;;; holidays.el --- holiday functions for the calendar package
-;; Copyright (C) 1989, 1990, 1992, 1993, 1994 Free Software Foundation, Inc.
+;; Copyright (C) 1989, 1990, 1992, 1993, 1994, 1997, 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: holidays, calendar
;; This file is part of GNU Emacs.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING. If not, write to the
-;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-;; Boston, MA 02111-1307, USA.
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
;;; Commentary:
;; This collection of functions implements the holiday features as described
;; in calendar.el.
-;; 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
-
;; 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. ``Calendrical Calculations, Part II: Three Historical
;; 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:
+(defvar displayed-month)
+(defvar displayed-year)
+
(require 'calendar)
(autoload 'holiday-julian "cal-julian"
"Holiday on MONTH, DAY (Islamic) called STRING."
t)
+(autoload 'holiday-bahai "cal-bahai"
+ "Holiday on MONTH, DAY (Baha'i) called STRING."
+ t)
+
(autoload 'holiday-chinese-new-year "cal-china"
"Date of Chinese New Year."
t)
Requires floating point."
t)
+;;;###autoload
(defun holidays (&optional arg)
"Display the holidays for last month, this month, and next month.
If called with an optional prefix argument, prompts for month and year.
(defun list-holidays (y1 y2 &optional l label)
"Display holidays for years Y1 to Y2 (inclusive).
-The optional list of holidays L defaults to `calendar-holidays'. See the
-documentation for that variable for a description of holiday lists.
+The optional list of holidays L defaults to `calendar-holidays'.
+If you want to control what holidays are displayed, use a
+different list. For example,
+
+ (list-holidays 2006 2006
+ (append general-holidays local-holidays other-holidays))
+
+will display holidays for the year 2006 defined in the 3
+mentioned lists, and nothing else.
+
+When called interactively, this command offers a choice of
+holidays, based on the variables `solar-holidays' etc. See the
+documentation of `calendar-holidays' for a list of the variables
+that control the choices, as well as a description of the format
+of a holiday list.
The optional LABEL is used to label the buffer created."
(interactive
(if christian-holidays (cons "Christian" christian-holidays))
(if hebrew-holidays (cons "Hebrew" hebrew-holidays))
(if islamic-holidays (cons "Islamic" islamic-holidays))
+ (if bahai-holidays (cons "Baha'i" bahai-holidays))
(if oriental-holidays (cons "Oriental" oriental-holidays))
(if solar-holidays (cons "Solar" solar-holidays))
(cons "Ask" nil)))
(cdr (assoc choice lists))))
(name (if (string-equal choice "Equinoxes/Solstices")
choice
- (if (string-equal choice "Ask")
- "Holidays"
+ (if (member choice '("Ask" ""))
+ "Holidays"
(format "%s Holidays" choice)))))
(list start-year end-year which name)))
(message "Computing holidays...")
(let* ((holiday-buffer "*Holidays*")
(calendar-holidays (if l l calendar-holidays))
- (title (if label label "Holidays"))
+ (title (or label "Holidays"))
(holiday-list nil)
(s (calendar-absolute-from-gregorian (list 2 1 y1)))
(e (calendar-absolute-from-gregorian (list 11 1 y2)))
(increment-calendar-month displayed-month displayed-year 3)
(setq d (calendar-absolute-from-gregorian
(list displayed-month 1 displayed-year))))
- (set-buffer (get-buffer-create holiday-buffer))
- (setq buffer-read-only nil)
- (calendar-set-mode-line
- (if (= y1 y2)
- (format "%s for %s" label y1)
- (format "%s for %s-%s" label y1 y2)))
- (erase-buffer)
- (goto-char (point-min))
- (insert
- (mapconcat
- '(lambda (x) (concat (calendar-date-string (car x)) ": " (car (cdr x))))
- holiday-list "\n"))
- (goto-char (point-min))
- (set-buffer-modified-p nil)
- (setq buffer-read-only t)
- (display-buffer holiday-buffer)
- (message "Computing holidays...done")))
+ (save-excursion
+ (set-buffer (get-buffer-create holiday-buffer))
+ (setq buffer-read-only nil)
+ (calendar-set-mode-line
+ (if (= y1 y2)
+ (format "%s for %s" title y1)
+ (format "%s for %s-%s" title y1 y2)))
+ (erase-buffer)
+ (goto-char (point-min))
+ (insert
+ (mapconcat
+ '(lambda (x) (concat (calendar-date-string (car x))
+ ": " (car (cdr x))))
+ holiday-list "\n"))
+ (goto-char (point-min))
+ (set-buffer-modified-p nil)
+ (setq buffer-read-only t)
+ (display-buffer holiday-buffer)
+ (message "Computing holidays...done"))))
+
(defun check-calendar-holidays (date)
"Check the list of holidays for any that occur on DATE.
(list (list (list month day y) string)))))
(defun holiday-float (month dayname n string &optional day)
- "Holiday on MONTH, DAYNAME (Nth occurrence, Gregorian) called STRING.
+ "Holiday on MONTH, DAYNAME (Nth occurrence) called STRING.
