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