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502 lines
22 KiB
EmacsLisp
502 lines
22 KiB
EmacsLisp
;;; cal-islam.el --- calendar functions for the Islamic calendar
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;; Copyright (C) 1995, 1997, 2001, 2003 Free Software Foundation, Inc.
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;; Author: Edward M. Reingold <reingold@cs.uiuc.edu>
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;; Keywords: calendar
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;; Human-Keywords: Islamic calendar, calendar, diary
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2, or (at your option)
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;; any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING. If not, write to the
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;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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;; Boston, MA 02111-1307, USA.
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;;; Commentary:
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;; This collection of functions implements the features of calendar.el and
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;; diary.el that deal with the Islamic calendar.
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;; Technical details of all the calendrical calculations can be found in
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;; ``Calendrical Calculations: The Millennium Edition'' by Edward M. Reingold
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;; and Nachum Dershowitz, Cambridge University Press (2001).
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;; Comments, corrections, and improvements should be sent to
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;; Edward M. Reingold Department of Computer Science
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;; (217) 333-6733 University of Illinois at Urbana-Champaign
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;; reingold@cs.uiuc.edu 1304 West Springfield Avenue
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;; Urbana, Illinois 61801
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;;; Code:
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(defvar displayed-month)
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(defvar displayed-year)
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(require 'cal-julian)
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(defvar calendar-islamic-month-name-array
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["Muharram" "Safar" "Rabi I" "Rabi II" "Jumada I" "Jumada II"
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"Rajab" "Sha'ban" "Ramadan" "Shawwal" "Dhu al-Qada" "Dhu al-Hijjah"]
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"Array of strings giving the names of the Islamic months.")
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(defvar calendar-islamic-epoch (calendar-absolute-from-julian '(7 16 622))
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"Absolute date of start of Islamic calendar = August 29, 284 A.D. (Julian).")
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(defun islamic-calendar-leap-year-p (year)
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"Returns t if YEAR is a leap year on the Islamic calendar."
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(memq (% year 30)
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(list 2 5 7 10 13 16 18 21 24 26 29)))
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(defun islamic-calendar-last-day-of-month (month year)
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"The last day in MONTH during YEAR on the Islamic calendar."
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(cond
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((memq month (list 1 3 5 7 9 11)) 30)
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((memq month (list 2 4 6 8 10)) 29)
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(t (if (islamic-calendar-leap-year-p year) 30 29))))
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(defun islamic-calendar-day-number (date)
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"Return the day number within the year of the Islamic date DATE."
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(let* ((month (extract-calendar-month date))
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(day (extract-calendar-day date)))
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(+ (* 30 (/ month 2))
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(* 29 (/ (1- month) 2))
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day)))
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(defun calendar-absolute-from-islamic (date)
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"Absolute date of Islamic DATE.
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The absolute date is the number of days elapsed since the (imaginary)
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Gregorian date Sunday, December 31, 1 BC."
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(let* ((month (extract-calendar-month date))
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(day (extract-calendar-day date))
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(year (extract-calendar-year date))
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(y (% year 30))
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(leap-years-in-cycle
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(cond
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((< y 3) 0) ((< y 6) 1) ((< y 8) 2) ((< y 11) 3) ((< y 14) 4)
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((< y 17) 5) ((< y 19) 6) ((< y 22) 7) ((< y 25) 8) ((< y 27) 9)
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(t 10))))
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(+ (islamic-calendar-day-number date);; days so far this year
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(* (1- year) 354) ;; days in all non-leap years
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(* 11 (/ year 30)) ;; leap days in complete cycles
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leap-years-in-cycle ;; leap days this cycle
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(1- calendar-islamic-epoch)))) ;; days before start of calendar
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(defun calendar-islamic-from-absolute (date)
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"Compute the Islamic date (month day year) corresponding to absolute DATE.
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The absolute date is the number of days elapsed since the (imaginary)
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Gregorian date Sunday, December 31, 1 BC."
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(if (< date calendar-islamic-epoch)
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(list 0 0 0);; pre-Islamic date
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(let* ((approx (/ (- date calendar-islamic-epoch)
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355));; Approximation from below.
