Type classes in scala

gistfile1.scala

  trait TypeClass1[T]{
    def add(a:T,  b:T) : T
  }

  implicit val ints = new TypeClass1[Int]{
    def add(a: Int, b: Int) = a+b
  }

  def sum[T: TypeClass1](list: List[T]) = {
    require(!list.isEmpty)
    val typeClass = implicitly[TypeClass1[T]]
    list.reduce(typeClass.add(_,_))
  }