;;; cal-hebrew.el --- calendar functions for the Hebrew calendar.

;; Copyright (C) 1995 Free Software Foundation, Inc.

;; Author: Nachum Dershowitz <nachum@cs.uiuc.edu>
;;      Edward M. Reingold <reingold@cs.uiuc.edu>
;; Keywords: calendar
;; Human-Keywords: Hebrew calendar, calendar, diary

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; 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.

;;; Commentary:

;; This collection of functions implements the features of calendar.el and
;; diary.el that deal with the Hebrew calendar.

;; 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:

(require 'calendar)

(defun calendar-hebrew-from-absolute (date)
  "Compute the Hebrew date (month day year) corresponding to absolute DATE.
The absolute date is the number of days elapsed since the (imaginary)
Gregorian date Sunday, December 31, 1 BC."
  (let* ((greg-date (calendar-gregorian-from-absolute date))
         (month (aref [9 10 11 12 1 2 3 4 7 7 7 8]
                 (1- (extract-calendar-month greg-date))))
         (day)
         (year (+ 3760 (extract-calendar-year greg-date))))
    (while (>= date (calendar-absolute-from-hebrew (list 7 1 (1+ year))))
        (setq year (1+ year)))
    (let ((length (hebrew-calendar-last-month-of-year year)))
      (while (> date
                (calendar-absolute-from-hebrew
                 (list month
                       (hebrew-calendar-last-day-of-month month year)
                       year)))
        (setq month (1+ (% month length)))))
    (setq day (1+
               (- date (calendar-absolute-from-hebrew (list month 1 year)))))
    (list month day year)))

(defun hebrew-calendar-leap-year-p (year)
  "t if YEAR is a Hebrew calendar leap year."
  (< (% (1+ (* 7 year)) 19) 7))

(defun hebrew-calendar-last-month-of-year (year)
  "The last month of the Hebrew calendar YEAR."
  (if (hebrew-calendar-leap-year-p year)
      13
    12))

(defun hebrew-calendar-last-day-of-month (month year)
  "The last day of MONTH in YEAR."
  (if (or (memq month (list 2 4 6 10 13))
          (and (= month 12) (not (hebrew-calendar-leap-year-p year)))
          (and (= month 8) (not (hebrew-calendar-long-heshvan-p year)))
          (and (= month 9) (hebrew-calendar-short-kislev-p year)))
      29
    30))

(defun hebrew-calendar-elapsed-days (year)
  "Days from Sun. prior to start of Hebrew calendar to mean conjunction of Tishri of Hebrew YEAR."
  (let* ((months-elapsed
          (+ (* 235 (/ (1- year) 19));; Months in complete cycles so far.
             (* 12 (% (1- year) 19))      ;; Regular months in this cycle
             (/ (1+ (* 7 (% (1- year) 19))) 19)));; Leap months this cycle
         (parts-elapsed (+ 204 (* 793 (% months-elapsed 1080))))
         (hours-elapsed (+ 5
                           (* 12 months-elapsed)
                           (* 793 (/ months-elapsed 1080))
                           (/ parts-elapsed 1080)))
         (parts                                  ;; Conjunction parts
          (+ (* 1080 (% hours-elapsed 24)) (% parts-elapsed 1080)))
         (day                                    ;; Conjunction day
          (+ 1 (* 29 months-elapsed) (/ hours-elapsed 24)))
         (alternative-day
          (if (or (>= parts 19440)    ;; If the new moon is at or after midday,
                  (and (= (% day 7) 2);; ...or is on a Tuesday...
                       (>= parts 9924)  ;;    at 9 hours, 204 parts or later...
                       (not (hebrew-calendar-leap-year-p year)));; of a
                                                                ;; common year,
                  (and (= (% day 7) 1);; ...or is on a Monday...
                       (>= parts 16789) ;;   at 15 hours, 589 parts or later...
                       (hebrew-calendar-leap-year-p (1- year))));; at the end
                                                     ;; of a leap year
       ;; Then postpone Rosh HaShanah one day
              (1+ day)
       ;; Else
            day)))
    (if ;; If Rosh HaShanah would occur on Sunday, Wednesday, or Friday
        (memq (% alternative-day 7) (list 0 3 5))
  ;; Then postpone it one (more) day and return        
        (1+ alternative-day)
  ;; Else return        
      alternative-day)))

(defun hebrew-calendar-days-in-year (year)
  "Number of days in Hebrew YEAR."
  (- (hebrew-calendar-elapsed-days (1+ year))
     (hebrew-calendar-elapsed-days year)))

(defun hebrew-calendar-long-heshvan-p (year)
  "t if Heshvan is long in Hebrew YEAR."
  (= (% (hebrew-calendar-days-in-year year) 10) 5))

(defun hebrew-calendar-short-kislev-p (year)
  "t if Kislev is short in Hebrew YEAR."
  (= (% (hebrew-calendar-days-in-year year) 10) 3))

(defun calendar-absolute-from-hebrew (date)
  "Absolute date of Hebrew DATE.
The absolute date is the number of days elapsed since the (imaginary)
Gregorian date Sunday, December 31, 1 BC."
  (let* ((month (extract-calendar-month date))
         (day (extract-calendar-day date))
         (year (extract-calendar-year date)))
    (+ day                            ;; Days so far this month.
       (if (< month 7);; before Tishri
     ;; Then add days in prior months this year before and after Nisan
           (+ (calendar-sum
               m 7 (<= m (hebrew-calendar-last-month-of-year year))
               (hebrew-calendar-last-day-of-month m year))
              (calendar-sum
               m 1 (< m month)
               (hebrew-calendar-last-day-of-month m year)))
     ;; Else add days in prior months this year
         (calendar-sum
          m 7 (< m month)
          (hebrew-calendar-last-day-of-month m year)))
    (hebrew-calendar-elapsed-days year);; Days in prior years.
    -1373429)))                        ;; Days elapsed before absolute date 1.

