@swift-4.2.4
swift public struct Uniform { var base: RandomNumberGenerator init(base: RandomNumberGenerator) { self.base = base } /// Returns a value from uniform [low, high) distribution. public mutating func next(low: Float, high: Float) -> Float { print("base before; \(base)") let uint32: UInt32 = base.next() print("base after; \(base)") return (high - low) * (Float(bitPattern: uint32 >> 9 | 0x3f80_0000) - 1) + low } } extension RandomNumberGenerator { public var uniform: Uniform { get { return Uniform(base: self) } set { print("before set: \(self)") self = uniform.base as! Self print("set self: \(self) \(uniform.base)") } } } struct DummyRNG: RandomNumberGenerator { static var `default` = DummyRNG.init() var state: UInt32 = 0 mutating func next<T>() -> T where T : FixedWidthInteger, T : UnsignedInteger { state += 123456789 return T(state) } } print(DummyRNG.default.uniform.next(low: 0, high: 1)) print(DummyRNG.default.uniform.next(low: 0, high: 1)) print(DummyRNG.default.uniform.next(low: 0, high: 1))
