383 lines
14 KiB
PHP
383 lines
14 KiB
PHP
<?php
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/*
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* This file is part of Twig.
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*
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* (c) 2009 Fabien Potencier
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* (c) 2009 Armin Ronacher
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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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/**
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* Parses expressions.
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*
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* This parser implements a "Precedence climbing" algorithm.
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*
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* @see http://www.engr.mun.ca/~theo/Misc/exp_parsing.htm
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* @see http://en.wikipedia.org/wiki/Operator-precedence_parser
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*
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* @package twig
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* @author Fabien Potencier <fabien@symfony.com>
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*/
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class Twig_ExpressionParser
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{
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const OPERATOR_LEFT = 1;
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const OPERATOR_RIGHT = 2;
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protected $parser;
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protected $unaryOperators;
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protected $binaryOperators;
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public function __construct(Twig_Parser $parser, array $unaryOperators, array $binaryOperators)
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{
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$this->parser = $parser;
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$this->unaryOperators = $unaryOperators;
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$this->binaryOperators = $binaryOperators;
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}
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public function parseExpression($precedence = 0)
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{
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$expr = $this->getPrimary();
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$token = $this->parser->getCurrentToken();
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while ($this->isBinary($token) && $this->binaryOperators[$token->getValue()]['precedence'] >= $precedence) {
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$op = $this->binaryOperators[$token->getValue()];
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$this->parser->getStream()->next();
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if (isset($op['callable'])) {
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$expr = call_user_func($op['callable'], $this->parser, $expr);
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} else {
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$expr1 = $this->parseExpression(self::OPERATOR_LEFT === $op['associativity'] ? $op['precedence'] + 1 : $op['precedence']);
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$class = $op['class'];
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$expr = new $class($expr, $expr1, $token->getLine());
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}
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$token = $this->parser->getCurrentToken();
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}
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if (0 === $precedence) {
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return $this->parseConditionalExpression($expr);
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}
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return $expr;
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}
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protected function getPrimary()
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{
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$token = $this->parser->getCurrentToken();
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if ($this->isUnary($token)) {
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$operator = $this->unaryOperators[$token->getValue()];
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$this->parser->getStream()->next();
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$expr = $this->parseExpression($operator['precedence']);
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$class = $operator['class'];
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return $this->parsePostfixExpression(new $class($expr, $token->getLine()));
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} elseif ($token->test(Twig_Token::PUNCTUATION_TYPE, '(')) {
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$this->parser->getStream()->next();
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$expr = $this->parseExpression();
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$this->parser->getStream()->expect(Twig_Token::PUNCTUATION_TYPE, ')', 'An opened parenthesis is not properly closed');
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return $this->parsePostfixExpression($expr);
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}
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return $this->parsePrimaryExpression();
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}
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protected function parseConditionalExpression($expr)
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{
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while ($this->parser->getStream()->test(Twig_Token::PUNCTUATION_TYPE, '?')) {
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$this->parser->getStream()->next();
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$expr2 = $this->parseExpression();
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$this->parser->getStream()->expect(Twig_Token::PUNCTUATION_TYPE, ':', 'The ternary operator must have a default value');
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$expr3 = $this->parseExpression();
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$expr = new Twig_Node_Expression_Conditional($expr, $expr2, $expr3, $this->parser->getCurrentToken()->getLine());
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}
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return $expr;
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}
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protected function isUnary(Twig_Token $token)
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{
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return $token->test(Twig_Token::OPERATOR_TYPE) && isset($this->unaryOperators[$token->getValue()]);
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}
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protected function isBinary(Twig_Token $token)
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{
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return $token->test(Twig_Token::OPERATOR_TYPE) && isset($this->binaryOperators[$token->getValue()]);
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}
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public function parsePrimaryExpression()
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{
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$token = $this->parser->getCurrentToken();
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switch ($token->getType()) {
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case Twig_Token::NAME_TYPE:
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$this->parser->getStream()->next();
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switch ($token->getValue()) {
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case 'true':
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case 'TRUE':
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$node = new Twig_Node_Expression_Constant(true, $token->getLine());
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break;
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case 'false':
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case 'FALSE':
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$node = new Twig_Node_Expression_Constant(false, $token->getLine());
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break;
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case 'none':
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case 'NONE':
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case 'null':
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case 'NULL':
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$node = new Twig_Node_Expression_Constant(null, $token->getLine());
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break;
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default:
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if ('(' === $this->parser->getCurrentToken()->getValue()) {
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$node = $this->getFunctionNode($token->getValue(), $token->getLine());
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} else {
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$node = new Twig_Node_Expression_Name($token->getValue(), $token->getLine());
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}
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}
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break;
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case Twig_Token::NUMBER_TYPE:
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case Twig_Token::STRING_TYPE:
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$this->parser->getStream()->next();
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$node = new Twig_Node_Expression_Constant($token->getValue(), $token->getLine());
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break;
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default:
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if ($token->test(Twig_Token::PUNCTUATION_TYPE, '[')) {
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$node = $this->parseArrayExpression();
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} elseif ($token->test(Twig_Token::PUNCTUATION_TYPE, '{')) {
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$node = $this->parseHashExpression();
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} else {
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throw new Twig_Error_Syntax(sprintf('Unexpected token "%s" of value "%s"', Twig_Token::typeToEnglish($token->getType(), $token->getLine()), $token->getValue()), $token->getLine());
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}
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}
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return $this->parsePostfixExpression($node);
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}
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public function parseArrayExpression()
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{
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$stream = $this->parser->getStream();
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$stream->expect(Twig_Token::PUNCTUATION_TYPE, '[', 'An array element was expected');
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$elements = array();
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while (!$stream->test(Twig_Token::PUNCTUATION_TYPE, ']')) {
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if (!empty($elements)) {
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$stream->expect(Twig_Token::PUNCTUATION_TYPE, ',', 'An array element must be followed by a comma');
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// trailing ,?
