infix operator <|: infixr0
infix operator |>: infixl1

precedencegroup infixr0 {
  associativity: right
}
precedencegroup infixl1 {
  associativity: left
  higherThan: infixr0
}

func <| <A, B> (f: (A) throws -> B, a: A) rethrows -> B {
  return try f(a)
}
func |> <A, B> (a: A, f: (A) -> B) -> B {
  return try f(a)
}

struct Box<A> {
  let unbox: A
}
func suchThat<A>(_ x: Box<A>) -> (@escaping (A) -> A) -> Box<A> {
  return { f in Box(unbox: f(x.unbox)) }
}

Box(unbox: 1) |> suchThat <| { $0 + 1 }