Demo of SingletonProductArgs from shapeless-2.2.0

gistfile1.scala

scala> :paste
// Entering paste mode (ctrl-D to finish)

import shapeless._, ops.hlist._, ops.record._

object selectAll extends SingletonProductArgs {
  class Apply[K <: HList] {
    def from[T, R <: HList, S <: HList, Out](t: T)
      (implicit
        gen: LabelledGeneric.Aux[T, R],
        sel: SelectAll.Aux[R, K, S],
        tp: Tupler.Aux[S, Out]
      ): Out =
      tp(sel(gen.to(t)))
  }

  def applyProduct[K <: HList](keys: K) = new Apply[K]
}

case class Quux(i: Int, s: String, b: Boolean, d: Double)

// Exiting paste mode, now interpreting.

import shapeless._
import ops.hlist._
import ops.record._
defined object selectAll
defined class Quux

scala> val quux = Quux(23, "foo", true, 2.0)
quux: Quux = Quux(23,foo,true,2.0)

scala> selectAll('i, 's).from(quux)
res0: (Int, String) = (23,foo)

scala> selectAll('d, 'b, 'i).from(quux)
res1: (Double, Boolean, Int) = (2.0,true,23)