1 | // Copyright David Abrahams, Daniel Wallin 2003. |
2 | // Distributed under the Boost Software License, Version 1.0. |
3 | // (See accompanying file LICENSE_1_0.txt or copy at |
4 | // http://www.boost.org/LICENSE_1_0.txt) |
5 | |
6 | #ifndef BOOST_PARAMETER_DEDUCED_HPP |
7 | #define BOOST_PARAMETER_DEDUCED_HPP |
8 | |
9 | #include <boost/parameter/aux_/use_default.hpp> |
10 | |
11 | namespace boost { namespace parameter { |
12 | |
13 | // This metafunction can be used to describe the treatment of particular |
14 | // named parameters for the purposes of overload elimination with SFINAE, |
15 | // by placing specializations in the parameters<...> list. |
16 | // |
17 | // If a keyword k is specified with deduced<...>, that keyword |
18 | // will be automatically deduced from the argument list. |
19 | template <typename Tag> |
20 | struct deduced |
21 | { |
22 | typedef Tag key_type; |
23 | }; |
24 | }} |
25 | |
26 | #include <boost/parameter/config.hpp> |
27 | |
28 | #if defined(BOOST_PARAMETER_CAN_USE_MP11) |
29 | #include <boost/mp11/integral.hpp> |
30 | #else |
31 | #include <boost/mpl/bool.hpp> |
32 | #endif |
33 | |
34 | namespace boost { namespace parameter { namespace aux { |
35 | |
36 | template <typename T> |
37 | struct is_deduced_aux |
38 | #if defined(BOOST_PARAMETER_CAN_USE_MP11) |
39 | : ::boost::mp11::mp_false |
40 | #else |
41 | : ::boost::mpl::false_ |
42 | #endif |
43 | { |
44 | }; |
45 | |
46 | template <typename Tag> |
47 | struct is_deduced_aux< ::boost::parameter::deduced<Tag> > |
48 | #if defined(BOOST_PARAMETER_CAN_USE_MP11) |
49 | : ::boost::mp11::mp_true |
50 | #else |
51 | : ::boost::mpl::true_ |
52 | #endif |
53 | { |
54 | }; |
55 | |
56 | template <typename T> |
57 | struct is_deduced0 |
58 | : ::boost::parameter::aux::is_deduced_aux<typename T::key_type>::type |
59 | { |
60 | }; |
61 | }}} // namespace boost::parameter::aux |
62 | |
63 | #include <boost/parameter/required.hpp> |
64 | #include <boost/parameter/optional.hpp> |
65 | |
66 | #if defined(BOOST_PARAMETER_CAN_USE_MP11) |
67 | #include <boost/mp11/utility.hpp> |
68 | #else |
69 | #include <boost/mpl/if.hpp> |
70 | #endif |
71 | |
72 | namespace boost { namespace parameter { namespace aux { |
73 | |
74 | // |
75 | // tag_type, has_default, and predicate -- |
76 | // |
77 | // These metafunctions accept a ParameterSpec and extract the |
78 | // keyword tag, whether or not a default is supplied for the |
79 | // parameter, and the predicate that the corresponding actual |
80 | // argument type is required match. |
81 | // |
82 | // a ParameterSpec is a specialization of either keyword<...>, |
83 | // required<...>, optional<...> |
84 | // |
85 | |
86 | template <typename T> |
87 | #if defined(BOOST_PARAMETER_CAN_USE_MP11) |
88 | using has_default = ::boost::mp11::mp_if< |
89 | ::boost::parameter::aux::is_required<T> |
90 | , ::boost::mp11::mp_false |
91 | , ::boost::mp11::mp_true |
92 | >; |
93 | #else |
94 | struct has_default |
95 | : ::boost::mpl::if_< |
96 | ::boost::parameter::aux::is_required<T> |
97 | , ::boost::mpl::false_ |
98 | , ::boost::mpl::true_ |
99 | >::type |
100 | { |
101 | }; |
102 | #endif |
103 | |
104 | template <typename T> |
105 | #if defined(BOOST_PARAMETER_CAN_USE_MP11) |
106 | using is_deduced = ::boost::mp11::mp_if< |
107 | ::boost::mp11::mp_if< |
108 | ::boost::parameter::aux::is_optional<T> |
109 | , ::boost::mp11::mp_true |
110 | , ::boost::parameter::aux::is_required<T> |
111 | > |
112 | , ::boost::parameter::aux::is_deduced0<T> |
113 | , ::boost::mp11::mp_false |
114 | >; |
115 | #else |
116 | struct is_deduced |
117 | : ::boost::mpl::if_< |
118 | typename ::boost::mpl::if_< |
119 | ::boost::parameter::aux::is_optional<T> |
120 | , ::boost::mpl::true_ |
121 | , ::boost::parameter::aux::is_required<T> |
122 | >::type |
123 | , ::boost::parameter::aux::is_deduced0<T> |
124 | , ::boost::mpl::false_ |
125 | >::type |
126 | { |
127 | }; |
128 | #endif // BOOST_PARAMETER_CAN_USE_MP11 |
129 | }}} // namespace boost::parameter::aux |
130 | |
131 | #endif // include guard |
132 | |
133 | |