(defvar calendar-hebrew-month-name-array-common-year
  ["Nisan" "Iyar" "Sivan" "Tammuz" "Av" "Elul" "Tishri"
   "Heshvan" "Kislev" "Teveth" "Shevat" "Adar"])

(defvar calendar-hebrew-month-name-array-leap-year
  ["Nisan" "Iyar" "Sivan" "Tammuz" "Av" "Elul" "Tishri"
   "Heshvan" "Kislev" "Teveth" "Shevat" "Adar I" "Adar II"])

(defun calendar-hebrew-date-string (&optional date)
  "String of Hebrew date before sunset of Gregorian DATE.
Defaults to today's date if DATE is not given.
Driven by the variable `calendar-date-display-form'."
  (let* ((hebrew-date (calendar-hebrew-from-absolute
                       (calendar-absolute-from-gregorian
                        (or date (calendar-current-date)))))
         (calendar-month-name-array
          (if (hebrew-calendar-leap-year-p (extract-calendar-year hebrew-date))
              calendar-hebrew-month-name-array-leap-year
            calendar-hebrew-month-name-array-common-year)))
    (calendar-date-string hebrew-date nil t)))

(defun calendar-print-hebrew-date ()
  "Show the Hebrew calendar equivalent of the date under the cursor."
  (interactive)
  (message "Hebrew date (until sunset): %s"
           (calendar-hebrew-date-string (calendar-cursor-to-date t))))

(defun hebrew-calendar-yahrzeit (death-date year)
  "Absolute date of the anniversary of Hebrew DEATH-DATE in Hebrew YEAR."
  (let* ((death-day (extract-calendar-day death-date))
         (death-month (extract-calendar-month death-date))
         (death-year (extract-calendar-year death-date)))
    (cond
     ;; If it's Heshvan 30 it depends on the first anniversary; if
     ;; that was not Heshvan 30, use the day before Kislev 1.
     ((and (= death-month 8)
           (= death-day 30)
           (not (hebrew-calendar-long-heshvan-p (1+ death-year))))
      (1- (calendar-absolute-from-hebrew (list 9 1 year))))
     ;; If it's Kislev 30 it depends on the first anniversary; if
     ;; that was not Kislev 30, use the day before Teveth 1.
     ((and (= death-month 9)
           (= death-day 30)
           (hebrew-calendar-short-kislev-p (1+ death-year)))
      (1- (calendar-absolute-from-hebrew (list 10 1 year))))
     ;; If it's Adar II, use the same day in last month of
     ;; year (Adar or Adar II).
     ((= death-month 13)
      (calendar-absolute-from-hebrew
       (list (hebrew-calendar-last-month-of-year year) death-day year)))
     ;; If it's the 30th in Adar I and year is not a leap year
     ;; (so Adar has only 29 days), use the last day in Shevat.
     ((and (= death-day 30)
           (= death-month 12)
           (not (hebrew-calendar-leap-year-p year)))
      (calendar-absolute-from-hebrew (list 11 30 year)))
     ;; In all other cases, use the normal anniversary of the date of death.
     (t (calendar-absolute-from-hebrew
         (list death-month death-day year))))))

(defun calendar-goto-hebrew-date (date &optional noecho)
  "Move cursor to Hebrew DATE; echo Hebrew date unless NOECHO is t."
  (interactive
   (let* ((today (calendar-current-date))
          (year (calendar-read
                 "Hebrew calendar year (>3760): "
                 '(lambda (x) (> x 3760))
                 (int-to-string
                  (extract-calendar-year
                   (calendar-hebrew-from-absolute
                    (calendar-absolute-from-gregorian today))))))
          (month-array (if (hebrew-calendar-leap-year-p year)
                           calendar-hebrew-month-name-array-leap-year
                         calendar-hebrew-month-name-array-common-year))
          (completion-ignore-case t)
          (month (cdr (assoc
                       (capitalize
                        (completing-read
                         "Hebrew calendar month name: "
                         (mapcar 'list (append month-array nil))
                         (if (= year 3761)
                             '(lambda (x)
                                (let ((m (cdr
                                          (assoc
                                           (car x)
                                           (calendar-make-alist
                                            month-array)))))
                                  (< 0
                                     (calendar-absolute-from-hebrew
                                      (list m
                                            (hebrew-calendar-last-day-of-month
                                             m year)
                                            year))))))
                                 
                         t))
                       (calendar-make-alist month-array 1 'capitalize))))
          (last (hebrew-calendar-last-day-of-month month year))
          (first (if (and (= year 3761) (= month 10))
                     18 1))
          (day (calendar-read
                (format "Hebrew calendar day (%d-%d): "
                        first last)
                '(lambda (x) (and (<= first x) (<= x last))))))
     (list (list month day year))))
  (calendar-goto-date (calendar-gregorian-from-absolute
                       (calendar-absolute-from-hebrew date)))
  (or noecho (calendar-print-hebrew-date)))

(defun holiday-hebrew (month day string)
  "Holiday on MONTH, DAY (Hebrew) called STRING.
If MONTH, DAY (Hebrew) is visible, the value returned is corresponding
Gregorian date in the form of the list (((month day year) STRING)).  Returns
nil if it is not visible in the current calendar window."
  (if (memq displayed-month;;  This test is only to speed things up a bit;
            (list          ;;  it works fine without the test too.
             (if (< 11 month) (- month 11) (+ month 1))
             (if (< 10 month) (- month 10) (+ month 2))
             (if (<  9 month) (- month  9) (+ month 3))
             (if (<  8 month) (- month  8) (+ month 4))
             (if (<  7 month) (- month  7) (+ month 5))))
      (let ((m1 displayed-month)
            (y1 displayed-year)
            (m2 displayed-month)
            (y2 displayed-year)
            (year))
        (increment-calendar-month m1 y1 -1)
        (increment-calendar-month m2 y2 1)
        (let* ((start-date (calendar-absolute-from-gregorian
                            (list m1 1 y1)))
               (end-date (calendar-absolute-from-gregorian
                          (list m2 (calendar-last-day-of-month m2 y2) y2)))
               (hebrew-start (calendar-hebrew-from-absolute start-date))
               (hebrew-end (calendar-hebrew-from-absolute end-date))
               (hebrew-y1 (extract-calendar-year hebrew-start))
               (hebrew-y2 (extract-calendar-year hebrew-end)))
          (setq year (if (< 6 month) hebrew-y2 hebrew-y1))
          (let ((date (calendar-gregorian-from-absolute
                       (calendar-absolute-from-hebrew
                        (list month day year)))))
            (if (calendar-date-is-visible-p date)
                (list (list date string))))))))

