GNU bug report logs - #966
keybinding involving Ctrl and Shift and letter

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Message #5 received at submit <at> emacsbugs.donarmstrong.com (full text, mbox):

From: xah lee <xah <at> xahlee.org>
To: bug-gnu-emacs <at> gnu.org
Subject: keybinding involving Ctrl and Shift and letter
Date: Thu, 11 Sep 2008 20:46:22 -0700

This seems to be a bug.

i'm trying to set keybindings for both Ctrl+n and Ctrl+Shift+n, by:


(global-set-key (kbd "C-N") 'f1)
(global-set-key (kbd "C-n") 'f2)

however, that doesn't work.
Emacs will take both Ctrl+Shift+n and Ctrl+Shift+n to be whichever is  
evaluated last. In this case, f2.

But the following works:

(global-set-key (kbd "C-S-n") 'f1)
(global-set-key (kbd "C-n") 'f2)

This seems to contradict with Meta's ways. That is (kbd "M-N") works  
but not (kbd "M-S-n").

  Xah
∑ http://xahlee.org/

☄

In GNU Emacs 22.2.1 (powerpc-apple-darwin8.11.0, Carbon Version 1.6.0)
 of 2008-04-05 on g5.tokyo.stp.isas.jaxa.jp
Windowing system distributor `Apple Inc.', version 10.4.11
configured using `configure  '--prefix=/Applications/Emacs.app/ 
Contents/Resources' '--with-carbon' '--without-x' '--libexecdir=/ 
Volumes/Emacs/Emacs.app/Contents/MacOS/libexec' 'CFLAGS=-Os -arch  
i386 -arch ppc -isysroot /Developer/SDKs/MacOSX10.4u.sdk -DUSE_ATSUI - 
DUSE_MAC_TSM''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
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  locale-coding-system: iso-8859-1
  default-enable-multibyte-characters: t



☄

Message #10 received at 966-done <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Chong Yidong <cyd <at> stupidchicken.com>
To: xah lee <xah <at> xahlee.org>
Cc: 966-done <at> debbugs.gnu.org
Subject: keybinding involving Ctrl and Shift and letter
Date: Wed, 17 Sep 2008 16:08:31 -0400

> i'm trying to set keybindings for both Ctrl+n and Ctrl+Shift+n, by:
>
> (global-set-key (kbd "C-N") 'f1)
> (global-set-key (kbd "C-n") 'f2)
>
> however, that doesn't work.
> Emacs will take both Ctrl+Shift+n and Ctrl+Shift+n to be whichever is  
> evaluated last. In this case, f2.
>
> But the following works:
>
> (global-set-key (kbd "C-S-n") 'f1)
> (global-set-key (kbd "C-n") 'f2)
>
> This seems to contradict with Meta's ways.

This is a legacy of ASCII.  Taking a look at an ASCII chart, you'll see
that ^A (control-a) through ^Z (control-z) map to ASCII codes 1 through
26, and these control keys are not case sensitive: control-a is
equivalent to control-A.

Emacs extends ASCII, which allows us to define things like C-] which are
not present in ASCII.  However, (kbd "C-N") and (kbd "C-n") still both
evaluate to ^N.

Message #11 received at 966-done <at> emacsbugs.donarmstrong.com (full text, mbox):

From: xah lee <xah <at> xahlee.org>
To: Chong Yidong <cyd <at> stupidchicken.com>
Cc: 966-done <at> debbugs.gnu.org
Subject: Re: keybinding involving Ctrl and Shift and letter
Date: Wed, 17 Sep 2008 15:48:00 -0700

umm...

thanks for the answer.

I think there is still a problem, that is, inconsistency with the  
meta notation.

Namely, when defining a key with Ctrl or Meta with a Shift and a  
letter, when it is Meta,

(global-set-key (kbd "M-N") 'f)
works but
(global-set-key (kbd "M-S-n") 'f) does not work.

But with Ctrl, it is the the other way around.

Shouldn't emacs make "M-S-n" notation work and not "M-N", so that it  
is consistant with the Control?

In summary, the notation for a Meta/Control+Shift+‹letter›  
keybinding used in macro is not consistant. For Meta, "-N" is  
effective but for Control, "-S-n" is effective.

  Xah
∑ http://xahlee.org/

☄


On Sep 17, 2008, at 1:08 PM, Chong Yidong wrote:

> i'm trying to set keybindings for both Ctrl+n and Ctrl+Shift+n, by:
>
> (global-set-key (kbd "C-N") 'f1)
> (global-set-key (kbd "C-n") 'f2)
>
> however, that doesn't work.
> Emacs will take both Ctrl+Shift+n and Ctrl+Shift+n to be whichever is
> evaluated last. In this case, f2.
>
> But the following works:
>
> (global-set-key (kbd "C-S-n") 'f1)
> (global-set-key (kbd "C-n") 'f2)
>
> This seems to contradict with Meta's ways.

This is a legacy of ASCII.  Taking a look at an ASCII chart, you'll see
that ^A (control-a) through ^Z (control-z) map to ASCII codes 1 through
26, and these control keys are not case sensitive: control-a is
equivalent to control-A.

Emacs extends ASCII, which allows us to define things like C-] which are
not present in ASCII.  However, (kbd "C-N") and (kbd "C-n") still both
evaluate to ^N.

☄

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