/////////////////////////////////////////////////////////////////////////////// | |
/// \file at.hpp | |
/// Proto callables Fusion at | |
// | |
// Copyright 2010 Eric Niebler. 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_PROTO_FUNCTIONAL_FUSION_AT_HPP_EAN_11_27_2010 | |
#define BOOST_PROTO_FUNCTIONAL_FUSION_AT_HPP_EAN_11_27_2010 | |
#include <boost/type_traits/add_const.hpp> | |
#include <boost/type_traits/remove_const.hpp> | |
#include <boost/type_traits/remove_reference.hpp> | |
#include <boost/fusion/include/at.hpp> | |
#include <boost/proto/proto_fwd.hpp> | |
namespace boost { namespace proto { namespace functional | |
{ | |
/// \brief A PolymorphicFunctionObject type that invokes the | |
/// \c fusion::at() accessor on its argument. | |
/// | |
/// A PolymorphicFunctionObject type that invokes the | |
/// \c fusion::at() accessor on its argument. | |
struct at | |
{ | |
BOOST_PROTO_CALLABLE() | |
template<typename Sig> | |
struct result; | |
template<typename This, typename Seq, typename N> | |
struct result<This(Seq, N)> | |
: fusion::result_of::at< | |
typename boost::remove_reference<Seq>::type | |
, typename boost::remove_const<typename boost::remove_reference<N>::type>::type | |
> | |
{}; | |
template<typename Seq, typename N> | |
typename fusion::result_of::at<Seq, N>::type | |
operator ()(Seq &seq, N const & BOOST_PROTO_DISABLE_IF_IS_CONST(Seq)) const | |
{ | |
return fusion::at<N>(seq); | |
} | |
template<typename Seq, typename N> | |
typename fusion::result_of::at<Seq const, N>::type | |
operator ()(Seq const &seq, N const &) const | |
{ | |
return fusion::at<N>(seq); | |
} | |
}; | |
}}} | |
#endif |