So I have been recently interested in APL, A Programming Language with unusual characters. One way to write these is to add the APL layout on top of your national layout, and press a modifier key. I have gotten to the point where I can hold CTRL and switch, but how can I use CTRL like a dead key for a single character in the APL layout that switches back after? I was using XKB, but I don't think it is possible to do this specific thing with XKDB.
setxkbmap -option grp:rctrl_switch almost does it.
I am on a GNOME forked GUI (Mate) running openSuse.
Note: I can't just CTRL globally as a dead character unless it is only affecting RCTRL, because I am an Emacs user and that would be detrimental. I don't use RCTRL when I use Emacs, which is why it is open for rebinding. Therefore, activating sticky-keys is not really an option.