Complex classes like Expression often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Expression, and based on these observations, apply Extract Interface, too.
1 | <?php |
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20 | class Expression |
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21 | { |
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22 | /** |
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23 | * @var Context |
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24 | */ |
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25 | protected $context; |
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26 | |||
27 | /** |
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28 | * @var EventManager |
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29 | */ |
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30 | protected $eventManager; |
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31 | |||
32 | /** |
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33 | * @param Context $context |
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34 | */ |
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35 | 879 | public function __construct(Context $context, EventManager $eventManager) |
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40 | |||
41 | /** |
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42 | * @param $expr |
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43 | * @return ExpressionCompilerInterface|AbstractExpressionCompiler |
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44 | */ |
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45 | 867 | protected function factory($expr) |
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46 | { |
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47 | 867 | switch (get_class($expr)) { |
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48 | /** |
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49 | * Call(s) |
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50 | */ |
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51 | 867 | case Node\Expr\MethodCall::class: |
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52 | 2 | return new Expression\MethodCall(); |
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53 | 867 | case Node\Expr\FuncCall::class: |
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54 | 13 | return new Expression\FunctionCall(); |
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55 | 862 | case Node\Expr\StaticCall::class: |
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56 | 1 | return new Expression\StaticCall(); |
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57 | /** |
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58 | * Operators |
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59 | */ |
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60 | 861 | case Node\Expr\New_::class: |
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61 | 6 | return new Expression\Operators\NewOp(); |
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62 | 861 | case Node\Expr\Instanceof_::class: |
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63 | return new Expression\Operators\InstanceOfOp(); |
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64 | /** |
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65 | * AssignOp |
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66 | */ |
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67 | 861 | case Node\Expr\AssignOp\Pow::class: |
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68 | 21 | return new Expression\AssignOp\Pow(); |
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69 | 840 | case Node\Expr\AssignOp\Plus::class: |
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70 | 17 | return new Expression\AssignOp\Plus(); |
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71 | 823 | case Node\Expr\AssignOp\Minus::class: |
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72 | 20 | return new Expression\AssignOp\Minus(); |
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73 | 803 | case Node\Expr\AssignOp\Mul::class: |
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74 | 20 | return new Expression\AssignOp\Mul(); |
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75 | 783 | case Node\Expr\AssignOp\Div::class: |
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76 | 20 | return new Expression\AssignOp\Div(); |
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77 | 765 | case Node\Expr\AssignOp\Mod::class: |
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78 | 13 | return new Expression\AssignOp\Mod(); |
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79 | 754 | case Node\Expr\AssignOp\BitwiseOr::class: |
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80 | 12 | return new Expression\AssignOp\BitwiseOr(); |
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81 | 742 | case Node\Expr\AssignOp\BitwiseAnd::class: |
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82 | 12 | return new Expression\AssignOp\BitwiseAnd(); |
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83 | 730 | case Node\Expr\AssignOp\BitwiseXor::class: |
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84 | 12 | return new Expression\AssignOp\BitwiseXor(); |
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85 | 718 | case Node\Expr\AssignOp\Concat::class: |
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86 | 14 | return new Expression\AssignOp\Concat(); |
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87 | 704 | case Node\Expr\AssignOp\ShiftLeft::class: |
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88 | 12 | return new Expression\AssignOp\ShiftLeft(); |
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89 | 692 | case Node\Expr\AssignOp\ShiftRight::class: |
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90 | 12 | return new Expression\AssignOp\ShiftRight(); |
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91 | |||
92 | /** |
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93 | * BinaryOp |
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94 | */ |
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95 | 680 | case Node\Expr\BinaryOp\Identical::class: |
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96 | 30 | return new Expression\BinaryOp\Identical(); |
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97 | 652 | case Node\Expr\BinaryOp\Concat::class: |
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98 | 14 | return new Expression\Operators\Concat(); |
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99 | 638 | case Node\Expr\BinaryOp\NotIdentical::class: |
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100 | 16 | return new Expression\BinaryOp\NotIdentical(); |
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101 | 624 | case Node\Expr\BinaryOp\Equal::class: |
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102 | 46 | return new Expression\BinaryOp\Equal(); |
