Allow suppression of Event::Exit

[toshokan]

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Problem description

The termion backend puts stdout into raw mode which sets -ISIG to prevent the default SIGINT on Ctrl-C. In the event mapping from termion keys to cursive events, Ctrl-C is mapped directly to Event::Exit, and then in on_event on Cursive, Event::Exit is hardcoded directly to quit().

I'm working on a project where I do not want to quit on Ctrl-C (or any other automatic exit event), but it's not straightforward to me how to suppress exit on Ctrl-C with this setup.

Maybe instead of having the top level check for Event::Exit in on_event, this can be preloaded into a default global callback so that it can easily be cleared or overridden?

Sorry if I've missed something and this is already simple to do :^)

Environment

• Operating system: linux distribution, windows, macOS, ... GNU/Linux
• Backend used: ncurses (the default one), pancurses, termion, ... termion
• Current locale (run locale in a terminal). en_US.utf8
• Cursive version (from crates.io, from git, ...) 0.13.0 from crates.io

[gyscos]

Hi, and thanks for the report!

That's a very good point, this ctrl-c forced handling does feel like it should be more flexible. A default global callback sounds like a great idea!

EDIT: Also, rather than hard-coding Ctrl-C to Exit in the backend and registering Exit -> Cursive::quit in the callback, we can just register Ctrl-C -> Cursive::quit in the callback, and drop the special handling in the backend entirely.

Some backends may still emit Exit (I think BearLibTerminal may do so when the window is closed).

[gyscos]

On the latest master I use a regular OnEventView for the global callbacks. This lets us define pre and post-events, so we can now define the Ctrl-C callback as a pre-callback, which can be suppressed with Cursive::clear_global_callbacks (this will wipe both pre- and post- callbacks for this event).

[jacob-pro]

I'm not sure that the clear global callbacks method is working as expected. I am using siv.clear_global_callbacks(Event::CtrlChar('c')); However it does not actually remove the existing pre_event added in reset_default_callbacks

[gyscos]

Indeed! Seems like the Any dance around event identification didn't quite work quite as intended - should be all better on the latest master. Thanks for pointing that!