Swift Dictionary Literal Convertible

dictionary-literal-convertible.swift

import Foundation

/// Timeout Options
struct Options {
  let timeout: Double = 1 // timeout in seconds
  let message = "Timeout failed."    // message to display on timeout
}

/// Wait for something with timeout options
func wait(options: Options) {
  println("Waiting for \(options.timeout). Message: \(options.message)")
  // TODO: wait for some condition
}

enum OptionKey {
  case Timeout, Message
}

extension Options: DictionaryLiteralConvertible {
  typealias Key = OptionKey
  typealias Value = AnyObject

  init(dictionaryLiteral elements: (Key, Value)...) {
    for (key, value) in elements {
      switch key {
        case .Timeout: timeout = value as Double
        case .Message: message = value as String
      }
    }
  }
}

wait(Options(timeout: 0.1, message: "Custom timeout failed."))

wait([.Timeout: 0.1])
wait([.Timeout: 0.1, .Message: "Custom timeout failed."])