Book Image

Learn Scala Programming

By : Slava Schmidt
Book Image

Learn Scala Programming

By: Slava Schmidt

Overview of this book

The second version of Scala has undergone multiple changes to support features and library implementations. Scala 2.13, with its main focus on modularizing the standard library and simplifying collections, brings with it a host of updates. Learn Scala Programming addresses both technical and architectural changes to the redesigned standard library and collections, along with covering in-depth type systems and first-level support for functions. You will discover how to leverage implicits as a primary mechanism for building type classes and look at different ways to test Scala code. You will also learn about abstract building blocks used in functional programming, giving you sufficient understanding to pick and use any existing functional programming library out there. In the concluding chapters, you will explore reactive programming by covering the Akka framework and reactive streams. By the end of this book, you will have built microservices and learned to implement them with the Scala and Lagom framework.
Table of Contents (19 chapters)

Familiarizing Yourself with Basic Monads

In the previous chapter, we got to know Functors, an abstraction that gives the map method the effects defined in the standard library. Looking back at Chapter 6, Exploring Built-In Effects, there is still something missing here—the source of the flatMap method, which all standard effects also have.

In this chapter, we will finally meet the concept of a monad, the structure that defines flatMap. To learn about this function inside and out, we'll implement four different monads.

By the end of this chapter, you'll be familiar with the following topics:

  • Abstracting a monad and its properties
  • Implementing monads for standard effects
  • The implementation and applicability of the following basic monads:
    • Id
    • State
    • Reader
    • Writer