The most effective way to break applications is to create GOD classes. Those are classes that keep track of a lot of information and have several responsibilities. One code change will most likely affect other parts of the class and therefore indirectly all other classes that use it. That in turn leads to an even … Read more
It means that you should put new code in new classes/modules. Existing code should be modified only for bug fixing. New classes can reuse existing code via inheritance. Open/closed principle is intended to mitigate risk when introducing new functionality. Since you don’t modify existing code you can be assured that it wouldn’t be broken. It … Read more
According to the very popular WWDC 2015 talk Protocol Oriented Programming in Swift (video, transcript), Swift provides a number of features that make structs better than classes in many circumstances. Structs are preferable if they are relatively small and copiable because copying is way safer than having multiple references to the same instance as happens … Read more
What is an example of the Liskov Substitution Principle?