text: 
  //  (C) Copyright Edward Diener 2011-2015
  //  Use, modification and distribution are subject to the Boost Software License,
  //  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  //  http://www.boost.org/LICENSE_1_0.txt).
  
  #if !defined(BOOST_VMD_DETAIL_MODS_HPP)
  #define BOOST_VMD_DETAIL_MODS_HPP
  
  #include <boost/preprocessor/arithmetic/inc.hpp>
  #include <boost/preprocessor/comparison/equal.hpp>
  #include <boost/preprocessor/comparison/greater.hpp>
  #include <boost/preprocessor/control/iif.hpp>
  #include <boost/preprocessor/control/while.hpp>
  #include <boost/preprocessor/punctuation/is_begin_parens.hpp>
  #include <boost/preprocessor/tuple/elem.hpp>
  #include <boost/preprocessor/tuple/pop_front.hpp>
  #include <boost/preprocessor/tuple/push_back.hpp>
  #include <boost/preprocessor/tuple/replace.hpp>
  #include <boost/preprocessor/tuple/size.hpp>
  #include <boost/preprocessor/variadic/to_tuple.hpp>
  #include <boost/vmd/identity.hpp>
  #include <boost/vmd/is_empty.hpp>
  #include <boost/vmd/is_type.hpp>
  #include <boost/vmd/detail/modifiers.hpp>
  
  #define BOOST_VMD_DETAIL_MODS_NO_RETURN 0
  #define BOOST_VMD_DETAIL_MODS_RETURN 1
  #define BOOST_VMD_DETAIL_MODS_RETURN_TUPLE 2
  #define BOOST_VMD_DETAIL_MODS_RETURN_ARRAY 3
  #define BOOST_VMD_DETAIL_MODS_RETURN_LIST 4
  #define BOOST_VMD_DETAIL_MODS_NO_AFTER 0
  #define BOOST_VMD_DETAIL_MODS_RETURN_AFTER 1
  #define BOOST_VMD_DETAIL_MODS_NO_INDEX 0
  #define BOOST_VMD_DETAIL_MODS_RETURN_INDEX 1
  #define BOOST_VMD_DETAIL_MODS_NO_ONLY_AFTER 0
  #define BOOST_VMD_DETAIL_MODS_RETURN_ONLY_AFTER 1
  
  #define BOOST_VMD_DETAIL_MODS_TUPLE_RETURN 0
  #define BOOST_VMD_DETAIL_MODS_TUPLE_AFTER 1
  #define BOOST_VMD_DETAIL_MODS_TUPLE_INDEX 2
  #define BOOST_VMD_DETAIL_MODS_TUPLE_OTHER 3
  #define BOOST_VMD_DETAIL_MODS_TUPLE_ONLY_AFTER 4
  #define BOOST_VMD_DETAIL_MODS_TUPLE_TYPE 5
  
  #define BOOST_VMD_DETAIL_MODS_DATA_INPUT 0
  #define BOOST_VMD_DETAIL_MODS_DATA_INDEX 1
  #define BOOST_VMD_DETAIL_MODS_DATA_SIZE 2
  #define BOOST_VMD_DETAIL_MODS_DATA_RESULT 3
  #define BOOST_VMD_DETAIL_MODS_DATA_ALLOW 4
  
