depth| field holds the |split_max_depth| to be used in case this
insertion is split, and the |split_top_ptr| points to the corresponding
|split_top_skip|. The |float_cost| field holds the |floating_penalty| that
will be used if this insertion floats to a subsequent page after a
split insertion of the same class.  There is one more field, the
|ins_ptr|, which points to the beginning of the vlist for the insertion.

@d float_cost(#)==vmem(#+2).int {the |floating_penalty| to be used}
@d ins_ptr(#)==vinfo(#+5) {the vertical list to be inserted}
@d split_top_ptr(#)==vlink(#+5) {the |split_top_skip| to be used}

@ A |mark_node| has a |mark_ptr| field that points to the reference count
of a token list that contains the user's \.{\\mark} text.
In addition there is a |mark_class| field that contains the mark class.

@d mark_ptr(#)==vlink(#+2) {head of the token list for a mark}
@d mark_class(#)==vinfo(#+2) {the mark class}

@ An |adjust_node|, which occurs only in horizontal lists,
specifies material that will be moved out into the surrounding
vertical list; i.e., it is used to implement \TeX's `\.{\\vadjust}'
operation.  The |adjust_ptr| field points to the vlist containing this
material.

@d adjust_pre == subtype  {pre-adjustment?}
@d adjust_ptr(#)==vlink(#+2) {vertical list to be moved out of horizontal list}
@#{|append_list| is used to append a list to |tail|}
@d append_list(#) == begin vlink(tail) := vlink(#); append_list_end
@d append_list_end(#) == tail := #; end

@ A |glyph_node|, which occurs only in horizontal lists, specifies a
glyph in a particular font, along with its attribute list. Older
versions of \TeX\ could use token memory for characters, because the
font,char combination would fit in a single word (both values were
required to be strictly less than $2^{16}$). In \LuaTeX, room is
needed for characters that are larger than that, as well as a pointer
to a potential attribute list, and the two displacement values.

In turn, that made the node so large that it made sense to merge
ligature glyphs as well, as that requires only one extra pointer.  A
few extra classes of glyph nodes will be introduced later.  The
unification of all those types makes it easier to manipulate lists of
glyphs. The subtype differentiates various glyph kinds.

First, here is a function that returns a pointer to a glyph node for a given
glyph in a given font. If that glyph doesn't exist, |null| is returned
instead.  Nodes of this subtype are directly created only for accents
and their base (through |make_accent|), and math nucleus items (in the
conversion from |mlist| to |hlist|).


@d is_char_node(#) == ((#<>null)and(type(#)=glyph_node))
@d font(#)==vlink(#+2) {the font code in a |glyph_node|}
@d character(#)==vinfo(#+2) {the character code in a |glyph_node|}
@d lig_ptr(#)==vlink(#+3) {the list of characters for ligature replacements }
@d lang_data(#)==vinfo(#+3) {language information }
@d x_displace(#)==vinfo(#+4) { horizontal displacement }
@d y_displace(#)==vlink(#+4) { vertical displacement  }

@p function new_glyph(@!f,@!c:integer):pointer;
var p:pointer; {the new node}
begin p:=null;
if (f=0) or (char_exists(f,c)) then begin
  p:=new_glyph_node;
  set_to_glyph(p); font(p):=f;  character(p):=c;
  end;
new_glyph:=p;
end;


@ A subset of the glyphs nodes represent ligatures: characters
fabricated from the interaction of two or more actual characters.  The
characters that generated the ligature have not been forgotten, since
they are needed for diagnostic messages; the |lig_ptr| field points to
a linked list of character nodes for all original characters that have
been deleted. (This list might be empty if the characters that
generated the ligature were retained in other nodes.)

The |subtype| field of these |glyph_node|s is 1, plus 2 and/or 1 if
the original source of the ligature included implicit left and/or
right boundaries. These nodes are created by the C function |new_ligkern|.

@ A third general type of glyphs could be called a character, as it
only appears in lists that are not yet processed by the ligaturing and
kerning steps of the program.

|main_control| inserts these, and they are later converted to
|subtype_normal| by |new_ligkern|.

@p function norm_min(@!h:integer):quarterword;
begin if h<=0 then norm_min:=1@+else if h>=255 then norm_min:=255@+
else norm_min:=h;
end;
@#
function new_char(@!f,@!c:integer):pointer;
var p:pointer; {the new node}
begin p:=new_glyph_node;
set_to_character(p); font(p):=f;  character(p):=c;
lang_data(p):=make_lang_data(uc_hyph,cur_lang,left_hyphen_min,right_hyphen_min);
new_char:=p;
end;

@ Left and right ghost glyph nodes are the result of \.{\\leftghost}
and \.{\\rightghost}, respectively. They are going to be removed by
|new_ligkern|, at the end of which they are no longer needed.

@ Here are a few handy helpers used by the list output routines.

@p
function glyph_width(@!p:halfword):pointer;
var w:integer;
begin
  w := char_width(font(p),character(p)); { |+ x_displace(p);| }
  glyph_width := w;
end;
@#
function glyph_height(@!p:halfword):pointer;
var w:integer;
begin
  w := char_height(font(p),character(p)) + y_displace(p);
  if w<0 then w:=0;
  glyph_height := w;
end;
@#
function glyph_depth(@!p:halfword):pointer;
var w:integer;
begin
  w := char_depth(font(p),character(p));
  if y_displace(p)>0 then w := w - y_displace(p);
  if w<0 then w:=0;
  glyph_depth := w;
end;


@ A |disc_node|, which occurs only in horizontal lists, specifies a
``dis\-cretion\-ary'' line break. If such a break occurs at node |p|, the text
that starts at |pre_break(p)| will precede the break, the text that starts at
|post_break(p)| will follow the break, and text that appears in
|no_break(p)| nodes will be ignored. For example, an ordinary
discretionary hyphen, indicated by `\.{\\-}', yields a |disc_node| with
|pre_break| pointing to a |char_node| containing a hyphen, |post_break=null|,
and |no_break=null|.

{TODO: Knuth said: All three of the discretionary texts must be lists
that consist entirely of character, kern, box and rule nodes.}

If |subtype(p)=automatic_disc|, the |ex_hyphen_penalty| will be charged for this
break.  Otherwise the |hyphen_penalty| will be charged.  The texts will
actually be substituted into the list by the line-breaking algorithm if it
decides to make the break, and the discretionary node will disappear at
that time; thus, the output routine sees only discretionaries that were
not chosen.

@d automatic_disc=2
@d syllable_disc=3
@d disc_type==subtype {the kind of discretionary}
@d pre_break(#)==vinfo(#+2) {text that precedes a discretionary break}
@d post_break(#)==vlink(#+2) {text that follows a discretionary break}
@d no_break(#)==vlink(#+3) {text this discretionary break replaces}
@d pre_break_head(#)==(#+4)
@d post_break_head(#)==(#+6)
@d no_break_head(#)==(#+8)
@d tlink(#)==vinfo(#+1)

@p function new_disc:pointer; {creates an empty |disc_node|}
var p:pointer; {the new node}
begin p:=new_node(disc_node,0);
new_disc:=p;
end;

@ A |whatsit_node| is a wild card reserved for extensions to \TeX. The
|subtype| field in its first word says what `\\{whatsit}' it is, and
implicitly determines the node size (which must be 2 or more) and the
format of the remaining words. When a |whatsit_node| is encountered
in a list, special actions are invoked; knowledgeable people who are
careful not to mess up the rest of \TeX\ are able to make \TeX\ do new
things by adding code at the end of the program. For example, there
might be a `\TeX nicolor' extension to specify different colors of ink,
@^extensions to \TeX@>
and the whatsit node might contain the desired parameters.

The present implementation of \TeX\ treats the features associated with
`\.{\\write}' and `\.{\\special}' as if they were extensions, in order to
illustrate how such routines might be coded. We shall defer further
discussion of extensions until the end of this program.

@ A |math_node|, which occurs only in horizontal lists, appears before and
after mathematical formulas. The |subtype| field is |before| before the
formula and |after| after it. There is a |surround| field, which represents
the amount of surrounding space inserted by \.{\\mathsurround}.

@d surround(#)==vlink(#+2)
@d before=0 {|subtype| for math node that introduces a formula}
@d after=1 {|subtype| for math node that winds up a formula}

@p function new_math(@!w:scaled;@!s:small_number):pointer;
var p:pointer; {the new node}
begin p:=new_node(math_node,s);
surround(p):=w; new_math:=p;
end;

@ \TeX\ makes use of the fact that |hlist_node|, |vlist_node|,
|rule_node|, |ins_node|, |mark_node|, |adjust_node|,
|disc_node|, |whatsit_node|, and |math_node| are at the low end of the
type codes, by permitting a break at glue in a list if and only if the
|type| of the previous node is less than |math_node|. Furthermore, a
node is discarded after a break if its type is |math_node| or~more.

@d precedes_break(#)==(type(#)<math_node)
@d non_discardable(#)==(type(#)<math_node)

@ A |glue_node| represents glue in a list. However, it is really only
a pointer to a separate glue specification, since \TeX\ makes use of the
fact that many essentially identical nodes of glue are usually present.
If |p| points to a |glue_node|, |glue_ptr(p)| points to
another packet of words that specify the stretch and shrink components, etc.

Glue nodes also serve to represent leaders; the |subtype| is used to
distinguish between ordinary glue (which is called |normal|) and the three
kinds of leaders (which are called |a_leaders|, |c_leaders|, and |x_leaders|).
The |leader_ptr| field points to a rule node or to a box node containing the
leaders; it is set to |null| in ordinary glue nodes.

Many kinds of glue are computed from \TeX's ``skip'' parameters, and
it is helpful to know which parameter has led to a particular glue node.
Therefore the |subtype| is set to indicate the source of glue, whenever
it originated as a parameter. We will be defining symbolic names for the
parameter numbers later (e.g., |line_skip_code=0|, |baseline_skip_code=1|,
etc.); it suffices for now to say that the |subtype| of parametric glue
will be the same as the parameter number, plus~one.

In math formulas there are two more possibilities for the |subtype| in a
glue node: |mu_glue| denotes an \.{\\mskip} (where the units are scaled \.{mu}
instead of scaled \.{pt}); and |cond_math_glue| denotes the `\.{\\nonscript}'
feature that cancels the glue node immediately following if it appears
in a subscript.

@d cond_math_glue=98 {special |subtype| to suppress glue in the next node}
@d mu_glue=99 {|subtype| for math glue}
@d a_leaders=100 {|subtype| for aligned leaders}
@d c_leaders=101 {|subtype| for centered leaders}
@d x_leaders=102 {|subtype| for expanded leaders}
@d glue_ptr(#)==vinfo(#+2) {pointer to a glue specification}
@d leader_ptr(#)==vlink(#+2) {pointer to box or rule node for leaders}

@ A glue specification has a halfword reference count in its first word,
@^reference counts@>
representing |null| plus the number of glue nodes that point to it (less one).
Note that the reference count appears in the same position as
the |link| field in list nodes; this is the field that is initialized
to |null| when a node is allocated, and it is also the field that is flagged
by |empty_flag| in empty nodes.

Glue specifications also contain three |scaled| fields, for the |width|,
|stretch|, and |shrink| dimensions. Finally, there are two one-byte
fields called |stretch_order| and |shrink_order|; these contain the
orders of infinity (|normal|, |sfi|, |fil|, |fill|, or |filll|)
corresponding to the stretch and shrink values.

@d glue_ref_count(#) == vlink(#+3) {reference count of a glue specification}
@d stretch(#) == vlink(#+1) {the stretchability of this glob of glue}
@d shrink(#) == vinfo(#+1) {the shrinkability of this glob of glue}
@d stretch_order(#) == type(#+3) {order of infinity for stretching}
@d shrink_order(#) == subtype(#+3) {order of infinity for shrinking}
@d sfi=1 {first-order infinity}
@d fil=2 {second-order infinity}
@d fill=3 {third-order infinity}
@d filll=4 {fourth-order infinity}

@<Types...@>=
@!glue_ord=normal..filll; {infinity to the 0, 1, 2, 3, or 4 power}

@ Here is a function that returns a pointer to a copy of a glue spec.
The reference count in the copy is |null|, because there is assumed
to be exactly one reference to the new specification.

@p function new_spec(@!p:pointer):pointer; {duplicates a glue specification}
var q:pointer; {the new spec}
begin q:=copy_node(p);
glue_ref_count(q):=null;
new_spec:=q;
end;

@ And here's a function that creates a glue node for a given parameter
identified by its code number; for example,
|new_param_glue(line_skip_code)| returns a pointer to a glue node for the
current \.{\\lineskip}.

@p function new_param_glue(@!n:small_number):pointer;
var p:pointer; {the new node}
@!q:pointer; {the glue specification}
begin p:=new_node(glue_node,n+1);
q:=@<Current |mem| equivalent of glue parameter number |n|@>@t@>;
glue_ptr(p):=q; incr(glue_ref_count(q));
new_param_glue:=p;
end;

@ Glue nodes that are more or less anonymous are created by |new_glue|,
whose argument points to a glue specification.

@p function new_glue(@!q:pointer):pointer;
var p:pointer; {the new node}
begin p:=new_node(glue_node,normal);
glue_ptr(p):=q; incr(glue_ref_count(q));
new_glue:=p;
end;

@ Still another subroutine is needed: This one is sort of a combination
of |new_param_glue| and |new_glue|. It creates a glue node for one of
the current glue parameters, but it makes a fresh copy of the glue
specification, since that specification will probably be subject to change,
while the parameter will stay put. The global variable |temp_ptr| is
set to the address of the new spec.

@p function new_skip_param(@!n:small_number):pointer;
var p:pointer; {the new node}
begin temp_ptr:=new_spec(@<Current |mem| equivalent of glue parameter...@>);
p:=new_glue(temp_ptr); glue_ref_count(temp_ptr):=null; subtype(p):=n+1;
new_skip_param:=p;
end;

@ A |kern_node| has a |width| field to specify a (normally negative)
amount of spacing. This spacing correction appears in horizontal lists
between letters like A and V when the font designer said that it looks
better to move them closer together or further apart. A kern node can
also appear in a vertical list, when its `|width|' denotes additional
spacing in the vertical direction. The |subtype| is either |normal| (for
kerns inserted from font information or math mode calculations) or |explicit|
(for kerns inserted from \.{\\kern} and \.{\\/} commands) or |acc_kern|
(for kerns inserted from non-math accents) or |mu_glue| (for kerns
inserted from \.{\\mkern} specifications in math formulas).

@d explicit=1 {|subtype| of kern nodes from \.{\\kern} and \.{\\/}}
@d acc_kern=2 {|subtype| of kern nodes from accents}

@# {memory structure for marginal kerns}
@d margin_char(#) == vlink(#+3)

@# {|subtype| of marginal kerns}
@d left_side == 0
@d right_side == 1

@# {base for lp/rp/ef codes starts from 2:
    0 for |hyphen_char|,
    1 for |skew_char|}
@d lp_code_base == 2
@d rp_code_base == 3
@d ef_code_base == 4
@d tag_code == 5

@d auto_kern == explicit
@d no_lig_code == 6

@ The |new_kern| function creates a kern node having a given width.

@p function new_kern(@!w:scaled):pointer;
var p:pointer; {the new node}
begin p:=new_node(kern_node,normal);
width(p):=w;
new_kern:=p;
end;

@ A |penalty_node| specifies the penalty associated with line or page
breaking, in its |penalty| field. This field is a fullword integer, but
the full range of integer values is not used: Any penalty |>=10000| is
treated as infinity, and no break will be allowed for such high values.
Similarly, any penalty |<=-10000| is treated as negative infinity, and a
break will be forced.

@d inf_penalty=inf_bad {``infinite'' penalty value}
@d eject_penalty=-inf_penalty {``negatively infinite'' penalty value}
@d penalty(#) == vlink(#+2) {the added cost of breaking a list here}

@ Anyone who has been reading the last few sections of the program will
be able to guess what comes next.

@p function new_penalty(@!m:integer):pointer;
var p:pointer; {the new node}
begin p:=new_node(penalty_node,0); {the |subtype| is not used}
penalty(p):=m; new_penalty:=p;
end;

@ You might think that we have introduced enough node types by now. Well,
almost, but there is one more: An |unset_node| has nearly the same format
as an |hlist_node| or |vlist_node|; it is used for entries in \.{\\halign}
or \.{\\valign} that are not yet in their final form, since the box
dimensions are their ``natural'' sizes before any glue adjustment has been
made. The |glue_set| word is not present; instead, we have a |glue_stretch|
field, which contains the total stretch of order |glue_order| that is
present in the hlist or vlist being boxed.
Similarly, the |shift_amount| field is replaced by a |glue_shrink| field,
containing the total shrink of order |glue_sign| that is present.
The |subtype| field is called |span_count|; an unset box typically
contains the data for |qo(span_count)+1| columns.
Unset nodes will be changed to box nodes when alignment is completed.

@d glue_stretch(#)==vmem(#+7).sc {total stretch in an unset node}
@d glue_shrink==shift_amount {total shrink in an unset node}
@d span_count==subtype {indicates the number of spanned columns}

@ In fact, there are still more types coming. When we get to math formula
processing we will see that a |style_node| has |type=14|; and a number
of larger type codes will also be defined, for use in math mode only.

@ Warning: If any changes are made to these data structure layouts, such as
changing any of the node sizes or even reordering the words of nodes,
the |copy_node_list| procedure and the memory initialization code
below may have to be changed. Such potentially dangerous parts of the
program are listed in the index under `data structure assumptions'.
@!@^data structure assumptions@>
However, other references to the nodes are made symbolically in terms of
the \.{WEB} macro definitions above, so that format changes will leave
\TeX's other algorithms intact.
@^system dependencies@>

@* \[11] Memory layout.

Some areas of |mem| are dedicated to fixed usage, since static
allocation is more efficient than dynamic allocation when we can get
away with it. For example, |zero_glue| used for glue that is `\.{0pt
plus 0pt minus 0pt}'.  A few C macro definitions accomplish the static
allocation of node memory locations by giving symbolic names to fixed
positions. The list of imported constant identifiers is: |zero_glue|,
|sfi_glue|, |fil_glue|, |fill_glue|, |ss_glue|, |fil_neg_glue| (all
glue specs), |page_ins_head| (list of insertion data for current
page), |contrib_head| (list of insertion data for current page),
|page_head| (list for current page), |temp_head| and |hold_head|
(temporary lists), |adjust_head| (head of adjustment list returned by
|hpack|), |pre_adjust_head| (head of pre-adjustment list returned by
|hpack|), |align_head| (head of alignment preamble), and
|end_span| (tail of spanned-width lists).


@<Glob...@>=
garbage:pointer;         {head of a junk list, write only}
temp_token_head:pointer; {head of a temporary list of some kind}
hold_token_head:pointer; {head of a temporary list of another kind}
omit_template:pointer;   {a constant token list}
null_list:pointer;       {permanently empty list}
backup_head:pointer;     {head of token list built by |scan_keyword|}

@ The following code gets |mem| off to a good start, when \TeX\ is
initializing itself the slow~way.

@<Local variables for init...@>=
@!k:integer; {index into |mem|, |eqtb|, etc.}

@ @<Initialize table entries...@>=
procedure init_link_heads;forward;
init_node_mem(500);
avail:=null; fix_mem_end:=0;
init_list_heads;
@<Initialize the special list heads and constant nodes@>;
initialize_active;
dyn_used:=0; {initialize statistics}

@ @p procedure init_list_heads; {initialize token list heads}
var p:halfword;
begin
p:=get_avail; temp_token_head:=p; info(temp_token_head):=0;
p:=get_avail; hold_token_head:=p; info(hold_token_head):=0;
p:=get_avail; omit_template:=p;   info(omit_template):=0;
p:=get_avail; null_list:=p;       info(null_list):=0;
p:=get_avail; backup_head:=p;     info(backup_head):=0;
p:=get_avail; garbage:=p;         info(garbage):=0;
end;

@ @p
@<Declare procedures that need to be declared forward for \pdfTeX@>

@* \[12] Displaying boxes.
We can reinforce our knowledge of the data structures just introduced
by considering two procedures that display a list in symbolic form.
The first of these, called |short_display|, is used in ``overfull box''
messages to give the top-level description of a list. The other one,
called |show_node_list|, prints a detailed description of exactly what
is in the data structure.

The philosophy of |short_display| is to ignore the fine points about exactly
what is inside boxes, except that ligatures and discretionary breaks are
expanded. As a result, |short_display| is a recursive procedure, but the
recursion is never more than one level deep.
@^recursion@>

A global variable |font_in_short_display| keeps track of the font code that
is assumed to be present when |short_display| begins; deviations from this
font will be printed.

@<Glob...@>=
@!font_in_short_display:integer; {an internal font number}

@ Boxes, rules, inserts, whatsits, marks, and things in general that are
sort of ``complicated'' are indicated only by printing `\.{[]}'.

@p
procedure print_font_identifier(f: internal_font_number);
var fonttext:str_number;
begin
    if pdf_font_blink(f) = null_font then
        fonttext := font_id_text(f)
    else
        fonttext := font_id_text(pdf_font_blink(f));
    if fonttext>0 then
        print_esc(fonttext)
    else begin
        print_esc("FONT");
        if pdf_font_blink(f) = null_font then
            print_int(f)
        else
            print_int(pdf_font_blink(f));
        end;
    if pdf_tracing_fonts > 0 then begin
        print(" (");
        print_font_name(f);
        if font_size(f) <> font_dsize(f) then begin
            print("@@");
            print_scaled(font_size(f));
            print("pt");
        end;
        print(")");
    end else
        if pdf_font_expand_ratio(f) <> 0 then begin
            print(" (");
            if pdf_font_expand_ratio(f) > 0 then
                print("+");
            print_int(pdf_font_expand_ratio(f));
            print(")");
        end;
end;

procedure short_display(@!p:integer); {prints highlights of list |p|}
begin while p<>null do
  begin if is_char_node(p) then
      begin if lig_ptr(p)<>null then
           short_display(lig_ptr(p))
        else begin
          if font(p)<>font_in_short_display then
          begin if not is_valid_font(font(p)) then
            print_char("*")
@.*\relax@>
          else print_font_identifier(font(p));
          print_char(" "); font_in_short_display:=font(p);
          end;
        print(qo(character(p)));
      end;
    end
  else @<Print a short indication of the contents of node |p|@>;
  p:=vlink(p);
  end;
end;

@ @<Print a short indication of the contents of node |p|@>=
print_short_node_contents(p)

@ The |show_node_list| routine requires some auxiliary subroutines: one to
print a font-and-character combination, one to print a token list without
its reference count, and one to print a rule dimension.

@p procedure print_font_and_char(@!p:integer); {prints |char_node| data}
begin if not is_valid_font(font(p)) then print_char("*")
@.*\relax@>
  else print_font_identifier(font(p));
  print_char(" "); print(character(p));
end;
@#
procedure print_mark(@!p:integer); {prints token list data in braces}
begin print_char("{");
if (p<fix_mem_min)or(p>fix_mem_end) then print_esc("CLOBBERED.")
else show_token_list(link(p),null,max_print_line-10);
print_char("}");
end;
@#
procedure print_rule_dimen(@!d:scaled); {prints dimension in rule node}
begin if is_running(d) then print_char("*") else print_scaled(d);
@.*\relax@>
end;
@#
procedure print_dir(d:integer);
begin
print(dir_names[dir_primary[d]]);
print(dir_names[dir_secondary[d]]);
print(dir_names[dir_tertiary[d]]);
end;


@ Then there is a subroutine that prints glue stretch and shrink, possibly
followed by the name of finite units:

@p procedure print_glue(@!d:scaled;@!order:integer;@!s:str_number);
  {prints a glue component}
begin print_scaled(d);
if (order<normal)or(order>filll) then print("foul")
else if order>normal then
  begin print("fi");
  while order>sfi do
    begin print_char("l"); decr(order);
    end;
  end
else if s<>0 then print(s);
end;

@ The next subroutine prints a whole glue specification.

@p procedure print_spec(@!p:integer;@!s:str_number);
  {prints a glue specification}
begin if p<0 then print_char("*")
@.*\relax@>
else  begin print_scaled(width(p));
  if s<>0 then print(s);
  if stretch(p)<>0 then
    begin print(" plus "); print_glue(stretch(p),stretch_order(p),s);
    end;
  if shrink(p)<>0 then
    begin print(" minus "); print_glue(shrink(p),shrink_order(p),s);
    end;
  end;
end;

@ We also need to declare some procedures that appear later in this
documentation.

@p @<Declare the procedure called |print_skip_param|@>

@ Since boxes can be inside of boxes, |show_node_list| is inherently recursive,
@^recursion@>
up to a given maximum number of levels.  The history of nesting is indicated
by the current string, which will be printed at the beginning of each line;
the length of this string, namely |cur_length|, is the depth of nesting.

@ A global variable called |depth_threshold| is used to record the maximum
depth of nesting for which |show_node_list| will show information.  If we
have |depth_threshold=0|, for example, only the top level information will
be given and no sublists will be traversed. Another global variable, called
|breadth_max|, tells the maximum number of items to show at each level;
|breadth_max| had better be positive, or you won't see anything.

@<Glob...@>=
@!depth_threshold : integer; {maximum nesting depth in box displays}
@!breadth_max : integer; {maximum number of items shown at the same list level}


@ The recursive machinery is started by calling |show_box|.
@^recursion@>

@p procedure show_box(@!p:pointer);
begin @<Assign the values |depth_threshold:=show_box_depth| and
  |breadth_max:=show_box_breadth|@>;
if breadth_max<=0 then breadth_max:=5;
if pool_ptr+depth_threshold>=pool_size then
  depth_threshold:=pool_size-pool_ptr-1;
  {now there's enough room for prefix string}
show_node_list(p); {the show starts at |p|}
print_ln;
end;

@* \[13] Destroying boxes.
When we are done with a node list, we are obliged to return it to free
storage, including all of its sublists. The recursive procedure
|flush_node_list| does this for us.

@ First, however, we shall consider two non-recursive procedures that do
simpler tasks. The first of these, |delete_token_ref|, is called when
a pointer to a token list's reference count is being removed. This means
that the token list should disappear if the reference count was |null|,
otherwise the count should be decreased by one.
@^reference counts@>

@d token_ref_count(#) == info(#) {reference count preceding a token list}

@p procedure delete_token_ref(@!p:pointer); {|p| points to the reference count
  of a token list that is losing one reference}
begin pdfassert(token_ref_count(p)>=0);
if token_ref_count(p)=0 then flush_list(p)
else decr(token_ref_count(p));
end;

@ Similarly, |delete_glue_ref| is called when a pointer to a glue
specification is being withdrawn.
@^reference counts@>
@d fast_delete_glue_ref(#)==@t@>@;@/
  begin if glue_ref_count(#)=null then begin
    flush_node(#);
    end
  else decr(glue_ref_count(#));
  end

@p procedure delete_glue_ref(@!p:pointer); {|p| points to a glue specification}
begin
  pdfassert(type(p)=glue_spec_node);
  fast_delete_glue_ref(p);
end;

@ Now we are ready to delete any node list, recursively.
In practice, the nodes deleted are usually charnodes (about 2/3 of the time),
and they are glue nodes in about half of the remaining cases.
@^recursion@>


@* \[14] Copying boxes.
Another recursive operation that acts on boxes is sometimes needed: The
procedure |copy_node_list| returns a pointer to another node list that has
the same structure and meaning as the original. Note that since glue
specifications and token lists have reference counts, we need not make
copies of them. Reference counts can never get too large to fit in a
halfword, since each pointer to a node is in a different memory address,
and the total number of memory addresses fits in a halfword.
@^recursion@>
@^reference counts@>

(Well, there actually are also references from outside |mem|; if the
|save_stack| is made arbitrarily large, it would theoretically be possible
to break \TeX\ by overflowing a reference count. But who would want to do that?)

@d add_token_ref(#)==incr(token_ref_count(#)) {new reference to a token list}
@d add_glue_ref(#)==incr(glue_ref_count(#)) {new reference to a glue spec}

@p function tail_of_list (@!p:pointer):pointer;
var q:pointer;
begin
  q:=p;
  while vlink(q)<>null do q:=vlink(q);
  tail_of_list:=q;
end;

@* \[15] The command codes.
Before we can go any further, we need to define symbolic names for the internal
code numbers that represent the various commands obeyed by \TeX. These codes
are somewhat arbitrary, but not completely so. For example, the command
codes for character types are fixed by the language, since a user says,
e.g., `\.{\\catcode \`\\\${} = 3}' to make \.{\char'44} a math delimiter,
and the command code |math_shift| is equal to~3. Some other codes have
been made adjacent so that |case| statements in the program need not consider
cases that are widely spaced, or so that |case| statements can be replaced
by |if| statements.

At any rate, here is the list, for future reference. First come the
``catcode'' commands, several of which share their numeric codes with
ordinary commands when the catcode cannot emerge from \TeX's scanning routine.

@d escape=0 {escape delimiter (called \.\\ in {\sl The \TeX book\/})}
@:TeXbook}{\sl The \TeX book@>
@d relax=0 {do nothing ( \.{\\relax} )}
@d left_brace=1 {beginning of a group ( \.\{ )}
@d right_brace=2 {ending of a group ( \.\} )}
@d math_shift=3 {mathematics shift character ( \.\$ )}
@d tab_mark=4 {alignment delimiter ( \.\&, \.{\\span} )}
@d car_ret=5 {end of line ( |carriage_return|, \.{\\cr}, \.{\\crcr} )}
@d out_param=5 {output a macro parameter}
@d mac_param=6 {macro parameter symbol ( \.\# )}
@d sup_mark=7 {superscript ( \.{\char'136} )}
@d sub_mark=8 {subscript ( \.{\char'137} )}
@d ignore=9 {characters to ignore ( \.{\^\^@@} )}
@d endv=9 {end of \<v_j> list in alignment template}
@d spacer=10 {characters equivalent to blank space ( \.{\ } )}
@d letter=11 {characters regarded as letters ( \.{A..Z}, \.{a..z} )}
@d other_char=12 {none of the special character types}
@d active_char=13 {characters that invoke macros ( \.{\char`\~} )}
@d par_end=13 {end of paragraph ( \.{\\par} )}
@d match=13 {match a macro parameter}
@d comment=14 {characters that introduce comments ( \.\% )}
@d end_match=14 {end of parameters to macro}
@d stop=14 {end of job ( \.{\\end}, \.{\\dump} )}
@d invalid_char=15 {characters that shouldn't appear ( \.{\^\^?} )}
@d delim_num=15 {specify delimiter numerically ( \.{\\delimiter} )}
@d max_char_code=15 {largest catcode for individual characters}

@ Next are the ordinary run-of-the-mill command codes.  Codes that are
|min_internal| or more represent internal quantities that might be
expanded by `\.{\\the}'.

@d char_num=16 {character specified numerically ( \.{\\char} )}
@d math_char_num=17 {explicit math code ( \.{\\mathchar} )}
@d mark=18 {mark definition ( \.{\\mark} )}
@d xray=19 {peek inside of \TeX\ ( \.{\\show}, \.{\\showbox}, etc.~)}
@d make_box=20 {make a box ( \.{\\box}, \.{\\copy}, \.{\\hbox}, etc.~)}
@d hmove=21 {horizontal motion ( \.{\\moveleft}, \.{\\moveright} )}
@d vmove=22 {vertical motion ( \.{\\raise}, \.{\\lower} )}
@d un_hbox=23 {unglue a box ( \.{\\unhbox}, \.{\\unhcopy} )}
@d un_vbox=24 {unglue a box ( \.{\\unvbox}, \.{\\unvcopy} )}
  {( or \.{\\pagediscards}, \.{\\splitdiscards} )}
@d remove_item=25 {nullify last item ( \.{\\unpenalty},
  \.{\\unkern}, \.{\\unskip} )}
@d hskip=26 {horizontal glue ( \.{\\hskip}, \.{\\hfil}, etc.~)}
@d vskip=27 {vertical glue ( \.{\\vskip}, \.{\\vfil}, etc.~)}
@d mskip=28 {math glue ( \.{\\mskip} )}
@d kern=29 {fixed space ( \.{\\kern})}
@d mkern=30 {math kern ( \.{\\mkern} )}
@d leader_ship=31 {use a box ( \.{\\shipout}, \.{\\leaders}, etc.~)}
@d halign=32 {horizontal table alignment ( \.{\\halign} )}
@d valign=33 {vertical table alignment ( \.{\\valign} )}
@d no_align=34 {temporary escape from alignment ( \.{\\noalign} )}
@d vrule=35 {vertical rule ( \.{\\vrule} )}
@d hrule=36 {horizontal rule ( \.{\\hrule} )}
@d insert=37 {vlist inserted in box ( \.{\\insert} )}
@d vadjust=38 {vlist inserted in enclosing paragraph ( \.{\\vadjust} )}
@d ignore_spaces=39 {gobble |spacer| tokens ( \.{\\ignorespaces} )}
@d after_assignment=40 {save till assignment is done ( \.{\\afterassignment} )}
@d after_group=41 {save till group is done ( \.{\\aftergroup} )}
@d break_penalty=42 {additional badness ( \.{\\penalty} )}
@d start_par=43 {begin paragraph ( \.{\\indent}, \.{\\noindent} )}
@d ital_corr=44 {italic correction ( \.{\\/} )}
@d accent=45 {attach accent in text ( \.{\\accent} )}
@d math_accent=46 {attach accent in math ( \.{\\mathaccent} )}
@d discretionary=47 {discretionary texts ( \.{\\-}, \.{\\discretionary} )}
@d eq_no=48 {equation number ( \.{\\eqno}, \.{\\leqno} )}
@d left_right=49 {variable delimiter ( \.{\\left}, \.{\\right} )}
  {( or \.{\\middle} )}
@d math_comp=50 {component of formula ( \.{\\mathbin}, etc.~)}
@d limit_switch=51 {diddle limit conventions ( \.{\\displaylimits}, etc.~)}
@d above=52 {generalized fraction ( \.{\\above}, \.{\\atop}, etc.~)}
@d math_style=53 {style specification ( \.{\\displaystyle}, etc.~)}
@d math_choice=54 {choice specification ( \.{\\mathchoice}, \.{\\Ustack} )}
@d non_script=55 {conditional math glue ( \.{\\nonscript} )}
@d vcenter=56 {vertically center a vbox ( \.{\\vcenter} )}
@d case_shift=57 {force specific case ( \.{\\lowercase}, \.{\\uppercase}~)}
@d message=58 {send to user ( \.{\\message}, \.{\\errmessage} )}
@d extension=59 {extensions to \TeX\ ( \.{\\write}, \.{\\special}, etc.~)}
@d in_stream=60 {files for reading ( \.{\\openin}, \.{\\closein} )}
@d begin_group=61 {begin local grouping ( \.{\\begingroup} )}
@d end_group=62 {end local grouping ( \.{\\endgroup} )}
@d omit=63 {omit alignment template ( \.{\\omit} )}
@d ex_space=64 {explicit space ( \.{\\\ } )}
@d no_boundary=65 {suppress boundary ligatures ( \.{\\noboundary} )}
@d radical=66 {square root and similar signs ( \.{\\radical} )}
@d super_sub_script=67 {explicit super ( \.{\\Usuperscript} ) or subscript ( \.{\\Usubscript} )}
@d math_shift_cs=68 {explicit math switch ( \.{\\Ustartmath}, etc.~)}
@d end_cs_name=69 {end control sequence ( \.{\\endcsname} )}
@d char_ghost=end_cs_name+1
   {\.{\\ghostleft}, \.{\\ghostright} character for kerning}
@d assign_local_box=char_ghost+1
   {box for guillemets \.{\\localleftbox} or \.{\\localrightbox}}
@d min_internal=assign_local_box+1 {the smallest code that can follow \.{\\the}}
@d char_given=min_internal {character code defined by \.{\\chardef}}
@d math_given=char_given+1 {math code defined by \.{\\mathchardef}}
@d omath_given=math_given+1 {math code defined by \.{\\omathchardef}}
@d xmath_given=omath_given+1 {math code defined by \.{\\Umathchardef}}
@d last_item=xmath_given+1 {most recent item ( \.{\\lastpenalty},
  \.{\\lastkern}, \.{\\lastskip} )}
@d max_non_prefixed_command=last_item
   {largest command code that can't be \.{\\global}}

@ The next codes are special; they all relate to mode-independent
assignment of values to \TeX's internal registers or tables.
Codes that are |max_internal| or less represent internal quantities
that might be expanded by `\.{\\the}'.

There is no matching primitive to go with |assign_attr|, but even if
there was no \.{\\attributedef}, a reserved number would still be
needed because there is an implied correspondence between the
|assign_xxx| commands and |xxx_val| expression values. That would
break down otherwise.

@d toks_register=max_non_prefixed_command+1
   {token list register ( \.{\\toks} )}
@d assign_toks=toks_register+1
   {special token list ( \.{\\output}, \.{\\everypar}, etc.~)}
@d assign_int=assign_toks+1
   {user-defined integer ( \.{\\tolerance}, \.{\\day}, etc.~)}
@d assign_attr=assign_int+1 { user-defined attributes }
@d assign_dimen=assign_attr+1
   {user-defined length ( \.{\\hsize}, etc.~)}
@d assign_glue=assign_dimen+1
   {user-defined glue ( \.{\\baselineskip}, etc.~)}
@d assign_mu_glue=assign_glue+1
   {user-defined muglue ( \.{\\thinmuskip}, etc.~)}
@d assign_font_dimen=assign_mu_glue+1
   {user-defined font dimension ( \.{\\fontdimen} )}
@d assign_font_int=assign_font_dimen+1
   {user-defined font integer ( \.{\\hyphenchar}, \.{\\skewchar} )}
@d set_aux=assign_font_int+1
   {specify state info ( \.{\\spacefactor}, \.{\\prevdepth} )}
@d set_prev_graf=set_aux+1
   {specify state info ( \.{\\prevgraf} )}
@d set_page_dimen=set_prev_graf+1
   {specify state info ( \.{\\pagegoal}, etc.~)}
@d set_page_int=set_page_dimen+1
   {specify state info ( \.{\\deadcycles},
  \.{\\insertpenalties} )}
@d set_box_dimen=set_page_int+1
   {change dimension of box ( \.{\\wd}, \.{\\ht}, \.{\\dp} )}
@d set_tex_shape=set_box_dimen+1
   {specify fancy paragraph shape ( \.{\\parshape} )}
@d set_etex_shape=set_tex_shape+1
   {specify etex specials ( \.{\\interlinepenalties}, etc.~)}
@d def_char_code=set_etex_shape+1
   {define a character code ( \.{\\catcode}, etc.~)}
@d def_del_code=def_char_code+1
   {define a delimiter code ( \.{\\delcode})}
@d extdef_math_code=def_del_code+1
   {define an extended character code ( \.{\\omathcode}, etc.~)}
@d extdef_del_code=extdef_math_code+1
   {define an extended delimiter code ( \.{\\odelcode}, etc.~)}
@d def_family=extdef_del_code+1
   {declare math fonts ( \.{\\textfont}, etc.~)}
@d set_math_param=def_family+1
   {declare math parameters ( \.{\\Umathquad}, etc.~)}
@d set_font=set_math_param+1
   {set current font ( font identifiers )}
@d def_font=set_font+1
   {define a font file ( \.{\\font} )}
@d register=def_font+1
   {internal register ( \.{\\count}, \.{\\dimen}, etc.~)}
@d assign_box_dir=register+1 {(\.{\\boxdir})}
@d assign_dir=register+2 {(\.{\\pagedir}, \.{\\bodydir}, \.{\\pardir}, \.{\\textdir}), \.{\\mathdir}}
@d max_internal=assign_dir
   {the largest code that can follow \.{\\the}}
@d advance=max_internal+1
   {advance a register or parameter ( \.{\\advance} )}
@d multiply=advance+1
   {multiply a register or parameter ( \.{\\multiply} )}
@d divide=multiply+1
   {divide a register or parameter ( \.{\\divide} )}
@d prefix=divide+1
   {qualify a definition ( \.{\\global}, \.{\\long}, \.{\\outer} )}
@d let=prefix+1
   {assign a command code ( \.{\\let}, \.{\\futurelet} )}
@d shorthand_def=let+1
   {code definition ( \.{\\chardef}, \.{\\countdef}, etc.~)}
@d read_to_cs=shorthand_def+1
   {read into a control sequence ( \.{\\read} )}
@d def=read_to_cs+1
   {macro definition ( \.{\\def}, \.{\\gdef}, \.{\\xdef}, \.{\\edef} )}
@d set_box=def+1
   {set a box ( \.{\\setbox} )}
@d hyph_data=set_box+1
   {hyphenation data ( \.{\\hyphenation}, \.{\\patterns} )}
@d set_interaction=hyph_data+1
   {define level of interaction ( \.{\\batchmode}, etc.~)}
@d letterspace_font=set_interaction+1
   {letterspace a font ( \.{\\letterspacefont} )}
@d pdf_copy_font=letterspace_font+1
   {create a new font instance ( \.{\\pdfcopyfont} )}
@d set_ocp=pdf_copy_font+1
   {Place a translation process in the stream}
@d def_ocp=set_ocp+1
   {Define and load a translation process}
@d set_ocp_list=def_ocp+1
   {Place a list of OCPs in the stream}
@d def_ocp_list=set_ocp_list+1
   {Define a list of OCPs}
@d clear_ocp_lists=def_ocp_list+1
   {Remove all active OCP lists}
@d push_ocp_list=clear_ocp_lists+1
   {Add to the sequence of active OCP lists}
@d pop_ocp_list=push_ocp_list+1
   {Remove from the sequence of active OCP lists}
@d ocp_list_op=pop_ocp_list+1
   {Operations for building a list of OCPs}
@d ocp_trace_level=ocp_list_op+1
   {Tracing of active OCPs, either 0 or 1}
@d max_command=ocp_trace_level
  {the largest command code seen at |big_switch|}

@ The remaining command codes are extra special, since they cannot get through
\TeX's scanner to the main control routine. They have been given values higher
than |max_command| so that their special nature is easily discernible.
The ``expandable'' commands come first.

@d undefined_cs=max_command+1 {initial state of most |eq_type| fields}
@d expand_after=max_command+2 {special expansion ( \.{\\expandafter} )}
@d no_expand=max_command+3 {special nonexpansion ( \.{\\noexpand} )}
@d input=max_command+4 {input a source file ( \.{\\input}, \.{\\endinput} )}
  {( or \.{\\scantokens} or \.{\\scantextokens} )}
@d if_test=max_command+5 {conditional text ( \.{\\if}, \.{\\ifcase}, etc.~)}
@d fi_or_else=max_command+6 {delimiters for conditionals ( \.{\\else}, etc.~)}
@d cs_name=max_command+7 {make a control sequence from tokens ( \.{\\csname} )}
@d convert=max_command+8 {convert to text ( \.{\\number}, \.{\\string}, etc.~)}
@d the=max_command+9 {expand an internal quantity ( \.{\\the} )}
  {( or \.{\\unexpanded}, \.{\\detokenize} )}
@d top_bot_mark=max_command+10 {inserted mark ( \.{\\topmark}, etc.~)}
@d call=max_command+11 {non-long, non-outer control sequence}
@d long_call=max_command+12 {long, non-outer control sequence}
@d outer_call=max_command+13 {non-long, outer control sequence}
@d long_outer_call=max_command+14 {long, outer control sequence}
@d end_template=max_command+15 {end of an alignment template}
@d dont_expand=max_command+16 {the following token was marked by \.{\\noexpand}}
@d glue_ref=max_command+17 {the equivalent points to a glue specification}
@d shape_ref=max_command+18 {the equivalent points to a parshape specification}
@d box_ref=max_command+19 {the equivalent points to a box node, or is |null|}
@d data=max_command+20 {the equivalent is simply a halfword number}

@* \[16] The semantic nest.
\TeX\ is typically in the midst of building many lists at once. For example,
when a math formula is being processed, \TeX\ is in math mode and
working on an mlist; this formula has temporarily interrupted \TeX\ from
being in horizontal mode and building the hlist of a paragraph; and this
paragraph has temporarily interrupted \TeX\ from being in vertical mode
and building the vlist for the next page of a document. Similarly, when a
\.{\\vbox} occurs inside of an \.{\\hbox}, \TeX\ is temporarily
interrupted from working in restricted horizontal mode, and it enters
internal vertical mode.  The ``semantic nest'' is a stack that
keeps track of what lists and modes are currently suspended.

At each level of processing we are in one of six modes:

\yskip\hang|vmode| stands for vertical mode (the page builder);

\hang|hmode| stands for horizontal mode (the paragraph builder);

\hang|mmode| stands for displayed formula mode;

\hang|-vmode| stands for internal vertical mode (e.g., in a \.{\\vbox});

\hang|-hmode| stands for restricted horizontal mode (e.g., in an \.{\\hbox});

\hang|-mmode| stands for math formula mode (not displayed).

\yskip\noindent The mode is temporarily set to zero while processing \.{\\write}
texts in the |ship_out| routine.

Numeric values are assigned to |vmode|, |hmode|, and |mmode| so that
\TeX's ``big semantic switch'' can select the appropriate thing to
do by computing the value |abs(mode)+cur_cmd|, where |mode| is the current
mode and |cur_cmd| is the current command code.

@d vmode=1 {vertical mode}
@d hmode=vmode+max_command+1 {horizontal mode}
@d mmode=hmode+max_command+1 {math mode}

@p procedure print_mode(@!m:integer); {prints the mode represented by |m|}
begin if m>0 then
  case m div (max_command+1) of
  0:print("vertical");
  1:print("horizontal");
  2:print("display math");
  end
else if m=0 then print("no")
else  case (-m) div (max_command+1) of
  0:print("internal vertical");
  1:print("restricted horizontal");
  2:print("math");
  end;
print(" mode");
end;
function get_mode_id:integer; {returns the mode represented by |m|}
var m:integer ;
begin
  m := mode;
  if m>0 then
  case m div (max_command+1) of
  0:get_mode_id := "v";
  1:get_mode_id := "h";
  2:get_mode_id := "m";
  othercases get_mode_id := "";
  end
else if m=0 then get_mode_id := "n"
else  case (-m) div (max_command+1) of
  0:get_mode_id := "V";
  1:get_mode_id := "H";
  2:get_mode_id := "M";
  othercases get_mode_id := "";
  end;
end;

@ The state of affairs at any semantic level can be represented by
five values:

\yskip\hang|mode| is the number representing the semantic mode, as
just explained.

\yskip\hang|head| is a |pointer| to a list head for the list being built;
|link(head)| therefore points to the first element of the list, or
to |null| if the list is empty.

\yskip\hang|tail| is a |pointer| to the final node of the list being
built; thus, |tail=head| if and only if the list is empty.

\yskip\hang|prev_graf| is the number of lines of the current paragraph that
have already been put into the present vertical list.

\yskip\hang|aux| is an auxiliary |memory_word| that gives further information
that is needed to characterize the situation.

\yskip\noindent
In vertical mode, |aux| is also known as |prev_depth|; it is the scaled
value representing the depth of the previous box, for use in baseline
calculations, or it is |<=-1000|pt if the next box on the vertical list is to
be exempt from baseline calculations.  In horizontal mode, |aux| is also
known as |space_factor|; it holds the current space factor used in
spacing calculations. In math mode, |aux| is also known as |incompleat_noad|;
if not |null|, it points to a record that represents the numerator of a
generalized fraction for which the denominator is currently being formed
in the current list.

There is also a sixth quantity, |mode_line|, which correlates
the semantic nest with the user's input; |mode_line| contains the source
line number at which the current level of nesting was entered. The negative
of this line number is the |mode_line| at the level of the
user's output routine.

A seventh quantity, |eTeX_aux|, is used by the extended features \eTeX.
In math mode it is known as |delim_ptr| and points to the most
recent |fence_noad|  of a |math_left_group|.

In horizontal mode, the |prev_graf| field is used for initial language data.

The semantic nest is an array called |nest| that holds the |mode|, |head|,
|tail|, |prev_graf|, |aux|, and |mode_line| values for all semantic levels
below the currently active one. Information about the currently active
level is kept in the global quantities |mode|, |head|, |tail|, |prev_graf|,
|aux|, and |mode_line|, which live in a \PASCAL\ record that is ready to
be pushed onto |nest| if necessary.

The math field is used by various bits and pieces in |math.c|

@d ignore_depth==-65536000 {magic dimension value to mean `ignore me'}

@<Types...@>=
@!list_state_record=record@!mode_field:-mmode..mmode;@+
  @!head_field,@!tail_field: pointer;
  @!eTeX_aux_field: pointer;
  @!pg_field,@!ml_field: integer;@+
  @!aux_field: memory_word;
  @!dirs_field: halfword;
  @!math_field: integer;
  @!math_style_field: integer;
  end;

@ @d mode==cur_list.mode_field {current mode}
@d head==cur_list.head_field {header node of current list}
@d tail==cur_list.tail_field {final node on current list}
@d eTeX_aux==cur_list.eTeX_aux_field {auxiliary data for \eTeX}
@d prev_graf==cur_list.pg_field {number of paragraph lines accumulated}
@d aux==cur_list.aux_field {auxiliary data about the current list}
@d prev_depth==aux.sc {the name of |aux| in vertical mode}
@d space_factor==aux.hh.lh {part of |aux| in horizontal mode}
@d incompleat_noad==aux.int {the name of |aux| in math mode}
@d mode_line==cur_list.ml_field {source file line number at beginning of list}
@d dir_save==cur_list.dirs_field {dir stack when a paragraph is interrupted}

@<Glob...@>=
@!nest:array[0..nest_size] of list_state_record;
@!nest_ptr:0..nest_size; {first unused location of |nest|}
@!max_nest_stack:0..nest_size; {maximum of |nest_ptr| when pushing}
@!cur_list:list_state_record; {the ``top'' semantic state}
@!shown_mode:-mmode..mmode; {most recent mode shown by \.{\\tracingcommands}}
@!save_tail: pointer; {save |tail| so we can examine whether we have an auto
                       kern before a glue}

@ Here is a common way to make the current list grow:

@p
procedure tail_append(p:pointer);
begin
vlink(tail):=p; tail:=vlink(tail);
end;
@#
procedure new_tail_append(p:pointer);
begin
couple_nodes(tail,p); tail:=vlink(tail);
end;
@#
function pop_tail:pointer;
label exit;
var n,r:pointer;
begin
  if tail<>head then begin
    r:=tail;
    if vlink(alink(tail))=tail then
      n:=alink(tail)
    else begin
      n:=head;
      while vlink(n)<>tail do n:=vlink(n);
      end;
    flush_node(tail);
    tail:=n;
    vlink(n):=null;
    pop_tail:=r;
    end
  else
    pop_tail:=null;
exit:end;


@ We will see later that the vertical list at the bottom semantic level is split
into two parts; the ``current page'' runs from |page_head| to |page_tail|,
and the ``contribution list'' runs from |contrib_head| to |tail| of
semantic level zero. The idea is that contributions are first formed in
vertical mode, then ``contributed'' to the current page (during which time
the page-breaking decisions are made). For now, we don't need to know
any more details about the page-building process.

@<Set init...@>=
nest_ptr:=0; max_nest_stack:=0;
mode:=vmode; head:=contrib_head; tail:=contrib_head;
eTeX_aux:=null;
prev_depth:=ignore_depth; mode_line:=0;
prev_graf:=0; shown_mode:=0;
dir_save:=null; init_math_fields;
@<Start a new current page@>;

@ @p @<LOCAL: Declare |make_local_par_node|@>;

@ @p @<DIR: Declare |new_dir|@>;

@ When \TeX's work on one level is interrupted, the state is saved by
calling |push_nest|. This routine changes |head| and |tail| so that
a new (empty) list is begun; it does not change |mode| or |aux|.

@p procedure push_nest; {enter a new semantic level, save the old}
begin if nest_ptr>max_nest_stack then
  begin max_nest_stack:=nest_ptr;
  if nest_ptr=nest_size then overflow("semantic nest size",nest_size);
@:TeX capacity exceeded semantic nest size}{\quad semantic nest size@>
  end;
nest[nest_ptr]:=cur_list; {stack the record}
incr(nest_ptr); head:=new_node(temp_node,0); tail:=head; prev_graf:=0; mode_line:=line;
dir_save:=null; init_math_fields;
eTeX_aux:=null;
end;

@ Conversely, when \TeX\ is finished on the current level, the former
state is restored by calling |pop_nest|. This routine will never be
called at the lowest semantic level, nor will it be called unless |head|
is a node that should be returned to free memory.

@p procedure pop_nest; {leave a semantic level, re-enter the old}
begin
flush_node(head); decr(nest_ptr); cur_list:=nest[nest_ptr];
end;

@ Here is a procedure that displays what \TeX\ is working on, at all levels.

@p procedure@?print_totals; forward;@t\2@>
procedure show_activities;
var p:0..nest_size; {index into |nest|}
@!m:-mmode..mmode; {mode}
@!a:memory_word; {auxiliary}
@!q,@!r:pointer; {for showing the current page}
@!t:integer; {ditto}
begin nest[nest_ptr]:=cur_list; {put the top level into the array}
print_nl(""); print_ln;
for p:=nest_ptr downto 0 do
  begin m:=nest[p].mode_field; a:=nest[p].aux_field;
  print_nl("### "); print_mode(m);
  print(" entered at line "); print_int(abs(nest[p].ml_field));
  if m=hmode then if nest[p].pg_field <> @'40600000 then
    begin print(" (language"); print_int(nest[p].pg_field mod @'200000);
    print(":hyphenmin"); print_int(nest[p].pg_field div @'20000000);
    print_char(","); print_int((nest[p].pg_field div @'200000) mod @'100);
    print_char(")");
    end;
  if nest[p].ml_field<0 then print(" (\output routine)");
  if p=0 then
    begin @<Show the status of the current page@>;
    if vlink(contrib_head)<>null then
      print_nl("### recent contributions:");
    end;
  show_box(vlink(nest[p].head_field));
  @<Show the auxiliary field, |a|@>;
  end;
end;

@ @<Show the auxiliary...@>=
case abs(m) div (max_command+1) of
0: begin print_nl("prevdepth ");
  if a.sc<=pdf_ignored_dimen then print("ignored")
  else print_scaled(a.sc);
  if nest[p].pg_field<>0 then
    begin print(", prevgraf ");
    print_int(nest[p].pg_field); print(" line");
    if nest[p].pg_field<>1 then print_char("s");
    end;
  end;
1: begin print_nl("spacefactor "); print_int(a.hh.lh);
  if m>0 then@+ if a.hh.rh>0 then
    begin print(", current language "); print_int(a.hh.rh);@+
    end;
  end;
2: if a.int<>null then
  begin print("this will be denominator of:"); show_box(a.int);@+
  end;
end {there are no other cases}

@* \[17] The table of equivalents.
Now that we have studied the data structures for \TeX's semantic routines,
we ought to consider the data structures used by its syntactic routines. In
other words, our next concern will be
the tables that \TeX\ looks at when it is scanning
what the user has written.

The biggest and most important such table is called |eqtb|. It holds the
current ``equivalents'' of things; i.e., it explains what things mean
or what their current values are, for all quantities that are subject to
the nesting structure provided by \TeX's grouping mechanism. There are six
parts to |eqtb|:

\yskip\hangg 1) |eqtb[null_cs]| holds the current equivalent of the
zero-length control sequence.

\yskip\hangg 2) |eqtb[hash_base..(glue_base-1)]| holds the current
equivalents of single- and multiletter control sequences.

\yskip\hangg 3) |eqtb[glue_base..(local_base-1)]| holds the current
equivalents of glue parameters like the current baselineskip.

\yskip\hangg 4) |eqtb[local_base..(int_base-1)]| holds the current
equivalents of local halfword quantities like the current box registers,
the current ``catcodes,'' the current font, and a pointer to the current
paragraph shape.

\yskip\hangg 5) |eqtb[int_base..(dimen_base-1)]| holds the current
equivalents of fullword integer parameters like the current hyphenation
penalty.

\yskip\hangg 6) |eqtb[dimen_base..eqtb_size]| holds the current equivalents
of fullword dimension parameters like the current hsize or amount of
hanging indentation.

\yskip\noindent Note that, for example, the current amount of
baselineskip glue is determined by the setting of a particular location
in region~3 of |eqtb|, while the current meaning of the control sequence
`\.{\\baselineskip}' (which might have been changed by \.{\\def} or
\.{\\let}) appears in region~2.

@ Each entry in |eqtb| is a |memory_word|. Most of these words are of type
|two_halves|, and subdivided into three fields:

\yskip\hangg 1) The |eq_level| (a quarterword) is the level of grouping at
which this equivalent was defined. If the level is |level_zero|, the
equivalent has never been defined; |level_one| refers to the outer level
(outside of all groups), and this level is also used for global
definitions that never go away. Higher levels are for equivalents that
will disappear at the end of their group.  @^global definitions@>

\yskip\hangg 2) The |eq_type| (another quarterword) specifies what kind of
entry this is. There are many types, since each \TeX\ primitive like
\.{\\hbox}, \.{\\def}, etc., has its own special code. The list of
command codes above includes all possible settings of the |eq_type| field.

\yskip\hangg 3) The |equiv| (a halfword) is the current equivalent value.
This may be a font number, a pointer into |mem|, or a variety of other
things.

@d eq_level_field(#)==#.hh.b1
@d eq_type_field(#)==#.hh.b0
@d equiv_field(#)==#.hh.rh
@d eq_level(#)==eq_level_field(eqtb[#]) {level of definition}
@d eq_type(#)==eq_type_field(eqtb[#]) {command code for equivalent}
@d equiv(#)==equiv_field(eqtb[#]) {equivalent value}
@d level_zero=min_quarterword {level for undefined quantities}
@d level_one=level_zero+1 {outermost level for defined quantities}

@ Many locations in |eqtb| have symbolic names. The purpose of the next
paragraphs is to define these names, and to set up the initial values of the
equivalents.

In the first region we have a single entry for the `null csname' of
length zero. In luatex, the active characters and and single-letter
control sequence names are part of the next region.

Then comes region~2, which corresponds to the hash table that we will
define later.  The maximum address in this region is used for a dummy
control sequence that is perpetually undefined. There also are several
locations for control sequences that are perpetually defined
(since they are used in error recovery).

@d null_cs=1 {equivalent of \.{\\csname\\endcsname}}
@d hash_base=null_cs+1 {beginning of region 2, for the hash table}
@d frozen_control_sequence=hash_base+hash_size {for error recovery}
@d frozen_protection=frozen_control_sequence {inaccessible but definable}
@d frozen_cr=frozen_control_sequence+1 {permanent `\.{\\cr}'}
@d frozen_end_group=frozen_control_sequence+2 {permanent `\.{\\endgroup}'}
@d frozen_right=frozen_control_sequence+3 {permanent `\.{\\right}'}
@d frozen_fi=frozen_control_sequence+4 {permanent `\.{\\fi}'}
@d frozen_end_template=frozen_control_sequence+5 {permanent `\.{\\endtemplate}'}
@d frozen_endv=frozen_control_sequence+6 {second permanent `\.{\\endtemplate}'}
@d frozen_relax=frozen_control_sequence+7 {permanent `\.{\\relax}'}
@d end_write=frozen_control_sequence+8 {permanent `\.{\\endwrite}'}
@d frozen_dont_expand=frozen_control_sequence+9
  {permanent `\.{\\notexpanded:}'}
@d frozen_primitive=frozen_control_sequence+11
  {permanent `\.{\\pdfprimitive}'}
@d frozen_special=frozen_control_sequence+12
  {permanent `\.{\\special}'}
@d frozen_null_font=frozen_control_sequence+13
  {permanent `\.{\\nullfont}'}
@d font_id_base=frozen_null_font-font_base
  {begins table of |number_fonts| permanent font identifiers}
@d frozen_null_ocp=frozen_null_font+number_fonts
  {permanent `\.{\\nullocp}'}
@d ocp_id_base=frozen_null_ocp-ocp_base
  {begins table of |number_ocps| permanent ocp identifiers}
@d frozen_null_ocp_list=frozen_null_ocp+number_ocps
  {permanent `\.{\\nullocplist}'}
@d ocp_list_id_base=frozen_null_ocp_list-ocp_list_base
  {begins table of |number_ocp_lists| permanent ocp list identifiers}
@d undefined_control_sequence=frozen_null_ocp_list+number_ocp_lists
@d glue_base=undefined_control_sequence+1 {beginning of region 3}

@<Initialize table entries...@>=
eq_type(undefined_control_sequence):=undefined_cs;
equiv(undefined_control_sequence):=null;
eq_level(undefined_control_sequence):=level_zero;
for k:=null_cs to undefined_control_sequence-1 do
  eqtb[k]:=eqtb[undefined_control_sequence];

@ Create a C version of |undefined_control_sequence|.

@<Global...@>=
@!static_undefined_control_sequence:integer;

@ @<Set init...@>=
static_undefined_control_sequence:=undefined_control_sequence;

@ Here is a routine that displays the current meaning of an |eqtb| entry
in region 1 or~2. (Similar routines for the other regions will appear
below.)

@<Show equivalent |n|, in region 1 or 2@>=
begin sprint_cs(n); print_char("="); print_cmd_chr(eq_type(n),equiv(n));
if eq_type(n)>=call then
  begin print_char(":"); show_token_list(link(equiv(n)),null,32);
  end;
end

@ Region 3 of |eqtb| contains the |number_regs| \.{\\skip} registers, as well as the
glue parameters defined here. It is important that the ``muskip''
parameters have larger numbers than the others.

@d line_skip_code=0 {interline glue if |baseline_skip| is infeasible}
@d baseline_skip_code=1 {desired glue between baselines}
@d par_skip_code=2 {extra glue just above a paragraph}
@d above_display_skip_code=3 {extra glue just above displayed math}
@d below_display_skip_code=4 {extra glue just below displayed math}
@d above_display_short_skip_code=5
  {glue above displayed math following short lines}
@d below_display_short_skip_code=6
  {glue below displayed math following short lines}
@d left_skip_code=7 {glue at left of justified lines}
@d right_skip_code=8 {glue at right of justified lines}
@d top_skip_code=9 {glue at top of main pages}
@d split_top_skip_code=10 {glue at top of split pages}
@d tab_skip_code=11 {glue between aligned entries}
@d space_skip_code=12 {glue between words (if not |zero_glue|)}
@d xspace_skip_code=13 {glue after sentences (if not |zero_glue|)}
@d par_fill_skip_code=14 {glue on last line of paragraph}
@d thin_mu_skip_code=15 {thin space in math formula}
@d med_mu_skip_code=16 {medium space in math formula}
@d thick_mu_skip_code=17 {thick space in math formula}
@d glue_pars=18 {total number of glue parameters}
@d skip_base=glue_base+glue_pars {table of |number_regs| ``skip'' registers}
@d mu_skip_base=skip_base+number_regs {table of |number_regs| ``muskip'' registers}
@d local_base=mu_skip_base+number_regs {beginning of region 4}
@#
@d skip(#)==equiv(skip_base+#) {|mem| location of glue specification}
@d mu_skip(#)==equiv(mu_skip_base+#) {|mem| location of math glue spec}
@d glue_par(#)==equiv(glue_base+#) {|mem| location of glue specification}
@d line_skip==glue_par(line_skip_code)
@d baseline_skip==glue_par(baseline_skip_code)
@d par_skip==glue_par(par_skip_code)
@d above_display_skip==glue_par(above_display_skip_code)
@d below_display_skip==glue_par(below_display_skip_code)
@d above_display_short_skip==glue_par(above_display_short_skip_code)
@d below_display_short_skip==glue_par(below_display_short_skip_code)
@d left_skip==glue_par(left_skip_code)
@d right_skip==glue_par(right_skip_code)
@d top_skip==glue_par(top_skip_code)
@d split_top_skip==glue_par(split_top_skip_code)
@d tab_skip==glue_par(tab_skip_code)
@d space_skip==glue_par(space_skip_code)
@d xspace_skip==glue_par(xspace_skip_code)
@d par_fill_skip==glue_par(par_fill_skip_code)
@d thin_mu_skip==glue_par(thin_mu_skip_code)
@d med_mu_skip==glue_par(med_mu_skip_code)
@d thick_mu_skip==glue_par(thick_mu_skip_code)

@<Current |mem| equivalent of glue parameter number |n|@>=glue_par(n)

@ @<Set init...@>=
static_local_base:=local_base;
static_glue_base:=glue_base;

@ Sometimes we need to convert \TeX's internal code numbers into symbolic
form. The |print_skip_param| routine gives the symbolic name of a glue
parameter.

@<Declare the procedure called |print_skip_param|@>=
procedure print_skip_param(@!n:integer);
begin case n of
line_skip_code: print_esc("lineskip");
baseline_skip_code: print_esc("baselineskip");
par_skip_code: print_esc("parskip");
above_display_skip_code: print_esc("abovedisplayskip");
below_display_skip_code: print_esc("belowdisplayskip");
above_display_short_skip_code: print_esc("abovedisplayshortskip");
below_display_short_skip_code: print_esc("belowdisplayshortskip");
left_skip_code: print_esc("leftskip");
right_skip_code: print_esc("rightskip");
top_skip_code: print_esc("topskip");
split_top_skip_code: print_esc("splittopskip");
tab_skip_code: print_esc("tabskip");
space_skip_code: print_esc("spaceskip");
xspace_skip_code: print_esc("xspaceskip");
par_fill_skip_code: print_esc("parfillskip");
thin_mu_skip_code: print_esc("thinmuskip");
med_mu_skip_code: print_esc("medmuskip");
thick_mu_skip_code: print_esc("thickmuskip");
othercases print("[unknown glue parameter!]")
endcases;
end;

@ The symbolic names for glue parameters are put into \TeX's hash table
by using the routine called |primitive|, defined below. Let us enter them
now, so that we don't have to list all those parameter names anywhere else.

@<Put each of \TeX's primitives into the hash table@>=
primitive_tex("lineskip",assign_glue,glue_base+line_skip_code,glue_base);@/
@!@:line_skip_}{\.{\\lineskip} primitive@>
primitive_tex("baselineskip",assign_glue,glue_base+baseline_skip_code,glue_base);@/
@!@:baseline_skip_}{\.{\\baselineskip} primitive@>
primitive_tex("parskip",assign_glue,glue_base+par_skip_code,glue_base);@/
@!@:par_skip_}{\.{\\parskip} primitive@>
primitive_tex("abovedisplayskip",assign_glue,glue_base+above_display_skip_code,glue_base);@/
@!@:above_display_skip_}{\.{\\abovedisplayskip} primitive@>
primitive_tex("belowdisplayskip",assign_glue,glue_base+below_display_skip_code,glue_base);@/
@!@:below_display_skip_}{\.{\\belowdisplayskip} primitive@>
primitive_tex("abovedisplayshortskip",assign_glue,glue_base+above_display_short_skip_code,glue_base);@/
@!@:above_display_short_skip_}{\.{\\abovedisplayshortskip} primitive@>
primitive_tex("belowdisplayshortskip",assign_glue,glue_base+below_display_short_skip_code,glue_base);@/
@!@:below_display_short_skip_}{\.{\\belowdisplayshortskip} primitive@>
primitive_tex("leftskip",assign_glue,glue_base+left_skip_code,glue_base);@/
@!@:left_skip_}{\.{\\leftskip} primitive@>
primitive_tex("rightskip",assign_glue,glue_base+right_skip_code,glue_base);@/
@!@:right_skip_}{\.{\\rightskip} primitive@>
primitive_tex("topskip",assign_glue,glue_base+top_skip_code,glue_base);@/
@!@:top_skip_}{\.{\\topskip} primitive@>
primitive_tex("splittopskip",assign_glue,glue_base+split_top_skip_code,glue_base);@/
@!@:split_top_skip_}{\.{\\splittopskip} primitive@>
primitive_tex("tabskip",assign_glue,glue_base+tab_skip_code,glue_base);@/
@!@:tab_skip_}{\.{\\tabskip} primitive@>
primitive_tex("spaceskip",assign_glue,glue_base+space_skip_code,glue_base);@/
@!@:space_skip_}{\.{\\spaceskip} primitive@>
primitive_tex("xspaceskip",assign_glue,glue_base+xspace_skip_code,glue_base);@/
@!@:xspace_skip_}{\.{\\xspaceskip} primitive@>
primitive_tex("parfillskip",assign_glue,glue_base+par_fill_skip_code,glue_base);@/
@!@:par_fill_skip_}{\.{\\parfillskip} primitive@>
primitive_tex("thinmuskip",assign_mu_glue,glue_base+thin_mu_skip_code,glue_base+thin_mu_skip_code);@/
@!@:thin_mu_skip_}{\.{\\thinmuskip} primitive@>
primitive_tex("medmuskip",assign_mu_glue,glue_base+med_mu_skip_code,glue_base+thin_mu_skip_code);@/
@!@:med_mu_skip_}{\.{\\medmuskip} primitive@>
primitive_tex("thickmuskip",assign_mu_glue,glue_base+thick_mu_skip_code,glue_base+thin_mu_skip_code);@/
@!@:thick_mu_skip_}{\.{\\thickmuskip} primitive@>

@ All glue parameters and registers are initially `\.{0pt plus0pt minus0pt}'.

@<Initialize table entries...@>=
equiv(glue_base):=zero_glue; eq_level(glue_base):=level_one;
eq_type(glue_base):=glue_ref;
for k:=glue_base+1 to local_base-1 do eqtb[k]:=eqtb[glue_base];
glue_ref_count(zero_glue):=glue_ref_count(zero_glue)+local_base-glue_base;

@ @<Show equivalent |n|, in region 3@>=
begin
if n<skip_base then
  begin print_skip_param(n-glue_base); print_char("=");
  if n<glue_base+thin_mu_skip_code then print_spec(equiv(n),"pt")
  else print_spec(equiv(n),"mu");
  end
else if n<mu_skip_base then
  begin print_esc("skip"); print_int(n-skip_base); print_char("=");
  print_spec(equiv(n),"pt");
  end
else  begin print_esc("muskip"); print_int(n-mu_skip_base); print_char("=");
  print_spec(equiv(n),"mu");
  end;
end

@ Region 4 of |eqtb| contains the local quantities defined here. The
bulk of this region is taken up by five tables that are indexed by eight-bit
characters; these tables are important to both the syntactic and semantic
portions of \TeX. There are also a bunch of special things like font and
token parameters, as well as the tables of \.{\\toks} and \.{\\box}
registers.

@d par_shape_loc=local_base {specifies paragraph shape}
@d output_routine_loc=local_base+1 {points to token list for \.{\\output}}
@d every_par_loc=local_base+2 {points to token list for \.{\\everypar}}
@d every_math_loc=local_base+3 {points to token list for \.{\\everymath}}
@d every_display_loc=local_base+4 {points to token list for \.{\\everydisplay}}
@d every_hbox_loc=local_base+5 {points to token list for \.{\\everyhbox}}
@d every_vbox_loc=local_base+6 {points to token list for \.{\\everyvbox}}
@d every_job_loc=local_base+7 {points to token list for \.{\\everyjob}}
@d every_cr_loc=local_base+8 {points to token list for \.{\\everycr}}
@d err_help_loc=local_base+9 {points to token list for \.{\\errhelp}}
@d tex_toks=local_base+10 {end of \TeX's token list parameters}
@#
@d pdftex_first_loc       = tex_toks {base for \pdfTeX's token list parameters}
@d pdf_pages_attr_loc     = pdftex_first_loc + 0 {points to token list for \.{\\pdfpagesattr}}
@d pdf_page_attr_loc      = pdftex_first_loc + 1 {points to token list for \.{\\pdfpageattr}}
@d pdf_page_resources_loc = pdftex_first_loc + 2 {points to token list for \.{\\pdfpageresources}}
@d pdf_pk_mode_loc        = pdftex_first_loc + 3 {points to token list for \.{\\pdfpkmode}}
@d pdf_toks=pdftex_first_loc+4 {end of \pdfTeX's token list parameters}
@#
@d etex_toks_base=pdf_toks {base for \eTeX's token list parameters}
@d every_eof_loc=etex_toks_base {points to token list for \.{\\everyeof}}
@d etex_toks=etex_toks_base+1 {end of \eTeX's token list parameters}
@#
@d ocp_trace_level_base=etex_toks
@d ocp_active_number_base=ocp_trace_level_base+1
@d ocp_active_min_ptr_base = ocp_active_number_base+1
@d ocp_active_max_ptr_base = ocp_active_min_ptr_base+1
@d ocp_active_base = ocp_active_max_ptr_base+1
@d toks_base       = ocp_active_base+max_active_ocp_lists
   {table of |number_regs| token list registers}
@#
@d etex_pen_base=toks_base+number_regs {start of table of \eTeX's penalties}
@d inter_line_penalties_loc=etex_pen_base {additional penalties between lines}
@d club_penalties_loc=etex_pen_base+1 {penalties for creating club lines}
@d widow_penalties_loc=etex_pen_base+2 {penalties for creating widow lines}
@d display_widow_penalties_loc=etex_pen_base+3 {ditto, just before a display}
@d etex_pens=etex_pen_base+4 {end of table of \eTeX's penalties}
@#
@d local_left_box_base=etex_pens
@d local_right_box_base=local_left_box_base+1
@d box_base=local_right_box_base+1 {table of |number_regs| box registers}
@d cur_font_loc=box_base+number_regs {internal font number outside math mode}
@d math_param_base=cur_font_loc+1  {current math parameter data index }
@d cat_code_base=math_param_base+1 {current category code data index }
@d lc_code_base=cat_code_base+1 {table of |number_chars| lowercase mappings}
@d uc_code_base=lc_code_base+1 {table of |number_chars| uppercase mappings}
@d sf_code_base=uc_code_base+1 {table of |number_chars| spacefactor mappings}
@d math_code_base=sf_code_base+1 {table of |number_chars| math mode mappings}
@d int_base=math_code_base+1 {beginning of region 5}
@#
@d par_shape_ptr==equiv(par_shape_loc)
@d output_routine==equiv(output_routine_loc)
@d every_par==equiv(every_par_loc)
@d every_math==equiv(every_math_loc)
@d every_display==equiv(every_display_loc)
@d every_hbox==equiv(every_hbox_loc)
@d every_vbox==equiv(every_vbox_loc)
@d every_job==equiv(every_job_loc)
@d every_cr==equiv(every_cr_loc)
@d err_help==equiv(err_help_loc)
@d pdf_pages_attr==equiv(pdf_pages_attr_loc)
@d pdf_page_attr==equiv(pdf_page_attr_loc)
@d pdf_page_resources==equiv(pdf_page_resources_loc)
@d pdf_pk_mode==equiv(pdf_pk_mode_loc)
@d toks(#)==equiv(toks_base+#)
@d local_left_box==equiv(local_left_box_base)
@d local_right_box==equiv(local_right_box_base)
@d box(#)==equiv(box_base+#)
@d cur_font==equiv(cur_font_loc)

@<Put each...@>=
primitive_tex("output",assign_toks,output_routine_loc,local_base);
@!@:output_}{\.{\\output} primitive@>
primitive_tex("everypar",assign_toks,every_par_loc,local_base);
@!@:every_par_}{\.{\\everypar} primitive@>
primitive_tex("everymath",assign_toks,every_math_loc,local_base);
@!@:every_math_}{\.{\\everymath} primitive@>
primitive_tex("everydisplay",assign_toks,every_display_loc,local_base);
@!@:every_display_}{\.{\\everydisplay} primitive@>
primitive_tex("everyhbox",assign_toks,every_hbox_loc,local_base);
@!@:every_hbox_}{\.{\\everyhbox} primitive@>
primitive_tex("everyvbox",assign_toks,every_vbox_loc,local_base);
@!@:every_vbox_}{\.{\\everyvbox} primitive@>
primitive_tex("everyjob",assign_toks,every_job_loc,local_base);
@!@:every_job_}{\.{\\everyjob} primitive@>
primitive_tex("everycr",assign_toks,every_cr_loc,local_base);
@!@:every_cr_}{\.{\\everycr} primitive@>
primitive_tex("errhelp",assign_toks,err_help_loc,local_base);
@!@:err_help_}{\.{\\errhelp} primitive@>
primitive_pdftex("pdfpagesattr",assign_toks,pdf_pages_attr_loc,local_base);
@!@:pdf_pages_attr_}{\.{\\pdfpagesattr} primitive@>
primitive_pdftex("pdfpageattr",assign_toks,pdf_page_attr_loc,local_base);
@!@:pdf_page_attr_}{\.{\\pdfpageattr} primitive@>
primitive_pdftex("pdfpageresources",assign_toks,pdf_page_resources_loc,local_base);
@!@:pdf_page_resources_}{\.{\\pdfpageresources} primitive@>
primitive_pdftex("pdfpkmode",assign_toks,pdf_pk_mode_loc,local_base);
@!@:pdf_pk_mode_}{\.{\\pdfpkmode} primitive@>


@ We initialize most things to null or undefined values. An undefined font
is represented by the internal code |font_base|.

However, the character code tables are given initial values based on the
conventional interpretation of ASCII code. These initial values should
not be changed when \TeX\ is adapted for use with non-English languages;
all changes to the initialization conventions should be made in format
packages, not in \TeX\ itself, so that global interchange of formats is
possible.

@d null_font==font_base
@d null_ocp==ocp_base
@d null_ocp_list==ocp_list_base
@d var_code==7 {math code meaning ``use the current family''}

@<Initialize table entries...@>=
par_shape_ptr:=null; eq_type(par_shape_loc):=shape_ref;
eq_level(par_shape_loc):=level_one;@/
for k:=etex_pen_base to etex_pens-1 do
  eqtb[k]:=eqtb[par_shape_loc];
for k:=output_routine_loc to toks_base+biggest_reg do
  eqtb[k]:=eqtb[undefined_control_sequence];
box(0):=null; eq_type(box_base):=box_ref; eq_level(box_base):=level_one;
for k:=box_base+1 to box_base+biggest_reg do eqtb[k]:=eqtb[box_base];
cur_font:=null_font; eq_type(cur_font_loc):=data;
eq_level(cur_font_loc):=level_one;@/
equiv(cat_code_base):=0; eq_type(cat_code_base):=data;
eq_level(cat_code_base):=level_one;@/
eqtb[math_param_base]:=eqtb[cat_code_base];
eqtb[lc_code_base] :=eqtb[cat_code_base];
eqtb[uc_code_base] :=eqtb[cat_code_base];
eqtb[sf_code_base] :=eqtb[cat_code_base];
eqtb[math_code_base]:=eqtb[cat_code_base];@/
cat_code_table:=0;
initialize_math_codes;
initialize_text_codes;
initex_cat_codes(0);
for k:="0" to "9" do set_math_code(k,tex_mathcode,var_code,0,k,level_one);@/
for k:="A" to "Z" do begin
  set_math_code(k,tex_mathcode,var_code,1,k,level_one);
  set_math_code((k+32),tex_mathcode,var_code,1,(k+32),level_one);@/
  set_lc_code(k,k+32,level_one); set_lc_code(k+32,k+32,level_one);@/
  set_uc_code(k,k,level_one);    set_uc_code(k+32,k,level_one);@/
  set_sf_code(k,999,level_one);
  end;

@ @<Set init...@>=
static_int_base:=int_base;

@ @<Show equivalent |n|, in region 4@>=
begin
if (n=par_shape_loc) or ((n>=etex_pen_base) and (n<etex_pens)) then
  begin if n=par_shape_loc then print_cmd_chr(set_tex_shape,n)
  else  print_cmd_chr(set_etex_shape,n);
  print_char("=");
  if equiv(n)=null then print_char("0")
  else if n>par_shape_loc then
    begin print_int(penalty(equiv(n))); print_char(" ");
    print_int(penalty(equiv(n)+1));
    if penalty(equiv(n))>1 then print_esc("ETC.");
    end
  else print_int(vinfo(par_shape_ptr+1));
  end
else if n<toks_base then
  {TH TODO make extra cases for ocps here! }
  begin print_cmd_chr(assign_toks,n); print_char("=");
  if equiv(n)<>null then show_token_list(link(equiv(n)),null,32);
  end
else if n<box_base then
  begin print_esc("toks"); print_int(n-toks_base); print_char("=");
  if equiv(n)<>null then show_token_list(link(equiv(n)),null,32);
  end
else if n<cur_font_loc then
  begin print_esc("box"); print_int(n-box_base); print_char("=");
  if equiv(n)=null then print("void")
  else  begin depth_threshold:=0; breadth_max:=1; show_node_list(equiv(n));
    end;
  end
else if n=cur_font_loc then @<Show the font identifier in |eqtb[n]|@>;
end

@ @<Show the font identifier in |eqtb[n]|@>=
begin print("current font"); print_char("=");@/
print_esc(hash[font_id_base+equiv(n)].rh);
  {that's |font_id_text(equiv(n))|}
end

@ Region 5 of |eqtb| contains the integer parameters and registers defined
here, as well as the |del_code| table. The latter table differs from the
|cat_code..math_code| tables that precede it, since delimiter codes are
fullword integers while the other kinds of codes occupy at most a
halfword. This is what makes region~5 different from region~4. We will
store the |eq_level| information in an auxiliary array of quarterwords
that will be defined later.

@d pretolerance_code=0 {badness tolerance before hyphenation}
@d tolerance_code=1 {badness tolerance after hyphenation}
@d line_penalty_code=2 {added to the badness of every line}
@d hyphen_penalty_code=3 {penalty for break after discretionary hyphen}
@d ex_hyphen_penalty_code=4 {penalty for break after explicit hyphen}
@d club_penalty_code=5 {penalty for creating a club line}
@d widow_penalty_code=6 {penalty for creating a widow line}
@d display_widow_penalty_code=7 {ditto, just before a display}
@d broken_penalty_code=8 {penalty for breaking a page at a broken line}
@d bin_op_penalty_code=9 {penalty for breaking after a binary operation}
@d rel_penalty_code=10 {penalty for breaking after a relation}
@d pre_display_penalty_code=11 {penalty for breaking just before a displayed formula}
@d post_display_penalty_code=12 {penalty for breaking just after a displayed formula}
@d inter_line_penalty_code=13 {additional penalty between lines}
@d double_hyphen_demerits_code=14 {demerits for double hyphen break}
@d final_hyphen_demerits_code=15 {demerits for final hyphen break}
@d adj_demerits_code=16 {demerits for adjacent incompatible lines}
@d mag_code=17 {magnification ratio}
@d delimiter_factor_code=18 {ratio for variable-size delimiters}
@d looseness_code=19 {change in number of lines for a paragraph}
@d time_code=20 {current time of day}
@d day_code=21 {current day of the month}
@d month_code=22 {current month of the year}
@d year_code=23 {current year of our Lord}
@d show_box_breadth_code=24 {nodes per level in |show_box|}
@d show_box_depth_code=25 {maximum level in |show_box|}
@d hbadness_code=26 {hboxes exceeding this badness will be shown by |hpack|}
@d vbadness_code=27 {vboxes exceeding this badness will be shown by |vpack|}
@d pausing_code=28 {pause after each line is read from a file}
@d tracing_online_code=29 {show diagnostic output on terminal}
@d tracing_macros_code=30 {show macros as they are being expanded}
@d tracing_stats_code=31 {show memory usage if \TeX\ knows it}
@d tracing_paragraphs_code=32 {show line-break calculations}
@d tracing_pages_code=33 {show page-break calculations}
@d tracing_output_code=34 {show boxes when they are shipped out}
@d tracing_lost_chars_code=35 {show characters that aren't in the font}
@d tracing_commands_code=36 {show command codes at |big_switch|}
@d tracing_restores_code=37 {show equivalents when they are restored}
@d uc_hyph_code=38 {hyphenate words beginning with a capital letter}
@d output_penalty_code=39 {penalty found at current page break}
@d max_dead_cycles_code=40 {bound on consecutive dead cycles of output}
@d hang_after_code=41 {hanging indentation changes after this many lines}
@d floating_penalty_code=42 {penalty for insertions heldover after a split}
@d global_defs_code=43 {override \.{\\global} specifications}
@d cur_fam_code=44 {current family}
@d escape_char_code=45 {escape character for token output}
@d default_hyphen_char_code=46 {value of \.{\\hyphenchar} when a font is loaded}
@d default_skew_char_code=47 {value of \.{\\skewchar} when a font is loaded}
@d end_line_char_code=48 {character placed at the right end of the buffer}
@d new_line_char_code=49 {character that prints as |print_ln|}
@d language_code=50 {current hyphenation table}
@d left_hyphen_min_code=51 {minimum left hyphenation fragment size}
@d right_hyphen_min_code=52 {minimum right hyphenation fragment size}
@d holding_inserts_code=53 {do not remove insertion nodes from \.{\\box255}}
@d error_context_lines_code=54 {maximum intermediate line pairs shown}
@d local_inter_line_penalty_code=55 {local \.{\\interlinepenalty}}
@d local_broken_penalty_code=56 {local \.{\\brokenpenalty}}
@d no_local_whatsits_code=57 {counts local whatsits}
@d no_local_dirs_code=58
@d level_local_dir_code=59
@d luastartup_id_code=60
@d disable_lig_code=61
@d disable_kern_code=62
@d cat_code_table_code=63
@d output_box_code=64
@d cur_lang_code=65 {current language id}
@d ex_hyphen_char_code=66
@d tex_int_pars=67 {total number of \.{\\TeX} + Aleph integer parameters}
@#
@d dir_base=int_base+tex_int_pars
@d page_direction_code=0
@d body_direction_code=1
@d par_direction_code=2
@d text_direction_code=3
@d math_direction_code=4
@d dir_pars=5
@#
@d pdftex_first_integer_code = tex_int_pars+dir_pars {base for \pdfTeX's integer parameters}
@d pdf_output_code           = pdftex_first_integer_code + 0 {switch on PDF output if positive}
@d pdf_compress_level_code   = pdftex_first_integer_code + 1 {compress level of streams}
@d pdf_decimal_digits_code   = pdftex_first_integer_code + 2 {digits after the decimal point of numbers}
@d pdf_move_chars_code       = pdftex_first_integer_code + 3 {move chars 0..31 to higher area if possible}
@d pdf_image_resolution_code = pdftex_first_integer_code + 4 {default image resolution}
@d pdf_pk_resolution_code    = pdftex_first_integer_code + 5 {default resolution of PK font}
@d pdf_unique_resname_code   = pdftex_first_integer_code + 6 {generate unique names for resouces}
@d pdf_option_always_use_pdfpagebox_code = pdftex_first_integer_code + 7 {if the PDF inclusion should always use a specific PDF page box}
@d pdf_option_pdf_inclusion_errorlevel_code = pdftex_first_integer_code + 8 {if the PDF inclusion should treat pdfs newer than |pdf_minor_version| as an error}
@d pdf_minor_version_code = pdftex_first_integer_code + 9 {fractional part of the PDF version produced}
@d pdf_force_pagebox_code = pdftex_first_integer_code + 10 {if the PDF inclusion should always use a specific PDF page box}
@d pdf_pagebox_code = pdftex_first_integer_code + 11 {default pagebox to use for PDF inclusion}
@d pdf_inclusion_errorlevel_code = pdftex_first_integer_code + 12 {if the PDF inclusion should treat pdfs newer than |pdf_minor_version| as an error}
@d pdf_gamma_code            = pdftex_first_integer_code + 13
@d pdf_image_gamma_code      = pdftex_first_integer_code + 14
@d pdf_image_hicolor_code    = pdftex_first_integer_code + 15
@d pdf_image_apply_gamma_code = pdftex_first_integer_code + 16
@d pdf_adjust_spacing_code   = pdftex_first_integer_code + 17 {level of spacing adjusting}
@d pdf_protrude_chars_code   = pdftex_first_integer_code + 18 {protrude chars at left/right edge of paragraphs}
@d pdf_tracing_fonts_code    = pdftex_first_integer_code + 19 {level of font detail in log}
@d pdf_objcompresslevel_code = pdftex_first_integer_code + 20 {activate object streams}
@d pdf_gen_tounicode_code    = pdftex_first_integer_code + 24 {generate ToUnicode for fonts?}
@d pdf_draftmode_code        = pdftex_first_integer_code + 25 {switch on draftmode if positive}
@d pdf_replace_font_code     = pdftex_first_integer_code + 26 {generate ToUnicode for fonts?}
@d pdf_inclusion_copy_font_code = pdftex_first_integer_code + 27 {generate ToUnicode for fonts?}
@d pdf_int_pars=pdftex_first_integer_code + 28 {total number of \pdfTeX's integer parameters}
@#
@d etex_int_base=pdf_int_pars {base for \eTeX's integer parameters}
@d tracing_assigns_code=etex_int_base {show assignments}
@d tracing_groups_code=etex_int_base+1 {show save/restore groups}
@d tracing_ifs_code=etex_int_base+2 {show conditionals}
@d tracing_scan_tokens_code=etex_int_base+3 {show pseudo file open and close}
@d tracing_nesting_code=etex_int_base+4 {show incomplete groups and ifs within files}
@d pre_display_direction_code=etex_int_base+5 {text direction preceding a display}
@d last_line_fit_code=etex_int_base+6 {adjustment for last line of paragraph}
@d saving_vdiscards_code=etex_int_base+7 {save items discarded from vlists}
@d saving_hyph_codes_code=etex_int_base+8 {save hyphenation codes for languages}
@d suppress_fontnotfound_error_code=etex_int_base+9 {surpress errors for missing fonts}
@d suppress_long_error_code=etex_int_base+10 {surpress errors for missing fonts}
@d suppress_ifcsname_error_code=etex_int_base+11 {surpress errors for failed \.{\\ifcsname}}
@d suppress_outer_error_code=etex_int_base+12 {surpress errors for \.{\\outer}}
@d etex_int_pars=etex_int_base+13 {total number of \eTeX's integer parameters}
@#
@d synctex_code=etex_int_pars { is synctex file generation enabled ? }
@d int_pars=synctex_code+1 {total number of integer parameters}
@d count_base=int_base+int_pars {|number_regs| user \.{\\count} registers}
@d attribute_base=count_base+number_regs {|number_attrs| user \.{\\attribute} registers}
@d del_code_base=attribute_base+number_attrs {|number_chars| delimiter code mappings}
@d dimen_base=del_code_base+1 {beginning of region 6}
@#
@d count(#)==eqtb[count_base+#].int
@d attribute(#)==eqtb[attribute_base+#].int
@d int_par(#)==eqtb[int_base+#].int {an integer parameter}
@d pretolerance==int_par(pretolerance_code)
@d tolerance==int_par(tolerance_code)
@d line_penalty==int_par(line_penalty_code)
@d hyphen_penalty==int_par(hyphen_penalty_code)
@d ex_hyphen_penalty==int_par(ex_hyphen_penalty_code)
@d club_penalty==int_par(club_penalty_code)
@d widow_penalty==int_par(widow_penalty_code)
@d display_widow_penalty==int_par(display_widow_penalty_code)
@d broken_penalty==int_par(broken_penalty_code)
@d bin_op_penalty==int_par(bin_op_penalty_code)
@d rel_penalty==int_par(rel_penalty_code)
@d pre_display_penalty==int_par(pre_display_penalty_code)
@d post_display_penalty==int_par(post_display_penalty_code)
@d inter_line_penalty==int_par(inter_line_penalty_code)
@d double_hyphen_demerits==int_par(double_hyphen_demerits_code)
@d final_hyphen_demerits==int_par(final_hyphen_demerits_code)
@d adj_demerits==int_par(adj_demerits_code)
@d mag==int_par(mag_code)
@d delimiter_factor==int_par(delimiter_factor_code)
@d looseness==int_par(looseness_code)
@d time==int_par(time_code)
@d day==int_par(day_code)
@d month==int_par(month_code)
@d year==int_par(year_code)
@d show_box_breadth==int_par(show_box_breadth_code)
@d show_box_depth==int_par(show_box_depth_code)
@d hbadness==int_par(hbadness_code)
@d vbadness==int_par(vbadness_code)
@d pausing==int_par(pausing_code)
@d tracing_online==int_par(tracing_online_code)
@d tracing_macros==int_par(tracing_macros_code)
@d tracing_stats==int_par(tracing_stats_code)
@d tracing_paragraphs==int_par(tracing_paragraphs_code)
@d tracing_pages==int_par(tracing_pages_code)
@d tracing_output==int_par(tracing_output_code)
@d tracing_lost_chars==int_par(tracing_lost_chars_code)
@d tracing_commands==int_par(tracing_commands_code)
@d tracing_restores==int_par(tracing_restores_code)
@d uc_hyph==int_par(uc_hyph_code)
@d output_penalty==int_par(output_penalty_code)
@d max_dead_cycles==int_par(max_dead_cycles_code)
@d hang_after==int_par(hang_after_code)
@d floating_penalty==int_par(floating_penalty_code)
@d global_defs==int_par(global_defs_code)
@d cur_fam==int_par(cur_fam_code)
@d escape_char==int_par(escape_char_code)
@d default_hyphen_char==int_par(default_hyphen_char_code)
@d default_skew_char==int_par(default_skew_char_code)
@d end_line_char==int_par(end_line_char_code)
@d new_line_char==int_par(new_line_char_code)
@d local_inter_line_penalty==int_par(local_inter_line_penalty_code)
@d local_broken_penalty==int_par(local_broken_penalty_code)
@d no_local_whatsits==int_par(no_local_whatsits_code)
@d no_local_dirs==int_par(no_local_dirs_code)
@d level_local_dir==int_par(level_local_dir_code)
@d dir_par(#)==eqtb[dir_base+#].int {a direction parameter}
@d page_direction==dir_par(page_direction_code)
@d body_direction==dir_par(body_direction_code)
@d par_direction==dir_par(par_direction_code)
@d text_direction==dir_par(text_direction_code)
@d math_direction==dir_par(math_direction_code)
@d language==int_par(language_code)
@d cur_lang==int_par(cur_lang_code)
@d ex_hyphen_char==int_par(ex_hyphen_char_code)
@d left_hyphen_min==int_par(left_hyphen_min_code)
@d right_hyphen_min==int_par(right_hyphen_min_code)
@d holding_inserts==int_par(holding_inserts_code)
@d error_context_lines==int_par(error_context_lines_code)
@d luastartup_id==int_par(luastartup_id_code)
@d disable_lig==int_par(disable_lig_code)
@d disable_kern==int_par(disable_kern_code)
@d cat_code_table==int_par(cat_code_table_code)
@d output_box==int_par(output_box_code)
@#
@d pdf_adjust_spacing   == int_par(pdf_adjust_spacing_code)
@d pdf_protrude_chars   == int_par(pdf_protrude_chars_code)
@d pdf_tracing_fonts    == int_par(pdf_tracing_fonts_code)
@d pdf_gen_tounicode    == int_par(pdf_gen_tounicode_code)
@d pdf_output           == int_par(pdf_output_code)
@d pdf_compress_level   == int_par(pdf_compress_level_code)
@d pdf_objcompresslevel == int_par(pdf_objcompresslevel_code)
@d pdf_decimal_digits   == int_par(pdf_decimal_digits_code)
@d pdf_move_chars       == int_par(pdf_move_chars_code)
@d pdf_image_resolution == int_par(pdf_image_resolution_code)
@d pdf_pk_resolution    == int_par(pdf_pk_resolution_code)
@d pdf_unique_resname   == int_par(pdf_unique_resname_code)
@d pdf_option_always_use_pdfpagebox == int_par(pdf_option_always_use_pdfpagebox_code)
@d pdf_option_pdf_inclusion_errorlevel == int_par(pdf_option_pdf_inclusion_errorlevel_code)
@d pdf_minor_version == int_par(pdf_minor_version_code)
@d pdf_force_pagebox == int_par(pdf_force_pagebox_code)
@d pdf_pagebox == int_par(pdf_pagebox_code)
@d pdf_inclusion_errorlevel == int_par(pdf_inclusion_errorlevel_code)
@d pdf_gamma            == int_par(pdf_gamma_code)
@d pdf_image_gamma      == int_par(pdf_image_gamma_code)
@d pdf_image_hicolor    == int_par(pdf_image_hicolor_code)
@d pdf_image_apply_gamma == int_par(pdf_image_apply_gamma_code)
@d pdf_draftmode        == int_par(pdf_draftmode_code)
@d pdf_inclusion_copy_font == int_par(pdf_inclusion_copy_font_code)
@d pdf_replace_font == int_par(pdf_replace_font_code)
@#
@d tracing_assigns==int_par(tracing_assigns_code)
@d tracing_groups==int_par(tracing_groups_code)
@d tracing_ifs==int_par(tracing_ifs_code)
@d tracing_scan_tokens==int_par(tracing_scan_tokens_code)
@d tracing_nesting==int_par(tracing_nesting_code)
@d pre_display_direction==int_par(pre_display_direction_code)
@d last_line_fit==int_par(last_line_fit_code)
@d saving_vdiscards==int_par(saving_vdiscards_code)
@d saving_hyph_codes==int_par(saving_hyph_codes_code)
@d suppress_fontnotfound_error==int_par(suppress_fontnotfound_error_code)
@d suppress_long_error==int_par(suppress_long_error_code)
@d suppress_ifcsname_error==int_par(suppress_ifcsname_error_code)
@d synctex==int_par(synctex_code)

@<Assign the values |depth_threshold:=show_box_depth|...@>=
depth_threshold:=show_box_depth;
breadth_max:=show_box_breadth


@ @<Set init...@>=
static_dimen_base:=dimen_base;

@ We can print the symbolic name of an integer parameter as follows.

@p procedure print_param(@!n:integer);
begin case n of
pretolerance_code:print_esc("pretolerance");
tolerance_code:print_esc("tolerance");
line_penalty_code:print_esc("linepenalty");
hyphen_penalty_code:print_esc("hyphenpenalty");
ex_hyphen_penalty_code:print_esc("exhyphenpenalty");
club_penalty_code:print_esc("clubpenalty");
widow_penalty_code:print_esc("widowpenalty");
display_widow_penalty_code:print_esc("displaywidowpenalty");
broken_penalty_code:print_esc("brokenpenalty");
bin_op_penalty_code:print_esc("binoppenalty");
rel_penalty_code:print_esc("relpenalty");
pre_display_penalty_code:print_esc("predisplaypenalty");
post_display_penalty_code:print_esc("postdisplaypenalty");
inter_line_penalty_code:print_esc("interlinepenalty");
double_hyphen_demerits_code:print_esc("doublehyphendemerits");
final_hyphen_demerits_code:print_esc("finalhyphendemerits");
adj_demerits_code:print_esc("adjdemerits");
mag_code:print_esc("mag");
delimiter_factor_code:print_esc("delimiterfactor");
looseness_code:print_esc("looseness");
time_code:print_esc("time");
day_code:print_esc("day");
month_code:print_esc("month");
year_code:print_esc("year");
show_box_breadth_code:print_esc("showboxbreadth");
show_box_depth_code:print_esc("showboxdepth");
hbadness_code:print_esc("hbadness");
vbadness_code:print_esc("vbadness");
pausing_code:print_esc("pausing");
tracing_online_code:print_esc("tracingonline");
tracing_macros_code:print_esc("tracingmacros");
tracing_stats_code:print_esc("tracingstats");
tracing_paragraphs_code:print_esc("tracingparagraphs");
tracing_pages_code:print_esc("tracingpages");
tracing_output_code:print_esc("tracingoutput");
tracing_lost_chars_code:print_esc("tracinglostchars");
tracing_commands_code:print_esc("tracingcommands");
tracing_restores_code:print_esc("tracingrestores");
uc_hyph_code:print_esc("uchyph");
output_penalty_code:print_esc("outputpenalty");
max_dead_cycles_code:print_esc("maxdeadcycles");
hang_after_code:print_esc("hangafter");
floating_penalty_code:print_esc("floatingpenalty");
global_defs_code:print_esc("globaldefs");
cur_fam_code:print_esc("fam");
escape_char_code:print_esc("escapechar");
default_hyphen_char_code:print_esc("defaulthyphenchar");
default_skew_char_code:print_esc("defaultskewchar");
end_line_char_code:print_esc("endlinechar");
new_line_char_code:print_esc("newlinechar");
language_code:print_esc("language");
cur_lang_code:print_esc("setlanguage");
ex_hyphen_char_code:print_esc("exhyphenchar");
left_hyphen_min_code:print_esc("lefthyphenmin");
right_hyphen_min_code:print_esc("righthyphenmin");
holding_inserts_code:print_esc("holdinginserts");
error_context_lines_code:print_esc("errorcontextlines");
luastartup_id_code:print_esc("luastartup");
disable_lig_code:print_esc("noligs");
disable_kern_code:print_esc("nokerns");
cat_code_table_code:print_esc("catcodetable");
output_box_code:print_esc("outputbox");
@#
local_inter_line_penalty_code: print_esc("localinterlinepenalty");
local_broken_penalty_code: print_esc("localbrokenpenalty");
{the next three do not have a matching primitive}
no_local_whatsits_code: print("[no_local_whatsits]");
no_local_dirs_code: print("[no_local_dirs]");
level_local_dir_code: print("[level_local_dir]");
@#
pdf_output_code:           print_esc("pdfoutput");
pdf_compress_level_code:   print_esc("pdfcompresslevel");
pdf_objcompresslevel_code: print_esc("pdfobjcompresslevel");
pdf_decimal_digits_code:   print_esc("pdfdecimaldigits");
pdf_move_chars_code:       print_esc("pdfmovechars");
pdf_image_resolution_code: print_esc("pdfimageresolution");
pdf_pk_resolution_code:    print_esc("pdfpkresolution");
pdf_unique_resname_code:   print_esc("pdfuniqueresname");
pdf_option_always_use_pdfpagebox_code: print_esc("pdfoptionalwaysusepdfpagebox");
pdf_option_pdf_inclusion_errorlevel_code: print_esc("pdfoptionpdfinclusionerrorlevel");
pdf_minor_version_code: print_esc("pdfminorversion");
pdf_force_pagebox_code: print_esc("pdfforcepagebox");
pdf_pagebox_code: print_esc("pdfpagebox");
pdf_inclusion_errorlevel_code: print_esc("pdfinclusionerrorlevel");
pdf_gamma_code:            print_esc("pdfgamma");
pdf_image_gamma_code:      print_esc("pdfimagegamma");
pdf_image_hicolor_code:    print_esc("pdfimagehicolor");
pdf_image_apply_gamma_code: print_esc("pdfimageapplygamma");
pdf_adjust_spacing_code:   print_esc("pdfadjustspacing");
pdf_protrude_chars_code:   print_esc("pdfprotrudechars");
pdf_tracing_fonts_code:    print_esc("pdftracingfonts");
pdf_gen_tounicode_code:    print_esc("pdfgentounicode");
pdf_draftmode_code:        print_esc("pdfdraftmode");
pdf_inclusion_copy_font_code:    print_esc("pdfinclusioncopyfonts");
pdf_replace_font_code:    print_esc("pdfreplacefont");
@/@<Cases for |print_param|@>@/
othercases begin print("[unknown integer parameter!]"); end
endcases;
end;

@ The integer parameter names must be entered into the hash table.

@<Put each...@>=
primitive_tex("pretolerance",assign_int,int_base+pretolerance_code,int_base);@/
@!@:pretolerance_}{\.{\\pretolerance} primitive@>
primitive_tex("tolerance",assign_int,int_base+tolerance_code,int_base);@/
@!@:tolerance_}{\.{\\tolerance} primitive@>
primitive_tex("linepenalty",assign_int,int_base+line_penalty_code,int_base);@/
@!@:line_penalty_}{\.{\\linepenalty} primitive@>
primitive_tex("hyphenpenalty",assign_int,int_base+hyphen_penalty_code,int_base);@/
@!@:hyphen_penalty_}{\.{\\hyphenpenalty} primitive@>
primitive_tex("exhyphenpenalty",assign_int,int_base+ex_hyphen_penalty_code,int_base);@/
@!@:ex_hyphen_penalty_}{\.{\\exhyphenpenalty} primitive@>
primitive_tex("clubpenalty",assign_int,int_base+club_penalty_code,int_base);@/
@!@:club_penalty_}{\.{\\clubpenalty} primitive@>
primitive_tex("widowpenalty",assign_int,int_base+widow_penalty_code,int_base);@/
@!@:widow_penalty_}{\.{\\widowpenalty} primitive@>
primitive_tex("displaywidowpenalty", assign_int,int_base+display_widow_penalty_code,int_base);@/
@!@:display_widow_penalty_}{\.{\\displaywidowpenalty} primitive@>
primitive_tex("brokenpenalty",assign_int,int_base+broken_penalty_code,int_base);@/
@!@:broken_penalty_}{\.{\\brokenpenalty} primitive@>
primitive_tex("binoppenalty",assign_int,int_base+bin_op_penalty_code,int_base);@/
@!@:bin_op_penalty_}{\.{\\binoppenalty} primitive@>
primitive_tex("relpenalty",assign_int,int_base+rel_penalty_code,int_base);@/
@!@:rel_penalty_}{\.{\\relpenalty} primitive@>
primitive_tex("predisplaypenalty",assign_int,int_base+pre_display_penalty_code,int_base);@/
@!@:pre_display_penalty_}{\.{\\predisplaypenalty} primitive@>
primitive_tex("postdisplaypenalty",assign_int,int_base+post_display_penalty_code,int_base);@/
@!@:post_display_penalty_}{\.{\\postdisplaypenalty} primitive@>
primitive_tex("interlinepenalty",assign_int,int_base+inter_line_penalty_code,int_base);@/
@!@:inter_line_penalty_}{\.{\\interlinepenalty} primitive@>
primitive_tex("doublehyphendemerits", assign_int,int_base+double_hyphen_demerits_code,int_base);@/
@!@:double_hyphen_demerits_}{\.{\\doublehyphendemerits} primitive@>
primitive_tex("finalhyphendemerits", assign_int,int_base+final_hyphen_demerits_code,int_base);@/
@!@:final_hyphen_demerits_}{\.{\\finalhyphendemerits} primitive@>
primitive_tex("adjdemerits",assign_int,int_base+adj_demerits_code,int_base);@/
@!@:adj_demerits_}{\.{\\adjdemerits} primitive@>
primitive_tex("mag",assign_int,int_base+mag_code,int_base);@/
@!@:mag_}{\.{\\mag} primitive@>
primitive_tex("delimiterfactor",assign_int,int_base+delimiter_factor_code,int_base);@/
@!@:delimiter_factor_}{\.{\\delimiterfactor} primitive@>
primitive_tex("looseness",assign_int,int_base+looseness_code,int_base);@/
@!@:looseness_}{\.{\\looseness} primitive@>
primitive_tex("time",assign_int,int_base+time_code,int_base);@/
@!@:time_}{\.{\\time} primitive@>
primitive_tex("day",assign_int,int_base+day_code,int_base);@/
@!@:day_}{\.{\\day} primitive@>
primitive_tex("month",assign_int,int_base+month_code,int_base);@/
@!@:month_}{\.{\\month} primitive@>
primitive_tex("year",assign_int,int_base+year_code,int_base);@/
@!@:year_}{\.{\\year} primitive@>
primitive_tex("showboxbreadth",assign_int,int_base+show_box_breadth_code,int_base);@/
@!@:show_box_breadth_}{\.{\\showboxbreadth} primitive@>
primitive_tex("showboxdepth",assign_int,int_base+show_box_depth_code,int_base);@/
@!@:show_box_depth_}{\.{\\showboxdepth} primitive@>
primitive_tex("hbadness",assign_int,int_base+hbadness_code,int_base);@/
@!@:hbadness_}{\.{\\hbadness} primitive@>
primitive_tex("vbadness",assign_int,int_base+vbadness_code,int_base);@/
@!@:vbadness_}{\.{\\vbadness} primitive@>
primitive_tex("pausing",assign_int,int_base+pausing_code,int_base);@/
@!@:pausing_}{\.{\\pausing} primitive@>
primitive_tex("tracingonline",assign_int,int_base+tracing_online_code,int_base);@/
@!@:tracing_online_}{\.{\\tracingonline} primitive@>
primitive_tex("tracingmacros",assign_int,int_base+tracing_macros_code,int_base);@/
@!@:tracing_macros_}{\.{\\tracingmacros} primitive@>
primitive_tex("tracingstats",assign_int,int_base+tracing_stats_code,int_base);@/
@!@:tracing_stats_}{\.{\\tracingstats} primitive@>
primitive_tex("tracingparagraphs",assign_int,int_base+tracing_paragraphs_code,int_base);@/
@!@:tracing_paragraphs_}{\.{\\tracingparagraphs} primitive@>
primitive_tex("tracingpages",assign_int,int_base+tracing_pages_code,int_base);@/
@!@:tracing_pages_}{\.{\\tracingpages} primitive@>
primitive_tex("tracingoutput",assign_int,int_base+tracing_output_code,int_base);@/
@!@:tracing_output_}{\.{\\tracingoutput} primitive@>
primitive_tex("tracinglostchars",assign_int,int_base+tracing_lost_chars_code,int_base);@/
@!@:tracing_lost_chars_}{\.{\\tracinglostchars} primitive@>
primitive_tex("tracingcommands",assign_int,int_base+tracing_commands_code,int_base);@/
@!@:tracing_commands_}{\.{\\tracingcommands} primitive@>
primitive_tex("tracingrestores",assign_int,int_base+tracing_restores_code,int_base);@/
@!@:tracing_restores_}{\.{\\tracingrestores} primitive@>
primitive_tex("uchyph",assign_int,int_base+uc_hyph_code,int_base);@/
@!@:uc_hyph_}{\.{\\uchyph} primitive@>
primitive_tex("outputpenalty",assign_int,int_base+output_penalty_code,int_base);@/
@!@:output_penalty_}{\.{\\outputpenalty} primitive@>
primitive_tex("maxdeadcycles",assign_int,int_base+max_dead_cycles_code,int_base);@/
@!@:max_dead_cycles_}{\.{\\maxdeadcycles} primitive@>
primitive_tex("hangafter",assign_int,int_base+hang_after_code,int_base);@/
@!@:hang_after_}{\.{\\hangafter} primitive@>
primitive_tex("floatingpenalty",assign_int,int_base+floating_penalty_code,int_base);@/
@!@:floating_penalty_}{\.{\\floatingpenalty} primitive@>
primitive_tex("globaldefs",assign_int,int_base+global_defs_code,int_base);@/
@!@:global_defs_}{\.{\\globaldefs} primitive@>
primitive_tex("fam",assign_int,int_base+cur_fam_code,int_base);@/
@!@:fam_}{\.{\\fam} primitive@>
primitive_tex("escapechar",assign_int,int_base+escape_char_code,int_base);@/
@!@:escape_char_}{\.{\\escapechar} primitive@>
primitive_tex("defaulthyphenchar",assign_int,int_base+default_hyphen_char_code,int_base);@/
@!@:default_hyphen_char_}{\.{\\defaulthyphenchar} primitive@>
primitive_tex("defaultskewchar",assign_int,int_base+default_skew_char_code,int_base);@/
@!@:default_skew_char_}{\.{\\defaultskewchar} primitive@>
primitive_tex("endlinechar",assign_int,int_base+end_line_char_code,int_base);@/
@!@:end_line_char_}{\.{\\endlinechar} primitive@>
primitive_tex("newlinechar",assign_int,int_base+new_line_char_code,int_base);@/
@!@:new_line_char_}{\.{\\newlinechar} primitive@>
primitive_tex("language",assign_int,int_base+language_code,int_base);@/
@!@:language_}{\.{\\language} primitive@>
primitive_tex("setlanguage",assign_int,int_base+cur_lang_code,int_base);@/
@!@:cur_lang_}{\.{\\setlanguage} primitive@>
primitive_tex("exhyphenchar",assign_int,int_base+ex_hyphen_char_code,int_base);@/
@!@:ex_hyphen_char_}{\.{\\exhyphenchar} primitive@>
primitive_tex("lefthyphenmin",assign_int,int_base+left_hyphen_min_code,int_base);@/
@!@:left_hyphen_min_}{\.{\\lefthyphenmin} primitive@>
primitive_tex("righthyphenmin",assign_int,int_base+right_hyphen_min_code,int_base);@/
@!@:right_hyphen_min_}{\.{\\righthyphenmin} primitive@>
primitive_tex("holdinginserts",assign_int,int_base+holding_inserts_code,int_base);@/
@!@:holding_inserts_}{\.{\\holdinginserts} primitive@>
primitive_tex("errorcontextlines",assign_int,int_base+error_context_lines_code,int_base);@/
@!@:error_context_lines_}{\.{\\errorcontextlines} primitive@>
primitive_luatex("luastartup",assign_int,int_base+luastartup_id_code,int_base);@/
@!@:luastartup_id_}{\.{\\luastartup} primitive@>
primitive_luatex("nokerns",assign_int,int_base+disable_kern_code,int_base);@/
@!@:disable_kern_}{\.{\\noligkerns} primitive@>
primitive_luatex("noligs",assign_int,int_base+disable_lig_code,int_base);@/
@!@:disable_lig_}{\.{\\noligs} primitive@>
primitive_luatex("catcodetable",assign_int,int_base+cat_code_table_code,int_base);@/
@!@:cat_code_table_}{\.{\\catcodetable} primitive@>
primitive_luatex("outputbox",assign_int,int_base+output_box_code,int_base);@/
@!@:output_box_}{\.{\\outputbox} primitive@>
primitive_pdftex("pdfoutput",assign_int,int_base+pdf_output_code,int_base);@/
@!@:pdf_output_}{\.{\\pdfoutput} primitive@>
primitive_pdftex("pdfcompresslevel",assign_int,int_base+pdf_compress_level_code,int_base);@/
@!@:pdf_compress_level_}{\.{\\pdfcompresslevel} primitive@>
primitive_pdftex("pdfobjcompresslevel",assign_int,int_base+pdf_objcompresslevel_code,int_base);@/
@!@:pdf_objcompresslevel_}{\.{\\pdfobjcompresslevel} primitive@>
primitive_pdftex("pdfdecimaldigits",assign_int,int_base+pdf_decimal_digits_code,int_base);@/
@!@:pdf_decimal_digits_}{\.{\\pdfdecimaldigits} primitive@>
primitive_pdftex("pdfmovechars",assign_int,int_base+pdf_move_chars_code,int_base);@/
@!@:pdf_move_chars_}{\.{\\pdfmovechars} primitive@>
primitive_pdftex("pdfimageresolution",assign_int,int_base+pdf_image_resolution_code,int_base);@/
@!@:pdf_image_resolution_}{\.{\\pdfimageresolution} primitive@>
primitive_pdftex("pdfpkresolution",assign_int,int_base+pdf_pk_resolution_code,int_base);@/
@!@:pdf_pk_resolution_}{\.{\\pdfpkresolution} primitive@>
primitive_pdftex("pdfuniqueresname",assign_int,int_base+pdf_unique_resname_code,int_base);@/
@!@:pdf_unique_resname_}{\.{\\pdfuniqueresname} primitive@>
primitive_pdftex("pdfoptionpdfminorversion",assign_int,int_base+pdf_minor_version_code,int_base);@/
@!@:pdf_minor_version_}{\.{\\pdfoptionpdfminorversion} primitive@>
primitive_pdftex("pdfoptionalwaysusepdfpagebox",assign_int,int_base+pdf_option_always_use_pdfpagebox_code,int_base);@/
@!@:pdf_option_always_use_pdfpagebox_}{\.{\\pdfoptionalwaysusepdfpagebox} primitive@>
primitive_pdftex("pdfoptionpdfinclusionerrorlevel",assign_int,int_base+pdf_option_pdf_inclusion_errorlevel_code,int_base);@/
@!@:pdf_option_pdf_inclusion_errorlevel_}{\.{\\pdfoptionpdfinclusionerrorlevel} primitive@>
primitive_pdftex("pdfminorversion",assign_int,int_base+pdf_minor_version_code,int_base);@/
@!@:pdf_minor_version_}{\.{\\pdfminorversion} primitive@>
primitive_pdftex("pdfforcepagebox",assign_int,int_base+pdf_force_pagebox_code,int_base);@/
@!@:pdf_force_pagebox_}{\.{\\pdfforcepagebox} primitive@>
primitive_pdftex("pdfpagebox",assign_int,int_base+pdf_pagebox_code,int_base);@/
@!@:pdf_pagebox_}{\.{\\pdfpagebox} primitive@>
primitive_pdftex("pdfinclusionerrorlevel",assign_int,int_base+pdf_inclusion_errorlevel_code,int_base);@/
@!@:pdf_inclusion_errorlevel_}{\.{\\pdfinclusionerrorlevel} primitive@>
primitive_pdftex("pdfgamma",assign_int,int_base+pdf_gamma_code,int_base);@/
@!@:pdf_gamma_}{\.{\\pdfgamma} primitive@>
primitive_pdftex("pdfimagegamma",assign_int,int_base+pdf_image_gamma_code,int_base);@/
@!@:pdf_image_gamma_}{\.{\\pdfimagegamma} primitive@>
primitive_pdftex("pdfimagehicolor",assign_int,int_base+pdf_image_hicolor_code,int_base);@/
@!@:pdf_image_hicolor_}{\.{\\pdfimagehicolor} primitive@>
primitive_pdftex("pdfimageapplygamma",assign_int,int_base+pdf_image_apply_gamma_code,int_base);@/
@!@:pdf_image_apply_gamma_}{\.{\\pdfimageapplygamma} primitive@>
primitive_pdftex("pdfadjustspacing",assign_int,int_base+pdf_adjust_spacing_code,int_base);@/
@!@:pdf_adjust_spacing_}{\.{\\pdfadjustspacing} primitive@>
primitive_pdftex("pdfprotrudechars",assign_int,int_base+pdf_protrude_chars_code,int_base);@/
@!@:pdf_protrude_chars_}{\.{\\pdfprotrudechars} primitive@>
primitive_pdftex("pdftracingfonts",assign_int,int_base+pdf_tracing_fonts_code,int_base);@/
@!@:pdf_tracing_fonts_}{\.{\\pdftracingfonts} primitive@>
primitive_pdftex("pdfgentounicode",assign_int,int_base+pdf_gen_tounicode_code,int_base);@/
@!@:pdf_gen_tounicode_}{\.{\\pdfgentounicode} primitive@>
primitive_pdftex("pdfdraftmode",assign_int,int_base+pdf_draftmode_code,int_base);@/
@!@:pdf_draftmode_}{\.{\\pdfdraftmode} primitive@>
primitive_pdftex("pdfinclusioncopyfonts",assign_int,int_base+pdf_inclusion_copy_font_code,int_base);@/
@!@:pdf_inclusion_copy_font_}{\.{\\pdfinclusioncopyfonts} primitive@>
primitive_pdftex("pdfreplacefont",assign_int,int_base+pdf_replace_font_code,int_base);@/
@!@:pdf_replace_font_}{\.{\\pdfreplacefont} primitive@>

@ The integer parameters should really be initialized by a macro package;
the following initialization does the minimum to keep \TeX\ from
complete failure.
@^null delimiter@>

@<Initialize table entries...@>=
for k:=int_base to attribute_base-1 do eqtb[k].int:=0;
for k:=attribute_base to del_code_base-1 do eqtb[k].int:=UNUSED_ATTRIBUTE;
mag:=1000; tolerance:=10000; hang_after:=1; max_dead_cycles:=25;
escape_char:="\"; end_line_char:=carriage_return;
eqtb[int_base+level_local_dir_code].int:=level_one;
set_del_code(".",tex_mathcode,0,0,0,0,level_one); {this null delimiter is used in error recovery}
ex_hyphen_char:="-";
output_box:=255;

@ The following procedure, which is called just before \TeX\ initializes its
input and output, establishes the initial values of the date and time.
@^system dependencies@>
Since standard \PASCAL\ cannot provide such information, something special
is needed. The program here simply specifies July 4, 1776, at noon; but
users probably want a better approximation to the truth.

@p procedure fix_date_and_time;
begin time:=12*60; {minutes since midnight}
day:=4; {fourth day of the month}
month:=7; {seventh month of the year}
year:=1776; {Anno Domini}
end;

@ @<Show equivalent |n|, in region 5@>=
begin if n<count_base then begin print_param(n-int_base);
    print_char("="); print_int(eqtb[n].int);
  end
else if n<attribute_base then
  begin print_esc("count"); print_int(n-count_base);
    print_char("="); print_int(eqtb[n].int);
  end
else if n<del_code_base then
  begin print_esc("attribute"); print_int(n-attribute_base);
    print_char("="); print_int(eqtb[n].int);
  end;
end

@ @<Set variable |c| to the current escape character@>=c:=escape_char

@ @<Character |s| is the current new-line character@>=s=new_line_char

@ \TeX\ is occasionally supposed to print diagnostic information that
goes only into the transcript file, unless |tracing_online| is positive.
Here are two routines that adjust the destination of print commands:

@p procedure begin_diagnostic; {prepare to do some tracing}
begin global_old_setting:=selector;
if (tracing_online<=0)and(selector=term_and_log) then
  begin decr(selector);
  if history=spotless then history:=warning_issued;
  end;
end;
@#
procedure end_diagnostic(@!blank_line:boolean);
  {restore proper conditions after tracing}
begin print_nl("");
if blank_line then print_ln;
selector:=global_old_setting;
end;

@ Of course we had better declare another global variable, if the previous
routines are going to work.

@<Glob...@>=
@!global_old_setting:0..max_selector;

@ The final region of |eqtb| contains the dimension parameters defined
here, and the |number_regs| \.{\\dimen} registers.

@d par_indent_code=0 {indentation of paragraphs}
@d math_surround_code=1 {space around math in text}
@d line_skip_limit_code=2 {threshold for |line_skip| instead of |baseline_skip|}
@d hsize_code=3 {line width in horizontal mode}
@d vsize_code=4 {page height in vertical mode}
@d max_depth_code=5 {maximum depth of boxes on main pages}
@d split_max_depth_code=6 {maximum depth of boxes on split pages}
@d box_max_depth_code=7 {maximum depth of explicit vboxes}
@d hfuzz_code=8 {tolerance for overfull hbox messages}
@d vfuzz_code=9 {tolerance for overfull vbox messages}
@d delimiter_shortfall_code=10 {maximum amount uncovered by variable delimiters}
@d null_delimiter_space_code=11 {blank space in null delimiters}
@d script_space_code=12 {extra space after subscript or superscript}
@d pre_display_size_code=13 {length of text preceding a display}
@d display_width_code=14 {length of line for displayed equation}
@d display_indent_code=15 {indentation of line for displayed equation}
@d overfull_rule_code=16 {width of rule that identifies overfull hboxes}
@d hang_indent_code=17 {amount of hanging indentation}
@d h_offset_code=18 {amount of horizontal offset when shipping pages out}
@d v_offset_code=19 {amount of vertical offset when shipping pages out}
@d emergency_stretch_code=20 {reduces badnesses on final pass of line-breaking}
@d page_left_offset_code=21
@d page_top_offset_code=22
@d page_right_offset_code=23
@d page_bottom_offset_code=24
@d pdftex_first_dimen_code = 25 {first number defined in this section}
@d pdf_h_origin_code       = pdftex_first_dimen_code + 0 {horigin of the PDF output}
@d pdf_v_origin_code       = pdftex_first_dimen_code + 1 {vorigin of the PDF output}
@d page_width_code         = pdftex_first_dimen_code + 2 {page width of the PDF output}
@d page_height_code        = pdftex_first_dimen_code + 3 {page height of the PDF output}
@d pdf_link_margin_code    = pdftex_first_dimen_code + 4 {link margin in the PDF output}
@d pdf_dest_margin_code    = pdftex_first_dimen_code + 5 {dest margin in the PDF output}
@d pdf_thread_margin_code  = pdftex_first_dimen_code + 6 {thread margin in the PDF output}
@d pdf_first_line_height_code = pdftex_first_dimen_code + 7
@d pdf_last_line_depth_code   = pdftex_first_dimen_code + 8
@d pdf_each_line_height_code  = pdftex_first_dimen_code + 9
@d pdf_each_line_depth_code   = pdftex_first_dimen_code + 10
@d pdf_ignored_dimen_code   = pdftex_first_dimen_code + 11
@d pdf_px_dimen_code       = pdftex_first_dimen_code + 12
@d pdftex_last_dimen_code  = pdftex_first_dimen_code + 12 {last number defined in this section}
@d dimen_pars = pdftex_last_dimen_code + 1 {total number of dimension parameters}
@d scaled_base=dimen_base+dimen_pars
  {table of |number_regs| user-defined \.{\\dimen} registers}
@d eqtb_size=scaled_base+biggest_reg {largest subscript of |eqtb|}
@#
@d dimen(#)==eqtb[scaled_base+#].sc
@d dimen_par(#)==eqtb[dimen_base+#].sc {a scaled quantity}
@d par_indent==dimen_par(par_indent_code)
@d math_surround==dimen_par(math_surround_code)
@d line_skip_limit==dimen_par(line_skip_limit_code)
@d hsize==dimen_par(hsize_code)
@d vsize==dimen_par(vsize_code)
@d max_depth==dimen_par(max_depth_code)
@d split_max_depth==dimen_par(split_max_depth_code)
@d box_max_depth==dimen_par(box_max_depth_code)
@d hfuzz==dimen_par(hfuzz_code)
@d vfuzz==dimen_par(vfuzz_code)
@d delimiter_shortfall==dimen_par(delimiter_shortfall_code)
@d null_delimiter_space==dimen_par(null_delimiter_space_code)
@d script_space==dimen_par(script_space_code)
@d pre_display_size==dimen_par(pre_display_size_code)
@d display_width==dimen_par(display_width_code)
@d display_indent==dimen_par(display_indent_code)
@d overfull_rule==dimen_par(overfull_rule_code)
@d hang_indent==dimen_par(hang_indent_code)
@d h_offset==dimen_par(h_offset_code)
@d v_offset==dimen_par(v_offset_code)
@d emergency_stretch==dimen_par(emergency_stretch_code)
@d page_left_offset==dimen_par(page_left_offset_code)
@d page_top_offset==dimen_par(page_top_offset_code)
@d page_right_offset==dimen_par(page_right_offset_code)
@d page_bottom_offset==dimen_par(page_bottom_offset_code)
@d pdf_h_origin      == dimen_par(pdf_h_origin_code)
@d pdf_v_origin      == dimen_par(pdf_v_origin_code)
@d page_width    == dimen_par(page_width_code)
@d page_height   == dimen_par(page_height_code)
@d pdf_link_margin   == dimen_par(pdf_link_margin_code)
@d pdf_dest_margin   == dimen_par(pdf_dest_margin_code)
@d pdf_thread_margin == dimen_par(pdf_thread_margin_code)
@d pdf_first_line_height == dimen_par(pdf_first_line_height_code)
@d pdf_last_line_depth   == dimen_par(pdf_last_line_depth_code)
@d pdf_each_line_height  == dimen_par(pdf_each_line_height_code)
@d pdf_each_line_depth   == dimen_par(pdf_each_line_depth_code)
@d pdf_ignored_dimen     == dimen_par(pdf_ignored_dimen_code)
@d pdf_px_dimen      == dimen_par(pdf_px_dimen_code)

@p procedure print_length_param(@!n:integer);
begin case n of
par_indent_code:print_esc("parindent");
math_surround_code:print_esc("mathsurround");
line_skip_limit_code:print_esc("lineskiplimit");
hsize_code:print_esc("hsize");
vsize_code:print_esc("vsize");
max_depth_code:print_esc("maxdepth");
split_max_depth_code:print_esc("splitmaxdepth");
box_max_depth_code:print_esc("boxmaxdepth");
hfuzz_code:print_esc("hfuzz");
vfuzz_code:print_esc("vfuzz");
delimiter_shortfall_code:print_esc("delimitershortfall");
null_delimiter_space_code:print_esc("nulldelimiterspace");
script_space_code:print_esc("scriptspace");
pre_display_size_code:print_esc("predisplaysize");
display_width_code:print_esc("displaywidth");
display_indent_code:print_esc("displayindent");
overfull_rule_code:print_esc("overfullrule");
hang_indent_code:print_esc("hangindent");
h_offset_code:print_esc("hoffset");
v_offset_code:print_esc("voffset");
emergency_stretch_code:print_esc("emergencystretch");
page_left_offset_code:  print_esc("pageleftoffset");
page_top_offset_code:   print_esc("pagetopoffset");
page_right_offset_code: print_esc("pagerightoffset");
page_bottom_offset_code:print_esc("pagebottomoffset");
pdf_h_origin_code:      print_esc("pdfhorigin");
pdf_v_origin_code:      print_esc("pdfvorigin");
page_width_code:    print_esc("pagewidth");
page_height_code:   print_esc("pageheight");
pdf_link_margin_code:   print_esc("pdflinkmargin");
pdf_dest_margin_code:   print_esc("pdfdestmargin");
pdf_thread_margin_code: print_esc("pdfthreadmargin");
pdf_first_line_height_code: print_esc("pdffirstlineheight");
pdf_last_line_depth_code: print_esc("pdflastlinedepth");
pdf_each_line_height_code: print_esc("pdfeachlineheight");
pdf_each_line_depth_code: print_esc("pdfeachlinedepth");
pdf_ignored_dimen_code: print_esc("pdfignoreddimen");
pdf_px_dimen_code:      print_esc("pdfpxdimen");
othercases print("[unknown dimen parameter!]")
endcases;
end;

@ @<Put each...@>=
primitive_tex("parindent",assign_dimen,dimen_base+par_indent_code,dimen_base);@/
@!@:par_indent_}{\.{\\parindent} primitive@>
primitive_tex("mathsurround",assign_dimen,dimen_base+math_surround_code,dimen_base);@/
@!@:math_surround_}{\.{\\mathsurround} primitive@>
primitive_tex("lineskiplimit",assign_dimen,dimen_base+line_skip_limit_code,dimen_base);@/
@!@:line_skip_limit_}{\.{\\lineskiplimit} primitive@>
primitive_tex("hsize",assign_dimen,dimen_base+hsize_code,dimen_base);@/
@!@:hsize_}{\.{\\hsize} primitive@>
primitive_tex("vsize",assign_dimen,dimen_base+vsize_code,dimen_base);@/
@!@:vsize_}{\.{\\vsize} primitive@>
primitive_tex("maxdepth",assign_dimen,dimen_base+max_depth_code,dimen_base);@/
@!@:max_depth_}{\.{\\maxdepth} primitive@>
primitive_tex("splitmaxdepth",assign_dimen,dimen_base+split_max_depth_code,dimen_base);@/
@!@:split_max_depth_}{\.{\\splitmaxdepth} primitive@>
primitive_tex("boxmaxdepth",assign_dimen,dimen_base+box_max_depth_code,dimen_base);@/
@!@:box_max_depth_}{\.{\\boxmaxdepth} primitive@>
primitive_tex("hfuzz",assign_dimen,dimen_base+hfuzz_code,dimen_base);@/
@!@:hfuzz_}{\.{\\hfuzz} primitive@>
primitive_tex("vfuzz",assign_dimen,dimen_base+vfuzz_code,dimen_base);@/
@!@:vfuzz_}{\.{\\vfuzz} primitive@>
primitive_tex("delimitershortfall", assign_dimen,dimen_base+delimiter_shortfall_code,dimen_base);@/
@!@:delimiter_shortfall_}{\.{\\delimitershortfall} primitive@>
primitive_tex("nulldelimiterspace", assign_dimen,dimen_base+null_delimiter_space_code,dimen_base);@/
@!@:null_delimiter_space_}{\.{\\nulldelimiterspace} primitive@>
primitive_tex("scriptspace",assign_dimen,dimen_base+script_space_code,dimen_base);@/
@!@:script_space_}{\.{\\scriptspace} primitive@>
primitive_tex("predisplaysize",assign_dimen,dimen_base+pre_display_size_code,dimen_base);@/
@!@:pre_display_size_}{\.{\\predisplaysize} primitive@>
primitive_tex("displaywidth",assign_dimen,dimen_base+display_width_code,dimen_base);@/
@!@:display_width_}{\.{\\displaywidth} primitive@>
primitive_tex("displayindent",assign_dimen,dimen_base+display_indent_code,dimen_base);@/
@!@:display_indent_}{\.{\\displayindent} primitive@>
primitive_tex("overfullrule",assign_dimen,dimen_base+overfull_rule_code,dimen_base);@/
@!@:overfull_rule_}{\.{\\overfullrule} primitive@>
primitive_tex("hangindent",assign_dimen,dimen_base+hang_indent_code,dimen_base);@/
@!@:hang_indent_}{\.{\\hangindent} primitive@>
primitive_tex("hoffset",assign_dimen,dimen_base+h_offset_code,dimen_base);@/
@!@:h_offset_}{\.{\\hoffset} primitive@>
primitive_tex("voffset",assign_dimen,dimen_base+v_offset_code,dimen_base);@/
@!@:v_offset_}{\.{\\voffset} primitive@>
primitive_tex("emergencystretch",assign_dimen,dimen_base+emergency_stretch_code,dimen_base);@/
@!@:emergency_stretch_}{\.{\\emergencystretch} primitive@>
primitive_pdftex("pdfhorigin",assign_dimen,dimen_base+pdf_h_origin_code,dimen_base);@/
@!@:pdf_h_origin_}{\.{\\pdfhorigin} primitive@>
primitive_pdftex("pdfvorigin",assign_dimen,dimen_base+pdf_v_origin_code,dimen_base);@/
@!@:pdf_v_origin_}{\.{\\pdfvorigin} primitive@>
@#
primitive_omega("pagewidth",assign_dimen,dimen_base+page_width_code,dimen_base);@/
primitive_pdftex("pdfpagewidth",assign_dimen,dimen_base+page_width_code,dimen_base);@/
@!@:page_width_}{\.{\\pdfpagewidth} primitive@>
primitive_omega("pageheight",assign_dimen,dimen_base+page_height_code,dimen_base);@/
primitive_pdftex("pdfpageheight",assign_dimen,dimen_base+page_height_code,dimen_base);@/
@!@:page_height_}{\.{\\pdfpageheight} primitive@>
@#
primitive_pdftex("pdflinkmargin",assign_dimen,dimen_base+pdf_link_margin_code,dimen_base);@/
@!@:pdf_link_margin_}{\.{\\pdflinkmargin} primitive@>
primitive_pdftex("pdfdestmargin",assign_dimen,dimen_base+pdf_dest_margin_code,dimen_base);@/
@!@:pdf_dest_margin_}{\.{\\pdfdestmargin} primitive@>
primitive_pdftex("pdfthreadmargin",assign_dimen,dimen_base+pdf_thread_margin_code,dimen_base);@/
@!@:pdf_thread_margin_}{\.{\\pdfthreadmargin} primitive@>
primitive_pdftex("pdffirstlineheight",assign_dimen,dimen_base+pdf_first_line_height_code,dimen_base);@/
@!@:pdf_first_line_height_}{\.{\\pdffirstlineheight} primitive@>
primitive_pdftex("pdflastlinedepth",assign_dimen,dimen_base+pdf_last_line_depth_code,dimen_base);@/
@!@:pdf_last_line_depth_}{\.{\\pdflastlinedepth} primitive@>
primitive_pdftex("pdfeachlineheight",assign_dimen,dimen_base+pdf_each_line_height_code,dimen_base);@/
@!@:pdf_each_line_height_}{\.{\\pdfeachlineheight} primitive@>
primitive_pdftex("pdfeachlinedepth",assign_dimen,dimen_base+pdf_each_line_depth_code,dimen_base);@/
@!@:pdf_each_line_depth_}{\.{\\pdfeachlinedepth} primitive@>
primitive_pdftex("pdfignoreddimen",assign_dimen,dimen_base+pdf_ignored_dimen_code,dimen_base);@/
@!@:pdf_ignored_dimen_}{\.{\\pdfignoreddimen} primitive@>
primitive_pdftex("pdfpxdimen",assign_dimen,dimen_base+pdf_px_dimen_code,dimen_base);@/
@!@:pdf_px_dimen_}{\.{\\pdfpxdimen} primitive@>

@ @<Initialize table entries...@>=
for k:=dimen_base to eqtb_size do eqtb[k].sc:=0;
page_left_offset := one_inch;
page_top_offset := one_inch;
page_right_offset := one_inch;
page_bottom_offset := one_inch;

@ @<Initialize table entries...@>=
pdf_ignored_dimen := ignore_depth;
pdf_each_line_height := pdf_ignored_dimen;
pdf_each_line_depth := pdf_ignored_dimen;
pdf_first_line_height := pdf_ignored_dimen;
pdf_last_line_depth := pdf_ignored_dimen;


@ @<Show equivalent |n|, in region 6@>=
begin if n<scaled_base then print_length_param(n-dimen_base)
else  begin print_esc("dimen"); print_int(n-scaled_base);
  end;
print_char("="); print_scaled(eqtb[n].sc); print("pt");
end

@ Here is a procedure that displays the contents of |eqtb[n]|
symbolically.

@p
@!stat procedure show_eqtb(@!n:pointer);
begin if n<null_cs then print_char("?") {this can't happen}
else if n<glue_base then @<Show equivalent |n|, in region 1 or 2@>
else if n<local_base then @<Show equivalent |n|, in region 3@>
else if n<int_base then @<Show equivalent |n|, in region 4@>
else if n<dimen_base then @<Show equivalent |n|, in region 5@>
else if n<=eqtb_size then @<Show equivalent |n|, in region 6@>
else print_char("?"); {this can't happen either}
end;
tats

@ The last two regions of |eqtb| have fullword values instead of the
three fields |eq_level|, |eq_type|, and |equiv|. An |eq_type| is unnecessary,
but \TeX\ needs to store the |eq_level| information in another array
called |xeq_level|.

@<Glob...@>=
@!eqtb:array[null_cs..eqtb_size] of memory_word;
@!xeq_level:array[null_cs..eqtb_size] of quarterword;

@ @<Set init...@>=
for k:=int_base to eqtb_size do xeq_level[k]:=level_one;

@* \[18] The hash table.
Control sequences are stored and retrieved by means of a fairly standard hash
table algorithm called the method of ``coalescing lists'' (cf.\ Algorithm 6.4C
in {\sl The Art of Computer Programming\/}). Once a control sequence enters the
table, it is never removed, because there are complicated situations
involving \.{\\gdef} where the removal of a control sequence at the end of
a group would be a mistake preventable only by the introduction of a
complicated reference-count mechanism.

The actual sequence of letters forming a control sequence identifier is
stored in the |str_pool| array together with all the other strings. An
auxiliary array |hash| consists of items with two halfword fields per
word. The first of these, called |next(p)|, points to the next identifier
belonging to the same coalesced list as the identifier corresponding to~|p|;
and the other, called |text(p)|, points to the |str_start| entry for
|p|'s identifier. If position~|p| of the hash table is empty, we have
|text(p)=0|; if position |p| is either empty or the end of a coalesced
hash list, we have |next(p)=0|. An auxiliary pointer variable called
|hash_used| is maintained in such a way that all locations |p>=hash_used|
are nonempty. The global variable |cs_count| tells how many multiletter
control sequences have been defined, if statistics are being kept.

A global boolean variable called |no_new_control_sequence| is set to
|true| during the time that new hash table entries are forbidden.

@d next(#) == hash[#].lh {link for coalesced lists}
@d text(#) == hash[#].rh {string number for control sequence name}
@d hash_is_full == (hash_used=hash_base) {test if all positions are occupied}
@d font_id_text(#) == text(font_id_base+#) {a frozen font identifier's name}
@d ocp_id_text(#) == text(ocp_id_base+#) {a frozen ocp identifier's name}
@d ocp_list_id_text(#) == text(ocp_list_id_base+#)
   {a frozen ocp list identifier's name}

@<Glob...@>=
@!hash: array[hash_base..undefined_control_sequence-1] of two_halves;
  {the hash table}
@!hash_used:pointer; {allocation pointer for |hash|}
@!no_new_control_sequence:boolean; {are new identifiers legal?}
@!cs_count:integer; {total number of known identifiers}

@ The extra set of functions make sure we can query the
primitive meanings of thing s from C code

@p
function get_eq_type(p:integer):quarterword;
begin
  get_eq_type := eq_type(p);
end;
function get_eq_level(p:integer):quarterword;
begin
  get_eq_level := eq_level(p);
end;
function is_undefined_cs(cs:integer):boolean;
begin
  is_undefined_cs := (cs=undefined_cs);
end;
function get_equiv(p:integer):halfword;
begin
  get_equiv := equiv(p);
end;
function get_cs_text(cs:integer):str_number;
begin if cs=null_cs then get_cs_text := "\csname\endcsname"
  else if (text(cs)<0)or(text(cs)>=str_ptr) then get_cs_text := ""
  else get_cs_text := text(cs);
end;
function get_max_command:integer;
begin
  get_max_command := max_command;
end;
function get_count_base:halfword;
begin
  get_count_base := count_base;
end;
function get_skip_base:halfword;
begin
  get_skip_base := skip_base;
end;
function get_mu_skip_base:halfword;
begin
  get_mu_skip_base := mu_skip_base;
end;
function get_attribute_base:halfword;
begin
  get_attribute_base := attribute_base;
end;
function get_scaled_base:halfword;
begin
  get_scaled_base := scaled_base;
end;
function get_int_base:halfword;
begin
  get_int_base := int_base;
end;
function get_dimen_base:halfword;
begin
  get_dimen_base := dimen_base;
end;
function get_toks_base:halfword;
begin
  get_toks_base := toks_base;
end;
function get_del_code_base:halfword;
begin
  get_del_code_base := del_code_base;
end;
function get_every_eof:halfword;
begin
  get_every_eof := every_eof;
end;
function get_suppress_fontnotfound_error:boolean;
begin
  get_suppress_fontnotfound_error := suppress_fontnotfound_error;
end;
function get_pdf_image_resolution:integer;
begin
  get_pdf_image_resolution := pdf_image_resolution;
end;
function get_pdf_minor_version:integer;
begin
  get_pdf_minor_version := pdf_minor_version;
end;
function get_pdf_inclusion_errorlevel:integer;
begin
  get_pdf_inclusion_errorlevel := pdf_inclusion_errorlevel;
end;

@ @<Set init...@>=
no_new_control_sequence:=true; {new identifiers are usually forbidden}
init_primitives;
next(hash_base):=0; text(hash_base):=0;
for k:=hash_base+1 to undefined_control_sequence-1 do hash[k]:=hash[hash_base];

@ @<Initialize table entries...@>=
ini_init_primitives;
hash_used:=frozen_control_sequence; {nothing is used}
cs_count:=0;
eq_type(frozen_dont_expand):=dont_expand;
text(frozen_dont_expand):="notexpanded:";
@.notexpanded:@>

eq_type(frozen_primitive):=ignore_spaces;
equiv(frozen_primitive):=1;
eq_level(frozen_primitive):=level_one;
text(frozen_primitive):="primitive";


@ The procedure |print_cs| prints the name of a control sequence, given
a pointer to its address in |eqtb|. A space is printed after the name
unless it is a single nonletter or an active character. This procedure
might be invoked with invalid data, so it is ``extra robust.'' The
individual characters must be printed one at a time using |print|, since
they may be unprintable.

@d single_letter(#)==(length(#)=1)or
   ((length(#)=4)and(str_pool[str_start_macro(#)]>=@"F0))or
   ((length(#)=3)and(str_pool[str_start_macro(#)]>=@"E0))or
   ((length(#)=2)and(str_pool[str_start_macro(#)]>=@"C0))

@d is_active_csname(#)==((length(text(#))>3)and
  (str_pool[str_start_macro(text(#))]=@"EF)and
  (str_pool[str_start_macro(text(#))+1]=@"BF)and
  (str_pool[str_start_macro(text(#))+2]=@"BF))

@d active_csname_value(#)==pool_to_unichar(str_start_macro(text(#))+3)

@<Basic printing...@>=
procedure print_cs(@!p:integer); {prints a purported control sequence}
begin if p<hash_base then { nullcs}
  if p=null_cs then
    begin print_esc("csname"); print_esc("endcsname");
    end
  else print_esc("IMPOSSIBLE.")
@.IMPOSSIBLE@>
else if p>=undefined_control_sequence then print_esc("IMPOSSIBLE.")
else if (text(p)<0)or(text(p)>=str_ptr) then print_esc("NONEXISTENT.")
@.NONEXISTENT@>
else begin
  if is_active_csname(p) then
    print(active_csname_value(p))
  else begin
    print_esc(text(p));
    if single_letter(text(p)) then begin
       if get_cat_code(cat_code_table,pool_to_unichar(str_start_macro(text(p))))=letter then
         print_char(" ")
       else
         do_nothing;
       end
    else
      print_char(" ");
    end
  end;
end;

@ Here is a similar procedure; it avoids the error checks, and it never
prints a space after the control sequence.

