protected function callSnippetsInternal(array $source, $from)
    {
        $connection = $this->getConnection();
        $match = $this->match;
        if ($match === null) {
            throw new InvalidCallException('Unable to call snippets: "' . $this->className() . '::match" should be specified.');
        }

        return $connection->createCommand()
            ->callSnippets($from, $source, $match, $this->snippetOptions)
            ->queryColumn();
    }