Home: a high-performance, free Common Lisp implementation

CMUCL is a free implementation of the Common Lisp programming language which runs on most major Unix platforms. It mainly conforms to the ANSI Common Lisp standard. Here is a summary of its main features:

Latest News

For the most up-to-date info and news, see CMUCL Gitlab Wiki. For older news see News. The old Trac wiki is still available but is deprecated in favor of the Gitlab wiki.

CMUCL 21e released
CMUCL 21e has been released, For information on the changes between 21e and 21d, we refer the reader to the 21e release notes.
CMUCL 21d released
CMUCL 21d has been released, For information on the changes between 21d and 21c, we refer the reader to the 21d release notes.
CMUCL 21c released
CMUCL 21c has been released, For information on the changes between 21c and 21b, we refer the reader to the 21c release notes.
CMUCL 21b released
CMUCL 21b has been released, For information on the changes between 21b and 21a, we refer the reader to the 21b release notes.
CMUCL 21a released
CMUCL 21a has been released, For information on the changes between 21a and 20f, we refer the reader to the 21a release notes. Because of the release, there will not be a 2014-10 snapshot.
CMUCL 20f released
CMUCL 20f has been released, For information on the changes between 20f and 20e, we refer the reader to the 20f release notes. Because of the release, there will not be a 2014-10 snapshot.
CMUCL moves to Gitlab from Trac
common-lisp.net announced that Gitlab would replace the current Trac system. The pages from Trac are slowing being migrated to CMUCL's gitlab page.
CMUCL 20e released
CMUCL 20e has been released, For information on the changes between 20e and 20d, we refer the reader to the 20e release notes. Because of the release, there will not be a 2013-10 snapshot.

What is Common Lisp?

Common Lisp is well suited to large programming projects and explorative programming. The language has a dynamic semantics which distinguishes it from languages such as C and Ada. It features automatic memory management, an interactive incremental development environment, a module system, a large number of powerful data structures, a large standard library of useful functions, a sophisticated object system supporting multiple inheritance and generic functions, an exception system, user-defined types and a macro system which allows programmers to extend the language.

Pascal is for building pyramids -- imposing, breathtaking structures built by armies pushing heavy blocks into place. Lisp is for building organisms ...
Alan Perlis