//prefix    前缀 操作符在变量前//postfix   后缀//infix     中间//不要和系统冲突即可prefix operator -!postfix operator ~~infix operator !!!class Person {    var name: String    var age: Int    init(name: String, age: Int) {        self.name = name        self.age = age    }    static prefix func -!(lhs: Person) -> Bool {        return lhs.age > 0    }    static postfix func ~~(lhs: Person) -> Bool {        return lhs.age < 0    }    static func !!!(lhs: Person, rhs: Person) -> Bool {        return lhs.age == rhs.age + 1    }}let p1 = Person(name: "", age: 2)let p2 = Person(name: "", age: 1)//使用：-!p1 p1~~p1 !!! p2