Update TODO.md for Workflow to C++ code generation

Import/TODO.md

@@ -1,14 +1,15 @@
 # TODO
 
 * Workflow
-    * Enum
-    * Struct
-    * Expression: new T{x}, Enum.Item
-    * async, delay, yield (provider written in C++)
-    * Workflow to C++ code generation with hint
-        * Only `Enumerable<T>^` and `ObservableList^` are allowed in script
-        * All native classes report real C++ collection type when using collection objects
-        * Only `TypedValueSerializerProvider<T>` instances support serialization (e.g. `Color`)
+    * Enum, `(Item1 | Item2 | Item3)::Enum`, giving a type is not always necessary.
+    * Struct, `{fontFamily:'Segoe UI', size:10}::FontProperties`, giving a type is not always necessary.
+    * async, delay, yield (provider written in C++). **low priority**
+    * Limited serialization
+        * Disable serialization for struct and enum.
+        * Only `TypedValueSerializerProvider<T>` instances support serialization (e.g. `Color`), or provide a global type conversion interface and registration for type. Only the type author of T can provide all convensions from T to U.
+    * Workflow to C++ code generation with hint.
+        * Only `Enumerable<T>^` and `ObservableList^` are allowed in script.
+        * All native classes report real C++ collection type when using collection objects.
         * C++ code generator reports errors when any script does not satisfy these rules
 * GacUI Resource
     * InheritableCustomWindow
@@ -20,6 +21,9 @@
     * Pure C++ Code Generation
     * Visual State, State Machine, Animation
     * ev.Event-(eval|async|delayed)
+    * Special grammar kicks in when assigning a text literal to non-serializable struct or enum types
+        * enum: `Item1 | Item2 | Item2`, the same as previous.
+        * struct: `fontFamily:'Segoe UI' size:10`, the same as previous, but no more {} escaping.
 * Core
     * Make ItemSource from constructor argument to property
     * Embedded Languages: Colorizer, AutoComplete