CMU Common Lisp

CMU Common Lisp, usually called CMUCL, is a free implementation of the Common Lisp language that was originally developed at Carnegie Mellon University. Its earliest ancestor predates Common Lisp and was part of the Spice Lisp project around 1980; in 1985 Rob MacLachlan began rewriting the compiler into what became the native code compiler named Python, unrelated to the Python language. After Carnegie Mellon cancelled the project, volunteers took over maintenance and by 1996 were making regular releases from their own infrastructure, and a port to the Intel x86 architecture followed using a conservative garbage collector. CMUCL includes an interpreter used mainly for the read-eval-print loop, a compact bytecode machine, generational garbage collection, a foreign function interface to C, an implementation of the Common Lisp Object System with multimethods and a metaobject protocol, the Hemlock editor and the Garnet widget library. It runs on most Unix-like systems, and Steel Bank Common Lisp is derived from it.