这按预期工作
struct ProgrammingLanguage {
let name: String?
}
let language = ProgrammingLanguage(name: "Swift")
let mirror = Mirror(reflecting: language.name)
print(mirror.children.first?.value)
// Optional("Swift")
删除可选项时,它会打印出 nil
struct ProgrammingLanguage {
let name: String
}
let language = ProgrammingLanguage(name: "Swift")
let mirror = Mirror(reflecting: language.name)
print(mirror.children.first?.value)
// nil
有人可以解释为什么可选值存在一个值,否则它是 nil 吗?