private void
        build_function_structure()
        {
                if(log_level >= 4) log.log(4, key, "build_function_structure called.", "\n");
                TreeMap<Integer,Variable> temp = new TreeMap<>();
                HashMap<Integer,Variable> helper;
                int count = 0;
                for (String context : function_startpoint.keySet()) {
                        for (Variable variable : context_varname_var.get(context).values()) {
                                if (variable.get_var_type().equals("VAR_INPUT")){
                                        temp.put(new Integer(variable.get_id()), variable);
                                }
                        }

                        for (Variable variable_sorted : temp.values()) {
                                helper = new HashMap<>();
                                helper.put(new Integer(count), variable_sorted);
                                functioname_inputid_var.put(context, helper);
                        }
                        count = 0;
                        temp = new TreeMap<>();
                }
        }