enum

Value Members

1. object Values

   

   The companion object contains the machinery to automatically derive the values of a sealed trait extended by case objects only.

   The companion object contains the machinery to automatically derive the values of a sealed trait extended by case objects only.

   Basically, the derivation process is the following:

   • we are given a sort of list containing the types of the case objects that extend a sealed trait A ;
   • we inductively traverse this structure using two implicit definitions: one for the empty list case and one for the “cons” case ;
   • we accumulate the traversed case objects in a List ;
   • that’s it: the resulting List contains all the possible values of type A.

   The first step is the hard part of this process and is actually achieved by shapeless (using macros).