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if ($stream->test(Twig_Token::PUNCTUATION_TYPE, ']')) {
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break;
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}
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}
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$elements[] = $this->parseExpression();
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}
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$stream->expect(Twig_Token::PUNCTUATION_TYPE, ']', 'An opened array is not properly closed');
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return new Twig_Node_Expression_Array($elements, $stream->getCurrent()->getLine());
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}
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public function parseHashExpression()
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{
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$stream = $this->parser->getStream();
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$stream->expect(Twig_Token::PUNCTUATION_TYPE, '{', 'A hash element was expected');
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$elements = array();
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while (!$stream->test(Twig_Token::PUNCTUATION_TYPE, '}')) {
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if (!empty($elements)) {
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$stream->expect(Twig_Token::PUNCTUATION_TYPE, ',', 'A hash value must be followed by a comma');
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// trailing ,?
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if ($stream->test(Twig_Token::PUNCTUATION_TYPE, '}')) {
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break;
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}
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}
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if (!$stream->test(Twig_Token::STRING_TYPE) && !$stream->test(Twig_Token::NUMBER_TYPE)) {
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$current = $stream->getCurrent();
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throw new Twig_Error_Syntax(sprintf('A hash key must be a quoted string or a number (unexpected token "%s" of value "%s"', Twig_Token::typeToEnglish($current->getType(), $current->getLine()), $current->getValue()), $current->getLine());
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}
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$key = $stream->next()->getValue();
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$stream->expect(Twig_Token::PUNCTUATION_TYPE, ':', 'A hash key must be followed by a colon (:)');
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$elements[$key] = $this->parseExpression();
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}
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$stream->expect(Twig_Token::PUNCTUATION_TYPE, '}', 'An opened hash is not properly closed');
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return new Twig_Node_Expression_Array($elements, $stream->getCurrent()->getLine());
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}
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public function parsePostfixExpression($node)
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{
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while (true) {
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$token = $this->parser->getCurrentToken();
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if ($token->getType() == Twig_Token::PUNCTUATION_TYPE) {
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if ('.' == $token->getValue() || '[' == $token->getValue()) {
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$node = $this->parseSubscriptExpression($node);
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} elseif ('|' == $token->getValue()) {
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$node = $this->parseFilterExpression($node);
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} else {
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break;
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}
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} else {
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break;
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}
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}
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return $node;
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}
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public function getFunctionNode($name, $line)
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{
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$args = $this->parseArguments();
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switch ($name) {
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case 'parent':
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if (!count($this->parser->getBlockStack())) {
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throw new Twig_Error_Syntax('Calling "parent" outside a block is forbidden', $line);
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}
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if (!$this->parser->getParent()) {
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throw new Twig_Error_Syntax('Calling "parent" on a template that does not extend another one is forbidden', $line);
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}
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return new Twig_Node_Expression_Parent($this->parser->peekBlockStack(), $line);
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case 'block':
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return new Twig_Node_Expression_BlockReference($args->getNode(0), false, $line);
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case 'attribute':
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if (count($args) < 2) {
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throw new Twig_Error_Syntax('The "attribute" function takes at least two arguments (the variable and the attribute)', $line);
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}
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return new Twig_Node_Expression_GetAttr($args->getNode(0), $args->getNode(1), count($args) > 2 ? $args->getNode(2) : new Twig_Node_Expression_Array(array(), $line), Twig_TemplateInterface::ANY_CALL, $line);
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default:
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if (null !== $alias = $this->parser->getImportedFunction($name)) {
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return new Twig_Node_Expression_GetAttr($alias['node'], new Twig_Node_Expression_Constant($alias['name'], $line), $args, Twig_TemplateInterface::METHOD_CALL, $line);
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}
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return new Twig_Node_Expression_Function($name, $args, $line);
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}
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}
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public function parseSubscriptExpression($node)
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{
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$token = $this->parser->getStream()->next();
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$lineno = $token->getLine();
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$arguments = new Twig_Node();
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$type = Twig_TemplateInterface::ANY_CALL;
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if ($token->getValue() == '.') {
