blob: 9ef385ff774f86f94d262ba1dafdf596c3138024 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
|
%code requires{
#include <cassert>
extern const Expression *g_root; // A way of getting the AST out
//! This is to fix problems when generating C++
// We are declaring the functions provided by Flex, so
// that Bison generated code can call them.
int yylex(void);
void yyerror(const char *);
}
// Represents the value associated with any kind of
// AST node.
%union{
const Expression *expr;
double number;
std::string *string;
}
%token T_TIMES T_PLUS T_DIVIDE T_MINUS T_LBRACKET T_RBRACKET T_LOG T_EXP T_SQRT T_NUMBER T_VARIABLE
%type <expr> EXPR TERM FACTOR
%type <number> T_NUMBER
%type <string> T_VARIABLE T_LOG T_EXP T_SQRT FUNCTION_NAME
%start ROOT
%%
ROOT : EXPR { g_root = $1; }
EXPR : TERM { $$ = $1; }
| EXPR T_PLUS TERM { $$ = new AddOperator($1, $3); }
| EXPR T_MINUS TERM { $$ = new SubOperator($1, $3); }
TERM : FACTOR { $$ = $1; }
| TERM T_TIMES FACTOR { $$ = new MulOperator($1, $3); }
| TERM T_DIVIDE FACTOR { $$ = new DivOperator($1, $3); }
FACTOR : T_NUMBER { $$ = new Number( $1 ); }
| T_VARIABLE { $$ = new Variable( *$1 ); }
| T_LBRACKET EXPR T_RBRACKET { $$ = $2; }
| FUNCTION_NAME FACTOR {
if(*$1 == "log") {
$$ = new LogFunction($2);
} else if(*$1 == "exp") {
$$ = new ExpFunction($2);
} else {
$$ = new SqrtFunction($2);
}}
FUNCTION_NAME : T_LOG { $$ = new std::string("log"); }
| T_EXP { $$ = new std::string("exp"); }
| T_SQRT { $$ = new std::string("sqrt"); }
%%
const Expression *g_root; // Definition of variable (to match declaration earlier)
const Expression *parseAST()
{
g_root=0;
yyparse();
return g_root;
}
|
