summaryrefslogtreecommitdiff
path: root/Build/source/texk/web2c/cwebdir/cweave.w
blob: db5b4f250f53898d0392cefe4b1cede65f0a9021 (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
% This file is part of CWEB.
% This program by Silvio Levy and Donald E. Knuth
% is based on a program by Knuth.
% It is distributed WITHOUT ANY WARRANTY, express or implied.
% Version 4.5 --- July 2021

% Copyright (C) 1987,1990,1993,2000 Silvio Levy and Donald E. Knuth

% Permission is granted to make and distribute verbatim copies of this
% document provided that the copyright notice and this permission notice
% are preserved on all copies.

% Permission is granted to copy and distribute modified versions of this
% document under the conditions for verbatim copying, provided that the
% entire resulting derived work is given a different name and distributed
% under the terms of a permission notice identical to this one.

% Amendments to 'cweave.w' resulting in this updated version were created
% by numerous collaborators over the course of many years.

% Please send comments, suggestions, etc. to tex-k@@tug.org.

% Here is TeX material that gets inserted after \input cwebmac
\def\hang{\hangindent 3em\indent\ignorespaces}
\def\pb{$\.|\ldots\.|$} % C brackets (|...|)
\def\v{\char'174} % vertical (|) in typewriter font
\def\dleft{[\![} \def\dright{]\!]} % double brackets
\mathchardef\RA="3221 % right arrow
\mathchardef\BA="3224 % double arrow
\def\({} % ) kludge for alphabetizing certain section names
\def\TeXxstring{\\{\TEX/\_string}}
\def\skipxTeX{\\{skip\_\TEX/}}
\def\copyxTeX{\\{copy\_\TEX/}}

\def\title{CWEAVE (Version 4.5)}
\def\topofcontents{\null\vfill
  \centerline{\titlefont The {\ttitlefont CWEAVE} processor}
  \vskip 15pt
  \centerline{(Version 4.5)}
  \vfill}
\def\botofcontents{\vfill
\noindent
Copyright \copyright\ 1987, 1990, 1993, 2000 Silvio Levy and Donald E. Knuth
\bigskip\noindent
Permission is granted to make and distribute verbatim copies of this
document provided that the copyright notice and this permission notice
are preserved on all copies.

\smallskip\noindent
Permission is granted to copy and distribute modified versions of this
document under the conditions for verbatim copying, provided that the
entire resulting derived work is given a different name and distributed
under the terms of a permission notice identical to this one.
}
\pageno=\contentspagenumber \advance\pageno by 1
\let\maybe=\iftrue

@** Introduction.
This is the \.{CWEAVE} program by Silvio Levy and Donald E. Knuth,
based on \.{WEAVE} by Knuth.
We are thankful to Steve Avery,
Nelson Beebe, Hans-Hermann Bode (to whom the original \CPLUSPLUS/ adaptation
is due), Klaus Guntermann, Norman Ramsey, Tomas Rokicki, Joachim Schnitter,
Joachim Schrod, Lee Wittenberg, Saroj Mahapatra, Cesar Augusto Rorato
Crusius, and others who have contributed improvements.

The ``banner line'' defined here should be changed whenever \.{CWEAVE}
is modified.

@d banner "This is CWEAVE (Version 4.5)"

@c
@<Include files@>@/
@h
@<Common code for \.{CWEAVE} and \.{CTANGLE}@>@/
@<Typedef declarations@>@/
@<Private variables@>@/
@<Predeclaration of procedures@>

@ \.{CWEAVE} has a fairly straightforward outline.  It operates in
three phases: First it inputs the source file and stores cross-reference
data, then it inputs the source once again and produces the \TEX/ output
file, finally it sorts and outputs the index.

Please read the documentation for \.{common}, the set of routines common
to \.{CTANGLE} and \.{CWEAVE}, before proceeding further.

@c
int main (
int ac, /* argument count */
char **av) /* argument values */
{
  argc=ac; argv=av;
  program=cweave;
  @<Set initial values@>@;
  common_init();
  @<Start \TEX/ output@>@;
  if (show_banner) puts(banner); /* print a ``banner line'' */
  @<Store all the reserved words@>@;
  phase_one(); /* read all the user's text and store the cross-references */
  phase_two(); /* read all the text again and translate it to \TEX/ form */
  phase_three(); /* output the cross-reference index */
  if (tracing==fully && !show_progress) new_line;
  return wrap_up(); /* and exit gracefully */
}

@ The next few sections contain stuff from the file |"common.w"| that must
be included in both |"ctangle.w"| and |"cweave.w"|. It appears in
file |"common.h"|, which is also included in |"common.w"| to propagate
possible changes from this \.{COMMON} interface consistently.

@i common.h

@ The following parameters were sufficient in the original \.{WEAVE} to
handle \TEX/, so they should be sufficient for most applications of \.{CWEAVE}.

@d line_length 80 /* lines of \TEX/ output have at most this many characters;
  should be less than 256 */
@d max_refs 20000 /* number of cross-references; must be less than 65536 */
@d max_scraps 2000 /* number of tokens in \CEE/ texts being parsed */

@* Data structures exclusive to {\tt CWEAVE}.
As explained in \.{common.w}, the field of a |name_info| structure
that contains the |rlink| of a section name is used for a completely
different purpose in the case of identifiers.  It is then called the
|ilk| of the identifier, and it is used to
distinguish between various types of identifiers, as follows:

\yskip\hang |normal| and |func_template| identifiers are part of the
\CEE/ program that will  appear in italic type (or in typewriter type
if all uppercase).

\yskip\hang |custom| identifiers are part of the \CEE/ program that
will be typeset in special ways.

\yskip\hang |roman| identifiers are index entries that appear after
\.{@@\^} in the \.{CWEB} file.

\yskip\hang |wildcard| identifiers are index entries that appear after
\.{@@:} in the \.{CWEB} file.

\yskip\hang |typewriter| identifiers are index entries that appear after
\.{@@.} in the \.{CWEB} file.

\yskip\hang |alfop|, \dots, |attr|
identifiers are \CEE/ or \CPLUSPLUS/ reserved words whose |ilk|
explains how they are to be treated when \CEE/ code is being
formatted.

@d ilk dummy.Ilk
@d normal 0 /* ordinary identifiers have |normal| ilk */
@d roman 1 /* normal index entries have |roman| ilk */
@d wildcard 2 /* user-formatted index entries have |wildcard| ilk */
@d typewriter 3 /* `typewriter type' entries have |typewriter| ilk */
@d abnormal(a) ((a)->ilk>typewriter) /* tells if a name is special */
@d func_template 4 /* identifiers that can be followed by optional template */
@d custom 5 /* identifiers with user-given control sequence */
@d alfop 22 /* alphabetic operators like \&{and} or \&{not\_eq} */
@d else_like 26 /* \&{else} */
@d public_like 40 /* \&{public}, \&{private}, \&{protected} */
@d operator_like 41 /* \&{operator} */
@d new_like 42 /* \&{new} */
@d catch_like 43 /* \&{catch} */
@d for_like 45 /* \&{for}, \&{switch}, \&{while} */
@d do_like 46 /* \&{do} */
@d if_like 47 /* \&{if}, \&{ifdef}, \&{endif}, \&{pragma}, \dots */
@d delete_like 48 /* \&{delete} */
@d raw_ubin 49 /* `\.\&' or `\.*' when looking for \&{const} following */
@d const_like 50 /* \&{const}, \&{volatile} */
@d raw_int 51 /* \&{int}, \&{char}, \dots; also structure and class names */
@d int_like 52 /* same, when not followed by left parenthesis or \DC\ */
@d case_like 53 /* \&{case}, \&{return}, \&{goto}, \&{break}, \&{continue} */
@d sizeof_like 54 /* \&{sizeof} */
@d struct_like 55 /* \&{struct}, \&{union}, \&{enum}, \&{class} */
@d typedef_like 56 /* \&{typedef} */
@d define_like 57 /* \&{define} */
@d template_like 58 /* \&{template} */
@d alignas_like 59 /* \&{alignas} */
@d using_like 60 /* \&{using} */
@d default_like 61 /* \&{default} */
@d attr 62 /* \&{noexcept} and attributes */

@ We keep track of the current section number in |section_count|, which
is the total number of sections that have started.  Sections which have
been altered by a change file entry have their |changed_section| flag
turned on during the first phase.

@<Private...@>=
static boolean change_exists; /* has any section changed? */

@ The other large memory area in \.{CWEAVE} keeps the cross-reference data.
All uses of the name |p| are recorded in a linked list beginning at
|p->xref|, which points into the |xmem| array. The elements of |xmem|
are structures consisting of an integer, |num|, and a pointer |xlink|
to another element of |xmem|.  If |x=p->xref| is a pointer into |xmem|,
the value of |x->num| is either a section number where |p| is used,
or |cite_flag| plus a section number where |p| is mentioned,
or |def_flag| plus a section number where |p| is defined;
and |x->xlink| points to the next such cross-reference for |p|,
if any. This list of cross-references is in decreasing order by
section number. The next unused slot in |xmem| is |xref_ptr|.
The linked list ends at |&xmem[0]|.

The global variable |xref_switch| is set either to |def_flag| or to zero,
depending on whether the next cross-reference to an identifier is to be
underlined or not in the index. This switch is set to |def_flag| when
\.{@@!} or \.{@@d} is scanned, and it is cleared to zero when
the next identifier or index entry cross-reference has been made.
Similarly, the global variable |section_xref_switch| is either
|def_flag| or |cite_flag| or zero, depending
on whether a section name is being defined, cited or used in \CEE/ text.

@<Type...@>=
typedef struct xref_info {
  sixteen_bits num; /* section number plus zero or |def_flag| */
  struct xref_info *xlink; /* pointer to the previous cross-reference */
} xref_info;
typedef xref_info *xref_pointer;

@ @<Private...@>=
static xref_info xmem[max_refs]; /* contains cross-reference information */
static xref_pointer xmem_end = xmem+max_refs-1;
static xref_pointer xref_ptr; /* the largest occupied position in |xmem| */
static sixteen_bits xref_switch,section_xref_switch; /* either zero or |def_flag| */

@ A section that is used for multi-file output (with the \.{@@(} feature)
has a special first cross-reference whose |num| field is |file_flag|.

@d file_flag (3*cite_flag)
@d def_flag (2*cite_flag)
@d cite_flag 10240 /* must be strictly larger than |max_sections| */
@d xref equiv_or_xref

@<Set init...@>=
xref_ptr=xmem; init_node(name_dir); xref_switch=section_xref_switch=0;
xmem->num=0; /* sentinel value */

@ A new cross-reference for an identifier is formed by calling |new_xref|,
which discards duplicate entries and ignores non-underlined references
to one-letter identifiers or \CEE/'s reserved words.

If the user has sent the |no_xref| flag (the \.{-x} option of the command line),
it is unnecessary to keep track of cross-references for identifiers.
If one were careful, one could probably make more changes around section
115 to avoid a lot of identifier looking up.

@d append_xref(c) if (xref_ptr==xmem_end) overflow("cross-reference");
  else (++xref_ptr)->num=c
@d no_xref !make_xrefs
@d is_tiny(p) length(p)==1
@d unindexed(a) ((a)<res_wd_end && (a)->ilk>=custom)
      /* tells if uses of a name are to be indexed */

@<Predecl...@>=
static void new_xref(name_pointer);@/
static void new_section_xref(name_pointer);@/
static void set_file_flag(name_pointer);

@ @c
static void
new_xref(
name_pointer p)
{
  xref_pointer q; /* pointer to previous cross-reference */
  sixteen_bits m, n; /* new and previous cross-reference value */
  if (no_xref) return;
  if ((unindexed(p) || is_tiny(p)) && xref_switch==0) return;
  m=section_count+xref_switch; xref_switch=0; q=(xref_pointer)p->xref;
  if (q != xmem) {
    n=q->num;
    if (n==m || n==m+def_flag) return;
    else if (m==n+def_flag) {
        q->num=m; return;
    }
  }
  append_xref(m); xref_ptr->xlink=q; update_node(p);
}

@ The cross-reference lists for section names are slightly different.
Suppose that a section name is defined in sections $m_1$, \dots,
$m_k$, cited in sections $n_1$, \dots, $n_l$, and used in sections
$p_1$, \dots, $p_j$.  Then its list will contain $m_1+|def_flag|$,
\dots, $m_k+|def_flag|$, $n_1+|cite_flag|$, \dots,
$n_l+|cite_flag|$, $p_1$, \dots, $p_j$, in this order.

Although this method of storage takes quadratic time with respect to
the length of the list, under foreseeable uses of \.{CWEAVE} this inefficiency
is insignificant.

@c
static void
new_section_xref(
name_pointer p)
{
  xref_pointer q=(xref_pointer)p->xref;
  xref_pointer r=xmem; /* pointers to previous cross-references */
  if (q>r)
        while (q->num>section_xref_switch) {r=q; q=q->xlink;}
  if (r->num==section_count+section_xref_switch)
        return; /* don't duplicate entries */
  append_xref(section_count+section_xref_switch);
  xref_ptr->xlink=q; section_xref_switch=0;
  if (r==xmem) update_node(p);
  else r->xlink=xref_ptr;
}

@ The cross-reference list for a section name may also begin with
|file_flag|. Here's how that flag gets put~in.

@c
static void
set_file_flag(
name_pointer p)
{
  xref_pointer q=(xref_pointer)p->xref;
  if (q->num==file_flag) return;
  append_xref(file_flag);
  xref_ptr->xlink = q;
  update_node(p);
}

@ A third large area of memory is used for sixteen-bit `tokens', which appear
in short lists similar to the strings of characters in |byte_mem|. Token lists
are used to contain the result of \CEE/ code translated into \TEX/ form;
further details about them will be explained later. A \&{text\_pointer}
variable is an index into |tok_start|.

@<Typed...@>=
typedef sixteen_bits token;
typedef token *token_pointer;
typedef token_pointer *text_pointer;

@ The first position of |tok_mem|
that is unoccupied by replacement text is called |tok_ptr|, and the first
unused location of |tok_start| is called |text_ptr|.
Thus, we usually have |*text_ptr==tok_ptr|.

@d max_toks 20000 /* number of symbols in \CEE/ texts being parsed;
  must be less than 65536 */
@d max_texts 4000 /* number of phrases in \CEE/ texts being parsed;
  must be less than 10240 */

@<Private...@>=
static token tok_mem[max_toks]; /* tokens */
static token_pointer tok_mem_end = tok_mem+max_toks-1; /* end of |tok_mem| */
static token_pointer tok_ptr; /* first unused position in |tok_mem| */
static token_pointer max_tok_ptr; /* largest value of |tok_ptr| */
static token_pointer tok_start[max_texts]; /* directory into |tok_mem| */
static text_pointer tok_start_end = tok_start+max_texts-1; /* end of |tok_start| */
static text_pointer text_ptr; /* first unused position in |tok_start| */
static text_pointer max_text_ptr; /* largest value of |text_ptr| */

@ @<Set init...@>=
tok_ptr=max_tok_ptr=tok_mem+1;@/
tok_start[0]=tok_start[1]=tok_mem+1;@/
text_ptr=max_text_ptr=tok_start+1;

@ Here are the three procedures needed to complete |id_lookup|:
@c
boolean names_match(
name_pointer p, /* points to the proposed match */
const char *first, /* position of first character of string */
size_t l, /* length of identifier */
eight_bits t) /* desired |ilk| */
{
  if (length(p)!=l) return false;
  if (p->ilk!=t && !(t==normal && abnormal(p))) return false;
  return !strncmp(first,p->byte_start,l);
}

void
init_p(
name_pointer p,
eight_bits t)
{
  p->ilk=t; init_node(p);
}

void
init_node(
name_pointer p)
{
  p->xref=(void *)xmem;
}

@ And here's a small helper function to simplify the code.

@d update_node(p) (p)->xref=(void *)xref_ptr

@ We have to get \CEE/'s and \CPLUSPLUS/'s
reserved words into the hash table, and the simplest way to do this is
to insert them every time \.{CWEAVE} is run.  Fortunately there are relatively
few reserved words. (Some of these are not strictly ``reserved,'' but
are defined in header files of the ISO Standard \CEE/ Library.
An ever growing list of \CPLUSPLUS/ keywords can be found here:
\.{https://en.cppreference.com/w/cpp/keyword}.)
@^reserved words@>

@<Store all the reserved words@>=
id_lookup("alignas",NULL,alignas_like);
id_lookup("alignof",NULL,sizeof_like);
id_lookup("and",NULL,alfop);
id_lookup("and_eq",NULL,alfop);
id_lookup("asm",NULL,sizeof_like);
id_lookup("auto",NULL,int_like);
id_lookup("bitand",NULL,alfop);
id_lookup("bitor",NULL,alfop);
id_lookup("bool",NULL,raw_int);
id_lookup("break",NULL,case_like);
id_lookup("case",NULL,case_like);
id_lookup("catch",NULL,catch_like);
id_lookup("char",NULL,raw_int);
id_lookup("char8_t",NULL,raw_int);
id_lookup("char16_t",NULL,raw_int);
id_lookup("char32_t",NULL,raw_int);
id_lookup("class",NULL,struct_like);
id_lookup("clock_t",NULL,raw_int);
id_lookup("compl",NULL,alfop);
id_lookup("concept",NULL,int_like);
id_lookup("const",NULL,const_like);
id_lookup("consteval",NULL,const_like);
id_lookup("constexpr",NULL,const_like);
id_lookup("constinit",NULL,const_like);
id_lookup("const_cast",NULL,raw_int);
id_lookup("continue",NULL,case_like);
id_lookup("co_await",NULL,case_like);
id_lookup("co_return",NULL,case_like);
id_lookup("co_yield",NULL,case_like);
id_lookup("decltype",NULL,sizeof_like);
id_lookup("default",NULL,default_like);
id_lookup("define",NULL,define_like);
id_lookup("defined",NULL,sizeof_like);
id_lookup("delete",NULL,delete_like);
id_lookup("div_t",NULL,raw_int);
id_lookup("do",NULL,do_like);
id_lookup("double",NULL,raw_int);
id_lookup("dynamic_cast",NULL,raw_int);
id_lookup("elif",NULL,if_like);
id_lookup("else",NULL,else_like);
id_lookup("endif",NULL,if_like);
id_lookup("enum",NULL,struct_like);
id_lookup("error",NULL,if_like);
id_lookup("explicit",NULL,int_like);
id_lookup("export",NULL,int_like);
id_lookup("extern",NULL,int_like);
id_lookup("FILE",NULL,raw_int);
id_lookup("false",NULL,normal);
id_lookup("float",NULL,raw_int);
id_lookup("for",NULL,for_like);
id_lookup("fpos_t",NULL,raw_int);
id_lookup("friend",NULL,int_like);
id_lookup("goto",NULL,case_like);
id_lookup("if",NULL,if_like);
id_lookup("ifdef",NULL,if_like);
id_lookup("ifndef",NULL,if_like);
id_lookup("include",NULL,if_like);
id_lookup("inline",NULL,int_like);
id_lookup("int",NULL,raw_int);
id_lookup("jmp_buf",NULL,raw_int);
id_lookup("ldiv_t",NULL,raw_int);
id_lookup("line",NULL,if_like);
id_lookup("long",NULL,raw_int);
id_lookup("mutable",NULL,int_like);
id_lookup("namespace",NULL,struct_like);
id_lookup("new",NULL,new_like);
id_lookup("noexcept",NULL,attr);
id_lookup("not",NULL,alfop);
id_lookup("not_eq",NULL,alfop);
id_lookup("NULL",NULL,custom);
id_lookup("nullptr",NULL,custom);
id_lookup("offsetof",NULL,raw_int);
id_lookup("operator",NULL,operator_like);
id_lookup("or",NULL,alfop);
id_lookup("or_eq",NULL,alfop);
id_lookup("pragma",NULL,if_like);
id_lookup("private",NULL,public_like);
id_lookup("protected",NULL,public_like);
id_lookup("ptrdiff_t",NULL,raw_int);
id_lookup("public",NULL,public_like);
id_lookup("register",NULL,int_like);
id_lookup("reinterpret_cast",NULL,raw_int);
id_lookup("requires",NULL,int_like);
id_lookup("restrict",NULL,int_like);
id_lookup("return",NULL,case_like);
id_lookup("short",NULL,raw_int);
id_lookup("sig_atomic_t",NULL,raw_int);
id_lookup("signed",NULL,raw_int);
id_lookup("size_t",NULL,raw_int);
id_lookup("sizeof",NULL,sizeof_like);
id_lookup("static",NULL,int_like);
id_lookup("static_assert",NULL,sizeof_like);
id_lookup("static_cast",NULL,raw_int);
id_lookup("struct",NULL,struct_like);
id_lookup("switch",NULL,for_like);
id_lookup("template",NULL,template_like);
id_lookup("this",NULL,custom);
id_lookup("thread_local",NULL,raw_int);
id_lookup("throw",NULL,case_like);
id_lookup("time_t",NULL,raw_int);
id_lookup("true",NULL,normal);
id_lookup("try",NULL,else_like);
id_lookup("typedef",NULL,typedef_like);
id_lookup("typeid",NULL,sizeof_like);
id_lookup("typename",NULL,struct_like);
id_lookup("undef",NULL,if_like);
id_lookup("union",NULL,struct_like);
id_lookup("unsigned",NULL,raw_int);
id_lookup("using",NULL,using_like);@/
id_lookup("va_dcl",NULL,decl); /* Berkeley's variable-arg-list convention */
id_lookup("va_list",NULL,raw_int); /* ditto */
id_lookup("virtual",NULL,int_like);
id_lookup("void",NULL,raw_int);
id_lookup("volatile",NULL,const_like);
id_lookup("wchar_t",NULL,raw_int);
id_lookup("while",NULL,for_like);
id_lookup("xor",NULL,alfop);
id_lookup("xor_eq",NULL,alfop);@+ res_wd_end=name_ptr;
id_lookup("TeX",NULL,custom);
id_lookup("complex",NULL,int_like);
id_lookup("imaginary",NULL,int_like);
id_lookup("make_pair",NULL,func_template);

@* Lexical scanning.
Let us now consider the subroutines that read the \.{CWEB} source file
and break it into meaningful units. There are four such procedures:
One simply skips to the next `\.{@@\ }' or `\.{@@*}' that begins a
section; another passes over the \TEX/ text at the beginning of a
section; the third passes over the \TEX/ text in a \CEE/ comment;
and the last, which is the most interesting, gets the next token of
a \CEE/ text.  They all use the pointers |limit| and |loc| into
the line of input currently being studied.

@ Control codes in \.{CWEB}, which begin with `\.{@@}', are converted
into a numeric code designed to simplify \.{CWEAVE}'s logic; for example,
larger numbers are given to the control codes that denote more significant
milestones, and the code of |new_section| should be the largest of
all. Some of these numeric control codes take the place of |char|
control codes that will not otherwise appear in the output of the
scanning routines.
@^ASCII code dependencies@>

@d ignore 00 /* control code of no interest to \.{CWEAVE} */
@d verbatim 02 /* takes the place of ASCII \.{STX} */
@d begin_short_comment 03 /* \CPLUSPLUS/ short comment */
@d begin_comment '\t' /* tab marks will not appear */
@d underline '\n' /* this code will be intercepted without confusion */
@d noop 0177 /* takes the place of ASCII \.{DEL} */
@d xref_roman 0203 /* control code for `\.{@@\^}' */
@d xref_wildcard 0204 /* control code for `\.{@@:}' */
@d xref_typewriter 0205 /* control code for `\.{@@.}' */
@d TeX_string 0206 /* control code for `\.{@@t}' */
@f TeX_string TeX
@d ord 0207 /* control code for `\.{@@'}' */
@d join 0210 /* control code for `\.{@@\&}' */
@d thin_space 0211 /* control code for `\.{@@,}' */
@d math_break 0212 /* control code for `\.{@@\v}' */
@d line_break 0213 /* control code for `\.{@@/}' */
@d big_line_break 0214 /* control code for `\.{@@\#}' */
@d no_line_break 0215 /* control code for `\.{@@+}' */
@d pseudo_semi 0216 /* control code for `\.{@@;}' */
@d macro_arg_open 0220 /* control code for `\.{@@[}' */
@d macro_arg_close 0221 /* control code for `\.{@@]}' */
@d trace 0222 /* control code for `\.{@@0}', `\.{@@1}' and `\.{@@2}' */
@d translit_code 0223 /* control code for `\.{@@l}' */
@d output_defs_code 0224 /* control code for `\.{@@h}' */
@d format_code 0225 /* control code for `\.{@@f}' and `\.{@@s}' */
@d definition 0226 /* control code for `\.{@@d}' */
@d begin_C 0227 /* control code for `\.{@@c}' */
@d section_name 0230 /* control code for `\.{@@<}' */
@d new_section 0231 /* control code for `\.{@@\ }' and `\.{@@*}' */

@ Control codes are converted to \.{CWEAVE}'s internal
representation by means of the table |ccode|.

