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