306   // given a state and a character, what is the set of 

   306   // given a state and a character, what is the set of 

   307   // next states? if there is none => empty set

   307   // next states? if there is none => empty set

   308   def next(q: A, c: C) : Set[A] = 

   308   def next(q: A, c: C) : Set[A] = 

   309     Try(delta(q, c)) getOrElse Set[A]() 

   309     Try(delta(q, c)) getOrElse Set[A]() 

   310 

   310 

   311   // depth-first version of accepts

   314   // depth-first version of accepts

   312   def search(q: A, s: List[C]) : Boolean = s match {

   315   def search(q: A, s: List[C]) : Boolean = s match {

   313     case Nil => fins(q)

   316     case Nil => fins(q)

   314     case c::cs => next(q, c).exists(search(_, cs))

   317     case c::cs => next(q, c).exists(search(_, cs))

   315   }

   318   }