The harder think to handle is Expression and have take me long time to find how do it.
But, at the end, I have code it. So theoricaly my code is complete. But practicaly, I have to do unit test and full test to check all and find all little bug hide in code.
It will take a lot if time to write unite test for all but it is needed to have a really good code.
I have discover a lot of things with it, for moment. Especially, that lexer/parser design pattern is really great to read any file with grammar. In futur, I will use it for any EDI file or XML file. For flat file with quote delimiter or fixed lenght encodin, it is not good but for any file with grammar, hierarchical structure it is the best to have a complete system easy to read.