(defun holiday-rosh-hashanah-etc ()
  "List of dates related to Rosh Hashanah, as visible in calendar window."
  (if (or (< displayed-month 8)
          (> displayed-month 11))
      nil;; None of the dates is visible
    (let* ((abs-r-h (calendar-absolute-from-hebrew
                      (list 7 1 (+ displayed-year 3761))))
            (mandatory
             (list
              (list (calendar-gregorian-from-absolute abs-r-h)
                    (format "Rosh HaShanah %d" (+ 3761 displayed-year)))
              (list (calendar-gregorian-from-absolute (+ abs-r-h 9))
                    "Yom Kippur")
              (list (calendar-gregorian-from-absolute (+ abs-r-h 14))
                    "Sukkot")
              (list (calendar-gregorian-from-absolute (+ abs-r-h 21))
                    "Shemini Atzeret")
              (list (calendar-gregorian-from-absolute (+ abs-r-h 22))
                    "Simchat Torah")))
           (optional
            (list 
             (list (calendar-gregorian-from-absolute
                    (calendar-dayname-on-or-before 6 (- abs-r-h 4)))
                   "Selichot (night)")
             (list (calendar-gregorian-from-absolute (1- abs-r-h))
                   "Erev Rosh HaShanah")
             (list (calendar-gregorian-from-absolute (1+ abs-r-h))
                   "Rosh HaShanah (second day)")
             (list (calendar-gregorian-from-absolute
                    (if (= (% abs-r-h 7) 4) (+ abs-r-h 3) (+ abs-r-h 2)))
                   "Tzom Gedaliah")
             (list (calendar-gregorian-from-absolute
                    (calendar-dayname-on-or-before 6 (+ 7 abs-r-h)))
                   "Shabbat Shuvah")
             (list (calendar-gregorian-from-absolute (+ abs-r-h 8))
                   "Erev Yom Kippur")
             (list (calendar-gregorian-from-absolute (+ abs-r-h 13))
                   "Erev Sukkot")
             (list (calendar-gregorian-from-absolute (+ abs-r-h 15))
                   "Sukkot (second day)")
             (list (calendar-gregorian-from-absolute (+ abs-r-h 16))
                   "Hol Hamoed Sukkot (first day)")
             (list (calendar-gregorian-from-absolute (+ abs-r-h 17))
                   "Hol Hamoed Sukkot (second day)")
             (list (calendar-gregorian-from-absolute (+ abs-r-h 18))
                   "Hol Hamoed Sukkot (third day)")
             (list (calendar-gregorian-from-absolute (+ abs-r-h 19))
                   "Hol Hamoed Sukkot (fourth day)")
             (list (calendar-gregorian-from-absolute (+ abs-r-h 20))
                   "Hoshannah Rabbah")))
            (output-list
             (filter-visible-calendar-holidays mandatory)))
      (if all-hebrew-calendar-holidays
          (setq output-list
                (append 
                 (filter-visible-calendar-holidays optional)
                 output-list)))
      output-list)))

(defun holiday-hanukkah ()
  "List of dates related to Hanukkah, as visible in calendar window."
    (if (memq displayed-month;;  This test is only to speed things up a bit;
              '(10 11 12 1 2));; it works fine without the test too.
        (let ((m displayed-month)
              (y displayed-year))
          (increment-calendar-month m y 1)
          (let* ((h-y (extract-calendar-year
                         (calendar-hebrew-from-absolute
                          (calendar-absolute-from-gregorian
                           (list m (calendar-last-day-of-month m y) y)))))
                 (abs-h (calendar-absolute-from-hebrew (list 9 25 h-y))))
            (filter-visible-calendar-holidays
             (list
              (list (calendar-gregorian-from-absolute (1- abs-h))
                    "Erev Hanukkah")
              (list (calendar-gregorian-from-absolute abs-h)
                    "Hanukkah (first day)")
              (list (calendar-gregorian-from-absolute (1+ abs-h))
                    "Hanukkah (second day)")
              (list (calendar-gregorian-from-absolute (+ abs-h 2))
                    "Hanukkah (third day)")
              (list (calendar-gregorian-from-absolute (+ abs-h 3))
                    "Hanukkah (fourth day)")
              (list (calendar-gregorian-from-absolute (+ abs-h 4))
                    "Hanukkah (fifth day)")
              (list (calendar-gregorian-from-absolute (+ abs-h 5))
                    "Hanukkah (sixth day)")
              (list (calendar-gregorian-from-absolute (+ abs-h 6))
                    "Hanukkah (seventh day)")
              (list (calendar-gregorian-from-absolute (+ abs-h 7))
                    "Hanukkah (eighth day)")))))))

(defun holiday-passover-etc ()
  "List of dates related to Passover, as visible in calendar window."
 (if (< 7 displayed-month)
      nil;; None of the dates is visible
    (let* ((abs-p (calendar-absolute-from-hebrew
                      (list 1 15 (+ displayed-year 3760))))
           (mandatory
            (list
             (list (calendar-gregorian-from-absolute abs-p)
                   "Passover")
             (list (calendar-gregorian-from-absolute (+ abs-p 50))
                   "Shavuot")))
           (optional
            (list 
             (list (calendar-gregorian-from-absolute
                    (calendar-dayname-on-or-before 6 (- abs-p 43)))
                   "Shabbat Shekalim")
             (list (calendar-gregorian-from-absolute
                    (calendar-dayname-on-or-before 6 (- abs-p 30)))
                   "Shabbat Zachor")
             (list (calendar-gregorian-from-absolute
                    (if (= (% abs-p 7) 2) (- abs-p 33) (- abs-p 31)))
                   "Fast of Esther")
             (list (calendar-gregorian-from-absolute (- abs-p 31))
                   "Erev Purim")
             (list (calendar-gregorian-from-absolute (- abs-p 30))
                   "Purim")
             (list (calendar-gregorian-from-absolute
                    (if (zerop (% abs-p 7)) (- abs-p 28) (- abs-p 29)))
                   "Shushan Purim")
             (list (calendar-gregorian-from-absolute
                    (- (calendar-dayname-on-or-before 6 (- abs-p 14)) 7))
                   "Shabbat Parah")
             (list (calendar-gregorian-from-absolute
                    (calendar-dayname-on-or-before 6 (- abs-p 14)))
                   "Shabbat HaHodesh")
             (list (calendar-gregorian-from-absolute
                    (calendar-dayname-on-or-before 6 (1- abs-p)))
                   "Shabbat HaGadol")
             (list (calendar-gregorian-from-absolute (1- abs-p))
                   "Erev Passover")
             (list (calendar-gregorian-from-absolute (1+ abs-p))
                   "Passover (second day)")
             (list (calendar-gregorian-from-absolute (+ abs-p 2))
                   "Hol Hamoed Passover (first day)")
             (list (calendar-gregorian-from-absolute (+ abs-p 3))
                   "Hol Hamoed Passover (second day)")
             (list (calendar-gregorian-from-absolute (+ abs-p 4))
                   "Hol Hamoed Passover (third day)")
             (list (calendar-gregorian-from-absolute (+ abs-p 5))
                   "Hol Hamoed Passover (fourth day)")
             (list (calendar-gregorian-from-absolute (+ abs-p 6))
                   "Passover (seventh day)")
             (list (calendar-gregorian-from-absolute (+ abs-p 7))
                   "Passover (eighth day)")
             (list (calendar-gregorian-from-absolute (+ abs-p 12))
                   "Yom HaShoah")
             (list (calendar-gregorian-from-absolute
                    (if (zerop (% abs-p 7))
                        (+ abs-p 18)
                      (if (= (% abs-p 7) 6)
                          (+ abs-p 19)
                        (+ abs-p 20))))
                   "Yom HaAtzma'ut")
             (list (calendar-gregorian-from-absolute (+ abs-p 33))
                   "Lag BaOmer")
             (list (calendar-gregorian-from-absolute (+ abs-p 43))
                   "Yom Yerushalim")
             (list (calendar-gregorian-from-absolute (+ abs-p 49))
                   "Erev Shavuot")
             (list (calendar-gregorian-from-absolute (+ abs-p 51))
                   "Shavuot (second day)")))
           (output-list
             (filter-visible-calendar-holidays mandatory)))
      (if all-hebrew-calendar-holidays
          (setq output-list
                (append 
                 (filter-visible-calendar-holidays optional)
                 output-list)))
      output-list)))

