]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | //----------------------------------------------------------------------------- |
2 | // boost variant/detail/enable_recursive.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_HPP | |
14 | #define BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_HPP | |
15 | ||
16 | #include <boost/variant/detail/enable_recursive_fwd.hpp> | |
17 | #include <boost/variant/variant_fwd.hpp> | |
18 | ||
19 | #if !defined(BOOST_VARIANT_NO_FULL_RECURSIVE_VARIANT_SUPPORT) | |
20 | # include <boost/mpl/apply.hpp> | |
21 | # include <boost/mpl/eval_if.hpp> | |
22 | # include <boost/mpl/lambda.hpp> | |
23 | #endif | |
24 | ||
25 | #include <boost/variant/detail/substitute.hpp> | |
26 | #include <boost/mpl/aux_/config/ctps.hpp> | |
27 | #include <boost/mpl/bool_fwd.hpp> | |
28 | #include <boost/mpl/if.hpp> | |
29 | #include <boost/mpl/or.hpp> | |
30 | #include <boost/type_traits/is_pointer.hpp> | |
31 | #include <boost/type_traits/is_reference.hpp> | |
32 | #include <boost/type_traits/is_same.hpp> | |
33 | ||
34 | #include <boost/variant/recursive_wrapper.hpp> | |
35 | ||
36 | namespace boost { | |
37 | namespace detail { namespace variant { | |
38 | ||
39 | #if !defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE) | |
40 | ||
41 | # define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL(T,Dest,Source) \ | |
42 | substitute< T , Dest , Source > \ | |
43 | /**/ | |
44 | ||
45 | #else // defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE) | |
46 | ||
47 | /////////////////////////////////////////////////////////////////////////////// | |
48 | // (detail) class template rebind1 | |
49 | // | |
50 | // Limited workaround in case 'substitute' metafunction unavailable. | |
51 | // | |
52 | ||
53 | template <typename T, typename U1> | |
54 | struct rebind1 | |
55 | { | |
56 | private: | |
57 | typedef typename mpl::lambda< | |
58 | mpl::identity<T> | |
59 | >::type le_; | |
60 | ||
61 | public: | |
62 | typedef typename mpl::eval_if< | |
63 | is_same< le_, mpl::identity<T> > | |
64 | , le_ // identity<T> | |
65 | , mpl::apply1<le_, U1> | |
66 | >::type type; | |
67 | }; | |
68 | ||
69 | # define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL(T,Dest,Source) \ | |
70 | rebind1< T , Dest > \ | |
71 | /**/ | |
72 | ||
73 | #endif // !defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE) | |
74 | ||
75 | /////////////////////////////////////////////////////////////////////////////// | |
76 | // (detail) metafunction enable_recursive | |
77 | // | |
78 | // See boost/variant/detail/enable_recursive_fwd.hpp for more information. | |
79 | // | |
80 | ||
81 | ||
82 | template <typename T, typename RecursiveVariant, typename NoWrapper> | |
83 | struct enable_recursive | |
84 | : BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL( | |
85 | T, RecursiveVariant, ::boost::recursive_variant_ | |
86 | ) | |
87 | { | |
88 | }; | |
89 | ||
90 | template <typename T, typename RecursiveVariant> | |
91 | struct enable_recursive< T,RecursiveVariant,mpl::false_ > | |
92 | { | |
93 | private: // helpers, for metafunction result (below) | |
94 | ||
95 | typedef typename BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL( | |
96 | T, RecursiveVariant, ::boost::recursive_variant_ | |
97 | )::type t_; | |
98 | ||
99 | public: // metafunction result | |
100 | ||
101 | // [Wrap with recursive_wrapper only if rebind really changed something:] | |
102 | typedef typename mpl::if_< | |
103 | mpl::or_< | |
104 | is_same< t_,T > | |
105 | , is_reference<t_> | |
106 | , is_pointer<t_> | |
107 | > | |
108 | , t_ | |
109 | , boost::recursive_wrapper<t_> | |
110 | >::type type; | |
111 | ||
112 | }; | |
113 | ||
114 | ||
115 | /////////////////////////////////////////////////////////////////////////////// | |
116 | // (detail) metafunction class quoted_enable_recursive | |
117 | // | |
118 | // Same behavior as enable_recursive metafunction (see above). | |
119 | // | |
120 | template <typename RecursiveVariant, typename NoWrapper> | |
121 | struct quoted_enable_recursive | |
122 | { | |
123 | template <typename T> | |
124 | struct apply | |
125 | : enable_recursive<T, RecursiveVariant, NoWrapper> | |
126 | { | |
127 | }; | |
128 | }; | |
129 | ||
130 | }} // namespace detail::variant | |
131 | } // namespace boost | |
132 | ||
133 | #endif // BOOST_VARIANT_DETAIL_ENABLE_RECURSIVE_HPP |