A Formatter subclass that formats numbers as Roman numerals. Supports numbers
from between 0 and 4 million (non-inclusive).
To use this formatter, create an instance of RomanNumeralFormatter and use it
like so:
let formatter = RomanNumeralFormatter()
let string = formatter.string(for: 42) // "XLII"let formatter = RomanNumeralFormatter()
var int = NSNumber(integerLiteral: 0) as AnyObject?
let success = formatter.getObjectValue(&int, for: "IX", errorDescription: nil)
if success {
let intValue = (int as? NSNumber)?.intValue // 9
}Most Roman numeral formatters stop at 4,000. However, using the Unicode overline character, we can represent larger numbers, up to (but not including) 4 million.
let formatter = RomanNumeralFormatter()
let string = formatter.string(for: 3_999_999) // "M̅M̅M̅C̅M̅X̅C̅I̅X̅CMXCIX"