An experiment construction to treat n-tuples generically.

GenericTuple.scala

trait GenericTuple[T] {

  type Base = T
  type  Left[A]
  type Right[A]

  def <<[A](o:Base, a:A): Left[A]
  def >>[A](a:A, o:Base):Right[A]

}

object GenericTuple {

  implicit def tuple2[A,B] = new GenericTuple[(A,B)] {

    def <<[A](o:Base, a:A) = (o._1, o._2, a)
    def >>[A](a:A, o:Base) = (a, o._1, o._2)

    override type  Left[X] = (A,B,X)
    override type Right[X] = (X,A,B)

  }

  implicit def tuple3[A,B,C] = new GenericTuple[(A,B,C)] {

    def <<[A](o:Base, a:A) = (o._1, o._2, o._3, a)
    def >>[A](a:A, o:Base) = (a, o._1, o._2, o._3)

    override type  Left[X] = (A,B,C,X)
    override type Right[X] = (X,A,B,C)

  }
}

implicit class TupleOps[T](tuple:T) {
  def <<[A](a:A)(implicit ev:GenericTuple[T]) = ev.<<(tuple, a)
}

import GenericTuple._

println( (("nico", "nico") << 2525 << "hoge")._4 )