struct
  type string_to_raw_item = [
  | `empty_line of Pos.t
  | `incomplete_input of Pos.t * string list * string option
  | `malformed_partial_sequence of string
  ]
  with sexp

  type t = [
    string_to_raw_item
  | `unnamed_char_seq of char_seq
  | `unnamed_int_seq of int_seq
  ]
  with sexp
end