Using shapeless to drive Ammonite's PPrinter derivation, used to print shapeless values

ammonite-shapeless

> runMain ammonite.repl.Repl
[info] Running ammonite.repl.Repl
Loading Ammonite Repl...

@ load.ivy("com.chuusai" %% "shapeless" % "2.1.0")

@ import shapeless._
import shapeless._

@ 1 :: "lol" :: List(1, 2, 3) :: HNil
res2: Int :: String :: List[Int] :: HNil = ::(
  1,
  ::("lol", ::(List(1, 2, 3), HNil))
)

@ import ammonite.pprint._
import ammonite.pprint._

@ implicit val hnilPPrinter: PPrinter[HNil] = PPrinter[HNil] { (hnil, cfg) => Iterator("HNil") }
hnilPPrinter: PPrinter[HNil] = ammonite.pprint.PPrinter$$anon$1@3e8db096

@ implicit def hlistPPrinter[T <: HList, H](implicit
    tailPPrinter: PPrinter[T],
    headPPrint: PPrint[H]
  ): PPrinter[H :: T] = PPrinter { case (h :: t, cfg) =>
      headPPrint.render(h) ++ Iterator(" :: ") ++ tailPPrinter.render(t, cfg)
  }
defined function hlistPPrinter

@ 1 :: "lol" :: List(1, 2, 3) :: HNil
res6: Int :: String :: List[Int] :: HNil = 1 :: "lol" :: List(1, 2, 3) :: HNil