PhpCss\Ast\Visitor\Xpath::visitEnterSelectorSimplePseudoClass PHP Метод

    public function visitEnterSelectorSimplePseudoClass(Ast\Selector\Simple\PseudoClass $pseudoClass)
    {
        switch ($pseudoClass->name) {
            case 'not':
                $this->addCondition('not(');
                $this->status(self::STATUS_PSEUDOCLASS);
                return TRUE;
            case 'nth-child':
                $this->addCondition('(');
                $this->status(self::STATUS_PSEUDOCLASS);
                $this->_expressions['position'] = 'position()';
                $this->_expressions['count'] = 'last()';
                return TRUE;
            case 'nth-last-child':
                $this->addCondition('(');
                $this->status(self::STATUS_PSEUDOCLASS);
                $this->_expressions['position'] = '(last() - position() + 1)';
                $this->_expressions['count'] = 'count()';
                return TRUE;
            case 'nth-of-type':
                $this->addCondition('(');
                $this->status(self::STATUS_PSEUDOCLASS);
                $this->_expressions['position'] = '(count(preceding-sibling::' . $this->_element . ') + 1)';
                $this->_expressions['count'] = 'count(parent::*/' . $this->_element . ')';
                return TRUE;
            case 'nth-last-of-type':
                $this->addCondition('(');
                $this->status(self::STATUS_PSEUDOCLASS);
                $this->_expressions['position'] = '(count(following-sibling::' . $this->_element . ') + 1)';
                $this->_expressions['count'] = 'count(parent::*/' . $this->_element . ')';
                return TRUE;
        }
        return FALSE;
    }