Book Image

The Clojure Workshop

By : Joseph Fahey, Thomas Haratyk, Scott McCaughie, Yehonathan Sharvit, Konrad Szydlo
Book Image

The Clojure Workshop

By: Joseph Fahey, Thomas Haratyk, Scott McCaughie, Yehonathan Sharvit, Konrad Szydlo

Overview of this book

The Clojure Workshop is a step-by-step guide to Clojure and ClojureScript, designed to quickly get you up and running as a confident, knowledgeable developer. Because of the functional nature of the language, Clojure programming is quite different to what many developers will have experienced. As hosted languages, Clojure and ClojureScript can also be daunting for newcomers because of complexities in the tooling and the challenge of interacting with the host platforms. To help you overcome these barriers, this book adopts a practical approach. Every chapter is centered around building something. As you progress through the book, you will progressively develop the 'muscle memory' that will make you a productive Clojure programmer, and help you see the world through the concepts of functional programming. You will also gain familiarity with common idioms and patterns, as well as exposure to some of the most widely used libraries. Unlike many Clojure books, this Workshop will include significant coverage of both Clojure and ClojureScript. This makes it useful no matter your goal or preferred platform, and provides a fresh perspective on the hosted nature of the language. By the end of this book, you'll have the knowledge, skills and confidence to creatively tackle your own ambitious projects with Clojure and ClojureScript.
Table of Contents (17 chapters)
Free Chapter
2
2. Data Types and Immutability

Introduction

In the previous chapter, we learned how to create a Leiningen project. A project gives a structure for organizing our code. We structure our project around namespaces. We created new namespaces and we imported external Clojure libraries in order to use them in our code.

Now that you are familiar with using namespaces and creating Clojure projects, it is time to become more comfortable with working on projects that use Java and JavaScript.

As we learned in Chapter 1, Hello REPL!, Clojure compiles to Java bytecode and operates on the Java Virtual Machine (JVM). The JVM is a host platform. Any programming language that compiles to Java bytecode can run on the JVM. Because Clojure compiles to Java bytecode and runs on the JVM, we call it a hosted language. Java dates from the 1990s and is now one of the most popular backend languages. We can leverage existing Java libraries instead of writing a lot of code on our own. This helps us deliver new features faster.

As...