The guided-tour has a test application that's a file-browser. I wanted to try to figure out how to read pathnames in an application I'm writing, so I tried to fire up the file-browser. Unfortunately, it didn't work, mostly because it made assumptions about the way that CL pathnames work that didn't map onto either SBCL or ACL, the two applications on which I tried it.
I am attaching a patch which makes it work (if the patch about pathname presentations, that I sent earlier today, is also present). I am inclined to commit this, since (a) it's just part of an article, so can't be on anyone's critical path and (b) it seems like a Bad Thing to have a tutorial out there featuring exemplars that don't work. The downside is that CL pathnames are so intractable that the only good way I found to make this work was to use CL-FAD. Dependencies on libraries seems generally like a bad thing in a small tutorial like this, but importing enough code to make it work w/o the library would probably obscure the tutorial intent even worse.
BTW, I think a more elegant solution might be made that would use satisfies to define the dir-pathname presentation-type more declaratively. But I couldn't figure out how to do it...
best, Robert