/*
* Returns true if the KC_PrologExpression on the unit has already been evaluated, false otherwise.
* Given a unit containing a KC_PrologExpression and a blackboard, returns true if there is a
* L_SelectedUnitLink to a Unit with a KC_EvaluatablePrologExpression matching the KC_PrologExpression.
*/
protected static bool HasLinkToEvaluatedExpression(Unit unit, IBlackboard blackboard)
{
ISet <(IUnit, string, LinkDirection)> links = blackboard.LookupLinks(unit);
foreach ((IUnit linkedIUnit, string type, LinkDirection dir) in links)
{
/*
* There should only be up to 1 outgoing L_SelectedUnit link, but since I'm not enforcing this on the blackboard,
* for now testing all L_SelectedUnit links until I find a matching KC_EvaluatablePrologExpression
*/
if (type.Equals(LinkTypes.L_SelectedUnit) && dir == LinkDirection.End)
{
Unit linkedUnit = linkedIUnit as Unit;
// If the linkedUnit contains a matching, evaluated, KC_EvaluatablePrologExpression, return true.
if (linkedUnit.HasComponent <KC_EvaluatablePrologExpression>())
{
KC_EvaluatablePrologExpression evaledPrologExp = linkedUnit.GetComponent <KC_EvaluatablePrologExpression>();
if (evaledPrologExp.PrologExpName.Equals(unit.GetPrologExpName <KC_PrologExpression>()) && evaledPrologExp.Evaluated)
{
Debug.Assert(evaledPrologExp.PrologExp.Equals(unit.GetPrologExp()));
return(true);
}
/* fixme
* Consider making this recursively search links if the linked Unit has an EvaluatablePrologExpression with a matching name but it has
* not been evaluated (though currently there's no KS in the system that does this) OR there's a PrologExpression with a matching name.
* The latter is a likely use case. If we downselected in a pool with prolog expressions first, then evaluated those, that would result
* in this case.
*/
}
}
}
return(false); // No linked, matching KC_EvaluatablePrologExpression was found.
}
public static Unit FindOriginalUnit(Unit unit, IBlackboard blackboard)
{
var linkToPreviousUnitsInFilterChain = from link in blackboard.LookupLinks(unit)
where link.LinkType.Equals(LinkTypes.L_SelectedUnit)
where link.Direction.Equals(LinkDirection.Start)
select link;
int count = linkToPreviousUnitsInFilterChain.Count();
// There should be 0 (if we've reached the original) or 1 (if we're still crawling back up the filter chain) links.
Debug.Assert(count == 0 || count == 1);
if (count == 0)
{
return(unit); // The passed in CU was the parent of a chain.
}
else
{
// Recursively search back up the filter chain
(IUnit previousUnitInChain, _, _) = linkToPreviousUnitsInFilterChain.ElementAt(0);
return(FindOriginalUnit((Unit)previousUnitInChain, blackboard));
}
}