ceph/src/boost/libs/hana/test/type/integral.cpp

   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
  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 }