Over a year ago we had a post about how to build OS X GUI applications with Ruby and RubyCocoa. Since then, however, MacRuby has arrived on the scene. Not just the regular version of Ruby with some bindings to Cocoa, MacRuby is as native to OS X as JRuby is native to the JVM.

It's a significant development, then, that Apple has created a very in-depth tutorial called Developing Cocoa Applications Using MacRuby. It's very comprehensive. The tutorial introduces you to MacRuby, walks you through installation, demonstrates Objective-C bindings, and steps through using XCode and MacRuby to develop a simple GUI application. If you want to read a single tutorial and be able to develop a Mac GUI app with Ruby from start to finish, this is currently the tutorial to read.

That said, you might still appreciate our Ultimate List of RubyCocoa Tutorials, Tips, and Tools. There are 42 links there; many of which are still incredibly useful.