Side Specific Binding Limitation

[overvale]

Hey! Using (and loving) your side-specific code to help my finger pain. It seems I've run up against a limit, and am wondering if there's a workaround, or if it's unavoidable.

I can't remap a key + modifier to the same key with another modifier. So this doesn't work:

SIDE_SPECIFIC_HOTKEYS = {
  {'rightCmd', 'a', 'ctrl', 'a'},
}

[elliotwaite]

Hey, sorry for the delay in reply. Yeah, for some reason the normal hotkey method doesn't work for mapping hotkeys to a modified version of that same key, but you can work around it by using an eventtap:

keyDownWatcher = hs.eventtap.new({hs.eventtap.event.types.keyDown}, function(event)
  -- Maps rightCmd+a -> ctrl+a. The key code for rightCmd is 54.
  if modStates[54] and event:getKeyCode() == hs.keycodes.map['a'] then
    return true, hs.eventtap.keyStroke('ctrl', 'a', 0)
  end
end):start()

The 54 value is the key code for rightCmd, but if you want to create mappings from other modifier keys, you can find their values in the init.lua file here: https://github.com/elliotwaite/hammerspoon-config/blob/master/init.lua#L30

And if you wanted to require that 2 of modifier keys are pressed, you could and them together, for example, this would detect rightCmd+rightShift+a (the key code for rightShift is 60):

if modStates[54] and modStates[60] and event:getKeyCode() == hs.keycodes.map['a'] then

The return true, hs.eventtap.keyStroke('ctrl', 'a', 0) part returns two values, the first value (true) means that the current event (the 'a' key down event) should be deleted and not propagated, and the second value (hs.eventtap.keyStroke('ctrl', 'a', 0)) is the new event that should be posted, with the 0 value as the third argument meaning that there should be zero delay time between the key down and key up events for that keystroke.

And for when you don't care that it is a side-specific hotkey, you could do something like this, which will get trigger by cmd+a (either cmd) and doesn't depend on the modStates value (which is created and updated by the side-specific code in my init.lua file):

keyDownWatcher = hs.eventtap.new({hs.eventtap.event.types.keyDown}, function(event)
    if event:getFlags():containExactly({'cmd'}) and event:getKeyCode() == hs.keycodes.map['a'] then
        return true, hs.eventtap.keyStroke('ctrl', 'a', 0)
    end
end):start()

Let me know if this solves the issue for you.

Also, thanks for pointing this out. I've added a note about this to the README and comment in the code in case others come across this same issue.

[overvale]

Thanks for the detailed write up! It still boggles my mind what hammerspoon can do.

Your code works for me with the caveat that the new key-stroke isn't performed until one of the modifiers is released.

[elliotwaite]

Strange. For me, it fires the new keystroke on the key down event. There might be a way to fix this for your setup, but I'm not sure how, and since I'm not experiencing that issue, it's hard for me to debug it. But I'll leave this issue open and maybe someone else will be able to suggest a solution.

[overvale]

I tried removing everything except this from my config and still got the same behavior, so I don't think it's a conflict with my config. Thanks for taking a look.

[elliotwaite]

Darn, ok.

[orkhan10]

Thanks for the detailed write up! It still boggles my mind what hammerspoon can do.

Your code works for me with the caveat that the new key-stroke isn't performed until one of the modifiers is released.

I can confirm that it is the same behaviour with me.

Though, for 'ctrl + a' it is not performed until one of the modifier is released, 'shift+left' is performed immediately.
I know it does not solve the problem, just found it interesting.