テキスト読み込み２

gistfile1.scala

// Scala 実践プログラミングの grep の記事を参考にしたバージョン

import scala.io.Source

object CheckLog {

  case class Args(
    filename: String,
    exp: String
  )

  def main(args: Array[String]) {

    val argsOption = parseArgs(args.toList)

    val s = Source.fromFile(argsOption.get.filename,"UTF8")
    val exp = argsOption.get.exp
    val p = exp.r

    try {
      val lines = s.getLines.takeWhile(_ != null).toList
      val linesWithNum = lines.zipWithIndex.map{ case(line,i) => (i + 1, line) }

      val result = linesWithNum.filter{ case(_, line) => line.matches(exp) }

      for((lnum, line) <- result) printf("%d: %s %s%n", lnum, line, p.findFirstMatchIn(line).get.matched)
      printf("matched = %d%n", result.length)
    } finally {
      s.close
    }
  }

  def parseArgs(args: List[String]): Option[Args] = {

    var fileName = "./takuya71.log"
    var exp = ".*error|hoge"

    @scala.annotation.tailrec
    def parseArgsHelper(args: List[String]): Args = {
      args match {
        case "-f" :: x :: rest => {
          fileName = x
          parseArgsHelper(rest)
        }
        case "-e" :: x :: rest => {
          exp = x
          parseArgsHelper(rest)
        }
        case _ => Args(fileName,exp)
    }
  }

  try { 
    Some(parseArgsHelper(args))
  } 
   catch {
     case _ =>  None }
  }

}