Let&#39;s say that I have the following protocol:

    protocol Identifiable {
        var id: Int {get}
        var name: String {get}
    }

And that I have the following structs:

    struct A: Identifiable {
        var id: Int
        var name: String
    }
    
    struct B: Identifiable {
        var id: Int
        var name: String
    }

As you can see, I had to &#39;conform&#39; to the Identifiable protocol in struct A and struct B. But imagine if I had N more structs that needs to conform to this protocol... I don&#39;t want to &#39;copy/paste&#39; the conformance (var id: Int, var name: String)

So I create a **protocol extension**:

    extension Identifiable {
        var id: Int {
            return 0
        }
        
        var name: String {
            return &quot;default&quot;
        }
    }

With this extension now I can create a struct that conforms to the Identifiable protocol without having to implement both properties:

    struct C: Identifiable {
    
    }

Now the problem is that I can&#39;t set a value to the id property or the name property:

    var c: C = C()
    c.id = 12 // Cannot assign to property: &#39;id&#39; is a get-only property

This happens because in the Identifiable protocol, id and name are only gettable. Now if I change the id and name properties to **{get set}** I get the following error:

*Type &#39;C&#39; does not conform to protocol &#39;Identifiable&#39;*

This error happens because I haven&#39;t implemented a setter in the protocol extension... So I change the protocol extension:

    extension Identifiable {
        var id: Int {
            get {
                return 0
            }
            
            set {
                
            }
        }
        
        var name: String {
            get {
                return &quot;default&quot;
            }
            
            set {
                
            }
        }
    }

Now the error goes away but if I set a new value to id or name, it gets the default value (getter). Of course, **the setter is empty**.

My question is:
**What piece of code do I have to put inside the setter?** Because if I add *self.id = newValue* it crashes (recursive).

Thanks in advance.

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Swift - Protocol extensions - Property default values