(Lua) Simple Class

--[[
author: Alundaio (aka Revolucas)
A function that creates a new class-like table suitable for combining table properties.
It is very simple, only 20 lines and it is very aesthetically pleasing to define new 'classes'
ex 1. Class "new_class"
ex 2. Class "new_class" (inherit)
ex 3. Class "new_class" (inherit1,inherit2,...)

The only requirement is that you need to give _G a metatable where 'this' returns the table
being indexed, which in my opinion is useful on it's own as it will return the current table
environment.

example usage:

Class "human"
function human:__init(name)
    self.name = name
end
function human:printf()
    print(self.name)
end

Class "girl" (human)
function girl:__init(name)
    self.inherited[1].__init(self,name)
end

Class "boy" (human)
Class "transgender" (boy,girl)

local instance = transgender("bob")
instance:printf() -- prints 'bob'
--]]

-- Set _G metatable where 'this' returns self of __index.
setmetatable(_G, {__index=function(t,k)
    if (k == "this") then
        return t
    end
    return rawget(_G,k)
end
})

function Class(name)
    this[name] = setmetatable({},{
        __index = getmetatable(_G).__index,
        __call = function(t,...)
            local o = setmetatable({},{__index=t})
            o:__init(...)
            return o
        end
    })
    return function(...)
        local p = {...}
        this[name].inherited = p
        getmetatable(this[name]).__index=function(t,k)
            for i,v in ipairs(p) do
                local ret = rawget(v,k)
                if (ret ~= nil) then
                    return ret
                end
            end
            return getmetatable(_G).__index(_G,k)
        end
    end
end