@<Basic printing procedures@>=
procedure sprint_cs(@!p:pointer); {prints a control sequence}
begin if p=null_cs then begin
  print_esc("csname"); print_esc("endcsname");
  end
else begin
  if is_active_csname(p) then
    print(active_csname_value(p))
  else
    print_esc(text(p));
  end;
end;


@ Many of \TeX's primitives need no |equiv|, since they are identifiable
by their |eq_type| alone. These primitives are loaded into the hash table
as follows:

@<Put each of \TeX's primitives into the hash table@>=
primitive_tex(" ",ex_space,0,0);@/
@!@:Single-character primitives /}{\quad\.{\\\ }@>
primitive_tex("/",ital_corr,0,0);@/
@!@:Single-character primitives /}{\quad\.{\\/}@>
primitive_tex("accent",accent,0,0);@/
@!@:accent_}{\.{\\accent} primitive@>
primitive_tex("advance",advance,0,0);@/
@!@:advance_}{\.{\\advance} primitive@>
primitive_tex("afterassignment",after_assignment,0,0);@/
@!@:after_assignment_}{\.{\\afterassignment} primitive@>
primitive_tex("aftergroup",after_group,0,0);@/
@!@:after_group_}{\.{\\aftergroup} primitive@>
primitive_tex("begingroup",begin_group,0,0);@/
@!@:begin_group_}{\.{\\begingroup} primitive@>
primitive_tex("char",char_num,0,0);@/
@!@:char_}{\.{\\char} primitive@>
primitive_tex("csname",cs_name,0,0);@/
@!@:cs_name_}{\.{\\csname} primitive@>
primitive_tex("delimiter",delim_num,0,0);@/
@!@:delimiter_}{\.{\\delimiter} primitive@>
primitive_omega("odelimiter",delim_num,1,0);@/
@!@:odelimiter_}{\.{\\odelimiter} primitive@>
primitive_luatex("Udelimiter",delim_num,2,0);@/
@!@:odelimiter_}{\.{\\Udelimiter} primitive@>
primitive_tex("divide",divide,0,0);@/
@!@:divide_}{\.{\\divide} primitive@>
primitive_tex("endcsname",end_cs_name,0,0);@/
@!@:end_cs_name_}{\.{\\endcsname} primitive@>
primitive_tex("endgroup",end_group,0,0);
@!@:end_group_}{\.{\\endgroup} primitive@>
text(frozen_end_group):="endgroup"; eqtb[frozen_end_group]:=eqtb[cur_val];@/
primitive_tex("expandafter",expand_after,0,0);@/
@!@:expand_after_}{\.{\\expandafter} primitive@>
primitive_tex("font",def_font,0,0);@/
@!@:font_}{\.{\\font} primitive@>
primitive_pdftex("letterspacefont",letterspace_font,0,0);@/
@!@:letterspace_font_}{\.{\\letterspacefont} primitive@>
primitive_pdftex("pdfcopyfont",pdf_copy_font,0,0);@/
@!@:pdf_copy_font_}{\.{\\pdfcopyfont} primitive@>
primitive_tex("fontdimen",assign_font_dimen,0,0);@/
@!@:font_dimen_}{\.{\\fontdimen} primitive@>
primitive_tex("halign",halign,0,0);@/
@!@:halign_}{\.{\\halign} primitive@>
primitive_tex("hrule",hrule,0,0);@/
@!@:hrule_}{\.{\\hrule} primitive@>
primitive_tex("ignorespaces",ignore_spaces,0,0);@/
@!@:ignore_spaces_}{\.{\\ignorespaces} primitive@>
primitive_tex("insert",insert,0,0);@/
@!@:insert_}{\.{\\insert} primitive@>
primitive_omega("leftghost",char_ghost,0,0);@/
@!@:leftghost_}{\.{\\leftghost} primitive@>
primitive_tex("mark",mark,0,0);@/
@!@:mark_}{\.{\\mark} primitive@>
primitive_tex("mathaccent",math_accent,0,0);@/
@!@:math_accent_}{\.{\\mathaccent} primitive@>
primitive_omega("omathaccent",math_accent,1,0);@/
@!@:math_accent_}{\.{\\omathaccent} primitive@>
primitive_luatex("Umathaccent",math_accent,2,0);@/
@!@:math_accent_}{\.{\\Umathaccent} primitive@>
primitive_luatex("Umathbotaccent",math_accent,3,0);@/
@!@:math_accent_}{\.{\\Umathbotaccent} primitive@>
primitive_luatex("Umathaccents",math_accent,4,0);@/
@!@:math_accent_}{\.{\\Umathaccents} primitive@>
primitive_tex("mathchar",math_char_num,0,0);@/
@!@:math_char_}{\.{\\mathchar} primitive@>
primitive_omega("omathchar",math_char_num,1,0);@/
@!@:math_char_}{\.{\\omathchar} primitive@>
primitive_luatex("Umathchar",math_char_num,2,0);@/
@!@:math_char_}{\.{\\Umathchar} primitive@>
primitive_luatex("Umathcharnum",math_char_num,3,0);@/
@!@:math_char_}{\.{\\Umathcharnum} primitive@>
primitive_tex("mathchoice",math_choice,0,0);@/
@!@:math_choice_}{\.{\\mathchoice} primitive@>
primitive_luatex("Ustack",math_choice,1,0);@/
@!@:math_choice_}{\.{\\Ustack} primitive@>
primitive_tex("multiply",multiply,0,0);@/
@!@:multiply_}{\.{\\multiply} primitive@>
primitive_tex("noalign",no_align,0,0);@/
@!@:no_align_}{\.{\\noalign} primitive@>
primitive_tex("noboundary",no_boundary,0,0);@/
@!@:no_boundary_}{\.{\\noboundary} primitive@>
primitive_tex("noexpand",no_expand,0,0);@/
@!@:no_expand_}{\.{\\noexpand} primitive@>
primitive_luatex("primitive",no_expand,1,0);@/
@!@:primitive_}{\.{\\primitive} primitive@>
primitive_pdftex("pdfprimitive",no_expand,1,0);@/
@!@:pdfprimitive_}{\.{\\pdfprimitive} primitive@>
primitive_tex("nonscript",non_script,0,0);@/
@!@:non_script_}{\.{\\nonscript} primitive@>
primitive_tex("omit",omit,0,0);@/
@!@:omit_}{\.{\\omit} primitive@>
primitive_tex("parshape",set_tex_shape,par_shape_loc,par_shape_loc);@/
@!@:par_shape_}{\.{\\parshape} primitive@>
primitive_tex("penalty",break_penalty,0,0);@/
@!@:penalty_}{\.{\\penalty} primitive@>
primitive_tex("prevgraf",set_prev_graf,0,0);@/
@!@:prev_graf_}{\.{\\prevgraf} primitive@>
primitive_tex("radical",radical,0,0);@/
@!@:radical_}{\.{\\radical} primitive@>
primitive_omega("oradical",radical,1,0);@/
@!@:radical_}{\.{\\oradical} primitive@>
primitive_luatex("Uradical",radical,2,0);@/
@!@:radical_}{\.{\\Uradical} primitive@>
primitive_luatex("Uroot",radical,3,0);@/
@!@:radical_}{\.{\\Uroot} primitive@>
primitive_luatex("Uunderdelimiter",radical,4,0);@/
@!@:radical_}{\.{\\Uunderdelimiter} primitive@>
primitive_luatex("Uoverdelimiter",radical,5,0);@/
@!@:radical_}{\.{\\Uoverdelimiter} primitive@>
primitive_luatex("Udelimiterunder",radical,6,0);@/
@!@:radical_}{\.{\\Udelimiterunder} primitive@>
primitive_luatex("Udelimiterover",radical,7,0);@/
@!@:radical_}{\.{\\Udelimiterover} primitive@>
primitive_tex("read",read_to_cs,0,0);@/
@!@:read_}{\.{\\read} primitive@>
primitive_tex("relax",relax,too_big_char,too_big_char);
@!@:relax_}{\.{\\relax} primitive@>
text(frozen_relax):="relax"; eqtb[frozen_relax]:=eqtb[cur_val];@/
primitive_omega("rightghost",char_ghost,1,0);@/
@!@:rightghost_}{\.{\\rightghost} primitive@>
primitive_tex("setbox",set_box,0,0);@/
@!@:set_box_}{\.{\\setbox} primitive@>
primitive_tex("the",the,0,0);@/
@!@:the_}{\.{\\the} primitive@>
primitive_tex("toks",toks_register,0,0);@/
@!@:toks_}{\.{\\toks} primitive@>
primitive_tex("vadjust",vadjust,0,0);@/
@!@:vadjust_}{\.{\\vadjust} primitive@>
primitive_tex("valign",valign,0,0);@/
@!@:valign_}{\.{\\valign} primitive@>
primitive_tex("vcenter",vcenter,0,0);@/
@!@:vcenter_}{\.{\\vcenter} primitive@>
primitive_tex("vrule",vrule,0,0);@/
@!@:vrule_}{\.{\\vrule} primitive@>

@ Each primitive has a corresponding inverse, so that it is possible to
display the cryptic numeric contents of |eqtb| in symbolic form.
Every call of |primitive| in this program is therefore accompanied by some
straightforward code that forms part of the |print_cmd_chr| routine
below.

@ We will deal with the other primitives later, at some point in the program
where their |eq_type| and |equiv| values are more meaningful.  For example,
the primitives for math mode will be loaded when we consider the routines
that deal with formulas. It is easy to find where each particular
primitive was treated by looking in the index at the end; for example, the
section where |"radical"| entered |eqtb| is listed under `\.{\\radical}
primitive'. (Primitives consisting of a single nonalphabetic character,
@!like `\.{\\/}', are listed under `Single-character primitives'.)
@!@^Single-character primitives@>


@* \[19] Saving and restoring equivalents.
The nested structure provided by `$\.{\char'173}\ldots\.{\char'175}$' groups
in \TeX\ means that |eqtb| entries valid in outer groups should be saved
and restored later if they are overridden inside the braces. When a new |eqtb|
value is being assigned, the program therefore checks to see if the previous
entry belongs to an outer level. In such a case, the old value is placed
on the |save_stack| just before the new value enters |eqtb|. At the
end of a grouping level, i.e., when the right brace is sensed, the
|save_stack| is used to restore the outer values, and the inner ones are
destroyed.

Entries on the |save_stack| are of type |memory_word|. The top item on
this stack is |save_stack[p]|, where |p=save_ptr-1|; it contains three
fields called |save_type|, |save_level|, and |save_index|, and it is
interpreted in one of four ways:

\yskip\hangg 1) If |save_type(p)=restore_old_value|, then
|save_index(p)| is a location in |eqtb| whose current value should
be destroyed at the end of the current group and replaced by |save_stack[p-1]|.
Furthermore if |save_index(p)>=int_base|, then |save_level(p)|
should replace the corresponding entry in |xeq_level|.

\yskip\hangg 2) If |save_type(p)=restore_zero|, then |save_index(p)|
is a location in |eqtb| whose current value should be destroyed at the end
of the current group, when it should be
replaced by the current value of |eqtb[undefined_control_sequence]|.

\yskip\hangg 3) If |save_type(p)=insert_token|, then |save_index(p)|
is a token that should be inserted into \TeX's input when the current
group ends.

\yskip\hangg 4) If |save_type(p)=level_boundary|, then |save_level(p)|
is a code explaining what kind of group we were previously in, and
|save_index(p)| points to the level boundary word at the bottom of
the entries for that group.
Furthermore, in extended \eTeX\ mode, |save_stack[p-1]| contains the
source line number at which the current level of grouping was entered.

@d save_type(#)==save_stack[#].hh.b0 {classifies a |save_stack| entry}
@d save_level(#)==save_stack[#].hh.b1
  {saved level for regions 5 and 6, or group code}
@d save_index(#)==save_stack[#].hh.rh
  {|eqtb| location or token or |save_stack| location}
@d restore_old_value=0 {|save_type| when a value should be restored later}
@d restore_zero=1 {|save_type| when an undefined entry should be restored}
@d insert_token=2 {|save_type| when a token is being saved for later use}
@d level_boundary=3 {|save_type| corresponding to beginning of group}

@p@t\4@>@<Declare \eTeX\ procedures for tracing and input@>

@ Here are the group codes that are used to discriminate between different
kinds of groups. They allow \TeX\ to decide what special actions, if any,
should be performed when a group ends.
\def\grp{\.{\char'173...\char'175}}

Some groups are not supposed to be ended by right braces. For example,
the `\.\$' that begins a math formula causes a |math_shift_group| to
be started, and this should be terminated by a matching `\.\$'. Similarly,
a group that starts with \.{\\left} should end with \.{\\right}, and
one that starts with \.{\\begingroup} should end with \.{\\endgroup}.

@d bottom_level=0 {group code for the outside world}
@d simple_group=1 {group code for local structure only}
@d hbox_group=2 {code for `\.{\\hbox}\grp'}
@d adjusted_hbox_group=3 {code for `\.{\\hbox}\grp' in vertical mode}
@d vbox_group=4 {code for `\.{\\vbox}\grp'}
@d vtop_group=5 {code for `\.{\\vtop}\grp'}
@d align_group=6 {code for `\.{\\halign}\grp', `\.{\\valign}\grp'}
@d no_align_group=7 {code for `\.{\\noalign}\grp'}
@d output_group=8 {code for output routine}
@d math_group=9 {code for, e.g., `\.{\char'136}\grp'}
@d disc_group=10 {code for `\.{\\discretionary}\grp\grp\grp'}
@d insert_group=11 {code for `\.{\\insert}\grp', `\.{\\vadjust}\grp'}
@d vcenter_group=12 {code for `\.{\\vcenter}\grp'}
@d math_choice_group=13 {code for `\.{\\mathchoice}\grp\grp\grp\grp'}
@d semi_simple_group=14 {code for `\.{\\begingroup...\\endgroup}'}
@d math_shift_group=15 {code for `\.{\$...\$}'}
@d math_left_group=16 {code for `\.{\\left...\\right}'}
@d local_box_group=17 {code for `\.{\\localleftbox...\\localrightbox}'}
@d max_group_code=17
@d split_off_group=18 {box code for the top part of a \.{\\vsplit}}
@d split_keep_group=19 {box code for the bottom part of a \.{\\vsplit}}
@d preamble_group=20 {box code for the preamble processing  in an alignment}
@d align_set_group=21 {box code for the final item pass in an alignment}
@d fin_row_group=22 {box code for a provisory line in an alignment}

@<Types...@>=
@!group_code=0..max_group_code; {|save_level| for a level boundary}

@ The global variable |cur_group| keeps track of what sort of group we are
currently in. Another global variable, |cur_boundary|, points to the
topmost |level_boundary| word.  And |cur_level| is the current depth of
nesting. The routines are designed to preserve the condition that no entry
in the |save_stack| or in |eqtb| ever has a level greater than |cur_level|.

@ @<Glob...@>=
@!save_stack : array[0..save_size] of memory_word;
@!save_ptr : 0..save_size; {first unused entry on |save_stack|}
@!max_save_stack:0..save_size; {maximum usage of save stack}
@!cur_level: quarterword; {current nesting level for groups}
@!cur_group: group_code; {current group type}
@!cur_boundary: 0..save_size; {where the current level begins}

@ At this time it might be a good idea for the reader to review the introduction
to |eqtb| that was given above just before the long lists of parameter names.
Recall that the ``outer level'' of the program is |level_one|, since
undefined control sequences are assumed to be ``defined'' at |level_zero|.

@<Set init...@>=
save_ptr:=0; cur_level:=level_one; cur_group:=bottom_level; cur_boundary:=0;
max_save_stack:=0;

@ The following macro is used to test if there is room for up to eight more
entries on |save_stack|. By making a conservative test like this, we can
get by with testing for overflow in only a few places.

@d check_full_save_stack==if save_ptr>max_save_stack then
  begin max_save_stack:=save_ptr;
  if max_save_stack>save_size-8 then overflow("save size",save_size);
@:TeX capacity exceeded save size}{\quad save size@>
  end

@ Procedure |new_save_level| is called when a group begins. The
argument is a group identification code like `|hbox_group|'. After
calling this routine, it is safe to put six more entries on |save_stack|.

In some cases integer-valued items are placed onto the
|save_stack| just below a |level_boundary| word, because this is a
convenient place to keep information that is supposed to ``pop up'' just
when the group has finished.
For example, when `\.{\\hbox to 100pt}\grp' is being treated, the 100pt
dimension is stored on |save_stack| just before |new_save_level| is
called.

We use the notation |saved(k)| to stand for an integer item that
appears in location |save_ptr+k| of the save stack.

@d saved(#)==save_stack[save_ptr+#].int

@p procedure new_save_level(@!c:group_code); {begin a new level of grouping}
begin check_full_save_stack;
saved(0):=line; incr(save_ptr);
save_type(save_ptr):=level_boundary; save_level(save_ptr):=cur_group;
save_index(save_ptr):=cur_boundary;
if cur_level=max_quarterword then overflow("grouping levels",
@:TeX capacity exceeded grouping levels}{\quad grouping levels@>
  max_quarterword-min_quarterword);
  {quit if |(cur_level+1)| is too big to be stored in |eqtb|}
cur_boundary:=save_ptr; cur_group:=c;
@!stat if tracing_groups>0 then group_trace(false);@+tats@;@/
incr(cur_level); incr(save_ptr);
end;

@ Just before an entry of |eqtb| is changed, the following procedure should
be called to update the other data structures properly. It is important
to keep in mind that reference counts in |mem| include references from
within |save_stack|, so these counts must be handled carefully.
@^reference counts@>

@p procedure eq_destroy(@!w:memory_word); {gets ready to forget |w|}
var q:pointer; {|equiv| field of |w|}
begin case eq_type_field(w) of
call,long_call,outer_call,long_outer_call: delete_token_ref(equiv_field(w));
glue_ref: delete_glue_ref(equiv_field(w));
shape_ref: begin q:=equiv_field(w); {we need to free a \.{\\parshape} block}
  if q<>null then flush_node(q);
  end; {such a block is |2n+1| words long, where |n=vinfo(q)|}
box_ref: flush_node_list(equiv_field(w));
othercases do_nothing
endcases;
end;

@ To save a value of |eqtb[p]| that was established at level |l|, we
can use the following subroutine.

@p procedure eq_save(@!p:pointer;@!l:quarterword); {saves |eqtb[p]|}
begin check_full_save_stack;
if l=level_zero then save_type(save_ptr):=restore_zero
else  begin save_stack[save_ptr]:=eqtb[p]; incr(save_ptr);
  save_type(save_ptr):=restore_old_value;
  end;
save_level(save_ptr):=l; save_index(save_ptr):=p; incr(save_ptr);
end;

@ The procedure |eq_define| defines an |eqtb| entry having specified
|eq_type| and |equiv| fields, and saves the former value if appropriate.
This procedure is used only for entries in the first four regions of |eqtb|,
i.e., only for entries that have |eq_type| and |equiv| fields.
After calling this routine, it is safe to put four more entries on
|save_stack|, provided that there was room for four more entries before
the call, since |eq_save| makes the necessary test.

@d assign_trace(#)==@!stat if tracing_assigns>0 then restore_trace(#);
  tats

@p procedure eq_define(@!p:pointer;@!t:quarterword;@!e:halfword);
  {new data for |eqtb|}
label exit;
begin if (eq_type(p)=t)and(equiv(p)=e) then
  begin assign_trace(p,"reassigning")@;@/
  eq_destroy(eqtb[p]); return;
  end;
assign_trace(p,"changing")@;@/
if eq_level(p)=cur_level then eq_destroy(eqtb[p])
else if cur_level>level_one then eq_save(p,eq_level(p));
eq_level(p):=cur_level; eq_type(p):=t; equiv(p):=e;
assign_trace(p,"into")@;@/
exit:end;

@ The counterpart of |eq_define| for the remaining (fullword) positions in
|eqtb| is called |eq_word_define|. Since |xeq_level[p]>=level_one| for all
|p|, a `|restore_zero|' will never be used in this case.

@p procedure eq_word_define(@!p:pointer;@!w:integer);
label exit;
begin if eqtb[p].int=w then
  begin assign_trace(p,"reassigning")@;@/
  return;
  end;
assign_trace(p,"changing")@;@/
if xeq_level[p]<>cur_level then
  begin eq_save(p,xeq_level[p]); xeq_level[p]:=cur_level;
  end;
eqtb[p].int:=w;
assign_trace(p,"into")@;@/
exit:end;

@ The |eq_define| and |eq_word_define| routines take care of local definitions.
@^global definitions@>
Global definitions are done in almost the same way, but there is no need
to save old values, and the new value is associated with |level_one|.

@p procedure geq_define(@!p:pointer;@!t:quarterword;@!e:halfword);
  {global |eq_define|}
begin assign_trace(p,"globally changing")@;@/
begin eq_destroy(eqtb[p]);
eq_level(p):=level_one; eq_type(p):=t; equiv(p):=e;
end;
assign_trace(p,"into")@;@/
end;
@#
procedure geq_word_define(@!p:pointer;@!w:integer); {global |eq_word_define|}
begin assign_trace(p,"globally changing")@;@/
begin eqtb[p].int:=w; xeq_level[p]:=level_one;
end;
assign_trace(p,"into")@;@/
end;

@ Subroutine |save_for_after| puts a token on the stack for save-keeping.

@p procedure save_for_after(@!t:halfword);
begin if cur_level>level_one then
  begin check_full_save_stack;
  save_type(save_ptr):=insert_token; save_level(save_ptr):=level_zero;
  save_index(save_ptr):=t; incr(save_ptr);
  end;
end;

@ The |unsave| routine goes the other way, taking items off of |save_stack|.
This routine takes care of restoration when a level ends; everything
belonging to the topmost group is cleared off of the save stack.

@p
procedure@?back_input; forward; @t\2@>
procedure unsave; {pops the top level off the save stack}
label done;
var p:pointer; {position to be restored}
@!l:quarterword; {saved level, if in fullword regions of |eqtb|}
@!t:halfword; {saved value of |cur_tok|}
@!a:boolean; {have we already processed an \.{\\aftergroup} ?}
begin a:=false; l:=level_one; {just in case}
unsave_math_codes(cur_level);
unsave_cat_codes (cat_code_table,cur_level);
unsave_text_codes(cur_level);
unsave_math_data(cur_level);
if cur_level>level_one then
  begin decr(cur_level);
  @<Clear off top level from |save_stack|@>;
  end
else confusion("curlevel"); {|unsave| is not used when |cur_group=bottom_level|}
@:this can't happen curlevel}{\quad curlevel@>
attr_list_cache:=cache_disabled;
end;

@ @<Clear off...@>=
loop@+begin decr(save_ptr);
  if save_type(save_ptr)=level_boundary then goto done;
  p:=save_index(save_ptr);
  if save_type(save_ptr)=insert_token then
    @<Insert token |p| into \TeX's input@>
  else  begin if save_type(save_ptr)=restore_old_value then
      begin l:=save_level(save_ptr); decr(save_ptr);
      end
    else save_stack[save_ptr]:=eqtb[undefined_control_sequence];
    @<Store \(s)|save_stack[save_ptr]| in |eqtb[p]|, unless
      |eqtb[p]| holds a global value@>;
    end;
  end;
done: @!stat if tracing_groups>0 then group_trace(true);@+tats@;@/
if grp_stack[in_open]=cur_boundary then group_warning;
  {groups possibly not properly nested with files}
cur_group:=save_level(save_ptr); cur_boundary:=save_index(save_ptr);
decr(save_ptr)

@ A global definition, which sets the level to |level_one|,
@^global definitions@>
will not be undone by |unsave|. If at least one global definition of
|eqtb[p]| has been carried out within the group that just ended, the
last such definition will therefore survive.

@<Store \(s)|save...@>=
if p<int_base then
  if eq_level(p)=level_one then
    begin eq_destroy(save_stack[save_ptr]); {destroy the saved value}
    @!stat if tracing_restores>0 then restore_trace(p,"retaining");@+tats@;@/
    end
  else  begin eq_destroy(eqtb[p]); {destroy the current value}
    eqtb[p]:=save_stack[save_ptr]; {restore the saved value}
    @!stat if tracing_restores>0 then restore_trace(p,"restoring");@+tats@;@/
    end
else if xeq_level[p]<>level_one then
  begin eqtb[p]:=save_stack[save_ptr]; xeq_level[p]:=l;
  @!stat if tracing_restores>0 then restore_trace(p,"restoring");@+tats@;@/
  end
else  begin
  @!stat if tracing_restores>0 then restore_trace(p,"retaining");@+tats@;@/
  end

@ @<Declare \eTeX\ procedures for tr...@>=
@!stat procedure restore_trace(@!p:pointer;@!s:str_number);
  {|eqtb[p]| has just been restored or retained}
begin begin_diagnostic; print_char("{"); print(s); print_char(" ");
show_eqtb(p); print_char("}");
end_diagnostic(false);
end;
tats

@ Most of the parameters kept in |eqtb| can be changed freely, but there's
an exception:  The magnification should not be used with two different
values during any \TeX\ job, since a single magnification is applied to an
entire run. The global variable |mag_set| is set to the current magnification
whenever it becomes necessary to ``freeze'' it at a particular value.

@<Glob...@>=
@!mag_set:integer; {if nonzero, this magnification should be used henceforth}

@ @<Set init...@>=
mag_set:=0;

@ The |prepare_mag| subroutine is called whenever \TeX\ wants to use |mag|
for magnification.

@p procedure prepare_mag;
begin if (mag_set>0)and(mag<>mag_set) then
  begin print_err("Incompatible magnification ("); print_int(mag);
@.Incompatible magnification@>
  print(");"); print_nl(" the previous value will be retained");
  help2("I can handle only one magnification ratio per job. So I've")@/
  ("reverted to the magnification you used earlier on this run.");@/
  int_error(mag_set);
  geq_word_define(int_base+mag_code,mag_set); {|mag:=mag_set|}
  end;
if (mag<=0)or(mag>32768) then
  begin print_err("Illegal magnification has been changed to 1000");@/
@.Illegal magnification...@>
  help1("The magnification ratio must be between 1 and 32768.");
  int_error(mag); geq_word_define(int_base+mag_code,1000);
  end;
if (mag_set=0) and (mag<>mag_set) then begin
  if mag<>1000 then
    one_true_inch:=xn_over_d(one_hundred_inch,10,mag)
  else
    one_true_inch:=one_inch;
end;
mag_set:=mag;
end;

@* \[20] Token lists.
A \TeX\ token is either a character or a control sequence, and it is
@^token@>
represented internally in one of two ways: (1)~A character whose ASCII
code number is |c| and whose command code is |m| is represented as the
number $2^{21}m+c$; the command code is in the range |1<=m<=14|. (2)~A control
sequence whose |eqtb| address is |p| is represented as the number
|cs_token_flag+p|. Here |cs_token_flag=@t$2^{25}-1$@>| is larger than
$2^{21}m+c$, yet it is small enough that |cs_token_flag+p< max_halfword|;
thus, a token fits comfortably in a halfword.

A token |t| represents a |left_brace| command if and only if
|t<left_brace_limit|; it represents a |right_brace| command if and only if
we have |left_brace_limit<=t<right_brace_limit|; and it represents a |match| or
|end_match| command if and only if |match_token<=t<=end_match_token|.
The following definitions take care of these token-oriented constants
and a few others.

@d cs_token_flag==@"1FFFFFFF {amount added to the |eqtb| location in a
  token that stands for a control sequence; is a multiple of~$2^{21}$, less~1}
@d left_brace_token=@"200000   {$2^{21}\cdot|left_brace|$}
@d left_brace_limit=@"400000   {$2^{21}\cdot(|left_brace|+1)$}
@d right_brace_token=@"400000  {$2^{21}\cdot|right_brace|$}
@d right_brace_limit=@"600000  {$2^{21}\cdot(|right_brace|+1)$}
@d math_shift_token= @"600000  {$2^{21}\cdot|math_shift|$}
@d tab_token=@"800000          {$2^{21}\cdot|tab_mark|$}
@d out_param_token=@"A00000    {$2^{21}\cdot|out_param|$}
@d space_token=@"1400020       {$2^{21}\cdot|spacer|+|" "|$}
@d letter_token=@"1600000      {$2^{21}\cdot|letter|$}
@d other_token=@"1800000       {$2^{21}\cdot|other_char|$}
@d match_token=@"1A00000       {$2^{21}\cdot|match|$}
@d end_match_token=@"1C00000   {$2^{21}\cdot|end_match|$}
@d protected_token=@"1C00001   {$2^{21}\cdot|end_match|+1$}

@ @<Check the ``constant''...@>=
if cs_token_flag+undefined_control_sequence>max_halfword then bad:=21;

@ A token list is a singly linked list of one-word nodes in |mem|, where
each word contains a token and a link. Macro definitions, output-routine
definitions, marks, \.{\\write} texts, and a few other things
are remembered by \TeX\ in the form
of token lists, usually preceded by a node with a reference count in its
|token_ref_count| field. The token stored in location |p| is called
|info(p)|.

Three special commands appear in the token lists of macro definitions.
When |m=match|, it means that \TeX\ should scan a parameter
for the current macro; when |m=end_match|, it means that parameter
matching should end and \TeX\ should start reading the macro text; and
when |m=out_param|, it means that \TeX\ should insert parameter
number |c| into the text at this point.

The enclosing \.{\char'173} and \.{\char'175} characters of a macro
definition are omitted, but the final right brace of an output routine
is included at the end of its token list.

Here is an example macro definition that illustrates these conventions.
After \TeX\ processes the text
$$\.{\\def\\mac a\#1\#2 \\b \{\#1\\-a \#\#1\#2 \#2\}}$$
the definition of \.{\\mac} is represented as a token list containing
$$\def\,{\hskip2pt}
\vbox{\halign{\hfil#\hfil\cr
(reference count), |letter|\,\.a, |match|\,\#, |match|\,\#, |spacer|\,\.\ ,
\.{\\b}, |end_match|,\cr
|out_param|\,1, \.{\\-}, |letter|\,\.a, |spacer|\,\.\ , |mac_param|\,\#,
|other_char|\,\.1,\cr
|out_param|\,2, |spacer|\,\.\ , |out_param|\,2.\cr}}$$
The procedure |scan_toks| builds such token lists, and |macro_call|
does the parameter matching.
@^reference counts@>

Examples such as
$$\.{\\def\\m\{\\def\\m\{a\}\ b\}}$$
explain why reference counts would be needed even if \TeX\ had no \.{\\let}
operation: When the token list for \.{\\m} is being read, the redefinition of
\.{\\m} changes the |eqtb| entry before the token list has been fully
consumed, so we dare not simply destroy a token list when its
control sequence is being redefined.

If the parameter-matching part of a definition ends with `\.{\#\{}',
the corresponding token list will have `\.\{' just before the `|end_match|'
and also at the very end. The first `\.\{' is used to delimit the parameter; the
second one keeps the first from disappearing.

@ The procedure |show_token_list|, which prints a symbolic form of
the token list that starts at a given node |p|, illustrates these
conventions. The token list being displayed should not begin with a reference
count. However, the procedure is intended to be robust, so that if the
memory links are awry or if |p| is not really a pointer to a token list,
nothing catastrophic will happen.

An additional parameter |q| is also given; this parameter is either null
or it points to a node in the token list where a certain magic computation
takes place that will be explained later. (Basically, |q| is non-null when
we are printing the two-line context information at the time of an error
message; |q| marks the place corresponding to where the second line
should begin.)

For example, if |p| points to the node containing the first \.a in the
token list above, then |show_token_list| will print the string
$$\hbox{`\.{a\#1\#2\ \\b\ ->\#1\\-a\ \#\#1\#2\ \#2}';}$$
and if |q| points to the node containing the second \.a,
the magic computation will be performed just before the second \.a is printed.

The generation will stop, and `\.{\\ETC.}' will be printed, if the length
of printing exceeds a given limit~|l|. Anomalous entries are printed in the
form of control sequences that are not followed by a blank space, e.g.,
`\.{\\BAD.}'; this cannot be confused with actual control sequences because
a real control sequence named \.{BAD} would come out `\.{\\BAD\ }'.

@<Declare the procedure called |show_token_list|@>=
procedure show_token_list(@!p,@!q:integer;@!l:integer);
label exit;
var m,@!c:integer; {pieces of a token}
@!match_chr:ASCII_code; {character used in a `|match|'}
@!n:ASCII_code; {the highest parameter number, as an ASCII digit}
begin match_chr:="#"; n:="0"; tally:=0;
while (p<>null) and (tally<l) do
  begin if p=q then @<Do magic computation@>;
  @<Display token |p|, and |return| if there are problems@>;
  p:=link(p);
  end;
if p<>null then print_esc("ETC.");
@.ETC@>
exit:
end;

@ @<Display token |p|...@>=
if (p<fix_mem_min) or (p>fix_mem_end) then
  begin print_esc("CLOBBERED."); return;
@.CLOBBERED@>
  end;
if info(p)>=cs_token_flag then begin
  if not ((inhibit_par_tokens) and (info(p)=par_token)) then
          print_cs(info(p)-cs_token_flag);
  end
else  begin m:=info(p) div string_offset; c:=info(p) mod string_offset;
  if info(p)<0 then print_esc("BAD.")
@.BAD@>
  else @<Display the token $(|m|,|c|)$@>;
  end

@ The procedure usually ``learns'' the character code used for macro
parameters by seeing one in a |match| command before it runs into any
|out_param| commands.

@<Display the token ...@>=
case m of
left_brace,right_brace,math_shift,tab_mark,sup_mark,sub_mark,spacer,
  letter,other_char: print(c);
mac_param: begin if not in_lua_escape then print(c); print(c);
  end;
out_param: begin print(match_chr);
  if c<=9 then print_char(c+"0")
  else  begin print_char("!"); return;
    end;
  end;
match: begin match_chr:=c; print(c); incr(n); print_char(n);
  if n>"9" then return;
  end;
end_match: if c=0 then print("->");
@.->@>
othercases print_esc("BAD.")
@.BAD@>
endcases

@ Here's the way we sometimes want to display a token list, given a pointer
to its reference count; the pointer may be null.

@p procedure token_show(@!p:pointer);
begin if p<>null then show_token_list(link(p),null,10000000);
end;

@ The |print_meaning| subroutine displays |cur_cmd| and |cur_chr| in
symbolic form, including the expansion of a macro or mark.

@p procedure print_meaning;
begin print_cmd_chr(cur_cmd,cur_chr);
if cur_cmd>=call then
  begin print_char(":"); print_ln; token_show(cur_chr);
  end
else  @<Show the meaning of a mark node@>;
end;

@* \[21] Introduction to the syntactic routines.
Let's pause a moment now and try to look at the Big Picture.
The \TeX\ program consists of three main parts: syntactic routines,
semantic routines, and output routines. The chief purpose of the
syntactic routines is to deliver the user's input to the semantic routines,
one token at a time. The semantic routines act as an interpreter
responding to these tokens, which may be regarded as commands. And the
output routines are periodically called on to convert box-and-glue
lists into a compact set of instructions that will be sent
to a typesetter. We have discussed the basic data structures and utility
routines of \TeX, so we are good and ready to plunge into the real activity by
considering the syntactic routines.

Our current goal is to come to grips with the |get_next| procedure,
which is the keystone of \TeX's input mechanism. Each call of |get_next|
sets the value of three variables |cur_cmd|, |cur_chr|, and |cur_cs|,
representing the next input token.
$$\vbox{\halign{#\hfil\cr
  \hbox{|cur_cmd| denotes a command code from the long list of codes
   given above;}\cr
  \hbox{|cur_chr| denotes a character code or other modifier of the command
   code;}\cr
  \hbox{|cur_cs| is the |eqtb| location of the current control sequence,}\cr
  \hbox{\qquad if the current token was a control sequence,
   otherwise it's zero.}\cr}}$$
Underlying this external behavior of |get_next| is all the machinery
necessary to convert from character files to tokens. At a given time we
may be only partially finished with the reading of several files (for
which \.{\\input} was specified), and partially finished with the expansion
of some user-defined macros and/or some macro parameters, and partially
finished with the generation of some text in a template for \.{\\halign},
and so on. When reading a character file, special characters must be
classified as math delimiters, etc.; comments and extra blank spaces must
be removed, paragraphs must be recognized, and control sequences must be
found in the hash table. Furthermore there are occasions in which the
scanning routines have looked ahead for a word like `\.{plus}' but only
part of that word was found, hence a few characters must be put back
into the input and scanned again.

To handle these situations, which might all be present simultaneously,
\TeX\ uses various stacks that hold information about the incomplete
activities, and there is a finite state control for each level of the
input mechanism. These stacks record the current state of an implicitly
recursive process, but the |get_next| procedure is not recursive.
Therefore it will not be difficult to translate these algorithms into
low-level languages that do not support recursion.

@<Glob...@>=
@!cur_cmd: eight_bits; {current command set by |get_next|}
@!cur_chr: halfword; {operand of current command}
@!cur_cs: pointer; {control sequence found here, zero if none found}
@!cur_tok: halfword; {packed representative of |cur_cmd| and |cur_chr|}

@ Here is a procedure that displays the current command.

@p procedure show_cur_cmd_chr;
var n:integer; {level of \.{\\if...\\fi} nesting}
@!l:integer; {line where \.{\\if} started}
@!p:pointer;
begin begin_diagnostic; print_nl("{");
if mode<>shown_mode then
  begin print_mode(mode); print(": "); shown_mode:=mode;
  end;
print_cmd_chr(cur_cmd,cur_chr);
if tracing_ifs>0 then
  if cur_cmd>=if_test then if cur_cmd<=fi_or_else then
    begin print(": ");
    if cur_cmd=fi_or_else then
      begin print_cmd_chr(if_test,cur_if); print_char(" ");
      n:=0; l:=if_line;
      end
    else  begin n:=1; l:=line;
      end;
    p:=cond_ptr;
    while p<>null do
      begin incr(n); p:=vlink(p);
      end;
    print("(level "); print_int(n); print_char(")"); print_if_line(l);
    end;
print_char("}");
end_diagnostic(false);
end;

@* \[22] Input stacks and states.
This implementation of
\TeX\ uses two different conventions for representing sequential stacks.
@^stack conventions@>@^conventions for representing stacks@>

\yskip\hangg 1) If there is frequent access to the top entry, and if the
stack is essentially never empty, then the top entry is kept in a global
variable (even better would be a machine register), and the other entries
appear in the array $\\{stack}[0\to(\\{ptr}-1)]$. For example, the
semantic stack described above is handled this way, and so is the input
stack that we are about to study.

\yskip\hangg 2) If there is infrequent top access, the entire stack contents
are in the array $\\{stack}[0\to(\\{ptr}-1)]$. For example, the |save_stack|
is treated this way, as we have seen.

\yskip\noindent
The state of \TeX's input mechanism appears in the input stack, whose
entries are records with six fields, called |state|, |index|, |start|, |loc|,
|limit|, and |name|. This stack is maintained with
convention~(1), so it is declared in the following way:

@<Types...@>=
@!in_state_record = record
  @!state_field, @!index_field: quarterword;
  @!start_field,@!loc_field, @!limit_field, @!name_field,
  @!ocp_lstack_field: halfword; {used for omega translation processes}
  @!ocp_no_field: halfword; {used for omega translation processes}
  @!synctex_tag_field: integer; {stack the tag of the current file}
  @!cattable_field: integer; {category table used by the current line (see textoken.c)}
  @!partial_field: boolean; {is the current line partial? (see textoken.c)}
  @!nofilter_field: boolean; {used by token filtering}
  end;

@ @<Glob...@>=
@!input_stack : array[0..stack_size] of in_state_record;
@!input_ptr : 0..stack_size; {first unused location of |input_stack|}
@!max_in_stack: 0..stack_size; {largest value of |input_ptr| when pushing}
@!cur_input : in_state_record;
  {the ``top'' input state, according to convention (1)}

@ We've already defined the special variable |loc==cur_input.loc_field|
in our discussion of basic input-output routines. The other components of
|cur_input| are defined in the same way:

@d state==cur_input.state_field {current scanner state}
@d index==cur_input.index_field {reference for buffer information}
@d start==cur_input.start_field {starting position in |buffer|}
@d limit==cur_input.limit_field {end of current line in |buffer|}
@d nofilter==cur_input.nofilter_field {is token filtering explicitly disallowed?}
@d name==cur_input.name_field {name of the current file}
@d synctex_tag==cur_input.synctex_tag_field {{\sl Sync\TeX} tag of the current file}
@d current_ocp_lstack==cur_input.ocp_lstack_field {name of the current ocp}
@d current_ocp_no==cur_input.ocp_no_field {name of the current ocp}
@d line_catcode_table==cur_input.cattable_field
@d line_partial==cur_input.partial_field

@ Let's look more closely now at the control variables
(|state|,~|index|,~|start|,~|loc|,~|limit|,~|name|),
assuming that \TeX\ is reading a line of characters that have been input
from some file or from the user's terminal. There is an array called
|buffer| that acts as a stack of all lines of characters that are
currently being read from files, including all lines on subsidiary
levels of the input stack that are not yet completed. \TeX\ will return to
the other lines when it is finished with the present input file.

(Incidentally, on a machine with byte-oriented addressing, it might be
appropriate to combine |buffer| with the |str_pool| array,
letting the buffer entries grow downward from the top of the string pool
and checking that these two tables don't bump into each other.)

The line we are currently working on begins in position |start| of the
buffer; the next character we are about to read is |buffer[loc]|; and
|limit| is the location of the last character present.  If |loc>limit|,
the line has been completely read. Usually |buffer[limit]| is the
|end_line_char|, denoting the end of a line, but this is not
true if the current line is an insertion that was entered on the user's
terminal in response to an error message.

The |name| variable is a string number that designates the name of
the current file, if we are reading a text file. It is zero if we
are reading from the terminal; it is |n+1| if we are reading from
input stream |n|, where |0<=n<=16|. (Input stream 16 stands for
an invalid stream number; in such cases the input is actually from
the terminal, under control of the procedure |read_toks|.)
Finally |18<=name<=20| indicates that we are reading a pseudo file
created by the \.{\\scantokens} or \.{\\scantextokens} command.

The |state| variable has one of three values, when we are scanning such
files:
$$\baselineskip 15pt\vbox{\halign{#\hfil\cr
1) |state=mid_line| is the normal state.\cr
2) |state=skip_blanks| is like |mid_line|, but blanks are ignored.\cr
3) |state=new_line| is the state at the beginning of a line.\cr}}$$
These state values are assigned numeric codes so that if we add the state
code to the next character's command code, we get distinct values. For
example, `|mid_line+spacer|' stands for the case that a blank
space character occurs in the middle of a line when it is not being
ignored; after this case is processed, the next value of |state| will
be |skip_blanks|.

@d mid_line=1 {|state| code when scanning a line of characters}
@d skip_blanks=2+max_char_code {|state| code when ignoring blanks}
@d new_line=3+max_char_code+max_char_code {|state| code at start of line}

@ Additional information about the current line is available via the
|index| variable, which counts how many lines of characters are present
in the buffer below the current level. We have |index=0| when reading
from the terminal and prompting the user for each line; then if the user types,
e.g., `\.{\\input paper}', we will have |index=1| while reading
the file \.{paper.tex}. However, it does not follow that |index| is the
same as the input stack pointer, since many of the levels on the input
stack may come from token lists. For example, the instruction `\.{\\input
paper}' might occur in a token list.

The global variable |in_open| is equal to the |index|
value of the highest non-token-list level. Thus, the number of partially read
lines in the buffer is |in_open+1|, and we have |in_open=index|
when we are not reading a token list.

If we are not currently reading from the terminal, or from an input
stream, we are reading from the file variable |input_file[index]|. We use
the notation |terminal_input| as a convenient abbreviation for |name=0|,
and |cur_file| as an abbreviation for |input_file[index]|.

The global variable |line| contains the line number in the topmost
open file, for use in error messages. If we are not reading from
the terminal, |line_stack[index]| holds the line number for the
enclosing level, so that |line| can be restored when the current
file has been read. Line numbers should never be negative, since the
negative of the current line number is used to identify the user's output
routine in the |mode_line| field of the semantic nest entries.

If more information about the input state is needed, it can be
included in small arrays like those shown here. For example,
the current page or segment number in the input file might be
put into a variable |@!page|, maintained for enclosing levels in
`\ignorespaces|@!page_stack:array[1..max_in_open] of integer|\unskip'
by analogy with |line_stack|.
@^system dependencies@>

@d terminal_input==(name=0) {are we reading from the terminal?}
@d cur_file==input_file[index] {the current |alpha_file| variable}

@<Glob...@>=
@!in_open : 0..max_in_open; {the number of lines in the buffer, less one}
@!open_parens : 0..max_in_open; {the number of open text files}
@!input_file : array[1..max_in_open] of alpha_file;
@!line : integer; {current line number in the current source file}
@!line_stack : array[1..max_in_open] of integer;

@ Users of \TeX\ sometimes forget to balance left and right braces properly,
and one of the ways \TeX\ tries to spot such errors is by considering an
input file as broken into subfiles by control sequences that
are declared to be \.{\\outer}.

A variable called |scanner_status| tells \TeX\ whether or not to complain
when a subfile ends. This variable has six possible values:

\yskip\hang|normal|, means that a subfile can safely end here without incident.

\yskip\hang|skipping|, means that a subfile can safely end here, but not a file,
because we're reading past some conditional text that was not selected.

\yskip\hang|defining|, means that a subfile shouldn't end now because a
macro is being defined.

\yskip\hang|matching|, means that a subfile shouldn't end now because a
macro is being used and we are searching for the end of its arguments.

\yskip\hang|aligning|, means that a subfile shouldn't end now because we are
not finished with the preamble of an \.{\\halign} or \.{\\valign}.

\yskip\hang|absorbing|, means that a subfile shouldn't end now because we are
reading a balanced token list for \.{\\message}, \.{\\write}, etc.

\yskip\noindent
If the |scanner_status| is not |normal|, the variable |warning_index| points
to the |eqtb| location for the relevant control sequence name to print
in an error message.

@d skipping=1 {|scanner_status| when passing conditional text}
@d defining=2 {|scanner_status| when reading a macro definition}
@d matching=3 {|scanner_status| when reading macro arguments}
@d aligning=4 {|scanner_status| when reading an alignment preamble}
@d absorbing=5 {|scanner_status| when reading a balanced text}

@<Glob...@>=
@!scanner_status : normal..absorbing; {can a subfile end now?}
@!warning_index : pointer; {identifier relevant to non-|normal| scanner status}
@!def_ref : pointer; {reference count of token list being defined}

@ Here is a procedure that uses |scanner_status| to print a warning message
when a subfile has ended, and at certain other crucial times:

@<Declare the procedure called |runaway|@>=
procedure runaway;
var p:pointer; {head of runaway list}
begin p:=null;
  if scanner_status>skipping then
  begin print_nl("Runaway ");
@.Runaway...@>
  case scanner_status of
  defining: begin print("definition"); p:=def_ref;
    end;
  matching: begin print("argument"); p:=temp_token_head;
    end;
  aligning: begin print("preamble"); p:=hold_token_head;
    end;
  absorbing: begin print("text"); p:=def_ref;
    end;
  end; {there are no other cases}
  print_char("?");print_ln; show_token_list(link(p),null,error_line-10);
  end;
end;

@ However, all this discussion about input state really applies only to the
case that we are inputting from a file. There is another important case,
namely when we are currently getting input from a token list. In this case
|state=token_list|, and the conventions about the other state variables
are different:

\yskip\hang|loc| is a pointer to the current node in the token list, i.e.,
the node that will be read next. If |loc=null|, the token list has been
fully read.

\yskip\hang|start| points to the first node of the token list; this node
may or may not contain a reference count, depending on the type of token
list involved.

\yskip\hang|token_type|, which takes the place of |index| in the
discussion above, is a code number that explains what kind of token list
is being scanned.

\yskip\hang|name| points to the |eqtb| address of the control sequence
being expanded, if the current token list is a macro.

\yskip\hang|param_start|, which takes the place of |limit|, tells where
the parameters of the current macro begin in the |param_stack|, if the
current token list is a macro.

\yskip\noindent The |token_type| can take several values, depending on
where the current token list came from:

\yskip\hang|parameter|, if a parameter is being scanned;

\hang|u_template|, if the \<u_j> part of an alignment
template is being scanned;

\hang|v_template|, if the \<v_j> part of an alignment
template is being scanned;

\hang|backed_up|, if the token list being scanned has been inserted as
`to be read again'.

\hang|inserted|, if the token list being scanned has been inserted as
the text expansion of a \.{\\count} or similar variable;

\hang|macro|, if a user-defined control sequence is being scanned;

\hang|output_text|, if an \.{\\output} routine is being scanned;

\hang|every_par_text|, if the text of \.{\\everypar} is being scanned;

\hang|every_math_text|, if the text of \.{\\everymath} is being scanned;

\hang|every_display_text|, if the text of \.{\\everydisplay} is being scanned;

\hang|every_hbox_text|, if the text of \.{\\everyhbox} is being scanned;

\hang|every_vbox_text|, if the text of \.{\\everyvbox} is being scanned;

\hang|every_job_text|, if the text of \.{\\everyjob} is being scanned;

\hang|every_cr_text|, if the text of \.{\\everycr} is being scanned;

\hang|mark_text|, if the text of a \.{\\mark} is being scanned;

\hang|write_text|, if the text of a \.{\\write} is being scanned.

\yskip\noindent
The codes for |output_text|, |every_par_text|, etc., are equal to a constant
plus the corresponding codes for token list parameters |output_routine_loc|,
|every_par_loc|, etc.  The token list begins with a reference count if and
only if |token_type>=macro|.
@^reference counts@>

Since \eTeX's additional token list parameters precede |toks_base|, the
corresponding token types must precede |write_text|.

@d token_list=0 {|state| code when scanning a token list}
@d token_type==index {type of current token list}
@d param_start==limit {base of macro parameters in |param_stack|}
@d parameter=0 {|token_type| code for parameter}
@d u_template=1 {|token_type| code for \<u_j> template}
@d v_template=2 {|token_type| code for \<v_j> template}
@d backed_up=3 {|token_type| code for text to be reread}
@d inserted=4 {|token_type| code for inserted texts}
@d macro=5 {|token_type| code for defined control sequences}
@d output_text=6 {|token_type| code for output routines}
@d every_par_text=7 {|token_type| code for \.{\\everypar}}
@d every_math_text=8 {|token_type| code for \.{\\everymath}}
@d every_display_text=9 {|token_type| code for \.{\\everydisplay}}
@d every_hbox_text=10 {|token_type| code for \.{\\everyhbox}}
@d every_vbox_text=11 {|token_type| code for \.{\\everyvbox}}
@d every_job_text=12 {|token_type| code for \.{\\everyjob}}
@d every_cr_text=13 {|token_type| code for \.{\\everycr}}
@d mark_text=14 {|token_type| code for \.{\\topmark}, etc.}
@#
@d eTeX_text_offset=output_routine_loc-output_text
@d every_eof_text=every_eof_loc-eTeX_text_offset
  {|token_type| code for \.{\\everyeof}}
@#
@d write_text=etex_toks-eTeX_text_offset {|token_type| code for \.{\\write}}

@ The |param_stack| is an auxiliary array used to hold pointers to the token
lists for parameters at the current level and subsidiary levels of input.
This stack is maintained with convention (2), and it grows at a different
rate from the others.

@<Glob...@>=
@!param_stack:array [0..param_size] of pointer;
  {token list pointers for parameters}
@!param_ptr:0..param_size; {first unused entry in |param_stack|}
@!max_param_stack:integer;
  {largest value of |param_ptr|, will be |<=param_size+9|}

@ The input routines must also interact with the processing of
\.{\\halign} and \.{\\valign}, since the appearance of tab marks and
\.{\\cr} in certain places is supposed to trigger the beginning of special
\<v_j> template text in the scanner. This magic is accomplished by an
|align_state| variable that is increased by~1 when a `\.{\char'173}' is
scanned and decreased by~1 when a `\.{\char'175}' is scanned. The |align_state|
is nonzero during the \<u_j> template, after which it is set to zero; the
\<v_j> template begins when a tab mark or \.{\\cr} occurs at a time that
|align_state=0|.

@<Glob...@>=
@!align_state:integer; {group level with respect to current alignment}

@ Thus, the ``current input state'' can be very complicated indeed; there
can be many levels and each level can arise in a variety of ways. The
|show_context| procedure, which is used by \TeX's error-reporting routine to
print out the current input state on all levels down to the most recent
line of characters from an input file, illustrates most of these conventions.
The global variable |base_ptr| contains the lowest level that was
displayed by this procedure.

@<Glob...@>=
@!base_ptr:0..stack_size; {shallowest level shown by |show_context|}

@ The status at each level is indicated by printing two lines, where the first
line indicates what was read so far and the second line shows what remains
to be read. The context is cropped, if necessary, so that the first line
contains at most |half_error_line| characters, and the second contains
at most |error_line|. Non-current input levels whose |token_type| is
`|backed_up|' are shown only if they have not been fully read.

@p procedure show_context; {prints where the scanner is}
label done;
var old_setting:0..max_selector; {saved |selector| setting}
@!nn:integer; {number of contexts shown so far, less one}
@!bottom_line:boolean; {have we reached the final context to be shown?}
@<Local variables for formatting calculations@>@/
begin base_ptr:=input_ptr; input_stack[base_ptr]:=cur_input;
  {store current state}
nn:=-1; bottom_line:=false;
loop@+begin cur_input:=input_stack[base_ptr]; {enter into the context}
  if (state<>token_list) then
    if (name>21) or (base_ptr=0) then bottom_line:=true;
  if (base_ptr=input_ptr)or bottom_line or(nn<error_context_lines) then
    @<Display the current context@>
  else if nn=error_context_lines then
    begin print_nl("..."); incr(nn); {omitted if |error_context_lines<0|}
    end;
  if bottom_line then goto done;
  decr(base_ptr);
  end;
done: cur_input:=input_stack[input_ptr]; {restore original state}
end;

@ @<Display the current context@>=
begin if (base_ptr=input_ptr) or (state<>token_list) or
   (token_type<>backed_up) or (loc<>null) then
    {we omit backed-up token lists that have already been read}
  begin tally:=0; {get ready to count characters}
  old_setting:=selector;
  if current_ocp_lstack>0 then
  begin print_nl("OCP stack "); print_scaled(current_ocp_lstack);
        print(" entry "); print_int(current_ocp_no); print(":");
    @<Pseudoprint the line@>;
  end
  else if state<>token_list then
    begin @<Print location of current line@>;
    @<Pseudoprint the line@>;
    end
  else  begin @<Print type of token list@>;
    @<Pseudoprint the token list@>;
    end;
  selector:=old_setting; {stop pseudoprinting}
  @<Print two lines using the tricky pseudoprinted information@>;
  incr(nn);
  end;
end

@ This routine should be changed, if necessary, to give the best possible
indication of where the current line resides in the input file.
For example, on some systems it is best to print both a page and line number.
@^system dependencies@>

@<Print location of current line@>=
if name<=17 then
  if terminal_input then
    if base_ptr=0 then print_nl("<*>") else print_nl("<insert> ")
  else  begin print_nl("<read ");
    if name=17 then print_char("*")@+else print_int(name-1);
@.*\relax@>
    print_char(">");
    end
else if index<>in_open then {input from a pseudo file}
  begin print_nl("l."); print_int(line_stack[index+1]);
  end
else  begin print_nl("l."); print_int(line);
  end;
print_char(" ")

@ @<Print type of token list@>=
case token_type of
parameter: print_nl("<argument> ");
u_template,v_template: print_nl("<template> ");
backed_up: if loc=null then print_nl("<recently read> ")
  else print_nl("<to be read again> ");
inserted: print_nl("<inserted text> ");
macro: begin print_ln; print_cs(name);
  end;
output_text: print_nl("<output> ");
every_par_text: print_nl("<everypar> ");
every_math_text: print_nl("<everymath> ");
every_display_text: print_nl("<everydisplay> ");
every_hbox_text: print_nl("<everyhbox> ");
every_vbox_text: print_nl("<everyvbox> ");
every_job_text: print_nl("<everyjob> ");
every_cr_text: print_nl("<everycr> ");
mark_text: print_nl("<mark> ");
every_eof_text: print_nl("<everyeof> ");
write_text: print_nl("<write> ");
othercases print_nl("?") {this should never happen}
endcases

@ Here it is necessary to explain a little trick. We don't want to store a long
string that corresponds to a token list, because that string might take up
lots of memory; and we are printing during a time when an error message is
being given, so we dare not do anything that might overflow one of \TeX's
tables. So `pseudoprinting' is the answer: We enter a mode of printing
that stores characters into a buffer of length |error_line|, where character
$k+1$ is placed into \hbox{|trick_buf[k mod error_line]|} if
|k<trick_count|, otherwise character |k| is dropped. Initially we set
|tally:=0| and |trick_count:=1000000|; then when we reach the
point where transition from line 1 to line 2 should occur, we
set |first_count:=tally| and |trick_count:=@tmax@>(error_line,
tally+1+error_line-half_error_line)|. At the end of the
pseudoprinting, the values of |first_count|, |tally|, and
|trick_count| give us all the information we need to print the two lines,
and all of the necessary text is in |trick_buf|.

Namely, let |l| be the length of the descriptive information that appears
on the first line. The length of the context information gathered for that
line is |k=first_count|, and the length of the context information
gathered for line~2 is $m=\min(|tally|, |trick_count|)-k$. If |l+k<=h|,
where |h=half_error_line|, we print |trick_buf[0..k-1]| after the
descriptive information on line~1, and set |n:=l+k|; here |n| is the
length of line~1. If $l+k>h$, some cropping is necessary, so we set |n:=h|
and print `\.{...}' followed by
$$\hbox{|trick_buf[(l+k-h+3)..k-1]|,}$$
where subscripts of |trick_buf| are circular modulo |error_line|. The
second line consists of |n|~spaces followed by |trick_buf[k..(k+m-1)]|,
unless |n+m>error_line|; in the latter case, further cropping is done.
This is easier to program than to explain.

@<Local variables for formatting...@>=
@!i:0..buf_size; {index into |buffer|}
@!j:0..buf_size; {end of current line in |buffer|}
@!l:0..half_error_line; {length of descriptive information on line 1}
@!m:integer; {context information gathered for line 2}
@!n:0..error_line; {length of line 1}
@!p: integer; {starting or ending place in |trick_buf|}
@!q: integer; {temporary index}

@ The following code sets up the print routines so that they will gather
the desired information.

@d begin_pseudoprint==
  begin l:=tally; tally:=0; selector:=pseudo;
  trick_count:=1000000;
  end
@d set_trick_count==
  begin first_count:=tally;
  trick_count:=tally+1+error_line-half_error_line;
  if trick_count<error_line then trick_count:=error_line;
  end

@ And the following code uses the information after it has been gathered.

@<Print two lines using the tricky pseudoprinted information@>=
if trick_count=1000000 then set_trick_count;
  {|set_trick_count| must be performed}
if tally<trick_count then m:=tally-first_count
else m:=trick_count-first_count; {context on line 2}
if l+first_count<=half_error_line then
  begin p:=0; n:=l+first_count;
  end
else  begin print("..."); p:=l+first_count-half_error_line+3;
  n:=half_error_line;
  end;
for q:=p to first_count-1 do print_char(trick_buf[q mod error_line]);
print_ln;
for q:=1 to n do print_char(" "); {print |n| spaces to begin line~2}
if m+n<=error_line then p:=first_count+m else p:=first_count+(error_line-n-3);
for q:=first_count to p-1 do print_char(trick_buf[q mod error_line]);
if m+n>error_line then print("...")

@ But the trick is distracting us from our current goal, which is to
understand the input state. So let's concentrate on the data structures that
are being pseudoprinted as we finish up the |show_context| procedure.

@<Pseudoprint the line@>=
begin_pseudoprint;
if buffer[limit]=end_line_char then j:=limit
else j:=limit+1; {determine the effective end of the line}
if j>0 then for i:=start to j-1 do
  begin if i=loc then set_trick_count;
  print_char(buffer[i]);
  end

@ @<Pseudoprint the token list@>=
begin_pseudoprint;
if token_type<macro then show_token_list(start,loc,100000)
else show_token_list(link(start),loc,100000) {avoid reference count}

@ Here is the missing piece of |show_token_list| that is activated when the
token beginning line~2 is about to be shown:

@<Do magic computation@>=set_trick_count

@* \[23] Maintaining the input stacks.
The following subroutines change the input status in commonly needed ways.

First comes |push_input|, which stores the current state and creates a
new level (having, initially, the same properties as the old).

@d push_input==@t@> {enter a new input level, save the old}
  begin if input_ptr>max_in_stack then
    begin max_in_stack:=input_ptr;
    if input_ptr=stack_size then overflow("input stack size",stack_size);
@:TeX capacity exceeded input stack size}{\quad input stack size@>
    end;
  input_stack[input_ptr]:=cur_input; {stack the record}
  nofilter:=false;
  incr(input_ptr);
  end

@ And of course what goes up must come down.

@d pop_input==@t@> {leave an input level, re-enter the old}
  begin decr(input_ptr); cur_input:=input_stack[input_ptr];
  end

@ Here is a procedure that starts a new level of token-list input, given
a token list |p| and its type |t|. If |t=macro|, the calling routine should
set |name| and |loc|.

@d back_list(#)==begin_token_list(#,backed_up) {backs up a simple token list}
@d ins_list(#)==begin_token_list(#,inserted) {inserts a simple token list}

@p procedure begin_token_list(@!p:pointer;@!t:quarterword);
begin push_input; state:=token_list; start:=p; token_type:=t;
if t>=macro then {the token list starts with a reference count}
  begin add_token_ref(p);
  if t=macro then param_start:=param_ptr
  else  begin loc:=link(p);
    if tracing_macros>1 then
      begin begin_diagnostic; print_nl("");
      case t of
      mark_text:print_esc("mark");
      write_text:print_esc("write");
      othercases print_cmd_chr(assign_toks,t-output_text+output_routine_loc)
      endcases;@/
      print("->"); token_show(p); end_diagnostic(false);
      end;
    end;
  end
else loc:=p;
end;

@ When a token list has been fully scanned, the following computations
should be done as we leave that level of input. The |token_type| tends
to be equal to either |backed_up| or |inserted| about 2/3 of the time.
@^inner loop@>

@p procedure end_token_list; {leave a token-list input level}
begin if token_type>=backed_up then {token list to be deleted}
  begin if token_type<=inserted then flush_list(start)
  else  begin delete_token_ref(start); {update reference count}
    if token_type=macro then {parameters must be flushed}
      while param_ptr>param_start do
        begin decr(param_ptr);
        flush_list(param_stack[param_ptr]);
        end;
    end;
  end
else if token_type=u_template then begin
  if align_state>500000 then align_state:=0
  else fatal_error("(interwoven alignment preambles are not allowed)");
@.interwoven alignment preambles...@>
  end;
pop_input;
check_interrupt;
end;

@ Sometimes \TeX\ has read too far and wants to ``unscan'' what it has
seen. The |back_input| procedure takes care of this by putting the token
just scanned back into the input stream, ready to be read again. This
procedure can be used only if |cur_tok| represents the token to be
replaced. Some applications of \TeX\ use this procedure a lot,
so it has been slightly optimized for speed.
@^inner loop@>

@p procedure back_input; {undoes one token of input}
var p:pointer; {a token list of length one}
begin while (state=token_list)and(loc=null)and(token_type<>v_template) do
  end_token_list; {conserve stack space}
p:=get_avail; info(p):=cur_tok;
if cur_tok<right_brace_limit then begin
  if cur_tok<left_brace_limit then decr(align_state)
  else incr(align_state);
  end;
push_input; state:=token_list; start:=p; token_type:=backed_up;
loc:=p; {that was |back_list(p)|, without procedure overhead}
end;

@ @<Insert token |p| into \TeX's input@>=
begin t:=cur_tok; cur_tok:=p;
if a then
  begin p:=get_avail; info(p):=cur_tok; link(p):=loc; loc:=p; start:=p;
  if cur_tok<right_brace_limit then begin
    if cur_tok<left_brace_limit then decr(align_state)
    else incr(align_state);
    end;
  end
else  begin back_input; a:=1; { etex is always on }
  end;
cur_tok:=t;
end

@ The |back_error| routine is used when we want to replace an offending token
just before issuing an error message. This routine, like |back_input|,
requires that |cur_tok| has been set. We disable interrupts during the
call of |back_input| so that the help message won't be lost.

@p procedure back_error; {back up one token and call |error|}
begin OK_to_interrupt:=false; back_input; OK_to_interrupt:=true; error;
end;
@#
procedure ins_error; {back up one inserted token and call |error|}
begin OK_to_interrupt:=false; back_input; token_type:=inserted;
OK_to_interrupt:=true; error;
end;

@ The |begin_file_reading| procedure starts a new level of input for lines
of characters to be read from a file, or as an insertion from the
terminal. It does not take care of opening the file, nor does it set |loc|
or |limit| or |line|.
@^system dependencies@>

@p procedure begin_file_reading;
begin if in_open=max_in_open then overflow("text input levels",max_in_open);
@:TeX capacity exceeded text input levels}{\quad text input levels@>
if first=buf_size then check_buffer_overflow(first);
@:TeX capacity exceeded buffer size}{\quad buffer size@>
incr(in_open); push_input; index:=in_open;
eof_seen[index]:=false;
grp_stack[index]:=cur_boundary; if_stack[index]:=cond_ptr;
line_stack[index]:=line; start:=first; state:=mid_line;
name:=0; {|terminal_input| is now |true|}
line_catcode_table:=DEFAULT_CAT_TABLE; line_partial:=false;
@<Prepare terminal input {\sl Sync\TeX} information@>;
end;

@ Conversely, the variables must be downdated when such a level of input
is finished:

@p procedure end_file_reading;
begin first:=start; line:=line_stack[index];
if (name>=18)and(name<=20) then pseudo_close else
if name=21 then luacstring_close(index) else
if name>17 then lua_a_close_in(cur_file,0); {forget it}
pop_input; decr(in_open);
end;

@ In order to keep the stack from overflowing during a long sequence of
inserted `\.{\\show}' commands, the following routine removes completed
error-inserted lines from memory.

@p procedure clear_for_error_prompt;
begin while (state<>token_list)and terminal_input and@|
  (input_ptr>0)and(loc>limit) do end_file_reading;
print_ln; clear_terminal;
end;

@ To get \TeX's whole input mechanism going, we perform the following
actions.

@<Initialize the input routines@>=
begin input_ptr:=0; max_in_stack:=0;
in_open:=0; open_parens:=0; max_buf_stack:=0;
grp_stack[0]:=0; if_stack[0]:=null;
param_ptr:=0; max_param_stack:=0;
first:=buf_size; repeat buffer[first]:=0; decr(first); until first=0;
scanner_status:=normal; warning_index:=null; first:=1;
state:=new_line; start:=1; index:=0; line:=0; name:=0;
current_ocp_lstack:=0; current_ocp_no:=0; nofilter:=false;
force_eof:=false; luacstrings :=0;
line_catcode_table:=DEFAULT_CAT_TABLE; line_partial:=false;
align_state:=1000000;@/
if not init_terminal then goto final_end;
limit:=last; first:=last+1; {|init_terminal| has set |loc| and |last|}
end

@* \[24] Getting the next token.
The heart of \TeX's input mechanism is the |get_next| procedure, which
we shall develop in the next few sections of the program. Perhaps we
shouldn't actually call it the ``heart,'' however, because it really acts
as \TeX's eyes and mouth, reading the source files and gobbling them up.
And it also helps \TeX\ to regurgitate stored token lists that are to be
processed again.
@^eyes and mouth@>

The main duty of |get_next| is to input one token and to set |cur_cmd|
and |cur_chr| to that token's command code and modifier. Furthermore, if
the input token is a control sequence, the |eqtb| location of that control
sequence is stored in |cur_cs|; otherwise |cur_cs| is set to zero.

Underlying this simple description is a certain amount of complexity
because of all the cases that need to be handled.
However, the inner loop of |get_next| is reasonably short and fast.

When |get_next| is asked to get the next token of a \.{\\read} line,
it sets |cur_cmd=cur_chr=cur_cs=0| in the case that no more tokens
appear on that line. (There might not be any tokens at all, if the
|end_line_char| has |ignore| as its catcode.)

@ The value of |par_loc| is the |eqtb| address of `\.{\\par}'. This quantity
is needed because a blank line of input is supposed to be exactly equivalent
to the appearance of \.{\\par}; we must set |cur_cs:=par_loc|
when detecting a blank line.

@<Glob...@>=
@!par_loc:pointer; {location of `\.{\\par}' in |eqtb|}
@!par_token:halfword; {token representing `\.{\\par}'}

@ @<Put each...@>=
primitive_tex("par",par_end,too_big_char,too_big_char); {cf.\ |scan_file_name|}
@!@:par_}{\.{\\par} primitive@>
par_loc:=cur_val; par_token:=cs_token_flag+par_loc;

@ The function |get_next| is now defined in |textoken.c|. Parts of
this routine are executed more often than any other instructions of \TeX.
@^mastication@>@^inner loop@>

@ The global variable |force_eof| is normally |false|; it is set |true|
by an \.{\\endinput} command. |luacstrings| is the number of lua print
statements waiting to be input, it is changed by |luatokencall|.

|no_expand_flag| is a special character value that is inserted by
|get_next| if it wants to suppress expansion.

@d no_expand_flag==special_char {this characterizes a special variant of |relax|}
@d end_line_char_inactive==(end_line_char<0)or(end_line_char>127)


@<Glob...@>=
@!force_eof:boolean; {should the next \.{\\input} be aborted early?}
@!luacstrings:integer;  {how many lua strings are waiting to be input?}

@ If the user has set the |pausing| parameter to some positive value,
and if nonstop mode has not been selected, each line of input is displayed
on the terminal and the transcript file, followed by `\.{=>}'.
\TeX\ waits for a response. If the response is simply |carriage_return|, the
line is accepted as it stands, otherwise the line typed is
used instead of the line in the file.

@p procedure firm_up_the_line;
var k:0..buf_size; {an index into |buffer|}
begin limit:=last;
if pausing>0 then if interaction>nonstop_mode then
  begin wake_up_terminal; print_ln;
  if start<limit then for k:=start to limit-1 do print(buffer[k]);
  first:=limit; prompt_input("=>"); {wait for user response}
@.=>@>
  if last>first then
    begin for k:=first to last-1 do {move line down in buffer}
      buffer[k+start-first]:=buffer[k];
    limit:=start+last-first;
    end;
  end;
end;

@ Since |get_next| is used so frequently in \TeX, it is convenient
to define three related procedures that do a little more:

\yskip\hang|get_token| not only sets |cur_cmd| and |cur_chr|, it
also sets |cur_tok|, a packed halfword version of the current token.

\yskip\hang|get_x_token|, meaning ``get an expanded token,'' is like
|get_token|, but if the current token turns out to be a user-defined
control sequence (i.e., a macro call), or a conditional,
or something like \.{\\topmark} or \.{\\expandafter} or \.{\\csname},
it is eliminated from the input by beginning the expansion of the macro
or the evaluation of the conditional.

\yskip\hang|x_token| is like |get_x_token| except that it assumes that
|get_next| has already been called.

\yskip\noindent
In fact, these three procedures account for almost every use of |get_next|.

@ No new control sequences will be defined except during a call of
|get_token|, or when \.{\\csname} compresses a token list, because
|no_new_control_sequence| is always |true| at other times.

@p procedure get_token; {sets |cur_cmd|, |cur_chr|, |cur_tok|}
begin no_new_control_sequence:=false; get_filtered_next; no_new_control_sequence:=true;
@^inner loop@>
if cur_cs=0 then cur_tok:=(cur_cmd*string_offset)+cur_chr
else cur_tok:=cs_token_flag+cur_cs;
end;

@* \[25] Expanding the next token.
Only a dozen or so command codes |>max_command| can possibly be returned by
|get_next|; in increasing order, they are |undefined_cs|, |expand_after|,
|no_expand|, |input|, |if_test|, |fi_or_else|, |cs_name|, |convert|, |the|,
|top_bot_mark|, |call|, |long_call|, |outer_call|, |long_outer_call|, and
|end_template|.{\emergencystretch=40pt\par}

@ Sometimes, recursive calls to the following |expand| routine may
cause exhaustion of the run-time calling stack, resulting in
forced execution stops by the operating system. To diminish the chance
of this happening, a counter is used to keep track of the recursion
depth, in conjunction with a constant called |expand_depth|.

Note that this does not catch all possible infinite recursion loops,
just the ones that exhaust the application calling stack. The
actual maximum value of |expand_depth| is outside of our control, but
the initial setting of |100| should be enough to prevent problems.
@^system dependencies@>

@<Global...@>=
expand_depth_count:integer;

@ @<Initialize whatever ...@>=
expand_depth_count:=0;

@ The |expand| subroutine is used when |cur_cmd>max_command|. It removes a
``call'' or a conditional or one of the other special operations just
listed.  It follows that |expand| might invoke itself recursively. In all
cases, |expand| destroys the current token, but it sets things up so that
the next |get_next| will deliver the appropriate next token. The value of
|cur_tok| need not be known when |expand| is called.

Since several of the basic scanning routines communicate via global variables,
their values are saved as local variables of |expand| so that
recursive calls don't invalidate them.
@^recursion@>

@p@t\4@>@<Declare the procedure called |macro_call|@>@;@/
@t\4@>@<Declare the procedure called |insert_relax|@>@;@/
@t\4@>@<Declare \eTeX\ procedures for expanding@>@;@/
procedure@?pass_text; forward;@t\2@>
procedure@?start_input; forward;@t\2@>
procedure@?conditional; forward;@t\2@>
procedure@?get_x_token; forward;@t\2@>
procedure@?conv_toks; forward;@t\2@>
procedure@?ins_the_toks; forward;@t\2@>
procedure expand;
label reswitch;
var t:halfword; {token that is being ``expanded after''}
@!p,@!q,@!r:pointer; {for list manipulation}
@!cur_ptr:pointer; { for a local token list pointer }
@!j:0..buf_size; {index into |buffer|}
@!s:ASCII_code; { a character }
@!cv_backup:integer; {to save the global quantity |cur_val|}
@!cvl_backup,@!radix_backup,@!co_backup:small_number;
  {to save |cur_val_level|, etc.}
@!backup_backup:pointer; {to save |link(backup_head)|}
@!save_scanner_status:small_number; {temporary storage of |scanner_status|}
begin
incr(expand_depth_count);
if expand_depth_count>=expand_depth then overflow("expansion depth",expand_depth);
cv_backup:=cur_val; cvl_backup:=cur_val_level; radix_backup:=radix;
co_backup:=cur_order; backup_backup:=link(backup_head);
reswitch:
if cur_cmd<call then @<Expand a nonmacro@>
else if cur_cmd<end_template then macro_call
else @<Insert a token containing |frozen_endv|@>;
cur_val:=cv_backup; cur_val_level:=cvl_backup; radix:=radix_backup;
cur_order:=co_backup; link(backup_head):=backup_backup;
decr(expand_depth_count);
end;

@ @<Glob...@>=
@!is_in_csname: boolean;

@ @<Set init...@>=
is_in_csname := false;

@ @<Expand a nonmacro@>=
begin if tracing_commands>1 then show_cur_cmd_chr;
case cur_cmd of
top_bot_mark:@<Insert the \(a)appropriate mark text into the scanner@>;
expand_after:if cur_chr=0 then @<Expand the token after the next token@>
  else @<Negate a boolean conditional and |goto reswitch|@>;
no_expand: if cur_chr=0 then @<Suppress expansion of the next token@>
  else @<Implement \.{\\primitive}@>;
cs_name:@<Manufacture a control sequence name@>;
convert:conv_toks; {this procedure is discussed in Part 27 below}
the:ins_the_toks; {this procedure is discussed in Part 27 below}
if_test:conditional; {this procedure is discussed in Part 28 below}
fi_or_else:@<Terminate the current conditional and skip to \.{\\fi}@>;
input:@<Initiate or terminate input from a file@>;
othercases @<Complain about an undefined macro@>
endcases;
end

@ It takes only a little shuffling to do what \TeX\ calls \.{\\expandafter}.

@<Expand the token after...@>=
begin get_token; t:=cur_tok; get_token;
if cur_cmd>max_command then expand@+else back_input;
cur_tok:=t; back_input;
end

@ The implementation of \.{\\noexpand} is a bit trickier, because it is
necessary to insert a special `|dont_expand|' marker into \TeX's reading
mechanism.  This special marker is processed by |get_next|, but it does
not slow down the inner loop.

Since \.{\\outer} macros might arise here, we must also
clear the |scanner_status| temporarily.

@<Suppress expansion...@>=
begin save_scanner_status:=scanner_status; scanner_status:=normal;
get_token; scanner_status:=save_scanner_status; t:=cur_tok;
back_input; {now |start| and |loc| point to the backed-up token |t|}
if t>=cs_token_flag then
  begin p:=get_avail; info(p):=cs_token_flag+frozen_dont_expand;
  link(p):=loc; start:=p; loc:=p;
  end;
end

@ The \.{\\primitive} handling. If the primitive meaning of the next
token is an expandable command, it suffices to replace the current
token with the primitive one and restart |expand|.

Otherwise, the token we just read has to be pushed back, as well
as a token matching the internal form of \.{\\primitive}, that is
sneaked in as an alternate form of |ignore_spaces|.
@!@:primitive_}{\.{\\primitive} primitive (internalized)@>

An implementation problem surfaces: There really is no |cur_cs|
attached to the inserted primitive command, so it is safer to set
|cur_cs| to zero.  |cur_tok| has a similar problem. And for the
non-expanded branch, simply pushing back a token that matches the
correct internal command does not work, because that approach would
not survive roundtripping to a temporary file or even a token list.

In a next version, it would be smart to create |frozen_| versions of
all the primitives.  Then, this problem would not happen, at the
expense of a few hundred extra control sequences.

@<Implement \.{\\primitive}@>=
begin save_scanner_status := scanner_status; scanner_status:=normal;
get_token; scanner_status:=save_scanner_status;
cur_cs := prim_lookup(text(cur_cs));
if cur_cs<>undefined_primitive then begin
  t:=get_prim_eq_type(cur_cs);
  if t>max_command then begin
    cur_cmd := t;
    cur_chr := get_prim_equiv(cur_cs);
    cur_tok := (cur_cmd*string_offset)+cur_chr;
    cur_cs  := 0;
    goto reswitch;
    end
  else begin
    back_input; { now |loc| and |start| point to a one-item list }
    p:=get_avail; info(p):=cs_token_flag+frozen_primitive;
    link(p):=loc; loc:=p; start:=p;
    end;
  end
else begin
  print_err("Missing primitive name");
  help2("The control sequence marked <to be read again> does not")@/
    ("represent any known primitive.");
  back_error;
  end;
end


@ This block deals with unexpandable \.{\\primitive} appearing at a spot where
an integer or an internal values should have been found. It fetches the
next token then resets |cur_cmd|, |cur_cs|, and |cur_tok|, based on the
primitive value of that token. No expansion takes place, because the
next token may be all sorts of things. This could trigger further
expansion creating new errors.

@<Reset |cur_tok| for unexpandable primitives, goto restart @>=
begin
get_token;
cur_cs := prim_lookup(text(cur_cs));
if cur_cs<>undefined_primitive then begin
  cur_cmd := get_prim_eq_type(cur_cs);
  cur_chr := get_prim_equiv(cur_cs);
  cur_tok := (cur_cmd*string_offset)+cur_chr;
  end
else begin
  cur_cmd := relax;
  cur_chr := 0;
  cur_tok := cs_token_flag+frozen_relax;
  cur_cs  := frozen_relax;
  end;
goto restart;
end

@ @<Complain about an undefined macro@>=
begin print_err("Undefined control sequence");
@.Undefined control sequence@>
help5("The control sequence at the end of the top line")@/
("of your error message was never \def'ed. If you have")@/
("misspelled it (e.g., `\hobx'), type `I' and the correct")@/
("spelling (e.g., `I\hbox'). Otherwise just continue,")@/
("and I'll forget about whatever was undefined.");
error;
end

@ The |expand| procedure and some other routines that construct token
lists find it convenient to use the following macros, which are valid only if
the variables |p| and |q| are reserved for token-list building.

@d store_new_token(#)==begin q:=get_avail; link(p):=q; info(q):=#;
  p:=q; {|link(p)| is |null|}
  end
@d fast_store_new_token(#)==begin fast_get_avail(q); link(p):=q; info(q):=#;
  p:=q; {|link(p)| is |null|}
  end

@ @<Manufacture a control...@>=
begin r:=get_avail; p:=r; {head of the list of characters}
is_in_csname := true;
repeat get_x_token;
if cur_cs=0 then store_new_token(cur_tok);
until cur_cs<>0;
if cur_cmd<>end_cs_name then @<Complain about missing \.{\\endcsname}@>;
is_in_csname := false;
@<Look up the characters of list |r| in the hash table, and set |cur_cs|@>;
flush_list(r);
if eq_type(cur_cs)=undefined_cs then
  begin eq_define(cur_cs,relax,too_big_char); {N.B.: The |save_stack| might change}
  end; {the control sequence will now match `\.{\\relax}'}
cur_tok:=cur_cs+cs_token_flag; back_input;
end

@ @<Complain about missing \.{\\endcsname}@>=
begin print_err("Missing "); print_esc("endcsname"); print(" inserted");
@.Missing \\endcsname...@>
help2("The control sequence marked <to be read again> should")@/
  ("not appear between \csname and \endcsname.");
back_error;
end

@ @<Look up the characters of list |r| in the hash table...@>=
j:=first; p:=link(r);
while p<>null do
  begin if j>=max_buf_stack then
    begin max_buf_stack:=j+4;
    if max_buf_stack=buf_size then
      check_buffer_overflow(max_buf_stack);
@:TeX capacity exceeded buffer size}{\quad buffer size@>
    end;
  s := info(p) mod string_offset;
  if s <= @"7F then begin
    buffer[j]:=s; incr(j);
    end
  else if s<=@"7FF then begin
    buffer[j]:=@"C0 + s div @"40; incr(j);
    buffer[j]:=@"80 + s mod @"40; incr(j);
    end
  else if s<=@"FFFF then begin
    buffer[j]:=@"E0 + s div @"1000; incr(j);
    buffer[j]:=@"80 + (s mod @"1000) div @"40; incr(j);
    buffer[j]:=@"80 + (s mod @"1000) mod @"40; incr(j);
    end
  else begin
    buffer[j]:=@"F0 + s div @"40000;  incr(j);
    buffer[j]:=@"80 + (s mod @"40000) div @"1000;  incr(j);
    buffer[j]:=@"80 + ((s mod @"40000) mod @"1000) div @"40;  incr(j);
    buffer[j]:=@"80 + ((s mod @"40000) mod @"1000) mod @"40;  incr(j);
    end;
  p:=link(p);
  end;
if j>first then
  begin no_new_control_sequence:=false; cur_cs:=id_lookup(first,j-first);
  no_new_control_sequence:=true;
  end
else if j=first then cur_cs:=null_cs {the list is empty}

@ An |end_template| command is effectively changed to an |endv| command
by the following code. (The reason for this is discussed below; the
|frozen_end_template| at the end of the template has passed the
|check_outer_validity| test, so its mission of error detection has been
accomplished.)

@<Insert a token containing |frozen_endv|@>=
begin cur_tok:=cs_token_flag+frozen_endv; back_input;
end

@ The processing of \.{\\input} involves the |start_input| subroutine,
which will be declared later; the processing of \.{\\endinput} is trivial.

@<Put each...@>=
primitive_tex("input",input,0,0);@/
@!@:input_}{\.{\\input} primitive@>
primitive_tex("endinput",input,1,0);@/
@!@:end_input_}{\.{\\endinput} primitive@>

@ @<Initiate or terminate input...@>=
if cur_chr=1 then force_eof:=true
@/@<Cases for |input|@>@/
else if name_in_progress then insert_relax
else start_input

@ Sometimes the expansion looks too far ahead, so we want to insert
a harmless \.{\\relax} into the user's input.

@<Declare the procedure called |insert_relax|@>=
procedure insert_relax;
begin cur_tok:=cs_token_flag+cur_cs; back_input;
cur_tok:=cs_token_flag+frozen_relax; back_input; token_type:=inserted;
end;

@ Here is a recursive procedure that is \TeX's usual way to get the
next token of input. It has been slightly optimized to take account of
common cases.

@p procedure get_x_token; {sets |cur_cmd|, |cur_chr|, |cur_tok|,
  and expands macros}
label restart,done;
begin restart: get_filtered_next;
@^inner loop@>
if cur_cmd<=max_command then goto done;
if cur_cmd>=call then
  if cur_cmd<end_template then macro_call
  else  begin cur_cs:=frozen_endv; cur_cmd:=endv;
    goto done; {|cur_chr=null_list|}
    end
else expand;
goto restart;
done: if cur_cs=0 then cur_tok:=(cur_cmd*string_offset)+cur_chr
else cur_tok:=cs_token_flag+cur_cs;
end;

@ The |get_x_token| procedure is equivalent to two consecutive
procedure calls: |get_next; x_token|.

@p procedure x_token; {|get_x_token| without the initial |get_next|}
begin while cur_cmd>max_command do
  begin expand;
  get_filtered_next;
  end;
if cur_cs=0 then cur_tok:=(cur_cmd*string_offset)+cur_chr
else cur_tok:=cs_token_flag+cur_cs;
end;

@ The |get_filtered_next| procedure allows Lua code to mutate the
output of |get_next| before \TeX\ looks at it. The implementation
is in the C file |luatoken.c|.

@d get_filtered_next==get_token_lua



@ A control sequence that has been \.{\\def}'ed by the user is expanded by
\TeX's |macro_call| procedure.

Before we get into the details of |macro_call|, however, let's consider the
treatment of primitives like \.{\\topmark}, since they are essentially
macros without parameters. The token lists for such marks are kept in five
global arrays of pointers; we refer to the individual entries of these
arrays by symbolic macros |top_mark|, etc. The value of |top_mark(x)|, etc.
is either |null| or a pointer to the reference count of a token list.

The variable |biggest_used_mark| is an aid to try and keep the code
somehwat efficient without too much extra work: it registers the
highest mark class ever instantiated by the user, so the loops
in |fire_up| and |vsplit| do not have to traverse the full range
|0..biggest_mark|.

@d top_mark_code=0 {the mark in effect at the previous page break}
@d first_mark_code=1 {the first mark between |top_mark| and |bot_mark|}
@d bot_mark_code=2 {the mark in effect at the current page break}
@d split_first_mark_code=3 {the first mark found by \.{\\vsplit}}
@d split_bot_mark_code=4 {the last mark found by \.{\\vsplit}}
@#
@d top_mark(#)==top_marks_array[#]
@d first_mark(#)==first_marks_array[#]
@d bot_mark(#)==bot_marks_array[#]
@d split_first_mark(#)==split_first_marks_array[#]
@d split_bot_mark(#)==split_bot_marks_array[#]
@#
@d delete_top_mark(#)==begin if top_mark(#)<>null then
      delete_token_ref(top_mark(#)); top_mark(#):=null; end
@d delete_bot_mark(#)==begin if bot_mark(#)<>null then
      delete_token_ref(bot_mark(#)); bot_mark(#):=null; end
@d delete_first_mark(#)==begin if first_mark(#)<>null then
      delete_token_ref(first_mark(#)); first_mark(#):=null; end
@d delete_split_first_mark(#)==begin if split_first_mark(#)<>null then
      delete_token_ref(split_first_mark(#)); split_first_mark(#):=null; end
@d delete_split_bot_mark(#)==begin if split_bot_mark(#)<>null then
      delete_token_ref(split_bot_mark(#)); split_bot_mark(#):=null; end
@#
@d clear_marks_code=1
@d marks_code=5
@#

@<Glob...@>=
@!top_marks_array:array[0..biggest_mark] of pointer;
@!first_marks_array:array[0..biggest_mark] of pointer;
@!bot_marks_array:array[0..biggest_mark] of pointer;
@!split_first_marks_array:array[0..biggest_mark] of pointer;
@!split_bot_marks_array:array[0..biggest_mark] of pointer;
biggest_used_mark:halfword;

@ @<Set init...@>=
biggest_used_mark:=0;
for i:=0 to biggest_mark do begin
  top_mark(i):=null;
  first_mark(i):=null;
  bot_mark(i):=null;
  split_first_mark(i):=null;
  split_bot_mark(i):=null;
end;

@ @<Put each...@>=
primitive_tex("topmark",top_bot_mark,top_mark_code,0);
@!@:top_mark_}{\.{\\topmark} primitive@>
primitive_tex("firstmark",top_bot_mark,first_mark_code,0);
@!@:first_mark_}{\.{\\firstmark} primitive@>
primitive_tex("botmark",top_bot_mark,bot_mark_code,0);
@!@:bot_mark_}{\.{\\botmark} primitive@>
primitive_tex("splitfirstmark",top_bot_mark,split_first_mark_code,0);
@!@:split_first_mark_}{\.{\\splitfirstmark} primitive@>
primitive_tex("splitbotmark",top_bot_mark,split_bot_mark_code,0);
@!@:split_bot_mark_}{\.{\\splitbotmark} primitive@>
primitive_luatex("clearmarks",mark,clear_marks_code,0);@/
@!@:clearmarks_}{\.{\\clearmarks} primitive@>
primitive_etex("marks",mark,marks_code,0);
@!@:marks_}{\.{\\marks} primitive@>
primitive_etex("topmarks",top_bot_mark,top_mark_code+marks_code,0);
@!@:top_marks_}{\.{\\topmarks} primitive@>
primitive_etex("firstmarks",top_bot_mark,first_mark_code+marks_code,0);
@!@:first_marks_}{\.{\\firstmarks} primitive@>
primitive_etex("botmarks",top_bot_mark,bot_mark_code+marks_code,0);
@!@:bot_marks_}{\.{\\botmarks} primitive@>
primitive_etex("splitfirstmarks",top_bot_mark,split_first_mark_code+marks_code,0);
@!@:split_first_marks_}{\.{\\splitfirstmarks} primitive@>
primitive_etex("splitbotmarks",top_bot_mark,split_bot_mark_code+marks_code,0);
@!@:split_bot_marks_}{\.{\\splitbotmarks} primitive@>

@ The following code is activated when |cur_cmd=top_bot_mark| and
when |cur_chr| is a code like |top_mark_code|.

@<Insert the \(a)appropriate mark text into the scanner@>=
begin t:=cur_chr mod marks_code;
if cur_chr>=marks_code then scan_mark_num@+else cur_val:=0;
case t of
  first_mark_code:       cur_ptr:=first_mark(cur_val);
  bot_mark_code:         cur_ptr:=bot_mark(cur_val);
  split_first_mark_code: cur_ptr:=split_first_mark(cur_val);
  split_bot_mark_code:   cur_ptr:=split_bot_mark(cur_val);
  othercases             cur_ptr:=top_mark(cur_val)
endcases;
if cur_ptr<>null then begin_token_list(cur_ptr,mark_text);
end

@ Now let's consider |macro_call| itself, which is invoked when \TeX\ is
scanning a control sequence whose |cur_cmd| is either |call|, |long_call|,
|outer_call|, or |long_outer_call|.  The control sequence definition
appears in the token list whose reference count is in location |cur_chr|
of |mem|.

The global variable |long_state| will be set to |call| or to |long_call|,
depending on whether or not the control sequence disallows \.{\\par}
in its parameters. The |get_next| routine will set |long_state| to
|outer_call| and emit \.{\\par}, if a file ends or if an \.{\\outer}
control sequence occurs in the midst of an argument.

@<Glob...@>=
@!long_state:call..long_outer_call; {governs the acceptance of \.{\\par}}

@ The parameters, if any, must be scanned before the macro is expanded.
Parameters are token lists without reference counts. They are placed on
an auxiliary stack called |pstack| while they are being scanned, since
the |param_stack| may be losing entries during the matching process.
(Note that |param_stack| can't be gaining entries, since |macro_call| is
the only routine that puts anything onto |param_stack|, and it
is not recursive.)

@<Glob...@>=
@!pstack:array[0..8] of pointer; {arguments supplied to a macro}

@ After parameter scanning is complete, the parameters are moved to the
|param_stack|. Then the macro body is fed to the scanner; in other words,
|macro_call| places the defined text of the control sequence at the
top of\/ \TeX's input stack, so that |get_next| will proceed to read it
next.

The global variable |cur_cs| contains the |eqtb| address of the control sequence
being expanded, when |macro_call| begins. If this control sequence has not been
declared \.{\\long}, i.e., if its command code in the |eq_type| field is
not |long_call| or |long_outer_call|, its parameters are not allowed to contain
the control sequence \.{\\par}. If an illegal \.{\\par} appears, the macro
call is aborted, and the \.{\\par} will be rescanned.

@<Declare the procedure called |macro_call|@>=
procedure macro_call; {invokes a user-defined control sequence}
label exit, continue, done, done1, found;
var r:pointer; {current node in the macro's token list}
@!p:pointer; {current node in parameter token list being built}
@!q:pointer; {new node being put into the token list}
@!s:pointer; {backup pointer for parameter matching}
@!t:pointer; {cycle pointer for backup recovery}
@!u,@!v:pointer; {auxiliary pointers for backup recovery}
@!rbrace_ptr:pointer; {one step before the last |right_brace| token}
@!n:small_number; {the number of parameters scanned}
@!unbalance:halfword; {unmatched left braces in current parameter}
@!m:halfword; {the number of tokens or groups (usually)}
@!ref_count:pointer; {start of the token list}
@!save_scanner_status:small_number; {|scanner_status| upon entry}
@!save_warning_index:pointer; {|warning_index| upon entry}
@!match_chr:ASCII_code; {character used in parameter}
begin save_scanner_status:=scanner_status; save_warning_index:=warning_index;
warning_index:=cur_cs; ref_count:=cur_chr; r:=link(ref_count); n:=0;
p:=null; m:=0; rbrace_ptr:=null; match_chr:=0;
if tracing_macros>0 then @<Show the text of the macro being expanded@>;
if info(r)=protected_token then r:=link(r);
if info(r)<>end_match_token then
  @<Scan the parameters and make |link(r)| point to the macro body; but
    |return| if an illegal \.{\\par} is detected@>;
@<Feed the macro body and its parameters to the scanner@>;
exit:scanner_status:=save_scanner_status; warning_index:=save_warning_index;
end;

@ Before we put a new token list on the input stack, it is wise to clean off
all token lists that have recently been depleted. Then a user macro that ends
with a call to itself will not require unbounded stack space.

@<Feed the macro body and its parameters to the scanner@>=
while (state=token_list)and(loc=null)and(token_type<>v_template) do
  end_token_list; {conserve stack space}
begin_token_list(ref_count,macro); name:=warning_index; loc:=link(r);
if n>0 then
  begin if param_ptr+n>max_param_stack then
    begin max_param_stack:=param_ptr+n;
    if max_param_stack>param_size then
      overflow("parameter stack size",param_size);
@:TeX capacity exceeded parameter stack size}{\quad parameter stack size@>
    end;
  for m:=0 to n-1 do param_stack[param_ptr+m]:=pstack[m];
  param_ptr:=param_ptr+n;
  end

@ At this point, the reader will find it advisable to review the explanation
of token list format that was presented earlier, since many aspects of that
format are of importance chiefly in the |macro_call| routine.

The token list might begin with a string of compulsory tokens before the
first |match| or |end_match|. In that case the macro name is supposed to be
followed by those tokens; the following program will set |s=null| to
represent this restriction. Otherwise |s| will be set to the first token of
a string that will delimit the next parameter.

@<Scan the parameters and make |link(r)| point to the macro body...@>=
begin scanner_status:=matching; unbalance:=0;
long_state:=eq_type(cur_cs);
if long_state>=outer_call then long_state:=long_state-2;
repeat link(temp_token_head):=null;
if (info(r)>=end_match_token)or(info(r)<match_token) then s:=null
else  begin match_chr:=info(r)-match_token; s:=link(r); r:=s;
  p:=temp_token_head; m:=0;
  end;
@<Scan a parameter until its delimiter string has been found; or, if |s=null|,
  simply scan the delimiter string@>;@/
{now |info(r)| is a token whose command code is either |match| or |end_match|}
until info(r)=end_match_token;
end

@ If |info(r)| is a |match| or |end_match| command, it cannot be equal to
any token found by |get_token|. Therefore an undelimited parameter---i.e.,
a |match| that is immediately followed by |match| or |end_match|---will
always fail the test `|cur_tok=info(r)|' in the following algorithm.

@<Scan a parameter until its delimiter string has been found; or, ...@>=
continue: get_token; {set |cur_tok| to the next token of input}
if cur_tok=info(r) then
  @<Advance \(r)|r|; |goto found| if the parameter delimiter has been
    fully matched, otherwise |goto continue|@>;
@<Contribute the recently matched tokens to the current parameter, and
  |goto continue| if a partial match is still in effect;
  but abort if |s=null|@>;
if cur_tok=par_token then if long_state<>long_call then
  if not suppress_long_error then
    @<Report a runaway argument and abort@>;
if cur_tok<right_brace_limit then
  if cur_tok<left_brace_limit then
    @<Contribute an entire group to the current parameter@>
  else @<Report an extra right brace and |goto continue|@>
else @<Store the current token, but |goto continue| if it is
   a blank space that would become an undelimited parameter@>;
incr(m);
if info(r)>end_match_token then goto continue;
if info(r)<match_token then goto continue;
found: if s<>null then @<Tidy up the parameter just scanned, and tuck it away@>

@ @<Store the current token, but |goto continue| if it is...@>=
begin if cur_tok=space_token then
  if info(r)<=end_match_token then
    if info(r)>=match_token then goto continue;
store_new_token(cur_tok);
end

@ A slightly subtle point arises here: When the parameter delimiter ends
with `\.{\#\{}', the token list will have a left brace both before and
after the |end_match|\kern-.4pt. Only one of these should affect the
|align_state|, but both will be scanned, so we must make a correction.

@<Advance \(r)|r|; |goto found| if the parameter delimiter has been fully...@>=
begin r:=link(r);
if (info(r)>=match_token)and(info(r)<=end_match_token) then
  begin if cur_tok<left_brace_limit then decr(align_state);
  goto found;
  end
else goto continue;
end

@ @<Report an extra right brace and |goto continue|@>=
begin back_input; print_err("Argument of "); sprint_cs(warning_index);
@.Argument of \\x has...@>
print(" has an extra }");
help6("I've run across a `}' that doesn't seem to match anything.")@/
  ("For example, `\def\a#1{...}' and `\a}' would produce")@/
  ("this error. If you simply proceed now, the `\par' that")@/
  ("I've just inserted will cause me to report a runaway")@/
  ("argument that might be the root of the problem. But if")@/
  ("your `}' was spurious, just type `2' and it will go away.");
incr(align_state); long_state:=call; cur_tok:=par_token; ins_error;
goto continue;
end {a white lie; the \.{\\par} won't always trigger a runaway}

@ If |long_state=outer_call|, a runaway argument has already been reported.

@<Report a runaway argument and abort@>=
begin if long_state=call then
  begin runaway; print_err("Paragraph ended before ");
@.Paragraph ended before...@>
  sprint_cs(warning_index); print(" was complete");
  help3("I suspect you've forgotten a `}', causing me to apply this")@/
    ("control sequence to too much text. How can we recover?")@/
    ("My plan is to forget the whole thing and hope for the best.");
  back_error;
  end;
pstack[n]:=link(temp_token_head); align_state:=align_state-unbalance;
for m:=0 to n do flush_list(pstack[m]);
return;
end

@ When the following code becomes active, we have matched tokens from |s| to
the predecessor of |r|, and we have found that |cur_tok<>info(r)|. An
interesting situation now presents itself: If the parameter is to be
delimited by a string such as `\.{ab}', and if we have scanned `\.{aa}',
we want to contribute one `\.a' to the current parameter and resume
looking for a `\.b'. The program must account for such partial matches and
for others that can be quite complex.  But most of the time we have |s=r|
and nothing needs to be done.

Incidentally, it is possible for \.{\\par} tokens to sneak in to certain
parameters of non-\.{\\long} macros. For example, consider a case like
`\.{\\def\\a\#1\\par!\{...\}}' where the first \.{\\par} is not followed
by an exclamation point. In such situations it does not seem appropriate
to prohibit the \.{\\par}, so \TeX\ keeps quiet about this bending of
the rules.

@<Contribute the recently matched tokens to the current parameter...@>=
if s<>r then begin
  if s=null then @<Report an improper use of the macro and abort@>
  else  begin t:=s;
    repeat store_new_token(info(t)); incr(m); u:=link(t); v:=s;
    loop@+  begin if u=r then begin
        if cur_tok<>info(v) then goto done
        else  begin r:=link(v); goto continue;
          end;
        end;
      if info(u)<>info(v) then goto done;
      u:=link(u); v:=link(v);
      end;
    done: t:=link(t);
    until t=r;
    r:=s; {at this point, no tokens are recently matched}
    end;
  end

@ @<Report an improper use...@>=
begin print_err("Use of "); sprint_cs(warning_index);
@.Use of x doesn't match...@>
print(" doesn't match its definition");
help4("If you say, e.g., `\def\a1{...}', then you must always")@/
  ("put `1' after `\a', since control sequence names are")@/
  ("made up of letters only. The macro here has not been")@/
  ("followed by the required stuff, so I'm ignoring it.");
error; return;
end

@ @<Contribute an entire group to the current parameter@>=
begin unbalance:=1;
@^inner loop@>
loop@+  begin fast_store_new_token(cur_tok); get_token;
  if cur_tok=par_token then if long_state<>long_call then
    if not suppress_long_error then
      @<Report a runaway argument and abort@>;
  if cur_tok<right_brace_limit then begin
    if cur_tok<left_brace_limit then incr(unbalance)
    else  begin decr(unbalance);
      if unbalance=0 then goto done1;
      end;
    end;
  end;
done1: rbrace_ptr:=p; store_new_token(cur_tok);
end

@ If the parameter consists of a single group enclosed in braces, we must
strip off the enclosing braces. That's why |rbrace_ptr| was introduced.

@<Tidy up the parameter just scanned, and tuck it away@>=
begin if (m=1)and(info(p)<right_brace_limit)and(p<>temp_token_head) then
  begin link(rbrace_ptr):=null; free_avail(p);
  p:=link(temp_token_head); pstack[n]:=link(p); free_avail(p);
  end
else pstack[n]:=link(temp_token_head);
incr(n);
if tracing_macros>0 then
  begin begin_diagnostic; print_nl(match_chr); print_int(n);
  print("<-"); show_token_list(pstack[n-1],null,1000);
  end_diagnostic(false);
  end;
end

@ @<Show the text of the macro being expanded@>=
begin begin_diagnostic; print_ln; print_cs(warning_index);
token_show(ref_count); end_diagnostic(false);
end

@* \[26] Basic scanning subroutines.
Let's turn now to some procedures that \TeX\ calls upon frequently to digest
certain kinds of patterns in the input. Most of these are quite simple;
some are quite elaborate. Almost all of the routines call |get_x_token|,
which can cause them to be invoked recursively.
@^stomach@>
@^recursion@>

@ The |scan_left_brace| routine is called when a left brace is supposed to be
the next non-blank token. (The term ``left brace'' means, more precisely,
a character whose catcode is |left_brace|.) \TeX\ allows \.{\\relax} to
appear before the |left_brace|.

@p procedure scan_left_brace; {reads a mandatory |left_brace|}
begin @<Get the next non-blank non-relax non-call token@>;
if cur_cmd<>left_brace then
  begin print_err("Missing { inserted");
@.Missing \{ inserted@>
  help4("A left brace was mandatory here, so I've put one in.")@/
    ("You might want to delete and/or insert some corrections")@/
    ("so that I will find a matching right brace soon.")@/
    ("(If you're confused by all this, try typing `I}' now.)");
  back_error; cur_tok:=left_brace_token+"{"; cur_cmd:=left_brace;
  cur_chr:="{"; incr(align_state);
  end;
end;

@ @<Get the next non-blank non-relax non-call token@>=
repeat get_x_token;
until (cur_cmd<>spacer)and(cur_cmd<>relax)

@ The |scan_optional_equals| routine looks for an optional `\.=' sign preceded
by optional spaces; `\.{\\relax}' is not ignored here.

@p procedure scan_optional_equals;
begin  @<Get the next non-blank non-call token@>;
if cur_tok<>other_token+"=" then back_input;
end;

@ @<Get the next non-blank non-call token@>=
repeat get_x_token;
until cur_cmd<>spacer

@ Here is a procedure that sounds an alarm when mu and non-mu units
are being switched.

@p procedure mu_error;
begin print_err("Incompatible glue units");
@.Incompatible glue units@>
help1("I'm going to assume that 1mu=1pt when they're mixed.");
error;
end;

@ The next routine `|scan_something_internal|' is used to fetch internal
numeric quantities like `\.{\\hsize}', and also to handle the `\.{\\the}'
when expanding constructions like `\.{\\the\\toks0}' and
`\.{\\the\\baselineskip}'. Soon we will be considering the |scan_int|
procedure, which calls |scan_something_internal|; on the other hand,
|scan_something_internal| also calls |scan_int|, for constructions like
`\.{\\catcode\`\\\$}' or `\.{\\fontdimen} \.3 \.{\\ff}'. So we
have to declare |scan_int| as a |forward| procedure. A few other
procedures are also declared at this point.

@p procedure@?scan_int; forward; {scans an integer value}
@t\4\4@>@<Declare procedures that scan restricted classes of integers@>@;
@t\4\4@>@<Declare \eTeX\ procedures for scanning@>@;
@t\4\4@>@<Declare procedures that scan font-related stuff@>
@t\4\4@>@<Declare procedures that scan ocp-related stuff@>

@ \TeX\ doesn't know exactly what to expect when
|scan_something_internal| begins.  For example, an integer or
dimension or glue value could occur immediately after `\.{\\hskip}';
and one can even say \.{\\the} with respect to token lists in
constructions like `\.{\\xdef\\o\{\\the\\output\}}'.  On the other
hand, only integers are allowed after a construction like
`\.{\\count}'. To handle the various possibilities,
|scan_something_internal| has a |level| parameter, which tells the
``highest'' kind of quantity that |scan_something_internal| is allowed
to produce. Eight levels are distinguished, namely |int_val|,
|attr_val|, |dimen_val|, |glue_val|, |mu_val|, |dir_val|, |ident_val|,
and |tok_val|.

The output of |scan_something_internal| (and of the other routines
|scan_int|, |scan_dimen|, and |scan_glue| below) is put into the global
variable |cur_val|, and its level is put into |cur_val_level|. The highest
values of |cur_val_level| are special: |mu_val| is used only when
|cur_val| points to something in a ``muskip'' register, or to one of the
three parameters \.{\\thinmuskip}, \.{\\medmuskip}, \.{\\thickmuskip};
|ident_val| is used only when |cur_val| points to a font identifier;
|tok_val| is used only when |cur_val| points to |null| or to the reference
count of a token list. The last two cases are allowed only when
|scan_something_internal| is called with |level=tok_val|.

If the output is glue, |cur_val| will point to a glue specification, and
the reference count of that glue will have been updated to reflect this
reference; if the output is a nonempty token list, |cur_val| will point to
its reference count, but in this case the count will not have been updated.
Otherwise |cur_val| will contain the integer or scaled value in question.

@d int_val=0 {integer values}
@d attr_val=1 {integer values}
@d dimen_val=2 {dimension values}
@d glue_val=3 {glue specifications}
@d mu_val=4 {math glue specifications}
@d dir_val=5 {directions}
@d ident_val=6 {font identifier}
@d tok_val=7 {token lists}

@<Glob...@>=
@!cur_val:integer; {value returned by numeric scanners}
@!cur_val1:integer; {delcodes are now 51 digits}
@!cur_val_level:int_val..tok_val; {the ``level'' of this value}

@ The hash table is initialized with `\.{\\count}', `\.{\\attribute}',
`\.{\\dimen}', `\.{\\skip}', and `\.{\\muskip}' all having |register|
as their command code; they are distinguished by the |chr_code|, which
is either |int_val|, |attr_val|, |dimen_val|, |glue_val|, or |mu_val|.

@<Put each...@>=
primitive_tex("count",register,int_val,0);
@!@:count_}{\.{\\count} primitive@>
primitive_luatex("attribute",register,attr_val,0);
@!@:count_}{\.{\\attribute} primitive@>
primitive_tex("dimen",register,dimen_val,0);
@!@:dimen_}{\.{\\dimen} primitive@>
primitive_tex("skip",register,glue_val,0);
@!@:skip_}{\.{\\skip} primitive@>
primitive_tex("muskip",register,mu_val,0);

@ OK, we're ready for |scan_something_internal| itself. A second parameter,
|negative|, is set |true| if the value that is found should be negated.
It is assumed that |cur_cmd| and |cur_chr| represent the first token of
the internal quantity to be scanned; an error will be signalled if
|cur_cmd<min_internal| or |cur_cmd>max_internal|.

@d scanned_result_end(#)==cur_val_level:=#;@+end
@d scanned_result(#)==@+begin cur_val:=#;scanned_result_end

@p procedure scan_something_internal(@!level:small_number;@!negative:boolean);
  {fetch an internal parameter}
label exit, restart;
var m:halfword; {|chr_code| part of the operand token}
    n, k: integer; {accumulators}
@!q:halfword; {general purpose index}
@!p:0..nest_size; {index into |nest|}
begin restart: m:=cur_chr;
case cur_cmd of
def_char_code: @<Fetch a character code from some table@>;
def_del_code: @<Fetch a character code from some table@>;
extdef_math_code: @<Fetch an ext character code from some table@>;
extdef_del_code: @<Fetch an ext character code from some table@>;
toks_register,assign_toks,set_font,def_font,letterspace_font,pdf_copy_font:
  @<Fetch a token list or font identifier, provided that |level=tok_val|@>;
def_family:
  @<Fetch a math font identifier@>;
set_math_param:
  @<Fetch a math param@>;
assign_int: scanned_result(eqtb[m].int)(int_val);
assign_attr: scanned_result(eqtb[m].int)(int_val);
assign_box_dir: begin
  scan_register_num;
  m:=cur_val;
  if box(m)<>null then cur_val:=box_dir(box(m))
  else cur_val:=0;
  cur_val_level:=dir_val;
  end;
assign_dir: scanned_result(eqtb[m].int)(dir_val);
assign_dimen: scanned_result(eqtb[m].sc)(dimen_val);
assign_glue: scanned_result(equiv(m))(glue_val);
assign_mu_glue: scanned_result(equiv(m))(mu_val);
math_style: scanned_result(m)(int_val);
set_aux: @<Fetch the |space_factor| or the |prev_depth|@>;
set_prev_graf: @<Fetch the |prev_graf|@>;
set_page_int:@<Fetch the |dead_cycles| or the |insert_penalties|@>;
set_page_dimen: @<Fetch something on the |page_so_far|@>;
set_tex_shape: @<Fetch the |par_shape| size@>;
set_etex_shape: @<Fetch a penalties array element@>;
set_box_dimen: @<Fetch a box dimension@>;
char_given,math_given,omath_given,xmath_given: scanned_result(cur_chr)(int_val);
assign_font_dimen: @<Fetch a font dimension@>;
assign_font_int: @<Fetch a font integer@>;
register: @<Fetch a register@>;
last_item: @<Fetch an item in the current node, if appropriate@>;
ignore_spaces: {trap unexpandable primitives}
  if cur_chr=1 then @<Reset |cur_tok| for unexpandable primitives, goto restart@>;
othercases @<Complain that \.{\\the} can't do this; give zero result@>
endcases;@/
while cur_val_level>level do @<Convert \(c)|cur_val| to a lower level@>;
@<Fix the reference count, if any, and negate |cur_val| if |negative|@>;
exit:end;

procedure scan_something_simple(@!cmd:halfword;@!subitem:halfword);
  {fetch an internal parameter}
label exit;
var m:halfword; {|chr_code| part of the operand token}
@!q:halfword; {general purpose index}
@!p:0..nest_size; {index into |nest|}
@!level:small_number; { allowed level}
@!negative:boolean;
@!save_cur_chr:integer;
begin m:=subitem; level:=tok_val;
negative:=false; {never actually used, added for etexs |last_item| cases}
case cmd of
assign_toks: scanned_result(equiv(m))(tok_val);
assign_int: scanned_result(eqtb[m].int)(int_val);
assign_attr: scanned_result(eqtb[m].int)(int_val);
assign_dir: scanned_result(eqtb[m].int)(dir_val);
assign_dimen: scanned_result(eqtb[m].sc)(dimen_val);
assign_glue: scanned_result(equiv(m))(glue_val);
assign_mu_glue: scanned_result(equiv(m))(mu_val);
math_style: scanned_result(m)(int_val);
set_aux: @<Fetch the |space_factor| or the |prev_depth|@>;
set_prev_graf: @<Fetch the |prev_graf|@>;
set_page_int:@<Fetch the |dead_cycles| or the |insert_penalties|@>;
set_page_dimen: @<Fetch something on the |page_so_far|@>;
set_tex_shape: @<Fetch the |par_shape| size@>;
set_etex_shape: @<Fetch a penalties array element@>;
last_item: begin
  save_cur_chr:=cur_chr;
  cur_chr:=subitem;
  @<Fetch an item in the current node, if appropriate@>;
  cur_chr:=save_cur_chr;
  end;
char_given,math_given,omath_given,xmath_given:
  scanned_result(m)(int_val); {TH: TODO, doesnt work}
othercases @<Complain that |texlib| can't do this; give zero result@>
endcases;@/
exit:end;

@ @<Fetch a character code from some table@>=
begin scan_char_num;
if m=math_code_base then begin
  cur_val1:=get_math_code_num(cur_val);
  scanned_result(cur_val1)(int_val);
  end
else if m=lc_code_base then begin
  cur_val1:=get_lc_code(cur_val);
  scanned_result(cur_val1)(int_val);
  end
else if m=uc_code_base then begin
  cur_val1:=get_uc_code(cur_val);
  scanned_result(cur_val1)(int_val);
  end
else if m=sf_code_base then begin
  cur_val1:=get_sf_code(cur_val);
  scanned_result(cur_val1)(int_val);
  end
else if m=cat_code_base then begin
  cur_val1:=get_cat_code(cat_code_table,cur_val);
  scanned_result(cur_val1)(int_val);
  end
else if m<math_code_base then scanned_result(equiv(m+cur_val))(int_val)
else scanned_result(eqtb[m+cur_val].int)(int_val);
end

@ @<Fetch an ext character code from some table@>=
begin scan_char_num;
if m=math_code_base then begin
   cur_val1:=get_math_code_num(cur_val);
   scanned_result(cur_val1)(int_val);
   end
{ TH: next two lines should not be possible }
else if m<math_code_base then scanned_result(equiv(m+cur_val))(int_val)
else scanned_result(eqtb[m+cur_val].int)(int_val);
end

@ @<Fetch a token list...@>=
if level<>tok_val then
  begin print_err("Missing number, treated as zero");
@.Missing number...@>
  help3("A number should have been here; I inserted `0'.")@/
    ("(If you can't figure out why I needed to see a number,")@/
    ("look up `weird error' in the index to The TeXbook.)");
@:TeXbook}{\sl The \TeX book@>
  back_error; scanned_result(0)(dimen_val);
  end
else if cur_cmd<=assign_toks then
  begin if cur_cmd<assign_toks then {|cur_cmd=toks_register|}
    begin scan_register_num; m:=toks_base+cur_val;
    end;
  scanned_result(equiv(m))(tok_val);
  end
else  begin back_input; scan_font_ident;
  scanned_result(font_id_base+cur_val)(ident_val);
  end

@ @<Fetch a math font identifier@>=
begin scan_char_num; cur_val1:=fam_fnt(cur_val,m);
  scanned_result(cur_val1)(int_val);
  end

@ @<Fetch a math param@>=
begin cur_val1:=cur_chr; get_token;
  if cur_cmd<>math_style then
    begin print_err("Missing math style, treated as \\displaystyle");
@.Missing number...@>
    help1("A style should have been here; I inserted `\\displaystyle'.");
    cur_val:=display_style;
    back_error;
    end
  else
    cur_val:=cur_chr;
  if cur_val1<math_param_first_mu_glue then begin
    if cur_val1=math_param_radical_degree_raise then begin
      cur_val1 := get_math_param(cur_val1,cur_chr);
      scanned_result(cur_val1)(int_val);
      end
    else begin
      cur_val1 := get_math_param(cur_val1,cur_chr);
      scanned_result(cur_val1)(dimen_val);
      end;
    end
  else begin
    cur_val1 := get_math_param(cur_val1,cur_chr);
    if cur_val1=thin_mu_skip_code then cur_val1:=thin_mu_skip
    else if cur_val1=med_mu_skip_code then cur_val1:=med_mu_skip
    else if cur_val1=thick_mu_skip_code then cur_val1:=thick_mu_skip;
    scanned_result(cur_val1)(mu_val);
    end;
  end


@ Users refer to `\.{\\the\\spacefactor}' only in horizontal
mode, and to `\.{\\the\\prevdepth}' only in vertical mode; so we put the
associated mode in the modifier part of the |set_aux| command.
The |set_page_int| command has modifier 0 or 1, for `\.{\\deadcycles}' and
`\.{\\insertpenalties}', respectively. The |set_box_dimen| command is
modified by either |width_offset|, |height_offset|, or |depth_offset|.
And the |last_item| command is modified by either |int_val|, |dimen_val|,
|glue_val|, |input_line_no_code|, or |badness_code|.
\pdfTeX\ adds the codes for its extensions: |pdftex_version_code|, \dots\ .
\eTeX\ inserts |last_node_type_code| after |glue_val| and adds
the codes for its extensions: |eTeX_version_code|, \dots\ .

@d last_node_type_code=glue_val+1 {code for \.{\\lastnodetype}}
@d input_line_no_code=glue_val+2 {code for \.{\\inputlineno}}
@d badness_code=input_line_no_code+1 {code for \.{\\badness}}
@#
@d pdftex_first_rint_code     = badness_code + 1 {base for \pdfTeX's command codes}
@d pdftex_version_code        = pdftex_first_rint_code + 0 {code for \.{\\pdftexversion}}
@d pdf_last_obj_code          = pdftex_first_rint_code + 1 {code for \.{\\pdflastobj}}
@d pdf_last_xform_code        = pdftex_first_rint_code + 2 {code for \.{\\pdflastxform}}
@d pdf_last_ximage_code       = pdftex_first_rint_code + 3 {code for \.{\\pdflastximage}}
@d pdf_last_ximage_pages_code = pdftex_first_rint_code + 4 {code for \.{\\pdflastximagepages}}
@d pdf_last_annot_code        = pdftex_first_rint_code + 5 {code for \.{\\pdflastannot}}
@d pdf_last_x_pos_code        = pdftex_first_rint_code + 6 {code for \.{\\pdflastxpos}}
@d pdf_last_y_pos_code        = pdftex_first_rint_code + 7 {code for \.{\\pdflastypos}}
@d pdf_retval_code            = pdftex_first_rint_code + 8 {global multi-purpose return value}
@d pdf_last_ximage_colordepth_code = pdftex_first_rint_code + 9 {code for \.{\\pdflastximagecolordepth}}
@d random_seed_code           = pdftex_first_rint_code + 10 {code for \.{\\pdfrandomseed}}
@d pdf_last_link_code         = pdftex_first_rint_code + 11 {code for \.{\\pdflastlink}}
@d luatex_version_code        = pdftex_first_rint_code + 12 {code for \.{\\luatexversion}}
@d pdftex_last_item_codes     = pdftex_first_rint_code + 12 {end of \pdfTeX's command codes}
@#
@d Aleph_int=pdftex_last_item_codes+1 {first of \Aleph\ codes for integers}
@d Aleph_int_num=5 {number of \Aleph\ integers}
@d eTeX_int=Aleph_int+Aleph_int_num {first of \eTeX\ codes for integers}
@d eTeX_dim=eTeX_int+8 {first of \eTeX\ codes for dimensions}
@d eTeX_glue=eTeX_dim+9 {first of \eTeX\ codes for glue}
@d eTeX_mu=eTeX_glue+1 {first of \eTeX\ codes for muglue}
@d eTeX_expr=eTeX_mu+1 {first of \eTeX\ codes for expressions}

@<Put each...@>=
primitive_tex("spacefactor",set_aux,hmode,0);
@!@:space_factor_}{\.{\\spacefactor} primitive@>
primitive_tex("prevdepth",set_aux,vmode,0);@/
@!@:prev_depth_}{\.{\\prevdepth} primitive@>
primitive_tex("deadcycles",set_page_int,0,0);
@!@:dead_cycles_}{\.{\\deadcycles} primitive@>
primitive_tex("insertpenalties",set_page_int,1,0);
@!@:insert_penalties_}{\.{\\insertpenalties} primitive@>
primitive_tex("wd",set_box_dimen,width_offset,0);
@!@:wd_}{\.{\\wd} primitive@>
primitive_tex("ht",set_box_dimen,height_offset,0);
@!@:ht_}{\.{\\ht} primitive@>
primitive_tex("dp",set_box_dimen,depth_offset,0);
@!@:dp_}{\.{\\dp} primitive@>
primitive_tex("lastpenalty",last_item,int_val,0);
@!@:last_penalty_}{\.{\\lastpenalty} primitive@>
primitive_tex("lastkern",last_item,dimen_val,0);
@!@:last_kern_}{\.{\\lastkern} primitive@>
primitive_tex("lastskip",last_item,glue_val,0);
@!@:last_skip_}{\.{\\lastskip} primitive@>
primitive_tex("inputlineno",last_item,input_line_no_code,0);
@!@:input_line_no_}{\.{\\inputlineno} primitive@>
primitive_tex("badness",last_item,badness_code,0);
@!@:badness_}{\.{\\badness} primitive@>
primitive_pdftex("pdftexversion",last_item,pdftex_version_code,0);@/
@!@:pdftex_version_}{\.{\\pdftexversion} primitive@>
primitive_luatex("luatexversion",last_item,luatex_version_code,0);@/
@!@:luatex_version_}{\.{\\luatexversion} primitive@>
primitive_pdftex("pdflastobj",last_item,pdf_last_obj_code,0);@/
@!@:pdf_last_obj_}{\.{\\pdflastobj} primitive@>
primitive_pdftex("pdflastxform",last_item,pdf_last_xform_code,0);@/
@!@:pdf_last_xform_}{\.{\\pdflastxform} primitive@>
primitive_pdftex("pdflastximage",last_item,pdf_last_ximage_code,0);@/
@!@:pdf_last_ximage_}{\.{\\pdflastximage} primitive@>
primitive_pdftex("pdflastximagepages",last_item,pdf_last_ximage_pages_code,0);@/
@!@:pdf_last_ximage_pages_}{\.{\\pdflastximagepages} primitive@>
primitive_pdftex("pdflastannot",last_item,pdf_last_annot_code,0);@/
@!@:pdf_last_annot_}{\.{\\pdflastannot} primitive@>
primitive_pdftex("pdflastxpos",last_item,pdf_last_x_pos_code,0);@/
@!@:pdf_last_x_pos_}{\.{\\pdflastxpos} primitive@>
primitive_pdftex("pdflastypos",last_item,pdf_last_y_pos_code,0);@/
@!@:pdf_last_y_pos_}{\.{\\pdflastypos} primitive@>
primitive_pdftex("pdfretval",last_item,pdf_retval_code,0);@/
@!@:pdf_retval_}{\.{\\pdfretval} primitive@>
primitive_pdftex("pdflastximagecolordepth",last_item,pdf_last_ximage_colordepth_code,0);@/
@!@:pdf_last_ximage_colordepth_}{\.{\\pdflastximagecolordepth} primitive@>
primitive_pdftex("pdfrandomseed",last_item,random_seed_code,0);
@!@:random_seed_}{\.{\\pdfrandomseed} primitive@>
primitive_pdftex("pdflastlink",last_item,pdf_last_link_code,0);@/
@!@:pdf_last_link_}{\.{\\pdflastlink} primitive@>

@ @<Fetch the |space_factor| or the |prev_depth|@>=
if abs(mode)<>m then
  begin print_err("Improper "); print_cmd_chr(set_aux,m);
@.Improper \\spacefactor@>
@.Improper \\prevdepth@>
  help4("You can refer to \spacefactor only in horizontal mode;")@/
    ("you can refer to \prevdepth only in vertical mode; and")@/
    ("neither of these is meaningful inside \write. So")@/
    ("I'm forgetting what you said and using zero instead.");
  error;
  if level<>tok_val then scanned_result(0)(dimen_val)
  else scanned_result(0)(int_val);
  end
else if m=vmode then scanned_result(prev_depth)(dimen_val)
else scanned_result(space_factor)(int_val)

@ @<Fetch the |dead_cycles| or the |insert_penalties|@>=
begin if m=0 then cur_val:=dead_cycles
@/@<Cases for `Fetch the |dead_cycles| or the |insert_penalties|'@>@/
else cur_val:=insert_penalties;
cur_val_level:=int_val;
end

@ @<Fetch a box dimension@>=
begin scan_register_num;
if box(cur_val)=null then cur_val:=0 @+else cur_val:=vmem(box(cur_val)+m).sc;
cur_val_level:=dimen_val;
end

@ Inside an \.{\\output} routine, a user may wish to look at the page totals
that were present at the moment when output was triggered.

@d max_dimen==@'7777777777 {$2^{30}-1$}

@<Fetch something on the |page_so_far|@>=
begin if (page_contents=empty) and (not output_active) then
  if m=0 then cur_val:=max_dimen@+else cur_val:=0
else cur_val:=page_so_far[m];
cur_val_level:=dimen_val;
end

@ @<Fetch the |prev_graf|@>=
if mode=0 then scanned_result(0)(int_val) {|prev_graf=0| within \.{\\write}}
else begin nest[nest_ptr]:=cur_list; p:=nest_ptr;
  while abs(nest[p].mode_field)<>vmode do decr(p);
  scanned_result(nest[p].pg_field)(int_val);
  end

@ @<Fetch the |par_shape| size@>=
begin if par_shape_ptr=null then cur_val:=0
else cur_val:=vinfo(par_shape_ptr+1);
cur_val_level:=int_val;
end

@ Here is where \.{\\lastpenalty}, \.{\\lastkern}, and \.{\\lastskip} are
implemented. The reference count for \.{\\lastskip} will be updated later.

We also handle \.{\\inputlineno} and \.{\\badness} here, because they are
legal in similar contexts.

@<Fetch an item in the current node...@>=
if m>=input_line_no_code then
 if m>=eTeX_glue then @<Process an expression and |return|@>@;
 else if m>=eTeX_dim then
  begin case m of
  @/@<Cases for fetching a dimension value@>@/
  end; {there are no other cases}
  cur_val_level:=dimen_val;
  end
 else begin case m of
  input_line_no_code: cur_val:=line;
  badness_code: cur_val:=last_badness;
  pdftex_version_code:  cur_val := pdftex_version;
  luatex_version_code:  cur_val := luatex_version;
  pdf_last_obj_code:    cur_val := pdf_last_obj;
  pdf_last_xform_code:  cur_val := pdf_last_xform;
  pdf_last_ximage_code: cur_val := pdf_last_ximage;
  pdf_last_ximage_pages_code: cur_val := pdf_last_ximage_pages;
  pdf_last_annot_code:  cur_val := pdf_last_annot;
  pdf_last_x_pos_code:  cur_val := pdf_last_x_pos;
  pdf_last_y_pos_code:  cur_val := pdf_last_y_pos;
  pdf_retval_code:      cur_val := pdf_retval;
  pdf_last_ximage_colordepth_code: cur_val := pdf_last_ximage_colordepth;
  random_seed_code:  cur_val := random_seed;
  pdf_last_link_code:   cur_val := pdf_last_link;
  @/@<Cases for fetching an integer value@>@/
  end; {there are no other cases}
  cur_val_level:=int_val;
  end
else begin if cur_chr=glue_val then cur_val:=zero_glue@+else cur_val:=0;
  if cur_chr=last_node_type_code then
    begin cur_val_level:=int_val;
    if (tail=head)or(mode=0) then cur_val:=-1;
    end
  else cur_val_level:=cur_chr;
  {TODO: check this thoroughly! The structural change to the
   |is_char_node| macro was wreaking havoc here, and possibly elsewhere.}
  if tail<>contrib_head and not is_char_node(tail)and(mode<>0) then
    case cur_chr of
    int_val: if type(tail)=penalty_node then cur_val:=penalty(tail);
    dimen_val: if type(tail)=kern_node then cur_val:=width(tail);
    glue_val: if type(tail)=glue_node then
      begin cur_val:=glue_ptr(tail);
      if subtype(tail)=mu_glue then cur_val_level:=mu_val;
      end;
    last_node_type_code:
      cur_val := visible_last_node_type(tail);
    end {there are no other cases}
  else if (mode=vmode)and(tail=head) then
    case cur_chr of
    int_val: cur_val:=last_penalty;
    dimen_val: cur_val:=last_kern;
    glue_val: if last_glue<>max_halfword then cur_val:=last_glue;
    last_node_type_code: cur_val:=last_node_type;
    end; {there are no other cases}
  end

@ @<Fetch a font dimension@>=
get_font_dimen

@ @<Fetch a font integer@>=
begin scan_font_ident;
if m=0 then scanned_result(hyphen_char(cur_val))(int_val)
else if m=1 then scanned_result(skew_char(cur_val))(int_val)
else if m=no_lig_code then scanned_result(test_no_ligatures(cur_val))(int_val)
else begin
    n := cur_val;
    scan_char_num;
    k := cur_val;
    case m of
    lp_code_base: scanned_result(get_lp_code(n, k))(int_val);
    rp_code_base: scanned_result(get_rp_code(n, k))(int_val);
    ef_code_base: scanned_result(get_ef_code(n, k))(int_val);
    tag_code: scanned_result(get_tag_code(n, k))(int_val);
    end;
end;
end

@ @<Fetch a register@>=
begin scan_register_num;
case m of
int_val:cur_val:=count(cur_val);
attr_val:cur_val:=attribute(cur_val);
dimen_val:cur_val:=dimen(cur_val);
glue_val: cur_val:=skip(cur_val);
mu_val: cur_val:=mu_skip(cur_val);
end; {there are no other cases}
cur_val_level:=m;
end

@ @<Complain that \.{\\the} can't do this; give zero result@>=
begin print_err("You can't use `"); print_cmd_chr(cur_cmd,cur_chr);
@.You can't use x after ...@>
print("' after "); print_esc("the");
help1("I'm forgetting what you said and using zero instead.");
error;
if level<>tok_val then scanned_result(0)(dimen_val)
else scanned_result(0)(int_val);
end

@ @<Complain that |texlib| can't do this; give zero result@>=
begin print_err("You can't use `"); print_cmd_chr(cmd,m);
print("' as tex library index");
help1("I'm forgetting what you said and using zero instead.");
error;
if level<>tok_val then scanned_result(0)(dimen_val)
else scanned_result(0)(int_val);
end


@ When a |glue_val| changes to a |dimen_val|, we use the width component
of the glue; there is no need to decrease the reference count, since it
has not yet been increased.  When a |dimen_val| changes to an |int_val|,
we use scaled points so that the value doesn't actually change. And when a
|mu_val| changes to a |glue_val|, the value doesn't change either.

@<Convert \(c)|cur_val| to a lower level@>=
begin if cur_val_level=glue_val then cur_val:=width(cur_val)
else if cur_val_level=mu_val then mu_error;
decr(cur_val_level);
end

@ If |cur_val| points to a glue specification at this point, the reference
count for the glue does not yet include the reference by |cur_val|.
If |negative| is |true|, |cur_val_level| is known to be |<=mu_val|.

@<Fix the reference count, if any, ...@>=
if negative then begin
  if cur_val_level>=glue_val then
    begin cur_val:=new_spec(cur_val);
    @<Negate all three glue components of |cur_val|@>;
    end
  else negate(cur_val);
  end
else if (cur_val_level>=glue_val)and(cur_val_level<=mu_val) then
  add_glue_ref(cur_val)

@ @<Negate all three...@>=
begin negate(width(cur_val));
negate(stretch(cur_val));
negate(shrink(cur_val));
end

@ Our next goal is to write the |scan_int| procedure, which scans anything that
\TeX\ treats as an integer. But first we might as well look at some simple
applications of |scan_int| that have already been made inside of
|scan_something_internal|.

@
@d dir_T=0
@d dir_L=1
@d dir_B=2
@d dir_R=3
@d dir_eq_end(#)==(#)
@d dir_eq(#)==(#)=dir_eq_end
@d dir_ne_end(#)==(#)
@d dir_ne(#)==(#)<>dir_ne_end
@d dir_opposite_end(#)==((#) mod 4)
@d dir_opposite(#)==(((#)+2) mod 4)=dir_opposite_end
@d dir_parallel_end(#)==((#) mod 2)
@d dir_parallel(#)==((#) mod 2)=dir_parallel_end
@d dir_orthogonal_end(#)==(# mod 2)
@d dir_orthogonal(#)==((#) mod 2)<>dir_orthogonal_end
@d dir_next_end(#)==((#) mod 4)
@d dir_next(#)==(((#)+3) mod 4)=dir_next_end
@d dir_prev_end(#)==((#) mod 4)
@d dir_prev(#)==(((#)+1) mod 4)=dir_prev_end

@d dir_horizontal(#)==(((#)=dir_L) or ((#)=dir_R))
@d dir_vertical(#)==(((#)=dir_T) or ((#)=dir_B))

{box directions}
@d dir_TL_=0
@d dir_TR_=1
@d dir_LT_=2
@d dir_LB_=3
@d dir_BL_=4
@d dir_BR_=5
@d dir_RT_=6
@d dir_RB_=7

{font directions}
@d dir__LT= 0
@d dir__LL= 1
@d dir__LB= 2
@d dir__LR= 3
@d dir__RT= 4
@d dir__RL= 5
@d dir__RB= 6
@d dir__RR= 7
@d dir__TT= 8
@d dir__TL= 9
@d dir__TB=10
@d dir__TR=11
@d dir__BT=12
@d dir__BL=13
@d dir__BB=14
@d dir__BR=15

@d is_mirrored(#)==(dir_opposite(dir_primary[#])(dir_tertiary[#]))
@d is_rotated(#)==(dir_parallel(dir_secondary[#])(dir_tertiary[#]))
@d font_direction(#)==(# mod 16)
@d box_direction(#)==(# div 4)

@ It is nice to have routines that say what they do, so the original
|scan_eight_bit_int| is superceded by |scan_register_num| and
|scan_mark_num|. It may become split up even further in the future.

@<Declare procedures that scan restricted classes of integers@>=
procedure scan_register_num;
begin scan_int;
if (cur_val<0)or(cur_val>biggest_reg) then
  begin print_err("Bad register code");
@.Bad register code@>
  help2("A register number must be between 0 and 65535.")@/
    ("I changed this one to zero."); int_error(cur_val); cur_val:=0;
  end;
end;
procedure scan_mark_num;
begin scan_int;
if (cur_val<0)or(cur_val>biggest_mark) then
  begin print_err("Bad marks code");
@.Bad marks code@>
  help2("A marks class must be between 0 and 65535.")@/
    ("I changed this one to zero."); int_error(cur_val); cur_val:=0;
  end;
end;

@ @<Declare procedures that scan restricted classes of integers@>=
procedure scan_char_num;
begin scan_int;
if (cur_val<0)or(cur_val>biggest_char) then
  begin print_err("Bad character code");
@.Bad character code@>
  help2("A character number must be between 0 and biggest_char.")@/
    ("I changed this one to zero."); int_error(cur_val); cur_val:=0;
  end;
end;

@ While we're at it, we might as well deal with similar routines that
will be needed later.

@<Declare procedures that scan restricted classes of integers@>=
procedure scan_four_bit_int;
begin scan_int;
if (cur_val<0)or(cur_val>15) then
  begin print_err("Bad number");
@.Bad number@>
  help2("Since I expected to read a number between 0 and 15,")@/
    ("I changed this one to zero."); int_error(cur_val); cur_val:=0;
  end;
end;
procedure scan_math_family_int;
begin scan_int;
if (cur_val<0)or(cur_val>255) then
  begin print_err("Bad number");
@.Bad number@>
  help2("Since I expected to read a number between 0 and 255,")@/
    ("I changed this one to zero."); int_error(cur_val); cur_val:=0;
  end;
end;

@ @<Declare procedures that scan restricted classes of integers@>=
procedure scan_real_fifteen_bit_int;
begin scan_int;
if (cur_val<0)or(cur_val>@'77777) then
  begin print_err("Bad mathchar");
@.Bad mathchar@>
  help2("A mathchar number must be between 0 and 32767.")@/
    ("I changed this one to zero."); int_error(cur_val); cur_val:=0;
  end;
end;
procedure scan_fifteen_bit_int;
begin scan_int;
if (cur_val<0)or(cur_val>@'77777) then
  begin print_err("Bad mathchar");
@.Bad mathchar@>
  help2("A mathchar number must be between 0 and 32767.")@/
    ("I changed this one to zero."); int_error(cur_val); cur_val:=0;
  end;
cur_val := ((cur_val div @"1000) * @"1000000) +
           (((cur_val mod @"1000) div @"100) * @"10000) +
           (cur_val mod @"100);
end;
procedure scan_big_fifteen_bit_int;
begin scan_int;
if (cur_val<0)or(cur_val>@"7FFFFFF) then
  begin print_err("Bad extended mathchar");
@.Bad mathchar@>
  help2("An extended mathchar number must be between 0 and ""7FFFFFF.")@/
    ("I changed this one to zero."); int_error(cur_val); cur_val:=0;
  end;
end;


@ @<Declare procedures that scan restricted classes of integers@>=
procedure scan_twenty_seven_bit_int;
begin scan_int;
if (cur_val<0)or(cur_val>@'777777777) then
  begin print_err("Bad delimiter code");
@.Bad delimiter code@>
  help2("A numeric delimiter code must be between 0 and 2^{27}-1.")@/
    ("I changed this one to zero."); int_error(cur_val); cur_val:=0;
  end;
end;

procedure scan_fifty_one_bit_int;
var iiii:integer;
begin scan_int;
if (cur_val<0)or(cur_val>@'777777777) then
  begin print_err("Bad delimiter code");
@.Bad delimiter code@>
  help2("A numeric delimiter (first part) must be between 0 and 2^{27}-1.")
    ("I changed this one to zero."); int_error(cur_val); cur_val:=0;
  end;
iiii:=cur_val;
scan_int;
if (cur_val<0)or(cur_val>@"FFFFFF) then
  begin print_err("Bad delimiter code");
@.Bad delimiter code@>
help2("A numeric delimiter (second part) must be between 0 and 2^{24}-1.")@/
    ("I changed this one to zero."); int_error(cur_val); cur_val:=0;
  end;
cur_val1:=cur_val;
cur_val:=iiii;
end;


procedure scan_string_argument;
var s:integer;
begin
scan_left_brace;
get_x_token;
while (cur_cmd<>right_brace) do
  begin
  if (cur_cmd=letter) or (cur_cmd=other_char) then begin
    str_room(1); append_char(cur_chr);
    end
  else if (cur_cmd=spacer) then begin
    str_room(1); append_char(" ");
    end
  else begin
    print("Bad token appearing in string argument");
    end;
  get_x_token;
  end;
s:=make_string;
if str_eq_str("mi",s) then s:="mi";
if str_eq_str("mo",s) then s:="mo";
if str_eq_str("mn",s) then s:="mn";
cur_val:=s;
end;

@ An integer number can be preceded by any number of spaces and `\.+' or
`\.-' signs. Then comes either a decimal constant (i.e., radix 10), an
octal constant (i.e., radix 8, preceded by~\.\'), a hexadecimal constant
(radix 16, preceded by~\."), an alphabetic constant (preceded by~\.\`), or
an internal variable. After scanning is complete,
|cur_val| will contain the answer, which must be at most
$2^{31}-1=2147483647$ in absolute value. The value of |radix| is set to
10, 8, or 16 in the cases of decimal, octal, or hexadecimal constants,
otherwise |radix| is set to zero. An optional space follows a constant.

@d octal_token=other_token+"'" {apostrophe, indicates an octal constant}
@d hex_token=other_token+"""" {double quote, indicates a hex constant}
@d alpha_token=other_token+"`" {reverse apostrophe, precedes alpha constants}
@d point_token=other_token+"." {decimal point}
@d continental_point_token=other_token+"," {decimal point, Eurostyle}

@<Glob...@>=
@!radix:small_number; {|scan_int| sets this to 8, 10, 16, or zero}

@ We initialize the following global variables just in case |expand|
comes into action before any of the basic scanning routines has assigned
them a value.

@<Set init...@>=
cur_val:=0; cur_val_level:=int_val; radix:=0; cur_order:=normal;

@ The |scan_int| routine is used also to scan the integer part of a
fraction; for example, the `\.3' in `\.{3.14159}' will be found by
|scan_int|. The |scan_dimen| routine assumes that |cur_tok=point_token|
after the integer part of such a fraction has been scanned by |scan_int|,
and that the decimal point has been backed up to be scanned again.

@p procedure scan_int; {sets |cur_val| to an integer}
label done, restart;
var negative:boolean; {should the answer be negated?}
@!m:integer; {|@t$2^{31}$@> div radix|, the threshold of danger}
@!d:small_number; {the digit just scanned}
@!vacuous:boolean; {have no digits appeared?}
@!OK_so_far:boolean; {has an error message been issued?}
begin radix:=0; OK_so_far:=true;@/
@<Get the next non-blank non-sign token; set |negative| appropriately@>;
restart:
if cur_tok=alpha_token then @<Scan an alphabetic character code into |cur_val|@>
else if cur_tok=cs_token_flag+frozen_primitive then
  @<Reset |cur_tok| for unexpandable primitives, goto restart@>
else if cur_cmd=math_style then
  cur_val:=cur_chr
else if (cur_cmd>=min_internal)and(cur_cmd<=max_internal) then
  scan_something_internal(int_val,false)
else @<Scan a numeric constant@>;
if negative then negate(cur_val);
end;

@ @<Get the next non-blank non-sign token...@>=
negative:=false;
repeat @<Get the next non-blank non-call token@>;
if cur_tok=other_token+"-" then
  begin negative := not negative; cur_tok:=other_token+"+";
  end;
until cur_tok<>other_token+"+"

@ A space is ignored after an alphabetic character constant, so that
such constants behave like numeric ones.

@<Scan an alphabetic character code into |cur_val|@>=
begin get_token; {suppress macro expansion}
if cur_tok<cs_token_flag then
  begin cur_val:=cur_chr;
  if cur_cmd<=right_brace then begin
    if cur_cmd=right_brace then incr(align_state)
    else decr(align_state);
    end;
  end
else begin {the value of a csname in this context is its name}
  if is_active_csname(cur_tok-cs_token_flag) then
    cur_val:=active_csname_value(cur_tok-cs_token_flag)
  else if single_letter(text(cur_tok-cs_token_flag)) then
    cur_val:=pool_to_unichar(str_start_macro(text(cur_tok-cs_token_flag)))
  else
    cur_val:=too_big_char;
end;
if cur_val>biggest_char then
  begin print_err("Improper alphabetic constant");
@.Improper alphabetic constant@>
  help2("A one-character control sequence belongs after a ` mark.")@/
    ("So I'm essentially inserting \0 here.");
  cur_val:="0"; back_error;
  end
else @<Scan an optional space@>;
end

@ @<Scan an optional space@>=
begin get_x_token; if cur_cmd<>spacer then back_input;
end

@ @<Scan a numeric constant@>=
begin radix:=10; m:=214748364;
if cur_tok=octal_token then
  begin radix:=8; m:=@'2000000000; get_x_token;
  end
else if cur_tok=hex_token then
  begin radix:=16; m:=@'1000000000; get_x_token;
  end;
vacuous:=true; cur_val:=0;@/
@<Accumulate the constant until |cur_tok| is not a suitable digit@>;
if vacuous then @<Express astonishment that no number was here@>
else if cur_cmd<>spacer then back_input;
end

@ @d infinity==@'17777777777 {the largest positive value that \TeX\ knows}
@d zero_token=other_token+"0" {zero, the smallest digit}
@d A_token=letter_token+"A" {the smallest special hex digit}
@d other_A_token=other_token+"A" {special hex digit of type |other_char|}

@<Accumulate the constant...@>=
loop@+  begin if (cur_tok<zero_token+radix)and(cur_tok>=zero_token)and
    (cur_tok<=zero_token+9) then d:=cur_tok-zero_token
  else if radix=16 then
    if (cur_tok<=A_token+5)and(cur_tok>=A_token) then d:=cur_tok-A_token+10
    else if (cur_tok<=other_A_token+5)and(cur_tok>=other_A_token) then
      d:=cur_tok-other_A_token+10
    else goto done
  else goto done;
  vacuous:=false;
  if (cur_val>=m)and((cur_val>m)or(d>7)or(radix<>10)) then
    begin if OK_so_far then
      begin print_err("Number too big");
@.Number too big@>
      help2("I can only go up to 2147483647='17777777777=""7FFFFFFF,")@/
        ("so I'm using that number instead of yours.");
      error; cur_val:=infinity; OK_so_far:=false;
      end;
    end
  else cur_val:=cur_val*radix+d;
  get_x_token;
  end;
done:

@ @<Express astonishment...@>=
begin print_err("Missing number, treated as zero");
@.Missing number...@>
help3("A number should have been here; I inserted `0'.")@/
  ("(If you can't figure out why I needed to see a number,")@/
  ("look up `weird error' in the index to The TeXbook.)");
@:TeXbook}{\sl The \TeX book@>
back_error;
end

@ The |scan_dimen| routine is similar to |scan_int|, but it sets |cur_val| to
a |scaled| value, i.e., an integral number of sp. One of its main tasks
is therefore to interpret the abbreviations for various kinds of units and
to convert measurements to scaled points.

There are three parameters: |mu| is |true| if the finite units must be
`\.{mu}', while |mu| is |false| if `\.{mu}' units are disallowed;
|inf| is |true| if the infinite units `\.{fil}', `\.{fill}', `\.{filll}'
are permitted; and |shortcut| is |true| if |cur_val| already contains
an integer and only the units need to be considered.

The order of infinity that was found in the case of infinite glue is returned
in the global variable |cur_order|.

@<Glob...@>=
@!cur_order:glue_ord; {order of infinity found by |scan_dimen|}

@ Constructions like `\.{-\'77 pt}' are legal dimensions, so |scan_dimen|
may begin with |scan_int|. This explains why it is convenient to use
|scan_int| also for the integer part of a decimal fraction.

Several branches of |scan_dimen| work with |cur_val| as an integer and
with an auxiliary fraction |f|, so that the actual quantity of interest is
$|cur_val|+|f|/2^{16}$. At the end of the routine, this ``unpacked''
representation is put into the single word |cur_val|, which suddenly
switches significance from |integer| to |scaled|.

