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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;
/**
* Lexes an expression.
*
* @author Fabien Potencier <fabien@symfony.com>
*/
class Lexer
{
/**
* Tokenizes an expression.
*
* @param string $expression The expression to tokenize
*
* @return TokenStream A token stream instance
*
* @throws SyntaxError
*/
public function tokenize($expression)
{
$expression = str_replace(["\r", "\n", "\t", "\v", "\f"], ' ', $expression);
$cursor = 0;
$tokens = [];
$brackets = [];
$end = \strlen($expression);
while ($cursor < $end) {
if (' ' == $expression[$cursor]) {
++$cursor;
continue;
}
if (preg_match('/[0-9]+(?:\.[0-9]+)?/A', $expression, $match, 0, $cursor)) {
// numbers
$number = (float) $match[0]; // floats
if (preg_match('/^[0-9]+$/', $match[0]) && $number <= PHP_INT_MAX) {
$number = (int) $match[0]; // integers lower than the maximum
}
$tokens[] = new Token(Token::NUMBER_TYPE, $number, $cursor + 1);
$cursor += \strlen($match[0]);
} elseif (false !== strpos('([{', $expression[$cursor])) {
// opening bracket
$brackets[] = [$expression[$cursor], $cursor];
$tokens[] = new Token(Token::PUNCTUATION_TYPE, $expression[$cursor], $cursor + 1);
++$cursor;
} elseif (false !== strpos(')]}', $expression[$cursor])) {
// closing bracket
if (empty($brackets)) {
throw new SyntaxError(sprintf('Unexpected "%s"', $expression[$cursor]), $cursor, $expression);
}
list($expect, $cur) = array_pop($brackets);
if ($expression[$cursor] != strtr($expect, '([{', ')]}')) {
throw new SyntaxError(sprintf('Unclosed "%s"', $expect), $cur, $expression);
}
$tokens[] = new Token(Token::PUNCTUATION_TYPE, $expression[$cursor], $cursor + 1);
++$cursor;
} elseif (preg_match('/"([^"\\\\]*(?:\\\\.[^"\\\\]*)*)"|\'([^\'\\\\]*(?:\\\\.[^\'\\\\]*)*)\'/As', $expression, $match, 0, $cursor)) {
// strings
$tokens[] = new Token(Token::STRING_TYPE, stripcslashes(substr($match[0], 1, -1)), $cursor + 1);
$cursor += \strlen($match[0]);
} elseif (preg_match('/not in(?=[\s(])|\!\=\=|not(?=[\s(])|and(?=[\s(])|\=\=\=|\>\=|or(?=[\s(])|\<\=|\*\*|\.\.|in(?=[\s(])|&&|\|\||matches|\=\=|\!\=|\*|~|%|\/|\>|\||\!|\^|&|\+|\<|\-/A', $expression, $match, 0, $cursor)) {
// operators
$tokens[] = new Token(Token::OPERATOR_TYPE, $match[0], $cursor + 1);
$cursor += \strlen($match[0]);
} elseif (false !== strpos('.,?:', $expression[$cursor])) {
// punctuation
$tokens[] = new Token(Token::PUNCTUATION_TYPE, $expression[$cursor], $cursor + 1);
++$cursor;
} elseif (preg_match('/[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*/A', $expression, $match, 0, $cursor)) {
// names
$tokens[] = new Token(Token::NAME_TYPE, $match[0], $cursor + 1);
$cursor += \strlen($match[0]);
} else {
// unlexable
throw new SyntaxError(sprintf('Unexpected character "%s"', $expression[$cursor]), $cursor, $expression);
}
}
$tokens[] = new Token(Token::EOF_TYPE, null, $cursor + 1);
if (!empty($brackets)) {
list($expect, $cur) = array_pop($brackets);
throw new SyntaxError(sprintf('Unclosed "%s"', $expect), $cur, $expression);
}
return new TokenStream($tokens, $expression);
}
}
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