Scala example source code file (OrderingInstances.scala)

This example Scala source code file (OrderingInstances.scala) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Scala by Example" ^TM.

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Java - Scala tags/keywords

int, monoid, orderingfunctions, orderinginstances, sordering, toscalazorderfromordering

The OrderingInstances.scala Scala example source code

package scalaz
package std
package math

import scala.math.{Ordering => SOrdering}
import scalaz.Ordering


trait OrderingInstances {
  def orderingMonoid[A] = new Monoid[SOrdering[A]] {
    def append(f1: SOrdering[A], f2: => SOrdering[A]) = new SOrdering[A] {
      def compare(x: A, y: A): Int = f1.compare(x, y) match {
        case 0 => f2.compare(x, y)
        case o => o
      }
    }
    def zero = new SOrdering[A] {
      def compare(x: A, y: A): Int = 0
    }
  }
}

trait OrderingFunctions {
  final def ToScalazOrderFromOrdering[A](oa: SOrdering[A]): scalaz.Order[A] = new scalaz.Order[A] {
    def order(x: A, y: A): Ordering = Ordering.fromInt(oa.compare(x, y))
  }
}

object ordering extends OrderingInstances