namespace boost {
  namespace text {
    template<nf Normalization, typename Char, typename String> 
      struct basic_rope_view;
    template<nf Normalization, typename Char, typename String> 
      text_sort_key 
      collation_sort_key(basic_rope_view< Normalization, Char, String > const &, 
                         collation_table const &, 
                         collation_flags = collation_flags::none);
    template<nf Normalization1, typename Char1, typename String1, 
             nf Normalization2, typename Char2, typename String2> 
      int collate(basic_rope_view< Normalization1, Char1, String1 > const &, 
                  basic_rope_view< Normalization2, Char2, String2 > const &, 
                  collation_table const &, 
                  collation_flags = collation_flags::none);
  }
}namespace std {
  namespace ranges {
  }
}