1 /*=============================================================================
2 Copyright (c) 2002-2003 Joel de Guzman
3 Copyright (c) 2002 Juan Carlos Arevalo-Baeza
4 http://spirit.sourceforge.net/
5
6 Use, modification and distribution is subject to the Boost Software
7 License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
8 http://www.boost.org/LICENSE_1_0.txt)
9 =============================================================================*/
10 #include <boost/spirit/include/classic_core.hpp>
11 #include <boost/spirit/include/classic_functor_parser.hpp>
12 #include <boost/spirit/include/classic_assign_actor.hpp>
13 #include <iostream>
14 #include <vector>
15 #include <string>
16
17 ///////////////////////////////////////////////////////////////////////////////
18 //
19 // Demonstrates the functor_parser. This is discussed in the
20 // "Functor Parser" chapter in the Spirit User's Guide.
21 //
22 ///////////////////////////////////////////////////////////////////////////////
23 using namespace std;
24 using namespace BOOST_SPIRIT_CLASSIC_NS;
25
26 ///////////////////////////////////////////////////////////////////////////////
27 //
28 // Our parser functor
29 //
30 ///////////////////////////////////////////////////////////////////////////////
31 struct number_parser
32 {
33 typedef int result_t;
34 template <typename ScannerT>
35 int
operator ()number_parser36 operator()(ScannerT const& scan, result_t& result) const
37 {
38 if (scan.at_end())
39 return -1;
40
41 char ch = *scan;
42 if (ch < '0' || ch > '9')
43 return -1;
44
45 result = 0;
46 int len = 0;
47
48 do
49 {
50 result = result*10 + int(ch - '0');
51 ++len;
52 ++scan;
53 } while (!scan.at_end() && (ch = *scan, ch >= '0' && ch <= '9'));
54
55 return len;
56 }
57 };
58
59 functor_parser<number_parser> number_parser_p;
60
61 ///////////////////////////////////////////////////////////////////////////////
62 //
63 // Our number parser functions
64 //
65 ///////////////////////////////////////////////////////////////////////////////
66 bool
parse_number(char const * str,int & n)67 parse_number(char const* str, int& n)
68 {
69 return parse(str, lexeme_d[number_parser_p[assign_a(n)]], space_p).full;
70 }
71
72 bool
parse_numbers(char const * str,std::vector<int> & n)73 parse_numbers(char const* str, std::vector<int>& n)
74 {
75 return
76 parse(
77 str,
78 lexeme_d[number_parser_p[push_back_a(n)]]
79 >> *(',' >> lexeme_d[number_parser_p[push_back_a(n)]]),
80 space_p
81 ).full;
82 }
83
84 ////////////////////////////////////////////////////////////////////////////
85 //
86 // Main program
87 //
88 ////////////////////////////////////////////////////////////////////////////
89 int
main()90 main()
91 {
92 cout << "/////////////////////////////////////////////////////////\n\n";
93 cout << "\t\tA number parser implemented as a functor for Spirit...\n\n";
94 cout << "/////////////////////////////////////////////////////////\n\n";
95
96 cout << "Give me an integer number command\n";
97 cout << "Commands:\n";
98 cout << " A <num> --> parses a single number\n";
99 cout << " B <num>, <num>, ... --> parses a series of numbers ";
100 cout << "separated by commas\n";
101 cout << " Q --> quit\n\n";
102
103 string str;
104 while (getline(cin, str))
105 {
106 if (str.empty() || str[0] == 'q' || str[0] == 'Q')
107 break;
108
109 else if (str[0] == 'a' || str[0] == 'A')
110 {
111 int n;
112 if (parse_number(str.c_str()+1, n))
113 {
114 cout << "-------------------------\n";
115 cout << "Parsing succeeded\n";
116 cout << str << " Parses OK: " << n << endl;
117 cout << "-------------------------\n";
118 }
119 else
120 {
121 cout << "-------------------------\n";
122 cout << "Parsing failed\n";
123 cout << "-------------------------\n";
124 }
125 }
126
127 else if (str[0] == 'b' || str[0] == 'B')
128 {
129 std::vector<int> n;
130 if (parse_numbers(str.c_str()+1, n))
131 {
132 cout << "-------------------------\n";
133 cout << "Parsing succeeded\n";
134 int size = n.size();
135 cout << str << " Parses OK: " << size << " number(s): " << n[0];
136 for (int i = 1; i < size; ++i) {
137 cout << ", " << n[i];
138 }
139 cout << endl;
140 cout << "-------------------------\n";
141 }
142 else
143 {
144 cout << "-------------------------\n";
145 cout << "Parsing failed\n";
146 cout << "-------------------------\n";
147 }
148 }
149
150 else
151 {
152 cout << "-------------------------\n";
153 cout << "Unrecognized command!!";
154 cout << "-------------------------\n";
155 }
156 }
157
158 cout << "Bye... :-) \n\n";
159 return 0;
160 }
161