Re: Save `nil' from the mutant void, preserve the truth of falsehood, prevent the falsehood of truth

[Stefan Monnier <monnier@iro.umontreal.ca>]

> Two one-liners not even a Perl devotee could love:
> (prog1 #1=(fboundp ()) (unintern #1#))

Let's see how many lines of defenses you broke in the above code:
- use of #1= in code: very bad.
- unintern takes a symbol as argument, not a boolean, so it should not
  be called with the return value of (fboundp ...)
- calling unintern without an obarray arg is a bad idea.

Maybe we should make the second argument mandatory.

> Sometimes, I'm able to recover `nil' long enough to save the session,
> but even then i've not any reasonable surety that the busted `nil' is
> a correct `nil'.

The real nil is safely stored in a C variable `Qnil' which you should be
able to get via something like (not t).  But I don't think Elisp lets
you re-intern it, since `intern' only takes a string rather than a symbol.


        Stefan