anchor.diff:      RT;
   
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  -% signedIntegerLiteral
  -%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  -
  -fold(FType, Fun, Ctx, Lvl, {signedIntegerLiteral, {decimalInteger, _} = DecimalInteger} = ST) ->
  -    ?debugFmt("wwe debugging fold/5 ===> Start ~p~n ST: ~p~n", [Lvl, ST]),
  -    NewCtx = case FType of
  -                 top_down -> Fun(ST, Ctx);
  -                 bottom_up -> Ctx
  -             end,
  -    {DecimalIntegerNew, NewCtx1} = fold(FType, Fun, NewCtx, Lvl + 1, DecimalInteger),
  -    NewCtx2 = case FType of
  -                  top_down -> NewCtx1;
  -                  bottom_up -> Fun(ST, NewCtx1)
  -              end,
  -    RT = {DecimalIntegerNew, NewCtx2},
  -    ?debugFmt("wwe debugging fold/5 ===> ~n RT: ~p~n", [RT]),
  -    RT;
  -
  -%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   % Statement
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   
  
positive.code: % Terminals.
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  fold(FType, Fun, Ctx, _Lvl, {decimalInteger, {"-" = Sign, {unsignedDecimalInteger, UnsignedDecimalInteger}}} = ST) ->
      ?debugFmt("wwe debugging fold/5 ===> Start ~p~n ST: ~p~n", [_Lvl, ST]),
      NewCtx = case FType of
                   top_down -> Fun(ST, Ctx);
                   bottom_up -> Ctx
               end,
      NewCtx1 = case FType of
                    top_down -> NewCtx;
                    bottom_up -> Fun(ST, NewCtx)
                end,
      RT = {Sign ++ UnsignedDecimalInteger, NewCtx1},
      ?debugFmt("wwe debugging fold/5 ===> ~n RT: ~p~n", [RT]),
      RT;
  fold(FType, Fun, Ctx, _Lvl, {decimalInteger, {unsignedDecimalInteger, UnsignedDecimalInteger}} = ST) ->
      ?debugFmt("wwe debugging fold/5 ===> Start ~p~n ST: ~p~n", [_Lvl, ST]),
      NewCtx = case FType of
                   top_down -> Fun(ST, Ctx);
                   bottom_up -> Ctx
               end,
      NewCtx1 = case FType of
                    top_down -> NewCtx;
                    bottom_up -> Fun(ST, NewCtx)
                end,
      RT = {UnsignedDecimalInteger, NewCtx1},
      ?debugFmt("wwe debugging fold/5 ===> ~n RT: ~p~n", [RT]),
      RT;
  fold(FType, Fun, Ctx, _Lvl, {doubleLiteral, {DoubleType, Double}} = ST)
      when DoubleType == exponentDecimalReal; DoubleType == regularDecimalReal ->
      ?debugFmt("wwe debugging fold/5 ===> Start ~p~n ST: ~p~n", [_Lvl, ST]),
  
negative.code:     RT = {lists:flatten(StatementNew), NewCtx2},
      ?debugFmt("wwe debugging fold/5 ===> ~n RT: ~p~n", [RT]),
      RT;
  
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  % expression2
  