. is undefined (when pressing C-.): is ssh behaving odd?

. is undefined (when pressing C-.): is ssh behaving odd?

[Luca Ferrari]

Hi all,
I'm trying to get embark to work with a very simple setup, that is:

(use-package embark
  :ensure t

  :bind
  (("C-." . embark-act)         ;; pick some comfortable binding
   ("M-." . embark-dwim)        ;; good alternative: M-.
   ("C-h B" . embark-bindings)) ;; alternative for `describe-bindings'

  :init
  (setq prefix-help-command #'embark-prefix-help-command)  )


So far, so good, if I do M-x embark I can see that is bound to C-. as expected.
But when I press C-. I got ". is undefined".
I'm using emacs thru ssh, if that matters, which I suspect is
something that6 is going to handle C, even if C-x C-f (as an example)
works as expected.
Remapping C-. to M-. makes emabrk-act to work, so is something related
to C, but why is not showing up with other C-based commands?

Thanks,
Luca

Re: . is undefined (when pressing C-.): is ssh behaving odd?

[Robert Pluim]

>>>>> On Fri, 3 Dec 2021 12:34:10 +0100, Luca Ferrari <fluca1978@gmail.com> said:

    Luca> So far, so good, if I do M-x embark I can see that is bound to C-. as expected.
    Luca> But when I press C-. I got ". is undefined".
    Luca> I'm using emacs thru ssh, if that matters, which I suspect is
    Luca> something that6 is going to handle C, even if C-x C-f (as an example)

tty's canʼt produce 'C-.'

Robert
-- 

Re: . is undefined (when pressing C-.): is ssh behaving odd?

[Luca Ferrari]

On Fri, Dec 3, 2021 at 3:33 PM Robert Pluim <rpluim@gmail.com> wrote:
>
> >>>>> On Fri, 3 Dec 2021 12:34:10 +0100, Luca Ferrari <fluca1978@gmail.com> said:
>
>     Luca> So far, so good, if I do M-x embark I can see that is bound to C-. as expected.
>     Luca> But when I press C-. I got ". is undefined".
>     Luca> I'm using emacs thru ssh, if that matters, which I suspect is
>     Luca> something that6 is going to handle C, even if C-x C-f (as an example)
>
> tty's canʼt produce 'C-.'

Could you elaborate a little more about that? Rationale and/or
possible fix if any?

Thanks,
Luca

Re: . is undefined (when pressing C-.): is ssh behaving odd?

[Robert Pluim]

>>>>> On Mon, 6 Dec 2021 18:21:16 +0100, Luca Ferrari <fluca1978@gmail.com> said:

    Luca> On Fri, Dec 3, 2021 at 3:33 PM Robert Pluim <rpluim@gmail.com> wrote:
    >> 
    >> >>>>> On Fri, 3 Dec 2021 12:34:10 +0100, Luca Ferrari <fluca1978@gmail.com> said:
    >> 
    Luca> So far, so good, if I do M-x embark I can see that is bound to C-. as expected.
    Luca> But when I press C-. I got ". is undefined".
    Luca> I'm using emacs thru ssh, if that matters, which I suspect is
    Luca> something that6 is going to handle C, even if C-x C-f (as an example)
    >> 
    >> tty's canʼt produce 'C-.'

    Luca> Could you elaborate a little more about that? Rationale and/or
    Luca> possible fix if any?

There are limitations to the keys that can be produced when using a
tty (such as when youʼre logged in over ssh, or running 'emacs
-nw'). One of those is that certain Ctrl combinations simply won't
work: C-. is one of them.  There is no fix: itʼs an inherent
limitation of the tty technology.

Robert
-- 

Re: . is undefined (when pressing C-.): is ssh behaving odd?

[Yuri Khan]

On Tue, 7 Dec 2021 at 00:25, Robert Pluim <rpluim@gmail.com> wrote:

>>> tty's canʼt produce 'C-.'

This is technically correct if one limits oneself to a hardware
terminal made half a century ago, or even to a Linux TTY.

> There are limitations to the keys that can be produced when using a
> tty (such as when youʼre logged in over ssh, or running 'emacs
> -nw'). One of those is that certain Ctrl combinations simply won't
> work: C-. is one of them.  There is no fix: itʼs an inherent
> limitation of the tty technology.

The fix is to use a terminal emulator that implements extended key
codes, to opt in to such a protocol extension, and to teach Emacs to
decode that.

Here’s one such extension.
https://sw.kovidgoyal.net/kitty/keyboard-protocol/

(No, I don’t have a functional term/xterm-kitty.el right now. Maybe
one day, when/if I get fed up with X11 forwarding over a
less-than-lightspeed ssh connection.)

Re: . is undefined (when pressing C-.): is ssh behaving odd?

[Emanuel Berg via Users list for the GNU Emacs text editor]

Yuri Khan wrote:

>> tty's can't produce 'C-.'
>
> This is technically correct if one limits oneself to
> a hardware terminal made half a century ago, or even to
> a Linux TTY.

I agree it is an underdeveloped field, unsure if it is any
better in other Unixes but still, however with tmux on top it
can still be pretty good for purposes like Emacs and shell
tools ...

Maybe it "can't produce 'C-.'" but you can still use it in
Emacs, with this method:

  https://dataswamp.org/~incal/tty-emacs-keys.txt

Examples:

  http://user.it.uu.se/~embe8573/conf/vt/remap.inc
  https://dataswamp.org/~incal/emacs-init/console-keys.el

-- 
underground experts united
https://dataswamp.org/~incal

Re: . is undefined (when pressing C-.): is ssh behaving odd?

[Emanuel Berg via Users list for the GNU Emacs text editor]

Robert Pluim wrote:

> tty (such as when youʼre logged in over ssh, or running
> 'emacs -nw'). One of those is that certain Ctrl combinations
> simply won't work [...]

They work, see

  https://dataswamp.org/~incal/tty-emacs-keys.txt
  https://dataswamp.org/~incal/emacs-init/console-keys.el
  https://dataswamp.org/~incal/conf/vt/remap.inc

-- 
underground experts united
https://dataswamp.org/~incal