1;;; holidays.el --- holiday functions for the calendar package 2 3;; Copyright (C) 1989, 1990, 1992, 1993, 1994, 1997, 2001, 2002, 2003, 4;; 2004, 2005, 2006, 2007 Free Software Foundation, Inc. 5 6;; Author: Edward M. Reingold <reingold@cs.uiuc.edu> 7;; Maintainer: Glenn Morris <rgm@gnu.org> 8;; Keywords: holidays, calendar 9 10;; This file is part of GNU Emacs. 11 12;; GNU Emacs is free software; you can redistribute it and/or modify 13;; it under the terms of the GNU General Public License as published by 14;; the Free Software Foundation; either version 2, or (at your option) 15;; any later version. 16 17;; GNU Emacs is distributed in the hope that it will be useful, 18;; but WITHOUT ANY WARRANTY; without even the implied warranty of 19;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 20;; GNU General Public License for more details. 21 22;; You should have received a copy of the GNU General Public License 23;; along with GNU Emacs; see the file COPYING. If not, write to the 24;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 25;; Boston, MA 02110-1301, USA. 26 27;;; Commentary: 28 29;; This collection of functions implements the holiday features as described 30;; in calendar.el. 31 32;; Technical details of all the calendrical calculations can be found in 33;; ``Calendrical Calculations: The Millennium Edition'' by Edward M. Reingold 34;; and Nachum Dershowitz, Cambridge University Press (2001). 35 36;; An earlier version of the technical details appeared in 37;; ``Calendrical Calculations'' by Nachum Dershowitz and Edward M. Reingold, 38;; Software--Practice and Experience, Volume 20, Number 9 (September, 1990), 39;; pages 899-928. ``Calendrical Calculations, Part II: Three Historical 40;; Calendars'' by E. M. Reingold, N. Dershowitz, and S. M. Clamen, 41;; Software--Practice and Experience, Volume 23, Number 4 (April, 1993), 42;; pages 383-404. 43 44;; Hard copies of these two papers can be obtained by sending email to 45;; reingold@cs.uiuc.edu with the SUBJECT "send-paper-cal" (no quotes) and 46;; the message BODY containing your mailing address (snail). 47 48;;; Code: 49 50(defvar displayed-month) 51(defvar displayed-year) 52 53(require 'calendar) 54 55(autoload 'holiday-julian "cal-julian" 56 "Holiday on MONTH, DAY (Julian) called STRING." 57 t) 58 59(autoload 'holiday-hebrew "cal-hebrew" 60 "Holiday on MONTH, DAY (Hebrew) called STRING." 61 t) 62 63(autoload 'holiday-rosh-hashanah-etc "cal-hebrew" 64 "List of dates related to Rosh Hashanah, as visible in calendar window." 65 t) 66 67(autoload 'holiday-hanukkah "cal-hebrew" 68 "List of dates related to Hanukkah, as visible in calendar window." 69 t) 70 71(autoload 'holiday-passover-etc "cal-hebrew" 72 "List of dates related to Passover, as visible in calendar window." 73 t) 74 75(autoload 'holiday-tisha-b-av-etc "cal-hebrew" 76 "List of dates around Tisha B'Av, as visible in calendar window." 77 t) 78 79(autoload 'holiday-islamic "cal-islam" 80 "Holiday on MONTH, DAY (Islamic) called STRING." 81 t) 82 83(autoload 'holiday-bahai "cal-bahai" 84 "Holiday on MONTH, DAY (Baha'i) called STRING." 85 t) 86 87(autoload 'holiday-chinese-new-year "cal-china" 88 "Date of Chinese New Year." 89 t) 90 91(autoload 'solar-equinoxes-solstices "solar" 92 "Date and time of equinoxes and solstices, if visible in the calendar window. 93Requires floating point." 94 t) 95 96;;;###autoload 97(defun holidays (&optional arg) 98 "Display the holidays for last month, this month, and next month. 99If called with an optional prefix argument, prompts for month and year. 100 101This function is suitable for execution in a .emacs file." 102 (interactive "P") 103 (save-excursion 104 (let* ((completion-ignore-case t) 105 (date (if arg 106 (calendar-read-date t) 107 (calendar-current-date))) 108 (displayed-month (extract-calendar-month date)) 109 (displayed-year (extract-calendar-year date))) 110 (list-calendar-holidays)))) 111 112;;;###autoload 113(defun list-holidays (y1 y2 &optional l label) 114 "Display holidays for years Y1 to Y2 (inclusive). 