How to display OptionSet values in human-readable form?

Question

Swift has the OptionSet type, which basically adds set operations to C-Style bit flags. Apple is using them pretty extensively in their frameworks. Examples include the options

Answer 1

This is how I did it.

public struct Toppings: OptionSet {
        public let rawValue: Int
        
        public static let cheese = Toppings(rawValue: 1 << 0)
        public static let onion = Toppings(rawValue: 1 << 1)
        public static let lettuce = Toppings(rawValue: 1 << 2)
        public static let pickles = Toppings(rawValue: 1 << 3)
        public static let tomatoes = Toppings(rawValue: 1 << 4)
        
        public init(rawValue: Int) {
            self.rawValue = rawValue
        }
    }
    
    extension Toppings: CustomStringConvertible {
        
        static public var debugDescriptions: [(Self, String)] = [
            (.cheese, "cheese"),
            (.onion, "onion"),
            (.lettuce, "lettuce"),
            (.pickles, "pickles"),
            (.tomatoes, "tomatoes")
        ]
        
        public var description: String {
            let result: [String] = Self.debugDescriptions.filter { contains($0.0) }.map { $0.1 }
            let printable = result.joined(separator: ", ")
            
            return "\(printable)"
        }
    }