Scala example source code file (TemplateTransformComponent.scala)

This example Scala source code file (TemplateTransformComponent.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

compilationunit, global, list, new, plugincomponent, templatetransformcomponent, templatetransformer, templatetransformer, transform, transform, transformer, tree, tree, typing

The Scala TemplateTransformComponent.scala source code

package plugintemplate

import scala.tools.nsc._
import scala.tools.nsc.plugins.PluginComponent
import scala.tools.nsc.transform.Transform
// import scala.tools.nsc.transform.TypingTransformers

/** This class implements a plugin component using tree transformers. If
 *  a <code>Typer is needed during transformation, the component
 *  should mix in <code>TypingTransformers. This provides a local
 *  variable <code>localTyper: Typer that is always updated to
 *  the current context.
 *
 *  @todo Adapt the name of this class to the plugin, and implement it.
 */
class TemplateTransformComponent(val global: Global) extends PluginComponent
                                                     // with TypingTransformers
                                                     with Transform {
  import global._
  import global.definitions._

  val runsAfter = List[String]("refchecks")
  /** The phase name of the compiler plugin
   *  @todo Adapt to specific plugin.
   */
  val phaseName = "plugintemplatetransform"

  def newTransformer(unit: CompilationUnit) = new TemplateTransformer

  /** The tree transformer that implements the behavior of this
   *  component. Change the superclass to <code>TypingTransformer
   *  to make a local typechecker <code>localTyper available.
   *
   *  @todo Implement.
   */
  class TemplateTransformer extends /*Typing*/ Transformer {
    /** When using <code>preTransform, each node is
     *  visited before its children.
     */
    def preTransform(tree: Tree): Tree = tree match {
      case _ => tree
    }

    /** When using <code>postTransform, each node is
     *  visited after its children.
     */
    def postTransform(tree: Tree): Tree = tree match {
      case New(tpt) =>
          println("post-transforming new "+ tpt)
          tree
      case _ => tree
    }

    override def transform(tree: Tree): Tree = {
      postTransform(super.transform(preTransform(tree)))
    }
  }
}