@d attach_fraction=88 {go here to pack |cur_val| and |f| into |cur_val|}
@d attach_sign=89 {go here when |cur_val| is correct except perhaps for sign}
@d scan_normal_dimen==scan_dimen(false,false,false)

@p procedure scan_dimen(@!mu,@!inf,@!shortcut:boolean);
  {sets |cur_val| to a dimension}
label done, done1, done2, found, not_found, attach_fraction, attach_sign;
var negative:boolean; {should the answer be negated?}
@!f:integer; {numerator of a fraction whose denominator is $2^{16}$}
@<Local variables for dimension calculations@>@;
begin f:=0; arith_error:=false; cur_order:=normal; negative:=false;
if not shortcut then
  begin @<Get the next non-blank non-sign...@>;
  if (cur_cmd>=min_internal)and(cur_cmd<=max_internal) then
    @<Fetch an internal dimension and |goto attach_sign|,
      or fetch an internal integer@>
  else  begin back_input;
    if cur_tok=continental_point_token then cur_tok:=point_token;
    if cur_tok<>point_token then scan_int
    else  begin radix:=10; cur_val:=0;
      end;
    if cur_tok=continental_point_token then cur_tok:=point_token;
    if (radix=10)and(cur_tok=point_token) then @<Scan decimal fraction@>;
    end;
  end;
if cur_val<0 then {in this case |f=0|}
  begin negative := not negative; negate(cur_val);
  end;
@<Scan units and set |cur_val| to $x\cdot(|cur_val|+f/2^{16})$, where there
  are |x| sp per unit; |goto attach_sign| if the units are internal@>;
@<Scan an optional space@>;
attach_sign: if arith_error or(abs(cur_val)>=@'10000000000) then
  @<Report that this dimension is out of range@>;
if negative then negate(cur_val);
end;

@ @<Fetch an internal dimension and |goto attach_sign|...@>=
if mu then
  begin scan_something_internal(mu_val,false);
  @<Coerce glue to a dimension@>;
  if cur_val_level=mu_val then goto attach_sign;
  if cur_val_level<>int_val then mu_error;
  end
else  begin scan_something_internal(dimen_val,false);
  if cur_val_level=dimen_val then goto attach_sign;
  end

@ @<Local variables for dimension calculations@>=
@!num,@!denom:1..65536; {conversion ratio for the scanned units}
@!k,@!kk:small_number; {number of digits in a decimal fraction}
@!p,@!q:pointer; {top of decimal digit stack}
@!v:scaled; {an internal dimension}
@!save_cur_val:integer; {temporary storage of |cur_val|}

@ The following code is executed when |scan_something_internal| was
called asking for |mu_val|, when we really wanted a ``mudimen'' instead
of ``muglue.''

@<Coerce glue to a dimension@>=
if cur_val_level>=glue_val then
  begin v:=width(cur_val); delete_glue_ref(cur_val); cur_val:=v;
  end

@ When the following code is executed, we have |cur_tok=point_token|, but this
token has been backed up using |back_input|; we must first discard it.

It turns out that a decimal point all by itself is equivalent to `\.{0.0}'.
Let's hope people don't use that fact.

@<Scan decimal fraction@>=
begin k:=0; p:=null; get_token; {|point_token| is being re-scanned}
loop@+  begin get_x_token;
  if (cur_tok>zero_token+9)or(cur_tok<zero_token) then goto done1;
  if k<17 then {digits for |k>=17| cannot affect the result}
    begin q:=get_avail; link(q):=p; info(q):=cur_tok-zero_token;
    p:=q; incr(k);
    end;
  end;
done1: for kk:=k downto 1 do
  begin dig[kk-1]:=info(p); q:=p; p:=link(p); free_avail(q);
  end;
f:=round_decimals(k);
if cur_cmd<>spacer then back_input;
end

@ Now comes the harder part: At this point in the program, |cur_val| is a
nonnegative integer and $f/2^{16}$ is a nonnegative fraction less than 1;
we want to multiply the sum of these two quantities by the appropriate
factor, based on the specified units, in order to produce a |scaled|
result, and we want to do the calculation with fixed point arithmetic that
does not overflow.

@<Scan units and set |cur_val| to $x\cdot(|cur_val|+f/2^{16})$...@>=
if inf then @<Scan for \(f)\.{fil} units; |goto attach_fraction| if found@>;
@<Scan for \(u)units that are internal dimensions;
  |goto attach_sign| with |cur_val| set if found@>;
if mu then @<Scan for \(m)\.{mu} units and |goto attach_fraction|@>;
if scan_keyword('true') then @<Adjust \(f)for the magnification ratio@>;
@.true@>
if scan_keyword('pt') then goto attach_fraction; {the easy case}
@.pt@>
@<Scan for \(a)all other units and adjust |cur_val| and |f| accordingly;
  |goto done| in the case of scaled points@>;
attach_fraction: if cur_val>=@'40000 then arith_error:=true
else cur_val:=cur_val*unity+f;
done:

@ In traditional TeX, a specification like `\.{filllll}' or `\.{fill L L
L}' will lead to two error messages (one for each additional keyword
\.{"l"}).

Not so for luatex, it just parses the construct in reverse.

@<Scan for \(f)\.{fil} units...@>=
begin
if scan_keyword('filll') then begin cur_order:=filll; goto attach_fraction; end
else if scan_keyword('fill') then begin cur_order:=fill; goto attach_fraction; end
else if scan_keyword('fil') then begin cur_order:=fil; goto attach_fraction; end
else if scan_keyword('fi') then begin cur_order:=sfi; goto attach_fraction; end;
end

@ @<Scan for \(u)units that are internal dimensions...@>=
save_cur_val:=cur_val;
@<Get the next non-blank non-call...@>;
if (cur_cmd<min_internal)or(cur_cmd>max_internal) then back_input
else  begin if mu then
    begin scan_something_internal(mu_val,false); @<Coerce glue...@>;
    if cur_val_level<>mu_val then mu_error;
    end
  else scan_something_internal(dimen_val,false);
  v:=cur_val; goto found;
  end;
if mu then goto not_found;
if scan_keyword('em') then v:=(@<The em width for |cur_font|@>)
@.em@>
else if scan_keyword('ex') then v:=(@<The x-height for |cur_font|@>)
@.ex@>
else if scan_keyword('px') then v:=pdf_px_dimen
@.px@>
else goto not_found;
@<Scan an optional space@>;
found:cur_val:=nx_plus_y(save_cur_val,v,xn_over_d(v,f,@'200000));
goto attach_sign;
not_found:

@ @<Scan for \(m)\.{mu} units and |goto attach_fraction|@>=
begin
if scan_keyword('mu') then goto attach_fraction
@.mu@>
else  begin print_err("Illegal unit of measure ("); print("mu inserted)");
@.Illegal unit of measure@>
  help4("The unit of measurement in math glue must be mu.")@/
    ("To recover gracefully from this error, it's best to")@/
    ("delete the erroneous units; e.g., type `2' to delete")@/
    ("two letters. (See Chapter 27 of The TeXbook.)");
@:TeXbook}{\sl The \TeX book@>
  error; goto attach_fraction;
  end;
end

@ @<Adjust \(f)for the magnification ratio@>=
begin prepare_mag;
if mag<>1000 then
  begin cur_val:=xn_over_d(cur_val,1000,mag);
  f:=(1000*f+@'200000*remainder) div mag;
  cur_val:=cur_val+(f div @'200000); f:=f mod @'200000;
  end;
end

@ The necessary conversion factors can all be specified exactly as
fractions whose numerator and denominator add to 32768 or less.
According to the definitions here, $\rm2660\,dd\approx1000.33297\,mm$;
this agrees well with the value $\rm1000.333\,mm$ cited by Bosshard
@^Bosshard, Hans Rudolf@>
in {\sl Technische Grundlagen zur Satzherstellung\/} (Bern, 1980).
The Didot point has been newly standardized in 1978;
it's now exactly $\rm 1\,nd=0.375\,mm$.
Conversion uses the equation $0.375=21681/20320/72.27\cdot25.4$.
The new Cicero follows the new Didot point; $\rm 1\,nc=12\,nd$.
These would lead to the ratios $21681/20320$ and $65043/5080$,
respectively.
The closest approximations supported by the algorithm would be
$11183/10481$ and $1370/107$.  In order to maintain the
relation $\rm 1\,nc=12\,nd$, we pick the ratio $685/642$ for
$\rm nd$, however.

@d set_conversion_end(#)== denom:=#; end
@d set_conversion(#)==@+begin num:=#; set_conversion_end

@<Scan for \(a)all other units and adjust |cur_val| and |f|...@>=
if scan_keyword('in') then set_conversion(7227)(100)
@.in@>
else if scan_keyword('pc') then set_conversion(12)(1)
@.pc@>
else if scan_keyword('cm') then set_conversion(7227)(254)
@.cm@>
else if scan_keyword('mm') then set_conversion(7227)(2540)
@.mm@>
else if scan_keyword('bp') then set_conversion(7227)(7200)
@.bp@>
else if scan_keyword('dd') then set_conversion(1238)(1157)
@.dd@>
else if scan_keyword('cc') then set_conversion(14856)(1157)
@.cc@>
else if scan_keyword('nd') then set_conversion(685)(642)
@.nd@>
else if scan_keyword('nc') then set_conversion(1370)(107)
@.nc@>
else if scan_keyword('sp') then goto done
@.sp@>
else @<Complain about unknown unit and |goto done2|@>;
cur_val:=xn_over_d(cur_val,num,denom);
f:=(num*f+@'200000*remainder) div denom;@/
cur_val:=cur_val+(f div @'200000); f:=f mod @'200000;
done2:

@ @<Complain about unknown unit...@>=
begin print_err("Illegal unit of measure ("); print("pt inserted)");
@.Illegal unit of measure@>
help6("Dimensions can be in units of em, ex, in, pt, pc,")@/
  ("cm, mm, dd, cc, nd, nc, bp, or sp; but yours is a new one!")@/
  ("I'll assume that you meant to say pt, for printer's points.")@/
  ("To recover gracefully from this error, it's best to")@/
  ("delete the erroneous units; e.g., type `2' to delete")@/
  ("two letters. (See Chapter 27 of The TeXbook.)");
@:TeXbook}{\sl The \TeX book@>
error; goto done2;
end


@ @<Report that this dimension is out of range@>=
begin print_err("Dimension too large");
@.Dimension too large@>
help2("I can't work with sizes bigger than about 19 feet.")@/
  ("Continue and I'll use the largest value I can.");@/
error; cur_val:=max_dimen; arith_error:=false;
end

@ The final member of \TeX's value-scanning trio is |scan_glue|, which
makes |cur_val| point to a glue specification. The reference count of that
glue spec will take account of the fact that |cur_val| is pointing to~it.

The |level| parameter should be either |glue_val| or |mu_val|.

Since |scan_dimen| was so much more complex than |scan_int|, we might expect
|scan_glue| to be even worse. But fortunately, it is very simple, since
most of the work has already been done.

@p procedure scan_glue(@!level:small_number);
  {sets |cur_val| to a glue spec pointer}
label exit;
var negative:boolean; {should the answer be negated?}
@!q:pointer; {new glue specification}
@!mu:boolean; {does |level=mu_val|?}
begin mu:=(level=mu_val); @<Get the next non-blank non-sign...@>;
if (cur_cmd>=min_internal)and(cur_cmd<=max_internal) then
  begin scan_something_internal(level,negative);
  if cur_val_level>=glue_val then
    begin if cur_val_level<>level then mu_error;
    return;
    end;
  if cur_val_level=int_val then scan_dimen(mu,false,true)
  else if level=mu_val then mu_error;
  end
else  begin back_input; scan_dimen(mu,false,false);
  if negative then negate(cur_val);
  end;
@<Create a new glue specification whose width is |cur_val|; scan for its
  stretch and shrink components@>;
exit:end;
@#
@<Declare procedures needed for expressions@>@;

@ @<Create a new glue specification whose width is |cur_val|...@>=
q:=new_spec(zero_glue); width(q):=cur_val;
if scan_keyword('plus') then
@.plus@>
  begin scan_dimen(mu,true,false);
  stretch(q):=cur_val; stretch_order(q):=cur_order;
  end;
if scan_keyword('minus') then
@.minus@>
  begin scan_dimen(mu,true,false);
  shrink(q):=cur_val; shrink_order(q):=cur_order;
  end;
cur_val:=q

@ Here's a similar procedure that returns a pointer to a rule node. This
routine is called just after \TeX\ has seen \.{\\hrule} or \.{\\vrule};
therefore |cur_cmd| will be either |hrule| or |vrule|. The idea is to store
the default rule dimensions in the node, then to override them if
`\.{height}' or `\.{width}' or `\.{depth}' specifications are
found (in any order).

@d default_rule=26214 {0.4\thinspace pt}

@p function scan_rule_spec:pointer;
label reswitch;
var q:pointer; {the rule node being created}
begin q:=new_rule; {|width|, |depth|, and |height| all equal |null_flag| now}
if cur_cmd=vrule then begin
  width(q):=default_rule;
  rule_dir(q):=body_direction;
  end
else begin
  height(q):=default_rule; depth(q):=0;
  rule_dir(q):=text_direction;
end;
reswitch: if scan_keyword('width') then
@.width@>
  begin scan_normal_dimen; width(q):=cur_val; goto reswitch;
  end;
if scan_keyword('height') then
@.height@>
  begin scan_normal_dimen; height(q):=cur_val; goto reswitch;
  end;
if scan_keyword('depth') then
@.depth@>
  begin scan_normal_dimen; depth(q):=cur_val; goto reswitch;
  end;
scan_rule_spec:=q;
end;

@* \[27] Building token lists.
The token lists for macros and for other things like \.{\\mark} and \.{\\output}
and \.{\\write} are produced by a procedure called |scan_toks|.

Before we get into the details of |scan_toks|, let's consider a much
simpler task, that of converting the current string into a token list.
The |str_toks| function does this; it classifies spaces as type |spacer|
and everything else as type |other_char|.

The token list created by |str_toks| begins at |link(temp_token_head)| and ends
at the value |p| that is returned. (If |p=temp_token_head|, the list is empty.)

|lua_str_toks| is almost identical, but it also escapes the three
symbols that |lua| considers special while scanning a literal string

@d unicode_incr(#)==if str_pool[#]>=@"F0 then #:=#+4 else if str_pool[#]>=@"E0
     then #:=#+3 else if str_pool[#]>=@"C0 then #:=#+2 else incr(#)


@p @t\4@>@<Declare \eTeX\ procedures for token lists@>@;@/
function lua_str_toks(@!b:pool_pointer):pointer;
  {changes the string |str_pool[b..pool_ptr]| to a token list}
var p:pointer; {tail of the token list}
@!q:pointer; {new node being added to the token list via |store_new_token|}
@!t:halfword; {token being appended}
@!k:pool_pointer; {index into |str_pool|}
begin
p:=temp_token_head; link(p):=null; k:=b;
while k<pool_ptr do
  begin t:=pool_to_unichar(k);
  if t=" " then t:=space_token
  else
    begin
     if (t="\") or (t="""") or (t="'") or (t=10) or (t=13) then
          fast_store_new_token(other_token+"\");
     if (t=10) then
       t:="n";
     if (t=13) then
       t:="r";
    t:=other_token+t;
    end;
  fast_store_new_token(t);
  unicode_incr(k);
  end;
pool_ptr:=b; lua_str_toks:=p;
end;

function str_toks(@!b:pool_pointer):pointer;
  {changes the string |str_pool[b..pool_ptr]| to a token list}
var p:pointer; {tail of the token list}
@!q:pointer; {new node being added to the token list via |store_new_token|}
@!t:halfword; {token being appended}
@!k:pool_pointer; {index into |str_pool|}
begin
p:=temp_token_head; link(p):=null; k:=b;
while k<pool_ptr do
  begin t:=pool_to_unichar(k);
  if t=" " then t:=space_token
  else t:=other_token+t;
  fast_store_new_token(t);
  unicode_incr(k);
  end;
pool_ptr:=b; str_toks:=p;
end;

@ The main reason for wanting |str_toks| is the next function,
|the_toks|, which has similar input/output characteristics.

This procedure is supposed to scan something like `\.{\\skip\\count12}',
i.e., whatever can follow `\.{\\the}', and it constructs a token list
containing something like `\.{-3.0pt minus 0.5fill}'.

@p function the_toks:pointer;
label exit;
var old_setting:0..max_selector; {holds |selector| setting}
@!p,@!q,@!r:pointer; {used for copying a token list}
@!b:pool_pointer; {base of temporary string}
@!c:small_number; {value of |cur_chr|}
begin @<Handle \.{\\unexpanded} or \.{\\detokenize} and |return|@>;@/
get_x_token; scan_something_internal(tok_val,false);
if cur_val_level>=ident_val then begin
  @<Copy the token list@>;
  the_toks:=p;
  end
else begin old_setting:=selector; selector:=new_string; b:=pool_ptr;
  case cur_val_level of
  int_val:print_int(cur_val);
  attr_val:print_int(cur_val);
  dir_val:print_dir(cur_val);
  dimen_val:begin print_scaled(cur_val); print("pt");
    end;
  glue_val: begin print_spec(cur_val,"pt"); delete_glue_ref(cur_val);
    end;
  mu_val: begin print_spec(cur_val,"mu"); delete_glue_ref(cur_val);
    end;
  end; {there are no other cases}
  selector:=old_setting; the_toks:=str_toks(b);
  end;
exit:end;

function the_scanned_result:str_number;
var old_setting:0..max_selector; {holds |selector| setting}
begin
old_setting:=selector; selector:=new_string;
if cur_val_level>=ident_val then begin
  if cur_val<>null then begin
    show_token_list(link(cur_val),null,pool_size-pool_ptr);
    the_scanned_result:=make_string;
    end
  else
    the_scanned_result:="";
  end
else begin
    case cur_val_level of
    int_val:print_int(cur_val);
    attr_val:print_int(cur_val);
    dir_val:print_dir(cur_val);
    dimen_val:begin print_scaled(cur_val); print("pt");
      end;
    glue_val: begin print_spec(cur_val,"pt"); delete_glue_ref(cur_val);
      end;
    mu_val: begin print_spec(cur_val,"mu"); delete_glue_ref(cur_val);
      end;
    end; {there are no other cases}
    the_scanned_result:=make_string;
  end;
selector:=old_setting;
end;

@ @<Copy the token list@>=
begin p:=temp_token_head; link(p):=null;
if cur_val_level=ident_val then store_new_token(cs_token_flag+cur_val)
else if cur_val<>null then
  begin r:=link(cur_val); {do not copy the reference count}
  while r<>null do
    begin fast_store_new_token(info(r)); r:=link(r);
    end;
  end;
end

@ Here's part of the |expand| subroutine that we are now ready to complete:

@p procedure ins_the_toks;
var junk:pointer;
begin junk:=the_toks; ins_list(link(temp_token_head));
end;

@ The primitives \.{\\number}, \.{\\romannumeral}, \.{\\string}, \.{\\meaning},
\.{\\fontname}, and \.{\\jobname} are defined as follows.

\eTeX\ adds \.{\\eTeXrevision} such that |job_name_code| remains last.

\pdfTeX\ adds \.{\\eTeXrevision}, \.{\\pdftexrevision}, \.{\\pdftexbanner},
\.{\\pdffontname}, \.{\\pdffontobjnum}, \.{\\pdffontsize}, and \.{\\pdfpageref}
such that |job_name_code| remains last.

@d number_code=0 {command code for \.{\\number}}
@d roman_numeral_code=1 {command code for \.{\\romannumeral}}
@d string_code=2 {command code for \.{\\string}}
@d meaning_code=3 {command code for \.{\\meaning}}
@d font_name_code=4 {command code for \.{\\fontname}}
@d etex_code=5 {command code for \.{\\eTeXVersion}}
@d omega_code=6 {command code for \.{\\OmegaVersion}}
@d aleph_code=7 {command code for \.{\\AlephVersion}}
@d format_name_code=8 {command code for \.{\\AlephVersion}}
@d pdftex_first_expand_code = 9 {base for \pdfTeX's command codes}
@d pdftex_revision_code     = pdftex_first_expand_code + 0 {command code for \.{\\pdftexrevision}}
@d pdftex_banner_code       = pdftex_first_expand_code + 1 {command code for \.{\\pdftexbanner}}
@d pdf_font_name_code       = pdftex_first_expand_code + 2 {command code for \.{\\pdffontname}}
@d pdf_font_objnum_code     = pdftex_first_expand_code + 3 {command code for \.{\\pdffontobjnum}}
@d pdf_font_size_code       = pdftex_first_expand_code + 4 {command code for \.{\\pdffontsize}}
@d pdf_page_ref_code        = pdftex_first_expand_code + 5 {command code for \.{\\pdfpageref}}
@d pdf_xform_name_code      = pdftex_first_expand_code + 6 {command code for \.{\\pdfxformname}}
@d left_margin_kern_code    = pdftex_first_expand_code + 7 {command code for \.{\\leftmarginkern}}
@d right_margin_kern_code   = pdftex_first_expand_code + 8 {command code for \.{\\rightmarginkern}}
@d pdf_creation_date_code   = pdftex_first_expand_code + 9 {command code for \.{\\pdfcreationdate}}
@d uniform_deviate_code     = pdftex_first_expand_code + 10 {command code for \.{\\uniformdeviate}}
@d normal_deviate_code      = pdftex_first_expand_code + 11 {command code for \.{\\normaldeviate}}
@d pdf_insert_ht_code       = pdftex_first_expand_code + 12 {command code for \.{\\pdfinsertht}}
@d pdf_ximage_bbox_code     = pdftex_first_expand_code + 13 {command code for \.{\\pdfximagebbox}}
@d lua_code                 = pdftex_first_expand_code + 14 {command code for \.{\\directlua}}
@d lua_escape_string_code   = pdftex_first_expand_code + 15 {command code for \.{\\luaescapestring}}
@d pdf_colorstack_init_code = pdftex_first_expand_code + 16 {command code for \.{\\pdfcolorstackinit}}
@d luatex_revision_code     = pdftex_first_expand_code + 17 {command code for \.{\\luatexrevision}}
@d luatex_date_code         = pdftex_first_expand_code + 18 {command code for \.{\\luatexdate}}
@d math_style_code          = pdftex_first_expand_code + 19 {command code for \.{\\mathstyle}}
@d expanded_code            = pdftex_first_expand_code + 20 {command code for \.{\\expanded}}
@d pdftex_convert_codes     = pdftex_first_expand_code + 21 {end of \pdfTeX's command codes}
@d job_name_code=pdftex_convert_codes {command code for \.{\\jobname}}


@<Put each...@>=
primitive_tex("number",convert,number_code,0);@/
@!@:number_}{\.{\\number} primitive@>
primitive_tex("romannumeral",convert,roman_numeral_code,0);@/
@!@:roman_numeral_}{\.{\\romannumeral} primitive@>
primitive_tex("string",convert,string_code,0);@/
@!@:string_}{\.{\\string} primitive@>
primitive_tex("meaning",convert,meaning_code,0);@/
@!@:meaning_}{\.{\\meaning} primitive@>
primitive_etex("eTeXVersion",convert,etex_code,0);@/
@!@:omega_version_}{\.{\\OmegaVersion} primitive@>
primitive_omega("OmegaVersion",convert,omega_code,0);@/
@!@:omega_version_}{\.{\\OmegaVersion} primitive@>
primitive_aleph("AlephVersion",convert,aleph_code,0);@/
@!@:aleph_version_}{\.{\\AlephVersion} primitive@>
primitive_tex("fontname",convert,font_name_code,0);@/
@!@:font_name_}{\.{\\fontname} primitive@>
primitive_pdftex("pdftexrevision",convert,pdftex_revision_code,0);@/
@!@:pdftex_revision_}{\.{\\pdftexrevision} primitive@>
primitive_luatex("luatexrevision",convert,luatex_revision_code,0);@/
@!@:luatex_revision_}{\.{\\luatexrevision} primitive@>
primitive_luatex("luatexdatestamp",convert,luatex_date_code,0);@/
@!@:luatex_date_}{\.{\\luatexdatestamp} primitive@>
primitive_pdftex("pdftexbanner",convert,pdftex_banner_code,0);@/
@!@:pdftex_banner_}{\.{\\pdftexbanner} primitive@>
primitive_pdftex("pdffontname",convert,pdf_font_name_code,0);@/
@!@:pdf_font_name_}{\.{\\pdffontname} primitive@>
primitive_pdftex("pdffontobjnum",convert,pdf_font_objnum_code,0);@/
@!@:pdf_font_objnum_}{\.{\\pdffontobjnum} primitive@>
primitive_pdftex("pdffontsize",convert,pdf_font_size_code,0);@/
@!@:pdf_font_size_}{\.{\\pdffontsize} primitive@>
primitive_pdftex("pdfpageref",convert,pdf_page_ref_code,0);@/
@!@:pdf_page_ref_}{\.{\\pdfpageref} primitive@>
primitive_pdftex("leftmarginkern",convert,left_margin_kern_code,0);@/
@!@:left_margin_kern_}{\.{\\leftmarginkern} primitive@>
primitive_pdftex("rightmarginkern",convert,right_margin_kern_code,0);@/
@!@:right_margin_kern_}{\.{\\rightmarginkern} primitive@>
primitive_pdftex("pdfxformname",convert,pdf_xform_name_code,0);@/
@!@:pdf_xform_name_}{\.{\\pdfxformname} primitive@>
primitive_pdftex("pdfcreationdate",convert,pdf_creation_date_code,0);@/
@!@:pdf_creation_date_}{\.{\\pdfcreationdate} primitive@>
primitive_pdftex("pdfuniformdeviate",convert,uniform_deviate_code,0);@/
@!@:uniform_deviate_}{\.{\\pdfuniformdeviate} primitive@>
primitive_pdftex("pdfcolorstackinit",convert,pdf_colorstack_init_code,0);@/
@!@:pdf_colorstack_init_}{\.{\\pdfcolorstackinit} primitive@>
primitive_pdftex("pdfnormaldeviate",convert,normal_deviate_code,0);@/
@!@:normal_deviate_}{\.{\\pdfnormaldeviate} primitive@>
primitive_core("directlua",convert,lua_code,0);@/
@!@:lua_}{\.{\\directlua} primitive@>
primitive_luatex("luaescapestring",convert,lua_escape_string_code,0);@/
@!@:lua_}{\.{\\luaescapestring} primitive@>
primitive_luatex("mathstyle",convert,math_style_code,0);@/
@!@:math_style_}{\.{\\mathstyle} primitive@>
primitive_pdftex("expanded",convert,expanded_code,0);@/
@!@:expanded_}{\.{\\expanded} primitive@>
@#
primitive_tex("jobname",convert,job_name_code,0);@/
@!@:job_name_}{\.{\\jobname} primitive@>
primitive_luatex("formatname",convert,format_name_code,0);@/
@!@:format_name_}{\.{\\formatname} primitive@>
primitive_pdftex("pdfinsertht",convert,pdf_insert_ht_code,0);@/
@!@:pdf_insert_ht_}{\.{\\pdfinsertht} primitive@>
primitive_pdftex("pdfximagebbox",convert,pdf_ximage_bbox_code,0);@/
@!@:pdf_ximage_bbox_}{\.{\\pdfximagebbox} primitive@>

@ The procedure |conv_toks| uses |str_toks| to insert the token list
for |convert| functions into the scanner; `\.{\\outer}' control sequences
are allowed to follow `\.{\\string}' and `\.{\\meaning}'.

The extra temp string |u| is needed because |pdf_scan_ext_toks| incorporates
any pending string in its output. In order to save such a pending string,
we have to create a temporary string that is destroyed immediately after.

@d save_cur_string==if str_start_macro(str_ptr)<pool_ptr then u:=make_string
@d restore_cur_string==if u<>0 then begin decr(str_ptr); u:=0; end

@p procedure conv_toks;
label exit;
var old_setting:0..max_selector; {holds |selector| setting}
p, q: pointer;
@!c:number_code..job_name_code; {desired type of conversion}
@!save_scanner_status:small_number; {|scanner_status| upon entry}
@!save_def_ref: pointer; {|def_ref| upon entry, important if inside `\.{\\message}'}
@!save_warning_index: pointer;
@!bool: boolean; {temp boolean}
@!i: integer; {first temp integer}
@!j: integer; {second temp integer}
@!b:pool_pointer; {base of temporary string}
@!s: str_number; {first temp string}
@!sn: integer; {lua chunk name}
@!u: str_number; {third temp string}
@!junk: pointer;
begin
c:=cur_chr;
u:=0; { will become non-nil if a string is already being built}
j:=0; i:=0;
@<Scan the argument for command |c|@>;
old_setting:=selector; selector:=new_string; b:=pool_ptr;
@<Print the result of command |c|@>;
selector:=old_setting; junk:=str_toks(b); ins_list(link(temp_token_head));
exit:
end;

@ @<Glob...@>=
in_lua_escape:boolean;

@ @<Set init...@>=
in_lua_escape:=false;

@ @<Scan the argument for command |c|@>=
case c of
number_code,roman_numeral_code: scan_int;
string_code, meaning_code: begin save_scanner_status:=scanner_status;
  scanner_status:=normal; get_token; scanner_status:=save_scanner_status;
  end;
etex_code: do_nothing;
omega_code: do_nothing;
aleph_code: do_nothing;
font_name_code: scan_font_ident;
pdftex_revision_code: do_nothing;
luatex_revision_code: do_nothing;
luatex_date_code: do_nothing;
pdftex_banner_code: do_nothing;
pdf_font_name_code, pdf_font_objnum_code, pdf_font_size_code: begin
    scan_font_ident;
    if cur_val = null_font then
        pdf_error("font", "invalid font identifier");
    if c <> pdf_font_size_code then begin
        pdf_check_vf_cur_val;
        if not font_used(cur_val) then
            pdf_init_font_cur_val;
    end;
end;
pdf_page_ref_code: begin
    scan_int;
    if cur_val <= 0 then
        pdf_error("pageref", "invalid page number");
end;
left_margin_kern_code, right_margin_kern_code: begin
    scan_int;
    if (box(cur_val) = null) or (type(box(cur_val)) <> hlist_node) then
        pdf_error("marginkern", "a non-empty hbox expected")
end;
pdf_xform_name_code: begin
    scan_int;
    pdf_check_obj(obj_type_xform, cur_val);
end;
pdf_creation_date_code:
  begin
    b := pool_ptr;
    getcreationdate;
    junk := str_toks(b);
    ins_list(link(temp_token_head));
    return;
  end;
job_name_code: if job_name=0 then open_log_file;
pdf_colorstack_init_code:
  begin
    bool := scan_keyword('page');
    if scan_keyword('direct') then
        cur_val := direct_always
    else
        if scan_keyword('page') then
            cur_val := direct_page
        else
            cur_val := set_origin;
    save_scanner_status := scanner_status;
    save_warning_index := warning_index;
    save_def_ref := def_ref;
    save_cur_string;
    scan_pdf_ext_toks;
    s := tokens_to_string(def_ref);
    delete_token_ref(def_ref);
    def_ref := save_def_ref;
    warning_index := save_warning_index;
    scanner_status := save_scanner_status;
    cur_val := newcolorstack(s, cur_val, bool);
    flush_str(s);
    cur_val_level := int_val;
    if cur_val < 0 then begin
        print_err("Too many color stacks");
@.Too many color stacks@>
        help2("The number of color stacks is limited to 32768.")@/
        ("I'll use the default color stack 0 here.");
        error;
        cur_val := 0;
       restore_cur_string;
    end;
  end;
uniform_deviate_code:     scan_int;
normal_deviate_code:      do_nothing;
lua_escape_string_code:
  begin
        u:=0;
    { check if a string is already being built}
    if str_start_macro(str_ptr)<pool_ptr then u:=make_string;
    save_scanner_status := scanner_status;
    save_def_ref := def_ref;
    save_warning_index := warning_index;
    scan_pdf_ext_toks;
    bool := in_lua_escape;
    in_lua_escape:=true;
    s := tokens_to_string(def_ref);
    in_lua_escape:=bool;
    delete_token_ref(def_ref);
    def_ref := save_def_ref;
    warning_index := save_warning_index;
    scanner_status := save_scanner_status;
    junk := lua_str_toks(str_start_macro(s));
        ins_list(link(temp_token_head));
    flush_str(s);
        if u<>0 then begin decr(str_ptr); u:=0; end;
    return;
  end;
math_style_code:  do_nothing;
expanded_code:
  begin
    save_scanner_status := scanner_status;
    save_warning_index := warning_index;
    save_def_ref := def_ref;
    save_cur_string;
    scan_pdf_ext_toks;
    warning_index := save_warning_index;
    scanner_status := save_scanner_status;
    ins_list(link(def_ref));
    def_ref := save_def_ref;
    restore_cur_string;
    return;
  end;
lua_code:
  begin
    u:=0;
    { Have to check if a string is already being built, because lua code
      may call library functions that may call C functions that
      themselves use the string pool, like e.g. |maketexstring| }
    if str_start_macro(str_ptr)<pool_ptr then u:=make_string;
    save_scanner_status := scanner_status;
    save_def_ref := def_ref;
    save_warning_index := warning_index;
    sn:=0;
    if scan_keyword('name') then begin
       scan_pdf_ext_toks;
       sn := def_ref;
    end;
    @<Parse optional lua state integer, or an instance name to be stored in |sn|@>;
    scan_pdf_ext_toks;
    s := def_ref;
    warning_index := save_warning_index;
    def_ref := save_def_ref;
    scanner_status := save_scanner_status;
    luacstrings:=0;
    luatokencall(s,sn);
    delete_token_ref(s);
    if u<>0 then begin
      if str_ptr=u+1 then
        decr(str_ptr)
      else begin {copy old string to the top location}
         i:=0;
             str_room(length(u));
         while i<length(u) do
           str_pool[pool_ptr+i]:=str_pool[str_start_macro(u)+i];
        end;
    end;
    if luacstrings>0 then
      lua_string_start;
    return;
  end;
pdf_insert_ht_code: scan_register_num;
pdf_ximage_bbox_code: begin
    scan_int;
    pdf_check_obj(obj_type_ximage, cur_val);
    i := obj_data_ptr(cur_val);
    scan_int;
    j := cur_val;
    if (j < 1) or (j > 4) then
        pdf_error("pdfximagebbox", "invalid parameter");
    end;
@<Cases of `Scan the argument for command |c|'@>
end {there are no other cases}

@ @<Parse optional lua state...@>=
begin
    @<Get the next non-blank non-relax non-call token@>;
    back_input; { have to push it back, whatever it is }
    if cur_cmd<>left_brace then begin
      scan_register_num;
      if get_lua_name(cur_val) then
        sn:=(cur_val-65536)
      else begin
        i:=tracing_online;
        tracing_online:=1;
        begin_diagnostic;
        print_nl("Warning: support for multiple lua states has been dropped.");
        print_nl("  Please stop using a number after \directlua and \latelua.");
        end_diagnostic(true);
        tracing_online:=i;
        end;
      end;
end

@ @<Print the result of command |c|@>=
case c of
number_code: print_int(cur_val);
roman_numeral_code: print_roman_int(cur_val);
string_code:if cur_cs<>0 then sprint_cs(cur_cs)
  else print(cur_chr);
meaning_code: print_meaning;
etex_code: print(eTeX_version_string);
omega_code: print(Omega_version_string);
aleph_code: print(Aleph_version_string);
font_name_code: begin
  append_string(font_name(cur_val));
  if font_size(cur_val)<>font_dsize(cur_val) then
    begin print(" at "); print_scaled(font_size(cur_val));
    print("pt");
    end;
  end;
pdftex_revision_code: print(pdftex_revision);
luatex_revision_code: print(luatex_revision);
luatex_date_code:   print_int(luatex_date_info);
pdftex_banner_code: print(pdftex_banner);
pdf_font_name_code, pdf_font_objnum_code: begin
    set_ff(cur_val);
    if c = pdf_font_name_code then
        print_int(obj_info(pdf_font_num(ff)))
    else
        print_int(pdf_font_num(ff));
end;
pdf_font_size_code: begin
    print_scaled(font_size(cur_val));
    print("pt");
end;
pdf_page_ref_code: print_int(get_obj(obj_type_page, cur_val, false));
left_margin_kern_code: begin
    p := list_ptr(box(cur_val));
    if (p <> null) and (not is_char_node(p)) and
       (type(p) = glue_node) and (subtype(p) = left_skip_code + 1) then
       p := vlink(p);
    if (p <> null) and (not is_char_node(p)) and
       (type(p) = margin_kern_node) and (subtype(p) = left_side) then
        print_scaled(width(p))
    else
        print("0");
    print("pt");
end;
right_margin_kern_code: begin
    q := list_ptr(box(cur_val));
    p := null;
    if q <> null then begin
        p := prev_rightmost(q, null);
        if (p <> null) and (not is_char_node(p)) and
           (type(p) = glue_node) and (subtype(p) = right_skip_code + 1) then
           p := prev_rightmost(q, p);
    end;
    if (p <> null) and (not is_char_node(p)) and
       (type(p) = margin_kern_node) and (subtype(p) = right_side) then
        print_scaled(width(p))
    else
        print("0");
    print("pt");
end;
pdf_xform_name_code: print_int(obj_info(cur_val));
pdf_colorstack_init_code: print_int(cur_val);
uniform_deviate_code:     print_int(unif_rand(cur_val));
normal_deviate_code:      print_int(norm_rand);
math_style_code:          print_math_style;
pdf_insert_ht_code: begin
    i := qi(cur_val);
    p := page_ins_head;
    while i >= subtype(vlink(p)) do
        p := vlink(p);
    if subtype(p) = i then
        print_scaled(height(p))
    else
        print("0");
    print("pt");
end;
pdf_ximage_bbox_code: begin
    if is_pdf_image(i) then begin
        case j of
        1: print_scaled(epdf_orig_x(i));
        2: print_scaled(epdf_orig_y(i));
        3: print_scaled(epdf_orig_x(i) + epdf_xsize(i));
        4: print_scaled(epdf_orig_y(i) + epdf_ysize(i));
        endcases;
    end else
        print_scaled(0);
    print("pt");
end;
format_name_code: print(format_name);
job_name_code: print(job_name);
@/@<Cases of `Print the result of command |c|'@>@/
end {there are no other cases}

@
@p function is_convert(c:halfword):boolean;
begin
  is_convert:=(c=convert);
end;

function the_convert_string (c:halfword;i:integer):str_number;
var old_setting:0..max_selector; {saved |selector| setting}
        is_known:boolean;
begin
  old_setting:=selector;
  selector:=new_string;
  is_known:=true;
  case c of
  number_code:            print_int(i);
  roman_numeral_code:     print_roman_int(i);
  etex_code:              print(eTeX_version_string);
  omega_code:             print(Omega_version_string);
  aleph_code:             print(Aleph_version_string);
  pdftex_revision_code:   print(pdftex_revision);
  luatex_revision_code:   print(luatex_revision);
  luatex_date_code:       print_int(luatex_date_info);
  pdftex_banner_code:     print(pdftex_banner);
  normal_deviate_code:    print_int(norm_rand);
  uniform_deviate_code:   print_int(unif_rand(i));
  format_name_code:       print(format_name);
  job_name_code:          print(job_name);
  math_style_code:        print_math_style;
  font_name_code: begin
    append_string(font_name(i));
    if font_size(i)<>font_dsize(i) then
      begin print(" at "); print_scaled(font_size(i));
      print("pt");
      end;
    end;
  font_identifier_code:   print_font_identifier(i);
  pdf_page_ref_code:      print_int(get_obj(obj_type_page, i, false));
  pdf_xform_name_code:    print_int(obj_info(i));
  pdf_font_name_code, pdf_font_objnum_code: begin
    set_ff(i);
    if c = pdf_font_name_code then
        print_int(obj_info(pdf_font_num(ff)))
    else
        print_int(pdf_font_num(ff));
    end;
  pdf_font_size_code: begin
    print_scaled(font_size(i));
    print("pt");
  end;

@/@<Cases of `Print the result of command |c|'@>@/
  othercases            is_known:=false
  end;
  if is_known then
    the_convert_string := make_string
  else
    the_convert_string := 0;
  selector:=old_setting;
end;

@ Now we can't postpone the difficulties any longer; we must bravely tackle
|scan_toks|. This function returns a pointer to the tail of a new token
list, and it also makes |def_ref| point to the reference count at the
head of that list.

There are two boolean parameters, |macro_def| and |xpand|. If |macro_def|
is true, the goal is to create the token list for a macro definition;
otherwise the goal is to create the token list for some other \TeX\
primitive: \.{\\mark}, \.{\\output}, \.{\\everypar}, \.{\\lowercase},
\.{\\uppercase}, \.{\\message}, \.{\\errmessage}, \.{\\write}, or
\.{\\special}. In the latter cases a left brace must be scanned next; this
left brace will not be part of the token list, nor will the matching right
brace that comes at the end. If |xpand| is false, the token list will
simply be copied from the input using |get_token|. Otherwise all expandable
tokens will be expanded until unexpandable tokens are left, except that
the results of expanding `\.{\\the}' are not expanded further.
If both |macro_def| and |xpand| are true, the expansion applies
only to the macro body (i.e., to the material following the first
|left_brace| character).

The value of |cur_cs| when |scan_toks| begins should be the |eqtb|
address of the control sequence to display in ``runaway'' error
messages.

@p function scan_toks(@!macro_def,@!xpand:boolean):pointer;
label found,done,done1,done2;
var t:halfword; {token representing the highest parameter number}
@!s:halfword; {saved token}
@!p:pointer; {tail of the token list being built}
@!q:pointer; {new node being added to the token list via |store_new_token|}
@!unbalance:halfword; {number of unmatched left braces}
@!hash_brace:halfword; {possible `\.{\#\{}' token}
begin if macro_def then scanner_status:=defining
@+else scanner_status:=absorbing;
warning_index:=cur_cs; p:=get_avail; def_ref:=p; token_ref_count(def_ref):=0;
p:=def_ref; hash_brace:=0; t:=zero_token;
if macro_def then @<Scan and build the parameter part of the macro definition@>
else scan_left_brace; {remove the compulsory left brace}
@<Scan and build the body of the token list; |goto found| when finished@>;
found: scanner_status:=normal;
if hash_brace<>0 then store_new_token(hash_brace);
scan_toks:=p;
end;

@ @<Scan and build the parameter part...@>=
begin loop begin get_token; {set |cur_cmd|, |cur_chr|, |cur_tok|}
  if cur_tok<right_brace_limit then goto done1;
  if cur_cmd=mac_param then
    @<If the next character is a parameter number, make |cur_tok|
      a |match| token; but if it is a left brace, store
      `|left_brace|, |end_match|', set |hash_brace|, and |goto done|@>;
  store_new_token(cur_tok);
  end;
done1: store_new_token(end_match_token);
if cur_cmd=right_brace then
  @<Express shock at the missing left brace; |goto found|@>;
done: end

@ @<Express shock...@>=
begin print_err("Missing { inserted"); incr(align_state);
@.Missing \{ inserted@>
help2("Where was the left brace? You said something like `\def\a}',")@/
  ("which I'm going to interpret as `\def\a{}'."); error; goto found;
end

@ @<If the next character is a parameter number...@>=
begin s:=match_token+cur_chr; get_token;
if cur_cmd=left_brace then
  begin hash_brace:=cur_tok;
  store_new_token(cur_tok); store_new_token(end_match_token);
  goto done;
  end;
if t=zero_token+9 then
  begin print_err("You already have nine parameters");
@.You already have nine...@>
  help1("I'm going to ignore the # sign you just used."); error;
  end
else  begin incr(t);
  if cur_tok<>t then
    begin print_err("Parameters must be numbered consecutively");
@.Parameters...consecutively@>
    help2("I've inserted the digit you should have used after the #.")@/
      ("Type `1' to delete what you did use."); back_error;
    end;
  cur_tok:=s;
  end;
end

@ @<Scan and build the body of the token list; |goto found| when finished@>=
unbalance:=1;
loop@+  begin if xpand then @<Expand the next part of the input@>
  else get_token;
  if cur_tok<right_brace_limit then begin
    if cur_cmd<right_brace then incr(unbalance)
    else  begin decr(unbalance);
      if unbalance=0 then goto found;
      end;
    end
  else if cur_cmd=mac_param then
    if macro_def then @<Look for parameter number or \.{\#\#}@>;
  store_new_token(cur_tok);
  end

@ Here we insert an entire token list created by |the_toks| without
expanding it further.

@<Expand the next part of the input@>=
begin loop begin get_filtered_next;
  if cur_cmd>=call then
    if info(link(cur_chr))=protected_token then
      begin cur_cmd:=relax; cur_chr:=no_expand_flag;
      end;
  if cur_cmd<=max_command then goto done2;
  if cur_cmd<>the then expand
  else  begin q:=the_toks;
    if link(temp_token_head)<>null then
      begin link(p):=link(temp_token_head); p:=q;
      end;
    end;
  end;
done2: x_token
end

@ @<Look for parameter number...@>=
begin s:=cur_tok;
if xpand then get_x_token else get_token;
if cur_cmd<>mac_param then begin
  if (cur_tok<=zero_token)or(cur_tok>t) then
    begin print_err("Illegal parameter number in definition of ");
@.Illegal parameter number...@>
    sprint_cs(warning_index);
    help3("You meant to type ## instead of #, right?")@/
    ("Or maybe a } was forgotten somewhere earlier, and things")@/
    ("are all screwed up? I'm going to assume that you meant ##.");
    back_error; cur_tok:=s;
    end
  else cur_tok:=out_param_token-"0"+cur_chr;
  end;
end

@ Another way to create a token list is via the \.{\\read} command. The
sixteen files potentially usable for reading appear in the following
global variables. The value of |read_open[n]| will be |closed| if
stream number |n| has not been opened or if it has been fully read;
|just_open| if an \.{\\openin} but not a \.{\\read} has been done;
and |normal| if it is open and ready to read the next line.

@d closed=2 {not open, or at end of file}
@d just_open=1 {newly opened, first line not yet read}

@<Glob...@>=
@!read_file:array[0..15] of alpha_file; {used for \.{\\read}}
@!read_open:array[0..16] of normal..closed; {state of |read_file[n]|}

@ @<Set init...@>=
for k:=0 to 16 do begin
    read_open[k]:=closed;
end;

@ The |read_toks| procedure constructs a token list like that for any
macro definition, and makes |cur_val| point to it. Parameter |r| points
to the control sequence that will receive this token list.

@p procedure read_toks(@!n:integer;@!r:pointer;@!j:halfword);
label done;
var p:pointer; {tail of the token list}
@!q:pointer; {new node being added to the token list via |store_new_token|}
@!s:integer; {saved value of |align_state|}
@!m:small_number; {stream number}
begin scanner_status:=defining; warning_index:=r;
p:=get_avail; def_ref:=p; token_ref_count(def_ref):=0;
p:=def_ref; {the reference count}
store_new_token(end_match_token);
if (n<0)or(n>15) then m:=16@+else m:=n;
s:=align_state; align_state:=1000000; {disable tab marks, etc.}
repeat @<Input and store tokens from the next line of the file@>;
until align_state=1000000;
cur_val:=def_ref; scanner_status:=normal; align_state:=s;
end;

@ @<Input and store tokens from the next line of the file@>=
begin_file_reading; name:=m+1;
if read_open[m]=closed then @<Input for \.{\\read} from the terminal@>
else if read_open[m]=just_open then @<Input the first line of |read_file[m]|@>
else @<Input the next line of |read_file[m]|@>;
limit:=last;
if end_line_char_inactive then decr(limit)
else  buffer[limit]:=end_line_char;
first:=limit+1; loc:=start; state:=new_line;@/
@<Handle \.{\\readline} and |goto done|@>;@/
loop@+  begin get_token;
  if cur_tok=0 then goto done;
    {|cur_cmd=cur_chr=0| will occur at the end of the line}
  if align_state<1000000 then {unmatched `\.\}' aborts the line}
    begin repeat get_token; until cur_tok=0;
    align_state:=1000000; goto done;
    end;
  store_new_token(cur_tok);
  end;
done: end_file_reading

@ Here we input on-line into the |buffer| array, prompting the user explicitly
if |n>=0|.  The value of |n| is set negative so that additional prompts
will not be given in the case of multi-line input.

@<Input for \.{\\read} from the terminal@>=
if interaction>nonstop_mode then
  if n<0 then prompt_input("")
  else  begin wake_up_terminal;
    print_ln; sprint_cs(r); prompt_input("="); n:=-1;
    end
else fatal_error("*** (cannot \read from terminal in nonstop modes)")
@.cannot \\read@>

@ The first line of a file must be treated specially, since |lua_input_ln|
must be told not to start with |get|.
@^system dependencies@>

@<Input the first line of |read_file[m]|@>=
begin if lua_input_ln(read_file[m],(m+1),false) then read_open[m]:=normal
else  begin lua_a_close_in(read_file[m],(m+1)); read_open[m]:=closed;
  end;
end

@ An empty line is appended at the end of a |read_file|.
@^empty line at end of file@>

@<Input the next line of |read_file[m]|@>=
begin if not lua_input_ln(read_file[m],(m+1),true) then
  begin lua_a_close_in(read_file[m],(m+1)); read_open[m]:=closed;
  if align_state<>1000000 then
    begin runaway;
    print_err("File ended within "); print_esc("read");
@.File ended within \\read@>
    help1("This \read has unbalanced braces.");
    align_state:=1000000; error;
    end;
  end;
end

@* \[28] Conditional processing.
We consider now the way \TeX\ handles various kinds of \.{\\if} commands.

@d unless_code=32 {amount added for `\.{\\unless}' prefix}
@#
@d if_char_code=0 { `\.{\\if}' }
@d if_cat_code=1 { `\.{\\ifcat}' }
@d if_int_code=2 { `\.{\\ifnum}' }
@d if_dim_code=3 { `\.{\\ifdim}' }
@d if_odd_code=4 { `\.{\\ifodd}' }
@d if_vmode_code=5 { `\.{\\ifvmode}' }
@d if_hmode_code=6 { `\.{\\ifhmode}' }
@d if_mmode_code=7 { `\.{\\ifmmode}' }
@d if_inner_code=8 { `\.{\\ifinner}' }
@d if_void_code=9 { `\.{\\ifvoid}' }
@d if_hbox_code=10 { `\.{\\ifhbox}' }
@d if_vbox_code=11 { `\.{\\ifvbox}' }
@d ifx_code=12 { `\.{\\ifx}' }
@d if_eof_code=13 { `\.{\\ifeof}' }
@d if_true_code=14 { `\.{\\iftrue}' }
@d if_false_code=15 { `\.{\\iffalse}' }
@d if_case_code=16 { `\.{\\ifcase}' }
@d if_primitive_code=21 { `\.{\\ifprimitive}' }

@<Put each...@>=
primitive_tex("if",if_test,if_char_code,0);
@!@:if_char_}{\.{\\if} primitive@>
primitive_tex("ifcat",if_test,if_cat_code,0);
@!@:if_cat_code_}{\.{\\ifcat} primitive@>
primitive_tex("ifnum",if_test,if_int_code,0);
@!@:if_int_}{\.{\\ifnum} primitive@>
primitive_tex("ifdim",if_test,if_dim_code,0);
@!@:if_dim_}{\.{\\ifdim} primitive@>
primitive_tex("ifodd",if_test,if_odd_code,0);
@!@:if_odd_}{\.{\\ifodd} primitive@>
primitive_tex("ifvmode",if_test,if_vmode_code,0);
@!@:if_vmode_}{\.{\\ifvmode} primitive@>
primitive_tex("ifhmode",if_test,if_hmode_code,0);
@!@:if_hmode_}{\.{\\ifhmode} primitive@>
primitive_tex("ifmmode",if_test,if_mmode_code,0);
@!@:if_mmode_}{\.{\\ifmmode} primitive@>
primitive_tex("ifinner",if_test,if_inner_code,0);
@!@:if_inner_}{\.{\\ifinner} primitive@>
primitive_tex("ifvoid",if_test,if_void_code,0);
@!@:if_void_}{\.{\\ifvoid} primitive@>
primitive_tex("ifhbox",if_test,if_hbox_code,0);
@!@:if_hbox_}{\.{\\ifhbox} primitive@>
primitive_tex("ifvbox",if_test,if_vbox_code,0);
@!@:if_vbox_}{\.{\\ifvbox} primitive@>
primitive_tex("ifx",if_test,ifx_code,0);
@!@:ifx_}{\.{\\ifx} primitive@>
primitive_tex("ifeof",if_test,if_eof_code,0);
@!@:if_eof_}{\.{\\ifeof} primitive@>
primitive_tex("iftrue",if_test,if_true_code,0);
@!@:if_true_}{\.{\\iftrue} primitive@>
primitive_tex("iffalse",if_test,if_false_code,0);
@!@:if_false_}{\.{\\iffalse} primitive@>
primitive_tex("ifcase",if_test,if_case_code,0);
@!@:if_case_}{\.{\\ifcase} primitive@>
primitive_luatex("ifprimitive",if_test,if_primitive_code,0);
@!@:if_primitive_}{\.{\\ifprimitive} primitive@>
primitive_pdftex("ifpdfprimitive",if_test,if_primitive_code,0);
@!@:if_primitive_}{\.{\\ifpdfprimitive} primitive@>

@ Conditions can be inside conditions, and this nesting has a stack
that is independent of the |save_stack|.

Four global variables represent the top of the condition stack:
|cond_ptr| points to pushed-down entries, if any; |if_limit| specifies
the largest code of a |fi_or_else| command that is syntactically legal;
|cur_if| is the name of the current type of conditional; and |if_line|
is the line number at which it began.

If no conditions are currently in progress, the condition stack has the
special state |cond_ptr=null|, |if_limit=normal|, |cur_if=0|, |if_line=0|.
Otherwise |cond_ptr| points to a two-word node; the |type|, |subtype|, and
|link| fields of the first word contain |if_limit|, |cur_if|, and
|cond_ptr| at the next level, and the second word contains the
corresponding |if_line|.

@d if_limit_subtype(#)==subtype(#+1)
@d if_limit_type(#)==type(#+1)
@d if_line_field(#)==vlink(#+1)
@d if_code=1 {code for \.{\\if...} being evaluated}
@d fi_code=2 {code for \.{\\fi}}
@d else_code=3 {code for \.{\\else}}
@d or_code=4 {code for \.{\\or}}

@<Glob...@>=
@!cond_ptr:pointer; {top of the condition stack}
@!if_limit:normal..or_code; {upper bound on |fi_or_else| codes}
@!cur_if:small_number; {type of conditional being worked on}
@!if_line:integer; {line where that conditional began}

@ @<Set init...@>=
cond_ptr:=null; if_limit:=normal; cur_if:=0; if_line:=0;

@ @<Put each...@>=
primitive_tex("fi",fi_or_else,fi_code,0);
@!@:fi_}{\.{\\fi} primitive@>
text(frozen_fi):="fi"; eqtb[frozen_fi]:=eqtb[cur_val];
primitive_tex("or",fi_or_else,or_code,0);
@!@:or_}{\.{\\or} primitive@>
primitive_tex("else",fi_or_else,else_code,0);
@!@:else_}{\.{\\else} primitive@>

@ When we skip conditional text, we keep track of the line number
where skipping began, for use in error messages.

@<Glob...@>=
@!skip_line:integer; {skipping began here}

@ Here is a procedure that ignores text until coming to an \.{\\or},
\.{\\else}, or \.{\\fi} at level zero of $\.{\\if}\ldots\.{\\fi}$
nesting. After it has acted, |cur_chr| will indicate the token that
was found, but |cur_tok| will not be set (because this makes the
procedure run faster).

@p procedure pass_text;
label done;
var l:integer; {level of $\.{\\if}\ldots\.{\\fi}$ nesting}
@!save_scanner_status:small_number; {|scanner_status| upon entry}
begin save_scanner_status:=scanner_status; scanner_status:=skipping; l:=0;
skip_line:=line;
loop@+  begin get_filtered_next;
  if cur_cmd=fi_or_else then
    begin if l=0 then goto done;
    if cur_chr=fi_code then decr(l);
    end
  else if cur_cmd=if_test then incr(l);
  end;
done: scanner_status:=save_scanner_status;
if tracing_ifs>0 then show_cur_cmd_chr;
end;

@ When we begin to process a new \.{\\if}, we set |if_limit:=if_code|; then
if\/ \.{\\or} or \.{\\else} or \.{\\fi} occurs before the current \.{\\if}
condition has been evaluated, \.{\\relax} will be inserted.
For example, a sequence of commands like `\.{\\ifvoid1\\else...\\fi}'
would otherwise require something after the `\.1'.

@<Push the condition stack@>=
begin p:=new_node(if_node,0); vlink(p):=cond_ptr;
if_limit_type(p):=if_limit;
if_limit_subtype(p):=cur_if;
if_line_field(p):=if_line;
cond_ptr:=p; cur_if:=cur_chr; if_limit:=if_code; if_line:=line;
end

@ @<Pop the condition stack@>=
begin if if_stack[in_open]=cond_ptr then if_warning;
  {conditionals possibly not properly nested with files}
p:=cond_ptr;
if_line:=if_line_field(p);
cur_if:=if_limit_subtype(p);
if_limit:=if_limit_type(p);
cond_ptr:=vlink(p);
flush_node(p);
end

@ Here's a procedure that changes the |if_limit| code corresponding to
a given value of |cond_ptr|.

@p procedure change_if_limit(@!l:small_number;@!p:pointer);
label exit;
var q:pointer;
begin if p=cond_ptr then if_limit:=l {that's the easy case}
else  begin q:=cond_ptr;
  loop@+  begin if q=null then confusion("if");
@:this can't happen if}{\quad if@>
    if vlink(q)=p then
      begin if_limit_type(q):=l; return;
      end;
    q:=vlink(q);
    end;
  end;
exit:end;

@ A condition is started when the |expand| procedure encounters
an |if_test| command; in that case |expand| reduces to |conditional|,
which is a recursive procedure.
@^recursion@>

@p procedure conditional;
label exit,common_ending;
var b:boolean; {is the condition true?}
@!r:"<"..">"; {relation to be evaluated}
@!m,@!n,@!s:integer; {to be tested against the second operand}
@!p,@!q:pointer; {for traversing token lists in \.{\\ifx} tests}
@!save_scanner_status:small_number; {|scanner_status| upon entry}
@!save_cond_ptr:pointer; {|cond_ptr| corresponding to this conditional}
@!this_if:small_number; {type of this conditional}
@!is_unless:boolean; {was this if preceded by `\.{\\unless}' ?}
begin b:= false; {default is false, just in case}
if tracing_ifs>0 then if tracing_commands<=1 then show_cur_cmd_chr;
@<Push the condition stack@>;@+save_cond_ptr:=cond_ptr;
is_unless:=(cur_chr>=unless_code); this_if:=cur_chr mod unless_code;@/
@<Either process \.{\\ifcase} or set |b| to the value of a boolean condition@>;
if is_unless then b:=not b;
if tracing_commands>1 then @<Display the value of |b|@>;
if b then
  begin change_if_limit(else_code,save_cond_ptr);
  return; {wait for \.{\\else} or \.{\\fi}}
  end;
@<Skip to \.{\\else} or \.{\\fi}, then |goto common_ending|@>;
common_ending: if cur_chr=fi_code then @<Pop the condition stack@>
else if_limit:=fi_code; {wait for \.{\\fi}}
exit:end;

@ In a construction like `\.{\\if\\iftrue abc\\else d\\fi}', the first
\.{\\else} that we come to after learning that the \.{\\if} is false is
not the \.{\\else} we're looking for. Hence the following curious
logic is needed.

@ @<Skip to \.{\\else} or \.{\\fi}...@>=
loop@+  begin pass_text;
  if cond_ptr=save_cond_ptr then
    begin if cur_chr<>or_code then goto common_ending;
    print_err("Extra "); print_esc("or");
@.Extra \\or@>
    help1("I'm ignoring this; it doesn't match any \if.");
    error;
    end
  else if cur_chr=fi_code then @<Pop the condition stack@>;
  end

@ @<Either process \.{\\ifcase} or set |b|...@>=
case this_if of
if_char_code, if_cat_code: @<Test if two characters match@>;
if_int_code, if_dim_code: @<Test relation between integers or dimensions@>;
if_odd_code: @<Test if an integer is odd@>;
if_vmode_code: b:=(abs(mode)=vmode);
if_hmode_code: b:=(abs(mode)=hmode);
if_mmode_code: b:=(abs(mode)=mmode);
if_inner_code: b:=(mode<0);
if_void_code, if_hbox_code, if_vbox_code: @<Test box register status@>;
ifx_code: @<Test if two tokens match@>;
if_eof_code: begin scan_four_bit_int; b:=(read_open[cur_val]=closed);
  end;
if_true_code: b:=true;
if_false_code: b:=false;
@/@<Cases for |conditional|@>@/
if_case_code: @<Select the appropriate case
  and |return| or |goto common_ending|@>;
if_primitive_code: begin
  save_scanner_status:=scanner_status;
  scanner_status:=normal;
  get_filtered_next;
  scanner_status:=save_scanner_status;
  m := prim_lookup(text(cur_cs));
  b :=((cur_cmd<>undefined_cs) and
       (m<>undefined_primitive) and
       (cur_cmd=get_prim_eq_type(m)) and
       (cur_chr=get_prim_equiv(m)));
  end;
{there are no other cases, but for -Wall: }
othercases
  b:=false;
endcases

@ @<Display the value of |b|@>=
begin begin_diagnostic;
if b then print("{true}")@+else print("{false}");
end_diagnostic(false);
end

@ Here we use the fact that |"<"|, |"="|, and |">"| are consecutive ASCII
codes.
@^ASCII code@>

@<Test relation between integers or dimensions@>=
begin if this_if=if_int_code then scan_int@+else scan_normal_dimen;
n:=cur_val; @<Get the next non-blank non-call...@>;
if (cur_tok>=other_token+"<")and(cur_tok<=other_token+">") then
  r:=cur_tok-other_token
else  begin print_err("Missing = inserted for ");
@.Missing = inserted@>
  print_cmd_chr(if_test,this_if);
  help1("I was expecting to see `<', `=', or `>'. Didn't.");
  back_error; r:="=";
  end;
if this_if=if_int_code then scan_int@+else scan_normal_dimen;
case r of
"<": b:=(n<cur_val);
"=": b:=(n=cur_val);
">": b:=(n>cur_val);
othercases b:=false; {can't happen}
end;
end

@ @<Test if an integer is odd@>=
begin scan_int; b:=odd(cur_val);
end

@ @<Test box register status@>=
begin scan_register_num; p:=box(cur_val);
if this_if=if_void_code then b:=(p=null)
else if p=null then b:=false
else if this_if=if_hbox_code then b:=(type(p)=hlist_node)
else b:=(type(p)=vlist_node);
end

@ An active character will be treated as category 13 following
\.{\\if\\noexpand} or following \.{\\ifcat\\noexpand}.

@d get_x_token_or_active_char==@t@>@;
  begin get_x_token;
  if cur_cmd=relax then if cur_chr=no_expand_flag then if is_active_csname(cur_cs) then
    begin cur_cmd:=active_char;
    cur_chr:=active_csname_value(cur_tok-cs_token_flag);
    end;
  end

@<Test if two characters match@>=
begin get_x_token_or_active_char;
if (cur_cmd>active_char)or(cur_chr>biggest_char) then {not a character}
  begin m:=relax; n:=too_big_char;
  end
else  begin m:=cur_cmd; n:=cur_chr;
  end;
get_x_token_or_active_char;
if (cur_cmd>active_char)or(cur_chr>biggest_char) then
  begin cur_cmd:=relax; cur_chr:=too_big_char;
  end;
if this_if=if_char_code then b:=(n=cur_chr)@+else b:=(m=cur_cmd);
end

@ Note that `\.{\\ifx}' will declare two macros different if one is \\{long}
or \\{outer} and the other isn't, even though the texts of the macros are
the same.

We need to reset |scanner_status|, since \.{\\outer} control sequences
are allowed, but we might be scanning a macro definition or preamble.

@<Test if two tokens match@>=
begin save_scanner_status:=scanner_status; scanner_status:=normal;
get_filtered_next; n:=cur_cs; p:=cur_cmd; q:=cur_chr;
get_filtered_next; if cur_cmd<>p then b:=false
else if cur_cmd<call then b:=(cur_chr=q)
else @<Test if two macro texts match@>;
scanner_status:=save_scanner_status;
end

@ Note also that `\.{\\ifx}' decides that macros \.{\\a} and \.{\\b} are
different in examples like this:
$$\vbox{\halign{\.{#}\hfil&\qquad\.{#}\hfil\cr
  {}\\def\\a\{\\c\}&
  {}\\def\\c\{\}\cr
  {}\\def\\b\{\\d\}&
  {}\\def\\d\{\}\cr}}$$

@<Test if two macro texts match@>=
begin p:=link(cur_chr); q:=link(equiv(n)); {omit reference counts}
if p=q then b:=true
else begin while (p<>null)and(q<>null) do
    if info(p)<>info(q) then p:=null
    else  begin p:=link(p); q:=link(q);
      end;
  b:=((p=null)and(q=null));
  end;
end

@ @<Select the appropriate case and |return| or |goto common_ending|@>=
begin scan_int; n:=cur_val; {|n| is the number of cases to pass}
if tracing_commands>1 then
  begin begin_diagnostic; print("{case "); print_int(n); print_char("}");
  end_diagnostic(false);
  end;
while n<>0 do
  begin pass_text;
  if cond_ptr=save_cond_ptr then
    if cur_chr=or_code then decr(n)
    else goto common_ending
  else if cur_chr=fi_code then @<Pop the condition stack@>;
  end;
change_if_limit(or_code,save_cond_ptr);
return; {wait for \.{\\or}, \.{\\else}, or \.{\\fi}}
end

@ The processing of conditionals is complete except for the following
code, which is actually part of |expand|. It comes into play when
\.{\\or}, \.{\\else}, or \.{\\fi} is scanned.

@<Terminate the current conditional and skip to \.{\\fi}@>=
begin if tracing_ifs>0 then if tracing_commands<=1 then show_cur_cmd_chr;
if cur_chr>if_limit then
  if if_limit=if_code then insert_relax {condition not yet evaluated}
  else  begin print_err("Extra "); print_cmd_chr(fi_or_else,cur_chr);
@.Extra \\or@>
@.Extra \\else@>
@.Extra \\fi@>
    help1("I'm ignoring this; it doesn't match any \if.");
    error;
    end
else  begin while cur_chr<>fi_code do pass_text; {skip to \.{\\fi}}
  @<Pop the condition stack@>;
  end;
end

@* \[29] File names.
It's time now to fret about file names.  Besides the fact that different
operating systems treat files in different ways, we must cope with the
fact that completely different naming conventions are used by different
groups of people. The following programs show what is required for one
particular operating system; similar routines for other systems are not
difficult to devise.
@^fingers@>
@^system dependencies@>

\TeX\ assumes that a file name has three parts: the name proper; its
``extension''; and a ``file area'' where it is found in an external file
system.  The extension of an input file or a write file is assumed to be
`\.{.tex}' unless otherwise specified; it is `\.{.log}' on the
transcript file that records each run of \TeX; it is `\.{.tfm}' on the font
metric files that describe characters in the fonts \TeX\ uses; it is
`\.{.dvi}' on the output files that specify typesetting information; and it
is `\.{.fmt}' on the format files written by \.{INITEX} to initialize \TeX.
The file area can be arbitrary on input files, but files are usually
output to the user's current area.  If an input file cannot be
found on the specified area, \TeX\ will look for it on a special system
area; this special area is intended for commonly used input files like
\.{webmac.tex}.

Simple uses of \TeX\ refer only to file names that have no explicit
extension or area. For example, a person usually says `\.{\\input} \.{paper}'
or `\.{\\font\\tenrm} \.= \.{helvetica}' instead of `\.{\\input}
\.{paper.new}' or `\.{\\font\\tenrm} \.= \.{<csd.knuth>test}'. Simple file
names are best, because they make the \TeX\ source files portable;
whenever a file name consists entirely of letters and digits, it should be
treated in the same way by all implementations of \TeX. However, users
need the ability to refer to other files in their environment, especially
when responding to error messages concerning unopenable files; therefore
we want to let them use the syntax that appears in their favorite
operating system.

The following procedures don't allow spaces to be part of
file names; but some users seem to like names that are spaced-out.
System-dependent changes to allow such things should probably
be made with reluctance, and only when an entire file name that
includes spaces is ``quoted'' somehow.

@ Here are the global values that file names will be scanned into.

@<Glob...@>=
@!cur_name:str_number; {name of file just scanned}
@!cur_area:str_number; {file area just scanned, or \.{""}}
@!cur_ext:str_number; {file extension just scanned, or \.{""}}

@ The file names we shall deal with for illustrative purposes have the
following structure:  If the name contains `\.>' or `\.:', the file area
consists of all characters up to and including the final such character;
otherwise the file area is null.  If the remaining file name contains
`\..', the file extension consists of all such characters from the first
remaining `\..' to the end, otherwise the file extension is null.
@^system dependencies@>

We can scan such file names easily by using two global variables that keep track
of the occurrences of area and extension delimiters:

@<Glob...@>=
@!area_delimiter:pool_pointer; {the most recent `\.>' or `\.:', if any}
@!ext_delimiter:pool_pointer; {the relevant `\..', if any}

@ Input files that can't be found in the user's area may appear in a standard
system area called |TEX_area|. Font metric files whose areas are not given
explicitly are assumed to appear in a standard system area called
|TEX_font_area|.  $\Omega$'s compiled translation process files whose areas
are not given explicitly are assumed to appear in a standard system area
called |OMEGA_ocp_area|.  These system area names will, of course, vary
from place to place.
@^system dependencies@>

@d TEX_area=="TeXinputs:"
@.TeXinputs@>
@d TEX_font_area=="TeXfonts:"
@.TeXfonts@>
@d OMEGA_ocp_area=="OmegaOCPs:"
@.OmegaOCPs@>

@ Another system-dependent routine is needed to convert three internal
\TeX\ strings
into the |nameoffile| value that is used to open files. The present code
allows both lowercase and uppercase letters in the file name.
@^system dependencies@>

@d append_to_name(#)==begin c:=#; incr(k);
  if k<=file_name_size then nameoffile[k]:=xchr[c];
  end

@p procedure pack_file_name(@!n,@!a,@!e:str_number);
var k:integer; {number of positions filled in |nameoffile|}
@!c: ASCII_code; {character being packed}
@!j:pool_pointer; {index into |str_pool|}
begin k:=0;
for j:=str_start_macro(a) to str_start_macro(a+1)-1 do append_to_name(so(str_pool[j]));
for j:=str_start_macro(n) to str_start_macro(n+1)-1 do append_to_name(so(str_pool[j]));
for j:=str_start_macro(e) to str_start_macro(e+1)-1 do append_to_name(so(str_pool[j]));
if k<=file_name_size then namelength:=k@+else namelength:=file_name_size;
for k:=namelength+1 to file_name_size do nameoffile[k]:=' ';
end;

@ A messier routine is also needed, since format file names must be scanned
before \TeX's string mechanism has been initialized. We shall use the
global variable |TEX_format_default| to supply the text for default system areas
and extensions related to format files.
@^system dependencies@>

@d format_default_length=20 {length of the |TEX_format_default| string}
@d format_area_length=11 {length of its area part}
@d format_ext_length=4 {length of its `\.{.fmt}' part}
@d format_extension=='.fmt' {the extension, as a \.{WEB} constant}

@<Glob...@>=
@!TEX_format_default:packed array[1..format_default_length] of char;

@ @<Set init...@>=
TEX_format_default:='TeXformats:plain.fmt';
@.TeXformats@>
@.plain@>
@^system dependencies@>

@ @<Check the ``constant'' values for consistency@>=
if format_default_length>file_name_size then bad:=31;

@ Here is the messy routine that was just mentioned. It sets |nameoffile|
from the first |n| characters of |TEX_format_default|, followed by
|buffer[a..b]|, followed by the last |format_ext_length| characters of
|TEX_format_default|.

We dare not give error messages here, since \TeX\ calls this routine before
the |error| routine is ready to roll. Instead, we simply drop excess characters,
since the error will be detected in another way when a strange file name
isn't found.
@^system dependencies@>

@p procedure pack_buffered_name(@!n:integer;@!a,@!b:integer);
var k:integer; {number of positions filled in |nameoffile|}
@!c: ASCII_code; {character being packed}
@!j:integer; {index into |buffer| or |TEX_format_default|}
begin if n+b-a+1+format_ext_length>file_name_size then
  b:=a+file_name_size-n-1-format_ext_length;
k:=0;
for j:=1 to n do append_to_name(TEX_format_default[j]);
for j:=a to b do append_to_name(buffer[j]);
for j:=format_default_length-format_ext_length+1 to format_default_length do
  append_to_name(TEX_format_default[j]);
if k<=file_name_size then namelength:=k@+else namelength:=file_name_size;
for k:=namelength+1 to file_name_size do nameoffile[k]:=' ';
end;

@ Here is the only place we use |pack_buffered_name|. This part of the program
becomes active when a ``virgin'' \TeX\ is trying to get going, just after
the preliminary initialization, or when the user is substituting another
format file by typing `\.\&' after the initial `\.{**}' prompt.  The buffer
contains the first line of input in |buffer[loc..(last-1)]|, where
|loc<last| and |buffer[loc]<>" "|.

@<Declare the function called |open_fmt_file|@>=
function open_fmt_file:boolean;
label found,exit;
var j:0..buf_size; {the first space after the format file name}
begin j:=loc;
if buffer[loc]="&" then
  begin incr(loc); j:=loc; buffer[last]:=" ";
  while buffer[j]<>" " do incr(j);
  pack_buffered_name(0,loc,j-1); {try first without the system file area}
  if w_open_in(fmt_file) then goto found;
  pack_buffered_name(format_area_length,loc,j-1);
    {now try the system format file area}
  if w_open_in(fmt_file) then goto found;
  wake_up_terminal;
  wterm_ln('Sorry, I can''t find that format;',' will try PLAIN.');
@.Sorry, I can't find...@>
  update_terminal;
  end;
  {now pull out all the stops: try for the system \.{plain} file}
pack_buffered_name(format_default_length-format_ext_length,1,0);
if not w_open_in(fmt_file) then
  begin wake_up_terminal;
  wterm_ln('I can''t find the PLAIN format file!');
@.I can't find PLAIN...@>
@.plain@>
  open_fmt_file:=false; return;
  end;
found:loc:=j; open_fmt_file:=true;
exit:end;

@ Operating systems often make it possible to determine the exact name (and
possible version number) of a file that has been opened. The following routine,
which simply makes a \TeX\ string from the value of |nameoffile|, should
ideally be changed to deduce the full name of file~|f|, which is the file
most recently opened, if it is possible to do this in a \PASCAL\ program.
@^system dependencies@>

This routine might be called after string memory has overflowed, hence
we dare not use `|str_room|'.

@d a_make_name_string(#)==make_name_string
@d b_make_name_string(#)==make_name_string
@d w_make_name_string(#)==make_name_string


@ The global variable |name_in_progress| is used to prevent recursive
use of |scan_file_name|, since the |begin_name| and other procedures
communicate via global variables. Recursion would arise only by
devious tricks like `\.{\\input\\input f}'; such attempts at sabotage
must be thwarted. Furthermore, |name_in_progress| prevents \.{\\input}
@^recursion@>
from being initiated when a font size specification is being scanned.

Another global variable, |job_name|, contains the file name that was first
\.{\\input} by the user. This name is extended by `\.{.log}' and `\.{.dvi}'
and `\.{.fmt}' in the names of \TeX's output files.

@<Glob...@>=
@!name_in_progress:boolean; {is a file name being scanned?}
@!job_name:str_number; {principal file name}
@!log_opened:boolean; {has the transcript file been opened?}

@ Initially |job_name=0|; it becomes nonzero as soon as the true name is known.
We have |job_name=0| if and only if the `\.{log}' file has not been opened,
except of course for a short time just after |job_name| has become nonzero.

@d pack_cur_name==pack_file_name(cur_name,cur_area,cur_ext)

@<Initialize the output...@>=
job_name:=0; name_in_progress:=false; log_opened:=false;

@ Here's an example of how these conventions are used. Whenever it is time to
ship out a box of stuff, we shall use the macro |ensure_dvi_open|.

@d ensure_dvi_open==if output_file_name=0 then
  begin if job_name=0 then open_log_file;
  pack_job_name('.dvi');
  while not lua_b_open_out(dvi_file) do
    prompt_file_name('file name for output','.dvi');
  dvi_file:=name_file_pointer   ;
  output_file_name:=b_make_name_string(dvi_file);
  end

@<Glob...@>=
@!dvi_file: byte_file; {the device-independent output goes here}
@!output_file_name: str_number; {full name of the output file}
@!log_name:str_number; {full name of the log file}

@ @<Initialize the output...@>=output_file_name:=0;

@ The |open_log_file| routine is used to open the transcript file and to help
it catch up to what has previously been printed on the terminal.

@p procedure open_log_file;
var old_setting:0..max_selector; {previous |selector| setting}
@!k:0..buf_size; {index into |months| and |buffer|}
@!l:0..buf_size; {end of first input line}
@!months:packed array [1..36] of char; {abbreviations of month names}
begin old_setting:=selector;
if job_name=0 then job_name:="texput";
@.texput@>
pack_job_name('.log');
while not lua_a_open_out(addressof(log_file),0) do @<Try to get a different log file name@>;
log_file := name_file_pointer;
log_name:=a_make_name_string(log_file);
selector:=log_only; log_opened:=true;
if callback_defined(start_run_callback)=0 then begin
  @<Print the banner line, including the date and time@>;
  input_stack[input_ptr]:=cur_input; {make sure bottom level is in memory}
  print_nl("**");
@.**@>
  l:=input_stack[0].limit_field; {last position of first line}
  if buffer[l]=end_line_char then decr(l); { TODO: multichar endlinechar}
  for k:=1 to l do print(buffer[k]);
  print_ln; {now the transcript file contains the first line of input}
  end;
flush_loggable_info; {should be done always}
selector:=old_setting+2; {|log_only| or |term_and_log|}
end;

@ Sometimes |open_log_file| is called at awkward moments when \TeX\ is
unable to print error messages or even to |show_context|.
The |prompt_file_name| routine can result in a |fatal_error|, but the |error|
routine will not be invoked because |log_opened| will be false.

The normal idea of |batch_mode| is that nothing at all should be written
on the terminal. However, in the unusual case that
no log file could be opened, we make an exception and allow
an explanatory message to be seen.

Incidentally, the program always refers to the log file as a `\.{transcript
file}', because some systems cannot use the extension `\.{.log}' for
this file.

@<Try to get a different log file name@>=
begin selector:=term_only;
prompt_file_name('transcript file name','.log');
end

@ @<Print the banner...@>=
begin wlog(banner);
slow_print(format_ident); print("  ");
print_int(day); print_char(" ");
months:='JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC';
for k:=3*month-2 to 3*month do wlog(months[k]);
print_char(" "); print_int(year); print_char(" ");
print_two(time div 60); print_char(":"); print_two(time mod 60);
end

@ Let's turn now to the procedure that is used to initiate file reading
when an `\.{\\input}' command is being processed.

@p procedure start_input; {\TeX\ will \.{\\input} something}
label done;
var temp_str:str_number;
begin scan_file_name; {set |cur_name| to desired file name}
{|if cur_ext="" then cur_ext:=".tex";|}
pack_cur_name;
loop@+  begin begin_file_reading; {set up |cur_file| and new level of input}
  if lua_a_open_in(cur_file,0) then goto done;
  end_file_reading; {remove the level that didn't work}
  prompt_file_name('input file name','.tex');
  end;
done:
cur_file := name_file_pointer;
name:=a_make_name_string(cur_file);
if job_name=0 then
  begin job_name:=cur_name; open_log_file;
  end; {|open_log_file| doesn't |show_context|, so |limit|
    and |loc| needn't be set to meaningful values yet}
if tracefilenames then begin
  if term_offset+length(name)>max_print_line-2 then print_ln
  else if (term_offset>0)or(file_offset>0) then print_char(" ");
  print_char("(");
  slow_print(name);
end;
incr(open_parens);
update_terminal;
state:=new_line;
if name=str_ptr-1 then {we can conserve string pool space now}
  begin flush_string; name:=cur_name;
  end;
@<Prepare new file {\sl Sync\TeX} information@>;
@<Read the first line of the new file@>;
end;

@ Here we have to remember to tell the |lua_input_ln| routine not to
start with a |get|. If the file is empty, it is considered to
contain a single blank line.
@^system dependencies@>
@^empty line at end of file@>

@<Read the first line...@>=
begin line:=1;
if lua_input_ln(cur_file,0,false) then do_nothing;
firm_up_the_line;
if end_line_char_inactive then decr(limit)
else  buffer[limit]:=end_line_char;
first:=limit+1; loc:=start;
end

@* \[30] Font metric data and OCPS.
\TeX\ gets its knowledge about fonts from font metric files, also called
\.{TFM} files; the `\.T' in `\.{TFM}' stands for \TeX,
but other programs know about them too.
@:TFM files}{\.{TFM} files@>
@^font metric files@>

@ When the user defines \.{\\font\\f}, say, \TeX\ assigns an internal number
to the user's font~\.{\\f}. Adding this number to |font_id_base| gives the
|eqtb| location of a ``frozen'' control sequence that will always select
the font.

@<Types...@>=
@!internal_font_number=integer; {|font| in a |char_node|}
@!font_index=integer; {index into |font_info|}

@ @<Glob...@>=
@!font_bytes:integer;

@ \TeX\ always knows at least one font, namely the null font. It has no
characters, and its seven parameters are all equal to zero.

@<Initialize table...@>=
create_null_font;
font_bytes:=0;

@ @<Put each...@>=
primitive_tex("nullfont",set_font,null_font,0);
@!@:null_font_}{\.{\\nullfont} primitive@>
text(frozen_null_font):="nullfont"; eqtb[frozen_null_font]:=eqtb[cur_val];

@ @<The em width for |cur_font|@>=quad(cur_font)

@ @<The x-height for |cur_font|@>=x_height(cur_font)

@ Before we forget about the format of these tables, let's deal with two
of \TeX's basic scanning routines related to font information.

@<Declare procedures that scan font-related stuff@>=
procedure scan_font_ident;
var f:internal_font_number;
@!m:halfword;
begin @<Get the next non-blank non-call...@>;
if (cur_cmd=def_font) or (cur_cmd=letterspace_font) or (cur_cmd=pdf_copy_font) then f:=cur_font
else if cur_cmd=set_font then begin
  f:=cur_chr;
  set_font_touched(f,1);
  end
else if cur_cmd=def_family then begin
  m:=cur_chr; scan_math_family_int; f:=fam_fnt(cur_val,m);
  set_font_touched(f,1);
  end
else  begin print_err("Missing font identifier");
@.Missing font identifier@>
  help2("I was looking for a control sequence whose")@/
  ("current meaning has been defined by \font.");
  back_error; f:=null_font;
  end;
cur_val:=f;
end;

@ The following routine is used to implement `\.{\\fontdimen} |n| |f|'.
The boolean parameter |writing| is set |true| if the calling program
intends to change the parameter value.

@<Declare procedures that scan font-related stuff@>=
procedure set_font_dimen;forward;
procedure get_font_dimen;forward;

@ @p
procedure set_font_dimen;
label exit;
var f:internal_font_number;
@!n:integer; {the parameter number}
begin scan_int; n:=cur_val; scan_font_ident; f:=cur_val;
  if n<=0 then
    @<Issue a font parameter error message, and return@>
  else begin
    if n>font_params(f) then begin
      if font_touched(f) then @<Issue a font parameter error message, and return@>
      else @<Increase the number of parameters in the font@>;
      end;
    end;
  scan_optional_equals; scan_normal_dimen;
  set_font_param(f,n,cur_val);
exit:
end;
@#
procedure get_font_dimen;
label exit;
var f:internal_font_number;
@!n:integer; {the parameter number}
begin scan_int; n:=cur_val; scan_font_ident; f:=cur_val;
  cur_val:=0; { initialize return value }
  if n<=0 then
    @<Issue a font parameter error message, and return@>
  else begin
    if n>font_params(f) then begin
      if font_touched(f) then @<Issue a font parameter error message, and return@>
      else @<Increase the number of parameters in the font@>;
      end;
    end;
  cur_val:=font_param(f,n);
exit:
  scanned_result(cur_val)(dimen_val);
end;

@ @<Issue a font parameter error message, and return@>=
begin print_err("Font "); print_esc(font_id_text(f));
  print(" has only "); print_int(font_params(f));
  print(" fontdimen parameters");
@.Font x has only...@>
  help2("To increase the number of font parameters, you must")@/
    ("use \fontdimen immediately after the \font is loaded.");
  error;
  return;
end

@ @<Increase the number of parameters...@>=
begin repeat
  set_font_param(f,(font_params(f)+1),0);
until n=font_params(f);
end


@ When \TeX\ wants to typeset a character that doesn't exist, the
character node is not created; thus the output routine can assume
that characters exist when it sees them. The following procedure
prints a warning message unless the user has suppressed it.

@p procedure char_warning(@!f:internal_font_number;@!c:integer);
var old_setting: integer; {saved value of |tracing_online|}
    k:0..22; {index to current digit; we assume that $0\L n<16^{22}$}
begin if tracing_lost_chars>0 then
 begin old_setting:=tracing_online;
 if tracing_lost_chars>1 then tracing_online:=1;
  begin begin_diagnostic;
  print_nl("Missing character: There is no ");
@.Missing character@>
  print(c); print(" (U+");
  k:=0;
  if c<16 then print_char('0');
  if c<256 then print_char('0');
  if c<4096 then print_char('0');
  repeat dig[k]:=c mod 16; c:=c div 16; incr(k);
  until c=0;
  print_the_digs(k);
  print(") in font ");
  print_font_name(f);
  print_char("!"); end_diagnostic(false);
  end;
 tracing_online:=old_setting;
 end;
end;

@
@<Types...@>=
@!active_index=0..active_mem_size;

@
@d active_ocp(#)==active_info[#].hh.b0
@d active_counter(#)==active_info[#].hh.b1
@d active_lstack_no(#)==active_info[#+1].sc

@<Glob...@>=
@!active_info:array[active_index] of memory_word;
@!active_min_ptr:active_index; {first unused word of |active_info|}
@!active_max_ptr:active_index; {last unused word of |active_info|}
@!active_real:active_index;
@!holding:array[active_index] of ocp_list_index;

@
@<Initialize table...@>=
active_min_ptr:=0;
active_real:=0;

@
@p
function is_last_ocp(llstack_no:scaled; counter:integer):integer;
begin
active_min_ptr:=equiv(ocp_active_min_ptr_base);
active_max_ptr:=equiv(ocp_active_max_ptr_base);
active_real:=active_min_ptr;
while (active_real < active_max_ptr) and
      (active_lstack_no(active_real) < llstack_no) do begin
  active_real:=active_real+2;
  end;
while (active_real < active_max_ptr) and
      (active_lstack_no(active_real) = llstack_no) and
      (active_counter(active_real) <= counter) do begin
  active_real:=active_real+2;
  end;
is_last_ocp := (active_real=active_max_ptr);
end;

procedure print_active_ocps;
var i:integer;
begin
print_nl("Active ocps: [");
i:=active_min_ptr;
while i<active_max_ptr do begin
  print("(");
  print_scaled(active_lstack_no(i));
  print(",");
  print_int(active_counter(i));
  print(",");
  print_esc(ocp_id_text(active_ocp(i)));
  print(")");
  if i<>(active_max_ptr-2) then print(",");
  i:=i+2;
  end;
print("]");
end;

procedure add_ocp_stack(min_index:integer; min_value:scaled);
var p:ocp_lstack_index;
    llstack_no:scaled;
    counter:integer;
        m:scaled;
begin
m:=min_value; { TH: whatever this is ..}
p:=ocp_list_lstack(holding[min_index]);
llstack_no:=ocp_list_lstack_no(holding[min_index]);
counter:=0;
while not (is_null_ocp_lstack(p)) do begin
  active_ocp(active_max_ptr):=ocp_lstack_ocp(p);
  active_counter(active_max_ptr):=counter;
  active_lstack_no(active_max_ptr):=llstack_no;
  p:=ocp_lstack_lnext(p);
  active_max_ptr:=active_max_ptr+2;
  incr(counter);  {no overflow problem}
  end;
end;

procedure active_compile;
var i:integer;
    min_index:integer;
    min_stack_ocp:scaled;
    old_min:scaled;
    max_active:integer;
    stack_value:scaled;
begin
active_min_ptr:=active_max_ptr;
min_stack_ocp:=ocp_maxint;
max_active:=equiv(ocp_active_number_base)-1;
min_index:=max_active; {TH I hope ... }
for i:=max_active downto 0 do begin
  holding[i]:=ocp_list_list[equiv(ocp_active_base+i)];
  stack_value:=ocp_list_lstack_no(holding[i]);
  if stack_value<min_stack_ocp then begin
    min_index:=i;
    min_stack_ocp:=stack_value;
    end;
  end;
while min_stack_ocp<ocp_maxint do begin
  add_ocp_stack(min_index, min_stack_ocp);
  old_min:=min_stack_ocp;
  min_stack_ocp:=ocp_maxint;
  for i:=max_active downto 0 do begin
    stack_value:=ocp_list_lstack_no(holding[i]);
    while old_min=stack_value do begin
      holding[i]:=ocp_list_lnext(holding[i]);
      stack_value:=ocp_list_lstack_no(holding[i]);
      end;
    if stack_value<min_stack_ocp then begin
      min_index:=i;
      min_stack_ocp:=stack_value;
      end;
    end;
  end;
end;

@ Here we begin the \.{OCP} file handling.

@<Glob...@>=
@!ocp_file:byte_file;

@ So that is what \.{OCP} files hold.

When the user defines \.{\\ocp\\f}, say, \TeX\ assigns an internal number
to the user's ocp~\.{\\f}. Adding this number to |ocp_id_base| gives the
|eqtb| location of a ``frozen'' control sequence that will always select
the ocp.

@<Types...@>=
@!internal_ocp_number=ocp_base..ocp_biggest;
@!ocp_index=integer;

@ Here now is the array of ocp arrays.

@<Glob...@>=
@!ocp_ptr:internal_ocp_number; {largest internal ocp number in use}
@!ocp_buffer:^real_eight_bits; {byte buffer for ocp files}
@!ocp_size:integer; {total size of the ocp file}
@!ocp_cur:integer; {index into |ocp_buffer|}

@ @<Set init...@>=
ocp_buffer:=0; ocp_size:=0; ocp_cur:=0;

@ Besides the arrays just enumerated, we have two directory arrays that
make it easy to get at the individual entries in |ocp_info|.
The beginning of the info for the |j|-th state in the |i|-th ocp is at
location |ocp_info[ocp_state_base[i]+j]| and the |k|-th entry is in
location |ocp_info[ocp_info[ocp_state_base[i]+j]+k]|.
(These formulas assume that |min_quarterword| has already been
added to |i|, |j| and |k|, since $\Omega$ stores its quarterwords that way.)

@d ocp_info_end(#)==#]
@d ocp_info(#)==ocp_tables[#,ocp_info_end
@d offset_ocp_file_size=0
@d offset_ocp_name=1
@d offset_ocp_area=offset_ocp_name+1
@d offset_ocp_external=offset_ocp_area+1
@d offset_ocp_external_arg=offset_ocp_external+1
@d offset_ocp_input=offset_ocp_external_arg+1
@d offset_ocp_output=offset_ocp_input+1
@d offset_ocp_no_tables=offset_ocp_output+1
@d offset_ocp_no_states=offset_ocp_no_tables+1
@d offset_ocp_table_base=offset_ocp_no_states+1
@d offset_ocp_state_base=offset_ocp_table_base+1
@d offset_ocp_info=offset_ocp_state_base+1
@d ocp_file_size(#)==ocp_info(#)(offset_ocp_file_size)
@d ocp_name(#)==ocp_info(#)(offset_ocp_name)
@d ocp_area(#)==ocp_info(#)(offset_ocp_area)
@d ocp_external(#)==ocp_info(#)(offset_ocp_external)
@d ocp_external_arg(#)==ocp_info(#)(offset_ocp_external_arg)
@d ocp_input(#)==ocp_info(#)(offset_ocp_input)
@d ocp_output(#)==ocp_info(#)(offset_ocp_output)
@d ocp_no_tables(#)==ocp_info(#)(offset_ocp_no_tables)
@d ocp_no_states(#)==ocp_info(#)(offset_ocp_no_states)
@d ocp_table_base(#)==ocp_info(#)(offset_ocp_table_base)
@d ocp_state_base(#)==ocp_info(#)(offset_ocp_state_base)

@ $\Omega$ always knows at least one ocp, namely the null ocp.
It does nothing.

@<Initialize table...@>=
ocp_ptr:=null_ocp;
allocate_ocp_table(null_ocp,17);
ocp_file_size(null_ocp):=17;
ocp_name(null_ocp):="nullocp"; ocp_area(null_ocp):="";
ocp_external(null_ocp):=0; ocp_external_arg(null_ocp):=0;
ocp_input(null_ocp):=1; ocp_output(null_ocp):=1;
ocp_no_tables(null_ocp):=0;
ocp_no_states(null_ocp):=1;
ocp_table_base(f):=offset_ocp_info;
ocp_state_base(f):=offset_ocp_info;
ocp_info(null_ocp)(offset_ocp_info) := offset_ocp_info+2;  {number of entries}
ocp_info(null_ocp)(offset_ocp_info+1) := offset_ocp_info+5;  {number of entries}
ocp_info(null_ocp)(offset_ocp_info+2) := 23;  {|OTP_LEFT_START|}
ocp_info(null_ocp)(offset_ocp_info+3) := 3;  {|OTP_RIGHT_CHAR|}
ocp_info(null_ocp)(offset_ocp_info+4) := 36;  {|OTP_STOP|}


@ @<Put each...@>=
primitive_omega("nullocp", set_ocp, null_ocp,0);
text(frozen_null_ocp) := "nullocp";
eqtb[frozen_null_ocp] := eqtb[cur_val];
geq_define(ocp_active_number_base, data, 0);
geq_define(ocp_active_min_ptr_base, data, 0);
geq_define(ocp_active_max_ptr_base, data, 0);

@ Of course we want to define macros that suppress the detail of how ocp
information is actually packed, so that we don't have to write things like
$$\hbox{|ocp_info[k+ocp_info[j+ocp_state_base[i]]]|}$$
too often. The \.{WEB} definitions here make |ocp_state_entry(i)(j)(k)|
(|ocp_table_entry(i)(j)(k)|) the |k|-th word in the |j|-th state (table)
of the |i|-th ocp.
@^inner loop@>

@d ocp_state_end(#)==#]
@d ocp_state_one(#)==#*2]+ocp_state_end
@d ocp_state_entry(#)==ocp_tables[#,ocp_tables[#,ocp_state_base(#)+ocp_state_one

@d ocp_state_no_end(#)==#*2+1]
@d ocp_state_no(#)==ocp_tables[#,ocp_state_base(#)+ocp_state_no_end

@d ocp_table_end(#)==#]
@d ocp_table_one(#)==#*2]+ocp_table_end
@d ocp_table_entry(#)==ocp_tables[#,ocp_tables[#,ocp_table_base(#)+ocp_table_one

@d ocp_table_no_end(#)==#*2+1]
@d ocp_table_no(#)==ocp_tables[#,ocp_table_base(#)+ocp_table_no_end

@ $\Omega$ checks the information of a \.{OCP} file for validity as the
file is being read in, so that no further checks will be needed when
typesetting is going on. The somewhat tedious subroutine that does this
is called |read_ocp_info|. It has three parameters: the user ocp
identifier~|u|, and the file name and area strings |nom| and |aire|.

The subroutine opens and closes a global file variable called |ocp_file|.
It returns the value of the internal ocp number that was just loaded.
If an error is detected, an error message is issued and no ocp
information is stored; |null_ocp| is returned in this case.

@d bad_ocp=11 {label for |read_ocp_info|}
@d ocp_abort(#)==begin print("OCP file error (");
 print(#); print(")"); print_ln; goto bad_ocp end
 {do this when the \.{OCP} data is wrong}

@p function read_ocp_info(@!u:pointer;@!nom,@!aire,@!ext:str_number;
                          @!external_ocp:boolean)
  :internal_ocp_number; {input a \.{OCP} file}
label done,bad_ocp,not_found;
var
@!file_opened:boolean; {was |ocp_file| successfully opened?}
@!k:integer;
@!res:boolean;
@!callback_id:integer;
@!fnam:str_number;
@!f:internal_ocp_number; {the new ocp's number}
@!g:internal_ocp_number; {the number to return}
@!ocpword:integer;
@!ocpmem_run_ptr:ocp_index;
@!ocp_length,real_ocp_length:integer; {length of ocp file}
@!previous_address:ocp_index;
@!temp_ocp_input:integer;
@!temp_ocp_output:integer;
@!temp_ocp_no_tables:integer;
@!temp_ocp_no_states:integer;
@!i,new_offset,room_for_tables,room_for_states:integer;
begin g:=null_ocp; f:=null_ocp;@/
@<Read and check the ocp data; |ocp_abort| if the \.{OCP} file is
  malformed; if there's no room for this ocp, say so and |goto
  done|; otherwise |incr(ocp_ptr)| and |goto done|@>;
bad_ocp: @<Report that the ocp won't be loaded@>;
done:
ocp_name(f):=nom; ocp_area(f):=aire;
read_ocp_info:=g;
end;

@ $\Omega$ does not give precise details about why it
rejects a particular \.{OCP} file.

@d start_ocp_error_message==print_err("Translation process ");
   sprint_cs(u); print_char("="); print_file_name(nom,aire,"");

@<Report that the ocp won't be loaded@>=
start_ocp_error_message;
@.Translation process x=xx not loadable...@>
if file_opened then print(" not loadable: Bad ocp file")
else print(" not loadable: ocp file not found");
help2("I wasn't able to read the data for this ocp,")@/
("so I will ignore the ocp specification.");
error

@ @<Read and check the ocp data...@>=
if external_ocp then
  @<Check |ocp_file| exists@>
else begin
  @<Open |ocp_file| for input@>;
  @<Read the {\.{OCP}} file@>;
  end;

@ @<Check |ocp_file| exists@>=
begin
file_opened:=false;
pack_file_name(nom,aire,ext);
b_test_in;
if namelength=0 then ocp_abort("opening file");
f :=ocp_ptr+1;
allocate_ocp_table(f,13);
ocp_file_size(f):=13;
for i:=1 to namelength do begin
  append_char(nameoffile[i]);
  end;
ocp_external(f):=make_string;
scan_string_argument;
ocp_external_arg(f):=cur_val;
ocp_name(f):=""; ocp_area(f):="";
ocp_state_base(f):=0; ocp_table_base(f):=0;
ocp_input(f):=1; ocp_output(f):=1;
ocp_info(f)(offset_ocp_info):=0;
ocp_ptr:=f; g:=f;
goto done;
end

@ @<Open |ocp_file| for input@>=
file_opened:=false;
pack_file_name(nom,aire,".ocp");
if ocp_buffer<>0 then libcfree(ocp_buffer);
ocp_cur:=0; ocp_buffer:=0; ocp_size:=0;
callback_id:=callback_defined(find_ocp_file_callback);
if callback_id>0 then begin
  res := run_callback(callback_id,'S->s',stringcast(nameoffile+1), addressof(fnam));
  if (res)and(fnam<>0)and(length(fnam)>0) then begin
    @<Fixup |nameoffile| after callback@>;
    end;
  end;
callback_id:=callback_defined(read_ocp_file_callback);
if callback_id>0 then begin
  res := run_callback(callback_id,'S->bSd',stringcast(nameoffile+1),
          addressof(file_opened), addressof(ocp_buffer),addressof(ocp_size));
  if not res         then ocp_abort("callback error");
  if not file_opened then ocp_abort("opening file");
  if not ocp_size    then ocp_abort("checking size");
  end
else begin
  if not ocp_open_in(ocp_file) then ocp_abort("opening file");
  file_opened:=true;
  res := read_ocp_file(ocp_file,addressof(ocp_buffer),addressof(ocp_size));
  b_close(ocp_file);
  if not ocp_size then ocp_abort("checking size");
  if not res      then ocp_abort("reading file");
end


@ Note: A malformed \.{OCP} file might be shorter than it claims to be;
thus |eof(ocp_file)| might be true when |read_ocp_info| refers to
|ocp_file^| or when it says |get(ocp_file)|. If such circumstances
cause system error messages, you will have to defeat them somehow,
for example by defining |ocpget| to be `\ignorespaces|begin get(ocp_file);|
|if eof(ocp_file) then ocp_abort; end|\unskip'.
@^system dependencies@>

@d add_to_ocp_info(#)==begin ocp_tables[f,ocpmem_run_ptr]:=#;
  incr(ocpmem_run_ptr);
  end
@d ocpget==incr(ocp_cur)
@d ocpbyte==ocp_buffer[ocp_cur]
@d ocp_read(#)==begin ocpword:=ocpbyte;
  if ocpword>127 then ocp_abort("checking first octet");
  ocpget; ocpword:=ocpword*@'400+ocpbyte;
  ocpget; ocpword:=ocpword*@'400+ocpbyte;
  ocpget; ocpword:=ocpword*@'400+ocpbyte;
  #:=ocpword;
  end
@d ocp_read_all(#)==begin ocpget; ocp_read(#); end
@d ocp_read_info==begin ocp_read_all(ocpword);
  add_to_ocp_info(ocpword);
  end

@ @<Read the {\.{OCP}} file@>=
begin
f :=ocp_ptr+1;
ocpmem_run_ptr:=offset_ocp_info;
ocp_read(ocp_length);
real_ocp_length:=ocp_length-7;
ocp_read_all(temp_ocp_input);
ocp_read_all(temp_ocp_output);
ocp_read_all(temp_ocp_no_tables);
ocp_read_all(room_for_tables);
ocp_read_all(temp_ocp_no_states);
ocp_read_all(room_for_states);
if real_ocp_length <>
   (temp_ocp_no_tables + room_for_tables +
    temp_ocp_no_states + room_for_states) then
  ocp_abort("checking size");
real_ocp_length:=real_ocp_length+12+
   temp_ocp_no_states+temp_ocp_no_tables;
allocate_ocp_table(f,real_ocp_length);
ocp_external(f):=0;
ocp_external_arg(f):=0;
ocp_file_size(f):=real_ocp_length;
ocp_input(f):=temp_ocp_input;
ocp_output(f):=temp_ocp_output;
ocp_no_tables(f):=temp_ocp_no_tables;
ocp_no_states(f):=temp_ocp_no_states;
ocp_table_base(f):=ocpmem_run_ptr;
if ocp_no_tables(f) <> 0 then begin
  previous_address:=ocpmem_run_ptr+2*(ocp_no_tables(f));
  for i:=1 to ocp_no_tables(f) do begin
    add_to_ocp_info(previous_address);
    ocp_read_all(new_offset);
    add_to_ocp_info(new_offset);
    previous_address:=previous_address+new_offset;
    end
  end;
if room_for_tables <> 0 then begin
  for i:=1 to room_for_tables do begin
    ocp_read_info;
    end
  end;
ocp_state_base(f):=ocpmem_run_ptr;
if ocp_no_states(f) <> 0 then begin
  previous_address:=ocpmem_run_ptr+2*(ocp_no_states(f));
  for i:=1 to ocp_no_states(f) do begin
    add_to_ocp_info(previous_address);
    ocp_read_all(new_offset);
    add_to_ocp_info(new_offset);
    previous_address:=previous_address+new_offset;
    end;
  end;
if room_for_states <> 0 then begin
  for i:=1 to room_for_states do begin
    ocp_read_info;
    end
  end;
ocp_ptr:=f; g:=f;
goto done;
end

@ Before we forget about the format of these tables, let's deal with
$\Omega$'s basic scanning routine related to ocp information.

@<Declare procedures that scan ocp-related stuff@>=
procedure scan_ocp_ident;
var f:internal_ocp_number;
begin @<Get the next non-blank non-call...@>;
if cur_cmd=set_ocp then f:=cur_chr
else  begin print_err("Missing ocp identifier");
@.Missing ocp identifier@>
  help2("I was looking for a control sequence whose")@/
  ("current meaning has been defined by \ocp.");
  back_error; f:=null_ocp;
  end;
cur_val:=f;
end;


@ Here we begin the \.{OCP} list handling.


@<Types...@>=
@!internal_ocp_list_number=ocp_list_base..ocp_list_biggest;
@!ocp_list_index=integer; {index into |ocp_list_info|}
@!ocp_lstack_index=integer; {index into |ocp_lstack_info|}

@ Here now is the array of ocp arrays.
@d ocp_list_lnext(#)==ocp_list_info[#].hh.b0
@d ocp_list_lstack(#)==ocp_list_info[#].hh.b1
@d ocp_list_lstack_no(#)==ocp_list_info[#+1].sc
@d ocp_lstack_lnext(#)==ocp_lstack_info[#].hh.b0
@d ocp_lstack_ocp(#)==ocp_lstack_info[#].hh.b1
@d make_null_ocp_list==make_ocp_list_node(0,ocp_maxint,0)
@d is_null_ocp_list(#)==ocp_list_lstack_no(#)=ocp_maxint
@d make_null_ocp_lstack==0
@d is_null_ocp_lstack(#)==#=0
@d add_before_op=1
@d add_after_op=2
@d remove_before_op=3
@d remove_after_op=4

@<Glob...@>=
@!ocp_list_info:array[ocp_list_index] of memory_word;
  {the big collection of ocp list data}
@!ocp_listmem_ptr:ocp_list_index; {first unused word of |ocp_list_info|}
@!ocp_listmem_run_ptr:ocp_list_index; {temp unused word of |ocp_list_info|}
@!ocp_lstack_info:array[ocp_lstack_index] of memory_word;
  {the big collection of ocp lstack data}
@!ocp_lstackmem_ptr:ocp_lstack_index; {first unused word of |ocp_lstack_info|}
@!ocp_lstackmem_run_ptr:ocp_lstack_index; {temp unused word of |ocp_lstack_info|}
@!ocp_list_ptr:internal_ocp_list_number; {largest internal ocp list number in use}
@!ocp_list_list:array[internal_ocp_list_number] of ocp_list_index;

@
@<Initialize table...@>=
ocp_listmem_ptr:=2;
ocp_list_lstack(0):=0;
ocp_list_lstack_no(0):=ocp_maxint;
ocp_list_lnext(0):=0;
ocp_list_ptr:=null_ocp_list;
ocp_list_list[null_ocp_list]:=0;
ocp_lstackmem_ptr:=1;

@ $\Omega$ always knows at least one ocp list, namely the null ocp list.

@ @<Put each...@>=
primitive_omega("nullocplist", set_ocp_list, null_ocp_list,0);
text(frozen_null_ocp_list) := "nullocplist";
eqtb[frozen_null_ocp_list] := eqtb[cur_val];

@ @p function make_ocp_list_node(llstack:ocp_lstack_index;
                                 llstack_no:scaled;
                                 llnext:ocp_list_index):ocp_list_index;
var p:ocp_list_index;
begin
p:=ocp_listmem_run_ptr;
ocp_list_lstack(p):=llstack;
ocp_list_lstack_no(p):=llstack_no;
ocp_list_lnext(p):=llnext;
ocp_listmem_run_ptr:=ocp_listmem_run_ptr+2;
if ocp_listmem_run_ptr>=ocp_list_size then
  overflow("ocp_list_size",ocp_list_size);
make_ocp_list_node:=p;
end;

function make_ocp_lstack_node(locp:internal_ocp_number;
                              llnext:ocp_lstack_index) : ocp_lstack_index;
var p:ocp_lstack_index;
begin
p:=ocp_lstackmem_run_ptr;
ocp_lstack_ocp(p):=locp;
ocp_lstack_lnext(p):=llnext;
incr(ocp_lstackmem_run_ptr);
if ocp_lstackmem_run_ptr>=ocp_stack_size then
  overflow("ocp_stack_size",ocp_stack_size);
make_ocp_lstack_node:=p;
end;

function copy_ocp_lstack(llstack:ocp_lstack_index):ocp_lstack_index;
var result:ocp_lstack_index;
begin
if is_null_ocp_lstack(llstack) then
  result:=make_null_ocp_lstack
else
  result:=make_ocp_lstack_node(ocp_lstack_ocp(llstack),
                               copy_ocp_lstack(ocp_lstack_lnext(llstack)));
copy_ocp_lstack:=result;
end;

function copy_ocp_list(list:ocp_list_index):ocp_list_index;
var result:ocp_list_index;
begin
if is_null_ocp_list(list) then
  result:=make_null_ocp_list
else
  result:=make_ocp_list_node(copy_ocp_lstack(ocp_list_lstack(list)),
                             ocp_list_lstack_no(list),
                             copy_ocp_list(ocp_list_lnext(list)));
copy_ocp_list:=result;
end;

function ocp_ensure_lstack(list:ocp_list_index; llstack_no:scaled):
   ocp_list_index;
var p:ocp_list_index;
    q:ocp_list_index;
begin
p:=list;
if is_null_ocp_list(p) then begin
  ocp_list_lstack_no(p) := llstack_no;
  ocp_list_lnext(p) := make_null_ocp_list;
  end
else if ocp_list_lstack_no(p) > llstack_no then begin
  ocp_list_lnext(p):=
    make_ocp_list_node(ocp_list_lstack(p),
                       ocp_list_lstack_no(p),
                       ocp_list_lnext(p));
  ocp_list_lstack(p):=0;
  ocp_list_lstack_no(p):=llstack_no;
  end
else begin
  q:=ocp_list_lnext(p);
  while (not (is_null_ocp_list(q))) and
         ocp_list_lstack_no(q) <= llstack_no do begin
    p:=q; q:=ocp_list_lnext(q);
    end;
  if ocp_list_lstack_no(p) < llstack_no then begin
    ocp_list_lnext(p) := make_ocp_list_node(0, llstack_no, q);
    p := ocp_list_lnext(p);
    end;
  end;
ocp_ensure_lstack := p;
end;

procedure ocp_apply_add(list_entry:ocp_list_index;
                        lbefore:boolean;
                        locp:internal_ocp_number);
var p:ocp_lstack_index;
    q:ocp_lstack_index;
begin
p := ocp_list_lstack(list_entry);
if lbefore or (p=0) then begin
  ocp_list_lstack(list_entry) := make_ocp_lstack_node(locp, p);
  end
else begin
  q:=ocp_lstack_lnext(p);
  while q<>0 do begin
    p:=q; q:=ocp_lstack_lnext(q);
    end;
  ocp_lstack_lnext(p):=make_ocp_lstack_node(locp,0);
  end;
end;

procedure ocp_apply_remove(list_entry:ocp_list_index;
                           lbefore:boolean);
var p:ocp_lstack_index;
    q:ocp_lstack_index;
    r:ocp_lstack_index;
begin
p := ocp_list_lstack(list_entry);
if p=0 then begin
  print_err("warning: stack entry already empty"); print_ln
  end
else begin
  q := ocp_lstack_lnext(p);
  if lbefore or (q=0) then
    ocp_list_lstack(list_entry) := q
  else begin
    r:=ocp_lstack_lnext(q);
    while r <> 0 do begin
      p:=q; q:=r; r:=ocp_lstack_lnext(r);
      end;
    ocp_lstack_lnext(p) := 0;
    end
  end;
end;

procedure scan_scaled; {sets |cur_val| to a scaled value}
label done, done1, done2, found, not_found, attach_fraction;
var negative:boolean; {should the answer be negated?}
@!f:integer; {numerator of a fraction whose denominator is $2^{16}$}
@!k,@!kk:small_number; {number of digits in a decimal fraction}
@!p,@!q:pointer; {top of decimal digit stack}
begin f:=0; arith_error:=false; negative:=false;
@<Get the next non-blank non-sign...@>;
back_input;
if cur_tok=continental_point_token then cur_tok:=point_token;
if cur_tok<>point_token then scan_int
else  begin radix:=10; cur_val:=0;
  end;
if cur_tok=continental_point_token then cur_tok:=point_token;
if (radix=10)and(cur_tok=point_token) then @<Scan decimal fraction@>;
if cur_val<0 then {in this case |f=0|}
  begin negative := not negative; negate(cur_val);
  end;
if cur_val>@'40000 then arith_error:=true
else cur_val := cur_val*unity +f;
if arith_error or(abs(cur_val)>=@'10000000000) then
begin print_err("Stack number too large"); error;
end;
if negative then negate(cur_val);
end;

procedure print_ocp_lstack(lstack_entry:ocp_lstack_index);
var p:ocp_lstack_index;
begin
p:=lstack_entry;
while (p<>0) do begin
  print_esc(ocp_id_text(ocp_lstack_ocp(p)));
  p:=ocp_lstack_lnext(p);
  if (p<>0) then print(",");
  end;
end;

procedure print_ocp_list(list_entry:ocp_list_index);
var p:ocp_list_index;
begin
print("["); p:=list_entry;
while not (is_null_ocp_list(p)) do begin
  print("(");
  print_scaled(ocp_list_lstack_no(p));
  print(" : ");
  print_ocp_lstack(ocp_list_lstack(p));
  print(")");
  p:=ocp_list_lnext(p);
  if not (is_null_ocp_list(p)) then print(", ");
  end;
print("]");
end;

function scan_ocp_list: ocp_list_index;
var llstack_no:scaled;
    lop:quarterword;
    lstack_entry:ocp_list_index;
    other_list:ocp_list_index;
    ocp_ident:internal_ocp_number;
    result:ocp_list_index;
begin
get_r_token;
if cur_cmd = set_ocp_list then
  result := copy_ocp_list(ocp_list_list[cur_chr])
else if cur_cmd <> ocp_list_op then begin
  print_err("Bad ocp list specification");
@.Bad ocp list specification@>
  help1("I was looking for a ocp list specification.");
  error;
  result := make_null_ocp_list;
  end
else begin
  lop:=cur_chr;
  scan_scaled; llstack_no:=cur_val;
  if (llstack_no<=0) or (llstack_no>=ocp_maxint) then begin
    print_err("Stack numbers must be between 0 and 4096 (exclusive)");
    error;
    result := make_null_ocp_list;
    end
  else begin
    if lop <= add_after_op then begin
      scan_ocp_ident; ocp_ident:=cur_val;
      end;
    other_list:=scan_ocp_list;
    lstack_entry:=ocp_ensure_lstack(other_list, llstack_no);
    if lop <= add_after_op then
      ocp_apply_add(lstack_entry, (lop=add_before_op), ocp_ident)
    else
      ocp_apply_remove(lstack_entry, (lop=remove_before_op));
    result:=other_list;
    end;
  end;
scan_ocp_list:=result;
end;

function read_ocp_list: internal_ocp_list_number;
var f:internal_ocp_list_number;
    g:internal_ocp_list_number;
begin
g:=null_ocp_list;
f:=ocp_list_ptr+1;
ocp_listmem_run_ptr:=ocp_listmem_ptr;
ocp_lstackmem_run_ptr:=ocp_lstackmem_ptr;
ocp_list_list[f]:=scan_ocp_list;
ocp_list_ptr:=f;
ocp_listmem_ptr:=ocp_listmem_run_ptr;
ocp_lstackmem_ptr:=ocp_lstackmem_run_ptr;
g:=f;
read_ocp_list:=g;
end;

procedure scan_ocp_list_ident;
var f:internal_ocp_list_number;
begin @<Get the next non-blank non-call...@>;
if cur_cmd=set_ocp_list then f:=cur_chr
else  begin print_err("Missing ocp list identifier");
@.Missing ocp list identifier@>
  help2("I was looking for a control sequence whose")@/
  ("current meaning has been defined by \ocplist.");
  back_error; f:=null_ocp_list;
  end;
cur_val:=f;
end;


@* \[31] Device-independent file format.
The most important output produced by a run of \TeX\ is the ``device
independent'' (\.{DVI}) file that specifies where characters and rules
are to appear on printed pages. The form of these files was designed by
David R. Fuchs in 1979. Almost any reasonable typesetting device can be
@^Fuchs, David Raymond@>
@:DVI_files}{\.{DVI} files@>
driven by a program that takes \.{DVI} files as input, and dozens of such
\.{DVI}-to-whatever programs have been written. Thus, it is possible to
print the output of \TeX\ on many different kinds of equipment, using \TeX\
as a device-independent ``front end.''

A \.{DVI} file is a stream of 8-bit bytes, which may be regarded as a
series of commands in a machine-like language. The first byte of each command
is the operation code, and this code is followed by zero or more bytes
that provide parameters to the command. The parameters themselves may consist
of several consecutive bytes; for example, the `|set_rule|' command has two
parameters, each of which is four bytes long. Parameters are usually
regarded as nonnegative integers; but four-byte-long parameters,
and shorter parameters that denote distances, can be
either positive or negative. Such parameters are given in two's complement
notation. For example, a two-byte-long distance parameter has a value between
$-2^{15}$ and $2^{15}-1$. As in \.{TFM} files, numbers that occupy
more than one byte position appear in BigEndian order.

A \.{DVI} file consists of a ``preamble,'' followed by a sequence of one
or more ``pages,'' followed by a ``postamble.'' The preamble is simply a
|pre| command, with its parameters that define the dimensions used in the
file; this must come first.  Each ``page'' consists of a |bop| command,
followed by any number of other commands that tell where characters are to
be placed on a physical page, followed by an |eop| command. The pages
appear in the order that \TeX\ generated them. If we ignore |nop| commands
and \\{fnt\_def} commands (which are allowed between any two commands in
the file), each |eop| command is immediately followed by a |bop| command,
or by a |post| command; in the latter case, there are no more pages in the
file, and the remaining bytes form the postamble.  Further details about
the postamble will be explained later.

Some parameters in \.{DVI} commands are ``pointers.'' These are four-byte
quantities that give the location number of some other byte in the file;
the first byte is number~0, then comes number~1, and so on. For example,
one of the parameters of a |bop| command points to the previous |bop|;
this makes it feasible to read the pages in backwards order, in case the
results are being directed to a device that stacks its output face up.
Suppose the preamble of a \.{DVI} file occupies bytes 0 to 99. Now if the
first page occupies bytes 100 to 999, say, and if the second
page occupies bytes 1000 to 1999, then the |bop| that starts in byte 1000
points to 100 and the |bop| that starts in byte 2000 points to 1000. (The
very first |bop|, i.e., the one starting in byte 100, has a pointer of~$-1$.)

@ The \.{DVI} format is intended to be both compact and easily interpreted
by a machine. Compactness is achieved by making most of the information
implicit instead of explicit. When a \.{DVI}-reading program reads the
commands for a page, it keeps track of several quantities: (a)~The current
font |f| is an integer; this value is changed only
by \\{fnt} and \\{fnt\_num} commands. (b)~The current position on the page
is given by two numbers called the horizontal and vertical coordinates,
|h| and |v|. Both coordinates are zero at the upper left corner of the page;
moving to the right corresponds to increasing the horizontal coordinate, and
moving down corresponds to increasing the vertical coordinate. Thus, the
coordinates are essentially Cartesian, except that vertical directions are
flipped; the Cartesian version of |(h,v)| would be |(h,-v)|.  (c)~The
current spacing amounts are given by four numbers |w|, |x|, |y|, and |z|,
where |w| and~|x| are used for horizontal spacing and where |y| and~|z|
are used for vertical spacing. (d)~There is a stack containing
|(h,v,w,x,y,z)| values; the \.{DVI} commands |push| and |pop| are used to
change the current level of operation. Note that the current font~|f| is
not pushed and popped; the stack contains only information about
positioning.

The values of |h|, |v|, |w|, |x|, |y|, and |z| are signed integers having up
to 32 bits, including the sign. Since they represent physical distances,
there is a small unit of measurement such that increasing |h| by~1 means
moving a certain tiny distance to the right. The actual unit of
measurement is variable, as explained below; \TeX\ sets things up so that
its \.{DVI} output is in sp units, i.e., scaled points, in agreement with
all the |scaled| dimensions in \TeX's data structures.

@ Here is a list of all the commands that may appear in a \.{DVI} file. Each
command is specified by its symbolic name (e.g., |bop|), its opcode byte
(e.g., 139), and its parameters (if any). The parameters are followed
by a bracketed number telling how many bytes they occupy; for example,
`|p[4]|' means that parameter |p| is four bytes long.

\yskip\hang|set_char_0| 0. Typeset character number~0 from font~|f|
such that the reference point of the character is at |(h,v)|. Then
increase |h| by the width of that character. Note that a character may
have zero or negative width, so one cannot be sure that |h| will advance
after this command; but |h| usually does increase.

\yskip\hang\\{set\_char\_1} through \\{set\_char\_127} (opcodes 1 to 127).
Do the operations of |set_char_0|; but use the character whose number
matches the opcode, instead of character~0.

\yskip\hang|set1| 128 |c[1]|. Same as |set_char_0|, except that character
number~|c| is typeset. \TeX82 uses this command for characters in the
range |128<=c<256|.

\yskip\hang|@!set2| 129 |c[2]|. Same as |set1|, except that |c|~is two
bytes long, so it is in the range |0<=c<65536|. \TeX82 never uses this
command, but it should come in handy for extensions of \TeX\ that deal
with oriental languages.
@^oriental characters@>@^Chinese characters@>@^Japanese characters@>

\yskip\hang|@!set3| 130 |c[3]|. Same as |set1|, except that |c|~is three
bytes long, so it can be as large as $2^{24}-1$. Not even the Chinese
language has this many characters, but this command might prove useful
in some yet unforeseen extension.

\yskip\hang|@!set4| 131 |c[4]|. Same as |set1|, except that |c|~is four
bytes long. Imagine that.

\yskip\hang|set_rule| 132 |a[4]| |b[4]|. Typeset a solid black rectangle
of height~|a| and width~|b|, with its bottom left corner at |(h,v)|. Then
set |h:=h+b|. If either |a<=0| or |b<=0|, nothing should be typeset. Note
that if |b<0|, the value of |h| will decrease even though nothing else happens.
See below for details about how to typeset rules so that consistency with
\MF\ is guaranteed.

\yskip\hang|@!put1| 133 |c[1]|. Typeset character number~|c| from font~|f|
such that the reference point of the character is at |(h,v)|. (The `put'
commands are exactly like the `set' commands, except that they simply put out a
character or a rule without moving the reference point afterwards.)

\yskip\hang|@!put2| 134 |c[2]|. Same as |set2|, except that |h| is not changed.

\yskip\hang|@!put3| 135 |c[3]|. Same as |set3|, except that |h| is not changed.

\yskip\hang|@!put4| 136 |c[4]|. Same as |set4|, except that |h| is not changed.

\yskip\hang|put_rule| 137 |a[4]| |b[4]|. Same as |set_rule|, except that
|h| is not changed.

\yskip\hang|nop| 138. No operation, do nothing. Any number of |nop|'s
may occur between \.{DVI} commands, but a |nop| cannot be inserted between
a command and its parameters or between two parameters.

\yskip\hang|bop| 139 $c_0[4]$ $c_1[4]$ $\ldots$ $c_9[4]$ $p[4]$. Beginning
of a page: Set |(h,v,w,x,y,z):=(0,0,0,0,0,0)| and set the stack empty. Set
the current font |f| to an undefined value.  The ten $c_i$ parameters hold
the values of \.{\\count0} $\ldots$ \.{\\count9} in \TeX\ at the time
\.{\\shipout} was invoked for this page; they can be used to identify
pages, if a user wants to print only part of a \.{DVI} file. The parameter
|p| points to the previous |bop| in the file; the first
|bop| has $p=-1$.

\yskip\hang|eop| 140.  End of page: Print what you have read since the
previous |bop|. At this point the stack should be empty. (The \.{DVI}-reading
programs that drive most output devices will have kept a buffer of the
material that appears on the page that has just ended. This material is
largely, but not entirely, in order by |v| coordinate and (for fixed |v|) by
|h|~coordinate; so it usually needs to be sorted into some order that is
appropriate for the device in question.)

\yskip\hang|push| 141. Push the current values of |(h,v,w,x,y,z)| onto the
top of the stack; do not change any of these values. Note that |f| is
not pushed.

\yskip\hang|pop| 142. Pop the top six values off of the stack and assign
them respectively to |(h,v,w,x,y,z)|. The number of pops should never
exceed the number of pushes, since it would be highly embarrassing if the
stack were empty at the time of a |pop| command.

\yskip\hang|right1| 143 |b[1]|. Set |h:=h+b|, i.e., move right |b| units.
The parameter is a signed number in two's complement notation, |-128<=b<128|;
if |b<0|, the reference point moves left.

\yskip\hang|right2| 144 |b[2]|. Same as |right1|, except that |b| is a
two-byte quantity in the range |-32768<=b<32768|.

\yskip\hang|right3| 145 |b[3]|. Same as |right1|, except that |b| is a
three-byte quantity in the range |@t$-2^{23}$@><=b<@t$2^{23}$@>|.

\yskip\hang|right4| 146 |b[4]|. Same as |right1|, except that |b| is a
four-byte quantity in the range |@t$-2^{31}$@><=b<@t$2^{31}$@>|.

\yskip\hang|w0| 147. Set |h:=h+w|; i.e., move right |w| units. With luck,
this parameterless command will usually suffice, because the same kind of motion
will occur several times in succession; the following commands explain how
|w| gets particular values.

\yskip\hang|w1| 148 |b[1]|. Set |w:=b| and |h:=h+b|. The value of |b| is a
signed quantity in two's complement notation, |-128<=b<128|. This command
changes the current |w|~spacing and moves right by |b|.

\yskip\hang|@!w2| 149 |b[2]|. Same as |w1|, but |b| is two bytes long,
|-32768<=b<32768|.

\yskip\hang|@!w3| 150 |b[3]|. Same as |w1|, but |b| is three bytes long,
|@t$-2^{23}$@><=b<@t$2^{23}$@>|.

\yskip\hang|@!w4| 151 |b[4]|. Same as |w1|, but |b| is four bytes long,
|@t$-2^{31}$@><=b<@t$2^{31}$@>|.

\yskip\hang|x0| 152. Set |h:=h+x|; i.e., move right |x| units. The `|x|'
commands are like the `|w|' commands except that they involve |x| instead
of |w|.

\yskip\hang|x1| 153 |b[1]|. Set |x:=b| and |h:=h+b|. The value of |b| is a
signed quantity in two's complement notation, |-128<=b<128|. This command
changes the current |x|~spacing and moves right by |b|.

\yskip\hang|@!x2| 154 |b[2]|. Same as |x1|, but |b| is two bytes long,
|-32768<=b<32768|.

\yskip\hang|@!x3| 155 |b[3]|. Same as |x1|, but |b| is three bytes long,
|@t$-2^{23}$@><=b<@t$2^{23}$@>|.

\yskip\hang|@!x4| 156 |b[4]|. Same as |x1|, but |b| is four bytes long,
|@t$-2^{31}$@><=b<@t$2^{31}$@>|.

\yskip\hang|down1| 157 |a[1]|. Set |v:=v+a|, i.e., move down |a| units.
The parameter is a signed number in two's complement notation, |-128<=a<128|;
if |a<0|, the reference point moves up.

\yskip\hang|@!down2| 158 |a[2]|. Same as |down1|, except that |a| is a
two-byte quantity in the range |-32768<=a<32768|.

\yskip\hang|@!down3| 159 |a[3]|. Same as |down1|, except that |a| is a
three-byte quantity in the range |@t$-2^{23}$@><=a<@t$2^{23}$@>|.

\yskip\hang|@!down4| 160 |a[4]|. Same as |down1|, except that |a| is a
four-byte quantity in the range |@t$-2^{31}$@><=a<@t$2^{31}$@>|.

\yskip\hang|y0| 161. Set |v:=v+y|; i.e., move down |y| units. With luck,
this parameterless command will usually suffice, because the same kind of motion
will occur several times in succession; the following commands explain how
|y| gets particular values.

\yskip\hang|y1| 162 |a[1]|. Set |y:=a| and |v:=v+a|. The value of |a| is a
signed quantity in two's complement notation, |-128<=a<128|. This command
changes the current |y|~spacing and moves down by |a|.

\yskip\hang|@!y2| 163 |a[2]|. Same as |y1|, but |a| is two bytes long,
|-32768<=a<32768|.

\yskip\hang|@!y3| 164 |a[3]|. Same as |y1|, but |a| is three bytes long,
|@t$-2^{23}$@><=a<@t$2^{23}$@>|.

\yskip\hang|@!y4| 165 |a[4]|. Same as |y1|, but |a| is four bytes long,
|@t$-2^{31}$@><=a<@t$2^{31}$@>|.

\yskip\hang|z0| 166. Set |v:=v+z|; i.e., move down |z| units. The `|z|' commands
are like the `|y|' commands except that they involve |z| instead of |y|.

\yskip\hang|z1| 167 |a[1]|. Set |z:=a| and |v:=v+a|. The value of |a| is a
signed quantity in two's complement notation, |-128<=a<128|. This command
changes the current |z|~spacing and moves down by |a|.

\yskip\hang|@!z2| 168 |a[2]|. Same as |z1|, but |a| is two bytes long,
|-32768<=a<32768|.

\yskip\hang|@!z3| 169 |a[3]|. Same as |z1|, but |a| is three bytes long,
|@t$-2^{23}$@><=a<@t$2^{23}$@>|.

\yskip\hang|@!z4| 170 |a[4]|. Same as |z1|, but |a| is four bytes long,
|@t$-2^{31}$@><=a<@t$2^{31}$@>|.

\yskip\hang|fnt_num_0| 171. Set |f:=0|. Font 0 must previously have been
defined by a \\{fnt\_def} instruction, as explained below.

\yskip\hang\\{fnt\_num\_1} through \\{fnt\_num\_63} (opcodes 172 to 234). Set
|f:=1|, \dots, \hbox{|f:=63|}, respectively.

\yskip\hang|fnt1| 235 |k[1]|. Set |f:=k|. \TeX82 uses this command for font
numbers in the range |64<=k<256|.

\yskip\hang|@!fnt2| 236 |k[2]|. Same as |fnt1|, except that |k|~is two
bytes long, so it is in the range |0<=k<65536|. \TeX82 never generates this
command, but large font numbers may prove useful for specifications of
color or texture, or they may be used for special fonts that have fixed
numbers in some external coding scheme.

\yskip\hang|@!fnt3| 237 |k[3]|. Same as |fnt1|, except that |k|~is three
bytes long, so it can be as large as $2^{24}-1$.

\yskip\hang|@!fnt4| 238 |k[4]|. Same as |fnt1|, except that |k|~is four
bytes long; this is for the really big font numbers (and for the negative ones).

\yskip\hang|xxx1| 239 |k[1]| |x[k]|. This command is undefined in
general; it functions as a $(k+2)$-byte |nop| unless special \.{DVI}-reading
programs are being used. \TeX82 generates |xxx1| when a short enough
\.{\\special} appears, setting |k| to the number of bytes being sent. It
is recommended that |x| be a string having the form of a keyword followed
by possible parameters relevant to that keyword.

\yskip\hang|@!xxx2| 240 |k[2]| |x[k]|. Like |xxx1|, but |0<=k<65536|.

\yskip\hang|@!xxx3| 241 |k[3]| |x[k]|. Like |xxx1|, but |0<=k<@t$2^{24}$@>|.

\yskip\hang|xxx4| 242 |k[4]| |x[k]|. Like |xxx1|, but |k| can be ridiculously
large. \TeX82 uses |xxx4| when sending a string of length 256 or more.

\yskip\hang|fnt_def1| 243 |k[1]| |c[4]| |s[4]| |d[4]| |a[1]| |l[1]| |n[a+l]|.
Define font |k|, where |0<=k<256|; font definitions will be explained shortly.

\yskip\hang|@!fnt_def2| 244 |k[2]| |c[4]| |s[4]| |d[4]| |a[1]| |l[1]| |n[a+l]|.
Define font |k|, where |0<=k<65536|.

\yskip\hang|@!fnt_def3| 245 |k[3]| |c[4]| |s[4]| |d[4]| |a[1]| |l[1]| |n[a+l]|.
Define font |k|, where |0<=k<@t$2^{24}$@>|.

\yskip\hang|@!fnt_def4| 246 |k[4]| |c[4]| |s[4]| |d[4]| |a[1]| |l[1]| |n[a+l]|.
Define font |k|, where |@t$-2^{31}$@><=k<@t$2^{31}$@>|.

\yskip\hang|pre| 247 |i[1]| |num[4]| |den[4]| |mag[4]| |k[1]| |x[k]|.
Beginning of the preamble; this must come at the very beginning of the
file. Parameters |i|, |num|, |den|, |mag|, |k|, and |x| are explained below.

\yskip\hang|post| 248. Beginning of the postamble, see below.

\yskip\hang|post_post| 249. Ending of the postamble, see below.

\yskip\noindent Commands 250--255 are undefined at the present time.

@ @d set_char_0=0 {typeset character 0 and move right}
@d set1=128 {typeset a character and move right}
@d set_rule=132 {typeset a rule and move right}
@d put1==133 {typeset a character without moving}
@d put_rule=137 {typeset a rule}
@d nop=138 {no operation}
@d bop=139 {beginning of page}
@d eop=140 {ending of page}
@d push=141 {save the current positions}
@d pop=142 {restore previous positions}
@d right1==143 {move right}
@d right4==146 {move right, 4 bytes}
@d w0=147 {move right by |w|}
@d w1=148 {move right and set |w|}
@d x0=152 {move right by |x|}
@d x1=153 {move right and set |x|}
@d down1=157 {move down}
@d down4=160 {move down, 4 bytes}
@d y0=161 {move down by |y|}
@d y1=162 {move down and set |y|}
@d z0=166 {move down by |z|}
@d z1=167 {move down and set |z|}
@d fnt_num_0=171 {set current font to 0}
@d fnt1=235 {set current font}
@d xxx1=239 {extension to \.{DVI} primitives}
@d xxx4=242 {potentially long extension to \.{DVI} primitives}
@d fnt_def1=243 {define the meaning of a font number}
@d pre=247 {preamble}
@d post=248 {postamble beginning}
@d post_post=249 {postamble ending}

@ The preamble contains basic information about the file as a whole. As
stated above, there are six parameters:
$$\hbox{|@!i[1]| |@!num[4]| |@!den[4]| |@!mag[4]| |@!k[1]| |@!x[k]|.}$$
The |i| byte identifies \.{DVI} format; currently this byte is always set
to~2. (The value |i=3| is currently used for an extended format that
allows a mixture of right-to-left and left-to-right typesetting.
Some day we will set |i=4|, when \.{DVI} format makes another
incompatible change---perhaps in the year 2048.)

The next two parameters, |num| and |den|, are positive integers that define
the units of measurement; they are the numerator and denominator of a
fraction by which all dimensions in the \.{DVI} file could be multiplied
in order to get lengths in units of $10^{-7}$ meters. Since $\rm 7227{pt} =
254{cm}$, and since \TeX\ works with scaled points where there are $2^{16}$
sp in a point, \TeX\ sets
$|num|/|den|=(254\cdot10^5)/(7227\cdot2^{16})=25400000/473628672$.
@^sp@>

The |mag| parameter is what \TeX\ calls \.{\\mag}, i.e., 1000 times the
desired magnification. The actual fraction by which dimensions are
multiplied is therefore $|mag|\cdot|num|/1000|den|$. Note that if a \TeX\
source document does not call for any `\.{true}' dimensions, and if you
change it only by specifying a different \.{\\mag} setting, the \.{DVI}
file that \TeX\ creates will be completely unchanged except for the value
of |mag| in the preamble and postamble. (Fancy \.{DVI}-reading programs allow
users to override the |mag|~setting when a \.{DVI} file is being printed.)

Finally, |k| and |x| allow the \.{DVI} writer to include a comment, which is not
interpreted further. The length of comment |x| is |k|, where |0<=k<256|.

@d id_byte=2 {identifies the kind of \.{DVI} files described here}

@ Font definitions for a given font number |k| contain further parameters
$$\hbox{|c[4]| |s[4]| |d[4]| |a[1]| |l[1]| |n[a+l]|.}$$
The four-byte value |c| is the check sum that \TeX\ found in the \.{TFM}
file for this font; |c| should match the check sum of the font found by
programs that read this \.{DVI} file.
@^check sum@>

Parameter |s| contains a fixed-point scale factor that is applied to
the character widths in font |k|; font dimensions in \.{TFM} files and
other font files are relative to this quantity, which is called the
``at size'' elsewhere in this documentation. The value of |s| is
always positive and less than $2^{27}$. It is given in the same units
as the other \.{DVI} dimensions, i.e., in sp when \TeX82 has made the
file.  Parameter |d| is similar to |s|; it is the ``design size,'' and
(like~|s|) it is given in \.{DVI} units. Thus, font |k| is to be used
at $|mag|\cdot s/1000d$ times its normal size.

The remaining part of a font definition gives the external name of the font,
which is an ASCII string of length |a+l|. The number |a| is the length
of the ``area'' or directory, and |l| is the length of the font name itself;
the standard local system font area is supposed to be used when |a=0|.
The |n| field contains the area in its first |a| bytes.

Font definitions must appear before the first use of a particular font number.
Once font |k| is defined, it must not be defined again; however, we
shall see below that font definitions appear in the postamble as well as
in the pages, so in this sense each font number is defined exactly twice,
if at all. Like |nop| commands, font definitions can
appear before the first |bop|, or between an |eop| and a |bop|.

@ Sometimes it is desirable to make horizontal or vertical rules line up
precisely with certain features in characters of a font. It is possible to
guarantee the correct matching between \.{DVI} output and the characters
generated by \MF\ by adhering to the following principles: (1)~The \MF\
characters should be positioned so that a bottom edge or left edge that is
supposed to line up with the bottom or left edge of a rule appears at the
reference point, i.e., in row~0 and column~0 of the \MF\ raster. This
ensures that the position of the rule will not be rounded differently when
the pixel size is not a perfect multiple of the units of measurement in
the \.{DVI} file. (2)~A typeset rule of height $a>0$ and width $b>0$
should be equivalent to a \MF-generated character having black pixels in
precisely those raster positions whose \MF\ coordinates satisfy
|0<=x<@t$\alpha$@>b| and |0<=y<@t$\alpha$@>a|, where $\alpha$ is the number
of pixels per \.{DVI} unit.
@:METAFONT}{\MF@>
@^alignment of rules with characters@>
@^rules aligning with characters@>

@ The last page in a \.{DVI} file is followed by `|post|'; this command
introduces the postamble, which summarizes important facts that \TeX\ has
accumulated about the file, making it possible to print subsets of the data
with reasonable efficiency. The postamble has the form
$$\vbox{\halign{\hbox{#\hfil}\cr
  |post| |p[4]| |num[4]| |den[4]| |mag[4]| |l[4]| |u[4]| |s[2]| |t[2]|\cr
  $\langle\,$font definitions$\,\rangle$\cr
  |post_post| |q[4]| |i[1]| 223's$[{\G}4]$\cr}}$$
Here |p| is a pointer to the final |bop| in the file. The next three
parameters, |num|, |den|, and |mag|, are duplicates of the quantities that
appeared in the preamble.

Parameters |l| and |u| give respectively the height-plus-depth of the tallest
page and the width of the widest page, in the same units as other dimensions
of the file. These numbers might be used by a \.{DVI}-reading program to
position individual ``pages'' on large sheets of film or paper; however,
the standard convention for output on normal size paper is to position each
page so that the upper left-hand corner is exactly one inch from the left
and the top. Experience has shown that it is unwise to design \.{DVI}-to-printer
software that attempts cleverly to center the output; a fixed position of
the upper left corner is easiest for users to understand and to work with.
Therefore |l| and~|u| are often ignored.

Parameter |s| is the maximum stack depth (i.e., the largest excess of
|push| commands over |pop| commands) needed to process this file. Then
comes |t|, the total number of pages (|bop| commands) present.

The postamble continues with font definitions, which are any number of
\\{fnt\_def} commands as described above, possibly interspersed with |nop|
commands. Each font number that is used in the \.{DVI} file must be defined
exactly twice: Once before it is first selected by a \\{fnt} command, and once
in the postamble.

@ The last part of the postamble, following the |post_post| byte that
signifies the end of the font definitions, contains |q|, a pointer to the
|post| command that started the postamble.  An identification byte, |i|,
comes next; this currently equals~2, as in the preamble.

The |i| byte is followed by four or more bytes that are all equal to
the decimal number 223 (i.e., @'337 in octal). \TeX\ puts out four to seven of
these trailing bytes, until the total length of the file is a multiple of
four bytes, since this works out best on machines that pack four bytes per
word; but any number of 223's is allowed, as long as there are at least four
of them. In effect, 223 is a sort of signature that is added at the very end.
@^Fuchs, David Raymond@>

This curious way to finish off a \.{DVI} file makes it feasible for
\.{DVI}-reading programs to find the postamble first, on most computers,
even though \TeX\ wants to write the postamble last. Most operating
systems permit random access to individual words or bytes of a file, so
the \.{DVI} reader can start at the end and skip backwards over the 223's
until finding the identification byte. Then it can back up four bytes, read
|q|, and move to byte |q| of the file. This byte should, of course,
contain the value 248 (|post|); now the postamble can be read, so the
\.{DVI} reader can discover all the information needed for typesetting the
pages. Note that it is also possible to skip through the \.{DVI} file at
reasonably high speed to locate a particular page, if that proves
desirable. This saves a lot of time, since \.{DVI} files used in production
jobs tend to be large.

Unfortunately, however, standard \PASCAL\ does not include the ability to
@^system dependencies@>
access a random position in a file, or even to determine the length of a file.
Almost all systems nowadays provide the necessary capabilities, so \.{DVI}
format has been designed to work most efficiently with modern operating systems.
But if \.{DVI} files have to be processed under the restrictions of standard
\PASCAL, one can simply read them from front to back, since the necessary
header information is present in the preamble and in the font definitions.
(The |l| and |u| and |s| and |t| parameters, which appear only in the
postamble, are ``frills'' that are handy but not absolutely necessary.)

@* \[32] Shipping pages out.
After considering \TeX's eyes and stomach, we come now to the bowels.
@^bowels@>

The |ship_out| procedure is given a pointer to a box; its mission is
to describe that box in \.{DVI} form, outputting a ``page'' to |dvi_file|.
The \.{DVI} coordinates $(h,v)=(0,0)$ should correspond to the upper left
corner of the box being shipped.

Since boxes can be inside of boxes inside of boxes, the main work of
|ship_out| is done by two mutually recursive routines, |hlist_out|
and |vlist_out|, which traverse the hlists and vlists inside of horizontal
and vertical boxes.

As individual pages are being processed, we need to accumulate
information about the entire set of pages, since such statistics must be
reported in the postamble. The global variables |total_pages|, |max_v|,
|max_h|, |max_push|, and |last_bop| are used to record this information.

The variable |doing_leaders| is |true| while leaders are being output.
The variable |dead_cycles| contains the number of times an output routine
has been initiated since the last |ship_out|.

A few additional global variables are also defined here for use in
|vlist_out| and |hlist_out|. They could have been local variables, but
that would waste stack space when boxes are deeply nested, since the
values of these variables are not needed during recursive calls.
@^recursion@>

@<Glob...@>=
@!total_pages:integer; {the number of pages that have been shipped out}
@!max_v:scaled; {maximum height-plus-depth of pages shipped so far}
@!max_h:scaled; {maximum width of pages shipped so far}
@!max_push:integer; {deepest nesting of |push| commands encountered so far}
@!last_bop:integer; {location of previous |bop| in the \.{DVI} output}
@!dead_cycles:integer; {recent outputs that didn't ship anything out}
@!doing_leaders:boolean; {are we inside a leader box?}
@#
@!c,@!f:integer; {character and font in current |char_node|}
@!oval,@!ocmd:integer; {used by |out_cmd| for generating
  |set|, |fnt| and |fnt_def| commands}
@!rule_ht,@!rule_dp,@!rule_wd:scaled; {size of current rule being output}
@!g:pointer; {current glue specification}
@!lq,@!lr:integer; {quantities used in calculations for leaders}

@ @<Set init...@>=
total_pages:=0; max_v:=0; max_h:=0; max_push:=0; last_bop:=-1;
doing_leaders:=false; dead_cycles:=0; cur_s:=-1;

@ The \.{DVI} bytes are output to a buffer instead of being written directly
to the output file. This makes it possible to reduce the overhead of
subroutine calls, thereby measurably speeding up the computation, since
output of \.{DVI} bytes is part of \TeX's inner loop. And it has another
advantage as well, since we can change instructions in the buffer in order to
make the output more compact. For example, a `|down2|' command can be
changed to a `|y2|', thereby making a subsequent `|y0|' command possible,
saving two bytes.

The output buffer is divided into two parts of equal size; the bytes found
in |dvi_buf[0..half_buf-1]| constitute the first half, and those in
|dvi_buf[half_buf..dvi_buf_size-1]| constitute the second. The global
variable |dvi_ptr| points to the position that will receive the next
output byte. When |dvi_ptr| reaches |dvi_limit|, which is always equal
to one of the two values |half_buf| or |dvi_buf_size|, the half buffer that
is about to be invaded next is sent to the output and |dvi_limit| is
changed to its other value. Thus, there is always at least a half buffer's
worth of information present, except at the very beginning of the job.

Bytes of the \.{DVI} file are numbered sequentially starting with 0;
the next byte to be generated will be number |dvi_offset+dvi_ptr|.
A byte is present in the buffer only if its number is |>=dvi_gone|.

@<Types...@>=
@!dvi_index=0..dvi_buf_size; {an index into the output buffer}

@ Some systems may find it more efficient to make |dvi_buf| a |packed|
array, since output of four bytes at once may be facilitated.
@^system dependencies@>

@<Glob...@>=
@!dvi_buf:array[dvi_index] of real_eight_bits; {buffer for \.{DVI} output}
@!half_buf:dvi_index; {half of |dvi_buf_size|}
@!dvi_limit:dvi_index; {end of the current half buffer}
@!dvi_ptr:dvi_index; {the next available buffer address}
@!dvi_offset:integer; {|dvi_buf_size| times the number of times the
  output buffer has been fully emptied}
@!dvi_gone:integer; {the number of bytes already output to |dvi_file|}

@ Initially the buffer is all in one piece; we will output half of it only
after it first fills up.

@<Set init...@>=
half_buf:=dvi_buf_size div 2; dvi_limit:=dvi_buf_size; dvi_ptr:=0;
dvi_offset:=0; dvi_gone:=0;

@ The actual output of |dvi_buf[a..b]| to |dvi_file| is performed by calling
|write_dvi(a,b)|. For best results, this procedure should be optimized to
run as fast as possible on each particular system, since it is part of
\TeX's inner loop. It is safe to assume that |a| and |b+1| will both be
multiples of 4 when |write_dvi(a,b)| is called; therefore it is possible on
many machines to use efficient methods to pack four bytes per word and to
output an array of words with one system call.
@^system dependencies@>
@^inner loop@>
@^defecation@>

@p procedure write_dvi(@!a,@!b:dvi_index);
var k:dvi_index;
begin for k:=a to b do write(dvi_file,dvi_buf[k]);
end;

@ To put a byte in the buffer without paying the cost of invoking a procedure
each time, we use the macro |dvi_out|.

