bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element

[MON KEY <monkey@sandpframing.com>]

On Thu, Aug 19, 2010 at 12:18 PM, Chong Yidong <cyd@stupidchicken.com> wrote:
> MON KEY <monkey@sandpframing.com> writes:
>
>> So why would/should Emacs let me create a bool-vectors that I can
>> neither set nor get without signalling an error?
>
> You can vconcat them.
>

Yep:

(let* ((ab (make-bool-vector 1 t))
      (abeq (cons ab ab)))
 (vconcat (car abeq) (cdr abeq)))

;=>[t t]

But, again, where is the `t' or `nil'?

(let* ((ab (make-bool-vector 0 t))
      (abeq (cons ab ab)))
 (vconcat (car abeq) (cdr abeq)))

;=> []

The manual says a `t' or `nil' "must" be there.

--
/s_P\