/Src/Dependencies/Boost/boost/variant/variant_fwd.hpp
http://hadesmem.googlecode.com/ · C++ Header · 253 lines · 91 code · 42 blank · 120 comment · 3 complexity · 94e2f8fe3e8d53a8a04f2334278919af MD5 · raw file
- //-----------------------------------------------------------------------------
- // boost variant/variant_fwd.hpp header file
- // See http://www.boost.org for updates, documentation, and revision history.
- //-----------------------------------------------------------------------------
- //
- // Copyright (c) 2003
- // Eric Friedman, Itay Maman
- //
- // Distributed under the Boost Software License, Version 1.0. (See
- // accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt)
- #ifndef BOOST_VARIANT_VARIANT_FWD_HPP
- #define BOOST_VARIANT_VARIANT_FWD_HPP
- #include "boost/variant/detail/config.hpp"
- #include "boost/blank_fwd.hpp"
- #include "boost/mpl/arg.hpp"
- #include "boost/mpl/limits/arity.hpp"
- #include "boost/mpl/aux_/na.hpp"
- #include "boost/preprocessor/cat.hpp"
- #include "boost/preprocessor/enum.hpp"
- #include "boost/preprocessor/enum_params.hpp"
- #include "boost/preprocessor/enum_shifted_params.hpp"
- #include "boost/preprocessor/repeat.hpp"
- ///////////////////////////////////////////////////////////////////////////////
- // macro BOOST_VARIANT_LIMIT_TYPES
- //
- // Implementation-defined preprocessor symbol describing the actual
- // length of variant's pseudo-variadic template parameter list.
- //
- #include "boost/mpl/limits/list.hpp"
- #define BOOST_VARIANT_LIMIT_TYPES \
- BOOST_MPL_LIMIT_LIST_SIZE
- ///////////////////////////////////////////////////////////////////////////////
- // macro BOOST_VARIANT_NO_REFERENCE_SUPPORT
- //
- // Defined if variant does not support references as bounded types.
- //
- #if defined(BOOST_VARIANT_AUX_BROKEN_CONSTRUCTOR_TEMPLATE_ORDERING) \
- && !defined(BOOST_VARIANT_AUX_HAS_CONSTRUCTOR_TEMPLATE_ORDERING_SFINAE_WKND) \
- && !defined(BOOST_VARIANT_NO_REFERENCE_SUPPORT)
- # define BOOST_VARIANT_NO_REFERENCE_SUPPORT
- #endif
- ///////////////////////////////////////////////////////////////////////////////
- // macro BOOST_VARIANT_NO_TYPE_SEQUENCE_SUPPORT
- //
- // Defined if variant does not support make_variant_over (see below).
- //
- #if defined(BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE)
- # define BOOST_VARIANT_NO_TYPE_SEQUENCE_SUPPORT
- #endif
- ///////////////////////////////////////////////////////////////////////////////
- // macro BOOST_VARIANT_NO_FULL_RECURSIVE_VARIANT_SUPPORT
- //
- // Defined if make_recursive_variant cannot be supported as documented.
- //
- // Note: Currently, MPL lambda facility is used as workaround if defined, and
- // so only types declared w/ MPL lambda workarounds will work.
- //
- #include "boost/variant/detail/substitute_fwd.hpp"
- #if defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE) \
- && !defined(BOOST_VARIANT_NO_FULL_RECURSIVE_VARIANT_SUPPORT)
- # define BOOST_VARIANT_NO_FULL_RECURSIVE_VARIANT_SUPPORT
- #endif
- ///////////////////////////////////////////////////////////////////////////////
- // macro BOOST_VARIANT_RECURSIVE_VARIANT_MAX_ARITY
- //
- // Exposes maximum allowed arity of class templates with recursive_variant
- // arguments. That is,
- // make_recursive_variant< ..., T<[1], recursive_variant_, ... [N]> >.
- //
- #include "boost/mpl/limits/arity.hpp"
- #define BOOST_VARIANT_RECURSIVE_VARIANT_MAX_ARITY \
- BOOST_MPL_LIMIT_METAFUNCTION_ARITY
- ///////////////////////////////////////////////////////////////////////////////
- // macro BOOST_VARIANT_ENUM_PARAMS
- //
- // Convenience macro for enumeration of BOOST_VARIANT_LIMIT_TYPES params.
- //
- // Rationale: Cleaner, simpler code for clients of variant library.
- //
- #define BOOST_VARIANT_ENUM_PARAMS( param ) \
- BOOST_PP_ENUM_PARAMS(BOOST_VARIANT_LIMIT_TYPES, param)
- ///////////////////////////////////////////////////////////////////////////////
- // macro BOOST_VARIANT_ENUM_SHIFTED_PARAMS
- //
- // Convenience macro for enumeration of BOOST_VARIANT_LIMIT_TYPES-1 params.
