/// This method applies an Action to a WorldState in reverse. In effect,
/// it determines the state of the world required that when this Action is
/// applied to it, the result is the current state.
/// This involves making sure that the new state's predicates match the
/// Action's prerequisites, and clearing any predicates that the Action
/// sets.
void WorldState::applyReverse(const Action &ac, const objects ¶ms)
{
operations::const_iterator o;
Operation op;
Fact f;
for(o = ac.begin(); o != ac.end(); o++)
{
op = o->second;
f = o->first;
if(params.size())
{
fillOp(op, params);
fillFact(f, params);
}
// If there's no condition, check the effects.
if(op.ctype == NoCondition)
{
switch(op.etype)
{
case Set:
//_set(f,op.eval);
_unset(f);
break;
case Unset:
_set(f,op.eval);
break;
case Increment:
_set(f, op.eval - 1);
break;
case Decrement:
_set(f, op.eval + 1);
break;
}
}
else
{
switch(op.ctype)
{
case IsSet:
_set(f, 0);
break;
case Equals:
_set(f, op.cval);
break;
case IsUnset:
_unset(f);
break;
}
}
}
updateHash();
}
void SimpleWorldState::unset(Predicates::predID pred, const paramlist ¶ms)
{
if(pred < mState.size())
{
_unset(pred, params);
updateHash();
}
}
void WorldState::unset(const Fact &fact)
{
_unset(fact);
updateHash();
}
