Source

calendar / calendar.el

Full commit
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
;;; calendar.el --- calendar functions

;; Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1997,
;;   2000, 2001, 2002, 2003, 2004, 2005, 2006  Free Software Foundation, Inc.

;; Author: Edward M. Reingold <reingold@cs.uiuc.edu>
;; Maintainer: Glenn Morris <rgm@gnu.org>
;; Keywords: calendar
;; Human-Keywords: calendar, Gregorian calendar, diary, holidays

;; This file is part of XEmacs.

;; XEmacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; XEmacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with XEmacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Synched up with: FSF Emacs 22.1 CVS 2006-09-15

;;; Commentary:

;; This collection of functions implements a calendar window.  It
;; generates a calendar for the current month, together with the
;; previous and coming months, or for any other three-month period.
;; The calendar can be scrolled forward and backward in the window to
;; show months in the past or future; the cursor can move forward and
;; backward by days, weeks, or months, making it possible, for
;; instance, to jump to the date a specified number of days, weeks, or
;; months from the date under the cursor.  The user can display a list
;; of holidays and other notable days for the period shown; the
;; notable days can be marked on the calendar, if desired.  The user
;; can also specify that dates having corresponding diary entries (in
;; a file that the user specifies) be marked; the diary entries for
;; any date can be viewed in a separate window.  The diary and the
;; notable days can be viewed independently of the calendar.  Dates
;; can be translated from the (usual) Gregorian calendar to the day of
;; the year/days remaining in year, to the ISO commercial calendar, to
;; the Julian (old style) calendar, to the Hebrew calendar, to the
;; Islamic calendar, to the Baha'i calendar, to the French
;; Revolutionary calendar, to the Mayan calendar, to the Chinese
;; calendar, to the Coptic calendar, to the Ethiopic calendar, and to
;; the astronomical (Julian) day number.  When floating point is
;; available, times of sunrise/sunset can be displayed, as can the
;; phases of the moon.  Appointment notification for diary entries is
;; available.  Calendar printing via LaTeX is available.

;; The following files are part of the calendar/diary code:

;;       appt.el                       Appointment notification
;;       cal-china.el                  Chinese calendar
;;       cal-coptic.el                 Coptic/Ethiopic calendars
;;       cal-dst.el                    Daylight savings time rules
;;       cal-hebrew.el                 Hebrew calendar
;;       cal-islam.el                  Islamic calendar
;;       cal-bahai.el                  Baha'i calendar
;;       cal-iso.el                    ISO calendar
;;       cal-julian.el                 Julian/astronomical calendars
;;       cal-mayan.el                  Mayan calendars
;;       cal-menu.el                   Menu support
;;       cal-move.el                   Movement in the calendar
;;       cal-persia.el                 Persian calendar
;;       cal-tex.el                    Calendars in LaTeX
;;       cal-x.el                      X-windows dedicated frame functions
;;       diary-lib.el                  Diary functions
;;       holidays.el                   Holiday functions
;;       cal-french.el                 French Revolutionary calendar
;;       lunar.el                      Phases of the moon
;;       solar.el                      Sunrise/sunset, equinoxes/solstices

;; Technical details of all the calendrical calculations can be found in
;; ``Calendrical Calculations: The Millennium Edition'' by Edward M. Reingold
;; and Nachum Dershowitz, Cambridge University Press (2001).

;; An earlier version of the technical details appeared in
;; ``Calendrical Calculations'' by Nachum Dershowitz and Edward M. Reingold,
;; Software--Practice and Experience, Volume 20, Number 9 (September, 1990),
;; pages 899-928, and in ``Calendrical Calculations, Part II: Three Historical
;; Calendars'' by E. M. Reingold,  N. Dershowitz, and S. M. Clamen,
;; Software--Practice and Experience, Volume 23, Number 4 (April, 1993),
;; pages 383-404.

;; Hard copies of these two papers can be obtained by sending email to
;; reingold@cs.uiuc.edu with the SUBJECT "send-paper-cal" (no quotes) and
;; the message BODY containing your mailing address (snail).

;; Comments, corrections, and improvements should be sent to
;;  Edward M. Reingold               Department of Computer Science
;;  (217) 333-6733                   University of Illinois at Urbana-Champaign
;;  reingold@cs.uiuc.edu             1304 West Springfield Avenue
;;                                   Urbana, Illinois 61801

;;; Code:

(eval-and-compile
  (require 'cal-compat))

(defvar displayed-month)
(defvar displayed-year)
(defvar calendar-month-name-array)
(defvar calendar-starred-day)

(defun calendar-version ()
  (interactive)
  (message "Version 6, October 12, 1995"))

(defgroup calendar nil
  "Calendar and time management support."
  :group 'applications)

(defgroup diary nil
  "Emacs diary."
  :group 'calendar)

(defgroup appt nil
  "Appointment notification."
  :tag "Appointments"
  :group 'calendar)

(defgroup holidays nil
  "Holidays support in calendar."
  :group 'calendar
  :prefix "calendar-"
  :group 'local)

(defgroup chinese-calendar nil
  "Chinese calendar support."
  :group 'calendar)

(defgroup calendar-tex nil
  "Options for printing calendar with LaTeX."
  :prefix "cal-tex-"
  :group 'calendar)

(defgroup calendar-hooks nil
  "Calendar hooks."
  :prefix "calendar-"
  :group 'calendar)

;;;###autoload
(defconst calendar-buffer "*Calendar*"
  "Name of the buffer used for the calendar.")

;;;###autoload
(defcustom calendar-offset 0
  "The offset of the principal month from the center of the calendar window.
0 means the principal month is in the center (default), -1 means on the left,
+1 means on the right.  Larger (or smaller) values push the principal month off
the screen."
  :type 'integer
  :group 'calendar)

;;;###autoload
(defcustom view-diary-entries-initially nil
  "Non-nil means display current date's diary entries on entry to calendar.
The diary is displayed in another window when the calendar is first displayed,
if the current date is visible.  The number of days of diary entries displayed
is governed by the variable `number-of-diary-entries'.  This variable can
be overridden by the value of `calendar-setup'."
  :type 'boolean
  :group 'diary)

;;;###autoload
(defcustom mark-diary-entries-in-calendar nil
  "Non-nil means mark dates with diary entries, in the calendar window.
The marking symbol is specified by the variable `diary-entry-marker'."
  :type 'boolean
  :group 'diary)

;;;###autoload
(defcustom calendar-remove-frame-by-deleting nil
  "Determine how the calendar mode removes a frame no longer needed.
If nil, make an icon of the frame.  If non-nil, delete the frame."
  :type 'boolean
  :group 'view)

(defvar diary-face 'diary
  "Face name to use for diary entries.")
(defface diary
  '((((class color) (background light))
     (:foreground "red"))
    (((class color) (background dark))
     (:foreground "yellow"))
    (t
     (:weight bold t)))
  "Face for highlighting diary entries."
  :group 'diary)
;; backward-compatibility alias
(put 'diary-face 'face-alias 'diary)

(defface calendar-today-face
  '((t (:underline t)))
  "Face for indicating today's date."
  :group 'diary)
;; backward-compatibility alias


(defface holiday-face
  '((((class color) (background light))
     (:background "pink"))
    (((class color) (background dark))
     (:background "chocolate4"))
    (t
      (:inverse-video t)))
  "Face for indicating dates that have holidays."
  :group 'diary)
;; backward-compatibility alias

(defcustom diary-entry-marker
  (if (not (display-color-p))
      "+"
    'diary)
  "How to mark dates that have diary entries.
The value can be either a single-character string or a face."
  :type '(choice string face)
  :group 'diary)

(defcustom calendar-today-marker
  (if (not (display-color-p))
      "="
    'calendar-today-face)
  "How to mark today's date in the calendar.
The value can be either a single-character string or a face.
Marking today's date is done only if you set up `today-visible-calendar-hook'
to request that."
  :type '(choice string face)
  :group 'calendar)

(defcustom calendar-holiday-marker
  (if (not (display-color-p))
      "*"
    'holiday-face)
  "How to mark notable dates in the calendar.
The value can be either a single-character string or a face."
  :type '(choice string face)
  :group 'calendar)

;;;###autoload
(defcustom view-calendar-holidays-initially nil
  "Non-nil means display holidays for current three month period on entry.
The holidays are displayed in another window when the calendar is first
displayed."
  :type 'boolean
  :group 'holidays)

;;;###autoload
(defcustom mark-holidays-in-calendar nil
  "Non-nil means mark dates of holidays in the calendar window.
The marking symbol is specified by the variable `calendar-holiday-marker'."
  :type 'boolean
  :group 'holidays)

;;;###autoload
(defcustom all-hebrew-calendar-holidays nil
  "If nil, show only major holidays from the Hebrew calendar.
This means only those Jewish holidays that appear on secular calendars.

If t, show all the holidays that would appear in a complete Hebrew calendar."
  :type 'boolean
  :group 'holidays)

;;;###autoload
(defcustom all-christian-calendar-holidays nil
  "If nil, show only major holidays from the Christian calendar.
This means only those Christian holidays that appear on secular calendars.

If t, show all the holidays that would appear in a complete Christian
calendar."
  :type 'boolean
  :group 'holidays)

;;;###autoload
(defcustom all-islamic-calendar-holidays nil
  "If nil, show only major holidays from the Islamic calendar.
This means only those Islamic holidays that appear on secular calendars.

If t, show all the holidays that would appear in a complete Islamic
calendar."
  :type 'boolean
  :group 'holidays)

(defcustom diary-file-name-prefix-function (function (lambda (str) str))
  "The function that will take a diary file name and return the desired prefix."
  :type 'function
  :group 'diary)

;;;###autoload
(defcustom all-bahai-calendar-holidays nil
  "If nil, show only major holidays from the Baha'i calendar.
These are the days on which work and school must be suspended.

If t, show all the holidays that would appear in a complete Baha'i
calendar."
  :type 'boolean
  :group 'holidays)

;;;###autoload
(defcustom calendar-load-hook nil
  "List of functions to be called after the calendar is first loaded.
This is the place to add key bindings to `calendar-mode-map'."
  :type 'hook
  :group 'calendar-hooks)

;;;###autoload
(defcustom initial-calendar-window-hook nil
  "List of functions to be called when the calendar window is first opened.
The functions invoked are called after the calendar window is opened, but
once opened is never called again.  Leaving the calendar with the `q' command
and reentering it will cause these functions to be called again."
  :type 'hook
  :group 'calendar-hooks)

;;;###autoload
(defcustom today-visible-calendar-hook nil
  "List of functions called whenever the current date is visible.
This can be used, for example, to replace today's date with asterisks; a
function `calendar-star-date' is included for this purpose:
    (setq today-visible-calendar-hook 'calendar-star-date)
It can also be used to mark the current date with `calendar-today-marker';
a function is also provided for this:
    (setq today-visible-calendar-hook 'calendar-mark-today)

The corresponding variable `today-invisible-calendar-hook' is the list of
functions called when the calendar function was called when the current
date is not visible in the window.

Other than the use of the provided functions, the changing of any
characters in the calendar buffer by the hooks may cause the failure of the
functions that move by days and weeks."
  :type 'hook
  :group 'calendar-hooks)

;;;###autoload
(defcustom today-invisible-calendar-hook nil
  "List of functions called whenever the current date is not visible.

The corresponding variable `today-visible-calendar-hook' is the list of
functions called when the calendar function was called when the current
date is visible in the window.

Other than the use of the provided functions, the changing of any
characters in the calendar buffer by the hooks may cause the failure of the
functions that move by days and weeks."
  :type 'hook
  :group 'calendar-hooks)

;;;###autoload
(defcustom calendar-move-hook nil
  "List of functions called whenever the cursor moves in the calendar.

For example,

  (add-hook 'calendar-move-hook (lambda () (diary-view-entries 1)))

redisplays the diary for whatever date the cursor is moved to."
  :type 'hook
  :group 'calendar-hooks)

;;;###autoload
(defcustom diary-file "~/diary"
  "Name of the file in which one's personal diary of dates is kept.

The file's entries are lines beginning with any of the forms
specified by the variable `american-date-diary-pattern', by default:

            MONTH/DAY
            MONTH/DAY/YEAR
            MONTHNAME DAY
            MONTHNAME DAY, YEAR
            DAYNAME

with the remainder of the line being the diary entry string for
that date.  MONTH and DAY are one or two digit numbers, YEAR is a
number and may be written in full or abbreviated to the final two
digits (if `abbreviated-calendar-year' is non-nil).  MONTHNAME
and DAYNAME can be spelled in full (as specified by the variables
`calendar-month-name-array' and `calendar-day-name-array'),
abbreviated (as specified by `calendar-month-abbrev-array' and
`calendar-day-abbrev-array') with or without a period,
capitalized or not.  Any of DAY, MONTH, or MONTHNAME, YEAR can be
`*' which matches any day, month, or year, respectively. If the
date does not contain a year, it is generic and applies to any
year.  A DAYNAME entry applies to the appropriate day of the week
in every week.

The European style (in which the day precedes the month) can be
used instead, if you execute `european-calendar' when in the
calendar, or set `european-calendar-style' to t in your .emacs
file.  The European forms (see `european-date-diary-pattern') are

            DAY/MONTH
            DAY/MONTH/YEAR
            DAY MONTHNAME
            DAY MONTHNAME YEAR
            DAYNAME

To revert to the default American style from the European style, execute
`american-calendar' in the calendar.

A diary entry can be preceded by the character
`diary-nonmarking-symbol' (ordinarily `&') to make that entry
nonmarking--that is, it will not be marked on dates in the calendar
window but will appear in a diary window.

Multiline diary entries are made by indenting lines after the first with
either a TAB or one or more spaces.

Lines not in one the above formats are ignored.  Here are some sample diary
entries (in the default American style):

     12/22/1988 Twentieth wedding anniversary!!
     &1/1. Happy New Year!
     10/22 Ruth's birthday.
     21: Payday
     Tuesday--weekly meeting with grad students at 10am
              Supowit, Shen, Bitner, and Kapoor to attend.
     1/13/89 Friday the thirteenth!!
     &thu 4pm squash game with Lloyd.
     mar 16 Dad's birthday
     April 15, 1989 Income tax due.
     &* 15 time cards due.

If the first line of a diary entry consists only of the date or day name with
no trailing blanks or punctuation, then that line is not displayed in the
diary window; only the continuation lines is shown.  For example, the
single diary entry

     02/11/1989
      Bill Blattner visits Princeton today
      2pm Cognitive Studies Committee meeting
      2:30-5:30 Lizzie at Lawrenceville for `Group Initiative'
      4:00pm Jamie Tappenden
      7:30pm Dinner at George and Ed's for Alan Ryan
      7:30-10:00pm dance at Stewart Country Day School

will appear in the diary window without the date line at the beginning.  This
facility allows the diary window to look neater, but can cause confusion if
used with more than one day's entries displayed.

Diary entries can be based on Lisp sexps.  For example, the diary entry

      %%(diary-block 11 1 1990 11 10 1990) Vacation

causes the diary entry \"Vacation\" to appear from November 1 through
November 10, 1990.  Other functions available are `diary-float',
`diary-anniversary', `diary-cyclic', `diary-day-of-year',
`diary-iso-date', `diary-french-date', `diary-hebrew-date',
`diary-islamic-date', `diary-bahai-date', `diary-mayan-date',
`diary-chinese-date', `diary-coptic-date', `diary-ethiopic-date',
`diary-persian-date', `diary-yahrzeit', `diary-sunrise-sunset',
`diary-phases-of-moon', `diary-parasha', `diary-omer',
`diary-rosh-hodesh', and `diary-sabbath-candles'.  See the
documentation for the function `list-sexp-diary-entries' for more
details.

Diary entries based on the Hebrew, the Islamic and/or the Baha'i
calendar are also possible, but because these are somewhat slow, they
are ignored unless you set the `nongregorian-diary-listing-hook' and
the `nongregorian-diary-marking-hook' appropriately.  See the
documentation for these functions for details.

