Found error on using list in scala - scala

Question

I am using Scala for studying purpose
I wrote this code to sort the elements in list
def isort(xs:List[Int]):List[Int]=
xs match{
case List() => xs
case y::ys => insert(y,isort(ys))
}
def insert(x:Int,xs:List[Int]):List[Int]=
xs match{
case List() => List(x)
case y::ys => if(x<y) x::xs else y :: insert(x,ys)
}
but I am getting the following error:
Constructor can not be instantiated to expected type found Scala.collection.Immutable required List[Int]
in
`y::ys => insert(y,isort(ys))`
and similar error where I use ::
I refer tutorial : https://class.coursera.org/progfun-005/lecture

Answer 1

Try using the paste mode of the REPL. This will allow you to define the two defs in the same context:
scala> :paste
// Entering paste mode (ctrl-D to finish)
def isort(xs:List[Int]):List[Int]=
xs match{
case List() => xs
case y::ys => insert(y,isort(ys))
}
def insert(x:Int,xs:List[Int]):List[Int]=
xs match{
case List() => List(x)
case y::ys => if(x<y) x::xs else y :: insert(x,ys)
}
// Exiting paste mode, now interpreting.
isort: (xs: List[Int])List[Int]
insert: (x: Int, xs: List[Int])List[Int]