If the Nth DAYNAME in MONTH is visible, the value returned is the list
\(((MONTH DAY year) STRING)).
If N<0, count backward from the end of MONTH.
-An optional parameter DAY means the Nth DAYNAME after/before MONTH DAY.
+An optional parameter DAY means the Nth DAYNAME on or after/before MONTH DAY.
Returns nil if it is not visible in the current calendar window."
- (let ((m displayed-month)
- (y displayed-year))
- (increment-calendar-month m y (- 11 month))
- (if (> m 9)
- (list (list (calendar-nth-named-day n dayname month y day) string)))))
+;; This is messy because the holiday may be visible, while the date on which
+;; it is based is not. For example, the first Monday after December 30 may be
+;; visible when January is not. For large values of |n| the problem is more
+;; grotesque. If we didn't have to worry about such cases, we could just use
+
+;; (let ((m displayed-month)
+;; (y displayed-year))
+;; (increment-calendar-month m y (- 11 month))
+;; (if (> m 9); month in year y is visible
+;; (list (list (calendar-nth-named-day n dayname month y day) string)))))
+
+;; which is the way the function was originally written.
+
+ (let* ((m1 displayed-month)
+ (y1 displayed-year)
+ (m2 m1)
+ (y2 y1))
+ (increment-calendar-month m1 y1 -1)
+ (increment-calendar-month m2 y2 1)
+ (let* ((d1; first possible base date for holiday
+ (+ (calendar-nth-named-absday 1 dayname m1 y1)
+ (* -7 n)
+ (if (> n 0) 1 -7)))
+ (d2; last possible base date for holiday
+ (+ (calendar-nth-named-absday -1 dayname m2 y2)
+ (* -7 n)
+ (if (> n 0) 7 -1)))
+ (y1 (extract-calendar-year (calendar-gregorian-from-absolute d1)))
+ (y2 (extract-calendar-year (calendar-gregorian-from-absolute d2)))
+ (y; year of base date
+ (if (or (= y1 y2) (> month 9))
+ y1
+ y2))
+ (d; day of base date
+ (or day (if (> n 0)
+ 1
+ (calendar-last-day-of-month month y))))
+ (date; base date for holiday
+ (calendar-absolute-from-gregorian (list month d y))))
+ (if (and (<= d1 date) (<= date d2))
+ (list (list (calendar-nth-named-day n dayname month y d)
+ string))))))
(defun holiday-sexp (sexp string)
"Sexp holiday for dates in the calendar window.
(string (if date (eval string))))
(list (list date string)))))))
-(defun holiday-advent ()
- "Date of Advent, if visible in calendar window."
- (let ((year displayed-year)
- (month displayed-month))
- (increment-calendar-month month year -1)
- (let ((advent (calendar-gregorian-from-absolute
- (calendar-dayname-on-or-before 0
- (calendar-absolute-from-gregorian
- (list 12 3 year))))))
- (if (calendar-date-is-visible-p advent)
- (list (list advent "Advent"))))))
-
-(defun holiday-easter-etc ()
- "List of dates related to Easter, as visible in calendar window."
- (if (and (> displayed-month 5) (not all-christian-calendar-holidays))
- nil;; Ash Wednesday, Good Friday, and Easter are not visible.
- (let* ((century (1+ (/ displayed-year 100)))
- (shifted-epact ;; Age of moon for April 5...
- (% (+ 14 (* 11 (% displayed-year 19));; ...by Nicaean rule
- (- ;; ...corrected for the Gregorian century rule
- (/ (* 3 century) 4))
- (/ ;; ...corrected for Metonic cycle inaccuracy.
- (+ 5 (* 8 century)) 25)
- (* 30 century));; Keeps value positive.
- 30))
- (adjusted-epact ;; Adjust for 29.5 day month.
- (if (or (= shifted-epact 0)
- (and (= shifted-epact 1) (< 10 (% displayed-year 19))))
- (1+ shifted-epact)
- shifted-epact))
- (paschal-moon ;; Day after the full moon on or after March 21.
