快速处理两种不同的值类型

Question

enum Sections: Int {
  case parent
  case general
}

struct Parent {
  let name: String
}


enum General: Int {
  case manage
  case settings

  func title() -> String {
    switch self {
    case .manage:
        return "Manage"
    case .settings:
        return "Settings"
    }
  }
}


struct DataProvider {

  func data(at index: NSIndexPath) -> ? {

    let section =  Sections(rawValue: index.section)!
    switch section {
    case .parent:
        print("parent \(Parent(name: "Venkat"))")
        return Parent(name: "Venkat")
    case .general:
        let general = General(rawValue: index.row)!
        print(general.title())
        return general
     }
 }
}

Here, func data(at index: NSIndexPath) needs to return value type based on indexpath. I tried with protocol but it need property requirement to handle in cell level. Any other way to implement the method and also "General" enum implementation

Answer 1

You could make a shared parent/protocol, then the function could return a shared parent instance, which you can then conditionally down cast. Or you could have the function return AnyObject which is a shared parent.

func data(atIndex: NSIndexPath) -> AnyObject {/*implementation*/}
/*
* Later in another function
*/
let someObj = data(atIndex:index)
if let parentObj = someObj as? Parent
{
 // Do what you need with the parent object, possibly save it to a parent ref
}

And you can do that similarly for the General type. This is not a super scalable system because if you have 3-4 more types in a function that you want to return it gets messy with checking which type it is.

At that point though you would probably want to redesign your code, the return type of function should be constant whenever possible.