val create : unit ‑> tval parse : t ‑> Lexing.lexbuf ‑> parsed_valueConsume exactly one s-expression from the given lexing buffer
val parse_opt : t ‑> Lexing.lexbuf ‑> parsed_value optionConsume exactly one s-expression from the given lexing buffer. Returns None if
the end of input is reached before seeing any s-expression.