1 ;;; holidays.el --- holiday functions for the calendar package
3 ;;; Copyright (C) 1989, 1990, 1992, 1993, 1994 Free Software Foundation, Inc.
5 ;; Author: Edward M. Reingold <reingold@cs.uiuc.edu>
6 ;; Keywords: holidays, calendar
8 ;; This file is part of GNU Emacs.
10 ;; GNU Emacs is free software; you can redistribute it and/or modify
11 ;; it under the terms of the GNU General Public License as published by
12 ;; the Free Software Foundation; either version 2, or (at your option)
15 ;; GNU Emacs is distributed in the hope that it will be useful,
16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 ;; GNU General Public License for more details.
20 ;; You should have received a copy of the GNU General Public License
21 ;; along with GNU Emacs; see the file COPYING. If not, write to
22 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
26 ;; This collection of functions implements the holiday features as described
29 ;; Comments, corrections, and improvements should be sent to
30 ;; Edward M. Reingold Department of Computer Science
31 ;; (217) 333-6733 University of Illinois at Urbana-Champaign
32 ;; reingold@cs.uiuc.edu 1304 West Springfield Avenue
33 ;; Urbana, Illinois 61801
35 ;; Technical details of all the calendrical calculations can be found in
36 ;; ``Calendrical Calculations'' by Nachum Dershowitz and Edward M. Reingold,
37 ;; Software--Practice and Experience, Volume 20, Number 9 (September, 1990),
38 ;; pages 899-928. ``Calendrical Calculations, Part II: Three Historical
39 ;; Calendars'' by E. M. Reingold, N. Dershowitz, and S. M. Clamen,
40 ;; Software--Practice and Experience, Volume 23, Number 4 (April, 1993),
43 ;; Hard copies of these two papers can be obtained by sending email to
44 ;; reingold@cs.uiuc.edu with the SUBJECT "send-paper-cal" (no quotes) and
45 ;; the message BODY containing your mailing address (snail).
51 (autoload 'solar-equinoxes-solstices
"solar"
52 "Date and time of equinoxes and solstices, if visible in the calendar window.
53 Requires floating point."
56 (defun holidays (&optional arg
)
57 "Display the holidays for last month, this month, and next month.
58 If called with an optional prefix argument, prompts for month and year.
60 This function is suitable for execution in a .emacs file."
63 (let* ((completion-ignore-case t
)
65 (calendar-read-date t
)
66 (calendar-current-date)))
67 (displayed-month (extract-calendar-month date
))
68 (displayed-year (extract-calendar-year date
)))
69 (list-calendar-holidays))))
71 (defun check-calendar-holidays (date)
72 "Check the list of holidays for any that occur on DATE.
73 The value returned is a list of strings of relevant holiday descriptions.
74 The holidays are those in the list calendar-holidays."
75 (let* ((displayed-month (extract-calendar-month date
))
76 (displayed-year (extract-calendar-year date
))
77 (h (calendar-holiday-list))
80 (if (calendar-date-equal date
(car (car h
)))
81 (setq holiday-list
(append holiday-list
(cdr (car h
)))))
85 (defun calendar-cursor-holidays ()
86 "Find holidays for the date specified by the cursor in the calendar window."
88 (message "Checking holidays...")
89 (let* ((date (calendar-cursor-to-date t
))
90 (date-string (calendar-date-string date
))
91 (holiday-list (check-calendar-holidays date
))
92 (holiday-string (mapconcat 'identity holiday-list
"; "))
93 (msg (format "%s: %s" date-string holiday-string
)))
94 (if (not holiday-list
)
95 (message "No holidays known for %s" date-string
)
96 (if (<= (length msg
) (frame-width))
98 (set-buffer (get-buffer-create holiday-buffer
))
99 (setq buffer-read-only nil
)
100 (calendar-set-mode-line date-string
)
102 (insert (mapconcat 'identity holiday-list
"\n"))
103 (goto-char (point-min))
104 (set-buffer-modified-p nil
)
105 (setq buffer-read-only t
)
106 (display-buffer holiday-buffer
)
107 (message "Checking holidays...done")))))
109 (defun mark-calendar-holidays ()
110 "Mark notable days in the calendar window."
