Clozure CL 1.7 prerelease available for testing

A prerelease version of Clozure CL 1.7 is now available for testing.

Clozure CL is a free Common Lisp implementation that runs on a number of architectures and operating systems.

Please see the draft release notes for more information, including instructions on how to use Subversion to download a copy.

We would appreciate any bug reports or comments about the prerelease version. The best way to do that is via After you register, click on the “New Ticket” link in the navigation bar near the top of the page. The registration requirement is regrettable, but we get overwhelmed by spammers without it.

After a period of testing and bug fixing, we will build updated binaries and make the 1.7 release official.

Please remember that this is a prerelease. We hope you will test your software with it and report any problems you find. But please don’t use it to build software that you will distribute to unsuspecting users.

Thank you for helping to make Clozure CL better.

Clozure CL 1.6 release candidate

Release candidate binaries of Clozure CL 1.6 are now available.

Clozure CL is a free Common Lisp implementation that runs on a number of architectures and operating systems. In addition to the x86[-64] and PowerPC ports, a Linux/ARM port has been added.

Please see the draft release notes for more information, including instructions on how to use Subversion to get a copy if you would like to test it out.

We would appreciate any bug reports or comments about the release candidate. After a couple of weeks of testing (and bug fixing), we’ll build updated binaries and make the release official.

Win an Efika MX Smartbook at ILC

If you attend this year’s International Lisp Conference, be sure to stop by Clozure’s booth to register for a chance to win an Efika MX Smartbook.

(The ARM Linux port of Clozure CL needs beta testers, and we figure that raffling off a nice little machine that CCL runs on is a way to get … well,  at least one more tester.)

Thanks to Genesi USA for donating the machine that someone will win.

Preliminary Windows GUI support via Cocotron

CCL on 32-bit Windows platforms now includes experimental support for the Cocoa frameworks using the Cocotron open source project.  For details on Cocotron, see

This support is only available in the trunk.

CCL provides a pre-built set of DLLs for Cocotron’s Foundation and AppKit frameworks but, as this support is still experimental, you must explicitly checkout these files into your CCL installation.  To do so, execute the command line
svn checkout
in the directory where you have installed CCL (i.e., in the directory containing wx86cl.exe).

Once you have checked out the DLLs (and supporting files), you load Cocotron just as you do Cocoa on the Mac.  In other words, evaluate the form
  (require  "COCOA")
in CCL which will load the Cocotron’s Foundation and AppKit frameworks and start the CCL IDE.  You can also evaluate the form
to build a standalone copy of the CCL IDE.

You can also build standalone Cocoa applications on Windows using build-application as you do today on Mac OS X.

As noted before, this support is experimental.

While the IDE runs, it is not yet stable enough to use for actual development on Windows.  Use it at your own risk.

Cocotron is a work in progress.  It does not yet implement the entire set of APIs defined by Apple.  It also has bugs. If you run into problems, you may want to try to create a simple Objective-C program to see if you can reproduce the problem without CCL.  If the problem is reproducible, please report the problem to the Cocotron developers at