kc3-lang/libxkbcommon

2024-02-14T09:47:15

keymap: Canonically map unmapped virtual modifiers Traditionally, *virtual* modifiers were merely name aliases for *real* modifiers (X *core* modifiers), e.g. `NumLock` was usually mapped to `Mod2` (see `modifier_map` statement). Virtual modifiers that were never mapped to a real ones had no effect on the keymap state. xkbcommon already supports the concept of “pure” virtual modifiers, i.e. virtual modifiers that are *encoded* using the full 32-bit range, not just the first 8 bits corresponding to the real modifiers. But until this commit, one had to declare such mapping *explicitly*: e.g. `virtual_modifiers M = 0x100;`. This has at least two drawbacks: - Numerical values may look quite arbitrary and are not user-friendly. It’s OK in the resulting compiled keymap, but it requires careful sync between sections when developing KcCGST files. - If the modifier is *also* mapped *implicitly* using the traditional `vmodmap`/`modifier_map`, then both mappings are OR-combined. This patch enables to automatically map unmapped virtual modifiers to their *canonical* mapping, i.e. themselves: their corresponding virtual and real modifier masks are identical: `1u << mod_index`. Since this feature is incompatible with X11, this is guarded by requiring at least keymap text format **v2**. Note that for now, canonical virtual modifiers cannot be used in an interpret action’s `AnyOf()`. An interpret action for a canonical virtual modifier must be `AnyOfOrNone()` to take effect: virtual_modifiers APureMod, …; interpret a+AnyOfOrNone(all) { virtualModifier= APureMod; action= SetMods(modifiers=APureMod); }; The above adds a virtual modifier `APureMod` for keysym `a`. It will be canonical iff it is not mapped implicitly.