112 (setq mark-holidays-in-calendar t
)
113 (message "Marking holidays...")
114 (let ((holiday-list (calendar-holiday-list)))
116 (mark-visible-calendar-date
117 (car (car holiday-list
)) calendar-holiday-marker
)
118 (setq holiday-list
(cdr holiday-list
))))
119 (message "Marking holidays...done"))
121 (defun list-calendar-holidays ()
122 "Create a buffer containing the holidays for the current calendar window.
123 The holidays are those in the list calendar-notable-days. Returns t if any
124 holidays are found, nil if not."
126 (message "Looking up holidays...")
127 (let ((holiday-list (calendar-holiday-list))
132 (if (not holiday-list
)
134 (message "Looking up holidays...none found")
136 (set-buffer (get-buffer-create holiday-buffer
))
137 (setq buffer-read-only nil
)
138 (increment-calendar-month m1 y1 -
1)
139 (increment-calendar-month m2 y2
1)
140 (calendar-set-mode-line
142 (format "Notable Dates from %s to %s, %d%%-"
143 (calendar-month-name m1
) (calendar-month-name m2
) y2
)
144 (format "Notable Dates from %s, %d to %s, %d%%-"
145 (calendar-month-name m1
) y1
(calendar-month-name m2
) y2
)))
149 '(lambda (x) (concat (calendar-date-string (car x
))
152 (goto-char (point-min))
153 (set-buffer-modified-p nil
)
154 (setq buffer-read-only t
)
155 (display-buffer holiday-buffer
)
156 (message "Looking up holidays...done")
159 (defun calendar-holiday-list ()
160 "Form the list of holidays that occur on dates in the calendar window.
161 The holidays are those in the list calendar-holidays."
162 (let ((p calendar-holidays
)
166 (if calendar-debug-sexp
167 (let ((stack-trace-on-error t
))
172 (message "Bad holiday list item: %s" (car p
))
175 (setq holiday-list
(append holidays holiday-list
))))
177 (setq holiday-list
(sort holiday-list
'calendar-date-compare
))))
179 ;; Below are the functions that calculate the dates of holidays; these
180 ;; are eval'ed in the function calendar-holiday-list. If you
181 ;; write other such functions, be sure to imitate the style used below.
182 ;; Remember that each function must return a list of items of the form
183 ;; ((month day year) string) of VISIBLE dates in the calendar window.
185 (defun holiday-fixed (month day string
)
186 "Holiday on MONTH, DAY (Gregorian) called STRING.
187 If MONTH, DAY is visible, the value returned is the list (((MONTH DAY year)
188 STRING)). Returns nil if it is not visible in the current calendar window."
189 (let ((m displayed-month
)
191 (increment-calendar-month m y
(- 11 month
))
193 (list (list (list month day y
) string
)))))
195 (defun holiday-float (month dayname n string
&optional day
)
196 "Holiday on MONTH, DAYNAME (Nth occurrence, Gregorian) called STRING.
197 If the Nth DAYNAME in MONTH is visible, the value returned is the list
198 \(((MONTH DAY year) STRING)).
200 If N<0, count backward from the end of MONTH.
202 An optional parameter DAY means the Nth DAYNAME after/before MONTH DAY.
204 Returns nil if it is not visible in the current calendar window."
205 (let ((m displayed-month
)
207 (increment-calendar-month m y
(- 11 month
))
209 (list (list (calendar-nth-named-day n dayname month y day
) string
)))))
211 (defun holiday-julian (month day string
)
212 "Holiday on MONTH, DAY (Julian) called STRING.
213 If MONTH, DAY (Julian) is visible, the value returned is corresponding
214 Gregorian date in the form of the list (((month day year) STRING)). Returns
215 nil if it is not visible in the current calendar window."
