Why no i++ in Scala?

Question

I just wonder why there is no i++ to increase a number. As what I know, languages like Ruby or Python doesn\'t support it because they are dynamically typed. So

Answer 1

Of course you can have that in Scala, if you really want:

import scalaz._, Scalaz._

case class IncLens[S,N](lens: Lens[S,N], num: Numeric[N]) { 
  def ++ = lens.mods(num.plus(_, num.one))
}

implicit def incLens[S,N: Numeric](lens: Lens[S,N]) =
  IncLens[S,N](lens, implicitly[Numeric[N]])

val i = Lens.lensu[Int,Int]((x, y) => y, identity)

val imperativeProgram = for {
  _ <- i++;
  _ <- i++;
  x <- i++
} yield x

def runProgram = imperativeProgram exec 0

And here you go:

scala> runProgram
res26: scalaz.Id.Id[Int] = 3

No need to resort to violence against variables.