115 116The optional list of holidays L defaults to `calendar-holidays'. 117If you want to control what holidays are displayed, use a 118different list. For example, 119 120 (list-holidays 2006 2006 121 (append general-holidays local-holidays other-holidays)) 122 123will display holidays for the year 2006 defined in the 3 124mentioned lists, and nothing else. 125 126When called interactively, this command offers a choice of 127holidays, based on the variables `solar-holidays' etc. See the 128documentation of `calendar-holidays' for a list of the variables 129that control the choices, as well as a description of the format 130of a holiday list. 131 132The optional LABEL is used to label the buffer created." 133 (interactive 134 (let* ((start-year (calendar-read 135 "Starting year of holidays (>0): " 136 '(lambda (x) (> x 0)) 137 (int-to-string (extract-calendar-year 138 (calendar-current-date))))) 139 (end-year (calendar-read 140 (format "Ending year (inclusive) of holidays (>=%s): " 141 start-year) 142 '(lambda (x) (>= x start-year)) 143 (int-to-string start-year))) 144 (completion-ignore-case t) 145 (lists 146 (list 147 (cons "All" calendar-holidays) 148 (if (fboundp 'atan) 149 (cons "Equinoxes/Solstices" 150 (list (list 'solar-equinoxes-solstices)))) 151 (if general-holidays (cons "General" general-holidays)) 152 (if local-holidays (cons "Local" local-holidays)) 153 (if other-holidays (cons "Other" other-holidays)) 154 (if christian-holidays (cons "Christian" christian-holidays)) 155 (if hebrew-holidays (cons "Hebrew" hebrew-holidays)) 156 (if islamic-holidays (cons "Islamic" islamic-holidays)) 157 (if bahai-holidays (cons "Baha'i" bahai-holidays)) 158 (if oriental-holidays (cons "Oriental" oriental-holidays)) 159 (if solar-holidays (cons "Solar" solar-holidays)) 160 (cons "Ask" nil))) 161 (choice (capitalize 162 (completing-read "List (TAB for choices): " lists nil t))) 163 (which (if (string-equal choice "Ask") 164 (eval (read-variable "Enter list name: ")) 165 (cdr (assoc choice lists)))) 166 (name (if (string-equal choice "Equinoxes/Solstices") 167 choice 168 (if (member choice '("Ask" "")) 169 "Holidays" 170 (format "%s Holidays" choice))))) 171 (list start-year end-year which name))) 172 (message "Computing holidays...") 173 (let* ((holiday-buffer "*Holidays*") 174 (calendar-holidays (if l l calendar-holidays)) 175 (title (or label "Holidays")) 176 (holiday-list nil) 177 (s (calendar-absolute-from-gregorian (list 2 1 y1))) 178 (e (calendar-absolute-from-gregorian (list 11 1 y2))) 179 (d s) 180 (never t) 181 (displayed-month 2) 182 (displayed-year y1)) 183 (while (or never (<= d e)) 184 (setq holiday-list (append holiday-list (calendar-holiday-list))) 185 (setq never nil) 186 (increment-calendar-month displayed-month displayed-year 3) 187 (setq d (calendar-absolute-from-gregorian 188 (list displayed-month 1 displayed-year)))) 189 (save-excursion 190 (set-buffer (get-buffer-create holiday-buffer)) 191 (setq buffer-read-only nil) 192 (calendar-set-mode-line 193 (if (= y1 y2) 194 (format "%s for %s" title y1) 195 (format "%s for %s-%s" title y1 y2))) 196 (erase-buffer) 197 (goto-char (point-min)) 198 (insert 199 (mapconcat 200 '(lambda (x) (concat (calendar-date-string (car x)) 201 ": " (car (cdr x)))) 202 holiday-list "\n")) 203 (goto-char (point-min)) 204 (set-buffer-modified-p nil) 205 (setq buffer-read-only t) 206 (display-buffer holiday-buffer) 207 (message "Computing holidays...done")))) 208 209 210(defun check-calendar-holidays (date) 211 "Check the list of holidays for any that occur on DATE. 212The value returned is a list of strings of relevant holiday descriptions. 213The holidays are those in the list calendar-holidays." 