Using CS with Java Rhino

This page details trials and tribulations of getting CoffeeScript to run on Java (via the Rhino JavaScript engine).

There is this old-ish clojure based route, not tried it and its more than a year old now.

Issues/Features/Opportunities:

• there is a 64k byte code limit in Java for compiled code, and as both the full/minimised coffee-script.js and the individual files break this when compiled, you have to go down the interpreted javascript route, which means optimisation level -1 (ie its slower than it could be).
• the Rhino engine has no require facility, but the library RingoJS is a way to get some CommonsJS facilities.
• using RingoJS requires a newer/full Rhino engine - see here (1.7 as of writing, April 2012).
• using CoffeeScript = require('coffee-script.js') // where this is the full/minimised version, loads ok but does not seem to expose a compile or eval method. Presume its due to how its expecting to be called and where its attaching things...

I have had some success doing the following:

• using Rhino 1.7 (see above)
• with RingoJS (also above)

Then this Java code:

    RingoRunner runner = new RingoRunner();
    String[] config = {
            "-o", "-1",
            "-m", "js",
            "-m", "js/coffee-script",
            "-m", "js/commonjs-stubs",
            "hello.js"};
    runner.run(config);

and this JS code (hello.js):

var CoffeeScript = require('coffee-script');

var compiled_cs = CoffeeScript.compile("print 'cs-boo'");
eval(compiled_cs);

Works!