Ruby is a dynamic, open source programming language with a focus on simplicity and productivity. It´s a scripting language for reflexive (intensive use of program metadata) and object-oriented programming.
The Ruby Generator is focused on its prototyping speed. As it is a dynamic language, once it is generated it runs immediately, unlike the other languages which, in requiring compilation, imply a slower process in the end result.
Ruby Generator is a free license generator.
Read more information about it in the Ruby Generator Manual