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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| 21 | class Expression |
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| 22 | { |
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| 23 | /** |
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| 24 | * @var Context |
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| 25 | */ |
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| 26 | protected $context; |
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| 27 | |||
| 28 | /** |
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| 29 | * @var EventManager |
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| 30 | */ |
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| 31 | protected $eventManager; |
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| 32 | |||
| 33 | /** |
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| 34 | * @param Context $context |
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| 35 | */ |
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| 36 | 851 | public function __construct(Context $context, EventManager $eventManager) |
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| 41 | |||
| 42 | /** |
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| 43 | * @param $expr |
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| 44 | * @return ExpressionCompilerInterface|AbstractExpressionCompiler |
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| 45 | */ |
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| 46 | 841 | protected function factory($expr) |
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| 47 | { |
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| 48 | 841 | switch (get_class($expr)) { |
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| 49 | /** |
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| 50 | * Call(s) |
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| 51 | */ |
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| 52 | 841 | case Node\Expr\MethodCall::class: |
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| 53 | return new Expression\MethodCall(); |
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| 54 | 841 | case Node\Expr\FuncCall::class: |
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| 55 | 10 | return new Expression\FunctionCall(); |
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| 56 | 837 | case Node\Expr\StaticCall::class: |
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| 57 | 1 | return new Expression\StaticCall(); |
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| 58 | /** |
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| 59 | * Operators |
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| 60 | */ |
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| 61 | 836 | case Node\Expr\New_::class: |
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| 62 | 2 | return new Expression\Operators\NewOp(); |
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| 63 | 836 | case Node\Expr\Instanceof_::class: |
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| 64 | return new Expression\Operators\InstanceOfOp(); |
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| 65 | /** |
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| 66 | * AssignOp |
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| 67 | */ |
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| 68 | 836 | case Node\Expr\AssignOp\Pow::class: |
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| 69 | 21 | return new Expression\AssignOp\Pow(); |
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| 70 | 815 | case Node\Expr\AssignOp\Plus::class: |
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| 71 | 17 | return new Expression\AssignOp\Plus(); |
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| 72 | 798 | case Node\Expr\AssignOp\Minus::class: |
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| 73 | 20 | return new Expression\AssignOp\Minus(); |
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| 74 | 778 | case Node\Expr\AssignOp\Mul::class: |
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| 75 | 20 | return new Expression\AssignOp\Mul(); |
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| 76 | 758 | case Node\Expr\AssignOp\Div::class: |
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| 77 | 18 | return new Expression\AssignOp\Div(); |
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| 78 | 740 | case Node\Expr\AssignOp\Mod::class: |
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| 79 | 11 | return new Expression\AssignOp\Mod(); |
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| 80 | 729 | case Node\Expr\AssignOp\BitwiseOr::class: |
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| 81 | 12 | return new Expression\AssignOp\BitwiseOr(); |
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| 82 | 717 | case Node\Expr\AssignOp\BitwiseAnd::class: |
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| 83 | 12 | return new Expression\AssignOp\BitwiseAnd(); |
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| 84 | 705 | case Node\Expr\AssignOp\BitwiseXor::class: |
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| 85 | 12 | return new Expression\AssignOp\BitwiseXor(); |
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| 86 | 693 | case Node\Expr\AssignOp\Concat::class: |
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| 87 | 14 | return new Expression\AssignOp\Concat(); |
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| 88 | 679 | case Node\Expr\AssignOp\ShiftLeft::class: |
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| 89 | 12 | return new Expression\AssignOp\ShiftLeft(); |
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| 90 | 667 | case Node\Expr\AssignOp\ShiftRight::class: |
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| 91 | 12 | return new Expression\AssignOp\ShiftRight(); |
