package m

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

object Level extends Enumeration {
  val Error = Value(5)
}

object Logger {
  def error(message: String): Unit = macro LoggerMacros.error
}

private object LoggerMacros {

  type LoggerContext = Context { type PrefixType = Logger.type }

  def error(c: LoggerContext)(message: c.Expr[String]): c.Expr[Unit] =
    log(c)(c.reify(Level.Error), message)

  private def log(c: LoggerContext)(level: c.Expr[Level.Value], message: c.Expr[String]): c.Expr[Unit] = 
    if (level.eval.id < 4) // TODO Remove hack!
      c.reify(())
    else {
      c.reify(println(message.eval))
    }
}

scala> import m._
import m._

scala> Logger.error("err")
<console>:11: error: exception during macro expansion: 
scala.tools.nsc.ToolBoxes$ToolBox$ToolBoxError: reflective compilation has failed: 

object Error is not a member of package Level
	at scala.tools.nsc.ToolBoxes$ToolBox.runExpr(ToolBoxes.scala:48)
	at scala.reflect.api.Exprs$Expr.eval(Exprs.scala:15)
	at m.LoggerMacros$.log(M.scala:22)
	at m.LoggerMacros$.error(M.scala:19)

              Logger.error("err")
                          ^