Is there any sense of feature request for reader to return file type, or for loader to accept only those parameters that are accepted by reader?
If you believe that it would be a useful feature, there's no harm in raising it as a request.
It would be a lot easier for the IOFactory to detect the filetype (it's doing that already, though there's no built-in mechanism to retrieve the filetype detected) than to accept only those parameters that are accepted by reader
Sorry for offtopic, Is there any faster way to tell number of rows & cells ?
It takes me nearly same time to output highest row & col and draw a table with file contents using examples provided in manual.
$PHPExcelObject->getActiveSheet()->getHighestColumn() and $PHPExcelObject->getActiveSheet()->getHighestRow() might be what you're looking for.