Experimenting with Scala

This is my first useful Scala program. It was ported from a Python program (see below). In 1993 I wrote an equivalent in Modula-2 ;-)

import scala.io.Source;
import java.io.File;
import scala.util.Random;

object voc {
  def train(lst : List[Tuple2[String, String]]) : Unit = {
    println();
    if (lst.length == 0) {
      println(":-D");
      return;
    }

    val shuffled = Random.shuffle(lst);
    val current = shuffled.head;
    println(">>> " + current._1);
    var line = Console.readLine();
    if (line == current._2) {
      println("correct");
      train(shuffled.tail);
    } else {
      print("\007");
      println("wrong - correct is: " + current._2);
      train(shuffled);
    }
  }

  def main(args: Array[String]) {
    val lst = Source.fromFile(new File(args(0))).getLines()
          .map { s => s.split("\t") }
          .filter( l => l.length == 2 )
          .map (l => Tuple2(l.head, l.last))
          .toList;

    train(lst);
  }
}

Python version:

from __future__ import with_statement
import random
import sys

def train(lst):
    while len(lst) > 0:
        random.shuffle(lst)

        lang1, lang2 = lst[0]

        print ">>>", lang1
        try:
            answer = raw_input("answer: ").strip()
        except EOFError:
            # ^Z pressed, ignore
            continue

        if answer == lang2:
            print "correct"
            lst = lst[1:]
        else:
            print chr(7)
            print "wrong - correct is =>", lang2

        print
        print

    print ":-D"

def main():
    filename = sys.argv[1]

    lst = []
    for line in open(filename):
        line = line.strip()
        if not line:
            continue
        parts = line.split("\t")
        assert len(parts) == 2
        lst.append(parts)

    train(lst)


if __name__ == "__main__":
    main()