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  1. class Test(var x: Float, var y: Float) {
  2. 	@inline final def :=(x: Float, y: Float) = {
  3. 		this.x = x
  4. 		this.y = y
  5. 	}
  6. 	@inline final def :=(o: Test) = { //reassign from arg "o"
  7. 		x = o.x
  8. 		y = o.y
  9. 	}
  10. 	@inline final def :=(of: (Test) => Unit) = { //apply mutating function "of"
  11. 		of(this)
  12. 	}
  13. 	@inline final def something_m = { //just an example of mutating function that does something
  14. 		x = 42
  15. 	}
  16. 	override def toString() = x.toString() + ", " + y.toString()
  17. }
  18.  
  19. object Benchmark {
  20. 	@inline final def benchmark(name: String, fun: () => Any) = {
  21. 		val t1 = System.currentTimeMillis()
  22. 		val res = fun()
  23. 		val t2 = System.currentTimeMillis()
  24. 		name + ": " + (t2 - t1).toFloat / 1000 + "sec; Result:" + res.toString()
  25. 	}
  26. 	val tmp = new Test(0, 0)
  27. 	@inline final def calc_something_for_reassign(a: Float, b: Float) = { //Assigns result to temporary object and exposes it (it's also dangerous)
  28. 		tmp := (a, b)
  29. 		tmp.something_m
  30. 		tmp
  31. 	}
  32. 	@inline final def calc_something_for_forwarding(a: Float, b: Float) = { //Creates a function that modifies its argument to the result
  33. 		(result: Test) =>
  34. 			{
  35. 				result := (a, b)
  36. 				result.something_m
  37. 			}
  38. 	}
  39.  
  40. 	@inline final def run_a(spins: Int) = {
  41. 		val x = 2f
  42. 		val y = 3f
  43. 		benchmark("reassignment", () => {
  44. 			val v = new Test(x, y)
  45. 			var i = spins
  46. 			while (i > 0) {
  47. 				i -= 1
  48. 				v := calc_something_for_reassign(v.x, v.y) //Calculates temporary value and assigns it to `v`
  49. 			}
  50. 			v
  51. 		})
  52. 	}
  53.  
  54. 	@inline final def run_b(spins: Int) = {
  55. 		val x = 2f
  56. 		val y = 3f
  57. 		benchmark("forwarding", () => {
  58. 			val v = new Test(x, y)
  59. 			var i = spins
  60. 			while (i > 0) {
  61. 				i -= 1
  62. 				v := calc_something_for_forwarding(v.x, v.y) //Forwards `v` to mutating function created in right-hand side
  63. 			}
  64. 			v
  65. 		})
  66. 	}
  67. }
  68.  
  69. object Main {
  70. 	def main(args: Array[String]) {
  71. 		println(Benchmark.run_a(Int.MaxValue/100))
  72. 		println(Benchmark.run_b(Int.MaxValue/100))
  73. 		println(Benchmark.run_b(Int.MaxValue/100))
  74. 		println(Benchmark.run_a(Int.MaxValue/100))
  75. 	}
  76. }
Success #stdin #stdout 0.95s 247424KB
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reassignment: 0.091sec; Result:42.0, 3.0
forwarding: 0.272sec; Result:42.0, 3.0
forwarding: 0.241sec; Result:42.0, 3.0
reassignment: 0.092sec; Result:42.0, 3.0
https://ideone.com/A62Ts
language:
Scala (scala 2.12.8)
created:
11 years ago
visibility:
public

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