Objective-C enums can be string-backed... sort of

While looking at AVAudioSessionErrorCode in Xcode, I noticed something interesting in its definition: typedef CF_ENUM ( AVAudioInteger , AVAudioSessionErrorCode ) { AVAudioSessionErrorCodeNone = 0 , AVAudioSessionErrorCodeMediaServicesFailed = ' msrv ' , // 0x6D737276, 1836282486 AVAudioSessionErrorCodeIsBusy = ' ! act ' , // 0x21616374, 560030580 AVAudioSessionErrorCodeIncompatibleCategory = ' !…