function1_closed.scala

implicit val Function1ClosedCartesianCat: ClosedCartesianCat[Function1] = new ClosedCartesianCat[Function1] {
  def id[A]: A => A = identity
  def ○[A, B, C]: (B => C) => (A => B) => (A => C) = f => g => f compose g

  def ⨂[A, C, D]: (A => C) => (A => D) => (A => (C, D)) = f => g => (a => (f(a), g(a)))
  def exl[A, B]: ((A, B)) => A = _._1
  def exr[A, B]: ((A, B)) => B = _._2

  def it[A]: A => Unit = _ => ()

  def ap[A, B]: ((A => B, A)) => B = f => f._1(f._2)
  def curry[A, B, C]: (((A, B)) => C) => (A => (B => C)) = f => a => (b => f((a, b)))
  def uncurry[A, B, C]: (A => (B => C)) => (((A, B)) => C) = f => { case (a, b) => f(a)(b) }
}