Now you have a useful library of functions for dealing with pathnames. As I mentioned, these functions will come in handy in later chapters, particularly Chapters 23 and 27, where you’ll use walk-directory to crawl through directory trees containing spam messages and MP3 files. But before we get to that, though, I need to talk about object orientation, the topic of the next two chapters.

2Another special value, :wild-inferiors, can appear as part of the directory component of a wild pathname, but you won’t need it in this chapter.

4This is slightly broken in the sense that if **PROBE-FILE** signals an error for some other reason, this code will interpret it incorrectly. Unfortunately, the CLISP documentation doesn’t specify what errors might be signaled by **PROBE-FILE** and probe-directory, and experimentation seems to show that they signal simple-file-errors in most erroneous situations.