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1 /* |
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2 * Copyright (c) 2004-2008 Nokia Corporation and/or its subsidiary(-ies). |
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3 * All rights reserved. |
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4 * This component and the accompanying materials are made available |
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5 * under the terms of "Eclipse Public License v1.0" |
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6 * which accompanies this distribution, and is available |
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7 * at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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8 * |
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9 * Initial Contributors: |
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10 * Nokia Corporation - initial contribution. |
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11 * |
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12 * Contributors: |
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13 * |
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14 * Description: |
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15 * |
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16 */ |
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17 |
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18 using System; |
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19 using System.Text; |
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20 using System.Collections; |
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21 using SymBuildParsingLib.Tree; |
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22 using SymbianTree; |
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23 |
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24 namespace SymBuildParsingLib.Token |
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25 { |
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26 public class SymTokenBalancer |
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27 { |
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28 #region Observer interface |
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29 public delegate void LevelsBalancedEventHandler(); |
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30 public delegate void LevelsImbalancedEventHandler(); |
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31 public delegate void LevelChangeEventHandler( int aLevelCount, SymNode aOldLevel, SymNode aNewLevel ); |
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32 #endregion |
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33 |
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34 #region Events |
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35 public event LevelChangeEventHandler EventLevelStarted; |
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36 public event LevelChangeEventHandler EventLevelFinished; |
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37 public event LevelsBalancedEventHandler EventLevelsBalanced; |
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38 public event LevelsImbalancedEventHandler EventLevelsImbalanced; |
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39 #endregion |
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40 |
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41 #region Constructors & destructor |
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42 public SymTokenBalancer() |
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43 { |
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44 Reset(); |
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45 System.Diagnostics.Debug.IndentSize = 1; |
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46 } |
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47 #endregion |
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48 |
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49 #region API |
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50 public void RegisterBalancerTokens() |
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51 { |
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52 RegisterBalancerTokens( false ); |
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53 } |
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54 |
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55 public virtual void RegisterBalancerTokens( bool aEmitLevelZeroBrackets ) |
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56 { |
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57 // These are the important tokens relating to function arguments |
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58 SymToken bracketTokenOpening = new SymToken( "(", SymToken.TClass.EClassSymbol, SymToken.TType.ETypeUnidentified ); |
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59 SymToken bracketTokenClosing = new SymToken( ")", SymToken.TClass.EClassSymbol, SymToken.TType.ETypeUnidentified ); |
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60 |
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61 // When parsing a function name and arguments, we want to start a new level when we see the first opening |
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62 // brace, but we don't want to emit the token. |
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63 RegisterOpeningToken( bracketTokenOpening, bracketTokenClosing, aEmitLevelZeroBrackets, true, TLevelExpectations.ELevelExpectationsAtLevel, 0, TAssociatedBehaviour.EBehaviourRemoveReduntantBracketing ); |
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64 RegisterClosingToken( bracketTokenClosing, bracketTokenOpening, aEmitLevelZeroBrackets, true, TLevelExpectations.ELevelExpectationsAtLevel, 0, TAssociatedBehaviour.EBehaviourRemoveReduntantBracketing ); |
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65 |
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66 // For other brackets, we want to reduce the complexity by removing any redundant entries |
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67 RegisterOpeningToken( bracketTokenOpening, bracketTokenClosing, true, true, TLevelExpectations.ELevelExpectationsAboveLevelNumber, 0, TAssociatedBehaviour.EBehaviourRemoveReduntantBracketing ); |
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68 RegisterClosingToken( bracketTokenClosing, bracketTokenOpening, true, true, TLevelExpectations.ELevelExpectationsAboveLevelNumber, 0, TAssociatedBehaviour.EBehaviourRemoveReduntantBracketing ); |
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69 } |
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70 |
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71 public virtual bool OfferToken( SymToken aToken ) |
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72 { |
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73 bool consumed = false; |
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74 int currentLevelNumber = CurrentLevelNumber; |
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75 SymTokenBalancerMatchCriteria tokenExtendedInfo; |
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76 |
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77 // Check for bracket matches |
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78 if ( IsOpeningTokenMatch( aToken, out tokenExtendedInfo, currentLevelNumber ) ) |
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79 { |
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80 LevelStarted( aToken, tokenExtendedInfo ); |
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81 consumed = true; |
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82 } |
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83 else if ( IsClosingTokenMatch( aToken, out tokenExtendedInfo, currentLevelNumber ) ) |
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84 { |
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85 LevelFinished( aToken, tokenExtendedInfo ); |
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86 consumed = true; |
