List.sum on custom class

Question

I have the following code that represents GF2 field:

trait GF2 {
  def unary_- = this
  def + (that: GF2): GF2
  def * (that: GF2): GF2

  def / (that: GF2)          


        

Answer 1

You need to implement a version of Numeric for your trait in order for it to work. See here for the full definition you'll need to create.

 object InScope{
   implicit object GF2Numeric extends Numeric[GF2]{
     //..your implementation here
   }
 }

The full signature of sum on a List is actually:

 def sum(implicit num: Numeric[A])

Where by the A is the type of the List[A].