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| 92 | |||
| 93 | /** |
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| 94 | * BinaryOp |
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| 95 | */ |
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| 96 | 655 | case Node\Expr\BinaryOp\Identical::class: |
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| 97 | 28 | return new Expression\BinaryOp\Identical(); |
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| 98 | 627 | case Node\Expr\BinaryOp\Concat::class: |
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| 99 | 15 | return new Expression\Operators\Concat(); |
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| 100 | 613 | case Node\Expr\BinaryOp\NotIdentical::class: |
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| 101 | 14 | return new Expression\BinaryOp\NotIdentical(); |
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| 102 | 599 | case Node\Expr\BinaryOp\Equal::class: |
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| 103 | 43 | return new Expression\BinaryOp\Equal(); |
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| 104 | 570 | case Node\Expr\BinaryOp\NotEqual::class: |
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| 105 | 17 | return new Expression\BinaryOp\NotEqual(); |
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| 106 | 553 | case Node\Expr\BinaryOp\Spaceship::class: |
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| 107 | 11 | return new Expression\BinaryOp\SpaceShip(); |
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| 108 | 544 | case Node\Expr\BinaryOp\Coalesce::class: |
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| 109 | 3 | return new Expression\BinaryOp\Coalesce(); |
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| 110 | |||
| 111 | /** |
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| 112 | * @link http://php.net/manual/en/language.operators.increment.php |
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| 113 | */ |
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| 114 | 542 | case Node\Expr\PostInc::class: |
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| 115 | 8 | return new Expression\Operators\PostInc(); |
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| 116 | 534 | case Node\Expr\PostDec::class: |
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| 117 | 8 | return new Expression\Operators\PostDec(); |
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| 118 | 526 | case Node\Expr\PreInc::class: |
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| 119 | 8 | return new Expression\Operators\PreInc(); |
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| 120 | 518 | case Node\Expr\PreDec::class: |
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| 121 | 8 | return new Expression\Operators\PreDec(); |
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| 122 | /** |
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| 123 | * Arithmetical |
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| 124 | */ |
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| 125 | 510 | case Node\Expr\BinaryOp\Div::class: |
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| 126 | 37 | return new Expression\Operators\Arithmetical\Div(); |
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| 127 | 473 | case Node\Expr\BinaryOp\Plus::class: |
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| 128 | 45 | return new Expression\Operators\Arithmetical\Plus(); |
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| 129 | 432 | case Node\Expr\BinaryOp\Minus::class: |
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| 130 | 24 | return new Expression\Operators\Arithmetical\Minus(); |
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| 131 | 408 | case Node\Expr\BinaryOp\Mul::class: |
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| 132 | 35 | return new Expression\Operators\Arithmetical\Mul(); |
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| 133 | 373 | case Node\Expr\BinaryOp\Mod::class: |
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| 134 | 35 | return new Expression\Operators\Arithmetical\Mod(); |
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| 135 | 338 | case Node\Expr\BinaryOp\Pow::class: |
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| 136 | 21 | return new Expression\Operators\Arithmetical\Pow(); |
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| 137 | |||
| 138 | /** |
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| 139 | * Bitwise |
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| 140 | * @link http://php.net/manual/ru/language.operators.bitwise.php |
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| 141 | */ |
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| 142 | 317 | case Node\Expr\BinaryOp\BitwiseOr::class: |
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| 143 | 12 | return new Expression\Operators\Bitwise\BitwiseOr(); |
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| 144 | 305 | case Node\Expr\BinaryOp\BitwiseXor::class: |
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| 145 | 12 | return new Expression\Operators\Bitwise\BitwiseXor(); |
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| 146 | 293 | case Node\Expr\BinaryOp\BitwiseAnd::class: |
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| 147 | 12 | return new Expression\Operators\Bitwise\BitwiseAnd(); |
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| 148 | 281 | case Node\Expr\BinaryOp\ShiftRight::class: |
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| 149 | 12 | return new Expression\Operators\Bitwise\ShiftRight(); |
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| 150 | 269 | case Node\Expr\BinaryOp\ShiftLeft::class: |
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| 151 | 12 | return new Expression\Operators\Bitwise\ShiftLeft(); |
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| 152 | 257 | case Node\Expr\BitwiseNot::class: |
