front.hpp

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#ifndef BOOST_MPL_VECTOR_AUX_FRONT_HPP_INCLUDED
#define BOOST_MPL_VECTOR_AUX_FRONT_HPP_INCLUDED
 
// Copyright Aleksey Gurtovoy 2000-2008
//
// 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)
//
// See http://www.boost.org/libs/mpl for documentation.
 
// $Id: front.hpp 13472 2017-08-22 07:53:44Z richean $
// $Date: 2017-08-22 09:53:44 +0200 (Di, 22 Aug 2017) $
// $Revision: 13472 $
 
#include <boost/mpl/front_fwd.hpp>
#include <boost/mpl/vector/aux_/at.hpp>
#include <boost/mpl/vector/aux_/tag.hpp>
#include <boost/mpl/aux_/nttp_decl.hpp>
#include <boost/mpl/aux_/config/typeof.hpp>
#include <boost/mpl/aux_/config/ctps.hpp>
 
namespace boost { namespace mpl {
 
#if defined(BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES)
 
template<>
struct front_impl< aux::vector_tag >
{
    template< typename Vector > struct apply
        : v_at<Vector,0>
    {
    };
};
 
#else
 
#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
 
template< BOOST_MPL_AUX_NTTP_DECL(long, n_) >
struct front_impl< aux::vector_tag<n_> >
{
    template< typename Vector > struct apply
    {
        typedef typename Vector::item0 type;
    };
};
 
#endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
 
#endif // BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES
 
}}
 
#endif // BOOST_MPL_VECTOR_AUX_FRONT_HPP_INCLUDED