296 

   297 

   298 

   299 

   300 // some automatic timing in each evaluation

   301 package wrappers {  

   302 

   303   object wrap { 

   304    

   305     def timed[R](block: => R): R = {

   306       val t0 = System.nanoTime()

   307       val result = block

   308       println("Elapsed time: " + (System.nanoTime - t0) + "ns")

   309       result

   310     }

   311 

   312     def apply[A](a: => A): A = { 

   313       timed(a)

   314     } 

   315   }

   316 }

   317 

   318 $intp.setExecutionWrapper("wrappers.wrap")

   319 

   320 // Iteration

   321 

   322 def fib(n: Int) : Int = 

   323   if (n <= 1) 1 else fib(n - 1) + fib(n - 2)

   324 

   325 fib(10)

   326 

   327 

   328 Iterator.iterate((1,1)){ case (n: Int, m: Int) => (n + m, n) }.drop(9).next

   329 

   330