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1 ;;; cal-china.el --- calendar functions for the Chinese calendar
3 ;; Copyright (C) 1995, 1997, 2001-2017 Free Software Foundation, Inc.
5 ;; Author: Edward M. Reingold <reingold@cs.uiuc.edu>
6 ;; Maintainer: Glenn Morris <rgm@gnu.org>
7 ;; Keywords: calendar
8 ;; Human-Keywords: Chinese calendar, calendar, holidays, diary
9 ;; Package: calendar
11 ;; This file is part of GNU Emacs.
13 ;; GNU Emacs is free software: you can redistribute it and/or modify
14 ;; it under the terms of the GNU General Public License as published by
15 ;; the Free Software Foundation, either version 3 of the License, or
16 ;; (at your option) any later version.
18 ;; GNU Emacs is distributed in the hope that it will be useful,
19 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 ;; GNU General Public License for more details.
23 ;; You should have received a copy of the GNU General Public License
24 ;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
26 ;;; Commentary:
28 ;; See calendar.el.
30 ;; The rules used for the Chinese calendar are those of Baolin Liu
31 ;; (see L. E. Doggett's article "Calendars" in the Explanatory
32 ;; Supplement to the Astronomical Almanac, second edition, 1992) for
33 ;; the calendar as revised at the beginning of the Qing dynasty in
34 ;; 1644. The nature of the astronomical calculations is such that
35 ;; precise calculations cannot be made without great expense in time,
36 ;; so that the calendars produced may not agree perfectly with
37 ;; published tables--but no two pairs of published tables agree
38 ;; perfectly either! Liu's rules produce a calendar for 2033 which is
39 ;; not accepted by all authorities. The date of Chinese New Year is
40 ;; correct from 1644-2051.
42 ;; Note to maintainers:
43 ;; Use `chinese-year-cache-init' every few years to recenter the default
44 ;; value of `chinese-year-cache'.
46 ;;; Code:
50 ;; solar-date-next-longitude brought in by lunar.
51 ;;;(require 'solar)
52 ;; calendar-astro-to-absolute and from-absolute are cal-autoloads.
53 ;;;(require 'cal-julian)
57 "Chinese calendar support."
65 "Minutes difference between local standard time for Chinese calendar and UTC.
66 Default is for Beijing. This is an expression in `year' since it changed at
67 1928-01-01 00:00:00 from UT+7:45:40 to UT+8."
71 ;; It gets eval'd.
72 ;;;###autoload
75 ;; FIXME unused.
77 "Name of location used for calculation of Chinese calendar."
82 ;; The correct value is as follows, but the Chinese calendrical
83 ;; authorities do NOT use DST in determining astronomical events:
84 ;; 60
85 "Minutes difference between daylight saving and standard time.
86 Default is for no daylight saving time."
92 "PMT"
94 "Abbreviated name of standard time zone used for Chinese calendar.
95 This is an expression depending on `year' because it changed
96 at 1928-01-01 00:00:00 from `PMT' to `CST'."
98 :risky t
102 "Abbreviated name of daylight saving time zone used for Chinese calendar."
107 ;; The correct value is as follows, but the Chinese calendrical
108 ;; authorities do NOT use DST in determining astronomical events:
109 ;; '(cond ((< 1986 year) (calendar-nth-named-day 1 0 4 year 10))
110 ;; ((= 1986 year) '(5 4 1986))
111 ;; (t nil))
112 "Sexp giving the date on which daylight saving time starts.
113 Default is for no daylight saving time. See documentation of
114 `calendar-daylight-savings-starts'."
116 :risky t
120 ;; The correct value is as follows, but the Chinese calendrical
121 ;; authorities do NOT use DST in determining astronomical events:
122 ;; '(if (<= 1986 year) (calendar-nth-named-day 1 0 9 year 11))
123 "Sexp giving the date on which daylight saving time ends.
124 Default is for no daylight saving time. See documentation of
125 `calendar-daylight-savings-ends'."
127 :risky t
131 "Number of minutes after midnight that daylight saving time starts.
132 Default is for no daylight saving time."
137 "Number of minutes after midnight that daylight saving time ends.
138 Default is for no daylight saving time."
144 "Prefixes used by `calendar-chinese-sexagesimal-name'."
159 "Suffixes used by `calendar-chinese-sexagesimal-name'."
174 ;;; End of user options.
178 "The N-th name of the Chinese sexagesimal cycle.