@d dvi_out(#)==@+begin dvi_buf[dvi_ptr]:=#; incr(dvi_ptr);
  if dvi_ptr=dvi_limit then dvi_swap;
  end

@p procedure dvi_swap; {outputs half of the buffer}
begin if dvi_limit=dvi_buf_size then
  begin write_dvi(0,half_buf-1); dvi_limit:=half_buf;
  dvi_offset:=dvi_offset+dvi_buf_size; dvi_ptr:=0;
  end
else  begin write_dvi(half_buf,dvi_buf_size-1); dvi_limit:=dvi_buf_size;
  end;
dvi_gone:=dvi_gone+half_buf;
end;

@ Here is how we clean out the buffer when \TeX\ is all through; |dvi_ptr|
will be a multiple of~4.

@<Empty the last bytes out of |dvi_buf|@>=
if dvi_limit=half_buf then write_dvi(half_buf,dvi_buf_size-1);
if dvi_ptr>0 then write_dvi(0,dvi_ptr-1)

@ The |dvi_four| procedure outputs four bytes in two's complement notation,
without risking arithmetic overflow.

@p procedure dvi_four(@!x:integer);
begin if x>=0 then dvi_out(x div @'100000000)
else  begin x:=x+@'10000000000;
  x:=x+@'10000000000;
  dvi_out((x div @'100000000) + 128);
  end;
x:=x mod @'100000000; dvi_out(x div @'200000);
x:=x mod @'200000; dvi_out(x div @'400);
dvi_out(x mod @'400);
end;

@ A mild optimization of the output is performed by the |dvi_pop|
routine, which issues a |pop| unless it is possible to cancel a
`|push| |pop|' pair. The parameter to |dvi_pop| is the byte address
following the old |push| that matches the new |pop|.

@p procedure dvi_pop(@!l:integer);
begin if (l=dvi_offset+dvi_ptr)and(dvi_ptr>0) then decr(dvi_ptr)
else dvi_out(pop);
end;

@ Here's a procedure that outputs a font definition. $\Omega$ allows
more than 256 different fonts per job, so the right font definition
command must be selected.

@d Incr_Decr(#) == #
@d Incr(#) == #:=#+Incr_Decr {increase a variable}
@d Decr(#) == #:=#-Incr_Decr {decrease a variable}

@d dvi_debug_out(#)==begin
dvi_out(#);
end

@d out_cmd ==
begin
if (oval<@"100)and(oval>=0) then begin
  if (ocmd<>set1)or(oval>127) then begin
  if (ocmd=fnt1)and(oval<64) then Incr(oval)(fnt_num_0) @+ else dvi_debug_out(ocmd);
  end;
  end
else
  begin if (oval<@"10000)and(oval>=0) then dvi_debug_out(ocmd+1) @+ else @;
    begin if (oval<@"1000000)and(oval>=0) then dvi_debug_out(ocmd+2) @+ else @;
      begin dvi_debug_out(ocmd+3);
      if oval>=0 then dvi_debug_out(oval div @"1000000)
      else  begin Incr(oval)(@"40000000); Incr(oval)(@"40000000);
        dvi_debug_out((oval div @"1000000) + 128); oval:=oval mod @"1000000;
        end;
      dvi_debug_out(oval div @"10000); oval:=oval mod @"10000;
      end;
    dvi_debug_out(oval div @"10000); oval:=oval mod @"10000;
    end;
  dvi_debug_out(oval div @"100); oval:=oval mod @"100;
  end;
dvi_debug_out(oval)
end

@p procedure dvi_font_def(@!f:internal_font_number);
var k:pool_pointer; {index into |str_pool|}
fa:^packed_ASCII_code;
begin
oval:=f-font_base-1; ocmd:= fnt_def1; out_cmd;@/
dvi_out(font_check_0(f));
dvi_out(font_check_1(f));
dvi_out(font_check_2(f));
dvi_out(font_check_3(f));@/
dvi_four(font_size(f));
dvi_four(font_dsize(f));@/
dvi_out(0); { |font_area(f)| is unused }
dvi_out(strlen(font_name(f)));
@<Output the font name whose internal number is |f|@>;
end;

@ @<Output the font name whose internal number is |f|@>=
fa := get_font_name(f); k := 0;
while fa[k]<>0 do begin dvi_out(fa[k]); incr(k); end

@ Versions of \TeX\ intended for small computers might well choose to omit
the ideas in the next few parts of this program, since it is not really
necessary to optimize the \.{DVI} code by making use of the |w0|, |x0|,
|y0|, and |z0| commands. Furthermore, the algorithm that we are about to
describe does not pretend to give an optimum reduction in the length
of the \.{DVI} code; after all, speed is more important than compactness.
But the method is surprisingly effective, and it takes comparatively little
time.

We can best understand the basic idea by first considering a simpler problem
that has the same essential characteristics. Given a sequence of digits,
say $3\,1\,4\,1\,5\,9\,2\,6\,5\,3\,5\,8\,9$, we want to assign subscripts
$d$, $y$, or $z$ to each digit so as to maximize the number of ``$y$-hits''
and ``$z$-hits''; a $y$-hit is an instance of two appearances of the same
digit with the subscript $y$, where no $y$'s intervene between the two
appearances, and a $z$-hit is defined similarly. For example, the sequence
above could be decorated with subscripts as follows:
$$3_z\,1_y\,4_d\,1_y\,5_y\,9_d\,2_d\,6_d\,5_y\,3_z\,5_y\,8_d\,9_d.$$
There are three $y$-hits ($1_y\ldots1_y$ and $5_y\ldots5_y\ldots5_y$) and
one $z$-hit ($3_z\ldots3_z$); there are no $d$-hits, since the two appearances
of $9_d$ have $d$'s between them, but we don't count $d$-hits so it doesn't
matter how many there are. These subscripts are analogous to the \.{DVI}
commands called \\{down}, $y$, and $z$, and the digits are analogous to
different amounts of vertical motion; a $y$-hit or $z$-hit corresponds to
the opportunity to use the one-byte commands |y0| or |z0| in a \.{DVI} file.

\TeX's method of assigning subscripts works like this: Append a new digit,
say $\delta$, to the right of the sequence. Now look back through the
sequence until one of the following things happens: (a)~You see
$\delta_y$ or $\delta_z$, and this was the first time you encountered a
$y$ or $z$ subscript, respectively.  Then assign $y$ or $z$ to the new
$\delta$; you have scored a hit. (b)~You see $\delta_d$, and no $y$
subscripts have been encountered so far during this search.  Then change
the previous $\delta_d$ to $\delta_y$ (this corresponds to changing a
command in the output buffer), and assign $y$ to the new $\delta$; it's
another hit.  (c)~You see $\delta_d$, and a $y$ subscript has been seen
but not a $z$.  Change the previous $\delta_d$ to $\delta_z$ and assign
$z$ to the new $\delta$. (d)~You encounter both $y$ and $z$ subscripts
before encountering a suitable $\delta$, or you scan all the way to the
front of the sequence. Assign $d$ to the new $\delta$; this assignment may
be changed later.

The subscripts $3_z\,1_y\,4_d\ldots\,$ in the example above were, in fact,
produced by this procedure, as the reader can verify. (Go ahead and try it.)

@ In order to implement such an idea, \TeX\ maintains a stack of pointers
to the \\{down}, $y$, and $z$ commands that have been generated for the
current page. And there is a similar stack for \\{right}, |w|, and |x|
commands. These stacks are called the down stack and right stack, and their
top elements are maintained in the variables |down_ptr| and |right_ptr|.

Each entry in these stacks contains four fields: The |width| field is
the amount of motion down or to the right; the |location| field is the
byte number of the \.{DVI} command in question (including the appropriate
|dvi_offset|); the |vlink| field points to the next item below this one
on the stack; and the |vinfo| field encodes the options for possible change
in the \.{DVI} command.

@d location(#)==vmem(#+1).int {\.{DVI} byte number for a movement command}

@<Glob...@>=
@!down_ptr,@!right_ptr:pointer; {heads of the down and right stacks}

@ @<Set init...@>=
down_ptr:=null; right_ptr:=null;

@ Here is a subroutine that produces a \.{DVI} command for some specified
downward or rightward motion. It has two parameters: |w| is the amount
of motion, and |o| is either |down1| or |right1|. We use the fact that
the command codes have convenient arithmetic properties: |y1-down1=w1-right1|
and |z1-down1=x1-right1|.

@d dvi_set_end(#)==dvi.h := dvi.h + (#); end
@d dvi_set(#)==begin synch_dvi_with_pos; oval:=#; ocmd:=set1; out_cmd; dvi_set_end
@d dvi_put(#)==begin synch_dvi_with_pos; oval:=#; ocmd:=put1; out_cmd; end
@d dvi_set_rule_end(#)==dvi_four(#); dvi.h := dvi.h + (#); end
@d dvi_set_rule(#)==begin synch_dvi_with_pos; dvi_out(set_rule); dvi_four(#); dvi_set_rule_end
@d dvi_put_rule_end(#)==dvi_four(#); end
@d dvi_put_rule(#)==begin synch_dvi_with_pos; dvi_out(put_rule); dvi_four(#); dvi_put_rule_end

@p procedure movement(@!w:scaled;@!o:eight_bits);
label exit,found,not_found,2,1;
var mstate:small_number; {have we seen a |y| or |z|?}
@!p,@!q:pointer; {current and top nodes on the stack}
@!k:integer; {index into |dvi_buf|, modulo |dvi_buf_size|}
begin
if false then begin
  q:=new_node(movement_node,0); {new node for the top of the stack}
  width(q):=w; location(q):=dvi_offset+dvi_ptr;
  if o=down1 then
    begin vlink(q):=down_ptr; down_ptr:=q;
    end
  else  begin vlink(q):=right_ptr; right_ptr:=q;
    end;
  @<Look at the other stack entries until deciding what sort of \.{DVI} command
    to generate; |goto found| if node |p| is a ``hit''@>;
end;
@<Generate a |down| or |right| command for |w| and |return|@>;
found: @<Generate a |y0| or |z0| command in order to reuse a previous
  appearance of~|w|@>;
exit:end;

@ The |vinfo| fields in the entries of the down stack or the right stack
have six possible settings: |y_here| or |z_here| mean that the \.{DVI}
command refers to |y| or |z|, respectively (or to |w| or |x|, in the
case of horizontal motion); |yz_OK| means that the \.{DVI} command is
\\{down} (or \\{right}) but can be changed to either |y| or |z| (or
to either |w| or |x|); |y_OK| means that it is \\{down} and can be changed
to |y| but not |z|; |z_OK| is similar; and |d_fixed| means it must stay
\\{down}.

The four settings |yz_OK|, |y_OK|, |z_OK|, |d_fixed| would not need to
be distinguished from each other if we were simply solving the
digit-subscripting problem mentioned above. But in \TeX's case there is
a complication because of the nested structure of |push| and |pop|
commands. Suppose we add parentheses to the digit-subscripting problem,
redefining hits so that $\delta_y\ldots \delta_y$ is a hit if all $y$'s between
the $\delta$'s are enclosed in properly nested parentheses, and if the
parenthesis level of the right-hand $\delta_y$ is deeper than or equal to
that of the left-hand one. Thus, `(' and `)' correspond to `|push|'
and `|pop|'. Now if we want to assign a subscript to the final 1 in the
sequence
$$2_y\,7_d\,1_d\,(\,8_z\,2_y\,8_z\,)\,1$$
we cannot change the previous $1_d$ to $1_y$, since that would invalidate
the $2_y\ldots2_y$ hit. But we can change it to $1_z$, scoring a hit
since the intervening $8_z$'s are enclosed in parentheses.

The program below removes movement nodes that are introduced after a |push|,
before it outputs the corresponding |pop|.

@d y_here=1 {|vinfo| when the movement entry points to a |y| command}
@d z_here=2 {|vinfo| when the movement entry points to a |z| command}
@d yz_OK=3 {|vinfo| corresponding to an unconstrained \\{down} command}
@d y_OK=4 {|vinfo| corresponding to a \\{down} that can't become a |z|}
@d z_OK=5 {|vinfo| corresponding to a \\{down} that can't become a |y|}
@d d_fixed=6 {|vinfo| corresponding to a \\{down} that can't change}

@ When the |movement| procedure gets to the label |found|, the value of
|vinfo(p)| will be either |y_here| or |z_here|. If it is, say, |y_here|,
the procedure generates a |y0| command (or a |w0| command), and marks
all |vinfo| fields between |q| and |p| so that |y| is not OK in that range.

@<Generate a |y0| or |z0| command...@>=
vinfo(q):=vinfo(p);
if vinfo(q)=y_here then
  begin dvi_out(o+y0-down1); {|y0| or |w0|}
  while vlink(q)<>p do
    begin q:=vlink(q);
    case vinfo(q) of
    yz_OK: vinfo(q):=z_OK;
    y_OK: vinfo(q):=d_fixed;
    othercases do_nothing
    endcases;
    end;
  end
else  begin dvi_out(o+z0-down1); {|z0| or |x0|}
  while vlink(q)<>p do
    begin q:=vlink(q);
    case vinfo(q) of
    yz_OK: vinfo(q):=y_OK;
    z_OK: vinfo(q):=d_fixed;
    othercases do_nothing
    endcases;
    end;
  end

@ @<Generate a |down| or |right|...@>=
if abs(w)>=@'40000000 then
  begin dvi_out(o+3); {|down4| or |right4|}
  dvi_four(w); return;
  end;
if abs(w)>=@'100000 then
  begin dvi_out(o+2); {|down3| or |right3|}
  if w<0 then w:=w+@'100000000;
  dvi_out(w div @'200000); w:=w mod @'200000; goto 2;
  end;
if abs(w)>=@'200 then
  begin dvi_out(o+1); {|down2| or |right2|}
  if w<0 then w:=w+@'200000;
  goto 2;
  end;
dvi_out(o); {|down1| or |right1|}
if w<0 then w:=w+@'400;
goto 1;
2: dvi_out(w div @'400);
1: dvi_out(w mod @'400); return

@ As we search through the stack, we are in one of three states,
|y_seen|, |z_seen|, or |none_seen|, depending on whether we have
encountered |y_here| or |z_here| nodes. These states are encoded as
multiples of 6, so that they can be added to the |info| fields for quick
decision-making.
@^inner loop@>

@d none_seen=0 {no |y_here| or |z_here| nodes have been encountered yet}
@d y_seen=6 {we have seen |y_here| but not |z_here|}
@d z_seen=12 {we have seen |z_here| but not |y_here|}

@<Look at the other stack entries until deciding...@>=
p:=vlink(q); mstate:=none_seen;
while p<>null do
  begin if width(p)=w then @<Consider a node with matching width;
    |goto found| if it's a hit@>
  else  case mstate+vinfo(p) of
    none_seen+y_here: mstate:=y_seen;
    none_seen+z_here: mstate:=z_seen;
    y_seen+z_here,z_seen+y_here: goto not_found;
    othercases do_nothing
    endcases;
  p:=vlink(p);
  end;
not_found:

@ We might find a valid hit in a |y| or |z| byte that is already gone
from the buffer. But we can't change bytes that are gone forever; ``the
moving finger writes, $\ldots\,\,$.''

@<Consider a node with matching width...@>=
case mstate+vinfo(p) of
none_seen+yz_OK,none_seen+y_OK,z_seen+yz_OK,z_seen+y_OK:@t@>@;@/
  if location(p)<dvi_gone then goto not_found
  else @<Change buffered instruction to |y| or |w| and |goto found|@>;
none_seen+z_OK,y_seen+yz_OK,y_seen+z_OK:@t@>@;@/
  if location(p)<dvi_gone then goto not_found
  else @<Change buffered instruction to |z| or |x| and |goto found|@>;
none_seen+y_here,none_seen+z_here,y_seen+z_here,z_seen+y_here: goto found;
othercases do_nothing
endcases

@ @<Change buffered instruction to |y| or |w| and |goto found|@>=
begin k:=location(p)-dvi_offset;
if k<0 then k:=k+dvi_buf_size;
dvi_buf[k]:=dvi_buf[k]+y1-down1;
vinfo(p):=y_here; goto found;
end

@ @<Change buffered instruction to |z| or |x| and |goto found|@>=
begin k:=location(p)-dvi_offset;
if k<0 then k:=k+dvi_buf_size;
dvi_buf[k]:=dvi_buf[k]+z1-down1;
vinfo(p):=z_here; goto found;
end

@ In case you are wondering when all the movement nodes are removed from
\TeX's memory, the answer is that they are recycled just before
|hlist_out| and |vlist_out| finish outputting a box. This restores the
down and right stacks to the state they were in before the box was output,
except that some |vinfo|'s may have become more restrictive.

@p procedure prune_movements(@!l:integer);
  {delete movement nodes with |location>=l|}
label done,exit;
var p:pointer; {node being deleted}
begin while down_ptr<>null do
  begin if location(down_ptr)<l then goto done;
  p:=down_ptr; down_ptr:=vlink(p); flush_node(p);
  end;
done: while right_ptr<>null do
  begin if location(right_ptr)<l then return;
  p:=right_ptr; right_ptr:=vlink(p); flush_node(p);
  end;
exit:end;

@ The actual distances by which we want to move might be computed as the
sum of several separate movements. For example, there might be several
glue nodes in succession, or we might want to move right by the width of
some box plus some amount of glue. More importantly, the baselineskip
distances are computed in terms of glue together with the depth and
height of adjacent boxes, and we want the \.{DVI} file to lump these
three quantities together into a single motion.

Therefore, \TeX\ maintains two pairs of global variables: |dvi.h| and |dvi.v|
are the |h| and |v| coordinates corresponding to the commands actually
output to the \.{DVI} file, while |cur.h| and |cur.v| are the coordinates
corresponding to the current state of the output routines. Coordinate
changes will accumulate in |cur.h| and |cur.v| without being reflected
in the output, until such a change becomes necessary or desirable; we
can call the |movement| procedure whenever we want to make |dvi.h=pos.h|
or |dvi.v=pos.v|.

The current font reflected in the \.{DVI} output is called |dvi_f|;
there is no need for a `\\{cur\_f}' variable.

The depth of nesting of |hlist_out| and |vlist_out| is called |cur_s|;
this is essentially the depth of |push| commands in the \.{DVI} output.

@d synch_h==if pos.h <> dvi.h then begin
    movement(pos.h - dvi.h, right1);
    dvi.h := pos.h;
    end

@d synch_v==if pos.v <> dvi.v then begin
    movement(dvi.v - pos.v, down1);
    dvi.v := pos.v;
    end

@d synch_dvi_with_pos==begin
    synch_h; synch_v;
    end

@d synch_pos_with_cur==case box_direction(dvi_direction) of
    dir_TL_: begin pos.h := box_pos.h + cur.h; pos.v := box_pos.v - cur.v; end;
    dir_TR_: begin pos.h := box_pos.h - cur.h; pos.v := box_pos.v - cur.v; end;
    dir_BL_: begin pos.h := box_pos.h + cur.h; pos.v := box_pos.v + cur.v; end;
    dir_BR_: begin pos.h := box_pos.h - cur.h; pos.v := box_pos.v + cur.v; end;
    dir_LT_: begin pos.h := box_pos.h + cur.v; pos.v := box_pos.v - cur.h; end;
    dir_RT_: begin pos.h := box_pos.h - cur.v; pos.v := box_pos.v - cur.h; end;
    dir_LB_: begin pos.h := box_pos.h + cur.v; pos.v := box_pos.v + cur.h; end;
    dir_RB_: begin pos.h := box_pos.h - cur.v; pos.v := box_pos.v + cur.h; end;
    end

@d synch_dvi_with_cur==begin
    synch_pos_with_cur;
    synch_dvi_with_pos;
end

@d set_to_zero(#)==begin #.h := 0; #.v := 0; end

@ @p function synch_p_with_c(cur: scaledpos): scaledpos;
var pos: scaledpos;
begin
  synch_pos_with_cur;
  synch_p_with_c := pos;
end;

@ @<Types...@>=
@!scaledpos = record
    h, v: scaled;
    end;

@ @<Glob...@>=
@!cur: scaledpos; {\TeX\ position relative to origin of the surrounding box, in box coordinate system}
@!box_pos: scaledpos; {position of box origin in page coordinates}
@!pos: scaledpos; {global position on page, in $\rm sp$, from lower left page corner}
@!dvi: scaledpos; {a \.{DVI} position in page coordinates, in sync with DVI file}
@!dvi_f:internal_font_number; {the current font}
@!cur_s:integer; {current depth of output box nesting, initially $-1$}

@ @<Calculate DVI page dimensions and margins@>=
if page_width > 0 then
    cur_page_size.h := page_width
else
    case box_direction(dvi_direction) of
    dir_TL_, dir_BL_: cur_page_size.h := width(p) + 2 * page_left_offset;
    dir_TR_, dir_BR_: cur_page_size.h := width(p) + 2 * page_right_offset;
    dir_LT_, dir_LB_: cur_page_size.h := height(p) + depth(p) + 2 * page_left_offset;
    dir_RT_, dir_RB_: cur_page_size.h := height(p) + depth(p) + 2 * page_right_offset;
    end;
if page_height > 0 then
    cur_page_size.v := page_height
else
    case box_direction(dvi_direction) of
    dir_TL_, dir_TR_: cur_page_size.v := height(p) + depth(p) + 2 * page_top_offset;
    dir_BL_, dir_BR_: cur_page_size.v := height(p) + depth(p) + 2 * page_bottom_offset;
    dir_LT_, dir_RT_: cur_page_size.v := width(p) + 2 * page_top_offset;
    dir_LB_, dir_RB_: cur_page_size.v := width(p) + 2 * page_bottom_offset;
    end

@ @<Initialize variables as |ship_out| begins@>=
set_to_zero(dvi); set_to_zero(cur); dvi_f:=null_font;
@<Calculate DVI page dimensions and margins@>;
ensure_dvi_open;
if total_pages=0 then
  begin dvi_out(pre); dvi_out(id_byte); {output the preamble}
@^preamble of \.{DVI} file@>
  dvi_four(25400000); dvi_four(473628672); {conversion ratio for sp}
  prepare_mag; dvi_four(mag); {magnification factor is frozen}
  old_setting:=selector; selector:=new_string;
  print(" LuaTeX output "); print_int(year); print_char(".");
  print_two(month); print_char("."); print_two(day);
  print_char(":"); print_two(time div 60);
  print_two(time mod 60);
  selector:=old_setting; dvi_out(cur_length);
  for s:=str_start_macro(str_ptr) to pool_ptr-1 do dvi_out(so(str_pool[s]));
  pool_ptr:=str_start_macro(str_ptr); {flush the current string}
  end

@ When |hlist_out| is called, its duty is to output the box represented
by the |hlist_node| pointed to by |temp_ptr|. The reference point of that
box has coordinates |(cur.h,cur.v)|.

Similarly, when |vlist_out| is called, its duty is to output the box represented
by the |vlist_node| pointed to by |temp_ptr|. The reference point of that
box has coordinates |(cur.h,cur.v)|.
@^recursion@>

@p procedure@?vlist_out; forward; {|hlist_out| and |vlist_out| are mutually
  recursive}

@ The recursive procedures |hlist_out| and |vlist_out| each have a local variable
|save_dvi| to hold the value of |dvi| just before
entering a new level of recursion.  In effect, the value of |save_dvi|
on \TeX's run-time stack corresponds to the values of |h| and |v|
that a \.{DVI}-reading program will push onto its coordinate stack.

@d move_past=13 {go to this label when advancing past glue or a rule}
@d fin_rule=14 {go to this label to finish processing a rule}
@d next_p=15 {go to this label when finished with node |p|}

@p @t\4@>@<Declare procedures needed in |hlist_out|, |vlist_out|@>@t@>@/
procedure hlist_out; {output an |hlist_node| box}
label move_past, fin_rule, next_p;
var base_line: scaled; {the baseline coordinate for this box}
c_wd,c_ht,c_dp: scaled;
  {the real width, height and depth of the character}
w: scaled; { temporary value for directional width calculation }
dir_nest: integer; { for tracking nested direction nodes }
edge_v: scaled;
edge_h: scaled;
effective_horizontal: scaled;
basepoint_horizontal: scaled;
basepoint_vertical: scaled;
save_direction: integer;
dir_ptr,dir_tmp:pointer;
@!left_edge: scaled; {the left coordinate for this box}
@!save_h: scaled; {what |cur.h| should pop to}
@!save_dvi: scaledpos; {what |dvi| should pop to}
@!save_box_pos: scaledpos; {what |box_pos| should pop to}
@!this_box: pointer; {pointer to containing box}
@!g_order: glue_ord; {applicable order of infinity for glue}
@!g_sign: normal..shrinking; {selects type of glue}
@!p,q:pointer; {current position in the hlist}
@!save_loc:integer; {\.{DVI} byte location upon entry}
@!leader_box:pointer; {the leader box being replicated}
@!leader_wd:scaled; {width of leader box being replicated}
@!lx:scaled; {extra space between leader boxes}
@!outer_doing_leaders:boolean; {were we doing leaders?}
@!edge:scaled; {right edge of sub-box or leader space}
@!glue_temp:real; {glue value before rounding}
@!cur_glue:real; {glue seen so far}
@!save_cur_glue:real; { saved version, for direction switch }
@!cur_g:scaled; {rounded equivalent of |cur_glue| times the glue ratio}
@!save_cur_g:scaled; { saved version, for direction switch }
begin cur_g:=0; cur_glue:=float_constant(0);
this_box:=temp_ptr; g_order:=glue_order(this_box);
g_sign:=glue_sign(this_box); p:=list_ptr(this_box);
set_to_zero(cur); box_pos:=pos;
save_direction:=dvi_direction;
dvi_direction:=box_dir(this_box);
@<DIR: Initialize |dir_ptr| for |ship_out|@>;
incr(cur_s);
if cur_s>0 then dvi_out(push);
if cur_s>max_push then max_push:=cur_s;
save_loc:=dvi_offset+dvi_ptr; base_line:=cur.v; left_edge:=cur.h;
@<Start hlist {\sl Sync\TeX} information record@>;
while p<>null do @<Output node |p| for |hlist_out| and move to the next node,
  maintaining the condition |cur.v=base_line|@>;
@<Finish hlist {\sl Sync\TeX} information record@>;
prune_movements(save_loc);
if cur_s>0 then dvi_pop(save_loc);
decr(cur_s);
dvi_direction:=save_direction;
@<DIR: Reset |dir_ptr|@>;
end;

@ This is a cacheing attempt

@d charinfo_width(#)==#.ci_wd
@d charinfo_height(#)==#.ci_ht
@d charinfo_depth(#)==#.ci_dp

@<Types...@>=
charinfo_short = packed record@;@/
  @!ci_wd:scaled;
  @!ci_ht:scaled;
  @!ci_dp:scaled;
  end;

@ @<Glob...@>=
ci:charinfo_short;

@ We ought to give special care to the efficiency of one part of |hlist_out|,
since it belongs to \TeX's inner loop. When a |char_node| is encountered,
we save a little time by processing several nodes in succession until
reaching a non-|char_node|. The program uses the fact that |set_char_0=0|.
@^inner loop@>

@<Output node |p| for |hlist_out|...@>=
if is_char_node(p) then
  begin
  repeat
  if x_displace(p)<>0 then cur.h := cur.h + x_displace(p);
  if y_displace(p)<>0 then cur.v := cur.v - y_displace(p);
  synch_pos_with_cur; f:=font(p); c:=character(p);
  ci := char_info_short(f,c);
  if f<>dvi_f then @<Change font |dvi_f| to |f|@>;
  c_ht:=charinfo_height(ci);
  c_dp:=charinfo_depth(ci);
  c_wd:=charinfo_width(ci);
  if (font_natural_dir(f)<>-1) then begin
    case font_direction(dvi_direction) of
    dir__LT,dir__LB: begin
      dvi_set(c)(c_wd);
      end;
    dir__RT,dir__RB: begin
      dvi_put(c);
      end;
    dir__TL,dir__TR,dir__BL,dir__BR: begin
      c_wd := c_ht + c_dp;
      dvi_put(c);
      end;
    dir__LL: begin
      pos_right(c_wd);
      dvi_put(c);
      end;
    dir__RR: begin
      pos_left(c_wd);
      dvi_put(c);
      end;
    dir__LR: begin
      dvi_set(c)(c_wd);
      end;
    dir__RL: begin
      dvi_put(c);
      end;
    dir__TT: begin
      c_wd := c_ht + c_dp;
      pos_down(c_wd);
      dvi_put(c);
      end;
    dir__TB: begin
      c_wd := c_ht + c_dp;
      dvi_put(c);
      end;
    dir__BT: begin
      c_wd := c_ht + c_dp;
      dvi_put(c);
      end;
    dir__BB: begin
      c_wd := c_ht + c_dp;
      pos_up(c_wd);
      dvi_put(c);
      end;
    endcases;
  end else begin
    case font_direction(dvi_direction) of
    dir__LT: begin
      dvi_set(c)(c_wd);
      end;
    dir__LB: begin
      pos_down(c_ht);
      dvi_set(c)(c_wd);
      end;
    dir__RT: begin
      pos_left(c_wd);
      dvi_put(c);
      end;
    dir__RB: begin
      pos_down(c_ht);
      pos_left(c_wd);
      dvi_put(c);
      end;
    dir__TL: begin
      pos_down(c_ht);
      pos_left(c_wd);
      dvi_put(c);
      c_wd := c_ht + c_dp;
      end;
    dir__TR: begin
      pos_down(c_ht);
      dvi_put(c);
      c_wd := c_ht + c_dp;
      end;
    dir__BL: begin
      pos_left(c_wd);
      pos_up(c_dp);
      dvi_put(c);
      c_wd := c_ht + c_dp;
      end;
    dir__BR: begin
      pos_up(c_dp);
      dvi_put(c);
      c_wd := c_ht + c_dp;
      end;
    dir__LL,dir__LR: begin
      pos_down((c_ht - c_dp) div 2);
      dvi_set(c)(c_wd);
      end;
    dir__RL,dir__RR: begin
      pos_left(c_wd);
      pos_down((c_ht - c_dp) div 2);
      dvi_put(c);
      end;
    dir__TT,dir__TB: begin
      pos_down(c_ht);
      pos_left(c_wd div 2);
      dvi_put(c);
      c_wd:=c_ht + c_dp;
      end;
    dir__BT,dir__BB: begin
      pos_up(c_dp);
      pos_left(c_wd div 2);
      dvi_put(c);
      c_wd := c_ht + c_dp;
      end;
     endcases;
    end;
  if x_displace(p)<>0 then cur.h := cur.h - x_displace(p);
  if y_displace(p)<>0 then cur.v := cur.v + y_displace(p);
  cur.h:=cur.h+c_wd;
  p:=vlink(p);
  until not is_char_node(p);
  @<Record current point {\sl Sync\TeX} information@>;
  end
else @<Output the non-|char_node| |p| for |hlist_out|
    and move to the next node@>

@ @<Change font |dvi_f| to |f|@>=
begin if not font_used(f) then
  begin dvi_font_def(f); set_font_used(f,true);
  end;
oval:=f-font_base-1; ocmd:=fnt1; out_cmd;@/
dvi_f:=f;
end

@ @<Output the non-|char_node| |p| for |hlist_out|...@>=
begin case type(p) of
hlist_node_case,vlist_node_case:@<Output a box in an hlist@>;
rule_node_case: begin
  if not (dir_orthogonal(dir_primary[rule_dir(p)])(dir_primary[dvi_direction]))
    then begin
    rule_ht:=height(p); rule_dp:=depth(p); rule_wd:=width(p);
    end
  else begin
    rule_ht:=width(p) div 2;
    rule_dp:=width(p) div 2;
    rule_wd:=height(p)+depth(p);
    end;
  goto fin_rule;
  end;
whatsit_node_case: @<Output the whatsit node |p| in an hlist@>;
glue_node_case: @<Move right or output leaders@>;
disc_node_case: if vlink(no_break(p))<>null then if subtype(p)<>select_disc then begin
  vlink(tlink(no_break(p))):=vlink(p);
  q:=vlink(no_break(p));
  vlink(no_break(p)):=null;
  vlink(p):=q;
  end;
margin_kern_node_case:cur.h:=cur.h+width(p);
kern_node_case: begin
  @<Record |kern_node| {\sl Sync\TeX} information@>;
  cur.h:=cur.h+width(p);
end;
math_node_case: begin
  @<Record |math_node| {\sl Sync\TeX} information@>;
  cur.h:=cur.h+surround(p);
end;
othercases do_nothing
endcases;@/
goto next_p;
fin_rule: @<Output a rule in an hlist@>;
move_past: begin
  cur.h:=cur.h+rule_wd;
  @<Record horizontal |rule_node| or |glue_node| {\sl Sync\TeX} information@>;
end;
next_p:p:=vlink(p);
end

@ @<Output a box in an hlist@>=
begin
if not (dir_orthogonal(dir_primary[box_dir(p)])(dir_primary[dvi_direction]))
  then begin
  effective_horizontal:=width(p);
  basepoint_vertical:=0;
  if dir_opposite(dir_secondary[box_dir(p)])(dir_secondary[dvi_direction]) then
    basepoint_horizontal:=width(p)
  else
    basepoint_horizontal:=0;
  end
else begin
  effective_horizontal:=height(p)+depth(p);
  if not is_mirrored(box_dir(p)) then
    if dir_eq(dir_primary[box_dir(p)])(dir_secondary[dvi_direction]) then
      basepoint_horizontal:=height(p)
    else
      basepoint_horizontal:=depth(p)
  else
    if dir_eq(dir_primary[box_dir(p)])(dir_secondary[dvi_direction]) then
      basepoint_horizontal:=depth(p)
    else
      basepoint_horizontal:=height(p);
  if dir_eq(dir_secondary[box_dir(p)])(dir_primary[dvi_direction]) then
    basepoint_vertical:= -(width(p) div 2)
  else
    basepoint_vertical:= (width(p) div 2);
  end;
if not is_mirrored(dvi_direction) then
  basepoint_vertical := basepoint_vertical + shift_amount(p)
    {shift the box `down'}
else
  basepoint_vertical := basepoint_vertical - shift_amount(p);
    {shift the box `up'}
if list_ptr(p)=null then begin
  @<Record void list {\sl Sync\TeX} information@>;
  cur.h:=cur.h + effective_horizontal;
  end
else begin
  temp_ptr:=p; edge:=cur.h; cur.h:=cur.h + basepoint_horizontal;
  edge_v:=cur.v; cur.v:=base_line + basepoint_vertical;
  synch_dvi_with_cur; save_dvi:=dvi;
  save_box_pos:=box_pos;
  if type(p)=vlist_node then vlist_out@+else hlist_out;
  dvi:=save_dvi;
  box_pos:=save_box_pos;
  cur.h:=edge+effective_horizontal; cur.v:=base_line;
  end
end

@ @<Output a rule in an hlist@>=
if is_running(rule_ht) then rule_ht:=height(this_box);
if is_running(rule_dp) then rule_dp:=depth(this_box);
rule_ht:=rule_ht+rule_dp; {this is the rule thickness}
if (rule_ht>0)and(rule_wd>0) then {we don't output empty rules}
  begin cur.v:=base_line+rule_dp; synch_pos_with_cur;
  case box_direction(dvi_direction) of
  dir_TL_: begin
    dvi_set_rule(rule_ht)(rule_wd);
    end;
  dir_BL_: begin
    pos_down(rule_ht);
    dvi_set_rule(rule_ht)(rule_wd);
    end;
  dir_TR_: begin
    pos_left(rule_wd);
    dvi_put_rule(rule_ht)(rule_wd);
    end;
  dir_BR_: begin
    pos_left(rule_wd);
    pos_down(rule_ht);
    dvi_put_rule(rule_ht)(rule_wd);
    end;
  dir_LT_: begin
    pos_down(rule_wd);
    pos_left(rule_ht);
    dvi_set_rule(rule_wd)(rule_ht);
    end;
  dir_RT_: begin
    pos_down(rule_wd);
    dvi_put_rule(rule_wd)(rule_ht);
    end;
  dir_LB_: begin
    pos_left(rule_ht);
    dvi_set_rule(rule_wd)(rule_ht);
    end;
  dir_RB_: begin
    dvi_put_rule(rule_wd)(rule_ht);
    end;
  end;
  cur.v:=base_line;
  end

@ @d billion==float_constant(1000000000)
@d vet_glue(#)== glue_temp:=#;
  if glue_temp>billion then
           glue_temp:=billion
  else if glue_temp<-billion then
           glue_temp:=-billion

@<Move right or output leaders@>=
begin g:=glue_ptr(p); rule_wd:=width(g)-cur_g;
if g_sign<>normal then
  begin if g_sign=stretching then
    begin if stretch_order(g)=g_order then
      begin cur_glue:=cur_glue+stretch(g);
      vet_glue(float(glue_set(this_box))*cur_glue);
@^real multiplication@>
      cur_g:=round(glue_temp);
      end;
    end
  else if shrink_order(g)=g_order then
      begin cur_glue:=cur_glue-shrink(g);
      vet_glue(float(glue_set(this_box))*cur_glue);
      cur_g:=round(glue_temp);
      end;
  end;
rule_wd:=rule_wd+cur_g;

if subtype(p)>=a_leaders then
  @<Output leaders in an hlist, |goto fin_rule| if a rule
    or to |next_p| if done@>;
goto move_past;
end

@ @<Output leaders in an hlist...@>=
begin leader_box:=leader_ptr(p);
if type(leader_box)=rule_node then
  begin rule_ht:=height(leader_box); rule_dp:=depth(leader_box);
  goto fin_rule;
  end;
if not (dir_orthogonal(dir_primary[box_dir(leader_box)])(dir_primary[dvi_direction]))
  then leader_wd:=width(leader_box)
else
  leader_wd:=height(leader_box)+depth(leader_box);
if (leader_wd>0)and(rule_wd>0) then
  begin rule_wd:=rule_wd+10; {compensate for floating-point rounding}
  edge:=cur.h+rule_wd; lx:=0;
  @<Let |cur.h| be the position of the first box, and set |leader_wd+lx|
    to the spacing between corresponding parts of boxes@>;
  while cur.h+leader_wd<=edge do
    @<Output a leader box at |cur.h|,
      then advance |cur.h| by |leader_wd+lx|@>;
  cur.h:=edge-10; goto next_p;
  end;
end

@ The calculations related to leaders require a bit of care. First, in the
case of |a_leaders| (aligned leaders), we want to move |cur.h| to
|left_edge| plus the smallest multiple of |leader_wd| for which the result
is not less than the current value of |cur.h|; i.e., |cur.h| should become
$|left_edge|+|leader_wd|\times\lceil
(|cur.h|-|left_edge|)/|leader_wd|\rceil$.  The program here should work in
all cases even though some implementations of \PASCAL\ give nonstandard
results for the |div| operation when |cur.h| is less than |left_edge|.

In the case of |c_leaders| (centered leaders), we want to increase |cur.h|
by half of the excess space not occupied by the leaders; and in the
case of |x_leaders| (expanded leaders) we increase |cur.h|
by $1/(q+1)$ of this excess space, where $q$ is the number of times the
leader box will be replicated. Slight inaccuracies in the division might
accumulate; half of this rounding error is placed at each end of the leaders.

@<Let |cur.h| be the position of the first box, ...@>=
if subtype(p)=a_leaders then
  begin save_h:=cur.h;
  cur.h:=left_edge+leader_wd*((cur.h-left_edge)@!div leader_wd);
  if cur.h<save_h then cur.h:=cur.h+leader_wd;
  end
else  begin lq:=rule_wd div leader_wd; {the number of box copies}
  lr:=rule_wd mod leader_wd; {the remaining space}
  if subtype(p)=c_leaders then cur.h:=cur.h+(lr div 2)
  else  begin lx:=lr div (lq+1);
    cur.h:=cur.h+((lr-(lq-1)*lx) div 2);
    end;
  end

@ The `\\{synch}' operations here are intended to decrease the number of
bytes needed to specify horizontal and vertical motion in the \.{DVI} output.

@<Output a leader box at |cur.h|, ...@>=
begin
if not (dir_orthogonal(dir_primary[box_dir(leader_box)])(dir_primary[dvi_direction]))
  then begin
  basepoint_vertical:=0;
 if dir_opposite(dir_secondary[box_dir(leader_box)])(dir_secondary[dvi_direction]) then
    basepoint_horizontal:=width(leader_box)
  else
    basepoint_horizontal:=0;
  end
else begin
  if not is_mirrored(box_dir(leader_box)) then
    if dir_eq(dir_primary[box_dir(leader_box)])(dir_secondary[dvi_direction]) then
      basepoint_horizontal:=height(leader_box)
    else
      basepoint_horizontal:=depth(leader_box)
  else
    if dir_eq(dir_primary[box_dir(leader_box)])(dir_secondary[dvi_direction]) then
      basepoint_horizontal:=depth(leader_box)
    else
      basepoint_horizontal:=height(leader_box);
  if dir_eq(dir_secondary[box_dir(leader_box)])(dir_primary[dvi_direction]) then
    basepoint_vertical:= -(width(leader_box) div 2)
  else
    basepoint_vertical:= (width(leader_box) div 2);
  end;
if not is_mirrored(dvi_direction) then
  basepoint_vertical := basepoint_vertical + shift_amount(leader_box)
    {shift the box `down'}
else
  basepoint_vertical := basepoint_vertical - shift_amount(leader_box);
    {shift the box `up'}
temp_ptr:=leader_box;
edge_h:=cur.h; cur.h:=cur.h + basepoint_horizontal;
edge_v:=cur.v; cur.v:=base_line + basepoint_vertical;
synch_dvi_with_cur; save_dvi:=dvi;
save_box_pos:=box_pos;
outer_doing_leaders:=doing_leaders; doing_leaders:=true;
if type(leader_box)=vlist_node then vlist_out@+else hlist_out;
doing_leaders:=outer_doing_leaders;
box_pos:=save_box_pos;
dvi:=save_dvi;
cur.h:=edge_h+leader_wd+lx; cur.v:=base_line;
end

@ The |vlist_out| routine is similar to |hlist_out|, but a bit simpler.

@p procedure vlist_out; {output a |vlist_node| box}
label move_past, fin_rule, next_p;
var left_edge: scaled; {the left coordinate for this box}
@!top_edge: scaled; {the top coordinate for this box}
@!save_v: scaled; {what |cur.v| should pop to}
@!save_dvi: scaledpos; {what |dvi| should pop to}
@!save_box_pos: scaledpos; {what |box_pos| should pop to}
@!this_box: pointer; {pointer to containing box}
@!g_order: glue_ord; {applicable order of infinity for glue}
@!g_sign: normal..shrinking; {selects type of glue}
@!p:pointer; {current position in the vlist}
@!save_loc:integer; {\.{DVI} byte location upon entry}
@!leader_box:pointer; {the leader box being replicated}
@!leader_ht:scaled; {height of leader box being replicated}
@!lx:scaled; {extra space between leader boxes}
@!outer_doing_leaders:boolean; {were we doing leaders?}
@!edge:scaled; {bottom boundary of leader space}
@!glue_temp:real; {glue value before rounding}
@!cur_glue:real; {glue seen so far}
@!cur_g:scaled; {rounded equivalent of |cur_glue| times the glue ratio}
@!save_direction: integer;
@!effective_vertical: scaled;
@!basepoint_horizontal: scaled;
@!basepoint_vertical: scaled;
@!edge_v: scaled;
begin cur_g:=0; cur_glue:=float_constant(0);
this_box:=temp_ptr; g_order:=glue_order(this_box);
g_sign:=glue_sign(this_box); p:=list_ptr(this_box);
{pdfassert(p<>0);}
set_to_zero(cur); box_pos:=pos;
save_direction:=dvi_direction;
dvi_direction:=box_dir(this_box);
incr(cur_s);
if cur_s>0 then dvi_out(push);
if cur_s>max_push then max_push:=cur_s;
save_loc:=dvi_offset+dvi_ptr; left_edge:=cur.h;
@<Start vlist {\sl Sync\TeX} information record@>;
cur.v:=cur.v-height(this_box);
top_edge:=cur.v;
while p<>null do @<Output node |p| for |vlist_out| and move to the next node,
  maintaining the condition |cur.h=left_edge|@>;
@<Finish vlist {\sl Sync\TeX} information record@>;
prune_movements(save_loc);
if cur_s>0 then dvi_pop(save_loc);
decr(cur_s);
dvi_direction:=save_direction;
end;

@ @<Output node |p| for |vlist_out|...@>=
begin if is_char_node(p) then begin print_font_and_char(p); confusion("vlistout"); end
@:this can't happen vlistout}{\quad vlistout@>
else @<Output the non-|char_node| |p| for |vlist_out|@>;
next_p:p:=vlink(p);
end

@ @<Output the non-|char_node| |p| for |vlist_out|@>=
begin case type(p) of
hlist_node_case,vlist_node_case:@<Output a box in a vlist@>;
rule_node_case: begin
  if not (dir_orthogonal(dir_primary[rule_dir(p)])(dir_primary[dvi_direction]))
    then begin
    rule_ht:=height(p); rule_dp:=depth(p); rule_wd:=width(p);
    end
  else begin
    rule_ht:=width(p) div 2;
    rule_dp:=width(p) div 2;
    rule_wd:=height(p)+depth(p);
    end;
  goto fin_rule;
  end;
whatsit_node_case: @<Output the whatsit node |p| in a vlist@>;
glue_node_case: @<Move down or output leaders@>;
kern_node_case:cur.v:=cur.v+width(p);
othercases do_nothing
endcases;@/
goto next_p;
fin_rule: @<Output a rule in a vlist, |goto next_p|@>;
move_past: cur.v:=cur.v+rule_ht;
end

@ The |synch_v| here allows the \.{DVI} output to use one-byte commands
for adjusting |v| in most cases, since the baselineskip distance will
usually be constant.

@<Output a box in a vlist@>=
begin
if not (dir_orthogonal(dir_primary[box_dir(p)])(dir_primary[dvi_direction]))
  then begin
  effective_vertical:=height(p)+depth(p);
  if (type(p)=hlist_node) and is_mirrored(box_dir(p)) then
    basepoint_vertical:=depth(p)
  else
    basepoint_vertical:=height(p);
  if dir_opposite(dir_secondary[box_dir(p)])(dir_secondary[dvi_direction]) then
    basepoint_horizontal:=width(p)
  else
    basepoint_horizontal:=0;
  end
else begin
  effective_vertical:=width(p);
  if not is_mirrored(box_dir(p)) then
    if dir_eq(dir_primary[box_dir(p)])(dir_secondary[dvi_direction]) then
      basepoint_horizontal:=height(p)
    else
      basepoint_horizontal:=depth(p)
  else
    if dir_eq(dir_primary[box_dir(p)])(dir_secondary[dvi_direction]) then
      basepoint_horizontal:=depth(p)
    else
      basepoint_horizontal:=height(p);
  if dir_eq(dir_secondary[box_dir(p)])(dir_primary[dvi_direction]) then
    basepoint_vertical:=0
  else
    basepoint_vertical:=width(p);
  end;
basepoint_horizontal := basepoint_horizontal + shift_amount(p);
  {shift the box `right'}
if list_ptr(p)=null then begin
  cur.v:=cur.v+effective_vertical;
  @<Record void list {\sl Sync\TeX} information@>;
  end
else begin
  edge_v:=cur.v;
  cur.h:=left_edge + basepoint_horizontal;
  cur.v:=cur.v + basepoint_vertical;
  synch_dvi_with_cur; save_dvi:=dvi;
  save_box_pos:=box_pos;
  temp_ptr:=p;
  if type(p)=vlist_node then vlist_out@+else hlist_out;
  dvi:=save_dvi;
  box_pos:=save_box_pos;
  cur.h:=left_edge; cur.v:=edge_v + effective_vertical;
  end
end

@ @<Output a rule in a vlist...@>=
if is_running(rule_wd) then rule_wd:=width(this_box);
rule_ht:=rule_ht+rule_dp; {this is the rule thickness}
cur.v:=cur.v+rule_ht;
if (rule_ht>0)and(rule_wd>0) then {we don't output empty rules}
  begin synch_pos_with_cur;
  case box_direction(dvi_direction) of
  dir_TL_: begin
    dvi_put_rule(rule_ht)(rule_wd);
    end;
  dir_BL_: begin
    pos_down(rule_ht);
    dvi_put_rule(rule_ht)(rule_wd);
    end;
  dir_TR_: begin
    pos_left(rule_wd);
    dvi_set_rule(rule_ht)(rule_wd);
    end;
  dir_BR_: begin
    pos_down(rule_ht);
    pos_left(rule_wd);
    dvi_set_rule(rule_ht)(rule_wd);
    end;
  dir_LT_: begin
    pos_down(rule_wd);
    pos_left(rule_ht);
    dvi_set_rule(rule_wd)(rule_ht);
    end;
  dir_RT_: begin
    pos_down(rule_wd);
    dvi_put_rule(rule_wd)(rule_ht);
    end;
  dir_LB_: begin
    pos_left(rule_ht);
    dvi_set_rule(rule_wd)(rule_ht);
    end;
  dir_RB_: begin
    dvi_put_rule(rule_wd)(rule_ht);
    end;
  end;
  end;
goto next_p

@ @<Move down or output leaders@>=
begin g:=glue_ptr(p); rule_ht:=width(g)-cur_g;
if g_sign<>normal then
  begin if g_sign=stretching then
    begin if stretch_order(g)=g_order then
      begin cur_glue:=cur_glue+stretch(g);
      vet_glue(float(glue_set(this_box))*cur_glue);
@^real multiplication@>
      cur_g:=round(glue_temp);
      end;
    end
  else if shrink_order(g)=g_order then
      begin cur_glue:=cur_glue-shrink(g);
      vet_glue(float(glue_set(this_box))*cur_glue);
      cur_g:=round(glue_temp);
      end;
  end;
rule_ht:=rule_ht+cur_g;
if subtype(p)>=a_leaders then
  @<Output leaders in a vlist, |goto fin_rule| if a rule
    or to |next_p| if done@>;
goto move_past;
end

@ @<Output leaders in a vlist...@>=
begin leader_box:=leader_ptr(p);
if type(leader_box)=rule_node then
  begin rule_wd:=width(leader_box); rule_dp:=0;
  goto fin_rule;
  end;
if not (dir_orthogonal(dir_primary[box_dir(leader_box)])(dir_primary[dvi_direction]))
  then leader_ht:=height(leader_box)+depth(leader_box)
else
  leader_ht:=width(leader_box);
if (leader_ht>0)and(rule_ht>0) then
  begin rule_ht:=rule_ht+10; {compensate for floating-point rounding}
  edge:=cur.v+rule_ht; lx:=0;
  @<Let |cur.v| be the position of the first box, and set |leader_ht+lx|
    to the spacing between corresponding parts of boxes@>;
  while cur.v+leader_ht<=edge do
    @<Output a leader box at |cur.v|,
      then advance |cur.v| by |leader_ht+lx|@>;
  cur.v:=edge-10; goto next_p;
  end;
end

@ @<Let |cur.v| be the position of the first box, ...@>=
if subtype(p)=a_leaders then
  begin save_v:=cur.v;
  cur.v:=top_edge+leader_ht*((cur.v-top_edge)@!div leader_ht);
  if cur.v<save_v then cur.v:=cur.v+leader_ht;
  end
else  begin lq:=rule_ht div leader_ht; {the number of box copies}
  lr:=rule_ht mod leader_ht; {the remaining space}
  if subtype(p)=c_leaders then cur.v:=cur.v+(lr div 2)
  else  begin lx:=lr div (lq+1);
    cur.v:=cur.v+((lr-(lq-1)*lx) div 2);
    end;
  end

@ When we reach this part of the program, |cur.v| indicates the top of a
leader box, not its baseline.

@<Output a leader box at |cur.v|, ...@>=
begin
if not (dir_orthogonal(dir_primary[box_dir(leader_box)])(dir_primary[dvi_direction]))
  then begin
  effective_vertical:=height(leader_box)+depth(leader_box);
  if (type(leader_box)=hlist_node) and is_mirrored(box_dir(leader_box)) then
    basepoint_vertical:=depth(leader_box)
  else
    basepoint_vertical:=height(leader_box);
  if dir_opposite(dir_secondary[box_dir(leader_box)])(dir_secondary[dvi_direction]) then
    basepoint_horizontal:=width(leader_box)
  else
    basepoint_horizontal:=0;
  end
else begin
  effective_vertical:=width(leader_box);
  if not is_mirrored(box_dir(leader_box)) then
    if dir_eq(dir_primary[box_dir(leader_box)])(dir_secondary[dvi_direction]) then
      basepoint_horizontal:=height(leader_box)
    else
      basepoint_horizontal:=depth(leader_box)
  else
    if dir_eq(dir_primary[box_dir(leader_box)])(dir_secondary[dvi_direction]) then
      basepoint_horizontal:=depth(leader_box)
    else
      basepoint_horizontal:=height(leader_box);
  if dir_eq(dir_secondary[box_dir(leader_box)])(dir_primary[dvi_direction]) then
    basepoint_vertical:= width(leader_box)
  else
    basepoint_vertical:= 0;
  end;
basepoint_horizontal := basepoint_horizontal + shift_amount(leader_box);
  {shift the box `right'}
temp_ptr:=leader_box;
cur.h:=left_edge + basepoint_horizontal;
edge_v:=cur.v ;
cur.v:=cur.v + basepoint_vertical;
synch_dvi_with_cur; save_dvi:=dvi;
save_box_pos:=box_pos;
outer_doing_leaders:=doing_leaders; doing_leaders:=true;
if type(leader_box)=vlist_node then vlist_out@+else hlist_out;
doing_leaders:=outer_doing_leaders;
box_pos:=save_box_pos;
dvi:=save_dvi;
cur.h:=left_edge; cur.v:=edge_v+leader_ht+lx;
end

@ The |hlist_out| and |vlist_out| procedures are now complete, so we are
ready for the |dvi_ship_out| routine that gets them started in the first place.

@p procedure dvi_ship_out(@!p:pointer); {output the box |p|}
label done;
var page_loc:integer; {location of the current |bop|}
@!j,@!k:0..9; {indices to first ten count registers}
@!s:pool_pointer; {index into |str_pool|}
@!old_setting:0..max_selector; {saved |selector| setting}
pre_callback_id:integer;
post_callback_id:integer;
ret:boolean;
begin
@<Start sheet {\sl Sync\TeX} information record@>;
pre_callback_id:=callback_defined(start_page_number_callback);
post_callback_id:=callback_defined(stop_page_number_callback);
if (tracing_output>0)and(pre_callback_id=0) then
  begin print_nl(""); print_ln;
  print("Completed box being shipped out");
@.Completed box...@>
  end;
if pre_callback_id>0 then
  ret:=run_callback(pre_callback_id,'->')
else if pre_callback_id=0 then begin
  if term_offset>max_print_line-9 then print_ln
  else if (term_offset>0)or(file_offset>0) then print_char(" ");
  print_char("["); j:=9;
  while (count(j)=0)and(j>0) do decr(j);
  for k:=0 to j do
    begin print_int(count(k));
    if k<j then print_char(".");
    end;
  end;
update_terminal;
if (tracing_output>0)and(post_callback_id=0) then
  begin print_char("]");
  begin_diagnostic; show_box(p); end_diagnostic(true);
  end;
@<Ship box |p| out@>;
if (tracing_output<=0)and(post_callback_id=0) then
  print_char("]");
dead_cycles:=0;
update_terminal; {progress report}
@<Flush the box from memory, showing statistics if requested@>;
if post_callback_id>0 then
  ret:=run_callback(post_callback_id,'->');
@<Finish sheet {\sl Sync\TeX} information record@>;
end;

@ @<Flush the box from memory, showing statistics if requested@>=
@!stat if (tracing_stats>1)and(pre_callback_id=0) then
  begin print_nl("Memory usage before: ");
@.Memory usage...@>
  print_int(var_used); print_char("&");
  print_int(dyn_used); print_char(";");
  end;
tats@/
flush_node_list(p);
@!stat if (tracing_stats>1)and(post_callback_id=0) then
  begin print(" after: ");
  print_int(var_used); print_char("&");
  print_int(dyn_used); print_ln;
  end;
tats

@ @<Ship box |p| out@>=
if box_dir(p) <> page_direction then
  pdf_warning("\shipout", "\pagedir != \bodydir; \box255 may be placed wrongly on the page.", true, true);
@<Update the values of |max_h| and |max_v|; but if the page is too large,
  |goto done|@>;
@<Initialize variables as |ship_out| begins@>;
page_loc:=dvi_offset+dvi_ptr;
dvi_out(bop);
for k:=0 to 9 do dvi_four(count(k));
dvi_four(last_bop); last_bop:=page_loc;
{Think in upright page/paper coordinates): First preset |pos.h| and |pos.v| to the DVI origin.}
pos.h := one_true_inch;
pos.v := cur_page_size.v - one_true_inch;
box_pos := pos; dvi := pos;
{Then calculate |cur.h| and |cur.v| within the upright coordinate system
for the DVI origin depending on the |page_direction|.}
dvi_direction:=page_direction;
case box_direction(dvi_direction) of
dir_TL_,dir_LT_: begin
  cur.h := h_offset;
  cur.v := v_offset;
  end;
dir_TR_,dir_RT_: begin
  cur.h := cur_page_size.h - page_right_offset - one_true_inch;
  cur.v := v_offset;
  end;
dir_BL_,dir_LB_: begin
  cur.h := h_offset;
  cur.v := cur_page_size.v - page_bottom_offset - one_true_inch;
  end;
dir_RB_,dir_BR_: begin
  cur.h := cur_page_size.h - page_right_offset - one_true_inch;
  cur.v := cur_page_size.v - page_bottom_offset - one_true_inch;
  end;
end;
{The movement is actually done within the upright page coordinate system.}
dvi_direction := dir_TL_; {only temporarily for this adjustment}
synch_pos_with_cur; box_pos := pos; {keep track on page}
{Then switch to page box coordinate system; do |height(p)| movement.}
dvi_direction := page_direction;
cur.h := 0;
cur.v := height(p);
synch_pos_with_cur;
{Now we are at the point on the page where the origin of the page box should go.}
temp_ptr:=p;
if type(p)=vlist_node then vlist_out@+else hlist_out;
dvi_out(eop); incr(total_pages); cur_s:=-1;
done:

@ Sometimes the user will generate a huge page because other error messages
are being ignored. Such pages are not output to the \.{dvi} file, since they
may confuse the printing software.

@<Update the values of |max_h| and |max_v|; but if the page is too large...@>=
if (height(p)>max_dimen)or@|(depth(p)>max_dimen)or@|
   (height(p)+depth(p)+v_offset>max_dimen)or@|
   (width(p)+h_offset>max_dimen) then
  begin print_err("Huge page cannot be shipped out");
@.Huge page...@>
  help2("The page just created is more than 18 feet tall or")@/
   ("more than 18 feet wide, so I suspect something went wrong.");
  error;
  if tracing_output<=0 then
    begin begin_diagnostic;
    print_nl("The following box has been deleted:");
@.The following...deleted@>
    show_box(p);
    end_diagnostic(true);
    end;
  goto done;
  end;
if height(p)+depth(p)+v_offset>max_v then max_v:=height(p)+depth(p)+v_offset;
if width(p)+h_offset>max_h then max_h:=width(p)+h_offset

@ At the end of the program, we must finish things off by writing the
post\-amble. If |total_pages=0|, the \.{DVI} file was never opened.
If |total_pages>=65536|, the \.{DVI} file will lie. And if
|max_push>=65536|, the user deserves whatever chaos might ensue.

An integer variable |k| will be declared for use by this routine.

@<Finish the \.{DVI} file@>=
while cur_s>-1 do
  begin if cur_s>0 then dvi_out(pop)
  else  begin dvi_out(eop); incr(total_pages);
    end;
  decr(cur_s);
  end;
if total_pages=0 then begin
  if callback_id=0 then
    print_nl("No pages of output.")
  else if callback_id>0 then
    res:=run_callback(callback_id,'->');
  end
@.No pages of output@>
else  begin dvi_out(post); {beginning of the postamble}
  dvi_four(last_bop); last_bop:=dvi_offset+dvi_ptr-5; {|post| location}
  dvi_four(25400000); dvi_four(473628672); {conversion ratio for sp}
  prepare_mag; dvi_four(mag); {magnification factor}
  dvi_four(max_v); dvi_four(max_h);@/
  dvi_out(max_push div 256); dvi_out(max_push mod 256);@/
  dvi_out((total_pages div 256) mod 256); dvi_out(total_pages mod 256);@/
  @<Output the font definitions for all fonts that were used@>;
  dvi_out(post_post); dvi_four(last_bop); dvi_out(id_byte);@/
  k:=4+((dvi_buf_size-dvi_ptr) mod 4); {the number of 223's}
  while k>0 do
    begin dvi_out(223); decr(k);
    end;
  @<Empty the last bytes out of |dvi_buf|@>;
  if callback_id=0 then begin
    print_nl("Output written on "); slow_print(output_file_name);
@.Output written on x@>
    print(" ("); print_int(total_pages); print(" page");
    if total_pages<>1 then print_char("s");
    print(", "); print_int(dvi_offset+dvi_ptr); print(" bytes).");
    end
  else if callback_id>0 then
    res:=run_callback(callback_id,'->');
  b_close(dvi_file);
  end

@ @<Output the font definitions...@>=
k := max_font_id;
while k>0 do
  begin if font_used(k) then dvi_font_def(k);
  decr(k);
  end


@* \[32a] \pdfTeX\ basic.

Initialize \pdfTeX's parameters to some useful default value.
Helpful in case one forgets to set them during initex run.

@<Initialize table entries...@>=
pdf_h_origin := one_inch;
pdf_v_origin := one_inch;
pdf_compress_level := 9;
pdf_objcompresslevel := 0;
pdf_decimal_digits := 3;
pdf_image_resolution := 72;
pdf_minor_version := 4;
pdf_gamma := 1000;
pdf_image_gamma := 2200;
pdf_image_hicolor := 1;
pdf_image_apply_gamma := 0;
pdf_px_dimen := one_bp;
pdf_draftmode := 0;

@ The subroutines define the corresponding macros so we can use them
in C.

@d flushable(#) == (# = str_ptr - 1)

@d is_valid_char(#) == char_exists(f,#)

@p function get_pdf_compress_level: integer;
begin
    get_pdf_compress_level := pdf_compress_level;
end;

function get_nullfont: internal_font_number;
begin
    get_nullfont := null_font;
end;

function get_luatexversion: integer;
begin
    get_luatexversion := luatex_version;
end;

function get_luatexrevision: str_number;
begin
    get_luatexrevision := luatex_revision;
end;

function get_par_shape_ptr: halfword;
begin
    get_par_shape_ptr := par_shape_ptr;
end;

function get_escape_char: integer;
begin
    get_escape_char := escape_char;
end;

function get_undefined_control_sequence: integer;
begin
    get_undefined_control_sequence := undefined_control_sequence;
end;

function get_fontbase: internal_font_number;
begin
    get_fontbase := font_base;
end;

function get_nullcs: pointer;
begin
    get_nullcs := null_cs;
end;

function get_nullptr: pointer;
begin
    get_nullptr := null;
end;

function get_tex_int(code: integer): integer;
begin
    get_tex_int := int_par(code);
end;

function get_tex_dimen(code: integer): scaled;
begin
    get_tex_dimen := dimen_par(code);
end;


function get_x_height(f: internal_font_number): scaled;
begin
    get_x_height := x_height(f);
end;

function get_charwidth(f: internal_font_number; c: integer): scaled;
begin
    if is_valid_char(c) then
        get_charwidth := char_width(f,c)
    else
        get_charwidth := 0;
end;

function get_charheight(f: internal_font_number; c: integer): scaled;
begin
    if is_valid_char(c) then
        get_charheight := char_height(f,c)
    else
        get_charheight := 0;
end;

function get_chardepth(f: internal_font_number; c: integer): scaled;
begin
    if is_valid_char(c) then
        get_chardepth := char_depth(f,c)
    else
        get_chardepth := 0;
end;

function get_quad(f: internal_font_number): scaled;
begin
    get_quad := quad(f);
end;

function get_slant(f: internal_font_number): scaled;
begin
    get_slant := slant(f);
end;

function new_dummy_font: internal_font_number;
begin
    new_dummy_font := read_font_info(null_cs, "dummy", -1000, -1);
end;

function get_hash_size: integer;
begin
  get_hash_size:= hash_size;
end;

function get_eqtb_size: integer;
begin
  get_eqtb_size:= eqtb_size;
end;

function get_hash_base: integer;
begin
  get_hash_base:= hash_base;
end;

function get_font_id_base: integer;
begin
  get_font_id_base:= font_id_base;
end;


function get_cur_font: internal_font_number;
begin
  get_cur_font:= cur_font;
end;

procedure set_cur_font (f: internal_font_number);
var a:small_number;
begin
  a:=0;
  define(cur_font_loc,data,f);
end;

function get_current_name: str_number;
begin
  get_current_name:= name;
end;


@ Helper for debugging purposes

@p procedure short_display_n(@!p, m:integer); {prints highlights of list |p|}
var i: integer;
begin
i := 0;
font_in_short_display:=null_font;
if p = null then
    return;
while p<>null do
  begin if is_char_node(p) then
    begin if p<=max_halfword then
      begin if font(p)<>font_in_short_display then
        begin if not is_valid_font(font(p)) then
          print_char("*")
@.*\relax@>
        else print_font_identifier(font(p));
        print_char(" "); font_in_short_display:=font(p);
        end;
      print(qo(character(p)));
      end;
    end
  else begin
      if (type(p) = glue_node) or
         (type(p) = disc_node) or
         (type(p) = penalty_node) or
         ((type(p) = kern_node) and (subtype(p) = explicit)) then
         incr(i);
      if i >= m then
         return;
      if (type(p) = disc_node) then begin
          print("|");
          short_display(vlink(pre_break(p)));
          print("|");
          short_display(vlink(post_break(p)));
          print("|");
        end
        else
            @<Print a short indication of the contents of node |p|@>;
  end;
  p:=vlink(p);
  if p = null then
      return;
  end;
  update_terminal;
end;

@ Sometimes it is neccesary to allocate memory for PDF output that cannot
be deallocated then, so we use |pdf_mem| for this purpose.

@<Constants...@>=
@!inf_pdf_mem_size = 10000; {min size of the |pdf_mem| array}
@!sup_pdf_mem_size = 10000000; {max size of the |pdf_mem| array}

@ @<Glob...@>=
@!pdf_mem_size: integer;
@!pdf_mem: ^integer;
@!pdf_mem_ptr: integer;

@ @<Set init...@>=
pdf_mem_ptr := 1; {the first word is not used so we can use zero as a value for testing
whether a pointer to |pdf_mem| is valid}
pdf_mem_size := inf_pdf_mem_size; {allocated size of |pdf_mem| array}

@ We use |pdf_get_mem| to allocate memory in |pdf_mem|

@p function pdf_get_mem(s: integer): integer; {allocate |s| words in |pdf_mem|}
var a: integer;
begin
    if s > sup_pdf_mem_size - pdf_mem_ptr then
        overflow("PDF memory size (pdf_mem_size)", pdf_mem_size);
    if pdf_mem_ptr + s > pdf_mem_size then begin
        a := 0.2 * pdf_mem_size;
        if pdf_mem_ptr + s > pdf_mem_size + a then
            pdf_mem_size := pdf_mem_ptr + s
        else if pdf_mem_size < sup_pdf_mem_size - a then
            pdf_mem_size := pdf_mem_size + a
        else
            pdf_mem_size := sup_pdf_mem_size;
        pdf_mem := xreallocarray(pdf_mem, integer, pdf_mem_size);
    end;
    pdf_get_mem := pdf_mem_ptr;
    pdf_mem_ptr := pdf_mem_ptr + s;
end;

@* \[32b] \pdfTeX\ output low-level subroutines.
We use the similiar subroutines to handle the output buffer for
PDF output. When compress is used, the state of writing to buffer
is held in |zip_write_state|. We must write the header of PDF
output file in initialization to ensure that it will be the first
written bytes.

@<Constants...@>=
@!pdf_op_buf_size = 16384; {size of the PDF output buffer}
@!inf_pdf_os_buf_size = 1; {initial value of |pdf_os_buf_size|}
@!sup_pdf_os_buf_size = 5000000; {arbitrary upper hard limit of |pdf_os_buf_size|}
@!pdf_os_max_objs = 100; {maximum number of objects in object stream}

@ The following macros are similar as for \.{DVI} buffer handling

@d pdf_offset == (pdf_gone + pdf_ptr) {the file offset of last byte in PDF
buffer that |pdf_ptr| points to}

@d no_zip == 0 {no \.{ZIP} compression}
@d zip_writing == 1 {\.{ZIP} compression being used}
@d zip_finish == 2 {finish \.{ZIP} compression}

@d pdf_quick_out(#) == {output a byte to PDF buffer without checking of
overflow}
begin
    pdf_buf[pdf_ptr] := #;
    incr(pdf_ptr);
end

@d pdf_out(#) == {do the same as |pdf_quick_out| and flush the PDF
buffer if necessary}
begin
    pdf_room(1);
    pdf_quick_out(#);
end

@<Glob...@>=
@!pdf_file: byte_file; {the PDF output file}
@!pdf_buf: ^real_eight_bits; {pointer to the PDF output buffer or PDF object stream buffer}
@!pdf_buf_size: integer; {end of PDF output buffer or PDF object stream buffer}
@!pdf_ptr: longinteger; {pointer to the first unused byte in the PDF buffer or object stream buffer}
@!pdf_op_buf: ^real_eight_bits; {the PDF output buffer}
@!pdf_os_buf: ^real_eight_bits; {the PDF object stream buffer}
@!pdf_os_buf_size: integer; {current size of the PDF object stream buffer, grows dynamically}
@!pdf_os_objnum: ^integer; {array of object numbers within object stream}
@!pdf_os_objoff: ^integer; {array of object offsets within object stream}
@!pdf_os_objidx: pointer; {pointer into |pdf_os_objnum| and |pdf_os_objoff|}
@!pdf_os_cntr: integer; {counter for object stream objects}
@!pdf_op_ptr: integer; {store for PDF buffer |pdf_ptr| while inside object streams}
@!pdf_os_ptr: integer; {store for object stream |pdf_ptr| while outside object streams}
@!pdf_os_mode: boolean; {true if producing object stream}
@!pdf_os_enable: boolean; {true if object streams are globally enabled}
@!pdf_os_cur_objnum: integer; {number of current object stream object}
@!pdf_gone: longinteger; {number of bytes that were flushed to output}
@!pdf_save_offset: longinteger; {to save |pdf_offset|}
@!zip_write_state: integer; {which state of compression we are in}
@!fixed_pdf_minor_version: integer; {fixed minor part of the PDF version}
@!fixed_pdf_minor_version_set: boolean; {flag if the PDF version has been set}
@!fixed_pdf_objcompresslevel: integer; {fixed level for activating PDF object streams}
@!fixed_pdfoutput: integer; {fixed output format}
@!fixed_pdfoutput_set: boolean; {|fixed_pdfoutput| has been set?}
@!fixed_gamma: integer;
@!fixed_image_gamma: integer;
@!fixed_image_hicolor: boolean;
@!fixed_image_apply_gamma: integer;
@!fixed_pdf_draftmode: integer; {fixed \\pdfdraftmode}
@!pdf_page_group_val: integer;
@!epochseconds: integer;
@!microseconds: integer;
@!page_divert_val: integer;

@ @<Set init...@>=
pdf_gone := 0;
pdf_os_mode := false;
pdf_ptr := 0;
pdf_op_ptr := 0;
pdf_os_ptr := 0;
pdf_os_cur_objnum := 0;
pdf_os_cntr := 0;
pdf_buf_size := pdf_op_buf_size;
pdf_os_buf_size := inf_pdf_os_buf_size;
pdf_buf := pdf_op_buf;
pdf_seek_write_length := false;
zip_write_state := no_zip;
fixed_pdf_minor_version_set := false;
fixed_pdfoutput_set := false;
pdf_page_group_val := -1;
page_divert_val := 0;

@ @p
function fix_int(val, min, max: integer): integer;
begin
    if val < min then
        fix_int := min
    else if val > max then
        fix_int := max
    else
        fix_int := val;
end;

@ This ensures that |pdfminorversion| is set only before any bytes have
been written to the generated \.{PDF} file. Here also all variables for
\.{PDF} output are initialized, the \.{PDF} file is opened by |ensure_pdf_open|,
and the \.{PDF} header is written.

@p procedure check_pdfminorversion;
begin
    fix_pdfoutput;
    pdfassert(fixed_pdfoutput > 0);
    if not fixed_pdf_minor_version_set then begin
        fixed_pdf_minor_version_set := true;
        @<Initialize variables for \.{PDF} output@>;
        @<Write \.{PDF} header@>;
    end
    else begin
        @<Check that variables for \.{PDF} output are unchanged@>;
    end;
    if fixed_pdf_draftmode <> 0 then begin
        pdf_compress_level := 0; {re-fix it, might have been changed inbetween}
        fixed_pdf_objcompresslevel := 0;
    end;
end;

@ @<Initialize variables for \.{PDF} output@>=
prepare_mag;
if (pdf_minor_version < 0) or (pdf_minor_version > 9) then begin
    print_err("LuaTeX error (illegal pdfminorversion)");
    print_ln;
    help2 ("The pdfminorversion must be between 0 and 9.")@/
        ("I changed this to 4.");
    int_error (pdf_minor_version);
    pdf_minor_version := 4;
end;
fixed_pdf_minor_version := pdf_minor_version;
fixed_decimal_digits    := fix_int(pdf_decimal_digits, 0, 4);
fixed_gamma             := fix_int(pdf_gamma, 0, 1000000);
fixed_image_gamma       := fix_int(pdf_image_gamma, 0, 1000000);
fixed_image_hicolor     := fix_int(pdf_image_hicolor, 0, 1);
fixed_image_apply_gamma := fix_int(pdf_image_apply_gamma, 0, 1);
fixed_pdf_objcompresslevel := fix_int(pdf_objcompresslevel, 0, 3);
fixed_pdf_draftmode     := fix_int(pdf_draftmode, 0, 1);
fixed_inclusion_copy_font:= fix_int(pdf_inclusion_copy_font, 0, 1);
fixed_replace_font      := fix_int(pdf_replace_font, 0, 1);
fixed_pk_resolution     := fix_int(pdf_pk_resolution, 72, 8000);
if (fixed_pdf_minor_version >= 5) and (fixed_pdf_objcompresslevel > 0) then
    pdf_os_enable := true
else begin
    if fixed_pdf_objcompresslevel > 0 then begin
        pdf_warning("Object streams",
                    "\pdfobjcompresslevel > 0 requires \pdfminorversion > 4. Object streams disabled now.", true, true);
        fixed_pdf_objcompresslevel := 0;
    end;
    pdf_os_enable := false;
end;
if pdf_pk_resolution = 0 then {if not set from format file or by user}
    pdf_pk_resolution := pk_dpi; {take it from \.{texmf.cnf}}
pk_scale_factor :=
    divide_scaled(72, fixed_pk_resolution, 5 + fixed_decimal_digits);
if not callback_defined(read_pk_file_callback) then begin
    if pdf_pk_mode <> null then begin
        kpseinitprog('PDFTEX', fixed_pk_resolution,
                     makecstring(tokens_to_string(pdf_pk_mode)), nil);
        flush_string;
    end else
        kpseinitprog('PDFTEX', fixed_pk_resolution, nil, nil);
    if not kpsevarvalue('MKTEXPK') then
         kpsesetprogramenabled (kpsepkformat, 1, kpsesrccmdline);
    end;
set_job_id(year, month, day, time);
if (pdf_unique_resname > 0) and (pdf_resname_prefix = 0) then
    pdf_resname_prefix := get_resname_prefix

@ @<Check that variables for \.{PDF} output are unchanged@>=
if fixed_pdf_minor_version <> pdf_minor_version then
    pdf_error("setup",
              "\pdfminorversion cannot be changed after data is written to the PDF file");
if fixed_pdf_draftmode <> pdf_draftmode then
    pdf_error("setup",
              "\pdfdraftmode cannot be changed after data is written to the PDF file");

@ @<Write \.{PDF} header@>=
ensure_pdf_open;
pdf_print("%PDF-1.");
pdf_print_int_ln(fixed_pdf_minor_version);
pdf_print("%");
pdf_out(208); {'P' + 128}
pdf_out(212); {'T' + 128}
pdf_out(197); {'E' + 128}
pdf_out(216); {'X' + 128}
pdf_print_nl;

@ Checks that we have a name for the generated PDF file and that it's open.

@p procedure ensure_pdf_open;
begin
    if output_file_name <> 0 then
        return;
    if job_name = 0 then
        open_log_file;
    pack_job_name('.pdf');
    if fixed_pdf_draftmode = 0 then
        while not lua_b_open_out(pdf_file) do
            prompt_file_name('file name for output','.pdf');
    pdf_file:=name_file_pointer;
    output_file_name := b_make_name_string(pdf_file);
end;

@ The PDF buffer is flushed by calling |pdf_flush|, which checks the
variable |zip_write_state| and will compress the buffer before flushing if
neccesary. We call |pdf_begin_stream| to begin a stream  and |pdf_end_stream|
to finish it. The stream contents will be compressed if compression is turn on.

@p procedure pdf_flush; {flush out the |pdf_buf|}
var saved_pdf_gone : longinteger;
begin
    if not pdf_os_mode then begin
        saved_pdf_gone := pdf_gone;
        case zip_write_state of
            no_zip: if pdf_ptr > 0 then begin
                if fixed_pdf_draftmode = 0 then write_pdf(0, pdf_ptr - 1);
                pdf_gone := pdf_gone + pdf_ptr;
                pdf_last_byte := pdf_buf[pdf_ptr - 1];
            end;
            zip_writing:
                if fixed_pdf_draftmode = 0 then write_zip(false);
            zip_finish: begin
                if fixed_pdf_draftmode = 0 then write_zip(true);
                zip_write_state := no_zip;
            end;
        end;
        pdf_ptr := 0;
        if saved_pdf_gone > pdf_gone then
            pdf_error("file size", "File size exceeds architectural limits (pdf_gone wraps around)");
    end;
end;

procedure pdf_begin_stream; {begin a stream}
begin
    pdf_print_ln("/Length           ");
    pdf_seek_write_length := true; {fill in length at |pdf_end_stream| call}
    pdf_stream_length_offset := pdf_offset - 11;
    pdf_stream_length := 0;
    pdf_last_byte := 0;
    if pdf_compress_level > 0 then begin
        pdf_print_ln("/Filter /FlateDecode");
        pdf_print_ln(">>");
        pdf_print_ln("stream");
        pdf_flush;
        zip_write_state := zip_writing;
    end
    else begin
        pdf_print_ln(">>");
        pdf_print_ln("stream");
        pdf_save_offset := pdf_offset;
    end;
end;

procedure pdf_end_stream; {end a stream}
begin
    if zip_write_state = zip_writing then
        zip_write_state := zip_finish
    else
        pdf_stream_length := pdf_offset - pdf_save_offset;
    pdf_flush;
    if pdf_seek_write_length then
        write_stream_length(pdf_stream_length, pdf_stream_length_offset);
    pdf_seek_write_length := false;
    if pdf_last_byte <> pdf_new_line_char then
        pdf_out(pdf_new_line_char);
    pdf_print_ln("endstream");
    pdf_end_obj;
end;

@ Basic printing procedures for PDF output are very similiar to \TeX\ basic
printing ones but the output is going to PDF buffer. Subroutines with
suffix |_ln| append a new-line character to the PDF output.

@d pdf_new_line_char == 10 {new-line character for UNIX platforms}

@d pdf_print_nl == {output a new-line character to PDF buffer}
pdf_out(pdf_new_line_char)

@d pdf_print_ln(#) == {print out a string to PDF buffer followed by
a new-line character}
begin
    pdf_print(#);
    pdf_print_nl;
end

@d pdf_print_int_ln(#) == {print out an integer to PDF buffer followed by
a new-line character}
begin
    pdf_print_int(#);
    pdf_print_nl;
end

@<Declare procedures that need to be declared forward for \pdfTeX@>=
procedure pdf_error(t, p: str_number);
begin
    normalize_selector;
    print_err("LuaTeX error");
    if t <> 0 then begin
        print(" (");
        print(t);
        print(")");
    end;
    print(": "); print(p);
    succumb;
end;

procedure pdf_warning(t, p: str_number; prepend_nl, append_nl: boolean);
begin
    if interaction = error_stop_mode then
        wake_up_terminal;
    if prepend_nl then
        print_ln;
    print("LuaTeX warning");
    if t <> 0 then begin
        print(" (");
        print(t);
        print(")");
    end;
    print(": "); print(p);
    if append_nl then
        print_ln;
    if history=spotless then history:=warning_issued;
end;

procedure pdf_os_get_os_buf(s: integer); {check that |s| bytes more
fit into |pdf_os_buf|; increase it if required}
var a: integer;
begin
    if s > sup_pdf_os_buf_size - pdf_ptr then
        overflow("PDF object stream buffer", pdf_os_buf_size);
    if pdf_ptr + s > pdf_os_buf_size then begin
        a := 0.2 * pdf_os_buf_size;
        if pdf_ptr + s > pdf_os_buf_size + a then
            pdf_os_buf_size := pdf_ptr + s
        else if pdf_os_buf_size < sup_pdf_os_buf_size - a then
            pdf_os_buf_size := pdf_os_buf_size + a
        else
            pdf_os_buf_size := sup_pdf_os_buf_size;
        pdf_os_buf := xreallocarray(pdf_os_buf, real_eight_bits, pdf_os_buf_size);
        pdf_buf := pdf_os_buf;
        pdf_buf_size := pdf_os_buf_size;
    end;
end;

procedure pdf_room(n: integer); {make sure that there are at least |n| bytes free in PDF buffer}
begin
    if pdf_os_mode and (n + pdf_ptr > pdf_buf_size) then
        pdf_os_get_os_buf(n)
    else if not pdf_os_mode and (n > pdf_buf_size) then
        overflow("PDF output buffer", pdf_op_buf_size)
    else if not pdf_os_mode and (n + pdf_ptr > pdf_buf_size) then
        pdf_flush;
end;

procedure remove_last_space;
begin
    if (pdf_ptr > 0) and (pdf_buf[pdf_ptr - 1] = 32) then
        decr(pdf_ptr);
end;

function str_in_str(s, r: str_number; i: integer): boolean;
  {test equality of strings}
label not_found; {loop exit}
var j, k: pool_pointer; {running indices}
begin
    str_in_str := false;
    if length(s) < i + length(r) then
        return;
    j := i + str_start_macro(s);
    k := str_start_macro(r);
    while (j < str_start_macro(s + 1)) and (k < str_start_macro(r + 1)) do begin
        if str_pool[j] <> str_pool[k] then
            return;
        incr(j);
        incr(k);
    end;
    str_in_str := true;
end;

function tokens_to_string(p: pointer): str_number; {return a string from tokens
list}
var old_setting:integer;
begin
    if selector = new_string then
        pdf_error("tokens", "tokens_to_string() called while selector = new_string");
    old_setting:=selector; selector:=new_string;
    show_token_list(link(p),null,pool_size-pool_ptr);
    selector:=old_setting;
    last_tokens_string := make_string;
    tokens_to_string := last_tokens_string;
end;


@ To print |scaled| value to PDF output we need some subroutines to ensure
accurary.

@d max_integer == @"7FFFFFFF {$2^{31}-1$}
@d call_func(#) == begin if # <> 0 then do_nothing end


@<Glob...@>=
@!one_hundred_inch: scaled; {scaled value corresponds to 100in}
@!one_inch: scaled; {scaled value corresponds to 1in (rounded!)}
@!one_true_inch: scaled; {scaled value corresponds to 1truein (rounded!)}
@!one_hundred_bp: scaled; {scaled value corresponds to 100bp}
@!one_bp: scaled; {scaled value corresponds to 1bp (rounded!)}
@!ten_pow: array[0..9] of integer; {$10^0..10^9$}

@ @<Set init...@>=
one_hundred_inch := 7227 * 65536; {exact, 473628672}
one_inch := (one_hundred_inch + 50) div 100; {rounded to 4736287}
one_true_inch := one_inch;
one_hundred_bp := one_hundred_inch div 72; {exact, 6578176}
one_bp := (one_hundred_bp + 50) div 100; {rounded to 65782}
ten_pow[0] := 1;
for i := 1 to 9 do
    ten_pow[i] := 10*ten_pow[i - 1];

@ The function |divide_scaled| divides |s| by |m| using |dd| decimal
digits of precision. It is defined in C because it is a good candidate
for optimizations that are not possible in pascal.

@<Declare procedures that need to be declared forward for \pdfTeX@>=
function round_xn_over_d(@!x:scaled; @!n,@!d:integer):scaled;
var positive:boolean; {was |x>=0|?}
@!t,@!u,@!v:nonnegative_integer; {intermediate quantities}
begin if x>=0 then positive:=true
else  begin negate(x); positive:=false;
  end;
t:=(x mod @'100000)*n;
u:=(x div @'100000)*n+(t div @'100000);
v:=(u mod d)*@'100000 + (t mod @'100000);
if u div d>=@'100000 then arith_error:=true
else u:=@'100000*(u div d) + (v div d);
v := v mod d;
if 2*v >= d then
    incr(u);
if positive then
    round_xn_over_d := u
else
    round_xn_over_d := -u;
end;

@ @p
procedure pdf_print_bp(s: scaled); {print scaled as |bp|}
begin
    pdf_print_real(divide_scaled(s, one_hundred_bp, fixed_decimal_digits + 2),
                   fixed_decimal_digits);
end;

procedure pdf_print_mag_bp(s: scaled); {take |mag| into account}
begin
    prepare_mag;
    if mag <> 1000 then
        s := round_xn_over_d(s, mag, 1000);
    pdf_print_bp(s);
end;

@* \[32c] PDF page description.

@<Glob...@>=
@!fixed_pk_resolution: integer;
@!fixed_decimal_digits: integer;
@!fixed_gen_tounicode: integer;
@!fixed_inclusion_copy_font: integer;
@!fixed_replace_font: integer;
@!pk_scale_factor: integer;
@!pdf_output_option: integer;
@!pdf_output_value: integer;
@!pdf_draftmode_option: integer;
@!pdf_draftmode_value: integer;

@ @p
procedure pdf_use_font(f: internal_font_number; fontnum: integer);
{mark |f| as a used font; set |font_used(f)|, |pdf_font_size(f)| and |pdf_font_num(f)|}
begin
    set_pdf_font_size(f,font_size(f));
    set_font_used(f,true);
    pdfassert((fontnum > 0) or ((fontnum < 0) and (pdf_font_num(-fontnum) > 0)));
    set_pdf_font_num(f,fontnum);
    if pdf_move_chars > 0 then begin
        pdf_warning(0,"Primitive \pdfmovechars is obsolete.",true, true);
        pdf_move_chars := 0; {warn only once}
    end;
end;

@ To set PDF font we need to find out fonts with the same name, because \TeX\
can load the same font several times for various sizes. For such fonts we
define only one font resource. The array |pdf_font_num| holds the object
number of font resource. A negative value of an entry of |pdf_font_num|
indicates that the corresponding font shares the font resource with the font

@d pdf_print_resname_prefix ==
if pdf_resname_prefix <> 0 then
    pdf_print(pdf_resname_prefix)

@p procedure pdf_init_font(f: internal_font_number);
{create a font object}
var k, b: internal_font_number;
    i: integer;
begin
    pdfassert(not font_used(f));

    {if |f| is auto expanded then ensure the base font is initialized}
    if pdf_font_auto_expand(f) and (pdf_font_blink(f) <> null_font) then begin
        b := pdf_font_blink(f);
            {TODO: reinstate this check. disabled because wide fonts font have fmentries}
        if false and (not hasfmentry(b)) then
            pdf_error("font expansion", "auto expansion is only possible with scalable fonts");
        if not font_used(b) then
            pdf_init_font(b);
        set_font_map(f,font_map(b));
    end;

    {check whether |f| can share the font object with some |k|: we have 2 cases
    here: 1) |f| and |k| have the same tfm name (so they have been loaded at
    different sizes, eg 'cmr10' and 'cmr10 at 11pt'); 2) |f| has been auto
    expanded from |k|}
    if hasfmentry(f) or true then begin
        i := head_tab[obj_type_font];
        while i <> 0 do begin
            k := obj_info(i);
            if font_shareable(f,k) then
            begin
                pdfassert(pdf_font_num(k) <> 0);
                if pdf_font_num(k) < 0 then
                    pdf_use_font(f, pdf_font_num(k))
                else
                    pdf_use_font(f, -k);
                return;
            end;
            i := obj_link(i);
        end;
    end;

    {create a new font object for |f|}
    pdf_create_obj(obj_type_font, f);
    pdf_use_font(f, obj_ptr);
end;

procedure pdf_init_font_cur_val;
begin
    pdf_init_font(cur_val);
end;

function pdf_set_font(f: internal_font_number): internal_font_number;
{set the actual font on PDF page}
label found, found1;
var p: pointer;
    k: internal_font_number;
begin
    if not font_used(f) then
        pdf_init_font(f);
    set_ff(f); {set |ff| to the tfm number of the font sharing the font object
                with |f|; |ff| is either |f| or some font with the same tfm name
                at different size and/or expansion}
    k := ff;
    p := pdf_font_list;
    while p <> null do begin
        set_ff(info(p));
        if ff = k then
            goto found;
        p := link(p);
    end;
    pdf_append_list(f)(pdf_font_list); {|f| not found in |pdf_font_list|, append it now}
found:
    pdf_set_font := k;
end;

@ @p
procedure literal(s: str_number; literal_mode: integer; warn: boolean);
var j: pool_pointer; {current character code position}
begin
    if s>string_offset then begin { needed for |out_save| }
      j:=str_start_macro(s);
      if literal_mode = scan_special then begin
        if not (str_in_str(s, "PDF:", 0) or str_in_str(s, "pdf:", 0)) then begin
            if warn and not (str_in_str(s, "SRC:", 0)
                or str_in_str(s, "src:", 0)
                or (length(s) = 0)) then
                    print_nl("Non-PDF special ignored!");
            return;
        end;
        j := j + length("PDF:");
        if str_in_str(s, "direct:", length("PDF:")) then begin
            j := j + length("direct:");
            literal_mode := direct_always; end
        else if str_in_str(s, "page:", length("PDF:")) then begin
            j := j + length("page:");
            literal_mode := direct_page; end
        else
            literal_mode := set_origin;
      end;
    end;
    case literal_mode of
    set_origin: begin
        pdf_goto_pagemode;
        synch_pos_with_cur;
        pdf_set_pos(pos.h, pos.v);
        end;
    direct_page:
        pdf_goto_pagemode;
    direct_always:
        pdf_end_string_nl;
    othercases confusion("literal1")
    endcases;
    if s>string_offset then
      while j<str_start_macro(s+1) do begin
       pdf_out(str_pool[j]);
       incr(j);
      end
    else
      pdf_out(s);
    pdf_print_nl;
end;

procedure latelua(s: pointer; r: pointer);
var b: pool_pointer; {current character code position}
begin
    b := pool_ptr;
    luacall(s,r);
    if b<pool_ptr then begin
      pdf_goto_pagemode;
      while b<pool_ptr do begin
         pdf_out(str_pool[b]);
         incr(b);
      end;
      pdf_print_nl;
    end;
end;

@* \[32d] The cross-reference table.

The cross-reference table |obj_tab| is an array of |obj_tab_size| of
|obj_entry|. Each entry contains five integer fields and represents an object
in PDF file whose object number is the index of this entry in |obj_tab|.
Objects in |obj_tab| maybe linked into list; objects in such a linked list have
the same type.

@<Types...@>=
@!obj_entry = record@;@/
    int0, int1: integer;
    int2: longinteger;
    int3, int4: integer;
end;

@ The first field contains information representing identifier of this object.
It is usally a number for most of object types, but it may be a string number
for named destination or named thread.

The second field of |obj_entry| contains link to the next
object in |obj_tab| if this object is linked in a list.

The third field holds the byte offset of the object in the output PDF file,
or its byte offset within an object stream. As long as the object is not
written, this field is used for flags about the write status of the object;
then it has a negative value.

The fourth field holds the object number of the object stream, into which
the object is included.

The last field usually represents the pointer to some auxiliary data
structure depending on the object type; however it may be used as a counter as
well.

@d obj_info(#) == obj_tab[#].int0 {information representing identifier of this object}
@d obj_link(#) == obj_tab[#].int1 {link to the next entry in linked list}
@d obj_offset(#) == obj_tab[#].int2 {negative (flags), or byte offset for this object in PDF output file, or object stream number for this object}
@d obj_os_idx(#) == obj_tab[#].int3 {index of this object in object stream}
@d obj_aux(#) == obj_tab[#].int4 {auxiliary pointer}

@d set_obj_fresh(#) == obj_offset(#) := -2
@d set_obj_scheduled(#) == if intcast(obj_offset(#)) = -2 then obj_offset(#) := -1
@d is_obj_scheduled(#) == (intcast(obj_offset(#)) > -2)
@d is_obj_written(#) == (intcast(obj_offset(#)) > -1)

@# {types of objects}
@d obj_type_others              == 0 {objects which are not linked in any list}
@d obj_type_page                == 1 {index of linked list of Page objects}
@d obj_type_font                == 2 {index of linked list of Fonts objects}
@d obj_type_outline             == 3 {index of linked list of outline objects}
@d obj_type_dest                == 4 {index of linked list of destination objects}
@d obj_type_obj                 == 5 {index of linked list of raw objects}
@d obj_type_xform               == 6 {index of linked list of XObject forms}
@d obj_type_ximage              == 7 {index of linked list of XObject image}
@d obj_type_thread              == 8 {index of linked list of num article threads}
@d head_tab_max                 == obj_type_thread {max index of |head_tab|}

@# {max number of kids for balanced trees}
@d name_tree_kids_max      == 6 {max number of kids of node of name tree for
name destinations}

@# {when a whatsit node representing annotation is created, words |1..3| are
width, height and depth of this annotation; after shipping out words |1..4|
are rectangle specification of annotation. For whatsit node representing
destination |pdf_ann_left| and |pdf_ann_top| are used for some types of destinations}

@# {coordinates of destinations/threads/annotations (in whatsit node)}
@d pdf_ann_left(#)         == vmem(# + 2).sc
@d pdf_ann_top(#)          == vmem(# + 3).sc
@d pdf_ann_right(#)        == vmem(# + 4).sc
@d pdf_ann_bottom(#)       == vmem(# + 5).sc

@# {dimension of destinations/threads/annotations (in whatsit node)}
@d pdf_width(#)            == vmem(# + 2).sc
@d pdf_height(#)           == vmem(# + 3).sc
@d pdf_depth(#)            == vmem(# + 4).sc

@# {data structure for \.{\\pdfliteral}}
@d pdf_literal_data(#)     == vlink(#+2) {data}
@d pdf_literal_mode(#)     == type(#+2) {mode of resetting the text matrix
                              while writing data to the page stream}
@d pdf_literal_type(#)     == subtype(#+2) {indicates whether data is a |str_number| or
                               something else}
@# {modes of setting the current transformation matrix (CTM)}
@d set_origin              == 0 {end text (ET) if needed, set CTM to current point}
@d direct_page             == 1 {end text (ET) if needed, but don't change the CTM}
@d direct_always           == 2 {don't end text, don't change the CTM}
@d scan_special            == 3 {look into special text}

@# {data structure for \.{\\pdfcolorstack}}
@d pdf_colorstack_stack(#)  == vlink(#+2) {stack number}
@d pdf_colorstack_cmd(#)    == vinfo(#+2) {command: set, push, pop, current}
@d pdf_colorstack_data(#)   == vlink(#+3) {data}

@# {color stack commands}
@d colorstack_set          == 0
@d colorstack_push         == 1
@d colorstack_data         == 1 { last value where data field is set }
@d colorstack_pop          == 2
@d colorstack_current      == 3

@# {data structure for \.{\\pdfsetmatrix}}
@d pdf_setmatrix_data(#)   == vlink(#+2) {data}

@# {data structure for \.{\\pdfsave}}

@# {data structure for \.{\\pdfrestore}}

@# {data structure for \.{\\latelua}}
@d late_lua_data           == write_tokens {data}
@d late_lua_name(#)        == vlink(#+3) {name}

@# {data structure for \.{\\pdfobj} and \.{\\pdfrefobj}}
@d pdf_obj_objnum(#)       == vinfo(# + 2) {number of the raw object}
@d obj_data_ptr            == obj_aux {pointer to |pdf_mem|}
@d pdfmem_obj_size         == 4 {size of memory in |pdf_mem| which |obj_data_ptr| holds}
@d obj_obj_data(#)         == pdf_mem[obj_data_ptr(#) + 0] {object data}
@d obj_obj_is_stream(#)    == pdf_mem[obj_data_ptr(#) + 1] {will this object
                              be written as a stream instead of a dictionary?}
@d obj_obj_stream_attr(#)  == pdf_mem[obj_data_ptr(#) + 2] {additional
                              object attributes for streams}
@d obj_obj_is_file(#)      == pdf_mem[obj_data_ptr(#) + 3] {data should be
                              read from an external file?}

@# {data structure for \.{\\pdfxform} and \.{\\pdfrefxform}}
@d pdfmem_xform_size       == 6 {size of memory in |pdf_mem| which
                              |obj_data_ptr| holds}

@d pdf_xform_objnum(#)     == vinfo(# + 4) {object number}
@d obj_xform_width(#)      == pdf_mem[obj_data_ptr(#) + 0]
@d obj_xform_height(#)     == pdf_mem[obj_data_ptr(#) + 1]
@d obj_xform_depth(#)      == pdf_mem[obj_data_ptr(#) + 2]
@d obj_xform_box(#)        == pdf_mem[obj_data_ptr(#) + 3] {this field holds
                              pointer to the corresponding box}
@d obj_xform_attr(#)       == pdf_mem[obj_data_ptr(#) + 4] {additional xform
                              attributes}
@d obj_xform_resources(#)  == pdf_mem[obj_data_ptr(#) + 5] {additional xform
                              Resources}

@# {data structure for \.{\\pdfximage} and \.{\\pdfrefximage}}
@d pdf_ximage_idx(#)       == vinfo(# + 5) {image index in array}

@# {data structure of annotations; words 1..4 represent the coordinates of
    the annotation}
@d obj_annot_ptr           == obj_aux {pointer to corresponding whatsit node}
@d pdf_annot_data(#)       == vinfo(# + 6) {raw data of general annotations}
@d pdf_link_attr(#)        == vinfo(# + 6) {attributes of link annotations}
@d pdf_link_action(#)      == vlink(# + 6) {pointer to action structure}
@d pdf_annot_objnum(#)     == vmem(# + 7).int {object number of corresponding object}
@d pdf_link_objnum(#)      == vmem(# + 7).int {object number of corresponding object}

@# {types of actions}
@d pdf_action_page         == 0 {GoTo action}
@d pdf_action_goto         == 1 {GoTo action}
@d pdf_action_thread       == 2 {Thread action}
@d pdf_action_user         == 3 {user-defined action}

@# {data structure of actions}
@d pdf_action_type(#)      == type(#+1) {action type}
@d pdf_action_named_id(#)  == subtype(#+1) {identifier is type of name}
@d pdf_action_id(#)        == vlink(#+1) {destination/thread name identifier}
@d pdf_action_file(#)      == vinfo(# + 2) {file name for external action}
@d pdf_action_new_window(#) == vlink(# + 2) {open a new window?}
@d pdf_action_tokens(#)    == vinfo(# + 3) {specification of GoTo page or user action}
@d pdf_action_refcount(#)  == vlink(# + 3) {counter of references to this action}

@# {data structure of outlines; it's not able to write out outline entries
before all outline entries are defined, so memory allocated for outline
entries can't not be deallocated and will stay in memory. For this reason we
will store data of outline entries in |pdf_mem| instead of |mem|}
@d pdfmem_outline_size     == 8 {size of memory in |pdf_mem| which
                                  |obj_outline_ptr| points to}
@d obj_outline_count        == obj_info{count of all opened children}
@d obj_outline_ptr          == obj_aux {pointer to |pdf_mem|}
@d obj_outline_title(#)     == pdf_mem[obj_outline_ptr(#)]
@d obj_outline_parent(#)    == pdf_mem[obj_outline_ptr(#) + 1]
@d obj_outline_prev(#)      == pdf_mem[obj_outline_ptr(#) + 2]
@d obj_outline_next(#)      == pdf_mem[obj_outline_ptr(#) + 3]
@d obj_outline_first(#)     == pdf_mem[obj_outline_ptr(#) + 4]
@d obj_outline_last(#)      == pdf_mem[obj_outline_ptr(#) + 5]
@d obj_outline_action_objnum(#) == pdf_mem[obj_outline_ptr(#) + 6] {object number of
action}
@d obj_outline_attr(#)      == pdf_mem[obj_outline_ptr(#) + 7]

@# {types of destinations}
@d pdf_dest_xyz             == 0
@d pdf_dest_fit             == 1
@d pdf_dest_fith            == 2
@d pdf_dest_fitv            == 3
@d pdf_dest_fitb            == 4
@d pdf_dest_fitbh           == 5
@d pdf_dest_fitbv           == 6
@d pdf_dest_fitr            == 7

@# {data structure of destinations}
@d obj_dest_ptr             == obj_aux {pointer to |pdf_dest_node|}
@d pdf_dest_type(#)          == type(# + 6) {type of destination}
@d pdf_dest_named_id(#)      == subtype(# + 6) {is named identifier?}
@d pdf_dest_id(#)            == vlink(# + 6) {destination identifier}
@d pdf_dest_xyz_zoom(#)      == vinfo(# + 7) {zoom factor for |destxyz| destination}
@d pdf_dest_objnum(#)        == vlink(# + 7) {object number of corresponding
object}

@# {data structure of threads; words 1..4 represent the coordinates of the
    corners}
@d pdf_thread_named_id(#)    == subtype(# + 6) {is a named identifier}
@d pdf_thread_id(#)          == vlink(# + 6) {thread identifier}
@d pdf_thread_attr(#)        == vinfo(# + 7) {attributes of thread}
@d obj_thread_first          == obj_aux {pointer to the first bead}

@# {data structure of beads}
@d pdfmem_bead_size         == 5 {size of memory in |pdf_mem| which
                                  |obj_bead_ptr| points to}
@d obj_bead_ptr             == obj_aux {pointer to |pdf_mem|}
@d obj_bead_rect(#)         == pdf_mem[obj_bead_ptr(#)]
@d obj_bead_page(#)         == pdf_mem[obj_bead_ptr(#) + 1]
@d obj_bead_next(#)         == pdf_mem[obj_bead_ptr(#) + 2]
@d obj_bead_prev(#)         == pdf_mem[obj_bead_ptr(#) + 3]
@d obj_bead_attr(#)         == pdf_mem[obj_bead_ptr(#) + 4]
@d obj_bead_data            == obj_bead_rect {pointer to the corresponding
whatsit node; |obj_bead_rect| is needed only when the bead rectangle has
been written out and after that |obj_bead_data| is not needed any more
so we can use this field for both}

@<Constants...@>=
@!inf_obj_tab_size = 1000; {min size of the cross-reference table for PDF output}
@!sup_obj_tab_size = 8388607; {max size of the cross-reference table for PDF output}
@!inf_dest_names_size = 1000; {min size of the destination names table for PDF output}
@!sup_dest_names_size = 131072; {max size of the destination names table for PDF output}
@!inf_pk_dpi = 72; {min PK pixel density value from \.{texmf.cnf}}
@!sup_pk_dpi = 8000; {max PK pixel density value from \.{texmf.cnf}}
@!pdf_objtype_max = head_tab_max;

@ @<Glob...@>=
@!obj_tab_size:integer;
@!obj_tab:^obj_entry;
@!head_tab: array[1..head_tab_max] of integer;
@!pages_tail: integer;
@!obj_ptr: integer; {user objects counter}
@!sys_obj_ptr: integer; {system objects counter, including object streams}
@!pdf_last_pages: integer; {pointer to most recently generated pages object}
@!pdf_last_page: integer; {pointer to most recently generated page object}
@!pdf_last_stream: integer; {pointer to most recently generated stream}
@!pdf_stream_length: longinteger; {length of most recently generated stream}
@!pdf_stream_length_offset: longinteger; {file offset of the last stream length}
@!pdf_seek_write_length: boolean; {flag whether to seek back and write \.{/Length}}
@!pdf_last_byte: integer; {byte most recently written to PDF file; for \.{endstream} in new line}
@!pdf_append_list_arg: integer; {for use with |pdf_append_list|}
@!ff: integer; {for use with |set_ff|}
@!pdf_box_spec_media: integer;
@!pdf_box_spec_crop: integer;
@!pdf_box_spec_bleed: integer;
@!pdf_box_spec_trim: integer;
@!pdf_box_spec_art: integer;

@ @<Set init...@>=
obj_ptr := 0;
sys_obj_ptr := 0;
obj_tab_size := inf_obj_tab_size; {allocated size of |obj_tab| array}
dest_names_size := inf_dest_names_size; {allocated size of |dest_names| array}
for k := 1 to head_tab_max do
    head_tab[k] := 0;
pdf_box_spec_media  := 1;
pdf_box_spec_crop   := 2;
pdf_box_spec_bleed  := 3;
pdf_box_spec_trim   := 4;
pdf_box_spec_art    := 5;

@ Here we implement subroutines for work with objects and related things.
Some of them are used in former parts too, so we need to declare them
forward.

@d pdf_append_list_end(#) == # := append_ptr(#, pdf_append_list_arg); end
@d pdf_append_list(#) == begin pdf_append_list_arg := #; pdf_append_list_end
@d set_ff(#) == begin
    if pdf_font_num(#) < 0 then
        ff := -pdf_font_num(#)
    else
        ff := #;
end

@<Declare procedures that need to be declared forward for \pdfTeX@>=
procedure append_dest_name(s: str_number; n: integer);
var a: integer;
begin
    if pdf_dest_names_ptr = sup_dest_names_size then
        overflow("number of destination names (dest_names_size)", dest_names_size);
    if pdf_dest_names_ptr = dest_names_size then begin
        a := 0.2 * dest_names_size;
        if dest_names_size < sup_dest_names_size - a then
            dest_names_size := dest_names_size + a
        else
            dest_names_size := sup_dest_names_size;
        dest_names := xreallocarray(dest_names, dest_name_entry, dest_names_size);
    end;
    dest_names[pdf_dest_names_ptr].objname := s;
    dest_names[pdf_dest_names_ptr].objnum := n;
    incr(pdf_dest_names_ptr);
end;

procedure pdf_create_obj(t, i: integer); {create an object with type |t| and
identifier |i|}
label done;
var a, p, q: integer;
begin
    if sys_obj_ptr = sup_obj_tab_size then
        overflow("indirect objects table size", obj_tab_size);
    if sys_obj_ptr = obj_tab_size then begin
        a := 0.2 * obj_tab_size;
        if obj_tab_size < sup_obj_tab_size - a then
            obj_tab_size := obj_tab_size + a
        else
            obj_tab_size := sup_obj_tab_size;
        obj_tab := xreallocarray(obj_tab, obj_entry, obj_tab_size);
    end;
    incr(sys_obj_ptr);
    obj_ptr := sys_obj_ptr;
    obj_info(obj_ptr) := i;
    set_obj_fresh(obj_ptr);
    obj_aux(obj_ptr) := 0;
    avl_put_obj(obj_ptr, t);
    if t = obj_type_page then begin
        p := head_tab[t];
        {find the right position to insert newly created object}@/
        if (p = 0) or (obj_info(p) < i) then begin
            obj_link(obj_ptr) := p;
            head_tab[t] := obj_ptr;
        end
        else begin
            while p <> 0 do begin
                if obj_info(p) < i then
                    goto done;
                q := p;
                p := obj_link(p);
            end;
done:
            obj_link(q) := obj_ptr;
            obj_link(obj_ptr) := p;
        end;
    end
    else if t <> obj_type_others then begin
        obj_link(obj_ptr) := head_tab[t];
        head_tab[t] := obj_ptr;
        if (t = obj_type_dest) and (i < 0) then
            append_dest_name(-obj_info(obj_ptr), obj_ptr);
    end;
end;

function pdf_new_objnum: integer; {create a new object and return its number}
begin
    pdf_create_obj(obj_type_others, 0);
    pdf_new_objnum := obj_ptr;
end;

procedure pdf_os_switch(pdf_os: boolean); {switch between PDF stream and object stream mode}
begin
    if pdf_os and pdf_os_enable then begin
        if not pdf_os_mode then begin {back up PDF stream variables}
            pdf_op_ptr := pdf_ptr;
            pdf_ptr := pdf_os_ptr;
            pdf_buf := pdf_os_buf;
            pdf_buf_size := pdf_os_buf_size;
            pdf_os_mode := true; {switch to object stream}
        end;
    end else begin
        if pdf_os_mode then begin {back up object stream variables}
            pdf_os_ptr := pdf_ptr;
            pdf_ptr := pdf_op_ptr;
            pdf_buf := pdf_op_buf;
            pdf_buf_size := pdf_op_buf_size;
            pdf_os_mode := false; {switch to PDF stream}
        end;
    end;
end;

procedure pdf_os_prepare_obj(i: integer; pdf_os_level: integer); {create new \.{/ObjStm} object
if required, and set up cross reference info}
begin
    pdf_os_switch((pdf_os_level > 0) and (fixed_pdf_objcompresslevel >= pdf_os_level));
    if pdf_os_mode then begin
        if pdf_os_cur_objnum = 0 then begin
            pdf_os_cur_objnum := pdf_new_objnum;
            decr(obj_ptr); {object stream is not accessible to user}
            incr(pdf_os_cntr); {only for statistics}
            pdf_os_objidx := 0;
            pdf_ptr := 0; {start fresh object stream}
        end else
            incr(pdf_os_objidx);
        obj_os_idx(i) := pdf_os_objidx;
        obj_offset(i) := pdf_os_cur_objnum;
        pdf_os_objnum[pdf_os_objidx] := i;
        pdf_os_objoff[pdf_os_objidx] := pdf_ptr;
    end else begin
        obj_offset(i) := pdf_offset;
        obj_os_idx(i) := -1; {mark it as not included in object stream}
    end;
end;

procedure pdf_begin_obj(i: integer; pdf_os_level: integer); {begin a PDF object}
begin
    check_pdfminorversion;
    pdf_os_prepare_obj(i, pdf_os_level);
    if not pdf_os_mode then begin
        pdf_print_int(i);
        pdf_print_ln(" 0 obj");
    end else if pdf_compress_level = 0 then begin
        pdf_print("% "); {debugging help}
        pdf_print_int(i);
        pdf_print_ln(" 0 obj");
    end;
end;

procedure pdf_new_obj(t, i: integer; pdf_os: integer); {begin a new PDF object}
begin
    pdf_create_obj(t, i);
    pdf_begin_obj(obj_ptr, pdf_os);
end;

procedure pdf_end_obj; {end a PDF object}
begin
    if pdf_os_mode then begin
        if pdf_os_objidx = pdf_os_max_objs - 1 then
            pdf_os_write_objstream;
    end else
        pdf_print_ln("endobj"); {end a PDF object}
end;

procedure pdf_begin_dict(i: integer; pdf_os_level: integer); {begin a PDF dictionary object}
begin
    check_pdfminorversion;
    pdf_os_prepare_obj(i, pdf_os_level);
    if not pdf_os_mode then begin
        pdf_print_int(i);
        pdf_print(" 0 obj ");
    end else if pdf_compress_level = 0 then begin
        pdf_print("% "); {debugging help}
        pdf_print_int(i);
        pdf_print_ln(" 0 obj");
    end;
    pdf_print_ln("<<");
end;

procedure pdf_new_dict(t, i: integer; pdf_os: integer); {begin a new PDF dictionary object}
begin
    pdf_create_obj(t, i);
    pdf_begin_dict(obj_ptr, pdf_os);
end;

procedure pdf_end_dict; {end a PDF dictionary object}
begin
    if pdf_os_mode then begin
        pdf_print_ln(">>");
        if pdf_os_objidx = pdf_os_max_objs - 1 then
            pdf_os_write_objstream;
    end else
        pdf_print_ln(">> endobj");
end;

@ Write out an accumulated object stream.
First the object number and byte offset pairs are generated
and appended to the ready buffered object stream.
By this the value of \.{/First} can be calculated.
Then a new \.{/ObjStm} object is generated, and everything is
copied to the PDF output buffer, where also compression is done.
When calling this procedure, |pdf_os_mode| must be |true|.

@<Declare procedures that need to be declared forward for \pdfTeX@>=
procedure pdf_os_write_objstream;
var i, j, p, q: pointer;
begin
    if pdf_os_cur_objnum = 0 then {no object stream started}
        return;
    p := pdf_ptr;
    i := 0;
    j := 0;
    while i <= pdf_os_objidx do begin {assemble object number and byte offset pairs}
        pdf_print_int(pdf_os_objnum[i]);
        pdf_print(" ");
        pdf_print_int(pdf_os_objoff[i]);
        if j = 9 then begin {print out in groups of ten for better readability}
            pdf_out(pdf_new_line_char);
            j := 0;
        end else begin
            pdf_print(" ");
            incr(j);
        end;
        incr(i);
    end;
    pdf_buf[pdf_ptr - 1] := pdf_new_line_char; {no risk of flush, as we are in |pdf_os_mode|}
    q := pdf_ptr;
    pdf_begin_dict(pdf_os_cur_objnum, 0); {switch to PDF stream writing}
    pdf_print_ln("/Type /ObjStm");
    pdf_print("/N ");
    pdf_print_int_ln(pdf_os_objidx + 1);
    pdf_print("/First ");
    pdf_print_int_ln(q - p);
    pdf_begin_stream;
    pdf_room(q - p); {should always fit into the PDF output buffer}
    i := p;
    while i < q do begin {write object number and byte offset pairs}
        pdf_quick_out(pdf_os_buf[i]);
        incr(i);
    end;
    i := 0;
    while i < p do begin
        q := i + pdf_buf_size;
        if q > p then q := p;
        pdf_room(q - i);
        while i < q do begin {write the buffered objects}
            pdf_quick_out(pdf_os_buf[i]);
            incr(i);
        end;
    end;
    pdf_end_stream;
    pdf_os_cur_objnum := 0; {to force object stream generation next time}
end;

@ @<Declare procedures that need to be declared forward for \pdfTeX@>=
function append_ptr(p: pointer; i: integer): pointer; {appends a pointer with
info |i| to the end of linked list with head |p|}
var q: pointer;
begin
    append_ptr := p;
    fast_get_avail(q);
    info(q) := i;
    link(q) := null;
    if p = null then begin
        append_ptr := q;
        return;
    end;
    while link(p) <> null do
        p := link(p);
    link(p) := q;
end;

function pdf_lookup_list(p: pointer; i: integer): pointer; {looks up for pointer
with info |i| in list |p|}
begin
    pdf_lookup_list := null;
    while p <> null do begin
        if info(p) = i then begin
            pdf_lookup_list := p;
            return;
        end;
        p := link(p);
    end;
end;

@ @<Glob...@>=
@!pdf_image_procset: integer; {collection of image types used in current page/form}
@!pdf_text_procset: boolean; {mask of used ProcSet's in the current page/form}

@ Subroutines to print out various PDF objects

@p procedure pdf_print_fw_int(n: longinteger; w: integer); {print out an integer with
fixed width; used for outputting cross-reference table}
var k: integer; {$0\le k\le23$}
begin
    k := 0;
    repeat dig[k] := n mod 10; n := n div 10; incr(k);
    until k = w;
    pdf_room(k);
    while k > 0 do begin
        decr(k);
        pdf_quick_out("0" + dig[k]);
    end;
end;

procedure pdf_out_bytes(n: longinteger; w: integer); {print out an integer as
a number of bytes; used for outputting \.{/XRef} cross-reference stream}
var k: integer;
byte: array[0..7] of integer; {digits in a number being output}
begin
    k := 0;
    repeat byte[k] := n mod 256; n := n div 256; incr(k);
    until k = w;
    pdf_room(k);
    while k > 0 do begin
        decr(k);
        pdf_quick_out(byte[k]);
    end;
end;

procedure pdf_int_entry(s: str_number; v: integer); {print out an entry in
dictionary with integer value to PDF buffer}
begin
    pdf_out("/");
    pdf_print(s);
    pdf_out(" ");
    pdf_print_int(v);
end;

procedure pdf_int_entry_ln(s: str_number; v: integer);
begin
    pdf_int_entry(s, v);
    pdf_print_nl;
end;

procedure pdf_indirect(s: str_number; o: integer); {print out an indirect
entry in dictionary}
begin
    pdf_out("/");
    pdf_print(s);
    pdf_out(" ");
    pdf_print_int(o);
    pdf_print(" 0 R");
end;

procedure pdf_indirect_ln(s: str_number; o: integer);
begin
    pdf_indirect(s, o);
    pdf_print_nl;
end;

procedure pdf_print_str_ln(s: str_number); {print out |s| as string in PDF
output}
begin
    pdf_print_str(s);
    pdf_print_nl;
end;

procedure pdf_str_entry(s, v: str_number); {print out an entry in
dictionary with string value to PDF buffer}
begin
    if v = 0 then
        return;
    pdf_out("/");
    pdf_print(s);
    pdf_out(" ");
    pdf_print_str(v);
end;

procedure pdf_str_entry_ln(s, v: str_number);
begin
    if v = 0 then
        return;
    pdf_str_entry(s, v);
    pdf_print_nl;
end;

@* \[32e] Font processing.

As \pdfTeX{} should also act as a back-end driver, it needs to support virtual
fonts too. Information about virtual fonts can be found in the source of some
\.{DVI}-related programs.

Whenever we want to write out a character in a font to PDF output, we
should check whether the used character is a virtual or read character.
The |has_packet()| C macro checks for this condition.

@ The following code typesets a character to PDF output.

@p
procedure output_one_char(ffi:internal_font_number;c:integer);
var c_wd,c_ht,c_dp: scaled; {the real width, height and depth of the character}
ci: charinfo_short;
save, save_box_pos: scaledpos;
save_direction: integer;
begin
  ci := char_info_short(ffi,c);
  c_ht:=charinfo_height(ci);
  c_dp:=charinfo_depth(ci);
  c_wd:=charinfo_width(ci);
  synch_pos_with_cur;
  case box_direction(dvi_direction) of
  dir_TL_: begin
      case font_direction(dvi_direction) of
      dir__LL, dir__LR: pos_down((c_ht - c_dp) div 2);
      dir__LT: ;
      dir__LB: pos_down(c_ht);
      endcases;
    end;
  dir_TR_: begin
      pos_left(c_wd);
      case font_direction(dvi_direction) of
      dir__RL, dir__RR: pos_down((c_ht - c_dp) div 2);
      dir__RT: ;
      dir__RB: pos_down(c_ht);
      endcases;
    end;
  dir_BL_: begin
      case font_direction(dvi_direction) of
      dir__LL, dir__LR: pos_down((c_ht - c_dp) div 2);
      dir__LT: pos_up(c_dp);
      dir__LB: pos_down(c_ht);
      endcases;
    end;
  dir_BR_: begin
      pos_left(c_wd);
      case font_direction(dvi_direction) of
      dir__RL, dir__RR: pos_down((c_ht - c_dp) div 2);
      dir__RT: pos_up(c_dp);
      dir__RB: pos_down(c_ht);
      endcases;
    end;
  dir_LT_: begin
      pos_down(c_ht);
      case font_direction(dvi_direction) of
      dir__TL: pos_left(c_wd);
      dir__TR: ;
      dir__TB, dir__TT: pos_left(c_wd div 2);
      endcases;
    end;
  dir_RT_: begin
      pos_down(c_ht);
      case font_direction(dvi_direction) of
      dir__TL: pos_left(c_wd);
      dir__TR: ;
      dir__TB, dir__TT: pos_left(c_wd div 2);
      endcases;
    end;
  dir_LB_: begin
      pos_up(c_dp);
      case font_direction(dvi_direction) of
      dir__BL: pos_left(c_wd);
      dir__BR: ;
      dir__BB, dir__BT: pos_left(c_wd div 2);
      endcases;
    end;
  dir_RB_: begin
      pos_up(c_dp);
      case font_direction(dvi_direction) of
      dir__BL: pos_left(c_wd);
      dir__BR: ;
      dir__BB, dir__BT: pos_left(c_wd div 2);
      endcases;
    end;
  endcases;
  if has_packet(ffi,c) then begin
    save := cur;
    save_box_pos := box_pos;
    box_pos := pos;
    save_direction := dvi_direction;
    dvi_direction := dir_TL_; {local virtual font coordinate system}
    set_to_zero(cur);
    do_vf_packet(ffi, c);
    dvi_direction := save_direction;
    box_pos := save_box_pos;
    cur := save;
  end else
    pdf_place_glyph(ffi, c);
  case box_direction(dvi_direction) of
  dir_TL_, dir_TR_, dir_BL_, dir_BR_:
    cur.h := cur.h + c_wd;
  dir_LT_, dir_RT_, dir_LB_, dir_RB_:
    cur.h := cur.h + c_ht + c_dp;
  endcases;
end;

@ @<Declare procedures that need to be declared forward for \pdfTeX@>=
procedure pdf_check_vf_cur_val; forward;
procedure pdf_create_font_obj; forward;
procedure pdf_init_font_cur_val; forward;
procedure scan_pdf_ext_toks; forward;

@ Here come some subroutines to deal with expanded fonts for HZ-algorithm.

@d non_existent_path == "///..."

@p
function get_default_hyphen_char:integer;
begin
        get_default_hyphen_char:=default_hyphen_char;
end;
@#
function get_default_skew_char:integer;
begin
        get_default_skew_char:=default_skew_char;
end;
@#
procedure copy_expand_params(k, f: internal_font_number; e: integer);
{set expansion-related parameters for an expanded font |k|, based on the base
font |f| and the expansion amount |e|}
begin
    set_pdf_font_expand_ratio(k,e);
    set_pdf_font_step(k,pdf_font_step(f));
    set_pdf_font_auto_expand(k, pdf_font_auto_expand(f));
    set_pdf_font_blink(k,f);
end;

function tfm_lookup(s: str_number; fs: scaled): internal_font_number;
{looks up for a TFM with name |s| loaded at |fs| size; if found then flushes |s|}
label exit;
var k: internal_font_number;
begin
    if fs <> 0 then begin
        for k := 1 to max_font_id do
            if (tex_font_area(k) <> non_existent_path) and
               cmp_font_name(k, s) and
               (font_size(k) = fs) then begin
                flush_str(s);
                tfm_lookup := k;
                return;
            end;
    end
    else begin
        for k := 1 to max_font_id do
            if (tex_font_area(k) <> non_existent_path) and
               cmp_font_name(k, s) then begin
                    flush_string; {|font_name|}
                flush_str(s);
                tfm_lookup := k;
                return;
            end else flush_string;
    end;
    tfm_lookup := null_font;
exit:
end;

function load_expand_font(f: internal_font_number; e: integer): internal_font_number;
{loads font |f| expanded by |e| thousandths into font memory; |e| is nonzero
and is a multiple of |pdf_font_step(f)|}
label found;
var s: str_number; {font name}
    k: internal_font_number;
begin
    s := expand_font_name(f, e);
    k := tfm_lookup(s, font_size(f));
    if k = null_font then begin
        if pdf_font_auto_expand(f) then begin
            k := auto_expand_font(f, e);
                font_id_text(k) := font_id_text(f);
            end
        else
           k := read_font_info(null_cs, s, font_size(f), font_natural_dir(f));
    end;
    copy_expand_params(k, f, e);
    load_expand_font := k;
end;

function fix_expand_value(f: internal_font_number; e: integer): integer;
{return the multiple of |pdf_font_step(f)| that is nearest to |e|}
var step: integer;
    max_expand: integer;
    neg: boolean;
begin
    fix_expand_value := 0;
    if e = 0 then
        return;
    if e < 0 then begin
        e := -e;
        neg := true;
        max_expand := -pdf_font_expand_ratio(pdf_font_shrink(f));
    end
    else begin
        neg := false;
        max_expand := pdf_font_expand_ratio(pdf_font_stretch(f));
    end;
    if e > max_expand then
        e :=  max_expand
    else begin
        step := pdf_font_step(f);
        if e mod step > 0 then
            e := step*round_xn_over_d(e, 1, step);
    end;
    if neg then
        e := -e;
    fix_expand_value := e;
end;

function get_expand_font(f: internal_font_number; e: integer): internal_font_number;
{look up and create if not found an expanded version of |f|; |f| is an
expandable font; |e| is nonzero and is a multiple of |pdf_font_step(f)|}
var k: internal_font_number;
begin
    k := pdf_font_elink(f);
    while k <> null_font do begin
        if pdf_font_expand_ratio(k) = e then begin
            get_expand_font := k;
            return;
        end;
        k := pdf_font_elink(k);
    end;
    k := load_expand_font(f, e);
    set_pdf_font_elink(k,pdf_font_elink(f));
    set_pdf_font_elink(f,k);
    {|wterm_ln('get_expand_font ', e:1, ': ',f:1, ' became ', k:1);|}
    get_expand_font := k;
end;

function expand_font(f: internal_font_number; e: integer): internal_font_number;
{looks up for font |f| expanded by |e| thousandths, |e| is an arbitrary value
between max stretch and max shrink of |f|; if not found then creates it}
begin
    expand_font := f;
    if e = 0 then
        return;
    e := fix_expand_value(f, e);
    if e = 0 then
        return;
    if pdf_font_elink(f) = null_font then
        pdf_error("font expansion", "uninitialized pdf_font_elink");
    expand_font := get_expand_font(f, e);
end;

procedure set_expand_params(f: internal_font_number; auto_expand: boolean;
                            stretch_limit, shrink_limit, font_step, expand_ratio: integer);
{expand a font with given parameters}
begin
    set_pdf_font_step(f, font_step);
    set_pdf_font_auto_expand(f, auto_expand);
    if stretch_limit > 0 then
        set_pdf_font_stretch(f,get_expand_font(f, stretch_limit));
    if shrink_limit > 0 then
        set_pdf_font_shrink(f, get_expand_font(f, -shrink_limit));
    if expand_ratio <> 0 then
        set_pdf_font_expand_ratio(f,expand_ratio);
end;

procedure read_expand_font; {read font expansion spec and load expanded font}
var shrink_limit, stretch_limit, font_step: integer;
    f: internal_font_number;
    auto_expand: boolean;
begin
    {read font expansion parameters}
    scan_font_ident;
    f := cur_val;
    if f = null_font then
        pdf_error("font expansion", "invalid font identifier");
    if pdf_font_blink(f) <> null_font then
        pdf_error("font expansion", "\pdffontexpand cannot be used this way (the base font has been expanded)");
    scan_optional_equals;
    scan_int;
    stretch_limit := fix_int(cur_val, 0, 1000);
    scan_int;
    shrink_limit := fix_int(cur_val, 0, 500);
    scan_int;
    font_step := fix_int(cur_val, 0, 100);
    if font_step = 0 then
        pdf_error("font expansion", "invalid step");
    stretch_limit := stretch_limit - stretch_limit mod font_step;
    if stretch_limit < 0 then
        stretch_limit := 0;
    shrink_limit := shrink_limit - shrink_limit mod font_step;
    if shrink_limit < 0 then
        shrink_limit := 0;
    if (stretch_limit = 0) and (shrink_limit = 0) then
        pdf_error("font expansion", "invalid limit(s)");
    auto_expand := false;
    if scan_keyword('autoexpand') then begin
        auto_expand := true;
        @<Scan an optional space@>;
    end;

    {check if the font can be expanded}
    if (pdf_font_expand_ratio(f) <> 0) then
        pdf_error("font expansion", "this font has been expanded by another font so it cannot be used now");
    if (pdf_font_step(f) <> 0) then
    {this font has been expanded, ensure the expansion parameters are identical}
    begin
        if pdf_font_step(f) <> font_step then
            pdf_error("font expansion", "font has been expanded with different expansion step");

        if ((pdf_font_stretch(f) = null_font) and (stretch_limit <> 0)) or
           ((pdf_font_stretch(f) <> null_font) and
            (pdf_font_expand_ratio(pdf_font_stretch(f)) <> stretch_limit)) then
            pdf_error("font expansion", "font has been expanded with different stretch limit");

        if ((pdf_font_shrink(f) = null_font) and (shrink_limit <> 0)) or
           ((pdf_font_shrink(f) <> null_font) and
            (-pdf_font_expand_ratio(pdf_font_shrink(f)) <> shrink_limit)) then
            pdf_error("font expansion", "font has been expanded with different shrink limit");

        if pdf_font_auto_expand(f) <> auto_expand then
            pdf_error("font expansion", "font has been expanded with different auto expansion value");
    end
    else begin
        if font_used(f) then
            pdf_warning("font expansion", "font should be expanded before its first use",
                        true, true);
        set_expand_params(f, auto_expand, stretch_limit, shrink_limit, font_step, 0);
        if font_type(f) = virtual_font_type then
            vf_expand_local_fonts(f);
    end;
end;

procedure new_letterspaced_font(a: small_number);
{letter-space a font by creating a virtual font}
var u:pointer; {user's font identifier}
@!t:str_number; {name for the frozen font identifier}
@!f, k:internal_font_number;
begin
    get_r_token; u:=cur_cs;
    if u>=hash_base then t:=text(u) else t:="FONT";
@.FONTx@>
    define(u,set_font,null_font); scan_optional_equals; scan_font_ident;
    k := cur_val;
    scan_int;
    f := letter_space_font(u, k, fix_int(cur_val, -1000, 1000));
    equiv(u):=f; eqtb[font_id_base+f]:=eqtb[u]; font_id_text(f):=t;
end;

procedure make_font_copy(a: small_number);
{make a font copy for further use with font expansion}
var u:pointer; {user's font identifier}
@!t:str_number; {name for the frozen font identifier}
@!f, k:internal_font_number;
begin
    get_r_token; u:=cur_cs;
    if u>=hash_base then t:=text(u) else t:="FONT";
@.FONTx@>
    define(u,set_font,null_font); scan_optional_equals; scan_font_ident;
    k := cur_val;
    f := copy_font_info(k);
    equiv(u):=f; eqtb[font_id_base+f]:=eqtb[u]; font_id_text(f):=t;
end;


@ We need to hold information about used characters in each font for partial
downloading.

@<Types...@>=
char_map_array = array[0..32] of eight_bits; {move chars in range 0..32}
fm_entry_ptr = ^integer;

@ @<Glob...@>=
@!pdf_font_list: pointer; {list of used fonts in current page}
@!pdf_resname_prefix: str_number; {global prefix of resources name}
@!last_tokens_string: str_number; {the number of the most recently string
created by |tokens_to_string|}

@ @<Set init...@>=
pdf_resname_prefix := 0;
last_tokens_string := 0;

@ Reading VF files is done in C, using the procedure |do_vf()|

@* \[32f] PDF shipping out.
To ship out a \TeX\ box to PDF page description we need to implement
|pdf_hlist_out|, |pdf_vlist_out| and |pdf_ship_out|, which are equivalent to
the \TeX' original |hlist_out|, |vlist_out| and |ship_out| resp. But first we
need to declare some procedures needed in |pdf_hlist_out| and |pdf_vlist_out|.

@<Declare procedures needed in |pdf_hlist_out|, |pdf_vlist_out|@>=
procedure pdf_out_literal(p:pointer);
var old_setting:0..max_selector; {holds print |selector|}
    s: str_number;
begin
    if pdf_literal_type(p)=normal then begin
      old_setting:=selector; selector:=new_string;
      show_token_list(link(pdf_literal_data(p)),null,pool_size-pool_ptr);
      selector:=old_setting;
      s := make_string;
      literal(s, pdf_literal_mode(p), false);
      flush_str(s);
      end
    else begin
      pdfassert(pdf_literal_mode(p)<>scan_special);
      case pdf_literal_mode(p) of
      set_origin: begin
        pdf_goto_pagemode;
        synch_pos_with_cur;
        pdf_set_pos(pos.h, pos.v);
        end;
      direct_page:
        pdf_goto_pagemode;
      direct_always:
        pdf_end_string_nl;
      othercases confusion("literal1")
      endcases;
      lua_pdf_literal(pdf_literal_data(p));
      end;
end;

procedure pdf_out_colorstack(p:pointer);
var old_setting: 0..max_selector; {holds print |selector|}
    s: str_number;
    cmd: integer;
    stack_no: integer;
    literal_mode: integer;
begin
    cmd := pdf_colorstack_cmd(p);
    stack_no := pdf_colorstack_stack(p);
    literal_mode := 0;
    if stack_no >= colorstackused then begin
        print_nl("");
        print("Color stack ");
        print_int(stack_no);
        print(" is not initialized for use!");
        print_nl("");
        return;
    end;
    case cmd of
    colorstack_set, colorstack_push: begin
        old_setting:=selector; selector:=new_string;
        show_token_list(link(pdf_colorstack_data(p)),null,pool_size-pool_ptr);
        selector:=old_setting;
        s := make_string;
        if cmd = colorstack_set then
            literal_mode := colorstackset(stack_no, s)
        else
            literal_mode := colorstackpush(stack_no, s);
        if length(s) > 0 then
            literal(s, literal_mode, false);
        flush_str(s);
        return;
    end;
    colorstack_pop: literal_mode := colorstackpop(stack_no);
    colorstack_current: literal_mode := colorstackcurrent(stack_no);
    othercases do_nothing
    endcases;
    if cur_length > 0 then begin
        s := make_string;
        literal(s, literal_mode, false);
        flush_str(s);
    end
end;

procedure pdf_out_colorstack_startpage;
var i: integer;
    max: integer;
    start_status: integer;
    literal_mode: integer;
    s: str_number;
begin
    i := 0;
    max := colorstackused;
    while i < max do begin
        start_status := colorstackskippagestart(i);
        if start_status = 0 then begin
            literal_mode := colorstackcurrent(i);
            if cur_length > 0 then begin
                s := make_string;
                literal(s, literal_mode, false);
                flush_str(s);
            end;
        end;
        incr(i);
    end;
end;

procedure pdf_out_setmatrix(p:pointer);
var old_setting:0..max_selector; {holds print |selector|}
    s: str_number;
begin
    old_setting:=selector; selector:=new_string;
    show_token_list(link(pdf_setmatrix_data(p)),null,pool_size-pool_ptr);
    selector:=old_setting;
    str_room(7);
    str_pool[pool_ptr] := 0; { make C string for pdfsetmatrix }
    synch_pos_with_cur;
    pdfsetmatrix(str_start_macro(str_ptr), pos);
    str_room(7);
    append_char(" ");
    append_char("0");
    append_char(" ");
    append_char("0");
    append_char(" ");
    append_char("c");
    append_char("m");
    s := make_string;
    literal(s, set_origin, false);
    flush_str(s);
end;

procedure pdf_out_save;
begin
    synch_pos_with_cur;
    checkpdfsave(pos);
    literal("q", set_origin, false);
end;

procedure pdf_out_restore;
begin
    synch_pos_with_cur;
    checkpdfrestore(pos);
    literal("Q", set_origin, false);
end;

procedure pdf_special(p: pointer);
var old_setting:0..max_selector; {holds print |selector|}
    s: str_number;
begin
    old_setting:=selector; selector:=new_string;
    show_token_list(link(write_tokens(p)),null,pool_size-pool_ptr);
    selector:=old_setting;
    s := make_string;
    literal(s, scan_special, true);
    flush_str(s);
end;

procedure do_late_lua(p: pointer);
begin
   if not doing_leaders then begin
      expand_late_lua(p);
      latelua(def_ref, late_lua_name(p));
      flush_list(def_ref);
    end;
end;

procedure pdf_print_toks(p: pointer); {print tokens list |p|}
var s: str_number;
begin
    s := tokens_to_string(p);
    if length(s) > 0 then
        pdf_print(s);
    flush_str(s);
end;

procedure pdf_print_toks_ln(p: pointer); {print tokens list |p|}
var s: str_number;
begin
    s := tokens_to_string(p);
    if length(s) > 0 then begin
        pdf_print_ln(s);
    end;
    flush_str(s);
end;

@ Similiar to |vlist_out|, |pdf_vlist_out| needs to be declared forward

@p procedure@?pdf_vlist_out; forward;

@ The implementation of procedure |pdf_hlist_out| is similiar to |hlist_out|

@p @t\4@>@<Declare procedures needed in |pdf_hlist_out|, |pdf_vlist_out|@>@t@>@/

procedure pdf_hlist_out; {output an |hlist_node| box}
label move_past, fin_rule, next_p;
var base_line: scaled; {the baseline coordinate for this box}
w: scaled; { temporary value for directional width calculation }
dir_nest: integer; { for tracking nested direction nodes }
edge_v: scaled;
edge_h: scaled;
effective_horizontal: scaled;
basepoint_horizontal: scaled;
basepoint_vertical: scaled;
save_direction: integer;
dvi_ptr,dir_ptr,dir_tmp:pointer;
@!left_edge: scaled; {the left coordinate for this box}
@!save_h: scaled; {what |cur.h| should pop to}
@!save_box_pos: scaledpos; {what |box_pos| should pop to}
@!this_box: pointer; {pointer to containing box}
@!g_order: glue_ord; {applicable order of infinity for glue}
@!g_sign: normal..shrinking; {selects type of glue}
@!p,q:pointer; {current position in the hlist}
@!leader_box:pointer; {the leader box being replicated}
@!leader_wd:scaled; {width of leader box being replicated}
@!lx:scaled; {extra space between leader boxes}
@!outer_doing_leaders:boolean; {were we doing leaders?}
@!edge:scaled; {right edge of sub-box or leader space}
@!prev_p:pointer; {one step behind |p|}
@!glue_temp:real; {glue value before rounding}
@!cur_glue:real; {glue seen so far}
@!save_cur_glue:real; { saved version, for direction switch }
@!cur_g:scaled; {rounded equivalent of |cur_glue| times the glue ratio}
@!save_cur_g:scaled; { saved version, for direction switch }
@!i: small_number; {index to scan |pdf_link_stack|}
begin cur_g:=0; cur_glue:=float_constant(0);
this_box:=temp_ptr; g_order:=glue_order(this_box);
g_sign:=glue_sign(this_box); p:=list_ptr(this_box);
set_to_zero(cur); box_pos:=pos;
save_direction:=dvi_direction;
dvi_direction:=box_dir(this_box);
dvi_ptr:=0;  lx:=0;
@<DIR: Initialize |dir_ptr| for |ship_out|@>;
incr(cur_s);
base_line:=cur.v;
left_edge:=cur.h;
prev_p:=this_box+list_offset;
@<Create link annotations for the current hbox if needed@>;
@<Start hlist {\sl Sync\TeX} information record@>;
while p<>null do
    @<Output node |p| for |pdf_hlist_out| and move to the next node,
    maintaining the condition |cur.v=base_line|@>;
@<Finish hlist {\sl Sync\TeX} information record@>;
decr(cur_s);
dvi_direction:=save_direction;
@<DIR: Reset |dir_ptr|@>;
end;

@ @<Create link annotations for the current hbox if needed@>=
for i := 1 to pdf_link_stack_ptr do begin
    pdfassert(is_running(pdf_width(pdf_link_stack[i].link_node)));
    if (pdf_link_stack[i].nesting_level = cur_s) then
        append_link(this_box, left_edge, base_line, i);
end

@

@d pos_right(#) == pos.h := pos.h + (#)
@d pos_left(#)  == pos.h := pos.h - (#)
@d pos_up(#)    == pos.v := pos.v + (#)
@d pos_down(#)  == pos.v := pos.v - (#)

@<Output node |p| for |pdf_hlist_out|...@>=
begin
if is_char_node(p) then begin
  repeat
    if x_displace(p)<>0 then cur.h := cur.h + x_displace(p);
    if y_displace(p)<>0 then cur.v := cur.v - y_displace(p);
    output_one_char(font(p), character(p));
    if x_displace(p)<>0 then cur.h := cur.h - x_displace(p);
    if y_displace(p)<>0 then cur.v := cur.v + y_displace(p);
    p:=vlink(p);
  until not is_char_node(p);
  @<Record current point {\sl Sync\TeX} information@>;
end
else @<Output the non-|char_node| |p| for |pdf_hlist_out|
    and move to the next node@>;
end

@ @<Output the non-|char_node| |p| for |pdf_hlist_out|...@>=
begin case type(p) of
hlist_node_case,vlist_node_case:@<(\pdfTeX) Output a box in an hlist@>;
disc_node_case: if vlink(no_break(p))<>null then if subtype(p)<>select_disc then begin 
  q:=tail_of_list (vlink(no_break(p))); {TODO, this should be a tlink}
  vlink(q):=vlink(p);
  q:=vlink(no_break(p));
  vlink(no_break(p)):=null;
  vlink(p):=q;
  end;
rule_node_case: begin
  if not (dir_orthogonal(dir_primary[rule_dir(p)])(dir_primary[dvi_direction]))
    then begin
    rule_ht:=height(p); rule_dp:=depth(p); rule_wd:=width(p);
    end
  else begin
    rule_ht:=width(p) div 2;
    rule_dp:=width(p) div 2;
    rule_wd:=height(p)+depth(p);
    end;
  goto fin_rule;
  end;
whatsit_node_case: @<Output the whatsit node |p| in |pdf_hlist_out|@>;
glue_node_case: @<(\pdfTeX) Move right or output leaders@>;
margin_kern_node_case: cur.h := cur.h + width(p);
kern_node_case: begin
  @<Record |kern_node| {\sl Sync\TeX} information@>;
  cur.h := cur.h + width(p);
  end;
math_node_case: begin
  @<Record |math_node| {\sl Sync\TeX} information@>;
  cur.h := cur.h + surround(p);
  end;
othercases do_nothing
endcases;@/
goto next_p;
fin_rule: @<(\pdfTeX) Output a rule in an hlist@>;
move_past: begin
  cur.h := cur.h + rule_wd;
  @<Record horizontal |rule_node| or |glue_node| {\sl Sync\TeX} information@>;
  end;
next_p:prev_p:=p; p:=vlink(p);
end

@ @<(\pdfTeX) Output a box in an hlist@>=
begin
if not (dir_orthogonal(dir_primary[box_dir(p)])(dir_primary[dvi_direction]))
  then begin
  effective_horizontal:=width(p);
  basepoint_vertical:=0;
  if dir_opposite(dir_secondary[box_dir(p)])(dir_secondary[dvi_direction]) then
    basepoint_horizontal:=width(p)
  else
    basepoint_horizontal:=0;
  end
else begin
  effective_horizontal:=height(p)+depth(p);
  if not is_mirrored(box_dir(p)) then
    if dir_eq(dir_primary[box_dir(p)])(dir_secondary[dvi_direction]) then
      basepoint_horizontal:=height(p)
    else
      basepoint_horizontal:=depth(p)
  else
    if dir_eq(dir_primary[box_dir(p)])(dir_secondary[dvi_direction]) then
      basepoint_horizontal:=depth(p)
    else
      basepoint_horizontal:=height(p);
  if dir_eq(dir_secondary[box_dir(p)])(dir_primary[dvi_direction]) then
    basepoint_vertical:= -(width(p) div 2)
  else
    basepoint_vertical:= (width(p) div 2);
  end;
if not is_mirrored(dvi_direction) then
  basepoint_vertical := basepoint_vertical + shift_amount(p)
    {shift the box `down'}
else
  basepoint_vertical := basepoint_vertical - shift_amount(p);
    {shift the box `up'}
if list_ptr(p)=null then begin
  @<Record void list {\sl Sync\TeX} information@>;
  cur.h:=cur.h + effective_horizontal;
  end
else begin
  temp_ptr:=p; edge:=cur.h; cur.h:=cur.h + basepoint_horizontal;
  edge_v:=cur.v; cur.v:=base_line + basepoint_vertical;
  synch_pos_with_cur;
  save_box_pos:=box_pos;
  if type(p)=vlist_node then pdf_vlist_out@+else pdf_hlist_out;
  box_pos:=save_box_pos;
  cur.h:=edge+effective_horizontal; cur.v:=base_line;
  end
end

@ @<(\pdfTeX) Output a rule in an hlist@>=
if is_running(rule_ht) then rule_ht:=height(this_box);
if is_running(rule_dp) then rule_dp:=depth(this_box);
if ((rule_ht+rule_dp)>0)and(rule_wd>0) then begin {we don't output empty rules}
  synch_pos_with_cur;
  case box_direction(dvi_direction) of
  dir_TL_: pdf_place_rule(pos.h,           pos.v - rule_dp, rule_wd,           rule_ht + rule_dp);
  dir_BL_: pdf_place_rule(pos.h,           pos.v - rule_ht, rule_wd,           rule_ht + rule_dp);
  dir_TR_: pdf_place_rule(pos.h - rule_wd, pos.v - rule_dp, rule_wd,           rule_ht + rule_dp);
  dir_BR_: pdf_place_rule(pos.h - rule_wd, pos.v - rule_ht, rule_wd,           rule_ht + rule_dp);
  dir_LT_: pdf_place_rule(pos.h - rule_ht, pos.v - rule_wd, rule_ht + rule_dp, rule_wd);
  dir_RT_: pdf_place_rule(pos.h - rule_dp, pos.v - rule_wd, rule_ht + rule_dp, rule_wd);
  dir_LB_: pdf_place_rule(pos.h - rule_ht, pos.v,           rule_ht + rule_dp, rule_wd);
  dir_RB_: pdf_place_rule(pos.h - rule_dp, pos.v,           rule_ht + rule_dp, rule_wd);
  end;
end

@ @<(\pdfTeX) Move right or output leaders@>=
begin g:=glue_ptr(p); rule_wd:=width(g)-cur_g;
if g_sign<>normal then
  begin if g_sign=stretching then
    begin if stretch_order(g)=g_order then
      begin cur_glue:=cur_glue+stretch(g);
      vet_glue(float(glue_set(this_box))*cur_glue);
@^real multiplication@>
      cur_g:=round(glue_temp);
      end;
    end
  else if shrink_order(g)=g_order then
      begin cur_glue:=cur_glue-shrink(g);
      vet_glue(float(glue_set(this_box))*cur_glue);
      cur_g:=round(glue_temp);
      end;
  end;
rule_wd:=rule_wd+cur_g;
if subtype(p)>=a_leaders then
  @<(\pdfTeX) Output leaders in an hlist, |goto fin_rule| if a rule
    or to |next_p| if done@>;
goto move_past;
end

@ @<(\pdfTeX) Output leaders in an hlist...@>=
begin leader_box:=leader_ptr(p);
if type(leader_box)=rule_node then
  begin rule_ht:=height(leader_box); rule_dp:=depth(leader_box);
  goto fin_rule;
  end;
if not (dir_orthogonal(dir_primary[box_dir(leader_box)])(dir_primary[dvi_direction]))
  then leader_wd:=width(leader_box)
else
  leader_wd:=height(leader_box)+depth(leader_box);
if (leader_wd>0)and(rule_wd>0) then
  begin rule_wd:=rule_wd+10; {compensate for floating-point rounding}
  edge:=cur.h+rule_wd; lx:=0;
  @<Let |cur.h| be the position of the first box, and set |leader_wd+lx|
    to the spacing between corresponding parts of boxes@>;
  while cur.h+leader_wd<=edge do
    @<(\pdfTeX) Output a leader box at |cur.h|,
      then advance |cur.h| by |leader_wd+lx|@>;
  cur.h:=edge-10; goto next_p;
  end;
end

@ @<(\pdfTeX) Output a leader box at |cur.h|, ...@>=
begin
if not (dir_orthogonal(dir_primary[box_dir(leader_box)])(dir_primary[dvi_direction]))
  then begin
  basepoint_vertical:=0;
 if dir_opposite(dir_secondary[box_dir(leader_box)])(dir_secondary[dvi_direction]) then begin
    basepoint_horizontal:=width(leader_box)
    end
  else
    basepoint_horizontal:=0;
  end
else begin
  if not is_mirrored(box_dir(leader_box)) then
    if dir_eq(dir_primary[box_dir(leader_box)])(dir_secondary[dvi_direction]) then
      basepoint_horizontal:=height(leader_box)
    else
      basepoint_horizontal:=depth(leader_box)
  else
    if dir_eq(dir_primary[box_dir(leader_box)])(dir_secondary[dvi_direction]) then
      basepoint_horizontal:=depth(leader_box)
    else
      basepoint_horizontal:=height(leader_box);
  if dir_eq(dir_secondary[box_dir(leader_box)])(dir_primary[dvi_direction]) then
    basepoint_vertical:= -(width(leader_box) div 2)
  else
    basepoint_vertical:= (width(leader_box) div 2);
  end;
if not is_mirrored(dvi_direction) then
  basepoint_vertical := basepoint_vertical + shift_amount(leader_box)
    {shift the box `down'}
else
  basepoint_vertical := basepoint_vertical - shift_amount(leader_box);
    {shift the box `up'}
temp_ptr:=leader_box;
edge_h:=cur.h; cur.h:=cur.h + basepoint_horizontal;
edge_v:=cur.v; cur.v:=base_line + basepoint_vertical;
synch_pos_with_cur;
save_box_pos:=box_pos;
outer_doing_leaders:=doing_leaders; doing_leaders:=true;
if type(leader_box)=vlist_node then pdf_vlist_out@+else pdf_hlist_out;
doing_leaders:=outer_doing_leaders;
box_pos:=save_box_pos;
cur.h:=edge_h+leader_wd+lx; cur.v:=base_line;
end

@ The |pdf_vlist_out| routine is similar to |pdf_hlist_out|, but a bit simpler.
@p procedure pdf_vlist_out; {output a |pdf_vlist_node| box}
label move_past, fin_rule, next_p;
var left_edge: scaled; {the left coordinate for this box}
@!top_edge: scaled; {the top coordinate for this box}
@!save_v: scaled; {what |cur.v| should pop to}
@!save_box_pos: scaledpos; {what |box_pos| should pop to}
@!this_box: pointer; {pointer to containing box}
@!g_order: glue_ord; {applicable order of infinity for glue}
@!g_sign: normal..shrinking; {selects type of glue}
@!p:pointer; {current position in the vlist}
@!leader_box:pointer; {the leader box being replicated}
@!leader_ht:scaled; {height of leader box being replicated}
@!lx:scaled; {extra space between leader boxes}
@!outer_doing_leaders:boolean; {were we doing leaders?}
@!edge:scaled; {bottom boundary of leader space}
@!glue_temp:real; {glue value before rounding}
@!cur_glue:real; {glue seen so far}
@!cur_g:scaled; {rounded equivalent of |cur_glue| times the glue ratio}
@!save_direction: integer;
@!effective_vertical: scaled;
@!basepoint_horizontal: scaled;
@!basepoint_vertical: scaled;
@!edge_v: scaled;
begin cur_g:=0; cur_glue:=float_constant(0);
this_box:=temp_ptr; g_order:=glue_order(this_box);
g_sign:=glue_sign(this_box); p:=list_ptr(this_box);
{pdfassert(p<>0);}
set_to_zero(cur); box_pos:=pos;
{|writeln(''); writeln('vlist_out: left edge: ', cur.h:1 , '');|}
save_direction:=dvi_direction;
dvi_direction:=box_dir(this_box);
incr(cur_s);
left_edge:=cur.h;
@<Start vlist {\sl Sync\TeX} information record@>;
cur.v:=cur.v-height(this_box); top_edge:=cur.v;
@<Create thread for the current vbox if needed@>;
while p<>null do
    @<Output node |p| for |pdf_vlist_out| and move to the next node,
    maintaining the condition |cur.h=left_edge|@>;
@<Finish vlist {\sl Sync\TeX} information record@>;
decr(cur_s);
dvi_direction:=save_direction;
end;

@ @<Create thread for the current vbox if needed@>=
if (last_thread <> null) and is_running(pdf_thread_dp) and
    (pdf_thread_level = cur_s) then
    append_thread(this_box, left_edge, top_edge + height(this_box))

@ @<Output node |p| for |pdf_vlist_out|...@>=
begin if is_char_node(p) then confusion("pdfvlistout")
@:this can't happen pdfvlistout}{\quad pdfvlistout@>
else @<Output the non-|char_node| |p| for |pdf_vlist_out|@>;
next_p:p:=vlink(p);
end

@ @<Output the non-|char_node| |p| for |pdf_vlist_out|@>=
begin case type(p) of
hlist_node_case,vlist_node_case:@<(\pdfTeX) Output a box in a vlist@>;
rule_node_case: begin
  if not (dir_orthogonal(dir_primary[rule_dir(p)])(dir_primary[dvi_direction]))
    then begin
    rule_ht:=height(p); rule_dp:=depth(p); rule_wd:=width(p);
    end
  else begin
    rule_ht:=width(p) div 2;
    rule_dp:=width(p) div 2;
    rule_wd:=height(p)+depth(p);
    end;
  goto fin_rule;
  end;
whatsit_node_case: @<Output the whatsit node |p| in |pdf_vlist_out|@>;
glue_node_case: @<(\pdfTeX) Move down or output leaders@>;
kern_node_case:cur.v := cur.v + width(p);
othercases do_nothing
endcases;@/
goto next_p;
fin_rule: @<(\pdfTeX) Output a rule in a vlist, |goto next_p|@>;
move_past: cur.v := cur.v + rule_ht;
end

@ TODO: the direct test to switch between |width(p)| and |-width(p)|
is definately wrong, because it does not nest properly. But at least
it fixes a very obvious problem that otherwise occured with
\.{\\pardir TLT} in a document with \.{\\bodydir TRT}, and so it
will have to do for now.

