As a lua programer, you learn the coding grammar, write down your code and it works. But you never know how it works behind this "black box". So it would be better to look into its core. How the VM ...

This code is easy to read, and I bet you can take an intuitive guess at what it does. Lua is not only easy to read, it is also very powerful. The real power of Lua comes from its extensible nature.