Many years ago, I took part in the development of a taxi-hailing mobile app that is still widely used today. I don’t know what kind of code they’re running now, but in those early days, the driver assignment code –if I remember it correctly– was similar in spirit to the grossly simplified example that follows. There are five levels of nested if statements in less than 30 lines of code. It doesn’t look so bad, some might say, but it’s not difficult to imagine how complicated this code can become with just a few more checks…
What’s fun is determining which function in that list of functions actually is the one where the bug happens and where. I don’t know about other langauges, but it’s quite inconvenient to debug one-linres since they are tougher to step through. Not hard, but certainly more bothersome.
I’m also not a huge fan of un-named functions so their functionality/conditions aren’t clear from the naming, it’s largely okay here since the conditional list is fairly simple and it uses only AND comparisons. They quickly become mentally troublesome when you have OR mixed in along with the changing booleans depending on which condition in the list you are looking at.
At the end of the day though, unit tests should make sure the right driver is returned for the right conditions. That way, you know it works, and the solution is resistant to refactor mishaps.