Add TODOs

TODO.md

@@ -9,10 +9,11 @@ Related TODO files:
 
 ## Next
 
+- Observe an array or nested arrays for all children changes on a specific property (e.g. observe(@game, 'tetris_blocks[][].color') ; returns |new_color, tetris_block| / observe(@game.players, '[].name') ; returns |name, player|)
+- Observe multiple attributes (e.g. observe(@game, [:width, :height]) returns |value, attribute_name|)
 - Fix issue with computed data-binding when combined with nested/indexed data-binding (it looks up computed attributes on root object instead of nested object, it seems)
 - Support nested computed attributes (e.g. computed_by: {address1: [:street, :city, :state, :zip]})
 - Consider the idea of having Observer#observe accept an optional block to do observation without implementing `call` (kinda like when using the `observe` keyword in the Glimmer DSL). 
-- Observe an array for all children changes on a specific property (e.g. observe(@game, 'blocks[][].color') ; returns |new_color, block|)
 - Ensure removing observers from hash in ObservableModel when removed from observable
 - Avoid `< Struct.new` in specs (tests)
 - Add built-in support to Glimmer::DSL::Engine to memoize/cache expressions similar to how that is supported for StaticExpression (but allowing an outside keyword and non-static expression to be used)

lib/glimmer/data_binding/model_binding.rb

@@ -131,6 +131,8 @@ def nested_property_observers_for(observer)
       end
 
       def add_observer(observer, extra_options = {})
+        # TODO couldn't we have a scenario where it is both computed? and nested_property? at the same time?
+        # or computed and not nested at the same time (else statement)?
         if computed?
           add_computed_observers(observer)
         elsif nested_property?