lua prototype ideas

-- isa

Object = {
    clone = function (self, ...)
        local obj = {}
        obj.__index = obj.__index or obj
        
        setmetatable(obj, self.mt or self)
        if obj.init then
            obj:init(...)
        end
        
        return obj
    end,
    isA = function (self, obj)
        return getmetatable(self) == (obj.mt or obj)
            or getmetatable(self):isA(obj)
    end
}
Object.__index = Object