minimal scalaz monoid example

monoidExample.scala

import scalaz._            // general scalaz support
import syntax.monoid._     // monoid syntax as used below
import std.anyVal._        // some instances to work with
import std.list._          // some more instances
import std.option._        // some more instances
import syntax.std.option._ // postfix methods for options

object monoidExample {
  val res0 = ∅[Int]        // or: mzero[Int]
  val res1 = 3 |+| 4       // or: 3 `mappend` 4

  val res2 = ∅[List[Int]]
  val res3 = List(1, 2, 3) |+| List(4, 5)
  
  val res4 = none[Option[Int]]
  val res5 = 3.some |+| 4.some
  val res6 = 3.some |+| none
}