Swift Random Unification Design

Random.swift

public protocol RandomSource {
  static var shared: RandomSource { get }
  func next<T : FixedWidthInteger>(_ type: T.Type) -> T
  func nextUniform<T : BinaryFloatingPoint>(_ type: T.Type) -> T
}

// Utilizes /dev/urandom
public class DevRandom: RandomSource {
  public static let shared = DevRandom()
	
  public func next<T : FixedWidthInteger>(_ type: T.Type) -> T {
  }
	
  public func nextUniform<T : BinaryFloatingPoint>(_ type: T.Type) -> T {
  }
}

public protocol UnsafeRandomSource {
  init<T : Numeric>(seed: T)
}

public class XoroshiroRandom: RandomSource, UnsafeRandomSource {
  public static let shared = XoroshiroRandom(seed: Int.random)
	
  public init<T : Numeric>(seed: T) {
  }
	
  public func next<T : FixedWidthInteger>(_ type: T.Type) -> T {
  }
	
  public func nextUniform<T : BinaryFloatingPoint>(_ type: T.Type) -> T {
  }
}

extension RandomAccessCollection {
  public var random: Element {
    return random(using: DevRandom.shared)
  }
	
  public func random(using source: RandomSource) -> Element {
  }
}

extension Range where Bound : BinaryFloatingPoint {
  public var random: Bound {
    return random(using: DevRandom.shared)
  }
	
  public func random(using source: RandomSource) -> Bound {
  }
}

extension ClosedRange where Bound : BinaryFloatingPoint {
  public var random: Bound {
    return random(using: DevRandom.shared)
  }
	
  public func random(using source: RandomSource) -> Bound {
  }
}

public protocol Randomizable {
  static var random: Self
  static func random(using souce: RandomSource) -> Self
}

extension Randomizable {
  public static var random: Self {
    return random(using: DevRandom.shared)
  }
}

extension FixedWidthInteger: Randomizable {
  public static func random(using source: RandomSource) -> Self {
    return (0 ..< Self.max).random(using: source)
  }
}

extension BinaryFloatingPoint: Randomizable {	
  public static func random(using source: RandomSource) -> Self {
    return (0 ... 1.0).random(using: source)
  }
}

// Save this for a separate proposal, but introduce the link between the two proposals

extension RandomAccessCollection {
  public func shuffled(using source: RandomSource = DevRandom.shared) -> Self {
  }
}

extension MutableCollection {
  public mutating func shuffle(using source: RandomSource = DevRandom.shared) {
  }
}

Usage.swift

print((0 ..< 10).random)
print((0 ..< 1.0).random)
let greetings = ["hi", "hello", "hola", "hey"]
print(greetings.random(using: XoroshiroRandom.shared))

let customXoro = XoroshiroRandom(seed: 16)
print(greetings.random(using: customXoro))
print(customXoro.next(UInt8.self))

print(Int.random) // (0 ..< Int.max).random
print(Double.random(using: customXoro)) // (0 ... 1.0).random(using: customXoro)

// Save this for a separate proposal, but introduce the link between the two proposals
print(greetings.shuffled()) // ["hello", "hey", "hi", "hola"] an example output

var numbers = Array(0 ..< 5)
numbers.shuffle(using: customXoro)
print(numbers) // [1, 4, 2, 0, 3] an example output