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103 | 595 | case Node\Expr\BinaryOp\NotEqual::class: |
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104 | 19 | return new Expression\BinaryOp\NotEqual(); |
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105 | 578 | case Node\Expr\BinaryOp\Spaceship::class: |
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106 | 11 | return new Expression\BinaryOp\SpaceShip(); |
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107 | 569 | case Node\Expr\BinaryOp\Coalesce::class: |
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108 | return new Expression\BinaryOp\Coalesce(); |
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109 | |||
110 | /** |
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111 | * @link http://php.net/manual/en/language.operators.increment.php |
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112 | */ |
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113 | 569 | case Node\Expr\PostInc::class: |
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114 | 11 | return new Expression\Operators\PostInc(); |
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115 | 561 | case Node\Expr\PostDec::class: |
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116 | 8 | return new Expression\Operators\PostDec(); |
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117 | 553 | case Node\Expr\PreInc::class: |
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118 | 10 | return new Expression\Operators\PreInc(); |
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119 | 545 | case Node\Expr\PreDec::class: |
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120 | 9 | return new Expression\Operators\PreDec(); |
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121 | /** |
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122 | * Arithmetical |
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123 | */ |
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124 | 537 | case Node\Expr\BinaryOp\Div::class: |
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125 | 39 | return new Expression\Operators\Arithmetical\Div(); |
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126 | 500 | case Node\Expr\BinaryOp\Plus::class: |
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127 | 45 | return new Expression\Operators\Arithmetical\Plus(); |
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128 | 459 | case Node\Expr\BinaryOp\Minus::class: |
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129 | 24 | return new Expression\Operators\Arithmetical\Minus(); |
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130 | 435 | case Node\Expr\BinaryOp\Mul::class: |
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131 | 37 | return new Expression\Operators\Arithmetical\Mul(); |
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132 | 400 | case Node\Expr\BinaryOp\Mod::class: |
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133 | 38 | return new Expression\Operators\Arithmetical\Mod(); |
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134 | 365 | case Node\Expr\BinaryOp\Pow::class: |
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135 | 21 | return new Expression\Operators\Arithmetical\Pow(); |
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136 | |||
137 | /** |
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138 | * Bitwise |
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139 | * @link http://php.net/manual/ru/language.operators.bitwise.php |
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140 | */ |
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141 | 344 | case Node\Expr\BinaryOp\BitwiseOr::class: |
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142 | 12 | return new Expression\Operators\Bitwise\BitwiseOr(); |
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143 | 332 | case Node\Expr\BinaryOp\BitwiseXor::class: |
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144 | 12 | return new Expression\Operators\Bitwise\BitwiseXor(); |
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145 | 320 | case Node\Expr\BinaryOp\BitwiseAnd::class: |
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146 | 12 | return new Expression\Operators\Bitwise\BitwiseAnd(); |
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147 | 308 | case Node\Expr\BinaryOp\ShiftRight::class: |
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148 | 12 | return new Expression\Operators\Bitwise\ShiftRight(); |
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149 | 296 | case Node\Expr\BinaryOp\ShiftLeft::class: |
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150 | 12 | return new Expression\Operators\Bitwise\ShiftLeft(); |
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151 | 284 | case Node\Expr\BitwiseNot::class: |
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152 | 6 | return new Expression\Operators\Bitwise\BitwiseNot(); |
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153 | /** |
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154 | * Logical |
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155 | */ |
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156 | 279 | case Node\Expr\BinaryOp\BooleanOr::class: |
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157 | 17 | return new Expression\Operators\Logical\BooleanOr(); |
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158 | 264 | case Node\Expr\BinaryOp\BooleanAnd::class: |
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159 | 16 | return new Expression\Operators\Logical\BooleanAnd(); |
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160 | 251 | case Node\Expr\BooleanNot::class: |
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161 | 12 | return new Expression\Operators\Logical\BooleanNot(); |
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162 | 243 | case Node\Expr\BinaryOp\LogicalAnd::class: |
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163 | 15 | return new Expression\Operators\Logical\LogicalAnd(); |
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164 | 230 | case Node\Expr\BinaryOp\LogicalOr::class: |
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165 | 17 | return new Expression\Operators\Logical\LogicalOr(); |
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166 | 215 | case Node\Expr\BinaryOp\LogicalXor::class: |
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167 | 17 | return new Expression\Operators\Logical\LogicalXor(); |
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168 | |||
169 | /** |
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170 | * Comparison |
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171 | */ |
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172 | 200 | case Node\Expr\BinaryOp\Greater::class: |
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173 | 14 | return new Expression\Operators\Comparison\Greater(); |
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174 | 188 | case Node\Expr\BinaryOp\GreaterOrEqual::class: |
