1#ifndef __LIBUTIL_CALCULATOR_H__
2#define __LIBUTIL_CALCULATOR_H__
3
4#include <sstream>
5
6#include "String.h"
7#include "Map.h"
8#include "Assert.h"
9
10namespace LibUtil
11{
12 using std::istringstream;
13
14 /*
15 * program:
16 * END // END is end-of-input
17 * expr_list END
18 *
19 * expr_list:
20 * expression SEP expr_list // SEP is semicolon
21 * expression
22 * print expression
23 * print STRING
24 * print STRING expression
25 * print STRING expression SEP expr_list
26 *
27 *
28 * expression:
29 * expression + term
30 * expression - term
31 * term
32 *
33 * term:
34 * term / primary
35 * term * primary
36 * primary
37 *
38 * primary:
39 * NUMBER
40 * NAME
41 * NAME = expression
42 * NAME string expression // NAME is print
43 * - primary
44 * ( expression )
45 *
46 * string:
47 *
48 **/
49
50 class Calculator
51 {
52 protected:
53 enum Token
54 {
55 NAME, NAME2, NUMBER, STRING, END,
56 PLUS = '+', MINUS = '-', MUL = '*', DIV = '/',
57 SEP = ';', ASSIGN = '=', LP = '(', RP = ')'
58 };
59
60 public:
61 Calculator();
62 virtual ~Calculator();
63
64 public:
65 void reset();
66 void evaluateString(const String& str_);
67
68 protected:
69 Token getToken(istringstream& ist_);
70 double prim(istringstream& ist_, bool is_get_);
71 double term(istringstream& ist_, bool is_get_);
72 double expr(istringstream& ist_, bool is_get_);
73 virtual double getEnvVar(const String& var_name_) const;
74
75 protected:
76 String m_reserved_chars_;
77 Map<double> m_var_;
78
79 Token m_curr_token_;
80 double m_value_number_;
81 String m_value_string_;
82 }; // class Calculator
83} // namespace LibUtil
84
85#endif // __LIBUTIL_CALCULATOR_H__
86