fix cargo example

examples/logistics/encoding.lp

@@ -18,32 +18,36 @@ at(A,L) :- 'at(A,L), not -at(A,L), _airplane(A).
 at(P,L) :- 'at(P,L), not -at(P,L), _package(P).
 -at(P,L) :- at(P,M), _location(L), L!=M, _package(P).
 
-%%%%%%%%%%% Loading objects / unloading objects
+%%%%%%%%%%% Loading objects
 
-loaded(P) :- in(P,V).
+{ load(P,V) } :- _package(P), 'at(P,L), _vehicle(V), 'at(V,L), not 'in(P,V), not 'loaded(P).
+:- { load(P,V) } > 1, _package(P).
 
-can_load(P,V) :- _package(P), 'at(P,L), _vehicle(V), 'at(V,L), not 'in(P,V), not 'loaded(P).
 in(P,V) :- load(P,V).
+loaded(P) :- in(P,V).
+
+%%%%%%%%%%% Unloading objects
 
-can_unload(P,V) :- _package(P), 'in(P,V).
+{ unload(P,V) } :- _package(P), 'in(P,V).
 
 % Frame axiom for "in"
 in(P,V) :- 'in(P,V), not unload(P,V).
 
 %%%%%%%%%%% Moving vehicles
 
-can_move(T,L) :- _truck(T), 'at(T,M), _in_city(M,C), _in_city(L,C), L!=M.
-can_move(A,L) :- _airplane(A), 'at(A,M), _airport(L), L!=M.
-at(V,L) :- move(V,L).
-moved(V) :- move(V,_).
+{ move(T,L) } :- _truck(T), 'at(T,M), _in_city(M,C), _in_city(L,C), L!=M.
+{ move(A,L) } :- _airplane(A), 'at(A,M), _airport(L), L!=M.
+:- { move(V,L) } > 1, _vehicle(V).
 
-{load(P,V):can_load(P,V); unload(P,V): can_unload(P,V) } :- _vehicle(V).
 cargo(V) :- load(P,V).
 cargo(V) :- unload(P,V).
-0 {move(V,L): can_move(V,L)} 1 :-  _vehicle(V), not cargo(V).
+:- move(V,L), cargo(V).
+
+at(V,L) :- move(V,L).
+moved(V) :- move(V,_).
 
 #program always.
-%:- at(O,L), at(O,M), L!=M.
+
 at(P,L) :- in(P,V), at(V,L).
 
 % Control rule: if we move a vehicle, it keeps unmoved until some cargo is done
@@ -53,4 +57,10 @@ at(P,L) :- in(P,V), at(V,L).
 :- _goal_at(P,L), not at(P,L), not _testing.
 :- _goal_at(P,L), loaded(P),   not _testing.
 
-
+#defined in/3.
+#defined load/3.
+#defined loaded/2.
+#defined move/3.
+#defined moved/2.
+#defined testing/1.
+#defined unload/3.