//
// 
// s_naught.pp
// 
// compute s_naught, the set of all vertices contained in an alternation
// reachable set.
//

*operation* Vertex_comma_list* compute_s_naught()
  *init* (@ new Vertex_comma_list @)
  *traverse* *from* Ar_Vertex_list *to* Ar_Vertex
  *wrapper* Ar_Vertex
    *suffix* (@ return_val->set_union(ar); @)