XLISP is a family of Lisp implementations written by and first released in 1983. The first version was a Lisp with object-oriented extensions for computers with limited power. The second version (XLISP 2.0) moved toward Common Lisp, but was by no means a complete implementation. After a long period of inactivity, the author released a new version based on , his Scheme implementation. The most current version follows the Scheme R3RS standard.