216 (let ((m1 displayed-month
)
221 (increment-calendar-month m1 y1 -
1)
222 (increment-calendar-month m2 y2
1)
223 (let* ((start-date (calendar-absolute-from-gregorian
225 (end-date (calendar-absolute-from-gregorian
226 (list m2
(calendar-last-day-of-month m2 y2
) y2
)))
227 (julian-start (calendar-julian-from-absolute start-date
))
228 (julian-end (calendar-julian-from-absolute end-date
))
229 (julian-y1 (extract-calendar-year julian-start
))
230 (julian-y2 (extract-calendar-year julian-end
)))
231 (setq year
(if (< 10 month
) julian-y1 julian-y2
))
232 (let ((date (calendar-gregorian-from-absolute
233 (calendar-absolute-from-julian
234 (list month day year
)))))
235 (if (calendar-date-is-visible-p date
)
236 (list (list date string
)))))))
238 (defun holiday-islamic (month day string
)
239 "Holiday on MONTH, DAY (Islamic) called STRING.
240 If MONTH, DAY (Islamic) is visible, the value returned is corresponding
241 Gregorian date in the form of the list (((month day year) STRING)). Returns
242 nil if it is not visible in the current calendar window."
243 (let* ((islamic-date (calendar-islamic-from-absolute
244 (calendar-absolute-from-gregorian
245 (list displayed-month
15 displayed-year
))))
246 (m (extract-calendar-month islamic-date
))
247 (y (extract-calendar-year islamic-date
))
250 nil
;; Islamic calendar doesn't apply.
251 (increment-calendar-month m y
(- 10 month
))
252 (if (> m
7);; Islamic date might be visible
253 (let ((date (calendar-gregorian-from-absolute
254 (calendar-absolute-from-islamic (list month day y
)))))
255 (if (calendar-date-is-visible-p date
)
256 (list (list date string
))))))))
258 (defun holiday-hebrew (month day string
)
259 "Holiday on MONTH, DAY (Hebrew) called STRING.
260 If MONTH, DAY (Hebrew) is visible, the value returned is corresponding
261 Gregorian date in the form of the list (((month day year) STRING)). Returns
262 nil if it is not visible in the current calendar window."
263 (if (memq displayed-month
;; This test is only to speed things up a bit;
264 (list ;; it works fine without the test too.
265 (if (< 11 month
) (- month
11) (+ month
1))
266 (if (< 10 month
) (- month
10) (+ month
2))
267 (if (< 9 month
) (- month
9) (+ month
3))
268 (if (< 8 month
) (- month
8) (+ month
4))
269 (if (< 7 month
) (- month
7) (+ month
5))))
270 (let ((m1 displayed-month
)
275 (increment-calendar-month m1 y1 -
1)
276 (increment-calendar-month m2 y2
1)
277 (let* ((start-date (calendar-absolute-from-gregorian
279 (end-date (calendar-absolute-from-gregorian
280 (list m2
(calendar-last-day-of-month m2 y2
) y2
)))
281 (hebrew-start (calendar-hebrew-from-absolute start-date
))
282 (hebrew-end (calendar-hebrew-from-absolute end-date
))
283 (hebrew-y1 (extract-calendar-year hebrew-start
))
284 (hebrew-y2 (extract-calendar-year hebrew-end
)))
285 (setq year
(if (< 6 month
) hebrew-y2 hebrew-y1
))
286 (let ((date (calendar-gregorian-from-absolute
287 (calendar-absolute-from-hebrew
288 (list month day year
)))))
289 (if (calendar-date-is-visible-p date
)
290 (list (list date string
))))))))
292 (defun holiday-sexp (sexp string
)
293 "Sexp holiday for dates in the calendar window.
294 SEXP is an expression in variable `year' evaluates to `date'.
296 STRING is an expression in `date' that evaluates to the holiday description
299 If `date' is visible in the calendar window, the holiday STRING is on that
300 date. If date is nil, or if the date is not visible, there is no holiday."
301 (let ((m displayed-month
)
303 (increment-calendar-month m y -
1)
304 (filter-visible-calendar-holidays
308 (string (if date
(eval string
))))
309 (list (list date string
)))
312 (string (if date
(eval string
))))
313 (list (list date string
)))))))
315 (defun holiday-advent ()
316 "Date of Advent, if visible in calendar window."
317 (let ((year displayed-year
)
318 (month displayed-month
))
319 (increment-calendar-month month year -
1)
320 (let ((advent (calendar-gregorian-from-absolute
321 (calendar-dayname-on-or-before 0
322 (calendar-absolute-from-gregorian
323 (list 12 3 year
))))))
324 (if (calendar-date-is-visible-p advent
)
325 (list (list advent
"Advent"))))))
327 (defun holiday-easter-etc ()
328 "List of dates related to Easter, as visible in calendar window."