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(year ;; Search forward from the approximation.
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(+ approx
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(calendar-sum y approx
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(>= date (calendar-absolute-from-islamic
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(list 1 1 (1+ y))))
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1)))
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(month ;; Search forward from Muharram.
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(1+ (calendar-sum m 1
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(> date
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(calendar-absolute-from-islamic
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(list m
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(islamic-calendar-last-day-of-month
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m year)
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year)))
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1)))
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(day ;; Calculate the day by subtraction.
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(- date
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(1- (calendar-absolute-from-islamic (list month 1 year))))))
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(list month day year))))
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(defun calendar-islamic-date-string (&optional date)
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"String of Islamic date before sunset of Gregorian DATE.
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Returns the empty string if DATE is pre-Islamic.
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Defaults to today's date if DATE is not given.
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Driven by the variable `calendar-date-display-form'."
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(let ((calendar-month-name-array calendar-islamic-month-name-array)
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(islamic-date (calendar-islamic-from-absolute
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(calendar-absolute-from-gregorian
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(or date (calendar-current-date))))))
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(if (< (extract-calendar-year islamic-date) 1)
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""
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(calendar-date-string islamic-date nil t))))
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(defun calendar-print-islamic-date ()
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"Show the Islamic calendar equivalent of the date under the cursor."
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(interactive)
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(let ((i (calendar-islamic-date-string (calendar-cursor-to-date t))))
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(if (string-equal i "")
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(message "Date is pre-Islamic")
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(message "Islamic date (until sunset): %s" i))))
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(defun calendar-goto-islamic-date (date &optional noecho)
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"Move cursor to Islamic DATE; echo Islamic date unless NOECHO is t."
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(interactive
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(let* ((today (calendar-current-date))
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(year (calendar-read
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"Islamic calendar year (>0): "
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'(lambda (x) (> x 0))
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(int-to-string
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(extract-calendar-year
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(calendar-islamic-from-absolute
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(calendar-absolute-from-gregorian today))))))
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(month-array calendar-islamic-month-name-array)
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(completion-ignore-case t)
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(month (cdr (assoc-string
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(completing-read
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"Islamic calendar month name: "
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(mapcar 'list (append month-array nil))
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nil t)
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(calendar-make-alist month-array 1) t)))
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(last (islamic-calendar-last-day-of-month month year))
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(day (calendar-read
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(format "Islamic calendar day (1-%d): " last)
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'(lambda (x) (and (< 0 x) (<= x last))))))
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(list (list month day year))))
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(calendar-goto-date (calendar-gregorian-from-absolute
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(calendar-absolute-from-islamic date)))
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(or noecho (calendar-print-islamic-date)))
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(defun diary-islamic-date ()
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"Islamic calendar equivalent of date diary entry."
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(let ((i (calendar-islamic-date-string date)))
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(if (string-equal i "")
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"Date is pre-Islamic"
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(format "Islamic date (until sunset): %s" i))))
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(defun holiday-islamic (month day string)
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"Holiday on MONTH, DAY (Islamic) called STRING.
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If MONTH, DAY (Islamic) is visible, the value returned is corresponding
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Gregorian date in the form of the list (((month day year) STRING)). Returns
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nil if it is not visible in the current calendar window."
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(let* ((islamic-date (calendar-islamic-from-absolute
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(calendar-absolute-from-gregorian
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(list displayed-month 15 displayed-year))))
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(m (extract-calendar-month islamic-date))
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(y (extract-calendar-year islamic-date))
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(date))
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(if (< m 1)
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nil;; Islamic calendar doesn't apply.
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(increment-calendar-month m y (- 10 month))
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(if (> m 7);; Islamic date might be visible
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(let ((date (calendar-gregorian-from-absolute
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(calendar-absolute-from-islamic (list month day y)))))
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(if (calendar-date-is-visible-p date)
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(list (list date string))))))))
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(defun list-islamic-diary-entries ()
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"Add any Islamic date entries from the diary file to `diary-entries-list'.
