basic.scala

# A tiny DSL implementation for a minimal subset of BASIC in Scala
# Via http://www.nabble.com/-scala--ease-of-making-DSLs-in-Scala---nobody-cares-to22450638.html

class BasicClass {
  abstract sealed class BasicLine 
  case class PrintLine(num: Int, s: String) extends BasicLine
  case class GotoLine(num: Int, to: Int) extends BasicLine
  val lines = new scala.collection.mutable.HashMap[Int, BasicLine]
  case class linebuilder(num: Int) {
    def GOTO(to: Int) = lines(num) = GotoLine(num, to)
    def PRINT(s: String) = lines(num) = PrintLine(num, s)
  }
  private def gotoLine(line: Int) {
    lines(line) match {
      case PrintLine(_, s) => println(s); gotoLine(line + 10)
      case GotoLine(_, to) => gotoLine(to)
    }
  }
  def RUN {
    gotoLine(lines.keys.toList.first)
  }
  implicit def int2linebuilder(i: Int) = linebuilder(i)
}

basic_app.scala

object Playground extends BasicClass {
  def main(args: Array[String]) { 
    10 PRINT "SCALA ROCKS!"
    20 GOTO 10

    RUN
  }
}