static S readerToString(Reader r) {
  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();
}