1 | package antlr; |
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2 | |
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3 | /* ANTLR Translator Generator |
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4 | * Project led by Terence Parr at http://www.cs.usfca.edu |
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5 | * Software rights: http://www.antlr.org/license.html |
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6 | * |
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7 | * $Id: //depot/code/org.antlr/release/antlr-2.7.7/antlr/AlternativeBlock.java#2 $ |
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8 | */ |
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9 | |
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10 | import antlr.collections.impl.Vector; |
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11 | |
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12 | /**A list of alternatives */ |
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13 | class AlternativeBlock extends AlternativeElement { |
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14 | protected String initAction = null; // string for init action {...} |
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15 | protected Vector alternatives; // Contains Alternatives |
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16 | |
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17 | protected String label; // can label a looping block to break out of it. |
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18 | |
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19 | protected int alti, altj; // which alts are being compared at the moment with |
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20 | // deterministic()? |
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21 | protected int analysisAlt; // which alt are we computing look on? Must be alti or altj |
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22 | |
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23 | protected boolean hasAnAction = false; // does any alt have an action? |
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24 | protected boolean hasASynPred = false; // does any alt have a syntactic predicate? |
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25 | |
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26 | protected int ID = 0; // used to generate unique variables |
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27 | protected static int nblks; // how many blocks have we allocated? |
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28 | boolean not = false; // true if block is inverted. |
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29 | |
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30 | boolean greedy = true; // Blocks are greedy by default |
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31 | boolean greedySet = false; // but, if not explicitly greedy, warning might be generated |
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32 | |
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33 | protected boolean doAutoGen = true; // false if no AST (or text) to be generated for block |
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34 | |
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35 | protected boolean warnWhenFollowAmbig = true; // warn when an empty path or exit path |
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36 | |
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37 | protected boolean generateAmbigWarnings = true; // the general warning "shut-up" mechanism |
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38 | // conflicts with alt of subrule. |
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39 | // Turning this off will suppress stuff |
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40 | // like the if-then-else ambig. |
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41 | |
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42 | public AlternativeBlock(Grammar g) { |
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43 | super(g); |
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44 | alternatives = new Vector(5); |
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45 | this.not = false; |
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46 | nblks++; |
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47 | ID = nblks; |
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48 | } |
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49 | |
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50 | public AlternativeBlock(Grammar g, Token start, boolean not) { |
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51 | super(g, start); |
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52 | alternatives = new Vector(5); |
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53 | // this.line = start.getLine(); |
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54 | // this.column = start.getColumn(); |
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55 | this.not = not; |
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56 | nblks++; |
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57 | ID = nblks; |
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58 | } |
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59 | |
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60 | public void addAlternative(Alternative alt) { |
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61 | alternatives.appendElement(alt); |
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62 | } |
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63 | |
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64 | public void generate() { |
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65 | grammar.generator.gen(this); |
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66 | } |
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67 | |
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68 | public Alternative getAlternativeAt(int i) { |
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69 | return (Alternative)alternatives.elementAt(i); |
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70 | } |
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71 | |
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72 | public Vector getAlternatives() { |
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73 | return alternatives; |
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74 | } |
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75 | |
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76 | public boolean getAutoGen() { |
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77 | return doAutoGen; |
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78 | } |
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79 | |
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80 | public String getInitAction() { |
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81 | return initAction; |
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82 | } |
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83 | |
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84 | public String getLabel() { |
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85 | return label; |
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86 | } |
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87 | |
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88 | public Lookahead look(int k) { |
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89 | return grammar.theLLkAnalyzer.look(k, this); |
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90 | } |
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91 | |
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92 | public void prepareForAnalysis() { |
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93 | for (int i = 0; i < alternatives.size(); i++) { |
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94 | // deterministic() uses an alternative cache and sets lookahead depth |
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95 | Alternative a = (Alternative)alternatives.elementAt(i); |
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96 | a.cache = new Lookahead[grammar.maxk + 1]; |
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97 | a.lookaheadDepth = GrammarAnalyzer.LOOKAHEAD_DEPTH_INIT; |
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98 | } |
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99 | } |
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100 | |
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101 | /**Walk the syntactic predicate and, for a rule ref R, remove |
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102 | * the ref from the list of FOLLOW references for R (stored |
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103 | * in the symbol table. |
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104 | */ |
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105 | public void removeTrackingOfRuleRefs(Grammar g) { |
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106 | for (int i = 0; i < alternatives.size(); i++) { |
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107 | Alternative alt = getAlternativeAt(i); |
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108 | AlternativeElement elem = alt.head; |
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109 | while (elem != null) { |
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110 | if (elem instanceof RuleRefElement) { |
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111 | RuleRefElement rr = (RuleRefElement)elem; |
