boost/mpl/vector/aux_/front.hpp

   1
   2 #ifndef BOOST_MPL_VECTOR_AUX_FRONT_HPP_INCLUDED
   3 #define BOOST_MPL_VECTOR_AUX_FRONT_HPP_INCLUDED
   4
   5 // Copyright Aleksey Gurtovoy 2000-2008
   6 //
   7 // Distributed under the Boost Software License, Version 1.0.
   8 // (See accompanying file LICENSE_1_0.txt or copy at
   9 // http://www.boost.org/LICENSE_1_0.txt)
  10 //
  11 // See http://www.boost.org/libs/mpl for documentation.
  12
  13 // $Id: front.hpp 49267 2008-10-11 06:19:02Z agurtovoy $
  14 // $Date: 2008-10-10 23:19:02 -0700 (Fri, 10 Oct 2008) $
  15 // $Revision: 49267 $
  16
  17 #include <boost/mpl/front_fwd.hpp>
  18 #include <boost/mpl/vector/aux_/at.hpp>
  19 #include <boost/mpl/vector/aux_/tag.hpp>
  20 #include <boost/mpl/aux_/nttp_decl.hpp>
  21 #include <boost/mpl/aux_/config/typeof.hpp>
  22 #include <boost/mpl/aux_/config/ctps.hpp>
  23
  24 namespace boost { namespace mpl {
  25
  26 #if defined(BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES)
  27
  28 template<>
  29 struct front_impl< aux::vector_tag >
  30 {
  31     template< typename Vector > struct apply
  32         : v_at<Vector,0>
  33     {
  34     };
  35 };
  36
  37 #else
  38
  39 #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
  40
  41 template< BOOST_MPL_AUX_NTTP_DECL(long, n_) >
  42 struct front_impl< aux::vector_tag<n_> >
  43 {
  44     template< typename Vector > struct apply
  45     {
  46         typedef typename Vector::item0 type;
  47     };
  48 };
  49
  50 #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
  51
  52 #endif // BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES
  53
  54 }}
  55
  56 #endif // BOOST_MPL_VECTOR_AUX_FRONT_HPP_INCLUDED