nREPL middlewares for CIDER

cider, clojure, nrepl, nrepl-middleware


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A collection of nREPL middleware designed to enhance CIDER.

If you're just a user trying to get started with CIDER, then you probably don't want to read this. You should follow the steps in CIDER's Readme instead.

If you're trying to use cider-nrepl for some other purpose, the sections below outline how to include it in a project.



cider-nrepl supports only Clojure(Script) 1.7+ and Java 7+.

Leiningen users will need to have version 2.5.2 or newer installed.

Via Leiningen

Use the convenient plugin for defaults, either in your project's project.clj file or in the :user profile in ~/.lein/profiles.clj.

:plugins [[cider/cider-nrepl "0.14.0"]]

A minimal profiles.clj for CIDER would be:

{:user {:plugins [[cider/cider-nrepl "0.14.0"]]}}

Or (if you know what you're doing) add cider-nrepl to your :dev :dependencies vector plus specific middleware to :nrepl-middleware under :repl-options.

:dependencies [[cider/cider-nrepl "0.14.0"]]
:repl-options {:nrepl-middleware

Note that you should use a cider-nrepl version compatible with your CIDER. Generally, if you're using CIDER 0.x.y you should be using cider-nrepl 0.x.y, if you're using CIDER 0.x.y-SNAPSHOT, you should be using cider-nrepl 0.x.y-SNAPSHOT, etc.

Via Boot

Boot users can configure the tool to include the middleware automatically in all of their projects using a ~/.boot/profile.boot file like so:

(require 'boot.repl)

(swap! boot.repl/*default-dependencies*
       concat '[[cider/cider-nrepl "0.14.0"]])

(swap! boot.repl/*default-middleware*
       conj 'cider.nrepl/cider-middleware)

For more information visit boot-clj wiki.

Via embedding nREPL in your app

If you're embedding nREPL in your application you'll have to start the server with CIDER's own nREPL handler.

(ns my-app
  (:require [ :as nrepl-server]
            [cider.nrepl :refer (cider-nrepl-handler)]))

(defn -main
  (nrepl-server/start-server :port 7888 :handler cider-nrepl-handler))

With JBoss AS/JBoss EAP/WildFly

Using the advanced features of the info middleware with one of the JBoss application servers requires a tweak, since JBoss modules prevent modifications to AppClassLoader (usually the highest modifiable classloader) from being seen by application code. To work around this, run the following code from within your application to mark that classloader as unmodifiable, and cause the lower level clojure.lang.DynamicClassLoader to be used instead. This code must execute prior to loading the cider-nrepl middleware. Note that this is only if you are deploying a standard WAR file to the application server directly. If you are using Immutant (1.x or 2.x), you won't need to do this.

(require '[dynapath.dynamic-classpath :as cp])

(extend sun.misc.Launcher$AppClassLoader
  (assoc cp/base-readable-addable-classpath
    :classpath-urls #(seq (.getURLs %))
    :can-add? (constantly false)))

Supplied nREPL middleware

Middleware Op(s) Description
wrap-apropos apropos Pattern search for symbols and documentation.
wrap-classpath classpath Java classpath.
wrap-complete complete Simple completion. Supports both Clojure & ClojureScript.
wrap-debug init-debugger/debug-input Establish a channel for cider-debug commands, use it to get debug input, and also wrap the eval op.
wrap-format format-(code/edn) Code and data formatting.
wrap-info info/eldoc File/line, arglists, docstrings and other metadata for vars.
wrap-inspect inspect-(start/refresh/pop/push/reset) Inspect a Clojure expression.
wrap-macroexpand macroexpand/macroexpand-1/macroexpand-all/macroexpand-step Macroexpand a Clojure form.
wrap-ns ns-list/ns-vars/ns-path/ns-load-all Namespace browsing & loading.
wrap-pprint Adds pretty-printing support to code evaluation. It also installs a dummy pprint-middleware op. Thus wrap-pprint is discoverable through the describe op.
wrap-pprint-fn Provides a common pretty-printing interface for other middlewares that need to perform customisable pretty-printing.
wrap-refresh refresh/refresh-all/refresh-clear Code reloading.
wrap-resource resource Return resource path.
wrap-stacktrace stacktrace Cause and stacktrace analysis for exceptions.
wrap-test test/retest/test-stacktrace Test execution, reporting, and inspection.
wrap-trace toggle-trace-var/toggle-trace-ns Toggle tracing of a given var or ns.
wrap-out Echo the server's output stream to client sessions.
wrap-undef undef Undefine a var.
wrap-version cider-version The CIDER-nREPL version map.

Release policy

We’re following SemVer (as much as one can be following it when the major version is 0). At this point bumps of the minor (second) version number are considered major releases and always include new features or significant changes to existing features. API compatibility between major releases is not a (big) concern (although we try to break the API rarely and only for a good reason).

The development cycle for the next major release starts immediately after the previous one has been shipped. Bugfix/point releases (if any) address only serious bugs and never contain new features.

The versions of CIDER and cider-nrepl are always kept in sync. If you're tracking the master branch of CIDER, you should also be tracking the master branch of cider-nrepl.



For questions, suggestions and support refer to our official mailing list or the Freenode channel #clojure-emacs. Please, don't report issues there, as this makes them harder to track.


Report issues and suggest features and improvements on the GitHub issue tracker. Don't ask questions on the issue tracker - the mailing list and the IRC channel are the places for questions.


Patches under any form are always welcome! GitHub pull requests are even better! :-)

Before submitting a patch or a pull request make sure all tests are passing and that your patch is in line with the contribution guidelines.

Working with mranderson (inlining dependencies)

mranderson is used to avoid classpath collisions.

To work with mranderson the first thing to do is:

lein do clean, source-deps :project-prefix cider.inlined-deps

This creates the munged local dependencies in target/srcdeps directory.

After that you can run your tests or your REPL with:

lein with-profile +plugin.mranderson/config repl
lein with-profile +plugin.mranderson/config test

Note the + sign before the leiningen profile. For this leiningen profile to work you need leiningen version 2.5.0+! If you want to use mranderson while developing locally with the REPL the source has to be modified in the target/srcdeps directory. When you want to release locally:

lein with-profile plugin.mranderson/config install

Release to clojars:

lein with-profile plugin.mranderson/config deploy clojars

Or you can use the very sophisticated script to clean, inline, test and run an end target like install or deploy:

./ install
./ deploy clojars cleans, runs source-deps with the right parameters, runs the tests and then runs the provided lein target.

Hall of Fame

Special credit goes to the following people for their contributions:

And a big thanks to all other contributors who have helped so far.

Let's also acknowledge some of the projects leveraged by cider-nrepl:


Copyright © 2013-2016 Bozhidar Batsov

Distributed under the Eclipse Public License, the same as Clojure.