struct Person: Hashable {
var age: Int
var name: String
var hashValue: Int { return age.hashValue ^ name.hashValue }
}

func ==(l: Person, r: Person) -> Bool { return l.age == r.age && l.name == r.name }

// ↓全部同じ
Person(age: 20, name: "a").hashValue
Person(age: 27, name: "b").hashValue
Person(age: 30, name: "c").hashValue