Added Data and Extern Type notes.

Removed Merge Interfaces.

TODO.md

@@ -8,10 +8,6 @@ Private/Public
 --------------
 Declaring sections as Private should prevent generation to the interface (.i)
 
-Merge Interfaces
-----------------
-Modules that require multiple files need to merge the imported interfaces into the main interface, visible as its public API.
-
 OpenGL/EGL
 ----------
 See what needs to be done to port GL to EGL (for such platforms as the RPi)
@@ -37,3 +33,24 @@ Framework
 ---------
 When compiling an application with a "Framework", the framework chosen is passed down to all the imported source files and applied to them too. Without it, each imported source is assumed to have access to *all* the standard modules (and will include all of them in their interface).
 Currently not supporting an application build without framework...
+
+Data
+----
+DefData, ReadData and RestoreData and data labels (#) are not currently implemented.
+
+See blitz_types.h for tag types.
+Data is stored thus :
+  data type
+  data
+  data type
+  data
+  ...
+An index/pointer will need to keep track of the current position in the data.
+RestoreData can reset this to a 'data label' position.
+
+Extern Types
+------------
+Represents a C structure directly in the code.
+
+Does not support internal methods/functions.
+We may be able to simply create a struct here that we can pass to functions, etc.