anchor.diff:  
   (defun send-file (file-path route-path local-path request response)
     (declare (ignore request route-path))
  -  (let ((path (concatenate 'string local-path file-path))
  +  (let ((path (concatenate 'string local-path "/" file-path))
           (buffer (make-array 1024 :element-type '(unsigned-byte 8)))
           (stream (start-response response :headers '(:content-type "text/plain"))))
       (with-open-file (fstream path :element-type '(unsigned-byte 8))
  
positive.code: (defun directory-listing (file-path route-path local-path request response)
    "Send a directory listing."
    (declare (ignore request))
    (let ((files (directory (concatenate 'string local-path file-path "/*.*")))
          (stream (start-response response :headers '(:content-type "text/html"))))
      (flet ((write-line (string)
               (write-sequence (babel:string-to-octets (concatenate 'string string #(#\return #\newline))
  
negative.code:            (resource (concatenate 'string route-path "/(.*)$")))
        (clear-route :get resource)
        (defroute (:get resource) (req res args)
          (let* ((file-path (remove-trailing-slashes (car args)))
                 (local-file (concatenate 'string
                                          (namestring local-path)
                                          "/" file-path)))
            (cond
              ((cl-fad:directory-exists-p local-file)
               (directory-listing file-path route-path local-path req res))
              ((cl-fad:file-exists-p local-file)
               (send-file file-path route-path local-path req res))
              (t 
               (next-route))))))))
  