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:
- 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
- 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
- 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
- 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
- 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
For the most up-to-date info and news, see
CMUCL Trac. For older
news see News.
- 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 ...