  #define BOOST_VMD_DETAIL_MODS_STATE_INPUT(state) \
      BOOST_PP_TUPLE_ELEM(BOOST_VMD_DETAIL_MODS_DATA_INPUT,state) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_STATE_INDEX(state) \
      BOOST_PP_TUPLE_ELEM(BOOST_VMD_DETAIL_MODS_DATA_INDEX,state) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_STATE_SIZE(state) \
      BOOST_PP_TUPLE_ELEM(BOOST_VMD_DETAIL_MODS_DATA_SIZE,state) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_STATE_RESULT(state) \
      BOOST_PP_TUPLE_ELEM(BOOST_VMD_DETAIL_MODS_DATA_RESULT,state) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_STATE_ALLOW(state) \
      BOOST_PP_TUPLE_ELEM(BOOST_VMD_DETAIL_MODS_DATA_ALLOW,state) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_STATE_IS_ALLOW_ALL(state) \
      BOOST_VMD_DETAIL_IS_ALLOW_ALL(BOOST_VMD_DETAIL_MODS_STATE_ALLOW(state)) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_STATE_IS_ALLOW_RETURN(state) \
      BOOST_VMD_DETAIL_IS_ALLOW_RETURN(BOOST_VMD_DETAIL_MODS_STATE_ALLOW(state)) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_STATE_IS_ALLOW_AFTER(state) \
      BOOST_VMD_DETAIL_IS_ALLOW_AFTER(BOOST_VMD_DETAIL_MODS_STATE_ALLOW(state)) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_STATE_IS_ALLOW_INDEX(state) \
      BOOST_VMD_DETAIL_IS_ALLOW_INDEX(BOOST_VMD_DETAIL_MODS_STATE_ALLOW(state)) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_STATE_CURRENT(state) \
      BOOST_PP_TUPLE_ELEM(BOOST_VMD_DETAIL_MODS_STATE_INDEX(state),BOOST_VMD_DETAIL_MODS_STATE_INPUT(state)) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_STATE_TYPE(state) \
      BOOST_PP_TUPLE_ELEM(BOOST_VMD_DETAIL_MODS_TUPLE_RETURN,BOOST_VMD_DETAIL_MODS_STATE_RESULT(state)) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_STATE_AFTER(state) \
      BOOST_PP_TUPLE_ELEM(BOOST_VMD_DETAIL_MODS_TUPLE_AFTER,BOOST_VMD_DETAIL_MODS_STATE_RESULT(state)) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_STATE_ONLY_AFTER(state) \
      BOOST_PP_TUPLE_ELEM(BOOST_VMD_DETAIL_MODS_TUPLE_ONLY_AFTER,BOOST_VMD_DETAIL_MODS_STATE_RESULT(state)) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_STATE_TINDEX(state) \
      BOOST_PP_TUPLE_ELEM(BOOST_VMD_DETAIL_MODS_TUPLE_INDEX,BOOST_VMD_DETAIL_MODS_STATE_RESULT(state)) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_RESULT_RETURN_TYPE(result) \
      BOOST_PP_TUPLE_ELEM(BOOST_VMD_DETAIL_MODS_TUPLE_RETURN,result) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_IS_RESULT_AFTER(result) \
      BOOST_PP_TUPLE_ELEM(BOOST_VMD_DETAIL_MODS_TUPLE_AFTER,result) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_IS_RESULT_ONLY_AFTER(result) \
      BOOST_PP_TUPLE_ELEM(BOOST_VMD_DETAIL_MODS_TUPLE_ONLY_AFTER,result) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_IS_RESULT_INDEX(result) \
      BOOST_PP_TUPLE_ELEM(BOOST_VMD_DETAIL_MODS_TUPLE_INDEX,result) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_RESULT_OTHER(result) \
      BOOST_PP_TUPLE_ELEM(BOOST_VMD_DETAIL_MODS_TUPLE_OTHER,result) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_RESULT_TYPE(result) \
      BOOST_PP_TUPLE_ELEM(BOOST_VMD_DETAIL_MODS_TUPLE_TYPE,result) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_PRED(d,state) \
      BOOST_PP_GREATER_D(d,BOOST_VMD_DETAIL_MODS_STATE_SIZE(state),BOOST_VMD_DETAIL_MODS_STATE_INDEX(state))
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_RETURN_TYPE(d,state,number) \
      BOOST_VMD_DETAIL_MODS_OP_CURRENT_UPDATE \
          ( \
          d, \
          BOOST_PP_TUPLE_REPLACE_D \
              ( \
              d, \
              state, \
              BOOST_VMD_DETAIL_MODS_DATA_RESULT, \
              BOOST_PP_TUPLE_REPLACE_D \
                  ( \
                  d, \
                  BOOST_VMD_DETAIL_MODS_STATE_RESULT(state), \
                  BOOST_VMD_DETAIL_MODS_TUPLE_RETURN, \
                  number \
                  ) \
              ) \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_ONLY_AFTER(d,state,id) \
      BOOST_VMD_DETAIL_MODS_OP_CURRENT_UPDATE \
          ( \
          d, \
          BOOST_PP_TUPLE_REPLACE_D \
