No, but in master (i.e. unreleased) if you defined dependent enumerations and one value of a parent doesn't have a dependent enumeration defined it falls back to show a widget for the underlying data-type.
For example:-
Car.fuel = ["Diesel", "Petrol"]
Car[fuel=Diesel] = ["BIO", "REGULAR"]
Selecting Car, Fuel=Diesel would show a list box for "BIO" and "REGULAR".
Selecting Car, Fuel=Petrol would show a text box.
If you use a template or decision table and leave the textbox empty the constraint will not be included in the resulting DRL.