Running REPLs

As of 0.0-2655 REPLs have changed significantly enough that many existing third party REPLs and REPL launchers no longer work. While they are likely to be updated in the near future the following demonstrates how to run REPLs directly without using anything more than Leiningen itself.

All that is required is to make a REPL runner .clj file. For example if your cljsbuild entry looks like the following:

{:id "dev"
 :source-paths ["src"]
 :compiler {
   :output-to "hello_world.js"
   :output-dir "out"
   :optimizations :none
   :cache-analysis true                
   :source-map true}}

Then your node_repl.clj file should look like the following:

(require
  '[cljs.repl :as repl]
  '[cljs.repl.node :as node])

(repl/repl* (node/repl-env)
  {:output-dir "out"
   :optimizations :none
   :cache-analysis true                
   :source-map true})

You can then run the Node.js REPL against your build with the following:

lein trampoline run -m clojure.main node_repl.clj

For better behavior at the command line installed rlwrap (under OS X easily done with brew), then:

rlwrap lein trampoline run -m clojure.main node_repl.clj

Browser REPL

Browser REPL is almost exactly the same setting up a Node.js REPL.

Your browser_repl.clj should look like the following:

(require
  '[cljs.repl :as repl]
  '[cljs.repl.browser :as browser])

(repl/repl* (browser/repl-env)
  {:output-dir "out"
   :optimizations :none
   :cache-analysis true                
   :source-map true})

Remember that you must change your source file to include the browser REPL:

(ns hello-world.core
  (:require [clojure.browser.repl :as repl]))

(repl/connect "http://localhost:9000/repl")

(enable-console-print!)

(println "Hello world!")

Then build your project:

lein cljsbuild once hello-world

Now you can launch your browser REPL:

lein trampoline run -m clojure.main browser_repl.clj