nsReadingIterator<CharT> iter( EndReading() );
nsReadingIterator<CharT> iter; EndReading(iter);
basic_nsAReadableString<CharT>::Last() const  {    NS_ASSERTION(Length()>0, "|Last()| on an empty string");    // nsReadingIterator<CharT> iter; EndReading(iter);    nsReadingIterator<CharT> iter( EndReading() );    if ( !IsEmpty() )      iter -= 1;    return *iter; // Note: this has undefined results if |IsEmpty()|  }