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87 } |
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88 |
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89 // Always consume the token if it didn't match |
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90 if ( ! consumed ) |
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91 { |
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92 AddToCurrentLevel( aToken ); |
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93 consumed = true; |
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94 } |
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95 // |
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96 return consumed; |
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97 } |
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98 |
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99 public virtual void Reset() |
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100 { |
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101 iTree = new SymTokenBalancerDocument(); |
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102 } |
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103 #endregion |
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104 |
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105 #region API - registration |
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106 public void RegisterOpeningToken( SymToken aToken, SymToken aDiametricToken, bool aEmit, bool aStartsNewLevel, TLevelExpectations aLevelExpectations, int aAssociatedLevel, TAssociatedBehaviour aBehaviour ) |
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107 { |
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108 SymTokenBalancerMatchCriteria criteria = new SymTokenBalancerMatchCriteria( aDiametricToken, aEmit, aStartsNewLevel, aLevelExpectations, aAssociatedLevel, aBehaviour ); |
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109 RegisterOpeningToken( aToken, criteria ); |
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110 } |
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111 |
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112 public void RegisterOpeningToken( SymToken aToken, SymTokenBalancerMatchCriteria aCriteria ) |
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113 { |
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114 SymToken copy = new SymToken( aToken ); |
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115 copy.Tag = aCriteria; |
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116 // |
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117 if ( IsTokenExactMatch( copy, iOpeningTokens ) == false ) |
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118 { |
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119 iOpeningTokens.Append( copy ); |
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120 } |
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121 } |
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122 |
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123 public void RegisterClosingToken( SymToken aToken, SymToken aDiametricToken, bool aEmit, bool aStartsNewLevel, TLevelExpectations aLevelExpectations, int aAssociatedLevel, TAssociatedBehaviour aBehaviour ) |
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124 { |
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125 SymTokenBalancerMatchCriteria criteria = new SymTokenBalancerMatchCriteria( aDiametricToken, aEmit, aStartsNewLevel, aLevelExpectations, aAssociatedLevel, aBehaviour ); |
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126 RegisterClosingToken( aToken, criteria ); |
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127 } |
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128 |
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129 public void RegisterClosingToken( SymToken aToken, SymTokenBalancerMatchCriteria aCriteria ) |
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130 { |
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131 SymToken copy = new SymToken( aToken ); |
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132 copy.Tag = aCriteria; |
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133 // |
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134 if ( IsTokenExactMatch( copy, iClosingTokens ) == false ) |
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135 { |
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136 iClosingTokens.Append( copy ); |
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137 } |
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138 } |
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139 #endregion |
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140 |
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141 #region Properties - level related |
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142 public int CurrentLevelNumber |
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143 { |
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144 get |
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145 { |
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146 int depth = iTree.CurrentNode.Depth; |
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147 return depth; |
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148 } |
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149 } |
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150 |
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151 public SymNode CurrentNode |
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152 { |
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153 get { return iTree.CurrentNode; } |
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154 } |
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155 |
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156 public SymTokenBalancerDocument DocumentTree |
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157 { |
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158 get { return iTree; } |
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159 } |
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160 #endregion |
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161 |
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162 #region Notification framework |
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163 protected virtual void NotifyEventLevelStarted( int aLevelCount, SymNode aOldLevel, SymNode aNewLevel ) |
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164 { |
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165 if ( EventLevelStarted != null ) |
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166 { |
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167 EventLevelStarted( aLevelCount, aOldLevel, aNewLevel ); |
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168 } |
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169 } |
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170 |
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171 protected virtual void NotifyEventLevelFinished( int aLevelCount, SymNode aOldLevel, SymNode aNewLevel ) |
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172 { |
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173 if ( EventLevelFinished != null ) |
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174 { |
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175 EventLevelFinished( aLevelCount, aOldLevel, aNewLevel ); |
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176 } |
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177 } |
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178 |
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179 protected virtual void NotifyEventLevelsImbalanced() |
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180 { |
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181 if ( EventLevelsImbalanced != null ) |
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182 { |
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183 EventLevelsImbalanced(); |
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184 } |
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185 } |
