如何快速在其他类中找到类实例名称？

Question

Imagine a situation that we have two classes like these:

class MyClass {
    func printInstanceName() {
        print(what?);
    }
}

class User {
    var firstObject: MyClass!
    var secondObject: MyClass!
}

I will instantiate an object of class User like this:

let user = User();
user.firstObject = MyClass()
user.secondObject = MyClass()

How should i implement the printInstanceName that the output of code below

user.firstObject.printInstanceName()
user.secondObject.printInstanceName()

be

firstObject
secondObject

The purpose of doing this is, i want to know from which instance of MyClass in User , printInstanceName is called!

Answer 1

You cant get property name from MyClass, only from User.

class MyClass { }

class User {
    var myObject: MyClass!
    
    func printInstanceName() {
        let mirror = Mirror(reflecting: self)
        for (label, value) in mirror.children {
            if type(of: value) == Optional<MyClass>.self {
                print(label!)
            }
        }
    }
}

let u = User()
u.printInstanceName()

Answer 2

Use String(describing: type(of: self)) to print the class name.

class MyClass {
    func printInstanceName() {
        print(String(describing: type(of: self)))
    }
}

Don't use force-unwrapped variables unnecessarily. You can create an init(myObject:) instead.

class User {
    var myObject: MyClass
    
    init(myObject: MyClass) {
        self.myObject = myObject
    }
}

Create User instance like,

let user = User(myObject: MyClass())
user.myObject.printInstanceName()

Answer 3

You can get variable name only in this way

class MyClass {
    func printInstanceNameIn(user: User) {
        let mirror = Mirror(reflecting: user)
        for (label, value) in mirror.children {
            if let value = value as? MyClass, value === self {
                print(label!)
            }
        }
    }
}

class User {
    var firstObject: MyClass!
    var secondObject: MyClass!
}

let u = User()
u.firstObject = MyClass()
u.secondObject = MyClass()
u.firstObject.printInstanceNameIn(user: u)

Answer 4

I know this is not what you're exactly looking for but it might helps:

    for child in Mirror(reflecting: user).children {
    print(child.label)
}