Include Paulo Moura's Logtalk OO LP system

git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@53 b08c6af1-5177-4d33-ba66-4b1c6b8b522a

Logtalk/examples/points/bounded_coordinate.lgt

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+
+:- category(bounded_coordinate).
+
+
+	:- info([
+		version is 1.0,
+		date is 1998/3/23,
+		authors 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.