jw_calendar

https://github.com/karencohenjw/jw_calendar

== About JW Calendar A dependency-free civil-calendar engine for Ruby with proleptic Gregorian and Julian arithmetic, Julian Day Number conversions, ISO week and ordinal dates, month grids, reform cutovers, and boundary analysis. Civil dates are kept separate from instants and time zones. For printable calendar resources, see {2027 Calendar}[https://jwcalendar.com/yearly-calendar/] and {Blank Calendar}[https://jwcalendar.com/blank-calendar/].