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| 153 | 5 | return new Expression\Operators\Bitwise\BitwiseNot(); |
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| 154 | /** |
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| 155 | * Logical |
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| 156 | */ |
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| 157 | 252 | case Node\Expr\BinaryOp\BooleanOr::class: |
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| 158 | 17 | return new Expression\Operators\Logical\BooleanOr(); |
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| 159 | 237 | case Node\Expr\BinaryOp\BooleanAnd::class: |
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| 160 | 15 | return new Expression\Operators\Logical\BooleanAnd(); |
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| 161 | 224 | case Node\Expr\BooleanNot::class: |
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| 162 | 9 | return new Expression\Operators\Logical\BooleanNot(); |
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| 163 | 216 | case Node\Expr\BinaryOp\LogicalAnd::class: |
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| 164 | 15 | return new Expression\Operators\Logical\LogicalAnd(); |
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| 165 | 203 | case Node\Expr\BinaryOp\LogicalOr::class: |
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| 166 | 17 | return new Expression\Operators\Logical\LogicalOr(); |
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| 167 | 188 | case Node\Expr\BinaryOp\LogicalXor::class: |
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| 168 | 17 | return new Expression\Operators\Logical\LogicalXor(); |
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| 169 | |||
| 170 | /** |
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| 171 | * Comparison |
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| 172 | */ |
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| 173 | 173 | case Node\Expr\BinaryOp\Greater::class: |
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| 174 | 13 | return new Expression\Operators\Comparison\Greater(); |
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| 175 | 161 | case Node\Expr\BinaryOp\GreaterOrEqual::class: |
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| 176 | 12 | return new Expression\Operators\Comparison\GreaterOrEqual(); |
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| 177 | 149 | case Node\Expr\BinaryOp\Smaller::class: |
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| 178 | 12 | return new Expression\Operators\Comparison\Smaller(); |
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| 179 | 137 | case Node\Expr\BinaryOp\SmallerOrEqual::class: |
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| 180 | 12 | return new Expression\Operators\Comparison\SmallerOrEqual(); |
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| 181 | |||
| 182 | /** |
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| 183 | * Casts |
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| 184 | */ |
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| 185 | 125 | case Node\Expr\Cast\Array_::class: |
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| 186 | 3 | return new Expression\Casts\ArrayCast(); |
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| 187 | 124 | case Node\Expr\Cast\Bool_::class: |
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| 188 | 8 | return new Expression\Casts\BoolCast(); |
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| 189 | 118 | case Node\Expr\Cast\Int_::class: |
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| 190 | 8 | return new Expression\Casts\IntCast(); |
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| 191 | 112 | case Node\Expr\Cast\Double::class: |
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| 192 | 8 | return new Expression\Casts\DoubleCast(); |
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| 193 | 106 | case Node\Expr\Cast\Object_::class: |
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| 194 | 2 | return new Expression\Casts\ObjectCast(); |
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| 195 | 105 | case Node\Expr\Cast\String_::class: |
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| 196 | 7 | return new Expression\Casts\StringCast(); |
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| 197 | 99 | case Node\Expr\Cast\Unset_::class: |
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| 198 | 2 | return new Expression\Casts\UnsetCast(); |
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| 199 | |||
| 200 | |||
| 201 | /** |
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| 202 | * Other |
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| 203 | */ |
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| 204 | 98 | case Node\Expr\Array_::class: |
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| 205 | 37 | return new Expression\ArrayOp(); |
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| 206 | 69 | case Node\Expr\Assign::class: |
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| 207 | 30 | return new Expression\Assign(); |
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| 208 | 51 | case Node\Expr\AssignRef::class: |
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| 209 | 1 | return new Expression\AssignRef(); |
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| 210 | 51 | case Node\Expr\Closure::class: |
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| 211 | return new Expression\Closure(); |
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| 212 | 51 | case Node\Expr\ConstFetch::class: |
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| 213 | 7 | return new Expression\ConstFetch(); |
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| 214 | 48 | case Node\Expr\ClassConstFetch::class: |
