% Rocket World (June, 1999)
% -------------------------------------------------

sorts(primitive_sorts,[rocket, location, cargo]).

objects(rocket, [r1,r2]).
objects(cargo, [c1, c2, c3, c4]).
objects(location, [london,paris,jfk]).

predicates([
 at(cargo,location), 
 position(rocket,location),
 fuel_empty(rocket),
 fuel_full(rocket),
 in(cargo,rocket)] ).

atomic_invariants( [ ]).

substate_classes(cargo,Cargo,[
	[at(Cargo,Loc)], 
        [in(Cargo,Roc)]  ] ). 	

substate_classes(rocket,R, [
      [position(R,Loc), fuel_empty(R)],
      [position(R,Loc), fuel_full(R)] ]).

implied_invariant([],[]).

inconsistent_constraint([at(X,P),at(X,R),ne(P,R)]).
inconsistent_constraint([position(X,P),position(X,R),ne(P,R)]).
inconsistent_constraint([at(C,L1),at(C,L2),ne(L1,L2)]).
inconsistent_constraint([in(C,R),in(C,R1),ne(R,R1)]).
inconsistent_constraint([fuel_empty(R),fuel_full(R)]).

operator(move(R,A,B), 
     % prevail
     [],
     % necessary
     [sc(rocket,R,[position(R,A), fuel_full(R), ne(A,B)]=>
	            [position(R,B), fuel_empty(R)])
     ],
     % conditional
     []).

operator(load(C,R,A), 
     % prevail
     [se(rocket,R,[position(R,A)])],
     % necessary
     [sc(cargo,C,[at(C,A)]=>[in(C,R)])],
     % conditional
     []) .

operator(unload(C,R,A), 
     % prevail
     [se(rocket,R,[position(R,A)])],
     % necessary
     [sc(cargo,C,[in(C,R)]=>[at(C,A)])],
     % conditional
     []) .