1 /*=============================================================================
2 Copyright (c) 2001-2011 Hartmut Kaiser
3 http://spirit.sourceforge.net/
4
5 Distributed under the Boost Software License, Version 1.0. (See accompanying
6 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7 =============================================================================*/
8 //[porting_guide_qi_includes
9 #include <boost/spirit/include/qi.hpp>
10 #include <boost/spirit/include/phoenix_operator.hpp>
11 #include <iostream>
12 #include <string>
13 #include <algorithm>
14 //]
15
16 //[porting_guide_qi_namespace
17 using namespace boost::spirit;
18 //]
19
20 //[porting_guide_qi_grammar
21 template <typename Iterator>
22 struct roman : qi::grammar<Iterator, unsigned()>
23 {
romanroman24 roman() : roman::base_type(first)
25 {
26 hundreds.add
27 ("C" , 100)("CC" , 200)("CCC" , 300)("CD" , 400)("D" , 500)
28 ("DC" , 600)("DCC" , 700)("DCCC" , 800)("CM" , 900) ;
29
30 tens.add
31 ("X" , 10)("XX" , 20)("XXX" , 30)("XL" , 40)("L" , 50)
32 ("LX" , 60)("LXX" , 70)("LXXX" , 80)("XC" , 90) ;
33
34 ones.add
35 ("I" , 1)("II" , 2)("III" , 3)("IV" , 4)("V" , 5)
36 ("VI" , 6)("VII" , 7)("VIII" , 8)("IX" , 9) ;
37
38 // qi::_val refers to the attribute of the rule on the left hand side
39 first = eps [qi::_val = 0]
40 >> ( +lit('M') [qi::_val += 1000]
41 || hundreds [qi::_val += qi::_1]
42 || tens [qi::_val += qi::_1]
43 || ones [qi::_val += qi::_1]
44 ) ;
45 }
46
47 qi::rule<Iterator, unsigned()> first;
48 qi::symbols<char, unsigned> hundreds;
49 qi::symbols<char, unsigned> tens;
50 qi::symbols<char, unsigned> ones;
51 };
52 //]
53
main()54 int main()
55 {
56 {
57 //[porting_guide_qi_parse
58 std::string input("1,1");
59 std::string::iterator it = input.begin();
60 bool result = qi::parse(it, input.end(), qi::int_);
61
62 if (result)
63 std::cout << "successful match!\n";
64
65 if (it == input.end())
66 std::cout << "full match!\n";
67 else
68 std::cout << "stopped at: " << std::string(it, input.end()) << "\n";
69
70 // seldomly needed: use std::distance to calculate the length of the match
71 std::cout << "matched length: " << std::distance(input.begin(), it) << "\n";
72 //]
73 }
74
75 {
76 //[porting_guide_qi_phrase_parse
77 std::string input(" 1, 1");
78 std::string::iterator it = input.begin();
79 bool result = qi::phrase_parse(it, input.end(), qi::int_, ascii::space);
80
81 if (result)
82 std::cout << "successful match!\n";
83
84 if (it == input.end())
85 std::cout << "full match!\n";
86 else
87 std::cout << "stopped at: " << std::string(it, input.end()) << "\n";
88
89 // seldomly needed: use std::distance to calculate the length of the match
90 std::cout << "matched length: " << std::distance(input.begin(), it) << "\n";
91 //]
92 }
93
94 {
95 //[porting_guide_qi_use_grammar
96 std::string input("MMIX"); // MMIX == 2009
97 std::string::iterator it = input.begin();
98 unsigned value = 0;
99 roman<std::string::iterator> r;
100 if (qi::parse(it, input.end(), r, value))
101 std::cout << "successfully matched: " << value << "\n";
102 //]
103 }
104 return 0;
105 }
106
107