@<Private...@>=
static eight_bits ccode[256]; /* meaning of a char following \.{@@} */

@ @<Set ini...@>= {
  int c; /* must be |int| so the |for| loop will end */
  for (c=0; c<256; c++) ccode[c]=ignore;
}
ccode[' ']=ccode['\t']=ccode['\n']=ccode['\v']=ccode['\r']=ccode['\f']
  =ccode['*']=new_section;
ccode['@@']='@@'; /* `quoted' at sign */
ccode['=']=verbatim;
ccode['d']=ccode['D']=definition;
ccode['f']=ccode['F']=ccode['s']=ccode['S']=format_code;
ccode['c']=ccode['C']=ccode['p']=ccode['P']=begin_C;
ccode['t']=ccode['T']=TeX_string;
ccode['l']=ccode['L']=translit_code;
ccode['q']=ccode['Q']=noop;
ccode['h']=ccode['H']=output_defs_code;
ccode['&']=join; ccode['<']=ccode['(']=section_name;
ccode['!']=underline; ccode['^']=xref_roman;
ccode[':']=xref_wildcard; ccode['.']=xref_typewriter; ccode[',']=thin_space;
ccode['|']=math_break; ccode['/']=line_break; ccode['#']=big_line_break;
ccode['+']=no_line_break; ccode[';']=pseudo_semi;
ccode['[']=macro_arg_open; ccode[']']=macro_arg_close;
ccode['\'']=ord;
@<Special control codes for debugging@>@;

@ Users can write
\.{@@2}, \.{@@1}, and \.{@@0} to turn tracing fully on, partly on,
and off, respectively.

@<Special control codes...@>=
ccode['0']=ccode['1']=ccode['2']=trace;

@ The |skip_limbo| routine is used on the first pass to skip through
portions of the input that are not in any sections, i.e., that precede
the first section. After this procedure has been called, the value of
|input_has_ended| will tell whether or not a section has actually been found.

There's a complication that we will postpone until later: If the \.{@@s}
operation appears in limbo, we want to use it to adjust the default
interpretation of identifiers.

@<Predec...@>=
static void skip_limbo(void);@/
static eight_bits skip_TeX(void);

@ @c
static void
skip_limbo(void) {
  while(true) {
    if (loc>limit && get_line()==false) return;
    *(limit+1)='@@';
    while (*loc!='@@') loc++; /* look for `\.{@@}', then skip two chars */
    if (loc++ <=limit)
      switch (ccode[(eight_bits)*loc++]) {
      case new_section: return;
      case noop: skip_restricted(); break;
      case format_code: @<Process simple format in limbo@>@;
      }
  }
}

@ The |skip_TeX| routine is used on the first pass to skip through
the \TEX/ code at the beginning of a section. It returns the next
control code or `\.{\v}' found in the input. A |new_section| is
assumed to exist at the very end of the file.

@f skip_TeX TeX

@c
static eight_bits
skip_TeX(void) /* skip past pure \TEX/ code */
{
  while (true) {
    if (loc>limit && get_line()==false) return new_section;
    *(limit+1)='@@';
    while (*loc!='@@' && *loc!='|') loc++;
    if (*loc++ =='|') return (eight_bits)'|';
    if (loc<=limit) return ccode[(eight_bits)*(loc++)];
  }
}

@*1 Inputting the next token.
As stated above, \.{CWEAVE}'s most interesting lexical scanning routine is the
|get_next| function that inputs the next token of \CEE/ input. However,
|get_next| is not especially complicated.

The result of |get_next| is either a |char| code for some special character,
or it is a special code representing a pair of characters (e.g., `\.{!=}'),
or it is the numeric value computed by the |ccode|
table, or it is one of the following special codes:

\yskip\hang |identifier|: In this case the global variables |id_first| and
|id_loc| will have been set to the beginning and ending-plus-one locations
in the buffer, as required by the |id_lookup| routine.

\yskip\hang |string|: The string will have been copied into the array
|section_text|; |id_first| and |id_loc| are set as above (now they are
pointers into |section_text|).

\yskip\hang |constant|: The constant is copied into |section_text|, with
slight modifications; |id_first| and |id_loc| are set.

\yskip\noindent Furthermore, some of the control codes cause
|get_next| to take additional actions:

\yskip\hang |xref_roman|, |xref_wildcard|, |xref_typewriter|, |TeX_string|,
|verbatim|: The values of |id_first| and |id_loc| will have been set to
the beginning and ending-plus-one locations in the buffer.

\yskip\hang |section_name|: In this case the global variable |cur_section| will
point to the |byte_start| entry for the section name that has just been scanned.
The value of |cur_section_char| will be |'('| if the section name was
preceded by \.{@@(} instead of \.{@@<}.

\yskip\noindent If |get_next| sees `\.{@@!}'
it sets |xref_switch| to |def_flag| and goes on to the next token.

@d constant 0200 /* \CEE/ constant */
@d string 0201 /* \CEE/ string */
@d identifier 0202 /* \CEE/ identifier or reserved word */

@<Private...@>=
static name_pointer cur_section; /* name of section just scanned */
static char cur_section_char; /* the character just before that name */

@ As one might expect, |get_next| consists mostly of a big switch
that branches to the various special cases that can arise.

@c
static eight_bits
get_next(void) /* produces the next input token */
{
  eight_bits c; /* the current character */
  while (true) {
    @<Check if we're at the end of a preprocessor command@>@;
    if (loc>limit && get_line()==false) return new_section;
    c=*(loc++);
    if (xisdigit((int)c) || c=='.') @<Get a constant@>@;
    else if (c=='\'' || c=='"'@|
           || ((c=='L' || c=='u' || c=='U')&&(*loc=='\'' || *loc=='"'))@|
           || ((c=='u' && *loc=='8')&&(*(loc+1)=='\'' || *(loc+1)=='"'))@|
           || (c=='<' && sharp_include_line==true))
        @<Get a string@>@;
    else if (isalpha((int)c) || isxalpha(c) || ishigh(c))
      @<Get an identifier@>@;
    else if (c=='@@') @<Get control code and possible section name@>@;
    else if (xisspace(c)) continue; /* ignore spaces and tabs */
    if (c=='#' && loc==buffer+1) @<Raise preprocessor flag@>@;
    mistake: @<Compress two-symbol operator@>@;
    return c;
  }
}

@ @<Predecl...@>=@+static eight_bits get_next(void);

@ Because preprocessor commands do not fit in with the rest of the syntax
of \CEE/,
we have to deal with them separately.  One solution is to enclose such
commands between special markers.  Thus, when a \.\# is seen as the
first character of a line, |get_next| returns a special code
|left_preproc| and raises a flag |preprocessing|.

We can use the same internal code number for |left_preproc| as we do
for |ord|, since |get_next| changes |ord| into a string.

@d left_preproc ord /* begins a preprocessor command */
@d right_preproc 0217 /* ends a preprocessor command */

@<Private...@>=
static boolean preprocessing=false; /* are we scanning a preprocessor command? */

@ @<Raise prep...@>= {
  preprocessing=true;
  @<Check if next token is |include|@>@;
  return left_preproc;
}

@ An additional complication is the freakish use of \.< and \.> to delimit
a file name in lines that start with \.{\#include}.  We must treat this file
name as a string.

@<Private...@>=
static boolean sharp_include_line=false;
  /* are we scanning a \#\&{include} line? */

@ @<Check if next token is |include|@>=
while (loc<=buffer_end-7 && xisspace(*loc)) loc++;
if (loc<=buffer_end-6 && strncmp(loc,"include",7)==0) sharp_include_line=true;

@ When we get to the end of a preprocessor line,
we lower the flag and send a code |right_preproc|, unless
the last character was a \.\\.

@<Check if we're at...@>=
  while (loc==limit-1 && preprocessing && *loc=='\\')
    if (get_line()==false) return new_section; /* still in preprocessor mode */
  if (loc>=limit && preprocessing) {
    preprocessing=sharp_include_line=false;
    return right_preproc;
  }

@ The following code assigns values to the combinations \.{++},
\.{--}, \.{->}, \.{>=}, \.{<=}, \.{==}, \.{<<}, \.{>>}, \.{!=}, %\.{||}
\.{\v\v} and~\.{\&\&}, and to the \CPLUSPLUS/
combinations \.{...}, \.{::}, \.{.*} and \.{->*}.
The compound assignment operators (e.g., \.{+=}) are
treated as separate tokens.

@<Compress tw...@>=
switch(c) {
  case '/': if (*loc=='*') {@+compress(begin_comment);@+}
    else if (*loc=='/') compress(begin_short_comment); break;
  case '+': if (*loc=='+') compress(plus_plus); break;
  case '-': if (*loc=='-') {@+compress(minus_minus);@+}
            else if (*loc=='>') {
              if (*(loc+1)=='*') {loc++;@+compress(minus_gt_ast);}
              else compress(minus_gt);
            } break;
  case '.': if (*loc=='*') {@+compress(period_ast);@+}
            else if (*loc=='.' && *(loc+1)=='.') {
              loc++;@+compress(dot_dot_dot);
            } break;
  case ':': if (*loc==':') compress(colon_colon); break;
  case '=': if (*loc=='=') compress(eq_eq); break;
  case '>': if (*loc=='=') {@+compress(gt_eq);@+}
    else if (*loc=='>') compress(gt_gt); break;
  case '<': if (*loc=='=') {@+compress(lt_eq);@+}
    else if (*loc=='<') compress(lt_lt); break;
  case '&': if (*loc=='&') compress(and_and); break;
  case '|': if (*loc=='|') compress(or_or); break;
  case '!': if (*loc=='=') compress(non_eq); break;
}

@ @<Get an identifier@>= {
  id_first=--loc;
  do
    ++loc;
  while (isalpha((int)*loc) || isdigit((int)*loc) @|
      || isxalpha(*loc) || ishigh(*loc));
  id_loc=loc; return identifier;
}

@ Different conventions are followed by \TEX/ and \CEE/ to express octal
and hexadecimal numbers; it is reasonable to stick to each convention
within its realm.  Thus the \CEE/ part of a \.{CWEB} file has octals
introduced by \.0 and hexadecimals by \.{0x}, but \.{CWEAVE} will print
with \TEX/ macros that the user can redefine to fit the context.
In order to simplify such macros, we replace some of the characters.

On output, the \.{\ } that replaces \.{'} in \CPLUSPLUS/ literals will become
``\.{\\\ }''.

Notice that in this section and the next, |id_first| and |id_loc|
are pointers into the array |section_text|, not into |buffer|.

@d gather_digits_while(t) while ((t) || *loc=='\'')
  if (*loc=='\'') { /* \CPLUSPLUS/-style digit separator */
    *id_loc++=' '; loc++; /* insert a little bit of space */
  }@+else *id_loc++=*loc++

@<Get a constant@>= {
  id_first=id_loc=section_text+1;
  if (*(loc-1)=='.' && !xisdigit(*loc)) goto mistake; /* not a constant */
  if (*(loc-1)=='0') {
    if (*loc=='x' || *loc=='X') @<Get a hexadecimal constant@>@;
    else if (*loc=='b' || *loc=='B') @<Get a binary constant@>@;
    else if (xisdigit(*loc)) @<Get an octal constant@>@;
  }
  *id_loc++=*(loc-1); /* decimal constant */
  gather_digits_while(xisdigit(*loc) || *loc=='.');
get_exponent:
  if (*loc=='e' || *loc=='E')
    *id_loc++='_';
  else if (*loc=='p' || *loc=='P')
    *id_loc++='%';
  else
    goto digit_suffix;
  loc++;
  if (*loc=='+' || *loc=='-') *id_loc++=*loc++;
  gather_digits_while(xisdigit(*loc));
digit_suffix:
  while (*loc=='u' || *loc=='U' || *loc=='l' || *loc=='L'
         || *loc=='f' || *loc=='F') {
    *id_loc++='$'; *id_loc++=toupper((int)*loc); loc++;
  }
  return constant;
}

@ @<Get a hex...@>={
  *id_loc++='^'; loc++;
  gather_digits_while(xisxdigit(*loc) || *loc=='.');
  *id_loc++='/'; goto get_exponent;
}

@ @<Get a bin...@>={
  *id_loc++='\\'; loc++;
  gather_digits_while(*loc=='0' || *loc=='1');
  *id_loc++='/'; goto digit_suffix;
}

@ @<Get an oct...@>={
  *id_loc++='~'; gather_digits_while(xisdigit(*loc));
  *id_loc++='/'; goto digit_suffix;
}

@ \CEE/ strings and character constants, delimited by double and single
quotes, respectively, can contain newlines or instances of their own
delimiters if they are protected by a backslash.  We follow this
convention, but do not allow the string to be longer than |longest_name|.

@<Get a string@>= {@+
  char delim = c; /* what started the string */
  id_first = section_text+1;
  id_loc = section_text;
  if (delim=='\'' && *(loc-2)=='@@') {*++id_loc='@@'; *++id_loc='@@';}
  *++id_loc=delim;
  if (delim=='L' || delim=='u' || delim=='U')
    @<Get a wide character constant@>@;
  if (delim=='<') delim='>'; /* for file names in \#\&{include} lines */
  while (true) {
    if (loc>=limit) {
      if(*(limit-1)!='\\') {
        err_print("! String didn't end"); loc=limit; break;
@.String didn't end@>
      }
      if(get_line()==false) {
        err_print("! Input ended in middle of string"); loc=buffer; break;
@.Input ended in middle of string@>
      }
    }
    if ((c=*loc++)==delim) {
      if (++id_loc<=section_text_end) *id_loc=c;
      break;
    }
    if (c=='\\') {
      if (loc>=limit) continue;
      else {
        if (++id_loc<=section_text_end) {
          *id_loc = '\\'; c=*loc++;
        }
      }
    }
    if (++id_loc<=section_text_end) *id_loc=c;
  }
  if (id_loc>=section_text_end) {
    fputs("\n! String too long: ",stdout);
@.String too long@>
    term_write(section_text+1,25);
    printf("..."); mark_error;
  }
  id_loc++;
  return string;
}

@ @<Get a wide...@>={
  if (delim=='u' && *loc=='8') *++id_loc=*loc++;
  delim=*loc++; *++id_loc=delim;
}

@ After an \.{@@} sign has been scanned, the next character tells us
whether there is more work to do.

@<Get control code and possible section name@>=
switch(ccode[c=*loc++]) {
  case translit_code: err_print("! Use @@l in limbo only"); continue;
@.Use @@l in limbo...@>
  case underline: xref_switch=def_flag; continue;
  case trace: tracing=c-'0'; continue;
  case section_name:
    @<Scan the section name and make |cur_section| point to it@>@;
  case verbatim: @<Scan a verbatim string@>@;
  case ord: @<Get a string@>@;
  case xref_roman: case xref_wildcard: case xref_typewriter: case noop:
  case TeX_string: skip_restricted(); /* fall through */
  default: return ccode[c];
}

@ The occurrence of a section name sets |xref_switch| to zero,
because the section name might (for example) follow \&{int}.

@<Scan the section name...@>= {
  char *k=section_text; /* pointer into |section_text| */
  cur_section_char=*(loc-1);
  @<Put section name into |section_text|@>@;
  if (k-section_text>3 && strncmp(k-2,"...",3)==0)
        cur_section=section_lookup(section_text+1,k-3,true);
          /* |true| indicates a prefix */
  else cur_section=section_lookup(section_text+1,k,false);
  xref_switch=0; return section_name;
}

@ Section names are placed into the |section_text| array with consecutive spaces,
tabs, and carriage-returns replaced by single spaces. There will be no
spaces at the beginning or the end. (We set |section_text[0]=' '| to facilitate
this, since the |section_lookup| routine uses |section_text[1]| as the first
character of the name.)

@<Set init...@>=section_text[0]=' ';

@ @<Put section name...@>=
while (true) {
  if (loc>limit && get_line()==false) {
    err_print("! Input ended in section name");
@.Input ended in section name@>
    loc=buffer+1; break;
  }
  c=*loc;
  @<If end of name or erroneous control code, |break|@>@;
  loc++; if (k<section_text_end) k++;
  if (xisspace(c)) {
    c=' '; if (*(k-1)==' ') k--;
  }
*k=c;
}
if (k>=section_text_end) {
  fputs("\n! Section name too long: ",stdout);
@.Section name too long@>
  term_write(section_text+1,25);
  printf("..."); mark_harmless;
}
if (*k==' ' && k>section_text) k--;

@ @<If end of name...@>=
if (c=='@@') {
  c=*(loc+1);
  if (c=='>') {
    loc+=2; break;
  }
  if (ccode[c]==new_section) {
    err_print("! Section name didn't end"); break;
@.Section name didn't end@>
  }
  if (c!='@@') {
    err_print("! Control codes are forbidden in section name"); break;
@.Control codes are forbidden...@>
  }
  *(++k)='@@'; loc++; /* now |c==*loc| again */
}

@ This function skips over a restricted context at relatively high speed.

@c
static void
skip_restricted(void)
{
  id_first=loc; *(limit+1)='@@';
false_alarm:
  while (*loc!='@@') loc++;
  id_loc=loc;
  if (loc++>limit) {
    err_print("! Control text didn't end"); loc=limit;
@.Control text didn't end@>
  } else {
    if (*loc=='@@'&&loc<=limit) {loc++; goto false_alarm;}
    if (*loc++!='>')
      err_print("! Control codes are forbidden in control text");
@.Control codes are forbidden...@>
  }
}

@ @<Predecl...@>=@+static void skip_restricted(void);

@ At the present point in the program we
have |*(loc-1)==verbatim|; we set |id_first| to the beginning
of the string itself, and |id_loc| to its ending-plus-one location in the
buffer.  We also set |loc| to the position just after the ending delimiter.

@<Scan a verbatim string@>=
id_first=loc++; *(limit+1)='@@'; *(limit+2)='>';
while (*loc!='@@' || *(loc+1)!='>') loc++;
if (loc>=limit) err_print("! Verbatim string didn't end");
@.Verbatim string didn't end@>
id_loc=loc; loc+=2;
return verbatim;

@** Phase one processing.
We now have accumulated enough subroutines to make it possible to carry out
\.{CWEAVE}'s first pass over the source file. If everything works right,
both phase one and phase two of \.{CWEAVE} will assign the same numbers to
sections, and these numbers will agree with what \.{CTANGLE} does.

The global variable |next_control| often contains the most recent output of
|get_next|; in interesting cases, this will be the control code that
ended a section or part of a section.

@<Private...@>=
static eight_bits next_control; /* control code waiting to be acting upon */

@ The overall processing strategy in phase one has the following
straightforward outline.

@c
static void
phase_one(void) {
  phase=1; reset_input(); section_count=0;
  skip_limbo(); change_exists=false;
  while (!input_has_ended)
    @<Store cross-reference data for the current section@>@;
  changed_section[section_count]=change_exists;
    /* the index changes if anything does */
  @<Print error messages about unused or undefined section names@>@;
}

@ @<Predecl...@>=@+static void phase_one(void);

@ @<Store cross-reference data...@>=
{
  if (++section_count==max_sections) overflow("section number");
  changed_section[section_count]=changing;
     /* it will become |true| if any line changes */
  if (*(loc-1)=='*' && show_progress) {
    printf("*%d",(int)section_count);
    update_terminal; /* print a progress report */
  }
  @<Store cross-references in the \TEX/ part of a section@>@;
  @<Store cross-references in the definition part of a section@>@;
  @<Store cross-references in the \CEE/ part of a section@>@;
  if (changed_section[section_count]) change_exists=true;
}

@ The |C_xref| subroutine stores references to identifiers in
\CEE/ text material beginning with the current value of |next_control|
and continuing until |next_control| is `\.\{' or `\.{\v}', or until the next
``milestone'' is passed (i.e., |next_control>=format_code|). If
|next_control>=format_code| when |C_xref| is called, nothing will happen;
but if |next_control=='|'| upon entry, the procedure assumes that this is
the `\.{\v}' preceding \CEE/ text that is to be processed.

The parameter |spec_ctrl| is used to change this behavior. In most cases
|C_xref| is called with |spec_ctrl==ignore|, which triggers the default
processing described above. If |spec_ctrl==section_name|, section names will
be gobbled. This is used when \CEE/ text in the \TEX/ part or inside comments
is parsed: It allows for section names to appear in \pb, but these
strings will not be entered into the cross reference lists since they are not
definitions of section names.

The program uses the fact that our internal code numbers satisfy
the relations |xref_roman==identifier+roman| and |xref_wildcard==identifier
+wildcard| and |xref_typewriter==identifier+typewriter|,
as well as |normal==0|.

@<Predecl...@>=
static void C_xref(eight_bits);@/
static void outer_xref(void);

@ @c
static void
C_xref( /* makes cross-references for \CEE/ identifiers */
  eight_bits spec_ctrl)
{
  while (next_control<format_code || next_control==spec_ctrl) {
    if (next_control>=identifier && next_control<=xref_typewriter) {
      if (next_control>identifier) @<Replace `\.{@@@@}' by `\.{@@}'@>@;
      new_xref(id_lookup(id_first,id_loc,next_control-identifier));
    }
    if (next_control==section_name) {
      section_xref_switch=cite_flag;
      new_section_xref(cur_section);
    }
    next_control=get_next();
    if (next_control=='|' || next_control==begin_comment ||
        next_control==begin_short_comment) return;
  }
}

@ The |outer_xref| subroutine is like |C_xref| except that it begins
with |next_control!='|'| and ends with |next_control>=format_code|. Thus, it
handles \CEE/ text with embedded comments.

@c
static void
outer_xref(void) /* extension of |C_xref| */
{
  int bal; /* brace level in comment */
  while (next_control<format_code)
    if (next_control!=begin_comment && next_control!=begin_short_comment)
      C_xref(ignore);
    else {
      boolean is_long_comment=(next_control==begin_comment);
      bal=copy_comment(is_long_comment,1); next_control='|';
      while (bal>0) {
        C_xref(section_name); /* do not reference section names in comments */
        if (next_control=='|') bal=copy_comment(is_long_comment,bal);
        else bal=0; /* an error message will occur in phase two */
      }
    }
}

@ In the \TEX/ part of a section, cross-reference entries are made only for
the identifiers in \CEE/ texts enclosed in \pb, or for control texts
enclosed in \.{@@\^}$\,\ldots\,$\.{@@>} or \.{@@.}$\,\ldots\,$\.{@@>}
or \.{@@:}$\,\ldots\,$\.{@@>}.

@<Store cross-references in the \T...@>=
while (true) {
  switch (next_control=skip_TeX()) {
    case translit_code: err_print("! Use @@l in limbo only"); continue;
@.Use @@l in limbo...@>
    case underline: xref_switch=def_flag; continue;
    case trace: tracing=*(loc-1)-'0'; continue;
    case '|': C_xref(section_name); break;
    case xref_roman: case xref_wildcard: case xref_typewriter:
    case noop: case section_name:
      loc-=2; next_control=get_next(); /* scan to \.{@@>} */
      if (next_control>=xref_roman && next_control<=xref_typewriter) {
        @<Replace `\.{@@@@}' by `\.{@@}'@>@;
        new_xref(id_lookup(id_first,id_loc,next_control-identifier));
      }
      break;
  }
  if (next_control>=format_code) break;
}

@ @<Replace `\.{@@@@}' by `\.{@@}'@>=
{
  char *src=id_first,*dst=id_first;
  while(src<id_loc){
    if(*src=='@@') src++;
    *dst++=*src++;
  }
  id_loc=dst;
  while (dst<src) *dst++=' '; /* clean up in case of error message display */
}

@ During the definition and \CEE/ parts of a section, cross-references
are made for all identifiers except reserved words. However, the right
identifier in a format definition is not referenced, and the left
identifier is referenced only if it has been explicitly
underlined (preceded by \.{@@!}).
The \TEX/ code in comments is, of course, ignored, except for
\CEE/ portions enclosed in \pb; the text of a section name is skipped
entirely, even if it contains \pb\ constructions.

The variables |lhs| and |rhs| point to the respective identifiers involved
in a format definition.

@<Private...@>=
static name_pointer lhs, rhs; /* pointers to |byte_start| for format identifiers */
static name_pointer res_wd_end; /* pointer to the first nonreserved identifier */

@ When we get to the following code we have |next_control>=format_code|.

@<Store cross-references in the d...@>=
while (next_control<=definition) { /* |format_code| or |definition| */
  if (next_control==definition) {
    xref_switch=def_flag; /* implied \.{@@!} */
    next_control=get_next();
  } else @<Process a format definition@>@;
  outer_xref();
}

@ Error messages for improper format definitions will be issued in phase
two. Our job in phase one is to define the |ilk| of a properly formatted
identifier, and to remove cross-references to identifiers that we now
discover should be unindexed.

