Re: Logging changes of a weak table

[Zhao Han <hz@...>]

What if the value is not a table? 

---

tab = {}

setmetatable(tab, {__mode = 'v'})

r = function() end

tab['key'] = r

r = nil

collectgarbage()

—

When ‘r' is collected, how could ‘tab’ know that?

Thanks.

/hz

在 2018年9月3日，上午8:32，Oliver Kroth <oliver.kroth@nec-i.de> 写道：

Am 03.09.2018 um 17:18 schrieb Zhao Han:

Hi, All,

For a weak table, is it possible to use some meta table tricks to track the changes of the table?

e.g. when a key or value get collected, print a message.

Best Regards,
/hz

You could try to use the __gc field at a metatable at the objects that are going to get collected

--
Oliver