Randomizable Potential

potential.swift

struct Date : Randomizable, Strideable {
  typealias Stride = Int

  let timestamp: UInt32
  
  static func random<T: RandomNumberGenerator>(using generator: T) -> Date {
    return Date(timestamp: (0 ... UInt32.max).random!)
  }

  func distance(to other: Date) -> Int {
    return Int(other.timestamp) - Int(self.timestamp)
  }

  func advanced(by n: Int) -> Date {
    return Date(timestamp: UInt32(Int(self.timestamp) + n))
  }
}

struct Color : Randomizable, Strideable {
  typealias Stride = Int

  let value: UInt32

  static func random<T: RandomNumberGenerator>(using generator: T) -> Color {
    return Color(value: (0 ... 0xFFFFFF).random!)
  }

  func distance(to other: Color) -> Int {
    return Int(other.value) - Int(self.value)
  }

  func advanced(by n: Int) -> Color {
    return Color(value: UInt32(Int(self.value) + n))
  }
}

extension Array 
  where Element: Randomizable & Strideable, Element.Stride: SignedInteger {
  init(randomElements: Int, in bounds: CountableRange<Element>) {
    self = (0 ..< randomElements).map { _ in bounds.random! }
  }
  init(randomElements: Int, in bounds: CountableClosedRange<Element>) {
    self = (0 ..< randomElements).map { _ in bounds.random! }
  }
}

let dateRange = Date(timestamp: 100) ..< Date(timestamp: 1000)
print([Date](randomElements: 10, in: dateRange))

let colorRange = Color(value: 0x0000FF) ... Color(value: 0xFF0000)
print([Color](randomElements: 10, in: colorRange))