sS shortenInTheMiddle(int max, CharSequence s) {
  if (s == null) ret "";
  if (max < 0) ret str(s);
  if (s.length() <= max) ret str(s);
  S shortener = "...";
  int m = max-shortener.length();
  ret subCharSequence(s, 0, m-m/2)
    + shortener
    + subCharSequence(s, s.length()-m/2);
}