329 (if (and (> displayed-month
5) (not all-christian-calendar-holidays
))
330 nil
;; Ash Wednesday, Good Friday, and Easter are not visible.
331 (let* ((century (1+ (/ displayed-year
100)))
332 (shifted-epact ;; Age of moon for April 5...
333 (%
(+ 14 (* 11 (% displayed-year
19));; ...by Nicaean rule
334 (- ;; ...corrected for the Gregorian century rule
336 (/ ;; ...corrected for Metonic cycle inaccuracy.
337 (+ 5 (* 8 century
)) 25)
338 (* 30 century
));; Keeps value positive.
340 (adjusted-epact ;; Adjust for 29.5 day month.
341 (if (or (= shifted-epact
0)
342 (and (= shifted-epact
1) (< 10 (% displayed-year
19))))
345 (paschal-moon ;; Day after the full moon on or after March 21.
346 (- (calendar-absolute-from-gregorian (list 4 19 displayed-year
))
348 (abs-easter (calendar-dayname-on-or-before 0 (+ paschal-moon
7)))
351 (list (calendar-gregorian-from-absolute abs-easter
)
353 (list (calendar-gregorian-from-absolute (- abs-easter
2))
355 (list (calendar-gregorian-from-absolute (- abs-easter
46))
359 (list (calendar-gregorian-from-absolute (- abs-easter
63))
360 "Septuagesima Sunday")
361 (list (calendar-gregorian-from-absolute (- abs-easter
56))
363 (list (calendar-gregorian-from-absolute (- abs-easter
49))
365 (list (calendar-gregorian-from-absolute (- abs-easter
48))
367 (list (calendar-gregorian-from-absolute (- abs-easter
47))
369 (list (calendar-gregorian-from-absolute (- abs-easter
14))
371 (list (calendar-gregorian-from-absolute (- abs-easter
7))
373 (list (calendar-gregorian-from-absolute (- abs-easter
3))
375 (list (calendar-gregorian-from-absolute (+ abs-easter
35))
377 (list (calendar-gregorian-from-absolute (+ abs-easter
39))
379 (list (calendar-gregorian-from-absolute (+ abs-easter
49))
380 "Pentecost (Whitsunday)")
381 (list (calendar-gregorian-from-absolute (+ abs-easter
50))
383 (list (calendar-gregorian-from-absolute (+ abs-easter
56))
385 (list (calendar-gregorian-from-absolute (+ abs-easter
60))
388 (filter-visible-calendar-holidays mandatory
)))
389 (if all-christian-calendar-holidays
392 (filter-visible-calendar-holidays optional
)
396 (defun holiday-greek-orthodox-easter ()
397 "Date of Easter according to the rule of the Council of Nicaea."
398 (let ((m displayed-month
)
400 (increment-calendar-month m y
1)
402 (extract-calendar-year
403 (calendar-julian-from-absolute
404 (calendar-absolute-from-gregorian
405 (list m
(calendar-last-day-of-month m y
) y
)))))
406 (shifted-epact ;; Age of moon for April 5.
408 (* 11 (% julian-year
19)))
410 (paschal-moon ;; Day after full moon on or after March 21.
411 (- (calendar-absolute-from-julian (list 4 19 julian-year
))
413 (nicaean-easter;; Sunday following the Paschal moon
414 (calendar-gregorian-from-absolute
415 (calendar-dayname-on-or-before 0 (+ paschal-moon
7)))))
416 (if (calendar-date-is-visible-p nicaean-easter
)
417 (list (list nicaean-easter
"Pascha (Greek Orthodox Easter)"))))))
419 (defun holiday-rosh-hashanah-etc ()
420 "List of dates related to Rosh Hashanah, as visible in calendar window."