              ( \
              d, \
              state, \
              BOOST_VMD_DETAIL_MODS_DATA_RESULT, \
              BOOST_PP_TUPLE_REPLACE_D \
                  ( \
                  d, \
                  BOOST_PP_TUPLE_REPLACE_D \
                      ( \
                      d, \
                      BOOST_VMD_DETAIL_MODS_STATE_RESULT(state), \
                      BOOST_VMD_DETAIL_MODS_TUPLE_ONLY_AFTER, \
                      1 \
                      ), \
                  BOOST_VMD_DETAIL_MODS_TUPLE_AFTER, \
                  1 \
                  ) \
              ) \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_INDEX(d,state,number) \
      BOOST_VMD_DETAIL_MODS_OP_CURRENT_UPDATE \
          ( \
          d, \
          BOOST_PP_TUPLE_REPLACE_D \
              ( \
              d, \
              state, \
              BOOST_VMD_DETAIL_MODS_DATA_RESULT, \
              BOOST_PP_TUPLE_REPLACE_D \
                  ( \
                  d, \
                  BOOST_VMD_DETAIL_MODS_STATE_RESULT(state), \
                  BOOST_VMD_DETAIL_MODS_TUPLE_INDEX, \
                  number \
                  ) \
              ) \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_GTT(d,state,id) \
      BOOST_VMD_DETAIL_MODS_OP_CURRENT_RETURN_TYPE(d,state,BOOST_VMD_DETAIL_MODS_RETURN_TUPLE) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_ET(d,state,id) \
      BOOST_VMD_DETAIL_MODS_OP_CURRENT_RETURN_TYPE(d,state,BOOST_VMD_DETAIL_MODS_RETURN) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_SA(d,state,id) \
      BOOST_VMD_DETAIL_MODS_OP_CURRENT_RETURN_TYPE(d,state,BOOST_VMD_DETAIL_MODS_RETURN_ARRAY) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_SL(d,state,id) \
      BOOST_VMD_DETAIL_MODS_OP_CURRENT_RETURN_TYPE(d,state,BOOST_VMD_DETAIL_MODS_RETURN_LIST) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_NT(d,state,id) \
      BOOST_VMD_DETAIL_MODS_OP_CURRENT_RETURN_TYPE(d,state,BOOST_VMD_DETAIL_MODS_NO_RETURN) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_AFT(d,state,id) \
      BOOST_VMD_DETAIL_MODS_OP_CURRENT_UPDATE \
          ( \
          d, \
          BOOST_PP_TUPLE_REPLACE_D \
              ( \
              d, \
              state, \
              BOOST_VMD_DETAIL_MODS_DATA_RESULT, \
              BOOST_PP_TUPLE_REPLACE_D \
                  ( \
                  d, \
                  BOOST_VMD_DETAIL_MODS_STATE_RESULT(state), \
                  BOOST_VMD_DETAIL_MODS_TUPLE_AFTER, \
                  BOOST_VMD_DETAIL_MODS_RETURN_AFTER \
                  ) \
              ) \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_NOAFT(d,state,id) \
      BOOST_VMD_DETAIL_MODS_OP_CURRENT_UPDATE \
          ( \
          d, \
          BOOST_PP_TUPLE_REPLACE_D \
              ( \
              d, \
              state, \
              BOOST_VMD_DETAIL_MODS_DATA_RESULT, \
              BOOST_PP_TUPLE_REPLACE_D \
                  ( \
                  d, \
                  BOOST_PP_TUPLE_REPLACE_D \
                      ( \
                      d, \
                      BOOST_VMD_DETAIL_MODS_STATE_RESULT(state), \
                      BOOST_VMD_DETAIL_MODS_TUPLE_ONLY_AFTER, \
                      0 \
                      ), \
                  BOOST_VMD_DETAIL_MODS_TUPLE_AFTER, \
                  BOOST_VMD_DETAIL_MODS_NO_AFTER \
                  ) \
              ) \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_IND(d,state,id) \
      BOOST_VMD_DETAIL_MODS_OP_CURRENT_INDEX(d,state,BOOST_VMD_DETAIL_MODS_RETURN_INDEX) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_NO_IND(d,state,id) \
      BOOST_VMD_DETAIL_MODS_OP_CURRENT_INDEX(d,state,BOOST_VMD_DETAIL_MODS_NO_INDEX) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_UNKNOWN_CTUPLE_REPLACE(d,state,id) \
      BOOST_PP_TUPLE_REPLACE_D \
          ( \
          d, \
          BOOST_VMD_DETAIL_MODS_STATE_RESULT(state), \
          BOOST_VMD_DETAIL_MODS_TUPLE_OTHER, \
          BOOST_PP_VARIADIC_TO_TUPLE(id) \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_UNKNOWN_CTUPLE_ADD(d,state,id) \
