CodableRange.swift

struct Dice: Codable {
    var range: Range<Int>
    
    init<R: RangeExpression>(range expr: R) where R.Bound == Int {
        range  = expr.relative(to: Range<Int>(Int.min...Int.max-1))
    }
    
    
    func roll() -> Int {
        return Int.random(in: range)
    }   
}