421 (if (or (< displayed-month
8)
422 (> displayed-month
11))
423 nil
;; None of the dates is visible
424 (let* ((abs-r-h (calendar-absolute-from-hebrew
425 (list 7 1 (+ displayed-year
3761))))
428 (list (calendar-gregorian-from-absolute abs-r-h
)
429 (format "Rosh HaShanah %d" (+ 3761 displayed-year
)))
430 (list (calendar-gregorian-from-absolute (+ abs-r-h
9))
432 (list (calendar-gregorian-from-absolute (+ abs-r-h
14))
434 (list (calendar-gregorian-from-absolute (+ abs-r-h
21))
436 (list (calendar-gregorian-from-absolute (+ abs-r-h
22))
440 (list (calendar-gregorian-from-absolute
441 (calendar-dayname-on-or-before 6 (- abs-r-h
4)))
443 (list (calendar-gregorian-from-absolute (1- abs-r-h
))
444 "Erev Rosh HaShannah")
445 (list (calendar-gregorian-from-absolute (1+ abs-r-h
))
446 "Rosh HaShanah (second day)")
447 (list (calendar-gregorian-from-absolute
448 (if (= (% abs-r-h
7) 4) (+ abs-r-h
3) (+ abs-r-h
2)))
450 (list (calendar-gregorian-from-absolute
451 (calendar-dayname-on-or-before 6 (+ 7 abs-r-h
)))
453 (list (calendar-gregorian-from-absolute (+ abs-r-h
8))
455 (list (calendar-gregorian-from-absolute (+ abs-r-h
13))
457 (list (calendar-gregorian-from-absolute (+ abs-r-h
15))
458 "Sukkot (second day)")
459 (list (calendar-gregorian-from-absolute (+ abs-r-h
16))
460 "Hol Hamoed Sukkot (first day)")
461 (list (calendar-gregorian-from-absolute (+ abs-r-h
17))
462 "Hol Hamoed Sukkot (second day)")
463 (list (calendar-gregorian-from-absolute (+ abs-r-h
18))
464 "Hol Hamoed Sukkot (third day)")
465 (list (calendar-gregorian-from-absolute (+ abs-r-h
19))
466 "Hol Hamoed Sukkot (fourth day)")
467 (list (calendar-gregorian-from-absolute (+ abs-r-h
20))
468 "Hoshannah Rabbah")))
470 (filter-visible-calendar-holidays mandatory
)))
471 (if all-hebrew-calendar-holidays
474 (filter-visible-calendar-holidays optional
)
478 (defun holiday-hanukkah ()
479 "List of dates related to Hanukkah, as visible in calendar window."
480 (if (memq displayed-month
;; This test is only to speed things up a bit;
481 '(10 11 12 1 2));; it works fine without the test too.
482 (let ((m displayed-month
)
484 (increment-calendar-month m y
1)
485 (let* ((h-y (extract-calendar-year
486 (calendar-hebrew-from-absolute
487 (calendar-absolute-from-gregorian
488 (list m
(calendar-last-day-of-month m y
) y
)))))
489 (abs-h (calendar-absolute-from-hebrew (list 9 25 h-y
))))
490 (filter-visible-calendar-holidays
492 (list (calendar-gregorian-from-absolute (1- abs-h
))
494 (list (calendar-gregorian-from-absolute abs-h
)
495 "Hanukkah (first day)")
496 (list (calendar-gregorian-from-absolute (1+ abs-h
))
497 "Hanukkah (second day)")
498 (list (calendar-gregorian-from-absolute (+ abs-h
2))
499 "Hanukkah (third day)")
500 (list (calendar-gregorian-from-absolute (+ abs-h
3))
501 "Hanukkah (fourth day)")
502 (list (calendar-gregorian-from-absolute (+ abs-h
4))
503 "Hanukkah (fifth day)")
504 (list (calendar-gregorian-from-absolute (+ abs-h
5))
505 "Hanukkah (sixth day)")
506 (list (calendar-gregorian-from-absolute (+ abs-h
6))
507 "Hanukkah (seventh day)")
508 (list (calendar-gregorian-from-absolute (+ abs-h
7))
509 "Hanukkah (eighth day)")))))))
511 (defun holiday-passover-etc ()
512 "List of dates related to Passover, as visible in calendar window."
