Install Emacs 23. From apt-get or download for osx.
apt-get install emacs
-or-
http://emacsformacosx.com/
Install ELPA [http://tromey.com/elpa/install.html]:
M-x ielm [to fire up the emacs lisp interpreter]
Paste and run the following to install ELPA.
(let ((buffer (url-retrieve-synchronously
"http://tromey.com/elpa/package-install.el)))
(save-excursion
(set-buffer buffer)
(goto-char (point-min))
(re-search-forward "^$" nil 'move)
(eval-region (point) (point-max))
(kill-buffer (current-buffer))))
Install swank-clojure with ELPA:
M-x package-list-packages
Scroll down to swank-clojure and press i.
Press x to start installation.
Close emacs with C-x C-c.
Run swank-clojure with slime and let swank-clojure install it's dependencies:
Start emacs.
M-x slime
Answer yes to have swank-clojure install deps.
Bradford does a good job explaining how to install leiningen in this post so go with that. Once it's installed you can get your first emacs/slime/clojure repl like this:
> mkdir ~/tmp/
> cd ~/tmp/
> lein new test_clojure_repl
> cd test_clojure_repl
> lein deps
Start slime with all the leiningen default dependencies:
Start emacs.
M-x swank-clojure-project
Press enter to choose current directory.
You should now have a nice clojure/clojure-contrib repl.