@nasser Did you see F'Santanna's latest project?
"Atmos is a programming library for Lua that reconciles Structured Concurrency with Event-Driven Programming"
https://github.com/lua-atmos/atmos/tree/main
Don't know if there's anything conceptually new in there compared to Céu, but I know I'm going to have an easier time reading an in-Lua library for Lua, than trying to grok a compiler implemented in Lua for compiling a different language to a finite state machine in C.