Re: Yet another proposal for <toclose> (was Re: [ANN] Lua 5.4.0 (alpha) now available)

[Philipp Janda <siffiejoe@...>]

Am 29.06.19 um 07:29 schröbte pocomane:
> Of course you can simulate this with defer
>
> local obj = my_complex_object()
> defer getmetatable(obj).__close() end

Since function definitions allocate memory and thus can fail, this idiom 
isn't safe. You'd have to use the more awkward

local obj
defer
  if obj then
    getmetatable(obj).__close()
  end
end
obj = my_complex_object()


And then you realize that Lua may allocate memory during function 
*calls* (e.g. growing the stack). I don't think this is covered in the 
current <toclose> approach either.

Philipp