(defun holiday-tisha-b-av-etc ()
  "List of dates around Tisha B'Av, as visible in calendar window."
  (if (or (< displayed-month 5)
          (> displayed-month 9))
      nil;; None of the dates is visible
    (let* ((abs-t-a (calendar-absolute-from-hebrew
                      (list 5 9 (+ displayed-year 3760)))))

      (filter-visible-calendar-holidays
       (list 
        (list (calendar-gregorian-from-absolute
               (if (= (% abs-t-a 7) 6) (- abs-t-a 20) (- abs-t-a 21)))
              "Tzom Tammuz")
        (list (calendar-gregorian-from-absolute
               (calendar-dayname-on-or-before 6 abs-t-a))
              "Shabbat Hazon")
        (list (calendar-gregorian-from-absolute
               (if (= (% abs-t-a 7) 6) (1+ abs-t-a) abs-t-a))
              "Tisha B'Av")
        (list (calendar-gregorian-from-absolute
               (calendar-dayname-on-or-before 6 (+ abs-t-a 7)))
              "Shabbat Nahamu"))))))

(defun list-hebrew-diary-entries ()
  "Add any Hebrew date entries from the diary file to `diary-entries-list'.
Hebrew date diary entries must be prefaced by `hebrew-diary-entry-symbol'
\(normally an `H').  The same diary date forms govern the style of the Hebrew
calendar entries, except that the Hebrew month names must be spelled in full.
The Hebrew months are numbered from 1 to 13 with Nisan being 1, 12 being
Adar I and 13 being Adar II; you must use `Adar I' if you want Adar of a
common Hebrew year.  If a Hebrew date diary entry begins with a
`diary-nonmarking-symbol', the entry will appear in the diary listing, but will
not be marked in the calendar.  This function is provided for use with the
`nongregorian-diary-listing-hook'."
  (if (< 0 number)
      (let ((buffer-read-only nil)
            (diary-modified (buffer-modified-p))
            (gdate original-date)
            (mark (regexp-quote diary-nonmarking-symbol)))
        (calendar-for-loop i from 1 to number do
           (let* ((d diary-date-forms)
                  (hdate (calendar-hebrew-from-absolute 
                          (calendar-absolute-from-gregorian gdate)))
                  (month (extract-calendar-month hdate))
                  (day (extract-calendar-day hdate))
                  (year (extract-calendar-year hdate)))
             (while d
               (let*
                   ((date-form (if (equal (car (car d)) 'backup)
                                   (cdr (car d))
                                 (car d)))
                    (backup (equal (car (car d)) 'backup))
                    (dayname
                     (concat
                      (calendar-day-name gdate) "\\|"
                      (substring (calendar-day-name gdate) 0 3) ".?"))
                    (calendar-month-name-array
                     calendar-hebrew-month-name-array-leap-year)
                    (monthname
                     (concat
                      "\\*\\|"
                      (calendar-month-name month)))
                    (month (concat "\\*\\|0*" (int-to-string month)))
                    (day (concat "\\*\\|0*" (int-to-string day)))
                    (year
                     (concat
                      "\\*\\|0*" (int-to-string year)
                      (if abbreviated-calendar-year
                          (concat "\\|" (int-to-string (% year 100)))
                        "")))
                    (regexp
                     (concat
                      "\\(\\`\\|\^M\\|\n\\)" mark "?"
                      (regexp-quote hebrew-diary-entry-symbol)
                      "\\("
                      (mapconcat 'eval date-form "\\)\\(")
                      "\\)"))
                    (case-fold-search t))
                 (goto-char (point-min))
                 (while (re-search-forward regexp nil t)
                   (if backup (re-search-backward "\\<" nil t))
                   (if (and (or (char-equal (preceding-char) ?\^M)
                                (char-equal (preceding-char) ?\n))
                            (not (looking-at " \\|\^I")))
                       ;;  Diary entry that consists only of date.
                       (backward-char 1)
                     ;;  Found a nonempty diary entry--make it visible and
                     ;;  add it to the list.
                     (let ((entry-start (point))
                           (date-start))
                       (re-search-backward "\^M\\|\n\\|\\`")
                       (setq date-start (point))
                       (re-search-forward "\^M\\|\n" nil t 2)
                       (while (looking-at " \\|\^I")
                         (re-search-forward "\^M\\|\n" nil t))
                       (backward-char 1)
                       (subst-char-in-region date-start (point) ?\^M ?\n t)
                       (add-to-diary-list
                         gdate (buffer-substring entry-start (point)))))))
               (setq d (cdr d))))
           (setq gdate
                 (calendar-gregorian-from-absolute
                  (1+ (calendar-absolute-from-gregorian gdate)))))
           (set-buffer-modified-p diary-modified))
        (goto-char (point-min))))

