по просьбам читателей

а вот ещё перажок

planet's funniest code

src

def validate[F[_], G, H, V <: HList, I <: HList, M <: HList, A <: HList, R]
  (g: G)(v: V)(implicit
  hlG: FnHListerAux[G, A => R],
  zip: ZipApplyAux[V, I, M],
  mapped: MappedAux[A, F, M],
  unH: FnUnHListerAux[I => F[R], H],
  folder: LeftFolderAux[M, F[A => R], applier.type, F[HNil => R]],
  appl: Applicative[F]
) = unH((in: I) => folder(zip(v, in), hlG(g).point[F]).map(_(HNil)))

(скалу выучили, а как программировать, не выучили)

actually, it makes a lot of sense, like here:

val validateFoo = validate(Foo.apply _)(checkA :: checkB :: checkC :: HNil)

good reading on ifs vs matches

Whenever your program hits a branching point and needs to decide which branch to go down, you yourself hit a crossroad and need to decide how to write it. (This is intended to be very meta!) Your choices are conditional branching and pattern matching.

(10x Shachaf Ben-Kiki for pointing out)

экзамен на кафедре ядерной физики Православной Академии