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| 215 | return new Expression\ClassConstFetch(); |
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| 216 | 48 | case Node\Expr\PropertyFetch::class: |
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| 217 | return new Expression\PropertyFetch(); |
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| 218 | 48 | case Node\Expr\ArrayDimFetch::class: |
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| 219 | return new Expression\ArrayDimFetch(); |
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| 220 | 48 | case Node\Expr\UnaryMinus::class: |
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| 221 | 9 | return new Expression\Operators\UnaryMinus(); |
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| 222 | 39 | case Node\Expr\UnaryPlus::class: |
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| 223 | 9 | return new Expression\Operators\UnaryPlus(); |
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| 224 | 30 | case Node\Expr\Exit_::class: |
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| 225 | 1 | return new Expression\ExitOp(); |
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| 226 | 29 | case Node\Expr\Isset_::class: |
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| 227 | 3 | return new Expression\IssetOp(); |
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| 228 | 26 | case Node\Expr\Print_::class: |
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| 229 | 2 | return new Expression\PrintOp(); |
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| 230 | 25 | case Node\Expr\Empty_::class: |
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| 231 | 5 | return new Expression\EmptyOp(); |
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| 232 | 20 | case Node\Expr\Eval_::class: |
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| 233 | 2 | return new Expression\EvalOp(); |
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| 234 | 18 | case Node\Expr\ErrorSuppress::class: |
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| 235 | 2 | return new Expression\ErrorSuppress(); |
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| 236 | 16 | case Node\Expr\Clone_::class: |
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| 237 | 1 | return new Expression\CloneOp(); |
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| 238 | 15 | case Node\Expr\Ternary::class: |
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| 239 | 2 | return new Expression\Ternary(); |
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| 240 | 13 | case Node\Expr\Variable::class: |
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| 241 | 12 | return new Expression\Variable(); |
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| 242 | 1 | } |
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| 243 | |||
| 244 | 1 | return false; |
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| 245 | } |
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| 246 | |||
| 247 | /** |
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| 248 | * @param object|string $expr |
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| 249 | * @throws InvalidArgumentException when $expr is not string/object/null |
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| 250 | * @throws RuntimeException when compiler class does not return a CompiledExpression |
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| 251 | * @return CompiledExpression |
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| 252 | */ |
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| 253 | 851 | public function compile($expr) |
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| 254 | { |
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| 255 | 851 | if (is_string($expr)) { |
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| 256 | 17 | return new CompiledExpression(CompiledExpression::STRING, $expr); |
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| 257 | } |
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| 258 | |||
| 259 | 851 | if (is_null($expr)) { |
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| 260 | 8 | return new CompiledExpression(CompiledExpression::NULL); |
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| 261 | } |
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| 262 | |||
| 263 | 851 | if (!is_object($expr)) { |
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| 264 | throw new InvalidArgumentException('$expr must be string/object/null'); |
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| 265 | } |
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| 266 | |||
| 267 | 851 | $this->eventManager->fire( |
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| 268 | 851 | ExpressionBeforeCompile::EVENT_NAME, |
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| 269 | 851 | new ExpressionBeforeCompile( |
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| 270 | 851 | $expr, |
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| 271 | 851 | $this->context |
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| 272 | 851 | ) |
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| 273 | 851 | ); |
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| 274 | |||
| 275 | 851 | $className = get_class($expr); |
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| 276 | switch ($className) { |
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| 277 | 851 | case Node\Arg::class: |
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| 278 | /** |
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| 279 | * @todo Better compile |
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| 280 | */ |
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| 281 | 2 | return $this->compile($expr->value); |
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| 282 | 851 | case Node\Stmt\Property::class: |
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| 283 | return $this->passProperty($expr); |
