add boost on mac

macx64/include/boost/hof/is_invocable.hpp

@@ -0,0 +1,72 @@
+/*=============================================================================
+    Copyright (c) 2014 Paul Fultz II
+    is_invocable.h
+    Distributed under the Boost Software License, Version 1.0. (See accompanying
+    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+==============================================================================*/
+
+#ifndef BOOST_HOF_GUARD_IS_CALLABLE_H
+#define BOOST_HOF_GUARD_IS_CALLABLE_H
+
+/// is_invocable
+/// ===========
+/// 
+/// Description
+/// -----------
+/// 
+/// The `is_invocable` metafunction checks if the function is callable with
+/// certain parameters.
+/// 
+/// Requirements
+/// ------------
+/// 
+/// F must be:
+/// 
+/// * [Invocable](Invocable)
+/// 
+/// Synopsis
+/// --------
+/// 
+///     template<class F, class... Ts>
+///     struct is_invocable;
+/// 
+/// Example
+/// -------
+/// 
+///     #include <boost/hof.hpp>
+///     using namespace boost::hof;
+/// 
+///     struct is_invocable_class
+///     {
+///         void operator()(int) const
+///         {
+///         }
+///     };
+///     static_assert(is_invocable<is_invocable_class, int>(), "Not callable");
+/// 
+///     int main() {}
+/// 
+
+
+#include <boost/hof/detail/can_be_called.hpp>
+#include <boost/hof/apply.hpp>
+
+namespace boost { namespace hof {
+
+template<class F, class... Ts>
+struct is_invocable 
+: detail::can_be_called<detail::apply_f, F, Ts...>
+{};
+
+template<class F, class... Ts, class... Us>
+struct is_invocable<F(Ts...), Us...>
+{
+    static_assert(!std::is_same<F, F>::value, 
+        "The is_invocable<F(Args...)> form is not supported because it is problematic."
+        "Please use is_invocable<F, Args...> instead."
+    );
+};
+
+}} // namespace boost::hof
+
+#endif