Amhansh

Abstraction

This is our key intellectual tool—the ability to separate the essential from the auxiliary, to see the idea that presides over the realization and that it might initially hide.

Distinction between specification

Getting this distinction right is a constant theme in software discussions: “This is only an implementation detail!” “No, it’s really part of what we want to do.” “No, it’s only one way of doing it!” “Show me another!” “It doesn’t matter that I don’t see another way at the moment; someone could come up with one later.” This problem is unique to software because we deal with virtual, ethereal quantities. No one would confuse a bridge with the drawing of the bridge or a car with the plan of the car. You will not fall off the drawing into the water, and you cannot get run over by the plan. But in software, the distinction is often far from clear; unlike in Magritte’s painting, we constantly risk confusing the pipe and the picture of the pipe. Learning to focus on the real issue is part of becoming a software professional.

Recursion

The issue is not just recursive routines—a technique— but the general mode of reasoning that defines a concept by applying the definition itself to some of its parts. It is dizzying at first, but once you have learned to use recursion properly, you have gained a powerful intellectual tool, applicable throughout the field.

Information hiding

Deciding what you export to the rest of the world and what you keep to yourself is a skill that software developers learn only through a combination of good examples and practice.