1 | // Copyright David Abrahams 2005. |
2 | // Copyright Cromwell D. Enage 2017. |
3 | // Distributed under the Boost Software License, Version 1.0. |
4 | // (See accompanying file LICENSE_1_0.txt or copy at |
5 | // http://www.boost.org/LICENSE_1_0.txt) |
6 | |
7 | #ifndef BOOST_PARAMETER_AUX_TAG_DWA2005610_HPP |
8 | #define BOOST_PARAMETER_AUX_TAG_DWA2005610_HPP |
9 | |
10 | #include <boost/parameter/aux_/unwrap_cv_reference.hpp> |
11 | #include <boost/parameter/aux_/tagged_argument.hpp> |
12 | #include <boost/parameter/config.hpp> |
13 | |
14 | #if defined(BOOST_PARAMETER_CAN_USE_MP11) && \ |
15 | !BOOST_WORKAROUND(BOOST_MSVC, >= 1910) |
16 | // MSVC-14.1+ assigns rvalue references to tagged_argument instances |
17 | // instead of tagged_argument_rref instances with this code. |
18 | #include <boost/mp11/integral.hpp> |
19 | #include <boost/mp11/utility.hpp> |
20 | #include <type_traits> |
21 | |
22 | namespace boost { namespace parameter { namespace aux { |
23 | |
24 | template <typename Keyword, typename Arg> |
25 | struct tag_if_lvalue_reference |
26 | { |
27 | using type = ::boost::parameter::aux::tagged_argument_list_of_1< |
28 | ::boost::parameter::aux::tagged_argument< |
29 | Keyword |
30 | , typename ::boost::parameter::aux |
31 | ::unwrap_cv_reference<Arg>::type |
32 | > |
33 | >; |
34 | }; |
35 | |
36 | template <typename Keyword, typename Arg> |
37 | struct tag_if_scalar |
38 | { |
39 | using type = ::boost::parameter::aux::tagged_argument_list_of_1< |
40 | ::boost::parameter::aux |
41 | ::tagged_argument<Keyword,typename ::std::add_const<Arg>::type> |
42 | >; |
43 | }; |
44 | |
45 | template <typename Keyword, typename Arg> |
46 | using tag_if_otherwise = ::boost::mp11::mp_if< |
47 | ::std::is_scalar<typename ::std::remove_const<Arg>::type> |
48 | , ::boost::parameter::aux::tag_if_scalar<Keyword,Arg> |
49 | , ::boost::mp11::mp_identity< |
50 | ::boost::parameter::aux::tagged_argument_list_of_1< |
51 | ::boost::parameter::aux::tagged_argument_rref<Keyword,Arg> |
52 | > |
53 | > |
54 | >; |
55 | |
56 | template <typename Keyword, typename Arg> |
57 | using tag = ::boost::mp11::mp_if< |
58 | ::boost::mp11::mp_if< |
59 | ::std::is_lvalue_reference<Arg> |
60 | , ::boost::mp11::mp_true |
61 | , ::boost::parameter::aux::is_cv_reference_wrapper<Arg> |
62 | > |
63 | , ::boost::parameter::aux::tag_if_lvalue_reference<Keyword,Arg> |
64 | , ::boost::parameter::aux::tag_if_otherwise<Keyword,Arg> |
65 | >; |
66 | }}} // namespace boost::parameter::aux_ |
67 | |
68 | #elif defined(BOOST_PARAMETER_HAS_PERFECT_FORWARDING) |
69 | #include <boost/mpl/bool.hpp> |
70 | #include <boost/mpl/if.hpp> |
71 | #include <boost/mpl/eval_if.hpp> |
72 | #include <boost/mpl/identity.hpp> |
73 | #include <boost/type_traits/add_const.hpp> |
74 | #include <boost/type_traits/is_scalar.hpp> |
75 | #include <boost/type_traits/is_lvalue_reference.hpp> |
76 | #include <boost/type_traits/remove_const.hpp> |
77 | |
78 | namespace boost { namespace parameter { namespace aux { |
79 | |
80 | template <typename Keyword, typename ActualArg> |
81 | struct tag |
82 | { |
83 | typedef typename ::boost::parameter::aux |
84 | ::unwrap_cv_reference<ActualArg>::type Arg; |
85 | typedef typename ::boost::add_const<Arg>::type ConstArg; |
86 | typedef typename ::boost::remove_const<Arg>::type MutArg; |
87 | typedef typename ::boost::mpl::eval_if< |
88 | typename ::boost::mpl::if_< |
89 | ::boost::is_lvalue_reference<ActualArg> |
90 | , ::boost::mpl::true_ |
91 | , ::boost::parameter::aux::is_cv_reference_wrapper<ActualArg> |
92 | >::type |
93 | , ::boost::mpl::identity< |
94 | #if defined(BOOST_PARAMETER_CAN_USE_MP11) |
95 | ::boost::parameter::aux::tagged_argument_list_of_1< |
96 | #endif |
97 | ::boost::parameter::aux::tagged_argument<Keyword,Arg> |
98 | #if defined(BOOST_PARAMETER_CAN_USE_MP11) |
99 | > |
100 | #endif |
101 | > |
102 | , ::boost::mpl::if_< |
103 | ::boost::is_scalar<MutArg> |
104 | #if defined(BOOST_PARAMETER_CAN_USE_MP11) |
105 | , ::boost::parameter::aux::tagged_argument_list_of_1< |
106 | ::boost::parameter::aux::tagged_argument<Keyword,ConstArg> |
107 | > |
108 | , ::boost::parameter::aux::tagged_argument_list_of_1< |
109 | ::boost::parameter::aux::tagged_argument_rref<Keyword,Arg> |
110 | > |
111 | #else |
112 | , ::boost::parameter::aux::tagged_argument<Keyword,ConstArg> |
113 | , ::boost::parameter::aux::tagged_argument_rref<Keyword,Arg> |
114 | #endif |
115 | > |
116 | >::type type; |
117 | }; |
118 | }}} // namespace boost::parameter::aux_ |
119 | |
120 | #else // !defined(BOOST_PARAMETER_HAS_PERFECT_FORWARDING) |
121 | |
122 | namespace boost { namespace parameter { namespace aux { |
123 | |
124 | template < |
125 | typename Keyword |
126 | , typename Arg |
127 | #if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564)) |
128 | , typename = typename ::boost::parameter::aux |
129 | ::is_cv_reference_wrapper<Arg>::type |
130 | #endif |
131 | > |
132 | struct tag |
133 | { |
134 | typedef ::boost::parameter::aux::tagged_argument< |
135 | Keyword |
136 | , typename ::boost::parameter::aux::unwrap_cv_reference<Arg>::type |
137 | > type; |
138 | }; |
139 | }}} // namespace boost::parameter::aux_ |
140 | |
141 | #if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564)) |
142 | #include <boost/mpl/bool.hpp> |
143 | #include <boost/type_traits/remove_reference.hpp> |
144 | |
145 | namespace boost { namespace parameter { namespace aux { |
146 | |
147 | template <typename Keyword, typename Arg> |
148 | struct tag<Keyword,Arg,::boost::mpl::false_> |
149 | { |
150 | typedef ::boost::parameter::aux::tagged_argument< |
151 | Keyword |
152 | , typename ::boost::remove_reference<Arg>::type |
153 | > type; |
154 | }; |
155 | }}} // namespace boost::parameter::aux_ |
156 | |
157 | #endif // Borland workarounds needed. |
158 | #endif // MP11 or perfect forwarding support |
159 | #endif // include guard |
160 | |
161 | |