omochimetaru

struct Stone { var name: String = "" { didSet { let newValue = name if recCount == 5 { return } recCount += 1 print("name.didSet begin: \(oldValue) -> \(newValue)") update() print("name.didSet end: \(oldValue) -> \(newValue)") } } var recCount = 0 mutating func update() { name = "jiro" } } var b = Stone() b.name = "taro"

Version:

swift-4.1.1-RELEASE

Output:

name.didSet begin: -> taro name.didSet begin: taro -> jiro name.didSet begin: jiro -> jiro name.didSet begin: jiro -> jiro name.didSet begin: jiro -> jiro name.didSet end: jiro -> jiro name.didSet end: jiro -> jiro name.didSet end: jiro -> jiro name.didSet end: taro -> jiro name.didSet end: -> taro

Error: