Scala.NotImplementedError: an implementation is missing?
I had the same problem because I did not quit the Scala console (in IntelliJ) from sbt with the command:
scala> :q
and then restarted the the console from sbt, so that everything could be compiled again.
> console
It`s not necessary to restart sbt, though.
open example.Lists, you will see below lines:
def sum(xs: List[Int]): Int = ???
def max(xs: List[Int]): Int = ???
use 0
instead of ???
.
Also, putting the correct recursive implementation for the max that should work
def max(xs: List[Int]): Int = {
if(xs.isEmpty){
throw new java.util.NoSuchElementException()
}
val tailMax = if (xs.tail.isEmpty) xs.head else max(xs.tail)
if (xs.head >= tailMax){
xs.head
}
else tailMax;
}
I have suffered the same problem. But I have fixed it.
The solution is that you should restart your "sbt console", and import the module again, it works fine.