Logging a Swift enum using NSLog

swift nslog
zoul picture zoul · Jun 5, 2014 · Viewed 16.2k times · Source

I’m trying to log an enum:

enum CKAccountStatus : Int {
    case CouldNotDetermine
    case Available
    case Restricted
    case NoAccount
}

NSLog("%i", CKAccountStatus.Available)

The compiler complains:

Type 'CKAccountStatus' does not conform to protocol 'CVarArg'

Why? I have tried to cast the value:

NSLog("%i", CKAccountStatus.Available as Int)

But that doesn’t fly either:

Cannot convert the expression's type '()' to type 'String'

Answer

rickster picture rickster · Jun 5, 2014

Get the enum's underlying Int value:CKAccountStatus.Available.rawValue.

Enums are not strictly integers in Swift, but if they're declared with an underlying type you can get it with rawValue — whatever that underlying type is. (enum Foo: String will give you strings for the rawValue, etc.) If an enum doesn't have an underlying type, rawValue has nothing to give you. In APIs imported from ObjC, any enum defined with NS_ENUM has an underlying integer type (typically Int).

If you'd like to print any enum more descriptively, you might consider making an extension on the enum type that adopts the Printable protocol.

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