(defun mark-hebrew-diary-entries ()
  "Mark days in the calendar window that have Hebrew date diary entries.
Each entry in diary-file (or included files) visible in the calendar window
is marked.  Hebrew date entries are prefaced by a hebrew-diary-entry-symbol
\(normally an `H').  The same diary-date-forms govern the style of the Hebrew
calendar entries, except that the Hebrew month names must be spelled in full.
The Hebrew months are numbered from 1 to 13 with Nisan being 1, 12 being
Adar I and 13 being Adar II; you must use `Adar I' if you want Adar of a
common Hebrew year.  Hebrew date diary entries that begin with a
diary-nonmarking symbol will not be marked in the calendar.  This function
is provided for use as part of the nongregorian-diary-marking-hook."
  (let ((d diary-date-forms))
    (while d
      (let*
          ((date-form (if (equal (car (car d)) 'backup)
                          (cdr (car d))
                        (car d)));; ignore 'backup directive
           (dayname (diary-name-pattern calendar-day-name-array))
           (monthname
            (concat
             (diary-name-pattern calendar-hebrew-month-name-array-leap-year t)
             "\\|\\*"))
           (month "[0-9]+\\|\\*")
           (day "[0-9]+\\|\\*")
           (year "[0-9]+\\|\\*")
           (l (length date-form))
           (d-name-pos (- l (length (memq 'dayname date-form))))
           (d-name-pos (if (/= l d-name-pos) (+ 2 d-name-pos)))
           (m-name-pos (- l (length (memq 'monthname date-form))))
           (m-name-pos (if (/= l m-name-pos) (+ 2 m-name-pos)))
           (d-pos (- l (length (memq 'day date-form))))
           (d-pos (if (/= l d-pos) (+ 2 d-pos)))
           (m-pos (- l (length (memq 'month date-form))))
           (m-pos (if (/= l m-pos) (+ 2 m-pos)))
           (y-pos (- l (length (memq 'year date-form))))
           (y-pos (if (/= l y-pos) (+ 2 y-pos)))
           (regexp
            (concat
             "\\(\\`\\|\^M\\|\n\\)"
             (regexp-quote hebrew-diary-entry-symbol)
             "\\("
             (mapconcat 'eval date-form "\\)\\(")
             "\\)"))
           (case-fold-search t))
        (goto-char (point-min))
        (while (re-search-forward regexp nil t)
          (let* ((dd-name
                  (if d-name-pos
                      (buffer-substring
                       (match-beginning d-name-pos)
                       (match-end d-name-pos))))
                 (mm-name
                  (if m-name-pos
                      (buffer-substring
                       (match-beginning m-name-pos)
                       (match-end m-name-pos))))
                 (mm (string-to-int
                      (if m-pos
                          (buffer-substring
                           (match-beginning m-pos)
                           (match-end m-pos))
                        "")))
                 (dd (string-to-int
                      (if d-pos
                          (buffer-substring
                           (match-beginning d-pos)
                           (match-end d-pos))
                        "")))
                 (y-str (if y-pos
                            (buffer-substring
                             (match-beginning y-pos)
                             (match-end y-pos))))
                 (yy (if (not y-str)
                         0
                       (if (and (= (length y-str) 2)
                                abbreviated-calendar-year)
                           (let* ((current-y
                                   (extract-calendar-year
                                    (calendar-hebrew-from-absolute
                                     (calendar-absolute-from-gregorian
                                      (calendar-current-date)))))
                                  (y (+ (string-to-int y-str)
                                        (* 100 (/ current-y 100)))))
                             (if (> (- y current-y) 50)
                                 (- y 100)
                               (if (> (- current-y y) 50)
                                   (+ y 100)
                                 y)))
                         (string-to-int y-str)))))
            (if dd-name
                (mark-calendar-days-named
                 (cdr (assoc (capitalize (substring dd-name 0 3))
                             (calendar-make-alist
                               calendar-day-name-array
                               0
                              '(lambda (x) (substring x 0 3))))))
              (if mm-name
                  (if (string-equal mm-name "*")
                      (setq mm 0)
                    (setq
                      mm
                      (cdr 
                        (assoc
                          (capitalize mm-name)
                            (calendar-make-alist
                               calendar-hebrew-month-name-array-leap-year))))))
              (mark-hebrew-calendar-date-pattern mm dd yy)))))
      (setq d (cdr d)))))

(defun mark-hebrew-calendar-date-pattern (month day year)
  "Mark dates in calendar window that conform to Hebrew date MONTH/DAY/YEAR.
A value of 0 in any position is a wildcard."
  (save-excursion
    (set-buffer calendar-buffer)
    (if (and (/= 0 month) (/= 0 day))
        (if (/= 0 year)
            ;; Fully specified Hebrew date.
            (let ((date (calendar-gregorian-from-absolute
                         (calendar-absolute-from-hebrew
                          (list month day year)))))
              (if (calendar-date-is-visible-p date)
                  (mark-visible-calendar-date date)))
          ;; Month and day in any year--this taken from the holiday stuff.
          (if (memq displayed-month;;  This test is only to speed things up a
                    (list          ;;  bit; it works fine without the test too.
                     (if (< 11 month) (- month 11) (+ month 1))
                     (if (< 10 month) (- month 10) (+ month 2))
                     (if (<  9 month) (- month  9) (+ month 3))
                     (if (<  8 month) (- month  8) (+ month 4))
                     (if (<  7 month) (- month  7) (+ month 5))))
              (let ((m1 displayed-month)
                    (y1 displayed-year)
                    (m2 displayed-month)
                    (y2 displayed-year)
                    (year))
                (increment-calendar-month m1 y1 -1)
                (increment-calendar-month m2 y2 1)
                (let* ((start-date (calendar-absolute-from-gregorian
                                    (list m1 1 y1)))
                       (end-date (calendar-absolute-from-gregorian
                                  (list m2
                                        (calendar-last-day-of-month m2 y2)
                                        y2)))
                       (hebrew-start
                        (calendar-hebrew-from-absolute start-date))
                       (hebrew-end (calendar-hebrew-from-absolute end-date))
                       (hebrew-y1 (extract-calendar-year hebrew-start))
                       (hebrew-y2 (extract-calendar-year hebrew-end)))
                  (setq year (if (< 6 month) hebrew-y2 hebrew-y1))
                  (let ((date (calendar-gregorian-from-absolute
                               (calendar-absolute-from-hebrew
                                (list month day year)))))
                    (if (calendar-date-is-visible-p date)
                        (mark-visible-calendar-date date)))))))
      ;; Not one of the simple cases--check all visible dates for match.
      ;; Actually, the following code takes care of ALL of the cases, but
      ;; it's much too slow to be used for the simple (common) cases.
      (let ((m displayed-month)
            (y displayed-year)
            (first-date)
            (last-date))
        (increment-calendar-month m y -1)
        (setq first-date
              (calendar-absolute-from-gregorian
               (list m 1 y)))
        (increment-calendar-month m y 2)
        (setq last-date
              (calendar-absolute-from-gregorian
               (list m (calendar-last-day-of-month m y) y)))
        (calendar-for-loop date from first-date to last-date do
          (let* ((h-date (calendar-hebrew-from-absolute date))
                 (h-month (extract-calendar-month h-date))
                 (h-day (extract-calendar-day h-date))
                 (h-year (extract-calendar-year h-date)))
            (and (or (zerop month)
                     (= month h-month))
                 (or (zerop day)
                     (= day h-day))
                 (or (zerop year)
                     (= year h-year))
                 (mark-visible-calendar-date
                  (calendar-gregorian-from-absolute date)))))))))

