Scala example source code file (Internals.scala)

This example Scala source code file (Internals.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, contextinternalapi, emptytree, hoftypingtransformer, macro, reflection, symbol, t, transformapi, transformer, tree, typingtransformapi

The Internals.scala Scala example source code

package scala.reflect.macros
package contexts

trait Internals extends scala.tools.nsc.transform.TypingTransformers {
  self: Context =>

  import global._

  lazy val internal: ContextInternalApi = new global.SymbolTableInternal with ContextInternalApi {
    val enclosingOwner = callsiteTyper.context.owner

    class HofTransformer(hof: (Tree, TransformApi) => Tree) extends Transformer {
      val api = new TransformApi {
        def recur(tree: Tree): Tree = hof(tree, this)
        def default(tree: Tree): Tree = superTransform(tree)
      }
      def superTransform(tree: Tree) = super.transform(tree)
      override def transform(tree: Tree): Tree = hof(tree, api)
    }

    def transform(tree: Tree)(transformer: (Tree, TransformApi) => Tree): Tree = new HofTransformer(transformer).transform(tree)

    class HofTypingTransformer(hof: (Tree, TypingTransformApi) => Tree) extends TypingTransformer(callsiteTyper.context.unit) { self =>
      currentOwner = callsiteTyper.context.owner
      curTree = EmptyTree
      localTyper = global.analyzer.newTyper(callsiteTyper.context.make(unit = callsiteTyper.context.unit))

      val api = new TypingTransformApi {
        def recur(tree: Tree): Tree = hof(tree, this)
        def default(tree: Tree): Tree = superTransform(tree)
        def atOwner[T](owner: Symbol)(op: => T): T = self.atOwner(owner)(op)
        def atOwner[T](tree: Tree, owner: Symbol)(op: => T): T = self.atOwner(tree, owner)(op)
        def currentOwner: Symbol = self.currentOwner
        def typecheck(tree: Tree): Tree = localTyper.typed(tree)
      }
      def superTransform(tree: Tree) = super.transform(tree)
      override def transform(tree: Tree): Tree = hof(tree, api)
    }

    def typingTransform(tree: Tree)(transformer: (Tree, TypingTransformApi) => Tree): Tree = new HofTypingTransformer(transformer).transform(tree)

    def typingTransform(tree: Tree, owner: Symbol)(transformer: (Tree, TypingTransformApi) => Tree): Tree = {
      val trans = new HofTypingTransformer(transformer)
      trans.atOwner(owner)(trans.transform(tree))
    }
  }
}