+
+
+(defun directory-tree (filename)
+ "Returns a tree of pathnames for sub-directories of a directory"
+ (let* ((root (canonicalize-directory-name filename))
+ (subdirs (loop for path in (directory
+ (make-pathname :name :wild
+ :type :wild
+ :defaults root))
+ when (probe-directory path)
+ collect (canonicalize-directory-name path))))
+ (when (find nil subdirs)
+ (error "~A" subdirs))
+ (when (null root)
+ (error "~A" root))
+ (if subdirs
+ (cons root (mapcar #'directory-tree subdirs))
+ (if (probe-directory root)
+ (list root)
+ (error "root not directory ~A" root)))))
+
+