Do you care about your code? QCon promotes software craftsmanship

I'm at the QCon conference in London, one that I particularly value for its vendor-neutrality and strong content. Yesterday we heard from Robert Martin, founder of Object Mentor, on the subject of software craftmanship, or how to avoid bad code. One of Martin's points is that having code that works is not enough. He makes an analogy with a machine. It's not enough that your car works; when you open the bonnet you want to see good engineering, not a tangle of pipes, wires and belts that somehow hangs together.

Software is vulnerable to poor craftsmanship because code is often well hidden from customers and end-users. Still, the programmer knows whether they are putting together something that just about works, or crafting something excellent that will be understandable and maintainable long into the future.

Martin's talk turned out to be a practical one. There was nothing really new; but plenty to think about. Here are a few of his tips:

• Keep functions and methods short. How short? His principle is to use extract method refactoring until there is nothing more to extract. I got the feeling that he would consider anything over 20 lines suspect.
• Have functions with only a few arguments - preferably no more than two - and don't use boolean arguments because they cause confusion.
• Similarly, a class should be a small batch of code, with only a few variables, a couple of dozen methods.
• Eliminate duplication in your code; use abstraction.
• Give public methods short names, but use long descriptive names for private methods. The code is the documentation.
• Improve code slightly every time you touch it. Sometimes the opposite happens; code decays as fixes get added. If you improve it instead, your project improves over time.
• You need comprehensive tests, otherwise you do not dare to make changes in case something breaks. Test code should be of the same quality as production code; if your tests are slow and buggy, you will not use them or trust them.
• Have short iterations. A month may be too long. Two weeks is good. One week, he suggests, may be ideal; or even less in some cases.

You may not agree with all of these; but I like the underlying objective, which is to code to a high standard rather than just fixing bugs until it runs.

Agree? You can sign the Manifesto for Software Craftsmanship.