Is there a way to declare protocol property as private? - swift

Question

I want to conform to a protocol, as well as to hide its conformed properties to be accessed (declare them as private).
Consider the following:
protocol P {
var value: String { get }
init(value: String)
}
class C: P {
var value: String
required init(value: String) {
self.value = value
}
}
I would create a C object:
let myObject = C(value: "Hello World")
myObject.value = "New Value"
Based on that I have 2 questions:
Now, if I tried to declare value as private:
private var value: String { get }
the compiler will throw an error:
'private' modifier cannot be used in protocols
with a fix suggestion to replace the private with internal.
How can I prevent value from being accessible by saying myObject.value? if there is no way, what's the reason of this limitation?

Answer 1

Conforming to
protocol P {
var value: String { get }
init(value: String)
}
requires a gettable property value with default access. If write access to the
property in the conforming class should be restricted to the class itself
then you can declare it as in Swift readonly external, readwrite internal property:
class C: P {
private(set) var value: String
required init(value: String) {
self.value = value
}
}
let myObject = C(value: "Hello World")
print(myObject.value) // OK
myObject.value = "New Value" // Error: Cannot assign to property: 'value' setter is inaccessible
And if the property should only be set in initializers then make it
a constant:
class C: P {
let value: String
required init(value: String) {
self.value = value
}
}
let myObject = C(value: "Hello World")
print(myObject.value) // OK
myObject.value = "New Value" // Error: Cannot assign to property: 'value' is a 'let' constant