Gfilui

I wanna emulate numpad on letters uiojklm,.

I edited french layout in /usr/share/X11/xkb/symbols (see image below).

But I have to switch layout in order to use what I've done there.

I would like if for certain layout I could just hold Alt.

There is two options how I would like to switch to numbers:

-change to certain layout while holding Alt;

-keys print different symbols while holding Alt;

(or after activating Caps Lock)

I edited the English (US) keyboard layout like this:

$ diff /usr/share/X11/xkb/symbols/us.orig /usr/share/X11/xkb/symbols/us
26,28c26,28
< key <AD07> [ u, U ] ;
< key <AD08> [ i, I ] ;
< key <AD09> [ o, O ] ;
---
> key <AD07> [ u, U, 7 ] ;
> key <AD08> [ i, I, 8 ] ;
> key <AD09> [ o, O, 9 ] ;
39,41c39,41
< key <AC07> [ j, J ] ;
< key <AC08> [ k, K ] ;
< key <AC09> [ l, L ] ;
---
> key <AC07> [ j, J, 4 ] ;
> key <AC08> [ k, K, 5 ] ;
> key <AC09> [ l, L, 6 ] ;
51,53c51,53
< key <AB07> [ m, M ] ;
< key <AB08> [ comma, less ] ;
< key <AB09> [ period, greater ] ;
---
> key <AB07> [ m, M, 1 ] ;
> key <AB08> [ comma, less, 2 ] ;
> key <AB09> [ period, greater, 3 ] ;
56a57,58
> 
> include "level3(ralt_switch)"

That way I can type numbers like this:

Right Alt+U -> 7

Right Alt+K -> 5

etc.

The line

include "level3(ralt_switch)"

enables the third level mechanism; in this case Right Alt which is default for those keyboard layouts which make use of third and fourth level symbols, but it can be changed.