- //
- #define BOOST_VARIANT_ENUM_SHIFTED_PARAMS( param ) \
- BOOST_PP_ENUM_SHIFTED_PARAMS(BOOST_VARIANT_LIMIT_TYPES, param)
- namespace boost {
- namespace detail { namespace variant {
- ///////////////////////////////////////////////////////////////////////////////
- // (detail) class void_ and class template convert_void
- //
- // Provides the mechanism by which void(NN) types are converted to
- // mpl::void_ (and thus can be passed to mpl::list).
- //
- // Rationale: This is particularly needed for the using-declarations
- // workaround (below), but also to avoid associating mpl namespace with
- // variant in argument dependent lookups (which used to happen because of
- // defaulting of template parameters to mpl::void_).
- //
- struct void_;
- template <typename T>
- struct convert_void
- {
- typedef T type;
- };
- template <>
- struct convert_void< void_ >
- {
- typedef mpl::na type;
- };
- ///////////////////////////////////////////////////////////////////////////////
- // (workaround) BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE
- //
- // Needed to work around compilers that don't support using-declaration
- // overloads. (See the variant::initializer workarounds below.)
- //
- #if defined(BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE)
- // (detail) tags voidNN -- NN defined on [0, BOOST_VARIANT_LIMIT_TYPES)
- //
- // Defines void types that are each unique and specializations of
- // convert_void that yields mpl::na for each voidNN type.
- //
- #define BOOST_VARIANT_DETAIL_DEFINE_VOID_N(z,N,_) \
- struct BOOST_PP_CAT(void,N); \
- \
- template <> \
- struct convert_void< BOOST_PP_CAT(void,N) > \
- { \
- typedef mpl::na type; \
- }; \
- /**/
- BOOST_PP_REPEAT(
- BOOST_VARIANT_LIMIT_TYPES
- , BOOST_VARIANT_DETAIL_DEFINE_VOID_N
- , _
- )
- #undef BOOST_VARIANT_DETAIL_DEFINE_VOID_N
- #endif // BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE workaround
- }} // namespace detail::variant
- ///////////////////////////////////////////////////////////////////////////////
- // (detail) macro BOOST_VARIANT_AUX_DECLARE_PARAM
- //
- // Template parameter list for variant and recursive_variant declarations.
- //
- #if !defined(BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE)
- # define BOOST_VARIANT_AUX_DECLARE_PARAMS_IMPL(z, N, T) \
- typename BOOST_PP_CAT(T,N) = detail::variant::void_ \
- /**/
- #else // defined(BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE)
- # define BOOST_VARIANT_AUX_DECLARE_PARAMS_IMPL(z, N, T) \
- typename BOOST_PP_CAT(T,N) = BOOST_PP_CAT(detail::variant::void,N) \
- /**/
- #endif // BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE workaround
- #define BOOST_VARIANT_AUX_DECLARE_PARAMS \
- BOOST_PP_ENUM( \
- BOOST_VARIANT_LIMIT_TYPES \
- , BOOST_VARIANT_AUX_DECLARE_PARAMS_IMPL \
- , T \
- ) \
- /**/
- ///////////////////////////////////////////////////////////////////////////////
- // class template variant (concept inspired by Andrei Alexandrescu)
- //
- // Efficient, type-safe bounded discriminated union.
- //
- // Preconditions:
- // - Each type must be unique.
- // - No type may be const-qualified.
- //
- // Proper declaration form:
- // variant<types> (where types is a type-sequence)
- // or
- // variant<T0,T1,...,Tn> (where T0 is NOT a type-sequence)
- //
- template < BOOST_VARIANT_AUX_DECLARE_PARAMS > class variant;
- ///////////////////////////////////////////////////////////////////////////////
- // metafunction make_recursive_variant
- //
- // Exposes a boost::variant with recursive_variant_ tags (below) substituted
- // with the variant itself (wrapped as needed with boost::recursive_wrapper).
- //
- template < BOOST_VARIANT_AUX_DECLARE_PARAMS > struct make_recursive_variant;
- #undef BOOST_VARIANT_AUX_DECLARE_PARAMS_IMPL
- #undef BOOST_VARIANT_AUX_DECLARE_PARAMS
- ///////////////////////////////////////////////////////////////////////////////
- // type recursive_variant_
- //
- // Tag type indicates where recursive variant substitution should occur.
- //
- #if !defined(BOOST_VARIANT_NO_FULL_RECURSIVE_VARIANT_SUPPORT)
- struct recursive_variant_ {};
- #else
- typedef mpl::arg<1> recursive_variant_;
- #endif
- ///////////////////////////////////////////////////////////////////////////////
- // metafunction make_variant_over
- //
- // Result is a variant w/ types of the specified type sequence.
- //
- template <typename Types> struct make_variant_over;
- ///////////////////////////////////////////////////////////////////////////////
- // metafunction make_recursive_variant_over
- //
- // Result is a recursive variant w/ types of the specified type sequence.
- //
- template <typename Types> struct make_recursive_variant_over;
- } // namespace boost
- #endif // BOOST_VARIANT_VARIANT_FWD_HPP