Simple OO

local classes={
    base={
        className="base"
    }
}

local function addClass(name,base,tab)
    tab.className=name
    tab.super=base
    classes[name]=setmetatable(tab,{
        __index=base,
        __call=function(self,...)
            local new=setmetatable({},{__index=self})
            if new.new then new:new(...) end
            return new
        end
    })
    return tab
end

return {
    class=function(name)
        return function(arg1)
            if type(arg1)=="string" then
                return function(arg2)
                    return addClass(name,classes[arg1],arg2)
                end
            end
            return addClass(name,classes.base,arg1)
        end
    end
}