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1 | /*============================================================================= |
2 | Copyright (c) 2001-2014 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 Calculator example demonstrating the grammar and semantic actions | |
10 | // using lambda functions. The parser prints code suitable for a stack | |
11 | // based virtual machine. | |
12 | // | |
13 | // [ JDG May 10, 2002 ] spirit 1 | |
14 | // [ JDG March 4, 2007 ] spirit 2 | |
15 | // [ JDG February 21, 2011 ] spirit 2.5 | |
16 | // [ JDG June 6, 2014 ] spirit x3 (from qi calc2, but using lambda functions) | |
17 | // | |
18 | /////////////////////////////////////////////////////////////////////////////// | |
19 | ||
7c673cae FG |
20 | #include <boost/spirit/home/x3.hpp> |
21 | #include <boost/spirit/home/x3/support/ast/variant.hpp> | |
22 | #include <boost/fusion/include/adapt_struct.hpp> | |
23 | ||
24 | #include <iostream> | |
25 | #include <string> | |
26 | #include <list> | |
27 | #include <numeric> | |
28 | ||
29 | namespace x3 = boost::spirit::x3; | |
30 | ||
31 | namespace client | |
32 | { | |
33 | /////////////////////////////////////////////////////////////////////////////// | |
34 | // Semantic actions | |
35 | ////////////////////////////////////////////////////////1/////////////////////// | |
36 | namespace | |
37 | { | |
38 | using x3::_attr; | |
39 | ||
40 | auto do_int = [](auto& ctx) { std::cout << "push " << _attr(ctx) << std::endl; }; | |
41 | auto do_add = []{ std::cout << "add\n"; }; | |
42 | auto do_subt = []{ std::cout << "subtract\n"; }; | |
43 | auto do_mult = []{ std::cout << "mult\n"; }; | |
44 | auto do_div = []{ std::cout << "divide\n"; }; | |
45 | auto do_neg = []{ std::cout << "negate\n"; }; | |
46 | } | |
47 | ||
48 | /////////////////////////////////////////////////////////////////////////////// | |
49 | // The calculator grammar | |
50 | /////////////////////////////////////////////////////////////////////////////// | |
51 | namespace calculator_grammar | |
52 | { | |
53 | using x3::uint_; | |
54 | using x3::char_; | |
55 | ||
56 | x3::rule<class expression> const expression("expression"); | |
57 | x3::rule<class term> const term("term"); | |
58 | x3::rule<class factor> const factor("factor"); | |
59 | ||
60 | auto const expression_def = | |
61 | term | |
62 | >> *( ('+' >> term [do_add]) | |
63 | | ('-' >> term [do_subt]) | |
64 | ) | |
65 | ; | |
66 | ||
67 | auto const term_def = | |
68 | factor | |
69 | >> *( ('*' >> factor [do_mult]) | |
70 | | ('/' >> factor [do_div]) | |
71 | ) | |
72 | ; | |
73 | ||
74 | auto const factor_def = | |
75 | uint_ [do_int] | |
76 | | '(' >> expression >> ')' | |
77 | | ('-' >> factor [do_neg]) | |
78 | | ('+' >> factor) | |
79 | ; | |
80 | ||
81 | BOOST_SPIRIT_DEFINE( | |
82 | expression | |
83 | , term | |
84 | , factor | |
85 | ); | |
86 | ||
87 | auto calculator = expression; | |
88 | } | |
89 | ||
90 | using calculator_grammar::calculator; | |
91 | ||
92 | } | |
93 | ||
94 | /////////////////////////////////////////////////////////////////////////////// | |
95 | // Main program | |
96 | /////////////////////////////////////////////////////////////////////////////// | |
97 | int | |
98 | main() | |
99 | { | |
100 | std::cout << "/////////////////////////////////////////////////////////\n\n"; | |
101 | std::cout << "Expression parser...\n\n"; | |
102 | std::cout << "/////////////////////////////////////////////////////////\n\n"; | |
103 | std::cout << "Type an expression...or [q or Q] to quit\n\n"; | |
104 | ||
105 | typedef std::string::const_iterator iterator_type; | |
106 | ||
107 | std::string str; | |
108 | while (std::getline(std::cin, str)) | |
109 | { | |
110 | if (str.empty() || str[0] == 'q' || str[0] == 'Q') | |
111 | break; | |
112 | ||
113 | auto& calc = client::calculator; // Our grammar | |
114 | ||
115 | iterator_type iter = str.begin(); | |
116 | iterator_type end = str.end(); | |
117 | boost::spirit::x3::ascii::space_type space; | |
118 | bool r = phrase_parse(iter, end, calc, space); | |
119 | ||
120 | if (r && iter == end) | |
121 | { | |
122 | std::cout << "-------------------------\n"; | |
123 | std::cout << "Parsing succeeded\n"; | |
124 | std::cout << "-------------------------\n"; | |
125 | } | |
126 | else | |
127 | { | |
128 | std::string rest(iter, end); | |
129 | std::cout << "-------------------------\n"; | |
130 | std::cout << "Parsing failed\n"; | |
131 | std::cout << "stopped at: \"" << rest << "\"\n"; | |
132 | std::cout << "-------------------------\n"; | |
133 | } | |
134 | } | |
135 | ||
136 | std::cout << "Bye... :-) \n\n"; | |
137 | return 0; | |
138 | } |