CLISP

CLISP is a free implementation of the Common Lisp programming language. It was developed by Bruno Haible and Michael Stoll and is part of the GNU Project. CLISP is available as a package with interpreter, bytecode compiler, debugger and socket interface.

Not originally intended Bruno Haible to publish CLISP under the GPL. However, after an email exchange with Richard Stallman he agreed. Stallman had complained that CLISP violate the GPL by using the GNU readline library.

CLISP is highly portable and runs on nearly all flavors of Unix, including Linux, all BSD successors as well as Windows.