[Plan] Enhancement for parsing and rewriting modules of Sharding-Core

[juan pan <pa...@apache.org>]

To make Sharding-Core stable and reliable, it is necessary to go through
current parsing and rewriting modules of Sharding-Core.

Here are main tasks:

   1. Consider consistent values and names e.g. StartIndex, StopIndex to
   define token index for rewriting
   2. Sort out all of the segments, and consider to define tokenSegment
   3. Instead of original literals, use StartIndex, StopIndex to rewrite
   SQL.
   4. Review all of tokens, plese specially notice IndexToken
   5. Consider whether statements could be made of segments and tokens.

What is your opinion? Welcome to see your reply.

---------------------------------
Juan Pan (Trista)
Apache ShardingSphere