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plasp/encodings/pddl-sequential-horizon-boolean.lp

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#const horizon=1.
step(0..horizon).
precondition(Action,variable(Fluent),Value) :- precondition(Action, variable(Fluent),value(Fluent,Value)).
postcondition(Action,variable(Fluent),Value) :- postcondition(Action,effect(unconditional),variable(Fluent),value(Fluent,Value)).
holds(variable(Fluent),0) :- initialState(variable(Fluent),value(Fluent,true)).
{ occurs(Action,T) : action(Action) } = 1 :- step(T), T>0.
:- occurs(Action,T), precondition(Action,Fluent,true), not holds(Fluent,T-1).
:- occurs(Action,T), precondition(Action,Fluent,false), holds(Fluent,T-1).
caused(Fluent,T) :- occurs(Action,T), postcondition(Action,Fluent,true).
holds(Fluent,T) :- caused(Fluent,T).
holds(Fluent,T) :- holds(Fluent,T-1), not occurs(Action,T) : postcondition(Action,Fluent,false); T<=horizon.
goalAt(T) :- holds(variable(Variable),T) : goal(variable(Variable), value(Variable,true));
not holds(variable(Variable),T) : goal(variable(Variable), value(Variable,false));
T=horizon.
:- not goalAt(horizon).
#show occurs/2.
% #show holds/2.