Scala, lazy evaluation and the Sieve of Eratosthenes

I found a Scala algorithm for the Sieve of Eratosthenes here

Since that was written, the #:: object has been added to Stream and can be used instead of Stream.cons. Also as of a recent nightly build, #:: now object works in Stream pattern matching which means the Sieve of Eratosthenes can be even closer to the haskell implementation. (Presumably a good thing as it broadens your choices)

object Primes {
 
  /* Haskell...
  primes = sieve [2..]
  sieve (p : xs) = p : sieve [x | x <− xs, x `mod` p > 0]
  */ 
 
  def primes = {
    def sieve(is: Stream[Int]): Stream[Int] = is match { 
      case p #:: xs => p #:: sieve(for (x <- xs if x % p > 0) yield x)
    }
    sieve(Stream from 2)
  }

  def main(args: Array[String]) {
    primes take 100 foreach println
  }
}

Nice!