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Islamic date diary entries must be prefaced by an `islamic-diary-entry-symbol'
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\(normally an `I'). The same diary date forms govern the style of the Islamic
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calendar entries, except that the Islamic month names must be spelled in full.
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The Islamic months are numbered from 1 to 12 with Muharram being 1 and 12 being
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Dhu al-Hijjah. If an Islamic date diary entry begins with a
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`diary-nonmarking-symbol', the entry will appear in the diary listing, but will
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not be marked in the calendar. This function is provided for use with the
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`nongregorian-diary-listing-hook'."
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(if (< 0 number)
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(let ((buffer-read-only nil)
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(diary-modified (buffer-modified-p))
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(gdate original-date)
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(mark (regexp-quote diary-nonmarking-symbol)))
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(calendar-for-loop i from 1 to number do
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(let* ((d diary-date-forms)
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(idate (calendar-islamic-from-absolute
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(calendar-absolute-from-gregorian gdate)))
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(month (extract-calendar-month idate))
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(day (extract-calendar-day idate))
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(year (extract-calendar-year idate)))
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(while d
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(let*
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((date-form (if (equal (car (car d)) 'backup)
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(cdr (car d))
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(car d)))
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(backup (equal (car (car d)) 'backup))
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(dayname
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(format "%s\\|%s\\.?"
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(calendar-day-name gdate)
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(calendar-day-name gdate 'abbrev)))
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(calendar-month-name-array
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calendar-islamic-month-name-array)
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(monthname
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(concat
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"\\*\\|"
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(calendar-month-name month)))
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(month (concat "\\*\\|0*" (int-to-string month)))
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(day (concat "\\*\\|0*" (int-to-string day)))
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(year
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(concat
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"\\*\\|0*" (int-to-string year)
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(if abbreviated-calendar-year
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(concat "\\|" (int-to-string (% year 100)))
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"")))
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(regexp
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(concat
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"\\(\\`\\|\^M\\|\n\\)" mark "?"
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(regexp-quote islamic-diary-entry-symbol)
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"\\("
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(mapconcat 'eval date-form "\\)\\(")
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"\\)"))
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(case-fold-search t))
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(goto-char (point-min))
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(while (re-search-forward regexp nil t)
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(if backup (re-search-backward "\\<" nil t))
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(if (and (or (char-equal (preceding-char) ?\^M)
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(char-equal (preceding-char) ?\n))
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(not (looking-at " \\|\^I")))
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;; Diary entry that consists only of date.
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(backward-char 1)
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;; Found a nonempty diary entry--make it visible and
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;; add it to the list.
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(let ((entry-start (point))
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(date-start))
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(re-search-backward "\^M\\|\n\\|\\`")
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(setq date-start (point))
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(re-search-forward "\^M\\|\n" nil t 2)
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(while (looking-at " \\|\^I")
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(re-search-forward "\^M\\|\n" nil t))
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(backward-char 1)
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(subst-char-in-region date-start (point) ?\^M ?\n t)
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(add-to-diary-list
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gdate
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(buffer-substring-no-properties entry-start (point))
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(buffer-substring-no-properties
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(1+ date-start) (1- entry-start))
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(copy-marker entry-start))))))
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(setq d (cdr d))))
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(setq gdate
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(calendar-gregorian-from-absolute
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(1+ (calendar-absolute-from-gregorian gdate)))))
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(set-buffer-modified-p diary-modified))
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(goto-char (point-min))))
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(defun mark-islamic-diary-entries ()
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"Mark days in the calendar window that have Islamic date diary entries.
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Each entry in diary-file (or included files) visible in the calendar window
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is marked. Islamic date entries are prefaced by a islamic-diary-entry-symbol
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\(normally an `I'). The same diary-date-forms govern the style of the Islamic
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calendar entries, except that the Islamic month names must be spelled in full.
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The Islamic months are numbered from 1 to 12 with Muharram being 1 and 12 being
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Dhu al-Hijjah. Islamic date diary entries that begin with a
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diary-nonmarking-symbol will not be marked in the calendar. This function is
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provided for use as part of the nongregorian-diary-marking-hook."
