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:

• Support for static arrays that are never moved by GC but are properly removed when no longer referenced.
• Unicode support, including many of the most common external formats such as UTF-8 and support for handling Unix, DOS, and Mac end-of-line schemes.
• native double-double floats including complex double-double floats and specialized arrays for double-double floats and and complex double-double floats that give approximately 106 bits (32 digits) of precision.
• a sophisticated native-code compiler which is capable of powerful type inferences, and generates code competitive in speed with C compilers.
• generational garbage collection and multiprocessing capability on the x86 ports.
• a foreign function interface which allows interfacing with C code and system libraries, including shared libraries on most platforms, and direct access to Unix system calls.
• support for interprocess communication and remote procedure calls.
• an implementation of CLOS, the Common Lisp Object System, which includes multimethods and a metaobject protocol.
• a graphical source-level debugger using a Motif interface, and a code profiler.
• an interface to the X11 Window System (CLX), and a sophisticated graphical widget library (Garnet).
• programmer-extensible input and output streams.
• an Emacs-like editor implemented in Common Lisp.
• freely redistributable: free, with full source code (most of which is in the public domain) and no strings attached (and no warranty). Like the GNU/Linux and *BSD operating systems, CMUCL is maintained and improved by a team of volunteers collaborating over the Internet.

Latest News

Snapshot 2013-04

The 2013-04 snapshot has been released. See the release notes for details, but here is a quick summary of the changes between the this snapshot and the previous snapshot.

• Fix startup crashes on some Debian Linux versions. This was caused by the release string not having a patch version.
• FILE-POSITION no longer returns incorrect values. See ticket #79.
• Fix error in (format t "~ve" 21 5d-324). (See ticket #80).

Snapshot 2013-03-a

Due to a serious error (see ticket #76) introduced in 2013-02 and persisting in 2013-03, a new snapshot, 2013-03-a, has been released. See the release notes for details, but here is a quick summary of the changes between the this snapshot and the previous snapshot.

• ASDF updated to version 2.32.
• Update to support Unicode 6.2
• Ticket #76 fixed.

Snapshot 2013-03

The 2013-03 snapshot has been released. See the release notes for details, but here is a quick summary of the changes between the this snapshot and the previous snapshot.

• ASDF updated to version 2.30.
• Attempts to modify the standard readtable or standard pprint dispatch table will signal an error.
• An error in FILE-POSITION has been fixed (Ticket #74).

Snapshot 2013-02

The 2013-02 snapshot has been released. See the release notes for details, but here is a quick summary of the changes between the this snapshot and the previous snapshot.

• ASDF updated to version 2.28.
• Ticket #65 fixed.
• Ticket #69 fixed.
• Ticket #70 fixed.
• Ticket #71 fixed.
• Ticket #72 fixed.

Snapshot 2013-01

The 2013-01 snapshot has been released. See the release notes for details, but here is a quick summary of the changes between the this snapshot and

• DEFINE-COMPILER-MACRO has source-location information for the definition.
• :ALIEN-CALLBACK added to *FEATURES* for platforms that support alien callbacks. This is currently available for all supported platforms.
• REPLACE can now handle strings of any supported size.
• Ticket #66 fixed.
• Ticket #67 fixed.
• Ticket #68 fixed:

Snapshot 2012-12

The 2012-12 snapshot has been released, See the release notes for details, but here is a quick summary of the changes between the this snapshot and the previous snapshot:

• ASDF2 updated to 2.26
• Unicode completion has been reverted to the older version due to the inability to complete #\hangul_syllable_. Trac ticket:52 reopened.
• Starting with this snapshot, only the unicode version of CMUCL is officially supported. The 8-bit version and code will not be deleted, but binaries will no longer be supplied for the 8-bit (non-unicode) version.

CMUCL 20d released

CMUCL 20d has been released, For information on the changes between 20d and 20c, we refer the reader to the 20d release notes. Because of the release, there will not be a 2011-11 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