ceph/src/boost/libs/hana/test/_include/laws/monoid.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_MONOID_HPP
   6 #define BOOST_HANA_TEST_LAWS_MONOID_HPP
   7
   8 #include <boost/hana/assert.hpp>
   9 #include <boost/hana/bool.hpp>
  10 #include <boost/hana/concept/comparable.hpp>
  11 #include <boost/hana/core/when.hpp>
  12 #include <boost/hana/functional/capture.hpp>
  13 #include <boost/hana/lazy.hpp>
  14 #include <boost/hana/concept/monoid.hpp>
  15
  16 #include <laws/base.hpp>
  17
  18
  19 namespace boost { namespace hana { namespace test {
  20     template <typename M, typename = when<true>>
  21     struct TestMonoid : TestMonoid<M, laws> {
  22         using TestMonoid<M, laws>::TestMonoid;
  23     };
  24
  25     template <typename M>
  26     struct TestMonoid<M, laws> {
  27         template <typename Xs>
  28         TestMonoid(Xs xs) {
  29 #ifdef BOOST_HANA_WORKAROUND_MSVC_DECLTYPEAUTO_RETURNTYPE_662735
  30             zero<M>(); // force adding zero<M>'s member function to pending temploid list
  31 #endif
  32
  33             hana::for_each(xs, hana::capture(xs)([](auto xs, auto a) {
  34                 static_assert(Monoid<decltype(a)>{}, "");
  35
  36                 // left identity
  37                 BOOST_HANA_CHECK(hana::equal(
  38                     hana::plus(zero<M>(), a),
  39                     a
  40                 ));
  41
  42                 // right identity
  43                 BOOST_HANA_CHECK(hana::equal(
  44                     hana::plus(a, zero<M>()),
  45                     a
  46                 ));
  47
  48                 hana::for_each(xs,
  49                 hana::capture(xs, a)([](auto xs, auto a, auto b) {
  50                     hana::for_each(xs,
  51                     hana::capture(a, b)([](auto a, auto b, auto c) {
  52                         // associativity
  53                         BOOST_HANA_CHECK(equal(
  54                             hana::plus(a, hana::plus(b, c)),
  55                             hana::plus(hana::plus(a, b), c)
  56                         ));
  57                     }));
  58                 }));
  59
  60             }));
  61         }
  62     };
  63
  64     template <typename C>
  65     struct TestMonoid<C, when<Constant<C>::value>>
  66         : TestMonoid<C, laws>
  67     {
  68         template <typename Xs>
  69         TestMonoid(Xs xs) : TestMonoid<C, laws>{xs} {
  70
  71             BOOST_HANA_CHECK(hana::equal(
  72                 hana::value(zero<C>()),
  73                 zero<typename C::value_type>()
  74             ));
  75
  76             foreach2(xs, [](auto x, auto y) {
  77                 BOOST_HANA_CHECK(hana::equal(
  78                     hana::plus(hana::value(x), hana::value(y)),
  79                     hana::value(hana::plus(x, y))
  80                 ));
  81             });
  82         }
  83     };
  84 }}} // end namespace boost::hana::test
  85
  86 #endif // !BOOST_HANA_TEST_LAWS_MONOID_HPP