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<?php |
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declare(strict_types=1); |
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namespace Remorhaz\UniLex\Parser; |
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use Remorhaz\UniLex\Exception; |
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use Remorhaz\UniLex\Stack\StackableSymbolInterface; |
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class Production implements StackableSymbolInterface |
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{ |
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private $header; |
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private $index; |
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private $symbolList; |
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public function __construct(Symbol $header, int $index, Symbol ...$symbolList) |
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{ |
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$this->header = $header; |
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$this->index = $index; |
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$this->symbolList = $symbolList; |
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} |
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public function __toString() |
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{ |
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return "{$this->header->getSymbolId()}:{$this->index}"; |
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} |
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/** |
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* @return array|AttributeListShortcut |
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*/ |
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public function getHeaderShortcut(): AttributeListShortcut |
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{ |
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return $this->header->getShortcut(); |
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} |
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/** |
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* @return array[]|SymbolListShortcut |
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*/ |
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public function getSymbolListShortcut(): SymbolListShortcut |
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{ |
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return new SymbolListShortcut($this); |
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} |
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public function getHeader(): Symbol |
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{ |
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return $this->header; |
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} |
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public function getIndex(): int |
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{ |
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return $this->index; |
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} |
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/** |
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* @return Symbol[] |
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*/ |
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public function getSymbolList(): array |
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{ |
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return $this->symbolList; |
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} |
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/** |
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* @param int $index |
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* @return Symbol |
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* @throws Exception |
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*/ |
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public function getSymbol(int $index): Symbol |
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{ |
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if (!$this->symbolExists($index)) { |
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throw new Exception("Symbol at index {$index} is undefined in production {$this}"); |
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} |
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return $this->symbolList[$index]; |
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} |
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public function isEpsilon(): bool |
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{ |
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return empty($this->getSymbolList()); |
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} |
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public function symbolExists(int $index): bool |
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{ |
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return isset($this->symbolList[$index]); |
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} |
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} |
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