% briefcase world (June,1999)
% --------------------------------------------------

sorts(primitive_sorts,[bag, thing, place]).

objects(bag, [briefcase, suitcase]).
objects(thing, [cheque, suit, dictionary]).
objects(place, [home,office]).

implied_invariant([],[]).

predicates([
 at_bag(bag,place), 
 at_thing(thing,place),
 inside(thing,bag),
 outside(thing),
 fits_in(thing,bag)] ).

atomic_invariants( [ fits_in(cheque,briefcase),
                     fits_in(dictionary,briefcase),
                     fits_in(cheque,suitcase),
                     fits_in(dictionary,suitcase),
                     fits_in(suit,suitcase)   ]).

substate_classes(bag,Bag,[
	         [at_bag(Bag,Place)] ]). 	

substate_classes(thing, Thing,[
      [at_thing(Thing,Place), inside(Thing,Bag), fits_in(Thing,Bag)],
      [at_thing(Thing,Place),outside(Thing)] ]).

inconsistent_constraint([at_bag(X,P),at_bag(X,R),ne(P,R)]).
inconsistent_constraint([at_thing(X,P),at_thing(X,R),ne(P,R)]).
inconsistent_constraint([inside(Thing,B),inside(Thing,B1),ne(B,B1)]).
inconsistent_constraint([inside(Thing,B),outside(Thing)]).
inconsistent_constraint([inside(T,B),at_bag(B,P),at_thing(T,P1),ne(P1,P)]).

operator(move(X,A,B), 
     % prevail
     [],
     % necessary
     [sc(bag,X,[at_bag(X,A),ne(A,B)]=>[at_bag(X,B)]) ],
     % conditional
     [sc(thing,T,[at_thing(T,A), inside(T,X), fits_in(T,X)]=>
         [at_thing(T,B), inside(T,X)]) ]  
      ).

operator(put_in(T,X), 
     % prevail
     [se(bag,X, [at_bag(X,A)])],
     % necessary
     [sc(thing,T,[at_thing(T,A),outside(T)]=>
         [at_thing(T,A), inside(T,X), fits_in(T,X)]) ],
     % conditional
     []) .

operator(take_out(T,X), 
     % prevail
     [se(bag,X,[at_bag(X,A)])],
     % necessary
     [sc(thing,T,[at_thing(T,A),inside(T,X) ]=>
         [at_thing(T,A),outside(T)])],
     % conditional
     []) .