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175 | 13 | return new Expression\Operators\Comparison\GreaterOrEqual(); |
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176 | 176 | case Node\Expr\BinaryOp\Smaller::class: |
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177 | 15 | return new Expression\Operators\Comparison\Smaller(); |
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178 | 164 | case Node\Expr\BinaryOp\SmallerOrEqual::class: |
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179 | 13 | return new Expression\Operators\Comparison\SmallerOrEqual(); |
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180 | |||
181 | /** |
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182 | * Casts |
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183 | */ |
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184 | 152 | case Node\Expr\Cast\Array_::class: |
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185 | 3 | return new Expression\Casts\ArrayCast(); |
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186 | 151 | case Node\Expr\Cast\Bool_::class: |
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187 | 8 | return new Expression\Casts\BoolCast(); |
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188 | 145 | case Node\Expr\Cast\Int_::class: |
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189 | 8 | return new Expression\Casts\IntCast(); |
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190 | 139 | case Node\Expr\Cast\Double::class: |
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191 | 8 | return new Expression\Casts\DoubleCast(); |
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192 | 133 | case Node\Expr\Cast\Object_::class: |
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193 | 11 | return new Expression\Casts\ObjectCast(); |
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194 | 123 | case Node\Expr\Cast\String_::class: |
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195 | 7 | return new Expression\Casts\StringCast(); |
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196 | 117 | case Node\Expr\Cast\Unset_::class: |
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197 | 2 | return new Expression\Casts\UnsetCast(); |
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198 | |||
199 | |||
200 | /** |
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201 | * Other |
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202 | */ |
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203 | 116 | case Node\Expr\Array_::class: |
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204 | 43 | return new Expression\ArrayOp(); |
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205 | 87 | case Node\Expr\Assign::class: |
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206 | 43 | return new Expression\Assign(); |
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207 | 67 | case Node\Expr\AssignRef::class: |
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208 | 2 | return new Expression\AssignRef(); |
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209 | 67 | case Node\Expr\Closure::class: |
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210 | 1 | return new Expression\Closure(); |
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211 | 67 | case Node\Expr\ConstFetch::class: |
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212 | 15 | return new Expression\ConstFetch(); |
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213 | 60 | case Node\Expr\ClassConstFetch::class: |
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214 | return new Expression\ClassConstFetch(); |
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215 | 60 | case Node\Expr\PropertyFetch::class: |
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216 | return new Expression\PropertyFetch(); |
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217 | 60 | case Node\Expr\StaticPropertyFetch::class: |
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218 | return new Expression\StaticPropertyFetch(); |
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219 | 60 | case Node\Expr\ArrayDimFetch::class: |
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220 | return new Expression\ArrayDimFetch(); |
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221 | 60 | case Node\Expr\UnaryMinus::class: |
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222 | 10 | return new Expression\Operators\UnaryMinus(); |
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223 | 51 | case Node\Expr\UnaryPlus::class: |
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224 | 11 | return new Expression\Operators\UnaryPlus(); |
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225 | 40 | case Node\Expr\Exit_::class: |
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226 | 2 | return new Expression\ExitOp(); |
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227 | 38 | case Node\Expr\Isset_::class: |
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228 | return new Expression\IssetOp(); |
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229 | 38 | case Node\Expr\Print_::class: |
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230 | 2 | return new Expression\PrintOp(); |
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231 | 37 | case Node\Expr\Empty_::class: |
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232 | 5 | return new Expression\EmptyOp(); |
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233 | 32 | case Node\Expr\Eval_::class: |
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234 | 2 | return new Expression\EvalOp(); |
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235 | 30 | case Node\Expr\ShellExec::class: |
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236 | 1 | return new Expression\ShellExec(); |
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237 | 29 | case Node\Expr\ErrorSuppress::class: |
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238 | 2 | return new Expression\ErrorSuppress(); |
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239 | 27 | case Node\Expr\Include_::class: |
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240 | return new Expression\IncludeOp(); |
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241 | 27 | case Node\Expr\Clone_::class: |
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242 | 1 | return new Expression\CloneOp(); |
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243 | 26 | case Node\Expr\Ternary::class: |
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244 | 3 | return new Expression\Ternary(); |
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245 | 24 | case Node\Expr\Yield_::class: |
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246 | 1 | return new Expression\YieldOp(); |
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247 | 24 | case Node\Expr\YieldFrom::class: |
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248 | 1 | return new Expression\YieldFrom(); |
