V. Calendar functions
The calendar functions are only available if you have compiled the
calendar extension in dl/calendar. Read dl/README for instructions
on using it.
The calendar extension presents a series of functions to simplify
converting between different calendar formats. The intermediary
or standard it is based on is the Julian Day Count. The Julian
Day Count is a count of days starting way earlier than any date
most people would need to track (somewhere around 4000bc). To
convert between calendar systems, you must first convert to Julian
Day Count, then to the calendar system of your choice. Julian Day
Count is very different from the Julian Calendar! For more
information on calendar systems visit http://genealogy.org/~scottlee/cal-overview.html. Excerpts from this
page are included in these instructions, and are in quotes.
- Table of Contents
- JDToGregorian — Converts Julian Day Count to Gregorian date
- GregorianToJD —
Converts a Gregorian date to Julian Day Count
- JDToJulian —
Converts a Julian Day Count to a Julian Calendar Date
- JulianToJD —
Converts a Julian Calendar date to Julian Day Count
- JDToJewish —
Converts a Julian Day Count to the Jewish Calendar
- JewishToJD —
Converts a date in the Jewish Calendar to Julian Day Count
- JDToFrench —
Converts a Julian Day Count to the French Republican Calendar
- FrenchToJD —
Converts a date from the French Republican Calendar to a Julian
Day Count
- JDMonthName — Returns a month name
- JDDayOfWeek — Returns the day of the week
- easter_date —
Get UNIX timestamp for midnight on Easter of a given year
- easter_days —
Get number of days after March 21 on which Easter falls for a
given year
- unixtojd — Convert UNIX timestamp to Julian Day
- jdtounix — Convert Julian Day to UNIX timestamp
