Please note that OpenLisp is not only an interpreter. It has also a lisp->C compiler that allows to write standalone executables. Speed is then timed with an average of x20 improvement.

The source code is fully available to paid customers. They are allowed to embed a Lisp engine in their own applications.

OpenLisp is free to use for non-commercial application.

Open means Open to the world, not Open Source.

See more on Wikipedia.

How fast is the interpreter? Make your own benchs and see...

Last but not least, it is extreeeeemnly portable.

C.