// Check that each class is defined at least once.
*operation* int check_classes()
  *init* (@ 1 @)

  *traverse* *from*      Cd_graph
             *through*   ->Term,vertex,*
             *to*        Vertex

  *carry* *in* Cd_graph* graph = (@ this @)
          *along* *from* Cd_graph
                  *to*   Vertex

  *carry* *in* Vertex_Comma_list* params = (@ this->get_parameters() @)
	  *along* *from* Adjacency
		  *to*   Vertex


  *wrapper* Cd_graph
    *prefix* (@ cout << endl
                     << "Checking that every class is defined exactly once ..."
                     << endl;
              @)

  *wrapper* Adjacency
    *prefix* (@ if (graph->check_classes1(this->get_source()) > 1)
                  return_val = 0;
              @)

  *wrapper* Vertex
    *prefix* (@ if ((strcmp(this->get_vertex_name()->get_val(), 
		            "DemIdent")  != 0) &&
                    (strcmp(this->get_vertex_name()->get_val(), 
		            "DemReal")   != 0) &&
                    (strcmp(this->get_vertex_name()->get_val(), 
		            "DemNumber") != 0) &&
                    (strcmp(this->get_vertex_name()->get_val(), 
		            "DemString") != 0) &&
                    (strcmp(this->get_vertex_name()->get_val(), 
                    "DemText")   != 0)) {

                    if (graph->find_adjacency(this) == NULL) {
                      if ((params == NULL) ||
                          (!params->check_classes2(this))) {
                        return_val = 0;
                        cout << "sem-check: error: undefined class: '";
                        this->g_print();
                        cout << "' on line " 
                             << this->get_vertex_name()->get_line_number() 
                             << endl;
                    }
                  }
                }
              @)


// Check if class is defined more than once.
*operation* int check_classes1(Vertex *v)
  *init* (@ 0 @)

  *traverse* *from*      Cd_graph
             *through*   ->Adjacency,source,*
             *to*        Vertex

  *wrapper* Vertex
    *prefix* (@ if(this->g_equal(v)) {
                  return_val++;
                  if ((return_val > 1) && 
                      (this->get_vertex_name()->get_line_number() > 
                       v->get_vertex_name()->get_line_number())) {
                    cout << "sem-check: error: class '";
                    v->g_print();
                    cout << "' on line " 
                         << this->get_vertex_name()->get_line_number()
                         << " is redefined." << endl;
                  }
                }
              @)


// Check if class is defined as a parameter
*operation* int check_classes2(Vertex* v)
  *init* (@ 0 @)

  *traverse* *from* Vertex_Comma_list
             *to*   Vertex

  *wrapper* Vertex
    *prefix* (@ if (this->g_equal(v)) return_val = 1;
              @)