Re: Lisp manual is incomplete w.r.t. mode-line-format

[Stefan Monnier]

>     It appears to still be true.  But it is not just the Elisp manual that
>     fails to mention this and should be fixed.  The `mode-line-format'
>     docstring does not mention it either.  Is it intentional behavior?

> Yes and no.  It has to do SOMETHING in this case, but it must not
> signal an error.  So this seems like the best thing for it to do.

Also it's convenient for the typical var which defaults to nil but might not
yet be loaded (i.e. where unbound and nil are somewhat equivalent).
Those same variables which would be tested with bound-and-true-p.

Of course we could also define (VAR THEN-FORMAT ELSE-FORMAT UNBOUND-FORMAT)
so the fourth element is used if the var is unbound instead of being nil.


        Stefan