Iterating through an Enum in Swift 3.0

Question

I have a simple enum that I would like to iterate over. For this purpose, I\'ve adopted Sequence and IteratorProtocol as shown in the code below. BTW, this can be copy/paste

Answer 1

Note that Martin’s solution can be refactored as a protocol:

import Foundation

protocol EnumSequence
{
    associatedtype T: RawRepresentable where T.RawValue == Int
    static func all() -> AnySequence
}
extension EnumSequence
{
    static func all() -> AnySequence {
        return AnySequence { return EnumGenerator() }
    }
}

private struct EnumGenerator: IteratorProtocol where T.RawValue == Int {
    var index = 0
    mutating func next() -> T? {
        guard let item = T(rawValue: index) else {
            return nil
        }
        index += 1
        return item
    }
}

Then, given an enum

enum Fruits: Int {
    case apple, orange, pear
}

you slap the protocol and a typealias:

enum Fruits: Int, EnumSequence {
    typealias T = Fruits
    case apple, orange, pear
}

Fruits.all().forEach({ print($0) }) // apple orange pear