@<(\pdfTeX) Output a box in a vlist@>=
begin
if not (dir_orthogonal(dir_primary[box_dir(p)])(dir_primary[dvi_direction]))
  then begin
  effective_vertical:=height(p)+depth(p);
  if (type(p)=hlist_node) and is_mirrored(box_dir(p)) then
    basepoint_vertical:=depth(p)
  else
    basepoint_vertical:=height(p);
  if dir_opposite(dir_secondary[box_dir(p)])(dir_secondary[dvi_direction]) then
    basepoint_horizontal:=width(p)
  else
    basepoint_horizontal:=0;
  end
else begin
  effective_vertical:=width(p);
  if not is_mirrored(box_dir(p)) then
    if dir_eq(dir_primary[box_dir(p)])(dir_secondary[dvi_direction]) then
      basepoint_horizontal:=height(p)
    else
      basepoint_horizontal:=depth(p)
  else
    if dir_eq(dir_primary[box_dir(p)])(dir_secondary[dvi_direction]) then
      basepoint_horizontal:=depth(p)
    else
      basepoint_horizontal:=height(p);
  if dir_eq(dir_secondary[box_dir(p)])(dir_primary[dvi_direction]) then
    basepoint_vertical:=0
  else
    basepoint_vertical:=width(p);
  end;
basepoint_horizontal := basepoint_horizontal + shift_amount(p);
  {shift the box `right'}
if list_ptr(p)=null then begin
  cur.v:=cur.v+effective_vertical;
  @<Record void list {\sl Sync\TeX} information@>;
  end
else begin
  edge_v:=cur.v;
  cur.h:=left_edge + basepoint_horizontal;
  cur.v:=cur.v + basepoint_vertical;
  synch_pos_with_cur;
  save_box_pos:=box_pos;
  temp_ptr:=p;
  if type(p)=vlist_node then pdf_vlist_out@+else pdf_hlist_out;
  box_pos:=save_box_pos;
  cur.h:=left_edge; cur.v:=edge_v + effective_vertical;
  end
end

@ @<(\pdfTeX) Output a rule in a vlist...@>=
if is_running(rule_wd) then rule_wd:=width(this_box);
rule_ht:=rule_ht+rule_dp; {this is the rule thickness}
if (rule_ht>0)and(rule_wd>0) then begin {we don't output empty rules}
  synch_pos_with_cur;
  case box_direction(dvi_direction) of
  dir_TL_: pdf_place_rule(pos.h,           pos.v - rule_ht, rule_wd, rule_ht);
  dir_BL_: pdf_place_rule(pos.h,           pos.v,           rule_wd, rule_ht);
  dir_TR_: pdf_place_rule(pos.h - rule_wd, pos.v - rule_ht, rule_wd, rule_ht);
  dir_BR_: pdf_place_rule(pos.h - rule_wd, pos.v,           rule_wd, rule_ht);
  dir_LT_: pdf_place_rule(pos.h,           pos.v - rule_wd, rule_ht, rule_wd);
  dir_RT_: pdf_place_rule(pos.h - rule_ht, pos.v - rule_wd, rule_ht, rule_wd);
  dir_LB_: pdf_place_rule(pos.h,           pos.v,           rule_ht, rule_wd);
  dir_RB_: pdf_place_rule(pos.h - rule_ht, pos.v,           rule_ht, rule_wd);
  end;
  cur.v := cur.v + rule_ht;
end;
goto next_p

@ @<(\pdfTeX) Move down or output leaders@>=
begin g:=glue_ptr(p); rule_ht:=width(g)-cur_g;
if g_sign<>normal then
  begin if g_sign=stretching then
    begin if stretch_order(g)=g_order then
      begin cur_glue:=cur_glue+stretch(g);
      vet_glue(float(glue_set(this_box))*cur_glue);
@^real multiplication@>
      cur_g:=round(glue_temp);
      end;
    end
  else if shrink_order(g)=g_order then
      begin cur_glue:=cur_glue-shrink(g);
      vet_glue(float(glue_set(this_box))*cur_glue);
      cur_g:=round(glue_temp);
      end;
  end;
rule_ht:=rule_ht+cur_g;
if subtype(p)>=a_leaders then
  @<(\pdfTeX) Output leaders in a vlist, |goto fin_rule| if a rule
    or to |next_p| if done@>;
goto move_past;
end

@ @<(\pdfTeX) Output leaders in a vlist...@>=
begin leader_box:=leader_ptr(p);
if type(leader_box)=rule_node then
  begin rule_wd:=width(leader_box); rule_dp:=0;
  goto fin_rule;
  end;
leader_ht:=height(leader_box)+depth(leader_box);
if (leader_ht>0)and(rule_ht>0) then
  begin rule_ht:=rule_ht+10; {compensate for floating-point rounding}
  edge:=cur.v+rule_ht; lx:=0;
  @<Let |cur.v| be the position of the first box, and set |leader_ht+lx|
    to the spacing between corresponding parts of boxes@>;
  while cur.v+leader_ht<=edge do
    @<(\pdfTeX) Output a leader box at |cur.v|,
      then advance |cur.v| by |leader_ht+lx|@>;
  cur.v:=edge-10; goto next_p;
  end;
end

@ @<(\pdfTeX) Output a leader box at |cur.v|, ...@>=
begin cur.h:=left_edge+shift_amount(leader_box);
cur.v:=cur.v+height(leader_box); save_v:=cur.v;
synch_pos_with_cur;
save_box_pos:=box_pos;
temp_ptr:=leader_box;
outer_doing_leaders:=doing_leaders; doing_leaders:=true;
if type(leader_box)=vlist_node then pdf_vlist_out@+else pdf_hlist_out;
doing_leaders:=outer_doing_leaders;
box_pos:=save_box_pos;
cur.h:=left_edge;
cur.v:=save_v-height(leader_box)+leader_ht+lx;
end

@ |fix_pdfoutput| freezes |fixed_pdfoutput| as soon as anything has been written
to the output file, be it \.{PDF} or \.{DVI}.

@p procedure fix_pdfoutput;
begin
    if not fixed_pdfoutput_set then begin
        fixed_pdfoutput := pdf_output;
        fixed_pdfoutput_set := true;
    end
    else if fixed_pdfoutput <> pdf_output then
        pdf_error("setup",
            "\pdfoutput can only be changed before anything is written to the output");
end;

@ |pdf_ship_out| is used instead of |ship_out| to shipout a box to PDF
output. If |shipping_page| is not set then the output will be a Form object,
otherwise it will be a Page object.

@p procedure pdf_ship_out(p: pointer; shipping_page: boolean); {output the box |p|}
label done, done1;
var i,j,k:integer; {general purpose accumulators}
save_font_list: pointer; {to save |pdf_font_list| during flushing pending forms}
save_obj_list: pointer; {to save |pdf_obj_list|}
save_ximage_list: pointer; {to save |pdf_ximage_list|}
save_xform_list: pointer; {to save |pdf_xform_list|}
save_image_procset: integer;  {to save |pdf_image_procset|}
save_text_procset: integer;  {to save |pdf_text_procset|}
save_cur_page_size: scaledpos; {to save |cur_page_size| during flushing pending forms}
form_margin: scaled;
pdf_last_resources: integer; {pointer to most recently generated Resources object}
pre_callback_id:integer;
post_callback_id:integer;
ret:boolean;
begin
@<Start sheet {\sl Sync\TeX} information record@>;
form_margin := one_bp;
pre_callback_id:=callback_defined(start_page_number_callback);
post_callback_id:=callback_defined(stop_page_number_callback);
if (tracing_output>0)and(pre_callback_id=0) then
  begin print_nl(""); print_ln;
  print("Completed box being shipped out");
@.Completed box...@>
  end;
check_pdfminorversion;
is_shipping_page := shipping_page;
if shipping_page then begin
  if pre_callback_id>0 then
    ret:=run_callback(pre_callback_id,'->')
  else if pre_callback_id=0 then begin
    if term_offset>max_print_line-9 then print_ln
    else if (term_offset>0)or(file_offset>0) then print_char(" ");
    print_char("["); j:=9;
    while (count(j)=0)and(j>0) do decr(j);
    for k:=0 to j do
      begin print_int(count(k));
      if k<j then print_char(".");
      end;
    end;
  update_terminal;
end;
if (tracing_output>0)and(post_callback_id=0)and shipping_page then
  begin print_char("]");
  begin_diagnostic; show_box(p); end_diagnostic(true);
  end;
@<(\pdfTeX) Ship box |p| out@>;
if (tracing_output<=0)and(post_callback_id=0) and shipping_page then
  print_char("]");
dead_cycles:=0;
update_terminal; {progress report}
@<Flush the box from memory, showing statistics if requested@>;
if shipping_page and post_callback_id>0 then
  ret:=run_callback(post_callback_id,'->');
@<Finish sheet {\sl Sync\TeX} information record@>;
end;

@ @<(\pdfTeX) Ship box |p| out@>=
if shipping_page and (box_dir(p) <> page_direction) then
  pdf_warning("\shipout", "\pagedir != \bodydir; \box255 may be placed wrongly on the page.", true, true);
@<Update the values of |max_h| and |max_v|; but if the page is too large,
  |goto done|@>;
@<Initialize variables as |pdf_ship_out| begins@>;
if type(p)=vlist_node then pdf_vlist_out@+else pdf_hlist_out;
if shipping_page then
    incr(total_pages);
cur_s:=-1;
@<Finish shipping@>;
done:

@ @<Initialize variables as |pdf_ship_out| begins@>=
prepare_mag;
temp_ptr:=p;
pdf_last_resources := pdf_new_objnum;
@<Reset resource lists@>;
dvi_direction:=page_direction;
@<Calculate PDF page dimensions and margins@>;
if not shipping_page then begin
    pdf_begin_dict(pdf_cur_form, 0);
    pdf_last_stream := pdf_cur_form;
    @<Write out Form stream header@>;
end
else begin
    pdf_last_page := get_obj(obj_type_page, total_pages + 1, 0);
    obj_aux(pdf_last_page) := 1; {mark that this page has been created}
    pdf_new_dict(obj_type_others, 0, 0);
    pdf_last_stream := obj_ptr;
    @<Reset PDF mark lists@>;
end;
@<Start stream of page/form contents@>

@ @<Reset resource lists@>=
pdf_font_list := null;
pdf_obj_list := null;
pdf_xform_list := null;
pdf_ximage_list := null;
pdf_text_procset := false;
pdf_image_procset := 0

@ @<Reset PDF mark lists@>=
pdf_annot_list := null;
pdf_link_list := null;
pdf_dest_list := null;
pdf_bead_list := null;
last_thread := null

@ @<Calculate PDF page dimensions and margins@>=
if is_shipping_page then begin
    @<Calculate DVI page dimensions and margins@>;
    {Think in upright page/paper coordinates): First preset |pos.h| and |pos.v| to the DVI origin.}
    pos.h := pdf_h_origin;
    pos.v := cur_page_size.v - pdf_v_origin;
    box_pos := pos;
    {Then calculate |cur.h| and |cur.v| within the upright coordinate system
    for the DVI origin depending on the |page_direction|.}
    dvi_direction:=page_direction;
    case box_direction(dvi_direction) of
    dir_TL_,dir_LT_: begin
      cur.h := h_offset;
      cur.v := v_offset;
      end;
    dir_TR_,dir_RT_: begin
      cur.h := cur_page_size.h - page_right_offset - one_true_inch;
      cur.v := v_offset;
      end;
    dir_BL_,dir_LB_: begin
      cur.h := h_offset;
      cur.v := cur_page_size.v - page_bottom_offset - one_true_inch;
      end;
    dir_RB_,dir_BR_: begin
      cur.h := cur_page_size.h - page_right_offset - one_true_inch;
      cur.v := cur_page_size.v - page_bottom_offset - one_true_inch;
      end;
    end;
    {The movement is actually done within the upright page coordinate system.}
    dvi_direction := dir_TL_; {only temporarily for this adjustment}
    synch_pos_with_cur; box_pos := pos; {keep track on page}
    {Then switch to page box coordinate system; do |height(p)| movement.}
    dvi_direction := page_direction;
    cur.h := 0;
    cur.v := height(p);
    synch_pos_with_cur;
    {Now we are at the point on the page where the origin of the page box should go.}
end
else begin
    dvi_direction:=box_dir(p);
    case box_direction(dvi_direction) of
    dir_TL_,dir_TR_,dir_BL_,dir_BR_: begin
      cur_page_size.h := width(p);
      cur_page_size.v := height(p) + depth(p);
      end;
    dir_LT_,dir_RT_,dir_LB_,dir_RB_: begin
      cur_page_size.h := height(p) + depth(p);
      cur_page_size.v := width(p);
      end;
    end;
    case box_direction(dvi_direction) of
    dir_TL_: begin
      pos.h := 0;
      pos.v := depth(p);
      end;
    dir_TR_: begin
      pos.h := width(p);
      pos.v := depth(p);
      end;
    dir_BL_: begin
      pos.h := 0;
      pos.v := height(p);
      end;
    dir_BR_: begin
      pos.h := width(p);
      pos.v := height(p);
      end;
    dir_LT_: begin
      pos.h := height(p);
      pos.v := width(p);
      end;
    dir_RT_: begin
      pos.h := depth(p);
      pos.v := width(p);
      end;
    dir_LB_: begin
      pos.h := height(p);
      pos.v := 0;
      end;
    dir_RB_: begin
      pos.h := depth(p);
      pos.v := 0;
      end;
    end;
end;
pdf_page_init;

@ Here we write out the header for Form.

@<Write out Form stream header@>=
pdf_print_ln("/Type /XObject");
pdf_print_ln("/Subtype /Form");
if obj_xform_attr(pdf_cur_form) <> null then begin
    pdf_print_toks_ln(obj_xform_attr(pdf_cur_form));
    delete_toks(obj_xform_attr(pdf_cur_form));
end;
pdf_print("/BBox [");
pdf_print_bp(-form_margin); pdf_print(" ");
pdf_print_bp(-form_margin); pdf_print(" ");
pdf_print_bp(cur_page_size.h + form_margin); pdf_out(" ");
pdf_print_bp(cur_page_size.v + form_margin); pdf_print_ln("]");
pdf_print_ln("/FormType 1");
pdf_print_ln("/Matrix [1 0 0 1 0 0]");
pdf_indirect_ln("Resources", pdf_last_resources)

@ @<Start stream of page/form contents@>=
pdf_begin_stream;
if shipping_page then begin
    @<Adjust transformation matrix for the magnification ratio@>;
end;
pdfshipoutbegin(shipping_page);
if shipping_page then
    pdf_out_colorstack_startpage;


@ @<Adjust transformation matrix for the magnification ratio@>=
prepare_mag;
if mag <> 1000 then begin
    pdf_print_real(mag, 3);
    pdf_print(" 0 0 ");
    pdf_print_real(mag, 3);
    pdf_print_ln(" 0 0 cm");
end

@ @<Finish shipping@>=
@<Finish stream of page/form contents@>;
if shipping_page then begin
    @<Write out page object@>;
end;
@<Write out resource lists@>;
if shipping_page then begin
    @<Write out pending PDF marks@>;
end;
@<Write out resources dictionary@>;
@<Flush resource lists@>;
if shipping_page then begin
    @<Flush PDF mark lists@>;
end

@ @<Finish stream of page/form contents@>=
pdf_goto_pagemode;
pdfshipoutend(shipping_page);
pdf_end_stream

@ @<Write out resource lists@>=
@<Write out pending raw objects@>;
@<Write out pending forms@>;
@<Write out pending images@>

@ @<Write out resources dictionary@>=
pdf_begin_dict(pdf_last_resources, 1);
@<Print additional resources@>;
@<Generate font resources@>;
@<Generate XObject resources@>;
@<Generate ProcSet@>;
pdf_end_dict

@ @<Print additional resources@>=
if shipping_page then begin
    if pdf_page_resources <> null then
        pdf_print_toks_ln(pdf_page_resources);
end
else begin
    if obj_xform_resources(pdf_cur_form) <> null then begin
        pdf_print_toks_ln(obj_xform_resources(pdf_cur_form));
        delete_toks(obj_xform_resources(pdf_cur_form));
    end;
end

@ In the end of shipping out a page we reset all the lists holding objects
have been created during the page shipping.

@d delete_toks(#) == begin delete_token_ref(#); # := null; end

@<Flush resource lists@>=
flush_list(pdf_font_list);
flush_list(pdf_obj_list);
flush_list(pdf_xform_list);
flush_list(pdf_ximage_list)

@ @<Flush PDF mark lists@>=
flush_list(pdf_annot_list);
flush_list(pdf_link_list);
flush_list(pdf_dest_list);
flush_list(pdf_bead_list)

@ @<Generate font resources@>=
if pdf_font_list <> null then begin
    pdf_print("/Font << ");
    k := pdf_font_list;
    while k <> null do begin
        pdf_print("/F");
        set_ff(info(k));
        pdf_print_int(ff);
        pdf_print_resname_prefix;
        pdf_out(" ");
        pdf_print_int(pdf_font_num(ff));
        pdf_print(" 0 R ");
        k := link(k);
    end;
    pdf_print_ln(">>");
    pdf_text_procset := true;
end

@ @<Generate XObject resources@>=
if (pdf_xform_list <> null) or (pdf_ximage_list <> null) then begin
    pdf_print("/XObject << ");
    k := pdf_xform_list;
    while k <> null do begin
        pdf_print("/Fm");
        pdf_print_int(obj_info(info(k)));
        pdf_print_resname_prefix;
        pdf_out(" ");
        pdf_print_int(info(k));
        pdf_print(" 0 R ");
        k := link(k);
    end;
    k := pdf_ximage_list;
    while k <> null do begin
        pdf_print("/Im");
        pdf_print_int(image_index(obj_data_ptr(info(k))));
        pdf_print_resname_prefix;
        pdf_out(" ");
        pdf_print_int(info(k));
        pdf_print(" 0 R ");
        update_image_procset(obj_data_ptr(info(k)));
        k := link(k);
    end;
    pdf_print_ln(">>");
end

@ @<Generate ProcSet@>=
pdf_print("/ProcSet [ /PDF");
if pdf_text_procset then
    pdf_print(" /Text");
if check_image_b(pdf_image_procset) then
    pdf_print(" /ImageB");
if check_image_c(pdf_image_procset) then
    pdf_print(" /ImageC");
if check_image_i(pdf_image_procset) then
    pdf_print(" /ImageI");
pdf_print_ln(" ]")

@ @<Write out page object@>=
pdf_begin_dict(pdf_last_page, 1);
pdf_last_pages := pdf_do_page_divert(pdf_last_page, page_divert_val);
pdf_print_ln("/Type /Page");
pdf_indirect_ln("Contents", pdf_last_stream);
pdf_indirect_ln("Resources", pdf_last_resources);
pdf_print("/MediaBox [0 0 ");
pdf_print_mag_bp(cur_page_size.h); pdf_out(" ");
pdf_print_mag_bp(cur_page_size.v);
pdf_print_ln("]");
if pdf_page_attr <> null then
    pdf_print_toks_ln(pdf_page_attr);
pdf_indirect_ln("Parent", pdf_last_pages);
if pdf_page_group_val > 0 then begin
    pdf_print("/Group ");
    pdf_print_int(pdf_page_group_val);
    pdf_print_ln(" 0 R");
    pdf_page_group_val := -1;
end;
@<Generate array of annotations or beads in page@>;
pdf_end_dict

@ @<Generate array of annotations or beads in page@>=
if (pdf_annot_list <> null) or (pdf_link_list <> null) then begin
    pdf_print("/Annots [ ");
    k := pdf_annot_list;
    while k <> null do begin
        pdf_print_int(info(k));
        pdf_print(" 0 R ");
        k := link(k);
    end;
    k := pdf_link_list;
    while k <> null do begin
        pdf_print_int(info(k));
        pdf_print(" 0 R ");
        k := link(k);
    end;
    pdf_print_ln("]");
end;
if pdf_bead_list <> null then begin
    k := pdf_bead_list;
    pdf_print("/B [ ");
    while k <> null do begin
        pdf_print_int(info(k));
        pdf_print(" 0 R ");
        k := link(k);
    end;
    pdf_print_ln("]");
end

@ @<Declare procedures needed in |pdf_hlist_out|, |pdf_vlist_out|@>=
procedure pdf_write_obj(n: integer); {write a raw PDF object}
var s: str_number;
    f: byte_file;
    data_size:integer; {total size of the data file}
    data_cur:integer; {index into |data_buffer|}
    data_buffer:^real_eight_bits; {byte buffer for data files}
    file_opened:boolean;
    k:integer;
    res:boolean;
        fnam: str_number;
    callback_id:integer;
begin
    s := tokens_to_string(obj_obj_data(n));
    delete_toks(obj_obj_data(n));
    if obj_obj_is_stream(n) > 0 then begin
        pdf_begin_dict(n, 0);
        if obj_obj_stream_attr(n) <> null then begin
            pdf_print_toks_ln(obj_obj_stream_attr(n));
            delete_toks(obj_obj_stream_attr(n));
        end;
        pdf_begin_stream;
    end
    else
        pdf_begin_obj(n, 1);
    if obj_obj_is_file(n) > 0 then begin
        data_size:=0; data_cur:=0; data_buffer:=0;
        pack_file_name(s,"","");
            callback_id:=callback_defined(find_data_file_callback);
            if callback_id>0 then begin
          res := run_callback(callback_id,'S->s',stringcast(nameoffile+1),addressof(fnam));
              if (res)and(fnam<>0)and(length(fnam)>0) then begin
                @<Fixup |nameoffile| after callback@>;
                        end;
          end;
                callback_id:=callback_defined(read_data_file_callback);
        if callback_id>0 then begin
          file_opened := false;
          res := run_callback(callback_id,'S->bSd',stringcast(nameoffile+1),
                  addressof(file_opened), addressof(data_buffer),addressof(data_size));
          if not file_opened then pdf_error("ext5", "cannot open file for embedding");
          end
        else begin
          if not tex_b_open_in(f) then
             pdf_error("ext5", "cannot open file for embedding");
          res := read_data_file(f,addressof(data_buffer),addressof(data_size));
          b_close(f);
        end;
        if not data_size then pdf_error("ext5", "empty file for embedding");
        if not res       then pdf_error("ext5", "error reading file for embedding");
        print("<<");
        print(s);
        while data_cur<data_size do begin
            pdf_out(data_buffer[data_cur]);
            incr(data_cur);
            end;
            if data_buffer<>0 then libcfree(data_buffer);
        print(">>");
    end
    else if obj_obj_is_stream(n) > 0 then
        pdf_print(s)
    else
        pdf_print_ln(s);
    if obj_obj_is_stream(n) > 0 then
        pdf_end_stream
    else
        pdf_end_obj;
    flush_str(s);
end;

@ @<Write out pending raw objects@>=
if pdf_obj_list <> null then begin
    k := pdf_obj_list;
    while k <> null do begin
        if not is_obj_written(info(k)) then
            pdf_write_obj(info(k));
        k := link(k);
    end;
end

@ When flushing pending forms we need to save and restore resource lists
(|pdf_font_list|, |pdf_obj_list|, |pdf_xform_list| and |pdf_ximage_list|),
which are also used by page shipping.
Saving and restoring |cur_page_size| is needed for proper
writing out pending PDF marks.

@<Write out pending forms@>=
if pdf_xform_list <> null then begin
    k := pdf_xform_list;
    while k <> null do begin
        if not is_obj_written(info(k)) then begin
            pdf_cur_form := info(k);
            @<Save resource lists@>;
            @<Reset resource lists@>;
            save_cur_page_size := cur_page_size;
            pdf_ship_out(obj_xform_box(pdf_cur_form), false);
            cur_page_size := save_cur_page_size;
            @<Restore resource lists@>;
        end;
        k := link(k);
    end;
end

@ @<Save resource lists@>=
save_font_list := pdf_font_list;
save_obj_list := pdf_obj_list;
save_xform_list := pdf_xform_list;
save_ximage_list := pdf_ximage_list;
save_text_procset := pdf_text_procset;
save_image_procset := pdf_image_procset

@ @<Restore resource lists@>=
pdf_font_list := save_font_list;
pdf_obj_list := save_obj_list;
pdf_xform_list := save_xform_list;
pdf_ximage_list := save_ximage_list;
pdf_text_procset := save_text_procset;
pdf_image_procset := save_image_procset

@ @<Declare procedures needed in |pdf_hlist_out|, |pdf_vlist_out|@>=
procedure pdf_write_image(n: integer); {write an image}
begin
    pdf_begin_dict(n, 0);
    if fixed_pdf_draftmode = 0 then write_image(obj_data_ptr(n));
end;

@ @<Write out pending images@>=
if pdf_ximage_list <> null then begin
    k := pdf_ximage_list;
    while k <> null do begin
        if not is_obj_written(info(k)) then
            pdf_write_image(info(k));
        k := link(k);
    end;
end

@ @<Write out pending PDF marks@>=
@<Write out PDF annotations@>;
@<Write out PDF link annotations@>;
@<Write out PDF mark destinations@>;
@<Write out PDF bead rectangle specifications@>

@ @<Write out PDF annotations@>=
if pdf_annot_list <> null then begin
    k := pdf_annot_list;
    while k <> null do begin
        i := obj_annot_ptr(info(k)); {|i| points to |pdf_annot_node|}
        pdf_begin_dict(info(k), 1);
        pdf_print_ln("/Type /Annot");
        pdf_print_toks_ln(pdf_annot_data(i));
        pdf_rectangle(i);
        pdf_end_dict;
        k := link(k);
    end;
end

@ @<Write out PDF link annotations@>=
if pdf_link_list <> null then begin
k := pdf_link_list;
while k <> null do begin
    i := obj_annot_ptr(info(k));
    pdf_begin_dict(info(k), 1);
    pdf_print_ln("/Type /Annot");
    if pdf_action_type(pdf_link_action(i)) <> pdf_action_user then
        pdf_print_ln("/Subtype /Link");
    if pdf_link_attr(i) <> null then
        pdf_print_toks_ln(pdf_link_attr(i));
    pdf_rectangle(i);
    if pdf_action_type(pdf_link_action(i)) <> pdf_action_user then
        pdf_print("/A ");
    write_action(pdf_link_action(i));
    pdf_end_dict;
    k := link(k);
    end;
    @<Flush |pdf_start_link_node|'s created by |append_link|@>;
end

@ @<Flush |pdf_start_link_node|'s created by |append_link|@>=
k := pdf_link_list;
while k <> null do begin
    i := obj_annot_ptr(info(k));
    {nodes with |subtype = pdf_link_data_node| were created by |append_link| and
     must be flushed here, as they are not linked in any list}
    if subtype(i) = pdf_link_data_node then
        flush_node(i);
    k := link(k);
end

@ @<Write out PDF mark destinations@>=
if pdf_dest_list <> null then begin
    k := pdf_dest_list;
    while k <> null do begin
        if is_obj_written(info(k)) then
            pdf_error("ext5",
                "destination has been already written (this shouldn't happen)")
        else begin
            i := obj_dest_ptr(info(k));
            if pdf_dest_named_id(i) > 0 then begin
                pdf_begin_dict(info(k), 1);
                pdf_print("/D ");
            end
            else
                pdf_begin_obj(info(k), 1);
            pdf_out("["); pdf_print_int(pdf_last_page); pdf_print(" 0 R ");
            case pdf_dest_type(i) of
            pdf_dest_xyz: begin
                pdf_print("/XYZ ");
                pdf_print_mag_bp(pdf_ann_left(i)); pdf_out(" ");
                pdf_print_mag_bp(pdf_ann_top(i)); pdf_out(" ");
                if pdf_dest_xyz_zoom(i) = null then
                    pdf_print("null")
                else begin
                    pdf_print_int(pdf_dest_xyz_zoom(i) div 1000);
                    pdf_out(".");
                    pdf_print_int((pdf_dest_xyz_zoom(i) mod 1000));
                end;
            end;
            pdf_dest_fit:
                pdf_print("/Fit");
            pdf_dest_fith: begin
                pdf_print("/FitH ");
                pdf_print_mag_bp(pdf_ann_top(i));
            end;
            pdf_dest_fitv: begin
                pdf_print("/FitV ");
                pdf_print_mag_bp(pdf_ann_left(i));
            end;
            pdf_dest_fitb:
                pdf_print("/FitB");
            pdf_dest_fitbh: begin
                pdf_print("/FitBH ");
                pdf_print_mag_bp(pdf_ann_top(i));
            end;
            pdf_dest_fitbv: begin
                pdf_print("/FitBV ");
                pdf_print_mag_bp(pdf_ann_left(i));
            end;
            pdf_dest_fitr: begin
                pdf_print("/FitR ");
                pdf_print_rect_spec(i);
            end;
            othercases pdf_error("ext5", "unknown dest type");
            endcases;
            pdf_print_ln("]");
            if pdf_dest_named_id(i) > 0 then
                pdf_end_dict
            else
                pdf_end_obj;
        end;
        k := link(k);
    end;
end

@ @<Declare procedures needed in |pdf_hlist_out|, |pdf_vlist_out|@>=
procedure pdf_print_rect_spec(r: pointer); {prints a rect spec}
begin
    pdf_print_mag_bp(pdf_ann_left(r));
    pdf_out(" ");
    pdf_print_mag_bp(pdf_ann_bottom(r));
    pdf_out(" ");
    pdf_print_mag_bp(pdf_ann_right(r));
    pdf_out(" ");
    pdf_print_mag_bp(pdf_ann_top(r));
end;

procedure pdf_rectangle(r:pointer); {output a rectangle specification to PDF file}
begin
    prepare_mag;
    pdf_print("/Rect [");
    pdf_print_rect_spec(r);
    pdf_print_ln("]");
end;

@ @<Write out PDF bead rectangle specifications@>=
if pdf_bead_list <> null then begin
    k := pdf_bead_list;
    while k <> null do begin
        pdf_new_obj(obj_type_others, 0, 1);
        pdf_out("[");
        i := obj_bead_data(info(k)); {pointer to a whatsit or whatsit-like node}
        pdf_print_rect_spec(i);
        if subtype(i) = pdf_thread_data_node then {thanh says it mis be destroyed here}
            flush_node(i);
        pdf_print_ln("]");
        obj_bead_rect(info(k)) := obj_ptr; {rewrite |obj_bead_data|}
        pdf_end_obj;
        k := link(k);
    end;
end

@ In the end we must flush PDF objects that cannot be written out
immediately after shipping out pages.

@ @<Output outlines@>=
if pdf_first_outline <> 0 then begin
    pdf_new_dict(obj_type_others, 0, 1);
    outlines := obj_ptr;
    l := pdf_first_outline; k := 0;
    repeat
        incr(k);
        a := open_subentries(l);
        if obj_outline_count(l) > 0 then
            k := k + a;
        obj_outline_parent(l) := obj_ptr;
        l := obj_outline_next(l);
    until l = 0;
    pdf_print_ln("/Type /Outlines");
    pdf_indirect_ln("First", pdf_first_outline);
    pdf_indirect_ln("Last", pdf_last_outline);
    pdf_int_entry_ln("Count", k);
    pdf_end_dict;
    @<Output PDF outline entries@>;
end
else
    outlines := 0

@ @<Output PDF outline entries@>=
k := head_tab[obj_type_outline];
while k <> 0 do begin
    if obj_outline_parent(k) = pdf_parent_outline then begin
        if obj_outline_prev(k) = 0 then
            pdf_first_outline := k;
        if obj_outline_next(k) = 0 then
            pdf_last_outline := k;
    end;
    pdf_begin_dict(k, 1);
    pdf_indirect_ln("Title", obj_outline_title(k));
    pdf_indirect_ln("A", obj_outline_action_objnum(k));
    if obj_outline_parent(k) <> 0 then
        pdf_indirect_ln("Parent", obj_outline_parent(k));
    if obj_outline_prev(k) <> 0 then
        pdf_indirect_ln("Prev", obj_outline_prev(k));
    if obj_outline_next(k) <> 0 then
        pdf_indirect_ln("Next", obj_outline_next(k));
    if obj_outline_first(k) <> 0 then
        pdf_indirect_ln("First", obj_outline_first(k));
    if obj_outline_last(k) <> 0 then
        pdf_indirect_ln("Last", obj_outline_last(k));
    if obj_outline_count(k) <> 0 then
        pdf_int_entry_ln("Count", obj_outline_count(k));
    if obj_outline_attr(k) <> 0 then begin
        pdf_print_toks_ln(obj_outline_attr(k));
        delete_toks(obj_outline_attr(k));
    end;
    pdf_end_dict;
    k := obj_link(k);
end

@ @<Output article threads@>=
if head_tab[obj_type_thread] <> 0 then begin
    pdf_new_obj(obj_type_others, 0, 1);
    threads := obj_ptr;
    pdf_out("[");
    k := head_tab[obj_type_thread];
    while k <> 0 do begin
        pdf_print_int(k);
        pdf_print(" 0 R ");
        k := obj_link(k);
    end;
    remove_last_space;
    pdf_print_ln("]");
    pdf_end_obj;
    k := head_tab[obj_type_thread];
    while k <> 0 do begin
        out_thread(k);
        k := obj_link(k);
    end;
end
else
    threads := 0

@ Now we are ready to declare our new procedure |ship_out|.  It will call
|pdf_ship_out| if the integer parameter |pdf_output| is positive; otherwise it
will call |dvi_ship_out|, which is the \TeX\ original |ship_out|.

@p procedure ship_out(p:pointer); {output the box |p|}
begin
    fix_pdfoutput;
    if pdf_output > 0 then
        pdf_ship_out(p, true)
    else
        dvi_ship_out(p);
end;

@ Finishing the PDF output file.

The following procedures sort the table of destination names
@p function str_less_str(s1, s2: str_number): boolean; {compare two strings}
var c1, c2: pool_pointer;
    l, i: integer;
begin
    c1 := str_start_macro(s1);
    c2 := str_start_macro(s2);
    if length(s1) < length(s2) then
        l := length(s1)
    else
        l := length(s2);
    i := 0;
    while (i < l) and (str_pool[c1 + i] = str_pool[c2 + i]) do
        incr(i);
    if ((i < l) and (str_pool[c1 + i] < str_pool[c2 + i])) or
        ((i = l) and (length(s1) < length(s2))) then
        str_less_str := true
    else
        str_less_str := false;
end;

procedure sort_dest_names(l, r: integer); {sorts |dest_names| by names}
var i, j: integer;
    s: str_number;
    e: dest_name_entry;
begin
    i := l;
    j := r;
    s := dest_names[(l + r) div 2].objname;
    repeat
        while str_less_str(dest_names[i].objname, s) do
            incr(i);
        while str_less_str(s, dest_names[j].objname) do
            decr(j);
        if i <= j then begin
            e := dest_names[i];
            dest_names[i] := dest_names[j];
            dest_names[j] := e;
            incr(i);
            decr(j);
        end;
    until i > j;
    if l < j then
        sort_dest_names(l, j);
    if i < r then
        sort_dest_names(i, r);
end;

@  Now the finish of PDF output file. At this moment all Page objects
are already written completely to PDF output file.

@<Finish the PDF file@>=
if total_pages=0 then begin
    if callback_id=0 then
        print_nl("No pages of output.")
    else if callback_id>0 then
        res:=run_callback(callback_id,'->');
    @.No pages of output@>
    if pdf_gone > 0 then
        garbage_warning;
end
else begin
    if fixed_pdf_draftmode = 0 then begin
        pdf_flush; {to make sure that the output file name has been already created}
        flush_jbig2_page0_objects; {flush page 0 objects from JBIG2 images, if any}
        @<Check for non-existing pages@>;
        @<Check for non-existing destinations@>;
        @<Output fonts definition@>;
        pdf_last_pages := output_pages_tree;
        @<Output outlines@>;
        @<Output name tree@>;
        @<Output article threads@>;
        @<Output the catalog object@>;
        pdf_print_info; {last candidate for object stream}
        if pdf_os_enable then begin
            pdf_os_switch(true);
            pdf_os_write_objstream;
            pdf_flush;
            pdf_os_switch(false);
            @<Output the cross-reference stream dictionary@>;
            pdf_flush;
        end else begin
            @<Output the |obj_tab|@>;
        end;
        @<Output the trailer@>;
        pdf_flush;
        if callback_id=0 then begin
            print_nl("Output written on "); print_file_name(0, output_file_name, 0);
            @.Output written on x@>
            print(" ("); print_int(total_pages); print(" page");
            if total_pages<>1 then print_char("s");
            print(", "); print_int(pdf_offset); print(" bytes).");
        end
        else if callback_id>0 then
            res:=run_callback(callback_id,'->');
    end;
    libpdffinish;
    if fixed_pdf_draftmode = 0 then b_close(pdf_file)
    else pdf_warning(0, "\pdfdraftmode enabled, not changing output pdf", true, true)
end

@ Destinations that have been referenced but don't exists have
|obj_dest_ptr=null|. Leaving them undefined might cause troubles for
PDF browsers, so we need to fix them.

@p procedure pdf_fix_dest(k: integer);
begin
    if obj_dest_ptr(k) <> null then
        return;
    pdf_warning("dest", "", false, false);
    if obj_info(k) < 0 then begin
        print("name{");
        print(-obj_info(k));
        print("}");
    end
    else begin
        print("num");
        print_int(obj_info(k));
    end;
    print(" has been referenced but does not exist, replaced by a fixed one");
    print_ln; print_ln;
    pdf_begin_obj(k, 1);
    pdf_out("[");
    pdf_print_int(head_tab[obj_type_page]);
    pdf_print_ln(" 0 R /Fit]");
    pdf_end_obj;
end;

@ @<Check for non-existing destinations@>=
k := head_tab[obj_type_dest];
while k <> 0 do begin
    pdf_fix_dest(k);
    k := obj_link(k);
end

@ @<Check for non-existing pages@>=
k := head_tab[obj_type_page];
while obj_aux(k) = 0 do begin
    pdf_warning("dest", "Page ", false, false);
    print_int(obj_info(k));
    print(" has been referenced but does not exist!");
    print_ln; print_ln;
    k := obj_link(k);
end;
head_tab[obj_type_page] := k

@ @<Output fonts definition@>=
for k := 1 to max_font_id do
    if font_used(k) and (pdf_font_num(k) < 0) then begin
        i := -pdf_font_num(k);
        pdfassert(pdf_font_num(i) > 0);
        for j := font_bc(k) to font_ec(k) do
            if pdf_char_marked(k, j) then
                pdf_mark_char(i, j);
        if (pdf_font_attr(i) = 0) and (pdf_font_attr(k) <> 0) then
            set_pdf_font_attr(i, pdf_font_attr(k))
        else if (pdf_font_attr(k) = 0) and (pdf_font_attr(i) <> 0) then
            set_pdf_font_attr(k,pdf_font_attr(i))
        else if (pdf_font_attr(i) <> 0) and (pdf_font_attr(k) <> 0) and
           not str_eq_str(pdf_font_attr(i), pdf_font_attr(k)) then begin
           pdf_warning("\pdffontattr", "fonts ", false, false);
           print_font_identifier(i);
           print(" and ");
           print_font_identifier(k);
           print(" have conflicting attributes; I will ignore the attributes assigned to ");
           print_font_identifier(i);
           print_ln; print_ln;
        end;
    end;
fixed_gen_tounicode := pdf_gen_tounicode;
k := head_tab[obj_type_font];
while k <> 0 do begin
    f := obj_info(k);
    pdfassert(pdf_font_num(f) > 0);
    do_pdf_font(k, f);
    k := obj_link(k);
end;
write_fontstuff

@ @p
procedure print_pdf_pages_attr;
begin
    if pdf_pages_attr <> null then
        pdf_print_toks_ln(pdf_pages_attr);
end;

@ The name tree is very similiar to Pages tree so its construction should be
certain from Pages tree construction. For intermediate node |obj_info| will be
the first name and |obj_link| will be the last name in \.{\\Limits} array.
Note that |pdf_dest_names_ptr| will be less than |obj_ptr|, so we test if
|k < pdf_dest_names_ptr| then |k| is index of leaf in |dest_names|; else
|k| will be index in |obj_tab| of some intermediate node.

@<Output name tree@>=
if pdf_dest_names_ptr = 0 then begin
    dests := 0;
    goto done1;
end;
sort_dest_names(0, pdf_dest_names_ptr - 1);
names_head := 0;
names_tail := 0;
k := 0; {index of current child of |l|; if |k < pdf_dest_names_ptr|
         then this is pointer to |dest_names| array;
         otherwise it is the pointer to |obj_tab| (object number)}
is_names := true; {flag whether Names or Kids}
b := 0;
repeat
    repeat
        pdf_create_obj(obj_type_others, 0); {create a new node}
        l := obj_ptr;
        if b = 0 then
            b := l; {first in this level}
        if names_head = 0 then begin
            names_head := l;
            names_tail := l;
        end else begin
            obj_link(names_tail) := l;
            names_tail := l;
        end;
        obj_link(names_tail) := 0;
        @<Output the current node in this level@>;
    until b = 0;
    if k = l then begin
        dests := l;
        goto done1;
    end;
until false;
done1:
if (dests <> 0) or (pdf_names_toks <> null) then begin
    pdf_new_dict(obj_type_others, 0, 1);
    if (dests <> 0) then
        pdf_indirect_ln("Dests", dests);
    if pdf_names_toks <> null then begin
        pdf_print_toks_ln(pdf_names_toks);
        delete_toks(pdf_names_toks);
    end;
    pdf_end_dict;
    names_tree := obj_ptr;
end
else
    names_tree := 0

@ @<Output the current node in this level@>=
pdf_begin_dict(l, 1);
j := 0;
if is_names then begin
    obj_info(l) := dest_names[k].objname;
    pdf_print("/Names [");
    repeat
        pdf_print_str(dest_names[k].objname);
        pdf_out(" ");
        pdf_print_int(dest_names[k].objnum);
        pdf_print(" 0 R ");
        incr(j);
        incr(k);
    until (j = name_tree_kids_max) or (k = pdf_dest_names_ptr);
    remove_last_space;
    pdf_print_ln("]");
    obj_aux(l) := dest_names[k - 1].objname;
    if k = pdf_dest_names_ptr then begin
        is_names := false;
        k := names_head;
        b := 0;
    end;
end
else begin
    obj_info(l) := obj_info(k);
    pdf_print("/Kids [");
    repeat
        pdf_print_int(k);
        pdf_print(" 0 R ");
        incr(j);
        obj_aux(l) := obj_aux(k);
        k := obj_link(k);
    until (j = name_tree_kids_max) or (k = b) or (obj_link(k) = 0);
    remove_last_space;
    pdf_print_ln("]");
    if k = b then
        b := 0;
end;
pdf_print("/Limits [");
pdf_print_str(obj_info(l));
pdf_out(" ");
pdf_print_str(obj_aux(l));
pdf_print_ln("]");
pdf_end_dict;

@ @<Output the catalog object@>=
pdf_new_dict(obj_type_others, 0, 1);
root := obj_ptr;
pdf_print_ln("/Type /Catalog");
pdf_indirect_ln("Pages", pdf_last_pages);
if threads <> 0 then
    pdf_indirect_ln("Threads", threads);
if outlines <> 0 then
    pdf_indirect_ln("Outlines", outlines);
if names_tree <> 0 then
    pdf_indirect_ln("Names", names_tree);
if pdf_catalog_toks <> null then begin
    pdf_print_toks_ln(pdf_catalog_toks);
    delete_toks(pdf_catalog_toks);
end;
if pdf_catalog_openaction <> 0 then
    pdf_indirect_ln("OpenAction", pdf_catalog_openaction);
pdf_end_dict

@ If the same keys in a dictionary are given several times, then it is not
defined which value is choosen by an application.  Therefore the keys
|/Producer| and |/Creator| are only set if the token list
|pdf_info_toks| converted to a string does not contain these key strings.

@p function substr_of_str(s, t: str_number):boolean;
label continue,exit;
var j, k, kk: pool_pointer; {running indices}
begin
    k:=str_start_macro(t);
    while (k < str_start_macro(t+1) - length(s)) do begin
        j:=str_start_macro(s);
        kk:=k;
        while (j < str_start_macro(s+1)) do begin
            if str_pool[j] <> str_pool[kk] then
                goto continue;
            incr(j);
            incr(kk);
        end;
        substr_of_str:=true;
        return;
        continue: incr(k);
    end;
    substr_of_str:=false;
end;

procedure pdf_print_info; {print info object}
var s: str_number;
    creator_given, producer_given, creationdate_given, moddate_given, trapped_given: boolean;
begin
    s:="";
    pdf_new_dict(obj_type_others, 0, 3); {keep Info readable unless explicitely forced}
    creator_given:=false;
    producer_given:=false;
    creationdate_given:=false;
    moddate_given:=false;
    trapped_given:=false;
    if pdf_info_toks <> null then begin
        s:=tokens_to_string(pdf_info_toks);
        creator_given:=substr_of_str("/Creator", s);
        producer_given:=substr_of_str("/Producer", s);
        creationdate_given:=substr_of_str("/CreationDate", s);
        moddate_given:=substr_of_str("/ModDate", s);
        trapped_given:=substr_of_str("/Trapped", s);
    end;
    if not producer_given then begin
        @<Print the Producer key@>;
    end;
    if pdf_info_toks <> null then begin
        if length(s) > 0 then begin
            pdf_print_ln(s);
        end;
        flush_str(s);
        delete_toks(pdf_info_toks);
    end;
    if not creator_given then
        pdf_str_entry_ln("Creator", "TeX");
    if not creationdate_given then begin
        @<Print the CreationDate key@>;
    end;
    if not moddate_given then begin
        @<Print the ModDate key@>;
    end;
    if not trapped_given then begin
        pdf_print_ln("/Trapped /False");
    end;
    pdf_str_entry_ln("PTEX.Fullbanner", pdftex_banner);
    pdf_end_dict;
end;

@ @<Print the Producer key@>=
pdf_print("/Producer (LuaTeX-");
pdf_print_int(luatex_version div 100);
pdf_out(".");
pdf_print_int(luatex_version mod 100);
pdf_out(".");
pdf_print(luatex_revision);
pdf_print_ln(")")

@ @<Print the CreationDate key@>=
print_creation_date;

@ @<Print the ModDate key@>=
print_mod_date;

@ @<Glob...@>=
@!pdftex_banner: str_number;   {the complete banner}

@ @<Build a linked list of free objects@>=
l := 0;
set_obj_fresh(l); {null object at begin of list of free objects}
for k := 1 to sys_obj_ptr do
    if not is_obj_written(k) then begin
        obj_link(l) := k;
        l := k;
    end;
obj_link(l) := 0

@ @<Output the |obj_tab|@>=
@<Build a linked list of free objects@>;
pdf_save_offset := pdf_offset;
pdf_print_ln("xref");
pdf_print("0 "); pdf_print_int_ln(obj_ptr + 1);
pdf_print_fw_int(obj_link(0), 10);
pdf_print_ln(" 65535 f ");
for k := 1 to obj_ptr do begin
    if not is_obj_written(k) then begin
        pdf_print_fw_int(obj_link(k), 10);
        pdf_print_ln(" 00000 f ");
    end
    else begin
        pdf_print_fw_int(obj_offset(k), 10);
        pdf_print_ln(" 00000 n ");
    end;
end

@ @<Output the cross-reference stream dictionary@>=
pdf_new_dict(obj_type_others, 0, 0);
if ((obj_offset(sys_obj_ptr)/256) > 16777215) then
    xref_offset_width := 5
else if obj_offset(sys_obj_ptr) > 16777215 then
    xref_offset_width := 4
else if obj_offset(sys_obj_ptr) > 65535 then
    xref_offset_width := 3
else
    xref_offset_width := 2;
@<Build a linked list of free objects@>;
pdf_print_ln("/Type /XRef");
pdf_print("/Index [0 ");
pdf_print_int(obj_ptr);
pdf_print_ln("]");
pdf_int_entry_ln("Size", obj_ptr);
pdf_print("/W [1 ");
pdf_print_int(xref_offset_width);
pdf_print_ln(" 1]");
pdf_indirect_ln("Root", root);
pdf_indirect_ln("Info", obj_ptr - 1);
if pdf_trailer_toks <> null then begin
    pdf_print_toks_ln(pdf_trailer_toks);
    delete_toks(pdf_trailer_toks);
end;
print_ID(output_file_name);
pdf_print_nl;
pdf_begin_stream;
for k := 0 to sys_obj_ptr do begin
    if not is_obj_written(k) then begin {a free object}
        pdf_out(0);
        pdf_out_bytes(obj_link(k), xref_offset_width);
        pdf_out(255);
    end else begin
        if obj_os_idx(k) = -1 then begin {object not in object stream}
            pdf_out(1);
            pdf_out_bytes(obj_offset(k), xref_offset_width);
            pdf_out(0);
        end else begin {object in object stream}
            pdf_out(2);
            pdf_out_bytes(obj_offset(k), xref_offset_width);
            pdf_out(obj_os_idx(k));
        end;
    end;
end;
pdf_end_stream;

@ @<Output the trailer@>=
if not pdf_os_enable then begin
    pdf_print_ln("trailer");
    pdf_print("<< ");
    pdf_int_entry_ln("Size", sys_obj_ptr + 1);
    pdf_indirect_ln("Root", root);
    pdf_indirect_ln("Info", sys_obj_ptr);
    if pdf_trailer_toks <> null then begin
        pdf_print_toks_ln(pdf_trailer_toks);
        delete_toks(pdf_trailer_toks);
    end;
    print_ID(output_file_name);
    pdf_print_ln(" >>");
end;
pdf_print_ln("startxref");
if pdf_os_enable then
    pdf_print_int_ln(obj_offset(sys_obj_ptr))
else
    pdf_print_int_ln(pdf_save_offset);
pdf_print_ln("%%EOF")

@* \[33] Packaging.
We're essentially done with the parts of \TeX\ that are concerned with
the input (|get_next|) and the output (|ship_out|). So it's time to
get heavily into the remaining part, which does the real work of typesetting.

After lists are constructed, \TeX\ wraps them up and puts them into boxes.
Two major subroutines are given the responsibility for this task: |hpack|
applies to horizontal lists (hlists) and |vpack| applies to vertical lists
(vlists). The main duty of |hpack| and |vpack| is to compute the dimensions
of the resulting boxes, and to adjust the glue if one of those dimensions
is pre-specified. The computed sizes normally enclose all of the material
inside the new box; but some items may stick out if negative glue is used,
if the box is overfull, or if a \.{\\vbox} includes other boxes that have
been shifted left.

The subroutine call |hpack(p,w,m)| returns a pointer to an |hlist_node|
for a box containing the hlist that starts at |p|. Parameter |w| specifies
a width; and parameter |m| is either `|exactly|' or `|additional|'.  Thus,
|hpack(p,w,exactly)| produces a box whose width is exactly |w|, while
|hpack(p,w,additional)| yields a box whose width is the natural width plus
|w|.  It is convenient to define a macro called `|natural|' to cover the
most common case, so that we can say |hpack(p,natural)| to get a box that
has the natural width of list |p|.

Similarly, |vpack(p,w,m)| returns a pointer to a |vlist_node| for a
box containing the vlist that starts at |p|. In this case |w| represents
a height instead of a width; the parameter |m| is interpreted as in |hpack|.

@d exactly=0 {a box dimension is pre-specified}
@d additional=1 {a box dimension is increased from the natural one}
@d natural==0,additional {shorthand for parameters to |hpack| and |vpack|}

@<Glob...@>=
pack_direction:integer;
spec_direction:integer;

@ The parameters to |hpack| and |vpack| correspond to \TeX's primitives
like `\.{\\hbox} \.{to} \.{300pt}', `\.{\\hbox} \.{spread} \.{10pt}'; note
that `\.{\\hbox}' with no dimension following it is equivalent to
`\.{\\hbox} \.{spread} \.{0pt}'.  The |scan_spec| subroutine scans such
constructions in the user's input, including the mandatory left brace that
follows them, and it puts the specification onto |save_stack| so that the
desired box can later be obtained by executing the following code:
$$\vbox{\halign{#\hfil\cr
|save_ptr:=save_ptr-2;|\cr
|hpack(p,saved(1),saved(0)).|\cr}}$$
Special care is necessary to ensure that the special |save_stack| codes
are placed just below the new group code, because scanning can change
|save_stack| when \.{\\csname} appears.

@p procedure scan_spec(@!c:group_code;@!three_codes:boolean);
  {scans a box specification and left brace}
label found, continue;
var @!s:integer; {temporarily saved value}
i:integer; v:integer;
@!spec_code:exactly..additional;
attr_list:halfword;
begin s:=0;
if attr_list_cache=cache_disabled then update_attribute_cache;
attr_list:=attr_list_cache;
if three_codes then begin
  s:=saved(0);
continue:
  if scan_keyword('attr') then begin
    scan_register_num; i:=cur_val;
    scan_optional_equals;
    scan_int; v:=cur_val;
        if (attr_list<>null) and (attr_list=attr_list_cache) then begin
      attr_list:=copy_attribute_list(attr_list_cache);
          add_node_attr_ref(attr_list); {will be used once}
      end;
    attr_list:=do_set_attribute(attr_list,i,v);
    goto continue;
  end;
  if scan_keyword('dir') then begin
    scan_direction; spec_direction:=cur_val;
    goto continue;
    end;
  if attr_list=attr_list_cache then begin add_node_attr_ref(attr_list); end;
  end;
if scan_keyword('to') then spec_code:=exactly
@.to@>
else if scan_keyword('spread') then spec_code:=additional
@.spread@>
else  begin spec_code:=additional; cur_val:=0;
  goto found;
  end;
scan_normal_dimen;
found: if three_codes then begin
    saved(0):=s;
    saved(1):=spec_code;
    saved(2):=cur_val;
    saved(3):=spec_direction;
    @<DIR: Adjust |text_dir_ptr| for |scan_spec|@>;
    saved(5):=attr_list;
    save_ptr:=save_ptr+6;
    new_save_level(c); scan_left_brace;
    eq_word_define(dir_base+body_direction_code,spec_direction);
    eq_word_define(dir_base+par_direction_code,spec_direction);
    eq_word_define(dir_base+text_direction_code,spec_direction);
    eq_word_define(int_base+level_local_dir_code,cur_level);
    end
  else begin
    saved(0):=spec_code;
    saved(1):=cur_val;
    save_ptr:=save_ptr+2;
    new_save_level(c); scan_left_brace;
  end;
spec_direction:=-1;
end;

@ To figure out the glue setting, |hpack| and |vpack| determine how much
stretchability and shrinkability are present, considering all four orders
of infinity. The highest order of infinity that has a nonzero coefficient
is then used as if no other orders were present.

For example, suppose that the given list contains six glue nodes with
the respective stretchabilities 3pt, 8fill, 5fil, 6pt, $-3$fil, $-8$fill.
Then the total is essentially 2fil; and if a total additional space of 6pt
is to be achieved by stretching, the actual amounts of stretch will be
0pt, 0pt, 15pt, 0pt, $-9$pt, and 0pt, since only `fil' glue will be
considered. (The `fill' glue is therefore not really stretching infinitely
with respect to `fil'; nobody would actually want that to happen.)

The arrays |total_stretch| and |total_shrink| are used to determine how much
glue of each kind is present. A global variable |last_badness| is used
to implement \.{\\badness}.

@<Glob...@>=
@!total_stretch, @!total_shrink: array[glue_ord] of scaled;
  {glue found by |hpack| or |vpack|}
@!last_badness:integer; {badness of the most recently packaged box}

@ If the global variable |adjust_tail| is non-null, the |hpack| routine
also removes all occurrences of |ins_node|, |mark_node|, and |adjust_node|
items and appends the resulting material onto the list that ends at
location |adjust_tail|.

@< Glob...@>=
@!adjust_tail:pointer; {tail of adjustment list}

@ @<Set init...@>=adjust_tail:=null; last_badness:=0;

@ @<Glob...@>=
@!font_expand_ratio: integer; {current expansion ratio}
@!last_leftmost_char: pointer;
@!last_rightmost_char: pointer;

@ @<Glob...@>=
next_char_p:pointer; {pointer to the next char of an implicit kern}
prev_char_p:pointer; {pointer to the previous char of an implicit kern}

@ This procedure is called repeatedly from inside the line break algorithm.

@p procedure set_prev_char_p(p:pointer);
begin prev_char_p:=p;
end;

@ Here is |hpack|, which is place where we do font substituting when
font expansion is being used. We define some constants used when calling
|hpack| to deal with font expansion.

@d cal_expand_ratio    == 2 {calculate amount for font expansion after breaking
                             paragraph into lines}
@d subst_ex_font       == 3 {substitute fonts}

@d substituted = 3 {|subtype| of kern nodes that should be substituted}

@p function char_stretch(p:halfword): scaled;
var k: internal_font_number;
    dw: scaled;
    ef: integer;
    f: internal_font_number;
    c: integer;
begin
    f := font(p);
    c := character(p);
    char_stretch := 0;
    k := pdf_font_stretch(f);
    ef := get_ef_code(f, c);
    if (k <> null_font) and (ef > 0) then begin
        dw := char_width(k,c) - char_width(f,c);
        if dw > 0 then
            char_stretch := round_xn_over_d(dw, ef, 1000);
    end;
end;

function char_shrink(p:halfword): scaled;
var k: internal_font_number;
    dw: scaled;
    ef: integer;
    f: internal_font_number;
    c: integer;
begin
    f := font(p);
    c := character(p);
    char_shrink := 0;
    k := pdf_font_shrink(f);
    ef := get_ef_code(f, c);
    if (k <> null_font) and (ef > 0) then begin
        dw := char_width(f,c) - char_width(k,c);
        if dw > 0 then
            char_shrink := round_xn_over_d(dw, ef, 1000);
    end;
end;

function kern_stretch(p: pointer): scaled;
var l, r: pointer;
    d: scaled;
begin
    kern_stretch := 0;
    if (prev_char_p = null) or (vlink(prev_char_p) <> p) or (vlink(p) = null)
    then
        return;
    l := prev_char_p;
    r := vlink(p);
    if not (is_char_node(l) and is_char_node(r) and
            (font(l) = font(r)) and
            (pdf_font_stretch(font(l)) <> null_font))
    then
        return;
    d := get_kern(pdf_font_stretch(font(l)), character(l), character(r));
    kern_stretch := round_xn_over_d(d - width(p),
                                    get_ef_code(font(l), character(l)), 1000);
end;

function kern_shrink(p: pointer): scaled;
var l, r: pointer;
    d: scaled;
begin
    kern_shrink := 0;
    if (prev_char_p = null) or (vlink(prev_char_p) <> p) or (vlink(p) = null)
    then
        return;
    l := prev_char_p;
    r := vlink(p);
    if not (is_char_node(l) and is_char_node(r) and
            (font(l) = font(r)) and
            (pdf_font_shrink(font(l)) <> null_font))
    then
        return;
    d := get_kern(pdf_font_shrink(font(l)), character(l), character(r));
    kern_shrink := round_xn_over_d(width(p) - d,
                                    get_ef_code(font(l), character(l)), 1000);
end;

procedure do_subst_font(p: pointer; ex_ratio: integer);
var f, k: internal_font_number;
    r: pointer;
    ef: integer;
begin
    if not is_char_node(p) and (type(p) = disc_node) then begin
        r := vlink(pre_break(p));
        while r <> null do begin
            if is_char_node(r) then
                do_subst_font(r, ex_ratio);
            r := vlink(r);
        end;
        r := vlink(post_break(p));
        while r <> null do begin
            if is_char_node(r) then
                do_subst_font(r, ex_ratio);
            r := vlink(r);
        end;
        r := vlink(no_break(p));
        while r <> null do begin
            if is_char_node(r) then
                do_subst_font(r, ex_ratio);
            r := vlink(r);
        end;
        return;
    end;
    if is_char_node(p) then
        r := p
    else begin
        {|short_display_n(p, 5);|}
        pdf_error("font expansion", "invalid node type");
            return;
    end;
    f := font(r);
    ef := get_ef_code(f, character(r));
    if ef = 0 then
        return;
    if (pdf_font_expand_ratio(f)=0) and
       (pdf_font_stretch(f) <> null_font) and
       (ex_ratio > 0) then
        k := expand_font(f, ext_xn_over_d(ex_ratio*ef,
                                          pdf_font_expand_ratio(pdf_font_stretch(f)),
                                          1000000))
    else if (pdf_font_expand_ratio(f)=0) and
            (pdf_font_shrink(f) <> null_font) and (ex_ratio < 0) then
        k := expand_font(f, ext_xn_over_d(ex_ratio*ef,
                                          -pdf_font_expand_ratio(pdf_font_shrink(f)),
                                          1000000))
    else
        k := f;
    if k <> f then begin
        font(r) := k;
        if not is_char_node(p) then begin
            r := lig_ptr(p);
            while r <> null do begin
                font(r) := k;
                r := vlink(r);
            end;
        end;
    end;
end;

function char_pw(p: pointer; side: small_number): scaled;
var f: internal_font_number;
    c: integer;
begin
    char_pw := 0;
    if side = left_side then
        last_leftmost_char := null
    else
        last_rightmost_char := null;
    if p = null then
        return;
    if not is_char_node(p) then
        return;
    f := font(p);
    if side = left_side then begin
        c := get_lp_code(f, character(p));
        last_leftmost_char := p;
    end
    else begin
        c := get_rp_code(f, character(p));
        last_rightmost_char := p;
    end;
    if c = 0 then
        return;
    char_pw :=
        round_xn_over_d(quad(f), c, 1000);
end;

function new_margin_kern(w: scaled; p: pointer; side: small_number): pointer;
var k,q: pointer;
begin
    k := new_node(margin_kern_node,side);
    width(k) := w;
    if p = null then
        pdf_error("margin kerning", "invalid pointer to marginal char node");
    q := new_char(font(p), character(p)); margin_char(k):=q;
    new_margin_kern := k;
end;

function hpack(@!p:pointer;@!w:scaled;@!m:small_number):pointer;
label reswitch,common_ending,exit;
var r:pointer; {the box node that will be returned}
@!q:pointer; {trails behind |p|}
@!h,@!d,@!x:scaled; {height, depth, and natural width}
@!s:scaled; {shift amount}
@!g:pointer; {points to a glue specification}
@!o:glue_ord; {order of infinity}
@!f:internal_font_number; {the font in a |char_node|}
@!dir_tmp,dir_ptr:pointer; {for managing the direction stack}
@!hpack_dir:integer; {the current direction}
@!disc_level:integer;
pack_interrupt:array[0..255] of halfword;
font_stretch: scaled;
font_shrink: scaled;
k: scaled;
begin last_badness:=0; r:=new_node(hlist_node,min_quarterword);
if pack_direction=-1 then
  box_dir(r):=text_direction
else begin
  box_dir(r):=pack_direction; pack_direction:=-1;
  end;
hpack_dir:=box_dir(r);
dir_ptr:=null;
push_dir(hpack_dir);
q:=r+list_offset; vlink(q):=p;@/
if m = cal_expand_ratio then begin
    prev_char_p := null;
    font_stretch := 0;
    font_shrink := 0;
    font_expand_ratio := 0;
end;
h:=0; @<Clear dimensions to zero@>;
disc_level:=0;
reswitch:
while (p<>null)or(disc_level>0) do begin
  if p=null then begin
     decr(disc_level);
     p:=pack_interrupt[disc_level];
     goto reswitch;
     end;
  @<Examine node |p| in the hlist, taking account of its effect
  on the dimensions of the new box, or moving it to the adjustment list;
  then advance |p| to the next node@>;
  end;
if adjust_tail<>null then vlink(adjust_tail):=null;
if pre_adjust_tail<>null then vlink(pre_adjust_tail):=null;
height(r):=h; depth(r):=d;@/
@<Determine the value of |width(r)| and the appropriate glue setting;
  then |return| or |goto common_ending|@>;
common_ending: @<Finish issuing a diagnostic message
      for an overfull or underfull hbox@>;
exit:
if (m = cal_expand_ratio) and (font_expand_ratio <> 0) then begin
    font_expand_ratio := fix_int(font_expand_ratio, -1000, 1000);
    q := list_ptr(r);
        list_ptr(r):=null; flush_node(r);
    r:=hpack(q, w, subst_ex_font);
end;
while dir_ptr<>null do pop_dir_node;
hpack:=r;
end;

function filtered_hpack(@!p:pointer;@!qt:pointer;@!w:scaled;@!m:small_number;@!grp:integer):pointer;
var q:pointer;
begin
  new_hyphenation(p,qt);
  call_func(new_ligkern(p,qt)); {don't care about the tail in this case}
  q:=vlink(p);
  q:=lua_hpack_filter(q,w,m,grp);
  filtered_hpack:=hpack(q,w,m);
end;

@ @<Clear dimensions to zero@>=
d:=0; x:=0;
total_stretch[normal]:=0; total_shrink[normal]:=0;
total_stretch[sfi]:=0; total_shrink[sfi]:=0;
total_stretch[fil]:=0; total_shrink[fil]:=0;
total_stretch[fill]:=0; total_shrink[fill]:=0;
total_stretch[filll]:=0; total_shrink[filll]:=0

@ @<Examine node |p| in the hlist, taking account of its effect...@>=
@^inner loop@>
begin while is_char_node(p) do
  @<Incorporate character dimensions into the dimensions of
    the hbox that will contain~it, then move to the next node@>;
if p<>null then
  begin case type(p) of
  hlist_node_case,vlist_node_case,rule_node_case,unset_node_case:
    @<Incorporate box dimensions into the dimensions of
      the hbox that will contain~it@>;
  ins_node_case,mark_node_case,adjust_node_case: begin if adjust_tail<>null then
    @<Transfer node |p| to the adjustment list@>; end;
  whatsit_node_case:@<Incorporate a whatsit node into an hbox@>;
  glue_node_case:@<Incorporate glue into the horizontal totals@>;
    margin_kern_node_case: begin
    if m = cal_expand_ratio then begin
        f := font(margin_char(p));
        do_subst_font(margin_char(p), 1000);
        if f <> font(margin_char(p)) then
            font_stretch := font_stretch - width(p) -
                char_pw(margin_char(p), subtype(p));
        font(margin_char(p)) := f;
        do_subst_font(margin_char(p), -1000);
        if f <> font(margin_char(p)) then
            font_shrink := font_shrink - width(p) -
                char_pw(margin_char(p), subtype(p));
        font(margin_char(p)) := f;
      end
    else if m = subst_ex_font then begin
            do_subst_font(margin_char(p), font_expand_ratio);
            width(p) := -char_pw(margin_char(p), subtype(p));
      end;
    x := x + width(p);
    end;
  kern_node_case: begin
    if subtype(p) = normal then begin
        if m = cal_expand_ratio then begin
            font_stretch := font_stretch + kern_stretch(p);
            font_shrink := font_shrink + kern_shrink(p);
        end
        else if m = subst_ex_font then begin
            if font_expand_ratio > 0 then
                k := kern_stretch(p)
            else if font_expand_ratio < 0 then
                k := kern_shrink(p)
            else
                pdfassert(0);
            if k <> 0 then
               width(p) := get_kern(font(prev_char_p),
                                    character(prev_char_p),
                                    character(vlink(p)))
        end;
      end;
    x := x + width(p);
    end;
  math_node_case: x:=x+surround(p);
  disc_node_case:
      begin
      if m = subst_ex_font then do_subst_font(p, font_expand_ratio);
      if (subtype(p)<>select_disc)and(vlink(no_break(p))<>null) then begin
        pack_interrupt[disc_level]:=vlink(p);
        incr(disc_level);
        p:=no_break(p);
        end;
      end;
  othercases do_nothing
  endcases;@/
  p:=vlink(p);
  end;
end


@ The code here implicitly uses the fact that running dimensions are
indicated by |null_flag|, which will be ignored in the calculations
because it is a highly negative number.

@<Incorporate box dimensions into the dimensions of the hbox...@>=
begin
if (type(p)=hlist_node) or (type(p)=vlist_node) then begin
  if dir_orthogonal(dir_primary[box_dir(p)])(dir_primary[hpack_dir]) then begin
    x:=x+height(p)+depth(p);
    s:=shift_amount(p);
    if (width(p) div 2)-s>h then h:=(width(p) div 2)-s;
    if (width(p) div 2)+s>d then d:=(width(p) div 2)+s;
    end
  else if (type(p)=hlist_node) and is_mirrored(hpack_dir) then begin
    x:=x+width(p);
    s:=shift_amount(p);
    if depth(p)-s>h then h:=depth(p)-s;
    if height(p)+s>d then d:=height(p)+s;
    end
  else begin
    x:=x+width(p);
    s:=shift_amount(p);
    if height(p)-s>h then h:=height(p)-s;
    if depth(p)+s>d then d:=depth(p)+s;
    end
  end
else begin
  x:=x+width(p);
  if type(p)>=rule_node then s:=0 @+else s:=shift_amount(p);
  if height(p)-s>h then h:=height(p)-s;
  if depth(p)+s>d then d:=depth(p)+s;
  end;
end

@ The following code is part of \TeX's inner loop; i.e., adding another
character of text to the user's input will cause each of these instructions
to be exercised one more time.
@^inner loop@>

@d add_char_stretch_end(#) == char_stretch(#)
@d add_char_stretch(#) == # := # + add_char_stretch_end

@d add_char_shrink_end(#) == char_shrink(#)
@d add_char_shrink(#) == # := # + add_char_shrink_end

@<Incorporate character dimensions into the dimensions of the hbox...@>=
begin
if m >= cal_expand_ratio then begin
    prev_char_p := p;
    case m of
    cal_expand_ratio: begin
        add_char_stretch(font_stretch)(p);
        add_char_shrink(font_shrink)(p);
    end;
    subst_ex_font:
        do_subst_font(p, font_expand_ratio);
    endcases;
end;
f:=font(p);
if is_rotated(hpack_dir) then begin
  x:=x+glyph_height(p)+glyph_depth(p);@/
  s:=glyph_width(p) div 2;@+if s>h then h:=s;@+if s>d then d:=s;
  end
else if dir_opposite(dir_tertiary[hpack_dir])(dir_tertiary[box_dir(r)])
  then begin
  x:=x+glyph_width(p);@/
  s:=glyph_depth(p);@+if s>h then h:=s;
  s:=glyph_height(p);@+if s>d then d:=s;
  end
else begin
  x:=x+glyph_width(p);@/
  s:=glyph_height(p);@+if s>h then h:=s;
  s:=glyph_depth(p);@+if s>d then d:=s;
  end;
p:=vlink(p);
end

@ Although node |q| is not necessarily the immediate predecessor of node |p|,
it always points to some node in the list preceding |p|. Thus, we can delete
nodes by moving |q| when necessary. The algorithm takes linear time, and the
extra computation does not intrude on the inner loop unless it is necessary
to make a deletion.
@^inner loop@>

@<Glob...@>=
@!pre_adjust_tail: pointer;

@ @<Set init...@>=
pre_adjust_tail := null;

@ Materials in \.{\\vadjust} used with \.{pre} keyword will be appended to
|pre_adjust_tail| instead of |adjust_tail|.

@d update_adjust_list(#) == begin
    vlink(#) := adjust_ptr(p);
    while vlink(#) <> null do
        # := vlink(#);
end

@<Transfer node |p| to the adjustment list@>=
begin while vlink(q)<>p do q:=vlink(q);
    if type(p) = adjust_node then begin
        if adjust_pre(p) <> 0 then
            update_adjust_list(pre_adjust_tail)
        else
            update_adjust_list(adjust_tail);
        p := vlink(p);
        adjust_ptr(vlink(q)):=null; flush_node(vlink(q));
    end
else  begin vlink(adjust_tail):=p; adjust_tail:=p; p:=vlink(p);
  end;
vlink(q):=p; p:=q;
end

@ @<Incorporate glue into the horizontal totals@>=
begin g:=glue_ptr(p); x:=x+width(g);@/
o:=stretch_order(g); total_stretch[o]:=total_stretch[o]+stretch(g);
o:=shrink_order(g); total_shrink[o]:=total_shrink[o]+shrink(g);
if subtype(p)>=a_leaders then
  begin g:=leader_ptr(p);
  if height(g)>h then h:=height(g);
  if depth(g)>d then d:=depth(g);
  end;
end

@ When we get to the present part of the program, |x| is the natural width
of the box being packaged.

@<Determine the value of |width(r)| and the appropriate glue setting...@>=
if m=additional then w:=x+w;
width(r):=w; x:=w-x; {now |x| is the excess to be made up}
if x=0 then
  begin glue_sign(r):=normal; glue_order(r):=normal;
  set_glue_ratio_zero(glue_set(r));
  return;
  end
else if x>0 then @<Determine horizontal glue stretch setting, then |return|
    or \hbox{|goto common_ending|}@>
else @<Determine horizontal glue shrink setting, then |return|
    or \hbox{|goto common_ending|}@>

@ If |hpack| is called with |m=cal_expand_ratio| we calculate
|font_expand_ratio| and return without checking for overfull or underfull box.

@<Determine horizontal glue stretch setting...@>=
begin @<Determine the stretch order@>;
if (m = cal_expand_ratio) and (o = normal) and (font_stretch > 0) then begin
    font_expand_ratio := divide_scaled_n(x, font_stretch, 1000.0);
    return;
end;
glue_order(r):=o; glue_sign(r):=stretching;
if total_stretch[o]<>0 then glue_set(r):=unfloat(x/total_stretch[o])
@^real division@>
else  begin glue_sign(r):=normal;
  set_glue_ratio_zero(glue_set(r)); {there's nothing to stretch}
  end;
if o=normal then if list_ptr(r)<>null then
  @<Report an underfull hbox and |goto common_ending|, if this box
    is sufficiently bad@>;
return;
end

@ @<Determine the stretch order@>=
if total_stretch[filll]<>0 then o:=filll
else if total_stretch[fill]<>0 then o:=fill
else if total_stretch[fil]<>0 then o:=fil
else if total_stretch[sfi]<>0 then o:=sfi
else o:=normal

@ @<Report an underfull hbox and |goto common_ending|, if...@>=
begin last_badness:=badness(x,total_stretch[normal]);
if last_badness>hbadness then
  begin print_ln;
  if last_badness>100 then print_nl("Underfull")@+else print_nl("Loose");
  print(" \hbox (badness "); print_int(last_badness);
@.Underfull \\hbox...@>
@.Loose \\hbox...@>
  goto common_ending;
  end;
end

@ In order to provide a decent indication of where an overfull or underfull
box originated, we use a global variable |pack_begin_line| that is
set nonzero only when |hpack| is being called by the paragraph builder
or the alignment finishing routine.

@<Glob...@>=
@!pack_begin_line:integer; {source file line where the current paragraph
  or alignment began; a negative value denotes alignment}

@ @<Set init...@>=
pack_begin_line:=0;

@ @<Finish issuing a diagnostic message for an overfull or underfull hbox@>=
if output_active then print(") has occurred while \output is active")
else  begin if pack_begin_line<>0 then
    begin if pack_begin_line>0 then print(") in paragraph at lines ")
    else print(") in alignment at lines ");
    print_int(abs(pack_begin_line));
    print("--");
    end
  else print(") detected at line ");
  print_int(line);
  end;
print_ln;@/
font_in_short_display:=null_font; short_display(list_ptr(r)); print_ln;@/
begin_diagnostic; show_box(r); end_diagnostic(true)

@ @<Determine horizontal glue shrink setting...@>=
begin @<Determine the shrink order@>;
if (m = cal_expand_ratio) and (o = normal) and (font_shrink > 0) then begin
    font_expand_ratio := divide_scaled_n(x, font_shrink, 1000.0);
    return;
end;
glue_order(r):=o; glue_sign(r):=shrinking;
if total_shrink[o]<>0 then glue_set(r):=unfloat((-x)/total_shrink[o])
@^real division@>
else  begin glue_sign(r):=normal;
  set_glue_ratio_zero(glue_set(r)); {there's nothing to shrink}
  end;
if (total_shrink[o]<-x)and(o=normal)and(list_ptr(r)<>null) then
  begin last_badness:=1000000;
  set_glue_ratio_one(glue_set(r)); {use the maximum shrinkage}
  @<Report an overfull hbox and |goto common_ending|, if this box
    is sufficiently bad@>;
  end
else if o=normal then if list_ptr(r)<>null then
  @<Report a tight hbox and |goto common_ending|, if this box
    is sufficiently bad@>;
return;
end

@ @<Determine the shrink order@>=
if total_shrink[filll]<>0 then o:=filll
else if total_shrink[fill]<>0 then o:=fill
else if total_shrink[fil]<>0 then o:=fil
else if total_shrink[sfi]<>0 then o:=sfi
else o:=normal

@ @<Report an overfull hbox and |goto common_ending|, if...@>=
if (-x-total_shrink[normal]>hfuzz)or(hbadness<100) then
  begin if (overfull_rule>0)and(-x-total_shrink[normal]>hfuzz) then
    begin while vlink(q)<>null do q:=vlink(q);
    vlink(q):=new_rule;  rule_dir(vlink(q)):=box_dir(r);
    width(vlink(q)):=overfull_rule;
    end;
  print_ln; print_nl("Overfull \hbox (");
@.Overfull \\hbox...@>
  print_scaled(-x-total_shrink[normal]); print("pt too wide");
  goto common_ending;
  end

@ @<Report a tight hbox and |goto common_ending|, if...@>=
begin last_badness:=badness(-x,total_shrink[normal]);
if last_badness>hbadness then
  begin print_ln; print_nl("Tight \hbox (badness "); print_int(last_badness);
@.Tight \\hbox...@>
  goto common_ending;
  end;
end

@ The |vpack| subroutine is actually a special case of a slightly more
general routine called |vpackage|, which has four parameters. The fourth
parameter, which is |max_dimen| in the case of |vpack|, specifies the
maximum depth of the page box that is constructed. The depth is first
computed by the normal rules; if it exceeds this limit, the reference
point is simply moved down until the limiting depth is attained.

@d vpack(#)==vpackage(#,max_dimen) {special case of unconstrained depth}

@p function vpackage(@!p:pointer;@!h:scaled;@!m:small_number;@!l:scaled):
  pointer;
label common_ending, exit;
var r:pointer; {the box node that will be returned}
@!w,@!d,@!x:scaled; {width, depth, and natural height}
@!s:scaled; {shift amount}
@!g:pointer; {points to a glue specification}
@!o:glue_ord; {order of infinity}
begin last_badness:=0;
{pdfassert(p<>0);}
r:=new_node(vlist_node,0);
if pack_direction=-1 then
  box_dir(r):=body_direction
else begin
  box_dir(r):=pack_direction; pack_direction:=-1;
  end;
subtype(r):=min_quarterword; shift_amount(r):=0;
list_ptr(r):=p;@/
w:=0; @<Clear dimensions to zero@>;
while p<>null do @<Examine node |p| in the vlist, taking account of its effect
  on the dimensions of the new box; then advance |p| to the next node@>;
width(r):=w;
if d>l then
  begin x:=x+d-l; depth(r):=l;
  end
else depth(r):=d;
@<Determine the value of |height(r)| and the appropriate glue setting;
  then |return| or |goto common_ending|@>;
common_ending: @<Finish issuing a diagnostic message
      for an overfull or underfull vbox@>;
exit: vpackage:=r;
end;

function filtered_vpackage(@!p:pointer;@!h:scaled;@!m:small_number;@!l:scaled;@!grp:integer):pointer;
var q:pointer;
begin
  q:=p;
  q:=lua_vpack_filter(q,h,m,l,grp);
  filtered_vpackage:=vpackage(q,h,m,l);
end;

@ @<Examine node |p| in the vlist, taking account of its effect...@>=
begin if is_char_node(p) then confusion("vpack")
@:this can't happen vpack}{\quad vpack@>
else  case type(p) of
  hlist_node_case,vlist_node_case,rule_node_case,unset_node_case:
    @<Incorporate box dimensions into the dimensions of
      the vbox that will contain~it@>;
  whatsit_node_case:@<Incorporate a whatsit node into a vbox@>;
  glue_node_case: @<Incorporate glue into the vertical totals@>;
  kern_node_case: begin x:=x+d+width(p); d:=0;
    end;
  othercases do_nothing
  endcases;
p:=vlink(p);
end

@ @<Incorporate box dimensions into the dimensions of the vbox...@>=
begin
if (type(p)=hlist_node) or (type(p)=vlist_node) then begin
  if dir_orthogonal(dir_primary[box_dir(p)])(dir_primary[box_dir(r)]) then begin
    x:=x+d+(width(p) div 2); d:=width(p) div 2;
    s:=shift_amount(p);
    if depth(p)+height(p)+s>w then w:=depth(p)+height(p)+s;
    end
  else if (type(p)=hlist_node) and is_mirrored(box_dir(p)) then begin
    x:=x+d+depth(p); d:=height(p);
    s:=shift_amount(p);
    if width(p)+s>w then w:=width(p)+s;
    end
  else begin
    x:=x+d+height(p); d:=depth(p);
    s:=shift_amount(p);
    if width(p)+s>w then w:=width(p)+s;
    end
  end
else
  begin x:=x+d+height(p); d:=depth(p);
  if type(p)>=rule_node then s:=0 @+else s:=shift_amount(p);
  if width(p)+s>w then w:=width(p)+s;
  end;
end

@ @<Incorporate glue into the vertical totals@>=
begin x:=x+d; d:=0;@/
g:=glue_ptr(p); x:=x+width(g);@/
o:=stretch_order(g); total_stretch[o]:=total_stretch[o]+stretch(g);
o:=shrink_order(g); total_shrink[o]:=total_shrink[o]+shrink(g);
if subtype(p)>=a_leaders then
  begin g:=leader_ptr(p);
  if width(g)>w then w:=width(g);
  end;
end

@ When we get to the present part of the program, |x| is the natural height
of the box being packaged.

@<Determine the value of |height(r)| and the appropriate glue setting...@>=
if m=additional then h:=x+h;
height(r):=h; x:=h-x; {now |x| is the excess to be made up}
if x=0 then
  begin glue_sign(r):=normal; glue_order(r):=normal;
  set_glue_ratio_zero(glue_set(r));
  return;
  end
else if x>0 then @<Determine vertical glue stretch setting, then |return|
    or \hbox{|goto common_ending|}@>
else @<Determine vertical glue shrink setting, then |return|
    or \hbox{|goto common_ending|}@>

@ @<Determine vertical glue stretch setting...@>=
begin @<Determine the stretch order@>;
glue_order(r):=o; glue_sign(r):=stretching;
if total_stretch[o]<>0 then glue_set(r):=unfloat(x/total_stretch[o])
@^real division@>
else  begin glue_sign(r):=normal;
  set_glue_ratio_zero(glue_set(r)); {there's nothing to stretch}
  end;
if o=normal then if list_ptr(r)<>null then
  @<Report an underfull vbox and |goto common_ending|, if this box
    is sufficiently bad@>;
return;
end

@ @<Report an underfull vbox and |goto common_ending|, if...@>=
begin last_badness:=badness(x,total_stretch[normal]);
if last_badness>vbadness then
  begin print_ln;
  if last_badness>100 then print_nl("Underfull")@+else print_nl("Loose");
  print(" \vbox (badness "); print_int(last_badness);
@.Underfull \\vbox...@>
@.Loose \\vbox...@>
  goto common_ending;
  end;
end

@ @<Finish issuing a diagnostic message for an overfull or underfull vbox@>=
if output_active then print(") has occurred while \output is active")
else  begin if pack_begin_line<>0 then {it's actually negative}
    begin print(") in alignment at lines ");
    print_int(abs(pack_begin_line));
    print("--");
    end
  else print(") detected at line ");
  print_int(line);
  print_ln;@/
  end;
begin_diagnostic; show_box(r); end_diagnostic(true)

@ @<Determine vertical glue shrink setting...@>=
begin @<Determine the shrink order@>;
glue_order(r):=o; glue_sign(r):=shrinking;
if total_shrink[o]<>0 then glue_set(r):=unfloat((-x)/total_shrink[o])
@^real division@>
else  begin glue_sign(r):=normal;
  set_glue_ratio_zero(glue_set(r)); {there's nothing to shrink}
  end;
if (total_shrink[o]<-x)and(o=normal)and(list_ptr(r)<>null) then
  begin last_badness:=1000000;
  set_glue_ratio_one(glue_set(r)); {use the maximum shrinkage}
  @<Report an overfull vbox and |goto common_ending|, if this box
    is sufficiently bad@>;
  end
else if o=normal then if list_ptr(r)<>null then
  @<Report a tight vbox and |goto common_ending|, if this box
    is sufficiently bad@>;
return;
end

@ @<Report an overfull vbox and |goto common_ending|, if...@>=
if (-x-total_shrink[normal]>vfuzz)or(vbadness<100) then
  begin print_ln; print_nl("Overfull \vbox (");
@.Overfull \\vbox...@>
  print_scaled(-x-total_shrink[normal]); print("pt too high");
  goto common_ending;
  end

@ @<Report a tight vbox and |goto common_ending|, if...@>=
begin last_badness:=badness(-x,total_shrink[normal]);
if last_badness>vbadness then
  begin print_ln; print_nl("Tight \vbox (badness "); print_int(last_badness);
@.Tight \\vbox...@>
  goto common_ending;
  end;
end

@ When a box is being appended to the current vertical list, the
baselineskip calculation is handled by the |append_to_vlist| routine.

@p procedure append_to_vlist(@!b:pointer);
var d:scaled; {deficiency of space between baselines}
@!p:pointer; {a new glue node}
begin if prev_depth>pdf_ignored_dimen then
  begin
  if (type(b)=hlist_node) and is_mirrored(box_dir(b)) then
    d:=width(baseline_skip)-prev_depth-depth(b)
  else
    d:=width(baseline_skip)-prev_depth-height(b);
  if d<line_skip_limit then p:=new_param_glue(line_skip_code)
  else  begin p:=new_skip_param(baseline_skip_code);
    width(temp_ptr):=d; {|temp_ptr=glue_ptr(p)|}
    end;
  vlink(tail):=p; tail:=p;
  end;
vlink(tail):=b; tail:=b;
if (type(b)=hlist_node) and is_mirrored(box_dir(b)) then
  prev_depth:=height(b)
else
  prev_depth:=depth(b);
end;

@* \[34] Data structures for math mode.

Is done in C.

@* \[35] Subroutines for math mode.

Is one in C.

@* \[36] Typesetting math formulas.

Is done in C.

@* \[37] Alignment.
It's sort of a miracle whenever \.{\\halign} and \.{\\valign} work, because
they cut across so many of the control structures of \TeX.

Therefore the
present page is probably not the best place for a beginner to start reading
this program; it is better to master everything else first.

Let us focus our thoughts on an example of what the input might be, in order
to get some idea about how the alignment miracle happens. The example doesn't
do anything useful, but it is sufficiently general to indicate all of the
special cases that must be dealt with; please do not be disturbed by its
apparent complexity and meaninglessness.
$$\vbox{\halign{\.{#}\hfil\cr
{}\\tabskip 2pt plus 3pt\cr
{}\\halign to 300pt\{u1\#v1\&\cr
\hskip 50pt\\tabskip 1pt plus 1fil u2\#v2\&\cr
\hskip 50pt u3\#v3\\cr\cr
\hskip 25pt a1\&\\omit a2\&\\vrule\\cr\cr
\hskip 25pt \\noalign\{\\vskip 3pt\}\cr
\hskip 25pt b1\\span b2\\cr\cr
\hskip 25pt \\omit\&c2\\span\\omit\\cr\}\cr}}$$
Here's what happens:

\yskip
(0) When `\.{\\halign to 300pt\{}' is scanned, the |scan_spec| routine
places the 300pt dimension onto the |save_stack|, and an |align_group|
code is placed above it. This will make it possible to complete the alignment
when the matching `\.\}' is found.

(1) The preamble is scanned next. Macros in the preamble are not expanded,
@^preamble@>
except as part of a tabskip specification. For example, if \.{u2} had been
a macro in the preamble above, it would have been expanded, since \TeX\
must look for `\.{minus...}' as part of the tabskip glue. A ``preamble list''
is constructed based on the user's preamble; in our case it contains the
following seven items:
$$\vbox{\halign{\.{#}\hfil\qquad&(#)\hfil\cr
{}\\glue 2pt plus 3pt&the tabskip preceding column 1\cr
{}\\alignrecord, width $-\infty$&preamble info for column 1\cr
{}\\glue 2pt plus 3pt&the tabskip between columns 1 and 2\cr
{}\\alignrecord, width $-\infty$&preamble info for column 2\cr
{}\\glue 1pt plus 1fil&the tabskip between columns 2 and 3\cr
{}\\alignrecord, width $-\infty$&preamble info for column 3\cr
{}\\glue 1pt plus 1fil&the tabskip following column 3\cr}}$$
These ``alignrecord'' entries have the same size as an |unset_node|,
since they will later be converted into such nodes. These alignrecord
nodes have no |depth| field; this is split into |u_part| and |v_part|,
and they point to token lists for the templates of the alignment. For
example, the |u_part| field in the first alignrecord points to the
token list `\.{u1}', i.e., the template preceding the `\.\#' for
column~1.  Furthermore, They have a |span_ptr| instead of a |node_attr|
field, and these |span_ptr| fields are initially set to the value
|end_span|, for reasons explained below.

(2) \TeX\ now looks at what follows the \.{\\cr} that ended the preamble.
It is not `\.{\\noalign}' or `\.{\\omit}', so this input is put back to
be read again, and the template `\.{u1}' is fed to the scanner. Just
before reading `\.{u1}', \TeX\ goes into restricted horizontal mode.
Just after reading `\.{u1}', \TeX\ will see `\.{a1}', and then (when the
{\.\&} is sensed) \TeX\ will see `\.{v1}'. Then \TeX\ scans an |endv|
token, indicating the end of a column. At this point an |unset_node| is
created, containing the contents of the current hlist (i.e., `\.{u1a1v1}').
The natural width of this unset node replaces the |width| field of the
alignrecord for column~1; in general, the alignrecords will record the
maximum natural width that has occurred so far in a given column.

(3) Since `\.{\\omit}' follows the `\.\&', the templates for column~2
are now bypassed. Again \TeX\ goes into restricted horizontal mode and
makes an |unset_node| from the resulting hlist; but this time the
hlist contains simply `\.{a2}'. The natural width of the new unset box
is remembered in the |width| field of the alignrecord for column~2.

(4) A third |unset_node| is created for column 3, using essentially the
mechanism that worked for column~1; this unset box contains `\.{u3\\vrule
v3}'. The vertical rule in this case has running dimensions that will later
extend to the height and depth of the whole first row, since each |unset_node|
in a row will eventually inherit the height and depth of its enclosing box.

(5) The first row has now ended; it is made into a single unset box
comprising the following seven items:
$$\vbox{\halign{\hbox to 325pt{\qquad\.{#}\hfil}\cr
{}\\glue 2pt plus 3pt\cr
{}\\unsetbox for 1 column: u1a1v1\cr
{}\\glue 2pt plus 3pt\cr
{}\\unsetbox for 1 column: a2\cr
{}\\glue 1pt plus 1fil\cr
{}\\unsetbox for 1 column: u3\\vrule v3\cr
{}\\glue 1pt plus 1fil\cr}}$$
The width of this unset row is unimportant, but it has the correct height
and depth, so the correct baselineskip glue will be computed as the row
is inserted into a vertical list.

(6) Since `\.{\\noalign}' follows the current \.{\\cr}, \TeX\ appends
additional material (in this case \.{\\vskip 3pt}) to the vertical list.
While processing this material, \TeX\ will be in internal vertical
mode, and |no_align_group| will be on |save_stack|.

(7) The next row produces an unset box that looks like this:
$$\vbox{\halign{\hbox to 325pt{\qquad\.{#}\hfil}\cr
{}\\glue 2pt plus 3pt\cr
{}\\unsetbox for 2 columns: u1b1v1u2b2v2\cr
{}\\glue 1pt plus 1fil\cr
{}\\unsetbox for 1 column: {\rm(empty)}\cr
{}\\glue 1pt plus 1fil\cr}}$$
The natural width of the unset box that spans columns 1~and~2 is stored
in a ``span node,'' which we will explain later; the |span_ptr| field of the
alignrecord for column~1 now points to the new span node, and the |span_ptr|
of the span node points to |end_span|.

(8) The final row produces the unset box
$$\vbox{\halign{\hbox to 325pt{\qquad\.{#}\hfil}\cr
{}\\glue 2pt plus 3pt\cr
{}\\unsetbox for 1 column: {\rm(empty)}\cr
{}\\glue 2pt plus 3pt\cr
{}\\unsetbox for 2 columns: u2c2v2\cr
{}\\glue 1pt plus 1fil\cr}}$$
A new span node is attached to the alignrecord for column 2.

(9) The last step is to compute the true column widths and to change all the
unset boxes to hboxes, appending the whole works to the vertical list that
encloses the \.{\\halign}. The rules for deciding on the final widths of
each unset column box will be explained below.

\yskip\noindent
Note that as \.{\\halign} is being processed, we fearlessly give up control
to the rest of \TeX. At critical junctures, an alignment routine is
called upon to step in and do some little action, but most of the time
these routines just lurk in the background. It's something like
post-hypnotic suggestion.

@ We have mentioned that alignrecords contain no |height| or |depth| fields.
Their |glue_sign| and |glue_order| are pre-empted as well, since it
is necessary to store information about what to do when a template ends.
This information is called the |extra_info| field.

@d u_part(#)==vlink(#+depth_offset) {pointer to \<u_j> token list}
@d v_part(#)==vinfo(#+depth_offset) {pointer to \<v_j> token list}
@d span_ptr(#)==vinfo(#+1) {column spanning list}
@d extra_info(#)==vinfo(#+list_offset) {info to remember during template}

@ Alignments can occur within alignments, so a small stack is used to access
the alignrecord information. At each level we have a |preamble| pointer,
indicating the beginning of the preamble list; a |cur_align| pointer,
indicating the current position in the preamble list; a |cur_span| pointer,
indicating the value of |cur_align| at the beginning of a sequence of
spanned columns; a |cur_loop| pointer, indicating the tabskip glue before
an alignrecord that should be copied next if the current list is extended;
and the |align_state| variable, which indicates the nesting of braces so
that \.{\\cr} and \.{\\span} and tab marks are properly intercepted.
There also are pointers |cur_head| and |cur_tail| to the head and tail
of a list of adjustments being moved out from horizontal mode to
vertical~mode, and alike |cur_pre_head| and |cur_pre_tail| for pre-adjust
lists.

The current values of these nine quantities appear in global variables;
when they have to be pushed down, they are stored in 6-word nodes, and
|align_ptr| points to the topmost such node.

@d preamble==vlink(align_head) {the current preamble list}

@<Glob...@>=
@!cur_align:pointer; {current position in preamble list}
@!cur_span:pointer; {start of currently spanned columns in preamble list}
@!cur_loop:pointer; {place to copy when extending a periodic preamble}
@!align_ptr:pointer; {most recently pushed-down alignment stack node}
@!cur_head,@!cur_tail:pointer; {adjustment list pointers}
@!cur_pre_head,@!cur_pre_tail:pointer; {pre-adjustment list pointers}

@ The |align_state| and |preamble| variables are initialized elsewhere.

@<Set init...@>=
align_ptr:=null; cur_align:=null; cur_span:=null; cur_loop:=null;
cur_head:=null; cur_tail:=null;
cur_pre_head:=null; cur_pre_tail:=null;

@ Alignment stack maintenance is handled by a pair of trivial routines
called |push_alignment| and |pop_alignment|.

@p procedure push_alignment;
var p:pointer; {the new alignment stack node}
begin p:=new_node(align_stack_node,0);
vinfo(p+1):=align_ptr;       vlink(p+1):=cur_align;
vinfo(p+2):=preamble;        vlink(p+2):=cur_span;
vinfo(p+3):=cur_loop;        vlink(p+3):=align_state;
vinfo(p+4):=cur_head;        vlink(p+4):=cur_tail;
vinfo(p+5):=cur_pre_head;    vlink(p+5):=cur_pre_tail;
align_ptr:=p;
cur_head:=new_node(temp_node,0);
end;
@#
procedure pop_alignment;
var p:pointer; {the top alignment stack node}
begin flush_node(cur_head);
p:=align_ptr;
cur_pre_tail:=vlink(p+5); cur_pre_head:=vinfo(p+5);
cur_tail    :=vlink(p+4); cur_head    :=vinfo(p+4);
align_state :=vlink(p+3); cur_loop    :=vinfo(p+3);
cur_span    :=vlink(p+2); preamble    :=vinfo(p+2);
cur_align   :=vlink(p+1); align_ptr   :=vinfo(p+1);
flush_node(p);
end;

@ \TeX\ has eight procedures that govern alignments: |init_align| and
|fin_align| are used at the very beginning and the very end; |init_row| and
|fin_row| are used at the beginning and end of individual rows; |init_span|
is used at the beginning of a sequence of spanned columns (possibly involving
only one column); |init_col| and |fin_col| are used at the beginning and
end of individual columns; and |align_peek| is used after \.{\\cr} to see
whether the next item is \.{\\noalign}.

We shall consider these routines in the order they are first used during
the course of a complete \.{\\halign}, namely |init_align|, |align_peek|,
|init_row|, |init_span|, |init_col|, |fin_col|, |fin_row|, |fin_align|.

@ When \.{\\halign} or \.{\\valign} has been scanned in an appropriate
mode, \TeX\ calls |init_align|, whose task is to get everything off to a
good start. This mostly involves scanning the preamble and putting its
information into the preamble list.
@^preamble@>

@p @t\4@>@<Declare the procedure called |get_preamble_token|@>@t@>@/
procedure@?align_peek; forward;@t\2@>@/
procedure@?normal_paragraph; forward;@t\2@>@/
procedure init_align;
label done, done1, done2, continue;
var save_cs_ptr:pointer; {|warning_index| value for error messages}
@!p,r:pointer; {for short-term temporary use}
begin save_cs_ptr:=cur_cs; {\.{\\halign} or \.{\\valign}, usually}
push_alignment; align_state:=-1000000; {enter a new alignment level}
@<Check for improper alignment in displayed math@>;
push_nest; {enter a new semantic level}
@<Change current mode to |-vmode| for \.{\\halign}, |-hmode| for \.{\\valign}@>;
scan_spec(align_group,false);@/
@<Scan the preamble and record it in the |preamble| list@>;
new_save_level(align_group);
if every_cr<>null then begin_token_list(every_cr,every_cr_text);
align_peek; {look for \.{\\noalign} or \.{\\omit}}
end;

@ In vertical modes, |prev_depth| already has the correct value. But
if we are in |mmode| (displayed formula mode), we reach out to the
enclosing vertical mode for the |prev_depth| value that produces the
correct baseline calculations.

@<Change current mode...@>=
if mode=mmode then
  begin mode:=-vmode; prev_depth:=nest[nest_ptr-2].aux_field.sc;
  end
else if mode>0 then negate(mode)

@ When \.{\\halign} is used as a displayed formula, there should be
no other pieces of mlists present.

@<Check for improper alignment in displayed math@>=
if (mode=mmode)and((tail<>head)or(incompleat_noad<>null)) then
  begin print_err("Improper "); print_esc("halign"); print(" inside $$'s");
@.Improper \\halign...@>
  help3("Displays can use special alignments (like \eqalignno)")@/
  ("only if nothing but the alignment itself is between $$'s.")@/
  ("So I've deleted the formulas that preceded this alignment.");
  error; flush_math;
  end

@ @<Scan the preamble and record it in the |preamble| list@>=
preamble:=null; cur_align:=align_head; cur_loop:=null; scanner_status:=aligning;
warning_index:=save_cs_ptr; align_state:=-1000000;
  {at this point, |cur_cmd=left_brace|}
loop@+  begin @<Append the current tabskip glue to the preamble list@>;
  if cur_cmd=car_ret then goto done; {\.{\\cr} ends the preamble}
  @<Scan preamble text until |cur_cmd| is |tab_mark| or |car_ret|,
    looking for changes in the tabskip glue; append an
    alignrecord to the preamble list@>;
  end;
done: scanner_status:=normal

@ @<Append the current tabskip glue to the preamble list@>=
r:=new_param_glue(tab_skip_code); vlink(cur_align):=r;
cur_align:=vlink(cur_align)

@ @<Scan preamble text until |cur_cmd| is |tab_mark| or |car_ret|...@>=
@<Scan the template \<u_j>, putting the resulting token list in |hold_token_head|@>;
r:=new_node(align_record_node,0); vlink(cur_align):=r;
cur_align:=vlink(cur_align); {a new alignrecord}
span_ptr(cur_align):=end_span; width(cur_align):=null_flag;
u_part(cur_align):=link(hold_token_head);
@<Scan the template \<v_j>, putting the resulting token list in |hold_token_head|@>;
v_part(cur_align):=link(hold_token_head)

@ We enter `\.{\\span}' into |eqtb| with |tab_mark| as its command code,
and with |span_code| as the command modifier. This makes \TeX\ interpret it
essentially the same as an alignment delimiter like `\.\&', yet it is
recognizably different when we need to distinguish it from a normal delimiter.
It also turns out to be useful to give a special |cr_code| to `\.{\\cr}',
and an even larger |cr_cr_code| to `\.{\\crcr}'.

The end of a template is represented by two ``frozen'' control sequences
called \.{\\endtemplate}. The first has the command code |end_template|, which
is |>outer_call|, so it will not easily disappear in the presence of errors.
The |get_x_token| routine converts the first into the second, which has |endv|
as its command code.

@d span_code=special_char {distinct from any character}
@d cr_code=span_code+1 {distinct from |span_code| and from any character}
@d cr_cr_code=cr_code+1 {this distinguishes \.{\\crcr} from \.{\\cr}}
@d end_template_token==cs_token_flag+frozen_end_template

@<Put each of \TeX's primitives into the hash table@>=
primitive_tex("span",tab_mark,span_code,span_code);@/
@!@:span_}{\.{\\span} primitive@>
primitive_tex("cr",car_ret,cr_code,cr_code);
@!@:cr_}{\.{\\cr} primitive@>
text(frozen_cr):="cr"; eqtb[frozen_cr]:=eqtb[cur_val];@/
primitive_tex("crcr",car_ret,cr_cr_code,cr_code);
@!@:cr_cr_}{\.{\\crcr} primitive@>
text(frozen_end_template):="endtemplate"; text(frozen_endv):="endtemplate";
eq_type(frozen_endv):=endv; equiv(frozen_endv):=null_list;
eq_level(frozen_endv):=level_one;@/
eqtb[frozen_end_template]:=eqtb[frozen_endv];
eq_type(frozen_end_template):=end_template;

@ The preamble is copied directly, except that \.{\\tabskip} causes a change
to the tabskip glue, thereby possibly expanding macros that immediately
follow it. An appearance of \.{\\span} also causes such an expansion.

Note that if the preamble contains `\.{\\global\\tabskip}', the `\.{\\global}'
token survives in the preamble and the `\.{\\tabskip}' defines new
tabskip glue (locally).

@<Declare the procedure called |get_preamble_token|@>=
procedure get_preamble_token;
label restart;
begin restart: get_token;
while (cur_chr=span_code)and(cur_cmd=tab_mark) do
  begin get_token; {this token will be expanded once}
  if cur_cmd>max_command then
    begin expand; get_token;
    end;
  end;
if cur_cmd=endv then
  fatal_error("(interwoven alignment preambles are not allowed)");
@.interwoven alignment preambles...@>
if (cur_cmd=assign_glue)and(cur_chr=glue_base+tab_skip_code) then
  begin scan_optional_equals; scan_glue(glue_val);
  if global_defs>0 then geq_define(glue_base+tab_skip_code,glue_ref,cur_val)
  else eq_define(glue_base+tab_skip_code,glue_ref,cur_val);
  goto restart;
  end;
end;

@ Spaces are eliminated from the beginning of a template.

@<Scan the template \<u_j>...@>=
p:=hold_token_head; link(p):=null;
loop@+  begin get_preamble_token;
  if cur_cmd=mac_param then goto done1;
  if (cur_cmd<=car_ret)and(cur_cmd>=tab_mark)and(align_state=-1000000) then
   if (p=hold_token_head)and(cur_loop=null)and(cur_cmd=tab_mark)
    then cur_loop:=cur_align
   else  begin print_err("Missing # inserted in alignment preamble");
@.Missing \# inserted...@>
    help3("There should be exactly one # between &'s, when an")@/
    ("\halign or \valign is being set up. In this case you had")@/
    ("none, so I've put one in; maybe that will work.");
    back_error; goto done1;
    end
  else if (cur_cmd<>spacer)or(p<>hold_token_head) then
    begin r:=get_avail; link(p):=r; p:=link(p); info(p):=cur_tok;
    end;
  end;
done1:

@ @<Scan the template \<v_j>...@>=
p:=hold_token_head; link(p):=null;
loop@+  begin continue: get_preamble_token;
  if (cur_cmd<=car_ret)and(cur_cmd>=tab_mark)and(align_state=-1000000) then
    goto done2;
  if cur_cmd=mac_param then
    begin print_err("Only one # is allowed per tab");
@.Only one \# is allowed...@>
    help3("There should be exactly one # between &'s, when an")@/
    ("\halign or \valign is being set up. In this case you had")@/
    ("more than one, so I'm ignoring all but the first.");
    error; goto continue;
    end;
  r:=get_avail; link(p):=r; p:=link(p); info(p):=cur_tok;
  end;
done2: r:=get_avail; link(p):=r; p:=link(p);
info(p):=end_template_token {put \.{\\endtemplate} at the end}

@ The tricky part about alignments is getting the templates into the
scanner at the right time, and recovering control when a row or column
is finished.

We usually begin a row after each \.{\\cr} has been sensed, unless that
\.{\\cr} is followed by \.{\\noalign} or by the right brace that terminates
the alignment. The |align_peek| routine is used to look ahead and do
the right thing; it either gets a new row started, or gets a \.{\\noalign}
started, or finishes off the alignment.

@<Declare the procedure called |align_peek|@>=
procedure align_peek;
label restart;
begin restart: align_state:=1000000;
repeat get_x_or_protected;
until cur_cmd<>spacer;
if cur_cmd=no_align then
  begin scan_left_brace; new_save_level(no_align_group);
  if mode=-vmode then normal_paragraph;
  end
else if cur_cmd=right_brace then fin_align
else if (cur_cmd=car_ret)and(cur_chr=cr_cr_code) then
  goto restart {ignore \.{\\crcr}}
else  begin init_row; {start a new row}
  init_col; {start a new column and replace what we peeked at}
  end;
end;

@ To start a row (i.e., a `row' that rhymes with `dough' but not with `bough'),
we enter a new semantic level, copy the first tabskip glue, and change
from internal vertical mode to restricted horizontal mode or vice versa.
The |space_factor| and |prev_depth| are not used on this semantic level,
but we clear them to zero just to be tidy.

@p @t\4@>@<Declare the procedure called |init_span|@>@t@>@/
procedure init_row;
begin push_nest; mode:=(-hmode-vmode)-mode;
if mode=-hmode then space_factor:=0 @+else prev_depth:=0;
tail_append(new_glue(glue_ptr(preamble)));
subtype(tail):=tab_skip_code+1;@/
cur_align:=vlink(preamble); cur_tail:=cur_head; cur_pre_tail:=cur_pre_head;
init_span(cur_align);
end;

@ The parameter to |init_span| is a pointer to the alignrecord where the
next column or group of columns will begin. A new semantic level is
entered, so that the columns will generate a list for subsequent packaging.

@<Declare the procedure called |init_span|@>=
procedure init_span(@!p:pointer);
begin push_nest;
if mode=-hmode then space_factor:=1000
else  begin prev_depth:=pdf_ignored_dimen; normal_paragraph;
  end;
cur_span:=p;
end;

@ When a column begins, we assume that |cur_cmd| is either |omit| or else
the current token should be put back into the input until the \<u_j>
template has been scanned.  (Note that |cur_cmd| might be |tab_mark| or
|car_ret|.)  We also assume that |align_state| is approximately 1000000 at
this time.  We remain in the same mode, and start the template if it is
called for.

@p procedure init_col;
begin extra_info(cur_align):=cur_cmd;
if cur_cmd=omit then align_state:=0
else  begin back_input; begin_token_list(u_part(cur_align),u_template);
  end; {now |align_state=1000000|}
end;

@ The scanner sets |align_state| to zero when the \<u_j> template ends. When
a subsequent \.{\\cr} or \.{\\span} or tab mark occurs with |align_state=0|,
the scanner activates the following code, which fires up the \<v_j> template.
We need to remember the |cur_chr|, which is either |cr_cr_code|, |cr_code|,
|span_code|, or a character code, depending on how the column text has ended.

This part of the program had better not be activated when the preamble
to another alignment is being scanned, or when no alignment preamble is active.

@p procedure insert_vj_template;
begin if (scanner_status=aligning) or (cur_align=null) then
  fatal_error("(interwoven alignment preambles are not allowed)");
@.interwoven alignment preambles...@>
cur_cmd:=extra_info(cur_align); extra_info(cur_align):=cur_chr;
if cur_cmd=omit then begin_token_list(omit_template,v_template)
else begin_token_list(v_part(cur_align),v_template);
align_state:=1000000;
end;

@ The token list |omit_template| just referred to is a constant token
list that contains the special control sequence \.{\\endtemplate} only.

@<Initialize the special...@>=
info(omit_template):=end_template_token; {|link(omit_template)=null|}

@ When the |endv| command at the end of a \<v_j> template comes through the
scanner, things really start to happen; and it is the |fin_col| routine
that makes them happen. This routine returns |true| if a row as well as a
column has been finished.

@p function fin_col:boolean;
label exit;
var p:pointer; {the alignrecord after the current one}
@!q,@!r:pointer; {temporary pointers for list manipulation}
@!s:pointer; {a new span node}
@!u:pointer; {a new unset box}
@!w:scaled; {natural width}
@!o:glue_ord; {order of infinity}
@!n:halfword; {span counter}
begin if cur_align=null then confusion("endv");
q:=vlink(cur_align);@+if q=null then confusion("endv");
@:this can't happen endv}{\quad endv@>
if align_state<500000 then
  fatal_error("(interwoven alignment preambles are not allowed)");
@.interwoven alignment preambles...@>
p:=vlink(q);
@<If the preamble list has been traversed, check that the row has ended@>;
if extra_info(cur_align)<>span_code then
  begin unsave; new_save_level(align_group);@/
  @<Package an unset box for the current column and record its width@>;
  @<Copy the tabskip glue between columns@>;
  if extra_info(cur_align)>=cr_code then
    begin fin_col:=true; return;
    end;
  init_span(p);
  end;
align_state:=1000000;
repeat get_x_or_protected;
until cur_cmd<>spacer;
cur_align:=p;
init_col; fin_col:=false;
exit: end;

@ @<If the preamble list has been traversed, check that the row has ended@>=
if (p=null)and(extra_info(cur_align)<cr_code) then begin
 if cur_loop<>null then @<Lengthen the preamble periodically@>
 else  begin print_err("Extra alignment tab has been changed to ");
@.Extra alignment tab...@>
  print_esc("cr");
  help3("You have given more \span or & marks than there were")@/
  ("in the preamble to the \halign or \valign now in progress.")@/
  ("So I'll assume that you meant to type \cr instead.");
  extra_info(cur_align):=cr_code; error;
  end;
end

@ @<Lengthen the preamble...@>=
begin r:=new_node(align_record_node,0); vlink(q):=r; p:=vlink(q); {a new alignrecord}
span_ptr(p):=end_span; width(p):=null_flag; cur_loop:=vlink(cur_loop);
@<Copy the templates from node |cur_loop| into node |p|@>;
cur_loop:=vlink(cur_loop);
r:=new_glue(glue_ptr(cur_loop)); vlink(p):=r;
end

@ @<Copy the templates from node |cur_loop| into node |p|@>=
q:=hold_token_head; r:=u_part(cur_loop);
while r<>null do
  begin s:=get_avail; link(q):=s; q:=link(q); info(q):=info(r); r:=link(r);
  end;
link(q):=null; u_part(p):=link(hold_token_head);
q:=hold_token_head; r:=v_part(cur_loop);
while r<>null do
  begin s:=get_avail; link(q):=s; q:=link(q); info(q):=info(r); r:=link(r);
  end;
link(q):=null; v_part(p):=link(hold_token_head)

@ @<Copy the tabskip glue...@>=
tail_append(new_glue(glue_ptr(vlink(cur_align))));
subtype(tail):=tab_skip_code+1

@ @<Package an unset...@>=
begin if mode=-hmode then
  begin adjust_tail:=cur_tail; pre_adjust_tail:=cur_pre_tail;
  u:=filtered_hpack(head,tail,natural,align_set_group); w:=width(u);
  cur_tail:=adjust_tail; adjust_tail:=null;
  cur_pre_tail:=pre_adjust_tail; pre_adjust_tail:=null;
  end
else  begin u:=filtered_vpackage(vlink(head),natural,0,align_set_group); w:=height(u);
  end;
n:=min_quarterword; {this represents a span count of 1}
if cur_span<>cur_align then @<Update width entry for spanned columns@>
else if w>width(cur_align) then width(cur_align):=w;
type(u):=unset_node; span_count(u):=n;@/
@<Determine the stretch order@>;
glue_order(u):=o; glue_stretch(u):=total_stretch[o];@/
@<Determine the shrink order@>;
glue_sign(u):=o; glue_shrink(u):=total_shrink[o];@/
pop_nest; vlink(tail):=u; tail:=u;
end

@ A span node is a 3-word record containing |width|, |span_span|, and
|span_ptr| fields. The |span_span| field indicates the number of
spanned columns; the |span_ptr| field points to a span node for the same
starting column, having a greater extent of spanning, or to
|end_span|, which has the largest possible |span_span| field; the |width|
field holds the largest natural width corresponding to a particular
set of spanned columns.

A list of the maximum widths so far, for spanned columns starting at a
given column, begins with the |span_ptr| field of the alignrecord for
that column. The code has to make sure that there is room for
|span_ptr| in both the alignrecord and the span nodes, which is why
|span_ptr| replaces |node_attr|.
@^data structure assumptions@>

The |new_span_node| function is defined in |texnodes.c|.

@d span_span(#)==vlink(#+1) {that is normally |alink| }

@<Initialize the special list heads...@>=
span_span(end_span):=max_quarterword+1; span_ptr(end_span):=null;

@ @<Update width entry for spanned columns@>=
begin q:=cur_span;
repeat incr(n); q:=vlink(vlink(q));
until q=cur_align;
if n>max_quarterword then confusion("too many spans"); {this can happen, but won't}
@^system dependencies@>
@:this can't happen too many spans}{\quad too many spans@>
q:=cur_span;
while span_span(span_ptr(q))<n do begin
  q:=span_ptr(q);
  end;
if span_span(span_ptr(q))>n then begin
  s:=new_span_node(span_ptr(q),n,w);
  span_ptr(q):=s;
  end
else if width(span_ptr(q))<w then width(span_ptr(q)):=w;
end

@ At the end of a row, we append an unset box to the current vlist (for
\.{\\halign}) or the current hlist (for \.{\\valign}). This unset box
contains the unset boxes for the columns, separated by the tabskip glue.
Everything will be set later.

@p procedure fin_row;
var p:pointer; {the new unset box}
begin if mode=-hmode then
  begin p:=filtered_hpack(head,tail,natural,fin_row_group);
  pop_nest;
  if cur_pre_head <> cur_pre_tail then
      append_list(cur_pre_head)(cur_pre_tail);
  append_to_vlist(p);
  if cur_head <> cur_tail then
      append_list(cur_head)(cur_tail);
  end
else  begin p:=filtered_vpackage(vlink(head),natural,max_depth,fin_row_group);
  pop_nest; vlink(tail):=p; tail:=p; space_factor:=1000;
  end;
type(p):=unset_node; glue_stretch(p):=0;
if every_cr<>null then begin_token_list(every_cr,every_cr_text);
align_peek;
end; {note that |glue_shrink(p)=0| since |glue_shrink==shift_amount|}

@ Finally, we will reach the end of the alignment, and we can breathe a
sigh of relief that memory hasn't overflowed. All the unset boxes will now be
set so that the columns line up, taking due account of spanned columns.

@p procedure@?do_assignments; forward;@t\2@>@/
procedure@?resume_after_display; forward;@t\2@>@/
procedure@?build_page; forward;@t\2@>@/
procedure fin_align;
var @!p,@!q,@!r,@!s,@!u,@!v,@!rr: pointer; {registers for the list operations}
@!t,@!w:scaled; {width of column}
@!o:scaled; {shift offset for unset boxes}
@!n:halfword; {matching span amount}
@!rule_save:scaled; {temporary storage for |overfull_rule|}
@!aux_save:memory_word; {temporary storage for |aux|}
begin if cur_group<>align_group then confusion("align1");
@:this can't happen align}{\quad align@>
unsave; {that |align_group| was for individual entries}
if cur_group<>align_group then confusion("align0");
unsave; {that |align_group| was for the whole alignment}
if nest[nest_ptr-1].mode_field=mmode then o:=display_indent
  else o:=0;
@<Go through the preamble list, determining the column widths and
  changing the alignrecords to dummy unset boxes@>;
@<Package the preamble list, to determine the actual tabskip glue amounts,
  and let |p| point to this prototype box@>;
@<Set the glue in all the unset boxes of the current list@>;
flush_node_list(p); pop_alignment;
@<Insert the \(c)current list into its environment@>;
end;@/
@t\4@>@<Declare the procedure called |align_peek|@>

@ It's time now to dismantle the preamble list and to compute the column
widths. Let $w_{ij}$ be the maximum of the natural widths of all entries
that span columns $i$ through $j$, inclusive. The alignrecord for column~$i$
contains $w_{ii}$ in its |width| field, and there is also a linked list of
the nonzero $w_{ij}$ for increasing $j$, accessible via the |info| field;
these span nodes contain the value $j-i+|min_quarterword|$ in their
|link| fields. The values of $w_{ii}$ were initialized to |null_flag|, which
we regard as $-\infty$.

The final column widths are defined by the formula
$$w_j=\max_{1\L i\L j}\biggl( w_{ij}-\sum_{i\L k<j}(t_k+w_k)\biggr),$$
where $t_k$ is the natural width of the tabskip glue between columns
$k$ and~$k+1$. However, if $w_{ij}=-\infty$ for all |i| in the range
|1<=i<=j| (i.e., if every entry that involved column~|j| also involved
column~|j+1|), we let $w_j=0$, and we zero out the tabskip glue after
column~|j|.

\TeX\ computes these values by using the following scheme: First $w_1=w_{11}$.
Then replace $w_{2j}$ by $\max(w_{2j},w_{1j}-t_1-w_1)$, for all $j>1$.
Then $w_2=w_{22}$. Then replace $w_{3j}$ by $\max(w_{3j},w_{2j}-t_2-w_2)$
for all $j>2$; and so on. If any $w_j$ turns out to be $-\infty$, its
value is changed to zero and so is the next tabskip.

@<Go through the preamble list,...@>=
q:=vlink(preamble);
repeat flush_list(u_part(q)); flush_list(v_part(q));
p:=vlink(vlink(q));
if width(q)=null_flag then
  @<Nullify |width(q)| and the tabskip glue following this column@>;
if span_ptr(q)<>end_span then
  @<Merge the widths in the span nodes of |q| with those of |p|,
    destroying the span nodes of |q|@>;
type(q):=unset_node; span_count(q):=min_quarterword; height(q):=0;
depth(q):=0; glue_order(q):=normal; glue_sign(q):=normal;
glue_stretch(q):=0; glue_shrink(q):=0; q:=p;
until q=null

@ @<Nullify |width(q)| and the tabskip glue following this column@>=
begin width(q):=0; r:=vlink(q); s:=glue_ptr(r);
if s<>zero_glue then
  begin add_glue_ref(zero_glue); delete_glue_ref(s);
  glue_ptr(r):=zero_glue;
  end;
end

@ Merging of two span-node lists is a typical exercise in the manipulation of
linearly linked data structures. The essential invariant in the following
|repeat| loop is that we want to dispense with node |r|, in |q|'s list,
and |u| is its successor; all nodes of |p|'s list up to and including |s|
have been processed, and the successor of |s| matches |r| or precedes |r|
or follows |r|, according as |link(r)=n| or |link(r)>n| or |link(r)<n|.

@<Merge the widths...@>=
begin t:=width(q)+width(glue_ptr(vlink(q)));
r:=span_ptr(q); s:=end_span; span_ptr(s):=p; n:=min_quarterword+1;
repeat width(r):=width(r)-t; u:=span_ptr(r);
while span_span(r)>n do
  begin s:=span_ptr(s); n:=span_span(span_ptr(s))+1;
  end;
if span_span(r)<n then
  begin span_ptr(r):=span_ptr(s); span_ptr(s):=r; decr(span_span(r)); s:=r;
  end
else  begin if width(r)>width(span_ptr(s)) then width(span_ptr(s)):=width(r);
  flush_node(r);
  end;
r:=u;
until r=end_span;
end

@ Now the preamble list has been converted to a list of alternating unset
boxes and tabskip glue, where the box widths are equal to the final
column sizes. In case of \.{\\valign}, we change the widths to heights,
so that a correct error message will be produced if the alignment is
overfull or underfull.

@<Package the preamble list...@>=
save_ptr:=save_ptr-2; pack_begin_line:=-mode_line;
if mode=-vmode then
  begin rule_save:=overfull_rule;
  overfull_rule:=0; {prevent rule from being packaged}
  p:=hpack(preamble,saved(1),saved(0));
  overfull_rule:=rule_save;
  end
else  begin q:=vlink(preamble);
  repeat height(q):=width(q); width(q):=0; q:=vlink(vlink(q));
  until q=null;
  p:=filtered_vpackage(preamble,saved(1),saved(0),max_depth,preamble_group);
  q:=vlink(preamble);
  repeat width(q):=height(q); height(q):=0; q:=vlink(vlink(q));
  until q=null;
  end;
pack_begin_line:=0

@ @<Set the glue in all the unset...@>=
q:=vlink(head); s:=head;
while q<>null do
  begin if not is_char_node(q) then begin
    if type(q)=unset_node then
      @<Set the unset box |q| and the unset boxes in it@>
    else if type(q)=rule_node then
      @<Make the running dimensions in rule |q| extend to the
        boundaries of the alignment@>;
    end;
  s:=q; q:=vlink(q);
  end

@ @<Make the running dimensions in rule |q| extend...@>=
begin if is_running(width(q)) then width(q):=width(p);
if is_running(height(q)) then height(q):=height(p);
if is_running(depth(q)) then depth(q):=depth(p);
if o<>0 then
  begin r:=vlink(q); vlink(q):=null; q:=hpack(q,natural);
  shift_amount(q):=o; vlink(q):=r; vlink(s):=q;
  end;
end

@ The unset box |q| represents a row that contains one or more unset boxes,
depending on how soon \.{\\cr} occurred in that row.

@<Set the unset box |q| and the unset boxes in it@>=
begin if mode=-vmode then
  begin type(q):=hlist_node; width(q):=width(p);
  end
else  begin type(q):=vlist_node; height(q):=height(p);
  end;
glue_order(q):=glue_order(p); glue_sign(q):=glue_sign(p);
glue_set(q):=glue_set(p); shift_amount(q):=o;
r:=vlink(list_ptr(q)); s:=vlink(list_ptr(p));
repeat @<Set the glue in node |r| and change it from an unset node@>;
r:=vlink(vlink(r)); s:=vlink(vlink(s));
until r=null;
end

@ A box made from spanned columns will be followed by tabskip glue nodes and
by empty boxes as if there were no spanning. This permits perfect alignment
of subsequent entries, and it prevents values that depend on floating point
arithmetic from entering into the dimensions of any boxes.

@<Set the glue in node |r|...@>=
n:=span_count(r); t:=width(s); w:=t; u:=hold_head;
while n>min_quarterword do
  begin decr(n);
  @<Append tabskip glue and an empty box to list |u|,
    and update |s| and |t| as the prototype nodes are passed@>;
  end;
if mode=-vmode then
  @<Make the unset node |r| into an |hlist_node| of width |w|,
    setting the glue as if the width were |t|@>
else @<Make the unset node |r| into a |vlist_node| of height |w|,
    setting the glue as if the height were |t|@>;
shift_amount(r):=0;
if u<>hold_head then {append blank boxes to account for spanned nodes}
  begin vlink(u):=vlink(r); vlink(r):=vlink(hold_head); r:=u;
  end

@ @<Append tabskip glue and an empty box to list |u|...@>=
s:=vlink(s); v:=glue_ptr(s); vlink(u):=new_glue(v); u:=vlink(u);
subtype(u):=tab_skip_code+1; t:=t+width(v);
if glue_sign(p)=stretching then
  begin if stretch_order(v)=glue_order(p) then
    t:=t+round(float(glue_set(p))*stretch(v));
@^real multiplication@>
  end
else if glue_sign(p)=shrinking then
  begin if shrink_order(v)=glue_order(p) then
    t:=t-round(float(glue_set(p))*shrink(v));
  end;
s:=vlink(s); rr:=new_null_box; vlink(u):=rr; u:=vlink(u); t:=t+width(s);
if mode=-vmode then width(u):=width(s)@+else
  begin type(u):=vlist_node; height(u):=width(s);
  end

@ @<Make the unset node |r| into an |hlist_node| of width |w|...@>=
begin height(r):=height(q); depth(r):=depth(q);
if t=width(r) then
  begin glue_sign(r):=normal; glue_order(r):=normal;
  set_glue_ratio_zero(glue_set(r));
  end
else if t>width(r) then
  begin glue_sign(r):=stretching;
  if glue_stretch(r)=0 then set_glue_ratio_zero(glue_set(r))
  else glue_set(r):=unfloat((t-width(r))/glue_stretch(r));
@^real division@>
  end
else  begin glue_order(r):=glue_sign(r); glue_sign(r):=shrinking;
  if glue_shrink(r)=0 then set_glue_ratio_zero(glue_set(r))
  else if (glue_order(r)=normal)and(width(r)-t>glue_shrink(r)) then
    set_glue_ratio_one(glue_set(r))
  else glue_set(r):=unfloat((width(r)-t)/glue_shrink(r));
  end;
width(r):=w; type(r):=hlist_node;
end

@ @<Make the unset node |r| into a |vlist_node| of height |w|...@>=
begin width(r):=width(q);
if t=height(r) then
  begin glue_sign(r):=normal; glue_order(r):=normal;
  set_glue_ratio_zero(glue_set(r));
  end
else if t>height(r) then
  begin glue_sign(r):=stretching;
  if glue_stretch(r)=0 then set_glue_ratio_zero(glue_set(r))
  else glue_set(r):=unfloat((t-height(r))/glue_stretch(r));
@^real division@>
  end
else  begin glue_order(r):=glue_sign(r); glue_sign(r):=shrinking;
  if glue_shrink(r)=0 then set_glue_ratio_zero(glue_set(r))
  else if (glue_order(r)=normal)and(height(r)-t>glue_shrink(r)) then
    set_glue_ratio_one(glue_set(r))
  else glue_set(r):=unfloat((height(r)-t)/glue_shrink(r));
  end;
height(r):=w; type(r):=vlist_node;
end

@ We now have a completed alignment, in the list that starts at |head|
and ends at |tail|. This list will be merged with the one that encloses
it. (In case the enclosing mode is |mmode|, for displayed formulas,
we will need to insert glue before and after the display; that part of the
program will be deferred until we're more familiar with such operations.)

@<Insert the \(c)current list into its environment@>=
aux_save:=aux; p:=vlink(head); q:=tail; pop_nest;
if mode=mmode then finish_display_alignment(p,q,aux_save)
else  begin aux:=aux_save; vlink(tail):=p;
  if p<>null then tail:=q;
  if mode=vmode then begin check_filter('alignment'); build_page; end;
  end

@* \[38] Breaking paragraphs into lines.
We come now to what is probably the most interesting algorithm of \TeX:
the mechanism for choosing the ``best possible'' breakpoints that yield
the individual lines of a paragraph. \TeX's line-breaking algorithm takes
a given horizontal list and converts it to a sequence of boxes that are
appended to the current vertical list. In the course of doing this, it
creates a special data structure containing three kinds of records that are
not used elsewhere in \TeX. Such nodes are created while a paragraph is
being processed, and they are destroyed afterwards; thus, the other parts
of \TeX\ do not need to know anything about how line-breaking is done.

The method used here is based on an approach devised by Michael F. Plass and
@^Plass, Michael Frederick@>
@^Knuth, Donald Ervin@>
the author in 1977, subsequently generalized and improved by the same two
people in 1980. A detailed discussion appears in {\sl SOFTWARE---Practice
\AM\ Experience \bf11} (1981), 1119--1184, where it is shown that the
line-breaking problem can be regarded as a special case of the problem of
computing the shortest path in an acyclic network. The cited paper includes
numerous examples and describes the history of line breaking as it has been
practiced by printers through the ages. The present implementation adds two
new ideas to the algorithm of 1980: Memory space requirements are considerably
reduced by using smaller records for inactive nodes than for active ones,
and arithmetic overflow is avoided by using ``delta distances'' instead of
keeping track of the total distance from the beginning of the paragraph to the
current point.

@ The |line_break| procedure should be invoked only in horizontal mode; it
leaves that mode and places its output into the current vlist of the
enclosing vertical mode (or internal vertical mode).
There is one explicit parameter:  |d| is true for partial paragraphs
preceding display math mode; in this case the amount of additional
penalty inserted before the final line is |display_widow_penalty|
instead of |widow_penalty|.

There are also a number of implicit parameters: The hlist to be broken
starts at |vlink(head)|, and it is nonempty. The value of |prev_graf| in the
enclosing semantic level tells where the paragraph should begin in the
sequence of line numbers, in case hanging indentation or \.{\\parshape}
are in use; |prev_graf| is zero unless this paragraph is being continued
after a displayed formula.  Other implicit parameters, such as the
|par_shape_ptr| and various penalties to use for hyphenation, etc., appear
in |eqtb|.

After |line_break| has acted, it will have updated the current vlist and the
value of |prev_graf|. Furthermore, the global variable |just_box| will
point to the final box created by |line_break|, so that the width of this
line can be ascertained when it is necessary to decide whether to use
|above_display_skip| or |above_display_short_skip| before a displayed formula.

@<Glob...@>=
@!just_box:pointer; {the |hlist_node| for the last line of the new paragraph}
@!paragraph_dir:integer; {main direction of paragraph}
@!line_break_dir:integer; {current direction within paragraph}
@!line_break_context:integer; {the surrounding state for |line_break| calls}
@!break_c_htdp:quarterword; {height-depth entry in |char_info|}
@!temp_no_whatsits:integer; {used when closing group}
@!temp_no_dirs:integer; {used when closing group}
@!temporary_dir:integer;
@!dir_ptr,@!dir_tmp,@!dir_rover:pointer;

@ @<Set init...@>=
temp_no_whatsits:=0; temp_no_dirs:=0; temporary_dir:=0;
dir_ptr:=null; dir_tmp:=null; dir_rover:=null;
line_break_context := bottom_level;

@ In it's complete form, |line_break| is a rather lengthy
procedure---sort of a small world unto itself---we must build it up
little by little. Below you see only the general outline.

The main task performed here is to move the list from |head| to
|temp_head| and go into the enclosing semantic level. We also append
the \.{\\parfillskip} glue to the end of the paragraph, removing a
space (or other glue node) if it was there, since spaces usually
precede blank lines and instances of `\.{\$\$}'. The |par_fill_skip|
is preceded by an infinite penalty, so it will never be considered as
a potential breakpoint.

That code assumes that a |glue_node| and a |penalty_node| occupy the
same number of |mem|~words.
@^data structure assumptions@>

Most other processing is delegated to external functions.

@p procedure line_break(@!d:boolean);
var final_par_glue:pointer;
start_of_par:pointer;
callback_id:integer;
begin pack_begin_line:=mode_line; {this is for over/underfull box messages}
vlink(temp_head):=vlink(head);
new_hyphenation(temp_head, tail);
if (not is_char_node(vlink(head))) and ((type(vlink(head))=whatsit_node)
   and (subtype(vlink(head))=local_par_node)) then
  paragraph_dir:=local_par_dir(vlink(head))
else
  paragraph_dir:=0;
line_break_dir:=paragraph_dir;
tail:=new_ligkern(temp_head,tail);
if is_char_node(tail) then new_tail_append(new_penalty(inf_penalty))
else if type(tail)<>glue_node then new_tail_append(new_penalty(inf_penalty))
else begin
  type(tail):=penalty_node;
  delete_glue_ref(glue_ptr(tail));
  if leader_ptr(tail)<>null then
    flush_node_list(leader_ptr(tail));
  penalty(tail):=inf_penalty;
  end;
final_par_glue:=new_param_glue(par_fill_skip_code);
couple_nodes(tail,final_par_glue);
lua_node_filter(pre_linebreak_filter_callback,
      line_break_context,temp_head,addressof(tail));
last_line_fill:=vlink(tail);
pop_nest;
start_of_par:=tail;
callback_id:=callback_defined(linebreak_filter_callback);
if callback_id>0 then begin
  callback_id := lua_linebreak_callback(d, temp_head, addressof(tail));
  if callback_id>0 then begin
    just_box := tail;
    if just_box<>null then
      while vlink(just_box)<>null do
         just_box := vlink(just_box);
    if (just_box=null)or(type(just_box) <> hlist_node) then begin
      help3("A linebreaking routine should return a non-empty list of nodes")
           ("and the last one of those has to be a \\hbox.")
           ("Sorry, I cannot recover from this.");
      print_err("Invalid linebreak_filter");
      succumb;
      end
    end
  else begin
    if tracing_paragraphs>0 then begin
      begin_diagnostic;
      print_nl("Lua linebreak_filter failed, reverting to default on line "); print_int(line);
      end_diagnostic(true);
    end;
  end;
end;
if callback_id=0 then begin
  ext_do_line_break(d,pretolerance,tracing_paragraphs,tolerance,emergency_stretch,
                   looseness,hyphen_penalty,ex_hyphen_penalty,
                   pdf_adjust_spacing, par_shape_ptr, adj_demerits,
                   pdf_protrude_chars, line_penalty, last_line_fit,
                   double_hyphen_demerits, final_hyphen_demerits,
                   hang_indent, hsize, hang_after, left_skip, right_skip,
                   pdf_each_line_height,pdf_each_line_depth,
                   pdf_first_line_height, pdf_last_line_depth,
                   inter_line_penalties_ptr, inter_line_penalty,
                   club_penalty, club_penalties_ptr,
                   display_widow_penalties_ptr,widow_penalties_ptr,
                   display_widow_penalty, widow_penalty,
                   broken_penalty, final_par_glue, pdf_ignored_dimen);
end;
lua_node_filter(post_linebreak_filter_callback,
      line_break_context,start_of_par,addressof(tail));
pack_begin_line:=0;
end;
@#
@t\4@>@<Declare \eTeX\ procedures for use by |main_control|@>

@ It is possible that the user wants to interfere at some point.

The choice between |check_head_filter| and |check_contrib_filter| is not
quite clear to me yet, but it seems that the latter is the better choice.

@d check_filter(#)==if not output_active then lua_node_filter_s(buildpage_filter_callback,#)

@* \[39] Breaking paragraphs into lines, continued.

Hyphenation and line breaking are now all handled in C. Only the
section heads are kept here.

@* \[40] Pre-hyphenation.

@* \[41] Post-hyphenation.

@* \[42] Hyphenation.

@ When \TeX\ has scanned `\.{\\hyphenation}', it calls on a procedure named
|new_hyph_exceptions| to do the right thing.

@p procedure new_hyph_exceptions; {enters new exceptions}
var p:halfword; {just to catch the return value of |scan_toks|}
begin p:=scan_toks(false,true);
load_tex_hyphenation(language,def_ref);
flush_list(def_ref);
end;

@ Similarly, when \TeX\ has scanned `\.{\\patterns}', it calls on a
procedure named |new_patterns|.

@p procedure new_patterns; {initializes the hyphenation pattern data}
var p:halfword; {just to catch the return value of |scan_toks|}
begin p:=scan_toks(false,true);
load_tex_patterns(language,def_ref);
flush_list(def_ref);
end;

@ `\.{\\prehyphenchar}', sets the |pre_break| character, and
`\.{\\posthyphenchar}' the |post_break| character. Their respective
defaults are ascii hyphen ("-") and zero (nul).

@p procedure new_pre_hyphen_char;
begin scan_optional_equals; scan_int;
   set_pre_hyphen_char(language,cur_val);
end;
@#
procedure new_post_hyphen_char;
begin scan_optional_equals; scan_int;
   set_post_hyphen_char(language,cur_val);
end;

@ `\.{\\preexhyphenchar}', sets the |pre_break| character, and
`\.{\\postexhyphenchar}' the |post_break| character. Their
defaults are both zero (nul).

@p procedure new_pre_exhyphen_char;
begin scan_optional_equals; scan_int;
   set_pre_exhyphen_char(language,cur_val);
end;
@#
procedure new_post_exhyphen_char;
begin scan_optional_equals; scan_int;
   set_post_exhyphen_char(language,cur_val);
end;


@* \[43] Initializing the hyphenation tables.

None of the trie-related stuff is applicable any more in luatex.

@* \[44] Breaking vertical lists into pages.
The |vsplit| procedure, which implements \TeX's \.{\\vsplit} operation,
is considerably simpler than |line_break| because it doesn't have to
worry about hyphenation, and because its mission is to discover a single
break instead of an optimum sequence of breakpoints.  But before we get
into the details of |vsplit|, we need to consider a few more basic things.

@ A subroutine called |prune_page_top| takes a pointer to a vlist and
returns a pointer to a modified vlist in which all glue, kern, and penalty nodes
have been deleted before the first box or rule node. However, the first
box or rule is actually preceded by a newly created glue node designed so that
the topmost baseline will be at distance |split_top_skip| from the top,
whenever this is possible without backspacing.

When the second argument |s| is |false| the deleted nodes are destroyed,
otherwise they are collected in a list starting at |split_disc|.

@d discard_or_move = 60
@p function prune_page_top(@!p:pointer;@!s:boolean):pointer;
var prev_p:pointer; {lags one step behind |p|}
@!q,@!r:pointer; {temporary variables for list manipulation}
begin prev_p:=temp_head; vlink(temp_head):=p; r:=null;
while p<>null do
  case type(p) of
  hlist_node_case,vlist_node_case,rule_node_case:@<Insert glue for |split_top_skip|
    and set~|p:=null|@>;
  whatsit_node_case,mark_node_case,ins_node_case: begin
    prev_p:=p; p:=vlink(prev_p);
    end;
  glue_node_case,kern_node_case,penalty_node_case: begin
    q:=p; p:=vlink(q); vlink(q):=null;
    vlink(prev_p):=p;
    if s then
      begin if split_disc=null then split_disc:=q else vlink(r):=q;
      r:=q;
      end
    else flush_node_list(q);
    end;
  othercases confusion("pruning")
@:this can't happen pruning}{\quad pruning@>
  endcases;
prune_page_top:=vlink(temp_head);
end;

@ @<Insert glue for |split_top_skip|...@>=
begin q:=new_skip_param(split_top_skip_code); vlink(prev_p):=q; vlink(q):=p;
  {now |temp_ptr=glue_ptr(q)|}
if width(temp_ptr)>height(p) then width(temp_ptr):=width(temp_ptr)-height(p)
else width(temp_ptr):=0;
p:=null;
end

@ The next subroutine finds the best place to break a given vertical list
so as to obtain a box of height~|h|, with maximum depth~|d|.
A pointer to the beginning of the vertical list is given,
and a pointer to the optimum breakpoint is returned. The list is effectively
followed by a forced break, i.e., a penalty node with the |eject_penalty|;
if the best break occurs at this artificial node, the value |null| is returned.

