xeno-by

import shapeless._ 
object Test extends App { 
  implicitly[Generic.Aux[(Int, Char), Int :: Char :: HNil]] 
} 

[error] ~/Projects/shapeless-test/Test.scala:3: could not find implicit value for parameter e: shapeless.Generic.Aux[(Int, Char),shapeless.::[Int,shapeless.::[Char,shapeless.HNil]]] 
[error] implicitly[Generic.Aux[(Int, Char), Int :: Char :: HNil]] 
[error] ^ 

xeno-by

23:03 ~/Projects/sbt-example-paradise (master)$ sbt
[info] Loading project definition from /Users/xeno_by/Projects/sbt-example-paradise/project
[info] Updating {file:/Users/xeno_by/Projects/sbt-example-paradise/project/}sbt-example-paradise-build...
[info] Resolving org.fusesource.jansi#jansi;1.4 ...
[info] downloading http://repo1.maven.org/maven2/net/virtual-void/sbt-dependency-graph_2.10_0.13/0.7.4/sbt-dependency-graph-0.7.4.jar ...
[info] 	[SUCCESSFUL ] net.virtual-void#sbt-dependency-graph;0.7.4!sbt-dependency-graph.jar (986ms)
[info] downloading http://repo1.maven.org/maven2/com/github/mdr/ascii-graphs_2.10/0.0.3/ascii-graphs_2.10-0.0.3.jar ...
[info] 	[SUCCESSFUL ] com.github.mdr#ascii-graphs_2.10;0.0.3!ascii-graphs_2.10.jar (780ms)
[info] downloading http://repo1.maven.org/maven2/org/scala-lang/scala-library/2.10.1/scala-library-2.10.1.jar ...
[info] 	[SUCCESSFUL ] org.scala-lang#scala-library;2.10.1!scala-library.jar (2760ms)

xeno-by

import scala.reflect.macros.Context
import scala.language.experimental.macros
import scala.reflect.api.Liftable

object liftableMacro {
  implicit def liftableCaseClass[T]: Liftable[T] = macro impl
  def impl(c: Context): c.Tree = {
    import c.universe._
    val spliced: List[Tree] = List(q"???")
    val s = ""

xeno-by

[error] /Users/xeno_by/Projects/macros-playground/macros/src/main/scala/Macros.scala:50: Can't splice String(""), consider
[error]           Apply(Select(New(Ident(TermName(${""}))),
[error]                                             ^

xeno-by

// As I mentioned before, macros can do everything that the compiler can do by judicious application of casts.
// Here we get a reference to a typechecker servicing the expansion and from it - to the list of lexical scopes.
// Having that information at hand, we can report the list of variables in both lexical and "this" scopes.
// Since casts are involved here, there's no guarantee that this will work even in-between minor releases of Scala.
// Therefore I would advise going this route only if there are no workarounds for your particular use case.
// Please feel free to email me to ask for workarounds (but please don't leave comments here, because I don't get notified about them)

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

xeno-by

    private[this] val r1: reflect.runtime.universe.Tree = {
  import scala.reflect.api.Liftable;
  {
    final class $anon extends AnyRef with scala.reflect.api.Liftable[A] {
      def <init>(): <$anon: scala.reflect.api.Liftable[A]> = {
        $anon.super.<init>();
        ()
      };
      def apply(universe: scala.reflect.api.Universe, cc: A): universe.Tree = {
        val ttree: universe.TypeTree = universe.TypeTree(universe.typeOf[A]({

xeno-by

case class A()

object Test extends App {
  import Macros._
  import scala.reflect.runtime.universe._
  val c1 = A()
  val r1 = q"$c1"
}

xeno-by

import scala.reflect.macros.WhiteboxContext
import scala.language.experimental.macros
import scala.reflect.api.Liftable
import scala.reflect.macros.Universe
import scala.reflect.api.Position

object Macros {
  implicit def liftableCaseClass[T]: Liftable[T] = macro impl[T]
  def impl[T: c.WeakTypeTag](c: WhiteboxContext) = {
    import c.universe._

xeno-by

15:31 ~$ parse 'enum Day(foo: Int) = x'
[[syntax trees at end of parser]]// Scala source: tmpVbz6xn
package <empty> {
  class wrapper extends scala.AnyRef {
    def <init>() = {
      super.<init>();
      ()
    };
    enum.Day.update((foo: Int), x)
  }

xeno-by

09:32 ~$ prj
09:32 ~/Projects$ cd enum-paradise/
09:32 ~/Projects/enum-paradise (java-enums-via-macro-annotations)$ sbt
[info] Loading project definition from /Users/xeno_by/Projects/enum-paradise/project
[info] Set current project to root (in build file:/Users/xeno_by/Projects/enum-paradise/)
> clean
[success] Total time: 0 s, completed Nov 12, 2013 9:32:25 AM
> compile
[info] Updating {file:/Users/xeno_by/Projects/enum-paradise/}macros...
[info] Updating {file:/Users/xeno_by/Projects/enum-paradise/}root...