1 /*=============================================================================
2 Copyright (c) 2002-2010 Joel de Guzman
3
4 Distributed under the Boost Software License, Version 1.0. (See accompanying
5 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6 =============================================================================*/
7 ///////////////////////////////////////////////////////////////////////////////
8 //
9 // A complex number micro parser.
10 //
11 // [ JDG May 10, 2002 ] spirit1
12 // [ JDG May 9, 2007 ] spirit2
13 //
14 ///////////////////////////////////////////////////////////////////////////////
15
16 #include <boost/config/warning_disable.hpp>
17 #include <boost/spirit/include/qi.hpp>
18 #include <boost/spirit/include/phoenix_core.hpp>
19 #include <boost/spirit/include/phoenix_operator.hpp>
20
21 #include <iostream>
22 #include <string>
23 #include <complex>
24
25 ///////////////////////////////////////////////////////////////////////////////
26 // Our complex number parser/compiler
27 ///////////////////////////////////////////////////////////////////////////////
28 //[tutorial_complex_number
29 namespace client
30 {
31 template <typename Iterator>
parse_complex(Iterator first,Iterator last,std::complex<double> & c)32 bool parse_complex(Iterator first, Iterator last, std::complex<double>& c)
33 {
34 using boost::spirit::qi::double_;
35 using boost::spirit::qi::_1;
36 using boost::spirit::qi::phrase_parse;
37 using boost::spirit::ascii::space;
38 using boost::phoenix::ref;
39
40 double rN = 0.0;
41 double iN = 0.0;
42 bool r = phrase_parse(first, last,
43
44 // Begin grammar
45 (
46 '(' >> double_[ref(rN) = _1]
47 >> -(',' >> double_[ref(iN) = _1]) >> ')'
48 | double_[ref(rN) = _1]
49 ),
50 // End grammar
51
52 space);
53
54 if (!r || first != last) // fail if we did not get a full match
55 return false;
56 c = std::complex<double>(rN, iN);
57 return r;
58 }
59 }
60 //]
61
62 ////////////////////////////////////////////////////////////////////////////
63 // Main program
64 ////////////////////////////////////////////////////////////////////////////
65 int
main()66 main()
67 {
68 std::cout << "/////////////////////////////////////////////////////////\n\n";
69 std::cout << "\t\tA complex number micro parser for Spirit...\n\n";
70 std::cout << "/////////////////////////////////////////////////////////\n\n";
71
72 std::cout << "Give me a complex number of the form r or (r) or (r,i) \n";
73 std::cout << "Type [q or Q] to quit\n\n";
74
75 std::string str;
76 while (getline(std::cin, str))
77 {
78 if (str.empty() || str[0] == 'q' || str[0] == 'Q')
79 break;
80
81 std::complex<double> c;
82 if (client::parse_complex(str.begin(), str.end(), c))
83 {
84 std::cout << "-------------------------\n";
85 std::cout << "Parsing succeeded\n";
86 std::cout << "got: " << c << std::endl;
87 std::cout << "\n-------------------------\n";
88 }
89 else
90 {
91 std::cout << "-------------------------\n";
92 std::cout << "Parsing failed\n";
93 std::cout << "-------------------------\n";
94 }
95 }
96
97 std::cout << "Bye... :-) \n\n";
98 return 0;
99 }
100
101
102