A simple implementation of the BASIC language, including various loop, subroutines and libraries, written by Marc-Oliver Ihm. It is not an interpreter but rather a simple compiler which generates bytecodes which are then instantly executed.
It includes simple 2D graphics abilities, but it is not capable of generating stand-alone executables. The name stands for "yet another BASIC".
Available for both Windows and various UNIX platforms. First released in May 1995. Version 2 was released in Summer 1996, with Windows support.
Included in the Demo CD included with the European Playstation 2, which has served to make it more popular. The source code is available, but consists of a library which links to an unsupplied application which contains the implementation details and the user interface, making it useless for learning how the console works, unfortunately.
There is also an emulator available which emulates the Playstation 2 version of yabasic, with the intention of allowing people to test their code before publishing it on the internet.
It is dual-licensed under both the Artistic License and the GNU General Public License, although these licenses do not apply to your own yabasic programs.