Feature request: customize shift behaviour per key

[Mojken]

Some layouts, such as dvp, don't always have the shift button do the same thing as on qwerty for all buttons. I've noticed in general that only letters are actually affected by shift. This is especially an issue for narrow (9-key inspired) layouts, as emulating the funcionality with swipes isn't an option.

[Julow]

The shift modifier can be customized per layout (22d407c4) but I might want to remove it in the future if its original use case can be implemented in an other way. It's currently not used in any known layout.

What about adding more keys to your layout ? It's also possible to add more combinations to shift and fn or to create new modifiers.

[Julow]

Have you been able to make use of this feature ?

[Spike-from-NH]

If you mean <modmap>, I've begun using it in custom layouts, as mentioned in #513, though I could adapt if it went away.