POP

POP encourages us to develop protocols and extend them instead of classes and inheritance. POP is new in the Objective-C and Swift development community, but what it provides is not very different from the concept of Abstract classes in languages such as Java and C#, and pure-virtual functions in C++.

In Swift, classes, structs, and enumerations can conform to protocols. This makes protocols more usable because inheritance does not work for structs and enumerations.

POP paradigms

In this section, we will explore POP paradigms. To start with, we will look at an example:

protocol UserProtocol { 
    func greet(name: String) -> String 
    func login(username: String, password: String) -> Bool 
} 

This protocol defines two functions to be implemented by the...