compound cases

Swift ⟩ enum ⟩

📗 參考

• Sarun ⟩ 3 lesser-known ways of using Swift enums (💈範例) - various pattern matching. ⭐️

💈範例

enum Job {
  case developer(exp: Int)
  case designer(exp: Int)
  case pm(exp: Int)
}

let job = Job.developer(exp: 5)
     
switch job {SS
  // ⭐️ compound cases with enums with associated values
  // 1. all cases have to include same set of value bindings (let exp)
  // 2. each binding has to be of the same type (Int)
  case .developer(let exp), .designer(let exp), .pm(let exp):
      print("You have \(exp) year(s) of experience")
}

// another example
enum Foo {
    case a(Int)
    case b(Int, Int)
    case c(Int, String, Int)
    case d(String)
}

let test = Foo.c(1, "c", 3)

switch test {
    // ⭐ same binding (let i), same type (Int)
    case .a(let i), .b(_, let i), .c(let i, _, _): print(i)     // 1
    default: break
}

switch test {
    // ⭐ order doesn't matter.
    case let .b(i, j), let .c(j, _, i): print("(\(i), \(j))")   // (3, 1)
    default: break
}