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

What is underneath a Scala program?


A Scala program is a tree of nested definitions. A definition may start with a keyword, definition's name, a classifier, and if it's a concrete definition, then also an entity to which that definition is bound. So the syntax is regular, just like any other programming language has keyword/name/classifier/bound-entity. Let's take an example. We'll use Scala REPL to see how a simple Scala program is built. For that, let's import a Scala package named universe:

scala> import scala.reflect.runtime.universe._ 
import scala.reflect.runtime.universe._ 

This import clause brings all the definitions within the universe package in scope. It means that the required functions we are going to use are in scope, and available for us to use. Then we'll use a reify method, which returns an Expr to construct tree out of our simple Scala program expression. We passed a Scala class to our reify method. Let's pretend that a Scala class encapsulates some members like a value...