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1 1686 darkviper
<?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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 */
24
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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                $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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            case Twig_Token::STRING_TYPE:
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            case Twig_Token::INTERPOLATION_START_TYPE:
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                $node = $this->parseStringExpression();
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                break;
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            default:
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                if ($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(), $this->parser->getFilename());
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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 parseStringExpression()
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    {
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        $stream = $this->parser->getStream();
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        $nodes = array();
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        // a string cannot be followed by another string in a single expression
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        $nextCanBeString = true;
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        while (true) {
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            if ($stream->test(Twig_Token::STRING_TYPE) && $nextCanBeString) {
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                $token = $stream->next();
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                $nodes[] = new Twig_Node_Expression_Constant($token->getValue(), $token->getLine());
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                $nextCanBeString = false;
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            } elseif ($stream->test(Twig_Token::INTERPOLATION_START_TYPE)) {
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                $stream->next();
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                $nodes[] = $this->parseExpression();
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                $stream->expect(Twig_Token::INTERPOLATION_END_TYPE);
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                $nextCanBeString = true;
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            } else {
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                break;
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            }
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        }
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        $expr = array_shift($nodes);
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        foreach ($nodes as $node) {
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            $expr = new Twig_Node_Expression_Binary_Concat($expr, $node, $node->getLine());
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        }
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        return $expr;
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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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        $node = new Twig_Node_Expression_Array(array(), $stream->getCurrent()->getLine());
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        $first = true;
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        while (!$stream->test(Twig_Token::PUNCTUATION_TYPE, ']')) {
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            if (!$first) {
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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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            $first = false;
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            $node->addElement($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 $node;
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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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        $node = new Twig_Node_Expression_Array(array(), $stream->getCurrent()->getLine());
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        $first = true;
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        while (!$stream->test(Twig_Token::PUNCTUATION_TYPE, '}')) {
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            if (!$first) {
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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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            $first = false;
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            // a hash key can be:
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            //
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            //  * a number -- 12
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            //  * a string -- 'a'
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            //  * a name, which is equivalent to a string -- a
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            //  * an expression, which must be enclosed in parentheses -- (1 + 2)
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            if ($stream->test(Twig_Token::STRING_TYPE) || $stream->test(Twig_Token::NAME_TYPE) || $stream->test(Twig_Token::NUMBER_TYPE)) {
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                $token = $stream->next();
