Re: stack module

[Marc Nieper-Wißkirchen]

Am Sa., 23. Mai 2020 um 22:51 Uhr schrieb Paul Eggert <address@hidden>:
>
> On 5/23/20 10:38 AM, Marc Nieper-Wißkirchen wrote:
> > But if "affirm" is fine with you, I would love to see it in a module.
> > Either in verify or assure or in a new module named affirm.
>
> Something like the attached?

That would be a good addition to Gnulib, indeed, I think. (And may
even already be used by a number of modules, which currently call
abort explicitly.)

I find the comments in your code very valuable. I may change only one
thing. Above the definition of affirm, you write "Unlike standard
'assert', this macro always compiles E even when NDEBUG is defined
...". I think it is better to change it to "... always evaluates E
even when ...". In fact, when the assumption is fulfilled, E must have
been evaluated. If the assumption fails we are in the realm of
undefined behavior, so we may as well claim that E has been evaluated.
This is important not only so that the side effects of the evaluation
of E are documented, but also to remind the user of a potentially
costly evaluation.