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112 | RuleSymbol rs = (RuleSymbol)g.getSymbol(rr.targetRule); |
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113 | if (rs == null) { |
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114 | grammar.antlrTool.error("rule " + rr.targetRule + " referenced in (...)=>, but not defined"); |
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115 | } |
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116 | else { |
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117 | rs.references.removeElement(rr); |
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118 | } |
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119 | } |
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120 | else if (elem instanceof AlternativeBlock) {// recurse into subrules |
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121 | ((AlternativeBlock)elem).removeTrackingOfRuleRefs(g); |
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122 | } |
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123 | elem = elem.next; |
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124 | } |
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125 | } |
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126 | } |
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127 | |
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128 | public void setAlternatives(Vector v) { |
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129 | alternatives = v; |
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130 | } |
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131 | |
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132 | public void setAutoGen(boolean doAutoGen_) { |
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133 | doAutoGen = doAutoGen_; |
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134 | } |
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135 | |
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136 | public void setInitAction(String initAction_) { |
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137 | initAction = initAction_; |
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138 | } |
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139 | |
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140 | public void setLabel(String label_) { |
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141 | label = label_; |
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142 | } |
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143 | |
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144 | public void setOption(Token key, Token value) { |
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145 | if (key.getText().equals("warnWhenFollowAmbig")) { |
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146 | if (value.getText().equals("true")) { |
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147 | warnWhenFollowAmbig = true; |
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148 | } |
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149 | else if (value.getText().equals("false")) { |
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150 | warnWhenFollowAmbig = false; |
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151 | } |
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152 | else { |
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153 | grammar.antlrTool.error("Value for warnWhenFollowAmbig must be true or false", grammar.getFilename(), key.getLine(), key.getColumn()); |
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154 | } |
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155 | } |
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156 | else if (key.getText().equals("generateAmbigWarnings")) { |
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157 | if (value.getText().equals("true")) { |
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158 | generateAmbigWarnings = true; |
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159 | } |
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160 | else if (value.getText().equals("false")) { |
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161 | generateAmbigWarnings = false; |
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162 | } |
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163 | else { |
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164 | grammar.antlrTool.error("Value for generateAmbigWarnings must be true or false", grammar.getFilename(), key.getLine(), key.getColumn()); |
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165 | } |
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166 | } |
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167 | else if (key.getText().equals("greedy")) { |
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168 | if (value.getText().equals("true")) { |
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169 | greedy = true; |
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170 | greedySet = true; |
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171 | } |
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172 | else if (value.getText().equals("false")) { |
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173 | greedy = false; |
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174 | greedySet = true; |
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175 | } |
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176 | else { |
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177 | grammar.antlrTool.error("Value for greedy must be true or false", grammar.getFilename(), key.getLine(), key.getColumn()); |
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178 | } |
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179 | } |
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180 | else { |
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181 | grammar.antlrTool.error("Invalid subrule option: " + key.getText(), grammar.getFilename(), key.getLine(), key.getColumn()); |
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182 | } |
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183 | } |
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184 | |
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185 | public String toString() { |
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186 | String s = " ("; |
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187 | if (initAction != null) { |
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188 | s += initAction; |
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189 | } |
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190 | for (int i = 0; i < alternatives.size(); i++) { |
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191 | Alternative alt = getAlternativeAt(i); |
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192 | Lookahead cache[] = alt.cache; |
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193 | int k = alt.lookaheadDepth; |
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194 | // dump lookahead set |
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195 | if (k == GrammarAnalyzer.LOOKAHEAD_DEPTH_INIT) { |
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196 | } |
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197 | else if (k == GrammarAnalyzer.NONDETERMINISTIC) { |
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198 | s += "{?}:"; |
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199 | } |
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200 | else { |
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201 | s += " {"; |
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202 | for (int j = 1; j <= k; j++) { |
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203 | s += cache[j].toString(",", grammar.tokenManager.getVocabulary()); |
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204 | if (j < k && cache[j + 1] != null) s += ";"; |
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205 | } |
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206 | s += "}:"; |
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207 | } |
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208 | // dump alternative including pred (if any) |
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209 | AlternativeElement p = alt.head; |
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210 | String pred = alt.semPred; |
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211 | if (pred != null) { |
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212 | s += pred; |
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213 | } |
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214 | while (p != null) { |
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215 | s += p; |
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216 | p = p.next; |
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217 | } |
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218 | if (i < (alternatives.size() - 1)) { |
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219 | s += " |"; |
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220 | } |
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221 | } |
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222 | s += " )"; |
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223 | return s; |
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224 | } |
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225 | |
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226 | } |
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