1// Copyright Louis Dionne 2013-2022
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/comparable.hpp>
7#include <boost/hana/equal.hpp>
8#include <boost/hana/not.hpp>
9#include <boost/hana/tuple.hpp>
10
11#include <laws/base.hpp>
12#include <laws/comparable.hpp>
13
14#include <type_traits>
15namespace hana = boost::hana;
16
17
18// Minimal EqualityComparable types
19struct eq1 { int value; };
20struct eq2 {
21 int value;
22 constexpr operator eq1() const { return {.value: value}; }
23};
24
25template <typename T, typename U, typename = std::enable_if_t<
26 (std::is_same<T, eq1>{} || std::is_same<T, eq2>{}) &&
27 (std::is_same<U, eq1>{} || std::is_same<U, eq2>{})
28>>
29constexpr bool operator==(T a, U b)
30{ return a.value == b.value; }
31
32template <typename T, typename U, typename = std::enable_if_t<
33 (std::is_same<T, eq1>{} || std::is_same<T, eq2>{}) &&
34 (std::is_same<U, eq1>{} || std::is_same<U, eq2>{})
35>>
36constexpr bool operator!=(T a, U b)
37{ return !(a == b); }
38
39
40int main() {
41 // equal
42 {
43 // Two objects of different data types are unequal by default,
44 // and no model is provided for two objects of the same data type.
45 struct Random1 { }; struct Random2 { };
46 BOOST_HANA_CONSTANT_CHECK(hana::not_(hana::equal(Random1{}, Random2{})));
47 static_assert(!hana::Comparable<Random1>::value, "");
48 static_assert(!hana::Comparable<Random2>::value, "");
49
50 // Provided model for EqualityComparable types
51 BOOST_HANA_CONSTEXPR_CHECK(hana::equal(eq1{0}, eq1{0}));
52 BOOST_HANA_CONSTEXPR_CHECK(hana::not_(hana::equal(eq1{0}, eq1{1})));
53 BOOST_HANA_CONSTEXPR_CHECK(hana::not_(hana::equal(eq1{1}, eq1{0})));
54
55 BOOST_HANA_CONSTEXPR_CHECK(hana::equal(eq1{0}, eq2{0}));
56 BOOST_HANA_CONSTEXPR_CHECK(hana::not_(hana::equal(eq1{0}, eq2{1})));
57 BOOST_HANA_CONSTEXPR_CHECK(hana::not_(hana::equal(eq1{1}, eq2{0})));
58
59 BOOST_HANA_CONSTEXPR_CHECK(hana::equal(eq2{0}, eq1{0}));
60 BOOST_HANA_CONSTEXPR_CHECK(hana::not_(hana::equal(eq2{0}, eq1{1})));
61 BOOST_HANA_CONSTEXPR_CHECK(hana::not_(hana::equal(eq2{1}, eq1{0})));
62 }
63
64 // laws
65 hana::test::TestComparable<int>{hana::make_tuple(0,1,2,3,4,5)};
66 hana::test::TestComparable<unsigned int>{hana::make_tuple(0u,1u,2u,3u,4u,5u)};
67 hana::test::TestComparable<long>{hana::make_tuple(0l,1l,2l,3l,4l,5l)};
68 hana::test::TestComparable<unsigned long>{hana::make_tuple(0ul,1ul,2ul,3ul,4ul,5ul)};
69 hana::test::TestComparable<eq1>{hana::make_tuple(eq1{0}, eq1{1}, eq1{2}, eq1{3}, eq1{4})};
70}
71

source code of boost/libs/hana/test/comparable.cpp