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1 /* Test file for C++ parsers using variants.
2 Based on an example by Michiel De Wilde <mdewilde.agilent@gmail.com>. */
3 %debug
4 %skeleton "lalr1-fusion.cc"
5 %defines
6 %define variant
7
8 %code requires // *.hh
9 {
10 #include <list>
11 #include <string>
12 typedef std::list<std::string> strings_type;
13 }
14
15 %code // *.cc
16 {
17 #include <algorithm>
18 #include <iostream>
19 #include <iterator>
20 #include <sstream>
21
22 // Prototype of the yylex function providing subsequent tokens.
23 static yy::parser::token_type yylex(yy::parser::semantic_type* yylval);
24
25 // Printing a list of strings.
26 // Koening look up will look into std, since that's an std::list.
27 namespace std
28 {
29 std::ostream&
30 operator<<(std::ostream& o, const strings_type& s)
31 {
32 std::copy(s.begin(), s.end(),
33 std::ostream_iterator<strings_type::value_type>(o, "\n"));
34 return o;
35 }
36 }
37
38 // Conversion to string.
39 template <typename T>
40 inline
41 std::string
42 string_cast (const T& t)
43 {
44 std::ostringstream o;
45 o << t;
46 return o.str();
47 }
48 }
49
50 %token <std::string> TEXT;
51 %token <int> NUMBER;
52 %printer { debug_stream () << $$; } <int> <std::string> <strings_type>;
53 %token END_OF_FILE 0;
54
55 %type <std::string> item;
56 %type <strings_type> list;
57
58 %%
59
60 result:
61 list { std::cout << $1 << std::endl; }
62 ;
63
64 list:
65 /* nothing */ { /* Generates an empty string list */ }
66 | list item { std::swap ($$, $1); $$.push_back ($2); }
67 ;
68
69 item:
70 TEXT { std::swap ($$, $1); }
71 | NUMBER { $$ = string_cast ($1); }
72 ;
73 %%
74
75 // The yylex function providing subsequent tokens:
76 // TEXT "I have three numbers for you:"
77 // NUMBER 1
78 // NUMBER 2
79 // NUMBER 3
80 // TEXT " and that's all!"
81 // END_OF_FILE
82
83 static
84 yy::parser::token_type
85 yylex (yy::parser::semantic_type* yylval)
86 {
87 static int stage = 0;
88 yy::parser::token_type result;
89
90 switch (stage)
91 {
92 case 0:
93 yylval->build<std::string> () =
94 std::string ("I have three numbers for you.");
95 result = yy::parser::token::TEXT;
96 break;
97 case 1:
98 case 2:
99 case 3:
100 yylval->build<int> () = stage;
101 result = yy::parser::token::NUMBER;
102 break;
103 case 4:
104 yylval->build<std::string> () = std::string ("And that's all!");
105 result = yy::parser::token::TEXT;
106 break;
107 default:
108 result = yy::parser::token::END_OF_FILE;
109 break;
110 }
111
112 stage++;
113 return result;
114 }
115
116 // Mandatory error function
117 void
118 yy::parser::error (const yy::parser::location_type& yylloc,
119 const std::string& message)
120 {
121 std::cerr << yylloc << ": " << message << std::endl;
122 }
123
124 int
125 main (int argc, char *argv[])
126 {
127 yy::parser p;
128 p.set_debug_level (!!getenv ("YYDEBUG"));
129 p.parse ();
130 }
131
132 // Local Variables:
133 // mode: C++
134 // End: