public RelOpASTNode(FactorASTNode left, RelOp relationOperator, FactorASTNode right) : base(SyntaxTreeNodeType.RelOp)
 {
     Left             = left;
     Right            = right;
     RelationOperator = relationOperator;
 }
 public AdditionASTNode(FactorASTNode left, FactorASTNode right) : base(SyntaxTreeNodeType.Plus)
 {
     Left  = left;
     Right = right;
 }