[857] | 1 | //-----------------------------------------------------------------------------
|
---|
| 2 | // boost variant/detail/enable_recursive_fwd.hpp header file
|
---|
| 3 | // See http://www.boost.org for updates, documentation, and revision history.
|
---|
| 4 | //-----------------------------------------------------------------------------
|
---|
| 5 | //
|
---|
| 6 | // Copyright (c) 2003
|
---|
| 7 | // Eric Friedman
|
---|
| 8 | //
|
---|
| 9 | // Distributed under the Boost Software License, Version 1.0. (See
|
---|
| 10 | // accompanying file LICENSE_1_0.txt or copy at
|
---|
| 11 | // http://www.boost.org/LICENSE_1_0.txt)
|
---|
| 12 |
|
---|
| 13 | #ifndef BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_FWD_HPP
|
---|
| 14 | #define BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_FWD_HPP
|
---|
| 15 |
|
---|
| 16 | #include "boost/mpl/aux_/config/ctps.hpp"
|
---|
| 17 |
|
---|
| 18 | #include "boost/mpl/bool_fwd.hpp"
|
---|
| 19 |
|
---|
| 20 | #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
|
---|
| 21 | # include "boost/mpl/bool.hpp"
|
---|
| 22 | #else
|
---|
| 23 | # include "boost/type_traits/is_base_and_derived.hpp"
|
---|
| 24 | #endif
|
---|
| 25 |
|
---|
| 26 | namespace boost {
|
---|
| 27 | namespace detail { namespace variant {
|
---|
| 28 |
|
---|
| 29 | ///////////////////////////////////////////////////////////////////////////////
|
---|
| 30 | // (detail) tag recursive_flag
|
---|
| 31 | //
|
---|
| 32 | // Signifies that the variant should perform recursive substituion.
|
---|
| 33 | //
|
---|
| 34 |
|
---|
| 35 | #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
|
---|
| 36 |
|
---|
| 37 | template <typename T>
|
---|
| 38 | struct recursive_flag
|
---|
| 39 | {
|
---|
| 40 | typedef T type;
|
---|
| 41 | };
|
---|
| 42 |
|
---|
| 43 | #else // defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
|
---|
| 44 |
|
---|
| 45 | struct recursive_flag_tag
|
---|
| 46 | {
|
---|
| 47 | };
|
---|
| 48 |
|
---|
| 49 | template <typename T>
|
---|
| 50 | struct recursive_flag
|
---|
| 51 | : recursive_flag_tag
|
---|
| 52 | {
|
---|
| 53 | typedef T type;
|
---|
| 54 | };
|
---|
| 55 |
|
---|
| 56 | #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION workaround
|
---|
| 57 |
|
---|
| 58 | ///////////////////////////////////////////////////////////////////////////////
|
---|
| 59 | // (detail) metafunction is_recursive_flag
|
---|
| 60 | //
|
---|
| 61 | // Signifies that the variant should perform recursive substituion.
|
---|
| 62 | //
|
---|
| 63 |
|
---|
| 64 | #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
|
---|
| 65 |
|
---|
| 66 | template <typename T>
|
---|
| 67 | struct is_recursive_flag
|
---|
| 68 | : mpl::false_
|
---|
| 69 | {
|
---|
| 70 | };
|
---|
| 71 |
|
---|
| 72 | template <typename T>
|
---|
| 73 | struct is_recursive_flag< recursive_flag<T> >
|
---|
| 74 | : mpl::true_
|
---|
| 75 | {
|
---|
| 76 | };
|
---|
| 77 |
|
---|
| 78 | #else // defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
|
---|
| 79 |
|
---|
| 80 | template <typename T>
|
---|
| 81 | struct is_recursive_flag
|
---|
| 82 | : is_base_and_derived< recursive_flag_tag,T >
|
---|
| 83 | {
|
---|
| 84 | };
|
---|
| 85 |
|
---|
| 86 | #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION workaround
|
---|
| 87 |
|
---|
| 88 | ///////////////////////////////////////////////////////////////////////////////
|
---|
| 89 | // (detail) metafunction enable_recursive
|
---|
| 90 | //
|
---|
| 91 | // Attempts recursive_variant_ tag substitution, wrapping with
|
---|
| 92 | // boost::recursive_wrapper if substituion occurs w/ non-indirect result
|
---|
| 93 | // (i.e., not a reference or pointer) *and* NoWrapper is false_.
|
---|
| 94 | //
|
---|
| 95 | template <
|
---|
| 96 | typename T
|
---|
| 97 | , typename RecursiveVariant
|
---|
| 98 | , typename NoWrapper = mpl::false_
|
---|
| 99 | >
|
---|
| 100 | struct enable_recursive;
|
---|
| 101 |
|
---|
| 102 | ///////////////////////////////////////////////////////////////////////////////
|
---|
| 103 | // (detail) metafunction class quoted_enable_recursive
|
---|
| 104 | //
|
---|
| 105 | // Same behavior as enable_recursive metafunction (see above).
|
---|
| 106 | //
|
---|
| 107 | template <
|
---|
| 108 | typename RecursiveVariant
|
---|
| 109 | , typename NoWrapper = mpl::false_
|
---|
| 110 | >
|
---|
| 111 | struct quoted_enable_recursive;
|
---|
| 112 |
|
---|
| 113 | }} // namespace detail::variant
|
---|
| 114 | } // namespace boost
|
---|
| 115 |
|
---|
| 116 | #endif // BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_FWD_HPP
|
---|