Flow\Parser::parseXorExpression PHP Method

    protected function parseXorExpression()
    {
        $line = $this->stream->getCurrentToken()->getLine();
        $left = $this->parseOrExpression();
        while ($this->stream->consume(Token::OPERATOR, 'xor')) {
            $right = $this->parseOrExpression();
            $left = new Expression\XorExpression($left, $right, $line);
            $line = $this->stream->getCurrentToken()->getLine();
        }
        return $left;
    }