RubyCocoa is a Mac OS X framework that provides a bridge between the Ruby and the Objective-C programming languages, allowing the user to manipulate Objective-C objects from Ruby, and vice versa. It makes it possible to write a Cocoa application completely in Ruby as well as to write an application that mixes Ruby and Objective-C code. An Apple project called MacRuby was under development to replace RubyCocoa in 2008. A proprietary spin-off called RubyMotion was subsequently released in 2012, available for iOS, OS X and Android.
Some useful applications of RubyCocoa are exploration of a Cocoa object's features with irb interactively, prototyping of a Cocoa application, writing a Cocoa application that combines the features of Ruby and Objective-C and wrapping Mac OS X's native GUI for a Ruby script.
RubyCocoa is free software, released under both the Ruby License and the LGPL.