diff options
Diffstat (limited to 'boost/hana/map.hpp')
| -rw-r--r-- | boost/hana/map.hpp | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/boost/hana/map.hpp b/boost/hana/map.hpp index cccf6cf3b9..8da5012190 100644 --- a/boost/hana/map.hpp +++ b/boost/hana/map.hpp @@ -40,9 +40,12 @@ Distributed under the Boost Software License, Version 1.0. #include <boost/hana/functional/partial.hpp> #include <boost/hana/fwd/any_of.hpp> #include <boost/hana/fwd/at_key.hpp> +#include <boost/hana/fwd/difference.hpp> #include <boost/hana/fwd/erase_key.hpp> +#include <boost/hana/fwd/intersection.hpp> #include <boost/hana/fwd/is_subset.hpp> #include <boost/hana/fwd/keys.hpp> +#include <boost/hana/fwd/union.hpp> #include <boost/hana/insert.hpp> #include <boost/hana/integral_constant.hpp> #include <boost/hana/keys.hpp> @@ -53,6 +56,7 @@ Distributed under the Boost Software License, Version 1.0. #include <boost/hana/unpack.hpp> #include <boost/hana/value.hpp> + #include <cstddef> #include <type_traits> #include <utility> @@ -480,6 +484,71 @@ BOOST_HANA_NAMESPACE_BEGIN }; ////////////////////////////////////////////////////////////////////////// + // union_ + ////////////////////////////////////////////////////////////////////////// + template <> + struct union_impl<map_tag> { + template <typename Xs, typename Ys> + static constexpr auto apply(Xs&& xs, Ys&& ys) { + return hana::fold_left(static_cast<Xs&&>(xs), static_cast<Ys&&>(ys), + hana::insert); + } + }; + + ////////////////////////////////////////////////////////////////////////// + // intersection_ + ////////////////////////////////////////////////////////////////////////// + namespace detail { + template <typename Ys> + struct map_insert_if_contains { + Ys const& ys; + + // Second template param will be pair + // Get its key and check if it exists, if it does, insert key, value pair. + template <typename Result, typename Pair> + static constexpr auto helper(Result&& result, Pair&& pair, hana::true_) { + return hana::insert(static_cast<Result&&>(result), static_cast<Pair&&>(pair)); + } + + template <typename Result, typename Pair> + static constexpr auto helper(Result&& result, Pair&&, hana::false_) { + return static_cast<Result&&>(result); + } + + template <typename Result, typename Pair> + constexpr auto operator()(Result&& result, Pair&& pair) const { + constexpr bool keep = hana::value<decltype(hana::contains(ys, hana::first(pair)))>(); + return map_insert_if_contains::helper(static_cast<Result&&>(result), + static_cast<Pair&&>(pair), + hana::bool_c<keep>); + } + }; + } + + template <> + struct intersection_impl<map_tag> { + template <typename Xs, typename Ys> + static constexpr auto apply(Xs&& xs, Ys const& ys) { + return hana::fold_left(static_cast<Xs&&>(xs), hana::make_map(), + detail::map_insert_if_contains<Ys>{ys}); + } + }; + + ////////////////////////////////////////////////////////////////////////// + // difference + ////////////////////////////////////////////////////////////////////////// + template <> + struct difference_impl<map_tag> { + template <typename Xs, typename Ys> + static constexpr auto apply(Xs&& xs, Ys&& ys) { + return hana::fold_left( + hana::keys(static_cast<Ys&&>(ys)), + static_cast<Xs&&>(xs), + hana::erase_key); + } + }; + + ////////////////////////////////////////////////////////////////////////// // Foldable ////////////////////////////////////////////////////////////////////////// template <> |