Swift - class method which must be overridden by subclass

Question

Is there a standard way to make a \"pure virtual function\" in Swift, ie. one that must be overridden by every subclass, and which, if it is not, causes a c

Answer 1

Being new to iOS development, I'm not entirely sure when this was implemented, but one way to get the best of both worlds is to implement an extension for a protocol:

protocol ThingsToDo {
    func doThingOne()
}

extension ThingsToDo {
    func doThingTwo() { /* Define code here */}
}

class Person: ThingsToDo {
    func doThingOne() {
        // Already defined in extension
        doThingTwo()
        // Rest of code
    }
}

The extension is what allows you to have the default value for a function while the function in the regular protocol still provides a compile time error if not defined