Wikipedia
CLISP
In computing, CLISP is an implementation of the programming language Common Lisp originally developed by Bruno Haible and Michael Stoll for the Atari ST. Today it supports operating systems Unix and Microsoft Windows.
CLISP includes an interpreter, a bytecode compiler, debugger, socket interface, high-level foreign language interface, strong internationalization support, and two object systems: Common Lisp Object System (CLOS) and metaobject protocol (MOP).
It is written in C and Common Lisp. It is now part of the GNU Project and is free software, available under the terms of the GNU General Public License (GPL).