Function regex_to_lark 

pub fn regex_to_lark(rx: &str, use_ascii: &str) -> String

Make sure given regex can be used inside /…/ in Lark syntax. Also if use_ascii.contains('d') replace \d with [0-9] and \D with [^0-9]. Similarly for \w/\W ([0-9a-zA-Z_]) and \s/\S ([ \t\n\r\f\v]). For standard Unicode Python3 or Rust regex crate semantics use_ascii = "" For JavaScript or JSON Schema semantics use_ascii = "dw" For Python2 or byte patters in Python3 semantics use_ascii = "dws" More flags may be added in future.