Clojure
Overview
Clojure is a modern dialect of the Lisp programming language that emphasizes functional programming and is designed to run on the Java virtual machine (JVM), the Common Language Runtime (.NET), and JavaScript engines. It was created by Rich Hickey and first released in 2007. Clojure treats code as data and has a macro system, and it provides immutable data structures and a software transactional memory system for concurrency.
History
Rich Hickey began developing Clojure in 2005 as a pragmatic Lisp that could leverage existing libraries and platforms while introducing modern concurrency and functional programming facilities. The first public release was in 2007, and the language quickly gained attention within the Java and Lisp communities. In 2013, Clojure was added to the project hosting site GitHub. Its ecosystem includes a package manager (Leiningen / tools.deps) and a growing library of community projects.
Features
- Functional core: Clojure encourages a functional style, with persistent, immutable data structures such as vectors, maps, sets, and lists.
- Concurrency support: Built-in mechanisms like atoms, refs, agents, and software transactional memory (STM) simplify safe concurrent programming.
- Lisp heritage: The syntax is based on S-expressions, and the language supports metaprogramming through macros.
- JVM interop: Clojure code compiles to JVM bytecode and can directly call Java libraries and frameworks.
- Hosted platform: In addition to the JVM, implementations exist for the .NET Common Language Runtime (ClojureCLR) and JavaScript (ClojureScript), allowing code reuse across environments.
- REPL-driven development: The interactive read–eval–print loop (REPL) enables rapid prototyping and iterative design.