1 2 #ifndef BOOST_MPL_SEQUENCE_TAG_HPP_INCLUDED 3 #define BOOST_MPL_SEQUENCE_TAG_HPP_INCLUDED 4 5 // Copyright Aleksey Gurtovoy 2000-2004 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: sequence_tag.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/sequence_tag_fwd.hpp> 18 #include <boost/mpl/aux_/has_tag.hpp> 19 #include <boost/mpl/aux_/has_begin.hpp> 20 #include <boost/mpl/aux_/na_spec.hpp> 21 #include <boost/mpl/aux_/is_msvc_eti_arg.hpp> 22 #include <boost/mpl/aux_/config/eti.hpp> 23 #include <boost/mpl/aux_/yes_no.hpp> 24 #include <boost/mpl/aux_/config/workaround.hpp> 25 26 namespace boost { namespace mpl { 27 28 // agurt, 27/nov/02: have to use a simplistic 'sequence_tag' implementation 29 // on MSVC to avoid dreadful "internal structure overflow" error 30 #if BOOST_WORKAROUND(BOOST_MSVC, < 1300) \ 31 || defined(BOOST_MPL_CFG_NO_HAS_XXX) 32 33 template< 34 typename BOOST_MPL_AUX_NA_PARAM(Sequence) 35 > 36 struct sequence_tag 37 { 38 typedef typename Sequence::tag type; 39 }; 40 41 #elif BOOST_WORKAROUND(BOOST_MSVC, == 1300) 42 43 // agurt, 07/feb/03: workaround for what seems to be MSVC 7.0-specific ETI issue 44 45 namespace aux { 46 47 template< bool > 48 struct sequence_tag_impl 49 { 50 template< typename Sequence > struct result_ 51 { 52 typedef typename Sequence::tag type; 53 }; 54 }; 55 56 template<> 57 struct sequence_tag_impl<false> 58 { 59 template< typename Sequence > struct result_ 60 { 61 typedef int type; 62 }; 63 }; 64 65 } // namespace aux 66 67 template< 68 typename BOOST_MPL_AUX_NA_PARAM(Sequence) 69 > 70 struct sequence_tag 71 : aux::sequence_tag_impl< !aux::is_msvc_eti_arg<Sequence>::value > 72 ::template result_<Sequence> 73 { 74 }; 75 76 #else 77 78 namespace aux { 79 80 template< bool has_tag_, bool has_begin_ > 81 struct sequence_tag_impl 82 { 83 // agurt 24/nov/02: MSVC 6.5 gets confused in 'sequence_tag_impl<true>' 84 // specialization below, if we name it 'result_' here 85 template< typename Sequence > struct result2_; 86 }; 87 88 # define AUX_CLASS_SEQUENCE_TAG_SPEC(has_tag, has_begin, result_type) \ 89 template<> struct sequence_tag_impl<has_tag,has_begin> \ 90 { \ 91 template< typename Sequence > struct result2_ \ 92 { \ 93 typedef result_type type; \ 94 }; \ 95 }; \ 96 /**/ 97 98 AUX_CLASS_SEQUENCE_TAG_SPEC(true, true, typename Sequence::tag) 99 AUX_CLASS_SEQUENCE_TAG_SPEC(true, false, typename Sequence::tag) 100 AUX_CLASS_SEQUENCE_TAG_SPEC(false, true, nested_begin_end_tag) 101 AUX_CLASS_SEQUENCE_TAG_SPEC(false, false, non_sequence_tag) 102 103 # undef AUX_CLASS_SEQUENCE_TAG_SPEC 104 105 } // namespace aux 106 107 template< 108 typename BOOST_MPL_AUX_NA_PARAM(Sequence) 109 > 110 struct sequence_tag 111 : aux::sequence_tag_impl< 112 ::boost::mpl::aux::has_tag<Sequence>::value 113 , ::boost::mpl::aux::has_begin<Sequence>::value 114 >::template result2_<Sequence> 115 { 116 }; 117 118 #endif // BOOST_MSVC 119 120 BOOST_MPL_AUX_NA_SPEC(1, sequence_tag) 121 122 }} 123 124 #endif // BOOST_MPL_SEQUENCE_TAG_HPP_INCLUDED 125