Program construction consists of a sequence of refinement steps.
Many people tend to look at programming styles and languages like religions: if you belong to one, you cannot belong to others. But this analogy is another fallacy.
Software development is technical activity conducted by human beings.
Yet, I am convinced that there is a need for high quality software, and the time will come when it will be recognized that it is worth investing effort in its development and in using a careful, structured approach based on safe, structured languages.
Usually its users discover sooner or later that their program does not deliver all the desired results, or worse, that the results requested were not the ones really needed.
The possible solutions to a given problem emerge as the leaves of a tree, each node representing a point of deliberation and decision.
The idea that one might derive satisfaction from his or her successful work, because that work is ingenious, beautiful, or just pleasing, has become ridiculed.
Programming is usually taught by examples.
Our ultimate goal is extensible programming (EP). By this, we mean the construction of hierarchies of modules, each module adding new functionality to the system.
Nevertheless, I consider OOP as an aspect of programming in the large; that is, as an aspect that logically follows programming in the small and requires sound knowledge of procedural programming.
My being a teacher had a decisive influence on making language and systems as simple as possible so that in my teaching, I could concentrate on the essential issues of programming rather than on details of language and notation.
It is evidently necessary to generate and test candidates for solutions in some systematic manner.
Indeed, the woes of Software Engineering are not due to lack of tools, or proper management, but largely due to lack of sufficient technical competence.
In the practical world of computing, it is rather uncommon that a program, once it performs correctly and satisfactorily, remains unchanged forever.
I have never designed a language for its own sake.
Experience shows that the success of a programming course critically depends on the choice of these examples.
Clearly, programming courses should teach methods of design and construction, and the selected examples should be such that a gradual development can be nicely demonstrated.
But quality of work can be expected only through personal satisfaction, dedication and enjoyment. In our profession, precision and perfection are not a dispensible luxury, but a simple necessity.
But active programming consists of the design of new programs, rather than contemplation of old programs.
A good designer must rely on experience, on precise, logic thinking; and on pedantic exactness. No magic will do.
My duty as a teacher is to train, educate future programmers.