Diary files can contain directives to include the contents of other files; for
details, see the documentation for the variable `list-diary-entries-hook'."
  :type 'file
  :group 'diary)

;;;###autoload
(defcustom diary-nonmarking-symbol "&"
  "Symbol indicating that a diary entry is not to be marked in the calendar."
  :type 'string
  :group 'diary)

;;;###autoload
(defcustom hebrew-diary-entry-symbol "H"
  "Symbol indicating a diary entry according to the Hebrew calendar."
  :type 'string
  :group 'diary)

;;;###autoload
(defcustom islamic-diary-entry-symbol "I"
  "Symbol indicating a diary entry according to the Islamic calendar."
  :type 'string
  :group 'diary)

;;;###autoload
(defcustom bahai-diary-entry-symbol "B"
  "Symbol indicating a diary entry according to the Baha'i calendar."
  :type 'string
  :group 'diary)

;;;###autoload
(defcustom diary-include-string "#include"
  "The string indicating inclusion of another file of diary entries.
See the documentation for the function `include-other-diary-files'."
  :type 'string
  :group 'diary)

(defcustom diary-glob-file-regexp-prefix "^\\#"
  "The regular expression that gets pre-pended to each of the attribute-regexp's for file-wide specifiers."
  :type 'regexp
  :group 'diary)

(defcustom diary-face-attrs
  '((" *\\[foreground:\\([-a-z]+\\)\\]$" 1 :foreground string)
    (" *\\[background:\\([-a-z]+\\)\\]$" 1 :background string)
    (" *\\[width:\\([-a-z]+\\)\\]$" 1 :width symbol)
    (" *\\[height:\\([-0-9a-z]+\\)\\]$" 1 :height int)
    (" *\\[weight:\\([-a-z]+\\)\\]$" 1 :weight symbol)
    (" *\\[slant:\\([-a-z]+\\)\\]$" 1 :slant symbol)
    ;; XEmacs change, we don't support underline faces
    (" *\\[underline:\\([-a-z]+\\)\\]$" 1 :underline tnil)
    (" *\\[overline:\\([-a-z]+\\)\\]$" 1 :overline stringtnil)
    (" *\\[strike-through:\\([-a-z]+\\)\\]$" 1 :strike-through stringtnil)
    (" *\\[inverse-video:\\([-a-z]+\\)\\]$" 1 :inverse-video tnil)
    (" *\\[face:\\([-0-9a-z]+\\)\\]$" 1 :face string)
    (" *\\[font:\\([-a-z0-9]+\\)\\]$" 1 :font string)
    ;; Unsupported.
;;;    (" *\\[box:\\([-a-z]+\\)\\]$" 1 :box)
;;;    (" *\\[stipple:\\([-a-z]+\\)\\]$" 1 :stipple)
    )
  "A list of (regexp regnum attr attrtype) lists where the
regexp says how to find the tag, the regnum says which
parenthetical sub-regexp this regexp looks for, and the attr says
which attribute of the face (or that this _is_ a face) is being
modified."
  :type 'sexp
  :group 'diary)

(defcustom diary-file-name-prefix nil
  "If non-nil each diary entry is prefixed with the name of the file where it is defined."
  :type 'boolean
  :group 'diary)

;;;###autoload
(defcustom sexp-diary-entry-symbol "%%"
  "The string used to indicate a sexp diary entry in `diary-file'.
See the documentation for the function `list-sexp-diary-entries'."
  :type 'string
  :group 'diary)

;;;###autoload
(defcustom abbreviated-calendar-year t
  "Interpret a two-digit year DD in a diary entry as either 19DD or 20DD.
For the Gregorian calendar; similarly for the Hebrew, Islamic and
Baha'i calendars.  If this variable is nil, years must be written in
full."
  :type 'boolean
  :group 'diary)

;;;###autoload
(defcustom european-calendar-style nil
  "Use the European style of dates in the diary and in any displays.
If this variable is t, a date 1/2/1990 would be interpreted as February 1,
1990.  The default European date styles (see `european-date-diary-pattern')
are

            DAY/MONTH
            DAY/MONTH/YEAR
            DAY MONTHNAME
            DAY MONTHNAME YEAR
            DAYNAME

Names can be capitalized or not, written in full (as specified by the
variable `calendar-day-name-array'), or abbreviated (as specified by
`calendar-day-abbrev-array') with or without a period.

Setting this variable directly does not take effect (if the
calendar package is already loaded).  Rather, use either
\\[customize] or the functions `european-calendar' and
`american-calendar'."
  :type 'boolean
  ;; Without :initialize (require 'calendar) throws an error because
  ;; american-calendar is undefined at this point.
:initialize 'custom-initialize-default
:set (lambda (symbol value)
         (if value
             (european-calendar)
           (american-calendar)))
  :group 'diary)

;;;###autoload
(defcustom american-date-diary-pattern
  '((month "/" day "[^/0-9]")
    (month "/" day "/" year "[^0-9]")
    (monthname " *" day "[^,0-9]")
    (monthname " *" day ", *" year "[^0-9]")
    (dayname "\\W"))
  "List of pseudo-patterns describing the American patterns of date used.
See the documentation of `diary-date-forms' for an explanation."
  :type '(repeat (choice (cons :tag "Backup"
			       :value (backup . nil)
			       (const backup)
			       (repeat (list :inline t :format "%v"
					     (symbol :tag "Keyword")
					     (choice symbol regexp))))
			 (repeat (list :inline t :format "%v"
				       (symbol :tag "Keyword")
				       (choice symbol regexp)))))
  :group 'diary)

;;;###autoload
(defcustom european-date-diary-pattern
  '((day "/" month "[^/0-9]")
    (day "/" month "/" year "[^0-9]")
    (backup day " *" monthname "\\W+\\<\\([^*0-9]\\|\\([0-9]+[:aApP]\\)\\)")
    (day " *" monthname " *" year "[^0-9]")
    (dayname "\\W"))
  "List of pseudo-patterns describing the European patterns of date used.
See the documentation of `diary-date-forms' for an explanation."
  :type '(repeat (choice (cons :tag "Backup"
			       :value (backup . nil)
			       (const backup)
			       (repeat (list :inline t :format "%v"
					     (symbol :tag "Keyword")
					     (choice symbol regexp))))
			 (repeat (list :inline t :format "%v"
				       (symbol :tag "Keyword")
				       (choice symbol regexp)))))
  :group 'diary)

(defcustom diary-date-forms
  (if european-calendar-style
      european-date-diary-pattern
    american-date-diary-pattern)
  "List of pseudo-patterns describing the forms of date used in the diary.
The patterns on the list must be MUTUALLY EXCLUSIVE and should not match
any portion of the diary entry itself, just the date component.

A pseudo-pattern is a list of regular expressions and the keywords `month',
`day', `year', `monthname', and `dayname'.  The keyword `monthname' will
match the name of the month (see `calendar-month-name-array'), capitalized
or not, or its user-specified abbreviation (see `calendar-month-abbrev-array'),
followed by a period or not; it will also match `*'.  Similarly, `dayname'
will match the name of the day (see `calendar-day-name-array'), capitalized or
not, or its user-specified abbreviation (see `calendar-day-abbrev-array'),
followed by a period or not.  The keywords `month', `day', and `year' will
match those numerical values, preceded by arbitrarily many zeros; they will
also match `*'.

The matching of the diary entries with the date forms is done with the
standard syntax table from Fundamental mode, but with the `*' changed so
that it is a word constituent.

If, to be mutually exclusive, a pseudo-pattern must match a portion of the
diary entry itself, the first element of the pattern MUST be `backup'.  This
directive causes the date recognizer to back up to the beginning of the
current word of the diary entry, so in no case can the pattern match more than
a portion of the first word of the diary entry."
  :type '(repeat (choice (cons :tag "Backup"
			       :value (backup . nil)
			       (const backup)
			       (repeat (list :inline t :format "%v"
					     (symbol :tag "Keyword")
					     (choice symbol regexp))))
			 (repeat (list :inline t :format "%v"
				       (symbol :tag "Keyword")
				       (choice symbol regexp)))))
  :group 'diary)

;;;###autoload
(defcustom european-calendar-display-form
  '((if dayname (concat dayname ", ")) day " " monthname " " year)
  "Pseudo-pattern governing the way a date appears in the European style.
See the documentation of `calendar-date-display-form' for an explanation."
  :type 'sexp
  :group 'calendar)

;;;###autoload
(defcustom american-calendar-display-form
  '((if dayname (concat dayname ", ")) monthname " " day ", " year)
  "Pseudo-pattern governing the way a date appears in the American style.
See the documentation of `calendar-date-display-form' for an explanation."
  :type 'sexp
  :group 'calendar)

(defcustom calendar-date-display-form
  (if european-calendar-style
      european-calendar-display-form
    american-calendar-display-form)
  "Pseudo-pattern governing the way a date appears.

Used by the function `calendar-date-string', a pseudo-pattern is a list of
expressions that can involve the keywords `month', `day', and `year', all
numbers in string form, and `monthname' and `dayname', both alphabetic
strings.  For example, the ISO standard would use the pseudo- pattern

       '(year \"-\" month \"-\" day)

while a typical American form would be

       '(month \"/\" day \"/\" (substring year -2))

and

       '((format \"%9s, %9s %2s, %4s\" dayname monthname day year))

would give the usual American style in fixed-length fields.

See the documentation of the function `calendar-date-string'."
  :type 'sexp
  :group 'calendar)

(defun european-calendar ()
  "Set the interpretation and display of dates to the European style."
  (interactive)
  (setq european-calendar-style t)
  (setq calendar-date-display-form european-calendar-display-form)
  (setq diary-date-forms european-date-diary-pattern)
  (update-calendar-mode-line))

(defun american-calendar ()
  "Set the interpretation and display of dates to the American style."
  (interactive)
  (setq european-calendar-style nil)
  (setq calendar-date-display-form american-calendar-display-form)
  (setq diary-date-forms american-date-diary-pattern)
  (update-calendar-mode-line))

;;;###autoload
(defcustom print-diary-entries-hook 'lpr-buffer
  "List of functions called after a temporary diary buffer is prepared.
The buffer shows only the diary entries currently visible in the diary
buffer.  The default just does the printing.  Other uses might include, for
example, rearranging the lines into order by day and time, saving the buffer
instead of deleting it, or changing the function used to do the printing."
  :type 'hook
  :group 'diary)

;;;###autoload
(defcustom list-diary-entries-hook nil
  "List of functions called after diary file is culled for relevant entries.
It is to be used for diary entries that are not found in the diary file.

A function `include-other-diary-files' is provided for use as the value of
this hook.  This function enables you to use shared diary files together
with your own.  The files included are specified in the diary file by lines
of the form

        #include \"filename\"

This is recursive; that is, #include directives in files thus included are
obeyed.  You can change the \"#include\" to some other string by changing
the variable `diary-include-string'.  When you use `include-other-diary-files'
as part of the list-diary-entries-hook, you will probably also want to use the
function `mark-included-diary-files' as part of `mark-diary-entries-hook'.

For example, you could use

     (setq list-diary-entries-hook
       '(include-other-diary-files sort-diary-entries))
     (setq diary-display-hook 'fancy-diary-display)

in your `.emacs' file to cause the fancy diary buffer to be displayed with
diary entries from various included files, each day's entries sorted into
lexicographic order."
  :type 'hook
  :options '(include-other-diary-files sort-diary-entries)
  :group 'diary)

;;;###autoload
(defcustom diary-hook nil
  "List of functions called after the display of the diary.
Can be used for appointment notification."
  :type 'hook
  :group 'diary)

;;;###autoload
(defcustom diary-display-hook nil
  "List of functions that handle the display of the diary.
If nil (the default), `simple-diary-display' is used.  Use `ignore' for no
diary display.

Ordinarily, this just displays the diary buffer (with holidays indicated in
the mode line), if there are any relevant entries.  At the time these
functions are called, the variable `diary-entries-list' is a list, in order
by date, of all relevant diary entries in the form of ((MONTH DAY YEAR)
STRING), where string is the diary entry for the given date.  This can be
used, for example, a different buffer for display (perhaps combined with
holidays), or produce hard copy output.

A function `fancy-diary-display' is provided as an alternative
choice for this hook; this function prepares a special noneditable diary
buffer with the relevant diary entries that has neat day-by-day arrangement
with headings.  The fancy diary buffer will show the holidays unless the
variable `holidays-in-diary-buffer' is set to nil.  Ordinarily, the fancy
diary buffer will not show days for which there are no diary entries, even
if that day is a holiday; if you want such days to be shown in the fancy
diary buffer, set the variable `diary-list-include-blanks' to t."
  :type 'hook
  :options '(fancy-diary-display)
  :group 'diary)

;;;###autoload
(defcustom nongregorian-diary-listing-hook nil
  "List of functions called for listing diary file and included files.
As the files are processed for diary entries, these functions are used
to cull relevant entries.  You can use either or both of
`list-hebrew-diary-entries', `list-islamic-diary-entries' and
`list-bahai-diary-entries'.  The documentation for these functions
describes the style of such diary entries."
  :type 'hook
  :options '(list-hebrew-diary-entries
	     list-islamic-diary-entries
	     list-bahai-diary-entries)
  :group 'diary)

;;;###autoload
(defcustom mark-diary-entries-hook nil
  "List of functions called after marking diary entries in the calendar.

A function `mark-included-diary-files' is also provided for use as the
`mark-diary-entries-hook'; it enables you to use shared diary files together
with your own.  The files included are specified in the diary file by lines
of the form
        #include \"filename\"
This is recursive; that is, #include directives in files thus included are
obeyed.  You can change the \"#include\" to some other string by changing the
variable `diary-include-string'.  When you use `mark-included-diary-files' as
part of the mark-diary-entries-hook, you will probably also want to use the
function `include-other-diary-files' as part of `list-diary-entries-hook'."
  :type 'hook
  :options '(mark-included-diary-files)
  :group 'diary)

;;;###autoload
(defcustom nongregorian-diary-marking-hook nil
  "List of functions called for marking diary file and included files.
As the files are processed for diary entries, these functions are used
to cull relevant entries.  You can use either or both of
`mark-hebrew-diary-entries', `mark-islamic-diary-entries' and
`mark-bahai-diary-entries'.  The documentation for these functions
describes the style of such diary entries."
  :type 'hook
  :options '(mark-hebrew-diary-entries
	     mark-islamic-diary-entries
	     mark-bahai-diary-entries)
  :group 'diary)

;;;###autoload
(defcustom diary-list-include-blanks nil
  "If nil, do not include days with no diary entry in the list of diary entries.
Such days will then not be shown in the fancy diary buffer, even if they
are holidays."
  :type 'boolean
  :group 'diary)

;;;###autoload
(defcustom holidays-in-diary-buffer t
  "Non-nil means include holidays in the diary display.
The holidays appear in the mode line of the diary buffer, or in the
fancy diary buffer next to the date.  This slows down the diary functions
somewhat; setting it to nil makes the diary display faster."
  :type 'boolean
  :group 'holidays)

(defvar calendar-mark-ring nil)

;;;###autoload
(put 'general-holidays 'risky-local-variable t)
;;;###autoload
(defcustom general-holidays
  '((holiday-fixed 1 1 "New Year's Day")
    (holiday-float 1 1 3 "Martin Luther King Day")
    (holiday-fixed 2 2 "Groundhog Day")
    (holiday-fixed 2 14 "Valentine's Day")
    (holiday-float 2 1 3 "President's Day")
    (holiday-fixed 3 17 "St. Patrick's Day")
    (holiday-fixed 4 1 "April Fools' Day")
    (holiday-float 5 0 2 "Mother's Day")
    (holiday-float 5 1 -1 "Memorial Day")
    (holiday-fixed 6 14 "Flag Day")
    (holiday-float 6 0 3 "Father's Day")
    (holiday-fixed 7 4 "Independence Day")
    (holiday-float 9 1 1 "Labor Day")
    (holiday-float 10 1 2 "Columbus Day")
    (holiday-fixed 10 31 "Halloween")
    (holiday-fixed 11 11 "Veteran's Day")
    (holiday-float 11 4 4 "Thanksgiving"))
  "General holidays.  Default value is for the United States.
See the documentation for `calendar-holidays' for details."
  :type 'sexp
  :group 'holidays)

