swift-snippet-11.swift

extension RawRepresentable where RawValue == Int {
	
	static var itemsCount: Int {
		var index = 0
		while Self(rawValue: index) != nil { index += 1 }
		return index
	}
	
	static var items: [Self] {
		var items: [Self] = []
		var index = 0
		while let item = Self(rawValue: index) {
			items.append(item)
			index += 1
		}
		return items
	}
}

You could also do this for everything that's Hashable.
See https://github.com/evermeer/Stuff/blob/master/Source/Enum/Enum.swift#L54
And for an explanation: https://github.com/evermeer/Stuff#enum