static S readerToString(Reader r) ctex {
  if (r == null) null;
  try {
    new StringBuilder buf;
    int n = 0;
    while (true) {
      int ch = r.read();
      if (ch < 0)
        break;
      buf.append((char) ch);
      ++n;
      //if ((n % loadPage_verboseness) == 0) print("  " + n + " chars read");
    }
    ret buf.toString();
  } finally {
    r.close();
  }  
}