Scala example source code file (PresentationCompilerRequestsWorkingMode.scala)

This example Scala source code file (PresentationCompilerRequestsWorkingMode.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

boolean, compiler, nsc, position, reflection, response, seq, some, sourcefile, string, t, testmarker, unit, utilities

The PresentationCompilerRequestsWorkingMode.scala Scala example source code

package scala.tools.nsc
package interactive
package tests.core

import scala.reflect.internal.util.Position
import scala.reflect.internal.util.SourceFile

trait PresentationCompilerRequestsWorkingMode extends TestResources {

  protected def synchronousRequests: Boolean

  protected def askAllSources[T] = if (synchronousRequests) askAllSourcesSync[T] _ else askAllSourcesAsync[T] _

  /** Perform an operation on all sources at all positions that match the given
   *  `marker`. For instance, askAllSources(TypeMarker)(askTypeAt)(println) would
   *  ask the type at all positions marked with `TypeMarker.marker` and println the result.
   */
  private def askAllSourcesAsync[T](marker: TestMarker)(askAt: Position => Response[T])(f: (Position, T) => Unit) {
    val positions = allPositionsOf(str = marker.marker)
    val responses = for (pos <- positions) yield askAt(pos)

    for ((pos, r) <- positions zip responses) withResponse(pos, r)(f)
  }

  /** Synchronous version of askAllSources. Each position is treated in turn, waiting for the
   *  response before going to the next one.
   */
  private def askAllSourcesSync[T](marker: TestMarker)(askAt: Position => Response[T])(f: (Position, T) => Unit) {
    val positions = allPositionsOf(str = marker.marker)
    for (pos <- positions) withResponse(pos, askAt(pos))(f)
  }

  /** All positions of the given string in all source files. */
  private def allPositionsOf(srcs: Seq[SourceFile] = sourceFiles, str: String): Seq[Position] =
    for (s <- srcs; p <- positionsOf(s, str)) yield p

  /** Return all positions of the given str in the given source file. */
  private def positionsOf(source: SourceFile, str: String): Seq[Position] = {
    val buf = new scala.collection.mutable.ListBuffer[Position]
    var pos = source.content.indexOfSlice(str)
    while (pos >= 0) {
      buf += source.position(pos - 1) // we need the position before the first character of this marker
      pos = source.content.indexOfSlice(str, pos + 1)
    }
    buf.toList
  }

  private def withResponse[T](pos: Position, response: Response[T])(f: (Position, T) => Unit) {
    /** Return the filename:line:col version of this position. */
    def showPos(pos: Position): String =
      "%s:%d:%d".format(pos.source.file.name, pos.line, pos.column)

    response.get(TIMEOUT) match {
      case Some(Left(t)) =>
        f(pos, t)
      case None =>
        println("TIMEOUT: " + showPos(pos))
      case Some(r) =>
        println("ERROR: " + r)
    }
  }
}