vector/aux_/front.hpp

0001
0002 #ifndef BOOST_MPL_VECTOR_AUX_FRONT_HPP_INCLUDED
0003 #define BOOST_MPL_VECTOR_AUX_FRONT_HPP_INCLUDED
0004
0005 // Copyright Aleksey Gurtovoy 2000-2008
0006 //
0007 // Distributed under the Boost Software License, Version 1.0.
0008 // (See accompanying file LICENSE_1_0.txt or copy at
0009 // http://www.boost.org/LICENSE_1_0.txt)
0010 //
0011 // See http://www.boost.org/libs/mpl for documentation.
0012
0013 // $Id$
0014 // $Date$
0015 // $Revision$
0016
0017 #include <boost/mpl/front_fwd.hpp>
0018 #include <boost/mpl/vector/aux_/at.hpp>
0019 #include <boost/mpl/vector/aux_/tag.hpp>
0020 #include <boost/mpl/aux_/nttp_decl.hpp>
0021 #include <boost/mpl/aux_/config/typeof.hpp>
0022 #include <boost/mpl/aux_/config/ctps.hpp>
0023
0024 namespace boost { namespace mpl {
0025
0026 #if defined(BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES)
0027
0028 template<>
0029 struct front_impl< aux::vector_tag >
0030 {
0031     template< typename Vector > struct apply
0032         : v_at<Vector,0>
0033     {
0034     };
0035 };
0036
0037 #else
0038
0039 #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
0040
0041 template< BOOST_MPL_AUX_NTTP_DECL(long, n_) >
0042 struct front_impl< aux::vector_tag<n_> >
0043 {
0044     template< typename Vector > struct apply
0045     {
0046         typedef typename Vector::item0 type;
0047     };
0048 };
0049
0050 #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
0051
0052 #endif // BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES
0053
0054 }}
0055
0056 #endif // BOOST_MPL_VECTOR_AUX_FRONT_HPP_INCLUDED