Re: unwind-protect within while-no-input

[Eli Zaretskii <eliz@gnu.org>]

> From: Spencer Baugh <sbaugh@janestreet.com>
> Date: Wed, 08 May 2024 10:38:11 -0400
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> Your code does not run the unwind forms when run inside a
> >> while-no-input.
> >
> > Why should it?  When while-no-input is interrupted by input, it
> > conceptually is not "quitting"; the fact that it uses quit-flag is an
> > internal implementation detail.
> 
> Because there might be something I want to clean up.
> 
> For example, my code might create a process or temporary directory which
> should be deleted even if interrupted by input.
> 
> > If you want the unwind forms to run when while-no-input is interrupted
> > by input, simply do it: while-no-input provides a clear documented
> > indication that it was interrupted by input, and you can use that to
> > decide whether to run the unwind forms in that case.
> 
> What concretely are you suggesting?  Could you give an example in code?

I cannot give a concrete example, because even now you describe more
and more details of your code that you haven't disclosed previously.
So any code I will show will most probably not work for you because of
those undisclosed details.

I can only say what I mean generally: the unwind forms are just code,
so when you detect that while-no-input was interrupted by some input,
simply call those unwind forms "by hand".  What exactly that means and
how exactly to do that is something the depends on those details and
on what exactly your unwind forms need to do.

> Note that my code doesn't require while-no-input or always run inside
> while-no-input - it's just that whenever my code happens to be inside a
> while-no-input, my code should still do the cleanup.

As I said, while-no-input provides an indication whether it was
interrupted, so you can easily do whatever you need to do in that
case.