From: Emanuel Berg via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>
To: help-gnu-emacs@gnu.org
Subject: Re: [External] : Set the default-directory dynamically according to the buffer-file-name.
Date: Fri, 01 Oct 2021 09:09:35 +0200 [thread overview]
Message-ID: <87zgrtgr0w.fsf@zoho.eu> (raw)
In-Reply-To: CAGP6POJDHHPrFzdEkwaJdbu802Q4-=wCBbXUeLmbdCLkGvBqaQ@mail.gmail.com
Hongyi Zhao wrote:
>> (if (not WHATEVER)
>> (message "PROBLEM NOTIFICATION")
>> (DO-STUFF))
>>
>> If you want to stop everything and be sure the
>> message is seen, you might want to raise an error:
>>
>> (unless WHATEVER (error "PROBLEM")) ; End it all
>> (DO-STUFF)
>
> Do you mean this is a good practice for usage scenarios in
> production environments?
Well, yes, but also in every other environment where your
aspiration is to write good, idiomatic Lisp.
He is showing the syntax and how it is put together for
two scenarios.
But the more tricky question is another, namely when should
one use the first one (i.e., `message' the situation, then
branch out) and when is the situation in fact an `error', much
like division by zero?
(/ 1337 0) ; Arithmetic error
--
underground experts united
https://dataswamp.org/~incal
prev parent reply other threads:[~2021-10-01 7:09 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-29 14:31 Set the default-directory dynamically according to the buffer-file-name Hongyi Zhao
2021-09-29 14:50 ` Hongyi Zhao
2021-09-29 15:31 ` Tassilo Horn
2021-09-30 1:08 ` Hongyi Zhao
2021-09-30 3:37 ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-09-30 7:00 ` Hongyi Zhao
2021-09-30 7:39 ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-09-30 8:54 ` Hongyi Zhao
2021-09-30 9:58 ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-09-29 15:47 ` [External] : " Drew Adams
2021-10-01 4:41 ` Hongyi Zhao
2021-10-01 7:09 ` Emanuel Berg via Users list for the GNU Emacs text editor [this message]
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