From: Eli Zaretskii <eliz@gnu.org>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: emacs-devel@gnu.org
Subject: Re: emacs-26 8f18d12: Improve documentation of decoding into a unibyte buffer
Date: Tue, 28 May 2019 18:18:07 +0300 [thread overview]
Message-ID: <83woiazjyo.fsf@gnu.org> (raw)
In-Reply-To: <jwvsgsyokto.fsf-monnier+emacs@gnu.org> (message from Stefan Monnier on Tue, 28 May 2019 07:55:40 -0400)
> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: emacs-devel@gnu.org
> Date: Tue, 28 May 2019 07:55:40 -0400
>
> >> Hence according to my reading of the code, this call to
> >> string-as-unibyte will always just return its argument unchanged.
> > That's not entirely true, because encode-coding-char can return a multibyte
> > string.
>
> That's weird. When would that happen?
"Use the source, Luke!"
(let* ((str1 (string-as-multibyte (string char)))
(str2 (string-as-multibyte (string char char)))
(found (find-coding-systems-string str1))
enc1 enc2 i1 i2)
(if (and (consp found)
(eq (car found) 'undecided))
str1 <<<<<<<<<<<<<<<<<<<<<<<<<
If we return here, the value is str1, which is a multibyte string, see
how it was calculated.
The easiest use case is this:
(multibyte-string-p (encode-coding-char ?a 'utf-8))
=> t
I didn't think enough about this to figure out if there can be less
trivial use cases. If you can describe all the cases where
find-coding-systems-string will return a list whose 'car' is
'undecided', my hat off to you.
next prev parent reply other threads:[~2019-05-28 15:18 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190525191039.14136.23307@vcs0.savannah.gnu.org>
[not found] ` <20190525191040.CCD6C207F5@vcs0.savannah.gnu.org>
2019-05-25 19:41 ` [Emacs-diffs] emacs-26 8f18d12: Improve documentation of decoding into a unibyte buffer Stefan Monnier
2019-05-25 19:59 ` Eli Zaretskii
2019-05-25 20:15 ` Eli Zaretskii
2019-05-25 21:11 ` Stefan Monnier
2019-05-25 21:27 ` Stefan Monnier
2019-05-26 2:37 ` Eli Zaretskii
2019-05-27 9:47 ` Robert Pluim
2019-05-27 12:24 ` Stefan Monnier
2019-05-27 13:02 ` Robert Pluim
2019-05-27 13:32 ` Stefan Monnier
2019-05-27 13:49 ` Robert Pluim
2019-05-27 16:53 ` Eli Zaretskii
2019-05-28 6:23 ` Robert Pluim
2019-05-28 14:57 ` Eli Zaretskii
2019-05-28 3:08 ` Stefan Monnier
2019-05-28 4:40 ` Eli Zaretskii
2019-05-28 11:55 ` Stefan Monnier
2019-05-28 15:18 ` Eli Zaretskii [this message]
2019-05-28 17:43 ` Stefan Monnier
2019-05-28 18:58 ` Eli Zaretskii
2019-05-28 19:35 ` Eli Zaretskii
2019-05-28 23:44 ` Stefan Monnier
2019-05-29 14:33 ` Eli Zaretskii
2019-05-27 16:51 ` Eli Zaretskii
2019-05-27 19:17 ` Stefan Monnier
2019-05-28 2:30 ` Eli Zaretskii
2019-05-28 2:56 ` Stefan Monnier
2019-05-28 4:17 ` Eli Zaretskii
2019-05-28 6:21 ` Robert Pluim
2019-05-28 11:53 ` Stefan Monnier
2019-05-28 11:54 ` Stefan Monnier
2019-05-28 15:11 ` Eli Zaretskii
2019-05-28 17:25 ` Stefan Monnier
2019-05-28 18:51 ` Eli Zaretskii
2019-05-28 23:39 ` Stefan Monnier
2019-05-29 2:45 ` Eli Zaretskii
2019-05-29 16:28 ` Stefan Monnier
2019-05-29 18:19 ` Eli Zaretskii
2019-05-29 18:58 ` Stefan Monnier
2019-05-29 19:09 ` Eli Zaretskii
2019-05-29 19:50 ` Stefan Monnier
2019-05-27 16:43 ` Eli Zaretskii
2019-05-27 16:42 ` Eli Zaretskii
2019-05-27 19:13 ` Stefan Monnier
2019-05-27 16:40 ` Eli Zaretskii
2019-05-27 20:17 ` Richard Stallman
2019-05-28 2:36 ` Eli Zaretskii
2019-05-28 7:06 ` Robert Pluim
2019-05-28 14:59 ` Eli Zaretskii
2019-05-28 15:11 ` Robert Pluim
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