Extending Scala collections

Question

I would like to derive a version of a Scala built-in collection that expands on the functionality for a particular generic type e.g.,

import scala.collection         


        

Answer 1

The reason your example doesn't work is that the return type of the + operation is a HashSet and not a Tuple2Set.

You'll have much more luck using the "pimp my library" pattern instead of inheritance.