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/lpa/fault.lgt

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+
+:- object(fault,
+	imports(proto_hierarchy)).
+
+
+	:- info([
+		authors is 'Paulo Moura',
+		version is 1.0,
+		date is 2000/4/22,
+		comment is 'Expert system for automobile fault diagnosis.',
+		source is 'Example adopted from the LPA Prolog++ documentation.']).
+
+
+	:- public(findall/0).
+	:- mode(findall, one).
+
+	:- private(told_by_user_/2).
+	:- dynamic(told_by_user_/2).
+	:- mode(told_by_user_(?nonvar, ?nonvar), zero_or_more).
+
+	:- public(find/1).
+	:- mode(find(?nonvar), zero_or_more).
+
+	:- private(exhibited/1).
+	:- mode(exhibited(+nonvar), zero_or_one).
+
+	:- public(contrary/2).
+	:- mode(contrary(?nonvar, ?nonvar), zero_or_more).
+
+	:- public(fault/2).
+	:- mode(fault(?nonvar, ?nonvar), zero_or_more).
+
+	:- public(effect/2).
+	:- mode(effect(?nonvar, ?nonvar), zero_or_more).
+
+	:- public(symptom/2).
+	:- mode(symptom(?nonvar, ?nonvar), zero_or_more).
+
+
+	findall :-
+		retractall(told_by_user_(_, _)),
+		write('Please answer all questions with yes or no.'), nl, nl,
+		forall(
+ 			(::descendant(Where), Where::find(Description)),
+			(nl, write('Location      : '), write(Where), nl,
+			 write('Possible Fault: '), write(Description), nl)),
+		nl, write('No (more) explanations found.').
+
+
+	find(Description) :-
+		::fault(Fault, Description),
+		forall(::effect(Fault, Symptom), exhibited(Symptom)).
+
+
+	exhibited(Symptom) :-
+		told_by_user_(Symptom, Reply),
+		!,
+		Reply = yes.
+
+	exhibited(Symptom) :-
+		::symptom(Symptom, Description),
+		write(Description), write('? '),
+		read(Reply),
+		asserta(told_by_user_(Symptom, Reply)),
+		Reply = yes,
+		forall(
+			(::contrary(Symptom, Contrary);
+			 ::contrary(Contrary, Symptom)),
+			asserta(told_by_user_(Contrary, no))).
+
+
+:- end_object.