Scala example source code file (LazyEitherTest.scala)

This example Scala source code file (LazyEitherTest.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.

Learn more about this Scala project at its project page.

Java - Scala tags/keywords

bindrec, equal, int, lazyeither, lazyeitherequal, lazyeithertest, speclite

The LazyEitherTest.scala Scala example source code

package scalaz

import scalaz.scalacheck.ScalazProperties._
import scalaz.scalacheck.ScalazArbitrary._
import std.AllInstances._

object LazyEitherTest extends SpecLite {
  implicit def LazyEitherEqual[A: Equal, B: Equal]: Equal[LazyEither[A, B]] = new Equal[LazyEither[A, B]] {
    def equal(a: LazyEither[A, B], b: LazyEither[A, B]) =
      Equal[Either[A, B]].equal(a.toEither,b.toEither)
  }


  checkAll(equal.laws[LazyEither[Int,Int]])
  checkAll(monad.laws[LazyEither[Int, ?]])
  checkAll(monadError.laws[LazyEither[Int, ?], Int])
  checkAll(bindRec.laws[LazyEither[Int, ?]])
  checkAll(traverse.laws[LazyEither[Int, ?]])
  checkAll(associative.laws[LazyEither])
  checkAll(bitraverse.laws[LazyEither])

  "tail recursive tailrecM" in {
    val times = 10000

    val result =
      BindRec[LazyEither[Int, ?]].tailrecM[Int, Int] {
        i => LazyEither.lazyRight(if (i < 10000) \/.left(i + 1) else \/.right(i))
      }(0)
    result.getOrElse(0) must_=== times
  }
}