@<Process a form...@>= {
  next_control=get_next();
  if (next_control==identifier) {
    lhs=id_lookup(id_first, id_loc,normal); lhs->ilk=normal;
    if (xref_switch) new_xref(lhs);
    next_control=get_next();
    if (next_control==identifier) {
      rhs=id_lookup(id_first, id_loc,normal);
      lhs->ilk=rhs->ilk;
      if (unindexed(lhs)) { /* retain only underlined entries */
        xref_pointer q,r=NULL;
        for (q=(xref_pointer)lhs->xref;q>xmem;q=q->xlink)
          if (q->num<def_flag)
            if (r) r->xlink=q->xlink;
            else lhs->xref=(void *)q->xlink;
          else r=q;
      }
      next_control=get_next();
    }
  }
}

@ A much simpler processing of format definitions occurs when the
definition is found in limbo.

@<Process simple format in limbo@>=
if (get_next()!=identifier)
  err_print("! Missing left identifier of @@s");
@.Missing left identifier...@>
else {
  lhs=id_lookup(id_first,id_loc,normal);
  if (get_next()!=identifier)
    err_print("! Missing right identifier of @@s");
@.Missing right identifier...@>
  else {
    rhs=id_lookup(id_first,id_loc,normal);
    lhs->ilk=rhs->ilk;
  }
}

@ Finally, when the \TEX/ and definition parts have been treated, we have
|next_control>=begin_C|.

@<Store cross-references in the \CEE/...@>=
if (next_control<=section_name) { /* |begin_C| or |section_name| */
  if (next_control==begin_C) section_xref_switch=0;
  else {
    section_xref_switch=def_flag;
    if(cur_section_char=='(' && cur_section!=name_dir)
      set_file_flag(cur_section);
  }
  do {
    if (next_control==section_name && cur_section!=name_dir)
      new_section_xref(cur_section);
    next_control=get_next(); outer_xref();
  } while ( next_control<=section_name);
}

@ After phase one has looked at everything, we want to check that each
section name was both defined and used.  The variable |cur_xref| will point
to cross-references for the current section name of interest.

@<Private...@>=
static xref_pointer cur_xref; /* temporary cross-reference pointer */
static boolean an_output; /* did |file_flag| precede |cur_xref|? */

@ The following recursive procedure
walks through the tree of section names and prints out anomalies.
@^recursion@>

@c
static void
section_check(
name_pointer p) /* print anomalies in subtree |p| */
{
  if (p) {
    section_check(p->llink);
    cur_xref=(xref_pointer)p->xref;
    if ((an_output=(cur_xref->num==file_flag))==true) cur_xref=cur_xref->xlink;
    if (cur_xref->num <def_flag) {
      fputs("\n! Never defined: <",stdout);
      print_section_name(p); putchar('>'); mark_harmless;
@.Never defined: <section name>@>
    }
    while (cur_xref->num >=cite_flag) cur_xref=cur_xref->xlink;
    if (cur_xref==xmem && !an_output) {
      fputs("\n! Never used: <",stdout);
      print_section_name(p); putchar('>'); mark_harmless;
@.Never used: <section name>@>
    }
    section_check(p->rlink);
  }
}

@ @<Predecl...@>=@+static void section_check(name_pointer);

@ @<Print error messages about un...@>=section_check(root);

@* Low-level output routines.
The \TEX/ output is supposed to appear in lines at most |line_length|
characters long, so we place it into an output buffer. During the output
process, |out_line| will hold the current line number of the line about to
be output.

@<Private...@>=
static char out_buf[line_length+1]; /* assembled characters */
static char *out_buf_end = out_buf+line_length; /* end of |out_buf| */
static char *out_ptr; /* last character in |out_buf| */
static int out_line; /* number of next line to be output */

@ The |flush_buffer| routine empties the buffer up to a given breakpoint,
and moves any remaining characters to the beginning of the next line.
If the |per_cent| parameter is |true|, a |'%'| is appended to the line
that is being output; in this case the breakpoint |b| should be strictly
less than |out_buf_end|. If the |per_cent| parameter is |false|,
trailing blanks are suppressed.
The characters emptied from the buffer form a new line of output;
if the |carryover| parameter is |true|, a |"%"| in that line will be
carried over to the next line (so that \TEX/ will ignore the completion
of commented-out text).

@d c_line_write(c) fflush(active_file),fwrite(out_buf+1,sizeof(char),c,active_file)
@d tex_putc(c) putc(c,active_file)
@d tex_new_line putc('\n',active_file)
@d tex_printf(c) fprintf(active_file,"%s",c)
@d tex_puts(c) fputs(c,active_file)

@<Predecl...@>=
static void flush_buffer(char *,boolean,boolean);@/
static void finish_line(void);

@ @c
static void
flush_buffer(
char *b, /* outputs from |out_buf+1| to |b|, where |b<=out_ptr| */
boolean per_cent,boolean carryover)
{
  char *j=b; /* pointer into |out_buf| */
  if (! per_cent) /* remove trailing blanks */
    while (j>out_buf && *j==' ') j--;
  c_line_write(j-out_buf);
  if (per_cent) tex_putc('%');
  tex_new_line; out_line++;
  if (carryover)
    while (j>out_buf)
      if (*j--=='%' && (j==out_buf || *j!='\\')) {
        *b--='%'; break;
      }
  if (b<out_ptr) memcpy(out_buf+1,b+1,(size_t)(out_ptr-b));
  out_ptr-=b-out_buf;
}

@ When we are copying \TEX/ source material, we retain line breaks
that occur in the input, except that an empty line is not
output when the \TEX/ source line was nonempty. For example, a line
of the \TEX/ file that contains only an index cross-reference entry
will not be copied. The |finish_line| routine is called just before
|get_line| inputs a new line, and just after a line break token has
been emitted during the output of translated \CEE/ text.

@c
static void
finish_line(void) /* do this at the end of a line */
{
  char *k; /* pointer into |buffer| */
  if (out_ptr>out_buf) flush_buffer(out_ptr,false,false);
  else {
    for (k=buffer; k<=limit; k++)
      if (!(xisspace(*k))) return;
    flush_buffer(out_buf,false,false);
  }
}

@ In particular, the |finish_line| procedure is called near the very
beginning of phase two. We initialize the output variables in a slightly
tricky way so that the first line of the output file will be
`\.{\\input cwebmac}'.

@<Start \TEX/...@>=
out_ptr=out_buf+1; out_line=1; active_file=tex_file;
tex_printf("\\input cwebma"); *out_ptr='c';

@ When we wish to append one character |c| to the output buffer, we write
`|out(c)|'; this will cause the buffer to be emptied if it was already
full.  If we want to append more than one character at once, we say
|out_str(s)|, where |s| is a string containing the characters.

A line break will occur at a space or after a single-nonletter
\TEX/ control sequence.

@d out(c) {if (out_ptr>=out_buf_end) break_out(); *(++out_ptr)=c;}

@<Predecl...@>=
static void out_str(const char *);@/
static void break_out(void);

@ @c
static void
out_str( /* output characters from |s| to end of string */
const char*s)
{
  while (*s) out(*s++);
}

@ The |break_out| routine is called just before the output buffer is about
to overflow. To make this routine a little faster, we initialize position
0 of the output buffer to `\.\\'; this character isn't really output.

@<Set init...@>=
out_buf[0]='\\';

@ A long line is broken at a blank space or just before a backslash that isn't
preceded by another backslash. In the latter case, a |'%'| is output at
the break.

@c
static void
break_out(void) /* finds a way to break the output line */
{
  char *k=out_ptr; /* pointer into |out_buf| */
  while (true) {
    if (k==out_buf) @<Print warning message, break the line, |return|@>@;
    if (*k==' ') {
      flush_buffer(k,false,true); return;
    }
    if (*(k--)=='\\' && *k!='\\') { /* we've decreased |k| */
      flush_buffer(k,true,true); return;
    }
  }
}

@ We get to this section only in the unusual case that the entire output line
consists of a string of backslashes followed by a string of nonblank
non-backslashes. In such cases it is almost always safe to break the
line by putting a |'%'| just before the last character.

@<Print warning message...@>=
{
  printf("\n! Line had to be broken (output l. %d):\n",out_line);
@.Line had to be broken@>
  term_write(out_buf+1, out_ptr-out_buf-1);
  new_line; mark_harmless;
  flush_buffer(out_ptr-1,true,true); return;
}

@ Here is a macro that outputs a section number in decimal notation.
The number to be converted by |out_section| is known to be less than
|def_flag|, so it cannot have more than five decimal digits.  If
the section is changed, we output `\.{\\*}' just after the number.

@<Predecl...@>=
static void out_section(sixteen_bits);@/
static void out_name(name_pointer,boolean);

@ @c
static void
out_section(
sixteen_bits n)
{
  char s[6];
  sprintf(s,"%d",(int)n); out_str(s);
  if (changed_section[n]) out_str("\\*");
@.\\*@>
}

@ The |out_name| procedure is used to output an identifier or index
entry, enclosing it in braces.

@c
static void
out_name(
name_pointer p,
boolean quote_xalpha)
{
  char *k, *k_end=(p+1)->byte_start; /* pointers into |byte_mem| */
  out('{');
  for (k=p->byte_start; k<k_end; k++) {
    if (isxalpha(*k) && quote_xalpha) out('\\');
@.\\\$@>
@.\\\_@>
    out(*k);
  }
  out('}');
}

@* Routines that copy \TEX/ material.
During phase two, we use the subroutines |copy_limbo| and |copy_TeX| (and
|copy_comment|) in place of the analogous |skip_limbo| and |skip_TeX|
that were used in phase one.

The |copy_limbo| routine, for example, takes \TEX/ material that is not
part of any section and transcribes it almost verbatim to the output file.
The use of `\.{@@}' signs is severely restricted in such material:
`\.{@@@@}' pairs are replaced by singletons; `\.{@@l}' and `\.{@@q}' and
`\.{@@s}' are interpreted.

@<Predecl...@>=
static void copy_limbo(void);@/
static eight_bits copy_TeX(void);@/
static int copy_comment(boolean,int);

@ @c
static void
copy_limbo(void)
{
  while (true) {
    if (loc>limit && (finish_line(), get_line()==false)) return;
    *(limit+1)='@@';
    while (*loc!='@@') out(*(loc++));
    if (loc++<=limit) {
      switch (ccode[(eight_bits)*loc++]) {
        case new_section: return;
        case translit_code: out_str("\\ATL"); break;
@.\\ATL@>
        case '@@': out('@@'); break;
        case noop: skip_restricted(); break;
        case format_code: if (get_next()==identifier) get_next();
          if (loc>=limit) get_line(); /* avoid blank lines in output */
          break; /* the operands of \.{@@s} are ignored on this pass */
        default: err_print("! Double @@ should be used in limbo");
@.Double @@ should be used...@>
        out('@@');
      }
    }
  }
}

@ The |copy_TeX| routine processes the \TEX/ code at the beginning of a
section; for example, the words you are now reading were copied in this
way. It returns the next control code or `\.{\v}' found in the input.
We don't copy spaces or tab marks into the beginning of a line. This
makes the test for empty lines in |finish_line| work.

@f copy_TeX TeX
@c
static eight_bits
copy_TeX(void)
{
  char c; /* current character being copied */
  while (true) {
    if (loc>limit && (finish_line(), get_line()==false)) return new_section;
    *(limit+1)='@@';
    while ((c=*(loc++))!='|' && c!='@@') {
      out(c);
      if (out_ptr==out_buf+1 && (xisspace(c))) out_ptr--;
    }
    if (c=='|') return '|';
    if (loc<=limit) return ccode[(eight_bits)*(loc++)];
  }
}

@ The |copy_comment| function issues a warning if more braces are opened than
closed, and in the case of a more serious error it supplies enough
braces to keep \TEX/ from complaining about unbalanced braces.
Instead of copying the \TEX/ material
into the output buffer, this function copies it into the token memory
(in phase two only).
The abbreviation |app_tok(t)| is used to append token |t| to the current
token list, and it also makes sure that it is possible to append at least
one further token without overflow.

@d app_tok(c) {if (tok_ptr+2>tok_mem_end) overflow("token"); *(tok_ptr++)=c;}

@c
static int copy_comment( /* copies \TeX\ code in comments */
boolean is_long_comment, /* is this a traditional \CEE/ comment? */
int bal) /* brace balance */
{
  char c; /* current character being copied */
  while (true) {
    if (loc>limit) {
      if (is_long_comment) {
        if (get_line()==false) {
          err_print("! Input ended in mid-comment");
@.Input ended in mid-comment@>
          loc=buffer+1; goto done;
        }
      } else {
        if (bal>1) err_print("! Missing } in comment");
@.Missing \} in comment@>
        goto done;
      }
    }
    c=*(loc++);
    if (c=='|') return bal;
    if (is_long_comment) @<Check for end of comment@>@;
    if (phase==2) {
      if (ishigh(c)) app_tok(quoted_char);
      app_tok(c);
    }
    @<Copy special things when |c=='@@', '\\'|@>@;
    if (c=='{') bal++;
    else if (c=='}') {
      if(bal>1) bal--;
      else {err_print("! Extra } in comment");
@.Extra \} in comment@>
        if (phase==2) tok_ptr--;
      }
    }
  }
done: @<Clear |bal| and |return|@>@;
}

@ @<Check for end of comment@>=
if (c=='*' && *loc=='/') {
  loc++;
  if (bal>1) err_print("! Missing } in comment");
@.Missing \} in comment@>
  goto done;
}

@ @<Copy special things when |c=='@@'...@>=
if (c=='@@') {
  if (*(loc++)!='@@') {
    err_print("! Illegal use of @@ in comment");
@.Illegal use of @@...@>
    loc-=2; if (phase==2) *(tok_ptr-1)=' '; goto done;
  }
} else {
  if (c=='\\' && *loc!='@@') {
    if (phase==2) app_tok(*(loc++))@t;@>@; else loc++;
  }
}

@ We output
enough right braces to keep \TEX/ happy.

@<Clear |bal|...@>=
if (phase==2) while (bal-- >0) app_tok('}');
return 0;

@** Parsing.
The most intricate part of \.{CWEAVE} is its mechanism for converting
\CEE/-like code into \TEX/ code, and we might as well plunge into this
aspect of the program now. A ``bottom up'' approach is used to parse the
\CEE/-like material, since \.{CWEAVE} must deal with fragmentary
constructions whose overall ``part of speech'' is not known.

At the lowest level, the input is represented as a sequence of entities
that we shall call {\it scraps}, where each scrap of information consists
of two parts, its {\it category} and its {\it translation}. The category
is essentially a syntactic class, and the translation is a token list that
represents \TEX/ code. Rules of syntax and semantics tell us how to
combine adjacent scraps into larger ones, and if we are lucky an entire
\CEE/ text that starts out as hundreds of small scraps will join
together into one gigantic scrap whose translation is the desired \TEX/
code. If we are unlucky, we will be left with several scraps that don't
combine; their translations will simply be output, one by one.

The combination rules are given as context-sensitive productions that are
applied from left to right. Suppose that we are currently working on the
sequence of scraps $s_1\,s_2\ldots s_n$. We try first to find the longest
production that applies to an initial substring $s_1\,s_2\ldots\,$; but if
no such productions exist, we try to find the longest production
applicable to the next substring $s_2\,s_3\ldots\,$; and if that fails, we
try to match $s_3\,s_4\ldots\,$, etc.

A production applies if the category codes have a given pattern. For
example, one of the productions (see rule~3) is
$$\hbox{|exp| }\left\{\matrix{\hbox{|binop|}\cr\hbox{|ubinop|}}\right\}
\hbox{ |exp| }\RA\hbox{ |exp|}$$
and it means that three consecutive scraps whose respective categories are
|exp|, |binop| (or |ubinop|),
and |exp| are converted to one scrap whose category
is |exp|.  The translations of the original
scraps are simply concatenated.  The case of
$$\hbox{|exp| |comma| |exp| $\RA$ |exp|} \hskip4emE_1C\,\\{opt}9\,E_2$$
(rule 4) is only slightly more complicated:
Here the resulting |exp| translation
consists not only of the three original translations, but also of the
tokens |opt| and 9 between the translations of the
|comma| and the following |exp|.
In the \TEX/ file, this will specify an optional line break after the
comma, with penalty 90.

At each opportunity the longest possible production is applied.  For
example, if the current sequence of scraps is |if_clause| |stmt|
|else_like| |if_like|, rule 63 is applied; but if the sequence is
|if_clause| |stmt| |else_like| followed by anything other than
|if_like|, rule 64 takes effect; and if the sequence is |if_clause|
|stmt| followed by anything other than |else_like|, rule 65 takes
effect.

Translation rules such as `$E_1C\,\\{opt}9\,E_2$' above use subscripts
to distinguish between translations of scraps whose categories have the
same initial letter; these subscripts are assigned from left to right.

@ Here is a list of the category codes that scraps can have.
(A few others, like |int_like|, have already been defined; the
|cat_name| array contains a complete list.)

@d exp 1 /* denotes an expression, including perhaps a single identifier */
@d unop 2 /* denotes a unary operator */
@d binop 3 /* denotes a binary operator */
@d ubinop 4
  /* denotes an operator that can be unary or binary, depending on context */
@d cast 5 /* denotes a cast */
@d question 6 /* denotes a question mark and possibly the expressions flanking it */
@d lbrace 7 /* denotes a left brace */
@d rbrace 8 /* denotes a right brace */
@d decl_head 9 /* denotes an incomplete declaration */
@d comma 10 /* denotes a comma */
@d lpar 11 /* denotes a left parenthesis */
@d rpar 12 /* denotes a right parenthesis */
@d prelangle 13 /* denotes `$<$' before we know what it is */
@d prerangle 14 /* denotes `$>$' before we know what it is */
@d langle 15 /* denotes `$<$' when it's used as angle bracket in a template */
@d colcol 18 /* denotes `::' */
@d base 19 /* denotes a colon that introduces a base specifier */
@d decl 20 /* denotes a complete declaration */
@d struct_head 21 /* denotes the beginning of a structure specifier */
@d stmt 23 /* denotes a complete statement */
@d function 24 /* denotes a complete function */
@d fn_decl 25 /* denotes a function declarator */
@d semi 27 /* denotes a semicolon */
@d colon 28 /* denotes a colon */
@d tag 29 /* denotes a statement label */
@d if_head 30 /* denotes the beginning of a compound conditional */
@d else_head 31 /* denotes a prefix for a compound statement */
@d if_clause 32 /* pending \.{if} together with a condition */
@d lproc 35 /* begins a preprocessor command */
@d rproc 36 /* ends a preprocessor command */
@d insert 37 /* a scrap that gets combined with its neighbor */
@d section_scrap 38 /* section name */
@d dead 39 /* scrap that won't combine */
@d ftemplate 63 /* \\{make\_pair} */
@d new_exp 64 /* \&{new} and a following type identifier */
@d begin_arg 65 /* \.{@@[} */
@d end_arg 66 /* \.{@@]} */
@d lbrack 67 /* denotes a left bracket */
@d rbrack 68 /* denotes a right bracket */
@d attr_head 69 /* denotes beginning of attribute */

@<Private...@>=
static char cat_name[256][12]; /* |12==strlen("struct_head")+1| */

@ @<Set in...@>=
{int c; for (c=0;c<256;c++) strcpy(cat_name[c],"UNKNOWN");}
@.UNKNOWN@>
    strcpy(cat_name[exp],"exp");
    strcpy(cat_name[unop],"unop");
    strcpy(cat_name[binop],"binop");
    strcpy(cat_name[ubinop],"ubinop");
    strcpy(cat_name[cast],"cast");
    strcpy(cat_name[question],"?");
    strcpy(cat_name[lbrace],"{"@q}@>);
    strcpy(cat_name[rbrace],@q{@>"}");
    strcpy(cat_name[decl_head],"decl_head");
    strcpy(cat_name[comma],",");
    strcpy(cat_name[lpar],"(");
    strcpy(cat_name[rpar],")");
    strcpy(cat_name[prelangle],"<");
    strcpy(cat_name[prerangle],">");
    strcpy(cat_name[langle],"\\<");
    strcpy(cat_name[colcol],"::");
    strcpy(cat_name[base],"\\:");
    strcpy(cat_name[decl],"decl");
    strcpy(cat_name[struct_head],"struct_head");
    strcpy(cat_name[alfop],"alfop");
    strcpy(cat_name[stmt],"stmt");
    strcpy(cat_name[function],"function");
    strcpy(cat_name[fn_decl],"fn_decl");
    strcpy(cat_name[else_like],"else_like");
    strcpy(cat_name[semi],";");
    strcpy(cat_name[colon],":");
    strcpy(cat_name[tag],"tag");
    strcpy(cat_name[if_head],"if_head");
    strcpy(cat_name[else_head],"else_head");
    strcpy(cat_name[if_clause],"if()");
    strcpy(cat_name[lproc],"#{"@q}@>);
    strcpy(cat_name[rproc],@q{@>"#}");
    strcpy(cat_name[insert],"insert");
    strcpy(cat_name[section_scrap],"section");
    strcpy(cat_name[dead],"@@d");
    strcpy(cat_name[public_like],"public");
    strcpy(cat_name[operator_like],"operator");
    strcpy(cat_name[new_like],"new");
    strcpy(cat_name[catch_like],"catch");
    strcpy(cat_name[for_like],"for");
    strcpy(cat_name[do_like],"do");
    strcpy(cat_name[if_like],"if");
    strcpy(cat_name[delete_like],"delete");
    strcpy(cat_name[raw_ubin],"ubinop?");
    strcpy(cat_name[const_like],"const");
    strcpy(cat_name[raw_int],"raw");
    strcpy(cat_name[int_like],"int");
    strcpy(cat_name[case_like],"case");
    strcpy(cat_name[sizeof_like],"sizeof");
    strcpy(cat_name[struct_like],"struct");
    strcpy(cat_name[typedef_like],"typedef");
    strcpy(cat_name[define_like],"define");
    strcpy(cat_name[template_like],"template");
    strcpy(cat_name[ftemplate],"ftemplate");
    strcpy(cat_name[new_exp],"new_exp");
    strcpy(cat_name[begin_arg],"@@["@q]@>);
    strcpy(cat_name[end_arg],@q[@>"@@]");
    strcpy(cat_name[lbrack],"[");
    strcpy(cat_name[rbrack],"]");
    strcpy(cat_name[attr_head],"attr_head");
    strcpy(cat_name[attr],"attr");
    strcpy(cat_name[alignas_like],"alignas");
    strcpy(cat_name[using_like],"using");
    strcpy(cat_name[default_like],"default");
    strcpy(cat_name[0],"zero");

@ This code allows \.{CWEAVE} to display its parsing steps.

@d print_cat(c) fputs(cat_name[c],stdout)

@ The token lists for translated \TEX/ output contain some special control
symbols as well as ordinary characters. These control symbols are
interpreted by \.{CWEAVE} before they are written to the output file.

\yskip\hang |break_space| denotes an optional line break or an en space;

\yskip\hang |force| denotes a line break;

\yskip\hang |big_force| denotes a line break with additional vertical space;

\yskip\hang |preproc_line| denotes that the line will be printed flush left;

\yskip\hang |opt| denotes an optional line break (with the continuation
line indented two ems with respect to the normal starting position)---this
code is followed by an integer |n|, and the break will occur with penalty
$10n$;

\yskip\hang |backup| denotes a backspace of one em;

\yskip\hang |cancel| obliterates any |break_space|, |opt|, |force|, or
|big_force| tokens that immediately precede or follow it and also cancels any
|backup| tokens that follow it;

\yskip\hang |indent| causes future lines to be indented one more em;

\yskip\hang |outdent| causes future lines to be indented one less em;

\yskip\hang |dindent| causes future lines to be indented two more ems.

\yskip\noindent All of these tokens are removed from the \TEX/ output that
comes from \CEE/ text between \pb\ signs; |break_space| and |force| and
|big_force| become single spaces in this mode. The translation of other
\CEE/ texts results in \TEX/ control sequences \.{\\1}, \.{\\2},
\.{\\3}, \.{\\4}, \.{\\5}, \.{\\6}, \.{\\7}, \.{\\8}
corresponding respectively to
|indent|, |outdent|, |opt|, |backup|, |break_space|, |force|,
|big_force| and |preproc_line|.
However, a sequence of consecutive `\.\ ', |break_space|,
|force|, and/or |big_force| tokens is first replaced by a single token
(the maximum of the given ones).

A |dindent| token becomes \.{\\1\\1}. It is equivalent to a pair of |indent|
tokens. However, if |dindent| immediately precedes |big_force|, the two tokens
are swapped, so that the indentation happens after the line break.

The token |math_rel| will be translated into
\.{\\MRL\{}, and it will get a matching \.\} later.
Other control sequences in the \TEX/ output will be
`\.{\\\\\{}$\,\ldots\,$\.\}'
surrounding identifiers, `\.{\\\&\{}$\,\ldots\,$\.\}' surrounding
reserved words, `\.{\\.\{}$\,\ldots\,$\.\}' surrounding strings,
`\.{\\C\{}$\,\ldots\,$\.\}$\,$|force|' surrounding comments, and
`\.{\\X$n$:}$\,\ldots\,$\.{\\X}' surrounding section names, where
|n| is the section number.

