Ruby CoffeeScript is a bridge to the official CoffeeScript compiler.

CoffeeScript.compile File.read("script.coffee")

gem install coffee-script

Note: This compiler library has replaced the original CoffeeScript compiler that was written in Ruby.

This library depends on the coffee-script-source gem which is updated any time a new version of CoffeeScript is released. (The coffee-script-source gem's version number is synced with each official CoffeeScript release.) This way you can build against different versions of CoffeeScript by requiring the correct version of the coffee-script-source gem.

In addition, you can use this library with unreleased versions of CoffeeScript by setting the COFFEESCRIPT_SOURCE_PATH environment variable:

export COFFEESCRIPT_SOURCE_PATH=/path/to/coffee-script/extras/coffee-script.js

The json library is also required but is not explicitly stated as a gem dependency. If you're on Ruby 1.8 you'll need to install the json or json_pure gem. On Ruby 1.9, json is included in the standard library.

The ExecJS library is used to automatically choose the best JavaScript engine for your platform. Check out its README for a complete list of supported engines.