      BOOST_PP_TUPLE_REPLACE_D \
          ( \
          d, \
          BOOST_VMD_DETAIL_MODS_STATE_RESULT(state), \
          BOOST_VMD_DETAIL_MODS_TUPLE_OTHER, \
          BOOST_PP_TUPLE_PUSH_BACK \
              ( \
              BOOST_VMD_DETAIL_MODS_RESULT_OTHER(BOOST_VMD_DETAIL_MODS_STATE_RESULT(state)), \
              id \
              ) \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_UNKNOWN_CTUPLE(d,state,id) \
      BOOST_PP_IIF \
          ( \
          BOOST_VMD_IS_EMPTY \
              ( \
              BOOST_VMD_DETAIL_MODS_RESULT_OTHER(BOOST_VMD_DETAIL_MODS_STATE_RESULT(state)) \
              ), \
          BOOST_VMD_DETAIL_MODS_OP_CURRENT_UNKNOWN_CTUPLE_REPLACE, \
          BOOST_VMD_DETAIL_MODS_OP_CURRENT_UNKNOWN_CTUPLE_ADD \
          ) \
      (d,state,id) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_UNKNOWN_TYPE_RETURN(d,state,id) \
      BOOST_PP_TUPLE_REPLACE_D \
          ( \
          d, \
          BOOST_VMD_DETAIL_MODS_STATE_RESULT(state), \
          BOOST_VMD_DETAIL_MODS_TUPLE_RETURN, \
          BOOST_PP_IIF \
              ( \
              BOOST_VMD_DETAIL_EQUAL_TYPE_D(d,id,BOOST_VMD_TYPE_ARRAY), \
              BOOST_VMD_DETAIL_MODS_RETURN_ARRAY, \
              BOOST_PP_IIF \
                  ( \
                  BOOST_VMD_DETAIL_EQUAL_TYPE_D(d,id,BOOST_VMD_TYPE_LIST), \
                  BOOST_VMD_DETAIL_MODS_RETURN_LIST, \
                  BOOST_VMD_DETAIL_MODS_RETURN_TUPLE \
                  ) \
              ) \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_UNKNOWN_TYPE(d,state,id) \
      BOOST_PP_TUPLE_REPLACE_D \
          ( \
          d, \
          BOOST_VMD_DETAIL_MODS_OP_CURRENT_UNKNOWN_TYPE_RETURN(d,state,id), \
          BOOST_VMD_DETAIL_MODS_TUPLE_TYPE, \
          id \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_UNKNOWN(d,state,id) \
      BOOST_VMD_DETAIL_MODS_OP_CURRENT_UPDATE \
          ( \
          d, \
          BOOST_PP_TUPLE_REPLACE_D \
              ( \
              d, \
              state, \
              BOOST_VMD_DETAIL_MODS_DATA_RESULT, \
              BOOST_PP_IIF \
                  ( \
                  BOOST_PP_BITAND \
                      ( \
                      BOOST_VMD_DETAIL_MODS_STATE_IS_ALLOW_ALL(state), \
                      BOOST_VMD_IS_TYPE_D(d,id) \
                      ), \
                  BOOST_VMD_DETAIL_MODS_OP_CURRENT_UNKNOWN_TYPE, \
                  BOOST_VMD_DETAIL_MODS_OP_CURRENT_UNKNOWN_CTUPLE \
                  ) \
              (d,state,id) \
              ) \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_UPDATE(d,state) \
      BOOST_PP_TUPLE_REPLACE_D \
          ( \
          d, \
          state, \
          BOOST_VMD_DETAIL_MODS_DATA_INDEX, \
          BOOST_PP_INC(BOOST_VMD_DETAIL_MODS_STATE_INDEX(state)) \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_ALLOW_ALL(d,state,id) \
      BOOST_PP_IIF \
          ( \
          BOOST_VMD_DETAIL_IS_RETURN_TYPE_TUPLE(id), \
          BOOST_VMD_DETAIL_MODS_OP_CURRENT_GTT, \
          BOOST_PP_IIF \
              ( \
              BOOST_VMD_DETAIL_IS_RETURN_TYPE(id), \
              BOOST_VMD_DETAIL_MODS_OP_CURRENT_ET, \
              BOOST_PP_IIF \
                  ( \
                  BOOST_VMD_DETAIL_IS_RETURN_TYPE_ARRAY(id), \
                  BOOST_VMD_DETAIL_MODS_OP_CURRENT_SA, \
                  BOOST_PP_IIF \
                      ( \
                      BOOST_VMD_DETAIL_IS_RETURN_TYPE_LIST(id), \
                      BOOST_VMD_DETAIL_MODS_OP_CURRENT_SL, \
                      BOOST_PP_IIF \
                          ( \
                          BOOST_VMD_DETAIL_IS_RETURN_NO_TYPE(id), \
                          BOOST_VMD_DETAIL_MODS_OP_CURRENT_NT, \
                          BOOST_PP_IIF \
                              ( \
                              BOOST_VMD_DETAIL_IS_RETURN_AFTER(id), \
                              BOOST_VMD_DETAIL_MODS_OP_CURRENT_AFT, \
                              BOOST_PP_IIF \
                                  ( \
                                  BOOST_VMD_DETAIL_IS_RETURN_NO_AFTER(id), \
