bug#55645: src/print.c; print_object changes make it impossible to compare elisp code across versions

[Eli Zaretskii <eliz@gnu.org>]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: 55645@debbugs.gnu.org, Eli Zaretskii <eliz@gnu.org>
> Date: Sun, 29 May 2022 15:15:38 +0200
> 
> Tom Gillespie <tgbugs@gmail.com> writes:
> 
> > Ah I think I know what is missing here. I'm not trying to compare arbitrary
> > elisp objects. I'm explicitly only trying to compare literal emacs lisp source
> > code and that has been extremely easy since at least emacs 24 (iirc it is
> > also the same in 23). The only issue I have encountered was a change in
> > iirc 27 of the default value for print-escape-newlines or something like that.
> 
> I'm just not convinced that there's a compelling use case here that
> would support the added maintenance burden of adding Yet Another
> Printing Variable here -- you're using prin1 to implement something that
> prin1 was never meant to support.  If you want to see whether some code
> is "the same", then I think you really have to read the forms in and
> compare the forms.
> 
> But perhaps Eli has an opinion; added to the CCs.

I think I'd need an example that demonstrates the issue, to make up my
mind.  Tom, can you describe the issue in more detail, and provide an
example or two?

Thanks.