Struct containing the displayNames and codes for the common ISO currency codes.

CurrencyDataSource.swift

struct Currency {

    let code, displayName: String
    
    init?(code: String?) {
        if let code = code, 
            displayName = NSLocale.systemLocale().displayNameForKey(NSLocaleCurrencyCode, value:code) {
            self.code = code
            self.displayName = displayName
        } else {
            return nil
        }
    }
    
}

struct CurrencyDataSource {

    let currencies: [Currency] = {
    // The first `map` can be replaced with `flatMap` in Swift 2.0
    // to remove the `filter` and `map` calls afterwards
        NSLocale.commonISOCurrencyCodes().map {
                return Currency(code: $0 as? String)
            }.filter { $0 != nil }.map { $0! }
    }()
    
}