pjazdzewski1990

case q"-$x" => Negate(getComponent(x))

pjazdzewski1990

case class Negate(value: Component) extends Component {
  override def toTree(implicit c: blackbox.Context): c.Tree = {
    import c.universe._
    q"-${value.toTree}"
  }
  override def derive: Component = Negate(value.derive)
}

pjazdzewski1990

scala> (0.0 to 1000.0 by 0.1).forall(x => df(x) == 2)
res0: Boolean = true

pjazdzewski1990

f'(x) = 1 + 0 + 1

pjazdzewski1990

f(x) = x + 5 + x

pjazdzewski1990

scala> val df = Scalac.derivative(x => x + 5 + x)
df: Double => Double = <function1>

pjazdzewski1990

//in class Variable
override def derive: Component = DoubleConstant(1)

//in class DoubleConstant
override def derive: Component = DoubleConstant(0)

pjazdzewski1990

private def getComponent(tree: Trees#Tree)(implicit c: blackbox.Context): Component = {
  import c.universe._
  tree match {
    case Ident(TermName(x)) => Variable(x)
    case Literal(Constant(a)) => DoubleConstant(a.toString.toDouble)
  }
}

pjazdzewski1990

//in class Variable
override def toTree(implicit c: blackbox.Context): c.Tree = {
   import c.universe._
   Ident(TermName(name))
}

//in class DoubleConstant
override def toTree(implicit c: blackbox.Context): c.Tree = {
   import c.universe._
   Literal(Constant(value))

pjazdzewski1990

case class Variable(name: String) extends Component {
  override def toTree(implicit c: blackbox.Context): c.Tree = ???
  override def derive: Component = ???
}

case class DoubleConstant(value: Double) extends Component {
  override def toTree(implicit c: blackbox.Context): c.Tree = ???
  override def derive: Component = ???
}