1 // Copyright (C) 2016-2018 T. Zachary Laine
2 //
3 // Distributed under the Boost Software License, Version 1.0. (See
4 // accompanying file LICENSE_1_0.txt or copy at
5 // http://www.boost.org/LICENSE_1_0.txt)
6 #include <boost/yap/expression.hpp>
7
8 #include <boost/mpl/assert.hpp>
9
10 #include <boost/test/minimal.hpp>
11
12
13 template<typename T>
14 using term = boost::yap::terminal<boost::yap::expression, T>;
15
16 namespace yap = boost::yap;
17
18 namespace reference_returning {
19
20 struct number
21 {
22 double value;
23 };
24
25 number a_result{3.0};
26 number const the_result{13.0};
27
operator +(number a,number b)28 number const & operator+(number a, number b) { return the_result; }
29
operator -(number a,number b)30 number & operator-(number a, number b) { return a_result; }
31 }
32
test_main(int,char * [])33 int test_main(int, char * [])
34 {
35 {
36 term<reference_returning::number> unity = {{1.0}};
37 auto plus_expr = unity + reference_returning::number{1.0};
38
39 {
40 reference_returning::number const & n = evaluate(plus_expr);
41 BOOST_CHECK(&n == &reference_returning::the_result);
42 }
43
44 using plus_eval_type = decltype(evaluate(plus_expr));
45 BOOST_MPL_ASSERT((std::is_same<
46 plus_eval_type,
47 reference_returning::number const &>));
48
49 auto minus_expr = unity - reference_returning::number{1.0};
50
51 {
52 reference_returning::number & n = evaluate(minus_expr);
53 BOOST_CHECK(&n == &reference_returning::a_result);
54 }
55
56 using minus_eval_type = decltype(evaluate(minus_expr));
57 BOOST_MPL_ASSERT((std::is_same<
58 minus_eval_type,
59 reference_returning::number &>));
60
61 using namespace yap::literals;
62
63 {
64 reference_returning::number & n =
65 evaluate(1_p, reference_returning::a_result);
66 BOOST_CHECK(&n == &reference_returning::a_result);
67 }
68
69 using a_eval_type = decltype(evaluate(1_p, reference_returning::a_result));
70 BOOST_MPL_ASSERT(
71 (std::is_same<
72 a_eval_type,
73 reference_returning::number &>));
74
75 {
76 reference_returning::number const & n =
77 evaluate(1_p, reference_returning::the_result);
78 BOOST_CHECK(&n == &reference_returning::the_result);
79 }
80
81 using the_eval_type = decltype(evaluate(1_p, reference_returning::the_result));
82 BOOST_MPL_ASSERT(
83 (std::is_same<
84 the_eval_type,
85 reference_returning::number const &>));
86 }
87
88 return 0;
89 }
90