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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\Parser; |
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use Railt\Compiler\Exception\ParserException; |
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use Railt\Compiler\Exception\UnexpectedTokenException; |
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use Railt\Compiler\Iterator\Buffer; |
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use Railt\Compiler\Iterator\BufferInterface; |
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use Railt\Compiler\Lexer\Result\Unknown; |
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use Railt\Compiler\LexerInterface; |
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use Railt\Compiler\Parser\Ast\Leaf; |
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use Railt\Compiler\Parser\Ast\Node; |
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use Railt\Compiler\Parser\Ast\NodeInterface; |
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use Railt\Compiler\Parser\Ast\Rule as AstRule; |
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use Railt\Compiler\Parser\Rule\Alternation; |
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use Railt\Compiler\Parser\Rule\Concatenation; |
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use Railt\Compiler\Parser\Rule\Repetition; |
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use Railt\Compiler\Parser\Rule\Symbol; |
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use Railt\Compiler\Parser\Rule\Token; |
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use Railt\Compiler\Parser\Trace\Entry; |
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use Railt\Compiler\Parser\Trace\Escape; |
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use Railt\Compiler\Parser\Trace\Invocation; |
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use Railt\Compiler\Parser\Trace\Terminator; |
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use Railt\Compiler\ParserInterface; |
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use Railt\Compiler\TokenInterface; |
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use Railt\Io\Readable; |
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/** |
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* Class Parser |
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*/ |
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abstract class Runtime implements ParserInterface |
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{ |
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/** |
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* Trace of activated rules. |
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* |
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* @var array |
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*/ |
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protected $trace = []; |
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/** |
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* Stack of todo list. |
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* |
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* @var array |
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*/ |
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protected $todo; |
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/** |
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* Current depth while building the trace. |
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* |
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* @var int |
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*/ |
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protected $depth = -1; |
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/** |
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* @var LexerInterface |
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*/ |
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private $lexer; |
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/** |
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* @var array |
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*/ |
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private $rules; |
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/** |
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* Construct the parser. |
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* |
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* @param LexerInterface $lexer |
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* @param array $rules Rules. |
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*/ |
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public function __construct(LexerInterface $lexer, array $rules = []) |
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{ |
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$this->rules = $rules; |
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$this->lexer = $lexer; |
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} |
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/** |
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* Parse :-). |
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* |
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* @param Readable $input |
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* @return NodeInterface |
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* @throws ParserException |
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* @throws \RuntimeException |
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*/ |
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public function parse(Readable $input): NodeInterface |
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{ |
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$buffer = new Buffer($this->lex($input), 1024); |
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$buffer->rewind(); |
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$this->trace = []; |
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$this->todo = []; |
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$rule = $this->getRootRule(); |
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$closeRule = new Escape($rule, 0); |
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$openRule = new Entry($rule, 0, [$closeRule]); |
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$this->todo = [$closeRule, $openRule]; |
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do { |
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$out = $this->unfold($buffer); |
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if ($out !== null && $buffer->current()->name() === TokenInterface::END_OF_INPUT) { |
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break; |
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} |
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if ($this->backtrack($buffer) === false) { |
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/** @var TokenInterface $token */ |
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$token = $buffer->top(); |
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$error = \sprintf('Unregistered token %s', $token); |
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throw UnexpectedTokenException::fromFile($error, $input, $token->offset()); |
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} |
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} while (true); |
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$ast = $this->buildTree(); |
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if (! ($ast instanceof NodeInterface)) { |
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throw new ParserException('Parsing error: cannot build AST, the trace is corrupted.', 1); |
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} |
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return $ast; |
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} |
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/** |
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* @param Readable $input |
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* @return \Traversable |
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*/ |
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private function lex(Readable $input): \Traversable |
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{ |
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foreach ($this->getLexer()->lex($input) as $token) { |
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if ($token instanceof Unknown) { |
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$error = \sprintf('Unexpected lexical token %s', $token); |
