Access name of object being wrapped, in Swift property wrapper implementation

Question

I'm using Swift property wrappers to define something like:

@MyWrapper var foo: Int

And in the implementation of the property wrapper, I'd like to access the name of the variable, foo, as a string. Something like this:

@propertyWrapper
public struct MyWrapper<Type> {
  init() {
    // Get access to "foo" -- name of var as String
  }
}

Suggestions?

Answer 1

将变量名称传递给包装器；你可以使用这种替代方式。

@propertyWrapper
public struct MyWrapper<Type> {

  var wrappedValue: ... {
  set{.....}
  get{.....}
  }

  init(wrappedValue initialValue: Double, _ nameOfTheVariable: String ) {
      precondition(!nameOfTheVariable.isEmpty)
      //you can access nameOfTheVariable here
  }  
}

然后像下面一样使用它，

   @MyWrapper("foo") var foo: Int

注意：在 init 方法中必须提到wrappedValue。除非，它对我不起作用。

( init( wrappedValue初始值: Double, _ nameOfTheVariable: String ) )