Install clojure-mode either from git or via Marmalade using Emacs' package manager.

Open or create a Clojure .clj file, and you should find that clojure-mode enabled since built-in functions and forms are syntax-highlighted.

There are multiple approaches for interacting with a live Clojure process:

• SLIME and Swank Clojure: a rich, complex mode that provides various commands to communicate with an external Clojure instance via a socket.
• inferior-lisp: a simple mode that will start a Clojure instance as a subprocess and then communicates with its REPL via stdin/stdout pipes.

In both cases, you need to launch a Clojure subprocess. This is most commonly done using a tool such as Leiningen.

SLIME and Swank Clojure

Invoke M-x clojure-jack-in once Leiningen is installed to begin a Slime session for the current project.

The most commonly-used key bindings are C-c C-k to compile the current file, M-. to jump to a definition, and C-c M-p to change the namespace of the repl session.

For more key bindings and other details see the swank-clojure readme.

inferior-lisp

The simplest way to interact with Clojure is to launch a subprocess by invoking M-x run-lisp (C-c C-z) from a clojure buffer.

Use C-x C-e at the end of an expression to evaluate it, showing the result in the inferior-lisp buffer. C-c C-l will load the current file. C-M-x can evaluate a whole def form.

If you don't use Leiningen you'll need to customize the command that launches a Clojure REPL. You can use an absolute path, or a relative path that will be interpreted relative to the current directory in emacs. M-x describe-variable inferior-lisp-program with one of the following:

• java -cp path/to/clojure.jar clojure.main for a basic repl (no rlwrap/jline needed)
• lein repl for a Leiningen project
• cake repl for a Cake project
• mvn clojure:repl for a Maven project
• script/repl for the labrepl tutorial project

Automated VM Setup

If you don't mind working in a virtual machine, you can get a fully-automated VM set up with Emacs configured using Slime and Swank-Clojure using Vagrant: https://github.com/Seajure/emacs-clojure-vagrant