513 (if (< 7 displayed-month
)
514 nil
;; None of the dates is visible
515 (let* ((abs-p (calendar-absolute-from-hebrew
516 (list 1 15 (+ displayed-year
3760))))
519 (list (calendar-gregorian-from-absolute abs-p
)
521 (list (calendar-gregorian-from-absolute (+ abs-p
50))
525 (list (calendar-gregorian-from-absolute
526 (calendar-dayname-on-or-before 6 (- abs-p
43)))
528 (list (calendar-gregorian-from-absolute
529 (calendar-dayname-on-or-before 6 (- abs-p
30)))
531 (list (calendar-gregorian-from-absolute
532 (if (= (% abs-p
7) 2) (- abs-p
33) (- abs-p
31)))
534 (list (calendar-gregorian-from-absolute (- abs-p
31))
536 (list (calendar-gregorian-from-absolute (- abs-p
30))
538 (list (calendar-gregorian-from-absolute
539 (if (zerop (% abs-p
7)) (- abs-p
28) (- abs-p
29)))
541 (list (calendar-gregorian-from-absolute
542 (- (calendar-dayname-on-or-before 6 (- abs-p
14)) 7))
544 (list (calendar-gregorian-from-absolute
545 (calendar-dayname-on-or-before 6 (- abs-p
14)))
547 (list (calendar-gregorian-from-absolute
548 (calendar-dayname-on-or-before 6 (1- abs-p
)))
550 (list (calendar-gregorian-from-absolute (1- abs-p
))
552 (list (calendar-gregorian-from-absolute (1+ abs-p
))
553 "Passover (second day)")
554 (list (calendar-gregorian-from-absolute (+ abs-p
2))
555 "Hol Hamoed Passover (first day)")
556 (list (calendar-gregorian-from-absolute (+ abs-p
3))
557 "Hol Hamoed Passover (second day)")
558 (list (calendar-gregorian-from-absolute (+ abs-p
4))
559 "Hol Hamoed Passover (third day)")
560 (list (calendar-gregorian-from-absolute (+ abs-p
5))
561 "Hol Hamoed Passover (fourth day)")
562 (list (calendar-gregorian-from-absolute (+ abs-p
6))
563 "Passover (seventh day)")
564 (list (calendar-gregorian-from-absolute (+ abs-p
7))
565 "Passover (eighth day)")
566 (list (calendar-gregorian-from-absolute (+ abs-p
12))
568 (list (calendar-gregorian-from-absolute
569 (if (zerop (% abs-p
7))
571 (if (= (% abs-p
7) 6)
575 (list (calendar-gregorian-from-absolute (+ abs-p
33))
577 (list (calendar-gregorian-from-absolute (+ abs-p
43))
579 (list (calendar-gregorian-from-absolute (+ abs-p
49))
581 (list (calendar-gregorian-from-absolute (+ abs-p
51))
582 "Shavuot (second day)")))
584 (filter-visible-calendar-holidays mandatory
)))
585 (if all-hebrew-calendar-holidays
588 (filter-visible-calendar-holidays optional
)
592 (defun holiday-tisha-b-av-etc ()
593 "List of dates around Tisha B'Av, as visible in calendar window."
594 (if (or (< displayed-month
5)
595 (> displayed-month
9))
596 nil
;; None of the dates is visible
597 (let* ((abs-t-a (calendar-absolute-from-hebrew
598 (list 5 9 (+ displayed-year
3760)))))
600 (filter-visible-calendar-holidays
602 (list (calendar-gregorian-from-absolute
603 (if (= (% abs-t-a
7) 6) (- abs-t-a
20) (- abs-t-a
21)))
605 (list (calendar-gregorian-from-absolute
606 (calendar-dayname-on-or-before 6 abs-t-a
))
608 (list (calendar-gregorian-from-absolute
609 (if (= (% abs-t-a
7) 6) (1+ abs-t-a
) abs-t-a
))
611 (list (calendar-gregorian-from-absolute
612 (calendar-dayname-on-or-before 6 (+ abs-t-a
7)))
613 "Shabbat Nahamu"))))))
615 (defun filter-visible-calendar-holidays (l)
616 "Return a list of all visible holidays of those on L."
621 (calendar-date-is-visible-p (car (car p
)))
622 (setq visible
(append (list (car p
)) visible
)))
628 ;;; holidays.el ends here