After going through a lot of theory about monads, it would now be useful to go through some code that demonstrates how to implement and use the theoretical concepts, which real-world situations they are good for, and so on.
Let's now do something similar to what we did before, and show what a monad trait will look like in Scala. Before doing this, however, let's slightly change our functor definition:
trait Functor[T] { def map[Y](f: T => Y): Functor[Y]}
In the preceding code, instead of passing the element that will be mapped, we assume that the type that mixes Functor will have a way to pass it to the map implementation. We also changed the return type so that we can chain multiple functors using map. After we've done ...
