3 ms·

"Swift is slowly evolving into a formidable competitor to ... Rust" "Swift uses Automatic Reference Counting (ARC) to manage memory."

• pjmlp 6y ago
  Just like many Rust code bases that are full of Rc<RefCell<>>, which don't get optimised away by the compiler.
  • pornel 6y ago
    Even that poor case in Rust is already better than what Swift can do, because Swift's refcounting has to be atomic. Swift is too dynamic to prove objects don't escape threads, so it can't optimize that cost away. Rust's Rc/Arc can still selectively use borrowing, which guarantees the level of efficiency that in Swift may or may not happen depending on the optimizer. A borrowed Arc can often stay borrowed across many non-inlined method calls, which you're unlikely to get in Swift.
    • k__ 6y ago
      I really have to learn more about Rust.
    • pjmlp 6y ago
      That assuming that the developer hasn't plagued the code with unnecessary clone() in an attempt to make everything finally compile.