I think the description is not sufficient to disambiguate data packs using mcfunctions (there are multiple compilers targeting this, e.g. [1]) from data packs just using command blocks. Langcraft turns out to be the latter. LLVM IR to mcfunction compiler would be also interesting :-)

[1] https://github.com/Stevertus/mcscript

I'm not sure if I'd call the latter much of a "datapack" in the first place ;p because while yes, technically it is, I don't think it's that much of an improvement over the "x in only one command (which summons lots of other command blocks)" maybe someday specific terms will emerge for the types...

I initially read it as "McFunctions". I wasn't as surprised as I should have been that a fast food chain was running a cloud service

Picolisp doing raw LLVM-IR implementation. Works.

tbh I firslty thought it will be emitting red stone

There is a Minecraft HDL project but it's a fairly limited flow IIRC