(defun insert-hebrew-diary-entry (arg)
  "Insert a diary entry.
For the Hebrew date corresponding to the date indicated by point.
Prefix arg will make the entry nonmarking."
  (interactive "P")
  (let* ((calendar-month-name-array
          calendar-hebrew-month-name-array-leap-year))
    (make-diary-entry
     (concat
      hebrew-diary-entry-symbol
      (calendar-date-string 
       (calendar-hebrew-from-absolute
        (calendar-absolute-from-gregorian
         (calendar-cursor-to-date t)))
       nil t))
     arg)))

(defun insert-monthly-hebrew-diary-entry (arg)
  "Insert a monthly diary entry.
For the day of the Hebrew month 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 " * ") '("* " day )))
         (calendar-month-name-array
          calendar-hebrew-month-name-array-leap-year))
    (make-diary-entry
     (concat
      hebrew-diary-entry-symbol
      (calendar-date-string 
       (calendar-hebrew-from-absolute
        (calendar-absolute-from-gregorian
         (calendar-cursor-to-date t)))))
     arg)))

(defun insert-yearly-hebrew-diary-entry (arg)
  "Insert an annual diary entry.
For the day of the Hebrew 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-hebrew-month-name-array-leap-year))
    (make-diary-entry
     (concat
      hebrew-diary-entry-symbol
      (calendar-date-string 
       (calendar-hebrew-from-absolute
        (calendar-absolute-from-gregorian
         (calendar-cursor-to-date t)))))
     arg)))

;;;###autoload
(defun list-yahrzeit-dates (death-date start-year end-year)
  "List Yahrzeit dates for *Gregorian* DEATH-DATE from START-YEAR to END-YEAR.
When called interactively from the calendar window, the date of death is taken
from the cursor position."
  (interactive
   (let* ((death-date
           (if (equal (current-buffer) (get-buffer calendar-buffer))
               (calendar-cursor-to-date)
             (let* ((today (calendar-current-date))
                    (year (calendar-read
                           "Year of death (>0): "
                           '(lambda (x) (> x 0))
                           (int-to-string (extract-calendar-year today))))
                    (month-array calendar-month-name-array)
                    (completion-ignore-case t)
                    (month (cdr (assoc
                                 (capitalize
                                  (completing-read
                                   "Month of death (name): "
                                   (mapcar 'list (append month-array nil))
                                   nil t))
                                 (calendar-make-alist
                                  month-array 1 'capitalize))))
                    (last (calendar-last-day-of-month month year))
                    (day (calendar-read
                          (format "Day of death (1-%d): " last)
                          '(lambda (x) (and (< 0 x) (<= x last))))))
               (list month day year))))
          (death-year (extract-calendar-year death-date))
          (start-year (calendar-read
                       (format "Starting year of Yahrzeit table (>%d): "
                               death-year)
                       '(lambda (x) (> x death-year))
                       (int-to-string (1+ death-year))))
          (end-year (calendar-read
                     (format "Ending year of Yahrzeit table (>=%d): "
                             start-year)
                       '(lambda (x) (>= x start-year)))))
   (list death-date start-year end-year)))
  (message "Computing yahrzeits...")
  (let* ((yahrzeit-buffer "*Yahrzeits*")
         (h-date (calendar-hebrew-from-absolute
                  (calendar-absolute-from-gregorian death-date)))
         (h-month (extract-calendar-month h-date))
         (h-day (extract-calendar-day h-date))
         (h-year (extract-calendar-year h-date)))
    (set-buffer (get-buffer-create yahrzeit-buffer))
    (setq buffer-read-only nil)
    (calendar-set-mode-line
     (format "Yahrzeit dates for %s = %s"
             (calendar-date-string death-date)
             (let ((calendar-month-name-array
                    (if (hebrew-calendar-leap-year-p h-year)
                        calendar-hebrew-month-name-array-leap-year
                      calendar-hebrew-month-name-array-common-year)))
               (calendar-date-string h-date nil t))))
    (erase-buffer)
    (goto-char (point-min))
    (calendar-for-loop i from start-year to end-year do
        (insert
         (calendar-date-string
          (calendar-gregorian-from-absolute
           (hebrew-calendar-yahrzeit
            h-date
            (extract-calendar-year
             (calendar-hebrew-from-absolute
              (calendar-absolute-from-gregorian (list 1 1 i))))))) "\n"))
    (goto-char (point-min))
    (set-buffer-modified-p nil)
    (setq buffer-read-only t)
    (display-buffer yahrzeit-buffer)
    (message "Computing yahrzeits...done")))

(defun diary-hebrew-date ()
  "Hebrew calendar equivalent of date diary entry."
  (format "Hebrew date (until sunset): %s" (calendar-hebrew-date-string date)))

(defun diary-omer ()
  "Omer count diary entry.
Entry applies if date is within 50 days after Passover."
  (let* ((passover
          (calendar-absolute-from-hebrew
           (list 1 15 (+ (extract-calendar-year date) 3760))))
         (omer (- (calendar-absolute-from-gregorian date) passover))
         (week (/ omer 7))
         (day (% omer 7)))
    (if (and (> omer 0) (< omer 50))
        (format "Day %d%s of the omer (until sunset)"
                omer
                (if (zerop week)
                    ""
                  (format ", that is, %d week%s%s"
                          week
                          (if (= week 1) "" "s")
                          (if (zerop day)
                              ""
                            (format " and %d day%s"
                                    day (if (= day 1) "" "s")))))))))

(defun diary-yahrzeit (death-month death-day death-year)
  "Yahrzeit diary entry--entry applies if date is yahrzeit or the day before.
Parameters are DEATH-MONTH, DEATH-DAY, DEATH-YEAR; the diary entry is assumed
to be the name of the person.  Date of death is on the *civil* calendar;
although the date of death is specified by the civil calendar, the proper
Hebrew calendar yahrzeit is determined.  If `european-calendar-style' is t, the
order of the parameters is changed to DEATH-DAY, DEATH-MONTH, DEATH-YEAR."
  (let* ((h-date (calendar-hebrew-from-absolute
                  (calendar-absolute-from-gregorian
                   (if european-calendar-style
                       (list death-day death-month death-year)
                   (list death-month death-day death-year)))))
         (h-month (extract-calendar-month h-date))
         (h-day (extract-calendar-day h-date))
         (h-year (extract-calendar-year h-date))
         (d (calendar-absolute-from-gregorian date))
         (yr (extract-calendar-year (calendar-hebrew-from-absolute d)))
         (diff (- yr h-year))
         (y (hebrew-calendar-yahrzeit h-date yr)))
    (if (and (> diff 0) (or (= y d) (= y (1+ d))))
        (format "Yahrzeit of %s%s: %d%s anniversary"
                entry
                (if (= y d) "" " (evening)")
                diff
                (cond ((= (% diff 10) 1) "st")
                      ((= (% diff 10) 2) "nd")
                      ((= (% diff 10) 3) "rd")
                      (t "th"))))))

