Chapter 26. Software Revisited: (I)SAR Clarified

In the last chapter, I said that there are three major parts to any computer program: Structure, Action, and Results.

Now also, a program has Input, which could be considered a fourth part of the program, although usually it's not the programmer who's creating the input, but the user. So we can either abbreviate this as SAR or ISAR, depending on whether or not we want to include "Input."

Now, some people misunderstood me and said, "Oh, SAR is just another name for MVC." No, I used MVC as an example of SAR, but SAR is a much, much broader concept than MVC – they are not comparable theories.

MVC is a pattern for designing software, whereas SAR (or ISAR) is a statement of the three (or four) components that are present in all software.

The fascinating thing about SAR is that it applies not only to a whole program, but also to any piece of that program. A whole program has a Structure, just as a function...