jaked

// I was reading through these examples: http://apocalisp.wordpress.com/2010/06/08/type-level-programming-in-scala/
// and I thought it would be nice to more quickly get to something useful, to show the power of the techniques.
object SizedListExample {
  // Type of all Non-negative integers
  sealed trait Nat
  // This is zero.
  sealed trait _0 extends Nat
  // Successor to some non-negative number
  sealed trait Succ[N <: Nat] extends Nat

jaked

import java.util.concurrent.{BlockingQueue, ArrayBlockingQueue, CountDownLatch, Executors, TimeUnit}

/*
  Abstracts away the common pattern of producing items into a queue that are
  consumed concurrently by a pool of workers.
*/
class ConcurrentBlockingQueueConsumer[T](queue: BlockingQueue[T], producer: Iterator[T], concurrencyLevel: Int) {
  lazy val pool      = Executors.newFixedThreadPool(concurrencyLevel)

  def run()(consumer: (T) => Unit) {

jaked

(* defines the Ast.binding for a function of form:
let fun_name ?(opt_arg1) ?(opt_arg2) final_ident = function_body ...
*)
let function_with_label_args _loc ~fun_name ~final_ident ~function_body ~return_type opt_args =
   let opt_args = opt_args @ [ <:patt< $lid:final_ident$ >> ] in
   let rec fn _loc = function (* could lose _loc and use List.fold_right *)
   |hd::tl -> <:expr< function $hd$ -> $fn _loc tl$ >>
   |[] -> <:expr< ( $function_body$ : $return_type$ ) >>
   in
   <:binding< $lid:fun_name$ = $fn _loc opt_args$ >>