179 N congruent to 1 gives the first name, N congruent to 2 gives the second name,
180 ..., N congruent to 60 gives the sixtieth name."
186 "Absolute date of first new Zodiac sign on or after absolute date D.
187 The Zodiac signs begin when the sun's longitude is a multiple of 30 degrees."
191 calendar-chinese-daylight-time-offset)
193 calendar-chinese-standard-time-zone-name)
195 calendar-chinese-daylight-time-zone-name)
197 calendar-chinese-daylight-saving-start)
199 calendar-chinese-daylight-saving-end)
201 calendar-chinese-daylight-saving-start-time)
203 calendar-chinese-daylight-saving-end-time))
209 "Absolute date of first new moon on or after absolute date D."
213 calendar-chinese-daylight-time-offset)
215 calendar-chinese-standard-time-zone-name)
217 calendar-chinese-daylight-time-zone-name)
219 calendar-chinese-daylight-saving-start)
221 calendar-chinese-daylight-saving-end)
223 calendar-chinese-daylight-saving-start-time)
225 calendar-chinese-daylight-saving-end-time))
231 "List of starting dates of Chinese months from START to END."
239 "Assign month numbers to the lunar months in LIST, starting with START.
240 Numbers are assigned sequentially, START, START+1, ..., 11, with
241 half numbers used for leap months. First and last months of list
242 are never leap months."
245 ;; Remaining months.
247 ;; List is too short for a leap month.
253 ;; Next month is a leap month.
256 ;; Next month is not a leap month.
260 "Compute the structure of the Chinese year for Gregorian year Y.
261 The result is a list of pairs (i d), where month i begins on absolute date d,
262 of the Chinese months from the Chinese month following the solstice in
263 Gregorian year Y-1 to the Chinese month of the solstice of Gregorian year Y."
271 next-solstice))
274 ;; No room for a leap month, just number them 12, 1, 2, ..., 11.
277 ;; Now we can assign numbers to the list for y.
278 ;; The first month or two are special.
280 ;; First month on list is a leap month, second is not.
284 ;; First month on list is not a leap month.
288 ;; Second month on list is a leap month.
291 ;; Second month on list is not a leap month.
295 ;; Maintainers: delete existing value, position point at start of
296 ;; empty line, then call M-: (calendar-chinese-year-cache-init N)
347 "Alist of Chinese year structures as determined by `chinese-year'.
351 "The structure of the Chinese year for Gregorian year Y.
352 The result is a list of pairs (i d), where month i begins on absolute date d,
353 of the Chinese months from the Chinese month following the solstice in
354 Gregorian year Y-1 to the Chinese month of the solstice of Gregorian year Y.
355 The list is cached in `calendar-chinese-year-cache' for further use."
361 list))
363 ;; Maintainer use.
365 "Insert an initialization value for `calendar-chinese-year-cache' after point.
366 Computes values for 10 years either side of YEAR."
378 ;; fill-column -/+ 5.
386 "The number of days elapsed between the Gregorian date 12/31/1 BC and DATE.
387 DATE is a Chinese date (cycle year month day). The Gregorian date
388 Sunday, December 31, 1 BC is imaginary."
403 "Compute Chinese date (cycle year month day) corresponding to absolute DATE.
404 The absolute date is the number of days elapsed since the (imaginary)
405 Gregorian date Sunday, December 31, 1 BC."
413 ;; The first month on the list is in Chinese year c-year.
414 ;; Date is on or after start of second month on list...
416 ;; Second month on list is a new Chinese year...
418 ;; ...so first month on list is of no interest.
421 ;; Remainder of c-year/60 with 60 instead of 0.
426 ;; Bound in calendar-generate.
430 ;;;###holiday-autoload
432 "Date of Chinese New Year, if visible in calendar.
433 Returns (((MONTH DAY YEAR) TEXT)), where the date is Gregorian."
436 chinese-new-year)
437 ;; In the Gregorian calendar, CNY falls between Jan 21 and Feb 20.
438 ;; Jan is visible if displayed-month = 12, 1, 2; Feb if d-m = 1, 2, 3.
439 ;; If we shift the calendar forward one month, we can do a
440 ;; one-sided test, namely: d-m <= 4 means CNY might be visible.
452 ;;;###holiday-autoload
454 "Date of Chinese Qingming Festival, if visible in calendar.
455 Returns (((MONTH DAY YEAR) TEXT)), where the date is Gregorian."
458 ;; 15 days after Vernal Equinox.
