anchor.diff:  tag_to_value($B, _, _, _Options) ->
      ""; % NotImplementedError
   
  +%% Only show era (BCE/CE) when date is BCE
  +tag_to_value($e, {Y, _, _} = Date, Time, Options) when Y < 0 ->
  +   tag_to_value($E, Date, Time, Options);
  +tag_to_value($e, _, _, _Options) ->
  +   "";
  +
  +%% Always show era (BCE/CE)
  +tag_to_value($E, {Y, _, _}, _, Options) when Y < 0 ->
  +    tr(label, bce, Options);
  +tag_to_value($E, _, _, Options) ->
  +    tr(label, ce, Options);
  +
   %
   % Time, in 12-hour hours and minutes, with minutes
   % left off if they're zero.
  
positive.code: %% @doc Provide some english date strings
  tr(label, midnight) -> "midnight";
  tr(label, noon) -> "noon";
  
  %% @doc Provide english versions of the day of the week.
  tr(dayname, 1) -> "Monday";
  
negative.code:     C =:= $c orelse
      C =:= $d orelse
      C =:= $D orelse
      C =:= $e orelse
      C =:= $E orelse
      C =:= $f orelse
      C =:= $F orelse
      C =:= $g orelse
  