Don’t Start in Reverse

When I park my (manual-shift) car on a slope, pointing downward, I set the parking brake, and I leave it in reverse as an extra safety measure. Of course that means that when I’m ready to start out again, I have to remember to take it out of gear (as well as releasing the brake), otherwise the car just jumps backwards and stalls.

Today I was reading Joel Spolsky’s “tips for reading other people’s source code”. In spite of the title (Reading Code is Like Reading the Talmud), you don’t have to have studied Talmud to get his point.

You also don’t have to conclude that his point is universally applicable.

Yes, when you have to work with undocumented, unclear code from an unavailable 3rd party, you might have to reverse engineer it to figure out how it does what it does. Or even just what it does.

But when you’re writing the code, especially as part of a team, there’s no reason to write it so that someone else will need to reverse engineer it. Design well, and write clearly, so that you and others will be able to understand it easily and modify it quickly.

Then everyone can move forward without delay.

Necessity is the Mother of Learning

I may be an exception, but if there’s one thing I enjoy, it’s buying the right tool for a specific job, when the job needs doing. It gives me an excuse to buy a new toy, as well as the pleasure of having a task go smoothly. Faithful readers may remember my first post here, Choose and Use the Right Tools, where I didn’t, and how that turned out.

Today I got a second chance, when my son decided to move his PC to the other side of his desk. With my wife’s permission, we set out to drill another hole for the computer cables. (My wife designed the desk, which is probably worth a good deal more than the PC.)

This time, when I got home from work, I was already presented with a new special-purpose hole saw. There was a little concern that it cost $20, but I reassured everyone that it was fine—this time we would use the right tool and get the job done nicely.

We got all prepared: cleared the work area, measured and marked the hole center on the bottom of the desk to ensure clearing the frame of the desk, put masking tape on top to prevent chipping, and drilled a starter hole all the way through. Came to putting the hole saw in the drill, though, and … it wouldn’t fit.

My son sped up—started thinking of all sorts of quick ways to attach it to the drill anyway.

I slowed down. I decided I would either become much more knowledgeable about hole saws in 15 minutes, or we would put the whole thing away ’til tomorrow and ask at the store. Well, I learned about what a hole saw and drill look like together, what mandrels are and what arbors look like, and finally settled on the understanding that my drill should definitely accept bits with up to a 1/2″ diameter shank. Pretty technical, huh!

All I can say is that this newfound knowledge gave me the confidence to open the drill chuck a bit larger, and then the hole saw (1 cm metric shank—do the math) did fit. We continued the job, including drilling the hole half of the way from the top, and the other half of the way from the bottom, so that the finishing cut would be in the middle of the desk thickness where it wouldn’t damage either surface. Out popped a plug of wood, just like in the picture.

What, you might wonder, does all this have to do with learning, and software development?

For years I’ve been trying to learn about regular expressions because they seemed so useful. But I never got very far until this week. I had to prepare a demonstration of integrating a source code editor (my current favorite—Source Insight) with some XML-modified output from PC-Lint. Well, it took me more than a hole saw’s 15 minutes, but a lot less than “years”. About an hour-and-a-half and I had—rather suddenly, it seemed—taken control of regular expressions for myself.

What made the difference? I had a specific task to do. I was no longer focused on the learning, but, as with the hole saw, on the necessity of the task at hand. A real task, whose result I had promised to someone else. With that promise, the learning just came by itself.