SBCL: A Sanely-Bootstrappable Common Lisp

This paper describes the development of an implementation of Common Lisp with the peculiarity that it is bootstrappable neither solely from itself, nor from some other language, but rather from a variety of other Common Lisp implementations. We explain the motivation for this bootstrap strategy, discuss some of the technical details involved in achieving it, and attempt to assess the technical and social effects that it has had on the development of the implementation and on its user and developer community.