Rewriting Robotics Software in Swift
Brad Larson (via John Siracusa):
At SonoPlot, we just undertook a full rewrite of our robotic control software from Objective-C to Swift. While at first it might appear crazy to rework a large, stable project in a brand-new language, we did so after carefully examining sources of bugs in our Objective-C application and determining that Swift would prevent a large percentage of them.
[…]
I found myself repeatedly saying to myself or Janie that a particular bug wouldn’t have even compiled under Swift, or would have thrown an immediate exception. When we totaled up bugs like this, we found that ~40% of bugs shipped to customers in the last three years would have been caught immediately by using Swift. The primary classes of these bugs were:
- Silent failures due to nil-messaging
- Improperly handled NSErrors, or other Objective-C error failures
- Bad object typecasts
- Wrong enum lookup tables being used for values
This is a great exercise, and of course I like that Swift makes these types of bugs impossible. On the other hand, although I certainly write my share of bugs, I can’t remember the last time one fell into one of these categories. I haven’t counted, but my guess is that it’s less than 1%.
