Re: Shrinking the C core

[Eli Zaretskii]

> From: Ihor Radchenko <yantar92@posteo.net>
> Cc: ams@gnu.org, incal@dataswamp.org, emacs-devel@gnu.org
> Date: Mon, 21 Aug 2023 11:56:20 +0000
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> (let ((a 10))
> >>   (setq a (+ a 100))
> >>   (floor a nil))
> >> 
> >> During compilation of the above code, the compiler will know that a is a
> >> positive integer.
> >
> > It will?  What happens if a overflows?
> 
> It will not, right? Because we do know all the values at compile time in
> the above example.

In toy programs, perhaps.  But not in real life.  We want to be able
to write real-life programs in Lisp, not just toy ones.

> > If you want to program in C or Fortran, then program in C or Fortran.
> > Lisp is an interpreted environment that traditionally includes safety
> > nets.  People actually complain to us, and rightfully so, when Emacs
> > crashes or produces corrupted results instead if signaling an error
> > pointing out invalid input or other run-time problems.
> 
> I did not mean to disable checks. I just meant that when the types and
> possibly value ranges are known at compile time, these checks can be
> safely omitted. Without compromising safety.

Not in ELisp, they cannot.  Someone already explained why.