;;;###autoload
(put 'oriental-holidays 'risky-local-variable t)
;;;###autoload
(defcustom oriental-holidays
  '((if (fboundp 'atan)
	(holiday-chinese-new-year)))
  "Oriental holidays.
See the documentation for `calendar-holidays' for details."
  :type 'sexp
  :group 'holidays)

;;;###autoload
(put 'local-holidays 'risky-local-variable t)
;;;###autoload
(defcustom local-holidays nil
  "Local holidays.
See the documentation for `calendar-holidays' for details."
  :type 'sexp
  :group 'local
  :group 'holidays)

;;;###autoload
(put 'other-holidays 'risky-local-variable t)
;;;###autoload
(defcustom other-holidays nil
  "User defined holidays.
See the documentation for `calendar-holidays' for details."
  :type 'sexp
  :group 'holidays)

;;;###autoload
(put 'hebrew-holidays-1 'risky-local-variable t)
;;;###autoload
(defvar hebrew-holidays-1
  '((holiday-rosh-hashanah-etc)
    (if all-hebrew-calendar-holidays
        (holiday-julian
         11
         (let* ((m displayed-month)
                (y displayed-year)
                (year))
           (increment-calendar-month m y -1)
           (let ((year (extract-calendar-year
                        (calendar-julian-from-absolute
                         (calendar-absolute-from-gregorian
                          (list m 1 y))))))
             (if (zerop (% (1+ year) 4))
                 22
               21))) "\"Tal Umatar\" (evening)"))))

;;;###autoload
(put 'hebrew-holidays-2 'risky-local-variable t)
;;;###autoload
(defvar hebrew-holidays-2
  '((if all-hebrew-calendar-holidays
        (holiday-hanukkah)
      (holiday-hebrew 9 25 "Hanukkah"))
    (if all-hebrew-calendar-holidays
      (holiday-hebrew
       10
       (let ((h-year (extract-calendar-year
                      (calendar-hebrew-from-absolute
                       (calendar-absolute-from-gregorian
                        (list displayed-month 28 displayed-year))))))
         (if (= (% (calendar-absolute-from-hebrew (list 10 10 h-year))
                   7)
                6)
             11 10))
       "Tzom Teveth"))
    (if all-hebrew-calendar-holidays
        (holiday-hebrew 11 15 "Tu B'Shevat"))))

;;;###autoload
(put 'hebrew-holidays-3 'risky-local-variable t)
;;;###autoload
(defvar hebrew-holidays-3
  '((if all-hebrew-calendar-holidays
        (holiday-hebrew
         11
         (let ((m displayed-month)
               (y displayed-year))
           (increment-calendar-month m y 1)
           (let* ((h-year (extract-calendar-year
                           (calendar-hebrew-from-absolute
                            (calendar-absolute-from-gregorian
                             (list m
                                   (calendar-last-day-of-month m y)
                                   y)))))
                  (s-s
                   (calendar-hebrew-from-absolute
                    (if (=
                         (% (calendar-absolute-from-hebrew
                             (list 7 1 h-year))
                            7)
                         6)
                        (calendar-dayname-on-or-before
                         6 (calendar-absolute-from-hebrew
                            (list 11 17 h-year)))
                      (calendar-dayname-on-or-before
                       6 (calendar-absolute-from-hebrew
                          (list 11 16 h-year))))))
                  (day (extract-calendar-day s-s)))
             day))
         "Shabbat Shirah"))))

;;;###autoload
(put 'hebrew-holidays-4 'risky-local-variable t)
;;;###autoload
(defvar hebrew-holidays-4
  '((holiday-passover-etc)
    (if (and all-hebrew-calendar-holidays
             (let* ((m displayed-month)
                    (y displayed-year)
                    (year))
               (increment-calendar-month m y -1)
               (let ((year (extract-calendar-year
                            (calendar-julian-from-absolute
                             (calendar-absolute-from-gregorian
                              (list m 1 y))))))
                 (= 21 (% year 28)))))
        (holiday-julian 3 26 "Kiddush HaHamah"))
    (if all-hebrew-calendar-holidays
        (holiday-tisha-b-av-etc))))

;;;###autoload
(put 'hebrew-holidays 'risky-local-variable t)
;;;###autoload
(defcustom hebrew-holidays (append hebrew-holidays-1 hebrew-holidays-2
				hebrew-holidays-3 hebrew-holidays-4)
  "Jewish holidays.
See the documentation for `calendar-holidays' for details."
  :type 'sexp
  :group 'holidays)

;;;###autoload
(put 'christian-holidays 'risky-local-variable t)
;;;###autoload
(defcustom christian-holidays
  '((if all-christian-calendar-holidays
        (holiday-fixed 1 6 "Epiphany"))
    (holiday-easter-etc 0 "Easter Sunday")
    (holiday-easter-etc -2 "Good Friday")
    (holiday-easter-etc -46 "Ash Wednesday")
    (if all-christian-calendar-holidays
        (holiday-easter-etc -63 "Septuagesima Sunday"))
    (if all-christian-calendar-holidays
        (holiday-easter-etc -56 "Sexagesima Sunday"))
    (if all-christian-calendar-holidays
        (holiday-easter-etc -49 "Shrove Sunday"))
    (if all-christian-calendar-holidays
        (holiday-easter-etc -48 "Shrove Monday"))
    (if all-christian-calendar-holidays
        (holiday-easter-etc -47 "Shrove Tuesday"))
    (if all-christian-calendar-holidays
        (holiday-easter-etc -14 "Passion Sunday"))
    (if all-christian-calendar-holidays
        (holiday-easter-etc -7 "Palm Sunday"))
    (if all-christian-calendar-holidays
        (holiday-easter-etc -3 "Maundy Thursday"))
    (if all-christian-calendar-holidays
        (holiday-easter-etc 35 "Rogation Sunday"))
    (if all-christian-calendar-holidays
        (holiday-easter-etc 39 "Ascension Day"))
    (if all-christian-calendar-holidays
        (holiday-easter-etc 49 "Pentecost (Whitsunday)"))
    (if all-christian-calendar-holidays
        (holiday-easter-etc 50 "Whitmonday"))
    (if all-christian-calendar-holidays
        (holiday-easter-etc 56 "Trinity Sunday"))
    (if all-christian-calendar-holidays
        (holiday-easter-etc 60 "Corpus Christi"))
    (if all-christian-calendar-holidays
        (holiday-greek-orthodox-easter))
    (if all-christian-calendar-holidays
        (holiday-fixed 8 15 "Assumption"))
    (if all-christian-calendar-holidays
        (holiday-advent 0 "Advent"))
    (holiday-fixed 12 25 "Christmas")
    (if all-christian-calendar-holidays
        (holiday-julian 12 25 "Eastern Orthodox Christmas")))
  "Christian holidays.
See the documentation for `calendar-holidays' for details."
  :type 'sexp
  :group 'holidays)

;;;###autoload
(put 'islamic-holidays 'risky-local-variable t)
;;;###autoload
(defcustom islamic-holidays
  '((holiday-islamic
     1 1
     (format "Islamic New Year %d"
             (let ((m displayed-month)
                   (y displayed-year))
               (increment-calendar-month m y 1)
               (extract-calendar-year
                (calendar-islamic-from-absolute
                 (calendar-absolute-from-gregorian
                  (list
                   m (calendar-last-day-of-month m y) y)))))))
    (if all-islamic-calendar-holidays
        (holiday-islamic 1 10 "Ashura"))
    (if all-islamic-calendar-holidays
        (holiday-islamic 3 12 "Mulad-al-Nabi"))
    (if all-islamic-calendar-holidays
        (holiday-islamic 7 26 "Shab-e-Mi'raj"))
    (if all-islamic-calendar-holidays
        (holiday-islamic 8 15 "Shab-e-Bara't"))
    (holiday-islamic 9 1 "Ramadan Begins")
    (if all-islamic-calendar-holidays
        (holiday-islamic 9 27 "Shab-e Qadr"))
    (if all-islamic-calendar-holidays
        (holiday-islamic 10 1 "Id-al-Fitr"))
    (if all-islamic-calendar-holidays
        (holiday-islamic 12 10 "Id-al-Adha")))
  "Islamic holidays.
See the documentation for `calendar-holidays' for details."
  :type 'sexp
  :group 'holidays)

;;;###autoload
(put 'bahai-holidays 'risky-local-variable t)
;;;###autoload
(defcustom bahai-holidays
  '((holiday-fixed
     3 21
     (format "Baha'i New Year (Naw-Ruz) %d" (- displayed-year (1- 1844))))
    (holiday-fixed  4 21 "First Day of Ridvan")
    (if all-bahai-calendar-holidays
	(holiday-fixed  4 22 "Second Day of Ridvan"))
    (if all-bahai-calendar-holidays
	(holiday-fixed  4 23 "Third Day of Ridvan"))
    (if all-bahai-calendar-holidays
	(holiday-fixed  4 24 "Fourth Day of Ridvan"))
    (if all-bahai-calendar-holidays
	(holiday-fixed  4 25 "Fifth Day of Ridvan"))
    (if all-bahai-calendar-holidays
	(holiday-fixed  4 26 "Sixth Day of Ridvan"))
    (if all-bahai-calendar-holidays
	(holiday-fixed  4 27 "Seventh Day of Ridvan"))
    (if all-bahai-calendar-holidays
	(holiday-fixed  4 28 "Eighth Day of Ridvan"))
    (holiday-fixed  4 29 "Ninth Day of Ridvan")
    (if all-bahai-calendar-holidays
	(holiday-fixed  4 30 "Tenth Day of Ridvan"))
    (if all-bahai-calendar-holidays
	(holiday-fixed  5  1 "Eleventh Day of Ridvan"))
    (holiday-fixed  5  2 "Twelfth Day of Ridvan")
    (holiday-fixed  5 23 "Declaration of the Bab")
    (holiday-fixed  5 29 "Ascension of Baha'u'llah")
    (holiday-fixed  7  9 "Martyrdom of the Bab")
    (holiday-fixed 10 20 "Birth of the Bab")
    (holiday-fixed 11 12 "Birth of Baha'u'llah")
    (if all-bahai-calendar-holidays
	(holiday-fixed 11 26 "Day of the Covenant"))
    (if all-bahai-calendar-holidays
	(holiday-fixed 11 28 "Ascension of `Abdu'l-Baha")))
  "Baha'i holidays.
See the documentation for `calendar-holidays' for details."
  :type 'sexp
  :group 'holidays)

;;;###autoload
(put 'solar-holidays 'risky-local-variable t)
;;;###autoload
(defcustom solar-holidays
  '((if (fboundp 'atan)
	(solar-equinoxes-solstices))
    (if (progn
	  (require 'cal-dst)
	  t)
      (funcall
       'holiday-sexp
        calendar-daylight-savings-starts
        '(format "Daylight Savings Time Begins %s"
                  (if (fboundp 'atan)
                      (solar-time-string
                       (/ calendar-daylight-savings-starts-time (float 60))
                       calendar-standard-time-zone-name)
                    ""))))
    (funcall
     'holiday-sexp
     calendar-daylight-savings-ends
     '(format "Daylight Savings Time Ends %s"
              (if (fboundp 'atan)
                  (solar-time-string
                   (/ calendar-daylight-savings-ends-time (float 60))
                   calendar-daylight-time-zone-name)
                ""))))
  "Sun-related holidays.
See the documentation for `calendar-holidays' for details."
  :type 'sexp
  :group 'holidays)

;;;###autoload
(put 'calendar-holidays 'risky-local-variable t)
(defcustom calendar-holidays
  (append general-holidays local-holidays other-holidays
          christian-holidays hebrew-holidays islamic-holidays
          bahai-holidays oriental-holidays solar-holidays)
  "List of notable days for the command \\[holidays].

Additional holidays are easy to add to the list, just put them in the
list `other-holidays' in your .emacs file.  Similarly, by setting any
of `general-holidays', `local-holidays' `christian-holidays',
`hebrew-holidays', `islamic-holidays', `bahai-holidays',
`oriental-holidays', or `solar-holidays' to nil in your .emacs file,
you can eliminate unwanted categories of holidays.

The aforementioned variables control the holiday choices offered
by the function `list-holidays' when it is called interactively.

They also initialize the default value of `calendar-holidays',
which is the default list of holidays used by the function
`list-holidays' in the non-interactive case.  Note that these
variables have no effect on `calendar-holidays' after it has been
set (e.g. after the calendar is loaded).  In that case, customize
`calendar-holidays' directly.

The intention is that (in the US) `local-holidays' be set in
site-init.el and `other-holidays' be set by the user.

Entries on the list are expressions that return (possibly empty) lists of
items of the form ((month day year) string) of a holiday in the in the
three-month period centered around `displayed-month' of `displayed-year'.
Several basic functions are provided for this purpose:

    (holiday-fixed MONTH DAY STRING) is a fixed date on the Gregorian calendar
    (holiday-float MONTH DAYNAME K STRING &optional day) is the Kth DAYNAME in
                               MONTH on the Gregorian calendar (0 for Sunday,
                               etc.); K<0 means count back from the end of the
                               month.  An optional parameter DAY means the Kth
                               DAYNAME after/before MONTH DAY.
    (holiday-hebrew MONTH DAY STRING)  a fixed date on the Hebrew calendar
    (holiday-islamic MONTH DAY STRING) a fixed date on the Islamic calendar
    (holiday-bahai MONTH DAY STRING)   a fixed date on the Baha'i calendar
    (holiday-julian MONTH DAY STRING)  a fixed date on the Julian calendar
    (holiday-sexp SEXP STRING) SEXP is a Gregorian-date-valued expression
                               in the variable `year'; if it evaluates to
                               a visible date, that's the holiday; if it
                               evaluates to nil, there's no holiday.  STRING
                               is an expression in the variable `date'.

For example, to add Bastille Day, celebrated in France on July 14, add

     (holiday-fixed 7 14 \"Bastille Day\")

to the list.  To add Hurricane Supplication Day, celebrated in the Virgin
Islands on the fourth Monday in August, add

     (holiday-float 8 1 4 \"Hurricane Supplication Day\")

to the list (the last Monday would be specified with `-1' instead of `4').
To add the last day of Hanukkah to the list, use

     (holiday-hebrew 10 2 \"Last day of Hanukkah\")

since the Hebrew months are numbered with 1 starting from Nisan, while to
add the Islamic feast celebrating Mohammed's birthday use

     (holiday-islamic 3 12 \"Mohammed's Birthday\")

since the Islamic months are numbered from 1 starting with Muharram.  To
add an entry for the Baha'i festival of Ridvan, use

     (holiday-bahai 2 13 \"Festival of Ridvan\")

since the Baha'i months are numbered from 1 starting with Baha.  To
add Thomas Jefferson's birthday, April 2, 1743 (Julian), use

     (holiday-julian 4 2 \"Jefferson's Birthday\")

To include a holiday conditionally, use the sexp form or a conditional.  For
example, to include American presidential elections, which occur on the first
Tuesday after the first Monday in November of years divisible by 4, add

     (holiday-sexp
       '(if (zerop (% year 4))
           (calendar-gregorian-from-absolute
             (1+ (calendar-dayname-on-or-before
                   1 (+ 6 (calendar-absolute-from-gregorian
                            (list 11 1 year)))))))
       \"US Presidential Election\")

or

     (if (zerop (% displayed-year 4))
         (holiday-fixed 11
                (extract-calendar-day
                 (calendar-gregorian-from-absolute
                  (1+ (calendar-dayname-on-or-before
                       1 (+ 6 (calendar-absolute-from-gregorian
                               (list 11 1 displayed-year)))))))
                \"US Presidential Election\"))

to the list.  To include the phases of the moon, add

     (lunar-phases)

to the holiday list, where `lunar-phases' is an Emacs-Lisp function that
you've written to return a (possibly empty) list of the relevant VISIBLE dates
with descriptive strings such as

     (((2 6 1989) \"New Moon\") ((2 12 1989) \"First Quarter Moon\") ... )."
  :type 'sexp
  :group 'holidays)

(defconst holiday-buffer "*Holidays*"
  "Name of the buffer used for the displaying the holidays.")

