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/bricks/brick.lgt

@@ -0,0 +1,76 @@
+
+:- object(brick,
+	instantiates(class),
+	specializes(object)).
+
+
+	:- info([
+		version is 1.1,
+		date is 2000/10/31,
+		authors is 'Paulo Moura',
+		comment is 'Two-dimensional brick (or should I say square?) class.']).
+
+
+	:- public(position/2).
+
+	:- mode(position(?integer, ?integer), zero_or_one).
+
+	:- info(position/2, [
+		comment is 'Brick current position.',
+		argnames is ['X', 'Y']]).
+
+
+	:- private(position_/2).
+	:- dynamic(position_/2).
+
+	:- mode(position_(?integer, ?integer), zero_or_one).
+
+	:- info(position_/2, [
+		comment is 'Stores brick current position.',
+		argnames is ['X', 'Y']]).
+
+
+	:- public(move/2).
+
+	:- mode(move(+integer, +integer), one).
+
+	:- info(move/2, [
+		comment is 'Moves a brick to a new position.',
+		argnames is ['X', 'Y']]).
+
+
+	position(X, Y) :-
+		::position_(X, Y).
+
+
+	move(X, Y) :-
+		::retractall(position_(_, _)),
+		::assertz(position_(X, Y)).
+
+
+	default_init_option(position-(0, 0)).
+
+	default_init_option(Default) :-
+		^^default_init_option(Default).
+
+
+	process_init_option(position-(X, Y)) :-
+		::assertz(position_(X, Y)).
+
+	process_init_option(Option) :-
+		^^process_init_option(Option).
+
+
+	valid_init_option(position-(X, Y)) :-
+		!,
+		integer(X),
+		integer(Y).
+
+	valid_init_option(Option) :-
+		^^valid_init_option(Option).
+
+
+	instance_base_name(b).
+
+
+:- end_object.