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
9 template<typename T>
10 using term = boost::yap::terminal<boost::yap::expression, T>;
11
12 template<typename T>
13 using ref = boost::yap::expression_ref<boost::yap::expression, T>;
14
15 namespace yap = boost::yap;
16 namespace bh = boost::hana;
17
18
19 template<yap::expr_kind Kind, typename Tuple>
20 struct expr
21 {
22 static yap::expr_kind const kind = Kind;
23 Tuple elements;
24
25 BOOST_YAP_USER_ASSIGN_OPERATOR(expr, ::expr);
26 };
27
28
29 static_assert(yap::detail::copy_or_move<int, int const &>::value, "");
30 static_assert(yap::detail::copy_or_move<int, int &>::value, "");
31 static_assert(yap::detail::copy_or_move<int, int &&>::value, "");
32 static_assert(!yap::detail::copy_or_move<int, int const &&>::value, "");
33 static_assert(!yap::detail::copy_or_move<int, int>::value, "");
34
35
compile_user_macros()36 void compile_user_macros()
37 {
38 using namespace boost::hana::literals;
39
40 expr<yap::expr_kind::negate, bh::tuple<int>> negation1;
41 negation1.elements[0_c] = 1;
42 expr<yap::expr_kind::negate, bh::tuple<int>> negation2;
43 negation2.elements[0_c] = 2;
44
45 // Normal-rules assignment.
46 negation2 = negation1;
47 assert(negation2.elements[0_c] == 1);
48
49 negation2.elements[0_c] = 2;
50
51 // Normal-rules move assignment.
52 negation2 = std::move(negation1);
53 assert(negation2.elements[0_c] == 1);
54
55 // Produce a new expression via BOOST_YAP_USER_ASSIGN_OPERATOR.
56 auto expr = negation1 = 2;
57 (void)expr;
58 }
59