libs/hana/test/_include/laws/hashable.hpp

   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 #ifndef BOOST_HANA_TEST_LAWS_HASHABLE_HPP
   6 #define BOOST_HANA_TEST_LAWS_HASHABLE_HPP
   7
   8 #include <boost/hana/assert.hpp>
   9 #include <boost/hana/bool.hpp>
  10 #include <boost/hana/concept/hashable.hpp>
  11 #include <boost/hana/core/default.hpp>
  12 #include <boost/hana/core/tag_of.hpp>
  13 #include <boost/hana/core/when.hpp>
  14 #include <boost/hana/equal.hpp>
  15 #include <boost/hana/for_each.hpp>
  16 #include <boost/hana/hash.hpp>
  17 #include <boost/hana/if.hpp>
  18
  19 #include <laws/base.hpp>
  20
  21
  22 namespace boost { namespace hana { namespace test {
  23     template <typename G, typename = when<true>>
  24     struct TestHashable : TestHashable<G, laws> {
  25         using TestHashable<G, laws>::TestHashable;
  26     };
  27
  28     template <typename H>
  29     struct TestHashable<H, laws> {
  30         template <typename Xs>
  31         TestHashable(Xs xs) {
  32             hana::for_each(xs, [](auto x) {
  33                 static_assert(Hashable<decltype(x)>{}, "");
  34             });
  35
  36             hana::for_each(xs, [&](auto const& x) {
  37                 hana::for_each(xs, [&](auto const& y) {
  38                     using X = hana::tag_of_t<decltype(x)>;
  39                     using Y = hana::tag_of_t<decltype(y)>;
  40                     constexpr bool comparable = !hana::is_default<
  41                         hana::equal_impl<X, Y>
  42                     >::value;
  43
  44                     hana::if_(hana::bool_c<comparable>,
  45                         [](auto const& x, auto const& y) {
  46                             BOOST_HANA_CHECK(
  47                                 hana::equal(x, y)
  48                                     ^implies^
  49                                 hana::equal(hana::hash(x), hana::hash(y))
  50                             );
  51                         },
  52                         [](auto...) { }
  53                     )(x, y);
  54                 });
  55             });
  56         }
  57     };
  58 }}} // end namespace boost::hana::test
  59
  60 #endif // !BOOST_HANA_TEST_LAWS_HASHABLE_HPP