svn-gvsig-desktop / trunk / org.gvsig.desktop / org.gvsig.desktop.library / org.gvsig.expressionevaluator / org.gvsig.expressionevaluator.lib / org.gvsig.expressionevaluator.lib.api / src / main / java / org / gvsig / expressionevaluator / spi / AbstractLexicalAnalyzer.java @ 43983
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1 | 43983 | jjdelcerro | package org.gvsig.expressionevaluator.spi; |
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2 | |||
3 | import org.gvsig.expressionevaluator.LexicalAnalyzer; |
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4 | import java.text.NumberFormat; |
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5 | import java.text.ParsePosition; |
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6 | import java.util.HashMap; |
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7 | import java.util.Locale; |
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8 | import java.util.Map; |
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9 | import java.util.Stack; |
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10 | import org.gvsig.expressionevaluator.ExpressionSyntaxException; |
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11 | import org.gvsig.tools.lang.Cloneable; |
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12 | |||
13 | public abstract class AbstractLexicalAnalyzer implements LexicalAnalyzer { |
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14 | |||
15 | protected class DefaultToken implements Token { |
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16 | |||
17 | private int type; |
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18 | private String literal; |
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19 | private Object value; |
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20 | |||
21 | public DefaultToken() {
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22 | } |
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23 | |||
24 | @Override
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25 | public Token clone() throws CloneNotSupportedException { |
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26 | // We will assume that the properties of the class are immutable, so
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27 | // it would suffice to call the super class.
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28 | DefaultToken other = (DefaultToken) super.clone();
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29 | return other;
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30 | } |
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31 | |||
32 | @Override
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33 | public void set(int type, String literal) { |
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34 | this.set(type, literal, literal);
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35 | } |
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36 | |||
37 | @Override
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38 | public void set(int type, String literal, Object value) { |
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39 | this.literal = literal;
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40 | this.type = type;
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41 | this.value = value;
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42 | } |
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43 | |||
44 | @Override
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45 | public int getType() { |
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46 | return type;
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47 | } |
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48 | |||
49 | @Override
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50 | public Object getValue() { |
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51 | return value;
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52 | } |
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53 | |||
54 | @Override
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55 | public String getLiteral() { |
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56 | return literal;
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57 | } |
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58 | |||
59 | public void setLiteral(String literal) { |
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60 | this.literal = literal;
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61 | } |
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62 | |||
63 | } |
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64 | |||
65 | protected class Buffer implements Cloneable { |
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66 | |||
67 | StringBuilder builder;
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68 | |||
69 | public Buffer() { |
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70 | this.builder = new StringBuilder(); |
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71 | } |
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72 | |||
73 | @Override
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74 | public Buffer clone() throws CloneNotSupportedException { |
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75 | Buffer other = (Buffer) super.clone(); |
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76 | other.builder = new StringBuilder(builder); |
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77 | return other;
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78 | } |
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79 | |||
80 | public void clear() { |
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81 | builder.delete(0, builder.length());
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82 | } |
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83 | |||
84 | public void add(char ch) { |
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85 | builder.append(ch); |
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86 | } |
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87 | |||
88 | public int length() { |
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89 | return this.builder.length(); |
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90 | } |
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91 | |||
92 | @Override
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93 | public String toString() { |
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94 | return this.builder.toString(); |
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95 | } |
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96 | } |
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97 | |||
98 | protected static final char EOF = 0; |
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99 | |||
100 | private NumberFormat nf; |
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101 | private ParsePosition nfPos; |
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102 | private Stack<Integer> states; |
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103 | private String source; |
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104 | private int position; |
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105 | |||
106 | protected Buffer buffer; |
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107 | protected Token token;
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108 | protected Map<String, Integer> tokens; |
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109 | |||
110 | public AbstractLexicalAnalyzer(String source) { |
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111 | this.position = 0; |
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112 | this.source = source;
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113 | this.states = new Stack<>(); |
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114 | this.buffer = new Buffer(); |
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115 | this.token = this.createToken(); |
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116 | |||
117 | this.nf = NumberFormat.getInstance(Locale.UK); |
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118 | this.nfPos = new ParsePosition(0); |
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119 | |||
120 | this.tokens = new HashMap<>(); |
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121 | } |
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122 | |||
123 | public AbstractLexicalAnalyzer() {
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124 | this(null); |
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125 | } |
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126 | |||
127 | protected Token createToken() {
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128 | return new DefaultToken(); |
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129 | } |
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130 | |||
131 | @Override
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132 | public LexicalAnalyzer clone() throws CloneNotSupportedException { |
