CODEWITHSUNDEEP
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Emre Önder
Emre Önder

Reputation: 2537

Get associated type object from enum without switch

I have an enum with associated types. All associated types conform a protocol. I want to reach a variable from that protocol without switching enum. How can I achieve this?

I want to get position object from enum element without switch.

protocol ComponentModelProtocol {
    var position: Int { get } //Describes in which stackview component will be. (0 means left, 1 means right)
    var isTappable: Bool { get } //Adds gesture recognizer to the view If this is true
}

enum ComponentType {
    case onelinetwolabel(content: LabelComponentModel)
    case twolinelabel(content: BoxComponentModel)
    case labelwithimage(content: BoxComponentModel)
    case currencySelector(content: CurrencySelectorModel)
    case seperator(position: Int)
}

struct CurrencySelectorModel: ComponentModelProtocol {
    let position: Int
    let isTappable: Bool
    let currencyArray: [String]
}

struct LabelComponentModel: ComponentModelProtocol {
    let key: String
    let value: String
    let position: Int
    let isTappable: Bool
    let labelType: OneLineTwoLabel.LabelType

    init(key: String, value: String, position: Int, isTappable: Bool, labelType: OneLineTwoLabel.LabelType) {
        self.key = key
        self.value = value
        self.position = position
        self.isTappable = isTappable
        self.labelType = labelType
    }

    init(key: String, value: String, position: Int) {
        self.init(key: key,value: value,position: position, isTappable: false, labelType: .defaultLabel)
    }

    init(key: String, value: String, position: Int,isTappable: Bool) {
        self.init(key: key,value: value,position: position, isTappable: isTappable, labelType: .defaultLabel)
    }

}

//Struct for two line label component
struct BoxComponentModel: ComponentModelProtocol {
    let key: String
    let value: String
    let position: Int
    let isTappable: Bool

    init(key: String, value: String, position: Int,isTappable: Bool) {
        self.key = key
        self.value = value
        self.position = position
        self.isTappable = isTappable
    }

    init(key: String, value: String, position: Int) {
        self.init(key: key,value: value, position: position,isTappable: false)
    }
    }

I know I can do it with adding variable inside enum like below but It adds switch for every element. I'm looking for a more clever way If there is.

enum ComponentType: ComponentModelProtocol {
    var position: Int {
        switch self {
        case .onelinetwolabel(content: let model):
            return model.position
        case .twolinelabel(content: let model):
            return model.position
        case .labelwithimage(content: let model):
            return model.position
        case .currencySelector(content: let model):
            return model.position
        case .seperator(position: let position):
            return position
        }
    }

Upvotes: 1

Views: 201

Answers (1)

flanker
flanker

Reputation: 4210

The other way to access the associated value is by the rather hideous (IMO 🙂) if case let syntax.

I'm not sure it'll make things any easier so I'll not go into depth here, but all the info you'll need on it is on If Case Let syntax

Upvotes: 1

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