2. Data Types and Immutability

Overview

In this chapter, we start by discovering the concept of immutability and its relevance in modern programs. We then examine simple data types such as strings, numbers and booleans, highlighting subtle differences in different environments like Clojure and ClojureScript. After a first exercise, we move on to more elaborated data types with collections such as lists, vectors, maps and sets, learning along the way which to use in different situations. After touching on the collection and sequence abstractions, we learn new techniques for working with nested data structures, before finally moving on to the final activity: implementing our very own in-memory database.

By the end of this chapter, you will be able to work with the commonly used data types in Clojure.