Question

In Haskell, when I need a quick worker function or helper value, I usually use prime (') that is widely used in mathematics. For instance, if I were to write a reverse function and needed a tail-recursive worker, I would name it reverse'.

In Scala, function names can’t contain a '. Is there any commonly accepted naming scheme for helper functions and values in Scala?

Answer 1

Why don’t you declare the method inside of the method that uses it? Then you can just call it “helper” or whatever you like without having to worry about name conflicts.

scala> def reverse[A](l:List[A]) = {
     |   def helper(acc:List[A],rest:List[A]):List[A] = rest match {
     |     case Nil => acc
     |     case x::xs => helper(x::acc, xs)
     |   }
     |   helper(Nil, l)
     | }
reverse: [A](l: List[A])List[A]

scala> reverse(1::2::3::Nil)
res0: List[Int] = List(3, 2, 1)