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186 #endregion |
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187 |
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188 #region Utility methods |
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189 protected bool IsTokenExactMatch( SymToken aToken, SymTokenContainer aContainerToSearch ) |
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190 { |
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191 bool ret = false; |
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192 // |
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193 foreach( SymToken t in aContainerToSearch ) |
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194 { |
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195 if ( t.Equals( aToken ) ) |
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196 { |
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197 if ( aToken.Tag != null && t.Tag != null ) |
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198 { |
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199 if ( ( aToken.Tag is SymTokenBalancerMatchCriteria ) && ( t.Tag is SymTokenBalancerMatchCriteria ) ) |
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200 { |
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201 SymTokenBalancerMatchCriteria extendedInfo1 = (SymTokenBalancerMatchCriteria) aToken.Tag; |
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202 SymTokenBalancerMatchCriteria extendedInfo2 = (SymTokenBalancerMatchCriteria) t.Tag; |
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203 // |
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204 if ( extendedInfo1.Equals( extendedInfo2 ) ) |
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205 { |
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206 ret = true; |
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207 break; |
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208 } |
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209 } |
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210 } |
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211 } |
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212 } |
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213 // |
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214 return ret; |
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215 } |
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216 |
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217 protected bool IsOpeningTokenMatch( SymToken aToken, out SymTokenBalancerMatchCriteria aCriteria, int aLevelNumber ) |
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218 { |
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219 aCriteria = null; |
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220 bool matchFound = false; |
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221 // |
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222 int index = iOpeningTokens.IndexOf( aToken ); |
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223 while( index >= 0 && matchFound == false ) |
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224 { |
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225 SymToken token = iOpeningTokens[ index ]; |
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226 System.Diagnostics.Debug.Assert ( token.Tag != null && token.Tag is SymTokenBalancerMatchCriteria ); |
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227 SymTokenBalancerMatchCriteria criteria = (SymTokenBalancerMatchCriteria) token.Tag; |
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228 |
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229 if ( criteria.Matches( aLevelNumber ) ) |
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230 { |
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231 aCriteria = criteria; |
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232 matchFound = true; |
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233 } |
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234 else |
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235 { |
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236 index = iOpeningTokens.IndexOf( aToken, index+1 ); |
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237 } |
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238 } |
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239 |
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240 return matchFound; |
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241 } |
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242 |
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243 protected bool IsClosingTokenMatch( SymToken aToken, out SymTokenBalancerMatchCriteria aCriteria, int aLevelNumber ) |
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244 { |
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245 aCriteria = null; |
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246 bool matchFound = false; |
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247 // |
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248 int index = iClosingTokens.IndexOf( aToken ); |
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249 while( index >= 0 && matchFound == false ) |
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250 { |
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251 SymToken token = iClosingTokens[ index ]; |
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252 System.Diagnostics.Debug.Assert ( token.Tag != null && token.Tag is SymTokenBalancerMatchCriteria ); |
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253 SymTokenBalancerMatchCriteria criteria = (SymTokenBalancerMatchCriteria) token.Tag; |
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254 |
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255 if ( criteria.Matches( aLevelNumber ) ) |
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256 { |
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257 aCriteria = criteria; |
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258 matchFound = true; |
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259 } |
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260 else |
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261 { |
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262 index = iClosingTokens.IndexOf( aToken, index+1 ); |
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263 } |
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264 } |
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265 |
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266 return matchFound; |
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267 } |
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268 |
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269 protected static int CountTokenByType( SymNode aNodeWithChildren, SymToken.TClass aClass ) |
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270 { |
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271 int count = 0; |
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272 // |
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273 foreach( SymNode n in aNodeWithChildren ) |
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274 { |
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275 bool isNodeToken = ( n is SymNodeToken ); |
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276 // |
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277 if ( isNodeToken ) |
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278 { |
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279 bool isSpecial = ( ( n is SymTokenBalancerNode ) || ( n is SymTokenBalancerNodeEmittedElement ) ); |
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280 // |
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281 if ( isSpecial == false ) |
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282 { |
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283 SymToken t = ((SymNodeToken) n).Token; |
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284 // |
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285 if ( t.Class == aClass ) |
