Scala example source code file (Quasiquotes.scala)

This example Scala source code file (Quasiquotes.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

context, couldn't, list, literal, macro, parsers, quasiquotes, reflection, reifiers, runtime, string, tree, unknown

The Quasiquotes.scala Scala example source code

package scala.tools.reflect
package quasiquotes

import scala.reflect.macros.runtime.Context

abstract class Quasiquotes extends Parsers
                              with Holes
                              with Placeholders
                              with Reifiers {
  val c: Context
  val global: c.universe.type = c.universe
  import c.universe._

  def debug(msg: => String): Unit =
    if (settings.Yquasiquotedebug.value) println(msg)

  lazy val (universe: Tree, args, parts, parse, reify, method) = c.macroApplication match {
    case Apply(build.SyntacticTypeApplied(Select(Select(Apply(Select(universe0, _), List(Apply(_, parts0))), interpolator0), method0), _), args0) =>
      debug(s"parse prefix:\nuniverse=$universe0\nparts=$parts0\ninterpolator=$interpolator0\nmethod=$method0\nargs=$args0\n")
      val parts1 = parts0.map {
        case lit @ Literal(Constant(s: String)) => s -> lit.pos
        case part => c.abort(part.pos, "Quasiquotes can only be used with literal strings")
      }
      val reify0 = method0 match {
        case nme.apply   => new ApplyReifier().reifyFillingHoles(_)
        case nme.unapply => new UnapplyReifier().reifyFillingHoles(_)
        case other       => global.abort(s"Unknown quasiquote api method: $other")
      }
      val parse0 = interpolator0 match {
        case nme.q       => TermParser.parse(_)
        case nme.tq      => TypeParser.parse(_)
        case nme.cq      => CaseParser.parse(_)
        case nme.pq      => PatternParser.parse(_)
        case nme.fq      => ForEnumeratorParser.parse(_)
        case other       => global.abort(s"Unknown quasiquote flavor: $other")
      }
      (universe0, args0, parts1, parse0, reify0, method0)
    case _ =>
      global.abort(s"Couldn't parse call prefix tree ${c.macroApplication}.")
  }

  lazy val u = universe // shortcut
  lazy val universeTypes = new definitions.UniverseDependentTypes(universe)

  def expandQuasiquote = {
    debug(s"macro application:\n${c.macroApplication}\n")
    debug(s"code to parse:\n$code\n")
    val tree = parse(code)
    debug(s"parsed:\n${showRaw(tree)}\n$tree\n")
    val reified = reify(tree)
    def sreified =
      reified
        .toString
        .replace("scala.reflect.runtime.`package`.universe.internal.reificationSupport.", "")
        .replace("scala.reflect.runtime.`package`.universe.", "")
        .replace("scala.collection.immutable.", "")
    debug(s"reified tree:\n$sreified\n")
    reified
  }
}