function quit(code, token, a, b) {
    var percentage = Math.floor((token.line / state.lines.length) * 100);
    var message = messages.errors[code].desc;

    var exception = {
      name: "JSHintError",
      line: token.line,
      character: token.from,
      message: message + " (" + percentage + "% scanned).",
      raw: message,
      code: code,
      a: a,
      b: b
    };

    exception.reason = supplant(message, exception) + " (" + percentage +
      "% scanned).";

    throw exception;
  }
TODO: Extend this restriction to *all* ES6-specific options.