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286 { |
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287 ++count; |
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288 } |
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289 } |
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290 } |
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291 } |
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292 // |
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293 return count; |
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294 } |
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295 |
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296 protected bool LevelCanBeMergedWithParent( SymTokenBalancerMarkerLevelNode aLevelNode ) |
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297 { |
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298 #region Example |
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299 // We can replace the opening bracket, the level marker and the closing bracket |
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300 // with the level marker's child. |
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301 // |
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302 // E.g. |
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303 // ( = opening bracket |
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304 // * = level marker |
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305 // ) = closing bracket |
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306 // V = 'real' node value |
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307 // |
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308 // This: |
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309 // |
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310 // ( -- * -- ) |
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311 // | |
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312 // V |
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313 // |
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314 // Can become: |
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315 // |
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316 // V |
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317 // |
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318 // |
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319 // Or this: |
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320 // |
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321 // ( -- * -- ) |
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322 // | |
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323 // [ -- * -- ] |
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324 // | |
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325 // V |
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326 // |
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327 // Can become: |
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328 // |
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329 // [ -- * -- ] |
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330 // | |
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331 // V |
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332 // |
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333 #endregion |
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334 System.Diagnostics.Debug.Assert( aLevelNode.HasPrevious && aLevelNode.HasNext ); |
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335 System.Diagnostics.Debug.Assert( aLevelNode.Previous is SymTokenBalancerNodeEmittedElement && aLevelNode.Next is SymTokenBalancerNodeEmittedElement ); |
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336 // |
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337 bool ret = false; |
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338 // |
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339 SymTokenBalancerNodeEmittedElement previous = (SymTokenBalancerNodeEmittedElement) aLevelNode.Previous; |
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340 SymTokenBalancerNodeEmittedElement next = (SymTokenBalancerNodeEmittedElement) aLevelNode.Next; |
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341 |
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342 // We should be able to remove these brackets, providing they are diametrically oposites. |
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343 SymTokenBalancerMatchCriteria matchInfo; |
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344 if ( IsOpeningTokenMatch( previous.Token, out matchInfo, CurrentLevelNumber ) ) |
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345 { |
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346 // We've now got the match info for this opening token. We can compare the |
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347 // match info's diametric token against the closing token to check that they |
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348 // really are equal and oposite. |
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349 if ( matchInfo.DiametricToken.Equals( next.Token ) ) |
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350 { |
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351 // Check whether the children are suitable for coalescing |
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352 int grandChildCount = aLevelNode.ChildCount; |
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353 int numberOfWhiteSpaceGrandChildren = CountTokenByType( aLevelNode, SymToken.TClass.EClassWhiteSpace ); |
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354 int nonWhiteSpaceGrandChildrenCount = grandChildCount - numberOfWhiteSpaceGrandChildren; |
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355 |
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356 if ( nonWhiteSpaceGrandChildrenCount == 1 ) |
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357 { |
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358 // If there is just a single non-whitespace token then we are able to |
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359 // coalesce this branch |
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360 ret = true; |
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361 } |
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362 else if ( nonWhiteSpaceGrandChildrenCount == 3 ) |
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363 { |
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364 // Branch contains several non-whitespace children. Must check further |
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365 // to see if they are simply bracketed regions themselves |
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366 object levelObject = aLevelNode.ChildByType( typeof( SymTokenBalancerMarkerLevelNode ) ); |
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367 if ( levelObject != null ) |
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368 { |
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369 SymTokenBalancerMarkerLevelNode childLevel = (SymTokenBalancerMarkerLevelNode) levelObject; |
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370 // |
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371 if ( childLevel.HasPrevious && childLevel.HasNext ) |
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372 { |
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373 ret = ( childLevel.Previous is SymTokenBalancerNodeEmittedElement && childLevel.Next is SymTokenBalancerNodeEmittedElement ); |
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374 } |
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375 } |
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376 else |
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377 { |
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378 ret = true; |
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379 } |
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380 } |
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381 } |
