1#include "Calculator.h"
2
3#include <cctype>
4#include <iostream>
5
6namespace LibUtil
7{
8 using std::cout;

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18 {}
19
20 void Calculator::reset()
21 {
22 m_var_.clear();
23 return;
24 }
25
26 void Calculator::evaluateString(const String& str_)
27 {
28 istringstream ist(str_);
29 while(ist)
30 {
31 getToken(ist);
32 if(m_curr_token_ == END) break;
33 if(m_curr_token_ == SEP) continue;
34 if((m_curr_token_ == NAME) && (m_value_string_ == "print"))
35 {
36 getToken(ist);
37
38 if(m_curr_token_ == STRING)
39 {
40 String print_str = m_value_string_;
41
42 getToken(ist);
43 if(m_curr_token_ == SEP)
44 {
45 cout << print_str << endl;
46 }
47 else
48 {
49 double v = expr(ist, false);
50 cout << scientific << print_str << v << endl;
51 }
52 }
53 else
54 {
55 double v = expr(ist, false);
56 cout << scientific << v << endl;
57 }
58 }
59 else
60 {
61 expr(ist, false);
62 }
63 }
64 return;
65 }
66
67 Calculator::Token Calculator::getToken(istringstream& ist_)
68 {
69 char ch;
70 do
71 {
72 ist_.get(ch);

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141 else
142 {
143 String error_msg = "[Error] Bad token: '" + String(ch) + "'";
144 throw Exception(error_msg);
145 }
146 }
147 }
148
149 double Calculator::prim(istringstream& ist_, bool is_get_)
150 {
151 if(is_get_)
152 {
153 getToken(ist_);
154 }
155
156 double v;
157 switch(m_curr_token_)
158 {
159 case NUMBER:
160 v = m_value_number_;
161 getToken(ist_);
162 return v;
163 case NAME:
164 if(getToken(ist_) == ASSIGN)
165 {
166 String var_name = m_value_string_;
167 v = expr(ist_, true);
168 m_var_.set(var_name, v);
169 }
170 else
171 {
172 v = m_var_.get(m_value_string_);
173 }
174 return v;
175 case NAME2:
176 v = getEnvVar(m_value_string_);
177 getToken(ist_);
178 return v;
179 case MINUS:
180 return -prim(ist_, true);
181 case LP:
182 v = expr(ist_, true);
183 ASSERT((m_curr_token_ == RP), "[Error] ')' expected");
184 getToken(ist_);
185 return v;
186 default:
187 ASSERT(0, "[Error] primary expected, get: '" + String(int(m_curr_token_)) + "'");
188 }
189 }
190
191 double Calculator::term(istringstream& ist_, bool is_get_)
192 {
193 double left = prim(ist_, is_get_);
194
195 while(1)
196 {
197 double d;
198 switch(m_curr_token_)
199 {
200 case MUL:
201 left *= prim(ist_, true);
202 break;
203 case DIV:
204 d = prim(ist_, true);
205 ASSERT(d, "[Error] divided by 0");
206 left /= d;
207 break;
208 default:
209 return left;
210 }
211 }
212 }
213
214 double Calculator::expr(istringstream& ist_, bool is_get_)
215 {
216 double left = term(ist_, is_get_);
217
218 while(1)
219 {
220 switch(m_curr_token_)
221 {
222 case PLUS:
223 left += term(ist_, true);
224 break;
225 case MINUS:
226 left -= term(ist_, true);
227 break;
228 default:
229 return left;
230 }
231 }
232 }
233
234 double Calculator::getEnvVar(const String& var_name_) const
235 {
236 return m_var_.get(var_name_);
237 }
238} // namespace LibUtil
239