| career | drupal | java | mac | mysql | perl | scala | uml | unix  

Scala example source code file (TriState.scala)

This example Scala source code file (TriState.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; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

anyval, boolean, false, int, not, tristate, true, unknown

The TriState.scala Scala example source code

package scala
package reflect
package internal
package util

import scala.language.implicitConversions

import TriState._

/** A simple true/false/unknown value, for those days when
 *  true and false don't quite partition the space.
final class TriState private (val value: Int) extends AnyVal {
  def isKnown = this != Unknown
  def booleanValue = this match {
    case True  => true
    case False => false
    case _     => sys.error("Not a Boolean value")

object TriState {
  implicit def booleanToTriState(b: Boolean): TriState = if (b) True else False

  val Unknown = new TriState(-1)
  val False   = new TriState(0)
  val True    = new TriState(1)

Other Scala source code examples

Here is a short list of links related to this Scala TriState.scala source code file:

... this post is sponsored by my books ...

#1 New Release!

FP Best Seller


new blog posts


Copyright 1998-2021 Alvin Alexander,
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.