84 lines
2.0 KiB
PHP
84 lines
2.0 KiB
PHP
<?php
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/*
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* This file is part of the Symfony package.
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*
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* (c) Fabien Potencier <fabien@symfony.com>
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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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namespace Symfony\Component\ExpressionLanguage;
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/**
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* Represents a token stream.
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*
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* @author Fabien Potencier <fabien@symfony.com>
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*/
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class TokenStream
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{
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public $current;
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private array $tokens;
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private int $position = 0;
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private string $expression;
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public function __construct(array $tokens, string $expression = '')
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{
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$this->tokens = $tokens;
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$this->current = $tokens[0];
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$this->expression = $expression;
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}
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/**
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* Returns a string representation of the token stream.
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*/
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public function __toString(): string
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{
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return implode("\n", $this->tokens);
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}
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/**
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* Sets the pointer to the next token and returns the old one.
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*/
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public function next()
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{
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++$this->position;
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if (!isset($this->tokens[$this->position])) {
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throw new SyntaxError('Unexpected end of expression.', $this->current->cursor, $this->expression);
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}
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$this->current = $this->tokens[$this->position];
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}
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/**
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* @param string|null $message The syntax error message
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*/
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public function expect(string $type, string $value = null, string $message = null)
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{
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$token = $this->current;
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if (!$token->test($type, $value)) {
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throw new SyntaxError(sprintf('%sUnexpected token "%s" of value "%s" ("%s" expected%s).', $message ? $message.'. ' : '', $token->type, $token->value, $type, $value ? sprintf(' with value "%s"', $value) : ''), $token->cursor, $this->expression);
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}
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$this->next();
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}
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/**
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* Checks if end of stream was reached.
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*/
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public function isEOF(): bool
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{
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return Token::EOF_TYPE === $this->current->type;
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}
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/**
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* @internal
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*/
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public function getExpression(): string
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{
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return $this->expression;
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}
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}
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