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249 | 24 | case Node\Expr\Variable::class: |
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250 | 24 | return new Expression\Variable(); |
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251 | } |
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252 | |||
253 | return false; |
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254 | } |
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255 | |||
256 | /** |
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257 | * @param object|string $expr |
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258 | * @throws InvalidArgumentException when $expr is not string/object/null |
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259 | * @throws RuntimeException when compiler class does not return a CompiledExpression |
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260 | * @return CompiledExpression |
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261 | */ |
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262 | 879 | public function compile($expr) |
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263 | { |
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264 | 879 | if (is_string($expr)) { |
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265 | 35 | return new CompiledExpression(CompiledExpression::STRING, $expr); |
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266 | } |
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267 | |||
268 | 879 | if (is_null($expr)) { |
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269 | 12 | return new CompiledExpression(CompiledExpression::NULL); |
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270 | } |
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271 | |||
272 | 879 | if (!is_object($expr)) { |
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273 | throw new InvalidArgumentException('$expr must be string/object/null'); |
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274 | } |
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275 | |||
276 | 879 | if ($expr instanceof Node\Scalar) { |
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277 | 817 | $scalar = new \PHPSA\Compiler\Scalar($this->context, $this->eventManager); |
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278 | 817 | return $scalar->compile($expr); |
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279 | } |
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280 | |||
281 | 868 | $this->eventManager->fire( |
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282 | 868 | ExpressionBeforeCompile::EVENT_NAME, |
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283 | 868 | new ExpressionBeforeCompile( |
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284 | 868 | $expr, |
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285 | 868 | $this->context |
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286 | 868 | ) |
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287 | 868 | ); |
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288 | |||
289 | 868 | $className = get_class($expr); |
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290 | switch ($className) { |
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291 | 868 | case Node\Arg::class: |
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292 | /** |
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293 | * @todo Better compile |
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294 | */ |
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295 | 2 | return $this->compile($expr->value); |
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296 | |||
297 | /** |
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298 | * Names |
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299 | */ |
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300 | 868 | case Node\Name::class: |
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301 | 31 | return $this->getNodeName($expr); |
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302 | 867 | case Node\Name\FullyQualified::class: |
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303 | 6 | return $this->getFullyQualifiedNodeName($expr); |
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304 | } |
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305 | |||
306 | 867 | $expressionCompiler = $this->factory($expr); |
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307 | 867 | if (!$expressionCompiler) { |
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308 | $this->context->debug("Expression compiler is not implemented for {$className}"); |
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309 | return new CompiledExpression(CompiledExpression::UNIMPLEMENTED); |
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310 | } |
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311 | |||
312 | 867 | $result = $expressionCompiler->pass($expr, $this->context); |
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313 | 867 | if (!$result instanceof CompiledExpression) { |
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314 | throw new RuntimeException('Please return CompiledExpression from ' . get_class($expressionCompiler)); |
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315 | } |
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316 | |||
317 | 867 | return $result; |
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318 | } |
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319 | |||
320 | /** |
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321 | * @todo Implement - does not belong in this file |
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322 | * |
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323 | * @param Node\Stmt\Property $st |
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324 | public function passProperty(Node\Stmt\Property $st) |
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325 | { |
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326 | $docBlock = $st->getDocComment(); |
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327 | if (!$docBlock) { |
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328 | return new CompiledExpression(); |
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329 | } |
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330 | |||
331 | $phpdoc = DocBlockFactory::createInstance()->create($docBlock->getText()); |
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332 | |||
333 | $varTags = $phpdoc->getTagsByName('var'); |
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334 | if ($varTags) { |
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335 | $varTag = current($varTags); |
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336 | |||
337 | $typeResolver = new \phpDocumentor\Reflection\TypeResolver(); |
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338 | |||
339 | try { |
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340 | $type = $typeResolver->resolve($varTag->getType()); |
