tofu.internal.CachedMatcher.scala Maven / Gradle / Ivy

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Opinionated Set of tool for functional programming in scala

There is a newer version: 0.9.2

package tofu.internal

private [tofu] final case class CachedMatcher[-A, +B](f: A => Option[B]) extends PartialFunction[A, B] {
  private[this] var cachedInput: Option[A]  = None
  private[this] var cachedOutput: Option[B] = None
  @inline private[this] def calc(input: A): Option[B] = {
    if (!cachedInput.contains(input)) {
      cachedInput = Some(input)
      cachedOutput = f(input)
    }
    cachedOutput
  }

  def isDefinedAt(x: A): Boolean = calc(x).isDefined
  def apply(x: A): B             = calc(x).get

}