namespace boost {
  namespace genetics {
    template<typename StringType, typename IndexArrayType, 
             typename AddrArrayType, bool Writable> 
      class basic_two_stage_index;

    typedef basic_two_stage_index< mapped_augmented_string, mapped_vector< uint32_t >, mapped_vector< uint32_t >, false > mapped_two_stage_index;
    typedef basic_two_stage_index< augmented_string, std::vector< uint32_t >, std::vector< uint32_t >, true > two_stage_index;
    template<typename charT, typename traits, typename StringType, 
             typename IndexArrayType, typename AddrArrayType, bool Writable> 
      std::basic_ostream< charT, traits > & 
      operator<<(std::basic_ostream< charT, traits > & os, 
                 const basic_two_stage_index< StringType, IndexArrayType, AddrArrayType, Writable > & x);
  }
}