anchor.diff:      db,
       limit,
       include_docs,
  +    doc_info = nil,
       offset = nil,
       total_rows,
       reduce_fun = fun couch_db:enum_docs_reduce_to_count/1,
  
positive.code:         % we'll embed this at a higher level b/c the doc may be non-local
          Doc = undefined;
      IncludeDocs ->
          case couch_db:open_doc(Db, Id, []) of
          {not_found, deleted} ->
              Doc = null;
          {not_found, missing} ->
  
negative.code: view_fold(#full_doc_info{} = FullDocInfo, OffsetReds, Acc) ->
      % matches for _all_docs and translates #full_doc_info{} -> KV pair
      case couch_doc:to_doc_info(FullDocInfo) of
      #doc_info{id=Id, revs=[#rev_info{deleted=false, rev=Rev}|_]} = DI ->
          Value = {[{rev,couch_doc:rev_to_str(Rev)}]},
          view_fold({{Id,Id}, Value}, OffsetReds, Acc#view_acc{doc_info=DI});
      #doc_info{revs=[#rev_info{deleted=true}|_]} ->
          {ok, Acc}
      end;
  