Hacker News Reader

Good points, thanks for bringing them up.

Yes, there was some ongoing maintenance of this code where both versions had to be updated. The original author was not a pilot and was unfamiliar with some of the nuances of FAA airspace. One of the reasons they brought me in was that I am a pilot and knew how the FAA's data should be interpreted.

In the end, not a huge deal, but it was annoying when I had to make the same changes in two places.

View on HN

Knowing to DRY there depended on business knowledge that the original author did not have.

While they were wrong in this case, I would say it was a reasonable move to not DRY based on the code pattern itself at the time. And that's the big difference imo - DRYing based strictly on the structure of code vs business processes.

But this implies that you have to guess when and where to DRY, which basically implies that there's no good way but via experience and domain knowledge!

That's not what people want to hear - they want a silver bullet; a set of criteria for which DRY'ing could be determined from the onset!

Reply on news.ycombinator.com