Power.scala

case class Power(first: Component, second: Component) extends Component {
  override def toTree(implicit c: blackbox.Context): c.Tree = {
    import c.universe._
    q"Math.pow(${first.toTree}, ${second.toTree})"
  }
  override def derive: Component = this match {
    case Power(Variable(_), DoubleConstant(b)) =>
      Multiply(second, Power(first, DoubleConstant(b - 1)))
  }
}