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                $key = new Twig_Node_Expression_Constant($token->getValue(), $token->getLine());
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            } elseif ($stream->test(Twig_Token::PUNCTUATION_TYPE, '(')) {
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                $key = $this->parseExpression();
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            } else {
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                $current = $stream->getCurrent();
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                throw new Twig_Error_Syntax(sprintf('A hash key must be a quoted string, a number, a name, or an expression enclosed in parentheses (unexpected token "%s" of value "%s"', Twig_Token::typeToEnglish($current->getType(), $current->getLine()), $current->getValue()), $current->getLine(), $this->parser->getFilename());
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            }
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            $stream->expect(Twig_Token::PUNCTUATION_TYPE, ':', 'A hash key must be followed by a colon (:)');
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            $value = $this->parseExpression();
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            $node->addElement($value, $key);
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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 $node;
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    }
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    public function parsePostfixExpression($node)
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    {
270
        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 $node;
286
    }
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    public function getFunctionNode($name, $line)
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    {
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        $args = $this->parseArguments();
291
        switch ($name) {
292
            case 'parent':
293
                if (!count($this->parser->getBlockStack())) {
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                    throw new Twig_Error_Syntax('Calling "parent" outside a block is forbidden', $line, $this->parser->getFilename());
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                }
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                if (!$this->parser->getParent() && !$this->parser->hasTraits()) {
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                    throw new Twig_Error_Syntax('Calling "parent" on a template that does not extend nor "use" another template is forbidden', $line, $this->parser->getFilename());
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                }
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                return new Twig_Node_Expression_Parent($this->parser->peekBlockStack(), $line);
302
            case 'block':
303
                return new Twig_Node_Expression_BlockReference($args->getNode(0), false, $line);
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            case 'attribute':
305
                if (count($args) < 2) {
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                    throw new Twig_Error_Syntax('The "attribute" function takes at least two arguments (the variable and the attributes)', $line, $this->parser->getFilename());
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                }
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                return new Twig_Node_Expression_GetAttr($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:
311 1852 darkviper
                if (null !== $alias = $this->parser->getImportedSymbol('function', $name)) {
312 1686 darkviper
                    $arguments = new Twig_Node_Expression_Array(array(), $line);
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                    foreach ($args as $n) {
314
                        $arguments->addElement($n);
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                    }
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                    $node = new Twig_Node_Expression_MethodCall($alias['node'], $alias['name'], $arguments, $line);
318
                    $node->setAttribute('safe', true);
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                    return $node;
321
                }
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                $class = $this->getFunctionNodeClass($name);
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325
                return new $class($name, $args, $line);
326
        }
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    }
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    public function parseSubscriptExpression($node)
330
    {
331
        $stream = $this->parser->getStream();
332
        $token = $stream->next();
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        $lineno = $token->getLine();
334
        $arguments = new Twig_Node_Expression_Array(array(), $lineno);
335
        $type = Twig_TemplateInterface::ANY_CALL;
336
        if ($token->getValue() == '.') {
337
            $token = $stream->next();
338
            if (
339
                $token->getType() == Twig_Token::NAME_TYPE
340
                ||
341
                $token->getType() == Twig_Token::NUMBER_TYPE
342
                ||
343
                ($token->getType() == Twig_Token::OPERATOR_TYPE && preg_match(Twig_Lexer::REGEX_NAME, $token->getValue()))
344
            ) {
345
                $arg = new Twig_Node_Expression_Constant($token->getValue(), $lineno);
346
347
                if ($stream->test(Twig_Token::PUNCTUATION_TYPE, '(')) {
348
                    $type = Twig_TemplateInterface::METHOD_CALL;
349
                    foreach ($this->parseArguments() as $n) {
