Created: 2008-12-16 17:15
Updated: 2016-06-19 02:56


An experimental implementation of the Ruby language on top of the Objective-J runtime / JavaScript.

It is currently very incomplete. Many language features and the vast majority of the standard library are not implemented.

Inspired by MacRuby (though far less cool or useful).


  • Objective-J and Cappuccino
  • Ruby (1.8?)
  • ParseTree gem
  • Narwhal (for "cappruby" command)



To see a simple example of the compiler in action run:

bin/ruby2objj TestApp/main.rb


cat TestApp/main.rb | bin/ruby2objj

The output can of course be concatenated to a file:

bin/ruby2objj TestApp/main.rb > TestApp/main.j


To run TestApp using the Rack server, ensure that the "Frameworks" directory contains the Cappuccino frameworks (assumes the Cappuccino tools are installed):

capp gen -f TestApp

Then run:


Command-line and Narwhal integration

To run the cappruby command line REPL make sure cappruby was installed via tusk, or you have added it's "bin" to your PATH.

~/git/cappruby $ cappruby
capprb> puts 'hello world'
hello world

Alternatively, run from within narwhal:

~/git/cappruby $ narwhal
> require("cappruby").run()
capprb> puts 'hello world'
hello world

Run simple Ruby files using Narwhal:

~/git/cappruby $ narwhal test.rb
hello world
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