1 // Copyright Louis Dionne 2013-2017
2 // Distributed under the Boost Software License, Version 1.0.
3 // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
4
5 #include <boost/hana/assert.hpp>
6 #include <boost/hana/concept/metafunction.hpp>
7 #include <boost/hana/equal.hpp>
8 #include <boost/hana/not.hpp>
9 #include <boost/hana/type.hpp>
10
11 #include <type_traits>
12 namespace hana = boost::hana;
13
14
15 struct x1; struct x2; struct x3;
16 struct y1 { }; struct y2 { }; struct y3 { };
17
18 template <typename ...> struct mf { struct type { }; };
19 struct mfc { template <typename ...> struct apply { struct type { }; }; };
20 template <typename ...> struct tpl { };
21
22 // make sure `integral(f)(...)` returns the right type
23 static_assert(std::is_same<
24 decltype(hana::integral(hana::metafunction<mf>)()),
25 mf<>::type
26 >{}, "");
27 static_assert(std::is_same<
28 decltype(hana::integral(hana::metafunction<mf>)(hana::type_c<x1>)),
29 mf<x1>::type
30 >{}, "");
31 static_assert(std::is_same<
32 decltype(hana::integral(hana::metafunction<mf>)(hana::type_c<x1>, hana::type_c<x2>)),
33 mf<x1, x2>::type
34 >{}, "");
35
36 static_assert(std::is_same<
37 decltype(hana::integral(hana::template_<tpl>)()),
38 tpl<>
39 >{}, "");
40 static_assert(std::is_same<
41 decltype(hana::integral(hana::template_<tpl>)(hana::type_c<x1>)),
42 tpl<x1>
43 >{}, "");
44 static_assert(std::is_same<
45 decltype(hana::integral(hana::template_<tpl>)(hana::type_c<x1>, hana::type_c<x2>)),
46 tpl<x1, x2>
47 >{}, "");
48
49 static_assert(std::is_same<
50 decltype(hana::integral(hana::metafunction_class<mfc>)()),
51 mfc::apply<>::type
52 >{}, "");
53 static_assert(std::is_same<
54 decltype(hana::integral(hana::metafunction_class<mfc>)(hana::type_c<x1>)),
55 mfc::apply<x1>::type
56 >{}, "");
57 static_assert(std::is_same<
58 decltype(hana::integral(hana::metafunction_class<mfc>)(hana::type_c<x1>, hana::type_c<x2>)),
59 mfc::apply<x1, x2>::type
60 >{}, "");
61
62 // Make sure integral is SFINAE-friendly
63 struct invalid_hana_metafunction {
64 template <typename ...> struct apply { /* missing type alias */ };
65 };
66 auto invalid_integral = hana::integral(invalid_hana_metafunction{});
67 BOOST_HANA_CONSTANT_CHECK(hana::not_(
68 hana::is_valid(invalid_integral)(hana::type_c<void>, hana::type_c<void>)
69 ));
70
71
main()72 int main() {
73 // Make sure we can perform the call; we already made sure the return type was correct
74 constexpr auto a = hana::integral(hana::metafunction<mf>)(); (void)a;
75 constexpr auto b = hana::integral(hana::metafunction<mf>)(hana::type_c<x1>); (void)b;
76 constexpr auto c = hana::integral(hana::metafunction<mf>)(hana::type_c<x1>, hana::type_c<x2>); (void)c;
77 constexpr auto d = hana::integral(hana::metafunction<mf>)(hana::type_c<x1>, hana::type_c<x2>, hana::type_c<x3>); (void)d;
78
79 // Make sure we don't read from a non-constexpr variable
80 auto t = hana::type_c<x1>;
81 constexpr auto r = hana::integral(hana::metafunction<mf>)(t);
82 (void)r;
83 }
84