Chris@16: //-----------------------------------------------------------------------------
Chris@16: // boost variant/detail/enable_recursive_fwd.hpp header file
Chris@16: // See http://www.boost.org for updates, documentation, and revision history.
Chris@16: //-----------------------------------------------------------------------------
Chris@16: //
Chris@16: // Copyright (c) 2003
Chris@16: // Eric Friedman
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See
Chris@16: // accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_FWD_HPP
Chris@16: #define BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_FWD_HPP
Chris@16: 
Chris@16: #include "boost/mpl/aux_/config/ctps.hpp"
Chris@16: 
Chris@16: #include "boost/mpl/bool_fwd.hpp"
Chris@16: 
Chris@16: #   include "boost/mpl/bool.hpp"
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace detail { namespace variant {
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // (detail) tag recursive_flag
Chris@16: //
Chris@16: // Signifies that the variant should perform recursive substituion.
Chris@16: //
Chris@16: 
Chris@16: 
Chris@16: template <typename T>
Chris@16: struct recursive_flag
Chris@16: {
Chris@16:     typedef T type;
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // (detail) metafunction is_recursive_flag
Chris@16: //
Chris@16: // Signifies that the variant should perform recursive substituion.
Chris@16: //
Chris@16: 
Chris@16: 
Chris@16: template <typename T>
Chris@16: struct is_recursive_flag
Chris@16:     : mpl::false_
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template <typename T>
Chris@16: struct is_recursive_flag< recursive_flag<T> >
Chris@16:     : mpl::true_
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // (detail) metafunction enable_recursive
Chris@16: //
Chris@16: // Attempts recursive_variant_ tag substitution, wrapping with
Chris@16: // boost::recursive_wrapper if substituion occurs w/ non-indirect result
Chris@16: // (i.e., not a reference or pointer) *and* NoWrapper is false_.
Chris@16: //
Chris@16: template <
Chris@16:       typename T
Chris@16:     , typename RecursiveVariant
Chris@16:     , typename NoWrapper = mpl::false_
Chris@16:     >
Chris@16: struct enable_recursive;
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // (detail) metafunction class quoted_enable_recursive
Chris@16: //
Chris@16: // Same behavior as enable_recursive metafunction (see above).
Chris@16: //
Chris@16: template <
Chris@16:       typename RecursiveVariant
Chris@16:     , typename NoWrapper = mpl::false_
Chris@16:     >
Chris@16: struct quoted_enable_recursive;
Chris@16: 
Chris@16: }} // namespace detail::variant
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #endif // BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_FWD_HPP