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)

Understanding types

The type of something is a summation of the information the compiler owns about this something. In the most general case, we're talking about the type of a variable; the knowledge of the compiler includes the methods that are available on this variable and the classes that the variable extends. A very convenient feature of Scala is that it tries to use type inference where possible, freeing the developer from the need to define types explicitly.

Let's take a structured look at Scala's type system, starting with a short recap of its basics.

Ways to create a type

There are four ways to define a type in Scala:

  • By using a literal to define a singleton type
  • By using the type keyword to define...