Lua is a great language and this is cool research. But cool as it is, saying that Lua "now has optional typing" because a research extension to the language has

Lua is a great language and this is cool research. But cool as it is, saying that Lua "now has optional typing" because a research extension to the language has implemented it isn't really realistic. By that token, you could say that Java has every imaginable language feature because in the 00's, adding features to Java was how most PL research was done. You can have Lua lots of ways: if you use standard Lua, then it comes with a large number of nice C libraries; if you use LuaJIT then it's very fast; if you use this research version, then it has optional types. But you can't have all of these ways at the same time.