Scala example source code file (PartiallyOrdered.scala)

This example Scala source code file (PartiallyOrdered.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

a, b, boolean, option, partiallyordered, some

The PartiallyOrdered.scala Scala example source code

/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2003-2013, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */



package scala
package math

/** A class for partially ordered data.
 *
 *  @author  Martin Odersky
 *  @version 1.0, 23/04/2004
 */
trait PartiallyOrdered[+A] {

  /** Result of comparing `'''this'''` with operand `that`.
   *  Returns `None` if operands are not comparable.
   *  If operands are comparable, returns `Some(x)` where
   *  - `x < 0`    iff   `'''this''' < that`
   *  - `x == 0`   iff   `'''this''' == that`
   *  - `x > 0`    iff   `'''this''' > that`
   */
  def tryCompareTo [B >: A <% PartiallyOrdered[B]](that: B): Option[Int]

  def <  [B >: A <% PartiallyOrdered[B]](that: B): Boolean =
    (this tryCompareTo that) match {
      case Some(x) if x < 0 => true
      case _ => false
    }
  def >  [B >: A <% PartiallyOrdered[B]](that: B): Boolean =
    (this tryCompareTo that) match {
      case Some(x) if x > 0 => true
      case _ => false
    }
  def <= [B >: A <% PartiallyOrdered[B]](that: B): Boolean =
    (this tryCompareTo that) match {
      case Some(x) if x <= 0 => true
      case _ => false
    }
  def >= [B >: A <% PartiallyOrdered[B]](that: B): Boolean =
    (this tryCompareTo that) match {
      case Some(x) if x >= 0 => true
      case _ => false
    }
}