@d math_rel 0206
@d big_cancel 0210 /* like |cancel|, also overrides spaces */
@d cancel 0211 /* overrides |backup|, |break_space|, |force|, |big_force| */
@d indent 0212 /* one more tab (\.{\\1}) */
@d outdent 0213 /* one less tab (\.{\\2}) */
@d opt 0214 /* optional break in mid-statement (\.{\\3}) */
@d backup 0215 /* stick out one unit to the left (\.{\\4}) */
@d break_space 0216 /* optional break between statements (\.{\\5}) */
@d force 0217 /* forced break between statements (\.{\\6}) */
@d big_force 0220 /* forced break with additional space (\.{\\7}) */
@d preproc_line 0221 /* begin line without indentation (\.{\\8}) */
@^high-bit character handling@>
@d quoted_char 0222
        /* introduces a character token in the range |0200|--|0377| */
@d end_translation 0223 /* special sentinel token at end of list */
@d inserted 0224 /* sentinel to mark translations of inserts */
@d qualifier 0225 /* introduces an explicit namespace qualifier */
@d dindent 0226 /* two more tabs (\.{\\1\\1}) */

@ The raw input is converted into scraps according to the following table,
which gives category codes followed by the translations.
\def\stars {\.{**}}%
The symbol `\stars' stands for `\.{\\\&\{{\rm identifier}\}}',
i.e., the identifier itself treated as a reserved word.
The right-hand column is the so-called |mathness|, which is explained
further below.

An identifier |c| of length 1 is translated as \.{\\\v c} instead of
as \.{\\\\\{c\}}. An identifier \.{CAPS} in all caps is translated as
\.{\\.\{CAPS\}} instead of as \.{\\\\\{CAPS\}}. An identifier that has
become a reserved word via |typedef| is translated with \.{\\\&} replacing
\.{\\\\} and |raw_int| replacing |exp|.

A string of length greater than 20 is broken into pieces of size at most~20
with discretionary breaks in between.

\yskip\halign{\quad#\hfil&\quad#\hfil&\quad\hfil#\hfil\cr
\.{!=}&|binop|: \.{\\I}&yes\cr
\.{<=}&|binop|: \.{\\Z}&yes\cr
\.{>=}&|binop|: \.{\\G}&yes\cr
\.{==}&|binop|: \.{\\E}&yes\cr
\.{\&\&}&|binop|: \.{\\W}&yes\cr
\.{\v\v}&|binop|: \.{\\V}&yes\cr
\.{++}&|unop|: \.{\\PP}&yes\cr
\.{--}&|unop|: \.{\\MM}&yes\cr
\.{->}&|binop|: \.{\\MG}&yes\cr
\.{>>}&|binop|: \.{\\GG}&yes\cr
\.{<<}&|binop|: \.{\\LL}&yes\cr
\.{::}&|colcol|: \.{\\DC}&maybe\cr
\.{.*}&|binop|: \.{\\PA}&yes\cr
\.{->*}&|binop|: \.{\\MGA}&yes\cr
\.{...}&|raw_int|: \.{\\,\\ldots\\,}&yes\cr
\."string\."&|exp|: \.{\\.\{}string with special characters quoted\.\}&maybe\cr
\.{@@=}string\.{@@>}&|exp|: \.{\\vb\{}string with special characters
  quoted\.\}&maybe\cr
\.{@@'7'}&|exp|: \.{\\.\{@@'7'\}}&maybe\cr
\.{077} or \.{\\77}&|exp|: \.{\\T\{\\\~77/\}}&maybe\cr
\.{0x7f}&|exp|: \.{\\T\{\\\^7f/\}}&maybe\cr
\.{0b10111}&|exp|: \.{\\T\{\\\\10111/\}}&maybe\cr
\.{77}&|exp|: \.{\\T\{77\}}&maybe\cr
\.{77L}&|exp|: \.{\\T\{77\\\$L\}}&maybe\cr
\.{0.1E5}&|exp|: \.{\\T\{0.1\\\_5\}}&maybe\cr
\.{0x10p3}&|exp|: \.{\\T\{\\\^10/\\\%3\}}&maybe\cr
\.{1'000'000}&|exp|: \.{\\T\{1\\\ 000\\\ 000\}}&maybe\cr
\.+&|ubinop|: \.+&yes\cr
\.-&|ubinop|: \.-&yes\cr
\.*&|raw_ubin|: \.*&yes\cr
\./&|binop|: \./&yes\cr
\.<&|prelangle|: \.{\\langle}&yes\cr
\.=&|binop|: \.{\\K}&yes\cr
\.>&|prerangle|: \.{\\rangle}&yes\cr
\..&|binop|: \..&yes\cr
\.{\v}&|binop|: \.{\\OR}&yes\cr
\.\^&|binop|: \.{\\XOR}&yes\cr
\.\%&|binop|: \.{\\MOD}&yes\cr
\.?&|question|: \.{\\?}&yes\cr
\.!&|unop|: \.{\\R}&yes\cr
\.\~&|unop|: \.{\\CM}&yes\cr
\.\&&|raw_ubin|: \.{\\AND}&yes\cr
\.(&|lpar|: \.(&maybe\cr
\.)&|rpar|: \.)&maybe\cr
\.[&|lbrack|: \.[&maybe\cr
\.]&|rbrack|: \.]&maybe\cr
\.\{&|lbrace|: \.\{&yes\cr
\.\}&|lbrace|: \.\}&yes\cr
\.,&|comma|: \.,&yes\cr
\.;&|semi|: \.;&maybe\cr
\.:&|colon|: \.:&no\cr
\.\# (within line)&|ubinop|: \.{\\\#}&yes\cr
\.\# (at beginning)&|lproc|: |force| |preproc_line| \.{\\\#}&no\cr
end of \.\# line&|rproc|: |force|&no\cr
identifier&|exp|: \.{\\\\\{}identifier with underlines and
             dollar signs quoted\.\}&maybe\cr
\.{alignas}&|alignas_like|: \stars&maybe\cr
\.{alignof}&|sizeof_like|: \stars&maybe\cr
\.{and}&|alfop|: \stars&yes\cr
\.{and\_eq}&|alfop|: \stars&yes\cr
\.{asm}&|sizeof_like|: \stars&maybe\cr
\.{auto}&|int_like|: \stars&maybe\cr
\.{bitand}&|alfop|: \stars&yes\cr
\.{bitor}&|alfop|: \stars&yes\cr
\.{bool}&|raw_int|: \stars&maybe\cr
\.{break}&|case_like|: \stars&maybe\cr
\.{case}&|case_like|: \stars&maybe\cr
\.{catch}&|catch_like|: \stars&maybe\cr
\.{char}&|raw_int|: \stars&maybe\cr
\.{char8\_t}&|raw_int|: \stars&maybe\cr
\.{char16\_t}&|raw_int|: \stars&maybe\cr
\.{char32\_t}&|raw_int|: \stars&maybe\cr
\.{class}&|struct_like|: \stars&maybe\cr
\.{clock\_t}&|raw_int|: \stars&maybe\cr
\.{compl}&|alfop|: \stars&yes\cr
\.{complex}&|int_like|: \stars&yes\cr
\.{concept}&|int_like|: \stars&maybe\cr
\.{const}&|const_like|: \stars&maybe\cr
\.{consteval}&|const_like|: \stars&maybe\cr
\.{constexpr}&|const_like|: \stars&maybe\cr
\.{constinit}&|const_like|: \stars&maybe\cr
\.{const\_cast}&|raw_int|: \stars&maybe\cr
\.{continue}&|case_like|: \stars&maybe\cr
\.{co\_await}&|case_like|: \stars&maybe\cr
\.{co\_return}&|case_like|: \stars&maybe\cr
\.{co\_yield}&|case_like|: \stars&maybe\cr
\.{decltype}&|sizeof_like|: \stars&maybe\cr
\.{default}&|default_like|: \stars&maybe\cr
\.{define}&|define_like|: \stars&maybe\cr
\.{defined}&|sizeof_like|: \stars&maybe\cr
\.{delete}&|delete_like|: \stars&maybe\cr
\.{div\_t}&|raw_int|: \stars&maybe\cr
\.{do}&|do_like|: \stars&maybe\cr
\.{double}&|raw_int|: \stars&maybe\cr
\.{dynamic\_cast}&|raw_int|: \stars&maybe\cr
\.{elif}&|if_like|: \stars&maybe\cr
\.{else}&|else_like|: \stars&maybe\cr
\.{endif}&|if_like|: \stars&maybe\cr
\.{enum}&|struct_like|: \stars&maybe\cr
\.{error}&|if_like|: \stars&maybe\cr
\.{explicit}&|int_like|: \stars&maybe\cr
\.{export}&|int_like|: \stars&maybe\cr
\.{extern}&|int_like|: \stars&maybe\cr
\.{FILE}&|raw_int|: \stars&maybe\cr
\.{false}&|normal|: \stars&maybe\cr
\.{float}&|raw_int|: \stars&maybe\cr
\.{for}&|for_like|: \stars&maybe\cr
\.{fpos\_t}&|raw_int|: \stars&maybe\cr
\.{friend}&|int_like|: \stars&maybe\cr
\.{goto}&|case_like|: \stars&maybe\cr
\.{if}&|if_like|: \stars&maybe\cr
\.{ifdef}&|if_like|: \stars&maybe\cr
\.{ifndef}&|if_like|: \stars&maybe\cr
\.{imaginary}&|int_like|: \stars&maybe\cr
\.{include}&|if_like|: \stars&maybe\cr
\.{inline}&|int_like|: \stars&maybe\cr
\.{int}&|raw_int|: \stars&maybe\cr
\.{jmp\_buf}&|raw_int|: \stars&maybe\cr
\.{ldiv\_t}&|raw_int|: \stars&maybe\cr
\.{line}&|if_like|: \stars&maybe\cr
\.{long}&|raw_int|: \stars&maybe\cr
\.{make\_pair}&|ftemplate|: \.{\\\\\{make\\\_pair\}}&maybe\cr
\.{mutable}&|int_like|: \stars&maybe\cr
\.{namespace}&|struct_like|: \stars&maybe\cr
\.{new}&|new_like|: \stars&maybe\cr
\.{noexcept}&|attr|: \stars&maybe\cr
\.{not}&|alfop|: \stars&yes\cr
\.{not\_eq}&|alfop|: \stars&yes\cr
\.{NULL}&|exp|: \.{\\NULL}&yes\cr
\.{nullptr}&|exp|: \.{\\NULL}&yes\cr
\.{offsetof}&|raw_int|: \stars&maybe\cr
\.{operator}&|operator_like|: \stars&maybe\cr
\.{or}&|alfop|: \stars&yes\cr
\.{or\_eq}&|alfop|: \stars&yes\cr
\.{pragma}&|if_like|: \stars&maybe\cr
\.{private}&|public_like|: \stars&maybe\cr
\.{protected}&|public_like|: \stars&maybe\cr
\.{ptrdiff\_t}&|raw_int|: \stars&maybe\cr
\.{public}&|public_like|: \stars&maybe\cr
\.{register}&|int_like|: \stars&maybe\cr
\.{reinterpret\_cast}&|raw_int|: \stars&maybe\cr
\.{requires}&|int_like|: \stars&maybe\cr
\.{restrict}&|int_like|: \stars&maybe\cr
\.{return}&|case_like|: \stars&maybe\cr
\.{short}&|raw_int|: \stars&maybe\cr
\.{sig\_atomic\_t}&|raw_int|: \stars&maybe\cr
\.{signed}&|raw_int|: \stars&maybe\cr
\.{size\_t}&|raw_int|: \stars&maybe\cr
\.{sizeof}&|sizeof_like|: \stars&maybe\cr
\.{static}&|int_like|: \stars&maybe\cr
\.{static\_assert}&|sizeof_like|: \stars&maybe\cr
\.{static\_cast}&|raw_int|: \stars&maybe\cr
\.{struct}&|struct_like|: \stars&maybe\cr
\.{switch}&|for_like|: \stars&maybe\cr
\.{template}&|template_like|: \stars&maybe\cr
\.{TeX}&|exp|: \.{\\TeX}&yes\cr
\.{this}&|exp|: \.{\\this}&yes\cr
\.{thread\_local}&|raw_int|: \stars&maybe\cr
\.{throw}&|case_like|: \stars&maybe\cr
\.{time\_t}&|raw_int|: \stars&maybe\cr
\.{try}&|else_like|: \stars&maybe\cr
\.{typedef}&|typedef_like|: \stars&maybe\cr
\.{typeid}&|sizeof_like|: \stars&maybe\cr
\.{typename}&|struct_like|: \stars&maybe\cr
\.{undef}&|if_like|: \stars&maybe\cr
\.{union}&|struct_like|: \stars&maybe\cr
\.{unsigned}&|raw_int|: \stars&maybe\cr
\.{using}&|using_like|: \stars&maybe\cr
\.{va\_dcl}&|decl|: \stars&maybe\cr
\.{va\_list}&|raw_int|: \stars&maybe\cr
\.{virtual}&|int_like|: \stars&maybe\cr
\.{void}&|raw_int|: \stars&maybe\cr
\.{volatile}&|const_like|: \stars&maybe\cr
\.{wchar\_t}&|raw_int|: \stars&maybe\cr
\.{while}&|for_like|: \stars&maybe\cr
\.{xor}&|alfop|: \stars&yes\cr
\.{xor\_eq}&|alfop|: \stars&yes\cr
\.{@@,}&|insert|: \.{\\,}&maybe\cr
\.{@@\v}&|insert|: |opt| \.0&maybe\cr
\.{@@/}&|insert|: |force|&no\cr
\.{@@\#}&|insert|: |big_force|&no\cr
\.{@@+}&|insert|: |big_cancel| \.{\{\}} |break_space|
  \.{\{\}} |big_cancel|&no\cr
\.{@@;}&|semi|: &maybe\cr
\.{@@[@q]@>}&|begin_arg|: &maybe\cr
\.{@q[@>@@]}&|end_arg|: &maybe\cr
\.{@@\&}&|insert|: \.{\\J}&maybe\cr
\.{@@h}&|insert|: |force| \.{\\ATH} |force|&no\cr
\.{@@<}\thinspace section name\thinspace\.{@@>}&|section_scrap|:
 \.{\\X}$n$\.:translated section name\.{\\X}&maybe\cr
\.{@@(@q)@>}\thinspace section name\thinspace\.{@@>}&|section_scrap|:
 \.{\\X}$n$\.{:\\.\{}section name with special characters
      quoted\.{\ \}\\X}&maybe\cr
\.{/*}\thinspace comment\thinspace\.{*/}&|insert|: |cancel|
      \.{\\C\{}translated comment\.\} |force|&no\cr
\.{//}\thinspace comment&|insert|: |cancel|
      \.{\\SHC\{}translated comment\.\} |force|&no\cr
}

\smallskip
The construction \.{@@t}\thinspace stuff\/\thinspace\.{@@>} contributes
\.{\\hbox\{}\thinspace stuff\/\thinspace\.\} to the following scrap.

@i prod.w

@* Implementing the productions.
More specifically, a scrap is a structure consisting of a category
|cat| and a |text_pointer| |trans|, which points to the translation in
|tok_start|.  When \CEE/ text is to be processed with the grammar above,
we form an array |scrap_info| containing the initial scraps.
Our production rules have the nice property that the right-hand side is never
longer than the left-hand side. Therefore it is convenient to use sequential
allocation for the current sequence of scraps. Five pointers are used to
manage the parsing:

\yskip\hang |pp| is a pointer into |scrap_info|.  We will try to match
the category codes |pp->cat,@,@,(pp+1)->cat|$,\,\,\ldots\,$
to the left-hand sides of productions.

\yskip\hang |scrap_base|, |lo_ptr|, |hi_ptr|, and |scrap_ptr| are such that
the current sequence of scraps appears in positions |scrap_base| through
|lo_ptr| and |hi_ptr| through |scrap_ptr|, inclusive, in the |cat| and
|trans| arrays. Scraps located between |scrap_base| and |lo_ptr| have
been examined, while those in positions |>=hi_ptr| have not yet been
looked at by the parsing process.

\yskip\noindent Initially |scrap_ptr| is set to the position of the final
scrap to be parsed, and it doesn't change its value. The parsing process
makes sure that |lo_ptr>=pp+3|, since productions have as many as four terms,
by moving scraps from |hi_ptr| to |lo_ptr|. If there are
fewer than |pp+3| scraps left, the positions up to |pp+3| are filled with
blanks that will not match in any productions. Parsing stops when
|pp==lo_ptr+1| and |hi_ptr==scrap_ptr+1|.

Since the |scrap| structure will later be used for other purposes, we
declare its second element as a union.

@<Type...@>=
typedef struct {
  eight_bits cat;
  eight_bits mathness;
  union {
    text_pointer Trans;@+@t}\6{@>
    @<Rest of |trans_plus| union@>@;
  } trans_plus;
} scrap;
typedef scrap *scrap_pointer;

@ @d trans trans_plus.Trans /* translation texts of scraps */

@<Private...@>=
static scrap scrap_info[max_scraps]; /* memory array for scraps */
static scrap_pointer scrap_info_end=scrap_info+max_scraps-1; /* end of |scrap_info| */
static scrap_pointer scrap_base; /* beginning of the current scrap sequence */
static scrap_pointer scrap_ptr; /* ending of the current scrap sequence */
static scrap_pointer max_scr_ptr; /* largest value assumed by |scrap_ptr| */
static scrap_pointer pp; /* current position for reducing productions */
static scrap_pointer lo_ptr; /* last scrap that has been examined */
static scrap_pointer hi_ptr; /* first scrap that has not been examined */

@ @<Set init...@>=
scrap_base=scrap_info+1;
max_scr_ptr=scrap_ptr=scrap_info;

@ Token lists in |@!tok_mem| are composed of the following kinds of
items for \TEX/ output.

\yskip\item{$\bullet$}Character codes and special codes like |force| and
|math_rel| represent themselves;

\item{$\bullet$}|id_flag+p| represents \.{\\\\\{{\rm identifier $p$}\}};

\item{$\bullet$}|res_flag+p| represents \.{\\\&\{{\rm identifier $p$}\}};

\item{$\bullet$}|section_flag+p| represents section name |p|;

\item{$\bullet$}|tok_flag+p| represents token list number |p|;

\item{$\bullet$}|inner_tok_flag+p| represents token list number |p|, to be
translated without line-break controls.

@d id_flag 10240 /* signifies an identifier */
@d res_flag (2*id_flag) /* signifies a reserved word */
@d section_flag (3*id_flag) /* signifies a section name */
@d tok_flag (4*id_flag) /* signifies a token list */
@d inner_tok_flag (5*id_flag) /* signifies a token list in `\pb' */

@c
static void
print_text( /* prints a token list for debugging; not used in |main| */
text_pointer p)
{
  token_pointer j; /* index into |tok_mem| */
  sixteen_bits r; /* remainder of token after the flag has been stripped off */
  if (p>=text_ptr) printf("BAD");
  else for (j=*p; j<*(p+1); j++) {
    r=*j%id_flag;
    switch (*j) {
      case id_flag:
        printf("\\\\{"@q}@>); print_id((name_dir+r)); putchar(@q{@>'}');
        break;
      case res_flag:
        printf("\\&{"@q}@>); print_id((name_dir+r)); putchar(@q{@>'}');
        break;
      case section_flag:
        putchar('<'); print_section_name((name_dir+r)); putchar('>');
        break;
      case tok_flag: printf("[[%d]]",(int)r); break;
      case inner_tok_flag: printf("|[[%d]]|",(int)r); break;
      default: @<Print token |r| in symbolic form@>@;
    }
  }
  update_terminal;
}

@ @<Predecl...@>=@+static void print_text(text_pointer p);

@ @<Print token |r|...@>=
switch (r) {
  case math_rel: printf("\\mathrel{"@q}@>); break;
  case big_cancel: printf("[ccancel]"); break;
  case cancel: printf("[cancel]"); break;
  case indent: printf("[indent]"); break;
  case outdent: printf("[outdent]"); break;
  case dindent: printf("[dindent]"); break;
  case backup: printf("[backup]"); break;
  case opt: printf("[opt]"); break;
  case break_space: printf("[break]"); break;
  case force: printf("[force]"); break;
  case big_force: printf("[fforce]"); break;
  case preproc_line: printf("[preproc]"); break;
  case quoted_char: j++; printf("[%o]",(unsigned int)*j); break;
  case end_translation: printf("[quit]"); break;
  case inserted: printf("[inserted]"); break;
  default: putchar((int)r);
}

@ The production rules listed above are embedded directly into \.{CWEAVE},
since it is easier to do this than to write an interpretive system
that would handle production systems in general. Several macros are defined
here so that the program for each production is fairly short.

All of our productions conform to the general notion that some |k|
consecutive scraps starting at some position |j| are to be replaced by a
single scrap of some category |c| whose translation is composed from the
translations of the disappearing scraps. After this production has been
applied, the production pointer |pp| should change by an amount |d|. Such
a production can be represented by the quadruple |(j,k,c,d)|. For example,
the production `|exp@,comma@,exp| $\RA$ |exp|' would be represented by
`|(pp,3,exp,-2)|'; in this case the pointer |pp| should decrease by 2
after the production has been applied, because some productions with
|exp| in their second or third positions might now match,
but no productions have
|exp| in the fourth position of their left-hand sides. Note that
the value of |d| is determined by the whole collection of productions, not
by an individual one.
The determination of |d| has been
done by hand in each case, based on the full set of productions but not on
the grammar of \CEE/ or on the rules for constructing the initial
scraps.

We also attach a serial number to each production, so that additional
information is available when debugging. For example, the program below
contains the statement `|reduce(pp,3,exp,-2,4)|' when it implements
the production just mentioned.

Before calling |reduce|, the program should have appended the tokens of
the new translation to the |tok_mem| array. We commonly want to append
copies of several existing translations, and macros are defined to
simplify these common cases. For example, |big_app2(pp)| will append the
translations of two consecutive scraps, |pp->trans| and |(pp+1)->trans|, to
the current token list. If the entire new translation is formed in this
way, we write `|squash(j,k,c,d,n)|' instead of `|reduce(j,k,c,d,n)|'. For
example, `|squash(pp,3,exp,-2,3)|' is an abbreviation for `|big_app3(pp);
reduce(pp,3,exp,-2,3)|'.

A couple more words of explanation:
Both |big_app| and |app| append a token (while |big_app1| to |big_app4|
append the specified number of scrap translations) to the current token list.
The difference between |big_app| and |app| is simply that |big_app|
checks whether there can be a conflict between math and non-math
tokens, and intercalates a `\.{\$}' token if necessary.  When in
doubt what to use, use |big_app|.

The |mathness| is an attribute of scraps that says whether they are
to be printed in a math mode context or not.  It is separate from the
``part of speech'' (the |cat|) because to make each |cat| have
a fixed |mathness| (as in the original \.{WEAVE}) would multiply the
number of necessary production rules.

The low two bits (i.e., |mathness % 4|) control the left boundary.
(We need two bits because we allow cases |yes_math|, |no_math| and
|maybe_math|, which can go either way.)
The next two bits (i.e., |mathness / 4|) control the right boundary.
If we combine two scraps and the right boundary of the first has
a different mathness from the left boundary of the second, we
insert a \.{\$} in between.  Similarly, if at printing time some
irreducible scrap has a |yes_math| boundary the scrap gets preceded
or followed by a~\.{\$}. The left boundary is |maybe_math| if and
only if the right boundary is.

The code below is an exact translation of the production rules into
\CEE/, using such macros, and the reader should have no difficulty
understanding the format by comparing the code with the symbolic
productions as they were listed earlier.

@d no_math 2 /* should be in horizontal mode */
@d yes_math 1 /* should be in math mode */
@d maybe_math 0 /* works in either horizontal or math mode */
@d big_app2(a) big_app1(a);@+big_app1(a+1)
@d big_app3(a) big_app2(a);@+big_app1(a+2)
@d big_app4(a) big_app3(a);@+big_app1(a+3)
@d big_app1_insert(p,c) big_app1(p);@+big_app(c);@+big_app1(p+1)
@d app(a) *(tok_ptr++)=(token)(a)

@<Private...@>=
static int cur_mathness, init_mathness;

@ @<Predecl...@>=
static void app_str(const char *);@/
static void big_app(token);@/
static void big_app1(scrap_pointer);

@ @c
static void
app_str(
const char *s)
{
  while (*s) app_tok(*s++);
}

static void
big_app(
token a)
{
        if (a==' ' || (a>=big_cancel && a<=big_force) || a==dindent)
            /* non-math token */ {
                if (cur_mathness==maybe_math) init_mathness=no_math;
                else if (cur_mathness==yes_math) app_str("{}$");
                cur_mathness=no_math;
        } else {
                if (cur_mathness==maybe_math) init_mathness=yes_math;
                else if (cur_mathness==no_math) app_str("${}");
                cur_mathness=yes_math;
        }
        app(a);
}

static void
big_app1(
scrap_pointer a)
{
  switch (a->mathness % 4) { /* left boundary */
  case (no_math):
    if (cur_mathness==maybe_math) init_mathness=no_math;
    else if (cur_mathness==yes_math) app_str("{}$");
    cur_mathness=a->mathness / 4; /* right boundary */
    break;
  case (yes_math):
    if (cur_mathness==maybe_math) init_mathness=yes_math;
    else if (cur_mathness==no_math) app_str("${}");
    cur_mathness=a->mathness / 4; /* right boundary */
    break;
  case (maybe_math): /* no changes */ break;
  }
  app(tok_flag+(int)((a)->trans-tok_start));
}

@ Let us consider the big switch for productions now, before looking
at its context. We want to design the program so that this switch
works, so we might as well not keep ourselves in suspense about exactly what
code needs to be provided with a proper environment.

