:- category(bounded_coordinate). :- info([ version is 1.0, date is 1998/3/23, author is 'Paulo Moura', comment is 'Point coordinate bounds management predicates.', source is 'Example adopted from the SICStus Objects documentation.']). :- public(set_bounds/3). :- mode(set_bounds(+atom, +integer, +integer), one). :- public(clear_bounds/1). :- mode(clear_bounds(+atom), one). :- public(bounds/3). :- mode(bounds(?atom, ?integer, ?integer), zero_or_more). :- public(check_bounds/2). :- mode(check_bounds(+atom, +integer), zero_or_one). :- public(print_bounds/1). :- mode(print_bounds(?atom), zero_or_more). :- public(valid_value/2). :- mode(valid_value(+atom, +integer), zero_or_one). :- private(bounds_/3). :- dynamic(bounds_/3). :- mode(bounds_(?atom, ?integer, ?integer), zero_or_more). set_bounds(Coordinate, Min, Max) :- ::retractall(bounds_(Coordinate, _, _)), ::assertz(bounds_(Coordinate, Min, Max)). clear_bounds(Coordinate) :- ::retractall(bounds_(Coordinate, _, _)). bounds(Coordinate, Min, Max) :- ::bounds_(Coordinate, Min, Max). check_bounds(Coordinate, Value) :- ::bounds_(Coordinate, Min, Max), Value >= Min, Value =< Max. print_bounds(Coordinate) :- ::bounds_(Coordinate, Min, Max), writeq(bounds(Coordinate)), write(' : '), write((Min, Max)), nl. valid_value(Coordinate, Value) :- ::bounds_(Coordinate, Min, Max) -> Value >= Min, Value =< Max ; true. :- end_category.