继承，协议和静态字段

Question

如何在id和commonStaticField字段中删除重复内容？

struct S1 {
  let id: String       //note - it's let
  static let commonStaticField = "s1" //note - it's static
  let someField1: String
  let someField2: String
}

struct S2 {
  let id: String
  static let commonStaticField = "s2"
  let someField3: String
  let someField4: String
}

我尝试使用不同的变体：

protocol P1 {
  let id: String
  static let commonStaticField: String //static not allowed
}

但它并没有成功。我希望能够做到这一点：

struct S1: P1 {
  static let commonStaticField = "s1" //note - it's static and defined
  let someField1: String
  let someField2: String
}

let s1 = S1(id: "some id", someField1: "some field3", someField2: "some field2")