Module calendrica-coptic-ethiopic
Coptic and Ethiopic calendar conversions.
Ported from "Calendrical Calculations" (4th edition) by Nachum Dershowitz and Edward M. Reingold. Original Lisp code (CALENDRICA 4.0) is Apache 2.0 licensed.
Info:
- Release: 0.1 2026-07-19
Functions
| coptic_leap_year (c_year) | True if `c_year` is a Coptic leap year. |
| fixed_from_coptic (c_date) | Fixed date of Coptic date `c_date`. |
| coptic_from_fixed (date) | Coptic date {year, month, day} equivalent to fixed `date`. |
| fixed_from_ethiopic (e_date) | Fixed date of Ethiopic date `e_date`. |
| ethiopic_from_fixed (date) | Ethiopic date {year, month, day} equivalent to fixed `date`. |
| coptic_in_gregorian (c_month, c_day, g_year) | Fixed dates of Coptic month `c_month`, day `c_day` that fall in Gregorian year `g_year`. |
| coptic_christmas (g_year) | Fixed dates of Coptic Christmas (Coptic month 4, day 29) in Gregorian year `g_year`. |
Functions
- coptic_leap_year (c_year)
-
True if `c_year` is a Coptic leap year.
Parameters:
- c_year number Coptic year.
Returns:
-
boolean
- fixed_from_coptic (c_date)
-
Fixed date of Coptic date `c_date`.
Parameters:
- c_date table Coptic date {year, month, day}.
Returns:
-
number
Fixed date.
- coptic_from_fixed (date)
-
Coptic date {year, month, day} equivalent to fixed `date`.
Parameters:
- date number Fixed date.
Returns:
-
table
{year, month, day}
- fixed_from_ethiopic (e_date)
-
Fixed date of Ethiopic date `e_date`.
Same structure as the Coptic calendar with a different epoch.
Parameters:
- e_date table Ethiopic date {year, month, day}.
Returns:
-
number
Fixed date.
- ethiopic_from_fixed (date)
-
Ethiopic date {year, month, day} equivalent to fixed `date`.
Parameters:
- date number Fixed date.
Returns:
-
table
{year, month, day}
- coptic_in_gregorian (c_month, c_day, g_year)
-
Fixed dates of Coptic month `c_month`, day `c_day` that fall in Gregorian year `g_year`.
Parameters:
- c_month number Coptic month.
- c_day number Coptic day.
- g_year number Gregorian year.
Returns:
-
table
List of fixed dates (0 or 1 entries).
- coptic_christmas (g_year)
-
Fixed dates of Coptic Christmas (Coptic month 4, day 29) in Gregorian year `g_year`.
Parameters:
- g_year number Gregorian year.
Returns:
-
{number,...}
Fixed dates of Coptic Christmas in the year.