Chapter 10. Advanced Functional Programming

"Like punning, programming is a play on words."

– Alan Peris

You're a developer, right? Think of a scenario where you're asked to write some software that has certain entities. Take a look at the following:

Animal         |      Food 

We have the Animal and Food entities. We're working on an automated system that serves food to animals in a zoo. Suppose we're going to write a function which lets two animals share their food. It expects two animal objects, food, and then does the job. The function looks like this:

def serveSharedMeal(
    animalOne: Animal, 
    animalTwo: Animal, 
    meal: Food) = ??? 
//don't care about the implementation 

So far, everything's fine, right? Let's introduce two animals now. We have two animal subclasses named Lion and Deer. Our simple function takes two animal instances and shares the meal instance among them. Now, you might wonder what happens when we pass instances of Lion and Deer; what might be the consequences?...