Declare Swift struct which becomes enum in Objective-C?

Question

Approximate code I need to write

@objc(OCSomeEnum)
enum SomeEnum: Int {
  case c1
  case c2
  ...
}

extension UnitySSPPlacementType { //available in swift only
  ...
}

I want to use some multiple values from this enum:

@objc(OCSomeClass)
class SomeClass: NSObject {
  @objc
  init(cases: [SomeEnum]) {
    ...
  }
}

Problem

@objc conflicts with [SomeEnum] (it understands SomeEnum only).

Note: there are similar questions but they are all about how to use swift enum one value inside objc (or vice versa). No one answers how to work with multiple values in boths languages simultaneously.

The only clue I found out:

https://developer.apple.com/documentation/uikit/uiview/1622451-animatewithduration?language=objc https://developer.apple.com/documentation/uikit/uiview/1622451-animate

Swift : struct AnimationOptions

Objective-C:

typedef enum UIViewAnimationOptions : NSUInteger {
    ...
} UIViewAnimationOptions;

But how to declare custom Swift struct which becomes enum in Objective-C ?

Solution

According to @MartinR advice:

@objc
convenience init(cases: Array<Int>) {
  let pCases = cases.map { SomeEnum(rawValue: $0)! }
  self.init(cases: pTypes)
}

init(cases: [SomeEnum]) { ... }

Bridging an array of enums from Swift to Objective-C

Answer 1

Enums in Objective-C are values which is different than Swift . To complement this difference, make your enum conform to RawRepresentable . After conformance, SomeEnum.c1 will be of type Int having a value equal to its rawValue .

Here's an Example:

enum SomeEnum: RawRepresentable {
    case c1, c2
    var rawValue: Int {
        switch self {
        case .c1:
            return 1
        case .c2:
            return 2
        }
    }
    init?(rawValue: Int) {
        switch rawValue {
        case 1:
            self = .c1
        case 2:
            self = .c2
        default:
            return nil
        }
    }
}

@objc(OCSomeClass)
class SomeClass: NSObject {
    @objc init(cases: [SomeEnum.RawValue]) {
    }
}

let someProperty = SomeClass(cases: [SomeEnum.c1.rawValue])

Edit:

Updated Class

@objc(OCSomeClass)
class SomeClass: NSObject {
    @objc convenience init(cases: [SomeEnum.RawValue]) {
        self.init(enumCases: cases.map({SomeEnum(rawValue: $0)}))
    }
    init(enumCases: [SomeEnum?]) {
        
    }
}

let someProperty = SomeClass(cases: [SomeEnum.c1.rawValue])