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133 | AbstractLexicalAnalyzer other = (AbstractLexicalAnalyzer) super.clone();
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134 | other.nf = NumberFormat.getInstance(Locale.UK); |
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135 | other.nfPos = new ParsePosition(0); |
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136 | other.buffer = buffer.clone(); |
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137 | other.token = token.clone(); |
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138 | other.states = new Stack<>(); |
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139 | other.states.addAll(states); |
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140 | other.tokens = new HashMap<>(tokens); |
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141 | return other;
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142 | } |
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143 | |||
144 | @Override
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145 | public void setSource(String source) { |
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146 | this.source = source;
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147 | this.position = 0; |
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148 | } |
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149 | |||
150 | @Override
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151 | public String getSource() { |
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152 | return this.source; |
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153 | } |
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154 | |||
155 | @Override
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156 | public Token next() {
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157 | return getToken();
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158 | } |
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159 | |||
160 | @Override
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161 | public Token look() {
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162 | push_state(); |
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163 | try {
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164 | return getToken();
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165 | } finally {
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166 | pop_state(); |
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167 | } |
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168 | } |
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169 | |||
170 | abstract protected Token getToken(); |
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171 | |||
172 | protected void push_state() { |
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173 | this.states.push(position);
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174 | } |
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175 | |||
176 | protected void pop_state() { |
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177 | position = this.states.pop();
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178 | } |
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179 | |||
180 | @Override
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181 | public int getPosition() { |
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182 | return position;
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183 | } |
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184 | |||
185 | public boolean isEOF() { |
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186 | return this.position >= this.source.length(); |
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187 | } |
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188 | |||
189 | protected void skipblanks() { |
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190 | if (isEOF()) {
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191 | return;
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192 | } |
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193 | char ch = getch();
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194 | while (ch != EOF && Character.isSpaceChar(ch)) { |
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195 | ch = getch(); |
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196 | } |
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197 | ungetch(); |
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198 | } |
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199 | |||
200 | protected char lookch() { |
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201 | if (this.position >= this.source.length()) { |
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202 | return EOF;
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203 | } |
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204 | return this.source.charAt(this.position); |
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205 | } |
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206 | |||
207 | protected char getch() { |
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208 | if (this.position >= this.source.length()) { |
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209 | return EOF;
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210 | } |
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211 | return this.source.charAt(this.position++); |
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212 | } |
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213 | |||
214 | protected void ungetch() { |
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215 | this.position--;
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216 | if (this.position < 0) { |
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217 | this.position = 0; |
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218 | } |
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219 | } |
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220 | |||
221 | protected void parseString() { |
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222 | buffer.clear(); |
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223 | char ch = getch();
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224 | while (true) { |
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225 | if (ch == EOF) {
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226 | throw new ExpressionSyntaxException("Found end of source and expected end of string", this); |
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227 | } |
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228 | if (ch == '\'') { |
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229 | ch = getch(); |
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230 | if (ch == EOF) {
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231 | break;
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232 | } |
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233 | if (ch != '\'') { |
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234 | ungetch(); |
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235 | break;
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236 | } |
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237 | } |
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238 | buffer.add(ch); |
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239 | ch = getch(); |
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240 | } |
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241 | token.set(Token.STRING_LITERAL, buffer.toString()); |
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242 | } |
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243 | |||
244 | protected void parseNumber() { |
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245 | this.nfPos.setIndex(this.position); |
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246 | Number n = nf.parse(source, this.nfPos); |
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247 | if (this.nfPos.getIndex() == this.position) { |
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248 | throw new RuntimeException("Expected a number at position " + this.nfPos.getIndex() + "."); |
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249 | } |
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250 | String literal = source.substring(this.position, this.nfPos.getIndex()); |
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251 | this.position = this.nfPos.getIndex(); |
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252 | if (n instanceof Long || n instanceof Integer) { |
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253 | token.set(Token.INTEGER_LITERAL, literal, n); |
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254 | } else {
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255 | token.set(Token.FLOATING_POINT_LITERAL, literal, n); |
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256 | } |
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257 | } |
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258 | } |