1 /*============================================================================= 2 Copyright (c) 2001-2011 Joel de Guzman 3 4 Distributed under the Boost Software License, Version 1.0. (See accompanying 5 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 6 ==============================================================================*/ 7 #ifndef BOOST_PP_IS_ITERATING 8 #if !defined(BOOST_SPIRIT_AS_VARIANT_NOVEMBER_16_2007_0420PM) 9 #define BOOST_SPIRIT_AS_VARIANT_NOVEMBER_16_2007_0420PM 10 11 #include <boost/preprocessor/iterate.hpp> 12 #include <boost/preprocessor/repetition/enum_params.hpp> 13 #include <boost/preprocessor/repetition/enum_binary_params.hpp> 14 #include <boost/preprocessor/repetition/enum_params_with_a_default.hpp> 15 #include <boost/preprocessor/repetition/repeat_from_to.hpp> 16 #include <boost/variant/variant_fwd.hpp> 17 #include <boost/fusion/include/size.hpp> 18 #include <boost/fusion/include/begin.hpp> 19 #include <boost/fusion/include/next.hpp> 20 #include <boost/fusion/include/value_of.hpp> 21 #include <boost/mpl/fold.hpp> 22 #include <boost/mpl/vector.hpp> 23 #include <boost/mpl/push_back.hpp> 24 #include <boost/mpl/equal_to.hpp> 25 #include <boost/mpl/contains.hpp> 26 #include <boost/mpl/limits/list.hpp> 27 #include <boost/type_traits/is_same.hpp> 28 29 namespace boost { namespace spirit { namespace detail 30 { 31 template <int size> 32 struct as_variant_impl; 33 34 #if !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES) 35 #else 36 template <> 37 struct as_variant_impl<0> 38 { 39 template <typename Iterator> 40 struct apply 41 { 42 typedef variant<> type; 43 }; 44 }; 45 #endif 46 47 #define BOOST_FUSION_NEXT_ITERATOR(z, n, data) \ 48 typedef typename fusion::result_of::next<BOOST_PP_CAT(I, n)>::type \ 49 BOOST_PP_CAT(I, BOOST_PP_INC(n)); 50 51 #define BOOST_FUSION_NEXT_CALL_ITERATOR(z, n, data) \ 52 typename gen::BOOST_PP_CAT(I, BOOST_PP_INC(n)) \ 53 BOOST_PP_CAT(i, BOOST_PP_INC(n)) = fusion::next(BOOST_PP_CAT(i, n)); 54 55 #define BOOST_FUSION_VALUE_OF_ITERATOR(z, n, data) \ 56 typedef typename fusion::result_of::value_of<BOOST_PP_CAT(I, n)>::type \ 57 BOOST_PP_CAT(T, n); 58 59 #define BOOST_PP_FILENAME_1 <boost/spirit/home/support/detail/as_variant.hpp> 60 61 #if !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES) 62 #define BOOST_PP_ITERATION_LIMITS (1, BOOST_MPL_LIMIT_LIST_SIZE) 63 #else 64 #define BOOST_PP_ITERATION_LIMITS (1, BOOST_VARIANT_LIMIT_TYPES) 65 #endif 66 67 #include BOOST_PP_ITERATE() 68 69 #undef BOOST_FUSION_NEXT_ITERATOR 70 #undef BOOST_FUSION_NEXT_CALL_ITERATOR 71 #undef BOOST_FUSION_VALUE_OF_ITERATOR 72 73 template <typename Sequence> 74 struct as_variant 75 { 76 // build a variant generator being able to generate a variant holding 77 // all of the types as given in the typelist 78 typedef typename 79 detail::as_variant_impl<fusion::result_of::size<Sequence>::value> 80 gen; 81 82 // use this generator to create the actual variant 83 typedef typename gen::template apply< 84 typename fusion::result_of::begin<Sequence>::type 85 >::type 86 type; 87 }; 88 }}} 89 90 #endif 91 #else // defined(BOOST_PP_IS_ITERATING) 92 /////////////////////////////////////////////////////////////////////////////// 93 // 94 // Preprocessor vertical repetition code 95 // 96 /////////////////////////////////////////////////////////////////////////////// 97 98 #define N BOOST_PP_ITERATION() 99 100 template <> 101 struct as_variant_impl<N> 102 { 103 template <typename I0> 104 struct apply 105 { 106 BOOST_PP_REPEAT(N, BOOST_FUSION_NEXT_ITERATOR, _) 107 BOOST_PP_REPEAT(N, BOOST_FUSION_VALUE_OF_ITERATOR, _) 108 typedef variant<BOOST_PP_ENUM_PARAMS(N, T)> type; 109 }; 110 }; 111 112 #undef N 113 #endif // defined(BOOST_PP_IS_ITERATING) 114 115