protected function replaceParentBlock($savedContent)
    {
       $pattern = sprintf(self::TMPL_RENDER_PARENT, "([^']+)", "([^|]+)");
       $result = preg_match("/{$pattern}/", $savedContent, $matches);
       if (!$result) {
           return $savedContent;
       } else { // processing parentBlock()
           $fullBlockName = $matches[1];
           $viewFileName = $matches[2];
           $replacement = $this->findParentBlock($fullBlockName, $viewFileName);
           $out = preg_replace("/{$pattern}/", $replacement, $savedContent);
           return $out;
       }
    }