(form "20300" (size 45 6)
  (heading "BLOCK MODEL REPORT")
  (label (position 5 3) (text "Report filename"))
  (field "report_name" (position 20 3) (display_length 20) (input allowed)
    (translate lower) (null disallowed) (max_length 40)
    (file output (extension trim "*.not"))
  )
  (default_buttons)
)