Scala example source code file (Show.scala)

This example Scala source code file (Show.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

contravariant, cord, show, string

The Show.scala Scala example source code

package scalaz

////
/**
 * A typeclass for conversion to textual representation, done via
 * [[scalaz.Cord]] for efficiency.
 */
////
trait Show[F]  { self =>
  ////
  def show(f: F): Cord = Cord(shows(f))
  def shows(f: F): String = show(f).toString

  // derived functions
  ////
  val showSyntax = new scalaz.syntax.ShowSyntax[F] { def F = Show.this }
}

object Show {
  @inline def apply[F](implicit F: Show[F]): Show[F] = F

  ////

  def showFromToString[A]: Show[A] = new Show[A] {
    override def shows(f: A): String = f.toString
  }

  /** For compatibility with Scalaz 6 */
  def showA[A]: Show[A] = showFromToString[A]

  def show[A](f: A => Cord): Show[A] = new Show[A] {
    override def show(a: A): Cord = f(a)
  }

  def shows[A](f: A => String): Show[A] = new Show[A] {
    override def shows(a: A): String = f(a)
  }

  implicit val showContravariant: Contravariant[Show] = new Contravariant[Show] {
    def contramap[A, B](r: Show[A])(f: B => A): Show[B] = new Show[B] {
      override def show(b: B): Cord = r.show(f(b))
    }
  }

  ////
}