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382 } |
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383 // |
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384 return ret; |
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385 } |
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386 |
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387 protected void SimplifyLevel( SymTokenBalancerMarkerLevelNode aLevel ) |
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388 { |
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389 System.Diagnostics.Debug.Assert( aLevel.IsRoot == false && aLevel.HasParent ); |
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390 SymNode parent = aLevel.Parent; |
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391 int levelNumber = parent.Depth; |
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392 // |
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393 int childCount = parent.ChildCount; |
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394 while( --childCount >= 0 ) |
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395 { |
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396 SymNode possibleLevelNode = parent[ childCount ]; |
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397 |
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398 // We're looking to remove redundant bracketing from either side of the level |
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399 // node. First check if we have a level node... |
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400 if ( possibleLevelNode is SymTokenBalancerMarkerLevelNode ) |
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401 { |
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402 // Then check whether it has a previous and a next node. These should |
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403 // be the SymTokenBalancerNodeEmittedElement nodes |
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404 if ( possibleLevelNode.HasPrevious && possibleLevelNode.HasNext ) |
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405 { |
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406 if ( possibleLevelNode.Previous is SymTokenBalancerNodeEmittedElement && possibleLevelNode.Next is SymTokenBalancerNodeEmittedElement ) |
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407 { |
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408 if ( LevelCanBeMergedWithParent( possibleLevelNode as SymTokenBalancerMarkerLevelNode ) ) |
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409 { |
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410 SymTokenBalancerNodeEmittedElement previous = (SymTokenBalancerNodeEmittedElement) possibleLevelNode.Previous; |
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411 SymTokenBalancerNodeEmittedElement next = (SymTokenBalancerNodeEmittedElement) possibleLevelNode.Next; |
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412 |
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413 // Insert value node prior to previous node (which is the opening bracket token). |
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414 parent.InsertChildrenFrom( possibleLevelNode, previous.Previous ); |
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415 |
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416 // Remove the opening bracket token |
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417 previous.Remove(); |
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418 |
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419 // Remove the level marker token |
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420 possibleLevelNode.Remove(); |
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421 |
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422 // Remove the closing bracket token. |
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423 next.Remove(); |
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424 } |
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425 } |
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426 } |
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427 } |
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428 } |
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429 } |
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430 #endregion |
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431 |
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432 #region Internal level manipulation methods |
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433 protected virtual void LevelStarted( SymToken aToken, SymTokenBalancerMatchCriteria aMatchCriteria ) |
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434 { |
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435 System.Diagnostics.Debug.Write( System.Environment.NewLine + aToken.Value ); |
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436 |
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437 // Always store the node element so that we can balance brackets |
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438 SymTokenBalancerNodeEmittedElement node = new SymTokenBalancerNodeEmittedElement( aToken, aMatchCriteria ); |
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439 iTree.CurrentNode.Add( node ); |
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440 |
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441 // Store the token (with the level) so we can check for open/close mis-matches |
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442 SymTokenBalancerMarkerLevelNode levelNode = new SymTokenBalancerMarkerLevelNode( aMatchCriteria ); |
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443 iTree.CurrentNode.Add( levelNode ); |
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444 |
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445 SymNode oldLevel = iTree.CurrentNode; |
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446 SymNode newLevel = levelNode; |
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447 NotifyEventLevelStarted( CurrentLevelNumber, oldLevel, newLevel ); |
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448 |
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449 iTree.CurrentNode = levelNode; |
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450 } |
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451 |
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452 protected virtual void LevelFinished( SymToken aToken, SymTokenBalancerMatchCriteria aMatchCriteria ) |
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453 { |
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454 #region Example |
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455 |
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456 // #define TEST1((( B )+( C ))+(E)) |
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457 |
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458 #region Key |
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459 // |y| = level y |
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460 // [x] = token of value 'x' |
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461 // [*] = level marker node |
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462 // [@] = (current) level marker node |
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463 // [,] = argument node |
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464 // [(] = opening level emitted token node |
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465 // [)] = closing level emitted token node |
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466 #endregion |
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467 |
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468 #region 1) First wave of opening level tokens processed... |
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469 // |
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470 // |0| [ROOT] |
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471 // | |
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472 // |1| [TEST] [(] [*] |
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473 // | |
