kalendarium

A Rust library for converting dates to the Kalendarium Romanum, the calendar used by the ancient Romans. Unlike a modern calendar, days are displayed as the number of days until either the Kalends, the Nones, or the Ides. For a 31 day month, occur on the 1st, 7th, and 15th of the month.

For example, May 26th, 2025 would appear like this:

ante diem VII Kal. Iun. MMDCCLXXVIII a.u.c. diēs Lūnae

Meaning: there are 7 days until the Kalends of June (counting inclusively), it's 2778 years since the founding of Rome, and it's a Monday.

There is also a second library for converting Arabic numerals (1,2,3...) Roman numerals numerals (I, II, III ...) that handles very large numbers. Integers between 0 and 999,999 (inclusive) are supported. Any number beyond this range will return an OutOfRangeError.

Both uppercase and lowercase Roman numerals are supported.

Example usages

Display the date

Contruct a calendar date with the year, month, and day.

use kalendarium::Kalendarium;

let kal: Kalendarium = Kalendarium::new("2025", "5", "24").unwrap();
assert_eq!(kal.to_str, "ante diem IX Kal. Iun. MMDCCLXXVIII a.u.c. diēs Sāturnī");

Create Roman numerals

use kalendarium::RomanNumeral;

let num = RomanNumeral::new(616)?;
assert_eq!(num.to_string(), "DCXVI");

let num: RomanNumeral = 999_999.try_into().unwrap();
println!("{}", num);  // C̅M̅X̅C̅I̅X̅CMXCIX

License

GPL-3.0