Build Smarter Robots with the Robot Vision Toolkit and RobotSee from EMGRobotics.
A free robotics toolkit with a simple programming language that is as easy as BASIC with the power of C. The toolkit lets you easily add computer vision, mind control, voice control, GPS support, and more to your robot using a very easy to learn simple programming language.
The RobotSee interpreter has always been open source, released under GPLv3.
You can find the source here: http://sourceforge.net/projects/robotseeintrptr/
I keep the repository up to date, and there are various other language extensions in the download. The interpreter can be built under Linux using the makefile in the tree root.