Shift on console

Shift on console

[Robert J. Chassell]

Shift fails on my console.  I cannot run C-M-S-v
(scroll-other-window-down) on it although I can run it on both an
Xterm and on RXVT

    Today's GNU Emacs CVS snapshot, Sun, 2008 Mar 16  10:46 UTC
    GNU Emacs 23.0.60.22 (i686-pc-linux-gnu, GTK+ Version 2.12.5)
    started with
         src/emacs -q in the console

    started with
         src/emacs -q -nbc -nw in the Xterm and on RXVT

All as a regular user using BASH.

-- 
    Robert J. Chassell                          GnuPG Key ID: 004B4AC8
    bob@rattlesnake.com                         bob@gnu.org
    http://www.rattlesnake.com                  http://www.teak.cc

Re: Shift on console

[Alan Mackenzie]

'Evening, Robert!

On Sun, Mar 16, 2008 at 06:34:42PM +0000, Robert J. Chassell wrote:
> Shift fails on my console.

Where "console" = ????

I have had this problem on my GNU tty (which might be the same as your
console, but probably isn't).

> I cannot run C-M-S-v
> (scroll-other-window-down) on it although I can run it on both an
> Xterm and on RXVT

On a GNU tty, this has the same cause as not having C-<up> or M-<down>:
the standard keyboard layout discards the modifier keys.  :-(

The solution is to add stuff to a keymap (in the sense of Linux's
loadkeys) and add stuff to Emacs's function-key-map to parse this.  For
example, I've got the following lines in my boottime.kmap.gz for
C-M-S-a:

keycode  30 = a
        AltGr   keycode  30 = +adiaeresis    # ä ACM 11/7/99
        Shift AltGr keycode 30 = +Adiaeresis # Ä ACM 11/7/99
        control alt shift keycode 30 = F214          <================
.........
string F214 = "\033[7>a"         # Control+Alt+Shift+a

> All as a regular user using BASH.

This problem is going to become really problematic if "shift-movement
selection" becomes the Emacs default".

[ .... ]

>     Robert J. Chassell                          GnuPG Key ID: 004B4AC8

-- 
Alan Mackenzie (Nuremberg, Germany).

Re: Shift on console

[Robert J. Chassell]

Alan Mackenzie <acm@muc.de> asked

    Where "console" = ????

/dev/tty2, also known by the Debian folks and others as a `virtual
console'.  It does not have X or any other windowing system and is
what we once called a `terminal'.

    This problem is going to become really problematic if "shift-movement
    selection" becomes the Emacs default".

Perhaps others expect a graphical windowing environment in all
circumstances.  

When I SSH to gnu.org and log into it with an RXVT shell on my local
machine, and invoke Emacs on fp.gnu.org, I can run C-M-S-v
(scroll-other-window-down), that is to say, the shift key succeeds;
but when I do the same in a plain console -- no RXVT shell -- I
cannot.

-- 
    Robert J. Chassell                          GnuPG Key ID: 004B4AC8
    bob@rattlesnake.com                         bob@gnu.org
    http://www.rattlesnake.com                  http://www.teak.cc

Re: Shift on console

[Alan Mackenzie]

Hi, Robert!

On Mon, Mar 17, 2008 at 12:49:27AM +0000, Robert J. Chassell wrote:
> Alan Mackenzie <acm@muc.de> asked

>     Where "console" = ????

> /dev/tty2, also known by the Debian folks and others as a `virtual
> console'.  It does not have X or any other windowing system and is
> what we once called a `terminal'.

>     This problem is going to become really problematic if "shift-movement
>     selection" becomes the Emacs default".

> Perhaps others expect a graphical windowing environment in all
> circumstances.  

> When I SSH to gnu.org and log into it with an RXVT shell on my local
> machine, and invoke Emacs on fp.gnu.org, I can run C-M-S-v
> (scroll-other-window-down), that is to say, the shift key succeeds;
> but when I do the same in a plain console -- no RXVT shell -- I
> cannot.

In my last post when I said "GNU tty", I actually meant "Linux tty".
Sorry!  (Who's been getting me confused between GNU and Linux?  ;-)

There is actually a feature/bug/misfeature (I'd say bug), in
event-apply-modifier (simple.el), which forces C-a and C-A (possibly
with more modifiers) to be identical, namely 0x01.  I've been using the
following function instead, which sets b25 (the <shift> bit) on C-S-a:
("kn" stands for Kalle Niemitalo, BTW, who worked out most of this stuff
~10 years ago).

(defun kn-event-apply-modifier (event symbol lshiftby prefix)
  "Apply a modifier flag to event EVENT.

Unlike the core Emacs function `event-apply-modifier', when both
<control> and <shift> are modifying a\(n English\) letter in an
event, b25 is set (for shift), and the LSB contains C-<letter>.

SYMBOL is the name of this modifier, as a symbol.
LSHIFTBY is the bit position of the modifier bit; e.g. 25 means 0x2000000.
PREFIX is the string that represents this modifier in an event type symbol."
  (if (numberp event)
      (let ((letter (logand event 4194303))) ; 2^22 - 1
        (if (eq symbol 'control)
            (cond ((and (>= letter ?A) (<= letter ?Z))
                   (- (logior (lsh 1 25) event) ?A -1)) ; add <shift>
                  ((and (>= letter ?a) (<= letter ?z))
                   (- event ?a -1))
                  ((and (>= letter ?\C-a) (<= letter ?\C-z))) ; do nothing
                  (t (logior (lsh 1 lshiftby) event)))
          (logior (lsh 1 lshiftby) event)))
    (if (memq symbol (event-modifiers event))
        event
      (let ((event-type (if (symbolp event) event (car event))))
        (setq event-type (intern (concat prefix (symbol-name event-type))))
        (if (symbolp event)
            event-type
          (cons event-type (cdr event)))))))

>     Robert J. Chassell 

-- 
Alan Mackenzie (Nuremberg, Germany).