gistfile1.txt

import language.experimental.macros
import language.implicitConversions
import scala.reflect.macros.Context
import scala.reflect.runtime.universe.Tree

class ReflectiveClosure[A, B](val tree: Tree, fn: Function1[A, B]) extends Function1[A, B] {
  def apply(x: A) = fn(x)
}

object ReflectiveClosure {
  implicit def reflectClosure[A, B](f: Function1[A,B]): ReflectiveClosure[A, B] = macro Macros.reflectiveClosureImpl[A, B]
}

object Macros {
  def reflectiveClosureImpl[A, B](c: Context)(f: c.Expr[Function1[A, B]]) = {
    import c.universe._
    val u = treeBuild.mkRuntimeUniverseRef
    val m = EmptyTree
    val tree = c.Expr[scala.reflect.runtime.universe.Tree](Select(c.reifyTree(u, m, f.tree), newTermName("tree")))
    c.universe.reify(new ReflectiveClosure(tree.splice, f.splice))
  }
}

========

object Test extends App {
  implicit class PimpedList[T](val list: List[T]) {
    def query(predicate: ReflectiveClosure[T, Boolean]): List[T] = {
      println(predicate.tree)
      list filter predicate
    }
  }

  List(1, 2, 3).query((x: Int) => x % 2 == 0)
}

========

22:45 ~/Projects/Kepler_macrosnippet01/sandbox (topic/macrosnippet01)$ scalac Macros.scala && scalac Test.scala && scala Test
((x: Int) => x.$percent(2).$eq$eq(0))