How can I compare two enum instances with NO raw type?

Question

Given:

enum Example { case Step1 case Step2(data: String)  }

and:

let a: Example = .Step1
let b: Example = .Step2(data: "hi")

how do I make this work?

print(a == b) // ERROR: Binary operator '==' cannot be applied to two 'Example' operands

Note that I can't give up the custom enum (it cannot contain raw values)

http://stackoverflow.com/questions/31548855/how-to-compare-enum-with-associated-values-by-ignoring-its-associated-value-in-s might also be useful. — rmaddy, Apr 26 '17 at 05:00

score 1 · Accepted Answer · answered Apr 26 '17 at 05:09

1

Implement the Equatable protocol for your enum.

enum Example: Equatable {
    case Step1
    case Step2(data: String)

    static func == (lhs: Example, rhs: Example) -> Bool {
        switch(lhs) {
        case Step1:
            switch(rhs) {
            case Step1:
                return true
            default:
                return false
            }
        case Step2(data: leftString):
            switch(rhs) {
            case Step2(data: rightString):
                return leftString == rightString
            default:
                return false
            }
        }
    }       
}

answered Apr 26 '17 at 05:09

Pedro Castilho

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Is this the only solution? It seems very ugly if you have more of 2 cases! – Martin Jul 04 '17 at 15:34
You can just use `default`, so it scales with the number of cases instead of the square of the number of cases. – Pedro Castilho Jul 04 '17 at 16:32
Yep, I got it. It's a little lack in swift IMHO – Martin Jul 05 '17 at 08:15

How can I compare two enum instances with NO raw type?

1 Answers1