anchor.diff:                  (fnames (map (lambda (d) (@ d :string)) (@ filtered :files)))
                   (dirnames (map (lambda (d) (@ d :string)) (@ filtered :directories)))
                   (key-code (@ event key-code)))
  -           (console.log "KEY CODE" key-code)
              (cond
                ((= 9 key-code)
                 (chain event (prevent-default))
                 (chain elem (focus))
  -              (console.log "FOUND TAB KEYPRESS" "TODO"))
  +              (setf (@ elem value) (common-prefix-of val (chain fnames (concat dirnames)))))
                ((and (= 13 key-code) (member? val fnames))
                 (setf (@ window location href) (+ "/#book=" val)))
                ((and (= 13 key-code) (member? dval dirnames))
                 (filesystem! (by-selector ".filesystem-view") dval))
                ((or (= 8 key-code) (= 46 key-code))
  -              (console.log "FOUND DELETING NON-CHAR KEYPRESS" key-code "RE-RUNNING ls REQUEST")
                 (filesystem!
                  (by-selector ".filesystem-view")
                  (+ (chain val (split "/") (slice 0 -1) (join "/")) "/")
  
positive.code: (define-handler (js/notebook-selector.js :content-type "application/javascript") ()
    (ps
      (defvar *current-fs-listing* nil)
  
      (defun notebook-link-template (notebook current-notebook-id)
        (if (equal? current-notebook-id (@ notebook :path))
  
negative.code:                 (cond
                    ((and (= (length (@ filtered :directories)) 1)
                          (= (length (@ filtered :files)) 0))
                     (setf (@ elem value) (@ filtered :directories 0 :string))
                     (filesystem! (by-selector ".filesystem-view") (@ filtered :directories 0 :string)))
                    ((and (= (length (@ filtered :directories)) 0)
  