350
                        $arguments->addElement($n);
351
                    }
352
                }
353
            } else {
354 1852 darkviper
                throw new Twig_Error_Syntax('Expected name or number', $lineno, $this->parser->getFilename());
355 1686 darkviper
            }
356
        } else {
357
            $type = Twig_TemplateInterface::ARRAY_CALL;
358
359
            $arg = $this->parseExpression();
360
361
            // slice?
362
            if ($stream->test(Twig_Token::PUNCTUATION_TYPE, ':')) {
363
                $stream->next();
364
365
                if ($stream->test(Twig_Token::PUNCTUATION_TYPE, ']')) {
366
                    $length = new Twig_Node_Expression_Constant(null, $token->getLine());
367
                } else {
368
                    $length = $this->parseExpression();
369
                }
370
371
                $class = $this->getFilterNodeClass('slice');
372
                $arguments = new Twig_Node(array($arg, $length));
373
                $filter = new $class($node, new Twig_Node_Expression_Constant('slice', $token->getLine()), $arguments, $token->getLine());
374
375
                $stream->expect(Twig_Token::PUNCTUATION_TYPE, ']');
376
377
                return $filter;
378
            }
379
380
            $stream->expect(Twig_Token::PUNCTUATION_TYPE, ']');
381
        }
382
383 1852 darkviper
        if ($node instanceof Twig_Node_Expression_Name && null !== $alias = $this->parser->getImportedSymbol('template', $node->getAttribute('name'))) {
384
            $node = new Twig_Node_Expression_MethodCall($node, 'get'.$arg->getAttribute('value'), $arguments, $lineno);
385
            $node->setAttribute('safe', true);
386
387
            return $node;
388
        }
389
390 1686 darkviper
        return new Twig_Node_Expression_GetAttr($node, $arg, $arguments, $type, $lineno);
391
    }
392
393
    public function parseFilterExpression($node)
394
    {
395
        $this->parser->getStream()->next();
396
397
        return $this->parseFilterExpressionRaw($node);
398
    }
399
400
    public function parseFilterExpressionRaw($node, $tag = null)
401
    {
402
        while (true) {
403
            $token = $this->parser->getStream()->expect(Twig_Token::NAME_TYPE);
404
405
            $name = new Twig_Node_Expression_Constant($token->getValue(), $token->getLine());
406
            if (!$this->parser->getStream()->test(Twig_Token::PUNCTUATION_TYPE, '(')) {
407
                $arguments = new Twig_Node();
408
            } else {
409
                $arguments = $this->parseArguments();
410
            }
411
412
            $class = $this->getFilterNodeClass($name->getAttribute('value'));
413
414
            $node = new $class($node, $name, $arguments, $token->getLine(), $tag);
415
416
            if (!$this->parser->getStream()->test(Twig_Token::PUNCTUATION_TYPE, '|')) {
417
                break;
418
            }
419
420
            $this->parser->getStream()->next();
421
        }
422
423
        return $node;
424
    }
425
426
    public function parseArguments()
427
    {
428
        $args = array();
429
        $stream = $this->parser->getStream();
430
431
        $stream->expect(Twig_Token::PUNCTUATION_TYPE, '(', 'A list of arguments must be opened by a parenthesis');
432
        while (!$stream->test(Twig_Token::PUNCTUATION_TYPE, ')')) {
433
            if (!empty($args)) {
434
                $stream->expect(Twig_Token::PUNCTUATION_TYPE, ',', 'Arguments must be separated by a comma');
435
            }
436
            $args[] = $this->parseExpression();
437
        }
438
        $stream->expect(Twig_Token::PUNCTUATION_TYPE, ')', 'A list of arguments must be closed by a parenthesis');
439
440
        return new Twig_Node($args);
441
    }
442
443
    public function parseAssignmentExpression()
444
    {
445
        $targets = array();
446
        while (true) {
447
            $token = $this->parser->getStream()->expect(Twig_Token::NAME_TYPE, null, 'Only variables can be assigned to');
448
            if (in_array($token->getValue(), array('true', 'false', 'none'))) {
449 1852 darkviper
                throw new Twig_Error_Syntax(sprintf('You cannot assign a value to "%s"', $token->getValue()), $token->getLine(), $this->parser->getFilename());
450 1686 darkviper
            }
451
            $targets[] = new Twig_Node_Expression_AssignName($token->getValue(), $token->getLine());
452
453
            if (!$this->parser->getStream()->test(Twig_Token::PUNCTUATION_TYPE, ',')) {
454
                break;
455
            }
456
            $this->parser->getStream()->next();
457
        }
458
459
        return new Twig_Node($targets);
460
    }
461
462
    public function parseMultitargetExpression()
463
    {
464
        $targets = array();
465
        while (true) {
466
            $targets[] = $this->parseExpression();
467
            if (!$this->parser->getStream()->test(Twig_Token::PUNCTUATION_TYPE, ',')) {
468
                break;
469
            }
470
            $this->parser->getStream()->next();
471
        }
472
473
        return new Twig_Node($targets);
474
    }
475
476
    protected function getFunctionNodeClass($name)
477
    {
478
        $functionMap = $this->parser->getEnvironment()->getFunctions();
479
        if (isset($functionMap[$name]) && $functionMap[$name] instanceof Twig_Function_Node) {
480
            return $functionMap[$name]->getClass();
481
        }
482
483
        return 'Twig_Node_Expression_Function';
484
    }
485
486
    protected function getFilterNodeClass($name)
487
    {
488
        $filterMap = $this->parser->getEnvironment()->getFilters();
489
        if (isset($filterMap[$name]) && $filterMap[$name] instanceof Twig_Filter_Node) {
490
            return $filterMap[$name]->getClass();
491
        }
492
493
        return 'Twig_Node_Expression_Filter';
494
    }
495
}