How to make it interoperable with Objective C?

I may be missing something fundamental here, but I'm having a difficult time making this library interoperate well with Objective C

Our API handler is in Swift but the object parser is in Objective C and difficult to refactor into Swift for now.

The API handler looks something like this:

public typealias JSONCodable = [String: AnyCodable]

struct MyObjectsResponse: Codable {
    let myObjects: [JSONCodable]

    enum CodingKeys: String, CodingKey {
        case myObjects
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)

        self.myObjects = try container.decode([JSONCodable].self, forKey: .myObjects)        
    }
}

Now in the objective-c object parser, we have something like this, where data is a single element from the myObjects array from the MyObjectsResponse above, being passed in from swift:

- (instancetype)initWithData:(NSDictionary *)data
{
    self = [super init];
    if (self) {
        self.myItemId = data[@"id"];

        NSString *myEnumString = data[@"my_enum"];
        if ([myEnumString isEqualToString:@"foo"]) {
            self.myEnum = MyEnumFoo;
        }
        if ([myEnumString isEqualToString:@"bar"]) {
            self.myEnum = MyEnumBar;
        }
    }
    return self;
}

This fails with the following exception:

-[__SwiftValue isEqualToString:]: unrecognized selector sent to instance 0x600001965600

In the debugger at the exception breakpoint:

(lldb) po data
{
    id = "AnyCodable(\"abc123\")";
    "my_enum" = "AnyCodable(\"bar\")";
}

How can I get AnyCodable to interoperate seamlessly with Objective C types and methods like NSString and isEqualToString:?

cc @mattt

Flight-School / AnyCodable

How to make it interoperable with Objective C? #50