Scala example source code file (CaseInsensitive.scala)

This example Scala source code file (CaseInsensitive.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

any, boolean, caseinsensitive, caseinsensitiveinstances, caseinsensitiveshow, equal, foldcase, foldcaseinstances, monoid, need, order, show, stringfoldcase

The CaseInsensitive.scala Scala example source code

package scalaz

sealed abstract class CaseInsensitive[A] {
  val original: A
  def foldedCase: A

  final def map[B: FoldCase](f: A => B): CaseInsensitive[B] = CaseInsensitive(f(original))

  final override def equals(other: Any): Boolean = other match {
    case that: CaseInsensitive[_] => foldedCase == that.foldedCase
    case _ => false
  }

  private[this] val hash = Need(foldedCase.hashCode)

  final override def hashCode: Int = hash.value
}

object CaseInsensitive extends CaseInsensitiveInstances {
  def apply[A](a: A)(implicit A: FoldCase[A]): CaseInsensitive[A] = mk(a, A.foldCase(a))

  private[scalaz] def mk[A](a: A, fc: => A): CaseInsensitive[A] = new CaseInsensitive[A] {
    val original = a
    private[this] val fcCache = Need(fc)
    def foldedCase = fcCache.value
  }
}

sealed abstract class CaseInsensitiveInstances {
  implicit def CaseInsensitiveMonoid[A: FoldCase : Monoid]: Monoid[CaseInsensitive[A]] =
    new Monoid[CaseInsensitive[A]] {
      def zero = CaseInsensitive.mk(Monoid[A].zero, Monoid[A].zero)
      def append(a: CaseInsensitive[A], b: => CaseInsensitive[A]) =
        CaseInsensitive.mk(Semigroup[A].append(a.original, b.original), Semigroup[A].append(a.foldedCase, b.foldedCase))
    }

  implicit def CaseInsensitiveEqual[A: Equal]: Equal[CaseInsensitive[A]] =
    new Equal[CaseInsensitive[A]] {
      def equal(a: CaseInsensitive[A], b: CaseInsensitive[A]) =
        Equal[A].equal(a.foldedCase, b.foldedCase)
    }

  implicit def CaseInsensitiveOrder[A: Order]: Order[CaseInsensitive[A]] =
    new Order[CaseInsensitive[A]] {
      def order(a: CaseInsensitive[A], b: CaseInsensitive[A]) = Order[A].order(a.foldedCase, b.foldedCase)
    }

  implicit def CaseInsensitiveShow[A: Show]: Show[CaseInsensitive[A]] =
    new Show[CaseInsensitive[A]] {
      override def show(a: CaseInsensitive[A]) = Show[A].show(a.original)
    }
}

trait FoldCase[A] {
  def foldCase(a: A): A
}

object FoldCase extends FoldCaseInstances

sealed abstract class FoldCaseInstances {
  implicit val StringFoldCase: FoldCase[String] = new FoldCase[String] {
    def foldCase(s: String) = s.toLowerCase
  }
}