@d cat1 (pp+1)->cat
@d cat2 (pp+2)->cat
@d cat3 (pp+3)->cat
@d lhs_not_simple (pp->cat!=public_like
        && pp->cat!=semi
        && pp->cat!=prelangle
        && pp->cat!=prerangle @|
        && pp->cat!=template_like
        && pp->cat!=new_like
        && pp->cat!=new_exp
        && pp->cat!=ftemplate @|
        && pp->cat!=raw_ubin
        && pp->cat!=const_like
        && pp->cat!=raw_int
        && pp->cat!=operator_like)
 /* not a production with left side length 1 */

@<Match a production at |pp|, or increase |pp| if there is no match@>=
if (cat1==end_arg && lhs_not_simple)
  if (pp->cat==begin_arg) squash(pp,2,exp,-2,124);
  else squash(pp,2,end_arg,-1,125);
else if (pp->cat==rbrack) reduce(pp,0,rpar,-3,130);
else if (pp->cat==using_like) reduce(pp,0,int_like,-3,140);
else if (cat1==insert) squash(pp,2,pp->cat,-2,0);
else if (cat2==insert) squash(pp+1,2,(pp+1)->cat,-1,0);
else if (cat3==insert) squash(pp+2,2,(pp+2)->cat,0,0);
else
  switch (pp->cat) {
    case exp: @<Cases for |exp|@>@; @+break;
    case lpar: @<Cases for |lpar|@>@; @+break;
    case unop: @<Cases for |unop|@>@; @+break;
    case ubinop: @<Cases for |ubinop|@>@; @+break;
    case binop: @<Cases for |binop|@>@; @+break;
    case cast: @<Cases for |cast|@>@; @+break;
    case sizeof_like: @<Cases for |sizeof_like|@>@; @+break;
    case int_like: @<Cases for |int_like|@>@; @+break;
    case public_like: @<Cases for |public_like|@>@; @+break;
    case colcol: @<Cases for |colcol|@>@; @+break;
    case decl_head: @<Cases for |decl_head|@>@; @+break;
    case decl: @<Cases for |decl|@>@; @+break;
    case base: @<Cases for |base|@>@; @+break;
    case struct_like: @<Cases for |struct_like|@>@; @+break;
    case struct_head: @<Cases for |struct_head|@>@; @+break;
    case fn_decl: @<Cases for |fn_decl|@>@; @+break;
    case function: @<Cases for |function|@>@; @+break;
    case lbrace: @<Cases for |lbrace|@>@; @+break;
    case if_like: @<Cases for |if_like|@>@; @+break;
    case else_like: @<Cases for |else_like|@>@; @+break;
    case else_head: @<Cases for |else_head|@>@; @+break;
    case if_clause: @<Cases for |if_clause|@>@; @+break;
    case if_head: @<Cases for |if_head|@>@; @+break;
    case do_like: @<Cases for |do_like|@>@; @+break;
    case case_like: @<Cases for |case_like|@>@; @+break;
    case catch_like: @<Cases for |catch_like|@>@; @+break;
    case tag: @<Cases for |tag|@>@; @+break;
    case stmt: @<Cases for |stmt|@>@; @+break;
    case semi: @<Cases for |semi|@>@; @+break;
    case lproc: @<Cases for |lproc|@>@; @+break;
    case section_scrap: @<Cases for |section_scrap|@>@; @+break;
    case insert: @<Cases for |insert|@>@; @+break;
    case prelangle: @<Cases for |prelangle|@>@; @+break;
    case prerangle: @<Cases for |prerangle|@>@; @+break;
    case langle: @<Cases for |langle|@>@; @+break;
    case template_like: @<Cases for |template_like|@>@; @+break;
    case new_like: @<Cases for |new_like|@>@; @+break;
    case new_exp: @<Cases for |new_exp|@>@; @+break;
    case ftemplate: @<Cases for |ftemplate|@>@; @+break;
    case for_like: @<Cases for |for_like|@>@; @+break;
    case raw_ubin: @<Cases for |raw_ubin|@>@; @+break;
    case const_like: @<Cases for |const_like|@>@; @+break;
    case raw_int: @<Cases for |raw_int|@>@; @+break;
    case operator_like: @<Cases for |operator_like|@>@; @+break;
    case typedef_like: @<Cases for |typedef_like|@>@; @+break;
    case delete_like: @<Cases for |delete_like|@>@; @+break;
    case question: @<Cases for |question|@>@; @+break;
    case alignas_like: @<Cases for |alignas_like|@>@; @+break;
    case lbrack: @<Cases for |lbrack|@>@; @+break;
    case attr_head: @<Cases for |attr_head|@>@; @+break;
    case attr: @<Cases for |attr|@>@; @+break;
    case default_like: @<Cases for |default_like|@>@; @+break;
  }
pp++; /* if no match was found, we move to the right */

@ In \CEE/, new specifier names can be defined via |typedef|, and we want
to make the parser recognize future occurrences of the identifier thus
defined as specifiers.  This is done by the procedure |make_reserved|,
which changes the |ilk| of the relevant identifier.

We first need a procedure to recursively seek the first
identifier in a token list, because the identifier might
be enclosed in parentheses, as when one defines a function
returning a pointer.

If the first identifier found is a keyword like `\&{case}', we
return the special value |case_found|; this prevents underlining
of identifiers in case labels.

If the first identifier is the keyword `\&{operator}', we give up;
users who want to index definitions of overloaded \CPLUSPLUS/ operators
should say, for example, `\.{@@!@@\^\\\&\{operator\} \$+\{=\}\$@@>}' (or,
more properly alpha\-betized,
`\.{@@!@@:operator+=\}\{\\\&\{operator\} \$+\{=\}\$@@>}').

@d no_ident_found (token_pointer)0 /* distinct from any identifier token */
@d case_found (token_pointer)1 /* likewise */
@d operator_found (token_pointer)2 /* likewise */

@<Predecl...@>=
static token_pointer find_first_ident(text_pointer);@/
static void make_reserved(scrap_pointer);@/
static void make_underlined(scrap_pointer);@/
static void underline_xref(name_pointer);

@ @c
static token_pointer
find_first_ident(
text_pointer p)
{
  token_pointer q; /* token to be returned */
  token_pointer j; /* token being looked at */
  sixteen_bits r; /* remainder of token after the flag has been stripped off */
  if (p>=text_ptr) confusion("find_first_ident");
  for (j=*p; j<*(p+1); j++) {
    r=*j%id_flag;
    switch (*j/id_flag) {
      case 2: /* |res_flag| */
        if (name_dir[r].ilk==case_like) return case_found;
        if (name_dir[r].ilk==operator_like) return operator_found;
        if (name_dir[r].ilk!=raw_int) break;
      case 1: return j;
      case 4: case 5: /* |tok_flag| or |inner_tok_flag| */
        if ((q=find_first_ident(tok_start+r))!=no_ident_found)
          return q;
      default: ; /* char, |section_flag|, fall thru: move on to next token */
        if (*j==inserted) return no_ident_found; /* ignore inserts */
        else if (*j==qualifier) j++; /* bypass namespace qualifier */
    }
  }
  return no_ident_found;
}

@ The scraps currently being parsed must be inspected for any
occurrence of the identifier that we're making reserved; hence
the |for| loop below.

@c
static void
make_reserved( /* make the first identifier in |p->trans| like |int| */
scrap_pointer p)
{
  sixteen_bits tok_value; /* the name of this identifier, plus its flag */
  token_pointer tok_loc; /* pointer to |tok_value| */
  if ((tok_loc=find_first_ident(p->trans))<=operator_found)
    return; /* this should not happen */
  tok_value=*tok_loc;
  for (;p<=scrap_ptr; p==lo_ptr? p=hi_ptr: p++)
    if (p->cat==exp)
      if (**(p->trans)==tok_value) {
        p->cat=raw_int;
        **(p->trans)=tok_value%id_flag+res_flag;
      }
  (name_dir+(sixteen_bits)(tok_value%id_flag))->ilk=raw_int;
  *tok_loc=tok_value%id_flag+res_flag;
}

@ In the following situations we want to mark the occurrence of
an identifier as a definition: when |make_reserved| is just about to be
used; after a specifier, as in |char **argv|;
before a colon, as in \\{found}:; and in the declaration of a function,
as in \\{main}()$\{\ldots;\}$.  This is accomplished by the invocation
of |make_underlined| at appropriate times.  Notice that, in the declaration
of a function, we find out that the identifier is being defined only after
it has been swallowed up by an |exp|.

@c
static void
make_underlined(
/* underline the entry for the first identifier in |p->trans| */
scrap_pointer p)
{
  token_pointer tok_loc; /* where the first identifier appears */
  if ((tok_loc=find_first_ident(p->trans))<=operator_found)
    return; /* this happens, for example, in |case found:| */
  xref_switch=def_flag;
  underline_xref(*tok_loc%id_flag+name_dir);
}

@ We cannot use |new_xref| to underline a cross-reference at this point
because this would just make a new cross-reference at the end of the list.
We actually have to search through the list for the existing
cross-reference.

@c
static void
underline_xref(
name_pointer p)
{
  xref_pointer q=(xref_pointer)p->xref; /* pointer to cross-reference being examined */
  xref_pointer r; /* temporary pointer for permuting cross-references */
  sixteen_bits m; /* cross-reference value to be installed */
  sixteen_bits n; /* cross-reference value being examined */
  if (no_xref) return;
  m=section_count+xref_switch;
  while (q != xmem) {
    n=q->num;
    if (n==m) return;
    else if (m==n+def_flag) {
        q->num=m; return;
    }
    else if (n>=def_flag && n<m) break;
    q=q->xlink;
  }
  @<Insert new cross-reference at |q|, not at beginning of list@>@;
}

@ We get to this section only when the identifier is one letter long,
so it didn't get a non-underlined entry during phase one.  But it may
have got some explicitly underlined entries in later sections, so in order
to preserve the numerical order of the entries in the index, we have
to insert the new cross-reference not at the beginning of the list
(namely, at |p->xref|), but rather right before |q|.

@<Insert new cross-reference at |q|...@>=
append_xref(0); /* this number doesn't matter */
xref_ptr->xlink=(xref_pointer)p->xref; r=xref_ptr;
update_node(p);
while (r->xlink!=q) {r->num=r->xlink->num; r=r->xlink;}
r->num=m; /* everything from |q| on is left undisturbed */

@ Now comes the code that tries to match each production starting
with a particular type of scrap. Whenever a match is discovered,
the |squash| or |reduce| function will cause the appropriate action
to be performed.

@<Cases for |exp|@>=
if (cat1==lbrace || cat1==int_like || cat1==decl) {
  make_underlined(pp); big_app1(pp); big_app(dindent);
  reduce(pp,1,fn_decl,0,1);
}
else if (cat1==unop) squash(pp,2,exp,-2,2);
else if ((cat1==binop || cat1==ubinop) && cat2==exp)
        squash(pp,3,exp,-2,3);
else if (cat1==comma && cat2==exp) {
  big_app2(pp);
  app(opt); app('9'); big_app1(pp+2); reduce(pp,3,exp,-2,4);
}
else if (cat1==lpar && cat2==rpar && cat3==colon) reduce(pp+3,0,base,0,5);
else if (cat1==cast && cat2==colon) reduce(pp+2,0,base,0,5);
else if (cat1==semi) squash(pp,2,stmt,-1,6);
else if (cat1==colon) {
  make_underlined (pp); squash(pp,2,tag,-1,7);
}
else if (cat1==rbrace) reduce(pp,0,stmt,-1,8);
else if (cat1==lpar && cat2==rpar && (cat3==const_like || cat3==case_like)) {
  big_app1_insert(pp+2,' '); reduce(pp+2,2,rpar,0,9);
}
else if (cat1==cast && (cat2==const_like || cat2==case_like)) {
  big_app1_insert(pp+1,' '); reduce(pp+1,2,cast,0,9);
}
else if (cat1==exp || cat1==cast) squash(pp,2,exp,-2,10);
else if (cat1==attr) {
  big_app1_insert(pp,' '); reduce(pp,2,exp,-2,142);
}
else if (cat1==colcol && cat2==int_like) squash(pp,3,int_like,-2,152);

@ @<Cases for |lpar|@>=
if ((cat1==exp||cat1==ubinop) && cat2==rpar) squash(pp,3,exp,-2,11);
else if (cat1==rpar) {
  big_app1(pp); app_str("\\,"); big_app1(pp+1);
@.\\,@>
  reduce(pp,2,exp,-2,12);
}
else if ((cat1==decl_head || cat1==int_like || cat1==cast) && cat2==rpar)
 squash(pp,3,cast,-2,13);
else if ((cat1==decl_head || cat1==int_like || cat1==exp) && cat2==comma) {
  big_app3(pp); app(opt); app('9'); reduce(pp,3,lpar,-1,14);
}
else if (cat1==stmt || cat1==decl) {
  big_app2(pp); big_app(' '); reduce(pp,2,lpar,-1,15);
}

@ @<Cases for |unop|@>=
if (cat1==exp || cat1==int_like) squash(pp,2,exp,-2,16);

@ @<Cases for |ubinop|@>=
if (cat1==cast && cat2==rpar) {
  big_app('{'); big_app1_insert(pp,'}'); reduce(pp,2,cast,-2,17);
}
else if (cat1==exp || cat1==int_like) {
  big_app('{'); big_app1_insert(pp,'}'); reduce(pp,2,cat1,-2,18);
}
else if (cat1==binop) {
  big_app(math_rel); big_app1_insert(pp,'{'); big_app('}');
  big_app('}'); reduce(pp,2,binop,-1,19);
}

@ @<Cases for |binop|@>=
if (cat1==binop) {
  big_app(math_rel); big_app('{'); big_app1(pp); big_app('}');
  big_app('{'); big_app1(pp+1); big_app('}');
  big_app('}'); reduce(pp,2,binop,-1,20);
}

@ @<Cases for |cast|@>=
if (cat1==lpar) squash(pp,2,lpar,-1,21);
else if (cat1==exp) {
  big_app1_insert(pp,' '); reduce(pp,2,exp,-2,21);
}
else if (cat1==semi) reduce(pp,0,exp,-2,22);

@ @<Cases for |sizeof_like|@>=
if (cat1==cast) squash(pp,2,exp,-2,23);
else if (cat1==exp) {
  big_app1_insert(pp,' '); reduce(pp,2,exp,-2,24);
}

@ @<Cases for |int_like|@>=
if (cat1==int_like|| cat1==struct_like) {
  big_app1_insert(pp,' '); reduce(pp,2,cat1,-2,25);
}
else if (cat1==exp && (cat2==raw_int||cat2==struct_like))
  squash(pp,2,int_like,-2,26);
else if (cat1==exp || cat1==ubinop || cat1==colon) {
  big_app1(pp); big_app(' '); reduce(pp,1,decl_head,-1,27);
}
else if (cat1==semi || cat1==binop) reduce(pp,0,decl_head,0,28);

@ @<Cases for |public_like|@>=
if (cat1==colon) squash(pp,2,tag,-1,29);
else reduce(pp,0,int_like,-2,30);

@ @<Cases for |colcol|@>=
if (cat1==exp||cat1==int_like) {
  app(qualifier); squash(pp,2,cat1,-2,31);
}
else if (cat1==colcol) squash(pp,2,colcol,-1,32);

@ @<Cases for |decl_head|@>=
if (cat1==comma) {
  big_app2(pp); big_app(' '); reduce(pp,2,decl_head,-1,33);
}
else if (cat1==ubinop) {
  big_app1_insert(pp,'{'); big_app('}'); reduce(pp,2,decl_head,-1,34);
}
else if (cat1==exp && cat2!=lpar && cat2!=lbrack && cat2!=exp && cat2!=cast) {
  make_underlined(pp+1); squash(pp,2,decl_head,-1,35);
}
else if ((cat1==binop||cat1==colon) && cat2==exp && (cat3==comma ||
    cat3==semi || cat3==rpar))
  squash(pp,3,decl_head,-1,36);
else if (cat1==cast) squash(pp,2,decl_head,-1,37);
else if (cat1==lbrace || cat1==int_like || cat1==decl) {
  big_app(dindent); squash(pp,1,fn_decl,0,38);
}
else if (cat1==semi) squash(pp,2,decl,-1,39);
else if (cat1==attr) {
  big_app1_insert(pp,' '); reduce(pp,2,decl_head,-1,139);
}

@ @<Cases for |decl|@>=
if (cat1==decl) {
  big_app1_insert(pp,force); reduce(pp,2,decl,-1,40);
}
else if (cat1==stmt || cat1==function) {
  big_app1_insert(pp,big_force); reduce(pp,2,cat1,-1,41);
}

@ @<Cases for |base|@>=
if (cat1==int_like || cat1==exp) {
  if (cat2==comma) {
    big_app1(pp); big_app(' '); big_app2(pp+1);
    app(opt); app('9'); reduce(pp,3,base,0,42);
  }
  else if (cat2==lbrace) {
    big_app1_insert(pp,' '); big_app(' '); big_app1(pp+2);
    reduce(pp,3,lbrace,-2,43);
  }
}

@ @<Cases for |struct_like|@>=
if (cat1==lbrace) {
  big_app1_insert(pp,' '); reduce(pp,2,struct_head,0,44);
}
else if (cat1==exp||cat1==int_like) {
  if (cat2==lbrace || cat2==semi) {
    make_underlined(pp+1); make_reserved(pp+1);
    big_app1_insert(pp,' ');
    if (cat2==semi) reduce(pp,2,decl_head,0,45);
    else {
      big_app(' '); big_app1(pp+2);reduce(pp,3,struct_head,0,46);
    }
  }
  else if (cat2==colon) reduce(pp+2,0,base,2,47);
  else if (cat2!=base) {
    big_app1_insert(pp,' '); reduce(pp,2,int_like,-2,48);
  }
}
else if (cat1==attr) {
  big_app1_insert(pp,' '); reduce(pp,2,struct_like,-3,141);
}
else if (cat1==struct_like) {
  big_app1_insert(pp,' '); reduce(pp,2,struct_like,-3,151);
}

@ @<Cases for |struct_head|@>=
if ((cat1==decl || cat1==stmt || cat1==function) && cat2==rbrace) {
  big_app1(pp); big_app(indent); big_app(force); big_app1(pp+1);
  big_app(outdent); big_app(force); big_app1(pp+2);
  reduce(pp,3,int_like,-2,49);
}
else if (cat1==rbrace) {
  big_app1(pp); app_str("\\,"); big_app1(pp+1);
@.\\,@>
  reduce(pp,2,int_like,-2,50);
}

@ @<Cases for |fn_decl|@>=
if (cat1==decl) {
  big_app1_insert(pp,force); reduce(pp,2,fn_decl,0,51);
}
else if (cat1==stmt) {
  big_app1(pp); app(outdent); app(outdent); big_app(force);
  big_app1(pp+1); reduce(pp,2,function,-1,52);
}
else if (cat1==attr) {
  big_app1_insert(pp,' '); reduce(pp,2,fn_decl,0,157);
}

@ @<Cases for |function|@>=
if (cat1==function || cat1==decl || cat1==stmt) {
  big_app1_insert(pp,big_force); reduce(pp,2,cat1,-1,53);
}

@ @<Cases for |lbrace|@>=
if (cat1==rbrace) {
  big_app1(pp); app_str("\\,"); big_app1(pp+1);
@.\\,@>
  reduce(pp,2,stmt,-1,54);
}
else if ((cat1==stmt||cat1==decl||cat1==function) && cat2==rbrace) {
  big_app(force); big_app1(pp); big_app(indent); big_app(force);
  big_app1(pp+1); big_app(force); big_app(backup); big_app1(pp+2);
  big_app(outdent); big_app(force); reduce(pp,3,stmt,-1,55);
}
else if (cat1==exp) {
  if (cat2==rbrace) squash(pp,3,exp,-2,56);
  else if (cat2==comma && cat3==rbrace) squash(pp,4,exp,-2,56);
}

@ @<Cases for |if_like|@>=
if (cat1==exp) {
  big_app1_insert(pp,' '); reduce(pp,2,if_clause,0,57);
}

@ @<Cases for |else_like|@>=
if (cat1==colon) reduce(pp+1,0,base,1,58);
else if (cat1==lbrace) reduce(pp,0,else_head,0,59);
else if (cat1==stmt) {
  big_app(force); big_app1(pp); big_app(indent); big_app(break_space);
  big_app1(pp+1); big_app(outdent); big_app(force);
  reduce(pp,2,stmt,-1,60);
}

@ @<Cases for |else_head|@>=
if (cat1==stmt || cat1==exp) {
  big_app(force); big_app1(pp); big_app(break_space); app(noop);
  big_app(cancel); big_app1(pp+1); big_app(force);
  reduce(pp,2,stmt,-1,61);
}

@ @<Cases for |if_clause|@>=
if (cat1==lbrace) reduce(pp,0,if_head,0,62);
else if (cat1==stmt) {
  if (cat2==else_like) {
    big_app(force); big_app1(pp); big_app(indent); big_app(break_space);
    big_app1(pp+1); big_app(outdent); big_app(force); big_app1(pp+2);
    if (cat3==if_like) {
      big_app(' '); big_app1(pp+3); reduce(pp,4,if_like,0,63);
    }
    else reduce(pp,3,else_like,0,64);
  }
  else reduce(pp,0,else_like,0,65);
}
else if (cat1==attr) {
  big_app1_insert(pp,' '); reduce(pp,2,if_head,0,146);
}

@ @<Cases for |if_head|@>=
if (cat1==stmt || cat1==exp) {
  if (cat2==else_like) {
    big_app(force); big_app1(pp); big_app(break_space); app(noop);
    big_app(cancel); big_app1_insert(pp+1,force);
    if (cat3==if_like) {
      big_app(' '); big_app1(pp+3); reduce(pp,4,if_like,0,66);
    }
    else reduce(pp,3,else_like,0,67);
  }
  else reduce(pp,0,else_head,0,68);
}

@ @<Cases for |do_like|@>=
if (cat1==stmt && cat2==else_like && cat3==semi) {
  big_app1(pp); big_app(break_space); app(noop); big_app(cancel);
  big_app1(pp+1); big_app(cancel); app(noop); big_app(break_space);
  big_app2(pp+2); reduce(pp,4,stmt,-1,69);
}

@ @<Cases for |case_like|@>=
if (cat1==semi) squash(pp,2,stmt,-1,70);
else if (cat1==colon) squash(pp,2,tag,-1,71);
else if (cat1==exp) {
  big_app1_insert(pp,' '); reduce(pp,2,exp,-2,72);
}

@ @<Cases for |catch_like|@>=
if (cat1==cast || cat1==exp) {
  big_app1_insert(pp,dindent); reduce(pp,2,fn_decl,0,73);
}

@ @<Cases for |tag|@>=
if (cat1==tag) {
  big_app1_insert(pp,break_space); reduce(pp,2,tag,-1,74);
}
else if (cat1==stmt||cat1==decl||cat1==function) {
  big_app(force); big_app(backup); big_app1_insert(pp,break_space);
  reduce(pp,2,cat1,-1,75);
}
else if (cat1==rbrace) reduce(pp,0,decl,-1,156);

@ The user can decide at run-time whether short statements should be
grouped together on the same line.