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341 | } catch (\InvalidArgumentException $e) { |
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342 | return new CompiledExpression(); |
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343 | } |
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344 | |||
345 | if ($type) { |
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346 | switch (get_class($type)) { |
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347 | case \phpDocumentor\Reflection\Types\Object_::class: |
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348 | return new CompiledExpression( |
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349 | CompiledExpression::OBJECT |
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350 | ); |
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351 | case \phpDocumentor\Reflection\Types\Integer::class: |
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352 | return new CompiledExpression( |
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353 | CompiledExpression::INTEGER |
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354 | ); |
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355 | case \phpDocumentor\Reflection\Types\String_::class: |
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356 | return new CompiledExpression( |
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357 | CompiledExpression::STRING |
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358 | ); |
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359 | case \phpDocumentor\Reflection\Types\Float_::class: |
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360 | return new CompiledExpression( |
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361 | CompiledExpression::DOUBLE |
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362 | ); |
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363 | case \phpDocumentor\Reflection\Types\Null_::class: |
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364 | return new CompiledExpression( |
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365 | CompiledExpression::NULL |
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366 | ); |
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367 | case \phpDocumentor\Reflection\Types\Boolean::class: |
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368 | return new CompiledExpression( |
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369 | CompiledExpression::BOOLEAN |
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370 | ); |
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371 | } |
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372 | } |
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373 | } |
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374 | |||
375 | return new CompiledExpression(); |
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376 | } |
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377 | */ |
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378 | |||
379 | |||
380 | /** |
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381 | * @param Node\Expr\Variable $expr |
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382 | * @param mixed $value |
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383 | * @param int $type |
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384 | * @return CompiledExpression |
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385 | */ |
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386 | 2 | public function declareVariable(Node\Expr\Variable $expr, $value = null, $type = CompiledExpression::UNKNOWN) |
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387 | { |
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388 | 2 | $variable = $this->context->getSymbol($expr->name); |
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389 | 2 | if ($variable) { |
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390 | 1 | $variable->modify($type, $value); |
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391 | 1 | } else { |
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392 | 2 | $variable = new Variable($expr->name, $value, $type, $this->context->getCurrentBranch()); |
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393 | 2 | $this->context->addVariable($variable); |
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394 | } |
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395 | |||
396 | 2 | return new CompiledExpression($variable->getType(), $variable->getValue(), $variable); |
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397 | } |
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398 | |||
399 | /** |
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400 | * @param Node\Name\FullyQualified $expr |
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401 | * @return CompiledExpression |
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402 | */ |
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403 | 6 | public function getFullyQualifiedNodeName(Node\Name\FullyQualified $expr) |
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404 | { |
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405 | 6 | $compiler = $this->context->getApplication()->compiler; |
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406 | |||
407 | 6 | $classDefinition = $compiler->getClass($expr->toString()); |
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408 | 6 | if ($classDefinition) { |
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409 | return new CompiledExpression( |
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410 | CompiledExpression::OBJECT, |
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411 | $classDefinition |
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412 | ); |
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413 | } |
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414 | |||
415 | 6 | $this->context->debug('Unimplemented FullyQualified', $expr); |
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416 | 6 | return new CompiledExpression(); |
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417 | } |
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418 | |||
419 | /** |
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420 | * @param Node\Name $expr |
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421 | * @return CompiledExpression |
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422 | */ |
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423 | 31 | public function getNodeName(Node\Name $expr) |
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459 | } |
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460 |
The class complexity is the sum of the complexity of all methods. A very high value is usually an indication that your class does not follow the single reponsibility principle and does more than one job.
Some resources for further reading:
You can also find more detailed suggestions for refactoring in the “Code” section of your repository.