anchor.diff:      end.
   
   get_group(Name, Commit) ->
  -    wallaroo ! {get, group, Name, canonicalize_hash(Commit)}.
  +    gen_server:call(wallaroo,  {get, group, Name, canonicalize_hash(Commit)}).
   
   get_tag(Name) ->
  -    wallaroo ! {get_tag, Name}.
  +    gen_server:call(wallaroo,  {get_tag, Name}).
   
   put_tag(Name, C) ->
       Commit = canonicalize_hash(C),
  -    wallaroo ! {put_tag, Name, Commit}.
  +    gen_server:call(wallaroo,  {put_tag, Name, Commit}).
   
   put_group(Name, {wallaby_group, [_|_]}=Group) ->
  -    wallaroo ! {put, group, Name, Group}.
  +    gen_server:call(wallaroo,  {put, group, Name, Group}).
   
   put_node(Name, {wallaby_node, [_|_]}=Node) ->
  -    wallaroo ! {put, node, Name, Node}.
  +    gen_server:call(wallaroo,  {put, node, Name, Node}).
   
   put_group(Name, {wallaby_group, [_|_]}=Group, SC) ->
       C = canonicalize_hash(SC),
  -    wallaroo ! {put, group, Name, Group, C}.
  +    gen_server:call(wallaroo,  {put, group, Name, Group, C}).
   
   put_node(Name, {wallaby_node, [_|_]}=Node, SC) ->
       C = canonicalize_hash(SC),
  -    wallaroo ! {put, node, Name, Node, C}.
  +    gen_server:call(wallaroo,  {put, node, Name, Node, C}).
   
   
   %%% gen_server callbacks
  
positive.code: -define(SERVER, ?MODULE).
  
  start_link() ->
      wallaroo_store_ets:init(),
      gen_server:start_link(?MODULE, [], []).
  
  init([]) ->
      {ok, {wallaroo_store_ets}}.
  
negative.code:     end.
  
  get_node(Name, Commit) ->
      gen_server:call(wallaroo,  {get, node, Name, canonicalize_hash(Commit)}).
  
  get_group(Name) ->
      case get_tag("current") of
  