Self Summary: Lua Language（two useful links） and the difference between : and .

Here is a very useful website about learning Lua: http://tylerneylon.com/a/learn-lua/

Also, here is a detailed teaching link: http://www.lua.org/pil/contents.html

Here I just want to talk about the difference of : and . in Lua: 

Function tablename:fn(...) is the same as function tablename.fn(self, ...). The : just adds a first arg called self.

Class behaviour is built upon the basis of table in Lua. For details please turn to the website.