AndreasKostler

// Super simple, recursive flatten
// The _ means we have a weakly polymorphic type
// i.e. we don't care about what type _ is (it will, or will not, be resolved later)
// the type signature for flatMap on Seq is Seq[A] => (A => Seq[B]) => Seq[B]
def flatten(s: Seq[_]): Seq[_] = s flatMap {
  case s: Seq[_] => flatten(s) // If s is a Seq, we recursively flatten
  case s => Seq(s) // If s is atomic, we're done; just package up s
}

// degenerate case

AndreasKostler

Keybase proof

I hereby claim:

• I am andreaskostler on github.
• I am kandre1980 (https://keybase.io/kandre1980) on keybase.
• I have a public key ASAXdg4Wt3DUsCSjWq9LXIf6oCNka0lb1LbHvzYhbEyKMAo

To claim this, I am signing this object:

AndreasKostler

package model

import algebra.DeleteDealerErrors.SellIdError
import cats.MonadError
import play.api.libs.json._
import play.api.mvc.PathBindable
import scala.util.Try

final case class SellId(value: String)

AndreasKostler

object UnionTypes {
  private type ¬[A] = A => Nothing
  private type ¬¬[A] = ¬[¬[A]]

  private type ∈[S, T <: Disjunction] = ¬¬[S] <:< ¬[T#D]
  private type ∉[S, T <: Disjunction] = ¬¬[S] <:!< ¬[T#D]

  /** `S` is `T`. */
  type Is[S, T] = ∈[S, OneOf[T]#Or[Nothing]]

AndreasKostler

object Def {
  import shapeless.{ =:!=, HNil, HList, Nat, Poly1, Succ, Witness }
  import shapeless.nat.{ _0 => D0, _1 => D1, _2 => D2, _3 => D3 }
  import shapeless.ops.nat.{ Diff, GT, LTEq, ToInt }
  import shapeless.ops.hlist.{ Mapper, ToTraversable, ZipConst }

  trait Value {
    def toShortString = ???
  }
  object Value {

AndreasKostler

object Def {
  import shapeless.{ =:!=, HNil, HList, Nat, Poly1, Succ, Witness }
  import shapeless.nat.{ _0 => D0, _1 => D1, _2 => D2, _3 => D3 }
  import shapeless.ops.nat.{ Diff, GT, LTEq, ToInt }
  import shapeless.ops.hlist.{ Mapper, ToTraversable, ZipConst }

  trait Value {
    def toShortString = ???
  }
  object Value {

AndreasKostler

object Abc {
  import shapeless.{ =:!=, Nat, Succ }
  import shapeless.nat.{ _0 => D0, _1 => D1, _2 => D2, _3 => D3 }
  import shapeless.ops.nat.{ Diff, GT, LTEq, ToInt }
  import shapeless.ops.hlist._

  trait Value {
    def toShortString = ???
  }
  object Value {

AndreasKostler

import shapeless._

trait Test {
  def ex[InL <: HList, H, T <: HList](in : InL)(implicit isHCons: IsHCons1.Aux[InL, List[H], T])
  val ii: List[Int]::List[Int]::HNil
  ex(ii)
}

trait IsHCons1[L] { type H; type T <: HList}
object IsHCons1 {

AndreasKostler

import shapeless._
import syntax._
import poly._

object LeftFolderOps {

  trait LeftFolder[C <: Coproduct, In, F] extends Serializable {
    def apply(c: C, in: In): In
  }

AndreasKostler

trait LeftFolder[C <: Coproduct, In, F] extends Serializable {
  def apply(c: C, in: In): In
}

object LeftFolder {
  def apply[C <: Coproduct, In, F](implicit folder: LeftFolder[C, In, F]) = folder

  implicit def hdLeftFolder[H, T <: Coproduct, In, F]
  (implicit f: Case2.Aux[F, In, H, In]): LeftFolder[H :+: T, In, F] = new LeftFolder[H :+: T, In, F] {
    def apply(c: H :+: T, in: In): In = c match {