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(let ((d diary-date-forms))
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(while d
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(let*
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((date-form (if (equal (car (car d)) 'backup)
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(cdr (car d))
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(car d)));; ignore 'backup directive
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(dayname (diary-name-pattern calendar-day-name-array
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calendar-day-abbrev-array))
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(monthname
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(format "%s\\|\\*"
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(diary-name-pattern calendar-islamic-month-name-array)))
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(month "[0-9]+\\|\\*")
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(day "[0-9]+\\|\\*")
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(year "[0-9]+\\|\\*")
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(l (length date-form))
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(d-name-pos (- l (length (memq 'dayname date-form))))
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(d-name-pos (if (/= l d-name-pos) (+ 2 d-name-pos)))
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(m-name-pos (- l (length (memq 'monthname date-form))))
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(m-name-pos (if (/= l m-name-pos) (+ 2 m-name-pos)))
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(d-pos (- l (length (memq 'day date-form))))
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(d-pos (if (/= l d-pos) (+ 2 d-pos)))
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(m-pos (- l (length (memq 'month date-form))))
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(m-pos (if (/= l m-pos) (+ 2 m-pos)))
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(y-pos (- l (length (memq 'year date-form))))
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(y-pos (if (/= l y-pos) (+ 2 y-pos)))
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(regexp
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(concat
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"\\(\\`\\|\^M\\|\n\\)"
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(regexp-quote islamic-diary-entry-symbol)
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"\\("
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(mapconcat 'eval date-form "\\)\\(")
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"\\)"))
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(case-fold-search t))
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(goto-char (point-min))
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(while (re-search-forward regexp nil t)
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(let* ((dd-name
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(if d-name-pos
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(buffer-substring
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(match-beginning d-name-pos)
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(match-end d-name-pos))))
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(mm-name
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(if m-name-pos
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(buffer-substring
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(match-beginning m-name-pos)
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(match-end m-name-pos))))
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(mm (string-to-number
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(if m-pos
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(buffer-substring
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(match-beginning m-pos)
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(match-end m-pos))
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"")))
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(dd (string-to-number
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(if d-pos
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(buffer-substring
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(match-beginning d-pos)
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(match-end d-pos))
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"")))
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(y-str (if y-pos
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(buffer-substring
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(match-beginning y-pos)
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(match-end y-pos))))
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(yy (if (not y-str)
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0
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(if (and (= (length y-str) 2)
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abbreviated-calendar-year)
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(let* ((current-y
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(extract-calendar-year
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(calendar-islamic-from-absolute
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(calendar-absolute-from-gregorian
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(calendar-current-date)))))
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(y (+ (string-to-number y-str)
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(* 100 (/ current-y 100)))))
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(if (> (- y current-y) 50)
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(- y 100)
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(if (> (- current-y y) 50)
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(+ y 100)
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y)))
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(string-to-number y-str)))))
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(if dd-name
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(mark-calendar-days-named
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(cdr (assoc-string dd-name
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(calendar-make-alist
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calendar-day-name-array
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0 nil calendar-day-abbrev-array) t)))
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(if mm-name
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(setq mm (if (string-equal mm-name "*") 0
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(cdr (assoc-string
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mm-name
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(calendar-make-alist
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calendar-islamic-month-name-array) t)))))
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(mark-islamic-calendar-date-pattern mm dd yy)))))
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(setq d (cdr d)))))
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(defun mark-islamic-calendar-date-pattern (month day year)
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"Mark dates in calendar window that conform to Islamic date MONTH/DAY/YEAR.
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A value of 0 in any position is a wildcard."
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(save-excursion
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(set-buffer calendar-buffer)
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(if (and (/= 0 month) (/= 0 day))
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(if (/= 0 year)
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;; Fully specified Islamic date.
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(let ((date (calendar-gregorian-from-absolute
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(calendar-absolute-from-islamic
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(list month day year)))))
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(if (calendar-date-is-visible-p date)
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(mark-visible-calendar-date date)))
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;; Month and day in any year--this taken from the holiday stuff.