                                  BOOST_VMD_DETAIL_MODS_OP_CURRENT_NOAFT, \
                                  BOOST_PP_IIF \
                                      ( \
                                      BOOST_VMD_DETAIL_IS_RETURN_ONLY_AFTER(id), \
                                      BOOST_VMD_DETAIL_MODS_OP_CURRENT_ONLY_AFTER, \
                                      BOOST_PP_IIF \
                                          ( \
                                          BOOST_VMD_DETAIL_IS_RETURN_INDEX(id), \
                                          BOOST_VMD_DETAIL_MODS_OP_CURRENT_IND, \
                                          BOOST_PP_IIF \
                                              ( \
                                              BOOST_VMD_DETAIL_IS_RETURN_NO_INDEX(id), \
                                              BOOST_VMD_DETAIL_MODS_OP_CURRENT_NO_IND, \
                                              BOOST_VMD_DETAIL_MODS_OP_CURRENT_UNKNOWN \
                                              ) \
                                          ) \
                                      ) \
                                  ) \
                              ) \
                          ) \
                      ) \
                  ) \
              ) \
          ) \
      (d,state,id) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_ALLOW_RETURN(d,state,id) \
      BOOST_PP_IIF \
          ( \
          BOOST_VMD_DETAIL_IS_RETURN_TYPE_TUPLE(id), \
          BOOST_VMD_DETAIL_MODS_OP_CURRENT_GTT, \
          BOOST_PP_IIF \
              ( \
              BOOST_VMD_DETAIL_IS_RETURN_TYPE(id), \
              BOOST_VMD_DETAIL_MODS_OP_CURRENT_ET, \
              BOOST_PP_IIF \
                  ( \
                  BOOST_VMD_DETAIL_IS_RETURN_TYPE_ARRAY(id), \
                  BOOST_VMD_DETAIL_MODS_OP_CURRENT_SA, \
                  BOOST_PP_IIF \
                      ( \
                      BOOST_VMD_DETAIL_IS_RETURN_TYPE_LIST(id), \
                      BOOST_VMD_DETAIL_MODS_OP_CURRENT_SL, \
                      BOOST_PP_IIF \
                          ( \
                          BOOST_VMD_DETAIL_IS_RETURN_NO_TYPE(id), \
                          BOOST_VMD_DETAIL_MODS_OP_CURRENT_NT, \
                          BOOST_VMD_DETAIL_MODS_OP_CURRENT_UNKNOWN \
                          ) \
                      ) \
                  ) \
              ) \
          ) \
      (d,state,id) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_ALLOW_AFTER(d,state,id) \
      BOOST_PP_IIF \
          ( \
          BOOST_VMD_DETAIL_IS_RETURN_AFTER(id), \
          BOOST_VMD_DETAIL_MODS_OP_CURRENT_AFT, \
          BOOST_PP_IIF \
              ( \
              BOOST_VMD_DETAIL_IS_RETURN_NO_AFTER(id), \
              BOOST_VMD_DETAIL_MODS_OP_CURRENT_NOAFT, \
              BOOST_PP_IIF \
                  ( \
                  BOOST_VMD_DETAIL_IS_RETURN_ONLY_AFTER(id), \
                  BOOST_VMD_DETAIL_MODS_OP_CURRENT_ONLY_AFTER, \
                  BOOST_VMD_DETAIL_MODS_OP_CURRENT_UNKNOWN \
                  ) \
              ) \
          ) \
      (d,state,id) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_ALLOW_INDEX(d,state,id) \
      BOOST_PP_IIF \
          ( \
          BOOST_VMD_DETAIL_IS_RETURN_AFTER(id), \
          BOOST_VMD_DETAIL_MODS_OP_CURRENT_AFT, \
          BOOST_PP_IIF \
              ( \
              BOOST_VMD_DETAIL_IS_RETURN_NO_AFTER(id), \
              BOOST_VMD_DETAIL_MODS_OP_CURRENT_NOAFT, \
              BOOST_PP_IIF \
                  ( \
                  BOOST_VMD_DETAIL_IS_RETURN_ONLY_AFTER(id), \
                  BOOST_VMD_DETAIL_MODS_OP_CURRENT_ONLY_AFTER, \
                  BOOST_PP_IIF \
                      ( \
                      BOOST_VMD_DETAIL_IS_RETURN_INDEX(id), \
                      BOOST_VMD_DETAIL_MODS_OP_CURRENT_IND, \
                      BOOST_PP_IIF \
                          ( \
                          BOOST_VMD_DETAIL_IS_RETURN_NO_INDEX(id), \
                          BOOST_VMD_DETAIL_MODS_OP_CURRENT_NO_IND, \
