Given Lua's age and use in so many projects, I was under the impression that it was somewhat stable.
Basically, my interest in Lua is this: I'd like to build a personal computing environment that is oriented towards end-user empowerment the way I remember them being in the pre-web era. To that end, employing a relatively simple interpreted language to build as much of the environment as possible is desired such that the end user is able to read and modify large portions of it, as well as create their own tools. Something on the level of Visual Basic or HyperCard would be useful for the GUI portions, and Lua is popular enough to have a lot of learning resources available, so it was an option I was considering.
It is fairly stable in terms of syntax. Just that features like Unicode support etc. tend to be difficult to implement without deep changes. For OS dev, look into Node9 and
https://www.lua.org/wshop13/Cormack.pdf
There have been quite a few attempts at building OSes with Lua as main system/userland language. There are very few Lua implementations that can bootstrap so you still need a bit of non-Lua code as glue for the interpreter bits if not for juggling pointers.
Basically, my interest in Lua is this: I'd like to build a personal computing environment that is oriented towards end-user empowerment the way I remember them being in the pre-web era. To that end, employing a relatively simple interpreted language to build as much of the environment as possible is desired such that the end user is able to read and modify large portions of it, as well as create their own tools. Something on the level of Visual Basic or HyperCard would be useful for the GUI portions, and Lua is popular enough to have a lot of learning resources available, so it was an option I was considering.