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474 // |2| [(] [*] |
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475 // | |
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476 // |3| [(] [@] |
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477 // | |
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478 // |4| B |
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479 // |
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480 #endregion |
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481 |
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482 #region 2) Add closing level token to level |3|, which means that we can now |
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483 // attempt to simplify level |4|. Level |4| does not contain any child |
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484 // level nodes, so there is nothing to do here. |
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485 // |
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486 // |0| [ROOT] |
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487 // | |
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488 // |1| [TEST] [(] [*] |
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489 // | |
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490 // |2| [(] [@] |
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491 // | |
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492 // |3| [(] [*] [)] |
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493 // | |
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494 // |4| [ ] [B] [ ] |
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495 // |
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496 #endregion |
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497 |
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498 #region 3) Add plus symbol. This obviously becomes a child of the current node, |
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499 // i.e. a child of level |2|. |
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500 // |
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501 // |0| [ROOT] |
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502 // | |
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503 // |1| [TEST] [(] [*] |
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504 // | |
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505 // |2| [(] [@] |
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506 // | |
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507 // |3| [(] [*] [)] [+] |
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508 // | |
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509 // |4| [ ] [B] [ ] |
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510 // |
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511 #endregion |
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512 |
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513 #region 4) Start new opening level node on level |3|. The newly added level node |
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514 // on level |3| becomes the current node. |
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515 // |
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516 // |0| [ROOT] |
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517 // | |
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518 // |1| [TEST] [(] [*] |
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519 // | |
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520 // |2| [(] [*] |
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521 // | |
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522 // |3| [(] [*] [)] [+] [(] [@] |
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523 // | | |
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524 // |4| [ ] [B] [ ] |
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525 // |
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526 #endregion |
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527 |
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528 #region 5) Add the tokens near the 'C' to level |4| |
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529 // |
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530 // |0| [ROOT] |
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531 // | |
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532 // |1| [TEST] [(] [*] |
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533 // | |
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534 // |2| [(] [*] |
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535 // | |
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536 // |3| [(] [*] [)] [+] [(] [@] |
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537 // | | |
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538 // |4| [ ] [B] [ ] [ ] [C] [ ] |
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539 // |
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540 #endregion |
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541 |
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542 #region 6) Add closing level token to level |3|, which means that we can now |
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543 // attempt to simplify level |4|, this time the [C] branch. |
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544 // Since this branch does not contain any sub-level nodes, there is nothing |
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545 // to be done and therefore levels |3| and |4| remain unchanged. |
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546 // The level node at level |2| becomes the current node. |
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547 // |
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548 // |0| [ROOT] |
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549 // | |
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550 // |1| [TEST] [(] [*] |
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551 // | |
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552 // |2| [(] [@] |
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553 // | |
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554 // |3| [(] [*] [)] [+] [(] [*] [)] |
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555 // | | |
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556 // |4| [ ] [B] [ ] [ ] [C] [ ] |
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557 // |
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558 #endregion |
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559 |
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560 #region 7a) Add closing level token to level |2|, which means that we can now |
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561 // attempt to simplify level |3|. |
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562 // |
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563 // |0| [ROOT] |
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564 // | |
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565 // |1| [TEST] [(] [*] |
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566 // | |
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567 // |2| [(] [@] [)] |
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568 // | |
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569 // |3| [(] [*] [)] [+] [(] [*] [)] |
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570 // | | |
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571 // |4| [ ] [B] [ ] [ ] [C] [ ] |
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572 // |
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573 #endregion |
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574 |
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575 #region 7b) We iterate through all the child level nodes of level |3| looking |
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576 // to see if any of their children are simple enough to merge up into level |
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577 // |3| itself. There are two level nodes in level |3| and both contain |
