1

I was curious about whether I should avoid using @objc in my swift methods. What benefits would that provide?

2

According to Xcode swift3 -> swift4 migrator, not using @objc everywhere will result in a reduced binary size

https://help.apple.com/xcode/mac/current/#/deve838b19a1

3

What cukr said, but also:

  • @objc is only supported on Apple platforms. If you’re writing general code that might end up running on other platforms some day, you’ll want to avoid it.

  • @objc prevents you from using many of Swift’s nicer features. Like enums with associated values:

      enum State {
      case initialised
      case open(Connection)
      case closed
  }

  @objc func stop(state: State)
             ^ Method cannot be marked @objc because the type of the parameter cannot be represented in Objective-C

    And generics:

      @objc func sum<C>(collection: C) where C: Collection, C.Element == Int
             ^ Method cannot be marked @objc because it has generic parameters

    .

IMO you should only use @objc if you absolutely need it for interacting with Apple frameworks, tools, and techniques.

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Quinn “The Eskimo!” @ DTS @ Apple

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