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/foldl_reject_incomplete.hpp>
7 #include <boost/metaparse/foldl_reject_incomplete1.hpp>
8 #include <boost/metaparse/lit_c.hpp>
9 #include <boost/metaparse/transform.hpp>
10 #include <boost/metaparse/one_char_except_c.hpp>
11 #include <boost/metaparse/one_of.hpp>
12 #include <boost/metaparse/always_c.hpp>
13 #include <boost/metaparse/build_parser.hpp>
14 #include <boost/metaparse/middle_of.hpp>
15 #include <boost/metaparse/entire_input.hpp>
16 #include <boost/metaparse/string.hpp>
17
18 #include <boost/detail/iterator.hpp>
19 #include <boost/xpressive/xpressive.hpp>
20
21 #include <boost/mpl/bool.hpp>
22 #include <boost/mpl/string.hpp>
23
24 using boost::metaparse::foldl_reject_incomplete;
25 using boost::metaparse::foldl_reject_incomplete1;
26 using boost::metaparse::lit_c;
27 using boost::metaparse::transform;
28 using boost::metaparse::build_parser;
29 using boost::metaparse::one_of;
30 using boost::metaparse::always_c;
31 using boost::metaparse::middle_of;
32 using boost::metaparse::one_char_except_c;
33 using boost::metaparse::entire_input;
34
35 using boost::mpl::c_str;
36 using boost::mpl::true_;
37 using boost::mpl::false_;
38
39 using boost::xpressive::sregex;
40 using boost::xpressive::as_xpr;
41
42 /*
43 * Results of parsing
44 */
45
46 template <class T>
47 struct has_value
48 {
49 typedef T type;
50 static const sregex value;
51 };
52
53 template <class T>
54 const sregex has_value<T>::value = T::run();
55
56 struct r_epsilon : has_value<r_epsilon>
57 {
runr_epsilon58 static sregex run()
59 {
60 return as_xpr("");
61 }
62 };
63
64 struct r_any_char : has_value<r_any_char>
65 {
runr_any_char66 static sregex run()
67 {
68 return boost::xpressive::_;
69 }
70 };
71
72 struct r_char_lit
73 {
74 template <class C>
75 struct apply : has_value<apply<C> >
76 {
runr_char_lit::apply77 static sregex run()
78 {
79 return as_xpr(C::type::value);
80 }
81 };
82 };
83
84 struct r_append
85 {
86 template <class A, class B>
87 struct apply : has_value<apply<B, A> >
88 {
runr_append::apply89 static sregex run()
90 {
91 return A::type::run() >> B::type::run();
92 }
93 };
94 };
95
96 /*
97 * The grammar
98 *
99 * regexp ::= (bracket_expr | non_bracket_expr)*
100 * non_bracket_expr ::= '.' | char_lit
101 * bracket_expr ::= '(' regexp ')'
102 * char_lit ::= any character except: . ( )
103 */
104
105 typedef
106 foldl_reject_incomplete1<
107 one_of<
108 always_c<'.', r_any_char>,
109 transform<one_char_except_c<'.', '(', ')'>, r_char_lit>
110 >,
111 r_epsilon,
112 r_append
113 >
114 non_bracket_expr;
115
116 typedef middle_of<lit_c<'('>, non_bracket_expr, lit_c<')'> > bracket_expr;
117
118 typedef
119 foldl_reject_incomplete<
120 one_of<bracket_expr, non_bracket_expr>,
121 r_epsilon,
122 r_append
123 >
124 regexp;
125
126 typedef build_parser<entire_input<regexp> > regexp_parser;
127
test_string(const std::string & s)128 void test_string(const std::string& s)
129 {
130 using boost::xpressive::regex_match;
131 using boost::xpressive::smatch;
132 using boost::mpl::apply_wrap1;
133
134 using std::cout;
135 using std::endl;
136
137 #if BOOST_METAPARSE_STD < 2011
138 typedef boost::metaparse::string<'.','(','b','c',')'> regexp;
139 #else
140 typedef BOOST_METAPARSE_STRING(".(bc)") regexp;
141 #endif
142
143 const sregex re = apply_wrap1<regexp_parser, regexp>::type::value;
144 smatch w;
145
146 cout
147 << s << (regex_match(s, w, re) ? " matches " : " doesn't match ")
148 << c_str<regexp>::type::value
149 << endl;
150 }
151
main()152 int main()
153 {
154 test_string("abc");
155 test_string("aba");
156 }
157
158
159