(defconst fancy-diary-buffer "*Fancy Diary Entries*"
  "Name of the buffer used for the optional fancy display of the diary.")

(defconst other-calendars-buffer "*Other Calendars*"
  "Name of the buffer used for the display of date on other calendars.")

(defconst lunar-phases-buffer "*Phases of Moon*"
  "Name of the buffer used for the lunar phases.")

(defmacro increment-calendar-month (mon yr n)
  "Increment the variables MON and YR by N months.
Forward if N is positive or backward if N is negative.
A negative YR is interpreted as BC; -1 being 1 BC, and so on."
  `(let (macro-y)
     (if (< ,yr 0) (setq ,yr (1+ ,yr))) ; -1 BC -> 0 AD, etc
     (setq macro-y (+ (* ,yr 12) ,mon -1 ,n)
           ,mon (1+ (mod macro-y 12))
           ,yr (/ macro-y 12))
     (and (< macro-y 0) (> ,mon 1) (setq ,yr (1- ,yr)))
     (if (< ,yr 1) (setq ,yr (1- ,yr))))) ; 0 AD -> -1 BC, etc

(defun calendar-increment-month (n &optional mon yr)
  "Return the Nth month after MON/YR.
The return value is a pair (MONTH . YEAR).
MON defaults to `displayed-month'.  YR defaults to `displayed-year'."
  (unless mon (setq mon displayed-month))
  (unless yr (setq yr displayed-year))
  (increment-calendar-month mon yr n)
  (cons mon yr))

(defmacro calendar-for-loop (var from init to final do &rest body)
  "Execute a for loop."
  (declare (debug (symbolp "from" form "to" form "do" body)))
  `(let ((,var (1- ,init)))
    (while (>= ,final (setq ,var (1+ ,var)))
      ,@body)))

(defmacro calendar-sum (index initial condition expression)
  "For INDEX = INITIAL et seq, as long as CONDITION holds, sum EXPRESSION."
  (declare (debug (symbolp form form form)))
  `(let ((,index ,initial)
         (sum 0))
    (while ,condition
      (setq sum (+ sum ,expression))
      (setq ,index (1+ ,index)))
    sum))

;; The following are in-line for speed; they can be called thousands of times
;; when looking up holidays or processing the diary.  Here, for example, are
;; the numbers of calls to calendar/diary/holiday functions in preparing the
;; fancy diary display, for a moderately complex diary file, with functions
;; used instead of macros.  There were a total of 10000 such calls:
;;
;;  1934   extract-calendar-month
;;  1852   extract-calendar-year
;;  1819   extract-calendar-day
;;   845   calendar-leap-year-p
;;   837   calendar-day-number
;;   775   calendar-absolute-from-gregorian
;;   346   calendar-last-day-of-month
;;   286   hebrew-calendar-last-day-of-month
;;   188   hebrew-calendar-leap-year-p
;;   180   hebrew-calendar-elapsed-days
;;   163   hebrew-calendar-last-month-of-year
;;    66   calendar-date-compare
;;    65   hebrew-calendar-days-in-year
;;    60   calendar-absolute-from-julian
;;    50   calendar-absolute-from-hebrew
;;    43   calendar-date-equal
;;    38   calendar-gregorian-from-absolute
;;     .
;;     .
;;     .
;;
;; The use of these seven macros eliminates the overhead of 92% of the function
;; calls; it's faster this way.

(defsubst extract-calendar-month (date)
  "Extract the month part of DATE which has the form (month day year)."
  (car date))

;; Note gives wrong answer for result of (calendar-read-date 'noday).
(defsubst extract-calendar-day (date)
  "Extract the day part of DATE which has the form (month day year)."
  (car (cdr date)))

(defsubst extract-calendar-year (date)
  "Extract the year part of DATE which has the form (month day year)."
  (car (cdr (cdr date))))

(defsubst calendar-leap-year-p (year)
  "Return t if YEAR is a Gregorian leap year.
A negative year is interpreted as BC; -1 being 1 BC, and so on."
  ;; 1 BC = 0 AD, 2 BC acts like 1 AD, etc.
  (if (< year 0) (setq year (1- (abs year))))
  (and (zerop (% year 4))
       (or (not (zerop (% year 100)))
           (zerop (% year 400)))))

;; The foregoing is a bit faster, but not as clear as the following:
;;
;;(defsubst calendar-leap-year-p (year)
;;  "Returns t if YEAR is a Gregorian leap year."
;;  (or
;;    (and (=  (% year   4) 0)
;;         (/= (% year 100) 0))
;;    (= (% year 400) 0)))

(defsubst calendar-last-day-of-month (month year)
  "The last day in MONTH during YEAR."
  (if (and (= month 2) (calendar-leap-year-p year))
      29
    (aref [31 28 31 30 31 30 31 31 30 31 30 31] (1- month))))

;; An explanation of the calculation can be found in PascAlgorithms by
;; Edward and Ruth Reingold, Scott-Foresman/Little, Brown, 1988.

(defsubst calendar-day-number (date)
  "Return the day number within the year of the date DATE.
For example, (calendar-day-number '(1 1 1987)) returns the value 1,
while (calendar-day-number '(12 31 1980)) returns 366."
    (let* ((month (extract-calendar-month date))
           (day (extract-calendar-day date))
           (year (extract-calendar-year date))
         (day-of-year (+ day (* 31 (1- month)))))
      (if (> month 2)
          (progn
            (setq day-of-year (- day-of-year (/ (+ 23 (* 4 month)) 10)))
            (if (calendar-leap-year-p year)
                (setq day-of-year (1+ day-of-year)))))
      day-of-year))

(defsubst calendar-absolute-from-gregorian (date)
  "The number of days elapsed between the Gregorian date 12/31/1 BC and DATE.
The Gregorian date Sunday, December 31, 1 BC is imaginary.
DATE is a list of the form (month day year).  A negative year is
interpreted as BC; -1 being 1 BC, and so on.  Dates before 12/31/1 BC
return negative results."
  (let ((year (extract-calendar-year date))
        offset-years)
    (cond ((= year 0)
           (error "There was no year zero"))
          ((> year 0)
           (setq offset-years (1- year))
           (+ (calendar-day-number date) ; Days this year
              (* 365 offset-years)       ; + Days in prior years
              (/ offset-years 4)         ; + Julian leap years
              (- (/ offset-years 100))   ; - century years
              (/ offset-years 400)))     ; + Gregorian leap years
          (t
           ;; Years between date and 1 BC, excluding 1 BC (1 for 2 BC, etc).
           (setq offset-years (abs (1+ year)))
           (- (calendar-day-number date)
              (* 365 offset-years)
              (/ offset-years 4)
              (- (/ offset-years 100))
              (/ offset-years 400)
              (calendar-day-number '(12 31 -1))))))) ; days in year 1 BC

(autoload 'calendar-goto-today "cal-move"
  "Reposition the calendar window so the current date is visible."
  t)

(autoload 'calendar-forward-month "cal-move"
  "Move the cursor forward ARG months."
  t)

(autoload 'calendar-forward-year "cal-move"
  "Move the cursor forward by ARG years."
  t)

(autoload 'calendar-backward-month "cal-move"
  "Move the cursor backward by ARG months."
  t)

(autoload 'calendar-backward-year "cal-move"
  "Move the cursor backward ARG years."
  t)

(autoload 'scroll-calendar-left "cal-move"
  "Scroll the displayed calendar left by ARG months."
  t)

(autoload 'scroll-calendar-right "cal-move"
  "Scroll the displayed calendar window right by ARG months."
  t)

(autoload 'scroll-calendar-left-three-months "cal-move"
  "Scroll the displayed calendar window left by 3*ARG months."
  t)

(autoload 'scroll-calendar-right-three-months "cal-move"
  "Scroll the displayed calendar window right by 3*ARG months."
  t)

(autoload 'calendar-cursor-to-nearest-date "cal-move"
  "Move the cursor to the closest date."
  t)

(autoload 'calendar-forward-day "cal-move"
  "Move the cursor forward ARG days."
  t)

(autoload 'calendar-backward-day "cal-move"
  "Move the cursor back ARG days."
  t)

(autoload 'calendar-forward-week "cal-move"
  "Move the cursor forward ARG weeks."
  t)

(autoload 'calendar-backward-week "cal-move"
  "Move the cursor back ARG weeks."
  t)

(autoload 'calendar-beginning-of-week "cal-move"
  "Move the cursor back ARG calendar-week-start-day's."
  t)

(autoload 'calendar-end-of-week "cal-move"
  "Move the cursor forward ARG calendar-week-start-day+6's."
  t)

(autoload 'calendar-beginning-of-month "cal-move"
  "Move the cursor backward ARG month beginnings."
  t)

(autoload 'calendar-end-of-month "cal-move"
  "Move the cursor forward ARG month ends."
  t)

(autoload 'calendar-beginning-of-year "cal-move"
  "Move the cursor backward ARG year beginnings."
  t)

(autoload 'calendar-end-of-year "cal-move"
  "Move the cursor forward ARG year beginnings."
  t)

(autoload 'calendar-cursor-to-visible-date "cal-move"
  "Move the cursor to DATE that is on the screen."
  t)

(autoload 'calendar-goto-date "cal-move"
  "Move cursor to DATE."
  t)

(autoload 'calendar-goto-day-of-year "cal-move"
  "Move cursor to day of year."
  t)

(autoload 'calendar-only-one-frame-setup "cal-x"
 "Start calendar and display it in a dedicated frame.")

(autoload 'calendar-one-frame-setup "cal-x"
  "Start calendar and display it in a dedicated frame together with the diary.")

(autoload 'calendar-two-frame-setup "cal-x"
  "Start calendar and diary in separate, dedicated frames.")

;;;###autoload
(defcustom calendar-setup nil
  "The frame setup of the calendar.
The choices are: `one-frame' (calendar and diary together in one separate,
dedicated frame); `two-frames' (calendar and diary in separate, dedicated
frames); `calendar-only' (calendar in a separate, dedicated frame); with
any other value the current frame is used.  Using any of the first
three options overrides the value of `view-diary-entries-initially'."
  :type '(choice
          (const :tag "calendar and diary in separate frame" one-frame)
          (const :tag "calendar and diary each in own frame" two-frames)
          (const :tag "calendar in separate frame" calendar-only)
          (const :tag "use current frame" nil))
  :group 'calendar)

(defcustom calendar-minimum-window-height 8
  "Minimum height `generate-calendar-window' should use for calendar window."
  :type 'integer
  :version "22.1"
  :group 'calendar)

;;;###autoload
(defun calendar (&optional arg)
  "Choose between the one frame, two frame, or basic calendar displays.
If called with an optional prefix argument, prompts for month and year.

The original function `calendar' has been renamed `calendar-basic-setup'.
See the documentation of that function for more information."
  (interactive "P")
  (cond ((equal calendar-setup 'one-frame) (calendar-one-frame-setup arg))
        ((equal calendar-setup 'two-frames) (calendar-two-frame-setup arg))
        ((equal calendar-setup 'calendar-only)
         (calendar-only-one-frame-setup arg))
        (t (calendar-basic-setup arg))))

(autoload 'diary-view-entries "diary-lib"
  "Prepare and display a buffer with diary entries.
Searches your diary file for entries that match ARG days starting with
the date indicated by the cursor position in the displayed three-month
calendar."
  t)

(autoload 'list-calendar-holidays "holidays"
  "Create a buffer containing the holidays for the current calendar window.
The holidays are those in the list `calendar-notable-days'.  Returns t if any
holidays are found, nil if not."
  t)

(defun calendar-basic-setup (&optional arg)
  "Display a three-month calendar in another window.
The three months appear side by side, with the current month in the middle
surrounded by the previous and next months.  The cursor is put on today's date.

If called with an optional prefix argument, prompts for month and year.

This function is suitable for execution in a .emacs file; appropriate setting
of the variable `view-diary-entries-initially' will cause the diary entries for
the current date to be displayed in another window.  The value of the variable
`number-of-diary-entries' controls the number of days of diary entries
displayed upon initial display of the calendar.

Once in the calendar window, future or past months can be moved into view.
Arbitrary months can be displayed, or the calendar can be scrolled forward
or backward.

The cursor can be moved forward or backward by one day, one week, one month,
or one year.  All of these commands take prefix arguments which, when negative,
cause movement in the opposite direction.  For convenience, the digit keys
and the minus sign are automatically prefixes.  The window is replotted as
necessary to display the desired date.

Diary entries can be marked on the calendar or displayed in another window.

Use \\[describe-mode] for details of the key bindings in the calendar window.

The Gregorian calendar is assumed.

After loading the calendar, the hooks given by the variable
`calendar-load-hook' are run.  This is the place to add key bindings to the
calendar-mode-map.

After preparing the calendar window initially, the hooks given by the variable
`initial-calendar-window-hook' are run.

The hooks given by the variable `today-visible-calendar-hook' are run
every time the calendar window gets scrolled, if the current date is visible
in the window.  If it is not visible, the hooks given by the variable
`today-invisible-calendar-hook' are run.  Thus, for example, setting
`today-visible-calendar-hook' to 'calendar-star-date will cause today's date
to be replaced by asterisks to highlight it whenever it is in the window."
  (interactive "P")
  (set-buffer (get-buffer-create calendar-buffer))
  (calendar-mode)
  (let* ((pop-up-windows t)
         (split-height-threshold 1000)
         (date (if arg
                   (calendar-read-date t)
                 (calendar-current-date)))
         (month (extract-calendar-month date))
         (year (extract-calendar-year date)))
    ;; (calendar-read-date t) returns a date with day = nil, which is
    ;; not a legal date for the visible test in the diary section.
    (if arg (setcar (cdr date) 1))
    (pop-to-buffer calendar-buffer)
    (increment-calendar-month month year (- calendar-offset))
    (generate-calendar-window month year)
    (if (and view-diary-entries-initially (calendar-date-is-visible-p date))
        (diary-view-entries)))
  (let* ((diary-buffer (get-file-buffer diary-file))
         (diary-window (if diary-buffer (get-buffer-window diary-buffer)))
         (split-height-threshold (if diary-window 2 1000)))
    (if view-calendar-holidays-initially
        (list-calendar-holidays)))
  (run-hooks 'initial-calendar-window-hook))

(autoload 'view-other-diary-entries "diary-lib"
  "Prepare and display buffer of diary entries from an alternative diary file.
Searches for entries that match ARG days, starting with the date indicated
by the cursor position in the displayed three-month calendar.
D-FILE specifies the file to use as the diary file."
  t)

(autoload 'calendar-sunrise-sunset "solar"
  "Local time of sunrise and sunset for date under cursor."
  t)

(autoload 'calendar-phases-of-moon "lunar"
  "Create a buffer of the phases of the moon for the current calendar window."
  t)

(autoload 'calendar-print-french-date "cal-french"
  "Show the French Revolutionary calendar equivalent of the date under the cursor."
  t)

(autoload 'calendar-goto-french-date "cal-french"
 "Move cursor to French Revolutionary date."
  t)

(autoload 'calendar-french-date-string "cal-french"
  "String of French Revolutionary date of Gregorian date.")

(autoload 'calendar-mayan-date-string "cal-mayan"
  "String of Mayan date of Gregorian date.")

