Expr2.scala

c.Expr {
  Apply(
    Ident(TermName("println")),
    List(
      Apply(
        Select(
          Apply(
            Select(
              Literal(Constant("hello ")),
              TermName("$plus")
            ),
            List(
              s.tree
            )
          ),
          TermName("$plus")
        ),
        List(
          Literal(Constant("!"))
        )
      )
    )
  )
}