| From https://docs.perl6.org/type/Date: "A Date is an immutable object identifying a day in the Gregorian calendar." (It's proleptic.) The days used in DateTime, which is compatible with the Date class, also identify days in the Gregorian calendar. (DateTime adopts RFC 3339[1].) The `is-leap-year` methods for both classes refer to the Gregorian calendar year. For a civil calendar independent date, use the `daycount` method to return a Modified Julian Day[2]. The `Dateish` role[3] abstracts from any particular civil calendar. I'm not aware of any routines, built in or in existing Perl 6 modules, for conversion to other calendars. [1] https://www.ietf.org/rfc/rfc3339.txt [2] http://tycho.usno.navy.mil/mjd.html [3] https://docs.perl6.org/type/Dateish |