Introduction to the Design of Computational Calculi

homework.scala

trait RhoProcess

case class stopped() extends RhoProcess
case class input(variable : RhoName , channel : RhoName , p : RhoProcess) extends RhoProcess
case class output(channel : RhoName , q : RhoProcess) extends RhoProcess
case class concurrent(p : RhoProcess , q : RhoProcess) extends RhoProcess
case class execute(code : RhoName) extends RhoProcess

trait RhoName

case class name(p : RhoProcess ) extends RhoName

//Free names
// look up sets in scala  "+" union and diff and case calsses

def freeNames (P : RhoProcess) : Set[RhoName]  = 
  {
    P match {
      case stopped() => Set.empty //FN (0) = ∅ 
      case input(v,c,p) => Set(c) union (freeNames(p) diff Set(v)) //{x} ∪ (FN (P) \ {y})
      case output(c,q) => Set(c) union (freeNames(q))  //{x}∪FN (P)
      case concurrent(p,q) => freeNames(p) union freeNames(q) //FN (P) ∪FN (Q)
      case execute(c) => Set(c) //{x}
    }
  }

//Bound Names

//Structual equivalance