In Lua the user manual is the reference, so if the language does something different, it is considered a bug. If something is not described in the manual then i

In Lua the user manual is the reference, so if the language does something different, it is considered a bug. If something is not described in the manual then it is an implementation detail (unspecified) and code that relies on it is broken. This led to several alternative implementations, among which at least one (LuaJIT) implements completely a version of the language (Lua 5.1).