Enumeration and mapping with Scala 2.10

Question

I\'m trying to port my application to Scala 2.10.0-M2. I\'m seeing some nice improvements with better warnings from compiler. But I also got bunch of errors, all related to

Answer 1

It's basically a type mismatch error. You can work around it by first converting is to a list:

scala> Phrase.values.toList.map(p => (p, new Entity(p.toString))).toMap
res15: scala.collection.immutable.Map[Phrase.Value,Entity] = Map(My phrase 1 -> Entity@d0e999, My phrase 2 -> Entity@1987acd)

For more information, see the answers to What's a “diverging implicit expansion” scalac message mean? and What is a diverging implicit expansion error?

Answer 2

As you can see from your error, the ValueSet that holds the enums became a SortedSet at some point. It wants to produce a SortedSet on map, but can't sort on your Entity.

Something like this works with case class Entity:

implicit object orderingOfEntity extends Ordering[Entity] {
  def compare(e1: Entity, e2: Entity) = e1.text compare e2.text
}