Hi, at the recent BachoTeX conference, I held a talk comparing LuaTeX and LilyPond integration of their respective extension languages. Now the talk slot was just 30 minutes, so the talk was quite more condensed than the proceedings, and I probably would have had to take the laptop away from Hans to have the talk make much of an impression anyway (not that there would have been much of a talk if people had locked _my_ laptop away in the days before it) and that still would not have given me a hook into Taco who had to miss out on BachoTeX because of anniversative conditions. So I am instead dumping the PDF of the proceedings on this list as it may inspire people to try working on some more user-manageable low-level interaction between Lua and TeX than the current situation provides. I've added some rough sketches at the end of the article that should make clear why this can't be done in formats alone but will require primitive support as well if things are supposed to turn out nicely. Hope you can make something of it. -- David Kastrup