public override void Init(ParsingContext context, ParseTreeNode treeNode)
{
base.Init(context, treeNode);
OpSymbol = treeNode.MappedChildNodes[0].FindTokenAndGetText();
Argument = AddChild("Arg", treeNode.MappedChildNodes[1]);
base.AsString = OpSymbol + "(unary op)";
base.ExpressionType = context.GetUnaryOperatorExpressionType(OpSymbol);
}