Yes modifiers are a state, not a key. The kitty keyboard protocol does indeed send events for left and right modifier key press/releas as you can easily see for yourself by running
kitten show-key -m kitty
in a kitty terminal and pressing the left and right modifier keys.
So why are you talking about a key then??? Kitty doesn't support left/right modifiers unlike proper keybinding handling apps, the left/right presses for non-modifier keys aren't relevant
How would you bind LeftAlt-A to something different from RightAlt-A in Kitty?
There is no such thing as a left or right modifier STATE in ANY application. All applications, including kitty track only CTRL, SHIFT, ALT, ETC modifier states. left and right alt and control are key events and can be bound in any application supporting the kitty keyboard protocol as key events. If some application tracks a left and right modifier state it has to do so manually using key press and release events, the OS does not supply it any such state.
You seem to be thoroughly confused about what is a modifier and what is a key. Left and right ctrl/alt/shift are KEYS not MODIFIERS. You can track whether they are held down or up by tracking their press and release events just like for any other key.
This rigid simplistic attitude is precisely why we can't have nice keyboard things and have been stuck in the same state of bad defaults for decades
The only differentiator for a modifier state is that it... modifies! Here is a wiki common sense definition
> In computing, a modifier key is a special key (or combination) on a computer keyboard that temporarily modifies the normal action of another key when pressed together
So your limitations don't make conceptual sense, not only can you have LShift vs RShift modifier state, but also you can have an F modifier state when you hold down the F key to modify the behavior of other keys
> OS does not supply it
Unless it does?
> VK_LSHIFT VK_RSHIFT VK_LCONTROL VK_RCONTROL VK_LMENU VK_RMENU These left- and right-distinguishing constants are available to an application only through the GetKeyboardState, SetKeyboardState, GetAsyncKeyState, GetKeyState, and MapVirtualKey functions.
ROFL you are saying that kitty the program that finally broke the keyboard logjam with terminals of preventing you from having nice things!! Good luck to you.
And lets apply some common sense to your common sense, follow up on it a little. If a modifier is defined by the fact that it modifies the actions of other keys, then left and right modifer keys modify the action in exactly the same way and thus are the same modifier. Common sense indeed.
no left and right modifier state on macOS. And neither does X11/Wayland have them, though I dont have a link handy, so I will just leave you with a couple of links to the documentation for cross platform toolkits instead:
And in case the common sense didnt make it past your mental barriers, a terminal keyboard protocol has to work on all platforms not just windows.
The good lord alone knows what windows does, probably synthesizes that state based on press and release events.
https://sw.kovidgoyal.net/kitty/keyboard-protocol/
Modifiers are encoded as a bit field with:
shift 0b1 (1) alt 0b10 (2) ctrl 0b100 (4) super 0b1000 (8) hyper 0b10000 (16) meta 0b100000 (32) caps_lock 0b1000000 (64) num_lock 0b10000000 (128)