@d force_lines flags['f'] /* should each statement be on its own line? */

@<Set init...@>=
force_lines=true;

@ @<Cases for |stmt|@>=
if (cat1==stmt||cat1==decl||cat1==function) {
  big_app1_insert(pp, (cat1==function || cat1==decl) ? big_force :
     force_lines ? force : break_space); reduce(pp,2,cat1,-1,76);
}

@ @<Cases for |semi|@>=
big_app(' '); squash(pp,1,stmt,-1,77);

@ @<Cases for |lproc|@>=
if (cat1==define_like) make_underlined(pp+2);
if (cat1==else_like || cat1==if_like || cat1==define_like)
  squash(pp,2,lproc,0,78);
else if (cat1==rproc) {
  app(inserted); squash(pp,2,insert,-1,79);
} else if (cat1==exp || cat1==function) {
  if (cat2==rproc) {
    app(inserted); big_app1(pp); big_app(' '); big_app2(pp+1);
    reduce(pp,3,insert,-1,80);
  }
  else if (cat1==exp && cat2==exp && cat3==rproc) {
    app(inserted); big_app1_insert(pp,' '); app_str("\\5");
@.\\5@>
    big_app2(pp+2); reduce(pp,4,insert,-1,80);
  }
}

@ @<Cases for |section_scrap|@>=
if (cat1==semi) {
  big_app2(pp); big_app(force); reduce(pp,2,stmt,-2,81);
}
else reduce(pp,0,exp,-2,82);

@ @<Cases for |insert|@>=
if (cat1)
  squash(pp,2,cat1,0,83);

@ @<Cases for |prelangle|@>=
init_mathness=cur_mathness=yes_math;
app('<'); reduce(pp,1,binop,-2,84);

@ @<Cases for |prerangle|@>=
init_mathness=cur_mathness=yes_math;
app('>'); reduce(pp,1,binop,-2,85);

@ @d reserve_typenames flags['t']
  /* should we treat \&{typename} in a template like \&{typedef}? */

@<Cases for |langle|@>=
if (cat1==prerangle) {
  big_app1(pp); app_str("\\,"); big_app1(pp+1);
@.\\,@>
  reduce(pp,2,cast,-1,86);
}
else if (cat1==decl_head || cat1==int_like || cat1==exp) {
  if (cat2==prerangle) squash(pp,3,cast,-1,87);
  else if (cat2==comma) {
    big_app3(pp); app(opt); app('9'); reduce(pp,3,langle,0,88);
  }
}
else if ((cat1==struct_like) @|
  && (cat2==exp || cat2==int_like) @|
  && (cat3==comma || cat3==prerangle)) {
    make_underlined(pp+2); if (reserve_typenames) make_reserved(pp+2);
    big_app2(pp); big_app(' '); big_app2(pp+2);
    if (cat3==comma) reduce(pp,4,langle,0,153);
    else reduce(pp,4,cast,-1,154);
  }

@ @<Cases for |template_like|@>=
if (cat1==exp && cat2==prelangle) reduce(pp+2,0,langle,2,89);
else if (cat1==exp || cat1==raw_int) {
  big_app1_insert(pp,' '); reduce(pp,2,cat1,-2,90);
}
else if (cat1==cast && cat2==struct_like) {
  big_app1_insert(pp,' '); reduce(pp,2,struct_like,0,155);
}
else reduce(pp,0,raw_int,0,91);

@ @<Cases for |new_like|@>=
if (cat1==lpar && cat2==exp && cat3==rpar) squash(pp,4,new_like,0,92);
else if (cat1==cast) {
  big_app1_insert(pp,' '); reduce(pp,2,exp,-2,93);
}
else if (cat1!=lpar) reduce(pp,0,new_exp,0,94);

@ @<Cases for |new_exp|@>=
if (cat1==int_like || cat1==const_like) {
  big_app1_insert(pp,' '); reduce(pp,2,new_exp,0,95);
}
else if (cat1==struct_like && (cat2==exp || cat2==int_like)) {
  big_app1_insert(pp,' '); big_app(' ');
  big_app1(pp+2); reduce(pp,3,new_exp,0,96);
}
else if (cat1==raw_ubin) {
  big_app1_insert(pp,'{'); big_app('}'); reduce(pp,2,new_exp,0,97);
}
else if (cat1==lpar) reduce(pp,0,exp,-2,98);
else if (cat1==exp) {
  big_app1(pp); big_app(' '); reduce(pp,1,exp,-2,98);
}
else if (cat1!=raw_int && cat1!=struct_like && cat1!=colcol)
  reduce(pp,0,exp,-2,99);

@ @<Cases for |ftemplate|@>=
if (cat1==prelangle) reduce(pp+1,0,langle,1,100);
else reduce(pp,0,exp,-2,101);

@ @<Cases for |for_like|@>=
if (cat1==exp) {
  big_app1_insert(pp,' '); reduce(pp,2,else_like,-2,102);
}

@ @<Cases for |raw_ubin|@>=
if (cat1==const_like) {
  big_app2(pp); app_str("\\ "); reduce(pp,2,raw_ubin,0,103);
@.\\\ @>
}
else reduce(pp,0,ubinop,-2,104);

@ @<Cases for |const_like|@>=
reduce(pp,0,int_like,-2,105);

@ @<Cases for |raw_int|@>=
if (cat1==prelangle) reduce(pp+1,0,langle,1,106);
else if (cat1==colcol) squash(pp,2,colcol,-1,107);
else if (cat1==cast) squash(pp,2,raw_int,0,108);
else if (cat1==lpar) reduce(pp,0,exp,-2,109);
else if (cat1==lbrack) reduce(pp,0,exp,-2,144);
else if (cat1!=langle) reduce(pp,0,int_like,-3,110);

@ @<Cases for |operator_like|@>=
if (cat1==binop || cat1==unop || cat1==ubinop) {
  if (cat2==binop) break;
  big_app1_insert(pp,'{'); big_app('}'); reduce(pp,2,exp,-2,111);
}
else if (cat1==new_like || cat1==delete_like) {
  big_app1_insert(pp,' '); reduce(pp,2,exp,-2,112);
}
else if (cat1==comma) squash(pp,2,exp,-2,113);
else if (cat1!=raw_ubin) reduce(pp,0,new_exp,0,114);

@ @<Cases for |typedef_like|@>=
if ((cat1==int_like || cat1==cast) && (cat2==comma || cat2==semi))
  reduce(pp+1,0,exp,-1,115);
else if (cat1==int_like) {
  big_app1_insert(pp,' '); reduce(pp,2,typedef_like,0,116);
}
else if (cat1==exp && cat2!=lpar && cat2!=exp && cat2!=cast) {
  make_underlined(pp+1); make_reserved(pp+1);
  big_app1_insert(pp,' '); reduce(pp,2,typedef_like,0,117);
}
else if (cat1==comma) {
  big_app2(pp); big_app(' '); reduce(pp,2,typedef_like,0,118);
}
else if (cat1==semi) squash(pp,2,decl,-1,119);
else if (cat1==ubinop && (cat2==ubinop || cat2==cast)) {
  big_app('{'); big_app1_insert(pp+1,'}'); reduce(pp+1,2,cat2,0,120);
}

@ @<Cases for |delete_like|@>=
if (cat1==lpar && cat2==rpar) {
  big_app2(pp); app_str("\\,"); big_app1(pp+2);
@.\\,@>
  reduce(pp,3,delete_like,0,121);
}
else if (cat1==exp) {
  big_app1_insert(pp,' '); reduce(pp,2,exp,-2,122);
}

@ @<Cases for |question|@>=
if (cat1==exp && (cat2==colon || cat2==base)) {
  (pp+2)->mathness=5*yes_math; /* this colon should be in math mode */
  squash(pp,3,binop,-2,123);
}

@ @<Cases for |alignas_like|@>=
if (cat1==decl_head) squash(pp,2,attr,-1,126);
else if (cat1==exp) squash(pp,2,attr,-1,127);
else if (cat1==cast) squash(pp,2,attr,-1,158);

@ @<Cases for |lbrack|@>=
if (cat1==lbrack)
  if (cat2==rbrack && cat3==rbrack) squash(pp,4,exp,-2,147);
  else squash(pp,2,attr_head,-1,128);
else reduce(pp,0,lpar,-1,129);

@ @<Cases for |attr_head|@>=
if (cat1==rbrack && cat2==rbrack) squash(pp,3,attr,-1,131);
else if (cat1==exp) squash(pp,2,attr_head,0,132);
else if (cat1==using_like && cat2==exp && cat3==colon) {
  big_app2(pp); big_app(' '); big_app2(pp+2); big_app(' ');
  reduce(pp,4,attr_head,0,133);
}
else if (cat1==comma) squash(pp,2,attr_head,0,145);

@ @<Cases for |attr|@>=
if (cat1==lbrace || cat1==stmt) {
  big_app1_insert(pp,' '); reduce(pp,2,cat1,-2,134);
}
else if (cat1==tag) {
  big_app1_insert(pp,' '); reduce(pp,2,tag,-1,135);
}
else if (cat1==semi) squash(pp,2,stmt,-2,136);
else if (cat1==attr) {
  big_app1_insert(pp,' '); reduce(pp,2,attr,-1,137);
}
else if (cat1==decl_head) {
  big_app1_insert(pp,' '); reduce(pp,2,decl_head,-1,138);
}
else if (cat1==typedef_like) {
  big_app1_insert(pp,' '); reduce(pp,2,typedef_like,0,143);
}
else if (cat1==function) {
  big_app1_insert(pp,' '); reduce(pp,2,function,-1,148);
}

@ @<Cases for |default_like|@>=
if (cat1==colon) reduce(pp,0,case_like,-3,149);
else reduce(pp,0,exp,-2,150);

@ The `|freeze_text|' macro is used to give official status to a token list.
Before saying |freeze_text|, items are appended to the current token list,
and we know that the eventual number of this token list will be the current
value of |text_ptr|. But no list of that number really exists as yet,
because no ending point for the current list has been
stored in the |tok_start| array. After saying |freeze_text|, the
old current token list becomes legitimate, and its number is the current
value of |text_ptr-1| since |text_ptr| has been increased. The new
current token list is empty and ready to be appended~to.
Note that |freeze_text| does not check to see that |text_ptr| hasn't gotten
too large, since it is assumed that this test was done beforehand.

@d freeze_text *(++text_ptr)=tok_ptr

@<Predecl...@>=
static void reduce(scrap_pointer,short,eight_bits,short,short);@/
static void squash(scrap_pointer,short,eight_bits,short,short);

@ Now here's the |reduce| procedure used in our code for productions,
which takes advantage of the simplification that occurs when |k==0|.

@c
static void
reduce(
scrap_pointer j, short k,
eight_bits c,
short d, short n)
{
  scrap_pointer i, i1; /* pointers into scrap memory */
  j->cat=c;
  if (k>0) {
    j->trans=text_ptr;
    j->mathness=4*cur_mathness+init_mathness;
    freeze_text;
  }
  if (k>1) {
    for (i=j+k, i1=j+1; i<=lo_ptr; i++, i1++) {
      i1->cat=i->cat; i1->trans=i->trans;
      i1->mathness=i->mathness;
    }
    lo_ptr=lo_ptr-k+1;
  }
  pp=(pp+d<scrap_base? scrap_base: pp+d);
  @<Print a snapshot of the scrap list if debugging @>@;
  pp--; /* we next say |pp++| */
}

@ And here's the |squash| procedure, which combines |big_app|${}_k$ and
|reduce| for matching numbers~|k|.

@c
static void
squash(
scrap_pointer j, short k,
eight_bits c,
short d, short n)
{
  switch (k) {
  case 1: big_app1(j); break;
  case 2: big_app2(j); break;
  case 3: big_app3(j); break;
  case 4: big_app4(j); break;
  default: confusion("squash");
  }
  reduce(j,k,c,d,n);
}

@ And here now is the code that applies productions as long as possible.
Before applying the production mechanism, we must make sure
it has good input (at least four scraps, the length of the lhs of the
longest rules), and that there is enough room in the memory arrays
to hold the appended tokens and texts.  Here we use a very
conservative test; it's more important to make sure the program
will still work if we change the production rules (within reason)
than to squeeze the last bit of space from the memory arrays.

@d safe_tok_incr 20
@d safe_text_incr 10
@d safe_scrap_incr 10

@<Reduce the scraps using the productions until no more rules apply@>=
while (true) {
  @<Make sure the entries |pp| through |pp+3| of |cat| are defined@>@;
  if (tok_ptr+safe_tok_incr>tok_mem_end) {
    if (tok_ptr>max_tok_ptr) max_tok_ptr=tok_ptr;
    overflow("token");
  }
  if (text_ptr+safe_text_incr>tok_start_end) {
    if (text_ptr>max_text_ptr) max_text_ptr=text_ptr;
    overflow("text");
  }
  if (pp>lo_ptr) break;
  init_mathness=cur_mathness=maybe_math;
  @<Match a production...@>@;
}

@ If we get to the end of the scrap list, category codes equal to zero are
stored, since zero does not match anything in a production.

@<Make sure the entries...@>=
if (lo_ptr<pp+3) {
  while (hi_ptr<=scrap_ptr && lo_ptr!=pp+3) {
    (++lo_ptr)->cat=hi_ptr->cat; lo_ptr->mathness=hi_ptr->mathness;
    lo_ptr->trans=(hi_ptr++)->trans;
  }
  for (i=lo_ptr+1;i<=pp+3;i++) i->cat=0;
}

@ If \.{CWEAVE} is being run in debugging mode, the production numbers and
current stack categories will be printed out when |tracing| is set to |fully|;
a sequence of two or more irreducible scraps will be printed out when
|tracing| is set to |partly|.

@d off 0
@d partly 1
@d fully 2

@<Private...@>=
static int tracing=off; /* can be used to show parsing details */

@ @<Print a snapsh...@>=
if (tracing==fully) {
  scrap_pointer k; /* pointer into |scrap_info|; shadows |short k| */
  printf("\n%d:",n);
  for (k=scrap_base; k<=lo_ptr; k++) {
    if (k==pp) putchar('*'); else putchar(' ');
    if (k->mathness %4 == yes_math) putchar('+');
    else if (k->mathness %4 == no_math) putchar('-');
    print_cat(k->cat);
    if (k->mathness /4 == yes_math) putchar('+');
    else if (k->mathness /4 == no_math) putchar('-');
  }
  if (hi_ptr<=scrap_ptr) printf("..."); /* indicate that more is coming */
}

@ The |translate| function assumes that scraps have been stored in
positions |scrap_base| through |scrap_ptr| of |cat| and |trans|. It
applies productions as much as
possible. The result is a token list containing the translation of
the given sequence of scraps.

After calling |translate|, we will have |text_ptr+3<=max_texts| and
|tok_ptr+6<=max_toks|, so it will be possible to create up to three token
lists with up to six tokens without checking for overflow. Before calling
|translate|, we should have |text_ptr<max_texts| and |scrap_ptr<max_scraps|,
since |translate| might add a new text and a new scrap before it checks
for overflow.

@c
static text_pointer
translate(void) /* converts a sequence of scraps */
{
  scrap_pointer i; /* index into |cat| */
  scrap_pointer j; /* runs through final scraps */
  pp=scrap_base; lo_ptr=pp-1; hi_ptr=pp;
  @<If tracing, print an indication of where we are@>@;
  @<Reduce the scraps...@>@;
  @<Combine the irreducible scraps that remain@>@;
}

@ @<Predecl...@>=@+static text_pointer translate(void);

@ If the initial sequence of scraps does not reduce to a single scrap,
we concatenate the translations of all remaining scraps, separated by
blank spaces, with dollar signs surrounding the translations of scraps
where appropriate.

@<Combine the irreducible...@>=
@<If semi-tracing, show the irreducible scraps@>@;
for (j=scrap_base; j<=lo_ptr; j++) {
  if (j!=scrap_base) app(' ');
  if (j->mathness % 4 == yes_math) app('$');
  app(tok_flag+(int)(j->trans-tok_start));
  if (j->mathness / 4 == yes_math) app('$');
  if (tok_ptr+6>tok_mem_end) overflow("token");
}
freeze_text; return text_ptr-1;

@ @<If semi-tracing, show the irreducible scraps@>=
if (lo_ptr>scrap_base && tracing==partly) {
  printf("\nIrreducible scrap sequence in section %d:",(int)section_count);
@.Irreducible scrap sequence...@>
  mark_harmless;
  for (j=scrap_base; j<=lo_ptr; j++) {
    putchar(' '); print_cat(j->cat);
  }
}

@ @<If tracing,...@>=
if (tracing==fully) {
  printf("\nTracing after l. %d:\n",cur_line); mark_harmless;
@.Tracing after...@>
  if (loc>buffer+50) {
    printf("...");
    term_write(loc-51,51);
  }
  else term_write(buffer,loc-buffer);
}

@* Initializing the scraps.
If we are going to use the powerful production mechanism just developed, we
must get the scraps set up in the first place, given a \CEE/ text. A table
of the initial scraps corresponding to \CEE/ tokens appeared above in the
section on parsing; our goal now is to implement that table. We shall do this
by implementing a subroutine called |C_parse| that is analogous to the
|C_xref| routine used during phase one.

Like |C_xref|, the |C_parse| procedure starts with the current
value of |next_control| and it uses the operation |next_control=get_next()|
repeatedly to read \CEE/ text until encountering the next `\.{\v}' or
`\.{/*}', or until |next_control>=format_code|. The scraps corresponding to
what it reads are appended into the |cat| and |trans| arrays, and |scrap_ptr|
is advanced.

@c
static void
C_parse( /* creates scraps from \CEE/ tokens */
  eight_bits spec_ctrl)
{
  while (next_control<format_code || next_control==spec_ctrl) {
    @<Append the scrap appropriate to |next_control|@>@;
    next_control=get_next();
    if (next_control=='|' || next_control==begin_comment ||
        next_control==begin_short_comment) return;
  }
}

@ @<Predecl...@>=@+static void C_parse(eight_bits);

@ The following macro is used to append a scrap whose tokens have just
been appended:

@d app_scrap(c,b) {
  (++scrap_ptr)->cat=(c); scrap_ptr->trans=text_ptr;
  scrap_ptr->mathness=5*(b); /* no no, yes yes, or maybe maybe */
  freeze_text;
}

@ @<Append the scr...@>=
@<Make sure that there is room for the new scraps, tokens, and texts@>@;
switch (next_control) {
  case section_name:
    app(section_flag+(int)(cur_section-name_dir));
    app_scrap(section_scrap,maybe_math);@+
    app_scrap(exp,yes_math);@+break;
  case string: case constant: case verbatim:
    @<Append a string or constant@>@;@+break;
  case identifier: app_cur_id(true);@+break;
  case TeX_string:
    @<Append a \TEX/ string, without forming a scrap@>@;@+break;
  case '/': case '.':
    app(next_control);@+app_scrap(binop,yes_math);@+break;
  case '<': app_str("\\langle");@+app_scrap(prelangle,yes_math);@+break;
@.\\langle@>
  case '>': app_str("\\rangle");@+app_scrap(prerangle,yes_math);@+break;
@.\\rangle@>
  case '=': app_str("\\K");@+app_scrap(binop,yes_math);@+break;
@.\\K@>
  case '|': app_str("\\OR");@+app_scrap(binop,yes_math);@+break;
@.\\OR@>
  case '^': app_str("\\XOR");@+app_scrap(binop,yes_math);@+break;
@.\\XOR@>
  case '%': app_str("\\MOD");@+app_scrap(binop,yes_math);@+break;
@.\\MOD@>
  case '!': app_str("\\R");@+app_scrap(unop,yes_math);@+break;
@.\\R@>
  case '~': app_str("\\CM");@+app_scrap(unop,yes_math);@+break;
@.\\CM@>
  case '+': case '-': app(next_control);@+app_scrap(ubinop,yes_math);@+break;
  case '*': app(next_control);@+app_scrap(raw_ubin,yes_math);@+break;
  case '&': app_str("\\AND");@+app_scrap(raw_ubin,yes_math);@+break;
@.\\AND@>
  case '?': app_str("\\?");@+app_scrap(question,yes_math);@+break;
@.\\?@>
  case '#': app_str("\\#");@+app_scrap(ubinop,yes_math);@+break;
@.\\\#@>
  case ignore: case xref_roman: case xref_wildcard:
  case xref_typewriter: case noop:@+break;
  case '(': app(next_control);@+app_scrap(lpar,maybe_math);@+break;
  case ')': app(next_control);@+app_scrap(rpar,maybe_math);@+break;
  case '[': app(next_control);@+app_scrap(lbrack,maybe_math);@+break;
  case ']': app(next_control);@+app_scrap(rbrack,maybe_math);@+break;
  case '{': app_str("\\{"@q}@>);@+app_scrap(lbrace,yes_math);@+break;
@.\\\{@>@q}@>
  case '}': app_str(@q{@>"\\}");@+app_scrap(rbrace,yes_math);@+break;
@q{@>@.\\\}@>
  case ',': app(',');@+app_scrap(comma,yes_math);@+break;
  case ';': app(';');@+app_scrap(semi,maybe_math);@+break;
  case ':': app(':');@+app_scrap(colon,no_math);@+break;@/
  @t\4@> @<Cases involving nonstandard characters@>@;
  case thin_space: app_str("\\,");@+app_scrap(insert,maybe_math);@+break;
@.\\,@>
  case math_break: app(opt);@+app('0');@+
    app_scrap(insert,maybe_math);@+break;
  case line_break: app(force);@+app_scrap(insert,no_math);@+break;
  case left_preproc: app(force);@+app(preproc_line);@+app_str("\\#");
    app_scrap(lproc,no_math);@+break;
@.\\\#@>
  case right_preproc: app(force);@+app_scrap(rproc,no_math);@+break;
  case big_line_break: app(big_force);@+app_scrap(insert,no_math);@+break;
  case no_line_break: app(big_cancel);@+app(noop);@+app(break_space);@+
    app(noop);@+app(big_cancel);
    app_scrap(insert,no_math);@+break;
  case pseudo_semi: app_scrap(semi,maybe_math);@+break;
  case macro_arg_open: app_scrap(begin_arg,maybe_math);@+break;
  case macro_arg_close: app_scrap(end_arg,maybe_math);@+break;
  case join: app_str("\\J");@+app_scrap(insert,no_math);@+break;
@.\\J@>
  case output_defs_code: app(force);@+app_str("\\ATH");@+app(force);
    app_scrap(insert,no_math);@+break;
@.\\ATH@>
  default: app(inserted);@+app(next_control);
    app_scrap(insert,maybe_math);@+break;
}

@ @<Make sure that there is room for the new...@>=
if (scrap_ptr+safe_scrap_incr>scrap_info_end ||
  tok_ptr+safe_tok_incr>tok_mem_end @| ||
  text_ptr+safe_text_incr>tok_start_end) {
  if (scrap_ptr>max_scr_ptr) max_scr_ptr=scrap_ptr;
  if (tok_ptr>max_tok_ptr) max_tok_ptr=tok_ptr;
  if (text_ptr>max_text_ptr) max_text_ptr=text_ptr;
  overflow("scrap/token/text");
}

@ Some nonstandard characters may have entered \.{CWEAVE} by means of
standard ones. They are converted to \TEX/ control sequences so that it is
possible to keep \.{CWEAVE} from outputting unusual |char| codes.

@<Cases involving nonstandard...@>=@t\1\quad@>
case non_eq: app_str("\\I");@+app_scrap(binop,yes_math);@+break;
@.\\I@>
case lt_eq: app_str("\\Z");@+app_scrap(binop,yes_math);@+break;
@.\\Z@>
case gt_eq: app_str("\\G");@+app_scrap(binop,yes_math);@+break;
@.\\G@>
case eq_eq: app_str("\\E");@+app_scrap(binop,yes_math);@+break;
@.\\E@>
case and_and: app_str("\\W");@+app_scrap(binop,yes_math);@+break;
@.\\W@>
case or_or: app_str("\\V");@+app_scrap(binop,yes_math);@+break;
@.\\V@>
case plus_plus: app_str("\\PP");@+app_scrap(unop,yes_math);@+break;
@.\\PP@>
case minus_minus: app_str("\\MM");@+app_scrap(unop,yes_math);@+break;
@.\\MM@>
case minus_gt: app_str("\\MG");@+app_scrap(binop,yes_math);@+break;
@.\\MG@>
case gt_gt: app_str("\\GG");@+app_scrap(binop,yes_math);@+break;
@.\\GG@>
case lt_lt: app_str("\\LL");@+app_scrap(binop,yes_math);@+break;
@.\\LL@>
case dot_dot_dot: app_str("\\,\\ldots\\,");@+app_scrap(raw_int,yes_math);
  @+break;
@.\\,@>
@.\\ldots@>
case colon_colon: app_str("\\DC");@+app_scrap(colcol,maybe_math);@+break;
@.\\DC@>
case period_ast: app_str("\\PA");@+app_scrap(binop,yes_math);@+break;
@.\\PA@>
case minus_gt_ast: app_str("\\MGA");@+app_scrap(binop,yes_math);@+break;
@.\\MGA@>

@ The following code must use |app_tok| instead of |app| in order to
protect against overflow. Note that |tok_ptr+1<=max_toks| after |app_tok|
has been used, so another |app| is legitimate before testing again.

