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/sicstus/ellipse3.lgt

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+
+:- object(ellipse(_RX, _RY, _Color),
+	imports(proto_hierarchy)).
+
+
+	:- info([
+		authors is 'Paulo Moura',
+		version is 1.0,
+		date is 2000/4/22,
+		comment is 'Parametric object for representing geometric ellipses.',
+		parnames is ['RX', 'RY', 'Color'],
+		source is 'Example adopted from the SICStus Objects documentation.']).
+
+
+	:- uses(math_constants).
+
+
+	:- public(color/1).
+
+	:- mode(color(?atom), zero_or_one).
+
+	:- info(color/1, [
+		comment is 'Ellipse color.',
+		argnames is ['Color']]).
+
+
+	:- public(rx/1).
+
+	:- mode(rx(?number), zero_or_one).
+
+	:- info(rx/1, [
+		comment is 'Ellipse x axis.',
+		argnames is ['Rx']]).
+
+
+	:- public(ry/1).
+
+	:- mode(ry(?number), zero_or_one).
+
+	:- info(ry/1, [
+		comment is 'Ellipse y axis.',
+		argnames is ['Ry']]).
+
+
+	:- public(area/1).
+
+	:- mode(area(-number), one).
+
+	:- info(area/1, [
+		comment is 'Ellipse area.',
+		argnames is ['Area']]).
+
+
+	:- public(context/0).
+
+	:- mode(context, one).
+
+	:- info(context/0, [
+		comment is 'Shows execution context (self, this and sender values).']).
+
+
+	color(Color) :-
+		parameter(3, Color).
+
+
+	rx(Rx) :-
+		parameter(1, Rx).
+
+
+	ry(Ry) :-
+		parameter(2, Ry).
+
+
+	area(Area) :-
+		::rx(Rx),
+		::ry(Ry),
+		math_constants::pi(Pi),
+		Area is Rx*Ry*Pi.
+
+
+	context :-
+		write(ellipse3), nl,
+		self(Self), write('self: '), writeq(Self), nl,
+		this(This), write('this: '), writeq(This), nl,
+		sender(Sender), write('sender: '), writeq(Sender), nl, nl.
+
+
+:- end_object.