unapply tuple extraction

extractor.scala

import scala.util.matching.Regex
import scala.util.matching.Regex.Match

trait RegexExtractor[M] {
  def pattner: Regex
  
  def unapply(line: String): Option[M] = {
    pattern.findFirstMatchIn(line) map { matches =>
      extractMatches(matches)
    }
  }
  
  def extractMatches(matchData: Match): M
}

object OverridingExtractor extends RegexExtractor[(String, Int)] {
  val pattern = "([a-z]+): ([0-9]+)".r
  
  override def unapply(line: String) = {
    pattern.findFirstMatchIn(line) map { matches =>
      (matches.group(1), matches.group(2).toInt)
    }
  }
  
  override def extractMatches(matchData: Match) = {
    (matchData.group(1), matchData.group(2).toInt)
  }
}

object MethodCallingExtractor extends RegexExtractor[(String, Int)] {
  val pattern = "([a-z]+): ([0-9]+)".r
  
  override def extractMatches(matchData: Match) = {
    (matchData.group(1), matchData.group(2).toInt)
  }
}

"age: 33" match {
  case OverridingExtractor(label, age) =>
    // label = "age", age = 33
  case MethodCallingExtractor(label, age) =>
    // label = ("age", 33), age = <no type infered> compiler error MethodCallingExtractor.type does not take parameters
}