(autoload 'calendar-print-mayan-date "cal-mayan"
  "Show the Mayan long count, Tzolkin, and Haab equivalents of the date under the cursor."
  t)

(autoload 'calendar-goto-mayan-long-count-date "cal-mayan"
 "Move cursor to Mayan long count date."
  t)

(autoload 'calendar-next-haab-date "cal-mayan"
  "Move cursor to next instance of Mayan Haab date."
  t)

(autoload 'calendar-previous-haab-date "cal-mayan"
  "Move cursor to previous instance of Mayan Haab date."
  t)

(autoload 'calendar-next-tzolkin-date "cal-mayan"
  "Move cursor to next instance of Mayan Tzolkin date."
  t)

(autoload 'calendar-previous-tzolkin-date "cal-mayan"
  "Move cursor to previous instance of Mayan Tzolkin date."
  t)

(autoload 'calendar-next-calendar-round-date "cal-mayan"
  "Move cursor to next instance of Mayan Haab/Tzolkin combination."
  t)

(autoload 'calendar-previous-calendar-round-date "cal-mayan"
  "Move cursor to previous instance of Mayan Haab/Tzolkin combination."
  t)

(autoload 'calendar-goto-chinese-date "cal-china"
   "Move cursor to Chinese date."
   t)

(autoload 'calendar-print-chinese-date "cal-china"
 "Show the Chinese date equivalents of date."
 t)

(autoload 'calendar-chinese-date-string "cal-china"
  "String of Chinese date of Gregorian date.")

(autoload 'calendar-absolute-from-astro  "cal-julian"
  "Absolute date of astronomical (Julian) day number D."
  t )

(autoload 'calendar-astro-from-absolute "cal-julian"
  "Astronomical (Julian) day number of absolute date D.")

(autoload 'calendar-astro-date-string "cal-julian"
  "String of astronomical (Julian) day number of Gregorian date.")

(autoload 'calendar-goto-astro-day-number "cal-julian"
   "Move cursor to astronomical (Julian) day number."
   t)

(autoload 'calendar-print-astro-day-number "cal-julian"
   "Show the astro date equivalents of date."
   t)

(autoload 'calendar-julian-from-absolute "cal-julian"
  "Compute the Julian (month day year) corresponding to the absolute DATE.
The absolute date is the number of days elapsed since the (imaginary)
Gregorian date Sunday, December 31, 1 BC.")

(autoload 'calendar-goto-julian-date "cal-julian"
  "Move cursor to Julian DATE; echo Julian date unless NOECHO is t."
  t)

(autoload 'calendar-print-julian-date "cal-julian"
  "Show the Julian calendar equivalent of the date under the cursor."
  t)

(autoload 'calendar-julian-date-string "cal-julian"
  "String of Julian date of Gregorian DATE.
Defaults to today's date if DATE is not given.
Driven by the variable `calendar-date-display-form'.")

(autoload 'calendar-goto-iso-date "cal-iso"
  "Move cursor to ISO date."
  t)

(autoload 'calendar-goto-iso-week "cal-iso"
  "Move cursor to start of ISO week."
  t)

(autoload 'calendar-print-iso-date "cal-iso"
  "Show the ISO date equivalents of date."
  t)

(autoload 'calendar-iso-date-string "cal-iso"
  "String of ISO date of Gregorian date.")

(autoload 'calendar-goto-islamic-date "cal-islam"
  "Move cursor to Islamic date."
  t)

(autoload 'calendar-print-islamic-date "cal-islam"
  "Show the Islamic date equivalents of date."
  t)

(autoload 'calendar-islamic-date-string "cal-islam"
  "String of Islamic date of Gregorian date.")

(autoload 'calendar-print-bahai-date "cal-bahai"
  "Show the Baha'i date equivalents of date."
  t)

(autoload 'calendar-bahai-date-string "cal-bahai"
  "String of Baha'i date of Gregorian date.")

(autoload 'calendar-goto-hebrew-date "cal-hebrew"
  "Move cursor to Hebrew date."
  t)

(autoload 'calendar-print-hebrew-date "cal-hebrew"
  "Show the Hebrew date equivalents of date."
  t)

(autoload 'calendar-hebrew-date-string "cal-hebrew"
  "String of Hebrew date of Gregorian date.")

(autoload 'calendar-goto-coptic-date "cal-coptic"
   "Move cursor to Coptic date."
   t)

(autoload 'calendar-print-coptic-date "cal-coptic"
 "Show the Coptic date equivalents of date."
 t)

(autoload 'calendar-coptic-date-string "cal-coptic"
  "String of Coptic date of Gregorian date.")

(autoload 'calendar-goto-ethiopic-date "cal-coptic"
   "Move cursor to Ethiopic date."
   t)

(autoload 'calendar-print-ethiopic-date "cal-coptic"
 "Show the Ethiopic date equivalents of date."
 t)

(autoload 'calendar-ethiopic-date-string "cal-coptic"
  "String of Ethiopic date of Gregorian date.")

(autoload 'calendar-goto-persian-date "cal-persia"
   "Move cursor to Persian date."
   t)

(autoload 'calendar-print-persian-date "cal-persia"
 "Show the Persian date equivalents of date."
 t)

(autoload 'calendar-persian-date-string "cal-persia"
  "String of Persian date of Gregorian date.")

(autoload 'diary-show-all-entries "diary-lib"
  "Show all of the diary entries in the diary file.
This function gets rid of the selective display of the diary file so that
all entries, not just some, are visible.  If there is no diary buffer, one
is created."
  t)

(autoload 'mark-diary-entries "diary-lib"
  "Mark days in the calendar window that have diary entries.
Each entry in diary file visible in the calendar window is marked."
  t)

(autoload 'make-diary-entry "diary-lib"
  "Insert a diary entry STRING which may be NONMARKING in FILE.")

(autoload 'insert-diary-entry "diary-lib"
  "Insert a diary entry for the date indicated by point."
  t)

(autoload 'insert-weekly-diary-entry "diary-lib"
  "Insert a weekly diary entry for the day of the week indicated by point."
  t)


(autoload 'insert-monthly-diary-entry "diary-lib"
  "Insert a monthly diary entry for the day of the month indicated by point."
  t)

(autoload 'insert-yearly-diary-entry "diary-lib"
  "Insert an annual diary entry for the day of the year indicated by point."
  t)

(autoload 'insert-anniversary-diary-entry "diary-lib"
  "Insert an anniversary diary entry for the date indicated by point."
  t)

(autoload 'insert-block-diary-entry "diary-lib"
  "Insert a block diary entry for the dates indicated by point and mark."
  t)

(autoload 'insert-cyclic-diary-entry "diary-lib"
  "Insert a cyclic diary entry starting at the date indicated by point."
  t)

(autoload 'insert-hebrew-diary-entry "cal-hebrew"
  "Insert a diary entry for the Hebrew date corresponding to the date
indicated by point."
  t)

(autoload 'insert-monthly-hebrew-diary-entry "cal-hebrew"
  "Insert a monthly diary entry for the day of the Hebrew month corresponding
to the date indicated by point."
  t)

(autoload 'insert-yearly-hebrew-diary-entry "cal-hebrew"
  "Insert an annual diary entry for the day of the Hebrew year corresponding
to the date indicated by point."
  t)

(autoload 'insert-islamic-diary-entry "cal-islam"
  "Insert a diary entry for the Islamic date corresponding to the date
indicated by point."
  t)

(autoload 'insert-monthly-islamic-diary-entry "cal-islam"
  "Insert a monthly diary entry for the day of the Islamic month corresponding
to the date indicated by point."
  t)

(autoload 'insert-yearly-islamic-diary-entry "cal-islam"
  "Insert an annual diary entry for the day of the Islamic year corresponding
to the date indicated by point."
  t)

(autoload 'insert-bahai-diary-entry "cal-bahai"
  "Insert a diary entry for the Baha'i date corresponding to the date
indicated by point."
  t)

(autoload 'insert-monthly-bahai-diary-entry "cal-bahai"
  "Insert a monthly diary entry for the day of the Baha'i month corresponding
to the date indicated by point."
  t)

(autoload 'insert-yearly-bahai-diary-entry "cal-bahai"
  "Insert an annual diary entry for the day of the Baha'i year corresponding
to the date indicated by point."
  t)

(autoload 'cal-tex-cursor-month "cal-tex"
  "Make a buffer with LaTeX commands for the month cursor is on.
Optional prefix argument specifies number of months to be produced.
Calendar is condensed onto one page." t)

(autoload 'cal-tex-cursor-month-landscape "cal-tex"
  "Make a buffer with LaTeX commands for the month cursor is on.
Optional prefix argument specifies number of months to be produced." t)

(autoload 'cal-tex-cursor-day "cal-tex"
  "Make a buffer with LaTeX commands for the day cursor is on." t)

(autoload 'cal-tex-cursor-week "cal-tex"
  "Make a buffer with LaTeX commands for a two-page one-week calendar.
It applies to the week that point is in.
Optional prefix argument specifies number of weeks.
Holidays are included if `cal-tex-holidays' is t." t)

(autoload 'cal-tex-cursor-week2 "cal-tex"
  "Make a buffer with LaTeX commands for a two-page one-week calendar.
It applies to the week that point is in.
Optional prefix argument specifies number of weeks.
Holidays are included if `cal-tex-holidays' is t." t)

(autoload 'cal-tex-cursor-week-iso "cal-tex"
  "Make a buffer with LaTeX commands for a one page ISO-style weekly calendar.
Optional prefix argument specifies number of weeks.
Diary entries are included if `cal-tex-diary' is t.
Holidays are included if `cal-tex-holidays' is t." t)

(autoload 'cal-tex-cursor-week-monday "cal-tex"
  "Make a buffer with LaTeX commands for a two-page one-week calendar.
It applies to the week that point is in, and starts on Monday.
Optional prefix argument specifies number of weeks.
Holidays are included if `cal-tex-holidays' is t." t)

(autoload 'cal-tex-cursor-filofax-2week "cal-tex"
  "Two-weeks-at-a-glance Filofax style calendar for week indicated by cursor.
Optional prefix argument specifies number of weeks.
Diary entries are included if cal-tex-diary is t.
Holidays are included if `cal-tex-holidays' is t." t)

(autoload 'cal-tex-cursor-filofax-week "cal-tex"
  "One-week-at-a-glance Filofax style calendar for week indicated by cursor.
Optional prefix argument specifies number of weeks.
Weeks start on Monday.
Diary entries are included if cal-tex-diary is t.
Holidays are included if `cal-tex-holidays' is t." t)

(autoload 'cal-tex-cursor-filofax-daily "cal-tex"
  "Day-per-page Filofax style calendar for week indicated by cursor.
Optional prefix argument specifies number of weeks.  Weeks start on Monday.
Diary entries are included if `cal-tex-diary' is t.
Holidays are included if `cal-tex-holidays' is t." t)

(autoload 'cal-tex-cursor-year "cal-tex"
  "Make a buffer with LaTeX commands for a year's calendar.
Optional prefix argument specifies number of years." t)

(autoload 'cal-tex-cursor-year-landscape "cal-tex"
  "Make a buffer with LaTeX commands for a year's calendar (landscape).
Optional prefix argument specifies number of years." t)

(autoload 'cal-tex-cursor-filofax-year "cal-tex"
  "Make a buffer with LaTeX commands for a year's calendar (Filofax).
Optional prefix argument specifies number of years." t)

(autoload 'cal-html-cursor-month "cal-html"
  "Write an HTML calendar file for numeric MONTH of four-digit YEAR.
The output directory DIR is created if necessary.  Interactively,
MONTH and YEAR are taken from the calendar cursor position.  Note
that any existing output files are overwritten." t)

(autoload 'cal-html-cursor-year "cal-html"
  "Write HTML calendar files (index and monthly pages) for four-digit YEAR.
The output directory DIR is created if necessary.  Interactively,
YEAR is taken from the calendar cursor position.  Note that any
existing output files are overwritten." t)

(autoload 'mark-calendar-holidays "holidays"
  "Mark notable days in the calendar window."
  t)

(autoload 'calendar-cursor-holidays "holidays"
  "Find holidays for the date specified by the cursor in the calendar window."
  t)

(defun generate-calendar-window (&optional mon yr)
  "Generate the calendar window for the current date.
Or, for optional MON, YR."
  (let* ((buffer-read-only nil)
         (today (calendar-current-date))
         (month (extract-calendar-month today))
         (day (extract-calendar-day today))
         (year (extract-calendar-year today))
         (today-visible
          (or (not mon)
              (let ((offset (calendar-interval mon yr month year)))
                (and (<= offset 1) (>= offset -1)))))
         (day-in-week (calendar-day-of-week today))
         (in-calendar-window (eq (window-buffer (selected-window))
                                 (get-buffer calendar-buffer))))
    (update-calendar-mode-line)
    (if mon
        (generate-calendar mon yr)
      (generate-calendar month year))
    (calendar-cursor-to-visible-date
     (if today-visible today (list displayed-month 1 displayed-year)))
    (set-buffer-modified-p nil)
    ;; Don't do any window-related stuff if we weren't called from a
    ;; window displaying the calendar
    (when in-calendar-window
      (if (or (one-window-p t) (/= (frame-width) (window-width)))
          ;; Don't mess with the window size, but ensure that the first
          ;; line is fully visible
          ;; XEmacs change.  XEmacs doesn't have this function
          (if (fboundp 'set-window-vscroll)
              (set-window-vscroll nil 0))
        ;; Adjust the window to exactly fit the displayed calendar
        ;; XEmacs change, f-w-t-b shows up in 21.5
        (cal-fit-window-to-buffer))
      (sit-for 0))
    (if (and (boundp 'font-lock-mode)
	     font-lock-mode)
	(font-lock-fontify-buffer))
    (and mark-holidays-in-calendar
;;;         (calendar-date-is-legal-p today) ; useful for BC dates
         (mark-calendar-holidays)
         (and in-calendar-window (sit-for 0)))
    (unwind-protect
        (if mark-diary-entries-in-calendar (mark-diary-entries))
      (if today-visible
          (run-hooks 'today-visible-calendar-hook)
        (run-hooks 'today-invisible-calendar-hook)))))

(defun generate-calendar (month year)
  "Generate a three-month Gregorian calendar centered around MONTH, YEAR."
;;; A negative YEAR is interpreted as BC; -1 being 1 BC, and so on.
;;; Note that while calendars for years BC could be displayed as it
;;; stands, almost all other calendar functions (eg holidays) would
;;; at best have unpredictable results for such dates.
  (if (< (+ month (* 12 (1- year))) 2)
      (error "Months before January, 1 AD cannot be displayed"))
  (setq displayed-month month
        displayed-year year)
  (erase-buffer)
  (increment-calendar-month month year -1)
  (calendar-for-loop i from 0 to 2 do
       (generate-calendar-month month year (+ 5 (* 25 i)))
       (increment-calendar-month month year 1)))

(defun generate-calendar-month (month year indent)
  "Produce a calendar for MONTH, YEAR on the Gregorian calendar.
The calendar is inserted at the top of the buffer in which point is currently
located, but indented INDENT spaces.  The indentation is done from the first
character on the line and does not disturb the first INDENT characters on the
line."
  (let* ((blank-days;; at start of month
          (mod
           (- (calendar-day-of-week (list month 1 year))
              calendar-week-start-day)
           7))
	 (last (calendar-last-day-of-month month year)))
   (goto-char (point-min))
   (calendar-insert-indented
    (calendar-string-spread
     ;; XEmacs change - primarily for cal-japanese
     (list (format "%s %s"
		   (calendar-month-name month)
		   (calendar-year-name year month 1))) ?  20)
    indent t)
   (calendar-insert-indented "" indent);; Go to proper spot
   ;; Use the first two characters of each day to head the columns.
   (calendar-for-loop i from 0 to 6 do
      (insert
       (let ((string
              (calendar-day-name (mod (+ calendar-week-start-day i) 7) nil t)))
         (if enable-multibyte-characters
             (truncate-string-to-width string 2)
           (substring string 0 2)))
       " "))
   (calendar-insert-indented "" 0 t);; Force onto following line
   (calendar-insert-indented "" indent);; Go to proper spot
   ;; Add blank days before the first of the month
   (calendar-for-loop i from 1 to blank-days do (insert "   "))
   ;; Put in the days of the month
   (calendar-for-loop i from 1 to last do
      (insert (format "%2d " i))
      (add-text-properties
       ;; XEmacs change.
       ;; This makes the extent the width of the date, 1 vs 2 digits wide.
       (- (point) (if (< i 10) 2 3)) (1- (point))
       '(mouse-face highlight
	 help-echo "mouse-2: menu of operations for this date"))
      (and (zerop (mod (+ i blank-days) 7))
           (/= i last)
           (calendar-insert-indented "" 0 t)    ;; Force onto following line
           (calendar-insert-indented "" indent)))));; Go to proper spot

(defun calendar-insert-indented (string indent &optional newline)
  "Insert STRING at column INDENT.
If the optional parameter NEWLINE is t, leave point at start of next line,
inserting a newline if there was no next line; otherwise, leave point after
the inserted text.  Value is always t."
  ;; Try to move to that column.
  (move-to-column indent)
  ;; If line is too short, indent out to that column.
  (if (< (current-column) indent)
      (indent-to indent))
  (insert string)
  ;; Advance to next line, if requested.
  (if newline
      (progn
	(end-of-line)
	(if (eobp)
            (newline)
	  (forward-line 1))))
  t)

(defun redraw-calendar ()
  "Redraw the calendar display, if `calendar-buffer' is live."
  (interactive)
  (if (get-buffer calendar-buffer)
      (with-current-buffer calendar-buffer
        (let ((cursor-date (calendar-cursor-to-nearest-date)))
          (generate-calendar-window displayed-month displayed-year)
          (calendar-cursor-to-visible-date cursor-date)))))

;;;###autoload
;; XEmacs - for now we are keeping this original definition
;; if I use the newer definition, I get autoload errors about regexp-opt
(defcustom calendar-week-start-day 0
  "The day of the week on which a week in the calendar begins.
0 means Sunday (default), 1 means Monday, and so on.