Many of the special characters in a string must be prefixed by `\.\\' so that
\TEX/ will print them properly.
@^special string characters@>

@<Append a string or...@>={@+ int count=-1; /* characters remaining before string break */
switch (next_control) {
  case constant: app_str("\\T{"@q}@>); break;
@.\\T@>
  case string: count=20; app_str("\\.{"@q}@>); break;
@.\\.@>
  default: app_str("\\vb{"@q}@>);
@.\\vb@>
}
while (id_first<id_loc) {
  if (count==0) { /* insert a discretionary break in a long string */
     app_str(@q(@>@q{@>"}\\)\\.{"@q}@>); count=20;
@q(@>@.\\)@>
  }
  switch (*id_first) {
    case ' ':case '\\':case '#':case '%':case '$':case '^':
    case '{': case '}': case '~': case '&': case '_': app('\\'); break;
@.\\\ @>
@.\\\\@>
@.\\\#@>
@.\\\%@>
@.\\\$@>
@.\\\^@>
@.\\\{@>@q}@>
@q{@>@.\\\}@>
@.\\\~@>
@.\\\&@>
@.\\\_@>
    case '@@': if (*(id_first+1)=='@@') id_first++;
      else err_print("! Double @@ should be used in strings");
@.Double @@ should be used...@>
      break;
    default: /* high-bit character handling */
@^high-bit character handling@>
      if((eight_bits)(*id_first)>0177)
        app_tok(quoted_char)@t;@>@;
    }
  app_tok(*id_first++);
  count--;
}
app(@q{@>'}');
app_scrap(exp,maybe_math);
}

@ We do not make the \TEX/ string into a scrap, because there is no
telling what the user will be putting into it; instead we leave it
open, to be picked up by the next scrap. If it comes at the end of a
section, it will be made into a scrap when |finish_C| is called.

There's a known bug here, in cases where an adjacent scrap is
|prelangle| or |prerangle|. Then the \TEX/ string can disappear
when the \.{\\langle} or \.{\\rangle} becomes \.{<} or \.{>}.
For example, if the user writes \.{\v x<@@ty@@>\v}, the \TEX/ string
\.{\\hbox\{y\}} eventually becomes part of an |insert| scrap, which is combined
with a |prelangle| scrap and eventually lost. The best way to work around
this bug is probably to enclose the \.{@@t...@@>} in \.{@@[...@@]} so that
the \TEX/ string is treated as an expression.
@^bug, known@>

@<Append a \TEX/ string, without forming a scrap@>=
app_str("\\hbox{"@q}@>);
@^high-bit character handling@>
while (id_first<id_loc) {
  if((eight_bits)(*id_first)>0177)
    app_tok(quoted_char)@t;@>@;
  else
    if (*id_first=='@@') id_first++;
  app_tok(*id_first++);
}
app(@q{@>'}');

@ The function |app_cur_id| appends the current identifier to the
token list; it also builds a new scrap if |scrapping==true|.

@<Predec...@>=
static void app_cur_id(boolean);@/
static text_pointer C_translate(void);@/
static void outer_parse(void);

@ @c
static void
app_cur_id(
boolean scrapping) /* are we making this into a scrap? */
{
  name_pointer p=id_lookup(id_first,id_loc,normal);
  if (p->ilk<=custom) { /* not a reserved word */
    app(id_flag+(int)(p-name_dir));
    if (scrapping) app_scrap(p->ilk==func_template? ftemplate: exp,
                             p->ilk==custom? yes_math: maybe_math);
@.\\NULL@>
  } else {
    app(res_flag+(int)(p-name_dir));
    if (scrapping) {
      if (p->ilk==alfop) app_scrap(ubinop,yes_math)@t;@>@;
      else app_scrap(p->ilk,maybe_math);
    }
  }
}

@ When the `\.{\v}' that introduces \CEE/ text is sensed, a call on
|C_translate| will return a pointer to the \TEX/ translation of
that text. If scraps exist in |scrap_info|, they are
unaffected by this translation process.

@c
static text_pointer
C_translate(void)
{
  text_pointer p; /* points to the translation */
  scrap_pointer save_base=scrap_base; /* holds original value of |scrap_base| */
  scrap_base=scrap_ptr+1;
  C_parse(section_name); /* get the scraps together */
  if (next_control!='|') err_print("! Missing '|' after C text");
@.Missing '|'...@>
  app_tok(cancel); app_scrap(insert,maybe_math);
        /* place a |cancel| token as a final ``comment'' */
  p=translate(); /* make the translation */
  if (scrap_ptr>max_scr_ptr) max_scr_ptr=scrap_ptr;
  scrap_ptr=scrap_base-1; scrap_base=save_base; /* scrap the scraps */
  return p;
}

@ The |outer_parse| routine is to |C_parse| as |outer_xref|
is to |C_xref|: It constructs a sequence of scraps for \CEE/ text
until |next_control>=format_code|. Thus, it takes care of embedded comments.

The token list created from within `\pb' brackets is output as an argument
to \.{\\PB}.  Although \.{cwebmac} ignores \.{\\PB}, other macro packages
might use it to localize the special meaning of the macros that mark up
program text.

@d make_pb flags['e']

@<Set init...@>=
make_pb=true;

@ @c
static void
outer_parse(void) /* makes scraps from \CEE/ tokens and comments */
{
  int bal; /* brace level in comment */
  text_pointer p, q; /* partial comments */
  while (next_control<format_code)
    if (next_control!=begin_comment && next_control!=begin_short_comment)
      C_parse(ignore);
    else {
      boolean is_long_comment=(next_control==begin_comment);
      @<Make sure that there is room for the new...@>@;
      app(cancel); app(inserted);
      if (is_long_comment) app_str("\\C{"@q}@>);
@.\\C@>
      else app_str("\\SHC{"@q}@>);
@.\\SHC@>
      bal=copy_comment(is_long_comment,1); next_control=ignore;
      while (bal>0) {
        p=text_ptr; freeze_text; q=C_translate();
         /* at this point we have |tok_ptr+6<=max_toks| */
        app(tok_flag+(int)(p-tok_start));
        if (make_pb) app_str("\\PB{");
@.\\PB@>
        app(inner_tok_flag+(int)(q-tok_start));
        if (make_pb) app_tok('}');
        if (next_control=='|') {
          bal=copy_comment(is_long_comment,bal);
          next_control=ignore;
        }
        else bal=0; /* an error has been reported */
      }
      app(force); app_scrap(insert,no_math);
        /* the full comment becomes a scrap */
    }
}

@* Output of tokens.
So far our programs have only built up multi-layered token lists in
\.{CWEAVE}'s internal memory; we have to figure out how to get them into
the desired final form. The job of converting token lists to characters in
the \TEX/ output file is not difficult, although it is an implicitly
recursive process. Four main considerations had to be kept in mind when
this part of \.{CWEAVE} was designed. (a) There are two modes of output:
|outer| mode, which translates tokens like |force| into line-breaking
control sequences, and |inner| mode, which ignores them except that blank
spaces take the place of line breaks. (b) The |cancel| instruction applies
to adjacent token or tokens that are output, and this cuts across levels
of recursion since `|cancel|' occurs at the beginning or end of a token
list on one level. (c) The \TEX/ output file will be semi-readable if line
breaks are inserted after the result of tokens like |break_space| and
|force|. (d) The final line break should be suppressed, and there should
be no |force| token output immediately after `\.{\\Y\\B}'.

@ The output process uses a stack to keep track of what is going on at
different ``levels'' as the token lists are being written out. Entries on
this stack have three parts:

\yskip\hang |end_field| is the |tok_mem| location where the token list of a
particular level will end;

\yskip\hang |tok_field| is the |tok_mem| location from which the next token
on a particular level will be read;

\yskip\hang |mode_field| is the current mode, either |inner| or |outer|.

\yskip\noindent The current values of these quantities are referred to
quite frequently, so they are stored in a separate place instead of in the
|stack| array. We call the current values |cur_end|, |cur_tok|, and
|cur_mode|.

The global variable |stack_ptr| tells how many levels of output are
currently in progress. The end of output occurs when an |end_translation|
token is found, so the stack is never empty except when we first begin the
output process.

@d inner false /* value of |mode| for \CEE/ texts within \TEX/ texts */
@d outer true /* value of |mode| for \CEE/ texts in sections */

@<Typed...@>= typedef int mode;
typedef struct {
  token_pointer end_field; /* ending location of token list */
  token_pointer tok_field; /* present location within token list */
  boolean mode_field; /* interpretation of control tokens */
} output_state;
typedef output_state *stack_pointer;

@ @d stack_size 400 /* number of simultaneous output levels */
@d cur_end cur_state.end_field /* current ending location in |tok_mem| */
@d cur_tok cur_state.tok_field /* location of next output token in |tok_mem| */
@d cur_mode cur_state.mode_field /* current mode of interpretation */
@d init_stack stack_ptr=stack;cur_mode=outer /* initialize the stack */

@<Private...@>=
static output_state cur_state; /* |cur_end|, |cur_tok|, |cur_mode| */
static output_state stack[stack_size]; /* info for non-current levels */
static stack_pointer stack_end=stack+stack_size-1; /* end of |stack| */
static stack_pointer stack_ptr; /* first unused location in the output state stack */
static stack_pointer max_stack_ptr; /* largest value assumed by |stack_ptr| */

@ @<Set init...@>=
max_stack_ptr=stack;

@ To insert token-list |p| into the output, the |push_level| subroutine
is called; it saves the old level of output and gets a new one going.
The value of |cur_mode| is not changed.

@<Predecl...@>=
static void push_level(text_pointer);@/
static void pop_level(void);

@ @c
static void
push_level( /* suspends the current level */
text_pointer p)
{
  if (stack_ptr==stack_end) overflow("stack");
  if (stack_ptr>stack) { /* save current state */
    stack_ptr->end_field=cur_end;
    stack_ptr->tok_field=cur_tok;
    stack_ptr->mode_field=cur_mode;
  }
  stack_ptr++;
  if (stack_ptr>max_stack_ptr) max_stack_ptr=stack_ptr;
  cur_tok=*p; cur_end=*(p+1);
}

@ Conversely, the |pop_level| routine restores the conditions that were in
force when the current level was begun. This subroutine will never be
called when |stack_ptr==1|.

@c
static void
pop_level(void)
{
  cur_end=(--stack_ptr)->end_field;
  cur_tok=stack_ptr->tok_field; cur_mode=stack_ptr->mode_field;
}

@ The |get_output| function returns the next byte of output that is not a
reference to a token list. It returns the values |identifier| or |res_word|
or |section_code| if the next token is to be an identifier (typeset in
italics), a reserved word (typeset in boldface), or a section name (typeset
by a complex routine that might generate additional levels of output).
In these cases |cur_name| points to the identifier or section name in
question.

@<Private...@>=
static name_pointer cur_name;

@ @d res_word 0201 /* returned by |get_output| for reserved words */
@d section_code 0200 /* returned by |get_output| for section names */

@<Predecl...@>=
static eight_bits get_output(void);@/
static void output_C(void);@/
static void make_output(void);

@ @c
static eight_bits
get_output(void) /* returns the next token of output */
{
  sixteen_bits a; /* current item read from |tok_mem| */
  restart: while (cur_tok==cur_end) pop_level();
  a=*(cur_tok++);
  if (a>=0400) {
    cur_name=a % id_flag + name_dir;
    switch (a / id_flag) {
      case 2: return res_word ; /* |a==res_flag+cur_name| */
      case 3: return section_code ; /* |a==section_flag+cur_name| */
      case 4: push_level(a % id_flag + tok_start); goto restart;
        /* |a==tok_flag+cur_name| */
      case 5: push_level(a % id_flag + tok_start); cur_mode=inner; goto restart;
        /* |a==inner_tok_flag+cur_name| */
      default: return identifier; /* |a==id_flag+cur_name| */
    }
  }
  return (eight_bits)a;
}

@ The real work associated with token output is done by |make_output|.
This procedure appends an |end_translation| token to the current token list,
and then it repeatedly calls |get_output| and feeds characters to the output
buffer until reaching the |end_translation| sentinel. It is possible for
|make_output| to be called recursively, since a section name may include
embedded \CEE/ text; however, the depth of recursion never exceeds one
level, since section names cannot be inside of section names.

A procedure called |output_C| does the scanning, translation, and
output of \CEE/ text within `\pb' brackets, and this procedure uses
|make_output| to output the current token list. Thus, the recursive call
of |make_output| actually occurs when |make_output| calls |output_C|
while outputting the name of a section.
@^recursion@>

@c
static void
output_C(void) /* outputs the current token list */
{
  token_pointer save_tok_ptr=tok_ptr;
  text_pointer save_text_ptr=text_ptr;
  sixteen_bits save_next_control=next_control; /* values to be restored */
  text_pointer p; /* translation of the \CEE/ text */
  next_control=ignore; p=C_translate();
  app(inner_tok_flag+(int)(p-tok_start));
  if (make_pb) {
    out_str("\\PB{"); make_output(); out('}');
@.\\PB@>
  }@+else make_output(); /* output the list */
  if (text_ptr>max_text_ptr) max_text_ptr=text_ptr;
  if (tok_ptr>max_tok_ptr) max_tok_ptr=tok_ptr;
  text_ptr=save_text_ptr; tok_ptr=save_tok_ptr; /* forget the tokens */
  next_control=save_next_control; /* restore |next_control| to original state */
}

@ Here is \.{CWEAVE}'s major output handler.

@c
static void
make_output(void) /* outputs the equivalents of tokens */
{
  eight_bits a=0; /* current output byte */
  eight_bits b; /* next output byte */
  int c; /* count of |indent| and |outdent| tokens */
  char scratch[longest_name+1]; /* scratch area for section names */
  char *k, *k_limit; /* indices into |scratch| */
  char *j; /* index into |buffer| */
  char *p; /* index into |byte_mem| */
  char delim; /* first and last character of string being copied */
  char *save_loc, *save_limit; /* |loc| and |limit| to be restored */
  name_pointer cur_section_name; /* name of section being output */
  boolean save_mode; /* value of |cur_mode| before a sequence of breaks */
  boolean dindent_pending=false; /* should a |dindent| be output? */
  app(end_translation); /* append a sentinel */
  freeze_text; push_level(text_ptr-1);
  while (true) {
    a=get_output();
    reswitch: switch(a) {
      case end_translation: return;
      case identifier: case res_word: @<Output an identifier@>@; break;
      case section_code: @<Output a section name@>@; break;
      case math_rel: out_str("\\MRL{"@q}@>); /* fall through */
@.\\MRL@>
      case noop: case inserted: break;
      case cancel: case big_cancel: c=0; b=a;
        while (true) {
          a=get_output();
          if (a==inserted) continue;
          if ((a<indent && !(b==big_cancel&&a==' ')) @|
            || (a>big_force && a!=dindent)) break;
          switch (a) {
          case indent: c++; break;
          case outdent: c--; break;
          case dindent: c+=2; break;
          case opt: a=get_output();
          }
        }
        @<Output saved |indent| or |outdent| tokens@>@;
        goto reswitch;
      case dindent: a=get_output();
        if (a!=big_force) {
          out_str("\\1\\1"); goto reswitch;
        }
        else dindent_pending=true; /* fall through */
      case indent: case outdent: case opt: case backup: case break_space:
      case force: case big_force: case preproc_line: @<Output a control,
        look ahead in case of line breaks, possibly |goto reswitch|@>@; break;
      case quoted_char: out(*(cur_tok++)); /* fall through */
      case qualifier: break;
      default: out(a); /* otherwise |a| is an ordinary character */
    }
  }
}

@ An identifier of length one does not have to be enclosed in braces, and it
looks slightly better if set in a math-italic font instead of a (slightly
narrower) text-italic font. Thus we output `\.{\\\v}\.{a}' but
`\.{\\\\\{aa\}}'.

@<Output an identifier@>=
out('\\');
if (a==identifier) {
  if (cur_name->ilk==custom && !doing_format) {
 custom_out:
    for (p=cur_name->byte_start;p<(cur_name+1)->byte_start;p++)
      out(*p=='_'? 'x': *p=='$'? 'X': *p);
    break;
  }
  else if (is_tiny(cur_name)) out('|')@t;@>@;
@.\\|@>
  else { delim='.';
    for (p=cur_name->byte_start;p<(cur_name+1)->byte_start;p++)
      if (xislower(*p)) { /* not entirely uppercase */
         delim='\\'; break;
      }
  out(delim);
  }
@.\\\\@>
@.\\.@>
}
else if (cur_name->ilk==alfop) {
  out('X');
  goto custom_out;
}
else out('&'); /* |a==res_word| */
@.\\\&@>
if (is_tiny(cur_name)) {
  if (isxalpha((cur_name->byte_start)[0]))
    out('\\');
  out((cur_name->byte_start)[0]);
}
else out_name(cur_name,true);

@ The current mode does not affect the behavior of \.{CWEAVE}'s output routine
except when we are outputting control tokens.

@<Output a control...@>=
if (a<break_space || a==preproc_line) {
  if (cur_mode==outer) {
    out('\\'); out(a-cancel+'0');
@.\\1@>
@.\\2@>
@.\\3@>
@.\\4@>
@.\\8@>
    if (a==opt) {
      b=get_output(); /* |opt| is followed by a digit */
      if (b!='0' || force_lines==false) out(b)@t;@>@;
      else out_str("{-1}"); /* |force_lines| encourages more \.{@@\v} breaks */
    }
  } else if (a==opt) b=get_output(); /* ignore digit following |opt| */
}
else @<Look ahead for strongest line break, |goto reswitch|@>

@ If several of the tokens |break_space|, |force|, |big_force| occur in a
row, possibly mixed with blank spaces (which are ignored),
the largest one is used. A line break also occurs in the output file,
except at the very end of the translation. The very first line break
is suppressed (i.e., a line break that follows `\.{\\Y\\B}').

@<Look ahead for st...@>= {
  b=a; save_mode=cur_mode;
  if (dindent_pending) {
    c=2; dindent_pending=false;
  } else c=0;
  while (true) {
    a=get_output();
    if (a==inserted) continue;
    if (a==cancel || a==big_cancel) {
      @<Output saved |indent| or |outdent| tokens@>@;
      goto reswitch; /* |cancel| overrides everything */
    }
    if ((a!=' ' && a<indent) || a==backup || a>big_force) {
      if (save_mode==outer) {
        if (out_ptr>out_buf+3 && strncmp(out_ptr-3,"\\Y\\B",4)==0)
          goto reswitch;
        @<Output saved |indent| or |outdent| tokens@>@;
        out('\\'); out(b-cancel+'0');
@.\\5@>
@.\\6@>
@.\\7@>
        if (a!=end_translation) finish_line();
      }
      else if (a!=end_translation && cur_mode==inner) out(' ');
      goto reswitch;
    }
    if (a==indent) c++;
    else if (a==outdent) c--;
    else if (a==opt) a=get_output();
    else if (a>b) b=a; /* if |a==' '| we have |a<b| */
  }
}

@ @<Output saved...@>=
  for (;c>0;c--) out_str("\\1");
@.\\1@>
  for (;c<0;c++) out_str("\\2");
@.\\2@>

@ The remaining part of |make_output| is somewhat more complicated. When we
output a section name, we may need to enter the parsing and translation
routines, since the name may contain \CEE/ code embedded in
\pb\ constructions. This \CEE/ code is placed at the end of the active
input buffer and the translation process uses the end of the active
|tok_mem| area.

@<Output a section name@>=
out_str("\\X");
@.\\X@>
cur_xref=(xref_pointer)cur_name->xref;
if ((an_output=(cur_xref->num==file_flag))==true) cur_xref=cur_xref->xlink;
if (cur_xref->num>=def_flag) {
  out_section(cur_xref->num-def_flag);
  if (phase==3) {
    cur_xref=cur_xref->xlink;
    while (cur_xref->num>=def_flag) {
      out_str(", ");
      out_section(cur_xref->num-def_flag);
    cur_xref=cur_xref->xlink;
    }
  }
}
else out('0'); /* output the section number, or zero if it was undefined */
out(':');
if (an_output) out_str("\\.{"@q}@>);
@.\\.@>
@<Output the text of the section name@>@;
if (an_output) out_str(@q{@>" }");
out_str("\\X");

@ @<Output the text...@>=
sprint_section_name(scratch,cur_name);
k=scratch;
k_limit=scratch+strlen(scratch);
cur_section_name=cur_name;
while (k<k_limit) {
  b=*(k++);
  if (b=='@@') @<Skip next character, give error if not `\.{@@}'@>@;
  if (an_output)
    switch (b) {
    case ' ': case '\\': case '#': case '%': case '$': case '^':
    case '{': case '}': case '~': case '&': case '_':
      out('\\'); /* falls through */
@.\\\ @>
@.\\\\@>
@.\\\#@>
@.\\\%@>
@.\\\$@>
@.\\\^@>
@.\\\{@>@q}@>
@q{@>@.\\\}@>
@.\\\~@>
@.\\\&@>
@.\\\_@>
    default: out(b);
    }
  else
    if (b!='|') out(b)@t;@>@;
    else {
      @<Copy the \CEE/ text into the |buffer| array@>@;
      save_loc=loc; save_limit=limit; loc=limit+2; limit=j+1;
      *limit='|'; output_C();
      loc=save_loc; limit=save_limit;
    }
}

@ @<Skip next char...@>=
if (*k++!='@@') {
  fputs("\n! Illegal control code in section name: <",stdout);
@.Illegal control code...@>
  print_section_name(cur_section_name); printf("> "); mark_error;
}

@ The \CEE/ text enclosed in \pb\ should not contain `\.{\v}' characters,
except within strings. We put a `\.{\v}' at the front of the buffer, so that an
error message that displays the whole buffer will look a little bit sensible.
The variable |delim| is zero outside of strings, otherwise it
equals the delimiter that began the string being copied.

@<Copy the \CEE/ text into...@>=
j=limit+1; *j='|'; delim=0;
while (true) {
  if (k>=k_limit) {
    fputs("\n! C text in section name didn't end: <",stdout);
@.C text...didn't end@>
    print_section_name(cur_section_name); printf("> "); mark_error; break;
  }
  b=*(k++);
  if (b=='@@' || (b=='\\' && delim!=0))
     @<Copy a quoted character into the buffer@>@;
  else {
    if (b=='\'' || b=='"') {
      if (delim==0) delim=b;
      else if (delim==b) delim=0; }
    if (b!='|' || delim!=0) {
      if (j>buffer+long_buf_size-3) overflow("buffer");
      *(++j)=b;
    }
    else break;
  }
}

@ @<Copy a quoted char...@>= {
  if (j>buffer+long_buf_size-4) overflow("buffer");
  *(++j)=b; *(++j)=*(k++);
}

@** Phase two processing.
We have assembled enough pieces of the puzzle in order to be ready to specify
the processing in \.{CWEAVE}'s main pass over the source file. Phase two
is analogous to phase one, except that more work is involved because we must
actually output the \TEX/ material instead of merely looking at the
\.{CWEB} specifications.

@c
static void
phase_two(void) {
phase=2; reset_input();
if (show_progress) fputs("\nWriting the output file...",stdout);
@.Writing the output file...@>
section_count=0; format_visible=true; copy_limbo();
finish_line(); flush_buffer(out_buf,false,false);
  /* insert a blank line, it looks nice */
while (!input_has_ended) @<Translate the current section@>@;
}

@ @<Predecl...@>=@+static void phase_two(void);

@ The output file will contain the control sequence \.{\\Y} between non-null
sections of a section, e.g., between the \TEX/ and definition parts if both
are nonempty. This puts a little white space between the parts when they are
printed. However, we don't want \.{\\Y} to occur between two definitions
within a single section. The variables |out_line| or |out_ptr| will
change if a section is non-null, so the following macros `|save_position|'
and `|emit_space_if_needed|' are able to handle the situation:

@d save_position save_line=out_line; save_place=out_ptr
@d emit_space_if_needed if (save_line!=out_line || save_place!=out_ptr)
  out_str("\\Y");
  space_checked=true;
@.\\Y@>

@<Private...@>=
static int save_line; /* former value of |out_line| */
static char *save_place; /* former value of |out_ptr| */
static int sec_depth; /* the integer, if any, following \.{@@*} */
static boolean space_checked; /* have we done |emit_space_if_needed|? */
static boolean format_visible; /* should the next format declaration be output? */
static boolean doing_format=false; /* are we outputting a format declaration? */
static boolean group_found=false; /* has a starred section occurred? */

@ @<Translate the current section@>= {
  section_count++;
  @<Output the code for the beginning of a new section@>@;
  save_position;
  @<Translate the \TEX/ part of the current section@>@;
  @<Translate the definition part of the current section@>@;
  @<Translate the \CEE/ part of the current section@>@;
  @<Show cross-references to this section@>@;
  @<Output the code for the end of a section@>@;
}

@ Sections beginning with the \.{CWEB} control sequence `\.{@@\ }' start in the
output with the \TEX/ control sequence `\.{\\M}', followed by the section
number. Similarly, `\.{@@*}' sections lead to the control sequence `\.{\\N}'.
In this case there's an additional parameter, representing one plus the
specified depth, immediately after the~\.{\\N}.
If the section has changed, we put \.{\\*} just after the section number.

