Cool software design insight #1

I plan to progressively discuss a few things I have learned about software design during the rest of the year. Trivial things that make a big difference in your productivity. I do not claim that any of these insights will be novel in any way.

As a college professor, I do not code full time. Usually, I build dirty software that will last just long enough to make a point. I do not need to build industrial-strength software. I have no business needs to satisfy. I can afford to throw away code and never look at it again once a research project is completed. None of my code needs to run for more than a few days at a time.

With this disclosure in place, here is insight #1:

Remove features as often as you can.

Repeatedly, I have observed that my software is too complex for its own good as months go by. Often, I thought that my code would need to do X when, in reality, the need never arises. For example, maybe you wrote code that could sort strings or integers, and you realize that you never sort integers.

It is tempting to leave these extra functions in place. After all, what is the harm? And maybe I will need the extra power some day.

However, I have learned that I systematically underestimate the cognitive overhead of these useless features. I always think that this little extra template parameter is harmless. It is only after removing it, and working with my code some more that I realize how much easier my work has become.

So, drop useless flags and parameters. Do your brain a favor!

Daniel Lemire, "Cool software design insight #1," in Daniel Lemire's blog, July 30, 2008.

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Daniel Lemire

A computer science professor at the University of Quebec (TELUQ).

2 thoughts on “Cool software design insight #1”

  1. I also came to the same conclusion after working as a commercial programmer for a few years. When it comes to code “less is more”.

    While it’s not a solution for everything, one thing test driven design does well is make you focus on the features that are essential. The best way to avoid useless features is not write them in the first place!

    Instead, you write simple tests that exercises only the functionality you want and the game is then to implement enough code to get the tests passing and then stop. If you need more features, write new tests and repeat.

    Not only do you avoid unnecessary, over-general code but writing the tests means when you do need to refactor to add new features you can easily check whether the old functionality is still working.

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