If you change this variable directly (without using customize)
after starting `calendar', you should call `redraw-calendar' to
update the calendar display to reflect the change, otherwise
movement commands will not work correctly."
  :type 'integer
  :set (lambda (sym val)
         (set sym val)
         (let ((buffer (get-buffer calendar-buffer)))
           (when (buffer-live-p buffer)
             (with-current-buffer buffer
               (redraw-calendar)))))
  :group 'calendar)

(defcustom calendar-debug-sexp nil
  "Turn debugging on when evaluating a sexp in the diary or holiday list."
  :type 'boolean
  :group 'calendar)

(defvar calendar-mode-map nil)
(if calendar-mode-map
    nil
  (let ((map (make-keymap)))
    ;; XEmacs change.  Uncommenting this make xemacs puke.
    ;; (suppress-keymap map)
    (dolist (c '(narrow-to-region mark-word mark-sexp mark-paragraph
                 mark-defun mark-whole-buffer mark-page
                 downcase-region upcase-region kill-region
                 copy-region-as-kill capitalize-region write-region))
      (define-key map (vector 'remap c) 'calendar-not-implemented))
    (define-key map ">"     'scroll-calendar-right)
    (define-key map "\C-x>" 'scroll-calendar-right)
    (define-key map [prior] 'scroll-calendar-right-three-months)
    (define-key map "\ev"   'scroll-calendar-right-three-months)
    (define-key map "<"     'scroll-calendar-left)
    (define-key map "\C-x<" 'scroll-calendar-left)
    (define-key map [next]  'scroll-calendar-left-three-months)
    (define-key map "\C-v"  'scroll-calendar-left-three-months)
    (define-key map "\C-b"  'calendar-backward-day)
    (define-key map "\C-p"  'calendar-backward-week)
    (define-key map "\e{"   'calendar-backward-month)
    (define-key map "\C-x[" 'calendar-backward-year)
    (define-key map "\C-f"  'calendar-forward-day)
    (define-key map "\C-n"  'calendar-forward-week)
    (define-key map [left]  'calendar-backward-day)
    (define-key map [up]    'calendar-backward-week)
    (define-key map [right] 'calendar-forward-day)
    (define-key map [down]  'calendar-forward-week)
    (define-key map "\e}"   'calendar-forward-month)
    (define-key map "\C-x]" 'calendar-forward-year)
    (define-key map "\C-a"  'calendar-beginning-of-week)
    (define-key map "\C-e"  'calendar-end-of-week)
    (define-key map "\ea"   'calendar-beginning-of-month)
    (define-key map "\ee"   'calendar-end-of-month)
    (define-key map "\e<"   'calendar-beginning-of-year)
    (define-key map "\e>"   'calendar-end-of-year)
    (define-key map "\C-@"  'calendar-set-mark)
    ;; Many people are used to typing C-SPC and getting C-@.
    (define-key map [?\C- ] 'calendar-set-mark)
    (define-key map "\C-x\C-x" 'calendar-exchange-point-and-mark)
    (define-key map "\e=" 'calendar-count-days-region)
    (define-key map "gd"  'calendar-goto-date)
    (define-key map "gD"  'calendar-goto-day-of-year)
    (define-key map "gj"  'calendar-goto-julian-date)
    (define-key map "ga"  'calendar-goto-astro-day-number)
    (define-key map "gh"  'calendar-goto-hebrew-date)
    (define-key map "gi"  'calendar-goto-islamic-date)
    (define-key map "gb"  'calendar-goto-bahai-date)
    (define-key map "gC"  'calendar-goto-chinese-date)
    (define-key map "gk"  'calendar-goto-coptic-date)
    (define-key map "ge"  'calendar-goto-ethiopic-date)
    (define-key map "gp"  'calendar-goto-persian-date)
    (define-key map "gc"  'calendar-goto-iso-date)
    (define-key map "gw"  'calendar-goto-iso-week)
    (define-key map "gf"  'calendar-goto-french-date)
    (define-key map "gml"  'calendar-goto-mayan-long-count-date)
    (define-key map "gmpc" 'calendar-previous-calendar-round-date)
    (define-key map "gmnc" 'calendar-next-calendar-round-date)
    (define-key map "gmph" 'calendar-previous-haab-date)
    (define-key map "gmnh" 'calendar-next-haab-date)
    (define-key map "gmpt" 'calendar-previous-tzolkin-date)
    (define-key map "gmnt" 'calendar-next-tzolkin-date)
    (define-key map "Aa"   'appt-add)
    (define-key map "Ad"   'appt-delete)
    (define-key map "S"   'calendar-sunrise-sunset)
    (define-key map "M"   'calendar-phases-of-moon)
    (define-key map " "   'scroll-other-window)
    (define-key map (kbd "DEL") 'scroll-other-window-down)
    (define-key map [backspace] 'scroll-other-window-down)
    (define-key map "\C-c\C-l" 'redraw-calendar)
    (define-key map "."   'calendar-goto-today)
    (define-key map "o"   'calendar-other-month)
    (define-key map "q"   'exit-calendar)
    (define-key map "a"   'list-calendar-holidays)
    (define-key map "h"   'calendar-cursor-holidays)
    (define-key map "x"   'mark-calendar-holidays)
    (define-key map "u"   'calendar-unmark)
    (define-key map "m"   'mark-diary-entries)
    (define-key map "d"   'diary-view-entries)
    (define-key map "D"   'view-other-diary-entries)
    (define-key map "s"   'diary-show-all-entries)
    (define-key map "pd"  'calendar-print-day-of-year)
    (define-key map "pC"  'calendar-print-chinese-date)
    (define-key map "pk"  'calendar-print-coptic-date)
    (define-key map "pe"  'calendar-print-ethiopic-date)
    (define-key map "pp"  'calendar-print-persian-date)
    (define-key map "pc"  'calendar-print-iso-date)
    (define-key map "pj"  'calendar-print-julian-date)
    (define-key map "pa"  'calendar-print-astro-day-number)
    (define-key map "ph"  'calendar-print-hebrew-date)
    (define-key map "pi"  'calendar-print-islamic-date)
    (define-key map "pb"  'calendar-print-bahai-date)
    (define-key map "pf"  'calendar-print-french-date)
    (define-key map "pm"  'calendar-print-mayan-date)
    (define-key map "po"  'calendar-print-other-dates)
    (define-key map "id"  'insert-diary-entry)
    (define-key map "iw"  'insert-weekly-diary-entry)
    (define-key map "im"  'insert-monthly-diary-entry)
    (define-key map "iy"  'insert-yearly-diary-entry)
    (define-key map "ia"  'insert-anniversary-diary-entry)
    (define-key map "ib"  'insert-block-diary-entry)
    (define-key map "ic"  'insert-cyclic-diary-entry)
    (define-key map "ihd" 'insert-hebrew-diary-entry)
    (define-key map "ihm" 'insert-monthly-hebrew-diary-entry)
    (define-key map "ihy" 'insert-yearly-hebrew-diary-entry)
    (define-key map "iid" 'insert-islamic-diary-entry)
    (define-key map "iim" 'insert-monthly-islamic-diary-entry)
    (define-key map "iiy" 'insert-yearly-islamic-diary-entry)
    (define-key map "iBd" 'insert-bahai-diary-entry)
    (define-key map "iBm" 'insert-monthly-bahai-diary-entry)
    (define-key map "iBy" 'insert-yearly-bahai-diary-entry)
    (define-key map "?"   'calendar-goto-info-node)
    (define-key map "Hm" 'cal-html-cursor-month)
    (define-key map "Hy" 'cal-html-cursor-year)
    (define-key map "tm" 'cal-tex-cursor-month)
    (define-key map "tM" 'cal-tex-cursor-month-landscape)
    (define-key map "td" 'cal-tex-cursor-day)
    (define-key map "tw1" 'cal-tex-cursor-week)
    (define-key map "tw2" 'cal-tex-cursor-week2)
    (define-key map "tw3" 'cal-tex-cursor-week-iso)
    (define-key map "tw4" 'cal-tex-cursor-week-monday)
    (define-key map "tfd" 'cal-tex-cursor-filofax-daily)
    (define-key map "tfw" 'cal-tex-cursor-filofax-2week)
    (define-key map "tfW" 'cal-tex-cursor-filofax-week)
    (define-key map "tfy" 'cal-tex-cursor-filofax-year)
    (define-key map "ty" 'cal-tex-cursor-year)
    (define-key map "tY" 'cal-tex-cursor-year-landscape)
    (setq calendar-mode-map map)
    (require 'cal-xemacs)))

(defun describe-calendar-mode ()
  "Create a help buffer with a brief description of the `calendar-mode'."
  (interactive)
  ;; XEmacs - we don't have this
  ;; (help-setup-xref (list #'describe-calendar-mode) (interactive-p))
  (with-output-to-temp-buffer (help-buffer)
    (princ
     (format
      "Calendar Mode:\nFor a complete description, type %s\n%s\n"
      (substitute-command-keys
       "\\<calendar-mode-map>\\[describe-mode] from within the calendar")
      (substitute-command-keys "\\{calendar-mode-map}")))
    (save-excursion
      (set-buffer standard-output)
      (help-mode))
    (print-help-return-message)))

;; Calendar mode is suitable only for specially formatted data.
(put 'calendar-mode 'mode-class 'special)

(defvar calendar-mode-line-format
  (list
   (propertize (substitute-command-keys
		"\\<calendar-mode-map>\\[scroll-calendar-left]")
	       'help-echo "mouse-2: scroll left"
               'mouse-face 'modeline-mousable
	       'keymap (cal-make-mode-line-mouse-map 'button2
						 'mouse-scroll-calendar-left))
   "Calendar"
   (concat
    (propertize
     (substitute-command-keys
      "\\<calendar-mode-map>\\[calendar-goto-info-node] info")
     'help-echo "mouse-2: read Info on Calendar"
     'mouse-face 'modeline-mousable
     'keymap (cal-make-mode-line-mouse-map 'button2 'calendar-goto-info-node))
    "/"
    (propertize
     (substitute-command-keys
     "\\<calendar-mode-map>\\[calendar-other-month] other")
     'help-echo "mouse-2: choose another month"
     'mouse-face 'modeline-mousable
     'keymap (cal-make-mode-line-mouse-map
	      'button2 'mouse-calendar-other-month))
    "/"
    (propertize
     (substitute-command-keys
     "\\<calendar-mode-map>\\[calendar-goto-today] today")
     'help-echo "mouse-2: go to today's date"
     'mouse-face 'modeline-mousable
     'keymap (cal-make-mode-line-mouse-map 'button2 #'calendar-goto-today)))
   '(calendar-date-string (calendar-current-date) t)
   (propertize (substitute-command-keys
		"\\<calendar-mode-map>\\[scroll-calendar-right]")
               'help-echo "mouse-2: scroll right"
               'mouse-face 'modeline-mousable
               'keymap (cal-make-mode-line-mouse-map
                        'button2 'mouse-scroll-calendar-right)))
  "The mode line of the calendar buffer.

This must be a list of items that evaluate to strings--those strings are
evaluated and concatenated together, evenly separated by blanks.  The variable
`date' is available for use as the date under (or near) the cursor; `date'
defaults to the current date if it is otherwise undefined.  Here is an example
value that has the Hebrew date, the day number/days remaining in the year,
and the ISO week/year numbers in the mode.  When calendar-move-hook is set to
'update-calendar-mode-line, these mode line shows these values for the date
under the cursor:

      (list
       \"\"
       '(calendar-hebrew-date-string date)
       '(let* ((year (extract-calendar-year date))
               (d (calendar-day-number date))
               (days-remaining
                (- (calendar-day-number (list 12 31 year)) d)))
          (format \"%d/%d\" d days-remaining))
       '(let* ((d (calendar-absolute-from-gregorian date))
               (iso-date (calendar-iso-from-absolute d)))
          (format \"ISO week %d of %d\"
            (extract-calendar-month iso-date)
            (extract-calendar-year iso-date)))
       \"\"))
")

(defun mouse-scroll-calendar-left (event)
  "Scroll the displayed calendar left by one month.
Maintains the relative position of the cursor
with respect to the calendar as well as possible."
  (interactive "e")
  (save-selected-window
    ;; XEmacs change
    (select-window (event-window event))
    (scroll-calendar-left 1)))

(defun mouse-scroll-calendar-right (event)
  "Scroll the displayed calendar right by one month.
Maintains the relative position of the cursor
with respect to the calendar as well as possible."
  (interactive "e")
  (save-selected-window
    ;; XEmacs change
    (select-window (event-window event))
    (scroll-calendar-right 1)))

(defun mouse-calendar-other-month (event)
  "Display a three-month calendar centered around a specified month and year."
  (interactive "e")
  (save-selected-window
    ;; XEmacs change
    (select-window (event-window event))
    (call-interactively 'calendar-other-month)))

(defun calendar-goto-info-node ()
  "Go to the info node for the calendar."
  (interactive)
  (require 'info)
  (let ((where (save-window-excursion
		 (Info-find-emacs-command-nodes 'calendar))))
    (if (not where)
        (error "Couldn't find documentation for the calendar")
      (let (same-window-buffer-names)
	(info))
      (Info-find-node (car (car where)) (car (cdr (car where)))))))



(defun calendar-mode ()
  "A major mode for the calendar window.

For a complete description, type \
\\<calendar-mode-map>\\[calendar-goto-info-node] from within the calendar.

