count and allValues on Int-based enums

Enum+CaseCountable.swift

protocol CaseCountable { }

extension CaseCountable where Self : RawRepresentable, Self.RawValue == Int {

    static var count: Int {
        var count = 0
        while let _ = Self(rawValue: count) { count+=1 }
        return count
    }

    static var allValues: [Self] {
        return (0..<count).flatMap({ Self(rawValue: $0) })
    }
}


enum Someenum: Int {
    case one, two, three, four
}

extension Someenum: CaseCountable { }

Someenum.count
Someenum.allValues