November 2007 Archives

I just discovered the following blog article by Bill Clementson, from way back in 2003. Luckily, the links still worked, so I was able to get Info pages today for the Common Lisp HyperSpec courtesy of the GCL project.

Once installed, I found I could not easily lookup documentation for, say, mapcar, because it’s actually on the page for mapc. But SLIME’s hyperspec.el contained the indexing info I needed to write a new module which fires up the Info system on the correct section for the symbol you want defined.

This new module is called cl-info.el and is available from my Lisp repository. It rebinds the standard Emacs key for function help (C-h f) to lookup help in the HyperSpec instead, if you’re in a lisp-mode buffer.

NOTE: A fellow Lisper pointed me to this blog entry which offers a much nicer way to get the HyperSpec in Info form. It’s a little more work, but the quality of the result is superior and it has an index! Also, it makes my cl-info.el unnecessary, by relying entirely on the Info system itself.

This week’s script of the week is so simple, it doesn’t really deserve to be called a script. But since it’s highly useful and comes as a surprise to many people that it can be done so easily, here it is.

In my earlier article on running Hunchentoot behind Apache, I mentioned that it would not be very difficult to have Common Lisp persist your runtime state across a system reboot. Well, after a bit of work, I now have that support available. I’ve revised the article to reflect these changes, so please read there for more information!

After upgrading my system to Leopard this weekend, I decided to refresh Ready Lisp as well. It now contains both 32-bit and 64-bit builds of SBCL (which has been bumped to 1.0.11), so if you have a Core 2 Duo machine, you’ll be running Lisp at full 64-bit! Alas, Emacs itself cannot support 64-bit as a Carbon app, because there are no 64-bit Carbon libraries. SLIME has also been updated, to CVS latest as of today. Aquamacs is still the same version at 1.2a.

I did spend several hours trying to build a fully Universal package that would run on PowerPC as well (I have a PowerBook G4 in addition to this MacBook Pro), but it seems Leopard has broken the PowerPC port of SBCL. Some of the core OS structures have changed, such as os_context_t.

Ready Lisp is now being versioned according to the SBCL version it contains, which makes today’s release ReadyLisp-1.0.11-10.5-x86.dmg. The older version, which still works on 10.4, can be downloaded here.

NOTE: The recent loading bug for Leopard users has been fixed. Please re-download. Also, it still does not work on OS X 10.4 (Tiger) at the moment. I will have to create a separate build of SBCL for that version this weekend.

I wrote yesterday about setting up Hunchentoot, a Common Lisp web server running behind Apache, for rendering dynamic web pages in Lisp. What I neglected to mention was how one goes about coding such pages. Fortunately, that’s the easiest part of all, so I wanted to provide a very short primer on getting your first Lisp web pages up and running.

It’s hard for me to think of a more ideal platform for web design than Common Lisp. Imagine having a system that runs indefinitely, with the ability to “snapshot” its running state and restore exactly where you left off, and where updates can be applied live, at functional-level granularity, from anywhere. Oh, and let’s not forget the remote debugging and inspection capabilities! And I thought Visual Studio with ASP.NET was nice.

I haven’t written much this past week because I’ve been upgrading all the home’s machines to Leopard. So far it’s gone very smoothly, and I like the new OS!

The script for this week is about disk images. Since version 10.4 of the operating system, OS X has had the ability to internally (and transparently) compress disk images using bzip2. Probably because of compatibility issues with 10.3, I rarely ever see vendors compressing their disk images this way (I even see them using gzip on the image after it’s made, which makes no sense at all since internal gzip compression has been supported for a long time!). And so I wrote this script, which re-compresses disk image files using internal bzip2 compression. This can result in significant space savings over many images. And if it’s already been compressed with bzip2, the script reports this and changes nothing.