anchor.diff:                          [], M);
            error -> []
        end,
  -     "\r\n",V].
  +     "\r\n",encode_value(V)].
   
   
   %% @spec select_doc(context()) -> {metadata(), value()}|multiple_choices
  
positive.code:     case DocCtx#ctx.doc of
          {ok, _} ->
              case select_doc(DocCtx) of
                  {MD, _} ->
                      {[{dict:fetch(?MD_CTYPE, MD), produce_doc_body}], RD, DocCtx};
                  multiple_choices ->
                      {[{"text/plain", produce_sibling_message_body},
                        {"multipart/mixed", produce_multipart_body}], RD, DocCtx}
  
negative.code:                                   {ok, Ls} -> Ls;
                                    error -> []
                                end]])),
      [?HEAD_CTYPE, ": ",get_ctype(MD,V),
       case dict:find(?MD_CHARSET, MD) of
           {ok, CS} -> ["; charset=",CS];
           error -> []
  