\\<calendar-mode-map>\\{calendar-mode-map}"
  (kill-all-local-variables)
  (setq major-mode 'calendar-mode)
  (setq mode-name "Calendar")
  (use-local-map calendar-mode-map)
  (setq buffer-read-only t)
  (setq indent-tabs-mode nil)
  (update-calendar-mode-line)
  (if (and (featurep 'xemacs)
	   (featurep 'menubar) current-menubar)
      (progn
	(require 'cal-xemacs)
	(calendar-add-menus)
	(make-variable-buffer-local 'scroll-on-clipped-lines)
	(setq scroll-on-clipped-lines nil)))
  (add-hook 'activate-menubar-hook 'cal-menu-update nil t)
  (make-local-variable 'calendar-mark-ring)
  (make-local-variable 'displayed-month);;  Month in middle of window.
  (make-local-variable 'displayed-year)	;;  Year in middle of window.
  (set (make-local-variable 'font-lock-defaults)
       '(calendar-font-lock-keywords t))
  (run-mode-hooks 'calendar-mode-hook))

(defun calendar-string-spread (strings char length)
  "Concatenate list of STRINGS separated with copies of CHAR to fill LENGTH.
The effect is like mapconcat but the separating pieces are as balanced as
possible.  Each item of STRINGS is evaluated before concatenation so it can
actually be an expression that evaluates to a string.  If LENGTH is too short,
the STRINGS are just concatenated and the result truncated."
;; The algorithm is based on equation (3.25) on page 85 of Concrete
;; Mathematics by Ronald L. Graham, Donald E. Knuth, and Oren Patashnik,
;; Addison-Wesley, Reading, MA, 1989
  (let* ((strings (mapcar 'eval
                          (if (< (length strings) 2)
                              (append (list "") strings (list ""))
                            strings)))
	 ;; XEmacs change.  Mule vs non-Mule
 	 (func (if (fboundp 'string-width) 'string-width 'length))
	 ;; XEmacs change.  primarily for cal-japanese.
	 (n (- length (funcall func (apply 'concat strings))))
         (m (1- (length strings)))
         (s (car strings))
         (strings (cdr strings))
         (i 0))
    (dolist (string strings)
      (setq s (concat s
                      (make-string (max 0 (/ (+ n i) m)) char)
                      string))
      (setq i (1+ i)))
    ;; XEmacs change - primarily for cal-japanese
    (truncate-string-to-width s length)))

(defun update-calendar-mode-line ()
  "Update the calendar mode line with the current date and date style."
  (if (bufferp (get-buffer calendar-buffer))
      (with-current-buffer calendar-buffer
        (setq mode-line-format
              (cal-tp-ml-conv 
              (calendar-string-spread
               (let ((date (condition-case nil
                               (calendar-cursor-to-nearest-date)
                             (error (calendar-current-date)))))
                 (mapcar 'eval  calendar-mode-line-format))
               ?  (frame-width))))
        (force-mode-line-update))))

(defun calendar-window-list ()
  "List of all calendar-related windows."
  (let ((calendar-buffers (calendar-buffer-list))
        list)
    (walk-windows (lambda (w)
		    (if (memq (window-buffer w) calendar-buffers)
			(push w list)))
                  nil t)
    list))

(defun calendar-buffer-list ()
  "List of all calendar-related buffers."
  (let* ((diary-buffer (get-file-buffer diary-file))
         (buffers (list "*Yahrzeits*" lunar-phases-buffer holiday-buffer
                        fancy-diary-buffer diary-buffer calendar-buffer
                        other-calendars-buffer))
         (buffer-list nil))
    (dolist (b buffers)
      (setq b (cond ((stringp b) (get-buffer b))
                    ((bufferp b) b)
                    (t nil)))
      (if b (push b buffer-list)))
    buffer-list))

(defun exit-calendar ()
  "Get out of the calendar window and hide it and related buffers."
  (interactive)
  (let* ((diary-buffer (get-file-buffer diary-file)))
    (if (or (not diary-buffer)
            (not (buffer-modified-p diary-buffer))
            (yes-or-no-p
             "Diary modified; do you really want to exit the calendar? "))
      ;; Need to do this multiple times because one time can replace some
      ;; calendar-related buffers with other calendar-related buffers
      (mapcar (lambda (x)
                (mapcar 'calendar-hide-window (calendar-window-list)))
              (calendar-window-list)))))

(defun calendar-hide-window (window)
  "Hide WINDOW if it is calendar-related."
  (let ((buffer (if (window-live-p window) (window-buffer window))))
    (if (memq buffer (calendar-buffer-list))
        (cond
         ((and (display-multi-frame-p)
               (eq 'icon (cdr (assoc 'visibility
                                     (frame-parameters
                                      (window-frame window))))))
          nil)
         ((and (display-multi-frame-p) (window-dedicated-p window))
          (if calendar-remove-frame-by-deleting
              (delete-frame (window-frame window))
              (iconify-frame (window-frame window))))
         ((not (and (select-window window) (one-window-p window)))
          (delete-window window))
         (t (set-buffer buffer)
            (bury-buffer))))))

(defun calendar-current-date ()
  "Return the current date in a list (month day year)."
  (let ((now (decode-time)))
    (list (nth 4 now) (nth 3 now) (nth 5 now))))

(defun calendar-cursor-to-date (&optional error)
  "Return a list (month day year) of current cursor position.
If cursor is not on a specific date, signals an error if optional parameter
ERROR is t, otherwise just returns nil."
  ;; #### This check is to avoid a race condition created by
  ;; pop-to-buffer's call to other-window interacting with the 19.13
  ;; changes allowing that to be in another frame.
;  (if (not (number-or-marker-p displayed-month))
;      nil
  (let* ((segment (/ (current-column) 25))
         (month (% (+ displayed-month segment -1) 12))
         (month (if (= 0 month) 12 month))
         (year
          (cond
           ((and (=  12 month) (= segment 0)) (1- displayed-year))
           ((and (=   1 month) (= segment 2)) (1+ displayed-year))
           (t displayed-year))))
    (if (and (looking-at "[ 0-9]?[0-9][^0-9]")
             (< 2 (count-lines (point-min) (point))))
        (save-excursion
          (if (not (looking-at " "))
                   (re-search-backward "[^0-9]"))
          (list month
                (string-to-number (buffer-substring (1+ (point)) (+ 4 (point))))
                year))
      (if (and (looking-at "\\*")
               (save-excursion
                 (re-search-backward "[^*]")
                 (looking-at ".\\*\\*")))
          (list month calendar-starred-day year)
        (if error (error "Not on a date!"))))))
;)

(add-to-list 'debug-ignored-errors "Not on a date!")

;; The following version of calendar-gregorian-from-absolute is preferred for
;; reasons of clarity, BUT it's much slower than the version that follows it.

;;(defun calendar-gregorian-from-absolute (date)
;;  "Compute the list (month day year) corresponding to the absolute DATE.
;;The absolute date is the number of days elapsed since the (imaginary)
;;Gregorian date Sunday, December 31, 1 BC."
;;  (let* ((approx (/ date 366));; Approximation from below.
;;         (year                ;; Search forward from the approximation.
;;          (+ approx
;;             (calendar-sum y approx
;;                 (>= date (calendar-absolute-from-gregorian (list 1 1 (1+ y))))
;;                  1)))
;;         (month         ;; Search forward from January.
;;          (1+ (calendar-sum m 1
;;                   (> date
;;                      (calendar-absolute-from-gregorian
;;                       (list m (calendar-last-day-of-month m year) year)))
;;                   1)))
;;         (day           ;; Calculate the day by subtraction.
;;          (- date
;;             (1- (calendar-absolute-from-gregorian (list month 1 year))))))
;;    (list month day year)))

(defun calendar-gregorian-from-absolute (date)
  "Compute the list (month day year) corresponding to the absolute DATE.
The absolute date is the number of days elapsed since the (imaginary)
Gregorian date Sunday, December 31, 1 BC.  This function does not
handle dates in years BC."
;; See the footnote on page 384 of ``Calendrical Calculations, Part II:
;; Three Historical Calendars'' by E. M. Reingold,  N. Dershowitz, and S. M.
;; Clamen, Software--Practice and Experience, Volume 23, Number 4
;; (April, 1993), pages 383-404 for an explanation.
  (let* ((d0 (1- date))
         (n400 (/ d0 146097))
         (d1 (% d0 146097))
         (n100 (/ d1 36524))
         (d2 (% d1 36524))
         (n4 (/ d2 1461))
         (d3 (% d2 1461))
         (n1 (/ d3 365))
         (day (1+ (% d3 365)))
         (year (+ (* 400 n400) (* 100 n100) (* n4 4) n1)))
    (if (or (= n100 4) (= n1 4))
        (list 12 31 year)
      (let ((year (1+ year))
            (month 1))
        (while (let ((mdays (calendar-last-day-of-month month year)))
                 (and (< mdays day)
                      (setq day (- day mdays))))
          (setq month (1+ month)))
        (list month day year)))))

(defun calendar-other-month (month year)
  "Display a three-month calendar centered around MONTH and YEAR."
  (interactive (calendar-read-date 'noday))
  (if (and (= month displayed-month)
           (= year displayed-year))
      nil
    (let ((old-date (calendar-cursor-to-date))
          (today (calendar-current-date)))
      (generate-calendar-window month year)
      (calendar-cursor-to-visible-date
       (cond
        ((calendar-date-is-visible-p old-date) old-date)
        ((calendar-date-is-visible-p today) today)
        (t (list month 1 year)))))))

(defun calendar-set-mark (arg)
  "Mark the date under the cursor, or jump to marked date.
With no prefix argument, push current date onto marked date ring.
With argument, jump to mark, pop it, and put point at end of ring."
  (interactive "P")
  (let ((date (calendar-cursor-to-date t)))
    (if (null arg)
        (progn
          (push date calendar-mark-ring)
          ;; Since the top of the mark ring is the marked date in the
          ;; calendar, the mark ring in the calendar is one longer than
          ;; in other buffers to get the same effect.
          (if (> (length calendar-mark-ring) (1+ mark-ring-max))
              (setcdr (nthcdr mark-ring-max calendar-mark-ring) nil))
          (message "Mark set"))
      (if (null calendar-mark-ring)
          (error "No mark set in this buffer")
        (calendar-goto-date (car calendar-mark-ring))
        (setq calendar-mark-ring
              (cdr (nconc calendar-mark-ring (list date))))))))

(defun calendar-exchange-point-and-mark ()
  "Exchange the current cursor position with the marked date."
  (interactive)
  (let ((mark (car calendar-mark-ring))
        (date (calendar-cursor-to-date t)))
    (if (null mark)
        (error "No mark set in this buffer")
      (setq calendar-mark-ring (cons date (cdr calendar-mark-ring)))
      (calendar-goto-date mark))))

(defun calendar-count-days-region ()
  "Count the number of days (inclusive) between point and the mark."
  (interactive)
  (let* ((days (- (calendar-absolute-from-gregorian
                   (calendar-cursor-to-date t))
                  (calendar-absolute-from-gregorian
                   (or (car calendar-mark-ring)
                       (error "No mark set in this buffer")))))
         (days (1+ (if (> days 0) days (- days)))))
    (message "Region has %d day%s (inclusive)"
             days (if (> days 1) "s" ""))))

(defun calendar-not-implemented ()
  "Not implemented."
  (interactive)
  (error "%s not available in the calendar"
         (global-key-binding (this-command-keys))))

(defun calendar-read (prompt acceptable &optional initial-contents)
  "Return an object read from the minibuffer.
Prompt with the string PROMPT and use the function ACCEPTABLE to decide if
entered item is acceptable.  If non-nil, optional third arg INITIAL-CONTENTS
is a string to insert in the minibuffer before reading."
  (let ((value (read-minibuffer prompt initial-contents)))
    (while (not (funcall acceptable value))
      (setq value (read-minibuffer prompt initial-contents)))
    value))

(defun calendar-read-date (&optional noday)
  "Prompt for Gregorian date.  Return a list (month day year).
If optional NODAY is t, does not ask for day, but just returns
\(month nil year); if NODAY is any other non-nil value the value returned is
\(month year)"
  (let* ((year (calendar-read
                "Year (>0): "
                (lambda (x) (> x 0))
                (int-to-string (extract-calendar-year
                                (calendar-current-date)))))
         (month-array calendar-month-name-array)
         (completion-ignore-case t)
         ;; XEmacs change, we don't have assoc-string
         (month (cdr (cal-assoc-string
                       (completing-read
                        "Month name: "
                        (mapcar 'list (append month-array nil))
                        nil t)
                      (calendar-make-alist month-array 1) t)))
         (last (calendar-last-day-of-month month year)))
    (if noday
        (if (eq noday t)
            (list month nil year)
          (list month year))
      (list month
            (calendar-read (format "Day (1-%d): " last)
			   (lambda (x) (and (< 0 x) (<= x last))))
            year))))

(defun calendar-interval (mon1 yr1 mon2 yr2)
  "The number of months difference between MON1, YR1 and MON2, YR2.
The result is positive if the second date is later than the first.
Negative years are interpreted as years BC; -1 being 1 BC, and so on."
  (if (< yr1 0) (setq yr1 (1+ yr1)))      ; -1 BC -> 0 AD, etc
  (if (< yr2 0) (setq yr2 (1+ yr2)))
  (+ (* 12 (- yr2 yr1))
     (- mon2 mon1)))

(defvar calendar-abbrev-length 3
  "*Length of abbreviations to be used for day and month names.
See also `calendar-day-abbrev-array' and `calendar-month-abbrev-array'.")

;; XEmacs change for cal-japanese
(defvar calendar-english-day-name-array
  ["Sunday" "Monday" "Tuesday" "Wednesday" "Thursday" "Friday" "Saturday"])

(defvar calendar-day-name-array calendar-english-day-name-array
  "*Array of capitalized strings giving, in order, the day names.
The first two characters of each string will be used to head the
day columns in the calendar.  See also the variable
`calendar-day-abbrev-array'.")

(defvar calendar-day-abbrev-array
  [nil nil nil nil nil nil nil]
  "*Array of capitalized strings giving the abbreviated day names.
The order should be the same as that of the full names specified
in `calendar-day-name-array'.  These abbreviations may be used
instead of the full names in the diary file.  Do not include a
trailing `.' in the strings specified in this variable, though
you may use such in the diary file.  If any element of this array
is nil, then the abbreviation will be constructed as the first
`calendar-abbrev-length' characters of the corresponding full name.")

;; XEmacs change for cal-japanese
(defvar calendar-english-month-name-array
  ["January" "February" "March"     "April"   "May"      "June"
   "July"    "August"   "September" "October" "November" "December"])

(defvar calendar-month-name-array calendar-english-month-name-array
  "*Array of capitalized strings giving, in order, the month names.
See also the variable `calendar-month-abbrev-array'.")

(defvar calendar-month-abbrev-array
  [nil nil nil nil nil nil nil nil nil nil nil nil]
 "*Array of capitalized strings giving the abbreviated month names.
The order should be the same as that of the full names specified
in `calendar-month-name-array'.  These abbreviations are used in
the calendar menu entries, and can also be used in the diary
file.  Do not include a trailing `.' in the strings specified in
this variable, though you may use such in the diary file.  If any
element of this array is nil, then the abbreviation will be
constructed as the first `calendar-abbrev-length' characters of the
corresponding full name.")

(defun calendar-abbrev-construct (abbrev full &optional period)
  "Internal calendar function to return a complete abbreviation array.
ABBREV is an array of abbreviations, FULL the corresponding array
of full names.  The return value is the ABBREV array, with any nil
elements replaced by the first three characters taken from the
corresponding element of FULL.  If optional argument PERIOD is non-nil,
each element returned has a final `.' character."
  (let (elem array name)
    (dotimes (i (length full))
      (setq name (aref full i)
            elem (or (aref abbrev i)
                     (substring name 0
                                (min calendar-abbrev-length (length name))))
            elem (format "%s%s" elem (if period "." ""))
            array (append array (list elem))))
    (vconcat array)))

(defvar calendar-font-lock-keywords
  `((,(concat (regexp-opt (mapcar 'identity calendar-month-name-array) t)
	      " -?[0-9]+")
     . font-lock-function-name-face) ; month and year
    (,(regexp-opt
       (list (substring (aref calendar-day-name-array 6) 0 2)
	     (substring (aref calendar-day-name-array 0) 0 2)))
     ;; Saturdays and Sundays are hilited differently.
     . font-lock-comment-face)
    ;; First two chars of each day are used in the calendar.
    (,(regexp-opt (mapcar (lambda (x) (substring x 0 2)) calendar-day-name-array))
     . font-lock-reference-face))
  "Default keywords to highlight in Calendar mode.")

