Inital consideration for regular data structure enumaration

I think we may do this topic in a step by step way:

In the first step, we still persist to static type, we only use regular expression to enumerate to a certain sub constructor with known name, the compiler will try to figure out the actual and complete sub constructor enumerate process.
The goal of this idea is just to separate the data structure from program structure. Even if the library developer change the data structure significantly, we can still compile the old code.