bug#70868: 30.0.50; pp--insert-lisp prints small integers as characters

[Michael Heerdegen via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Mattias Engdegård <mattias.engdegard@gmail.com> writes:

> 11 maj 2024 kl. 13.09 skrev Michael Heerdegen <michael_heerdegen@web.de>:
>
> > (let ((print-integers-as-characters t))
> >   (princ ?\; (current-buffer)))
> > 
> > prints "?;" instead of "?\;" - it fails to quote the character.  Binding
> > `print-quoted' doesn't help.  This needs to be fixed.
>
> Does it? Not defending the code in any way, but `princ` isn't supposed
> to quote anything. If you want it in a form that can be read back in,
> use `prin1`.
>
> We do get to make up the rules, though. Perhaps it should print 57 as
> `;` instead of `?;`. It's not clear what makes the most sense here.

Thanks Andreas and Mattias for bringing up the missing point.

I don't have an opinion about - and don't want to answer - what `princ'
should print here, and rather stick to original problem of this bug
report.

It is quite obvious that we need to change `pp--insert-lisp' to use
`prin1' in this case - again: we changed several other places in the
past in the same way.

Does anyone have a clue if there is a reason why we should not simply
change _all_ occurrences of `princ' to `prin1' in `pp--insert-lisp' and
related functions?  It seems that when there is a difference we always
want `prin1', i.e. readable, printing.

BTW, is there a rule of thumb that makes it possible to remember which
of the two does the readable printing?  I'm always confusing them or
even don't get the problem.


Thanks,

Michael.