public RPNVariable(RPNExpr owner, RPNObjectType objectType) : base(owner, objectType) { }
public RPNOperand(RPNExpr owner, RPNObjectType objectType) : base(owner, objectType) { }
public RPNDataField(RPNExpr owner, RPNObjectType objectType) : base(owner, objectType) { }
public RPNObject(RPNExpr owner, RPNObjectType objectType) { Owner = owner; ObjectType = objectType; }