Making the physical <NumLock> key available for use in the EDT Emulation requires some modification to the default X Window settings. Since the keycode assignments vary from system to system, some investigation is needed to see how to do this on a particular system.
You will need to look at the output generated by
with the "-pm" switch. For example, on RedHat GNU/Linux 5.2 on a PC, we
get the following output when running ‘xmodmap -pm’:
xmodmap: up to 2 keys per modifier, (keycodes in parentheses): shift Shift_L (0x32), Shift_R (0x3e) lock Caps_Lock (0x42) control Control_L (0x25), Control_R (0x6d) mod1 Alt_L (0x40), Alt_R (0x71) mod2 Num_Lock (0x4d) mod3 mod4 mod5 Scroll_Lock (0x4e)
Note that Num_Lock is assigned to the modifier ‘mod2’. This is what hides Num_Lock from being seen by Emacs.
Now, ‘xmodmap -pke’ yields:
. . . keycode 77 = Num_Lock Pointer_EnableKeys . . . keycode 96 = F12 . . .
So, in RedHat GNU/Linux 5.2 on a PC, Num_Lock generates keycode 77. The following steps are taken:
The .xmodmaprc file looks like this:
! File: .xmodmaprc ! ! Set up PC keypad under GNU/Linux for the Emacs EDT Emulation ! clear mod2 keycode 77 = F12 keycode 96 = Num_Lock Pointer_EnableKeys add mod2 = Num_Lock
So, after executing ‘xmodmap .xmodmaprc’, a press of the physical <F12> key looks like a Num_Lock keypress to X. Also, a press of the physical <NumLock> key looks like a press of the <F12> key to X.
Now, edt-mapper.el will see ‘f12’ when the physical <NumLock> key is pressed, allowing the <NumLock> key to be used as the EDT <PF1> (<GOLD>) key.