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(let* ((islamic-date (calendar-islamic-from-absolute
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(calendar-absolute-from-gregorian
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(list displayed-month 15 displayed-year))))
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(m (extract-calendar-month islamic-date))
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(y (extract-calendar-year islamic-date))
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(date))
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(if (< m 1)
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nil;; Islamic calendar doesn't apply.
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(increment-calendar-month m y (- 10 month))
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(if (> m 7);; Islamic date might be visible
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(let ((date (calendar-gregorian-from-absolute
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(calendar-absolute-from-islamic
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(list month day y)))))
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(if (calendar-date-is-visible-p date)
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(mark-visible-calendar-date date)))))))
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;; Not one of the simple cases--check all visible dates for match.
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;; Actually, the following code takes care of ALL of the cases, but
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;; it's much too slow to be used for the simple (common) cases.
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(let ((m displayed-month)
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(y displayed-year)
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(first-date)
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(last-date))
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(increment-calendar-month m y -1)
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(setq first-date
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(calendar-absolute-from-gregorian
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(list m 1 y)))
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(increment-calendar-month m y 2)
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(setq last-date
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(calendar-absolute-from-gregorian
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(list m (calendar-last-day-of-month m y) y)))
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(calendar-for-loop date from first-date to last-date do
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(let* ((i-date (calendar-islamic-from-absolute date))
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(i-month (extract-calendar-month i-date))
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(i-day (extract-calendar-day i-date))
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(i-year (extract-calendar-year i-date)))
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(and (or (zerop month)
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(= month i-month))
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(or (zerop day)
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(= day i-day))
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(or (zerop year)
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(= year i-year))
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(mark-visible-calendar-date
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(calendar-gregorian-from-absolute date)))))))))
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(defun insert-islamic-diary-entry (arg)
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"Insert a diary entry.
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For the Islamic date corresponding to the date indicated by point.
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|
Prefix arg will make the entry nonmarking."
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|
(interactive "P")
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(let* ((calendar-month-name-array calendar-islamic-month-name-array))
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|
(make-diary-entry
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|
(concat
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islamic-diary-entry-symbol
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|
(calendar-date-string
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|
(calendar-islamic-from-absolute
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|
(calendar-absolute-from-gregorian
|
|
(calendar-cursor-to-date t)))
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|
nil t))
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|
arg)))
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|
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(defun insert-monthly-islamic-diary-entry (arg)
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|
"Insert a monthly diary entry.
|
|
For the day of the Islamic month corresponding to the date indicated by point.
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|
Prefix arg will make the entry nonmarking."
|
|
(interactive "P")
|
|
(let* ((calendar-date-display-form
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|
(if european-calendar-style '(day " * ") '("* " day )))
|
|
(calendar-month-name-array calendar-islamic-month-name-array))
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|
(make-diary-entry
|
|
(concat
|
|
islamic-diary-entry-symbol
|
|
(calendar-date-string
|
|
(calendar-islamic-from-absolute
|
|
(calendar-absolute-from-gregorian
|
|
(calendar-cursor-to-date t)))))
|
|
arg)))
|
|
|
|
(defun insert-yearly-islamic-diary-entry (arg)
|
|
"Insert an annual diary entry.
|
|
For the day of the Islamic year corresponding to the date indicated by point.
|
|
Prefix arg will make the entry nonmarking."
|
|
(interactive "P")
|
|
(let* ((calendar-date-display-form
|
|
(if european-calendar-style
|
|
'(day " " monthname)
|
|
'(monthname " " day)))
|
|
(calendar-month-name-array calendar-islamic-month-name-array))
|
|
(make-diary-entry
|
|
(concat
|
|
islamic-diary-entry-symbol
|
|
(calendar-date-string
|
|
(calendar-islamic-from-absolute
|
|
(calendar-absolute-from-gregorian
|
|
(calendar-cursor-to-date t)))))
|
|
arg)))
|
|
|
|
(provide 'cal-islam)
|
|
|
|
;;; arch-tag: a951b6c1-6f47-48d5-bac3-1b505cd719f7
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|
;;; cal-islam.el ends here
|