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Question

If I have

var currentState: TransformState = .Default
enum TransformState {
    case Default
    case Error(ErrorState)

    enum ErrorState {
        case Custom
        case Default
    }
}

var state = TransformState.Error(.Custom)

How can I check if state == currentState?

Override `==` for your enum. Possible duplicate of [How to test equality of Swift enums with associated values](http://stackoverflow.com/questions/24339807/how-to-test-equality-of-swift-enums-with-associated-values) — JAL, Aug 02 '16 at 22:14
@JAL I saw that question and I was still confused because in my case it is nested enums. — natecraft1, Aug 02 '16 at 22:19

NiñoScript · Accepted Answer · 2016-08-02T22:25:35.740

You just need to implement Equatable for TransformState

TransformState.ErrorState gets it for free, so you can use that fact in your implementations:

extension TransformState: Equatable {}
func ==(lhs: TransformState, rhs: TransformState) -> Bool {
    switch (lhs, rhs) {
    case (.Default, .Default):
        return true

    case let (.Error(lhsErrorState), .Error(rhsErrorState)):
        return lhsErrorState == rhsErrorState

    default:
        return false
    }
}

Note that in Swift 3.0, you'll be able to put the operator overload inside the extension's body.

score 1 · Answer 2 · edited May 23 '17 at 12:32

Your issue is very similar to the thread shown by JAL, because your nest enum TransformState. ErrorState is Equatable.

You can write your own == like:

func == (lhs: TransformState, rhs: TransformState) -> Bool {
    switch (lhs, rhs) {
    case (.Default, .Default):
        return true
    case (.Error(let state1), .Error(let state2)):
        return state1 == state2
    default:
        return false
    }
}
var currentState: TransformState = .Default

var state = TransformState.Error(.Custom)

print(state == currentState) //->false

currentState = .Error(.Custom)
print(state == currentState) //->true

score 1 · Answer 3 · answered Aug 02 '16 at 22:22

Override == for your enum.

func ==(lhs: TransformState, rhs: TransformState) -> Bool {
    switch (lhs, rhs) {
    case (.Default, .Default):
        return true

    case (.Error(.Custom), .Error(.Custom)):
        return true

    case (.Error(.Default), .Error(.Default)):
        return true

    default:
        return false
    }
}

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3 Answers3