Setting up Clojurescript is fully described over at the Clojurescript Quick Start. What I am doing here is just reorganizing and rewriting to make things a bit more clear to someone that thinks like I do. While I was setting up clojurscript, I missed a couple of things as I was going along. So I thought it might be useful to others to go through the process for others. I work on Linux, and this method will work there. I suspect very strongly that it will work on OSX as well.

Download Clojurescript

First and foremost download Clojurescript as below.

$ git clone https://github.com/clojure/clojurescript

Yes, you need to go ahead and do the git clone. Clojurescript is moving forward rapidly and will be for the foreseeable future. You are going to be updating the repo on a regular basis. So go ahead and clone it. I suggest you put in whatever working directory you use for projects. I tend to keep my projects in $HOME/workspace, and that is where Clojurescript lives on my box. This works out rather well because I expect to be contributing back. Hopefully, you will too.

Bootstrapping

You can bootstrap everything by running the bootstrap script in the Clojurescript directory.

$ ./script/bootstrap
Fetching Clojure...
Fetching Google Closure Library...
Fetching Google Closure Compiler...
Building goog.jar...
Copying closure/compiler/compiler.jar to lib/...

It will pull down all the dependencies for Clojurescript. Note that Clojurescript relies on Clojure 1.3.0beta1 (at the time of this writing). It’s very probable that you are thinking about using Clojurescript as the front end to a project that uses Clojure as a back end. If that is the case, it’s probably best to base your back end project on Clojure 1.3.0beta1 or whatever happens to be the current version of Clojure that Clojure script uses.

Setup

If everything went well, the next thing we need to do is to setup the CLOJURESCRIPT_HOME env variable. This should point to where you installed Clojurescript. If you remember, I put my Clojurescript in $HOME/workspace/clojurescript and that’s where my CLOJURESCRIPT_HOME points.

$ export CLOJURESCRIPT_HOME=$HOME/

Of course, replace with actual location of your clojurescript repo.

Setting up the Paths

Finally, we want to set up the paths. You can either set your system PATH env variable to include both $CLOJURESCRIPT_HOME/script and $CLOJURESCRIPT_HOME/bin or you can symlink the cljsc and repl scripts to a location already in your bin directory. So you might do

$ export PATH=$PATH:$CLOJURESCRIPT_HOME/bin:$CLOJURESCRIPT_HOME/script

For putting those two in your path. Or you might do

$ ln -s $CLOJURESCRIPT_HOME/bin/cljsc $HOME/bin/
$ ln -s $CLOJURESCRIPT_HOME/script/repljs $HOME/bin/

As you might imagine, I have $HOME/bin already in my path. Either one works just fine, so it’s up to you. What you do not want to do is copy those scripts into locations in your PATH. Remember those scripts are going to change.

Try it Out

So let’s try it out. Run the reply; you should see something that looks like this.

$ repljs
#'user/jse
"Type: " :cljs/quit " to quit"
ClojureScript:cljs.user>

If you do, then WOOT! You are golden. If you don’t, then you probably forgot a step or did something wrong (or something fundamental has changed since I wrote this). Go back and take a look and see what went wrong.

Compiling Clojurscript

Having a repl is pretty impressive, and you are going to use it, but what you want to do is integrate it into your project. At the moment how you do, that is going to vary a lot depending on your project. However, in general here are two ways to do that. The first is to use the repl; the second is to run cljsc. I tend to use the cljsc script because I can stick it in a script.

I am building a project in Google App Engine using appengine-magic. I would love to have a compiler built into leiningen. However, there are no lein plugins for clojurescript yet. So I have a little shell script the runs in the root of the project. That shell script does the following.

$ cljsc ./src '{:optimizations :advanced :output-dir "war/js" :output-to "war/js/myprojectname.js"}'

That will do the whole program compilation over all your cljs files. As soon as we get some lein goodness, I will be migrating to that. I like an integrated build system quite a lot. ⤧  Next post Building an Application with ClojureScript and the Closure Library ⤧  Previous post An Introduction to Erlang