applicatives1.swift

extension Optional {
  func apply<U>(f: (T -> U)?) -> U? {
    switch f {
      case .Some(let someF): return self.map(someF)
      case .None: return .None
    }
  }
}

extension Array {
  func apply<U>(fs: [Element -> U]) -> [U] {
    var result = [U]()
      for f in fs {
        for element in self.map(f) {
          result.append(element)
        }
      }
      return result
    }
}