CODEWITHSUNDEEP
swift2
r0yalty
r0yalty

Reputation: 63

Conform to protocol?

Using Swift 2.0 I have a problem conforming to a protocol. I broke down the code as much as possible to illustrate the issue.

protocol Filter {
    var filterName:BaseModel {get}
}

protocol BaseModel {
    var name: String {get}
}

enum SomeModel: BaseModel {
    case Something
    var name: String {
        switch self {
        case .Something:
            return "yeah"
        }
    }
}

struct SomeFilter:Filter {

    var filterName:SomeModel
}

With this code I get:

Type 'SomeFilter' does not conform to protocol 'Filter'

Since SomeModel is of type BaseModel (conforms to BaseModel) this should work. If I change change var filterName:SomeModel to var filterName:BaseModel in SomeFilter it works of course, but I can't figure out why it does not see SomeModel as a BaseModel.

Upvotes: 1

Views: 73

Answers (2)

r0yalty
r0yalty

Reputation: 63

So basically I realised I didn't need to create custom filters, just custom Models and ended up with something like this.

protocol Model {
    var name:String {get}
}

struct Filter {
    var model:Model
}


enum SpecificModel: String, Model {
    case Something, SomethingElse

    var name: String {
        switch self {
        case .Something:
            return "something"
        default:
            return rawValue
        }
    }
}

Upvotes: 0

DevAndArtist
DevAndArtist

Reputation: 5159

It's because var filterName: SomeModel is not what the protocol is saying.

You might try something like this with generics to accomplish your idea.

protocol Filter {

    typealias BaseModelType
    var filterName: BaseModelType { get }
}

protocol BaseModel {

    var name: String { get }
}

enum Model: BaseModel {

    case A
    case B

    var name: String {

        switch self {
        case .A:
            return "hello world"
        case .B:
            return "bye world"
        }
    }
}

struct SomeFilter<T: BaseModel>: Filter {

    typealias BaseModelType = T
    var filterName: BaseModelType

    init(filterName: BaseModelType) {

        self.filterName = filterName
    }
}

let test = SomeFilter(filterName: Model.A)

test.filterName.name // prints "hello world"

I hope this might help you somehow. Any feedback is welcome.

Upvotes: 1

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