308 lines
9.8 KiB
PHP
308 lines
9.8 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.potencier@symfony-project.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\CssSelector;
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/**
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* Parser is the main entry point of the component and can convert CSS
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* selectors to XPath expressions.
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*
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* $xpath = Parser::cssToXpath('h1.foo');
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*
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* This component is a port of the Python lxml library,
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* which is copyright Infrae and distributed under the BSD license.
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*
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* @author Fabien Potencier <fabien.potencier@symfony-project.com>
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*/
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class Parser
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{
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/**
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* Translates a CSS expression to its XPath equivalent.
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* Optionally, a prefix can be added to the resulting XPath
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* expression with the $prefix parameter.
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*
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* @throws SyntaxError When got None for xpath expression
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*
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* @param mixed $cssExpr The CSS expression.
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* @param string $prefix An optional prefix for the XPath expression.
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*
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* @return string
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*/
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static public function cssToXpath($cssExpr, $prefix = 'descendant-or-self::')
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{
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if (is_string($cssExpr)) {
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if (preg_match('#^\w+\s*$#u', $cssExpr, $match)) {
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return $prefix.trim($match[0]);
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}
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if (preg_match('~^(\w*)#(\w+)\s*$~u', $cssExpr, $match)) {
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return sprintf("%s%s[@id = '%s']", $prefix, $match[1] ? $match[1] : '*', $match[2]);
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}
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if (preg_match('#^(\w*)\.(\w+)\s*$#u', $cssExpr, $match)) {
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return sprintf("%s%s[contains(concat(' ', normalize-space(@class), ' '), ' %s ')]", $prefix, $match[1] ? $match[1] : '*', $match[2]);
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}
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$parser = new self();
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$cssExpr = $parser->parse($cssExpr);
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}
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$expr = $cssExpr->toXpath();
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// @codeCoverageIgnoreStart
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if (!$expr) {
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throw new SyntaxError(sprintf('Got None for xpath expression from %s.', $cssExpr));
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}
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// @codeCoverageIgnoreEnd
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if ($prefix) {
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$expr->addPrefix($prefix);
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}
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return (string) $expr;
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}
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/**
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* Parses an expression and returns the Node object that represents
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* the parsed expression.
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*
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* @throws \Exception When tokenizer throws it while parsing
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*
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* @param string $string The expression to parse
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*
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* @return Node\NodeInterface
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*/
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public function parse($string)
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{
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$tokenizer = new Tokenizer();
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$stream = new TokenStream($tokenizer->tokenize($string), $string);
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try {
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return $this->parseSelectorGroup($stream);
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} catch (\Exception $e) {
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$class = get_class($e);
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throw new $class(sprintf('%s at %s -> %s', $e->getMessage(), implode($stream->getUsed(), ''), $stream->peek()), 0, $e);
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}
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}
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/**
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* Parses a selector group contained in $stream and returns
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* the Node object that represents the expression.
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*
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* @param TokenStream $stream The stream to parse.
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*
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* @return Node\NodeInterface
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*/
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protected function parseSelectorGroup($stream)
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{
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$result = array();
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while (true) {
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$result[] = $this->parseSelector($stream);
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if ($stream->peek() == ',') {
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$stream->next();
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} else {
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break;
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}
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}
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if (count($result) == 1) {
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return $result[0];
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}
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return new Node\OrNode($result);
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}
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/**
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* Parses a selector contained in $stream and returns the Node
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* object that represents it.
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*
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* @throws SyntaxError When expected selector but got something else
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*
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* @param TokenStrem $stream The stream containing the selector.
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*
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* @return Node\NodeInterface
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*/
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protected function parseSelector($stream)
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{
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$result = $this->parseSimpleSelector($stream);
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while (true) {
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$peek = $stream->peek();
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if (',' == $peek || null === $peek) {
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return $result;
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} elseif (in_array($peek, array('+', '>', '~'))) {
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// A combinator
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$combinator = (string) $stream->next();
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} else {
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$combinator = ' ';
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}
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$consumed = count($stream->getUsed());
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$next_selector = $this->parseSimpleSelector($stream);
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if ($consumed == count($stream->getUsed())) {
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throw new SyntaxError(sprintf("Expected selector, got '%s'", $stream->peek()));
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}
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$result = new Node\CombinedSelectorNode($result, $combinator, $next_selector);
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}
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return $result;
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}
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/**
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* Parses a simple selector (the current token) from $stream and returns
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* the resulting Node object.
