10 years on, what would you change about Swift?

[Damien_Petrilli (Damien)]

@scanon

The most optimized code performs about the same in every language, because people who know how to navigate their way through the language idioms and compiler quirks have optimized it.

It's true up to a point. It's also about how much abstractions and overhead you can bypass when you need more performance.

It also depends on how optimized fundamental types are implemented:

'Standard' vapor website drops 1.5% of requests, even at concurrency of 100!

Node.js's BigInteger.+ beats attaswift.BigInt.+ by about 3x for the specific case that's being exercised here (n = 10,000), which is precisely within expectations for a naive implementation.

Swift code

import BigInt func fibonacci(_ n: Int) -> BigInt { precondition(n > 0) if n == 1 { return 0 } var previous: BigInt = 0 var current: BigInt = 1 for _ in 2 ... n { let next = previous + current previous = current current = next } return current } let counts = …

And you can detect those thanks to benchmarks.

@scanon

It’s the other code where you can see a difference between languages (especially code written by people who are very used to the optimization idioms and compiler quirks of language B, and naively expect the same techniques to apply to language A).

Another explanation could be that most of what you can do to make Swift fast is only known by Apple Engineers and undocumented unlike C++.