anchor.diff:  
   
   get_path(What, Name, Tree, StoreMod) ->
  -    Path = [What ++ "s", Name],
  +    Path = [atom_to_list(What) ++ "s", Name],
       wallaroo_tree:get_path(Path, Tree, StoreMod).
   
  -put_path(What, Name, Value, Tree, StoreMod) ->
  -    Path = [What ++ "s", Name],
  -    wallaroo_tree:put_path(Path, Value, Tree, StoreMod).
  +put_path(What, Name, Value, Tree, StoreMod, empty) ->
  +    Commit = wallaroo_commit:store(wallaroo_commit:empty(), StoreMod),
  +    put_path(What, Name, Value, Tree, StoreMod, Commit);
  +put_path(What, Name, Value, Tree, StoreMod, ParentCommit) ->
  +    Path = [atom_to_list(What) ++ "s", Name],
  +    {NewTree, _} = wallaroo_tree:put_path(Path, Value, Tree, StoreMod),
  +    Commit = wallaroo_commit:new([ParentCommit], NewTree, [], []),
  +    wallaroo_commit:store(Commit, StoreMod).
   
   get_commit(SHA, StoreMod) ->
  -    StoreMod:find_commit(SHA).
  +    Result = StoreMod:find_commit(SHA),
  +    error_logger:info_msg("wallaroo:get_commit/2 -> ~p ~n", [Result]),
  +    Result.
   
  
positive.code:     end.
  
  get_group(Name, Commit) ->
      wallaroo ! {get, group, Name, canonicalize_hash(Commit)}.
  
  get_tag(Name) ->
      wallaroo ! {get_tag, Name}.
  
  put_tag(Name, C) ->
      Commit = canonicalize_hash(C),
      wallaroo ! {put_tag, Name, Commit}.
  
  put_group(Name, {wallaby_group, [_|_]}=Group) ->
      wallaroo ! {put, group, Name, Group}.
  
  put_node(Name, {wallaby_node, [_|_]}=Node) ->
      wallaroo ! {put, node, Name, Node}.
  
  put_group(Name, {wallaby_group, [_|_]}=Group, SC) ->
      C = canonicalize_hash(SC),
      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 callbacks
  
negative.code: -define(SERVER, ?MODULE).
  
  start_link() ->
      error_logger:info_msg("entering WALLAROO start_link/0 ~n", []),
      wallaroo_store_ets:init([]),
      Result = try 
  		 gen_server:start_link({local, ?SERVER}, ?MODULE, [], [])
  	     catch
  		 Kind:Reason -> error_logger:info_msg("failure! ~p:~p~n", [Kind, Reason]), {failure_with, {Kind, Reason}}
  	     end,
      error_logger:info_msg("returning ~p from WALLAROO start_link/0 ~n", [Result]),
      Result.
  
  init([]) ->
      {ok, {wallaroo_store_ets}}.
  