From: Michael Albinus <michael.albinus@gmx.de>
To: Lars Ingebrigtsen <larsi@gnus.org>
Cc: Eli Zaretskii <eliz@gnu.org>, emacs-devel@gnu.org
Subject: Re: master e315544: ; * src/fileio.c (Fdirectory_append): Doc fix.
Date: Sun, 25 Jul 2021 09:59:44 +0200 [thread overview]
Message-ID: <87a6man7rj.fsf@gmx.de> (raw)
In-Reply-To: <87wnpfynqn.fsf@gnus.org> (Lars Ingebrigtsen's message of "Sun, 25 Jul 2021 07:19:12 +0200")
Lars Ingebrigtsen <larsi@gnus.org> writes:
>>>> I would expect "foo/bar", meaning that all leading slashes in COMPONENTS
>>>> are removed.
>>>
>>> Well, I think that's over into DWIM-land again (which is what
>>> expand-file-name does, and this function deliberately doesn't do).
>>
>> expand-file-name and file-name-as-directory are functions which call a
>> handler, for example Tramp. directory-append is much cheaper, and if it
>> could do this string handling, I could avoid those functions. It would
>> be more performant.
>
> The reason `directory-append' is useful as a function at all (instead of
> just using `concat') is that we're very vague about the difference
> between a directory name and a file name in Emacs. That is, we treat
> "/tmp/" and "/tmp" as equivalent in more than 99% of cases when dealing
> with directories. This has naturally led to people setting
> `foo-directory' variables etc to something ending with a slash or not
> arbitrarily, which again means that you can't just use `concat' to
> construct file names.
>
> But "/bar.txt" does not happen naturally as a leaf file name, so I think
> it'd be counter-productive to have `directory-append' do anything
> particular about the start of file name components.
So (file-name-concat x y) is roughly equivalent to
(let (file-name-handler-alist)
(concat (file-name-as-directory x) y))
Perhaps this could be mentioned somewhere in the manual? This would also
precise, that leading slashes in COMPONENTS are kept.
Best regards, Michael.
next prev parent reply other threads:[~2021-07-25 7:59 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210724171858.1726.43078@vcs0.savannah.gnu.org>
[not found] ` <20210724171900.4A26D20D0A@vcs0.savannah.gnu.org>
2021-07-24 18:39 ` master e315544: ; * src/fileio.c (Fdirectory_append): Doc fix Michael Albinus
2021-07-24 18:51 ` Lars Ingebrigtsen
2021-07-24 19:04 ` Michael Albinus
2021-07-25 5:19 ` Lars Ingebrigtsen
2021-07-25 5:27 ` Stefan Monnier
2021-07-25 6:54 ` Lars Ingebrigtsen
2021-07-25 10:01 ` Kévin Le Gouguec
2021-07-25 10:23 ` Lars Ingebrigtsen
2021-07-25 11:50 ` Andreas Schwab
2021-07-25 13:05 ` Kévin Le Gouguec
2021-07-28 15:39 ` Lars Ingebrigtsen
2021-07-28 17:28 ` Michael Albinus
2021-07-30 11:36 ` Lars Ingebrigtsen
2021-07-25 7:59 ` Michael Albinus [this message]
2021-07-28 15:36 ` Lars Ingebrigtsen
2021-07-28 17:13 ` Michael Albinus
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