static CloseableCharSequence iso8859_readOnlyFileAsCharSequence(File f, O... _) {
  optPar bool noToString; // if set, only subsequences can be converted to a string
  
  int l = toInt_safe(l(f));
  RandomAccessFile raf = randomAccessFileForReading(f);
  ret new CloseableCharSequence {
    public int length() { ret l; }
    public char charAt(int i) ctex { raf.seek(i); ret (char) raf.readByte(); }
    public CharSequence subSequence(int from, int to) { ret substringObject(this, from, to); }
    toString {
      if (noToString) fail("Too big for converting to string");
      ret charSequenceToStringByChar(this);
    }
    public void close { _close(raf); }
  };
}