undefined vs []

src/render/wf_render.erl

@@ -5,17 +5,11 @@
 render_item([]) -> <<>>;
 render_item(undefined) -> <<>>;
 render_item(E) when element(2,E) =:= element -> wf_render_elements:render_element(E);
-render_item(E) when element(2,E) =:= action  ->
-%    io:format("Render Action: ~p~n",[E]),
-    wf_render_actions:render_action(E);
-render_item(E) ->
-%    io:format("Render Item: ~p~n",[E]),
-    E.
+render_item(E) when element(2,E) =:= action  -> wf_render_actions:render_action(E);
+render_item(E) -> E.
 
 render([]) -> <<>>;
 render(undefined) -> <<>>;
 render(<<E/binary>>) -> E;
-render(Elements) when is_list(Elements) ->
-%    io:format("Render: ~p~n",[Elements]),
-   [ render_item(E) || E <- Elements, E /= undefined ];
+render(Elements) when is_list(Elements) -> [ render_item(E) || E <- Elements, E /= undefined ];
 render(Elements) -> render_item(Elements).

src/render/wf_tags.erl

@@ -12,6 +12,8 @@
 
 emit_tag(TagName, Props) -> [<<"<">>,TagName] ++ write_props(Props) ++ [<<"/>">>].
 emit_tag(TagName, undefined, Props) -> emit_tag(TagName, [], Props);
+emit_tag(TagName, [], Props) -> emit_tag(TagName, [], Props);
+emit_tag(TagName, [[]], Props) -> emit_tag(TagName, [], Props);
 emit_tag(TagName, [undefined], Props) -> emit_tag(TagName, [], Props);
 emit_tag(TagName, <<>>, Props) when ?VOID(TagName) -> emit_tag(TagName, Props);
 emit_tag(TagName, [], Props) -> [<<"<">>,TagName,write_props(Props),<<">">>,<<"</">>,TagName,<<">">>];