I enjoy using the range library, and also foreach. When dealing with legacy code, the MFC / ATL range adaptors are wonderful. Unfortunately, the CMap and CMapStringToString iterators return CPair objects rather than std::pair, hence causing the select_first / select_second_mutable / select_second_const metafunctions to fail. I added these specializations to allow them to work with the map_keys and map_values adaptors. Hopefully they will be of use to someone in the future or adapted to be included with the other MFC / ATL code. Would it be worthwhile to format this as a patch to the library? namespace boost { namespace range_detail { // CMap and CMapStringToString range iterators return CPair, // which has a key and value member. Other MFC range iterators // already return adapted std::pair objects. This allows usage // of the map_keys and map_values range adaptors with CMap // and CMapStringToString // specialization for CMap template<class KEY, class ARG_KEY, class VALUE, class ARG_VALUE> struct select_first<CMap<KEY, ARG_KEY, VALUE, ARG_VALUE>> { typedef BOOST_DEDUCED_TYPENAME CMap<KEY, ARG_KEY, VALUE, ARG_VALUE> map_type; typedef BOOST_DEDUCED_TYPENAME range_reference<const map_type>::type argument_type; typedef BOOST_DEDUCED_TYPENAME const KEY& result_type; result_type operator()( argument_type r ) const { return r.key; } }; template<class KEY, class ARG_KEY, class VALUE, class ARG_VALUE> struct select_second_mutable<CMap<KEY, ARG_KEY, VALUE, ARG_VALUE>> { typedef BOOST_DEDUCED_TYPENAME CMap<KEY, ARG_KEY, VALUE, ARG_VALUE> map_type; typedef BOOST_DEDUCED_TYPENAME range_reference<map_type>::type argument_type; typedef BOOST_DEDUCED_TYPENAME VALUE& result_type; result_type operator()( argument_type r ) const { return r.value; } }; template<class KEY, class ARG_KEY, class VALUE, class ARG_VALUE> struct select_second_const<CMap<KEY, ARG_KEY, VALUE, ARG_VALUE>> { typedef BOOST_DEDUCED_TYPENAME CMap<KEY, ARG_KEY, VALUE, ARG_VALUE> map_type; typedef BOOST_DEDUCED_TYPENAME range_reference<const map_type>::type argument_type; typedef BOOST_DEDUCED_TYPENAME const VALUE& result_type; result_type operator()( argument_type r ) const { return r.value; } }; // specialization for CMapStringToString template<> struct select_first<CMapStringToString> { typedef range_reference<const CMapStringToString>::type argument_type; typedef const CString& result_type; result_type operator()( argument_type r ) const { return r.key; } }; template<> struct select_second_mutable<CMapStringToString> { typedef range_reference<CMapStringToString>::type argument_type; typedef CString& result_type; result_type operator()( argument_type r ) const { return r.value; } }; template<> struct select_second_const<CMapStringToString> { typedef range_reference<const CMapStringToString>::type argument_type; typedef const CString& result_type; result_type operator()( argument_type r ) const { return r.value; } }; } } -- - Adam D. Walling