Ada++: object-oriented programming in Ada-83

Many Ada programmers have used object-oriented analysis (OOA) and object-oriented design (OOD) but have never been able to take full advantage of object technology because they could not implement object-oriented programming (OOP) in Ada-83. This paper describes a mechanism to implement OOP in Ada-83. Ada-83 is well suited for object based designs. Implementing the critical OOP features of inheritance and polymorphism in Ada-83 allows a programmer to move beyond an object-oriented design to an object design that utilizes object-oriented programming. By taking advantage of the strengths of both Ada-83 and OOP, software systems that are reliable, resilient to change, and easy to maintain can be developed. This paper provides details on the mechanism used to implement inheritance and polymorphism in Ada-83. This mechanism was developed for real-time applications that could not use Ada's tasking mechanism or dynamic memory allocation. Ada source code examples are provided to illustrate this OOP technique.