73ef4ff3
 Hu Chunming
提交三方库
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
|
/*==============================================================================
Copyright (c) 2005-2010 Joel de Guzman
Copyright (c) 2010 Thomas Heller
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
==============================================================================*/
#include <boost/phoenix/phoenix.hpp>
#include <boost/proto/proto.hpp>
#include <boost/proto/debug.hpp>
namespace phoenix = boost::phoenix;
namespace proto = boost::proto;
using phoenix::evaluator;
#ifdef _MSC_VER
// redifining evaluator, this is because MSVC chokes on function types like:
// F(G(...))
#define evaluator(A0, A1) proto::call<phoenix::evaluator(A0, A1)>
#endif
struct invert_actions
{
template <typename Rule>
struct when
: proto::nary_expr<
proto::_
, proto::vararg<
proto::when<proto::_, evaluator(proto::_, phoenix::_context)>
>
>
{};
};
template <>
struct invert_actions::when<phoenix::rule::plus>
: proto::call<
phoenix::functional::make_minus(
evaluator(proto::_left, phoenix::_context)
, evaluator(proto::_right, phoenix::_context)
)
>
{};
template <>
struct invert_actions::when<phoenix::rule::minus>
: proto::call<
phoenix::functional::make_plus(
evaluator(proto::_left, phoenix::_context)
, evaluator(proto::_right, phoenix::_context)
)
>
{};
template <>
struct invert_actions::when<phoenix::rule::multiplies>
: proto::call<
phoenix::functional::make_divides(
evaluator(proto::_left, phoenix::_context)
, evaluator(proto::_right, phoenix::_context)
)
>
{};
template <>
struct invert_actions::when<phoenix::rule::divides>
: proto::call<
phoenix::functional::make_multiplies(
evaluator(proto::_left, phoenix::_context)
, evaluator(proto::_right, phoenix::_context)
)
>
{};
#ifdef _MSC_VER
#undef evaluator
#endif
template <typename Expr>
void print_expr(Expr const & expr)
{
std::cout << "before inversion:\n";
proto::display_expr(expr);
std::cout << "after inversion:\n";
proto::display_expr(
phoenix::eval(
expr
, phoenix::context(
phoenix::nothing
, invert_actions()
)
)
);
std::cout << "\n";
}
template <typename Expr>
typename
boost::phoenix::result_of::eval<
Expr const&
, phoenix::result_of::make_context<
phoenix::result_of::make_env<>::type
, invert_actions
>::type
>::type
invert(Expr const & expr)
{
return
phoenix::eval(
expr
, phoenix::make_context(
phoenix::make_env()
, invert_actions()
)
);
}
int main()
{
using phoenix::placeholders::_1;
using phoenix::placeholders::_2;
using phoenix::placeholders::_3;
using phoenix::placeholders::_4;
print_expr(_1);
print_expr(_1 + _2);
print_expr(_1 + _2 - _3);
print_expr(_1 * _2);
print_expr(_1 * _2 / _3);
print_expr(_1 * _2 + _3);
print_expr(_1 * _2 - _3);
print_expr(if_(_1 * _4)[_2 - _3]);
print_expr(_1 * invert(_2 - _3));
}
|