214 (let* ((displayed-month (extract-calendar-month date)) 215 (displayed-year (extract-calendar-year date)) 216 (h (calendar-holiday-list)) 217 (holiday-list)) 218 (while h 219 (if (calendar-date-equal date (car (car h))) 220 (setq holiday-list (append holiday-list (cdr (car h))))) 221 (setq h (cdr h))) 222 holiday-list)) 223 224(defun calendar-cursor-holidays () 225 "Find holidays for the date specified by the cursor in the calendar window." 226 (interactive) 227 (message "Checking holidays...") 228 (let* ((date (calendar-cursor-to-date t)) 229 (date-string (calendar-date-string date)) 230 (holiday-list (check-calendar-holidays date)) 231 (holiday-string (mapconcat 'identity holiday-list "; ")) 232 (msg (format "%s: %s" date-string holiday-string))) 233 (if (not holiday-list) 234 (message "No holidays known for %s" date-string) 235 (if (<= (length msg) (frame-width)) 236 (message "%s" msg) 237 (set-buffer (get-buffer-create holiday-buffer)) 238 (setq buffer-read-only nil) 239 (calendar-set-mode-line date-string) 240 (erase-buffer) 241 (insert (mapconcat 'identity holiday-list "\n")) 242 (goto-char (point-min)) 243 (set-buffer-modified-p nil) 244 (setq buffer-read-only t) 245 (display-buffer holiday-buffer) 246 (message "Checking holidays...done"))))) 247 248(defun mark-calendar-holidays () 249 "Mark notable days in the calendar window." 250 (interactive) 251 (setq mark-holidays-in-calendar t) 252 (message "Marking holidays...") 253 (let ((holiday-list (calendar-holiday-list))) 254 (while holiday-list 255 (mark-visible-calendar-date 256 (car (car holiday-list)) calendar-holiday-marker) 257 (setq holiday-list (cdr holiday-list)))) 258 (message "Marking holidays...done")) 259 260(defun list-calendar-holidays () 261 "Create a buffer containing the holidays for the current calendar window. 262The holidays are those in the list calendar-notable-days. Returns t if any 263holidays are found, nil if not." 264 (interactive) 265 (message "Looking up holidays...") 266 (let ((holiday-list (calendar-holiday-list)) 267 (m1 displayed-month) 268 (y1 displayed-year) 269 (m2 displayed-month) 270 (y2 displayed-year)) 271 (if (not holiday-list) 272 (progn 273 (message "Looking up holidays...none found") 274 nil) 275 (set-buffer (get-buffer-create holiday-buffer)) 276 (setq buffer-read-only nil) 277 (increment-calendar-month m1 y1 -1) 278 (increment-calendar-month m2 y2 1) 279 (calendar-set-mode-line 280 (if (= y1 y2) 281 (format "Notable Dates from %s to %s, %d%%-" 282 (calendar-month-name m1) (calendar-month-name m2) y2) 283 (format "Notable Dates from %s, %d to %s, %d%%-" 284 (calendar-month-name m1) y1 (calendar-month-name m2) y2))) 285 (erase-buffer) 286 (insert 287 (mapconcat 288 '(lambda (x) (concat (calendar-date-string (car x)) 289 ": " (car (cdr x)))) 290 holiday-list "\n")) 291 (goto-char (point-min)) 292 (set-buffer-modified-p nil) 293 (setq buffer-read-only t) 294 (display-buffer holiday-buffer) 295 (message "Looking up holidays...done") 296 t))) 297 298(defun calendar-holiday-list () 299 "Form the list of holidays that occur on dates in the calendar window. 300The holidays are those in the list calendar-holidays." 301 (let ((p calendar-holidays) 302 (holiday-list)) 303 (while p 304 (let* ((holidays 305 (if calendar-debug-sexp 306 (let ((stack-trace-on-error t)) 307 (eval (car p))) 308 (condition-case nil 309 (eval (car p)) 310 (error (beep) 311 (message "Bad holiday list item: %s" (car p)) 312 (sleep-for 2)))))) 313 (if holidays 314 (setq holiday-list (append holidays holiday-list)))) 315 (setq p (cdr p))) 316 (setq holiday-list (sort holiday-list 'calendar-date-compare)))) 317 318;; Below are the functions that calculate the dates of holidays; these 319;; are eval'ed in the function calendar-holiday-list. If you 320;; write other such functions, be sure to imitate the style used below. 321;; Remember that each function must return a list of items of the form 322;; ((month day year) string) of VISIBLE dates in the calendar window. 