Wish: support for IAggregatable for NextrasDataSource

[milsorm]

Is it possible to add support for IAggregatable also for NextrasDataSource? I am using Nextras ORM with this datagrid and that implementation (which looks like one function only) is missing.

Thanks a lot in advance.

[milsorm]

NextrasDataSource.php:

    /**
     * @param  IAggregationFunction $function
     * @return void
     */
     public function processAggregation(IAggregationFunction $function): void
     {
         $function->processDataSource(clone $this->dataSource);
     }

FunctionSum.php::processDataSource at the end new style:

        if ( $dataSource instanceof DbalCollection) {
            foreach( $dataSource->fetchAll() as $item )
                $this->result += $item->getValue( $this->column );
        }

[paveljanda]

It looks like you know what you're doing - could you prepare a PR?

[milsorm]

Prepared #968