Why doesn't implicit conversion work here?

124 views Asked by At

Given,

trait GetOrElseAble[Container[_]] {
  def getOrElse[A](one : Container[A], two : A) : A
}

And,

implicit val optionGetOrElseAble = new GetOrElseAble[Option] {
  override def getOrElse[A](one: Option[A], two: A): A = one.getOrElse(two)
}

And,

trait GetOrElseOp[A,F[_]] {
  val evidence : GetOrElseAble[F]
  val value : F[A]
  def |(other : A) : A = evidence.getOrElse(value,other)
}

And finally the implicit def,

implicit def toGetOrElseOp[A,F[_]](f : F[A])(implicit e : GetOrElseAble[F])  = new GetOrElseOp[A,F] {
  override val evidence = e
  override val value = f
}

Following works:

toGetOrElseOp(None)(optionGetOrElseAble) | 100

However, None | 100 does not work.

According to my understanding, the implicit def should have kicked in, converted None to the type GetOrElseOp and the above should have worked.

What am I missing? Thanks!

0

There are 0 answers