Function numerus::numerus_lib::int_to_roman::int_to_roman_lower

pub fn int_to_roman_lower(number: i32) -> Option<String>

Convert the given numer into a lowercase roman numeral. This function fails if the given numer is not representable in the roman numerical system (i.e. number <= 0).

An error example

    use numerus::int_to_roman_lower;
     
    /*
        It is not possible to represent 
        a negative numer in the roman 
        numerical system
    */
    let wrong_number = -45;
    match int_to_roman_lower(wrong_number) {
        Some(_) => assert!(false),
        None => assert!(true)
    };

A correct convertion

    use numerus::int_to_roman_lower;
 
    let convertible_number = 39;
    match int_to_roman_lower(convertible_number) {
        Some(roman) => assert_eq!(roman, "xxxix"),
        None => assert!(false)
    };