Professional Clojure

INTRODUCTION

WHAT IS CLOJURE?

Clojure is a dynamic, general-purpose programming language, combining the approachability and interactive development of a scripting language with an efficient and robust infrastructure for multithreaded programming. Clojure is a compiled language, yet remains completely dynamic—every feature supported by Clojure is supported at runtime. Clojure provides easy access to the Java frameworks, with optional type hints and type inference, to ensure that calls to Java can avoid reflection.

Clojure is a dialect of Lisp, and shares with Lisp the code-as-data philosophy and a powerful macro system. Clojure is predominantly a functional programming language, and features a rich set of immutable, persistent data structures. When mutable state is needed, Clojure offers a software transactional memory system and reactive Agent system that ensure clean, correct, multithreaded designs.

—Rich Hickey, author of Clojure

This quote from Rich Hickey, the creator of Clojure, captures what Clojure is. Many people equate Clojure with functional programming, but much like Lisp, its predecessor, it's a general-purpose language that will support you no matter what paradigm you decide to program in.

Clojure is, however, very opinionated and offers great support for programming in a functional manner, with its focus on immutable values and persistent data structures. You may be surprised to know that Clojure also offers the ability to do object-oriented programming, which ...