type 'a start =
  | Module : (Script.var option * Script.definition) start
  | Script : Script.script start
  | Script1 : Script.script start

exception Syntax = Script.Syntax

let parse' name lexbuf start =
  lexbuf.Lexing.lex_curr_p <-
    {lexbuf.Lexing.lex_curr_p with Lexing.pos_fname = name};
  try start Lexer.token lexbuf
  with Syntax (region, s) ->
    let region' = if region <> Source.no_region then region else
      {Source.left = Lexer.convert_pos lexbuf.Lexing.lex_start_p;
       Source.right = Lexer.convert_pos lexbuf.Lexing.lex_curr_p} in
    raise (Syntax (region', s))

let parse (type a) name lexbuf : a start -> a = function
  | Module -> parse' name lexbuf Parser.module1
  | Script -> parse' name lexbuf Parser.script
  | Script1 -> parse' name lexbuf Parser.script1

let string_to start s =
  let lexbuf = Lexing.from_string s in
  parse "string" lexbuf start

let string_to_script s = string_to Script s
let string_to_module s = snd (string_to Module s)