Re: Should undefined behavior be encouraged in Emacs?

[Dave Abrahams]

on Mon Oct 03 2011, Richard Stallman <rms-AT-gnu.org> wrote:

>     My impression is that Emacs built-ins are generally supposed to
>     have defined behavior, so that Emacs is easier to use reliably.
>
> What is the meaning of "defined" or "undefined", here?
> Is it a matter of whether the documentation says what happens in that case?
>
> In simple cases such as (goto-char -5), users tend to see what the
> behavior is, and are likely to write code that depends on it, even if
> it isn't documented.  Thus, leaving it undocumented doesn't mean that
> we can change it and nobody will notice.

If you make it a hard, inescapable error, that won't happen.

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com