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1 | // Boost.TypeErasure library |
2 | // | |
3 | // Copyright 2012 Steven Watanabe | |
4 | // | |
5 | // Distributed under the Boost Software License Version 1.0. (See | |
6 | // accompanying file LICENSE_1_0.txt or copy at | |
7 | // http://www.boost.org/LICENSE_1_0.txt) | |
8 | // | |
9 | // $Id$ | |
10 | ||
11 | #ifndef BOOST_TYPE_ERASURE_IS_SUBCONCEPT_HPP_INCLUDED | |
12 | #define BOOST_TYPE_ERASURE_IS_SUBCONCEPT_HPP_INCLUDED | |
13 | ||
14 | #include <boost/mpl/bool.hpp> | |
15 | #include <boost/mpl/not.hpp> | |
16 | #include <boost/mpl/if.hpp> | |
17 | #include <boost/mpl/end.hpp> | |
18 | #include <boost/mpl/find_if.hpp> | |
19 | #include <boost/mpl/has_key.hpp> | |
20 | #include <boost/type_traits/is_same.hpp> | |
21 | #include <boost/type_erasure/detail/normalize.hpp> | |
22 | #include <boost/type_erasure/detail/rebind_placeholders.hpp> | |
23 | #include <boost/type_erasure/static_binding.hpp> | |
24 | ||
25 | namespace boost { | |
26 | namespace type_erasure { | |
27 | namespace detail { | |
28 | ||
29 | template<class Sub, class Super, class PlaceholderMap> | |
30 | struct is_subconcept_impl { | |
31 | typedef typename ::boost::type_erasure::detail::normalize_concept< | |
32 | Super>::concept_set super_set; | |
33 | typedef typename ::boost::type_erasure::detail::get_placeholder_normalization_map< | |
34 | Super | |
35 | >::type placeholder_subs_super; | |
36 | ||
37 | typedef typename ::boost::type_erasure::detail::normalize_concept< | |
38 | Sub>::type normalized_sub; | |
39 | typedef typename ::boost::type_erasure::detail::get_placeholder_normalization_map< | |
40 | Sub | |
41 | >::type placeholder_subs_sub; | |
42 | ||
43 | typedef typename ::boost::mpl::eval_if< ::boost::is_same<PlaceholderMap, void>, | |
44 | boost::mpl::identity<void>, | |
45 | ::boost::type_erasure::detail::convert_deductions< | |
46 | PlaceholderMap, | |
47 | placeholder_subs_sub, | |
48 | placeholder_subs_super | |
49 | > | |
50 | >::type bindings; | |
51 | ||
52 | typedef typename ::boost::mpl::if_< ::boost::is_same<PlaceholderMap, void>, | |
53 | ::boost::mpl::_1, | |
54 | ::boost::type_erasure::detail::rebind_placeholders< | |
55 | ::boost::mpl::_1, | |
56 | bindings | |
57 | > | |
58 | >::type transform; | |
59 | ||
60 | typedef typename ::boost::is_same< | |
61 | typename ::boost::mpl::find_if<normalized_sub, | |
62 | ::boost::mpl::not_< | |
63 | ::boost::mpl::has_key< | |
64 | super_set, | |
65 | transform | |
66 | > | |
67 | > | |
68 | >::type, | |
69 | typename ::boost::mpl::end<normalized_sub>::type | |
70 | >::type type; | |
71 | }; | |
72 | ||
73 | } | |
74 | ||
75 | /** | |
76 | * @ref is_subconcept is a boolean metafunction that determines whether | |
77 | * one concept is a sub-concept of another. | |
78 | * | |
79 | * \code | |
80 | * is_subconcept<incrementable<>, incrementable<> > -> true | |
81 | * is_subconcept<incrementable<>, addable<> > -> false | |
82 | * is_subconcept<incrementable<_a>, forward_iterator<_iter>, | |
83 | * mpl::map<mpl::pair<_a, _iter> > > -> true | |
84 | * \endcode | |
85 | * | |
86 | * \tparam Sub The sub concept | |
87 | * \tparam Super The super concept | |
88 | * \tparam PlaceholderMap (optional) An MPL map with keys for | |
89 | * every non-deduced placeholder in Sub. The | |
90 | * associated value of each key is the corresponding placeholder | |
91 | * in Super. If @c PlaceholderMap is omitted, @c Super and @c Sub | |
92 | * are presumed to use the same set of placeholders. | |
93 | */ | |
94 | template<class Sub, class Super, class PlaceholderMap = void> | |
95 | struct is_subconcept : ::boost::type_erasure::detail::is_subconcept_impl<Sub, Super, PlaceholderMap>::type { | |
96 | }; | |
97 | ||
98 | #ifndef BOOST_TYPE_ERASURE_DOXYGEN | |
99 | template<class Sub, class Super, class PlaceholderMap> | |
100 | struct is_subconcept<Sub, Super, static_binding<PlaceholderMap> > : | |
101 | ::boost::type_erasure::detail::is_subconcept_impl<Sub, Super, PlaceholderMap>::type | |
102 | {}; | |
103 | #endif | |
104 | ||
105 | } | |
106 | } | |
107 | ||
108 | #endif |