@<Output the code for the beginning...@>=
if (*(loc-1)!='*') out_str("\\M");
@.\\M@>
else {
  while (*loc == ' ') loc++;
  if (*loc=='*') { /* ``top'' level */
    sec_depth = -1;
    loc++;
  }
  else {
    for (sec_depth=0; xisdigit(*loc);loc++)
      sec_depth = sec_depth*10 + (*loc) -'0';
  }
  while (*loc == ' ') loc++; /* remove spaces before group title */
  group_found=true;
  out_str("\\N");
@.\\N@>
  {@+ char s[32];@+sprintf(s,"{%d}",sec_depth+1);@+out_str(s);@+}
  if (show_progress)
  printf("*%d",(int)section_count); update_terminal; /* print a progress report */
}
out('{'); out_section(section_count); out('}');

@ In the \TEX/ part of a section, we simply copy the source text, except that
index entries are not copied and \CEE/ text within \pb\ is translated.

@<Translate the \T...@>= do
  switch (next_control=copy_TeX()) {
    case '|': init_stack; output_C(); break;
    case '@@': out('@@'); break;
    case TeX_string: case noop:
    case xref_roman: case xref_wildcard: case xref_typewriter:
    case section_name: loc-=2; next_control=get_next(); /* skip to \.{@@>} */
      if (next_control==TeX_string)
        err_print("! TeX string should be in C text only"); break;
@.TeX string should be...@>
    case thin_space: case math_break: case ord:
    case line_break: case big_line_break: case no_line_break: case join:
    case pseudo_semi: case macro_arg_open: case macro_arg_close:
    case output_defs_code:
        err_print("! You can't do that in TeX text"); break;
@.You can't do that...@>
  }
while (next_control<format_code);

@ When we get to the following code we have |next_control>=format_code|, and
the token memory is in its initial empty state.

@<Translate the d...@>=
space_checked=false;
while (next_control<=definition) { /* |format_code| or |definition| */
  init_stack;
  if (next_control==definition) @<Start a macro definition@>@;
  else @<Start a format definition@>@;
  outer_parse(); finish_C(format_visible); format_visible=true;
  doing_format=false;
}

@ The |finish_C| procedure outputs the translation of the current
scraps, preceded by the control sequence `\.{\\B}' and followed by the
control sequence `\.{\\par}'. It also restores the token and scrap
memories to their initial empty state.

A |force| token is appended to the current scraps before translation
takes place, so that the translation will normally end with \.{\\6} or
\.{\\7} (the \TEX/ macros for |force| and |big_force|). This \.{\\6} or
\.{\\7} is replaced by the concluding \.{\\par} or by \.{\\Y\\par}.

@c
static void
finish_C( /* finishes a definition or a \CEE/ part */
  boolean visible) /* |true| if we should produce \TeX\ output */
{
  text_pointer p; /* translation of the scraps */
  if (visible) {
    out_str("\\B"); app_tok(force); app_scrap(insert,no_math);
    p=translate();
@.\\B@>
    app(tok_flag+(int)(p-tok_start)); make_output(); /* output the list */
    if (out_ptr>out_buf+1)
      if (*(out_ptr-1)=='\\') {
@.\\6@>
@.\\7@>
@.\\Y@>
        if (*out_ptr=='6') out_ptr-=2;
        else if (*out_ptr=='7') *out_ptr='Y';
      }
    out_str("\\par"); finish_line();
  }
  if (text_ptr>max_text_ptr) max_text_ptr=text_ptr;
  if (tok_ptr>max_tok_ptr) max_tok_ptr=tok_ptr;
  if (scrap_ptr>max_scr_ptr) max_scr_ptr=scrap_ptr;
  tok_ptr=tok_mem+1; text_ptr=tok_start+1; scrap_ptr=scrap_info;
    /* forget the tokens and the scraps */
}

@ @<Predecl...@>=@+static void finish_C(boolean);

@ Keeping in line with the conventions of the \CEE/ preprocessor (and
otherwise contrary to the rules of \.{CWEB}) we distinguish here
between the case that `\.(' immediately follows an identifier and the
case that the two are separated by a space.  In the latter case, and
if the identifier is not followed by `\.(' at all, the replacement
text starts immediately after the identifier.  In the former case,
it starts after we scan the matching `\.)'.

@<Start a macro...@>= {
  if (save_line!=out_line || save_place!=out_ptr || space_checked) app(backup);
  if(!space_checked){emit_space_if_needed;save_position;}
  app_str("\\D"); /* this will produce `\#\&{define }' */
@.\\D@>
  if ((next_control=get_next())!=identifier)
    err_print("! Improper macro definition");
@.Improper macro definition@>
  else {
    app_cur_id(false);
    if (*loc=='(') {
      app('$');
  reswitch: switch (next_control=get_next()) {
      case '(': case ',': app(next_control); goto reswitch;
      case identifier: app_cur_id(false); goto reswitch;
      case ')': app(next_control); next_control=get_next(); break;
      case dot_dot_dot: app_str("\\,\\ldots\\,"); @.\\,@> @.\\ldots@>
        app_scrap(raw_int,no_math);
        if ((next_control=get_next())==')') {
          app(next_control); next_control=get_next(); break;
        } /* otherwise fall through */
      default: err_print("! Improper macro definition"); break;
      }
      app('$');
    }
    else next_control=get_next();
    app(break_space);
    app_scrap(dead,no_math); /* scrap won't take part in the parsing */
  }
}

@ @<Start a format...@>= {
  doing_format=true;
  if(*(loc-1)=='s' || *(loc-1)=='S') format_visible=false;
  if(!space_checked){emit_space_if_needed;save_position;}
  app_str("\\F"); /* this will produce `\&{format }' */
@.\\F@>
  next_control=get_next();
  if (next_control==identifier) {
    app(id_flag+(int)(id_lookup(id_first, id_loc,normal)-name_dir));
    app(break_space); /* this is syntactically separate from what follows */
    next_control=get_next();
    if (next_control==identifier) {
      app(id_flag+(int)(id_lookup(id_first, id_loc,normal)-name_dir));
      app_scrap(exp,maybe_math); app_scrap(semi,maybe_math);
      next_control=get_next();
    }
  }
  if (scrap_ptr!=scrap_info+2) err_print("! Improper format definition");
@.Improper format definition@>
}

@ Finally, when the \TEX/ and definition parts have been treated, we have
|next_control>=begin_C|. We will make the global variable |this_section|
point to the current section name, if it has a name.

@<Private...@>=
static name_pointer this_section; /* the current section name, or zero */

@ @<Translate the \CEE/...@>=
this_section=name_dir;
if (next_control<=section_name) {
  emit_space_if_needed; init_stack;
  if (next_control==begin_C) next_control=get_next();
  else {
    this_section=cur_section;
    @<Check that `\.{=}' or `\.{==}' follows this section name, and
      emit the scraps to start the section definition@>@;
  }
  while (next_control<=section_name) {
    outer_parse();
    @<Emit the scrap for a section name if present@>@;
  }
  finish_C(true);
}

@ The title of the section and an $\E$ or $\mathrel+\E$ are made
into a scrap that should not take part in the parsing.

@<Check that `\.{=}'...@>=
do next_control=get_next();
  while (next_control=='+'); /* allow optional `\.{+=}' */
if (next_control!='=' && next_control!=eq_eq)
  err_print("! You need an = sign after the section name");
@.You need an = sign...@>
else next_control=get_next();
if (out_ptr>out_buf+1 && *out_ptr=='Y' && *(out_ptr-1)=='\\') app(backup);
    /* the section name will be flush left */
@.\\Y@>
app(section_flag+(int)(this_section-name_dir));
cur_xref=(xref_pointer)this_section->xref;
if(cur_xref->num==file_flag) cur_xref=cur_xref->xlink;
app_str("${}");
if (cur_xref->num!=section_count+def_flag) {
  app_str("\\mathrel+"); /* section name is multiply defined */
  this_section=name_dir; /* so we won't give cross-reference info here */
}
app_str("\\E"); /* output an equivalence sign */
@.\\E@>
app_str("{}$");
app(force); app_scrap(dead,no_math);
        /* this forces a line break unless `\.{@@+}' follows */

@ @<Emit the scrap...@>=
if (next_control<section_name) {
  err_print("! You can't do that in C text");
@.You can't do that...@>
  next_control=get_next();
}
else if (next_control==section_name) {
  app(section_flag+(int)(cur_section-name_dir));
  app_scrap(section_scrap,maybe_math);
  next_control=get_next();
}

@ Cross references relating to a named section are given
after the section ends.

@<Show cross...@>=
if (this_section>name_dir) {
  cur_xref=(xref_pointer)this_section->xref;
  if ((an_output=(cur_xref->num==file_flag))==true) cur_xref=cur_xref->xlink;
  if (cur_xref->num>def_flag)
    cur_xref=cur_xref->xlink; /* bypass current section number */
  footnote(def_flag); footnote(cite_flag); footnote(0);
}

@ The |footnote| procedure gives cross-reference information about
multiply defined section names (if the |flag| parameter is
|def_flag|), or about references to a section name
(if |flag==cite_flag|), or to its uses (if |flag==0|). It assumes that
|cur_xref| points to the first cross-reference entry of interest, and it
leaves |cur_xref| pointing to the first element not printed.  Typical outputs:
`\.{\\A101.}'; `\.{\\Us 370\\ET1009.}';
`\.{\\As 8, 27\\*\\ETs64.}'.

Note that the output of \.{CWEAVE} is not English-specific; users may
supply new definitions for the macros \.{\\A}, \.{\\As}, etc.

@c
static void
footnote( /* outputs section cross-references */
sixteen_bits flag)
{
  xref_pointer q=cur_xref; /* cross-reference pointer variable */
  if (q->num<=flag) return;
  finish_line(); out('\\');
@.\\A@>
@.\\Q@>
@.\\U@>
  out(flag==0? 'U': flag==cite_flag? 'Q': 'A');
  @<Output all the section numbers on the reference list |cur_xref|@>@;
  out('.');
}

@ @<Predecl...@>=@+static void footnote(sixteen_bits);

@ The following code distinguishes three cases, according as the number
of cross-references is one, two, or more than two. Variable |q| points
to the first cross-reference, and the last link is a zero.

@<Output all the section numbers...@>=
if (q->xlink->num>flag) out('s'); /* plural */
while (true) {
  out_section(cur_xref->num-flag);
  cur_xref=cur_xref->xlink; /* point to the next cross-reference to output */
  if (cur_xref->num<=flag) break;
  if (cur_xref->xlink->num>flag) out_str(", "); /* not the last */
  else {out_str("\\ET"); /* the last */
@.\\ET@>
  if (cur_xref != q->xlink) out('s'); /* the last of more than two */
  }
}

@ @<Output the code for the end of a section@>=
out_str("\\fi"); finish_line();
@.\\fi@>
flush_buffer(out_buf,false,false); /* insert a blank line, it looks nice */

@** Phase three processing.
We are nearly finished! \.{CWEAVE}'s only remaining task is to write out the
index, after sorting the identifiers and index entries.

If the user has set the |no_xref| flag (the \.{-x} option on the command line),
just finish off the page, omitting the index, section name list, and table of
contents.

@c
static void
phase_three(void) {
if (no_xref) {
  finish_line();
  out_str("\\end");
@.\\end@>
  finish_line();
}
else {
  phase=3; if (show_progress) fputs("\nWriting the index...",stdout);
@.Writing the index...@>
  finish_line();
  if ((idx_file=fopen(idx_file_name,"wb"))==NULL)
    fatal("! Cannot open index file ",idx_file_name);
@.Cannot open index file@>
  if (change_exists) {
    @<Tell about changed sections@>@; finish_line(); finish_line();
  }
  out_str("\\inx"); finish_line();
@.\\inx@>
  active_file=idx_file; /* change active file to the index file */
  @<Do the first pass of sorting@>@;
  @<Sort and output the index@>@;
  finish_line(); fclose(active_file); /* finished with |idx_file| */
  active_file=tex_file; /* switch back to |tex_file| for a tic */
  out_str("\\fin"); finish_line();
@.\\fin@>
  if ((scn_file=fopen(scn_file_name,"wb"))==NULL)
    fatal("! Cannot open section file ",scn_file_name);
@.Cannot open section file@>
  active_file=scn_file; /* change active file to section listing file */
  @<Output all the section names@>@;
  finish_line(); fclose(active_file); /* finished with |scn_file| */
  active_file=tex_file;
  if (group_found) out_str("\\con");@+else out_str("\\end");
@.\\con@>
@.\\end@>
  finish_line();
  fclose(active_file);
}
if (show_happiness) {
  if (show_progress) new_line;
  fputs("Done.",stdout);
}
check_complete(); /* was all of the change file used? */
}

@ @<Predecl...@>=@+static void phase_three(void);

@ Just before the index comes a list of all the changed sections, including
the index section itself.

@<Private...@>=
static sixteen_bits k_section; /* runs through the sections */

@ @<Tell about changed sections@>=
/* remember that the index is already marked as changed */
k_section=0;
while (!changed_section[++k_section]);
out_str("\\ch ");
@.\\ch@>
out_section(k_section);
while (k_section<section_count) {
  while (!changed_section[++k_section]);
  out_str(", "); out_section(k_section);
}
out('.');

@ A left-to-right radix sorting method is used, since this makes it easy to
adjust the collating sequence and since the running time will be at worst
proportional to the total length of all entries in the index. We put the
identifiers into different lists based on their first characters.
(Uppercase letters are put into the same list as the corresponding lowercase
letters, since we want to have `$t<\\{TeX}<\&{to}$'.) The
list for character |c| begins at location |bucket[c]| and continues through
the |blink| array.

@<Private...@>=
static name_pointer bucket[256];
static name_pointer next_name; /* successor of |cur_name| when sorting */
static name_pointer blink[max_names]; /* links in the buckets */

@ To begin the sorting, we go through all the hash lists and put each entry
having a nonempty cross-reference list into the proper bucket.

@<Do the first pass...@>= {
int c;
for (c=0; c<256; c++) bucket[c]=NULL;
for (h=hash; h<=hash_end; h++) {
  next_name=*h;
  while (next_name) {
    cur_name=next_name; next_name=cur_name->link;
    if (cur_name->xref!=(void *)xmem) {
      c=(cur_name->byte_start)[0];
      if (xisupper(c)) c=tolower(c);
      blink[cur_name-name_dir]=bucket[c]; bucket[c]=cur_name;
    }
  }
}
}

@ During the sorting phase we shall use the |cat| and |trans| arrays from
\.{CWEAVE}'s parsing algorithm and rename them |depth| and |head|. They now
represent a stack of identifier lists for all the index entries that have
not yet been output. The variable |sort_ptr| tells how many such lists are
present; the lists are output in reverse order (first |sort_ptr|, then
|sort_ptr-1|, etc.). The |j|th list starts at |head[j]|, and if the first
|k| characters of all entries on this list are known to be equal we have
|depth[j]==k|.

@<Rest of |trans_plus| union@>=
name_pointer Head;

@ @d depth cat /* reclaims memory that is no longer needed for parsing */
@d head trans_plus.Head /* ditto */
@f sort_pointer int
@d sort_pointer scrap_pointer /* ditto */
@d sort_ptr scrap_ptr /* ditto */

@<Private...@>=
static eight_bits cur_depth; /* depth of current buckets */
static char *cur_byte; /* index into |byte_mem| */
static sixteen_bits cur_val; /* current cross-reference number */
static sort_pointer max_sort_ptr; /* largest value of |sort_ptr| */

@ @<Set init...@>=
max_sort_ptr=scrap_info;

@ The desired alphabetic order is specified by the |collate| array; namely,
$|collate|[0]<|collate|[1]<\cdots<|collate|[100]$.

@<Private...@>=
static eight_bits collate[101+128]; /* collation order */
@^high-bit character handling@>

@ We use the order $\hbox{null}<\.\ <\hbox{other characters}<{}$\.\_${}<
\.A=\.a<\cdots<\.Z=\.z<\.0<\cdots<\.9.$ Warning: The collation mapping
needs to be changed if ASCII code is not being used.
@^ASCII code dependencies@>
@^high-bit character handling@>

We initialize |collate| by copying a few characters at a time, because
some \CEE/ compilers choke on long strings.

@<Set init...@>=
collate[0]=0;
memcpy((char *)collate+1,
  " \1\2\3\4\5\6\7\10\11\12\13\14\15\16\17",16);
/* 16 characters + 1 = 17 */
memcpy((char *)collate+17,
  "\20\21\22\23\24\25\26\27\30\31\32\33\34\35\36\37",16);
/* 16 characters + 17 = 33 */
memcpy((char *)collate+33,
  "!\42#$%&'()*+,-./:;<=>?@@[\\]^`{|}~_",32);
/* 32 characters + 33 = 65 */
memcpy((char *)collate+65,
  "abcdefghijklmnopqrstuvwxyz0123456789",36);
/* (26 + 10) characters + 65 = 101 */
memcpy((char *)collate+101,
  "\200\201\202\203\204\205\206\207\210\211\212\213\214\215\216\217",16);
/* 16 characters + 101 = 117 */
memcpy((char *)collate+117,
  "\220\221\222\223\224\225\226\227\230\231\232\233\234\235\236\237",16);
/* 16 characters + 117 = 133 */
memcpy((char *)collate+133,
  "\240\241\242\243\244\245\246\247\250\251\252\253\254\255\256\257",16);
/* 16 characters + 133 = 149 */
memcpy((char *)collate+149,
  "\260\261\262\263\264\265\266\267\270\271\272\273\274\275\276\277",16);
/* 16 characters + 149 = 165 */
memcpy((char *)collate+165,
  "\300\301\302\303\304\305\306\307\310\311\312\313\314\315\316\317",16);
/* 16 characters + 165 = 181 */
memcpy((char *)collate+181,
  "\320\321\322\323\324\325\326\327\330\331\332\333\334\335\336\337",16);
/* 16 characters + 181 = 197 */
memcpy((char *)collate+197,
  "\340\341\342\343\344\345\346\347\350\351\352\353\354\355\356\357",16);
/* 16 characters + 197 = 213 */
memcpy((char *)collate+213,
  "\360\361\362\363\364\365\366\367\370\371\372\373\374\375\376\377",16);
/* 16 characters + 213 = 229 */

@ Procedure |unbucket| goes through the buckets and adds nonempty lists
to the stack, using the collating sequence specified in the |collate| array.
The parameter to |unbucket| tells the current depth in the buckets.
Any two sequences that agree in their first 255 character positions are
regarded as identical.

@d infinity 255 /* $\infty$ (approximately) */

@c
static void
unbucket( /* empties buckets having depth |d| */
eight_bits d)
{
  int c; /* index into |bucket|; cannot be a simple |char| because of sign
    comparison below */
  for (c=100+128; c>= 0; c--) if (bucket[collate[c]]) {
@^high-bit character handling@>
    if (sort_ptr>=scrap_info_end) overflow("sorting");
    sort_ptr++;
    if (sort_ptr>max_sort_ptr) max_sort_ptr=sort_ptr;
    if (c==0) sort_ptr->depth=infinity;
    else sort_ptr->depth=d;
    sort_ptr->head=bucket[collate[c]]; bucket[collate[c]]=NULL;
  }
}

@ @<Predecl...@>=@+static void unbucket(eight_bits);

@ @<Sort and output...@>=
sort_ptr=scrap_info; unbucket(1);
while (sort_ptr>scrap_info) {
  cur_depth=sort_ptr->depth;
  if (blink[sort_ptr->head-name_dir]==0 || cur_depth==infinity)
    @<Output index entries for the list at |sort_ptr|@>@;
  else @<Split the list at |sort_ptr| into further lists@>@;
}

@ @<Split the list...@>= {
  int c;
  next_name=sort_ptr->head;
  do {
    cur_name=next_name; next_name=blink[cur_name-name_dir];
    cur_byte=cur_name->byte_start+cur_depth;
    if (cur_byte==(cur_name+1)->byte_start) c=0; /* hit end of the name */
    else {
      c=*cur_byte;
      if (xisupper(c)) c=tolower(c);
    }
  blink[cur_name-name_dir]=bucket[c]; bucket[c]=cur_name;
  } while (next_name);
  --sort_ptr; unbucket(cur_depth+1);
}

@ @<Output index...@>= {
  cur_name=sort_ptr->head;
  do {
    out_str("\\I");
@.\\I@>
    @<Output the name at |cur_name|@>@;
    @<Output the cross-references at |cur_name|@>@;
    cur_name=blink[cur_name-name_dir];
  } while (cur_name);
  --sort_ptr;
}

@ @<Output the name...@>=
switch (cur_name->ilk) {@+char *j;@+@t}\6{\4@>
  case normal: case func_template:
    if (is_tiny(cur_name)) out_str("\\|");
    else {
      for (j=cur_name->byte_start;j<(cur_name+1)->byte_start;j++)
        if (xislower(*j)) goto lowcase;
      out_str("\\."); break;
lowcase: out_str("\\\\");
    }
    break;
@.\\|@>
@.\\.@>
@.\\\\@>
  case wildcard: out_str("\\9");@+ goto not_an_identifier;
@.\\9@>
  case typewriter: out_str("\\.");
@.\\.@>
  case roman: not_an_identifier: out_name(cur_name,false); goto name_done;
  case custom:
    out_str("$\\");
    for (j=cur_name->byte_start;j<(cur_name+1)->byte_start;j++)
      out(*j=='_'? 'x': *j=='$'? 'X': *j);
    out('$');
    goto name_done;
  default: out_str("\\&");
@.\\\&@>
}
out_name(cur_name,true);
name_done:@;

@ Section numbers that are to be underlined are enclosed in
`\.{\\[}$\,\ldots\,$\.]'.

@<Output the cross-references...@>=
@<Invert the cross-reference list at |cur_name|, making |cur_xref| the head@>@;
do {
  out_str(", "); cur_val=cur_xref->num;
  if (cur_val<def_flag) out_section(cur_val);
  else {out_str("\\["); out_section(cur_val-def_flag); out(']');}
@.\\[@>
  cur_xref=cur_xref->xlink;
} while (cur_xref!=xmem);
out('.'); finish_line();

@ List inversion is best thought of as popping elements off one stack and
pushing them onto another. In this case |cur_xref| will be the head of
the stack that we push things onto.

@<Private...@>=
static xref_pointer next_xref, this_xref;
  /* pointer variables for rearranging a list */

@ @<Invert the cross-reference list at |cur_name|, making |cur_xref| the head@>=
this_xref=(xref_pointer)cur_name->xref; cur_xref=xmem;
do {
  next_xref=this_xref->xlink; this_xref->xlink=cur_xref;
  cur_xref=this_xref; this_xref=next_xref;
} while (this_xref!=xmem);

@ The following recursive procedure walks through the tree of section names and
prints them.
@^recursion@>

@c
static void
section_print( /* print all section names in subtree |p| */
name_pointer p)
{
  if (p) {
    section_print(p->llink); out_str("\\I");
@.\\I@>
    tok_ptr=tok_mem+1; text_ptr=tok_start+1; scrap_ptr=scrap_info; init_stack;
    app(section_flag+(int)(p-name_dir)); make_output();
    footnote(cite_flag);
    footnote(0); /* |cur_xref| was set by |make_output| */
    finish_line();@/
    section_print(p->rlink);
  }
}

@ @<Predecl...@>=@+static void section_print(name_pointer);

@ @<Output all the section names@>=section_print(root);

@ Because on some systems the difference between two pointers is a |ptrdiff_t|
rather than an |int|, we use \.{\%td} to print these quantities.

@c
void
print_stats(void) {
  puts("\nMemory usage statistics:");
@.Memory usage statistics:@>
  printf("%td names (out of %ld)\n",
            (ptrdiff_t)(name_ptr-name_dir),(long)max_names);
  printf("%td cross-references (out of %ld)\n",
            (ptrdiff_t)(xref_ptr-xmem),(long)max_refs);
  printf("%td bytes (out of %ld)\n",
            (ptrdiff_t)(byte_ptr-byte_mem),(long)max_bytes);
  puts("Parsing:");
  printf("%td scraps (out of %ld)\n",
            (ptrdiff_t)(max_scr_ptr-scrap_info),(long)max_scraps);
  printf("%td texts (out of %ld)\n",
            (ptrdiff_t)(max_text_ptr-tok_start),(long)max_texts);
  printf("%td tokens (out of %ld)\n",
            (ptrdiff_t)(max_tok_ptr-tok_mem),(long)max_toks);
  printf("%td levels (out of %ld)\n",
            (ptrdiff_t)(max_stack_ptr-stack),(long)stack_size);
  puts("Sorting:");
  printf("%td levels (out of %ld)\n",
            (ptrdiff_t)(max_sort_ptr-scrap_info),(long)max_scraps);
}

@** Index.
If you have read and understood the code for Phase III above, you know what
is in this index and how it got here. All sections in which an identifier is
used are listed with that identifier, except that reserved words are
indexed only when they appear in format definitions, and the appearances
of identifiers in section names are not indexed. Underlined entries
correspond to where the identifier was declared. Error messages, control
sequences put into the output, and a few
other things like ``recursion'' are indexed here too.