How can I implement something like a Fn-Lock key for the function keys?

[vonHabsi]

I need a configuration where the Caps key plays the role of the Function key on a 60% keyboard, but more like a Function-Lock key which stays locked until a non Function related key is pressed.

My current adaption is to extend the arrows layer in cfg_samples/minimal.kbd with all the function related keys and use the Caps key to trigger it rather than the grv key. But the tap-hold system requires me keep the grv down all the time, but prefer a mode I can release it but keep that mode locked until a key not in the Fn group is pressed.

Which mode akin to the tap-hold mode is required for that?

[gerhard-h]

I think (one-shot 2000 (layer-while-held Fkeys)) ist what you need.

To do Alt+F4 or other modifiers use one-shot-release-pcancel instead of one-shot.
Or you could change lalt in (multi lalt (layer-while-held Fkeys)) on layer Fkeys
(not sure on mod handling as I don't use one shot myself)

[jtroo]

These threads may be of interest:
#1303
#1306