code: private boolean atomNeedsQuoting(final String s) {
          char c;
  
          if (s.length() == 0) {
              return true;
          }
          if (!isErlangLower(s.charAt(0))) {
              return true;
          }
  
          final int len = s.length();
          for (int i = 1; i < len; i++) {
              c = s.charAt(i);
  
              if (!isErlangLetter(c) && !isErlangDigit(c) && c != '@') {
                  return true;
              }
          }
          return false;
      }
docs: true if the atom should be displayed with quotation marks