(defun calendar-day-name (date &optional abbrev absolute)
  "Return a string with the name of the day of the week of DATE.
DATE should be a list in the format (MONTH DAY YEAR), unless the
optional argument ABSOLUTE is non-nil, in which case DATE should
be an integer in the range 0 to 6 corresponding to the day of the
week.  Day names are taken from the variable `calendar-day-name-array',
unless the optional argument ABBREV is non-nil, in which case
the variable `calendar-day-abbrev-array' is used."
  (aref (if abbrev
            (calendar-abbrev-construct calendar-day-abbrev-array
                                       calendar-day-name-array)
          calendar-day-name-array)
        (if absolute date (calendar-day-of-week date))))

(defun calendar-make-alist (sequence &optional start-index filter abbrevs)
  "Make an assoc list corresponding to SEQUENCE.
Each element of sequence will be associated with an integer, starting
from 1, or from START-INDEX if that is non-nil.  If a sequence ABBREVS
is supplied, the function `calendar-abbrev-construct' is used to
construct abbreviations corresponding to the elements in SEQUENCE.
Each abbreviation is entered into the alist with the same
association index as the full name it represents.
If FILTER is provided, apply it to each key in the alist."
  (let ((index 0)
        (offset (or start-index 1))
        (aseq (if abbrevs (calendar-abbrev-construct abbrevs sequence)))
        (aseqp (if abbrevs (calendar-abbrev-construct abbrevs sequence
                                                      'period)))
        alist elem)
    (dotimes (i (length sequence) (reverse alist))
      (setq index (+ i offset)
            elem (elt sequence i)
            alist
            (cons (cons (if filter (funcall filter elem) elem) index) alist))
      (if aseq
          (setq elem (elt aseq i)
                alist (cons (cons (if filter (funcall filter elem) elem)
                                  index) alist)))
      (if aseqp
          (setq elem (elt aseqp i)
                alist (cons (cons (if filter (funcall filter elem) elem)
                                  index) alist))))))
;(defun calendar-month-name (month &optional width)
;  "The name of MONTH.
;If WIDTH is non-nil, return just the first WIDTH characters of the name."
;  (let ((string (aref calendar-month-name-array (1- month))))
;    (if width
;       (let ((i 0) (result "") (pos 0))
;	 ;; XEmacs change - primarily for cal-japanese.
;         (while (and (< i width) (< i (length string)))
;           (let ((chartext (char-to-string (aref string pos))))
;             (setq pos (+ pos (length chartext)))
;             (setq result (concat result chartext)))
;           (setq i (1+ i)))
;         result)
;      string)))

(defun calendar-month-name (month &optional abbrev)
  "Return a string with the name of month number MONTH.
Months are numbered from one.  Month names are taken from the
variable `calendar-month-name-array', unless the optional
argument ABBREV is non-nil, in which case
`calendar-month-abbrev-array' is used."
  (aref (if abbrev
            (calendar-abbrev-construct calendar-month-abbrev-array
                                       calendar-month-name-array)
          calendar-month-name-array)
        (1- month)))

;; XEmacs only
(defun calendar-english-year-name (year month day)
  (format "%d" year))
(defvar calendar-year-name-function 'calendar-english-year-name)

;; XEmacs only
(defun calendar-year-name (year month day)
  (funcall calendar-year-name-function year month day))

(defun calendar-day-of-week (date)
  "Return the day-of-the-week index of DATE, 0 for Sunday, 1 for Monday, etc.
DATE is a list of the form (month day year).  A negative year is
interpreted as BC; -1 being 1 BC, and so on."
  (mod (calendar-absolute-from-gregorian date) 7))

(defun calendar-unmark ()
  "Delete all diary/holiday marks/highlighting from the calendar."
  (interactive)
  (setq mark-holidays-in-calendar nil)
  (setq mark-diary-entries-in-calendar nil)
  (redraw-calendar))

(defun calendar-date-is-visible-p (date)
  "Return t if DATE is valid and is visible in the calendar window."
  (let ((gap (calendar-interval
              displayed-month displayed-year
              (extract-calendar-month date) (extract-calendar-year date))))
    (and (calendar-date-is-legal-p date) (> 2 gap) (< -2 gap))))

(defun calendar-date-is-legal-p (date)
  "Return t if DATE is a valid date."
  (let ((month (extract-calendar-month date))
        (day (extract-calendar-day date))
        (year (extract-calendar-year date)))
    (and (<= 1 month) (<= month 12)
         ;; (calendar-read-date t) returns a date with day = nil.
         ;; Should not be valid (?), since many funcs prob assume integer.
         ;; (calendar-read-date 'noday) returns (month year), which
         ;; currently results in extract-calendar-year returning nil.
         day year (<= 1 day) (<= day (calendar-last-day-of-month month year))
         ;; BC dates left as non-valid, to suppress errors from
         ;; complex holiday algorithms not suitable for years BC.
         ;; Note there are side effects on calendar navigation.
         (<= 1 year))))

(defun calendar-date-equal (date1 date2)
  "Return t if the DATE1 and DATE2 are the same."
  (and
   (= (extract-calendar-month date1) (extract-calendar-month date2))
   (= (extract-calendar-day date1) (extract-calendar-day date2))
   (= (extract-calendar-year date1) (extract-calendar-year date2))))

(defun mark-visible-calendar-date (date &optional mark)
  "Mark DATE in the calendar window with MARK.
MARK is a single-character string, a list of face attributes/values, or a face.
MARK defaults to `diary-entry-marker'."
  (if (calendar-date-is-legal-p date)
      (with-current-buffer calendar-buffer
        (save-excursion
          (calendar-cursor-to-visible-date date)
          (setq mark
                (or (and (stringp mark) (= (length mark) 1) mark) ; single-char
                    (and (listp mark) (> (length mark) 0) mark)   ; attr list
                    ;; XEmacs change, our facep != Emacs facep
                    (and (facep (find-face mark)) mark)           ; face-name
                    diary-entry-marker))
          (cond
           ;; face or an attr-list that contained a face
           ;; XEmacs change, our facep != Emacs facep
           ((and (symbolp mark)
                 (facep (find-face mark)))
            ;; XEmacs change, we use extents, not overlays
            (set-extent-property 
             (make-extent (1- (point)) (1+ (point))) 'face mark))
           ;; single-char
           ((and (stringp mark) (= (length mark) 1))
            (let ((inhibit-read-only t))
              (forward-char 1)
              ;; Insert before delete so as to better preserve markers.
              (insert mark)
              (delete-char 1)
              (forward-char -2)))
           (t ;; attr list
            (let ((temp-face
                   (make-symbol
                    (apply 'concat "temp-"
                           (mapcar (lambda (sym)
                                     (cond
                                      ((symbolp sym) (symbol-name sym))
                                      ((numberp sym) (number-to-string sym))
                                      (t sym)))
                                   mark))))
                  (faceinfo mark))
              (make-face temp-face)
              ;; Remove :face info from the mark, copy the face info into
              ;; temp-face
              (while (setq faceinfo (memq :face faceinfo))
                (copy-face (read (nth 1 faceinfo)) temp-face)
                (setcar faceinfo nil)
                (setcar (cdr faceinfo) nil))
              (setq mark (delq nil mark))
              ;; Apply the font aspects
              ;; XEmacs change. Emacs has set-face-attribute
              ;; face-custom-attributes-set is equivalent
              (apply 'face-custom-attributes-set temp-face nil nil mark)
              ;; XEmacs change, we use extents, not overlays
              (set-extent-property
               (make-extent (1- (point)) (1+ (point))) 'face temp-face))))))))

(defun calendar-star-date ()
  "Replace the date under the cursor in the calendar window with asterisks.
This function can be used with the `today-visible-calendar-hook' run after the
calendar window has been prepared."
  (let ((inhibit-read-only t)
        (modified (buffer-modified-p)))
    (forward-char 1)
    (set (make-local-variable 'calendar-starred-day)
         (string-to-number
          (buffer-substring (point) (- (point) 2))))
    ;; Insert before deleting, to better preserve markers.
    (insert "**")
    (forward-char -2)
    (delete-char -2)
    (forward-char 1)
    (restore-buffer-modified-p modified)))

(defun calendar-mark-today ()
  "Mark the date under the cursor in the calendar window.
The date is marked with `calendar-today-marker'.  This function can be used with
the `today-visible-calendar-hook' run after the calendar window has been
prepared."
  (mark-visible-calendar-date
   (calendar-cursor-to-date)
   calendar-today-marker))

(defun calendar-date-compare (date1 date2)
  "Return t if DATE1 is before DATE2, nil otherwise.
The actual dates are in the car of DATE1 and DATE2."
  (< (calendar-absolute-from-gregorian (car date1))
     (calendar-absolute-from-gregorian (car date2))))

(defun calendar-date-string (date &optional abbreviate nodayname)
  "A string form of DATE, driven by the variable `calendar-date-display-form'.
An optional parameter ABBREVIATE, when non-nil, causes the month
and day names to be abbreviated as specified by
`calendar-month-abbrev-array' and `calendar-day-abbrev-array',
respectively.  An optional parameter NODAYNAME, when t, omits the
name of the day of the week."
  (let* ((dayname
          (unless nodayname
            (calendar-day-name date abbreviate)))
         (month (extract-calendar-month date))
         (monthname (calendar-month-name month abbreviate))
         (day (int-to-string (extract-calendar-day date)))
         (month (int-to-string month))
         (year (int-to-string (extract-calendar-year date))))
    (mapconcat 'eval calendar-date-display-form "")))

(defun calendar-dayname-on-or-before (dayname date)
  "Return the absolute date of the DAYNAME on or before absolute DATE.
DAYNAME=0 means Sunday, DAYNAME=1 means Monday, and so on.

Note: Applying this function to d+6 gives us the DAYNAME on or after an
absolute day d.  Similarly, applying it to d+3 gives the DAYNAME nearest to
absolute date d, applying it to d-1 gives the DAYNAME previous to absolute
date d, and applying it to d+7 gives the DAYNAME following absolute date d."
  (- date (% (- date dayname) 7)))

(defun calendar-nth-named-absday (n dayname month year &optional day)
  "The absolute date of Nth DAYNAME in MONTH, YEAR before/after optional DAY.
A DAYNAME of 0 means Sunday, 1 means Monday, and so on.  If N<0,
return the Nth DAYNAME before MONTH DAY, YEAR (inclusive).
If N>0, return the Nth DAYNAME after MONTH DAY, YEAR (inclusive).

If DAY is omitted, it defaults to 1 if N>0, and MONTH's last day otherwise."
  (if (> n 0)
      (+ (* 7 (1- n))
	 (calendar-dayname-on-or-before
	  dayname
	  (+ 6 (calendar-absolute-from-gregorian
		(list month (or day 1) year)))))
    (+ (* 7 (1+ n))
       (calendar-dayname-on-or-before
	dayname
	(calendar-absolute-from-gregorian
	 (list month
	       (or day (calendar-last-day-of-month month year))
	       year))))))

(defun calendar-nth-named-day (n dayname month year &optional day)
  "The date of Nth DAYNAME in MONTH, YEAR before/after optional DAY.
A DAYNAME of 0 means Sunday, 1 means Monday, and so on.  If N<0,
return the Nth DAYNAME before MONTH DAY, YEAR (inclusive).
If N>0, return the Nth DAYNAME after MONTH DAY, YEAR (inclusive).

If DAY is omitted, it defaults to 1 if N>0, and MONTH's last day otherwise."
  (calendar-gregorian-from-absolute
   (calendar-nth-named-absday n dayname month year day)))

(defun calendar-day-of-year-string (&optional date)
  "String of day number of year of Gregorian DATE.
Defaults to today's date if DATE is not given."
  (let* ((d (or date (calendar-current-date)))
         (year (extract-calendar-year d))
         (day (calendar-day-number d))
         (days-remaining (- (calendar-day-number (list 12 31 year)) day)))
    (format "Day %d of %d; %d day%s remaining in the year"
            day year days-remaining (if (= days-remaining 1) "" "s"))))

(defun calendar-print-other-dates ()
  "Show dates on other calendars for date under the cursor."
  (interactive)
  (let* ((date (calendar-cursor-to-date t)))
    (with-current-buffer (get-buffer-create other-calendars-buffer)
      (let ((inhibit-read-only t)
            (modified (buffer-modified-p)))
        (calendar-set-mode-line
         (concat (calendar-date-string date) " (Gregorian)"))
        (erase-buffer)
        (apply
         'insert
         (delq nil
               (list
                (calendar-day-of-year-string date) "\n"
                (format "ISO date: %s\n" (calendar-iso-date-string date))
                (format "Julian date: %s\n"
                        (calendar-julian-date-string date))
                (format "Astronomical (Julian) day number (at noon UTC): %s.0\n"
                        (calendar-astro-date-string date))
                (format "Fixed (RD) date: %s\n"
                        (calendar-absolute-from-gregorian date))
                (format "Hebrew date (before sunset): %s\n"
                        (calendar-hebrew-date-string date))
                (format "Persian date: %s\n"
                        (calendar-persian-date-string date))
                (let ((i (calendar-islamic-date-string date)))
                  (if (not (string-equal i ""))
                      (format "Islamic date (before sunset): %s\n" i)))
                (let ((b (calendar-bahai-date-string date)))
                  (if (not (string-equal b ""))
                      (format "Baha'i date (before sunset): %s\n" b)))
                (format "Chinese date: %s\n"
                        (calendar-chinese-date-string date))
                (let ((c (calendar-coptic-date-string date)))
                  (if (not (string-equal c ""))
                      (format "Coptic date: %s\n" c)))
                (let ((e (calendar-ethiopic-date-string date)))
                  (if (not (string-equal e ""))
                      (format "Ethiopic date: %s\n" e)))
                (let ((f (calendar-french-date-string date)))
                  (if (not (string-equal f ""))
                      (format "French Revolutionary date: %s\n" f)))
                (format "Mayan date: %s\n"
                        (calendar-mayan-date-string date)))))
        (goto-char (point-min))
        ;; XEmacs change, we don't have restore-buffer-modified-p
        (set-buffer-modified-p nil)
        (setq buffer-read-only t))
      (display-buffer other-calendars-buffer))))

(defun calendar-print-day-of-year ()
  "Show day number in year/days remaining in year for date under the cursor."
  (interactive)
  (message (calendar-day-of-year-string (calendar-cursor-to-date t))))

(defun calendar-set-mode-line (str)
  "Set mode line to STR, centered, surrounded by dashes."
  (let* ((edges (window-pixel-edges))
         ;; Emacs:
         ;; As per doc of window-width, total visible mode-line length.
         ;; (width (- (nth 2 edges) (nth 0 edges))))

         ;; XEmacs change, Emacs is calculating the full column width of the 
         ;; window.
         ;; window-pixel-edges doesn't give the right info, but 
         ;; window-full-width does
         ;; 
         (width (window-full-width)))
    (setq mode-line-format
          (if buffer-file-name
              `("-" mode-line-modified
                ,(calendar-string-spread (list str) ?- (- width 6))
                "---")
            (calendar-string-spread (list str) ?- width)))))

(defun calendar-mod (m n)
  "Non-negative remainder of M/N with N instead of 0."
  (1+ (mod (1- m) n)))

(run-hooks 'calendar-load-hook)

(provide 'calendar)

;; Local variables:
;; byte-compile-dynamic: t
;; End:

;; arch-tag: 19c61596-c8fb-4c69-bcf1-7dd739919cd8
;;; calendar.el ends here