/// <summary>
/// AND(Node, ZERO) -> Zero
/// OR(Node, ZERO) -> Node
/// NOT(ZERO) -> ALL
/// </summary>
/// <returns></returns>
private static ExpressionTreeNode HandleZeroNode(ExpressionTreeNode node, ref int count)
{
if (node == null)
{
return(null);
}
if (node.Child1?.Operation == "ZERO" || node.Child2?.Operation == "ZERO")
{
var otherNode = node.Child1.Operation == "ZERO" ? node.Child2 : node.Child1;
if (node.Operation == "AND")
{
node = ExpressionTreeNode.CreateAllNode();
}
else if (node.Operation == "OR")
{
node = otherNode;
}
else if (node.Operation == "NOT")
{
node = ExpressionTreeNode.CreateAllNode();
}
count++;
}
return(node);
}
/// <summary>
/// OR(NOT, NOT) -> ALL - if terms are not equal
/// OR(NOT, NOT) -> NOT(term) - if terms are equal
/// </summary>
/// <param name="node"></param>
private static ExpressionTreeNode TwoNotInOrRule(ExpressionTreeNode node, ref int count)
{
if (node == null)
{
return(null);
}
if (node.Operation == "OR" && node.Child1.Operation == "NOT" && node.Child2.Operation == "NOT")
{
if (node.Child1.Child1.Term == node.Child2.Child1.Term)
{
node = ExpressionTreeNode.CreateNot(node.Child1.Child1);
}
else
{
node = ExpressionTreeNode.CreateAllNode();
}
count++;
}
return(node);
}