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// Copyright (c) 2013 Kyle Lutz <>
// Distributed under the Boost Software License, Version 1.0
// See accompanying file LICENSE_1_0.txt or copy at
// See for more information.


#include <cstddef>

#include <boost/compute/types/fundamental.hpp>
#include <boost/compute/type_traits/scalar_type.hpp>

namespace boost {
namespace compute {
namespace detail {

// meta-function returning the result type for get<N>()
template<size_t N, class Arg>
struct get_result_type
    typedef typename scalar_type<Arg>::type type;

template<size_t N, class Arg, class T>
struct invoked_get
    typedef typename get_result_type<N, T>::type result_type;

    invoked_get(const Arg &arg)
        : m_arg(arg)

    Arg m_arg;

} // end detail namespace

/// Returns the \c N'th element of an aggregate type (e.g. scalarN,
/// pair, tuple, etc.).
/// \see \ref field "field<T>"
template<size_t N>
struct get
    /// \internal_
    template<class> struct result;

    /// \internal_
    template<class F, class Arg>
    struct result<F(Arg)>
        typedef typename detail::get_result_type<N, Arg>::type type;

    template<class Arg>
        N, Arg, typename boost::remove_cv<typename Arg::result_type>::type
    > operator()(const Arg &arg) const
        typedef typename boost::remove_cv<typename Arg::result_type>::type T;

        return detail::invoked_get<N, Arg, T>(arg);

} // end compute namespace
} // end boost namespace