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