Here’s a trick question: How do we get people to understand programming?<
Khan Academy recently launched an online environment for learning to program. It offers a set of tutorials based on the JavaScript and Processing languages, and features a “live coding” environment, where the program’s output updates as the programmer types.
Because my work was cited as an inspiration for the Khan system, I felt I should respond with two thoughts about learning:
- Programming is a way of thinking, not a rote skill. Learning about “for” loops is not learning to program, any more than learning about pencils is learning to draw.
- People understand what they can see. If a programmer cannot see what a program is doing, she can’t understand it.
Thus, the goals of a programming system should be:
- to support and encourage powerful ways of thinking
- to enable programmers to see and understand the execution of their programs
A live-coding Processing environment addresses neither of these goals. JavaScript and Processing are poorly-designed languages that support weak ways of thinking, and ignore decades of learning about learning. And live coding, as a standalone feature, is worthless.
Alan Perlis wrote, “To understand a program, you must become both the machine and the program.” This view is a mistake, and it is this widespread and virulent mistake that keeps programming a difficult and obscure art. A person is not a machine, and should not be forced to think like one.
How do we get people to understand programming?
We change programming. We turn it into something that’s understandable by people.