anchor.diff:  				F(mnesia:select(offer, MatchSpec,
   						?CHUNKSIZE, read), Acc);
   			F('$end_of_table', Acc) ->
  -				Acc;
  +				{ok, Acc};
   			F({error, Reason}, _Acc) ->
   				{error, Reason};
   			F({L, Cont}, Acc) ->
   				F(mnesia:select(Cont), [L | Acc])
   	end,
  -	case mnesia:ets(F, [F, start, []]) of
  +	case mnesia:ets(F, [start, []]) of
   		{error, Reason} ->
   			{error, Reason};
   		{ok, Acc} when is_list(Acc) ->
  
positive.code: 				F(mnesia:select(resource, MatchSpec,
  						?CHUNKSIZE, read), Acc);
  			F('$end_of_table', Acc) ->
  				Acc;
  			F({error, Reason}, _Acc) ->
  				{error, Reason};
  			F({L, Cont}, Acc) ->
  				F(mnesia:select(Cont), [L | Acc])
  	end,
  	case mnesia:ets(F, [F, start, []]) of
  		{error, Reason} ->
  			{error, Reason};
  		{ok, Acc} when is_list(Acc) ->
  
negative.code: 				F(mnesia:select(product, MatchSpec,
  						?CHUNKSIZE, read), Acc);
  			F('$end_of_table', Acc) ->
  				{ok, Acc};
  			F({error, Reason}, _Acc) ->
  				{error, Reason};
  			F({L, Cont}, Acc) ->
  				F(mnesia:select(Cont), [L | Acc])
  	end,
  	case mnesia:ets(F, [start, []]) of
  		{error, Reason} ->
  			{error, Reason};
  		{ok, Acc} when is_list(Acc) ->
  