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
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
|
// Copyright Abel Sinkovics (abel@sinkovics.hu) 2012.
// 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/metaparse/repeated.hpp>
#include <boost/metaparse/sequence.hpp>
#include <boost/metaparse/lit_c.hpp>
#include <boost/metaparse/last_of.hpp>
#include <boost/metaparse/space.hpp>
#include <boost/metaparse/int_.hpp>
#include <boost/metaparse/foldl_reject_incomplete_start_with_parser.hpp>
#include <boost/metaparse/one_of.hpp>
#include <boost/metaparse/get_result.hpp>
#include <boost/metaparse/token.hpp>
#include <boost/metaparse/entire_input.hpp>
#include <boost/metaparse/string.hpp>
#include <boost/metaparse/transform.hpp>
#include <boost/metaparse/always.hpp>
#include <boost/metaparse/build_parser.hpp>
#include <boost/mpl/apply_wrap.hpp>
#include <boost/mpl/front.hpp>
#include <boost/mpl/back.hpp>
#include <boost/mpl/plus.hpp>
#include <boost/mpl/minus.hpp>
#include <boost/mpl/times.hpp>
#include <boost/mpl/divides.hpp>
#include <boost/mpl/bool.hpp>
#include <boost/mpl/equal_to.hpp>
#include <boost/mpl/if.hpp>
using boost::metaparse::sequence;
using boost::metaparse::lit_c;
using boost::metaparse::last_of;
using boost::metaparse::space;
using boost::metaparse::repeated;
using boost::metaparse::build_parser;
using boost::metaparse::int_;
using boost::metaparse::foldl_reject_incomplete_start_with_parser;
using boost::metaparse::get_result;
using boost::metaparse::one_of;
using boost::metaparse::token;
using boost::metaparse::entire_input;
using boost::metaparse::transform;
using boost::metaparse::always;
using boost::mpl::apply_wrap1;
using boost::mpl::front;
using boost::mpl::back;
using boost::mpl::plus;
using boost::mpl::minus;
using boost::mpl::times;
using boost::mpl::divides;
using boost::mpl::if_;
using boost::mpl::bool_;
using boost::mpl::equal_to;
/*
* The grammar
*
* expression ::= plus_exp
* plus_exp ::= prod_exp ((plus_token | minus_token) prod_exp)*
* prod_exp ::= value_exp ((mult_token | div_token) value_exp)*
* value_exp ::= int_token | '_'
*/
typedef token<lit_c<'+'> > plus_token;
typedef token<lit_c<'-'> > minus_token;
typedef token<lit_c<'*'> > mult_token;
typedef token<lit_c<'/'> > div_token;
typedef token<int_> int_token;
typedef token<lit_c<'_'> > arg_token;
template <class T, char C>
struct is_c : bool_<T::type::value == C> {};
struct build_plus
{
template <class A, class B>
struct _plus
{
typedef _plus type;
template <class T>
struct apply :
plus<typename apply_wrap1<A, T>::type, typename apply_wrap1<B, T>::type>
{};
};
template <class A, class B>
struct _minus
{
typedef _minus type;
template <class T>
struct apply :
minus<typename apply_wrap1<A, T>::type, typename apply_wrap1<B, T>::type>
{};
};
template <class State, class C>
struct apply :
if_<
typename is_c<front<C>, '+'>::type,
_plus<State, typename back<C>::type>,
_minus<State, typename back<C>::type>
>
{};
};
struct build_mult
{
template <class A, class B>
struct _mult
{
typedef _mult type;
template <class T>
struct apply :
times<typename apply_wrap1<A, T>::type, typename apply_wrap1<B, T>::type>
{};
};
template <class A, class B>
struct _div
{
typedef _div type;
template <class T>
struct apply :
divides<
typename apply_wrap1<A, T>::type,
typename apply_wrap1<B, T>::type
>
{};
};
template <class State, class C>
struct apply :
if_<
typename is_c<front<C>, '*'>::type,
_mult<State, typename back<C>::type>,
_div<State, typename back<C>::type>
>
{};
};
class build_value
{
private:
template <class V>
struct impl
{
typedef impl type;
template <class T>
struct apply : V {};
};
public:
typedef build_value type;
template <class V>
struct apply : impl<typename V::type> {};
};
struct arg
{
typedef arg type;
template <class T>
struct apply
{
typedef T type;
};
};
typedef
one_of<transform<int_token, build_value>, always<arg_token, arg> >
value_exp;
typedef
foldl_reject_incomplete_start_with_parser<
sequence<one_of<mult_token, div_token>, value_exp>,
value_exp,
build_mult
>
prod_exp;
typedef
foldl_reject_incomplete_start_with_parser<
sequence<one_of<plus_token, minus_token>, prod_exp>,
prod_exp,
build_plus
>
plus_exp;
typedef last_of<repeated<space>, plus_exp> expression;
typedef build_parser<entire_input<expression> > metafunction_parser;
#if BOOST_METAPARSE_STD < 2011
template <class Exp>
struct meta_lambda : apply_wrap1<metafunction_parser, Exp> {};
int main()
{
using std::cout;
using std::endl;
using boost::metaparse::string;
typedef meta_lambda<string<'1','3'> >::type metafunction_class_1;
typedef meta_lambda<string<'2',' ','+',' ','3'> >::type metafunction_class_2;
typedef meta_lambda<string<'2',' ','*',' ','2'> >::type metafunction_class_3;
typedef
meta_lambda<string<' ','1','+',' ','2','*','4','-','6','/','2'> >::type
metafunction_class_4;
typedef meta_lambda<string<'2',' ','*',' ','_'> >::type metafunction_class_5;
typedef boost::mpl::int_<11> int11;
cout
<< apply_wrap1<metafunction_class_1, int11>::type::value << endl
<< apply_wrap1<metafunction_class_2, int11>::type::value << endl
<< apply_wrap1<metafunction_class_3, int11>::type::value << endl
<< apply_wrap1<metafunction_class_4, int11>::type::value << endl
<< apply_wrap1<metafunction_class_5, int11>::type::value << endl
;
}
#else
#ifdef META_LAMBDA
#error META_LAMBDA already defined
#endif
#define META_LAMBDA(exp) \
apply_wrap1<metafunction_parser, BOOST_METAPARSE_STRING(#exp)>::type
int main()
{
using std::cout;
using std::endl;
typedef META_LAMBDA(13) metafunction_class_1;
typedef META_LAMBDA(2 + 3) metafunction_class_2;
typedef META_LAMBDA(2 * 2) metafunction_class_3;
typedef META_LAMBDA( 1+ 2*4-6/2) metafunction_class_4;
typedef META_LAMBDA(2 * _) metafunction_class_5;
typedef boost::mpl::int_<11> int11;
cout
<< apply_wrap1<metafunction_class_1, int11>::type::value << endl
<< apply_wrap1<metafunction_class_2, int11>::type::value << endl
<< apply_wrap1<metafunction_class_3, int11>::type::value << endl
<< apply_wrap1<metafunction_class_4, int11>::type::value << endl
<< apply_wrap1<metafunction_class_5, int11>::type::value << endl
;
}
#endif
|
