factor method

double factor()

Implementation

double factor() {
  if (match('(')) {
    double x = parse();
    match(')');
    return x;
  }

  int start = i;
  while (i < s.length && "0123456789.".contains(s[i])) {
    i++;
  }
  return double.parse(s.substring(start, i));
}