Notes from Discord.

I recently found that, at least on Linux, the quit handler application-quit-handler only closes the most recent window :/ not quite what I was expecting.

But apparently I’m holding it wrong:

[we’re not] intended to call the application-quit-handler from code. Instead, I think it is a hook for reacting to requests from the desktop environment that the application please quit, just as the other handlers documented in that section respond to other events from the environment. In particular:

The default handler queues a call to the can-exit? method of the most recently active frame in the initial eventspace (and then calls the frame’s on-exit method if the result is true). The result is #t if the eventspace is left with no open frames after on-exit returns, #f otherwise.

(Documentation on Windowing Functions)

Which of course makes quite a bit more sense, and should probably be stated in documentation.

I had wanted to use it as the action for my “File > Quit” menu, which now just uses exit (I have no special cleanup to do for the moment).

I know macOS automatically provides a Quit option on .apps, which I suppose is an example of a “request[] from the desktop environment.” Do other DEs do something similar? My Gentoo box is currently running i3 without a DE, so I don’t know what typical Linux/Gtk behavior is, for example. Although a good many programs don’t have a close/quit button, which seems to imply they assume the DE will provide one. (I have keys in i3 to close them in that case.)

The framework module uses file-menu:quit-callback which “by default goes through the exit-related hooks in the framework.”

On non-Mac platforms, applications are supposed to add a “File > Quit” item themselves: see file-menu:create-quit? from framework. But DEs do have other ways to ask an application to quit. The application-quit-handler docs don’t mention other Unix, but, on KDE, right-clicking on DrRacket’s icon in my task bar and choosing Quit definitely goes through some graceful mechanism prompting me to save or cancel. Likewise if I’m logging out or rebooting. IIRC there’s an XDG spec for how to ask an application to quit.

And others say

For the File > Exit menu option in Molasses (which should probably be File > Quit), I do (send frame on-exit). The default on-exit handler will in turn call on-close, which I overrode and put my custom Exit/Quit code.

This seems quite sensible also.

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