gregorian

An implementation of the proleptic Gregorian calendar.
In this implementation, before the year 1 come year 0.
The library does not deal with times.
The Date type represents a date (year, month and day),
the Year type represents a calendar year,
the Month type represents a calendar month,
and the YearMonth type represents a month of a specific year.
Example
use gregorian::{Date, Month::*, Year, YearMonth};
assert!(Year::new(2020).has_leap_day(), true);
assert!(YearMonth::new(1900, February).total_days() == 28);
assert!(YearMonth::new(2000, February).total_days() == 29);
assert!(Year::new(2020).with_month(March).first_day() == Date::new(2020, March, 1).unwrap());
assert!(Year::new(2020).with_month(March).last_day() == Date::new(2020, March, 31).unwrap());
assert!(Year::new(2020).first_day() == Date::new(2020, 1, 1).unwrap());
assert!(Year::new(2020).last_day() == Date::new(2020, 12, 31).unwrap());
assert!(Date::new(2020, 2, 1).unwrap().day_of_year() == 32);