@<Glob...@>=
@!active_height:array[1..9] of scaled;
  {distance from first active node to~|cur_p|}

@ An array of six |scaled| distances is used to keep track of the height
from the beginning of the list to the current place, just as in |line_break|.
In fact, we use one of the same arrays, only changing its name to reflect
its new significance.

@d do_all_six(#)==#(1);#(2);#(3);#(4);#(5);#(6);#(7)

@d cur_height==active_height[1] {the natural height}
@d set_height_zero(#)==active_height[#]:=0 {initialize the height to zero}
@#
@d update_heights=90 {go here to record glue in the |active_height| table}
@d awful_bad=@'7777777777 { more than a billion demerits }

@p function vert_break(@!p:pointer; @!h,@!d:scaled):pointer;
  {finds optimum page break}
label done,not_found,update_heights;
var prev_p:pointer; {if |p| is a glue node, |type(prev_p)| determines
  whether |p| is a legal breakpoint}
@!q,@!r:pointer; {glue specifications}
@!pi:integer; {penalty value}
@!b:integer; {badness at a trial breakpoint}
@!least_cost:integer; {the smallest badness plus penalties found so far}
@!best_place:pointer; {the most recent break that leads to |least_cost|}
@!prev_dp:scaled; {depth of previous box in the list}
@!t:small_number; {|type| of the node following a kern}
begin prev_p:=p; {an initial glue node is not a legal breakpoint}
least_cost:=awful_bad; do_all_six(set_height_zero); prev_dp:=0;
best_place:=null; pi:=0;
loop@+  begin @<If node |p| is a legal breakpoint, check if this break is
    the best known, and |goto done| if |p| is null or
    if the page-so-far is already too full to accept more stuff@>;
  prev_p:=p; p:=vlink(prev_p);
  end;
done: vert_break:=best_place;
end;

@ A global variable |best_height_plus_depth| will be set to the natural size
of the box that corresponds to the optimum breakpoint found by |vert_break|.
(This value is used by the insertion-splitting algorithm of the page builder.)

@<Glob...@>=
@!best_height_plus_depth:scaled; {height of the best box, without stretching or
  shrinking}

@ A subtle point to be noted here is that the maximum depth~|d| might be
negative, so |cur_height| and |prev_dp| might need to be corrected even
after a glue or kern node.

@<If node |p| is a legal breakpoint, check...@>=
if p=null then pi:=eject_penalty
else  @<Use node |p| to update the current height and depth measurements;
    if this node is not a legal breakpoint, |goto not_found|
    or |update_heights|,
    otherwise set |pi| to the associated penalty at the break@>;
@<Check if node |p| is a new champion breakpoint; then \(go)|goto done|
  if |p| is a forced break or if the page-so-far is already too full@>;
if (type(p)<glue_node)or(type(p)>kern_node) then goto not_found;
update_heights: @<Update the current height and depth measurements with
  respect to a glue or kern node~|p|@>;
not_found: if prev_dp>d then
    begin cur_height:=cur_height+prev_dp-d;
    prev_dp:=d;
    end;

@ @<Use node |p| to update the current height and depth measurements...@>=
case type(p) of
hlist_node_case,vlist_node_case,rule_node_case: begin@t@>@;@/
  cur_height:=cur_height+prev_dp+height(p); prev_dp:=depth(p);
  goto not_found;
  end;
whatsit_node_case:@<Process whatsit |p| in |vert_break| loop, |goto not_found|@>;
glue_node_case: if precedes_break(prev_p) then pi:=0
  else goto update_heights;
kern_node_case: begin if vlink(p)=null then t:=penalty_node
  else t:=type(vlink(p));
  if t=glue_node then pi:=0@+else goto update_heights;
  end;
penalty_node_case: pi:=penalty(p);
mark_node_case,ins_node_case: goto not_found;
othercases confusion("vertbreak")
@:this can't happen vertbreak}{\quad vertbreak@>
endcases

@ @d deplorable==100000 {more than |inf_bad|, but less than |awful_bad|}

@<Check if node |p| is a new champion breakpoint; then \(go)...@>=
if pi<inf_penalty then
  begin @<Compute the badness, |b|, using |awful_bad|
    if the box is too full@>;
  if b<awful_bad then begin
    if pi<=eject_penalty then b:=pi
    else if b<inf_bad then b:=b+pi
      else b:=deplorable;
    end;
  if b<=least_cost then
    begin best_place:=p; least_cost:=b;
    best_height_plus_depth:=cur_height+prev_dp;
    end;
  if (b=awful_bad)or(pi<=eject_penalty) then goto done;
  end

@ @<Compute the badness, |b|, using |awful_bad| if the box is too full@>=
if cur_height<h then
  if (active_height[3]<>0) or (active_height[4]<>0) or
    (active_height[5]<>0) or (active_height[6]<>0) then b:=0
  else b:=badness(h-cur_height,active_height[2])
else if cur_height-h>active_height[7] then b:=awful_bad
else b:=badness(cur_height-h,active_height[7])

@ Vertical lists that are subject to the |vert_break| procedure should not
contain infinite shrinkability, since that would permit any amount of
information to ``fit'' on one page.

@<Update the current height and depth measurements with...@>=
if type(p)=kern_node then q:=p
else  begin q:=glue_ptr(p);
  active_height[2+stretch_order(q)]:=@|
    active_height[2+stretch_order(q)]+stretch(q);@/
  active_height[7]:=active_height[7]+shrink(q);
  if (shrink_order(q)<>normal)and(shrink(q)<>0) then
    begin@t@>@;@/
    print_err("Infinite glue shrinkage found in box being split");@/
@.Infinite glue shrinkage...@>
    help4("The box you are \vsplitting contains some infinitely")@/
      ("shrinkable glue, e.g., `\vss' or `\vskip 0pt minus 1fil'.")@/
      ("Such glue doesn't belong there; but you can safely proceed,")@/
      ("since the offensive shrinkability has been made finite.");
    error; r:=new_spec(q); shrink_order(r):=normal; delete_glue_ref(q);
    glue_ptr(p):=r; q:=r;
    end;
  end;
cur_height:=cur_height+prev_dp+width(q); prev_dp:=0

@ Now we are ready to consider |vsplit| itself. Most of
its work is accomplished by the two subroutines that we have just considered.

Given the number of a vlist box |n|, and given a desired page height |h|,
the |vsplit| function finds the best initial segment of the vlist and
returns a box for a page of height~|h|. The remainder of the vlist, if
any, replaces the original box, after removing glue and penalties and
adjusting for |split_top_skip|. Mark nodes in the split-off box are used to
set the values of |split_first_mark| and |split_bot_mark|; we use the
fact that |split_first_mark(x)=null| if and only if |split_bot_mark(x)=null|.

The original box becomes ``void'' if and only if it has been entirely
extracted.  The extracted box is ``void'' if and only if the original
box was void (or if it was, erroneously, an hlist box).

@p function vsplit(@!n:halfword; @!h:scaled):pointer;
  {extracts a page of height |h| from box |n|}
label exit,done;
var v:pointer; {the box to be split}
vdir:integer; {the direction of the box to be split}
p:pointer; {runs through the vlist}
q:pointer; {points to where the break occurs}
i:halfword; {for traversing marks lists}
begin v:=box(n); vdir:=box_dir(v);
flush_node_list(split_disc); split_disc:=null;
for i:=0 to biggest_used_mark do begin
  delete_split_first_mark(i);
  delete_split_bot_mark(i);
end;
@<Dispense with trivial cases of void or bad boxes@>;
q:=vert_break(list_ptr(v),h,split_max_depth);
@<Look at all the marks in nodes before the break, and set the final
  link to |null| at the break@>;
q:=prune_page_top(q,saving_vdiscards>0);
p:=list_ptr(v); list_ptr(v):=null; flush_node(v);
pack_direction:=vdir;
if q=null then box(n):=null {the |eq_level| of the box stays the same}
else box(n):=filtered_vpackage(q,0,additional,max_depth,split_keep_group);
vsplit:=filtered_vpackage(p,h,exactly,split_max_depth,split_off_group);
exit: end;

@ @<Dispense with trivial cases of void or bad boxes@>=
if v=null then
  begin vsplit:=null; return;
  end;
if type(v)<>vlist_node then
  begin print_err(""); print_esc("vsplit"); print(" needs a ");
  print_esc("vbox");
@:vsplit_}{\.{\\vsplit needs a \\vbox}@>
  help2("The box you are trying to split is an \hbox.")@/
  ("I can't split such a box, so I'll leave it alone.");
  error; vsplit:=null; return;
  end

@ It's possible that the box begins with a penalty node that is the
``best'' break, so we must be careful to handle this special case correctly.

@<Look at all the marks...@>=
p:=list_ptr(v);
if p=q then list_ptr(v):=null
else loop@+begin if type(p)=mark_node then begin
    if split_first_mark(mark_class(p))=null then
      begin split_first_mark(mark_class(p)):=mark_ptr(p);
      split_bot_mark(mark_class(p)):=split_first_mark(mark_class(p));
      token_ref_count(split_first_mark(mark_class(p))):=@|
        token_ref_count(split_first_mark(mark_class(p)))+2;
      end
    else  begin delete_token_ref(split_bot_mark(mark_class(p)));
      split_bot_mark(mark_class(p)):=mark_ptr(p);
      add_token_ref(split_bot_mark(mark_class(p)));
      end;
    end;
  if vlink(p)=q then
    begin vlink(p):=null; goto done;
    end;
  p:=vlink(p);
  end;
done:

@* \[45] The page builder.
When \TeX\ appends new material to its main vlist in vertical mode, it uses
a method something like |vsplit| to decide where a page ends, except that
the calculations are done ``on line'' as new items come in.
The main complication in this process is that insertions must be put
into their boxes and removed from the vlist, in a more-or-less optimum manner.

We shall use the term ``current page'' for that part of the main vlist that
is being considered as a candidate for being broken off and sent to the
user's output routine. The current page starts at |vlink(page_head)|, and
it ends at |page_tail|.  We have |page_head=page_tail| if this list is empty.
@^current page@>

Utter chaos would reign if the user kept changing page specifications
while a page is being constructed, so the page builder keeps the pertinent
specifications frozen as soon as the page receives its first box or
insertion.  The global variable |page_contents| is |empty| when the
current page contains only mark nodes and content-less whatsit nodes; it
is |inserts_only| if the page contains only insertion nodes in addition to
marks and whatsits.  Glue nodes, kern nodes, and penalty nodes are
discarded until a box or rule node appears, at which time |page_contents|
changes to |box_there|.  As soon as |page_contents| becomes non-|empty|,
the current |vsize| and |max_depth| are squirreled away into |page_goal|
and |page_max_depth|; the latter values will be used until the page has
been forwarded to the user's output routine. The \.{\\topskip} adjustment
is made when |page_contents| changes to |box_there|.

Although |page_goal| starts out equal to |vsize|, it is decreased by the
scaled natural height-plus-depth of the insertions considered so far, and by
the \.{\\skip} corrections for those insertions. Therefore it represents
the size into which the non-inserted material should fit, assuming that
all insertions in the current page have been made.

The global variables |best_page_break| and |least_page_cost| correspond
respectively to the local variables |best_place| and |least_cost| in the
|vert_break| routine that we have already studied; i.e., they record the
location and value of the best place currently known for breaking the
current page. The value of |page_goal| at the time of the best break is
stored in |best_size|.

@d inserts_only=1
  {|page_contents| when an insert node has been contributed, but no boxes}
@d box_there=2 {|page_contents| when a box or rule has been contributed}

@<Glob...@>=
@!page_tail:pointer; {the final node on the current page}
@!page_contents:empty..box_there; {what is on the current page so far?}
@!page_max_depth:scaled; {maximum box depth on page being built}
@!best_page_break:pointer; {break here to get the best page known so far}
@!least_page_cost:integer; {the score for this currently best page}
@!best_size:scaled; {its |page_goal|}

@ The page builder has another data structure to keep track of insertions.
This is a list of four-word nodes, starting and ending at |page_ins_head|.
That is, the first element of the list is node |r@t$_1$@>=vlink(page_ins_head)|;
node $r_j$ is followed by |r@t$_{j+1}$@>=vlink(r@t$_j$@>)|; and if there are
|n| items we have |r@t$_{n+1}$@>=page_ins_head|. The |subtype| field of
each node in this list refers to an insertion number; for example, `\.{\\insert
250}' would correspond to a node whose |subtype| is |qi(250)|
(the same as the |subtype| field of the relevant |ins_node|). These |subtype|
fields are in increasing order, and |subtype(page_ins_head)=65535, so
|page_ins_head| serves as a convenient sentinel
at the end of the list. A record is present for each insertion number that
appears in the current page.

The |type| field in these nodes distinguishes two possibilities that
might occur as we look ahead before deciding on the optimum page break.
If |type(r)=inserting_node|, then |height(r)| contains the total of the
height-plus-depth dimensions of the box and all its inserts seen so far.
If |type(r)=split_up_node|, then no more insertions will be made into this box,
because at least one previous insertion was too big to fit on the current
page; |broken_ptr(r)| points to the node where that insertion will be
split, if \TeX\ decides to split it, |broken_ins(r)| points to the
insertion node that was tentatively split, and |height(r)| includes also the
natural height plus depth of the part that would be split off.

In both cases, |last_ins_ptr(r)| points to the last |ins_node|
encountered for box |qo(subtype(r))| that would be at least partially
inserted on the next page; and |best_ins_ptr(r)| points to the last
such |ins_node| that should actually be inserted, to get the page with
minimum badness among all page breaks considered so far. We have
|best_ins_ptr(r)=null| if and only if no insertion for this box should
be made to produce this optimum page.

The data structure definitions here use the fact that the |@!height| field
appears in the fourth word of a box node.
@^data structure assumptions@>

@d broken_ptr(#)==vlink(#+2)
  {an insertion for this class will break here if anywhere}
@d broken_ins(#)==vinfo(#+2) {this insertion might break at |broken_ptr|}
@d last_ins_ptr(#)==vlink(#+3) {the most recent insertion for this |subtype|}
@d best_ins_ptr(#)==vinfo(#+3) {the optimum most recent insertion}

@<Initialize the special list heads...@>=
subtype(page_ins_head):=65535;
type(page_ins_head):=split_up_node; vlink(page_ins_head):=page_ins_head;

@ An array |page_so_far| records the heights and depths of everything
on the current page. This array contains six |scaled| numbers, like the
similar arrays already considered in |line_break| and |vert_break|; and it
also contains |page_goal| and |page_depth|, since these values are
all accessible to the user via |set_page_dimen| commands. The
value of |page_so_far[1]| is also called |page_total|.  The stretch
and shrink components of the \.{\\skip} corrections for each insertion are
included in |page_so_far|, but the natural space components of these
corrections are not, since they have been subtracted from |page_goal|.

The variable |page_depth| records the depth of the current page; it has been
adjusted so that it is at most |page_max_depth|. The variable
|last_glue| points to the glue specification of the most recent node
contributed from the contribution list, if this was a glue node; otherwise
|last_glue=max_halfword|. (If the contribution list is nonempty,
however, the value of |last_glue| is not necessarily accurate.)
The variables |last_penalty|, |last_kern|, and |last_node_type|
are similar.  And
finally, |insert_penalties| holds the sum of the penalties associated with
all split and floating insertions.

@d page_goal==page_so_far[0] {desired height of information on page being built}
@d page_total==page_so_far[1] {height of the current page}
@d page_shrink==page_so_far[6] {shrinkability of the current page}
@d page_depth==page_so_far[7] {depth of the current page}

@<Glob...@>=
@!page_so_far:array [0..7] of scaled; {height and glue of the current page}
@!last_glue:pointer; {used to implement \.{\\lastskip}}
@!last_penalty:integer; {used to implement \.{\\lastpenalty}}
@!last_kern:scaled; {used to implement \.{\\lastkern}}
@!last_node_type:integer; {used to implement \.{\\lastnodetype}}
@!insert_penalties:integer; {sum of the penalties for held-over insertions}

@ @<Put each...@>=
primitive_tex("pagegoal",set_page_dimen,0,0);
@!@:page_goal_}{\.{\\pagegoal} primitive@>
primitive_tex("pagetotal",set_page_dimen,1,0);
@!@:page_total_}{\.{\\pagetotal} primitive@>
primitive_tex("pagestretch",set_page_dimen,2,0);
@!@:page_stretch_}{\.{\\pagestretch} primitive@>
primitive_tex("pagefilstretch",set_page_dimen,3,0);
@!@:page_fil_stretch_}{\.{\\pagefilstretch} primitive@>
primitive_tex("pagefillstretch",set_page_dimen,4,0);
@!@:page_fill_stretch_}{\.{\\pagefillstretch} primitive@>
primitive_tex("pagefilllstretch",set_page_dimen,5,0);
@!@:page_filll_stretch_}{\.{\\pagefilllstretch} primitive@>
primitive_tex("pageshrink",set_page_dimen,6,0);
@!@:page_shrink_}{\.{\\pageshrink} primitive@>
primitive_tex("pagedepth",set_page_dimen,7,0);
@!@:page_depth_}{\.{\\pagedepth} primitive@>

@ @d print_plus_end(#)==print(#);@+end
@d print_plus(#)==if page_so_far[#]<>0 then
  begin print(" plus "); print_scaled(page_so_far[#]); print_plus_end

@p procedure print_totals;
begin print_scaled(page_total);
print_plus(2)("");
print_plus(3)("fil");
print_plus(4)("fill");
print_plus(5)("filll");
if page_shrink<>0 then
  begin print(" minus "); print_scaled(page_shrink);
  end;
end;

@ @<Show the status of the current page@>=
if page_head<>page_tail then
  begin print_nl("### current page:");
  if output_active then print(" (held over for next output)");
@.held over for next output@>
  show_box(vlink(page_head));
  if page_contents>empty then
    begin print_nl("total height "); print_totals;
@:total_height}{\.{total height}@>
    print_nl(" goal height "); print_scaled(page_goal);
@.goal height@>
    r:=vlink(page_ins_head);
    while r<>page_ins_head do
      begin print_ln; print_esc("insert"); t:=qo(subtype(r));
      print_int(t); print(" adds ");
      if count(t)=1000 then t:=height(r)
      else t:=x_over_n(height(r),1000)*count(t);
      print_scaled(t);
      if type(r)=split_up_node then
        begin q:=page_head; t:=0;
        repeat q:=vlink(q);
        if (type(q)=ins_node)and(subtype(q)=subtype(r)) then incr(t);
        until q=broken_ins(r);
        print(", #"); print_int(t); print(" might split");
        end;
      r:=vlink(r);
      end;
    end;
  end

@ Here is a procedure that is called when the |page_contents| is changing
from |empty| to |inserts_only| or |box_there|.

@d set_page_so_far_zero(#)==page_so_far[#]:=0

@p procedure freeze_page_specs(@!s:small_number);
begin page_contents:=s;
page_goal:=vsize; page_max_depth:=max_depth;
page_depth:=0; do_all_six(set_page_so_far_zero);
least_page_cost:=awful_bad;
@!stat if tracing_pages>0 then
  begin begin_diagnostic;
  print_nl("%% goal height="); print_scaled(page_goal);
@.goal height@>
  print(", max depth="); print_scaled(page_max_depth);
  end_diagnostic(false);
  end;@;@+tats@;@/
end;

@ Pages are built by appending nodes to the current list in \TeX's
vertical mode, which is at the outermost level of the semantic nest. This
vlist is split into two parts; the ``current page'' that we have been
talking so much about already, and the ``contribution list'' that receives
new nodes as they are created.  The current page contains everything that
the page builder has accounted for in its data structures, as described
above, while the contribution list contains other things that have been
generated by other parts of \TeX\ but have not yet been
seen by the page builder.
The contribution list starts at |vlink(contrib_head)|, and it ends at the
current node in \TeX's vertical mode.

When \TeX\ has appended new material in vertical mode, it calls the procedure
|build_page|, which tries to catch up by moving nodes from the contribution
list to the current page. This procedure will succeed in its goal of
emptying the contribution list, unless a page break is discovered, i.e.,
unless the current page has grown to the point where the optimum next
page break has been determined. In the latter case, the nodes after the
optimum break will go back onto the contribution list, and control will
effectively pass to the user's output routine.

We make |type(page_head)=glue_node|, so that an initial glue node on
the current page will not be considered a valid breakpoint.

@<Initialize the special list...@>=
type(page_head):=glue_node; subtype(page_head):=normal;

@ The global variable |output_active| is true during the time the
user's output routine is driving \TeX.

@<Glob...@>=
@!output_active:boolean; {are we in the midst of an output routine?}

@ @<Set init...@>=
output_active:=false; insert_penalties:=0;

@ The page builder is ready to start a fresh page if we initialize
the following state variables. (However, the page insertion list is initialized
elsewhere.)

@<Start a new current page@>=
page_contents:=empty; page_tail:=page_head; vlink(page_head):=null;@/
last_glue:=max_halfword; last_penalty:=0; last_kern:=0;
last_node_type:=-1;
page_depth:=0; page_max_depth:=0

@ At certain times box \outputbox is supposed to be void (i.e., |null|),
or an insertion box is supposed to be ready to accept a vertical list.
If not, an error message is printed, and the following subroutine
flushes the unwanted contents, reporting them to the user.

@p procedure box_error(@!n:eight_bits);
begin error; begin_diagnostic;
print_nl("The following box has been deleted:");
@.The following...deleted@>
show_box(box(n)); end_diagnostic(true);
flush_node_list(box(n)); box(n):=null;
end;

@ The following procedure guarantees that a given box register
does not contain an \.{\\hbox}.

@p procedure ensure_vbox(@!n:eight_bits);
var p:pointer; {the box register contents}
begin p:=box(n);
if p<>null then if type(p)=hlist_node then
  begin print_err("Insertions can only be added to a vbox");
@.Insertions can only...@>
  help3("Tut tut: You're trying to \insert into a")@/
    ("\box register that now contains an \hbox.")@/
    ("Proceed, and I'll discard its present contents.");
  box_error(n);
  end;
end;

@ \TeX\ is not always in vertical mode at the time |build_page|
is called; the current mode reflects what \TeX\ should return to, after
the contribution list has been emptied. A call on |build_page| should
be immediately followed by `|goto big_switch|', which is \TeX's central
control point.

@d contribute=80 {go here to link a node into the current page}

@p @t\4@>@<Declare the procedure called |fire_up|@>@;@/
procedure build_page; {append contributions to the current page}
label exit,done,done1,continue,contribute,update_heights;
var p:pointer; {the node being appended}
@!q,@!r:pointer; {nodes being examined}
@!b,@!c:integer; {badness and cost of current page}
@!pi:integer; {penalty to be added to the badness}
@!n:min_quarterword..255; {insertion box number}
@!delta,@!h,@!w:scaled; {sizes used for insertion calculations}
begin pi:=0;
if (vlink(contrib_head)=null)or output_active then return;
repeat continue: p:=vlink(contrib_head);@/
@<Update the values of |last_glue|, |last_penalty|, and |last_kern|@>;
@<Move node |p| to the current page; if it is time for a page break,
  put the nodes following the break back onto the contribution list,
  and |return| to the user's output routine if there is one@>;
until vlink(contrib_head)=null;
@<Make the contribution list empty by setting its tail to |contrib_head|@>;
exit:end;

@ @d contrib_tail==nest[0].tail_field {tail of the contribution list}

@<Make the contribution list empty...@>=
if nest_ptr=0 then tail:=contrib_head {vertical mode}
else contrib_tail:=contrib_head {other modes}

@ @<Update the values of |last_glue|...@>=
if last_glue<>max_halfword then delete_glue_ref(last_glue);
last_penalty:=0; last_kern:=0;
last_node_type:=type(p)+1;
if type(p)=glue_node then
  begin last_glue:=glue_ptr(p); add_glue_ref(last_glue);
  end
else  begin last_glue:=max_halfword;
  if type(p)=penalty_node then last_penalty:=penalty(p)
  else if type(p)=kern_node then last_kern:=width(p);
  end

@ The code here is an example of a many-way switch into routines that
merge together in different places. Some people call this unstructured
programming, but the author doesn't see much wrong with it, as long as
@^Knuth, Donald Ervin@>
the various labels have a well-understood meaning.

@<Move node |p| to the current page; ...@>=
@<If the current page is empty and node |p| is to be deleted, |goto done1|;
  otherwise use node |p| to update the state of the current page;
  if this node is an insertion, |goto contribute|; otherwise if this node
  is not a legal breakpoint, |goto contribute| or |update_heights|;
  otherwise set |pi| to the penalty associated with this breakpoint@>;
@<Check if node |p| is a new champion breakpoint; then \(if)if it is time for
  a page break, prepare for output, and either fire up the user's
  output routine and |return| or ship out the page and |goto done|@>;
if (type(p)<glue_node)or(type(p)>kern_node) then goto contribute;
update_heights:@<Update the current page measurements with respect to the
  glue or kern specified by node~|p|@>;
contribute: @<Make sure that |page_max_depth| is not exceeded@>;
@<Link node |p| into the current page and |goto done|@>;
done1:@<Recycle node |p|@>;
done:

@ @<Link node |p| into the current page and |goto done|@>=
vlink(page_tail):=p; page_tail:=p;
vlink(contrib_head):=vlink(p); vlink(p):=null; goto done

@ @<Recycle node |p|@>=
vlink(contrib_head):=vlink(p); vlink(p):=null;
if saving_vdiscards>0 then
  begin if page_disc=null then page_disc:=p@+else vlink(tail_page_disc):=p;
  tail_page_disc:=p;
  end
else flush_node_list(p)

@ The title of this section is already so long, it seems best to avoid
making it more accurate but still longer, by mentioning the fact that a
kern node at the end of the contribution list will not be contributed until
we know its successor.

@<If the current page is empty...@>=
case type(p) of
hlist_node_case,vlist_node_case,rule_node_case: if page_contents<box_there then
    @<Initialize the current page, insert the \.{\\topskip} glue
      ahead of |p|, and |goto continue|@>
  else @<Prepare to move a box or rule node to the current page,
    then |goto contribute|@>;
whatsit_node_case: @<Prepare to move whatsit |p| to the current page,
                     then |goto contribute|@>;
glue_node_case: if page_contents<box_there then goto done1
  else if precedes_break(page_tail) then pi:=0
  else goto update_heights;
kern_node_case: if page_contents<box_there then goto done1
  else if vlink(p)=null then return
  else if type(vlink(p))=glue_node then pi:=0
  else goto update_heights;
penalty_node_case: if page_contents<box_there then goto done1@+else pi:=penalty(p);
mark_node_case: goto contribute;
ins_node_case: @<Append an insertion to the current page and |goto contribute|@>;
othercases confusion("page")
@:this can't happen page}{\quad page@>
endcases

@ @<Initialize the current page, insert the \.{\\topskip} glue...@>=
begin if page_contents=empty then freeze_page_specs(box_there)
else page_contents:=box_there;
q:=new_skip_param(top_skip_code); {now |temp_ptr=glue_ptr(q)|}
if (type(p)=hlist_node) and is_mirrored(body_direction) then begin
  if width(temp_ptr)>depth(p) then width(temp_ptr):=width(temp_ptr)-depth(p)
  else width(temp_ptr):=0;
  end
else begin
  if width(temp_ptr)>height(p) then width(temp_ptr):=width(temp_ptr)-height(p)
  else width(temp_ptr):=0;
  end;
vlink(q):=p; vlink(contrib_head):=q; goto continue;
end

@ @<Prepare to move a box or rule node to the current page...@>=
begin
if (type(p)=hlist_node) and is_mirrored(body_direction) then begin
  page_total:=page_total+page_depth+depth(p);
  page_depth:=height(p);
  end
else begin
  page_total:=page_total+page_depth+height(p);
  page_depth:=depth(p);
  end;
goto contribute;
end

@ @<Make sure that |page_max_depth| is not exceeded@>=
if page_depth>page_max_depth then
  begin page_total:=@|
    page_total+page_depth-page_max_depth;@/
  page_depth:=page_max_depth;
  end;

@ @<Update the current page measurements with respect to the glue...@>=
if type(p)=kern_node then q:=p
else begin q:=glue_ptr(p);
if stretch_order(q)>1 then
  page_so_far[1+stretch_order(q)]:=@|
    page_so_far[1+stretch_order(q)]+stretch(q)@/
else
  page_so_far[2+stretch_order(q)]:=@|
    page_so_far[2+stretch_order(q)]+stretch(q);@/
  page_shrink:=page_shrink+shrink(q);
  if (shrink_order(q)<>normal)and(shrink(q)<>0) then
    begin@t@>@;@/
    print_err("Infinite glue shrinkage found on current page");@/
@.Infinite glue shrinkage...@>
    help4("The page about to be output contains some infinitely")@/
      ("shrinkable glue, e.g., `\vss' or `\vskip 0pt minus 1fil'.")@/
      ("Such glue doesn't belong there; but you can safely proceed,")@/
      ("since the offensive shrinkability has been made finite.");
    error;
    r:=new_spec(q); shrink_order(r):=normal; delete_glue_ref(q);
    glue_ptr(p):=r; q:=r;
    end;
  end;
page_total:=page_total+page_depth+width(q); page_depth:=0

@ @<Check if node |p| is a new champion breakpoint; then \(if)...@>=
if pi<inf_penalty then
  begin @<Compute the badness, |b|, of the current page,
    using |awful_bad| if the box is too full@>;
  if b<awful_bad then
    if pi<=eject_penalty then c:=pi
    else  if b<inf_bad then c:=b+pi+insert_penalties
      else c:=deplorable
  else c:=b;
  if insert_penalties>=10000 then c:=awful_bad;
  @!stat if tracing_pages>0 then @<Display the page break cost@>;@+tats@;@/
  if c<=least_page_cost then
    begin best_page_break:=p; best_size:=page_goal;
    least_page_cost:=c;
    r:=vlink(page_ins_head);
    while r<>page_ins_head do
      begin best_ins_ptr(r):=last_ins_ptr(r);
      r:=vlink(r);
      end;
    end;
  if (c=awful_bad)or(pi<=eject_penalty) then
    begin fire_up(p); {output the current page at the best place}
    if output_active then return; {user's output routine will act}
    goto done; {the page has been shipped out by default output routine}
    end;
  end

@ @<Display the page break cost@>=
begin begin_diagnostic; print_nl("%");
print(" t="); print_totals;@/
print(" g="); print_scaled(page_goal);@/
print(" b=");
if b=awful_bad then print_char("*")@+else print_int(b);
@.*\relax@>
print(" p="); print_int(pi);
print(" c=");
if c=awful_bad then print_char("*")@+else print_int(c);
if c<=least_page_cost then print_char("#");
end_diagnostic(false);
end

@ @<Compute the badness, |b|, of the current page...@>=
if page_total<page_goal then
  if (page_so_far[3]<>0) or (page_so_far[4]<>0) or@|
    (page_so_far[5]<>0) then b:=0
  else b:=badness(page_goal-page_total,page_so_far[2])
else if page_total-page_goal>page_shrink then b:=awful_bad
else b:=badness(page_total-page_goal,page_shrink)

@ @<Append an insertion to the current page and |goto contribute|@>=
begin if page_contents=empty then freeze_page_specs(inserts_only);
n:=subtype(p); r:=page_ins_head;
while n>=subtype(vlink(r)) do r:=vlink(r);
n:=qo(n);
if subtype(r)<>qi(n) then
  @<Create a page insertion node with |subtype(r)=qi(n)|, and
    include the glue correction for box |n| in the
    current page state@>;
if type(r)=split_up_node then insert_penalties:=insert_penalties+float_cost(p)
else  begin last_ins_ptr(r):=p;
  delta:=page_goal-page_total-page_depth+page_shrink;
    {this much room is left if we shrink the maximum}
  if count(n)=1000 then h:=height(p)
  else h:=x_over_n(height(p),1000)*count(n); {this much room is needed}
  if ((h<=0)or(h<=delta))and(height(p)+height(r)<=dimen(n)) then
    begin page_goal:=page_goal-h; height(r):=height(r)+height(p);
    end
  else @<Find the best way to split the insertion, and change
    |type(r)| to |split_up_node|@>;
  end;
goto contribute;
end

@ We take note of the value of \.{\\skip} |n| and the height plus depth
of \.{\\box}~|n| only when the first \.{\\insert}~|n| node is
encountered for a new page. A user who changes the contents of \.{\\box}~|n|
after that first \.{\\insert}~|n| had better be either extremely careful
or extremely lucky, or both.

@<Create a page insertion node...@>=
begin q:=new_node(inserting_node,n); vlink(q):=vlink(r); vlink(r):=q; r:=q;
ensure_vbox(n);
if box(n)=null then height(r):=0
else height(r):=height(box(n))+depth(box(n));
best_ins_ptr(r):=null;@/
q:=skip(n);
if count(n)=1000 then h:=height(r)
else h:=x_over_n(height(r),1000)*count(n);
page_goal:=page_goal-h-width(q);@/
if stretch_order(q)>1 then
  page_so_far[1+stretch_order(q)]:=@|page_so_far[1+stretch_order(q)]+stretch(q)@/
else
  page_so_far[2+stretch_order(q)]:=@|page_so_far[2+stretch_order(q)]+stretch(q);@/
page_shrink:=page_shrink+shrink(q);
if (shrink_order(q)<>normal)and(shrink(q)<>0) then
  begin print_err("Infinite glue shrinkage inserted from "); print_esc("skip");
@.Infinite glue shrinkage...@>
  print_int(n);
  help3("The correction glue for page breaking with insertions")@/
    ("must have finite shrinkability. But you may proceed,")@/
    ("since the offensive shrinkability has been made finite.");
  error;
  end;
end

@ Here is the code that will split a long footnote between pages, in an
emergency. The current situation deserves to be recapitulated: Node |p|
is an insertion into box |n|; the insertion will not fit, in its entirety,
either because it would make the total contents of box |n| greater than
\.{\\dimen} |n|, or because it would make the incremental amount of growth
|h| greater than the available space |delta|, or both. (This amount |h| has
been weighted by the insertion scaling factor, i.e., by \.{\\count} |n|
over 1000.) Now we will choose the best way to break the vlist of the
insertion, using the same criteria as in the \.{\\vsplit} operation.

@<Find the best way to split the insertion...@>=
begin if count(n)<=0 then w:=max_dimen
else  begin w:=page_goal-page_total-page_depth;
  if count(n)<>1000 then w:=x_over_n(w,count(n))*1000;
  end;
if w>dimen(n)-height(r) then w:=dimen(n)-height(r);
q:=vert_break(ins_ptr(p),w,depth(p));
height(r):=height(r)+best_height_plus_depth;
@!stat if tracing_pages>0 then @<Display the insertion split cost@>;@+tats@;@/
if count(n)<>1000 then
  best_height_plus_depth:=x_over_n(best_height_plus_depth,1000)*count(n);
page_goal:=page_goal-best_height_plus_depth;
type(r):=split_up_node; broken_ptr(r):=q; broken_ins(r):=p;
if q=null then insert_penalties:=insert_penalties+eject_penalty
else if type(q)=penalty_node then insert_penalties:=insert_penalties+penalty(q);
end

@ @<Display the insertion split cost@>=
begin begin_diagnostic; print_nl("% split"); print_int(n);
@.split@>
print(" to "); print_scaled(w);
print_char(","); print_scaled(best_height_plus_depth);@/
print(" p=");
if q=null then print_int(eject_penalty)
else if type(q)=penalty_node then print_int(penalty(q))
else print_char("0");
end_diagnostic(false);
end

@ When the page builder has looked at as much material as could appear before
the next page break, it makes its decision. The break that gave minimum
badness will be used to put a completed ``page'' into box \.{\\outputbox}, with insertions
appended to their other boxes.

We also set the values of |top_mark|, |first_mark|, and |bot_mark|. The
program uses the fact that |bot_mark(x)<>null| implies |first_mark(x)<>null|;
it also knows that |bot_mark(x)=null| implies |top_mark(x)=first_mark(x)=null|.

The |fire_up| subroutine prepares to output the current page at the best
place; then it fires up the user's output routine, if there is one,
or it simply ships out the page. There is one parameter, |c|, which represents
the node that was being contributed to the page when the decision to
force an output was made.

@<Declare the procedure called |fire_up|@>=
procedure fire_up(@!c:pointer);
label exit;
var p,@!q,@!r,@!s:pointer; {nodes being examined and/or changed}
@!prev_p:pointer; {predecessor of |p|}
@!n:min_quarterword..255; {insertion box number}
@!wait:boolean; {should the present insertion be held over?}
@!save_vbadness:integer; {saved value of |vbadness|}
@!save_vfuzz: scaled; {saved value of |vfuzz|}
@!save_split_top_skip: pointer; {saved value of |split_top_skip|}
@!i: halfword; { for looping through the marks}
begin @<Set the value of |output_penalty|@>;
for i:=0 to biggest_used_mark do begin
  if bot_mark(i)<>null then
    begin if top_mark(i)<>null then delete_token_ref(top_mark(i));
    top_mark(i):=bot_mark(i); add_token_ref(top_mark(i));
    delete_first_mark(i);
    end;
  end;
@<Put the \(o)optimal current page into box |output_box|, update |first_mark| and
  |bot_mark|, append insertions to their boxes, and put the
  remaining nodes back on the contribution list@>;
for i:=0 to biggest_used_mark do begin
  if (top_mark(i)<>null)and(first_mark(i)=null) then
    begin first_mark(i):=top_mark(i); add_token_ref(top_mark(i));
    end;
  end;
if output_routine<>null then begin
  if dead_cycles>=max_dead_cycles then
    @<Explain that too many dead cycles have occurred in a row@>
  else @<Fire up the user's output routine and |return|@>;
  end;
@<Perform the default output routine@>;
exit:end;

@ @<Set the value of |output_penalty|@>=
if type(best_page_break)=penalty_node then
  begin geq_word_define(int_base+output_penalty_code,penalty(best_page_break));
  penalty(best_page_break):=inf_penalty;
  end
else geq_word_define(int_base+output_penalty_code,inf_penalty)

@ As the page is finally being prepared for output,
pointer |p| runs through the vlist, with |prev_p| trailing behind;
pointer |q| is the tail of a list of insertions that
are being held over for a subsequent page.

@<Put the \(o)optimal current page into box ...@>=
if c=best_page_break then best_page_break:=null; {|c| not yet linked in}
@<Ensure that box |output_box| is empty before output@>;
insert_penalties:=0; {this will count the number of insertions held over}
save_split_top_skip:=split_top_skip;
if holding_inserts<=0 then
  @<Prepare all the boxes involved in insertions to act as queues@>;
q:=hold_head; vlink(q):=null; prev_p:=page_head; p:=vlink(prev_p);
while p<>best_page_break do
  begin if type(p)=ins_node then
    begin if holding_inserts<=0 then
       @<Either insert the material specified by node |p| into the
         appropriate box, or hold it for the next page;
         also delete node |p| from the current page@>;
    end
  else if type(p)=mark_node then @<Update the values of
    |first_mark| and |bot_mark|@>;
  prev_p:=p; p:=vlink(prev_p);
  end;
split_top_skip:=save_split_top_skip;
@<Break the current page at node |p|, put it in box~|output_box|,
  and put the remaining nodes on the contribution list@>;
@<Delete \(t)the page-insertion nodes@>

@ @<Ensure that box |output_box| is empty before output@>=
if box(output_box)<>null then
  begin print_err(""); print_esc("box"); print_int(output_box); print(" is not void");
@:box\\outputbox}{\.{\\box\\outputbox is not void}@>
  help2("You shouldn't use \box\outputbox except in \output routines.")@/
    ("Proceed, and I'll discard its present contents.");
  box_error(output_box);
  end

@ @<Update the values of |first_mark| and |bot_mark|@>=
begin if first_mark(mark_class(p))=null then
  begin first_mark(mark_class(p)):=mark_ptr(p);
  add_token_ref(first_mark(mark_class(p)));
  end;
if bot_mark(mark_class(p))<>null then delete_token_ref(bot_mark(mark_class(p)));
bot_mark(mark_class(p)):=mark_ptr(p); add_token_ref(bot_mark(mark_class(p)));
end;

@ When the following code is executed, the current page runs from node
|vlink(page_head)| to node |prev_p|, and the nodes from |p| to |page_tail|
are to be placed back at the front of the contribution list. Furthermore
the heldover insertions appear in a list from |vlink(hold_head)| to |q|; we
will put them into the current page list for safekeeping while the user's
output routine is active.  We might have |q=hold_head|; and |p=null| if
and only if |prev_p=page_tail|. Error messages are suppressed within
|vpackage|, since the box might appear to be overfull or underfull simply
because the stretch and shrink from the \.{\\skip} registers for inserts
are not actually present in the box.

@<Break the current page at node |p|, put it...@>=
if p<>null then
  begin if vlink(contrib_head)=null then begin
    if nest_ptr=0 then tail:=page_tail
    else contrib_tail:=page_tail;
    end;
  vlink(page_tail):=vlink(contrib_head);
  vlink(contrib_head):=p;
  vlink(prev_p):=null;
  end;
save_vbadness:=vbadness; vbadness:=inf_bad;
save_vfuzz:=vfuzz; vfuzz:=max_dimen; {inhibit error messages}
pack_direction:=body_direction;
box(output_box):=filtered_vpackage(vlink(page_head),best_size,exactly,page_max_depth,output_group);
vbadness:=save_vbadness; vfuzz:=save_vfuzz;
if last_glue<>max_halfword then delete_glue_ref(last_glue);
@<Start a new current page@>; {this sets |last_glue:=max_halfword|}
if q<>hold_head then
  begin vlink(page_head):=vlink(hold_head); page_tail:=q;
  end

@ If many insertions are supposed to go into the same box, we want to know
the position of the last node in that box, so that we don't need to waste time
when linking further information into it. The |last_ins_ptr| fields of the
page insertion nodes are therefore used for this purpose during the
packaging phase.

@<Prepare all the boxes involved in insertions to act as queues@>=
begin r:=vlink(page_ins_head);
while r<>page_ins_head do
  begin if best_ins_ptr(r)<>null then
    begin n:=qo(subtype(r)); ensure_vbox(n);
    if box(n)=null then box(n):=new_null_box;
    p:=box(n)+list_offset;
    while vlink(p)<>null do p:=vlink(p);
    last_ins_ptr(r):=p;
    end;
  r:=vlink(r);
  end;
end

@ @<Delete \(t)the page-insertion nodes@>=
r:=vlink(page_ins_head);
while r<>page_ins_head do
  begin q:=vlink(r); flush_node(r); r:=q;
  end;
vlink(page_ins_head):=page_ins_head

@ We will set |best_ins_ptr:=null| and package the box corresponding to
insertion node~|r|, just after making the final insertion into that box.
If this final insertion is `|split_up_node|', the remainder after splitting
and pruning (if any) will be carried over to the next page.

@<Either insert the material specified by node |p| into...@>=
begin r:=vlink(page_ins_head);
while subtype(r)<>subtype(p) do r:=vlink(r);
if best_ins_ptr(r)=null then wait:=true
else  begin wait:=false; s:=last_ins_ptr(r); vlink(s):=ins_ptr(p);
  if best_ins_ptr(r)=p then
    @<Wrap up the box specified by node |r|, splitting node |p| if
    called for; set |wait:=true| if node |p| holds a remainder after
    splitting@>
  else  begin while vlink(s)<>null do s:=vlink(s);
    last_ins_ptr(r):=s;
    end;
  end;
@<Either append the insertion node |p| after node |q|, and remove it
  from the current page, or delete |node(p)|@>;
end

@ @<Wrap up the box specified by node |r|, splitting node |p| if...@>=
begin if type(r)=split_up_node then
  if (broken_ins(r)=p)and(broken_ptr(r)<>null) then
    begin while vlink(s)<>broken_ptr(r) do s:=vlink(s);
    vlink(s):=null;
    split_top_skip:=split_top_ptr(p);
    ins_ptr(p):=prune_page_top(broken_ptr(r),false);
    if ins_ptr(p)<>null then
      begin temp_ptr:=vpack(ins_ptr(p),natural);
      height(p):=height(temp_ptr)+depth(temp_ptr);
      list_ptr(temp_ptr):=null; flush_node(temp_ptr); wait:=true;
      end;
    end;
best_ins_ptr(r):=null;
n:=qo(subtype(r));
temp_ptr:=list_ptr(box(n));
list_ptr(box(n)):=null; flush_node(box(n));
pack_direction:=body_direction;
box(n):=vpack(temp_ptr,natural);
end

@ @<Either append the insertion node |p|...@>=
vlink(prev_p):=vlink(p); vlink(p):=null;
if wait then
  begin vlink(q):=p; q:=p; incr(insert_penalties);
  end
else  begin ins_ptr(p):=null; flush_node(p);
  end;
p:=prev_p

@ The list of heldover insertions, running from |vlink(page_head)| to
|page_tail|, must be moved to the contribution list when the user has
specified no output routine.

@<Perform the default output routine@>=
begin if vlink(page_head)<>null then
  begin if vlink(contrib_head)=null then
    if nest_ptr=0 then tail:=page_tail@+else contrib_tail:=page_tail
  else vlink(page_tail):=vlink(contrib_head);
  vlink(contrib_head):=vlink(page_head);
  vlink(page_head):=null; page_tail:=page_head;
  end;
flush_node_list(page_disc); page_disc:=null;
ship_out(box(output_box)); box(output_box):=null;
end

@ @<Explain that too many dead cycles have occurred in a row@>=
begin print_err("Output loop---"); print_int(dead_cycles);
@.Output loop...@>
print(" consecutive dead cycles");
help3("I've concluded that your \output is awry; it never does a")@/
("\shipout, so I'm shipping \box\outputbox out myself. Next time")@/
("increase \maxdeadcycles if you want me to be more patient!"); error;
end

@ @<Fire up the user's output routine and |return|@>=
begin output_active:=true;
incr(dead_cycles);
push_nest; mode:=-vmode; prev_depth:=pdf_ignored_dimen; mode_line:=-line;
begin_token_list(output_routine,output_text);
new_save_level(output_group); normal_paragraph;
scan_left_brace;
return;
end

@ When the user's output routine finishes, it has constructed a vlist
in internal vertical mode, and \TeX\ will do the following:

@<Resume the page builder after an output routine has come to an end@>=
begin if (loc<>null) or
 ((token_type<>output_text)and(token_type<>backed_up)) then
  @<Recover from an unbalanced output routine@>;
end_token_list; {conserve stack space in case more outputs are triggered}
end_graf; unsave; output_active:=false; insert_penalties:=0;@/
@<Ensure that box |output_box| is empty after output@>;
if tail<>head then {current list goes after heldover insertions}
  begin vlink(page_tail):=vlink(head);
  page_tail:=tail;
  end;
if vlink(page_head)<>null then {and both go before heldover contributions}
  begin if vlink(contrib_head)=null then contrib_tail:=page_tail;
  vlink(page_tail):=vlink(contrib_head);
  vlink(contrib_head):=vlink(page_head);
  vlink(page_head):=null; page_tail:=page_head;
  end;
flush_node_list(page_disc); page_disc:=null;
pop_nest; check_filter('after_output'); build_page;
end

@ @<Recover from an unbalanced output routine@>=
begin print_err("Unbalanced output routine");
@.Unbalanced output routine@>
help2("Your sneaky output routine has problematic {'s and/or }'s.")@/
("I can't handle that very well; good luck."); error;
repeat get_token;
until loc=null;
end {loops forever if reading from a file, since |null=min_halfword<=0|}

@ @<Ensure that box |output_box| is empty after output@>=
if box(output_box)<>null then
  begin print_err("Output routine didn't use all of ");
  print_esc("box"); print_int(output_box);
@.Output routine didn't use...@>
  help3("Your \output commands should empty \box\outputbox,")@/
    ("e.g., by saying `\shipout\box\outputbox'.")@/
    ("Proceed; I'll discard its present contents.");
  box_error(output_box);
  end

@* \[46] The chief executive.
We come now to the |main_control| routine, which contains the master
switch that causes all the various pieces of \TeX\ to do their things,
in the right order.

In a sense, this is the grand climax of the program: It applies all the
tools that we have worked so hard to construct. In another sense, this is
the messiest part of the program: It necessarily refers to other pieces
of code all over the place, so that a person can't fully understand what is
going on without paging back and forth to be reminded of conventions that
are defined elsewhere. We are now at the hub of the web, the central nervous
system that touches most of the other parts and ties them together.
@^brain@>

The structure of |main_control| itself is quite simple. There's a label
called |big_switch|, at which point the next token of input is fetched
using |get_x_token|. Then the program branches at high speed into one of
about 100 possible directions, based on the value of the current
mode and the newly fetched command code; the sum |abs(mode)+cur_cmd|
indicates what to do next. For example, the case `|vmode+letter|' arises
when a letter occurs in vertical mode (or internal vertical mode); this
case leads to instructions that initialize a new paragraph and enter
horizontal mode.

The big |case| statement that contains this multiway switch has been labeled
|reswitch|, so that the program can |goto reswitch| when the next token
has already been fetched. Most of the cases are quite short; they call
an ``action procedure'' that does the work for that case, and then they
either |goto reswitch| or they ``fall through'' to the end of the |case|
statement, which returns control back to |big_switch|. Thus, |main_control|
is not an extremely large procedure, in spite of the multiplicity of things
it must do; it is small enough to be handled by \PASCAL\ compilers that put
severe restrictions on procedure size.
@!@^action procedure@>

One case is singled out for special treatment, because it accounts for most
of \TeX's activities in typical applications. The process of reading simple
text and converting it into |char_node| records, while looking for ligatures
and kerns, is part of \TeX's ``inner loop''; the whole program runs
efficiently when its inner loop is fast, so this part has been written
with particular care.

@ We shall concentrate first on the inner loop of |main_control|, deferring
consideration of the other cases until later.
@^inner loop@>

@d big_switch=60 {go here to branch on the next token of input}

@p @t\4@>@<Declare action procedures for use by |main_control|@>@;
@t\4@>@<Declare the procedure called |handle_right_brace|@>@;
procedure main_control; {governs \TeX's activities}
label big_switch,reswitch,continue,exit;
var@!t,k:integer; {general-purpose temporary variables}
p:pointer; {for whatsit nodes and testing whether an auto kern should be inserted}
chr_stack:integer; { to temporarily save an |cur_chr| to be appended }
mval:mathcodeval; { to build up an argument to |set_math_char| }
begin t:=0; {for -Wall}
chr_stack:=-1;
if every_job<>null then begin_token_list(every_job,every_job_text);
big_switch: get_x_token;@/
reswitch: @<Give diagnostic information, if requested@>;
case abs(mode)+cur_cmd of
hmode+letter,hmode+other_char,hmode+char_given,hmode+char_num: begin
  if abs(mode)+cur_cmd=hmode+char_num then begin
    scan_char_num; cur_chr:=cur_val;
    end;
  if is_last_ocp(current_ocp_lstack,current_ocp_no) then begin
    @<Append character |cur_chr| and the following characters (if~any)
      to the current hlist in the current font; |goto reswitch| when
      a non-character has been fetched@>;
    end
  else begin
    @<Create a buffer with character |cur_chr| and the following
      characters (if~any) and then apply the current active OCP filter
      to this buffer@>;
    end;
  end;
hmode+no_boundary: begin @<Append a |cancel_boundary_node| @>;
  end;
hmode+char_ghost: begin t:=cur_chr; get_x_token;
  if (cur_cmd=letter)or(cur_cmd=other_char)or(cur_cmd=char_given)or
   (cur_cmd=char_num) then begin
        p:=new_glyph(cur_font,cur_chr);
    if t=0 then begin set_is_leftghost(p); end
    else begin set_is_rightghost(p); end;
    tail_append(p);
    end;
  end;
hmode+spacer,hmode+ex_space,mmode+ex_space:
if (abs(mode)+cur_cmd=hmode+spacer) and
   (not (space_factor = 1000)) then
  app_space
else begin
  @<Append a normal inter-word space to the current list@>;
  end;
@t\4@>@<Cases of |main_control| that are not part of the inner loop@>@;
end; {of the big |case| statement}
goto big_switch;
exit:end;

@ When a new token has just been fetched at |big_switch|, we have an
ideal place to monitor \TeX's activity.
@^debugging@>

@<Give diagnostic information, if requested@>=
if interrupt<>0 then if OK_to_interrupt then
  begin back_input; check_interrupt; goto big_switch;
  end;
if tracing_commands>0 then show_cur_cmd_chr

@ The following part of the program was first written in a structured
manner, according to the philosophy that ``premature optimization is
the root of all evil.'' Then it was rearranged into pieces of
spaghetti so that the most common actions could proceed with little or
no redundancy. And finally, it is replaced by a completely standalone
loop over the node list: luatex does not have a |main+loop| at all.
@^inner loop@>

@<Glob...@>=
@!main_p:pointer; {temporary register for list manipulation}
@!main_s:integer; {space factor value}

@ We leave the |space_factor| unchanged if |sf_code(cur_chr)=0|; otherwise we
set it equal to |sf_code(cur_chr)|, except that it should never change
from a value less than 1000 to a value exceeding 1000. The most common
case is |sf_code(cur_chr)=1000|, so we want that case to be fast.

@d adjust_space_factor==@t@>@;@/
  main_s:=get_sf_code(cur_chr);
  if main_s=1000 then space_factor:=1000
  else if main_s<1000 then
    begin if main_s>0 then space_factor:=main_s;
    end
  else if space_factor<1000 then space_factor:=1000
  else space_factor:=main_s

@<Append character |cur_chr|...@>=
continue: adjust_space_factor;@/
chr_stack:=cur_chr;
tail_append(new_char(cur_font,chr_stack));
get_x_token;
if (cur_cmd=letter)or(cur_cmd=other_char)or
   (cur_cmd=char_given)or(cur_cmd=char_num) then begin
  if cur_cmd=char_num then begin
    scan_char_num; cur_chr:=cur_val;
    end;
  if (chr_stack=ex_hyphen_char)and(cur_chr<>ex_hyphen_char)and(mode>0) then begin
    tail:=compound_word_break(tail,cur_lang);
    subtype(tail):=automatic_disc;
    end;
  goto continue;
  end
else begin
  if (chr_stack=ex_hyphen_char) and (mode>0) then begin
    tail:=compound_word_break(tail,cur_lang);
    subtype(tail):=automatic_disc;
    end;
  chr_stack:=-1;
  goto reswitch;
  end

@ The occurrence of blank spaces is almost part of \TeX's inner loop,
@^inner loop@>
since we usually encounter about one space for every five non-blank characters.
Therefore |main_control| gives second-highest priority to ordinary spaces.

When a glue parameter like \.{\\spaceskip} is set to `\.{0pt}', we will
see to it later that the corresponding glue specification is precisely
|zero_glue|, not merely a pointer to some specification that happens
to be full of zeroes. Therefore it is simple to test whether a glue parameter
is zero or~not.

@<Append a normal inter-word space...@>=
if space_skip=zero_glue then
  begin @<Find the glue specification, |main_p|, for
    text spaces in the current font@>;
  temp_ptr:=new_glue(main_p);
  end
else temp_ptr:=new_param_glue(space_skip_code);
vlink(tail):=temp_ptr; tail:=temp_ptr


@ From Knuth: ``Having |font_glue| allocated for each text font saves
both time and memory.''  That may be true, but it also punches through
the API wall for fonts, so I removed that -- Taco. But a bit of caching
is very welcome, which is why I need to have the next two globals:

@<Glob...@>=
space_spec_font:internal_font_number;
space_spec_cache:halfword;

@ @<Set init...@>=
space_spec_font:=0;
space_spec_cache:=zero_glue;

@ @<Find the glue specification...@>=
begin
if cur_font<>space_spec_font then begin
  if space_spec_cache<>zero_glue then
     delete_glue_ref(space_spec_cache);
  space_spec_cache:=new_spec(zero_glue);
  width(space_spec_cache):=space(cur_font);
  stretch(space_spec_cache):=space_stretch(cur_font);
  shrink(space_spec_cache):=space_shrink(cur_font);
  space_spec_font:=cur_font;
  end;
main_p:=space_spec_cache;
end

@ @<Declare act...@>=
procedure app_space; {handle spaces when |space_factor<>1000|}
var@!q:pointer; {glue node}
begin if (space_factor>=2000)and(xspace_skip<>zero_glue) then
  q:=new_param_glue(xspace_skip_code)
else begin if space_skip<>zero_glue then
    main_p:=new_spec(space_skip)
  else begin
    main_p:=new_spec(zero_glue);
    width(main_p):=space(cur_font);
    stretch(main_p):=space_stretch(cur_font);
    shrink(main_p):=space_shrink(cur_font);
  end;
  @<Modify the glue specification in |main_p| according to the space factor@>;
  q:=new_glue(main_p); glue_ref_count(main_p):=null;
  end;
vlink(tail):=q; tail:=q;
end;

@ @<Modify the glue specification in |main_p| according to the space factor@>=
if space_factor>=2000 then width(main_p):=width(main_p)+extra_space(cur_font);
stretch(main_p):=xn_over_d(stretch(main_p),space_factor,1000);
shrink(main_p):=xn_over_d(shrink(main_p),1000,space_factor)

@ Whew---that covers the main loop. We can now proceed at a leisurely
pace through the other combinations of possibilities.

@d any_mode(#)==vmode+#,hmode+#,mmode+# {for mode-independent commands}

@<Cases of |main_control| that are not part of the inner loop@>=
any_mode(relax),vmode+spacer,mmode+spacer,mmode+no_boundary:do_nothing;
any_mode(ignore_spaces): begin
  if cur_chr = 0 then begin
    @<Get the next non-blank non-call...@>;
    goto reswitch;
  end
  else begin
    t:=scanner_status;
    scanner_status:=normal;
    get_filtered_next;
    scanner_status:=t;
    cur_cs  := prim_lookup(text(cur_cs));
    if cur_cs<>undefined_primitive then begin
      cur_cmd := get_prim_eq_type(cur_cs);
      cur_chr := get_prim_equiv(cur_cs);
      cur_tok := (cur_cmd*string_offset)+cur_chr;
      goto reswitch;
      end;
    end;
  end;
vmode+stop: if its_all_over then return; {this is the only way out}
@t\4@>@<Math cases in non-math modes@>;
@t\4@>@<Forbidden cases detected in |main_control|@>@+@,any_mode(mac_param):
  report_illegal_case;
@<Math-only cases in non-math modes, or vice versa@>: insert_dollar_sign;
@t\4@>@<Cases of |main_control| that build boxes and lists@>@;
@t\4@>@<Cases of |main_control| that don't depend on |mode|@>@;
@t\4@>@<Cases of |main_control| that are for extensions to \TeX@>@;

@ Here is a list of cases where the user has probably gotten into or out of math
mode by mistake. \TeX\ will insert a dollar sign and rescan the current token.

@d non_math(#)==vmode+#,hmode+#

@<Math-only cases in non-math modes...@>=
non_math(sup_mark), non_math(sub_mark),
non_math(super_sub_script), non_math(math_comp), non_math(delim_num),
non_math(left_right), non_math(above), non_math(radical),
non_math(math_style), non_math(math_choice), non_math(vcenter),
non_math(non_script), non_math(mkern), non_math(limit_switch),
non_math(mskip), non_math(math_accent),
mmode+endv, mmode+par_end, mmode+stop, mmode+vskip, mmode+un_vbox,
mmode+valign, mmode+hrule

@ @<Math cases in non-math modes@>=
vmode+math_char_num, vmode+math_given, vmode+omath_given, vmode+xmath_given: begin
    back_input; new_graf(true);
    end;
hmode+math_char_num: begin
    if cur_chr=0 then
      mval := scan_mathchar(tex_mathcode)
    else if cur_chr=1 then
      mval := scan_mathchar(aleph_mathcode)
    else if cur_chr=2 then
      mval := scan_mathchar(xetex_mathcode)
    else
      mval := scan_mathchar(xetexnum_mathcode);
    math_char_in_text(mval);
    end;
hmode+math_given: begin
    mval := mathchar_from_integer(cur_chr,tex_mathcode);
    math_char_in_text(mval);
    end;
hmode+omath_given: begin
    mval := mathchar_from_integer(cur_chr,aleph_mathcode);
    math_char_in_text(mval);
    end;
hmode+xmath_given: begin
    mval := mathchar_from_integer(cur_chr,xetex_mathcode);
    math_char_in_text(mval);
    end



@ @<Declare action...@>=
procedure insert_dollar_sign;
begin back_input; cur_tok:=math_shift_token+"$";
print_err("Missing $ inserted");
@.Missing \$ inserted@>
help2("I've inserted a begin-math/end-math symbol since I think")@/
("you left one out. Proceed, with fingers crossed."); ins_error;
end;

@ When erroneous situations arise, \TeX\ usually issues an error message
specific to the particular error. For example, `\.{\\noalign}' should
not appear in any mode, since it is recognized by the |align_peek| routine
in all of its legitimate appearances; a special error message is given
when `\.{\\noalign}' occurs elsewhere. But sometimes the most appropriate
error message is simply that the user is not allowed to do what he or she
has attempted. For example, `\.{\\moveleft}' is allowed only in vertical mode,
and `\.{\\lower}' only in non-vertical modes.  Such cases are enumerated
here and in the other sections referred to under `See also \dots.'

@<Forbidden cases...@>=
vmode+vmove,hmode+hmove,mmode+hmove,any_mode(last_item),

@ The `|you_cant|' procedure prints a line saying that the current command
is illegal in the current mode; it identifies these things symbolically.

@<Declare action...@>=
procedure you_cant;
begin print_err("You can't use `");
@.You can't use x in y mode@>
print_cmd_chr(cur_cmd,cur_chr);
print("' in "); print_mode(mode);
end;

@ @<Declare act...@>=
procedure report_illegal_case;
begin you_cant;
help4("Sorry, but I'm not programmed to handle this case;")@/
("I'll just pretend that you didn't ask for it.")@/
("If you're in the wrong mode, you might be able to")@/
("return to the right one by typing `I}' or `I$' or `I\par'.");@/
error;
end;

@ Some operations are allowed only in privileged modes, i.e., in cases
that |mode>0|. The |privileged| function is used to detect violations
of this rule; it issues an error message and returns |false| if the
current |mode| is negative.

@<Declare act...@>=
function privileged:boolean;
begin if mode>0 then privileged:=true
else  begin report_illegal_case; privileged:=false;
  end;
end;

@ Either \.{\\dump} or \.{\\end} will cause |main_control| to enter the
endgame, since both of them have `|stop|' as their command code.

@<Put each...@>=
primitive_tex("end",stop,0,0);@/
@!@:end_}{\.{\\end} primitive@>
primitive_tex("dump",stop,1,0);@/
@!@:dump_}{\.{\\dump} primitive@>

@ We don't want to leave |main_control| immediately when a |stop| command
is sensed, because it may be necessary to invoke an \.{\\output} routine
several times before things really grind to a halt. (The output routine
might even say `\.{\\gdef\\end\{...\}}', to prolong the life of the job.)
Therefore |its_all_over| is |true| only when the current page
and contribution list are empty, and when the last output was not a
``dead cycle.''

@<Declare act...@>=
function its_all_over:boolean; {do this when \.{\\end} or \.{\\dump} occurs}
label exit;
begin if privileged then
  begin if (page_head=page_tail)and(head=tail)and(dead_cycles=0) then
    begin its_all_over:=true; return;
    end;
  back_input; {we will try to end again after ejecting residual material}
  tail_append(new_null_box);
  width(tail):=hsize;
  tail_append(new_glue(fill_glue));
  tail_append(new_penalty(-@'10000000000));@/
  check_filter('end'); build_page; {append \.{\\hbox to \\hsize\{\}\\vfill\\penalty-'10000000000}}
  end;
its_all_over:=false;
exit:end;

@* \[47] Building boxes and lists.
The most important parts of |main_control| are concerned with \TeX's
chief mission of box-making. We need to control the activities that put
entries on vlists and hlists, as well as the activities that convert
those lists into boxes. All of the necessary machinery has already been
developed; it remains for us to ``push the buttons'' at the right times.

@ As an introduction to these routines, let's consider one of the simplest
cases: What happens when `\.{\\hrule}' occurs in vertical mode, or
`\.{\\vrule}' in horizontal mode or math mode? The code in |main_control|
is short, since the |scan_rule_spec| routine already does most of what is
required; thus, there is no need for a special action procedure.

Note that baselineskip calculations are disabled after a rule in vertical
mode, by setting |prev_depth:=pdf_ignored_dimen|.

@<Cases of |main_control| that build...@>=
vmode+hrule,hmode+vrule,mmode+vrule: begin tail_append(scan_rule_spec);
  if abs(mode)=vmode then prev_depth:=pdf_ignored_dimen
  else if abs(mode)=hmode then space_factor:=1000;
  end;

@ The processing of things like \.{\\hskip} and \.{\\vskip} is slightly
more complicated. But the code in |main_control| is very short, since
it simply calls on the action routine |append_glue|. Similarly, \.{\\kern}
activates |append_kern|.

@<Cases of |main_control| that build...@>=
vmode+vskip,hmode+hskip,mmode+hskip,mmode+mskip: append_glue;
any_mode(kern),mmode+mkern: append_kern;

@ The |hskip| and |vskip| command codes are used for control sequences
like \.{\\hss} and \.{\\vfil} as well as for \.{\\hskip} and \.{\\vskip}.
The difference is in the value of |cur_chr|.

@d fil_code=0 {identifies \.{\\hfil} and \.{\\vfil}}
@d fill_code=1 {identifies \.{\\hfill} and \.{\\vfill}}
@d ss_code=2 {identifies \.{\\hss} and \.{\\vss}}
@d fil_neg_code=3 {identifies \.{\\hfilneg} and \.{\\vfilneg}}
@d skip_code=4 {identifies \.{\\hskip} and \.{\\vskip}}
@d mskip_code=5 {identifies \.{\\mskip}}

@<Put each...@>=
primitive_tex("hskip",hskip,skip_code,0);@/
@!@:hskip_}{\.{\\hskip} primitive@>
primitive_tex("hfil",hskip,fil_code,0);
@!@:hfil_}{\.{\\hfil} primitive@>
primitive_tex("hfill",hskip,fill_code,0);@/
@!@:hfill_}{\.{\\hfill} primitive@>
primitive_tex("hss",hskip,ss_code,0);
@!@:hss_}{\.{\\hss} primitive@>
primitive_tex("hfilneg",hskip,fil_neg_code,0);@/
@!@:hfil_neg_}{\.{\\hfilneg} primitive@>
primitive_tex("vskip",vskip,skip_code,0);@/
@!@:vskip_}{\.{\\vskip} primitive@>
primitive_tex("vfil",vskip,fil_code,0);
@!@:vfil_}{\.{\\vfil} primitive@>
primitive_tex("vfill",vskip,fill_code,0);@/
@!@:vfill_}{\.{\\vfill} primitive@>
primitive_tex("vss",vskip,ss_code,0);
@!@:vss_}{\.{\\vss} primitive@>
primitive_tex("vfilneg",vskip,fil_neg_code,0);@/
@!@:vfil_neg_}{\.{\\vfilneg} primitive@>
primitive_tex("mskip",mskip,mskip_code,0);@/
@!@:mskip_}{\.{\\mskip} primitive@>
primitive_tex("kern",kern,explicit,0);
@!@:kern_}{\.{\\kern} primitive@>
primitive_tex("mkern",mkern,mu_glue,0);@/
@!@:mkern_}{\.{\\mkern} primitive@>

@ All the work relating to glue creation has been relegated to the
following subroutine. It does not call |build_page|, because it is
used in at least one place where that would be a mistake.

@<Declare action...@>=
procedure append_glue;
var s:small_number; {modifier of skip command}
begin s:=cur_chr;
case s of
fil_code: cur_val:=fil_glue;
fill_code: cur_val:=fill_glue;
ss_code: cur_val:=ss_glue;
fil_neg_code: cur_val:=fil_neg_glue;
skip_code: scan_glue(glue_val);
mskip_code: scan_glue(mu_val);
end; {now |cur_val| points to the glue specification}
tail_append(new_glue(cur_val));
if s>=skip_code then
  begin decr(glue_ref_count(cur_val));
  if s>skip_code then subtype(tail):=mu_glue;
  end;
end;

@ @<Declare act...@>=
procedure append_kern;
var s:quarterword; {|subtype| of the kern node}
begin s:=cur_chr; scan_dimen(s=mu_glue,false,false);
tail_append(new_kern(cur_val)); subtype(tail):=s;
end;

@ Many of the actions related to box-making are triggered by the appearance
of braces in the input. For example, when the user says `\.{\\hbox}
\.{to} \.{100pt\{$\langle\,\hbox{hlist}\,\rangle$\}}' in vertical mode,
the information about the box size (100pt, |exactly|) is put onto |save_stack|
with a level boundary word just above it, and |cur_group:=adjusted_hbox_group|;
\TeX\ enters restricted horizontal mode to process the hlist. The right
brace eventually causes |save_stack| to be restored to its former state,
at which time the information about the box size (100pt, |exactly|) is
available once again; a box is packaged and we leave restricted horizontal
mode, appending the new box to the current list of the enclosing mode
(in this case to the current list of vertical mode), followed by any
vertical adjustments that were removed from the box by |hpack|.

The next few sections of the program are therefore concerned with the
treatment of left and right curly braces.

@ If a left brace occurs in the middle of a page or paragraph, it simply
introduces a new level of grouping, and the matching right brace will not have
such a drastic effect. Such grouping affects neither the mode nor the
current list.

@<Cases of |main_control| that build...@>=
non_math(left_brace): begin
  new_save_level(simple_group);
  eq_word_define(int_base+no_local_whatsits_code,0);
  eq_word_define(int_base+no_local_dirs_code,0);
  end;
any_mode(begin_group): begin
  new_save_level(semi_simple_group);
  eq_word_define(int_base+no_local_whatsits_code,0);
  eq_word_define(int_base+no_local_dirs_code,0);
  end;
any_mode(end_group):
  if cur_group=semi_simple_group then begin
    temp_no_whatsits:=no_local_whatsits;
    temp_no_dirs:=no_local_dirs;
    temporary_dir:=text_direction;
    if dir_level(text_dir_ptr)=cur_level then
      @<DIR: Remove from |text_dir_ptr|@>;
    unsave;
    if abs(mode)=hmode then begin
      if temp_no_dirs<>0 then begin
        @<DIR: Add local dir node@>;
        dir_dir(tail):=temporary_dir-64;
        end;
      if temp_no_whatsits<>0 then
        @<LOCAL: Add local paragraph node@>;
      end
    end
  else off_save;

@ We have to deal with errors in which braces and such things are not
properly nested. Sometimes the user makes an error of commission by
inserting an extra symbol, but sometimes the user makes an error of omission.
\TeX\ can't always tell one from the other, so it makes a guess and tries
to avoid getting into a loop.

The |off_save| routine is called when the current group code is wrong. It tries
to insert something into the user's input that will help clean off
the top level.

@<Declare act...@>=
procedure off_save;
var p,q:pointer; {inserted token}
begin if cur_group=bottom_level then
  @<Drop current token and complain that it was unmatched@>
else  begin back_input; p:=get_avail; link(temp_token_head):=p;
  print_err("Missing ");
  @<Prepare to insert a token that matches |cur_group|,
    and print what it is@>;
  print(" inserted"); ins_list(link(temp_token_head));
  help5("I've inserted something that you may have forgotten.")@/
  ("(See the <inserted text> above.)")@/
  ("With luck, this will get me unwedged. But if you")@/
  ("really didn't forget anything, try typing `2' now; then")@/
  ("my insertion and my current dilemma will both disappear.");
  error;
  end;
end;

@ At this point, |link(temp_token_head)=p|, a pointer to an empty one-word node.

@<Prepare to insert a token that matches |cur_group|...@>=
case cur_group of
semi_simple_group: begin info(p):=cs_token_flag+frozen_end_group;
  print_esc("endgroup");
@.Missing \\endgroup inserted@>
  end;
math_shift_group: begin info(p):=math_shift_token+"$"; print_char("$");
@.Missing \$ inserted@>
  end;
math_left_group: begin info(p):=cs_token_flag+frozen_right; q:=get_avail; link(p):=q;
  p:=link(p); info(p):=other_token+"."; print_esc("right.");
@.Missing \\right\hbox{.} inserted@>
@^null delimiter@>
  end;
othercases begin info(p):=right_brace_token+"}"; print_char("}");
@.Missing \} inserted@>
  end
endcases

@ @<Drop current token and complain that it was unmatched@>=
begin print_err("Extra "); print_cmd_chr(cur_cmd,cur_chr);
@.Extra x@>
help1("Things are pretty mixed up, but I think the worst is over.");@/
error;
end

@ The routine for a |right_brace| character branches into many subcases,
since a variety of things may happen, depending on |cur_group|. Some
types of groups are not supposed to be ended by a right brace; error
messages are given in hopes of pinpointing the problem. Most branches
of this routine will be filled in later, when we are ready to understand
them; meanwhile, we must prepare ourselves to deal with such errors.

@<Cases of |main_control| that build...@>=
any_mode(right_brace): handle_right_brace;

@ @<Declare the procedure called |handle_right_brace|@>=
procedure handle_right_brace;
var p,@!q:pointer; {for short-term use}
@!d:scaled; {holds |split_max_depth| in |insert_group|}
@!f:integer; {holds |floating_penalty| in |insert_group|}
begin p:=null;
case cur_group of
simple_group: begin
  temp_no_whatsits:=no_local_whatsits;
  temp_no_dirs:=no_local_dirs;
  temporary_dir:=text_direction;
  if dir_level(text_dir_ptr)=cur_level then
    @<DIR: Remove from |text_dir_ptr|@>;
  unsave;
  if abs(mode)=hmode then begin
    if temp_no_dirs<>0 then begin
      @<DIR: Add local dir node@>;
      dir_dir(tail):=temporary_dir-64;
      end;
    if temp_no_whatsits<>0 then
      @<LOCAL: Add local paragraph node@>;
    end
  end;
bottom_level: begin print_err("Too many }'s");
@.Too many \}'s@>
  help2("You've closed more groups than you opened.")@/
  ("Such booboos are generally harmless, so keep going."); error;
  end;
semi_simple_group,math_shift_group,math_left_group: extra_right_brace;
@t\4@>@<Cases of |handle_right_brace| where a |right_brace| triggers
  a delayed action@>@;
othercases confusion("rightbrace")
@:this can't happen rightbrace}{\quad rightbrace@>
endcases;
end;

@ @<Declare act...@>=
procedure extra_right_brace;
begin print_err("Extra }, or forgotten ");
@.Extra \}, or forgotten x@>
case cur_group of
semi_simple_group: print_esc("endgroup");
math_shift_group: print_char("$");
math_left_group: print_esc("right");
end;@/
help5("I've deleted a group-closing symbol because it seems to be")@/
("spurious, as in `$x}$'. But perhaps the } is legitimate and")@/
("you forgot something else, as in `\hbox{$x}'. In such cases")@/
("the way to recover is to insert both the forgotten and the")@/
("deleted material, e.g., by typing `I$}'."); error;
incr(align_state);
end;

@ Here is where we clear the parameters that are supposed to revert to their
default values after every paragraph and when internal vertical mode is entered.

@<Declare act...@>=
procedure normal_paragraph;
begin if looseness<>0 then eq_word_define(int_base+looseness_code,0);
if hang_indent<>0 then eq_word_define(dimen_base+hang_indent_code,0);
if hang_after<>1 then eq_word_define(int_base+hang_after_code,1);
if par_shape_ptr<>null then eq_define(par_shape_loc,shape_ref,null);
if inter_line_penalties_ptr<>null then
  eq_define(inter_line_penalties_loc,shape_ref,null);
end;

@ Now let's turn to the question of how \.{\\hbox} is treated. We actually
need to consider also a slightly larger context, since constructions like
`\.{\\setbox3=}\penalty0\.{\\hbox...}' and
`\.{\\leaders}\penalty0\.{\\hbox...}' and
`\.{\\lower3.8pt\\hbox...}'
are supposed to invoke quite
different actions after the box has been packaged. Conversely,
constructions like `\.{\\setbox3=}' can be followed by a variety of
different kinds of boxes, and we would like to encode such things in an
efficient way.

In other words, there are two problems: To represent the context of a box,
and to represent its type.

The first problem is solved by putting a ``context code'' on the |save_stack|,
just below the two entries that give the dimensions produced by |scan_spec|.
The context code is either a (signed) shift amount, or it is a large
integer |>=box_flag|, where |box_flag=@t$2^{30}$@>|. Codes |box_flag| through
|box_flag+biggest_reg| represent `\.{\\setbox0}' through
`\.{\\setbox}|biggest_reg|'; codes |box_flag+biggest_reg+1| through
|box_flag+2*biggest_reg| represent `\.{\\global\\setbox0}'
through `\.{\\global\\setbox}|biggest_reg|'; code |box_flag+2*number_regs|
represents `\.{\\shipout}'; and codes |box_flag+2*number_regs+1|
through |box_flag+2*number_regs+3| represent `\.{\\leaders}', `\.{\\cleaders}',
and `\.{\\xleaders}'.

The second problem is solved by giving the command code |make_box| to all
control sequences that produce a box, and by using the following |chr_code|
values to distinguish between them: |box_code|, |copy_code|, |last_box_code|,
|vsplit_code|, |vtop_code|, |vtop_code+vmode|, and |vtop_code+hmode|,
where the latter two are used denote \.{\\vbox} and \.{\\hbox}, respectively.

@d box_flag==@'10000000000 {context code for `\.{\\setbox0}'}
@d global_box_flag==(box_flag+number_regs) {context code for `\.{\\global\\setbox0}'}
@d max_global_box_flag==(global_box_flag+number_regs)
@d ship_out_flag==(max_global_box_flag+1) {context code for `\.{\\shipout}'}
@d leader_flag==ship_out_flag+1 {context code for `\.{\\leaders}'}
@d box_code=0 {|chr_code| for `\.{\\box}'}
@d copy_code=1 {|chr_code| for `\.{\\copy}'}
@d last_box_code=2 {|chr_code| for `\.{\\lastbox}'}
@d vsplit_code=3 {|chr_code| for `\.{\\vsplit}'}
@d vtop_code=4 {|chr_code| for `\.{\\vtop}'}

@<Put each...@>=
primitive_tex("moveleft",hmove,1,0);
@!@:move_left_}{\.{\\moveleft} primitive@>
primitive_tex("moveright",hmove,0,0);@/
@!@:move_right_}{\.{\\moveright} primitive@>
primitive_tex("raise",vmove,1,0);
@!@:raise_}{\.{\\raise} primitive@>
primitive_tex("lower",vmove,0,0);
@!@:lower_}{\.{\\lower} primitive@>
@#
primitive_tex("box",make_box,box_code,0);
@!@:box_}{\.{\\box} primitive@>
primitive_tex("copy",make_box,copy_code,0);
@!@:copy_}{\.{\\copy} primitive@>
primitive_tex("lastbox",make_box,last_box_code,0);
@!@:last_box_}{\.{\\lastbox} primitive@>
primitive_tex("vsplit",make_box,vsplit_code,0);
@!@:vsplit_}{\.{\\vsplit} primitive@>
primitive_tex("vtop",make_box,vtop_code,0);@/
@!@:vtop_}{\.{\\vtop} primitive@>
primitive_tex("vbox",make_box,vtop_code+vmode,0);
@!@:vbox_}{\.{\\vbox} primitive@>
primitive_tex("hbox",make_box,vtop_code+hmode,0);@/
@!@:hbox_}{\.{\\hbox} primitive@>
primitive_tex("shipout",leader_ship,a_leaders-1,0); {|ship_out_flag=leader_flag-1|}
@!@:ship_out_}{\.{\\shipout} primitive@>
primitive_tex("leaders",leader_ship,a_leaders,0);
@!@:leaders_}{\.{\\leaders} primitive@>
primitive_tex("cleaders",leader_ship,c_leaders,0);
@!@:c_leaders_}{\.{\\cleaders} primitive@>
primitive_tex("xleaders",leader_ship,x_leaders,0);
@!@:x_leaders_}{\.{\\xleaders} primitive@>;
primitive_aleph("boxdir",assign_box_dir,0,0);
@!@:box_dir}{\.{\\boxdir} primitive@>

@ Constructions that require a box are started by calling |scan_box| with
a specified context code. The |scan_box| routine verifies
that a |make_box| command comes next and then it calls |begin_box|.

@<Cases of |main_control| that build...@>=
vmode+hmove,hmode+vmove,mmode+vmove: begin t:=cur_chr;
  scan_normal_dimen;
  if t=0 then scan_box(cur_val)@+else scan_box(-cur_val);
  end;
any_mode(leader_ship): scan_box(leader_flag-a_leaders+cur_chr);
any_mode(make_box): begin_box(0);
any_mode(assign_box_dir): begin scan_register_num;
  cur_box:=box(cur_val);
  scan_optional_equals; scan_direction;
  if cur_box<>null then box_dir(cur_box):=cur_val;
  end;

@ The global variable |cur_box| will point to a newly-made box. If the box
is void, we will have |cur_box=null|. Otherwise we will have
|type(cur_box)=hlist_node| or |vlist_node| or |rule_node|; the |rule_node|
case can occur only with leaders.

@<Glob...@>=
@!cur_box:pointer; {box to be placed into its context}

@ The |box_end| procedure does the right thing with |cur_box|, if
|box_context| represents the context as explained above.

@<Declare act...@>=
procedure box_end(@!box_context:integer);
begin if box_context<box_flag then @<Append box |cur_box| to the current list,
    shifted by |box_context|@>
else if box_context<ship_out_flag then @<Store \(c)|cur_box| in a box register@>
else if cur_box<>null then begin
  if box_context>ship_out_flag then @<Append a new leader node that
      uses |cur_box|@>
  else ship_out(cur_box);
  end;
end;

@ The global variable |adjust_tail| will be non-null if and only if the
current box might include adjustments that should be appended to the
current vertical list.

@<Append box |cur_box| to the current...@>=
begin if cur_box<>null then
  begin shift_amount(cur_box):=box_context;
  if abs(mode)=vmode then
    begin
        if pre_adjust_tail <> null then begin
            if pre_adjust_head <> pre_adjust_tail then
                append_list(pre_adjust_head)(pre_adjust_tail);
            pre_adjust_tail := null;
        end;
        append_to_vlist(cur_box);
        if adjust_tail <> null then begin
            if adjust_head <> adjust_tail then
                append_list(adjust_head)(adjust_tail);
            adjust_tail := null;
        end;
    if mode>0 then begin check_filter('box'); build_page; end;
    end
  else  begin if abs(mode)=hmode then space_factor:=1000
    else cur_box:=new_sub_box(cur_box);
    vlink(tail):=cur_box; tail:=cur_box;
    end;
  end;
end

@ @<Store \(c)|cur_box| in a box register@>=
if box_context<global_box_flag then
  eq_define(box_base+box_context-box_flag,box_ref,cur_box)
else geq_define(box_base+box_context-global_box_flag,box_ref,cur_box)

@ @<Append a new leader node ...@>=
begin @<Get the next non-blank non-relax...@>;
if ((cur_cmd=hskip)and(abs(mode)<>vmode))or@|
   ((cur_cmd=vskip)and(abs(mode)=vmode)) then
  begin append_glue; subtype(tail):=box_context-(leader_flag-a_leaders);
  leader_ptr(tail):=cur_box;
  end
else  begin print_err("Leaders not followed by proper glue");
@.Leaders not followed by...@>
  help3("You should say `\leaders <box or rule><hskip or vskip>'.")@/
  ("I found the <box or rule>, but there's no suitable")@/
  ("<hskip or vskip>, so I'm ignoring these leaders."); back_error;
  flush_node_list(cur_box);
  end;
end

@ Now that we can see what eventually happens to boxes, we can consider
the first steps in their creation. The |begin_box| routine is called when
|box_context| is a context specification, |cur_chr| specifies the type of
box desired, and |cur_cmd=make_box|.

@<Declare act...@>=
procedure begin_box(@!box_context:integer);
label exit, done;
var @!p,@!q:pointer; {run through the current list}
@!k:halfword; {0 or |vmode| or |hmode|}
@!n:eight_bits; {a box number}
begin case cur_chr of
box_code: begin scan_register_num; cur_box:=box(cur_val);
  box(cur_val):=null; {the box becomes void, at the same level}
  end;
copy_code: begin scan_register_num; cur_box:=copy_node_list(box(cur_val));
  end;
last_box_code: @<If the current list ends with a box node, delete it from
  the list and make |cur_box| point to it; otherwise set |cur_box:=null|@>;
vsplit_code: @<Split off part of a vertical box, make |cur_box| point to it@>;
othercases @<Initiate the construction of an hbox or vbox, then |return|@>
endcases;@/
box_end(box_context); {in simple cases, we use the box immediately}
exit:end;

@ Note that the condition |not is_char_node(tail)| implies that |head<>tail|,
since |head| is a one-word node.

@<If the current list ends with a box node, delete it...@>=
begin cur_box:=null;
if abs(mode)=mmode then
  begin you_cant; help1("Sorry; this \lastbox will be void."); error;
  end
else if (mode=vmode)and(head=tail) then
  begin you_cant;
  help2("Sorry...I usually can't take things from the current page.")@/
    ("This \lastbox will therefore be void."); error;
  end
else  begin if not is_char_node(tail) then
    if (type(tail)=hlist_node)or(type(tail)=vlist_node) then
      @<Remove the last box, unless it's part of a discretionary@>;
  end;
end

@ @<Remove the last box...@>=
begin q:=head;
repeat p:=q;
if not is_char_node(q) then if type(q)=disc_node then
  begin
  if p=tail then goto done;
  end;
q:=vlink(p);
until q=tail;
cur_box:=tail; shift_amount(cur_box):=0;
tail:=p; vlink(p):=null;
done:end

@ Here we deal with things like `\.{\\vsplit 13 to 100pt}'.

@<Split off part of a vertical box, make |cur_box| point to it@>=
begin scan_register_num; n:=cur_val;
if not scan_keyword('to') then
@.to@>
  begin print_err("Missing `to' inserted");
@.Missing `to' inserted@>
  help2("I'm working on `\vsplit<box number> to <dimen>';")@/
  ("will look for the <dimen> next."); error;
  end;
scan_normal_dimen;
cur_box:=vsplit(n,cur_val);
end

@ Here is where we enter restricted horizontal mode or internal vertical
mode, in order to make a box.

@<Initiate the construction of an hbox or vbox, then |return|@>=
begin k:=cur_chr-vtop_code; saved(0):=box_context;
case abs(mode) of
vmode: spec_direction:=body_direction;
hmode: spec_direction:=text_direction;
mmode: spec_direction:=math_direction;
end;
if k=hmode then
  if (box_context<box_flag)and(abs(mode)=vmode) then
    scan_spec(adjusted_hbox_group,true)
  else scan_spec(hbox_group,true)
else  begin if k=vmode then scan_spec(vbox_group,true)
  else  begin scan_spec(vtop_group,true); k:=vmode;
    end;
  normal_paragraph;
  end;
push_nest; mode:=-k;
if k=vmode then
  begin prev_depth:=pdf_ignored_dimen;
  if every_vbox<>null then begin_token_list(every_vbox,every_vbox_text);
  end
else  begin space_factor:=1000;
  if every_hbox<>null then begin_token_list(every_hbox,every_hbox_text);
  end;
return;
end

@ @<Declare act...@>=
procedure scan_box(@!box_context:integer);
  {the next input should specify a box or perhaps a rule}
begin @<Get the next non-blank non-relax...@>;
if cur_cmd=make_box then begin_box(box_context)
else if (box_context>=leader_flag)and((cur_cmd=hrule)or(cur_cmd=vrule)) then
  begin cur_box:=scan_rule_spec; box_end(box_context);
  end
else  begin@t@>@;@/
  print_err("A <box> was supposed to be here");@/
@.A <box> was supposed to...@>
  help3("I was expecting to see \hbox or \vbox or \copy or \box or")@/
  ("something like that. So you might find something missing in")@/
  ("your output. But keep trying; you can fix this later."); back_error;
  end;
end;

@ When the right brace occurs at the end of an \.{\\hbox} or \.{\\vbox} or
\.{\\vtop} construction, the |package| routine comes into action. We might
also have to finish a paragraph that hasn't ended.

@<Cases of |handle...@>=
hbox_group: package(0);
adjusted_hbox_group: begin adjust_tail:=adjust_head;
    pre_adjust_tail:=pre_adjust_head; package(0);
  end;
vbox_group: begin line_break_context:=vbox_group; end_graf; package(0);
  end;
vtop_group: begin line_break_context:=vtop_group; end_graf; package(vtop_code);
  end;

@ @<Declare action...@>=
procedure package(@!c:small_number);
var h:scaled; {height of box}
@!p:pointer; {first node in a box}
@!d:scaled; {max depth}
@!grp:integer;
begin grp:=cur_group;
d:=box_max_depth; unsave; save_ptr:=save_ptr-6;
pack_direction:=saved(3);
if mode=-hmode then cur_box:=filtered_hpack(head,tail,saved(2),saved(1),grp)
else  begin cur_box:=filtered_vpackage(vlink(head),saved(2),saved(1),d,grp);
  if c=vtop_code then @<Readjust the height and depth of |cur_box|,
    for \.{\\vtop}@>;
  end;
if saved(4)<>null then
  @<DIR: Adjust back |text_dir_ptr| for |scan_spec|@>;
replace_attribute_list(cur_box, saved(5));
pop_nest; box_end(saved(0));
end;

@ The height of a `\.{\\vtop}' box is inherited from the first item on its list,
if that item is an |hlist_node|, |vlist_node|, or |rule_node|; otherwise
the \.{\\vtop} height is zero.


@<Readjust the height...@>=
begin h:=0; p:=list_ptr(cur_box);
if p<>null then if type(p)<=rule_node then h:=height(p);
depth(cur_box):=depth(cur_box)-h+height(cur_box); height(cur_box):=h;
end

@ Here is a really small patch to add a new primitive called
\.{\\quitvmode}. In vertical modes, it is identical to \.{\\indent},
but in horizontal and math modes it is really a no-op (as opposed to
\.{\\indent}, which executes the |indent_in_hmode| procedure).

A paragraph begins when horizontal-mode material occurs in vertical mode,
or when the paragraph is explicitly started by `\.{\\quitvmode}',
`\.{\\indent}' or `\.{\\noindent}'.

@<Put each...@>=
primitive_tex("indent",start_par,1,0);
@!@:indent_}{\.{\\indent} primitive@>
primitive_tex("noindent",start_par,0,0);
@!@:no_indent_}{\.{\\noindent} primitive@>
primitive_pdftex("quitvmode",start_par,2,0);
@!@:quit_vmode_}{\.{\\quitvmode} primitive@>

@ @<Cases of |main_control| that build...@>=
vmode+start_par: new_graf(cur_chr>0);
vmode+letter,vmode+other_char,vmode+char_num,vmode+char_given,
   vmode+char_ghost,
   vmode+math_shift,vmode+math_shift_cs,vmode+un_hbox,vmode+vrule,
   vmode+accent,vmode+discretionary,vmode+hskip,vmode+valign,
   vmode+ex_space,vmode+no_boundary:@t@>@;@/
  begin back_input; new_graf(true);
  end;

@ @<Declare act...@>=
procedure new_graf(@!indented:boolean);
var p,q,dir_graf_tmp:pointer;
begin prev_graf:=0;
if (mode=vmode)or(head<>tail) then begin
  tail_append(new_param_glue(par_skip_code));
  end;
push_nest; mode:=hmode; space_factor:=1000;
@<LOCAL: Add local paragraph node@>;
if indented then begin
  p:=new_null_box; box_dir(p):=par_direction;
  width(p):=par_indent;@+
  tail_append(p);
  end;
q:=tail;
dir_rover:=text_dir_ptr;
while dir_rover<>null do
  begin
  if (vlink(dir_rover)<>null) or (dir_dir(dir_rover)<>par_direction) then
    begin
    dir_graf_tmp:=new_dir(dir_dir(dir_rover));
    vlink(dir_graf_tmp):=vlink(q); vlink(q):=dir_graf_tmp;
    end;
  dir_rover:=vlink(dir_rover);
  end;
q:=head;
while vlink(q)<>null do q:=vlink(q);
tail:=q;
if every_par<>null then begin_token_list(every_par,every_par_text);
if nest_ptr=1 then begin
  check_filter('new_graf'); build_page; {put |par_skip| glue on current page}
  end;
end;

@ @<Cases of |main_control| that build...@>=
hmode+start_par,mmode+start_par: if cur_chr<>2 then indent_in_hmode;

@ @<Declare act...@>=
procedure indent_in_hmode;
var p:pointer;
begin if cur_chr>0 then {\.{\\indent}}
  begin p:=new_null_box; width(p):=par_indent;
  if abs(mode)=hmode then space_factor:=1000
  else  p:=new_sub_box(p);
  tail_append(p);
  end;
end;

@ A paragraph ends when a |par_end| command is sensed, or when we are in
horizontal mode when reaching the right brace of vertical-mode routines
like \.{\\vbox}, \.{\\insert}, or \.{\\output}.

@<Cases of |main_control| that build...@>=
vmode+par_end: begin normal_paragraph;
  if mode>0 then begin check_filter('vmode_par'); build_page; end;
  end;
hmode+par_end: begin if align_state<0 then off_save; {this tries to
    recover from an alignment that didn't end properly}
  if (mode>0) and (nest[(nest_ptr-1)].mode_field=vmode) then
          line_break_context:=bottom_level;
  end_graf; {this takes us to the enclosing mode, if |mode>0|}
  if mode=vmode then begin check_filter('hmode_par');  build_page; end;
  end;
hmode+stop,hmode+vskip,hmode+hrule,hmode+un_vbox,hmode+halign: head_for_vmode;

@ @<Declare act...@>=
procedure head_for_vmode;
begin if mode<0 then
  if cur_cmd<>hrule then off_save
  else  begin print_err("You can't use `");
    print_esc("hrule"); print("' here except with leaders");
@.You can't use \\hrule...@>
    help2("To put a horizontal rule in an hbox or an alignment,")@/
      ("you should use \leaders or \hrulefill (see The TeXbook).");
    error;
    end
else  begin back_input; cur_tok:=par_token; back_input; token_type:=inserted;
  end;
end;

@ TODO (BUG?): |dir_save| would have been set by |line_break| by means
of |post_line_break|, but this is not done right now, as it introduces
pretty heavy memory leaks. This means the current code is probably
wrong in some way that relates to in-paragraph displays.

@<Declare act...@>=
procedure end_graf;
begin if mode=hmode then
  begin if (head=tail) or (vlink(head)=tail) then pop_nest
        {null paragraphs are ignored, all contain a |local_paragraph| node}
  else line_break(false);
  if dir_save<>null then
    begin flush_node_list(dir_save); dir_save:=null;
    end;
  normal_paragraph;
  error_count:=0;
  end;
end;

@ Insertion and adjustment and mark nodes are constructed by the following
pieces of the program.

@<Cases of |main_control| that build...@>=
any_mode(insert),hmode+vadjust,mmode+vadjust: begin_insert_or_adjust;
any_mode(mark): handle_mark;

@ @<Forbidden...@>=
vmode+vadjust,

@ @<Declare act...@>=
procedure begin_insert_or_adjust;
begin if cur_cmd=vadjust then cur_val:=output_box
else  begin scan_register_num;
  if cur_val=output_box then
    begin print_err("You can't "); print_esc("insert"); print_int(output_box);
@.You can't \\insert\outputbox@>
    help1("I'm changing to \insert0; box \outputbox is special.");
    error; cur_val:=0;
    end;
  end;
saved(0) := cur_val;
if (cur_cmd = vadjust) and scan_keyword('pre') then
    saved(1) := 1
else
    saved(1) := 0;
save_ptr := save_ptr + 2;
new_save_level(insert_group); scan_left_brace; normal_paragraph;
push_nest; mode:=-vmode; prev_depth:=pdf_ignored_dimen;
end;

@ @<Cases of |handle...@>=
insert_group: begin
  line_break_context:=insert_group;
  end_graf; q:=split_top_skip; add_glue_ref(q);
  d:=split_max_depth; f:=floating_penalty; unsave; save_ptr := save_ptr - 2;
  {now |saved(0)| is the insertion number, or |output_box| for |vadjust|}
  p:=vpack(vlink(head),natural); pop_nest;
  if saved(0)<>output_box then
    begin tail_append(new_node(ins_node,saved(0)));
    height(tail):=height(p)+depth(p); ins_ptr(tail):=list_ptr(p);
    split_top_ptr(tail):=q; depth(tail):=d; float_cost(tail):=f;
    end
  else  begin tail_append(new_node(adjust_node,saved(1))); {the |subtype| is used for |adjust_pre|}
    adjust_ptr(tail):=list_ptr(p); delete_glue_ref(q);
    end;
  list_ptr(p):=null; flush_node(p);
  if nest_ptr=0 then begin check_filter('insert'); build_page; end;
  end;
output_group: @<Resume the page builder...@>;

@ I've renamed the |make_mark| procedure to this, because if the
current chr code is 1, then the actual command was \.{\\clearmarks},
which does not generate a mark node but instead destroys the current
mark tokenlists.

@<Declare act...@>=
procedure handle_mark;
var p:pointer; {new node}
@!c:halfword; {the mark class}
begin if cur_chr=clear_marks_code then begin
    scan_mark_num; c:=cur_val;
    delete_top_mark(c); delete_bot_mark(c); delete_first_mark(c);
    delete_split_first_mark(c); delete_split_bot_mark(c);
  end
else begin
if cur_chr=0 then c:=0
else begin scan_mark_num; c:=cur_val;
  if c > biggest_used_mark then biggest_used_mark := c;
  end;
p:=scan_toks(false,true);
p:=new_node(mark_node,0); {the |subtype| is not used}
mark_class(p):=c;
mark_ptr(p):=def_ref; vlink(tail):=p; tail:=p;
end;
end;

@ Penalty nodes get into a list via the |break_penalty| command.
@^penalties@>

@<Cases of |main_control| that build...@>=
any_mode(break_penalty): append_penalty;

@ @<Declare action...@>=
procedure append_penalty;
begin scan_int; tail_append(new_penalty(cur_val));
if mode=vmode then begin check_filter('penalty'); build_page; end;
end;

@ The |remove_item| command removes a penalty, kern, or glue node if it
appears at the tail of the current list, using a brute-force linear scan.
Like \.{\\lastbox}, this command is not allowed in vertical mode (except
internal vertical mode), since the current list in vertical mode is sent
to the page builder.  But if we happen to be able to implement it in
vertical mode, we do.

@<Cases of |main_control| that build...@>=
any_mode(remove_item): delete_last;

@ When |delete_last| is called, |cur_chr| is the |type| of node that
will be deleted, if present.

@<Declare action...@>=
procedure delete_last;
label exit;
var @!p,@!q:pointer; {run through the current list}
begin if (mode=vmode)and(tail=head) then
  @<Apologize for inability to do the operation now,
    unless \.{\\unskip} follows non-glue@>
else  begin if not is_char_node(tail) then if type(tail)=cur_chr then
    begin q:=head;
    repeat p:=q;
    if not is_char_node(q) then if type(q)=disc_node then
      begin
      if p=tail then return;
      end;
    q:=vlink(p);
    until q=tail;
    vlink(p):=null; flush_node_list(tail); tail:=p;
    end;
  end;
exit:end;

@ @<Apologize for inability to do the operation...@>=
begin if (cur_chr<>glue_node)or(last_glue<>max_halfword) then
  begin you_cant;
  help2("Sorry...I usually can't take things from the current page.")@/
    ("Try `I\vskip-\lastskip' instead.");
  if cur_chr=kern_node then help_line[0]:=
    ("Try `I\kern-\lastkern' instead.")
  else if cur_chr<>glue_node then help_line[0]:=@|
    ("Perhaps you can make the output routine do it.");
  error;
  end;
end

@ @<Put each...@>=
primitive_tex("unpenalty",remove_item,penalty_node,0);@/
@!@:un_penalty_}{\.{\\unpenalty} primitive@>
primitive_tex("unkern",remove_item,kern_node,0);@/
@!@:un_kern_}{\.{\\unkern} primitive@>
primitive_tex("unskip",remove_item,glue_node,0);@/
@!@:un_skip_}{\.{\\unskip} primitive@>
primitive_tex("unhbox",un_hbox,box_code,0);@/
@!@:un_hbox_}{\.{\\unhbox} primitive@>
primitive_tex("unhcopy",un_hbox,copy_code,0);@/
@!@:un_hcopy_}{\.{\\unhcopy} primitive@>
primitive_tex("unvbox",un_vbox,box_code,0);@/
@!@:un_vbox_}{\.{\\unvbox} primitive@>
primitive_tex("unvcopy",un_vbox,copy_code,0);@/
@!@:un_vcopy_}{\.{\\unvcopy} primitive@>

@ The |un_hbox| and |un_vbox| commands unwrap one of the |number_regs| current boxes.

@<Cases of |main_control| that build...@>=
vmode+un_vbox,hmode+un_hbox,mmode+un_hbox: unpackage;

@ @<Declare act...@>=
procedure unpackage;
label done, exit;
var p:pointer; {the box}
    r: pointer; {to remove marginal kern nodes}
@!c:box_code..copy_code; {should we copy?}
@!s:pointer; {for varmem assignment }
begin if cur_chr>copy_code then @<Handle saved items and |goto done|@>;
c:=cur_chr; scan_register_num; p:=box(cur_val);
if p=null then return;
if (abs(mode)=mmode)or((abs(mode)=vmode)and(type(p)<>vlist_node))or@|
   ((abs(mode)=hmode)and(type(p)<>hlist_node)) then
  begin print_err("Incompatible list can't be unboxed");
@.Incompatible list...@>
  help3("Sorry, Pandora. (You sneaky devil.)")@/
  ("I refuse to unbox an \hbox in vertical mode or vice versa.")@/
  ("And I can't open any boxes in math mode.");@/
  error; return;
  end;
if c=copy_code then begin s:=copy_node_list(list_ptr(p)); vlink(tail):=s; end
else  begin vlink(tail):=list_ptr(p); box(cur_val):=null;
  list_ptr(p):=null; flush_node(p);
  end;
done:
while vlink(tail) <> null do begin
    r := vlink(tail);
    if not is_char_node(r) and (type(r) = margin_kern_node) then begin
        vlink(tail) := vlink(r);
        flush_node(r);
    end;
    tail:=vlink(tail);
end;
exit:end;

@ @<Forbidden...@>=vmode+ital_corr,

@ Italic corrections are converted to kern nodes when the |ital_corr| command
follows a character. In math mode the same effect is achieved by appending
a kern of zero here, since italic corrections are supplied later.

@<Cases of |main_control| that build...@>=
hmode+ital_corr: append_italic_correction;
mmode+ital_corr: tail_append(new_kern(0));

@ @<Declare act...@>=
procedure append_italic_correction;
label exit;
var p:pointer; {|char_node| at the tail of the current list}
@!f:internal_font_number; {the font in the |char_node|}
begin if tail<>head then
  begin if is_char_node(tail) then p:=tail
  else return;
  f:=font(p);
  tail_append(new_kern(char_italic(f,character(p))));
  subtype(tail):=explicit;
  end;
exit:end;

@ Discretionary nodes are easy in the common case `\.{\\-}', but in the
general case we must process three braces full of items.

There are four subtypes of discretionaries, but only the first two are
generated by primitive commands.

@d discretionary_disc=0
@d explicit_disc=1

@<Put each...@>=
primitive_tex("-",discretionary,explicit_disc,0);
@!@:Single-character primitives -}{\quad\.{\\-}@>
primitive_tex("discretionary",discretionary,discretionary_disc,0);
@!@:discretionary_}{\.{\\discretionary} primitive@>
primitive_omega("localleftbox",assign_local_box,0,0);
@!@:assign_local_box}{\.{\\localleftbox} primitive@>
primitive_omega("localrightbox",assign_local_box,1,0);
@!@:assign_local_box}{\.{\\localrightbox} primitive@>

@ @<Cases of |main_control| that build...@>=
hmode+discretionary,mmode+discretionary: append_discretionary;
any_mode(assign_local_box): append_local_box(cur_chr);

@ The space factor does not change when we append a discretionary node,
but it starts out as 1000 in the subsidiary lists.

@<Declare act...@>=
procedure append_local_box(kind:integer);
begin
incr(save_ptr); saved(-1):=kind; new_save_level(local_box_group);
scan_left_brace; push_nest; mode:=-hmode; space_factor:=1000;
end;

procedure append_discretionary;
var c:integer;
begin tail_append(new_disc);
subtype(tail):=cur_chr;
if cur_chr=explicit_disc then begin
    c:=get_pre_hyphen_char(cur_lang);
    if c<>0 then begin
          vlink(pre_break(tail)):=new_char(cur_font,c);
      alink(vlink(pre_break(tail))):=pre_break(tail);
          tlink(pre_break(tail)):=vlink(pre_break(tail));
      end;
    c:=get_post_hyphen_char(cur_lang);
    if c<>0 then begin
       vlink(post_break(tail)):=new_char(cur_font,c);
       alink(vlink(post_break(tail))):=post_break(tail);
       tlink(post_break(tail)):=vlink(post_break(tail));
       end;
    end
else  begin incr(save_ptr); saved(-1):=0; new_save_level(disc_group);
  scan_left_brace; push_nest; mode:=-hmode; space_factor:=1000;
  end;
end;

@ The three discretionary lists are constructed somewhat as if they were
hboxes. A~subroutine called |build_discretionary| handles the transitions.
(This is sort of fun.)

@<Cases of |handle...@>=
disc_group: build_discretionary;
local_box_group: build_local_box;

@ @<Declare act...@>=
procedure build_local_box;
var p:pointer;
    kind:integer;
begin
unsave;
kind:=saved(-1);
decr(save_ptr);
p:=vlink(head); pop_nest;
if p<>null then
  p:=hpack(p,natural);
if kind=0 then
    eq_define(local_left_box_base,box_ref,p)
else
  eq_define(local_right_box_base,box_ref,p);
if abs(mode)=hmode then
  @<LOCAL: Add local paragraph node@>;
eq_word_define(int_base+no_local_whatsits_code,no_local_whatsits+1);
end;

procedure build_discretionary;
label done,exit;
var p,@!q:pointer; {for link manipulation}
@!n:integer; {length of discretionary list}
begin unsave;
@<Prune the current list, if necessary, until it contains only
  |char_node|, |kern_node|, |hlist_node|, |vlist_node| and
  |rule_node| items; set |n| to the length of the list,
  and set |q| to the list's tail@>;
p:=vlink(head); pop_nest;
case saved(-1) of
0: if (n>0) then begin
   vlink(pre_break(tail)):=p;
   alink(p):=pre_break(tail);
   tlink(pre_break(tail)):=q;
   end;
1: if (n>0) then begin
   vlink(post_break(tail)):=p;
   alink(p):=post_break(tail);
   tlink(post_break(tail)):=q;
   end;
2:@<Attach list |p| to the current list, and record its length;
  then finish up and |return|@>;
end; {there are no other cases}
incr(saved(-1)); new_save_level(disc_group); scan_left_brace;
push_nest; mode:=-hmode; space_factor:=1000;
exit:end;

@ @<Attach list |p| to the current...@>=
begin if (n>0)and(abs(mode)=mmode) then
  begin print_err("Illegal math "); print_esc("discretionary");
@.Illegal math \\disc...@>
  help2("Sorry: The third part of a discretionary break must be")@/
  ("empty, in math formulas. I had to delete your third part.");
  flush_node_list(p); error;
  end
else begin
  if (n>0) then begin
    vlink(no_break(tail)):=p;
    alink(p):=no_break(tail);
    tlink(no_break(tail)):=q;
    end;
  end;
decr(save_ptr); return;
end

@ During this loop, |p=vlink(q)| and there are |n| items preceding |p|.

@<Prune the current list, if necessary...@>=
q:=head; p:=vlink(q); n:=0;
while p<>null do
  begin if not is_char_node(p) then
    if type(p)>rule_node then if type(p)<>kern_node then
      begin print_err("Improper discretionary list");
@.Improper discretionary list@>
      help1("Discretionary lists must contain only boxes and kerns.");@/
      error;
      begin_diagnostic;
      print_nl("The following discretionary sublist has been deleted:");
@.The following...deleted@>
      show_box(p);
      end_diagnostic(true);
      flush_node_list(p); vlink(q):=null; goto done;
      end;
  alink(p):=q; q:=p; p:=vlink(q); incr(n);
  end;
done:

@ We need only one more thing to complete the horizontal mode routines, namely
the \.{\\accent} primitive.

@<Cases of |main_control| that build...@>=
hmode+accent: make_accent;

@ The positioning of accents is straightforward but tedious. Given an accent
of width |a|, designed for characters of height |x| and slant |s|;
and given a character of width |w|, height |h|, and slant |t|: We will shift
the accent down by |x-h|, and we will insert kern nodes that have the effect of
centering the accent over the character and shifting the accent to the
right by $\delta={1\over2}(w-a)+h\cdot t-x\cdot s$.  If either character is
absent from the font, we will simply use the other, without shifting.

@<Declare act...@>=
procedure make_accent;
var s,@!t: real; {amount of slant}
@!p,@!q,@!r:pointer; {character, box, and kern nodes}
@!f:internal_font_number; {relevant font}
@!a,@!h,@!x,@!w,@!delta:scaled; {heights and widths, as explained above}
begin scan_char_num; f:=cur_font; p:=new_glyph(f,cur_val);
if p<>null then
  begin x:=x_height(f); s:=slant(f)/float_constant(65536);
@^real division@>
  a:=glyph_width(p);@/
  do_assignments;@/
  @<Create a character node |q| for the next character,
    but set |q:=null| if problems arise@>;
  if q<>null then @<Append the accent with appropriate kerns,
      then set |p:=q|@>;
  vlink(tail):=p; tail:=p; space_factor:=1000;
  end;
end;

@ @<Create a character node |q| for the next...@>=
q:=null; f:=cur_font;
if (cur_cmd=letter)or(cur_cmd=other_char)or(cur_cmd=char_given) then
  q:=new_glyph(f,cur_chr)
else if cur_cmd=char_num then
  begin scan_char_num; q:=new_glyph(f,cur_val);
  end
else back_input

@ The kern nodes appended here must be distinguished from other kerns, lest
they be wiped away by the hyphenation algorithm or by a previous line break.

The two kerns are computed with (machine-dependent) |real| arithmetic, but
their sum is machine-independent; the net effect is machine-independent,
because the user cannot remove these nodes nor access them via \.{\\lastkern}.

@<Append the accent with appropriate kerns...@>=
begin t:=slant(f)/float_constant(65536);
@^real division@>
w:=glyph_width(q);
h:=glyph_height(q);
if h<>x then {the accent must be shifted up or down}
  begin p:=hpack(p,natural); shift_amount(p):=x-h;
  end;
delta:=round((w-a)/float_constant(2)+h*t-x*s);
@^real multiplication@>
@^real addition@>
r:=new_kern(delta); subtype(r):=acc_kern; vlink(tail):=r; vlink(r):=p;
tail:=new_kern(-a-delta); subtype(tail):=acc_kern; vlink(p):=tail; p:=q;
end

@ When `\.{\\cr}' or `\.{\\span}' or a tab mark comes through the scanner
into |main_control|, it might be that the user has foolishly inserted
one of them into something that has nothing to do with alignment. But it is
far more likely that a left brace or right brace has been omitted, since
|get_next| takes actions appropriate to alignment only when `\.{\\cr}'
or `\.{\\span}' or tab marks occur with |align_state=0|. The following
program attempts to make an appropriate recovery.

@<Cases of |main_control| that build...@>=
any_mode(car_ret), any_mode(tab_mark): align_error;
any_mode(no_align): no_align_error;
any_mode(omit): omit_error;

@ @<Declare act...@>=
procedure align_error;
begin if abs(align_state)>2 then
  @<Express consternation over the fact that no alignment is in progress@>
else  begin back_input;
  if align_state<0 then
    begin print_err("Missing { inserted");
@.Missing \{ inserted@>
    incr(align_state); cur_tok:=left_brace_token+"{";
    end
  else  begin print_err("Missing } inserted");
@.Missing \} inserted@>
    decr(align_state); cur_tok:=right_brace_token+"}";
    end;
  help3("I've put in what seems to be necessary to fix")@/
    ("the current column of the current alignment.")@/
    ("Try to go on, since this might almost work."); ins_error;
  end;
end;

@ @<Express consternation...@>=
begin print_err("Misplaced "); print_cmd_chr(cur_cmd,cur_chr);
@.Misplaced \&@>
@.Misplaced \\span@>
@.Misplaced \\cr@>
if cur_tok=tab_token+"&" then
  begin help6("I can't figure out why you would want to use a tab mark")@/
  ("here. If you just want an ampersand, the remedy is")@/
  ("simple: Just type `I\&' now. But if some right brace")@/
  ("up above has ended a previous alignment prematurely,")@/
  ("you're probably due for more error messages, and you")@/
  ("might try typing `S' now just to see what is salvageable.");
  end
else  begin help5("I can't figure out why you would want to use a tab mark")@/
  ("or \cr or \span just now. If something like a right brace")@/
  ("up above has ended a previous alignment prematurely,")@/
  ("you're probably due for more error messages, and you")@/
  ("might try typing `S' now just to see what is salvageable.");
  end;
error;
end

@ The help messages here contain a little white lie, since \.{\\noalign}
and \.{\\omit} are allowed also after `\.{\\noalign\{...\}}'.

@<Declare act...@>=
procedure no_align_error;
begin print_err("Misplaced "); print_esc("noalign");
@.Misplaced \\noalign@>
help2("I expect to see \noalign only after the \cr of")@/
  ("an alignment. Proceed, and I'll ignore this case."); error;
end;
procedure omit_error;
begin print_err("Misplaced "); print_esc("omit");
@.Misplaced \\omit@>
help2("I expect to see \omit only after tab marks or the \cr of")@/
  ("an alignment. Proceed, and I'll ignore this case."); error;
end;

@ We've now covered most of the abuses of \.{\\halign} and \.{\\valign}.
Let's take a look at what happens when they are used correctly.

@<Cases of |main_control| that build...@>=
vmode+halign,hmode+valign:init_align;
mmode+halign: if privileged then begin
  if cur_group=math_shift_group then init_align
  else off_save;
  end;
vmode+endv,hmode+endv: do_endv;

@ An |align_group| code is supposed to remain on the |save_stack|
during an entire alignment, until |fin_align| removes it.

A devious user might force an |endv| command to occur just about anywhere;
we must defeat such hacks.

@<Declare act...@>=
procedure do_endv;
begin base_ptr:=input_ptr; input_stack[base_ptr]:=cur_input;
while (input_stack[base_ptr].index_field<>v_template) and
      (input_stack[base_ptr].loc_field=null) and
      (input_stack[base_ptr].state_field=token_list) do decr(base_ptr);
if (input_stack[base_ptr].index_field<>v_template) or
      (input_stack[base_ptr].loc_field<>null) or
      (input_stack[base_ptr].state_field<>token_list) then
  fatal_error("(interwoven alignment preambles are not allowed)");
@.interwoven alignment preambles...@>
 if cur_group=align_group then
  begin line_break_context:=align_group; end_graf;
  if fin_col then fin_row;
  end
else off_save;
end;

@ @<Cases of |handle_right_brace|...@>=
align_group: begin back_input; cur_tok:=cs_token_flag+frozen_cr;
  print_err("Missing "); print_esc("cr"); print(" inserted");
@.Missing \\cr inserted@>
  help1("I'm guessing that you meant to end an alignment here.");
  ins_error;
  end;

@ @<Cases of |handle_right_brace|...@>=
no_align_group: begin line_break_context:=no_align_group; end_graf; unsave; align_peek;
  end;

@ Finally, \.{\\endcsname} is not supposed to get through to |main_control|.

@<Cases of |main_control| that build...@>=
any_mode(end_cs_name): cs_error;

@ @<Declare act...@>=
procedure cs_error;
begin print_err("Extra "); print_esc("endcsname");
@.Extra \\endcsname@>
help1("I'm ignoring this, since I wasn't doing a \csname.");
error;
end;

@* \[48] Building math lists.

@ Almost all of this section is now in C, see |math.c|. Let here are just
the definitions of the primitives and the infrastructure hooks into |main_control|,
|print_cmd_chr| and |handle_right_brace|.

@<Put each...@>=
primitive_luatex("Ustartmath",math_shift_cs,text_style,0);
@!@:math_shift_cs_}{\.{\\Ustartmath} primitive@>
primitive_luatex("Ustopmath",math_shift_cs,cramped_text_style,0);
@!@:math_shift_cs_}{\.{\\Ustopmath} primitive@>
primitive_luatex("Ustartdisplaymath",math_shift_cs,display_style,0);
@!@:math_shift_cs_}{\.{\\Ustartdisplaymath} primitive@>
primitive_luatex("Ustopdisplaymath",math_shift_cs,cramped_display_style,0);
@!@:math_shift_cs_}{\.{\\Ustopdisplaymath} primitive@>

@

@<Cases of |main_control| that build...@>=
hmode+math_shift, hmode+math_shift_cs:init_math;
mmode+eq_no: if privileged then begin
  if cur_group=math_shift_group then start_eq_no
  else off_save;
  end;

@ @<Put each...@>=
primitive_tex("eqno",eq_no,0,0);
@!@:eq_no_}{\.{\\eqno} primitive@>
primitive_tex("leqno",eq_no,1,0);
@!@:leq_no_}{\.{\\leqno} primitive@>

@ @<Forbidden...@>=non_math(eq_no),

@ @<Cases of |main_control| that build...@>=
mmode+left_brace: math_left_brace;
mmode+letter,mmode+other_char,mmode+char_given:
  set_math_char(get_math_code(cur_chr));
mmode+char_num: begin scan_char_num; cur_chr:=cur_val;
  set_math_char(get_math_code(cur_chr));
  end;
mmode+math_char_num: begin
   if cur_chr=0 then
     mval := scan_mathchar(tex_mathcode)
   else if cur_chr=1 then
     mval := scan_mathchar(aleph_mathcode)
   else if cur_chr=2 then
     mval := scan_mathchar(xetex_mathcode)
   else
     mval := scan_mathchar(xetexnum_mathcode);
  set_math_char(mval);
  end;
mmode+math_given: begin
  mval := mathchar_from_integer(cur_chr,tex_mathcode);
  set_math_char(mval);
  end;
mmode+omath_given: begin
  mval := mathchar_from_integer(cur_chr,aleph_mathcode);
  set_math_char(mval);
  end;
mmode+xmath_given: begin
  mval := mathchar_from_integer(cur_chr,xetex_mathcode);
  set_math_char(mval);
  end;
mmode+delim_num: begin
  if cur_chr=0 then
    mval := scan_delimiter_as_mathchar(tex_mathcode)
  else if cur_chr=1 then
    mval := scan_delimiter_as_mathchar(aleph_mathcode)
  else
    mval := scan_delimiter_as_mathchar(xetex_mathcode);
  set_math_char(mval);
  end;

@ Primitive math operators like \.{\\mathop} and \.{\\underline} are given
the command code |math_comp|, supplemented by the noad type that they
generate.

@<Put each...@>=
primitive_tex("mathord",math_comp,ord_noad_type,0);
@!@:math_ord_}{\.{\\mathord} primitive@>
primitive_tex("mathop",math_comp,op_noad_type_normal,0);
@!@:math_op_}{\.{\\mathop} primitive@>
primitive_tex("mathbin",math_comp,bin_noad_type,0);
@!@:math_bin_}{\.{\\mathbin} primitive@>
primitive_tex("mathrel",math_comp,rel_noad_type,0);
@!@:math_rel_}{\.{\\mathrel} primitive@>
primitive_tex("mathopen",math_comp,open_noad_type,0);
@!@:math_open_}{\.{\\mathopen} primitive@>
primitive_tex("mathclose",math_comp,close_noad_type,0);
@!@:math_close_}{\.{\\mathclose} primitive@>
primitive_tex("mathpunct",math_comp,punct_noad_type,0);
@!@:math_punct_}{\.{\\mathpunct} primitive@>
primitive_tex("mathinner",math_comp,inner_noad_type,0);
@!@:math_inner_}{\.{\\mathinner} primitive@>
primitive_tex("underline",math_comp,under_noad_type,0);
@!@:underline_}{\.{\\underline} primitive@>
primitive_tex("overline",math_comp,over_noad_type,0);@/
@!@:overline_}{\.{\\overline} primitive@>
primitive_tex("displaylimits",limit_switch,op_noad_type_normal,0);
@!@:display_limits_}{\.{\\displaylimits} primitive@>
primitive_tex("limits",limit_switch,op_noad_type_limits,0);
@!@:limits_}{\.{\\limits} primitive@>
primitive_tex("nolimits",limit_switch,op_noad_type_no_limits,0);
@!@:no_limits_}{\.{\\nolimits} primitive@>

@ @<Cases of |main_control| that build...@>=
mmode+math_comp: math_math_comp;
mmode+limit_switch: math_limit_switch;
mmode+radical: math_radical;
mmode+accent,mmode+math_accent:math_ac;
mmode+vcenter: begin scan_spec(vcenter_group,false); normal_paragraph;
  push_nest; mode:=-vmode; prev_depth:=pdf_ignored_dimen;
  if every_vbox<>null then begin_token_list(every_vbox,every_vbox_text);
  end;

@ @<Cases of |handle...@>=
vcenter_group: begin line_break_context:=vcenter_group; end_graf; unsave; save_ptr:=save_ptr-2;
  p:=vpack(vlink(head),saved(1),saved(0)); pop_nest;
  p:=math_vcenter_group(p);
  tail_append(p);
  end;

@ The routine that inserts a |style_node| holds no surprises.

@<Put each...@>=
primitive_tex("displaystyle",math_style,display_style,0);
@!@:display_style_}{\.{\\displaystyle} primitive@>
primitive_tex("textstyle",math_style,text_style,0);
@!@:text_style_}{\.{\\textstyle} primitive@>
primitive_tex("scriptstyle",math_style,script_style,0);
@!@:script_style_}{\.{\\scriptstyle} primitive@>
primitive_tex("scriptscriptstyle",math_style,script_script_style,0);
@!@:script_script_style_}{\.{\\scriptscriptstyle} primitive@>
primitive_luatex("crampeddisplaystyle",math_style,cramped_display_style,0);
@!@:cramped_display_style_}{\.{\\crampeddisplaystyle} primitive@>
primitive_luatex("crampedtextstyle",math_style,cramped_text_style,0);
@!@:cramped_text_style_}{\.{\\crampedtextstyle} primitive@>
primitive_luatex("crampedscriptstyle",math_style,cramped_script_style,0);
@!@:cramped_script_style_}{\.{\\crampedscriptstyle} primitive@>
primitive_luatex("crampedscriptscriptstyle",math_style,cramped_script_script_style,0);
@!@:cramped_script_script_style_}{\.{\\crampedscriptscriptstyle} primitive@>

@ @<Cases of |main_control| that build...@>=
mmode+math_style: tail_append(new_style(cur_chr));
mmode+non_script: begin tail_append(new_glue(zero_glue));
  subtype(tail):=cond_math_glue;
  end;
mmode+math_choice: if cur_chr=0 then append_choices else setup_math_style;

@ @<Cases of |handle_right_brace|...@>=
math_choice_group: build_choices;

@ Here are two primives for explicit super- or subscript choice.

@<Put each...@>=
primitive_luatex("Usuperscript",super_sub_script,sup_mark,sup_mark);
@!@:super_sub_script_}{\.{\\Usuperscript} primitive@>
primitive_luatex("Usubscript",super_sub_script,sub_mark,sup_mark);
@!@:super_sub_script_}{\.{\\Usubscript} primitive@>

@ @<Cases of |main_control| that build...@>=
mmode+sub_mark,mmode+sup_mark,mmode+super_sub_script: sub_sup;

@
@d above_code=0 { `\.{\\above}' }
@d over_code=1 { `\.{\\over}' }
@d atop_code=2 { `\.{\\atop}' }
@d delimited_code=3 { `\.{\\abovewithdelims}', etc.}

@<Put each...@>=
primitive_tex("above",above,above_code,0);@/
@!@:above_}{\.{\\above} primitive@>
primitive_tex("over",above,over_code,0);@/
@!@:over_}{\.{\\over} primitive@>
primitive_tex("atop",above,atop_code,0);@/
@!@:atop_}{\.{\\atop} primitive@>
primitive_tex("abovewithdelims",above,delimited_code+above_code,0);@/
@!@:above_with_delims_}{\.{\\abovewithdelims} primitive@>
primitive_tex("overwithdelims",above,delimited_code+over_code,0);@/
@!@:over_with_delims_}{\.{\\overwithdelims} primitive@>
primitive_tex("atopwithdelims",above,delimited_code+atop_code,0);
@!@:atop_with_delims_}{\.{\\atopwithdelims} primitive@>

@ @<Cases of |main_control| that build...@>=
mmode+above: math_fraction;

@ @<Cases of |handle...@>=
math_group: close_math_group(p);

@

@<Put each...@>=
primitive_tex("left",left_right,left_noad_side,0);
@!@:left_}{\.{\\left} primitive@>
primitive_tex("right",left_right,right_noad_side,0);
@!@:right_}{\.{\\right} primitive@>
primitive_tex("middle",left_right,middle_noad_side,0);
@!@:middle_}{\.{\\middle} primitive@>
text(frozen_right):="right"; eqtb[frozen_right]:=eqtb[cur_val];

@ @<Cases of |main_control| that build...@>=
mmode+left_right: math_left_right;

@ Here is the only way out of math mode.

@<Cases of |main_control| that build...@>=
mmode+math_shift,mmode+math_shift_cs: if cur_group=math_shift_group then after_math
  else off_save;


@* \[49] Mode-independent processing.
The long |main_control| procedure has now been fully specified, except for
certain activities that are independent of the current mode. These activities
do not change the current vlist or hlist or mlist; if they change anything,
it is the value of a parameter or the meaning of a control sequence.

Assignments to values in |eqtb| can be global or local. Furthermore, a
control sequence can be defined to be `\.{\\long}', `\.{\\protected}',
or `\.{\\outer}', and it might or might not be expanded. The prefixes
`\.{\\global}', `\.{\\long}', `\.{\\protected}',
and `\.{\\outer}' can occur in any order. Therefore we assign binary numeric
codes, making it possible to accumulate the union of all specified prefixes
by adding the corresponding codes.  (\PASCAL's |set| operations could also
have been used.)

@<Put each...@>=
primitive_tex("long",prefix,1,0);
@!@:long_}{\.{\\long} primitive@>
primitive_tex("outer",prefix,2,0);
@!@:outer_}{\.{\\outer} primitive@>
primitive_tex("global",prefix,4,0);
@!@:global_}{\.{\\global} primitive@>
primitive_tex("def",def,0,0);
@!@:def_}{\.{\\def} primitive@>
primitive_tex("gdef",def,1,0);
@!@:gdef_}{\.{\\gdef} primitive@>
primitive_tex("edef",def,2,0);
@!@:edef_}{\.{\\edef} primitive@>
primitive_tex("xdef",def,3,0);
@!@:xdef_}{\.{\\xdef} primitive@>

@ Every prefix, and every command code that might or might not be prefixed,
calls the action procedure |prefixed_command|. This routine accumulates
a sequence of prefixes until coming to a non-prefix, then it carries out
the command.

@<Cases of |main_control| that don't...@>=
any_mode(toks_register),
any_mode(assign_toks),
any_mode(assign_int),
any_mode(assign_attr),
any_mode(assign_dir),
any_mode(assign_dimen),
any_mode(assign_glue),
any_mode(assign_mu_glue),
any_mode(assign_font_dimen),
any_mode(assign_font_int),
any_mode(set_aux),
any_mode(set_prev_graf),
any_mode(set_page_dimen),
any_mode(set_page_int),
any_mode(set_box_dimen),
any_mode(set_tex_shape),
any_mode(set_etex_shape),
any_mode(def_char_code),
any_mode(def_del_code),
any_mode(extdef_math_code),
any_mode(extdef_del_code),
any_mode(def_family),
any_mode(set_math_param),
any_mode(set_font),
any_mode(def_font),
any_mode(letterspace_font),
any_mode(pdf_copy_font),
any_mode(register),
any_mode(advance),
any_mode(multiply),
any_mode(divide),
any_mode(prefix),
any_mode(let),
any_mode(shorthand_def),
any_mode(read_to_cs),
any_mode(def),
any_mode(set_box),
any_mode(hyph_data),
any_mode(set_interaction),
any_mode(set_ocp),
any_mode(def_ocp),
any_mode(set_ocp_list),
any_mode(def_ocp_list),
any_mode(clear_ocp_lists),
any_mode(push_ocp_list),
any_mode(pop_ocp_list),
any_mode(ocp_list_op),
any_mode(ocp_trace_level) : prefixed_command;

@ If the user says, e.g., `\.{\\global\\global}', the redundancy is
silently accepted.

@<Declare act...@>=
@t\4@>@<Declare subprocedures for |prefixed_command|@>@t@>@;@/
procedure prefixed_command;
label done,exit;
var a:small_number; {accumulated prefix codes so far}
@!f:internal_font_number; {identifies a font}
@!j:halfword; {index into a \.{\\parshape} specification}
@!p,@!q:pointer; {for temporary short-term use}
@!n:integer; {ditto}
@!e:boolean; {should a definition be expanded? or was \.{\\let} not done?}
@!mval:mathcodeval; {for handling of \.{\\mathchardef}s}
begin a:=0;
while cur_cmd=prefix do
  begin if not odd(a div cur_chr) then a:=a+cur_chr;
  @<Get the next non-blank non-relax...@>;
  if cur_cmd<=max_non_prefixed_command then
    @<Discard erroneous prefixes and |return|@>;
  if tracing_commands>2 then show_cur_cmd_chr;
  end;
@<Discard the prefixes \.{\\long} and \.{\\outer} if they are irrelevant@>;
@<Adjust \(f)for the setting of \.{\\globaldefs}@>;
case cur_cmd of
@t\4@>@<Assignments@>@;
othercases confusion("prefix")
@:this can't happen prefix}{\quad prefix@>
endcases;
done: @<Insert a token saved by \.{\\afterassignment}, if any@>;
exit:end;

@ @<Discard erroneous...@>=
begin print_err("You can't use a prefix with `");
@.You can't use a prefix with x@>
print_cmd_chr(cur_cmd,cur_chr); print_char("'");
help1("I'll pretend you didn't say \long or \outer or \global or \protected.");
back_error; return;
end

@ @<Discard the prefixes...@>=
if a>=8 then
  begin j:=protected_token; a:=a-8;
  end
else j:=0;
if (cur_cmd<>def)and((a mod 4<>0)or(j<>0)) then
  begin print_err("You can't use `"); print_esc("long"); print("' or `");
  print_esc("outer"); print("' with `");
@.You can't use \\long...@>
  print_cmd_chr(cur_cmd,cur_chr); print_char("'");
  help1("I'll pretend you didn't say \long or \outer here.");
  error;
  end

@ The previous routine does not have to adjust |a| so that |a mod 4=0|,
since the following routines test for the \.{\\global} prefix as follows.

@d global==(a>=4)
@d define(#)==begin if global then geq_define(#)@+else eq_define(#); end
@d word_define(#)==begin if global then geq_word_define(#)@+else eq_word_define(#); end
@d define_lc_code(#)==begin if global
   then set_lc_code(#,level_one)@+else set_lc_code(#,cur_level); end
@d define_uc_code(#)==begin if global
   then set_uc_code(#,level_one)@+else set_uc_code(#,cur_level); end
@d define_sf_code(#)==begin if global
   then set_sf_code(#,level_one)@+else set_sf_code(#,cur_level); end
@d define_cat_code(#)==begin if global
   then set_cat_code(cat_code_table,#,level_one)@+else set_cat_code(cat_code_table,#,cur_level); end
@d define_fam_fnt(#)==begin if global
   then def_fam_fnt(#,level_one)@+else def_fam_fnt(#,cur_level); end
@d define_math_param(#)==begin if global
   then def_math_param(#,level_one)@+else def_math_param(#,cur_level); end


@<Adjust \(f)for the setting of \.{\\globaldefs}@>=
if global_defs<>0 then begin
  if global_defs<0 then
    begin if global then a:=a-4;
    end
  else  begin if not global then a:=a+4;
    end;
  end

@ When a control sequence is to be defined, by \.{\\def} or \.{\\let} or
something similar, the |get_r_token| routine will substitute a special
control sequence for a token that is not redefinable.

@<Declare subprocedures for |prefixed_command|@>=
procedure get_r_token;
label restart;
begin restart: repeat get_token;
until cur_tok<>space_token;
if (cur_cs=0)or(cur_cs>frozen_control_sequence) then
  begin print_err("Missing control sequence inserted");
@.Missing control...@>
  help5("Please don't say `\def cs{...}', say `\def\cs{...}'.")@/
  ("I've inserted an inaccessible control sequence so that your")@/
  ("definition will be completed without mixing me up too badly.")@/
  ("You can recover graciously from this error, if you're")@/
  ("careful; see exercise 27.2 in The TeXbook.");
@:TeXbook}{\sl The \TeX book@>
  if cur_cs=0 then back_input;
  cur_tok:=cs_token_flag+frozen_protection; ins_error; goto restart;
  end;
end;

@ @<Initialize table entries...@>=
text(frozen_protection):="inaccessible";

@ Assignments from Lua need helpers.

@p function is_int_assign(cmd:halfword):boolean;
begin
  is_int_assign := (cmd=assign_int);
end;
function is_dim_assign(cmd:halfword):boolean;
begin
  is_dim_assign := (cmd=assign_dimen);
end;

@ @<Declare subprocedures for |prefixed_command|@>=
procedure assign_internal_value(a:small_number;p:halfword;cur_val:integer);
var  n:halfword;
begin
if (p>=int_base)and(p<attribute_base) then begin
  if p=(int_base+cat_code_table_code) then begin
    if valid_catcode_table(cur_val) then begin
      if cur_val<>cat_code_table then
        word_define(p,cur_val);
      end
    else begin
      print_err("Invalid \catcode table");
      help2("You can only switch to a \catcode table that is initialized")
           ("using \savecatcodetable or \initcatcodetable, or to table 0");
      error;
      end;
    end
  else if (p=(int_base+output_box_code)and((cur_val>65535)or(cur_val<0))) then begin
    print_err("Invalid \outputbox");
    help1("The value for \outputbox has to be between 0 and 65535.");
    error;
    end
  else if ((p=new_line_char)and((cur_val>127)or(cur_val<0))) then begin
    print_err("Invalid \newlinechar");
    help1("The value for \newlinechar has to be between 0 and 127.");
    error;
    end
  else if p=end_line_char then begin
    if (cur_val<0)or(cur_val>biggest_char) then
      word_define(p,-1)
    else
      word_define(p,13);
    end
  else
   word_define(p,cur_val);
{If we are defining subparagraph penalty levels while we are
in hmode, then we put out a whatsit immediately, otherwise
we leave it alone.  This mechanism might not be sufficiently
powerful, and some other algorithm, searching down the stack,
might be necessary.  Good first step.}
  if (abs(mode)=hmode) and
     ((p=(int_base+local_inter_line_penalty_code)) or
      (p=(int_base+local_broken_penalty_code))) then begin
    @<LOCAL: Add local paragraph node@>;
    eq_word_define(int_base+no_local_whatsits_code,no_local_whatsits+1);
    end;
  if p=int_base+language_code then word_define(int_base+cur_lang_code,cur_val);
  end
else if (p>=dimen_base)and(p<eqtb_size) then begin
  if p=(dimen_base+page_left_offset_code) then begin
    n:=cur_val - one_true_inch;
    word_define(dimen_base+h_offset_code, n);
    end
  else if p=(dimen_base+h_offset_code) then begin
    n:=cur_val + one_true_inch;
    word_define(dimen_base+page_left_offset_code, n);
    end
  else if p=(dimen_base+page_top_offset_code) then begin
    n:=cur_val - one_true_inch;
    word_define(dimen_base+v_offset_code, n);
    end
  else if p=(dimen_base+v_offset_code) then begin
    n:=cur_val + one_true_inch;
    word_define(dimen_base+page_top_offset_code, n);
    end;
  word_define(p,cur_val);
  end
else
  confusion("assign internal value");
end;


@ Here's an example of the way many of the following routines operate.
(Unfortunately, they aren't all as simple as this.)

@<Assignments@>=
set_font: define(cur_font_loc,data,cur_chr);

@ When a |def| command has been scanned,
|cur_chr| is odd if the definition is supposed to be global, and
|cur_chr>=2| if the definition is supposed to be expanded.

@<Assignments@>=
def: begin if odd(cur_chr)and not global and(global_defs>=0) then a:=a+4;
  e:=(cur_chr>=2); get_r_token; p:=cur_cs;
  q:=scan_toks(true,e);
  if j<>0 then
    begin q:=get_avail; info(q):=j; link(q):=link(def_ref);
    link(def_ref):=q;
    end;
  define(p,call+(a mod 4),def_ref);
  end;

@ Both \.{\\let} and \.{\\futurelet} share the command code |let|.

@<Put each...@>=
primitive_tex("let",let,normal,0);@/
@!@:let_}{\.{\\let} primitive@>
primitive_tex("futurelet",let,normal+1,0);@/
@!@:future_let_}{\.{\\futurelet} primitive@>

@ @<Assignments@>=
let:  begin n:=cur_chr;
  get_r_token; p:=cur_cs;
  if n=normal then
    begin repeat get_token;
    until cur_cmd<>spacer;
    if cur_tok=other_token+"=" then
      begin get_token;
      if cur_cmd=spacer then get_token;
      end;
    end
  else  begin get_token; q:=cur_tok; get_token; back_input;
    cur_tok:=q; back_input; {look ahead, then back up}
    end; {note that |back_input| doesn't affect |cur_cmd|, |cur_chr|}
  if cur_cmd>=call then add_token_ref(cur_chr);
  define(p,cur_cmd,cur_chr);
  end;

@ A \.{\\chardef} creates a control sequence whose |cmd| is |char_given|;
a \.{\\mathchardef} creates a control sequence whose |cmd| is |math_given|;
and the corresponding |chr| is the character code or math code. A \.{\\countdef}
or \.{\\dimendef} or \.{\\skipdef} or \.{\\muskipdef} creates a control
sequence whose |cmd| is |assign_int| or \dots\ or |assign_mu_glue|, and the
corresponding |chr| is the |eqtb| location of the internal register in question.

@d char_def_code=0 {|shorthand_def| for \.{\\chardef}}
@d math_char_def_code=1 {|shorthand_def| for \.{\\mathchardef}}
@d omath_char_def_code=2 {|shorthand_def| for \.{\\omathchardef}}
@d xmath_char_def_code=3 {|shorthand_def| for \.{\\Umathchardef}}
@d count_def_code=4 {|shorthand_def| for \.{\\countdef}}
@d attribute_def_code=5 {|shorthand_def| for \.{\\attributedef}}
@d dimen_def_code=6 {|shorthand_def| for \.{\\dimendef}}
@d skip_def_code=7 {|shorthand_def| for \.{\\skipdef}}
@d mu_skip_def_code=8 {|shorthand_def| for \.{\\muskipdef}}
@d toks_def_code=9 {|shorthand_def| for \.{\\toksdef}}

@<Put each...@>=
primitive_tex("chardef",shorthand_def,char_def_code,0);@/
@!@:char_def_}{\.{\\chardef} primitive@>
primitive_tex("mathchardef",shorthand_def,math_char_def_code,0);@/
@!@:math_char_def_}{\.{\\mathchardef} primitive@>
primitive_omega("omathchardef",shorthand_def,omath_char_def_code,0);@/
@!@:math_char_def_}{\.{\\omathchardef} primitive@>
primitive_luatex("Umathchardef",shorthand_def,xmath_char_def_code,0);@/
@!@:math_char_def_}{\.{\\Umathchardef} primitive@>
primitive_tex("countdef",shorthand_def,count_def_code,0);@/
@!@:count_def_}{\.{\\countdef} primitive@>
primitive_luatex("attributedef",shorthand_def,attribute_def_code,0);@/
@!@:attribute_def_}{\.{\\attributedef} primitive@>
primitive_tex("dimendef",shorthand_def,dimen_def_code,0);@/
@!@:dimen_def_}{\.{\\dimendef} primitive@>
primitive_tex("skipdef",shorthand_def,skip_def_code,0);@/
@!@:skip_def_}{\.{\\skipdef} primitive@>
primitive_tex("muskipdef",shorthand_def,mu_skip_def_code,0);@/
@!@:mu_skip_def_}{\.{\\muskipdef} primitive@>
primitive_tex("toksdef",shorthand_def,toks_def_code,0);@/
@!@:toks_def_}{\.{\\toksdef} primitive@>

@ We temporarily define |p| to be |relax|, so that an occurrence of |p|
while scanning the definition will simply stop the scanning instead of
producing an ``undefined control sequence'' error or expanding the
previous meaning.  This allows, for instance, `\.{\\chardef\\foo=123\\foo}'.

@<Assignments@>=
shorthand_def: begin n:=cur_chr; get_r_token; p:=cur_cs;
  define(p,relax,too_big_char); scan_optional_equals;
  case n of
  char_def_code: begin scan_char_num; define(p,char_given,cur_val);
    end;
  math_char_def_code: begin
    mval:=scan_mathchar(tex_mathcode);
    cur_val:=(mval.class_value*16+mval.family_value)*256+mval.character_value;
    define(p,math_given,cur_val);
    end;
  omath_char_def_code: begin
    mval:=scan_mathchar(aleph_mathcode);
    cur_val:=(mval.class_value*256+mval.family_value)*65536+mval.character_value;
    define(p,omath_given,cur_val);
    end;
  xmath_char_def_code: begin
    mval:=scan_mathchar(xetex_mathcode);
    cur_val:=(mval.class_value+(8*mval.family_value))*(65536*32)+mval.character_value;
    define(p,xmath_given,cur_val);
    end;
  othercases begin scan_register_num;
    case n of
    count_def_code: define(p,assign_int,count_base+cur_val);
    attribute_def_code: define(p,assign_attr,attribute_base+cur_val);
    dimen_def_code: define(p,assign_dimen,scaled_base+cur_val);
    skip_def_code: define(p,assign_glue,skip_base+cur_val);
    mu_skip_def_code: define(p,assign_mu_glue,mu_skip_base+cur_val);
    toks_def_code: define(p,assign_toks,toks_base+cur_val);
    end; {there are no other cases}
    end
  endcases;
  end;

@ @<Assignments@>=
read_to_cs: begin j:=cur_chr; scan_int; n:=cur_val;
  if not scan_keyword('to') then
@.to@>
    begin print_err("Missing `to' inserted");
@.Missing `to'...@>
    help2("You should have said `\read<number> to \cs'.")@/
    ("I'm going to look for the \cs now."); error;
    end;
  get_r_token;
  p:=cur_cs; read_toks(n,p,j); define(p,call,cur_val);
  end;

@ The token-list parameters, \.{\\output} and \.{\\everypar}, etc., receive
their values in the following way. (For safety's sake, we place an
enclosing pair of braces around an \.{\\output} list.)

@<Assignments@>=
toks_register,assign_toks: begin q:=cur_cs;
  if cur_cmd=toks_register then
    begin scan_register_num; p:=toks_base+cur_val;
    end
  else p:=cur_chr; {|p=every_par_loc| or |output_routine_loc| or \dots}
  scan_optional_equals;
  @<Get the next non-blank non-relax non-call token@>;
  if cur_cmd<>left_brace then @<If the right-hand side is a token parameter
      or token register, finish the assignment and |goto done|@>;
  back_input; cur_cs:=q; q:=scan_toks(false,false);
  if link(def_ref)=null then {empty list: revert to the default}
    begin define(p,undefined_cs,null); free_avail(def_ref);
    end
  else  begin if p=output_routine_loc then {enclose in curlies}
      begin p:=get_avail; link(q):=p; p:=output_routine_loc;
      q:=link(q);info(q):=right_brace_token+"}";
      q:=get_avail;
      info(q):=left_brace_token+"{";
      link(q):=link(def_ref); link(def_ref):=q;
      end;
    define(p,call,def_ref);
    end;
  end;

@ @<If the right-hand side is a token parameter...@>=
begin if cur_cmd=toks_register then
  begin scan_register_num; cur_cmd:=assign_toks; cur_chr:=toks_base+cur_val;
  end;
if cur_cmd=assign_toks then
  begin q:=equiv(cur_chr);
  if q=null then define(p,undefined_cs,null)
  else  begin add_token_ref(q); define(p,call,q);
    end;
  goto done;
  end;
end

@ Similar routines are used to assign values to the numeric parameters.

@<Assignments@>=
assign_int: begin p:=cur_chr; scan_optional_equals; scan_int;
   assign_internal_value(a,p,cur_val);
   end;
assign_attr: begin p:=cur_chr; scan_optional_equals; scan_int;
  if (p-attribute_base)>max_used_attr then max_used_attr:=(p-attribute_base);
  attr_list_cache:=cache_disabled;
  word_define(p,cur_val); end;
assign_dir: begin
  @<DIR: Assign direction codes@>
  end;
assign_dimen: begin p:=cur_chr; scan_optional_equals;
  scan_normal_dimen; assign_internal_value(a,p,cur_val);
  end;
assign_glue,assign_mu_glue: begin p:=cur_chr; n:=cur_cmd; scan_optional_equals;
  if n=assign_mu_glue then scan_glue(mu_val)@+else scan_glue(glue_val);
  trap_zero_glue;
  define(p,glue_ref,cur_val);
  end;

@ When a glue register or parameter becomes zero, it will always point to
|zero_glue| because of the following procedure. (Exception: The tabskip
glue isn't trapped while preambles are being scanned.)

@<Declare subprocedures for |prefixed_command|@>=
procedure trap_zero_glue;
begin if (width(cur_val)=0)and(stretch(cur_val)=0)and(shrink(cur_val)=0) then
  begin add_glue_ref(zero_glue);
  delete_glue_ref(cur_val); cur_val:=zero_glue;
  end;
end;

@ The various character code tables are changed by the |def_code| commands,
and the font families are declared by |def_family|.

