Scala example source code file (Phase.scala)

This example Scala source code file (Phase.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

any, boolean, error, id, int, long, nophase, phase, somephase, string

The Phase.scala Scala example source code

/* NSC -- new Scala compiler
 * Copyright 2005-2013 LAMP/EPFL
 * @author  Martin Odersky
 */

package scala
package reflect
package internal

abstract class Phase(val prev: Phase) {
  if ((prev ne null) && (prev ne NoPhase))
    prev.nx = this

  type Id = Int
  val id: Id = if (prev eq null) 0 else prev.id + 1

  /** New flags visible after this phase has completed */
  def nextFlags: Long = 0l

  /** New flags visible once this phase has started */
  def newFlags: Long = 0l

  val fmask = (
    if (prev eq null) Flags.InitialFlags
    else prev.flagMask | prev.nextFlags | newFlags
  )
  def flagMask: Long = fmask

  private var nx: Phase = NoPhase

  // does anyone rely on next == this for terminus?
  def next: Phase = if (nx eq NoPhase) this else nx
  def hasNext = next != this
  // this definition excludes the terminal phase
  //def iterator = Iterator.iterate(this)(_.nx) takeWhile (p => p.next != p)
  def iterator = Iterator.iterate(this)(_.nx) takeWhile (_ ne NoPhase)

  def name: String
  def description: String = name
  // Will running with -Ycheck:name work?
  def checkable: Boolean = true
  def specialized: Boolean = false
  def erasedTypes: Boolean = false
  def flatClasses: Boolean = false
  def refChecked: Boolean = false

  /** This is used only in unsafeTypeParams, and at this writing is
   *  overridden to false in parser, namer, typer, and erasure. (And NoPhase.)
   */
  def keepsTypeParams = true
  def run(): Unit

  override def toString() = name
  override def hashCode = id.## + name.##
  override def equals(other: Any) = other match {
    case x: Phase   => id == x.id && name == x.name
    case _          => false
  }
}

object NoPhase extends Phase(null) {
  def name = "<no phase>"
  override def keepsTypeParams = false
  def run() { throw new Error("NoPhase.run") }
}

object SomePhase extends Phase(NoPhase) {
  def name = "<some phase>"
  def run() { throw new Error("SomePhase.run") }
}