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*
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* @throws SyntaxError When expected symbol but got something else
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*
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* @param TokenStream The stream containing the selector.
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*
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* @return Node\NodeInterface
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*/
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protected function parseSimpleSelector($stream)
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{
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$peek = $stream->peek();
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if ('*' != $peek && !$peek->isType('Symbol')) {
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$element = $namespace = '*';
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} else {
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$next = $stream->next();
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if ('*' != $next && !$next->isType('Symbol')) {
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throw new SyntaxError(sprintf("Expected symbol, got '%s'", $next));
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}
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if ($stream->peek() == '|') {
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$namespace = $next;
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$stream->next();
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$element = $stream->next();
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if ('*' != $element && !$next->isType('Symbol')) {
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throw new SyntaxError(sprintf("Expected symbol, got '%s'", $next));
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}
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} else {
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$namespace = '*';
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$element = $next;
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}
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}
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$result = new Node\ElementNode($namespace, $element);
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$has_hash = false;
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while (true) {
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$peek = $stream->peek();
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if ('#' == $peek) {
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if ($has_hash) {
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/* You can't have two hashes
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(FIXME: is there some more general rule I'm missing?) */
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// @codeCoverageIgnoreStart
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break;
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// @codeCoverageIgnoreEnd
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}
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$stream->next();
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$result = new Node\HashNode($result, $stream->next());
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$has_hash = true;
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continue;
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} elseif ('.' == $peek) {
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$stream->next();
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$result = new Node\ClassNode($result, $stream->next());
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continue;
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} elseif ('[' == $peek) {
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$stream->next();
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$result = $this->parseAttrib($result, $stream);
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$next = $stream->next();
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if (']' != $next) {
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throw new SyntaxError(sprintf("] expected, got '%s'", $next));
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}
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continue;
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} elseif (':' == $peek || '::' == $peek) {
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$type = $stream->next();
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$ident = $stream->next();
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if (!$ident || !$ident->isType('Symbol')) {
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throw new SyntaxError(sprintf("Expected symbol, got '%s'", $ident));
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}
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if ($stream->peek() == '(') {
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$stream->next();
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$peek = $stream->peek();
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if ($peek->isType('String')) {
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$selector = $stream->next();
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} elseif ($peek->isType('Symbol') && is_int($peek)) {
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$selector = intval($stream->next());
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} else {
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// FIXME: parseSimpleSelector, or selector, or...?
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$selector = $this->parseSimpleSelector($stream);
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}
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$next = $stream->next();
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if (')' != $next) {
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throw new SyntaxError(sprintf("Expected ')', got '%s' and '%s'", $next, $selector));
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}
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$result = new Node\FunctionNode($result, $type, $ident, $selector);
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} else {
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$result = new Node\PseudoNode($result, $type, $ident);
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}
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continue;
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} else {
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if (' ' == $peek) {
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$stream->next();
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}
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break;
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}
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// FIXME: not sure what "negation" is
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}
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return $result;
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}
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/**
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* Parses an attribute from a selector contained in $stream and returns
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* the resulting AttribNode object.
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*
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* @throws SyntaxError When encountered unexpected selector
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*
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* @param Node\NodeInterface $selector The selector object whose attribute
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* is to be parsed.
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* @param TokenStream $strem The container token stream.
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*
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* @return Node\AttribNode
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*/
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protected function parseAttrib($selector, $stream)
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{
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$attrib = $stream->next();
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if ($stream->peek() == '|') {
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$namespace = $attrib;
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$stream->next();
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$attrib = $stream->next();
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} else {
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$namespace = '*';
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}
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if ($stream->peek() == ']') {
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return new Node\AttribNode($selector, $namespace, $attrib, 'exists', null);
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}
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$op = $stream->next();
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if (!in_array($op, array('^=', '$=', '*=', '=', '~=', '|=', '!='))) {
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throw new SyntaxError(sprintf("Operator expected, got '%s'", $op));
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}
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$value = $stream->next();
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if (!$value->isType('Symbol') && !$value->isType('String')) {
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throw new SyntaxError(sprintf("Expected string or symbol, got '%s'", $value));
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}
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return new Node\AttribNode($selector, $namespace, $attrib, $op, $value);
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}
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}
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