support/utility/is_callable.hpp

0001 /*//////////////////////////////////////////////////////////////////////////////
0002     Copyright (c) 2014 Jamboree
0003
0004     Distributed under the Boost Software License, Version 1.0. (See accompanying
0005     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 //////////////////////////////////////////////////////////////////////////////*/
0007 #ifndef BOOST_SPIRIT_X3_IS_CALLABLE_HPP_INCLUDED
0008 #define BOOST_SPIRIT_X3_IS_CALLABLE_HPP_INCLUDED
0009
0010 #include <boost/mpl/bool.hpp>
0011
0012 namespace boost { namespace spirit { namespace x3 { namespace detail
0013 {
0014     template <typename Sig, typename Enable = void>
0015     struct is_callable_impl : mpl::false_ {};
0016
0017     template <typename F, typename... A>
0018     struct is_callable_impl<F(A...),
0019         decltype(void(std::declval<F>()(std::declval<A>()...)))>
0020       : mpl::true_
0021     {};
0022 }}}}
0023
0024 namespace boost { namespace spirit { namespace x3
0025 {
0026     template <typename Sig>
0027     struct is_callable;
0028
0029     template <typename F, typename... A>
0030     struct is_callable<F(A...)> : detail::is_callable_impl<F(A...)> {};
0031 }}}
0032
0033
0034 #endif