                          BOOST_VMD_DETAIL_MODS_OP_CURRENT_UNKNOWN \
                          ) \
                      ) \
                  ) \
              ) \
          ) \
      (d,state,id) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_ALLOW_UPDATE(d,state,id) \
      BOOST_VMD_DETAIL_MODS_OP_CURRENT_UPDATE(d,state) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_ID(d,state,id) \
      BOOST_PP_IIF \
          ( \
          BOOST_VMD_DETAIL_MODS_STATE_IS_ALLOW_ALL(state), \
          BOOST_VMD_DETAIL_MODS_OP_CURRENT_ALLOW_ALL, \
          BOOST_PP_IIF \
              ( \
              BOOST_VMD_DETAIL_MODS_STATE_IS_ALLOW_RETURN(state), \
              BOOST_VMD_DETAIL_MODS_OP_CURRENT_ALLOW_RETURN, \
              BOOST_PP_IIF \
                  ( \
                  BOOST_VMD_DETAIL_MODS_STATE_IS_ALLOW_AFTER(state), \
                  BOOST_VMD_DETAIL_MODS_OP_CURRENT_ALLOW_AFTER, \
                  BOOST_PP_IIF \
                      ( \
                      BOOST_VMD_DETAIL_MODS_STATE_IS_ALLOW_INDEX(state), \
                      BOOST_VMD_DETAIL_MODS_OP_CURRENT_ALLOW_INDEX, \
                      BOOST_VMD_DETAIL_MODS_OP_CURRENT_ALLOW_UPDATE \
                      ) \
                  ) \
              ) \
          ) \
      (d,state,id) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT_TUPLE(d,state,id) \
      BOOST_VMD_DETAIL_MODS_OP_CURRENT_UPDATE \
          ( \
          d, \
          BOOST_PP_TUPLE_REPLACE_D \
              ( \
              d, \
              state, \
              BOOST_VMD_DETAIL_MODS_DATA_RESULT, \
              BOOST_PP_TUPLE_REPLACE_D \
                  ( \
                  d, \
                  BOOST_VMD_DETAIL_MODS_STATE_RESULT(state), \
                  BOOST_VMD_DETAIL_MODS_TUPLE_OTHER, \
                  id \
                  ) \
              ) \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP_CURRENT(d,state,id) \
      BOOST_PP_IIF \
          ( \
          BOOST_PP_IS_BEGIN_PARENS(id), \
          BOOST_VMD_DETAIL_MODS_OP_CURRENT_TUPLE, \
          BOOST_VMD_DETAIL_MODS_OP_CURRENT_ID \
          ) \
      (d,state,id) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_OP(d,state) \
      BOOST_VMD_DETAIL_MODS_OP_CURRENT(d,state,BOOST_VMD_DETAIL_MODS_STATE_CURRENT(state)) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_LOOP(allow,tuple) \
      BOOST_PP_TUPLE_ELEM \
          ( \
          3, \
          BOOST_PP_WHILE \
              ( \
              BOOST_VMD_DETAIL_MODS_PRED, \
              BOOST_VMD_DETAIL_MODS_OP, \
                  ( \
                  tuple, \
                  0, \
                  BOOST_PP_TUPLE_SIZE(tuple), \
                  (0,0,0,,0,), \
                  allow \
                  ) \
              ) \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_MODS_LOOP_D(d,allow,tuple) \
      BOOST_PP_TUPLE_ELEM \
          ( \
          3, \
          BOOST_PP_WHILE_ ## d \
              ( \
              BOOST_VMD_DETAIL_MODS_PRED, \
              BOOST_VMD_DETAIL_MODS_OP, \
                  ( \
                  tuple, \
                  0, \
                  BOOST_PP_TUPLE_SIZE(tuple), \
                  (0,0,0,,0,), \
                  allow \
                  ) \
              ) \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_NEW_MODS_VAR(allow,tuple) \
      BOOST_VMD_DETAIL_MODS_LOOP \
          ( \
          allow, \
          BOOST_PP_TUPLE_POP_FRONT(tuple) \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_NEW_MODS_VAR_D(d,allow,tuple) \
      BOOST_VMD_DETAIL_MODS_LOOP_D \
          ( \
          d, \
          allow, \
          BOOST_PP_TUPLE_POP_FRONT(tuple) \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_NEW_MODS_IR(allow,tuple) \
      BOOST_VMD_IDENTITY_RESULT \
          ( \
          BOOST_PP_IIF \
              ( \
              BOOST_PP_EQUAL(BOOST_PP_TUPLE_SIZE(tuple),1), \
              BOOST_VMD_IDENTITY((0,0,0,,0,)), \
              BOOST_VMD_DETAIL_NEW_MODS_VAR \
              ) \
          (allow,tuple) \
          ) \
  /**/
  
