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import scala.io.Source.fromFile

object BF{
  def main(args:Array[String]) = {
    if(args.size == 0) print("scala BF [sourcecode filename]")
    else
    args.foreach{f=> (new Machine).interpret(fromFile(f).mkString("")) }
  }
}

object Machine {
  final val MEM = 0xffffff
  final val VAL = 0xff
}

class Machine{
  var _p = 0
  val _mem = new Array[int](Machine.MEM)
  def p_=(v:int) = _p = v&Machine.MEM
  def p = _p
  def mem_=(v:int) = _mem(p)=v&Machine.VAL
  def mem = _mem(p)

  def abort = error("Missing corresponding parenthesis.")

  def interpret(code:String):unit = interpret(code.toArray)
  def interpret(code:Array[char]):unit = {
    val (s,m) = ((List[int](), List[(int,int)]()) /: code.zipWithIndex){
      (r,c) => c._1 match {
        case '[' => (c._2::r._1, r._2)
        case ']' => r._1 match {
          case x::xs => (xs, (x,c._2)::(c._2,x)::r._2)
          case _ => abort
        }
        case _   => r
    }}
    if(s.size > 0) abort
    val parenMap = Map(m:_*)

    var i = -1;while({i=i+1;i<code.size}) code(i) match {
      case '>' => p = p+1
      case '<' => p = p-1
      case '+' => mem = mem+1
      case '-' => mem = mem-1
      case '.' => print(mem.asInstanceOf[char])
      case ',' => mem = readChar.asInstanceOf[int]
      case '[' if mem == 0 => i = parenMap(i)
      case ']' if mem != 0 => i = parenMap(i)
      case _   => ()
    }
  }
}