Second query about to-be-closed variables
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- Subject: Second query about to-be-closed variables
- From: Arnaud Delobelle <arnodel@...>
- Date: 2022年1月14日 10:03:23 +0000
Hi all,
I have another question on the semantics of to-be-closed variables,
this time about error handling. Consider the following example
program
---- tbc2.lua ----
local function foo()
local t = {}
setmetatable(t, {__close = function() print(debug.getinfo(2).name) end})
local x <close> = t
error("stop")
end
-- Added for good measure
local function bar()
foo()
end
pcall(bar)
--- end ----
When I run this program with Lua 5.4.3, the output is
----
pcall
----
I would have expected "foo", because I thought that the close
metamethod would be called "on the way out" of foo. I haven't found
an explanation for the actual behaviour in the docs. I would like to
know the reasons for this - are they tied to the implementation of
to-be-closed variables, or is there a sound principle underlying this
behaviour?
Thanks in advance,
--
Arnaud