exception Syntax_error of ((int * int) option * string)
let get_lexing_position lexbuf =
let p = Lexing.lexeme_start_p lexbuf in
let line_number = p.Lexing.pos_lnum in
let column = p.Lexing.pos_cnum - p.Lexing.pos_bol + 1 in
(line_number, column)
let default default_value opt =
match opt with
| None -> default_value
| Some value -> value