@<Put each...@>=
primitive_tex("catcode",def_char_code,cat_code_base,cat_code_base);
@!@:cat_code_}{\.{\\catcode} primitive@>
primitive_tex("mathcode",def_char_code,math_code_base,cat_code_base);
@!@:math_code_}{\.{\\mathcode} primitive@>
primitive_tex("lccode",def_char_code,lc_code_base,cat_code_base);
@!@:lc_code_}{\.{\\lccode} primitive@>
primitive_tex("uccode",def_char_code,uc_code_base,cat_code_base);
@!@:uc_code_}{\.{\\uccode} primitive@>
primitive_tex("sfcode",def_char_code,sf_code_base,cat_code_base);
@!@:sf_code_}{\.{\\sfcode} primitive@>
primitive_tex("delcode",def_del_code,del_code_base,del_code_base);
@!@:del_code_}{\.{\\delcode} primitive@>
primitive_tex("textfont",def_family,text_size,0);
@!@:text_font_}{\.{\\textfont} primitive@>
primitive_tex("scriptfont",def_family,script_size,0);
@!@:script_font_}{\.{\\scriptfont} primitive@>
primitive_tex("scriptscriptfont",def_family,script_script_size,0);
@!@:script_script_font_}{\.{\\scriptscriptfont} primitive@>
primitive_luatex("Umathquad",             set_math_param, math_param_quad,0);
primitive_luatex("Umathaxis",             set_math_param, math_param_axis,0);
primitive_luatex("Umathoperatorsize",     set_math_param, math_param_operator_size,0);
primitive_luatex("Umathoverbarkern",      set_math_param, math_param_overbar_kern,0);
primitive_luatex("Umathoverbarrule",      set_math_param, math_param_overbar_rule,0);
primitive_luatex("Umathoverbarvgap",      set_math_param, math_param_overbar_vgap,0);
primitive_luatex("Umathunderbarkern",     set_math_param, math_param_underbar_kern,0);
primitive_luatex("Umathunderbarrule",     set_math_param, math_param_underbar_rule,0);
primitive_luatex("Umathunderbarvgap",     set_math_param, math_param_underbar_vgap,0);
primitive_luatex("Umathradicalkern",      set_math_param, math_param_radical_kern,0);
primitive_luatex("Umathradicalrule",      set_math_param, math_param_radical_rule,0);
primitive_luatex("Umathradicalvgap",      set_math_param, math_param_radical_vgap,0);
primitive_luatex("Umathradicaldegreebefore",set_math_param, math_param_radical_degree_before,0);
primitive_luatex("Umathradicaldegreeafter", set_math_param, math_param_radical_degree_after,0);
primitive_luatex("Umathradicaldegreeraise", set_math_param, math_param_radical_degree_raise,0);
primitive_luatex("Umathstackvgap",        set_math_param, math_param_stack_vgap,0);
primitive_luatex("Umathstacknumup",       set_math_param, math_param_stack_num_up,0);
primitive_luatex("Umathstackdenomdown",   set_math_param, math_param_stack_denom_down,0);
primitive_luatex("Umathfractionrule",     set_math_param, math_param_fraction_rule,0);
primitive_luatex("Umathfractionnumvgap",  set_math_param, math_param_fraction_num_vgap,0);
primitive_luatex("Umathfractionnumup",    set_math_param, math_param_fraction_num_up,0);
primitive_luatex("Umathfractiondenomvgap",set_math_param, math_param_fraction_denom_vgap,0);
primitive_luatex("Umathfractiondenomdown",set_math_param, math_param_fraction_denom_down,0);
primitive_luatex("Umathfractiondelsize",  set_math_param, math_param_fraction_del_size,0);
primitive_luatex("Umathlimitabovevgap",   set_math_param, math_param_limit_above_vgap,0);
primitive_luatex("Umathlimitabovebgap",   set_math_param, math_param_limit_above_bgap,0);
primitive_luatex("Umathlimitabovekern",   set_math_param, math_param_limit_above_kern,0);
primitive_luatex("Umathlimitdownvgap",    set_math_param, math_param_limit_below_vgap,0);
primitive_luatex("Umathlimitdownbgap",    set_math_param, math_param_limit_below_bgap,0);
primitive_luatex("Umathlimitdownkern",    set_math_param, math_param_limit_below_kern,0);
primitive_luatex("Umathunderdelimitervgap", set_math_param, math_param_under_delimiter_vgap,0);
primitive_luatex("Umathunderdelimiterbgap", set_math_param, math_param_under_delimiter_bgap,0);
primitive_luatex("Umathoverdelimitervgap",set_math_param, math_param_over_delimiter_vgap,0);
primitive_luatex("Umathoverdelimiterbgap",set_math_param, math_param_over_delimiter_bgap,0);
primitive_luatex("Umathsubshiftdrop",     set_math_param, math_param_sub_shift_drop,0);
primitive_luatex("Umathsupshiftdrop",     set_math_param, math_param_sup_shift_drop,0);
primitive_luatex("Umathsubshiftdown",     set_math_param, math_param_sub_shift_down,0);
primitive_luatex("Umathsubsupshiftdown",  set_math_param, math_param_sub_sup_shift_down,0);
primitive_luatex("Umathsubtopmax",        set_math_param, math_param_sub_top_max,0);
primitive_luatex("Umathsupshiftup",       set_math_param, math_param_sup_shift_up,0);
primitive_luatex("Umathsupbottommin",     set_math_param, math_param_sup_bottom_min,0);
primitive_luatex("Umathsupsubbottommax",  set_math_param, math_param_sup_sub_bottom_max,0);
primitive_luatex("Umathsubsupvgap",       set_math_param, math_param_subsup_vgap,0);
primitive_luatex("Umathspaceafterscript", set_math_param, math_param_space_after_script,0);
primitive_luatex("Umathconnectoroverlapmin", set_math_param, math_param_connector_overlap_min,0);
primitive_luatex("Umathordordspacing",    set_math_param, math_param_ord_ord_spacing,0);
primitive_luatex("Umathordopspacing",     set_math_param, math_param_ord_op_spacing,0);
primitive_luatex("Umathordbinspacing",    set_math_param, math_param_ord_bin_spacing,0);
primitive_luatex("Umathordrelspacing",    set_math_param, math_param_ord_rel_spacing,0);
primitive_luatex("Umathordopenspacing",   set_math_param, math_param_ord_open_spacing,0);
primitive_luatex("Umathordclosespacing",  set_math_param, math_param_ord_close_spacing,0);
primitive_luatex("Umathordpunctspacing",  set_math_param, math_param_ord_punct_spacing,0);
primitive_luatex("Umathordinnerspacing",  set_math_param, math_param_ord_inner_spacing,0);
primitive_luatex("Umathopordspacing",     set_math_param, math_param_op_ord_spacing,0);
primitive_luatex("Umathopopspacing",      set_math_param, math_param_op_op_spacing,0);
primitive_luatex("Umathopbinspacing",     set_math_param, math_param_op_bin_spacing,0);
primitive_luatex("Umathoprelspacing",     set_math_param, math_param_op_rel_spacing,0);
primitive_luatex("Umathopopenspacing",    set_math_param, math_param_op_open_spacing,0);
primitive_luatex("Umathopclosespacing",   set_math_param, math_param_op_close_spacing,0);
primitive_luatex("Umathoppunctspacing",   set_math_param, math_param_op_punct_spacing,0);
primitive_luatex("Umathopinnerspacing",   set_math_param, math_param_op_inner_spacing,0);
primitive_luatex("Umathbinordspacing",    set_math_param, math_param_bin_ord_spacing,0);
primitive_luatex("Umathbinopspacing",     set_math_param, math_param_bin_op_spacing,0);
primitive_luatex("Umathbinbinspacing",    set_math_param, math_param_bin_bin_spacing,0);
primitive_luatex("Umathbinrelspacing",    set_math_param, math_param_bin_rel_spacing,0);
primitive_luatex("Umathbinopenspacing",   set_math_param, math_param_bin_open_spacing,0);
primitive_luatex("Umathbinclosespacing",  set_math_param, math_param_bin_close_spacing,0);
primitive_luatex("Umathbinpunctspacing",  set_math_param, math_param_bin_punct_spacing,0);
primitive_luatex("Umathbininnerspacing",  set_math_param, math_param_bin_inner_spacing,0);
primitive_luatex("Umathrelordspacing",    set_math_param, math_param_rel_ord_spacing,0);
primitive_luatex("Umathrelopspacing",     set_math_param, math_param_rel_op_spacing,0);
primitive_luatex("Umathrelbinspacing",    set_math_param, math_param_rel_bin_spacing,0);
primitive_luatex("Umathrelrelspacing",    set_math_param, math_param_rel_rel_spacing,0);
primitive_luatex("Umathrelopenspacing",   set_math_param, math_param_rel_open_spacing,0);
primitive_luatex("Umathrelclosespacing",  set_math_param, math_param_rel_close_spacing,0);
primitive_luatex("Umathrelpunctspacing",  set_math_param, math_param_rel_punct_spacing,0);
primitive_luatex("Umathrelinnerspacing",  set_math_param, math_param_rel_inner_spacing,0);
primitive_luatex("Umathopenordspacing",   set_math_param, math_param_open_ord_spacing,0);
primitive_luatex("Umathopenopspacing",    set_math_param, math_param_open_op_spacing,0);
primitive_luatex("Umathopenbinspacing",   set_math_param, math_param_open_bin_spacing,0);
primitive_luatex("Umathopenrelspacing",   set_math_param, math_param_open_rel_spacing,0);
primitive_luatex("Umathopenopenspacing",  set_math_param, math_param_open_open_spacing,0);
primitive_luatex("Umathopenclosespacing", set_math_param, math_param_open_close_spacing,0);
primitive_luatex("Umathopenpunctspacing", set_math_param, math_param_open_punct_spacing,0);
primitive_luatex("Umathopeninnerspacing", set_math_param, math_param_open_inner_spacing,0);
primitive_luatex("Umathcloseordspacing",  set_math_param, math_param_close_ord_spacing,0);
primitive_luatex("Umathcloseopspacing",   set_math_param, math_param_close_op_spacing,0);
primitive_luatex("Umathclosebinspacing",  set_math_param, math_param_close_bin_spacing,0);
primitive_luatex("Umathcloserelspacing",  set_math_param, math_param_close_rel_spacing,0);
primitive_luatex("Umathcloseopenspacing", set_math_param, math_param_close_open_spacing,0);
primitive_luatex("Umathcloseclosespacing",set_math_param, math_param_close_close_spacing,0);
primitive_luatex("Umathclosepunctspacing",set_math_param, math_param_close_punct_spacing,0);
primitive_luatex("Umathcloseinnerspacing",set_math_param, math_param_close_inner_spacing,0);
primitive_luatex("Umathpunctordspacing",  set_math_param, math_param_punct_ord_spacing,0);
primitive_luatex("Umathpunctopspacing",   set_math_param, math_param_punct_op_spacing,0);
primitive_luatex("Umathpunctbinspacing",  set_math_param, math_param_punct_bin_spacing,0);
primitive_luatex("Umathpunctrelspacing",  set_math_param, math_param_punct_rel_spacing,0);
primitive_luatex("Umathpunctopenspacing", set_math_param, math_param_punct_open_spacing,0);
primitive_luatex("Umathpunctclosespacing",set_math_param, math_param_punct_close_spacing,0);
primitive_luatex("Umathpunctpunctspacing",set_math_param, math_param_punct_punct_spacing,0);
primitive_luatex("Umathpunctinnerspacing",set_math_param, math_param_punct_inner_spacing,0);
primitive_luatex("Umathinnerordspacing",  set_math_param, math_param_inner_ord_spacing,0);
primitive_luatex("Umathinneropspacing",   set_math_param, math_param_inner_op_spacing,0);
primitive_luatex("Umathinnerbinspacing",  set_math_param, math_param_inner_bin_spacing,0);
primitive_luatex("Umathinnerrelspacing",  set_math_param, math_param_inner_rel_spacing,0);
primitive_luatex("Umathinneropenspacing", set_math_param, math_param_inner_open_spacing,0);
primitive_luatex("Umathinnerclosespacing",set_math_param, math_param_inner_close_spacing,0);
primitive_luatex("Umathinnerpunctspacing",set_math_param, math_param_inner_punct_spacing,0);
primitive_luatex("Umathinnerinnerspacing",set_math_param, math_param_inner_inner_spacing,0);
primitive_omega("omathcode",extdef_math_code,math_code_base,math_code_base);
@!@:math_code_}{\.{\\omathcode} primitive@>
primitive_omega("odelcode",extdef_del_code,del_code_base,del_code_base);
@!@:del_code_}{\.{\\odelcode} primitive@>
primitive_luatex("Umathcode",extdef_math_code,math_code_base+1,math_code_base);
@!@:math_code_}{\.{\\Umathcode} primitive@>
primitive_luatex("Udelcode",extdef_del_code,del_code_base+1,del_code_base);
@!@:del_code_}{\.{\\Udelcode} primitive@>
primitive_luatex("Umathcodenum",extdef_math_code,math_code_base+2,math_code_base);
@!@:math_code_}{\.{\\Umathcodenum} primitive@>
primitive_luatex("Udelcodenum",extdef_del_code,del_code_base+2,del_code_base);
@!@:del_code_}{\.{\\Udelcodenum} primitive@>


@ The different types of code values have different legal ranges; the
following program is careful to check each case properly.

@d check_def_code(#)== if ((cur_val<0)and(p<#))or(cur_val>n) then
      begin print_err("Invalid code ("); print_int(cur_val);
      if p<# then print("), should be in the range 0..")
      else print("), should be at most ");
      print_int(n);
      help1("I'm going to use 0 instead of that illegal code value.");@/
      error; cur_val:=0;
     end
@.Invalid code@>


@<Assignments@>=
def_char_code,def_del_code: begin
  @<Let |n| be the largest legal code value, based on |cur_chr|@>;
  p:=cur_chr;
  if cur_chr=math_code_base then begin
    if global then cur_val1:=level_one else cur_val1:=cur_level;
    scan_extdef_math_code(cur_val1,tex_mathcode);
    end
  else if cur_chr=lc_code_base then begin
    scan_char_num; p:= cur_val;
    scan_optional_equals;
    scan_int;
    check_def_code(lc_code_base);
    define_lc_code(p,cur_val);
    end
  else if cur_chr=uc_code_base then begin
    scan_char_num; p:= cur_val;
    scan_optional_equals;
    scan_int;
    check_def_code(uc_code_base);
    define_uc_code(p,cur_val);
    end
  else if cur_chr=sf_code_base then begin
    scan_char_num; p:= cur_val;
    scan_optional_equals;
    scan_int;
    check_def_code(sf_code_base);
    define_sf_code(p,cur_val);
    end
  else if cur_chr=cat_code_base then begin
    scan_char_num; p:= cur_val;
    scan_optional_equals;
    scan_int;
    check_def_code(cat_code_base);
    define_cat_code(p,cur_val);
    end
  else if cur_chr=del_code_base then begin
    if global then cur_val1:=level_one else cur_val1:=cur_level;
    scan_extdef_del_code(cur_val1,tex_mathcode);
    end;
  end;
extdef_math_code, extdef_del_code: begin
  if global then cur_val1:=level_one else cur_val1:=cur_level;
  if cur_chr=math_code_base  then
    scan_extdef_math_code(cur_val1,aleph_mathcode)
  else if cur_chr=math_code_base+1 then
    scan_extdef_math_code(cur_val1,xetex_mathcode)
  else if cur_chr=math_code_base+2 then
    scan_extdef_math_code(cur_val1,xetexnum_mathcode)
  else if cur_chr=del_code_base  then
    scan_extdef_del_code(cur_val1,aleph_mathcode)
  else if cur_chr=del_code_base+1  then
    scan_extdef_del_code(cur_val1,xetex_mathcode)
  else if cur_chr=del_code_base+2  then
    scan_extdef_del_code(cur_val1,xetexnum_mathcode);
  end;


@ @<Let |n| be the largest...@>=
if cur_chr=cat_code_base then n:=max_char_code
else if cur_chr=lc_code_base then n:=biggest_char
else if cur_chr=uc_code_base then n:=biggest_char
else if cur_chr=sf_code_base then n:=@'77777
else n:=biggest_char

@ @<Assignments@>=
def_family: begin p:=cur_chr; scan_math_family_int; cur_val1:=cur_val;
  scan_optional_equals; scan_font_ident;
  define_fam_fnt(cur_val1,p,cur_val);
  end;
set_math_param: begin p:=cur_chr; get_token;
   if cur_cmd<>math_style then begin
   print_err("Missing math style, treated as \displaystyle");
@.Missing number...@>
    help1("A style should have been here; I inserted `\displaystyle'.");
    cur_val1:=display_style;
    back_error;
    end
  else
    cur_val1:=cur_chr;
  scan_optional_equals;
  if p<math_param_first_mu_glue then begin
    if p=math_param_radical_degree_raise then
       scan_int
    else
       scan_dimen(false, false, false);
    end
  else begin
    scan_glue(mu_val); trap_zero_glue;
    if cur_val=thin_mu_skip then cur_val:=thin_mu_skip_code
    else if cur_val=med_mu_skip then cur_val:=med_mu_skip_code
    else if cur_val=thick_mu_skip then cur_val:=thick_mu_skip_code
    end;
  define_math_param(p,cur_val1,cur_val);
  end;

@ Next we consider changes to \TeX's numeric registers.

@<Assignments@>=
register,advance,multiply,divide: do_register_command(a);

@ We use the fact that |register<advance<multiply<divide|.

@<Declare subprocedures for |prefixed_command|@>=
procedure do_register_command(@!a:small_number);
label found,exit;
var l,@!q,@!r,@!s:pointer; {for list manipulation}
@!p:int_val..mu_val; {type of register involved}
begin q:=cur_cmd;
@<Compute the register location |l| and its type |p|; but |return| if invalid@>;
if q=register then scan_optional_equals
else if scan_keyword('by') then do_nothing; {optional `\.{by}'}
@.by@>
arith_error:=false;
if q<multiply then @<Compute result of |register| or
    |advance|, put it in |cur_val|@>
else @<Compute result of |multiply| or |divide|, put it in |cur_val|@>;
if arith_error then
  begin print_err("Arithmetic overflow");
@.Arithmetic overflow@>
  help2("I can't carry out that multiplication or division,")@/
    ("since the result is out of range.");
  if p>=glue_val then delete_glue_ref(cur_val);
  error; return;
  end;
if p<glue_val then begin
   if p=attr_val then begin
     if (l-attribute_base)>max_used_attr then max_used_attr:=(l-attribute_base);
     attr_list_cache:=cache_disabled;
     end;
  if (p=int_val) or (p=dimen_val) then
    assign_internal_value(a,l,cur_val)
  else
    word_define(l,cur_val);
  end
else  begin trap_zero_glue; define(l,glue_ref,cur_val);
  end;
exit: end;

@ Here we use the fact that the consecutive codes |int_val..mu_val| and
|assign_int..assign_mu_glue| correspond to each other nicely.

@<Compute the register location |l| and its type |p|...@>=
begin l:=0;
if q<>register then
  begin get_x_token;
  if (cur_cmd>=assign_int)and(cur_cmd<=assign_mu_glue) then
    begin l:=cur_chr; p:=cur_cmd-assign_int; goto found;
    end;
  if cur_cmd<>register then
    begin print_err("You can't use `"); print_cmd_chr(cur_cmd,cur_chr);
@.You can't use x after ...@>
    print("' after "); print_cmd_chr(q,0);
    help1("I'm forgetting what you said and not changing anything.");
    error; return;
    end;
  end;
p:=cur_chr; scan_register_num;
case p of
int_val: l:=cur_val+count_base;
attr_val: l:=cur_val+attribute_base;
dimen_val: l:=cur_val+scaled_base;
glue_val: l:=cur_val+skip_base;
mu_val: l:=cur_val+mu_skip_base;
end; {there are no other cases}
end;
found:

@ @<Compute result of |register| or |advance|...@>=
if p<glue_val then
  begin if (p=int_val) or (p=attr_val) then scan_int@+else scan_normal_dimen;
  if q=advance then cur_val:=cur_val+eqtb[l].int;
  end
else  begin scan_glue(p);
  if q=advance then @<Compute the sum of two glue specs@>;
  end

@ @<Compute the sum of two glue specs@>=
begin q:=new_spec(cur_val); r:=equiv(l);
delete_glue_ref(cur_val);
width(q):=width(q)+width(r);
if stretch(q)=0 then stretch_order(q):=normal;
if stretch_order(q)=stretch_order(r) then stretch(q):=stretch(q)+stretch(r)
else if (stretch_order(q)<stretch_order(r))and(stretch(r)<>0) then
  begin stretch(q):=stretch(r); stretch_order(q):=stretch_order(r);
  end;
if shrink(q)=0 then shrink_order(q):=normal;
if shrink_order(q)=shrink_order(r) then shrink(q):=shrink(q)+shrink(r)
else if (shrink_order(q)<shrink_order(r))and(shrink(r)<>0) then
  begin shrink(q):=shrink(r); shrink_order(q):=shrink_order(r);
  end;
cur_val:=q;
end

@ @<Compute result of |multiply| or |divide|...@>=
begin scan_int;
if p<glue_val then
  if q=multiply then
    if (p=int_val)or(p=attr_val) then cur_val:=mult_integers(eqtb[l].int,cur_val)
    else cur_val:=nx_plus_y(eqtb[l].int,cur_val,0)
  else cur_val:=x_over_n(eqtb[l].int,cur_val)
else  begin s:=equiv(l); r:=new_spec(s);
  if q=multiply then
    begin width(r):=nx_plus_y(width(s),cur_val,0);
    stretch(r):=nx_plus_y(stretch(s),cur_val,0);
    shrink(r):=nx_plus_y(shrink(s),cur_val,0);
    end
  else  begin width(r):=x_over_n(width(s),cur_val);
    stretch(r):=x_over_n(stretch(s),cur_val);
    shrink(r):=x_over_n(shrink(s),cur_val);
    end;
  cur_val:=r;
  end;
end

@ The processing of boxes is somewhat different, because we may need
to scan and create an entire box before we actually change the value of the old
one.

@<Assignments@>=
set_box: begin scan_register_num;
  if global then n:=global_box_flag+cur_val@+else n:=box_flag+cur_val;
  scan_optional_equals;
  if set_box_allowed then scan_box(n)
  else begin print_err("Improper "); print_esc("setbox");
@.Improper \\setbox@>
    help2("Sorry, \setbox is not allowed after \halign in a display,")@/
    ("or between \accent and an accented character."); error;
    end;
  end;

@ The |space_factor| or |prev_depth| settings are changed when a |set_aux|
command is sensed. Similarly, |prev_graf| is changed in the presence of
|set_prev_graf|, and |dead_cycles| or |insert_penalties| in the presence of
|set_page_int|. These definitions are always global.

When some dimension of a box register is changed, the change isn't exactly
global; but \TeX\ does not look at the \.{\\global} switch.

@<Assignments@>=
set_aux:alter_aux;
set_prev_graf:alter_prev_graf;
set_page_dimen:alter_page_so_far;
set_page_int:alter_integer;
set_box_dimen:alter_box_dimen;

@ @<Declare subprocedures for |prefixed_command|@>=
procedure alter_aux;
var c:halfword; {|hmode| or |vmode|}
begin if cur_chr<>abs(mode) then report_illegal_case
else  begin c:=cur_chr; scan_optional_equals;
  if c=vmode then
    begin scan_normal_dimen; prev_depth:=cur_val;
    end
  else  begin scan_int;
    if (cur_val<=0)or(cur_val>32767) then
      begin print_err("Bad space factor");
@.Bad space factor@>
      help1("I allow only values in the range 1..32767 here.");
      int_error(cur_val);
      end
    else space_factor:=cur_val;
    end;
  end;
end;

@ @<Declare subprocedures for |prefixed_command|@>=
procedure alter_prev_graf;
var p:0..nest_size; {index into |nest|}
begin nest[nest_ptr]:=cur_list; p:=nest_ptr;
while abs(nest[p].mode_field)<>vmode do decr(p);
scan_optional_equals; scan_int;
if cur_val<0 then
  begin print_err("Bad "); print_esc("prevgraf");
@.Bad \\prevgraf@>
  help1("I allow only nonnegative values here.");
  int_error(cur_val);
  end
else  begin nest[p].pg_field:=cur_val; cur_list:=nest[nest_ptr];
  end;
end;

@ @<Declare subprocedures for |prefixed_command|@>=
procedure alter_page_so_far;
var c:0..7; {index into |page_so_far|}
begin c:=cur_chr; scan_optional_equals; scan_normal_dimen;
page_so_far[c]:=cur_val;
end;

@ @<Declare subprocedures for |prefixed_command|@>=
procedure alter_integer;
var c:small_number;
  {0 for \.{\\deadcycles}, 1 for \.{\\insertpenalties}, etc.}
begin c:=cur_chr; scan_optional_equals; scan_int;
if c=0 then dead_cycles:=cur_val
@/@<Cases for |alter_integer|@>@/
else insert_penalties:=cur_val;
end;

@ @<Declare subprocedures for |prefixed_command|@>=
procedure alter_box_dimen;
var c:small_number; {|width_offset| or |height_offset| or |depth_offset|}
@!b:eight_bits; {box number}
begin c:=cur_chr; scan_register_num; b:=cur_val; scan_optional_equals;
scan_normal_dimen;
if box(b)<>null then vmem(box(b)+c).sc:=cur_val;
end;

@ Paragraph shapes are set up in an obvious way. It needs one word more than in
\TeX, though.

@<Assignments@>=
set_tex_shape: begin q:=cur_chr; scan_optional_equals; scan_int; n:=cur_val;
  if n<=0 then p:=null
  else begin p:=new_node(shape_node,2*(n+1)+1); vinfo(p+1):=n;
    for j:=1 to n do
      begin scan_normal_dimen;
      vmem(p+2*j).sc:=cur_val; {indentation}
      scan_normal_dimen;
      vmem(p+2*j+1).sc:=cur_val; {width}
      end;
    end;
  define(q,shape_ref,p);
  end;
set_etex_shape: begin q:=cur_chr; scan_optional_equals; scan_int; n:=cur_val;
  if n<=0 then p:=null
  else begin n:=(cur_val div 2)+1; p:=new_node(shape_node,2*n+1+1); vinfo(p+1):=n;
    n:=cur_val; vmem(p+2).int:=n; {number of penalties}
    for j:=p+3 to p+n+2 do
      begin scan_int; vmem(j).int:=cur_val; {penalty values}
      end;
    if not odd(n) then vmem(p+n+3).int:=0; {unused}
    end;
  define(q,shape_ref,p);
  end;

@ New language information data is loaded by the |hyph_data| command.

@<Put each...@>=
primitive_tex("hyphenation",hyph_data,0,0);
@!@:hyphenation_}{\.{\\hyphenation} primitive@>
primitive_tex("patterns",hyph_data,1,0);
@!@:patterns_}{\.{\\patterns} primitive@>
primitive_luatex("prehyphenchar",hyph_data,2,0);
@!@:prehyphenchar_}{\.{\\prehyphenchar} primitive@>
primitive_luatex("posthyphenchar",hyph_data,3,0);
@!@:posthyphenchar_}{\.{\\posthyphenchar} primitive@>
primitive_luatex("preexhyphenchar",hyph_data,4,0);
@!@:preexhyphenchar_}{\.{\\preexhyphenchar} primitive@>
primitive_luatex("postexhyphenchar",hyph_data,5,0);
@!@:postexhyphenchar_}{\.{\\postexhyphenchar} primitive@>

@ @<Assignments@>=
hyph_data: begin
   case cur_chr of
    0: new_hyph_exceptions;
    1: new_patterns;
    2: new_pre_hyphen_char;
    3: new_post_hyphen_char;
    4: new_pre_exhyphen_char;
    5: new_post_exhyphen_char;
    endcases;
  goto done;
  end;

@ All of \TeX's parameters are kept in |eqtb| except the font information,
the interaction mode, and the hyphenation tables; these are strictly global.

@<Assignments@>=
assign_font_dimen: set_font_dimen;
assign_font_int: begin
  n:=cur_chr; scan_font_ident; f:=cur_val;
  if n = no_lig_code then set_no_ligatures(f)
  else if n < lp_code_base then begin
    scan_optional_equals; scan_int;
    if n=0 then set_hyphen_char(f,cur_val)@+else set_skew_char(f,cur_val);
  end
  else begin
    scan_char_num; p := cur_val;
    scan_optional_equals; scan_int;
    case n of
    lp_code_base: set_lp_code(f, p, cur_val);
    rp_code_base: set_rp_code(f, p, cur_val);
    ef_code_base: set_ef_code(f, p, cur_val);
    tag_code:     set_tag_code(f, p, cur_val);
    end;
  end;
end;

@ @<Put each...@>=
primitive_tex("hyphenchar",assign_font_int,0,0);
@!@:hyphen_char_}{\.{\\hyphenchar} primitive@>
primitive_tex("skewchar",assign_font_int,1,0);
@!@:skew_char_}{\.{\\skewchar} primitive@>
primitive_pdftex("lpcode",assign_font_int,lp_code_base,0);
@!@:lp_code_}{\.{\\lpcode} primitive@>
primitive_pdftex("rpcode",assign_font_int,rp_code_base,0);
@!@:rp_code_}{\.{\\rpcode} primitive@>
primitive_pdftex("efcode",assign_font_int,ef_code_base,0);
@!@:ef_code_}{\.{\\efcode} primitive@>
primitive_pdftex("tagcode",assign_font_int,tag_code,0);
@!@:tag_code_}{\.{\\tagcode} primitive@>
primitive_pdftex("pdfnoligatures",assign_font_int,no_lig_code,0);
@!@:no_lig_code_}{\.{\\pdfnoligatures} primitive@>

@ Here is where the information for a new font gets loaded.

@<Assignments@>=
def_font: tex_def_font(a); {in C}
letterspace_font: new_letterspaced_font(a);
pdf_copy_font: make_font_copy(a);

@ @<Put each...@>=
primitive_tex("batchmode",set_interaction,batch_mode,0);
@!@:batch_mode_}{\.{\\batchmode} primitive@>
primitive_tex("nonstopmode",set_interaction,nonstop_mode,0);
@!@:nonstop_mode_}{\.{\\nonstopmode} primitive@>
primitive_tex("scrollmode",set_interaction,scroll_mode,0);
@!@:scroll_mode_}{\.{\\scrollmode} primitive@>
primitive_tex("errorstopmode",set_interaction,error_stop_mode,0);
@!@:error_stop_mode_}{\.{\\errorstopmode} primitive@>

@ @<Assignments@>=
set_interaction: new_interaction;

@ @<Declare subprocedures for |prefixed_command|@>=
procedure new_interaction;
begin print_ln;
interaction:=cur_chr;
@<Initialize the print |selector| based on |interaction|@>;
if log_opened then selector:=selector+2;
end;

@ The \.{\\afterassignment} command puts a token into the global
variable |after_token|. This global variable is examined just after
every assignment has been performed.

@<Glob...@>=
@!after_token:halfword; {zero, or a saved token}

@ @<Set init...@>=
after_token:=0;

@ @<Cases of |main_control| that don't...@>=
any_mode(after_assignment):begin get_token; after_token:=cur_tok;
  end;

@ @<Insert a token saved by \.{\\afterassignment}, if any@>=
if after_token<>0 then
  begin cur_tok:=after_token; back_input; after_token:=0;
  end

@ Here is a procedure that might be called `Get the next non-blank non-relax
non-call non-assignment token'.

@<Declare act...@>=
procedure do_assignments;
label exit;
begin loop begin @<Get the next non-blank non-relax...@>;
  if cur_cmd<=max_non_prefixed_command then return;
  set_box_allowed:=false; prefixed_command; set_box_allowed:=true;
  end;
exit:end;

@ @<Cases of |main_control| that don't...@>=
any_mode(after_group):begin get_token; save_for_after(cur_tok);
  end;

@ Files for \.{\\read} are opened and closed by the |in_stream| command.

@<Put each...@>=
primitive_tex("openin",in_stream,1,0);
@!@:open_in_}{\.{\\openin} primitive@>
primitive_tex("closein",in_stream,0,0);
@!@:close_in_}{\.{\\closein} primitive@>

@ @<Cases of |main_control| that don't...@>=
any_mode(in_stream): open_or_close_in;

@ @<Declare act...@>=
procedure open_or_close_in;
var c:0..1; {1 for \.{\\openin}, 0 for \.{\\closein}}
@!n:0..15; {stream number}
begin c:=cur_chr; scan_four_bit_int; n:=cur_val;
if read_open[n]<>closed then
  begin lua_a_close_in(read_file[n],(n+1)); read_open[n]:=closed;
  end;
if c<>0 then
  begin scan_optional_equals; scan_file_name;
  if cur_ext="" then cur_ext:=".tex";
  pack_cur_name;
  if lua_a_open_in(read_file[n],(n+1)) then begin
     read_file[n]:= name_file_pointer;
     read_open[n]:=just_open;
     end;
  end;
end;

@ The user can issue messages to the terminal, regardless of the
current mode.

@<Cases of |main_control| that don't...@>=
any_mode(message):issue_message;

@ @<Put each...@>=
primitive_tex("message",message,0,0);
@!@:message_}{\.{\\message} primitive@>
primitive_tex("errmessage",message,1,0);
@!@:err_message_}{\.{\\errmessage} primitive@>

@ @<Declare act...@>=
procedure issue_message;
var old_setting:0..max_selector; {holds |selector| setting}
junk:pointer;
@!c:0..1; {identifies \.{\\message} and \.{\\errmessage}}
@!s:str_number; {the message}
begin c:=cur_chr; junk:=scan_toks(false,true);
old_setting:=selector; selector:=new_string;
token_show(def_ref); selector:=old_setting;
flush_list(def_ref);
str_room(1); s:=make_string;
if c=0 then @<Print string |s| on the terminal@>
else @<Print string |s| as an error message@>;
flush_string;
end;

@ @<Print string |s| on the terminal@>=
begin if term_offset+length(s)>max_print_line-2 then print_ln
else if (term_offset>0)or(file_offset>0) then print_char(" ");
slow_print(s); update_terminal;
end

@ If \.{\\errmessage} occurs often in |scroll_mode|, without user-defined
\.{\\errhelp}, we don't want to give a long help message each time. So we
give a verbose explanation only once.

@<Glob...@>=
@!long_help_seen:boolean; {has the long \.{\\errmessage} help been used?}

@ @<Set init...@>=long_help_seen:=false;

@ @<Print string |s| as an error message@>=
begin print_err(""); slow_print(s);
if err_help<>null then use_err_help:=true
else if long_help_seen then help1("(That was another \errmessage.)")
else  begin if interaction<error_stop_mode then long_help_seen:=true;
  help4("This error message was generated by an \errmessage")@/
  ("command, so I can't give any explicit help.")@/
  ("Pretend that you're Hercule Poirot: Examine all clues,")@/
@^Poirot, Hercule@>
  ("and deduce the truth by order and method.");
  end;
error; use_err_help:=false;
end

@ The |error| routine calls on |give_err_help| if help is requested from
the |err_help| parameter.

@p procedure give_err_help;
begin token_show(err_help);
end;

@ The \.{\\uppercase} and \.{\\lowercase} commands are implemented by
building a token list and then changing the cases of the letters in it.

@<Cases of |main_control| that don't...@>=
any_mode(case_shift):shift_case;

@ @<Put each...@>=
primitive_tex("lowercase",case_shift,lc_code_base,lc_code_base);
@!@:lowercase_}{\.{\\lowercase} primitive@>
primitive_tex("uppercase",case_shift,uc_code_base,lc_code_base);
@!@:uppercase_}{\.{\\uppercase} primitive@>

@ @<Declare act...@>=
procedure shift_case;
var b:pointer; {|lc_code_base| or |uc_code_base|}
@!p:pointer; {runs through the token list}
@!t:halfword; {token}
@!c:halfword; {character code}
@!i:halfword; {inbetween}
begin b:=cur_chr; p:=scan_toks(false,false); p:=link(def_ref);
while p<>null do
  begin @<Change the case of the token in |p|, if a change is appropriate@>;
  p:=link(p);
  end;
back_list(link(def_ref)); free_avail(def_ref); {omit reference count}
end;

@ When the case of a |chr_code| changes, we don't change the |cmd|.
We also change active characters.

@<Change the case of the token in |p|, if a change is appropriate@>=
t:=info(p);
if t<cs_token_flag then begin
  c:=t mod string_offset;
  if b=uc_code_base then
    i:=get_uc_code(c)
  else
    i:=get_lc_code(c);
  if i<>0 then info(p):=t-c+i;
  end
else if is_active_csname(t-cs_token_flag) then begin
  c:=active_csname_value(t-cs_token_flag);
  if b=uc_code_base then
     i:=get_uc_code(c)
  else
     i:= get_lc_code(c);
  if i<>0 then info(p):=active_to_cs(i,true)+cs_token_flag;
end

@ We come finally to the last pieces missing from |main_control|, namely the
`\.{\\show}' commands that are useful when debugging.

@<Cases of |main_control| that don't...@>=
any_mode(xray): show_whatever;

@ @d show_code=0 { \.{\\show} }
@d show_box_code=1 { \.{\\showbox} }
@d show_the_code=2 { \.{\\showthe} }
@d show_lists=3 { \.{\\showlists} }

@<Put each...@>=
primitive_tex("show",xray,show_code,0);
@!@:show_}{\.{\\show} primitive@>
primitive_tex("showbox",xray,show_box_code,0);
@!@:show_box_}{\.{\\showbox} primitive@>
primitive_tex("showthe",xray,show_the_code,0);
@!@:show_the_}{\.{\\showthe} primitive@>
primitive_tex("showlists",xray,show_lists,0);
@!@:show_lists_}{\.{\\showlists} primitive@>

@ @<Declare act...@>=
procedure show_whatever;
label common_ending;
var p:pointer; {tail of a token list to show}
@!t:small_number; {type of conditional being shown}
@!m:normal..or_code; {upper bound on |fi_or_else| codes}
@!l:integer; {line where that conditional began}
@!n:integer; {level of \.{\\if...\\fi} nesting}
begin case cur_chr of
show_lists: begin begin_diagnostic; show_activities;
  end;
show_box_code: @<Show the current contents of a box@>;
show_code: @<Show the current meaning of a token, then |goto common_ending|@>;
@<Cases for |show_whatever|@>@;@/
othercases @<Show the current value of some parameter or register,
  then |goto common_ending|@>
endcases;@/
@<Complete a potentially long \.{\\show} command@>;
common_ending: if interaction<error_stop_mode then
  begin help0; decr(error_count);
  end
else if tracing_online>0 then
  begin@t@>@;@/
  help3("This isn't an error message; I'm just \showing something.")@/
  ("Type `I\show...' to show more (e.g., \show\cs,")@/
  ("\showthe\count10, \showbox255, \showlists).");
  end
else  begin@t@>@;@/
  help5("This isn't an error message; I'm just \showing something.")@/
  ("Type `I\show...' to show more (e.g., \show\cs,")@/
  ("\showthe\count10, \showbox255, \showlists).")@/
  ("And type `I\tracingonline=1\show...' to show boxes and")@/
  ("lists on your terminal as well as in the transcript file.");
  end;
error;
end;

@ @<Show the current meaning of a token...@>=
begin get_token;
if interaction=error_stop_mode then wake_up_terminal;
print_nl("> ");
if cur_cs<>0 then
  begin sprint_cs(cur_cs); print_char("=");
  end;
print_meaning; goto common_ending;
end

@ @<Show the current contents of a box@>=
begin scan_register_num; begin_diagnostic;
print_nl("> \box"); print_int(cur_val); print_char("=");
if box(cur_val)=null then print("void")
else show_box(box(cur_val));
end

@ @<Show the current value of some parameter...@>=
begin p:=the_toks;
if interaction=error_stop_mode then wake_up_terminal;
print_nl("> "); token_show(temp_token_head);
flush_list(link(temp_token_head)); goto common_ending;
end

@ @<Complete a potentially long \.{\\show} command@>=
end_diagnostic(true); print_err("OK");
@.OK@>
if selector=term_and_log then if tracing_online<=0 then
  begin selector:=term_only; print(" (see the transcript file)");
  selector:=term_and_log;
  end

@* \[50] Dumping and undumping the tables.
After \.{INITEX} has seen a collection of fonts and macros, it
can write all the necessary information on an auxiliary file so
that production versions of \TeX\ are able to initialize their
memory at high speed. The present section of the program takes
care of such output and input. We shall consider simultaneously
the processes of storing and restoring,
so that the inverse relation between them is clear.
@.INITEX@>

The global variable |format_ident| is a string that is printed right
after the |banner| line when \TeX\ is ready to start. For \.{INITEX} this
string says simply `\.{(INITEX)}'; for other versions of \TeX\ it says,
for example, `\.{(preloaded format=plain 1982.11.19)}', showing the year,
month, and day that the format file was created. We have |format_ident=0|
before \TeX's tables are loaded.

@<Glob...@>=
@!format_ident:str_number;
@!format_name:str_number; {principal file name}

@ @<Set init...@>=
format_ident:=0;
format_name:="";

@ @<Initialize table entries...@>=
format_ident:=" (INITEX)";

@ @<Declare act...@>=
@!init procedure store_fmt_file;
label found1,found2,done1,done2;
var j,@!k,@!l:integer; {all-purpose indices}
@!p: pointer; {all-purpose pointer}
@!x: integer; {something to dump}
@!w: four_quarters; {four ASCII codes}
begin @<If dumping is not allowed, abort@>;
@<Create the |format_ident|, open the format file,
  and inform the user that dumping has begun@>;
@<Dump constants for consistency check@>;
@<Dump the string pool@>;
@<Dump the dynamic memory@>;
@<Dump the table of equivalents@>;
@<Dump the font information@>;
@<Dump the active ocp information@>;
@<Dump the ocp information@>;
@<Dump the ocp list information@>;
@<Dump the hyphenation tables@>;
@<Dump pdftex data@>;
@<Dump a couple more things and the closing check word@>;
@<Dump the lua bytecodes@>;
@<Close the format file@>;
end;
tini

@ Corresponding to the procedure that dumps a format file, we have a function
that reads one in. The function returns |false| if the dumped format is
incompatible with the present \TeX\ table sizes, etc.

@d bad_fmt=6666 {go here if the format file is unacceptable}
@d too_small(#)==begin wake_up_terminal;
  wterm_ln('---! Must increase the ',#);
@.Must increase the x@>
  goto bad_fmt;
  end

@p @t\4@>@<Declare the function called |open_fmt_file|@>@;
function load_fmt_file:boolean;
label bad_fmt,exit;
var j,@!k:integer; {all-purpose indices}
@!p: pointer; {all-purpose pointer}
@!x: integer; {something undumped}
@!w: four_quarters; {four ASCII codes}
begin @<Undump constants for consistency check@>;
@<Undump the string pool@>;
@<Undump the dynamic memory@>;
@<Undump the table of equivalents@>;
@<Undump the font information@>;
@<Undump the active ocp information@>;
@<Undump the ocp information@>;
@<Undump the ocp list information@>;
@<Undump the hyphenation tables@>;
@<Undump pdftex data@>;
@<Undump a couple more things and the closing check word@>;
@<Undump the lua bytecodes@>;
prev_depth := pdf_ignored_dimen;
load_fmt_file:=true; return; {it worked!}
bad_fmt: wake_up_terminal;
  wterm_ln('(Fatal format file error; I''m stymied)');
@.Fatal format file error@>
load_fmt_file:=false;
exit:end;

@ The user is not allowed to dump a format file unless |save_ptr=0|.
This condition implies that |cur_level=level_one|, hence
the |xeq_level| array is constant and it need not be dumped.

@<If dumping is not allowed, abort@>=
if save_ptr<>0 then
  begin print_err("You can't dump inside a group");
@.You can't dump...@>
  help1("`{...\dump}' is a no-no."); succumb;
  end

@ Format files consist of |memory_word| items, and we use the following
macros to dump words of different types:

@d dump_wd(#)==begin fmt_file^:=#; put(fmt_file);@+end
@d dump_int(#)==begin fmt_file^.int:=#; put(fmt_file);@+end
@d dump_hh(#)==begin fmt_file^.hh:=#; put(fmt_file);@+end
@d dump_qqqq(#)==begin fmt_file^.qqqq:=#; put(fmt_file);@+end

@<Glob...@>=
@!fmt_file:word_file; {for input or output of format information}

@ The inverse macros are slightly more complicated, since we need to check
the range of the values we are reading in. We say `|undump(a)(b)(x)|' to
read an integer value |x| that is supposed to be in the range |a<=x<=b|.

@d undump_wd(#)==begin get(fmt_file); #:=fmt_file^;@+end
@d undump_int(#)==begin get(fmt_file); #:=fmt_file^.int;@+end
@d undump_hh(#)==begin get(fmt_file); #:=fmt_file^.hh;@+end
@d undump_qqqq(#)==begin get(fmt_file); #:=fmt_file^.qqqq;@+end
@d undump_end_end(#)==#:=x;@+end
@d undump_end(#)==(x>#) then goto bad_fmt@+else undump_end_end
@d undump(#)==begin undump_int(x); if (x<#) or undump_end
@d undump_size_end_end(#)==too_small(#)@+else undump_end_end
@d undump_size_end(#)==if x># then undump_size_end_end
@d undump_size(#)==begin undump_int(x);
  if x<# then goto bad_fmt; undump_size_end

@ The next few sections of the program should make it clear how we use the
dump/undump macros.

@<Dump constants for consistency check@>=
dump_int(@$);@/
dump_int(eqtb_size);@/
dump_int(hash_prime)

@ Sections of a \.{WEB} program that are ``commented out'' still contribute
strings to the string pool; therefore \.{INITEX} and \TeX\ will have
the same strings. (And it is, of course, a good thing that they do.)
@.WEB@>
@^string pool@>

@<Undump constants for consistency check@>=
x:=fmt_file^.int;
if x<>@$ then goto bad_fmt; {check that strings are the same}
undump_int(x);@/
if x<>eqtb_size then goto bad_fmt;
undump_int(x);
if x<>hash_prime then goto bad_fmt

@ @d dump_four_ASCII==
  w.b0:=qi(so(str_pool[k])); w.b1:=qi(so(str_pool[k+1]));
  w.b2:=qi(so(str_pool[k+2])); w.b3:=qi(so(str_pool[k+3]));
  dump_qqqq(w)

@<Dump the string pool@>=
dump_int(pool_ptr);
dump_int(str_ptr);
for k:=string_offset to str_ptr do dump_int(str_start_macro(k));
k:=0;
while k+4<pool_ptr do
  begin dump_four_ASCII; k:=k+4;
  end;
k:=pool_ptr-4; dump_four_ASCII;
print_ln; print_int(str_ptr-string_offset); print(" strings of total length ");
print_int(pool_ptr)

@ @d undump_four_ASCII==
  undump_qqqq(w);
  str_pool[k]:=si(qo(w.b0)); str_pool[k+1]:=si(qo(w.b1));
  str_pool[k+2]:=si(qo(w.b2)); str_pool[k+3]:=si(qo(w.b3))

@<Undump the string pool@>=
undump_size(0)(pool_size)('string pool size')(pool_ptr);
undump_size(0)(max_strings)('max strings')(str_ptr);
for k:=string_offset to str_ptr do undump(0)(pool_ptr)(str_start_macro(k));
k:=0;
while k+4<pool_ptr do
  begin undump_four_ASCII; k:=k+4;
  end;
k:=pool_ptr-4; undump_four_ASCII;
init_str_ptr:=str_ptr; init_pool_ptr:=pool_ptr

@ By sorting the list of available spaces in the variable-size portion of
|mem|, we are usually able to get by without having to dump very much
of the dynamic memory.

We recompute |var_used| and |dyn_used|, so that \.{INITEX} dumps valid
information even when it has not been gathering statistics.

@<Dump the dynamic memory@>=
dump_node_mem;
@#
dump_int(temp_token_head); dump_int(hold_token_head);
dump_int(omit_template); dump_int(null_list);
dump_int(backup_head); dump_int(garbage);
dump_int(fix_mem_min); dump_int(fix_mem_max);
dump_int(fix_mem_end);
dump_int(avail);
dyn_used:=fix_mem_end+1;
for k:=fix_mem_min to fix_mem_end do dump_wd(mem(k));
x:=x+(fix_mem_end+1-fix_mem_min);
p:=avail;
while p<>null do
  begin decr(dyn_used); p:=link(p);
  end;
dump_int(dyn_used);
print_ln; print_int(x);
print(" memory locations dumped; current usage is ");
print_int(var_used); print_char("&"); print_int(dyn_used)

@ @<Undump the dynamic memory@>=
undump_node_mem;
@#
undump_int(temp_token_head); undump_int(hold_token_head);
undump_int(omit_template); undump_int(null_list);
undump_int(backup_head); undump_int(garbage);
undump_int(fix_mem_min);undump_int(fix_mem_max);
fixmem:= xmallocarray (smemory_word, fix_mem_max+1);
memset (voidcast(fixmem),0,(fix_mem_max+1)*sizeof(smemory_word));
undump_int(fix_mem_end);
undump_int(avail);
for k:=fix_mem_min to fix_mem_end do undump_wd(mem(k));
undump_int(dyn_used)

@ @<Dump the table of equivalents@>=
@<Dump regions 1 to 4 of |eqtb|@>;
@<Dump regions 5 and 6 of |eqtb|@>;
dump_int(par_loc); dump_int(write_loc);@/
dump_math_codes;
dump_text_codes;
@<Dump the hash table@>

@ @<Undump the table of equivalents@>=
@<Undump regions 1 to 6 of |eqtb|@>;
undump(hash_base)(frozen_control_sequence)(par_loc);
par_token:=cs_token_flag+par_loc;@/
undump(hash_base)(frozen_control_sequence)(write_loc);@/
undump_math_codes;
undump_text_codes;
@<Undump the hash table@>

@ The table of equivalents usually contains repeated information, so we dump it
in compressed form: The sequence of $n+2$ values $(n,x_1,\ldots,x_n,m)$ in the
format file represents $n+m$ consecutive entries of |eqtb|, with |m| extra
copies of $x_n$, namely $(x_1,\ldots,x_n,x_n,\ldots,x_n)$.

@<Dump regions 1 to 4 of |eqtb|@>=
k:=null_cs;
repeat j:=k;
while j<int_base-1 do
  begin if (equiv(j)=equiv(j+1))and(eq_type(j)=eq_type(j+1))and@|
    (eq_level(j)=eq_level(j+1)) then goto found1;
  incr(j);
  end;
l:=int_base; goto done1; {|j=int_base-1|}
found1: incr(j); l:=j;
while j<int_base-1 do
  begin if (equiv(j)<>equiv(j+1))or(eq_type(j)<>eq_type(j+1))or@|
    (eq_level(j)<>eq_level(j+1)) then goto done1;
  incr(j);
  end;
done1:
dump_int(l-k);
while k<l do
  begin dump_wd(eqtb[k]); incr(k);
  end;
k:=j+1; dump_int(k-l);
until k=int_base

@ @<Dump regions 5 and 6 of |eqtb|@>=
repeat j:=k;
while j<eqtb_size do
  begin if eqtb[j].int=eqtb[j+1].int then goto found2;
  incr(j);
  end;
l:=eqtb_size+1; goto done2; {|j=eqtb_size|}
found2: incr(j); l:=j;
while j<eqtb_size do
  begin if eqtb[j].int<>eqtb[j+1].int then goto done2;
  incr(j);
  end;
done2:dump_int(l-k);
while k<l do
  begin dump_wd(eqtb[k]); incr(k);
  end;
k:=j+1; dump_int(k-l);
until k>eqtb_size

@ @<Undump regions 1 to 6 of |eqtb|@>=
k:=null_cs;
repeat undump_int(x);
if (x<1)or(k+x>eqtb_size+1) then goto bad_fmt;
for j:=k to k+x-1 do undump_wd(eqtb[j]);
k:=k+x;
undump_int(x);
if (x<0)or(k+x>eqtb_size+1) then goto bad_fmt;
for j:=k to k+x-1 do eqtb[j]:=eqtb[k-1];
k:=k+x;
until k>eqtb_size

@ A different scheme is used to compress the hash table, since its lower
region is usually sparse. When |text(p)<>0| for |p<=hash_used|, we output
two words, |p| and |hash[p]|. The hash table is, of course, densely packed
for |p>=hash_used|, so the remaining entries are output in a~block.

@<Dump the hash table@>=
dump_primitives;
dump_int(hash_used); cs_count:=frozen_control_sequence-1-hash_used;
for p:=hash_base to hash_used do if text(p)<>0 then
  begin dump_int(p); dump_hh(hash[p]); incr(cs_count);
  end;
for p:=hash_used+1 to undefined_control_sequence-1 do dump_hh(hash[p]);
dump_int(cs_count);@/
print_ln; print_int(cs_count); print(" multiletter control sequences")

@ @<Undump the hash table@>=
undump_primitives;
undump(hash_base)(frozen_control_sequence)(hash_used); p:=hash_base-1;
repeat undump(p+1)(hash_used)(p); undump_hh(hash[p]);
until p=hash_used;
for p:=hash_used+1 to undefined_control_sequence-1 do undump_hh(hash[p]);
undump_int(cs_count)

@ @<Dump the font information@>=
dump_int(max_font_id);
for k:=0 to max_font_id do
  @<Dump the array info for internal font number |k|@>;
print_ln; print_int(max_font_id); print(" preloaded font");
if max_font_id<>1 then print_char("s");
dump_math_data

@ @<Undump the font information@>=
undump_int(x);
set_max_font_id(x);
for k:=0 to max_font_id do
  @<Undump the array info for internal font number |k|@>;
undump_math_data

@ @<Dump the array info for internal font number |k|@>=
begin dump_font(k);
print_nl("\font"); print_esc(font_id_text(k)); print_char("=");
print_file_name(tex_font_name(k),tex_font_area(k),"");
flush_string; flush_string;
if font_size(k)<>font_dsize(k) then
  begin print(" at "); print_scaled(font_size(k)); print("pt");
  end;
end

@ @<Undump the array info for internal font number |k|@>=
begin undump_font(k);@/
end

@ @<Dump the active ocp information@>=
dump_int(active_min_ptr);
dump_int(active_max_ptr);
for k:=0 to active_max_ptr-1 do dump_wd(active_info[k]);
if active_max_ptr>0 then begin
  print_ln; print_int(active_max_ptr); print(" words of active ocps");
  end;

@ @<Undump the active ocp information@>=
undump_size(0)(active_mem_size)('active start point')(active_min_ptr);
undump_size(0)(active_mem_size)('active mem size')(active_max_ptr);
for k:=0 to active_max_ptr-1 do undump_wd(active_info[k]);

@ @<Dump the ocp information@>=
dump_int(ocp_ptr);
for k:=null_ocp to ocp_ptr do
  @<Dump the array info for internal ocp number |k|@>;
if ocp_ptr-ocp_base>0 then begin
  print_ln; print_int(ocp_ptr-ocp_base); print(" preloaded ocp");
  if ocp_ptr<>ocp_base+1 then print_char("s");
  end

@ @<Undump the ocp information@>=
undump_size(ocp_base)(ocp_biggest)('ocp max')(ocp_ptr);
for k:=null_ocp to ocp_ptr do
  @<Undump the array info for internal ocp number |k|@>

@ @<Dump the array info for internal ocp number |k|@>=
begin dump_ocp_table(k);
if ocp_ptr-ocp_base>0 then begin
  print_nl("\ocp"); print_esc(ocp_id_text(k)); print_char("=");
  print_file_name(ocp_name(k),ocp_area(k),"");
  end;
end

@ @<Undump the array info for internal ocp number |k|@>=
begin undump_ocp_table(k);
end

@ @<Dump the ocp list information@>=
dump_int(ocp_listmem_ptr);
for k:=0 to ocp_listmem_ptr-1 do dump_wd(ocp_list_info[k]);
dump_int(ocp_list_ptr);
for k:=null_ocp_list to ocp_list_ptr do begin
  dump_int(ocp_list_list[k]);
  if null_ocp_list<>ocp_list_ptr then begin
    print_nl("\ocplist");
    print_esc(ocp_list_id_text(k));
    print_char("=");
    print_ocp_list(ocp_list_list[k]);
    end;
  end;
dump_int(ocp_lstackmem_ptr);
for k:=0 to ocp_lstackmem_ptr-1 do dump_wd(ocp_lstack_info[k])

@ @<Undump the ocp list information@>=
undump_size(1)(1000000)('ocp list mem size')(ocp_listmem_ptr);
for k:=0 to ocp_listmem_ptr-1 do undump_wd(ocp_list_info[k]);
undump_size(ocp_list_base)(ocp_list_biggest)('ocp list max')(ocp_list_ptr);
for k:=null_ocp_list to ocp_list_ptr do
  undump_int(ocp_list_list[k]);
undump_size(1)(1000000)('ocp lstack mem size')(ocp_lstackmem_ptr);
for k:=0 to ocp_lstackmem_ptr-1 do undump_wd(ocp_lstack_info[k])

@ This is done in C

@<Dump the hyphenation tables@>=
dump_language_data

@ @<Undump the hyphenation tables@>=
undump_language_data

@ Store some of the pdftex data structures in the format. The idea here is
to ensure that any data structures referenced from pdftex-specific whatsit
nodes are retained. For the sake of simplicity and speed, all the filled parts
of |pdf_mem| and |obj_tab| are retained, in the present implementation. We also
retain three of the linked lists that start from |head_tab|, so that it is
possible to, say, load an image in the \.{INITEX} run and then reference it in a
\.{VIRTEX} run that uses the dumped format.

@<Dump pdftex data@>=
begin
dumpimagemeta; {the image information array }
dump_int(pdf_mem_size);
dump_int(pdf_mem_ptr);
for k:=1 to pdf_mem_ptr-1 do begin
  dump_int(pdf_mem[k]);
  end;
print_ln; print_int(pdf_mem_ptr-1); print(" words of pdf memory");
dump_int(obj_tab_size);
dump_int(obj_ptr);
dump_int(sys_obj_ptr);
for k:=1 to sys_obj_ptr do begin
  dump_int(obj_tab[k].int0);
  dump_int(obj_tab[k].int1);
  dump_int(obj_tab[k].int3);
  dump_int(obj_tab[k].int4);
  end;
print_ln; print_int(sys_obj_ptr); print(" indirect objects");
dump_int(pdf_obj_count);
dump_int(pdf_xform_count);
dump_int(pdf_ximage_count);
dump_int(head_tab[obj_type_obj]);
dump_int(head_tab[obj_type_xform]);
dump_int(head_tab[obj_type_ximage]);
dump_int(pdf_last_obj);
dump_int(pdf_last_xform);
dump_int(pdf_last_ximage);
end

@ And restoring the pdftex data structures from the format. The
two function arguments to |undumpimagemeta| have been restored
already in an earlier module.

@<Undump pdftex data@>=
begin
undumpimagemeta(pdf_minor_version,pdf_inclusion_errorlevel);  {the image information array }
undump_int(pdf_mem_size);
pdf_mem := xreallocarray(pdf_mem, integer, pdf_mem_size);
undump_int(pdf_mem_ptr);
for k:=1 to pdf_mem_ptr-1 do begin
  undump_int(pdf_mem[k]);
  end;
undump_int(obj_tab_size);
undump_int(obj_ptr);
undump_int(sys_obj_ptr);
for k:=1 to sys_obj_ptr do begin
  undump_int(obj_tab[k].int0);
  undump_int(obj_tab[k].int1);
  obj_tab[k].int2 := -1;
  undump_int(obj_tab[k].int3);
  undump_int(obj_tab[k].int4);
  end;
undump_int(pdf_obj_count);
undump_int(pdf_xform_count);
undump_int(pdf_ximage_count);
undump_int(head_tab[obj_type_obj]);
undump_int(head_tab[obj_type_xform]);
undump_int(head_tab[obj_type_ximage]);
undump_int(pdf_last_obj);
undump_int(pdf_last_xform);
undump_int(pdf_last_ximage);
end


@ This is also done in C

@<Dump the lua bytecodes@>=
dump_luac_registers;

@ @<Undump the lua bytecodes@>=
undump_luac_registers;

@ We have already printed a lot of statistics, so we set |tracing_stats:=0|
to prevent them from appearing again.

@<Dump a couple more things and the closing check word@>=
dump_int(interaction); dump_int(format_ident); dump_int(format_name); dump_int(69069);
tracing_stats:=0

@ @<Undump a couple more things and the closing check word@>=
undump(batch_mode)(error_stop_mode)(interaction);
undump(0)(str_ptr)(format_ident);
undump(0)(str_ptr)(format_name);
undump_int(x);
if (x<>69069)or eof(fmt_file) then goto bad_fmt

@ @<Create the |format_ident|...@>=
selector:=new_string;
print(" (preloaded format="); print(job_name); print_char(" ");
print_int(year); print_char(".");
print_int(month); print_char("."); print_int(day); print_char(")");
str_room(2);
format_ident:=make_string;
print(job_name);
format_name:=make_string;
if interaction=batch_mode then selector:=log_only
else selector:=term_and_log;
pack_job_name(format_extension);
while not w_open_out(fmt_file) do
  prompt_file_name('format file name',format_extension);
print_nl("Beginning to dump on file ");
@.Beginning to dump...@>
slow_print(w_make_name_string(fmt_file)); flush_string;
print_nl(""); slow_print(format_ident)

@ @<Close the format file@>=
w_close(fmt_file)

@* \[51] The main program.
This is it: the part of \TeX\ that executes all those procedures we have
written.

Well---almost. Let's leave space for a few more routines that we may
have forgotten.

@p @<Last-minute procedures@>

@ We have noted that there are two versions of \TeX82. One, called \.{INITEX},
@.INITEX@>
has to be run first; it initializes everything from scratch, without
reading a format file, and it has the capability of dumping a format file.
The other one is called `\.{VIRTEX}'; it is a ``virgin'' program that needs
@.VIRTEX@>
to input a format file in order to get started. \.{VIRTEX} typically has
more memory capacity than \.{INITEX}, because it does not need the space
consumed by the auxiliary hyphenation tables and the numerous calls on
|primitive|, etc.

The \.{VIRTEX} program cannot read a format file instantaneously, of course;
the best implementations therefore allow for production versions of \TeX\ that
not only avoid the loading routine for \PASCAL\ object code, they also have
a format file pre-loaded. This is impossible to do if we stick to standard
\PASCAL; but there is a simple way to fool many systems into avoiding the
initialization, as follows:\quad(1)~We declare a global integer variable
called |ready_already|. The probability is negligible that this
variable holds any particular value like 314159 when \.{VIRTEX} is first
loaded.\quad(2)~After we have read in a format file and initialized
everything, we set |ready_already:=314159|.\quad(3)~Soon \.{VIRTEX}
will print `\.*', waiting for more input; and at this point we
interrupt the program and save its core image in some form that the
operating system can reload speedily.\quad(4)~When that core image is
activated, the program starts again at the beginning; but now
|ready_already=314159| and all the other global variables have
their initial values too. The former chastity has vanished!

In other words, if we allow ourselves to test the condition
|ready_already=314159|, before |ready_already| has been
assigned a value, we can avoid the lengthy initialization. Dirty tricks
rarely pay off so handsomely.
@^dirty \PASCAL@>
@^system dependencies@>

On systems that allow such preloading, the standard program called \.{TeX}
should be the one that has \.{plain} format preloaded, since that agrees
with {\sl The \TeX book}. Other versions, e.g., \.{AmSTeX}, should also
@:TeXbook}{\sl The \TeX book@>
@.AmSTeX@>
@.plain@>
be provided for commonly used formats.

@<Glob...@>=
@!ready_already:integer; {a sacrifice of purity for economy}

@ Now this is really it: \TeX\ starts and ends here.

The initial test involving |ready_already| should be deleted if the
\PASCAL\ runtime system is smart enough to detect such a ``mistake.''
@^system dependencies@>

@p begin @!{|start_here|}
history:=fatal_error_stop; {in case we quit during initialization}
t_open_out; {open the terminal for output}
if ready_already=314159 then goto start_of_TEX;
@<Check the ``constant'' values...@>@;
if bad>0 then
  begin wterm_ln('Ouch---my internal constants have been clobbered!',
    '---case ',bad:1);
@.Ouch...clobbered@>
  goto final_end;
  end;
initialize; {set global variables to their starting values}
@!init if not get_strings_started then goto final_end;
init_prim; {call |primitive| for each primitive}
init_str_ptr:=str_ptr; init_pool_ptr:=pool_ptr; fix_date_and_time;
tini@/
ready_already:=314159;
start_of_TEX: @<Initialize the output routines@>;
@<Get the first line of input and prepare to start@>;
history:=spotless; {ready to go!}
@<Initialize synctex primitive@>
main_control; {come to life}
final_cleanup; {prepare for death}
end_of_TEX: close_files_and_terminate;
final_end: ready_already:=0;
end.

@ Put this in a function because two extra variables are needed
for callback testing, and putting those inside the main body is
ugly

@<Basic print...@>=
procedure print_banner;
var res:boolean;
   callback_id:integer;
begin
callback_id:=callback_defined(start_run_callback);
if callback_id=0 then begin
  wterm(banner);
  if format_ident=0 then wterm_ln(' (no format preloaded)')
  else  begin slow_print(format_ident); print_ln;
    end;
  end
else if callback_id>0 then
  res:= run_callback(callback_id,'->');
update_terminal;
end;
@#
procedure print_version_banner;
begin
wterm(banner);
write_svnversion(luatex_svnversion);
end;


@ Here we do whatever is needed to complete \TeX's job gracefully on the
local operating system. The code here might come into play after a fatal
error; it must therefore consist entirely of ``safe'' operations that
cannot produce error messages. For example, it would be a mistake to call
|str_room| or |make_string| at this time, because a call on |overflow|
might lead to an infinite loop.
@^system dependencies@>

Actually there's one way to get error messages, via |prepare_mag|;
but that can't cause infinite recursion.
@^recursion@>

This program doesn't bother to close the input files that may still be open.

@<Last-minute...@>=
procedure close_files_and_terminate;
label done, done1;
var a, b, i, j, k, l: integer; {all-purpose index}
    is_names: boolean; {flag for name tree output: is it Names or Kids?}
    root, outlines, threads, names_tree, dests: integer;
    xref_offset_width, names_head, names_tail: integer;
        callback_id:integer;
        res:boolean;
begin
callback_id:=callback_defined(stop_run_callback);
@<Finish the extensions@>;
@!stat if tracing_stats>0 then
  if callback_id=0 then @<Output statistics about this job@>;@;@+tats@/
wake_up_terminal;
if not fixed_pdfoutput_set then {else there will be an infinite loop in error case}
    fix_pdfoutput;
if fixed_pdfoutput > 0 then begin
    if history = fatal_error_stop then begin
        remove_pdffile;
        print_err(" ==> Fatal error occurred, no output PDF file produced!")
    end
    else begin
        @<Finish the PDF file@>;
        if callback_id=0 then begin
            if log_opened then
                begin wlog_cr;
                wlog_ln('PDF statistics:');
                wlog_ln(' ',obj_ptr:1,' PDF objects out of ',obj_tab_size:1,
                    ' (max. ',sup_obj_tab_size:1,')');
                if pdf_os_cntr > 0 then begin
                    wlog(' ',((pdf_os_cntr - 1) * pdf_os_max_objs + pdf_os_objidx + 1):1,
                        ' compressed objects within ',pdf_os_cntr:1,' object stream');
                    if pdf_os_cntr > 1 then
                        wlog('s');
                    wlog_cr;
                end;
                wlog_ln(' ',pdf_dest_names_ptr:1,' named destinations out of ',dest_names_size:1,
                    ' (max. ',sup_dest_names_size:1,')');
                wlog_ln(' ',pdf_mem_ptr:1,' words of extra memory for PDF output out of ',pdf_mem_size:1,
                    ' (max. ',sup_pdf_mem_size:1,')');
            end;
        end;
    end;
end
else begin
    @<Finish the \.{DVI} file@>;
end;
@<Close {\sl Sync\TeX} file and write status@>;
free_text_codes;
free_math_codes;
if log_opened then
  begin wlog_cr; selector:=selector-2;
  if (selector=term_only)and(callback_id=0) then begin
     print_nl("Transcript written on ");
@.Transcript written...@>
     slow_print(log_name); print_char(".");
    end;
  lua_a_close_out(log_file);
  end;
end;

@ The present section goes directly to the log file instead of using
|print| commands, because there's no need for these strings to take
up |str_pool| memory when a non-{\bf stat} version of \TeX\ is being used.

@<Output statistics...@>=
if log_opened then
  begin wlog_ln(' ');
  wlog_ln('Here is how much of TeX''s memory',' you used:');
@.Here is how much...@>
  wlog(' ',str_ptr-init_str_ptr:1,' string');
  if str_ptr<>init_str_ptr+1 then wlog('s');
  wlog_ln(' out of ', max_strings-init_str_ptr+string_offset:1);@/
  wlog_ln(' ',pool_ptr-init_pool_ptr:1,' string characters out of ',
    pool_size-init_pool_ptr:1);@/
  wlog_ln(' ',var_mem_max:1,',',fix_mem_max:1,@|
    ' words of node,token memory allocated');@/
  print_node_mem_stats;
  wlog_ln(' ',cs_count:1,' multiletter control sequences out of ',
    hash_size:1);@/
  wlog(' ',max_font_id,' font');
  if max_font_id<>1 then wlog('s');
  wlog_ln(' using ', font_bytes:1, ' bytes');
  wlog_ln(' ',max_in_stack:1,'i,',max_nest_stack:1,'n,',@|
    max_param_stack:1,'p,',@|
    max_buf_stack+1:1,'b,',@|
    max_save_stack+6:1,'s stack positions out of ',@|
    stack_size:1,'i,',
    nest_size:1,'n,',
    param_size:1,'p,',
    buf_size:1,'b,',
    save_size:1,'s');
  end

@ We get to the |final_cleanup| routine when \.{\\end} or \.{\\dump} has
been scanned and |its_all_over|\kern-2pt.

@<Last-minute...@>=
procedure final_cleanup;
label exit;
var c:small_number; {0 for \.{\\end}, 1 for \.{\\dump}}
i:halfword; { for looping marks }
begin c:=cur_chr;
if job_name=0 then open_log_file;
while input_ptr>0 do
  if state=token_list then end_token_list@+else end_file_reading;
while open_parens>0 do
  begin
        if tracefilenames then print(" )");
        decr(open_parens);
  end;
if cur_level>level_one then
  begin print_nl("("); print_esc("end occurred ");
  print("inside a group at level ");
@:end_}{\.{(\\end occurred...)}@>
  print_int(cur_level-level_one); print_char(")");
  show_save_groups;
  end;
while cond_ptr<>null do
  begin print_nl("("); print_esc("end occurred ");
  print("when "); print_cmd_chr(if_test,cur_if);
  if if_line<>0 then
    begin print(" on line "); print_int(if_line);
    end;
  print(" was incomplete)");
  if_line:=if_line_field(cond_ptr);
  cur_if:=subtype(cond_ptr); temp_ptr:=cond_ptr;
  cond_ptr:=vlink(cond_ptr); flush_node(temp_ptr);
  end;
if callback_defined(stop_run_callback)=0 then
  if history<>spotless then
    if ((history=warning_issued)or(interaction<error_stop_mode)) then
      if selector=term_and_log then
        begin selector:=term_only;
        print_nl("(see the transcript file for additional information)");
@.see the transcript file...@>
        selector:=term_and_log;
        end;
if c=1 then
  begin @!init for i:=0 to biggest_used_mark do begin
    delete_top_mark(i); delete_first_mark(i); delete_bot_mark(i);
    delete_split_first_mark(i); delete_split_bot_mark(i);
    end;
  for c:=last_box_code to vsplit_code do flush_node_list(disc_ptr[c]);
  if last_glue<>max_halfword then delete_glue_ref(last_glue);
  @<Close the pseudo files@>;
  store_fmt_file; return;@+tini@/
  print_nl("(\dump is performed only by INITEX)"); return;
@:dump_}{\.{\\dump...only by INITEX}@>
  end;
exit:end;

@ @<Last-minute...@>=
@!init procedure init_prim; {initialize all the primitives}
begin no_new_control_sequence:=false;
first:=0;
@<Put each...@>;
no_new_control_sequence:=true;
end;
tini

@ When we begin the following code, \TeX's tables may still contain garbage;
the strings might not even be present. Thus we must proceed cautiously to get
bootstrapped in.

But when we finish this part of the program, \TeX\ is ready to call on the
|main_control| routine to do its work.

@<Get the first line...@>=
begin @<Initialize the input routines@>;
@<Enable \eTeX, if requested@>@;@/
if (format_ident=0)or(buffer[loc]="&") then
  begin if format_ident<>0 then initialize; {erase preloaded format}
  if not open_fmt_file then goto final_end;
  if not load_fmt_file then
    begin w_close(fmt_file); goto final_end;
    end;
  w_close(fmt_file);
  while (loc<limit)and(buffer[loc]=" ") do incr(loc);
  end;
if (pdf_output_option <> 0) then pdf_output := pdf_output_value;
if (pdf_draftmode_option <> 0) then pdf_draftmode := pdf_draftmode_value;
pdf_init_map_file('pdftex.map');
if false then wterm_ln('entering extended mode');
if end_line_char_inactive then decr(limit)
else  buffer[limit]:=end_line_char;
fix_date_and_time;@/
random_seed :=(microseconds*1000)+(epochseconds mod 1000000);@/
init_randoms(random_seed);@/
initialize_math;
@<Initialize the print |selector|...@>;
check_texconfig_init;
if (loc<limit)and(get_cat_code(cat_code_table,buffer[loc])<>escape) then start_input;
  {\.{\\input} assumed}
@<DIR: Initialize |text_dir_ptr|@>;
end

@* \[52] Debugging.
Once \TeX\ is working, you should be able to diagnose most errors with
the \.{\\show} commands and other diagnostic features. But for the initial
stages of debugging, and for the revelation of really deep mysteries, you
can compile \TeX\ with a few more aids, including the \PASCAL\ runtime
checks and its debugger. An additional routine called |debug_help|
will also come into play when you type `\.D' after an error message;
|debug_help| also occurs just before a fatal error causes \TeX\ to succumb.
@^debugging@>
@^system dependencies@>

The interface to |debug_help| is primitive, but it is good enough when used
with a \PASCAL\ debugger that allows you to set breakpoints and to read
variables and change their values. After getting the prompt `\.{debug \#}', you
type either a negative number (this exits |debug_help|), or zero (this
goes to a location where you can set a breakpoint, thereby entering into
dialog with the \PASCAL\ debugger), or a positive number |m| followed by
an argument |n|. The meaning of |m| and |n| will be clear from the
program below. (If |m=13|, there is an additional argument, |l|.)
@.debug \#@>

@d breakpoint=888 {place where a breakpoint is desirable}

@<Last-minute...@>=
@!debug procedure debug_help; {routine to display various things}
label breakpoint,exit;
var k,@!l,@!m,@!n:integer;
begin loop begin wake_up_terminal;
  print_nl("debug # (-1 to exit):"); update_terminal;
@.debug \#@>
  read(term_in,m);
  if m<0 then return
  else if m=0 then
    begin goto breakpoint;@\ {go to every label at least once}
    breakpoint: m:=0; @{'BREAKPOINT'@}@\
    end
  else  begin read(term_in,n);
    case m of
    @t\4@>@<Numbered cases for |debug_help|@>@;
    othercases print("?")
    endcases;
    end;
  end;
exit:end;
gubed

@ @<Numbered cases...@>=
1: print_word(mem(n)); {display |mem[n]| in all forms}
2: print_int(info(n));
3: print_int(link(n));
4: print_word(eqtb[n]);
5: ;
6: print_word(save_stack[n]);
7: show_box(n);
  {show a box, abbreviated by |show_box_depth| and |show_box_breadth|}
8: begin breadth_max:=10000; depth_threshold:=pool_size-pool_ptr-10;
  show_node_list(n); {show a box in its entirety}
  end;
9: show_token_list(n,null,1000);
10: slow_print(n);
13: begin read(term_in,l); print_cmd_chr(n,l);
  end;
14: for k:=0 to n do print(buffer[k]);
15: begin font_in_short_display:=null_font; short_display(n);
  end;

@* \[53] Extensions.
The program above includes a bunch of ``hooks'' that allow further
capabilities to be added without upsetting \TeX's basic structure.
Most of these hooks are concerned with ``whatsit'' nodes, which are
intended to be used for special purposes; whenever a new extension to
\TeX\ involves a new kind of whatsit node, a corresponding change needs
to be made to the routines below that deal with such nodes,
but it will usually be unnecessary to make many changes to the
other parts of this program.

In order to demonstrate how extensions can be made, we shall treat
`\.{\\write}', `\.{\\openout}', `\.{\\closeout}', `\.{\\immediate}',
and `\.{\\special}' as if they were extensions.
These commands are actually primitives of \TeX, and they should
appear in all implementations of the system; but let's try to imagine
that they aren't. Then the program below illustrates how a person
could add them.

Sometimes, of course, an extension will require changes to \TeX\ itself;
no system of hooks could be complete enough for all conceivable extensions.
The features associated with `\.{\\write}' are almost all confined to the
following paragraphs, but there are small parts of the |print_ln| and
|print_char| procedures that were introduced specifically to \.{\\write}
characters. Furthermore one of the token lists recognized by the scanner
is a |write_text|; and there are a few other miscellaneous places where we
have already provided for some aspect of \.{\\write}.  The goal of a \TeX\
extender should be to minimize alterations to the standard parts of the
program, and to avoid them completely if possible. He or she should also
be quite sure that there's no easy way to accomplish the desired goals
with the standard features that \TeX\ already has. ``Think thrice before
extending,'' because that may save a lot of work, and it will also keep
incompatible extensions of \TeX\ from proliferating.
@^system dependencies@>
@^extensions to \TeX@>

@ First let's consider the format of whatsit nodes that are used to represent
the data associated with \.{\\write} and its relatives. Recall that a whatsit
has |type=whatsit_node|, and the |subtype| is supposed to distinguish
different kinds of whatsits. Each node occupies two or more words; the
exact number is immaterial, as long as it is readily determined from the
|subtype| or other data.

We shall introduce five |subtype| values here, corresponding to the
control sequences \.{\\openout}, \.{\\write}, \.{\\closeout}, and \.{\\special}.
The second word of I/O whatsits has a |write_stream| field
that identifies the write-stream number (0 to 15, or 16 for out-of-range and
positive, or 17 for out-of-range and negative).
In the case of \.{\\write} and \.{\\special}, there is also a field that
points to the reference count of a token list that should be sent. In the
case of \.{\\openout}, we need three words and three auxiliary subfields
to hold the string numbers for name, area, and extension.

@d open_node=0 {|subtype| in whatsits that represent files to \.{\\openout}}
@d write_node=1 {|subtype| in whatsits that represent things to \.{\\write}}
@d close_node=2 {|subtype| in whatsits that represent streams to \.{\\closeout}}
@d special_node=3 {|subtype| in whatsits that represent \.{\\special} things}
@d dir_dir(#)==vinfo(#+2) {keep the direction to be taken}
@d dir_level(#)==vlink(#+2) {the save level at which the direction was defined}
@d dir_dvi_ptr(#)==vinfo(#+3) {for reflecting dvi output}
@d dir_dvi_h(#)==vlink(#+3) {for reflecting dvi output}
@d dir_box_pos_h(#)==vinfo(#+4) {for reflecting dvi output}
@d dir_box_pos_v(#)==vlink(#+4) {for reflecting dvi output}
@d dir_cur_h(#)==vinfo(#+5) {for reflecting dvi output}
@d dir_cur_v(#)==vlink(#+5) {for reflecting dvi output}
@d what_lang(#)==vlink(#+2) {language number, in the range |0..255|}
@d what_lhm(#)==type(#+2) {minimum left fragment, in the range |1..63|}
@d what_rhm(#)==subtype(#+2) {minimum right fragment, in the range |1..63|}
@d write_tokens(#) == vlink(#+2) {reference count of token list to write}
@d write_stream(#) == vinfo(#+2) {stream number (0 to 17)}
@d open_name(#) == vlink(#+2) {string number of file name to open}
@d open_area(#) == vinfo(#+3) {string number of file area for |open_name|}
@d open_ext(#) == vlink(#+3) {string number of file extension for |open_name|}

@ The sixteen possible \.{\\write} streams are represented by the |write_file|
array. The |j|th file is open if and only if |write_open[j]=true|. The last
two streams are special; |write_open[16]| represents a stream number
greater than 15, while |write_open[17]| represents a negative stream number,
and both of these variables are always |false|.

@<Glob...@>=
@!write_file:array[0..15] of alpha_file;
@!write_file_mode:array[0..15] of halfword;
@!write_file_translation:array[0..15] of halfword;
@!write_open:array[0..17] of boolean;
@!neg_wd:scaled;
@!pos_wd:scaled;
@!neg_ht:scaled;
@!dvi_direction:integer;
@!dir_primary:array[0..31] of 0..31;
@!dir_secondary:array[0..31] of 0..31;
@!dir_tertiary:array[0..31] of 0..31;
@!dir_rearrange:array[0..3] of 0..31;
@!dir_names:array[0..3] of str_number;
@!text_dir_ptr:pointer;
@!text_dir_tmp:pointer;

@
@<Set init...@>=
for k:=0 to 17 do write_open[k]:=false;
pack_direction:=-1;
for k:= 0 to 7 do begin
  dir_primary  [k   ]:=dir_T;
  dir_primary  [k+ 8]:=dir_L;
  dir_primary  [k+16]:=dir_B;
  dir_primary  [k+24]:=dir_R;
  end;
for k:= 0 to 3 do begin
  dir_secondary[k   ]:=dir_L;
  dir_secondary[k+ 4]:=dir_R;
  dir_secondary[k+ 8]:=dir_T;
  dir_secondary[k+12]:=dir_B;

  dir_secondary[k+16]:=dir_L;
  dir_secondary[k+20]:=dir_R;
  dir_secondary[k+24]:=dir_T;
  dir_secondary[k+28]:=dir_B;
  end;
for k:=0 to 7 do begin
  dir_tertiary[k*4  ]:=dir_T;
  dir_tertiary[k*4+1]:=dir_L;
  dir_tertiary[k*4+2]:=dir_B;
  dir_tertiary[k*4+3]:=dir_R;
  end;
dir_rearrange[0]:=0;
dir_rearrange[1]:=0;
dir_rearrange[2]:=1;
dir_rearrange[3]:=1;
dir_names[0]:="T";
dir_names[1]:="L";
dir_names[2]:="B";
dir_names[3]:="R";

@ Extensions might introduce new command codes; but it's best to use
|extension| with a modifier, whenever possible, so that |main_control|
stays the same.

@d immediate_code=4 {command modifier for \.{\\immediate}}
@d local_par_node==6 {|subtype| in whatsits for local paragraph node}
{|local_par_node| has to be a macro, not numeric }
@d dir_node=7 {|subtype| in whatsits for change direction node}
@d pdftex_first_extension_code = 8
@d pdf_literal_node            == pdftex_first_extension_code + 0
@d pdf_obj_code                == pdftex_first_extension_code + 1
@d pdf_refobj_node             == pdftex_first_extension_code + 2
@d pdf_xform_code              == pdftex_first_extension_code + 3
@d pdf_refxform_node           == pdftex_first_extension_code + 4
@d pdf_ximage_code             == pdftex_first_extension_code + 5
@d pdf_refximage_node          == pdftex_first_extension_code + 6
@d pdf_annot_node              == pdftex_first_extension_code + 7
@d pdf_start_link_node         == pdftex_first_extension_code + 8
@d pdf_end_link_node           == pdftex_first_extension_code + 9
@d pdf_outline_code            == pdftex_first_extension_code + 10
@d pdf_dest_node               == pdftex_first_extension_code + 11
@d pdf_thread_node             == pdftex_first_extension_code + 12
@d pdf_start_thread_node       == pdftex_first_extension_code + 13
@d pdf_end_thread_node         == pdftex_first_extension_code + 14
@d pdf_save_pos_node           == pdftex_first_extension_code + 15
@d pdf_info_code               == pdftex_first_extension_code + 16
@d pdf_thread_data_node        == pdftex_first_extension_code + 16
@d pdf_catalog_code            == pdftex_first_extension_code + 17
@d pdf_link_data_node          == pdftex_first_extension_code + 17
@d pdf_names_code              == pdftex_first_extension_code + 18
@d pdf_font_attr_code          == pdftex_first_extension_code + 19
@d pdf_include_chars_code      == pdftex_first_extension_code + 20
@d pdf_map_file_code           == pdftex_first_extension_code + 21
@d pdf_map_line_code           == pdftex_first_extension_code + 22
@d pdf_trailer_code            == pdftex_first_extension_code + 23
@d pdf_font_expand_code        == pdftex_first_extension_code + 24
@d set_random_seed_code        == pdftex_first_extension_code + 25
@d pdf_glyph_to_unicode_code   == pdftex_first_extension_code + 26
@d late_lua_node               == pdftex_first_extension_code + 27
@d save_cat_code_table_code    == pdftex_first_extension_code + 29
@d init_cat_code_table_code    == pdftex_first_extension_code + 30
@d pdf_colorstack_node         == pdftex_first_extension_code + 31
@d pdf_setmatrix_node          == pdftex_first_extension_code + 32
@d pdf_save_node               == pdftex_first_extension_code + 33
@d pdf_restore_node            == pdftex_first_extension_code + 34
@d pdftex_last_extension_code  == pdftex_first_extension_code + 34

@<Put each...@>=
primitive_tex("openout",extension,open_node,0);@/
@!@:open_out_}{\.{\\openout} primitive@>
primitive_tex("write",extension,write_node,0); write_loc:=cur_val;@/
@!@:write_}{\.{\\write} primitive@>
primitive_tex("closeout",extension,close_node,0);@/
@!@:close_out_}{\.{\\closeout} primitive@>
primitive_tex("special",extension,special_node,0);@/
@!@:special_}{\.{\\special} primitive@>
text(frozen_special):="special"; eqtb[frozen_special]:=eqtb[cur_val];@/
primitive_tex("immediate",extension,immediate_code,0);@/
@!@:immediate_}{\.{\\immediate} primitive@>
primitive_omega("localinterlinepenalty",assign_int,int_base+local_inter_line_penalty_code,int_base);@/
primitive_omega("localbrokenpenalty",assign_int,int_base+local_broken_penalty_code,int_base);@/
primitive_omega("pagedir",assign_dir,dir_base+page_direction_code,dir_base);@/
primitive_omega("bodydir",assign_dir,dir_base+body_direction_code,dir_base);@/
primitive_omega("pardir",assign_dir,dir_base+par_direction_code,dir_base);@/
primitive_omega("textdir",assign_dir,dir_base+text_direction_code,dir_base);@/
primitive_omega("mathdir",assign_dir,dir_base+math_direction_code,dir_base);@/
primitive_luatex("pageleftoffset",assign_dimen,dimen_base+page_left_offset_code,dimen_base);
primitive_luatex("pagetopoffset",assign_dimen,dimen_base+page_top_offset_code,dimen_base);
primitive_aleph("pagerightoffset",assign_dimen,dimen_base+page_right_offset_code,dimen_base);
primitive_aleph("pagebottomoffset",assign_dimen,dimen_base+page_bottom_offset_code,dimen_base);
primitive_pdftex("pdfliteral",extension,pdf_literal_node,0);@/
@!@:pdf_literal_}{\.{\\pdfliteral} primitive@>
primitive_pdftex("pdfcolorstack",extension,pdf_colorstack_node,0);@/
@!@:pdf_colorstack_}{\.{\\pdfcolorstack} primitive@>
primitive_pdftex("pdfsetmatrix",extension,pdf_setmatrix_node,0);@/
@!@:pdf_setmatrix_}{\.{\\pdfsetmatrix} primitive@>
primitive_pdftex("pdfsave",extension,pdf_save_node,0);@/
@!@:pdf_save_}{\.{\\pdfsave} primitive@>
primitive_pdftex("pdfrestore",extension,pdf_restore_node,0);@/
@!@:pdf_restore_}{\.{\\pdfrestore} primitive@>
primitive_pdftex("pdfobj",extension,pdf_obj_code,0);@/
@!@:pdf_obj_}{\.{\\pdfobj} primitive@>
primitive_pdftex("pdfrefobj",extension,pdf_refobj_node,0);@/
@!@:pdf_refobj_}{\.{\\pdfrefobj} primitive@>
primitive_pdftex("pdfxform",extension,pdf_xform_code,0);@/
@!@:pdf_xform_}{\.{\\pdfxform} primitive@>
primitive_pdftex("pdfrefxform",extension,pdf_refxform_node,0);@/
@!@:pdf_refxform_}{\.{\\pdfrefxform} primitive@>
primitive_pdftex("pdfximage",extension,pdf_ximage_code,0);@/
@!@:pdf_ximage_}{\.{\\pdfximage} primitive@>
primitive_pdftex("pdfrefximage",extension,pdf_refximage_node,0);@/
@!@:pdf_refximage_}{\.{\\pdfrefximage} primitive@>
primitive_pdftex("pdfannot",extension,pdf_annot_node,0);@/
@!@:pdf_annot_}{\.{\\pdfannot} primitive@>
primitive_pdftex("pdfstartlink",extension,pdf_start_link_node,0);@/
@!@:pdf_start_link_}{\.{\\pdfstartlink} primitive@>
primitive_pdftex("pdfendlink",extension,pdf_end_link_node,0);@/
@!@:pdf_end_link_}{\.{\\pdfendlink} primitive@>
primitive_pdftex("pdfoutline",extension,pdf_outline_code,0);@/
@!@:pdf_outline_}{\.{\\pdfoutline} primitive@>
primitive_pdftex("pdfdest",extension,pdf_dest_node,0);@/
@!@:pdf_dest_}{\.{\\pdfdest} primitive@>
primitive_pdftex("pdfthread",extension,pdf_thread_node,0);@/
@!@:pdf_thread_}{\.{\\pdfthread} primitive@>
primitive_pdftex("pdfstartthread",extension,pdf_start_thread_node,0);@/
@!@:pdf_start_thread_}{\.{\\pdfstartthread} primitive@>
primitive_pdftex("pdfendthread",extension,pdf_end_thread_node,0);@/
@!@:pdf_end_thread_}{\.{\\pdfendthread} primitive@>
primitive_pdftex("pdfsavepos",extension,pdf_save_pos_node,0);@/
@!@:pdf_save_pos_}{\.{\\pdfsavepos} primitive@>
primitive_pdftex("pdfinfo",extension,pdf_info_code,0);@/
@!@:pdf_info_}{\.{\\pdfinfo} primitive@>
primitive_pdftex("pdfcatalog",extension,pdf_catalog_code,0);@/
@!@:pdf_catalog_}{\.{\\pdfcatalog} primitive@>
primitive_pdftex("pdfnames",extension,pdf_names_code,0);@/
@!@:pdf_names_}{\.{\\pdfnames} primitive@>
primitive_pdftex("pdfincludechars",extension,pdf_include_chars_code,0);@/
@!@:pdf_include_chars_}{\.{\\pdfincludechars} primitive@>
primitive_pdftex("pdffontattr",extension,pdf_font_attr_code,0);@/
@!@:pdf_font_attr_}{\.{\\pdffontattr} primitive@>
primitive_pdftex("pdfmapfile",extension,pdf_map_file_code,0);@/
@!@:pdf_map_file_}{\.{\\pdfmapfile} primitive@>
primitive_pdftex("pdfmapline",extension,pdf_map_line_code,0);@/
@!@:pdf_map_line_}{\.{\\pdfmapline} primitive@>
primitive_pdftex("pdftrailer",extension,pdf_trailer_code,0);@/
@!@:pdf_trailer_}{\.{\\pdftrailer} primitive@>
primitive_luatex("savecatcodetable",extension,save_cat_code_table_code,0);@/
@!@:save_cat_code_table_}{\.{\\savecatcodetable} primitive@>
primitive_luatex("initcatcodetable",extension,init_cat_code_table_code,0);@/
@!@:init_cat_code_table_}{\.{\\initcatcodetable} primitive@>
primitive_pdftex("pdfsetrandomseed",extension,set_random_seed_code,0);@/
@!@:set_random_seed_code}{\.{\\pdfsetrandomseed} primitive@>
primitive_luatex("latelua",extension,late_lua_node,0);@/
@!@:late_lua_node_}{\.{\\latelua} primitive@>
primitive_pdftex("pdffontexpand",extension,pdf_font_expand_code,0);@/
@!@:pdf_font_expand_}{\.{\\pdffontexpand} primitive@>
primitive_pdftex("pdfglyphtounicode",extension,pdf_glyph_to_unicode_code,0);@/
@!@:pdf_glyph_to_unicode_}{\.{\\pdfglyphtounicode} primitive@>

@ The variable |write_loc| just introduced is used to provide an
appropriate error message in case of ``runaway'' write texts.

@<Glob...@>=
@!write_loc:pointer; {|eqtb| address of \.{\\write}}

@ When an |extension| command occurs in |main_control|, in any mode,
the |do_extension| routine is called.

@<Cases of |main_control| that are for extensions...@>=
any_mode(extension):do_extension;

@ @<Declare act...@>=
@t\4@>@<Declare procedures needed in |do_extension|@>@;
procedure do_extension;
var i,@!j,@!k:integer; {all-purpose integers}
@!p,@!q,@!r:pointer; {all-purpose pointers}
@!sn:integer; {a potential lua state name}
begin case cur_chr of
  open_node:@<Implement \.{\\openout}@>;
  write_node:@<Implement \.{\\write}@>;
  close_node:@<Implement \.{\\closeout}@>;
  special_node:@<Implement \.{\\special}@>;
  immediate_code:@<Implement \.{\\immediate}@>;
  pdf_annot_node: @<Implement \.{\\pdfannot}@>;
  pdf_catalog_code: @<Implement \.{\\pdfcatalog}@>;
  pdf_dest_node: @<Implement \.{\\pdfdest}@>;
  pdf_end_link_node: @<Implement \.{\\pdfendlink}@>;
  pdf_end_thread_node: @<Implement \.{\\pdfendthread}@>;
  pdf_font_attr_code: @<Implement \.{\\pdffontattr}@>;
  pdf_font_expand_code: @<Implement \.{\\pdffontexpand}@>;
  pdf_include_chars_code: @<Implement \.{\\pdfincludechars}@>;
  pdf_info_code: @<Implement \.{\\pdfinfo}@>;
  pdf_literal_node: @<Implement \.{\\pdfliteral}@>;
  pdf_colorstack_node: @<Implement \.{\\pdfcolorstack}@>;
  pdf_setmatrix_node: @<Implement \.{\\pdfsetmatrix}@>;
  pdf_save_node: @<Implement \.{\\pdfsave}@>;
  pdf_restore_node: @<Implement \.{\\pdfrestore}@>;
  pdf_map_file_code: @<Implement \.{\\pdfmapfile}@>;
  pdf_map_line_code: @<Implement \.{\\pdfmapline}@>;
  pdf_names_code: @<Implement \.{\\pdfnames}@>;
  pdf_obj_code: @<Implement \.{\\pdfobj}@>;
  pdf_outline_code: @<Implement \.{\\pdfoutline}@>;
  pdf_refobj_node: @<Implement \.{\\pdfrefobj}@>;
  pdf_refxform_node: @<Implement \.{\\pdfrefxform}@>;
  pdf_refximage_node: @<Implement \.{\\pdfrefximage}@>;
  pdf_save_pos_node: @<Implement \.{\\pdfsavepos}@>;
  pdf_start_link_node: @<Implement \.{\\pdfstartlink}@>;
  pdf_start_thread_node: @<Implement \.{\\pdfstartthread}@>;
  pdf_thread_node: @<Implement \.{\\pdfthread}@>;
  pdf_trailer_code: @<Implement \.{\\pdftrailer}@>;
  pdf_xform_code: @<Implement \.{\\pdfxform}@>;
  pdf_ximage_code: @<Implement \.{\\pdfximage}@>;
  save_cat_code_table_code: @<Implement \.{\\savecatcodetable}@>;
  init_cat_code_table_code: @<Implement \.{\\initcatcodetable}@>;
  set_random_seed_code: @<Implement \.{\\pdfsetrandomseed}@>;
  pdf_glyph_to_unicode_code: @<Implement \.{\\pdfglyphtounicode}@>;
  late_lua_node: @<Implement \.{\\latelua}@>;
othercases confusion("ext1")
@:this can't happen ext1}{\quad ext1@>
endcases;
end;

@ Here is a subroutine that creates a whatsit node having a given |subtype|
and a given number of words. It initializes only the first word of the whatsit,
and appends it to the current list.

@<Declare procedures needed in |do_extension|@>=
procedure new_whatsit(@!s:small_number);
var p:pointer; {the new node}
begin p:=new_node(whatsit_node,s);
vlink(tail):=p; tail:=p;
end;

@ The next subroutine uses |cur_chr| to decide what sort of whatsit is
involved, and also inserts a |write_stream| number.

@<Declare procedures needed in |do_ext...@>=
procedure new_write_whatsit(@!w:small_number);
begin new_whatsit(cur_chr);
if w<>write_node_size then scan_four_bit_int
else  begin scan_int;
  if cur_val<0 then cur_val:=17
  else if cur_val>15 then cur_val:=16;
  end;
write_stream(tail):=cur_val;
end;

@ @<Implement \.{\\openout}@>=
begin new_write_whatsit(open_node_size);
scan_optional_equals; scan_file_name;@/
open_name(tail):=cur_name; open_area(tail):=cur_area; open_ext(tail):=cur_ext;
end

@ When `\.{\\write 12\{...\}}' appears, we scan the token list `\.{\{...\}}'
without expanding its macros; the macros will be expanded later when this
token list is rescanned.

@<Implement \.{\\write}@>=
begin k:=cur_cs; new_write_whatsit(write_node_size);@/
cur_cs:=k; p:=scan_toks(false,false); write_tokens(tail):=def_ref;
end

@ @<Implement \.{\\closeout}@>=
begin new_write_whatsit(write_node_size); write_tokens(tail):=null;
end

@ When `\.{\\special\{...\}}' appears, we expand the macros in the token
list as in \.{\\xdef} and \.{\\mark}.

@<Implement \.{\\special}@>=
begin new_whatsit(special_node); write_stream(tail):=null;
p:=scan_toks(false,true); write_tokens(tail):=def_ref;
end

@ @<Implement \.{\\pdffontexpand}@>=
    read_expand_font

@ The following macros are needed for further manipulation with whatsit nodes
for \pdfTeX{} extensions (copying, destroying etc.)

@d add_action_ref(#) == incr(pdf_action_refcount(#)) {increase count of
references to this action}

@d delete_action_ref(#) == {decrease count of references to this
action; free it if there is no reference to this action}
begin
    if pdf_action_refcount(#) = null then begin
        if pdf_action_type(#) = pdf_action_user then
            delete_token_ref(pdf_action_tokens(#))
        else begin
            if pdf_action_file(#) <> null then
                delete_token_ref(pdf_action_file(#));
            if pdf_action_type(#) = pdf_action_page then
                delete_token_ref(pdf_action_tokens(#))
            else if pdf_action_named_id(#) > 0 then
                delete_token_ref(pdf_action_id(#));
        end;
        flush_node(#);
    end
    else
        decr(pdf_action_refcount(#));
end

@ We have to check whether \.{\\pdfoutput} is set for using \pdfTeX{}
  extensions.
@<Declare procedures needed in |do_ext...@>=
procedure check_pdfoutput(s: str_number; is_error : boolean);
begin
    if pdf_output <= 0 then
        begin
        if is_error then
            pdf_error(s, "not allowed in DVI mode (\pdfoutput <= 0)")
        else
            pdf_warning(s, "not allowed in DVI mode (\pdfoutput <= 0); ignoring it", true,true);
        end
end;

procedure scan_pdf_ext_toks;
begin
    call_func(scan_toks(false, true)); {like \.{\\special}}
end;

@ @<Implement \.{\\pdfliteral}@>=
begin
    check_pdfoutput("\pdfliteral", true);
    new_whatsit(pdf_literal_node);
    if scan_keyword('direct') then
        pdf_literal_mode(tail) := direct_always
    else if scan_keyword('page') then
        pdf_literal_mode(tail) := direct_page
    else
        pdf_literal_mode(tail) := set_origin;
    scan_pdf_ext_toks;
    pdf_literal_type(tail) := normal;
    pdf_literal_data(tail) := def_ref;
end

@ @<Implement \.{\\pdfcolorstack}@>=
begin
    check_pdfoutput("\pdfcolorstack", true);
    {Scan and check the stack number and store in |cur_val|}
    scan_int;
    if cur_val >= colorstackused then begin
        print_err("Unknown color stack number ");
        print_int(cur_val);
@.Unknown color stack@>
        help3("Allocate and initialize a color stack with \\pdfcolorstackinit.")@/
        ("I'll use default color stack 0 here.")@/
        ("Proceed, with fingers crossed.");
        error;
        cur_val := 0;
    end;
    if cur_val < 0 then begin
        print_err("Invalid negative color stack number");
@.Invalid negative color stack number@>
        help2("I'll use default color stack 0 here.")@/
        ("Proceed, with fingers crossed.");
        error;
        cur_val := 0;
    end;
    if scan_keyword('set') then begin
        i := colorstack_set;
    end
    else if scan_keyword('push') then begin
        i := colorstack_push;
    end
    else if scan_keyword('pop') then begin
        i := colorstack_pop;
    end
    else if scan_keyword('current') then begin
        i := colorstack_current;
    end
    else begin
        i := -1; {error}
    end;
    if i >= 0 then begin
        new_whatsit(pdf_colorstack_node);
        pdf_colorstack_stack(tail) := cur_val;
        pdf_colorstack_cmd(tail)   := i;
            pdf_colorstack_data(tail)  := null;
        if i <= colorstack_data then begin
            scan_pdf_ext_toks;
            pdf_colorstack_data(tail) := def_ref;
        end;
    end
    else begin
        print_err("Color stack action is missing");
@.Color stack action is missing@>
        help3("The expected actions for \pdfcolorstack:")@/
        ("    set, push, pop, current")@/
        ("I'll ignore the color stack command.");
        error;
    end
end

@ @<Implement \.{\\pdfsetmatrix}@>=
begin
    check_pdfoutput("\pdfsetmatrix", true);
    new_whatsit(pdf_setmatrix_node);
    scan_pdf_ext_toks;
    pdf_setmatrix_data(tail) := def_ref;
end

@ @<Implement \.{\\pdfsave}@>=
begin
    check_pdfoutput("\pdfsave", true);
    new_whatsit(pdf_save_node);
end

@ @<Implement \.{\\pdfrestore}@>=
begin
    check_pdfoutput("\pdfrestore", true);
    new_whatsit(pdf_restore_node);
end


@ @<Implement \.{\\latelua}@>=
begin
    check_pdfoutput("\latelua", true);
    new_whatsit(late_lua_node);
    if scan_keyword('name') then begin
       scan_pdf_ext_toks;
       late_lua_name(tail) := def_ref;
    end;
    sn:=0;
    @<Parse optional lua state...@>;
    if sn then late_lua_name(tail) := sn;
    call_func(scan_toks(false, false));
    late_lua_data(tail) := def_ref;
end

@ The \.{\\pdfobj} primitive is used to create a ``raw'' object in the PDF
  output file. The object contents will be hold in memory and will be written
  out only when the object is referenced by \.{\\pdfrefobj}. When \.{\\pdfobj}
  is used with \.{\\immediate}, the object contents will be written out
  immediately. Objects referenced in the current page are appended into
  |pdf_obj_list|.

@<Glob...@>=
@!pdf_last_obj: integer;

@ @<Implement \.{\\pdfobj}@>=
begin
    check_pdfoutput("\pdfobj", true);
    if scan_keyword('reserveobjnum') then begin
        @<Scan an optional space@>;
        incr(pdf_obj_count);
        pdf_create_obj(obj_type_obj, pdf_obj_count);
        pdf_last_obj := obj_ptr;
    end
    else begin
        k := -1;
        if scan_keyword('useobjnum') then begin
            scan_int;
            k := cur_val;
            if (k <= 0) or (k > obj_ptr) or (obj_data_ptr(k) <> 0) then begin
                pdf_warning("\pdfobj", "invalid object number being ignored", true, true);
                pdf_retval := -1; {signal the problem}
                k := -1; {will be generated again}
            end;
        end;
        if k < 0 then begin
            incr(pdf_obj_count);
            pdf_create_obj(obj_type_obj, pdf_obj_count);
            k := obj_ptr;
        end;
        obj_data_ptr(k) := pdf_get_mem(pdfmem_obj_size);
        if scan_keyword('stream') then begin
            obj_obj_is_stream(k) := 1;
            if scan_keyword('attr') then begin
                scan_pdf_ext_toks;
                obj_obj_stream_attr(k) := def_ref;
            end
            else
                obj_obj_stream_attr(k) := null;
        end
        else
            obj_obj_is_stream(k) := 0;
        if scan_keyword('file') then
            obj_obj_is_file(k) := 1
        else
            obj_obj_is_file(k) := 0;
        scan_pdf_ext_toks;
        obj_obj_data(k) := def_ref;
        pdf_last_obj := k;
    end;
end

@ We need to check whether the referenced object exists.

@<Declare procedures that need to be declared forward for \pdfTeX@>=
function prev_rightmost(s, e: pointer): pointer;
{finds the node preceding the rightmost node |e|; |s| is some node
before |e|}
var p: pointer;
begin
    prev_rightmost := null;
    p := s;
    if p = null then
        return;
    while vlink(p) <> e do begin
        p := vlink(p);
        if p = null then
            return;
    end;
    prev_rightmost := p;
end;

procedure pdf_check_obj(t, n: integer);
var k: integer;
begin
    k := head_tab[t];
    while (k <> 0) and (k <> n) do
        k := obj_link(k);
    if k = 0 then
        pdf_error("ext1", "cannot find referenced object");
end;

@ @<Implement \.{\\pdfrefobj}@>=
begin
    check_pdfoutput("\pdfrefobj", true);
    scan_int;
    pdf_check_obj(obj_type_obj, cur_val);
    new_whatsit(pdf_refobj_node);
    pdf_obj_objnum(tail) := cur_val;
end

@ \.{\\pdfxform} and \.{\\pdfrefxform} are similiar to \.{\\pdfobj} and
  \.{\\pdfrefobj}

@<Glob...@>=
@!pdf_last_xform: integer;

@ @<Implement \.{\\pdfxform}@>=
begin
    check_pdfoutput("\pdfxform", true);
    incr(pdf_xform_count);
    pdf_create_obj(obj_type_xform, pdf_xform_count);
    k := obj_ptr;
    obj_data_ptr(k) := pdf_get_mem(pdfmem_xform_size);
    if scan_keyword('attr') then begin
        scan_pdf_ext_toks;
        obj_xform_attr(k) := def_ref;
    end
    else
        obj_xform_attr(k) := null;
    if scan_keyword('resources') then begin
        scan_pdf_ext_toks;
        obj_xform_resources(k) := def_ref;
    end
    else
        obj_xform_resources(k) := null;
    scan_int;
        p:=box(cur_val);
    if p = null then
        pdf_error("ext1", "\pdfxform cannot be used with a void box");
    obj_xform_width(k) := width(p);
    obj_xform_height(k) := height(p);
    obj_xform_depth(k) := depth(p);
    obj_xform_box(k) := p; {save pointer to the box}
        box(cur_val):=null;
    pdf_last_xform := k;
end

@ @<Implement \.{\\pdfrefxform}@>=
begin
    check_pdfoutput("\pdfrefxform", true);
    scan_int;
    pdf_check_obj(obj_type_xform, cur_val);
    new_whatsit(pdf_refxform_node);
    pdf_xform_objnum(tail) := cur_val;
    pdf_width(tail) := obj_xform_width(cur_val);
    pdf_height(tail) := obj_xform_height(cur_val);
    pdf_depth(tail) := obj_xform_depth(cur_val);
end

@ \.{\\pdfximage} and \.{\\pdfrefximage} are similiar to \.{\\pdfxform} and
  \.{\\pdfrefxform}. As we have to scan |<rule spec>| quite often, it is better
  have a |rule_node| that holds the most recently scanned |<rule spec>|.

@<Glob...@>=
@!pdf_last_ximage: integer;
@!pdf_last_ximage_pages: integer;
@!pdf_last_ximage_colordepth: integer;
@!alt_rule: pointer;
@!warn_pdfpagebox: boolean;

@ @<Set init...@>=
alt_rule := null;
warn_pdfpagebox := true;

@ @<Declare procedures needed in |do_ext...@>=

function scan_pdf_box_spec: integer; {scans PDF pagebox specification}
begin
    scan_pdf_box_spec := 0;
    if scan_keyword('mediabox') then
        scan_pdf_box_spec := pdf_box_spec_media
    else if scan_keyword('cropbox') then
        scan_pdf_box_spec := pdf_box_spec_crop
    else if scan_keyword('bleedbox') then
        scan_pdf_box_spec := pdf_box_spec_bleed
    else if scan_keyword('trimbox') then
        scan_pdf_box_spec := pdf_box_spec_trim
    else if scan_keyword('artbox') then
        scan_pdf_box_spec := pdf_box_spec_art
end;

procedure scan_alt_rule; {scans rule spec to |alt_rule|}
label reswitch;
begin
    if alt_rule = null then
        alt_rule := new_rule;
    width(alt_rule) := null_flag;
    height(alt_rule) := null_flag;
    depth(alt_rule) := null_flag;
reswitch:
    if scan_keyword('width') then begin
        scan_normal_dimen;
        width(alt_rule) := cur_val;
        goto reswitch;
    end;
    if scan_keyword('height') then begin
        scan_normal_dimen;
        height(alt_rule) := cur_val;
        goto reswitch;
    end;
    if scan_keyword('depth') then begin
        scan_normal_dimen;
        depth(alt_rule) := cur_val;
        goto reswitch;
    end;
end;

procedure scan_image;
label reswitch;
var k, img_wd, img_ht, img_dp, ref: integer;
    named, attr: str_number;
    s: str_number;
    page, pagebox, colorspace: integer;
begin
    incr(pdf_ximage_count);
    pdf_create_obj(obj_type_ximage, pdf_ximage_count);
    k := obj_ptr;
    scan_alt_rule; {scans |<rule spec>| to |alt_rule|}
    img_wd := width(alt_rule);
    img_ht := height(alt_rule);
    img_dp := depth(alt_rule);
    attr := 0;
    named := 0;
    page := 1;
    colorspace := 0;
    if scan_keyword('attr') then begin
        scan_pdf_ext_toks;
        attr := tokens_to_string(def_ref);
        delete_token_ref(def_ref);
    end;
    if scan_keyword('named') then begin
        scan_pdf_ext_toks;
        named := tokens_to_string(def_ref);
        delete_token_ref(def_ref);
        page := 0;
    end
    else if scan_keyword('page') then begin
        scan_int;
        page := cur_val;
    end;
    if scan_keyword('colorspace') then begin
        scan_int;
        colorspace := cur_val;
    end;
    pagebox := scan_pdf_box_spec;
    if pagebox = 0 then
        pagebox := pdf_pagebox;
    scan_pdf_ext_toks;
    s := tokens_to_string(def_ref);
    delete_token_ref(def_ref);
    if pdf_option_always_use_pdfpagebox <> 0 then begin
        pdf_warning("PDF inclusion", "Primitive \pdfoptionalwaysusepdfpagebox is obsolete; use \pdfpagebox instead.", true, true);
        pdf_force_pagebox := pdf_option_always_use_pdfpagebox;
        pdf_option_always_use_pdfpagebox := 0; {warn once}
        warn_pdfpagebox := false;
    end;
    if pdf_option_pdf_inclusion_errorlevel <> 0 then begin
        pdf_warning("PDF inclusion", "Primitive \pdfoptionpdfinclusionerrorlevel is obsolete; use \pdfinclusionerrorlevel instead.", true, true);
        pdf_inclusion_errorlevel := pdf_option_pdf_inclusion_errorlevel;
        pdf_option_pdf_inclusion_errorlevel := 0; {warn once}
    end;
    if pdf_force_pagebox > 0 then begin
        if warn_pdfpagebox then begin
            pdf_warning("PDF inclusion", "Primitive \pdfforcepagebox is obsolete; use \pdfpagebox instead.", true, true);
            warn_pdfpagebox := false;
        end;
        pagebox := pdf_force_pagebox;
    end;
    if pagebox = 0 then {no pagebox specification given}
        pagebox := pdf_box_spec_crop;
    ref := read_image(k, pdf_ximage_count, s, page, named, attr, colorspace, pagebox,
                      pdf_minor_version, pdf_inclusion_errorlevel);
    flush_str(s);
    obj_data_ptr(k) := ref;
    if named <> 0 then flush_str(named);
    set_image_dimensions(ref, img_wd, img_ht, img_dp);
    if attr <> 0 then flush_str(attr);
    scale_image(ref);
    pdf_last_ximage := k;
    pdf_last_ximage_pages := image_pages(ref);
    pdf_last_ximage_colordepth := image_colordepth(ref);
end;

@ @<Implement \.{\\pdfximage}@>=
begin
    check_pdfoutput("\pdfximage", true);
    check_pdfminorversion;
    scan_image;
end

@ @<Implement \.{\\pdfrefximage}@>=
begin
    check_pdfoutput("\pdfrefximage", true);
    scan_int;
    pdf_check_obj(obj_type_ximage, cur_val);
    new_whatsit(pdf_refximage_node);
    j := obj_data_ptr(cur_val);
    pdf_ximage_idx(tail) := j;
    pdf_width(tail) := image_width(j);
    pdf_height(tail) := image_height(j);
    pdf_depth(tail) := image_depth(j);
end

@ The following function finds object with identifier |i| and type |t|.
  |i < 0| indicates that |-i| should be treated as a string number. If no
  such object exists then it will be created. This function is used mainly to
  find destination for link annotations and outlines; however it is also used
  in |pdf_ship_out| (to check whether a Page object already exists) so we need
  to declare it together with subroutines needed in |pdf_hlist_out| and
  |pdf_vlist_out|.

@<Declare procedures that need to be declared forward for \pdfTeX@>=
function find_obj(t, i: integer; byname: boolean): integer;
begin
    find_obj := avl_find_obj(t, i, byname);
end;

procedure flush_str(s: str_number); {flush a string if possible}
begin
    if flushable(s) then
        flush_string;
end;

function get_obj(t, i: integer; byname: boolean): integer;
var r: integer;
    s: str_number;
begin
    if byname > 0 then begin
        s := tokens_to_string(i);
        r := find_obj(t, s, true);
    end
    else begin
        s := 0;
        r := find_obj(t, i, false);
    end;
    if r = 0 then begin
        if byname > 0 then begin
            pdf_create_obj(t, -s);
            s := 0;
        end
        else
            pdf_create_obj(t, i);
        r := obj_ptr;
        if t = obj_type_dest then
            obj_dest_ptr(r) := null;
    end;
    if s <> 0 then
        flush_str(s);
    get_obj := r;
end;

function get_microinterval:integer;
var s,@!m:integer; {seconds and microseconds}
begin
   seconds_and_micros(s,m);
   if (s-epochseconds)>32767 then
     get_microinterval := max_integer
   else if (microseconds>m)  then
     get_microinterval := ((s-1-epochseconds)*65536)+ (((m+1000000-microseconds)/100)*65536)/10000
   else
     get_microinterval := ((s-epochseconds)*65536)  + (((m-microseconds)/100)*65536)/10000;
end;


@ @<Declare procedures needed in |do_ext...@>=
function scan_action: pointer; {read an action specification}
var p: integer;
begin
    p := new_node(action_node,0);
    scan_action := p;
    if scan_keyword('user') then
        pdf_action_type(p) := pdf_action_user
    else if scan_keyword('goto') then
        pdf_action_type(p) := pdf_action_goto
    else if scan_keyword('thread') then
        pdf_action_type(p) := pdf_action_thread
    else
        pdf_error("ext1", "action type missing");
    if pdf_action_type(p) = pdf_action_user then begin
        scan_pdf_ext_toks;
        pdf_action_tokens(p) := def_ref;
        return;
    end;
    if scan_keyword('file') then begin
        scan_pdf_ext_toks;
        pdf_action_file(p) := def_ref;
    end;
    if scan_keyword('page') then begin
        if pdf_action_type(p) <> pdf_action_goto then
            pdf_error("ext1", "only GoTo action can be used with `page'");
        pdf_action_type(p) := pdf_action_page;
        scan_int;
        if cur_val <= 0 then
            pdf_error("ext1", "page number must be positive");
        pdf_action_id(p) := cur_val;
        pdf_action_named_id(p) := 0;
        scan_pdf_ext_toks;
        pdf_action_tokens(p) := def_ref;
    end
    else if scan_keyword('name') then begin
        scan_pdf_ext_toks;
        pdf_action_named_id(p) := 1;
        pdf_action_id(p) := def_ref;
    end
    else if scan_keyword('num') then begin
        if (pdf_action_type(p) = pdf_action_goto) and
            (pdf_action_file(p) <> null) then
            pdf_error("ext1",
                "`goto' option cannot be used with both `file' and `num'");
        scan_int;
        if cur_val <= 0 then
            pdf_error("ext1", "num identifier must be positive");
        pdf_action_named_id(p) := 0;
        pdf_action_id(p) := cur_val;
    end
    else
        pdf_error("ext1", "identifier type missing");
    if scan_keyword('newwindow') then begin
        pdf_action_new_window(p) := 1;
        @<Scan an optional space@>; end
    else if scan_keyword('nonewwindow') then begin
        pdf_action_new_window(p) := 2;
        @<Scan an optional space@>; end
    else
        pdf_action_new_window(p) := 0;
    if (pdf_action_new_window(p) > 0) and
        (((pdf_action_type(p) <> pdf_action_goto) and
          (pdf_action_type(p) <> pdf_action_page)) or
         (pdf_action_file(p) = null)) then
            pdf_error("ext1",
                "`newwindow'/`nonewwindow' must be used with `goto' and `file' option");
end;

procedure new_annot_whatsit(w: small_number); {create a new whatsit node for
annotation}
begin
    new_whatsit(w);
    scan_alt_rule; {scans |<rule spec>| to |alt_rule|}
    pdf_width(tail) := width(alt_rule);
    pdf_height(tail) := height(alt_rule);
    pdf_depth(tail) := depth(alt_rule);
    if (w = pdf_thread_node) or (w = pdf_start_thread_node) then begin
        if scan_keyword('attr') then begin
            scan_pdf_ext_toks;
            pdf_thread_attr(tail) := def_ref;
        end
        else
            pdf_thread_attr(tail) := null;
    end;
end;

@ @<Glob...@>=
@!pdf_last_annot: integer;

@ @<Implement \.{\\pdfannot}@>=
begin
    check_pdfoutput("\pdfannot", true);
    if scan_keyword('reserveobjnum') then begin
        pdf_last_annot := pdf_new_objnum;
        @<Scan an optional space@>; end
    else begin
        if scan_keyword('useobjnum') then begin
            scan_int;
            k := cur_val;
            if (k <= 0) or (k > obj_ptr) or (obj_annot_ptr(k) <> 0) then
                pdf_error("ext1", "invalid object number");
        end
        else
            k := pdf_new_objnum;
        new_annot_whatsit(pdf_annot_node);
        pdf_annot_objnum(tail) := k;
        scan_pdf_ext_toks;
        pdf_annot_data(tail) := def_ref;
        pdf_last_annot := k;
    end
end

@ pdflastlink needs an extra global variable
@<Glob...@>=
@!pdf_last_link: integer;

@ @<Implement \.{\\pdfstartlink}@>=
begin
    check_pdfoutput("\pdfstartlink", true);
    if abs(mode) = vmode then
        pdf_error("ext1", "\pdfstartlink cannot be used in vertical mode");
    k := pdf_new_objnum;
    new_annot_whatsit(pdf_start_link_node);
            pdf_link_attr(tail) := null;
        if scan_keyword('attr') then begin
            scan_pdf_ext_toks;
            pdf_link_attr(tail) := def_ref;
        end;
    r := scan_action; pdf_link_action(tail) := r;
    pdf_link_objnum(tail) := k;
    pdf_last_link := k;
    {N.B.: although it is possible to set |obj_annot_ptr(k) := tail| here, it
     is not safe if nodes are later copied/destroyed/moved; a better place
     to do this is inside |do_link|, when the whatsit node is written out}
end

@ @<Implement \.{\\pdfendlink}@>=
begin
    check_pdfoutput("\pdfendlink", true);
    if abs(mode) = vmode then
        pdf_error("ext1", "\pdfendlink cannot be used in vertical mode");
    new_whatsit(pdf_end_link_node);
end

@ @<Declare procedures needed in |do_ext...@>=
function outline_list_count(p: pointer): integer; {return number of outline
entries in the same level with |p|}
var k: integer;
begin
    k := 1;
    while obj_outline_prev(p) <> 0 do begin
        incr(k);
        p := obj_outline_prev(p);
    end;
    outline_list_count := k;
end;

@ @<Implement \.{\\pdfoutline}@>=
begin
    check_pdfoutput("\pdfoutline", true);
    if scan_keyword('attr') then begin
        scan_pdf_ext_toks;
        r := def_ref;
    end
    else
        r := 0;
    p := scan_action;
    if scan_keyword('count') then begin
        scan_int;
        i := cur_val;
    end
    else
        i := 0;
    scan_pdf_ext_toks;
    q := def_ref;
    pdf_new_obj(obj_type_others, 0, 1);
    j := obj_ptr;
    write_action(p);
    pdf_end_obj;
    delete_action_ref(p);
    pdf_create_obj(obj_type_outline, 0);
    k := obj_ptr;
    obj_outline_ptr(k) := pdf_get_mem(pdfmem_outline_size);
    obj_outline_action_objnum(k) := j;
    obj_outline_count(k) := i;
    pdf_new_obj(obj_type_others, 0, 1);
    pdf_print_str_ln(tokens_to_string(q));
    flush_str(last_tokens_string);
    delete_token_ref(q);
    pdf_end_obj;
    obj_outline_title(k) := obj_ptr;
    obj_outline_prev(k) := 0;
    obj_outline_next(k) := 0;
    obj_outline_first(k) := 0;
    obj_outline_last(k) := 0;
    obj_outline_parent(k) := pdf_parent_outline;
    obj_outline_attr(k) := r;
    if pdf_first_outline = 0 then
        pdf_first_outline :=  k;
    if pdf_last_outline = 0 then begin
        if pdf_parent_outline <> 0 then
            obj_outline_first(pdf_parent_outline) := k;
    end
    else begin
        obj_outline_next(pdf_last_outline) := k;
        obj_outline_prev(k) := pdf_last_outline;
    end;
    pdf_last_outline := k;
    if obj_outline_count(k) <> 0 then begin
        pdf_parent_outline := k;
        pdf_last_outline := 0;
    end
    else if (pdf_parent_outline <> 0) and
    (outline_list_count(k) = abs(obj_outline_count(pdf_parent_outline))) then
    begin
        j := pdf_last_outline;
        repeat
            obj_outline_last(pdf_parent_outline) := j;
            j := pdf_parent_outline;
            pdf_parent_outline := obj_outline_parent(pdf_parent_outline);
        until (pdf_parent_outline = 0) or
        (outline_list_count(j) < abs(obj_outline_count(pdf_parent_outline)));
        if pdf_parent_outline = 0 then
            pdf_last_outline := pdf_first_outline
        else
            pdf_last_outline := obj_outline_first(pdf_parent_outline);
        while obj_outline_next(pdf_last_outline) <> 0 do
            pdf_last_outline := obj_outline_next(pdf_last_outline);
    end;
end

@ When a destination is created we need to check whether another destination
with the same identifier already exists and give a warning if needed.

@<Declare procedures needed in |pdf_hlist_out|, |pdf_vlist_out|@>=
procedure warn_dest_dup(id: integer; byname: small_number; s1, s2: str_number);
begin
    pdf_warning(s1, "destination with the same identifier (", false, false);
    if byname > 0 then begin
        print("name");
        print_mark(id);
    end
    else begin
        print("num");
        print_int(id);
    end;
    print(") ");
    print(s2);
    print_ln;
    show_context;
end;

@ Notice that |scan_keyword| doesn't care if two words have same prefix; so
we should be careful when scan keywords with same prefix. The main rule: if
there are two or more keywords with the same prefix, then always test in
order from the longest one to the shortest one.

@<Implement \.{\\pdfdest}@>=
begin
    check_pdfoutput("\pdfdest", true);
    q := tail;
    new_whatsit(pdf_dest_node);
    if scan_keyword('num') then begin
        scan_int;
        if cur_val <= 0 then
            pdf_error("ext1", "num identifier must be positive");
        if cur_val > max_halfword then
            pdf_error("ext1", "number too big");
        pdf_dest_id(tail) := cur_val;
        pdf_dest_named_id(tail) := 0;
    end
    else if scan_keyword('name') then begin
        scan_pdf_ext_toks;
        pdf_dest_id(tail) := def_ref;
        pdf_dest_named_id(tail) := 1;
    end
    else
        pdf_error("ext1", "identifier type missing");
    if scan_keyword('xyz') then begin
        pdf_dest_type(tail) := pdf_dest_xyz;
        if scan_keyword('zoom') then begin
            scan_int;
            if cur_val > max_halfword then
                pdf_error("ext1", "number too big");
            pdf_dest_xyz_zoom(tail) := cur_val;
        end
        else
            pdf_dest_xyz_zoom(tail) := null;
    end
    else if scan_keyword('fitbh') then
        pdf_dest_type(tail) := pdf_dest_fitbh
    else if scan_keyword('fitbv') then
        pdf_dest_type(tail) := pdf_dest_fitbv
    else if scan_keyword('fitb') then
        pdf_dest_type(tail) := pdf_dest_fitb
    else if scan_keyword('fith') then
        pdf_dest_type(tail) := pdf_dest_fith
    else if scan_keyword('fitv') then
        pdf_dest_type(tail) := pdf_dest_fitv
    else if scan_keyword('fitr') then
        pdf_dest_type(tail) := pdf_dest_fitr
    else if scan_keyword('fit') then
        pdf_dest_type(tail) := pdf_dest_fit
    else
        pdf_error("ext1", "destination type missing");
    @<Scan an optional space@>;
    if pdf_dest_type(tail) = pdf_dest_fitr then begin
        scan_alt_rule; {scans |<rule spec>| to |alt_rule|}
        pdf_width(tail) := width(alt_rule);
        pdf_height(tail) := height(alt_rule);
        pdf_depth(tail) := depth(alt_rule);
    end;
    if pdf_dest_named_id(tail) <> 0 then begin
        i := tokens_to_string(pdf_dest_id(tail));
        k := find_obj(obj_type_dest, i, true);
        flush_str(i);
    end
    else
        k := find_obj(obj_type_dest, pdf_dest_id(tail), false);
    if (k <> 0) and (obj_dest_ptr(k) <> null) then begin
        warn_dest_dup(pdf_dest_id(tail), pdf_dest_named_id(tail),
                      "ext4", "has been already used, duplicate ignored");
        flush_node_list(tail);
        tail := q;
        vlink(q) := null;
    end;
end

@ @<Declare procedures needed in |do_ext...@>=
procedure scan_thread_id;
begin
    if scan_keyword('num') then begin
        scan_int;
        if cur_val <= 0 then
            pdf_error("ext1", "num identifier must be positive");
        if cur_val > max_halfword then
            pdf_error("ext1", "number too big");
        pdf_thread_id(tail) := cur_val;
        pdf_thread_named_id(tail) := 0;
    end
    else if scan_keyword('name') then begin
        scan_pdf_ext_toks;
        pdf_thread_id(tail) := def_ref;
        pdf_thread_named_id(tail) := 1;
    end
    else
        pdf_error("ext1", "identifier type missing");
end;

@ @<Implement \.{\\pdfthread}@>=
begin
    check_pdfoutput("\pdfthread", true);
    new_annot_whatsit(pdf_thread_node);
    scan_thread_id;
end

@ @<Implement \.{\\pdfstartthread}@>=
begin
    check_pdfoutput("\pdfstartthread", true);
    new_annot_whatsit(pdf_start_thread_node);
    scan_thread_id;
end

@ @<Implement \.{\\pdfendthread}@>=
begin
    check_pdfoutput("\pdfendthread", true);
    new_whatsit(pdf_end_thread_node);
end

@ @<Glob...@>=
@!pdf_last_x_pos: integer;
@!pdf_last_y_pos: integer;

@ @<Implement \.{\\pdfsavepos}@>=
begin
    new_whatsit(pdf_save_pos_node);
end

@ To implement primitives as \.{\\pdfinfo}, \.{\\pdfcatalog} or
\.{\\pdfnames} we need to concatenate tokens lists.

@<Declare procedures needed in |do_ext...@>=
function concat_tokens(q, r: pointer): pointer; {concat |q| and |r| and
returns the result tokens list}
var p: pointer;
begin
    if q = null then begin
        concat_tokens := r;
        return;
    end;
    p := q;
    while link(p) <> null do
        p := link(p);
    link(p) := link(r);
    free_avail(r);
    concat_tokens := q;
end;

@ @<Implement \.{\\pdfinfo}@>=
begin
    check_pdfoutput("\pdfinfo", false);
    scan_pdf_ext_toks;
    if pdf_output > 0 then
        pdf_info_toks := concat_tokens(pdf_info_toks, def_ref);
end

@ @<Implement \.{\\pdfcatalog}@>=
begin
    check_pdfoutput("\pdfcatalog", false);
    scan_pdf_ext_toks;
    if pdf_output > 0 then
        pdf_catalog_toks := concat_tokens(pdf_catalog_toks, def_ref);
    if scan_keyword('openaction') then begin
        if pdf_catalog_openaction <> 0 then
            pdf_error("ext1", "duplicate of openaction")
        else begin
            p := scan_action;
            pdf_new_obj(obj_type_others, 0, 1);
            if pdf_output > 0 then
                pdf_catalog_openaction := obj_ptr;
            write_action(p);
            pdf_end_obj;
            delete_action_ref(p);
        end;
    end
end

@ @<Implement \.{\\pdfnames}@>=
begin
    check_pdfoutput("\pdfnames", true);
    scan_pdf_ext_toks;
    pdf_names_toks := concat_tokens(pdf_names_toks, def_ref);
end

@ @<Implement \.{\\pdftrailer}@>=
begin
    check_pdfoutput("\pdftrailer", false);
    scan_pdf_ext_toks;
    if pdf_output > 0 then
        pdf_trailer_toks := concat_tokens(pdf_trailer_toks, def_ref);
end

@ @<Glob...@>=
@!pdf_retval: integer; {global multi-purpose return value}

@ @<Set initial values of key variables@>=
  seconds_and_micros(epochseconds,microseconds);
  init_start_time;

@ Negative random seed values are silently converted to positive ones

@<Implement \.{\\pdfsetrandomseed}@>=
begin
  scan_int;
  if cur_val<0 then negate(cur_val);
  random_seed := cur_val;
  init_randoms(random_seed);
end

@ @<Implement \.{\\savecatcodetable}@>=
begin
  scan_int;
  if (cur_val<0)or(cur_val>@"FFFF) then begin
        print_err("Invalid \catcode table");
        help1("All \catcode table ids must be between 0 and 0xFFFF");
        error;
    end
  else begin if cur_val=cat_code_table then begin
      print_err("Invalid \catcode table");
          help1("You cannot overwrite the current \catcode table");
      error;
      end
    else
      copy_cat_codes(cat_code_table,cur_val);
    end;
end

@ @<Implement \.{\\initcatcodetable}@>=
begin
  scan_int;
  if (cur_val<0)or(cur_val>@"FFFF) then begin
        print_err("Invalid \catcode table");
        help1("All \catcode table ids must be between 0 and 0xFFFF");
        error;
    end
  else begin if cur_val=cat_code_table then begin
    print_err("Invalid \catcode table");
        help1("You cannot overwrite the current \catcode table");
        error;
    end
  else
    initex_cat_codes(cur_val);
    end;
end

@ The following subroutines are about PDF-specific font issues.

@<Declare procedures needed in |do_ext...@>=
procedure pdf_include_chars;
var s: str_number;
    k: pool_pointer; {running indices}
    f: internal_font_number;
begin
    scan_font_ident;
    f := cur_val;
    if f = null_font then
        pdf_error("font", "invalid font identifier");
    pdf_check_vf_cur_val;
    if not font_used(f) then
        pdf_init_font(f);
    scan_pdf_ext_toks;
    s := tokens_to_string(def_ref);
    delete_token_ref(def_ref);
    k := str_start_macro(s);
    while k < str_start_macro(s + 1) do begin
       pdf_mark_char(f, str_pool[k]);
       incr(k);
    end;
    flush_str(s);
end;

procedure glyph_to_unicode;
var s1, s2: str_number;
begin
    scan_pdf_ext_toks;
    s1 := tokens_to_string(def_ref);
    delete_token_ref(def_ref);
    scan_pdf_ext_toks;
    s2 := tokens_to_string(def_ref);
    delete_token_ref(def_ref);
    def_tounicode(s1, s2);
    flush_str(s2);
    flush_str(s1);
end;

@ @<Implement \.{\\pdfincludechars}@>=
begin
    check_pdfoutput("\pdfincludechars", true);
    pdf_include_chars;
end

@ @<Implement \.{\\pdfglyphtounicode}@>=
begin
    glyph_to_unicode;
end

@ A change from \THANH's original code: the font attributes are simply
initialized to zero now, this is easier to deal with from C than an
empty \TeX{} string, and surely nobody will want to set
\.{\\pdffontattr} to a string containing a single zero, as that
would be nonsensical in the PDF output.

@<Implement \.{\\pdffontattr}@>=
begin
    check_pdfoutput("\pdffontattr", true);
    scan_font_ident;
    k := cur_val;
    if k = null_font then
        pdf_error("font", "invalid font identifier");
    scan_pdf_ext_toks;
    set_pdf_font_attr(k, tokens_to_string(def_ref));
    if length(pdf_font_attr(k)) = 0 then begin
      flush_string;
      set_pdf_font_attr(k,0);
      end;
end

@ @<Implement \.{\\pdfmapfile}@>=
begin
    check_pdfoutput("\pdfmapfile", true);
    scan_pdf_ext_toks;
    pdfmapfile(def_ref);
    delete_token_ref(def_ref);
end

@ @<Implement \.{\\pdfmapline}@>=
begin
    check_pdfoutput("\pdfmapline", true);
    scan_pdf_ext_toks;
    pdfmapline(def_ref);
    delete_token_ref(def_ref);
end

@ The following function are needed for outputing article thread.

@<Declare procedures needed in |do_ext...@>=
procedure thread_title(thread: integer);
begin
    pdf_print("/Title (");
    if obj_info(thread) < 0 then
        pdf_print(-obj_info(thread))
    else
        pdf_print_int(obj_info(thread));
    pdf_print_ln(")");
end;

procedure pdf_fix_thread(thread: integer);
var a: pointer;
begin
    pdf_warning("thread", "destination ", false, false);
    if obj_info(thread) < 0 then begin
        print("name{");
        print(-obj_info(thread));
        print("}");
    end
    else begin
        print("num");
        print_int(obj_info(thread));
    end;
    print(" has been referenced but does not exist, replaced by a fixed one");
    print_ln; print_ln;
    pdf_new_dict(obj_type_others, 0, 0);
    a := obj_ptr;
    pdf_indirect_ln("T", thread);
    pdf_indirect_ln("V", a);
    pdf_indirect_ln("N", a);
    pdf_indirect_ln("P", head_tab[obj_type_page]);
    pdf_print("/R [0 0 ");
    pdf_print_bp(page_width); pdf_out(" ");
    pdf_print_bp(page_height);
    pdf_print_ln("]");
    pdf_end_dict;
    pdf_begin_dict(thread, 1);
    pdf_print_ln("/I << ");
    thread_title(thread);
    pdf_print_ln(">>");
    pdf_indirect_ln("F", a);
    pdf_end_dict;
end;

procedure out_thread(thread: integer);
var a, b: pointer;
    last_attr: integer;
begin
    if obj_thread_first(thread) = 0 then begin
        pdf_fix_thread(thread);
        return;
    end;
    pdf_begin_dict(thread, 1);
    a := obj_thread_first(thread);
    b := a;
    last_attr := 0;
    repeat
        if obj_bead_attr(a) <> 0 then
            last_attr := obj_bead_attr(a);
        a := obj_bead_next(a);
    until a = b;
    if last_attr <> 0 then
        pdf_print_ln(last_attr)
    else begin
        pdf_print_ln("/I << ");
        thread_title(thread);
        pdf_print_ln(">>");
    end;
    pdf_indirect_ln("F", a);
    pdf_end_dict;
    repeat
        pdf_begin_dict(a, 1);
        if a = b then
            pdf_indirect_ln("T", thread);
        pdf_indirect_ln("V", obj_bead_prev(a));
        pdf_indirect_ln("N", obj_bead_next(a));
        pdf_indirect_ln("P", obj_bead_page(a));
        pdf_indirect_ln("R", obj_bead_rect(a));
        pdf_end_dict;
        a := obj_bead_next(a);
    until a = b;
end;


@ Three extra node types carry information from |main_control|.

@ |cancel_boundary_nodes| indicate that the next left boundary be
ignored. These are created by the \.{\\noboundary} command in
horizontal mode.

@d cancel_boundary_node==pdf_restore_node+1
@d cancel_boundary_size==3

@<Append a |cancel_boundary_node| @>=
begin new_whatsit(cancel_boundary_node);
end

@ User defined whatsits can be inserted into node lists to pass data
along from one lua call to anotherb without interference from the
typesetting engine itself. Each has an id, a type, and a value. The
type of the value depends on the |user_node_type| field.

@d user_defined_node==cancel_boundary_node+1
@d user_node_id(#)==vlink(#+2)
@d user_node_type(#)==vinfo(#+2)
@d user_node_value(#)==vinfo(#+3)


@ @<Incorporate a whatsit node into a vbox@>=
if (subtype(p) = pdf_refxform_node) or (subtype(p) = pdf_refximage_node) then
begin x:=x+d+pdf_height(p); d:=pdf_depth(p);
s:=0;
if pdf_width(p)+s>w then w:=pdf_width(p)+s;
end

@ @<Incorporate a whatsit node into an hbox@>=
begin
if subtype(p)=dir_node then
  begin
  @<DIR: Adjust the dir stack for the |hpack| routine@>;
  end
else begin
if (subtype(p) = pdf_refxform_node) or (subtype(p) = pdf_refximage_node) then
begin x:=x+pdf_width(p);
s:=0;
if pdf_height(p)-s>h then h:=pdf_height(p)-s;
if pdf_depth(p)+s>d then d:=pdf_depth(p)+s;
end;
end;
end

@ @<Prepare to move whatsit |p| to the current page, then |goto contribute|@>=
begin
  if (subtype(p) = pdf_refxform_node) or (subtype(p) = pdf_refximage_node) then
  begin page_total:=page_total+page_depth+pdf_height(p);
  page_depth:=pdf_depth(p);
  end;
  goto contribute;
end

@ @<Process whatsit |p| in |vert_break| loop, |goto not_found|@>=
begin
  if (subtype(p) = pdf_refxform_node) or (subtype(p) = pdf_refximage_node) then
  begin cur_height:=cur_height+prev_dp+pdf_height(p); prev_dp:=pdf_depth(p);
  end;
  goto not_found;
end

@ @<Output the whatsit node |p| in a vlist@>=
out_what(p)

@ @<Output the whatsit node |p| in an hlist@>=
if subtype(p)<>dir_node then out_what(p)
else @<Output a reflection instruction if the direction has changed@>

@ After all this preliminary shuffling, we come finally to the routines
that actually send out the requested data. Let's do \.{\\special} first
(it's easier).

@<Declare procedures needed in |hlist_out|, |vlist_out|@>=
procedure special_out(@!p:pointer);
var old_setting:0..max_selector; {holds print |selector|}
@!k:pool_pointer; {index into |str_pool|}
begin synch_dvi_with_cur;@/
old_setting:=selector; selector:=new_string;
show_token_list(link(write_tokens(p)),null,pool_size-pool_ptr);
selector:=old_setting;
str_room(1);
if cur_length<256 then
  begin dvi_out(xxx1); dvi_out(cur_length);
  end
else  begin dvi_out(xxx4); dvi_four(cur_length);
  end;
for k:=str_start_macro(str_ptr) to pool_ptr-1 do dvi_out(so(str_pool[k]));
pool_ptr:=str_start_macro(str_ptr); {erase the string}
end;

@ To write a token list, we must run it through \TeX's scanner, expanding
macros and \.{\\the} and \.{\\number}, etc. This might cause runaways,
if a delimited macro parameter isn't matched, and runaways would be
extremely confusing since we are calling on \TeX's scanner in the middle
of a \.{\\shipout} command. Therefore we will put a dummy control sequence as
a ``stopper,'' right after the token list. This control sequence is
artificially defined to be \.{\\outer}.
@:end_write_}{\.{\\endwrite}@>

@<Initialize table...@>=
text(end_write):="endwrite"; eq_level(end_write):=level_one;
eq_type(end_write):=outer_call; equiv(end_write):=null;

@ @<Declare procedures needed in |hlist_out|, |vlist_out|@>=
procedure write_out(@!p:pointer);
var old_setting:0..max_selector; {holds print |selector|}
@!old_mode:integer; {saved |mode|}
@!j:small_number; {write stream number}
@!q,@!r:pointer; {temporary variables for list manipulation}
begin @<Expand macros in the token list
  and make |link(def_ref)| point to the result@>;
old_setting:=selector; j:=write_stream(p);
if write_open[j] then selector:=j
else  begin {write to the terminal if file isn't open}
  if (j=17)and(selector=term_and_log) then selector:=log_only;
  print_nl("");
  end;
token_show(def_ref); print_ln;
flush_list(def_ref); selector:=old_setting;
end;
procedure expand_late_lua(@!p:pointer);
var @!old_mode:integer; {saved |mode|}
@!q,@!r:pointer; {temporary variables for list manipulation}
begin @<Expand macros in the token list
  and make |link(def_ref)| point to the result@>;
end;


@ The final line of this routine is slightly subtle; at least, the author
didn't think about it until getting burnt! There is a used-up token list
@^Knuth, Donald Ervin@>
on the stack, namely the one that contained |end_write_token|. (We
insert this artificial `\.{\\endwrite}' to prevent runaways, as explained
above.) If it were not removed, and if there were numerous writes on a
single page, the stack would overflow.

@d end_write_token==cs_token_flag+end_write

@<Expand macros in the token list and...@>=
q:=get_avail; info(q):=right_brace_token+"}";@/
r:=get_avail; link(q):=r; info(r):=end_write_token; ins_list(q);@/
begin_token_list(write_tokens(p),write_text);@/
q:=get_avail; info(q):=left_brace_token+"{"; ins_list(q);
{now we're ready to scan
  `\.\{$\langle\,$token list$\,\rangle$\.{\} \\endwrite}'}
old_mode:=mode; mode:=0;
  {disable \.{\\prevdepth}, \.{\\spacefactor}, \.{\\lastskip}, \.{\\prevgraf}}
cur_cs:=write_loc; q:=scan_toks(false,true); {expand macros, etc.}
get_token;@+if cur_tok<>end_write_token then
  @<Recover from an unbalanced write command@>;
mode:=old_mode;
end_token_list {conserve stack space}

@ @<Recover from an unbalanced write command@>=
begin print_err("Unbalanced write command");
@.Unbalanced write...@>
help2("On this page there's a \write with fewer real {'s than }'s.")@/
("I can't handle that very well; good luck."); error;
repeat get_token;
until cur_tok=end_write_token;
end

@ The |out_what| procedure takes care of outputting whatsit nodes for
|vlist_out| and |hlist_out|\kern-.3pt.

