anchor.diff:  % export helper functions
   % ==============================================================================
   
  +% Format a link for jiffy.  "system" links are ignored.
   json_link(#identifier{metadata = #{system := _}}) ->
       % do not save system identifiers
       [];
  
positive.code:             ]}} | Acc]
          end, [], Metadata).
  
  json_metadata(true) ->
      true;
  json_metadata(false) ->
  
negative.code:                 [{Key, json_metadata(Value)} | Acc]
              end, [], Data)
      }.
  
  % ==============================================================================
  % import helper functions
  