17 #ifdef __cpp_lib_ranges
20 #include <boost/range/adaptor/filtered.hpp>
21 #include <boost/range/adaptor/map.hpp>
22 #include <boost/range/adaptor/reversed.hpp>
23 #include <boost/range/adaptor/transformed.hpp>
28 #ifdef __cpp_lib_ranges
38 constexpr
auto filter = boost::adaptors::filtered;
39 constexpr
auto keys = boost::adaptors::map_keys;
40 constexpr
auto reverse = boost::adaptors::reversed;
41 constexpr
auto transform = boost::adaptors::transformed;
42 constexpr
auto values = boost::adaptors::map_values;