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/tuple.hpp>
7
8#include <string>
9namespace hana = boost::hana;
10
11
12struct Empty {};
13
14struct S {
15 constexpr S()
16 : a{1, Empty{}},
17 k(hana::at_c<0>(xs&: a)),
18 e(hana::at_c<1>(xs&: a))
19 { }
20
21 hana::tuple<int, Empty> a;
22 int k;
23 Empty e;
24};
25
26constexpr hana::tuple<int, int> getP () { return { 3, 4 }; }
27
28int main() {
29 {
30 using T = hana::tuple<int>;
31 T t(3);
32 BOOST_HANA_RUNTIME_CHECK(hana::at_c<0>(t) == 3);
33 hana::at_c<0>(xs&: t) = 2;
34 BOOST_HANA_RUNTIME_CHECK(hana::at_c<0>(t) == 2);
35 }
36 {
37 using T = hana::tuple<std::string, int>;
38 T t("high", 5);
39 BOOST_HANA_RUNTIME_CHECK(hana::at_c<0>(t) == "high");
40 BOOST_HANA_RUNTIME_CHECK(hana::at_c<1>(t) == 5);
41 hana::at_c<0>(xs&: t) = "four";
42 hana::at_c<1>(xs&: t) = 4;
43 BOOST_HANA_RUNTIME_CHECK(hana::at_c<0>(t) == "four");
44 BOOST_HANA_RUNTIME_CHECK(hana::at_c<1>(t) == 4);
45 }
46 {
47 using T = hana::tuple<double&, std::string, int>;
48 double d = 1.5;
49 T t(d, "high", 5);
50 BOOST_HANA_RUNTIME_CHECK(hana::at_c<0>(t) == 1.5);
51 BOOST_HANA_RUNTIME_CHECK(hana::at_c<1>(t) == "high");
52 BOOST_HANA_RUNTIME_CHECK(hana::at_c<2>(t) == 5);
53 hana::at_c<0>(xs&: t) = 2.5;
54 hana::at_c<1>(xs&: t) = "four";
55 hana::at_c<2>(xs&: t) = 4;
56 BOOST_HANA_RUNTIME_CHECK(hana::at_c<0>(t) == 2.5);
57 BOOST_HANA_RUNTIME_CHECK(hana::at_c<1>(t) == "four");
58 BOOST_HANA_RUNTIME_CHECK(hana::at_c<2>(t) == 4);
59 BOOST_HANA_RUNTIME_CHECK(d == 2.5);
60 }
61 // get on a rvalue tuple
62 {
63 static_assert(hana::at_c<0>(xs: hana::tuple<float, int, double, long>{0.0f, 1, 2.0, 3L}) == 0, "" );
64 static_assert(hana::at_c<1>(xs: hana::tuple<float, int, double, long>{0.0f, 1, 2.0, 3L}) == 1, "" );
65 static_assert(hana::at_c<2>(xs: hana::tuple<float, int, double, long>{0.0f, 1, 2.0, 3L}) == 2, "" );
66 static_assert(hana::at_c<3>(xs: hana::tuple<float, int, double, long>{0.0f, 1, 2.0, 3L}) == 3, "" );
67 static_assert(S().k == 1, "");
68 static_assert(hana::at_c<1>(xs: getP()) == 4, "");
69 }
70 {
71 // make sure get<> returns the right types
72 struct T { };
73 struct U { };
74 struct V { };
75
76 hana::tuple<T, U, V> xs{};
77 (void)static_cast<T>(hana::at_c<0>(xs));
78 (void)static_cast<U>(hana::at_c<1>(xs));
79 (void)static_cast<V>(hana::at_c<2>(xs));
80 }
81}
82

source code of boost/libs/hana/test/tuple/at.non_const.cpp