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/searching/depth_first1.lgt

@@ -0,0 +1,33 @@
+
+:- object(depth_first(Bound),
+	instantiates(blind_search(Bound))).
+
+
+	:- info([
+		version is 1.0,
+		authors is 'Paulo Moura',
+		date is 1998/3/23,
+		comment is 'Depth first state space search strategy.',
+		parnames is ['Bound']]).
+
+
+	:- uses(list).
+
+
+	search(Space, State, Bound, Solution) :-
+		depth(Space, State, Bound, [], Path),
+		list::reverse(Path, Solution).
+
+
+	depth(Space, State, _, Path, [State| Path]) :-
+		Space::goal_state(State).
+
+	depth(Space, State, Bound, Path, Solution) :-
+		Bound > 0,
+		Space::next_state(State, Next),
+		\+ list::member(Next, [State| Path]),
+		Bound2 is Bound - 1,
+		depth(Space, Next, Bound2, [State| Path], Solution).
+
+
+:- end_object.