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throw UnexpectedTokenException::fromFile($error, $input, $token->offset()); |
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} |
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yield $token; |
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} |
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} |
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/** |
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* @return LexerInterface |
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*/ |
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public function getLexer(): LexerInterface |
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{ |
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return $this->lexer; |
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} |
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/** |
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* Get root rule. |
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* |
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* @return string |
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*/ |
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public function getRootRule(): string |
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{ |
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foreach ($this->rules as $rule => $_) { |
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if (\is_string($rule)) { |
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return $rule; |
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} |
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} |
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throw new \RuntimeException('Invalid grammar root rule (Can not find)'); |
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} |
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/** |
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* Unfold trace |
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* @param BufferInterface $buffer |
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* @return mixed |
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*/ |
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protected function unfold(BufferInterface $buffer) |
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{ |
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while (0 < \count($this->todo)) { |
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$rule = \array_pop($this->todo); |
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if ($rule instanceof Escape) { |
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$rule->setDepth($this->depth); |
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$this->trace($rule, $buffer); |
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if ($rule->isTransitional() === false) { |
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--$this->depth; |
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} |
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} else { |
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$out = $this->parseCurrentRule($buffer, $this->getRule($rule->getRule()), $rule->getData()); |
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if ($out === false && $this->backtrack($buffer) === false) { |
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return; |
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} |
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} |
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} |
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return true; |
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} |
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/** |
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* @param Invocation $invocation |
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* @param Buffer $buffer |
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*/ |
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private function trace(Invocation $invocation, Buffer $buffer): void |
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{ |
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$this->trace[] = $invocation; |
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$invocation->at($buffer->current()->offset()); |
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} |
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/** |
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* Parse current rule |
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* @param BufferInterface $buffer |
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* @param Symbol $rule Current rule. |
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* @param int $next Next rule index. |
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* @return bool |
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*/ |
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protected function parseCurrentRule(BufferInterface $buffer, Symbol $rule, $next): bool |
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{ |
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if ($rule instanceof Token) { |
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$name = $buffer->current()->name(); |
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if ($rule->getName() !== $name) { |
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return false; |
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} |
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$value = $buffer->current()->value(); |
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$current = $buffer->current(); |
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$offset = $current->offset(); |
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\array_pop($this->todo); |
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$this->trace[] = new Terminator($rule->getName(), $value, $offset, $rule->isKept()); |
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$buffer->next(); |
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return true; |
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} |
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if ($rule instanceof Concatenation) { |
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$this->trace(new Entry($rule->getId(), 0, null, $this->depth), $buffer); |
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$children = $rule->then(); |
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for ($i = \count($children) - 1; $i >= 0; --$i) { |
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$nextRule = $children[$i]; |
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$this->todo[] = new Escape($nextRule, 0); |
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$this->todo[] = new Entry($nextRule, 0); |
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} |
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return true; |
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} |
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if ($rule instanceof Alternation) { |
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$children = $rule->then(); |
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if ($next >= \count($children)) { |
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return false; |
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} |
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$this->trace(new Entry($rule->getId(), $next, $this->todo, $this->depth), $buffer); |
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/** @var string|int $nextRule */ |
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$nextRule = $children[$next]; |
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$this->todo[] = new Escape($nextRule, 0); |
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$this->todo[] = new Entry($nextRule, 0); |
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return true; |
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} |
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if ($rule instanceof Repetition) { |
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$nextRule = $rule->then()[0]; |
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if ($next === 0) { |
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$name = $rule->getId(); |
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$min = $rule->from(); |
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$this->trace(new Entry($name, $min, null, $this->depth), $buffer); |
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\array_pop($this->todo); |
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$this->todo[] = new Escape($name, $min, $this->todo); |
