REPL-y: A fitter, happier, more productive REPL for Clojure.
Clojure Java Shell
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A fitter, happier, more productive REPL for Clojure.

Improvements over the existing REPL that comes in clojure.jar

  • A number of readline commands, some not available in earlier JLine versions:
    • navigation to the start/end of lines, and forward/back by word
    • history navigation and search
    • and much much more
  • CTRL-C:
    • kills the currently running command, breaks out of infinite loops, etc.
    • doesn't bail out of the process - stops interruption-friendly operations
  • Code completion for:
    • Clojure vars and namespaces
    • Clojure namespace-qualified vars
    • Java classes, packages
    • Java package-qualified classes, static methods
  • ClojureDocs support via a clojuredocs command
  • Optional nREPL integration


REPLy is now part of leiningen, as of the 2.x preview series. It's definitely your best bet for installation and Clojure development in general.

And here's how to get a standalone version up and running (assuming you have leiningen installed):

git clone
cd reply
lein deps, compile


The easiest way: use lein repl (for 2.x). Skip the rest if that's all you need.

Running lein trampoline run at the command line, in this project, will get you the latest stuff on master.

There are also example bin scripts that are currently just set up to work with Leiningen 1.x (2.x already contains REPLy, just not necessarily always the latest from master here). If you want additional stuff on the classpath, you can set $USER_CP. For instance:

USER_CP=`lein classpath` reply

Examples of fancy options:

Launch in nREPL mode:

$ reply

Standalone execution (no nREPL):

$ reply --standalone

Skip all the bells-and-whistles initialization and provide your own:

$ reply --skip-default-init -e '(println "OHAI WORLD")'

For details on the latest and greatest:

$ reply --help


If you're having problems, feel free to open an issue, but the following may help.

For keybinding issues, check out ~/.inputrc - you can mostly use the same specifications there as you can with normal readline applications like bash, but from time to time we do come across missing features that we then add to jline.

To get a very detailed look at what jline is doing under the hood, you can export JLINE_LOGGING=trace (or debug) before starting REPLy. There may be more output than you'd like, but this kind of output is especially helpful when debugging keybinding issues.

You can use the --standalone flag to rule out any nREPL-related questions, but I'm not aware of anyone using --standalone for other purposes. Please let me know if you are!


Thanks to the developers of Clojure, JLine, nREPL, clojure-complete, ClojureDocs, and clojuredocs-client, for their work on the excellent projects that this project depends upon.

Special thanks to 8th Light for allowing me to work on this during our open-source Friday afternoons.


Copyright (C) 2011-2012 Colin Jones

Distributed under the Eclipse Public License, the same as Clojure. See the LICENSE file for details.