Bindsyms using Mod5 (ISO_Level3_Shift) fail

[frsfnrrg]

Using wlroots & sway builds from today (swaywm/wlroots@12bf39a715b2 and 48c84cd1f).

My relevant environment variables are

  export XKB_DEFAULT_OPTIONS=lv3:caps_switch

And the relevant lines of .config/sway/sway are set $mod Mod5 and bindsym $mod+Return exec st. Pressing keys CapsLock+Enter should launch st; it doesn't. The cause is that keysym_is_modifier in sway/input/keyboard.c is overly specific in detecting modifiers; comparing with xmodmap output, I find

shift       Shift_L (0x32),  Shift_R (0x3e)
lock      
control     Control_L (0x25),  Control_R (0x69)
mod1        Alt_L (0x40),  Alt_R (0x6c),  Meta_L (0xcd)
mod2        Num_Lock (0x4d)
mod3      
mod4        Super_L (0x85),  Super_R (0x86),  Super_L (0xce),  Hyper_L (0xcf)
mod5        ISO_Level3_Shift (0x5c),  Mode_switch (0xcb)

so that keysym_is_modifier is most likely missing XKB_KEY_Num_Lock, XKB_KEY_Mode_switch, and XKB_KEY_ISO_Level3_Shift. (Now that I have added these cases to my local version of sway, CapsLock+Enter does launch st.)

It would be nice if sway would identify which keysyms generate modifiers from the xkb API instead of using using a hardcoded list which only works with default keyboards.

[emersion]

We've not (yet) found a way to do this automatically.

xmodmap -pm is implemented here: https://cgit.freedesktop.org/xorg/app/xmodmap/tree/exec.c#n215

[emersion]

From #wayland:

08:38 <daniels> emersion: yeah, keyboard shortcuts are ... exciting. especially when you get to multiple layouts and realise that people want ctrl+w to work regardless of whether they're in cyrillic or latin mode
08:39 <daniels> emersion: anyway, yeah, there's i'm afraid no real connection between keysyms and modifiers, especially as you have things like latching modifiers

[frsfnrrg]

I've made a short script (https://github.com/frsfnrrg/shortcut/blob/master/shortcut.py) with which to compare shortcut implementations. It requires Python3.6 and xev. So,

• Shortcuts for i3 (⊃ KDE) are group+modifier+keysym or group+modifier+keycode; very simple (see shortcut_i3) hence fast and bug free.
• Sway's current shortcut handling is unintuitive -- it can't distinguish Ctrl+a+b from Ctrl+b+a, and hardcodes modifiers. My translation is shortcut_sway, which skips translated keysyms due to complexity.†
• shortcut_delta is the shortcut behavior that I would prefer; a generalization of i3's behavior to short sequences of key combinations, such as Ctrl+m/Meta+r/Meta+s. A keypress is a modifier keypress if the next key press has a different modifier state.†† We store the last N keypresses which are not modifier keypresses, and match regular shortcuts based on the suffixes of stored keypresses along with the current keypress (which may or may not be a modifier keypress) . (Thus Ctrl+Hyper_L is a valid key combination.) Release shortcuts are triggered on any keyrelease when a stored keypress suffix matches; if multiple do, we pick the shortest match. [In an actual implementation, when a shortcut is triggered, the ring of stored keypresses is wiped so we don't overcall; this can't be shown in the script.]

†(Isn't Unicode case normalization more appropriate? After all, some users might have keyboard states that translate QWERTY to Dvorak, and if they cared for key positions, they'd use bindcode not bindsym) ††Hopefully this would also identify latching modifiers.

[martin-braun]

Thank you for this issue. I wasn't able to bind ISO_Level3_Shift which is the right option key on German Macintosh keyboards, but binding Mod5 worked. This issue was helpful for me.