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From: | arthur miller |
Subject: | Sv: Is this a bug in while-let or do I missunderstand it? |
Date: | Sat, 9 Nov 2024 13:47:07 +0000 |
>> least very unintuitive behaviour.
>
>Why? Pretty much all implementations of the ‘while’ loop in all
>languages I’ve seen re-evaluate the condition on every iteration.
That wasn't the un-intuitive part :-).
If it wasn't clear, the unintuitive part is that while-let was to
establish the local environment, so that we don't need to type:
(let ((som-var (init-form)))
(while some-var
... ))
At least is how I understand the purpose of if-let, when-let and while-let.
Från: Yuri Khan <yuri.v.khan@gmail.com>
Skickat: den 9 november 2024 14:41 Till: arthur miller <arthur.miller@live.com> Kopia: emacs-devel@gnu.org <emacs-devel@gnu.org> Ämne: Re: Is this a bug in while-let or do I missunderstand it? On Sat, 9 Nov 2024 at 20:38, arthur miller <arthur.miller@live.com> wrote:
> >I expect the binding is writable *but* it gets re-assigned on each iteration. > > Yes. > I have already posted the macro expansions in respone to Phillip. > It is quite clear what is going on. I think it is a bug, or at > least very unintuitive behaviour. Why? Pretty much all implementations of the ‘while’ loop in all languages I’ve seen re-evaluate the condition on every iteration. |
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