FunWithContains.Swift

extension GeneratorType {
  mutating func any(predicate: Element -> Bool) -> Bool {
    return next().map { el in predicate(el) || any(predicate) } ?? false
  }
  mutating func all(predicate: Element -> Bool) -> Bool {
    return next().map { el in predicate(el) && all(predicate) } ?? true
  }
}

var i = 0
var g = anyGenerator { ++i }

func testIsOverFive(n: Int) -> Bool {
  print(n) // 1, 2, 3, 4, 5, 6
  return n > 5
}

let ans = g.any(testIsOverFive) // true