2 #if !defined(BOOST_PP_IS_ITERATING)
6 //-----------------------------------------------------------------------------
7 // boost variant/detail/substitute.hpp header file
8 // See http://www.boost.org for updates, documentation, and revision history.
9 //-----------------------------------------------------------------------------
14 // Distributed under the Boost Software License, Version 1.0. (See
15 // accompanying file LICENSE_1_0.txt or copy at
16 // http://www.boost.org/LICENSE_1_0.txt)
18 #ifndef BOOST_VARIANT_DETAIL_SUBSTITUTE_HPP
19 #define BOOST_VARIANT_DETAIL_SUBSTITUTE_HPP
21 #include <boost/mpl/aux_/config/ctps.hpp>
23 #include <boost/variant/detail/substitute_fwd.hpp>
24 #include <boost/variant/variant_fwd.hpp> // for BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES
25 #include <boost/mpl/aux_/lambda_arity_param.hpp>
26 #include <boost/mpl/aux_/preprocessor/params.hpp>
27 #include <boost/mpl/aux_/preprocessor/repeat.hpp>
28 #include <boost/mpl/int_fwd.hpp>
29 #include <boost/mpl/limits/arity.hpp>
30 #include <boost/preprocessor/cat.hpp>
31 #include <boost/preprocessor/empty.hpp>
32 #include <boost/preprocessor/arithmetic/inc.hpp>
33 #include <boost/preprocessor/iterate.hpp>
36 namespace detail { namespace variant {
38 #if !defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE)
40 ///////////////////////////////////////////////////////////////////////////////
41 // (detail) metafunction substitute
43 // Substitutes one type for another in the given type expression.
50 typename T, typename Dest, typename Source
51 BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(
52 typename Arity /* = ... (see substitute_fwd.hpp) */
61 // tag substitution specializations
64 #define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG(CV_) \
65 template <typename Dest, typename Source> \
70 BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(mpl::int_<-1>) \
73 typedef CV_ Dest type; \
77 BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG( BOOST_PP_EMPTY() )
78 BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG(const)
79 BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG(volatile)
80 BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG(const volatile)
82 #undef BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG
85 // pointer specializations
87 #define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER(CV_) \
88 template <typename T, typename Dest, typename Source> \
93 BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(mpl::int_<-1>) \
96 typedef typename substitute< \
102 BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER( BOOST_PP_EMPTY() )
103 BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER(const)
104 BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER(volatile)
105 BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER(const volatile)
107 #undef BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER
110 // reference specializations
112 template <typename T, typename Dest, typename Source>
117 BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(mpl::int_<-1>)
120 typedef typename substitute<
126 // template expression (i.e., F<...>) specializations
129 #if !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES)
131 template <typename...> class F
135 BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(typename Arity)
141 BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(Arity)
144 typedef F<typename substitute<
148 #endif // !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES)
150 #define BOOST_VARIANT_AUX_SUBSTITUTE_TYPEDEF_IMPL(N) \
151 typedef typename substitute< \
152 BOOST_PP_CAT(U,N), Dest, Source \
153 >::type BOOST_PP_CAT(u,N); \
156 #define BOOST_VARIANT_AUX_SUBSTITUTE_TYPEDEF(z, N, _) \
157 BOOST_VARIANT_AUX_SUBSTITUTE_TYPEDEF_IMPL( BOOST_PP_INC(N) ) \
160 #define BOOST_PP_ITERATION_LIMITS (0,BOOST_MPL_LIMIT_METAFUNCTION_ARITY)
161 #define BOOST_PP_FILENAME_1 <boost/variant/detail/substitute.hpp>
162 #include BOOST_PP_ITERATE()
164 #undef BOOST_VARIANT_AUX_SUBSTITUTE_TYPEDEF_IMPL
165 #undef BOOST_VARIANT_AUX_SUBSTITUTE_TYPEDEF
167 #endif // !defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE)
169 }} // namespace detail::variant
172 #endif // BOOST_VARIANT_DETAIL_SUBSTITUTE_HPP
174 ///// iteration, depth == 1
176 #elif BOOST_PP_ITERATION_DEPTH() == 1
177 #define i BOOST_PP_FRAME_ITERATION(1)
182 // template specializations
185 template < BOOST_MPL_PP_PARAMS(i,typename P) > class T
186 , BOOST_MPL_PP_PARAMS(i,typename U)
191 T< BOOST_MPL_PP_PARAMS(i,U) >
194 BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(mpl::int_<( i )>)
198 BOOST_MPL_PP_REPEAT(i, BOOST_VARIANT_AUX_SUBSTITUTE_TYPEDEF, _)
201 typedef T< BOOST_MPL_PP_PARAMS(i,u) > type;
205 // function specializations
209 , BOOST_MPL_PP_PARAMS(i,typename U)
214 R (*)( BOOST_MPL_PP_PARAMS(i,U) )
217 BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(mpl::int_<-1>)
221 typedef typename substitute< R, Dest, Source >::type r;
222 BOOST_MPL_PP_REPEAT(i, BOOST_VARIANT_AUX_SUBSTITUTE_TYPEDEF, _)
225 typedef r (*type)( BOOST_MPL_PP_PARAMS(i,u) );
231 // zero-arg function specialization
234 typename R, typename Dest, typename Source
240 BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(mpl::int_<-1>)
244 typedef typename substitute< R, Dest, Source >::type r;
247 typedef r (*type)( void );
253 #endif // BOOST_PP_IS_ITERATING