/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2009, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id$
package scala
/** 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
}
}