Pointwise Semigroup

Pointwise.scala

trait Semigroup[A] {
  def op(a1: A, a2: A): A
}

object Semigroup {
  def PointwiseSemigroup[A, B](implicit S: Semigroup[B]): Semigroup[A => B] =
    new Semigroup[A => B] {
      def op(b1: A => B, b2: A => B) =
        a => S.op(b1(a), b2(a))
    }
}