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578 // children that are considered simple enough to merge up. This is because |
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579 // they contain only a single non-whitespace node so we can simplify the level by |
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580 // merging [B] from level |4| into level |3|. Likewise for [C]. |
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581 // |
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582 // This means that the bracketry on level |3| is redundant since level |
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583 // |4| contains two sets of only a single non-whitespace token. Level |4| |
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584 // is therefore entirely removed. |
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585 // |
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586 // The node at level |1| becomes the current node now. |
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587 // |
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588 // |0| [ROOT] |
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589 // | |
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590 // |1| [TEST] [(] [@] |
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591 // | |
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592 // |2| [(] [*] [)] |
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593 // | |
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594 // |3| [ ] [B] [ ] [+] [ ] [C] [ ] |
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595 // |
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596 #endregion |
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597 |
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598 #region 8) Add the plus symbol to level |2|. Then we start a new level |
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599 // as a result of adding the opening bracket prior to 'E.' |
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600 // This new level node at level |2| now becomes the current node. |
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601 // |
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602 // |0| [ROOT] |
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603 // | |
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604 // |1| [TEST] [(] [*] |
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605 // | |
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606 // |2| [(] [*] [)] [+] [(] [@] |
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607 // | | |
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608 // |3| [ ] [B] [ ] [+] [ ] [C] [ ] |
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609 // |
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610 #endregion |
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611 |
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612 #region 9) Now add the 'E' token to level |3|. |
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613 // |
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614 // |0| [ROOT] |
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615 // | |
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616 // |1| [TEST] [(] [*] |
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617 // | |
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618 // |2| [(] [*] [)] [+] [(] [@] |
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619 // | | |
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620 // |3| [ ] [B] [ ] [+] [ ] [C] [ ] [E] |
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621 #endregion |
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622 |
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623 #region 10) We then add the closing bracket to level |2| which means |
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624 // that we can attempt to simplify level |3|'s 'E' branch. There's nothing |
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625 // to do though, since it doesn't contain any child level nodes. |
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626 // The level node at level |1| again becomes current. |
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627 // |
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628 // |0| [ROOT] |
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629 // | |
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630 // |1| [TEST] [(] [@] |
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631 // | |
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632 // |2| [(] [*] [)] [+] [(] [*] [)] |
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633 // | | |
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634 // |3| [ ] [B] [ ] [+] [ ] [C] [ ] [E] |
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635 #endregion |
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636 |
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637 #region 11a) We then add the closing bracket to level |1| which means |
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638 // that we can attempt to simplify level |2| entirely. This is the |
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639 // situation prior to simplification. |
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640 // |
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641 // |0| [ROOT] |
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642 // | |
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643 // |1| [TEST] [(] [@] [)] |
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644 // | |
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645 // |2| [(] [*] [)] [+] [(] [*] [)] |
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646 // | | |
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647 // |3| [ ] [B] [ ] [+] [ ] [C] [ ] [E] |
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648 #endregion |
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649 |
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650 #region 11b) The two level nodes have been taged as *1 and *2 to make it |
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651 // easier to explain the process. First we attempt to simplify level *1. |
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652 // However, since its children consist of more than a single non-whitespace |
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653 // token, we cannot make level |3|'s " B + C " branch as a replacement |
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654 // for the bracket *1 tokens. Therefore this remains unchanged |
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655 // |
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656 // |
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657 // |0| [ROOT] |
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658 // | |
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659 // |1| [TEST] [(] [@] [)] |
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660 // | |
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661 // |2| [(] [*1] [)] [+] [(] [*2] [)] |
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662 // | | |
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663 // |3| [ ] [B] [ ] [+] [ ] [C] [ ] [E] |
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664 #endregion |
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665 |
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666 #region 11c) The level *2 node, however, contains only a single non-whitespace |
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667 // child token, so it can be simplified. The level *2 node is replaced by |
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668 // its child (E). |
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669 // |
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670 // The final tree looks like this, with the root as the current node once more: |
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671 // |
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672 // |
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673 // |0| [@ROOT@] |
