From: Max Mikhanosha <max.mikhanosha@protonmail.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: emacs-devel@gnu.org
Subject: Re: Bugfix for utf-8 XTerm/MinTTY and (set-input-meta-mode t)
Date: Tue, 01 Jun 2021 17:28:59 +0000 [thread overview]
Message-ID: <JJmjIOEo4lfOIE60a8PfL2ixbfsOelU2TzvzBsj9Zr0tCxUWdLouQydt_2UTpHFlL0bKwczma4hdVixXLIKVpePHuQoQrP4rjZsF1CdZskk=@protonmail.com> (raw)
In-Reply-To: <83k0ndzfxr.fsf@gnu.org>
On Tuesday, June 1st, 2021 at 12:51 PM, Eli Zaretskii <eliz@gnu.org> wrote:
> > Date: Tue, 01 Jun 2021 16:19:40 +0000
>
> > From: Max Mikhanosha max.mikhanosha@protonmail.com
> >
> > Both XTerm and MinTTY, when configured to send meta modifier as 8th bit while in utf-8 mode, will first add 8th bit, and then encode resulting character with utf-8. For example Meta-X is encoded as ?x+120 = #248 codepoint, encoded as 0xc3,0xb8
>
> If these terminal emulators send M-x as 248 decimal, then how do they
> send the Latin character ø, whose codepoint is 248 decimal?
Exactly the same 0xc3,0xb8. Its point of the encode meta-key in the 8th bit mechanics, that you give up ability to type upper half of ASCII table (128-255) instead using them to indicate meta key. Its a life-safer for those of us using vi, (on in Emacs case evil), otherwise sending meta keys as Esc <key> really interferes with vi mode where Esc key is super-special.. You can still insert these characters by doing quoted-insert, ie C-v M-x and it will insert ø
To illustrate my point, this patch restores the parity/functionality between non-utf-8 enabled and utf-8 enabled terminal
Before the patch, emacs is configured
non-utf8-xterm & emacs with (set-input-meta-mode nil), meta-x produces ø
non-utf8-xterm & emacs with (set-input-meta-mode t), meta-x produces M-x
utf8-xterm & emacs with (set-input-meta-mode nil), meta-x produces ø
utf8-xterm & emacs with (set-input-meta-mode t), meta-x produces weird garbage, C-v M-x produces weird garbage
After the patch
non-utf8-xterm & emacs with (set-input-meta-mode nil), meta-x produces ø
non-utf8-xterm & emacs with (set-input-meta-mode t), meta-x produces M-x, C-v M-x produces ø
utf8-xterm & emacs with (set-input-meta-mode nil), meta-x produces ø
utf8-xterm & emacs with (set-input-meta-mode t), meta-x produces M-x, C-v M-x produces ø
I also typed some stuff in Russian and nothing seem to be broke in UTF8 in general. If there is a concern that this patch can break something, maybe one way forward is to rework it to add another meaning to meta mode flag, like (set-input-meta-mode 'utf8), which would trigger what my patch is doing. But current behavior, where meta_key is checked before utf-8 decoding is obviously a bug, as it produces garbage input by treating utf-8 encoding itself as having meta modifiers.
next prev parent reply other threads:[~2021-06-01 17:28 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-01 16:19 Bugfix for utf-8 XTerm/MinTTY and (set-input-meta-mode t) Max Mikhanosha
2021-06-01 16:51 ` Eli Zaretskii
2021-06-01 17:28 ` Max Mikhanosha [this message]
2021-06-01 17:38 ` Eli Zaretskii
2021-06-01 18:01 ` Max Mikhanosha
2021-06-01 18:18 ` Eli Zaretskii
2021-06-01 18:35 ` Max Mikhanosha
2021-06-01 18:46 ` Eli Zaretskii
2021-06-02 9:22 ` Max Mikhanosha
2021-06-02 12:16 ` Andreas Schwab
2021-06-03 5:42 ` Max Mikhanosha
2021-06-05 14:20 ` Eli Zaretskii
2021-06-01 17:29 ` Eli Zaretskii
2021-06-01 17:45 ` Max Mikhanosha
2021-06-01 17:52 ` Eli Zaretskii
2021-06-01 18:10 ` Max Mikhanosha
2021-06-01 17:04 ` Andreas Schwab
2021-06-01 17:36 ` Max Mikhanosha
2021-06-01 20:06 ` Stefan Monnier
2021-06-02 10:21 ` Max Mikhanosha
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