  #define BOOST_VMD_DETAIL_NEW_MODS_IR_D(d,allow,tuple) \
      BOOST_VMD_IDENTITY_RESULT \
          ( \
          BOOST_PP_IIF \
              ( \
              BOOST_PP_EQUAL_D(d,BOOST_PP_TUPLE_SIZE(tuple),1), \
              BOOST_VMD_IDENTITY((0,0,0,,0,)), \
              BOOST_VMD_DETAIL_NEW_MODS_VAR_D \
              ) \
          (d,allow,tuple) \
          ) \
  /**/
  
  /*
  
    Returns a six-element tuple:
  
    First tuple element  = 0 No type return
                           1 Exact type return
                           2 General tuple type return
                           3 Array return
                           4 List return
  
    Second tuple element = 0 No after return
                           1 After return
  
    Third tuple element  = 0 No identifier index
                           1 Identifier Index
  
    Fourth tuple element = Tuple of other identifiers
  
    Fifth tuple element  = 0 No after only return
                           1 After only return
  
    Sixth tuple element  = Type identifier
  
    Input                = allow, either
                           BOOST_VMD_ALLOW_ALL
                           BOOST_VMD_ALLOW_RETURN
                           BOOST_VMD_ALLOW_AFTER
                           BOOST_VMD_ALLOW_INDEX
  
                             ..., modifiers, first variadic is discarded
                           Possible modifiers are:
  
                           BOOST_VMD_RETURN_NO_TYPE = (0,0)
                           BOOST_VMD_RETURN_TYPE = (1,0)
                           BOOST_VMD_RETURN_TYPE_TUPLE = (2,0)
                           BOOST_VMD_RETURN_TYPE_ARRAY = (3,0)
                           BOOST_VMD_RETURN_TYPE_LIST = (4,0)
  
                           BOOST_VMD_RETURN_NO_AFTER = (0,0)
                           BOOST_VMD_RETURN_AFTER = (0,1)
  
  */
  
  #define BOOST_VMD_DETAIL_NEW_MODS(allow,...) \
      BOOST_VMD_DETAIL_NEW_MODS_IR(allow,BOOST_PP_VARIADIC_TO_TUPLE(__VA_ARGS__)) \
  /**/
  
  #define BOOST_VMD_DETAIL_NEW_MODS_D(d,allow,...) \
      BOOST_VMD_DETAIL_NEW_MODS_IR_D(d,allow,BOOST_PP_VARIADIC_TO_TUPLE(__VA_ARGS__)) \
  /**/
  
  #endif /* BOOST_VMD_DETAIL_MODS_HPP */
  