: r depth 0 ?do drop loop ;
: :D cr ." :D" cr ;
: q bye ;
: ls
  pad pad-minsize erase
  open-dir abort" cannot open directory"
  begin
  dup
  pad pad-minsize rot read-dir abort" cannot read directory"
  while
   pad swap cr type cr
  repeat
  drop close-dir abort" cannot close directory" 
;