let lexbuf = Lexing.from_channel stdin in
try
  let html  = Parser.html Lexer.token lexbuf in  (* parse input *)
  let ()    = Weeding.weed_html html in          (* check nested anchors  *)
  let html' = Transform.transform_html html in   (* eliminate nested b tags *)
  let ()    = Outline.outline_html html' in      (* print an outline *)
  ()
with
  | Failure msg         -> print_endline ("Failure --- " ^ msg)
  | Parsing.Parse_error -> print_endline ("Parse error")
  | End_of_file         -> print_endline "Parse error: unexpected end of string"