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$token = $this->parser->getStream()->next();
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if (
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$token->getType() == Twig_Token::NAME_TYPE
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||
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$token->getType() == Twig_Token::NUMBER_TYPE
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($token->getType() == Twig_Token::OPERATOR_TYPE && preg_match(Twig_Lexer::REGEX_NAME, $token->getValue()))
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) {
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$arg = new Twig_Node_Expression_Constant($token->getValue(), $lineno);
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if ($this->parser->getStream()->test(Twig_Token::PUNCTUATION_TYPE, '(')) {
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$type = Twig_TemplateInterface::METHOD_CALL;
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$arguments = $this->parseArguments();
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} else {
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$arguments = new Twig_Node();
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}
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} else {
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throw new Twig_Error_Syntax('Expected name or number', $lineno);
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}
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} else {
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$type = Twig_TemplateInterface::ARRAY_CALL;
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$arg = $this->parseExpression();
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$this->parser->getStream()->expect(Twig_Token::PUNCTUATION_TYPE, ']');
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}
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return new Twig_Node_Expression_GetAttr($node, $arg, $arguments, $type, $lineno);
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}
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public function parseFilterExpression($node)
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{
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$this->parser->getStream()->next();
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return $this->parseFilterExpressionRaw($node);
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}
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public function parseFilterExpressionRaw($node, $tag = null)
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{
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while (true) {
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$token = $this->parser->getStream()->expect(Twig_Token::NAME_TYPE);
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$name = new Twig_Node_Expression_Constant($token->getValue(), $token->getLine());
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if (!$this->parser->getStream()->test(Twig_Token::PUNCTUATION_TYPE, '(')) {
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$arguments = new Twig_Node();
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} else {
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$arguments = $this->parseArguments();
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}
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$node = new Twig_Node_Expression_Filter($node, $name, $arguments, $token->getLine(), $tag);
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if (!$this->parser->getStream()->test(Twig_Token::PUNCTUATION_TYPE, '|')) {
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break;
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}
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$this->parser->getStream()->next();
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}
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return $node;
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}
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public function parseArguments()
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{
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$args = array();
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$stream = $this->parser->getStream();
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$stream->expect(Twig_Token::PUNCTUATION_TYPE, '(', 'A list of arguments must be opened by a parenthesis');
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while (!$stream->test(Twig_Token::PUNCTUATION_TYPE, ')')) {
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if (!empty($args)) {
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$stream->expect(Twig_Token::PUNCTUATION_TYPE, ',', 'Arguments must be separated by a comma');
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}
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$args[] = $this->parseExpression();
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}
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$stream->expect(Twig_Token::PUNCTUATION_TYPE, ')', 'A list of arguments must be closed by a parenthesis');
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return new Twig_Node($args);
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}
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public function parseAssignmentExpression()
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{
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$targets = array();
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while (true) {
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$token = $this->parser->getStream()->expect(Twig_Token::NAME_TYPE, null, 'Only variables can be assigned to');
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if (in_array($token->getValue(), array('true', 'false', 'none'))) {
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throw new Twig_Error_Syntax(sprintf('You cannot assign a value to "%s"', $token->getValue()), $token->getLine());
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}
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$targets[] = new Twig_Node_Expression_AssignName($token->getValue(), $token->getLine());
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if (!$this->parser->getStream()->test(Twig_Token::PUNCTUATION_TYPE, ',')) {
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break;
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}
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$this->parser->getStream()->next();
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}
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return new Twig_Node($targets);
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}
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public function parseMultitargetExpression()
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{
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$targets = array();
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while (true) {
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$targets[] = $this->parseExpression();
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if (!$this->parser->getStream()->test(Twig_Token::PUNCTUATION_TYPE, ',')) {
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break;
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}
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$this->parser->getStream()->next();
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}
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return new Twig_Node($targets);
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}
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}
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