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1 | // Copyright Abel Sinkovics (abel@sinkovics.hu) 2011. |
2 | // Distributed under the Boost Software License, Version 1.0. | |
3 | // (See accompanying file LICENSE_1_0.txt or copy at | |
4 | // http://www.boost.org/LICENSE_1_0.txt) | |
5 | ||
6 | #include <boost/metaparse/foldl1.hpp> | |
7 | #include <boost/metaparse/build_parser.hpp> | |
8 | #include <boost/metaparse/transform.hpp> | |
9 | #include <boost/metaparse/one_of_c.hpp> | |
10 | #include <boost/metaparse/entire_input.hpp> | |
11 | #include <boost/metaparse/string.hpp> | |
12 | ||
13 | #include <boost/metaparse/util/digit_to_int.hpp> | |
14 | ||
15 | #include <boost/mpl/int.hpp> | |
16 | #include <boost/mpl/plus.hpp> | |
17 | #include <boost/mpl/times.hpp> | |
18 | ||
19 | #include <iostream> | |
20 | ||
21 | using boost::metaparse::foldl1; | |
22 | using boost::metaparse::build_parser; | |
23 | using boost::metaparse::transform; | |
24 | using boost::metaparse::one_of_c; | |
25 | using boost::metaparse::entire_input; | |
26 | ||
27 | using boost::metaparse::util::digit_to_int; | |
28 | ||
29 | using boost::mpl::int_; | |
30 | using boost::mpl::plus; | |
31 | using boost::mpl::times; | |
32 | ||
33 | /* | |
34 | * The grammar | |
35 | * | |
36 | * expression ::= ('1' | '0')* | |
37 | */ | |
38 | ||
39 | struct next_element | |
40 | { | |
41 | template <class Acc, class B> | |
42 | struct apply : plus<times<Acc, int_<2> >, B> {}; | |
43 | }; | |
44 | ||
45 | typedef | |
46 | foldl1<transform<one_of_c<'0', '1'>, digit_to_int<> >, int_<0>, next_element> | |
47 | S; | |
48 | ||
49 | typedef build_parser<entire_input<S> > binary_parser; | |
50 | ||
51 | template <class S> | |
52 | struct binary : binary_parser::apply<S>::type {}; | |
53 | ||
54 | #ifdef _STR | |
55 | # error _STR already defined | |
56 | #endif | |
57 | #define _STR BOOST_METAPARSE_STRING | |
58 | ||
b32b8144 | 59 | #if BOOST_METAPARSE_STD < 2011 |
7c673cae FG |
60 | |
61 | int main() | |
62 | { | |
63 | using std::cout; | |
64 | using std::endl; | |
65 | using boost::metaparse::string; | |
66 | ||
67 | cout | |
68 | << binary<string<'1','0','0'> >::value << endl | |
69 | << binary<string<'1','0','1','1'> >::value << endl | |
70 | << binary<string<'1'> >::value << endl; | |
71 | } | |
72 | #else | |
73 | int main() | |
74 | { | |
75 | using std::cout; | |
76 | using std::endl; | |
77 | ||
78 | cout | |
79 | << binary<_STR("100")>::value << endl | |
80 | << binary<_STR("1011")>::value << endl | |
81 | << binary<_STR("1")>::value << endl; | |
82 | } | |
83 | #endif | |
84 | ||
85 |