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Re: 7 logical-xor implementations in source tree
From: |
Marcin Borkowski |
Subject: |
Re: 7 logical-xor implementations in source tree |
Date: |
Sun, 28 Jul 2019 21:43:19 +0200 |
User-agent: |
mu4e 1.1.0; emacs 27.0.50 |
On 2019-07-28, at 10:04, Alan Mackenzie <address@hidden> wrote:
> 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.
Out of curiosity: how is that a "radically different meaning"? I assume
that we are talking about a function `iff' such that
(iff nil nil) evaluates to t
(iff nil <non-nil>) evaluates to nil
(iff <non-nil> nil) evaluates to nil
(iff <non-nil> <non-nil>) evaluates to t (or perhaps the latter
<non-nil>)
This could of course be generalized to n arguments, though I'm not sure
whether anyone would want that (as with xor, there is more than one
"natural" way to do that).
If so, this is precisely the meaning we are talking about, no?
Also, Wikipedia claims that "iff" is relatively new (the fifties), btw.
Best,
--
Marcin Borkowski
http://mbork.pl
- 7 logical-xor implementations in source tree, Oleh Krehel, 2019/07/22
- Re: 7 logical-xor implementations in source tree, Basil L. Contovounesios, 2019/07/22
- Re: 7 logical-xor implementations in source tree, Basil L. Contovounesios, 2019/07/24
- Re: 7 logical-xor implementations in source tree, Stefan Monnier, 2019/07/24
- Re: 7 logical-xor implementations in source tree, Basil L. Contovounesios, 2019/07/24
- Re: 7 logical-xor implementations in source tree, Mattias Engdegård, 2019/07/25
- Re: 7 logical-xor implementations in source tree, Paul Eggert, 2019/07/25
- Re: 7 logical-xor implementations in source tree, Mattias Engdegård, 2019/07/25
- Re: 7 logical-xor implementations in source tree, Philippe Schnoebelen, 2019/07/28
- Re: 7 logical-xor implementations in source tree, Alan Mackenzie, 2019/07/28
- Re: 7 logical-xor implementations in source tree,
Marcin Borkowski <=
- Re: 7 logical-xor implementations in source tree, Alan Mackenzie, 2019/07/30
- Re: 7 logical-xor implementations in source tree, Philippe Schnoebelen, 2019/07/30
- Re: 7 logical-xor implementations in source tree, Andy Moreton, 2019/07/30
- Re: 7 logical-xor implementations in source tree, Stefan Monnier, 2019/07/30
- Re: 7 logical-xor implementations in source tree, Barry Fishman, 2019/07/30
- Re: 7 logical-xor implementations in source tree, Richard Stallman, 2019/07/30
- Re: 7 logical-xor implementations in source tree, Barry Fishman, 2019/07/31
- Re: 7 logical-xor implementations in source tree, Stefan Monnier, 2019/07/31
- Re: 7 logical-xor implementations in source tree, Basil L. Contovounesios, 2019/07/31
- Re: 7 logical-xor implementations in source tree, Michael Heerdegen, 2019/07/31