(defun diary-rosh-hodesh ()
  "Rosh Hodesh diary entry.
Entry applies if date is Rosh Hodesh, the day before, or the Saturday before."
  (let* ((d (calendar-absolute-from-gregorian date))
         (h-date (calendar-hebrew-from-absolute d))
         (h-month (extract-calendar-month h-date))
         (h-day (extract-calendar-day h-date))
         (h-year (extract-calendar-year h-date))
         (leap-year (hebrew-calendar-leap-year-p h-year))
         (last-day (hebrew-calendar-last-day-of-month h-month h-year))
         (h-month-names
          (if leap-year
              calendar-hebrew-month-name-array-leap-year
            calendar-hebrew-month-name-array-common-year))
         (this-month (aref h-month-names (1- h-month)))
         (h-yesterday (extract-calendar-day
                       (calendar-hebrew-from-absolute (1- d)))))
    (if (or (= h-day 30) (and (= h-day 1) (/= h-month 7)))
        (format
         "Rosh Hodesh %s"
         (if (= h-day 30)
             (format
              "%s (first day)"
              ;; next month must be in the same year since this
              ;; month can't be the last month of the year since
              ;; it has 30 days
              (aref h-month-names h-month))
           (if (= h-yesterday 30)
               (format "%s (second day)" this-month)
             this-month)))
      (if (= (% d 7) 6);; Saturday--check for Shabbat Mevarhim
          (cond ((and (> h-day 22) (/= h-month 6) (= 29 last-day))
                 (format "Mevarhim Rosh Hodesh %s (%s)"
                         (aref h-month-names
                               (if (= h-month
                                      (hebrew-calendar-last-month-of-year
                                       h-year))
                                   0 h-month))
                         (aref calendar-day-name-array (- 29 h-day))))
                ((and (< h-day 30) (> h-day 22) (= 30 last-day))
                 (format "Mevarhim Rosh Hodesh %s (%s-%s)"
                         (aref h-month-names h-month)
                         (if (= h-day 29)
                             "tomorrow"
                           (aref calendar-day-name-array (- 29 h-day)))
                         (aref calendar-day-name-array
                               (% (- 30 h-day) 7)))))
        (if (and (= h-day 29) (/= h-month 6))
            (format "Erev Rosh Hodesh %s"
                    (aref h-month-names
                          (if (= h-month
                                 (hebrew-calendar-last-month-of-year
                                  h-year))
                              0 h-month))))))))

(defun diary-parasha ()
  "Parasha diary entry--entry applies if date is a Saturday."
  (let ((d (calendar-absolute-from-gregorian date)))
    (if (= (% d 7) 6);;  Saturday
        (let*
            ((h-year (extract-calendar-year
                      (calendar-hebrew-from-absolute d)))
             (rosh-hashanah
              (calendar-absolute-from-hebrew (list 7 1 h-year)))
             (passover
              (calendar-absolute-from-hebrew (list 1 15 h-year)))
             (rosh-hashanah-day
              (aref calendar-day-name-array (% rosh-hashanah 7)))
             (passover-day
              (aref calendar-day-name-array (% passover 7)))
             (long-h (hebrew-calendar-long-heshvan-p h-year))
             (short-k (hebrew-calendar-short-kislev-p h-year))
             (type (cond ((and long-h (not short-k)) "complete")
                         ((and (not long-h) short-k) "incomplete")
                         (t "regular")))
             (year-format
              (symbol-value
               (intern (format "hebrew-calendar-year-%s-%s-%s";; keviah
                               rosh-hashanah-day type passover-day))))
             (first-saturday;; of Hebrew year
              (calendar-dayname-on-or-before 6 (+ 6 rosh-hashanah)))
             (saturday;; which Saturday of the Hebrew year
              (/ (- d first-saturday) 7))
             (parasha (aref year-format saturday)))
          (if parasha
              (format
               "Parashat %s"
               (if (listp parasha);; Israel differs from diaspora
                   (if (car parasha)
                       (format "%s (diaspora), %s (Israel)"
                               (hebrew-calendar-parasha-name (car parasha))
                               (hebrew-calendar-parasha-name (cdr parasha)))
                     (format "%s (Israel)"
                             (hebrew-calendar-parasha-name (cdr parasha))))
                 (hebrew-calendar-parasha-name parasha))))))))

(defvar hebrew-calendar-parashiot-names
["Bereshith"   "Noah"      "Lech L'cha" "Vayera"    "Hayei Sarah" "Toledoth"
 "Vayetze"     "Vayishlah" "Vayeshev"   "Mikketz"   "Vayiggash"   "Vayhi"
 "Shemoth"     "Vaera"     "Bo"         "Beshallah" "Yithro"      "Mishpatim"
 "Terumah"     "Tetzavveh" "Ki Tissa"   "Vayakhel"  "Pekudei"     "Vayikra"
 "Tzav"        "Shemini"   "Tazria"     "Metzora"   "Aharei Moth" "Kedoshim"
 "Emor"        "Behar"     "Behukkotai" "Bemidbar"  "Naso"       "Behaalot'cha"
 "Shelah L'cha" "Korah"    "Hukkath"    "Balak"     "Pinhas"      "Mattoth"
 "Masei"       "Devarim"   "Vaethanan"  "Ekev"      "Reeh"        "Shofetim"
 "Ki Tetze"    "Ki Tavo"   "Nitzavim"   "Vayelech"  "Haazinu"]
  "The names of the parashiot in the Torah.")

;; The seven ordinary year types (keviot)

(defconst hebrew-calendar-year-Saturday-incomplete-Sunday
  [nil 52 nil nil 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 [21 22]
    23 24 nil 25 [26 27] [28 29] 30 [31 32] 33 34 35 36 37 38 39 40 [41 42]
    43 44 45 46 47 48 49 50]
  "The structure of the parashiot.
Hebrew year starts on Saturday, is `incomplete' (Heshvan and Kislev each have
29 days), and has Passover start on Sunday.")

(defconst hebrew-calendar-year-Saturday-complete-Tuesday
  [nil 52 nil nil 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 [21 22]
    23 24 nil 25 [26 27] [28 29] 30 [31 32] 33 34 35 36 37 38 39 40 [41 42]
    43 44 45 46 47 48 49 [50 51]]
  "The structure of the parashiot.
Hebrew year that starts on Saturday, is `complete' (Heshvan and Kislev each
have 30 days), and has Passover start on Tuesday.")

