@ridgeworks Thank you so much for the extensive and interesting response !
Well, I’m more trying to learn new things through these experiments.
For example, while writing these grammars, I’ve learned that:
- you can use tail call optimize predicates to split your grammar into smaller logical parts
- I have learned the subtil difference between the different reification operators in clpfd like
#<==>and#<== - I have learned that there is 3 order of magnitude difference between the speed of raw prolog arithmetic and clp pure arithmetic
It’s also because everybody says that you should not do this kind of things ^^
Some write poetry, I prefer this kind of writing 
I think @jan called it a mild case of stockholm syndrom 