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674 // | |
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675 // |1| [TEST] [(] [*] [)] |
|
676 // | |
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677 // |2| [(] [*] [)] [+] [E] |
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678 // | |
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679 // |3| [ ] [B] [ ] [+] [ ] [C] [ ] |
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680 #endregion |
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681 |
|
682 #endregion |
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683 |
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684 System.Diagnostics.Debug.Write( aToken.Value ); |
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685 System.Diagnostics.Debug.WriteLine( " " ); |
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686 |
|
687 // First of all, check if the current node has a parent. If we're at the root |
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688 // node and we see a closing token, then we've got an imbalanced stack. |
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689 if ( iTree.CurrentNode.IsRoot ) |
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690 { |
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691 NotifyEventLevelsImbalanced(); |
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692 } |
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693 else |
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694 { |
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695 // We expect the parent to be a level node |
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696 System.Diagnostics.Debug.Assert( iTree.CurrentNode is SymTokenBalancerMarkerLevelNode ); |
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697 |
|
698 // Notify that we're about to change levels |
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699 SymTokenBalancerMarkerLevelNode currentLevel = (SymTokenBalancerMarkerLevelNode) iTree.CurrentNode; |
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700 SymNode newLevel = currentLevel.Parent; |
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701 |
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702 // The new level should not be null in this case |
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703 System.Diagnostics.Debug.Assert( newLevel != null ); |
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704 |
|
705 // Check whether the closing token type is the same type as was used to start |
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706 // the level. E.g. for this case is "([ANDMORE)]" which has a mis-match |
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707 // between the opening and closing braces on each level. We can't simplify this |
|
708 // during the 'end level behaviour' stage. |
|
709 bool levelsBalanced = currentLevel.MatchCriteria.DiametricToken.Equals( aToken ); |
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710 |
|
711 // Switch levels |
|
712 iTree.CurrentNode = newLevel; |
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713 |
|
714 // We have to refetch up-to-date match info, since we've changed levels, and the match |
|
715 // info that was used to enter this method is associated with the previous level |
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716 // (not the new level number, which is now one less). |
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717 SymTokenBalancerMatchCriteria matchCriteria; |
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718 if ( IsClosingTokenMatch( aToken, out matchCriteria, CurrentLevelNumber ) == false ) |
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719 { |
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720 matchCriteria = aMatchCriteria; |
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721 } |
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722 |
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723 // Always store the node element so that we can balance brackets |
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724 SymTokenBalancerNodeEmittedElement node = new SymTokenBalancerNodeEmittedElement( aToken, matchCriteria ); |
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725 iTree.CurrentNode.Add( node ); |
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726 |
|
727 // We have finished the current level. E.g. see step 6. Need to simplify level |2|, where possible. |
|
728 PerformEndLevelBehaviour( currentLevel ); |
|
729 |
|
730 if ( levelsBalanced ) |
|
731 { |
|
732 // Notify that we've finished some level |
|
733 NotifyEventLevelFinished( CurrentLevelNumber, currentLevel, newLevel ); |
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734 } |
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735 else |
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736 { |
|
737 // Imbalance |
|
738 NotifyEventLevelsImbalanced(); |
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739 } |
|
740 } |
|
741 } |
|
742 |
|
743 protected virtual void AddToCurrentLevel( SymToken aToken ) |
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744 { |
|
745 System.Diagnostics.Debug.Write( aToken.Value ); |
|
746 |
|
747 SymNodeToken node = new SymNodeToken( aToken ); |
|
748 iTree.CurrentNode.Add( node ); |
|
749 } |
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750 |
|
751 #endregion |
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752 |
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753 #region End level behaviour related |
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754 protected void PerformEndLevelBehaviour( SymTokenBalancerMarkerLevelNode aLevel ) |
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755 { |
|
756 PerformEndLevelBehaviour( aLevel, aLevel.MatchCriteria ); |
|
757 } |
|
758 |
|
759 protected virtual void PerformEndLevelBehaviour( SymNode aLevel, SymTokenBalancerMatchCriteria aCriteria ) |
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760 { |
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761 #region Example step (11a) from LevelFinished method |
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762 // |
|
763 // We then add the closing bracket to level |1| which means |
|
764 // that we can attempt to simplify level |2| entirely. This is the |
|
765 // situation prior to simplification. |
|
766 // |
|
767 // |0| [ROOT] |
|
768 // | |
|
769 // |1| [TEST] [(] [@] [)] |
|
770 // | |
|
771 // |2| [(] [*] [)] [+] [(] [*] [)] |
|
772 // | | |
|
773 // |3| [ ] [B] [ ] [+] [ ] [C] [ ] [E] |
|
774 // |
|
775 // aLevel would be the @ node at level |1|. |
|
776 // |
|
777 // We remove redundant bracketing from our children, i.e. those on level |2|, not from our own level. |
|
778 // Our parent takes care of removing this level's redundant bracketing (when it's level is completed) |
|
779 // or then when an argument separator token is handled. |
|
780 // |
|
781 // We must iterate through level |1|'s children to find other level nodes. We check whether each |
|
782 // child level node can be simplified by checking its children (i.e. our grandchildren). |
|
783 // |
|
784 #endregion |
|
785 |
|
786 if ( aCriteria.IsAssociatedBehaviourRemoveRedundantBracketing ) |
|
787 { |
|
788 int index = 0; |
|
789 object childLevelNodeObject = aLevel.ChildByType( typeof(SymTokenBalancerMarkerLevelNode), ref index ); |
|
790 while( childLevelNodeObject != null ) |
|
791 { |
|
792 SymTokenBalancerMarkerLevelNode childLevelNode = (SymTokenBalancerMarkerLevelNode) childLevelNodeObject; |
|
793 if ( childLevelNode.CanBeSubsumed ) |
|
794 { |
|
795 childLevelNode.Subsume(); |
|
796 } |
|
797 |
|
798 // Try to find next level node |
|
799 ++index; |
|
800 childLevelNodeObject = aLevel.ChildByType( typeof(SymTokenBalancerMarkerLevelNode), ref index ); |
|
801 } |
|
802 } |
|
803 } |
|
804 #endregion |
|
805 |
|
806 #region Data members |
|
807 private SymTokenBalancerDocument iTree; |
|
808 private SymTokenContainer iOpeningTokens = new SymTokenContainer(); |
|
809 private SymTokenContainer iClosingTokens = new SymTokenContainer(); |
|
810 #endregion |
|
811 } |
|
812 } |