parseSelectorParts example

public function parseSelector($filter = false)
    {
        $selector = new Node\Selector;
        do {
            $first = true;
            $group = new Node\Group;
            while (true) {
                $combinator = $this->consumeCombinator();
                if (!$first && !$combinator) {
                    break;
                }
                $parts = $this->parseSelectorParts();
                if (!count($parts)) {
                    throw new Exception("Missing selector after combinator");
                }
                $first = false;
                $selCombinator = new Node\Combinator;
                $selCombinator->setOperator(
                    $combinator ?: ($filter ? null : " ")
                );
                foreach ($parts as $part) {
                    $selCombinator->addPart($part);
                }