Book Image

Professional Scala

By : Mads Hartmann, Ruslan Shevchenko
Book Image

Professional Scala

By: Mads Hartmann, Ruslan Shevchenko

Overview of this book

This book teaches you how to build and contribute to Scala programs, recognizing common patterns and techniques used with the language. You’ll learn how to write concise, functional code with Scala. After an introduction to core concepts, syntax, and writing example applications with scalac, you’ll learn about the Scala Collections API and how the language handles type safety via static types out-of-the-box. You’ll then learn about advanced functional programming patterns, and how you can write your own Domain Specific Languages (DSLs). By the end of the book, you’ll be equipped with the skills you need to successfully build smart, efficient applications in Scala that can be compiled to the JVM.
Table of Contents (12 chapters)

Ad Hoc Polymorphism and Type Classes

In this section, we'll be exploring ad hoc polymorphism, but through the usage of type classes.

Types of Polymorphism

In computer science, polymorphism is the provision of a single interface to entities of different types. Polymorphism consists of three types: subtyping, parametric polymorphism, and ad hoc polymorphism.

Subtyping enables polymorphism by having different implementations of the same method (but keeping the interface) in the different subclasses. Parametric polymorphism enables polymorphism by allowing code to be written without the mention of a specific type. For example, when you operate over a generic List, you're applying parametric polymorphism. Ad hoc polymorphism enables polymorphism by allowing different and heterogeneous implementations depending on specified types. Method overloading is an example of ad hoc polymorphism.

Type Classes

Type classes are a construct that enable ad hoc polymorphism. They originally appeared in Haskell...