Book Image

Learning Scala Programming

By : Vikash Sharma
Book Image

Learning Scala Programming

By: Vikash Sharma

Overview of this book

Scala is a general-purpose programming language that supports both functional and object-oriented programming paradigms. Due to its concise design and versatility, Scala's applications have been extended to a wide variety of fields such as data science and cluster computing. You will learn to write highly scalable, concurrent, and testable programs to meet everyday software requirements. We will begin by understanding the language basics, syntax, core data types, literals, variables, and more. From here you will be introduced to data structures with Scala and you will learn to work with higher-order functions. Scala's powerful collections framework will help you get the best out of immutable data structures and utilize them effectively. You will then be introduced to concepts such as pattern matching, case classes, and functional programming features. From here, you will learn to work with Scala's object-oriented features. Going forward, you will learn about asynchronous and reactive programming with Scala, where you will be introduced to the Akka framework. Finally, you will learn the interoperability of Scala and Java. After reading this book, you'll be well versed with this language and its features, and you will be able to write scalable, concurrent, and reactive programs in Scala.
Table of Contents (21 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Option type


Option is one of the type constructors that Scala provides. The question arises, what's a type constructor? The answer is simple; it lets you construct a type. We'll take two statements:

  1. Option is a type constructor
  2. Option[Int] is a type

Let's discuss these in detail. When I say Foo is a type constructor, it means that Foo expects you to provide a particular type in the form of a parameter. It looks like Foo[T], where T is an actual type. We call them type parameters and we'll talk about them in the following few sections.

In the second statement, we saw that we gave an Int type to our Option type constructor in brackets and it formed a type. If you try this in the Scala REPL, it'll tell you exactly the same thing we discussed:

scala> val a: Option = Some(1) 
<console>:11: error: class Option takes type parameters 
       val a: Option = Some(1) 
 
scala> val a: Option[Int] = Some(1) 
a: Option[Int] = Some(1) 

In simple words, the Option[T] type represents an optional value...