1
2 // Copyright 2015-2017 Peter Dimov.
3 //
4 // Distributed under the Boost Software License, Version 1.0.
5 //
6 // See accompanying file LICENSE_1_0.txt or copy at
7 // http://www.boost.org/LICENSE_1_0.txt
8
9
10 #include <boost/mp11/utility.hpp>
11 #include <boost/mp11/integral.hpp>
12 #include <boost/mp11/detail/config.hpp>
13 #include <boost/core/lightweight_test_trait.hpp>
14 #include <type_traits>
15
16 using boost::mp11::mp_identity;
17 using boost::mp11::mp_true;
18 using boost::mp11::mp_false;
19
20 template<class T> struct has_type
21 {
22 template<class U> static mp_true f( mp_identity<typename U::type>* );
23 template<class U> static mp_false f( ... );
24
25 using type = decltype( f<T>(0) );
26
27 static const bool value = type::value;
28 };
29
30 using boost::mp11::mp_defer;
31
32 template<class T> using add_pointer = T*;
33 template<class... T> using add_pointer_impl = mp_defer<add_pointer, T...>;
34
35 using boost::mp11::mp_quote;
36
37 using Q_add_pointer = mp_quote<add_pointer>;
38 template<class... T> using Q_add_pointer_impl = mp_defer<Q_add_pointer::fn, T...>;
39
main()40 int main()
41 {
42 BOOST_TEST_TRAIT_TRUE((has_type<add_pointer_impl<void>>));
43 BOOST_TEST_TRAIT_TRUE((std::is_same<add_pointer_impl<void>::type, void*>));
44
45 BOOST_TEST_TRAIT_TRUE((has_type<add_pointer_impl<int>>));
46 BOOST_TEST_TRAIT_TRUE((std::is_same<add_pointer_impl<int>::type, int*>));
47
48 BOOST_TEST_TRAIT_FALSE((has_type<add_pointer_impl<>>));
49 BOOST_TEST_TRAIT_FALSE((has_type<add_pointer_impl<void, void>>));
50
51 #if !BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, <= 1800 )
52 BOOST_TEST_TRAIT_TRUE((has_type<Q_add_pointer_impl<void>>));
53 #endif
54 BOOST_TEST_TRAIT_TRUE((std::is_same<Q_add_pointer_impl<void>::type, void*>));
55
56 #if !BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, <= 1800 )
57 BOOST_TEST_TRAIT_TRUE((has_type<Q_add_pointer_impl<int>>));
58 #endif
59 BOOST_TEST_TRAIT_TRUE((std::is_same<Q_add_pointer_impl<int>::type, int*>));
60
61 BOOST_TEST_TRAIT_FALSE((has_type<Q_add_pointer_impl<>>));
62 BOOST_TEST_TRAIT_FALSE((has_type<Q_add_pointer_impl<void, void>>));
63
64 return boost::report_errors();
65 }
66