465 ;;;###holiday-autoload
467 "Date of Chinese winter solstice, if visible in calendar.
468 Returns (((MONTH DAY YEAR) TEXT)), where the date is Gregorian."
475 displayed-year)))))
478 ;;;###holiday-autoload
480 "Holiday on Chinese MONTH, DAY called STRING.
481 If MONTH, DAY (Chinese) is visible, returns the corresponding
482 Gregorian date as the list (((month day year) STRING)).
483 Returns nil if it is not visible in the current calendar window."
486 ;; A basic optimization. Chinese year can only change if
487 ;; Jan or Feb are visible. FIXME can we do more?
489 ;; This is calendar-nongregorian-visible-p adapted for
490 ;; the form of chinese dates: (cycle year month day) as
491 ;; opposed to (month day year).
496 ;; Absolute date of first/last dates in calendar window.
505 y2))))
506 ;; Local date of first/last date in calendar window.
509 ;; When Chinese New Year is visible on the far
510 ;; right of the calendar, what is the earliest
511 ;; Chinese month in the previous year that might
512 ;; still visible? This test doesn't have to be precise.
517 ;; Simple form for when new years are not visible.
523 ;;;###cal-autoload
525 "String of Chinese date of Gregorian DATE.
526 Defaults to today's date if DATE is not given."
539 ;; Remainder of (1+(floor month))/12, with
540 ;; 12 instead of 0.
544 cycle
547 "second "
549 "first "
558 ;;;###cal-autoload
560 "Show the Chinese date equivalents of date."
567 "Make list of months L into an assoc list."
581 "A list of the months in cycle C, year Y of the Chinese calendar."
598 ;;;###cal-autoload
600 "Move cursor to Chinese date DATE.
601 Echo Chinese date unless NOECHO is non-nil."
606 "Chinese calendar cycle number (>44): "
610 "Year in Chinese cycle (1..60): "
617 month-list nil t)
618 month-list)))
625 30
637 ;; To be called from diary-list-sexp-entries, where DATE is bound.
638 ;;;###diary-autoload
640 "Chinese calendar equivalent of date diary entry."
643 ;;;; diary support
659 ;;; NOTE: In the diary the cycle and year of a Chinese date is
660 ;;; combined using this formula: (+ (* cycle 100) year).
661 ;;;
662 ;;; These two functions convert to and back from this representation.
665 ;; Note: For leap months M is a float.
681 #'calendar-chinese-from-absolute-for-diary
682 #'calendar-chinese-to-absolute-for-diary
683 color)
686 #'calendar-chinese-from-absolute-for-diary
688 color)))
690 ;;;###cal-autoload
692 "Mark days in the calendar window that have Chinese date diary entries.
693 Marks each entry in `diary-file' (or included files) visible in the calendar
694 window. See `diary-chinese-list-entries' for more information.
696 This function is provided for use with `diary-nongregorian-marking-hook'."
698 calendar-chinese-month-name-array
699 diary-chinese-entry-symbol
702 ;;;###cal-autoload
704 "Add any Chinese date entries from the diary file to `diary-entries-list'.
705 Chinese date diary entries must be prefixed by `diary-chinese-entry-symbol'
706 \(normally a `C'). The same `diary-date-forms' govern the style
707 of the Chinese calendar entries. If a Chinese date diary entry begins with
708 `diary-nonmarking-symbol', the entry will appear in the diary listing,
709 but will not be marked in the calendar.
711 This function is provided for use with `diary-nongregorian-listing-hook'."
713 diary-chinese-entry-symbol
716 ;;;###cal-autoload
718 "Like `diary-anniversary' (which see) but accepts Chinese date."
733 ;; The Chinese month can differ by 0.5 in a leap month.
738 ;;;###cal-autoload
740 "Insert an anniversary diary entry for the Chinese date at point.
741 Prefix argument ARG makes the entry nonmarking."
746 diary-sexp-entry-symbol
750 arg)))
752 ;;;###cal-autoload
754 "Insert a diary entry for the Chinese date at point."
757 diary-chinese-entry-symbol
760 ;;;###cal-autoload
762 "Insert a monthly diary entry for the Chinese date at point."
765 diary-chinese-entry-symbol
768 ;;;###cal-autoload
770 "Insert a yearly diary entry for the Chinese date at point."
773 diary-chinese-entry-symbol
778 ;;; cal-china.el ends here