The “random” choice of swift was quite fortunate since what this really seems to be testing is the ergonomics of the Unicode “character” definition in the standard libraries used, and swift has the best defaults of the languages mentioned haha
> It’s not that other languages don’t have Unicode-correct APIs at all — most do. For instance, NSString has the enumerateSubstrings method that can be used to walk through a string by grapheme clusters. But defaults matter; Swift’s priority is to do the correct thing by default.
> Strings in Swift are very different than their counterparts in almost all other mainstream programming languages. When you’re used to strings effectively being arrays of code units, it’ll take a while to switch your mindset to Swift’s approach of prioritizing Unicode correctness over simplicity.
> Ultimately, we think Swift makes the right choice. Unicode text is much more complicated than what those other languages pretend it is. In the long run, the time savings from avoided bugs you’d otherwise have written will probably outweigh the time it takes to unlearn integer indexing.
> The Swift implementation was indeed written by ChatGPT, and it got it right first time, with just the prompt “Implement leftpad in Swift”. However: Swift is the only language I know where an implementation that does what I wanted it to do is that simple.
Not really. Swift's defaults happens to match best to these particular requirements. Change the task and you will find other languages have the "best" defaults.