Generic failable enum initialization with optional raw value in Swift 2.0

gistfile1.swift

extension RawRepresentable {

  init?(rawValue optionalRawValue: RawValue?) {

    guard let rawValue = optionalRawValue, value = Self(rawValue: rawValue) else { return nil }

    self = value
  }
}

enum Position: Int { case First = 1, Second = 2 }

Position(rawValue: 0) // nil
Position(rawValue: 1) // .First
Position(rawValue: nil) // nil

Thanks! This helped tremendously!

However, Swift 3.0 requires each parameter in the guard statement to be declared with let:

guard let rawValue = optionalRawValue, let value = Self(rawValue: rawValue) else { return nil }