public override ICollection<IParseTree> Evaluate(IParseTree t)
{
// return all children of t that match nodeName
IList<IParseTree> nodes = new List<IParseTree>();
foreach (ITree c in Trees.GetChildren(t))
{
if (c is ITerminalNode)
{
ITerminalNode tnode = (ITerminalNode)c;
if ((tnode.Symbol.Type == tokenType && !invert) || (tnode.Symbol.Type != tokenType && invert))
{
nodes.Add(tnode);
}
}
}
return nodes;
}