相关疑难解决方法(0)

在读取初始值设定项时,NSLocalizedString我看到某些参数默认为某个值default.什么是default关键词代表什么？

func NSLocalizedString(key: String, tableName: String? = default, bundle: NSBundle = default, value: String = default, #comment: String) -> String

在一个类中,我定义了一个私有常量,我尝试使用常量作为函数参数的默认值:

class Foo {
  // instance variable
  private let DefaultValue = 10

  // Compiler error: Cannot use instance member 'DefaultValue' as a default parameter
  public func doTask(amount: Int = DefaultValue) {
    ...
  }
}

但我收到编译器错误:Cannot use instance member 'DefaultValue' as a default parameter.

然后,我也尝试声明DefaultValue为private static:

class Foo {
      // static variable
      private static let DefaultValue = 10

      // Compiler error: Static let 'DefaultValue' is private and cannot be referenced from a default argument value …