protected override void VisitPattern(ReteBuilderContext context, PatternElement element)
{
context.RegisterDeclaration(element.Declaration);
if (element.Source == null)
{
AlphaNode currentNode = BuildTypeNode(element.ValueType, _root);
var betaConditions = new List <ConditionElement>();
foreach (var conditionElement in element.Conditions)
{
if (conditionElement.Declarations.Count() > 1)
{
betaConditions.Add(conditionElement);
continue;
}
var alphaCondition = new AlphaCondition(conditionElement.Expression);
SelectionNode selectionNode = BuildSelectionNode(alphaCondition, currentNode);
currentNode = selectionNode;
}
context.AlphaSource = BuildAlphaMemoryNode(currentNode);
if (betaConditions.Count > 0)
{
var joinNode = BuildJoinNode(context, betaConditions);
context.BetaSource = BuildBetaMemoryNode(context, joinNode);
}
}
else
{
Visit(context, element.Source);
//TODO: Handle a more generic case, when pattern adds its own conditions
}
}
private SelectionNode BuildSelectionNode(AlphaCondition condition, AlphaNode parent)
{
SelectionNode selectionNode = parent.ChildNodes
.OfType <SelectionNode>().FirstOrDefault(sn => sn.Conditions.First().Equals(condition));
if (selectionNode == null)
{
selectionNode = new SelectionNode(condition);
parent.ChildNodes.Add(selectionNode);
}
return(selectionNode);
}
private IAlphaMemoryNode BuildAlphaMemoryNode(AlphaNode parent)
{
AlphaMemoryNode memoryNode = parent.MemoryNode;
if (memoryNode == null)
{
memoryNode = new AlphaMemoryNode();
parent.MemoryNode = memoryNode;
}
return(memoryNode);
}
private TypeNode BuildTypeNode(Type declarationType, AlphaNode parent)
{
TypeNode typeNode = parent.ChildNodes
.Cast <TypeNode>().FirstOrDefault(tn => tn.FilterType == declarationType);
if (typeNode == null)
{
typeNode = new TypeNode(declarationType);
parent.ChildNodes.Add(typeNode);
}
return(typeNode);
}