Programming By Intention

Everything old is new again. The folks who brought us the eXtreme Programming books were, among other things, promoting a set of best practices in software development. One of them, which they termed “Programming by Intention”, was not actually new, but was something that had been a very common coding technique in languages like COBOL and Smalltalk (usually called “top down” programming) years before. That’s actually a good thing; time-tested practices are often the most credible ones, because they’ve proven their value over and over again under realistic circumstances. In this chapter we’ll examine this practice, first by simply demonstrating it, and then by investigating the advantages we gain by following it. Finally, we’ll discuss it as it relates to testing and testability, and design.