@<Declare procedures needed in |hlist_out|, |vlist_out|@>=
procedure out_what(@!p:pointer);
var j:small_number; {write stream number}
begin case subtype(p) of
open_node,write_node,close_node:@<Do some work that has been queued up
  for \.{\\write}@>;
special_node:special_out(p);
pdf_save_pos_node:
  @<Save current position@>;
local_par_node:do_nothing;
cancel_boundary_node: do_nothing;
user_defined_node: do_nothing;
othercases  confusion("ext4") {TH: those will be pdf extension nodes in dvi mode, most likely}
@:this can't happen ext4}{\quad ext4@>
endcases;
end;

@ @<Save current position@>=
begin
    synch_pos_with_cur;
    pdf_last_x_pos := pos.h;
    pdf_last_y_pos := pos.v;
end

@ We don't implement \.{\\write} inside of leaders. (The reason is that
the number of times a leader box appears might be different in different
implementations, due to machine-dependent rounding in the glue calculations.)
@^leaders@>

@<Do some work that has been queued up...@>=
if not doing_leaders then
  begin j:=write_stream(p);
  if subtype(p)=write_node then write_out(p)
  else  begin if write_open[j] then lua_a_close_out(write_file[j]);
    if subtype(p)=close_node then write_open[j]:=false
    else if j<16 then
      begin cur_name:=open_name(p); cur_area:=open_area(p);
      cur_ext:=open_ext(p);
      if cur_ext="" then cur_ext:=".tex";
      pack_cur_name;
      while not lua_a_open_out(write_file[j],(j+1)) do
        prompt_file_name('output file name','.tex');
      write_file[j]:= name_file_pointer;
      write_open[j]:=true;
      end;
    end;
  end

@ The presence of `\.{\\immediate}' causes the |do_extension| procedure
to descend to one level of recursion. Nothing happens unless \.{\\immediate}
is followed by `\.{\\openout}', `\.{\\write}', or `\.{\\closeout}'.
@^recursion@>

@<Implement \.{\\immediate}@>=
begin get_x_token;
if cur_cmd=extension then begin
    if cur_chr<=close_node then
      begin p:=tail; do_extension; {append a whatsit node}
      out_what(tail); {do the action immediately}
      flush_node_list(tail); tail:=p; vlink(p):=null;
      end
    else case cur_chr of
        pdf_obj_code: begin
            do_extension; {scan object and set |pdf_last_obj|}
            if obj_data_ptr(pdf_last_obj) = 0 then {this object has not been initialized yet}
                pdf_error("ext1", "`\pdfobj reserveobjnum' cannot be used with \immediate");
            pdf_write_obj(pdf_last_obj);
        end;
        pdf_xform_code: begin
            do_extension; {scan form and set |pdf_last_xform|}
            pdf_cur_form := pdf_last_xform;
            pdf_ship_out(obj_xform_box(pdf_last_xform), false);
        end;
        pdf_ximage_code: begin
            do_extension; {scan image and set |pdf_last_ximage|}
            pdf_write_image(pdf_last_ximage);
        end;
        othercases back_input
    endcases;
end
else
    back_input;
end

@ @<Finish the extensions@>=
for k:=0 to 15 do if write_open[k] then lua_a_close_out(write_file[k])

@
@d local_pen_inter(#)==vinfo(#+2) {\.{\\localinterlinepenalty}}
@d local_pen_broken(#)==vlink(#+2) {\.{\\localbrokenpenalty}}
@d local_box_left(#)==vlink(#+3) {\.{\\localleftbox}}
@d local_box_left_width(#)==vinfo(#+3)
@d local_box_right(#)==vlink(#+4) {\.{\\localleftbox}}
@d local_box_right_width(#)==vinfo(#+4)
@d local_par_dir(#)==vinfo(#+5)

@<LOCAL: Declare |make_local_par_node|@>=
function make_local_par_node:pointer;
{This function creates a |local_paragraph| node}
var p,q:pointer;
begin
p:=new_node(whatsit_node,local_par_node);
local_pen_inter(p):=local_inter_line_penalty;
local_pen_broken(p):=local_broken_penalty;
if local_left_box<>null then begin
  q:=copy_node_list(local_left_box); local_box_left(p):=q;
  local_box_left_width(p):=width(local_left_box);
  end;
if local_right_box<>null then begin
  q:=copy_node_list(local_right_box); local_box_right(p):=q;
  local_box_right_width(p):=width(local_right_box);
  end;
local_par_dir(p):=par_direction;
make_local_par_node:=p;
end

@ @<LOCAL: Add local paragraph node@>=
begin tail_append(make_local_par_node) end

@ @<DIR: Assign direction codes@>=
case cur_chr of
dir_base+page_direction_code: begin
    scan_direction;
    eq_word_define(dir_base+page_direction_code,cur_val);
  end;
dir_base+body_direction_code: begin
    scan_direction;
    eq_word_define(dir_base+body_direction_code,cur_val);
  end;
dir_base+par_direction_code: begin
  scan_direction;
  eq_word_define(dir_base+par_direction_code,cur_val);
  end;
dir_base+text_direction_code: begin scan_direction;
  if (no_local_dirs>0) and (abs(mode)=hmode) then begin
    @<DIR: Add local dir node@>;
    dir_dir(tail):=dir_dir(tail);
    end;
  if dir_level(text_dir_ptr)=cur_level then
    @<DIR: Remove from |text_dir_ptr|@>;
  eq_word_define(dir_base+text_direction_code,cur_val);
  @<DIR: Add to |text_dir_ptr|@>;
  if abs(mode)=hmode then
    begin
    @<DIR: Add local dir node@>;
    dir_level(tail):=cur_level;
    end;
  eq_word_define(int_base+no_local_dirs_code,no_local_dirs+1);
  eq_word_define(int_base+level_local_dir_code,cur_level);
  end;
dir_base+math_direction_code: begin scan_direction;
  eq_word_define(dir_base+math_direction_code,cur_val);
  end;
end;

@
@d push_dir(#)==
begin dir_tmp:=new_dir(#);
vlink(dir_tmp):=dir_ptr;
dir_ptr:=dir_tmp;
end

@d push_dir_node(#)==
begin dir_tmp:=copy_node(#);
vlink(dir_tmp):=dir_ptr;
dir_ptr:=dir_tmp;
end

@d pop_dir_node==
begin dir_tmp:=dir_ptr;
dir_ptr:=vlink(dir_tmp);
flush_node(dir_tmp);
end

@ @<DIR: Declare |new_dir|@>=
function new_dir(s:small_number): pointer;
var p:pointer; {the new node}
begin p:=new_node(whatsit_node,dir_node);
dir_dir(p):=s; dir_dvi_ptr(p):=-1;
dir_level(p):=cur_level; new_dir:=p;
end

@ @<DIR: Add local dir node@>=
tail_append(new_dir(text_direction))

@ @<DIR: Adjust the dir stack for the |hpack| routine@>=
begin
if dir_dir(p)>=0 then begin
  hpack_dir:=dir_dir(p);
  push_dir_node(p);
  end
else begin
  pop_dir_node;
  if dir_ptr<>null then
    hpack_dir:=dir_dir(dir_ptr);
  end
end

@ @<DIR: Reset |dir_ptr|@>=
begin
 while dir_ptr<>null do
  pop_dir_node
end

@ @<DIR: Adjust |text_dir_ptr| for |scan_spec|@>=
begin
if spec_direction<>-1 then begin
  saved(4):=text_dir_ptr;
  text_dir_ptr:=new_dir(spec_direction);
  end
else saved(4):=null;
end

@ @<DIR: Adjust back |text_dir_ptr| for |scan_spec|@>=
begin
flush_node_list(text_dir_ptr);
text_dir_ptr:=saved(4);
end

@ @<DIR: Add to |text_dir_ptr|@>=
begin
text_dir_tmp:=new_dir(text_direction);
vlink(text_dir_tmp):=text_dir_ptr;
text_dir_ptr:=text_dir_tmp;
end

@ @<DIR: Remove from |text_dir_ptr|@>=
begin
text_dir_tmp:=vlink(text_dir_ptr);
flush_node(text_dir_ptr);
text_dir_ptr:=text_dir_tmp;
end

@ @<DIR: Initialize |text_dir_ptr|@>=
begin
text_dir_ptr:=new_dir(0);
end

@ @<DIR: Initialize |dir_ptr| for |ship_out|@>=
begin dir_ptr:=null; push_dir(dvi_direction);
dir_dvi_ptr(dir_ptr):=dvi_ptr;
end

@ @<Output a reflection instruction if the direction has changed@>=
begin
  if dir_dir(p)>=0 then begin
    push_dir_node(p);
    @<(PDF) Calculate the needed width to the matching |enddir|, and store it in |w|, as
        well as in the enddir's |dir_dvi_h|@>;
    if (dir_opposite(dir_secondary[dir_dir(dir_ptr)])(dir_secondary[dvi_direction]))
    or (dir_eq(dir_secondary[dir_dir(dir_ptr)])(dir_secondary[dvi_direction]))
    then begin
        dir_cur_h(temp_ptr) := cur.h + w;
        if dir_opposite(dir_secondary[dir_dir(dir_ptr)])(dir_secondary[dvi_direction]) then
            cur.h := cur.h + w;
    end else
        dir_cur_h(temp_ptr) := cur.h;
    dir_cur_v(temp_ptr) := cur.v;
    dir_box_pos_h(temp_ptr) := box_pos.h;
    dir_box_pos_v(temp_ptr) := box_pos.v;
    synch_pos_with_cur; {no need for |synch_dvi_with_cur|, as there is no DVI grouping}
    box_pos := pos; {fake a nested |hlist_out|}
    set_to_zero(cur);
    dvi_direction:=dir_dir(dir_ptr);
  end
  else begin
    pop_dir_node;
    box_pos.h := dir_box_pos_h(p);
    box_pos.v := dir_box_pos_v(p);
    cur.h := dir_cur_h(p);
    cur.v := dir_cur_v(p);
    if dir_ptr<>null then
      dvi_direction:=dir_dir(dir_ptr)
    else
      dvi_direction:=0;
  end
end

@ This code scans forward to the ending |dir_node| while keeping
track of the needed width in |w|. When it finds the node that will end
this segment, it stores the accumulated with in the |dir_dvi_h| field
of that end node, so that when that node is found later in the
processing, the correct glue correction can be applied.

@p
function simple_advance_width(p:halfword):scaled;
var q:halfword;
@!w:scaled;
begin
  q:=p; w:=0;
  while (q<>null) and (vlink(q)<>null) do begin
    q:=vlink(q);
    if is_char_node(q) then begin
      w:=w+glyph_width(q);
      end
    else begin
      case type(q) of
      hlist_node_case,vlist_node_case,rule_node_case,
      margin_kern_node_case,kern_node_case:
        w:=w+width(q);
      disc_node_case: if vlink(no_break(q))<>null then begin
        w:=w+simple_advance_width(no_break(q));
        end;
      othercases do_nothing;
      endcases;
    end;
  end;
  simple_advance_width:=w;
end;


@ @<(PDF) Calculate the needed width to the matching |enddir|...@>=
begin
  q:=p; w:=0;
  save_cur_g:=cur_g;
  save_cur_glue:=cur_glue;
  { to me, it looks like the next is needed. but Aleph doesn't do that,
   so let us not do it either }
  {|w:=w-cur_g; cur_glue:=0;|}
  dir_nest:=1;
  while (q<>null) and (vlink(q)<>null) do begin
        q:=vlink(q);
    if is_char_node(q) then begin
      w:=w+glyph_width(q); {TODO no vertical support for now}
      end
    else begin
      case type(q) of
      hlist_node_case,vlist_node_case,rule_node_case,
      margin_kern_node_case,kern_node_case:w:=w+width(q);
      glue_node_case: begin
        g:=glue_ptr(q);
        w:=w+width(g)-cur_g;
        if g_sign<>normal then
          begin if g_sign=stretching then
            begin if stretch_order(g)=g_order then
              begin cur_glue:=cur_glue+stretch(g);
              vet_glue(float(glue_set(this_box))*cur_glue);
              cur_g:=round(glue_temp);
              end;
            end
          else if shrink_order(g)=g_order then
             begin cur_glue:=cur_glue-shrink(g);
             vet_glue(float(glue_set(this_box))*cur_glue);
             cur_g:=round(glue_temp);
             end;
          end;
        w:=w+cur_g;
        end;
      disc_node_case: if vlink(no_break(q))<>null then begin
        w:=w+simple_advance_width(no_break(q));
        end;
      math_node_case: w:=w+surround(q);
      whatsit_node_case: begin
        if subtype(q)=dir_node then begin
          if dir_dir(q)>=0 then incr(dir_nest) else decr(dir_nest);
          if dir_nest=0 then begin
            dir_dvi_h(q) := w;
            temp_ptr := q;
            q:=null;
            end;
          end
        else if (subtype(q) = pdf_refxform_node) or
                (subtype(q) = pdf_refximage_node) then
         w:=w+pdf_width(q);
      end;
      othercases do_nothing;
      endcases;
    end;
  end;
  cur_g:=save_cur_g;
  cur_glue:=save_cur_glue;
end


@ Shipping out PDF marks.

@<Types...@>=
dest_name_entry = record
    objname: str_number; {destination name}
    objnum: integer; {destination object number}
end;

@ @<Glob...@>=
@!cur_page_size: scaledpos; {width and height of page being shipped}
@!pdf_obj_list: pointer; {list of objects in the current page}
@!pdf_xform_list: pointer; {list of forms in the current page}
@!pdf_ximage_list: pointer; {list of images in the current page}
@!last_thread: pointer; {pointer to the last thread}
@!pdf_thread_ht, pdf_thread_dp, pdf_thread_wd: scaled; {dimensions of the last
thread}
@!pdf_last_thread_id: halfword; {identifier of the last thread}
@!pdf_last_thread_named_id: boolean; {is identifier of the last thread named}
@!pdf_thread_level: integer; {depth of nesting of box containing the last thread}
@!pdf_annot_list: pointer; {list of annotations in the current page}
@!pdf_link_list: pointer; {list of link annotations in the current page}
@!pdf_dest_list: pointer; {list of destinations in the current page}
@!pdf_bead_list: pointer; {list of thread beads in the current page}
@!pdf_obj_count: integer; {counter of objects}
@!pdf_xform_count: integer; {counter of forms}
@!pdf_ximage_count: integer; {counter of images}
@!pdf_cur_form: integer; {the form being output}
@!pdf_first_outline, pdf_last_outline, pdf_parent_outline: integer;
@!pdf_info_toks: pointer; {additional keys of Info dictionary}
@!pdf_catalog_toks: pointer; {additional keys of Catalog dictionary}
@!pdf_catalog_openaction: integer;
@!pdf_names_toks: pointer; {additional keys of Names dictionary}
@!pdf_dest_names_ptr: integer; {first unused position in |dest_names|}
@!dest_names_size: integer; {maximum number of names in name tree of PDF output file}
@!dest_names: ^dest_name_entry;
@!pk_dpi: integer; {PK pixel density value from \.{texmf.cnf}}
@!image_orig_x, image_orig_y: integer; {origin of cropped PDF images}
@!pdf_trailer_toks: pointer; {additional keys of Trailer dictionary}

@ @<Set init...@>=
pdf_first_outline:= 0;
pdf_last_outline:= 0;
pdf_parent_outline:= 0;
pdf_obj_count := 0;
pdf_xform_count := 0;
pdf_ximage_count := 0;
pdf_dest_names_ptr := 0;
pdf_info_toks := null;
pdf_catalog_toks := null;
pdf_names_toks := null;
pdf_catalog_openaction := 0;
pdf_trailer_toks := null;

@ The following procedures are needed for outputing whatsit nodes for
\pdfTeX{}.

@<Declare procedures needed in |pdf_hlist_out|, |pdf_vlist_out|@>=
procedure write_action(p: pointer); {write an action specification}
var s: str_number;
    d: integer;
begin d:=0;
    if pdf_action_type(p) = pdf_action_user then begin
        pdf_print_toks_ln(pdf_action_tokens(p));
        return;
    end;
    pdf_print("<< ");
    if pdf_action_file(p) <> null then begin
        pdf_print("/F ");
        s := tokens_to_string(pdf_action_file(p));
        if (str_pool[str_start_macro(s)] = 40) and
           (str_pool[str_start_macro(s) + length(s) - 1] = 41) then
            pdf_print(s)
        else begin
            pdf_print_str(s);
        end;
        flush_str(s);
        pdf_print(" ");
        if pdf_action_new_window(p) > 0 then begin
            pdf_print("/NewWindow ");
            if pdf_action_new_window(p) = 1 then
                pdf_print("true ")
            else
                pdf_print("false ");
        end;
    end;
    case pdf_action_type(p) of
    pdf_action_page: begin
        if pdf_action_file(p) = null then begin
            pdf_print("/S /GoTo /D [");
            pdf_print_int(get_obj(obj_type_page, pdf_action_id(p), false));
            pdf_print(" 0 R");
        end
        else begin
            pdf_print("/S /GoToR /D [");
            pdf_print_int(pdf_action_id(p) - 1);
        end;
        pdf_out(" ");
        pdf_print(tokens_to_string(pdf_action_tokens(p)));
        flush_str(last_tokens_string);
        pdf_out("]");
    end;
    pdf_action_goto: begin
        if pdf_action_file(p) = null then begin
            pdf_print("/S /GoTo ");
            d := get_obj(obj_type_dest, pdf_action_id(p),
                         pdf_action_named_id(p));
        end
        else
            pdf_print("/S /GoToR ");
        if pdf_action_named_id(p) > 0 then begin
            pdf_str_entry("D", tokens_to_string(pdf_action_id(p)));
            flush_str(last_tokens_string);
        end
        else if pdf_action_file(p) = null then
            pdf _indirect("D", d)
        else
            pdf_error("ext4", "`goto' option cannot be used with both `file' and `num'");
    end;
    pdf_action_thread: begin
        pdf_print("/S /Thread ");
        if pdf_action_file(p) = null then
            d := get_obj(obj_type_thread, pdf_action_id(p),
                         pdf_action_named_id(p));
        if pdf_action_named_id(p) > 0 then begin
            pdf_str_entry("D", tokens_to_string(pdf_action_id(p)));
            flush_str(last_tokens_string);
        end
        else if pdf_action_file(p) = null then
            pdf_indirect("D", d)
        else
            pdf_int_entry("D", pdf_action_id(p));
    end;
    endcases;
    pdf_print_ln(" >>");
end;

procedure set_rect_dimens(p, parent_box: pointer; x, y, wd, ht, dp, margin: scaled);
var ll, ur, pos_ll, pos_ur, tmp: scaledpos;
begin
    ll.h := cur.h;
    if is_running(dp) then
        ll.v := y + depth(parent_box)
    else
        ll.v := cur.v + dp;
    if is_running(wd) then
        ur.h := x + width(parent_box)
    else
        ur.h := cur.h + wd;
    if is_running(ht) then
        ur.v := y - height(parent_box)
    else
        ur.v := cur.v - ht;
    pos_ll := synch_p_with_c(ll);
    pos_ur := synch_p_with_c(ur);
    if pos_ll.h > pos_ur.h then begin
        tmp.h := pos_ll.h; pos_ll.h := pos_ur.h; pos_ur.h := tmp.h; end;
    if pos_ll.v > pos_ur.v then begin
        tmp.v := pos_ll.v; pos_ll.v := pos_ur.v; pos_ur.v := tmp.v; end;
    if is_shipping_page and matrixused then begin
        matrixtransformrect(pos_ll.h, pos_ll.v, pos_ur.h, pos_ur.v);
        pos_ll.h := getllx;
        pos_ll.v := getlly;
        pos_ur.h := geturx;
        pos_ur.v := getury;
    end;
    pdf_ann_left(p) := pos_ll.h - margin;
    pdf_ann_bottom(p) := pos_ll.v - margin;
    pdf_ann_right(p) := pos_ur.h + margin;
    pdf_ann_top(p) := pos_ur.v + margin;
end;

procedure do_annot(p, parent_box: pointer; x, y: scaled);
begin
    if not is_shipping_page then
        pdf_error("ext4", "annotations cannot be inside an XForm");
    if doing_leaders then
        return;
    if is_obj_scheduled(pdf_annot_objnum(p)) then
        pdf_annot_objnum(p) := pdf_new_objnum;
    set_rect_dimens(p, parent_box, x, y,
                    pdf_width(p), pdf_height(p), pdf_depth(p), 0);
    obj_annot_ptr(pdf_annot_objnum(p)) := p;
    pdf_append_list(pdf_annot_objnum(p))(pdf_annot_list);
    set_obj_scheduled(pdf_annot_objnum(p));
end;

@ To implement nested link annotations, we need a stack to hold copy of
|pdf_start_link_node|'s that are being written out, together with their box
nesting level.

@d pdf_link_stack_top == pdf_link_stack[pdf_link_stack_ptr]

@<Constants...@>=
@!pdf_max_link_level = 10; {maximum depth of link nesting}

@ @<Types...@>=
@!pdf_link_stack_record = record
    nesting_level: integer;
    link_node: pointer; {holds a copy of the corresponding |pdf_start_link_node|}
    ref_link_node: pointer; {points to original |pdf_start_link_node|, or a
                             copy of |link_node| created by |append_link| in
                             case of multi-line link}
end;

@ @<Glob...@>=
@!pdf_link_stack: array[1..pdf_max_link_level] of pdf_link_stack_record;
@!pdf_link_stack_ptr: small_number;

@ @<Set init...@>=
pdf_link_stack_ptr := 0;

@ @<Declare procedures needed in |pdf_hlist_out|, |pdf_vlist_out|@>=
procedure push_link_level(p: pointer);
begin
    if pdf_link_stack_ptr >= pdf_max_link_level then
        overflow("pdf link stack size", pdf_max_link_level);
    pdfassert((type(p) = whatsit_node) and (subtype(p) = pdf_start_link_node));
    incr(pdf_link_stack_ptr);
    pdf_link_stack_top.nesting_level := cur_s;
    pdf_link_stack_top.link_node := copy_node_list(p);
    pdf_link_stack_top.ref_link_node := p;
end;

procedure pop_link_level;
begin
    pdfassert(pdf_link_stack_ptr > 0);
    flush_node_list(pdf_link_stack_top.link_node);
    decr(pdf_link_stack_ptr);
end;

procedure do_link(p, parent_box: pointer; x, y: scaled);
begin
    if not is_shipping_page then
        pdf_error("ext4", "link annotations cannot be inside an XForm");
    pdfassert(type(parent_box) = hlist_node);
    if is_obj_scheduled(pdf_link_objnum(p)) then
        pdf_link_objnum(p) := pdf_new_objnum;
    push_link_level(p);
    set_rect_dimens(p, parent_box, x, y,
                    pdf_width(p), pdf_height(p), pdf_depth(p),
                    pdf_link_margin);
    obj_annot_ptr(pdf_link_objnum(p)) := p; {the reference for the pdf annot object
                                             must be set here}
    pdf_append_list(pdf_link_objnum(p))(pdf_link_list);
    set_obj_scheduled(pdf_link_objnum(p));
end;

procedure end_link;
var p: pointer;
tmp1, tmp2: scaledpos;
begin
    if pdf_link_stack_ptr < 1 then
        pdf_error("ext4", "pdf_link_stack empty, \pdfendlink used without \pdfstartlink?");
    if pdf_link_stack_top.nesting_level <> cur_s then
        pdf_error("ext4", "\pdfendlink ended up in different nesting level than \pdfstartlink");

    {N.B.: test for running link must be done on |link_node| and not |ref_link_node|,
     as |ref_link_node| can be set by |do_link| or |append_link| already}

    if is_running(pdf_width(pdf_link_stack_top.link_node)) then begin
        p := pdf_link_stack_top.ref_link_node;
        if is_shipping_page and matrixused then begin
            matrixrecalculate(cur.h + pdf_link_margin);
            pdf_ann_left(p)   := getllx - pdf_link_margin;
            pdf_ann_top(p)    := cur_page_size.v - getury - pdf_link_margin;
            pdf_ann_right(p)  := geturx + pdf_link_margin;
            pdf_ann_bottom(p) := cur_page_size.v - getlly + pdf_link_margin;
        end
        else begin
            tmp1.h := cur.h; tmp1.v := cur.v;
            tmp2 := synch_p_with_c(tmp1);
            case box_direction(dvi_direction) of
            dir_TL_, dir_BL_: pdf_ann_right(p)  := tmp2.h + pdf_link_margin;
            dir_TR_, dir_BR_: pdf_ann_left(p)   := tmp2.h - pdf_link_margin;
            dir_LT_, dir_RT_: pdf_ann_bottom(p) := tmp2.v - pdf_link_margin;
            dir_LB_, dir_RB_: pdf_ann_top(p)    := tmp2.v + pdf_link_margin;
            endcases;
        end;
    end;
    pop_link_level;
end;

@ For ``running'' annotations we must append a new node when the end of
annotation is in other box than its start. The new created node is identical to
corresponding whatsit node representing the start of annotation,  but its
|info| field is |max_halfword|. We set |info| field just before destroying the
node, in order to use |flush_node_list| to do the job.

@<Declare procedures needed in |pdf_hlist_out|, |pdf_vlist_out|@>=
procedure append_link(parent_box: pointer; x, y: scaled; i: small_number); {append a new
pdf annot to |pdf_link_list|}
var p: pointer;
begin
    pdfassert(type(parent_box) = hlist_node);
    p := copy_node(pdf_link_stack[i].link_node);
    pdf_link_stack[i].ref_link_node := p;
    subtype(p) := pdf_link_data_node; { this node is not a normal link node}
    set_rect_dimens(p, parent_box, x, y,
                    pdf_width(p), pdf_height(p), pdf_depth(p),
                    pdf_link_margin);
    pdf_create_obj(obj_type_others, 0);
    obj_annot_ptr(obj_ptr) := p;
    pdf_append_list(obj_ptr)(pdf_link_list);
end;

@ Threads are handled in similar way as link annotations.

@<Declare procedures needed in |pdf_hlist_out|, |pdf_vlist_out|@>=
procedure append_bead(p: pointer);
var a, b, c, t: integer;
begin
    if not is_shipping_page then
        pdf_error("ext4", "threads cannot be inside an XForm");
    t := get_obj(obj_type_thread, pdf_thread_id(p), pdf_thread_named_id(p));
    b := pdf_new_objnum;
    obj_bead_ptr(b) := pdf_get_mem(pdfmem_bead_size);
    obj_bead_page(b) := pdf_last_page;
    obj_bead_data(b) := p;
    if pdf_thread_attr(p) <> null then
        obj_bead_attr(b) := tokens_to_string(pdf_thread_attr(p))
    else
        obj_bead_attr(b) := 0;
    if obj_thread_first(t) = 0 then begin
        obj_thread_first(t) := b;
        obj_bead_next(b) := b;
        obj_bead_prev(b) := b;
    end
    else begin
        a := obj_thread_first(t);
        c := obj_bead_prev(a);
        obj_bead_prev(b) := c;
        obj_bead_next(b) := a;
        obj_bead_prev(a) := b;
        obj_bead_next(c) := b;
    end;
    pdf_append_list(b)(pdf_bead_list);
end;

procedure do_thread(p, parent_box: pointer; x, y: scaled);
begin
    if doing_leaders then
        return;
    if subtype(p) = pdf_start_thread_node then begin
        pdf_thread_wd := pdf_width(p);
        pdf_thread_ht := pdf_height(p);
        pdf_thread_dp := pdf_depth(p);
        pdf_last_thread_id := pdf_thread_id(p);
        pdf_last_thread_named_id := (pdf_thread_named_id(p) > 0);
        if pdf_last_thread_named_id then
            add_token_ref(pdf_thread_id(p));
        pdf_thread_level := cur_s;
    end;
    set_rect_dimens(p, parent_box, x, y,
                    pdf_width(p), pdf_height(p), pdf_depth(p),
                    pdf_thread_margin);
    append_bead(p);
    last_thread := p;
end;

procedure append_thread(parent_box: pointer; x, y: scaled);
var p: pointer;
begin
    p := new_node(whatsit_node,pdf_thread_data_node);
    pdf_width(p) := pdf_thread_wd;
    pdf_height(p) := pdf_thread_ht;
    pdf_depth(p) := pdf_thread_dp;
    pdf_thread_attr(p) := null;
    pdf_thread_id(p) := pdf_last_thread_id;
    if pdf_last_thread_named_id then begin
        add_token_ref(pdf_thread_id(p));
        pdf_thread_named_id(p) := 1;
    end
    else
        pdf_thread_named_id(p) := 0;
    set_rect_dimens(p, parent_box, x, y,
                    pdf_width(p), pdf_height(p), pdf_depth(p),
                    pdf_thread_margin);
    append_bead(p);
    last_thread := p;
end;

procedure end_thread;
var tmp1, tmp2: scaledpos;
begin
    if pdf_thread_level <> cur_s then
        pdf_error("ext4", "\pdfendthread ended up in different nesting level than \pdfstartthread");
    if is_running(pdf_thread_dp) and (last_thread <> null) then begin
        tmp1.h := cur.h; tmp1.v := cur.v;
        tmp2 := synch_p_with_c(tmp1);
        case box_direction(dvi_direction) of
        dir_TL_, dir_TR_: pdf_ann_bottom(last_thread) := tmp2.v - pdf_thread_margin;
        dir_BL_, dir_BR_: pdf_ann_top(last_thread)    := tmp2.v + pdf_thread_margin;
        dir_LT_, dir_LB_: pdf_ann_right(last_thread)  := tmp2.h + pdf_thread_margin;
        dir_RT_, dir_RB_: pdf_ann_left(last_thread)   := tmp2.h - pdf_thread_margin;
        endcases;
        end;
    if pdf_last_thread_named_id then
        delete_token_ref(pdf_last_thread_id);
    last_thread := null;
end;

function open_subentries(p: pointer): integer;
var k, c: integer;
    l, r: integer;
begin
    k := 0;
    if obj_outline_first(p) <> 0 then begin
        l := obj_outline_first(p);
        repeat
            incr(k);
            c := open_subentries(l);
            if obj_outline_count(l) > 0 then
                k := k + c;
            obj_outline_parent(l) := p;
            r := obj_outline_next(l);
            if r = 0 then
                obj_outline_last(p) := l;
            l := r;
        until l = 0;
    end;
    if obj_outline_count(p) > 0 then
        obj_outline_count(p) := k
    else
        obj_outline_count(p) := -k;
    open_subentries := k;
end;

procedure do_dest(p, parent_box: pointer; x, y: scaled);
var k: integer;
tmp1, tmp2: scaledpos;
begin
    if not is_shipping_page then
        pdf_error("ext4", "destinations cannot be inside an XForm");
    if doing_leaders then
        return;
    k := get_obj(obj_type_dest, pdf_dest_id(p), pdf_dest_named_id(p));
    if obj_dest_ptr(k) <> null then begin
        warn_dest_dup(pdf_dest_id(p), pdf_dest_named_id(p),
                      "ext4", "has been already used, duplicate ignored");
        return;
    end;
    obj_dest_ptr(k) := p;
    pdf_append_list(k)(pdf_dest_list);
    case pdf_dest_type(p) of
    pdf_dest_xyz:
        if matrixused then
            set_rect_dimens(p, parent_box, x, y,
                            pdf_width(p), pdf_height(p), pdf_depth(p),
                            pdf_dest_margin)
        else begin
        tmp1.h := cur.h; tmp1.v := cur.v;
        tmp2 := synch_p_with_c(tmp1);
        pdf_ann_left(p) := tmp2.h;
        pdf_ann_top(p) := tmp2.v;
    end;
    pdf_dest_fith,
    pdf_dest_fitbh:
        if matrixused then
            set_rect_dimens(p, parent_box, x, y,
                            pdf_width(p), pdf_height(p), pdf_depth(p),
                            pdf_dest_margin)
        else begin
        tmp1.h := cur.h; tmp1.v := cur.v;
        tmp2 := synch_p_with_c(tmp1);
        pdf_ann_top(p) := tmp2.v;
        end;
    pdf_dest_fitv,
    pdf_dest_fitbv:
        if matrixused then
            set_rect_dimens(p, parent_box, x, y,
                            pdf_width(p), pdf_height(p), pdf_depth(p),
                            pdf_dest_margin)
        else begin
        tmp1.h := cur.h; tmp1.v := cur.v;
        tmp2 := synch_p_with_c(tmp1);
        pdf_ann_left(p) := tmp2.h;
        end;
    pdf_dest_fit,
    pdf_dest_fitb:
        do_nothing;
    pdf_dest_fitr:
        set_rect_dimens(p, parent_box, x, y,
                        pdf_width(p), pdf_height(p), pdf_depth(p),
                        pdf_dest_margin);
    endcases;
end;

procedure output_form(p: pointer);
begin
    pdf_goto_pagemode;
    pdf_place_form(pos.h, pos.v, obj_info(pdf_xform_objnum(p)));
    if pdf_lookup_list(pdf_xform_list, pdf_xform_objnum(p)) = null then
        pdf_append_list(pdf_xform_objnum(p))(pdf_xform_list);
end;

procedure output_image(idx: integer);
begin
    pdf_goto_pagemode;
    out_image(idx, pos.h, pos.v);
    if pdf_lookup_list(pdf_ximage_list, image_objnum(idx)) = null then
        pdf_append_list(image_objnum(idx))(pdf_ximage_list);
end;

@ @<Output the whatsit node |p| in |pdf_vlist_out|@>=
case subtype(p) of
pdf_literal_node:
    pdf_out_literal(p);
pdf_colorstack_node:
    pdf_out_colorstack(p);
pdf_setmatrix_node:
    pdf_out_setmatrix(p);
pdf_save_node:
    pdf_out_save;
pdf_restore_node:
    pdf_out_restore;
late_lua_node:
    do_late_lua(p);
pdf_refobj_node:
    if not is_obj_scheduled(pdf_obj_objnum(p)) then begin
        pdf_append_list(pdf_obj_objnum(p))(pdf_obj_list);
        set_obj_scheduled(pdf_obj_objnum(p));
    end;
pdf_refxform_node:
    @<Output a Form node in a vlist@>;
pdf_refximage_node:
    @<Output an Image node in a vlist@>;
pdf_annot_node:
    do_annot(p, this_box, left_edge, top_edge + height(this_box));
pdf_start_link_node:
    pdf_error("ext4", "\pdfstartlink ended up in vlist");
pdf_end_link_node:
    pdf_error("ext4", "\pdfendlink ended up in vlist");
pdf_dest_node:
    do_dest(p, this_box, left_edge, top_edge + height(this_box));
pdf_thread_node,
pdf_start_thread_node:
    do_thread(p, this_box, left_edge, top_edge + height(this_box));
pdf_end_thread_node:
    end_thread;
pdf_save_pos_node:
    @<Save current position@>;
special_node:
    pdf_special(p);
othercases out_what(p);
endcases

@ @<Glob...@>=
@!is_shipping_page: boolean; {set to |shipping_page| when |pdf_ship_out| starts}

@ @<Output an Image node in a vlist@>=
begin cur.h:=left_edge;
  synch_pos_with_cur;
  case box_direction(dvi_direction) of
  dir_TL_: begin
    pos_down(pdf_height(p)+pdf_depth(p));
    end;
  dir_TR_: begin
    pos_left(pdf_width(p));
    pos_down(pdf_height(p)+pdf_depth(p));
    end;
  dir_BL_: begin
    end;
  dir_BR_: begin
    pos_left(pdf_width(p));
    end;
  dir_LT_: begin
    pos_down(pdf_width(p));
    end;
  dir_RT_: begin
    pos_left(pdf_height(p)+pdf_depth(p));
    pos_down(pdf_width(p));
    end;
  dir_LB_: begin
    end;
  dir_RB_: begin
    pos_left(pdf_height(p)+pdf_depth(p));
    end;
  othercases
  endcases;
  output_image(pdf_ximage_idx(p));
  cur.v:=cur.v+pdf_height(p)+pdf_depth(p);
end

@ @<Output a Form node in a vlist@>=
begin
  cur.h:=left_edge;
  synch_pos_with_cur;
  case box_direction(dvi_direction) of
  dir_TL_: begin
    pos_down(pdf_height(p)+pdf_depth(p));
    end;
  dir_TR_: begin
    pos_left(pdf_width(p));
    pos_down(pdf_height(p)+pdf_depth(p));
    end;
  othercases
  endcases;
  output_form(p);
  cur.v:=cur.v+pdf_height(p)+pdf_depth(p);
end

@ @<Output the whatsit node |p| in |pdf_hlist_out|@>=
case subtype(p) of
pdf_literal_node:
    pdf_out_literal(p);
pdf_colorstack_node:
    pdf_out_colorstack(p);
pdf_setmatrix_node:
    pdf_out_setmatrix(p);
pdf_save_node:
    pdf_out_save;
pdf_restore_node:
    pdf_out_restore;
late_lua_node:
    do_late_lua(p);
pdf_refobj_node:
    if not is_obj_scheduled(pdf_obj_objnum(p)) then begin
        pdf_append_list(pdf_obj_objnum(p))(pdf_obj_list);
        set_obj_scheduled(pdf_obj_objnum(p));
    end;
pdf_refxform_node:
    @<Output a Form node in a hlist@>;
pdf_refximage_node:
    @<Output an Image node in a hlist@>;
pdf_annot_node:
    do_annot(p, this_box, left_edge, base_line);
pdf_start_link_node:
    do_link(p, this_box, left_edge, base_line);
pdf_end_link_node:
    end_link;
pdf_dest_node:
    do_dest(p, this_box, left_edge, base_line);
pdf_thread_node:
    do_thread(p, this_box, left_edge, base_line);
pdf_start_thread_node:
    pdf_error("ext4", "\pdfstartthread ended up in hlist");
pdf_end_thread_node:
    pdf_error("ext4", "\pdfendthread ended up in hlist");
pdf_save_pos_node:
    @<Save current position@>;
special_node:
    pdf_special(p);
othercases if subtype(p)<>dir_node then out_what(p)
else @<Output a reflection instruction if the direction has changed@>;
endcases

@ @<Output an Image node in a hlist@>=
begin
  cur.v:=base_line;
  synch_pos_with_cur;
  case box_direction(dvi_direction) of
  dir_TL_: begin
    pos_down(pdf_depth(p));
    end;
  dir_TR_: begin
    pos_left(pdf_width(p));
    pos_down(pdf_depth(p));
    end;
  dir_BL_: begin
    pos_down(pdf_height(p));
    end;
  dir_BR_: begin
    pos_left(pdf_width(p));
    pos_down(pdf_height(p));
    end;
  dir_LT_: begin
    pos_left(pdf_height(p));
    pos_down(pdf_width(p));
    end;
  dir_RT_: begin
    pos_left(pdf_depth(p));
    pos_down(pdf_width(p));
    end;
  dir_LB_: begin
    pos_left(pdf_height(p));
    end;
  dir_RB_: begin
    pos_left(pdf_depth(p));
    end;
  othercases
  endcases;
  output_image(pdf_ximage_idx(p));
  edge:=cur.h+pdf_width(p); cur.h:=edge;
end

@ @<Output a Form node in a hlist@>=
begin
  cur.v:=base_line;
  synch_pos_with_cur;
  case box_direction(dvi_direction) of
  dir_TL_: begin
    pos_down(pdf_depth(p));
    end;
  dir_TR_: begin
    pos_down(pdf_depth(p));
    pos_left(pdf_width(p));
    end;
  othercases
  endcases;
  output_form(p);
  edge:=cur.h+pdf_width(p); cur.h:=edge;
end

@* \[53a] The extended features of \eTeX.
The program has two modes of operation:  (1)~In \TeX\ compatibility mode
it fully deserves the name \TeX\ and there are neither extended features
nor additional primitive commands.  There are, however, a few
modifications that would be legitimate in any implementation of \TeX\
such as, e.g., preventing inadequate results of the glue to \.{DVI}
unit conversion during |ship_out|.  (2)~In extended mode there are
additional primitive commands and the extended features of \eTeX\ are
available.

The distinction between these two modes of operation initially takes
place when a `virgin' \.{eINITEX} starts without reading a format file.
Later on the values of all \eTeX\ state variables are inherited when
\.{eVIRTEX} (or \.{eINITEX}) reads a format file.

The code below is designed to work for cases where `$|init|\ldots|tini|$'
is a run-time switch.

@<Enable \eTeX, if requested@>=
@!init if format_ident=" (INITEX)" then
  begin no_new_control_sequence:=false;
  @<Generate all \eTeX\ primitives@>@;
  if buffer[loc]="*" then incr(loc);
  end;
tini@;@/
if not no_new_control_sequence then {just entered extended mode ?}
  no_new_control_sequence:=true@+else

@ The \eTeX\ features available in extended mode are grouped into two
categories:  (1)~Some of them are permanently enabled and have no
semantic effect as long as none of the additional primitives are
executed.  (2)~The remaining \eTeX\ features are optional and can be
individually enabled and disabled.  For each optional feature there is
an \eTeX\ state variable named \.{\\...state}; the feature is enabled,
resp.\ disabled by assigning a positive, resp.\ non-positive value to
that integer.


@d Aleph_version_code=Aleph_int {code for \.{\\Alephversion}}
@d Omega_version_code=Aleph_int+1 {code for \.{\\Omegaversion}}
@d Aleph_minor_version_code=Aleph_int+2 {code for \.{\\Alephminorversion}}
@d Omega_minor_version_code=Aleph_int+3 {code for \.{\\Omegaminorversion}}
@d eTeX_minor_version_code=Aleph_int+4 {code for \.{\\eTeXminorversion}}
@d eTeX_version_code=eTeX_int {code for \.{\\eTeXversion}}
@d Aleph_revision_code=job_name_code+1 {command code for \.{\\Alephrevision}}
@d Omega_revision_code=job_name_code+2 {command code for \.{\\Omegarevision}}
@d eTeX_revision_code=job_name_code+3 {command code for \.{\\eTeXrevision}}
@d font_identifier_code==job_name_code+4 {command code for \.{tex.fontidentifer} (lua)}

@<Generate all \eTeX...@>=
primitive_etex("lastnodetype",last_item,last_node_type_code,0);
@!@:last_node_type_}{\.{\\lastnodetype} primitive@>
primitive_aleph("Alephversion",last_item,Aleph_version_code,0);
@!@:eTeX_version_}{\.{\\Alephversion} primitive@>
primitive_aleph("Omegaversion",last_item,Omega_version_code,0);
@!@:eTeX_version_}{\.{\\Omegaversion} primitive@>
primitive_etex("eTeXversion",last_item,eTeX_version_code,0);
@!@:eTeX_version_}{\.{\\eTeXversion} primitive@>
primitive_aleph("Alephminorversion",last_item,Aleph_minor_version_code,0);
@!@:eTeX_minor_version_}{\.{\\Alephminorversion} primitive@>
primitive_aleph("Omegaminorversion",last_item,Omega_minor_version_code,0);
@!@:eTeX_minor_version_}{\.{\\Omegaminorversion} primitive@>
primitive_etex("eTeXminorversion",last_item,eTeX_minor_version_code,0);
@!@:eTeX_minor_version_}{\.{\\eTeXminorversion} primitive@>
primitive_aleph("Alephrevision",convert,Aleph_revision_code,0);@/
@!@:eTeX_revision_}{\.{\\Alephrevision} primitive@>
primitive_aleph("Omegarevision",convert,Omega_revision_code,0);@/
@!@:eTeX_revision_}{\.{\\Omegarevision} primitive@>
primitive_etex("eTeXrevision",convert,eTeX_revision_code,0);@/
@!@:eTeX_revision_}{\.{\\eTeXrevision} primitive@>

@ @<Cases for fetching an integer value@>=
Aleph_version_code: cur_val:=Aleph_version;
Omega_version_code: cur_val:=Omega_version;
eTeX_version_code: cur_val:=eTeX_version;
Aleph_minor_version_code: cur_val:=Aleph_minor_version;
Omega_minor_version_code: cur_val:=Omega_minor_version;
eTeX_minor_version_code: cur_val:=eTeX_minor_version;

@ @<Cases of `Scan the argument for command |c|'@>=
Aleph_revision_code: do_nothing;
Omega_revision_code: do_nothing;
eTeX_revision_code: do_nothing;

@ @<Cases of `Print the result of command |c|'@>=
Aleph_revision_code: print(Aleph_revision);
Omega_revision_code: print(Omega_revision);
eTeX_revision_code: print(eTeX_revision);

@ First we implement the additional \eTeX\ parameters in the table of
equivalents.

@<Generate all \eTeX...@>=
primitive_etex("everyeof",assign_toks,every_eof_loc,local_base);
@!@:every_eof_}{\.{\\everyeof} primitive@>
primitive_etex("tracingassigns",assign_int,int_base+tracing_assigns_code,int_base);@/
@!@:tracing_assigns_}{\.{\\tracingassigns} primitive@>
primitive_etex("tracinggroups",assign_int,int_base+tracing_groups_code,int_base);@/
@!@:tracing_groups_}{\.{\\tracinggroups} primitive@>
primitive_etex("tracingifs",assign_int,int_base+tracing_ifs_code,int_base);@/
@!@:tracing_ifs_}{\.{\\tracingifs} primitive@>
primitive_etex("tracingscantokens",assign_int,int_base+tracing_scan_tokens_code,int_base);@/
@!@:tracing_scan_tokens_}{\.{\\tracingscantokens} primitive@>
primitive_etex("tracingnesting",assign_int,int_base+tracing_nesting_code,int_base);@/
@!@:tracing_nesting_}{\.{\\tracingnesting} primitive@>
primitive_etex("predisplaydirection", assign_int,int_base+pre_display_direction_code,int_base);@/
@!@:pre_display_direction_}{\.{\\predisplaydirection} primitive@>
primitive_etex("lastlinefit",assign_int,int_base+last_line_fit_code,int_base);@/
@!@:last_line_fit_}{\.{\\lastlinefit} primitive@>
primitive_etex("savingvdiscards",assign_int,int_base+saving_vdiscards_code,int_base);@/
@!@:saving_vdiscards_}{\.{\\savingvdiscards} primitive@>
primitive_etex("savinghyphcodes",assign_int,int_base+saving_hyph_codes_code,int_base);@/
@!@:saving_hyph_codes_}{\.{\\savinghyphcodes} primitive@>
primitive_luatex("suppressfontnotfounderror",assign_int,int_base+suppress_fontnotfound_error_code,int_base);@/
@!@:suppress_fontnotfound_error_code_}{\.{\\suppressfontnotfounderror} primitive@>
primitive_luatex("suppresslongerror",assign_int,int_base+suppress_long_error_code,int_base);@/
@!@:suppress_long_error_code_}{\.{\\suppresslongerror} primitive@>
primitive_luatex("suppressifcsnameerror",assign_int,int_base+suppress_ifcsname_error_code,int_base);@/
@!@:suppress_ifcsname_error_code_}{\.{\\suppressifcsnameerror} primitive@>
primitive_luatex("suppressoutererror",assign_int,int_base+suppress_outer_error_code,int_base);@/
@!@:suppress_outer_error_code_}{\.{\\suppressoutererror} primitive@>
primitive_luatex("synctex",assign_int,int_base+synctex_code,int_base);@/
@!@:synctex_}{\.{\\synctex} primitive@>

@ @d every_eof==equiv(every_eof_loc)

@ @<Cases for |print_param|@>=
tracing_assigns_code:print_esc("tracingassigns");
tracing_groups_code:print_esc("tracinggroups");
tracing_ifs_code:print_esc("tracingifs");
tracing_scan_tokens_code:print_esc("tracingscantokens");
tracing_nesting_code:print_esc("tracingnesting");
pre_display_direction_code:print_esc("predisplaydirection");
last_line_fit_code:print_esc("lastlinefit");
saving_vdiscards_code:print_esc("savingvdiscards");
saving_hyph_codes_code:print_esc("savinghyphcodes");
suppress_fontnotfound_error_code:print_esc("suppressfontnotfounderror");
suppress_long_error_code:print_esc("suppresslongerror");
suppress_outer_error_code:print_esc("suppressoutererror");
synctex_code:print_esc("synctex");

@ In order to handle \.{\\everyeof} we need an array |eof_seen| of
boolean variables.

@<Glob...@>=
@!eof_seen : array[1..max_in_open] of boolean; {has eof been seen?}

@ The |print_group| procedure prints the current level of grouping and
the name corresponding to |cur_group|.

@<Declare \eTeX\ procedures for tr...@>=
procedure print_group(@!e:boolean);
label exit;
begin case cur_group of
  bottom_level: begin print("bottom level"); return;
    end;
  simple_group,semi_simple_group:
    begin if cur_group=semi_simple_group then print("semi ");
    print("simple");
    end;
  hbox_group,adjusted_hbox_group:
    begin if cur_group=adjusted_hbox_group then print("adjusted ");
    print("hbox");
    end;
  vbox_group: print("vbox");
  vtop_group: print("vtop");
  align_group,no_align_group:
    begin if cur_group=no_align_group then print("no ");
    print("align");
    end;
  output_group: print("output");
  disc_group: print("disc");
  insert_group: print("insert");
  vcenter_group: print("vcenter");
  math_group,math_choice_group,math_shift_group,math_left_group:
    begin print("math");
    if cur_group=math_choice_group then print(" choice")
    else if cur_group=math_shift_group then print(" shift")
    else if cur_group=math_left_group then print(" left");
    end;
  end; {there are no other cases}
print(" group (level "); print_int(qo(cur_level)); print_char(")");
if saved(-1)<>0 then
  begin if e then print(" entered at line ") else print(" at line ");
  print_int(saved(-1));
  end;
exit:end;

@ The |group_trace| procedure is called when a new level of grouping
begins (|e=false|) or ends (|e=true|) with |saved(-1)| containing the
line number.

@<Declare \eTeX\ procedures for tr...@>=
@!stat procedure group_trace(@!e:boolean);
begin begin_diagnostic; print_char("{");
if e then print("leaving ") else print("entering ");
print_group(e); print_char("}"); end_diagnostic(false);
end;
tats

@ The \.{\\currentgrouplevel} and \.{\\currentgrouptype} commands return
the current level of grouping and the type of the current group
respectively.

@d current_group_level_code=eTeX_int+1 {code for \.{\\currentgrouplevel}}
@d current_group_type_code=eTeX_int+2 {code for \.{\\currentgrouptype}}

@<Generate all \eTeX...@>=
primitive_etex("currentgrouplevel",last_item,current_group_level_code,0);
@!@:current_group_level_}{\.{\\currentgrouplevel} primitive@>
primitive_etex("currentgrouptype",last_item,current_group_type_code,0);
@!@:current_group_type_}{\.{\\currentgrouptype} primitive@>

@ @<Cases for fetching an integer value@>=
current_group_level_code: cur_val:=cur_level-level_one;
current_group_type_code: cur_val:=cur_group;

@ The \.{\\currentiflevel}, \.{\\currentiftype}, and
\.{\\currentifbranch} commands return the current level of conditionals
and the type and branch of the current conditional.

@d current_if_level_code=eTeX_int+3 {code for \.{\\currentiflevel}}
@d current_if_type_code=eTeX_int+4 {code for \.{\\currentiftype}}
@d current_if_branch_code=eTeX_int+5 {code for \.{\\currentifbranch}}

@<Generate all \eTeX...@>=
primitive_etex("currentiflevel",last_item,current_if_level_code,0);
@!@:current_if_level_}{\.{\\currentiflevel} primitive@>
primitive_etex("currentiftype",last_item,current_if_type_code,0);
@!@:current_if_type_}{\.{\\currentiftype} primitive@>
primitive_etex("currentifbranch",last_item,current_if_branch_code,0);
@!@:current_if_branch_}{\.{\\currentifbranch} primitive@>

@ @<Cases for fetching an integer value@>=
current_if_level_code: begin q:=cond_ptr; cur_val:=0;
  while q<>null do
    begin incr(cur_val); q:=vlink(q);
    end;
  end;
current_if_type_code: if cond_ptr=null then cur_val:=0
  else if cur_if<unless_code then cur_val:=cur_if+1
  else cur_val:=-(cur_if-unless_code+1);
current_if_branch_code:
  if (if_limit=or_code)or(if_limit=else_code) then cur_val:=1
  else if if_limit=fi_code then cur_val:=-1
  else cur_val:=0;

@ The \.{\\fontcharwd}, \.{\\fontcharht}, \.{\\fontchardp}, and
\.{\\fontcharic} commands return information about a character in a
font.

@d font_char_wd_code=eTeX_dim {code for \.{\\fontcharwd}}
@d font_char_ht_code=eTeX_dim+1 {code for \.{\\fontcharht}}
@d font_char_dp_code=eTeX_dim+2 {code for \.{\\fontchardp}}
@d font_char_ic_code=eTeX_dim+3 {code for \.{\\fontcharic}}

@<Generate all \eTeX...@>=
primitive_omega("charwd",last_item,font_char_wd_code,0);
primitive_etex("fontcharwd",last_item,font_char_wd_code,0);
@!@:font_char_wd_}{\.{\\fontcharwd} primitive@>
primitive_omega("charht",last_item,font_char_ht_code,0);
primitive_etex("fontcharht",last_item,font_char_ht_code,0);
@!@:font_char_ht_}{\.{\\fontcharht} primitive@>
primitive_omega("chardp",last_item,font_char_dp_code,0);
primitive_etex("fontchardp",last_item,font_char_dp_code,0);
@!@:font_char_dp_}{\.{\\fontchardp} primitive@>
primitive_omega("charit",last_item,font_char_ic_code,0);
primitive_etex("fontcharic",last_item,font_char_ic_code,0);
@!@:font_char_ic_}{\.{\\fontcharic} primitive@>

@ @<Cases for fetching a dimension value@>=
font_char_wd_code,
font_char_ht_code,
font_char_dp_code,
font_char_ic_code: begin scan_font_ident; q:=cur_val; scan_char_num;
  if char_exists(q,cur_val) then
    begin
    case m of
    font_char_wd_code: cur_val:=char_width(q,cur_val);
    font_char_ht_code: cur_val:=char_height(q,cur_val);
    font_char_dp_code: cur_val:=char_depth(q,cur_val);
    font_char_ic_code: cur_val:=char_italic(q,cur_val);
    end; {there are no other cases}
    end
  else cur_val:=0;
  end;

@ The \.{\\parshapedimen}, \.{\\parshapeindent}, and \.{\\parshapelength}
commands return the indent and length parameters of the current
\.{\\parshape} specification.

@d par_shape_length_code=eTeX_dim+4 {code for \.{\\parshapelength}}
@d par_shape_indent_code=eTeX_dim+5 {code for \.{\\parshapeindent}}
@d par_shape_dimen_code=eTeX_dim+6 {code for \.{\\parshapedimen}}

@<Generate all \eTeX...@>=
primitive_etex("parshapelength",last_item,par_shape_length_code,0);
@!@:par_shape_length_}{\.{\\parshapelength} primitive@>
primitive_etex("parshapeindent",last_item,par_shape_indent_code,0);
@!@:par_shape_indent_}{\.{\\parshapeindent} primitive@>
primitive_etex("parshapedimen",last_item,par_shape_dimen_code,0);
@!@:par_shape_dimen_}{\.{\\parshapedimen} primitive@>

@ @<Cases for fetching a dimension value@>=
par_shape_length_code,
par_shape_indent_code,
par_shape_dimen_code: begin q:=cur_chr-par_shape_length_code; scan_int;
  if (par_shape_ptr=null)or(cur_val<=0) then cur_val:=0
  else  begin if q=2 then
      begin q:=cur_val mod 2; cur_val:=(cur_val+q)div 2;
      end;
    if cur_val>vinfo(par_shape_ptr+1) then cur_val:=vinfo(par_shape_ptr+1);
    cur_val:=vmem(par_shape_ptr+2*cur_val-q+1).sc;
    end;
  cur_val_level:=dimen_val;
  end;

@ The \.{\\showgroups} command displays all currently active grouping
levels.

@d show_groups=4 { \.{\\showgroups} }

@<Generate all \eTeX...@>=
primitive_etex("showgroups",xray,show_groups,0);
@!@:show_groups_}{\.{\\showgroups} primitive@>

@ @<Cases for |show_whatever|@>=
show_groups: begin begin_diagnostic; show_save_groups;
  end;

@ @<Types...@>=
@!save_pointer=0..save_size; {index into |save_stack|}

@ The modifications of \TeX\ required for the display produced by the
|show_save_groups| procedure were first discussed by Donald~E. Knuth in
{\sl TUGboat\/} {\bf 11}, 165--170 and 499--511, 1990.
@^Knuth, Donald Ervin@>

In order to understand a group type we also have to know its mode.
Since unrestricted horizontal modes are not associated with grouping,
they are skipped when traversing the semantic nest.

@<Declare \eTeX\ procedures for use...@>=
procedure show_save_groups;
label found1,found2,found,done;
var p:0..nest_size; {index into |nest|}
@!m:-mmode..mmode; {mode}
@!v:save_pointer; {saved value of |save_ptr|}
@!l:quarterword; {saved value of |cur_level|}
@!c:group_code; {saved value of |cur_group|}
@!a:-1..1; {to keep track of alignments}
@!i:integer;
@!j:quarterword;
@!s:str_number;
begin p:=nest_ptr; nest[p]:=cur_list; {put the top level into the array}
v:=save_ptr; l:=cur_level; c:=cur_group;
save_ptr:=cur_boundary; decr(cur_level);@/
a:=1; s:="";
print_nl(""); print_ln;
loop@+begin print_nl("### "); print_group(true);
  if cur_group=bottom_level then goto done;
  repeat m:=nest[p].mode_field;
  if p>0 then decr(p) else m:=vmode;
  until m<>hmode;
  print(" (");
  case cur_group of
    simple_group: begin incr(p); goto found2;
      end;
    hbox_group,adjusted_hbox_group: s:="hbox";
    vbox_group: s:="vbox";
    vtop_group: s:="vtop";
    align_group: if a=0 then
        begin if m=-vmode then s:="halign" else s:="valign";
        a:=1; goto found1;
        end
      else  begin if a=1 then print("align entry") else print_esc("cr");
        if p>=a then p:=p-a;
        a:=0; goto found;
        end;
    no_align_group:
      begin incr(p); a:=-1; print_esc("noalign"); goto found2;
      end;
    output_group:
      begin print_esc("output"); goto found;
      end;
    math_group: goto found2;
    disc_group,math_choice_group:
      begin if cur_group=disc_group then print_esc("discretionary")
      else print_esc("mathchoice");
      for i:=1 to 3 do if i<=saved(-2) then print("{}");
      goto found2;
      end;
    insert_group:
      begin if saved(-2)=output_box then print_esc("vadjust")
      else  begin print_esc("insert"); print_int(saved(-2));
        end;
      goto found2;
      end;
    vcenter_group: begin s:="vcenter"; goto found1;
      end;
    semi_simple_group: begin incr(p); print_esc("begingroup"); goto found;
      end;
    math_shift_group:
      begin if m=mmode then print_char("$")
      else if nest[p].mode_field=mmode then
        begin print_cmd_chr(eq_no,saved(-2)); goto found;
        end;
      print_char("$"); goto found;
      end;
    math_left_group:
      begin if subtype(nest[p+1].eTeX_aux_field)=left_noad_side then print_esc("left")
      else print_esc("middle");
      goto found;
      end;
    end; {there are no other cases}
  @<Show the box context@>;
  found1: print_esc(s); @<Show the box packaging info@>;
  found2: print_char("{");
  found: print_char(")"); decr(cur_level);
  cur_group:=save_level(save_ptr); save_ptr:=save_index(save_ptr)
  end;
done: save_ptr:=v; cur_level:=l; cur_group:=c;
end;

@ @<Show the box packaging info@>=
if saved(-2)<>0 then
  begin print_char(" ");
  if saved(-3)=exactly then print("to") else print("spread");
  print_scaled(saved(-2)); print("pt");
  end

@ @<Show the box context@>=
i:=saved(-4);
if i<>0 then begin
  if i<box_flag then
    begin if abs(nest[p].mode_field)=vmode then j:=hmove else j:=vmove;
    if i>0 then print_cmd_chr(j,0) else print_cmd_chr(j,1);
    print_scaled(abs(i)); print("pt");
    end
  else if i<ship_out_flag then
    begin if i>=global_box_flag then
      begin print_esc("global"); i:=i-(global_box_flag-box_flag);
      end;
    print_esc("setbox"); print_int(i-box_flag); print_char("=");
    end
  else print_cmd_chr(leader_ship,i-(leader_flag-a_leaders));
  end

@ The |scan_general_text| procedure is much like |scan_toks(false,false)|,
but will be invoked via |expand|, i.e., recursively.
@^recursion@>

@<Declare \eTeX\ procedures for sc...@>=
procedure@?scan_general_text; forward;@t\2@>

@ The token list (balanced text) created by |scan_general_text| begins
at |link(temp_token_head)| and ends at |cur_val|.  (If |cur_val=temp_token_head|,
the list is empty.)

@<Declare \eTeX\ procedures for tok...@>=
procedure scan_general_text;
label found;
var s:normal..absorbing; {to save |scanner_status|}
@!w:pointer; {to save |warning_index|}
@!d:pointer; {to save |def_ref|}
@!p:pointer; {tail of the token list being built}
@!q:pointer; {new node being added to the token list via |store_new_token|}
@!unbalance:halfword; {number of unmatched left braces}
begin s:=scanner_status; w:=warning_index; d:=def_ref;
scanner_status:=absorbing; warning_index:=cur_cs;
p:=get_avail; def_ref:=p; token_ref_count(def_ref):=0; p:=def_ref;
scan_left_brace; {remove the compulsory left brace}
unbalance:=1;
loop@+  begin get_token;
  if cur_tok<right_brace_limit then begin
    if cur_cmd<right_brace then incr(unbalance)
    else  begin decr(unbalance);
      if unbalance=0 then goto found;
      end;
    end;
  store_new_token(cur_tok);
  end;
found: q:=link(def_ref); free_avail(def_ref); {discard reference count}
if q=null then cur_val:=temp_token_head @+ else cur_val:=p;
link(temp_token_head):=q;
scanner_status:=s; warning_index:=w; def_ref:=d;
end;

@ The \.{\\showtokens} command displays a token list.

@d show_tokens=5 { \.{\\showtokens} , must be odd! }

@<Generate all \eTeX...@>=
primitive_etex("showtokens",xray,show_tokens,0);
@!@:show_tokens_}{\.{\\showtokens} primitive@>

@ The \.{\\unexpanded} primitive prevents expansion of tokens much as
the result from \.{\\the} applied to a token variable.  The
\.{\\detokenize} primitive converts a token list into a list of
character tokens much as if the token list were written to a file.  We
use the fact that the command modifiers for \.{\\unexpanded} and
\.{\\detokenize} are odd whereas those for \.{\\the} and \.{\\showthe}
are even.

@<Generate all \eTeX...@>=
primitive_etex("unexpanded",the,1,0);@/
@!@:unexpanded_}{\.{\\unexpanded} primitive@>
primitive_etex("detokenize",the,show_tokens,0);@/
@!@:detokenize_}{\.{\\detokenize} primitive@>

@ @<Handle \.{\\unexpanded} or \.{\\detokenize} and |return|@>=
if odd(cur_chr) then
  begin c:=cur_chr; scan_general_text;
  if c=1 then the_toks:=cur_val
  else begin old_setting:=selector; selector:=new_string; b:=pool_ptr;
    p:=get_avail; link(p):=link(temp_token_head);
    token_show(p); flush_list(p);
    selector:=old_setting; the_toks:=str_toks(b);
    end;
  return;
  end

@ The \.{\\showifs} command displays all currently active conditionals.

@d show_ifs=6 { \.{\\showifs} }

@<Generate all \eTeX...@>=
primitive_etex("showifs",xray,show_ifs,0);
@!@:show_ifs_}{\.{\\showifs} primitive@>

@
@d print_if_line(#)==if #<>0 then
  begin print(" entered on line "); print_int(#);
  end

@<Cases for |show_whatever|@>=
show_ifs: begin begin_diagnostic; print_nl(""); print_ln;
  if cond_ptr=null then
    begin print_nl("### "); print("no active conditionals");
    end
  else  begin p:=cond_ptr; n:=0;
    repeat incr(n); p:=vlink(p);@+until p=null;
    p:=cond_ptr; t:=cur_if; l:=if_line; m:=if_limit;
    repeat print_nl("### level "); print_int(n); print(": ");
    print_cmd_chr(if_test,t);
    if m=fi_code then print_esc("else");
    print_if_line(l);
    decr(n); t:=if_limit_subtype(p); l:=if_line_field(p); m:=if_limit_type(p); p:=vlink(p);
    until p=null;
    end;
  end;

@ The \.{\\interactionmode} primitive allows to query and set the
interaction mode.

@<Generate all \eTeX...@>=
primitive_etex("interactionmode",set_page_int,2,0);
@!@:interaction_mode_}{\.{\\interactionmode} primitive@>

@ @<Cases for `Fetch the |dead_cycles| or the |insert_penalties|'@>=
else if m=2 then cur_val:=interaction

@ @<Declare \eTeX\ procedures for use...@>=
procedure@?new_interaction; forward;@t\2@>

@ @<Cases for |alter_integer|@>=
else if c=2 then
  begin if (cur_val<batch_mode)or(cur_val>error_stop_mode) then
    begin print_err("Bad interaction mode");
@.Bad interaction mode@>
    help2("Modes are 0=batch, 1=nonstop, 2=scroll, and")@/
    ("3=errorstop. Proceed, and I'll ignore this case.");
    int_error(cur_val);
    end
  else  begin cur_chr:=cur_val; new_interaction;
    end;
  end

@ The |scan_tokens| feature of \eTeX\ defines the \.{\\scantokens}
primitive.

@<Generate all \eTeX...@>=
primitive_etex("scantokens",input,2,0);
@!@:scan_tokens_}{\.{\\scantokens} primitive@>
primitive_luatex("scantextokens",input,3,0);
@!@:scan_tex_tokens_}{\.{\\scantextokens} primitive@>

@ @<Cases for |input|@>=
else if cur_chr=2 then pseudo_start
else if cur_chr=3 then begin pseudo_start; name := 19; end

@ The global variable |pseudo_files| is used to maintain a stack of
pseudo files.  The |pseudo_lines| field of each pseudo file points to
a linked list of variable size nodes representing lines not yet
processed: the |subtype| field contains the size of this node,
all the following words contain ASCII codes.

@<Glob...@>=
@!pseudo_files:pointer; {stack of pseudo files}

@ @<Set init...@>=
pseudo_files:=null;

@ The |pseudo_start| procedure initiates reading from a pseudo file.

@<Declare \eTeX\ procedures for ex...@>=
procedure@?pseudo_start; forward;@t\2@>

@ @<Declare \eTeX\ procedures for tok...@>=
procedure pseudo_start;
var old_setting:0..max_selector; {holds |selector| setting}
@!s:str_number; {string to be converted into a pseudo file}
@!p:pointer; {for list construction}
begin scan_general_text;
old_setting:=selector; selector:=new_string;
token_show(temp_token_head); selector:=old_setting;
flush_list(link(temp_token_head));
str_room(1); s:=make_string;
@<Convert string |s| into a new pseudo file@>;
flush_string;
@<Initiate input from new pseudo file@>;
end;

procedure pseudo_from_string;
var @!s:str_number; {string to be converted into a pseudo file}
@!p:pointer; {for list construction}
begin
s:=make_string;
@<Convert string |s| into a new pseudo file@>;
flush_string;
@<Initiate input from new pseudo file@>;
end;

procedure lua_string_start;
begin
begin_file_reading; {set up |cur_file| and new level of input}
line:=0; limit:=start; loc:=limit+1; {force line read}
name:=21; luacstring_start(index);
end;

@ @<Convert string |s| into a new pseudo file@>=
str_pool[pool_ptr]:=si(" ");
p:=string_to_pseudo(str_start_macro(s),pool_ptr,new_line_char);
vlink(p):=pseudo_files; pseudo_files:=p

@ @<Initiate input from new pseudo file@>=
begin_file_reading; {set up |cur_file| and new level of input}
line:=0; limit:=start; loc:=limit+1; {force line read}
if tracing_scan_tokens>0 then
  begin if term_offset>max_print_line-3 then print_ln
  else if (term_offset>0)or(file_offset>0) then print_char(" ");
  name:=20; print("( "); incr(open_parens); update_terminal;
  end
else begin
  name:=18;
  @<Prepare pseudo file {\sl Sync\TeX} information@>;
end

@ Here we read a line from the current pseudo file into |buffer|.

@d pseudo_lines(#)==vlink(#+1)

@<Declare \eTeX\ procedures for tr...@>=
function pseudo_input: boolean; {inputs the next line or returns |false|}
var p:pointer; {current line from pseudo file}
@!sz:integer; {size of node |p|}
@!w:four_quarters; {four ASCII codes}
@!r:pointer; {loop index}
begin last:=first; {cf.\ Matthew 19\thinspace:\thinspace30}
p:=pseudo_lines(pseudo_files);
if p=null then begin pseudo_input:=false; end
else  begin pseudo_lines(pseudo_files):=vlink(p); sz:=subtype(p);
  if 4*sz-3>=buf_size-last then
     check_buffer_overflow(last+4*sz);
  last:=first;
  for r:=p+1 to p+sz-1 do
    begin w:=vmem(r).qqqq;
    buffer[last]:=w.b0; buffer[last+1]:=w.b1;
    buffer[last+2]:=w.b2; buffer[last+3]:=w.b3;
    last:=last+4;
    end;
  if last>=max_buf_stack then max_buf_stack:=last+1;
  while (last>first)and(buffer[last-1]=" ") do decr(last);
  flush_node(p);
  pseudo_input:=true;
  end;
end;

@ When we are done with a pseudo file we `close' it.

@<Declare \eTeX\ procedures for tr...@>=
procedure pseudo_close; {close the top level pseudo file}
var p: pointer;
begin p:=vlink(pseudo_files);
flush_node(pseudo_files);
pseudo_files:=p;
end;

@ @<Close the pseudo files@>=
while pseudo_files<>null do pseudo_close; {flush pseudo files}

@ @<Generate all \eTeX...@>=
primitive_etex("readline",read_to_cs,1,0);@/
@!@:read_line_}{\.{\\readline} primitive@>

@ @<Handle \.{\\readline} and |goto done|@>=
if j=1 then
  begin while loc<=limit do {current line not yet finished}
    begin cur_chr:=buffer[loc]; incr(loc);
    if cur_chr=" " then cur_tok:=space_token
    @+else cur_tok:=cur_chr+other_token;
    store_new_token(cur_tok);
    end;
  goto done;
  end

@ Here we define the additional conditionals of \eTeX\ as well as the
\.{\\unless} prefix.

@d if_def_code=17 { `\.{\\ifdefined}' }
@d if_cs_code=18 { `\.{\\ifcsname}' }
@d if_font_char_code=19 { `\.{\\iffontchar}' }
@d if_in_csname_code=20 { `\.{\\ifincsname}' }
@d if_abs_num_code=22 { `\.{\\ifabsnum}' } { 21 = |if_primitive|}
@d if_abs_dim_code=23 { `\.{\\ifabsdim}' }

@<Generate all \eTeX...@>=
primitive_etex("unless",expand_after,1,0);@/
@!@:unless_}{\.{\\unless} primitive@>
primitive_etex("ifdefined",if_test,if_def_code,0);
@!@:if_defined_}{\.{\\ifdefined} primitive@>
primitive_etex("ifcsname",if_test,if_cs_code,0);
@!@:if_cs_name_}{\.{\\ifcsname} primitive@>
primitive_etex("iffontchar",if_test,if_font_char_code,0);
@!@:if_font_char_}{\.{\\iffontchar} primitive@>
primitive_pdftex("ifincsname",if_test,if_in_csname_code,0);
@!@:if_in_csname_}{\.{\\ifincsname} primitive@>
primitive_luatex("ifabsnum",if_test,if_abs_num_code,0);
@!@:if_abs_num_}{\.{\\ifabsnum} primitive@>
primitive_luatex("ifabsdim",if_test,if_abs_dim_code,0);
@!@:if_abs_dim_}{\.{\\ifabsdim} primitive@>
primitive_pdftex("ifpdfabsnum",if_test,if_abs_num_code,0);
@!@:if_abs_num_}{\.{\\ifpdfabsnum} primitive@>
primitive_pdftex("ifpdfabsdim",if_test,if_abs_dim_code,0);
@!@:if_abs_dim_}{\.{\\ifpdfabsdim} primitive@>

@ The result of a boolean condition is reversed when the conditional is
preceded by \.{\\unless}.

@<Negate a boolean conditional and |goto reswitch|@>=
begin get_token;
if (cur_cmd=if_test)and(cur_chr<>if_case_code) then
  begin cur_chr:=cur_chr+unless_code; goto reswitch;
  end;
print_err("You can't use `"); print_esc("unless"); print("' before `");
@.You can't use \\unless...@>
print_cmd_chr(cur_cmd,cur_chr); print_char("'");
help1("Continue, and I'll forget that it ever happened.");
back_error;
end

@ The conditional \.{\\ifdefined} tests if a control sequence is
defined.

We need to reset |scanner_status|, since \.{\\outer} control sequences
are allowed, but we might be scanning a macro definition or preamble.

@<Cases for |conditional|@>=
if_def_code:begin save_scanner_status:=scanner_status;
  scanner_status:=normal;
  get_filtered_next; b:=(cur_cmd<>undefined_cs);
  scanner_status:=save_scanner_status;
  end;

@ The conditional \.{\\ifcsname} is equivalent to \.{\{\\expandafter}
\.{\}\\expandafter} \.{\\ifdefined} \.{\\csname}, except that no new
control sequence will be entered into the hash table (once all tokens
preceding the mandatory \.{\\endcsname} have been expanded).

@<Cases for |conditional|@>=
if_cs_code:begin n:=get_avail; p:=n; {head of the list of characters}
  b:=false;
  repeat get_x_token;
  if cur_cs=0 then store_new_token(cur_tok);
  until cur_cs<>0;
  if cur_cmd<>end_cs_name then begin
    if suppress_ifcsname_error then begin
      repeat get_x_token;
      until cur_cmd=end_cs_name;
      end
    else begin
      @<Complain about missing \.{\\endcsname}@>;
      @<Look up the characters of list |n| in the hash table, and set |cur_cs|@>;
      b:=(eq_type(cur_cs)<>undefined_cs);
      end;
    end
  else begin
    @<Look up the characters of list |n| in the hash table, and set |cur_cs|@>;
    b:=(eq_type(cur_cs)<>undefined_cs);
    end;
  flush_list(n);
  end;

@ @<Look up the characters of list |n| in the hash table...@>=
m:=first; p:=link(n);
while p<>null do
  begin if m>=max_buf_stack then
    begin max_buf_stack:=m+4;
    if max_buf_stack=buf_size then
      check_buffer_overflow(max_buf_stack);
@:TeX capacity exceeded buffer size}{\quad buffer size@>
    end;
  s := info(p) mod string_offset;
  if s <= @"7F then begin
    buffer[m]:=s; incr(m);
    end
  else if s<=@"7FF then begin
    buffer[m]:=@"C0 + s div @"40; incr(m);
    buffer[m]:=@"80 + s mod @"40; incr(m);
    end
  else if s<=@"FFFF then begin
    buffer[m]:=@"E0 + s div @"1000; incr(m);
    buffer[m]:=@"80 + (s mod @"1000) div @"40; incr(m);
    buffer[m]:=@"80 + (s mod @"1000) mod @"40; incr(m);
    end
  else begin
    buffer[m]:=@"F0 + s div @"40000;  incr(m);
    buffer[m]:=@"80 + (s mod @"40000) div @"1000;  incr(m);
    buffer[m]:=@"80 + ((s mod @"40000) mod @"1000) div @"40;  incr(m);
    buffer[m]:=@"80 + ((s mod @"40000) mod @"1000) mod @"40;  incr(m);
    end;
  p:=link(p);
  end;
if m>first then
  cur_cs:=id_lookup(first,m-first) {|no_new_control_sequence| is |true|}
else if m=first then cur_cs:=null_cs {the list is empty}

@ The conditional \.{\\iffontchar} tests the existence of a character in
a font.

@<Cases for |conditional|@>=
if_in_csname_code: b := is_in_csname;
if_abs_dim_code, if_abs_num_code: begin
  if this_if=if_abs_num_code then scan_int@+else scan_normal_dimen;
  n:=cur_val;
  if n < 0 then negate(n);
  @<Get the next non-blank non-call...@>;
  if (cur_tok>=other_token+"<")and(cur_tok<=other_token+">") then
    r:=cur_tok-other_token
  else  begin print_err("Missing = inserted for ");
  @.Missing = inserted@>
    print_cmd_chr(if_test,this_if);
    help1("I was expecting to see `<', `=', or `>'. Didn't.");
    back_error; r:="=";
    end;
  if this_if=if_abs_num_code then scan_int@+else scan_normal_dimen;
  if cur_val < 0 then negate(cur_val);
  case r of
  "<": b:=(n<cur_val);
  "=": b:=(n=cur_val);
  ">": b:=(n>cur_val);
  end;
  end;
if_font_char_code:begin scan_font_ident; n:=cur_val; scan_char_num;
  b:=char_exists(n,cur_val);
  end;

@ The |protected| feature of \eTeX\ defines the \.{\\protected} prefix
command for macro definitions.  Such macros are protected against
expansions when lists of expanded tokens are built, e.g., for \.{\\edef}
or during \.{\\write}.

@<Generate all \eTeX...@>=
primitive_etex("protected",prefix,8,0);
@!@:protected_}{\.{\\protected} primitive@>

@ The |get_x_or_protected| procedure is like |get_x_token| except that
protected macros are not expanded.

@<Declare \eTeX\ procedures for sc...@>=
procedure get_x_or_protected; {sets |cur_cmd|, |cur_chr|, |cur_tok|,
  and expands non-protected macros}
label exit;
begin loop@+begin get_token;
  if cur_cmd<=max_command then return;
  if (cur_cmd>=call)and(cur_cmd<end_template) then
    if info(link(cur_chr))=protected_token then return;
  expand;
  end;
exit:end;

@ A group entered (or a conditional started) in one file may end in a
different file.  Such slight anomalies, although perfectly legitimate,
may cause errors that are difficult to locate.  In order to be able to
give a warning message when such anomalies occur, \eTeX\ uses the
|grp_stack| and |if_stack| arrays to record the initial |cur_boundary|
and |cond_ptr| values for each input file.

@<Glob...@>=
@!grp_stack : array[0..max_in_open] of save_pointer; {initial |cur_boundary|}
@!if_stack : array[0..max_in_open] of pointer; {initial |cond_ptr|}

@ When a group ends that was apparently entered in a different input
file, the |group_warning| procedure is invoked in order to update the
|grp_stack|.  If moreover \.{\\tracingnesting} is positive we want to
give a warning message.  The situation is, however, somewhat complicated
by two facts:  (1)~There may be |grp_stack| elements without a
corresponding \.{\\input} file or \.{\\scantokens} pseudo file (e.g.,
error insertions from the terminal); and (2)~the relevant information is
recorded in the |name_field| of the |input_stack| only loosely
synchronized with the |in_open| variable indexing |grp_stack|.

@<Declare \eTeX\ procedures for tr...@>=
procedure group_warning;
var i:0..max_in_open; {index into |grp_stack|}
@!w:boolean; {do we need a warning?}
begin base_ptr:=input_ptr; input_stack[base_ptr]:=cur_input;
  {store current state}
i:=in_open; w:=false;
while (grp_stack[i]=cur_boundary)and(i>0) do
  begin @<Set variable |w| to indicate if this case should be reported@>;
  grp_stack[i]:=save_index(save_ptr); decr(i);
  end;
if w then
  begin print_nl("Warning: end of "); print_group(true);
@.Warning: end of...@>
  print(" of a different file"); print_ln;
  if tracing_nesting>1 then show_context;
  if history=spotless then history:=warning_issued;
  end;
end;

@ This code scans the input stack in order to determine the type of the
current input file.

@<Set variable |w| to...@>=
if tracing_nesting>0 then
  begin while (input_stack[base_ptr].state_field=token_list)or@|
    (input_stack[base_ptr].index_field>i) do decr(base_ptr);
  if input_stack[base_ptr].name_field>17 then w:=true;
  end

@ When a conditional ends that was apparently started in a different
input file, the |if_warning| procedure is invoked in order to update the
|if_stack|.  If moreover \.{\\tracingnesting} is positive we want to
give a warning message (with the same complications as above).

@<Declare \eTeX\ procedures for tr...@>=
procedure if_warning;
var i:0..max_in_open; {index into |if_stack|}
@!w:boolean; {do we need a warning?}
begin base_ptr:=input_ptr; input_stack[base_ptr]:=cur_input;
  {store current state}
i:=in_open; w:=false;
while if_stack[i]=cond_ptr do
  begin @<Set variable |w| to...@>;
  if_stack[i]:=vlink(cond_ptr); decr(i);
  end;
if w then
  begin print_nl("Warning: end of "); print_cmd_chr(if_test,cur_if);
@.Warning: end of...@>
  print_if_line(if_line); print(" of a different file"); print_ln;
  if tracing_nesting>1 then show_context;
  if history=spotless then history:=warning_issued;
  end;
end;

@ Conversely, the |file_warning| procedure is invoked when a file ends
and some groups entered or conditionals started while reading from that
file are still incomplete.

@<Declare \eTeX\ procedures for tr...@>=
procedure file_warning;
var p:pointer; {saved value of |save_ptr| or |cond_ptr|}
@!l:quarterword; {saved value of |cur_level| or |if_limit|}
@!c:quarterword; {saved value of |cur_group| or |cur_if|}
@!i:integer; {saved value of |if_line|}
begin
p:=save_ptr; l:=cur_level; c:=cur_group; save_ptr:=cur_boundary;
while grp_stack[in_open]<>save_ptr do
  begin decr(cur_level);
  print_nl("Warning: end of file when ");
@.Warning: end of file when...@>
  print_group(true); print(" is incomplete");@/
  cur_group:=save_level(save_ptr); save_ptr:=save_index(save_ptr)
  end;
save_ptr:=p; cur_level:=l; cur_group:=c; {restore old values}
p:=cond_ptr; l:=if_limit; c:=cur_if; i:=if_line;
while if_stack[in_open]<>cond_ptr do
  begin print_nl("Warning: end of file when ");
@.Warning: end of file when...@>
  print_cmd_chr(if_test,cur_if);
  if if_limit=fi_code then print_esc("else");
  print_if_line(if_line); print(" is incomplete");@/
  if_line:=if_line_field(cond_ptr); cur_if:=if_limit_subtype(cond_ptr);
  if_limit:=if_limit_type(cond_ptr); cond_ptr:=vlink(cond_ptr);
  end;
cond_ptr:=p; if_limit:=l; cur_if:=c; if_line:=i; {restore old values}
print_ln;
if tracing_nesting>1 then show_context;
if history=spotless then history:=warning_issued;
end;

@ Here are the additional \eTeX\ primitives for expressions.

@<Generate all \eTeX...@>=
primitive_etex("numexpr",last_item,eTeX_expr-int_val+int_val,0);
@!@:num_expr_}{\.{\\numexpr} primitive@>
primitive_etex("dimexpr",last_item,eTeX_expr-int_val+dimen_val,0);
@!@:dim_expr_}{\.{\\dimexpr} primitive@>
primitive_etex("glueexpr",last_item,eTeX_expr-int_val+glue_val,0);
@!@:glue_expr_}{\.{\\glueexpr} primitive@>
primitive_etex("muexpr",last_item,eTeX_expr-int_val+mu_val,0);
@!@:mu_expr_}{\.{\\muexpr} primitive@>

@ This code for reducing |cur_val_level| and\slash or negating the
result is similar to the one for all the other cases of
|scan_something_internal|, with the difference that |scan_expr| has
already increased the reference count of a glue specification.

@<Process an expression and |return|@>=
begin if m<eTeX_mu then
  begin case m of
  @/@<Cases for fetching a glue value@>@/
  end; {there are no other cases}
  cur_val_level:=glue_val;
  end
else if m<eTeX_expr then
  begin case m of
  @/@<Cases for fetching a mu value@>@/
  end; {there are no other cases}
  cur_val_level:=mu_val;
  end
else  begin cur_val_level:=m-eTeX_expr+int_val; scan_expr;
  end;
while cur_val_level>level do
  begin if cur_val_level=glue_val then
    begin m:=cur_val; cur_val:=width(m); delete_glue_ref(m);
    end
  else if cur_val_level=mu_val then mu_error;
  decr(cur_val_level);
  end;
if negative then begin
  if cur_val_level>=glue_val then
    begin m:=cur_val; cur_val:=new_spec(m); delete_glue_ref(m);
    @<Negate all three glue components of |cur_val|@>;
    end
  else negate(cur_val);
  end;
return;
end

@ @<Declare \eTeX\ procedures for sc...@>=
procedure@?scan_expr; forward;@t\2@>

@ The |scan_expr| procedure scans and evaluates an expression.

@<Declare procedures needed for expressions@>=
@t\4@>@<Declare subprocedures for |scan_expr|@>
procedure scan_expr; {scans and evaluates an expression}
label restart, continue, found;
var a,@!b:boolean; {saved values of |arith_error|}
@!l:small_number; {type of expression}
@!r:small_number; {state of expression so far}
@!s:small_number; {state of term so far}
@!o:small_number; {next operation or type of next factor}
@!e:integer; {expression so far}
@!t:integer; {term so far}
@!f:integer; {current factor}
@!n:integer; {numerator of combined multiplication and division}
@!p:pointer; {top of expression stack}
@!q:pointer; {for stack manipulations}
begin l:=cur_val_level; a:=arith_error; b:=false; p:=null;
@<Scan and evaluate an expression |e| of type |l|@>;
if b then
  begin print_err("Arithmetic overflow");
@.Arithmetic overflow@>
  help2("I can't evaluate this expression,")@/
    ("since the result is out of range.");
  error;
  if l>=glue_val then
    begin delete_glue_ref(e); e:=zero_glue; add_glue_ref(e);
    end
  else e:=0;
  end;
arith_error:=a; cur_val:=e; cur_val_level:=l;
end;

@ Evaluating an expression is a recursive process:  When the left
parenthesis of a subexpression is scanned we descend to the next level
of recursion; the previous level is resumed with the matching right
parenthesis.

@d expr_none=0 {\.( seen, or \.( $\langle\it expr\rangle$ \.) seen}
@d expr_add=1 {\.( $\langle\it expr\rangle$ \.+ seen}
@d expr_sub=2 {\.( $\langle\it expr\rangle$ \.- seen}
@d expr_mult=3 {$\langle\it term\rangle$ \.* seen}
@d expr_div=4 {$\langle\it term\rangle$ \./ seen}
@d expr_scale=5 {$\langle\it term\rangle$ \.*
  $\langle\it factor\rangle$ \./ seen}

@<Scan and eval...@>=
restart: r:=expr_none; e:=0; s:=expr_none; t:=0; n:=0;
continue: if s=expr_none then o:=l@+else o:=int_val;
@<Scan a factor |f| of type |o| or start a subexpression@>;
found: @<Scan the next operator and set |o|@>;
arith_error:=b;
@<Make sure that |f| is in the proper range@>;
case s of @<Cases for evaluation of the current term@>@;
end; {there are no other cases}
if o>expr_sub then s:=o@+else @<Evaluate the current expression@>;
b:=arith_error;
if o<>expr_none then goto continue;
if p<>null then @<Pop the expression stack and |goto found|@>

@ @<Scan the next op...@>=
@<Get the next non-blank non-call token@>;
if cur_tok=other_token+"+" then o:=expr_add
else if cur_tok=other_token+"-" then o:=expr_sub
else if cur_tok=other_token+"*" then o:=expr_mult
else if cur_tok=other_token+"/" then o:=expr_div
else  begin o:=expr_none;
  if p=null then
    begin if cur_cmd<>relax then back_input;
    end
  else if cur_tok<>other_token+")" then
    begin print_err("Missing ) inserted for expression");
@.Missing ) inserted@>
    help1("I was expecting to see `+', `-', `*', `/', or `)'. Didn't.");
    back_error;
    end;
  end

@ @<Scan a factor...@>=
@<Get the next non-blank non-call token@>;
if cur_tok=other_token+"(" then
  @<Push the expression stack and |goto restart|@>;
back_input;
if (o=int_val)or(o=attr_val) then scan_int
else if o=dimen_val then scan_normal_dimen
else if o=glue_val then scan_normal_glue
else scan_mu_glue;
f:=cur_val

@ @<Declare \eTeX\ procedures for sc...@>=
procedure@?scan_normal_glue; forward;@t\2@>@/
procedure@?scan_mu_glue; forward;@t\2@>

@ Here we declare to trivial procedures in order to avoid mutually
recursive procedures with parameters.

@<Declare procedures needed for expressions@>=
procedure scan_normal_glue;
begin scan_glue(glue_val);
end;
@#
procedure scan_mu_glue;
begin scan_glue(mu_val);
end;

@ Parenthesized subexpressions can be inside expressions, and this
nesting has a stack.  Seven local variables represent the top of the
expression stack:  |p| points to pushed-down entries, if any; |l|
specifies the type of expression currently beeing evaluated; |e| is the
expression so far and |r| is the state of its evaluation; |t| is the
term so far and |s| is the state of its evaluation; finally |n| is the
numerator for a combined multiplication and division, if any.

@d expr_type(#)==type(#+1)
@d expr_state(#)==subtype(#+1)
@d expr_e_field(#)==vlink(#+1) {saved expression so far}
@d expr_t_field(#)==vlink(#+2) {saved term so far}
@d expr_n_field(#)==vinfo(#+2) {saved numerator}

@<Push the expression...@>=
begin q:=new_node(expr_node,0); vlink(q):=p;
expr_type(q):=l; expr_state(q):=4*s+r;
expr_e_field(q):=e; expr_t_field(q):=t; expr_n_field(q):=n;
p:=q; l:=o; goto restart;
end

@ @<Pop the expression...@>=
begin f:=e; q:=p;
e:=expr_e_field(q); t:=expr_t_field(q); n:=expr_n_field(q);
s:=expr_state(q) div 4; r:=expr_state(q) mod 4;
l:=expr_type(q); p:=vlink(q); flush_node(q);
goto found;
end

@ We want to make sure that each term and (intermediate) result is in
the proper range.  Integer values must not exceed |infinity|
($2^{31}-1$) in absolute value, dimensions must not exceed |max_dimen|
($2^{30}-1$).  We avoid the absolute value of an integer, because this
might fail for the value $-2^{31}$ using 32-bit arithmetic.

@d num_error(#)== {clear a number or dimension and set |arith_error|}
  begin arith_error:=true; #:=0;
  end
@d glue_error(#)== {clear a glue spec and set |arith_error|}
  begin arith_error:=true; delete_glue_ref(#); #:=new_spec(zero_glue);
  end

@<Make sure that |f|...@>=
if ((l=int_val)or(l=attr_val))or(s>expr_sub) then
  begin if (f>infinity)or(f<-infinity) then num_error(f);
  end
else if l=dimen_val then
  begin if abs(f)>max_dimen then num_error(f);
  end
else  begin if (abs(width(f))>max_dimen)or@|
   (abs(stretch(f))>max_dimen)or@|
   (abs(shrink(f))>max_dimen) then glue_error(f);
  end

@ Applying the factor |f| to the partial term |t| (with the operator
|s|) is delayed until the next operator |o| has been scanned.  Here we
handle the first factor of a partial term.  A glue spec has to be copied
unless the next operator is a right parenthesis; this allows us later on
to simply modify the glue components.

@d normalize_glue(#)==
  if stretch(#)=0 then stretch_order(#):=normal;
  if shrink(#)=0 then shrink_order(#):=normal

@<Cases for evaluation of the current term@>=
expr_none: if (l>=glue_val)and(o<>expr_none) then
    begin t:=new_spec(f); delete_glue_ref(f); normalize_glue(t);
    end
  else t:=f;

@ When a term |t| has been completed it is copied to, added to, or
subtracted from the expression |e|.

@d expr_add_sub(#)==add_or_sub(#,r=expr_sub)
@d expr_a(#)==expr_add_sub(#,max_dimen)

@<Evaluate the current expression@>=
begin s:=expr_none;
if r=expr_none then e:=t
else if (l=int_val)or(l=attr_val) then e:=expr_add_sub(e,t,infinity)
else if l=dimen_val then e:=expr_a(e,t)
else @<Compute the sum or difference of two glue specs@>;
r:=o;
end

@ The function |add_or_sub(x,y,max_answer,negative)| computes the sum
(for |negative=false|) or difference (for |negative=true|) of |x| and
|y|, provided the absolute value of the result does not exceed
|max_answer|.

@<Declare subprocedures for |scan_expr|@>=
function add_or_sub(@!x,@!y,@!max_answer:integer;@!negative:boolean):integer;
var a:integer; {the answer}
begin if negative then negate(y);
if x>=0 then
  if y<=max_answer-x then a:=x+y@+else num_error(a)
else if y>=-max_answer-x then a:=x+y@+else num_error(a);
add_or_sub:=a;
end;

@ We know that |stretch_order(e)>normal| implies |stretch(e)<>0| and
|shrink_order(e)>normal| implies |shrink(e)<>0|.

@<Compute the sum or diff...@>=
begin width(e):=expr_a(width(e),width(t));
if stretch_order(e)=stretch_order(t) then
  stretch(e):=expr_a(stretch(e),stretch(t))
else if (stretch_order(e)<stretch_order(t))and(stretch(t)<>0) then
  begin stretch(e):=stretch(t); stretch_order(e):=stretch_order(t);
  end;
if shrink_order(e)=shrink_order(t) then
  shrink(e):=expr_a(shrink(e),shrink(t))
else if (shrink_order(e)<shrink_order(t))and(shrink(t)<>0) then
  begin shrink(e):=shrink(t); shrink_order(e):=shrink_order(t);
  end;
delete_glue_ref(t); normalize_glue(e);
end

@ If a multiplication is followed by a division, the two operations are
combined into a `scaling' operation.  Otherwise the term |t| is
multiplied by the factor |f|.

@d expr_m(#)==#:=nx_plus_y(#,f,0)

@<Cases for evaluation of the current term@>=
expr_mult: if o=expr_div then
    begin n:=f; o:=expr_scale;
    end
  else if (l=int_val)or(l=attr_val) then t:=mult_integers(t,f)
  else if l=dimen_val then expr_m(t)
  else  begin expr_m(width(t)); expr_m(stretch(t)); expr_m(shrink(t));
    end;

@ Here we divide the term |t| by the factor |f|.

@d expr_d(#)==#:=quotient(#,f)

@<Cases for evaluation of the current term@>=
expr_div: if l<glue_val then expr_d(t)
  else  begin expr_d(width(t)); expr_d(stretch(t)); expr_d(shrink(t));
    end;

@ The function |quotient(n,d)| computes the rounded quotient
$q=\lfloor n/d+{1\over2}\rfloor$, when $n$ and $d$ are positive.

@<Declare subprocedures for |scan_expr|@>=
function quotient(@!n,@!d:integer):integer;
var negative:boolean; {should the answer be negated?}
@!a:integer; {the answer}
begin if d=0 then num_error(a)
else  begin if d>0 then negative:=false
  else  begin negate(d); negative:=true;
    end;
  if n<0 then
    begin negate(n); negative:=not negative;
    end;
  a:=n div d; n:=n-a*d; d:=n-d; {avoid certain compiler optimizations!}
  if d+n>=0 then incr(a);
  if negative then negate(a);
  end;
quotient:=a;
end;

@ Here the term |t| is multiplied by the quotient $n/f$.

@d expr_s(#)==#:=fract(#,n,f,max_dimen)

@<Cases for evaluation of the current term@>=
expr_scale: if (l=int_val)or(l=attr_val) then t:=fract(t,n,f,infinity)
  else if l=dimen_val then expr_s(t)
  else  begin expr_s(width(t)); expr_s(stretch(t)); expr_s(shrink(t));
    end;

@ Finally, the function |fract(x,n,d,max_answer)| computes the integer
$q=\lfloor xn/d+{1\over2}\rfloor$, when $x$, $n$, and $d$ are positive
and the result does not exceed |max_answer|.  We can't use floating
point arithmetic since the routine must produce identical results in all
cases; and it would be too dangerous to multiply by~|n| and then divide
by~|d|, in separate operations, since overflow might well occur.  Hence
this subroutine simulates double precision arithmetic, somewhat
analogous to \MF's |make_fraction| and |take_fraction| routines.

@d too_big=88 {go here when the result is too big}

@<Declare subprocedures for |scan_expr|@>=
function fract(@!x,@!n,@!d,@!max_answer:integer):integer;
label found, found1, too_big, done;
var negative:boolean; {should the answer be negated?}
@!a:integer; {the answer}
@!f:integer; {a proper fraction}
@!h:integer; {smallest integer such that |2*h>=d|}
@!r:integer; {intermediate remainder}
@!t:integer; {temp variable}
begin if d=0 then goto too_big;
a:=0;
if d>0 then negative:=false
else  begin negate(d); negative:=true;
  end;
if x<0 then
  begin negate(x); negative:=not negative;
  end
else if x=0 then goto done;
if n<0 then
  begin negate(n); negative:=not negative;
  end;
t:=n div d;
if t>max_answer div x then goto too_big;
a:=t*x; n:=n-t*d;
if n=0 then goto found;
t:=x div d;
if t>(max_answer-a) div n then goto too_big;
a:=a+t*n; x:=x-t*d;
if x=0 then goto found;
if x<n then
  begin t:=x; x:=n; n:=t;
  end; {now |0<n<=x<d|}
@<Compute \(f)$f=\lfloor xn/d+{1\over2}\rfloor$@>@;
if f>(max_answer-a) then goto too_big;
a:=a+f;
found: if negative then negate(a);
goto done;
too_big: num_error(a);
done: fract:=a;
end;

@ The loop here preserves the following invariant relations
between |f|, |x|, |n|, and~|r|:
(i)~$f+\lfloor(xn+(r+d))/d\rfloor=\lfloor x_0n_0/d+{1\over2}\rfloor$;
(ii)~|-d<=r<0<n<=x<d|, where $x_0$, $n_0$ are the original values of~$x$
and $n$.

Notice that the computation specifies |(x-d)+x| instead of |(x+x)-d|,
because the latter could overflow.

@<Compute \(f)$f=\lfloor xn/d+{1\over2}\rfloor$@>=
f:=0; r:=(d div 2)-d; h:=-r;
loop@+begin if odd(n) then
    begin r:=r+x;
    if r>=0 then
      begin r:=r-d; incr(f);
      end;
    end;
  n:=n div 2;
  if n=0 then goto found1;
  if x<h then x:=x+x
  else  begin t:=x-d; x:=t+x; f:=f+n;
      if x<n then
        begin if x=0 then goto found1;
        t:=x; x:=n; n:=t;
        end;
    end;
  end;
found1:

@ The \.{\\gluestretch}, \.{\\glueshrink}, \.{\\gluestretchorder}, and
\.{\\glueshrinkorder} commands return the stretch and shrink components
and their orders of ``infinity'' of a glue specification.

@d glue_stretch_order_code=eTeX_int+6 {code for \.{\\gluestretchorder}}
@d glue_shrink_order_code=eTeX_int+7 {code for \.{\\glueshrinkorder}}
@d glue_stretch_code=eTeX_dim+7 {code for \.{\\gluestretch}}
@d glue_shrink_code=eTeX_dim+8 {code for \.{\\glueshrink}}

@<Generate all \eTeX...@>=
primitive_etex("gluestretchorder",last_item,glue_stretch_order_code,0);
@!@:glue_stretch_order_}{\.{\\gluestretchorder} primitive@>
primitive_etex("glueshrinkorder",last_item,glue_shrink_order_code,0);
@!@:glue_shrink_order_}{\.{\\glueshrinkorder} primitive@>
primitive_etex("gluestretch",last_item,glue_stretch_code,0);
@!@:glue_stretch_}{\.{\\gluestretch} primitive@>
primitive_etex("glueshrink",last_item,glue_shrink_code,0);
@!@:glue_shrink_}{\.{\\glueshrink} primitive@>

@ @<Cases for fetching an integer value@>=
glue_stretch_order_code, glue_shrink_order_code:
  begin scan_normal_glue; q:=cur_val;
  if m=glue_stretch_order_code then cur_val:=stretch_order(q)
  else cur_val:=shrink_order(q);
  delete_glue_ref(q);
  end;

@ @<Cases for fetching a dimension value@>=
glue_stretch_code, glue_shrink_code:
  begin scan_normal_glue; q:=cur_val;
  if m=glue_stretch_code then cur_val:=stretch(q)
  else cur_val:=shrink(q);
  delete_glue_ref(q);
  end;

@ The \.{\\mutoglue} and \.{\\gluetomu} commands convert ``math'' glue
into normal glue and vice versa; they allow to manipulate math glue with
\.{\\gluestretch} etc.

@d mu_to_glue_code=eTeX_glue {code for \.{\\mutoglue}}
@d glue_to_mu_code=eTeX_mu {code for \.{\\gluetomu}}

@<Generate all \eTeX...@>=
primitive_etex("mutoglue",last_item,mu_to_glue_code,0);
@!@:mu_to_glue_}{\.{\\mutoglue} primitive@>
primitive_etex("gluetomu",last_item,glue_to_mu_code,0);
@!@:glue_to_mu_}{\.{\\gluetomu} primitive@>

@ @<Cases for fetching a glue value@>=
mu_to_glue_code: scan_mu_glue;

@ @<Cases for fetching a mu value@>=
glue_to_mu_code: scan_normal_glue;

@ @<Glob...@>=
@!last_line_fill:pointer; {the |par_fill_skip| glue node of the new paragraph}

@ When |saving_vdiscards| is positive then the glue, kern, and penalty
nodes removed by the page builder or by \.{\\vsplit} from the top of a
vertical list are saved in special lists instead of being discarded.

@d tail_page_disc==disc_ptr[copy_code] {last item removed by page builder}
@d page_disc==disc_ptr[last_box_code] {first item removed by page builder}
@d split_disc==disc_ptr[vsplit_code] {first item removed by \.{\\vsplit}}

@<Glob...@>=
@!disc_ptr:array[copy_code..vsplit_code] of pointer; {list pointers}

@ @<Set init...@>=
page_disc:=null; split_disc:=null;

@ The \.{\\pagediscards} and \.{\\splitdiscards} commands share the
command code |un_vbox| with \.{\\unvbox} and \.{\\unvcopy}, they are
distinguished by their |chr_code| values |last_box_code| and
|vsplit_code|.  These |chr_code| values are larger than |box_code| and
|copy_code|.

@<Generate all \eTeX...@>=
primitive_etex("pagediscards",un_vbox,last_box_code,0);@/
@!@:page_discards_}{\.{\\pagediscards} primitive@>
primitive_etex("splitdiscards",un_vbox,vsplit_code,0);@/
@!@:split_discards_}{\.{\\splitdiscards} primitive@>

@ @<Handle saved items and |goto done|@>=
begin vlink(tail):=disc_ptr[cur_chr]; disc_ptr[cur_chr]:=null;
goto done;
end

@ The \.{\\interlinepenalties}, \.{\\clubpenalties}, \.{\\widowpenalties},
and \.{\\displaywidowpenalties} commands allow to define arrays of
penalty values to be used instead of the corresponding single values.

@d inter_line_penalties_ptr==equiv(inter_line_penalties_loc)
@d club_penalties_ptr==equiv(club_penalties_loc)
@d widow_penalties_ptr==equiv(widow_penalties_loc)
@d display_widow_penalties_ptr==equiv(display_widow_penalties_loc)

@<Generate all \eTeX...@>=
primitive_etex("interlinepenalties",set_etex_shape,inter_line_penalties_loc,etex_pen_base);@/
@!@:inter_line_penalties_}{\.{\\interlinepenalties} primitive@>
primitive_etex("clubpenalties",set_etex_shape,club_penalties_loc,etex_pen_base);@/
@!@:club_penalties_}{\.{\\clubpenalties} primitive@>
primitive_etex("widowpenalties",set_etex_shape,widow_penalties_loc,etex_pen_base);@/
@!@:widow_penalties_}{\.{\\widowpenalties} primitive@>
primitive_etex("displaywidowpenalties",set_etex_shape,display_widow_penalties_loc,etex_pen_base);@/
@!@:display_widow_penalties_}{\.{\\displaywidowpenalties} primitive@>

@ @<Fetch a penalties array element@>=
begin scan_int;
if (equiv(m)=null)or(cur_val<0) then cur_val:=0
else  begin if cur_val>penalty(equiv(m)) then cur_val:=penalty(equiv(m));
  cur_val:=penalty(equiv(m)+cur_val);
  end;
cur_val_level:=int_val;
end

@ This is needed to get the relative order of the marks code correct

@<Show the meaning of a mark node@>=
if (cur_cmd=top_bot_mark)and(cur_chr<marks_code) then
  begin print_char(":"); print_ln;
  case cur_chr of
    first_mark_code:       token_show(first_mark(0));
    bot_mark_code:         token_show(bot_mark(0));
    split_first_mark_code: token_show(split_first_mark(0));
    split_bot_mark_code:   token_show(split_bot_mark(0));
    othercases             token_show(top_mark(0));
  endcases;
end


@ The lua interface needs some extra pascal functions. The functions
themselves are quite boring, but they are handy because otherwise this
internal stuff has to be accessed from C directly, where lots of the
pascal defines are not available.

@p function get_tex_dimen_register (j:integer):scaled;
begin
  get_tex_dimen_register := dimen(j);
end;

function set_tex_dimen_register (j:integer;v:scaled):integer;
var a:small_number;
begin  {return non-nil for error}
if global_defs>0 then  a:=4 else a:=0;
word_define(j+scaled_base,v);
set_tex_dimen_register := 0;
end;

function get_tex_skip_register (j:integer):halfword;
begin
  get_tex_skip_register := skip(j);
end;

function set_tex_skip_register (j:integer;v:halfword):integer;
var a:small_number;
begin  {return non-nil for error}
  if global_defs>0 then  a:=4 else a:=0;
  if type(v) <> glue_spec_node then
    set_tex_skip_register := 1
  else begin
    word_define(j+skip_base,v);
    set_tex_skip_register := 0;
  end;
end;

function get_tex_count_register (j:integer):scaled;
begin
  get_tex_count_register := count(j);
end;

function set_tex_count_register (j:integer;v:scaled):integer;
var a:small_number;
begin  {return non-nil for error}
  if global_defs>0 then  a:=4 else a:=0;
  word_define(j+count_base,v);
  set_tex_count_register := 0;
end;

function get_tex_attribute_register (j:integer):scaled;
begin
  get_tex_attribute_register := attribute(j);
end;

function set_tex_attribute_register (j:integer;v:scaled):integer;
var a:small_number;
begin  {return non-nil for error}
if global_defs>0 then  a:=4 else a:=0;
if (j)>max_used_attr then max_used_attr:=(j);
attr_list_cache:=cache_disabled;
word_define(j+attribute_base,v);
set_tex_attribute_register := 0;
end;

function get_tex_toks_register (j:integer):str_number;
var s:str_number;
begin
  s:="";
  if toks(j) <> min_halfword then begin
        s := tokens_to_string(toks(j));
  end;
  get_tex_toks_register := s;
end;

function set_tex_toks_register (j:integer;s:str_number):integer;
var s_pool_ptr:pool_pointer;
  ref:pointer;
  a:small_number;
  junk:pointer;
begin
  set_tex_toks_register := 0;
  s_pool_ptr := pool_ptr;
  pool_ptr := str_start_macro(s+1);
  ref := get_avail;
  junk := str_toks(str_start_macro(s));
  pool_ptr := s_pool_ptr;
  token_ref_count(ref) := 0;
  link(ref) := link(temp_token_head);
  if global_defs>0 then  a:=4 else a:=0;
  define(j+toks_base,call,ref);
  flush_str(s);
end;

function get_tex_box_register (j:integer):integer;
begin
  get_tex_box_register := box(j);
end;

function set_tex_box_register (j:integer;v:scaled):integer;
var a:small_number;
begin  {return non-nil for error}
if global_defs>0 then  a:=4 else a:=0;
define(j+box_base,box_ref,v);
set_tex_box_register := 0;
end;


function get_tex_box_width (j:integer):scaled;
var q:pointer;
begin
 q := box(j);
 get_tex_box_width := 0;
 if q <> null then
    get_tex_box_width := width(q);
end;

function set_tex_box_width (j:integer;v:scaled):integer;
var q:pointer;
begin
  q := box(j);
  set_tex_box_width := 0;
  if q <> null then
    width(q) := v
  else
    set_tex_box_width := 1;
end;

function get_tex_box_height (j:integer):scaled;
var q:pointer;
begin
 q := box(j);
 get_tex_box_height := 0;
 if q <> null then
    get_tex_box_height := height(q);
end;

function set_tex_box_height (j:integer;v:scaled):integer;
var q:pointer;
begin
  q := box(j);
  set_tex_box_height := 0;
  if q <> null then
    height(q) := v
  else
    set_tex_box_height := 1;
end;

function get_tex_box_depth (j:integer):scaled;
var q:pointer;
begin
 q := box(j);
 get_tex_box_depth := 0;
 if q <> null then
    get_tex_box_depth := depth(q);
end;

function set_tex_box_depth (j:integer;v:scaled):integer;
var q:pointer;
begin
  q := box(j);
  set_tex_box_depth := 0;
  if q <> null then
    depth(q) := v
  else
    set_tex_box_depth := 1;
end;

function get_cur_v: integer;
begin
    get_cur_v := cur_page_size.v - cur.v;
end;

function get_cur_h: integer;
begin
    get_cur_h := cur.h;
end;

@* \[54] $\Omega$ changes.

@ Here we do the main work required for reading and interpreting
  $\Omega$ Compiled Translation Processes.

@ Here are all the instructions in our mini-assembler.
@d otp_right_output=1
@d otp_right_num=2
@d otp_right_char=3
@d otp_right_lchar=4
@d otp_right_some=5

@d otp_pback_output=6
@d otp_pback_num=7
@d otp_pback_char=8
@d otp_pback_lchar=9
@d otp_pback_some=10

@d otp_add=11
@d otp_sub=12
@d otp_mult=13
@d otp_div=14
@d otp_mod=15
@d otp_lookup=16
@d otp_push_num=17
@d otp_push_char=18
@d otp_push_lchar=19

@d otp_state_change=20
@d otp_state_push=21
@d otp_state_pop=22

@d otp_left_start=23
@d otp_left_return=24
@d otp_left_backup=25

@d otp_goto=26
@d otp_goto_ne=27
@d otp_goto_eq=28
@d otp_goto_lt=29
@d otp_goto_le=30
@d otp_goto_gt=31
@d otp_goto_ge=32
@d otp_goto_no_advance=33
@d otp_goto_beg=34
@d otp_goto_end=35

@d otp_stop=36

@
@<Glob...@>=
@!otp_init_input_start:halfword;
@!otp_init_input_last:halfword;
@!otp_init_input_end:halfword;
@!otp_i:halfword;
@!otp_init_input_buf:array[0..20000] of quarterword;

@!otp_input_start:halfword;
@!otp_input_last:halfword;
@!otp_input_end:halfword;
@!otp_input_buf:array[0..20000] of quarterword;

@!otp_output_end:halfword;
@!otp_output_buf:array[0..20000] of quarterword;

@!otp_stack_used:halfword;
@!otp_stack_last:halfword;
@!otp_stack_new:halfword;
@!otp_stack_buf:array[0..1000] of quarterword;

@!otp_pc:halfword;

@!otp_calc_ptr:halfword;
@!otp_calcs:array[0..1000] of halfword;
@!otp_state_ptr:halfword;
@!otp_states:array[0..1000] of halfword;

@!otp_input_char:halfword;
@!otp_calculated_char:halfword;
@!otp_no_input_chars:halfword;

@!otp_instruction:halfword;
@!otp_instr:halfword;
@!otp_arg:halfword;
@!otp_first_arg:halfword;
@!otp_second_arg:halfword;

@!otp_input_ocp:halfword;
@!otp_counter:halfword;

@!otp_finished:boolean;
@!otp_ext_str:integer;
@!otp_ext_str_arg:integer;
@!otp_ext_i:integer;

@
@<Initialize table...@>=

@
@<Create a buffer with character |cur_chr| and the following
  characters (if~any) and then apply the current active OCP filter
  to this buffer@>=
begin
@<Read in the buffer for treatment@>;
@<Apply the OCP to the input buffer@>;
@<Place the output buffer back on the stream@>;
goto big_switch;
end;

@ The OTP input buffer is an array of 16-bit values.
In the future, the range |@"D800| \dots |@"DFFF| will be used for
surrogate pairs, so it cannot be used for simple 16-bit values
like it is in Omega, so a future incompatibility with Aleph is
unavoidable.

@<Read in the buffer for treatment@>=
begin
otp_init_input_end:=0;
while (cur_cmd=letter) or (cur_cmd=other_char) or
      (cur_cmd=char_given) or (cur_cmd=spacer) do begin
  incr(otp_init_input_end);
  if otp_init_input_end >ocp_buf_size then
    overflow_ocp_buf_size;
  { |cur_chr| can cover the full range |0..0x10FFFF| }
  if cur_chr<@"10000 then
    otp_init_input_buf[otp_init_input_end]:=cur_chr
  else begin
    otp_init_input_buf[otp_init_input_end]:=((cur_chr - @"10000) div @"400) + @"D800;
    incr(otp_init_input_end);
    if otp_init_input_end >ocp_buf_size then
      overflow_ocp_buf_size;
    otp_init_input_buf[otp_init_input_end]:=((cur_chr - @"10000) mod @"400) + @"DC00;
    end;
  get_token;
  if (cur_cmd<>letter) and (cur_cmd<>other_char) and
     (cur_cmd<>char_given) then begin
    x_token;
    if (cur_cmd=char_num) then begin
      scan_char_num; cur_cmd:=other_char; cur_chr:=cur_val;
      end;
    end;
  end;
back_input;
otp_input_end:=otp_init_input_end;
for otp_i:=0 to otp_init_input_end do begin
  otp_input_buf[otp_i]:=otp_init_input_buf[otp_i];
  end;
end

@
@<Apply the OCP to the input buffer@>=
begin
otp_input_ocp:=active_ocp(active_real);
if otp_input_ocp=0 then begin
  print_err("Null ocp being used: all input lost");
  error;
  otp_output_end:=0;
  end
else if ocp_external(otp_input_ocp)=0 then begin
  otp_input_start:=0;
  otp_input_last:=0;
  otp_stack_used:=0;
  otp_stack_last:=0;
  otp_stack_new:=0;
  otp_output_end:=0;
  otp_pc:=0;
  otp_finished:=false;
  otp_calc_ptr:=0;
  otp_calcs[otp_calc_ptr]:=0;
  otp_state_ptr:=0;
  otp_states[otp_state_ptr]:=0;
  while not otp_finished do
    @<Run the OTP program@>;
  end
else begin
  k:=0;
  if nameoffile then libcfree (nameoffile);
  otp_ext_str:=ocp_external(otp_input_ocp);
  otp_ext_str_arg:=ocp_external_arg(otp_input_ocp);
  nameoffile := xmalloc (4 + length(otp_ext_str) + length(otp_ext_str_arg));
  for otp_ext_i:=str_start_macro(otp_ext_str) to
         str_start_macro(otp_ext_str)+length(otp_ext_str)-1 do
    append_to_name(str_pool[otp_ext_i]);
  append_to_name(" ");
  for otp_ext_i:=str_start_macro(otp_ext_str_arg) to
         str_start_macro(otp_ext_str_arg)+length(otp_ext_str_arg)-1 do
    append_to_name(str_pool[otp_ext_i]);
  nameoffile[length(otp_ext_str)+length(otp_ext_str_arg)+2]:=0;
  run_external_ocp(nameoffile);
  end
end

@ The OTP output buffer is an array of 16-bit values. To convert back
to the |buffer| it has to be re-encoded into UTF-8. An incompatibility
with Aleph is unavoidable here: The range |@"D800| \dots |@"DFFF| is
used for surrogate pairs, not for simple 16-bit values.

@<Place the output buffer back on the stream@>=
begin
if (first+otp_output_end)>=ocp_buf_size then
  overflow_ocp_buf_size;
push_input;
current_ocp_lstack:=active_lstack_no(active_real);
current_ocp_no:=active_counter(active_real);
state:=mid_line;
start:=first;
last:=start;
loc:=start;
line_catcode_table:=DEFAULT_CAT_TABLE; line_partial:=false;
for otp_counter:=1 to otp_output_end do begin
    { convert back to utf-8 }
        t := otp_output_buf[otp_counter];
        if otp_counter < otp_output_end then begin
            if ((t>=@"D800) and (t<@"DC00)) then begin
                if (otp_output_buf[otp_counter+1]>=@"DC00)
                    and (otp_output_buf[otp_counter+1]<@"E000) then begin
                    incr(otp_counter);
                    t := (t-@"D800) * @"400 + (otp_output_buf[otp_counter]-@"DC00) + @"10000;
                end
                else if ((t>=@"DC00) and (t<@"E000)) then
                    if (otp_output_buf[otp_counter+1]>=@"D800)
                        and (otp_output_buf[otp_counter+1]<@"DC00) then begin
                        incr(otp_counter);
                        t := (otp_output_buf[otp_counter]-@"D800) * @"400 + (t-@"DC00) + @"10000;
                    end;
            end;
        end;
    if t <= @"7F then
      buffer[last]:= t
    else if t<=@"7FF then begin
      buffer[last]:=@"C0 + t div @"40;
      incr(last);
      if last=buf_size-2 then
        @<Report overflow of the input buffer, and abort@>;
      buffer[last]:=@"80 + t mod @"40;
      end
    else if t<=@"FFFF then      begin
      buffer[last]:=@"E0 + t div @"1000;
      incr(last);
      if last=buf_size-2 then
        @<Report overflow of the input buffer, and abort@>;
      buffer[last]:=@"80 + (t mod @"1000) div @"40;
      incr(last);
      if last=buf_size-2 then
        @<Report overflow of the input buffer, and abort@>;
      buffer[last]:=@"80 + (t mod @"1000) mod @"40;
      end
    else begin
      buffer[last]:=@"F0 + t div @"40000;
      incr(last);
      if last=buf_size-2 then
        @<Report overflow of the input buffer, and abort@>;
      buffer[last]:=@"80 + (t mod @"40000) div @"1000;
      incr(last);
      if last=buf_size-2 then
        @<Report overflow of the input buffer, and abort@>;
      buffer[last]:=@"80 + ((t mod @"40000) mod @"1000) div @"40;
      incr(last);
      if last=buf_size-2 then
        @<Report overflow of the input buffer, and abort@>;
      buffer[last]:=@"80 + ((t mod @"40000) mod @"1000) mod @"40;
      end;
    incr(last);
    if last=buf_size-2 then
      @<Report overflow of the input buffer, and abort@>;
  end;
limit:=last-1;
if (t>@"FFFF) then decr(limit);
if (t>@"7FF)  then decr(limit);
if (t>@"7F)   then decr(limit);
first:=last;
end

@
@d otp_cur_state==otp_states[otp_state_ptr]
@d otp_set_instruction==begin
if otp_pc>=ocp_state_no(otp_input_ocp)(otp_cur_state) then begin
  print_err("bad OCP program -- PC not valid");
  succumb;
  end;
otp_instruction:=ocp_state_entry(otp_input_ocp)(otp_cur_state)(otp_pc);
otp_instr:=otp_instruction div @"1000000;
otp_arg:=otp_instruction mod @"1000000;
end

@<Run the OTP program@>=
begin
otp_set_instruction;
case otp_instr of
  @<Run the |otp_right| instructions@>;
  @<Run the |otp_pback| instructions@>;
  @<Run the arithmetic instructions@>;
  @<Run the |otp_state| instructions@>;
  @<Run the |otp_left| instructions@>;
  @<Run the |otp_goto| instructions@>;
  @<Run the |otp_stop| instruction@>;
  othercases begin
    print_err("bad OCP program -- unknown instruction");
    succumb;
    end
  endcases;
end

@

@d otp_check_char(#)==
if (1>#) or (#>otp_no_input_chars) then begin
  print_err("right hand side of OCP expression is bad");
  succumb;
  end

@d otp_get_char(#)==begin
otp_check_char(#);
if #>otp_stack_last then begin
  otp_calculated_char:=otp_input_buf[otp_input_start+#-otp_stack_last];
  end
else begin
  otp_calculated_char:=otp_stack_buf[#];
  end;
end

@<Run the |otp_right| instructions@>=
  otp_right_output: begin
    incr(otp_output_end);
    if otp_output_end >ocp_buf_size then
      overflow_ocp_buf_size;
    otp_output_buf[otp_output_end]:=otp_calcs[otp_calc_ptr];
    decr(otp_calc_ptr);
    incr(otp_pc);
    end;
  otp_right_num: begin
    incr(otp_output_end);
    if otp_output_end >ocp_buf_size then
      overflow_ocp_buf_size;
    otp_output_buf[otp_output_end]:=otp_arg;
    incr(otp_pc);
    end;
  otp_right_char: begin
    otp_get_char(otp_arg);
    incr(otp_output_end);
    if otp_output_end >ocp_buf_size then
      overflow_ocp_buf_size;
    otp_output_buf[otp_output_end]:=otp_calculated_char;
    incr(otp_pc);
    end;
  otp_right_lchar: begin
    otp_get_char(otp_no_input_chars-otp_arg);
    incr(otp_output_end);
    if otp_output_end >ocp_buf_size then
      overflow_ocp_buf_size;
    otp_output_buf[otp_output_end]:=otp_calculated_char;
    incr(otp_pc);
    end;
  otp_right_some: begin
    otp_first_arg:=otp_arg+1;
    incr(otp_pc);
    otp_set_instruction;
    otp_second_arg:=otp_no_input_chars-otp_arg;
    for otp_counter:=otp_first_arg to otp_second_arg do begin
      otp_get_char(otp_counter);
      incr(otp_output_end);
      if otp_output_end >ocp_buf_size then
        overflow_ocp_buf_size;
      otp_output_buf[otp_output_end]:=otp_calculated_char;
      end;
    incr(otp_pc);
    end

@
@<Run the |otp_pback| instructions@>=
  otp_pback_output: begin
    incr(otp_stack_new);
    if otp_stack_new >= ocp_stack_size then
      overflow_ocp_stack_size;
    otp_stack_buf[otp_stack_new]:=otp_calcs[otp_calc_ptr];
    decr(otp_calc_ptr);
    incr(otp_pc);
    end;
  otp_pback_num: begin
    incr(otp_stack_new);
    if otp_stack_new >= ocp_stack_size then
      overflow_ocp_stack_size;
    otp_stack_buf[otp_stack_new]:=otp_arg;
    incr(otp_pc);
    end;
  otp_pback_char: begin
    otp_get_char(otp_arg);
    incr(otp_stack_new);
    if otp_stack_new >= ocp_stack_size then
      overflow_ocp_stack_size;
    otp_stack_buf[otp_stack_new]:=otp_calculated_char;
    incr(otp_pc);
    end;
  otp_pback_lchar: begin
    otp_get_char(otp_no_input_chars-otp_arg);
    incr(otp_stack_new);
    if otp_stack_new >= ocp_stack_size then
      overflow_ocp_stack_size;
    otp_stack_buf[otp_stack_new]:=otp_calculated_char;
    incr(otp_pc);
    end;
  otp_pback_some: begin
    otp_first_arg:=otp_arg+1;
    incr(otp_pc);
    otp_set_instruction;
    otp_second_arg:=otp_no_input_chars-otp_arg;
    for otp_counter:=otp_first_arg to otp_second_arg do begin
      otp_get_char(otp_counter);
      incr(otp_stack_new);
      if otp_stack_new >= ocp_stack_size then
        overflow_ocp_stack_size;
      otp_stack_buf[otp_stack_new]:=otp_calculated_char;
      end;
    incr(otp_pc);
    end

@
@<Run the arithmetic instructions@>=
  otp_add: begin
    otp_calcs[otp_calc_ptr-1] :=
      otp_calcs[otp_calc_ptr-1] + otp_calcs[otp_calc_ptr];
    incr(otp_pc);
    decr(otp_calc_ptr);
    end;
  otp_sub: begin
    otp_calcs[otp_calc_ptr-1] :=
      otp_calcs[otp_calc_ptr-1] - otp_calcs[otp_calc_ptr];
    incr(otp_pc);
    decr(otp_calc_ptr);
    end;
  otp_mult: begin
    otp_calcs[otp_calc_ptr-1] :=
      otp_calcs[otp_calc_ptr-1] * otp_calcs[otp_calc_ptr];
    incr(otp_pc);
    decr(otp_calc_ptr);
    end;
  otp_div: begin
    otp_calcs[otp_calc_ptr-1] :=
      otp_calcs[otp_calc_ptr-1] div otp_calcs[otp_calc_ptr];
    incr(otp_pc);
    decr(otp_calc_ptr);
    end;
  otp_mod: begin
    otp_calcs[otp_calc_ptr-1] :=
      otp_calcs[otp_calc_ptr-1] mod otp_calcs[otp_calc_ptr];
    incr(otp_pc);
    decr(otp_calc_ptr);
    end;
  otp_lookup: begin
    if otp_calcs[otp_calc_ptr]>=
       ocp_table_no(otp_input_ocp)(otp_calcs[otp_calc_ptr-1]) then begin
      print_err("bad OCP program -- table index not valid");
      succumb;
      end;
    otp_calcs[otp_calc_ptr-1]:=
    ocp_table_entry(otp_input_ocp)(otp_calcs[otp_calc_ptr-1])
                   (otp_calcs[otp_calc_ptr]);
    incr(otp_pc);
    decr(otp_calc_ptr);
    end;
  otp_push_num: begin
    incr(otp_calc_ptr);
    if otp_calc_ptr >= ocp_stack_size then
      overflow_ocp_stack_size;
    otp_calcs[otp_calc_ptr]:=otp_arg;
    incr(otp_pc);
    end;
  otp_push_char: begin
    otp_get_char(otp_arg);
    incr(otp_calc_ptr);
    if otp_calc_ptr >= ocp_stack_size then
      overflow_ocp_stack_size;
    otp_calcs[otp_calc_ptr]:=otp_calculated_char;
    incr(otp_pc);
    end;
  otp_push_lchar: begin
    otp_get_char(otp_no_input_chars-otp_arg);
    incr(otp_calc_ptr);
    if otp_calc_ptr >= ocp_stack_size then
      overflow_ocp_stack_size;
    otp_calcs[otp_calc_ptr]:=otp_calculated_char;
    incr(otp_pc);
    end

@
@<Run the |otp_state| instructions@>=
  otp_state_change: begin
    otp_input_start:=otp_input_last;
    for otp_counter:=1 to (otp_stack_new-otp_stack_used) do begin
      otp_stack_buf[otp_counter] :=
        otp_stack_buf[otp_counter+otp_stack_used];
      end;
    otp_stack_new:=otp_stack_new-otp_stack_used;
    otp_stack_last:=otp_stack_new;
    otp_stack_used:=0;
    otp_states[otp_state_ptr]:=otp_arg;
    otp_pc:=0;
    end;
  otp_state_push: begin
    otp_input_start:=otp_input_last;
    for otp_counter:=1 to (otp_stack_new-otp_stack_used) do begin
      otp_stack_buf[otp_counter] :=
        otp_stack_buf[otp_counter+otp_stack_used];
      end;
    otp_stack_new:=otp_stack_new-otp_stack_used;
    otp_stack_last:=otp_stack_new;
    otp_stack_used:=0;
    incr(otp_state_ptr);
    if otp_state_ptr >= ocp_stack_size then
      overflow_ocp_stack_size;
    otp_states[otp_state_ptr]:=otp_arg;
    otp_pc:=0;
    end;
  otp_state_pop: begin
    otp_input_start:=otp_input_last;
    for otp_counter:=1 to (otp_stack_new-otp_stack_used) do begin
      otp_stack_buf[otp_counter] :=
        otp_stack_buf[otp_counter+otp_stack_used];
      end;
    otp_stack_new:=otp_stack_new-otp_stack_used;
    otp_stack_last:=otp_stack_new;
    otp_stack_used:=0;
    if otp_state_ptr>0 then decr(otp_state_ptr);
    otp_pc:=0;
    end

@
@<Run the |otp_left| instructions@>=
  otp_left_start: begin
    otp_input_start:=otp_input_last;
    otp_input_last:=otp_input_start;
    otp_stack_used:=0;
    if (otp_stack_last=0) and (otp_input_last>=otp_input_end) then
      otp_finished:=true
    else if (otp_stack_used < otp_stack_last) then begin
      incr(otp_stack_used); {no overflow problem}
      otp_input_char:=otp_stack_buf[otp_stack_used];
      otp_no_input_chars:=1;
      incr(otp_pc);
      end
    else begin
      incr(otp_input_last); {no overflow problem}
      otp_input_char:=otp_input_buf[otp_input_last];
      otp_no_input_chars:=1;
      incr(otp_pc);
      end;
    end;
  otp_left_return: begin
    otp_input_last:=otp_input_start;
    otp_stack_used:=0;
    if (otp_stack_used < otp_stack_last) then begin
      incr(otp_stack_used); {no overflow problem}
      otp_input_char:=otp_stack_buf[otp_stack_used];
      otp_no_input_chars:=1;
      incr(otp_pc);
      end
    else begin
      incr(otp_input_last); {no overflow problem}
      otp_input_char:=otp_input_buf[otp_input_last];
      otp_no_input_chars:=1;
      incr(otp_pc);
      end;
    end;
  otp_left_backup: begin
    if otp_input_start < otp_input_last then begin
      decr(otp_input_last); otp_input_char:=otp_input_buf[otp_input_last];
      end
    else begin
      decr(otp_stack_used); otp_input_char:=otp_stack_buf[otp_stack_used];
      end;
    decr(otp_no_input_chars);
    incr(otp_pc);
    end

@
@<Run the |otp_goto| instructions@>=
  otp_goto: begin
    otp_pc:=otp_arg;
    end;
  otp_goto_ne: begin
    otp_first_arg:=otp_arg;
    incr(otp_pc);
    otp_set_instruction;
    if otp_input_char <> otp_first_arg then begin
      otp_pc:=otp_arg;
      end
    else begin
      incr(otp_pc);
      end;
    end;
  otp_goto_eq: begin
    otp_first_arg:=otp_arg;
    incr(otp_pc);
    otp_set_instruction;
    if otp_input_char = otp_first_arg then begin
      otp_pc:=otp_arg;
      end
    else begin
      incr(otp_pc);
      end;
    end;
  otp_goto_lt: begin
    otp_first_arg:=otp_arg;
    incr(otp_pc);
    otp_set_instruction;
    if otp_input_char < otp_first_arg then begin
      otp_pc:=otp_arg;
      end
    else begin
      incr(otp_pc);
      end;
   end;
  otp_goto_le: begin
    otp_first_arg:=otp_arg;
    incr(otp_pc);
    otp_set_instruction;
    if otp_input_char <= otp_first_arg then begin
      otp_pc:=otp_arg;
      end
    else begin
      incr(otp_pc);
      end;
    end;
  otp_goto_gt: begin
    otp_first_arg:=otp_arg;
    incr(otp_pc);
    otp_set_instruction;
    if otp_input_char > otp_first_arg then begin
      otp_pc:=otp_arg;
      end
    else begin
      incr(otp_pc);
      end;
    end;
  otp_goto_ge: begin
    otp_first_arg:=otp_arg;
    incr(otp_pc);
    otp_set_instruction;
    if otp_input_char >= otp_first_arg then begin
      otp_pc:=otp_arg;
      end
    else begin
      incr(otp_pc);
      end;
    end;
  otp_goto_no_advance: begin
    if (otp_stack_used < otp_stack_last) then begin
      incr(otp_stack_used); {no overflow problem}
      otp_input_char:=otp_stack_buf[otp_stack_used];
      incr(otp_no_input_chars); {no overflow problem}
      incr(otp_pc);
      end
    else if otp_input_last>=otp_input_end then begin
      otp_pc:=otp_arg;
      end
    else begin
      incr(otp_input_last); {no overflow problem}
      otp_input_char:=otp_input_buf[otp_input_last];
      incr(otp_no_input_chars); {no overflow problem}
      incr(otp_pc);
      end;
    end;
  otp_goto_beg: begin
    if otp_input_last=0 then begin
      otp_pc:=otp_arg;
      end
    else begin
      incr(otp_pc);
      end;
    end;
  otp_goto_end: begin
    if otp_input_last>=otp_input_end then begin
      otp_pc:=otp_arg;
      end
    else begin
      incr(otp_pc);
      end;
    end

@
@<Run the |otp_stop| instruction@>=
  otp_stop: begin
    otp_input_start:=otp_input_last;
    for otp_counter:=1 to (otp_stack_new-otp_stack_used) do begin
      otp_stack_buf[otp_counter] :=
        otp_stack_buf[otp_counter+otp_stack_used];
      end;
    otp_stack_new:=otp_stack_new-otp_stack_used;
    otp_stack_last:=otp_stack_new;
    otp_stack_used:=0;
    otp_pc:=0;
    end

@ @<Put each...@>=
primitive_omega("ocp", def_ocp, 0,0);
primitive_omega("externalocp", def_ocp, 1,0);
primitive_omega("ocplist", def_ocp_list, 0,0);
primitive_omega("pushocplist", push_ocp_list, 0,0);
primitive_omega("popocplist", pop_ocp_list, 0,0);
primitive_omega("clearocplists", clear_ocp_lists, 0,0);
primitive_omega("addbeforeocplist", ocp_list_op, add_before_op,0);
primitive_omega("addafterocplist", ocp_list_op, add_after_op,0);
primitive_omega("removebeforeocplist", ocp_list_op, remove_before_op,0);
primitive_omega("removeafterocplist", ocp_list_op, remove_after_op,0);
primitive_omega("ocptracelevel", ocp_trace_level, 0,0);
equiv(ocp_trace_level_base):=0;

@ @<Assignments@>=
set_ocp: begin
  print_err("To use ocps, use the "); print_esc("pushocplist");
  print(" primitive");print_ln
  end;
def_ocp: new_ocp(a);
set_ocp_list: begin
  print_err("To use ocp lists, use the ");
  print_esc("pushocplist"); print(" primitive");print_ln
  end;
def_ocp_list: new_ocp_list(a);
push_ocp_list: do_push_ocp_list(a);
pop_ocp_list: do_pop_ocp_list(a);
clear_ocp_lists: do_clear_ocp_lists(a);
ocp_list_op: begin
  print_err("To build ocp lists, use the ");
  print_esc("ocplist"); print(" primitive"); print_ln
  end;
ocp_trace_level: begin scan_optional_equals; scan_int;
  if cur_val<>0 then cur_val:=1;
  define(ocp_trace_level_base, data, cur_val);
  end;

@ @<Declare subprocedures for |prefixed_command|@>=
procedure new_ocp(@!a:small_number);
label common_ending;
var u:pointer; {user's ocp identifier}
@!f:internal_ocp_number; {runs through existing ocps}
@!t:str_number; {name for the frozen ocp identifier}
@!flushable_string:str_number; {string not yet referenced}
@!external_ocp:boolean; {external binary file}
begin if job_name=0 then open_log_file;
  {avoid confusing \.{texput} with the ocp name}
@.texput@>
if cur_chr=1 then external_ocp:=true
else external_ocp:=false;
get_r_token; u:=cur_cs;
if u>=hash_base then t:=text(u) else t:="OCP";
define(u,set_ocp,null_ocp); scan_optional_equals; scan_file_name;
@<If this ocp has already been loaded, set |f| to the internal
  ocp number and |goto common_ending|@>;
f:=read_ocp_info(u,cur_name,cur_area,cur_ext,external_ocp);
common_ending:
equiv(u):=f; eqtb[ocp_id_base+f] := eqtb[u];
text(ocp_id_base+f) := t;
if equiv(ocp_trace_level_base)=1 then begin
  print_nl(""); print_esc("ocp"); print_esc(t); print("="); print(cur_name);
  end;
end;

@ When the user gives a new identifier to a ocp that was previously loaded,
the new name becomes the ocp identifier of record. OCP names `\.{xyz}' and
`\.{XYZ}' are considered to be different.

@<If this ocp has already been loaded...@>=
flushable_string:=str_ptr-1;
for f:=ocp_base+1 to ocp_ptr do
  if str_eq_str(ocp_name(f),cur_name)and str_eq_str(ocp_area(f),cur_area) then
    begin
    if cur_name=flushable_string then begin
      flush_string; cur_name:=ocp_name(f);
      end;
    goto common_ending
    end

@ @<Declare subprocedures for |prefixed_command|@>=
procedure new_ocp_list(@!a:small_number);
var u:pointer; {user's ocp list identifier}
@!f:internal_ocp_list_number; {runs through existing ocp lists}
@!t:str_number; {name for the frozen ocp list identifier}
begin if job_name=0 then open_log_file;
  {avoid confusing \.{texput} with the ocp list name}
@.texput@>
get_r_token; u:=cur_cs;
if u>=hash_base then t:=text(u) else t:="OCPLIST";
define(u,set_ocp_list,null_ocp_list); scan_optional_equals;
f:=read_ocp_list;
    equiv(u) := f; eqtb[ocp_list_id_base+f] := eqtb[u];
    text(ocp_list_id_base+f) := t;
if equiv(ocp_trace_level_base)=1 then begin
  print_nl(""); print_esc("ocplist"); print_esc(t); print("=");
  print_ocp_list(ocp_list_list[f]);
  end;
end;

@ @<Declare subprocedures for |prefixed_command|@>=
procedure do_push_ocp_list(@!a:small_number);
var ocp_list_no:halfword;
    old_number:halfword;
    i:integer;
begin
scan_ocp_list_ident; ocp_list_no:=cur_val;
old_number:=equiv(ocp_active_number_base);
define(ocp_active_base+old_number, data, ocp_list_no);
define(ocp_active_number_base, data, (old_number+1));

if equiv(ocp_trace_level_base)=1 then begin
  print_nl("New active ocp list: {");
  for i:=old_number downto 0 do begin
    print_esc(ocp_list_id_text(equiv(ocp_active_base+i)));
    print("="); print_ocp_list(ocp_list_list[equiv(ocp_active_base+i)]);
    if i<>0 then print(",");
    end;
  print("}");
  end;

active_compile;
define(ocp_active_min_ptr_base, data, active_min_ptr);
define(ocp_active_max_ptr_base, data, active_max_ptr);
end;

@ @<Declare subprocedures for |prefixed_command|@>=
procedure do_pop_ocp_list(@!a:small_number);
var old_number:halfword;
    i:integer;
begin
old_number:=equiv(ocp_active_number_base);
if old_number=0 then begin
  print_err("No active ocp lists to be popped");
  end
else
  define(ocp_active_number_base, data, (old_number-1));

if equiv(ocp_trace_level_base)=1 then begin
  print_nl("New active ocp list: {");
  for i:=(old_number-2) downto 0 do begin
    print_esc(ocp_list_id_text(equiv(ocp_active_base+i)));
    print("="); print_ocp_list(ocp_list_list[equiv(ocp_active_base+i)]);
    if i<>0 then print(",");
    end;
  print("}");
  end;

active_compile;
define(ocp_active_min_ptr_base, data, active_min_ptr);
define(ocp_active_max_ptr_base, data, active_max_ptr);
end;

@ @<Declare subprocedures for |prefixed_command|@>=
procedure do_clear_ocp_lists(@!a:small_number);
begin
define(ocp_active_number_base, data, 0);
active_compile;
define(ocp_active_min_ptr_base, data, active_min_ptr);
define(ocp_active_max_ptr_base, data, active_max_ptr);
end;


@* \[54/SyncTeX] The {\sl Synchronize \TeX nology}.
This section is devoted to the {\sl Synchronize \TeX nology}
- or simply {\sl Sync\TeX} - used to synchronize between input and output.
This section explains how synchronization basics are implemented.
Before we enter into more technical details,
let us recall in a few words what is synchronization.

\TeX\ typesetting system clearly separates the input and the output material,
and synchronization will provide a new link between both that can help
text editors and viewers to work together.
More precisely, forwards synchronization is the ability,
given a location in the input source file,
to find what is the corresponding place in the output.
Backwards synchronization just performs the opposite:
given a location in the output,
retrieve the corresponding material in the input source file.

For better code management and maintainance, we adopt a naming convention.
Throughout this program, code related to the {\sl Synchronize \TeX nology} is tagged
with the ``{\sl synctex}'' key word. Any code extract where {\sl Sync\TeX} plays
its part, either explicitly or implicitly, (should) contain the string ``{\sl synctex}''.
This naming convention also holds for external files.
Moreover, all the code related to {\sl Sync\TeX} is gathered in this section,
except the definitions.

@ Enabling synchronization should be performed from the command line,
|synctexoption| is used for that purpose.
This global integer variable is declared here but it is not used here.
This is just a placeholder where the command line controller will put
the {\sl Sync\TeX} related options, and the {\sl Sync\TeX} controller will read them.

@ @<Glob...@>=
@!synctexoption:integer;

@ A convenient primitive is provided:
\.{\\synctex=1} in the input source file enables synchronization whereas
\.{\\synctex=0} disables it.
Its memory address is |synctex_code|.
It is initialized by the {\sl Sync\TeX} controller to the command-line option if given.
The controller may filter some reserved bits.

@ In order to give the {\sl Sync\TeX} controller read and write access to
the contents of the \.{\\synctex} primitive, we declare |synctexoffset|,
such that |mem[synctexoffset]| and \.{\\synctex} correspond to
the same memory storage. |synctexoffset| is initialized to
the correct value when quite everything is initialized.

@ @<Glob...@>=
@!synctexoffset:integer; {holds the true value of |synctex_code|}

@ @<Initialize whatever...@>=
synctexoffset:=int_base+synctex_code;

@ @<Initialize synctex primitive@>=
synctex_init_command;

@ Synchronization is achieved with the help of an auxiliary file named
`\.{{\sl jobname}.synctex}' ({\sl jobname} is the contents of the
\.{\\jobname} macro), where a {\sl Sync\TeX} controller implemented
in the external |synctex.c| file will store geometrical information.
This {\sl Sync\TeX} controller will take care of every technical details
concerning the {\sl Sync\TeX} file, we will only focus on the messages
the controller will receive from the \TeX\ program.

The most accurate synchronization information should allow to map
any character of the input source file to the corresponding location
in the output, if relevant.
Ideally, the synchronization information of the input material consists of
the file name, the line and column numbers of every character.
The synchronization information in the output is simply the page number and
either point coordinates, or box dimensions and position.
The problem is that the mapping between these informations is only known at
ship out time, which means that we must keep track of the input
synchronization information until the pages ship out.

As \TeX\ only knows about file names and line numbers,
but forgets the column numbers, we only consider a
restricted input synchronization information called {\sl Sync\TeX\ information}.
It consists of a unique file name identifier, the {\sl Sync\TeX\ file tag},
and the line number.

Keeping track of such information,
should be different whether characters or nodes are involved.
Actually, only certain nodes are involved in {\sl Sync\TeX},
we call them {\sl synchronized nodes}.
Synchronized nodes store the {\sl Sync\TeX} information in their last two words:
the first one contains a {\sl Sync\TeX\ file tag} uniquely identifying
the input file, and the second one contains the current line number,
as returned by the \.{\\inputlineno} primitive.
The |synctex_field_size| macro contains the necessary size to store
the {\sl Sync\TeX} information in a node.

When declaring the size of a new node, it is recommanded to use the following
convention: if the node is synchronized, use a definition similar to
|my_synchronized_node_size|={\sl xxx}+|synctex_field_size|.
Moreover, one should expect that the {\sl Sync\TeX} information is always stored
in the last two words of a synchronized node.

@ By default, every node with a sufficiently big size is initialized
at creation time in the |get_node| routine with the current
{\sl Sync\TeX} information, whether or not the node is synchronized.
One purpose is to set this information very early in order to minimize code
dependencies, including forthcoming extensions.
Another purpose is to avoid the assumption that every node type has a dedicated getter,
where initialization should take place. Actually, it appears that some nodes are created
using directly the |get_node| routine and not the dedicated constructor.
And finally, initializing the node at only one place is less error prone.

@ Instead of storing the input file name, it is better to store just an identifier.
Each time \TeX\ opens a new file, it notifies the {\sl Sync\TeX} controller with
a |synctex_start_input| message.
This controller will create a new {\sl Sync\TeX} file tag and
will update the current input state record accordingly.
If the input comes from the terminal or a pseudo file, the |synctex_tag| is set to 0.
It results in automatically disabling synchronization for material
input from the terminal or pseudo files.

@ @<Prepare new file {\sl Sync\TeX} information@>=
synctex_start_input; {Give control to the {\sl Sync\TeX} controller}

@ @<Prepare terminal input {\sl Sync\TeX} information@>=
synctex_tag:=0;

@ @<Prepare pseudo file {\sl Sync\TeX} information@>=
synctex_tag:=0;

@ @<Close {\sl Sync\TeX} file and write status@>=
synctex_terminate(log_opened); {Let the {\sl Sync\TeX} controller close its files.}

@ Synchronized nodes are boxes, math, kern and glue nodes.
Other nodes should be synchronized too, in particular math noads.
\TeX\ assumes that math, kern and glue nodes have the same size,
this is why both are synchronized.
{\sl In fine}, only horizontal lists are really used in {\sl Sync\TeX},
but all box nodes are considered the same with respect to synchronization,
because a box node type is allowed to change at execution time.

The next sections are the various messages sent to the {\sl Sync\TeX} controller.
The argument is either the box or the node currently shipped out.
The vertical boxes are not recorded, but the code is available for clients.

@ @<Start sheet {\sl Sync\TeX} information record@>=
pdf_output_value:=pdf_output; {{\sl Sync\TeX}: we assume that |pdf_output| is properly set up}
synctex_sheet(mag);

@ @<Finish sheet {\sl Sync\TeX} information record@>=
synctex_teehs;

@ @<Start vlist {\sl Sync\TeX} information record@>=
synctex_vlist(this_box);

@ @<Finish vlist {\sl Sync\TeX} information record@>=
synctex_tsilv(this_box);

@ @<Start hlist {\sl Sync\TeX} information record@>=
synctex_hlist(this_box);

@ @<Finish hlist {\sl Sync\TeX} information record@>=
synctex_tsilh(this_box);

@ @<Record void list {\sl Sync\TeX} information@>=
  if type(p)=vlist_node then begin
      synctex_void_vlist(p,this_box);
    end
  else begin
      synctex_void_hlist(p,this_box);
    end;

@ @<Record current point {\sl Sync\TeX} information@>=
synctex_current;

@ @<Record horizontal |rule_node| or |glue_node| {\sl Sync\TeX} information@>=
synctex_horizontal_rule_or_glue(p,this_box);

@ @<Record |kern_node| {\sl Sync\TeX} information@>=
synctex_kern(p,this_box);

@ @<Record |math_node| {\sl Sync\TeX} information@>=
synctex_math(p,this_box);


@ {\sl Nota Bene:}
The {\sl Sync\TeX} code is very close to the memory model.
It is not connected to any other part of the code,
except for memory management. It is possible to neutralize the {\sl Sync\TeX} code
rather simply. The first step is to define a null |synctex_field_size|.
The second step is to comment out the code in ``Initialize bigger nodes...'' and every
``Copy ... {\sl Sync\TeX} information''.
The last step will be to comment out the |synctex_tag_field| related code in the
definition of |synctex_tag| and the various ``Prepare ... {\sl Sync\TeX} information''.
Then all the remaining code should be just harmless.
The resulting program would behave exactly the same as if absolutely no {\sl Sync\TeX}
related code was there, including memory management.
Of course, all this assumes that {\sl Sync\TeX} is turned off from the command line.
@^synctex@>
@^synchronization@>

@* \[54] System-dependent changes.
This section should be replaced, if necessary, by any special
modifications of the program
that are necessary to make \TeX\ work at a particular installation.
It is usually best to design your change file so that all changes to
previous sections preserve the section numbering; then everybody's version
will be consistent with the published program. More extensive changes,
which introduce new sections, can be inserted here; then only the index
itself will get a new section number.
@^system dependencies@>

@* \[55] Index.
Here is where you can find all uses of each identifier in the program,
with underlined entries pointing to where the identifier was defined.
If the identifier is only one letter long, however, you get to see only
the underlined entries. {\sl All references are to section numbers instead of
page numbers.}

This index also lists error messages and other aspects of the program
that you might want to look up some day. For example, the entry
for ``system dependencies'' lists all sections that should receive
special attention from people who are installing \TeX\ in a new
operating environment. A list of various things that can't happen appears
under ``this can't happen''. Approximately 40 sections are listed under
``inner loop''; these account for about 60\pct! of \TeX's running time,
exclusive of input and output.