Lua simple class

simpleclass.lua

function simpleclass(base)
    return setmetatable(base, {
        __call = function(t, ...)
            local obj = setmetatable({}, t)
            if rawget(t, '__new') then
                t.__new(obj, ...)
            end
            return obj
        end
    })
end

nn = simpleclass({
    -- constructor
    __new = function(self, name1)
        print("__new"..name1)
        self:m1()
    end,

    -- destructor
    __gc = function(self)
        print("run __gc")
    end,

    -- metamethods
    __len = function(self)
        print("run __len")
        return 100
    end,
    __tostring = function(self)
        print("run __tostring")
        return "nn"
    end,

    -- class methods, properties
    class_p1 = 123,
    class_m1 = function()
        print("class_m1")
    end,

    -- methods, properties
    __index = {
        p1 = 'p1p1',
        p2 = 'p2p2',

        m1 = function(self)
            print("m1")
            nn.class_m1()
        end,
    }
})

aa = nn('aaa')
print(aa, #aa)
print(aa.p1, aa.m1, aa:m11())

print(nn.class_p1, nn.class_m1())
print(nn.m1)  -- m1 is object method, invisit in class