CLISP

CLISP is a free implementation of the Common Lisp language, first written by Bruno Haible and Michael Stoll for the Atari ST home computer and later extended to run on Unix systems and Microsoft Windows. It bundles an interpreter, a bytecode compiler, a debugger, a socket interface, a high-level foreign language interface and strong support for internationalization, together with two object systems, the Common Lisp Object System and a metaobject protocol. The system is written in C and Common Lisp and is now part of the GNU Project, distributed as free software under the GNU General Public License. Haible first did not plan to release it under that licence, and agreed to do so after a well-publicised exchange with Richard Stallman over whether CLISP was a derivative work of the GNU readline library. Because it runs on a bytecode virtual machine it is very portable and simple to set up, and Paul Graham used it to run the software of his Viaweb startup, which became Yahoo Stores.