add boost on mac

macx64/include/boost/hana/detail/operators/monad.hpp

@@ -0,0 +1,35 @@
+/*!
+@file
+Defines operators for Monads.
+
+@copyright Louis Dionne 2013-2017
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#ifndef BOOST_HANA_DETAIL_OPERATORS_MONAD_HPP
+#define BOOST_HANA_DETAIL_OPERATORS_MONAD_HPP
+
+#include <boost/hana/config.hpp>
+#include <boost/hana/core/tag_of.hpp>
+#include <boost/hana/fwd/chain.hpp>
+
+#include <type_traits>
+
+
+BOOST_HANA_NAMESPACE_BEGIN namespace detail {
+    template <typename Tag>
+    struct monad_operators {
+        static constexpr bool value = false;
+    };
+
+    namespace operators {
+        template <typename Xs, typename F, typename = typename std::enable_if<
+            detail::monad_operators<typename hana::tag_of<Xs>::type>::value
+        >::type>
+        constexpr auto operator|(Xs&& xs, F&& f)
+        { return hana::chain(static_cast<Xs&&>(xs), static_cast<F&&>(f)); }
+    } // end namespace operators
+} BOOST_HANA_NAMESPACE_END
+
+#endif // !BOOST_HANA_DETAIL_OPERATORS_MONAD_HPP