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<?php |
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/** |
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* This file is part of Railt package. |
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* |
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* For the full copyright and license information, please view the LICENSE |
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* file that was distributed with this source code. |
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*/ |
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declare(strict_types=1); |
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namespace Railt\Compiler\Grammar; |
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/** |
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* Class LookaheadIterator |
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*/ |
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class LookaheadIterator extends \IteratorIterator |
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{ |
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/** |
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* Current key. |
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* |
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* @var mixed |
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*/ |
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protected $key = 0; |
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/** |
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* Current value. |
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* |
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* @var mixed |
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*/ |
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protected $current; |
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/** |
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* Whether the current element is valid or not. |
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* |
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* @var bool |
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*/ |
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protected $valid = false; |
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/** |
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* LookaheadIterator constructor. |
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* @param iterable $iterator |
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*/ |
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public function __construct(iterable $iterator) |
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{ |
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parent::__construct($this->toIterator($iterator)); |
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$this->rewind(); |
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} |
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/** |
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* @param iterable $iterable |
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* @return \Traversable |
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*/ |
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private function toIterator(iterable $iterable): \Traversable |
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{ |
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return $iterable instanceof \Traversable ? $iterable : new \ArrayIterator($iterable); |
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} |
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/** |
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* Return the current element. |
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* |
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* @return mixed |
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*/ |
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public function current() |
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{ |
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return $this->current; |
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} |
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/** |
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* Return the key of the current element. |
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* |
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* @return mixed |
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*/ |
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public function key() |
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{ |
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return $this->key; |
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} |
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/** |
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* Rewind the iterator to the first element. |
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* |
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* @return void |
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*/ |
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public function rewind(): void |
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{ |
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$this->getInnerIterator()->rewind(); |
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$this->next(); |
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} |
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/** |
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* Move forward to next element. |
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* |
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* @return void |
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*/ |
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public function next(): void |
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{ |
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$innerIterator = $this->getInnerIterator(); |
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$this->valid = $innerIterator->valid(); |
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if ($this->valid === false) { |
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return; |
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} |
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$this->key = $innerIterator->key(); |
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$this->current = $innerIterator->current(); |
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$innerIterator->next(); |
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} |
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/** |
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* Check if current position is valid. |
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* |
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* @return bool |
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*/ |
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public function valid(): bool |
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{ |
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return $this->valid; |
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} |
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/** |
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* Check whether there is a next element. |
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* |
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* @return bool |
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*/ |
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public function hasNext(): bool |
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{ |
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return $this->getInnerIterator()->valid(); |
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} |
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/** |
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* Get next value. |
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* |
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* @return mixed |
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*/ |
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public function getNext() |
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{ |
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return $this->getInnerIterator()->current(); |
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} |
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/** |
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* Get next key. |
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* |
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* @return mixed |
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*/ |
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public function getNextKey() |
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{ |
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return $this->getInnerIterator()->key(); |
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} |
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} |
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railt /
compiler
