Do you mean to check if all required field are filled, or some other form of validating the input?
In the latest version I did add a new operator you can use on a text or number field to validate the input with a custom function – see the help icon on the operator field of a rule.
Sorry, but there is no way to validate the validation settings set on a field in list settings from DFFS (other than to try to same and have SharePoint throw and error). If you like to control the validation from inside of DFFS you must set up the validation functions from DFFS itself.