323 324(defun holiday-fixed (month day string) 325 "Holiday on MONTH, DAY (Gregorian) called STRING. 326If MONTH, DAY is visible, the value returned is the list (((MONTH DAY year) 327STRING)). Returns nil if it is not visible in the current calendar window." 328 (let ((m displayed-month) 329 (y displayed-year)) 330 (increment-calendar-month m y (- 11 month)) 331 (if (> m 9) 332 (list (list (list month day y) string))))) 333 334(defun holiday-float (month dayname n string &optional day) 335 "Holiday on MONTH, DAYNAME (Nth occurrence) called STRING. 336If the Nth DAYNAME in MONTH is visible, the value returned is the list 337\(((MONTH DAY year) STRING)). 338 339If N<0, count backward from the end of MONTH. 340 341An optional parameter DAY means the Nth DAYNAME on or after/before MONTH DAY. 342 343Returns nil if it is not visible in the current calendar window." 344;; This is messy because the holiday may be visible, while the date on which 345;; it is based is not. For example, the first Monday after December 30 may be 346;; visible when January is not. For large values of |n| the problem is more 347;; grotesque. If we didn't have to worry about such cases, we could just use 348 349;; (let ((m displayed-month) 350;; (y displayed-year)) 351;; (increment-calendar-month m y (- 11 month)) 352;; (if (> m 9); month in year y is visible 353;; (list (list (calendar-nth-named-day n dayname month y day) string))))) 354 355;; which is the way the function was originally written. 356 357 (let* ((m1 displayed-month) 358 (y1 displayed-year) 359 (m2 m1) 360 (y2 y1)) 361 (increment-calendar-month m1 y1 -1) 362 (increment-calendar-month m2 y2 1) 363 (let* ((d1; first possible base date for holiday 364 (+ (calendar-nth-named-absday 1 dayname m1 y1) 365 (* -7 n) 366 (if (> n 0) 1 -7))) 367 (d2; last possible base date for holiday 368 (+ (calendar-nth-named-absday -1 dayname m2 y2) 369 (* -7 n) 370 (if (> n 0) 7 -1))) 371 (y1 (extract-calendar-year (calendar-gregorian-from-absolute d1))) 372 (y2 (extract-calendar-year (calendar-gregorian-from-absolute d2))) 373 (y; year of base date 374 (if (or (= y1 y2) (> month 9)) 375 y1 376 y2)) 377 (d; day of base date 378 (or day (if (> n 0) 379 1 380 (calendar-last-day-of-month month y)))) 381 (date; base date for holiday 382 (calendar-absolute-from-gregorian (list month d y)))) 383 (if (and (<= d1 date) (<= date d2)) 384 (list (list (calendar-nth-named-day n dayname month y d) 385 string)))))) 386 387(defun holiday-sexp (sexp string) 388 "Sexp holiday for dates in the calendar window. 389SEXP is an expression in variable `year' evaluates to `date'. 390 391STRING is an expression in `date' that evaluates to the holiday description 392of `date'. 393 394If `date' is visible in the calendar window, the holiday STRING is on that 395date. If date is nil, or if the date is not visible, there is no holiday." 396 (let ((m displayed-month) 397 (y displayed-year)) 398 (increment-calendar-month m y -1) 399 (filter-visible-calendar-holidays 400 (append 401 (let* ((year y) 402 (date (eval sexp)) 403 (string (if date (eval string)))) 404 (list (list date string))) 405 (let* ((year (1+ y)) 406 (date (eval sexp)) 407 (string (if date (eval string)))) 408 (list (list date string))))))) 409 410(defun holiday-advent (&optional n string) 411 "Date of Nth day after advent (named STRING), if visible in calendar window. 412Negative values of N are interpreted as days before advent. 413STRING is used purely for display purposes. The return value has 414the form ((MONTH DAY YEAR) STRING), where the date is that of the 415Nth day before or after advent. 416 417For backwards compatibility, if this function is called with no 418arguments, then it returns the value appropriate for advent itself." 419 ;; Backwards compatibility layer. 