ooPIC interpreter software is now open source under GPLv3

(from http://www.oopic.com/)

OOPic is an acronym for Object-Oriented PIC

The first operating system for Microchip PICs to use an Object-Oriented approach to hardware control. 

The concept behind OOPic is straight forward.  Use preprogrammed multitasking Objects from a library of highly optimized Objects to do all the work of interacting with the hardware.  Then write small scripts in Basic, C, or Java syntax styles to control the Objects.  During operation, the Objects run continuously and simultaneously in the background while the scripts run in the foreground telling the objects what to do.  Every aspect of the Objects can be controlled by the scripts as the Object do their work with the hardware.  The OOPic Object library contains Object that know how to interact with the most popular sensors and drive systems around which make the OOPic ideally suited for robotics of any kind.  
A list of Object can be found at: http://www.oopic.com/objlist.htm

Another unique feature of OOPic is the Virtual Circuits capability.  Virtual Circuits pass data around in the background so that your script doesn’t have to.  Virtual circuits can handle the processing required for speed control, time-out events, limit switches, emergency breaking, and a whole myriad of other functions. In several cases, entire applications can be built as pure Virtual Circuits.
A simple example of Virtual Circuits can be found at: http://www.oopic.com/virtcirc.htm

OOPic programming is simple and straight forward

Within the OOPic IDE programming environment, you can choose to write in Basic, C or Java syntax for your scripts. As with its software counter parts, OOPic shares the Object-oriented concepts used in Visual Basic, C++ and Java with a few differences to handle embedded controllers.  The IDE runs on the Microsoft Windows operating systems. It is, and always will be, available for download, free of charge, at http://www.oopic.com/dload.htm.  After creating the programs, a single keystroke sends the program from the PC to the OOPic.  The OOPic will start running the new program as soon as the PC is finished downloading and each time the power is turned on.