// Check to see if each Alternative Term of an alternation production
// is not a repetition class and that it is not duplicately defined in
// inherited alternation classes.
*operation* int check_alternatives()
  *init* (@ 1 @)

  *traverse* *from*    Cd_graph
             *through* ->Alternat_ns,*,Term_Bar_list
             *to-stop* Term

  *carry* *in* Vertex* src = (@ this->get_source() @)
          *along* *from* Adjacency
                  *to*   Term

  *carry* *in* Term_Bar_list* tbl = (@ this @)
          *along* *from* Term_Bar_list
                  *to*   Term

  *carry* *in* Cd_graph* graph = (@ this @)
          *along* *from* Cd_graph
                  *to*   Term
                  
  *wrapper* Cd_graph
    *prefix* (@ cout << endl << "Checking that all alternatives are defined "
                     << "as either" << endl
                     << "\tconstruction classes or alternation classes that"
                     << endl << "\twill eventually be defined by "
                     << "construction classes ..." << endl;
              @)

  *wrapper* Term
    *prefix* (@ Adjacency* adjclass = graph->find_adjacency(this->get_vertex());
                if (adjclass->check_alternatives1()) {
                  cout << "sem-check: error: on line "
                       << this->find_line_number()
                       << "  ";
                  this->get_vertex()->g_print();
                  cout << ", a repetition class," << endl
                       << "\tcannot be an alternative of ";
                  src->g_print();
                  cout << "." << endl; 
                  return_val = 0;
                }

                if (adjclass->check_alternatives2(graph, src, tbl)) {
                  return_val = 0;
                }
              @)

// Check to see if this adjacency is a repetition class.
*operation* int check_alternatives1()
  *init* (@ 0 @)

  *traverse* *from*      Adjacency
             *to-stop*   Repetit_n

  *wrapper* Repetit_n
    *prefix* (@ return_val = 1; @)


// Check to see if an alternative is duplicated.
*operation* int check_alternatives2(Cd_graph* graph, Vertex* src, 
                                    Term_Bar_list* tbl)
  *init* (@ 0 @)

  *traverse* *from*    Adjacency
             *through* ->Alternat_ns,*,Term_Bar_list
             *to-stop* Term 

  *wrapper* Term
    *prefix* (@ if (tbl->check_alternatives3(src, this->get_vertex()))
                  return_val = 1;
                else 
                  if (graph->find_adjacency(this->get_vertex())
                           ->check_alternatives2(graph, src, tbl))
                    return_val = 1;
              @)

*operation* int check_alternatives3(Vertex* src, Vertex* v)
  *init* (@ 0 @)

  *traverse* *from*    Term_Bar_list
             *to-stop* Term

  *wrapper* Term
    *prefix* (@ if (this->get_vertex()->g_equal(v)) {
                  cout << "sem-check: error: on line "
                       << this->find_line_number()
                       << "  ";
                  this->get_vertex()->g_print();
                  cout << "is duplicated as an alternative of ";
                  src->g_print();
                  cout << "." << endl;
                  return_val = 1;
                }
              @)