Refining of current framework

1. Using pairs like (CAS, AA) to describe AAF, AF, & AInst, so:
AAF(CAS, AA); AF(CAS, AA); AInst(CAS, AA)

2. SPL
Functional variations: types in AAF, subtypes in AAF
Parameters: from AAF to AF by user interaction
Platform variations: from AF to AInst by using Semantic Interpreters

3. Think about the storing structure of different feature of the framework
The structure of AAF/AF/AInst is a typical tree, the best way to save a tree to database is?