;;; cal-mayan.el --- calendar functions for the Mayan calendars.
-;; Copyright (C) 1992, 1993 Free Software Foundation, Inc.
+;; Copyright (C) 1992, 1993, 1995 Free Software Foundation, Inc.
;; Author: Stewart M. Clamen <clamen@cs.cmu.edu>
;; Edward M. Reingold <reingold@cs.uiuc.edu>
;; 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. No author or distributor
-;; accepts responsibility to anyone for the consequences of using it
-;; or for whether it serves any particular purpose or works at all,
-;; unless he says so in writing. Refer to the GNU Emacs General Public
-;; License for full details.
-
-;; Everyone is granted permission to copy, modify and redistribute
-;; GNU Emacs, but only under the conditions described in the
-;; GNU Emacs General Public License. A copy of this license is
-;; supposed to have been given to you along with GNU Emacs so you
-;; can know your rights and responsibilities. It should be in a
-;; file named COPYING. Among other things, the copyright notice
-;; and this notice must be preserved on all copies.
+;; 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:
(require 'calendar)
-(defun mayan-adjusted-mod (m n)
- "Non-negative remainder of M/N with N instead of 0."
- (1+ (mod (1- m) n)))
-
(defconst calendar-mayan-days-before-absolute-zero 1137140
"Number of days of the Mayan calendar epoch before absolute day 0.
According to the Goodman-Martinez-Thompson correlation. This correlation is
not universally accepted, as it still a subject of astro-archeological
-research. Using 1232041 will give you the correlation used by Spinden.")
+research. Using 1232041 will give you Spinden's correlation; using
+1142840 will give you Hochleitner's correlation.")
(defconst calendar-mayan-haab-at-epoch '(8 . 18)
"Mayan haab date at the epoch.")
(defun calendar-mayan-tzolkin-from-absolute (date)
"Convert absolute DATE into a Mayan tzolkin date (a pair)."
(let* ((long-count (+ date calendar-mayan-days-before-absolute-zero))
- (day (mayan-adjusted-mod
+ (day (calendar-mod
(+ long-count (car calendar-mayan-tzolkin-at-epoch))
13))
- (name (mayan-adjusted-mod
+ (name (calendar-mod
(+ long-count (cdr calendar-mayan-tzolkin-at-epoch))
20)))
(cons day name)))
(defun calendar-next-calendar-round-date
(tzolkin-date haab-date &optional noecho)
- "Move cursor to next instance of Mayan HAAB-DATE TZOKLIN-DATE combination.
+ "Move cursor to next instance of Mayan HAAB-DATE TZOLKIN-DATE combination.
Echo Mayan date if NOECHO is t."
(interactive (list (calendar-read-mayan-tzolkin-date)
(calendar-read-mayan-haab-date)))
(defun calendar-previous-calendar-round-date
(tzolkin-date haab-date &optional noecho)
- "Move to previous instance of Mayan TZOKLIN-DATE HAAB-DATE combination.
+ "Move to previous instance of Mayan TZOLKIN-DATE HAAB-DATE combination.
Echo Mayan date if NOECHO is t."
(interactive (list (calendar-read-mayan-tzolkin-date)
(calendar-read-mayan-haab-date)))