Fengari helps to manage and switch between different versions of packages.
Based on luaver.
NOTES (to fix): LuaJit does not provide .tar download anymore. (Luaver still tries to download the .tar) Moonscript only works correctly with lua5.1 from my experiance other versions like 5.4 cause problems eather for moon or other Luarocks packages that use it like Busted.