// Expand Common parts of alternation classes
*operation* int expand_common(char* filename)
  *init* (@ 1 @)

  *wrapper* Cd_graph
    *prefix* (@ 
       cout << endl << "Expanding common parts ..." << endl;
       if (filename != NULL) {
         filebuf in_file;
         if (in_file.open(filename, input) != 0)
           cout << "sem-check: " << filename << " recreated." << endl;
         else
	     in_file.close();
         ofstream OutFile(filename);
         if (!OutFile) {
           cout << "sem-check: error: cannot open file " << filename << endl;
           return_val = 0;
         }
         else {
           OutFile << "// Common-expanded class dictionary."
                   << endl << endl;
         }
         
         Cd_graph* cdg = (Cd_graph*)this->g_copy();
         
         cdg->expand_common1();
       
         cdg->g_print(OutFile);
         
         cdg->g_delete();
         
         OutFile.close();
       }
     @)

*operation* void expand_common1()

  *traverse* *from* Cd_graph
             *to*   Alternat_ns
 
  *carry* *in* Cd_graph* graph = (@ this @)
          *along* *from* Cd_graph
                  *to*   Alternat_ns
                              
  *wrapper* Alternat_ns
    *prefix* (@ if (this->get_construct_ns() != NULL) {
                  this->expand_common2(graph, this->get_construct_ns());
                  this->get_construct_ns()->g_delete();
                  this->set_construct_ns(new Any_vertex_List);
                }
              @)
              
*operation* void expand_common2(Cd_graph* graph, Any_vertex_List* avl)

  *traverse* *from*    Alternat_ns
             *through* ->Alternat_ns,alternat_ns,*
             *to*      Term
             
  *wrapper* Term
    *prefix* (@ Adjacency* adjclass = graph->find_adjacency(this->get_vertex());
                adjclass->expand_common3(graph, avl);
              @)
              
*operation* void expand_common3(Cd_graph* graph, Any_vertex_List* avl)

  *traverse* *from* Adjacency
             *to*   {Construct_ns, Alternat_ns}
             
  *wrapper* Construct_ns
    *prefix* (@
                this->get_construct_ns()->
                      concatenate((Any_vertex_List*)avl->g_copy());
              @)
              
  *wrapper* Alternat_ns
    *prefix* (@ this->expand_common2(graph, avl);
              @)