- (- (calendar-absolute-from-gregorian (list 4 19 displayed-year))
- adjusted-epact))
- (abs-easter (calendar-dayname-on-or-before 0 (+ paschal-moon 7)))
- (mandatory
- (list
- (list (calendar-gregorian-from-absolute abs-easter)
- "Easter Sunday")
- (list (calendar-gregorian-from-absolute (- abs-easter 2))
- "Good Friday")
- (list (calendar-gregorian-from-absolute (- abs-easter 46))
- "Ash Wednesday")))
- (optional
- (list
- (list (calendar-gregorian-from-absolute (- abs-easter 63))
- "Septuagesima Sunday")
- (list (calendar-gregorian-from-absolute (- abs-easter 56))
- "Sexagesima Sunday")
- (list (calendar-gregorian-from-absolute (- abs-easter 49))
- "Shrove Sunday")
- (list (calendar-gregorian-from-absolute (- abs-easter 48))
- "Shrove Monday")
- (list (calendar-gregorian-from-absolute (- abs-easter 47))
- "Shrove Tuesday")
- (list (calendar-gregorian-from-absolute (- abs-easter 14))
- "Passion Sunday")
- (list (calendar-gregorian-from-absolute (- abs-easter 7))
- "Palm Sunday")
- (list (calendar-gregorian-from-absolute (- abs-easter 3))
- "Maundy Thursday")
- (list (calendar-gregorian-from-absolute (+ abs-easter 35))
- "Rogation Sunday")
- (list (calendar-gregorian-from-absolute (+ abs-easter 39))
- "Ascension Day")
- (list (calendar-gregorian-from-absolute (+ abs-easter 49))
- "Pentecost (Whitsunday)")
- (list (calendar-gregorian-from-absolute (+ abs-easter 50))
- "Whitmonday")
- (list (calendar-gregorian-from-absolute (+ abs-easter 56))
- "Trinity Sunday")
- (list (calendar-gregorian-from-absolute (+ abs-easter 60))
- "Corpus Christi")))
- (output-list
- (filter-visible-calendar-holidays mandatory)))
- (if all-christian-calendar-holidays
- (setq output-list
- (append
- (filter-visible-calendar-holidays optional)
- output-list)))
- output-list)))
+(defun holiday-advent (&optional n string)
+ "Date of Nth day after advent (named STRING), if visible in calendar window.
+Negative values of N are interpreted as days before advent.
+STRING is used purely for display purposes. The return value has
+the form ((MONTH DAY YEAR) STRING), where the date is that of the
+Nth day before or after advent.
+
+For backwards compatibility, if this function is called with no
+arguments, then it returns the value appropriate for advent itself."
+ ;; Backwards compatibility layer.
+ (if (not n)
+ (holiday-advent 0 "Advent")
+ (let ((year displayed-year)
+ (month displayed-month))
+ (increment-calendar-month month year -1)
+ (let ((advent (calendar-gregorian-from-absolute
+ (+ n
+ (calendar-dayname-on-or-before
+ 0
+ (calendar-absolute-from-gregorian
+ (list 12 3 year)))))))
+ (if (calendar-date-is-visible-p advent)
+ (list (list advent string)))))))
+
+(defun holiday-easter-etc (&optional n string)
+ "Date of Nth day after Easter (named STRING), if visible in calendar window.
+Negative values of N are interpreted as days before Easter.
+STRING is used purely for display purposes. The return value has
+the form ((MONTH DAY YEAR) STRING), where the date is that of the
+Nth day before or after Easter.
+
+For backwards compatibility, if this function is called with no
+arguments, then it returns a list of \"standard\" Easter-related
+holidays (with more entries if `all-christian-calendar-holidays'
+is non-nil)."
+ ;; Backwards compatibility layer.
+ (if (not n)
+ (let (res-list res)
+ (dolist (elem (append
+ (if all-christian-calendar-holidays
+ '((-63 . "Septuagesima Sunday")
+ (-56 . "Sexagesima Sunday")
+ (-49 . "Shrove Sunday")
+ (-48 . "Shrove Monday")
+ (-47 . "Shrove Tuesday")
+ (-14 . "Passion Sunday")
+ (-7 . "Palm Sunday")
+ (-3 . "Maundy Thursday")
+ (35 . "Rogation Sunday")
+ (39 . "Ascension Day")
+ (49 . "Pentecost (Whitsunday)")
+ (50 . "Whitmonday")
+ (56 . "Trinity Sunday")
+ (60 . "Corpus Christi")))
+ '((0 . "Easter Sunday")
+ (-2 . "Good Friday")
+ (-46 . "Ash Wednesday")))
+ res-list)
+ ;; Filter out nil (not visible) values.
+ (if (setq res (holiday-easter-etc (car elem) (cdr elem)))
+ (setq res-list (append res res-list)))))
+ (let* ((century (1+ (/ displayed-year 100)))
+ (shifted-epact ;; Age of moon for April 5...
+ (% (+ 14 (* 11 (% displayed-year 19)) ;; ...by Nicaean rule
+ (- ;; ...corrected for the Gregorian century rule
+ (/ (* 3 century) 4))
+ (/ ;; ...corrected for Metonic cycle inaccuracy.
+ (+ 5 (* 8 century)) 25)
+ (* 30 century)) ;; Keeps value positive.
+ 30))
+ (adjusted-epact ;; Adjust for 29.5 day month.
+ (if (or (zerop shifted-epact)
+ (and (= shifted-epact 1) (< 10 (% displayed-year 19))))
+ (1+ shifted-epact)
+ shifted-epact))
+ (paschal-moon ;; Day after the full moon on or after March 21.
+ (- (calendar-absolute-from-gregorian (list 4 19 displayed-year))
+ adjusted-epact))
+ (abs-easter (calendar-dayname-on-or-before 0 (+ paschal-moon 7))))
+ (filter-visible-calendar-holidays
+ (list (list (calendar-gregorian-from-absolute (+ abs-easter n))
+ string))))))
(defun holiday-greek-orthodox-easter ()
"Date of Easter according to the rule of the Council of Nicaea."
(provide 'holidays)
+;;; arch-tag: 48eb3117-75a7-4dbe-8fd9-873c3cbb0d37
;;; holidays.el ends here