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| 284 | |||
| 285 | /** |
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| 286 | * Expressions |
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| 287 | */ |
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| 288 | 851 | case Node\Name::class: |
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| 289 | 27 | return $this->getNodeName($expr); |
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| 290 | 851 | case Node\Name\FullyQualified::class: |
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| 291 | return $this->getFullyQualifiedNodeName($expr); |
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| 292 | |||
| 293 | /** |
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| 294 | * Simple Scalar(s) |
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| 295 | */ |
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| 296 | 851 | case \PHPSA\Node\Scalar\Nil::class: |
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| 297 | 25 | return new CompiledExpression(CompiledExpression::NULL); |
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| 298 | 850 | case Node\Scalar\LNumber::class: |
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| 299 | 514 | return new CompiledExpression(CompiledExpression::INTEGER, $expr->value); |
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| 300 | 845 | case Node\Scalar\DNumber::class: |
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| 301 | 212 | return new CompiledExpression(CompiledExpression::DOUBLE, $expr->value); |
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| 302 | 844 | case Node\Scalar\String_::class: |
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| 303 | 50 | return new CompiledExpression(CompiledExpression::STRING, $expr->value); |
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| 304 | 843 | case \PHPSA\Node\Scalar\Boolean::class: |
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| 305 | 241 | return new CompiledExpression(CompiledExpression::BOOLEAN, $expr->value); |
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| 306 | 841 | case \PHPSA\Node\Scalar\Fake::class: |
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| 307 | 79 | return new CompiledExpression($expr->type, $expr->value); |
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| 308 | } |
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| 309 | |||
| 310 | 841 | $expressionCompiler = $this->factory($expr); |
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| 311 | 841 | if (!$expressionCompiler) { |
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| 312 | 1 | $this->context->debug("Expression compiler is not implemented for {$className}"); |
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| 313 | 1 | return new CompiledExpression(CompiledExpression::UNIMPLEMENTED); |
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| 314 | } |
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| 315 | |||
| 316 | 841 | $result = $expressionCompiler->pass($expr, $this->context); |
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| 317 | 841 | if (!$result instanceof CompiledExpression) { |
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| 318 | throw new RuntimeException('Please return CompiledExpression from ' . get_class($expressionCompiler)); |
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| 319 | } |
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| 320 | |||
| 321 | 841 | return $result; |
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| 322 | } |
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| 323 | |||
| 324 | /** |
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| 325 | * @todo Implement - needs to be a new analyzer for var docblock |
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| 326 | * |
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| 327 | * @param Node\Stmt\Property $st |
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| 328 | * @return CompiledExpression |
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| 329 | */ |
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| 330 | public function passProperty(Node\Stmt\Property $st) |
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| 384 | |||
| 385 | /** |
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| 386 | * @param Node\Expr\Variable $expr |
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| 387 | * @param mixed $value |
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| 388 | * @param int $type |
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| 389 | * @return CompiledExpression |
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| 390 | */ |
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| 391 | 1 | public function declareVariable(Node\Expr\Variable $expr, $value = null, $type = CompiledExpression::UNKNOWN) |
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| 401 | |||
| 402 | /** |
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| 403 | * @param Node\Name\FullyQualified $expr |
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| 404 | * @return CompiledExpression |
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| 405 | */ |
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| 406 | public function getFullyQualifiedNodeName(Node\Name\FullyQualified $expr) |
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| 412 | |||
| 413 | /** |
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| 414 | * @param Node\Name $expr |
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| 415 | * @return CompiledExpression |
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| 416 | */ |
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| 417 | 27 | public function getNodeName(Node\Name $expr) |
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| 453 | } |
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| 454 |
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.