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for ($i = 0; $i < $min; ++$i) { |
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$this->todo[] = new Escape($nextRule, 0); |
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$this->todo[] = new Entry($nextRule, 0); |
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} |
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return true; |
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} |
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$max = $rule->to(); |
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if ($max !== Repetition::INF_MAX_VALUE && $next > $max) { |
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return false; |
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} |
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$this->todo[] = new Escape($rule->getId(), $next, $this->todo); |
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$this->todo[] = new Escape($nextRule, 0); |
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$this->todo[] = new Entry($nextRule, 0); |
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return true; |
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} |
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return false; |
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} |
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/** |
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* Get rule by name. |
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* |
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* @param $name |
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* @return Symbol|null |
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*/ |
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public function getRule($name): ?Symbol |
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{ |
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return $this->rules[$name] ?? null; |
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} |
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/** |
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* Backtrack the trace. |
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* |
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* @param BufferInterface $buffer |
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* @return bool |
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*/ |
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protected function backtrack(BufferInterface $buffer): bool |
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{ |
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$found = false; |
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do { |
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$last = \array_pop($this->trace); |
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if ($last instanceof Entry) { |
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$found = $this->getRule($last->getRule()) instanceof Alternation; |
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} elseif ($last instanceof Escape) { |
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$found = $this->getRule($last->getRule()) instanceof Repetition; |
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} elseif ($last instanceof Terminator) { |
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$buffer->previous(); |
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if ($buffer->valid() === false) { |
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return false; |
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} |
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} |
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} while (0 < \count($this->trace) && $found === false); |
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if ($found === false) { |
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return false; |
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} |
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$this->depth = $last->getDepth(); |
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$this->todo = $last->getTodo(); |
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$this->todo[] = new Entry($last->getRule(), $last->getData() + 1); |
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return true; |
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} |
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/** |
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* Build AST from trace. |
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* Walk through the trace iteratively and recursively. |
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* |
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* @param int $i Current trace index. |
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* @param array &$children Collected children. |
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* @return Node|int |
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*/ |
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protected function buildTree($i = 0, array &$children = []) |
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{ |
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$max = \count($this->trace); |
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while ($i < $max) { |
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/** @var Invocation|Terminator $trace */ |
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$trace = $this->trace[$i]; |
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if ($trace instanceof Entry) { |
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$ruleName = $trace->getRule(); |
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$rule = $this->rules[$ruleName]; |
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$isRule = $trace->isTransitional() === false; |
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$nextTrace = $this->trace[$i + 1]; |
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$id = $rule->getName(); |
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$offset = $trace->getOffset(); |
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// Optimization: Skip empty trace sequence. |
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if ($nextTrace instanceof Escape && $ruleName === $nextTrace->getRule()) { |
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$i += 2; |
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continue; |
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} |
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54 |
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if ($isRule === true) { |
383
|
54 |
|
$children[] = $ruleName; |
384
|
|
|
} |
385
|
|
|
|
386
|
54 |
|
if ($id !== null) { |
387
|
54 |
|
$children[] = [ |
388
|
54 |
|
'id' => $id, |
389
|
|
|
]; |
390
|
|
|
} |
391
|
|
|
|
392
|
54 |
|
$i = $this->buildTree($i + 1, $children); |
393
|
|
|
|
394
|
54 |
|
if ($isRule === false) { |
395
|
52 |
|
continue; |
396
|
|
|
} |
397
|
|
|
|
398
|
54 |
|
$handle = []; |
399
|
54 |
|
$cId = null; |
400
|
|
|
|
401
|
|
|
do { |
402
|
54 |
|
$pop = \array_pop($children); |
403
|
|
|
|
404
|
54 |
|
if (\is_object($pop) === true) { |
405
|
52 |
|
$handle[] = $pop; |
406
|
54 |
|
} elseif (\is_array($pop) === true && $cId === null) { |
407
|
54 |
|
$cId = $pop['id']; |
408
|
54 |
|
} elseif ($ruleName === $pop) { |
409
|
54 |
|
break; |
410
|
|
|
} |
411
|
54 |
|
} while ($pop !== null); |
412
|
|
|
|
413
|
54 |
|
if ($cId === null) { |
414
|
20 |
|
for ($j = \count($handle) - 1; $j >= 0; --$j) { |
415
|
20 |
|
$children[] = $handle[$j]; |
416
|
|
|
} |
417
|
|
|
|
418
|
20 |
|
continue; |
419
|
|
|
} |
420
|
|
|
|
421
|
54 |
|
$rule = new AstRule((string)($id ?: $cId), \array_reverse($handle), $offset); |
422
|
54 |
|
$children[] = $rule; |
423
|
54 |
|
} elseif ($trace instanceof Escape) { |
424
|
54 |
|
return $i + 1; |
425
|
|
|
} else { |
426
|
54 |
|
if ($trace->isKept() === false) { |
|
|
|
|
427
|
26 |
|
++$i; |
428
|
|
|
|
429
|
26 |
|
continue; |
430
|
|
|
} |
431
|
|
|
|
432
|
52 |
|
$children[] = new Leaf($trace->getName(), $trace->getValue(), $trace->getOffset()); |
|
|
|
|
433
|
52 |
|
++$i; |
434
|
|
|
} |
435
|
|
|
} |
436
|
|
|
|
437
|
54 |
|
return $children[0]; |
438
|
|
|
} |
439
|
|
|
|
440
|
|
|
/** |
441
|
|
|
* @return array |
442
|
|
|
*/ |
443
|
|
|
public function getRules(): array |
444
|
|
|
{ |
445
|
|
|
return $this->rules; |
446
|
|
|
} |
447
|
|
|
} |
448
|
|
|
|
This check looks for parameters that are defined as one type in their type hint or doc comment but seem to be used as a narrower type, i.e an implementation of an interface or a subclass.
Consider changing the type of the parameter or doing an instanceof check before assuming your parameter is of the expected type.