bug#44973: Add a macOS global hotkey function

[j]

Hi Lars,

I'm pretty close to having a patch ready, but I'm stuck in one key spot. I don't know if anyone on the list could help?

After the user registers a hotkey, and when they press the hotkey, MacOS will run the code below. On the line "RUN_SOME_ELISP_FUNCTION", I would expect some elisp function to be run (e.g. 'emacs-version'). 

But no matter what I do, it always crashes the program. I think my first problem is not knowing how to call elisp (run_hooks, safe_call, etc?) correctly, but second, I suspect if this is crashing due to a threading issue.

    handler = [NSEvent addGlobalMonitorForEventsMatchingMask:(NSEventMaskKeyDown) handler:^(NSEvent *event){

        if (event.modifierFlags & modifier) 

          if([event.charactersIgnoringModifiers characterAtIndex:0] == vkey) {

           RUN_SOME_ELISP_FUNCTION

            [[NSApp mainWindow] makeKeyAndOrderFront:NSApp];

          }

        }

      }];

Is there anyone who might know how to fill in this piece?

Thanks

On Tue, Dec 8, 2020 at 12:39 PM Lars Ingebrigtsen <larsi@gnus.org> wrote:

j@mremus.net writes:

> MacOS makes it very difficult to assign global hotkeys to focus
> Emacs. For example, if I'm in another program, and I want to
> launch/focus Emacs with "Alt-SPC", it can't just be set in the system
> preferences; I'd need to use a 3rd-party program like skhd.
>
> Would it be possible to add a function or hook to Emacs which registers one or
> more global hotkeys (using addGlobalMonitorForEventsMatchingMask), and then
> when the hotkey is pressed, run an elisp function?

[...]

> Even if it's rare for Emacs to implement an OS-specific feature, there
> is some precedent on Windows. If you look at w32-register-hot-keys,
> it's similar to, but different from my request.

Sure, I think that makes sense.  Would it be possible for you to work up
a patch that adds this functionality?

--
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   bloggy blog: http://lars.ingebrigtsen.no