Re: 7 logical-xor implementations in source tree

[Alan Mackenzie]

Hello, Philippe.

On Sun, Jul 28, 2019 at 09:09:01 +0200, Philippe Schnoebelen wrote:
> On 2019/07/25 14:07, Mattias Engdegård wrote:
> > 25 juli 2019 kl. 01.44 skrev Basil L. Contovounesios <address@hidden>:


> > bool-equal, bool-equiv, bool=, bool-eq are all fine as far as I'm 
> > concerned. `xnor' and `nxor', not so much.
> > Racket has `boolean=?', but presumably it only copes with #t/#f.
> > I'll be using `equiv' as placeholder below for brevity.

> I like the name `iff'  for this function.

No, please don't use the name `iff' here.  In mathematical circles, iff
means "if and only if", and has done for many decades/several centuries.
Introducing it into Emacs with a radically different meaning will be
jarring in the extreme to anybody with a maths background.

> >>> - There's no use for it, currently.  If we can't find any use for it,
> >>>  I'm not sure it deserves to be in subr.el.

> I use the function a lot in ert tests, like in

>       (should (iff (null somelist) (zerop (length somelist))))

> --phs

-- 
Alan Mackenzie (Nuremberg, Germany).