(defconst hebrew-calendar-year-Monday-incomplete-Tuesday
  [51 52 nil 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 [21 22]
    23 24 nil 25 [26 27] [28 29] 30 [31 32] 33 34 35 36 37 38 39 40 [41 42]
    43 44 45 46 47 48 49 [50 51]]
  "The structure of the parashiot.
Hebrew year that starts on Monday, is `incomplete' (Heshvan and Kislev each
have 29 days), and has Passover start on Tuesday.")

(defconst hebrew-calendar-year-Monday-complete-Thursday
  [51 52 nil 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 [21 22]
   23 24 nil 25 [26 27] [28 29] 30 [31 32] 33 (nil . 34) (34 . 35) (35 . 36)
   (36 . 37) (37 . 38) ([38 39] . 39) 40 [41 42] 43 44 45 46 47 48 49 [50 51]]
  "The structure of the parashiot.
Hebrew year that starts on Monday, is `complete' (Heshvan and Kislev each have
30 days), and has Passover start on Thursday.")

(defconst hebrew-calendar-year-Tuesday-regular-Thursday
  [51 52 nil 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 [21 22]
   23 24 nil 25 [26 27] [28 29] 30 [31 32] 33 (nil . 34) (34 . 35) (35 . 36)
   (36 . 37) (37 . 38) ([38 39] . 39) 40 [41 42] 43 44 45 46 47 48 49 [50 51]]
  "The structure of the parashiot.
Hebrew year that starts on Tuesday, is `regular' (Heshvan has 29 days and
Kislev has 30 days), and has Passover start on Thursday.")

(defconst hebrew-calendar-year-Thursday-regular-Saturday
  [52 nil nil 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 [21 22] 23
   24 nil (nil . 25) (25 . [26 27]) ([26 27] . [28 29]) ([28 29] . 30)
   (30 . 31) ([31 32] . 32) 33 34 35 36 37 38 39 40 [41 42] 43 44 45 46 47 48
   49 50]
  "The structure of the parashiot.
Hebrew year that starts on Thursday, is `regular' (Heshvan has 29 days and
Kislev has 30 days), and has Passover start on Saturday.")

(defconst hebrew-calendar-year-Thursday-complete-Sunday
  [52 nil nil 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
    23 24 nil 25 [26 27] [28 29] 30 [31 32] 33 34 35 36 37 38 39 40 [41 42]
    43 44 45 46 47 48 49 50]
  "The structure of the parashiot.
Hebrew year that starts on Thursday, is `complete' (Heshvan and Kislev each
have 30 days), and has Passover start on Sunday.")

;; The seven leap year types (keviot)

(defconst hebrew-calendar-year-Saturday-incomplete-Tuesday
  [nil 52 nil nil 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
    23 24 25 26 27 nil 28 29 30 31 32 33 34 35 36 37 38 39 40 [41 42]
    43 44 45 46 47 48 49 [50 51]]
  "The structure of the parashiot.
Hebrew year that starts on Saturday, is `incomplete' (Heshvan and Kislev each
have 29 days), and has Passover start on Tuesday.")

(defconst hebrew-calendar-year-Saturday-complete-Thursday
  [nil 52 nil nil 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
   23 24 25 26 27 nil 28 29 30 31 32 33 (nil . 34) (34 . 35) (35 . 36)
   (36 . 37) (37 . 38) ([38 39] . 39) 40 [41 42] 43 44 45 46 47 48 49 [50 51]]
  "The structure of the parashiot.
Hebrew year that starts on Saturday, is `complete' (Heshvan and Kislev each
have 30 days), and has Passover start on Thursday.")

(defconst hebrew-calendar-year-Monday-incomplete-Thursday
  [51 52 nil 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
   23 24 25 26 27 nil 28 29 30 31 32 33 (nil . 34) (34 . 35) (35 . 36)
   (36 . 37) (37 . 38) ([38 39] . 39) 40 [41 42] 43 44 45 46 47 48 49 [50 51]]
  "The structure of the parashiot.
Hebrew year that starts on Monday, is `incomplete' (Heshvan and Kislev each
have 29 days), and has Passover start on Thursday.")

(defconst hebrew-calendar-year-Monday-complete-Saturday
  [51 52 nil 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
   23 24 25 26 27 nil (nil . 28) (28 . 29) (29 . 30) (30 . 31) (31 . 32)
   (32 . 33) (33 . 34) (34 . 35) (35 . 36) (36 . 37) (37 . 38) (38 . 39)
   (39 . 40) (40 . 41) ([41 42] . 42) 43 44 45 46 47 48 49 50]
  "The structure of the parashiot.
Hebrew year that starts on Monday, is `complete' (Heshvan and Kislev each have
30 days), and has Passover start on Saturday.")

(defconst hebrew-calendar-year-Tuesday-regular-Saturday
  [51 52 nil 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
   23 24 25 26 27 nil (nil . 28) (28 . 29) (29 . 30) (30 . 31) (31 . 32)
   (32 . 33) (33 . 34) (34 . 35) (35 . 36) (36 . 37) (37 . 38) (38 . 39)
   (39 . 40) (40 . 41) ([41 42] . 42) 43 44 45 46 47 48 49 50]
  "The structure of the parashiot.
Hebrew year that starts on Tuesday, is `regular' (Heshvan has 29 days and
Kislev has 30 days), and has Passover start on Saturday.")

(defconst hebrew-calendar-year-Thursday-incomplete-Sunday
  [52 nil nil 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
    23 24 25 26 27 28 nil 29 30 31 32 33 34 35 36 37 38 39 40 41 42
    43 44 45 46 47 48 49 50]
  "The structure of the parashiot.
Hebrew year that starts on Thursday, is `incomplete' (Heshvan and Kislev both
have 29 days), and has Passover start on Sunday.")

(defconst hebrew-calendar-year-Thursday-complete-Tuesday
  [52 nil nil 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
    23 24 25 26 27 28 nil 29 30 31 32 33 34 35 36 37 38 39 40 41 42
    43 44 45 46 47 48 49 [50 51]]
  "The structure of the parashiot.
Hebrew year that starts on Thursday, is `complete' (Heshvan and Kislev both
have 30 days), and has Passover start on Tuesday.")

(defun hebrew-calendar-parasha-name (p)
  "Name(s) corresponding to parasha P."
  (if (arrayp p);; combined parasha
      (format "%s/%s"
              (aref hebrew-calendar-parashiot-names (aref p 0))
              (aref hebrew-calendar-parashiot-names (aref p 1)))
    (aref hebrew-calendar-parashiot-names p)))

(provide 'cal-hebrew)

;;; cal-hebrew.el ends here
