anchor.diff:  
   render_attr_value(Val) when is_float(Val) ->
       io_lib:format("~p", [Val]);
  -render_attr_value(Val) when is_integer(Val) ->
  -    io_lib:format("~p", [Val]);
   render_attr_value(#uri{}=Val) ->
       occi_uri:to_string(Val);
   render_attr_value(Val) ->
       Val.
   
  -make_doc(DeclaredNS, NS, Name, Attrs, Children) ->
  -    make_ns(DeclaredNS, exmpp_xml:element(NS, Name, Attrs, Children)).
  -
   make_ns([], #xmlel{}=E) ->
       E;
   make_ns([{NS, Prefix}|Tail], #xmlel{}=E) ->
  
positive.code: 		make_attribute('occi.core.target', occi_link:get_target(Link))],
      Children2 = case occi_link:get_source(Link) of
  		    undefined -> Children;
  		    #uri{}=Uri ->
  			make_attribute('occi.core.source', Uri)
  		end,
      E = make_doc([?declared_occi_ns, ?declared_xlink_ns],
  		 ?occi_ns, link,
  		 [exmpp_xml:attribute(<<"id">>, occi_uri:to_string(occi_link:get_id(Link))),
  		  exmpp_xml:attribute(<<"title">>, occi_link:get_title(Link))],
  		 Children2),
      sets:fold(
        fun (Mixin, Acc) -> render_cid(Acc, mixin, Mixin) end, 
        lists:foldl(
  	fun (Attr, Acc) -> render_attribute(Acc, Attr) end,
  	E,
  	occi_link:get_attributes(Link)), 
        occi_link:get_mixins(Link)).
  
  make_dir(#occi_node{id=Id, type=dir, data=Children}) ->
      exmpp_xml:element(?occi_ns, collection, 
  
negative.code:     {[Data, "\n"], Env};
  
  render(#occi_node{type=occi_resource, data=Res}, Env) ->
      E = make_ns([?declared_occi_ns, ?declared_xlink_ns],
  		exmpp_xml:element(
  		  ?occi_ns, resource,
  		  [exmpp_xml:attribute(<<"id">>, occi_uri:to_binary(occi_resource:get_id(Res))),
  		   exmpp_xml:attribute(<<"title">>, occi_resource:get_title(Res))], 
  		  [make_cid(kind, occi_resource:get_cid(Res))])),
      Data = render_xml(
  	     lists:foldl(
  	       fun (#uri{}=Link, Acc) -> 
  