chunkedEnumerable.fs

let chunk n (source : seq<'a>) =
  let makechunk (source : System.Collections.Generic.IEnumerator<'a>) n =
    seq { yield source.Current
          let mutable i = 0
          while (i < n) && source.MoveNext() do
           yield source.Current
           i <- i + 1
    }
  seq { use enumerator = source.GetEnumerator()
        while enumerator.MoveNext() do
          yield makechunk enumerator (n-1)
  };;