(auto-mode-alist): Add snmp-mode patterns.

[gnu-emacs] / lisp / calendar / cal-mayan.el

diff --git a/lisp/calendar/cal-mayan.el b/lisp/calendar/cal-mayan.el
index 9fbf0b08d659f92f1eab335b4987273581d660fb..6ebc5b2e944a08f0b603ec9e52fff0b8d172ab4e 100644 (file)
--- a/lisp/calendar/cal-mayan.el
+++ b/lisp/calendar/cal-mayan.el
@@ -1,6 +1,6 @@
 ;;; cal-mayan.el --- calendar functions for the Mayan calendars.
 
-;; Copyright (C) 1992, 1993 Free Software Foundation, Inc.
+;; Copyright (C) 1992, 1993, 1995, 1997 Free Software Foundation, Inc.
 
 ;; Author: Stewart M. Clamen <clamen@cs.cmu.edu>
 ;;     Edward M. Reingold <reingold@cs.uiuc.edu>
@@ -20,8 +20,9 @@
 ;; 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, 675 Mass Ave, Cambridge, MA 02139, USA.
+;; 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:
 
@@ -43,6 +44,8 @@
 ;; Comments, improvements, and bug reports should be sent to Reingold.
 
 ;; Technical details of the Mayan calendrical calculations can be found in
+;; ``Calendrical Calculations'' by Nachum Dershowitz and Edward M. Reingold,
+;; Cambridge University Press (1997), and in
 ;; ``Calendrical Calculations, Part II: Three Historical Calendars''
 ;; by E. M. Reingold,  N. Dershowitz, and S. M. Clamen,
 ;; Software--Practice and Experience, Volume 23, Number 4 (April, 1993),
@@ -52,16 +55,11 @@
 
 (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
+(defconst calendar-mayan-days-before-absolute-zero 1137142
   "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 Spinden's correlation; using
-1142840 will give you Hochleitner's correlation.")
+This is the Goodman-Martinez-Thompson correlation used by almost all experts,
+but some use 1137140.  Using 1232041 gives you Spinden's correlation; using
+1142840 gives you Hochleitner's correlation.")
 
 (defconst calendar-mayan-haab-at-epoch '(8 . 18)
   "Mayan haab date at the epoch.")
@@ -175,10 +173,10 @@ Echo Mayan date if NOECHO is t."
 (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)))
@@ -286,7 +284,7 @@ Returns nil if such a tzolkin-haab combination is impossible."
 
 (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)))
@@ -303,7 +301,7 @@ Echo Mayan date if NOECHO is t."
 
 (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)))