//the evaluater uses Reverse Polish Notation
public void evaluate(Token token)
{
IEnumerable<string> newLinkSet = null;
if (stack.Count >= 2)
{
if (token.GetType() == typeof(AndToken))
{
newLinkSet = stack.Pop().Intersect(stack.Pop());
}
if (token.GetType() == typeof(OrToken))
{
newLinkSet = stack.Pop().Union(stack.Pop());
}
if (token.GetType() == typeof(AndNotToken))
{
var excluded = stack.Pop();
var included = stack.Pop();
newLinkSet = included.Except(excluded);
}
stack.Push(newLinkSet);
}
}
//the evaluater uses Reverse Polish Notation
public void evaluate(Token token)
{
IEnumerable <string> newLinkSet = null;
if (stack.Count >= 2)
{
if (token.GetType() == typeof(AndToken))
{
newLinkSet = stack.Pop().Intersect(stack.Pop());
}
if (token.GetType() == typeof(OrToken))
{
newLinkSet = stack.Pop().Union(stack.Pop());
}
if (token.GetType() == typeof(AndNotToken))
{
var excluded = stack.Pop();
var included = stack.Pop();
newLinkSet = included.Except(excluded);
}
stack.Push(newLinkSet);
}
}
private void _query()
{
_andTerm();
if (next.GetType() == typeof(AndNotToken))
{
newSimpleTree(new Node(_tokens.getNextToken()), branchesStack.Pop());
next = _tokens.PeekToken();
_query();
}
else
{
return;
}
}