Macros

Macros.scala

import scala.reflect.macros.whitebox.Context
import scala.language.experimental.macros

object Macros {
  def reverse(id: Any): Any = macro reverseImpl
  def reverseImpl(c: Context)(id: c.Expr[Any]) : c.Expr[Any] = {
    import c.universe._
    println(id)
    println(id.tree)
    println(id.getClass)
    println(id.tree.getClass)
    val Ident(TermName(name)) = id.tree
    c.Expr[Any](Ident(TermName(name.reverse)))
  }
}

result.txt

 ~/work
[mizushima]$ scalac Usage.scala
Expr[Nothing](foo)
foo
class scala.reflect.api.Exprs$ExprImpl
class scala.reflect.internal.Trees$Ident

Usage.scala

object Usage {
  def main(args: Array[String]): Unit = {
    val foo = 100
    val oof = 200
    println(Macros.reverse(foo))
  }
}