Is Scala idiomatic coding style just a cool trap for writing inefficient code?

Question

I sense that the Scala community has a little big obsession with writing \"concise\", \"cool\", \"scala idiomatic\", \"one-liner\" -if possible- code. This

Answer 1

For reference, here's how splitAt is defined in TraversableLike in the Scala standard library,

def splitAt(n: Int): (Repr, Repr) = {
  val l, r = newBuilder
  l.sizeHintBounded(n, this)
  if (n >= 0) r.sizeHint(this, -n)
  var i = 0
  for (x <- this) {
    (if (i < n) l else r) += x
    i += 1
  }
  (l.result, r.result)
}

It's not unlike your example code of what a Java programmer might come up with.

I like Scala because, where performance matters, mutability is a reasonable way to go. The collections library is a great example; especially how it hides this mutability behind a functional interface.

Where performance isn't as important, such as some application code, the higher order functions in Scala's library allow great expressivity and programmer efficiency.

---

Out of curiosity, I picked an arbitrary large file in the Scala compiler (scala.tools.nsc.typechecker.Typers.scala) and counted something like 37 for loops, 11 while loops, 6 concatenations (++), and 1 fold (it happens to be a foldRight).