Ripley is a programming language that is somewhere between Forth and Postscript in terms of syntax. It is written in Ruby. There are several interesting techniques that were used to build Ripley including code generation for the individual language ops,
Create a text editor for computer programmers. Use ruby as underlying system and write core code in C. Support at least inline debugging as well as common features such as colored keywords.
Breeze is a build and test automation framework for software developers. It is written in Ruby and can be extended to include tasks that interact with other tools such as source code repositories, compilers, test frameworks, and installers.
Generate C++ header files from cpp files. Inspired by javadoc, and doxygen style source commenting. No need to maintain two seperate files to represent one class. Create and keep your headers up-to-date with your cpp files with little effort.
The Voodoo compiler is an implementation of the Voodoo programming language. It provides both a stand-alone compiler executable and a Ruby API for generating code for target platforms.
The mywaves utilities project provides open source utilities and documentation, including scripts to generate RSS feeds for mywaves.com to find videos on a web site.