:- object(red_circle(Radius), extends(circle(Radius, red))). :- info([ author is 'Paulo Moura', version is 1.0, date is 2000/4/22, comment is 'Parametric object for representing geometric red circles.', parnames is ['Radius'], source is 'Example adopted from the SICStus Objects documentation.']). context :- write(red_circle1), nl, self(Self), write('self: '), writeq(Self), nl, this(This), write('this: '), writeq(This), nl, sender(Sender), write('sender: '), writeq(Sender), nl, nl, ^^context. :- end_object.