filter_spirit VS spirit

While I do like projects like this in this case I think I like the way filter spirit solved it more. I can do something like:

This looks like a great collection of ideas, many of which I have already implemented in my own filter-generating tool (which compared to yours is more advanced on the internal feature side but has basic CLI + terrible UI). I think we could collaborate to create something together (I could already mention many possible features - poe.ninja-based generation, filter template description language, color/strictness presets). I have large amounts of notes from working with filters (many not published on my github project).

You might be interested in https://github.com/Xeverous/filter_spirit/blob/master/doc/user/actual_filter_quirks.md

Oh, one project that I learned a lot of modern C++ from was, https://github.com/boostorg/spirit, I wanted to build a faster org-mode parser. I built at best a working prototype, but ended up learning a lot about how templates. It is also a header only library. If you want to avoid some administrative work, linking, choosing a build system, .... I figured it might be helpful.

Sadly, this still includes the to me [rather critical bug in Boost Spirit](https://github.com/boostorg/spirit/issues/688). I was hoping that a patch would come through before release.

People behind https://github.com/boostorg/spirit who helped in fixing numerous issues regarding newest library edition and helped track down a GCC bug. Boost Spirit LL(∞) parser is the core of this project.