anchor.diff:  -type path() :: {Start::pos_integer(), branch()}.
   -type tree() :: [branch()]. % sorted by key
   
  --record(rev_info,
  -    {
  +-record(rev_info, {
       rev,
       seq = 0,
       deleted = false,
       body_sp = nil % stream pointer
  -    }).
  -
  --record(doc_info,
  -    {
  +}).
  +
  +-record(doc_info, {
       id = <<"">>,
       high_seq = 0,
       revs = [] % rev_info
  -    }).
  -
  --record(full_doc_info,
  -    {id = <<"">>,
  +}).
  +
  +-record(full_doc_info, {
  +    id = <<"">>,
       update_seq = 0,
       deleted = false,
       rev_tree = [],
       leafs_size = 0
  -    }).
  -
  --record(httpd,
  -    {mochi_req,
  +}).
  +
  +-record(httpd, {
  +    mochi_req,
       peer,
       method,
       requested_path_parts,
  
positive.code:     % key/value tuple of meta information, provided when using special options:
      % couch_db:open_doc(Db, Id, Options).
      meta = []
      }).
  
  
  -record(att,
      {
      name,
      type,
      att_len,
  
negative.code:     auth,
      default_fun,
      url_handlers
  }).
  
  
  -record(doc, {
      id = <<"">>,
      revs = {0, []},
  
  