420 (if (not n) 421 (holiday-advent 0 "Advent") 422 (let ((year displayed-year) 423 (month displayed-month)) 424 (increment-calendar-month month year -1) 425 (let ((advent (calendar-gregorian-from-absolute 426 (+ n 427 (calendar-dayname-on-or-before 428 0 429 (calendar-absolute-from-gregorian 430 (list 12 3 year))))))) 431 (if (calendar-date-is-visible-p advent) 432 (list (list advent string))))))) 433 434(defun holiday-easter-etc (&optional n string) 435 "Date of Nth day after Easter (named STRING), if visible in calendar window. 436Negative values of N are interpreted as days before Easter. 437STRING is used purely for display purposes. The return value has 438the form ((MONTH DAY YEAR) STRING), where the date is that of the 439Nth day before or after Easter. 440 441For backwards compatibility, if this function is called with no 442arguments, then it returns a list of \"standard\" Easter-related 443holidays (with more entries if `all-christian-calendar-holidays' 444is non-nil)." 445 ;; Backwards compatibility layer. 446 (if (not n) 447 (let (res-list res) 448 (dolist (elem (append 449 (if all-christian-calendar-holidays 450 '((-63 . "Septuagesima Sunday") 451 (-56 . "Sexagesima Sunday") 452 (-49 . "Shrove Sunday") 453 (-48 . "Shrove Monday") 454 (-47 . "Shrove Tuesday") 455 (-14 . "Passion Sunday") 456 (-7 . "Palm Sunday") 457 (-3 . "Maundy Thursday") 458 (35 . "Rogation Sunday") 459 (39 . "Ascension Day") 460 (49 . "Pentecost (Whitsunday)") 461 (50 . "Whitmonday") 462 (56 . "Trinity Sunday") 463 (60 . "Corpus Christi"))) 464 '((0 . "Easter Sunday") 465 (-2 . "Good Friday") 466 (-46 . "Ash Wednesday"))) 467 res-list) 468 ;; Filter out nil (not visible) values. 469 (if (setq res (holiday-easter-etc (car elem) (cdr elem))) 470 (setq res-list (append res res-list))))) 471 (let* ((century (1+ (/ displayed-year 100))) 472 (shifted-epact ;; Age of moon for April 5... 473 (% (+ 14 (* 11 (% displayed-year 19)) ;; ...by Nicaean rule 474 (- ;; ...corrected for the Gregorian century rule 475 (/ (* 3 century) 4)) 476 (/ ;; ...corrected for Metonic cycle inaccuracy. 477 (+ 5 (* 8 century)) 25) 478 (* 30 century)) ;; Keeps value positive. 479 30)) 480 (adjusted-epact ;; Adjust for 29.5 day month. 481 (if (or (zerop shifted-epact) 482 (and (= shifted-epact 1) (< 10 (% displayed-year 19)))) 483 (1+ shifted-epact) 484 shifted-epact)) 485 (paschal-moon ;; Day after the full moon on or after March 21. 486 (- (calendar-absolute-from-gregorian (list 4 19 displayed-year)) 487 adjusted-epact)) 488 (abs-easter (calendar-dayname-on-or-before 0 (+ paschal-moon 7)))) 489 (filter-visible-calendar-holidays 490 (list (list (calendar-gregorian-from-absolute (+ abs-easter n)) 491 string)))))) 492 493(defun holiday-greek-orthodox-easter () 494 "Date of Easter according to the rule of the Council of Nicaea." 495 (let ((m displayed-month) 496 (y displayed-year)) 497 (increment-calendar-month m y 1) 498 (let* ((julian-year 499 (extract-calendar-year 500 (calendar-julian-from-absolute 501 (calendar-absolute-from-gregorian 502 (list m (calendar-last-day-of-month m y) y))))) 503 (shifted-epact ;; Age of moon for April 5. 504 (% (+ 14 505 (* 11 (% julian-year 19))) 506 30)) 507 (paschal-moon ;; Day after full moon on or after March 21. 508 (- (calendar-absolute-from-julian (list 4 19 julian-year)) 509 shifted-epact)) 510 (nicaean-easter;; Sunday following the Paschal moon 511 (calendar-gregorian-from-absolute 512 (calendar-dayname-on-or-before 0 (+ paschal-moon 7))))) 513 (if (calendar-date-is-visible-p nicaean-easter) 514 (list (list nicaean-easter "Pascha (Greek Orthodox Easter)")))))) 515 516(defun filter-visible-calendar-holidays (l) 517 "Return a list of all visible holidays of those on L." 518 (let ((visible) 519 (p l)) 520 (while p 521 (and (car (car p)) 522 (calendar-date-is-visible-p (car (car p))) 523 (setq visible (append (list (car p)) visible))) 524 (setq p (cdr p))) 525 visible)) 526 527(provide 'holidays) 528 529;;; arch-tag: 48eb3117-75a7-4dbe-8fd9-873c3cbb0d37 530;;; holidays.el ends here 531