Blogger - Scalaz Motivation - 10

trait FoldLeft[M[_]] {
  def foldLeft[A, B](ma: M[A], b: B, op: (B, A) => B): B
}

object FoldLeft {
  implicit object ListFoldLeft extends FoldLeft[List] {
    def foldLeft[A, B](ma: List[A], b: B, op: (B, A) => B) = ma.foldLeft(b)(op)
  }
}