Problems with Pattern matching, implementing SplitAt in scala

Question

I am trying to implement the scala splitAt using pattern matching and this is what I am trying to do:

def split[T](someIndex:Int,someList:List[T]):(List[T],L         


        

Answer 1

You should use `someIndex` and `currentIndex` (constants) in pattern matching.

scala> val a = 1
a: Int = 1

scala> 2 match {
     |   case a => println(a)
     | }
2

scala> 2 match {
     |   case `a` => println("a")
     |   case _ => println("Oops")
     | }
Oops

Chapter 15 of Programming in Scala, First Edition. "Case Classes and Pattern Matching" by Martin Odersky, Lex Spoon, and Bill Venners:

If you need to, you can still use a lowercase name for a pattern constant, using one of two tricks. First, if the constant is a field of some object, you can prefix it with a qualifier. For instance, pi is a variable pattern, but this.pi or obj.pi are constants even though they start with lowercase letters. If that does not work (because pi is a local variable, say), you can alternatively enclose the variable name in back ticks.