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/type.hpp>
   9
  10 #include <type_traits>
  11 namespace hana = boost::hana;
  12
  13
  14 struct x1; struct x2; struct x3;
  15 struct y1 { }; struct y2 { }; struct y3 { };
  16
  17 template <typename ...> struct mf { struct type { }; };
  18 struct mfc { template <typename ...> struct apply { struct type { }; }; };
  19 template <typename ...> struct tpl { };
  20
  21 // make sure `integral(f)(...)` returns the right type
  22 static_assert(std::is_same<
  23     decltype(hana::integral(hana::metafunction<mf>)()),
  24     mf<>::type
  25 >{}, "");
  26 static_assert(std::is_same<
  27     decltype(hana::integral(hana::metafunction<mf>)(hana::type_c<x1>)),
  28     mf<x1>::type
  29 >{}, "");
  30 static_assert(std::is_same<
  31     decltype(hana::integral(hana::metafunction<mf>)(hana::type_c<x1>, hana::type_c<x2>)),
  32     mf<x1, x2>::type
  33 >{}, "");
  34
  35 static_assert(std::is_same<
  36     decltype(hana::integral(hana::template_<tpl>)()),
  37     tpl<>
  38 >{}, "");
  39 static_assert(std::is_same<
  40     decltype(hana::integral(hana::template_<tpl>)(hana::type_c<x1>)),
  41     tpl<x1>
  42 >{}, "");
  43 static_assert(std::is_same<
  44     decltype(hana::integral(hana::template_<tpl>)(hana::type_c<x1>, hana::type_c<x2>)),
  45     tpl<x1, x2>
  46 >{}, "");
  47
  48 static_assert(std::is_same<
  49     decltype(hana::integral(hana::metafunction_class<mfc>)()),
  50     mfc::apply<>::type
  51 >{}, "");
  52 static_assert(std::is_same<
  53     decltype(hana::integral(hana::metafunction_class<mfc>)(hana::type_c<x1>)),
  54     mfc::apply<x1>::type
  55 >{}, "");
  56 static_assert(std::is_same<
  57     decltype(hana::integral(hana::metafunction_class<mfc>)(hana::type_c<x1>, hana::type_c<x2>)),
  58     mfc::apply<x1, x2>::type
  59 >{}, "");
  60
  61
  62 int main() {
  63     // Make sure we can perform the call; we already made sure the return type was correct
  64     constexpr auto a = hana::integral(hana::metafunction<mf>)(); (void)a;
  65     constexpr auto b = hana::integral(hana::metafunction<mf>)(hana::type_c<x1>); (void)b;
  66     constexpr auto c = hana::integral(hana::metafunction<mf>)(hana::type_c<x1>, hana::type_c<x2>); (void)c;
  67     constexpr auto d = hana::integral(hana::metafunction<mf>)(hana::type_c<x1>, hana::type_c<x2>, hana::type_c<x3>); (void)d;
  68
  69     // Make sure we don't read from a non-constexpr variable
  70     auto t = hana::type_c<x1>;
  71     constexpr auto r = hana::integral(hana::metafunction<mf>)(t);
  72     (void)r;
  73 }