example.scala

package demo

case class Wrapper[A](arr: Array[A])

object Wrapper {
  def literal[A](as: A*): Wrapper[A] = wrapperMacro
}

object Example {

  def array[A](as: A*) = macro arrayMacro[A]

  def arrayMacro[A: c.WeakTypeTag](c: Context)(as: c.Expr[A]*): c.Expr[Array[A]] = {
    import c.mirror._
    import c.universe._
  
    val n = as.length
    val tpe = implicitly[c.WeakTypeTag[A]].tpe
    val valdef = q"val arr = new Array[$tpe]($n)"
    val updates = as.toList.zipWithIndex.map { case (a, i) =>
      q"arr($i) = ${a.tree}"
    }

    c.Expr[Array[A]](Block(valdef :: updates, q"arr"))
  }

  def wrapperMacro[A: c.WeakTypeTag](c: Context)(as: c.Expr[A]*): c.Expr[demo.Wrapper[A]] = {
    import c.mirror._
    import c.universe._
    val arr = arrayMacro(c)(as: _*)
    c.Expr[demo.Wrapper[A]](q"demo.Wrapper($arr)")
  }

}