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#if !defined(BOOST_SPIRIT_X3_CALC9_AST_HPP)
8#define BOOST_SPIRIT_X3_CALC9_AST_HPP
9
10#include <boost/spirit/home/x3/support/ast/variant.hpp>
11#include <boost/spirit/home/x3/support/ast/position_tagged.hpp>
12#include <boost/fusion/include/io.hpp>
13#include <boost/optional.hpp>
14#include <list>
15
16namespace client { namespace ast
17{
18 ///////////////////////////////////////////////////////////////////////////
19 // The AST
20 ///////////////////////////////////////////////////////////////////////////
21 namespace x3 = boost::spirit::x3;
22
23 struct nil {};
24 struct unary;
25 struct expression;
26
27 struct variable : x3::position_tagged
28 {
29 variable(std::string const& name = "") : name(name) {}
30 std::string name;
31 };
32
33 struct operand :
34 x3::variant<
35 nil
36 , unsigned int
37 , variable
38 , x3::forward_ast<unary>
39 , x3::forward_ast<expression>
40 >
41 {
42 using base_type::base_type;
43 using base_type::operator=;
44 };
45
46 enum optoken
47 {
48 op_plus,
49 op_minus,
50 op_times,
51 op_divide,
52 op_positive,
53 op_negative,
54 op_not,
55 op_equal,
56 op_not_equal,
57 op_less,
58 op_less_equal,
59 op_greater,
60 op_greater_equal,
61 op_and,
62 op_or
63 };
64
65 struct unary
66 {
67 optoken operator_;
68 operand operand_;
69 };
70
71 struct operation : x3::position_tagged
72 {
73 optoken operator_;
74 operand operand_;
75 };
76
77 struct expression : x3::position_tagged
78 {
79 operand first;
80 std::list<operation> rest;
81 };
82
83 struct assignment : x3::position_tagged
84 {
85 variable lhs;
86 expression rhs;
87 };
88
89 struct variable_declaration
90 {
91 assignment assign;
92 };
93
94 struct if_statement;
95 struct while_statement;
96 struct statement_list;
97
98 struct statement :
99 x3::variant<
100 variable_declaration
101 , assignment
102 , boost::recursive_wrapper<if_statement>
103 , boost::recursive_wrapper<while_statement>
104 , boost::recursive_wrapper<statement_list>
105 >
106 {
107 using base_type::base_type;
108 using base_type::operator=;
109 };
110
111 struct statement_list : std::list<statement> {};
112
113 struct if_statement
114 {
115 expression condition;
116 statement then;
117 boost::optional<statement> else_;
118 };
119
120 struct while_statement
121 {
122 expression condition;
123 statement body;
124 };
125
126 // print functions for debugging
127 inline std::ostream& operator<<(std::ostream& out, nil)
128 {
129 out << "nil";
130 return out;
131 }
132
133 inline std::ostream& operator<<(std::ostream& out, variable const& var)
134 {
135 out << var.name; return out;
136 }
137}}
138
139#endif
140

source code of boost/libs/spirit/example/x3/calc/calc9/ast.hpp